Free functional muscle transfer for upper limb paralysis - A systematic review

Functional restoration of upper limb paralysis represents a major reconstructive challenge. Free functional muscle transfer (FFMT) enables reanimation in patients with a lack of local donor tissues or delayed presentation. This systematic review summarises the evidence for FFMT in the reconstruction of upper limb paralysis.

A comprehensive search of MEDLINE and EMBASE was performed with a systematic review using methodology adapted from the Cochrane Handbook and the PRISMA statement. Data from included studies were compiled and narratively synthesised. Studies were assessed for risk of bias.

A total of 1155 records were screened, with 39 observational studies of 904 patients included. The most common aetiology was brachial plexus injury (736, 81.4%). Mean time from injury to intervention was 26 months. Restoration of elbow flexion was the commonest reconstructive goal. The most common donor muscle was gracilis (91.5%). Reported outcomes were heterogeneous with patient-reported outcome measures (PROMs) available in only 7 of 39 studies. Nearly half of FFMTs had a post-operative MRC grade of <4 and 18.1% had an MRC <3. Mean flap failure rate was 3.6% (range 0-10.5%). All studies were at high risk of bias.

FFMT may be an effective surgical intervention for upper limb paralysis; however, the current evidence has significant shortcomings. There is no consensus regarding outcome measures nor is it possible to identify prognostic factors for its effectiveness. This review highlights a need for improved study design with pre-operative assessment, standardisation in outcome reporting, and the use of PROMs to determine the effectiveness of FFMT in upper limb paralysis.