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.
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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 | Use when the procedure is performed on the left side of the neck |
RT | Right side | Use when the procedure is performed on the right side of the neck |
50 | Bilateral procedure | Use when bilateral scalenus anticus and cervical rib resections are performed during the same operative session |
62 | Two surgeons | Use when two surgeons of different specialties perform distinct portions of the procedure (e.g., vascular surgeon + thoracic surgeon) |
80 | Assistant surgeon | Use when a surgical assistant is documented and billing separately for assisting surgeon services |
81 | Minimum assistant surgeon | Use when a minimum assistant surgeon is documented (per payer policy) |
22 | Increased procedural services | Use when work required is substantially greater than typical (must be well-documented) |
52 | Reduced services | Use when a portion of the procedure is not performed or is aborted prior to completion |
53 | Discontinued procedure | Use when the procedure is started but terminated for patient-related or intraoperative reasons |
26 | Professional component | Use when reporting only the surgeon’s professional component separate from facility technical component (rare for operative codes) |
76 | Repeat procedure by same physician | Data not available in the input. |
77 | Repeat procedure by another physician | Data not available in the input. |
79 | Unrelated procedure by same physician during postoperative period | Use when an unrelated procedure is performed during global period (must be distinct and unrelated) |
58 | Staged or related procedure by same physician during postoperative period | Data not available in the input. |
| Taxonomy Code | Specialty | Notes |
|---|---|---|
2080S0400X | Otolaryngology (ENT) | Otolaryngologists perform neck and brachial plexus-related procedures and may address scalene contributions to nerve compression |
207RX0400X | General Surgery | General surgeons with head & neck or thoracic experience may perform cervical rib resections and scalenectomies |
2084P0200X | Vascular Surgery | Vascular surgeons manage neurovascular compression syndromes involving the thoracic outlet and cervical rib resections |
2084T0100X | Thoracic Surgery | Thoracic surgeons may perform cervical rib resections when thoracic outlet anatomy is complex |
2087S0100X | Neurological Surgery | Neurosurgeons consult or operate when brachial plexus or cervical spine pathology coexists |
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
M54.2 | Cervicalgia | Neck pain commonly associated with scalene muscle pathology and thoracic outlet symptoms |
G54.0 | Brachial plexus disorders | Describes neuropathic symptoms from brachial plexus compression by scalene muscles or cervical rib |
M25.50 | Pain in unspecified joint of upper limb | Reflects referred pain into the shoulder/arm seen with scalenus anticus syndrome |
M54.12 | Radiculopathy, cervical region | Cervical radiculopathy may coexist and requires differentiation from brachial plexus compression |
M54.6 | Pain in thoracic spine | Referred or regional pain associated with postural or muscular contributors to thoracic outlet symptoms |
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
21470 | Excision of cervical rib | Often performed alone or in conjunction with scalenus anticus division when a cervical rib is present; directly addresses bony contribution to thoracic outlet syndrome |
64585 | Neuroplasty and/or transposition; brachial plexus | May be performed when brachial plexus neurolysis or transposition is required in addition to scalenectomy |
62287 | Decompression procedure, cervical nerve root | Performed when concomitant cervical radiculopathy requires direct cervical decompression in the same operative setting |
36415 | Collection of venous blood by venipuncture | Common preoperative laboratory procedure performed in the perioperative workflow |
99223 | Initial hospital care, per day, for the evaluation and management of a patient | Used for higher complexity preoperative or postoperative inpatient E/M services related to the surgical admission |