Summary & Overview

CPT 67346: Extraocular Muscle Biopsy for Pathologic Evaluation

CPT code 67346 represents a targeted surgical biopsy of extraocular muscle tissue sent for pathological evaluation. This code captures a focused diagnostic surgical service used in ophthalmology and oculoplastic practices to investigate suspected muscular pathology affecting ocular motility or periocular disease. Nationally, accurate coding for precise biopsy procedures helps ensure clinical documentation aligns with surgical intent and supports appropriate payment and quality measurement.

Key payers in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise clinical context for when the procedure is used, guidance on typical sites of service, and an overview of common modifiers associated with surgical services. The publication outlines benchmarks for utilization and reimbursement drivers where available, highlights relevant policy considerations for coverage and medical necessity determinations, and summarizes coding nuances that can affect claim adjudication.

This resource is intended for clinical coders, revenue cycle professionals, and policy analysts seeking a national-level briefing on CPT code 67346, its clinical role, and the payer landscape that most often adjudicates these claims. Data not available in the input is clearly noted where applicable.

AetnaBlue Cross Blue ShieldCigna HealthUnitedHealthcareMedicare67346CPTextraocular musclebiopsyophthalmologysurgical-procedurepathologyoutpatient-surgery

Billing Code Overview

CPT code 67346 describes a surgical biopsy of extraocular muscle tissue in which the provider removes a very small portion of the muscle and sends it to a laboratory for pathological evaluation. The service type is a minor operative tissue biopsy of an extraocular muscle. The typical site of service is an outpatient surgical setting, commonly performed in an ambulatory surgery center or hospital outpatient department.

Clinical & Coding Specifications

Clinical Context

A typical patient is a 45–70-year-old adult referred to an ophthalmologist or oculoplastic surgeon for evaluation of chronic diplopia, suspected myogenic or neurogenic extraocular muscle disease, or an unexplained strabismus with progressive symptoms. The patient presents with a history of ocular misalignment, restricted ocular motility, pain or localized swelling near an extraocular muscle, or prior imaging showing focal muscle enlargement. Preoperative workup includes ophthalmic examination, ocular motility testing, targeted imaging (orbital CT or MRI) when indicated, and discussion of risks and purpose of the procedure: obtaining a small muscle biopsy for histopathologic and microbiologic analysis.

On the day of service the patient is consented, prepped, and administered local or general anesthesia per surgeon and anesthesiologist decision. The surgeon isolates the targeted extraocular muscle via a standard conjunctival approach, obtains a limited intramuscular tissue specimen (biopsy), achieves hemostasis, and closes the conjunctiva. The specimen is submitted to the pathology laboratory for microscopic evaluation, immunohistochemistry, and culture as indicated. Typical site of service is an ambulatory surgery center or hospital outpatient department; in some cases, a procedure may be performed in a hospital operating room when combined with other intraocular or orbital surgeries.

Specimen handling, documentation of muscle sampled, laterality, operative note describing technique and amount of tissue, and the pathology report are required components of the clinical record. Billing uses 67346 for extraocular muscle biopsy with appropriate modifier to indicate professional, bilateral, or other circumstances when applicable.

Coding Specifications

Modifier	Description	When to Use
`26`	Professional component	When billing only the physician’s professional service separate from institutional technical component (rare for surgical procedure billing).
`50`	Bilateral procedure	When a biopsy is performed on extraocular muscles in both eyes during the same operative session.
`51`	Multiple procedures	When `67346` is reported with other unrelated CPT procedures during the same session and payer requires a multiple procedure modifier.
`52`	Reduced services	When the biopsy is limited or incomplete compared with the full documented procedure (e.g., specimen not obtained as planned).
`53`	Discontinued procedure	When the procedure is started but halted due to extenuating circumstances or patient safety concerns before a specimen is obtained.
`54`	Surgical care only	When another clinician bills for pre- and post-operative care and the surgeon bills for the intraoperative surgical service only.
`55`	Postoperative management only	When billing is for postoperative management only after a different clinician performed the surgery.
`62`	Two surgeons	When two surgeons of different specialties work together as primary surgeons performing distinct portions of the biopsy.
`78`	Return to operating room for a related procedure during the global period	When an additional operative procedure related to the initial biopsy is required and performed in the global period.
`79`	(Not in provided list)	Data not applicable — omitted.
`LT`	Left side	When the biopsy is performed on the left extraocular muscle.
`RT`	Right side	When the biopsy is performed on the right extraocular muscle.
`QX`	Coverage requirements met — modifier for assistant-at-surgery	When a qualified assistant-at-surgery participates and payer requires `QX` reporting.
`QY`	Medical direction of two, three, or four assistants	When medical direction of multiple assistants is documented and payer requires `QY`.

Taxonomy Code	Specialty	Notes
`207Y00000X`	Ophthalmology	Ophthalmologists commonly perform extraocular muscle biopsies, including strabismus and orbital subspecialists.
`207K00000X`	Oculoplastic Surgery (Ophthalmology)	Oculoplastic surgeons manage orbital and extraocular muscle pathology and perform biopsies.
`207L00000X`	Pediatric Ophthalmology	Pediatric ophthalmologists may perform biopsies in children with suspected myopathies or inflammatory conditions.
`364S00000X`	Ophthalmic Plastic and Reconstructive Surgery	Subspecialized providers performing orbital and muscle biopsies.
`2080S0126X`	Neuro-ophthalmology	Neuro-ophthalmologists involved when neuromuscular or neurologic causes of ocular motility disturbance are suspected.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`H50.0`	Strabismus	Misalignment of the eyes frequently prompts evaluation and may include biopsy when muscle pathology is suspected.
`H49.2`	Oculomotor nerve palsy	Neuromuscular causes of motility disturbance may lead to muscle biopsy if myogenic disease is suspected.
`H05.2`	Orbital myositis	Inflammatory enlargement of extraocular muscles often requires biopsy to confirm infectious vs inflammatory etiologies.
`M60.9`	Myositis, unspecified	When systemic or localized myositis involves extraocular muscles, biopsy confirms diagnosis and guides therapy.
`C79.8`	Secondary malignant neoplasm of other specified sites	Metastatic disease to extraocular muscle is uncommon but biopsy is definitive for diagnosis.
`G70.0`	Myasthenia gravis	Although primarily a neuromuscular junction disorder diagnosed with other tests, biopsy may be considered when alternate muscle pathology is suspected.
`H05.89`	Other disorders of orbit	Miscellaneous orbital conditions causing muscle enlargement or mass that may require tissue diagnosis.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`67311`	Recession or resection procedure of extraocular muscle; one horizontal muscle	Performed when strabismus correction is required; may be done concurrently or separately from diagnostic biopsy.
`67314`	Recession or resection procedure of extraocular muscle; one vertical muscle	Vertical muscle surgery for alignment that may be part of combined procedures addressing the underlying motility disorder.
`76512`	Ophthalmic ultrasound, diagnostic; orbit, globe and/or ocular adnexa, diagnostic B-scan	Imaging performed preoperatively to evaluate extraocular muscle enlargement or masses prior to biopsy.
`70486`	CT orbit without contrast	Cross-sectional imaging used to localize muscle pathology or guide surgical planning before biopsy.
`88305`	Level IV surgical pathology, gross and microscopic examination	Common pathology billing code for surgical muscle biopsy specimens submitted by the laboratory for histologic evaluation.
`99024`	Postoperative follow-up visit global period, related to whether separate postoperative care is billed	Documentation of routine postoperative visit during global surgical period; relates to billing and global period management for `67346`.