CPT Code Overview

CPT 64643 describes destruction by neurolytic agent (e.g., chemical, thermal, electrical, or radiofrequency) procedures on the somatic nerves. This procedure is used to interrupt somatic nerve function to relieve refractory pain or spasticity related to neuromuscular conditions. The service falls under the Neurology service type and is most commonly performed in the office (POS 11) setting.

Clinical Context

A typical patient is an adult referred to a neurology or pain medicine clinic for focal, refractory muscle hyperactivity causing pain, functional impairment, or postural deformity (for example, a patient with spasmodic torticollis). The patient undergoes evaluation including history, focused neurologic and musculoskeletal exam, and review of prior conservative therapies. After confirming a target somatic nerve or nerve plexus responsible for the symptomatic muscle group and obtaining informed consent, the procedure is scheduled in the office (POS 11). On the day of service the clinician performs an aseptic technique, identifies the target using anatomic landmarks and optionally electrodiagnostic guidance, and administers a neurolytic agent (chemical, thermal, electrical or radiofrequency) to destroy or denervate the somatic nerve supply to the involved muscles. The patient is monitored for immediate adverse effects, given post-procedure instructions, and scheduled for follow-up to assess efficacy and complications.

Coding Specifications

• Modifier 50 (Bilateral Procedure): Use when the neurolytic procedure is performed bilaterally during the same session and payer guidelines permit bilateral reporting.

• Modifier LT (Left Side): Use to indicate the procedure was performed on the left side when laterality is required by the payer.

• Modifier RT (Right Side): Use to indicate the procedure was performed on the right side when laterality is required by the payer.

• Modifier 59 (Distinct Procedural Service): Use when the neurolytic procedure is separate and distinct from other services performed on the same day (for example, when another injectable or diagnostic procedure is performed in a different anatomical site) and documentation supports distinctness.

Provider Taxonomies

| Taxonomy Code | Specialty |---|---| | 2084N0400X | Neurology Physician | | 2081P2900X | Physical Medicine & Rehabilitation Physician | | 2084P0800X | Pain Medicine Physician | | 2084D0003X | Neuromuscular Medicine Physician | | 2084P0015X | Neurodevelopmental Disabilities Physician |

• Neurology Physician (2084N0400X): Specialist in neurologic diagnoses contributing to focal spasticity or dystonia.

• Physical Medicine & Rehabilitation Physician (2081P2900X): Specialist in functional impairment and rehabilitation planning related to muscle hyperactivity.

• Pain Medicine Physician (2084P0800X): Specialist in interventional pain procedures and neurolytic techniques.

• Neuromuscular Medicine Physician (2084D0003X): Specialist in disorders of the peripheral nervous system and neuromuscular junction.

• Neurodevelopmental Disabilities Physician (2084P0015X): Specialist in complex neurodevelopmental conditions where focal denervation may be considered.

Related Diagnoses

• G24.3 — Spasmodic torticollis

  Clinical relevance: Spasmodic torticollis is a focal dystonia of neck muscles; somatic nerve neurolytic procedures can target affected nerves to reduce involuntary contractions and pain.

• G82.50 — Quadriplegia, unspecified

  Clinical relevance: Patients with quadriplegia may develop focal spasticity or muscle overactivity in specific muscle groups where targeted somatic nerve neurolysis is considered to improve positioning or reduce pain.

• G80.9 — Cerebral palsy, unspecified

  Clinical relevance: Cerebral palsy commonly involves spasticity and muscle contractures; selective neurolytic procedures on somatic nerves may be used for focal management of spastic muscles.

• M62.838 — Other muscle spasm

  Clinical relevance: Localized muscle spasms causing pain or functional limitation can be addressed by neurolytic denervation of the supplying somatic nerves.

• G24.02 — Drug induced acute dystonia

  Clinical relevance: Acute dystonic reactions affecting focal muscle groups may be treated acutely with medications but in refractory or chronic cases targeted neurolytic procedures could be considered for focal symptom control.

Related CPT Codes

| CPT Code | Description |---|---| | 64642 | Chemodenervation of one extremity; 5 or more muscles | | 64644 | Chemodenervation of trunk muscle(s); 1-5 muscle(s) | | 64645 | Chemodenervation of trunk muscle(s); 6 or more muscles | | 95874 | Needle electromyography for guidance in conjunction with chemodenervation | | 95875 | Ischemic limb exercise test with needle electromyography |

• 64642: Used for chemodenervation of an extremity involving five or more muscles; may be an alternative when chemical denervation targets muscle groups rather than specific somatic nerves.

• 64644: Used for chemodenervation of trunk muscles (1–5 muscles); can be used in workflows where trunk muscle groups are treated chemically instead of or in addition to somatic nerve neurolysis.

• 64645: Used for chemodenervation of trunk muscles when six or more muscles are treated; relates as an alternative treatment approach for broader trunk involvement.

• 95874: Performed when needle electromyography is used to guide chemodenervation or neurolytic targeting; commonly performed on the same day to improve accuracy of nerve or muscle localization.

• 95875: Performed when ischemic limb exercise testing with needle EMG is needed in conjunction with neuromuscular evaluation; less commonly paired but may appear in comprehensive electrodiagnostic assessment.

• Commonly used together or as alternatives: 95874 is commonly used together with the primary neurolytic procedure for procedural guidance. The chemodenervation codes (64642, 64644, 64645) represent alternative or complementary approaches depending on the target (extremity vs trunk) and number of muscles treated.

National commercial mean rates for 64643 are higher than Medicare. The mean for Medicare is $102.42 versus the BUCA (average commercial) mean of $122.48, indicating commercial payers generally reimburse above the Medicare mean for this code. UnitedHealth Group and Cigna exhibit the highest national mean rates at $155.87 and $145.59 respectively.

Rate dispersion measured as the difference between the 75th and 25th percentiles varies across payers. Medicare is the tightest with a spread of $10.00 (P75 $107.00 minus P25 $97.00). Aetna and BCBS show moderate dispersion at $50.25 and $55.85 respectively. UnitedHealth Group and Cigna show the widest spreads at $87.33 and $78.50 respectively, indicating greater variability in negotiated allowed amounts. The table and chart below present the full percentile and mean breakdown for each payer.