Ideas and InnovatIons

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4 Color Fig(s): F1-3

Art: PRSJ-D-15-00550

Ideas and Innovations

Selective Neurotization of the Infraspinatus Muscle in Brachial Plexus Birth Injury Patients Using the Accessory Nerve Antti J. Sommarhem, M.D., Ph.D. Petra M. Grahn, M.D. Yrjänä A. Nietosvaara, M.D., Ph.D. Helsinki, Finland

Summary: The authors present a new technique to improve active shoulder external rotation in patients with brachial plexus birth injury. Eight brachial plexus birth injury patients (aged 1.5 to 4.7 years) lacking active external rotation in adduction (45 degrees) underwent neurotization of the infraspinatus branch of the suprascapular nerve with the spinal accessory nerve. Active and passive range of shoulder motion was measured postoperatively (3, 6, and 12 months). Parents’ satisfaction was assessed. At 1-year follow-up, mean improvement for active external rotation was 47 degrees (range, 20 to 85 degrees) in adduction and 49 degrees (range, 5 to 85 degrees) in abduction. All but one patient’s parents were satisfied. Functionally significant active external rotation can be restored in brachial plexus birth injury by direct neurotization of the infraspinatus muscle. (Plast. Reconstr. Surg. 136: 00, 2015.) CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

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rachial plexus birth injury occurs in one to four per 1000 births.1–3 Most injuries are temporary and recover during the first year of life. The risk for a permanent injury in Helsinki is 0.06 percent.3 Shoulder function, especially external rotation, is affected in nearly all permanent injuries, and posterior subluxation of the glenohumeral joint develops in one-third of these patients during the first year of life.3–5 In congruent glenohumeral joints, limited external rotation is initially treated by passive external rotation exercises, botulinum toxin injections, and different soft-tissue releases.6–8 However, active external rotation cannot be improved by these measures if the infraspinatus function does not recover. In this setting, active external rotation has been reported to be improved by tendon transfers and more recently by neurotizing the suprascapular nerve proximal to the supraspinatus branch using the spinal accessory nerve.8–10 We describe a new technique to

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From the Department of Surgery, Children’s Hospital; and the Department of Hand Surgery, Helsinki University Central Hospital. Received for publication May 5, 2015; accepted June 18, 2015. Presented at Techniques in Brachial Plexus, in Paris, France, April 17 through 18, 2015. Copyright © 2015 by the American Society of Plastic Surgeons DOI: 10.1097/PRS.0000000000001761

selectively neurotize the infraspinatus muscle without risk of losing any abduction in patients with congruent glenohumeral joints without contractures but above horizontal active abduction.

PATIENTS AND METHODS This study consists of eight consecutive patients identified between 2012 and 2014, with active external rotation in adduction of less than 10 degrees. All patients had congruent shoulders without internal rotation contracture and active shoulder elevation above 100 degrees. Two patients had a winging scapula. Selective neurotization of the infraspinatus muscle was performed after informed consent at a mean age of 2.9 years. Six patients had received botulinum toxin injections and one patient had undergone arthroscopic subscapular tenotomy before the neurotization. Range of motion was measured preoperatively and postoperatively by two independent observers (a physiotherapist and an occupational therapist) with a goniometer (Table 1). The minimum delay between botulinum toxin treatment and preoperative assessment was 4 months (mean, 13 Disclosure: The authors have no financial interest to declare in relation to the content of this article. No funds supporting the work were received.

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Copyright © 2015 American Society of Plastic Surgeons. Unauthorized reproduction of this article is prohibited.

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Plastic and Reconstructive Surgery • December 2015 Table 1. Patient Demographics at the Time of Surgery and Results at 1-Year Follow-Up Range of External Rotation in Adduction Patient 1 2 3 4 5 6 7 8

Passive (degrees)

Active (degrees)

Age at Botulinum Toxin (mo)

Age at Surgery (mo)

Preoperative

Postoperative

Preoperative

Postoperative

17 44

19 50 43 19 57 51 18 18

60 40 45 80 70 50 60 80

60 30 80 80 65 90 80 80

−20 −20 −15 0 0 0 0 7

45 0 70 45 60 30 45 35

2 8* 3 5

*Arthroscopic subscapular release.

months). Follow-up was performed at 3, 6, and 12 months. The number of patients is currently too small for statistical analysis.

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Surgical Technique With the patient in the prone position, a transverse skin incision at the scapular spine is made. The trapezius muscle is detached from its attachment to the scapular spine. The spinal accessory nerve is identified slightly medial to the medial margin of the scapula dorsal to the deep trapezius fascia. Its function is verified with a nerve stimulator (VariStim III nerve locator; Medtronic, Minneapolis, Minn.). The spinal accessory nerve is dissected both distally and proximally, preserving as many proximal branches to the trapezius muscle as possible. The infraspinatus muscle is detached from the scapular spine, and a layer between the scapula and the lower

infraspinatus fascia is developed. The infraspinatus branch of the suprascapular nerve can be identified next to the suprascapular artery at the glenoid notch. It is helpful to elevate the scapula with a bone hook and turn the shoulder in external rotation. Contractility of the infraspinatus muscle is assessed with electrical stimulation (0.5, 1, and 2 mA). The infraspinatus branch of the suprascapular nerve is transected at the glenoid notch, with the spinal accessory nerve as distal as necessary for it to reach the anastomosis site. Neurorrhaphy is performed with two 10-0 Ethilon sutures (Ethicon, Inc., Somerville, N.J.) and Evicel fibrin glue (Ethicon). The shoulder is worked through its full range of motion to assess the anastomosis before glue is applied. Infraspinatus and trapezius muscles are reinserted with 3-0 Vicryl sutures (Ethicon), avoiding compression on the spinal accessory nerve at the scapular spine. Postoperative immobilization is not needed (Fig. 1).

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Fig. 1. Schematic drawing of spinal accessory nerve transfer to the infraspinatus branch of the suprascapular nerve.

2 Copyright © 2015 American Society of Plastic Surgeons. Unauthorized reproduction of this article is prohibited.

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Volume 136, Number 6 • Brachial Plexus Birth Injury

Fig. 2. Mean improvement of external rotation in adduction and abduction at 1-year follow-up.

RESULTS

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At 1-year follow-up, active external rotation was improved in all patients, with the mean improvement being 47 degrees (range, 20 to 85 degrees) in adduction (Fig. 2) and 49 degrees (range, 5 to 85 degrees) in abduction. Mean improvement in passive external rotation in adduction was 10 degrees (range, −10 to 40 degrees), and that in active abduction was 16 degrees (range, 0 to 60 degrees). Patient age at the time of surgery did not affect the outcome (Fig. 3). Winging of the scapula disappeared in one patient but developed in three patients after the operation. The winging did not affect shoulder motion. In four patients, hypertrophic scars were treated with silicone sheets. All but one patient’s parents were satisfied with the result and saw the scar as a cosmetic problem.

DISCUSSION Above neutral external rotation of the shoulder is required to perform basic activities of daily

living well.11–13 Active external rotation is poor without adequate infraspinatus function, which can be improved by different tendon transfers.8,14,15 Infraspinatus function can be restored by neurotizing the suprascapular nerve, which can be performed at an earlier age than tendon transfers.9,10 In brachial plexus birth injury patients older than 1.5 years with no active shoulder external rotation in adduction, the likelihood of spontaneous infraspinatus recovery is very small (Paavilainen et al., unpublished results). Selective neurotization of the infraspinatus branch of the suprascapular nerve can thus be offered to improve active external rotation in children that are aged 1.5 years or older. The upper age limit is not known, but the oldest patient in our series benefited from the procedure at 5.5 years of age. Furthermore, there was no difference in results between children younger than 2 and older than 2 years at the time of surgery.

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Fig. 3. Active external rotation in adduction. Postoperative results as a result of time (months) since surgery.


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Plastic and Reconstructive Surgery • December 2015 The downsides of the presented technique in some patients include winging of the scapula, the long-term effects of which are unknown, and hypertrophic scarring developing after surgery. These adverse effects should be discussed with the parents before deciding to proceed with surgery. In addition, lower trapezius transfer to improve shoulder external rotation is not possible should the neurotization fail. Clinically significant active external shoulder rotation can be restored in brachial plexus birth injury by direct neurotization of the infraspinatus muscle. Petra M. Grahn, M.D. Merenneidontie 26E 02320 Espoo, Finland [email protected]

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references

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1. Foad SL, Mehlman CT, Ying J. The epidemiology of neonatal brachial plexus palsy in the United States. J Bone Joint Surg Am. 2008;90:1258–1264. 2. Hoeksma AF, Wolf H, Oei SL. Obstetrical brachial plexus injuries: Incidence, natural course and shoulder contracture. Clin Rehabil. 2000;14:523–526. 3. Pöyhiä T. Magnetic Resonance Imaging and Ultrasonography in Brachial Plexus Birth Palsy. Helsinki: University of Helsinki, Faculty of Medicine; 2011. 4. Nikolaou S, Peterson E, Kim A, Wylie C, Cornwall R. Impaired growth of denervated muscle contributes to contracture formation following neonatal brachial plexus injury. J Bone Joint Surg Am. 2011;93:461–470. 5. Li Z, Ma J, Apel P, Carlson CS, Smith TL, Koman LA. Brachial plexus birth palsy-associated shoulder deformity: A rat model study. J Hand Surg Am. 2008;33:308–312.

6. Michaud LJ, Louden EJ, Lippert WC, Allgier AJ, Foad SL, Mehlman CT. Use of botulinum toxin type A in the management of neonatal brachial plexus palsy. PM R. 2014;6:1107–1119. 7. Ezaki M, Malungpaishrope K, Harrison R, Mills J, Oishi S, Delgado M. OnabotulinumtoxinA injection as an adjunct in the treatment of posterior shoulder subluxation in neonatal brachial plexus palsy. J Bone Joint Surg Am. 2010;29:2171–2177. 8. Pearl ML, Edgerton BW, Kazimiroff PA, Burchette RJ, Wong K. Arthroscopic release and latissimus dorsi transfer for shoulder internal rotation contractures and glenohumeral deformity secondary to brachial plexus birth palsy. J Bone Joint Surg Am. 2006;88:564–574. 9. Bahm J, Noaman H, Becker M. The dorsal approach to the suprascapular nerve in neuromuscular reanimation for obstetric brachial plexus lesions. Plast Reconstr Surg. 2005;115:240–244. 10. Grossman JA, Di Taranto P, Alfonso D, Ramos LE, Price AE. Shoulder function following partial spinal accessory nerve transfer for brachial plexus birth injury. J Plast Reconstr Aesthet Surg. 2006;59:373–375. 11. Raiss P, Rettig O, Wolf S, Loew M, Kasten P. Range of motion of shoulder and elbow in activities of daily life in 3D motion analysis (in German). Z Orthop Unfall. 2007;145:493–498. 12. Langer JS, Sueoka SS, Wang AA. The importance of shoulder external rotation in activities of daily living: Improving outcomes in traumatic brachial plexus palsy. J Hand Surg Am. 2012;37:1430–1436. 13. van Andel CJ, Wolterbeek N, Doorenbosch CA, Veeger DH, Harlaar J. Complete 3D kinematics of upper extremity functional tasks. Gait Posture 2008;27:120–127. 14. Ozben H, Atalar AC, Bilsel K, Demirhan M. Transfer of latissimus dorsi and teres major tendons without subscapularis release for the treatment of obstetrical brachial plexus palsy sequela. J Shoulder Elbow Surg. 2011;20:1265–1274. 15. Elhassan B. Lower trapezius transfer for shoulder external rotation in patients with paralytic shoulder. J Hand Surg Am. 2014; 39:556–562.


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