Limited Nerve Regeneration across Acellular Nerve Allografts (ANAs) Coincides with Changes in Blood Vessel Morphology and the Development of a Pro-Inflammatory Microenvironment.

The use of acellular nerve allografts (ANAs) to reconstruct long nerve gaps (>3 cm) is associated with limited axon regeneration. To understand why ANA length might limit regeneration, we focused on identifying differences in the regenerative and vascular microenvironment that develop within ANAs based on their length. A rat sciatic nerve gap model was repaired with either short (2 cm) or long (4 cm) ANAs, and histomorphometry was used to measure myelinated axon regeneration and blood vessel morphology at various timepoints (2-, 4- and 8-weeks). Both groups demonstrated robust axonal regeneration within the proximal graft region, which continued across the mid-distal graft of short ANAs as time progressed. By 8 weeks, long ANAs had limited regeneration across the ANA and into the distal nerve (98 vs. 7583 axons in short ANAs). Interestingly, blood vessels within the mid-distal graft of long ANAs underwent morphological changes characteristic of an inflammatory pathology by 8 weeks post surgery. Gene expression analysis revealed an increased expression of pro-inflammatory cytokines within the mid-distal graft region of long vs. short ANAs, which coincided with pathological changes in blood vessels. Our data show evidence of limited axonal regeneration and the development of a pro-inflammatory environment within long ANAs.

Multiple sessions of therapeutic electrical stimulation using implantable thin-film wireless nerve stimulators improve functional recovery after sciatic nerve isograft repair.

INTRODUCTION/AIMS: Although therapeutic electrical stimulation (TES) of injured peripheral nerve promotes axon regeneration and functional recovery, clinical applications of this therapy are limited to the intraoperative timeframe. Implantable, thin-film wireless nerve stimulators offer a potential solution to this problem by enabling delivery of electrical stimuli to an injured nerve over a period of several days post-surgery. The aim of this study was to determine the optimal time course of stimulation for maximizing functional recovery in a rat sciatic nerve isograft repair model. METHODS: Adult male Lewis rats underwent thin-film wireless nerve stimulator implantation following sciatic nerve transection and 40 mm nerve isograft repair. Immediately after surgery, animals began a daily regimen of TES for up to 12 consecutive days. Functional recovery was assessed by compound muscle action potential (CMAP), evoked muscle force, wet muscle mass, and axon counting. RESULTS: Serial CMAP measurements increased in amplitude over the course of the study, yet no significant difference between cohorts for serial or terminal CMAPs was observed. Axon counts and wet muscle mass measurements were greatest in the 6-day stimulation group, which correlated with a significant increase in evoked muscle force for the 6-day stimulation group at the terminal time point. DISCUSSION: Six daily sessions of TES were found to be most effective for augmenting functional recovery compared to other time courses of stimulation. Future studies should incorporate additional subjects and track axonal sprouting or measure neurotrophin levels during the therapeutic window to further elucidate the mechanisms behind, and ideal amount of, TES.

Spider silk erectile nerve reconstruction in robot-assisted radical prostatectomy: a first-in-men feasibility analysis.

PURPOSE: To investigate the safety and feasibility of spider silk interposition for erectile nerve reconstruction in patients undergoing robotic radical prostatectomy (RARP). METHODS: The major-ampullate-dragline from Nephila edulis was used for spider silk nerve reconstruction (SSNR). After removal of the prostate with either uni- or bilateral nerve-sparing, the spider silk was laid out on the site of the neurovascular bundles. Data analysis included inflammatory markers and patient reported outcomes. RESULTS: Six patients underwent RARP with SSNR. In 50% of the cases, only a unilateral nerve-sparing was performed, bilateral nerve-sparing could be performed in three patients. Placement of the spider silk conduit was uneventful, contact of the spider silk with the surrounding tissue was mostly sufficient for a stable connection with the proximal and distal ends of the dissected bundles. Inflammatory markers peaked until postoperative day 1 but stabilized until discharge without any need for antibiotic treatment throughout the hospital stay. One patient was readmitted due to a urinary tract infection. Three patients reported about erections sufficient for penetration after three months with a continuous improvement of erectile function both after bi- and unilateral nerve-sparing with SSNR up to the last follow-up after 18 months. CONCLUSION: In this analysis of the first RARP with SSNR, a simple intraoperative handling without major complications was demonstrated. While the series provides evidence that SSNR is safe and feasible, a prospective randomized trial with long-term follow-up is needed to identify further improvement in postoperative erectile function due to the spider silk-directed nerve regeneration.

Surgical management and final outcomes of chondrosarcoma of the temporomandibular joint: case series and comprehensive literature review.

BACKGROUND: Surgical management for chondrosarcoma of the temporomandibular joint (TMJ) is challenging due to the anatomical location involving the facial nerve and the functional joint. The purpose of this case series was to analyze the largest number of TMJ chondrosarcoma cases reported from a single institution and to review the literature about chondrosarcoma involving the TMJ. METHODS: Ten TMJ chondrosarcoma patients at Seoul National University Dental Hospital were included in this study. Radiographic features, surgical approaches, histopathologic subtypes, and treatment modalities were evaluated. All case reports of TMJ chondrosarcoma published in English from 1954 to 2021 were collected under PRISMA guidelines and comprehensively reviewed. RESULTS: The lesions were surgically resected in all 10 patients with efforts to preserve facial nerve function. Wide excision including margins of normal tissue was performed to ensure adequate resection margins. All TMJs were reconstructed with a metal condyle except one, which was reconstructed with vascularized costal bone. At last follow-up, all patients were still alive, and there had been no recurrence. Among 47 cases (patients from the literature and our cases), recurrence was specified in 43 and occurred in four (9.5%). CONCLUSIONS: For surgical management of TMJ chondrosarcoma, wide excision must consider preservation of the facial nerve. Reconstruction using a metal condyle prosthesis and a vascularized free flap is reliable. A more conservative surgical approach correlates with a favorable prognosis for facial nerve recovery. Nevertheless, wide excision is imperative to prevent tumor recurrence. In cases in which the glenoid fossa is unaffected by the tumor, it is deemed unnecessary to reconstruct the glenoid fossa within an oncological setting.

Surgical management of peroneal nerve injuries.

BACKGROUND: Traumatic peroneal nerve injuries are typically associated with high-energy injuries. The aim of this study was to evaluate the demographics and outcomes following surgical management of peroneal nerve injuries. METHODS: Patients evaluated at a single institution with peroneal nerve injuries between 2001 and 2022 were retrospectively reviewed. Mechanism of injury, time to surgery, pre- and postoperative examinations, and operative reports were recorded. Satisfactory outcome, defined as the ability to achieve anti-gravity dorsiflexion strength or stronger following surgery, was compared between nerve grafting and nerve transfers in patients with at least 9 months of postoperative follow-up. RESULTS: Thirty-seven patients had follow-up greater than 9 months after surgery, with an average follow-up of 3.8 years. Surgeries included neurolysis (n=5), direct repair (n=2), tibial motor nerve fascicle transfer to the anterior tibialis motor branch (n=18), or interposition nerve grafting using sural nerve autograft (n=12). At last follow-up, 59.5% (n=22) of patients had anti-gravity strength or stronger dorsiflexion. Nineteen (51.4%) patients used an ankle-foot orthosis during all or some activities. In patients that underwent nerve grafting only across the peroneal nerve defect, 44.4% (n=4) were able to achieve anti-gravity strength or stronger dorsiflexion. In patients that had a tibial nerve fascicle transfer to the tibialis anterior motor branch of the peroneal nerve, 42.9% (n=6) were able to achieve anti-gravity strength or stronger dorsiflexion at last follow-up. There was no statistical difference between nerve transfers and nerve grafting in postoperative dorsiflexion strength (p = 0.51). CONCLUSION: Peroneal nerve injuries frequently occur in the setting of knee dislocations and similar high-energy injuries. Nerve surgery is not universally successful in restoration of ankle dorsiflexion, with one-third of patients requiring an ankle-foot orthosis at mid-term follow-up. Patients should be properly counseled on the treatment challenges and variable outcomes following peroneal nerve injuries.

Cochlear implantation and facial nerve anastomosis to rehabilitate a burnt middle ear.

A 48-year-old man presented to the ENT department of a general hospital after a traumatic event that occurred at work. During arc welding, an incandescent metallic projectile entered the left external auditory canal immediately causing earache, tinnitus, hearing loss, vertigo, and completed peripheral facial palsy on the left side. A burnt middle ear is a rare situation for which very few cases are described in the literature. We describe and discuss our therapeutic strategy in an emergency setting. This can be of interest to any ENT surgeon who may face such a case of ear burn. Then we report the first repair of the facial nerve by interposition of an anastomosed intermediate graft associated with cochlear implantation during a single surgical intervention. This case illustrates the multimodal rehabilitation of the damage that can be a consequence of petrous trauma. The patient recovered hearing and facial motor skills.

At What Time Interval After a Sharp Nerve Laceration Is Primary Nerve Repair No Longer Possible?

PURPOSE: The timeframe after a sharp nerve injury when nerve grafting becomes required remains unclear. A retrospective analysis was performed to determine the timeframe when primary repair of a sharp nerve laceration can no longer be performed and grafting becomes necessary. METHODS: All sharp nerve injuries in three regions of the hands and upper extremity-major nerves, common digital nerves, and proper digital nerves-treated between 2016 and 2021 were reviewed. Time from injury to repair, need for nerve grafting, length of graft, age, and associated injuries were collected and analyzed. RESULTS: A total of 313 nerve lacerations were included. Predictors of the need for grafting included time from injury to repair and level of injury. The odds ratio of time from injury in predicting the need for grafting was 1.04 for proper digital nerves, 1.05 for common digital nerves, and 1.18 for major nerves. Age and other injuries were not associated with increased rates of grafting. Only level of injury was associated with length of graft needed. CONCLUSIONS: Patients with sharp major nerve injuries required grafting more frequently after several days from injury, whereas primary repair of common and proper digital nerves could be achieved up to two weeks or greater after injury. This suggests that the window for primary neurorrhaphy may be as short as two days after injury for major nerve injuries, much shorter than for common and proper digital nerve injuries. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic IV.

Staged Phrenic Nerve Elongation and Free Functional Gracilis Muscle Transplantation-A Possible Option for Late Reconstruction in Chronic Brachial Plexus Injury.

PURPOSE: In patients with late brachial plexus birth injuries, sequelae after acute flaccid myelitis, or chronic adult brachial plexus injury, donor nerves for functioning muscle transplantation are often scarce. We present the results of a potential strategy using the phrenic nerve with staged free gracilis transplantation for upper extremity reanimation in these scenarios. METHODS: A retrospective review was performed on an institutional database of brachial plexus injury or patients with palsy. All patients underwent a staged reconstruction in which the ipsilateral phrenic nerve was extended by an autogenous nerve graft (PhNG), followed by free-functioning gracilis transplantation (PhNG-gracilis). RESULTS: Nine patients (6 cases of late brachial plexus birth injuries, 2 of acute flaccid myelitis, and 1 of adult chronic brachial plexus injury) were included in this study. The median follow-up period following the PhNG-gracilis procedure was 27 months (range, 12-72 months). The goals of the staged PhNG and PhNG-gracilis were primarily finger extension or finger flexion. In some patients, the technique was used to improve both elbow and finger function, tunneling the muscle through the flexor compartment of the upper arm and under the mobile wad at the elbow. All patients exhibited improvement of muscle strength, including in finger extension (4 patients) from M0 to M2; finger flexion (3 patients) from M0 to M3; elbow extension (1 patient) from M0 to M2; and elbow flexion (1 patient) from M2 to M4. CONCLUSIONS: A 2-stage PhNG-gracilis may restore or enhance the residual elbow and/or finger paralysis in chronic brachial plexus injuries. A minimum follow-up period of 3 years is recommended. This technique may remain useful as one of the last reconstructive options to increase power in patients with scarce donor nerves. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic V.

A Multicenter Prospective Randomized Comparison of Conduits Versus Decellularized Nerve Allograft for Digital Nerve Repairs.

PURPOSE: While there are advantages and disadvantages to both processed nerve allografts (PNA) and conduits, a large, well-controlled prospective study is needed to compare the efficacy and to delineate how each of these repair tools can be best applied to digital nerve injuries. We hypothesized that PNA digital nerve repairs would achieve superior functional recovery for longer length gaps compared with conduit-based repairs. METHODS: Patients (aged 18-69 years) presenting with suspected acute or subacute (less than 24 weeks old) digital nerve injuries were recruited to prticipate at 20 medical centers across the United States. After stratification to short (5-14 mm) and long (15-25 mm) gap subgroups, the patients were randomized (1:1) to repair with either a commercially available PNA or collagen conduit. Baseline and outcomes assessments were obtained either before or immediately after surgery and planned at 3-, 6-, 9-, and 12-months after surgery. All assessors and patients were blinded to the treatment arm. RESULTS: In total, 220 patients were enrolled, and 183 patients completed an acceptable last evaluable visit (at least 6 months and not more than 15 months postrepair). At last follow-up, for the short gap repair groups, average static two-point discrimination was 7.3 ± 2.8 mm for PNA and 7.5 ± 3.1 mm for conduit repairs. For the long gap group, average static two-point discrimination was significantly lower at 6.1 ± 3.3 mm for PNA compared with 7.5 ± 2.4 mm for conduit repairs. Normal sensation (American Society for Surgery of the Hand scale) was achieved in 40% of PNA long gap repairs, which was significantly more than the 18% observed in long conduit patients. Long gap conduits had more clinical failures (lack of protective sensation) than short gap conduits. CONCLUSIONS: Although supporting similar levels of nerve regeneration for short gap length digital nerve repairs, PNA was clinically superior to conduits for long gap reconstructions. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic I.

The surgical anatomy of the axillary approach for nerve transfer procedures targeting the axillary nerve.

PURPOSE: The exact relational anatomy for the anterior axillary approach, targeting the axillary nerve for nerve transfers/grafts, has not been fully investigated. Therefore, this study aimed to dissect and document the gross anatomy surrounding this approach, specifically regarding the axillary nerve and its branches. METHODS: Fifty-one formalin-fixed cadavers (98 axilla) were bilaterally dissected simulating the axillary approach. Measurements were taken to quantify distances between identifiable anatomical landmarks and relevant neurovascular structures encountered during this approach. The musculo-arterial triangle, described by Bertelli et al., to aid in identification on localization of the axillary nerve, was also assessed. RESULTS: From the origin of the axillary nerve till (1) latissimus dorsi was 62.3 ± 10.7 mm and till (2) its division into anterior and posterior branches was 38.8 ± 9.6 mm. The origin of the teres minor branch along the posterior division of the axillary nerve was recorded as 6.4 ± 2.9 mm in females and 7.4 ± 2.8 mm in males. The musculo-arterial triangle reliably identified the axillary nerve in only 60.2% of the sample. CONCLUSION: The results clearly demonstrate that the axillary nerve and its divisions can be easily identified with this approach. The proximal axillary nerve, however, was situated deep and therefore challenging to expose. The musculo-arterial triangle was relatively successful in localising the axillary nerve, however, more consistent landmarks such as the latissimus dorsi, subscapularis, and quadrangular space have been suggested. The axillary approach may serve as a reliable and safe method to reach the axillary nerve and its divisions, allowing for adequate exposure when considering a nerve transfer or graft.

Axonal Regeneration Through Autologous Grafts: Does the Axonal Load Influence Regeneration?

INTRODUCTION: Two-stage free functional muscle transfers for long-standing facial palsy can yield unpredictable results. Earlier studies have demonstrated incomplete regeneration across neurorrhaphies in native nerve and higher donor axonal counts correlating with improved outcomes but axonal count in nerve grafts have not been as thoroughly reviewed. To investigate the impact of varying axonal counts in autologous grafts on functional outcomes of repair. MATERIALS AND METHODS: Animals were allocated into three groups: Direct Nerve Repair (DNR, n = 50), Small Nerve Graft (SNG, n = 50), and Large Nerve Graft (LNG, n = 50). All grafts were inset into the Posterior Auricular Nerve with ear movement recovery (EMR) monitored as functional outcome. At various postoperative weeks (POWs), excised specimens were imaged with electron microscopy. Axonal counts were measured proximal to, distal (DAC) to, and within grafts. Total Success Ratio (TSR) was calculated. RESULTS: In DNR, DAC was significantly lower than proximal axonal counts at all POWs, with maximum TSR of 80%. TSR for LNG and SNG were significantly lower at all POWs when compared to DNR, with maximums of 56% and 38%, respectively. LNG had a significantly larger DAC than SNG at POW12 and beyond. A direct relationship was present between DAC and EMR for all values. CONCLUSIONS: Higher native axonal count of autologous nerve grafts resulted in higher percentage of regeneration across neurorrhaphies.

Facial nerve sacrifice in lateral approaches to the skull base: Simultaneous reconstruction by graft interposition.

PURPOSE: To evaluate the outcome of facial nerve (FN) cable graft interposition in lateral skull base surgery. MATERIALS AND METHODS: A group of 16 patients who underwent FN graft interposition procedure was retrospectively considered. Postoperative FN function was evaluated using the House-Brackmann (HB) grading system, the Sunnybrook Facial Grading System (SFGS), the Facial Disability Index (FDI) and the Oral Functioning Scale (OFS) questionnaires. RESULTS: 56.2% of patients had a good postoperative FN outcome (HB grade II-III). Postoperative electromyography (EMG) showed re-innervation potentials in 60% of patients; median age of these patients was significantly lower compared to who did not manifest re-innervation (p = 0.039). CONCLUSION: FN primary reconstruction remains the advisable rehabilitative option when the nerve is interrupted during lateral skull base surgeries, allowing to satisfactory postoperative results in more than half of patients. EMG confirmed the restoring of nerve conduction and it was more frequent in younger patients. The SFGS, the FDI and the OFS are important tools especially in the setting of a rehabilitation program.

Nerve merging repair in the replantation of a severed limb with defects in multiple nerves: five cases and long-term follow-up.

BACKGROUND: Repairing all nerves is challenging in cases of upper arm avulsion combined with defects in multiple nerves because the donor area for autogenous nerve transplantation is limited and the outcomes of long-segment allogeneic nerve transplantation are poor. Based on the principle of magnified nerve regeneration, we present a method called nerve merging repair, the feasibility of which needs to be confirmed in clinical practice. METHODS: The nerve merging repair method relies on the use of fewer proximal nerves to innervate more distal nerves and depends mainly on whether the radial nerve (RN) can repair itself. In the case of defects in multiple nerves precluding RN self-repair, median-(median + radial) (M-(M + R)) repair is performed. If the RN can undergo self-repair, median-(median + ulnar) (M-(M + U)) or ulnar-(ulnar + median) (U-(U + M)) is used to repair the three nerves. Five cases were included in the study and involved the analysis of joint motor function, muscle strength and sensory recovery of the affected limb. RESULTS: The replanted limb survived in all 5 cases. Follow-up visits were conducted with the patients for 51-80 months, during which they experienced satisfactory recovery of skin sensation, elbow flexion and extension and partial recovery of hand muscle strength. CONCLUSIONS: To a certain extent, treatment with the nerve merging repair method improved the sensory and motor function of the affected limb and limited the loss of function of the donor nerve area. This intervention provides a new approach for repairing long-segment defects in multiple nerves caused by avulsion amputation of the upper limb.

A comprehensive review of the great auricular nerve graft.

The great auricular nerve (GAN) is a superficial branch of the cervical plexus that innervates parts of the mandible, auricle, and earlobe. Over the past 30 years, the GAN has become the nerve graft donor of choice for many surgeons for reconstructing injured facial nerves. In this review, we discuss the anatomy and function of the GAN, while focusing on surgical landmarks and the characteristics that make it a suitable nerve graft donor. In addition, we present and summarize published case reports on use of the GAN for grafting. We hope that this review will provide surgeons with an up-to-date and concise reference.

Relocating the C5 nerve stump in C5 nerve grafting to prevent iatrogenic phrenic nerve injury.

BACKGROUND: Exploration and grafting of the brachial plexus remains the gold standard for post-ganglionic brachial plexus injuries that present within an acceptable time frame from injury. The most common nerves available for grafting include C5 and C6. During the surgical exposure of C5 and C6, the phrenic nerve is anatomically anterior to the cervical spinal nerves, making it vulnerable to injury while performing the dissection and nerve stump to graft coaptation. We describe a novel technique that protects the phrenic nerve from injury during supraclavicular brachial plexus exposure and grafting of C5 or upper trunk ruptures or neuromas in-continuity. METHODS: A 4-step technique is illustrated: (1) The normal anatomic relationships of the phrenic nerve anterior to C5 is displayed in the face of the traumatic scarring. (2) The C5 spinal nerve stump is then transposed from its anatomic position posterior to the phrenic nerve to an anterior position. (3) The C5 stump is then moved medially for retrograde neurolysis of C5 from its phrenic nerve contribution. The graft coaptation to C5 is performed in this medial position, which minimizes retraction of the phrenic nerve. (4) The normal anatomic relationship of the phrenic nerve and the C5 nerve graft is restored. RESULTS: We have been routinely relocating the C5 spinal nerve stump around the phrenic nerve for the past 10 years. We have experienced no adverse respiratory events. CONCLUSION: This technique facilitates surgical exposure and prevents iatrogenic injury on the phrenic nerve during nerve reconstruction.

"All in One or (W)hole in One Repair" for Adult Total Brachial Plexus Palsy.

Background Total brachial plexus palsy (TBPP) accounts for nearly 50% of all brachial plexus injuries. Since achieving a good functional hand was almost impossible, the aim was settled to get a good shoulder and elbow function. It was Gu, who popularized the concept of utilizing contralateral C7 (CC7) with vascularized ulnar nerve graft (VUNG) to get some hand function. We have modified it to suit our patients by conducting it as a single-stage procedure, thereby trying to get a functional upper limb. Methods From 2009 to 2014, we had 20 TBPP patients. We feel nerve reconstruction is always better than any other salvage procedure, including free muscle transfer. We modified Gu's concept and present our concept of total nerve reconstruction as "ALL IN ONE OR (W)HOLE IN ONE REPAIR." Results All patients able to move their reconstructed limbs independently or with the help of contralateral limbs. Three patients developed hook grip and one patient was able to incorporate limbs to do bimanual jobs. One important observation is that all the reconstructed limbs regain the bulk, and to a certain extent, the attitude and appearance looks normal, as patients no longer hide it or hang it in a sling. Conclusion Adult brachial plexus injury itself is a devastating injury affecting young males. By doing this procedure, the affected limb is not dissociated from the rest of the body and rehabilitation can be aimed to get a supportive limb.

Comparison of SB-SDS and other decellularization methods for the acellular nerve graft: Biological evaluation and nerve repair in vitro and in vivo.

We aimed to compare the performance of acellular nerves prepared by different decellularization methods, screening out the optimal decellularization protocol, repairing the sciatic nerve defects in rats by the allogeneic transplantation, and evaluating the effect of regenerative nerve on the function reconstruction. The Sondell, SB-SDS, TnBP, and the high/low permeation methods were used to decellularize donor nerves. Nerves without any treatment were as the control group. The histological results were evaluated by HE staining and toluidine blue (TB) staining. The proliferation activity of L929 cells was detected by CCK-8 assay. The adhesion of Schwann cells was observed and quantified by SEM. Balb/c mice were used to evaluate the cellular and humoral immunogenicity of the nerve scaffolds. The rat sciatic nerve defect model was applied to observe the repair effect of acellular nerve scaffold in vivo. To SB-SDS group, it remained the original state of the nerves, with no observed nucleus and axons, the neurotoxicity grade detected by CCK-8 being almost 0, and it kept the largest number of Schwann cells adhered to the acellular nerve and the better morphology. Further, it showed that the selected SB-SDS rats acellular nerve scaffold could promote the nerve repair of the rats by HE staining and TB staining. We could conclude that the acellular nerve matrix prepared by the SB-SDS method effectively removes the cellular components in the nerve tissue and retains the main components of the extracellular matrix of the nerve tissue, whose rats decellularized nerve scaffold could promote the sciatic nerve repair better.

Pathological Findings of Hourglass-Like Constriction in Spontaneous Posterior Interosseous Nerve Palsy.

We report the pathological findings of hourglass-like fascicular constriction (HLFC) under optical and electron microscopy. A 24-year-old man with spontaneous posterior interosseous nerve palsy was treated by interfascicular neurolysis at 29 weeks after onset. One fascicle in the radial nerve presented severe HLFC with torsion at 5 cm proximal to the elbow. Functional recovery was achieved by resection of the enlarged fascicle including HLFC and sural nerve grafting. Proximal to the HLFC, the endoneurium was filled with clusters of regenerating nerve fibers. At the level of the HLFC, a complete loss of myelinated nerve fibers and vascular occlusion of endo- and perineurial vessels were found. Few regenerating nerve fibers were observed. Distal to the HLFC, severe endoneurial edema, a complete loss of myelinated and unmyelinated nerve fibers, and bands of Büngner were noted. These electron microscopic findings demonstrated a detailed pathology of the nerve around the HLFC.

Outcomes of Late Microsurgical Nerve Reconstruction for Brachial Plexus Birth Injury.

PURPOSE: Microsurgical nerve reconstruction has been advocated between 3 and 9 months of life in select patients with brachial plexus birth injury (BPBI), yet some patients undergo indicated surgery after this time frame. Outcomes in these older patients remain poorly characterized. We analyzed outcomes of nerve reconstruction performed after 9 months of age and hypothesized that (1) Active Movement Scale (AMS) scores improve after surgery, and (2) there are no differences in AMS scores between patients undergoing nerve transfers versus those undergoing nerve grafting. METHODS: From 2000 to 2014, 750 patients at 6 U.S. centers were prospectively enrolled in a multicenter database. We included patients treated with nerve reconstruction after 9 months of age with minimum 12 months' follow-up. Patients were evaluated using AMS scores. To focus on the results of microsurgery, only outcomes prior to secondary surgery were analyzed. We analyzed baseline variables using bivariate statistics and change in AMS scores over time and across treatment groups using linear mixed models. RESULTS: We identified 32 patients (63% female) with median follow-up of 29.8 months. Median age at microsurgery was 11.2 months. Twenty-five (78%) had an upper trunk injury. Compared with before surgery, total AMS scores improved modestly at 1 year and 2 or more years follow-up. At 1 year follow-up, AMS scores improved for shoulder function (abduction, external rotation) and elbow flexion. Between-group comparisons found no differences in total AMS scores or AMS subscales between graft and transfer groups at 1 year or 2 or more years after surgery, so we cannot recommend one strategy over the other based on our findings. CONCLUSIONS: Overall, nerve reconstruction in patients with BPBI after 9 months of age resulted in improved function over time. There was no difference in outcomes between nerve transfer and nerve graft groups and 1 or 2 or more years follow-up. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

A new treatment for lingual nerve injury: an anatomical feasibility study for using a buccal nerve pedicle graft.

PURPOSE: Lingual nerve (LN) palsy is a serious complication in dentistry and repaired by direct suture or a free graft technique. To our knowledge, there has been no study using a (long) buccal nerve (BN) graft as a donor for LN repair. Therefore, we aimed to clarify the location of the BN and investigate if it is feasible to reroute the BN to the LN. METHODS: Twenty-four sides from 12 fresh-frozen Caucasian cadaveric heads were used in this study. The mean age at death was 73.9 ± 13.4 years. The LN was dissected on the floor of the oral cavity medial to the third molar tooth. Next, the mucosa with the buccinator muscle, pterygomandibular raphe, and superior pharyngeal constrictor muscle on the retromolar area was retracted anteriorly to widen the pathway of the LN. Finally, the BN was cut and transposed to the LN through this widened pathway to its feasibility. RESULTS: The mean diameter of the BN and vertical distance from the horizontal part of the retromolar trigone to the BN was 1.47 ± 0.32 mm and 18.53 ± 6.21 mm, respectively. On all sides, the BN was able to be transposed to the LN without tension. CONCLUSION: Such a technique might be used for the patients with LN injury and who have lost sensation of the tongue.