Suprascapular neuropathy

Muscle degeneration in rotator cuff tears

Rotator cuff tears are among the most common injuries seen by orthopedic surgeons. Although small- and medium-sized tears do well after arthroscopic and open repair, large and massive tears have been shown to develop marked muscle atrophy and fatty infiltration within the rotator cuff muscles. These pathologic changes have been found to be independent predictors of failed surgical repair with poor functional outcomes. To understand the pathophysiology of rotator cuff disease, we must first develop an understanding of the changes that occur within the cuff muscles themselves. The purpose of this review is to summarize the molecular pathways behind muscular degeneration and emphasize new findings related to the clinical relevance of muscle atrophy and fatty infiltration seen with rotator cuff tears. Understanding these molecular pathways will help guide further research and treatment options that can aim to alter expression of these pathways and improve outcomes after surgical repair of massive rotator cuff tears.

Suprascapular neuropathy: diagnosis and management

Although historically considered a diagnosis of exclusion, suprascapular neuropathy may be more common than once believed, as more recent reports are describing the condition as a cause of substantial pain and weakness in patients with and without concomitant shoulder pathology. The etiology is traction or compression of the suprascapular nerve. This can result from a space-occupying lesion, such as a ganglion cyst, or a traction injury as a result of repetitive overhead activities. More recent studies have cited cases of traction injuries occurring with retraction of a large rotator cuff tear. Atrophy of the infraspinatus and/or supraspinatus rotator cuff muscles with resultant weakness in forward flexion and/or external rotation of the shoulder on physical examination may be demonstrated. Magnetic resonance imaging (MRI) is the preferred modality to assess atrophy of the rotator cuff muscles as well as assess potential causes of suprascapular nerve compression. Electromyography and nerve conduction velocity studies remain the gold standard for confirmation of the diagnosis of suprascapular neuropathy; however, nerve pain may occur even in the setting of a negative electromyography. Initial management is usually nonoperative, consisting of activity modification, physical therapy, and nonsteroidal anti-inflammatory drugs. Surgical intervention is considered for patients with nerve compression by an external source or for symptoms refractory to conservative measures. Decompression of the suprascapular nerve may be accomplished through an open approach, although arthroscopic surgical approaches have become more common in the past several years.

Severe atrophy and fatty degeneration of the infraspinatus muscle due to isolated infraspinatus tendon tear

Atrophy of both the supraspinatus and infraspinatus muscles is usually caused by chronic rotator cuff tear, but may also derive from suprascapular nerve entrapment at the spinoglenoid notch. Isolated infraspinatus muscle atrophy is uncommon, and typically associates with suprascapular nerve entrapment occurring distal to the spinoglenoid notch. However, isolated atrophy of the infraspinatus muscle due to insertional tear of the infraspinatus tendon may also occur. We present a case of a 43-year-old male with isolated infraspinatus muscle atrophy and fatty degeneration following an isolated full-thickness infraspinatus tendon tear at the insertion site on the humerus. While it is important to rule out other causes of infraspinatus muscle atrophy, such as concomitant rotator cuff tendon/muscle pathology or suprascapular nerve palsy, we present this case to increase awareness of this uncommon clinical presentation and the potential implications for treatment.