Abstract

GA2-58

Intramedullary Spinal Cord Tumor Resection: a tailored anesthetic

Than K, Bell M, Costandi A
Children's Hospital Los Angeles, Pasadena, CA, USA

Presented is a 15 year old male in need of C2-T3 intramedullary spinal cord tumor resection. After IV midazolam, general anesthesia was induced with lidocaine, fentanyl, ketamine and propofol. Deep intubation was performed without muscle relaxant to ensure return of spontaneous respiration as quickly as possible. An arterial line was placed and adequate IV access obtained. Pacer pads were applied and he was positioned prone in the mayfield frame. Maintenance was accomplished with total intravenous anesthesia (TIVA) using a combination of propofol, remifentanil, ketamine, and dexmedetomidine infusions. BIS monitoring was utilized to maintain adequate depth of anesthesia. To decrease blood loss we used a tranexamic acid infusion for antifibinolytic therapy and dopamine infusion was titrated to maintain spinal cord perfusion. Neuro electrophysiologic monitoring included motor evoked potentials (MEPs), somatosensory evoked potentials (SSEPs), and D-waves. All signals remained stable throughout the case (Image 1). At the conclusion of the case, the patient was returned to the supine position and he was successfully extubated without new neurologic deficit.

Two aspects of this tumor location make the anesthetic requirements unique. First, proximity of the tumor to the phrenic nerve fibers (C3-C5). Second, tumor proximity to the cardiac accelerator fibers (T1-T4). The surgeon requested we maintain spontaneous respiration during tumor resection in order to detect phrenic nerve trespass. Pacer pads were applied to the patient preemptively in the event of cardiac accelerator trespass and refractory bradycardia. Optimal conditions for intraoperative neurologic monitoring (IOM) were also required.

The ideal anesthetic would achieve adequate depth of anesthesia without muscle relaxant, provide stable hemodynamics, and allow the patient to be extubated at the conclusion of the procedure. We achieved this goal by using a multi-modal anesthetic approach combining several anesthetic agents at low doses. Halogenated agents were avoided due to their effects on IOM. Remifentanil was used to provide stable analgesia that could be titrated to respiratory effort and quickly weaned. Propofol maintained unconsciousness and amnesia combined with dexemedetomide and ketamine to allow to lower doses of each agent to be used. Despite the challenges faced due to location of the tumor, patient positioning, and maintenance of anesthesia for IOM, we achieved safe conditions for adequate resection and a positive outcome.

References
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