Correction Of Sagittal Alignment Research Articles

Cage Obliquity in Oblique Lumbar Interbody Fusion-How Common Is It and What Are the Effects on Fusion Rates, Subsidence, and Sagittal Alignment? A Computed Tomography-Based Analysis.

Oblique lumbar interbody fusion (OLIF) through a prepsoas approach was identified as an alternative to alleviate complications associated with direct lateral interbody fusion. Cage placement is known to influence cage subsidence and fusion rates due to suboptimal biomechanics. There are limited studies exploring cage obliquity as a potential factor influencing fusion outcomes. Hence, our objective was to assess the effects of cage obliquity and position on fusion rates, subsidence, and sagittal alignment in patients who underwent OLIF. Patients who underwent OLIF for levels L1 to L5 in our center, performed by a single surgeon and with a minimum of 12 months of follow-up, were included in the study. Cage obliquity and sagittal placement were measured, and their correlation with fusion, subsidence, and sagittal alignment correction was assessed. Fusion and subsidence were evaluated using the Bridwell Criteria and Marchi Criteria, respectively. Among the included patients (age, 67.5 ± 7.93 years; 16 men and 37 women), 97 fusion levels were studied. The mean cage obliquity was 4.2° ± 2.8°. Ninety-six levels (99.0%) were considered to have achieved fusion with a Bridwell score of 1 or 2. Eighty-one (83.5%), 14 (14.4%), and 2 (2.06%) operated levels had a Marchi score of 0, 1, and 2, respectively. A Marchi grade of 1 or higher was considered indicative of significant subsidence. There was good improvement in both the segmental lordosis angle (4.2° ± 5.7°; P < 0.0001) and disc height (4.5 ± 3.8 mm; P < 0.0001). Cage placement did not have any statistical correlation with fusion rates, subsidence, or sagittal alignment. Our results indicate that OLIF facilitates appropriate cage placement with only a minor degree of cage obliquity, typically less than 20°. This minor obliquity does not lead to lower fusion rates, increased subsidence, or sagittal malalignment. Despite subsidence being common, the majority of these cases resulted in complete fusion.

Sequential correction of sagittal vertical alignment and lumbar lordosis in adult flatback deformity

BackgroundFlatback deformity, or lumbar hypolordosis, can cause sagittal imbalance, causing back pain, fatigue, and functional limitation. Surgical correction through osteotomies and interbody fusion techniques can restore sagittal balance and relieve pain. This study investigated sagittal vertical alignment (SVA) and lumbar lordosis correction achieved through sequential procedures on human spine specimens. MethodsHuman T10-sacrum specimens were stratified into 2 groups: degenerative flatback specimens had smaller L1-S1 lordosis compared to the iatrogenic group (26.1°±15.0° vs. 47.8°±19.3°, p<.05). Specimens were mounted in the apparatus in simulated standing posture with a nominal sacral slope of 45 degrees and subjected to a 400N compressive follower preload. Sequential correction of degenerative lumbar flatback deformity involved: anterior lumbar interbody fusion (ALIF) at L5-S1, ALIF at L4-5, lateral lumbar interbody fusion (LLIF) at L2-3 and L3-4, and posterior column osteotomy (PCO) at L2-3 and L3-4. In iatrogenic specimens, flatback deformity was created by performing a posterior in-situ immobilization using pedicle screw instrumentation at L4-L5-S1 followed by distraction across the pedicle screws. We then performed LLIF at L2-3 and L3-4, followed by PCO at L2-3 and L3-4. ResultsStatistically significant incremental corrections were noted in SVAs and lordosis after L5-S1 ALIF, L4-5 ALIF, and PCO in degenerative flatback specimens. For the iatrogenic group, statistically significant worsening was noted in measures of standing alignment after L4-L5-S1 hypolordotic fusion. Subsequent LLIF at L2-3 and L3-4 did not significantly improve sagittal alignment. However, after PCO at L2-3 and L3-4, final alignment parameters were not significantly different than preoperative baseline values prior to hypolordotic fusion. ConclusionsALIF cages in the lower lumbar segments significantly improved sagittal alignment in degenerative flatback specimens. In the upper lumbar segments, LLIF cages alone were ineffective at enhancing lumbar lordosis. LLIF cages in conjunction with PCO improved alignment parameters in degenerative and iatrogenic flatback deformities.

Importance of the lumbar paraspinal muscles on the maintenance of global sagittal alignment after lumbar pedicle subtraction osteotomy.

There are limited data about the influence of the lumbar paraspinal muscles on the maintenance of sagittal alignment after pedicle subtraction osteotomy (PSO) and the risk factors for sagittal realignment failure. The authors aimed to investigate the influence of preoperative lumbar paraspinal muscle quality on the postoperative maintenance of sagittal alignment after lumbar PSO. Patients who underwent lumbar PSO with preoperative lumbar MRI and pre- and postoperative whole-spine radiography in the standing position were included. Spinopelvic measurements included pelvic incidence, sacral slope, pelvic tilt, L1-S1 lordosis, T4-12 thoracic kyphosis, spinosacral angle, C7-S1 sagittal vertical axis (SVA), T1 pelvic angle, and mismatch between pelvic incidence and L1-S1 lordosis. Validated custom software was used to calculate the percent fat infiltration (FI) of the psoas major, as well as the erector spinae and multifidus (MF). A multivariable linear mixed model was applied to further examine the association between MF FI and the postoperative progression of SVA over time, accounting for repeated measures over time that were adjusted for age, sex, BMI, and length of follow-up. Seventy-seven patients were recruited. The authors' results demonstrated significant correlations between MF FI and the maintenance of corrected sagittal alignment after PSO. After adjustment for the aforementioned parameters, the model showed that the MF FI was significantly associated with the postoperative progression of positive SVA over time. A 1% increase from the preoperatively assessed total MF FI was correlated with an increase of 0.92 mm in SVA postoperatively (95% CI 0.42-1.41, p < 0.0001). This study included a large patient cohort with midterm follow-up after PSO and emphasized the importance of the lumbar paraspinal muscles in the maintenance of sagittal alignment correction. Surgeons should assess the quality of the MF preoperatively in patients undergoing PSO to identify patients with severe FI, as they may be at higher risk for sagittal decompensation.

Philosophies and Surgical Techniques for High-Grade Spondylolisthesis Treatment with Literature Review.

High-grade spondylolisthesis is defined as cases with more than 50% displacement and spondylolisthesis with Meyerding grade III and higher. The surgical management of high-grade spondylolisthesis is highly controversial. Many surgical methods have been reported such as posterior in situ fusion, instrumented posterior fusion with or without reduction, combined anterior and posterior procedures, spondylectomy with reduction of L4 to the sacrum (for spondyloptosis), and posterior interbody fusion with trans-sacral fixation. The literature has recently mentioned minimally invasive transforaminal lumbar interbody fusion for high-grade spondylolisthesis. This study aimed to review the recent literature that describes the surgical outcomes associated with various surgical techniques used for high-grade spondylolisthesis. Recent articles were searched on search engines such as PubMed and Google Scholar using keywords such as "high-grade spondylolisthesis," "surgical techniques," and "complications." The surgical management of high-grade spondylolisthesis is an area of significant controversy. The literature is replete with regards to the need for reduction, decompression, levels of fusion, the nature of instrumentation, surgical approaches including open, minimally invasive, and "mini-open" procedures, and various techniques for reducing the slip and fusion strategy. The three basic options of high-grade spondylolisthesis include in-situ fusion, partial reduction and fusion, and complete reduction. Various techniques have been described for high-grade spondylolisthesis. Spine deformity study group classification gives guidelines about balanced and unbalanced pelvis and advises reduction and fusion in case of unbalanced pelvis for correction of biomechanical and global sagittal alignment. Each of the surgical techniques has its advantages and disadvantages. However, individual authors' experience, skill levels, and anatomic reduction with fusion techniques have yielded encouraging results.

Correction of Spinal Sagittal Alignment after Posterior Lumbar Decompression: Does Severity of Central Canal Stenosis Matter?

This study adopted a retrospective study design. Our study aimed to investigate the impact of central canal stenosis severity on surgical outcomes and lumbar sagittal correction after lumbar decompression. Studies have evaluated sagittal correction in patients with central canal stenosis after lumbar decompression and the association of stenosis severity with worse preoperative sagittal alignment. However, none have evaluated the impact of spinal stenosis severity on sagittal correction. Patients undergoing posterior lumbar decompression (PLD) of ≤4 levels were divided into severe and non-severe central canal stenosis groups based on the Lee magnetic resonance imaging (MRI) grading system. Patients without preoperative MRI or inadequate visualization on radiographs were excluded. Surgical characteristics, clinical outcomes, and sagittal measurements were compared. Multivariate logistic regression was performed to determine the predictors of pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), and pelvic incidence minus lumbar lordosis (PI-LL). Of the 142 patients included, 39 had severe stenosis, and 103 had non-severe stenosis. The mean follow-up duration for the cohort was 4.72 months. Patients with severe stenosis were older, had higher comorbidity indices and levels decompressed, and longer lengths of stay and operative times (p <0.001). Although those with severe stenosis had lower lordosis, lower SS, and higher PI-LL mismatch preoperatively, no differences in Delta LL, SS, PT, or PI-LL were observed between the two groups (p >0.05). On multivariate regression, severe stenosis was a significant predictor of a lower preoperative LL (estimate=-5.243, p =0.045) and a higher preoperative PI-LL mismatch (estimate=6.192, p =0.039). No differences in surgical or clinical outcomes were observed (p >0.05). Severe central lumbar stenosis was associated with greater spinopelvic mismatch preoperatively. Sagittal balance improved in both patients with severe and non-severe stenosis after PLD to a similar degree, with differences in sagittal parameters remaining after surgery. We also found no differences in postoperative outcomes associated with stenosis severity.

Risk factors of postoperative coronal malalignment following long-segment spinal fusion surgery in which multilevel lateral lumbar interbody fusion was used for degenerative lumbar kyphoscoliosis.

In patients with adult spinal deformity, especially degenerative lumbar kyphoscoliosis (DLKS), preoperative sagittal malalignment and coronal malalignment (CM) often coexist. Lateral lumbar interbody fusion (LLIF) has recently been widely chosen for DLKS treatment due to its minimal invasiveness and excellent sagittal alignment correction. However, postoperative CM may remain or occur due to an oblique takeoff phenomenon following multilevel LLIF, resulting in poor clinical outcomes. The authors investigated the risk factors for postoperative CM after long-segment fusion corrective surgery in which multilevel LLIF was used in patients with DLKS. Fifty-four consecutive patients with DLKS, main Cobb angle ≥ 20°, and lumbar lordosis ≤ 20° who underwent corrective spinal fusion surgery, including extreme lateral interbody fusion at ≥ 3 segments, were included at the authors' institute between April 2014 and October 2019. Patients who underwent suitable 3-column osteotomy, classified as grade 3-6 per the Scoliosis Research Society-Schwab criteria, were excluded. Patients were divided into CM and non-CM groups based on postoperative CM evaluated using standard standing-position radiographs obtained 2 years postoperatively. CM was defined as an absolute C7-CSVL (deviation of C7 plumb line off central sacral vertical line; calculated by defining the convex side of the CSVL as positive numerical values) value of ≥ 3.0 cm. Patient demographics and preoperative sagittal alignment parameters were evaluated. The following variables were measured to assess coronal alignment: main Cobb angle; preoperative C7-CSVL; amount of lateral listhesis; L4, L5, and sacral coronal tilt angles; coronal vertebral deformity angles; and coronal spine rigidity. Regarding risk factors for postoperative CM, patient characteristics, preoperative sagittal parameters, and coronal parameters did not significantly differ between the 2 groups, except for preoperative C7-CSVL (p = 0.016). Multivariate logistic regression analysis revealed that preoperative C7-CSVL (+1 cm; OR 1.23, 95% CI 1.05-1.50; p = 0.007) was a significant predictor of postoperative CM. Receiver operating characteristic curve analysis demonstrated that the cutoff value for preoperative C7-CSVL was +0.3 cm, the sensitivity was 85.7%, the specificity was 60.6%, and the area under the curve was 0.70. In corrective fusion surgery for DLKS in which multilevel LLIF was used, the occurrence of postoperative CM was associated with preoperative C7-CSVL. According to the C7-CSVL, which was evaluated by defining the convex side of the CSVL as positive numerical values and the concave side as negative numerical values, the CM group had a significantly higher value of preoperative C7-CSVL than did the non-CM group. Alternative corrective fusion methods, other than multiple LLIFs, may be considered in DLKS cases with a C7-CSVL of +0.3 cm or greater.

Short-segment percutaneous fusion versus open posterior fusion with screw in the fractured vertebra for thoracolumbar junction burst vertebral fracture treatment.

The treatment options for thoracolumbar junction burst fractures remain a topic of controversy. Short-segment percutaneous fixation (SSPF) and short-segment open fixation including the fractured level (SSOFIFL) are both viable procedures for managing these fractures. At present, there is a lack of evidence in the literature demonstrating the absolute superiority of one treatment over the other. This study aimed to compare these two surgical strategies with a focus on radiological and clinical outcomes. This retrospective case-control multicenter analysis involved patients with A3 and A4 vertebral fractures at the thoracolumbar junction (T11-L2) who underwent surgical treatment with either SSPF or SSOFIFL in the participating centers. Clinical outcomes were measured using the Oswestry Disability Index and visual analogue scale (VAS) both pre- and postoperatively. Radiological outcomes included kyphotic deformity (KD), anterior vertebral body height (AVBH), segmental kyphosis, and sagittal alignment parameters. A total of 156 patients were enrolled in the study, with 81 patients in Group A (SSPF) and 75 patients in Group B (SSOFIFL). Group B demonstrated better correction of KD (Group B: 3.4 ± 2.7° vs. Group A: 8.3 ± 3.2°, P = 0.003), AVBH, and sagittal alignment. A minor loss of correction was observed in Group B with respect to Group A (0.9 ± 1.7° vs 4.3° ± 2.1°, P = 0.043). Blood losses were lower in Group A (78 ± 15 min vs. 118 ± 23 min, P = 0.021) as well as during surgery (121.3 ± 34 mL vs. 210.2 ± 52 mL, P = 0.031), but the post-operative hemoglobin levels were comparable between the two groups. SSOFIFL appears to show a major amount of KD correction and prevent loss of correction. This technique should be the preferred choice whenever possible. However, SSPF can be considered a valid alternative for damage control in polytrauma patients and fractures with low KD.

Diagnosis and treatment of adult spinal deformity

Background: The diagnosis rate of adult spinal deformity (ASD) is increasing with increased life expectancy and the prevalence of degenerative spinal diseases. The prevalence of ASD in adults aged &gt;60 years has been reported to be up to 68%. ASD has significant impact on the pain, disability, and mental health. Therefore, it is necessary to establish an effective surgical plan by accumulating modern knowledge on ASD, developing surgical techniques, and improving pre- and post-operative care so as to achieve optimal surgical outcomes.Current Concepts: ASD results from coronal and sagittal malalignments caused by degenerative diseases or iatrogenic factors. Recently, the significance of sagittal alignment correction has been emphasized, and the SRSSchwab classification of ASD is generally accepted. Individualized correction goals can be set through sufficient preoperative evaluations and imaging studies, and appropriate coronal and sagittal alignment correction can be achieved through intraoperative positioning of patient, anterior and posterior approach spine surgery, screw fixation, and osteotomies.Discussion and Conclusion: It is necessary to establish an optimal correction target and select the appropriate surgical approach for each patient with ASD, so as to improve patients’ quality of life. Surgical interventions for ASD can be safely completed by adequately comprehending and anticipating perioperative complications.

Unilateral Minimally Invasive Across-Midline Vertebral Column Resection Partially Corrects Thoracolumbar Kyphosis – A Case Series

The goal of this study was to describe the indirect and partial correction of spine kyphotic deformities (secondary to various pathologies) achieved by minimally invasive posterolateral extracavitary approach (MIS-PLECA) for corpectomy. The authors retrospectively reviewed a consecutive case series of 12 patients undergoing MIS PLECA in a single institution. Perioperative data were collected and follow-up CTs and radiographs were reviewed to assess for interbody arthrodesis. The mean age was 60.7 ± 20.8 years (58.4% males). The etiologies of deformity included pathological fracture (41.6%), acute trauma (30%), and infection. An expandable cage was used in 66.7% of patients for anterior reconstruction. The mean total EBL was 764.1 ± 332.9 ml. The mean operative time was 413.3 ± 98.8 min. The average length of hospital stay was 5.8 ± 2.5 days. A consistent degree of focal correction of sagittal alignment was seen in all patients with a mean correction of sagittal angle of 7.4 ± 4.3 degrees (P<.0001). The mean duration of rehabilitation was 8.5 ± 6.7 days. All patients remained neurologically stable at the last follow-up with a mean follow-up period of 20.1 ± 12.8 months. Successful fusion was achieved in 91.7% at the last follow-up. MIS PLECA for corpectomy appears to be a feasible, safe, and effective MIS technique for select patients, particularly those who cannot tolerate the traditional open approach. Additionally, a focal sagittal deformity correction can be achieved using MIS corpectomy.

MINIMALLY INVASIVE SPINE SURGERY FOR POST-TRAUMATIC KYPHOSIS: A SYSTEMIC LITERATURE REVIEW AND RETROSPECTIVE CASE ANALYSIS

Study Design: Retrospective case analysis and systematic literature review. Objective: To comprehensively review minimally invasive surgery (MIS) for post-traumatic kyphosis. Methods: A systematic PubMed search was conducted for MIS and kyphotic deformities were published between 2012 and 2022. Sixteen patients between 2017 and 2021 met the criteria. Demographic data, surgical characteristics, and full-length radiographic parameters were collected pre- and post-operatively, and at final follow-up. Results: Twenty-three articles were included. The mean age was 67 years, and the mean follow-up was 17 months. The mean operative time was 331 min and blood loss was 252 ml. Pre-operative radiographic outcomes were as follows: Lumbar lordosis (LL), 16.84± 26.40[Formula: see text]; pelvic incidence (PI), 48.95± 14.34[Formula: see text]; PI-LL mismatch, 32.11± 31.92[Formula: see text]; pelvic tilt (PT), 32.74± 10.41[Formula: see text]; and sagittal vertical axis (SVA), 95.33± 59.62 mm. At the final follow-up, LL was 19.98± 16.16[Formula: see text] ([Formula: see text] = 0.51229), PI was 50.82± 10.19[Formula: see text] ([Formula: see text] = 0.61438), PI-LL mismatch was 30.84± 17.18[Formula: see text] ([Formula: see text] = 0.74696), PT was 27.14± 10.28[Formula: see text] ([Formula: see text] = 0.00386), and SVA was 49.73± 25.51 mm ( [Formula: see text] = 0.00465). The mean ODI and VAS scores for back pain at baseline and at 96 months follow-up were 33.2–19.7 and 8.4–2.5, respectively. Conclusion: Age-adjusted MIS provides correction of sagittal alignment for posttraumatic kyphosis that satisfies patient demand.

Crossing the cervicothoracic junction: an evaluation of radiographic alignment, functional outcomes, and patient-reported outcomes.

There is currently no consensus regarding the appropriate lower instrumented vertebra (LIV) for multilevel posterior cervical fusion (PCF) constructs between C7 and crossing the cervicothoracic junction (CTJ). The goal of the present study was to compare postoperative sagittal alignment and functional outcomes among adult patients presenting with cervical myelopathy undergoing multilevel PCF terminating at C7 versus spanning the CTJ. A single-institution retrospective analysis (January 2017-December 2018) was performed of patients undergoing multilevel PCF for cervical myelopathy that involved the C6-7 vertebrae. Pre- and postoperative cervical spine radiographs were analyzed for cervical lordosis, cervical sagittal vertical axis (cSVA), and first thoracic (T1) vertebral slope (T1S) in two randomized independent trials. Modified Japanese Orthopaedic Association (mJOA) and Patient-Reported Outcomes Measurement Information System (PROMIS) scores were used to compare functional and patient-reported outcomes at the 12-month postoperative follow-up. Sixty-six consecutive patients undergoing PCF and 53 age-matched controls were included in the study. There were 36 patients in the C7 LIV cohort and 30 patients in the LIV spanning the CTJ cohort. Despite significant correction, patients undergoing fusion remained less lordotic than asymptomatic controls, with a C2-7 Cobb angle of 17.7° versus 25.5° (p < 0.001) and a T1S of 25.6° versus 36.3° (p < 0.001). The CTJ cohort had superior alignment corrections in all radiographic parameters at the 12-month postoperative follow-up compared with the C7 cohort: increase in T1S (ΔT1S 14.1° vs 2.0°, p < 0.001), increase in C2-7 lordosis (ΔC2-7 lordosis 11.7° vs 1.5°, p < 0.001), and decrease in cSVA (ΔcSVA 8.9 vs 5.0 mm, p < 0.001). There were no differences in the mJOA motor and sensory scores between cohorts pre- and postoperatively. The C7 cohort reported significantly better PROMIS scores at 6 months (22.0 ± 3.2 vs 11.5 ± 0.5, p = 0.04) and 12 months (27.0 ± 5.2 vs 13.5 ± 0.9, p = 0.01) postoperatively. Crossing the CTJ may provide a greater cervical sagittal alignment correction in multilevel PCF surgeries. However, the improved alignment may not be associated with improved functional outcomes as measured by the mJOA scale. A new finding is that crossing the CTJ may be associated with worse patient-reported outcomes at 6 and 12 months of postoperative follow-up as measured by the PROMIS, which should be considered in surgical decision-making. Future prospective studies evaluating long-term radiographic, patient-reported, and functional outcomes are warranted.

Does total knee arthroplasty affect pelvic movements? A prospective comparative study.

Pathology in any segment of the spine-pelvis-lower extremity may impair the global postural balance, leading to compensatory alterations in other parts. The aim of this study was to compare the pelvic movements of patients suffering from knee osteoarthritis with patients who underwent total knee arthroplasty and healthy controls. This study was performed at the Department of Orthopedics and Traumatology Clinic of a Cankiri State Hospital between April 2021 and February 2022. This study included 84 participants. Of them, 31 patients who underwent total knee arthroplasty between 2018 and 2020 years were selected as the total knee arthroplasty group, while 28 patients with knee osteoarthritis were selected as the knee osteoarthritis group. In the control group, there were 25 healthy individuals. Exclusion criteria from the study included any kind of neurological disease, an inability to walk a distance of 100 m unassisted, or a history of surgery to the lower limb. Pelvic movements (i.e., tilt, rotation, and obliquity) and gait parameters (i.e., "gait velocity," "cadence," and "stride length") were assessed using a wireless tri-axial accelerometer. Total knee arthroplasty and control groups had decreased minimum anterior tilt of the pelvis, decreased maximum anterior tilt, and decreased oblique range of the pelvis compared with the knee osteoarthritis group. In comparison with the control group, gait velocity and length of stride during gait were remarkably lower in both knee osteoarthritis and total knee arthroplasty groups. In this study, total knee arthroplasty was found to affect pelvic movements. It was thought that total knee arthroplasty changed these variables, probably owing to the frontal and sagittal plane alignment correction through surgery.

69. Outcomes after coronal alignment correction in patients with trunk shift toward the curve convexity

<h3>BACKGROUND CONTEXT</h3> Patients with coronal malalignment with trunk shift toward the convexity of the main coronal curve, and oblique takeoff at the lumbosacral junction, present a unique problem for deformity correction. <h3>PURPOSE</h3> To evaluate fractional curve and coronal malalignment correction, and rate of complications and unplanned revision in Bao Type C patients, compared to Bao Type A and B patients. <h3>STUDY DESIGN/SETTING</h3> Retrospective review of prospectively collected singlecenter database. <h3>PATIENT SAMPLE</h3> This study included 1039 ASD patients (age: 46 ± 23 y; mFI: .4 ± .7; levels fused: 10.0 ± 4.2). <h3>OUTCOME MEASURES</h3> Outcomes evaluated were coronal alignment and fractional curve correction, and rates of revision surgery at two-year follow-up. <h3>METHODS</h3> A total of 1039 adult spinal deformity patients (age: 46 ± 23 y; mFI: .4 ± .7; levels fused: 10.0 ± 4.2), with minimum five levels fused for thoracolumbar scoliosis were divided into three groups, as proposed by Bao et al: type A: CSVL 3cm and C7 plumb shifted to scoliosis' concavity (n=126); type C: CSVL > 3cm and C7 plumb shifted to scoliosis' convexity (n=30). Outcomes evaluated were coronal alignment and fractional curve correction, and rates of revision surgery at two-year follow-up. <h3>RESULTS</h3> Type C patients more often had fractional curves, and the preoperative magnitude was significantly greater (15.7° Type C, 12.9° Type B, 9.6° Type A, p <0.0001). Of the Type C patients, 50% had pedicle subtraction osteotomy performed, compared with 13.4% Type B, and 13.4% Type A (p <0.0001). Postoperatively, Type C patients continued to have persistently greater fractional curves (7.4° Type C, 6.7° Type B, 5.6° Type A, p=0.026), and worse coronal malalignment (37.8 mm Type C, 34.1 mm Type B, 17.0 mm type A, p<0.0001), though equivalent results with regards to improvement in sagittal alignment, lumbar lordosis, pelvic tilt, and Cobb angle of the major curve. There rate of neurologic complications was higher in the Type C patients, specifically related to TLIF or PSO procedure performed. ALIF procedure in the Type C patients did not confer significant improvement in fractional curve correction, coronal or sagittal alignment correction, or greater lumbar lordosis, compared with TLIF procedure in these patients. There was no difference in the rate of 90-day unplanned readmission or reoperation between the groups. There was no difference in rates of rod fracture or pseudarthrosis at the interbody or PSO site in Type C patients, compared with Type A and B patients. There was no difference in rates or rod fracture, pseudarthrosis, adjacent segment disease, proximal junctional kyphosis, or reoperation for recurrent or persistent malalignment between the two groups at two-year follow-up. <h3>CONCLUSIONS</h3> At two-year follow-up, Type C coronal malalignment patients continue to have worse coronal deformity and fractional curve magnitude compared with Type A and B patients, with no difference, however, in long-term rod fracture, pseudarthrosis or revision surgery rates. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

The 3-triangle method preserves the posterior tibial slope during high tibial valgus osteotomy: first preliminary data using a mathematical model

PurposeDespite much improved preoperative planning techniques accurate intraoperative assessment of the high tibial valgus osteotomy (HTO) remains challenging and often results in coronal over- and under-corrections as well as unintended changes of the posterior tibial slope. Noyes et al. reported a novel method for accurate intraoperative coronal and sagittal alignment correction based on a three-dimensional mathematical model. This is the first study examining preliminary data via the proposed Noyes approach for accurate intraoperative coronal and sagittal alignment correction during HTO.MethodsFrom 2016 to 2020 a total of 24 patients (27 knees) underwent HTO applying the proposed Noyes method (Noyes-Group). Radiographic data was analyzed retrospectively and matched to patients that underwent HTO using the conventional method, i.e., gradual medial opening using a bone spreader under fluoroscopic control (Conventional-Group). All operative procedures were performed by an experienced surgeon at a single orthopaedic university center.ResultsFrom the preoperative to the postoperative visit no statistically significant changes of the posterior tibial slope were noted in the Noyes-Group compared to a significant increase in the Conventional-Group (p = 0.01). Regarding the axial alignment no significant differences between both groups were observed pre- and postoperatively. The number of over- and under-corrections did not differ significantly between both groups. Linear regression analysis showed a significant correlation of the postoperative medial proximal tibial angle (MPTA) with the position of the weightbearing line on the tibial plateau.ConclusionThe 3-triangle method by Noyes seems to be a promising approach for preservation of the posterior tibial slope during HTO.

Assessment of clinical, imaging, surgical risk factors for subsequent fracture following vertebral augmentation in osteoporotic patients.

Currently, the risk factors for subsequent fracture following vertebral augmentation remain incomplete and controversial. To provide clinicians with accurate information for developing a preventive strategy, we carried out a comprehensive evaluation of previously controversial and unexplored risk factors. We retrospectively reviewed patients with osteoporotic vertebral compression fracture in lumbar spine who received vertebral augmentation between January 2019 and December 2020. Based on whether refracture occurred, patients were assigned to refracture and non-refracture group. The clinical characteristics, imaging parameters (severity of vertebral compression, spinal sagittal alignment, degeneration of paraspinal muscles), and surgical indicators (cement distribution and leakage, correction of spinal sagittal alignment) were collected and analyzed. There were 128 patients and 16 patients in non-refracture and refracture group. The incidence of previous fracture, multiple fractures, and cement leakage were notably higher, relative cross-sectional area of psoas (r-CSAPS) was significantly smaller, CSA ratio, fatty infiltration of erector spinae plus multifidus (FIES+MF), FIPS, postoperative lumbar lordosis (post-LL), correction of body angel (BA), and LL were significantly greater in refracture group. Binary logistic regression analysis revealed previous fracture, cement leakage, post-LL, and correction of BA were independent risk factors. According to the ROC curve, correction of BA showed the highest prediction accuracy, and the critical value was 3.45°. The occurrence of subsequent fracture might be the consequence of multiple factors. Previous fracture, cement leakage, post-LL, and correction of BA were identified as independent risk factors. Furthermore, the correction of BA should not exceed 3.45°, especially in patients with risk factors.

Patients With Preoperative Cervical Deformity Experience Similar Clinical Outcomes to Those Without Deformity Following 1-3 Level Anterior Cervical Decompression and Fusion.

Retrospective cohort study. The aim was to compare the outcomes of patients with incompletely corrected cervical deformity against those without deformity following short-segment anterior cervical decompression and fusion for clinically significant radiculopathy or myelopathy. Cervical deformity has increasingly been recognized as a driver of disability and has been linked to worse patient-reported outcomes measures (PROMs) after surgery. Patients 18 years or above who underwent 1-3 level anterior cervical decompression and fusion to address radiculopathy and/or myelopathy at a single institution between 2014 and 2018 with at least 1 year of PROMs were reviewed. Patients were categorized based on cervical deformity into 2 groups: sagittal vertebral axis (cSVA) ≥40 mm as the deformity group, and cSVA <40 mm as the nondeformity group. Patient demographics, surgical parameters, preoperative and postoperative radiographs, and minimum 1-year PROMs were compared. Of the 230 patients, 191 (83%) were in the nondeformity group and 39 (17%) in the deformity group. Patients with deformity were more likely to be male (69.2% vs. 40.3%, P<0.001) and have a greater body mass index (32.8 vs. 29.7, P=0.028). The deformity group had significantly greater postoperative cSVA (44.2 vs. 25.1 mm, P<0.001) but also had significantly greater ∆cSVA (-4.87 vs. 0.25 mm, P=0.007) than the nondeformity group. Both groups had significant improvements in visual analog scale arm, visual analog scale neck, Short-Form 12 Physical Component Score, and neck disability index (NDI) (P<0.001). However, the deformity group experienced significantly greater ∆NDI and ∆mental component score (MCS)-12 scores (-19.45 vs. -11.11, P=0.027 and 7.68 vs. 1.32, P=0.009). Patients with preoperative cervical sagittal deformity experienced relatively greater improvements in NDI and MCS-12 scores than those without preoperative deformity. These results suggest that complete correction of sagittal alignment is not required for patients to achieve significant clinical improvement. III.

Impact of Preoperative Total Knee Arthroplasty on Radiological and Clinical Outcomes of Spinal Fusion for Concurrent Knee Osteoarthritis and Degenerative Lumbar Spinal Diseases.

Concurrent knee osteoarthritis (KOA) and degenerative lumbar spinal disease (LSD) has increased, but the total knee arthroplasty (TKA) effect on degenerative LSD remains unclear. The aim of this study was to retrospectively analyze to compare radiological and clinical outcomes between spinal fusion only and preoperative TKA with spinal fusion for the patients with concurrent KOA and degenerative LSD. A total of 72 patients with concurrent KOA and degenerative LSDs who underwent spinal fusion at less than three levels were divided in two groups: non-TKA group (n = 50) and preoperative TKA group (n = 22). Preoperative lumbar lordosis (LL) was significantly lower in the preoperative TKA group than the non-TKA group (p < 0.05). Significantly higher preoperative pelvic incidence (PI), PI/LL mismatch, and pelvic tilt (PT) occurred in preoperative TKA group than non-TKA group (all p < 0.05). There was significant improvement of postoperative Oswestry Disability Index and leg Visual Analog Scale in the preoperative TKA group (all p < 0.01). Preoperative TKA could be a benefit for in proper correction of sagittal spinopelvic alignment by spinal fusion. Therefore, preoperative TKA could be considered a preceding surgical option for patients with severe sagittal spinopelvic parameters in concurrent KOA and degenerative LSD.

Lumbar Level Significantly Influences Postoperative Global Sagittal Balance Following Pedicle Subtraction Osteotomy.

Retrospective cohort study. The current evidence regarding how level of lumbar pedicle subtraction osteotomy (PSO) influences correction of sagittal alignment is limited. This study sought to investigate the relationship of lumbar level and segmental angular change (SAC) of PSO with the magnitude of global sagittal alignment correction. This study retrospectively evaluated 53 consecutive patients with adult spinal deformity who underwent lumbar PSO at a single institution. Radiographs were evaluated to quantify the effect of PSO on lumbar lordosis (LL), thoracic kyphosis (TK), sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), T1-spinopelvic inclination (T1SPI), T1-pelvic alignment (TPA), and sagittal vertical axis (SVA). Significant correlations were found between PSO SAC and the postoperative increase in LL (r = 0.316, P = .021) and PT (r = 0.352, P = .010), and a decrease in TPA (r = -0.324, P = .018). PSO level significantly correlated with change in T1SPI (r = -0.305, P = .026) and SVA (r = -0.406, P = .002), with more caudal PSO corresponding to a greater correction in sagittal balance. On multivariate analysis, more caudal PSO level independently predicted a greater reduction in T1SPI (β = -3.138, P = .009) and SVA (β = -29.030, P = .001), while larger PSO SAC (β = -0.375, P = .045) and a greater number of fusion levels (β = -1.427, P = .036) predicted a greater reduction in TPA. This study identified a gain of approximately 3 degrees and 3 cm of correction for each level of PSO more caudal to L1. Additionally, a larger PSO SAC predicted greater improvement in TPA. While further investigation of these relationships is warranted, these findings may help guide preoperative PSO level selection.

Review Article On Recent Trends in Surgical Techniques for High-grade Spondylolisthesis

Introduction: High-grade spondylolisthesis is defined as cases with more than 50% displacement and spondylolisthesis with Meyerding grade III and higher. The surgical management of high-grade spondylolisthesis is highly controversial. Many surgical methods have been reported like posterior in situ fusion, instrumented posterior fusion with or without reduction, combined anterior and posterior procedures, spondylectomy with reduction of L4 to the sacrum (for spondyloptosis), posterior interbody fusion with trans-sacral fixation. Minimally invasive transforaminal lumbar interbody fusion for high-grade spondylolisthesis has also been recently mentioned in literature. This study aimed to review the recent literature which has described the surgical outcomes associated with various surgical techniques used for high-grade spondylolisthesis Materials and Methods: Recent articles were searched on search engines such as PubMed, Google Scholar with the use of Keywords like ‘High-grade Spondylolisthesis’, ‘Surgical Techniques’ ‘complications’. Discussion: The surgical management of high-grade spondylolisthesis is an area of significant controversies. The literature is replete with regards to need for reduction, need for decompression, levels of fusion, the nature of instrumentation, surgical approaches including open, minimally invasive, and “mini-open” procedures, as well as various techniques for reduction of the slip and fusion strategy. The three basic options of high-grade spondylolisthesis include in-situ fusion, partial reduction and fusion, and complete reduction. Conclusion: Various techniques have been described for high-grade spondylolisthesis. Spine Deformity Study Group (SDSG) classification gives guidelines about balanced and unbalanced pelvis and advising reduction and fusion in case of unbalanced pelvis for correction of biomechanical and global sagittal alignment. Each of the surgical techniques has their own advantages and disadvantages. Although individual a

Expandable Technology Improves Clinical and Radiographic Outcomes of Minimally Invasive Lateral Lumbar Interbody Fusion for Degenerative Disc Disease.

Static interbody spacers are standard of care for minimally invasive lateral lumbar interbody fusion (MIS LLIF). However, placement of large static interbody spacers typically requires multiple trialing, endplate preparation, and forceful impaction. A lateral expandable interbody spacer with adjustable lordosis can be inserted at a reduced height, to optimize the endplate-to-endplate fit. This study describes radiographic and clinical outcomes in patients treated using lateral titanium expandable interbody spacers with adjustable lordosis using MIS LLIF. This is a single-surgeon, retrospective, institutional review board-exempt chart review of 24 consecutive patients who underwent MIS LLIF at 1-2 contiguous level(s) using expandable spacers with adjustable lordosis. Radiographic and clinical functional outcomes were collected and compared at preoperative and postoperative time points up to 24 months. Parametric and nonparametric tests were used when appropriate. Statistical results were significant if P < .05. Twenty-four consecutive patients were evaluated with an average age of 57.8 ± 12.6 years; 45.8% were female. Visual analog scale for back pain improved by 7.3 ± 1.0 points, whereas Oswestry Disability Index scores improved by a mean of 67.5 ± 11.3 points at 24 months (P < .001). Lumbar lordosis improved by a mean of 6.3 ± 10.1° at 24 months (P < .001). There were 29 spinal levels, with 41.4% at L4-5 and 34.5% at L3-4. Anterior, middle, and posterior disc height significantly increased at 24 months by means of 4.5 ± 2.9 mm, 4.0 ± 2.8 mm, and 2.6 ± 1.9 mm, respectively (P < .001). Neuroforaminal height significantly improved by 3.3 ± 3.9 mm at 24 months (P < .001). Segmental lordosis improved by 3.6 ± 3.0° at 24 months. This study showed significant positive clinical and radiographic outcomes for patients who underwent MIS LLIF using expandable interbody spacers with adjustable lordosis. Correction of sagittal alignment was achieved and maintained up to 2-year follow-up. The use of expandable spacers with adjustable lordosis was shown to be safe and effective in this cohort. 3.