Traumatic brachial plexus injuries (BPI) are among the most challenging conditions in reconstructive surgery, particularly when shoulder function is compromised due to deltoid and supraspinatus paralysis. Restoration of shoulder abduction and external rotation plays a critical role in improving upper limb utility and patient independence. In cases where primary nerve repair fails or is not feasible, secondary muscle transfers serve as a vital salvage option. Among these, trapezius transfer has emerged as a time-tested method for restoring shoulder abduction, leveraging the preserved function of the spinal accessory nerve.

Conventional trapezius transfer (CTT), as described by multiple surgeons, often involves the transfer of a bony segment of the acromion or clavicle along with the trapezius insertion to the proximal humerus. While functionally effective, this approach necessitates extensive dissection, osteotomies, and hardware fixation, thereby increasing surgical morbidity, postoperative immobilization, and complication rates such as nonunion or infection.

Recent advancements have introduced modified techniques involving the use of tensor fascia lata (TFL) grafts to elongate the trapezius tendon and allow for a purely soft-tissue-based transfer to the deltoid insertion area. This modification, first described by Mayer, eliminates the need for bone work and may reduce operative risk, simplify the procedure, and shorten recovery time. Early reports suggest promising functional outcomes, but comprehensive, comparative evaluation of this modified technique against the conventional approach is still lacking in the literature.

Furthermore, while isolated studies have assessed surgical feasibility and immediate functional outcomes, few have incorporated patient-reported outcome measures, complication profiles, and long-term follow-up. No large-scale, direct, comparative studies have yet explored the differences in efficacy, safety, and patient satisfaction between the traditional and modified methods in a systematic, randomised manner.

Given these gaps in current knowledge and the potential benefits of the modified approach, a structured comparison is both timely and essential. This study aims to fill that void by evaluating and comparing the outcomes of conventional versus modified trapezius transfer techniques, using a randomised control trial. The findings of this study may help establish evidence-based indications for each method and guide clinical decision-making in the functional reconstruction of the shoulder in BPI.