CPT® Code 61567

The procedure described by CPT® Code 61567 involves a craniotomy with the elevation of a bone flap specifically for the purpose of performing multiple subpial transections (MST) accompanied by electrocorticography (ECoG) during the surgical intervention. This complex neurosurgical procedure is typically indicated for patients suffering from mesial temporal lobe epilepsy that has not responded to conventional medical therapies. The craniotomy allows for direct access to the brain, where various approaches can be utilized, including the subtemporal, transcortical, or transsylvian methods, depending on the specific anatomical considerations and the surgeon's preference. During the procedure, the patient's head is secured using a three-pin fixation device to ensure stability. An incision is made in the temporal area to expose the temporalis fascia, which is then carefully opened and separated from the underlying periosteum. The skin and muscle flap are retracted laterally to provide adequate access to the skull. A bone flap is elevated using burr holes and a craniotome, allowing the dura mater to be opened and flapped anteriorly, thereby exposing the brain cortex. The use of electrocorticography during the surgery is crucial, as it enables the surgeon to map the brain's electrical activity in real-time, helping to identify the boundaries between the epileptogenic zones and the functional areas of the cortex. This mapping is essential for the safe and effective execution of the subpial transections, which involve making small, shallow incisions in the nerve fibers located just beneath the pia mater. The procedure concludes with meticulous hemostasis, closure of the dura, and reattachment of the bone flap, followed by the reapproximation of the temporalis muscle and layered closure of the scalp. This detailed approach aims to alleviate the patient's seizure activity while preserving as much functional brain tissue as possible.