Spinal Deformity Correction Surgery Research Articles

Impact of Knee Osteoarthritis and Arthroplasty on Full Body Sagittal Alignment in Adult Spinal Deformity Patients.

Retrospective analysis of prospectively collected data. This study evaluates the impact of knee osteoarthritis (OA) and knee arthroplasty on alignments and patient-reported outcomes measures (PROMS) of patients undergoing adult spinal deformity (ASD) corrective surgery. The relationship between knee OA and spinal alignment in patients with ASD is incompletely understood. It is also unknown how patients with knee arthroplasty and ASD compare to ASD patients with native knees. Baseline full-body radiographs were used, and hip and knee OA were graded by two independent reviewers using the KL classification. Spinopelvic parameters and PROMs were compared across the different knee OA groups and compared between patients with knee replacement and native knees. 199 patients with bilateral non severe OA (G1), 31 patients with unilateral severe knee OA (G2), and 60 patients with bilateral severe knee OA (G3). Patients with severe knee OA presented with worse spinopelvic parameters. However, after multivariable regression analysis controlling for age, frailty, PI, T1PA, knee OA was an independent predictor of knee flexion (G1:-0.02±7.3, G2: 7.8±9.4, G3: 4.5±8.7, P<0.001), and ankle dorsiflexion (G1: 2.3±4.0, G2: 6.6±4.5, G3: 5.1±4.1, P<0.001). There was no difference in PROMs (P>0.05). Secondary analysis included 96 patients: 48 patients (50%) with non-severe knee OA, and 48 patients (50%) with knee replacement. There was no difference in radiographic parameters or PROMs between the groups. In this study of complex ASD patients, patients with worse spinal deformity were more likely to have concomitant knee OA. Knee OA was shown to be a predictor of knee flexion and ankle dorsiflexion angles, but was not associated with worse PROMs in this study population. Patients with knee arthroplasty, however, had comparable spinal alignment and PROMs relative to those with mild OA.

Which components of the global alignment proportionality score have the greatest impact on outcomes in adult spinal deformity corrective surgery?

To investigate the impact of the Global Alignment and Proportion (GAP) score components on patient outcomes in Adult Spine Deformity (ASD) surgery. Patients included underwent assessment via the GAP score and its individual components: pelvic version (GAP PV), lumbar lordosis (GAP LL), lumbar distribution index (GAP LDI) and spinopelvic component (GAP SP). Multivariable analyses assessed the association between alignment in these components and clinical outcomes in ASD patients. 762 ASD patients met inclusion criteria. Alignment in GAP SP independently predicted meeting MCID for SR-22S and ODI and was associated with a lower likelihood of developing mechanical complications. Patients aligned in GAP SP were less likely to develop proximal junctional kyphosis (OR 0.42, 0.26-0.73, p = 0.01) and PJF (OR 0.3, 0.13-0.74, p = 0.01). Proportioned alignment in GAP SP with disproportioned alignment in GAP LDI contributed to an increased risk of PJK and PJF (OR 2.67, 95% CI 1.95-6.82, p = 0.045). There was no significant association of GAP SP proportionality and GAP RPV (OR 1.1, 0.86-2.15, p = 0.253) or GAP LL (OR 1.34, 0.78-4.23, p = 0.673) disproportionality with outcomes. Disproportioned alignment in GAP SP but proportioned alignment in both GAP LL and GAP LDI was associated with decreased likelihood of PJK (OR 0.53, 95% CI 0.39-0.94, p = 0.02) and PJF (OR 0.31, 95% CI 0.19-0.67, p = 0.001). The spinopelvic component of the GAP score is the most significant independent predictor of clinical outcomes. Its interaction with the other components of the GAP score also aids assessment of the risk for mechanical complications.

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

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. 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. 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%. 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.

Do Obese Patients Have Worse Outcomes in Adult Spinal Deformity Surgeries?: A Meta-analysis.

A meta-analysis study. This meta-analysis evaluates the difference in surgical outcomes between obese and nonobese patients undergoing adult spinal deformity (ASD) corrective surgery. ASD encompasses a wide range of debilitating spinal abnormalities. Concurrently, obesity is on the rise globally and has been shown to influence the outcomes of ASD management. The relationship between obesity and surgical outcomes in ASD has been the focus of recent studies, yielding various results. We conducted a comprehensive search of PubMed, Cochrane, and Google Scholar (pages 1-20) through June of 2024. The surgical outcomes assessed included postoperative complications, revision rates, wound infections, thromboembolic events, implant-related complications, and nonhome discharge. Surgical parameters such as operative time, length of stay (LOS), and estimated blood loss (EBL), as well as functional outcomes like the Oswestry Disability Index (ODI) and pain scores were analyzed. Nine studies met the inclusion criteria. Nonobese patients exhibited a lower rate of implant-related complications [odds ratio (OR)=0.25; 95% CI: 0.12-0.52, P =0.0002] and nonhome discharge (OR=0.52; 95% CI: 0.32-0.84, P =0.007). In addition, nonobese patients had reduced LOS (MD=-0.29; 95% CI: -0.53 to -0.05, P =0.02) and EBL (SMD=-0.68; 95% CI: -1.19 to -0.18, P =0.008). No statistically significant differences were observed for the remaining outcomes. Nonobese patients undergoing ASD corrective surgery are associated with fewer implant-related complications, a lower EBL, shorter LOS, and a higher likelihood of being discharged home compared with their obese counterparts.

Machine learning applications in adult spinal deformity corrective surgery: a narrative review

Machine learning applications in adult spinal deformity corrective surgery: a narrative review

Machine Learning Applications in Adult Spinal Deformity Corrective Surgery: A Narrative Review

Machine Learning Applications in Adult Spinal Deformity Corrective Surgery: A Narrative Review

P132. Alignment schematic impact on complications and outcomes in adult spinal deformity corrective surgery

P132. Alignment schematic impact on complications and outcomes in adult spinal deformity corrective surgery

P176. Waiting on a response: a full-body analysis of patients maintaining pelvic compensation following adult spinal deformity corrective surgery

P176. Waiting on a response: a full-body analysis of patients maintaining pelvic compensation following adult spinal deformity corrective surgery

P149. Optimal octogenarians: which elderly patients best tolerate adult spinal deformity corrective surgery?

P149. Optimal octogenarians: which elderly patients best tolerate adult spinal deformity corrective surgery?

Perioperative Benefits of a 3D Printed Spine Biomodel in the Setting of Congenital Scoliosis Surgery

The spine community is continuously adding to its armamentarium of intraoperative techniques for visualization and instrumentation of the spine. Recently, three-dimensional printed spine models were introduced for use in preoperative planning, surgical simulation, and intraoperative guidance. We present a 14-year old African male with congenital kyphoscoliosis, small stature, an obvious gibbus deformity and coronal imbalance, who underwent a three-staged posterior surgical correction procedure, during which a 3D-printed spine biomodel was utilized for better appreciation of his complex spinal deformity patho-anatomy. During the first stage of the procedure, he developed diminished lower extremity motor strength bilaterally and bowel/bladder control, but, following his third stage procedure and with focused rehabilitation efforts, he has regained full control of his bowel and bladder function, and is able to ambulate and perform activities of daily living independently, albeit still requiring intermittent walking support with a single forearm crutch due to residual left leg weakness. The 3D spine biomodel functioned successfully as a valuable tool and surrogate anatomic blueprint for the surgeons, enabling adequate appreciation of the complex bony anatomy which could not be easily resolved on the conventionally available imaging modalities, intraoperative navigation or robotic platform. Theoretically, up to $2900 USD in savings, translated from the mean estimated time saved per procedure with the use 3D-printed spine models has been proposed in some studies. Therefore, 3D-printed spine models have utility in complex spinal deformity correction surgery.

Durability of substantial clinical benefit leading to optimal outcomes in adult spinal deformity corrective surgery: a minimum 5-year analysis.

The objective was to evaluate factors associated with the long-term durability of outcomes in adult spinal deformity (ASD) patients. Operative ASD patients fused from at least L1 to the sacrum with baseline (BL) to 5-year (5Y) follow-up were included. Substantial clinical benefit (SCB) in Oswestry Disability Index (ODI), numeric rating scale (NRS)-back, NRS-leg, and Scoliosis Research Society (SRS)-22r scores and physical component score were assessed on the basis of previously published values. Factors were evaluated on the basis of meeting optimal outcomes (OO) at 2 years (2+) and 5 years (5+). Furthermore, 2+ patients were isolated and evaluated on the basis of meeting OO at 5 years (2+5+) or not at 5 years (2+5-). OO were defined as follows: no reoperation, major mechanical failure, proximal junctional failure, and meeting either 1) SCB in terms of ODI score (decrease > 18.8) or 2) ODI < 15 and SRS-22r total > 4.5. In total, 330 ASD patients met the inclusion criteria, with 45.5% meeting SCB for ODI at 2 years, while 46.0% met SCB at 5 years; 79% of those who achieved 2-year (2Y) SCB went on to achieve 5Y SCB. This rate was lower for OO, with 41% achieving 2Y OO (2+), while 37% met 5Y OO (5+) and 80% of 2+ patients had durable outcomes until 5+ (32% of the total cohort). Of the patient factors, frailty was significantly different among groups at 2 years, while comorbidity burden was significantly different at 5 years and the combination thereof differed in those with durable outcomes. Those who regained their level of activity postoperatively had 4 times higher odds of maintaining OO from 2 years to 5 years (p < 0.05). Osteoporosis rates, although equivocal at BL, were higher at the last follow-up in those who met 2Y OO but failed to meet 5Y OO. The odds of achieving OO at 5 years in 2+ patients decreased by 47% for each additional comorbidity and decreased by 74% in those who had lower-extremity paresthesias at BL (both p < 0.05). Controlling for patient factors and BL disability found fewer levels fused, decreased correction of sagittal vertical axis, and increased correction of pelvic incidence-lumbar lordosis mismatch to be predictive of maintaining 2Y OO until 5 years (p < 0.05). SCB was met in 46% of ASD patients at 5 years. The durability of OO was seen in a third of patients until 5 years postoperatively. Higher rates of medical complications were seen in those who failed to achieve and maintain OO until 5 years. Frailty and comorbidity burden were significant factors associated with the achievement and durability of OO until 5 years.

Should the pelvis be included? An analysis of distal junctional failure risk factors in correcting adult spinal deformity in women with fusion to L5.

To identify the risk factors for distal junctional failure (DJF) in women treated for adult spine deformity with fusion to L5 and to highlight the significance of preoperative assessment, surgical decision-making, and postoperative care. This is a retrospective study of data collected prospectively on the local institutional spine surgery registry (2016-2021). All patients, women older than 18 years, with a diagnosis of adult spine deformity who underwent long posterior instrumentation to L5 and had a minimum of 2-years follow-up were included in the study (two groups: with or without DJF). Demographic and radiographic data, corrective strategy, preoperative level of degeneration at L5/S1 and GAP score were compared between the two groups. Forty-eight patients (n = 48) satisfied eligibility criteria. At two-years follow-up, nine patients (18,7%) developed a DJF that required surgical revision. Thirty-nine patients did not present distal junctional complications. Patients with or without DJF showed significant differences in terms of preoperative spinopelvic parameters (PT: 28°± 6° vs. 23°± 9°, p-value 0.05; DJF group vs. not DJF) and degeneration of L5-S1 (Pfirmann grade L5-S1 disc 3.7 ± 1.0 vs. 2.6 ± 0.8, p-value 0.001; DJF group vs. not DJF) (L5-S1 Facet joint Osteoarthritis 3.1 ± 0.8 vs.2.4 ± 0.8, p-value 0.023; DJF group vs. not DJF). DJF following spinal deformity correction surgery is influenced by a combination of patient-related, surgical and implant-related factors. Fusion construct length, preoperative and postoperative sagittal alignment and the grade of degeneration of the distal disc have been identified as significant risk factors. Surgeons should carefully evaluate these factors and employ appropriate strategies.

Impact of Spinal Surgery on Intrathecal Nusinersen Injections in Pediatric Spinal Muscular Atrophy.

Complex spinal deformities necessitate surgical interventions that may intervene with intrathecal injections in patients with spinal muscular atrophy (SMA). This study aimed to determine the effect of spinal deformity correction surgery on nusinersen administration. Pediatric patients with SMA, operated by a single surgeon, either via magnetically controlled growing rod (MCGR) or definitive fusion (DF) with skip instrumentation, were evaluated retrospectively in terms of safety and feasibility of intrathecal injections. Patients' and their parents' perspectives were evaluated through a questionnaire regarding any shift in the setting of injections. Fourteen patients with 15 spinal surgeries (10 MCGR and 5 DF) were included. Eleven patients received intrathecal treatment both before and after the surgery. Preoperative (n=3) and postoperative (n=9) fluoroscopic guidance was required leading to a shift in the application settings in 6 patients. Of 106 preoperative injections, 15% required fluoroscopy and 2% required anesthesia. Postoperatively, of 88 injections, 73% required fluoroscopy and 26% required anesthesia. No patients discontinued intrathecal injections due to technical difficulties associated with the spinal surgery. This study demonstrates that spinal surgery does not prevent safe and successful intrathecal nusinersen injections. In the DF group, the skip instrumentation technique provided access to interlaminal space for intrathecal injections. In either surgical group, no further auxillary approach was required. Modifications in the injection technique require an institutional approach, and concerns of patients and their families should be addressed accordingly. IV.

Development of Consensus-Based Best Practice Guidelines for the Perioperative and Postoperative Care of Pediatric Patients With Spinal Deformity and Programmable Implanted Devices.

Modified Delphi consensus study. To develop consensus-based best practices for the care of pediatric patients who have implanted programmable devices (IPDs) and require spinal deformity surgery. Implanted programmable devices (IPDs) are often present in patients with neuromuscular or syndromic scoliosis who require spine surgery. Guidelines for monitoring and interrogating these devices during the perioperative period are not available. A panel was assembled consisting of 25 experts (i.e., spinal deformity surgeons, neurosurgeons, neuroelectrophysiologists, cardiologists, and otolaryngologists). Initial postulates were based on a literature review and results from a prior survey. Postulates addressed the following IPDs: vagal nerve stimulators (VNS), programmable ventriculoperitoneal shunts (VPS), intrathecal baclofen pumps (ITBP), cardiac pacemakers and implantable cardioverter-defibrillators (ICD), deep brain stimulators (DBS), and cochlear implants. Cardiologist and otolaryngologist participants responded only to postulates on cardiac pacemakers or cochlear implants, respectively. Consensus was defined as ≥80% agreement, items that did not reach consensus were revised and included in subsequent rounds. A total of 3 survey rounds and 1 virtual meeting were conducted. Consensus was reached on 39 total postulates across 6 IPD types. Postulates addressed general spine surgery considerations, the use of intraoperative monitoring and cautery, the use of magnetically controlled growing rods (MCGRs), and the use of an external remote controller to lengthen MCGRs. Across IPD types, consensus for the final postulates ranged from 94.4% to 100%. Overall, experts agreed that MCGRs can be surgically inserted and lengthened in patients with a variety of IPDs and provided guidance for the use of intraoperative monitoring and cautery, which varied between IPD types. Spinal deformity correction surgery often benefits from the use of intraoperative monitoring, monopolar and bipolar cautery, and MCGRs. The final postulates from this study can inform the perioperative and postoperative practices of spinal deformity surgeons who treat patients with both scoliosis and IPDs. V-Expert opinion.

The Incremental Clinical Benefit of Adding Layers of Complexity to the Planning and Execution of Adult Spinal Deformity Corrective Surgery.

For patients with surgical adult spinal deformity (ASD), our understanding of alignment has evolved, especially in the last 20 years. Determination of optimal restoration of alignment and spinal shape has been increasingly studied, yet the assessment of how these alignment schematics have incrementally added benefit to outcomes remains to be evaluated. Patients with ASD with baseline and 2-year were included, classified by 4 alignment measures: Scoliosis Research Society (SRS)-Schwab, Age-Adjusted, Roussouly, and Global Alignment and Proportion (GAP). The incremental benefits of alignment schemas were assessed in chronological order as our understanding of optimal alignment progressed. Alignment was considered improved from baseline based on SRS-Schwab 0 or decrease in severity, Age-Adjusted ideal match, Roussouly current (based on sacral slope) matching theoretical (pelvic incidence-based), and decrease in proportion. Patients separated into 4 first improving in SRS-Schwab at 2-year, second Schwab improvement and matching Age-Adjusted, third two prior with Roussouly, and fourth improvement in all four. Comparison was accomplished with means comparison tests and χ 2 analyses. Sevenhundredthirty-two. patients met inclusion. SRS-Schwab BL: pelvic incidence-lumbar lordosis mismatch (++:32.9%), sagittal vertical axis (++: 23%), pelvic tilt (++:24.6%). 640 (87.4%) met criteria for first, 517 (70.6%) second, 176 (24%) third, and 55 (7.5%) fourth. The addition of Roussouly (third) resulted in lower rates of mechanical complications and proximal junctional kyphosis (48.3%) and higher rates of meeting minimal clinically important difference (MCID) for physical component summary and SRS-Mental ( P < .05) compared with the second. Fourth compared with the third had higher rates of MCID for ODI (44.2% vs third: 28.3%, P = .011) and SRS-Appearance (70.6% vs 44.8%, P < .001). Mechanical complications and proximal junctional kyphosis were lower with the addition of Roussouly ( P = .024), while the addition of GAP had higher rates of meeting MCID for SRS-22 Appearance ( P = .002) and Oswestry Disability Index ( P = .085). Our evaluation of the incremental benefit that alignment schemas have provided in ASD corrective surgery suggests that the addition of Roussouly provided the greatest reduction in mechanical complications, while the incorporation of GAP provided the most significant improvement in patient-reported outcomes.

Delayed presentation of Wilkie’s syndrome after scoliotic curve correction surgery: a case report

BackgroundSuperior mesenteric artery (SMA) syndrome, also known as Wilkie’s syndrome, is a rare but serious complication following scoliosis correction surgery. It occurs as a result of mechanical compression of third part of duodenum between the SMA and aorta. This condition occurs most commonly in significantly underweight patients with deformities, and usually during the first week following spinal deformity corrective surgeries. The angle between the abdominal aorta and the SMA gets reduced following spinal lengthening during deformity correction surgery causing compression of third part of duodenum resulting in development of SMA syndrome.Case presentation.We present a case of 17-year-old male with congenital scoliosis with a 70-degree scoliotic curve who underwent spinal deformity correction surgery with posterior instrumented fusion. Post-operative course was uneventful and the patient was discharged after suture removal on post-operative day 15. The patient presented after 21-days of symptom onset on post-operative-day 51, with a 3 week history of post-prandial vomiting, abdominal pain and distension which resulted in rapid weight loss of 11 kg. A CT-angiogram showed obstruction at third part of duodenum. After reviewing clinical and radiological profile of the patient, a diagnosis of SMA syndrome was made. Conservative management was tried, but due to rapid deterioration of patient condition and symptoms of complete intestinal obstruction, the patient was treated surgically by gastro-jejunostomy and side-to-side jejuno-jejunostomy, which improved his condition.ConclusionSMA syndrome can occur much later than previously reported cases and with potentially life-threatening symptoms following scoliosis correction. Having a high index of suspicion, early recognition of condition and institution of appropriate treatment are essential to prevent occurrence of severe complications including risk of intestinal perforation and mortality. This case highlights management of delayed onset of SMA syndrome, with presentation further delayed after symptom onset, as is common in developing parts of the world, due to limited availability and accessibility of resources, and low socio-economic status of large segments of the population.

Highest Achievable Outcomes for Adult Spinal Deformity Corrective Surgery: Does Frailty Severity Exert a Ceiling Effect?

Retrospective single-center study. To assess the influence of frailty on optimal outcome following ASD corrective surgery. Frailty is a determining factor in outcomes after ASD surgery and may exert a ceiling effect on the best possible outcome. ASD patients with frailty measures, baseline, and 2-year ODI included. Frailty was classified as Not Frail (NF), Frail (F) and Severely Frail (SF) based on the modified Frailty Index, then stratified into quartiles based on two-year ODI improvement (most improved designated "Highest"). Logistic regression analyzed relationships between frailty and ODI score and improvement, maintenance, or deterioration. A Kaplan-Meier survival curve was used to analyze differences in time to complication or reoperation. A total of 393 ASD patients were isolated (55.2% NF, 31.0% F, and 13.7% SF), then classified as 12.5% NF-Highest, 17.8% F-Highest, and 3.1% SF-Highest. The SF group had the highest rate of deterioration (16.7%, P =0.025) in the second postoperative year, but the groups were similar in improvement (NF: 10.1%, F: 11.5%, SF: 9.3%, P =0.886). Improvement of SF patients was greatest at six months (ΔODI of -22.6±18.0, P <0.001), but NF and F patients reached maximal ODI at 2 years (ΔODI of -15.7±17.9 and -20.5±18.4, respectively). SF patients initially showed the greatest improvement in ODI (NF: -4.8±19.0, F: -12.4±19.3, SF: -22.6±18.0 at six months, P <0.001). A Kaplan-Meier survival curve showed a trend of less time to major complication or reoperation by 2 years with increasing frailty (NF: 7.5±0.381 yr, F: 6.7±0.511 yr, SF: 5.8±0.757 yr; P =0.113). Increasing frailty had a negative effect on maximal improvement, where severely frail patients exhibited a parabolic effect with greater initial improvement due to higher baseline disability, but reached a ceiling effect with less overall maximal improvement. Severe frailty may exert a ceiling effect on improvement and impair maintenance of improvement following surgery. Level III.

326 Factors Associated With the Maintenance of Cost-Effectiveness at 5 Years in Adult Spinal Deformity Corrective Surgery

INTRODUCTION: Substantial increase of costs in the surgical treatment of adult spinal deformity has given precedence to scrutinize the value it can provide hence cost-effectiveness (CE) is a vital analytical constituent. The analysis of factors associated with the durability of cost-effectiveness at 5 years has not been previously evaluated. METHODS: Adult spinal deformity (ASD) patients with baseline (BL) to 5-year (5Y) data were included. Cost calculation using PearlDiver database and CMS.gov definitions was used. Cost analysis was based on average DRG reimbursement rates. ODI was converted to SF-6D, with a 3% discount applied for residual decline in life expectancy. Cost per QALY gained at 2Y and 5Y was calculated. Threshold value for cost per QALY was $100,000. Patients that met 2Y (CE2+) were grouped based on meeting CE at 5Y(CE5+) or not(CE5-). Analysis based on meeting cost-effectiveness (CE) at 2Y and 5Y was conducted. Conditional-inference-tree (CIT) established cutoffs values for HRQLs. RESULTS: 299 patients with 5Y data were included. Major and minor complication rates were 11% and 47% respectively, while 26% underwent reoperation by 5Y. The mean cost of surgery was $91,095 ± $47,003, utility-gain of 0.091 ± 0.086, and QALY of 0.171 ± 0.183, CE of $118,976 ± $208,323. 85.5% of the cohort met CE at 2Y, 79.2% at 5Y, whereas 59.6% met both. Frailty was comparable at baseline but was worse in CE5- at 2Y. CIT depicted 2Y ODI &lt; 18 and SRS-22r &gt; 3.3 (both p &lt; 0.03) being associated with higher rates of C5+. Multivariable-regression depicted higher baseline CCI and pelvic tilt (PT) to be the strongest baseline predictors of not maintaining CE at 5Y (CCI OR: 1.821, p = 0.009) (PT OR: 1.079, p = .030). CONCLUSIONS: The majority that met cost-effectiveness at the 2 year went on to maintain it at 5 years. Lower baseline CCI and PT were strong predictive factors.

168 Sustenance of Substantial Clinical Benefit in Adult Spinal Deformity Corrective Surgery Patients: A Minimum 5-Year Outcomes Analysis

INTRODUCTION: Clinical outcomes for adult spinal deformity patients has been extensively reported on, however factors associated with sustaining two year (2Y) substantial clinical benefit (SCB) till five year (5Y) remains unclear. METHODS: ASD patients fused from at least L1 to sacrum with 5Y postoperative data were included. Good Outcome(GO) was defined as: no reoperation, mechanical failure, proximal junctional failure(PJF) based on Lafage criteria, and [meeting either: (1) SCB for Oswestry Disability Index(ODI)(decrease of &gt;18.8), or (2) ODI &lt;15 and Scoliosis Research Society(SRS-22r) Total&gt;4.5]. Multivariable analysis controlled for age, BMI, CCI, frailty, deformity, HRQLs, and surgical variations. RESULTS: 330 ASD patients were included. 42% achieved GO at 2Y(2+) while 47% at 5Y(5+) did. 71% of 2+ cohort attained 5+. In 2- cohort, 29% achieved 5+. Isolating 2+ cohort, assessing 5+ vs 5-: 5- had greater SVA deformity at 5Y (p &lt; .05). Regaining the level of activity postoperatively was associated with 4x higher odds of maintaining GO from 2Y to 5Y (p &lt; .05). The odds of achieving GO at 5Y in 2+ decreased by 47% for each additional comorbidity and decreased by 74% in those that had lower extremity paresthesias at BL (both p &lt; .05). Decreased number of levels fused, decreased correction in SVA and increased correction in PI-LL to be predictive of sustaining 2Y GO till 5Y (all p &lt; 0.05). CONCLUSIONS: Overall, 47% had substantial clinical benefit till 5Y. While 71% of patients at 2Y sustained good clinical outcome till 5Y, major contributors to its loss were adjacent segment changes and rod fracture. The odds of achieving SCB till 5Y decreased by nearly 50% for each additional comorbidity. Decreased levels fused along with decreased correction of SVA and increased correction in PI-LL were predictive of optimal sustaining of clinical outcomes.

1073 Prone Transpsoas (PTP)-LLIF Approach Versus Standard LLIF in Patients Undergoing Surgical Revision Following Adult Spinal Deformity Correction Surgery

INTRODUCTION: Both the prone transpsoas (PTP) and standard LLIF have been developed to facilitate minimally invasive (MIS) indirect decompression, alignment correction, and posterior instrumentation. METHODS: A multi-center cohort of all patients was identified and all relevant data were retrospectively collected. Preoperative standing 36” scoliosis radiographs were retrospectively reviewed for pelvic incidence (PI), lumbar lordosis (LL), and PI minus LL (PI-LL mismatch). Postoperative regional sagittal alignment parameters were measured using the first postoperative standing 36” scoliosis radiographs. Finally, multivariable analysis was performed to assess the primary outcome measure: postoperative change in regional sagittal alignment (PI-LL mismatch). RESULTS: Two-hundred and two (n = 202) patients were retrospectively identified and included for formal analysis. One-hundred and fifty one (n = 151, 74.8%) of the patients underwent PTP revision while 51 (25.2%) underwent standard LLIF revision. Univariate analysis demonstrated a greater value for baseline mean pre-operative PI-LL mismatch in the PTP versus standard LLIF cohort (21.4 vs. 10.45°; p = 0.0001). Furthermore, multiple linear regression demonstrated that the PTP approach enabled significantly greater PI-LL mismatch change (p = 0.0017) and that this change was associated with the number of levels fused (p = 0.0481) as well as percutaneous (vs. open) screw placement (p = 0.0193). Finally, multiple logistic regression identified standard LLIF (p = 0.0378), female sex (p &lt; 0.0001), non-osteoporotic bone density (p &lt; 0.0001), and younger age (p &lt; 0.0001) as predictive of postoperative PI-LL mismatch &lt; 10° (the threshold under which such mismatch is no longer regarded as clinically significant deformity). CONCLUSIONS: Ultimately, PTP-LLIF was associated with greater net improvement in postoperative PI-LL mismatch, the primary outcome measure of this study. The present retrospective analysis therefore corroborated results of previous studies in suggesting that the utility of PTP-LLIF is translatable to ASD revision surgery.