Summary & Overview
CPT 21705: Scalenus Anticus Muscle Division with Cervical Rib Removal
CPT code 21705 denotes open surgical division of the scalenus anticus muscle with removal of a cervical rib to relieve scalenus anticus syndrome, a neurovascular compression disorder of the neck. The code captures a targeted decompression procedure that can be definitive therapy for patients with symptomatic nerve or vascular impingement due to anatomic variants. Nationally, accurate coding for this procedure matters for surgical quality measurement, payer coverage determinations, and appropriate aggregation of utilization and outcome data.
Key payers referenced in the analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. The publication provides a concise clinical context for the procedure, typical sites of service (hospital operating rooms and ambulatory surgery centers), and the procedural intent (nerve/vascular decompression). Readers will find benchmarks and coding guidance, discussion of common billing modifiers and documentation touchpoints, and a summary of policy considerations that affect coverage and payment. Where specific data elements were not supplied, the text notes that data are not available in the input. This national overview supports clinicians, coders, and policy analysts seeking clear, code-level context for 21705 without state-specific details.
Billing Code Overview
CPT code 21705 describes a surgical procedure in which the provider divides the scalenus anticus (anterior scalene) muscle on the side of the neck and removes a cervical rib. This operation is performed to treat scalenus anticus syndrome, a painful condition caused by compression of nearby nerves by the muscle and anatomic rib variant.
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Service type: Surgical procedure, open neck surgery for decompression
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Typical site of service: Hospital operating room or ambulatory surgery center
Clinical & Coding Specifications
Clinical Context
A 42-year-old right-handed female presents to a tertiary referral otolaryngology / vascular surgery clinic with a 9-month history of progressive right-sided neck and shoulder pain radiating into the ipsilateral upper extremity, paresthesia in the ulnar distribution, and positional worsening when lifting the arm. Conservative care including physical therapy, activity modification, and analgesics provided minimal relief. Examination demonstrates tenderness over the scalene muscle, positive supraclavicular provocative maneuvers, and focal neck crepitus. Imaging with cervical spine radiographs and dedicated neck CT identifies an anomalous cervical (C7) rib and hypertrophied scalenus anticus compressing the lower brachial plexus.
The clinical workflow includes preoperative evaluation with history and physical, review of imaging, informed consent discussing scalenectomy and cervical rib resection, preoperative anesthesia assessment, operative scalenus anticus muscle division and cervical rib excision under general anesthesia, immediate postoperative neurovascular assessment, and short inpatient observation or same-day discharge depending on recovery. Postoperative documentation includes operative report with laterality, estimated blood loss, complications, and any applicable modifiers for professional or facility billing. Follow-up includes wound check, physical therapy referral, and neurologic reassessment.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
LT | Left side |