Journal of Experimental & Clinical Cancer Research 2009, 28:45 http://www.jeccr.com/content/28/1/45 aeTFprhigapetueivarcerecalyne8pcetaoblfethaectlievfet asbhdou cldtieornisfusnhcotwion 2a0ndmtohnetchosspmoestiocp- The acceptable active abduction function and the cosmetic appearance of the left shoulder is shown 20 months postoperatively. sion could contribute to an unacceptable scar and the patient's negative emotional response to the surgical out- come. Nonetheless, achieving a safe surgical margin must take priority over cosmetics in these cases. During allograft reconstruction, internal fixation provides static stability for shoulder joints and attachment sites for soft tissues. Two or more plates can be used to stabilize the scapular allograft on the spine, glenoid, or the lateral and medial border of the scapula thereby achieving equal force distribution on the allograft during shoulder abduc- tion and scapula rotation. The tips of the acromion and coracoid should be preserved which will provide anchor points for the scapular allografts. The attachment sites for muscles and the coracoclavicular ligament should be pre- served and the reconstruction of the acromion and cora- coid with the bony insertion of the deltoid restores the suspension mechanism of the scapula, securing the stabil- ity of glenohumeral joint. The fixation of the clavicle also maintains the effect of clavicle suspension for the shoul- der joint. The retroversion angle and downward slope of the glenoid surface should also be an important consider- ation. As previously reported [15,19], the glenoid tilts at an angle of 8° ± 4° to the posterior and the downward slope of the glenoid has an average angle of 4°. Changes to these angles may result in multidirectional instability or anteroposterior dislocation. Therefore, the articular capsule requires reconstruction prior to the abductor mechanism in both glenoid-saved and glenoid-resected allograft procedures. The deltoid and supraspinatus muscles are the primary muscles involved in shoulder movement. The deltoid is also the predominant muscle responsible for maintaining stability of the shoulder, suspending the humerus, permitting shoulder abduction, and contributing to the contour of the shoulder. As such, the deltoid requires special atten- tion during reconstruction of the scapular girdle [2,6- 9,14]. Wittig et al. [10] also demonstrated the importance of covering the scapula prostheses with a vascularized and functional deltoid. Reconstruction of the residual or unin- volved deltoid also allows for myodesis with the func- tional trapezius and acts as a potential abductor mechanism. Therefore, the articular capsule, together with the deltoid, provides a dynamic stabilizer for the gleno- humeral joint and both structures should be recon- structed whenever possible. Preservation of both the rotator cuff and deltoid signifi- cantly influenced the eventual shoulder abduction capac- ity in the series of patients described herein. Yasojima et al. [20] demonstrated significant electromyogram activity of the supraspinatus and the middle deltoid during scapu- lar plane abduction. The rotator cuff provides a medially and inferiorly directed force vector on the humeral head, which stabilizes the humeral head against the glenoid [21]. In this study, four patients with adequate rotator cuff reconstruction had significantly better shoulder function compared with the three patients whose rotator cuffs were resected. Thus, it is recommended to preserve the rotator cuffs when possible, as previously suggested [2-4]. Unfor- tunately, the rotator cuffs, especially the posterosuperior ones, often require resection (as illustrated by the patients included in this case series) making it difficult to preserve the affected rotator cuff while achieving a safe surgical margin. Thus, we suggest that the remaining external rota- tor can be reattached when the posterosuperior rotator cuff is resected. In patients with a deficient rotator cuff, however, movement of the deltoid should be able to assist in achieving acceptable shoulder function [5]. Therefore, preservation of the deltoid muscle length, when possible, will help increase deltoid moment [22] and maintain shoulder abduction capacity. Additionally, the affected muscle(s) around the thoracoscapular joint is known to be less correlated with stability and function of the gleno- humeral joint and does not need to be reattached to obtain thoracoscapular rhythm. With regard to soft-tissue reconstruction, both the articu- lar capsule and deltoid play important roles in shoulder stability and function. The articular capsule acts as the ful- crum for stabilization of the glenohumeral joint, which, in turn serves as the fulcrum for shoulder abduction. Use of a scapular allograft with satisfactory shoulder func- tion has previously been demonstrated [3,4,12]. The mean ISOLS score reported in this case series was 80% but only 78.5% and 74% in the studies reported by Pritsch and Asavamongkolkul, respectively [8,6]. The glenoid- Page 8 of 10 (page number not for citation purposes)