A NEW STRATEGY OF MUSCLE TRANSPOSITION FOR TREATMENT OF SHOULDER DEFORMITY CAUSED BY OBSTETRIC BRACHIAL-PLEXUS PALSY

Cross-innervation (caused by misdirection of regenerated axons), muscu lar imbalance (caused by muscle paresis or earlier recovery), and grow th are the three main causes of shoulder deformity due to obstetric br achial plexus palsy. if perioperative studies demonstrate the existenc e of muscle recovery by cross-innervation, a new strategy of muscle tr ansposition to minimize the influence of cross-innervation is used. Re lease of antagonistic muscles (pectoralis major and ter es major muscl es) and augmentation of paretic muscles (transferring teres major to t he infraspinatus muscle, reinserting both ends of the clavicular part of the pectoralis major muscle laterally) are performed for reconstruc tion. Since 1993, 29 patients having shoulder deformity caused by obst etric brachial plexus palsy underwent reconstruction utilizing this st rategy of muscle transposition. The timing for the reconstruction was at an average of 8.5 years (range, 4 to 21 years). The average shoulde r abduction following the muscle transposition was 151 degrees (i.e., average gain 104 percent, or 77 degrees) and that of external rotation was 72 degrees (average gain 200 percent, or 48 degrees). Compared wi th the patients who had no surgery for shoulder deformity caused by ob stetric brachial plexus palsy and early nerve surgery for the infant o bstetric brachial plexus palsy, the results of the strategy seem to be significantly impressive.