Summary & Overview

CPT 31291: Endoscopic Nasal Repair of CSF Leak in Sphenoid Sinus

CPT code 31291 represents endoscopic repair of a cerebrospinal fluid (CSF) leak in the sphenoid sinus, performed via a nasal endoscope and often involving tissue grafting. The procedure is a key component of skull base and sinonasal surgery when CSF fistulae threaten intracranial complications, and it is relevant for hospitals, ambulatory surgery centers, and specialist surgeons nationwide. Covered payers in this overview include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare.

Readers will find a concise clinical and billing orientation to the procedure, a review of payer coverage patterns and common modifiers, and context on sites of service and typical clinical indications. The publication summarizes benchmarks and policy-relevant considerations that affect coding and reimbursement for endoscopic skull base repairs, highlights clinical workflow implications for otolaryngology and neurosurgery teams, and notes where input data is not available. This national-level summary aims to clarify what CPT code 31291 represents, why it matters for patient safety and hospital operations, and what operational and billing areas clinicians and administrators should review when this procedure is performed.

AetnaBlue Cross Blue ShieldCigna HealthUnitedHealthcareMedicareCPT 31291endoscopic skull base surgeryCSF leak repairsphenoid sinusnasal endoscopyENT surgeryneurosurgeryambulatory surgery centerprocedure coding

Billing Code Overview

CPT code 31291 describes an endoscopic nasal procedure to repair a cerebrospinal fluid (CSF) leak in the sphenoid sinus, often using a tissue graft such as muscle. This is a surgical repair of a CSF leak via nasal endoscopy.

Service type: Endoscopic sinus/skull base surgical procedure

Typical site of service: Hospital outpatient department or ambulatory surgery center, performed by otolaryngology or neurosurgery teams using nasal endoscopic techniques.

Data not available in the input.

Clinical & Coding Specifications

Clinical Context

A 48-year-old patient presents with clear unilateral rhinorrhea that increases with Valsalva and positional changes, recurrent meningitis, and imaging (CT and MRI) demonstrating a defect of the lateral wall of the sphenoid sinus with associated cerebrospinal fluid (CSF) leak. The otolaryngology/neurosurgery team schedules an endoscopic transnasal repair. Under general anesthesia in an operating room setting, the surgeon inserts a nasal endoscope (31291) to localize the sphenoid sinus defect, confirms active CSF egress, and harvests a graft (for example, autologous fascia or muscle) or uses a free mucosal/vascularized flap to seal the leak. Intraoperative steps include endoscopic visualization, defect debridement, graft placement with multilayer closure when indicated, and intraoperative Valsalva to test closure integrity. Postoperative workflow includes short observation in a post-anesthesia care unit, possible inpatient monitoring if meningitis risk or neurosurgical involvement exists, head-of-bed elevation, avoidance of nose-blowing, and outpatient follow-up with endoscopic inspection. Typical site of service is the hospital operating room or ambulatory surgery center. Service type is endoscopic skull base repair/CSF leak repair via transnasal endoscopic approach.

Coding Specifications

Modifier	Description	When to Use
`22`	Increased procedural services	When work, time, or complexity substantially exceeds typical for `31291`.
`23`	Unusual anesthesia	When general anesthesia is medically contraindicated and local/regional anesthesia is used unusually.
`26`	Professional component	When reporting only the professional interpretation/operative service separate from technical facility charges (rare for `31291`).
`50`	Bilateral procedure	When bilateral endoscopic repairs are performed in the same operative session.
`51`	Multiple procedures	When `31291` is performed with other distinct procedures during the same operative episode.
`52`	Reduced services	When the service is partially reduced or not completed as planned.
`53`	Discontinued procedure	When the procedure is terminated due to extenuating circumstances after initiation.
`59`	Distinct procedural service	When a separate unrelated procedure is performed in a different anatomical site or at a distinct session on the same day.
`62`	Two surgeons	When two surgeons work together as primary surgeons for a complex skull base repair.
`78`	Return to the operating room (unplanned)	For an unplanned return to the OR for a related procedure during the global period.

Taxonomy Code	Specialty	Notes
207Y00000X	Otolaryngology (ENT)	Primary specialty performing endoscopic skull base and sinus surgery.
2084P0800X	Neurosurgery	Often co-manages skull base CSF leak repairs, particularly with intracranial extension.
207K00000X	Facial Plastic Surgery	May participate when sinonasal reconstruction or external approaches are needed.
208000000X	Surgery (general)	Occasionally involved in multidisciplinary skull base cases in some centers.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`G96.0`	Cerebrospinal fluid leak, intracranial	Direct indication for endoscopic CSF leak repair in the sphenoid sinus.
`J34.89`	Other specified disorders of nose and nasal sinuses	May be used for unspecified sphenoid sinus pathology associated with leak when more specific code not available.
`G00.9`	Bacterial meningitis, unspecified	Complication of CSF leak prompting repair to prevent recurrent meningitis.
`S05.89XA`	Other injury of orbit, initial encounter	Traumatic defects causing CSF leak may use related trauma codes in the acute setting.
`D33.3`	Benign neoplasm of pituitary gland	Pituitary lesions adjacent to the sphenoid that can lead to CSF leak or require concurrent management.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`31295`	Nasal/sinus endoscopy, surgical; with repair of CSF leak of anterior skull base	Alternative or adjacent code used for CSF leak repairs involving the frontal or ethmoid skull base; may be reported if the leak is not confined to the sphenoid.
`61582`	Transnasal or transsphenoidal excision of pituitary tumor, endoscopic or microscopic, with or without intraoperative imaging	Performed when a concomitant sellar lesion necessitates tumor resection during the same endoscopic approach.
`20936`	Muscle, myocutaneous, or fasciocutaneous flap; trunk	When a regional or free flap harvest is required for skull base reconstruction adjunctive to the endoscopic repair.
`31237`	Nasal/sinus endoscopy, diagnostic	Used preoperatively or intraoperatively for diagnostic endoscopic evaluation of the nasal cavity and sinuses prior to definitive `31291` repair.
`76937`	Ultrasound guidance for vascular access requiring ultrasound guidance and imaging documentation	May be used intraoperatively for vascular access or monitoring adjuncts during complex cases.