Long-term outcomes of spine surgery in dialysis patients, focusing on activities of daily living, life expectancy, and the risk factors for postoperative mortality.

BACKGROUND: Because of the high incidence of major perioperative adverse events, spine surgery in dialysis patients should be recommended carefully after consideration of its risks and benefits. However, the benefits of spine surgery in dialysis patients remain unclear because of the lack of long-term outcomes. The purpose of this study is to elucidate the long-term outcomes of spine surgery in dialysis patients, focusing on activities of daily living (ADLs), life expectancy, and risk factors for postoperative mortality. METHODS: Data for 65 dialysis patients who underwent spine surgery at our institution and were followed up for a mean duration of 6.2 years were retrospectively reviewed. ADLs, number of surgeries, and survival times were recorded. The postoperative survival rate was calculated using the Kaplan-Meier method, and risk factors for postoperative mortality were investigated using a generalized Wilcoxon test and multivariate Cox proportional-hazards model. RESULTS: Compared with preoperative ADLs, ADLs significantly improved at discharge after surgery and at the final follow-up. However, 16 of the 65 patients (24.6%) underwent multiple surgeries, and 34 (52.3%) died during the follow-up period. Kaplan-Meier analysis revealed that the survival rate after spine surgery was 95.4% at 1 year, 86.2% at 3 years, 69.6% at 5 years, 59.7% at 7 years, and 28.7% at 10 years, and the overall median survival time was 99 months. Multivariate Cox regression analysis showed that a dialysis period of ≥10 years was a significant risk factor. CONCLUSIONS: Spine surgery in dialysis patients improved and maintained ADLs in the long term and did not shorten life expectancy. However, dialysis patients undergoing spine surgery require multiple surgeries more frequently, and a dialysis period of ≥10 years is a significant risk factor for postoperative mortality.

Factors related to length of hospital stay after two-stage corrective surgery for adult spinal deformity in elderly Japanese.

BACKGROUND: Postoperative recovery of activities of daily living after surgery in elderly patients often takes a longer time because of their frailty. However, it is unclear how long it takes for patients with adult spinal deformity (ASD) to recover their abilities to live their daily lives in their home after corrective fusion surgery. This study aimed to investigate the length of hospital stay required to perform activities of daily living (ADL) in patients undergoing two-stage corrective fusion surgery for ASD in our institution and to detect factors associated with the length of hospital stay. METHODS: Thirty-four consecutive female ASD patients (median age, 70 years) who underwent two-stage corrective fusion surgery (lateral lumbar interbody fusion at the first stage and posterior corrective fusion at the second stage) from T9 or T10 to the pelvis were included. The length of hospital stay from admission to return home was determined, and correlations between length of hospital stay and demographics, skeletal muscle mass, operative invasion and perioperative complications, and spino-pelvic alignment were investigated. RESULTS: The median length of hospital stay was 51 days, exceeding 100 days in 25% of cases. Age at surgery (ρ = 0.545, p = 0.001), estimated glomerular filtration rate (ρ = -0.603, p < 0.001), age-adjusted Charlson comorbidity index (ρ = 0.437, p = 0.01), and preoperative pelvic incidence (ρ = 0.356, p = 0.04) were correlated with length of hospital stay. Preoperative skeletal muscle mass, preoperative spinal imbalance, perioperative changes in spino-pelvic alignment, operative invasion, and perioperative complications were not correlated with length of hospital stay. CONCLUSIONS: After >50 days, ADL performance of each patient reached the extent required for daily living to return home after two-stage corrective fusion surgery for ASD. Factors related to length of hospital stay were age and indices related to frailty.

Resting-state Amplitude of Low-frequency Fluctuation is a Potentially Useful Prognostic Functional Biomarker in Cervical Myelopathy.

BACKGROUND: Cervical MRI is the standard diagnostic imaging technique for patients with cervical myelopathy. However, the utility of conventional cervical MRI as a predictive biomarker for surgical recovery remains unclear, partly because of the limited information obtained from this anatomically small area. Brain resting-state functional MRI (rs-fMRI) may help identify candidate predictive biomarkers. Two analytical methods that assess local spontaneous brain activity are widely used for rs-fMRI: functional connectivity between two brain regions and amplitude of low-frequency fluctuation (ALFF). In our previous analysis of functional connectivity, we discovered that brain functional connectivity may be a predictive biomarker for neurologic recovery in patients with cervical myelopathy; however, the functional connectivity analysis identified a correlation with only one clinical outcome (the 10-second test). To establish a comprehensive prediction measure, we need to explore other brain biomarkers that can predict recovery of other clinical outcomes in patients with cervical myelopathy. QUESTIONS/PURPOSES: We aimed to (1) elucidate preoperative ALFF alterations in patients with cervical myelopathy and how ALFF changes after surgery, with a focus on postoperative normalization and (2) establish a predictive model using preoperative ALFF by investigating the correlation between preoperative ALFF and postoperative clinical recovery in patients with cervical myelopathy. METHODS: Between August 2015 and June 2017, we treated 40 patients with cervical myelopathy. Thirty patients met our prespecified inclusion criteria, all were invited to participate, and 28 patients opted to do so (93%; 14 men and 14 women; mean age: 67 years). The 28 patients and 28 age- and sex-matched controls underwent rs-fMRI (twice for patients with cervical myelopathy: before and 6 months after cervical decompression surgery). We analyzed the same study population that was used in our earlier study investigating functional connectivity. Controls had none of the following abnormalities: neck or arm pain, visual or auditory disorders, cognitive disorder, structural brain disorder, a history of brain surgery, mental and neurologic disorders, and medications for the central nervous system. We performed ALFF comparisons between preoperative patients with cervical myelopathy and controls, analyzed postoperative ALFF changes in patients with cervical myelopathy, and performed a correlation analysis between preoperative ALFF and clinical recovery in these patients. Clinical outcomes in the cervical myelopathy group were assessed using the 10-second test, the Japanese Orthopaedic Association upper-extremity motor (JOA-UEM) score, JOA upper-extremity sensory score (JOA-UES), and Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire for upper-extremity function (JOACMEQ-UEF) score before and 6 months after surgery, which is when we believe these scores generally reach a plateau. A total of 93% of those enrolled (26 of 28 patients) were analyzed both preoperatively and postoperatively; the other two were lost to follow-up. RESULTS: The cervical myelopathy group had an increase in ALFF in the bilateral primary sensorimotor cortices (right, cluster size = 850 voxels, t-value = 6.10; left, cluster size = 370 voxels, t-value = 4.84) and left visual cortex (cluster size = 556 voxels, t-value = 4.21) compared with the control group. The cervical myelopathy group had a decrease in ALFF in the bilateral posterior supramarginal gyrus (right, cluster size = 222 voxels, t-value = 5.09; left, cluster size = 436 voxels, t-value = 5.28). After surgery, the bilateral sensorimotor cortices (right, cluster size = 468 voxels, t-value = 6.74; left, cluster size = 167 voxels, t-value = 5.40) and left visual cortex (cluster size = 3748 voxels, t-value = 6.66) showed decreased ALFF compared with preoperative ALFF, indicating postoperative normalization of spontaneous brain activities in these regions. However, the bilateral posterior supramarginal gyrus did not show an increase in ALFF postoperatively, although ALFF in this region decreased preoperatively. Greater levels of ALFF at the left and right frontal pole and left pars opercularis of the inferior frontal gyrus before surgery in the cervical myelopathy group were correlated with larger improvements in the JOACMEQ-UEF score 6 months after surgery (r = 0.784; p < 0.001, r = 0.734; p < 0.001 and r = 0.770, respectively; p < 0.001). The prediction formula, based on preoperative ALFF values in the left frontal pole, was as follows: the predicted postoperative improvement in the JOACMEQ-UEF score = 34.6 × preoperative ALFF value - 7.0 (r = 0.614; p < 0.001). CONCLUSIONS: Our findings suggest that preoperative ALFF may be a biomarker for postoperative recovery in that it predicted postoperative JOACMEQ-UEF scores. To establish a comprehensive prediction measure for neurologic recovery in patients with cervical myelopathy, a multicenter study is underway. LEVEL OF EVIDENCE: Level II, diagnostic study.

Influence of novel design alteration of pedicle screw on pull-out strength: A finite element study.

BACKGROUND: We conducted a finite element study to assess the effectiveness of a novel pedicle screw design with two alterations in the distal and proximal portions. METHODS: Finite element (FE) models of 24 vertebrae were constructed using computed tomographic data. Pull-out strength of 4 different pedicle screws were compared. The basic screw design was a dual threaded one (PS0), in which the proximal portion is double-threaded (cortical thread), and the distal portion is single-threaded (cancellous thread). In PS1, the inter-thread double-core shape was added to PS0 in the distal portion. Compared to PS0, in PS2, the proximal portion was elongated by 5 mm. PS3 had both PS1 and PS2 features. In addition, the 24 vertebrae were classified into 3 groups based on volumetric bone mineral density (vBMD) of the vertebral body: low <120 mg/cm3, moderate 120-170 mg/cm3, and high >170 mg/cm3. RESULTS: The mean pull-out strengths (±SD) were 1137 ± 500 N, 1188 ± 520 N, 1191 ± 512 N, and 1242 ± 538 N for PS0, PS1, PS2, and PS3, respectively. In PS1, there was significant difference in the incremental ratio of pull-out strength to PS0 between the low and high vBMD groups (3.7 ± 1.6% vs. 5.0 ± 1.0%, p = 0.006). In PS2, there was a significant difference in the incremental ratio to PS0 between the moderate and high vBMD groups (7.6 ± 4.0% vs. 3.3 ± 1.8%, p < 0.001). In PS3, there was a significant difference in the incremental ratio to PS0 between the moderate and high vBMD groups (12.1 ± 4.8% vs. 8.5 ± 2.1%, p = 0.003). CONCLUSIONS: The two design alterations showed the combined additive effect in the PS3 design. The moderate vBMD group has a balanced bone property to reflect the combined effects of the PS1 and PS2 design alterations.

Predictors for progression of two different types of cervical lesions in rheumatoid arthritis treated with biologic agents.

BACKGROUND: Biologic agents (BAs) enabled not only a reduction of disease activity but also a slowing down of structural damage to the joints in patients with rheumatoid arthritis (RA). However, the incidence of cervical lesions in patients with RA is still high. PURPOSE: To elucidate the predictors for the progression of two different cervical lesions in patients with RA under BA treatment. METHODS: Of 151 subjects who received more than two years of continuous BA treatment, 101 subjects who had cervical X-ray images taken at baseline and final visit were enrolled. The mean disease duration and mean radiography interval were 10.6 years and 4.4 years, respectively. The existence and progression of cervical lesions (atlanto-axial subluxation [AAS], vertical subluxation [VS], and subaxial subluxation [SS]) were investigated. And predictors for the AAS or VS progression were analyzed by multivariate logistic regression analysis. RESULTS: The incidence of cervical lesions at baseline were no pre-existing cervical lesion (none) in 50 cases (50%), AAS only in 32 (32%), both AAS and VS in 12 (12%), and VS only in 7 cases (7%). In the none group, only 4 cases of AAS progression (8%) was observed during the follow-up. In contrast, in the groups with pre-existing cervical lesions, a high incidence of VS progression was observed (63% in the AAS only group, 58% in the AAS + VS group, and 71% in the VS only group). Multivariate regression analysis demonstrated that the DAS-CRP value at baseline (odds ratio [OR] = 9.23) and matrix metaloprotease-3 level at baseline (OR = 1.01) were significant predictors for the progression of AAS, and pre-existing AAS (OR = 18.38) was a sole significant predictor for the progression of VS. CONCLUSIONS: Cervical lesions progressed irrespective of disease activity after AAS development. Strict disease control before the development of AAS is crucial for preventing further progression and development of cervical lesions.

Complications after spinal fixation surgery for osteoporotic vertebral collapse with neurological deficits: Japan Association of Spine Surgeons with ambition multicenter study.

BACKGROUND: There have been few reports on the incidence and risk factors of the complications after spinal fixation surgery for osteoporotic vertebral collapse (OVC) with neurological deficits. This study aimed to identify the incidence and risk factors of the complications after OVC surgery. METHODS: In this retrospective multicenter study, a total of 403 patients (314 women and 89 men; mean age 73.8 years) who underwent spinal fixation surgery for OVC with neurological deficits between 2005 and 2014 were enrolled. Data on patient demographics were collected, including age, sex, body mass index, smoking, steroid use, medical comorbidities, and surgical procedures. All postoperative complications that occurred within 6 weeks were recorded. Patients were classified into two groups, namely, complication group and no complication group, and risk factors for postoperative complications were investigated by univariate and multivariate analyses. RESULTS: Postoperative complications occurred in 57 patients (14.1%), and the most common complication was delirium (5.7%). In the univariate analysis, the complication group was found to be older (p = 0.039) and predominantly male (p = 0.049), with higher occurrence rate of liver disease (p = 0.001) and Parkinson's disease (p = 0.039) compared with the no-complication group. In the multivariate analysis, the significant independent risk factors were age (p = 0.021; odds ratio [OR] 1.051, 95% confidence interval [CI] 1.007-1.097), liver disease (p < 0.001; OR 8.993, 95% CI 2.882-28.065), and Parkinson's disease (p = 0.009; OR 3.636, 95% CI 1.378-9.599). CONCLUSIONS: Complications after spinal fixation surgery for OVC with neurological deficits occurred in 14.1%. Age, liver disease, and Parkinson's disease were demonstrated to be independent risk factors for postoperative complications.

Conventional JOA score for cervical myelopathy has a rater's bias -In comparison with JOACMEQ.

BACKGROUND: The JOA (Japan Orthopaedic Association) score has been a standard outcome measure to evaluate cervical myelopathy in Japan. Despite its reliability and convenience, there can be a rating bias in the JOA score. The current study was conducted to delineate the rater's bias of the JOA score by comparing it with a new objective outcome measure. METHODS: Two hundred and thirty four operative candidates with cervical myelopathy were included in the study. The patients were divided into four groups according to the surgeon (92 patients in group A, 60 patients in group B, 38 patients in group C and 44 patients in group D). Each patient's preoperative JOA score was exclusively recorded by the surgeon himself, while JOACMEQ (Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire) was recorded by each patient. Disease severity, the most important prognostic factor, was equalized between patient groups by a special statistical method called inverse-probability weighting (IPW). To define similarity of the two groups, Cohen's d was used. RESULTS: After the adjustment, the differences of the JOA score were only 0.1 between groups A and D and 0 between groups B and C. The values of Cohen's d were also very small both between groups A and D (3%), and between groups B and C (0.3%). The averaged JOA scores of groups A and D were higher by 0.4-0.8 than those of groups B and C, while the averaged JOA scores were almost the same both between groups A and D, and between groups B and C. Surgeons A and D had the same tendency to give higher JOA scores than surgeons B and C did. CONCLUSIONS: The current study confirmed there is a definite rater's bias in the JOA score. JOACMEQ is to be applied as a more reliable outcome measure to evaluate myelopathy patients.

Hounsfield unit of screw trajectory as a predictor of pedicle screw loosening after single level lumbar interbody fusion.

OBJECT: This study aims to clarify the clinical potential of Hounsfield unit (HU), measured on computed tomography (CT) images, as a predictor of pedicle screw (PS) loosening, compared to bone mineral density (BMD). METHODS: A total of 206 screws in 52 patients (21 men and 31 women; mean age 68.2 years) were analyzed retrospectively. The screws were classified into two groups depending on their screw loosening status on 3-month follow-up CT (loosening screw group vs. non-loosening screw group). Preoperative HU of the trajectory was evaluated by superimposing preoperative and postoperative CT images using three-dimensional image analysis software. Age, sex, body mass index, screw size, BMD of lumbar, and HU of screw trajectory were analyzed in association with screw loosening. Multivariate logistic regression analysis was performed, and the thresholds for PS loosening risk factors were evaluated using a continuous numerical variable and receiver operating characteristic (ROC) curve analyses. The area under the curve (AUC) was used to determine the diagnostic performance, and values > 0.75 were considered to represent good performance. RESULTS: The loosening screw group contained 24 screws (12%). Multivariate analysis revealed that the significant independent risk factors were not BMD but male sex [P = 0.028; odds ratio (OR) 2.852, 95% confidence interval (CI) 1.120-7.258] and HU of screw trajectory (P = 0.006; OR 0.989, 95% CI 0.980-0.997). ROC curve analysis demonstrated that the AUC for HU of screw trajectory for women was 0.880 (95% CI 0.798-0.961). The cutoff value was 153.5. AUC for men was 0.635 (95% CI 0.449-0.821), which was not considered to be a good performance. CONCLUSIONS: Low HU of screw trajectories was identified as a risk factor of PS loosening for women. For female patients with low HU, additional augmentation is recommended to prevent PS loosening.

Difference in the fusion rate and bone formation between artificial bone and iliac autograft inside an inter-body fusion cage - A comparison between porous hydroxyapatite/type 1 collagen composite and autologous iliac bone.

BACKGROUND: Lateral inter-body fusion (LIF) using cages with a large bone grafting space can lead to a shortage of autologous grafting materials. The use of artificial bone is an option to increase the volume of grafting materials. However, the rate of bony fusion for these materials compared to that of autologous bone is unclear. METHODS: The bone fusion rate for artificial bone (HAp/Col) and autologous iliac bone (IBG) graft among 23 patients who had undergone LIF (total 66 disc levels) combined with multilevel posterior corrective fusion for the treatment of adult spinal deformity was retrospectively evaluated. To allow comparison, one of the two separate bone grafting holes in each LIF cage was filled with HAp/Col and the other, with IBG. The change in Hounsfield units (HU) inside the implanted holes at 1-year post surgery (PO1Y) from baseline and immediately after surgery and bony fusion between adjacent vertebrae, defined by the extent of trabecular continuity at PO1Y, were evaluated using computed tomography. Differences between the convex and concave sides as well as effects of the side of approach were investigated. RESULTS: HU values increased significantly for IBG, from 228.9 at baseline to 286.1 at PO1Y (p < 0.001), with no change for HAp/Col. The fusion rate was higher for IBG (71.2%) than for HAp/Col (19.7%; p < 0.001). A significant effect of the location of the holes on fusion rate was identified for HAp/Col but not IBG. No effects of the side of approach were identified. CONCLUSIONS: A higher rate of fusion in LIF cages was obtained with IBG than with HAp/Col, with no effect of location of implantation (convex or concave) for IBG. Therefore, exclusive use of artificial bone, particularly on the convex side, should be avoided during LIF.

Prediction of Postoperative Clinical Recovery of Drop Foot Attributable to Lumbar Degenerative Diseases, via a Bayesian Network.

BACKGROUND: Drop foot resulting from degenerative lumbar diseases can impair activities of daily living. Therefore, predictors of recovery of this symptom have been investigated using univariate or/and multivariate analyses. However, the conclusions have been somewhat controversial. Bayesian network models, which are graphic and intuitive to the clinician, may facilitate understanding of the prognosis of drop foot resulting from degenerative lumbar diseases. QUESTIONS/PURPOSES: (1) To show a layered correlation among predictors of recovery from drop foot resulting from degenerative lumbar diseases; and (2) to develop support tools for clinical decisions to treat drop foot resulting from lumbar degenerative diseases. METHODS: Between 1993 and 2013, we treated 141 patients with decompressive lumbar spine surgery who presented with drop foot attributable to degenerative diseases. Of those, 102 (72%) were included in this retrospective study because they had drop foot of recent development and had no diseases develop that affect evaluation of drop foot after surgery. Specifically, 28 (20%) patients could not be analyzed because their records were not available at a minimum of 2 years followup after surgery and 11 (8%) were lost owing to postoperative conditions that affect the muscle strength evaluation. Eight candidate variables were sex, age, herniated soft disc, duration of the neurologic injury (duration), preoperative tibialis anterior muscle strength (pretibialis anterior), leg pain, cauda equina syndrome, and number of involved levels. Manual muscle testing was used to assess the tibialis anterior muscle strength. Drop foot was defined as a tibialis anterior muscle strength score of less than 3 of 5 (5 = movement against gravity and full resistance, 4 = movement against gravity and moderate resistance, 3 = movement against gravity through full ROM, 3- = movement against gravity through partial ROM, 2 = movement with gravity eliminated through full ROM, 1 = slight contraction but no movement, and 0 = no contraction). The two outcomes of interest were postoperative tibialis anterior muscle strength (posttibialis anterior) of 3 or greater and posttibialis anterior strength of 4 or greater at 2 years after surgery. We developed two separate Bayesian network models with outcomes of interest for posttibialis anterior strength of 3 or greater and posttibialis anterior strength of 4 or greater. The two outcomes correspond to "good" and "excellent" results based on previous reports, respectively. Direct predictors are defined as variables that have the tail of the arrow connecting the outcome of interest, whereas indirect predictors are defined as variables that have the tail of the arrow connecting either direct predictors or other indirect predictors that have the tail of the arrow connecting direct predictors. Sevenfold cross validation and receiver-operating characteristic (ROC) curve analyses were performed to evaluate the accuracy and robustness of the Bayesian network models. RESULTS: Both of our Bayesian network models showed that weaker muscle power before surgery (pretibialis anterior ≤ 1) and longer duration of neurologic injury before treatment (> 30 days) were associated with a decreased likelihood of return of function by 2 years. The models for posttibialis anterior muscle strength of 3 or greater and posttibialis anterior muscle strength of 4 or greater were the same in terms of the graphs, showing that the two direct predictors were pretibialis anterior muscle strength (score ≤ 1 or ≥ 2) and duration (≤ 30 days or > 30 days). Age, herniated soft disc, and leg pain were identified as indirect predictors. We developed a decision-support tool in which the clinician can enter pretibialis anterior muscle strength and duration, and from this obtain the probability estimates of posttibialis anterior muscle strength. The probability estimates of posttibialis anterior muscle strength of 3 or greater and posttibialis anterior muscle strength of 4 or greater were 94% and 85%, respectively, in the most-favorable conditions (pretibialis anterior ≥ 2; duration ≤ 30 days) and 18% and 14%, respectively, in the least-favorable conditions (pretibialis anterior ≤ 1; duration > 30 days). On the sevenfold cross validation, the area under the ROC curve yielded means of 0.78 (95% CI, 0.68-0.87) and 0.74 (95% CI, 0.64-0.84) for posttibialis anterior muscle strength of 3 or greater and posttibialis anterior muscle strength of 4 or greater, respectively. CONCLUSIONS: The results of this study suggest that the clinician can understand intuitively the layered correlation among predictors by Bayesian network models. Based on the models, the decision-support tool successfully provided the probability estimates of posttibialis anterior muscle strength to treat drop foot attributable to lumbar degenerative diseases. These models were shown to be robust on the internal validation but should be externally validated in other populations. LEVEL OF EVIDENCE: Level III, therapeutic study.

Differences in vertebral morphology around the apical vertebrae between neuromuscular scoliosis and idiopathic scoliosis in skeletally immature patients: a three-dimensional morphometric analysis.

BACKGROUND: Recent morphological analyses of vertebrae in patients with scoliosis have revealed three-dimensional (3D) deformities in the vertebral bodies. However, it remains controversial whether these deformities are secondary changes caused by asymmetrical vertebral loading or primary changes caused by aberrant asymmetrical vertebral growth. Furthermore, the difference in vertebral morphology between scoliosis with different pathogeneses remains unclear. This study was aimed to investigate the difference in the coronal asymmetry of vertebral bodies between neuromuscular scoliosis (NS) in Duchenne muscular dystrophy (DMD) and idiopathic scoliosis (IS) using in vivo 3D analysis. METHODS: Twelve male skeletally immature patients with NS in DMD and 13 female skeletally immature patients with IS who underwent corrective fusion at our institution were included retrospectively. 3D bone models of the apical and adjacent upper and lower vertebrae in the major curve in the NS patients and in the main and compensatory curves in the IS patients were constructed using an image processing workstation. The heights of the concave and convex sides of the vertebral bodies were measured at the anterior, middle, and posterior and the concave-to-convex vertebral height ratios (VHR) were calculated. RESULTS: The mean VHRs (anterior/middle/posterior) for the main curve for IS (0.897 ± 0.072/0.832 ± 0.086/0.883 ± 0.059) were significantly smaller than those for NS (0.970 ± 0.048/0.934 ± 0.081/0.958 ± 0.043) in all three parts (p < 0.001). Those of the compensatory curve in IS (0.968 ± 0.045/0.942 ± 0.067/0.967 ± 0.046) did not differ significantly from the NS values in any part. CONCLUSIONS: When compared to the wedging of the vertebral bodies around apical vertebrae in the major curve in NS, which was caused by asymmetric loading, the wedge deformities in both the main and compensatory curves in IS were more severe than would be expected. Our results indicated that morphometric characteristics of vertebral bodies differed according to the pathogenesis of scoliosis and that the pathology of the wedging of vertebral bodies in IS could not be a result only of asymmetric loading to the vertebral bodies.

Plasticity of vertebral wedge deformities in skeletally immature patients with adolescent idiopathic scoliosis after posterior corrective surgery.

BACKGROUND: Vertebral bodies in patients with adolescent idiopathic scoliosis (AIS) usually have frontal wedge deformities. However, the plasticity of the deformed vertebrae in skeletally immature patients is unknown. The purpose of our study was to clarify the plasticity of vertebral deformities in skeletally immature patients with AIS by using in vivo three-dimensional (3D) analysis. METHODS: Ten female patients with AIS (mean age, 12.2 years; three patients, Lenke type 1; five patients, type 2; two patients, type 5) who underwent posterior fusion and whose Risser grade was ≤3 at surgery were included. Using computed tomography images (0.625-mm slice thickness) obtained 1 week and 1 year postoperatively, a total of seventy-three 3D bone models of vertebrae was made. The 3D bone models were made between the upper and lower end vertebrae within the main thoracic curve for patients with Lenke types 1 and 2 scoliosis, whereas they were made within the thoracolumbar/lumbar curve in patients with Lenke type 5 scoliosis. The height of the concave and convex sides in the anterior, middle and posterior parts of the vertebral bodies was measured using the original digital viewer, and the vertebral height ratio (VHR: concave/convex) was calculated. VHRs at 1 week and 1 year postoperatively were compared using the Wilcoxson signed-rank test. Differences were considered statistically significant at p < 0.05. RESULTS: VHR of the end vertebrae (n = 20) did not change postoperatively for any parts of the vertebral bodies. VHR of the vertebrae in the apical region (n = 28) also remained unchanged postoperatively. In contrast, VHR of the other vertebrae (n = 25) increased significantly in the anterior part postoperatively (from 0.938 to 0.961, p = 0.006). CONCLUSIONS: The wedge deformity of vertebral bodies showed a reshaping potential towards a symmetrical configuration in the region other than end and apex, although no plasticity of the vertebrae was observed in the apical region even in skeletally immature patients with AIS.

Surgical outcomes for painless drop foot due to degenerative lumbar disorders.

STUDY DESIGN: Twenty patients presenting with painless drop foot who had undergone lumbar spine surgery for degenerative lumbar diseases were included in this retrospective study. OBJECTIVE: This study aims to investigate which causative factors and patient symptoms significantly affected surgical outcome. SUMMARY OF BACKGROUND DATA: Drop foot is a neuromuscular condition that results in dorsiflexion palsy of the ankle. Patients with drop foot often complain of leg pain. Rarely, patients experience painless drop foot due to lumbar degenerative disease. For these patients, the only purpose of surgery is to improve the palsy; this makes it difficult to determine whether surgical intervention is indicated. No studies have focused on the results of surgical treatment for painless drop foot caused by degenerative lumbar diseases. METHODS: Preoperative strength of the tibialis anterior and duration of palsy were recorded and considered with surgical outcome. RESULTS: Sixty-five percent of patients recovered from drop foot after surgery. Drop foot was caused mainly by impairment of the L5 nerve root. Patients with a longer duration of palsy had poorer results. CONCLUSIONS: Duration of palsy had the greatest effect on recovery. As the only goal of this surgery is improvement in the strength of the tibialis anterior, caution must be exercised when considering surgery for patients with longstanding palsy.

Neurological manifestations of thoracic myelopathy.

INTRODUCTION: Investigation of preoperative manifestations of thoracic myelopathy in a large population has not been reported. The aim of this study was to identify symptoms specific to anatomical pathology or compressed segments in thoracic myelopathy through investigation of preoperative manifestations. MATERIALS AND METHODS: Subjects were 205 patients [143 men, 62 women; mean age, 62.2 (range 21-87 years)] with thoracic myelopathy who underwent surgery at our affiliate institutions from 2000 to 2011. The disease distribution included ossification of the ligamentum flavum (OLF) in 106 patients, ossification of the posterior longitudinal ligament (OPLL) in 17, OLF with OPLL in 17, intervertebral disc herniation (IDH) in 23, OLF with IDH in 3, and spondylosis in 39. We assessed (1) initial and preoperative complaints, (2) neurological findings, (3) Japanese Orthopaedic Association scores (JOA, full score, 11 points), (4) the compressed segments, and (5) preoperative duration. Multivariate analyses were performed to examine potential relationships between preoperative manifestations and anatomical pathology or compressed segments. RESULTS: The multivariate analyses revealed relationships between lower limb muscle weakness and T10/11 anterior compression; lower limb pain and T11/12 anterior compression; low back pain and T11/12 compression; and hyporeflexia in the patellar tendon reflex/foot drop and T12/L1 anterior compression. CONCLUSION: This study elucidated symptoms specific to anatomical pathology or compressed segments in thoracic myelopathy. These relationships can be helpful in the initial investigation of thoracic diseases, although additional measures such as MRI or CT are necessary for definitive diagnosis.

Risk Factor Analysis of Surgery-related Complications in Primary Thoracic Spine Surgery for Degenerative Diseases and Characteristics of the Patients Also Undergoing Surgery on the Cervical and/or Lumbar Spine.

STUDY DESIGN: A retrospective cohort study using prospectively collected data. OBJECTIVE: This study primarily aimed to investigate the risk factors for surgery-related complications in primary thoracic spine surgery for degenerative diseases using a surgeon-maintained database. The secondary purpose was to elucidate the characteristics of surgically treated thoracic myelopathy that also required cervical and/or lumbar spine surgery in the study period. SUMMARY OF BACKGROUND DATA: Few studies reported surgical complications and the feature of tandem spinal stenosis in thoracic myelopathy in detail because of their rarity. MATERIALS AND METHODS: This study included 840 thoracic myelopathy patients undergoing primary surgery for degenerative diseases from 2012 to 2021, investigating the effects of diseases, surgical procedures, and patient demographics on postoperative neurological deterioration, dural tear, dural leakage, surgical-site infection, and postoperative hematoma. In thoracic myelopathy patients who were surgically treated and also undergoing cervical and/or lumbar surgery, we investigated the proportion, the effects of diseases, and the order and intervals between surgeries. RESULTS: Multivariate logistic regression revealed that significant risk factors ( P <0.05) for postoperative neurological deterioration were intervertebral disk herniation [odds ratio (OR): 4.59, 95% confidence interval (CI): 1.32-16.0) and degenerative spondylolisthesis (OR: 11.1, 95% CI: 2.15-57.5). Ossification of the ligamentum flavum (OR: 4.12, 95% CI: 1.92-8.86), anterior spinal fusion (OR: 41.2, 95% CI: 4.70-361), and circumferential decompression via a posterior approach (OR: 30.5, 95% CI: 2.27-410) were risk factors for dural tear. In thoracic myelopathy patients surgically treated, 37.0% also underwent degenerative cervical and/or lumbar surgery. CONCLUSIONS: Pathologies involving anterior decompression and instability increased the risk of postoperative neurological deterioration. The risk of dural tear was increased when dura mater adhesions were likely to be directly operated upon. It should be recognized that a relatively high proportion (37.0%) of surgically treated thoracic myelopathy patients also underwent cervical and/or lumbar surgery.

An 88-Year-Old Woman With Pneumothorax and Black Pleural Effusion.

CASE PRESENTATION: An 88-year-old woman was admitted to our hospital with the sudden onset of dyspnea after eating. The patient had undergone nephrectomy for a left renal tumor 24 years previously. The patient had been prescribed ferrous citrate for iron-deficiency anemia. She complained of appetite loss a few days before admission but had no abdominal pain. CT scan showed no abnormalities in the lungs but a mass in the liver.

Appropriate pelvic obliquity measurement method in Lenke type 5C adolescent idiopathic scoliosis: a preliminary study.

Background: Although pelvic obliquity (PO) is a risk factor for postoperative coronal decompensation in corrective surgery in adolescent idiopathic scoliosis (AIS), especially Lenke 5C, methods of measuring PO are controversial. This study aimed to establish an appropriate measurement method using multiplanar reconstructed computed tomography (MPR-CT) images instead of standing posteroanterior (PA) whole-spine radiographs to evaluate PO in patients with Lenke 5C AIS. Methods: This study was a retrospective cross-sectional study. Twenty-five patients who underwent corrective surgery for AIS in Osaka University Hospital from August 2014 to February 2023 were included. Cobb angle, L5 tilt, C7 plumb line to center sacral vertebral line (C7PL-CSVL), and leg length discrepancy (LLD) were measured on standing PA whole-spine radiographs preoperatively. Sacral obliquity (SO), the slope of the upper endplate of S1, and iliac obliquity (IO), the tilt of the line connecting the iliac crests, were measured on standing PA whole-spine radiographs and MPR-CT (SO/IO-X-ray, SO/IO-CT, respectively). S1 angle and S2 angle were measured on CT. Results: The mean age of the patients was 18.7±3.9 years and all of them were females. SO-X-ray and SO-CT were larger than IO-X-ray and IO-CT, respectively. SO-X-ray was highly correlated with SO-CT (r=0.838, P<0.001). L5 tilt had higher correlation with SO-CT (r=0.884, P<0.001) than with SO-X-ray (r=0.726, P=0.001) and IO-CT (r=0.550, P=0.22). L5 tilt was correlated poorly with IO-X-ray (r=0.104, P=0.69). The S1 angle was 4.5±3.5° meanwhile the S2 angle was 1.2±2.1°, the sacral deformity was mainly due to the S1 vertebral wedging. Conclusions: Given the asymmetric sacral morphology, SO is more appropriate pelvic parameter than IO to represent the sacral tilt of Lenke 5C AIS, especially when measured using CT images to overcome the poor visibility on PA whole-spine radiographs.

Development of patient-reported outcome for adult spinal deformity: validation study.

Adult spinal deformity (ASD) is a complex condition that combines scoliosis, kyphosis, pain, and postoperative range of motion limitation. The lack of a scale that can successfully capture this complex condition is a clinical challenge. We aimed to develop a disease-specific scale for ASD. The study included 106 patients (mean age; 68 years, 89 women) with ASD. We selected 29 questions that could be useful in assessing ASD and asked the patients to answer them. The factor analysis found two factors: the main symptom and the collateral symptom. The main symptom consisted of 10 questions and assessed activity of daily living (ADL), pain, and appearance. The collateral symptom consisted of five questions to assess ADL due to range of motion limitation. Cronbach's alpha was 0.90 and 0.84, respectively. The Spearman's correlation coefficient between the change of main symptom and satisfaction was 0.48 (p < 0.001). The effect size of Cohen's d for comparison between preoperative and postoperative scores was 1.09 in the main symptom and 0.65 in the collateral symptom. In conclusion, we have developed a validated disease-specific scale for ASD that can simultaneously evaluate the benefits and limitations of ASD surgery with enough responsiveness in clinical practice.

Automated entry of paper-based patient-reported outcomes: Applying deep learning to the Japanese orthopaedic association back pain evaluation questionnaire.

BACKGROUND: Health-related patient-reported outcomes (HR-PROs) are crucial for assessing the quality of life among individuals experiencing low back pain. However, manual data entry from paper forms, while convenient for patients, imposes a considerable tallying burden on collectors. In this study, we developed a deep learning (DL) model capable of automatically reading these paper forms. METHODS: We employed the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire, a globally recognized assessment tool for low back pain. The questionnaire comprised 25 low back pain-related multiple-choice questions and three pain-related visual analog scales (VASs). We collected 1305 forms from an academic medical center as the training set, and 483 forms from a community medical center as the test set. The performance of our DL model for multiple-choice questions was evaluated using accuracy as a categorical classification task. The performance for VASs was evaluated using the correlation coefficient and absolute error as regression tasks. RESULT: In external validation, the mean accuracy of the categorical questions was 0.997. When outputs for categorical questions with low probability (threshold: 0.9996) were excluded, the accuracy reached 1.000 for the remaining 65 % of questions. Regarding the VASs, the average of the correlation coefficients was 0.989, with the mean absolute error being 0.25. CONCLUSION: Our DL model demonstrated remarkable accuracy and correlation coefficients when automatic reading paper-based HR-PROs during external validation.

Multimodal Deep Learning-based Radiomics Approach for Predicting Surgical Outcomes in Patients with Cervical Ossification of the Posterior Longitudinal Ligament.

STUDY DESIGN: A retrospective analysis. OBJECTIVE: This research sought to develop a predictive model for surgical outcomes in patients with cervical ossification of the posterior longitudinal ligament (OPLL) using deep learning and machine learning (ML) techniques. SUMMARY OF BACKGROUND DATA: Determining surgical outcomes assists surgeons in communicating prognosis to patients and setting their expectations. Deep learning and ML are computational models that identify patterns from large datasets and make predictions. METHODS: Of the 482 patients, 288 patients were included in the analysis. A minimal clinically important difference (MCID) was defined as gain in Japanese Orthopaedic Association (JOA) score of 2.5 points or more. The predictive model for MCID achievement at 1 year post-surgery was constructed using patient background, clinical symptoms, and preoperative imaging features (x-ray, CT, MRI) analyzed via LightGBM and deep learning with RadImagenet. RESULTS: The median preoperative JOA score was 11.0 (IQR: 9.0-12.0), which significantly improved to 14.0 (IQR: 12.0-15.0) at 1 year after surgery (P < 0.001, Wilcoxon signed-rank test). The average improvement rate of the JOA score was 44.7%, and 60.1% of patients achieved the MCID. Our model exhibited an area under the receiver operating characteristic curve of 0.81 and the accuracy of 71.9% in predicting MCID at 1 year. Preoperative JOA score and certain preoperative imaging features were identified as the most significant factors in the predictive models. CONCLUSION: A predictive ML and deep learning model for surgical outcomes in OPLL patients is feasible, suggesting promising applications in spinal surgery. LEVEL OF EVIDENCE: 4.