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Scapulathoracic arthroscopy and scapula superior-medial border excision

    Overview

    Learn the Scapulathoracic arthroscopy and scapula superior-medial border excision surgical technique with step by step instructions on OrthOracle. Our e-learning platform contains high resolution images and a certified CME of the Scapulathoracic arthroscopy and scapula superior-medial border excision surgical procedure.
    Snapping scapula syndrome, also known as scapulothoracic crepitus or bursitis, was first described in 1867 by Boinet. The sound is produced by a tactile-acoustic phenomenon occurring as a consequence of anomalous tissue between the thoracic wall and the scapula. While in most patients these sounds are an isolated irregularity not associated with symptoms some report a clear correlation between the sounds and pain.
    The scapula has two surfaces (ventral and dorsal), three borders (superior, axillary, and vertebral), and three angles (superomedial, inferomedial, and lateral). The scapula, in its static resting position, lies approximately 5 cm lateral to the spine on the posterior aspect of the thorax, is angled 30° to 40° in relation to the coronal plane, and is tipped anteriorly 10° to 20° with respect to the sagittal plane.
    Scapulothoracic bursitis may occur following a single traumatic insult or as a result of a series of repetitive motions of the scapulothoracic joint. In most cases, the bursitis is believed to be caused by abnormal motion between the anterior surface of the scapula and the thoracic cage
    Scapulothoracic crepitus may be produced by an unusual shape of the scapula. Approximately 6% of scapulae demonstrate a hook-shaped prominence, known as the Luschka tubercle, at their superomedial angle. This tubercle may enlarge and articulate with the thoracic cage, resulting in painful crepitus.
    Osteochondroma is the most prevalent benign tumor of the scapula and has been implicated as a common cause of snapping scapula syndrome. Other, less common, skeletal causes of scapulothoracic crepitus include skeletal exostoses and other osseous tumors, especially if they arise from the ventral surface of the scapula, and fracture malunion of either the ribs or the scapula. The scapula is also the second most frequent location of chondrosarcoma, which must be considered in the differential diagnosis of any lesion in the scapulothoracic space.
    Scapulothoracic bursitis may also occur following loss of dynamic control of scapular motion. Abnormal scapular motion can be caused by muscle overuse, muscle imbalance following nerve injury, or pathological conditions of the glenohumeral joint. Muscle atrophy secondary to nerve injury, trauma, or prior operative treatment can lead to diminished soft-tissue interposition between the scapula and the thoracic cage, resulting in scapulothoracic crepitus and pain. When soft-tissue interposition is diminished, the scapula tilts, and thus a normally shaped scapula can appear to have an abnormally curved shape and dig into the chest wall. The superomedial angle of the scapula then impinges along the chest wall during scapulothoracic motion and creates inflammation in the scapulothoracic space. Atrophy of the serratus anterior following injury to the long thoracic nerve as well as subscapularis atrophy in patients with thoracic outlet syndrome have also been implicated as etiologies of scapulothoracic crepitus.
    Normal scapular motion along the thoracic cage is particularly important to athletes, and a history of overuse during activities such as swimming, pitching, weight training, gymnastics, and football has been implicated in the onset of symptoms.


    Indications

    SYMPTOMS & EXAMINATION
    Patients with snapping scapula syndrome primarily report activity-related pain and crepitus centred around the scapula. These symptoms may have an insidious onset, occur after a change in activity pattern, or be associated with trauma
    One should inquire about the frequency, level, and character of sports activities because those who engage in repetitive throwing, swimming, gymnastics, or weight-lifting are particularly susceptible to the development of scapular dyskinesis or bursitis
    The spine must first be inspected for any excessive curvature as this will create an abnormal contour about the thoracic cage, which in turn will directly alter scapular motion. Patients should also be assessed for sources of referred pain, including cervical radiculopathy, neurological injuries, and pathological changes in the glenohumeral joint
    The shoulder girdle should then be inspected for any scapular asymmetry. Tenderness at the medial scapular border over the superomedial and/or inferomedial bursae. Adduction and internal rotation of the shoulder allow these borders to be accessed for easier palpation. Patients often know how to reproduce the snapping by elevating and depressing the shoulder, and when they do so the crepitus can be localized from the undersurface of the scapula. The active and passive ranges of motion of the shoulder should be carefully examined for any limitations.
    The strength of the scapular musculature, specifically the trapezius, rhomboids, levator scapulae, serratus anterior, and latissimus dorsi muscles, should also be assessed. The trapezius muscle strength is evaluated by having the patient shrug the shoulders against resistance. The rhomboids and levator scapulae can be tested by having the patient place the hands on the hips and push the elbows backward against resistance. The serratus anterior is assessed by having the patient press against a wall with an outstretched arm while the examiner palpates the scapula for winging. The latissimus dorsi is tested with downward and backward pressure of the arm against resistance while the examiner palpates the inferomedial angle of the scapula. However, static manual muscle testing may not be sufficiently sensitive to detect subtle weakness in these muscles.
    In the presence of a lesion, so-called clunking may be observed when the arm is abducted from 90° to 180° Pseudo-winging of the scapula can be observed if a skeletal lesion pushes against the thorax to displace the scapula away from the body.

    IMAGING
    Standard radiographs of the scapula include a true anteroposterior view, a tangential trans-scapular (or Y) view and an axillary lateral view. These projections help identify skeletal irregularities such as osteochondromas, a Luschka tubercle, rib abnormalities, or alterations at the superomedial or inferomedial angle of the scapula. Commonly the imaging is entirely normal.
    MRI – will delineate soft tissue masses and associated pathology. Muscle atrophy can also be detected.
    CT- to assess bony anatomy. Can be used to undertake a guided injection into the scapulothoracic space for diagnosistic and therapeutic purposes.
    If a neurological injury is suspected, nerve conduction studies (electromyography and/or measurement of nerve conduction velocities) can be performed to determine whether the results correlate with those of the clinical examination.

    ALTERNATIVE OPERATIVE TREATMENT
    The majority of patients with scapulothoracic crepitus or bursitis can be managed successfully without operative treatment.
    The goals of rehabilitation for patients with snapping scapula syndrome are improving muscle strength and balance, addressing postural conditions (such as excessive thoracic kyphosis), and core strengthening. A corticosteroid injection can help with pain control in order to facilitate therapy.
    It is the authors preference to undertake the injection under CT control in order to ensure the steroid and local anaesthetic has be place in the correct location. This is then used as a diagnostic test to confirm that the pain is originating from the scapulothoracic joint and that the crepitus is not an asymptomatic incidental finding.

    CONTRAINDICATIONS
    It is the authors preference to undertake the injection under CT control in order to ensure the steroid and local anaesthetic has be place in the correct location. This is then used as a diagnostic test to confirm that the pain is originating from the scapulothoracic joint and that the crepitus is not an asymptomatic incidental finding.

    Setup

    The patient set up requires a standard operative table with a bean bag to allow lateral positioning. A standard 5mm arthroscope is used.

    Operation

    The patient is positioned on the table in a floppy lateral position with the patient lying more prone than supine.
    The operative arm is placed in maximum internal rotation with the arm behind the back so-called chicken wing position as this then brings the scapula medial border more prominent.

    The anatomical borders are then drawn out on the patient and the portal positions marked.
    The initial viewing portal is placed midway between the spine of the scapular and the inferior tip. The working portal is located at the level of the scapular spine.
    The portal positions are placed approximately 2cm medial to the medial border of the scapular in order to avoid injury to the nerve to levator scapulae.

    Initial portal wound is made with an eleven blade, this blade is used to penetrate just the skin.

    The Rhomboid muscle is then split using a small curved clip. The curve of the clip is aimed upwards away from the chect wall and under the scapula. The clip is then opened in order to spread the muscle layer and allow easier insertion of the arthroscopy cannula.

    The arthroscope is inserted with the trocar aiming away from the chest wall and underneath the scapula in to the sub-scapula space. Care must be taken in order to avoid plunging too deeply.

    The initial view is usually one of muscle tissue as the tendency is to insert the arthroscope in to the subscapularis muscle due to fear of penetrating the chest cavity.
    The scope is simply withdrawn until bursal tissue is seen.
    The bursas appearance is one of typical cobwebs as shown in the picture.

    Spinal needle is then used to locate under direct vision the working portal at the level of the scapula spine. The angle of insertion of the needle should match the angle of the arthroscope.

    Once the position of the needle is satisfactory the portal is made using a eleven blade and a small clip as previously described.

    A shaver is then inserted through the working portal and bursal tissue is resected.

    Bursal tissue is removed under direct vision.

    Any scar tissue or fibrous bands are removed until the space is completely clear, particularly in the area of the superior medial boarder of the scapula.
    Care is taken not to go too medial superiorly due to the risk of suprascapular nerve injury.

    A needle is then placed at the superior medial border of the scapula and used to confirm its location arthroscopically. 1 or 2 needles cant be inserted in order to delineate the superior medial boarders’ boundaries.

    An ArthroWand is then used to clear away the subscapularis muscle so that superior medial border is clearly exposed.

    The superior medial boarder is exposed to a similar degree as the acromion when undertaking a sunacromial decompression.

    When fully exposed a standard 4.2mm burr is used to resect the superior medial border until flat. The resection is carried out similar to the that of an acromion. The resection begins medially and progresses laterally until flat.

    Before completion a switching stick is inserted through the working portal and its position in the subscapula space confirmed under direct vision.

    The arthroscope is then passed over the switching stick in order to ensure the scope enters the subscapula space. This allows the superior medial border to be viewed from a more perpendicular angle.

    The burr is then inserted through the initial viewing portal and the superior medial border co-planed ensuring that it is completely flat compared to the body of the scapula. There are no anatomic landmarks to guide resection and this must be judged relative to the scapula body. It has been suggested that a 20mm x20mm area should be removed, however this should be individualised to each patient.


    The view from the initial working portal allows a more perpendicular assessment of the scapula curvature. The body of the scapula is used as a reference to limit resection.

    This is the completed resection. The original curvature of the superior medial boarder has been completely removed.

    Once happy with the resection local anaesthetic is placed in to the bursa and around the portal wounds. Sutures are not usually required. The wounds are dressed and the patient is placed in a sling for compfort.

    Post-operative position of the patient in the floppy lateral position, lying slightly prone.

    Post Operative

    The patient is placed in a simple sling for comfort but is allowed to mobilise as pain allows.
    Gentle passive motion is initiated immediately to avoid stiffness. Active and active assisted range of motion is then begun, together with isometric exercises. After 8 weeks, strengthening of the periscapular muscles begins.
    Patients are encouraged to commence scapula strengthening and core training as soon as possible in order to restore posture and scapula mechanics.

    Recommended Reading

    Islam et al. reviewed fourteen patients with a mean age of 27.6 years. Mean follow up was 35.7 months. Pain visual analogue score improved significantly from a mean of 8.8 preoperatively to 2.5 postoperatively (P value 0.00002). There was also a significant improvement in Oxford Shoulder Score from a mean of 10.8 to 40.9 (P= 0.00001). Mean crepitus score significantly decreased from 2.6 to 0.21 (p < 0.00001). Crepitus completely resolved in eleven patients. In three there was residual palpable crepitus but they had good pain relief.
    Menge et al reviewed 74 patients at a mean 3.4 years following arthroscopic surgery for snapping scapula syndrome. Eight scapulae failed initial surgical management (10.9%) because of recurrent pain and underwent revision surgery at a mean of 309 days (range, 120-917 days). After surgery, there was a significant improvement in all outcome scores, including SF-12 physical component summary score, from 39.2 to 45.4 (P = .002); SF-12 mental component summary score, from 45.0 to 49.6 (P = .023); American Shoulder and Elbow Surgeons score, from 52.6 to 75.8 (P < .001); and score on the short version of the Disabilities of the Arm, Shoulder and Hand questionnaire, from 40.2 to 24.2 (P = .001). The median patient satisfaction rating was 7 of 10. Greater age, lower preoperative psychological score, and longer duration of symptoms before surgery correlated with lower postoperative outcome scores.


    References.
    Outcome of Scapulothoracic Arthroscopy for Painful Snapping Scapula. Islam SU, Choudhry MN, Akbar S, Waseem M. Open Orthop J. 2017 Aug 21;11:785-793.
    Arthroscopic Treatment of Snapping Scapula Syndrome: Outcomes at Minimum of 2 Years. Menge TJ, Horan MP, Tahal DS, Mitchell JJ, Katthagen JC, Millett PJ. Arthroscopy. 2017 Apr;33(4):726-732.
    Technique and outcomes of arthroscopic scapulothoracic bursectomy and partial scapulectomy. Millett PJ, Gaskill TR, Horan MP, van der Meijden OA. Arthroscopy. 2012 Dec;28(12):1776-83.
    Scapulothoracic bursitis and snapping scapula syndrome: a critical review of current evidence. Warth RJ, Spiegl UJ, Millett PJ. Am J Sports Med. 2015 Jan;43(1):236-45.
    Snapping scapula syndrome. Lazar MA, Kwon YW, Rokito AS. J Bone Joint Surg Am. 2009 Sep;91(9):2251-62.

    Reference

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