Shoulder function and anatomy in complete obstetric brachial plexus palsy: long-term improvement after triangle tilt surgery

Abstract

Purpose: Untreated complete obstetric brachial plexus injury (COBPI) usually results in limited spontaneous recovery of shoulder function. Older methods used to treat COBPI have had questionable success, with very few studies being published. The purpose of the current study was to examine the results of triangle tilt surgery on shoulder function and development in COBPI individuals.

Methods: This study was conducted as a retrospective chart review. Inclusion criteria were COBPI patients that had undergone the triangle tilt procedure from 2005 to 2009 and were between the ages of 9 months and 12 years. COBPI was defined as permanent injury to all five nerve roots (C5-T1), with significant degradation in development and function of the hand. Twenty-five patients with a mean age of 5 (0.75-12) years were followed up clinically for more than 2 years.

Results: The triangle tilt procedure resulted in demonstrable clinical enhancements with appreciable improvements in shoulder function, glenoid version, and humeral head congruity. There was a significant increase in the overall Mallet score (2.4 points, p < 0.0001) following surgical correction in patients that were followed up for more than 2 years.

Conclusions: The results of this study demonstrate that COBPI patients who develop SHEAR and medial rotation contracture deformities can benefit from the triangle tilt surgery, which improves shoulder function and anatomy across a range of pediatric ages. Despite these patients presenting late for surgery in general (5 years), significant improvements were observed in their glenohumeral (GH) dysplasia and their ability to perform shoulder and arm movements following surgery.

Fig. 1

Pre-triangle tilt acromioclavicular plane in a shoulder with SHEAR deformity. Notice the abnormal position of the ACT (sides defined by clavicular shaft and acromion process and base as an imaginary line connecting their medial ends) in relation to the humeral head. The ACT lies in the acromioclavicular plane

Fig. 2

Neutral anatomic acromioclavicular plane. Notice the separation of the distal ACT-humeral head complex from the normally positioned scapula. Post-triangle tilt, the reversal of the anterior tilt of the ACT allows a natural rotation of the humeral head back into a more neutral position within the glenoid fossa

Fig. 3

Artist’s rendering of the triangle tilt surgery and anterior capsule release. Illustrated are osteotomies of the clavicle, scapula, and acromion process, along with glenohumeral capsulodesis and anterior capsule release

Fig. 4

Artist’s rendering of acromioclavicular interface before and after triangle tilt surgery. Notice the bone realignment following triangle tilt surgery

Fig. 5

Schematic drawing showing the method of calculating glenoscapular angle (glenoid version θ) and posterior subluxation of the humeral head. The scapular line that connects the medial aspect of the scapula and the mid-glenoid is drawn. A second line is drawn connecting the posterior and anterior margins of the glenoid. 90° is subtracted from the angle of the posterior medial quadrant defined by these lines to determine the glenoid version θ. A line perpendicular to the scapular line is drawn and the percentage of posterior subluxation is defined as the ratio of the distance from the scapular line to the anterior portion of the head to the diameter of the humeral head (LM/LN × 100)

Fig. 6

The Nath Modification of Mallet’s System: clinical scoring of function. In addition to assessing the classical functions of the Modified Mallet system, supination and the resting position are evaluated. To further define deformity, fixed forearm supination (positions 2S, 3S, and 4S) as well as external rotation position (5E) are scored

Fig. 7

Axial CT images of a complete plexus injury patient illustrating a humeral head posterior subluxation preceding surgery and b corrective repositioning of the humeral head post-surgery. R indicates right, L indicates left, H indicates humeral head, G indicates glenoid

Fig. 8

3D-CT images of a complete plexus injury patient showing a preoperative impingement of the acromioclavicular triangle on the humeral head b postoperative release of the acromioclavicular triangle allowing for repositioning of humeral head

Fig. 9

Shoulder functions in a patient with COBPI before (a–c) and after (d–f) triangle tilt surgery. Movements include hand-to-mouth (a, d), hands to spine (b, e) and hands to neck (c, f). The ability to perform all of these functions improved significantly postoperatively

Fig. 10

Position of arm at rest a prior to triangle tilt surgery; b 1 year post-triangle tilt