Treatment of Posterior Shoulder Dislocation in Obstetric Brachial Plexus Palsy Using Subscapularis Release and Tendon Transfer
Citation: Treatment of Posterior Shoulder Dislocation in Obstetric Brachial Plexus Palsy Using Subscapularis Release and Tendon Transfer. American Research Journal of Orthopedics and Traumatology. 2017; 2(1): 1-11.
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Background: The muscle imbalance of the shoulder results in weak external rotation and abduction. Active internal rotation and adduction can cause glenohumeral joint deformity with late posterior dislocation.
Patients and Methods: In this prospective study from 2004 to 2009, thirty four patients, 18 females and 16 males with mean age of 4 years (1-7 years). The right side was affected in 19 cases while the left side was affected in 15 cases. All patients were suffering from obstetrical brachial plexus palsy (OBPP) with internal rotation contracture and defective shoulder abduction plus posterior dislocation or subluxation of the humeral head. These patients were treated with soft tissue release (subscapularis slide and anterior soft tissues release) with or without tendon transfer (latissimus dorsi & teres major to infraspinatus).
Conclusion: The subscapularis release can provide objective functional benefit, but this degraded over time. The transfer of teres major and latissimus dorsi to infraspinatus is a useful procedure for correction of defective shoulder abduction and external rotation in (OBPP) as it increases the stabilizing action of the rotator cuff allowing the deltoid muscle to act with maximal force.
The incidence of obstetric brachial plexus palsy (OBPP) is 1 to 4 /1000 live births, and about 50% of these cases have good recovery without late deformity. Partial recovery of the C5, C6, C7 roots gives muscle imbalance, and delay of recovery causes biceps muscle contracture 1-3. The residual muscle imbalance of the shoulder in the form of weak external rotation and abduction with active internal rotation and adduction can cause glenohumeral joint deformity with late dislocation posteriorly 4-6. The advances in microvascular surgery and early reconstruction of the brachial plexus reduced the need for palliative treatment as rehabilitation by physiotherapy, orthosis, and braces which are difficult to apply in this young age and failure occurs in severe cases 7.
For treatment of this deformity there were many surgical options, such as anterior release of contractures in internal rotators and adductors of the shoulder as in Sever operation 8. Enhancing this technique tendon transfer of the latissimus dorsi and teres major to the lateral aspect of the humerus was added by L’Episcopo 9. Later, the technique of transferring the latissimus dorsi and teres major to the rotator cuff was suggested by Hoffer et al 10. Bone procedures as derotation osteotomy of the proximal humerus are available to correct these deformities.Pedicle and free muscle transfers in cases of paralytic shoulder are other options.The criteria of selection of the specific procedure were based on the age of the patient and the degree of glenohumeral deformity on the preoperative computed CT or MRI. As long as the glenohumeral joint is congruent, tendon and muscle transfer can be performed at a later date, but they should be considered at earlier times to maximize functional recovery 11. Shoulder reconstruction expected to improve both arm appearance and some of the hand functions as reaching the head or mouth and raising the hand above the shoulder3.
The aim of this prospective study is to evaluate the results of 34 patients with OBPP treated surgically with anterior release and tendon transfer of teres major and latissimus dorsi.
PATIENTS AND METHODS
In a prospective study from 2004 to 2009, thirty four patients, 18 females and 16 males with mean age of 4 years (1-7years). The right side was affected in 19 cases while the left side was affected in 15 cases. All patients were suffering from obstetrical brachial plexus palsy (OBPP) with internal rotation contracture and defective shoulder abduction with posterior dislocation or subluxation of the humeral head. These patients were treated with soft tissue release (subscapularis slide and anterior soft tissues release) with or without tendon transfer (latissimus dorsi & teres major to infraspinatus).
Sixteen cases (47 %) were delivered at hospital while eighteen cases (53 %) were delivered at home. fifteen cases (44 %) had definite history of difficult labor ,and five cases (14.7 %) were breech delivery. Two cases (5.9%) had associated fracture clavicle. In 9 cases (26.5%) the baby was the first child of his/her parents. Birth weight in 17 cases (50%) was over 4kg (3.6 to 4.5 kg) which appear to be the most important risk factor. 32 cases (94.1%) had no previous surgery and were treated by physiotherapy. only 2 cases (5.9%) had primary microsurgical repair of the plexus. We found complete paralysis (C5 , C6 , C7 , C8 , T1 roots affected) in 21 cases (61.8%) at the time of birth and 13cases (38.2 %) were partial (C5 , C6 only affected. All cases 34 were suffering from medial rotation contracture, 21 cases (61.8%) were dislocated and 13 cases (38.2%) were subluxated. Standard plain X-ray of the shoulder and computerized tomography (CT) were routinely done for all patients for precise assessment of the deformity (Glenoid retroversion and degree of posterior subluxation of the humeral head). Follow up (CT) of both shoulders were performed for all 34 cases postoperatively. We used mallet 12 grading and modified Gilbert systems 13 for the shoulder function (Fig 1) & (Table 1&2)
Rationale of Treatment
The aim of the operations was to relocate the dislocated glenohumeral joint and to alleviate secondary deformities arising from incomplete recovery following nonsurgical management or residual deformities following primary reconstruction.
All 34 patients underwent subscapularis release. Added tendon transfers were needed in 21 cases. Posterior capsulorraphy was done in three cases for residual glenohumeral subluxation.
Technique for Subscapularis Release
The patients were placed in lateral decubitus. The affected shoulder and torso were prepared to the mid-line anteriorly and posteriorly. A longitudinal incision was made along the lateral border of the scapula, and dissection was carried out down to the latissimus dorsi muscle, which was retracted inferiorly, and the inferior angle of the scapula was identified and stabilized with towel clips. The subscapularis muscle is readily identified and elevated in its entirety from the anterior surface of the scapula with use of electrocautery or a periosteal elevator.
Dissection was then performed in a subperiosteal fashion, progressing from the inferior angle upward. An external rotation force on the humerus was applied gently throughout the release to confirm adequate release of the muscle and elimination of the contracture. Care must be taken to avoid injury of the subscapular artery and nerve running anteromedial to the glenoid neck and anterior to the subscapularis muscle, and over the scapular notch. After complete release of the subscapularis muscle, the wound was closed over a suction drain.
Technique for Tendon Transfer
The patient is lying in lateral decubitus, with the arm is abducted 120° and externally rotated. A curved wide C shaped incision following the lateral border of the scapula and the posterior margin and the deltoid 2-3 cm posterior to the posterior axillary fold to avoid tethering scar. After dissection of the deep fascia, the tendons were identified, and the latissimus dorsi tendon was released at its insertion at the proximal humerus. In our work, the tendon of latissimus dorsi was thin and weak in 3 cases (below 2 years of age) where the transfer of the latissimus dorsi was augmented by terse major muscle transfer as described by Edward et al (2000)14.
To avoid injury of their neurovascular bundles, care was done to avoid excessive dissection on the under surface of the latissimus dorsi and teres major. The interval between the poster-inferior margins of the deltoid muscle and the rotator cuff was then developed, and with the arm maximally abducted and externally rotated, the released tendons of teres major and latissimus dorsi were sutured as superior as possible to the infraspinatus tendon. We always putted in mind that the tension of the transferred tendons should keep the arm in some abduction and external rotation.
At the completion of the operation, the arm was held in the appropriate position and a plaster body jacket, prepared before the operation, was applied and above elbow cast was applied and attached to the body jacket with the shoulder in 90 of abduction, full external rotation and 20 forward elevation in order to take pressure off the brachial plexus. One month postoperative a splint was applied full-time to maintain the arm in abduction and external rotation position for 1.5 months, removing it only to bathe and for gentle range-of-motion exercises, which are begun at six weeks. The patient then wears the splint only at night for an additional1.5 months to be discontinued six months postoperatively (Fig 2).
We used SPSS 17 program for windows: Results were expressed as mean ± standard deviation for quantitative variables, and as percentages for qualitative variables. Paired T-test was used to determine the effect of surgery on shoulder motion.
The follow up ranged from 24 months to 62 months with an average of 30 months. The mean shoulder abduction in all patients was improved from (85.9o ± 18.9 SD) preoperative to (132.0 ± 18.7 SD) postoperative. The mean shoulder external rotation in all patients was improved from (-17.9 o ± 16.6 SD) preoperative to (66.5 o ± 14.9SD) postoperative (P ≥ 0.001). The mean improvement of shoulder external rotation was 84.4 degrees, thus the average gain in shoulder external rotation was 37%. The improvement in both abduction and external rotation was statistically significant (Table 3). With correlation between the age at surgery (in months) and the improvement of shoulder abduction and external rotation postoperatively, we found a highly significant negative correlation (P ≥ 0.001) between age at surgery and average improvement of shoulder abduction and external rotation (chart 1) (i.e. the older the age at surgery, the less the improvement in shoulder range of abduction and external rotation (Fig 3&4).