Responding to Intraoperative Neuromonitoring Changes During Pediatric Coronal Spinal Deformity Surgery

Effect of Spinal Cord Compression and Deformation on Postoperative Neurological Deficits During Spinal Deformity Correction Surgery

Study DesignRetrospective comparative analysis.ObjectiveTo evaluate the impact of the spinal cord deformation rate (SCDR) on postoperative neurological deficits (PNDs) in spinal deformity surgery and to determine the optimal SCDR threshold for risk stratification.MethodsPatients undergoing corrective surgery between October 2010 and March 2022 were included. Spinal cord morphology at the apex was assessed using axial T2-weighted magnetic resonance imaging, categorizing spinal cords into type-A and type-B. Differences between the two groups were analyzed and the odds ratio (OR) for PNDs in patients with type-B was calculated. For patients classified as type-B, univariate analysis was conducted to identify variables, including SCDR, that may influence PNDs risk. Statistically significant variables were further analyzed using multivariate analysis. The receiver operating characteristic (ROC) curve and area under the curve (AUC) analyses were performed to evaluate the discriminative ability of risk factors and determine the optimal cut-off value.ResultsAmong 200 patients included, PNDs occurred in 17 cases (8.5%), predominantly in type-B (15/82 in type-B vs 2/118 in type-A, P < 0.001). Multivariate analysis revealed SCDR as an independent predictor of PNDs (OR = 1.076, P = 0.001). ROC analysis determined an optimal SCDR cutoff of 42.15% (AUC: 0.867), with 82.4% sensitivity, 88.5% specificity, and 98.2% negative predictive value (NPV). SCDR demonstrated superior predictive performance compared to the major Cobb angle (AUC: 0.776) and T-DAR (AUC: 0.769).ConclusionsFor patients undergoing corrective surgery, an SCDR of ≥42.15% serves as a strong predictor of PNDs. Its high NPV effectively excludes low-risk patients, offering improved risk stratification.

Quadripolar Stimulation as an Adjunct to Neuromonitoring in Scoliosis Surgery: A Case Report

CASE

A healthy 13-year-old adolescent girl with a normal spine magnetic resonance imaging underwent posterior spinal fusion for adolescent idiopathic scoliosis (AIS). Before surgery, she had abnormal baseline motor-evoked potentials (MEPs). After technical issues were ruled out, quadripolar stimulation yielded normal baseline MEPs and somatosensory evoked potentials. The surgery was completed without complication, and the patient awoke from surgery without signs of neurological deficits.

CONCLUSION

Quadripolar stimulation with the use of an additional paired anode and cathode is a useful adjunct and should be used in troubleshooting abnormal baseline neuromonitoring in patients with AIS with normal spine imaging undergoing posterior spinal fusion.

The use of skin traction as an intraoperative adjunct for correction during pediatric neuromuscular scoliosis correction

PURPOSE

Intraoperative traction can improve deformity correction during posterior spinal fusion (PSF). This is commonly done with invasive distal femoral or pelvic pins, or traction boots. The novel technique of intraoperative skin traction (ISkinT) avoids risks associated with intraoperative skeletal traction (ISkelT) or hyperlordosis with extended hip position. We aimed to describe ISkinT and assess its safety and efficacy in PSF in non-ambulatory scoliosis.

METHODS

Retrospective review of patients aged 10-21yo who underwent T2-pelvis PSF with ISkinT from 2017 to 2023. Demographics and radiographic measurements were statistically compared to a published cohort that used ISkelT.

RESULTS

42 patients treated with ISkinT were included and compared to 41 patients treated with ISkelT. ISkinT was applied by a cranial attachment and an average of 12% body weight to the pelvis with the hips and knees flexed, using tape-rope-weight system with Trendelenburg assistance. The preop major Cobb was 90°±21° in the ISkinT cohort and 91°±17° in the ISkelT cohort (p = 0.743; d = 0.07), which corrected 75% in ISkinT and 53% in ISkelT (p < 0.0001; d = 1.3). Preop pelvic obliquity averaged 23°± 10° in ISkinT and 34°±14° in ISkelT that corrected 74% in ISkinT and 65% in ISkelT (p < 0.0001; d = 0.95). No intraop or postoperative skin traction-related complications occurred, including neuromonitoring complications (obtained in 88%).

CONCLUSION

In non-ambulatory neuromuscular pediatric scoliosis patients, ISkinT during PSF to the pelvis is a safe and effective technique for deformity correction. There were no associated complications and no difference of corrective capacity for ISkinT compared to ISkelT. ISkinT can be considered for T2-pelvis PSF for pediatric scoliosis.

Does an improvement in cord-level intraoperative neuromonitoring data lead to a reduced risk for postoperative neurologic deficit in spine deformity surgery?

PURPOSE

To determine if an improvement in cord-level intraoperative neuromonitoring (IONM) data following data loss results in a reduced risk for new postoperative motor deficit in pediatric and adult spinal deformity surgery.

METHODS

A consecutive series of 1106 patients underwent spine surgery from 2015 to 2023 by a single surgeon. Cord alerts were defined by Somatosensory-Evoked Potentials (SSEP; warning criteria: 10% increase in latency or > 50% loss in amplitude) and Motor-Evoked Potentials (MEP; warning criteria: 75% loss in amplitude without return to acceptable limits after stimulation up 100 V above baseline level). Timing of IONM loss and recovery, interventions, and baseline/postoperative day 1 (POD1) lower extremity motor scores were analyzed.

RESULTS

IONM Cord loss was noted in 4.8% (53/11,06) of patients and 34% (18/53) with cord alerts had a POD1 deficit compared to preoperative motor exam. MEP and SSEP loss attributed to 98.1% (52/53) and 39.6% (21/53) of cord alerts, respectively. Abnormal descending neurogenic-evoked potential (DNEP) was seen in 85.7% (12/14) and detected 91.7% (11/12) with POD1 deficit. Abnormal wake-up test (WUT) was seen in 38.5% (5/13) and detected 100% (5/5) with POD1 deficit. Most cord alerts occurred during a three-column osteotomy (N = 23/53, 43%); decompression (N = 12), compression (N = 7), exposure (N = 4), and rod placement (N = 14). Interventions were performed in all 53 patients with cord loss and included removing rods/less correction (N = 11), increasing mean arterial pressure alone (N = 10), and further decompression with three-column osteotomy (N = 9). After intervention, IONM data improved in 45(84.9%) patients (Full improvement: N = 28; Partial improvement: 17). For those with full and partial IONM improvement, the POD1 deficit was 10.7% (3/28) and 41.2% (7/17), respectively. For those without any IONM improvement (15.1%, 8/53), 100% (8/8) had a POD1 deficit, P < 0.001.

CONCLUSION

A full or partial improvement in IONM data loss after intraoperative intervention was significantly associated with a lower risk for POD1 deficit with an absolute risk reduction of 89.3% and 58.8%, respectively. All patients without IONM improvement had a POD1 neurologic deficit.

Intra-operative neuromonitoring in paediatric spinal deformity surgery: a retrospective single-centre experience

INTRODUCTION

Intra-operative neuromonitoring including somatosensory evoked potentials, motor evoked potentials, and electromyography, have replaced the Stagnara wake-up test to allow early detection of neurological change during paediatric spinal deformity surgery. It is important for surgeons to recognize alerts triggered by loss of these potentials and act accordingly to prevent iatrogenic neurological damage intra-operatively. This study was conducted to determine the sensitivity and specificity of neuromonitoring alerts in paediatric spinal deformity correction surgery.

METHODS

A retrospective single-centre study of all patients undergoing spinal deformity surgery at a tertiary paediatric centre between 1 January 2017 and 31 December 2020 (inclusive) was conducted. Neuromonitoring alerts were identified through neurophysiology documentation, and these were correlated with neurological deficits documented in the patient record post-operatively.

RESULTS

A total of 399 operations were included in the study, with 147 (35.7%) of these having a motor, or motor and sensory alert triggered. Fifteen (10.2% of alerts) of these patients had a post-operative neurological deficit, compared to seven (2.8% of no alerts) of those that had no neuromonitoring alert. The sensitivity for post-operative neurological deficits not resolving within 3 days was 100%, and the specificity was 65.5%.

CONCLUSION

Intra-operative neuromonitoring is highly sensitive to post-operative neurological deficits lasting longer than 3 days. However, there is still scope for optimization of specificity, with many false positives identified.

Does Spinal Cord Type Predict Intraoperative Neuro-Monitoring Alerts in Scoliosis Correction Surgery? A Systematic Review and Meta-Analysis of Operative and Radiologic Predictors

STUDY DESIGN

Systematic literature review and meta-analysis.

OBJECTIVES

Predicting patient risk of intraoperative neuromonitoring (IONM) alerts preoperatively can aid patient counselling and surgical planning. Sielatycki et al established an axial-MRI-based spinal cord classification system to predict risk of IONM alerts in scoliosis correction surgery. We aim to systematically review the literature on operative and radiologic factors associated with IONM alerts, including a novel spinal cord classification.

METHODS

A systematic review and meta-analysis was performed as per the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) Guidelines. A literature search identifying all observational studies comparing patients with and without IONM alerts was conducted. Suitable studies were included. Patient demographics, radiological measures and operative factors were collected.

RESULTS

11 studies were included including 3040 patients. Relative to type 3 cords, type 1 (OR = .03, CI = .01-.08, P < .00001), type 2 (OR = .08, CI = .03, P <.00001) and all non-type 3 cords (OR = .05, CI = .02-.16, P < .00001) were associated with significantly lower odds of IONM alerts. Significant radiographic measures for IONM alerts included coronal Cobb angle (MD = 10.66, CI = 5.77-15.56, P < .00001), sagittal Cobb angle (MD = 9.27, CI = 3.28-14.73, P = .0009), sagittal deformity angle ratio (SDAR) (MD = 2.76, CI = 1.57-3.96, P < .00001) and total deformity angle ratio (TDAR) (MD = 3.44, CI = 2.27-4.462, P < .00001). Clinically, estimated blood loss (MD = 274.13, CI = -240.03-788.28, P = .30), operation duration (MD = 50.79, CI = 20.58-81.00, P = .0010), number of levels fused (MD = .92, CI = .43-1.41, P = .0002) and number of vertebral levels resected (MD = .43, CI = .01-.84, P = .05) were significantly greater in IONM alert patients.

CONCLUSIONS

This study highlights the relationship of operative and radiologic factors with IONM alerts.

Prospective Validation of the Spinal Cord Shape Classification System in the Prediction of Intraoperative Neuromonitoring Data Loss: Assessing the Risk of Spinal Cord Data Loss During Spinal Deformity Correction

BACKGROUND

The Spinal Cord Shape Classification System (SCSCS) class has been associated with spinal cord monitoring data loss during spinal deformity surgery. The objective of the current study was to prospectively validate the SCSCS as a predictor of spinal cord monitoring data loss during spinal deformity surgery.

METHODS

A prospective cohort study of consecutive patients who were undergoing primary deformity surgery at a single institution from 2018 to 2023 and whose major curve was in the spinal cord region was undertaken. Spinal cord morphology at the apex of the major curve on preoperative axial T2-weighted magnetic resonance imaging was used to categorize patients into 3 spinal cord shape types based on the SCSCS. The primary outcome was intraoperative neuromonitoring (IONM) data loss related to spinal cord dysfunction. Demographics and surgical and radiographic variables were compared between patients with IONM data loss and those without loss. Predictors of IONM loss were determined using bivariate and multivariable logistic regression analyses.

RESULTS

A total of 256 patients (168 adult, 88 pediatric) were included and were separated into 3 SCSCS types: 110 (43.0%) with Type I, 105 (41.0%) with Type II, and 41 (16.0%) with Type III. IONM loss was observed in 30 (11.7%) of the 256 patients, including 7 (6.4%) of 110 with SCSCS Type I, 7 (6.7%) of 105 with Type II, and 16 (39.0%) of 41 with Type III. IONM loss was associated with SCSCS Type III, the preoperative deformity angular ratio, performance of 3-column osteotomies, greater operative time, greater transfusion volume, and greater postoperative sagittal corrections. SCSCS type was the strongest independent predictor of IONM data loss. SCSCS Type III had the greatest odds of IONM loss (odds ratio [OR] = 6.68, 95% confidence interval [CI] = 2.45 to 18.23 compared with Types I and II combined). The overall predictive performance with respect to IONM loss (area under the receiver operating characteristic curve = 0.827) was considered excellent.

CONCLUSIONS

This prospective cohort study of patients undergoing spinal deformity correction confirmed that patients with a Type-III spinal cord shape had greater odds of IONM loss. Inclusion of the SCSCS in preoperative risk stratification and intraoperative management of spinal deformity corrective surgery is recommended.

LEVEL OF EVIDENCE

Prognostic Level II . See Instructions for Authors for a complete description of levels of evidence.

The Effect of Anaemia on Intra-operative Neuromonitoring Following Correction of Large Scoliosis Curves: Two Case Reports

The correction of anemia is important in reversing significant intraoperative bilateral motor-evoked potential (MEP) loss following rod placement for correction of large scoliosis curves. This article presents a retrospective review of intraoperative neuromonitoring (IONM) data, anesthesia records, and medical charts of two patients with significant bilateral MEP changes associated with posterior spinal surgery for deformity correction. A 70 kg 12-year-old and a 44 kg 16-year-old female with main thoracic curves underwent a posterior scoliosis correction with multilevel posterior column osteotomies. Following rod insertion, significant reduction in the bilateral lower extremity MEP occurred in both cases despite mean arterial pressure exceeding 70 mmHg, which was presumed to be due to the scale of the correction attempted in the setting of haemorrhage which rendered the patient acutely anaemic, thus compromising cord vasculature and oxygen delivery. The rods were removed and packed red blood cell transfusions were administered in response to acute anaemia as a result of haemorrhage in both cases. Neither was noted to be anaemic preoperatively. Once the MEP signals improved, the rods were reinserted and correction was attempted, limited by neuromonitoring signals and resistance of the bony anchors to pullout. At closure, the MEPs were near baseline in the first case and >50% of baseline in the second. There were no changes in the somatosensory evoked potential signals in either case. Post-operative neurological function was normal in both patients. Correcting the circulating haemoglobin concentration through blood product resuscitation allowed for safe correction of spinal deformity in two cases with significant bilateral MEP loss following the initial placement of rods.

A Clinical Practice Guideline on the Timing of Surgical Decompression and Hemodynamic Management of Acute Spinal Cord Injury and the Prevention, Diagnosis, and Management of Intraoperative Spinal Cord Injury: Introduction, Rationale, and Scope

STUDY DESIGN

Protocol for the development of clinical practice guidelines following the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) standards.

OBJECTIVES

Acute SCI or intraoperative SCI (ISCI) can have devastating physical and psychological consequences for patients and their families. The treatment of SCI has dramatically evolved over the last century as a result of preclinical and clinical research that has addressed important knowledge gaps, including injury mechanisms, disease pathophysiology, medical management, and the role of surgery. In an acute setting, clinicians are faced with critical decisions on how to optimize neurological recovery in patients with SCI that include the role and timing of surgical decompression and the best strategies for hemodynamic management. The lack of consensus surrounding these treatments has prevented standardization of care across centers and has created uncertainty with respect to how to best manage patients with SCI. ISCI is a feared complication that can occur in the best of hands. Unfortunately, there are no systematic reviews or clinical practice guidelines to assist spine surgeons in the assessment and management of ISCI in adult patients undergoing spinal surgery. Given these limitations, it is the objective of this initiative to develop evidence-based recommendations that will inform the management of both SCI and ISCI. This protocol describes the rationale for developing clinical practice guidelines on (i) the timing of surgical decompression in acute SCI; (ii) the hemodynamic management of acute SCI; and (iii) the prevention, identification, and management of ISCI in patients undergoing surgery for spine-related pathology.

METHODS

Systematic reviews were conducted according to PRISMA standards in order to summarize the current body of evidence and inform the guideline development process. The guideline development process followed the approach proposed by the GRADE working group. Separate multidisciplinary, international groups were created to perform the systematic reviews and formulate the guidelines. All potential conflicts of interest were vetted in advance. The sponsors exerted no influence over the editorial process or the development of the guidelines.

RESULTS

This process resulted in both systematic reviews and clinical practice guidelines/care pathways related to the role and timing of surgery in acute SCI; the optimal hemodynamic management of acute SCI; and the prevention, diagnosis and management of ISCI.

CONCLUSIONS

The ultimate goal of this clinical practice guideline initiative was to develop evidence-based recommendations for important areas of controversy in SCI and ISCI in hopes of improving neurological outcomes, reducing morbidity, and standardizing care across settings. Throughout this process, critical knowledge gaps and future directions were also defined.

Error traps and preventative strategies for adolescent idiopathic scoliosis spinal surgery

Anesthesia for posterior spinal fusion for adolescent idiopathic scoliosis remains one of the most common surgeries performed in adolescents. These procedures have the potential for significant intraprocedural and postoperative complications. The potential for pressure injuries related to prone positioning must be understood and addressed. Additionally, neuromonitoring remains a mainstay for patient care in order to adequately assess patient neurologic integrity and alert the providers to a reversible action. As such, causes of neuromonitoring signal loss must be well understood, and the provider should have a systematic approach to signal loss. Further, anesthetic design must facilitate intraoperative wake-up to allow for a definitive assessment of neurologic function. Perioperative bleeding risk is high in posterior spinal fusion due to the extensive surgical exposure and potentially lengthy operative time, so the provider should undertake strategies to reduce blood loss and avoid coagulopathy. Pain management for adolescents undergoing spinal fusion is also challenging, and inadequate analgesia can delay recovery, impede patient/family satisfaction, increase the risk of chronic postsurgical pain/disability, and lead to prolonged opioid use. Many of the significant complications associated with this procedure, however, can be avoided with intentional and evidence-based approaches covered in this review.

A comparison of three- and two-rod constructs in the correction of severe pediatric scoliosis

Purpose

Managing severe scoliosis is challenging and risky with a significant complication rate regardless of treatment strategy. In this retrospective comparative study, we report our results using a three-rod compared to two-rod construct in the surgical treatment of severe spine deformities to investigate which technique is safer, and which provides superior radiological outcomes.

Methods

Forty-six consecutive patients undergoing posterior spine fusion for scoliosis between 2006 and 2017 were identified in our institutional records. Inclusion criteria were minimum coronal deformity of 90°, age < 18 years at the time of surgery and a minimum 2 years of follow-up. Radiographic and clinical parameters, as well as post-operative complications were compared between the two groups.

Results

There were 21 patients in the three-rod group and 25 in the two-rod group. The mean preoperative major coronal deformity was 100°± 9 and 102°± 10 in the three-rod and two-rod, respectively (p = 0.6). The average major curve correction was 51% and 59% in three-rod and two-rod groups, respectively (p = 0.03). The post-operative thoracic kyphosis was 30°± 11 and 21°± 12 in the three-rod and the two-rod groups, respectively (p = 0.01). The surgical time was 476 ± 52 and 387 ± 84 min in three-rod and two-rod, respectively (p < 0.01). One patient in the two-rod cohort showed permanent post-operative sensory deficit. There were three unplanned returns to operating theater in the two-rod group.

Conclusions

Coronal correction was better with two-rod, whereas sagittal balance was superior with three-rod. Both techniques achieved balanced spine treating severe scoliosis. The two-rod technique was associated with a higher likelihood of requiring revision surgery.

Level of evidence

level 3.

Intraoperative neuromonitoring in non-idiopathic pediatric scoliosis operated with minimally fusionless procedure: A series of 290 patients

BACKGROUND

One of the worst complications of surgery for spinal deformity is postoperative neurological deficit. Multimodal intraoperative neuromonitoring (IONM) can be used to detect impending neurological injuries. This study aimed to analyze IONM in non-idiopathic scoliosis using a minimally invasive fusionless surgical technique.

METHODS

This retrospective, single-center study was performed from 2014 to 2018. Patients with non-idiopathic scoliosis who underwent a minimally invasive fusionless procedure and had at least 2 years of follow-up were included. IONM was performed using a neurophysiological monitoring work station with somatosensory evoked potentials (SSEP) and neurogenic mixed evoked potentials (NMEP).

RESULTS

A total of 290 patients were enrolled. The mean age at surgery was 12.9±3 years. The main etiology was central nervous system (CNS) disorders (n=139, 48%). Overall, 35 alerts (11%) in the SSEP and 10 (7%) in the NMEP occurred. There were two neurological deficits with total recovery after 6 months. There were no false negatives in either SSEP or NMEP, although there was one false positive in SSEP and two false positives for NMEP in the group without signal recovery. There was no significant relationship between the incidence of SSEP or NMEP loss and age, body mass index (BMI), number of rods used, upper instrumented vertebrae (p=0.36), lower instrumented vertebrae, or type of surgery. A preoperative greater Cobb angle was associated with a significantly higher risk of NMEP loss (p=0.02). In CNS patients, a higher BMI was associated with a statistically significant risk of NMEP loss (p=0.004). The use of a traction table was associated with a higher risk of signal loss (p=0.0005).

CONCLUSION

A preoperative higher Cobb angle and degree of correction were associated with a significant risk of NMEP loss. In CNS scoliosis, a higher BMI was associated with a significant risk of NMEP loss. The use of a traction table was associated with a higher risk of signal loss.

Establishing consensus: determinants of high-risk and preventative strategies for neurological events in complex spinal deformity surgery

PURPOSE

To establish expert consensus on various parameters that constitute elevated risk during spinal deformity surgery and potential preventative strategies that may minimize the risk of intraoperative neuromonitoring (IONM) events and postoperative neurological deficits.

METHODS

Through a series of surveys and a final virtual consensus meeting, the Delphi method was utilized to establish consensus among a group of expert spinal deformity surgeons. During iterative rounds of voting, participants were asked to express their agreement (strongly agree, agree, disagree, strongly disagree) to include items in a final set of guidelines. Consensus was defined as ≥ 80% agreement among participants. Near-consensus was ≥ 60% but < 80% agreement, equipoise was ≥ 20% but < 60%, and consensus to exclude was < 20%.

RESULTS

Fifteen of the 15 (100%) invited expert spinal deformity surgeons agreed to participate. There was consensus to include 22 determinants of high-risk (8 patient factors, 8 curve and spinal cord factors, and 6 surgical factors) and 21 preventative strategies (4 preoperative, 14 intraoperative, and 3 postoperative) in the final set of best practice guidelines.

CONCLUSION

A resource highlighting several salient clinical factors found in high-risk spinal deformity patients as well as strategies to prevent neurological events was successfully created through expert consensus. This is intended to serve as a reference for surgeons and other clinicians involved in the care of spinal deformity patients.

LEVEL OF EVIDENCE

Level V.

Development of consensus-based best practice guidelines for response to intraoperative neuromonitoring events in high-risk spinal deformity surgery

PURPOSE

To expand on previously described intraoperative aids by developing consensus-based best practice guidelines to optimize the approach to intraoperative neuromonitoring (IONM) events associated with "high-risk" spinal deformity surgery.

METHODS

Consensus was established among a group of experienced spinal deformity surgeons by way of the Delphi method. Through a series of iterative surveys and a final virtual consensus meeting, participants expressed their agreement (strongly agree, agree, disagree, and strongly disagree) with various items. Consensus was defined as ≥ 80% agreement ("strongly agree" or "agree"). Near-consensus was defined as ≥ 60% but < 80%. Equipoise was ≥ 20% but < 60%, and consensus to exclude was < 20%.

RESULTS

15 out of 15 (100%) invited surgeons agreed to participate. Final consensus supported inclusion of 105 items (53 in Response Algorithm, 13 in Ongoing Consideration of Etiology, 31 in Real-Time Data Scenarios, 8 in Patterns of IONM Loss), which were organized into a final set of best practice guidelines.

CONCLUSION

Detailed consensus-based best practice guidelines and aids were successfully created with the intention to help organize and direct the surgical team in exploring and responding to neurological complications during high-risk spinal deformity surgery.

LEVEL OF EVIDENCE

Level V.

Natural language processing for automated surveillance of intraoperative neuromonitoring in spine surgery

We sought to develop natural language processing (NLP) methods for automated detection and characterization of neuromonitoring documentation from free-text operative reports in patients undergoing spine surgery. We included 13,718 patients who received spine surgery at two tertiary academic medical centers between December 2000 - December 2020. We first validated a rule-based NLP method for identifying operative reports containing neuromonitoring documentation, comparing performance to standard administrative codes. We then trained a deep learning model in a subset of 993 patients to characterize neuromonitoring documentation and identify events indicating change in status or difficulty establishing baseline signals. Performance of the deep learning model was compared to gold-standard manual chart review. In our patient population, 3,606 (26.3%) patients had neuromonitoring documentation identified using NLP. Our NLP method identified notes containing neuromonitoring documentation with an F1-score of 1.0, surpassing performance of standard administrative codes which had an F1-score of 0.64. In the subset of 993 patients used for training, validation, and testing a deep learning model, the prevalence of change in status was 6.5% and difficulty establishing neuromonitoring baseline signals was 6.6%. The deep learning model had an F1-score = 0.80 and AUC-ROC = 1.0 for identifying change in status, and an F1-score = 0.80 and AUC-ROC = 0.97 for identifying difficulty establishing baseline signals. Compared to gold standard manual chart review, our methodology has greater efficiency for identifying infrequent yet important types of neuromonitoring documentation. This method may facilitate large-scale quality improvement initiatives that require timely analysis of a large volume of EHRs.

Perioperative blood conservation strategies for pediatric scoliosis surgery

PURPOSE

Many pediatric patients with severe scoliosis requiring surgery have baseline anemia. Pediatric scoliosis fusion surgery is associated with perioperative blood loss requiring transfusion. As such, many patients in this surgical population could benefit from a perioperative blood conservation program.

METHODS

Here we present a narrative review of perioperative blood conservation strategies for pediatric scoliosis surgery involving nurses, transfusion medicine physicians, anesthesiologists, surgeons, dieticians, perfusionists and neurophysiologists spanning the pre-, intra- and postoperative phases of care.

RESULTS

The review highlights how perioperative blood conservation strategies, have the potential to minimize exposures to exogenous blood products. Further, we describe a relevant example of blood conservation related to the care of a Jehovah's Witness patient undergoing staged scoliosis repair. Lastly, we outline areas which would benefit from clinical studies to further elucidate perioperative blood conservation interventions and their outcomes relevant to pediatric scoliosis surgery patients.

CONCLUSION

Interdisciplinary communication and meticulous blood conservation strategies are proving to be a means of reducing if not eliminating the need for allogeneic blood products for surgical correction of pediatric scoliosis.

The use of three rods in correcting severe scoliosis

PURPOSE

The three-rod technique, utilising a short apical concavity rod is an option to achieve controlled correction in severe scoliosis. We describe this technique, the complications encountered, and the long-term outcomes.

METHOD

All paediatric patients who had at least 2 years follow-up after undergoing corrective surgery for scoliosis ≥ 100° using 3 parallel rods were included. Radiographs were assessed to evaluate the correction and clinical records examined for any loss of correction, complications, revision procedures or neuromonitoring events.

RESULTS

Twenty-five patients met the inclusion criteria. Four underwent prior anterior fusion to prevent crankshaft phenomenon. The mean angle of the deformity was 112.0° (range 100.3-137.1). Mean maximal kyphosis was 48.8° (range 11.4-78.8°) and mean curve flexibility 4.4% (range 0-37.0%). Intraoperative traction achieved an average of 70.4% (95% CI 56.6-84.1%). Nine patients (39%) showed a reduction in MEPs during definitive surgery. All returned to within 75% of baseline by the end of surgery. All patients had normal postoperative neurology. One patient underwent removal of hardware for late infection. The mean overall Cobb correction was 55.7° (95% CI 50.2-61.2°), equating to 50.2% (95% CI 44.9-55.4%) of the mean initial deformity. Thoracic kyphosis reduced by a mean of 18.2° (95% CI 12.8-23.6°).

CONCLUSION

Our series suggests that three-rod constructs are able to safely and effectively achieve 50% correction of severe scoliosis.

Severe hypotension with loss of motor evoked potentials during cervical surgery prompting immediate cardiovascular resuscitation

Background:

Intraoperative neuromonitoring (IONM) is a well-established adjunct to spinal surgery to ensure safety of the neural elements.IONM has extremely high sensitivity and specificity for impending neurologic damage. In very rare instances, hypoperfusion of the cord may lead to a loss of IONM modalities that may be reversed if blood pressure issues responsible for the drop out of potentials are immediately addressed.

Case Description:

The authors describe a case in which IONM documented hypoperfusion of the cord intraoperatively due to hypotension. Recognition of this problem and reversal of the hypotension resulted in normalization of postoperative function.

Conclusion:

The use of IONM allowed for quick recognition of an impending neurological insult during spinal deformity surgery. Prompt response to signaling changes allowed for the correction of hypotension and favorable neurologic outcome.

Intermittent and Transient Hypotension-related Anterior Cord Syndrome following Elective Cervical Spine Surgery: A Case Report

Introduction:

Anterior cord syndrome (ACS) is a type of incomplete spinal cord injury caused by either direct compression of the anterior spinal cord, or by ischemia of the anterior spinal artery. This phenomenon has neither been described transiently nor intraoperatively.

Case Report:

We describe the case of a 61-year-old male who developed intermittent and transient anterior spinal cord syndrome secondary to hypotension related hypoperfusion of the anterior spinal artery after elective cervical spine surgery. Through close blood pressure monitoring and intensive care unit support, the patient regained full neurological recovery.

Conclusion:

Anterior spinal cord syndrome is a rare condition affecting the anterior 2/3 of the spinal cord, resulting in incomplete paralysis. Blood flow can be disrupted through the anterior spinal artery, either through thrombosis or hypotension. We describe our rare case so that surgeons may recognize this potentially devastating condition.

Temporary treatment with magnetically controlled growing rod for surgical correction of severe adolescent idiopathic thoracic scoliosis greater than 100°

INTRODUCTION

Correction of severe idiopathic scoliosis poses surgical challenges. Treatment options entail anterior and/or posterior release, Halo-gravity traction (HGT) and three-column osteotomies (3CO). The authors report results with a novel technique of temporary short-term magnetically controlled growing rod (MCGR) as part of a posterior-only strategy to treat severe idiopathic major thoracic curves (MTC).

METHODS

Seven patients with MTC > 100° treated with temporary MCGR were included. Mean age was 15 years. Preoperative MTC was av. 118° and TC-flexibility av. 19.8%. Patients underwent posterior instrumentation, periapical release using advanced Ponte osteotomies, segmental insertion of pedicle screws and a single MCGR. After av. 14 days, the second surgery was performed with removal of MCGR and final correction and fusion. The spinal height from lowest instrumented vertebra (LIV) to T1 was measured. MTC-correction and scoliosis correction index (SCI) were calculated.

RESULTS

No patient suffered a major complication or neurologic deficit. Instrumentation was from T2 to L3 or L4. This kind of staged surgery achieved a correction of postop MTC to av. 39°, MTC-correction 67% and SCI of av. 4.3. Spinal height T1-LIV increased from preoperative av. 288 mm to postoperative av. 395 mm indicating an increase of > 10 cm.

CONCLUSION

This is the first series of AIS patients that had temporary MCGR to treat severe thoracic scoliosis. A staged protocol including internal temporary distraction with MCGR after posterior release and definitive correction resulted in large MTC-correction and restoration of trunk height. Results indicate that technique has the potential to reduce the necessity for HGT and high-risk 3CO for the correction of severe scoliosis.

Neurophysiologic Intraoperative Monitoring for Spine Surgery: A Practical Guide From Past to Present

Intraoperative neuromonitoring was introduced in the second half of the 20th century with the goal of preventing patient morbidity for patients undergoing complex operations of the central and peripheral nervous system. Since its early use for scoliosis surgery, the growth and utilization of IOM techniques expanded dramatically over the past 50 years to include spinal tumor resection and evaluation of cerebral ischemia. The importance of IOM has been broadly acknowledged, and in 1989, the American Academy of Neurology (AAN) released a statement that the use of SSEPs should be standard-of-care during spine surgery. In 2012, both the AAN and the American Clinical Neurophysiology Society (ACNS) recommended that: "Intraoperative monitoring (IOM) using SSEPs and transcranial MEPs be established as an effective means of predicting an increased risk of adverse outcomes, such as paraparesis, paraplegia, and quadriplegia, in spinal surgery." With a multimodal approach that combines SSEPs, MEPs, and sEMG with tEMG and D waves, as appropriate, sensitivity and specificity can be maximized for the diagnosis of reversible insults to the spinal cord, nerve roots, and peripheral nerves. As with most patient safety efforts in the operating room, IOM requires contributions from and communication between a number of different teams. This comprehensive review of neuromonitoring techniques for surgery on the central and peripheral nervous system will highlight the technical, surgical and anesthesia factors required to optimize outcomes. In addition, this review will discuss important trouble shooting measures to be considered when managing ION changes concerning for potential injury.