Accidents Happen. Then What?
September 2017 Issue
Traumatic upper-limb amputation is a devastating event. The inadequacies of current prosthetic technologies, with their inherent bulk and heat retention, lack of sensory input, and limited dexterity, have been readily acknowledged by the O&P profession. However, comparing upper-limb prosthetic function against able-bodied function fails to provide the type of insight that might guide clinical decision making. Once traumatic amputation has occurred, able-bodied function is no longer an option. However, depending upon some variables, a few options may exist. In addition to revision amputation and prosthetic fitting, individuals may be candidates for either surgical reattachment or surgical transplantation. Recent years have seen the publication of several clinical reports and reviews addressing the relative function and psychological considerations associated with these three treatment options. This article reviews recent literature, beginning with a comparison between the prosthetic function experienced with an external prosthesis and that associated with hand transplantation, and concluding with observations comparing replantation with prosthetic rehabilitation.
In the introduction to their multicenter cohort study comparing the functional and psychosocial outcomes of hand transplantation against external upper-limb prostheses, Salminger et al. provide a succinct review of the history of hand transplant surgery.1 The first documented hand transplantation occurred in Ecuador in 1964. Unfortunately, the procedure was almost immediately unsuccessful and subsequent removal was required only two weeks later due to inadequate immunosuppressive therapy. The first successful transplant came over 30 years later in France and was performed on a transradial residual limb. The resultant limb remained viable for nearly two and a half years before it also had to be removed due to lapses in immunosuppressive medication. From then until 2014, 107 upper-limb transplantations were performed on 72 patients in 26 centers worldwide. Of these, roughly one quarter (n = 24) have since required surgical removal. In addition to the sizable risk of eventual rejection, the comorbid risks associated with immunosuppression, and the extensive post-surgical hand therapy represent further deterrents to the procedure.1
Interestingly, while rates vary from report to report, the abandonment rates of upper-limb prostheses approximate the physiologic rejection rates reported with hand transplantation. In prosthetic rehabilitation, the risks of immunosuppressive medications and extended hospitalizations are exchanged for the limitations of upper-limb prostheses, including limited control and dexterity, socket heat and pressures, and the lack of sensory input.
Salminger et al.'s multicenter trial reports upon five patients who underwent hand transplantations (two of whom received bilateral hand transplantations) and seven patients who underwent rehabilitation with unilateral, external myoelectric prostheses. Transplant patients were recruited from the Medical University of Innsbruck, Austria, and the Hand Transplant Center in Trzebnica, Poland. The prosthetics patients were managed through the Medical University of Vienna, Austria, and fitted with a range of Ottobock myoelectric hands including the Michelangelo hand (n = 2), the SensorHand Speed (n = 3), and the Transcarpal hand (n = 2). All myoelectric systems were controlled using conventional, dual-site direct control.1
Among those who had undergone hand transplantation, 5-12 years had lapsed between the surgery and evaluation, with an average span of nine years. The individuals with amputations were 1-9 years post-amputation at the time of the assessment, with an average of three years. Notably, all subjects reported high satisfaction with their prostheses, had declined hand transplantation because of the associated immunosuppressive medications, and wore their prostheses 8-16 hours per day.1
All subjects underwent the same battery of outcomes assessment, inclusive of the Action Research Arm Test (ARAT), the Southampton Hand Assessment Procedures (SHAP), and the Disabilities of the Arm, Shoulder and Hand (DASH), all measures of global upper-limb function (See sidebar, pg. 48). In addition, quality of life was assessed using the self-report Short Form 36 (SF-36) questionnaire, inclusive of four separate scales for physical and mental health.1
The mean scores for all three of the measures of upper-limb function were similar between the two groups, with no significant differences reported. Further, there were no noticeable differences between the two objective measures of upper-limb function, the ARAT and SHAP (Table 1).
While there were several areas on the SF-36 with similar congruence, including physical functioning, bodily pain, general health, and social functioning, there were domains where differences in psychosocial outcomes were observed. Because SF-36 scores are rated to normative population averages, some additional insights can be posited. For example, in the domain called role physical, the transplantation group reported average scores while several of the prosthesis users reported below average scores, a finding that diverges from the comparatively higher functionality (or decreased disability) reported by prosthetic users on the DASH relative to transplant patients.
It is noteworthy to observe that the differences in self-report assessments of function (physical functioning on the SF-36 and the DASH) were not supported by differences in performance measures (ARAT and SHAP), suggesting that deficits reported by prosthesis users and transplantation patients may be perceived more than experienced.1
In summary, when only objectively observed motor function is considered, there appears to be no difference in hand function between the two groups, and both solutions appeared to provide sufficient hand function for most necessary activities. For the authors of the study, these results underscore the importance of considering the additional risks associated with transplantation. If we accept the premise that patients should receive the treatment that is most beneficial with the least risk of harm, the equivalence in upper-limb functional scores may undermine the case for transplantation in some individuals.1
All the transplant subjects in the study had at least one (and as many as seven) acute episodes of rejection resulting in "nausea, headaches, fever and edema requiring hospitalization." Further, extended immunosuppression "increases the risk of infection, neoplasia, metabolic disorders, and organ failure." Collectively, the authors assert that "lifelong immunosuppression can be seen as a chronic disease…characterized by its own set of risks."1
The authors continue to suggest that the sensory benefits associated with transplantation should be weighed against the reality that among patients with unilateral injury, the sound limb will always be the more functional extremity, will ultimately become the dominant limb, and will perform the majority of the daily activities, while the transplanted hand will be a "helping hand." The benefits of sensory restoration in this application can be questioned.1
For bilaterally affected patients, the need for sensory restoration is more pronounced, with no sound limb to rely on for daily function, and may reasonably outweigh the risks of lifelong immunosuppression. Hence, bilateral transradial amputation is the most accepted indication for hand transplantation.1
Importantly, these conclusions and considerations will likely change with improvements to both prosthetic technologies and transplantation resources. Efforts continue to provide prosthetic sensory restoration, a paradigm shift that would radically alter users' perceptions of their prostheses and potentially allow patients to see their devices as an extension of themselves rather than tools attached to their bodies. Similarly, the study authors suggest that "the successful induction of donor-specific tolerance would prohibit the toxicity associated with non-specific immunosuppression and may therefore eliminate the risk of chronic rejection."1
Given that the largest deterrent to hand transplantation is the associated immunosuppressive medication therapies, it stands to reason that surgical replantation, whenever it is a viable option, should be attempted. Formal evaluation of this premise has also been undertaken.2-3
In a recent systematic review, Otto et al. aggregated the findings of some 301 replantation patients taken from 34 clinical trials. Efforts were made to compile findings related to function and patient satisfaction. As might be expected, the former consideration was more variable. Excellent function, for example, was only reported for 20 percent of the transradial subjects, with ratings of good and fair being more common at 30 and 32 percent respectively. Poor function was only indicated for 18 percent of the transradial group. Results were less compelling at the transhumeral level, with fair and poor function predominant, identified for 30 and 31 percent respectively, and excellent and good function reported for only 17 and 22 percent respectively.2
However, satisfaction data, reported for 191 of the aggregated subjects, was nearly uniform, with all but one replanted subject either satisfied or highly satisfied with their limb replantation.2 Restated, even when functionality is substantially compromised to the level of fair or even poor levels, patients are almost uniformly satisfied with the results.
Unfortunately, the nature of the aggregated data did not allow for an apples-to-apples comparison of patients managed with replantation versus prosthetic rehabilitation. The functional outcome and satisfaction metrics used in the replantation literature were not reported in the prosthetic literature. Rather, the authors chose to report a surrogate metric of function and satisfaction, summarizing prosthetic usage parameters. Usage, they theorized, would reflect both variables to some extent. As with the replantation subjects, usage rates improved at distal amputation levels, with 92 percent of 74 transradial amputees extracted from seven studies reporting full or limited use. As with replantation, outcomes at the transhumeral level were less encouraging, with only 49 percent of 82 subjects reporting full or limited use of their prostheses.2
The functional and psychosocial considerations of replantation versus prosthetic rehabilitation received a more direct comparison in a final clinical trial.3 In this investigation, nine patients who underwent successful replantation and 22 amputees, all of whom experienced initial traumatic amputation at the transradial level, were compared using the DASH and the Michigan Hand Questionnaire (MHQ) (See MHQ sidebar). The mean DASH scores for the replantation cohort, reported at 24.6, reasonably approximated those reported for the transplantation cohort described earlier, reported at 22.5. However, the scores for the cohorts with amputations were profoundly different, with the cohort in the present study reporting disability levels nearly four times greater than those reported by the seven subjects in the replantation study.1,3 The reasons for this disparity are unclear, though several partial explanations are plausible.
First, in the present study, prosthetics patients were "considered on an intention-to-treat basis, meaning that any patient fitted with a prosthesis was included, regardless of how much they chose to use the device." In this case, nearly one quarter of the subjects with amputations were no longer using a prosthesis, in sharp contrast to the universal, full-time use by the subjects in the transplantation trial. Additionally, while the transplantation cohort was universally managed with myoelectric prostheses, the predominant prosthesis type in the present study was body-powered, with 27 percent of the subjects only using this type of prosthesis.3 Only two subjects (9 percent) in the present study were dedicated users of a myoelectric device.3
Additional insights can be gained from the MHQ data. Here, the replantation subjects' scores were substantially higher than those of the prosthesis users in the domains of overall function (41 versus 20), activities of daily living (20 versus 6), and patient satisfaction (46 versus 24). The sole domain in which people with amputations experienced more favorable outcomes was in the domain of pain (50 versus 34, where higher scores indicated greater pain). Collectively, these findings support those associated with DASH scores, with replantation patients reporting improved function and satisfaction relative to their peers managed with amputation.
Collectively, a few principles emerge from this recent literature. When possible, particularly at the transradial level, traumatic amputation should be managed with surgical replantation. This approach appears reasonably associated with improvements in both function and patient perception. However, when replantation is not possible, decisions are less automatic. The primary advantage of hand transplantation, sensory restoration, may not adequately offset the risks associated with a lifetime of immunosuppressive medications. Also, it appears that the limitations of both transplantation and revision amputation with subsequent prosthetic management are such that roughly one-quarter of the individuals will fail to reach their optimal outcomes, either because of prosthetic abandonment by those with amputations or physiologic rejection of the transplanted extremity by surgical patients. Importantly, whether managed with revision amputation, replantation, or transplantation, all subjects experienced residual deficits in their upper-limb function. Thus, the ultimate functionality and satisfaction associated with any course of treatment can only be reasonably compared against those associated with the other management options.
Phil Stevens, MEd, CPO, FAAOP, is in clinical practice with Hanger Clinic, Salt Lake City. He can be contacted at email@example.com.
1. Salminger, S., A. Sturma, and A. D. Roche et al. 2016. Functional and psychosocial outcomes of hand transplantation compared with prosthetic fitting in below-elbow amputees: A multicenter cohort study. PLoS ONE 11(9):e0162507.
2. Otto, I. A., M. Kon, A. H. Schuurman, and L. P. van Minnen. 2015. Replantation versus prosthetic fitting in traumatic arm amputations: A systematic review. PLoS ONE 10(9):e0137729.
3. Pet, M. A., S. D. Morrison, and J. S. Mack et al. 2016. Comparison of patient-reported outcomes after traumatic upper extremity amputation: Replantation versus prosthetic rehabilitation. Injury 47:2783-8.