1. Procedure and CPT® Code Selection:

The patient requires a surgical nasal sinus endoscopy to repair a cerebrospinal fluid (CSF) leak caused by a skull fracture that resulted in CSF draining into the nasal passage.

Code 31291 is the correct CPT® code for an endoscopic repair of a cerebrospinal fluid leak in the sphenoid sinus. This procedure code is appropriate because it specifically addresses surgical endoscopy for CSF leak repair in the sinus region.

Other codes provided, such as 31287 (nasal/sinus endoscopy with balloon dilation) and 31235 (nasal endoscopy with biopsy), do not match the description for surgical repair of a CSF leak and are therefore inappropriate for this case.

2. Diagnosis and ICD-10-CM Code Selection:

ICD-10-CM Code S02.19XA is used to describe a fracture of the anterior cranial base, which fits the described injury of the skull with cerebrospinal fluid leakage.

External cause code V47.5XXA is used for motor vehicle accidents involving a car hitting a stationary object.

Y92.411 is the appropriate code to describe the location of the accident as a highway.

3. Exclusion of Additional Procedure Codes:

There is no need for a second endoscopy code or a modifier, as 31291 fully describes the endoscopic repair procedure for the CSF leak.

4. AAPC and CPT® Coding Guidelines:

Per AAPC guidelines, procedure codes for sinus endoscopy are chosen based on the specific type of intervention (e.g., CSF leak repair). The guidelines for ICD-10-CM stress including external cause codes and location codes for trauma cases related to motor vehicle accidents.

Thus, the correct answer based on CPT® and ICD-10-CM coding standards is B. 31291, S02.19XA, V47.5XXA, Y92.411.