Morphological features of lower lumbar degenerative kyphosis.

PURPOSE: Kyphosis in the lower lumbar spine (L4-S1) significantly affects sagittal alignment. However, the characteristics of the spinopelvic parameters and compensatory mechanisms in patients with lower lumbar degenerative kyphosis (LLDK) have not been described in detail. The objective of this retrospective study was to analyze the morphological characteristics in patients with sagittal imbalance due to LLDK. METHODS: In this retrospective study, we reviewed the clinical records of consecutive patients who underwent corrective surgery for adult spinal deformity (ASD) at a single institution. We defined LLDK as (i) kyphotic deformity in lower lumbar spine (L4-S1) or (ii) inappropriate distribution of lordosis (lordosis distribution index < 40%) in the lower lumbar spine. Global spine parameters of ASD patients and MRI findings were compared between those with LLDK (LLDK group) and without LLDK (control group). RESULTS: A total of 95 patients were enrolled in this study, of which the LLDK group included 14 patients (14.7%). Compared to the control, LLDK presented significantly higher pelvic incidence (62.1° vs 52.6°) and pelvic tilt (40.0° vs 33.4°), larger lordosis at the thoracolumbar junction (12.0° vs -19.6°), and smaller thoracic kyphosis (9.3° vs 26.0°). In LLDK, there was significantly less disc degeneration at L2/3 and L3/4. CONCLUSION: LLDK patients had high pelvic incidence, large pelvic tilt, and a long compensatory curve at the thoracolumbar junction and thoracic spine region.

Pelvic incidence change on the operating table.

PURPOSE: While a change in the pelvic incidence (PI) after long spine fusion surgery has been reported, no studies have examined the change in the PI on the operating table. The present study examined the PI-change on the operating table and elucidated the patients' background characteristics associated with this phenomenon. METHODS: This study included patients who underwent lumbar posterior spine surgery and had radiographs taken in a full-standing position preoperatively and a pelvic lateral radiograph in the prone position in the operative room. The patients with PI-change on the operating table (PICOT; PICOT group) and without PICOT (control group) were compared for their background characteristics and preoperative radiographic parameters. RESULTS: There were 128 eligible patients (62 males, 66 females) with a mean age (± standard deviation) of 69.9 ± 11.7 (range: 25-93) years old. Sixteen patients (12.5%) showed a decrease in the PI > 10°, which indicated placement in the PICOT group. The preoperative lumbar lordosis (LL) and PI-LL in the PICOT group were significantly worse than those in the control group (LL: 20.8 ± 16.6 vs. 30.6 ± 16.2, p = 0.0251, PI-LL: 33.9 ± 19.0 vs. 17.3 ± 14.8, p < 0.0001). The PICOT group had a higher proportion of patients who underwent fusion surgery than the control group, but the difference was not significant (62.5% vs. 44.6%, p = 0.1799). CONCLUSION: A decreased PI was observed in some patients who underwent lumbar posterior surgery on the operating table before surgery. Patients with a PI decrease on the operating table had a significantly worse preoperative global alignment than those without such a decrease. LEVEL OF EVIDENCE I: Diagnostic: individual cross-sectional studies with the consistently applied reference standard and blinding.

Adverse effects of surgeon performance after a night shift on the incidence of perioperative complications in elective thoracolumbar spine surgery.

BACKGROUND: Decline in cognitive function after night shift has been well described. However, in the field of spine surgery, the effect of surgeons' sleeplessness on patient outcome is unclear. The purpose of this study was to investigate whether the risk of perioperative complications in elective thoracolumbar spine surgery could be higher if the surgeon had been on a night shift prior to the day of surgery. METHODS: We performed a retrospective review of patients who underwent elective posterior thoracolumbar spine surgery, as indicated in medical records, between March 2015 and September 2018. In total, 1189 patients were included and divided into two groups: the post-nighttime (n = 110) and control groups (n = 1079). A post-nighttime case was defined when the operating surgeon was on nighttime duty on the previous night, and other cases were defined as controls. We evaluated the incidence of perioperative complications (surgical site infection, postoperative hematoma, postoperative paralysis, nerve root injury, and dural tear) in both groups. RESULTS: Overall, we found no significant difference in the major or minor perioperative complication rates between the two groups, but according to the type of complication, the incidence rate of dural tear tended to be higher in the post-nighttime group (13.6% vs 8.2%, P = 0.074). Multivariate analysis showed that post-nighttime status was an independent risk factor of dural tear (adjusted odds ratio, 2.02; 95% confidence interval [CI], 1.10-3.70; P = 0.023). After stratification by surgical complexity, post-nighttime status was an independent risk factor of dural tear only in the surgeries of 3 levels or more (adjusted odds ratio, 2.81; 95% CI, 1.18-6.67; P = 0.019). CONCLUSIONS: Post-nighttime status was generally not a risk factor of perioperative complications in elective posterior thoracolumbar spine surgeries, but was an independent risk factor of dural tear, especially in complex cases.

The usefulness of neutrophil CD64 expression for diagnosing infection after orthopaedic surgery in dialysis patients.

BACKGROUND: Dialysis patients undergoing orthopaedic surgery are at high risk for postoperative infection. Diagnosis of postoperative infection is difficult in dialysis patients due to presentation of signs and symptoms similar to infection, such as fever and elevated inflammatory marker levels. Neutrophil CD64 expression (CD64), a marker of infection, is upregulated by microbial wall components and several cytokines (interferon-γ and tumor necrosis factor-α). The purpose of this study is to evaluate the usefulness of CD64 for diagnosing postoperative infection in dialysis patients post orthopaedic surgery. PATIENTS AND METHODS: Between 2013 and 2014, we prospectively studied 36 dialysis patients (18 men, 18 women; mean age 65.9 years; 49 to 83) who underwent orthopaedic surgery. Dialysis patients were classified into three groups according to their postoperative course as follows; non-infected patients, infection suspected patients, and infected patients. Inflammatory markers such as white blood cell count (WBC), C-reactive protein (CRP) and CD64 were measured before operation and one week after surgery. Using the receiver-operating characteristic (ROC) curve and Akaike's Information Criterion (AIC), the cutoff value of CD64 and CRP was calculated leading to a determination of which inflammatory marker is best accurate for detecting postoperative infection. RESULTS: We found that postoperative CD64 and CRP levels presented a statistically significant difference between infected patients and non-infected patients (p < 0.05). Furthermore, comparison of the ROC curve and AIC value between postoperative CD64 and CRP levels exhibited that CD64 was more accurate infectious marker than CRP. CONCLUSION: CD64 is a useful marker for detecting postoperative infection after orthopaedic surgery in dialysis patients.

Neuromyelitis Optica Spectrum Disorders (NMOSDs) Diagnosed After Surgery for the Ossification of the Posterior Longitudinal Ligament of the Cervical and Thoracic Spine: A Case Report.

Complications of compressive spinal cord myelopathy and demyelinating disease can be difficult to diagnose. A 65-year-old woman gradually lost the ability to walk. Her imaging findings showed multiple spinal canal stenosis and ossification of the posterior longitudinal ligament in the cervical and thoracic spine. Some intramedullary signal changes were seen at sites distant from the spinal cord compression site. Although she underwent cervical and thoracic decompression and fusion surgery relatively early, her lower-extremity strength decreased after surgery. Her aquaporin 4 (AQP4)-antibody was found to be positive postoperatively, and she was diagnosed with NMOSD. Medical treatment for NMOSD improved her walking ability, and she finally became able to walk with a cane. In cases where there is a discrepancy between the site of strong stenosis and intramedullary signal changes, it is necessary to consider an anti-AQP4 antibody test and consultation with a neurologist.

Two-year results of single-level fixation with lateral mass screws for cervical degenerative spondylolisthesis: patient series.

BACKGROUND: In surgery for cervical spondylotic myelopathy (CSM) with spondylolisthesis, there is no consensus on the correction and fixation for spondylolisthesis. The authors retrospectively studied whether the correction of single-level fixation with lateral mass screws (LMSs) could be maintained. OBSERVATIONS: The records of patients with CSM with spondylolisthesis who had been treated with posterior decompression and single-level fusion with LMSs from 2017 to 2021 were retrospectively reviewed. Radiographic measurements included cervical parameters such as C2-7 lordosis, T1 slope, and the degree of spondylolisthesis (percent slippage) before surgery, immediately after surgery, and at the final observation. Ten cases (mean age 72.8 ± 7.8 years) were included in the final analysis, and four cases (40%) were on hemodialysis. The median observation period was 26.5 months (interquartile range, 12-35.75). The mean percent slippage was 16.8% ± 4.7% before surgery, 5.3% ± 4.0% immediately after surgery, and 6.5% ± 4.7% at the final observation. Spearman's rank correlation showed a moderate correlation between preoperative slippage magnitude and correction loss (r = 0.659; p = 0.038). Other parameters showed no correlation with correction loss. LESSONS: For CSM with spondylolisthesis, single-level fixation with LMSs achieved and maintained successful correction in the 2-year observation.

The clinical utility of a one-shot energy subtraction method for thoracic spine radiography.

BACKGROUND: The interpretation of thoracic spine X-rays is difficult because these images cannot clearly visualize the thoracic spine because of the overlap with soft tissues, such as the heart and pulmonary blood vessels. Thus, to improve the clarity of thoracic spine radiographs using existing radiograph equipment, we have investigated a one-shot energy subtraction method to visualize thoracic spine radiographs. Our objective was to evaluate whether the thoracic spine radiographs generated using this method could visualize the spine more clearly than the corresponding original thoracic spine radiographs. METHODS: This study included 29 patients who underwent thoracic spine radiographs. We used a one-shot energy subtraction method to improve the clarity of thoracic spine radiographs. Image definition was evaluated using vertebrae sampled from each region of the thoracic spine. Specifically, these were: Th1, Th5, Th9, and Th12. Image definition was assessed using a three-point grading system. The conventional and processed computed radiographs (both frontal and lateral views) of all 29 study patients were evaluated by 5 spine surgeons. RESULTS: In all thoracic regions on both frontal and lateral views, the processed images showed statistically significantly better clarity than the corresponding conventional images, especially at all sampling sites on the frontal view and T5 and 9 on the lateral view. CONCLUSIONS: Thoracic spine radiographs generated using this method visualized the spine more clearly than the corresponding original thoracic spine radiographs. The greatest advantages of this image processing technique were its ability to clearly depict the whole thoracic spine on frontal views and the middle thoracic spine on lateral views.

Association Between Paravertebral Muscle Mass and Improvement in Sagittal Imbalance After Decompression Surgery of Lumbar Spinal Stenosis.

STUDY DESIGN: Retrospective observational study. OBJECTIVE: This study examined associated factors for the improvement in spinal imbalance following decompression surgery without fusion. SUMMARY OF BACKGROUND DATA: Several reports have suggested that decompression surgery without fusion may have a beneficial effect on sagittal balance in patients with lumbar spinal stenosis (LSS) through their postoperative course. However, few reports have examined the association between an improvement in sagittal imbalance and spinal sarcopenia. METHODS: We retrospectively reviewed 92 patients with LSS and a preoperative sagittal vertical axis (SVA) more than or equal to 40 mm who underwent decompression surgery without fusion at a single institution between April 2017 and October 2018. Patients' background and radiograph parameters and the status of spinal sarcopenia, defined using the relative cross-sectional area (rCSA) of the paravertebral muscle (PVM) and psoas muscle at the L4 caudal endplate level, were assessed. We divided the patients into two groups: those with a postoperative SVA less than 40 mm (balanced group) and those with a postoperative SVA more than or equal to 40 mm (imbalanced group). We then compared the variables between the two groups. RESULTS: A total of 29 (31.5%) patients obtained an improved sagittal imbalance after decompression surgery. The rCSA-PVM in the balanced group was significantly higher than that in the imbalanced group (P = 0.042). The preoperative pelvic incidence (PI)-lumbar lordosis (LL) mismatch (P = 0.048) and the proportion with compression vertebral fracture (P = 0.028) in the balanced group were significantly lower than those in the imbalanced group. A multivariate logistic regression analysis identified PI-LL less than or equal to 10° and rCSA-PVM more than or equal to 2.5 as significant associated factor for the improvement in spinal imbalance following decompression surgery. CONCLUSION: A larger volume of paravertebral muscles and a lower PI-LL were associated with an improvement in sagittal balance in patients with LSS who underwent decompression surgery.Level of Evidence: 3.

The standing T1-L1 pelvic angle: a useful radiographic predictor of proximal junctional kyphosis in adult spinal deformity.

OBJECTIVE: Proximal junctional kyphosis (PJK), which can worsen a patient's quality of life, is a common complication following the surgical treatment of adult spinal deformity (ASD). Although various radiographic parameters have been proposed to predict the occurrence of PJK, the optimal method has not been established. The present study aimed to investigate the usefulness of the T1-L1 pelvic angle in the standing position (standing TLPA) for predicting the occurrence of PJK. METHODS: The authors retrospectively extracted data for patients with ASD who underwent minimum 5-level fusion to the pelvis with upper instrumented vertebra between T8 and L1. In the present study, PJK was defined as ≥ 10° progression of the proximal junctional angle or reoperation due to progressive kyphosis during 1 year of follow-up. The following parameters were analyzed on whole-spine standing radiographs: the T1-pelvic angle, conventional thoracic kyphosis (TK; T4-12), whole-thoracic TK (T1-12), and the standing TLPA (defined as the angle formed by lines extending from the center of T1 and L1 to the femoral head axis). A logistic regression analysis and a receiver operating characteristic curve analysis were performed. RESULTS: A total of 50 patients with ASD were enrolled (84% female; mean age 74.4 years). PJK occurred in 19 (38%) patients. Preoperatively, the PJK group showed significantly greater T1-pelvic angle (49.2° vs 34.4°), conventional TK (26.6° vs 17.6°), and standing-TLPA (30.0° vs 14.9°) values in comparison to the non-PJK group. There was no significant difference in the whole-thoracic TK between the two groups. A multivariate analysis showed that the standing TLPA and whole-thoracic TK were independent predictors of PJK. The standing TLPA had better accuracy than whole-thoracic TK (AUC 0.86 vs 0.64, p = 0.03). The optimal cutoff value of the standing TLPA was 23.0° (sensitivity 0.79, specificity 0.74). Using this cutoff value, the standing TLPA was the best predictor of PJK (OR 8.4, 95% CI 1.8-39, p = 0.007). CONCLUSIONS: The preoperative standing TLPA was more closely associated with the occurrence of PJK than other radiographic parameters. These results suggest that this easily measured parameter is useful for the prediction of PJK.

Factors Associated with Retro-Odontoid Pseudotumor in Long-Term Hemodialysis Patients.

OBJECTIVE: Hemodialysis has been reported to be associated with retro-odontoid pseudotumor (ROP), but its clinical characteristics have not been well described. The purpose of the present study was to investigate the factors associated with ROP in hemodialysis patients. METHODS: A retrospective clinical study of hemodialysis patients was conducted with the evaluation of computed tomography and magnetic resonance imaging of cervical spinal lesions at a single institution from 2012 to 2020. The patients' characteristics and radiographic findings were assessed. A case-control analysis was performed between patients with ROP (ROP group) and patients without ROP (control group). RESULTS: We analyzed 46 patients. The mean duration of hemodialysis (± standard deviation) was 21.5 ± 11.8 years. The mean retro-odontoid soft tissue thickness was 4.3 ± 0.3 mm and was correlated with the duration of hemodialysis (r = 0.46, P < 0.01). Thirty patients (65.2%) were included in the ROP group. The ROP group showed a significantly longer duration of hemodialysis (24.9 ± 11.2 years vs. 15.2 ± 10.3 years, P < 0.01) and a higher incidence of osteolytic lesions in the atlantoaxial joint compared with the control group (60.0% vs. 18.8%, P < 0.01). Logistic regression analysis revealed the atlantoaxial osteolytic lesions are associated with retro-odontoid pseudotumor in hemodialysis patients (odds ratio, 5.1; 95% confidence interval, 1.1-24.2; P = 0.04). CONCLUSIONS: The existence of ROP in hemodialysis patients was associated with osteolytic lesions in the atlantoaxial joint. The finding of atlantoaxial erosive lesions in long-term hemodialysis patients requires spine surgeons to carefully evaluate the presence of ROP.

Dynamization-Posterior Lumbar Interbody Fusion for Hemodialysis-Related Spondyloarthropathy: Evaluation of the Radiographic Outcomes and Reoperation Rate within 2 Years Postoperatively.

STUDY DESIGN: Clinical case series. PURPOSE: This study aimed to report dynamization-posterior lumbar interbody fusion (PLIF), our surgical treatment for hemodialysisrelated spondyloarthropathy (HSA), and investigate patients' postoperative course within 2 years. OVERVIEW OF LITERATURE: HSA often requires lumbar fusion surgery. Conventional PLIF for HSA may cause progressive destructive changes in the vertebral endplate, leading to progressive cage subsidence, pedicle screw loosening, and pseudoarthrosis. A dynamic stabilization system might be effective in patients with a poor bone quality. Thus, we performed "dynamization-PLIF" in hemodialysis patients with destructive vertebral endplate changes. METHODS: We retrospectively examined patients with HSA who underwent dynamization-PLIF at our hospital between April 2010 and March 2018. The radiographic measurements included lumbar lordosis and local lordosis in the fused segment. The evaluation points were before surgery, immediately after surgery, 1 year after surgery, and 2 years after surgery. The preoperative and postoperative radiographic findings were compared using a paired t-test. A p-value of less than 0.05 was considered significant. RESULTS: We included 50 patients (28 males, 22 females). Lumbar lordosis and local lordosis were significantly improved through dynamization- PLIF (lumbar lordosis, 28.4°-35.5°; local lordosis, 2.7°-12.8°; p<0.01). The mean local lordosis was maintained throughout the postoperative course at 1- and 2-year follow-up (12.9°-12.8°, p=0.89 and 12.9°-11.8°, p=0.07, respectively). Solid fusion was achieved in 59 (89%) of 66 fused segments. Solid fusion of all fixed segments was achieved in 42 cases (84%). Within 2 years postoperatively, only six cases (12%) were reoperated (two, surgical debridement for surgical site infection; two, reoperation for pedicle screw loosening; one, laminectomy for epidural hematoma; one, additional fusion for adjacent segment disease). CONCLUSIONS: Dynamization-PLIF showed local lordosis improvement, a high solid fusion rate, and a low reoperation rate within 2 years of follow-up.

Medialization of Common Carotid Artery Is Associated with Cervical Kyphosis.

INTRODUCTION: Reportedly, the medialization of the common carotid artery (MCCA) to be a vascular anomaly with a potential risk of intraoperative carotid artery injury. Nevertheless, among spine surgeons, the presence of MCCA has not been well recognized. METHODS: We retrospectively reviewed consecutive patients who underwent cervical radiographs and magnetic resonance imaging (MRI) examinations in a single spine center. Using MRI, the MCCA grade was classified into grades 1 to 3 in order of severity. Radiographic measurement included C2-C7 angles as cervical lordosis, cervical sagittal vertical axis (C-SVA), T1 slope (T1S), and T1S-cervical lordosis mismatch. We compared each patient's background and radiographic parameters between patients with each of the three MCCA grades. The continuous variables were compared using the Jonckheere-Terpstra trend test and the proportions were compared using the Cochran-Armitage trend test to investigate the trend of variables in three grades. RESULTS: The present study included data from 133 eligible patients (65 males and 68 females) with a mean age of 63.7 (±14.2) years. The details of MCCA grading were as follows: grade 1, n=101; grade 2, n=27; and grade 3, n=5. With an increasing MCCA grade, age (61.9±14.0, 68.2±13.8, and 76.4±9.4 years for grades 1, 2, and 3, respectively, p=0.005) and proportion of female (p<0.001) had an increasing trend, whereas cervical lordosis had a decreasing trend (11.7±13.5°, 7.0±14.5°, and -10.0±19.2° for grades 1, 2, and 3, respectively, p=0.011). CONCLUSIONS: Several patient backgrounds including the female gender, older age, and kyphotic alignment were determined as MCCA risk factors. Careful preoperative neck vasculature assessment would avoid a catastrophic complication during anterior cervical surgery.

The Utility of the Energy Subtraction Method for Thoracic Spine Radiography in Clinical Practice: An Analysis of 25 Patients With Multiple Myeloma.

Interpretation of thoracic spine radiographs is difficult because they cannot clearly depict the vertebrae due to overlap with soft tissues. This study aimed to evaluate whether thoracic spine radiographs obtained using the energy subtraction method could improve the accuracy of a diagnosis of thoracic osteolytic lesions. The authors analyzed 300 thoracic vertebrae from 25 patients with multiple myeloma who underwent thoracic spine radiography. All patients underwent thoracic spine radiography with 2 views. Two sets of images were prepared: computed radiography images (CR images) acquired using conventional processing parameters; and processed images for specifically visualizing bone, using the energy subtraction method (ES images). The CR images (CR group) and paired CR and ES images (CR+ES group) were interpreted in parallel by 5 orthopedic surgeons. The presence of osteolytic lesions was evaluated for each of the 12 thoracic vertebrae, and the sensitivity and specificity of the method were compared with computed tomography (CT), which is considered the gold standard. Subgroup analysis was also performed based on location. Osteolytic lesions were found on CT in 28 (9.3%) vertebrae of 12 patients. The overall sensitivities and specificities of the CR and CR+ES groups were 17.2% and 54.3%, respectively, and 95.6% and 98.0%, respectively, with statistically significant differences. Subgroup analysis showed particular improvement in the sensitivity for the CR+ES group in the middle thoracic spine compared with that at other locations. Thoracic spine radiographs generated using this method may improve the accuracy of diagnosis of thoracic osteolytic lesions. [Orthopedics. 2021;44(1):e31-e35.].

Preventive Effect of Dynamic Stabilization Against Adjacent Segment Degeneration After Posterior Lumbar Interbody Fusion.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To investigate the effects of dynamic stabilization with sublaminar taping (ST) on the upper segment adjacent to posterior lumbar interbody fusion (PLIF). SUMMARY OF BACKGROUND DATA: Hybrid procedures such as dynamic stabilization for adjacent segment in addition to spinal fusion have been developed for reduction of the mechanical stress and prevention of adjacent segment pathology (ASP). However, a few reports are available on hybrid procedures and their efficacy is still controversial. METHODS: Of the 116 patients who underwent L4/5 PLIF between August 2006 and September 2012, 76 patients with minimum 2-year follow up were included in this study. Fifty three patients underwent L4/5 PLIF with hybrid procedure using ST on L3 lamina (group U), and 23 patients underwent conventional L4/5 PLIF (group C). The adjacent segment degeneration (ASDeg) was determined by measurements of radiograph, computed tomography, and magnetic resonance imaging; the adjacent segment disease (ASDis) was evaluated on medical records. RESULTS: The incidence of ASDeg at L3/4 segment of group U (3.7%) was significantly less than that of group C (30.4%) (P = 0.003), although there were no significant differences at L2/3 (group U, 7.5%; group C, 13%) or L5/S1 segment (group U, 5.7%; group C, 8.7%). On the other hand, no significant difference was found between two groups in the incidence of ASDis in L2/3 to L5/S1 levels, and no patient underwent reoperation. Bivariable and multivariable logistic regression analyses for L3/4 segment ASDeg revealed that the difference of surgical procedure was the only significant factor. CONCLUSION: The current study showed that L4/5 PLIF with hybrid procedure using ST on L3 lamina significantly reduced the incidence of L3/4 ASDeg as compared with the conventional L4/5 PLIF without compromising L2/3 or L5/S1 segment. Although further studies and longer follow up are necessary, the hybrid procedure is expected to be effective for preventing ASP. LEVEL OF EVIDENCE: 4.

Anterior cage dislodgement in posterior lumbar interbody fusion: a review of 12 patients.

OBJECTIVE Interbody fusion cages are widely used to achieve initial fixation and secure spinal fusion; however, there are certain technique-related complications. Although anterior cage dislodgement can cause major vascular injury, the incidence is extremely rare. Here, the authors performed a review of anterior cage dislodgement following posterior lumbar interbody fusion (PLIF) surgery. METHODS The authors retrospectively reviewed the cases of 4625 patients who had undergone PLIF at 6 institutions between December 2007 and March 2015. They investigated the incidence and causes of surgery-related anterior cage dislodgement, salvage mechanisms, and postoperative courses. RESULTS Anterior cage dislodgement occurred in 12 cases (0.26%), all of which were caused by technical errors. In 9 cases, excessive cage impaction resulted in dislodgement. In 2 cases, when the cage on the ipsilateral side was inserted, it interacted and pushed out the other cage on the opposite side. In 1 case, the cage was positioned in an extreme lateral and anterior part of the intervertebral disc space, and it postoperatively dislodged. In 3 cases, the cage was removed in the same operative field. In the remaining 9 cases, CT angiography was performed postoperatively to assess the relationship between the dislodged cage and large vessels. Dislodged cages were conservatively observed in 2 cases. In 7 cases, the cage was removed because it was touching or compressing large vessels, and an additional anterior approach was selected. In 2 patients, there was significant bleeding from an injured inferior vena cava. There were no further complications or sequelae associated with the dislodged cages during the follow-up period. CONCLUSIONS Although rare, iatrogenic anterior cage dislodgement following a PLIF can occur. The authors found that technical errors made by experienced spine surgeons were the main causes of this complication. To prevent dislodgement, the surgeon should be cautious when inserting the cage, avoiding excessive cage impaction and ensuring cage control. Once dislodgement occurs, the surgeons must immediately address this difficult complication. First, the possibility of a large vessel injury should be considered. If the patient's vital signs are stable, the surgeon should continue with the surgery without cage removal and perform CT angiography postoperatively to assess the cage location. Blind maneuvers should be avoided when the surgical site cannot be clearly viewed. When the cage compresses or touches the aortic artery or vena cava, it is better to remove the cage to avoid late-onset injury to major vessels. When the cage does not compress or touch vessels, its removal is controversial. The risk factors associated with performing another surgery should be evaluated on a case-by-case basis.

Predictive Factors for Subjective Improvement in Lumbar Spinal Stenosis Patients with Nonsurgical Treatment: A 3-Year Prospective Cohort Study.

OBJECTIVE: To assess the predictive factors for subjective improvement with nonsurgical treatment in consecutive patients with lumbar spinal stenosis (LSS). MATERIALS AND METHODS: Patients with LSS were enrolled from 17 medical centres in Japan. We followed up 274 patients (151 men; mean age, 71 ± 7.4 years) for 3 years. A multivariable logistic regression model was used to assess the predictive factors for subjective symptom improvement with nonsurgical treatment. RESULTS: In 30% of patients, conservative treatment led to a subjective improvement in the symptoms; in 70% of patients, the symptoms remained unchanged, worsened, or required surgical treatment. The multivariable analysis of predictive factors for subjective improvement with nonsurgical treatment showed that the absence of cauda equina symptoms (only radicular symptoms) had an odds ratio (OR) of 3.31 (95% confidence interval [CI]: 1.50-7.31); absence of degenerative spondylolisthesis/scoliosis had an OR of 2.53 (95% CI: 1.13-5.65); <1-year duration of illness had an OR of 3.81 (95% CI: 1.46-9.98); and hypertension had an OR of 2.09 (95% CI: 0.92-4.78). CONCLUSIONS: The predictive factors for subjective symptom improvement with nonsurgical treatment in LSS patients were the presence of only radicular symptoms, absence of degenerative spondylolisthesis/scoliosis, and an illness duration of <1 year.

[Indication and surgical methods of lumbosacral spinal fusion for lumbal degenerative diseases].

In degenerative lumbar spinal diseases with low back pain and leg pain, the indications for lumbar spinal fusion are not clear. It is unclear for the following reasons. The definition of instability is not clear. And it is also difficult to observe the exact source of the low back pain. In addition, there are limited numbers of randomized prospective study about the usefulness of spine fusion. Controversy still exists for when spinal instrumentation should be used. A spinal surgeon performs a posterolateral fusion or a posterior interbody fusion with or without instrumentation, mainly based on his experience and belief.

Single-stage Anterior and Posterior Fusion Surgery for Correction of Cervical Kyphotic Deformity Using Intervertebral Cages and Cervical Lateral Mass Screws: Postoperative Changes in Total Spine Sagittal Alignment in Three Cases with a Minimum Follow-up of Five Years.

The surgical treatment of cervical kyphotic deformity remains challenging. As a surgical method that is safer and avoids major complications, the authors present a procedure of single-stage anterior and posterior fusion to correct cervical kyphosis using anterior interbody fusion cages without plating, as illustrated by three consecutive cases. Case 1 was a 78-year-old woman who presented with a dropped head caused by degeneration of her cervical spine. Case 2 was a 54-year-old woman with athetoid cerebral palsy. She presented with cervical myelopathy and cervical kyphosis. Case 3 was a 71-year-old woman with cervical kyphotic deformity following a laminectomy. All three patients underwent anterior release and interbody fusion with cages and posterior fusion with cervical lateral mass screw (LMS) fixation. Postoperative radiographs showed that correction of kyphosis was 39° in case 1, 43° in case 2, and 39° in case 3. In all three cases, improvement of symptoms was established without major perioperative complications, solid fusion was achieved, and no loss of correction was observed at a minimum follow-up of 61 months. We also report that preoperative total spine sagittal malalignment was improved after corrective surgery for cervical kyphosis and was maintained at the latest follow-up in all three cases. The combination of anterior fusion cages and LMS is considered a safe and effective procedure in cases of severe cervical kyphotic deformity. Preoperative total spine sagittal malalignment improved, accompanied by correction of cervical kyphosis, and was maintained at last follow-up in all three cases.