Are tendon transfer, biceps rerouting, and one bone osteotomy medically indicated for a 9-year-old boy with birth brachial plexus palsy (Brachial Plexus Disorders, G54.0) and residual left upper extremity weakness?

Medical Necessity Determination for Surgical Intervention in Birth Brachial Plexus Palsy

Direct Recommendation

Yes, the proposed surgical procedures (tendon transfer, biceps rerouting, and forearm osteotomy) are medically indicated for this 9-year-old boy with birth brachial plexus palsy and persistent functional impairment despite conservative management.

Rationale for Medical Necessity

Conservative Treatment Optimization Met

• This patient has undergone extensive conservative management including multiple prior surgeries (neuronal resection, grafting, nerve transfers, neurolysis), Botox injections, physical therapy, and bracing over multiple years, meeting the threshold for surgical consideration.
• The documented functional limitations (inability to actively pronate/supinate, weak grasp, wrist extension with ulnar deviation, no FCU/FCR function) demonstrate persistent disability affecting activities of daily living despite maximal medical management.
• The patient's Mallet score of 20/30, Active Movement Scale scores showing multiple movements at 0-3 (severely limited), and -90 degrees active pronation deficit document objective functional impairment requiring intervention.

Specific Surgical Indications Present

Tendon Transfer (CPT 25310):

• Indicated for the documented lack of FCU/FCR function and weak grasp with reasonable finger flexion 1, 2.
• The goal is to restore wrist stability and improve hand positioning for functional activities, which the patient currently cannot perform with his left hand except for basic carrying 3.

Biceps Rerouting:

• This procedure is specifically indicated for severe supination contracture in obstetric brachial plexus palsy, with evidence showing it prevents recurrence when combined with osteotomy 1.
• The patient demonstrates fixed supination deformity (passive supination 90 degrees, active supination only 10 degrees, active pronation -90 degrees), which severely limits hand function for typing, writing, and daily activities 1, 2, 3.
• Studies demonstrate that biceps rerouting combined with forearm osteotomy improves pronation from 0 degrees to 80 degrees median at follow-up, with no recurrences reported 1.
• The biomechanical conversion of the biceps from a supinator to pronator provides active motor power for pronation, not just passive positioning 3.

Forearm Osteotomy (CPT 25350,25355,25360,25365,25370,25375):

• The documented forearm dysplasia with ulnar deviation and decreased scaphoid ossification on radiographs indicates structural deformity requiring bony realignment 1, 2.
• Sequential surgical planning of forearm osteotomy followed by biceps rerouting (or combined procedure) is the recommended approach for severe supination deformity, with recurrence rates of 20-42% for osteotomy alone reduced to 0% when combined with biceps rerouting 1, 2.
• The patient's fixed forearm position in supination/neutral without active pronation beyond weak biceps function meets criteria for one-bone forearm osteotomy to reposition the forearm in neutral or slight pronation 2.

Age-Appropriate Timing

• At 9 years old, this patient is at an optimal age for surgical intervention—old enough to cooperate with postoperative rehabilitation but young enough to benefit from remaining growth potential and neuroplasticity.
• The patient has sufficient remaining growth (approximately 5-7 years until skeletal maturity) to allow for adaptive remodeling and functional improvement 2.

Functional Goals Achievable

• The documented ability to "flop his left wrist" and use the hand for carrying indicates some preserved function that can be optimized with surgical reconstruction.
• The patient's participation in sports (baseball, flag football) demonstrates motivation and activity level that would benefit from improved upper extremity function.
• Repositioning the forearm in a more pronated position improves the use of the extremity in activities of daily living, particularly for keyboard typing and writing, which this patient currently cannot perform with his left hand 2.

Important Caveats and Considerations

Surgical Complexity and Risks

• These procedures carry significant complication risks in the pediatric population, though the specific combination of tendon transfer, biceps rerouting, and osteotomy has demonstrated favorable outcomes in published case series 1, 2, 3.
• The surgeon should have expertise in pediatric brachial plexus reconstruction and metabolic bone disease management to optimize outcomes.
• Postoperative serial casting for elbow flexion contracture management will be required after forearm stabilization, as documented in the surgical plan.

Staged vs. Combined Approach

• The evidence supports both staged procedures (osteotomy first, then biceps rerouting if pronation remains <50 degrees) and combined single-stage procedures 1, 2.
• Given this patient's severe deficits (-90 degrees active pronation), a combined approach may be justified to minimize total surgical episodes and recovery time 2, 3.

Expected Outcomes

• Median passive pronation improvement from 0 degrees to 80 degrees can be expected based on published outcomes 1.
• Active pronation and wrist extension typically improve significantly, with median wrist extension improving from -30 degrees to 45 degrees 1.
• No recurrences were reported in the biceps rerouting studies at median 6.8 years follow-up, compared to 20-42% recurrence with osteotomy alone 1.

Postoperative Management Requirements

• Extended immobilization and serial casting will be necessary.
• Intensive occupational therapy focusing on motor re-education for the rerouted biceps function.
• Regular follow-up with functional assessments using standardized scores (Mallet, Active Movement Scale, Toronto Score) to document improvement.