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.

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.

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).

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.

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.

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.

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.

Differences in the surgical treatment of adult and pediatric brachial plexus injuries among peripheral nerve surgeons

OBJECTIVES

Peripheral nerve surgeons disagree on the optimal timing and treatment of brachial plexus injuries (BPI). This study aims to survey peripheral nerve surgeons on their management of BPI, including disagreement.

METHODS

Surgeons responded to a case-based survey involving traumatic and birth injuries leading to BPI involving the upper and lower trunks, and pre- and post-ganglionic injuries.

RESULTS

Out of 255 invited surgeons, 154 participated, with specialties of Neurosurgery (33.7%), Plastic surgery (32.5%), and Orthopedics (32.5%). For the adult C5-6 avulsion injury, 97.4% agreed they would operate. There was 46.2% disagreement regarding the pediatric upper trunk neuroma-in-continuity case, and similar disagreement (50.0%) was recorded on exploring the brachial plexus for a pediatric lower trunk injury case. High percentages of surgeons were more likely to explore the plexus, such as at upper BPI. Also, most participants reported nerve transfer for the upper and lower trunk avulsion injuries, but there was 55.6% disagreement regarding nerve transfer for the infant with the upper trunk neuroma-in-continuity. Among those elected to perform nerve transfer, most (70.0%-84.5%) would perform an accessory-to-suprascapular nerve transfer for upper BPI, while brachialis-to-anterior interosseous and supinator branch of the radial nerve-to-posterior interosseous were preferred for lower BPI (30.0%-55.9%).

CONCLUSIONS

Substantial disagreement exists among peripheral nerve surgeons in managing adult and pediatric BPI. In adult BPI, most prefer to operate at the time of the presentation and perform extensive nerve transfers. The accessory-suprascapular transfer was recommended for upper BPI, while brachialis and radial nerves were preferred for lower BPI. The most significant disagreements exist in operation and nerve transfer for pediatric upper BPI and brachial plexus explorations. Geography, specialty, and operative volume contribute to the differences seen.

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.

Rare malignant peripheral nerve sheath tumor of vagus nerve: A case report

INTRODUCTION

MPNST is a rare type of malignancy classified as malignant soft tissue sarcoma. One-fourth to one-half of MPNST arise in patients with neurofibromatosis type 1 (NF1) and generally involves major nerve trunks of proximal extremities and body, rarely head and neck region. Aggressive nature of the disease shows poor overall prognosis, where treatment modalities are also limited.

PRESENTATION OF CASE

62-year-old otherwise healthy female underwent radical surgical treatment due to the mass of the right side of the neck. Preoperative MRI studies showed well defined partly cystic and visually malignant neoplasm of the carotid sheath in upper third of the neck. Well-defined tumor of the right vagus nerve was detected during the surgery and was excised with safe and radical margins. Further histological study confirmed MPNST diagnosis. Defect of the vagus nerve was reconstructed with a nerve grafts to maintain and improve patients quality of the life. Adjuvant radiotherapy was appointed. At one year follow-up period no evidence of disease recurrence was found. Nevertheless, patient reported significant improvement of functionality and less vagus nerve impairment symptoms.

DISCUSSION

In this article we discuss main epidemiological data of MPNST as well as distinction of our clinical case peculiarities from data mentioned in literature.

CONCLUSION

MPNST are described as aggressive neoplasms with unfavorable short and long-term prognosis. Early diagnosis and radical surgical intervention not only improve patient prognosis but also allow to use additional treatment options to improve patients survival and quality of the life even in case of MPNST.

'Are dynamic procedures superior to static in treating the paralytic eyelid in facial paralysis?'

BACKGROUND

Facial nerve weakness can cause deficient eye closure with reduced corneal protection. Surgical remedies can be static to oppose the levator muscle (lid loading) or dynamic procedures, which act to increase the strength of closure. This retrospective cohort study compares these groups. The hypothesis is that dynamic reconstruction has advantages over static techniques in terms of eye closure, symptomatic improvement, blink restoration, and complication rate.

METHODS

Two cohorts were compared: those treated with a gold weight insertion into the upper eyelid and those who had received dynamic reconstruction. These included temporalis transfer; cross face nerve grafting alone (CFNG) and CFNG followed by free tissue transfer. Assessments included standard photography and video; measurement of eyelid excursion including residual gap and if full eye closure was possible. The presence of the blink reflex and symptoms of dry eye was assessed.

RESULTS

Overall improvement in eye closure was similar with the gold weight compared to dynamic procedures (5.1 mm vs 5.3 mm). Dynamic procedures however gave improved results in terms of symptom relief and restoration of blink. They also had fewer complications and revision rates overall.

CONCLUSION

The study confirms the hypothesis that dynamic reconstructions of the paralysed eyelid confer advantages compared to simple lid loading techniques. Improvements in lid excursion are similar, but symptom improvement and blink restoration are significantly better. A decision regarding eyelid reanimation should be made early in the patient's journey of facial reanimation to allow for accurate planning and placement of nerve grafts at an early stage.

Peripheral nerve regeneration in rats using nerve graft in a vein conduit pre-filled with platelet-rich fibrin (PRF)

Treatment of peripheral nerve injury is not always satisfactory. To improve results, specific adjuvant methods have been used, such as platelet-rich fibrin (PRF) and vein conduits. The goal of this study was to assess whether use of PRF and vein conduits after nerve suture improves nerve regeneration as measured by a functional score and histomorphometry analysis. Ten isogenic spontaneously hypertensive rats were randomly assigned to 4 experimental procedures: 1) Sham group (n = 10); 2) Nerve graft (NG) group (n = 10); 3) Nerve graft covered with a vein conduit (NGVC) (n = 10); and 4) Nerve graft covered with a vein conduit pre-filled with PRF (NGVCP) (n = 10). Nerve repair results were evaluated on: sciatic functional index (SFI) at 0, 30, 60 and 90 days; morphometric and morphologic analysis of the distal nerve; and histological analysis of Fluoro-Gold® stained motor neurons in the anterior horn of the spinal cord. Compared to the Sham control group, the NGVC and NGVCP groups exhibited lower SFI on all measures. The NGVC group showed improvement in SFI at day 90, which was significant compared to the NG group. Fiber and axon diameters were comparable in the NGVC and NGVCP groups, which were both significantly lower than in the Sham and NG groups. Significant improvement was expected with PRF, but in fact the release of factors from this substance was not as effective as hoped.

Surgical Treatment of Foot Drop: Patient Evaluation and Peripheral Nerve Treatment Options

Foot drop is a common clinical condition which may substantially impact physical function and health-related quality of life. The etiologies of foot drop are diverse and a detailed history and physical examination are essential in understanding the underlying pathophysiology and capacity for spontaneous recovery. Patients presenting with acute foot drop or those without significant spontaneous recovery of motor deficits may be candidates for surgical intervention. The timing, mechanism, and severity of neural injury resulting in foot drop influence the selection of the most appropriate peripheral nerve surgery, which may include direct nerve repair, neurolysis, nerve grafting, or nerve transfer.

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.

Peripheral nerve regeneration: A comparative study of the effects of autologous bone marrow-derived mesenchymal stem cells, platelet-rich plasma, and lateral saphenous vein graft as a conduit in a dog model

BACKGROUND

The quality of healing of peripheral nerve injuries remains a common challenge causing pain and poor quality of life for millions of people and animals annually.

AIMS

The objectives of this study were to evaluate the healing quality of facial nerve injury in a dog model following local treatment using an autologous injection of platelet-rich plasma (PRP) or bone marrow-derived mesenchymal stem cells (BM-MSCs) at the injury site in combination with the application of an autologous saphenous vein graft as a conduit.

METHODS

20 apparently healthy adult Mongrel dogs were randomly divided into 4 equal groups. Dogs in groups 1, 2, and 3 were subjected to facial nerve neurectomy and saphenous vein conduit graft implantation at the site of facial nerve injury. Dogs in groups 2 and 3 received 1 ml of autologous PRP and BM-MSCs, respectively. Injections were administered directly in the vein conduit immediately after nerve injury. Dogs in group 1 (grafted but not treated; control) received only an autologous vein graft, and those in group 4 (normal control) received no graft and no PRP or BM-MSCs treatment. The dogs were monitored daily for 8 weeks after surgery. Clinical evaluation of the facial nerve, including lower eyelid, ear drooping, upper lip, and tongue functions, was carried out once per week using a numerical scoring system of 0-3. At the end of the study period (week 8), the facial nerve injury site was evaluated grossly for the presence of adhesions using a numerical scoring system of 0-3. The facial nerve injury site was histopathologically assessed for the existence of perivascular mononuclear cell infiltration, fibrous tissue deposition, and axonal injury using H&E-stained tissue sections.

RESULTS

Clinically, BM-MSCs treated dogs experienced significant (p < 0.05) improvement in the lower eyelid, ear, lip, and tongue functions 4 weeks postoperatively compared to other groups. Grossly, the facial nerve graft site in the BM-MSCs treated group showed significantly (p < 0.05) lesser adhesion scores than the other groups. Histopathologically, there was significantly (p < 0.05) less perivascular mononuclear cell infiltration, less collagen deposition, and more normal axons at the facial nerve injury site in the BM-MSCs treated group compared to the other groups.

CONCLUSION

This study showed clinically significant enhancement of nerve regeneration by applying autologous BM-MSCs and autologous vein grafting at the site of facial nerve injury. However, further clinical trials are warranted before this application can be recommended to treat traumatic nerve injuries in the field.

Comparison of nerve conduits and nerve graft in digital nerve regeneration: A systematic review and meta-analysis

The goal of this systematic review and meta-analysis was to compare nerve conduits and nerve graft for peripheral nerve regeneration. This type of lesion frequently causes disability due to pain, paresthesia and motor deficit. On the PICO process, "P" corresponded to patients with peripheral digital nerve lesions of any age, gender or ethnicity, "I" to interventions with nerve conduits or nerve graft, "C" to the control group with no treatment, placebo or receiving other treatment, and "O" to outcome assessment of nerve regeneration. Initial search found in 3859 studies, including 2001 duplicates. The remaining 1858 studies were selected by title and/or abstract; 1798 articles were excluded, leaving 60 articles for full-text review. Thirty-nine of these 60 reports were excluded as not meeting our inclusion criteria, and 21 articles were ultimately included in the systematic review. For patients older than 40 years, there was a greater mean improvement on S2PD and M2PD tests with grafting, which seemed to be the better surgical technique, positively impacting prognosis. On the M2PD test, there was significantly greater improvement in 11-17.99 mm defects with grafting (P < 0.001); this finding should guide surgical strategy in peripheral nerve regeneration, to ensure better outcomes.

Palsy of elbow extension

Elbow extension palsy is generally well tolerated, because when standing up, it is alleviated by gravity. In the case of trunk paralysis or brachial plexus palsy, standing is possible, thus the restoration of active elbow extension improves the hand's positioning above the shoulder, and allows the elbow to be locked in extension, which is necessary during certain activities such as cycling. In these palsy cases, the triceps brachii will be reinnervated by nerve transfers if surgery is performed early enough before irreversible atrophy of the effector muscle sets in. In these situations, secondary tendon transfers are rarely indicated. Few available muscles can be harvested without deleterious consequences on the donor site. Finally, in patients with a very deficient upper limb but with a healthy contralateral limb, when nerve transfers are no longer possible, elbow extension will not be restored. In the tetraplegics using a wheelchair, elbow extension becomes essential for positioning the hand in space and for potentiating the transferable muscles to activate the hand. As nerve transfers have rare indications and are currently being validated in this population, palliative tendon transfers are the reference technique. They must be integrated into an overall upper limb reconstructive surgery program that takes into consideration the potentially usable muscles and the presence of elbow flexion contracture and supination deformity of the forearm. Elbow extension restoration techniques are based on the transfer of two muscles, the posterior deltoid and the biceps brachii. The first is very effective and has very specific requirements, notably good anterior stabilization of the shoulder by the pectoralis major, while the second has broader indications, notably in the case of elbow contracture and inability to stabilize the shoulder anteriorly.

Effectiveness and Biocompatibility of Decellularized Nerve Graft Using an In Vivo Rat Sciatic Nerve Model

BACKGROUND

Decellularized nerve allografting is one of promising treatment options for nerve defect. As an effort to develop more efficient nerve graft, recently we have developed a new decellularization method for nerve allograft. The aim of this study was to evaluate the effectiveness and biocompatibility of nerve graft decellularized by our newly developed method.

METHODS

Forty-eight inbred male Lewis rats were divided into two groups, Group I (autograft group, n = 25), Group II (decellularized isograft group, n = 23). Decellularized nerve grafts were prepared with our newly developed methods using amphoteric detergent and nuclease treatment. Serum cytokine level measurements at 0, 2, and 4 weeks and histologic evaluation for inflammatory cell infiltration at 6 and 16 weeks after nerve graft.

RESULTS

There was no significant difference in mean maximum isometric tetanic force and weight of tibialis anterior muscle or ankle angle at toe-off phase between two groups at 6 and 16 weeks survival time points (p > 0.05). There was no inflammatory cell infiltration in either group and histomorphometric assessments of 6- and 16-week specimens of the isograft group did not differ from those in the autograft group with regard to number of fascicle, cross sectional area, fascicle area ratio, and number of regenerated nerve cells.

CONCLUSION

Based on inflammatory reaction, axonal regeneration, and functional outcomes, our newly developed decellularized nerve grafts were fairly biocompatible and had comparable effectiveness to autografts for nerve regeneration, which suggested it would be suitable for nerve reconstruction as an alternative to autograft.

Management of Traumatic Trigeminal and Facial Nerve Injuries

In the area of craniomaxillofacial trauma, neurosensory disturbances are encountered commonly, especially with regard to the trigeminal and facial nerve systems. This article reviews the specific microanatomy of both cranial nerves V and VII, and evaluates contemporary neurosensory testing, current imaging modalities, and available nerve injury classification systems. In addition, the article proposes treatment paradigms for management of trigeminal and facial nerve injuries, specifically with regard to the craniomaxillofacial trauma setting.

Donor site morbidity after sural nerve grafting: A systematic review

BACKGROUND

Understanding the morbidity of sural nerve harvest is important when counselling patients regarding nerve grafts. Existing data consist of small studies with varying degrees of follow-up and a wide range of reported donor site outcomes. The objective of this study was to systematically review the literature and pool the current data for postoperative outcomes after sural nerve graft harvest.

METHODS

A systematic review of literature was conducted to identify studies that examined donor site outcomes of sural nerve graft harvests.

RESULTS

Five-hundred and fourteen studies were identified through a literature search, and nine studies met inclusion criteria. There were 240 patients who underwent sural nerve grafts. The most common methods for sensory evaluation were patient survey (44.4%) and Semmes-Weinstein evaluation (33.3%). Five studies reported surface areas of sensory loss, and this generally decreased over time after sural nerve grafting. Overall, 87.2% of patients (n = 190) reported sensory loss, 25.6% (n = 42) of patients reported pain, 22.2% (n = 28) of patients reported cold sensitivity, and 10% (n = 20) of patients reported functional impairment at follow-up. When the proximal sural nerve was spared during harvest, the extent of sensory loss and pain were less than harvest at the popliteal fossa (87.4% vs 95.7%, p = 0.0407 and 9.1% vs 35.5%, p = 0.0004, respectively).

CONCLUSIONS

In this study, we present the extent of sensory loss and rates of pain, cold sensitivity, and functional impairment after sural nerve harvest. These data should be discussed prior to surgery in order for patients and surgeons to make an informed decision.

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.

Combining an end to side nerve to masseter transfer with cross face nerve graft for functional upgrade in partial facial paralysis-an observational cohort study

BACKGROUND

Results of a single stage technique combining cross facial nerve graft(s) (CFNG) with an ipsilateral end to side nerve to masseter transfer (NTM) in incomplete facial paralysis are assessed in a retrospective cohort study. The hypothesis is that the technique can safely improve the quality of smile in these patients. End to side coaptations for the recipient facial nerve minimise the risk of iatrogenic function loss, contrasting with the end to end neurorrhaphies used in conventional babysitting procedures.

METHODS

A series of 27 patients was studied through case note review and standardised assessments. Surgical technique involves extensive exposure of the facial nerve and the NTM on the affected side and access is by bilateral preauricular incisions. End to end coaptations are made to the facial nerve on the donor side and on the recipient a standard CFNG is combined with an end to side NTM coaptation. Follow up was a minimum of 9 months from surgery.

RESULTS

Overall improvement in the Sunnybrook scale averaged 33, from a pre-operative score of 40 (p < 0.05). Average upgrade of 4.7 mm of increased movement at the modiolus was achieved (p < 0.05), 43% improvement compared to the normal side. An improved resting symmetry of 3.8 mm was achieved in relevant cases. Where eye closure was strengthened the average improvement was 5 mm of increased lid closure. The smile achieved was spontaneous in 22 of 27 cases.

CONCLUSION

The study confirms the hypothesis that CFNG with NTM transfer offers a physiological upgrade of facial movement in partial facial paralysis, applicable in both early and longstanding cases.

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.

C5/C6 brachial plexus palsy reconstruction using nerve surgery: long-term functional outcomes

INTRODUCTION

In traumatic proximal brachial plexus lesions (i.e., C5/C6), reconstruction of the musculocutaneous, axillary and suprascapular nerves yields satisfactory short- and medium-term functional outcomes.

HYPOTHESIS

Early functional outcomes after nerve surgery will be maintained in the long-term.

METHODS

A retrospective analysis was done using the medical records of 29 patients with C5/C6 palsy treated by nerve surgery. Active range of motion and strength at the elbow (i.e., flexion) and shoulder (i.e., flexion, abduction, external rotation with the elbow at the side of the body and with the arm 90° abducted ) were evaluated clinically using a goniometre and the British Medical Research Council grading scale, respectively.

RESULTS

At a mean follow-up of 46±15 months (25;76), the mean active elbow flexion was 126°±18° (90;150) and the mean strength was 3.8±0.5 (2;4). At the shoulder, mean active flexion, abduction, external rotation with the elbow at the side of the body and with the arm 90° abducted were 109°±39° (0;180), 99°±38° (0;180°), 12°±34° (-80;70) and 3°±21° (-40;50), while mean strength was 3.6±0.8 (0;4), 3.6±0.8 (0;4), 3.4±0.9 (0;4) and 2.5±1.2 (0;4), respectively.

DISCUSSION

In cases of C5/C6 palsy, early nerve surgery yields satisfactory functional outcomes that are maintained over time for elbow flexion and shoulder elevation. However, when the teres minor is not reinnervated, it is difficult to restore satisfactory shoulder external rotation.

LEVEL OF EVIDENCE

IV, Retrospective case study.

Application of bioactive hydrogels combined with dental pulp stem cells for the repair of large gap peripheral nerve injuries

Due to the limitations in autogenous nerve grafting or Schwann cell transplantation, large gap peripheral nerve injuries require a bridging strategy supported by nerve conduit. Cell based therapies provide a novel treatment for peripheral nerve injuries. In this study, we first experimented an optimal scaffold material synthesis protocol, from where we selected the 10% GFD formula (10% GelMA hydrogel, recombinant human basic fibroblast growth factor and dental pulp stem cells (DPSCs)) to fill a cellulose/soy protein isolate composite membrane (CSM) tube to construct a third generation of nerve regeneration conduit, CSM-GFD. Then this CSM-GFD conduit was applied to repair a 15-mm long defect of sciatic nerve in a rat model. After 12 week post implant surgery, at histologic level, we found CSM-GFD conduit could regenerate nerve tissue like neuron and Schwann like nerve cells and myelinated nerve fibers. At physical level, CSM-GFD achieved functional recovery assessed by a sciatic functional index study. In both levels, CSM-GFD performed like what gold standard, the nerve autograft, could do. Further, we unveiled that almost all newly formed nerve tissue at defect site was originated from the direct differentiation of exogeneous DPSCs in CSM-GFD. In conclusion, we claimed that this third-generation nerve regeneration conduit, CSM-GFD, could be a promising tissue engineering approach to replace the conventional nerve autograft to treat the large gap defect in peripheral nerve injuries.

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A novel 3^rd generation nerve conduit was successfully constructed and applied for repairing peripheral nerve injuries (PNI).

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Dental pulp stem cells (DPSCs) was optimized as an ideal seeding cells for nerve regeneration.

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A bioactive system combining GelMA with human bFGF and DPSCs could reconstruct the long gap PNI within 12 weeks in vivo.

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Our system could achieve the same outcome in nerve repair as that of autografting, a routine treatment for PNI.

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The proposed bioactive system may trigger an evolutional change into the current clinical practice in managing PNI.

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The majority of the regenerated nerve tissue was originated from the donor’s dental pulp stem cells.

Electrical stimulation to enhance peripheral nerve regeneration: Update in molecular investigations and clinical translation

Peripheral nerve injuries are common and frequently result in incomplete functional recovery even with optimal surgical treatment. Permanent motor and sensory deficits are associated with significant patient morbidity and socioeconomic burden. Despite substantial research efforts to enhance peripheral nerve regeneration, few effective and clinically feasible treatment options have been found. One promising strategy is the use of low frequency electrical stimulation delivered perioperatively to an injured nerve at the time of surgical repair. Possibly through its effect of increasing intraneuronal cyclic AMP, perioperative electrical stimulation accelerates axon outgrowth, remyelination of regenerating axons, and reinnervation of end organs, even with delayed surgical intervention. Building on decades of experimental evidence in animal models, several recent, prospective, randomized clinical trials have affirmed electrical stimulation as a clinically translatable technique to enhance functional recovery in patients with peripheral nerve injuries requiring surgical treatment. This paper provides an updated review of the cellular physiology of electrical stimulation and its effects on axon regeneration, Level I evidence from recent prospective randomized clinical trials of electrical stimulation, and ongoing and future directions of research into electrical stimulation as a clinically feasible adjunct to surgical intervention in the treatment of patients with peripheral nerve injuries.

Reconstruction of a long defect of the median nerve with a free nerve conduit flap

Upper limb nerve damage is a common condition, and evidence suggests that functional recovery may be limited following peripheral nerve repair in cases of delayed reconstruction or reconstruction of long nerve defects. A 26-year-old man presented with traumatic injury from a wide, blunt wound of the right forearm caused by broken glass, with soft tissue loss, complete transection of the radial and ulnar arteries, and a large median nerve gap. The patient underwent debridement and subsequent surgery with a microsurgical free radial fasciocutaneous flap to provide a direct blood supply to the hand; the cephalic vein within the flap was employed as a venous vascularized chamber to wrap the sural nerve graft and to repair the wide gap (14 cm) in the median nerve. During the postoperative period, the patient followed an intensive rehabilitation program and was monitored for functional performance over 5 years of follow-up. Our assessment demonstrated skin tropism and sufficient muscle power to act against strong resistance (M5) in the muscles previously affected by paralysis, as well as a good localization of stimuli in the median nerve region and an imperfect recovery of two-point discrimination (S3+). We propose a novel and efficient procedure to repair >10-cm peripheral nerve gap injuries related to upper limb trauma.

A single session of brief electrical stimulation enhances axon regeneration through nerve autografts

Nerve graft reconstruction of gap defects may result in poor clinical outcomes, particularly with long regeneration distances. Electrical stimulation (ES) of nerves may improve outcomes in such patients. A single session of ES at 20 Hz for 1 h significantly enhances axon regeneration in animals and human subjects after nerve crush or nerve transection and repair. The objectives of this study were to evaluate if ES enhances axon regeneration through nerve grafts and if there is added benefit of a second, delayed session of ES (serial ES) on axon regeneration as compared to a single session only of ES. In female rats, a gap defect was created in the hindlimb common peroneal (CP) nerve and immediately reconstructed with a 10 mm nerve autograft (Experiment 1) or a 20 mm nerve autograft (Experiment 2). In Experiment 1, rats were randomized to 1 h of CP nerve ES or sham stimulation. In Experiment 2, rats were randomized to control (sham ES + sham ES), single ES (ES + sham ES), or serial ES (ES + ES), which consisted of an initial 1 h session of either ES or sham stimulation of the CP nerve, followed by a second 1 h session of ES or sham stimulation of the CP nerve 4 weeks later. In both experiments, after a 6 week period of nerve regeneration, CP neurons that had regenerated axons distal to the autograft were retrograde labelled for enumeration, and the CP nerve distal to the autograft was harvested for histomorphometry. In Experiment 1, rats that received CP nerve ES had statistically significantly more motor (p < .05) and sensory (p < .05) neurons that regenerated axons distal to the 10 mm nerve autograft, with more myelinated axons on histomorphometry (p < .001). Similarly, in Experiment 2, significantly more motor (p < .01) and sensory (p < .05) neurons regenerated axons distal to the 20 mm nerve autograft after a single session or two sessions of CP nerve ES. There was no significant difference in the number of regenerated motor or sensory neurons between rats with 20 mm CP nerve autografts receiving either one or two sessions of CP nerve ES (p > .05). In conclusion, a single session of ES enhances axon regeneration following nerve autografting with no added effect of a second, delayed session of ES. These findings support previous studies in animals and humans of the robust effect of a single session of ES in promoting nerve regeneration following injury and repair.

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.

Facial nerve repair: the impact of technical variations on the final outcome

OBJECTIVES

To analyze the outcome of facial nerve (FN) reconstruction, the impact of technical variations in different conditions and locations, and the importance of additional techniques in case of suboptimal results.

STUDY DESIGN

Retrospective study.

SETTING

University-based tertiary referral center.

PATIENTS

Between 2001 and 2017, reconstruction of the FN was performed on 36 patients with varying underlying diseases.

INTERVENTIONS

FN repair was performed by direct coaptation (n = 3) or graft interposition (n = 33). Microsurgical sutures were used in 17 patients (47%) and fibrin glue was used in all cases. Additional reinnervation techniques (hypoglossal-facial or masseter-facial transfers) were performed in five patients with poor results after initial reconstruction.

MAIN OUTCOME MEASURES

FN function was evaluated using the House-Brackmann (HB) and the electronic clinician-graded facial function (eFACE) grading systems. Minimum follow-up was 12 months.

RESULTS

FN reconstruction yielded improvement in 83% of patients, 21 patients (58.3%) achieving a HB grade III. The eFACE median composite, static, dynamic and synkinesis scores were 69.1, 78, 53.2, and 88.2 respectively. A tendency towards better outcome with the use of sutures was found, the difference not being significant. All patients undergoing an additional reinnervation procedure achieved a HB grade III, eFACE score being 74.8.

CONCLUSIONS

FN reconstruction offers acceptable functional results in most cases. No significant differences are expected with technical variations, different locations or conditions. In patients with poor initial results, additional reinnervation techniques should be always considered. The eFACE adds substantial information to the most used HB scale.

Elbow flexion in neonatal brachial plexus palsy: a meta-analysis of graft versus transfer

BACKGROUND

Functional elbow flexion recovery is one of the main goals of neonatal brachial plexus palsy (NBPP) reconstruction. The current neurosurgical treatment options include nerve grafting and nerve transfer.

OBJECTIVE

The present study sought to examine the literature for comparison of functional elbow flexion recovery in NBPP following nerve grafting or nerve transfer. We conducted a systematic literature review and meta-analysis according to PRISMA guidelines. A search was conducted on Pubmed/Medline and Cochrane for eligible studies published until November of 2018. Odd ratios (OR) and 95% confidence intervals (CI) were calculated to compare functional elbow flexion outcomes between nerve graft and nerve transfer. A random effects model meta-analysis was conducted. A Medical Research Council (MRC) score ≥ 3 or Active Movement Scale (AMS) ≥ 5 was considered a functional recovery of elbow flexion.

RESULTS

The present study included 194 patients from 1990 to 2015 across five observational trials. Only pediatric patients with obstetric brachial plexus injury were included. The mean patient age at surgery varied between studies from 5.7 months to 11.9 months and mean follow-up from 12 to 70 months. No complications or cases of donor site morbidity were reported. From the included studies, 118 patients were reported with MRC or AMS scoring usable for odd ratio comparison. Functional recovery occurred with nerve transfer in 95.2% of patients (n = 59/62) and with nerve grafting in 96.4% of patients (n = 54/56). Overall, the outcomes for elbow flexion between the groups appeared similar (OR 1.15, 95% CI 0.19-7.08, I² 2.9%).

CONCLUSION

Comparing nerve grafting and nerve transfer for NBPP, there is no statistically significant difference in functional elbow flexion recovery.

Rat sciatic nerve regeneration across a 10-mm defect bridged by a chitin/CM-chitosan artificial nerve graft

Chitosan as a natural bioactive biopolymer has been commonly employed in guidance conduit for repairing peripheral nerve injury, due to its excellent properties of low toxicity, antibacterial properties, high biocompatibility and biodegradability. In this study, chitin and CM-chitosan were prepared from pharmaceutical grade chitosan. Moreover, a novel composite chitosan-based nerve graft comprising microporous chitin-based conduit and internal CM-chitosan fiber was constructed and applied to bridge sciatic nerve across a 10-mm defect in SD rats. The chitin/CM-chitosan artificial nerve graft could promote the proliferation of rat Schwann cells (RSC96) with good cell biocompatibility. After implantation, the artificial nerve graft showed slow degradation. No apparent toxicity was observed, and tissue inflammation was very slight after implantation, indicating favorable bio-safety of the nerve graft. Furthermore, the chitin/CM-chitosan artificial nerve graft could effectively promote restoration of damaged neurons with similar effect compared to the autograft. In conclusion, the composite biodegradable chitin/CM-chitosan nerve grafts possessed favorable biocompatibility and good potential in repairing peripheral nervous injury.

The Great Auricular Nerve: Anatomical Study with Application to Nerve Grafting Procedures

BACKGROUND

When it comes to autogenous nerve grafting, the sural and great auricular nerve (GAN) are the 2 nerves predominately used for trigeminal and facial nerve repair. Arising from the second and third cervical ventral rami, the GAN emerges from the posterior border of the sternocleidomastoid coursing superiorly and anteriorly toward the ear.

METHODS

Eleven sides from 5 Caucasian and 1 Asian cadaveric heads (all fresh-frozen) were used. One man and 5 women were used with an age at death ranging from 57 to 91 years, with a mean of 80.3 years. Measurements were made from the inferior border of the ear to the GAN, the GAN to the external jugular vein, and the inferior border of the mastoid process to the GAN; the proximal, medial, and distal diameters of the GAN and the length of the GAN that was obtained from this exposure were also measured.

RESULTS

The mean distance from the inferior border of the mastoid process to the GAN, inferior border of the ear to the GAN, and GAN to the external jugular vein was 27.71, 31.03, and 13.28 mm, respectively. The mean length of the GAN was 74.86 mm. The mean diameter of its distal, middle, and proximal portions was 1.51, 1.38, and 1.58 mm, respectively.

CONCLUSIONS

The GAN is an excellent option for use in nerve grafting for repair of, for example, facial dysfunction. In this study, we review our measurements, techniques for identification, and dissecting techniques for the GAN. The proximity to the operative area and minimal complications associated with GAN grafting might contribute to improved patient satisfaction and better outcomes regarding functional restoration.

Short- and long-term results of common peroneal nerve injuries treated by neurolysis, direct suture or nerve graft

INTRODUCTION

Damage to the common peroneal nerve is the most frequent nerve injury in lower limb traumas. Our objective was to assess the motor and sensory recovery levels and the functional outcomes after remedial surgery for common peroneal nerve trauma, through either neurolysis, direct suture or nerve graft.

METHODS

This is a transversal, observational study of a monocentric cohort of 20 patients who underwent surgery between January 2004 and June 2016, which included 16 men and 4 women whose median age was 35 ± 11 years. We assessed the level of sensory and motor nerve recovery and the Kitaoka score. Nine patients benefited from neurolysis, 5 had direct sutures, and 6 received a nerve graft.

RESULTS

With 48 months' average follow-up, 7 out of 9 patients underwent neurolysis and 4 out of 5 with direct sutures had good motor recovery (≥ M4), but none for the grafts. Sensory recovery (≥ S3) was satisfactory in 7 out of 9 cases in the neurolysis group, 3 out of 5 in the direct suture group, and 3 out of 6 in the nerve graft group. The average Kitaoka score was 83.7 ± 11.5 for the neurolysis group, 86.8 ± 16 for the direct suture group, and 73 ± 14 for the graft group.

CONCLUSION

Surgical treatment by neurolysis and direct suture yields good results with a motor recovery ratio nearing 80%. When a nerve graft becomes necessary, recovery is poor and resorting to palliative techniques in the shorter run is a strategy which should be evaluated.

Epineural Sleeve Reconstruction Technique for Median Nerve Complete Transection

In microsurgical nerve repair, the epineural sleeve technique can be used to bridge short nerve defects and to cover the coaptation site with the epineurium of the nerve stump. The epineurium serves as a mechanical aid to reduce gap size, and increase repair strength, effectively assisting nerve regeneration. This article presents a 32-year-old patient who experienced complete transection of the median nerve at the distal forearm, which was treated with the epineural sleeve graft reconstruction technique. Nerve regeneration was followed-up for 18 months and evaluated with the Rosén and Lundborg scoring system. The final outcome was excellent; at the last follow-up, the patient experienced complete sensory and motor function of the median nerve. Level of evidence: V.

Seeding nerve sutures with minced nerve-graft (MINE-G): a simple method to improve nerve regeneration in rats

BACKGROUND

The aim of this study was to assess the effect of seeding the distal nerve suture with nerve fragments in rats.

METHODS

On 20 rats, a 15 mm sciatic nerve defect was reconstructed with a nerve autograft. In the Study Group (10 rats), a minced 1 mm nerve segment was seeded around the nerve suture. In the Control Group (10 rats), a nerve graft alone was used. At 4 and 12 weeks, a walking track analysis with open field test (WTA), hystomorphometry (number of myelinated fibers (n), fiber density (FD) and fiber area (FA) and soleus and gastrocnemius muscle weight ratios (MWR) were evaluated. The Student t-test was used for statistical analysis.

RESULTS

At 4 and 12 weeks the Study Group had a significantly higher n and FD (p = .043 and .033). The SMWR was significantly higher in the Study Group at 12 weeks (p = .0207).

CONCLUSIONS

Seeding the distal nerve suture with nerve fragments increases the number of myelinated fibers, the FD and the SMWR. The technique seems promising and deserves further investigation to clarify the mechanisms involved and its functional effects.

The outcome of primary brachial plexus reconstruction in extended Erb's obstetric palsy when only one root is available for intraplexus neurotization

Background

A recent review by the International Federation of Societies for Surgery of the Hand showed no studies comparing the results of nerve grafting to distal nerve transfer for primary reconstruction of the brachial plexus in infants with obstetric brachial plexus palsy (OBBP). The aim of this retrospective study is to compare two surgical reconstructive strategies in primary reconstruction of the brachial plexus in extended Erb’s obstetric palsy with double root avulsion: one with and one without distal nerve transfer for elbow flexion.

Methods

Two groups of infants with extended Erb’s palsy and double root avulsion were included in the study. Group I (n = 29) underwent reconstruction of the brachial plexus without distal nerve transfer. In group II (n = 26), the reconstruction included a distal nerve transfer for elbow flexion.

Results

Both groups had an excellent (over 96%) satisfactory outcome for elbow flexion. Group II has a significantly better outcome (P < 0.05) of shoulder abduction and wrist extension than group I.

Conclusions

The use of a distant nerve transfer for bicep reconstruction in extended Erb’s obstetric palsy with double root avulsion gives a better outcome for shoulder abduction and wrist extension; and this seems to be related to the availability of more cable grafts to reconstruct the posterior division of the upper trunk and the middle trunk.

Level of Evidence: Level III, therapeutic study

The outcome of primary brachial plexus reconstruction in extended Erb's obstetric palsy when two roots are available for intraplexus neurotization

Background

The outcome of primary brachial plexus reconstruction in extended Erb’s obstetric palsy with single root avulsion has not been specifically documented in the literature.

Methods

A series of 46 consecutive cases of extended Erb’s obstetric palsy with single root avulsion was retrospectively reviewed. The upper and middle trunks were reconstructed with nerve grafts from the available two roots. No nerve transfers were used. The percentage of a satisfactory motor recovery was documented.

Results

The postoperative motor recovery was excellent (over 97%) satisfactory outcome for elbow flexion, elbow extension, and digital extension. A satisfactory wrist extension was noted in 84.8% of children. The lowest rates of satisfactory outcomes were for shoulder external rotation (65.2%) and shoulder abduction (56.5%).

Conclusions

In extended Erb’s obstetric palsy with single root avulsion, two ruptured roots are available for intraplexus neurotization of the upper and middle trunks. The surgeon gives a priority to elbow flexion and this is translated in an excellent outcome for elbow flexion. The triceps and digital extensors get a major contribution form the unaffected C8 root, and this is also translated in an excellent outcome for these two functions. Fewer cable grafts are available for reconstruction of the posterior division of upper trunk and the middle trunk, resulting in a lower rate of satisfactory outcomes at the shoulder for wrist extension.

Level of Evidence: Level IV, therapeutic study.

Humerus shaft fracture complicated by radial nerve palsy: Is surgical exploration necessary?

Fractures of the humerus shaft often are complicated by radial nerve palsy. Controversy still exists in the treatment that includes clinical observation and eventually late surgical exploration or early surgical exploration. Algorithms have been proposed to provide recommendations with regard to management of the injuries. However, advantages and disadvantages are associated with each of these algorithms. The aim of this study was to analyze the indications of each treatment options and facilitate the surgeon in choosing the conduct for each lesion, proposing our own algorithm.

Treatment of complete facial palsy in adults: comparative study between direct hemihypoglossal-facial neurorrhaphy, hemihipoglossal-facial neurorrhaphy with grafts, and masseter to facial nerve transfer

BACKGROUND

The hypoglossal (with or without grafts) and masseter nerves are frequently used as axon donors for facial reinnervation when no proximal stump of the facial nerve is available. We report our experience treating facial nerve palsies via hemihypoglossal-to-facial nerve transfers either with (HFG) or without grafts (HFD), comparing these outcomes against those of masseteric-to-facial nerve transfers (MF).

METHOD

A total of 77 patients were analyzed retrospectively, including 51 HFD, 11 HFG, and 15 MF nerve transfer patients. Both the House-Brackmann (HB) scale and our own, newly-designed scale to rate facial reanimation post nerve transfer (quantifying symmetry at rest and when smiling, eye occlusion, and eye and mouth synkinesis when speaking) were used to enumerate the extent of recovery.

RESULTS

With both the HB and our own facial reanimation scale, the HFD and MF procedures yielded better outcome scores than HFG, though only the HGD was statistically superior. HGD produced slightly better scores than MF for everything but eye synkinesis, but these differences were generally not statistically significant. Delaying surgery beyond 2 years since injury was associated with appreciably worse outcomes when measured with our own but not the HB scale. The only predictors of outcome were the surgical technique employed and the duration of time between the initial injury and surgery.

CONCLUSIONS

HFD appears to produce the most satisfactory facial reanimation results, with MF providing lesser but still satisfactory outcomes. Using interposed grafts while performing hemihypoglossal-to-facial nerve transfers should likely be avoided, whenever possible.

Free Functional Muscle Transfers to Restore Upper Extremity Function

Free functional muscle transfer provides an option for functional restoration when nerve reconstruction and tendon transfers are not feasible. To ensure a successful outcome, many factors need to be optimized, including proper patient selection, timing of intervention, donor muscle and motor nerve selection, optimal microneurovascular technique and tension setting, proper postoperative management, and appropriate rehabilitation. Functional outcomes of various applications to the upper extremity and the authors' algorithm for the use of free functional muscle transfer are also included in this article.

Nerve Transfers in Birth Related Brachial Plexus Injuries: Where Do We Stand?

This article reviews the assessment and management of obstetrical brachial plexus palsy. The potential role of distal nerve transfers in the treatment of infants with Erb's palsy is discussed. Current evidence for motor outcomes after traditional reconstruction via interpositional nerve grafting and extraplexal nerve transfers is reviewed and compared with the recent literature on intraplexal distal nerve transfers in obstetrical brachial plexus injury.

Ultrasound evaluation in traumatic peripheral nerve lesions: from diagnosis to surgical planning and follow-up

Surgical treatment of traumatic nerve lesions is a matter of debate, mostly about the timing and technical aspects of the procedure. In deciding about and planning the operation, it is often necessary to repeat the electrophysiological and neuroradiological studies several times. Here we present our experience with ultrasonography taken before and after surgery: this simple and handy tool allowed clear visualization of the preoperative anatomy, thorough preparation and fast carrying out of surgery, and accurate postoperative monitoring of the graft's vitality at follow-up. Though this is a limited series, the importance of ultrasonographic evaluation in traumatic peripheral nerve lesions appears remarkable.

The use of the ALT Flap and Lateral Femoral Cutaneous Nerve for the Reconstruction of Carpal Soft Tissue and Ulnar Nerve Defects: a Case Report

The anterolateral thigh (ALT) flap has become one of the workhorse flaps, with indications including diverse reconstructive problems. The lateral thigh area is also a useful donor site for nerve grafts. The lateral femoral cutaneous (LFC) nerve can be dissected along with the ALT flap for a substantial length, depending on the requirements of the recipient site. The LFC nerve can be used as a vascularized or non-vascularized nerve graft. The technique offers advantages and it can find clinical applications, satisfying the functional and aesthetic reconstructive requirements of a complex defect. We report the case of a patient who presented with traumatic soft tissue defect of the volar aspect of the wrist and ulnar nerve defect as a complication of a fracture of distal radius. An ALT flap was used to reconstruct the soft tissue defect. The ulnar nerve was resected due to necrosis and the gap was repaired with non-vascularized grafts of the anterior branch of the LFC nerve. The soft tissues were resurfaced successfully without complications. Functional recovery was good for the superficial branch of the ulnar nerve, whereas it was variable for the deep branch of the ulnar nerve. The anterolateral thigh area offers significant advantages as donor site in the reconstruction of complex soft tissue defects being a large source of vascularized skin, fat, fascia, muscle and nerve. This availability allows for single donor site dissection, minimizing the operating time and the associated morbidity.

End-to-side "loop" graft for total facial nerve reconstruction: Over 10 years experience

BACKGROUND

Multiple-branch reconstruction is required in order to attain facial reanimation for extensive facial nerve defects. We previously reported that end-to-side nerve grafting, with the use of a single nerve graft for defect reconstruction, was easy to perform. We have also demonstrated the efficacy of end-to-side nerve suture of the recipient nerve to the donor graft nerve, in experimental rat models and clinical cases. The regenerating axons, which extended into the nerve graft, were "distributed" to multiple recipient nerves via end-to-side nerve-suture sites.

METHODS

Thirty-two patients who underwent facial nerve reconstruction (five to 10 branches) had a single sural nerve graft coapted to the proximal stump of the facial nerve in an end-to-end manner, followed by end-to-side nerve suture of the recipient nerve stumps to the side of the nerve graft. In 19 patients who were expected to undergo postoperative radiotherapy and/or chemotherapy, the distal end of the graft was connected to the side of the hypoglossal nerve for "axonal supercharging," to enhance the recovery of the facial muscles.

RESULTS

Initial facial movements were noted at 5-12 months postoperatively, and good recovery (House-Brackmann grade III/IV) was observed during long-term follow-up in most patients.

CONCLUSION

End-to-side nerve suture of the recipient nerve stumps to the nerve graft requires less graft nerve material and less technical mastery to reconstruct multiple branches of the facial nerve. We also described the concept of "axonal supercharging," namely the connection of double-donor neural sources to the graft, and "axonal distribution," namely the reinnervation of multiple recipient nerve stumps connected to the graft in an end-to-side manner. This combination of axonal supercharging and distribution can be a useful option in facial nerve reconstruction.

Alternatives to sural nerve grafts in the upper extremity

BACKGROUND

The sural nerve is the most common nerve graft donor despite requiring a second operative limb and causing numbness of the lateral foot. The purposes of this study were to review our experience using nerve autografts in upper extremity nerve reconstruction and develop recommendations for donor selection.

METHODS

A retrospective case series study was performed of all consecutive patients undergoing nerve grafting procedures for upper extremity nerve injuries over an 11-year period (2001-2012).

RESULTS

Eighty-six patients received 109 nerve grafts over the study period. Mean patient age was 42.9 ± 18.3 years; 57 % were male. There were 51 median (59 %), 26 ulnar (30 %), 14 digital (13 %), 13 radial (16 %), and 3 musculocutaneous (4 %) nerve injuries repaired with 99 nerve autografts (71 from upper extremity, 28 from lower extremity). Multiple upper extremity nerve autograft donors were utilized, including the medial antebrachial cutaneous nerve (MABC), third webspace branch of median, lateral antebrachial cutaneous nerve (LABC), palmar cutaneous, and dorsal cutaneous branch of ulnar nerve. By using an upper-extremity donor, a second operative limb was avoided in 58 patients (67 %), and a second incision was avoided in 26 patients (30 %). The frequency of sural graft use declined from 40 % (n = 17/43) to 11 % (n = 7/64).

CONCLUSIONS

Our algorithm for selecting nerve graft material has evolved with our growing understanding of nerve internal topography and the drive to minimize additional incisions, maximize ease of harvest, and limit donor morbidity. This has led us away from using the sural nerve when possible and allowed us to avoid a second operative limb in two thirds of the cases.

Anatomic and histological study of great auricular nerve and its clinical implication

BACKGROUND

The great auricular nerve (GAN) is often sacrificed during parotidectomy, rhytidectomy, and platysma flap operation. Transection of the nerve results in a wooden numbness of preauricular region, pain, and neuroma. The aim of this study was to describe the branching patterns and distribution area of the GAN.

METHODS

Twenty-five embalmed, adult hemifacial Korean cadavers (16 males, nine females; mean age 62.5 years) were used in this study. The branching of the GAN was determined through careful dissection. The histological structure of the GAN was also examined by harvesting and sectioning specimens, and then viewing them with the aid of a light microscope.

RESULTS

The branching pattern of the anterior, posterior, deep, and superficial branches of the GAN could be classified into five types: type I (20%), where the deep branches arose from the anterior branch; type II (24%), where all branches originated at the same point; type III (28%), where the deep branch arose from the posterior branch; type IV (8%), where the superficial branches arose from the posterior branch; and type V (20%), where the anterior and posterior branches ran independently. A connection between the GAN and the facial nerve trunk was observed in all specimens, and a connection with the auriculotemporal nerve was observed in a few specimens. The total fascicular area of both regions decreased from proximal (1.42 mm2) to distal (0.60 mm2). There were 2.5 and 5 fascicles in the proximal and distal regions, respectively.

CONCLUSION

The results reported herein will help toward preservation of the GAN during surgery in the region of the parotid gland. Furthermore, the histologic findings suggest that the GAN would be a good donor site for nerve grafting.