Facet Joint Bridging in Adolescent-onset Adult Idiopathic Scoliosis with Thoracolumbar/Lumbar Curves.

OBJECTIVE: This study aims to comprehend the natural history of Adolescent idiopathic scoliosis (AIS) patients and determine risk factors for facet joint bridging in adolescent-onset adult idiopathic scoliosis with thoracolumbar/lumbar (TL/L) curves. METHODS: We included 50 patients with residual AIS with TL/L curves (3 males, 47 females; age 41.5±17.3 years, TL/L Cobb angle 59.4±11.8°). They were >20 years old and diagnosed with AIS during their adolescence. Radiographic parameters were measured, and facet joint bridging was defined from axial computed tomography (CT) images. RESULTS: The sagittal vertical axis (SVA) significantly increased with age (r=0.71, p<0.01). Coronal Cobb angle of the TL/L curve, L4 tilt, C7 translation, lumbar lordosis (LL), Pelvic incidence (PI) -LL, pelvic tilt (PT), and thoracolumbar kyphosis (TLK) were also correlated to age (p<0.05). There were significant differences in age, SVA, PI-LL, vertebral bridging, facet tropism, and apical vertebral rotation (AVR) between the facet joint bridging group (n=10) and the non-facet joint bridging group (n=40). In the multivariate logistic regression analysis, SVA, vertebral bridging, and AVR emerged as notable risk determinants for facet joint bridging. The threshold for facet joint bridging based on SVA was 2.1 cm (area under the curve [AUC]: 0.801; sensitivity = 90%, specificity = 65%). CONCLUSION: This research revealed that large SVA, the presence of vertebral bridging, and large AVR are associated with facet joint bridging in adolescent-onset adult idiopathic scoliosis patients with TL/L curves. The cut-off value for facet joint bridging based on SVA was 2.1cm.

Factors influencing the achievement of early surgery in proximal femoral fractures under a Japanese incentive policy.

BACKGROUND: Proximal femoral fractures in geriatric patients are a major challenge in orthopedics, often leading to major functional impairment. Early surgical intervention is crucial for improving patient recovery and overall health outcomes. Thus, Japan's Ministry of Health, Labour and Welfare initiated a reimbursement policy in April 2022 to encourage early surgery for these fractures in patients aged ≥75 years. This study investigated the impact of this policy on early surgery rates in Japan and identified factors influencing the timing of surgical interventions. METHODS: We retrospectively analyzed the data of patients who underwent surgery for proximal femoral fractures at our institution between April 2022 and March 2023. Patients were categorized into two groups based on the timing of surgery relative to the injury: ≤48 h and >48 h. Demographic and clinical data, including age, sex, fracture type, and various health- and admission-related factors, were assessed. RESULTS: Of the 192 patients, 152 were included in the study. Among them, 38% underwent early surgery (≤48 h), and 15% of the patients arrived more than 48 h post-injury. Significant differences were found in admission routes and residence types between the groups. The ≤48 h group had shorter intervals from injury to admission and surgery than the >48 h group. Factors such as the admission process, day of the week, and C-reactive protein levels significantly influenced the timing of surgery. CONCLUSIONS: After introducing incentives for early surgery in Japan, 38% of patients with proximal femoral fractures underwent surgery within 48 h of injury. Factors contributing to patients not receiving early surgery included transport from another hospital, weekend hospitalization, and elevated CRP levels. These findings suggest that achieving surgery within 48 h of injury is challenging through hospital efforts alone, and the time criteria might be more appropriate if changed to "admission to surgery."

A novel simultaneous three-dimensional volumetric morphological imaging and T2-mapping method, multi-interleaved X-prepared turbo-spin echo with intuitive relaxometry provides more accurate quantification of cervical spinal nerves.

PURPOSE: MIXTURE is a simultaneous morphological and quantitative imaging sequence developed by Philips that provides high-resolution T2 maps from the imaged series. We aimed to compare the T2 maps of MIXTURE and SHINKEI-Quant (S-Q) in the cervical spine and to examine their usefulness in the functional diagnosis of cervical radiculopathy. METHODS: Seven healthy male volunteers (mean age: 31 ± 8.0 years) and one patient with cervical disc herniation (44 years old, male) underwent cervical spine magnetic resonance imaging (MRI), and T2-mapping of each was performed simultaneously using MIXTURE and S-Q in consecutive sequences in one imaging session. The standard deviation (SD) of the T2 relaxation times and T2 relaxation times of the bilateral C6 and C7 dorsal root ganglia (DRG) and C5/6 level cervical cord on the same slice in the 3D T2-map of the cervical spine coronal section were measured and compared between MIXTURE and S-Q. RESULTS: T2 relaxation times were significantly shorter in MIXTURE than in S-Q for all C6, C7 DRG, and C5/6 spinal cord measurements. The SD values of the T2 relaxation times were significantly lower for MIXTURE in the C5/6 spinal cord and C7 DRG. In cervical disc herniation, MRI showed multiple intervertebral compression lesions with spinal canal stenosis at C5/6 and disc herniation at C6/7. CONCLUSION: MIXTURE is useful for preoperative functional diagnosis. T2-mapping using MIXTURE can quantify cervical nerve roots more accurately than the S-Q method and is expected to be clinically applicable to cervical radiculopathy.

Measurement of Postoperative Apical Vertebral Rotation Using Radiographic Images in Adolescent Idiopathic Scoliosis-Quantitative Evaluation Using Inverse Trigonometric Functions.

Introduction: Conventional methods for analyzing vertebral rotation are limited to postoperative patients who underwent posterior fusion. A previous methodology calculated vertebral rotation using inverse trigonometric functions based on the length of the pedicle screw (PS). Accordingly, this study evaluates rotational deformity in patients with postoperative adolescent idiopathic scoliosis (AIS) using inverse trigonometric functions. Methods: This retrospective single-center study includes patients with AIS who underwent posterior fusion surgery. Postoperative radiography and computed tomography (CT) scans were retrospectively evaluated. The magnification ratio was calculated using the rod diameter (δ=lateral/frontal rod diameter), and the visible screw lengths were measured using radiographs. The rotation angle was calculated using the apex of the main curve and the lower instrumented vertebra (LIV) (rotation angle=tan-1 (lateral PS length/(δ×frontal PS length))) immediately following the surgery as well as two and five years postoperatively. The correlation between the direct CT measurement and postoperative rotation angle progression was investigated. The crankshaft phenomenon (CSP) and distal adding-on (DAO) were evaluated as postoperative deformities. CSP was defined as a 5° increase in rotation angle. Results: Seventy-eight patients (age: 15.3±2.0 years, eight boys and seventy girls) were included. The rotation angle was strongly correlated with CT rotation measurements (r=0.87). The mean rotation angle at the apex and LIV did not change within five years postoperatively (mean: 0.5±3.6° and 0.4±3.4°, respectively). CSP and DAO were observed in 6.4% and 3.8% of patients, respectively. Conclusions: The inverse trigonometric method is useful to quantitatively evaluate the postoperative rotation angle and identify CSP.

The Optimal Patient Position on the Surgical Table for Lateral Lumbar Interbody Fusion in Adult Spinal Deformity Using Three-Dimensional Computed Tomography: A Retrospective Study.

Introduction: Lateral lumbar interbody fusion (LLIF) techniques have been extensively used in adult spinal deformity surgery. Preoperative knowledge of the optimal position of the patient on the surgical table is essential for a safe procedure. Therefore, this study aims to determine the optimal angle for positioning the patient on the surgical table during LLIF using three-dimensional computed tomography (3DCT). Methods: Data from 59 patients (2 males, 57 females, mean age 66.3±8.6 years) with adult spinal deformities treated by performing corrective spinal surgery were included in this observational retrospective study. Simulated fluoroscopic images were obtained using 3DCT images rotated from the reference position with the spinous process of S1 as the midline to the position with the spinous process in the center of the bilateral pedicle of T12-L5. The rotation angle of each vertebra was measured and defined as the optimal rotation angle (ORA). The angle that bisected the angle between the maximum and minimum ORA was defined as the optimal mean angle of the maximum and minimum ORA (OMA) and considered the optimal angle for the patient's position on the surgical table, as this position could minimize the rotation angle of the surgical table during surgery. A multiple regression analysis was performed to predict OMA. Results: Multiple regression analysis revealed the following equation: OMA=1.959+(0.238×lumbar coronal Cobb angle)+(-0.208×sagittal vertical axis). Conclusions: When the patient is placed on the surgical table by rotating them at the OMA, the rotation of the surgical table can be reduced, ensuring a safe and efficient surgical procedure.

Association of Spinal Corrective Surgery With Abdominal Aorta Length in Patients With Adult Spinal Deformity.

Introduction This research aimed to explore the relationship between spinal characteristics and the length of the abdominal aorta in adult spinal deformity (ASD) patients who underwent corrective spinal surgery. We hypothesized that adjusting spinal alignment might affect the abdominal aorta's length. Methods This study included thirteen patients with ASD (average age: 63.0 ± 8.9 years; four males and nine females) who received spinal correction surgery. We measured both pre-operative and post-operative spinal parameters, including thoracolumbar kyphosis (TLK), and calculated their differences (Δ). The length of the aorta (AoL) was determined using an automated process that measures the central luminal line from the celiac artery's bifurcation to the inferior mesenteric artery. This measurement was made using contrast-enhanced computed tomography for three-dimensional aortic reconstruction. We compared the pre-operative and post-operative AoLs and their differences (Δ). The study examined the correlation between changes in spinal parameters and changes in AoL. Results Post-operatively, there was an increase in aortic length (ΔAoL: 4.2 ± 4.9 mm). There was a negative correlation between the change in TLK and the change in AoL (R2 = 0.45, p = 0.012, ß = -0.21). No significant correlations were found with other spinal parameters. Conclusions The abdominal aorta can elongate by 4.8% after spinal corrective surgery in patients with ASD. The degree of elongation of the abdominal aorta is associated with spinal alignment correction.

Bone union-promoting effect of romosozumab in an ovariectomized rat posterolateral lumbar fusion model.

Spinal fixation surgery has been increasingly performed in patients with osteoporosis. Romosozumab, a drug that was introduced in Japan recently, is known to possibly promote bone healing. However, few studies have reported the therapeutic effects of romosozumab in clinical practice in Japan. Therefore, here, we investigated the effects of romosozumab dosage on bone fusion promotion using an ovariectomized rat spinal fusion model. Eight-week-old female Sprague-Dawley rats were matched by body weight and divided into three groups: 1.0 romosozumab (R) group (Evenity®, 25 mg/kg), 1/10R group (Evenity®, 2.5 mg/kg), and control (C) group (saline). Subcutaneous injections were administered twice a week for 8 weeks postoperatively. Computed tomography scans were performed every 2 weeks from the time of surgery till 8 weeks postoperatively. The mean fusion rates in terms of volume were significantly higher in the R groups [1/10R, 1.0R] than in the C group from 4 weeks postoperatively. The rate of increase was significantly higher in the 1.0R group from 4 weeks postoperatively and in the 1/10R group from 6 weeks postoperatively, than in the C group. The proportion of trabecular bone area was approximately 1.5 times higher in the R groups than in the C group. No significant differences were observed between the R groups. Our results suggest that romosozumab stimulates bone growth at the graft site, and similar effects were achieved at 1/10 of the standard dosage.

Machine learning algorithms for predicting Cobb angle beyond 25 degrees in female adolescent idiopathic scoliosis patients.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To develop a machine learning (ML) model that predicts the progression of AIS using minimal radiographs and simple questionnaires during the first visit. SUMMARY OF BACKGROUND DATA: Several factors are associated with angle progression in patients with AIS. However, it is challenging to predict angular progression at the first visit. METHODS: Among female patients with AIS treated at a single institution from July 2011 to February 2023, 1119 cases were studied. Patient data, including demographic and radiographic data based on anterior-posterior and lateral whole-spine radiographs, were collected at the first and last visits. The last visit was defined differently based on treatment plans. For patients slated for surgery or bracing, the last visit occurred just before these interventions. For others, it was their final visit before turning 18 years. Angular progression was defined as a Cobb angle greater than 25 degrees for each of the proximal thoracic (PT), main thoracic (MT), and thoracolumbar/lumbar (TLL) curves at the last visit. ML algorithms were employed to develop individual binary classification models for each type of curve (PT, MT, and TLL) using PyCaret in Python. Multiple models were explored and analyzed, with the selection of optimal models based on the area under the curve (AUC) and Recall scores. Feature importance was evaluated to understand the contribution of each feature to the model predictions. RESULTS: For PT, MT, and TLL progression, the top-performing models exhibit AUC values of 0.94, 0.89, and 0.84, and achieve recall rates of 0.90, 0.85, and 0.81. The most significant factors predicting progression varied for each curve: initial Cobb angle for PT, presence of menarche for MT, and Risser grade for TLL. CONCLUSIONS: This study introduces an ML-based model using simple data at the first visit to precisely predict angle progression in female patients with AIS.

Short-Term Clinical and Radiographic Evaluation of Patients Treated With Expandable and Static Interbody Spacers Following Lumbar Lateral Interbody Fusion.

OBJECTIVE: The goal of this study was to evaluate, using computed tomography (CT) and magnetic resonance imaging (MRI), patients who underwent oblique lateral interbody fusion (OLIF) using either expandable or static interbody spacers. METHODS: Thirty-five patients with degenerative disc disease were surgically treated with one-level OLIF and were followed up for more than 6 months. The Static group consisted of 22 patients, and 13 patients were in the Expandable group. Intraoperative findings included operative time (min), blood loss (ml), and cage size. Low back pain, leg pain, and leg numbness were measured using the Japanese Orthopedic Association score, visual analogue score, and the Roland-Morris Disability Questionnaire. Radiologic evaluation using computed tomography (CT) and magnetic resonance imaging (MRI) allowed measurement of cage subsidence, cross-sectional area (CSA) of the dural sac, disc height, segmental lordosis, foraminal height, and foraminal CSA preoperatively and 6 months postoperatively. RESULTS: The Expandable group had significantly larger cage height and lordosis than the Static group (P < 0.05). The Expandable group also had greater dural sac area expansion and enlargement of the intervertebral foramen, as well as better correction of vertebral body slip (P < 0.05). Cage subsidence was significantly lower in the Expandable group (P < 0.05). JOA and VAS scores for leg numbness were significantly better in the Expandable group (P < 0.05). CONCLUSIONS: Compared with static spacers, expandable spacers significantly enlarged the dural sac area, corrected vertebral body slippage, expanded the intervertebral foramen, and achieved good indirect decompression while reducing cage subsidence, resulting in improvement in clinical symptoms.

Does vacuum phenomenon at non-fused discs affect the postoperative course after transforaminal lumbar interbody fusion in patients showing a positive value of difference in lumbar lordosis?

INTRODUCTION: Preoperative difference in lumbar lordosis (DiLL) was associated with surgical outcomes after single-level transforaminal lumbar interbody fusion (TLIF). Patients with DiLL>0 (DiLL (+)) tended to show worse clinical outcomes and postoperative greater restoration of lumbar lordosis (LL). However, some patients with DiLL (+) showed relatively good outcomes and no postoperative LL restration. This study aimed to elucidate whether the lumbar intervertebral disc vacuum phenomenon (VP) influences clinical course after single-level TLIF in patients with DiLL (+) and DiLL (-). METHODS: Patients with lumbar spinal stenosis and degenerative spondylolisthesis treated with single-level TLIF were included. Pre- and postoperative LL were measured, and postoperative LL improvement was calculated. Preoperative DiLL was calculated as preoperative supine LL minus standing LL. Severity of VP at the non-fused discs (SVP (non-FS)) was evaluated using preoperative reconstructed computed tomography imaging. Clinical outcomes were assessed using the Oswestry disability index, visual analogue scale (VAS; low back pain (LBP), lower-extremity pain, numbness, and the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire. Patients were stratified by the median preoperative SVP (non-FS) score into severe and mild VP groups in patients with DiLL (+) or DiLL (-), and their surgical outcomes were compared. RESULTS: Overall, 89 patients were included. In patients with DiLL (+) (n = 37), patients with severe VP showed worse clinical outcomes, particulary for LBP and DiLL (+) patients with mild VP showed greater LL improvement (6.5° ± 10.0°). In patients with DiLL(-) (n = 52), patients with severe VP showed worse clinical outcomes, particularly for LBP and no differences in preoperative, postoperative, and improvement of LL were observed between two groups. CONCLUSION: Patients with DiLL (+) and DiLL (-) showed different clinical courses depending on VP severity at the non-fused discs after single-level TLIF.

Analysis of the relationship between spinal alignment and retrocrural space area in adult spinal deformity surgery: Potential risk factors for acute celiac artery compression syndrome.

PURPOSE: This study was designed to reveal the association between spinal parameters and RCS area in patients with adult spinal deformities treated with spinal correction surgery. We hypothesized that reduction of the retrocrural space (RCS) area is related to thoracolumbar alignment, which may cause acute celiac artery compression syndrome (ACACS). METHODS: Eighty-nine patients (age: 68.4 ± 7.6 years; sex: 7 male/82 female) with ASD treated by spinal correction surgery were enrolled. Preoperative and postoperative spinal parameters were measured, and the differences between these parameters were calculated. Postoperative T12 translation was measured and RCS area was evaluated using reconstructed computed tomography. The change of RCS area after surgery was defined as ΔRCS. Patients were divided into increased and decreased RCS groups by the ΔRCS value, and spinal parameters were compared between groups. The correlation between spinal parameters and ΔRCS was calculated. RESULTS: The patients in the decreased RCS group had greater anterior T12 translation than those in the increased RCS group (p < 0.001). T12 translation was significantly correlated with ΔRCS (ß = -0.31, p = 0.017). There were no correlations between ΔRCS and other spinal parameters. CONCLUSION: Thoracolumbar alignment was associated with RCS area. Consistent with the hypothesis, overcorrection of the thoracolumbar junction was associated with reduced RCS area and might be one risk factor for ACACS.

Anatomical Analysis of the S1 Neural Foramen Using Three-Dimensional Computed Tomography Imaging: Insights for Effective S1 Nerve Root Block.

OBJECTIVE: The first sacral nerve root block (S1 NRB) is used to diagnose and treat lumbosacral and radicular pain. This study aims to clarify the anatomy of the S1 neural foramen using three-dimensional (3D) computed tomography (CT) images and to establish the optimal fluoroscopic angle, localize the S1 neural foramen on fluoroscopy, and determine the safe puncture depth for S1 NRB. METHODS: In this single-center cohort study, 200 patients with lumbar degenerative disease who underwent preoperative CT were enrolled. Four distinct studies were conducted using the CT data. Study 1 examined the correlation of the sacral slope angle and the supine and prone positions. Study 2 analyzed the tunnel view angle (TVA) using 3D reconstruction. Study 3 ascertained the location of the S1 neural foramen in fluoroscopy images. Study 4 investigated the safe depth for performing S1 NRB. RESULTS: The regression analysis in Study 1 revealed a correlation of the sacral slope angle and the supine and prone positions. Study 2 determined an optimal fluoroscopic TVA of approximately 30° for the S1 NRB. Study 3 found that the S1 neural foramen was located caudal to the L5 pedicle 1.7 ± 0.2 times the distance between the L4 and L5 pedicles. Study 4 revealed that the depths of the S1 neural foramen and root were 27.0 ± 2.1 mm and 16.5 ± 2.0 mm, respectively. CONCLUSIONS: Our study suggests an optimal fluoroscopic angle, a simple method to locate the S1 neural foramen on fluoroscopy, and an ideal puncture depth for a safe and effective S1 NRB.

Median Arcuate Ligament and Origin of the Celiac Artery Proximity Change in Patients after Surgery to Correct Adult Spinal Deformity: Potential Risk Factors for Acute Celiac Artery Compression Syndrome.

Introduction: This study aimed to determine whether the proximity of the median arcuate ligament (MAL) and the celiac artery (CA) changes in patients following surgery to correct adult spinal deformity (ASD). We hypothesized that the distance between the MAL and the CA shortens after corrective spinal surgery, which may cause acute celiac artery compression syndrome (ACACS). Methods: A total of 89 patients (68.4±7.6 years; 7 men/82 women) with ASD treated with spinal correction surgery were included in the present retrospective study. The level of the MAL, CA, and distance between the MAL and the CA (DMC) were determined via reconstructed computed tomography. MAL overlap was determined preoperatively and postoperatively. Results: The MAL and CA moved caudally following surgery. On average, after surgery, no changes in DMC were observed. We found preoperative MAL overlap in 32 (36%) patients, who also had postoperative MAL overlap. No patients showed any MAL overlap postoperatively. Conclusions: Contrary to our hypothesis, the distance between the MAL and the CA did not shorten, and emerging MAL overlap was not observed postoperatively.

Incidence and Potential Risk Factors of Superior Mesenteric Artery Syndrome After Spinal Corrective Surgery in Patients with Adult Spinal Deformity.

OBJECTIVE: This study aimed to determine the incidence and potential risk factors of superior mesenteric artery syndrome (SMAS) after corrective spinal surgery in patients with adult spinal deformity (ASD). METHODS: In total, 102 patients (67.6 ± 8.4 years; 8 male/94 female; body mass index (BMI); 22.4 ± 3.6 kg/m2) with ASD treated by spinal correction surgery were enrolled. Preoperative and postoperative spinal parameters, including thoracolumbar kyphosis (TLK: T10-L2) and upper lumbar lordosis (ULL: L1-L4) were measured. To evaluate the potential risk factors of SMAS, the angle and the distance between the superior mesenteric artery and aorta, the aortomesenteric angle (AMA) and aortomesenteric distance (AMD), were evaluated pre- and postoperatively. Based on the postoperative AMA, AMD, and abdominal symptoms, the patients were diagnosed with SMAS. Correlations between demographic data or spinal parameters and AMA and AMD were assessed. RESULTS: Two (2.0%) patients were diagnosed with SMAS. Postoperative TLK significantly correlated with postoperative AMA (P = 0.013, 0.046). Postoperative ULL was significantly correlated with postoperative AMD (ß = -0.27; P = 0.014). CONCLUSION: The incidence of SMAS after corrective spinal surgery in patients with ASD was 2.0%. Postoperative smaller TLK and greater ULL can be risk factors for developing SMAS. Spine surgeons should avoid overcorrection of the upper lumbar spine in the sagittal plane to prevent SMAS.

The Association Between Corrective Surgery for Adult Spinal Deformity and Serum Levels of Hepatobiliary Enzymes.

Background and objective The surgery to correct adult spinal deformity (ASD) is associated with a rare, but life-threatening complication called acute celiac artery compression syndrome (ACACS). To our knowledge, there is currently no study in the literature regarding the abnormal elevation of serum levels of hepatobiliary enzymes after surgery to correct the deformity. In light of this, the purpose of this study was to investigate this potential association. Materials and methods We collected data on 74 patients with ASD who underwent correction surgery at our institution. A Spearman's rank-order correlation was used to assess the association between serum levels of hepatobiliary enzymes and spinal parameters. Factors showing a correlation coefficient of 0.2 or more were combined in a stepwise multiple regression analysis. Results The mean age of the patients was 68.4 ± 7.7 years; the study comprised six men and 68 women. In our stepwise multiple regression analysis, there were two valid models that included spinal parameters as independent variables: changes in lactate dehydrogenase (LDH) - changes in thoracolumbar kyphosis (TLK) (B -0.0025 ± 0.0007, p<0.01), and changes in LDH - preoperative T12-L1 kyphosis (B 0.0031 ± 0.001, p<0.01). Additionally, both valid models contained median arcuate ligament (MAL) overlap defined as MAL crossing the base of the celiac artery (CA) as a significant independent variable. Conclusions Greater sagittal correction of TLK, larger preoperative T12-L1 kyphosis, and MAL overlap were factors associated with an elevated serum level of LDH. Although few patients were reported to have clinically severe symptoms, "potential" ACACS due to a temporary blood flow disturbance can occur in this patient population.

Risk Factors for Cage Subsidence in Minimally Invasive Lateral Corpectomy for Osteoporotic Vertebral Fractures.

Introduction: This study aims to investigate risk factors for cage subsidence following minimally invasive lateral corpectomy for osteoporotic vertebral fractures. Methods: Eight males and 13 females (77.2±6.0 years old) with osteoporotic vertebral fractures who underwent single corpectomy using a wide-footprint expandable cage with at least a 1-year follow-up were retrospectively included. The endplate cage (EC) angle was defined as the angle between the vertebral body's endplate and the cage's base on the cranial and caudal sides. A sagittal computed tomography scan was performed immediately after surgery and at the final follow-up, with cage subsidence defined as subsidence of ≥2 mm on the cranial or caudal side. Risk factors were analyzed by dividing cases into groups with (n=6) and without (n=15) cage subsidence. Results: No significant differences were noted in age, bone mineral density, number of fixed vertebrae, sagittal parameters, preoperative and final kyphosis angle, amount of kyphosis angle correction, bone union, screw loosening, and number of other vertebral fractures preoperatively and 1-year postoperatively between the two groups. No difference was noted in cranial EC angle, but a significant difference was noted in caudal EC angle in the group with (10.7±4.1°) and without (4.7±4.2°) subsidence (P=0.008). Logistic regression analysis with the dependent variable as presence or absence of subsidence showed that caudal EC angle (>7.5°) was a significant factor (odds ratio: 20, 95% confidence interval: 1.655-241.7, P=0.018). Conclusions: In minimally invasive lateral corpectomy for osteoporotic vertebral fractures, a cage tilted more than 7.5° to the caudal vertebral endplate is a risk factor for cage subsidence. The cage should be placed as perpendicular to the endplate as possible, especially to the caudal vertebral body, to avoid cage subsidence.

Effect of Preoperative Severity and Location of Lumbar Intervertebral Disc Vacuum Phenomenon on Surgical Outcomes After Single-Level Transforaminal Lumbar Interbody Fusion.

OBJECTIVE: This study aimed to examine whether preoperative severity and location of lumbar intervertebral disc vacuum phenomenon (VP) influence surgical outcomes after single-level transforaminal lumbar interbody fusion. METHODS: We included 106 patients (age, 67.4 ± 10.4 years; 51 male/55 female) with lumbar degenerative diseases, who were treated with single-level transforaminal lumbar interbody fusion. Severity of VP (SVP) score was measured preoperatively. SVP score at fused disc was used as SVP (FS) score and at nonfused discs was used as SVP (non-FS) score. Surgical outcomes were assessed using the Oswestry Disability Index (ODI) and visual analog scale (VAS; low back pain (LBP), lower extremity pain, numbness, LBP in motion, in standing, and in sitting). The patients were divided into severe VP (FS or non-FS) and mild VP (FS or non-FS) groups, and surgical outcomes were compared between the 2 groups. Correlations between each SVP score and surgical outcomes were analyzed. RESULTS: There were no differences in surgical outcomes between the severe VP (FS) and mild VP (FS) groups. Postoperative ODI, VAS score for LBP, lower extremity pain, numbness, and LBP in standing were significantly worse in the severe VP (non-FS) group than in the mild VP (non-FS) group. SVP (non-FS) scores significantly correlated with postoperative ODI, VAS score for LBP, lower extremity pain, numbness, and LBP in standing; however, SVP (FS) scores did not correlate with any surgical outcomes. CONCLUSIONS: Preoperative SVP at fused disc is not associated with surgical outcomes; however, SVP at nonfused discs is correlated with clinical outcomes.

Risk factors for celiac artery and superior mesenteric artery stenosis in preoperative lumbar and thoracolumbar spinal surgery patients.

BACKGROUND: Ischemic necrosis of the abdominal organs caused by compression of the celiac artery (CA) and superior mesenteric artery (SMA) by the median arcuate ligament (MAL) after correction surgery has been recognized as acute celiac artery compression syndrome (ACACS). Here, using contrast-enhanced computed tomographic (CT) images, we sought to determine the prevalence and degree of CA and SMA stenosis in spinal patients preoperatively, and the risk factors associated with the stenosis. METHODS: We retrospectively examined contrast-enhanced abdominal CT of 90 patients with preoperative lumbar degenerative disease, lumbar burst fracture, or adult spinal deformity. The trunks of the CA and SMA were detected using three-dimensional reconstructed CT. To investigate their degree of stenosis, we determined the ratio of the narrowest diameter of the stenotic segment to the distal normal lumen's diameter. Patients with a degree of stenosis ≥35% were defined as being in the group with stenosis and the remainder as in the group without. To determine the risk factors for stenosis of these arteries, the relationship between the stenosis and CA and SMA calcification or the median arcuate ligament (MAL) crossing the proximal portion of the celiac axis (MAL overlap) was also investigated. RESULTS: The average degree of stenosis of the CA trunk was 12.1% ± 13.9% and that for the SMA trunk was 8.5% ± 8.8%. There were 8 patients (8.9%) in the group with CA stenosis and 2 patients (2.2%) in the group with SMA stenosis. The number of patients in the group with CA stenosis was significantly greater than the number with MAL overlap or CA calcification (P < 0.05). DISCUSSION: The prevalence of CA or SMA stenosis was 11.2% of preoperative patients due to undergo thoracolumbar fusion surgery. Calcifications of the CA trunk and MAL overlap are risk factors for CA stenosis.