The Safety Of Keyhole Surgery For The Resection Of Spinal Cord Tumors

Object Using Intraoperative Neurophysiological Monitoring(IONM)to show that a minimally invasive percutaneous keyhole surgery is safe for patients with spinal cord tumors.Methords This study is a retrospective review of 40 patients who underwent keyhole surgery with multi-modality Intraoperative Neurophysiological Monitoring consisting of somatosensory evoked potentials(SEP),transcranial electric motor evoked potentials(MEP),and free-run electromyography(EMG)between January 2013 to December 2013.A diameter of 2.5 cm working channel was percutaneously inserted on the surgery.The hemilamina or partial articular where the tumor located was removed and the tumor in the spinal canal was removed under the microscope after opening the dura mater near the tumor surface.Using IONM to monitoring the spinal cord function.Changes in SEP or MEP were considered to be pathological if there was a decrease in amplitude more than 50%,as well as prolonged EMG discharges.Evaluate postoperative neurological function through the combined VAS score and ASIA score.Difference in outcome was tested for significance using paired t-tests.Results The average operation time was(176.5±25.3)min,the average blood loss was(51.13±2.86)ml,No patient had cerebrospinal fluid leakage.32 of 40 patients didn’t have significant change in signal.None of the patients had any perioperative neurologic deficit up to the date of follow up.VAS and ASIA were significantly improved after the surgery.In 40 consecutive patients we had 8 IONM alerts: three patients had SEP alone alarm.Blood pressure decreased for one of the patients decreased to 60/30 mm Hg during surgery.After using dopamine to raise blood pressure,SEP amplitude climb up to 70% of baseline level in 15 minutes then came back to baseline level after 1 hour.In addition,inhalation anesthesia was added to the other two cases at the beginning of the operation then changed to total intravenous anesthesia during the surgery,SEP amplitude returned to the baseline after 30 minutes.MEP alarm alerted when using muscle relaxant for one of the patients.It returned to baseline 45 minutes after stopping the muscle relaxant.One patient had both SEP and MEP alerted at the same time.After checking anesthesia,body temperature,blood pressure and other interference factors,the alarm signal could not be lifted.There was no change in VAS score before and after the operation,and the strength of the quadriceps changed from 4+ to 4-,the muscle strength of both lower limbs returned to the preoperative level after half-month follow-up.3 cases of EMG alone alerts,after suspending the spinal cord and nerve root pulling,the explosive myoelectric activity disappeared.All 40 patients removed the tumors completely.During the 1year to 3 years follow-up period no tumor recurred.Sensor and motor system recovered.Conclusion IONM is helpful to discover new nerve deficit in time and effective measures can be taken to prevent postoperative neurological damage.Keyhole surgery has less nerve harassment and fewer complications,so it’s safe and feasible for the Resection of spinal cord tumors.