Although the published economic evaluations identified in the economic literature review addressed the interventions of interest, they did not use Canadian costs, nor did the authors take a Canadian perspective. Owing to these limitations, we conducted a primary economic evaluation using Ontario-specific cost inputs and clinical care pathways.
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Finally, we conducted a scenario analysis where all implant surgeries were single-stage instead of two-stage. We estimated that compared to two-stage surgery, single-stage surgeries would have lower costs, as they would have reduced inpatient stays and would not require multiple operating room days to complete the procedure. As there is currently no published literature evaluating single-stage osseointegrated prosthetic implant surgery for lower-limb amputees, the model assumed the same clinical effectiveness, utility gains, and complication rates as two-stage surgery.
We excluded disutilities from the reference case as they used measurement methods (i.e., EuroQol [EQ-5D] and Assessment of Quality of life [AQoL] instruments) that differed from the rest of the core model utility values, which were derived from the SF-6D survey. In a scenario analysis, we used disutilities found in the literature for fractures and deep infections. In the model, when a complication occurred in a health state, the state was assigned a disutility value representative of the amount of time individuals would be affected by the complication. The resulting QALYs incurred were calculated as the utility value of the current health state, minus the utility value of the complication multiplied by the duration of the complication (representing the disutility). For example, to calculate the change in QALYs for an individual who is in the &#;osseointegrated prosthesis&#; health state and who has a fracture during one model cycle, 0.692 would be subtracted by the result of 0.120 &#; 0.5 (with 0.5 representing 6 of 12 months), which would result in a QALY of 0.632. 26 , 57 We also tested alternative utility values for the health states in additional scenario analyses.
We pooled event rates for the reference case, as the available studies were of equally low quality and reported varying event rates. In a scenario analysis, we used time-varying event rates from Branemark et al. 10 Expert opinion informed us that the risk for complications (e.g., superficial and deep infection), although always present, may be higher immediately following surgery (James Waddell, MD, communication, September ). We calculated time-varying rates for 0 to 12 months postsurgery and 12 to 24 months postsurgery. Rates at 0 to 12 months were assigned to the health states of &#;implant surgery and recovery&#; and &#;reimplant,&#; while rates at 12 to 24 months were assigned to the health state &#;osseointegrated prosthesis.&#;
The reference case parameter for stump revision rates came from a previously published cost&#; utility analysis that cited rates from hospital data. 45 Furthermore, we were unable to determine a measure of uncertainty around the estimate. Therefore, in a scenario analysis we used the soft tissue refashioning rate in the osseointegration cohort for the stump revision rate in the socket cohort.
The reference case included costs for femoral fractures but only for the osseointegration cohort, due to insufficient data on the rate of femoral fractures among socket prosthesis users. But that assumption may overestimate the costs for patients with osseointegrated prosthetic implants if the fracture rate in a socket cohort is not close to zero. Therefore, in a scenario analysis, we excluded fractures to consider the possibility that the two cohorts have similar risk of fracture and that the incremental cost difference for treatment is marginal.
As identified in the clinical evidence section of this report, a deep infection required surgical intervention in all cases in the literature. Our reference case assumed that patients with deep infection stayed in hospital an average of 9.9 days for postoperative care, but clinical experts indicated that IV antibiotics could be administered in an outpatient or home care setting (Nancy Dudek, MD; Wade Gofton, MD; communications, November ). Therefore, a scenario analysis considered this possibility, and based on the results of Wolter et al, 56 we assumed home care expenses would be half the cost of an inpatient stay.
We modelled differences in maintenance cost in the scenario analysis, such as the number of visits to a prosthetist, as outlined by Haggstrom et al, 52 by assuming 7 visits to a prosthetist per year for a socket user and 3 visits for an implant user. The costs were calculated by using the hourly fee for a prosthetist in Ontario ($183.29/hour) and assuming each adjustment session takes 1 hour for an implant user and 2 hours for a socket user (Nancy Dudek, MD, communication, August ).
As a conservative assumption, the model currently incorporates the costs of both inpatient and outpatient rehabilitation after implant surgery. However, due to the intensive inpatient rehabilitation process, it is possible that patients may not require additional rehabilitation services in the outpatient setting. Therefore, we explored excluding it in a scenario analysis.
As described in , we conducted several scenario analyses. Given that osseointegrated prosthetic implant surgery has yet to be performed in Ontario, these scenario analyses tested not only different input parameters, but also some of the assumptions required to estimate Ontario-specific costs. For each scenario, we recalculated the mean incremental costs and QALYs for each treatment, along with the ICER. All scenarios were performed probabilistically unless otherwise stated. Appendix 6 , and , provide a full list of input parameters.
We conducted deterministic sensitivity analyses to assess how sensitive our reference case results were to specific parameters. In the one-way sensitivity analyses, we varied specific model variables (e.g., transitional probabilities, costs, utilities) and recorded and presented their impact on the results in a tornado diagram. Details of these analyses and the specific parameters varied are presented in Appendix 6 , .
For the reference case analysis, we performed a probabilistic analysis to determine the mean incremental cost and mean incremental QALYs, and we calculated the incremental cost-effectiveness ratio (ICER) for an osseointegrated prosthesis compared with an uncomfortable socket prosthesis. We performed a probabilistic sensitivity analysis by running 5,000 Monte Carlo simulations to capture parameter uncertainty. When possible, we specified distributions around each estimate, using the mean and standard deviation. Costs were characterized by gamma distributions, and probabilities and utilities were characterized by beta distributions.
describes costs for complications. We assumed all complications except superficial infections were treated in an inpatient setting. Femoral fractures can be subdivided into fractures requiring fixation (stable stem) and complex fractures requiring fixation and implant revision (unstable stem). As the rates of femoral fracture related to osseointegrated prosthetic implants reported in the literature did not differentiate between stable and unstable stems, we assumed the rate for implant revision would include fractures requiring both fixation and implant revision; therefore, femoral fractures were costed as requiring only fixation (i.e., for people with these fractures, an implant revision is unnecessary). For superficial infections, we assumed patients would visit their physiatrist and receive a prescription for antibiotics. Patients with a deep infection would be admitted to a hospital and undergo a debridement procedure.
contains the costs components of the remaining model health states (i.e., osseointegrated prosthesis, implant extraction, reimplant, uncomfortable socket prosthesis). In both the &#;osseointegrated prosthesis&#; and &#;uncomfortable socket prosthesis&#; health states, we assumed patients would have a yearly physiatrist check-up. However, when costing physiatrist visits for complications, we assumed the socket cohort had 4 annual visits, while the osseointegration cohort had their physiatrist visits built into the model whenever a complication occurred (Nancy Dudek, MD, communication, August ). Fixing the number of physiatrist visits for socket-related complications was necessary as few complication rates were available in the literature to inform the model, yet experts indicated this population would be frequently seen for active problems such as socket pain and cysts (Nancy Dudek, MD; James Waddell, MD; communications, August to September ). For the &#;reimplant&#; health state, we assumed that inpatient costs and prosthetic fitting would both cost 25% less than the initial implantation. Expert consultation indicated that rehabilitation following reimplantation would go through the same progressive weight-bearing following a repeat surgery, but there would be no need for additional gait training once full weight-bearing was achieved, as the patient would have already learned how to optimize their walking pattern (Nancy Dudek, MD, communication, August ).
presents itemized costs for the &#;implant surgery and recovery&#; health state, which includes patients who undergo a two-stage osseointegration surgery and rehabilitation. Costs include the implant system, diagnostic testing for screening eligibility, professional service fees during hospitalization, inpatient hospital costs (including rehabilitation), prosthetist services, and outpatient care. As this procedure has not been conducted in Ontario and there are no specific billing codes, we estimated the costs using proxies informed by expert opinion (Nancy Dudek, MD; Richard Jenkinson, MD; Dan Mead, CP(c); Amanda Mayo, MD; James Waddell, MD; Wade Gofton, MD; communications, August ). As shown in , the cost of the implant system was derived from a surgical group in Montreal who conducted the first osseointegrated prosthetic implant surgery in Canada (Natalie Habra, MD, communication, June ). After expert consultation, we assumed that postsurgical rehabilitation was provided in an inpatient setting, due to the anticipated need for nursing support with dressing changes and the intensive rehabilitation process (Nancy Dudek, MD, communication, August ). Furthermore, given the specialized nature of the surgery for a low annual volume of patients, we assumed the surgery would be conducted in a select number of specialty hospitals across the province, which would make outpatient rehabilitation inequitable for patients travelling long distances for the procedure. Finally, prosthetist fees could not be directly estimated using the Limb Prostheses (Conventional) Product Manual 53 from the province's Assistive Device Program (ADP), so we used hourly rates for clinical ($183.29/hour) and technical ($126.22/hour) prosthetic services in Ontario (as described in the product manual under &#;modifications not listed&#;). 54 This information, alongside the estimated time for services required by patients with osseointegrated prosthetic implants described in Frossard et al, 55 provided a cost estimate for prosthetic services. The model incorporated only 75% of the total cost of prosthetic services; the ADP requires patients to cover the remaining 25%, and, because the model took the perspective of the Ministry of Health and Long-Term Care, we excluded out-of-pocket expenses.
Due to the comparative nature of this analysis, we used several costing assumptions to simplify the analysis. We did not include the cost of replacing prosthesis components over time, because we assumed patients in both cohorts used the same external components. Since all individuals receiving osseointegrated prosthetic implants were prior socket users, we excluded the cost of a socket prosthesis device, because this cost would be incurred prior to the implant procedure. Costs of screening to determine patients' eligibility for implants and training costs for surgeons were assumed to be out of scope and were not included. We did not evaluate bilateral osseointegrated prosthetic implants compared to bilateral socket prostheses due to a lack of utility data specific to bilateral amputees and the assumption that the results of a single implant would provide a valid approximation of the results for bilateral implants. We did not include minor procedures along the patient pathway (e.g., staple removal at 3 to 4 weeks postsurgery), due to a lack of costing data and to simplify the model. Personal support workers and home care between the two stages of implant surgery were not costed, because clinical experts indicated that home care would be necessary only in the event of rare complications with wound healing that would require long-term dressings, which would also likely result in implant failure (James Waddell, MD; Amanda Mayo, MD; John Murnaghan, MD; Wade Gofton, MD; communications, September to November ). Finally, we did not account for differences in maintenance costs in the reference case analysis, such as the number of visits to a prosthetist as outlined by Haggstrom et al, 52 due to both insufficient patient-level data and data on the average cost per prosthetist visit. However, we did conduct a scenario analysis to test this assumption.
All costs were reported in Canadian dollars. We obtained cost inputs from standard Ontario sources and published literature. The fees for professional visits, procedures and consultations were obtained from the Ontario Schedule of Benefits for Physician Services. Hospitalization costs were obtained from the Ontario Case Costing Initiative (OCCI). Diagnostic and laboratory fees were obtained from the Ontario Schedule of Benefits for Laboratory Services.
Utilities represent a person's preference for certain health outcomes, such as being able to walk. These are often measured on a scale of 0 (death) to 1 (full health). summarizes utility data specific to each health state. All studies evaluating individuals' quality of life before and after two-stage osseointegration used the 36-Item Short Form Health Survey (SF-36). To obtain utilities, the studies converted SF-36 values to the SF-6D, a six-domain version of the survey. In cases where only the mean SF-36 domain scores were available, we obtained the utility value by using equation 1 in an SF-36 to SF-6D map/crosswalk published by Ara et al. 51 Hagberg et al 26 was the only study reporting a direct utility value using the SF-6D, and we therefore chose it for the reference case analysis. Utilities from other sources that used a crosswalk were used in scenario analyses. In the reference case, we conducted a probabilistic analysis and used a beta distribution around the values of the mean and standard error.
We performed a targeted literature search in MEDLINE for utility values on June 11, , for studies published from inception to the search date. We based the search on the clinical search strategy with a methodological filter applied to limit retrieval to health state utility values. 50 A second utilities search was conducted on June 27, , to retrieve studies on leg prosthetics using the same filter. See Appendix 1 for our literature search strategies, including all search terms.
The model assumed equal mortality rates for the two cohorts. Although the broad cohort of conventional socket prosthesis users has a higher mortality rate, this is in part due to vascular comorbidities such as diabetes and heart disease, which would preclude an individual from meeting eligibility criteria for an osseointegrated prosthetic implant (see Appendix 6 , ). However, because most osseointegration procedures are conducted several years postamputation, and our model compared a hypothetical population of the same patients who either remained as socket prosthesis users or converted to osseointegrated prosthetic implants, we assumed the survival rate was comparable for both treatments. Given that the average age of the target population for osseointegrated prosthetic implants is 46 years old and the procedure has strict eligibility criteria, this created a subpopulation of relatively healthy individuals; therefore, we used age- and sex-specific mortality rates from the Ontario general population. 49 Clinical experts verified this assumption because inputs for the alternative method&#;mortality rates or hazard ratios specific to a population with nonvascular amputation&#;were not available in the literature (Richard Jenkinson, MD; Nancy Dudek, MD; Amanda Mayo, MD; John Murnaghan, MD; : communications, August to November ).
contains the rates from multiple sources for complications in both cohorts. Due to a lack of data, we could not derive the risk of fractures for patients with an uncomfortable socket, but we included fractures in the model as they were expected to have a greater cost in the osseointegration cohort compared with the socket cohort. Given this potentially conservative estimate for osseointegrated prosthetic implants, we conducted a sensitivity analysis that excluded fractures from the model in the event the risk of fracture is similar between cohorts and the incremental cost difference for treatment is marginal. Treatment pathways for deep infections involved either IV antibiotics alone, IV antibiotics and debridement (with variations in whether the debridement was conducted as inpatient or day surgery). Unfortunately, the rates found in the literature did not differentiate between these pathways, so the model conservatively assumed that patients received IV antibiotics and debridement in an inpatient setting. We tested this assumption in scenario analyses, where we assumed that IV antibiotics were administered in a home-care setting. Given the lack of data on complications for users of conventional socket prostheses, specifically in a population with nonvascular amputations, only stump revisions were included as a complication for the socket cohort.
summarizes transitions between health states in the model, derived from pooled rates. All transitions not explicitly mentioned in the table but found in (i.e., osseointegrated prosthesis and reimplant) are calculated as the complement of the sum of the other branch probability, which is calculated by subtracting the probability found in from the value 1.00.
In our economic evaluation, we considered the impact of costs and quality of life associated with both treatments. We included adverse events that are severe, expensive to treat, or have a large impact on patients' health-related quality of life (e.g., infection, soft-tissue refashioning, implant extraction, fracture, stump revision). We excluded adverse events that have a negligible impact on health effects or resources (e.g., skin rash, blisters, cysts). Other complications considered for conventional socket prostheses included pressure ulcers, neuromas, fungal infections, and mechanical limb pain, but we could not find incidence rates for these complications. Nevertheless, we assumed these chronic conditions were represented by the published utility value for users of an uncomfortable socket prosthesis. Despite the lack of incidence rates, the complication rate may be similar between the socket and osseointegration cohorts, as it has been stated that in osseointegration patients, &#;infection and irritation of the soft tissue in the skin penetration area are common during the first 2 years.&#; 27 Regardless, if the previously published stump revision rates are not inclusive to pressure ulcers and neuromas, the economic model may be underestimating the total cost of the socket prosthesis cohort.
Expert consultants advised that the &#;implant extraction&#; health state could be treated similarly to joint arthroplasty infections: the infected prosthesis is removed during an initial debridement, a temporary prosthesis is fitted, and patients are treated with intravenous (IV) antibiotics and then considered for reimplantation (Richard Jenkinson, MD; Amanda Mayo, MD; John Murnaghan, MD; Nancy Dudek, MD; Wade Gofton, MD; communications, August to November ). This process, although specific to an extraction due to infection, was estimated to take 6 to 12 months. Although other causes have been identified for reimplantation, our model assumed this process would take 12 months (i.e., the model's cycle length). This assumption provided a conservative estimate of the QALY gain in the osseointegration cohort, penalizing implant extractions.
The osseointegration cohort began in the &#;implant surgery and recovery&#; health state, where they underwent surgery and rehabilitation. Patients could then transition to either &#;osseointegrated prosthesis&#; or &#;implant extraction.&#; In the &#;osseointegrated prosthesis&#; health state, patients had full use of their prosthesis but were still at risk of transitioning to &#;implant extraction.&#; Anytime they were in the &#;implant surgery and recovery&#; and &#;osseointegrated prosthesis&#; health states, patients were at risk for complications specific to osseointegration, which included soft-tissue problems, fractures, superficial infections, and deep infections. These complications had distinct costs assigned to their occurrence. We assumed that patients in the &#;implant extraction&#; health state would not be susceptible to implant-related complications, given that the implant was extracted (no complications were identified in the literature specific to implant extraction). In the &#;implant extraction&#; health state, the implant failed and was removed. Some patients then transitioned to the &#;reimplant&#; health state to have the implant reinserted, but a proportion who were no longer suitable for osseointegration permanently returned to their original socket prosthesis and remained in the &#;uncomfortable socket prosthesis&#; health state. In that state, as previously mentioned, patients were at risk for stump revisions, a complication specific to socket prosthesis users.
We modified a previously published Markov decision-analytic model structure from Hansson et al 45 to estimate the long-term clinical and economic outcomes of osseointegrated prosthetic implants for lower-limb amputees. The cycle length was 1 year, because patients are usually monitored annually by a physiatrist (Nancy Dudek, MD; Amanda Mayo, MD; John Murnaghan, MD; communications, August to November ). We applied a half-cycle correction on all health-state transitions. The model was built using TreeAge Pro 48 and repeated cycling until the time horizon was reached.
We used a lifelong time horizon in the reference case analysis, given the chronic nature of the health condition and intervention, thus capturing all health effects and costs relevant to the decision problem. We also conducted sensitivity analyses around the time horizon, including a 10-year time horizon, which approximates the longest average follow-up recorded in an observational study on osseointegrated prosthetic implants. 30 Additionally, we used time horizons from other cost&#;utility analyses of 6 years and 20 years in sensitivity analyses. 44 , 45
To further refine the scope of this analysis, we also excluded certain variations of osseointegrated prosthetic implants. For example, we did not cost implants combined with total hip replacement and total knee replacement, due to a lack of available data. Furthermore, this analysis excluded customized implants not commercially available, also due to a lack of available data. summarizes the interventions evaluated in the economic model.
For this economic evaluation, we evaluated the cost-effectiveness of both two-stage and single-stage osseointegration surgery. However, given the data available, we compared the two-stage procedure to conventional socket prostheses in the reference case, and evaluated the single-stage procedure in a scenario analysis. Despite the absence of published literature on single-stage surgery, it appears to be a technological innovation, as the first osseointegration surgery conducted in Canada was a single-stage surgery performed in Montreal in March . In modeling single-stage surgery in a scenario analysis, given the absence of published evidence, we assumed complication rates and effectiveness equal to the two-stage procedure; therefore, we pooled two-stage data and used them as estimates for the single-stage model inputs.
As described in the Background section of this report, unlike a conventional leg prosthesis that uses a specially fitted cup-like shell (socket) that fits over the remaining portion of the residual leg, osseointegrated prosthetic implants are inserted into an amputee's remaining bone to connect the bone to an external prosthetic limb. The implant systems include an intramedullary component that integrates with the bone, and a bridging connector (also called an abutment) that connects from one side to the intramedullary implant and from the other side to the prosthetic limb. Traditionally, the treatment requires two operations: the first inserts the intramedullary implant, and the second, performed 6 to 9 months later, creates a percutaneous skin opening allowing for abutment attachment and prosthesis fitting. 7 However, the duration between surgeries has been reduced in more recent publications, with the overall time between surgeries being approximately 6 to 8 weeks. 32 Recently, a group in Australia has published a protocol describing a single-stage surgery for osseointegration that they have been conducting since April . 7 Despite this development, no published papers are available on the effectiveness of single-stage osseointegration, outside of a protocol from the OGAAP-2 (Osseointegration Group of Australia Accelerated Protocol-2) cohort study. 7
The model's population characteristics were based on sample-size weighted averages from observational studies used to inform the clinical and state-transition parameters of the model ( Appendix 6 , ). 24 The population was 46 years old on average at the time of receiving their osseointegrated prosthetic implant and consisted of 70% males and 30% females. Clinical experts validated these characteristics as representative of the Canadian population (Nancy Dudek, MD; Richard Jenkinson, MD; Dan Mead, CP(c); Amanda Mayo, MD; John Murnaghan, MD; communications, August to November ). We also assumed everyone in the model had a unilateral above-the-knee amputation, which represented the majority of osseointegrated prosthetic implants and allowed us to standardize and simplify costing.
This model evaluated a population of individuals with a lower-limb amputation, not due to diabetes or severe vascular disease, with a medical history of issues related to the use of a conventional socket prosthesis that resulted in an uncomfortable prosthesis fit and difficulty walking. Additionally, patients had to meet distinct eligibility criteria specific to receiving the osseointegrated prosthetic implant, such as having reached full skeletal maturity, not currently undergoing chemotherapy, and not taking corticosteroid or immunosuppressant drugs. For the full list of clinical requirements, see Appendix 6 , .
We conducted a cost&#;utility analysis to determine the costs and health outcomes (i.e., quality-adjusted life-years [QALYs]) associated with each treatment strategy. We chose this type of analysis because utility inputs are available and a generic outcome measure such as QALYs allows decision-makers to make comparisons across different conditions and interventions. The outcomes reported are total costs and total QALYs for each treatment, and incremental cost per QALY gained compared to the next most effective strategy. For this analysis, incremental costs and QALYs are key outcomes considered by decision-makers, while total costs and QALYs of treatment options are informative measures for decision-makers.
We conducted a reference case analysis and sensitivity analyses. Our reference case analysis adhered to the Canadian Agency for Drugs and Technologies in Health (CADTH) guidelines when appropriate and represents the analysis with the most likely set of input parameters and model assumptions. 47 Our sensitivity analyses explored how the results are affected by varying input parameters and model assumptions.
presents the results of all scenario analyses, previously described (see ). They show a wide range of ICER values based on variations in model inputs and model assumptions. At a willingness-to-pay value of $100,000 per QALY, the probability of osseointegrated prosthetic implants being cost-effective in the reasonable best scenario was 92.2% and in the reasonable worst scenario was 35.1%.
presents the results of the one-way sensitivity analyses through a tornado diagram. The ICER was highly sensitive to five variables: the utilities for osseointegrated prosthesis and uncomfortable socket prosthesis, time horizon, implant extraction rate, and stump revision rate. When the utility input for the &#;osseointegrated prosthesis&#; health state (reference case = 0.692) was set at 0.726 (high estimate), the ICER dropped to $51,620 per QALY gained, but rose to $653,555 per QALY gained if the utility input was 0.658 (low estimate). When the model time horizon dropped below a lifetime horizon to only 5 years, the ICER rose to a peak of $265,581 per QALY gained. As the probability of implant extraction rose to 0., the ICER increased to $154,899 per QALY gained, but if the implant extraction rate dropped to 0. the resulting ICER was $78,062 per QALY gained. Finally, if the stump revision rate in socket prosthesis users increased to 0.186 (a rate similar to the soft-tissue refashioning in the osseointegration cohort) the ICER dropped to $57,076 per QALY gained.
The cost-effectiveness acceptability curve presented in shows the probability of both interventions (osseointegrated prosthetic implants and uncomfortable socket prostheses) being cost-effective across a range of willingness-to-pay values. At a willingness-to-pay value of $100,000 per QALY, the probability of osseointegrated prosthetic implants being cost-effective was 54.17%. As the willingness-to-pay value crossed $40,000 per QALY and continued to rise, the probability of implants (the more costly strategy) being cost-effective also rose. Appendix 6 , , presents an incremental cost-effectiveness scatterplot for the reference case results.
presents results from the reference case analysis. Over a lifetime horizon, the osseointegration cohort had an average total cost of $101,166 and 19.12 QALYs per person. Compared with an uncomfortable socket prosthesis, an osseointegrated prosthetic implant has an incremental cost of $84,559 and an incremental effect of 0.890 QALYs. The reference case ICER for an osseointegrated prosthetic implant compared with an uncomfortable socket prosthesis is $94,987 per QALY gained.
The results of the analysis indicated that, in eligible patients, an osseointegrated prosthetic implant is more costly and more effective than continuing to use an uncomfortable socket prosthesis. The reference case analysis showed osseointegrated prosthetic implants, when compared to an uncomfortable socket prosthesis, had an ICER of $94,987 per QALY gained, which corresponds to a 54.2% probability of being cost-effective at a willingness-to-pay value of $100,000 per QALY. As willingness-to-pay values increased, the probability of implants being cost-effective increased to 74.2% at $150,000 per QALY.
However, sensitivity analyses indicated these results were largely influenced by both parameter uncertainty and key assumptions. One input to note is the probability of stump revisions in the uncomfortable socket cohort. This was the only complication evaluated for the socket cohort in our model, and given a lack of evidence in the published literature, we used a probability estimate taken from hospital data from a previous cost&#;utility analysis for our reference case.45 This probability estimate was the lowest complication in the model (0.026) and was slightly less common than infrequent complications in the osseointegration cohort such as fractures (0.027) and deep infections (0.033). The reference case estimate may be conservative, given that stump revisions often treat a wide variety of conditions related to an uncomfortable socket prosthesis, such as bone spikes, soft tissue&#;socket interface problems, neuromas, and infections.58 A one-way sensitivity tested this by increasing the probability to the same value as osseointegration's soft tissue refashioning (0.18), and the ICER decreased to $45,519 per QALY gained.
Osseointegrated prosthetic implants are a novel technology in Ontario, and estimating costs required that we use proxy values, validated by clinical experts. Owing to the uncertainty this creates, we designed the model's reference case to conservatively estimate the cost-effectiveness of osseointegration. For example, the reference case did not include the cost of prosthetist visits for prosthesis maintenance and adjustment, even though these costs appear to be a key driver of cost-effectiveness in osseointegrated prosthetic implants. This decision was due to a lack of data to inform the cost differences between cohorts. Ontario has not developed fee codes for prosthetist care for amputees using an osseointegrated prosthetic implant; instead, we calculated these fees using an hourly rate for clinical and technical prosthetist services, which is typically used for cases where there are modifications not listed; for billing, these services require approval from the ministry's Assistive Devices Program. Although a previous publication found that implant users visit a prosthetist less frequently than conventional socket users (7 vs. 3 visits per year), the cost of each visit was difficult to estimate as it is specific to the purpose of the visit.52 Based on expert feedback, we expected the average cost of a prosthetist appointment would be lower for implant users because the soft tissue&#;socket interface is eliminated (Dan Mead, CP(c), communication, August ). To estimate costs, we assumed each adjustment would take 1 hour for an implant user and 2 hours for a socket user (Nancy Dudek, MD, communication, August ). Despite published data on the number of maintenance visits, we excluded prosthetic maintenance fees from the reference case due to the uncertainty around the true cost difference between cohorts.
We used scenario analyses to test various model assumptions. Creating a &#;reasonable best scenario&#; and &#;reasonable worst scenario&#; helps to better understand how the model assumptions and variability of the inputs impact cost-effectiveness when combined. Both best and worst reasonable scenarios excluded changes to the time horizon, discount rate, and utilities, and instead focused on other &#;reasonable&#; inputs. These analyses excluded alternative utility values from Branemark et al10 and Hagberg et al13 because those studies mapped health-related quality of life scores to derive utilities, specifically from mean SF-36 domain scores to SF-6D utility values. This technique, although useful if there are data limitations, is less precise and accurate than utility values directly elicited from a SF-6D questionnaire.
The ICER obtained from the reasonable best scenario was heavily influenced by the inclusion of prosthetist maintenance costs and time-varying complication rates. Unlike in the reference case, the reasonable best scenario used time-varying rates from a single study, instead of an average weighted rate from multiple studies. In that single study, no cases of soft tissue refashioning occurred, and there were no cases of deep infection after the first year. When modelling the time-varying complication rates, we used the event rate in the second year (zero) for all subsequent years. As there would be no cases of deep infection after the first year, compared to the reference case this approach would underestimate the costs of deep infections over a lifetime horizon. Based on these limitations, we did not use time-varying complication rates in the reference case. However, the single study informing these rates does suggest that rates of superficial and deep infection are lower in the second year after osseointegration surgery.10 If complication rates do decrease after the first year, our reference case model with its constant rates may overestimate the occurrence and costs of complications over a patient's lifetime. Other inputs used in the reasonable best scenario include a reduction in the device cost for osseointegrated prosthetic implants, as the cost in the reference case was based on a cost reported by a surgeon performing a single surgery. As previously discussed, another input, single-stage vs. two-stage osseointegration surgery, is a newer development that could reduce operating room costs but as yet has no published evidence to inform its effectiveness and complication rates.
The reasonable worst scenario included two key inputs that were excluded from the reference case due to insufficient evidence to properly inform their estimates. The first, the inclusion of mechanical part replacement, was derived from studies that did not specify the implant parts that required replacement, so we conservatively assumed that all external parts were replaced. The second, the inclusion of disutility values for complications (i.e., fractures and deep infections), was not specific to lower-limb amputees and was based on values from instruments other than the model's SF-6D values (i.e., EuroQol 5-Dimension [EQ-5D] and Assessment of Quality of Life [AQoL]). Further research is needed to refine these important model inputs, which influence the cost-effectiveness of osseointegrated prosthetic implants for lower-limb amputees.
In our economic evaluation, we assessed osseointegrated prosthetic implants as a therapeutic class to inform recommendations about public funding the intervention. We did not differentiate between manufacturers, primarily due to a lack of manufacturer-specific data that could inform all model inputs. However, it should be noted that the majority of publications used to inform this analysis were from the OPRA and ILP systems. There is uncertainty around whether the longevity of the implant differs among the systems currently available and around whether implant design leads to different challenges in the event of surgical removal and reimplantation.
The model assumed that rehabilitation of patients undergoing osseointegration surgery took place in an inpatient setting. Despite costing more than care in an outpatient setting, an inpatient rehabilitation stay likely best represents both the clinical and Ontario health care context. A lengthy, intensive rehabilitation process is required as patients progress through a gradual, stepped approach to weight-bearing on the prosthetic limb.29 Clinical experts indicated that, if the program is implemented, it should be restricted to a select number of specialty health centres with interdisciplinary teams of surgeons, physiatrists, nurses, and physiotherapists. This approach would promote optimal surgical performance by ensuring surgeons receive an adequate annual volume of osseointegration surgeries (Wade Gofton, MD, communication, August ). Given this advice, we assumed that patients from across the province would travel to these centres to receive care and that a lengthy outpatient rehabilitation would be a burden to all but those living nearby. Inpatient rehabilitation was also anticipated so that wound care and medications could be actively managed by nursing staff after surgery and into early rehabilitation (Nancy Dudek, MD, communication, August ).
To simplify economic costing, this model assumed external components were similar for socket and osseointegrated prostheses. Therefore, incremental costs and utility gains attributed to these components were excluded from the analysis. If future data become available, this assumption should be tested further, because another analysis by Haggstrom et al52 suggested that osseointegrated prostheses may be more costly due to the use of more advanced prosthetic components (e.g., microprocessor knees).
We did not use a societal perspective in this analysis due to insufficient data on the target population. However, osseointegrated prosthetic implants may provide unique benefits, such as allowing a person to go back to work and no longer require disability support because their mobility has improved, which may lead to financial savings from a societal perspective.
Our study had distinct differences from two previous cost-effectiveness analyses. The first, by Frossard et al,44 found an ICER of $16,632 per QALY gained, but the study only included prosthetic costs from a dataset at a single prosthetic facility. Specifically, it did not include costs of surgery, rehabilitation, and complications. The authors used utility values similar to those in our reference case, but the overall QALY calculation was simplified as they used neither a Markov model nor other forms of decision-modelling. As the study pulled costs from their real-world dataset, the time horizon was only 6 years to reflect the length of follow-up in the dataset.
Hansson et al45 found an ICER of &#;83,374 per QALY gained, and based their complications and health state transitions primarily on a single study by Branemark et al.10 This ICER was higher than what was reported in our reference case, but this difference is likely due to the 20-year time horizon, as our scenario with that time horizon found a similar ICER of $123,112 per QALY gained. The authors stated that they chose this time horizon for their reference case as the technology is relatively new and they are uncertain how long patients will benefit from it. However, they do report being aware of 8 patients from previous studies who have passed 15 years of follow-up.45 The cost-effectiveness analysis by Hansson et al45 was similar to our work in that their model was sensitive to changes in the interventions' utility values, and we both used similar utility values and clinical complications. Of note, both Frossard et al44 and Hansson et al45 differed from our analysis in that they did not use discounting, with one stating that costs were not discounted because the majority of costs occurred in the first and third years, when prosthetic knees and feet were supplied.44
Our primary economic evaluation has several strengths. It is the first analysis to estimate the economic value in Canada of osseointegrated prosthetic implants for eligible lower-limb amputees. The study used Ontario-specific costs wherever possible, and Canadian costs for the implant system. Our analysis is also the first to include disutilities for complications related to the osseointegration surgery and implant (deep infections and fractures), as well as other analyses such as time-varying rates to inform event transitions. Another strength is the use of pooled rates for health-state transitions and complications to capture parameter variability across the published literature. Additionally, cost estimates were informed by a multidisciplinary team of medical professionals involved in the care pathway, including surgeons, physiatrists, physiotherapists, and prosthetists.
Our analysis also has limitations. As the osseointegration procedure is not currently being conducted in Ontario, the Schedule of Benefits has no physician fee codes to inform precise estimates of surgical costs and inpatient stays. In the absence of costing data, we used proxies validated by clinical experts. We also used simplifying assumptions in the absence of established clinical practices in Ontario for patients with osseointegrated prosthetic implants. There are potential areas for additional costs that we did not evaluate, such as additional prosthetist adjustments after femoral fractures in implant users or prosthetic adjustments to alter socket fit following stump revisions in conventional prosthesis users. As described earlier, the data on users of uncomfortable socket prostheses are limited. As a result, we could not cost additional issues identified by experts: scar revisions, wound care, superficial infections, material and suspension system costs for prosthetist socket adjustment and replacement, and (if we included a societal perspective) out-of-pocket costs for antibiotics, antifungals, and dressing supplies (Nancy Dudek, MD; Wade Gofton, MD; communications, November ). Another potential limitation is the applicability of the literature to our comparator: patients with an uncomfortable socket prosthesis. Previously published literature did not always specify the comparator in this way, so these studies may include patients with a comfortable socket fit and a preference to switch to an osseointegrated prosthetic implant. Therefore, given the pre-post study design commonly used in this literature, the rates of complications in our uncomfortable socket cohort may have been higher if we were able to strictly enforce this population in our model inputs.
In , Congress appropriated $15,000 for the purchase of artificial limbs for soldiers and seamen disabled in the service of the United States, to be expended under the direction of the Surgeon General of the United States.
In , the War Department (now the Department of Defense) was authorized to provide Union Veterans with transportation to and from their homes to a place where they could obtain their artificial limbs or devices, and to furnish those Veterans with new artificial limbs or devices every five years.
VA's involvement in providing prostheses to Veterans began in , when the Veterans Bureau, a predecessor agency to the Department of Veterans Affairs, was given the responsibility to provide artificial limbs and appliances to World War I Veterans.
Today, VA's Prosthetics and Sensory Aids Service is the largest and most comprehensive provider of prosthetic devices and sensory aids in the world. Although the term "prosthetic device" may suggest images of artificial limbs, it actually refers to any device that supports or replaces a body part or function.
VA provides a full range of equipment and services to Veterans, ranging from items worn by the Veteran, such as artificial limbs and hearing aids; to those that improve accessibility, such as ramps and vehicle modifications; to devices surgically placed in the Veteran, such as hips and pacemakers.
The department has more than 70 locations at which orthotics and prosthetics are custom-fabricated and fitted, using state-of-the-art componentry. A list of VA orthotic and prosthetic providers can be found here. VA also has more than 600 contracts with accredited orthotic and prosthetic providers to ensure access to care is provided near Veterans' homes. Each VA facility that is eligible for certification is accredited through the American Board for Certification in Orthotics, Prosthetics & Pedorthics (ABC) and/or the Board of Certification/Accreditation (BOC).
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To help meet the lifestyle and medical needs of Veterans who have lost limbs, VA researchers develop and test a wide variety of prosthetic devices. VA's goal is to offer Veterans prosthetics that will restore them to their highest possible level of functioning within their families, communities, and workplaces.
Some VA researchers are working on developing high-functioning artificial limbs that are very similar to their natural counterparts. Others are working on advanced wheelchair designs that promote mobility and independence for wheelchair users and make it easier to use a wheelchair.
Still other VA researchers are using functional electrical stimulation and other technologies to help those with weak or paralyzed muscles, and developing and testing state-of-the-art adaptive devices to help those with vision or hearing loss.
If you are interested in learning about joining a VA-sponsored clinical trial, visit our research study information page.
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Many, but not all, of the latest innovations and discoveries in prosthetics research in the U.S. take place at VA centers. These centers generally work in close partnership with affiliated universities and other institutions, as well as commercial partners and other federal agencies.
VA's Advanced Platform Technology Center, in Cleveland, develops new technologies to help Veterans who have difficulties controlling bodily movements or sensory problems, and those who have lost limbs. Team members create new assistive and restorative technologies for dissemination within the rehabilitation community and commercialization by outside manufacturers.
The Center for Functional Electrical Stimulation, also in Cleveland, uses controlled electrical currents to help paralyzed muscles work again. The center focuses on the application of electrical currents to either generate or suppress activity in the nervous system. This technique is known as functional electrical stimulation (FES). FES can produce and control the movement of otherwise paralyzed limbs for standing and hand grasp, to activate visceral bodily functions such as bladder control or respiration, create perceptions such as skin sensibility, stop undesired activity such as pain or spasm, and facilitate natural recovery and accelerate motor relearning.
The Center for Wheelchairs and Associated Rehabilitation Engineering, part of the Human Engineering Research Laboratories (HERL) in Pittsburgh, has made important contributions to the design of wheelchairs, seating systems, and other mobility systems. HERL is a collaboration between the VA Pittsburgh Healthcare System and the University of Pittsburgh. Researchers at the center have been instrumental in developing novel innovations in wheelchair design&#;together, they hold 25 patents related to wheelchair design and assistive technologies. Innovations developed at the center range from using newer, lighter materials that make wheelchairs easier to maneuver to robotic extensions that can reach objects for the wheelchair's user. One example under development is the MEBot, a wheelchair that has six wheels, an onboard computer and software, and an array of high-tech sensors and actuators that help the user navigate uneven terrain.
The Center for Limb Loss and MoBility in Seattle is a research group focused on helping Veterans who have either lost a limb or experience leg and/or foot impairment by enhancing their ability to move around their environment. Research at the center aims to reduce the effects of functional and anatomical limb loss by exploring diseases that lead to impaired limb function and by developing state-of-the-art technologies for studying the foot. Research focuses on two groups of Veteran: those with musculoskeletal impairment at the foot and ankle, where pain and limitations in mobility are the key issues, and those at risk of lower limb amputation due to diabetes and foot ulceration, where loss of the foot or leg is a major concern.
The center's prosthetic engineering research focuses on limitations in mobility and discomfort experienced by all groups of Veterans with lower-limb amputation&#;including those with amputation secondary to peripheral vascular disease and diabetes; aging combat-injured Vietnam Veterans; and young, active Veterans who lost a limb through traumatic injury serving in Afghanistan or Iraq. This research compares existing prosthetic technologies and develops innovative new approaches.
The VA Center for Neurorestoration and Neurotechnology in Providence, Rhode Island, supports research into the development of brain-computer interfaces to help restore function in Veterans who are paralyzed, have experienced limb loss, or have difficulties in thinking or communicating. The center is a collaboration between the Providence VA Medical Center, Brown University, Butler Hospital, Lifespan, and Massachusetts General Hospital. CfNN seeks to develop, test, and implement new therapies and technologies that restore function for Veterans with disorders affecting the nervous system.
BrainGate is one such research project. Researchers have developed a neural interface system for individuals with paralysis that uses a small sensor implanted in the brain to record neural activity associated with intended arm movements.
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The technology involved in creating artificial limbs has come a very long way since the Civil War. Today's VA researchers use leading-edge technologies such as robots and nanotechnology to create lighter limbs that integrate body, mind, and machine to look, feel, and respond like real arms and legs. They are also studying ways to best match prosthetic components with amputees' needs, including those whose active lifestyles mean they need high-performance prosthetics.
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Other researchers are looking at new ways to care for what remains of limbs after surgery; enabling wounds to heal far more quickly than ever before; developing programs to teach caregivers complementary and alternative techniques to lessen the anxiety and pain associated with limb loss; and evaluating CT scans of diabetic feet to identify those patients who are at the highest risk for ulcers and amputation.
Ankle-foot prosthesis&#;In , VA collaborated with researchers at MIT and Brown University to introduce a powered ankle-foot prosthesis that uses tendon-like springs and an electric motor to move users forward. Studies have shown that patients using the powered ankle-foot expend less energy while walking, have better balance, and walk 15 percent faster. The device, originally sold as the BiOM ankle and now marketed as the Empower ankle, is available for Veterans using VA care and active-duty service members.
Osseointegration study&#;VA sponsored the first human study in the United States to investigate osseointegrated prosthetics, a system that allows a prosthetic limb to be attached through the skin directly to the remaining bone of the amputated limb. The study involved surgically implanting specially designed and coated titanium implants into the thigh bone of amputees who had lost their knee and lower leg. Once the bone grew into the implant, the prosthesis was attached directly to the metal connector of the implant without the need for a prosthetic socket to cover the remaining limb.
Ten amputees participated in the study at the George E. Wahlen VA Medical Center in Salt Lake City. Based on preliminary findings, the investigators say this research has the potential to improve amputees' mobility, function, and overall quality of life. A version of this implant for above-the-elbow amputees is currently in development.
DEKA/LUKE arm&#;VA researchers and colleagues collected data on the DEKA advanced prosthetic arm over four years at four VA sites&#;New York; Tampa; Long Beach, California; and Providence, Rhode Island&#;and at the Center for the Intrepid, a military rehabilitation site in San Antonio, Texas. The study findings have been published in a number of journal articles, including two in in VA's Journal of Rehabilitation Research and Development.
The arm was developed by DEKA Integrated Solutions Corporation, based in Manchester, New Hampshire, with funding from the Defense Advanced Research Projects Agency (DARPA), through its Revolutionizing Prosthetics Program. It is the first prosthetic arm capable of performing multiple simultaneous powered movements.
The U.S. Food and Drug Administration approved the DEKA Arm System in May , paving the way for the device to be manufactured, marketed, and made available in the VA health care system. The DEKA arm is now available to the public as the LUKE arm, manufactured by Mobius Bionics.
In a study led by researchers from the Providence VA Medical Center and Brown University, 24 upper-limb amputees were fitted with a second generation (Gen 2) DEKA arm, and 13 were fitted with a third-generation arm (Gen 3). After being trained on its use, they were surveyed about their experiences.
In all, 79 percent of Gen 2 and 85 percent of Gen 3 users indicated that they either wanted to receive, or might want to receive, a DEKA arm. In addition, 95 percent of Gen 2 users and 91 percent of Gen 3 users indicated that they were able to perform new activities they had been unable to perform with their existing prosthetic device.
In July , two Veterans became the first VA patients to receive the arm for daily use.
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In , approximately 130,428 Veterans in the U.S. were legally blind and more than 1 million Veterans had low vision that caused a loss of ability to perform daily activities, according to VA's Blind Rehabilitation Service.
Those figures are expected to increase as more Veterans from the Korean and Vietnam conflict eras develop vision loss from age-related diseases such as macular degeneration, diabetic retinopathy, and glaucoma. VA has also seen an increase in the number of Veterans who served in Afghanistan and Iraq who have experienced vision loss due to blast exposure and trauma.
In , VA researchers introduced the first mobility and orientation rehabilitation training program for blind persons. Today, VA's Center for Visual and Neurocognitive Rehabilitation, based at the Atlanta VA Health Care System, conducts research in visual rehabilitation, neurocognitive rehabilitation (i.e., improving brain function from injury), and retinal and neural repair to prevent and mitigate vision loss resulting from injury or disease. The center has a number of projects to help train blind people and those with low vision find their way around independently with greater ease. Investigators also work on projects related to improving access to eye care for Veterans living in rural regions.
Examples of projects include: "Bridging Animal and Human Models of Exercise-Induced Visual Rehabilitation," "Spatial Cognitive Training in Visual Impairment," "Acute Exercise Effects on Word Learning in Aging and Stroke-induced Aphasia," "Improving Access to Eye Care for Veterans&#;Spread Grant; VA Innovation Initiative," and "Dopamine Treatments for Diabetic Retinopathy."
In addition, the VA's Center for Prevention and Treatment of Visual Loss focuses on research to provide the earliest detection of vision loss. The goal is to prevent vision loss due to eye diseases such as glaucoma, radiation damage, and traumatic brain injury. The center is evaluating new diagnostic tools that provide better access to care through telemedicine and automated analysis using portable devices by non-eye care providers. Research is focused on novel interventions such as identifying which neurotrophic growth factors (i.e., proteins associated with growth and survival of neurons) are most effective at preventing vision loss.
Examples of projects include: "Therapy of Nocturnal Intraocular Pressure Elevation Causing Glaucoma Progression," "Automated Assessment of Optic Nerve Edema with Low-Cost Imaging," "Chronic Effects of Blast Injury: Analyses of Alzheimer Related Pathology," "Stem Cell Therapy for Glaucoma," and "Visual Sensory Impairments and Progression Following Mild Traumatic Bain Injury."
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Many Veterans have serious spinal cord injuries and disorders that may interfere with the brain signals that control muscle movement. Others have become blind from the loss of photoreceptors (cells that are responsible for detecting light and therefore enable us to see) in the eye.
For Veterans with these and some other types of functional loss, VA investigators hope to restore functioning with electrical currents delivered through a neural prosthesis. A neural prosthesis is an electronic device that connects with the nervous system and supplements or replaces functions lost by diseases or injury.
VA's Advanced Platform Technology Center (APT), located at the Cleveland VA Medical Center, and the Center for Neurorestoration and Neurotechnology at the Providence VA Medical Center are working on a number of projects to extract signals from the brain's cortex for controlling assistive devices and detecting and diagnosing dysfunctional cortical activity. Some of their projects are described here and here.
Conveying a sense of touch&#;Researchers at the Advanced Platform Technology Center have developed a new kind of implanted electrical nerve interface that can convey a sense of touch on a prosthetic hand. They learned in that the implants continued to work after 24 months, and as of this writing they continue to work.
Sensors in the prosthetic hand measure the pressure applied as the hand closes around or presses against something. These measurements are converted into specially coded electrical signals and sent through wires to surgically implanted electrodes around nerves in the forearm and upper arm.
When the electrical signals reach the nerves, they are transmitted to the brain through healthy neural pathways not affected by the amputation. The brain interprets the sensation signals as if they had come from a normal hand. These researchers have since been funded by DARPA to further advance the work. Watch this video to learn more.
Electrical stimulation and spinal cord injuries&#;In , researchers at VA's APT Center and Case Western Reserve University completed a 10-year clinical trial to test a surgically implanted electrical stimulation system in people with spinal cord injuries. During the surgery, electrodes are implanted in muscles of the trunk and legs, and leads are connected to a stimulator.
By stimulating muscles, the system activates muscles to allow for standing, better balance, and exercise. Patients are given functional training and rehabilitation using the stimulation system, and are prescribed a course of exercise. Lab tests focus on strength, balance, and patients' abilities with or without the system.
In , researchers in Cleveland followed up on 22 spinal cord-injured patients an average of six years after they received implantation surgery, to determine whether the devices were still functioning and useful years after they were first implanted.
They found that 60 percent of the patients still used their neuroprostheses for exercise and other activities for more than 10 minutes per day. Early (first generation) implants still functioned correctly in almost 90 percent of the recipients of those devices. Second-generation implants, with slightly improved technology, still functioned in 98 percent of recipients. Overall, 94 percent of the participants in the study were satisfied with their prostheses.
In another study, Cleveland researchersfound that a lower-limb exoskeleton that combined an implanted neurosensor with an exoskeleton to stabilize and support users restored the ability to take steps in three individuals with complete paralysis. They believe that this approach is feasible for individuals with paraplegia and should be developed further.
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VA has played a major role in supporting the development of BrainGate. The system, spearheaded by researchers at the Providence VA Medical Center in Rhode Island and Brown University, relies on microelectrodes implanted in the brain to pick up neural signals.
The electrodes are placed in a part of the brain that controls voluntary movement. They send signals to an external decoder that translates them into commands for electronic or robotic devices, such as an iPad or robotic arm.
The research team developing BrainGate hopes to create a technology that will restore movement, control, and independence to people with paralysis or limb loss from conditions including amyotrophic lateral sclerosis (ALS), stroke, and spinal cord injury.
BrainGate studies&#;In , a research team consisting of VA, Brown University, Harvard University, and Massachusetts General Hospital researchers successfully implanted electrodes in the brains of volunteers with paralysis affecting their arms and legs. The system allowed them to control robot arms with their thoughts, and they could continue to control a computer cursor accurately more than 1,000 days after the electrodes were initially implanted.
In , the BrainGate team reported the system could allow point-and-click communication by someone with incomplete locked-in syndrome, which can be caused by a spinal cord injury. In locked-in syndrome, patients are fully conscious but unable to move any muscles except for those that control eye movement. They can see, hear, smell, taste, and even feel, but may be unable to speak or vocalize at all. Those with incomplete locked-in syndrome can make small movements of the head, fingers, and toes.
Another BrainGate study found that volunteers using the system were able to acquire "targets" on a computer screen, such as letters on a keyboard, more than twice as quickly as in previous studies, thanks to advances in the system.
The BrainGate team is now studying whether the system can be effective as a means of natural, intuitive control of prosthetic limbs, or as a way to help patients move their own paralyzed limbs. The latter work is being carried out in partnership with the Cleveland FES Center.
A proof-of-concept study demonstrated that this combination of FES and BrainGate was successful in a quadriplegic Navy Veteran, who used electrodes implanted in his brain and in the muscles of his paralyzed arm and hand to use his own thoughts to control his arm and hand. This video shows how the system works, and how it offers potential help to people with paralysis in the future. The BrainGate team is currently working on the next generation of their system that will be fully implanted and wireless so it can be used at home without the assistance of a technician.
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Age and knee replacement&#;In , researchers at the Iowa City VA Health System and the University of Iowa looked at whether knee replacement (total knee arthroplasty) is safe for Veterans aged 85 or older.
The researchers combined and analyzed data from 22 past studies to see whether they could make a determination on the risks and benefits of the procedure for older patients.
They found that while the available evidence suggested slight increases in mortality and complications for older patients, several of the studies reported that both older and younger patients were highly satisfied after surgery, and were able to function better.
The team therefore concluded that age alone should not rule out such surgery.
Hip and knee replacement not followed by increased physical activity&#;In , a researcher with the Durham VA Medical Center and others published a literature review of previous studies that found that while patients often have large reductions in pain and increased physical function and quality life after total hip or knee replacement, there were no corresponding increases in physical activity after six months, and only modest increases after a year. The researchers hypothesized that the lack of physical activity may be behavioral, since a sedentary lifestyle is hard to change.
Racial gaps in use of knee replacements&#;African American patients shown an informational video about knee replacement surgery were 85 percent more likely to undergo the surgery than those who did not view the video, according to a study conducted by researchers at the Corporal Michael J. Crescenz VA Medical Center in Philadelphia.
According to the researchers, African Americans are significantly less likely to have knee replacement surgery to relieve pain from arthritis, largely due to lack of knowledge about the treatment. The researchers concluded that this low-cost, patient-centered intervention could increase the use of an effective orthopedic procedure among minority patients.
A study by VA researchers also found that African American Veterans were less likely to undergo knee replacement surgery. Over a 10-year period, rates of knee replacements were much lower for black Veterans than white Veterans. Hispanic Veterans had the same rates of knee replacement as white Veterans. The researchers stated that the study shows the importance of developing ways to reduce racial differences in Veteran health care usage.
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MEBot robotic wheelchair&#;HERL is developing a robotic wheelchair called MEBot that can go up and down curbs and steps and maintain a level seat over uneven terrain&#;giving Veterans who use wheelchairs for mobility unprecedented freedom and independence both outdoors and inside homes, shops, and offices. The wheelchair has traction control; anti-skid braking; and powered seat functions, including tilt, recline, leg-rest, and elevation.
It has six wheels, an onboard computer and software, and an array of high-tech sensors and actuators. It is designed to navigate smoothly over gravelly or muddy roads, uneven slopes, wet grass, and other difficult terrain&#;and should allow users to avoid getting stuck on snow and ice.
The MEBot is now being tested at the center's lab, and may be commercially available within a few years. In , the MEBot won "Best New Concept" in the Blackwood Design Awards competition in Scotland, an international competition that seeks to discover and recognize brilliant innovations in independent living and accessibility. Watch a video of the MEBot here.
Waterproof, motorized wheelchair&#;Researchers at HERL have also developed the PneuChair, a motorized wheelchair that uses a tank of compressed air instead of batteries as an energy source. The chair weighs about 80 pounds and takes just 10 minutes to recharge. The PneuChair can go about 3 miles before the tank must be charged again&#;about one the third the distance that an electronic wheelchair can go on a fully charged battery. It was developed, in part, to be used at a water park for people with disabilities, but could also be used at beaches or pools. The design is simpler than an electronic wheelchair&#;lacking much of the software and electronics that are typically used for motorized chairs.
Improved standing wheelchair&#;In , a group at the Minneapolis VA Medical Center reported they had made improvements to the traditional standing wheelchair to help improve the ability of paralyzed Veterans to function. The researchers modified commercially available standing wheelchairs by adding a drive wheel that allows the push rim to rise so patients can reach it when they stand.
In existing models, patients who can't reach the push rim in the standing position are forced to sit before they can boost the chair and move themselves to a new location. The new chair, which is not yet available commercially, also keeps at least four of the chair's six wheels on the ground at all time, increasing both stability and maneuverability.
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VA's Center on the Medical Consequences of Spinal Cord Injury is located at the James J. Peters VA Medical Center in the Bronx, New York. The center's mission is to improve Veterans' quality of life and increase their longevity by preventing and intervening in the secondary medical consequences that result from having a spinal cord injury. These consequences can include bone and muscle loss, and metabolic and cardiovascular changes.
Researchers at the center continue to study an Israeli technology that allows people with paralysis to stand, walk, and climb stairs, called ReWalk. ReWalk 6.0 is a wearable robotic exoskeleton that provides powered hip and knee motion to enable individuals with spinal cord injury to stand upright, walk, and turn. On their first day using the device, most people can stand and take a few steps, although it takes practice and training to use it properly.
Participants in past studies have lost fat tissue, their bowel function has improved, and their diabetes symptoms have been reduced. The center is now conducting a further trial on ReWalk's impact on mobility, bowel function, and cardio-metabolic health. The four-year study, involving 160 paralyzed Veterans with spinal cord injury at 10 VA medical centers, is examining the impact of the robotic exoskeleton on home and everyday life. Enrollment is expected to be completed in August .
In , ReWalk version 6.0 was approved for sale in the United States. In , VA announced it would provide the device to eligible Veterans who could benefit from it.
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Dentures can bring back the smile of those who have lost teeth because of aging, injury, and disease. Many denture wearers, however, must cope with a condition called dental stomatitis (thrush), in which the gums under the denture become sore and inflamed due to infection from a fungus known as candida.
VA researchers at the South Texas VA Health Care System are developing a new type of denture that fights stomatitis. The denture releases, over time, a drug that kills the candida fungus. In lab tests whose results were published in , the experimental product showed strong action against candida for up to 30 days, after which the device can be recharged with a fresh dose of drugs. More testing will be required, including a clinical trial, before the product is commercially available.
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Changes in physical activity after total hip or knee arthroplasty: a systematic review and meta-analysis of 6 and 12 month outcomes. Hammett T, Simonian A, Austin M, Butler R, Allen KD, Ledbetter L, Goode AP. Physical activity did not change at six months, and a small to moderate improvement was found at 12 months post-surgery, despite large improvements in quality of life, pain, and physical function. Arthritis Care Res (Hoboken). Jun;70(6):892-901.
Long-term performance and user satisfaction with implanted neuroprostheses for upright mobility after paraplegia: 2- to 14-year follow up. Triolo RJ, Bailey SN, Fogiyano KM, Kobetic R, Lombardo LM, Miller ME, Pinault G. Implanted lower-limb neuroprostheses can provide lasting benefits that recipients value. Arch Phys Med Rehabil. Feb;99(2):289-298.
Systematic review of measures of impairment and activity limitation for persons with upper limb trauma and amputation. Resnik L, Borgia M, Silver B. Cancio J. Few performance measures were recommended for patients with limb trauma and amputation. Arch Phys Med Rehabil. Sep;98(9):-.
Racial and ethnic differences in total knee arthroplasty in the Veterans Affairs health care system, -. Hausmann LRM, Brandt CA, Carroll CM, Fenton BT, Ibrahim SA, Becker WC, Burgess DJ, Wandner LD, Bair MJ, Goulet JL. Black-white differences in total knee arthroplasty appear to be persistent in VA, even after controlling for potential clinical cofounders. Arthritis Care Res (Hoboken). Aug;69:-.
A muscle-driven approach to restore stepping with an exoskeleton for individuals with paraplegia. Chang SR, Nandor MJ, Li L, Kobetic R, Foglyano KM, Schnellenberger JR, Audu ML, Pinault G, Quinn RD, Triolo RJ. A self-contained muscle-driven exoskeleton is a feasible intervention to restore stepping in individuals with paraplegia due to spinal cord injury. J Neurogen Rehabil. May 30:14(1):48.
Restoration of reaching and grasping movements through brain-controlled muscle stimulation in a person with tetraplegia: a proof-of-concept demonstration. Ajiboye AB, Willett FR, Young DR, Memberg WD, Murphy BA, Miller JP, Walter BL, Sweet JA, Hoyen HA, Keith MW, Peckham PH, Simeral JD, Donoghue JP, Hochberg LR, Kirsch RF. A report on an individual with high-cervical spinal cord injury who coordinated reaching and grasping movements using his own paralyzed arm and hand through implanted functional electrical stimulation and an intracortical brain-computer interface. Lancet. May 6;389():-.
Effect of a decision aid on access to total knee replacement for black patients with osteoarthritis of the knee: a randomized clinical trial. Ibrahim SA, Blum M, Lee GC, Mooar P, Medvedeva E, Collier A, Richardson D. A decision aid increased rates of total knee replacement among black patients. JAMA Surg. Jan 18;152(1);e.
Starting a new conversation: engaging Veterans with spinal cord injuries in discussion of what function means to them, the barriers/facilitators they encounter, and the adaptations they use to optimize function. Hill JN, Balbale S, Lones K, LaVela SL. Patients with spinal cord injuries highlight the concept of "normality," facilitators and barriers to function, and adaptations to optimize function. Disabil Health J. Jan:10(1):114-122.
Pilot testing of a variable stiffness transverse plane adapter for lower limb amputees. Pew C, Klute GK. A transverse rotation adapter with variable stiffness capability could be useful to help reduce stresses for a lower-limb amputee that result in soft tissue breakdown and discomfort. Gait Posture. Jan;51:104-108.
Proposed pedestrian pathway roughness thresholds to ensure safety and comfort for wheelchair users. Duvall J, Sinagra E, Cooper R, Pearlman J. Many public pathways are sufficiently rough to result in harmful vibrations and discomfort for wheelchair users. This study suggests a pathway roughness index threshold to protect wheelchair users against discomfort and possible health risks due to vibration exposure. Assist Technol. Sep 2:1-7. (Epub ahead of print)
Rechargeable anticandidal denture material with sustained release in saliva. Malakhov A, Wen J, Zhang BX, Wang H, Geng H, Chen XD, Sun Y, Yeh CK. A new denture material holds promise for long-term management of denture stomatitis. Oral Dis. Jul;22(5):391-8.
The effects of advanced age on primary total knee arthoplasty: a meta-analysis and systematic review. Kuperman EF, Schweizer M, Joy P, Gu X, Fang MM. Existing data supports offering total knee arthoplasty to select geriatric patients, although the risk of complications may be increased. BMC Geriatr. Feb 10;16:41.
Clinical translation of a high-performance neural prosthesis. Gilja V, Pandarinath C, Blabe CH, Nuyujukian P, Simeral JD, Sarma AA, Sorice BL, Perge JA, Jarosiewicz B, Hochberg LR, Shenoy KV, Henderson JM. Measured more than one year after implant, the BrainGate neural cursor-control system showed the highest published performance achieved by a person to date, more than double that of previous pilot clinical trial participants. Nat Med. Oct;21(10):-5.
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