This study is a prospective single-arm surgical protocol evaluating biceps-to-flexor digitorum superficialis (FDS) tendon transfer using a tensor fascia lata graft for restoration of finger flexion in patients with traumatic pan-brachial plexus injury (pan-BPI). Finger flexion reconstruction in intrinsic-minus hands remains challenging, as conventional flexor digitorum profundus (FDP)-based reconstructions may result in clawing and ineffective grasp. The proposed technique aims to improve metacarpophalangeal and proximal interphalangeal joint flexion to enhance functional grasp. Eligible patients are those with pan-BPI who previously underwent nerve transfer and achieved elbow flexion strength of at least Medical Research Council (MRC) grade 4. Patients with significant joint stiffness, severe forearm soft tissue injury, or insufficient elbow flexion strength are excluded. The procedure consists of staged reconstruction followed by tendon transfer with tensor fascia lata graft interposition. Postoperative management includes 4 weeks of immobilization and progressive rehabilitation. The primary outcome is functional finger flexion, while secondary outcomes include complications and reoperation rates.