The effect of increasing motor end-plate innervation on smile activation in acute and early facial palsy.

While it has been over half a century since primary cross-facial nerve grafting was first described for facial reanimation, the outcome of this procedure, remains inconsistent and provide lesser smile excursion when compared to the likes of the masseteric nerve. However, the latter itself has limitations in terms of the lack of spontaneity and resting tone. While combinations have been attempted more proximally, we ask the question as to whether more distal nerve transfers with vascularized nerve grafts are a better option. In a retrospective review of clinical practice at our institute, 16 consecutive patients had single, double, and finally triple distal nerve transfers, close to the target facial muscle to reinnervate the motor endplates directly, over a 6-year period (2018-23). All patients had the onset of facial palsy within 18 months. Statistical analysis of the comparison between three sub-cohorts was performed using student's t-test and one-way ANOVA, respectively. Qualitatively, masseteric neurotization of a single facial nerve branch translated into smile improvement in 50% of cases, as opposed to all cases of double- and triple-neurotization of the smile muscles. In terms of upper lip elevation, single neurotization showed improvement in 25% of cases, double-neurotization in 40% of cases and triple-neurotization in 100% of cases. Upper lip elevation was also significantly better in those who had a vascularized cross-facial nerve graft (Student's t-test <0.05). In summary, increasing neural input to the motor endplates of smile muscles can significantly improve smile activation, in acute flaccid facial palsies.

[Femoral nerve repair with autografts for proximal retroperitoneal damage (case report and literature review)]. / Autoplastika bedrennogo nerva pri ego proksimal'nom zabryushinnom povrezhdenii (klinicheskoe nablyudenie i obzor literatury).

Femoral nerve damage, especially in proximal retroperitoneal space, is rare. Therefore, surgical strategy is still unclear for these patients. Various specialists discuss repair with autografts or neurotization by the obturator nerve or its muscular branch. OBJECTIVE: To demonstrate the diagnostic algorithm for proximal femoral nerve injury and favorable outcomes after repair with long autografts. MATERIAL AND METHODS: We assessed movements and sensitivity using a five-point scale, as well as ultrasound, magnetic resonance imaging and electroneuromyography data in a patient with extended iatrogenic femoral nerve damage before and after repair with long autografts (10.5 cm). RESULTS AND DISCUSSION: The patient had complete femoral nerve interruption in proximal retroperitoneal space with 10-cm defect that required repair with five autografts from two sural nerves. Postoperative ultrasound and magnetic resonance imaging revealed signs of graft survival and no neuroma within the nerve suture lines. The first signs of motor recovery occurred after 10 months. After 14 months, strength of quadriceps femoris muscle comprised 4 points, and electroneuromyography confirmed re-innervation. CONCLUSION: Femoral nerve repair with autografts for complete proximal anatomical interruption can provide sufficient restoration of movements and sensitivity. Therefore, this surgical option should be preferred instead of neurotization. Ultrasound, MRI and ENMG are valuable to clarify the diagnosis and state of the autografts.

The Effectiveness of Different Nerve Transfers in the Restoration of Elbow Flexion in Adults Following Brachial Plexus Injury: A Systematic Review and Meta-Analysis.

PURPOSE: Restoration of elbow flexion is an important goal in the treatment of patients with traumatic brachial plexus injury. Numerous studies have described various nerve transfers for neurotization of the musculocutaneous nerve (or its motor branches); however, there is uncertainty over the effectiveness of each method. The aim of this study was to summarize the published evidence in adults with traumatic brachial plexus injury. METHODS: Medline, Embase, medRxiv, and bioRxiv were systematically searched from inception to April 12, 2021. We included studies that reported the outcomes of nerve transfers for the restoration of elbow flexion in adults. The primary outcome was elbow flexion of grade 4 (M4) or higher on the British Medical Research Council scale. Data were pooled using random-effects meta-analyses, and heterogeneity was explored using metaregression. Confidence intervals (CIs) were generated to the 95% level. RESULTS: We included 64 articles, which described 13 different nerve transfers. There were 1,335 adults, of whom 813 (61%) had partial and 522 (39%) had pan-plexus injuries. Overall, 75% of the patients with partial brachial plexus injuries achieved ≥M4 (CI, 69%-80%), and the choice of donor nerve was associated with clinically meaningful differences in the outcome. Of the patients with pan-plexus injuries, 45% achieved ≥M4 (CI, 31%-60%), and overall, each month delay from the time of injury to reconstruction reduced the probability of achieving ≥M4 by 7% (CI, 1%-12%). CONCLUSIONS: The choice of donor nerve affects the chance of attaining a British Medical Research Council score of ≥4 in upper-trunk reconstruction. For patients with pan-plexus injuries, delay in neurotization may be detrimental to motor outcomes. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

How to Enhance the Success of Selective Neurectomy for Facial Synkinesis by Considering the Patient's Preferences: Lesson Learned from a Retrospective Analysis of 122 Cases.

BACKGROUND: Facial synkinesis can result in facial tightness, smile dysfunction, and eyelid aperture narrowing due to overactive and uncoordinated muscle activity. We hypothesized that the outcome of a selective neurectomy could rely on the patient's chief complaints. METHODS: We retrospectively reviewed 122 patients who underwent selective neurectomy at our hospital. Preoperatively, the patients were asked nine questionnaires to identify their two major chief complaints (treatment priorities). Postoperatively, facial tightness, limited mouth movement, and eyelid aperture narrowing were measured. RESULTS: The most common chief complaints in our series were facial tightness (n=38), eyelid narrowing (n=32), and limited mouth movement (n=28); the second most common chief complaints (second priority) were limited mouth movement (n=47), facial tightness (n=21), and eyelid narrowing (n=20). The mean score for facial tightness significantly improved from 4.3 to 1.1 in the first priority group. Among the 28 patients whose corners of the mouth constituted the top priority of surgical correction, the vertical inclination on the affected side significantly improved from 74.1 ± 7.6° to 55.5 ± 6.0°, and the horizontal angles were changed from 4.2 ± 2.7° to 2.0 ± 1.3° after selective neurectomy without statistically significant. Among the 32 patients for whom eyelid narrowing constituted the top priority, the mean eyelid narrowing score improved from 4.5 ± 1.1 to 1.5 ± 1.2. CONCLUSIONS: Selective neurectomy can provide a significantly satisfactory outcome regarding facial tightness and eyelid aperture narrowing. The vertical inclination of the mouth corner can be significantly improved, while the improvement of horizontal angles can be suboptimal. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

The Role of Sensory Innervation in Homeostatic and Injury-Induced Corneal Epithelial Renewal.

The cornea is the window through which we see the world. Corneal clarity is required for vision, and blindness occurs when the cornea becomes opaque. The cornea is covered by unique transparent epithelial cells that serve as an outermost cellular barrier bordering between the cornea and the external environment. Corneal sensory nerves protect the cornea from injury by triggering tearing and blink reflexes, and are also thought to regulate corneal epithelial renewal via unknown mechanism(s). When protective corneal sensory innervation is absent due to infection, trauma, intracranial tumors, surgery, or congenital causes, permanent blindness results from repetitive epithelial microtraumas and failure to heal. The condition is termed neurotrophic keratopathy (NK), with an incidence of 5:10,000 people worldwide. In this report, we review the currently available therapeutic solutions for NK and discuss the progress in our understanding of how the sensory nerves induce corneal epithelial renewal.

Possible donor nerves for axillary nerve reconstruction in dual neurotization for restoring shoulder abduction in brachial plexus injuries: a systematic review and meta-analysis.

Restoring shoulder abduction is one of the main priorities in the surgical treatment of brachial plexus injuries. Double nerve transfer to the axillary nerve and suprascapular nerve is widely used and considered the best option. The most common donor nerve for the suprascapular nerve is the spinal accessory nerve. However, donor nerves for axillary nerve reconstructions vary and it is still unclear which donor nerve has the best outcome. The aim of this study was to perform a systematic review on reconstructions of suprascapular and axillary nerves and to perform a meta-analysis investigating the outcomes of different donor nerves on axillary nerve reconstructions. We conducted a systematic search of English literature from March 2001 to December 2020 following PRISMA guidelines. Two outcomes were assessed, abduction strength using the Medical Research Council (MRC) scale and range of motion (ROM). Twenty-two studies describing the use of donor nerves met the inclusion criteria for the systematic review. Donor nerves investigated included the radial nerve, intercostal nerves, medial pectoral nerve, ulnar nerve fascicle, median nerve fascicle and the lower subscapular nerve. Fifteen studies that investigated the radial and intercostal nerves met the inclusion criteria for a meta-analysis. We found no statistically significant difference between either of these nerves in the abduction strength according to MRC score (radial nerve 3.66 ± 1.02 vs intercostal nerves 3.48 ± 0.64, p = 0.086). However, the difference in ROM was statistically significant (radial nerve 106.33 ± 39.01 vs. intercostal nerve 80.42 ± 24.9, p < 0.001). Our findings support using a branch of the radial nerve for the triceps muscle as a donor for axillary nerve reconstruction when possible. Intercostal nerves can be used in cases of total brachial plexus injury or involvement of the C7 root or posterior fascicle. Other promising methods need to be studied more thoroughly in order to validate and compare their results with the more commonly used methods.

Neurotization Does not Prolong Operative Time in Free Flap Breast Reconstruction.

BACKGROUND: Neurotization during the breast reconstruction process can improve patient quality-of-life and satisfaction with reconstructive outcomes. One concern with neurotization is increased total operative time due to the need for additional dissection and nerve coaptation. The purpose of this study was to compare total operative time between neurotized and non-neurotized abdominal-based, free flap breast reconstruction. METHODS: A retrospective review was conducted of consecutive patients who underwent unilateral, abdominal-based, free flap breast reconstruction between 2016 and 2018 at a single tertiary care center. Data were collected on patient demographics, surgical techniques, and length of surgery. Data analysis was performed using chi-square test, independent t-test, and multivariate linear regression analysis. A p-value ≤0.05 was considered statistically significant. RESULTS: Seventy-three patients were included in this study. Twenty-three patients (31.50%) underwent flap neurotization (N group) and 50 (68.49%) underwent standard breast reconstruction without neurotization (NO group). The groups were similar in age, BMI, smoking status, and ASA class. No difference was found between the two groups in timing of reconstruction (p = 0.388). Average operative times were 467.73 ± 145.52 minutes and 455.28 ± 111.19 minutes for the N and NO groups, respectively, with no significant difference between the two groups (two-tailed p-value = 0.72). CONCLUSION: Seamless integration of neurotization in abdominal-based, free flap breast reconstruction is possible without significant prolongation of total operative time. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

[Modification of intercostobrachial neurotization of musculocutaneous and axillary nerves in total brachial plexopathy: description of technique and literature review]. / Modifikatsiya interkostobrakhial'noi nevrotizatsii myshechno-kozhnogo i podmyshechnogo nervov pri total'noi brakhiopleksopatii: opisanie metodiki i obzor literatury.

BACKGROUND: Intercostobrachial neurotization is one of the few approach for partial motor recovery of extremity in patients with total trauma of brachial plexus. However, direct coaptation with musculocutaneous nerve is often impossible due to different anatomy of intercostal nerves and their functional failure at several levels. This necessitates the use of intermediate graft that deteriorates the final outcome. OBJECTIVE: To develop an alternative method for direct coaptation of musculocutaneous nerve with insufficiently long intercostal donor nerves. MATERIAL AND METHODS: The study included 26 patients with total post-traumatic plexitis. All patients underwent intercostobrachial neurotization of musculocutaneous and axillary nerves. Original technique of direct selective neurotization of motor fascicular groups of musculocutaneous and axillary nerves was used in 11 cases. RESULTS AND DISCUSSION: A modified variant of intercostobrachial neurotization of musculocutaneous and axillary nerves consists in mobilization and transposition of recipient nerves in axillary region. This makes it possible to reduce the distance to donor nerves and, in most cases, to carry out direct neurotization without autologous grafts. Among 11 patients, restoration of shoulder abduction and elbow flexion was obtained in 7 patients (77 %). CONCLUSION: The proposed adaptive technique makes it possible to avoid graft lengthening in some cases and provides satisfactory results.

[Treatment of neurotrophic keratopathy in combined lesions of the trigeminal and facial nerves]. / Lechenie neirotroficheskoi keratopatii pri sochetannom porazhenii troinichnogo i litsevogo nervov.

Ocular symptomatology in lesions of the facial nerve is associated with disturbed innervation of the circular muscle of the eye that leads to disruption of the protective function of the eyelids and the development of exposure symptoms, and is accompanied by a breach in corneal tear film integrity. The main clinical manifestation of the trigeminal nerve damage is the loss of sensory innervation of the cornea and disruption of the supply of neurotransmitters to its cells, manifesting as corneal hypo- or anesthesia. This triggers a cascade of pathological processes that lead to the development of neurotrophic keratopathy. In combined pathology of the facial and trigeminal nerves, a number of interrelated and mutually aggravating problems arise that require correction of lagophthalmos and functional restoration of the trigeminal nerve, since there is an interaction between the corneal epithelium and trigeminal neurons through trophic neuromodulators, which normally contribute to the proliferation of epithelial cells, their differentiation, migration and adhesion, and are essential for vital functions, metabolism and healing of surface lesions of the eye. Classical methods of treating neurotrophic keratopathy aim to protect the ocular surface, and are palliative or auxiliary, do not provide radical relief of the symptoms of neurotrophic keratopathy. Modern surgical technique of neurotization of the cornea allows restoring the structural growth of the nerve, which provides nerve trophism and corneal sensitivity, and is the only pathogenetically substantiated method of effective treatment of neurotrophic keratopathy. At the same time, direct neurotization has undeniable advantages over methods involving intercalary donor nerves, since neuropeptides from nerve fibers are immediately released into the recipient tissue and start reparative processes. Taking into account the accumulated positive experience of neurotization surgeries, scientific and clinical research should be continued in order to improve the most effective methods of corneal neurotization and promote their wider implementation into clinical practice.

[Modern capabilities in diagnosis and treatment of neurotrophic keratopathy]. / Sovremennye vozmozhnosti diagnostiki i lecheniya neirotroficheskoi keratopatii.

In recent years, the problem of diagnosing and treating neurotrophic keratopathy (NK) has become relevant in view of its prevalence reaching 1.6-11.0 per 10000 people. While previously it was associated only with neuroparalytic keratitis, at present the violation of sensitive and trophic innervation of the cornea with the development of characteristic keratopathy is observed in many diseases and injuries of the organ of vision. Diagnosis of NK is based on anamnestic information and assessment of clinical and functional parameters: determination of the stability of the tear film, tear production and assessment of staining of the ocular surface with vital dyes. The main role in the diagnosis of NK belongs to corneal sensitivity determined with the Cochet-Bonnet esthesiometer. Treatment of NK is designed to restore or increase corneal sensitivity and involves tear replacement therapy, instillations of preparations derived from patient's own blood, anti-inflammatory, metabolic and antibacterial therapy. However, instillations of human erve growth factor (NGF) - the drug Cenegermin (registered in Europe in 2017 at a dose of 20 µg/ml under the name Oxervate), a recombinant form of human rhNGF from Escherichia coli bacteria - exhibit the highest pathogenetic orientation. Its «target¼ is the affected nerve fibers (specific receptors for their growth factor), which makes it possible to eliminate the violation of reparative processes in neural and epithelial cells. A high and long-term clinical efficacy of a course of six (with an interval of 2 hours) instillations of the drug for 8 weeks in the treatment of children and adults with NK has been established. Among the pathogenetically justified methods of surgical treatment, there is the so-called surgical neurotization of the cornea involving the contralateral supraorbital, supratrochlear, great auricular and other nerves, which has a long-term clinical effect.

The role of neurotization in autologous breast reconstruction: Can reconstruction restore breast sensation?

As the sophistication of microsurgical breast reconstruction continues to evolve, plastic surgeons are focusing on techniques to improve functional and psychosocial outcomes for patients, including breast sensation. Interest in neurotization of breast flaps, among both patients and surgeons, has grown significantly in recent years. This study aimed to review the outcomes of neurotization across autologous flap reconstructions, to provide a comprehensive analysis of the efficacy of this technique in improving postoperative sensory recovery.

Nerve transfers for acute flaccid myelitis: a case series.

BACKGROUND: Acute flaccid myelitis (AFM) syndrome consists of loss of lower motor neurons following a viral infection, with preserved sensory function. It usually affects the upper limbs asymmetrically, with proximal more than distal muscle involvement. METHODS: Five cases were surgically treated with nerve transfers: spinal accessory to suprascapular nerve transfer (4 patients), branch of radial nerve to axillary nerve transfer (Somsak's procedure) (2 patients), and transfer of a fascicle of the ulnar nerve to the motor branch to the biceps (Oberlin's procedure) (1 patient). RESULTS: Motor improvement was seen in three cases. Widespread motor involvement was associated with poor outcome. CONCLUSION: This small series of cases reinforces that nerve transfers are a reliable option for treatment of selected children with AFM.

Distal nerve transfer for thenar palsy: A cadaveric study.

INTRODUCTION: Severe proximal median nerve palsies often result in irreversible thenar atrophy and thumb abduction function loss. Tendon transfer involves substantial limitations and challenges; but, distal nerve transfer may provide an alternative treatment. Our goal was to validate the anatomical suitability of two distal ulnar nerve branches for thenar muscle reanimation. MATERIALS AND METHODS: We assessed nerve transfer to the recurrent branch of median nerve (RMN) in 16 embalmed cadaveric hands. The ulnar motor branch to the flexor digiti minimi brevis (FDMBn) and the ulnar motor branch to the third lumbrical (3rdLn) were assessed for transfer. Coaptation success was measured by the overlap of the nerve donor with the RMN and correspondence of nerve diameters. RESULTS: The mean transferable length and width of the RMN were 20.7 ± 4.5 and 1.0 ± 0.3 mm, respectively. We identified an average of three branches in the branching anatomy from the ulnar nerve to the hypothenar muscles. The maximal transferable lengths and widths of the FDMBn and the 3rdLn were 13.8 ± 4.4 and 0.5 ± 0.1 mm and 24.1 ± 6.4 and 0.4 ± 0.1 mm, respectively. The overlap with the RMN of the FDMBn and 3rdLn was 9.0 ± 3.6 (2.0-15.3) and 17.8 ± 6.0 (4.7-27.5) mm, respectively. CONCLUSIONS: This anatomical study demonstrates the feasibility of distal nerve transfers between the ulnar and median nerves in the hand for reanimation of thenar muscles. Ulnar motor donors of the BrFDMBn and 3rdLn likely represent the least morbid donors with short distances for regeneration and a single coaptation repair.

In Vivo Corneal Confocal Microscopy: Pre- and Post-operative Evaluation in a Case of Corneal Neurotization.

In this report, we analyse the pre- and post-operative corneal changes observed using in vivo confocal corneal microscopy in a patient with neurotrophic keratitis submitted to a corneal reinnervation surgical procedure. We describe favourable trophic changes observed at different levels of the patient's cornea, particularly in the sub-basal nerve plexus; complete absence of these neurological structures was observed before surgery, but appeared largely restored six months thereafter.

[Selective neurotization of the median nerve in young patients with CV-CVIIcomplicated spinal cord injury]. / Selektivnaya nevrotizatsiya sredinnogo nerva u molodykh patsientov s oslozhnennoi pozvonochno-spinnomozgovoi travmoi na urovne CV­CVII.

BACKGROUND: Complicated spinal cord injury occurs in 1-5 cases per 100.000. In children, cervical trauma makes up 72% of all spinal trauma. Spinal cord injury complicates vertebral trauma in 25-50% of cases that usually results severe disability. Rehabilitation of these patients is usually ineffective or results a little improvement. Restoration of even minimal movements is essential in these patients. There are reports devoted to surgical rehabilitation of important hand functions after cervical spinal cord injury. OBJECTIVE: To demonstrate the restoration of key hand functions in patients with CV-CVII complicated spinal cord injury using selective neurotization of the median nerve. MATERIAL AND METHODS: Three patients aged 17-19 years with complicated CV-CVII spinal cord injury and ASIA class A have been selected for surgery for 2 years. Mean period after rehabilitation was 11.3 months. Prior to surgery, all patients recovered flexion/extension in the elbow joints, forearm rotation, flexion and extension of hands. However, there were no active movements in distal phalanges of the fingers, and initial signs of flexor contracture were observed. RESULTS: Surgical strategy included selective neurotization of the median nerve with a motor branch of musculocutaneous nerve. In one case, we used additional neurotization of posterior interosseous nerve. Two patients recovered cylindrical grip up to M4 and pinch grip up to M3 within 15 months. In the third patient, postoperative data were not assessed due to short-term follow-up. CONCLUSION: Selective neurotization of anterior interosseous nerve may be considered as a stage or independent surgery for restoration of key hand functions. This approach improves the quality of life in patients with complicated spinal cord injury.

[Neurotization of the cornea as pathogenically targeted method of treating neurotrophic keratitis in patients with facial paralysis]. / Nevrotizatsiya rogovitsy kak patogeneticheski napravlennyi metod lecheniya neirotroficheskogo keratita u patsientov s litsevym paralichom.

Combined lesions of the facial and trigeminal cranial nerves are typical after neurosurgical treatment. Violation of the innervation of orbicularis muscle leads to inability to completely close the eyelids, while denervation of the cornea is often manifested as a long-term ongoing and recurring neurotrophic keratitis. The restoration of corneal innervation is a pathogenetically targeted treatment for this pathology. For this purpose, neurotrophic keratitis could be reversed via the method of corneal neurotization using contralateral n. ophthalmicus. The presented clinical case demonstrates the results of the first operation of neurotization of the cornea in a patient with combined lesions of the facial and trigeminal nerves.

[EMOTIONAL EXHAUST AS A FACTOR OF THE ORIGIN AND DEVELOPMENT OF NEUROTIC CONDITIONS OF MEDICAL WORKERS].

The purpose of the study is to determine the specifics of neurotization of medical workers with emotional exhaust. Out of 6,830 medical workers surveyed, 1,012 were selected with severe emotional exhaust in order to further determine their specificity of neurotization. Used: Maslach Burnout Inventory questionnaire (MBI), modification of Maslach Burnout Inventory questionnaire (mod MBI), burnout questionnaire (BQ), neurotic level diagnosis technique (NLDT), clinical questionnaire for identifying and evaluating neurotic conditions (CQIENC), symptomatic questionnaire (SQ). Mathematical and statistical processing included descriptive statistics, C. Pearson's correlation criterion, and Cheddock's table for determining the tightness (strength) of correlation (weak - <0.3, moderate - 0.3-0.5, noticeable - 0.5-0.7, high - 0.7-0.9, very high - >0.9). Medical professionals with a higher than average level with a tendency to a high level of emotional exhaust (51.64) and emotional burnout (270.14) are dominated by stress (109.17), experience of traumatic circumstances (28.65), dissatisfaction with oneself (26.05), driving into a cell (29.10), anxiety and depression (25.37), which determine above the average level of anxiety ( 4.35, high connection 0.80), asthenia (4.20, high connection 0.74), anxiety, tension (51.57, high connection 0.76), neurotic disorders (40.28, high 0.74), hypochondriacal disorders (29.04, high connection 0.74), psychasthenic disorders (37.53, 0.76 high connection). The specifics of neurotization of medical workers with emotional exhaust affects, first of all, the emotional-volitional sphere, which gives grounds to recommend medical workers a systematic diagnosis and prevention of emotional exhaust as a component of professional deformations of medical workers.

[Multivisceral resection of lipoblastoma of four anatomical areas of the head and neck with simultaneous neurotization of the facial muscles in an 8-months child. Clinical case]. / Polivistseral'naya rezektsiya lipoblastomy chetyrekh anatomicheskikh oblastei golovy i shei s odnomomentnoi nevrotizatsiei myshts litsa u rebenka 8 mesyatsev. Klinicheskii sluchai.

The article describes diagnostics and surgical treatment of a rare benign tumor (lipoblastoma) of four anatomical areas of the head and neck in an 8-months child. Diagnostic data, surgical procedure performed using microsurgical techniques and intraoperative neuromonitoring and the patient's condition in the long-term postoperative period are presented. The histological conclusion about the removal of the tumor with negative resection margins suggests favorable prognosis of the disease.

Dual innervation may occur in a partially denervated muscle.

INTRODUCTION: With a view to simplifying surgical techniques for selective laryngeal reinnervation, we addressed the question of whether it is feasible to receive additional innervation by a partially denervated muscle using an infrahyoid muscle model. METHODS: In 90 rats (6 groups of 15), phrenic nerve transfer was used to reinnervate the sternothyroid muscle. In some cases, residual innervation by the original nerve was present. Three months later we performed electromyographic studies, contraction strength measurements, histologic assessment, and retrograde labeling. RESULTS: Muscles reinnervated by the phrenic nerve had a greater "dual-response" rate (in terms of nerve latency, contraction strength, and retrograde labeling) than muscles in the control groups. DISCUSSION: The phrenic nerve can impart its inspiratory properties to an initially denervated strap muscle-even when residual innervation is present. The preservation of contractile potential confirmed the feasibility of dual innervation in a previously injured muscle. Muscle Nerve 59:108-115, 2019.

Proposed surgical technique to facilitate targeted reinnervation of the infraspinatus: A cadaveric feasibility study.

Restoration of shoulder lateral rotation remains a significant challenge following brachial plexus injury. Transfer of the accessory nerve to suprascapular nerve (SSN) has been widely performed, although with generally poor outcomes for lateral rotation. A recent report suggested a selective infraspinatus reinnervation technique using a radial nerve branch for SSN transfer. This cadaveric study was performed in 7 specimens (14 shoulders). We present technical modifications to achieve additional length to the recipient nerve (suprascapular) that would facilitate direct repair. Key elements of the technique are (1) isolation of the SSN immediately distal to its motor branch to supraspinatus near the superior transverse scapular ligament; and (2) delivery of the transected SSN through the spinoglenoid notch and deep to the infraspinatus for emergence in the infraspinatus-teres minor interval. Nerve overlap of at least 21 mm was observed in all 14 dissected shoulders between the harvested SSN and radial nerve branches. The mean nerve overlap between harvested branches was 26 mm (range 21-32 mm). The mean harvested SSN length was 59 mm (range 46-80 mm). The mean length of the harvested radial nerve branch was 72 mm (range 65-85 mm). No measurements were significantly different between left and right shoulders or between males and females (smallest P value = 0.1249). Nerve diameter of the two harvested branches was judged to be appropriately compatible for surgical coaptation in all 14 dissected shoulders. We present a variation on a described technique to increase recipient suprascapular nerve length. Additional length of the recipient nerve is achieved through utilization of a more proximal dissection of the suprascapular nerve near the level of the superior transverse scapular ligament and delivering the nerve through the teres minor-infraspinatus interval. These surgical modifications are of clinical interest when selective reinnervation of the infraspinatus muscle is considered. We believe such a targeted approach can potentially increase shoulder lateral rotation function. Clin. Anat. 32:131-136, 2019. © 2018 Wiley Periodicals, Inc.