Cross-Facial Nerve Grafting Used Independently in Facial Reanimation: A Narrative Review.

Importance: Cross-Facial Nerve Grafting (CFNG) for facial palsy offers potential to restore spontaneous facial expression, but specific indications and associated outcomes are limited. Updates to this technique have aided in its successful employment in select cases. This review aims to explore the context in which CFNG has been successfully utilized as a primary modality. Observations: Literature review was performed auditing all studies investigating CFNG as a primary modality, which reported outcomes. A total of 326 cases reporting outcomes for primary CFNG were included. Eye closure outcomes were 83.3% successful at ages 0-18, 77.3% successful at ages 19-40, and 57.1% successful at ages 41+. Smile outcomes were 73.7% successful at ages 0-18, 81.5% successful at ages 19-40, and 52.8% successful at ages 41+. For synkinesis, 89% of cases were considered successful; 100% successful at ages 0-18, and 78.4% successful in adults. Conclusions and Relevance: CFNG may offer return of spontaneous facial function in select cases. Higher percentages of successful outcomes are observed in younger patients, when performed in two stages, and when performed earlier from the onset of FP in cases of eye closure restoration. In the modern era, CFNG has been more commonly employed as an adjunctive procedure to other reanimation techniques.

Chitosan/PLGA-based tissue engineered nerve grafts with SKP-SC-EVs enhance sciatic nerve regeneration in dogs through miR-30b-5p-mediated regulation of axon growth.

Extracellular vesicles from skin-derived precursor Schwann cells (SKP-SC-EVs) promote neurite outgrowth in culture and enhance peripheral nerve regeneration in rats. This study aimed at expanding the application of SKP-SC-EVs in nerve grafting by creating a chitosan/PLGA-based, SKP-SC-EVs-containing tissue engineered nerve graft (TENG) to bridge a 40-mm long sciatic nerve defect in dogs. SKP-SC-EVs contained in TENGs significantly accelerated the recovery of hind limb motor and electrophysiological functions, supported the outgrowth and myelination of regenerated axons, and alleviated the denervation-induced atrophy of target muscles in dogs. To clarify the underlying molecular mechanism, we observed that SKP-SC-EVs were rich in a variety of miRNAs linked to the axon growth of neurons, and miR-30b-5p was the most important among others. We further noted that miR-30b-5p contained within SKP-SC-EVs exerted nerve regeneration-promoting effects by targeting the Sin3a/HDAC complex and activating the phosphorylation of ERK, STAT3 or CREB. Our findings suggested that SKP-SC-EVs-incorporating TENGs represent a novel type of bioactive material with potential application for peripheral nerve repair in the clinic.

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.

Brachial Gunshot Wounds: Injury Patterns and Considerations for Managing the Abnormal Neurological Examination.

BACKGROUND: Nerve injuries from gunshot wounds (GSWs) to the upper arm can cause significant morbidity and loss of function. However, indications for surgical exploration and nerve reconstruction remain unclear as both low- and high-grade injuries can present with an abnormal neurological examination. METHODS: Adult patients presenting with a history of isolated GSW to the upper arm between 2010 and 2019 at a single urban level 1 trauma center were screened for inclusion in this retrospective study. Patient demographics, neurological examination findings, concurrent injuries, and intraoperative findings were gathered. Bivariate analysis was performed to characterize factors associated with nerve injuries. RESULTS: There were 139 adult patients with isolated brachial GSWs, and 49 patients (35%) presented with an abnormal neurological examination and significantly associated with concurrent humerus fractures (39% vs 21%, P = .026) and brachial artery injuries (31% vs 2%, P < .001). Thirty of these 49 patients were operatively explored. Fifteen patients were found to have observed nerve injuries during operative exploration including 8 patients with nerve transections. The radial nerve was the most commonly transected nerve (6), and among the 16 contused nerves, the median (8) was most common. CONCLUSION: Nerve injury from upper arm GSWs is common with directly traumatized nerves confirmed in at least 39% and nerve transection in at least 16% of patients with an abnormal neurological examination. Timely referral to a hand and/or peripheral nerve surgeon for close clinical follow-up, appropriate diagnosis, and any necessary surgical reconstruction with nerve grafts, tendon transfers, and nerve transfers is recommended.

The Medial Antebrachial Cutaneous Nerve Is a Low-Morbidity Alternative to the Standard Sural Nerve Autograft.

BACKGROUND: Nerve interposition grafting is an important technique in nerve reconstructive surgery that is used when a primary repair is not feasible without significant tension. This study sought to evaluate the long-term morbidity of the medial antebrachial cutaneous (MABC) nerve as an alternative donor nerve in comparison with sural nerve harvest. METHODS: A single surgeon and institution retrospective chart review was performed to identify all patients who underwent nerve autografting using the sural and MABC as donor nerves between January 1, 2000 and December 31, 2019. Surveys assessed overall patient satisfaction with surgery, as well as donor and recipient site morbidity, satisfaction, pain, numbness, and cold sensitivity. RESULTS: Of the 73 patients contacted, 54 agreed to participate, and 43 of 73 (58.9%) ultimately completed the survey: 28 MABC (65.1%) and 15 sural (34.9%). There were no significant differences between the sural and MABC groups in overall satisfaction with surgery, donor and recipient site satisfaction, pain, cold sensitivity, and effect on quality of life. Even though 66.7% of sural donor sites and 75% of MABC donor sites had residual numbness, the effect this had on quality of life was very low (2 and 3, respectively). CONCLUSION: The MABC is a safe alternative to the traditional sural nerve autograft. A small subset of patients undergoing nerve autograft harvest will experience long-term morbidity in the form of pain. Conversely, the more common presence of numbness is not reported as bothersome.

Retrograde peripheral nerve regeneration from sensory to motor pathways in rats: a new experimental concept in nerve repair.

BACKGROUND: The polarity of nerve grafts does not interfere with axon growth. Our goal was to investigate whether axons can regenerate in a retrograde fashion within sensory pathways and then extend into motor pathways, leading to muscle reinnervation. METHODS: Fifty-four rats were randomized into four groups. In Group 1, the ulnar nerve was connected end-to-end to the superficial radial nerve after neurectomy of the radial nerve in the axilla. In Group 2, the ulnar nerve was connected end-to-end to the radial nerve distal to the humerus; the radial nerve then was divided in the axilla. In Group 3, the radial nerve was divided in the axilla, but no nerve reconstruction was performed. In Group 4, the radial nerve was crushed in the axilla. Over 6 months, we behaviorally assessed the recovery of toe spread in the right operated-upon forepaw by lifting the rat by its tail and lowering it onto a flat surface. Six months after surgery, rats underwent reoperation, nerve transfers were tested electrophysiologically, and the posterior interosseous nerve (PIN) was removed for histological evaluation. RESULTS: Rats in the crush group recovered toe spread between 5 and 8 days after surgery. Rats with nerve transfers demonstrated electrophysiological and histological findings of nerve regeneration but no behavioral recovery. CONCLUSIONS: Ulnar nerve axons regrew into the superficial radial nerve and then into the PIN to reinnervate the extensor digitorum communis. We were unable to demonstrate behavioral recovery because rats cannot readapt to cross-nerve transfer.

Delayed nerve reconstruction for brachial plexus injuries: is the risk worth the reward?

OBJECTIVE: Nerve reconstruction after 6 months of denervation time in brachial plexus injuries (BPIs) can be inconsistent. A dilemma exists when the use of critical donor nerves for nerve transfers may lead to unreliable outcomes that would waste the donor nerve. The purpose of this study was to evaluate the long-term outcomes of elbow and shoulder function in patients with BPIs receiving nerve reconstruction in the delayed setting (i.e., 6-12 months after injury). METHODS: Data from patients with delayed BPIs who received a nerve transfer (including proximal and distal nerve transfer/grafting) at a tertiary medical center were retrospectively collected from January 1999 to March 2020. Demographics, extent of injury, mechanism of injury, and reconstructive methods were collected. Patients were categorized into two groups: non-pan-plexus BPI (C5-6, C5-7, and C5-8) and pan-plexus BPI (C5-T1). Acceptable outcome was defined as elbow flexion ≥ M3 status or shoulder abduction ≥ 60°. RESULTS: Sixty-four patients were included in the study. The average time from injury to nerve reconstruction was 236 (range 180-441) days, and the average follow-up time was 66 months. In the non-pan-plexus BPI group (n = 43 patients), 74.4% of patients demonstrated M3 elbow flexion, and 48.8% of patients demonstrated M4 elbow flexion. Double fascicular transfer yielded better results and faster recovery than a single fascicular transfer. In the pan-plexus BPI group (n = 21 patients), 38.1% of patients reached M3 elbow flexion and 23.8% attained M4 elbow flexion. In the non-pan-plexus BPI group, the recovery rate of acceptable shoulder abduction was 53.5%, but only 23.5% of pan-plexus patients with BPI achieved acceptable shoulder abduction. CONCLUSIONS: Nerve reconstruction can effectively restore functional elbow flexion and acceptable shoulder abduction in non-pan-plexus patients with BPI in the delayed setting. However, neither acceptable elbow flexion nor shoulder abduction could be consistently achieved in pan-plexus BPI. Judicious use of the donor nerves in pan-plexus injuries is required, in addition to preserving a donor nerve for a backup plan such as free-functioning muscle transplantation or tendon transfers.

Quantitative Biofabrication Platform for Collagen-Based Peripheral Nerve Grafts with Structural and Chemical Guidance.

Owing to its crucial role in the human body, collagen has immense potential as a material for the biofabrication of tissues and organs. However, highly refined fabrication using collagen remains difficult, primarily because of its notably soft properties. A quantitative biofabrication platform to construct collagen-based peripheral nerve grafts, incorporating bionic structural and chemical guidance cues, is introduced. A viscoelastic model for collagen, which facilitates simulating material relaxation and fabricating collagen-based neural grafts, achieving a maximum channel density similar to that of the native nerve structure of longitudinal microchannel arrays, is established. For axonal regeneration over considerable distances, a gradient printing control model and quantitative method are developed to realize the high-precision gradient distribution of nerve growth factor required to obtain nerve grafts through one-step bioprinting. Experiments verify that the bioprinted graft effectively guides linear axonal growth in vitro and in vivo. This study should advance biofabrication methods for a variety of human tissue-engineering applications requiring tailored cues.

Clinical anatomy of the lateral antebrachial cutaneous nerve: Is there any safe zone for interventional approach?

INTRODUCTION: The lateral antebrachial cutaneous nerve (LACN) is a somatosensory nerve coursing in the lateral portion of the forearm. The nerve is located in a close proximity to the cephalic vein (CV) all along its course with a danger of being injured during venipuncture. The LACN also overlaps and communicates with the superficial branch of the radial nerve (SBRN) in the distal forearm and hand, making the awareness of their relationship of great importance in the treatment of neuroma. The aim of the study was to observe the relationship of the LACN to surrounding structures as well as its branching pattern and distribution. MATERIALS AND METHODS: Ninety-three cadaveric forearms embalmed in formaldehyde were dissected. The relationship of the LACN to surrounding structures was noted and photographed, and distances between the structures were measured with a digital caliper. The cross-sectional relationships of the LACN and SBRN to the CV were described using heatmaps. RESULTS: The emerging point of the LACN was found distally, proximally or at the level of the interepicondylar line (IEL). The LACN branched in 76 cases (81.7 %) into an anterior and posterior branch at mean distance of 47.8 ± 34.2 mm distal to the IEL. The sensory distribution was described according to the relationship of the LACN branches to the medial border of the brachioradialis muscle. The LACN supplying the dorsum of the hand was observed in 39.8 % of cases. The LACN and the SBRN intersected in 86 % of upper limbs with communications noticed in 71 % of forearms. The LACN was stated as the most frequent donor of the communicating branch resulting in neuroma located distal to the communication and being fed from the LACN. The relationship of the LACN and the CV showed that the IEL is the most appropriate place for the venipuncture due to maximal calibers of the CV and deep position of the LACN. The LACN was adjacent to the cubital perforating vein and the radial artery in all cases. The medial border of the brachioradialis muscle was observed less than 1.8 mm from the LACN. CONCLUSION: The study provides morphological data on the LACN distribution, branching pattern and relationship to surrounding structures in a context of clinical use in different spheres of medicine. The branching pattern of the LACN appears to be more constant compared to data provided by previous authors. We emphasized the meaning of cross-sectional relationship of the LACN to the CV to avoid venipuncture outside the cubital fossa if possible. The posterior branch of the LACN was predicted as appropriate donor of the graft for a digital nerve. The LACN appeared to be in a close proximity within the whole length of the brachioradialis muscle what the orthopedic surgeons must be concerned of. The meaning of the donor-nerve of the communicating branch in neuroma treatment was also introduced.

Vascularized Sural Nerve Graft, Fascial Free Flap, and Regenerative Peripheral Nerve Interface in the Setting of Recurrent Thigh Liposarcoma: A Case Report.

Background: There is no clear consensus in the literature regarding clinical indications for vascularized nerve grafts. Most studies indicate that vascularized nerve grafting, rather than non-vascularized nerve grafting, is indicated for nerve gaps of greater than 7 cm. Vascularized nerve grafts are superior to non-vascularized nerve grafts because they possess an independent blood supply. However, not all nerve injuries can be repaired via vascularized nerve grafts. Methods: A 32-year-old female received a fascial free flap and vascularized sural nerve graft after having multiple reresections of a recurrent thigh liposarcoma. Results: A 25-cm segment of the sural nerve was isolated alongside the lesser saphenous vein and intervening fascia. The free fascial flap was subsequently reversed and placed into the thigh. Vascular anastomoses were created, and the sural nerve was anastomosed to the peroneal nerve. A small portion of muscle from the thigh was wrapped around tibial nerve fascicles of the sciatic nerve to create a regenerative nerve interface. Conclusions: Benefits of vascularized sural nerve graft compared with other vascularized nerve grafts include negligible sensory loss at the donor site and a nerve graft that can be designed on itself due to its vast length. Additionally, vascularized sural nerve grafts provided a better rate of axonal regeneration, rate of electromyographic return, and motor and sensory outcome compared with non-vascularized sural nerve grafts.

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.

Plexiform Schwannoma of Digital Nerve.

Plexiform schwannoma is an uncommon benign tumour that grows in a plexiform pattern. We report a 47-year-old man with a mass on the palmar aspect of the metacarpophalangeal joint of the right index finger that had been growing gradually for more than 10 years. The mass was palpated from the distal carpal tunnel to the ulnar aspect of the proximal interphalangeal joint of the index finger, with tingling and numbness sensation. The tumour was a multinodular tumour involving the first common palmar digital nerve to the ulnar proper palmar digital nerve. It was resected and reconstructed with a sural nerve graft. Plexiform schwannoma is rare in the digital nerve, with only six cases reported. Generally, classic schwannomas can be enucleated without causing neurologic deficits; however, plexiform schwannoma may require nerve resection. There have been reports of recurrence of plexiform schwannoma; definitive resection and long-term follow-up are necessary. Level of Evidence: Level V (Therapeutic).

Correlation between histopathological nerve assessment and clinical recovery in brachial plexus birth injuries.

In the management of brachial plexus birth palsies, the quality of the roots eligible for reconstruction is thought to be a key issue. The aim of the present study was to evaluate the correlations between pathological root examination and motor recovery after brachial plexus reconstructions. Quantitative histopathological analysis of intraneural fibrosis was conducted on 72 nerve transections (40 roots, 18 trunks and 14 suprascapular nerves) in 20 patients. Clinical recovery of targeted muscles after surgery was assessed by standardized functional scores. After a mean follow-up of 32 months, patients with a lower fibrosis rate for the suprascapular nerve had greater global Mallet scores (r = -0.57; p = 0.042) as well as a greater active shoulder flexion (r = -0.66; p = 0.015). Correlations were also found between C6 root and upper trunk fibrosis rate and some of the subsections of the Mallet score, active movement scale for the biceps and active elbow flexion. These results seem to confirm the relevance of intraoperative pathological evaluation of the roots and nerves after neuroma resection to optimally define the reconstruction strategy.Level of evidence: IV.

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.

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.

Fucoidan and microtopography on polyvinyl alcohol hydrogels guided axons and enhanced neuritogenesis of pheochromocytoma 12 (PC12) cells.

Artificial nerve grafts that support axon growth hold promises in promoting nerve regeneration and function recovery. However, current artificial nerve grafts are insufficient to regenerate axons across long nerve gaps. Specific biochemical and biophysical cues are required to be incorporated to artificial nerve grafts to promote neural cell adhesion and guide neurite outgrowth. Polyvinyl alcohol (PVA) nerve conduits have been clinically approved, but the applicability of PVA nerve conduits is limited to short injuries due to low cell binding. In this study, we explored the incorporation of biochemical cues and topographical cues for promoting neuritogenesis and axon guidance. PVA was conjugated with extracellular matrix proteins and fucoidan, a bioactive sulfated polysaccharide, to improve cell adhesion. Micro-sized topographies, including 1.8 µm convex lenses, 2 µm gratings, and 10 µm gratings were successfully fabricated on PVA by nanofabrication, and the synergistic effects of topography and biochemical molecules on pheochromocytoma 12 (PC12) neuritogenesis and neurite alignment were studied. Conjugated fucoidan promoted the percentage of PC12 with neurite outgrowth from 0% to 2.8% and further increased to 5% by presenting laminin on the surface. Additionally, fucoidan was able to bind nerve growth factor (NGF) on the surface and allow for PC12 to extend neurites in NGF-free media. The incorporation of 2 µm gratings could double the percentage of PC12 with neurite outgrowth and neurite length, and guided the neurites to extend along the grating axis. The work presents a promising strategy to enhance neurite formation and axon guidance, presenting significant value in promoting nerve regeneration.

Neural tissue-engineered prevascularization in vivo enhances peripheral neuroregeneration via rapid vascular inosculation.

Neural tissue engineering techniques typically face a significant challenge, simulating complex natural vascular systems that hinder the clinical application of tissue-engineered nerve grafts (TENGs). Here, we report a subcutaneously pre-vascularized TENG consisting of a vascular endothelial growth factor-induced host vascular network, chitosan nerve conduit, and inserted silk fibroin fibers. Contrast agent perfusion, tissue clearing, microCT scan, and blood vessel 3D reconstruction were carried out continuously to prove whether the regenerated blood vessels were functional. Moreover, histological and electrophysiological evaluations were also applied to investigate the efficacy of repairing peripheral nerve defects with pre-vascularized TENG. Rapid vascular inosculation of TENG pre-vascularized blood vessels with the host vascular system was observed at 4 â€‹d bridging the 10 â€‹mm sciatic nerve defect in rats. Transplantation of pre-vascularized TENG in vivo suppressed proliferation of vascular endothelial cells (VECs) while promoting their migration within 14 â€‹d post bridging surgery. More importantly, the early vascularization of TENG drives axonal regrowth by facilitating bidirectional migration of Schwann cells (SCs) and the bands of Büngner formation. This pre-vascularized TENG increased remyelination, promoted recovery of electrophysiological function, and prevented atrophy of the target muscles when observed 12 weeks post neural transplantation. The neural tissue-engineered pre-vascularization technique provides a potential approach to discover an individualized TENG and explore the innovative neural regenerative process.

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.

Chimerization of Monitor Flap in a Vascularized Ulnar Nerve Flap Is an Efficient Way for Vascularity Monitoring and the Reinnervation Checkup after Its Transplantation.

Background Free vascularized ulnar nerve flaps (VUNF) are effective method for long nerve defects reconstruction. However, the monitorization of its microvascular circulation and the nerve regrowth can be challenging since it is usually designed as a buried flap. We designed a skin paddle based on a septocutaneous perforator from the ulnar artery that can be dissected and raised in conjunction with the vascularized ulnar nerve flap, which aims to improve postoperative monitorization to optimizing the clinical results. Methods We retrospectively reviewed 10 cases with long nerve defects who underwent reconstruction using VUNF between June 2018 and June 2019, including eight acute brachial plexus injuries, 1 multiple nerve injury due to a rolling machine accident, and 1 sequalae of nerve injury after arm replantation. All the demographic data, surgical details, outcomes, and perioperative complications were recorded. Results We evaluated 10 male patients, with a mean age of 34 ± 16 years. Cases included 5 antegrade, 4 retrograde, and 1 U-shaped VUNF. All chimeric skin paddles survived, and all of the underlying nerves presented with adequate circulation and functional improvement. There were no intraoperative or microvascular complications. One skin paddle had a transitory postoperative circulation compromise due to external compression (bandage) which resolved spontaneously after pressure release. Conclusion VUNF chimerization of a septocutaneous perforator skin flap is a relatively easy and efficient method for postoperative monitorization of the nerve's microvascular circulation as well as beneficial for postoperative Tinel's sign checkup to confirm the success of the nerve coaptation. The outcome is potentially improved.

Artificial intelligence-based numerical analysis of the quality of facial reanimation: A comparative retrospective cohort study between one-stage dual innervation and single innervation.

This study aimed to investigate the difference in facial reanimation surgery using functional gracilis muscle transfer between the masseteric nerve alone and its combined use with cross face nerve graft (CFNG), which has not been explored before. A novel analysis method based on artificial intelligence (AI) was employed to compare the outcomes of the two approaches. Using AI, 3-dimensional facial landmarks were extracted from 2-dimensional photographs, and distance and angular symmetry scores were calculated. The patients were divided into two groups, with Group 1 undergoing one-stage CFNG and masseteric nerve dual innervation, and Group 2 receiving only masseteric nerve. The symmetry scores were obtained before and 1 year after surgery to assess the degree of change. Of the 35 patients, Group 1 included 13 patients, and Group 2 included 22 patients. The analysis revealed that, in the resting state, the change in the symmetry score of the mouth corner showed distance symmetry (2.55 ± 2.94, 0.52 ± 2.75 for Group 1 and Group 2, respectively, p = 0.048) and angle symmetry (1.21 ± 1.43, 0.02 ± 0.22 for Group 1 and Group 2, respectively, p = 0.001), which were significantly improved in Group 1, indicating a more symmetric pattern after surgery. In the smile state, only the angle symmetry was improved more symmetrically in Group 1 (3.20 ± 2.38, 1.49 ± 2.22 for Group 1 and Group 2, respectively, p = 0.041). Within the limitations of the study it seems that this new analysis method enabled a more accurate numerical symmetry score to be obtained, and while the degree of mouth corner excursion was sufficient with only the masseteric nerve, accompanying CFNG led to further improvement in symmetry in the resting state.