ABSTRACT
Patients with cochlear implants (CIs) commonly undergo neurosurgical interventions for concurrent pathologies. The neurosurgeon must be aware of the limitations these devices place on treating these patients and all pertinent interactions CIs have with common neurosurgical instruments and procedures. A literature search was performed utilizing the terms "cochlear implant" and "neurosurgery" or "neurosurgical" and all associated iterations. We reviewed the abstracts of 146 generated reports and eight published papers discussing the interaction and limitations of CI use in different neurosurgical procedures. Five realms were identified in which a CI may potentially interfere with standard neurosurgical care: Magnetic resonance imaging (MRI), radiotherapy, deep brain stimulation (DBS), intraventricular shunt placement, and intraoperative neuromonitoring (IONM). First, MRI use with CIs is limited due to thermal injury risk, imaging disruption, and implant damage. Secondly, high-dose >50 Gy single-fraction linear accelerator-based radiosurgery has been demonstrated to result in a loss of radio frequency link range in CIs, interfering with their function. Next, during surgery for DBS, the need for MRI and microelectrode recording requires CI magnet removal by neurotology and the surgeon must communicate with a non-hearing patient. Tunneling of shunts must accommodate CI position retroauricularly, if ipsilateral, and programmable valves must be placed >2 cm from the CI to prevent interference. Intraoperative neuromonitoring may produce voltages that interfere with CIs, and while monopolar cautery may pose the same risk, no study has proven this to date. Generally, bipolar cautery is safe and favored >1 cm from CIs. MRI use is limited in CI patients, although MRI-safer devices are in production. DBS electrodes may be successfully placed after CI magnet removal. Programmable shunt valves may be placed >2 cm away from CIs and radiosurgery <50 Gy has not demonstrated harm to these devices. IONM and monopolar cautery have not been demonstrated to directly affect CIs; however, more research is needed.
ABSTRACT
BACKGROUND: Cerebral palsy with medically refractory spasticity and dystonia is a condition that often benefits from intrathecal baclofen pump therapy to treat these symptoms. In this case report, an intracranial baclofen catheter was placed in the prepontine space to improve withdrawal symptoms in a patient unable to undergo new lumbar catheter placement due to infection. CASE DESCRIPTION: A 22-year-old female with past medical history of cerebral palsy presented with baclofen pump failure and was unable to undergo placement of a new lumbar baclofen catheter due to an infection in her lower back precluding safe and efficacious catheter placement. It was decided the patient would benefit from intrathecal baclofen administered in the prepontine space as a means to avoid a lumbar catheter and thus bypass this prior infection site. An endoscopic third ventriculostomy (ETV) was performed with the endoscope and the distal end of the baclofen pump catheter was fed through this ETV into the prepontine space. Placement in the prepontine space was confirmed by a follow-up head computed tomography. There was a significant improvement in autonomic symptoms and spasticity. By postoperative day 5, the patient was surgically and medically cleared for discharge. CONCLUSION: In cases of severe baclofen withdrawal due to dysfunctional pumps, immediate reversal is preferred but may not be feasible due to factors such as infection. This case report has demonstrated that prepontine catheter placement can be effective for the administration of baclofen to reverse withdrawal symptoms in these types of patients.
