Cell Types Promoting Goosebumps Form a Niche to Regulate Hair Follicle Stem Cells.

Piloerection (goosebumps) requires concerted actions of the hair follicle, the arrector pili muscle (APM), and the sympathetic nerve, providing a model to study interactions across epithelium, mesenchyme, and nerves. Here, we show that APMs and sympathetic nerves form a dual-component niche to modulate hair follicle stem cell (HFSC) activity. Sympathetic nerves form synapse-like structures with HFSCs and regulate HFSCs through norepinephrine, whereas APMs maintain sympathetic innervation to HFSCs. Without norepinephrine signaling, HFSCs enter deep quiescence by down-regulating the cell cycle and metabolism while up-regulating quiescence regulators Foxp1 and Fgf18. During development, HFSC progeny secretes Sonic Hedgehog (SHH) to direct the formation of this APM-sympathetic nerve niche, which in turn controls hair follicle regeneration in adults. Our results reveal a reciprocal interdependence between a regenerative tissue and its niche at different stages and demonstrate sympathetic nerves can modulate stem cells through synapse-like connections and neurotransmitters to couple tissue production with demands.

Advancing glenohumeral dysplasia treatment in brachial plexus birth injury: the end-to-side spinal accessory to suprascapular nerve transfer technique.

PURPOSE: Brachial plexus birth injury (BPBI) is a common injury with the spectrum of disease prognosis ranging from spontaneous recovery to lifelong debilitating disability. A common sequela of BPBI is glenohumeral dysplasia (GHD) which, if not addressed early on, can lead to shoulder dysfunction as the child matures. However, there are no clear criteria for when to employ various surgical procedures for the correction of GHD. METHODS: We describe our approach to correcting GDH in infants with BPBIs using a reverse end-to-side (ETS) transfer from the spinal accessory to the suprascapular nerve. This technique is employed in infants that present with GHD with poor external rotation (ER) function who would not necessitate a complete end-to-end transfer and are still too young for a tendon transfer. In this study, we present our outcomes in seven patients. RESULTS: At presentation, all patients had persistent weakness of the upper trunk and functional limitations of the shoulder. Point-of-care ultrasounds confirmed GHD in each case. Five patients were male, and two patients were female, with a mean age of 3.3 months age (4 days-7 months) at presentation. Surgery was performed on average at 5.8 months of age (3-8.6 months). All seven patients treated with a reverse ETS approach had full recovery of ER according to active movement scores at the latest follow-up. Additionally, ultrasounds at the latest follow-up showed a complete resolution of GHD. CONCLUSION: In infants with BPBI and evidence of GHD with poor ER, end-to-end nerve transfers, which initially downgrade function, or tendon transfers, that are not age-appropriate for the patient, are not recommended. Instead, we report seven successful cases of infants who underwent ETS spinal accessory to suprascapular nerve transfer for the treatment of GHD following BPBI.

Selective nerve transfers to restore shoulder abduction and flexion in acute flaccid myelitis: A case report.

Acute flaccid myelitis (AFM) is a polio-like condition predominantly affecting children that is characterized by acute-onset, asymmetric flaccid paralysis, often preceded by a prodromal fever or viral illness. With prompt diagnosis and early surgical referral, nerve transfers may be performed to improve function. Highly selective nerve transfers are ideal to preserve existing functions while targeting specific deficits. In this report, we present a case of a double fascicular nerve transfer of median and ulnar nerve fascicles to the axillary nerve, combined with selective transfer of the spinal accessory nerve to the supraspinatus branch of the suprascapular nerve, performed for a 5-year-old girl who developed AFM after an upper respiratory infection. Six months after the onset of the patient's symptoms, the patient had continued weakness of shoulder flexion and abduction, atrophy of the deltoid, and supraspinatus muscles, though needle electromyography revealed a functioning infraspinatus muscle. The patient had no post-operative complications and at 2 years of postoperative follow up achieved shoulder abduction and flexion Active Movement Scale scores of 7/7 compared to preoperative scores of 2/7, with no loss of function in the donor nerve domains. The patient showed active shoulder abduction against gravity to 90° from 30° preoperatively and shoulder flexion to 180° from 15° preoperatively. This case report shows that highly selective nerve transfers may preserve existing functions while targeting specific deficits. A double fascicular transfer from the median and ulnar nerves to axillary nerve may provide abundant axons for functional recovery.

Functional and morphological evaluation of the trapezius muscle after spinal accessory nerve transfer to brachial plexus nerves.

INTRODUCTION: The main innervation of the trapezius muscle is provided by the spinal accessory nerve. Several studies describe the contributions of cervical plexus roots to the trapezius muscle innervation, either directly or through connections with the spinal accessory nerve. There is no adequate understanding of how the trapezius muscle is affected after using the spinal accessory nerve in nerve transfer procedures with the usual technique, preserving at least 1 branch for the upper trapezius. METHODS: We evaluated 20 patients with sequelae of traumatic brachial plexus injury who underwent surgical procedures for brachial plexus repair or free muscle transfer, which included the spinal accessory nerve transfer technique and were followed for a minimum of 1 year. The three portions trapezius muscle were evaluated by physical examination, magnetic resonance imaging (analysis of fatty degeneration) and electromyography. RESULTS: In all evaluation methods, the middle and lower portions of the trapezius muscle showed more significant morphological and/or functional impairment than the upper portion, in most cases. There was a statistically significant difference in all the complementary exams results, between the affected side (with sacrifice of the nerve) versus the normal side, in the middle and lower portions of the trapezius muscle. CONCLUSIONS: Physical examination alone is not sufficient to determine the residual functionality of the trapezius muscle. Magnetic resonance imaging and electromyography are useful tools to assess both morphological involvement of the trapezius muscle and nerve conduction impairment of the trapezius muscle, respectively. The results suggest that the middle and lower portions of the trapezius muscle are affected by previous SAN transfer and should be considered with caution for further muscle transfer procedures.

Spinal accessory nerve anatomy in the posterior cervical triangle: A systematic review with meta-analysis.

This study aimed to investigate the anatomy of the spinal accessory nerve (SAN) in the posterior cervical triangle, especially in relation to adjacent anatomical landmarks, along with a systematic review of the current literature with a meta-analysis of the data. Overall, 22 cadaveric and three prospective intraoperative studies, with a total of 1346 heminecks, were included in the analysis. The major landmarks relevant to the entry of the SAN at the posterior border of the SCM muscle (PBSCM) were found to be the mastoid apex, the great auricular point (GAP), the nerve point (NP), and the point where the PBSCM meets the upper border of the clavicle. The SAN was reported to enter the posterior cervical triangle above GAP in 100% of cases and above NP in most cases (97.5%). The mean length of the SAN along its course from the entry point to its exit point from the posterior triangle of the neck was 4.07 ± 1.13 cm. The SAN mainly gave off 1 or 2 branches (32.5% and 31%, respectively) and received either no branches or one branch in most cases (58% and 23%, respectively) from the cervical plexus during its course in the posterior cervical triangle. The major landmarks relevant to the entry of the SAN at the anterior border of the TPZ muscle (ABTPZ) were found to be the point where the ABTPZ meets the upper border of the clavicle and the midpoint of the clavicle, along with the mastoid apex, the acromion, and the transverse distance of the SAN exit point to the PBSCM. The results of the present meta-analysis will be helpful to surgeons operating in the posterior cervical triangle, aiding the avoidance of the iatrogenic injury of the SAN.

Computed tomographic features of canine intracranial and jugular foraminal masses involving the combined glossopharyngeal, vagus, and accessory nerve roots.

A chronic cough, gag, or retch is a common presenting clinical complaint in dogs. Those refractory to conservative management frequently undergo further diagnostic tests to investigate the cause, including CT examination of their head, neck, and thorax for detailed morphological assessment of their respiratory and upper gastrointestinal tract. This case series describes five patients with CT characteristics consistent with an intracranial and jugular foraminal mass of the combined glossopharyngeal (IX), vagus (X), and accessory (XI) cranial nerves and secondary features consistent with their paresis. The consistent primary CT characteristics included an intracranial, extra-axial, cerebellomedullary angle, and jugular foraminal soft tissue attenuating, strongly enhancing mass (5/5). Secondary characteristics included smooth widening of the bony jugular foramen (5/5), mild hyperostosis of the petrous temporal bone (3/5), isolated severe atrophy of the ipsilateral sternocephalic, cleidocephalic, and trapezius muscles (5/5), atrophy of the ipsilateral thyroarytenoideus and cricoarytenoideus muscles of the vocal fold (5/5), and an ipsilateral "dropped" shoulder (4/5). Positional variation of the patient in CT under general anesthesia made the "dropped" shoulder of equivocal significance. The reported clinical signs and secondary CT features reflect a unilateral paresis of the combined cranial nerves (IX, X, and XI) and are consistent with jugular foramen syndrome/Vernet's syndrome reported in humans. The authors believe this condition is likely chronically underdiagnosed without CT examination, and this case series should enable earlier CT diagnosis in future cases.

Anatomical variations in the course of spinal accessory nerve in the neck triangles: A descriptive study.

BACKGROUND: Spinal Accessory Nerve (SAN), which innervates the sternocleidomastoid (SCM) and trapezius muscles, is closely related to the internal jugular vein (IJV) in the anterior triangle of the neck and passes superficially in the posterior triangle. Injury to SAN is a major complication of level II neck dissection, leading to shoulder syndrome. The present study aims to assess the course and its relation to the SCM muscle and IJV in the Tamil ethnolinguistic groups in South India. METHODS AND MATERIALS: The anterior and posterior triangles of the neck were dissected in 28 formalin-fixed adult cadavers. The course of the SAN and the entry and exit points of SAN along the SCM muscle were assessed using the mastoid process as the reference. Recorded data was analyzed using SPSS software. RESULTS: The SAN was anteriorly related to the IJV in 58.73%, posteriorly in 37.5%, and pierced through the IJV in 3.57% of the specimens. The entry and exit points of SAN from the mastoid process were 37.86±7.26mm and 48.55±8.22mm, respectively. In 86.67% of the cases, the SAN traversed through the SCM muscle, and in 13.33%, it was deep to the SCM. CONCLUSION: The present study reports that the SAN is variable in its course, and relation to SCM and IJV. Knowledge about the variant anatomy of the SAN in the triangles of the neck is important and it aids surgeons to prevent iatrogenic injuries to SAN or IJV and enhance surgical safety in neck procedures.

Post-operative progress of arm abduction function and rate of lymph node metastasis around the region of the accessory nerve: a multicentre prospective observational study.

OBJECTIVE: Although neck dissection is an essential technique in the surgical treatment of head and neck carcinoma, arm abduction disorders occurring after neck dissection reduce the patient's quality of life. METHODS: We prospectively evaluated the rate of lymph node metastasis in Levels IIB and V in head and neck cancer patients who underwent neck dissection at eight centres in Japan. In addition, post-operative arm abduction disability was classified according to functional assessment values at 1 month post-operatively, and the rate of maintained function at 6 and 12 months was evaluated. RESULTS: Lymph node metastasis occurred in Level IIB in 12 of 242 cases (4.9%) and in Level V in 5 cases (2.1%) during the 12-month post-operative course. In patients with preservation of the ipsilateral accessory nerve, arm abduction function was maintained in 142 of 209 patients (67.9%) at 12 months after surgery. Post-operative radiotherapy and Level V dissection had no statistically significant effect on the recovery of arm abduction function. Level V dissection caused a temporary loss of abduction function post-operatively. A higher arm abduction test score at 1 month post-operatively was associated with a higher rate of subsequent ability to maintain arm abduction function. CONCLUSIONS: In patients classified as cN0, metastatic rate at Levels IIB and V was low. In this cohort, omitting Level V dissection may be an option in strategies aimed at maintaining arm abduction function.

Phrenic Nerve as an Alternative Donor for Nerve Transfer to Restore Shoulder Abduction in Severe Multiple Root Injuries of the Adult Brachial Plexus.

PURPOSE: Nerve transfer is the gold standard to restore shoulder abduction in acute brachial plexus injuries. The aim of this study was to compare the phrenic nerve (Ph) to the spinal accessory nerve (XI) as the donor nerve for this purpose. METHODS: A retrospective chart review was performed on 136 patients with acute brachial plexus injuries who received a nerve transfer of the shoulder with either the Ph (94 patients) or XI (42 patients). Each group was divided into 3 subgroups based on the recipient nerve. The maximum degree of shoulder abduction was recorded after 2 years of postoperative follow-up. A generalized estimating equation model was performed to examine the variables affecting shoulder abduction over time. RESULTS: The maximum degrees of shoulder abduction achieved were 61.9° ± 38.7° in patients with Ph and 51.1° ± 37.3° in patients with XI. More than M3 shoulder abduction was achieved by 67% of patients with Ph versus 59% of patients with XI. The regression analysis showed that the age at the time of surgery correlated more with the functional outcome over time than the choice of donor nerve. CONCLUSIONS: In multiple root brachial plexus injuries, the Ph exhibited similar outcomes to the XI for shoulder abduction. Our routine exploration of the supraclavicular plexus exposes the Ph conveniently for nerve transfer. The phrenic nerve should be considered as an alternative when the XI is not available or is reserved for secondary reconstruction. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Sonographic reference values of cranial nerve size: A systematic review and meta-analysis.

INTRODUCTION/AIMS: Ultrasonography of the cranial nerves has recently gained attention for assessment of inflammatory, compressive, or degenerative neuropathies. However, sonographic reference values of cranial nerves have received less attention than those of peripheral nerves. In this systematic review and meta-analysis we aimed to provide current evidence of sonographic reference values for cranial nerve size. METHODS: By searching Medline (via PubMed), Scopus, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), and Web of Science, we conducted a systematic review and meta-analysis of studies that reported ultrasound measurements of the facial, spinal accessory, and hypoglossal nerves in healthy adults. We included studies that reported either the sonographic cross-sectional area (CSA) or the nerve diameter; the included nerves were subgrouped according to the site of nerve measurement. RESULTS: Fourteen studies with a total of 661 participants and 1437 ultrasound nerve measurements met the inclusion criteria. The anatomical sites for each nerve were combined to provide single-nerve mean measurements. We found an overall mean nerve diameter of 0.80 mm for the facial nerve, 0.63 mm for the spinal accessory nerve, and 1.82 mm2 for hypoglossal nerve CSA. DISCUSSION: This meta-analysis provides reference values for the diameter and cross-sectional area of the facial, spinal accessory, and hypoglossal nerves at different sites, which can be used as guidance in clinical practice to detect pathological changes in cranial nerve size in cranial neuropathies. We recommend further validation in large-scale studies as well as standardization of the scanning protocols.

A randomized controlled trial of scapular exercises with electromyography biofeedback in oral cancer patients with accessory nerve dysfunction.

PURPOSE: This study aims to investigate the effects of electromyography (EMG) biofeedback on scapular positions and muscle activities during scapular-focused exercises in oral cancer patients with accessory nerve dysfunction. METHODS: Twenty-four participants were randomly allocated to the motor-control with biofeedback group (N = 12) or the motor-control group (N = 12) immediately after neck dissection. Each group performed scapular-focused exercises with conscious control of scapular orientation for 3 months. EMG biofeedback of upper trapezius (UT), middle trapezius (MT), and lower trapezius (LT) was provided in the motor-control with biofeedback group. Scapular symmetry measured by modified lateral scapular slide test; shoulder pain; active range of motion (AROM) of shoulder abduction; upper extremity function; maximal isometric muscle strength of UT, MT, and LT; and muscle activities during arm elevation/lowering in the scapular plane were evaluated at baseline and the end of the intervention. RESULTS: After the 3-month intervention, only the motor-control with biofeedback group showed improving scapular symmetry. Although both groups did not show significant improvement in shoulder pain, increased AROM of shoulder abduction and muscle strength of the UT and MT were observed in both groups. In addition, only the motor-control with biofeedback group had improved LT muscle strength, upper extremity function, and reduced UT and MT muscle activations during arm elevation/lowering. CONCLUSIONS: Early interventions for scapular control training significantly improved shoulder mobility and trapezius muscle strength. Furthermore, by adding EMG biofeedback to motor-control training, oral cancer patients demonstrated greater effectiveness in stabilizing scapular position, muscle efficiency, and upper extremity function than motor-control training alone. TRIAL REGISTRATION: Institutional Review Board: This study was approved by the Chang Gung Medical Foundation Institutional Review Board (Approval No: 201901788A3. Approval Date: 2 January, 2020). CLINICAL TRIAL REGISTRATION: This trial was registered at ClinicalTrials.gov (ClinicalTrials.gov ID: NCT04476004. Initial released Date: 16 July, 2020).

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.

Triceps to teres minor motor nerve transfer to restore glenohumeral external rotation after neonatal brachial plexus injury.

INTRODUCTION: Attaining active glenohumeral external rotation (aGHER), whether via primary reconstruction or spontaneous recovery, is infrequent in patients with neonatal brachial plexus palsy (NBPI). We evaluated the effectiveness of triceps-to-teres minor motor branch transfers to restore this function, both performed primarily (i.e., in conjunction with microsurgical plexus reconstruction) or secondarily (after primary surgery has failed to restore aGHER). PATIENTS AND METHODS: This was a retrospective study of 12 children with NBPI undergoing triceps-to-teres minor motor branch transfer via an axillary approach, six undergoing primary surgery and six secondary. The primary outcome was post-operative restoration of aGHER in abduction. The primary-surgery group consisted of six children of mean age 8 months (range 5-11) with partial injuries ranging from C5-C6 to C5-C8. The secondary-surgery group included six patients with C5-C6 injuries of mean age 43 months (range 23-120), undergoing re-operation a mean 40 months (range 18-116) after their primary surgery. RESULTS: No complications occurred after surgery. At a mean follow-up of 22 months (range 14-30), aGHER in abduction only was restored in one patient in the primary group while in the secondary group, aGHER in abduction was restored in all patients to a mean 73° (range 70-80) after a mean follow-up of 16 months (range 6-26). CONCLUSIONS: Triceps-to-teres minor motor branch transfer is not indicated as primary surgery for NBPI. However, they can be effective in children in whom primary surgery has failed to restore aGHER, even if the spinal accessory nerve is unavailable for transfer to the infraspinatus motor branch.

High bilateral fenestration of the internal jugular vein.

Duplications and fenestrations of the internal jugular vein (IJV) are rare anatomic variations. There were previously found mostly unilateral fenestrated internal jugular veins, either empty, or traversed by the spinal accessory nerves. It was documented the computed tomography angiogram of a 65 year-old female patient and bilateral high fenestrations of the IJVs were found. On both sides, the superior ends of the fenestrations were in the jugular foramina. On the right side the fenestration had 3.8 cm length and was located in front of the transverse processes of the first two cervical vertebrae. On the opposite side the fenestration had 1.5 cm length and was antero-lateral to the transverse process of the atlas vertebra. On both sides the antero-medial arms of the fenestrations received the inferior petrosal sinuses and anterior condylar veins. Such highly placed fenestrations of the IJVs should be carefully documented either preoperatively, or prior to central venous access.

Impairment of accessory nerves around major pelvic ganglion leading to overflow urinary incontinence in rats.

AIMS: To investigate the relationship between lower urinary tract function and the accessory nerve (ACN) arising from the major pelvic ganglion (MPG). METHODS: Ten-week-old male Wistar/ST rats were randomly divided into eight groups according to the type of treatment (sham or bilateral accessory nerve injury [BACNI]) and the duration of observation (3 days, 1 week, 2 weeks, or 4 weeks: Sham-3d, Sham-1w, Sham-2w, Sham-4w, BACNI-3d, BACNI-1w, BACNI-2ws, and BACNI-4w. BACNI was induced in the following manner: the ACN was crushed for 1 min (2 mm away from the MPG) using reverse-action tweezers. The same procedure was performed on both sides. On the last day of each observation period, the bladder function was measured by awake cystometry, and histological evaluation was performed. RESULTS: All rats in the Sham groups micturated normally. In the BACNI-3d and BACNI-1w groups, all rats showed symptoms of overflow urinary incontinence (OUI). This OUI improved gradually over time. The bladder's size in the BACNI group was significantly larger than that in the Sham group (p < .01). In addition, fibrosis was observed in the subserosa of the bladder of rats in BACNI groups. CONCLUSION: The BACNI model rats exhibited OUI, suggesting that ACN is involved in the lower urinary tract function. It might be possible that ACN controls the function of either the bladder, the urethra, or both.

Lower cranial nerve syndromes: a review.

The purpose of this paper is to provide a comprehensive review encompassing the syndromes associated with the lower cranial nerves (LCNs). We will discuss the anatomy of some of these syndromes and the historical contributors after whom they were named. The LCNs can be affected individually or in combination, since the cranial nerves at this level share their courses through the jugular foramen and hypoglossal canal and the extracranial spaces. Numerous alterations affecting them have been described in the literature, but much remains to be discovered on this topic. This paper will highlight some of the subtle differences among these syndromes. Symptoms and signs that have localization value for LCN lesions include impaired speech, deglutition, sensory functions, alterations in taste, autonomic dysfunction, neuralgic pain, dysphagia, head or neck pain, cardiac or gastrointestinal compromise, and weakness of the tongue, trapezius, or sternocleidomastoid muscles. To assess the manifestations of LCN lesions correctly, precise knowledge of the anatomy and physiology of the area is required. Treatments currently used for these conditions will also be addressed here. Effective treatments are available in several such cases, but a precondition for complete recovery is a correct and swift diagnosis.

Intraoperative spinal accessory nerve monitoring in neck dissections.

BACKGROUND: The identification and preservation of the spinal accessory nerve (SAN) is essential in neck surgeries due to possible complications. We report the technique to intraoperative neuromonitoring (IONM) of SAN in functional neck dissections. METHOD: SAN was monitored by needle electrodes placed on the trapezius muscle. Preoperative and postoperative nerve mapping was performed. CONCLUSION: IONM for spinal accessory nerve in patients undergoing neck dissection is a useful technique that can be valuable for neck surgeries where spinal nerve injury is at risk.

Long-Term Outcome of Phrenic Nerve Transfer in Brachial Plexus Avulsion Injuries.

INTRODUCTION: In brachial plexus injuries, useful recovery of arm function has been documented in most patients after phrenic nerve transfer after variable follow-up durations, but there is not much information about long-term functional outcomes. In addition, there is still some concern that respiratory complications might become manifest with aging. The aim of this study was to report the outcome of phrenic nerve transfer after a minimum follow-up of 5 years. PATIENTS AND METHODS: Twenty-six patients were reviewed and evaluated clinically. Age at surgery averaged 25.2 years and follow-up averaged 9.15 years. RESULTS: Shoulder abduction and external rotation achieved by transfer of phrenic to axillary nerve (or posterior division of upper trunk), combined with spinal accessory to suprascapular nerve transfer, were better than that achieved by transfer of phrenic to suprascapular nerve, combined with grafting the posterior division of upper trunk from C5, 52.3 and 45.5 degrees versus 47.5 and 39.4 degrees, respectively. There was no difference in abduction when the phrenic nerve was transferred directly to the posterior division of upper trunk or to the axillary nerve using nerve graft. Elbow flexion (≥M3 MRC) was achieved in 5 (83.3%) of 6 cases. Elbow extension M4 MRC or greater was achieved in 4 (66.6%) of 6 cases. All patients, including those who exceeded the age of 45 years and those who had concomitant intercostal nerve transfer, continued to have no respiratory symptoms. CONCLUSIONS: The long-term follow-up confirms the safety and effectiveness and of phrenic nerve transfer for functional restoration of shoulder and elbow functions in brachial plexus avulsion injuries.

A Cadaveric Study on the Utility of the Levator Scapulae Motor Nerve as a Donor for Brachial Plexus Reconstruction.

PURPOSE: The purpose of the study was to evaluate the utility of the levator scapulae motor nerve (LSN) as a donor nerve for brachial plexus nerve transfer. We hypothesized that the LSN could be transferred to the suprascapular nerve (SSN) or long thoracic nerve (LTN) with a reliable tension-free coaptation and appropriate donor-to-recipient axon count ratio. METHODS: Twelve brachial plexus dissections were performed on 6 adult cadavers, bilaterally. We identified the LSN, spinal accessory nerve (SAN), SSN, and LTN. Each nerve was prepared for transfer and nerve redundancies were calculated. Cross-sections of each nerve were examined histologically, and axons counted. We transferred the LSN to target first the SSN and then the LTN, in a tension-free coaptation. For reference, we transferred the distal SAN to target the SSN and LTN and compared transfer parameters. RESULTS: Three cadavers demonstrated 2 LSN branches supplying the levator scapulae. The axon count ratio of donor-to-recipient nerve was 1:4.0 (LSN:SSN) and 1:2.1 (LSN:LTN) for a single LSN branch and 1:3.0 (LSN:SSN) and 1:1.6 (LSN:LTN) when 2 LSN branches were available. Comparatively, the axon count ratio of donor-to-recipient nerve was 1:2.5 and 1:1.3 for the SAN to the SSN and the LTN, respectively. The mean redundancy from the LSN to the SSN and the LTN was 1.7 cm (SD, 3.1 cm) and 2.9 cm (SD, 2.8 cm), and the redundancy from the SAN to the SSN and the LTN was 4.5 (SD, 0.7 cm) and 0.75 cm (SD, 1.0 cm). CONCLUSIONS: These data support the use of the LSN as a potential donor for direct nerve transfer to the SSN and LTN, given its adequate redundancy and size match. CLINICAL RELEVANCE: The LSN should be considered as an alternative nerve donor source for brachial plexus reconstruction, especially in 5-level injuries with scarce donor nerves. If used in lieu of the SAN during primary nerve reconstruction, trapezius tendon transfer for improved external rotation would be enabled.

Complications after Functional Neck Dissection in Head and Neck Cancer Patients: An Observational, Retrospective, Single-Centre Study.

INTRODUCTION: Functional neck dissection (FND) represents a surgical procedure usually associated with less morbidity. METHODS: An observational, retrospective, analysis of patients diagnosed with any type of head and neck malignancy was designed to summarize and report the incidence of postoperative complications in patients undergoing FND including just those levels described for selective neck dissections in a tertiary university hospital between June 2016 and June 2019. RESULTS: 131 patients met the inclusion criteria. The total number of sides studied was 200. 40.5% of the patients suffer a complication in the postoperative period, being the spinal accessory nerve (SAN) injury the most common complication (10%). We did not find any statistical -correlation between the previous organ-preservation treatments and surgical complications (p = 0.207). An advanced T stage (p = 0.009) and the need of bilateral FND (p = 0.034) were significantly correlated with a higher risk of surgical complications. CONCLUSION: FND represents a useful technique. In this study, 40.5% of the patients suffer a complication in the postoperative period, being the SAN injury the most common complication. However, these data contribute to increasing our knowledge about surgical complications related to FND.