[Compression neuropathy of the suprascapular nerve in high performance volleyball players]

Electromyography and nerve conduction velocity for the evaluation of the infraspinatus muscle and the suprascapular nerve in professional beach volleyball players

BACKGROUND

Beach volleyball is an overhead sport with a high prevalence of infraspinatus muscle atrophy of the hitting shoulder.

HYPOTHESIS

Infraspinatus muscle atrophy seems to be caused by a repetitive traction injury of the suprascapular nerve. Early pathological findings might be assessed with surface electromyography (EMG) and nerve conduction velocity (NCV) measurements.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Fully competitive professional beach volleyball players were assessed with a structured interview, shoulder examination, strength measurements (external rotation and elevation), and neurophysiological examination (surface EMG and NCV of the infraspinatus and supraspinatus muscles and the suprascapular nerve, respectively) during the Beach Volleyball Grand Slam tournament 2010 in Klagenfurt, Austria.

RESULTS

Thirty-five men with an average age of 28 years were examined. Visible infraspinatus atrophy was found in 12 players (34%), of which 8 (23%) had slight atrophy and 4 (11%) had severe atrophy. External rotation (90%; P < .006) and elevation strength (93%; P = .03) were significantly lower in the hitting shoulder. Electromyography revealed a higher activation pattern in the infraspinatus muscle of the hitting arm in players with no or slight atrophy (P = .001) but a significantly lower activation pattern in players with severe atrophy (P = .013). Nerve conduction velocity measurements showed a significant higher latency and lower amplitude in the hitting shoulder of the total study group and the subgroup with infraspinatus atrophy.

CONCLUSION

Professional beach volleyball players have a high frequency of infraspinatus atrophy (34%) and significantly reduced shoulder strength of the hitting shoulder. These findings are not associated with demographic factors. Electromyography and NCV measurements suggest a suprascapular nerve involvement caused by repetitive strain injuries of the nerve. External rotation strength measurements and NCV measurements can detect a side-to-side difference early, while EMG may show compensation mechanisms for progressive damaging of the suprascapular nerve and, as a result, loss of infraspinatus muscle strength.

Nerve injury about the shoulder in athletes, part 1: suprascapular nerve and axillary nerve

Nerve injuries about the shoulder in athletes are being recognized with increasing frequency. Prompt and correct diagnosis of these injuries is important to treat the patient and to understand the potential complications and natural history so as to appropriately counsel athletes. This 2-part article is a review and an overview of the current state of knowledge regarding some of the more common nerve injuries seen about the shoulder in athletes.

Acute isolated suprascapular nerve palsy limited to the infraspinatus muscle: a case report

Suprascapular nerve palsy resulting in isolated weakness of the infraspinatus muscle is subtle at its onset and must be differentiated from cervical radiculopathy or bone and joint diseases of the shoulder, especially in the presence of pain. The literature suggests an association of cumulative trauma with ganglionic cyst formation and entrapment neuropathy of the suprascapular nerve in the spinoglenoid notch. Here we present clinical, electrodiagnostic, and radiologic features in a young patient who presented with a 2-week history of isolated, painless weakness of the right shoulder. His electromyography showed acute denervation of the right infraspinatus muscle. Magnetic resonance imaging revealed a ganglionic cyst in the spinoglenoid fossa and edema in the infraspinatus muscle consistent with denervation. The patient recovered after removal of the cyst.

Suprascapular neuropathy related to a glenohumeral joint cyst

A man with shoulder pain and complaints of weakness had examination findings consistent with a suprascapular neuropathy with predominant involvement of the infraspinatus muscle. Electrodiagnostic studies confirmed an axon-loss suprascapular neuropathy with greater involvement of the infraspinatus muscle. Magnetic resonance imaging (MRI) demonstrated a large ganglion cyst originating from the glenohumeral joint. The clinical, electrodiagnostic, and radiologic evaluation of suprascapular neuropathy is discussed.

Suprascapular nerve rotator cuff compression syndrome in volleyball players

Selective denervation of the infraspinatus muscle producing weakness and wasting has been reported in certain sports (eg, volleyball and baseball). Nerve kinking or friction caused by excessive infraspinatus motion and compression by superior or inferior transverse scapular ligament or ganglions have been proposed as possible causes. However, in extreme abduction with full external rotation of the shoulder, the medial tendinous margin between the infraspinatus and supraspinatus muscles impinges strongly against the lateral edge of scapular spine, compressing the intervening infraspinatus branch of the suprascapular nerve. Spinaglenoid notchplasty has been performed in 5 elite volleyball players with infraspinatus neuropathy, allowing recovery of shoulder function in all patients and correction of infraspinatus muscle wasting. All returned to the same or higher level of volleyball by 8 months after surgery. An alternative cause of infraspinatus compromise in volleyball players is proposed and has been treated surgically with satisfactory outcome.

Suprascapular nerve entrapment: experience with 28 cases

Suprascapular nerve entrapment (SNE) in the suprascapular notch is a rare entity that must be considered in the differential diagnosis of radicular pain, as well as that of shoulder discomfort. Over a period of 10 years (1985-1995), the authors treated 28 cases of SNE in 27 patients by surgical decompression of the nerve. One patient underwent operation bilaterally within 5 years. Five patients presented with a history of trauma to the shoulder region. In three patients, a ganglion cyst was the origin of the nerve lesion. In 16 patients, the nerve problem was primarily related to athletic activities. Eight of these patients were professional volleyball players. In the remaining three patients, there was no relationship between the nerve lesion and trauma or athletic activities. Twenty-one patients (22 cases) complained of pain located over the suprascapular notch. Seventeen patients had paresis and atrophy of both the supraspinatus (SS) and infraspinatus (IS) muscles. In 10 patients only the IS muscle was involved. One patient exhibited a sensory deficit over the posterior portion of the shoulder. Electromyography was performed in all cases. The mean follow-up period in the 25 cases (24 patients) that could be evaluated was 20.8 months (range 3-70 months). Nineteen of 22 cases with preoperative pain could be evaluated. Sixteen of these patients were completely free of pain after surgery and three patients found their pain had improved. Motor function in the SS muscle improved in 86.7% and motor function in the IS muscle in 70.8% of cases. Atrophy of the SS muscle resolved in 80.7% and atrophy of the IS muscle in 50% of cases. Surgical treatment of SNE is indicated after failed conservative treatment and in cases of atrophy of the SS and IS muscles. The authors recommend the posterior approach, which minimizes risks and complications and produces good postoperative results.

Muscular imbalance and shoulder pain in volleyball attackers

OBJECTIVE

In overhead sports such as volleyball, baseball, or tennis shoulder problems are very common. The aim of this study was to identify features which may correlate with shoulder problems in volleyball attackers.

METHODS

30 competitive volleyball attackers (mean age 25 years) were included in the study; 15 were suffering from shoulder pain and 15 had no history of shoulder pain. The results were compared with those of a control group of 15 recreational athletes without any overhead sports activities.

RESULTS

Volleyball attackers have a different muscular and capsular pattern at the playing shoulder compared to the opposite shoulder. Their playing shoulder is depressed, the scapula lateralised, and the dorsal muscles and the posterior and inferior part of the shoulder capsule shortened. These differences were of more significance in volleyball attackers with shoulder pain than in volleyball players without shoulder pain. In contrast to recreational athletes without any overhead sports activity, there were no significant difference in the comparison of the two shoulders. The histories, clinical and sonographic findings did not reveal further typical features for volleyball attackers with shoulder pain.

CONCLUSIONS

Muscular balance of the shoulder girdle is very important in this sport. It is therefore imperative to include adequate stretching and muscular training programme for the prevention, as well as for therapy, of shoulder pain in volleyball attackers.