Update on neuromonitoring procedures applied during surgery of the spine - observational study.

Introduction: Motor evoked potentials (MEPs) are currently considered as a more useful method for neurophysiological 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 practical guidelines with reference to neuromonitoring innovations. Material and methods: Recordings 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. Results: The MEPs recorded from nerves do not undergo fluctuations at different stages of scoliosis corrections 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 influenced by the depth of anesthesia or administration of muscle relaxants but not those recorded from nerves. Conclusions: The 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 (especially 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.

The method for measurement of the three-dimensional scoliosis angle from standard radiographs.

BACKGROUND: Three-dimensional idiopathic scoliosis cannot be accurately assessed with the aid of a single plane parameter - the Cobb angle. We propose a novel method for evaluating the three-dimensional (3D) pattern of scoliosis based on two X-rays (PA and lateral). The proposed method consists of the measurements of the angles between the upper endplate of the upper-end vertebra and the lower endplate of the lower-end vertebra (3D scoliosis angle). METHODS: The 3D-angles of thirty scoliosis curves were measured with either computed tomography (CT) or digitally reconstructed radiographs (DRRs): PA and lateral. CT was used as a reference. In the case of CT, the 3D angle was calculated based on the coordinates of three points situated on the upper endplate and those of three points situated on the lower endplate of the scoliosis curve. In the case of the DRR, the 3D angle was calculated using the four-angle method: the angles formed by the endplates of the curve with the transverse plane. The results were tested with the Student's t-test, and the agreement of measurements was tested with the intraclass correlation coefficient. RESULTS: There was no significant difference between the 3D-angle measurements obtained with DRRs versus CT, p > 0.05. There was, however, a significant difference between the 3D-scoliosis angle and the Cobb angle measurements performed based on the X-rays. The reproducibility and reliability of 3D angle measurements were high. CONCLUSIONS: Based on two standard radiographs, PA and lateral, it is possible to calculate the 3D scoliosis angle. The proposed method facilitates 3D-scoliosis assessment without the use of sophisticated devices. Considering the 3D nature of AIS, the 3D parameters of the spine may help to apply a more effective treatment and estimate a more precise prognosis for patient with scoliosis.

Cervical cages placed bilaterally in the facet joints from a posterior approach significantly increase foraminal area.

PURPOSE: Foraminal stenosis is a common cause of cervical radiculopathy. Posterior cervical cages can indirectly increase foraminal area and decompress the nerve root. The aim of this study was to assess the influence of bilateral posterior cervical cages on the surface area and shape of the neural foramen. METHODS: Radiographic analysis was performed on 43 subjects enrolled in a prospective, multi-center study. CT scans were obtained at baseline and 6- and 12-months after cervical fusion using bilateral posterior cervical cages. The following measurements were performed on CT scan: foraminal area (A), theoretical area (TA), height (H), superior diagonal (DSI), inferior diagonal (DIS), and inferior diagonal without implant (DISI). Comparisons were performed using R-ANOVA with a significance of α < 0.05. RESULTS: Foraminal area, height, TA and DISI were significantly greater following placement of the implant. The mean (SD) A increased from 4.01 (1.09) mm(2) before surgery to 4.24 (1.00) mm(2) at 6 months, and 4.18 (1.05) mm(2) at 12 months after surgery (p < 0.0001). Foraminal height (H) increased from mean (SD) 9.20 (1.08) mm at baseline to 9.65 (1.06) mm and 9.55 (1.14) mm at 6- and 12-months post-operatively, respectively (p < 0.0001). The mean DIS did not change significantly. There was a significant decrease in DSI: 6.18 (1.59) mm pre-operatively, 5.95 (1.47) mm and 5.73 (1.46) mm at 6- and 12-months (p < 0.0001). CONCLUSIONS: Implantation of bilateral posterior cervical cages can increase foraminal area and may indirectly decompress the nerve roots. Correlation between increase in foraminal area and clinical outcomes needs further investigation.

Influence of cervical spine position on the radiographic parameters of the thoracic inlet alignment.

PURPOSE: Cervical sagittal balance is a complex phenomenon, influenced by many factors, which cannot be described by cervical lordosis alone. Attention has been focused on the relationship between T1 slope, thoracic inlet angle, and cervical sagittal balance. However, the effect of cervical position on these parameters has not been evaluated yet. The aim of this study was to assess the influence of cervical flexion and extension on radiographic thoracic inlet parameters. METHODS: 60 patients with one level radiculopathy symptoms underwent radiological examination. Mean age was 53 (40-72) years; there were 24 males and 34 females. Lateral standing X-rays of cervical spine were taken on the same day in neutral position, full flexion and full extension. Patients with previous cervical operations or congenital malformations were excluded. Thoracic inlet angle (TIA), neck tilt (NT) and thoracic (T1) slope were measured. Agreement between measurements was assessed and quantified by intra-class correlation coefficient (ICC) and median error for a single measurement (SEM). The ICC value greater than 0.75 reflected sufficient agreement. RESULTS: The mean values of the parameters were: (1) for the neutral position: TIA 71.7° ± 9.5°; T1 slope 26.7° ± 6.3°; and NT 44.9° ± 7.2°, (2) In extension: TIA 71.8° ± 9.4°; T1 slope 24.9° ± 7.6°; and NT 46.9° ± 7.2° and (3) In flexion 78.3° ± 10.3°; T1 slope 33.6° ± 7.8°; and NT 44.7° ± 7.4°. An excellent agreement was revealed for all NT measurements (ICC 0.76) and for TIA measured in flexion and neutral position (ICC 0.79). There was insufficient overall and in-pairs agreement for T1 slope measurements. CONCLUSIONS: Neck tilt measurements were not influenced by position of the cervical spine. T1 slope was significantly influenced by flexion and extension of the neck. This puts the concept that TIA is a morphologic parameter into question. This information should be taken into consideration when analyzing lateral radiographs of the cervical spine for clinical decision-making.

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

Introduction: A practical solution to the incidental unreliability of intraoperative neuromonitoring (IONM) may be the simultaneous neurophysiological recording and control of the surgical field through a camera (the concept of "Real-time" IONM). During "Real-time" IONM, the surgeon is immediately warned about the possibility of damage to the neural structures during, but not after, standard idiopathic scoliosis (IS) corrective surgery procedures (the concept of "Surgeon-neurophysiologist" interactive, verbal IONM). This study aimed to compare the advantages, utilities, reliabilities, and time consumption of the two IONM scenarios. Methods: Studies were performed in two similar groups of patients undergoing surgery primarily due to Lenke 2 idiopathic scoliosis (N = 120), when both IONM approaches were applied. Neurophysiological evaluations of the spinal transmission were performed pre- (T0), intra- (before (T1) and after (T2) surgery), and postoperatively (T3), as well as once in healthy volunteers (control, N = 60). Non-invasive and innovative recordings of the motor evoked potentials (MEPs) bilaterally from the peroneal (PER) nerve and tibialis anterior (TA) muscle were performed with surface electrodes as a result of transcranial magnetic stimulation (TMS) or electrical stimulation (TES) at T0-T3. Results: In both groups, the MEP amplitudes and latencies recorded from the PER nerve were approximately 67% lower and 3.1 ms shorter than those recorded from the TA muscle. The MEP recording parameters differed similarly at T0-T3 compared to the control group. In all patients, the MEP parameters induced by TMS (T0) and TES (T1) did not differ. The MEP amplitude parameters recorded from the TA and PER at T1 and T2 indicated a bilateral improvement in the neural spinal conduction due to the surgical intervention. The TMS-induced MEP amplitude at T3 further increased bilaterally. In both IONM groups, an average 51.8 BIS level of anesthesia did not affect the variability in the MEP amplitude, especially in the PER recordings when the applied TES strength was 98.2 mA. The number of fluctuations in the MEP parameters was closely related to the number of warnings from the neurophysiologist during the transpedicular screw implantation, corrective rod implantation, and distraction, derotation, and compression procedures, and it was higher in the "Surgeon-neurophysiologist" IONM group. The average duration of surgery was shorter by approximately one hour in the "Real-time" IONM group. The number of two-way communications between the surgeon and the neurophysiologist and vice versa in the "Real-time" IONM group decreased by approximately half. Conclusions: This study proves the superiority of using "Real-time" IONM over the standard "Surgeon-neurophysiologist" IONM procedure in increasing the safety and non-invasiveness, shortening the time, and lowering the costs of the surgical treatment of IS patients. The modifications of the MEP nerve-conduction-recording technology with surface electrodes from nerves enable precise and reliable information on the pediatric patient's neurological condition at every stage of the applied surgical procedures, even under conditions of slight fluctuations in anesthesia.

Radiological Outcomes of Magnetically Controlled Growing Rods for the Treatment of Children with Various Etiologies of Early-Onset Scoliosis-A Multicenter Study.

Background: The management of spinal deformities diagnosed before the age of 10 is critical due to the child's development, skeletal system, and growth mechanism. Magnetically controlled growing rods (MCGRs) are a surgical treatment option for the growing spine. The aim of this study was to analyze the radiological findings of patients treated with MCGRs for early-onset scoliosis (EOS) of various etiologies. We hypothesized that the MCGRs could provide acceptable long-term radiographic results, such as an increase in the T1-T12 and T1-S1 height and significant overall deformity correction. Methods: We retrospectively reviewed 161 EOS patients with a combined total of 302 MCGRs inserted at five institutions between 2016 and 2022 with a mean follow-up of at least two years. The Cobb angle of the major curve (MC), thoracic kyphosis (TK), lumbar lordosis (LL), and T1-T12 and T1-S1 height measurements were assessed before, after, and during the follow-up. Results: Among the 90 female and 71 male patients, there were 51 neurological, 42 syndromic, 58 idiopathic, and ten congenital scoliosis etiologies. Of the patients, 73 were aged under six years old. The mean follow-up time was 32.8 months. The mean age at placement of the MCGRs was 7 years and that at the last follow-up after fusion surgery was 14.5 years. The mean MC before the initial surgery was 86.2°; following rod implantation, it was 46.9°, and at the last follow-up visit, it was 45.8°. The mean correction rate among the etiology subgroups was from 43% to 50% at follow-up. The mean TK was noted as 47.2° before MCGR implantation, 47.1° after MCGR placement, and 44.5° at the last follow-up visit. The mean T1-T12 height increased by 5.95 mm per year, with a mean T1-S1 height of 10.1 mm per year. Conclusions: MCGR treatment allowed for an average correction of the curvature by 50% during the period of lengthening, while controlling any deformity and growth of the spine, with a significant increase in the T1-T12 and T1-S1 values during the observation period. MCGR treatment in EOS carries a risk of complications. While congenital and syndromic EOS often have short and less flexible curves in those groups of patients, single rods can be as effective and safe. Definitive fusion results in the mean final coronal correction between the start of MCGR treatment and after undergoing PSF of approximately 70%. The mean T1-T12 spinal height increased by 75 mm, while the T1-S1 spinal height gained a mean of 97 mm.

Reply to Tabeling et al. Comment on "Grabala et al. Radiological Outcomes of Magnetically Controlled Growing Rods for the Treatment of Children with Various Etiologies of Early-Onset Scoliosis-A Multicenter Study. J. Clin. Med. 2024, 13, 1529".

We are immensely gratified by the considerable interest our study has garnered [...].

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.

The relationships between the results of pre- and intraoperative motor evoked potential recordings during neuromonitoring and whether idiopathic scoliosis (IS) surgical correction improves the spinal efferent transmission have not been specified in detail. This study aims to compare the results of surface-recorded electromyography (EMG), electroneurography (ENG, M, and F-waves), and especially motor evoked potential (MEP) recordings from tibialis anterior muscle (TA) bilaterally in 353 girls with right idiopathic scoliosis (types 1-3 according to Lenke classification). It has not yet been documented whether the results of MEP recordings induced by transcranial single magnetic stimulus (TMS, pre- and postoperatively) and trains of electrical stimuli (TES; intraoperatively in T0-before surgery, T1-after pedicle screws implantation, and T2-after scoliosis curvature distraction and derotation following two-rod implantation) can be compared for diagnostic verification of the improvement of spinal cord neural transmission. We attempted to determine whether the constant level of optimal anesthesia during certain surgical steps of scoliosis treatment affects the parameters of MEPs recorded during neuromonitoring procedures. No neurological deficits have been observed postoperatively. The values of amplitudes but not latencies in MEP recordings evoked with TMS in IS patients compared before and after surgery indicated a slight improvement in efferent neural transmission. The results of all neurophysiological studies in IS patients were significantly asymmetrical and recorded worse on the concave side, suggesting greater neurological motor deficits at p = 0.04. The surgeries brought significant improvement (p = 0.04) in the parameters of amplitudes of sEMG recordings; however, the consequences of abnormalities in the activity of TA motor units were still reflected. ENG study results showed the symptoms of the axonal-type injury in peroneal motor fibers improving only on the concave side at p = 0.04, in parallel with F-wave parameters, which suggests that derotation and distraction might result in restoring the proper relations of the lumbar ventral roots in the spinal central canal, resembling their decompression. There were no significant differences detected in the amplitudes or latencies of MEPs induced with TMS or TES when comparing the parameters recorded preoperatively and intraoperatively in T0. The amplitudes of TES-evoked MEPs increased gradually at p = 0.04 in the subsequent periods (T1 and T2) of observation. A reduction in MEP latency at p = 0.05 was observed only at the end of the IS surgery. Studies on the possible connections between the level of anesthesia fluctuations and the required TMS stimulus strength, as well as the MEP amplitude changes measured in T0-T2, revealed a lack of relationships. These might not be the factors influencing the efferent transmission in spinal pathways beside the surgical procedures. Pre- (TMS-evoked) and intraoperative (TES-evoked) recordings are reliable for evaluating the patient's neurological status before and during surgical scoliosis correction procedures. An increase in MEP amplitude parameters recorded on both sides after scoliosis surgery proves the immediate improvement of the total efferent spinal cord transmission. Considering comparative pre- and postoperative sEMG and ENG recordings, it can be concluded that surgeries might directly result in additional lumbar ventral root decompression. We can conclude that MEP parameter changes are determined by the surgery procedures during neuromonitoring, not the anesthesia conditions if they are kept stable, which influences a decrease in the number of false-positive neuromonitoring warnings.

Automatic Spine Tissue Segmentation from MRI Data Based on Cascade of Boosted Classifiers and Active Appearance Model.

The study introduces a novel method for automatic segmentation of vertebral column tissue from MRI images. The paper describes a method that combines multiple stages of Machine Learning techniques to recognize and separate different tissues of the human spine. For the needs of this paper, 50 MRI examinations presenting lumbosacral spine of patients with low back pain were selected. After the initial filtration, automatic vertebrae recognition using Cascade Classifier takes place. Afterwards the main segmentation process using the patch based Active Appearance Model is performed. Obtained results are interpolated using centripetal Catmull-Rom splines. The method was tested on previously unseen vertebrae images segmented manually by 5 physicians. A test validating algorithm convergence per iteration was performed and the Intraclass Correlation Coefficient was calculated. Additionally, the 10-fold cross-validation analysis has been done. Presented method proved to be comparable to the physicians (FF = 90.19 ± 1.01%). Moreover results confirmed a proper algorithm convergence. Automatically segmented area correlated well with manual segmentation for single measurements ([Formula: see text]) and for average measurements ([Formula: see text]) with p = 0.05. The 10-fold cross-validation analysis (FF = 91.37 ± 1.13%) confirmed a good model generalization resulting in practical performance.

Perioperative complications in patients treated with posterior cervical fusion and bilateral cages.

CONTEXT: Posterior cervical cages have recently become available as an alternative to lateral mass fixation in patients undergoing cervical spine surgery. AIMS: The purpose of this study was to quantify the perioperative complications associated with cervical decompression and fusion in patients treated with a posterior cervical fusion (PCF) and bilateral cages. SETTINGS AND DESIGN: A retrospective, multicenter review of prospectively collected data was performed at 11 US centers. SUBJECTS AND METHODS: The charts of 89 consecutive patients with cervical radiculopathy treated surgically at one level with PCF and cages were reviewed. Three cohorts of patients were included standalone primary PCF with cages, circumferential surgery, and patients with postanterior cervical discectomy and fusion pseudarthrosis. Follow-up evaluation included clinical status and pain scale (visual analog scale). STATISTICAL ANALYSIS USED: The Wilcoxon test was used to test the differences for the data. The P level of 0.05 was considered significant. RESULTS: The mean follow-up interval was 7 months (range: 62 weeks - 2 years). The overall postsurgery complication rate was 4.3%. There were two patients with neurological complications (C5 palsy, spinal cord irritation). Two patients had postoperative complications after discharge including one with atrial fibrillation and one with a parietal stroke. After accounting for relatedness to the PCF, the overall complication rate was 3.4%. The average (median) hospital stay for all three groups was 29 h. CONCLUSIONS: The results of our study show that PCF with cages can be considered a safe alternative for patients undergoing cervical spine surgery. The procedure has a favorable overall complication profile, short length of stay, and negligible blood loss.