N157 – Craniotomy plus removal - infratentorial
OHIP Otolaryngology Code — NEUROLOGICAL SURGICAL PROCEDURES · Schedule of Benefits
This service covers the surgical procedure of a craniotomy with the subsequent removal of a spontaneous intracerebral hemorrhage from the infratentorial area. The fee includes the primary surgical component (suffix A), with provisions for separately billable assistant (suffix B) and anaesthesia (suffix C) services. Assistant and anaesthesia fees are calculated based on their respective base units plus time units as outlined in the Schedule of Benefits.
When to Use
- Use N157 specifically for the evacuation of a spontaneous intracerebral hemorrhage located in the infratentorial (cerebellar or brainstem) region via craniotomy.
- Select N157 over N104 or N120 when the primary surgical objective is the removal of a spontaneous bleed rather than a tumor resection or decompression for other pathologies.
Common Pitfalls
- Billing N157 for supratentorial hemorrhages, which requires a different surgical code; ensure the operative report clearly specifies the infratentorial location.
- Attempting to bill a second surgical assistant without prior authorization, as N157 is not on the list of procedures with automatic second assistant eligibility.
Billing Tips
- Ensure the operative report explicitly documents the 'spontaneous' nature of the hemorrhage to support the medical necessity required by the Schedule of Benefits.
- If the procedure is performed on an emergency basis, verify that the start time is accurately recorded to support the application of after-hours premiums (E409/E410) or the trauma premium (E420) if the ISS criteria are met.
Effective: April 1, 2026
X. Neurological Surgical Procedures
NEUROLOGICAL SURGICAL PROCEDURES
Surgical
Neurological Surgical Procedures, Surgical Assistants' Services, Anaesthesiologists' Services
The medical record must establish that an insured service was provided, the service for which the account is submitted is the service that was rendered, and the service was medically necessary.
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