Summary & Overview
CPT 61566: Temporal Lobe Resection of Hippocampus and Amygdala
CPT code 61566 represents a neurosurgical craniotomy with resection of medial temporal structures — specifically removal of affected portions of the hippocampus and amygdala. This procedure is a key surgical option for patients with drug‑resistant temporal lobe epilepsy and certain focal temporal lobe lesions. Nationally, accurate coding and documentation for this code affect hospital case mix, resource allocation, and coverage decisions for high‑complexity neurosurgical care.
Key payers in the analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of clinical context for the procedure, typical sites of service, and commonly applied billing modifiers and service considerations. The publication outlines benchmarks for utilization and policy considerations that influence authorization and coverage for complex neurosurgical resections, as well as documentation elements that support medical necessity determinations.
The report is intended for hospital billing teams, neurosurgeons, revenue cycle leaders, and policy analysts who need a succinct reference on coding, clinical indications, and payer coverage patterns for CPT code 61566. Data not available in the input is noted where applicable.
Billing Code Overview
CPT code 61566 describes a neurosurgical procedure in which the surgeon raises a portion of the skull (craniotomy) to access and remove the affected portions of the hippocampus and amygdala. This operation is typically performed to treat refractory temporal lobe epilepsy or other focal temporal lobe pathologies when resection of these medial temporal structures is indicated.
Service type: Neurosurgical resection (temporal lobectomy/medial temporal resection)
Typical site of service: Inpatient hospital operating room
Clinical & Coding Specifications
Clinical Context
A typical patient is an adult with medically refractory temporal lobe epilepsy or a localized mesial temporal lesion (for example, a tumor, mesial temporal sclerosis, or intractable seizures originating in the hippocampus/amygdala) who has failed adequate trials of anti-seizure medications. The patient undergoes preoperative evaluation including neurologic exam, prolonged video EEG monitoring, high-resolution brain MRI, neuropsychological testing, and consultation with neurosurgery and epilepsy neurology. Surgical planning often includes neuronavigation and may include intraoperative electrocorticography or depth electrode mapping. In the operating room under general anesthesia, a craniotomy is performed to raise a portion of skull bone, the temporal lobe is exposed, and a selective or standard anterior temporal lobectomy is performed with resection of the affected hippocampus and amygdala. The immediate postoperative workflow includes transfer to a postanesthesia care unit or neurosurgical intensive care unit for neurologic monitoring, pain control, seizure monitoring, and imaging as indicated (typically a postoperative CT scan to assess for hemorrhage). Subsequent care includes inpatient neurological observation, anticonvulsant management, wound care, and scheduled outpatient follow-up with neurosurgery and epilepsy neurology for seizure outcome assessment and rehabilitation as needed.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | No modifier | Standard, no special circumstances reported |