The periclavicular space is a conduit for the brachial plexus and subclavian-axillary vascular system. Changes in its shape/form generated by alteration in the anatomy of its bounding structures, e.g. clavicle malunion, cause distortion of the containing structures, particularly during arm motion, leading to syndromes of thoracic outlet stenosis etc., or alterations of scapular posture with potential reduction in shoulder function.

Aim of this study was developing an in vitro methodology for systematic and repeatable measurements of the clinically poorly characterized periclavicular space during arm motion using CT-imaging and computer-aided 3D-methodologies.

A radiolucent frame, mountable to the CT-table, was constructed to fix an upper torso in an upright position with the shoulder joint lying in the isocentre. The centrally osteotomized humerus is fixed to a semi-circular bracket mounted centrally at the end of the frame. All arm movements (ante-/retroversion, abduction/elevation, in-/external rotation) can be set and scanned in a defined and reproducible manner. Clavicle fractures healed in malposition can be simulated by osteotomy and fixation using a titanium/carbon external fixator.

During image processing the first rib served as fixed reference in space. Clavicle, scapula and humerus were registered, segmented, and triangulated. The different positions were displayed as superimposed surface meshes and measurements performed automatically. Initial results of an intact shoulder girdle demonstrated that different arm positions including ante-/retroversion and abduction/elevation resulted solely in a transverse movement of the clavicle along/parallel to the first rib maintaining the periclavicular space.

A radiolucent frame enabling systematic and reproducible CT scanning of upper torsos in various arm movements was developed and utilized to characterize the effect on the 3D volume of the periclavicular space. Initial results demonstrated exclusively transverse movement of the clavicle along/parallel to the first rib maintaining the periclavicular space during arm positions within a physiological range of motion.

Background

Re-attachment of tendon to bone is challenging with surgical repair failing in up to 90% of cases. Poor biological healing is common and characterised by the formation of weak scar tissue. Previous work has demonstrated that decellularised allogenic demineralised bone matrix (DBM) regenerates a physiologic enthesis. Xenografts offer a more cost-effective option but concerns over their immunogenicity have been raised. We hypothesised that augmentation of a healing tendon-bone interface with DBM incorporated with autologous mesenchymal stem cells (MSCs) would result in improved function, and restoration of the native enthesis, with no difference between xenogenic and allogenic scaffolds.

Summary Statement

Sprengel's deformity is a rare congenital anomaly, with scapula malposition. We present a unique subgroup of Sprengel's possessing a cleithrum, an ancestral remnant of shoulder-girdle development found in bony-fish. This challenges management providing valuable insight into scapular embryology and development.