Treatment of neurogenic scapular winging: a systematic review on outcomes after non-surgical management and tendon transfer surgery.

BACKGROUND: Scapular winging is a rare condition of the shoulder girdle which presents challenging treatment decisions for clinicians. To inform clinical practice, clinicians need guidance on what the best treatment decision is for their patients and such recommendations should be based on the total evidence available. Therefore, the purpose of this review was to systematically review the evidence regarding non-surgical management and tendon transfer surgery of patients with neurologic scapular winging due to serratus anterior (SA) or trapezius (TP) palsy.

METHODS: PubMed, Embase, Web of Science, Cochrane Library, Emcare and Academic Search Premier were searched up to 05/04/2022 for studies reporting on clinical outcomes after non-surgical management and tendon transfer surgery of scapular winging due to weakness of the SA or TP muscle. The ICROMS-tool was used to classify the quality of the studies. Primary outcomes were: the fraction of patients with spontaneous recovery after non-surgical management and improvement in shoulder function, pain- and shoulder scores after tendon transfer surgery. Data were pooled if data on the same outcome were available for at least three studies, using random effects meta-analysis.

RESULTS: Twenty-three(ten moderate-quality (MQ) and thirteen low-quality) studies were included. Six studies(three MQ; 234 shoulders) reported on outcomes after non-surgical management of SA palsy, while respectively twelve(six MQ; 221 shoulders) and six studies(one MQ;80 shoulders) evaluated outcomes of tendon transfer for SA- or TP palsy(one study addressed both). Spontaneous recovery of scapular winging with non-surgical management varied between 21-78% across studies after a median follow-up of 72 months. For surgical management of SA palsy, pooling data in a meta-analysis showed that patients on average improved by 47 degrees(95CI:34-61,P=<0.001) in active forward flexion, had lower VAS-scores for pain(mean difference(MD):-3.0, 95CI:-4.9- -1.0,P=0.003) and had substantial improvements in ASES(MD:24, 95CI: 9-39,P=0.002) and Constant scores(MD:45, 95CI:39-51),P=<0.001). Patients with TP palsy on average improved by 36 degrees(95CI:21-51,P=<0.001) in active forward flexion after tendon transfer. Statistical pooling was not possible for other outcome measures as insufficient data were available.

CONCLUSION: A substantial part of non-surgically managed patients with scapular winging seems to have persistent complaints, which should be part of the information provided to patients. Data pooling demonstrated significant improvements in shoulder function, pain- and shoulder scores after tendon transfer surgery, but higher quality evidence is needed to allow for more robust recommendations and guide clinical decision-making on when to perform such functional surgery.