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This article was updated on October 19, 2022, because of previous errors, which were discovered after the preliminary version of the article was posted online. On page 1787, in the legend for Figure 2, the sentence that had read "The vertebral collapse rate (in %) was defined as 1 - (A/P) × 100, and vertebral instability (in %) was defined as the difference in vertebral collapse rate between the loaded and non-loaded images." now reads "The vertebral collapse rate (in %) was defined as (1 - [A/P]) × 100, and vertebral instability (in %) was defined as the difference in vertebral collapse rate between the loaded and non-loaded images." On page 1788, in the section entitled "Data Collection," the sentence that had read "The vertebral collapse rate (in %) was defined as 1 - (anterior vertebral wall height/posterior vertebral wall height) × 100, and vertebral instability (in %) was defined as the difference in vertebral collapse rate between the loaded and non-loaded images 9 ." now reads "The vertebral collapse rate (in %) was defined as (1 - [anterior vertebral wall height/posterior vertebral wall height]) × 100, and vertebral instability (in %) was defined as the difference in vertebral collapse rate between the loaded and non-loaded images 9 ." Finally, on page 1791, in Table IV, the footnote for the "Primary outcome" row that had read "N = 113 in the rest group and 99 in the no-rest group." now reads "N = 116 in the rest group and 108 in the no-rest group."Although imaging findings that predict resistance to conservative treatment in patients with osteoporotic vertebral fracture (OVF) have recently been reported, no conservative treatment method has been standardized. In this study, the effects of initial bed rest on the outcomes of patients with OVF and in patients with and without poor prognostic findings on magnetic resonance imaging (MRI) were compared. This prospective cohort study at 2 facilities involved consecutive patients aged ≥65 years with OVF who began treatment within 2 weeks after their injury and were observed for 6 months. Patients at one hospital rested for 2 weeks (116 patients; mean age, 80.4 years), whereas those at the other hospital were not instructed to rest (108 patients; mean age, 81.5 years). Patients were further divided according to the presence or absence of poor prognostic MRI findings. The primary end point was the rate of transition to surgery; secondary end points included bone union rate, vertebral collapse progression, local kyphosis progression, and changes in activities of daily living (ADL). Forty-five patients in the rest group (including 3 who required surgery) and 37 patients in the no-rest group (including 9 who required surgery) had poor prognostic MRI findings. Although the difference in the rate of transition to surgery between the rest and no-rest groups did not reach significance among all patients (p = 0.06), the transition rate in the rest group was significantly lower (p = 0.02) in the patients with poor prognostic MRI findings. Both the bone union rate and changes in ADL were not significantly different between the rest and no-rest groups. The mean vertebral collapse progression was 6.4% in the rest group and 20.9% in the no-rest group (p0.001), and the mean local kyphosis progression was 2.4° in the rest group and 8.8° in the no-rest group (p0.001). Although bed rest is not recommended for all patients, hospitalized bed rest for 2 weeks reduced the number of patients with OVF who require surgery among patients with poor prognostic MRI findings. Bed rest also reduced progression of vertebral collapse and kyphosis, regardless of the MRI findings. Therapeutic Level II . See Instructions for Authors for a complete description of levels of evidence.

Recent studies have reported that confined high-intensity and diffuse low-intensity on sagittal T2-weighted magnetic resonance imaging (MRI) are distinctive features that are highly predictive of delayed union or nonunion on osteoporotic vertebral fracture (OVF). The objective of this study was to identify the characteristics of imaging findings predicting the risk for requiring surgical treatment in fresh OVF with poor prognostic features on MRI.We conducted a retrospective study of 74 patients (17 men and 57 women with a mean age of 81.1 years) of OVF with the poor prognostic MRI findings. We compared the imaging findings between the surgery group (16 patients) and the conservative group (58 patients): vertebral instability defined as the difference between the vertebral collapse ratio in dynamic X-rays, and the grade of posterior wall injury (Grade I, no spinal canal encroachment; Grade II,2 mm; Grade III, ≥2 mm) as well as the presence or absence of pedicle fracture (Grade I, none; Grade II, unilateral; Grade III, bilateral) on computed tomography.The mean vertebral instability was 24.0% ± 10.1% in the surgery group and 13.0% ± 7.8% in the conservative group, which was significantly different. Posterior wall injury in the surgery and conservative groups was Grade I in 0 and 29 cases, Grade II in 5 and 21 cases, and Grade III in 11 and 8 cases, respectively, constituting a significant difference. Pedicle fracture in the surgery and conservative groups was Grade I in 5 and 55 cases, Grade II in 6 and 2 cases, and Grade III in 5 and 1 case, respectively, also constituting a significant difference.The most high-risk OVF patients with poor prognostic MRI findings who required surgical treatment were those who exhibited greater vertebral instability as well as either more severe posterior wall injury or pedicle fracture.Retrospective clinical study.

The usefulness of minimally invasive posterior fixation without debridement and autogenous bone grafting remains unknown. This multicenter case series aimed to determine the clinical outcomes and limitations of this method for thoracolumbar pyogenic spondylitis. Patients with thoracolumbar pyogenic spondylitis treated with minimally invasive posterior fixation alone were retrospectively evaluated at nine affiliated hospitals since April 2016. The study included 31 patients (23 men and 8 women; mean age, 73.3 years). The clinical course of the patients and requirement of additional anterior surgery constituted the study outcomes. The postoperative numerical rating scale score for lower back pain was significantly smaller than the preoperative score (5.8 vs. 3.6, p = 0.0055). The preoperative local kyphosis angle was 6.7°, which was corrected to 0.1° after surgery and 3.7° at the final follow-up visit. Owing to failed infection control, three patients (9.6%) required additional anterior debridement and autogenous bone grafting. Thus, in this multicenter case series, a large proportion of patients with thoracolumbar pyogenic spondylitis could be treated with minimally invasive posterior fixation alone, thereby indicating it as a treatment option for pyogenic spondylitis.

Study design This was a prospective multicenter study. Objective The aim of this study was to investigate the perioperative complications of posterior surgeries for the treatment of cervical ossification of the posterior longitudinal ligament (OPLL). Summary of background data Surgical treatment for cervical OPLL has a high risk of various complications. Laminoplasty (LAMP) and posterior decompression and instrumented fusion (PDF) are effective for multilevel cervical OPLL; however, few studies have focused on the surgical complications of these 2 procedures. Materials and methods We prospectively included 380 patients undergoing posterior surgeries for cervical OPLL (LAMP: 270 patients, PDF: 110 patients), and investigated the systemic and local complications, including neurological complications. We further evaluated risk factors related to the neurological complications. Results Motor palsy was found in 40 patients (10.5%), and motor palsy in the upper extremity was most frequent (8.9%), especially in patients who received PDF (14.5%). Motor palsies involving the lower extremities was found in 6 patients (1.6%). Regarding local complications, dural tears (3.9%) and surgical site infections (2.6%) were common. In the univariate analysis, body mass index, preoperative cervical alignment, fusion surgery, and the number of operated segments were the factors related to motor palsy. Multivariate analysis revealed that fusion surgery and a small preoperative C2-C7 angle were the independent factors related to motor palsy. Motor palsy involving the lower extremities tended to be found at early time points after the surgery, and all the patients fully recovered. Motor palsy in the upper extremities occurred in a delayed manner, and 68.8% of patients with PDF showed good recovery, whereas 81.3% of patients with LAMP showed good recovery. Conclusions In posterior surgeries for cervical OPLL, segmental motor palsy in the upper extremity was most frequently observed, especially in patients who received PDF. Fusion and a small preoperative C2-C7 angle were the independent risk factors for motor palsy. Level of evidence Level III.

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.

Study design A retrospective analysis of prospectively collected data. Objective This study aimed to create a prognostic model for surgical outcomes in patients with cervical ossification of the posterior longitudinal ligament (OPLL) using machine learning (ML). Summary of background data Determining surgical outcomes helps surgeons provide prognostic information to patients and manage their expectations. ML is a mathematical model that finds patterns from a large sample of data and makes predictions outperforming traditional statistical methods. Methods Out of 478 patients, 397 and 370 patients had complete follow-up information at 1 and 2 year respectively and were included in the analysis. A minimal clinically important difference (MCID) was defined as an acquired Japanese Orthopaedic Association (JOA) score of 2.5 points or more, after which a ML model that predicts whether MCID can be achieved 1 and 2 years after surgery was created. Patient background, clinical symptoms, and imaging findings were used as variables for analysis. The ML model was created using LightGBM, XGBoost, random forest, and logistic regression, after which the accuracy and area under the receiver operating characteristic curve (AUC) were calculated. Results The mean JOA score was 10.3 preoperatively, 13.4 at 1 year after surgery, and 13.5 at 2 years after surgery. XGBoost showed the highest AUC (0.72) and high accuracy (67.8) for predicting MCID at 1 year, while random forest had the highest AUC (0.75) and accuracy (69.6) for predicting MCID at 2 years. Among the included features, total preoperative JOA score, duration of symptoms, body weight, sensory function of the lower extremity sub-score of the JOA, and age were identified as having the most significance in most of ML models. Conclusion Constructing a prognostic ML model for surgical outcomes in patients with OPLL is feasible, suggesting the potential application of ML for predictive models of spinal surgery.Level of Evidence: 4.

STUDY DESIGN A prospective multicenter study. OBJECTIVE To evaluate and compare the surgical outcomes after open-door (OD) and double-door (DD) laminoplasties in subjects with cervical ossification of the posterior longitudinal ligament (OPLL). SUMMARY OF BACKGROUND DATA Although previous studies compared clinical results after OD and DD laminoplasties, they were performed at a single institution with a relatively small sample size targeting mixed pathologies, including cervical spondylotic myelopathy. METHODS This study was performed by the Japanese Multicenter Research Organization for Ossification of the Spinal Ligament. A total of 478 patients with myelopathy caused by cervical OPLL from 28 institutions were prospectively registered from 2014 to 2017 and followed up for 2 years. Of these, 41 and 164 patients received OD and DD laminoplasties, respectively. Demographic information, medical history, and imaging findings were collected. Clinical outcomes were assessed using the cervical Japanese Orthopaedic Association, Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire, and visual analog scale scores. RESULTS Age, sex, symptom duration, and comorbidities were not significantly different between the groups. Segmental ossification was the most frequent in both the groups. No significant differences in K-line type, canal occupying ratio, C2 to C7 angles, and range of motion were found. Both the procedures reduced the cervical range of motion postoperatively. A comparable frequency of perioperative complications was observed between the groups. The cervical Japanese Orthopaedic Association scores showed a similar improvement at 2 years postopera- tively. The reduction in visual analog scale score for neck pain was favorable in the OD group (P = 0.02), while other pain assessments did not show any significant differences between the groups. The functional outcomes assessed using the Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire presented equivalent effective rates. CONCLUSION The results demonstrated almost comparable surgical outcomes between OD and DD laminoplasties. Lamino- plasty is a valuable technique as a therapeutic option for cervical OPLL.Level of Evidence: 2.

Study design Prospective, nationwide case series. Objective To identify preoperative factors associated with myelopathy and neurological impairment in patients with cervical ossification of the posterior longitudinal ligament (OPLL). Summary of background data Various studies have reported clinical outcomes following the surgical treatment of OPLL. However, there has been no large-scale study of preoperative clinical features in patients with cervical OPLL. Materials and methods Data were prospectively collected from 28 institutions nationwide in Japan. In total, 512 patients with neurological impairment caused by cervical OPLL requiring surgery were enrolled. Basic demographic and clinical data, including age, sex, diabetes status, body mass index, smoking history, and disease duration were collected. C2-7 lordotic angle, canal narrowing ratio, range of motion in flexion-extension at C2-7, and type of OPLL were evaluated on lateral radiographs to identify factors influencing the clinical features of patients with OPLL in whom surgery was planned. Results Complete documentation was available for 490 patients (362 male, 128 female). In total, 34 patients had the localized type, 181 had the segmental type, 64 had the continuous type, and 211 had the mixed type. Although there were no significant differences in age, body mass index, disease duration, Japanese Orthopedic Association (JOA) score, and lordotic angle at C2-7 according to the type of OPLL, significant differences were observed in a range of motion at C2-7 and the canal narrowing ratio among the 4 types. Multiple regression analysis revealed that the JOA score was significantly associated with age and signal intensity change on magnetic resonance imaging. Conclusions This is the first large-scale, prospective, multicenter case series study to investigate factors influencing preoperative neurological status in patients with OPLL. Age and signal intensity change on magnetic resonance images were significantly associated with JOA score in patients requiring surgery. Level of evidence Level II.

Although diffuse idiopathic skeletal hyperostosis (DISH) is generally asymptomatic, in rare cases it involves multiple segments and can present with intervertebral pseudoarthrosis which requires treatment. We report a case of a 47-year-old female patient with intervertebral pseudoarthrosis and severe dynamic instability in the L4–5 intervertebral disc due to DISH and provide a brief review of literature. The patient developed severe lower back pain and intermittent claudication due to the instability in the only mobile part between multiple fused vertebrae from C7 to L4 and fusion segment from L5 to the ilium. We performed long-range posterior spinal and two-stage 360° fusion with L4–5 lateral interbody fusion. After the surgery the pain and intermittent claudication were improved and bony fusion was successful. Reports of intervertebral pseudoarthrosis in DISH with no history of trauma are extremely rare. We have only been able to find 5 cases. Compared to the previous reports, the present case describes a youngest patient, first case of female, and had the longest fusion due to DISH. Therefore, the patient required long-range fusion from T10 to the iliac bone in order to achieve adequate stabilization. Moreover, the present case is the first example of choosing a lateral interbody fusion, which provides even more robust consolidation.

Postoperative neck pain has been reported as an unsolved postoperative complication of surgery for cervical ossification of the posterior longitudinal ligament (OPLL). The aim of the present study was to elucidate factors having a significant association with postoperative deterioration of neck pain in cervical OPLL patients. We studied a cohort of patients in a prospective registry of 478 patients who had undergone cervical spine surgery for cervical OPLL. We excluded those without evaluation of preoperative neck pain. Therefore, 438 patients were included in the present study. Neck pain was evaluated with the visual analogue scale (VAS, 0–100 mm). Postoperative neck pain deterioration was defined as a ≥20 mm increase of VAS neck pain. Patient factors, neurological status, imaging factors and surgical factors were assessed. Univariate analyses followed by multivariate analysis using stepwise logistic regression was performed. Six months after surgery, 50 (11.6%) patients showed postoperative neck pain deterioration and 76 (17.4%) patients showed postoperative neck pain deterioration 2 years after surgery. Six months after surgery, the rate of neck pain deterioration was significantly higher in patients who had undergone posterior surgery. Two years after surgery, the number of levels fused was significantly correlated with neck pain deterioration.

OBJECTIVE It is unclear whether anterior cervical decompression and fusion (ADF) or laminoplasty (LMP) results in better outcomes for patients with K-line–positive (+) cervical ossification of the posterior longitudinal ligament (OPLL). The purpose of the study is to compare surgical outcomes and complications of ADF versus LMP in patients with K-line (+) OPLL. METHODS The study included 478 patients enrolled in the Japanese Multicenter Research Organization for Ossification of the Spinal Ligament and who underwent surgical treatment for cervical OPLL. The patients who underwent anterior-posterior combined surgery or posterior decompression with instrumented fusion were excluded. The patients with a follow-up period of fewer than 2 years were also excluded, leaving 198 patients with K-line (+) OPLL. Propensity score matching was performed on 198 patients with K-line (+) OPLL who underwent ADF (44 patients) or LMP (154 patients), resulting in 39 pairs of patients based on the following predictors for surgical outcomes: age, preoperative Japanese Orthopaedic Association (JOA) score, C2–7 angle, and the occupying ratio of OPLL. Clinical outcomes were assessed 1 and 2 years after surgery using the recovery rate of the JOA score. Complications and reoperation rates were also investigated. RESULTS The mean recovery rate of the JOA score 1 year after surgery was 55.3% for patients who underwent ADF and 42.3% (p = 0.06) for patients who underwent LMP. Two years after surgery, the recovery rate was 53.4% for those who underwent ADF and 38.7% for LMP (p = 0.07). Although both surgical procedures yielded good results, the mean recovery rate of JOA scores tended to be higher in the ADF group. The incidence of surgical complications, however, was higher following ADF (33%) than LMP (15%; p = 0.06). The reoperation rate was also higher in the ADF group (15%) than in the LMP group (0%; p = 0.01). CONCLUSIONS Clinical outcomes were good for both ADF and LMP, indicating that ADF and LMP are appropriate procedures for patients with K-line (+) OPLL. Clinical outcomes of ADF 1 and 2 years after surgery tended to be better than LMP, but the analysis did not detect any significant difference in clinical outcomes between the groups. Conversely, patients who underwent ADF had a higher incidence of surgery-related complications. When considering indications for ADF or LMP, benefits and risks of the surgical procedures should be carefully weighed.

Objectives To describe the novel technique of continuous local antibiotic perfusion (CLAP) for a surgical site infection (SSI) after instrumented spinal surgery. Methods CLAP was applied to 4 continuous patients at our institution who developed SSI after instrumented spinal surgery. Results All 4 patients were successfully treated and the infection was controlled. The implant was retained in all patients. The duration of CLAP ranged from 2 to 3 weeks. The blood level of the antibiotic used (gentamicin) at 1 week after the initiation of CLAP did not increase in any patient. No other adverse events occurred in any patient. Dramatic improvements in laboratory parameters, including the white blood cell (WBC) counts and C-reactive protein (CRP) levels were seen in every patient at 1 week after the initiation of CLAP. Conclusions CLAP controlled the infection without severe adverse events in all 4 patients, and the implants were retained. Despite its cost and the discomfort of patients, CLAP may become an option for the treatment of SSIs after instrumented spinal surgery. A large number of case series are needed to verify the efficacy of CLAP for patients with SSIs after instrumented spinal surgery.

Pyogenic spondylitis is a challenging condition that requires early and accurate diagnosis for appropriate treatment. Most cases can be treated non-surgically or with minimally invasive surgical procedures; however, a combination of anterior debridement/bone grafting and posterior fixation is necessary for severe cases. We encountered a case of lumbar pyogenic spondylitis treated with anterior debridement and autogenous bone grafting after percutaneous endoscopic discectomy drainage (PEDD) with percutaneous pedicle screw (PPS) fixation. The continuous pus oozing from the PEDD drainage tube wound was characteristic in this case, and the pus was considered to be caused by secondary infection/microbial substitution. The discharge immediately stopped and healed after anterior debridement and autogenous bone grafting. Escherichia coli was first detected as the causative bacterium, and Corynebacterium amycolatum and Corynebacterium striatum were detected as the cause of secondary infection/microbial substitution. The possibility of secondary infection/microbial substitution should be considered when the clinical course worsens.

We used a newly developed, high-porosity unidirectional porous hydroxyapatite spacer (Regenos spacer, not approved by the FDA). To assess the short-term bone bonding capacity of Regenos spacer used in a double-door laminoplasty, including displacement, deformation, and absorption after implantation. Fifty patients underwent a double-door laminoplasty using Regenos spacers, with computed tomography (CT) images obtained at 2-4 weeks and 6-12 months, post-surgery, in 30 patients. Bone bonding rate, amount of displacement, and the incidence of deformation and absorption were evaluated from the early and late postoperative CT images. Bone bonding rate for Regenos spacers, using our modified classification, was 48.9% at 6 months, post- surgery, and 67.0% at 12 months. The change in anterior-posterior diameter of the spinal canal (ΔH) was significantly greater for Regenos spacers than for autologous bone spacers (p 0.05). There was no difference in the change in angle between the vertebral arch and the posterior wall of the vertebral body (ΔR) between the Regenos and autologous bone spacers. Deformation was identified in 21.3% (10/47). Though, no evidence of breakage along their long axis was identified among these 10 cases on axial CT images with passable clinical results. Regenos spacers lowered the risk of early dislocation after implantation and facilitated bone bonding due to infiltration of surrounding tissue. However, the deformation and absorption was observed at high rates because of their insufficient mechanical strength, we need to require a longer term follow-up to more clearly evaluate their adverse impact in clinically.

This prospective multicenter study formed by the Japanese Ministry of Health, Labour and Welfare at 27 institutions aimed to compare postoperative outcomes between laminoplasty (LM) and posterior fusion (PF) for cervical ossification of the posterior longitudinal ligament (OPLL). Controversy exists regarding the role of instrumented fusion in the context of posterior surgical decompression for OPLL. Among the 479 patients enrolled, 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, patient backgrounds, radiographical measurements (K-line or cervical alignment on X-ray, OPLL occupation ratio on computed tomography, and increased signal intensity change on magnetic resonance imaging), or clinical status (JOA score and JOACMEQ) after adjustments showed no significant differences. The overall risk of perioperative complications was lower in LM (odds ratio [OR] 0.40, p = 0.006), and C5 palsy was significantly lower in LM (OR 0.11, p = 0.0002) than in PF. The range of motion (20.91° ± 1.05° and 9.38° ± 1.24°, p

The chemical states of heavy metals and radioactive Cs were estimated in fly ash sampled at Fukushima prefecture, Japan. Estimating the speciation of incinerator fly ash is important to ensure an appropriate and efficient management of fly ash generated from disaster-related waste. In this study, fly ash collected at a waste incineration facility in Fukushima prefecture was treated using a sequential extraction test. The test results indicated that the solubility behavior of radioactive Cs was similar to that of NaCl and KCl, and approximately 60% of radioactive Cs was included as water-soluble chloride compounds in the fly ash sample. Most heavy metals eluted in three fractions, in the extraction steps for carbonate-bound, free oxide, and bound to organic matter species. The chemical states of elements in the three non-water-soluble fractions and residue showed minimal elution into the environment. Therefore, most heavy metals in the fly ash exhibited minimal elution into the environment.

STUDY DESIGN Retrospective cohort study. OBJECTIVE To clarify the poor patient satisfaction after lumbar spinal surgery in elderly patients. SUMMARY OF BACKGROUND DATA As the global population continues to age, it is important to consider the surgical outcome and patient satisfaction in the elderly. No studies have assessed patient satisfaction in elderly patients undergoing surgical treatment and risk factors for poor satisfaction in elderly patients after lumbar spinal surgery. MATERIALS AND METHODS A retrospective multicenter survey was performed in 169 patients aged above 80 years who underwent lumbar spinal surgery. Patients were followed up for at least 1 year after surgery. We assessed patient satisfaction from the results of surgery by using a newly developed patient questionnaire. Patients were assessed by demographic data, surgical procedures, complications, reoperation rate, pain improvement, and risk factors for poor patient satisfaction with surgery for lumbar spinal disease. RESULTS In total, 131 patients (77.5%, G-group) were satisfied and 38 patients (22.5%, P-group) were dissatisfied with surgery. The 2 groups did not differ significantly in baseline characteristics and surgical data. Postoperative visual analog scale score for low back pain and leg pain were significantly higher in the P-group than in the G-group (low back pain: G-group, 1.7±1.9 vs. P-group, 5.2±2.5, P