Outcomes of Shoulder Functions in Spinal Accessory to Suprascapular Nerve Transfer in Brachial Plexus Injury: A Comparison between Anterior and Posterior Approach

Anterior vs. posterior approach for spinal accessory nerve transfer to suprascapular nerve in brachial plexus injury: a systematic review and meta-analysis of comparative studies

Spinal accessory nerve (SAN) to suprascapular nerve (SSN) transfer is an effective surgical option for traumatic brachial plexus injuries (BPIs) when nerve grafting is not applicable. It is performed via two approaches: anterior and posterior. Despite the theoretical advantages of the posterior approach, clinical trials have yielded variable outcomes. This study aimed to compare the outcomes of anterior and posterior approaches for SAN to SSN transfer in restoring the Range of motion (ROM) and strength of shoulder abduction and external rotation in BPIs. We searched PubMed, Embase, Cochrane Library, Scopus, and Web of Science to identify studies comparing anterior and posterior approaches for SAN to SSN transfer. Quality assessment was performed using the Cochrane RoB2 tool and Newcastle-Ottawa Scale. via RevMan 5.4, meta-analyses were conducted. We identified eight comparative studies with 311 patients (n = 140 for posterior transfer, n = 171 for anterior transfer). Both approaches showed comparable outcomes with statistically significant advantages to the posterior approach by a modest but meaningful difference in shoulder abduction ROM (MD: 8.98°, 95% CI: 1.19 to 16.78, P = 0.02, I² = 0%) and in the Modified Medical Research Council (MRC), The posterior approach was associated with 4.78 times higher odds of achieving a grade ≥ M3 on the MRC scale (OR: 4.78, 95% CI: 1.43 to 15.96, P = 0.01, I² = 0%). We suggest that when functional gains are a priority, surgeons consider the posterior approach while still accounting for patient/surgeon specific factors and injury details.

Results of spinal accessory nerve to suprascapular nerve transfers in children with brachial plexus birth injury

Shoulder external rotation after brachial plexus birth injury can be restored by transfer of the spinal accessory nerve to the suprascapular nerve, or more distally to its infraspinatus branch. We studied the outcome of these nerve transfers in 52 patients with a minimum postoperative follow-up of 12 months (mean 7.3 years). The median postoperative improvement in shoulder external rotation was 120° (interquartile range [IQR] 45-135) after anterior and 110° (IQR 83-120) after dorsal spinal accessory nerve transfer to the suprascapular nerve main trunk, and 110° (IQR 80-125) after transfer to the infraspinatus branch. Patients operated after 20 months obtained external rotation ≥90° less frequently. The results of this study suggest that a decision about distal nerve transfer for shoulder external rotation is recommended at 1.5 years of age.Level of evidence: III.

Prevalence of Concomitant Distal Suprascapular Nerve Injury in Patients with Root-Level Brachial Plexus Palsy: A Clinical Anatomic Study of Injury Pattern

BACKGROUND

Root-level suprascapular nerve palsy is commonly reconstructed by means of spinal accessory nerve transfer in brachial plexus injury, but some patients do not recover. The authors hypothesize that this relates to concomitant undetected lesions distal to the nerve transfer coaptation.

METHODS

A total of 67 patients with plexus injury and C5/C6 root involvement were included in this prospective study between March of 2021 and October of 2022. During spinal accessory to suprascapular nerve transfer, the entire suprascapular nerve was explored using cresenteric clavicular osteotomy, and anatomic variations and injury patterns categorized.

RESULTS

Proximal root involvement was C5 to C6 ( n = 8), C5 to C7 ( n = 13), C5 to C8 ( n = 17), or C5 to T1 ( n = 29). Mean time from injury to surgery was 5.6 months. The suprascapular nerve was found to be injured in 16 of 67 cases (24%). In 9 cases (13%), the lesion was proximal to the suprascapular fossa. In 3 cases (4%), the suprascapular nerve was injured both proximally and within the fossa, and in 4 cases (6%), in the fossa or distal to it. Therefore, in 7 cases (10%), a traditional suprascapular nerve transfer would not successfully bypass the zone of injury of the suprascapular nerve in the fossa. Of the 16 cases of concomitant suprascapular nerve injury, 1 of 8 in occurred in C5 to C6 root injury, 4 of 13 of C5 to C7 root injury, 5 of 17 of C5 to C8 root injury, and 6 of 39 in total paralysis.

CONCLUSIONS

Concomitant distal suprascapular nerve injury in brachial plexus stretch palsy occurred in 24% of the cases. This warrants attention from the surgeon to identify distal lesions and to perform the nerve transfer beyond any secondary lesions.

Preoperative ultrasound mapping of the suprascapular and spinal accessory nerves: A surgeon's guide to precision

BACKGROUND

The aim of the study was to evaluate the accessibility and localization of spinal accessory and suprascapular nerves in the suprascapular region in healthy volunteers using ultrasonography.

METHODS

One hundred healthy volunteers were included and the location of the spinal accessory nerve (SAN) and suprascapular nerve (SSN) was assessed in the right suprascapular region.

FINDINGS

Seventy men and 30 women, (mean age 40.37 years; mean BMI 23.44 kg/m2) participated in the study. Mean distance of SAN from the vertebral spinous process and medial border of the scapula was 3.80 and 0.7 cm, respectively. Mean depth of SAN from the skin was 2.67 cm. The mean distance of SSN from the spine was 7 cm and mean depth of SSN from the skin was 3.28 cm. In overweight and obese individuals, the distance of SAN from the skin and vertebral spinous process and distance of SSN from the vertebral spine increased significantly. According to gender, there was no statistically significant difference in the location of SSN and SAN; however, the distance of SSN from the vertebral spine was significantly increased with increasing age.

INTERPRETATION

The SSN and SAN in the suprascapular region can be consistently and reliably mapped using ultrasound. These data can also help in surface markings of both the nerves, which reduces the operating time and risk of iatrogenic injury.

Spinal Accessory to Suprascapular Nerve Transfer in Traumatic Brachial Plexus Injury: A Comparative Study of Shoulder Recovery Outcomes in the Anterior versus Posterior Approach and Surgeons' Preference

BACKGROUND

Conventionally, neural transfer of the spinal accessory nerve to the suprascapular nerve for shoulder abduction in traumatic brachial plexus injury is performed via the anterior approach. However, important advantages of the posterior approach have made it an alternative option, such as the proximity of neural coaptation to the muscle to be reinnervated and negating the effects of a second injury to the suprascapular nerve.

METHODS

Retrospective data was collected from 30 patients with brachial plexus injury who underwent spinal accessory nerve to suprascapular nerve transfer over 4 years. There were 15 patients in the anterior-approach group (group A) and 15 in the posterior-approach group (group B). Functional outcome at the shoulder was measured as muscle power and active range of motion at 18 months, and data on patients' satisfaction levels and surgeons' perceptions was also collected.

RESULTS

No statistical difference was found in the muscle strength achieved in the 2 groups (P = 0.34), but significant recovery was found in the external rotation achieved by group B (P = 0.02). Statistical difference was insignificant in the 2 groups' active range of motion during abduction and external rotation. The satisfaction index of patients was 86.7% in group B as compared to 68% in group A. Surgeons' perspective showed a faster speed of suprascapular nerve exploration in the posterior approach, with better visibility of supraspinatus muscle contraction, and overall surgeons preferred the posterior approach.

CONCLUSIONS

External rotation at the shoulder is better via the posterior approach, but no difference in abduction was noted. Patients who underwent the posterior approach were more satisfied with the recovery, and surgeons preferred the posterior approach.

A Randomised Control Trial Comparing the Outcomes of Anterior with Posterior Approach for Transfer of Spinal Accessory Nerve to Suprascapular Nerve in Brachial Plexus Injuries

Background: In brachial plexus surgery, a key focus is restoring shoulder abduction through spinal accessory nerve (SAN) to suprascapular nerve (SSN) transfer using either the anterior or posterior approach. However, no published randomised control trials have directly compared their outcomes to date. Therefore, our study aims to assess motor outcomes for both approaches. Methods: This study comprises two groups of patients. Group A: anterior approach (29 patients), Group B: Posterior approach (29 patients). Patients were allocated to both groups using selective randomisation with the sealed envelope technique. Functional outcome was assessed by grading the muscle power of shoulder abductors using the British Medical Research Council (MRC) scale. Results: Five patients who were operated on by posterior approach had ossified superior transverse suprascapular ligament. In these cases, the approach was changed from posterior to anterior to avoid injury to SSN. Due to this reason, the treatment analysis was done considering the distribution as: Group A: 34, Group B: 24. The mean duration of appearance of first clinical sign of shoulder abduction was 8.16 months in Group A, whereas in Group B, it was 6.85 months, which was significantly earlier (p < 0.05). At the 18-month follow-up, both intention-to-treat analysis and as-treated analysis were performed, and there was no statistical difference in the outcome of shoulder abduction between the approaches for SAN to SSN nerve transfer. Conclusions: Our study found no significant difference in the restoration of shoulder abduction power between both approaches; therefore, either approach can be used for patients presenting early for surgery. Since the appearance of first clinical sign of recovery is earlier in posterior approach, therefore, it can be preferred for cases presenting at a later stage. Also, the choice of approach is guided on a case to case basis depending on clavicular fractures and surgeon preference to the approach. Level of Evidence: Level II (Therapeutic).

Comparison of Anterior vs. Dorsal Approach for Spinal Accessory to Suprascapular Nerve Transfer in Patients With a Brachial Plexus Injury and Its Outcome on Shoulder Function

Background

Brachial plexus injuries are frequently encountered in the domain of plastic surgery, mostly secondary to road traffic accidents, gunshot injuries, or falls from a height. Many modalities have been described in the management, depending on the level and duration of the injury. C5, C6 and C5, C6, C7 are two common patterns in which nerve repair and transfers are described. At our center, we practice spinal accessory to suprascapular nerve transfer in all patients with upper trunk brachial plexus injury. There are two described approaches for the spinal accessory nerve to suprascapular nerve transfer, i.e. anterior or dorsal. The rationale for doing the posterior approach is that this approach avoids damaging the suprascapular nerve at its entrance in the suprascapular notch under the suprascapular ligament during exploration due to traction.

Materials and methods

This is a retrospective study with a consecutive sampling of 23 patients presenting at Liaquat National Hospital, Karachi, with upper trunk brachial plexus injuries during the time period from January 2016 to December 2017, i.e. two years. We divided these 23 patients into two groups, one with the anterior approach and the other with a dorsal approach for spinal accessory to suprascapular nerve transfer for shoulder abduction. The mean duration of post-surgical follow-up was from 18 to 24 months and recovery and functional outcomes were assessed.

Results

Out of the 23 patients that were included, 10 patients were operated on with an anterior approach and 13 with a posterior approach. Fifty percent (50%) of patients operated with the anterior approach and 84% of patients with the posterior showed the best motor grade recovery of M4, respectively, with better performance in patients with the posterior approach as compared to the anterior approach.

Conclusion

We advocate taking a posterior approach for spinal accessory to suprascapular nerve transfer for shoulder abduction, as it has shown better results with reliable outcomes concerning shoulder abduction, angle of abduction, and range of motion.