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Introduction: For older adults, dysphagia is a serious problem that can occur after spinal cord injury (SCI), but its risk factors are unclear. This study aimed to identify risk factors for dysphagia in elderly patients (65 years) with cervical SCI. Methods: This multicenter study included 707 patients with cervical SCI (mean age 75.3 years). Univariate and multivariate analyses were conducted for patient characteristics and geriatric nutritional risk index (GNRI). Results: Dysphagia occurred in 69 patients (9.8%). The significant factors were as follows: male sex (odds ratio [OR] 3.43), GNRI

Introduction: Human pose estimation, a computer vision technique that identifies body parts and constructs human body representations from images and videos, has recently demonstrated high performance through deep learning. However, its potential application in clinical photography remains underexplored. This study aimed to establish photographic parameters for patients with adolescent idiopathic scoliosis (AIS) using pose estimation and to determine correlations between these photographic parameters and corresponding radiographic measures. Methods: We conducted a study involving 42 patients with AIS who had undergone spinal correction surgery and conservative treatment. Preoperative photographs were captured using an iPhone 13 Pro mounted on a tripod positioned at the head of an X-ray tube. From the outputs of pose estimation, we derived five photographic parameters and subsequently conducted a statistical analysis to assess their correlations with relevant conventional radiographic parameters. Results: In the sagittal plane, we identified significant correlations between photographic and radiographic parameters measuring trunk tilt angles. In the coronal plane, significant correlations were found between photographic parameters measuring shoulder height and trunk tilt and corresponding radiographic measurements. Conclusions: The results suggest that pose estimation, achievable with common mobile devices, offers potential for AIS screening, early detection, and continuous posture monitoring, effectively mitigating the need for X-ray radiation exposure. Level of Evidence: 3.

Abstract This retrospective cohort study established malnutrition’s impact on mortality and neurological recovery of older patients with cervical spinal cord injury (SCI). It included patients aged ≥ 65 years with traumatic cervical SCI treated conservatively or surgically. The Geriatric Nutritional Risk Index was calculated to assess nutritional-related risk. Overall, 789 patients (mean follow-up: 20.1 months) were examined and 47 had major nutritional-related risks on admission. One-year mortality rate, median survival time, neurological recovery, and activities of daily living (ADL) at 1 year post-injury were compared between patients with major nutrition-related risk and matched controls selected using 1:2 propensity score matching to adjust for age, pre-traumatic neurological impairment, and activity. In the Kaplan–Meier analysis, the median survival times were 44.9 and 76.5 months for patients with major nutrition-related risk and matched controls, respectively (p = 0.015). Matched controls had more individuals with a neurological improvement of American Spinal Injury Association Impairment Scale ≥ 1 grade (p = 0.039) and independence in ADL at 1 year post-injury than patients with major nutrition-related risk (p

Abstract Although the incidence of cervical spinal cord injury (CSCI) with ossification of the posterior longitudinal ligament (OPLL) has increased in older adults, its etiology and neurological outcomes remain unknown. We identified OPLL characteristics and determined whether they influence neurological severity and improvement of CSCI in older patients. This multicenter retrospective cohort study identified 1512 patients aged ≥ 65 years diagnosed with CSCI on admission during 2010–2020. We analyzed CSCI etiology in OPLL patients. We performed propensity score-adjusted analyses to compare neurological outcomes between patients with and without OPLL. Cases were matched based on variables influencing neurological prognosis. The primary neurological outcome was rated according to the American Spine Injury Association (ASIA) impairment scale (AIS) and ASIA motor score (AMS). In 332 OPLL patients, the male-to-female ratio was approximately 4:1. Half of all patients displayed low-energy trauma-induced injury and one-third had CSCI without a bony injury. Propensity score matching created 279 pairs. There was no significant difference in the AIS grade and AMS between patients with and without OPLL during hospitalization, 6 months, and 12 months following injury. OPLL patients tended to exhibit worse neurological findings during injury; nevertheless, OPLL was not associated with poor neurological improvement in older CSCI patients.

Abstract No validated systems exist for selecting the upper instrumented vertebra (UIV) for optimal postoperative shoulder balance in Lenke type 2 adolescent idiopathic scoliosis (AIS). This study evaluated a new method for shoulder balance prediction using the modified Shinshu line (MSL) for UIV selection in AIS Lenke type 2 curves. Fifty-five consecutive AIS patients receiving posterior spinal fusion (PSF) for a Lenke type 2 AIS curve were retrospectively analyzed according to several UIV determination models. Shoulder imbalance was judged as absolute radiographic shoulder height ≥ 10 mm at the 2-year observational endpoint. The MSL was the line between the center of the spinous process of C7 and that of the lowest instrumented vertebra. The vertebral body first touched proximally by the MSL was defined as the MSL vertebra (MSLV) and recommended as the UIV. The group with the UIV matching the MSLV had a significantly lower prevalence of shoulder imbalance of 23% (odds ratio 4.08, 95% CI 1.22–13.7, P = 0.02). Setting the MSLV as the UIV in PSF for AIS Lenke type 2 may reduce the prevalence of postoperative shoulder imbalance.

Abstract Although traumatic cervical spine injuries in older adults are commonly caused by minor traumas, such as ground-level falls, their prognosis is often unfavorable. Studies examining the clinical characteristics of cervical spine injuries in older adults according to the external cause of injury are lacking. This study included 1512 patients of ≥ 65 years of age with traumatic cervical spine injuries registered in a Japanese nationwide multicenter database. The relationship between the external causes and clinical characteristics, as well as factors causing unfavorable outcomes at the ground-level falls, were retrospectively reviewed and examined. When fall-induced cervical spine injuries were categorized and compared based on fall height, the patients’ backgrounds and injury statuses differed significantly. Of note, patients injured from ground-level falls tended to have poorer pre-injury health conditions, such as medical comorbidities and frailty, compared with those who fell from higher heights. For ground-level falls, the mortality, walking independence, and home-discharge rates at 6 months post-injury were 9%, 67%, and 80%, respectively, with preexisting medical comorbidities and frailty associated with unfavorable outcomes, independent of age or severity of neurological impairment at the time of injury.

Introduction: In elderly patients with cervical spinal cord injury, comorbidities such as cardiovascular and cerebrovascular diseases are common, with frequent administration of antiplatelet/anticoagulant (APAC) drugs. Such patients may bleed easily or unexpectedly during surgery despite prior withdrawal of APAC medication. Few reports have examined the precise relationship between intraoperative blood loss and history of APAC use regarding surgery for cervical spine injury in the elderly. The present multicenter database survey aimed to answer the question of whether the use of APAC drugs affected the amount of intraoperative blood loss in elderly patients with cervical spinal cord trauma. Methods: The case histories of 1512 patients with cervical spine injury at 33 institutes were retrospectively reviewed. After excluding cases without spinal surgery or known blood loss volume, 797 patients were enrolled. Blood volume loss was the outcome of interest. We calculated propensity scores using the inverse probability of treatment weighting (IPTW) method. As an alternative sensitivity analysis, linear mixed model analyses were conducted as well. Results: Of the 776 patients (mean age: 75.1±6.4 years) eligible for IPTW calculation, 157 (20.2%) were taking APAC medications before the injury. After weighting, mean estimated blood loss was 204 mL for non-APAC patients and 215 mL for APAC patients. APAC use in elderly patients was not significantly associated with surgical blood loss according to the IPTW method with propensity scoring or linear mixed model analyses. Thus, it appeared possible to perform surgery expecting comparable blood loss in APAC and non-APAC cases. Conclusions: This multicenter study revealed no significant increase in surgical blood loss in elderly patients with cervical trauma taking APAC drugs. Surgeons may be able to prioritize patient background, complications, and preexisting conditions over APAC use before injury when examining the surgical indications for cervical spine trauma in the elderly.

Abstract Positive association between ossification of the posterior longitudinal ligament of the spine (OPLL) and obesity is widely recognized; however, few studies focused on the effects of obesity on treatment of cervical OPLL. The effects of obesity on surgical treatment of cervical OPLL were investigated by a Japanese nationwide, prospective study. Overall, 478 patients with cervical myelopathy due to OPLL were prospectively enrolled. To clarify the effects of obesity on the surgical treatment for cervical OPLL, patients were stratified into two groups, non-obese (

Abstract This prospective multicenter study, established by the Japanese Ministry of Health, Labour and Welfare and involving 27 institutions, aimed to compare postoperative outcomes between laminoplasty (LM) and posterior fusion (PF) for cervical ossification of the posterior longitudinal ligament (OPLL), in order to address the controversy surrounding the role of instrumented fusion in cases of posterior surgical decompression for OPLL. 478 patients were considered for participation in the study; from among them, 189 (137 and 52 patients with LM and PF, respectively) were included and evaluated using the Japanese Orthopaedic Association (JOA) scores, the JOA Cervical Myelopathy Evaluation Questionnaire (JOACMEQ), and radiographical measurements. Basic demographic and radiographical data were reviewed, and the propensity to choose a surgical procedure was calculated. Preoperatively, there were no significant differences among the participants in terms of patient backgrounds, radiographical measurements (K-line or cervical alignment on X-ray, OPLL occupation ratio on computed tomography, increased signal intensity change on magnetic resonance imaging), or clinical status (JOA score and JOACMEQ) after adjustments. The overall risk of perioperative complications was found to be lower with LM (odds ratio [OR] 0.40, p = 0.006), and the rate of C5 palsy occurrence was significantly lower with LM (OR 0.11, p = 0.0002) than with PF. The range of motion (20.91° ± 1.05° and 9.38° ± 1.24°, p

Introduction: Assessments of early postoperative bony union after posterior lumbar interbody fusion via computed tomography (CT) have revealed cases in which interbody fixation by bony union resulted in nonfusion due to bone absorption. The apparent bone union state reverted to a nonunion state several months later, exhibiting a so-called “fake union” phenomenon. Additionally, few reports have evaluated the effect of teriparatide on bony union. The present study aimed to evaluate the frequency of change in assessment from fusion to nonfusion in the postoperative follow-up of lumbar interbody fusion, compare the late postoperative bony union rates in groups with or without early postoperative fusion, and examine the effect of postoperative teriparatide in those groups. Methods: Sixty-nine subjects enrolled from multiple hospitals were prospectively evaluated following single-level lumbar interbody fusion. The patients were randomly allocated into treatment with or without weekly postoperative teriparatide. The subjects were then classified as having bony union or nonfusion at 2 months postoperatively, and fusion rates at 6 months were compared. For the evaluation of bony union, blinded radiological examinations were performed via CT. Additional comparisons were made according to teriparatide use. Results: The rate of nonunion at 6 months postoperatively in patients with fusion at 2 months postoperatively was 27.8%. Among subjects with bony union at 2 months postoperatively, the fusion rate at 6 months in those who received teriparatide was 93.3% (p=0.027) versus 57.1% in those who did not. Conclusions: The rate of nonunion at 6 months postoperatively in patients exhibiting union at 2 months after surgery was 27.8%. Postoperative weekly teriparatide treatment significantly reduced the rate of fake union.

Abstract Ossification of the posterior longitudinal ligament (OPLL) is a progressive disease. The bridging of ossified lesions to the vertebral body gradually increases, thereby decreasing the mobility of the cervical spine; thus, cervical spine function may decrease over time. However, cervical spine function in patients with cervical OPLL has not been evaluated in large prospective studies. Therefore, we conducted a prospective multicenter study to clarify whether ossification spread can influence cervical spine function and quality of life (QOL) in patients with cervical OPLL. In total, 238 patients (162 men, 76 women; mean age, 63.9 years) were enrolled from 16 institutions. Each patient underwent whole spine computed tomography and was evaluated for cervical spine function and QOL using the Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ). In the multivariate regression analysis, a higher neck VAS score and a larger number of bridge formations of OPLL in the whole spine were significant predictors of adverse outcomes related to cervical spine function. This is the first prospective multicenter study to reveal the impact of ossification spread on cervical spine function. These findings are important to understand the natural course of OPLL and can serve as controls when evaluating postoperative cervical spine function.

Abstract Although favourable surgical outcomes for myelopathy caused by cervical ossification of the posterior longitudinal ligament (OPLL) have been reported, factors significantly associated with post-operative neck pain attenuation still remain unclear. The primary aim of the present study was to determine factors significantly associated with post-operative neck pain attenuation in patients with cervical OPLL using a prospective multi-centre registry of surgically treated cervical OPLL. Significant postoperative neck pain reduction (50% reduction of neck pain) was achieved in 31.3% of patients. There was no significant difference in neck pain attenuation between surgical procedures. Statistical analyses with univariate analyses followed by stepwise logistic regression revealed neurological recovery as a factor having a significant positive association with post-operative neck pain attenuation (p = 0.04, odds ratio 5.68 (95% confidence interval: 1.27–22.2)). In conclusion, neurological recovery was an independent factor having a significant positive association with post-operative neck pain attenuation in patients with cervical myelopathy caused by OPLL who underwent cervical spine surgery.

Introduction: Postoperative respiratory complications (PRC) are one of the most serious complications. Potentially life-threatening accidents can occur after an anterior cervical discectomy and fusion (ADF), such as airway obstruction and aspiration pneumonia. Despite numerous studies, preoperative predictive and preventive methodology has yet to be established. As reported in our previous study, the evaluation of preoperative dysphagia using the eating assessment tool (EAT-10) and a flexible endoscopic evaluation of swallowing (FEES) is useful for predicting the incidence and risk factors of dysphagia after ADF. Methods: This prospective study comprised 60 consecutive patients who underwent ADF. An otolaryngologist and a speech-language-hearing therapist preoperatively and 1 week postoperatively evaluated dysphagia using EAT-10 and Hyodo-Komagane (H-K) scores during FEES. Patient demographics, comorbidities, and pre- and postoperative dysphagia were compared between patients with and without PRC. Results: Seven of 60 (11.6%) patients had preoperative dysphagia diagnosed using the H-K score. A significant positive correlation existed between the pre- and postoperative H-K scores. Of all 60 cases, eight (13.3%) had PRC. Among them, two required reintubation due to airway obstruction and six had aspiration pneumonia. The PRC(+) group was significantly older and more prone to diabetes and asthma. The preoperative H-K score of the PRC(+) group was significantly higher than that of the PRC(−) group. Postoperatively, but not preoperatively, EAT-10 was significantly higher in the PRC(+) group. Conclusions: Preoperative dysphagia may potentially exacerbate postoperative dysphagia after ADF. A preoperative evaluation of dysphagia using the H-K score during FEES is a useful method for predicting and reducing the risk of PRC. Level of Evidence: 3

Introduction: There is a significant relationship between pulmonary function and degree of spinal deformity, location of apical vertebrae, and coronal imbalance in patients with childhood spinal deformity. By contrast, the pathophysiology, epidemiology, and influence of deformity on respiratory dysfunction in patients with adult spinal deformity (ASD) remain largely unknown. We sought to clarify and compare the prevalence of pulmonary function impairment in patients with ASD with that in patients with lumbar spinal stenosis (LSS), to determine radiographically which spinal malalignment parameters are associated with a risk of respiratory dysfunction, and to determine the association of respiratory dysfunction with corrective surgery. Methods: We conducted a prospective study of consecutive patients with a diagnosis of ASD or LSS who underwent spinal surgery. We included data from 122 consecutive patients with ASD and 121 consecutive patients with LSS. Parameters were obtained from full-length lateral radiographs taken with the patients standing and in supine and prone positions. We compared respiratory dysfunction between a group of patients with ASD and LSS and determined correlations between respiratory dysfunction and spinopelvic parameters. Results: Preoperative % forced vital capacity (FVC) of patients with ASD was significantly lower than that of patients with LSS, and the frequency of restrictive ventilatory impairment was significantly higher in those with ASD (15.7%) than those with LSS (7.4%). Thoracolumbar kyphotic curvature (TK) while the patients were in supine position was significantly greater in the group with restrictive ventilatory impairment, and a significant negative correlation was found between %FVC and TK with the patients in supine position. We found no significant improvement of respiratory dysfunction 1 year after surgery. Conclusions: Spinal deformity is a potential risk factor for restrictive ventilatory impairment in the elderly. We propose that radiographs obtained when patients are in supine position are valuable for evaluating the flexibility of the TK. Rigid TK might be an etiology of restrictive ventilatory impairment in patients with ASD.

Abtsract Background Numerous comparative studies of surgical procedures have focused on clinical and radiographical outcomes, as well as the effect of bone fragility on the outcome of spinal surgery; however, insights concerning a risk of mortality or morbidity have been limited. Additionally, the effect of surgical therapy on survival after vertebral compression fractures remains controversial. Our aim was to evaluate the preoperative factors that affected the long-term survival of patients who underwent spinal surgery for an insufficient union following osteoporotic vertebral fractures (OVF) and to determine postoperative mortality. Methods We retrospectively reviewed the cases of 105 consecutive patients who underwent spinal surgery for OVF. Mortality was estimated using the Kaplan-Meier method and a log-rank test. The preoperative backgrounds of patients were analyzed to determine which risk factors led to death among the OVF cases. Kaplan-Meier curves were used to estimate survival based on preoperative albumin levels of ≤3.5 g/dL (hypoalbuminemia) versus > 3.5 mg/dL. Results The mean follow-up time was 4.1 ± 0.8 years. Two years after surgery, percentage of patients who had died was 15%. The VAS scores and modified Frankel classification were significantly improved one year after surgery. The ratio of male-to-female was significantly higher for patients with OVF who died than for those who were still alive. No significant difference in mortality was observed among surgical procedures for OVF. The univariate analysis showed that male gender, serum albumin

Introduction: We recently demonstrated that pelvic incidence (PI) decreases after long fusion using iliac screws (ISs) and plays a role in good sagittal balance postoperatively. By contrast, the IS loosening rate may cause reversion, increasing the PI and causing loss of sagittal balance. The aim of this study was to determine the effect of the number of ISs inserted into the iliac bone for long fusion to correct adult spinal deformities (ASDs) on the frequency of IS loosening, postoperative PI, and surgical outcomes. Methods: We included data from 70 consecutive patients. Cases in which two ISs were inserted bilaterally comprised the dual IS group (Group D), whereas cases in which one IS was inserted bilaterally comprised the single IS group (Group S). Results: IS loosening was observed in four patients in Group D (9%) and 14 patients in Group S (61%). Both early and one-year postoperative PI were significantly smaller in Group D (P < 0.001). The sagittal vertical axis (SVA) one-year postoperatively was significantly smaller in Group D (P = 0.003). Conclusions: The loosening rate of dual ISs was as low as about one-seventh that of single ISs. Using dual ISs, postoperative PI can be kept small, possibly resulting in a smaller SVA.

Introduction: The lateral lumbar interbody fusion (LLIF) surgical approach is minimally invasive and safely accesses the target region. Therefore, it is widely used in cases of lumbar spinal stenosis and spinal deformity. Intraoperative neuromonitoring is necessary to avoid nerve injury, whereas postoperative anterior thigh symptoms are not necessarily prevented. Technical Note: In our institute, 85 LLIF operations have been performed. The first 30 cases were excluded from the present study to avoid surgical learning curve effects; conventional monitoring was used in 30 cases, whereas a new method with a probe to monitor intramuscular potential was used in 25 other cases. Anterior thigh symptoms and motor deficits were assessed postoperatively. The location of the electromyographic threshold decrease was at the posterior part of the disc at L2-3, but at the anterior part at L4-5. Compared with conventional monitoring, the new intramuscular monitoring significantly decreased the prevalence of motor deficits of the iliopsoas at 1 day and 30 days; anterior thigh pain at 1 day, 30, and 90 days; and anterior thigh numbness at 30 and 90 days postoperatively. Conclusions: Compared with conventional monitoring, the new intramuscular monitoring with a less invasive probe may reduce anterior thigh symptoms.

Introduction: (1) To evaluate the influence of pedicle screw loosening on clinical outcomes; (2) to clarify the association between the pull-out length and screw loosening 1 year after surgery; and (3) to determine radiographically which screw parameters predominantly influence the pull-out resistance of screws. Methods: We analyzed 32 consecutive patients who underwent minimally invasive lumbar or thoracic spinal stabilization by intraoperative three-dimensional computed tomography (CT)-guided navigation without anterior reconstruction and were followed up for 1 year. The screw pull-out length was measured on axial CT images obtained both immediately after screw insertion and postoperatively. Loosening of screws and clinical outcomes were evaluated radiographically, clinically, and by CT 1 year after surgery. Results: There were no significant differences in the mean age, sex, bone mineral density, mean stabilized length, and smoking habits of patients with (+) or without (−) loosening. The Oswestry Disability Index and the lumbar visual analog scale 1 year after surgery were significantly higher in patients with loosening (+) than in those without (−). The overall pedicle screw pull-out rate was 16.2% (47/290) of screws and the overall screw loosening rate was 15.2% (44/290) of screws. Screws with loosening (+) had significantly lower (axial) trajectory angles and higher screw pull-out lengths than those without (−). Approximately 82% of loosened screws had been pulled out during rod connection. Conclusions: A lower axial trajectory and an increased screw pull-out length after rod reduction are crucial risk factors for screw loosening.

Abstract Spontaneous degeneration of an intervertebral disc is caused by inflammation that accompanies exposure of the avascular nucleus pulposus to circulation, triggering an autoimmune inflammatory reaction. Both intrinsic and extrinsic mechanisms of IVD regulation by various cytokines are involved in disc degeneration and spontaneous hernia resorption through inflammatory responses. The major goal of this narrative review was to assemble our past findings about the potential role of cytokines in disc diseases and to clarify directions for future research. A member of the tumor necrosis factor‐α (TNF‐α) superfamily, TNF‐like weak inducer of apoptosis (TWEAK) is constitutively expressed in the intervertebral disc, and induces a chronic, but relatively weak inflammatory response, thereby suppressing the formation of cartilage matrix and inducing production of matrix metalloproteinases (MMPs). Previously we indicated that TWEAK is involved in intervertebral disc degeneration by inhibiting the production of cartilage matrix in the intervertebral disc, and inducing the further expression of MMP‐3. Thymic stromal lymphopoietin (TSLP) is expressed primarily by epithelial cells, and induces inflammation at the time of tolerance failure in allergic disease. We found TSLP induced migration of immunocompetent cells to the disc in intervertebral disc disease by promoting the production of monocyte chemoattractant protein‐1 (MCP‐1) and macrophage inflammatory protein‐1 alpha (MIP‐1α) by the intervertebral disc and these cells may be involved in the resorption of herniated disc tissue. Considering the pivotal role of TWEAK and TSLP we review our current understanding of these factors and their involvement in disc degeneration.

Abstract Background Surgery for adult spinal deformity requires optimal patient-specific spino-pelvic-lower extremity alignment. Distal fixation in thoracolumbar spinal deformity surgery is crucial when arthrodesis to the sacrum is indicated. Although we had performed sacro-pelvic fixation with bilateral S1 and bilateral single iliac screws previously, iliac screw loosening and/or S1 screw loosening occurred frequently. So, the authors attempted to fuse spino-pelvic lesions with the dual iliac screws and S1 pedicle screws. Methods Twenty-seven consecutive adult spinal deformity patients underwent thoracolumbar-pelvic correction surgery with bilateral double iliac screws between May 2014 and September 2015. Sagittal vertical axis, lumbar lordosis, pelvic tilt, sacral slope, T1 pelvic angle, and global tilt were assessed radiographically and by computed tomography both preoperatively and 24 months postoperatively. Iliac screw loosening, S1 pedicle screw loosening, and screw penetration of the ilium were evaluated 2 years postoperatively. Results Only two patients (7.4%) at 1 year and three patients (11.1%) at 2 years presented with iliac screw loosening postoperatively. Loosening of the S1 screw occurred in three cases (11.1%) 2 years postoperatively. Displacement of the iliac screw occurred in eight cases (25%). Internal and external perforation of the ilium by the iliac screw occurred in six (22.2%) and three (11.1%) cases respectively. One reoperation was performed due to back-out of the iliac screw and rod breakage. Conclusion Bilateral dual iliac screws and an S1 pedicle screw system achieve longer stability for spinal and pelvic fusion in adult spinal deformity patients, with few severe complications.

Abstract Background Identification of poor prognostic factors for OVF is important but has not yet been clearly established. Despite paraspinal muscles could play an important role in the etiology of OVF, what influence time-dependent changes in paraspinal muscles have after OVF, and the impact on conservative treatments for patients who have an OVF remain largely unknown. The purposes of this study were to (1) evaluate time-dependent changes of the paraspinal musculature using MRI after injury in patients with osteoporotic vertebral fractures (OVFs), and (2) compare paraspinal muscles between conservatively treated patients with OVF who have successful union and those failed to conservative treatment. Methods A total of 115 consecutive patients who had sustained a recent OVF injury in the thoracolumbar region were assessed for eligibility using medical records and all required data were available from 90 patients who had been followed up for at least 6 months. Patients who needed to undergo surgery and patients who were diagnosed as having insufficient union after 6 months of follow-up were assigned to a group with insufficient union. Lumbar trunk parameters, relative cross-sectional area (rCSA) and proportion of fat infiltration (FI%) were calculated from MRI. To evaluate the time-dependent changes in the paraspinal muscle in patients after OVF injury, correlations between the timing of MRI and rCSA, FI% were determined. To clarify the impact of paraspinal muscles on the outcome of conservative treatments of patients with OVF, we compared rCSA between the groups. Results Sixty-five patients were assigned to a group with insufficient union and 25 patients were assigned to a group with successful union. FI% of the multifidus and erector spinae in the group with insufficient union were significantly greater than in the group with union. The timing of MRI in relation to initial injury was significantly correlated with FI% of the multifidus and erector spinae. rCSA of the erector spinae was significantly larger in the group with successful union than in the group with insufficient union. Conclusions These findings indicated a time-dependent increase of fatty degeneration of the multifidus and erector muscles, but no change in the rCSA and larger rCSAs of spinal erectors may play a role in successful union in patients with OVF.

Abstract Background In patients with ossification of the posterior longitudinal ligament (OPLL) in the cervical spine, it is well known that the thoracic ossified lesions often coexist with the cervical lesions and can cause severe myelopathy. However, the prevalence of OPLL at each level of the thoracic and lumbar spinal segments is unknown. The aims of this study were to investigate how often OPLL occurs at each level in the thoracolumbar spine in patients with a radiological diagnosis of cervical OPLL and to identify the spinal levels most likely to develop ossification. Methods Data were collected from 20 institutions in Japan. Three hundred and twenty-two patients with a diagnosis of cervical OPLL were included. The OPLL index (OP index), defined as the sum of the vertebral body and intervertebral disc levels where OPLL is present, was used to determine disease severity. An OP index ≥20 was defined as severe OPLL. The prevalence of OPLL at each level of the thoracic and lumbar spinal segments was calculated. Results Women were more likely to have ossified lesions in the thoracolumbar spine than men. Severe OPLL was significantly more common in women than in men (20% vs. 4.5%). For thoracic vertebral OPLL, the most frequently affected was the T1 segment in both men and women, followed by the T1/2 and T3/4 intervertebral levels in men and women, respectively. Ossified lesions were frequently seen at the intervertebral and vertebral levels around the cervicothoracic and thoracolumbar junctions in men with severe OPLL, whereas OPLL was more diffusely distributed in the thoracic spine in women with severe OPLL. Conclusion Thoracolumbar OPLL occurred most often at T1 in men and at T3/4 in women. In severe OPLL cases, although ossified lesions were frequently seen at the intervertebral and vertebral levels around the cervicothoracic and thoracolumbar junctions in men, OPLL could be observed more diffusely in the thoracic spine in women.

Introduction: To comprehensively investigate the anatomy of the neuromuscular, visceral, vascular, and urinary tissues and their general influence on lateral lumbar interbody fusion (LLIF) surgery in the presence or absence of spinal deformity. Methods: We retrospectively reviewed 100 consecutive surgery cases for lumbar degenerative disease of patients aged on average 70.5 years and of which 67 were women. A sagittal vertical axis deviation of more than 50 mm was defined as adult spinal deformity (ASD: 50 patients). The degenerative disease of the other patients was defined as lumbar spinal stenosis (LSS: 50 patients). We analyzed the relative anatomical position of the psoas major muscle, lumbar plexus, femoral nerves, inferior vena cava, abdominal aorta and its bifurcation, ureter, testicular or ovarian artery, kidney and transverse abdominal muscle in patients with ASD or with LSS, using preoperative magnetic resonance imaging (MRI). Results: For patients with ASD, the L4-5 intervertebral disk was closer to the lumbar nerve plexus than it was in those with LSS (p < 0.0001), and a rising psoas sign at the L4-5 disk was significantly more frequent in patients with ASD than in those with LSS (p < 0.05). The aortic bifurcation frequently appeared at the level of L4-5 in patients with either degenerative disease, so the common iliac artery may pass near the disk. The inferior vena cava passed closer to the center of the L4-5 disk in patients with ASD than it did in those with LSS (p < 0.05). The transverse abdominal muscle at L2-3, L3-4, and L4-5 was closer to and less than 3 mm from the kidneys in many more patients with ASD than was the case for patients with LSS (p = 0.3, p < 0.05, p = 0.29, respectively). Conclusions: We recommend careful preoperative MRI to determine the location of organs to help to avoid intraoperative complications during LLIF surgery, especially for patients with ASD.

Abstract Background Gastroesophageal reflux disease (GERD) is a factor that has a significant negative impact on the quality of life (QoL). Vertebral fractures and/or spinal malalignment may influence the frequency of GERD. However, the epidemiology and pathology of GERD in patients with adult spinal deformity (ASD) are still largely unknown. To establish the optimal surgical strategy for GERD in patients treated surgically for ASD, we sought to clarify the GERD prevalence, determine radiographically which spinal malalignment parameters influence GERD risk, and evaluate GERD improvement postoperatively. Methods Seventy-one consecutive patients with ASD who were treated with thoracolumbar corrective surgery and followed up for at least 1 year were enrolled. GERD was diagnosed by a gastroenterologist based on proton pump inhibitor medication response and/or an FSSG score > 8 points. Full-length lateral radiographs in a standing posture and in a supine, fulcrum backward-bending (FBB) position were taken preoperatively and 1 year postoperatively, and radiographic parameters were obtained. Correlations between radiographic parameters and FSSG scores were determined by Pearson’s correlation coefficient. Multivariate logistic regression analyses were performed to evaluate the odds ratio (OR) with a 95% confidence interval (95% CI) for potential risk factors for GERD. Results Patients were classified into two groups based on GERD symptoms, with 37 (52%) in the GERD+ group. Thoracolumbar kyphosis (TLK) in the FBB position was significantly more common in the GERD+ versus the GERD− group. Multivariate logistic regression analysis showed that lumbar lordosis (LL) and TLK curve in the FBB position significantly influenced the presence of GERD. Other factors showed no association with GERD. Significant improvements in FSSG scores were noted 1 year postoperatively. However, 20 (28.2%) patients still had GERD symptoms. The postoperative TLK curve was highly significantly correlated with FSSG scores 1 year postsurgery. Conclusions Of the 71 patients treated surgically for ASD, 37 (52%) had a high frequency of GERD symptoms. An inflexible thoracolumbar curve with increased TLK in the FBB position was significantly associated with GERD symptoms. Despite significant improvements in FSSG scores postoperatively, insufficient correction of TLK might be a risk factor for persistent GERD symptoms.

Introduction: Through an extreme lateral retroperitoneal and transpsoas approach to intervertebral disc and fusion surgery, a large lordosis cage can be placed for solid and stable intervertebral fusion and to provide strong anterior support, disc height restoration, favorable alignment, and indirect nerve decompression. However, appropriate placement of the interbody cage remains insufficiently researched. We sought to determine both appropriate cage placement as well as other factors affecting nerve decompression in extreme lateral interbody fusion (XLIF) surgery. Methods: We included 53 consecutive patients suffering from lumbar degenerative diseases with an indication for XLIF. Radiographic analysis using a sagittal computed tomography (CT) and axial magnetic resonance imaging (MRI) views was conducted to determine intervertebral disc height and angle, degree of disc bulging and thickness of the flavum, the area of the dural tube, cage height, pre- and postoperative disc bulging, change of disc bulging after surgery, cage subsidence, and cage placement at the rostral and caudal endplates. Results: Intervertebral disc height and angle were significantly increased at all levels (L2/3, 3/4, 4/5) (p < 0.05). The area of the dural tube was significantly increased (p < 0.05), whereas the degree of disc bulging and thickness of the flavum were significantly decreased at all disc levels (p < 0.05). The enlarged area of the dural tube showed significant correlation with increased disc height (p = 0.019), preoperative flavum thickness (p = 0.008), change of flavum thickness (p < 0.0001), and cage placement at the rostral endplate (p = 0.014). Conclusions: A decrease in flavum buckling is more important than disc protrusion as a consideration for obtaining indirect decompression. Central placement may be advantageous for indirect decompression.

Abstract Background The benefits of extreme lateral interbody fusion (XLIF) as a minimally invasive lumbar spinal fusion treatment for lumbar degenerative spondylolisthesis have been unclear. We sought to evaluate the invasiveness and tolerability of XLIF with percutaneous pedicle screws (PPS) compared with traditional open posterior lumbar interbody fusion (PLIF). Methods Fifty-six consecutive patients underwent open PLIF and 46 consecutive patients underwent single-staged treatment with XLIF with posterior PPS fixation for degenerative lumbar spondylolisthesis, and were followed up for a minimum of 1 year. We analyzed postoperative serum makers for muscle damage and inflammation, postoperative surgical pain, and performance status. A Roland–Morris Disability Questionnaire (RDQ) and Oswestry Disability Index (ODI) were obtained at the time of hospital admission and 1 year after surgery. Results Intraoperative blood loss (51 ± 41 ml in the XLIF/PPS group and 206 ± 191 ml in the PLIF group), postoperative WBC counts and serum CRP levels in the XLIF/PPS group were significantly lower than in the PLIF group. Postoperative serum CK levels were significantly lower in the XLIF/PPS group on postoperative days 4 and 7. Postoperative recovery of performance was significantly greater in the XLIF/PPS group than in the PLIF group from postoperative days 2 to 7. ODI and visual analog scale (VAS) score (lumbar) 1 year after surgery were significantly lower in the XLIF/PPS group compared with the PLIF group. Conclusions The XLIF/PPS procedure is advantageous to minimize blood loss and muscle damage, with consequent earlier recovery of daily activities and reduced incidence of low back pain after surgery than with the open PLIF procedure.

Case. Generally, well-differentiated liposarcoma (WDL) has recurrence potential but lacks metastatic potential. We present a rare case of spinal metastasis of WDL component in retroperitoneal dedifferentiated liposarcoma (DDL) treated by tumor curettage and L1 laminectomy followed by percutaneous pedicle screw fixation. Histological examination showed metastasis of the WDL component of DDL. The patient was ambulatory until death. Conclusion. To our knowledge, no case of spinal metastasis of WDL component in retroperitoneal DDL has been reported. We should carefully consider characteristics of DDLs during treatment. Minimally invasive surgery may be a powerful tool in patients with spinal metastasis.

This case report describes a unique case involving traumatic spondylolisthesis of the axis that resulted in nonunion, angulation, and displacement after conservative treatment with a cervical collar, but which was successfully achieved union with halo immobilization and low-intensity pulsed ultrasound (LIPUS). Halo immobilization of a traumatic spondylolisthesis in a 20-year-old patient, that previously failed to improve after wearing a cervical collar for 3 months, was immediately followed by treatment with a LIPUS device (SAFHS 4000J; Teijin Pharma, Tokyo, Japan) 20 minutes once daily to the right and left fracture sites which were located using fluoroscopic guidance. Radiographs and computed tomography showed conclusive evidence of bone union after 10 weeks of treatment with halo immobilization. No adverse events were observed. To the best of our knowledge, this is the first report describing that the combination of halo immobilization and LIPUS therapy might be a safe, effective, and feasible method by which to treat cervical spine fractures.

Radiographic imaging plays a crucial role in the diagnosis of osteosarcoma. Currently, computed-tomography (CT) is used to measure tumor-induced osteolysis as a marker for tumor growth by monitoring the bone fractional volume. As most tumors primarily induce osteolysis, lower bone fractional volume has been found to correlate with tumor aggressiveness. However, osteosarcoma is an exception as it induces osteolysis and produces mineralized osteoid simultaneously. Given that competent bone is highly anisotropic (systematic variance in its architectural order renders its physical properties dependent on direction of load) and that tumor induced osteolysis and osteogenesis are structurally disorganized relative to competent bone, we hypothesized that μCT-derived measures of anisotropy could be used to qualitatively and quantitatively detect osteosarcoma provoked deviations in bone, both osteolysis and osteogenesis, in vivo. We tested this hypothesis in a murine model of osteosarcoma cells orthotopically injected into the tibia. We demonstrate that, in addition to bone fractional volume, μCT-derived measure of anisotropy is a complete and accurate method to monitor osteosarcoma-induced osteolysis. Additionally, we found that unlike bone fractional volume, anisotropy could also detect tumor-induced osteogenesis. These findings suggest that monitoring tumor-induced changes in the structural property isotropy of the invaded bone may represent a novel means of diagnosing primary and metastatic bone tumors.

Objectives: Histopathological synovitis scoring is useful for assessing activity in patients with rheumatoid arthritis (RA) at sampling, but it is unclear whether it can be a predictor of future drug treatment. The purpose of this study was to examine whether histopathological synovitis score is a predictor of postoperative requirement for additional or alternative drug treatment after total knee arthroplasty (TKA). Methods: Thirty patients with RA in whom synovial samples were obtained during TKA were included. Patients were divided into the drug treatment enhanced group (EG), which included patients who needed additional or alternative drug treatment within 1 year after TKA, and the drug treatment maintenance group (MG). The Rooney synovitis score (RSS) was compared between groups. Logistic regression analysis was performed to clarify prognostic factors for postoperative drug treatment change. Results: The total RSS was significantly higher in the EG than in the MG (29.3 vs 15.1; P < .001). Multivariate analysis showed that total RSS and swollen joint counts were independent variable associated with postoperative requirement for additional or alternative drug treatment (P < .05). Conclusions: Histopathological synovitis scoring may predict requirement for additional or alternative drug treatment in patients with RA after TKA. [ABSTRACT FROM AUTHOR]