Selective denervation of the levator scapulae muscle: an amendment to the Bertrand procedure for the treatment of spasmodic torticollis

OBJECT: The purpose of this cadaveric study was to explore a modification to the Bertrand procedure for the treatment of spasmodic torticollis, namely the denervation of the levator scapulae (LS) muscle for laterocollis. METHODS: The authors performed a series of 9 cadaveric dissections. Five were done to identify the anterior innervation of the LS, and the remaining 4 were to identify the tendinous insertions of the LS onto the lateral masses of the cervical spine via a posterior approach. The nerve supply to the LS from the anterior divisions of the C-3 and C-4 nerve roots and the contribution from the dorsal scapular nerve were identified over the anterior surface of the muscle. RESULTS: The C-3 and C-4 nerve root branches were situated within 2 cm of each other and inferior to the punctum nervosum. The dorsal scapular contribution was clearly identified in 2 cadavers. Selective denervation of this muscle is possible through the same posterior triangle incision used for denervating the sternocleidomastoid muscle of its accessory nerve branches. This approach will be helpful in patients with laterocollis contralateral to the direction of chin turning. The authors compare this approach to the posterior approach for sectioning the insertions of the LS muscle onto the C1-4 posterior tubercles. The latter approach is appropriate for ipsilateral laterocollis. CONCLUSIONS: The posterior triangle approach for denervating the LS muscle is a safe and easy addition to the Bertrand procedure and can be helpful in selected cases of torticollis with a laterocollis component.     

Surgical anatomy of the dorsal scapular nerve

OBJECT: There is a paucity of literature regarding the surgical anatomy of the dorsal scapular nerve (DSN). The aim of this study was to elucidate the relationship of this nerve to surrounding anatomical structures. METHODS: Ten formalin-fixed human cadavers (20 sides) were dissected, and measurements made between the DSN and related structures. The nerve pierced the middle scalene muscle at a mean distance of 3 cm from its origin from the cervical spine and was more or less centrally located at this exit site. It lay a mean distance of 1.5 cm medial to the vertebral border of the scapula between the serratus posterior superior, posterior scalene, and levator scapulae muscles. It was found to have a mean distance of 2.5 cm medial to the spinal accessory nerve as it traveled on the anterior border of the trapezius muscle. The nerve intertwined the dorsal scapular artery in all specimens and was found along the anterior border of the rhomboid muscles. On 19 sides the DSN originated solely from the C-5 spinal nerve, and on one side it arose from the C-5 and C-6 spinal nerves. CONCLUSIONS: Knowledge of the anatomy of the DSN will aid the surgeon who wishes to explore and decompress this structure.     

Selective blockade of the dorsal scapular nerve for scapula surgery

The dorsal scapular nerve, a proximal branch of the brachial plexus, may be imaged using ultrasound. This nerve supplies the rhomboid and levator scapulae muscles while providing significant sensory innervation to the scapula. An ultrasound-guided nerve block of the dorsal scapular nerve provided analgesia after surgery of the scapula. Selective blockade of this nerve, without blocking the remainder of the brachial plexus, results in specific analgesia of the scapula, sparing sensory and motor function of the ipsilateral arm.     

The 2 key muscles in thoracotomy for excision of the lung. The latissimus dorsi and the levator scapulae muscles

Anatomical data related to the thoracotomies performed most frequently in lung surgery are described in some detail: continuity between serratus anterior and levator scapulae as a vide muscular sheet possessing a common deep aponeurosis (thoracolumbar fascia) extending Gilis' space to the vertebral column as the levator scapulae-thoraci space; presence of a "composite aponeurosis" in the posterior angle between serratus anterior and levator scapulae, covering the 8th rib triangle or triangle of auscultation; long costal insertion area and presence of two differently orientated muscle layers for the digitations, particularly of apical bundle. Supplied by a rich vascularization of multiple sources, the serratus anterior and latissimus dorsi are two muscles with single longitudinal nerve pedicles derived from brachial plexus. It is certainly the denervation which is responsible for the distal atrophy of these muscles "sectioned on the right of the selected ribs" following conventional thoracotomy. To avoid esthetic and functional sequelae this innervation must be preserved as far as possible by: interrupting division of serratus anterior anterior to long thoracic nerve and avoiding inclusion of axillary border of latissimus dorsi during lateral thoracotomy; sectioning the latissimus dorsi as low as possible--the other muscles being simply freed and inclined--during lateral thoracotomy.     

Vulnerability of the spinal accessory nerve in the posterior triangle of the neck: a cadaveric study.

Injury to the accessory nerve results in an obvious shoulder droop, loss of shoulder elevation, and pain. Prevention of inadvertent injury to the accessory nerve is critical in neck dissection. No previous study, however, anatomically demonstrates the mechanism of the spinal accessory nerve traction injury. Anatomic determination of the location and course of the spinal accessory nerve may be helpful for a better understanding of the mechanism of the nerve injury. The accessory nerve courses obliquely across the posterior triangle on the surface of the levator scapula muscle and reaches the trapezius. The length of the spinal accessory nerve in the posterior triangle is 34.7+/- 6.3 mm. The nerve passes through the posterior border of the sternocleidomastoid muscle 50.7+/- 12.9 mm below the tip of the mastoid process and reaches the anterior border of the trapezius 49.8 +/- 5.9 mm above the clavicle. It makes a posterior angle of 73.1 degrees +/- 19.4 degrees, on average, relative to the posterior border of the sternocleidomastoid. When the shoulder is pulled down and the head is turned to the opposite direction, the spinal accessory nerve is stretched in the posterior triangle. In the posterior triangle, the nerve is vulnerable, since it is superficial and covered only by skin and subcutaneous fascia. Therefore, extreme caution should be taken with any surgical procedures in the posterior triangle. Traction injury of the spinal accessory nerve in the posterior triangle cannot be ignored.     

颞下窝咽旁间隙的显微外科解剖研究

目的 研究颞下窝、咽旁间隙的显微外科解剖，探讨该区域的解剖境界及临床意义。方法 选择经10％福尔马林固定成人头颈标本10具，显微镜下模拟耳前颞底，颞下窝入路的手术操作，逐层显露颞下窝和咽旁间隙，研究该区域肌肉、神经血管和骨性结构的相互及定位标志。结果 颞下窝内的主要结构有翼内肌、翼外肌、上颌动脉、翼静脉丛、下颌神经及其分支等。茎突隔膜将咽旁间隙分为茎突前区和茎突后区，颈内动脉、颈内静脉及Ⅸ、Ⅹ、Ⅺ、Ⅻ脑神经等重点结构位于茎突后区内。茎突隔膜由二腹肌后腹、茎突肌群、茎突舌骨韧带和茎突下颌韧带、茎突咽筋膜和由二腹肌延至胸锁乳突肌的筋膜构成。结论 颞下窝为下颌骨和翼内侧板之间的区域，咽旁间隙系颞下窝后方、鼻咽外侧及颈椎腹侧的区域；茎突隔膜包绕颈内动脉，为颞下窝咽旁间隙区域的重要解剖标志。     

The anatomy of the pectoral nerves and their significance in brachial plexus reconstruction

Twenty-nine brachial plexuses from 13 embalmed and 5 fresh cadavers were examined under x3.5 loupe magnification to collect systematic and topographic anatomical data regarding the lateral and medial pectoral nerves. Additionally, nerve biopsy specimens were harvested in 5 fresh cadavers to obtain histomorphometric data. In all dissections the pectoral nerves exited at the trunk level as 3 distinct nerves. The superior pectoral nerve (from the anterior division of the superior trunk) commences just distal to the suprascapular nerve and courses laterally to innervate the lateral clavicular portion of the pectoralis major muscle (PM) with 2 to 4 branches. The middle pectoral nerve (from the anterior division of the middle trunk) courses distally and enters the infraclavicular fossa with 2 constant branches. The superficial branch terminates in the medial clavicular and upper sternal parts of the PM. The deep branch always forms a plexus with the medial pectoral or inferior pectoral nerve (from the anterior division of the inferior trunk), which courses at a right angle around the the lateral thoracic artery. From this plexus several branches terminate in the Pm. The branch to the lower aspect of the PM pierces the pectoralis minor muscle in two thirds of cases, whereas it passes its inferior border to reach the lower aspects of the PM with an average length of 15 cm in one third of cases. Knowledge of the detailed anatomy of the pectoral nerves, as outlined in this study, clarifies the obscure anatomic relationship of the lateral and medial pectoral nerves and allows easy intraoperative location of the medial pectoral nerve at the exit of the lateral thoracic artery. The length of the inferior pectoral nerve, the number of motor axons, and the anatomical proximity of this nerve make it an expendable but powerful source of reinnervation to the musculocutaneous nerve in upper brachial plexus injuries.     

Surgical anatomy of spinal accessory nerve: is trapezius functional deficit inevitable after division of the nerve?

The course of spinal accessory nerve in the posterior triangle, the innervation of the sternocleidomastoid and trapezius muscles and the contributions from the cervical plexus were studied in 20 cadaveric dissections. The nerve was most vulnerable to iatrogenic injuries after leaving the sternocleidomastoid. Direct innervation of trapezius by cervical plexus branches was noted in five dissections, whereas connections between the cervical plexus and the spinal accessory nerve were observed in 19 dissections. These were usually under the sternocleidomastoid (proximal to the level of division of the nerve in nerve transfer procedures). Although the contribution from the cervical plexus to trapezius innervation is considered minimal, trapezius function can be protected in neurotization procedures by transecting the spinal accessory nerve distal to its branches to the upper position of trapezius.     

颈横动脉对臂丛神经影响的应用解剖

目的探索臂丛的周围血管——颈横动脉是否对臂丛神经造成卡压以及解决的方法。方法选用陈旧性成人尸体31具62侧,在胸廓出口部位进行颈横动脉的应用解剖学研究,重点是它与臂丛神经的关系。结果13侧未见颈横浅动脉,49侧中出现51条颈横浅动脉,其中11条与臂丛神经有紧密接触,占21.15%。16侧未见颈横深动脉,46侧有52条颈横深动脉（肩胛背动脉）,其中31条与臂丛神经密切接触,9条在臂丛神经上留下明显压迹,占17.31%。结论颈横动脉,尤其是颈横深动脉（肩胛背动脉）可以形成对臂丛神经的卡压,是又一个可能导致胸廓出口综合征的原因之一。     

Continuous brachial plexus block at the cervical level using a posterior approach in the management of neuropathic cancer pain

BACKGROUND AND OBJECTIVES: Neuropathic cancer pain due to tumor growth near the brachial plexus is often treated with a combination of nonsteroidal anti-inflammatory drugs, tricyclic antidepressants, anticonvulsants, and oral or transdermal opioids. We propose placement of a catheter along the brachial plexus using a posterior approach for patients not responding to the above-mentioned treatment. CASE REPORT: We describe 2 patients with neuropathic cancer pain in the arm and shoulder despite treatment with dexamethasone, amitriptyline, gabapentin, opioids, and, in 1 patient, oral ketamine. An increase in daily opioid dosage did not relieve the pain but caused unacceptable side effects of nausea, vomiting, and sedation. Continuous administration of local anesthetics via a brachial plexus catheter inserted at the cervical level using a posterior approach resulted in a markedly improved analgesia and decreased opioid requirement. CONCLUSION: Continuous brachial plexus block should be considered in patients with severe neuropathic cancer pain in the arm and shoulder. To achieve sufficient pain relief for prolonged periods of time, a catheter was inserted to block the brachial plexus using a posterior approach. This technique may be a valuable alternative to the interscalene approach because of the improved fixation of the catheter in the muscle sheet of the trapezius, splenius cervicus, and levator scapulae muscles, and the decreased likelihood of catheter dislodgment during neck movements.     

颈脊神经后内侧支卡压的解剖及其临床意义

目的为临床诊治颈神经后内侧支卡压提供解剖学基础。方法对10具（20侧）成人尸体头颈标本颈脊神经后内侧支易受卡压的部位进行解剖学观测。结果（1）C2颈脊神经后内侧浅支（枕大神经）易受卡压处分别位于该神经走行于头下斜肌与枢椎椎弓板之间段、穿过头半棘肌段和穿上项线骨纤维孔处。（2）C3-5脊神经后内侧浅支（第三枕神经）易受卡压处分别位于该神经穿行头半棘肌和穿头夹肌段。C3颈脊神经后内侧深支即头夹肌支,该神经穿过头半棘肌处。（3）C3-8后内侧支穿颈脊神经后支骨纤维管。结论颈神经后内侧支穿行的骨纤维管、项部肌肉、项部肌肉的腱性组织是造成颈脊神经后内侧支卡压的解剖学基础。     

Anatomy of the spinal nerves and dermatomes

There are 31 pairs of spinal nerves: eight cervical, 12 thoracic, five lumbar, five sacral and one coccygeal. They form by fusion of a posterior sensory spinal root (bearing its posterior root ganglion) with an anterior motor root. These join at each intervertebral foramen. Typically, the nerve then divides into a posterior and an anterior primary ramus. The former supplies the vertebral muscles and dorsal skin. The anterior primary ramus in the thoracic region bears a white ramus communicans to the sympathetic ganglion. Each spinal nerve receives a grey ramus from the sympathetic chain. The nerves T2–T12 supply the skin and muscles of the trunk sequentially. The other nerves are arranged into the cervical, brachial, lumbar and sacral plexuses. The cervical plexus supplies the skin and anterior muscles of the neck and forms the phrenic nerve (C3–C5), while the brachial plexus supplies the skin and muscles of the upper limb, and the lumbar and sacral plexuses supply the skin of the lower limb and perineum and the muscles of the posterior abdominal wall, pelvis, perineum and lower limb. The segmental nerves are arranged to supply the skin (dermatomes), while the segmental supply to the limb muscles, the myotomes, is more complex.     

臂丛神经的交感神经支配及其临床意义

目的：了解颈交感神经在臂丛神经上的分布并探讨其对臂丛神经活动的影响及引起颈肩痛的机制。方法：对30具60例成人尸体标本，大体和显微镜解剖颈部的交感神经；并对2具4例新鲜成人尸体进行颈部局部封闭。结果：支配臂丛神经的交感社会支主要来自颈下节和颈中节。颈中节到臂丛的分支大部分紧贴或穿过前、中斜角肌，部分穿入椎孔后加入臂丛。颈下节的分支则绕过锁骨下动脉或椎动脉后到达臂丛。局部封闭后发现药物浸润范围主要在颈椎横穿尖部或前侧。结论：颈交感神经到达臂丛神经的分支与颈部软组织的解剖关系密切，软组织活动会影响交感社会对臂丛的支配，并可引起颈肩痛。     

Selective peripheral denervation for spasmodic torticollis involving the levator scapulae muscle

Patients with laterocollis or rotatory type torticollis tend to show abnormal contraction of the levator scapulae muscle and the scalene muscles. These muscles are innervated from the anterior branches of the cervical spinal nerves. Because of this, the traditional Bertrand operation dealing with posterior branches does not adequately affect the symptoms of laterocollis. The authors report selective denervation of the levator scapulae muscle in three patients and discuss its rationale. All the three patients underwent denervation of both the C1-C6 posterior spinal rami and the branches from the C3 and C4 anterior rami to the levator scapulae muscle. We added myotomy of the scalene muscle in one patient, and denervation of the omohyoid muscle which is innervated from the ansa cervicalis and the descending branch of the hypoglossal nerve. The pre/post-operative Tsui scores were 12/4, 15/1, and 14/3 respectively. There were no complications. We conclude that selective peripheral denervation of the levator scapulae muscle is safe and effective in the treatment of laterocollic type torticollis.     

Innervation of the trapezius muscle by the intra-operative measurement of motor action potentials

Although the surgical anatomy of the spinal accessory nerve and the cervical plexus has been extensively described, the exact motor innervation of the trapezius has been controversial. Attempts to resolve this question have involved anatomic or electrophysiologic studies in human embryos and animals. Extrapolation of the results to adult humans may not be correct. Accurate identification of muscle innervation is obtainable by intra-operative measurement of motor action potentials produced by direct stimulation of the accessory nerve and the cervical plexus. The study involved 14 patients undergoing supraomohyoid or modified neck dissections. Under direct vision, stimulating electrodes were placed on the identified nerves and motor action potentials, and latencies were recorded by surface electrodes placed over the three portions of the trapezius. In 13 patients, when the accessory nerve was stimulated, motor action potentials were obtained in 13 of 13 in the first portion, 11 of 13 in the second portion, and 10 of 13 in the third portion of the trapezius. In the last patient, the accessory nerve ended in the sternocleidomastoid muscle, and innervation of the trapezius was via C3 as demonstrated by motor action potentials. Responses when the roots of the cervical plexus were stimulated varied. Three patterns were seen: In the first group (seven patients), motor action potentials were distinct from those recorded when the accessory nerve was stimulated. Additionally, latencies were different from those of the accessory nerve. The second group (four patients) had motor action potentials that were similar to those obtained from stimulation of the accessory nerve, although their corresponding latencies were different. In two patients, no motor action potentials were recorded when the cervical plexus was stimulated. The results suggest that motor innervation of the trapezius is variable. The accessory nerve, when present, provides the most important input to the trapezius. Motor innervation from the cervical plexus is unpredictable, although it appears to be present in the majority of patient studies.     

Failure of supraclavicular block under ultrasound guidance: clinical relevance of anatomical variation of cervical vessels

We describe a case with partial analgesia after ultrasound-guided supraclavicular block for elbow surgery. The failure of the block was caused by the limited spread of local anesthetic because of blockage by a vessel (either transverse cervical artery or dorsal scapular artery) running through the brachial plexus. Anesthesiologists should be aware that cervical anatomy is complex and has anatomical variations. Thus, careful ultrasound screening of anatomical structure, especially using color Doppler, is important in performing brachial plexus block.     

Functional Evaluation of Levator Scapulae Tendon to Supraspinatus in Adult Brachial Plexus Injuries

Introduction  Brachial plexus injuries are severe life-altering injuries. The surgical method to restore shoulder abduction in adult upper brachial plexus injuries involves the usage of nerve grafts and nerve transfers targeting the suprascapular and/or the axillary nerve. When the primary nerve surgery has been unsuccessful or recovery has been incomplete or with a late presentation, muscle transfer procedures are needed to provide or improve shoulder abduction. Levator scapulae to supraspinatus is a transfer to improve shoulder abduction in posttraumatic brachial plexus injuries. Material and Methods  The study included 13 patients with the age ranging from 17 to 47 years with a mean age of 30 years. All these patients had preop shoulder abduction of Medical Research Council (MRC) grade ≤3. All had a minimum of MRC grade 4 of active elbow flexion. Eleven patients had primary surgery. Only patients with a minimum of 1 year postoperative follow-up were included. All 13 patients underwent levator scapulae transfer only. Results  All patients had a stable shoulder postoperatively. The average increase in active shoulder abduction was from 6.15°(median: 0°) preoperatively to 61.92°(median: 60°), with an average gain in shoulder abduction of 49.61°(median: 50°). Conclusions  Transfer of levator scapulae tendon to the supraspinatus is an option to improve shoulder abduction in posttraumatic brachial plexus. In conditions where supraspinatus alone is not functioning, levator scapulae is the best available transfer, considering its strength and maintaining the form of the shoulder unlike trapezius transfer. In patients with previous surgery where supraspinatus has recovered partially but not functionally significant, this tendon transfer can be considered for the augmentation of the existing shoulder abduction.     

Contributions of the fourth spinal nerve to the brachial plexus without prefixation

OBJECT: The intradural contributions of the C-4 nerve rootlets have not been previously evaluated for their connections to the brachial plexus. The authors undertook a cadaveric study to evaluate the C-4 contributions to the upper trunk of the brachial plexus. METHODS: The posterior cervical triangles from 60 adult cadavers were dissected. All specimens that were found to have extradural C-4 contributions to the upper trunk of the brachial plexus were excluded from further study. In specimens found to have no extradural C-4 contributions to the brachial plexus a C1-T1 laminectomy was performed. Observations were made of any neural communications between adjacent spinal rootlets, specifically between C-4 and C-5. RESULTS: Nine (15%) of the 60 sides were found to have extradural C-4 contributions to the upper trunk of the brachial plexus. These sides were excluded from further study. No specimen was found to have a postfixed brachial plexus. Of the remaining 51 sides, 11 (21.6%) were found to have intradural neural connections between C-4 and C-5 dorsal rootlets and 1 (1.96%) had a connection between the ventral roots of C-4 and C-5. Communications between these 2 adjacent dorsal cervical cord levels were of 3 types. Type I was a vertical communication between the more horizontally traveling dorsal roots. Type II was a forked communication between adjacent C-4 and C-5 dorsal rootlets. The Type III designation was applied to connections between ventral rootlets. Although communications were slightly more frequent on left sides, this did not reach statistical significance. CONCLUSIONS: In approximately 20% of normally composed brachial plexuses (those with extradural contributions from only C5-T1) we found intradural C4-5 neural connections. Such variations may lead to misinterpretation of spinal levels in pathological conditions of the spinal axis and should be considered in surgical procedures of this region, such as rhizotomy.