CPT 61305 Posterior Fossa Inspection Reimbursement | OpenPayer

Summary & Overview

CPT 61305: Inspection of Posterior Fossa via Subtentorial Approach

CPT code 61305 represents a neurosurgical procedure to inspect the posterior fossa—brain structures at the back of the skull—via a subtentorial approach. This operative inspection is performed when imaging and other diagnostic tests cannot locate a lesion, define a tumor, or explain neurologic impairment. Nationally, the code captures a specialized, primarily hospital-based surgical service that has implications for surgical workflow, inpatient resource use, and specialty reimbursement.

Key payers addressed in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise clinical context for the procedure, common billing modifiers and coding considerations, and where available, typical settings and service lines associated with the code. The publication also summarizes benchmarking and policy-relevant points that influence coverage and billing practice for intracranial posterior fossa inspection.

This summary equips clinicians, coding professionals, and policy analysts with a clear description of the procedure, the primary payers relevant to national billing, and the types of operational and documentation considerations tied to CPT code 61305. Data not available in the input will be noted where appropriate in detailed sections.

AetnaBlue Cross Blue ShieldCigna HealthUnitedHealthcareMedicare61305CPTneurosurgeryintracranial-surgeryposterior-fossaoperating-roomsurgical-inspectionsubtentorial-approach

Billing Code Overview

CPT code 61305 describes a surgical inspection of the posterior fossa of the brain through an approach below the tentorium. The procedure is used to directly visualize structures at the back of the skull when noninvasive diagnostic testing cannot determine the cause, precise location of a lesion or tumor, or the extent of injury.

Service type: Surgical intracranial inspection of posterior fossa structures
Typical site of service: Inpatient or outpatient hospital operating room or neurosurgical suite

Clinical & Coding Specifications

Clinical Context

A 56-year-old patient presents with progressive occipital headaches, gait instability, and new cranial nerve deficits. Neuroimaging (MRI) identifies a posterior fossa mass near the cerebellum and brainstem but cannot definitively define tumor margins or the lesion's relationship to critical vascular structures. The clinical team schedules a posterior fossa exploration via suboccipital craniotomy to directly inspect the posterior fossa below the tentorium for lesion localization, assessment of extent, and intraoperative decision-making regarding biopsy or resection. Preoperative workflow includes neurologic examination, MRI with and without contrast, anesthetic evaluation, informed consent describing risks specific to posterior fossa surgery, and coordination with radiology for intraoperative imaging if needed. Intraoperative workflow involves general endotracheal anesthesia, neuromonitoring (brainstem auditory evoked potentials, cranial nerve monitoring), suboccipital exposure, dural opening, microscopic inspection of the cerebellum and brainstem surfaces, possible biopsy or partial resection, hemostasis, and layered closure. Postoperative care includes neurologic monitoring in a neurosurgical unit, pain control, imaging to document resection or biopsy site, and rehabilitation as indicated.

Coding Specifications

Modifier	Description	When to Use
`22`	Increased procedural services	Use when work, time, or technical difficulty substantially exceeds typical expectations for a posterior fossa exploration.

CPT 61537: Temporal Lobe Resection for Epilepsy

CPT-61516-SUPRATENTORIAL-CYST-EXCISION-CRANIOTOMY

CPT 61516: Supratentorial Cyst Excision with Craniotomy

CPT-61333-SCALP-INCISION-ACCESS-TO-EYE-LESION-REMOVAL

CPT 61333: Scalp Incision to Access Eye for Lesion or Tumor Removal

CPT-61570-CRANIECTOMY-CRANIOTOMY-FOREIGN-BODY-EXCISION

CPT 61570: Craniectomy/Craniotomy, Excision of Foreign Body

CPT-61522-POSTERIOR-FOSSA-BRAIN-ABSCESS-EXCISION

CPT 61522: Posterior Fossa Brain Abscess or Lesion Excision

CPT-61312-SUPRATENTORIAL-HEMATOMA-EVACUATION-CRANIOTOMY

CPT 61312: Supratentorial Intracranial Hematoma Evacuation

CPT-61575-TRANSORAL-SKULL-BASE-BRAIN-STEM-UPPER-SPINAL-CORD-APPROACH

CPT 61575: Transoral Skull Base, Brain Stem, Upper Spinal Cord Approach

CPT-61545-CRANIOTOMY-CRANIOPHARYNGIOMA-RESECTION-SELLAR-SUPRASELLAR

CPT 61545: Craniotomy for Craniopharyngioma Resection

CPT-61556-CRANIAL-VAULT-REMODELING-FRONTAL-PARIETAL-BONE-FLAP

CPT 61556: Cranial Vault Remodeling for Craniosynostosis

CPT-61548-PITUITARY-TUMOR-RESECTION-TRANSNASAL-TRANSORAL

CPT 61548: Resection of Pituitary Gland or Tumor via Nose or Mouth

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Taxonomy Code	Specialty	Notes
207L00000X	Neurological Surgery	Primary specialty that performs posterior fossa exploration and craniotomy procedures.
2084P0800X	Neurology	May be involved pre- and postoperatively for diagnostic evaluation and management, less commonly as operative provider.
208000000X	Diagnostic Radiology	Provides intraoperative imaging support (fluoroscopy, intraoperative CT/MRI) and preoperative imaging interpretation.
363LF0000X	Anesthesiology	Provides intraoperative anesthesia services with expertise in neurosurgical anesthetic management.
1821P0802X	Physical Medicine & Rehabilitation	Involved in postoperative rehabilitation planning for cerebellar or brainstem deficits.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`C71.7`	Malignant neoplasm of cerebellum	Posterior fossa exploration is performed to localize, biopsy, or assess cerebellar tumors.
`D33.4`	Benign neoplasm of cerebellum	Surgery may be needed to diagnose or manage benign posterior fossa tumors causing mass effect.
`I62.0`	Nontraumatic subdural hemorrhage of the posterior fossa	Exploration may be required to identify source of bleeding and evacuate hematoma if indicated.
`G93.5`	Compression of brain	Posterior fossa inspection is indicated when mass effect or compression of brainstem/cerebellum is suspected.
`Q03`	Congenital hydrocephalus	In pediatric cases, exploration may be part of evaluating posterior fossa abnormalities contributing to hydrocephalus.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`61305`	Exploration of posterior fossa via suboccipital approach; inspection with or without biopsy	Primary procedure code describing direct inspection of the posterior fossa below the tentorium for lesion localization or biopsy.
`61304`	Craniectomy or craniotomy for posterior fossa, exploratory, without lesion removal	May be used for broader posterior fossa exposures where exploration is documented without biopsy or resection.
`61312`	Removal of posterior fossa lesion; partial or gross total resection	Represents subsequent definitive resection when exploration identifies a resectable lesion; used when tissue removal is performed.
`61154`	Craniectomy or craniotomy, suboccipital, for decompression	Performed when posterior fossa exploration is done with the intent of decompression (e.g., for Chiari malformation or mass effect) in addition to inspection.
`61616`	Stereotactic biopsy, brain; needle or open, with CT or stereotactic guidance	Used when a stereotactic approach is chosen for sampling rather than open suboccipital exploration; may be an alternative or adjunct depending on lesion location.

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