Glenoid morphology in obstetrical brachial plexus lesion: a three-dimensional computed tomography study

Clavicle lengthening, a novel operation technique to reduce pain in brachial plexus birth injury patients

BACKGROUND

Brachial plexus birth injury (BPBI) can lead to an imbalance of shoulder musculature that can lead to glenohumeral contractures, and joint and osseous deformities. Glenoid hypoplasia, lengthening of coracoid and acromion, protraction, lateral rotation and elevation of the scapula, and shortening of the clavicle can be observed. As a consequence, the trapezius, levator scapulae, rhomboid, and supraspinatus muscles are overloaded in daily activities causing pain, which can be difficult to treat conservatively. It is hypothesized that operative lengthening of the clavicle may lead to a more anatomic position of the scapula and periscapular muscles, which, as a consequence, may lead to less overloading pain. This study presents the results of this new technique in patients with BPBI.

MATERIALS AND METHODS

Seven patients (median age 20 years) were included and underwent a lengthening osteotomy of the clavicle at the affective side. Preoperatively, the osseous deformities were confirmed with a computed tomography scan. Patient-reported outcome measures, Disabilities of Arm, Shoulder and Hand score, and Mallet score were evaluated pre- and postoperatively.

RESULTS

After a median of 42 (interquartile range [IQR]: 8.0) months' follow-up, all patients were satisfied with the result. The median numeric rating scale for satisfaction was 8.0 (IQR: 2). Pain decreased from a median numeric rating scale of 7.0 (IQR: 2) preoperatively to 2.0 (IQR: 3) at the final follow-up. The median Mallet score was 14.5 (IQR: 1) preoperatively and 14 (IQR: 0) at the final follow-up. The median Disabilities of Arm, Shoulder and Hand score was 36.7 (IQR: 24.1) at the final follow-up. All patients returned to their normal work without changes in working conditions.

CONCLUSION

Short-term follow-up shows that in patients with BPBI with a short clavicle at the affected side and malposition of the scapula, a lengthening osteotomy of the clavicle is a safe and promising technique to reduce pain based on overloading, without deterioration of shoulder function.

Could Subtle Obstetrical Brachial Plexus Palsy Be Related to Unilateral B Glenoid Osteoarthritis?

Background: Several factors associated with B glenoid are also linked with obstetrical brachial plexus palsy (OBPP). The purpose of this observational study was to determine the incidence of OBPP risk factors in type B patients. Methods: A cohort of 154 patients (68% men, 187 shoulders) aged 63 ± 17 years with type B glenoids completed a questionnaire comprising history of perinatal characteristics related to OBPP. A literature review was performed following the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) to estimate the incidence of OBPP risk factors in the general population. Results: Twenty-seven patients (18%) reported one or more perinatal OBPP risk factors, including shoulder dystocia (n = 4, 2.6%), macrosomia >4 kg (n = 5, 3.2%), breech delivery (n = 6, 3.9%), fetal distress (n = 8, 5.2%), maternal diabetes (n = 2, 1.3%), clavicular fracture (n = 2, 1.3%), and forceps delivery (n = 4, 2.6%). The comparison with the recent literature suggested that most perinatal OBPP risk factors were within the normal range, although the incidence of shoulder dystocia, forceps and vaginal breech deliveries exceeded the average rates. Conclusion: Perinatal factors related to OBPP did not occur in a higher frequency in patients with Walch type B OA compared to the general population, although some of them were in the high normal range.

Preoperative multislice computed tomography evaluation of shoulder deformities in brachial plexus birth palsy patients undergoing tendon transfer

BACKGROUND

Brachial plexus birth palsy (BPBP) refers to a birth related paralysis of the upper extremity. The current study was designed to evaluate the efficacy of computed tomography (CT) in the assessment of humeral head posterior subluxation and glenoid retroversion preoperatively and to evaluate whether or not bony deformity correlates with functional improvement (based on Modified Mallet Score) following tendon transfer in brachial plexus birth palsy patients.

PATIENTS AND METHODS

This prospective study included 30 patients, 15 below 4 years and 15 above 4 years old, with a mean age 3.65 ± 1.39 (range 2-8) years old. Thirteen patients were males (43.3%) and 17 were females (56.6%). The left side was affected in 13 patients (43.3%), while the right in 17 (56.7%). The Modified Mallet Score was used for clinical assessment of the shoulder function. A multislice CT scan with 3D reconstruction was used as a preoperative radiological assessment of the shoulder. An electromyography (EMG) of the muscles around the shoulder was performed. All patients were operated upon by anterior release of the internal rotators to improve the external rotation range of motion and by transfer of teres major and latissimus dorsi to improve the abduction motion through one anterior deltopectoral incision and a small posterosuperior incision. Postoperatively, the range of shoulder abduction and external rotation had been assessed after shoulder spica removal and till the end of follow up.

RESULTS

Fourteen patients (46.7%) had a normal glenoid version angle (normal range from -12° to 2°) and normal range of articulation with the glenoid (42.3%-71.4%) and 16 patients (53.3%) had an abnormal glenoid version angle and abnormal range of articulation with the glenoid. According to the Modified Mallet Score, there was a statistically significant difference in the mean value of global abduction (P = 0.04), external rotation (P = 0.03), hand to mouth (P = 0.02), hand to neck (P = 0.03) and hand to spine (P = 0.02) between the pre- and post-operative assessment of all patients. There was a statistically significant difference in the mean value of postoperative Modified Mallet Score between the patients under the age of 4 years and those above the age of 4 years. There was no statistically significant difference between the patients with normal CT angles and those with abnormal CT angles. There was no statistically significant difference in the mean value of glenoid version angle and percentage of humeral head articulation between the patients below the age of 4 years and those above 4 years (P = 0.845).

CONCLUSION

The study concluded that the glenoid version angle and humeral head articulation percentage do not negatively affect results of the tendon transfer around the shoulder in patients of upper brachial plexus birth palsy.

LEVEL OF EVIDENCE

IV.

The morphologic change of the elbow with flexion contracture in upper obstetric brachial plexus palsy

BACKGROUND

Contracture of the elbow after obstetric brachial plexus palsy (OBPP) is well known; however, details of the 3-dimensional (3D) morphologic changes in the elbow joint in OBPP have not been clarified. This study aimed to clarify the 3D morphologic changes in the elbow joint by focusing on the distal humerus with flexion contracture in upper OBPP. We tested the hypothesis that the shape of the distal humerus with flexion contracture in upper OBPP is hypoplastic in the trochlea, capitellum, and olecranon fossa.

METHODS

We retrospectively studied 20 patients with elbow flexion contracture and residual OBPP. The approximate radius of the distal humerus, the shortest distance between the olecranon and coronoid fossa, and the size of the olecranon fossa were measured and compared between the affected and normal sides using 3D bone models to assess the distal humerus morphology.

RESULTS

The average radius of the distal humerus was smaller on the affected side than on the normal side. Furthermore, the average distance between the olecranon and coronoid fossa was greater and the average size of the olecranon fossa was smaller on the affected side than on the normal side. The size of the distal humerus was significantly smaller and the olecranon fossa was significantly shallower on the affected side.

CONCLUSIONS

Consistent with our original hypothesis, the distal humerus with flexion contracture in upper OBPP was hypoplastic. The shallow olecranon fossa might prevent full extension of the elbow even though soft tissue contracture release is performed. We recommend evaluation of the morphology of the olecranon fossa to determine the treatment plan for elbow flexion contracture with OBPP.

Relationship between glenoid deformity and gait characteristics in a rat model of neonatal brachial plexus injury

Neonatal brachial plexus injury (NBPI) results in substantial postural and functional impairments associated with underlying muscular and osseous deformities. We examined the relationship between glenoid deformity severity and gait in a rat model of NBPI, an established model for studying the in vivo pathomechanics of NBPI. At 8 weeks post-operatively, we monitored the gait of 24 rat pups who exhibited varying degrees of glenoid deformity following unilateral brachial plexus neurectomy and chemodenervation interventions administered 5 days postnatal. Five basic stride and stance metrics were calculated for the impaired forelimbs over four consecutive gait cycles. Bilateral differences in glenoid version (ΔGA_v ) and inclination (ΔGA_i ) angles were computed from data for the same rats as reported in a previous study. A linear regression model was generated for each deformity-gait pair to identify significant relationships between the two. ΔGA_v was not significantly correlated with any gait measurements, while ΔGA_i significantly correlated with all five gait measurements. Specifically, ΔGA_i was significantly positively correlated with stride length (R²  = 0.38, p = 0.001) and stance factor (R²  = 0.45, p < 0.001), and significantly negatively correlated with stance width (R²  = 0.24, p = 0.016), swing/stance ratio (R²  = 0.17, p = 0.046), and stride frequency (R²  = 0.33, p = 0.003). Rats with declined glenoids exhibited the most altered gait.

CLINICAL SIGNIFICANCE

Our findings link musculoskeletal changes and functional outcomes in an NBPI rat model. Thus, gait analysis is a potentially useful, non-invasive, quantitative way to investigate the effects of injury and deformity on limb function in the NBPI rat model. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1991-1997, 2018.