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.

A Randomised Control Trial Comparing the Outcomes of Anterior with Posterior Approach for Transfer of Spinal Accessory Nerve to Suprascapular Nerve in Brachial Plexus Injuries.

Background: In brachial plexus surgery, a key focus is restoring shoulder abduction through spinal accessory nerve (SAN) to suprascapular nerve (SSN) transfer using either the anterior or posterior approach. However, no published randomised control trials have directly compared their outcomes to date. Therefore, our study aims to assess motor outcomes for both approaches. Methods: This study comprises two groups of patients. Group A: anterior approach (29 patients), Group B: Posterior approach (29 patients). Patients were allocated to both groups using selective randomisation with the sealed envelope technique. Functional outcome was assessed by grading the muscle power of shoulder abductors using the British Medical Research Council (MRC) scale. Results: Five patients who were operated on by posterior approach had ossified superior transverse suprascapular ligament. In these cases, the approach was changed from posterior to anterior to avoid injury to SSN. Due to this reason, the treatment analysis was done considering the distribution as: Group A: 34, Group B: 24. The mean duration of appearance of first clinical sign of shoulder abduction was 8.16 months in Group A, whereas in Group B, it was 6.85 months, which was significantly earlier (p < 0.05). At the 18-month follow-up, both intention-to-treat analysis and as-treated analysis were performed, and there was no statistical difference in the outcome of shoulder abduction between the approaches for SAN to SSN nerve transfer. Conclusions: Our study found no significant difference in the restoration of shoulder abduction power between both approaches; therefore, either approach can be used for patients presenting early for surgery. Since the appearance of first clinical sign of recovery is earlier in posterior approach, therefore, it can be preferred for cases presenting at a later stage. Also, the choice of approach is guided on a case to case basis depending on clavicular fractures and surgeon preference to the approach. Level of Evidence: Level II (Therapeutic).

Shoulder function after neck dissection with level IIb preservation: a prospective observational study.

BACKGROUND: Shoulder syndrome can be reduced by preserving the spinal accessory nerve (SAN). However, it is unclear whether performing level IIb preservation will decrease the risk of SAN injury and shoulder syndrome. AIMS/OBJECTIVES: We investigated whether neck dissection with level IIb preservation can reduce shoulder dysfunction and postoperative quality of life (QOL) in head and neck cancer patients. MATERIAL AND METHODS: This prospective observational study enrolled patients who underwent neck dissection from 2011 to 2014. Patients were divided into three groups (level IIb preservation group [group 1], IIb dissection group [group 2], and IIb and V dissection group [group 3]). Postoperative shoulder function and QOL were evaluated among the three groups. RESULTS: There were a total of 35 neck sides in three groups, with nine neck sides in group 1, 16 neck sides in group 2, and 10 neck sides in group 3. Although the results showed less shoulder dysfunction in group 1 at early postoperative period. The QOL in group 1 was preserved in the early postoperative period. CONCLUSIONS AND SIGNIFICANCE: Neck dissection with level IIb preservation may help reduce shoulder syndrome and maintain QOL in the early postoperative period.

Dual spinal accessory nerve: an anatomical anomaly during neck dissection.

The spinal accessory nerve (SAN) is an important cranial nerve encountered during neck dissection. Preservation of this nerve from iatrogenic damage is crucial to avoid debilitating sequalae, which can be made challenging due to variation of its anatomical course. In this case report, we present a patient who underwent supraomohyoid neck dissection, where a rare variation of a dual SAN, traversing the internal jugular vein midway, was encountered. In this case report, we study this anatomical finding, which is undoubtedly a valuable addition to the existing knowledge of the SAN. Ultimately, allowing surgeons to develop further awareness of the variations of the SAN and contributing to favourable postoperative outcomes.

The Anterolateral Approach, Revisited for Benign Jugular Foramen Tumors With Predominant Extracranial Extension: Microsurgical Anatomy and Case Series (SevEN-012).

BACKGROUND AND OBJECTIVES: The anterolateral approach (ALA) enables access to the mid and lower clivus, jugular foramen (JF), craniocervical junction, and cervical spine with added anterior and lateral exposure than the extreme lateral and endoscopic endonasal approach, respectively. We describe the microsurgical anatomy of ALA with cadaveric specimens and report our clinical experience for benign JF tumors with predominant extracranial extension. METHODS: A stepwise and detailed microsurgical neurovascular anatomy of ALA was explored with cadaveric specimens. Then, the clinical results of 7 consecutive patients who underwent ALA for benign JF tumors with predominant extracranial extension were analyzed. RESULTS: A hockey stick skin incision is made along the superior nuchal line to the anterior edge of the sternocleidomastoid muscle (SCM). ALA involves layer-by-layer muscle dissection of SCM, splenius capitis, digastric, longissimus capitis, and superior oblique muscles. The accessory nerve runs beneath SCM and is found at the posterior edge of the digastric muscle. The internal jugular vein (IJV) is lateral to and at the level of the accessory nerve. The occipital artery passes over the longissimus capitis muscle and IJV and into the external carotid artery, which is lateral and superficial to IJV. The internal carotid artery (ICA) is more medial and deeper than external carotid artery and is in the carotid sheath with the vagus nerve and IJV. The hypoglossal and vagus nerves run along the lateral and medial side of ICA, respectively. Prehigh cervical carotid, prejugular, and retrojugular surgical corridors allow deep and extracranial access around JF. In the case series, gross and near-total resections were achieved in 6 (85.7%) patients without newly developed cranial nerve deficits. CONCLUSION: ALA is a traditional and invaluable neurosurgical approach for benign JF tumors with predominant extracranial extension. The anatomic knowledge of ALA increases competency in adding anterior and lateral exposure of extracranial JF.

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.

Anatomical variations in the relationship between the spinal accessory nerve and internal jugular vein: a systematic review and meta-analysis.

The relationship between the spinal accessory nerve and internal jugular vein is important for modified neck dissection surgery. Therefore, the aim of this review was to investigate variations in this relationship. Through a search of the PubMed, Scopus, Web of Science, LILACS, and SciELO databases, the review authors collected anatomical data for inclusion in a meta-analysis, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Four relationship patterns were identified and classified: type 1, the nerve lies superficial to the vein; type 2, the nerve lies deep to the vein; type 3, the nerve crosses the branches of the vein; type 4, the nerve splits and its branches pass around the vein. The last pattern was not included in the meta-analysis. Eighteen studies were included (useful sample of 1491 hemi-necks). Type 1 variation had a prevalence of 79.7% (95% CI 77.6-81.7%), type 2 had a prevalence of 19.6% (95% CI 17.7-21.7%), and the type 3 had a prevalence of 0.7% (95% CI 0.0-1.4%). Significant differences were found among geographical subgroups. Normally, the spinal accessory nerve passes superficial to the internal jugular vein, but anatomical variations are common and there is a geographical influence. These findings are important for the safety of modified radical neck dissections.

Outcomes of Spinal Accessory Nerve and Intercostal Nerve Transfers for Shoulder Stabilisation and Elbow Extension in Patients with C5,6,7 Root Avulsion Injury.

Background: Upper arm type brachial plexus palsy results in decreased shoulder and elbow function. Reanimation of shoulder and elbow function is beneficial in these patients. The aim of this study is to report the results of restoring the shoulder abduction and elbow extension in patients with C5,6,7 root avulsion injury by simultaneous transfer of the spinal accessory nerve for the supraspinatus muscle combined with the transferring of the sixth and seventh intercostal nerves for the serratus anterior muscle along with the third to fifth intercostal nerves to the triceps muscle. Methods: All patients who underwent the above set of nerve transfers and had at least 2 years of follow-up were included in the study. The outcome measures included the Medical Research Council (MRC) grading of motor strength of shoulder abduction and elbow extension and range of motion of shoulder abduction and shoulder external rotation. Results: The study included 10 patients with an average age of 27. The mean time from injury to surgery was 6 months and the mean follow-up period was 35 months. M4 grade shoulder abduction was restored in five patients, M3 grade in three patients and M2 grade in two. M4 grade elbow extension was achieved in four patients, M3 grade in four patients and M2 grade in two patients. The average arc of shoulder abduction and external rotation was 71° and -21°, respectively. Conclusions: The spinal accessory nerve and the sixth and seventh intercostal nerves transfer to the supraspinatus muscle and serratus anterior muscle with the third to fifth intercostal nerves transfer to the triceps muscle provided satisfactory results for both shoulder abduction and elbow extension in C5,6,7 root avulsion injury. Level of Evidence: Level IV (Therapeutic).

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.

Functional outcome predictors after spinal accessory nerve to suprascapular nerve transfer for restoration of shoulder abduction in traumatic brachial plexus injuries in adults: the effect of time from injury to surgery.

BACKGROUND: Shoulder abduction is crucial for daily activities, and its restoration is one of the surgical priorities. We evaluated the predictive factors of shoulder abduction functional outcome after spinal accessory nerve (SAN) to suprascapular nerve (SSN) transfer, with special emphasis on the effect of time from injury to the surgery, in the treatment of traumatic brachial plexus injuries. METHOD: This cohort included adult patients who underwent SAN-to-SSN transfer with a preoperative Medical Research Council strength grade 0 and a follow-up of minimum 18 months. The primary outcome was shoulder abduction function (bad, < 30°; good, 30°-60°; or excellent, > 60°). Demographics, trauma characteristics, time lapse between injury and surgery, concomitant axillary nerve reconstruction, and surgery duration were registered. Ordinal logistic regression was used to identify predictors of functional outcomes. RESULTS: The records of 83 patients (86.7% men, mean age 28.8 ± 9.8 years) were analysed. Mean body mass index was 24.1 ± 3.7 kg/m2, and 43.1% were overweight/obese. Motorcycle crashes were the most common trauma mechanism (88.0%). Excellent, good, and bad outcomes were achieved by 20.4%, 38.6%, and 41.0%, respectively. Older patients tended to have worse outcomes (p = 0.074), as well as left-sided lesions (p = 0.015) or those contralateral to manual dominance (p = 0.057). The longer the interval between injury and surgery the worse the outcome: excellent, 5.5 (4.3-7.1); good, 6.9 (5.9-8.7); and bad, 8.2 (5.7-10.1) months (p = 0.018). After multivariable analysis, longer time interval predicted lower odds of better outcomes (OR 0.823, 95% CI 0.699-0.970, p = 0.020; 17.7% lower odds of good or excellent outcome for each additional month). The odd of good or excellent outcomes was also associated with axillary nerve reconstruction (OR 2.767, 95% CI 1.016-7.536, p = 0.046), but not with age or lesion laterality. CONCLUSIONS: Excellent or good functional outcomes for shoulder abduction were achieved by almost sixty percent of adults who underwent SAN-to-SSN transfer for reconstruction of traumatic brachial plexus injuries, associated or not with axillary nerve reconstruction strategies. Longer delays from injury to surgery predicted worse outcomes, and the best time frame seemed to be less than 6 months.

Rare anatomical variant of the spinal accessory nerve: case report and comprehensive review.

Historical studies of the anatomy of the spinal accessory nerve (SAN) have reported conflicting results regarding its relationship with the internal jugular vein (IJV). A literature review was undertaken to establish the prevalence of anatomical variations of the SAN encountered during routine neck dissection surgery, in order to increase awareness and reduce morbidity associated with iatrogenic SAN injury. The published literature was analysed by qualitative synthesis and nine articles were yielded following application of the inclusion and exclusion criteria. Incidences of the SAN lateral to the IJV and medial to the IJV ranged from 39.8% to 96.6%, and 2.6% to 57.4%, respectively. Five of the studies reported incidences of the SAN traversing the IJV, which occurred in 0.9% to 2.8% of cases. One study reported an isolated variant of the SAN dividing around the IJV, with a prevalence of 0.5%. We present a case report demonstrating the rare variant of the SAN traversing the IJV. Preoperative identification of rare anatomical association of the SAN and IJV may reduce perioperative injury to vital structures during neck dissection.

Pathological findings identified during the posterior approach to the spinal accessory nerve after high-energy trauma.

The spinal accessory to suprascapular nerve transfer is a key procedure for restoring shoulder function in upper brachial plexus injuries and is typically undertaken via an anterior approach. The anterior approach may miss injury to the suprascapular nerve about the suprascapular notch, which may explain why functional outcomes are often limited. In 2014 we adopted a posterior approach to enable better visualization of the suprascapular nerve at the notch. Over the next 6 years we have used this approach for 20 explorations after high-energy trauma. In 7/20 we identified abnormalities at the level of the suprascapular ligament, which we would not have identified with an anterior approach: there were two ruptures, two neuromas-in-continuity and three cases of scar encasement, necessitating neurolysis. Nerve transfer could be undertaken distal to the suprascapular notch, bypassing the site of injury. These pathological findings support the wider adoption of the posterior approach in cases of high-energy trauma.Level of evidence: IV.

Shoulder abduction reconstruction for C5-7 avulsion brachial plexus injury by dual nerve transfers: spinal accessory to suprascapular nerve and partial median or ulnar to axillary nerve.

Results of shoulder abduction reconstruction in partial upper-type brachial plexus avulsion injuries are better when a triceps nerve is transferred to the axillary nerve in addition to the spinal accessory to suprascapular nerve transfer. However, in C5-7 avulsion injuries, the triceps nerve may be unavailable as a donor nerve. We report the results of an alternative neurotization to the axillary nerve using either a partial median or ulnar nerve. Patients with C5, 6 ± 7 avulsion injuries and weak triceps who underwent dual nerve transfers for shoulder abduction reconstruction were recruited for the study. The second neurotization to the axillary nerve was from either a partial median or ulnar nerve that had an expandable muscle innervation of ≥ M4 motor power. Patients were assessed for recovery of shoulder abduction and external rotation. Nine patients (median age = 23 years) underwent these dual neurotizations from March 2005 to April 2013. The median time to surgery was 4.5 months. Recovery of shoulder abduction averaged 114.4° (range 90°-180°) and external rotation averaged 136.3° (range 135°-140°). Final shoulder abduction power was > M3 in all 9 patients and ≥ M4 in 6 patients. One patient with partial median nerve transfer had transient hypoaesthesia in his thumb and index finger and another had a residual M4 power in his thumb and index finger flexors. In C5-7 avulsion injuries, dual nerve transfers of the spinal accessory to suprascapular nerve and partial median or ulnar nerve to axillary nerve are good options for shoulder abduction reconstruction with minimal morbidity. Level of evidence is level IV.

Nerve Transfers After Cervical Spine Surgery: Multi-Institutional Case Series and Review of the Literature.

BACKGROUND: Up to 10% of cervical spine surgeries are complicated by postoperative weakness. Although many patients recover with nonoperative management, some require surgery for restoration of function. OBJECTIVE: To present the indications and outcomes of patients undergoing nerve transfers after developing weakness secondary to cervical spine decompression. METHODS: A retrospective review of patients from 2 academic medical centers who underwent nerve transfer for C5-6 root injury after cervical spine surgery was performed. RESULTS: Of the 10 treated patients, 9 experienced recovery at last follow-up, demonstrating improvements in strength and motion in the affected muscles. Successful nerve transfers occurred between 3 and 8 months after the index spinal surgery and included spinal accessory nerve to suprascapular nerve, triceps branch to anterior division of the axillary nerve, and/or ulnar or median fascicles to motor branches of the musculocutaneous nerve. The unsuccessful patient underwent nerve transfer surgery approximately 11 months after the index operation and failed to obtain functional recovery. CONCLUSIONS: Patients who experience C5-6 weakness after cervical spine surgery should be evaluated and considered for nerve transfer surgery if they have continued severe functional deficits at 6 months postoperatively. Earlier referral for nerve transfer is associated with improved functional outcomes in this cohort.

Scapular Winging Secondary to Iatrogenic Spinal Accessory Nerve Lesions.

Motor innervation of trapezius and sternocleidomastoid (SCM) muscles is provided solely by the spinal accessory nerve (SAN). SAN palsy most often occurs as a result of iatrogenic injury to the nerve. A patient, who had undergone neck dissection for thyroid cancer, presented with pain and reduced range of motion of the shoulders. Electroneuromyography revealed denervation of the trapezii and SCM muscles secondary to SAN injury. The patient was treated with a course of physical therapy (PT). This case reminds us that a SAN lesion should be considered in the differential diagnosis of a patient presenting with shoulder pain following surgery of the neck. Even though unilateral SAN injury can eventually lead to atrophy of the trapezius, muscle asymmetry may not be obvious, especially in bilateral iatrogenic SAN injuries. In our experience, these patients benefit from PT. However, evidence to support the use of PT in the treatment of shoulder dysfunction secondary to SAN injury is insufficient; the optimum type and timing of PT requires further investigation. Development of best-practice guidelines in terms of management is necessary. Key Words: Spinal accessory nerve, Electroneuromyography, Scapular winging.

The X-pointer: A forgotten anatomical relationship of spinal accessory nerve and great auricular nerve.

INTRODUCTION: The preservation of the spinal accessory nerve cannot be overlooked in neck dissection. Injury to the nerve results in shoulder dysfunction and other related morbidities. In this article, we describe a unique constant relationship between spinal accessory nerve and great auricular nerve, at the junction of the anterior and posterior triangles of the neck, eponymously labelled the X- pointer. METHODOLOGY: This was an observational study conducted at a tertiary care cancer centre that runs a comprehensive surgical training program. A 100 cases of modified radical neck dissection performed for oral cavity squamous cell carcinoma from January 2017 to January 2019 in were included. The relationship was analyzed in 100 cases of neck dissection for its constancy. RESULT: In all the 100 cases, the X-pointer was demonstrated as a constant anatomical relationship between the spinal accessory nerve and great auricular nerve. The crossing over of the nerve on the undersurface of the sternocleidomastoid muscle is constant and independent of the patient's body proportions. CONCLUSIONS: The relationship between the spinal accessory nerve and great auricular nerve remains constant irrespective of the technique of neck dissection and body habitus of the patient. In our view, this relationship can be used as an additional confirmatory landmark to prevent inadvertent injury to the spinal accessory nerve.

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.

Anatomical aspects of the selective infraspinatus muscle neurotization by spinal accessory nerve.

The suprascapular nerve (SSN) is commonly reconstructed by spinal accessory nerve (SAN) transfer. However, reinnervation of its branch to the infraspinatus muscle (IB-SSN) is poor. Reconstruction of the SSN in cases of scapular fractures is frequently neglected in clinical practice. The morphological study was performed on 25 adult human cadavers. The course and the length of SSN of minimal diameter of 2 mm within the trapezius muscle, the length of the distal stump of IB-SSN to its branching point and the length of the SSN available for reconstructive procedure were measured. The feasibility study of the SAN - IB-SSN neurotization performed by using a bony canal under the spine of scapula was performed. The mean distance of the SAN from the spine was 8.5 cm (±0.88) at the point where it perforates the trapezius muscle and 4.49 cm (±0.72) at the most distal part of the nerve. The mean length of the intramuscular portion of the nerve was 14.74 cm (±1.99). It ran under a mean latero-medial angle of 15.54° (±2.51). The mean distance between the medial end of the scapular spine and the SAN was 2.44 cm (± 0.64). The mean length of the IB-SSN was 3.6 cm (± 0.67). The mean length of the SAN stump which was mobilized from its original course and transferred to the infraspinous fossa to reach distal stump of the IB-SSN was 8.09 cm (±1.6). Direct SAN to IB-SSN transfer is anatomically feasible in the adult population.

The prevalence of nerve injuries following neck dissections - a systematic review and meta-analysis.

INTRODUCTION: Symptoms of the shoulder syndrome (SS) and spinal accessory nerve (SAN) impairments are well-known complications to any neck dissections (NDs). Even so, their prevalence is reported with large variations in the literature. Furthermore, marginal mandibular nerve (MMN) injuries are claimed to be underreported. The purpose of this study was to investigate the prevalence of SS, SAN and MMN injuries after different types of ND. METHODS: This systematic review and meta-analysis included studies reporting SAN and MMN injuries following the three main types of ND. Pooled estimates of the prevalence were made by the main types of ND with 95% confidence intervals (95% CI). RESULTS: Nineteen studies reported a total of 457 SAN injuries. The estimated prevalence of SS or SAN injuries following radical neck dissection, modified radical neck dissection and selective neck dissection was 94.8% (95% CI: 88.5-98.9%), 33.0% (95% CI: 19.4-48.3%) and 27.9% (95% CI: 7.1-54.5%), respectively. Five studies reported a total of 64 MMN injuries. The estimated prevalence following modified radical neck dissection and selective neck dissection was 13.1% (95% CI: 0-37.6%) and 12.7% (95% CI: 4.3-24.1%), respectively. CONCLUSIONS: This meta-analysis estimated a high prevalence of SS, SAN and MMN injuries following the three main types of ND. If oncological considerations allow it, the less morbid ND should be considered. MMN injuries have only been reported in a limited number of small studies. The results may be used to compare future research and as guidance for quality evaluation within departments.