“Assessment of Tree-Based Statistical Learning to Estimate Optimal Personalized Treatment Decision Rules for Traumatic Finger Amputations” by Speth et al1 is a retrospective, multicenter cohort study using innovative statistical methods to create a clinical algorithm for finger amputations based on specific functional outcomes. In the article, the authors have endeavored to provide an objective, methodical approach to the decision about replantation, which would be immensely valuable for hand surgeons.
Given concerns about the efficacy and functional outcomes following replantation, the overall trend for replantation in the United States has declined since the early 2000s.2 Recently, there has been a resurgence of interest in replantation surgery, particularly in Asian countries, owing to technological advances and increasing efficiency with replantation surgery.3 Although contemporary indications for replantation have recently been described,4 the decision for patients with finger amputations is not a one-size-fits-all approach; each patient is inherently different and requires a personalized approach to care. Speth et al1 aimed to create a treatment algorithm, which is challenging given the emergent nature of these problems and the innate heterogeneity in this patient population.
As with any retrospective study, one considerable limitation of the article is selection bias; the decision about replantation vs revision amputation was made by the treating surgeon, and myriad factors were therefore taken into consideration (in addition to the factors described in the article). For finger amputations, the presence of an avulsion mechanism and the extent of soft tissue and bony injuries are critically important and difficult to quantify in a retrospective study, but they likely played a substantial role in clinical decision making.
One striking recommendation of the study, that patients with isolated thumb amputations should undergo revision amputation, is antithetical to traditional teaching and therefore should be further studied before it is accepted as a primary treatment strategy.5 The thumb constitutes approximately 40% of hand function, and thumb amputations have generally been considered an incontrovertible indication for replantation. Despite the authors’ recommendations, I suspect that most surgeons involved in this study would desire replantation for their own (or a family member’s) amputated thumb. Another interesting finding in this study is the recommendation for revision amputation following finger amputation in the dominant hand; this is also contrary to conventional teaching and would benefit from further confirmatory study.
Pain is an important outcome metric for extremity injuries, particularly amputations, and has a significant influence on ultimate hand function. Speth et al1 found that replantation (ie, nerve repair or nerve reconstruction) was preferable to revision amputation with regard to pain, and this finding is commensurate with existing and emerging data. A previous study from our group queried more than 1000 patients who underwent completion amputation for finger amputation and found that the rate of symptomatic neuroma for which surgery was performed was 6.6%, indicating that many patients will undergo additional surgery because of persistent pain following revision amputation.6 Replantation appears to be superior to revision amputation from a neuropathic pain standpoint, as it confers a functional destination to the nerve endings (instead of becoming an inevitable terminal neuroma) and provides a pathway for nerve regeneration toward the terminal aspect of the finger.
Another important factor in the decision for replantation that was not thoroughly described in the article is surgeons’ expertise and experience and their technical ability to restore function to amputated fingers. It is unquestionably true that the surgeons included in the study are world experts and leaders in microvascular hand surgery, but it is also important to note that optimal outcomes following replantation occur most commonly with experienced surgeons and at centers of excellence.7 With the developing regionalization of microvascular hand trauma centers in the United States through the American Society for Surgery of the Hand, the provision of care for finger amputations should be provided by centers with demonstrable expertise.8
How hand surgeons should use the data and recommendations of this study is not perfectly clear. The authors cogently describe 4 variables important to patients, including hand strength, pain, dexterity, and hand-related quality of life, but these can be difficult to ascertain and rank in order of importance in the acute traumatic setting when there is limited time to glean personal but critical patient information. In my experience, most patients desire replantation if this is presented as an option and have difficulty understanding the recommendation for revision amputation, even if data are provided and particularly if replantation appears to be technically feasible. The methods and tree-based statistical learning in this study can only accommodate 1 variable at a time and cannot take into account all 4 variables simultaneously. This method of analysis would have a much greater effect if the decision rules could incorporate more than 1 treatment goal and therefore recommend a single composite treatment based on all variables concurrently.
Overall, this study by Speth et al1 uses a novel tree-based learning model to provide treatment recommendations for patients with finger amputations. Surgeons should use all available patient and injury information as well as clinical experience to make the optimal decision for patients presenting with finger amputations. The authors, along with all surgeons in the FRANCHISE (Finger Replantation and Amputation Challenges in Assessing Impairment, Satisfaction, and Effectiveness) group, have contributed to our fundamental understanding of the management of finger amputations and are to be congratulated for their work.
Published: February 21, 2020. doi:10.1001/jamanetworkopen.2019.21689
Open Access: This is an open access article distributed under the terms of the CC-BY License. © 2020 Eberlin KR. JAMA Network Open.
Corresponding Author: Kyle R. Eberlin, MD, Division of Plastic and Reconstructive Surgery, Massachusetts General Hospital, Harvard Medical School, Wang Ambulatory Care Center, Suite 435, 15 Parkman St, Boston, MA 02114 (firstname.lastname@example.org).
Conflict of Interest Disclosures: Dr Eberlin reported receiving personal fees for consulting from AxoGen, Integra, and Checkpoint outside the submitted work and does not have a financial interest in any of the products, devices, or drugs mentioned in this manuscript.
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Eberlin KR. Personalized Treatment for Finger Amputations—What Should We Do With the Thumb? JAMA Netw Open. 2020;3(2):e1921689. doi:10.1001/jamanetworkopen.2019.21689
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