Risk of Encountering Dorsal Scapular and Long Thoracic Nerves during Ultrasound-guided Interscalene Brachial Plexus Block with Nerve Stimulator

BACKGROUND: Recently, ultrasound has been commonly used. Ultrasound-guided interscalene brachial plexus block (IBPB) by posterior approach is more commonly used because anterior approach has been reported to have the risk of phrenic nerve injury. However, posterior approach also has the risk of causing nerve injury because there are risks of encountering dorsal scapular nerve (DSN) and long thoracic nerve (LTN). Therefore, the aim of this study was to evaluate the risk of encountering DSN and LTN during ultrasound-guided IBPB by posterior approach. METHODS: A total of 70 patients who were scheduled for shoulder surgery were enrolled in this study. After deciding insertion site with ultrasound, awake ultrasound-guided IBPB with nerve stimulator by posterior approach was performed. Incidence of muscle twitches (rhomboids, levator scapulae, and serratus anterior muscles) and current intensity immediately before muscle twitches disappeared were recorded. RESULTS: Of the total 70 cases, DSN was encountered in 44 cases (62.8%) and LTN was encountered in 15 cases (21.4%). Both nerves were encountered in 10 cases (14.3%). Neither was encountered in 21 cases (30.4%). The average current measured immediately before the disappearance of muscle twitches was 0.44 mA and 0.50 mA at DSN and LTN, respectively. CONCLUSIONS: Physicians should be cautious on the risk of injury related to the anatomical structures of nerves, including DSN and LTN, during ultrasound-guided IBPB by posterior approach. Nerve stimulator could be another option for a safer intervention. Moreover, if there is a motor response, it is recommended to select another way to secure better safety.

Dynamic Stabilization of the Scapula for Serratus Anterior Dysfunction: A Retrospective Study of Functional Outcome and Results

BACKGROUND: Twenty-six patients (12 male and 14 female) with symptomatic scapular winging caused by serratus anterior dysfunction were managed by split pectoralis major tendon transfer (sternal head) with autogenous hamstring tendon augmentation from 1998 to 2006. METHODS: Twenty-five patients showed positive results upon long thoracic nerve palsy on electromyography. The mean duration of symptoms until surgery was 48 months (range, 12-120 months). Four patients had non-traumatic etiologies and 22 patients had traumatic etiologies. On follow-up assessment for functional improvement, a Constant-Murley score was used. Twenty-one patients were completely evaluated, while five patients who had less than 12 months of follow-up were excluded. RESULTS: Pain relief was achieved in 19 of the 21 patients, with 20 patients showing functional improvement. The pain scores improved from 6.0 preoperatively to 1.8 postoperatively. The mean active forward elevation improved from 108degrees (range, 20degrees-165degrees) preoperatively to 151degrees (range, 125degrees-170degrees) postoperatively. The mean Constant-Murley score improved from 57.7 (range, 21-86) preoperatively to 86.9 (range, 42-98) postoperatively. A recurrence developed in one patient. Of the 21 patients, ten had excellent results, six had good results, four had fair results, and one had poor results. CONCLUSIONS: Most patients with severe symptomatic scapular winging showed functional improvement and pain relief with resolution of scapular winging.

Dynamic Stabilization of the Scapula for Serratus Anterior Dysfunction: A Retrospective Study of Functional Outcome and Results

BACKGROUND: Twenty-six patients (12 male and 14 female) with symptomatic scapular winging caused by serratus anterior dysfunction were managed by split pectoralis major tendon transfer (sternal head) with autogenous hamstring tendon augmentation from 1998 to 2006. METHODS: Twenty-five patients showed positive results upon long thoracic nerve palsy on electromyography. The mean duration of symptoms until surgery was 48 months (range, 12-120 months). Four patients had non-traumatic etiologies and 22 patients had traumatic etiologies. On follow-up assessment for functional improvement, a Constant-Murley score was used. Twenty-one patients were completely evaluated, while five patients who had less than 12 months of follow-up were excluded. RESULTS: Pain relief was achieved in 19 of the 21 patients, with 20 patients showing functional improvement. The pain scores improved from 6.0 preoperatively to 1.8 postoperatively. The mean active forward elevation improved from 108degrees (range, 20degrees-165degrees) preoperatively to 151degrees (range, 125degrees-170degrees) postoperatively. The mean Constant-Murley score improved from 57.7 (range, 21-86) preoperatively to 86.9 (range, 42-98) postoperatively. A recurrence developed in one patient. Of the 21 patients, ten had excellent results, six had good results, four had fair results, and one had poor results. CONCLUSIONS: Most patients with severe symptomatic scapular winging showed functional improvement and pain relief with resolution of scapular winging.

Lesiones del nervio torácico largo de Bell. Revisión de conceptos terapéuticos / Long thoracic nerve of Bell. Review of therapeutic management

Las lesiones del nervio torácico producen parálisis del serrato anterior y originan una deformidad característica (escápula alata), que genera debilidad y alteraciones importantes en la movilidad del hombro. En esta revisión, se analizan conceptos sobre anatomía, etiología, presentación clínica y alternativas terapéuticas.

The long thoracic nerve injuries are manifested by a characteristic deformity called scapula alata, causing weakness, and impaired shoulder mobility. In this review current concepts of the anatomy, etiology, clinical presentation and therapeutic management are analyzed.

Proximal Variation of the Long Thoracic Nerve would be Vulnerable to Injury during an Axillary Dissection

Herein, our experience of a rare variation of the long thoracic nerve during an axillary dissection in a female patient with a breast ductal carcinoma in situ (DCIS) is reported. Her long thoracic nerve was duplicated and united at its proximal and distal parts, respectively. She was a 45-year old female, with microcalcification on her left breast, which had been diagnosed as a DCIS by a stereotactic core needle biopsy. Due to the diffuse distribution of lesions, a mastectomy was performed, with immediate reconstruction using a transverse rectus abdominis muscle (TRAM) free flap. After the mastectomy, an axillary dissection was performed for anastomoses of the free flap to the thoracodorsal vessels, at which point the duplicated variation of the proximal part of the long thoracic nerve was found. This variation is very rare, and would be vulnerable to injury during an axillary dissection. Therefore, surgeons should take care to avoid injury to such a nerve during axillary surgery.

Variations of the ventral rami of the brachial plexus

We studied the variations in the ventral rami of 152 brachial plexuses in 77 Korean adults. Brachial plexus were composed mostly of the fifth, sixth, seventh and eighth cervical nerves and the first thoracic nerve (77.0%). In 21.7% of the cases examined, the fourth, fifth, sixth, seventh and eighth cervical and the first thoracic nerves contributed to the plexus. A plexus composed of the fourth, fifth, sixth, seventh and eighth cervical and the first and second thoracic nerves, and a plexus composed of the fifth, sixth, seventh eighth cervical nerves were also observed. The plexuses were classified into three groups according to cephalic limitation, and the plexus of group 2 in which the whole fifth cervical nerve enters the plexus, were observed the most frequent. The average diameter of the sixth and the seventh cervical ventral rami of the plexus was greatest and that of the fifth cervical was smallest. The largest nerve entering the plexus was the sixth or the seventh cervical nerve in about 79% of cases. The dorsal scapular nerve originated from the fifth cervical ventral ramus in 110 cases (75.8%). The long thoracic nerve was formed by joining of roots from the fifth, sixth, and seventh cervical nerves in 76.0% of cases. Also, a branch to the phrenic nerve, the suprascapular nerve, a nerve to the pectoralis major muscle and a nerve to the subscapular muscle arising from the ventral rami of the plexus were observed.

Biomechanical study of rucksack paralysis / 体力科学

The rucksack paralysis is currently considered to be caused by the compression or hypertraction of brachial plexus or long thoracic nerve. However, its precise mechanism has not yet been fully clarified. In the present study, we attempted to explain the mechanisms of rucksack paralysis. For this purpose, three sets of studies were performed, i. e., (1) examinations on the exact localization of shoulder straps with the aid of radiographic analysis, (2) measurements of the compression under the straps with load cell, strain gauge and prescale, and (3) anatomical studies on the nerve pathway under the compressed area.<BR>In the experiments with six male and five female subjects, the inside edge of the strap at rest was found to run from area around the center of clavicle to the lateral side of the ribs. Finally, it went down to the inner part of the axilla. However, on tread-mill walking the position of the strap's inside edge shifted to the lateral part of the clavicle and that of the central part moved to both the acromion of the scapula and the head of the humerus. Thus, during the actual walking with rucksack, the strap was considered to move within these areas. In addition, we found that carrying a rucksack displaced the scapulae toward the median.<BR>From measurements of the compression under the strap with six male subjects, the following common findings were obtained: (1) the heaviest load was upon the upper part of the body trunk, i. e., suprascapular region (4 subjects) and clavicular region (2 subjects), and (2) the edge of the strap produced stronger compression than its center did.<BR>Anatomical studies with ten cadavers revealed that the brachial plexus might be strongly compressed in the case of muscular hypertonicity or body surface compression.<BR>The long thoracic nerve arised from the branches of the 5 th, 6 th and 7 th cervical nerve. Joined nerve trunks of the branches of the 5 th and 6 th cervical nerves frequently appeared at the lateral side of the brachial plexus. The branch of the 7 th cervical nerve joined with the nerve trunks running through the middle scalene muscle, although location of this nerve conjoining was somewhat different among various cases, i, e., at the proximal side of the second rib in seven cases and at the area between the 2 nd and 3 rd ribs in three cases. The long thoracic nerve was found to turn downwards at the second rib, and this turning point was located at the tuberosity of the serratus anterior muscle.<BR>From these results, we consider that the paralysis of the brachial plexus is caused by the load of rucksack working as a tractive external force on the nerves between the clavicle and neck, while it acts as a compressive external force on the nerves from coracoid processes to the axillary region. On the other hand, the paralysis of the long thoracic nerve seems to occur due to hypertraction of or compression over the tuberosity of the serratus anterior muscle of the second rib.