Timing of intraoperative neurophysiological monitoring (IONM) recovery and clinical recovery after termination of pediatric spinal deformity surgery due to loss of IONM signals.

BACKGROUND CONTEXT: Intraoperative neurophysiological monitoring (IONM) is used to reduce the risk of spinal cord injury during pediatric spinal deformity surgery. Significant reduction and/or loss of IONM signals without immediate recovery may lead the surgeon to acutely abort the case. The timing of when monitorable signals return remains largely unknown. PURPOSE: The goal of this study was to investigate the correlation between IONM signal loss, clinical examination, and subsequent normalization of IONM signals after aborted pediatric spinal deformity surgery to help determine when it is safe to return to the operating room. STUDY DESIGN/SETTING: This is a multicenter, multidisciplinary, retrospective study of pediatric patients (<18 years old) undergoing spinal deformity surgery whose surgery was aborted due to a significant reduction or loss of IONM potentials. PATIENT SAMPLE: Sixty-six patients less than 18 years old who underwent spinal deformity surgery that was aborted due to IONM signal loss were enrolled into the study. OUTCOME MEASURES: IONM data, operative reports, and clinical examinations were investigated to determine the relationship between IONM loss, clinical examination, recovery of IONM signals, and clinical outcome. METHODS: Information regarding patient demographics, deformity type, clinical history, neurologic and ambulation status, operative details, IONM information (eg, quality of loss [SSEPs, MEPs], laterality, any recovery of signals, etc.), intraoperative wake-up test, postoperative neurologic exam, postoperative imaging, and time to return to the operating were all collected. All factors were analyzed and compared with univariate and multivariate analysis using appropriate statistical analysis. RESULTS: Sixty-six patients were enrolled with a median age of 13 years [IQR 11-14], and the most common sex was female (42/66, 63.6%). Most patients had idiopathic scoliosis (33/66, 50%). The most common causes of IONM loss were screw placement (27/66, 40.9%) followed by rod correction (19/66, 28.8%). All patients had either complete bilateral (39/66, 59.0%), partial bilateral (10/66, 15.2%) or unilateral (17/66, 25.8%) MEP loss leading to termination of the case. Overall, when patients were returned to the operating room 2 weeks postoperatively, nearly 75% (40/55) had monitorable IONM signals. Univariate analysis demonstrated that bilateral SSEP loss (p=.019), bilateral SSEP and MEP loss (p=.022) and delayed clinical neurologic recovery (p=.008) were significantly associated with having unmonitorable IONM signals at repeat surgery. Multivariate regression analysis demonstrated that delayed clinical neurologic recovery (> 72 hours) was significantly associated with unmonitorable IONM signals when returned to the operating room (p=.006). All patients ultimately made a full neurologic recovery. CONCLUSIONS: In children whose spinal deformity surgery was aborted due to intraoperative IONM loss, there was a strong correlation between combined intraoperative SSEP/MEP loss, the magnitude of IONM loss, the timing of clinical recovery, and the time of electrophysiological IONM recovery. The highest likelihood of having a prolonged postoperative neurological deficit and undetectable IONM signals upon return to the OR occurs with bilateral complete loss of SSEPs and MEPs.

Incidence, mechanism, and protective strategies for 2-year pelvic fixation failure after adult spinal deformity surgery with a minimum six-level fusion.

OBJECTIVE: The purpose of this study was to determine the incidence, mechanism, and potential protective strategies for pelvic fixation failure (PFF) within 2 years after adult spinal deformity (ASD) surgery. METHODS: Data for ASD patients (age ≥ 18 years, minimum of six instrumented levels) with pelvic fixation (S2-alar-iliac [S2AI] and/or iliac screws) with a minimum 2-year follow-up were consecutively collected (2015-2019). Patients with prior pelvic fixation were excluded. PFF was defined as any revision to pelvic screws, which may include broken rods across the lumbosacral junction requiring revision to pelvic screws, pseudarthrosis across the lumbosacral junction requiring revision to pelvic screws, a broken or loose pelvic screw, or sacral/iliac fracture. Patient information including demographic data and health history (age, sex, BMI, smoking status, American Society of Anesthesiologists score, osteoporosis), operative (total instrumented levels [TIL], three-column osteotomy [3CO], interbody fusion), screw (iliac, S2AI, length, diameter), rod (diameter, kickstand), rod pattern (number crossing lumbopelvic junction, lowest instrumented vertebra [LIV] of accessory rod[s], lateral connectors, dual-headed screws), and pre- and postradiographic (lumbar lordosis, pelvic incidence, pelvic tilt, major Cobb angle, lumbosacral fractional curve, C7 coronal vertical axis [CVA], T1 pelvic angle, C7 sagittal vertical axis) parameters was collected. All rods across the lumbosacral junction were cobalt-chrome. All iliac and S2AI screws were closed-headed tulips. Both univariate and multivariate analyses were performed to determine risk factors for PFF. RESULTS: Of 253 patients (mean age 58.9 years, mean TIL 13.6, 3CO 15.8%, L5-S1 interbody 74.7%, mean pelvic screw diameter/length 8.6/87 mm), the 2-year failure rate was 4.3% (n = 11). The mechanisms of failure included broken rods across the lumbosacral junction (n = 4), pseudarthrosis across the lumbosacral junction requiring revision to pelvic screws (n = 3), broken pelvic screw (n = 1), loose pelvic screw (n = 1), sacral/iliac fracture (n = 1), and painful/prominent pelvic screw (n = 1). A higher number of rods crossing the lumbopelvic junction (mean 3.8 no failure vs 2.9 failure, p = 0.009) and accessory rod LIV to S2/ilium (no failure 54.2% vs failure 18.2%, p = 0.003) were protective for failure. Multivariate analysis demonstrated that accessory rod LIV to S2/ilium versus S1 (OR 0.2, p = 0.004) and number of rods crossing the lumbar to pelvis (OR 0.15, p = 0.002) were protective, while worse postoperative CVA (OR 1.5, p = 0.028) was an independent risk factor for failure. CONCLUSIONS: The 2-year PFF rate was low relative to what is reported in the literature, despite patients undergoing long fusion constructs for ASD. The number of rods crossing the lumbopelvic junction and accessory rod LIV to S2/ilium relative to S1 alone likely increase construct stiffness. Residual postoperative coronal malalignment should be avoided to reduce PFF.

How common is acute pelvic fixation failure after adult spine surgery? A single-center study of 358 patients.

OBJECTIVE: There is a paucity of literature on pelvic fixation failure after adult spine surgery in the early postoperative period. The purpose of this study was to determine the incidence of acute pelvic fixation failure in a large single-center study and to describe the lessons learned. METHODS: The authors performed a retrospective review of adult (≥ 18 years old) patients who underwent spinal fusion with pelvic fixation (iliac, S2-alar-iliac [S2AI] screws) at a single academic medical center between 2015 and 2020. All patients had a minimum of 3 instrumented levels. The minimum follow-up was 6 months after the index spine surgery. Patients with prior pelvic fixation were excluded. Acute pelvic fixation failure was defined as revision of the pelvic screws within 6 months of the primary surgery. Patient demographics and operative, radiographic, and rod/screw parameters were collected. All rods were cobalt-chrome. All iliac and S2AI screws were closed-headed screws. RESULTS: In 358 patients, the mean age was 59.5 ± 13.6 years, and 64.0% (n = 229) were female. The mean number of instrumented levels was 11.5 ± 5.5, and 79.1% (n = 283) had ≥ 6 levels fused. Three-column osteotomies were performed in 14.2% (n = 51) of patients, and 74.6% (n = 267) had an L5-S1 interbody fusion. The mean diameter/length of pelvic screws was 8.5/86.6 mm. The mean number of pelvic screws was 2.2 ± 0.5, the mean rod diameter was 6.0 ± 0 mm, and 78.5% (n = 281) had > 2 rods crossing the lumbopelvic junction. Accessory rods extended to S1 (32.7%, n = 117) or S2/ilium (45.8%, n = 164). Acute pelvic fixation failure occurred in 1 patient (0.3%); this individual had a broken S2AI screw near the head-neck junction. This 76-year-old woman with degenerative lumbar scoliosis and chronic lumbosacral zone 1 fracture nonunion had undergone posterior instrumented fusion from T10 to pelvis with bilateral S2AI screws (8.5 × 90 mm); i.e., transforaminal lumbar interbody fusion L4-S1. The patient had persistent left buttock pain postoperatively, with radiographically confirmed breakage of the left S2AI screw 68 days after surgery. Revision included instrumentation removal at L2-pelvis and a total of 4 pelvic screws. CONCLUSIONS: The acute pelvic fixation failure rate was exceedingly low in adult spine surgery. This rate may be the result of multiple factors including the preference for multirod (> 2), closed-headed pelvic screw constructs in which large-diameter long screws are used. Increasing the number of rods and screws at the lumbopelvic junction may be important factors to consider, especially for patients with high risk for nonunion.

Surgeon-Delivered Nerve Block for Reduction of Perioperative Pain and Opioid Use After Lumbosacral Spine Surgery.

This cohort study compares postoperative pain scores, opioid use, and length of hospital stay among adults undergoing noninstrumented lumbosacral surgery who received x-ray­guided dorsal ramus block vs those who did not.

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.

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.

Best Practice Guidelines for Assessment and Management of Osteoporosis in Adult Patients Undergoing Elective Spinal Reconstruction.

STUDY DESIGN: Expert consensus study. OBJECTIVE: This expert panel was created to establish best practice guidelines to identify and treat patients with poor bone health prior to elective spinal reconstruction. SUMMARY OF BACKGROUND DATA: Currently, no guidelines exist for the management of osteoporosis and osteopenia in patients undergoing spinal reconstructive surgery. Untreated osteoporosis in spine reconstruction surgery is associated with higher complications and worse outcomes. METHODS: A multidisciplinary panel with 18 experts was assembled including orthopedic and neurological surgeons, endocrinologists, and rheumatologists. Surveys and discussions regarding the current literature were held according to Delphi method until a final set of guidelines was created with over 70% consensus. RESULTS: Panelists agreed that bone health should be considered in every patient prior to elective spinal reconstruction. All patients above 65 and those under 65 with particular risk factors (chronic glucocorticoid use, high fracture risk or previous fracture, limited mobility, and eight other key factors) should have a formal bone health evaluation prior to undergoing surgery. DXA scans of the hip are preferable due to their wide availability. Opportunistic CT Hounsfield Units of the vertebrae can be useful in identifying poor bone health. In the absence of contraindications, anabolic agents are considered first line therapy due to their bone building properties as compared with antiresorptive medications. Medications should be administered preoperatively for at least 2 months and postoperatively for minimum 8 months. CONCLUSION: Based on the consensus of a multidisciplinary panel of experts, we propose best practice guidelines for assessment and treatment of poor bone health prior to elective spinal reconstructive surgery. Patients above age 65 and those with particular risk factors under 65 should undergo formal bone health evaluation. We also established guidelines on perioperative optimization, utility of various diagnostic modalities, and the optimal medical management of bone health in this population.Level of Evidence: 5.

A new modular radiographic classification of adult idiopathic scoliosis as an extension of the Lenke classification of adolescent idiopathic scoliosis.

PURPOSE: To propose and test the reliability of a radiographic classification system for adult idiopathic scoliosis. METHODS: A three-component radiographic classification for adult idiopathic scoliosis consisting of curve type, a lumbosacral modifier, and a global alignment modifier is presented. Twelve spine surgeons graded 30 pre-marked cases twice, approximately 1 week apart. Case order was randomized between sessions. RESULTS: The interrater reliability (Fleiss' kappa coefficient) for curve type was 0.660 and 0.798, for the lumbosacral modifier 0.944 and 0.965, and for the global alignment modifier 0.922 and 0.916, for round 1 and 2 respectively. Mean intrarater reliability was 0.807. CONCLUSIONS: This new radiographic classification of adult idiopathic scoliosis maintains the curve types from the Lenke classification and introduces the lumbosacral and global alignment modifiers. The reliability of the lumbosacral modifier and global alignment modifier shows near perfect agreement, and sets the foundation for further studies to validate the reliability, utility, and applicability of this classification system.

Uncertainty in the Relationship Between Sagittal Alignment and Patient-Reported Outcomes.

BACKGROUND: Previous studies have reported correlations and precise quantitative relationships between sagittal alignment and health-related quality-of-life (HRQOL) scores. These studies have not reported the extent of uncertainty in these relationships. OBJECTIVE: To explore the uncertainty in the overall relationships between sagittal alignment and HRQOL and in the predictions of individual patient pain and disability. METHODS: A retrospective analysis of all new adult patients with long-cassette radiographs and complete outcomes questionnaires presenting to the senior author from 2012 to 2014 was performed. Univariable maximum a posteriori linear regression analyses using Bayesian methods were performed. High-density probability intervals for mean regression relationships and for individual values were calculated using minimally informative prior distributions. RESULTS: A total of 134 patients satisfied inclusion criteria and were included. For Oswestry Disability Index (ODI) vs pelvic incidence-lumbar lordosis (LL), the 90% high-density probability interval ranged from -0.04 to 0.23, indicating that both the magnitude and direction of the relationship were uncertain. For both ODI vs sagittal vertical axis and ODI vs LL, there was uncertainty in the magnitude of the slope. Wide regions of uncertainty were also seen for predicting individual patient scores. CONCLUSION: We report the previously unpublished degree of uncertainty in the mean quantitative relationships between radiographic sagittal alignment and patient-reported outcomes and in individual patient outcomes scores. Based on these results, establishing treatment thresholds or predicting an individual's outcome is unreliable. Further research efforts should be focused on developing multilevel hierarchical models incorporating parameter uncertainty and heterogeneous effects.

Cost-Effectiveness in Adult Spinal Deformity Surgery.

The complexity and heterogeneity of adult spinal deformity (ASD) creates significant difficulties in performing high-quality, complete economic analyses. For the same reasons, however, such studies are immensely valuable to clinicians and health policy experts. There has been a paradigm shift towards value-based healthcare provision and as such, there is an increasing focus on demonstrating not just the value ASD surgery, but the provision of care at large. Health-related quality of life measures are an important tool for assessing value of an intervention and its effect on a quality-adjusted life year (QALY). Currently, there are no definitive criteria in regard to assigning the appropriate value to a QALY. A general accepted threshold discussed in literature is $100 000 per QALY gained. However, this figure may be variable across populations, and may not necessarily be applicable in today's economy, or in all healthcare economies. Fundamentally, an effective treatment method may be associated with a high upfront cost, however, if durable, will be cost-effective over time.The emphasis on carotid endarterectomy and CUA in the field of adult spine deformity is relatively recent; therefore, there is a limited amount of data on cost-effectiveness analyses. Continued efforts with emphasis on value-based outcomes are needed with long-term follow-up studies.

Topical vancomycin to reduce surgical-site infections in neurosurgery: Study protocol for a multi-center, randomized controlled trial.

Surgical-site infections (SSIs) account for 20% of all healthcare-associated infections, are the most common nosocomial infection among surgical patients, and are a focus of quality improvement initiatives. Despite implementation of many quality care measures (e.g. prophylactic antibiotics), SSIs remain a significant cause of morbidity, mortality, and economic burden, particularly in the field of neurosurgery. Topical vancomycin is increasingly utilized in instrumented spinal and cardiothoracic procedures, where it has been shown to reduce the risk of SSIs. However, a randomized controlled trial assessing its efficacy in the general neurosurgical population has yet to be done. The principle aim of "Topical Vancomycin for Neurosurgery Wound Prophylaxis" (NCT02284126) is to determine whether prophylactic, topical vancomycin reduces the risk of SSIs in the adult neurosurgical population. This prospective, multicenter, patient-blinded, randomized controlled trial will enroll patients to receive the standard of care plus topical vancomycin, or the standard of care alone. The primary endpoint of this study is a SSI by postoperative day (POD) 30. Patients must be over 18years of age. Patients are excluded for renal insufficiency, vancomycin allergy, and some ineligible procedures. Univariate analysis and logistic regression will determine the effect of topical vancomycin on SSIs at 30days. A randomized controlled trial is needed to determine the efficacy of this treatment. Results of this trial are expected to directly influence the standard of care and prevention of SSIs in neurosurgical patients.

Temporary occipital fixation in young children with severe cervical-thoracic spinal deformity.

OBJECTIVE The long-term effects of instrumentation and fusion of the occipital-cervical-thoracic spine on spinal growth in young children are poorly understood. To mitigate the effects of this surgery on the growing pediatric spine, the authors report a novel technique used in 4 children with severe cervical-thoracic instability. These patients underwent instrumentation from the occiput to the upper thoracic region for stabilization, but without bone graft at the craniovertebral junction (CVJ). Subsequent surgery was then performed to remove the occipital instrumentation, thereby allowing further growth and increased motion across the CVJ. METHODS Three very young children (15, 30, and 30 months old) underwent occipital to thoracic posterior segmental instrumentation due to cervical or upper thoracic dislocation, progressive kyphosis, and myelopathy. The fourth child (10 years old) underwent similar instrumentation for progressive cervical-thoracic scoliosis. Bone graft was placed at and distal to C-2 only. After follow-up CT scans demonstrated posterior arthrodesis without unintended fusion from the occiput to C-2, 3 patients underwent removal of the occipital instrumentation. RESULTS Follow-up cervical spine flexion/extension radiographs demonstrated partial restoration of motion at the CVJ. One patient has not had the occipital instrumentation removed yet, because only 4 months have elapsed since her operation. CONCLUSIONS Temporary fixation to the occiput provides increased biomechanical stability for spinal stabilization in young children, without permanently eliminating motion and growth at the CVJ. This technique can be considered in children who require longer instrumentation constructs for temporary stabilization, but who only need fusion in more limited areas where spinal instability exists.

ACR Appropriateness Criteria Myelopathy.

Patients presenting with myelopathic symptoms may have a number of causative intradural and extradural etiologies, including disc degenerative diseases, spinal masses, infectious or inflammatory processes, vascular compromise, and vertebral fracture. Patients may present acutely or insidiously and may progress toward long-term paralysis if not treated promptly and effectively. Noncontrast CT is the most appropriate first examination in acute trauma cases to diagnose vertebral fracture as the cause of acute myelopathy. In most nontraumatic cases, MRI is the modality of choice to evaluate the location, severity, and causative etiology of spinal cord myelopathy, and predicts which patients may benefit from surgery. Myelopathy from spinal stenosis and spinal osteoarthritis is best confirmed without MRI intravenous contrast. Many other myelopathic conditions are more easily visualized after contrast administration. Imaging performed should be limited to the appropriate spinal levels, based on history, physical examination, and clinical judgment. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every three years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals, and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Health economic studies: an introduction to cost-benefit, cost-effectiveness, and cost-utility analyses.

STUDY DESIGN: Narrative overview. OBJECTIVE: To provide clinicians with a basic understanding of economic studies, including cost-benefit, cost-effectiveness, and cost-utility analyses. SUMMARY OF BACKGROUND DATA: As decisions regarding public health policy, insurance reimbursement, and patient care incorporate factors other than traditional outcomes such as satisfaction or symptom resolution, health economic studies are increasingly prominent in the literature. This trend will likely continue, and it is therefore important for clinicians to have a fundamental understanding of the common types of economic studies and be able to read them critically. In this brief article, the basic concepts of economic studies and the differences between cost-benefit, cost-effectiveness, and cost-utility studies are discussed. METHODS: An overview of the field of health economic analysis is presented. RESULTS: Cost-benefit, cost-effectiveness, and cost-utility studies all integrate cost and outcome data into a decision analysis model. These different types of studies are distinguished mainly by the way in which outcomes are valued. Obtaining accurate cost data is often difficult and can limit the generalizability of a study. CONCLUSION: With a basic understanding of health economic analysis, clinicians can be informed consumers of these important studies.

ACR appropriateness criteria management of vertebral compression fractures.

This is an updated review of management of vertebral compression fracture for both benign osteoporotic and malignant causes. Vertebral compression fracture radiologic imaging evaluation is discussed. A literature review is provided of current indications for vertebral augmentation with percutaneous vertebroplasty and kyphoplasty as well as medical management. Limitations and potential benefits of these procedures are discussed. Variant tables describing various clinical situations are also provided to assist in determining appropriate use of these treatments for patient care. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 3 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to formulate recommendations for imaging or treatment.

Measuring clinical practice: science and methods.

The routine practice of neurosurgery generates a large amount of clinical data. The structured, systematic capture of this information using clinical registries or other rigorously designed observational studies can yield useful evidence to help improve the care of patients. Registries in particular can be designed to measure outcomes in real-world clinical settings and to study differences in outcomes between subgroups. This information can help clinicians to advise patients regarding their treatment options. To provide valid, generalizable evidence, however, registries and other observational studies must be designed and conducted with a rigor similar to that of randomized clinical trials. Neurosurgeons with a basic understanding of the potential advantages and pitfalls of nonrandomized trials and the methods of statistical analysis will be able to assess the quality of clinical data and to incorporate the findings appropriately into their patients' care.