Vulnerability of long thoracic nerve: an anatomic study

Scapula winging secondary to prone plank exercise: a case report

Background: Scapular winging occurs when the muscles responsible for the stabilization of the scapula (serratus anterior, trapezius, rhomboid major and minor) are paralyzed due to any reason. The most frequently observed neurological aetiology is serratus anterior muscle dysfunction due to long thoracic nerve palsy. The cause of long thoracic nerve palsy may be traumatic or atraumatic. It has been previously reported that a wide variety of sports can cause long thoracic nerve palsy.Clinical presentation: In this article, we report a case of unilateral winging of the scapula due to injury to the long thoracic nerve which occurred secondary to performing prone plank exercises; the likes of which has not previously been described in the literature and which may have occurred due to the exercise being performed incorrectly. In this patient, nerve recovery became evident one month following conservative treatment and cessation of plank exercises.Conclusion: Long thoracic nerve injury may have occurred due to increased and incorrect scapula loading during plank exercises. In order to prevent compression neuropathies caused by load transfer imbalance, attention should be paid to correct positioning whilst performing core stabilization exercises such as the prone plank.

Neurolysis of the distal segment of the long thoracic nerve for the treatment of scapular winging due to serratus anterior palsy: a continuous series of 73 cases

BACKGROUND

Serratus anterior (SA) palsy following mechanical injury to the long thoracic nerve (LTN) is the most common cause of scapular winging. This study aimed to identify the factors influencing the outcome of neurolysis of the distal segment of the LTN. We hypothesized that poor results are due to duration before surgery and to persistent scapulothoracic dysfunction.

METHODS

A retrospective study was conducted. The inclusion criteria were partial or complete isolated noniatrogenic SA paralysis of at least 4-month duration with preoperative electrophysiologic assessment confirming the neurogenic origin without signs of reinnervation.

RESULTS

Seventy-three patients were assessed at 45 days, 6 months, and 24 months after neurolysis of the distal segment of the LTN. At the last follow-up, improvement was excellent in 38 (52%), good in 22 cases (30%), moderate in 6 (8%), and poor in 7 (10%). No patient showed deterioration in outcomes since the beginning of follow-up. Scapular winging was no longer present in 46 cases (63%), while it was minimal in 23 (31.5%). In 4 cases (5.5%), winging was similar to the preoperative condition.

DISCUSSION

The best outcomes occurred in patients who presented without compensatory muscle pain and who were treated within 12 months of paralysis. Beyond this time frame, neurolysis can still provide useful functional improvement and avoid palliative surgery.

CONCLUSION

Neurolysis of the distal segment of the LTN is a safe and reliable procedure. This technique allows treatment of SA muscle palsy and corrects scapular winging with excellent or good outcomes in 82% of cases.

A Review of Upper Extremity Peripheral Nerve Injuries in Throwing Athletes

Peripheral nerve injuries in the upper extremities may be common in throwing athletes as the throwing motion places extreme stress on the dominant arm. The combination of extreme stress along with repetitive microtrauma from throwing uniquely places the throwing athlete at elevated risk of upper extremity peripheral nerve injury. However, because symptoms can be non-specific and frequent co-exist with pathology in the upper extremity, the diagnosis of peripheral nerve injury is often delayed. Diagnosis of peripheral nerve injuries may require a combination of history and physical exam, diagnostic imaging, electrodiagnostic testing, and diagnostic ultrasound guided injections. The primary management should include physical therapy focusing on throwing mechanics and kinetic chain evaluation. However, some athletes require surgical intervention if symptoms do not improve with conservative management. The purpose of this focused narrative review is to highlight upper extremity peripheral neuropathies reported in throwing athletes and to provide an overview of the appropriate clinical diagnosis and management of the throwing athlete with a peripheral nerve injury. This article is protected by copyright. All rights reserved.

Analysis of the positional relationship of the long thoracic nerve considering clinical treatment

INTRODUCTION

The long thoracic nerve (LTN) has a risk of being damaged during chest surgery and should be considered when performing anesthesia such as a serratus anterior plane block (SAPB). We analyzed the relationship between landmarks-the fourth to ninth intercostal space (ICS) at the midaxillary line (MAL), through which the distal part of the LTN passes-and the LTN.

MATERIALS AND METHODS

We used 25 specimens from 17 embalmed Korean cadavers. The MAL, level of rib and ICS, and regions 5 cm anteroposterior to the MAL (aMAL/pMAL) were established to measure the position of the LTN crossing the MAL, pathway of the LTN, and entering points of the LTN to the SA.

RESULTS

The LTN crossed the MAL in 76% of the specimens. The LTN crossed the MAL within the fifth to sixth rib level in 70.8%. Seventy-six percent of the branches entered the SA within the fourth to sixth ICS. The fifth rib and ICS were the most frequent regions aMAL; however, several branches were found pMAL. The LTN entered the SA in 92.6% of the specimens within 3 cm anterior and 1 cm posterior to the MAL.

CONCLUSIONS

We set the danger zone as 4 cm near the MAL at the fourth to sixth ICS for thoracotomy. In addition, we proposed the fifth ICS in aMAL at the superficial plane as the alternative injection point for SAPB when blocking the LTN, and the fifth ICS in pMAL at the deep plane to prevent blocking the LTN.

Current concepts review: peripheral neuropathies of the shoulder in the young athlete

Peripheral neuropathies of the shoulder and upper extremity are uncommon injuries that may affect the young athletic population. When present, they can result in significant pain and functional impairment. The cause of peripheral neuropathy in young athletes may be an acute, traumatic injury such as a shoulder dislocation or a direct blow to the shoulder girdle. Alternatively, repetitive overuse with resultant compression or traction of a nerve over time may also result in neuropathy; overhead athletes and throwers may be particularly susceptible to this mechanism of nerve injury. Regardless of etiology, young athletes typically present with activity-related pain, paresthesias, and dysfunction of the affected upper extremity. In addition to physical examination, diagnostic studies such as radiographs and magnetic resonance imaging (MRI) are commonly performed as part of an initial evaluation and electrodiagnostic studies may be used to confirm the diagnosis of peripheral neuropathy. Electrodiagnostic studies may consist of electromyography, which evaluates the electrical activity produced by skeletal muscles, and/or a nerve conduction study, which evaluates a nerve's ability to transmit an electrical signal. Although data are not robust, clinical outcomes for young patients with activity-related peripheral neuropathies of the shoulder are generally good, with most young athletes reporting both symptomatic and functional improvement after treatment.

Intercostal Nerve to Long Thoracic Nerve Transfer for the Treatment of Winged Scapula: A Cadaveric Feasibility Study

There are very few surgical options available for treating a patient with winged scapula caused by a long thoracic nerve (LTN) injury. Therefore, we devised a novel technique based on a cadaveric dissection whereby regional intercostal nerves (ICN) were harvested and transposed to the adjacent LTN in 10 embalmed cadavers (20 sides). The LTN was identified along the lateral border of the serratus anterior and ICNs were identified at the mid-axillary line inferior to the lower edge of the pectoralis major muscle. Along the mid-clavicular line, each ICN was transected and transposed to the adjacent LTN. The length and diameter of each ICN available for mobilization to the LTN were measured. All measurements were made with microcalipers. Within the operative site, the mean proximal and distal diameters of the LTN were 1.6 and 1.1 mm, respectively. The adjacent ICN had a mean diameter of 1.3 mm. On all sides, the ICN branches were easily transposed to the adjacent LTN without any tension. Anastomosis to the LTN was performed to the third through sixth ICN provided each intercostal was preserved and mobilized anteriorly at least as far as the midclavicular line. The end to end size match between donor and LTN was appropriate on all sides. We found that it is feasible to harvest adjacent ICNs and move these to the adjacent LTN. Such a procedure, after being confirmed in patients, might offer a new technique for restoring protraction following an LTN injury.

Long Thoracic Nerve Injury Caused by Overhead Weight Lifting Leading to Scapular Dyskinesis and Medial Scapular Winging

Scapular winging represents a rare phenomenon that most commonly results from nerve damage to either the long thoracic nerve, spinal accessory nerve, or, less commonly, the dorsal scapular nerve. This injury results in an abnormal scapulohumeral interaction during kinetic motion known as scapular dyskinesis. In this case report, the patient presented with scapular dyskinesis and medial scapular winging caused by overhead weight-lifting exercises, and a long thoracic nerve injury was diagnosed. Physicians are encouraged to consider long thoracic nerve damage in a patient with a history of repetitive overhead movements who presents with scapular dyskinesis and the corresponding restriction of overhead arm motions. Potential mechanisms of injury and treatment options are also discussed.

Syndrome of fascial incarceration of the long thoracic nerve: winged scapula

OBJECTIVE

To analyze the results from early intervention surgery in patients with the syndrome of fascial incarceration of the long thoracic nerve and consequent winged scapula.

METHODS

Six patients with a syndrome of nerve trapping without specific nerve strain limitations were followed up.

RESULTS

The patients achieved improvement of their symptoms 6-20 months after the procedure. The motor symptoms completely disappeared, without any persistent pain. The medial deformity of the winged scapula improved in all cases, without any residual esthetic disorders.

CONCLUSION

The approach of early surgical release seems to be a better predictor for recovery from non-traumatic paralysis of the anterior serratus muscle.

Isolated paralysis of the serratus anterior muscle: surgical release of the distal segment of the long thoracic nerve in 52 patients

INTRODUCTION

Isolated serratus anterior (SA) paralysis is a rare condition that is secondary to direct trauma or overuse. Patients complain of neuropathic pain and/or muscle pain secondary to overexertion of the other shoulder stabilizing muscles. As the long thoracic nerve (LTN) passes along the thorax, it can be compressed by blood vessels and/or fibrotic tissue. The goal of the current study was to evaluate the outcomes of surgical release of the distal segment of the LTN in cases of isolated SA paralysis.

PATIENTS AND METHODS

This was a retrospective study of 52 consecutive cases operated on between 1997 and 2012. The average patient age was 32 years (range 13-70). Patients had been suffering from paralysis for an average of 2 years (range 4-259 months); the paralysis was complete in 52% of cases. Every patient underwent a preoperative electroneuromyography (ENMG) assessment to confirm that only the SA was affected and there were no signs of re-innervation.

RESULTS

Every patient had abnormal intraoperative findings. There were no complications. All patients showed at least partial improvement following the procedure. The improvement was excellent or good in 45 cases (86.7%), moderate in 4 cases (7.7%) and slight in 3 cases (5.6%). In 32 cases (61.5%), the winged scapula was completely corrected; it was less prominent in 19 cases and was unchanged in one case. The best outcomes following surgical release occurred in patients who presented without preoperative or neuropathic pain and were treated within 18 months of paralysis.

DISCUSSION

Isolated SA paralysis due to mechanical injury resembles entrapment neuropathy. We discovered signs of LTN compression or restriction during surgery. Surgical release of the distal segment of the LTN is a simple, effective treatment for pain that provides complete motor recovery when performed within the first 12 months of the paralysis.

LEVEL OF EVIDENCE

IV.

Long thoracic nerve release for scapular winging: clinical study of a continuous series of eight patients

Scapular winging secondary to serratus anterior muscle palsy is a rare pathology. It is usually due to a lesion in the thoracic part of the long thoracic nerve following violent upper-limb stretching with compression on the nerve by the anterior branch of thoracodorsal artery at the "crow's foot landmark" where the artery crosses in front of the nerve. Scapular winging causes upper-limb pain, fatigability or impotence. Diagnosis is clinical and management initially conservative. When functional treatment by physiotherapy fails to bring recovery within 6 months and electromyography (EMG) shows increased distal latencies, neurolysis may be suggested. Muscle transfer and scapula-thoracic arthrodesis are considered as palliative treatments. We report a single-surgeon experience of nine open neurolyses of the thoracic part of the long thoracic nerve in eight patients. At 6 months' follow-up, no patients showed continuing signs of winged scapula. Control EMG showed significant reduction in distal latency; Constant scores showed improvement, and VAS-assessed pain was considerably reduced. Neurolysis would thus seem to be the first-line surgical attitude of choice in case of compression confirmed on EMG. The present results would need to be confirmed in larger studies with longer follow-up, but this is made difficult by the rarity of this pathology.

LEVEL OF EVIDENCE

III.

Scapular winging: anatomical review, diagnosis, and treatments

Scapular winging is a rare debilitating condition that leads to limited functional activity of the upper extremity. It is the result of numerous causes, including traumatic, iatrogenic, and idiopathic processes that most often result in nerve injury and paralysis of either the serratus anterior, trapezius, or rhomboid muscles. Diagnosis is easily made upon visible inspection of the scapula, with serratus anterior paralysis resulting in medial winging of the scapula. This is in contrast to the lateral winging generated by trapezius and rhomboid paralysis. Most cases of serratus anterior paralysis spontaneously resolve within 24 months, while conservative treatment of trapezius paralysis is less effective. A conservative course of treatment is usually followed for rhomboid paralysis. To allow time for spontaneous recovery, a 6–24 month course of conservative treatment is often recommended, after which if there is no recovery, patients become candidates for corrective surgery.

The contralateral long thoracic nerve as a donor for upper brachial plexus neurotization procedures: cadaveric feasibility study

Object

Various donor nerves, including the ipsilateral long thoracic nerve (LTN), have been used for brachial plexus neurotization procedures. Neurotization to proximal branches of the brachial plexus using the contralateral long thoracic nerve (LTN) has, to the authors' knowledge, not been previously explored.

Methods

In an attempt to identify an additional nerve donor candidate for proximal brachial plexus neurotization, the authors dissected the LTN in 8 adult human cadavers. The nerve was transected at its distal termination and then passed deep to the clavicle and axillary neurovascular bundle. This passed segment of nerve was then tunneled subcutaneously and contralaterally across the neck to a supra- and infraclavicular exposure of the suprascapular and musculocutaneous nerves. Measurements were made of the length and diameter of the LTN.

Results

All specimens were found to have a LTN that could be brought to the aforementioned contralateral nerves. Neural connections remained tension free with left and right neck rotation of ~ 45°. The mean length of the LTN was 22 cm with a range of 18–27 cm. The overall mean diameter of this nerve was 3.0 mm. No gross evidence of injury to surrounding neurovascular structures was identified in any specimen.

Conclusions

Based on the results of this cadaveric study, the use of the contralateral LTN may be considered for neurotization of the proximal musculocutaneous and suprascapular nerves.

Winging of the scapula: An unusual complication of needle thoracocentesis

Needle thoracocentesis is a common interventional procedure and is generally considered to be safe. Major complications associated with this procedure are uncommon. Here we describe a rare instance of winging of the scapula following needle thoracocentesis.

The long thoracic nerve as a donor for facial nerve reanimation procedures: cadaveric feasibility study

Object

Injury of the facial nerve with resultant facial muscle paralysis may result in other significant complications such as corneal ulceration. To the authors' knowledge, neurotization to the facial nerve using the long thoracic nerve (LTN), a nerve used previously for neurotization to other branches of the brachial plexus, has not been explored previously.

Methods

In an attempt to identify an additional nerve donor candidate for facial nerve neurotization, 8 adult human cadavers (16 sides) underwent dissection of the LTN, which was passed deep to the clavicle and axillary neurovascular bundle. The facial nerve was localized from the stylomastoid foramen onto the face, and the distal cut end of the previously dissected LTN was tunneled to this location. Measurements were made of the length and diameter of the LTN. Long thoracic nerve innervation to the first and second digitations of the serratus anterior was maintained on all sides.

Results

All specimens were found to have an LTN with more than enough length to be tunneled superiorly, tension-free to the extracranial facial nerve. Connections remained tensionless with left and right head rotation of up to 45°. The mean length of this part of the LTN was 18 cm with a range of 15–22 cm. The overall mean diameter of this nerve was 2.5 mm. No evidence of injury to the surrounding neurovascular structures was identified on gross examination.

Conclusions

To the authors' knowledge, the LTN has not been previously examined as a donor nerve for facial nerve reanimation procedures. Based on the results of this cadaveric study, the use of the LTN may be considered for such surgical maneuvers.

Brachial plexus lesions after backpack carriage in young adults

Carrying a heavy backpack exerts compression on shoulders, with the potential to cause brachial plexopathy. We evaluated the incidence and predisposing factors of compression plexopathy of the shoulder region in 152,095 military conscripts, hypothesizing that a low body mass index and poor physical fitness predispose to the plexus lesion. Reports of conscripts with neural lesions of the upper arm associated with load carriage were reviewed retrospectively for details associated with the condition onset, symptoms, signs, nerve conduction studies, and electromyographic examinations. Height, weight, and physical fitness scores were obtained from their military training data. The incidence of neural compression after shoulder load carriage in Finnish soldiers was 53.7 (95% confidence interval, 39.5-67.8) per 100,000 conscripts per year. The long thoracic nerve was affected in 19, the axillary nerve in 13, the suprascapular nerve in seven, and the musculocutaneous nerve in six patients. Four patients (7%) had hereditary neuropathy with susceptibility to pressure palsies (HNPP). Symptoms were induced by lighter loads in patients with HNPP. Vulnerability to brachial plexopathy was not predictable from body structure or physical fitness level. To prevent these lesions, awareness of the condition and its symptoms should be increased and backpack designs should be improved.

Case reports: long thoracic nerve palsy after using a single axillary crutch

We describe a 42-year-old patient who incurred long thoracic nerve palsy after using one axillary crutch. The patient sustained fractures to his left tibia and fibula. The fractures required internal fixation with a locked intramedullary nail and postoperative restricted weightbearing using axillary crutches. When weightbearing was progressed, the patient began using one axillary crutch on the right side. The resulting asymmetric gait pattern forced the crutch onto his chest wall, which led to right-sided long thoracic nerve palsy. The patient had not recovered 6 months after the injury. When providing axillary crutches, clinicians must consider potential compromise of the long thoracic nerve and the brachial plexus if the crutch is used inappropriately.

Surgical anatomy of the cervical and infraclavicular parts of the long thoracic nerve

OBJECT

There is insufficient information in the neurosurgical literature regarding the long thoracic nerve (LTN). Many neurosurgical procedures necessitate a thorough understanding of this nerve's anatomy, for example, brachial plexus exploration/repair, passes for ventriculoperitoneal shunt placement, pleural placement of a ventriculopleural shunt, and scalenotomy. In the present study the authors seek to elucidate further the surgical anatomy of this structure.

METHODS

Eighteen cadaveric sides were dissected of the LTN, anatomical relationships were observed, and measurements were obtained between it and surrounding osseous landmarks. The LTN had a mean length of 27 +/- 4.5 cm (mean +/- standard deviation) and a mean diameter of 3 +/- 2.5 mm. The distance from the angle of the mandible to the most proximal portion of the LTN was a mean of 6 +/- 1.1 cm. The distance from this proximal portion of the LTN to the carotid tubercle was a mean of 3.3 +/- 2 cm. The LTN was located a mean 2.8 cm posterior to the clavicle. In 61% of all sides the C-7 component of the LTN joined the C-5 and C-6 components of the LTN at the level of the second rib posterior to the axillary artery. In one right-sided specimen the C-5 component directly innervated the upper two digitations of the serratus anterior muscle rather than joining the C-6 and C-7 parts of this nerve. The LTN traveled posterior to the axillary vessels and trunks of the brachial plexus in all specimens. It lay between the middle and posterior scalene muscles in 56% of sides. In 11% of sides the C-5 and C-6 components of the LTN traveled through the middle scalene muscle and then combined with the C-7 contribution. In two sides, all contributions to the LTN were situated between the middle scalene muscle and brachial plexus and thus did not travel through any muscle. The C-7 contribution to the LTN was always located anterior to the middle scalene muscle. In all specimens the LTN was found within the axillary sheath superior to the clavicle. Distally, the LTN lay a mean of 15 +/- 3.4 cm lateral to the jugular notch and a mean of 22 +/- 4.2 cm lateral to the xiphoid process of the sternum.

CONCLUSIONS

The neurosurgeon should have knowledge of the topography of the LTN. The results of the present study will allow the surgeon to better localize this structure superior and inferior to the clavicle and decrease morbidity following invasive procedures.

Occupational and Sport Related Traumatic Neuropathy

BACKGROUND

Sport and occupation related traumatic nerve injury is a common problem in the United States. While the physical requirements of each pursuit place participants at risk for injury to certain peripheral nervous system structures, the vast numbers of professional and recreational pursuits limits the ability to become familiar with nerve injuries specific to each. A more pragmatic approach is to apply knowledge of mechanisms of injury, physiology of nerve injury, regional anatomy, and at-risk peripheral nervous system structures to the routine neurologic history and physical assessment to arrive at a localizing and etiologic diagnosis.

REVIEW SUMMARY

The authors discuss potential mechanisms of nerve injury, the role of electrodiagnostic testing, regional peripheral nervous system anatomic considerations and lesion localization.

CONCLUSIONS

Despite the wide variety of professionally and recreationally induced peripheral nerve injuries, application of anatomic, physiologic and mechanistic considerations allow the neurologist to make an etiologic and localizing diagnosis.

Anatomical characteristics of the upper serratus anterior: cadaver dissection

STUDY DESIGN

A descriptive study of the anatomical characteristics of the upper serratus anterior.

OBJECTIVES

To delineate the upper serratus anterior with comparison to classical descriptions of the anatomy of the muscle as a whole.

BACKGROUND

Although the serratus anterior has a major role in scapulothoracic stability, description of the separate function and anatomy of the upper, middle, and lower portions of the muscle has been limited.

METHODS AND MEASURES

Bilateral anatomical dissection of 8 cadavers (3 female and 5 male) exposed 13 serratus anterior and surrounding structures for review. The number of serrations, attachment sites, length, and girth of the upper serratus anterior were measured.

RESULTS

The upper serratus anterior presented with dual serrations and single serrations in 7 (54%) and 6 (46%) of 13 observations, respectively. Attachments to both first and second ribs were noted in 6 (46%) of the 13 observations. The remaining proximal attachments were to the second rib only, the first rib only, and dual attachments to the second and third ribs. In all cases, cranial attachments were to the superior scapular angle blending with the levator scapulae attachment. Length ranged from 4.8 to 9.0 cm (mean +/- SD, 6.9 +/- 1.2 cm). The girth ranged from 3.0 to 8.5 cm (mean +/- SD, 6.1 +/- 1.5 cm). One or more branches of the long thoracic nerve were observed to consistently innervate the upper serratus anterior fibers.

CONCLUSION

The upper serratus anterior demonstrated wide variation in anatomy and was noted to be distinct in appearance and peripheral innervation from the middle and lower serratus anterior.

Nerve entrapment in athletes

Nerve entrapment syndromes can occur in athletes. The repetitive and vigorous use or overuse of the upper extremity makes the athlete particularly vulnerable to disorders of peripheral nerves. Understanding the clinical signs and symptoms is essential to treatment. The pertinent anatomy, clinical presentation, treatment, and rehabilitation necessary for return to sports for various nerve entrapments have been described. This should enable the physician caring for the athlete to help prevent injury and to guide appropriate treatment, if intervention becomes necessary.