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Folia Morphologica 2023The course of the spinal accessory nerve in the neck is long and superficial rendering it at high risk of injury during procedures performed in the posterior triangle....
BACKGROUND
The course of the spinal accessory nerve in the neck is long and superficial rendering it at high risk of injury during procedures performed in the posterior triangle. The majority of spinal accessory nerve injuries are iatrogenic in nature. This is associated with significant morbidity including reduction in shoulder movements, drooping of the shoulder, winging of the scapula and neuropathic pain. Knowledge of the nerve anatomy reduces the risk of intra-operative nerve injury. Traditional teaching describes the point of entry into the posterior triangle as the intersection between the upper and middle third of the posterior border of sternocleidomastoid. The aim of this study was to determine whether this is in fact the case and if so, whether this landmark can reliably be used to identify the spinal accessory nerve in order to improve patient outcomes.
MATERIALS AND METHODS
The spinal accessory nerve was identified unilaterally in 26 cadavers. The total length of sternocleidomastoid was measured as well as the length along the posterior border from the inferior aspect of the mastoid process to the point at which the accessory nerve enters the posterior triangle of the neck. These measurements were used to calculate the ratio of the entry point of the nerve into the posterior triangle along the length of the posterior border of sternocleidomastoid from its superior insertion point. The mean ratio was 0.35 with 95% confidence intervals of 0.33 to 0.36.
RESULTS AND CONCLUSIONS
Our findings confirm the traditional description of the entry point of the spinal accessory nerve into the posterior triangle of the neck. We describe a so-called 'safe zone' inferior to the midpoint of the posterior border of sternocleidomastoid within which the spinal accessory nerve is unlikely to be found, thereby reducing the risk of iatrogenic injury.
Topics: Humans; Accessory Nerve; Neck; Neck Muscles; Accessory Nerve Injuries; Iatrogenic Disease
PubMed: 35187635
DOI: 10.5603/FM.a2022.0014 -
Insights Into Imaging Oct 2022Peripheral nerves of the upper limb may become entrapped at various points during their anatomical course. While physical examination and nerve conduction studies are... (Review)
Review
Peripheral nerves of the upper limb may become entrapped at various points during their anatomical course. While physical examination and nerve conduction studies are the mainstay of diagnosis, there are multiple imaging options, specifically ultrasound and magnetic resonance imaging (MRI), which offer important information about the potential cause and location of nerve entrapment that can help guide management. This article overviews the anatomical course of various upper limb nerves, including the long thoracic, spinal accessory, axillary, suprascapular, radial, median, ulnar, and musculocutaneous nerves, and describes the common locations and causes of entrapments for each of the nerves. Common ultrasound and MRI findings of nerve entrapments, direct or indirect, are described, and various examples of the more commonly observed cases of upper limb nerve entrapments are provided.
PubMed: 36224295
DOI: 10.1186/s13244-022-01305-5 -
Cardiac Electrophysiology Clinics Sep 2020Supraventricular arrhythmias are the most common cardiac arrhythmias encountered; however, it is uncommon that supraventricular tachycardias require percutaneous... (Review)
Review
Supraventricular arrhythmias are the most common cardiac arrhythmias encountered; however, it is uncommon that supraventricular tachycardias require percutaneous epicardial access for successful mapping and ablation. There are particular scenarios where epicardial access and ablation should be considered. Certain accessory pathways particularly in the posteroseptal region may require epicardial access for successful ablation. These pathways may also be approached from within the coronary sinus system. In addition, tachycardias near the phrenic nerve in the right atrium or left atrium may require epicardial access for successful ablation or to allow displacement of the phrenic nerve facilitating safe catheter ablation.
Topics: Catheter Ablation; Epicardial Mapping; Humans; Pericardium; Tachycardia, Supraventricular
PubMed: 32771189
DOI: 10.1016/j.ccep.2020.05.001 -
Clinical Anatomy (New York, N.Y.) Mar 2021Iatrogenic nerve injury during surgery is a major source of concern for both patients and surgeons. This study aimed to identify the nerves most commonly injured during... (Review)
Review
Iatrogenic nerve injury during surgery is a major source of concern for both patients and surgeons. This study aimed to identify the nerves most commonly injured during surgery, along with the commonly associated operative procedures. A literature search was conducted using the PubMed database to identify nerves commonly injured during surgery, along with the surgical procedure associated with the injury. The following 11 nerves, ranked in order with their associated surgical procedures, were found to be the most commonly injured: (a) intercostobrachial nerve in axillary lymph node dissections and transaxillary breast augmentations, (b) vestibulocochlear nerve in cerebellopontine tumor resections and vestibular schwannoma removals, c) facial nerve in surgeries of the inner ear and cheek region, (d) long thoracic nerve in axillary lymph node dissections, (e) spinal accessory nerve in surgeries of the posterior triangle of the neck and cervical lymph node biopsies, (f) recurrent laryngeal nerve in thyroid surgeries, (g) genitofemoral nerve in inguinal hernia and varicocele surgeries, (h) sciatic nerve in acetabular fracture repairs and osteotomies, (i) median nerve in carpal tunnel release surgeries, (j) common fibular nerve in varicose vein and short saphenous vein surgeries, and (k) ulnar nerve in supracondylar fracture surgeries. Although the root cause of iatrogenic nerve injury differs for each nerve, there are four unifying factors that could potentially decrease this risk for all peripheral nerves. These four influencing factors include knowledge of potential anatomical variations, visual identification of at-risk nerves during the procedure, intraoperative nerve monitoring, and expertise of the surgeon.
Topics: Humans; Iatrogenic Disease; Peripheral Nerve Injuries; Surgical Procedures, Operative
PubMed: 33090551
DOI: 10.1002/ca.23696 -
Life (Basel, Switzerland) Sep 2023To restore elbow flexor muscle function in case of traumatic brachial plexus avulsion, the phrenic nerve transfer to the musculocutaneous nerve has become part of...
BACKGROUND
To restore elbow flexor muscle function in case of traumatic brachial plexus avulsion, the phrenic nerve transfer to the musculocutaneous nerve has become part of clinical practice. The nerve transfer can be done by means of video-assisted thoracic surgery without nerve graft or via supraclavicular approach in combination with an autograft. This study focuses on a detailed microscopic and macroscopic examination of the phrenic nerve. It will allow a better interpretation of existing clinical results and, thus, serve as a basis for future clinical studies.
MATERIAL AND METHODS
An anatomical study was conducted on 28 body donors of Caucasian origin (female n = 14, male n = 14). A sliding caliper and measuring tape were used to measure the diameter and length of the nerves. Sudan black staining was performed on 15 µm thick cryostat sections mounted on glass slides and the number of axons was determined by the ImageJ counting tool. In 23 individuals, the phrenic nerve could be examined on both sides. In 5 individuals, however, only one side was examined. Thus, a total of 51 nerves were examined.
RESULTS
The mean length of the left phrenic nerves (33 cm (29-38 cm)) was significantly longer compared to the mean length of the right phrenic nerves (30 cm (24-33 cm)) ( < 0.001). Accessory phrenic nerves were present in 9 of 51 (18%) phrenic nerves. The mean number of phrenic nerves axons at the level of the first intercostal space in body donors with a right accessory phrenic nerve was significantly greater compared to the mean number of phrenic nerves axons at the same level in body donors without a right accessory phrenic nerve (3145 (range, 2688-3877) vs. 2278 (range, 1558-3276)), = 0.034. A negative correlation was registered between age and the nerve number of axons in left (0.742, < 0.001) and right (-0.273, = 0.197) phrenic nerves. The mean distance from the upper edge of the ventral ramus of the fourth cervical spinal nerve to the point of entrance of the musculocutaneous nerve between the two parts of the coracobrachialis muscle was 19 cm (range, 15-24 cm) for the right and 20 cm (range, 15-25 cm) for the left arm.
CONCLUSIONS
If an accessory phrenic nerve is available, it presumably should be spared. Thus, in that case, a supraclavicular approach in combination with a nerve graft would probably be of advantage.
PubMed: 37763296
DOI: 10.3390/life13091892 -
Hand Surgery & Rehabilitation Feb 2022Scapula alata, also known as winged scapula, can lead to severe upper limb impairment. The shoulders' function is altered because the scapula, which supports the upper...
Scapula alata, also known as winged scapula, can lead to severe upper limb impairment. The shoulders' function is altered because the scapula, which supports the upper limb, is no longer stable. Typical scapula alata is described for serratus anterior palsy; however, any scapulothoracic muscle impairment may lead to scapular winging, particularly trapezius palsy, which is easy to miss, thus needed to be considered as a differential diagnosis. The diagnosis is difficult and based on various clinical tests and a thorough examination as well as electroneuromyography and MRI. The treatment ranges from conservative treatments for spontaneous recovery, nerve surgery including neurolysis, nerve transfers and nerve grafts for acute cases, to tendon transfers for more chronic cases and when nerve procedures are no longer feasible. Tendon transfers in serratus anterior palsy produce excellent results with a high rate of patient satisfaction and are described with the sternal or clavicular head of the pectoralis major; we describe our preferred technique in this article. Tendon transfers in trapezius palsy are performed with the levator scapulae, rhomboid minor and major muscles. Our preferred method is the Elhassan triple transfer. Scapula alata is a frequent and often misdiagnosed condition. Appropriate management can yield excellent results. Patients should be referred right away to specialized centers for surgery if recovery is not spontaneous.
Topics: Humans; Range of Motion, Articular; Scapula; Superficial Back Muscles; Tendon Transfer; Thoracic Nerves
PubMed: 34246815
DOI: 10.1016/j.hansur.2020.09.016 -
Arthroscopy : the Journal of... Feb 2023The optimal nerve block to help reduce pain after hip arthroscopy is undetermined. The fascia iliaca block was en vogue but may result in weakness, neuropathy, and...
The optimal nerve block to help reduce pain after hip arthroscopy is undetermined. The fascia iliaca block was en vogue but may result in weakness, neuropathy, and equivocal pain outcomes. Other options include blocks to the femoral nerve, the lumbar plexus, the quadratus lumborum, and, more recently, the pericapsular nerve group block (PENG), in which ultrasound guidance allows injection under the iliopsoas muscle to affect the accessory obturator nerve and the articular branches of the femoral nerve. PENG block should not result in weakness, but weakness has been reported after PENG block for total hip arthroplasty, and falls could be a risk and a concern. The arthroplasty literature also suggests the PENG block adds little benefit to intra-articular injection beyond the recovery room and is comparable with a fascia iliac block. Perhaps the PENG block could show benefit in select cases such as for severe postoperative pain or in patients with anticipated pain control challenges. Until an ideal block for hip arthroscopy is determined, a patient tailored approach is indicated.
Topics: Humans; Arthroscopy; Nerve Block; Pain Management; Pain, Postoperative; Arthroplasty, Replacement, Hip; Femoral Nerve
PubMed: 36603998
DOI: 10.1016/j.arthro.2022.10.021 -
AJNR. American Journal of Neuroradiology Sep 2023Benign enhancing foramen magnum lesions have been previously described as T2-hyperintense small, enhancing lesions located posterior to the intradural vertebral artery....
Benign enhancing foramen magnum lesions have been previously described as T2-hyperintense small, enhancing lesions located posterior to the intradural vertebral artery. We present the first case with pathologic correlation. These lesions are fibrotic nodules adhering to the spinal accessory nerve. While they can enlarge with time on subsequent examinations, on the basis of the imaging characteristics and location, they do not necessitate surgical resection.
Topics: Humans; Foramen Magnum; Vertebral Artery
PubMed: 37536735
DOI: 10.3174/ajnr.A7955 -
Muscle & Nerve May 2020Various techniques are described for proximal motor nerve conduction studies (NCSs). We investigated alternative reference electrode (E2) locations for accessory and...
BACKGROUND
Various techniques are described for proximal motor nerve conduction studies (NCSs). We investigated alternative reference electrode (E2) locations for accessory and axillary NCSs.
METHODS
Multi-channel recordings were made from trapezius or deltoid referred to different sites, and from those sites referred to a remote electrode. Responses were compared using grouped statistics, and correlation analysis.
RESULTS
For accessory NCSs, all belly:E2 montages showed comparable responses but axillary NCSs were more variable. Low amplitude contamination was seen at the sternum and contralateral acromion but greater distortion using other potential E2 sites. In both accessory and axillary studies, the ipsilateral acromion showed moderate activity, which correlated with the belly:remote response.
CONCLUSIONS
Variation in E2 electrode sites may significantly distort the measured compound muscle action potential (CMAP). For accessory and axillary NCS, a sternal reference has favorable characteristics. Other sites, such as ipsilateral acromion or deltoid insertion, may not yield a representative CMAP.
Topics: Accessory Nerve; Acromion; Action Potentials; Adult; Aged; Aged, 80 and over; Anatomic Landmarks; Axilla; Brachial Plexus; Deltoid Muscle; Elbow; Electrodes; Electrodiagnosis; Female; Hand; Humans; Male; Middle Aged; Neural Conduction; Sternum; Superficial Back Muscles; Young Adult
PubMed: 32108362
DOI: 10.1002/mus.26847 -
PM & R : the Journal of Injury,... Jun 2020Various active recording electrode positions for the trapezius motor nerve conduction study have been suggested.
BACKGROUND
Various active recording electrode positions for the trapezius motor nerve conduction study have been suggested.
OBJECTIVE
To determine the optimal recording site of the trapezius muscles in a spinal accessory nerve conduction study.
DESIGN
Retrospective descriptive study.
SETTING
Department of physical medicine and rehabilitation in a tertiary clinic center.
PARTICIPANTS
Thirty-four patients between 33 and 82 years of age with preoperative head and neck cancer (68 upper and middle trapezius muscles).
INTERVENTIONS
Analysis of compound muscle action potentials (CMAPs) of upper and middle trapezius.
MAIN OUTCOME MEASUREMENTS
CMAP latency and amplitudes were obtained at five and four recording points with constant intervals on the horizontal line of the upper and middle trapezius, respectively.
RESULTS
The maximum CMAP amplitude of the upper trapezius was (mean ± SD) 8.5 ± 1.4 mV with the recording at the midpoint between the C7 spinous process and the lateral margin of the acromion. The maximum CMAP amplitude of the middle trapezius was 4.2 ± 1.4 mV, recorded on the horizontal line at the junction of the middle and lateral thirds between the root of the scapular spine and the vertebral spinous process.
CONCLUSION
The optimal recording site in motor nerve conduction study of the trapezius is the midpoint between the C7 spinous process and the acromion for the upper trapezius, and the junction of middle and lateral thirds of the line between the root of scapular spine and the vertebral spine for the middle trapezius.
Topics: Adult; Aged; Aged, 80 and over; Electrodes; Electromyography; Head and Neck Neoplasms; Humans; Middle Aged; Rehabilitation Centers; Retrospective Studies; Spine; Superficial Back Muscles; Tertiary Care Centers
PubMed: 31677234
DOI: 10.1002/pmrj.12278