Introduction: Intraoperative neurophysilogical monitoring (IOM) has been widespread in spine surgery. Little data is available about efficacy in percutaneos screws and transforaminal lumbar interbody fusion (TLIF).

Methods: We reviewed a retrospective chart of patients undergoing transforaminal interbody fusion y the last two years for the same surgeon. 25 patients were operated on 28 levels (mainly L4-5 75%) with 106 percutaneous screws.

Results: All screws were placed using two X-Ray technique without violation of the inferior or medial borders in AP view at posterior wall of the vertebral body in lateral view. None of stimulation of the screws got response under 12mA. During the insertion of the interbody cage two patients developed long lasting irritation of the nerve root. All patients were free of neurological deficits or radicular pain, except these two patients with transient paresia of L5 4-/5 with complete recovery in 4 weeks.

Conclusions: IOM is a valuable technique for assessing the nervous system during general anesthesia. Control of spinal cord is mandatory in some surgeries but the utility in other fields of the spine the utility is not so clear. No clear data is available about the results using IOM for lumbar spine but several cases with neurological damage happen even in the best hands and with the last technology available (such navigation or intraoperative CT). The X-ray in two views for minimally invasive percutaneous screws has been consolidated but few papers were published. In one of them showed not improvement in the patient outcome, considering low risk procedure. TLIF avoid main problems of posterior cages but in patients with narrow discs or severe stenosis. Stretching of the nerve roots could led to nerve injury. In this cases IOM assist the surgeon to minimize the manipulation of the neural tissue and avoid permanent damage.

Patient Care: Review the use of IOM in TLIF not only for screws, but also for insertion of the cage

Learning Objectives: By the conclusion IOM is a valuable tool to avoid neurological damaged and could assist the neurosurgeon during insertion of percutaneous screws and TLIF cages

References: Intraoperative Neurophysiological Monitoring for Minimally Invasive 1- and 2-Level Transforaminal Lumbar Interbody Fusion: Does It Improve Patient Outcome? Juanita Garces, MD, J. Franklin Berry, MS, Edison P. Valle-Giler, Phd, and Wale A. R. Sulaiman, MD, PhD