Trends in the surgical treatment for metastatic spinal tumor in Japanese administrative data between 2012 and 2020.

BACKGROUND: Both cancer diagnosis/treatment modality and surgical technique for the spine have been developed recently. Nationwide trends in the surgical treatment for metastatic spinal tumors have not been reported in the last decades. This study aimed to examine recent trends in the surgical treatment for spinal metastasis and in-hospital patient outcomes using nationwide administrative hospital discharge data. METHODS: The Diagnosis Procedure Combination database from 2012 to 2020 was used to extract data from patients who underwent surgical procedures for spinal metastasis with the number of non-metastatic spinal surgery at the institutions that have performed metastatic spine surgeries at least one case in the same year. Trends in the surgical treatment for spinal metastasis, patients' demographics, and in-hospital mortality/outcomes were investigated. RESULTS: This study analyzed 10,321 eligible patients with spinal metastasis. The surgical treatment for spinal metastasis increased 1.68 times from 2012 to 2020, especially in fusion surgery, whereas the proportion of metastatic spinal surgery retained with a slight increase in the 2%s. Distributions of the primary site did not change, whereas age was getting older. In-hospital mortality and length of stay decreased over time (9.9-6.8%, p < 0.001; 37-30 days, p < 0.001). Postoperative complication and unfavorable ambulatory retained stable and slightly decreased, respectively. CONCLUSION: During the last decade, surgical treatment for spinal metastasis, especially fusion surgery, has increased in Japan. In-hospital mortality and length of stay decreased. Recent advances in cancer treatment and surgical techniques might influence this trend.

Perioperative complications and cost of posterior decompression with fusion in thoracic spine for ossification of the posterior longitudinal ligament and ossification of the ligamentum flavum -a comparative study using a national inpatient database.

BACKGROUND: Although posterior decompression with fusion (PDF) are effective for treating thoracic myelopathy, surgical treatment has a high risk of various complications. There is currently no information available on the perioperative complications in thoracic ossification of the longitudinal ligament (T-OPLL) and thoracic ossification of the ligamentum flavum (T-OLF). We evaluate the perioperative complication rate and cost between T-OPLL and T-OLF for patients underwent PDF. METHODS: Patients undergoing PDF for T-OPLL and T-OLF from 2012 to 2018 were detected in Japanese nationwide inpatient database. One-to-one propensity score matching between T-OPLL and T-OLF was performed based on patient characteristics and preoperative comorbidities. We examined systemic and local complication rate, reoperation rate, length of hospital stays, costs, discharge destination, and mortality after matching. RESULTS: In a total of 2,660 patients, 828 pairs of T-OPLL and T-OLF patients were included after matching. The incidence of systemic complications did not differ significantly between the T-OPLL and OLF groups. However, local complications were more frequently occurred in T-OPLL than in T-OLF groups (11.4% vs. 7.7% P = 0.012). Transfusion rates was also significantly higher in the T-OPLL group (14.1% vs. 9.4%, P = 0.003). T-OPLL group had longer hospital stay (42.2 days vs. 36.2 days, P = 0.004) and higher medical costs (USD 32,805 vs. USD 25,134, P < 0.001). In both T-OPLL and T-OLF, the occurrence of perioperative complications led to longer hospital stay and higher medical costs. While fewer patients in T-OPLL were discharged home (51.6% vs. 65.1%, P < 0.001), patients were transferred to other hospitals more frequently (47.5% vs. 33.5%, P = 0.001). CONCLUSION: This research identified the perioperative complications of T-OPLL and T-OLF in PDF using a large national database, which revealed that the incidence of local complications was higher in the T-OPLL patients. Perioperative complications resulted in longer hospital stays and higher medical costs.

Action protocol of medical staff for airway obstruction after anterior cervical spine surgery: A systematic review of case reports.

BACKGROUND: Postoperative airway obstruction after anterior cervical spine surgery (ACSS) can be a fatal complication. Occasionally, it rapidly progresses to complete obstruction. There are no established standardized protocols on how medical staff should assess for signs and symptoms, seek help, or facilitate airway management after ACSS to prevent unfavorable events. This study aimed to primarily describe a systematic approach by assessing the signs and treatment outcomes of airway compromise in patients who underwent ACSS. Further, it recommended an action protocol after extubation for medical staff according to patients' symptoms to prevent unfavorable outcomes. METHODS: An extensive literature search was performed on PubMed, Web of Science, and the Cochrane Library to identify case reports, case series, and cohort studies restricted to English and published between January 1990 and March 2023. We included cases that described the signs, symptoms, and treatment of airway obstruction after ACSS. Meanwhile, cases involving complications of other known causes, cases of trauma or occipital-cervical fixation, or those using bone morphogenetic protein were excluded. RESULTS: Twenty cases from 17 studies were obtained, and their study quality was acceptable. Four patients died, and two presented with hypoxic ischemic encephalopathy. Further, five of six patients had fatal complications that initially developed within 7 h after surgery. Then, 9 (69%) of 13 patients with evidence of hematoma (69%) showed initial symptoms within 12 h after surgery. Finally, 9 of 11 patients with early-stage symptoms had favorable outcomes, and patients who developed late-stage symptoms commonly had unfavorable outcomes. CONCLUSION: The early identification of signs and symptoms and immediate treatment are important, particularly within 12 h postoperatively. We suggest a novel action protocol for medical staff according to symptom urgency, which includes the measurement of neck circumference using a string for evaluating neck swelling.

Sub-nanometer scale depth patterning on sapphire crystal by femtosecond soft x-ray laser pulse irradiation.

Damage thresholds and structures on a metal aluminum and an aluminum oxide crystal induced by the soft x-ray free electron laser irradiations were evaluated. Distinctive differences in damage thresholds and structures were observed for these materials. On the aluminum oxide crystal surface, in particular, a novel, to the best of our knowledge, surface processing, which we suggest defining as "peeling," was recognized. Surface structures formed by peeling had extremely shallow patterning of sub-nanometer depth. For the newly observed peeling process, we proposed a scission of chemical bond, i.e., binding energy model, in the crystal.

Deep learning-based prediction model for postoperative complications of cervical posterior longitudinal ligament ossification.

PURPOSE: Postoperative complication prediction helps surgeons to inform and manage patient expectations. Deep learning, a model that finds patterns in large samples of data, outperform traditional statistical methods in making predictions. This study aimed to create a deep learning-based model (DLM) to predict postoperative complications in patients with cervical ossification of the posterior longitudinal ligament (OPLL). METHODS: This prospective multicenter study was conducted by the 28 institutions, and 478 patients were included in the analysis. Deep learning was used to create two predictive models of the overall postoperative complications and neurological complications, one of the major complications. These models were constructed by learning the patient's preoperative background, clinical symptoms, surgical procedures, and imaging findings. These logistic regression models were also created, and these accuracies were compared with those of the DLM. RESULTS: Overall complications were observed in 127 cases (26.6%). The accuracy of the DLM was 74.6 ± 3.7% for predicting the overall occurrence of complications, which was comparable to that of the logistic regression (74.1%). Neurological complications were observed in 48 cases (10.0%), and the accuracy of the DLM was 91.7 ± 3.5%, which was higher than that of the logistic regression (90.1%). CONCLUSION: A new algorithm using deep learning was able to predict complications after cervical OPLL surgery. This model was well calibrated, with prediction accuracy comparable to that of regression models. The accuracy remained high even for predicting only neurological complications, for which the case number is limited compared to conventional statistical methods.

Soft X-ray ptychography system using a Wolter mirror for achromatic illumination optics.

A soft X-ray ptychography system using a Wolter mirror for the illumination optics has been developed. By taking advantage of the achromaticity of the optics, the system is capable of seamlessly imaging at half-period resolution of 50 nm with a broad photon-energy range from 250 eV to 2 keV while maintaining the focal position. Imaging a mammalian cell at various wavelengths was demonstrated, and high-resolution visualization of organelle was achieved. Stereo imaging was also performed with a long working distance of 20 mm. In combination with in-situ/operando and tomographic measurements, this system will be a powerful tool for observing biological and material targets with complex features.

A systematic review and meta-analysis comparing anterior decompression with fusion and posterior laminoplasty for cervical spondylotic myelopathy.

BACKGROUND: The optimal surgical procedure for the treatment of cervical spondylotic myelopathy (CSM) remains controversial because there are few comprehensive studies that have investigated the surgical methods. Therefore, we conducted a systematic review and meta-analysis to evaluate evidence in the literature and to compare the surgical outcomes between anterior decompression with fusion (ADF) and laminoplasty, which are representative procedures for CSM. METHODS: An extensive literature search was performed using PubMed, Embase, and the Cochrane Library to identify comparative studies of ADF and laminoplasty for CSM. The language was restricted to English, and the publication period was from January 2001 to July 2019. We only included studies of CSM and excluded studies that involved patients with ossification of the posterior longitudinal ligament and treatments with posterior instrumented fusion. We extracted outcomes from the studies, such as preoperative and postoperative Japanese Orthopaedic Association (JOA) scores, cervical alignment, surgical complications and reoperation rates. Then, a meta-analysis was performed on these surgical outcomes. RESULTS: Nine studies were obtained, and the quality of the studies was acceptable. In the meta-analysis, the preoperative JOA score was similar between the ADF and laminoplasty groups. The postoperative JOA scores and neurological recovery rates were not different between the ADF and laminoplasty groups. ADF exhibited more favorable results than laminoplasty in terms of postoperative cervical alignment. In contrast, overall complications were more frequently observed in the ADF group than in the laminoplasty group, leading to higher rates of reoperation. However, postoperative neck pain was more frequently observed in the laminoplasty group than in the ADF group. CONCLUSIONS: This systematic review and meta-analysis showed both the merits and shortcomings of ADF and laminoplasty. ADF and laminoplasty showed similar results in terms of neurological recovery. Postoperative cervical lordosis was better preserved with ADF than with laminoplasty. However, ADF was associated with a higher incidence of surgical complications than laminoplasty.

A systematic review and meta-analysis comparing anterior decompression with fusion and posterior laminoplasty for cervical ossification of the posterior longitudinal ligament.

BACKGROUND: The optimal surgical procedure for the treatment of cervical ossification of the posterior longitudinal ligament (OPLL) remains controversial because there are few comprehensive studies investigating the surgical methods. Therefore, we conducted a systematic review and meta-analysis to evaluate evidence in the literature and compare the surgical outcomes of anterior decompression with fusion (ADF) and laminoplasty (LAMP), which are representative procedures for cervical OPLL. METHODS: An extensive literature search was performed using PubMed, Embase, and the Cochrane Library to identify comparative studies of ADF and LAMP for cervical OPLL. The language was restricted to English, and the year of publication was from January 1980 to December 2018. We extracted outcomes from the studies, such as preoperative and postoperative Japanese Orthopaedic Association (JOA) score, cervical alignment, surgical complications and reoperation rate. Then, meta-analysis was performed for these surgical outcomes. RESULTS: Twelve studies were obtained, including 1 prospective cohort study and 11 retrospective cohort studies. In the meta-analysis, neurological recovery rate in JOA score was greater in ADF than in LAMP, especially in patients with a large canal occupying ratio (≥60%) and preoperative kyphotic alignment. ADF also exhibited more favorable results in postoperative cervical alignment. In contrast, operating time and intraoperative blood loss were greater in ADF. Surgical complications were more frequently seen in ADF, leading to higher rates of reoperation. CONCLUSIONS: This systematic review and meta-analysis showed both the merits and shortcomings of ADF and LAMP. ADF resulted in more favorable neurological recovery compared to LAMP, especially for patients with massive OPLL and kyphotic alignment. Postoperative cervical lordosis was also better preserved in ADF. However, ADF was associated with greater surgical invasion and higher incidences of surgical complications.

Intense sub-micrometre focusing of soft X-ray free-electron laser beyond 1016 W†cm-2 with an ellipsoidal mirror.

Intense sub-micrometre focusing of a soft X-ray free-electron laser (FEL) was achieved by using an ellipsoidal mirror with a high numerical aperture. A hybrid focusing system in combination with a Kirkpatrick-Baez mirror was applied for compensation of a small spatial acceptance of the ellipsoidal mirror. With this system, the soft X-ray FEL pulses were focused down to 480 nm × 680 nm with an extremely high intensity of 8.8×1016 W cm-2 at a photon energy of 120 eV, which yielded saturable absorption at the L-edge of Si (99.8 eV) with a drastic increase of transmittance from 8% to 48%.

Full-field microscope with twin Wolter mirrors for soft X-ray free-electron lasers.

We developed a full-field microscope with twin Wolter mirrors for soft X-ray free-electron lasers. The Wolter mirrors for a condenser and an objective were fabricated using an electroforming process with a precisely figured master mandrel. In the imaging system constructed at SACLA BL1, sub-micrometer spatial resolution was achieved at wavelengths of 10.3 and 3.4 nm. Single-shot bright-field images were acquired with a maximum illumination intensity of 7×1014 W/cm2.

Bone Fracture Acute Phase Response-A Unifying Theory of Fracture Repair: Clinical and Scientific Implications.

Bone fractures create five problems that must be resolved: bleeding, risk of infection, hypoxia, disproportionate strain, and inability to bear weight. There have been enormous advancements in our understanding of the molecular mechanisms that resolve these problems after fractures, and in best clinical practices of repairing fractures. We put forth a modern, comprehensive model of fracture repair that synthesizes the literature on the biology and biomechanics of fracture repair to address the primary problems of fractures. This updated model is a framework for both fracture management and future studies aimed at understanding and treating this complex process. This model is based upon the fracture acute phase response (APR), which encompasses the molecular mechanisms that respond to injury. The APR is divided into sequential stages of "survival" and "repair." Early in convalescence, during "survival," bleeding and infection are resolved by collaborative efforts of the hemostatic and inflammatory pathways. Later, in "repair," avascular and biomechanically insufficient bone is replaced by a variable combination of intramembranous and endochondral ossification. Progression to repair cannot occur until survival has been ensured. A disproportionate APR-either insufficient or exuberant-leads to complications of survival (hemorrhage, thrombosis, systemic inflammatory response syndrome, infection, death) and/or repair (delayed- or non-union). The type of ossification utilized for fracture repair is dependent on the relative amounts of strain and vascularity in the fracture microenvironment, but any failure along this process can disrupt or delay fracture healing and result in a similar non-union. Therefore, incomplete understanding of the principles herein can result in mismanagement of fracture care or application of hardware that interferes with fracture repair. This unifying model of fracture repair not only informs clinicians how their interventions fit within the framework of normal biological healing but also instructs investigators about the critical variables and outputs to assess during a study of fracture repair.

Factors associated with the time required for CRP normalization in pyogenic spondylitis: A retrospective observational study.

Background: Treatment for pyogenic spondylitis tends to be prolonged; however, few studies have examined the factors associated with the time required for infection control. Therefore, we analyzed a consecutive cohort of patients to identify factors associated with the time required to control infection in pyogenic spondylitis. This study aimed to clarify the factors linked to the duration necessary for achieving infection control in cases of pyogenic spondylitis, using C-reactive protein (CRP) normalization as an indicator. Methods: In this retrospective observational study, we investigated 108 patients diagnosed with pyogenic spondylitis. We evaluated the number of days from the first visit to CRP normalization; for cases wherein CRP did not normalize, the number of days to the date of final blood sampling was evaluated. In the present study, infection control in pyogenic spondylitis was defined as a CRP falling within the normal range (≤0.14 mg/dL). We performed univariate and multivariate Cox regression analyses to identify various factors associated with the time required for CRP normalization in pyogenic spondylitis. Results: The mean time required for CRP normalization was 148 days. Univariate Cox regression analysis showed that the serum creatinine level, estimated glomerular filtration rate (eGFR), lymphocyte percentage, neutrophil percentage, CRP level, CRP-albumin ratio, and neutrophil-to-lymphocyte ratio were significantly associated with the time required to control infection. Multivariate Cox regression analysis showed that a higher neutrophil percentage, diabetes mellitus, and a lower eGFR were the independent factors associated with a longer infection control time. Conclusions: We found that a higher neutrophil percentage, diabetes mellitus, and a lower eGFR were significantly associated with a longer time for CRP normalization in pyogenic spondylitis. These findings may help identify patients with pyogenic spondylitis who are at a high risk for an extended infection control period.

Detection of Dural Defect Localization Using 4-Dimensional Dynamic Computed Tomography Myelography for Patients with Superficial Siderosis.

BACKGROUND: There are cases of superficial siderosis (SS) with spinal ventral fluid-filled collection in the spinal canal. In our previous study, the balanced steady-state free precession sequence magnetic resonance imaging is useful in identifying the location of dural defects. However, because of its narrow scan area and long scan time, it cannot easily detect the defect location in some patients with small dural defect. In this study, we applied 4-dimensional (4D) dynamic computed tomography (CT) imaging, including time-axis imaging, to myelography using the latest CT imaging equipment, which can perform short-time continuous imaging, to identify the dural defect site. METHODS: Twenty SS patients with ventral fluid-filled collection in the spinal canal (9 males, 11 females; mean age 61.6 years) underwent 4D dynamic CT myelography. A 192-row helical CT (SOMATOM Force, SIEMENS, Munich, Germany) with high-speed scanning capability was used to obtain 9-11 scans per minute at low dose while passing contrast medium into the subarachnoid space. Then, contrast leakage sites were identified. RESULTS: The contrast leakage sites could be identified in all 20 cases: C7/Th1, 2 cases; Th1/2, 5 cases; Th2/3, 9 cases; Th3/4, 1 case; Th5/6, 1 case; Th7/8, 1 case; and Th8/9, 1 case. Eighteen cases underwent surgical operation, and actual dural defects were confirmed at the contrast leakage sites. The mean ± standard deviation of leakage time from contrast agent injection was 19.0 ± 9.2 s. CONCLUSIONS: The 4D dynamic CT myelography can be used to reliably identify the location of spinal fluid leakage. In SS cases, dural defects could be visualized in an average of 19 seconds.

Comparison of Postoperative Complications and Outcomes in Anterior Cervical Spine Surgery: Ossification of the Posterior Longitudinal Ligament Versus Cervical Spondylotic Myelopathy.

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: To compare the frequency of complications and outcomes between patients with ossification of the posterior longitudinal ligament (OPLL) of the cervical spine and those with cervical spondylotic myelopathy (CSM) who underwent anterior surgery. SUMMARY OF BACKGROUND DATA: Anterior cervical spine surgery for OPLL is an effective surgical procedure; however, it is complex and technically demanding compared with the procedure for CSM. Few reports have compared postoperative complications and clinical outcomes after anterior surgeries between the 2 pathologies. METHODS: Among 1434 patients who underwent anterior cervical spine surgery at 3 spine centers within the same spine research group from January 2011 to March 2021, 333 patients with OPLL and 488 patients with CSM were retrospectively evaluated. Demographics, postoperative complications, and outcomes were reviewed by analyzing medical records. In-hospital and postdischarge postoperative complications were investigated. Postoperative outcomes were evaluated 1 year after the surgery using the Japanese Orthopaedic Association score. RESULTS: Patients with OPLL had more comorbid diabetes mellitus preoperatively than patients with CSM ( P <0.001). Anterior cervical corpectomies were more often performed in patients with OPLL than in those with CSM (73.3% and 14.5%). In-hospital complications, such as reoperation, cerebrospinal fluid leak, C5 palsy, graft complications, hoarseness, and upper airway complications, occurred significantly more often in patients with OPLL. Complications after discharge, such as complications of the graft bone/cage and hoarseness, were significantly more common in patients with OPLL. The recovery rate of the Japanese Orthopaedic Association score 1 year postoperatively was similar between patients with OPLL and those with CSM. CONCLUSION: The present study demonstrated that complications, both in-hospital and after discharge following anterior spine surgery, occurred more frequently in patients with OPLL than in those with CSM.

Effect of vitamin D deficiency on surgical outcomes of degenerative cervical myelopathy.

Background: Due to its association with bone metabolic status and muscle strength/mass, vitamin D deficiency has the potential to affect neurological symptom recovery after surgery for degenerative cervical myelopathy (DCM). However, few studies have investigated the effects of vitamin D deficiency (serum 25(OH)D <20 ng/mL) on surgical outcomes in DCM patients. Herein, we investigated the prevalence of vitamin D deficiency in patients with DCM, and determined whether vitamin D deficiency affects surgical outcomes for DCM. Methods: In this retrospective observational study we assessed the recovery rate 1 year after surgery in 91 patients diagnosed with DCM who underwent surgery. First, we analyzed the correlation between vitamin D levels and various background factors. Then, patients were divided into 2 groups according to vitamin D sufficiency, and univariate analysis was performed on vitamin D and surgical outcomes. Finally, Spearman correlation analyses were performed to identify factors correlated with recovery rate after surgery for DCM. Results: The average Japanese Orthopedic Association score for the assessment of cervical myelopathy (C-JOA score) improved postoperatively. Age was positively correlated with vitamin D levels, and parathyroid hormone levels were negatively correlated with vitamin D levels. Among the 91 patients, 79.1% of patients were diagnosed with vitamin D deficiency. No significant differences in recovery rate were found between the vitamin D-deficient and vitamin D-sufficient groups. Finally, the Spearman correlation analysis showed a positive correlation between the preoperative C-JOA motor dysfunction score in the lower extremities and the recovery rate, while age demonstrated a negative correlation with recovery rate. Conclusions: No association was found between vitamin D deficiency and clinical outcomes after surgery for DCM. The results of this study do not support the need to normalize vitamin D levels for achieving neurological improvements in patients with DCM.

Augmented Reality Support for Anterior Decompression and Fusion Using Floating Method for Cervical Ossification of the Posterior Longitudinal Ligament.

Anterior decompression and fusion (ADF) using the floating method for cervical ossification of the posterior longitudinal ligament (OPLL) is an ideal surgical technique, but it has a specific risk of insufficient decompression caused by the impingement of residual ossification. Augmented reality (AR) support is a novel technology that enables the superimposition of images onto the view of a surgical field. AR technology was applied to ADF for cervical OPLL to facilitate intraoperative anatomical orientation and OPLL identification. In total, 14 patients with cervical OPLL underwent ADF with microscopic AR support. The outline of the OPLL and the bilateral vertebral arteries was marked after intraoperative CT, and the reconstructed 3D image data were transferred and linked to the microscope. The AR microscopic view enabled us to visualize the ossification outline, which could not be seen directly in the surgical field, and allowed sufficient decompression of the ossification. Neurological disturbances were improved in all patients. No cases of serious complications, such as major intraoperative bleeding or reoperation due to the postoperative impingement of the floating OPLL, were registered. To our knowledge, this is the first report of the introduction of microscopic AR into ADF using the floating method for cervical OPLL with favorable clinical results.

Risk Factors for Postoperative Unfavorable Ambulatory Status After Spinal Surgery for Metastatic Spinal Tumor.

STUDY DESIGN: A retrospective comparative study. OBJECTIVE: This study aimed to investigate factors associated with postoperative unfavorable ambulatory status following surgery for metastatic spinal tumors using a nationwide in-hospital database. SUMMARY OF BACKGROUND DATA: Surgical treatment for metastatic spinal tumors can improve the ambulatory status and quality of life. However, some patients fail to regain the ability to walk, thereby resulting in poor quality of life. No large-scale study has previously evaluated factors associated with postoperative poor ambulatory status in this clinical context. MATERIALS AND METHODS: The Diagnosis Procedure Combination database from 2018 to 2019 was used to extract data from patients who underwent surgical procedures for spinal metastasis. Postoperative unfavorable ambulatory status was defined as (1) nonambulatory at discharge or (2) a decreased mobility score of the Barthel Index between admission and discharge. Multivariable logistic regression was used to evaluate factors associated with postoperative unfavorable ambulatory status while adjusting for confounders. RESULTS: This study analyzed 1786 eligible patients. Of whom, 1061 (59%) patients were ambulatory on admission and 1249 (70%) on discharge. Postoperative unfavorable ambulatory status was observed in 597 (33%) patients, with a significantly lower rate of discharge to home (41%/81%, P <0.001) and a longer postoperative hospital stay (46.2 days/31.4 days, P <0.001). Multivariable regression analysis revealed male sex [odds ratio (OR): 1.43, P =0.002], laminectomy without fusion (OR: 1.55, P =0.034), Charlson Comorbidity Index of ≥7 (OR: 1.37, P =0.014), and preoperative nonambulatory status (OR: 6.61, P <0.001) as factors associated with postoperative unfavorable ambulatory status. CONCLUSIONS: Our large-scale database analysis revealed that 33% of patients experienced unfavorable ambulatory status following spinal metastasis surgery. Laminectomy without fusion and preoperative nonambulatory status were among several factors influencing the prospect of unfavorable ambulatory status following surgery.

Factors Associated With Nonunion After Cervical Fusion Surgery.

Background Bony fusion is a critical factor in the outcome of cervical spinal fusion surgery. While several factors have been proposed to affect bony fusion, their relative importance remains unclear. This study aimed to investigate the factors associated with bony fusion after cervical spinal fusion surgery. Methods We retrospectively evaluated the significance of the various factors on bone fusion after cervical fusion surgery. Then, multivariate logistic regression analyses were performed to determine the independent factors associated with bony fusion. A receiver operating characteristic (ROC) analysis was performed to evaluate the cutoff threshold. Results This study included a total of 52 patients with a mean age of 64 years. Among them, 28 (54%) were male, and 39 (75.0%) achieved bony fusion. The multivariate logistic regression analysis showed that preoperative intact parathyroid hormone (PTH) levels (odds ratio, 1.04; 95% confidence interval, 1.01-1.08; p-value = 0.02) and hemoglobin A1c (HbA1c) levels (odds ratio, 2.87; 95% confidence interval, 1.07-8.74; p-value = 0.04) were significant factors associated with bony fusion after cervical fusion surgery. The optimum cutoff values of intact PTH and HbA1c were 63.5 pg/mL and 6.2%, respectively. Conclusions This study identified preoperative intact PTH and HbA1c as significant factors associated with bony fusion after cervical fusion surgery. These biomarkers can be used to identify patients at higher risk of nonunion to optimize patient conditions and guide preoperative and postoperative management strategies.

Figure correction of a Wolter mirror master mandrel by organic abrasive machining.

In this study, figure correction of a master mandrel of a Wolter mirror by organic abrasive machining (OAM) was demonstrated. In OAM, a flow of slurry, dispersed with organic particles, locally removes the surface of a workpiece in contact with a rotating machining tool. A computer-controlled machining system was used to perform the selective removal of a fused silica surface at a spatial resolution of 200 µm. A master mandrel of a Wolter mirror for soft x-ray microscopes was fabricated with a figure accuracy of <1 nm root mean square, which is sufficient for diffraction-limited imaging at a wavelength of 10 nm.

Residual Neuropathic Pain in Postoperative Patients With Cervical Ossification of Posterior Longitudinal Ligament.

STUDY DESIGN: A prospective multi-institutional observational study. OBJECTIVE: To investigate and identify risk factors for residual neuropathic pain after surgery in patients with cervical ossification of posterior longitudinal ligament (c-OPLL). SUMMARY OF BACKGROUND DATA: Patients with c-OPLL often require surgery for numbness and paralysis of the extremities; however, postoperative neuropathic pain can considerably deteriorate their quality of life. METHODS: Out of 479 patients identified from multicenter c-OPLL registries between 2014 and 2017, 292 patients who could be followed up for 2 years postoperatively were reviewed, after excluding patients with nervous system comorbidities. Demographic details; medical history; radiographic factors including the K-line, spinal canal occupancy rate of OPLL, cervical kyphosis angle, and presence of spinal cord myelomalacia; preoperative Japanese Orthopaedic Association (JOA) score; surgical procedure (fusion or decompression surgery); postoperative neurological deterioration; and the visual analogue scale for pain and numbness in the upper extremities (U/E) or trunk/lower extremities (L/E) at baseline and at 2 years postoperatively were assessed. Patients were grouped into residual and non-residual groups based on a postoperative visual analogue scale ≥40 mm. Risk factors for residual neuropathic pain were evaluated by multiple logistic regression analysis. RESULTS: The prevalence of U/E and L/E residual pain in postoperative c-OPLL patients was 51.7% and 40.4%, respectively. The U/E residual group had a poor preoperative JOA score and longer illness duration, and fusion surgery was more common in the residual group than in non-residual group. The L/E residual group was older with a poorer preoperative JOA score. On multivariate analysis, risk factors for U/E residual pain were long illness duration and poor preoperative JOA score, whereas those for L/E residual pain were age and poor preoperative JOA score. CONCLUSIONS: The risk factors for residual spinal neuropathic pain after c-OPLL surgery were age, long duration of illness, and poor preoperative JOA score. LEVEL OF EVIDENCE: IV.