Buried filet of limb flaps for the reconstruction of forequarter and hindquarter amputations.

BACKGROUND AND OBJECTIVES: Forequarter and hindquarter amputations have traditionally been closed with local tissues, but the technique is plagued by a high rate of complication such as marginal necrosis, seroma, infection, and dehiscence. Filet of limb flaps have been used when local tissues are insufficient for closure, and despite their use in more extensive and complex wounds, outcomes seem to be better in these cases. Recognizing that filet of limb flaps not only serve to cover the wound, but also eliminate dead space, supplement at-risk and/or radiated tissue, pad underlying hard structures, and facilitate neuroma prevention with target muscle reinnervation, we have change our practice to utilize buried filet of limb flaps even when local tissues are technically "sufficient" to close the wound. The purpose of this article to organize and describe the ways in which buried filet-of-limb flaps can be used to achieve important and discrete surgical objectives in forequarter and hindquarter amputation, and to facilitate increased recognition of collaborative interdisciplinary opportunities for spare-part reconstruction. METHODS: Retrospective data from the medical records of seven patients, collected between 2010 to 2023 at our single tertiary referral center, were reviewed. This included all patients for whom a buried (or partially buried) filet of limb flap was attempted for forequarter or hindquarter amputation reconstruction. RESULTS: Five males and two females ranging 55 to 75 years of age, met the inclusion criteria. Three cases of forequarter amputation and four cases of hindquarter amputation were included. Six flaps were successfully transferred without major flap-related complications. The mean follow-up period was eight and a half months. CONCLUSION: Even when local tissues are technically "sufficient" to close forequarter and hindquarter amputation wounds, we have found buried filet of limb flaps to be useful in several ways. These include occupying dead space, providing double-layer coverage, padding hard structures, preventing neuromas, and reconstructing sacro- and spino-pelvic continuity. Our approach emphasizes interdisciplinary collaboration and highlights the potential advantages of buried filet of limb flaps in optimizing patient outcomes for complex limb amputations.

The Physiologic Basis of Molecular Therapeutics for Peripheral Nerve Injury: A Primer.

Peripheral nerve injuries affect a significant number of patients who experience trauma affecting the hand and upper extremity. Improving unsatisfactory outcomes from repair of these injuries remains a clinical challenge despite advancements in microsurgical repair. Imperfections of the nerve regeneration process, including imprecise reinnervation, distal axon degradation, and muscular atrophy, complicate the repair process. However, the capacity for peripheral nerves to regenerate offers an avenue for therapeutic advancement. Regeneration is a temporally and spatially dynamic process coordinated by Schwann cells and neurons among other cell types. Neurotrophic factors are a primary means of controlling cell growth and differentiation in the repair setting. Sustained axon survival and regrowth and consequently functional outcomes of nerve repair in animal models are improved by the administration of neurotrophic factors, including glial cell-derived neurotrophic factor, nerve growth factor, sterile alpha and TIR motif containing 1, and erythropoietin. Targeted and sustained delivery of neurotrophic factors through gelatin-based nerve conduits, multiluminal conduits, and hydrogels have been shown to enhance the innate roles of these factors to promote expedient and accurate peripheral nerve regeneration in animal models. These delivery methods may help address the practical limitations to clinical use of neurotrophic factors, including systemic side effects and the need for carefully timed, precisely localized release schedules. In addition, tacrolimus has also improved peripheral nerve regrowth in animal models and has recently shown promise in addressing human disease. Ultimately, this realm of adjunct pharmacotherapies provides ample promise to improve patient outcomes and advance the field of peripheral nerve repair.

A Systematic Review to Compare Electrical, Magnetic, and Optogenetic Stimulation for Peripheral Nerve Repair.

The purpose of this systematic review was to assess the currently available evidence for the use of external stimulation to modulate neural activity and promote peripheral nerve regeneration. The most common external stimulations are electrical stimulation (ES), optogenetic stimulation (OS), and magnetic stimulation (MS). Understanding the comparative effectiveness of these stimulation methods is pivotal in advancing therapeutic interventions for peripheral nerve injuries. This systematic review focused on these three external stimulation modalities as potential strategies to enhance peripheral nerve repair (PNR). We used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses framework to systematically evaluate and compare the efficiency of ES, OS, and MS in PNR. The review included studies published between 2018 and 2023 using ES, OS, or MS for PNR focused on enhancing recovery of peripheral nerve injuries in rodent models identified through PubMed and Google Scholar. The search strategies and inclusion criteria identified 19 studies (13 ES, 4 OS, and 2 MS) for detailed analysis, focusing on critical parameters such as functional recovery, histological outcomes, and electrophysiological data. Although ES demonstrated a consistent improvement in all the analyses, high-frequency repetitive MS (HFr-MS) emerged as a promising modality. HFr-MS demonstrated accelerated PNR, as histological and electrophysiological evidence indicated. In contrast, OS exhibited superior functional recovery outcomes. Notable limitations include constrained MS and OS data sets and the challenge of comparing relative improvements because of methodological diversity in evaluation techniques. Our findings underscore the potential of HFr-MS and OS in PNR while emphasizing the critical need for standardized testing protocols to facilitate meaningful cross-study comparisons. External stimulations have the potential to improve functional recovery in patients with nerve injury.

Concepts of Pain Management Following Nerve Injuries: Multidisciplinary Approach.

Purpose: A systematic review to identify treatment approaches for the management of pain following peripheral nerve injury. Methods: A published literature search was performed for the concepts of peripheral nerve injury and pain management with related synonyms. The strategies were created using a combination of controlled vocabulary terms and keywords and were executed in Embase.com, Ovid-Medline All, and Scopus from database inception. Database searches were completed on August 22, 2023. Results: The initial search resulted in a total of 1,793 citations. In total, 724 duplicates were removed, leaving 1,069 unique citations remaining for analysis. This review excluded all papers that were not specific to pain following peripheral nerve injury. Case and cohort studies (n < 5) were also excluded. Thirty-two articles on pain management strategies after peripheral nerve injury remained, with years of publication ranging from 1981 to 2023. An additional four articles were identified by manual search. Of the 36 articles reviewed, 15 articles reported on the approach to the treatment of pain after a peripheral nerve injury, and the other 22 articles consisted of cohort and case series studies. Conclusions: There is a lack of literature describing efficacy of various treatment strategies for pain following peripheral nerve injuries. Few studies provide clear, stepwise clinical guidance for practicing physicians and other health care providers on the treatment of these complicated patients.

Protocol to Develop a Core Outcomes Set for Peripheral Nerve Injury.

Background: Advances in treatment philosophies and microsurgical techniques for peripheral nerve injuries (PNI) have led to improved outcomes. However, lack of standardisation in the evaluation of clinical outcomes after PNI treatment precludes the ability to compare reconstruction methods, such as nerve transfer, nerve grafting, free functioning muscle transfers and tendon transfers. To this end, our goal is to work collaboratively to establish a core outcome set to evaluate outcomes after PNI. Methods: The protocol for this arc of work, delineated in this manuscript, consists of two phases: (1) conducting a systematic review of how outcomes are currently reported following PNI and (2) a Delphi process to gain consensus on the measures to include in the core outcome set for PNI. In the Delphi process, two online rounds will be used to gather consensus on the importance of each outcome measure. A final round will be conducted in person to discuss and resolve measures for which there is not yet consensus and to finalise the core outcomes set. Conclusions: Through this process, a common standard for reporting outcomes after PNI will be created, facilitating collaboration and future research.

Direct Economic Burden of Cubital Tunnel Surgery in the United States: Total Payments and Components of Cost.

PURPOSE: Despite its widespread prevalence, the cost of cubital tunnel syndrome (CuTS) in the United States to patients and insurers is not well understood. The purpose of this study was to quantify the direct payments associated with operative treatment of CuTS. We hypothesized that CuTS represents a substantial cost to the payer in facility fees, surgeon fees and other expenses. METHODS: Utilizing the MarketScan database of insured patients (commercial and Medicaid), we identified a cohort of 41,777 patients aged 18-64 years with surgically treated CuTS from 2006 to 2018. We estimated the median 90-day payments from encounters associated with cubital tunnel release (CuTR) and/or ulnar nerve transposition surgery by summing all payments for claims within 90 days after the index surgery. Published estimates of the annual number of cubital tunnel surgeries were used to calculate the annual expenditure. RESULTS: Of 41,777 patients, the median (interquartile range [IQR]) values of total direct payments were $5,522 [$3,426, $9,541]. With an estimated 94,645 cases/year, this leads to an annual payment of more than $522 million. Index facility payments (median[IQR] $2,555 [$1,359, $4,708] were the highest, followed by index provider payments ($1,691 [$1,328, $2,217]). The median index surgeon payment (median[IQR] $905 [$707, $1,184]) represented just over half of the provider payments. Post-operative care had a median [IQR] payment of $377 ($424, $1,987). Limitations of claims databases prevented assessment of other indirect costs associated with cubital tunnel surgery. CONCLUSIONS: Payments for the surgical treatment of CuTS from the index surgery to 90 days post-operatively have an estimated median of $5,522 per patient, totaling $52 million annually. Index facility fees are responsible for more than 46% of payments, while index payments to surgeons represent approximately 16%. Defining this data is critical to understanding one component of the economic impact of CuTS. LEVEL OF EVIDENCE: Level IV.

Effect of Screw Length in Volar Plating for Intra-articular Distal Radius Fractures: A Biomechanical Study.

PURPOSE: The purpose of this study was to compare the effect of varying screw lengths on load to failure and retention of the dorsal ulnar corner fragment after fixation of comminuted intra-articular distal radius fractures in a cadaveric model. METHODS: Twenty-four fresh frozen cadaveric forearms were subjected to a standardized distal radius osteotomy to mimic an intra-articular fracture pattern. Dual X-ray absorptiometry scans were performed to ensure minimal variability in bone density. All fractures were fixed with a volar locking plate and distal locking screws. Three different lengths of distal locking screws were used in each group of eight specimens to simulate the clinical decision of different distal screw lengths. The screw lengths tested were bicortical, 100% of the width of the bone but unicortical, and 75% of the width of the bone and unicortical. All specimens were preconditioned with cyclic axial loading and then axially loaded using matching acrylic resin molds to clinical failure and fragment displacement as detected by a motion analysis system. Retention or loss of the dorsal ulnar corner fragment during loading was recorded as a binary variable. RESULTS: Between the three groups, there were no statistically significant differences in precycling stiffness, postcycling stiffness, load at 2 mm displacement of the dorsal ulnar corner, or force at failure. The group with 75% length screws had a significantly higher loss of reduction of the dorsal ulnar corner (86%) compared with the other groups (0%). CONCLUSIONS: Varying screw lengths did not affect the stiffness or overall loads to failure of axially loaded specimens. However, the 75% length screws did not reliably secure the dorsal ulnar corner fragments. Although this did not significantly affect the overall load to failure of the construct, displacement of this fragment may have implications for rotation of the forearm through the distal radioulnar joint. CLINICAL RELEVANCE: Surgeons should consider the utilization of full-length unicortical locking screws to ensure adequate fixation of the dorsal ulnar corner. TYPE OF STUDY/LEVEL OF EVIDENCE: Biomechanical study V.

Pain Interference Prior to and 1 Year After Surgery for Adult Traumatic Brachial Plexus Injury.

PURPOSE: Pain after brachial plexus injury (BPI) can be severely debilitating and is poorly understood. We hypothesized that pain interference (PI) ("the extent to which pain hinders engagement in life") would be predicted by depression, anxiety, severity of pain symptoms, and poorer preoperative muscle function. METHODS: Among patients in a prospective multicenter BPI cohort study, 37 completed Patient-Reported Outcomes Measurement Information System (PROMIS) PI questionnaires before and 1 year after surgery. At both times, participants completed anxiety and depression questionnaires and BPI-specific measures of pain symptoms, physical limitations, and emotional recovery. Surgeon-graded muscle testing, injury severity, age at the time of injury, body mass index, and time from injury to surgery were included. We performed a bivariate analysis of predictors for preoperative and 1-year PROMIS PI followed by multivariable regression modeling using stepwise selection and Bayesian Information Criterion to select covariates. RESULTS: Before surgery, the mean PROMIS PI score was 60.8 ± 11.0, with moderate correlations between PROMIS PI and depression, as well as between PROMIS PI and functional limitations. At 1 year after surgery, the mean PROMIS PI score was 59.7 ± 9.5. There was no difference in preoperative and 1-year PROMIS PI. There were strong correlations between PROMIS PI and pain symptoms, functional limitations, and emotional aspects of recovery at the 1-year follow-up that remained significant in multivariable regression. There were no notable associations between muscle testing and PI. CONCLUSIONS: Pain interference remained substantial and elevated in BPI patients 1 year after surgery. We noted strong associations between PI and pain symptoms, functional limitations, and emotional aspects of recovery. These findings demonstrate the persistence of pain as a feature throughout life after BPI and that its treatment should be considered a priority alongside efforts to improve extremity function. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognosis IV.

Effect of Tourniquet-Related Nerve Ischemia on Response to Handheld Nerve Stimulation in Ulnar Nerve Transposition.

BACKGROUND: Tourniquet-related nerve ischemia has been well studied in several reconstructive procedures, but the time-course of impaired response to intraoperative stimulation is unclear. The present study evaluated ischemic effects on conduction during ulnar nerve transposition and examined the relationship between intra- and pre- operative diagnostics. We hypothesized that intraoperative ischemia would have minimal impact on conduction. METHODS: Thirty patients scheduled for anterior transposition were enrolled after preoperative examination, electrodiagnostic testing, and ultrasound. Demographic and symptom severity data were recorded. A handheld biphasic nerve stimulator was used intraoperatively to assess minimum amplitude and pulse duration needed for muscle response. Measurements were taken at 15-minute intervals after placement. RESULTS: Changes in threshold amplitude and pulse duration were calculated between each 15-minute interval; no significant difference was found in the change of either value (p = 0.70 and 0.178). A weak negative correlation existed between preoperative CMAP amplitudes and average intraoperative pulse duration, which increased to a moderate correlation when compared to 45-minute pulse duration (r=-0.62, p<0.01). Preoperative ulnar nerve cross-sectional area (CSA) demonstrated no significant correlation with average pulse duration but a moderate correlation with pulse duration at 45 minutes (r=0.63, p=0.01). CONCLUSIONS: Tourniquet use did not prevent effective intraoperative stimulation of the ulnar nerve for at least 45 minutes. The window for meaningful stimulation with tourniquet usage appears to be greater than previously thought. Preoperative nerve CMAP amplitude and CSA does appear to influence pulse duration required after 45 minutes of ischemia, suggesting that injured nerves are more susceptible to ischemia. LEVEL OF EVIDENCE: 1.

Biomechanical characterization of cadaveric brachial plexus regions using uniaxial tensile tests.

INTRODUCTION: The proximal regions of the brachial plexus (roots, trunks) are more susceptible to permanent damage due to stretch injuries than the distal regions (cords, terminal branches). A better description of brachial plexus mechanical behavior is necessary to better understand deformation mechanisms in stretch injury. The purpose of this study was to model the biomechanical behavior of each portion of the brachial plexus (roots, trunks, cords, peripheral nerves) in a cadaveric model and report differences in elastic modulus, maximum stress and maximum strain. METHODS: Eight cadaveric plexi, divided into 47 segments according to regions of interest, underwent cyclical uniaxial tensile tests, using a BOSE® Electroforce® 3330 and INSTRON® 5969 material testing machines, to obtain the stress and strain histories of each specimen. Maximum stress, maximum strain and elastic modulus were extracted from the load-displacement and stress-strain curves. Statistical analyses used 1-way ANOVA with post-hoc Tukey HSD (Honestly Significant Difference) and Mann-Whitney tests. RESULTS: Mean elastic modulus was 8.65 MPa for roots, 8.82 MPa for trunks, 22.44 MPa for cords, and 26.43 MPa for peripheral nerves. Differences in elastic modulus and in maximum stress were statistically significant (p < 0.001) between proximal (roots, trunks) and distal (cords, peripheral nerves) specimens. CONCLUSIONS: Proximal structures demonstrated significantly smaller elastic modulus and maximum stress than distal structures. These data confirm the greater fragility of proximal regions of the brachial plexus.

Advances in Imaging of Compressive Neuropathies.

Ultrasound and magnetic resonance neurography are useful modalities to aid in the assessment of compressive neuropathies, although they are still limited in their resolution of nerve microstructure and their capacity to monitor postoperative nerve recovery. Optical coherence tomography, a preclinical imaging modality, is promising in its ability to better identify structural and potential physiologic changes to peripheral nerves, but requires additional testing and research prior to widespread clinical implementation. Further advances in nerve imaging may elucidate the ability to visualize the zone of nerve injury intraoperatively, monitor the progression of nerve regeneration, and localize problems during nerve recovery.

Biomechanical characterization of cadaveric brachial plexus microstructure.

INTRODUCTION: Peripheral nerves consist of axons and connective tissue. The amount of connective tissue in peripheral nerves such as the brachial plexus varies proximally to distally. The proximal regions of the brachial plexus are more susceptible to stretch injuries than the distal regions. A description of the mechanical behavior of the peripheral nerve components is necessary to better understand the deformation mechanisms during stretch injuries. The purpose of this study was to model the biomechanical behavior of each component of the peripheral nerves (fascicles, connective tissue) in a cadaveric model and report differences in elastic modulus, maximum stress and maximum strain. METHODS: Forty-six specimens of fascicles and epi-perineurium were subjected to cyclical uniaxial tensile tests to obtain the stress and strain histories of each specimen, using a BOSE® Electroforce® 3330 and INSTRON® 5969 materials testing machines. Maximum stress, maximum strain and elastic modulus were extracted from the load-displacement and stress-strain curves, and analyzed using Mann-Whitney tests. RESULTS: Mean elastic modulus was 6.34 MPa for fascicles, and 32.1 MPa for connective tissue. The differences in elastic modulus and maximum stress between fascicles and connective tissue were statistically significant (p < 0.001). CONCLUSIONS: Peripheral nerve connective tissue showed significantly higher elastic modulus and maximum stress than fascicles. These data confirm the greater fragility of axons compared to connective tissue, suggesting that the greater susceptibility to stretch injury in proximal regions of the brachial plexus might be related to the smaller amount of connective tissue.

A Prospective Randomized Pilot Study: One-Year Outcomes of Ligament Reconstruction Tendon Interposition Versus Suture Tape Suspensionplasty for Thumb Carpometacarpal Joint Arthritis.

PURPOSE: We performed a randomized controlled trial assessing patient-reported outcome measures following trapeziectomy with ligament reconstruction and tendon interposition (LRTI) or suture tape suspensionplasty (STS) for treatment of thumb carpometacarpal joint osteoarthritis. METHODS: Patients undergoing surgery for thumb carpometacarpal joint osteoarthritis were prospectively randomized to LRTI or STS. Outcome measures were collected at 2 weeks, 4 weeks, 3 months, and 1 year and included visual analog scale pain, Patient-Reported Outcomes Measurement Information System (PROMIS) Upper Extremity, return to work/activity, range of motion, grip/pinch strength, and complications. RESULTS: Thirty-one patients (32 thumbs) were randomized from 51 patients offered participation over two years. One-year follow-up was 97%. Both groups had a decrease in visual analog scale pain scores at all postoperative time points. The trajectory of postoperative Patient-Reported Outcomes Measurement Information System Upper Extremity scores was similar, and both groups achieved the meaningful clinically important difference for improvement in PROMIS Upper Extremity by three months. Grip strength was substantially increased in both groups at one year. Return to work/activity and surgical complications favored the LRTI group. CONCLUSIONS: Our study did not suggest any clinically relevant differences in the postoperative patient-reported outcome measures or objective clinical measurements between LRTI and STS, although LRTI patients had a faster return to work/activity and lower complication rates. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IIB.

Development and Assessment of a Patient "Journey Guide" for Adult Traumatic Brachial Plexus Injury.

BACKGROUND: Patients with a traumatic brachial plexus injury (BPI) have previously identified the need for improved patient education tools, emphasizing the importance of communicating outcome expectations, providing attention to the emotional aspects of the injury and the treatment of pain, and acknowledging the needs of caregivers. We created a journey guide, a BPI-specific educational tool, to address these deficiencies. In this study, we determined the acceptability of the journey guide through surveys of and semistructured interviews with patients with a BPI. METHODS: The journey guide was created by a multidisciplinary team focusing on previously defined areas for the improvement of patient education and care delivery related to BPI. To assess the acceptability of the journey guide, we recruited 19 participants from the brachial plexus clinic of our institution and the United Brachial Plexus Network to complete a series of surveys and semistructured interviews. Participants completed surveys regarding their satisfaction with the journey guide, and we conducted semistructured interviews to assess patient BPI experiences and impressions of the journey guide and to seek feedback. Interview transcripts were qualitatively analyzed to determine common themes for improvement. RESULTS: A total of 19 participants with a mean age of 44.7 years were included. The cohort was predominantly male (13 participants) and White (16 participants). The mean time since BPI was 12.9 years, ranging from 2.0 to 39.7 years. On a visual analog scale, satisfaction with the journey guide was given a mean score of 8.4; expected usefulness when a patient is first injured, 8.7; potential for continued use, 7.3; and the fit for the BPI community, 8.8. Qualitative analysis demonstrated a primarily positive view of the guide and identified 4 major themes: (1) visuals and quotes improve clarity and engagement, (2) the journey guide would be most useful immediately following an injury, (3) the journey guide is an effective organizational tool, and (4) it is difficult to orient patients toward future hardships. CONCLUSIONS: The journey guide successfully filled a gap in the current care for BPI and was largely deemed acceptable by patients with a BPI. Specifically, participants found the journey guide to be a concise educational resource and an effective organizational tool. Participants also indicated that areas for improvement include the increased use of graphics and images and recognition of the greater BPI community with which patients can engage.

Trapeziectomy with Ligament Reconstruction/ Suspensionplasty Compared to Suture Tape Suspensionplasty for the Surgical Treatment of Advanced Thumb Carpometacarpal Osteoarthritis.

Purpose: Trapeziectomy with tendon reconstruction/suspensionplasty (TRS) is the most commonly performed surgical procedure in the United States for treatment of thumb carpometacarpal (CMC) osteoarthritis (OA). Trapeziectomy with suture tape suspensionplasty (STS) has been used recently at the study institution as an alternative surgical treatment option with perceived benefits of earlier return to function and reduced operative time. The purpose of this study was to compare patient outcomes following TRS versus STS for treatment of thumb CMC OA. Methods: All patients who underwent primary, isolated TRS or STS for treatment of thumb CMC OA between 1/1/2014 and 9/1/2020 were analyzed. We assessed demographics and preoperative and postoperative patient-rated outcome scores including Patient-reported outcomes measurement information system scores as well as pain outcomes, satisfaction, and appearance at a mean of 2.6 years after surgery (minimum 6 months). Time to return to work and activities was compared between groups. Bivariate statistics compared outcomes between groups. Results: Ninety-four patients were included in the final study cohort, of which 53 underwent TRS and 41 underwent STS. There were no differences in preoperative, postoperative, or final patient-rated outcome scores between groups. Patients reported high global and appearance satisfaction scores at final follow-up in both groups. Mean tourniquet time was 15 minutes (26%) shorter and return to work was on average 3 weeks faster for the STS group. Conclusions: There were no differences in postoperative patient-rated outcome scores between the STS and TRS groups. The STS group had a shorter surgical time and faster return-to-work after surgery. Type of study/level of evidence: Therapeutic III.

Toward peripheral nerve mechanical characterization using Brillouin imaging spectroscopy.

Significance: Peripheral nerves are viscoelastic tissues with unique elastic characteristics. Imaging of peripheral nerve elasticity is important in medicine, particularly in the context of nerve injury and repair. Elasticity imaging techniques provide information about the mechanical properties of peripheral nerves, which can be useful in identifying areas of nerve damage or compression, as well as assessing the success of nerve repair procedures. Aim: We aim to assess the feasibility of Brillouin microspectroscopy for peripheral nerve imaging of elasticity, with the ultimate goal of developing a new diagnostic tool for peripheral nerve injury in vivo. Approach: Viscoelastic properties of the peripheral nerve were evaluated with Brillouin imaging spectroscopy. Results: An external stress exerted on the fixed nerve resulted in a Brillouin shift. Quantification of the shift enabled correlation of the Brillouin parameters with nerve elastic properties. Conclusions: Brillouin microscopy provides sufficient sensitivity to assess viscoelastic properties of peripheral nerves.

Mechanomyography as a Surgical Adjunct for Treatment of Chronic Entrapment Neuropathy: A Case Series.

BACKGROUND: Chronic entrapment neuropathy results in a clinical syndrome ranging from mild pain to debilitating atrophy. There remains a lack of objective metrics that quantify nerve dysfunction and guide surgical decision-making. Mechanomyography (MMG) reflects mechanical motor activity after stimulation of neuromuscular tissue and may indicate underlying nerve dysfunction. OBJECTIVE: To evaluate the role of MMG as a surgical adjunct in treating chronic entrapment neuropathies. METHODS: Patients 18 years or older with cubital tunnel syndrome (n = 8) and common peroneal neuropathy (n = 15) were enrolled. Surgical decompression of entrapped nerves was performed with intraoperative MMG of the hypothenar and tibialis anterior muscles. MMG stimulus thresholds (MMG-st) were correlated with compound muscle action potential (CMAP), motor nerve conduction velocity, baseline functional status, and clinical outcomes. RESULTS: After nerve decompression, MMG-st significantly reduced, the mean reduction of 0.5 mA (95% CI: 0.3-0.7, P < .001). On bivariate analysis, MMG-st exhibited significant negative correlation with common peroneal nerve CMAP ( P < .05), but no association with ulnar nerve CMAP and motor nerve conduction velocity. On preoperative electrodiagnosis, 60% of nerves had axonal loss and 40% had conduction block. The MMG-st was higher in the nerves with axonal loss as compared with the nerves with conduction block. MMG-st was negatively correlated with preoperative hand strength (grip/pinch) and foot-dorsiflexion/toe-extension strength ( P < .05). At the final visit, MMG-st significantly correlated with pain, PROMIS-10 physical function, and Oswestry Disability Index ( P < .05). CONCLUSION: MMG-st may serve as a surgical adjunct indicating axonal integrity in chronic entrapment neuropathies which may aid in clinical decision-making and prognostication of functional outcomes.

Future Considerations in the Diagnosis and Treatment of Compressive Neuropathies of the Upper Extremity.

Compressive neuropathies of the upper extremity are among the most common conditions seen by hand surgeons. The diagnoses of carpal tunnel syndrome and cubital tunnel syndrome have traditionally been made by a combination of history, physical examination, and electrodiagnostic testing. However, findings can be nonspecific and electrodiagnostic testing is invasive for the patient. The diagnosis of compressive neuropathies continues to evolve as technology advances, and newer diagnostic modalities predominantly focus on preoperative diagnostic imaging with ultrasound and magnetic resonance imaging/neurography. With the advent of cheaper, faster, and less invasive imaging, the future may bring a paradigm shift away from electrophysiology as the gold standard for the preoperative diagnosis of compressive neuropathies. Intraoperative imaging of nerve health is an emerging concept that warrants further investigation, whereas postoperative imaging of nerve recovery with ultrasound and magnetic resonance imaging currently has a limited role because of nonspecific findings and potential for misinterpretation. Advances in surgical treatment of compressive neuropathies appear to center around the use of imaging for less invasive neurolysis techniques and other adjunctive treatments with nerve decompression. The management of failed peripheral nerve decompressions and recurrent compressive neuropathies remains challenging.

The Influence of Psychosocial Factors on Disability and Expected Improvement Before Surgery for Adult Traumatic Brachial Plexus Injury.

PURPOSE: Psychosocial factors influence pain and recovery after extremity trauma and may be targets for early intervention. This may be of particular interest for patients with adult traumatic brachial plexus injury (BPI), given the broad and devastating impact of the injury. We hypothesized that there would be an association between depressive symptoms, anxiety, and pain interference with preoperative disability and expectations for improvement after BPI surgery. METHODS: We enrolled 34 patients into a prospective multicenter cohort study for those undergoing surgery for adult traumatic BPI. Before surgery, participants completed Patient-Reported Outcome Measurement Information System scales for pain interference, anxiety, and depressive symptoms, and a validated BPI-specific measure of disability and expected improvement. We performed Pearson correlation analysis between pain interference, anxiety symptoms, and depressive symptoms with (A) disability and (B) expected improvement. We created separate linear regression models for (A) disability and (B) expected improvement including adjustment for severity of plexus injury, age, sex, and race. RESULTS: Among 34 patients, there was a moderate, statistically significant, correlation between preoperative depressive symptoms and higher disability. This remained significant in a linear regression model adjusted for severity of plexus injury, age, sex, and race. There was no association between severity of plexus injury and disability. Depressive symptoms also were moderately, but significantly, correlated with higher expected improvement. This remained significant in a linear regression model adjusted for severity of plexus injury, age, sex, and race. CONCLUSIONS: Depressive symptoms are associated with greater disability and higher expected improvement before BPI surgery. Screening for depressive symptoms can help BPI teams identify patients who would benefit from early referral to mental health specialists and tailor appropriate expectations counseling for functional recovery. We did not find an association between severity of BPI and patient-reported disability, suggesting either that the scale may lack validity or that the sample is biased. LEVEL OF EVIDENCE: Prognostic II.

Factors Influencing Patient Experience After Cubital Tunnel Syndrome Surgery.

PURPOSE: The purpose of this study was to use qualitative methodology to better understand patient experiences after cubital tunnel surgery, with the goal of identifying areas of improvement in delivery of care. METHODS: Patients who underwent surgery (in situ decompression or anterior transposition) for cubital tunnel syndrome within the last 12 months, which was performed by one of three fellowship-trained hand surgeons, were identified. Participants were invited to an interview regarding "their experiences with ulnar nerve surgery." An interview guide with semistructured, open-ended questions regarding the decision for surgery, treatment goals, and the recovery process was used. Interim data analyses were conducted to assess emerging themes, and interviews were continued until thematic saturation was achieved. RESULTS: Seventeen participants completed interviews; the mean age of study participants was 57 years, and 71% were women. The mean time between surgery and the interview was 6 months. Participants identified the following two key areas that could improve their surgical experience: (1) the need for detailed preoperative education about the surgery and recovery process, (2) and the importance of discussing treatment goals and expectations. Participants suggested providing both written and online resources to patients, including specific details about incision size and recovery process in education materials, and setting expectations for symptom resolution. CONCLUSIONS: Although the overall patient experience after cubital tunnel surgery was positive, participants noted that there is a need for providing improved educational resources and counseling before surgery. CLINICAL RELEVANCE: Addressing education and counseling needs before cubital tunnel surgery will help surgeons to improve delivery of care.