Correction Of Spinal Deformity Research Articles

Literature review: Early-onset Scoliosis and the Space Available for Lung (SAL) post-surgery

Background: Early-onset scoliosis (EOS) poses significant risks to thoracic development and pulmonary function in children due to the deformities’ impact on the space available for lung (SAL). Various surgical techniques, including growth-sparing methods like growing rods, vertical expandable prosthetic titanium ribs (VEPTR), and the Shilla system, aim to correct spinal deformities while allowing for thoracic growth. This literature review explores the efficacy of these interventions in improving SAL and lung function, as measured by forced vital capacity (FVC) and other pulmonary outcomes. Studies indicate that growth-friendly techniques are associated with substantial improvements in SAL, with growing rods showing an average 30% increase in thoracic volume and a corresponding improvement in pulmonary function. VEPTR has been similarly effective in increasing thoracic volume by 25% in patients with thoracic insufficiency syndrome. The Shilla system offers advantages in maintaining spinal correction while promoting growth but has been noted for potential complications like metal debris. Conclusion: Despite these advances, complications such as hardware failure and the need for revision surgeries remain concerns. This review underscores the importance of early surgical intervention to maximize thoracic volume and prevent long-term pulmonary impairment. However, further research is needed to assess the long-term outcomes of these surgical techniques, particularly in adulthood.

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.

Factors associated with rod fracture following surgery for adult spinal deformity: a single-center retrospective study.

Adult spinal deformity (ASD) has a significant impact on trunk balance and quality of life in the elderly. Postoperative rod fractures pose significant challenges, but the mechanisms of their occurrence are underexplored compared to other complications such as proximal junctional kyphosis. This study investigated factors associated with rod fracture in patients with ASD. A retrospective single-center study analyzed 110 adult patients who underwent spinal deformity correction between 2012 and 2020. Comparative analysis and univariate and multivariate Cox regression analyses were employed to identify factors associated with rod fracture. In this study, rod fracture occurred in 14.5% of patients. The rod fracture group exhibited a larger change in lumbar lordosis (LL), a higher proportion of patients with pre-operatively existing (pre-existing) vertebral fractures, and a greater percentage of patients with a rod diameter of 6mm or less compared to the non-rod fracture group. Univariate Cox regression analysis revealed that rod fracture was associated with pre-existing vertebral fracture, LL change, preoperative sagittal vertical axis, and preoperative pelvic tilt. Multivariate Cox regression analysis identified pre-existing vertebral fractures and the amount of LL change as independent factors associated with rod fractures. Pre-existing vertebral fractures and the magnitude of lumbar lordosis correction are independent risk factors for rod fracture following ASD surgery. Surgeons should consider these factors during preoperative planning to reduce the risk of postoperative rod fracture. IV.

Perioperative and early complications of extended instrumental fixation for spinal deformity in children: what does the application of the Clavien – Dindo classification reveal and what questions does it raise?

Objective. To analyze complications of extended posterior instrumental fixation for spinal deformity in children in accordance with the Clavien – Dindo classification and to assess its information content and limitations.Material and Methods. A retrospective single-center cohort study included 136 patients aged from 1 year to 17 years 11 months consecutively operated in 2020–2023 for thoracic and lumbar spine deformities associated with congenital, neuromuscular, syndromic, idiopathic scoliosis and Scheuermann’s kyphosis. At least four spinal motion segments were included in the zone of posterior instrumental fixation. All perioperative events and postoperative complications noted in the medical records were registered in accordance with the Clavien – Dindo classification. An analysis of factors influencing the development of complications of grade IIIB and higher was carried out.Results. With a total apparent high number of complications/events (55 or 40.4 % of the number of operations), the vast majority of them correspond to grade I–II (41; 30.1 %) and do not affect the tactics and outcome of treatment. Complications of grade III and IV were noted in 13 (9.6 %) cases, and of grade V – in 1 (0.7 %) case. The influence of deformity etiology, gender, age or underweight on the risk of grade IIIB and IVA complications was not revealed, which may be due to the limited number of observations. The installation of more than 18 transpedicular screws, which correlated with surgery duration and blood loss volume, was significant for the development of such complications. The results obtained were compared with those presented in the literature, the information content and limitations of the use of the Clavien – Dindo classification in spine surgery were discussed.Conclusion. A significant part of the complications of spinal deformity correction in children is conventionally not taken into account in domestic practice and, accordingly, cannot be prevented. The use of the Clavien – Dindo classification allows estimating the frequency of complications that potentially do not affect (grade I–II) and affect (grade III–IV) the tactics of postoperative treatment and outcomes. The installation of 18 or more supporting elements of instrumentation is directly related to surgery duration, intraoperative blood loss volume and the risk of developing grade IIIB and IVA complications. Larger data sets are needed for a more objective analysis of the risk of severe complications for each nosology.

Pediatric obesity and adverse outcomes following deformity correction surgery for adolescent idiopathic scoliosis: A cross-sectional analysis using 2015-2019 NIS data.

Obesity in the pediatric population has been a growing medical concern over the last few decades with a prevalence of 19.7% as of 2017-2020. Obesity is a risk factor for greater scoliotic curves and failure of conservative therapy for adolescent idiopathic scoliosis (AIS). Establishing a correlation between obesity and a wide variety of adverse outcomes following scoliosis surgery can assist in the preoperative consultation with the family and proper optimization of the patient for scoliosis fusion surgery. The National Inpatient Sample (NIS) was used to access inpatient data from 2015 to 2019. Pediatric patients with idiopathic scoliosis admitted for spinal deformity correction via posterior spinal fusion of over 8 levels were identified. Patients were stratified based on the comorbid diagnosis of obesity. Variables that were significantly associated with outcomes (p < 0.05) were used in a multivariable logistic regression to control for confounders. Backwards stepwise p-value removal was used to build the final model and model fit was assessed using the area under the curve. A total of 855 obese and 17,285 non-obese pediatric patients undergoing posterior instrumented fusion for scoliotic deformity correction were identified. The obese group was associated with a higher rate of SSI (0.6% vs 0.1%, p < 0.001), UTI (1.2% vs. 0.3%, p < 0.001), and AKI (0.6% vs 0.1%, p = 0.12) compared to the normal BMI group. Obese patients were also more likely to have a non-routine discharge when compared to non-obese (4.7% vs. 2.3%, p < 0.001). The rate of having more than one complication occurring postoperatively was higher in the obese group, however, this finding was not significant (0.6%, vs 0.4%, p = 0.385). On multivariate regression analysis, obesity was positively associated with SSI (OR = 2.758, CI = 0.999-7.614, p = 0.050), UTI (OR = 2.221, CI = 1.082-4.560, p = 0.030), non-routine discharge (OR = 1.515, CI = 1.070-2.147, p = 0.019), and an extended LOS (OR = 1.869, CI = 1.607-2.174, p < 0.001). Obesity was associated with postoperative blood transfusion, SSI, UTI, increased length of stay, and non-routine discharge after pediatric AIS deformity surgery. In addition to the increased morbidity seen in obese patients, we also identified the significantly increased cost of care for this group when compared to non-obese patients. These data should be used for a robust preoperative risk assessment and evidence for BMI optimization prior to deformity correction for AIS.

Prevalence and Clinical Impact of Coronal Malalignment Following Circumferential Minimally Invasive Surgery (CMIS) for Adult Spinal Deformity Correction.

Retrospective study. To determine prevalence and clinical importance of patients who had postoperative CM after CMIS for ASD correction. We reviewed patients who underwent CMIS technique. Inclusion criteria were patients who were diagnosed with ASD, which is defined as having at least one of the following: coronal Cobb angle >20, SVA >50mm, PI-LL >10, PT >20. They underwent >4 spinal levels fusion with CMIS technique and had at least 1-year follow-up. Preoperative and 1-year postoperative radiographs and clinical outcome measures (VAS, ODI, and SRS-22 scores) were used to make the comparisons. 120 patients were included. Radiographic outcomes, including CVA, coronal Cobb angle, LSF curve, SVA, LL, and PI-LL, and clinical outcomes, were significantly improved postoperatively in each of the 3 preoperative subgroups (Bao type A, B, and C). At 1-year post-operation, 10 patients (12.4 %) of type A turned out to be CM, 4 patients (21.1%) of type B, and 8 patients (40%) of type C remained CM. Comparing coronally aligned (CA) to coronally mal-aligned patients at 1-year follow-up in each coronal subtype revealed that clinical and radiographic outcomes were comparable. CMIS technique significantly improves radiographic and clinical outcomes for ASD patients. Incidence rates of postoperative CM were similar to open surgery. Type C patients were at risk of postoperative CM than types A and B. However, most 1-year outcomes were not significantly different between postoperative CA and CM patients regardless of the preoperative coronal alignment characteristics except ODI scores in type A.

Efficacy of a new customized navigation template for placement of transpedicular screws for unilateral access in children with congenital spinal deformity and thoracic malformation

BACKGROUND: Surgical treatment of congenital spinal deformities combined with thoracic development anomalies in children is an urgent and a complex problem in surgical practice. The surgical method of correcting congenital deformities caused by segmentation disorder of the lateral surfaces of vertebral bodies and unilateral rib synostosis is aimed at correcting the existing deformity using a transpedicular system. This technique is effective for treating this group of patients. However, it requires precise and accurate installation of the supporting elements of the metal structure owing to the high risk of damage to the neurovascular structures in the area of surgical intervention. A solution to this problem is the use of an individualized guide template with rib support for unilateral access in children with congenital deformities of the thorax and spine. AIM: To perform a comparative analysis of the results of using an individual rib-supported guide template for transpedicular screw placement and the “free hand” method in children during surgical correction of congenital spinal deformities accompanied by thoracic development anomalies. MATERIALS AND METHODS: The study included 14 patients who underwent surgical treatment for congenital deformity of the thoracic spine against the background of segmentation disorder of the lateral surfaces of the vertebral bodies in combination with thoracic anomalies. The patients were divided into two groups. Group 1 included six patients operated on using a new navigation template guide, and group 2 consisted of eight patients who underwent installation of support elements using the “free hand” method. The following parameters were compared: time spent at the stage of formation of bone canals for the support elements of the metal structure and accuracy and correctness of support element installation. Clinical data included demographic information and the size of the scoliotic arch, number of support elements, and presence of complications. Statistical analysis using Student’s t-test for unpaired samples or Mann–Whitney test was used to compare results. RESULTS: Data obtained in the course of the study confirmed the high efficiency and accuracy and showed that the use of the template reduces the time of bone canal formation, increases the accuracy, and provides greater correctness of the position of the supporting elements compared to the “free hand” method, which increases the efficiency and safety of surgical treatment. CONCLUSIONS: The developed template guide with support on the rib for the installation of the supporting elements of the metal structure in the surgical treatment of children with congenital deformity of the thoracic spine in combination with thoracic development anomaly showed better results compared to the use of the “free hand” method.

Analysis of vertebrotomy treatment in children with congenital scoliosis with unsegmented rod and rib synostosis

BACKGROUND: Congenital anomalies of vertebral development account for 2%–11% of cases in the general structure of nosologies that cause spinal deformity. An unsegmented rod (unilateral violation of vertebral segmentation) is attributed to a prognostically unfavorable malformation. Rib synostosis causes the development of thoracic insufficiency syndrome. AIM: To analyze the results of treatment of children with congenital scoliosis caused by an unsegmented rod and rib synostosis by vertebrotomy. MATERIALS AND METHODS: This cohort, retrospective, monocenter study evaluated the treatment results of 55 patients. The patients were divided into two groups: group 1, children aged 2–8 years, the scope of intervention was wedge-shaped osteotomy of a non-segmented rod at the apex of the deformity, and group 2, children aged 8–18 years, the scope of intervention was wedge-shaped osteotomy at the apex of the deformity and two linear osteotomies of a non-segmented rod in the cranial and caudal directions. Clinical, radiological, and statistical research methods were used. RESULTS: Significant correction of scoliosis was achieved in 65.5% of patients aged 2–7 years (group 1) and 56.3% in children aged 8–18 years (group 2). Hypokyphosis of the thoracic spine was observed in the patients. The percentage of correction of kyphosis was 21.1% in group 1 and 19.1% in group 2. Lung volume increased by 27.9% (p = 0.01776) in group 1, and lung volume on the concave side increased by 23.5% (p = 0.04975) and on the convex side by 29.6% (p = 0.01073). Improvement in the overall respiratory impedance reached 47.3% (p 0.05). In group 2, a insignificant increase was found in VVC by 12.6% (p = 0.3509) and FEV1 by 8.7% of the initial (p = 0.1534), as well as an increase in total lung volume of 13.3% (p = 0.1527) and the contribution of the lung along the concave side of 18.8% (p = 0.1535), and the lung along the convex side was 8.4% (p = 0.169), indicating no significant impact on lung development and function. CONCLUSIONS: In children with spinal deformity caused by a non-segmented rod with normal respiratory function, vertebrotomy at the apex of the deformity with subsequent correction and stabilization of the spinal deformity is recommended. Performing simultaneous multilevel osteotomies of a non-segmented rod allows for significant correction of rigid spinal deformity.

Acute postoperative complications after spine deformity correction in patients with Down syndrome.

Down syndrome, or trisomy 21, is the most diagnosed chromosomal abnormality and is associated with multiple orthopedic concerns, including scoliosis. We sought to examine the surgical treatment of scoliosis associated with Down syndrome with an emphasis on specific complications in this population. A retrospective review of 13 patients with Down syndrome who underwent surgical intervention for spinal deformity between 2000 and 2018 were identified. Postoperative complications were classified using the modified Clavien-Dindo-Sink system. Perioperative and final follow-up radiographic data were analyzed. The mean age at surgery was 14.2 years (11-19) with a mean follow-up of 3.6 years (0.4-6.2) at the time of data collection. Seven (54%) patients had postoperative complications, all related to wound healing. Three patients (23%) had major complications (Clavien-Dindo-Sink grade ≥3). These included one deep surgical site infection, one hematoma, and one seroma, all requiring surgical drainage. Four additional patients (31%) had minor complications (Clavien-Dindo-Sink grade ≤2). Surgical intervention for scoliosis in patients with Down syndrome is associated with high complication rates despite the use of more modern surgical techniques and implant types. Complications in this cohort primarily involved wound healing, whereas previous studies described high rates of postoperative implant failure, pseudoarthrosis, and significant curve progression, which were not experienced by the patients in this study. Although the etiology of wound-related complications is unknown, awareness of this risk may help surgeons optimize surgical technique, postoperative monitoring, and preoperative counseling of families. IV-single-institution retrospective case series.

Early clinical outcomes and medical complications following long segment fusion for adult spinal deformity with and without three column osteotomy

BackgroundSurgical treatment of adult spinal deformity (ASD) commonly involves long-segment fusion with or without three column osteotomies (3CO) to provide satisfactory correction of sagittal and coronal balance. While some clinical studies have implicated 3CO as a driver of high surgical complication rates, these prior investigations are limited by small sample size. Herein, we compare early outcomes and adverse events in patients undergoing long segment posterior spinal fusion for ASD with and without 3CO. MethodsA multicenter administrative database was queried for patients undergoing elective posterior spinal fusion for ASD. Patients were stratified based upon long segment fusion with and without 3CO. Preoperative patient demographics, procedural characteristics, hospitalization events, and postoperative complication rates were evaluated. Student's t-test and Fisher's exact test were utilized where appropriate to compare differences between the two groups for continuous and categorical variables. Results340 cases met the inclusion criteria, of which 156 involved 3CO. Patients who required 3CO had a lower rate of preoperative diabetes (22.3 % vs 10.3 %, p = 0.003), higher rates of non-home discharge (26.2 % vs 57.1 %, p < 0.001), longer operation time (245.62 ± 9.45 vs. 434.40 ± 11.65, p < 0.001), and longer length of stay (4.17 ± 0.66 vs. 7.76 ± 0.83, p < 0.001). In terms of complications, 3CO patients had higher rates of deep surgical site infection (0 % vs 3.2 %, p = 0.02), reintubation (0 % vs 4.5 %, p = 0.004), inability to wean off ventilator (0 % vs 2.6 %, p = 0.04), and perioperative blood transfusion (20.1 % vs 76.3 %, p < 0.001). ConclusionsIn this retrospective analysis, posterior 3CO was frequently undertaken but associated with higher risk for postoperative adverse events following spinal deformity correction.

Magnetic resonance imaging evaluation of the cerebellar tonsil position before and after posterior spinal fusion in adolescent idiopathic scoliosis.

Chiari malformation type I(CM-I) is one of the most common neurological malformations observed in patients with adolescent idiopathic scoliosis (AIS). It remains uncertain whether AIS patients without neurological symptoms require CM-I decompression before undergoing spinal corrective surgery to prevent cerebellar tonsil herniation and potential neurological complications. This study aims to assess variations in the position of the cerebellar tonsil after posterior spinal fusion (PSF) in neurologically intact patients with AIS. We retrospectively evaluated 40 patients with AIS who underwent posterior spinal fusion (PSF) without neurological symptoms. Sagittal hindbrain MRIs were performed before and after spinal surgery. The cerebellar tonsil's position relative to the foramen magnum was measured using the method described by Aboulezz (J Comput Assist Tomogr 1985). We assessed variations in the cerebellar tonsil position concerning spinal correction and elongation after PSF. The average preoperative magnitude of the scoliotic curve was 53.15 degrees (SD 10.46 degrees), and that of thoracic kyphosis was 35.42 degrees (SD 12.38 degrees). In the immediate postoperative period, the average magnitudes were 7.45 degrees (SD 7.33 degrees) and 27.87 degrees (SD 9.03 degrees), respectively. The average correction achieved with PSF was 86% in the coronal plane (p < 0.00001). The average length of the spine in the coronal plane was 44.5cm (SD 5.25cm) preoperatively and 48.27cm (SD 4.40cm) postoperatively (p < 0.00001). The average length of the vertebral column in the sagittal plane was 50.87cm (SD 4.47cm) preoperatively and 55.13cm (SD 3.27cm) postoperatively (p < 0.00001). No significant difference was observed in the position of the cerebellar tonsil in the measurements taken before and after spinal deformity correction (p = 0.6042). In 10 out of 40 patients, caudal displacement of the cerebellar tonsil was observed after PSF. In 28 patients, no variation in the position of the cerebellar tonsil was observed, and in 2, cephalic displacement was noted. In AIS patients with a normal position of the cerebellar tonsil undergoing posterior spinal fusion, there is no significant change in their positionafter surgery. Our analysis did not reveal any correlation between curve correction, spine elongation, and variations in the cerebellar tonsil position. The position of the cerebellar tonsil remained largely unchanged after PSF in AIS patients without neurological symptoms. Further studies would be necessary to determine whether surgical decompression is required in asymptomatic patients with CM-I before undergoing surgery to correct spinal deformity.

Blood loss during three column osteotomies: influence on outcomes and mitigation strategies.

Three column osteotomies (3CO) are a powerful tool for the correction of rigid sagittal spinal deformities. However, 3CO surgeries are technically demanding procedures that are associated with prolonged operative times, large amounts of intraoperative blood loss, and high rates of post-operative neurological and medical complications. The purpose of this retrospective cross-sectional study is to delineate the effects of blood loss, blood transfusion, and tranexamic acid use on perioperative outcomes following 3CO. Patients undergoing 3CO between 2014 and 2021 were identified using current procedural terminology (CPT) codes, and charts were reviewed for demographics, surgical characteristics, and post-operative length of stay (LOS). Statistical analysis included T-tests for continuous characteristics and χ2 testing for categorical characteristics. Regression models were used to further investigate relationships between outcomes and variables of interest. Forty-two patients met inclusion criteria. Increased intensive care unit (ICU) LOS was positively correlated with increased operative length (P=0.02), percent estimated blood volume (EBV) lost (P=0.02), and number of units of red blood cell transfusion (P<0.001). Increased hospital LOS was associated with increased number of intraoperative blood transfusions (P=0.01). Linear regression analyses controlling for age, gender, and American Society of Anesthesiologists (ASA) class showed that each 21% increase in EBV loss was associated with a one day increase in ICU LOS (P=0.01). Similarly, each additional unit of packed red blood cells transfused was associated with 0.728 day increase in hospital LOS. Increased intraoperative blood loss was associated with longer ICU stays. Red blood cell transfusions were also associated with increased hospital and ICU LOS. No variables of interest related to intraoperative blood loss or blood transfusion were associated with readmission or reoperation at any time point. These findings highlight the need for continued focus on surgical techniques and adjuncts that can minimize blood loss and transfusion requirements.

T1 Pelvic and Lumbar Pelvic Angles Normative Values: A Prospective Cohort Study of 472 Asymptomatic Volunteers.

Cross-sectional analysis of a prospectively enrolled cohort. Determine the normative values of the T1 Pelvic Angle (TPA) and Lumbar Pelvic Angle (LPA) in an asymptomatic cohort of volunteers. The TPA and LPA have been introduced as sagittal spino-pelvic parameters to guide correction of adult spinal deformity. Suggested values for these parameters were derived from linear regressions based on Oswestry Disability Index scores from adult spinal deformity patients. While a few studies have evaluated the normative value of TPA, none have evaluated the LPA in asymptomatic individuals. TPA and LPA were measured on radiographs of 472 asymptomatic volunteers between 20 and 40 years old. TPA and LPA were calculated as originally described from the centroid of T1 and L1 respectively, to the center of the femoral head to the midpoint of the sacral endplate. TPA and LPA were also evaluated using the midpoint of the superior endpoint as a surrogate to the centroid of the vertebra to compare these two measurement techniques. TPA and LPA normative values were respectively 7.3 [6.8-7.8] and 6.3o [5.9-6.7]. There was no statistically significant difference between using the centroid of T1 or L1 versus using the midpoint of the superior endplate with respective results of 7.5o [7.0-8.0] (P=0.55) and 6.1o [5.6-6.5] (P=0.43). TPA was significantly different between Roussouly types 1-2-3 versus type 4 with respective results of of 6.7o, 7.2o, 6.5o and 9.2o (P<0.001). The same difference was observed for the LPA with normative results of 3.8o, 5.1o, 5.8o and 9.3o (P<0.001), respectively, for Roussouly types 1,2,3 and 4. TPA and LPA normative values are 7o and 6o, respectively, and vary between Roussouly morphotypes 1,2 and 3 versus type 4. Using the midpoint of the superior endplate of T1 and L1 versus the centroid yielded similar results and therefore could be easier to use intraoperatively.

Application of neurophysiological studies for diagnosis and justification of neurosurgical treatment of kyphotic deformity due to the congenital anomaly of the spine

The results of a comprehensive clinical, radiological and neurophysiological study were analyzed in patients with kyphotic deformity of the thoracic and lumbar spine due to a congenital anomaly of vertebral development in the dynamics of surgical treatment. It has been established that congenital kyphotic spinal deformity is accompanied by vertebromedullary conflict with a high risk of the occurrence and/or worsening of spinal neurological disorders. The study of the data obtained made it possible to evaluate deformation lesions of the spine from the standpoint of qualitative and quantitative severity of pathological changes in the conduction function in the system of nervous tracts of the spinal cord, which was an objective argument in justifying the indications for surgical correction and its methodological implementation, as well as an important neurophysiological criterion for subsequent dynamic monitoring of clinical conditions of a patient.It was found that the surgical treatment allowed us to improve and subsequently stabilize the functional state of the spinal cord as a consequence of the achieved significant correction of congenital kyphotic spinal deformity.

Patient-Specific Rods in Adolescent and Adult Spinal Deformity Surgery: A Narrative Review.

Spinal deformity surgery often requires complex surgical interventions that can have a drastic effect on both patient quality of life and functional capacity. Modern-day corrective solutions for these deformities include spinal osteotomies, pedicle screw instrumentation, and dual/multirod constructs. These solutions are efficacious and are currently considered standard practice for spinal surgeons, but they lack individualization. Patient-specific rods (PSRs) are a novel technology that attempts to offer a personalized approach to spinal deformity correction based on preoperative computerized tomography scans. Moreover, PSRs may offer several advantages to conventional rods, which include achievement of desired rod contour angles according to surgical planning alignment goals, reduced operative time, and reduced blood loss. In adolescent idiopathic scoliosis, those instrumented with PSR have observed coronal Cobb reductions up to 74%. In adult spinal deformity, PSRs have offered superior correction in radiographic parameters such as sagittal vertical axis and pelvic incidence minus lumbar lordosis. However, there still remains a paucity of research in this area, mainly in health care expenditure, cost-effectiveness, and longitudinal clinical outcomes. The purpose of this article is to survey the current body of knowledge of PSR instrumentation in both adolescent and adult spinal deformity populations. The current strength, limitations, and future directions of PSRs are highlighted throughout this article.

Corner Osteotomy as the more Advanced Approach to Deformity Correction in Adult Spinal Deformity: A Retrospective Comparative Study Between Two Osteotomy Techniques.

A retrospective study. To investigate the usefulness of corner osteotomy (CO) in patients with adult spinal deformity (ASD) by comparing with pedicle subtraction osteotomy (PSO) for lordosis correction. PSO remains a valuable procedure for patients with ASD, but it has a limit to obtaining correction angles exceeding 45° in patients with a large pelvic incidence or with previous spinal fusion surgeries. Theoretically, CO can exceed the limitation of PSO and can achieve a wide range of correction angles. However, no study has analyzed the clinical data and usefulness of CO. This study included 115 patients (mean age 71.1y, mean follow-up period 78.9mo) with ASD who underwent deformity correction using PSO or CO. Comparative analysis was performed on spinopelvic parameters including segmental angle (SA) around the osteotomy site, and clinical and surgical assessment between the PSO and corner groups. In the corner group, the postoperative SA (35° vs. -39.3°, P=0.004) and the degree of SA correction (34.8° vs. 39.7°, P=0.004) were greater, and a broader range of SA correction was also possible (18-51° vs. 18-61°). Although the operative time was longer in the corner group (316.8min vs. 342.3min, P=0.014), the estimated blood loss (EBL) was lower (2841.3mL vs. 2465.4mL, P=0.032). There was no difference in major complication rates, but the frequency of rod fracture (RF) was lower in the corner group (36/27 vs. 1/51, P<0.05). CO showed a greater SA correction and achieved a broader range of SA correction angles than PSO with no difference in the incidence of major complications. In addition, the EBL and the frequency of RF were lower. Based on these results, we expect that CO can serve as a promising surgical alternative to PSO for spinal deformity correction among patients with ASD.

50. Disparities in presentation and outcomes of symptomatic proximal junctional kyphosis based on over- and under-correction in adult spinal deformity corrections

50. Disparities in presentation and outcomes of symptomatic proximal junctional kyphosis based on over- and under-correction in adult spinal deformity corrections

52. Limiting blood loss and estimating cell salvage volume for return in adult spinal deformity correction

52. Limiting blood loss and estimating cell salvage volume for return in adult spinal deformity correction

116. Machine learning clustering of preoperative fitness and its prognostic value following adult spinal deformity correction

116. Machine learning clustering of preoperative fitness and its prognostic value following adult spinal deformity correction

P123. Determinants of cost-effectiveness in minimally invasive surgery for adult spinal deformity correction

P123. Determinants of cost-effectiveness in minimally invasive surgery for adult spinal deformity correction