Long-term clinical outcome after epineural coaptation of digital nerves

Revealing digital nerve lesions-A comprehensive analysis of 2084 cases of a specialized center

BACKGROUND

Finger nerve injuries have a significant impact on hand function and can result in reduced sensation, pain and impaired coordination. The socioeconomic implications of these injuries include decreased workplace productivity, reduced earning potential, and financial burdens associated with long-term medical treatment and rehabilitation. However, there is a lack of comprehensive literature regarding the incidence, mechanisms, and associated injuries of finger nerve lesions.

METHODS

A retrospective analysis was conducted on patients treated at our institution from January 2012 to July 2020. Cases of peripheral finger nerve lesions were identified using the digital hospital information system and ICD-10 Classification. Exclusion criteria included injuries to the median nerve at the carpal tunnel level or superficial branch of the radial nerve. Data were collected using a pseudonymized approach, and statistical analyses were performed using SPSS Statistics (Version 27).

RESULTS

A total of 2089 finger nerve lesions were analyzed, with a majority of cases occurring in men. Most injuries97.4 % were caused by trauma, predominantly cut/tear injuries. Isolated finger nerve injuries were more common than multiple nerve injuries, with the index finger being the most frequently affected. Concomitant tendon and vascular injuries were observed in a significant proportion51.7 % of cases. Surgical management included direct nerve coaptation, interposition grafting and neurolysis.

DISCUSSION

Finger nerve injuries are the most prevalent type of nerve injury, often resulting from small lacerations. These injuries have substantial societal costs and can lead to prolonged sick leave. Understanding the epidemiology and etiology of finger nerve injuries is crucial for implementing effective preventive measures. Accompanying tendon injuries and the anatomical location of the nerve lesions can impact sensory recovery and treatment outcomes. Proper management of peripheral finger nerve lesions is essential for optimizing functional outcomes and minimizing the impact on daily activities. Treatment options should be tailored to the severity and underlying cause of the nerve injury.

Impact of Comorbidities on Sensory Return After Breast Reconstruction

PURPOSE

Breast anesthesia after mastectomy and reconstruction has been an ongoing concern with few improvements made in recent years. At present, there is a lack of studies evaluating the impact of comorbidities on sensation restoration. Identifying risk factors (RF) will be helpful with preoperative counseling.

METHODS

This was a prospective study on patients who underwent mastectomy and immediate implant-based or neurotized deep inferior epigastric perforator (DIEP) flap-based reconstruction. Neurosensory testing was performed at predefined time points using a pressure specified device. Patients were stratified based on reconstruction type and comorbidities, including obesity (≥30 kg/m2), age (>55 years), hypertension, alcohol use, and smoking status. Sensory comparisons among the comorbidity groups were conducted using unpaired 2-sample t tests.

RESULTS

A total of 239 patients were included in this study with 109 patients in the implant cohort and 131 patients in the DIEP cohort. One patient underwent bilateral reconstruction using both reconstructive modalities. Preoperatively, age older than 55 years was identified as an RF for reduced breast sensation in the implant cohort (difference in threshold, 10.7 g/mm2), whereas obesity was identified as an RF in the DIEP cohort (difference in threshold, 8 g/mm2). During the first 2 years postreconstruction, age older than 55 years and tobacco use history were found to be negatively correlated with breast sensation for both cohorts. With DIEP reconstruction specifically, obesity was identified as an additional RF during the early postoperative period. Of note, none of the comorbidities were found to be long-term RFs for reduced breast sensitivity. All breast sensation levels returned to comparable levels across all comorbidities by 4 years postreconstruction.

CONCLUSIONS

Currently, various comorbidities have been recognized as RFs for several postoperative complications including extended postoperative stay, necrosis, infection, and reoperation. However, our findings suggest that, although age, smoking history, and obesity showed transient associations with reduced breast sensation during the initial years postreconstruction, they play no role in the long-term potential of sensory nerve regeneration.

Conduit/Wrap Repairs to Digital Nerves Provide Residual Strength After Peak Loading

BACKGROUND

Many techniques are used for digital nerve repair, most commonly coaptation by sutures. Nerve repairs must be strong while offering an environment for nerve regeneration. Sutures can damage the nerve and thereby limit growth and regeneration. Sutures can rip and cause sudden catastrophic failure. Fibrin glue and conduit-wraps allow a good environment for growth, but neither provides much strength. A benefit to conduit repair would arise if the repair maintained integrity after the peak load so that the path for regrowth stayed in place. The goal for this study was to determine whether conduit with glue provides continued strength after a maximum load is reached.

METHODS

Digital cadaveric nerves were harvested and repaired with 2 epineurial sutures, conduit, and fibrin glue in all combinations. Tests to failure were performed, gap displacement between nerve ends recorded, and the postpeak load energy to dissociation of the nerve and conduit was calculated.

RESULTS

Conduit with glue and 2 sutures at the end had the greatest energy and displacement after the peak load but was not significantly different than conduit with glue and 1 suture. Conduit with glue alone obtained statistically the same displacement as conduit with glue and 2 sutures. Conduit, with or without glue, and 2 sutures was statistically the same as suture only repair for peak load.

CONCLUSION

Conduit/wrap maintains a load capacity and a path for nerve regeneration after the peak. Suture at the ends of conduit, not at the coaptation site, reduces damage at the point of injury.

Treatment options for digital nerve injury: a systematic review and meta-analysis

BACKGROUND

Surgical treatment of finger nerve injury is common for hand trauma. However, there are various surgical options with different functional outcomes. The aims of this study are to compare the outcomes of various finger nerve surgeries and to identify factors associated with the postsurgical outcomes via a systematic review and meta-analysis.

METHODS

The literature related to digital nerve repairs were retrieved comprehensively by searching the online databases of PubMed from January 1, 1965, to August 31, 2021. Data extraction, assessment of bias risk and the quality evaluation were then performed. Meta-analysis was performed using the postoperative static 2-point discrimination (S2PD) value, moving 2-point discrimination (M2PD) value, and Semmes-Weinstein monofilament testing (SWMF) good rate, modified Highet classification of nerve recovery good rate. Statistical analysis was performed using the R (V.3.6.3) software. The random effects model was used for the analysis. A systematic review was also performed on the other influencing factors especially the type of injury and postoperative complications of digital nerve repair.

RESULTS

Sixty-six studies with 2446 cases were included in this study. The polyglycolic acid conduit group has the best S2PD value (6.71 mm), while the neurorrhaphy group has the best M2PD value (4.91 mm). End-to-side coaptation has the highest modified Highet's scoring (98%), and autologous nerve graft has the highest SWMF (91%). Age, the size of the gap, and the type of injury were factors that may affect recovery. The type of injury has an impact on the postoperative outcome of neurorrhaphy. Complications reported in the studies were mainly neuroma, cold sensitivity, paresthesia, postoperative infection, and pain.

CONCLUSION

Our study demonstrated that the results of surgical treatment of digital nerve injury are generally satisfactory; however, no nerve repair method has absolute advantages. When choosing a surgical approach to repair finger nerve injury, we must comprehensively consider various factors, especially the gap size of the nerve defect, and postoperative complications. Type of study/level of evidence Therapeutic IV.

Digital Nerve Injury: Assessment and Treatment

Undertreated digital nerve injuries may result in sensory deficits and pain. Early recognition and treatment will optimize outcomes, and providers should maintain a high index of suspicion when assessing patients with open wounds. Acute, sharp lacerations may be amenable to direct repair while avulsion injuries or delayed repairs require adequate resection and bridging with nerve autograft, processed nerve allograft, or conduits. Conduits are most appropriate for gaps less than 15 mm, and processed nerve allografts have demonstrated reliable outcomes across longer gaps.

Cold sensitivity, functional disability and predicting factors after a repaired digital nerve injury

To investigate self-reported cold sensitivity and functional disability after a repaired digital nerve injury. We identified 3204 individuals operated with digital nerve repair in the Swedish national quality registry for hand surgery (HAKIR). Patient-reported symptoms, including cold sensitivity and perceived disability, were examined using two questionnaires (HQ-8 and QuickDASH), three and 12 months postoperatively. Patients with diabetes (n = 48; 3%) were identified in the Swedish National Diabetes Register (NDR). Cold sensitivity (scored 0–100) was the most prominent symptom among 1553 included individuals (998 men, 555 women; median age 41 [IQR 27–54] years). In the regression analysis, flexor tendon injury, hand fracture and injury to multiple structures predicted worsened cold sensitivity (6.9, 15.5 and 25.0 points; p = 0.005, 0.046 and < 0.001) at 12 months. Individuals with moderate (30–70) and severe (> 70) cold sensitivity had higher QuickDASH scores at three and 12 months postoperatively than individuals with mild cold sensitivity (6.0 and 5.5; 19.8 and 21.0 points; p = 0.001). Flexor tendon injury, injuries to multiple structures and diabetes had significant effect on QuickDASH scores at three, but not at 12, months postoperatively. Cold sensitivity is common after a digital nerve repair and impacts self-reported disability. A concomitant injury, particularly multiple injuries, predicts postoperative cold sensitivity.

Evidence-Based Approach to Timing of Nerve Surgery: A Review

ABSTRACT

Events causing acute stress to the health care system, such as the COVID-19 pandemic, place clinical decisions under increased scrutiny. The priority and timing of surgical procedures are critically evaluated under these conditions, yet the optimal timing of procedures is a key consideration in any clinical setting. There is currently no single article consolidating a large body of current evidence on timing of nerve surgery. MEDLINE and EMBASE databases were systematically reviewed for clinical data on nerve repair and reconstruction to define the current understanding of timing and other factors affecting outcomes. Special attention was given to sensory, mixed/motor, nerve compression syndromes, and nerve pain. The data presented in this review may assist surgeons in making sound, evidence-based clinical decisions regarding timing of nerve surgery.

Fibrin Glue and Conduit Form a Composite Structure in Digital Nerve Repair

Repair of severed nerves without auto- or allograft has included suture, suture with glue alone, suture with conduit and suture with glue augmentation to conduit, where use of conduit is considered for separation of the nerve ends from 5mm to 3cm. Repairs must not only serve acutely to provide apposition of nerve ends but must enable the healing of the nerve. Using biological conduit can place suture at the ends of the conduit while fibrin glue alone eliminates suture but with limited strength. The combination of conduit and glue offers the growth guidance of conduit with sufficient strength from the glue to maintain the nerve within the conduit. The role of glue in the repair integrity remains an open question, however. We sought to determine the factors in the strength of a glue-conduit-nerve construct and include consideration of standard suture repair. Fresh-frozen cadaveric digital nerves were repaired with suture alone, with glue alone or with suture and glue together and loaded to failure. Previously tested specimens with conduit, suture and glue were considered for comparison. The suture alone (2.02N) and suture with glue (2.24N) were not statistically different from each other but were statistically stronger than glue alone (0.15N). Compared to the earlier results of the strength of conduit with glue (0.65N), these results show that the glue and conduit act together. The increased area over which the glue adheres to the nerve and conduit creates a composite structure stronger than either alone.

Long-term sensibility outcomes of secondary digital nerve reconstruction with sural nerve autografts: a retrospective study

Background

Recovery of sensibility after digital nerve injury is crucial for restoring normal hand function. We evaluated long-term outcomes of digital nerve reconstruction with autografts.

Methods

This retrospective study included patients who underwent secondary reconstruction of digital nerves with nerve autografting. Recovery of sensibility was evaluated based on the following: patient self-assessment, two-point discrimination (2PD), and a total sensation score (sum of proprioception, temperature sensation, and sharp/dull discrimination). Mixed models regression was used to study predictors of sensibility outcomes. The predictors analyzed were age, sex, smoking status, number of fingers involved in a patient (as a measure of injury severity), time to reconstruction, and time to follow-up.

Results

In 61 patients, 174 digital nerves in 126 fingers were reconstructed after an average of 33.1 weeks from injury. The mean follow-up was 6.4 years from reconstruction. The mean graft length was 3.6 cm. Self-rated sensibility in the affected area was very good in 13% of patients, good in 33%, satisfactory in 40%, and poor in 24%. 2PD at 6 mm was present in 17% of patients, at 10 mm in 12%, and at 15 mm in 18% (mean 2PD was 10.8). Proprioception was preserved in 107 (85%) fingers, sensation of temperature was preserved in 99 (75%) of fingers, and sharp/dull discrimination in 88 (70%) fingers. Time from injury to reconstruction was the only significant predictor of the total sensation score.

Conclusion

Our data indicate that earlier reconstruction is associated with a favorable outcome.

Safety and efficacy of a nerve matrix membrane as a collagen nerve wrapping: a randomized, single-blind, multicenter clinical trial

A new nerve matrix membrane derived from decellularized porcine nerves has been shown to retain the major extracellular matrix components, and to be effective in preventing adhesion between the nerve anastomosis sites and the surrounding tissues in a rat sciatic nerve transection model, thereby enhancing regeneration of the nerve. The effectiveness of the membrane may be attributed to its various bioactive components. In this prospective, randomized, single-blind, parallel-controlled multicenter clinical trial, we compared the safety and efficacy of the new nerve matrix membrane with a previously approved bovine tendon-derived type I collagen nerve wrapping. A total of 120 patients with peripheral nerve injury were recruited from Beijing Jishuitan Hospital, The First Bethune Hospital of Jilin University, and Yantai Yuhuangding Hospital, China. The patients were randomly assigned to undergo end-to-end and tension-free neurorrhaphy with nerve matrix membrane (n = 60, 52 male, 8 female, mean age 41.34 years, experimental group) or tendon-derived collagen nerve wrapping (n = 60, 42 male, 18 female, mean age 40.17 years, control group). Patients were followed-up at 14 ± 5, 30 ± 7, 90 ± 10 and 180 ± 20 days after the operation. Safety evaluation included analyses of local and systemic reactions, related laboratory tests, and adverse reactions. Efficacy evaluation included a static 2-point discrimination test, a moving 2-point discrimination test, and a Semmes–Weinstein monofilament examination. Sensory nerve function was evaluated with the British Medical Research Council Scale and Semmes–Weinstein monofilament examination. The ratio (percentage) of patients with excellent to good results in sensory nerve recovery 180 ± 20 days after the treatment was used as the primary effectiveness index. The percentages of patients with excellent to good results in the experimental and control groups were 98.00% and 94.44%, respectively, with no significant difference between the two groups. There were no significant differences in the results of routine blood tests, liver and renal function tests, coagulation function tests, or immunoglobulin tests at 14 and 180 days postoperatively between the two groups. These findings suggest that the novel nerve matrix membrane is similar in efficacy to the commercially-available bovine-derived collagen membrane in the repair of peripheral nerve injury, and it may therefore serve as an alternative in the clinical setting. The clinical trial was approved by the Institutional Ethics Committee of Beijing Jishuitan Hospital, China (approval No. 20160902) on October 8, 2016, the Institutional Ethics Committee of the First Bethune Hospital of Jilin University, China (approval No. 160518-088) on December 14, 2016, and the Institutional Ethics Committee of Yantai Yuhuangding Hospital, China (approval No. 2016-10-01) on December 9, 2016. The clinical trial was registered with the Chinese Clinical Trial Registry (registration number: ChiCTR2000033324) on May 28, 2020.

Scalpel edge roughness affects post-transection peripheral nerve regeneration

Background

Gentle and precise tissue dissection reduces collateral tissue damage and preserves its structural quality for optimizing healing. This is particularly true for peripheral nerve neurorrhaphy. Axon regeneration kinetics across the repair is dependent on the amount of intraneural fibrosis. The purpose of this study was to determine whether scalpel blade smoothness was a deterministic factor in the kinetics of postneurorrhaphy peripheral axon regeneration.

Methods

Scalpel transection of the saphenous nerve was performed in 18 female Hartley guinea pigs either by a standard #15 stainless steel scalpel blade or a highly polished version of the same blade. Compound nerve action potential recordings and histochemical assay of neurofilament density proximal and 1 cm distal to the site of nerve transection were quantified postneurorrhaphy at postoperative weeks 5, 9, and 12.

Results

There was no action potential transmission observed in the distal axons immediately after neurorrhaphy. A substantial acceleration of axonal conduction recovery was observed in nerves transected with polished scalpel blades observed by high compound nerve action potential amplitudes at postneurorrhaphy weeks 5 and 9 (P < .05). In addition, an increased recovery of intra-axonal neurofilament density in nerves transected with polished scalpel blades was observed by postoperative week 5 (P < .05).

Conclusion

The quality of the scalpel blade is an important determinate of postsurgical healing. Gentle handling of tissue matters.

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Precise nerve resection reduces lateral axonal injury.

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Collateral nerve damage increases interneural fibrosis that slows regeneration.

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Smoother scalpel blades result in faster structural and functional nerve recovery.

Retrograde versus anterograde palm venous anastomosis in avulsion distal fingertip trauma: Functional and therapeutic outcomes (FTO) analysis

BACKGROUND/OBJECTIVES

The advance in the microvascular surgeries has made successful replantation of amputee fingertip or toe. Anterograde palm venous anastomosis is generally preferred in avulsion distal fingertip trauma surgeries but is technically challenging. The retrograde venous anastomosis is proved to be easy and effective in larger defects hand reconstruction surgeries. The purposes of the analysis were to compare functional and therapeutic outcomes of retrograde palm venous anastomosis against anterograde palm venous anastomosis in the avulsion distal fingertip and thumb microvascular surgery.

METHODS

Digits were replanted by retrograde palm venous anastomosis (n = 130, RPVA cohort) or anterograde palm venous anastomosis (n = 220, APVA cohort). The data regarding the survival of transplanted tissues, analgesia, 2-points discrimination, and total active movement after 2-years of surgeries were collected and analyzed.

RESULTS

A higher percentage of digits with survived transplanted tissues found in the RPVA cohort than the APVA cohort (p = 0.004). 2-points discrimination found higher in the APVA cohort than the RPVA cohort (5.22 ± 1.56 mm vs. 4.81 ± 1.39 mm, p = 0.014). The pain was fewer in the RPVA cohort than the APVA cohort (p = 0.041). A total active motion was higher in the RPVA cohort than the APVA cohort (p = 0.025). Anterograde palm venous anastomosis (p = 0.021) were associated with the failure of transplanted digits tissues.

CONCLUSIONS

Retrograde palm venous anastomosis had better functional and therapeutic outcomes than anterograde palm venous anastomosis in avulsion distal fingertip trauma.

LEVEL OF EVIDENCE

III.

Outcomes of surgical repair of a single digital nerve in adults

Current standard management of a cut digital nerve is end-to-end microsurgical nerve coaptation where possible. A recent systematic review of adult digital nerve injuries that were either repaired or left unrepaired showed that the evidence for good nerve recovery or improved function following nerve repair is poor. In the 30 studies included, only 24% of repaired nerves regained sensory recovery close to or equivalent to estimated pre-injury levels. Neuroma rates were the same in those nerves repaired (4.6%) and those not repaired (5%). Questions under debate include proper assessment methods of outcomes, decision making for repair or no repair to different fingers or the thumb, levels of injury, age, and hand dominance. This review summarizes the major evidence available and debates the surgical dogma that surrounds this injury.

Outcome of surgical repair of adult digital nerve injury: a systematic review

OBJECTIVES

A systematic review to assess the evidence supporting surgical repair of digital nerve injury versus no repair in adults in terms of clinical outcomes.

DESIGN

A Preferred Reporting Items for Systematic Reviews and Meta-Analyses-compliant systematic review with methodology based on the Cochrane Handbook of Systematic Reviews of Interventions.

DATA SOURCES

Databases included OvidMEDLINE, EMBASE, AMED, clinicaltrials.gov and the Cochrane Database of Systematic Reviews, searched from inception until 10 November 2018.

ELIGIBILITY CRITERIA

Adult digital nerve injury in which either direct repair or no repair was undertaken and an outcome measure was recorded.

DATA EXTRACTION AND SYNTHESIS

Study data extracted included demographics, injury type and extent, timing, treatment details, outcome data and time points, adverse outcomes, hand therapy and return to work. The National Institute of Health quality assessment tool for case series was used to assess risk of bias.

RESULTS

Thirty studies were included. One compared surgical repair with non-repair. All studies were case series of between 15 and 110 nerve injuries, with heterogeneous patient, injury and treatment characteristics. Two studies detailed nerve repair without magnification. Static 2-point discrimination (s2PD) was the most commonly reported outcome measure. Return of protective sensation was achieved in most cases in the nerve repair and no nerve repair groups. Repair resulted in better s2PD than no repair, but <25% repaired nerves achieved normal levels. Adverse outcomes were similar between repair and no repair groups.

CONCLUSIONS

Only level IV evidence is available to support surgical repair of digital nerves in adults. Return of normal sensibility is uncommon and almost all unrepaired nerves regained protective sensation by 6 months and all patients declined further surgery. There was no difference in adverse outcomes. There is currently a lack of high-quality evidence to support surgical repair of digital nerve injuries in adults and further research is needed.

PROSPERO REGISTRATION NUMBER

CRD42017065092.

Tactile sensitivity thresholds for the radial hemi-pulp of the index: A comparison between the Semmes-Weinstein and Cochet-Bonnet tests in 25 healthy subjects

The purpose of this work was to determine whether the Cochet-Bonnet (CB) corneal sensitivity test has a lower cutaneous pulp sensitivity threshold than the Semmes-Weinstein (SW) monofilament test. Tactile sensitivity thresholds for the radial hemi-pulp of the index finger of 25 healthy adult subjects aged 30 years on average were measured using SW and CB esthesiometers. The sensitivity threshold of the radial hemi-pulp of the index was lower with the CB test than with the SW test. The sensitivity and specificity of the CB test on palm wounds still needs to be determined to rule out nerve damage.

Fibrin Glue Increases the Tensile Strength of Conduit-Assisted Primary Digital Nerve Repair

BACKGROUND

An ideal peripheral nerve repair construct does not currently exist. Our primary goal was to determine whether fibrin glue adds to the tensile strength of conduit-assisted primary digital nerve repairs. Our secondary goal was to evaluate the impact of varying suture number and location on the tensile strength.

METHODS

Ninety cadaveric digital nerves were harvested and divided equally into the following repair groups: A (4/4), B (2/2), C (0/2), D (0/1), and E (0/0) with the first number referring to the number of sutures at the coaptation and the second number referring to the number of sutures at each proximal and distal end of the nerve-conduit junction. When fibrin glue was added, the group was labeled prime. The nerve specimens were transected and then repaired with 8-0 nylon suture and conduit. The tensile strength of the repairs was tested, and maximum failure load was determined. The results were analyzed with a 2-way analysis of variance. The Tukey post hoc test compared repair groups if the 2-way analysis of variance showed significance.

RESULTS

Both suture group and glue presence significantly affected the maximum failure load. Increasing the number of sutures increased the maximum failure load, and the presence of fibrin glue also increased the failure load.

CONCLUSIONS

Fibrin glue was found to increase the strength of conduit-assisted primary digital nerve repairs. Furthermore, the number of sutures correlated to the strength of the repair. Fibrin glue may be added to a conduit-assisted primary digital nerve repair to maintain strength and allow fewer sutures at the primary coaptation site.

Nerve injuries to the volar aspect of the hand: A comparison of the reliability of the Weber static test versus the gauze test

When examining lacerations to the volar aspect of the hand a gauze test may usually be performed to detect nerve injuries. However, published literature suggests that its sensitivity and specificity are lower than 100%. The aim of this study was to determine whether a Weber static (main hypothesis) and dynamic test or a Semmes-Weinstein test (secondary hypotheses) could be a more reliable test than the gauze test to rule out any nerve injury and avoid unnecessary wound explorations. Our case series included a total of 102 patients presenting with 123 palmar lacerations and 158 nerve injuries. On arrival at the emergency department, every patient was tested for epicritic sensation at the pulp of the injured and contralateral fingers with the Weber static and dynamic tests and the Semmes-Weinstein monofilament test. All lacerations underwent exploration under anesthetic to rule out nerve injury. The sensitivities of the gauze test, the Weber static test, the Weber dynamic test and the Semmes Weinstein monofilament test were proven to be 82.5%, 98.6%, 97.9% and 86.7% respectively. The specificities of the gauze test, the Weber static test, the Weber dynamic test and the Semmes Weinstein monofilament test were 79%, 79%, 79% and 78.9% respectively. Examination of lacerations to the volar aspect of the hand to rule out any nerve injuries should include a Weber static test instead of a gauze test. A negative Weber static test should not however discourage a surgical exploration of the laceration to rule out tendinous or vascular injury.

Recovery of mechanical detection thresholds after direct digital nerve repair versus conduit implantation

The purpose of this study was to assess sensory and functional nerve recovery after digital nerve injury in patients with an end-to-end suture (S) or with implantation of a collagen conduit (C) to bridge a nerve gap. Fifteen S and 11 C with a follow-up of 6-36 months and 28 healthy control participants were enrolled. Methods of assessments were quantitative sensory testing, the Disabilities of the Arm, Shoulder and Hand questionnaire (DASH), range of motion and the painDetect questionnaire. After both procedures, sensory profiles showed largely recovered function of C and Aδ fibres but severe loss of Aβ-fibre function leading to increased mechanical detection thresholds. There was only minimal allodynia. Severe pain was absent. Patients with conduits reported more functional impairment, especially in work performance, which correlated with the assessed loss of Aß-fibre function.

LEVEL OF EVIDENCE

III.

A novel therapy to promote axonal fusion in human digital nerves

BACKGROUND

Peripheral nerve injury can have a devastating impact on our military and veteran population. Current strategies for peripheral nerve repair include techniques such as nerve tubes, nerve grafts, tissue matrices, and nerve growth guides to enhance the number of regenerating axons. Even with such advanced techniques, it takes months to regain function. In animal models, polyethylene glycol (PEG) therapy has shown to improve both physiologic and behavioral outcomes after nerve transection by fusion of a portion of the proximal axons to the distal axon stumps. The objective of this study was to show the efficacy of PEG fusion in humans and to retrospectively compare PEG fusion to standard nerve repair.

METHODS

Patients with traumatic lacerations involving digital nerves were treated with PEG after standard microsurgical neurorrhaphy. Sensory assessment after injury was performed at 1 week, 2 weeks, 1 month, and 2 months using static two-point discrimination and Semmes-Weinstein monofilament testing. The Medical Research Council Classification (MRCC) for Sensory Recovery Scale was used to evaluate the level of injury. The PEG fusion group was compared to patient-matched controls whose data were retrospectively collected.

RESULTS

Four PEG fusions were performed on four nerve transections in two patients. Polyethylene glycol therapy improves functional outcomes and speed of nerve recovery in clinical setting assessed by average MRCC score in week 1 (2.8 vs 1.0, p = 0.03). At 4 weeks, MRCC remained superior in the PEG fusion group (3.8 vs 1.3, p = 0.01). At 8 weeks, there was improvement in both groups with the PEG fusion cohort remaining statistically better (4.0 vs 1.7, p = 0.01).

CONCLUSION

Polyethylene glycol fusion is a novel therapy for peripheral nerve repair with proven effectiveness in animal models. Clinical studies are still in early stages but have had encouraging results. Polyethylene glycol fusion is a potential revolutionary therapy in peripheral nerve repair but needs further investigation.

LEVEL OF EVIDENCE

Therapeutic study, level IV.

Does crossover innervation really affect the clinical outcome? A comparison of outcome between unilateral and bilateral digital nerve repair

Digital nerve injuries are the mostly detected nerve injury in the upper extremity. However, since the clinical phenomenon of crossover innervation at some degree from uninjured digital nerve to the injured side occurs after digital nerve injuries is sustained, one could argue that this concept might even result in the overestimation of the outcome of the digital nerve repair. With this knowledge in mind, this study aimed to present novel, pure, focused and valuable clinical data by comparing the outcomes of bilateral and unilateral digital nerve repair. A retrospective review of 28 fingers with unilateral or bilateral digital nerve repair using end-to-end technique in 19 patients within 2 years was performed. Weber's two-point discrimination, sharp/dull discrimination, warm/cold sensation and Visual Analog Scale scoring were measured at final 12-month follow ups in all patients. There was no significant difference in recovery of sensibility after unilateral and bilateral digital nerve repairs. Though there is crossover innervation microscopically, it is not important in the clinical evaluation period. According to clinical findings from this study, crossover innervations appear to be negligible in the estimation of outcomes of digital neurorrhaphy.

Inter- and intra-tester reliability of sensibility testing in digital nerve repair

The aim of this study was to investigate the inter- and intra-tester reliability of the static two-point discrimination and Semmes-Weinstein monofilament tests in digital nerve repair. A total of 100 digital nerves from 67 patients were included into the study. An experienced orthopaedic surgeon and a physiotherapist examined the sensory nerve recovery. The reproducibility score of both tests was at a poor level, but the reliability of the Semmes-Weinstein monofilament test was higher than the static two-point discrimination test. These tests should not be used alone in the quantitative monitoring of sensory recovery, but should be interpreted with the clinical findings.Level 3 non-randomized controlled study.