Spinal Deformity Cases Research Articles

An Inter- and Intra-Rater Agreement Assessment of Two Novel Classification Systems for Coronal Imbalance in Adult Scoliosis and Spine Deformity.

Coronal malalignment is a common feature of adult spinal deformity, and accurate classification is essential for diagnosis and treatment planning. However, variations in interpretation among clinicians can impact classification consistency. By assessing the reliability and applicability of these systems across different medical experts, this study seeks to establish a standardized approach to enhance clinical outcomes. This study aimed to evaluate the inter- and intra-observer agreement of two classification systems for coronal malalignment in adult spinal deformity patients, as proposed by Qiu etal. and Obeid etal. We analyzed 70 cases of adult spinal deformity collected between January 1, 2010, and April 20, 2023, using the classification systems proposed by Qiu etal. and Obeid etal. To assess inter- and intra-rater agreement, the same group of researchers re-evaluated all cases in a random order after a 4-week interval. We used the kappa statistic (κ) for inter- and intra-rater agreement assessment. Qiu's classification system: Inter-rater agreement: Substantial agreement (κ = 0.76; 95% CI: 0.72-0.80) for Type A, Type B, and Type C. Intra-rater agreement: Nearly perfect agreement (κ = 0.83; 95% CI: 0.78-0.89) within raters for Type A, Type B, and Type C. Obeid's classification system: Inter-rater agreement: Almost perfect agreement (κ = 0.85; 95% CI: 0.83-0.87) for Type 0, Type 1, and Type 2. Complete system: Substantial agreement (κ = 0.68; 95% CI: 0.65-0.71) for all types and subtypes. Intra-rater agreement: Almost perfect at the type level (κ = 0.88; 95% CI: 0.83-0.93) and substantial at the subtype level (κ = 0.75; 95% CI: 0.65-0.85). The research findings indicate a high level of agreement between the classification system described by Qiu etal. and the classification system proposed by Obeid etal. This agreement supports the widespread adoption and utilization of these classification systems in future clinical studies.

A Biomechanical Analysis of Instrumentation Constructs During Vertebral Column Resection: Stability When You Need It!

Biomechanical Testing. Investigate the optimal construct for stabilization of the spine during vertebral column resection (VCR). VCR is a powerful technique for achieving correction in severe cases of spinal deformity. However, this also creates an unstable spine which requires stable fixation to prevent iatrogenic neurologic injury. It is common practice to place a temporary unilateral rod configuration to achieve this stability during surgery but no study to date has investigated the optimal construct configuration. A unilateral VCR model representing an acute 50° kyphotic deformity with a standardized 30mm resection was created. Three conditions underwent testing: 1) Rod material and diameter, 2) rod configuration, and 3) number of fixation points. Six unique samples were tested in each group in both flexion-extension. Prior to testing a 10N preload and underwent cyclical testing in flexion/extension. System stiffness was calculated and compared across groups. Assessment of rod size and composition using a single screw construct (2 total screws) demonstrated that for Titanium (Ti) rods, increasing rod size significantly increased the construct stiffness (P=0.001). Although Cobalt-chromium (Co-Cr) rods where significantly stiffer than the corresponding sized Ti rods, there was no significant difference between rod diameters for Co-Cr (P=0.98). However, when tested using a dual screw (4 total screws) construct, these constructs were significantly stiffer than the corresponding single screw constructs (P<0.0001). Of the various rod configurations, the dual rod demonstrated the greatest stiffness (34.8±2.1N/mm; P<0.0001). Surgical construct stiffness during a VCR is multifactorial. Larger rod diameter, increased number of fixation points, stiffer rod material, and increased number of rods across the resection site increase the construct stiffness. With minimal points of fixation using Co-Cr rods, increasing rod diameter does not impart greater construct stiffness unless additional fixation points are included.

Posterior Spinal Fusion for Severe Kyphosis in a Child with Gaucher Disease: A Case Report and Review of the Literature

Background: Skeleton involvement is one of the most significant aspects of Gaucher disease (GD). However, the treatment for spinal involvement in GD among patients undergoing enzyme replacement therapy (ERT) is poorly characterized. We present a case of progressive kyphotic spinal deformity in a young child caused by vertebral involvement, which was managed by posterior spinal fusion without anterior spinal release under ERT. Case presentation: This is a retrospective study. A 10-year-old boy presenting with progression kyphosis (thoracic kyphotic angle of 113°) associated with type-IIIb GD had undergone posterior spinal fusion with segmental pedicle screw fixation (from T6-L3) and Ponte osteotomy. The patient went back to school without further brace protection. Proximal junctional kyphosis (PJK) was observed at 4 months postoperatively. Revision surgery was performed to prevent neurological impairment. Additional posterior spinal fusion from T2–T6 and decompressive laminectomy were performed during the revision surgery. A 2-year follow-up showed no recurrence of PJK and solid fusion was achieved in the patient under ERT and brace protection. Conclusions: Posterior spinal fusion without anterior spinal release is a good treatment option for severe spinal deformity in patients with GD. However, the fusion level and reinforced fixation require careful consideration. Revision surgery and brace protection is needed as long as PJK is observed.

Contemporary utilization of three-column osteotomy techniques in a prospective complex spinal deformity multicenter database: implications on full-body alignment and perioperative course.

Research has focused on the increased correction from a three-column osteotomy (3CO) during adult spinal deformity (ASD) surgery. However, an in-depth analysis on the performance of a 3CO in a cohort of complex spinal deformity cases has not been described. This is a retrospective study on a prospectively enrolled, complex ASD database. This study aimed to determine if three-column osteotomies demonstrate superior benefit in correction of complex sagittal deformity at the cost of increased perioperative complications. Surgical complex adult spinal deformity patients were included and grouped into thoracolumbar 3COs compared to those who did not have a 3CO (No 3CO) (remaining cohort). Rigid deformity was defined as ΔLL less than 33% from standing to supine. Severe deformity was defined as global (SVA > 70mm) or C7-PL > 70mm, or lumbopelvic (PI-LL > 30°). Means comparison tests assessed correction by 3CO grade/location. Multivariate analysis controlling for baseline deformity evaluated outcomes up to six weeks compared to No 3CO. 648 patients were included (Mean age 61 ± 14.6years, BMI 27.55 ± 5.8kg/m2, levels fused: 12.6 ± 3.8). 126 underwent 3CO, a 20% higher usage than historical cohorts. 3COs were older, frail, and more likely to undergo revision (OR 5.2, 95% CI [2.6-10.6]; p < .001). 3COs were more likely to present with both severe global/lumbopelvic deformity (OR 4), 62.4% being rigid. 3COs had greater use of secondary rods (OR 4st) and incurred 4 times greater risk for: massive blood loss (> 3500mL), longer LOS, SICU admission, perioperative wound and spine-related complications, and neurologic complications when performed below L3. 3COs had similar HRQL benefit, but higher perioperative opioid use. Mean segmental correction increased by grade (G3-21; G4-24; G5-27) and was 4 × greater than low-grade osteotomies, especially below L3 (OR 12). 3COs achieved 2 × greater spinopelvic correction. Higher grades properly distributed lordosis 50% of the time except L5. Pelvic compensation and non-response were relieved more often with increasing grade, with greater correction in all lower extremity parameters (p < .01). Due to the increased rate of complications, 3COs trended toward higher perioperative cost ($42,806 vs. $40,046, p = .086). Three-column osteotomy usage in contemporary complex spinal deformities is generally limited to more disabled individuals undergoing the most severe sagittal and coronal realignment procedures. While there is an increased perioperative cost and prolongation of length of stay with usage, these techniques represent the most powerful realignment techniques available with a dramatic impact on normalization at operative levels and reciprocal changes.

Barriers to overlapping complex and general spine surgery at a tertiary academic hospital.

Policy concern and debate surround the concept of overlapping spine surgery. Overlapping surgery specifically refers to nonessential portions of the case or noncutting time overlap. This differs from concurrent surgery, in which critical portions of the procedure overlap. Here the authors explore the barriers for safe and efficient overlapping surgery in academic spinal deformity practice. Over a 24-month period, cases of spinal deformity, degenerative cases, anterior cervical discectomy and fusions (ACDFs), and laminectomy were reviewed for duration in operating room (OR) prior to surgery, duration of cutting time, duration in OR after surgery, turnover duration, and time delay from initial start time. Standard degenerative cases were referenced as 1-2 ACDFs as well as 1- to 2-level laminectomy surgery. The blocks of time between two consecutive cutting periods were investigated to determine the feasibility of overlapping an additional surgery. Specifically, the authors compared the blocks of time that include the postsurgery period, the turnover period, and the presurgery period to cutting periods. One hundred twenty-six complex spinal deformity procedures and 85 degenerative cases (including 49 ACDFs and 36 laminectomies) from one center and one neurosurgeon were reviewed. These procedures were performed between September 2019 and December 2021 with a 3-month gap in military deployment. On average, the procedure's duration for cases of deformity was 236.5 minutes, for cases of ACDFs it was 84 minutes, and for cases of laminectomies it was 105.5 minutes. The block of noncutting time while the patient was in the OR showed no difference from the surgical cut time. The turnover time between cases was 52.35 minutes. Of 100 cases scheduled as the first case of the day, 94 had a delay to the OR averaging 18.2 minutes. The data in this study indicate that estimates for pre- and postsurgical times alone are not sufficient to allow for overlapping surgery. The average cut-time duration of ACDF was 84 minutes; the average presurgical time for deformity was 68 minutes. This highlights the critical analysis for further examination of optimal scheduling, on-time first start, turnover periods, and the orchestration of all members of the providing team to optimize the cutting time for safe and consistent implementation of overlapping spine surgery.

Complications and outcomes after three-column osteotomy: a 5-year follow-up

Three-column spinal osteotomies (3-CO) are powerful techniques used to correct spinal deformity. These surgeries are associated with an elevated risk of complications. While outcomes have been reported in the literature with 2 years follow-up, longer-term outcomes of three-column osteotomies remain understudied. This study aims to examine patient reported outcomes and complications for three-column osteotomies at 5 years. Retrospective review of a prospectively collected spinal deformity cases database. All consecutive adult patients at a single spine surgery center treated with either a pedicle subtraction osteotomy (PSO) or vertebral column resection (VCR) for spinal deformity, and with a minimum 5-year follow-up were included. Visual-analog scale (VAS) for back pain score (0 to 10), Oswestry Disability Index (ODI) score (0 to 100), number of complications, revision rate, sagittal balance, lumbar lordosis at preoperative and at 5-year visit. Data was extracted from a prospectively collected spinal deformity surgery database continuously updated since 2002 with data from operative reports, patients' medical visit notes and patients' self-reported VAS and ODI questionnaires completed at each office visit. Radiographic measurements were performed on standing full-length spine radiographs taken at preop and 5-year visits. Descriptive statistics, comparison of means and proportions among groups, and a logistic regression analysis were conducted using the statistical software package SPSS version 28. Statistical significance was set at p<.05. Of 127 consecutive adult patients with minimum of 5-year follow-up undergoing a 3-CO posterior spinal surgery for spinal deformity were identified and included in the study, 79 (62%) were treated with PSO, and 48 (38%) with VCR. Both PSO and VCR groups demonstrated significant improvements in VAS (PSO preop: 6.7, 5-year: 4.6, p<.001; VCR preop: 7.1, 5-year: 5.2, p<.001), and ODI (PSO preop: 52.9, 5-year: 45.4, p<.001; VCR preop: 57.5, 5-year 43.0, p<.001) that were maintained at 5 years. Major and minor complications occurring within 5 years were not statistically different between the PSO and VCR groups (major: 59.5% vs 56.3%, p=.85; minor: 45.6% vs 37.5%, p=.46). The rate of revision surgery within 5 years was 39.4% overall. Of the fifty patients requiring revision, 37.5% were for nonunion, 27.1% instrumentation failure, 14.6% proximal junctional kyphosis (PJK), 12.5% vertebral fracture, 6.3% motor weakness, and 2.1% infection. Improvements in lumbar lordosis were maintained at 5 years in both the PSO (29.9° vs 47.2°, p<.001) and VCR (34.6° vs 48.5°, p<.001) groups while sagittal balance maintained significant improvement in the VCR group (9.5 cm vs 6.3 cm, p=.008) but not the PSO (11.4 cm vs 9.3 cm, p=.065). Patients undergoing three-column osteotomies had a major complication rate of 57.5% and a minor complication rate of 42.5% after 5 years. Improvements in lumbar lordosis were maintained at 5-year follow-up, but sagittal balance was only maintained in the VCR group. Despite these radiographic findings, both VCR and PSO groups maintained significant clinical improvements in both VAS and ODI scores at 5-year follow up.

Can Dynamic Spinal Stabilization Be an Alternative to Fusion Surgery in Adult Spinal Deformity Cases?

Rigid stabilization and fusion surgery are widely used for the correction of spinal sagittal and coronal imbalance (SCI). However, instrument failure, pseudoarthrosis, and adjacent segment disease are frequent complications of rigid stabilization and fusion surgery in elderly patients. In this study, we present the results of dynamic stabilization and 2-stage dynamic stabilization surgery for the treatment of spinal SCI. The advantages and disadvantages are discussed, especially as an alternative to fusion surgery. In our study, spinal, sagittal, and coronal deformities were corrected with dynamic stabilization performed in a single session in patients with good bone quality (without osteopenia and osteoporosis), while 2-stage surgery was performed in patients with poor bone quality (first stage: percutaneous placement of screws; second stage: placement of dynamic rods and correction of spinal SCI 4-6 months after the first stage). One-stage dynamic spinal instrumentation was applied to 20 of 25 patients with spinal SCI, and 2-stage dynamic spinal instrumentation was applied to the remaining 5 patients. Spinal SCI was corrected with these stabilization systems. At 2-year follow-up, no significant loss was observed in the instrumentation system, while no significant loss of correction was observed in sagittal and coronal deformities. In adult patients with spinal SCI, single or 2-stage dynamic stabilization is a viable alternative to fusion surgery due to the very low rate of instrument failure. This study questions the use of dynamic stabilization systems for the treatment of adult degenerative deformities.

Scoliosis and kyphosis in blue-spotted and marbled flathead fish associated with a Myxobolus acanthogobii-like parasite.

Spinal deformities in finfish have the potential to impact aquaculture industries and wild populations by increasing morbidity, mortality, and reducing growth rates. Myxobolus acanthogobii has been implicated in causing scoliosis and lordosis in various aquatic species in Japan. We investigated 4 cases of spinal deformity in 2 flathead (Platycephalus) species that were submitted to the Elizabeth Macarthur Agricultural Institute (EMAI) in New South Wales (NSW), Australia, between 2015 and 2021. Flathead are commercially significant species that are popular among Australian consumers, and are also sought-after species targeted by recreational fishers. Gross deformities are concerning to the community and may impact the quality and quantity of specimens available for consumption. Three blue-spotted flathead (P. caeruleopunctatus) and one marbled flathead (P. marmoratus) were submitted, all with marked scoliosis and kyphosis; 1-2-mm cysts were present on the dorsum of the brain, most often over the optic lobe or cerebellum. Cytology and differential interference microscopy of cyst material revealed numerous oval spores, x̄ 14 ± SD 0.75 µm × x̄ 11.5 ± SD 0.70 µm, with 2 pyriform polar capsules, the morphology of which is consistent with a Myxobolus sp. PCR assay and 18S rDNA sequencing of the cyst material identified a Myxobolus sp. with 96% identity to M. acanthogobii. The identification of this Myxobolus sp. confirms the presence of parasites with the potential to cause spinal deformity in significant aquatic species in NSW waterways.

Clinical and Radiologic Analysis of Minimally Invasive Anterior-Posterior Combined Surgery for Adult Spinal Deformity: Comparison of Oblique Lateral Interbody Fusion at L5/S1 (OLIF51) versus Transforaminal Interbody Fusion.

Background and Objectives: Although adult spinal deformity (ASD) surgery brought about improvement in the quality of life of patients, it is accompanied by high invasiveness and several complications. Specifically, mechanical complications of rod fracture, instrumentation failures, and pseudarthrosis are still unsolved issues. To better improve these problems, oblique lateral interbody fusion at L5/S1 (OLIF51) was introduced in 2015 at my institution. The objective of this study was to compare the clinical and radiologic outcomes of anterior-posterior combined surgery for ASD between the use of OLIF51 and transforaminal interbody fusion (TLIF) at L5/S1. Materials and Methods: A total of 117 ASD patients received anterior-posterior correction surgeries either with the use of OLIF51 (35 patients) or L5/S1 TLIF (82 patients). In both groups, L1-5 OLIF and minimally invasive posterior procedures of hybrid or circumferential MIS were employed. The sagittal and coronal spinal alignment and spino-pelvic parameters were recorded preoperatively and at follow-up. The quality-of-life parameters and visual analogue scale were evaluated, as well as surgical complications at follow-up. Results: The average follow-up period was thirty months (13-84). The number of average fused segments was eight (4-12). The operation time and estimated blood loss were significantly lower in OLIF51 than in TLIF. The PI-LL mismatch, LLL, L5/S1 segmental lordosis, and L5 coronal tilt were significantly better in OLIF51 than TLIF. The complication rate was statistically equivalent between the two groups. Conclusions: The introduction of OLIF51 for adult spine deformity surgery led to a decrease in operation time and estimated blood loss, as well as improvement in sagittal and coronal correction compared to TLIF. The circumferential MIS correction and fusion with OLIF51 serve as an effective surgical modality which can be applied to many cases of adult spinal deformity.

"Critical pedicle wall" breaches analysis in complex spinal deformity using O-arm navigation.

Free-hand and fluoroscopic-guided pedicle screw placement has been associated with higher rates of pedicle breaches (frequency range 15-40% especially in deformed pedicles). Neurological complications are more "critical" (i.e., frequent and significant) with medial and inferior pedicle-wall breaches due to the proximity of the neural elements. Here, we analyzed the effectiveness of O-arm navigation in minimizing "critical" pedicle wall breaches and their complications in 21 complex spinal deformity cases. Twenty-one complex spinal deformity cases were prospectively managed with O-arm-navigated posterior-instrumented fusions. Preoperative assessment included; evaluation of the type of scoliosis, the magnitude of the deformity, and the anatomy of the pedicles - (i.e., classified using Watanabe et al.). The O-arm was used to confirm and grade both the intraoperative and postoperative location of screws. Other variables analyzed included; duration of surgery, estimated blood loss, complications, and radiation exposure. In 21 patients, 259 (63.45%) of 384 pedicles were instrumented; we observed 22 of 259 pedicle screw breaches. Significant (>2 mm) breaches were observed in two medial and one inferior wall cases that required revision; the overall biomechanically significant screw breach rate was (3/259) 1.2% with an accuracy rate of 98.8%. Pedicle screw placement resulted in another 14 nonsignificant (<2 mm) breaches; ten were medial and four involved the inferior wall. As anterior, lateral, and "in-out-in" trajectory pedicle screws beaches were nonsignificant, they were not included in our analysis. O-arm navigation decreased the incidence of medial and inferior (i.e., >2 mm "critical") pedicle screw breaches applied in 21 patients with deformed pedicles due to scoliosis. Further, the O-arm minimized the operating time, decreased the estimated blood loss, and reduced the incidence of complications.

The adjunct use of descending neurogenic-evoked potentials when transcranial motor-evoked potentials degrade into warning criteria in pediatric spinal deformity surgery: minimizing false-positive events.

This studies objective was to evaluate the utility of descending neurogenic-evoked potentials (DNEPs) in the setting of transcranial motor-evoked potentials (TCeMEPs) degradation into warning criteria during pediatric spinal deformity surgery. An institutional spinal cord monitoring database was queried to identify all primary and revision pediatric spinal deformity cases, < / = 21years of age performed from 1/2006 to 12/2021, in which TCeMEPs were the primary motor tract assessment modality which degraded into warning criteria, with subsequent initiation of adjunct DNEPs. Fourteen surgical cases (0.42%; 3351 total cases) in fourteen patients met inclusion criteria. Mean age was 13.2years (7.5-21.3). syndromic (n = 7), kyphosis (n = 3), congenital (n = 2), and idiopathic (n = 2). Three-column osteotomies (3CO)were done in eight patients. TCeMEPs degraded into warning criteria during screw placement (n = 7), 3CO performance/closure (n = 4), or deformity correction (n = 3). DNEPs were present in all cases of warning-criteria TCeMEPs and one case had degradation of DNEPs. Intraoperative Stagnara wake-up tests were performed in only 2/14 cases, with one transient new neurologic deficit (NND). In this specific scenario, DNEPs sensitivity was 50%, specificity 100%, positive predictive value 100%, and negative predictive value 92% to detect aNND. DNEPs were useful in assessing spinal cord function in the setting of TCeMEP data degradation in complex pediatric deformity surgeries. DNEPs demonstrated a higher specificity and positive predictive value in this clinical setting than TCeMEPs when assessing long-term neurologic function after surgery. Based on this small cohort, DNEPs appear to be a useful adjunct modality to TCeMEPs, in this challenging clinical scenario.

SHORT- TO MIDTERM RADIOGRAPHIC AND CLINICAL OUTCOMES OF ANTERIOR OPENING OSTEOTOMY WITH LAMINA SPARING IN POST-TRAUMATIC KYPHOSIS: A CASE SERIES

Purpose: Most spinal osteotomy procedures applied for spinal deformity and concomitant malalignment cases are associated with varied complications. This study evaluates the short- to midterm clinical and radiographic efficacy of the transpedicular anterior opening osteotomy technique. Methods: We retrospectively enrolled six patients who underwent transpedicular anterior opening osteotomy due to symptomatic rigid kyphotic deformity from May 2005 to 2016. During surgery, we created a new fracture line at the collapsed anterior vertebral body through bilateral pedicles, filled spaces with compacted bone grafts while preserving posterior elements, including lamina, and secured structure using posterior instrumentation. The kyphotic Cobb angle, Visual Analog Scale (VAS), and Oswestry Disability Index (ODI) before and after surgery were measured and analyzed. Results: The mean preoperative kyphotic Cobb angle was 31.41 ± 4.77[Formula: see text] while the postoperative value was 15.75 ± 1.66[Formula: see text]. The mean correction angle was 15.55 ± 6.66[Formula: see text]. The mean follow-up duration was 50.17 ± 44.16 months. During the final follow-up, the mean kyphotic angle was not statistically different from the postoperative values. All patients with documented VAS Back and ODI had improved values postoperatively. Conclusions: Transpedicular anterior opening osteotomy with posterior element preservation improves clinical outcomes and is safe and effective in correcting regional, fixed kyphotic deformities.

Robotics is useful for less-experienced surgeons in spinal deformity surgery.

To verify whether robotics was useful for surgeons who had less experience with spinal deformity surgery. A retrospective review was conducted of 70 consecutive patients who underwent robotic-assisted pedicle screw placements with open procedures using a spine robotic system (Mazor X Stealth Edition) at a single institution from April 2021 to April 2022. Gertzbein-Robbins grades were used to assess the deviation of the 599 pedicle screws in the postoperative CT images. The rate of Grade A was considered the perfect accuracy rate, and the rate of Grades C, D, and E was calculated as the deviation rate. The perfect accuracy rate and deviation rate were compared between the spinal deformity and the non-deformity groups. The perfect accuracy rate, deviation rate, and screw insertion time were compared in the spinal deformity cases between the expert surgeon group and the less-experienced surgeon group. The deviation rate of the spinal deformity group was higher than that of the non-deformity group even though there was no statistically significant difference (spinal deformity group: 2.3%, non-deformity group: 1.2%, p = 0.350). In the spinal deformity cases, there was no significant difference in the perfect accuracy rate between the expert surgeon group and the less-experienced surgeon group, but the deviation rate was significantly lower in the less-experienced surgeon group (expert surgeon group: 5.0%, less-experienced surgeon group: 0%, p = 0.008). The screw insertion time was significantly shorter in the less-experienced surgeon group. Robotics is particularly useful for surgeons with less experience in spinal deformity surgery.

Fusion Mass Screws in Revision Spinal Deformity Surgery: A Simple and Safe Alternative Fixation.

Revision spinal deformity surgery has a high rate of complications. Fixation may be challenging due to altered anatomy. Screws through a fusion mass are an alternative to pedicle screw fixation. The purpose of this retrospective study was to further elucidate the safety and efficacy of fusion mass screws (FMSs) in revision spinal deformity surgery. Retrospective case series. Fifteen freehand FMSs were placed in 6 patients with adult spinal deformity between 2016 and 2018 by the senior author. FMSs were combined with pedicle screws, at times at the same level. FMSs were used to save distal levels from fusion, assist in closing a 3-column osteotomy and provide additional fixation in cases of severe instability. Computed tomography (CT) was used to assess bone mineral density (BMD) and thickness of each fusion mass preoperatively along with accuracy of FMS placement postoperatively. The mean BMD of the fusion mass was 397 Hounsfield units (HU; range: 156-628 HU). The mean AP thickness of the fusion mass was 15.5 ± 4.8 mm (range: 8.6-24.4 mm). The mean FMS length was 35.3 ± 5.5 mm (range: 25-40 mm). There was no evidence of FMS loosening, breakage, or pseudarthrosis at latest follow-up (mean: 2.2 years, range: 1.4-3.1 years). No neurologic deficits were observed. 1/15 screws had a low-grade breach into the canal (<2 mm). No patients required revision surgery. FMSs may be used to augment fixation in revision spinal deformity cases when pedicle screw placement may be challenging. FMSs may also provide an additional anchor at levels with pedicular fixation.

Simulation Training in Pedicle Preparation and Screw Insertion in Pediatric Spinal Deformity

Pedicle screw segmental instrumentation has become the gold standard for spinal deformity correction for both the pediatric and adult populations. The thought of placing screws through tiny boney channels in the spinal column can be a daunting task for trainees. The goal in spine surgery instrumentation is similar to other orthopaedic subspecialities—safe passage of screws through the bone. Yet, the potential consequences of pedicle breaches and malpositioned instruments/screws are what give pedicle preparation and screw insertion an appropriately heightened sense of care and apprehension. Important anatomical structures lie around the pedicles of the spine, with the spinal cord, nerve roots, epidural veins, lungs, kidneys, and major vessels being just some of the structures that lurk outside of the spine’s osseous anatomy. In 2007, we implemented power pedicle screw preparation and screw insertion to improve safety for both the surgeon and patient. A recent multicenter study of early adopters demonstrated the safety of this technique in 22,209 screws across six institutions. As we have taught this technique to fellow surgeons throughout the world, inevitably the question would always arise, “Do you let your residents do that?”. The answer was always an emphatic, YES. However, we began to explore ways in which we could improve our trainees’ education on pedicle screw insertion, both manual and power, given the complexity of the osseous anatomy in pediatric spinal deformity cases.

Trends in Intraoperative Assessment of Spinal Alignment: A Survey of Spine Surgeons in the United States.

Study Design:Survey.Objectives:To characterize national practices of and shortcomings surrounding intraoperative assessments of spinal alignment.Methods:Spine surgeons in the US were surveyed to analyze their experience with assessing spinal alignment intraoperatively.Results:108 US spine surgeons from 77 surgical centers with an average of 19.2 + 8.8 years of surgical experience completed the survey. To assess alignment intraoperatively, 84% (91/108) use C-arm or spot radiographs, 40% (43/108) use full-length radiographs, and 20% utilize the T-bar (22/108). 88% of respondents’ surgical centers (93/106) possessed a navigation camera and 63% of respondents (68/108) report using surgical navigation for 40% of their deformity cases on average. Reported deterrents for using current technology to assess alignment were workflow interruption (54%, 58/108), expense (33%, 36/108), and added radiation exposure (26%, 28/108). 87% of respondents (82/94) reported a need for improvement in current capabilities of making intraoperative assessments of spinal alignment.Conclusions:Corrective surgery for spinal deformity is a complex procedure that requires a high level of expertise to perform safely. The majority of surveyed surgeons primarily rely on radiographs for intraoperative assessments of alignment. Despite the majority of surveyed surgical practices possessing navigation cameras, they are utilized only for a minority of spinal deformity cases. With the majority of surveyed surgeons reporting a need for improvement in technology to assess spinal alignment intraoperatively, 3 of the top design considerations should include workflow interruption, expense, and radiation exposure.

Single-Surgeon Versus Dual-Surgeon Strategy in Spinal Tumor Surgery: A Single Institution Experience.

Retrospective cohort study. The objective of this study is to compare the outcomes of spinal tumor surgery between dual-surgeon and single-surgeon approach. Perioperative adverse outcomes may be improved with 2 attending surgeons in spinal deformity cases. It is unclear if this advantage may be seen in spinal oncology operations. A retrospective chart review identified 24 patients who underwent spinal tumor surgery by two attending surgeons between January 1, 2016, and April 30, 2020 at a single tertiary care institution. 1:1 matching was then performed to identify 24 patients who underwent spinal tumor operations of similar complexity by a single attending surgeon. Postoperative outcomes were collected. Cases in the dual-surgeon group had significantly lower total operative time (601 vs. 683 minutes), reduced estimated blood loss (956 vs. 1780 ml), and were less likely to have an intraoperative blood transfusion (41.7% vs. 75.0%). The incidence of cerebrospinal fluid leak and wound infection did not significantly differ between groups, nor were there differences in total length of hospital stay, discharge disposition, 6-month emergency room visit, readmission, and reoperation rates. Dual-surgeon strategy in spinal tumors surgery may lead to decreased operative time and estimated blood loss. These benefits may have clinical and cost implications, but should be weighed against the impact of resident and fellow training. Level III.

Impact of an intraoperative coronal spinal alignment measurement technique using a navigational tool for a 3D spinal rod bending system in adult spinal deformity cases.

In corrective spinal surgery for adult spinal deformity (ASD), the focus has been on achieving optimal spinopelvic alignment. However, the correction of coronal spinal alignment is equally important. The conventional intraoperative measurement methods currently used for coronal alignment are not ideal. Here, the authors have developed a new intraoperative coronal alignment measurement technique using a navigational tool for a 3D spinal rod bending system (CAMNBS). The purpose of this study was to test the feasibility of using the CAMNBS for coronal spinal alignment and to evaluate its usefulness in corrective spinal surgery for ASD. In this retrospective cohort study, patients with degenerative lumbar kyphoscoliosis, a Cobb angle ≥ 20°, and lumbar lordosis ≤ 20° who had undergone corrective surgery (n = 67) were included. The pelvic teardrops on both sides, the S1 spinous process, the central point of the apex, a point on the 30-mm cranial (or caudal) side of the apex, and the central point of the upper instrumented vertebra (UIV) and C7 vertebra were registered using the CAMNBS. The positional information of all registered points was displayed as 2D figures on a monitor. Deviation of the UIV plumb line from the central sacral vertical line (UIV-CSVL) and deviation of the C7 plumb line from the CSVL (C7-CSVL) were measured using the 2D figures. Nineteen patients evaluated using the CAMNBS (BS group) were compared with 48 patients evaluated using conventional intraoperative radiography (XR group). The UIV-CSVL measured intraoperatively using the CAMNBS was compared with that measured using postoperative radiography. The prevalence of postoperative coronal malalignment (CM) and the absolute value of postoperative C7-CSVL were compared between the groups on radiographs obtained in the standing position within 4 weeks after surgery. Postoperative CM was defined as the absolute value of C7-CSVL ≥ 30 mm. Further, the measurement time and amount of radiation exposure were measured. No significant differences in demographic, sagittal, and coronal parameters were observed between the two groups. UIV-CSVL was 2.3 ± 9.5 mm with the CAMNBS and 1.8 ± 16.6 mm with the radiographs, showing no significant difference between the two methods (p = 0.92). The prevalence of CM was 2/19 (10.5%) in the BS group and 18/48 (37.5%) in the XR group, and absolute values of C7-CSVL were 15.2 ± 13.1 mm in the BS group and 25.0 ± 18.0 mm in the XR group, showing statistically significant differences in both comparisons (p = 0.04 and 0.03, respectively). The CAMNBS method required 3.5 ± 0.9 minutes, while the conventional radiograph method required 13.3 ± 1.5 minutes; radiation exposure was 2.1 ± 1.1 mGy in the BS group and 2.9 ± 0.6 mGy in the XR group. Statistically significant differences were demonstrated in both comparisons (p = 0.0002 and 0.03, respectively). From this study, it was evident that the CAMNBS did not increase postoperative CM compared with that seen using the conventional radiographic method, and hence can be used in clinical practice.

Pelvic incidence is a risk factor for lower instrumented vertebra failure in adult spinal deformity patients who underwent corrective fusion terminating at the L5 vertebra

Factors related to postoperative mechanical failure after long fusion with lower instrumented vertebra (LIV) at L5 have not been well investigated. Elucidating such factors may allow us to perform alternatives to spinopelvic fusion for adult spinal deformity (ASD) cases. We investigated the incidence and risk factors of LIV failure in patients with ASD who underwent surgical treatment of long corrective fusion until the L5 vertebrae. Between 2009 and 2018, 52 patients who underwent corrective fusions to L5 were followed-up for at least one-year. We evaluated the associated patient factors for LIV failure which include loosening of the pedicle screw of LIV, fracture of LIV, distal junctional kyphosis (DJK). The mean age of the participants was 71.2±7.59 (range, 44-84). LIV failure occurred in 20 patients (38.5%), and 6 patients (11.5%) underwent secondary surgery for caudal segments. The mean pelvic incidence (PI) was 52.5±9.8 in the failure group versus 45.3±11.4 in non-failure group (P=0.02) and pelvic tilt (PT) was 39.1±9.0 versus 32.4±13.0. There were no significant differences in sex, age, body mass index, number of levels fused, and other radiographic data. Logistic regression analysis that included T1 pelvic angle, PT, PI - postoperative LL and PI also identified PI as the only significant determinant of LIV failure (OR=1.07, P=0.034). Receiver operating characteristic analysis demonstrated that a PI over 50.0° was associated with LIV failure (sensitivity 63%, specificity 70%, AUC 0.694). LIV failure was frequently observed after long corrective fusion for patients with ASD. High PI was found to be a significant risk factor for the LIV failure.

Development and initial validation of classification for severe spinal deformity based on X-ray features.

To develop a clinically feasible classification for severe spinal deformity based on X-ray features. A total of 223 consecutive severe spinal deformity cases who underwent corrective operation were enrolled from 2004 to 2015 retrospectively. Based on X-ray features, a novel classification was developed containing three components: curve types, curve angle and apex location. There were five curve types as follows: single scoliosis (SS), kyphoscoliosis (KS), angular deformity (AD), long curve (LC), and double curves (DC). Curve angle subsection on coronal and sagittal planes including A:90-109, B:110-129, C:130-149, D: > 150. Apex location means the exact level of apex located. Reliability of the classification was tested. The kappa values for inter-observer and intra-observer reliability of the curve types, curve angle, and apex level were larger than 0.80. X-ray classification for overall patients with severe spinal deformity showed that there were 101 SS cases, 47 KS, 46 AD, 19 LC and 10 DC. For the curve angle, there were grade A 123 cases, B 43, C 18, D 15 on coronal plane and grade A 38, B 17, C 16, and D 19 on sagittal plane. Apex location showed there were 27 patients at T7 or upper levels, 31 on T8, 58 on T9, 45 on T10, 18 on T11, and 44 at T12 or lower levels. A novel classification for severe spinal deformity was described based on X-ray morphology. A high value for inter-observer and intra-observer reliability was shown. Each subgroup has its particular influence on decision-making and prognostic prediction.