Update on the neuromonitoring procedures applied during surgeries of the spine – observational study

Abstract

IntroductionMotor evoked potentials (MEPs) are currently considered as a more useful method for neurophysi-ological intraoperative monitoring than somatosensory evoked potentials in cases of surgery applied to patients with adolescent idiopathic scoliosis. The non-invasive approach is preferred to modify MEP recordings, criticizing, in many cases, the fundamentalism for neurophysiological monitoring based only on needle recordings. The aim of the review is to provide our own experience and prac-tical guidelines with reference to neuromonitoring innovations.Material and MethodsRecordings of MEPs with surface electrodes instead of needle electrodes including nerve instead of muscle combinations during neurophysiological monitoring associated with surgical interventions to the spine have become more relevant for pediatric purposes, avoiding the anesthesiology-related influences. Observations on 280 patients with Lenke A–C types of spine curvature are presented before and after the surgical correction.ResultsThe MEPs recorded from nerves do not undergo fluctuations at different stages of scoliosis correc-tions and the anesthesia effect more than MEPs recorded from muscles. The use of non-invasive surface electrodes during neuromonitoring for MEP recordings shortens the total time of the surgical procedure without diminishing the precision of the neural transmission evaluation. The quality of MEP recordings during intraoperative neuromonitoring from muscles can be significantly influ-enced by the depth of anesthesia or administration of muscle relaxants but not those recorded from nerves.ConclusionsThe proposed definition of “real-time” neuromonitoring comprises the immediate warning from a neurophysiologist about the changes in a patient’s neurological status during scoliosis surgery (es-pecially during pedicle screws’ implantation, corrective rods’ implantation, correction, distraction and derotation of the spine curvature) exactly during the successive steps of corrective procedures. This is possible due to the simultaneous observation of MEP recordings and a camera image of the surgical field. This procedure clearly increases safety and limits financial claims resulting from possible complications.

Comparison of Motor Evoked Potentials Neuromonitoring Following Pre- and Postoperative Transcranial Magnetic Stimulation and Intraoperative Electrical Stimulation in Patients Undergoing Surgical Correction of Idiopathic Scoliosis

“…Similarly to Gadella et al [30] and Duffler et al [31], we observed in T0 twice as many incidents of impedances of surface electrodes than needle electrodes, which did not significantly influence the signal-to-noise ratio parameter, and demonstrated the high utility of both methods in neuromonitoring procedures. Our previous pilot results on improving the neuromonitoring methodology [32] are fully compatible with their observations. Moreover, taking into account the fact that IS surgeries are pediatric and the consequences of neuromonitoring procedures using TES when MEPs are recorded with needle electrodes can be ecchymosis and bruises associated with the stimulation-related muscle movements, local nerve damage or infections in rare cases [50], and, frequently, postoperative skin reddening [51], recording from the muscle's surface is more beneficial.…”

“…In this paper, we describe the results of the studies with the methodology of the MEP recordings using the surface electrodes from the tibialis anterior muscle bilaterally, which is more and more widely used not only in pre-and postoperative diagnostic purposes but also has been proven to be precise enough for intraoperative monitoring in comparison to the standard needle electrodes [30,31]. Our previous pilot results on improving the neuromonitoring methodology [32] are fully compatible with such observations. It has not yet been documented whether the results of MEP recordings induced by the transcranial single magnetic stimulus can be compared with MEPs induced with the trains of electrical stimuli applied intraoperatively for diagnostic evaluation of the spinal neural transmission.…”

“…The needle ground electrode was applied in the area of the iliac crest. We used our experience in the utilization of the surface electrodes for MEP recording from TA muscles according to the previous descriptions [32]. Their impedance measured at the beginning of the neuromonitoring sessions was 10-20 kΩ.…”

Clinical Neurophysiological Methods Verify Improvement in the Motor Neural Transmission in Patients with Surgically Treated Idiopathic Scoliosis in Long-Term Follow-up

“…Neurophysiological assessment has the most important intraoperative significance when neuromonitoring the conduction of neural impulses within the spinal cord pathways [25]; however, preoperatively, in patients with IS, it supports the clinical assessments when making decisions about surgical treatment [26]. Few studies in the field of clinical neurophysiology presenting postoperative recordings, especially of motor-evoked potentials, proved an immediate functional improvement in the efferent conduction of spinal pathways in IS patients [7].…”

“Real-Time Neuromonitoring” Increases the Safety and Non-Invasiveness and Shortens the Duration of Idiopathic Scoliosis Surgery

“…The standards of neuromonitoring are constant and consist of checking every step of the surgical procedure and reacting to improper incidents [ 20 ]. Although a consensus-based checklist to guide the surgeon’s reactions to IONM changes and best-practice guidelines for their recording have been formulated [ 21 ], and their agreement has been confirmed and validated [ 22 ], new concepts have since been developed [ 23 , 24 , 25 ]. It is obvious that the surgical team of spine surgeons, anesthesiologists, and neurophysiologists cooperate more efficiently if their experience, technical skills, and equipment are advanced [ 26 ].…”