Kyotaro Ota

Resection of Beak-Type Thoracic Ossification of the Posterior Longitudinal Ligament from a Posterior Approach under Intraoperative Neurophysiological Monitoring for Paralysis after Posterior Decompression and Fusion Surgery

Study Design Prospective clinical study. Objective Posterior decompression and fusion surgery for beak-type thoracic ossification of the posterior longitudinal ligament (T-OPLL) generally has a favorable outcome. However, some patients require additional surgery for postoperative severe paralysis, a condition that is inadequately discussed in the literature. The objective of this study was to describe the efficacy of a procedure we refer to as “resection at an anterior site of the spinal cord from a posterior approach” (RASPA) for severely paralyzed patients after posterior decompression and fusion surgery for beak-type T-OPLL. Methods Among 58 consecutive patients who underwent posterior decompression and fusion surgery for beak-type T-OPLL since 1999, 3 with postoperative paralysis (5%) underwent RASPA in our institute. Clinical records, the Japanese Orthopaedic Association score, gait status, intraoperative neurophysiological monitoring (IONM) findings, and complications were evaluated in these cases. Results All three patients experienced a postoperative decline in Manual Muscle Test (MMT) scores of 0 to 2 after the first surgery. RASPA was performed 3 weeks after the first surgery. All patients showed gradual improvements in MMT scores for the lower extremity and in ambulatory status; all could walk with a cane at an average of 4 months following RASPA surgery. There were no postoperative complications. Conclusions RASPA surgery for beak-type T-OPLL after posterior decompression and fusion surgery resulted in good functional outcomes as a salvage surgery for patients with severe paralysis. Advantages of RASPA include a wide working space, no spinal cord retraction, and additional decompression at levels without T-OPLL resection and spinal cord shortening after additional dekyphosis and compression maneuvers. When used with IONM, this procedure may help avoid permanent postoperative paralysis.

Optimal Timing of Surgery for Intramedullary Cavernous Hemangioma of the Spinal Cord in Relation to Preoperative Motor Paresis, Disease Duration, and Tumor Volume and Location

Study Design: Prospective study. Objective: Investigate factors associated with preoperative motor paresis, recovery, ambulatory status, and intraoperative neurophysiological monitoring (IONM) among patients with no preoperative paresis (N group), complete preoperative motor recovery (CR group), and no complete recovery (NCR group) in patients with intramedullary spinal cavernous hemangioma to determine the optimal timing of surgery. Methods: The study evaluated 41 surgical cases in our institute. Disease duration, tumor lesion, manual muscle testing (MMT), and gait at onset, just before surgery, and final follow-up (FU), tumor and lesion volume, IONM, extent of tumor resection, and tumor recurrence were evaluated among N, CR, and NCR groups. Results: Motor paresis at onset was found in 26 patients (63%), with 42% of those in CR group. Disease duration from onset negatively affected stable gait just before surgery and FU as well as lower preoperative MMT (P < .05). Thoracic tumors were associated with patients with unstable gait before surgery (P < .05). Tumor volume was larger in NCR group (P < .05). IONM significantly decreased in NCR and CR groups than in N group (P < .05). The NCR group had residual mild motor paresis at FU (P < .05). Stable gait at FU was similar in N group and CR group, though lower in NCR group (P < .05). Conclusions: Early surgery is generally recommended for thoracic tumors and large tumors during stable gait without motor paresis before long disease duration. Surgery may be postponed until patients recover from preoperative motor paresis to allow optimal surgical outcome. IONM should be carefully monitored in patients with a history of preoperative paresis even with preoperative complete motor recovery.

A low phase angle measured with bioelectrical impedance analysis is associated with osteoporosis and is a risk factor for osteoporosis in community-dwelling people: the Yakumo study

SummaryAlthough the phase angle has been reported to be related to predictive factors and therapeutic effects in various diseases, its relation with osteoporosis is unclear. In our large prospective survey of community-dwelling people, a low phase angle was related with osteoporosis, and it could be a predictor of osteoporosis.PurposeThe phase angle measured with bioelectrical impedance analysis (BIA) is one of the clinically important impedance parameters, and it is a predictor of prognosis and mortality for several diseases. The present cross-sectional study aimed to elucidate the association between osteoporosis and variables measured with BIA, including the phase angle.MethodsThe study included 307 participants from an annual health checkup. All participants underwent measurement of bone status by quantitative ultrasound and body composition by BIA. Osteoporosis was diagnosed according to the WHO classification, and statistical comparisons were conducted between normal individuals and osteoporosis patients.ResultsAge, proteins, minerals, and the phase angle were significantly different between normal individuals and osteoporosis patients (p < 0.001). Furthermore, after controlling for age and sex, proteins, minerals, and the phase angle were significantly lower in osteoporosis patients than those in normal individuals (p < 0.001). In multivariate logistic regression analysis, older age and a low phase angle were risk factors for osteoporosis. Additionally, multiple regression analysis showed that age, sex, proteins, minerals, and the appendicular skeletal muscle index were significantly related to the phase angle.ConclusionsThe phase angle is a predictor of osteoporosis, which is unaffected by age and sex, and a lower phase angle is associated with greater probability of osteoporosis. The phase angle can be easily measured, and osteoporosis can be confirmed even at home. This may facilitate early diagnosis and treatment, which may be useful for preventing diseases related to osteoporosis.

Risk Factors for Ineffectiveness of Posterior Decompression and Dekyphotic Corrective Fusion with Instrumentation for Beak-Type Thoracic Ossification of the Posterior Longitudinal Ligament: A Single Institute Study.

BACKGROUND: Thoracic ossification of the posterior longitudinal ligament (T‐OPLL) is treated surgically with instrumented posterior decompression and fusion. However, the factors determining the outcome of this approach and the efficacy of additional resection of T‐OPLL are unknown. OBJECTIVE: To identify these factors in a prospective study at a single institution. METHODS: The subjects were 70 consecutive patients with beak‐type T‐OPLL who underwent posterior decompression and dekyphotic fusion and had an average of 4.8 years of follow‐up (minimum of 2 years). Of these patients, 4 (6%; group R) had no improvement or aggravation, were not ambulatory for 3 weeks postoperatively, and required additional T‐OPLL resection; while 66 (group N) required no further T‐OPLL resection. Clinical records, gait status, intraoperative ultrasonography, intraoperative neurophysiological monitoring (IONM), plain radiography, computed tomography and magnetic resonance imaging findings, and Japanese Orthopaedic Association (JOA) score were compared between the groups. RESULTS: Preoperatively, patients in group R had significantly higher rates of severe motor paralysis, nonambulatory status, positive prone and supine position test, no spinal cord floating in intraoperative ultrasonography, and deterioration of IONM at the end of surgery (P < .05). In preoperative radiography, the OPLL spinal cord kyphotic angle difference in fused area, OPLL length, and OPLL canal stenosis were significantly higher in group R (P < .05). At final follow‐up, JOA scores improved similarly in both groups. CONCLUSION: Preoperative severe motor paralysis, nonambulatory status, positive prone and supine position test, radiographic spinal cord compression due to beak‐type T‐OPLL, and intraoperative residual spinal cord compression and deterioration of IONM were associated with ineffectiveness of posterior decompression and fusion with instrumentation. Our 2‐stage strategy may be appropriate for beak‐type T‐OPLL surgery.

Effects of a self-assembling peptide as a scaffold on bone formation in a defect

Spinal fusion and bone defect after injuries, removal of bone tumors, and infections need to be repaired by implantation. In an aging society, recovery from these procedures is often difficult. In this study, we found that injection of SPG-178 leads to expression of several bone marker genes and mineralization in vitro, and revealed a significantly higher degree of newly formed bone matrix with use of SPG-178 in vivo. MC3T3-E1 cells were used to evaluate osteoblast differentiation promoted by SPG-178. To analyze gene expression, total RNA was isolated from MC3T3-E1 cells cultured for 7 and 14 days with control medium or SPG-178 medium. Among the several bone marker genes examined, SPG-178 significantly increased the mRNA levels for ALP, BMP-2 and Osteocalcin, OPN, BSP and for the Osterix. Ten-week-old female Wistar rats were used for all transplantation procedures. A PEEK cage was implanted into a bony defect (5 mm) within the left femoral mid-shaft, and stability was maintained by an external fixator. The PEEK cages were filled with either a SPG-178 hydrogel plus allogeneic bone chips (n = 4) or only allogeneic bone chips (n = 4). The rats were then kept for 56 days. Newly formed bone matrix was revealed inside the PEEK cage and there was an increased bone volume per total volume with the cage filled with SPG-178, compared to the control group. SPG-178 has potential in clinical applications because it has several benefits. These include its favorable bone conduction properties its ability to act as a support for various different cells and growth factors, its lack of infection risk compared with materials of animal origin such as ECM, and the ease with which it can be used to fill defects with complex shapes and combined with a wide range of other materials.

Accuracy of intraoperative pathological diagnosis using frozen sections of spinal cord lesions

OBJECTIVES Frozen sections are used to provide gross and rapid microscopic pathological information for guidance on intraoperative management and therapeutic decision-making. Many studies have shown the accuracy of frozen section diagnosis for intracranial lesions, but there are no studies focusing on spinal cord lesions. The purpose of this study is to evaluate the accuracy of intraoperative rapid diagnosis using frozen sections and to investigate limitations of this approach for spinal cord lesions. PATIENTS AND METHODS We performed intraoperative pathological diagnosis using frozen sections in 67 cases in which it was difficult to determine malignancy in preoperative images. The lesions were extradural (ED) in 13 cases, intradural extramedullary (IDEM) in 27 cases, and intramedullary (IM) in 27 cases. Metastatic tumors were excluded. The accuracy of intraoperative pathological diagnosis and the patterns of incorrect diagnosis were examined. RESULTS Comparison of the intraoperative and final diagnoses gave an overall diagnostic sensitivity of 86.6% (58/67), with 100% (13/13) for ED lesions, 96% (26/27) for IDEM lesions, and 70% (19/27) for IM lesions. The diagnostic accuracy for IM lesions was significantly lower than those for ED and IDEM lesions (p < 0.05). Cases with small specimen sizes were frequently incorrectly diagnosed and inflammatory processes were common incorrect diagnoses using frozen specimens. CONCLUSION Among all spinal cord lesions, low diagnostic accuracy in intraoperative diagnosis using frozen sections is most likely for intramedullary lesions. The results of intraoperative rapid diagnosis should be interpreted with understanding of the limitations of this procedure.

Perioperative Management of Patients with Hemophilia during Spinal Surgery

Study Design Single-center retrospective study. Purpose To optimize the perioperative management of patients with hemophilia who are undergoing spinal surgery. Overview of Literature Hemophilia is a rare disease in which there is a tendency of bleeding because of a congenital deficiency in blood coagulation factor activity. There has been no previous report on spinal surgery in patients with hemophilia. Methods The subjects were five patients (all males) with hemophilia who underwent spinal surgery at Nagoya University Hospital. Two patients had hemophilia A (deficiency of factor VIII) and three had hemophilia B (deficiency of factor IX). The mean age at the time of surgery was 63 years (range, 46–73 years). The following surgeries were performed: posterior lumbar interbody fusion (PLIF) in two patients, and lumbar fenestration, cervical laminoplasty and lumbar fenestration, and cervical laminoplasty and PLIF in one patient each. Results Coagulation factor at a mean dose of 4.8 ×103 U (range, 3–6 ×103 U) was intravenously injected before surgery, and a mean dose of 5.2 ×103 U (rang, 4–6 ×103 U) was continuously administered for 24 hours after surgery. Factor activity was maintained at ≥80% until postoperative day 14 and at ≥50% thereafter. The average duration of surgery was 178 minutes (range, 133–233 minutes), the estimated blood loss was 661 mL (range, 272–1,344 mL), and a drain tube was left subfascially in place for 2 days in all patients. Reoperation due to postoperative surgical site infection was required in one patient, but there were no complications due to hemorrhagic diathesis. The total dose of coagulation factor administered during hospitalization was 102 ×103 U (range, 46–198 ×103 U). Conclusions Coordination with a hematologist and dose adjustment of the coagulation factor preparation to maintain a target level of coagulation factor activity facilitated a smooth postoperative course with perioperative control of bleeding during spinal surgery for patients with hemophilia.

Factors for a Good Surgical Outcome in Posterior Decompression and Dekyphotic Corrective Fusion with Instrumentation for Thoracic Ossification of the Posterior Longitudinal Ligament: Prospective Single-Center Study

BACKGROUND Surgery for thoracic ossification of the posterior longitudinal ligament (T-OPLL) is still challenging, and factors for good surgical outcomes are unknown. OBJECTIVE To identify factors for good surgical outcomes with prospective and comparative study. METHODS Seventy-one consecutive patients who underwent posterior decompression and instrumented fusion were divided into good or poor outcome groups based on ≥50% and <50% recovery rates for the Japanese Orthopaedic Association score. Preoperative, intraoperative, and postoperative findings were compared in the 2 groups, and significant factors for a good outcome were analyzed. RESULTS Patients with a good outcome (76%) had significantly lower nonambulatory rate and positive prone and supine position tests preoperatively; lower rates of T-OPLL, ossification of the ligamentum flavum, high-intensity area at the same level, thoracic spinal cord alignment difference, and spinal canal stenosis on preoperative magnetic resonance imaging; lower estimated blood loss; higher rates of intraoperative spinal cord floating and absence of deterioration of intraoperative neurophysiological monitoring; and lower rates of postoperative complications (P < .0005). In multivariate logistic regression analysis, negative prone and supine position test (odds ratio [OR]: 17.00), preoperative ambulatory status (OR: 6.05), absence of T-OPLL, ossification of the ligamentum flavum, high-intensity area at the same level (OR: 5.84), intraoperative spinal cord floating (OR: 4.98), and lower estimated blood loss (OR: 1.01) were significant factors for a good surgical outcome. CONCLUSION This study demonstrated that early surgery is recommended during these positive factors. Appropriate surgical planning based on preoperative thoracic spinal cord alignment difference, as well as sufficient spinal cord decompression and reduction of complications using intraoperative ultrasonography and intraoperative neurophysiological monitoring, may improve surgical outcomes.

Lack of Fgf18 causes abnormal clustering of motor nerve terminals at the neuromuscular junction with reduced acetylcholine receptor clusters

FGF receptor 2 is involved in the formation of the neuromuscular junction (NMJ), but its in vivo ligand remains to be determined. Laser capture microdissection of the mouse spinal motor neurons (SMNs) revealed that Fgf18 mRNA is highly expressed in SMNs in adults. Expression of Fgf18 mRNA was the highest in the spinal cord at embryonic day (E) 15.5, which gradually decreased to postnatal day 7. FGF18 protein was localized at the NMJs of the tibialis anterior muscle at E18.5 and in adults. Fgf18−/− mice at E18.5 showed decreased expressions of the NMJ-specific Chrne and Colq genes in the diaphragm. In Fgf18−/− diaphragms, the synaptophysin-positive areas at the nerve terminals and the acetylcholine receptor (AChR)-positive areas at the motor endplates were both approximately one-third of those in wild-type embryos. Fgf18−/− diaphragms ultrastructurally showed abnormal aggregation of multiple nerve terminals making a gigantic presynapse with sparse synaptic vesicles, and simplified motor endplates. In Fgf18−/− diaphragms, miniature endplate potentials were low in amplitude with markedly reduced frequency. In C2C12 myotubes, FGF18 enhanced AChR clustering, which was blocked by inhibiting FGFRs or MEK1. We propose that FGF18 plays a pivotal role in AChR clustering and NMJ formation in mouse embryogenesis.

Wave Change of Intraoperative Transcranial Motor-Evoked Potentials During Corrective Fusion for Syndromic and Neuromuscular Scoliosis

BACKGROUND There is little information on intraoperative neuromonitoring during correction fusion surgery for syndromic scoliosis. OBJECTIVE To investigate intraoperative TcMEPs and conditions (body temperature and blood pressure) for syndromic scoliosis. METHODS The subjects were 23 patients who underwent 25 surgeries for corrective fusion using TcMEP. Patients were divided into groups based on a decrease (DA+) or no decrease (DA-) of the amplitude of the TcMEP waveform of ≥70%. The groups were compared for age, sex, disease, type of surgery, fusion area, operation time, estimated blood loss, body temperature, blood pressure, Cobb angle, angular curve (Cobb angle/number of vertebra), bending flexibility, correction rate, and recovery. RESULTS The mean Cobb angles before and after surgery were 85.2° and 29.1°, giving a correction rate of 68.2%. There were 16 surgeries (64.0%) with intraoperative TcMEP wave changes. The DA+ and DA- groups had similar intraoperative conditions, but the short angular curve differed significantly between these groups. Amplitude deterioration occurred in 4 cases during first rod placement, in 8 during rotation, and in 3 during second rod placement after rotation. Seven patients had complete loss of TcMEP. However, most TcMEP changes recovered after pediclectomy or decreased correction. The preoperative angular curve differed significantly between patients with and without TcMEP changes (P < .05). CONCLUSION Intraoperative TcMEP wave changes occurred in 64.0% of surgeries for corrective fusion, and all but one of these changes occurred during the correction procedure. The angular curve was a risk factor for intraoperative motor deficit.