Nerve injuries of the upper extremity-expected outcome and clinical examination

Does prophylactic decompression of distal nerves following nerve repair improve functional recovery? A systematic review

BACKGROUND

Peripheral nerve injuries are burdensome on healthcare systems, individuals and society as a whole. The current standard of treatment for neurotmesis is primary neurorrhaphy or nerve grafting. However, several patients do not recover their full function. There has been a suggestion that primary distal neurolysis at common entrapment sites maximises surgical outcomes; however, no guidelines exist on this practice. This scoping review aims to ascertain the existing evidence on prophylactic distal decompression of peripheral nerves following repair.

METHODS

A literature search was performed using Ovid Medline, PubMed, Embase and Cochrane Central Register of Controlled Trials and Cochrane Database of Systematic Reviews for studies published in the past 50 years. Studies were screened using a selection criteria and study quality was assessed using standardised tools. Furthermore, thematic content analysis was performed.

RESULTS

Six studies were eligible for inclusion after screening; all studies were retrospective and at most level 3 evidence. No studies were designed specifically to assess the efficacy of distal neurolysis following proximal repair, thus no comparative data with control cohorts are available. All studies that recommended distal decompression of proximally repaired nerves based their conclusions on cases observed by the authors in practice or from theories on nerve regeneration.

CONCLUSIONS

This systematic review suggests that the evidence on the role of immediate distal neurolysis in primary neurorrhaphy is inadequate. Recommendations are limited by the lack of large-scale and generalisable data. Further research is needed with definitive objective outcomes and patient-related outcome measures.

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.

Digital nerve injury: to repair or not?

BACKGROUND

There are very few studies comparing patients with and without repair after digital nerve injury. It is still controversial whether digital nerve repair is necessary.

AIMS

The aim of this study was to evaluate the long-term clinical outcomes of patients with unilateral isolated digital nerve injury who underwent surgical repair and those who did not.

METHODS

Seventy-four patients with unilateral digital nerve injury were included in the study. Of these, the patients who underwent surgical repair were determined as group A (n = 42), the patients without repair as group B (n = 32), and the groups were divided into subgroups according to injury levels. Results were evaluated with a minimum follow-up of 24 months.

RESULTS

When the S2PD results were evaluated overall, it was found that those who had digital nerve repair (group A) had significantly better outcomes compared to those without repair (group B) (p = 0.012). When the subgroups were evaluated according to the injury localization, no significant difference was observed at the distal levels, while it was observed that the patients who underwent repair in the proximal levels showed significantly better results (p = 0.003, p = 0.012).

CONCLUSION

In this study, it was seen that there was no difference between the results of repair and non-repair of unilateral nerve injuries distal to the middle level of the middle phalanx, but repair is required in injuries proximal to this level.

Thermoelectric Freeze-Casting of Biopolymer Blends: Fabrication and Characterization of Large-Size Scaffolds for Nerve Tissue Engineering Applications

Peripheral nerve injuries (PNIs) are detrimental to the quality of life of affected individuals. Patients are often left with life-long ailments that affect them physically and psychologically. Autologous nerve transplant is still the gold standard treatment for PNIs despite limited donor site and partial recovery of nerve functions. Nerve guidance conduits are used as a nerve graft substitute and are efficient for the repair of small nerve gaps but require further improvement for repairs exceeding 30 mm. Freeze-casting is an interesting fabrication method for the conception of scaffolds meant for nerve tissue engineering since the microstructure obtained comprises highly aligned micro-channels. The present work focuses on the fabrication and characterization of large scaffolds (35 mm length, 5 mm diameter) made of collagen/chitosan blends by freeze-casting via thermoelectric effect instead of traditional freezing solvents. As a freeze-casting microstructure reference, scaffolds made from pure collagen were used for comparison. Scaffolds were covalently crosslinked for better performance under load and laminins were further added to enhance cell interactions. Microstructural features of lamellar pores display an average aspect ratio of 0.67 ± 0.2 for all compositions. Longitudinally aligned micro-channels are reported as well as enhanced mechanical properties in traction under physiological-like conditions (37 °C, pH = 7.4) resulting from crosslinking treatment. Cell viability assays using a rat Schwann cell line derived from sciatic nerve (S16) indicate that scaffold cytocompatibility is similar between scaffolds made from collagen only and scaffolds made from collagen/chitosan blend with high collagen content. These results confirm that freeze-casting via thermoelectric effect is a reliable manufacturing strategy for the fabrication of biopolymer scaffolds for future peripheral nerve repair applications.

Detection of Traumatic and Postoperative Nerve Lesions following Upper Extremity Fractures in a Pediatric Cohort Using MR Neurography

INTRODUCTION

 Fractures of the upper extremity are common traumatic injuries in children. Nerve lesions are a rare but typical complication of these fractures. Additional to physical, electrophysiological, and sonographic examinations, magnetic resonance neurography (MRN) can be used to assess the degree and exact localization of nerve damage. This retrospective study was conducted to evaluate the potential role of this examination technique for children and to test a proposed MRN classification of traumatic nerve injury according to Chhabra in a pediatric cohort.

MATERIALS AND METHODS

 Pediatric patients undergoing MRN for traumatic nerve injury from January 2016 to December 2020 were retrospectively identified. A total of 12 consecutive patients with sufficient clinical data, an MRN, and if available follow-up examination were enrolled and analyzed.

RESULTS

 In 10 of 12 cases one or more nerve lesions could be identified by MRN using the classification proposed by Chhabra et al. MRN was used to assess nerve injuries, imaging results were compared with clinical course. Clinical follow-up examinations of 10 patients showed an overall good clinical recovery, even in one case with severe trauma and nerve surgery.

CONCLUSION

 MRN as a noninvasive procedure can help in the evaluation of nerve injury, especially for the identification of lower grade nerve damage and to objectify suspected nerve damage in case of uncertain clinical examination results; thus, can help in decision making whether surgical revision or conservative treatment is preferable.

Peripheral nerve injuries of the upper extremity in a pediatric population: outcomes and prognostic factors

Peripheral nerve injuries of the upper limb are rare in children and poorly documented. The aim of this retrospective study was to analyze long-term sensory and motor results, and to determine predictive factors for recovery after surgery. Eleven children, with a mean age at injury of 9.7 years (5-15), operated on between 2006 and 2018, were included. Sensory perception was measured on monofilament test and static 2-point discrimination test. Grip strength was measured with a dynamometer and motor strength was assessed on the Medical Research Council scale. Quality of life was assessed on QuickDASH. The injury involved the radial (n = 1), median (n = 9), or combined median and ulnar (n = 1) nerves and was repaired by primary direct suture (n = 11). The mechanism involved glass laceration (n = 10) or a road accident (n = 1). The dominant limb was involved in 7 cases. At a mean 7.7 years' follow-up, touch sensitivity was normal or slightly deficient on monofilament test. Discrimination test was normal or adequate. Strength was complete in 10 patients. Mean QuickDASH score was 5.99 (range, 0-18.18). There was no significant difference in sensory or motor recovery according to partial or complete lesion or to injury location. There was better sensory recovery in children <12 years (p < 0.05). Sensory prognosis was also better in the absence of associated lesions (p < 0.05). Sensory, motor and functional results after surgical treatment of peripheral nerve injuries of the upper limb in children were globally satisfactory. Sensory recovery was better at an early age and in the absence of associated lesions. LEVEL OF EVIDENCE: IV.

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.

Lower Extremity Combat Sustained Peripheral Nerve Injury in US Military Personnel

Background:

Since the civil war, combat sustained peripheral nerve injuries (CSPNI) have been documented during wartime. Warfare has evolved and current combat involves a greater severity of blast injuries secondary to increased use of improvised explosive devices. The purpose of this study was to describe CSPNI and report outcomes after evaluation and treatment. We hypothesize that a shorter time to evaluation will improve outcomes.

Methods:

A database including all active duty service members who sustained a CSPNI and were treated by the PNC between 2004 and 2009 was used. Service member demographic information, injury mechanism, CSPNI description, and Medical Research Council (MRC) final motor and sensory outcomes were queried from this database.

Results:

One hundred and four military service members sustained 144 PNIs. The average age was 26.7 years, and nearly all were men (98.1%). There was no correlation between Sunderland classification and age, specific PNI, injury type, or time to evaluation. Higher Sunderland classifications were found to be correlated with worse final motor (r = 0.51, P < 0.001) and final sensory (r = 0.41, P < 0.001) scores. Final motor and sensory scores were not associated with specific nerve injury, mechanism of injury, initial EMG, or surgical procedure. Shorter time to initial assessment was associated with improved final motor and sensory scores, but was not found to be statistically significant.

Conclusions:

As the complexity of CSPNIs progress as combat weaponry evolves, a firm understanding of treatment factors is important. Our study demonstrates in recent conflict that military service members’ initial injury severity is a key factor in expected outcome.

A Multicenter Matched Cohort Study of Processed Nerve Allograft and Conduit in Digital Nerve Reconstruction

PURPOSE

Biomaterials used to restore digital nerve continuity after injury associated with a defect may influence ultimate outcomes. An evaluation of matched cohorts undergoing digital nerve gap reconstruction was conducted to compare processed nerve allograft (PNA) and conduits. Based on scientific evidence and historical controls, we hypothesized that outcomes of PNA would be better than for conduit reconstruction.

METHODS

We identified matched cohorts based on patient characteristics, medical history, mechanism of injury, and time to repair for digital nerve injuries with gaps up to 25 mm. Data were stratified into 2 gap length groups: short gaps of 14 mm or less and long gaps of 15 to 25 mm. Meaningful sensory recovery was defined as a Medical Research Council scale of S3 or greater. Comparisons of meaningful recovery were made by repair method between and across the gap length groups.

RESULTS

Eight institutions contributed matched data sets for 110 subjects with 162 injuries. Outcomes data were available in 113 PNA and 49 conduit repairs. Meaningful recovery was reported in 61% of the conduit group, compared with 88% in the PNA group. In the group with a 14-mm or less gap, conduit and PNA outcomes were 67% and 92% meaningful recovery, respectively. In the 15- to 25-mm gap length group, conduit and PNA outcomes were 45% and 85% meaningful recovery, respectively. There were no reported adverse events in either treatment group.

CONCLUSIONS

Outcomes of digital nerve reconstruction in this study using PNA were consistent and significantly better than those of conduits across all groups. As gap lengths increased, the proportion of patients in the conduit group with meaningful recovery decreased. This study supports the use of PNA for nerve gap reconstruction in digital nerve reconstructions up to 25 mm.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic III.

Chronic neuropathic pain after traumatic peripheral nerve injuries in the upper extremity: prevalence, demographic and surgical determinants, impact on health and on pain medication

Background and aims Aside from the long term side effects of a nerve injury in the upper extremity with devastating consequences there is often the problem of chronic neuropathic pain. The studies concerning the prevalence of persistent pain of neuropathic origin after peripheral nerve injuries are sparse. The prevalence and risk factors associated with chronic neuropathic pain after nerve injuries in the upper extremity were assessed. Methods A standardized data collection template was employed prospectively and retrospectively for all patients with traumatic nerve injuries accepted at the Hand Surgery Department, Uppsala, Sweden between 2010 and 2018. The template included demographic data, pain diagnosis, type of injured nerve, level of injury, date of the lesion and repair, type of procedure, reoperation, time since the procedure, S-LANSS questionnaire (Self report-Leeds Assessment of Neuropathic Symptoms and Signs), RAND-36 (Item short form health survey), QuickDASH (Disability of Shoulder, Arm and Hand) and additional questionnaires concerned medication, pain intensity were sent to 1,051 patients with nerve injuries. Partial proportional odds models were used to investigate the association between persistent pain and potential predictors. Results More than half of the patients undergoing a surgical procedure developed persistent pain. Prevalence of neuropathic pain was 73% of the patients with pain (S-LANSS ≥ 12 or more). Multivariate analysis indicated that injury of a major nerve OR 1.6 (p = 0.013), years from surgery OR 0.91 (p = 0.01), younger age OR 0.7 (p < 0.001), were the main factors for predicting pain after surgery. The type of the nerve injured was the strongest predictor for chronic pain with major nerves associated with more pain (p = 0.019). Conclusions A high prevalence of chronic pain and neuropathic pain with a negative impact on quality of life and disability were found in patients after traumatic nerve injury. Major nerve injury, younger age and less time from surgery were predictors for chronic pain.

Implantation of Acellular Nerve Allograft Using Nerve Connectors

Background: Nerve connectors are short nerve conduits used to approximate nerve ends. Acellular nerve allografts are viable alternatives when direct repair is not possible but do not produce exudate essential for fibrin clot formation. We hypothesize that acellular nerve allograft implanted using nerve connectors must have end-to-end contact with the in situ nerve stumps to support nerve regeneration. Methods: Sixty Sprague Dawley rats underwent a 14-mm unilateral tibial nerve injury and subsequent repair using various combinations of acellular nerve grafts and nerve connectors. Proximal repairs for all groups utilized direct contact with the nerve stump within connector. Variations in distal repair methods (allograft length, nerve gap, and connector length) defined our 4 groups-group A: 14 mm allograft, no distal gap, and distal connector; group B: 11.5 mm allograft, 2.5 mm distal gap, and distal connector; group C: 9 mm allograft, 5 mm distal gap, and distal connector; group D: 14 mm allograft, no distal gap, and no distal connector. At 3 months post-repair, function and histomorphology were assessed. Results: Developed muscle force was significantly lower in group C (0.073 ± 0.077 N) compared with the other 3 groups (group A = 0.529 ± 0.312 N, group B = 0.461 ± 0.462 N, and group D = 0.409 ± 0.327 N). Axon counts were significantly lower in group C (2121 ± 389) compared with group A (6401 ± 855), group B (4710 ± 755), and group D (4450 ± 126). There was no statistically significant difference in G-ratios (myelination) between groups (P > .05). Conclusion: Nerve regeneration was significantly impaired as the gap distance between the distal end of the allograft and the distal nerve stump increased to 5 mm.

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.

Age does not affect the outcome after digital nerve repair in children - A retrospective long term follow up

BACKGROUND

Digital nerve injuries in children are not common, but they are considered to have an excellent prognosis, compared to adults, after nerve injury and repair. In studies including both children and adults age have been found to have an effect on outcome after nerve repair.

METHODS

We investigated in a retrospective follow up study the long-time result after digital nerve injury and repair in children, 1-16 years of age (n = 38), and evaluate if age influences outcome. A group with young children, 1-10 years of age (n = 18), was compared with a group with older children, 11-16 years of age (n = 20). A clinical evaluation to evaluate sensation and grip strength was performed and questionnaires were used [Disability of the Arm, Shoulder and Hand (DASH), Cold Sensitivity Severity Scale (CISS), VAS-function and VAS-cosmetic] in median 40 months (range 12-131 months) after the injury and repair.

RESULTS

All patient regained normal sensation. No correlations between age and monofilaments were found. Twenty children (52%) reported some problems with cold intolerance (i.e. CISS), but no other abnormal disability was found (i.e. DASH, VAS); again with no differences between the two groups.

CONCLUSIONS

Children have an excellent long-term recovery after a digital nerve repair and without any influence of age.

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.

A Multicenter, Prospective, Randomized, Pilot Study of Outcomes for Digital Nerve Repair in the Hand Using Hollow Conduit Compared With Processed Allograft Nerve

BACKGROUND

Current repair options for peripheral nerve injuries where tension-free gap closure is not possible include allograft, processed nerve allograft, and hollow tube conduit. Here we report on the outcomes from a multicenter prospective, randomized, patient- and evaluator-blinded, pilot study comparing processed nerve allograft and hollow conduit for digital nerve reconstructions in the hand.

METHODS

Across 4 centers, consented participants meeting inclusion criteria while not meeting exclusion criteria were randomized intraoperatively to either processed nerve allograft or hollow conduit. Standard sensory and safety assessments were conducted at baseline, 1, 3, 6, 9, and 12 months after reconstruction. The primary outcome was static 2-point discrimination (s2PD) testing. Participants and assessors were blinded to treatment. The contralateral digit served as the control.

RESULTS

We randomized 23 participants with 31 digital nerve injuries. Sixteen participants with 20 repairs had at least 6 months of follow-up while 12-month follow-up was available for 15 repairs. There were no significant differences in participant and baseline characteristics between treatment groups. The predominant nerve injury was laceration/sharp transection. The mean ± SD length of the nerve gap prior to repair was 12 ± 4 mm (5-20 mm) for both groups. The average s2PD for processed allograft was 5 ± 1 mm (n = 6) compared with 8 ± 5 mm (n = 9) for hollow conduits. The average moving 2PD for processed allograft was 5 ± 1 mm compared with 7 ± 5 mm for hollow conduits. All injuries randomized to processed nerve allograft returned some degree of s2PD as compared with 75% of the repairs in the conduit group. Two hollow conduits and one allograft were lost due to infection during the study.

CONCLUSIONS

In this pilot study, patients whose digital nerve reconstructions were performed with processed nerve allografts had significantly improved and more consistent functional sensory outcomes compared with hollow conduits.

Autograft Substitutes: Conduits and Processed Nerve Allografts

Manufactured conduits and allografts are viable alternatives to direct suture repair and nerve autograft. Manufactured tubes should have gaps less than 10 mm, and ideally should be considered as an aid to the coaptation. Processed nerve allograft has utility as a substitute for either conduit or autograft in sensory nerve repairs. There is also a growing body of evidence supporting their utility in major peripheral nerve repairs, gap repairs up to 70 mm in length, as an alternative source of tissue to bolster the diameter of a cable graft, and for the management of neuromas in non-reconstructable injuries.

The normal sensibility of the hand declines with age--a proclamation for the use of delta two-point discrimination values for sensibility assessment after nerve reconstruction

The scores used to evaluate sensibility after digital nerve reconstruction do not take the patient's age into consideration, although there is evidence that the outcome after digital nerve reconstruction is age-dependent. However, it is not clear if the normal sensibility of the hand is also age-dependent, as the existing studies have major limitations. We evaluated the normal sensibility of the hand in 232 patients using static and moving two-point discrimination (2PD) tests and the Semmes-Weinstein-monofilament test. We found the climax of sensibility in the third decade with age-dependent deterioration afterwards in all three tests. Mean 2PD values of the radial digital nerve of the index finger (N3) showed to be significantly lower than values of the ulnar digital nerve of the small finger (N10). To overcome shortcomings of classification systems that do not consider the patient's age and inter-individual differences, we suggest using the difference of the static 2PD values of the injured to the uninjured contralateral nerve (delta 2PD) for assessment of sensibility after digital nerve reconstruction.

Microsurgeons do better--tactile training might prevent the age-dependent decline of the sensibility of the hand

Recent data demonstrate that the normal sensibility of the hand seems to be age-dependent with the best values in the third decade and a consecutive deterioration afterwards. However, it is not clear if long-term tactile training might prevent this age-dependent decline. We evaluated sensibility of the hand in 125 surgeons aged between 26 and 75 years who perform microsurgical operations, thereby undergoing regular tactile training. We examined sensibility of the radial digital nerve of the index finger (N3) and the ulnar digital nerve of the small finger (N10) using static and moving two-point discrimination (2PD) tests and compared the results to 154 age-matched individuals without specific long-term tactile training. We found significantly lower static and moving 2PD values for the sixth, seventh, and eighth decade of life in the microsurgery group compared to the control group (p < 0.05). This study demonstrates that long-term tactile training might prevent the known age-dependent decline of the sensibility of the hand.

Optimal site for facial nerve transection and neurorrhaphy: a randomized prospective animal study

Background

Since the first facial allograft transplantation was performed, several institutions have performed the procedure with the main objectives being restoration of the aesthetic appearance and expressive function of the face. The optimal location to transect the facial nerve during flap harvest in transplantation to preserve facial movement function is currently unknown. There are currently two primary methods to perform facial nerve neurorrhaphy between the donor and recipient-one protocol involves transection and repair of the facial nerve at the main trunk while the another protocol advocates for the neurorrhaphy to be performed distally at the main branches. The purpose of this study is to establish the optimal location for transection and repair of the facial nerve to optimize functional recovery of facial movement.

Methods

A prospective randomized controlled trial using a rat model was performed. Two groups of 12 rats underwent facial nerve transection and subsequent repair either at the main trunk of the nerve (group 1) or 2 cm distally, at the main bifurcation (group 2). Primary outcome of nerve functional recovery was measured using a previously validated laser curtain model, which measured amplitude of whisking at 2, 4, and 6 post-operatively. The deflection of the laser curtain sent a digital signal that was interpreted by central computer software.

Results

At week 2 post-nerve surgery, the average amplitude observed for group 1 and 2 was 4.4 and 10.8 degrees, respectively. At week 4, group 1 showed improvement with an average amplitude of 9.7 degrees, while group 2 displayed an average of 10.2 degrees. The week 6 results showed the greatest improvement from baseline for group 1. Group 1 and 2 had average amplitudes of 17.2 and 6.9 degrees, respectively. There was no statistically significant difference between the two groups at 2, 4, and 6 weeks after facial nerve surgery (p > 0.05).

Conclusions

We found no statistical difference between these two locations of nerve repair using identical methods. Therefore, the authors recommend a single versus multiple nerve repair technique. This finding has potential implications for future facial allograft transplantations and at minimum necessitates further study with long-term follow-up data.

Factors predicting sensory and motor recovery after the repair of upper limb peripheral nerve injuries

OBJECTIVE:

To investigate the factors associated with sensory and motor recovery after the repair of upper limb peripheral nerve injuries.

DATA SOURCES:

The online PubMed database was searched for English articles describing outcomes after the repair of median, ulnar, radial, and digital nerve injuries in humans with a publication date between 1 January 1990 and 16 February 2011.

STUDY SELECTION:

The following types of article were selected: (1) clinical trials describing the repair of median, ulnar, radial, and digital nerve injuries published in English; and (2) studies that reported sufficient patient information, including age, mechanism of injury, nerve injured, injury location, defect length, repair time, repair method, and repair materials. SPSS 13.0 software was used to perform univariate and multivariate logistic regression analyses and to investigate the patient and intervention factors associated with outcomes.

MAIN OUTCOME MEASURES:

Sensory function was assessed using the Mackinnon-Dellon scale and motor function was assessed using the manual muscle test. Satisfactory motor recovery was defined as grade M4 or M5, and satisfactory sensory recovery was defined as grade S3⁺ or S4.

RESULTS:

Seventy-one articles were included in this study. Univariate and multivariate logistic regression analyses showed that repair time, repair materials, and nerve injured were independent predictors of outcome after the repair of nerve injuries (P < 0.05), and that the nerve injured was the main factor affecting the rate of good to excellent recovery.

CONCLUSION:

Predictors of outcome after the repair of peripheral nerve injuries include age, gender, repair time, repair materials, nerve injured, defect length, and duration of follow-up.

Overcoming short gaps in peripheral nerve repair: conduits and human acellular nerve allograft

Nerve conduits and acellular nerve allograft offer efficient and convenient tools for overcoming unexpected gaps during nerve repair. Both techniques offer guidance for migrating Schwann cells and axonal regeneration though utilizing very different scaffolds. The substantially greater amount of animal and clinical data published on nerve conduits is marked by wide discrepancies in results that may be partly explained by a still poorly defined critical repair gap and diameter size. The available information on acellular allografts appears more consistently positive though this tool is also hampered by a longer but also limited critical length. This article reviews the current relative literature and examines pertinent parameters for application of both acellular allograft and nerve conduits in overcoming short nerve gaps.

Sensory recovery outcome after digital nerve repair in relation to different reconstructive techniques: meta-analysis and systematic review

Good clinical outcome after digital nerve repair is highly relevant for proper hand function and has a significant socioeconomic impact. However, level of evidence for competing surgical techniques is low. The aim is to summarize and compare the outcomes of digital nerve repair with different methods (end-to-end and end-to-side coaptations, nerve grafts, artificial conduit-, vein-, muscle, and muscle-in-vein reconstructions, and replantations) to provide an aid for choosing an individual technique of nerve reconstruction and to create reference values of standard repair for nonrandomized clinical studies. 87 publications including 2,997 nerve repairs were suitable for a precise evaluation. For digital nerve repairs there was practically no particular technique superior to another. Only end-to-side coaptation had an inferior two-point discrimination in comparison to end-to-end coaptation or nerve grafting. Furthermore, this meta-analysis showed that youth was associated with an improved sensory recovery outcome in patients who underwent digital replantation. For end-to-end coaptations, recent publications had significantly better sensory recovery outcomes than older ones. Given minor differences in outcome, the main criteria in choosing an adequate surgical technique should be gap length and donor site morbidity caused by graft material harvesting. Our clinical experience was used to provide a decision tree for digital nerve repair.