Longitudinal impact of multi-segment spinal fixation surgery on mobility status and clinical outcomes in adult spinal deformity: a multicenter retrospective study.

PURPOSE: To investigate changes in postoperative mobility status in patients with ASD, and the determining factors that influence these changes and their impact on clinical outcomes, including the rate of home discharge and long-term mobility. METHODS: A total of 299 patients with ASD who underwent multi-segment posterior spinal fusion were registered in a multi-center database were investigated. Patient mobility status was assessed using walking aids and classified into five levels (1: independent, 2: cane, 3: walker, 4: assisted, and 5: wheelchair) preoperatively, at discharge, and after 2 years. We determined improvements or declines in the patient's mobility based on changes in the classification levels. The analysis focused on the factors contributing to the deterioration of postoperative mobility. RESULTS: Two years postoperatively, 87% of patients maintained or improved mobility. However, 27% showed decreased mobility status at discharge, associated with a lower rate of home discharge (49% vs. 80% in the maintained mobility group) and limited improvement in mobility status (35% vs. 5%) after 2 years. Notably, postoperative increases in thoracic kyphosis (7.0 ± 12.1 vs. 2.0 ± 12.4°, p = 0.002) and lower lumbar lordosis (4.2 ± 13.1 vs. 1.8 ± 12.6°, p = 0.050) were substantial factors in mobility decline. CONCLUSION: Postoperative mobility often temporarily decreases but generally improves after 2 years. However, an overcorrection in sagittal alignment, evidenced by increased TK, could detrimentally affect patients' mobility status. Transient mobility decline associated with overcorrection may require further rehabilitation or hospitalization. Further studies are required to determine the biomechanical effects of surgical correction on mobility.

Preoperative low Hounsfield units in the lumbar spine are associated with postoperative mechanical complications in adult spinal deformity.

PURPOSE: To determine the most valid bone health parameter to predict mechanical complications (MCs) following surgery for adult spinal deformity (ASD). METHODS: This multicenter study retrospectively examined the records of patients who had undergone fusion of three or more motion segments, including the pelvis, with a minimum two-year follow-up period. Patients with moderate and severe global alignment and proportion scores were included in the study and divided into two groups: those who developed MCs and those who did not. Bone mineral density (BMD) of the lumbar spine and femoral neck was measured using dual-energy X-ray absorptiometry, and Hounsfield units (HUs) were measured in the lumbar spine on computed tomography. Radiographic parameters were evaluated preoperatively, immediately after surgery, and at final follow-up. RESULTS: Of 108 patients, 30 (27.8%) developed MCs, including 26 cases of proximal junctional kyphosis/failure, 2 of distal junctional failure, 6 of rod fracture, and 11 reoperations. HUs were significantly lower in patients who experienced MCs (113.7 ± 41.1) than in those who did not (137.0 ± 46.8; P = 0.02). BMD did not differ significantly between the two groups. The preoperative and two-year postoperative global tilt, as well as the immediately postoperative sagittal vertical axis, were significantly greater in patients who developed MCs than in those who did not (P = 0.02, P < 0.01, and P = 0.01, respectively). CONCLUSION: Patients who experienced MCs following surgery for ASD had lower HUs than those who did not. HUs may therefore be more useful than BMD for predicting MCs following surgery for ASD.

Does global spinal alignment affect the use of walking aids after multi-segment spinal fixation for patients with ASD? A multicenter retrospective study.

PURPOSE: This study aimed to clarify the relation between global spinal alignment and the necessity of walking aid use in patients with adult spinal deformity (ASD) and to investigate the impact of spinal fixation on mobility status after surgery. METHODS: In total, 456 older patients with ASD who had multi-segment spinal fixation surgery and were registered in a multi-center database were investigated. Patients under 60 years of age and those unable to walk preoperatively were excluded. Patients were classified by their mobility status into the independent, cane, and walker groups. Comparison analysis was conducted using radiographic spinopelvic parameters and the previously reported global spine balance (GSB) classification. In addition, preoperative and 2 years postoperative mobility statuses were investigated. RESULTS: Of 261 patients analyzed, 66 used walking aids (canes, 46; walkers, 20). Analysis of preoperative radiographical parameters showed increased pelvic incidence and pelvic incidence-lumbar lordosis mismatch in the walker group and increased sagittal vertebral axis in the cane and walker groups versus the independent group. Analysis of GSB classification showed a higher percentage of walker use in those with severe imbalance (grade 3) in the sagittal classification but not in the coronal classification. While postoperative radiographical improvements were noted, there was no significant difference in the use of walking aids before and 2 years after surgery (P = 0.085). CONCLUSION: A significant correlation was found between "sagittal" spinal imbalance and increased reliance on walking aids, particularly walkers. However, the limitation of improvement in postoperative mobility status suggested that multiple factors influence the mobility ability of elderly patients with ASD.

Laterality of lumbar disc herniation.

BACKGROUND: Lumbar disc herniation (LDH) is most common in men aged 20-40 at the L4/5 level; however, left-right differences have not been reported. Improving our understanding of left- and right-side LDH may facilitate the estimation of mechanical load on intervertebral discs. Here, we assessed left-right differences in LDH via a retrospective analysis of LDH cases. METHODS: Among 10,972 surgical cases of LDH identified in the Nagoya Spine Group database, 2899 in which right- and left-LDH sides were observable in a single vertebral segment were identified (mean age 46.3 ± 16.6 years, 2028 males). The following characteristics of patients with right- and left-LDH were compared: age, LDH level, surgical technique, operative time, blood loss, length of hospital stay, preoperative Japan Orthopaedic Association (JOA) score, and JOA recovery rate. RESULTS: LDH occurred on the right and left sides in 1358 and 1541 patients, respectively, with patients with right-side LDH significantly older than those with left (47.9 ± 16.6 versus 45.0 ± 16.5, respectively; p < 0.001). No between-group differences in sex, age, LDH level, surgical technique, operative time, blood loss, length of hospital stay, preoperative JOA score, or JOA recovery rate were observed. The occurrence of right-side LDH increased with age, occurring in 42.7%, 45.1%, 49.9%, and 54.7% of patients aged 10-29, 30-49, 50-69, and 70-89 years, respectively. CONCLUSION: Left-side LDH was observed more frequently than right; however, right-side LDH incidence increased with age. No significant between-group differences regarding symptoms, treatments, or outcomes were observed.

Vertebral Endplate Concavity in Lateral Lumbar Interbody Fusion: Tapered 3D-Printed Porous Titanium Cage versus Squared PEEK Cage.

Background and Objectives: To prevent postoperative problems in extreme lateral interbody fusion (XLIF), it is critical that the vertebral endplate not be injured. Unintentional endplate injuries may depend on the cage. A novel porous titanium cage for XLIF has improved geometry with a tapered tip and smooth surface. We hypothesized that this new cage should lead to fewer endplate injuries. Materials and Methods: This retrospective study included 32 patients (mean 74.1 ± 6.7 years, 22 females) who underwent anterior and posterior combined surgery with XLIF for lumbar degenerative disease or adult spinal deformity from January 2018 to June 2022. A tapered 3D porous titanium cage (3DTi; 11 patients) and a squared PEEK cage (sPEEK; 21 patients) were used. Spinal alignment values were measured on X-ray images. Vertebral endplate concavity (VEC) was defined as concavity ≥ 1 mm of the endplate on computed tomography (CT) images, which were evaluated preoperatively and at 1 week and 3 months postoperatively. Results: There were no significant differences in the patient demographic data and preoperative and 3-month postoperative spinal alignments between the groups. A 3DTi was used for 25 levels and an sPEEK was used for 38 levels. Preoperative local lordotic angles were 4.3° for 3DTi vs. 4.7° for sPEEK (p = 0.90), which were corrected to 12.3° and 9.1° (p = 0.029), respectively. At 3 months postoperatively, the angles were 11.6° for 3DTi and 8.2° for sPEEK (p = 0.013). VEC was present in 2 levels (8.0%) for 3DTi vs. 17 levels (45%) for sPEEK (p = 0.002). After 3 months postoperatively, none of the 3DTi had VEC progression; however, eight (21%) levels in sPEEK showed VEC progression (p = 0.019). Conclusions: The novel 3DTi cage reduced endplate injuries by reducing the endplate load during cage insertion.

Seasonal variation in incidence and causal organism of surgical site infection after PLIF/TLIF surgery: A multicenter study.

BACKGROUND: Postoperative SSI is a common and potentially serious complication in spine surgery. Seasonal variation occurs in rates of nosocomial infection, with higher rates found in the summer, during which hot, humid conditions may be optimal for proliferation of bacteria. This might also influence the rate of SSI. The purpose of the study was to examine seasonal variation in SSI after PLIF/TLIF surgery, including relationships with experience of surgeons and causal organisms. METHODS: Cases with SSI after PLIF/TLIF surgery at 10 facilities between January 1, 2012, and December 31, 2014 were retrieved from a database. Infection was defined based on CDC guidelines for SSIs. Patients were followed for at least two years after surgery. Surgeries were examined in spring (April-June), summer (July-September), autumn (October-December), and winter (January-March). Seasonal variation and other factors with a potential association with SSIs were evaluated. RESULTS: A total of 1174 patients (607 males, 567 females) who underwent PLIF/TLIF surgery were identified. The operations were PLIF (n = 667), TLIF (n = 443), MIS-PLIF (n = 27), and MIS-TLIF (n = 37). The total SSI rate for the 2-year period was 2.5% (29/1174), and the 2-year average SSI rates for surgeries in each season were spring, 2.6% (7/266); summer, 3.9% (13/335); fall, 1.3% (4/302); winter, 1.8% (5/271). The SSI rate was significantly higher in summer than non-summer (3.9% vs. 1.9%, p < 0.05). SSIs were caused by a variety of pathogens, including Gram-positive cocci, and Staphylococcus aureus was the most common pathogenic organism to cause SSI. CONCLUSION: Seasonality should be taken into account in strategies for SSI prevention, with particular attention on mitigation of increased temperature and humidity in the summer and on infection caused by Gram-positive cocci and S. aureus.

Reoperation within 2 years after lumbar interbody fusion: a multicenter study.

PURPOSE: Posterior lumbar interbody fusion (PLIF)/transforaminal lumbar interbody fusion (TLIF) can have complications that require reoperation. The goal of the study was to identify risk factors for reoperation within 2 years after PLIF/TLIF. METHODS: A retrospective analysis of a prospective multicenter database was performed for patients who underwent PLIF/TLIF. A total of 1363 patients (689 males and 674 females) were identified, with an average age of 65.9 years old. Comorbidities, perioperative ASA grade, and operative factors were compared between patients with and without reoperation. Risk factors for reoperation were identified in multivariate logistic analysis. RESULTS: There were 38 reoperations within 2 years after PLIF/TLIF (2.8%). The original surgical procedures were open PLIF (n = 26), open TLIF (n = 10), and minimally invasive surgery (n = 2). Reoperation was due to adjacent segment degeneration (ASD) (n = 10), surgical site infection (SSI) (n = 9), screw misplacement (n = 6), postoperative epidural hematoma (n = 6), pseudoarthrosis (n = 4), and cage protrusion (n = 3). Number of levels fused and dural tear were significantly associated with reoperation. In analysis of complications requiring reoperation, SSI was related to diabetes mellitus and dural tear, and postoperative epidural hematoma was related to fusion of two or more levels, EBL, and operation time. In multivariate logistic regression, fusion of two or more levels (HR 2.19) was significantly associated with reoperation. CONCLUSION: Surgical invasiveness, as reflected by number of fused levels, operation time, EBL and dural tear, was associated with reoperation. Fusion of two or more levels is a strong risk factor for reoperation within 2 years after initial PLIF/TLIF. These slides can be retrieved under Electronic Supplementary Material.

Fatal case of cervical blunt vascular injury with cervical vertebral fracture: a case report.

Blunt cerebrovascular injury (BCVI) is usually caused by neck trauma that predominantly occurs in high-impact injuries. BCVI may occur due to damage to both the vertebral and carotid arteries, and may be fatal in the absence of appropriate treatment and early diagnosis. Here, we describe a case of cerebral infarction caused by a combination of a lower cervical spinal fracture and traumatic injury to the carotid artery by a direct blunt external force in a 52-year-old man. Initially, there was no effect on consciousness, but 6 hours later loss of consciousness occurred due to traumatic dissection of the carotid artery that resulted in a cerebral infarction. Brain edema was so extensive that decompression by emergency craniectomy and internal decompression were performed by a neurosurgeon, but with no effect, and the patient died on day 7. This is a rare case of cerebral infarction caused by a combination of a lower cervical spinal fracture and traumatic injury to the carotid artery. The case suggests that cervical vascular injury should be considered in a patient with a blunt neck trauma and that additional imaging should be performed.

Tuberculous meningitis with dementia as the presenting symptom after intramedullary spinal cord tumor resection.

Early-stage TB meningitis has no specific symptoms in patients, potentially leading to delayed diagnosis and consequently worsening prognosis. The authors present the fatal case with a delayed diagnosis of tuberculous (TB) meningitis with dementia as the presenting symptom after intramedullary spinal cord tumor resection. The medical records, operative reports, and radiographical imaging studies of a single patient were retrospectively reviewed. A 77-year-old man who underwent thoracic intramedullary hemangioblastoma resection for 2 times. The postoperative course was uneventful, but 1.5 months after surgery, the patient suffered from dementia with memory loss and diminished motivation and speech in the absence of a fever. No abnormalities were detected on blood test, brain computed tomography and cerebrospinal fluid (CSF) analysis. A sputum sample was negative for Mycobacterium tuberculosis in the QuantiFERON®-TB Gold (QFT-G) In-Tube Test and the tuberculin skin test was also negative. The patient was diagnosed with senile dementia by a psychiatrist. However, the patient's symptoms progressively worsened. Despite the absence of TB meningitis findings, we suspected TB meningitis from the patient's history, and administered a four-drug regimen. However the patient died 29 days after admission, subsequently M. tuberculosis was detected in the CSF sample. This case is a rare case of TB meningitis initially mistaken for dementia after intramedullary spinal cord tumor resection. Symptoms of dementia after intramedullary spinal cord tumor resection should first be suspected as one of TB meningitis, even if the tests for meningitis are negative. We propose that anti-tuberculosis therapy should be immediately initiated in cases of suspected TB meningitis prior to positive identification on culture.

Hyperamylasemia and pancreatitis following posterior spinal surgery.

BACKGROUND: Postoperative pancreatitis has primarily been reported as a complication of abdominal surgery, but there are some case reports of postoperative pancreatitis after spinal surgery. The objective of this study was to investigate a case series of hyperamylasemia and pancreatitis following posterior spinal surgery. METHODS: The serum amylase level was measured following posterior spinal surgery in the prone position. Patients were divided into groups with a normal serum amylase level (0-125 IU/L) and with hyperamylasemia (>125 IU/L), based on the upper limit of normal of 125 IU/L in our institution. Relationships among preoperative factors, perioperative factors, and the serum amylase level were investigated. RESULTS: Hyperamylasemia (serum amylase >125 IU/L) following posterior spinal surgery was found in 92 cases (35 %). Among perioperative factors, intraoperative estimated blood loss (EBL) and operating time were significantly higher in patients with high serum amylase than in patients with normal serum amylase (P < 0.01). In a multivariate regression model, intraoperative EBL (OR 1.001, 95 % CI 1.000-1.002; P = 0.001) and operation time (OR 1.006, 95 % CI 1.003-1.009; P = 0.006) were significantly associated with postoperative pancreatitis. Serum amylase levels of ≥ 5 times the upper limit of normal were found in six cases. Five of these cases were asymptomatic and one was caused by severe pancreatitis. CONCLUSIONS: In our case series, intraoperative blood loss caused a rise in the serum amylase level following posterior spinal surgery. Thus, this level should be carefully monitored after spinal surgery with significant blood loss. Clinical symptoms of pancreatitis, such as abdominal pain and vomiting, should also be monitored following spinal surgery.

Appropriate timing of surgical intervention for the proximal type of cervical spondylotic amyotrophy.

PURPOSE: The purposes of this study were to evaluate the clinical outcome after surgical treatment of patients with the proximal type of cervical spondylotic amyotrophy (CSA) and to explore the appropriate timing for surgical intervention. MATERIALS AND METHODS: A retrospective review was performed on a consecutive cohort of 41 patients who underwent surgical treatment for the proximal type of CSA between 1995 and 2011 at the Nagoya Spine Group Hospitals. We collected information regarding age, type of muscle atrophy, preoperative and final manual muscle test, duration of symptoms, high-intensity areas on T2-weighted MRI images, low-intensity areas on T1-weighted MRI images, levels of spinal canal stenosis, the compression lesion site, cervical kyphosis and surgical procedures (laminoplasty, anterior spinal fusion and posterior spinal fusion). Univariate analyses and multivariate logistic regression analysis were performed to identify correlates of a poor outcome. To explore the appropriate timing for performing surgery, we analyzed the data using receiver operating characteristic (ROC) analysis. RESULTS: The duration of CSA symptoms was 11.6 months on average. The surgical results were excellent for 25 patients, good for six, fair for nine and poor for one. On multivariate logistic regression analysis, the duration of symptoms was statistically associated with a poor surgical outcome (OR 1.393, p = 0.011). ROC analysis demonstrated that 4.3 months from the onset of CSA symptoms was the appropriate time to undergo surgery. CONCLUSIONS: Our results indicate that we should recommend surgical intervention to patients with the proximal type of CSA within about 4 months after the onset of symptoms if conservative treatment has not been successful.

Characterization of the proteinaceous skeletal organic matrix from the precious coral Corallium konojoi.

The Japanese red and pink corals are known to be precious because of their commercial value resulting from their use in ornaments, jewelry, and medicine. Precious corals are very interesting models for biomineralization studies and possess two different skeletal structures: an axial skeleton and an endoskeleton (sclerites). Although it has long been known that the organic matrix proteins existing in coral skeletons are critical for the oriented precipitation of CaCO3 crystals, these proteins in moderate deep-sea Japanese precious corals remain uncharacterized. Therefore, in this study, we performed skeletal whole proteome analyses using 1D and 2D electrophoresis, nano-LC, and MALDI-TOF-TOF MS. We identified a total of 147 functional coral skeletal organic matrix proteins (120 from the sclerites and 36 from the axial skeleton), including two calcium-binding calmodulin. Among the organic matrix proteins identified, nine key proteins are highly typical and common in both skeletons. Strong glycosylation activity, which is essential for skeletal formation in calcifying organisms, was detected in both skeletons. This work demonstrates unique biomineralization-related proteins in precious corals and provides the first description of the major proteinaceous components of CaCO3 minerals in precious corals, enabling the comparative investigation of biocalcification in other octocorals.

Volumetric change in interbody bone graft after posterior lumbar interbody fusion (PLIF): a prospective study.

PURPOSE: The purpose of this study is to quantify the change in the volume of the interbody bone graft after the PLIF and monitor the change over time for subsequent analysis. METHODS: The 114 cases were selected as the subjects of this study. The observation period was for 5 years following the surgery. The volume of the bone graft in the interbody space was calculated by summing up the cross-sectional area of the bone graft on each axial image multiplied by the height (2 mm) (the volume of the two cages was excluded). The volume ratio (%) = (bone graft volume)/(total volume of the interbody space - cage volume) was used for the purpose of evaluation. RESULTS: The volumetric change of the bone graft was 51 % (3 months), 53 % (6 months), 54 % (1 year), 55 % (2 years), 59 % (3 years), 62 % (4 years), and 72 % (5 years), indicating a continued increase up to the 5-year mark. In particular, a significant increase was observed from the second year as compared with the previous years' result. Additionally, the volumetric increase from the second year to the fifth year was significantly higher than that before the second year. CONCLUSIONS: The post-PLIF volumes of interbody bone grafts exhibited increases particularly from the second to fifth years after the procedure. Even the elderly and those with poor bone qualities can expect to have volumetric increases over time. Sufficient interbody space should be secured for accommodating bone grafts by intraoperative reduction, wherever possible.

Recurrence of solitary fibrous tumor of the cervical spinal cord.

Solitary fibrous tumor (SFT) mostly originates from the pleura because of proliferation of fibroblast cells. It is extremely rare for the tumor to originate from the spinal cord. Here, we report a rare case of SFT in the spinal cord that recurred repeatedly and progressed from intramedullary to extramedullary. A 40-year-old man underwent C4-5 intramedullary and extramedullary tumor resection in another hospital. Eighteen years later, he experienced symptoms of myelopathy because of tumor recurrence; therefore, he consulted with our hospital and underwent tumor resection again. During surgery, we found that the tumor had an intramedullary and extramedullary location. Only partial resection was possible because of intraoperative deterioration in the compound motor action potential (CMAP). After resection, the pathological diagnosis was SFT. The postoperative course was good. However, two years later, a third tumor resection was required because of dysuria and tumor growth. In this surgery, total resection of the tumor was possible without intraoperative deterioration of the CMAP. The tumor has not subsequently recurred. However, SFT recurrence is relatively common and careful follow-up is required for early detection of recurrence, even after successful removal of the tumor.

Radiologic evaluation after posterior instrumented surgery for thoracic ossification of the posterior longitudinal ligament: union between rostral and caudal ossifications.

STUDY DESIGN: Retrospective clinical study. OBJECTIVE: To investigate, using multislice CT images, how thoracic ossification of the posterior longitudinal ligament (OPLL) changes with time after thoracic posterior fusion surgery. SUMMARY OF BACKGROUND DATA: Few studies have evaluated thoracic OPLL preoperatively and post using computed tomography (CT). METHODS: The subjects included 19 patients (7 men and 12 women) with an average age at surgery of 52 years (38-66 y) who underwent indirect posterior decompression with corrective fusion and instrumentation at our institute. Minimum follow-up period was 1 year, and averaged 3 years 10 months (12-120 mo). Using CT images, we investigated fusion range, preoperative and postoperative Cobb angles of thoracic fusion levels, intraoperative and postoperative blood loss, operative time, hyperintense areas on preoperative MRI of thoracic spine and thickness of the OPLL on the reconstructed sagittal, multislice CT images taken before the operation and at 3 months, 6 months and 1 year after surgery. The basic fusion area was 3 vertebrae above and below the OPLL lesion. RESULTS: The mean operative time was 7 hours and 48 min (4 h 39 min-10 h 28 min), and blood loss was 1631 mL (160-11,731 mL). Intramedullary signal intensity change on magnetic resonance images was observed at the most severe ossification area in 18 patients. Interestingly, the rostral and caudal ossification regions of the OPLLs, as seen on sagittal CT images, were discontinuous across the disk space in all patients. Postoperatively, the discontinuous segments connected in all patients without progression of OPLL thickness by 5.1 months on average. CONCLUSIONS: All patients needing surgery had discontinuity across the disk space between the rostral and caudal ossified lesions as seen on CT. This discontinuity was considered to be the main reason for the myelopathy because a high-intensity area on magnetic resonance imaging was seen in 18 of 19 patients at the same level. Rigid fixation with instrumentation may allow the discontinuous segments to connect in patients without a concomitant thickening of the OPLL.

Atlantoaxial rotatory fixation in a child after bilateral otoplastic surgery.

Atlantoaxial rotatory fixation (AARF), which is a dislocation or subluxation of the atlantoaxial joint, is a well-recognized condition in children. We present a case of AARF after otoplastic surgery for bilateral cryptotia performed by plastic surgeons. The pediatric patient presented with neck pain and torticollis after the surgery, and an orthopedic surgeon diagnosed AARF. The patient was treated successfully with conservative treatment incorporating mild manual manipulation, neck traction, and a collar for 1.5 months. Physicians should consider the possibility of AARF when a patient presents with neck pain and torticollis after otoplastic surgery; diagnosis and treatment should be started immediately.

Acute pancreatitis after spine surgery: a case report and review of literature.

Although acute postoperative pancreatitis is a relatively frequent complication after open biliary tract surgery and gastric surgery, acute pancreatitis after spine surgery is a rare complication. We report the first case of acute pancreatitis after posterior lumbar interbody fusion (PLIF) for spondylolisthesis that resolved with conservative treatment. A 53-year-old female patient received a PLIF from L3 to L5. The patient presented with persistent mild abdominal pain, nausea and vomiting several hours after the surgery. An abdominal CT revealed swelling of the head of the pancreas and free fluid around the pancreas. A gastroenterologist diagnosed acute pancreatitis and prescribed nafamostat mesilate, antibiotics and intravenous fluid therapy. The patient recovered gradually, and clinical symptoms disappeared. At 6 months after the operation, she had experienced no recurrence of abdominal symptoms, and solid spinal fusion was achieved. In previous studies, acute pancreatitis was reported as a complication after spine surgery for various spine diseases such as scoliosis and lumbar disorders. The procedures performed included anterior/posterior scoliosis surgery and anterior/posterior lumbar fusion surgery. We must consider the possibility of acute pancreatitis when unusual abdominal symptoms with elevated serum amylase levels occur after spine surgery. Prompt diagnosis and supportive therapy are essential to minimize morbidity and mortality.

Mechanism of denitrification in subsurface-dammed Ryukyu limestone aquifer, southern Okinawa Island, Japan.

Denitrification crucially regulates the attenuation of groundwater nitrate and is unlikely to occur in a fast-flowing aquifer such as the Ryukyu limestone aquifer in southern Okinawa Island, Japan. However, evidences of denitrification have been observed in several wells within this region. This study analyzed environmental isotopes (δ15NNO3 and ẟ18ONO3) to derive the rationale for denitrification at this site. Additionally, the presence of two subsurface dams in the study area may influence the processes involved in nitrate attenuation. Herein, we analyzed 150 groundwater samples collected spatially and seasonally to characterize the variations in the groundwater chemistry and stable isotopes during denitrification. The values of δ15NNO3 and δ18ONO3 displayed a progressive trend up to +59.7 ‰ and + 21 ‰, respectively, whereas the concentrations of NO3--N decreased to 0.1 mg L-1. In several wells, the enrichment factors of δ15NNO3 ranged from -6.6 to -2.1, indicating rapid denitrification, and the δ15NNO3 to δ18ONO3 ratios varied from 1.3:1 to 2:1, confirming the occurrence of denitrification. Denitrification intensively proceeds under conditions of depleted dissolved oxygen concentrations (<2 mg L-1), sluggish groundwater flow with longer residence times, high concentrations of dissolved organic carbon (>1.2 mg L-1), and low groundwater levels during the dry season with precipitation rates of <100 mm per month (Jun-Sep). SF6 analysis indicated the exclusive occurrence of denitrification in specific wells with groundwater residence times exceeding 30 years. These wells are located in close proximity to the major NE-SW fault system in the Komesu area, where the hydraulic gradient was below 0.005. Detailed geological and lithological investigations based on borehole data revealed that subsurface dams did not cause denitrification while the major NE-SW fault system uplifted the impermeable basement rock of the Shimajiri Group, creating a lithological gap at an equivalent depth that ultimately formed a sluggish groundwater area, promoting denitrification.

Metagenomic analysis of the microbial communities and associated network of nitrogen metabolism genes in the Ryukyu limestone aquifer.

While microbial biogeochemical activities such as those involving denitrification and sulfate reduction have been considered to play important roles in material cycling in various aquatic ecosystems, our current understanding of the microbial community in groundwater ecosystems is remarkably insufficient. To assess the groundwater in the Ryukyu limestone aquifer of Okinawa Island, which is located in the southernmost region of Japan, we performed metagenomic analysis on the microbial communities at the three sites and screened for functional genes associated with nitrogen metabolism. 16S rRNA amplicon analysis showed that bacteria accounted for 94-98% of the microbial communities, which included archaea at all three sites. The bacterial communities associated with nitrogen metabolism shifted by month at each site, indicating that this metabolism was accomplished by the bacterial community as a whole. Interestingly, site 3 contained much higher levels of the denitrification genes such as narG and napA than the other two sites. This site was thought to have undergone denitrification that was driven by high quantities of dissolved organic carbon (DOC). In contrast, site 2 was characterized by a high nitrate-nitrogen (NO3-N) content and a low amount of DOC, and this site yielded a moderate amount of denitrification genes. Site 1 showed markedly low amounts of all nitrogen metabolism genes. Overall, nitrogen metabolism in the Ryukyu limestone aquifer was found to change based on environmental factors.

Clinical Outcomes of Condoliase Injection Therapy for Lateral Lumbar Disc Herniation.

Introduction: This study aimed to evaluate the efficacy of condoliase injection therapy (CIT) for lateral lumbar disc herniation (LLDH). Methods: This retrospective study included 157 of 180 enrolled patients (70 males, 87 females; mean age: 52.6±16.9 years). These patients were divided into two groups (group L: LLDH, group M: medial LDH [subligamentous and transligamentous]). From baseline to 1 year after injection (final follow-up), leg pain was assessed using the visual analog scale (VAS) and the Japanese Orthopedic Association (JOA) scoring for CIT's clinical efficacy of CIT. Radiography and magnetic resonance imaging conducted before and 3 months after the injection were assessed. Patients with a VAS improvement of ≥50% at the final follow-up were defined as responders. The responder and nonresponder LLDH groups were also compared. Results: Groups L and M showed comparable responder rates (75.0% and 77.4%, respectively) (P=0.80). VAS and JOA scores at 1 year showed no significant differences between the groups (P=0.82 and 0.80, respectively). VAS score at 1 month after injection reduced considerably in the responder group compared with that in the nonresponder group (19.7 vs. 66.0, P<0.01) and continued to decrease at the last follow-up (3.5 vs. 52.0, P<0.001). Nonresponders had significantly lower disc heights after 3 months. However, intervertebral instability, alignment, and disc degeneration did not differ between the responders and nonresponders. Conclusions: The response rate of CIT for LLDH was comparable to that for medial LDH. Therefore, CIT is an effective treatment for LLDH.