Scapulothoracic dissociation. A case report

A 26-year-old man sustained a scapulothoracic dissociation (STD) as a result of severe shoulder girdle trauma. In this recently described syndrome, multiple fractures of the upper extremity and closed disruption of the scapula from the thorax are combined with damage to the local neurovascular structures. The occurrence of blunt subclavian arterial injury and STD indicates the possibility of severe brachial plexus lesions.     

Scapulothoracic dissociation: evaluation and management

Scapulothoracic dissociation is an infrequent injury with potentially devastating outcomes. Knowledge of this injury is based on small patient series and case reports. The aim of this article is to review the evaluation, management and functional outcomes following scapulothoracic dissociation. Often caused by high traction forces applied to the shoulder girdle, there is a complete loss of the scapulothoracic articulation with lateral scapular displacement and intact skin. This is frequently associated with muscular, ligamentous and osseous injuries to the shoulder girdle, vascular injuries to the subclavian, or axillary, vessels and brachial plexus lesions. In the acute setting, the timely diagnosis of the associated neurovascular injuries is crucial. Severe neurovascular and soft tissue compromise often requires an early above-elbow amputation. Further, complete brachial plexus avulsions are associated with a limited potential for functional recovery.     

A neurovascular complication after scapulothoracic arthrodesis

Facioscapulohumeral muscular dystrophy is a progressive disorder characterized by weakness in the muscles of the face, shoulder girdle and upper limbs, and variable lower extremity weakness. The muscles that stabilize the scapula are significantly weak, although the deltoid usually is preserved. With attempted shoulder abduction, the unstable scapula protrudes, elevates, and internally rotates. Scapulothoracic arthrodesis stabilizes the scapula and improves active range of motion and function of the shoulder. Appropriate scapular positioning on the chest wall has been described previously. The current authors review a neurovascular complication after scapulothoracic arthrodesis in which the scapula was positioned as described in the literature. Immediate repositioning resulted in an excellent long-term outcome. Previous recommendations as to scapular position must be taken simply as guidelines. Intraoperative monitoring of neurovascular function in the upper extremity should prevent this complication.     

Scapulothoracic dissociation

Scapulothoracic dissociation is a rare entity that consists of disruption of the scapulothoracic articulation. The mechanism of injury is probably traction caused by a blunt force to the shoulder girdle. This lesion is characterized by massive soft-tissue swelling of the shoulder; lateral displacement of the scapula, measured radiographically; an injury to bone (an acromioclavicular separation, a displaced fracture of the clavicle, or a sternoclavicular disruption); a severe neurovascular injury; and a variety of upper and lower-extremity fractures. We treated fifteen patients who had this lesion, most of whom had several associated injuries. Three patients died: two from exsanguination and one from a cardiac arrest. In most patients, the damaged artery was repaired and the brachial plexus was explored. All of the twelve patients who had a complete brachial-plexus injury were left with a flail upper extremity. Most patients refused amputation.     

The Snapping Scapula: Diagnosis and Treatment

As a largely under-recognized problem, snapping scapula stems from the disruption of normal mechanics in scapulothoracic articulation. It is especially common in the young, active patient population, and symptoms are frequently seen with overhead and throwing motions. Understanding the anatomy of the scapula and surrounding neurovascular structures is crucial in making a differential diagnosis and providing both nonoperative and surgical treatments. Common causes of snapping scapula include bursitis, muscle abnormality, and bony or soft-tissue abnormalities. Anatomic variations, such as excessive forward curvature of the superomedial border of the scapula, may also be a cause for snapping. Benign tumor conditions of the scapula can also predispose one to snapping scapula syndrome and should be thoroughly investigated during the course of treatment. Patients with snapping scapula syndrome typically present with a history of pain with overhead activities. Snapping scapula is associated with audible and palpable crepitus near the superomedial border of the scapula. Various imaging studies may be used to rule out soft-tissue and bony masses, which may cause impingement at the scapulothoracic articulation. In most cases nonoperative treatment is curative and includes physical therapy for scapular muscle strengthening and nonsteroidal anti-inflammatory medications. Corticosteroid injections may also be used for therapeutic and diagnostic purposes. In most cases overuse injuries and repetitive strains respond well to nonoperative treatments. When nonoperative measures fail, surgery is a proven modality, especially if a soft-tissue or bony mass is implicated. Both open and arthroscopic techniques have been described with predictable results.     

An alternative portal for scapulothoracic arthroscopy

Access to the superior angle of the scapula during scapulothoracic arthroscopy with current standard portals can be difficult. A safe, effective alternative portal for scapulothoracic arthroscopy, located superior to the scapula, is described, which enables easier resection of the superomedial angle for treatment of the snapping scapula.     

A continuum between scapulothoracic dissociation and traumatic forequarter amputation: a review of the literature

Both traumatic forequarter amputation and scapulothoracic dissociation are rare and life-threatening injuries. We present the case of a 31-year old woman who was ejected from a car after a motor vehicle accident and sustained an apparent partial forequarter amputation. Upon examination her injury was found to share many characteristics with a scapulothoracic dissociation injury. With both injuries mortality is high and prompt diagnosis and treatment imperative. By viewing scapulothoracic dissociation and forequarter amputation as a continuum faster recognition and appropriate treatment may be implemented for these devastating injuries.     

The painful scapulothoracic articulation: surgical management

To clarify the indications and effectiveness of surgical decompression for scapulothoracic bursitis, 16 patients were evaluated, who during a 5-year period, had surgical treatment of refractory pain and snapping in the scapulothoracic region. Twelve women and four men with a mean age of 41 years had one of five methods of surgical decompression of the scapulothoracic articulation. Six patients had an open resection of the scapulothoracic bursa with excision of the superomedial portion of the scapula, two had this procedure using an arthroscopic method, and six had a combined approach with arthroscopic scapulothoracic bursectomy and open resection of the superomedial scapula through a small incision. One patient had an arthroscopic and one an open scapulothoracic bursectomy only. At final followup of an average of 36 months (range, 24-69 months), 81% of patients reported satisfaction with the procedure and indicated they would have it again based on the relief they obtained from pain. The Simple Shoulder Test was 9.8 (range, 2-12). Although there was no statistical difference in the success using any given technique, we thought that the combined open and arthroscopic approach was the most effective, and surgical treatment is an acceptable method for treatment of refractory painful scapulothoracic bursitis.     

Brachial plexus injuries in scapulothoracic dissociation

The rare condition of scapulothoracic dissociation (STD) is characterized by a lateral displacement of the scapula from the thoracic cage following severe trauma to the scapular girdle. This study presents an analysis of five STDs. There were three supraclavicular brachial plexus palsies and two retro- and infraclavicular palsies. Recovery of elbow flexion was obtained in only two cases. Nerve damage dominates the prognosis and nerve recovery only rarely occurs. Nerve surgery should attempt to reestablish elbow flexion.     

Scapulothoracic penetration of a Beath pin: an unusual complication of arthroscopic Bankart suture repair

The arthroscopic Bankart suture repair technique is an alternative to open procedures that control anterior shoulder instability. A case is presented in which a Beath pin traveled through the scapula and penetrated the scapulothoracic articulation during arthroscopic Bankart repair. The authors caution that strict adherence to Morgan's technique should minimize complications with this procedure.     

Treatment of painful scapulothoracic crepitus by resection of the superomedial angle of the scapula. A report of three cases

Three healthy young male manual laborers developed painful unilateral scapulothoracic crepitus arising from the superomedial angle of the scapula. There was a history of trauma in two of the patients. Asymmetric prominence of the superomedial angle of the scapula was demonstrated by computed tomography (CT) scanning in two patients. All three patients were successfully treated by resection of the superomedial angle of the scapula. The resected tissue was histologically normal in each case. Painful scapulothoracic crepitus arising from the superomedial angle of the scapula is associated with local trauma, is best investigated with a CT scan, and if unresponsive to prolonged conservative measures, can be successfully treated by resection of the superomedial angle of the scapula.     

Scapulothoracic anatomy for the arthroscopist

Because endoscopic management has recently been introduced as treatment for painful subscapular snapping, we designed a cadaveric study to identify the boundaries of the scapulothoracic spaces and the relationship of important neurovascular structures to safe portal sites for arthroscopic surgery. We studied eight fresh, unembalmed cadaveric shoulders by anatomic dissection alone and eight fresh, unembalmed cadaveric shoulders by dissection after arthroscopy. We noted the following findings: (1) the scapulothoracic articulation has two triangular spaces, the serratus anterior space and the subscapularis space, that are divided obliquely by the serratus anterior muscle; (2) the boundaries of the larger serratus anterior space include the chest wall anteriorly, the serratus anterior muscle posteriorly, and the rhomboids medially; (3) the boundaries of the subscapularis space are the serratus anterior muscle anteriorly, the subscapularis muscle posteriorly, and the axilla laterally; and (4) a well-defined bursa occupies the serratus anterior space. Based on these findings, we recommend that portals for arthroscopic surgery should be inferior to the spine of the scapula and three to four fingerbreadths from the vertebral border of the scapula (1) to avoid the neurovascular structures at the superomedial angle of the scapula, (2) to avoid the dorsosacpular nerve and artery, and (3) to prevent perpendicular orientation of the arthroscope to the lateral chest wall.     

Traumatic scapulothoracic dissociation

Scapulothoracic dissociation is an infrequent injury with a potentially devastating outcome. The diagnosis is based on clinical and radiographic findings of forequarter disruption. These include massive soft tissue swelling of the shoulder, displacement of the scapula and neurovascular injuries (brachial plexus, subclavian artery and osseous-ligamentous injuries). The mechanism of injury appears to be the delivery of severe rotational force sheering the shoulder girdle from its chest wall attachments around the scapula, shoulder joint and at the clavicle. Early recognition of the entity and aggressive treatment are crucial. Outcome is not dependent on management of the arterial injury, but rather on the severity of the neurological deficit.     

Anatomy of the scapulothoracic articulation

Four fresh frozen human cadavers (eight extremities) consisting of the head, neck, thorax, and entire upper extremities were used for dissection of the scapulothoracic articulation. In each specimen, the spinal accessory nerve, all relevant muscle insertions, and bursae were identified and measured. The structures of the scapulothoracic articulation can be divided into superficial, intermediate, and deep layers. The superficial layer consists of the trapezius, latissimus dorsi, and an inconsistent bursa between the inferior angle of the scapula and the latissimus dorsi. The intermediate layer consists of the levator scapulae, rhomboid minor and major, spinal accessory nerve, and scapulotrapezial bursa located between the superomedial scapula and the overlying trapezius. In all specimens, the spinal accessory nerve traveled intimately along the wall of the scapulotrapezial bursa, an average of 2.7 cm lateral to the superomedial angle of the scapula. The deep layer consists of the serratus anterior, subscapularis, and two bursae: one between the serratus and the thorax, the scapulothoracic bursa; and one between the subscapularis and the serratus, the subscapularis bursa.     

Hook retraction for scapulothoracic arthroscopy

Scapulothoracic arthroscopy is an established method for evaluating the articulation between the thoracic cage and the scapula. The "chicken-wing" position is often used to enhance visualization of the scapulothoracic space. There are situations in which the chicken-wing position is not feasible or practical, such as in simultaneous arthroscopy of both joints. In this article, we describe a new technique that aids in arthroscopy of the scapulothoracic joint, particularly when the chicken-wing position is unavailable.     

Editorial Commentary: Snapping Scapula Syndrome: Predictors of Outcomes After Arthroscopic Treatment

Snapping scapula syndrome and scapulothoracic bursitis are rare, often painful or functionally limiting conditions that can present owing to underlying anatomic abnormalities or can be idiopathic in nature. When there are no underlying structural abnormalities, diagnosis can be challenging and frequently patients will present with chronic pain having received multiple diagnostic and treatment modalities with no success. Injections into the scapulothoracic bursa, in conjunction with physical therapy, have been shown to be effective for the patient with snapping scapula syndrome and/or scapulothoracic bursitis, when recognized. Yet, some cases are recalcitrant to conservative treatment, and surgical intervention is required. As with any procedure, patient selection for surgical intervention is critical and based on the diagnostic workup—particularly, the response to diagnostic or therapeutic injections. The best surgical outcomes may be achieved in patients who receive bursectomy in conjunction with partial scapulectomy, and negative prognostic factors include older age, lower preoperative psychological score, and longer duration of symptoms.     

Subperiosteal resection of mid-clavicle in Sprengel��s deformity correction

We report the results of fifteen cases of Sprengel’s deformity treated surgically by initial subperiosteal resection of the middle third of the clavicle in conjunction with surgical release of all attachments of the scapula to the spine, excision of any omovertebral bone and resection of prominent supraspinous process of scapula. The patients included ten female and three male patients (age range at the time of operation, 3.3–10 years; mean: 6.11 years). The deformity involved the left shoulder in eight patients, the right shoulder in three and two were bilateral. All patients were followed for an average of 5.9 years (range 4–11 years). Preoperatively, the arc of total abduction (glenohumeral and scapulothoracic) ranged from 80 to 140°, and the average was 110°. The shoulders were level, and the range of motion was dramatically improved with an average range of abduction of 166.5° (range 140–180°). The age of the patients and the presence of an omovertebral bone did not influence the results. All patients and their parents expressed satisfaction with the operative results. We feel that our procedure is a simple one, which helps to improve the degree of correction, avoid neurovascular complications and has the advantage of complete regeneration of the clavicle. The technique provides an easy, safe method of repositioning the scapula at its normal level.     

Scapulothoracic and scapholunate dissociation in the ipsilateral upper limb of a trauma victim

Scapulothoracic dissociation is a rare and complex injury pattern with varied presentation.Here we describe a case of a 32-year-old male who presented with scapulothoracic dissociation associated with brachial plexus injury,along with scapholunate dissociation.We also propose an injury mechanism that might link the two injury patterns,suggesting that the association might be more than by chance.The patient was managed according to established trauma care and resuscitation protocols followed by open reduction and internal fixation of the clavicle fracture,and fixation of scapholunate dissociation and had a successful outcome at follow-up.     

Scapulothoracic and glenohumeral kinematics following an external rotation fatigue protocol

STUDY DESIGN: Repeated-measures experimental design. OBJECTIVE: To determine the effects of shoulder external rotator muscle fatigue on 3-dimensional scapulothoracic and glenohumeral kinematics. BACKGROUND: The external rotator muscles of the shoulder are important for normal shoulder function. Impaired performance of these muscles has been observed in subjects with impingement syndrome and it is possible that external rotator muscle fatigue leads to altered kinematics of the shoulder girdle. METHODS AND MEASURES: Twenty subjects without a history of shoulder pathology participated in this study. Three-dimensional scapulothoracic and glenohumeral kinematics were determined from electromagnetic sensors attached to the scapula, humerus, and thorax. Surface electromyographic (EMG) data were collected from the upper and lower trapezius, serratus anterior, anterior and posterior deltoid, and infraspinatus muscles. Median power frequency (MPF) values were derived from the raw EMG data and were used to indicate the degree of local muscle fatigue. Kinematic and EMG measures were collected prior to and immediately following the performance of a shoulder external rotation fatigue protocol. RESULTS: After completing the fatigue protocol subjects demonstrated less external rotation of the humerus. Additionally, they had less posterior tilt of the scapula in the beginning phase of arm elevation, and more scapular upward rotation and clavicular retraction in the mid ranges of arm elevation. CONCLUSIONS: Performance of an external rotation fatigue protocol results in altered scapulothoracic and glenohumeral kinematics. Further studies are needed to investigate the effects of external rotator muscle fatigue on scapulothoracic and glenohumeral kinematics in subjects with shoulder pathology.