Management of scapular dysfunction in facioscapulohumeral muscular dystrophy: the biomechanics of winging, arthrodesis indications, techniques and outcomes

Abstract

Facioscapulohumeral muscular dystrophy (FSHD) is a common hereditary disorder which typically results in scapular winging due to wasting of the periscapular muscles affected by this condition. Scapulothoracic arthrodesis (STA) is the current surgical treatment for FSHD patients with severe winging and preserved deltoid muscle. There are several different techniques in the literature such as multifilament cables alone and cable or cerclage wires combined with single or multiple plates. We prefer cables without plates as it provides independent strong fixation points and strongly recommend utilization of autograft. The functional results of studies report that regardless of the technique used, shoulder elevation and thus quality of life is improved, as shown with outcome scores. There are several complications associated with STA. Pulmonary complications are common and usually resolve spontaneously. Meticulous surgical technique and effective postoperative analgesia may reduce the incidence. Scapular complications which are associated with the fixation may be encountered in the early or late period, which are related to the learning curve of the surgeon. In conclusion, STA is a reliable solution to a major problem in FSHD patients that helps them maintain their activities of daily living until a cure for the disease is found. A successful result is strongly dependent on patient selection, and a multidisciplinary team of neurologists, geneticists and orthopaedic surgeons is required to achieve good results.

In silico analysis of rib force distribution in postscapulothoracic arthrodesis model

“…The loads are applied on the glenoid surface as illustrated in Figure 2B in the three designated loading axis of lateral‐to‐medial (ML), representing the forces exerted on the glenoid while laying down on the shoulder, and tabletop activities in physiotherapy, anterior‐to‐posterior (AP), representing the forces applying on the glenoid while the flexion‐extension movement of the shoulder; and inferior‐to‐superior (IS), representing the forces applying on the glenoid while abduction‐adduction movement of the shoulder. The scapula medial boundary is oriented to be parallel to the spinal column axis and the line that connects the inferior to superior angle of the scapula is aligned with the line that connects the T2−T7 posterior rib angles from the AP perspective through the simulations; this orientation corresponds to the physiological resting position as outlined by Eren et al 5 For loading, 100 N is applied separately in each direction; it must be noted that since homogeneous, isotropic, linear elastic material properties are utilized, the chosen initial loading is arbitrary, and the RRFs will be directly proportional to this value. Also, for a single loading axis, the RRFs will be equal in magnitude but opposite in direction for directional pairs, that is, AP, ML, or IS.…”

“…Eventually, a mixed type of scapular winging occurs. 5 As the condition worsens, patients gradually lose the ability to elevate their arms above 90 degrees, resulting in functional and cosmetic impairments.…”

“…Various scapulothoracic arthrodesis (STA) techniques are proposed in the literature; fixation via plate and cerclage wires, cerclage wires alone, multifilament cables, and screws. 5 These techniques have advantages, and the superior treatment is debatable. Also, the mentioned techniques share some pulmonary (e.g., haemothorax, pneumothorax and pulmonary effusion), scapula-based (e.g., implant irritation or failure, nonunion, scapula, and rib fractures), and neurological (brachial plexus palsy) complications.…”

“…Without the support of periscapular muscles and scapular stabilization, the force output of the deltoid muscle cannot be transferred to the arm as it lacks a point of support. Eventually, a mixed type of scapular winging occurs 5 . As the condition worsens, patients gradually lose the ability to elevate their arms above 90 degrees, resulting in functional and cosmetic impairments.…”

“…The main objective of surgical treatment of FSHD is to stabilize the scapula to the thoracic wall via fixation through ribs. Various scapulothoracic arthrodesis (STA) techniques are proposed in the literature; fixation via plate and cerclage wires, cerclage wires alone, multifilament cables, and screws 5 . These techniques have advantages, and the superior treatment is debatable.…”