Microendoscopy-assisted extraforaminal lumbar interbody fusion for treating single-level spondylodesis.

BACKGROUND: Lumbar interbody fusion is a standard technique for treating degenerative lumbar disorders involving instability. Due to its invasiveness, a minimally invasive technique, extraforaminal lumbar interbody fusion (ELIF), was introduced. On surgically approaching posterolaterally, the posterior muscles and spinal canal are barely invaded. Despite its theoretical advantage, ELIF is technically demanding and has not been popularised. Therefore, we developed a microendoscopy-assisted ELIF (mELIF) technique which was designed to be safe and less invasive. Here, we aimed to report on the surgical technique and clinical results. METHODS: Using a posterolateral approach similar to that of lateral disc herniation surgery, a tubular retractor, 16 or 18 mm in diameter, was placed at the lateral aspect of the facet joint. The facet joint was partially excised, and the disc space was cleaned. A cage and local bone graft were inserted into the disc space. All disc-related procedures were performed under microendoscopy. The spinal canal was not invaded. Bilateral percutaneous screw-rod constructs were inserted and fixed. RESULTS: Fifty-five patients underwent the procedure. The Oswestry Disability Index and visual analogue scale scores greatly improved. Over 90% of the patients obtained excellent or good results based on Macnab's criteria. There were neither major adverse clinical effects nor the need for additional surgery. CONCLUSIONS: mELIF is minimally invasive because the spinal canal and posterior muscles are barely invaded. It produces good clinical results with fewer complications. This technique can be applied in most single-level spondylodesis cases, including those involving L5/S1 disorders.

Clinical Comparison of Unilateral Biportal Endoscopic Laminectomy versus Microendoscopic Laminectomy for Single-Level Laminectomy: A Single-Center, Retrospective Analysis.

BACKGROUND: The purpose of this study was to compare clinical results of microendoscopic laminectomy (MEL) with those of unilateral biportal endoscopic laminectomy (UBEL) in patients with single-level lumbar spinal canal stenosis. METHODS: The subjects consisted of 181 patients who underwent MEL (139 cases) and UBEL (42 cases) who were followed up for at least 6 months. All patients had lumber canal stenosis for 1 level. Outcomes of the patients were assessed with the duration of surgery, the bone resection area in 3-dimensional computed tomography, the facet preservation rates in computed tomography axial imagery, Visual Analog Scale (VAS) for low back pain, the Oswestry Disability Index, and the EuroQol 5-Dimensions questionnaire. RESULTS: The bone resection area in 3-dimensional computed tomography was 1.5 for MEL versus 1.0 cm2 for UBEL (P < 0.05). The facet preservation rates on the advancing side and the opposite side were 78% versus 86% (advancing side: MEL vs. UBEL) and 85% versus 94% (opposite side) (P < 0.05). The VAS (low back pain) score, VAS (leg pain), Oswestry Disability Index, and EuroQol 5-Dimension questionnaire significantly dropped in both groups at the final period (P < 0.05), however, exhibiting no difference between the 2 groups at each period. MEL resulted in greater numbers of complications, including 5 cases of hematoma paralysis, 8 cases of dura injury, 2 cases of reoperation, as opposed to zero cases of hematoma paralysis and only 2 cases of dura injury resulting from UBEL. CONCLUSIONS: The UBEL method is a more useful technique than the MEL method as it requires a smaller bone resection area and produces fewer complications.

Postoperative Outcomes After Transsacral Epiduroscopic Laser Decompression in Japanese Patients: Denervation Therapy for Discogenic Low-Back Pain.

Background: Transsacral epiduroscopic laser decompression (SELD) is a very noninvasive surgery, so it is effective for elderly patients and athletes and is a new and minimally invasive therapeutic technique that may be useful in many patients with discogenic low-back pain (LBP) having high signal intensity zone (HIZ) in magnetic resonance imaging (MRI). We investigated the clinical outcomes of SELD in Japanese patients with discogenic LBP having HIZ as a first trial. Methods: The subjects consisted of 52 patients who underwent SELD and were followed up for at least 6 months. All patients with LBP with HIZ were operative using the SELD technique. Outcomes of the patients were assessed with visual analogue scale (VAS) for LBP, the Oswestry disability index (ODI), and the EuroQol 5 dimension (EQ-5D). Statistical analyses were carried out using a paired t-test. A p-value of <0.05 was considered significant. For statistical analysis, we used the SPSS software program. Results: At 12 months after the procedure, the average VAS score for LBP fell to 1.2 from 5.6 (p-value <0.05). The ODI score also dropped from the preoperative level of 22.3 to 8.8. The EQ-5D score also significantly increased from the preoperative level of 0.865 (SD 0.10) to 0.950 (SD 0.05). Eight cases of intraoperative cervical pain were observed as complications with no cases of hematomas, infections, and postoperative neurosis was observed. Conclusions: SELD provides a novel minimally invasive technique capable of performing multilevel intervertebral surgery. We believe that SELD is an effective method of treating discogenic LBP due to HIZs.

Methods and Early Clinical Results of Percutaneous Lumbar Interbody Fusion.

OBJECTIVE: Percutaneous lumbar interbody fusion (PELIF) is a procedure that includes the use of new devices, which allow minimally invasive diskectomy under the percutaneous full-endoscopic guidance and safe percutaneous insertion of a standard-sized cage. This procedure can be applied to severe disk degeneration, spondylolisthesis, and all lumbar intervertebral levels including the L5-S1 level. We report the methods and the clinical outcomes of this procedure. METHODS: Percutaneous diskectomy was performed with an outer sheath cutter and other devices. A cage was inserted with an L-shaped retract-slider. Hybrid facet screw fixation was performed for severe disk degeneration without spondylolisthesis. Conventional percutaneous pedicle screw fixation was performed for spondylolisthesis. The subjects consisted of 21 patients, who underwent PELIF and were followed up for 1 year or longer. RESULTS: No complications related to cage insertion were detected. The mean visual analogue scale scores were improved from 6.1 to 1.9 for lower back pain in severe disc degeneration cases without spondylolisthesis, and from 7.6 to 1.0 for lower extremity symptoms in spondylolisthesis cases. CONCLUSION: The clinical outcomes were favorable. PELIF was found to be a minimally invasive method that did not compromise safety and efficiency. PELIF is a possible therapeutic option that should be considered for not only spondylolisthesis at various intervertebral levels but also for severe disk degeneration because of its minimal invasiveness.

Step-by-Step Sublaminar Approach With a Newly-Designed Spinal Endoscope for Unilateral-Approach Bilateral Decompression in Spinal Stenosis.

OBJECTIVE: Spinal stenosis is increasingly common due to population aging. In elderly patients with lumbar central canal stenosis (LCCS), minimizing muscle damage and bone resection is particularly important. We performed a step-by-step operation with a newly designed spinal endoscope to obtain adequate decompression in patients with spinal stenosis. METHODS: From April 2015 to August 2016, 78 patients (48 males, 30 females) with LCCS (91 segments) underwent endoscopic decompression using a newly designed endoscope system. The inclusion criteria were: (1) neurogenic intermittent claudication with or without radiculopathy, (2) LCCS, and (3) having exhausted conservative treatment (>3 months). The exclusion criteria were: (1) >10° of instability, (2) spondylolisthesis grade II or greater according to the Meyerding criteria, (3) foraminal stenosis, (4) vascular intermittent claudication, (5) infection, and (6) stenosis combined with malignancy. We performed a step-by-step procedure using a newly designed endoscope system for unilateral-approach bilateral decompression. We used the same incision for 2-3 segments, only moving the skin. RESULTS: The mean follow-up was 2.3±1.3 years. Excellent or good results were found according to the MacNab criteria in 85.9% of cases (67 of 78). The visual analogue scale, Japanese Orthopedic Association score, and Oswestry Disability Index showed significant decreases at 1 month, persisting until the 2-year follow-up. Dural tear occurred in 4 cases (5.1%), and patch repair was performed under endoscopy. No patients experienced aggravated instability requiring surgery. CONCLUSION: We obtained good results with endoscopic decompression surgery using a newly designed instrument that minimized muscle and bone damage in elderly patients with spinal stenosis.

Is a Drain Tip Culture Required After Spinal Surgery?

STUDY DESIGN: The efficacy of use of a drain tip culture for early detection of surgical-site infection (SSI) was investigated in 329 patients after spinal surgery. OBJECTIVE: To examine the efficacy of a wound drain tip culture for detection of SSI in spinal surgery. SUMMARY OF BACKGROUND DATA: A complication of SSI after spinal surgery has high associated morbidity and mortality, and is often difficult to treat. MATERIALS AND METHODS: The subjects were patients who underwent spinal surgery at our institution between January 2010 and March 2013. All subjects were treated with antimicrobial prophylaxis based on evidence-based guidelines and were followed for at least 6 months after surgery. Data from culture studies using the distal tip of the wound drain were used for analysis. RESULTS: Drain tip cultures were positive in 34 cases and there were 19 SSIs. Ten of the 34-tip culture-positive wounds developed SSI. Drain tip cultures had a sensitivity of 52%, specificity of 92%, positive predictive value (PPV) of 29%, and negative predictive value of 97% for predicting a wound infection. The association between a positive suction tip culture and wound infection was significant (P<0.05). The PPV for SSI was 60% in cases in which methicillin-resistant bacteria were detected in a drain tip, and the SSI rate in these cases differed significantly compared with those with non-methicillin-resistant bacteria (P=0.01). CONCLUSIONS: A drain tip culture is useful for early detection of SSI caused by methicillin-resistant bacteria.

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.

Minimum 5-year Follow-up Results for Occipitocervical Fusion Using the Screw-Rod System in Craniocervical Instability.

STUDY DESIGN: Retrospective clinical study. OBJECTIVE: To evaluate the clinical outcome of patients who had undergone occipitocervical (OC) fusion using pedicle screws and rods over a minimum 5-year follow-up. SUMMARY OF BACKGROUND DATA: Few studies have evaluated occipitocervical (OC) fusion using pedicle screws and rods for long-term follow-up. METHODS: Twenty-seven consecutive patients treated underwent posterior OC fusion using pedicle screws and rods over a minimum 5-year follow-up. The Modified McCormick scale to grade a patient's functional status and the Japanese Orthopaedic Association (JOA) scoring system were used to evaluate preoperative and postoperative neurological function. We assessed fusion by both direct and indirect evidence; bony trabeculae at the graft-recipient interface on lateral cervical radiographs and sagittal computed tomography reconstruction was considered direct evidence of union. RESULTS: The mean follow-up period was 7.2 years (5-14 y). JOA scores were 8.1±3.8 before surgery and 11.7±3.7 at the final follow-up. The recovery rate calculated from the JOA scores was 42.0±30.0%. Functional status did improve at least 1 grade according to the modified McCormick scale in 18 patients (66.7%). There was no deterioration at the final follow-up.There were postoperative implant-related complications in 8 patients (29.6%): loosening of pedicle screws in 2, rod breakage in 2, plate breakage in 1, screw breakage in 1, pullout of pedicle screws in 1, and wiring induced myelopathy in 1 patient. The average duration between surgery and implant failure was 31.2 months (12-60 mo) except for 2. CONCLUSIONS: Sufficient bone grafting, proper decortication of the bone bed, using thicker and high stiffness rods, and ultra-high molecular weight polyethylene tape as a fixation or reinforcement of implant may help prevent implant failure.

Ponte Osteotomy During Dekyphosis for Indirect Posterior Decompression With Ossification of the Posterior Longitudinal Ligament of the Thoracic Spine.

STUDY DESIGN: Retrospective clinical study. PURPOSE: To investigate the outcomes after indirect posterior decompression and dekyphosis using multilevel Ponte osteotomies for ossification of the posterior longitudinal ligament (OPLL) of the thoracic spine. SUMMARY OF BACKGROUND DATA: There are no previous reports on the use of Ponte osteotomy to treat thoracic OPLL. METHODS: The subjects were 10 patients with an average age at surgery of 47 years, who underwent indirect posterior decompression and dekyphosis using multilevel Ponte osteotomies at our institute. Minimum follow-up period was 2 years, and averaged 2 year 6 months. Using radiographs and CT images, we investigated fusion range, preoperative and postoperative Cobb angles of thoracic fusion levels, intraoperative ultrasonography, and clinical results. RESULTS: The mean fusion area was 9.8 vertebraes, with average laminectomy of 7.3 laminas. The mean preoperative thoracic kyphosis of fusion levels on standing radiograph measured 35 degrees and was changed to 21 degrees after surgery. The mean number of Ponte osteotomies was 3 levels. The mean preoperative and postoperative (at the 1 y follow-up) JOA scores were 3.5 and 7.5 points, respectively, and the recovery rate was 56%. On intraoperative ultrasonography, 7 of the cases were included in the floating (+) and 3 in the floating (-) groups, and the recovery rates were 66.0% and 33.4%, respectively. CONCLUSIONS: "The Ponte procedure for indirect spinal cord decompression" is a novel concept used for the first time with thoracic OPLL in our study, and we consider it a useful method to achieve more effectively dekyphosis and indirect spinal cord decompression if there is not the spinal cord free from OPLL on intraoperative ultrasonography after only laminectomies.

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.

Rapid Worsening of Symptoms and High Cell Proliferative Activity in Intra- and Extramedullary Spinal Hemangioblastoma: A Need for Earlier Surgery.

STUDY DESIGN: A retrospective analysis of a prospective database. OBJECTIVE: To compare preoperative symptoms, ambulatory ability, intraoperative spinal cord monitoring, and pathologic cell proliferation activity between intramedullary only and intramedullary plus extramedullary hemangioblastomas, with the goal of determining the optimal timing for surgery. METHODS: The subjects were 28 patients (intramedullary only in 23 cases [group I] and intramedullary plus extramedullary in 5 cases [group IE]) who underwent surgery for spinal hemangioblastoma. Preoperative symptoms, ambulatory ability on the McCormick scale, intraoperative spinal cord monitoring, and pathologic findings using Ki67 were compared between the groups. RESULTS: In group IE, preoperative motor paralysis was significantly higher (100 versus 26%, p < 0.005), the mean period from initial symptoms to motor paralysis was significantly shorter (3.5 versus 11.9 months, p < 0.05), and intraoperative spinal cord monitoring aggravation was higher (65 versus 6%, p < 0.05). All 5 patients without total resection in group I underwent reoperation. Ki67 activity was higher in group IE (15% versus 1%, p < 0.05). Preoperative ambulatory ability was significantly poorer in group IE (p < 0.05), but all cases in this group improved after surgery, and postoperative ambulatory ability did not differ significantly between the two groups. CONCLUSIONS: Intramedullary plus extramedullary spinal hemangioblastoma is characterized by rapid preoperative progression of symptoms over a short period, severe spinal cord damage including preoperative motor paralysis, and poor gait ability compared with an intramedullary tumor only. Earlier surgery with intraoperative spinal cord monitoring is recommended for total resection and good surgical outcome especially for an IE tumor compared with an intramedullary tumor.

Prevention of spinal cord injury using brain-evoked muscle-action potential (Br(E)-MsEP) monitoring in cervical spinal screw fixation.

PURPOSE: The goal of the study was to examine waveform deterioration in intraoperative monitoring during posterior fusion with a cervical screw. This surgery is useful for alignment correction, but worsening of neurological symptoms may occur in association with screw insertion and rod installation. Therefore, spinal cord monitoring is important for safe surgery. METHODS: The study included 25 cases treated with posterior fusion with a cervical screw. Waveform deterioration was defined as an intraoperative amplitude <50% of the control waveform. Comparisons were made between cases with normal and deteriorated waveforms. RESULTS: Intraoperative waveform deterioration occurred in nine cases, including after screw insertion in 8 and after rod installation in one. The nine patients with deteriorated waveforms had a significantly lower preoperative JOA score (8.8 vs. 11.2, P < 0.05) and a tendency for more frequent high signal intensity on MRI [67% (6/9) vs. 31% (5/16), P = 0.087]. Cases in which stenosis was greatest at the apex of the cervical lordosis had significantly more frequent intraoperative waveform deterioration [46% (6/13) vs. 0% (0/8), P < 0.05]. In cases in which the narrowest segment was at the apex of the cervical lordosis, screw insertion before compared to after decompression significantly increased waveform deterioration [67% (6/9) vs. 0% (0/4), P < 0.05]. CONCLUSION: Intraoperative waveform deterioration in posterior cervical screw fixation is associated with severe preoperative symptoms, location of the narrowest segment, and screw insertion before decompression. It is particularly desirable to perform decompression before screw insertion in cases with the narrowest segment at the apex of the cervical lordosis.

Screw fixation for atlantoaxial dislocation related to Down syndrome in children younger than 5 years.

The aim of this study was to present cases of upper cervical fixation in Down syndrome patients younger than 5 years. In two cases, C1 lateral mass screws were installed. However, owing to the irreducible atlantoaxial dislocation, the screw backed out and fractured. Therefore, O-C2 fusion was performed. Furthermore, C2 bilateral lamina screws were added to the C2 pedicle screw for reinforcement. C1-C2 fusion is an option for Down syndrome patients younger than 5 years with atlantoaxial dislocation, when the dislocation is reducible. If the dislocation is irreducible, or the implant cannot be firmly secured, the fixation range should be expanded to O-C2 or below.

MRI Signal Intensity Classification in Cervical Ossification of the Posterior Longitudinal Ligament: Predictor of Surgical Outcomes.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: To investigate whether classification of increased signal intensity (ISI) on magnetic resonance imaging (MRI) of spinal cord in patients with cervical ossification of the posterior longitudinal ligament (C-OPLL) reflects severity of myelopathy and surgical outcome. SUMMARY OF BACKGROUND DATA: The relationship between classification of ISI on C-OPLL and severity is unknown. METHODS: The 119 consecutive patients (91 men, 28 women) with C-OPLL who underwent surgery were enrolled. T2-weighted MRI was performed before surgery and ISI was classified into three groups as follows, Grade 0, none; Grade 1, light (obscure); and Grade 2, intense (bright). The severity of myelopathy and surgical outcome were evaluated by the Japanese Orthopedic Association score. To determine factors that influence ISI, the change of the spinal cord cross-sectional area (SCA) during flexion and extension was calculated by computed tomography after myelography. RESULTS: The preoperative MRI showed 55 patients in Grade 0, 46 patients in Grade 1, and 18 patients in Grade 2. The preoperative Japanese Orthopedic Association score (Grade 0, 11.2; Grade 1, 10.3; Grade 2, 9.6 points) and surgical outcome got worsened with increasing ISI grade. The patients in Grade 2 had a longer duration of disease, while those in Grade 1 and Grade 2 had a larger change of SCA during flexion and extension (Grade 0, 4.8 mm; Grade 1, 7.3 mm; Grade 2, 7.8 mm). However age, alignment of the cervical spine, range of motion, and occupying ratio of the ossification were not different in the three grades. CONCLUSION: Grade of ISI correlated with preoperative severity of myelopathy and surgical outcome in patients with C-OPLL. Increased signal intensity of the spinal cord on MRI was associated with a larger change in SCA and longer duration of disease. LEVEL OF EVIDENCE: 3.

Transcranial motor evoked potential waveform changes in corrective fusion for adolescent idiopathic scoliosis.

OBJECTIVE Corrective surgery for spinal deformities can lead to neurological complications. Several reports have described spinal cord monitoring in surgery for spinal deformity, but only a few have included patients younger than 20 years with adolescent idiopathic scoliosis (AIS). The goal of this study was to evaluate the characteristics of cases with intraoperative transcranial motor evoked potential (Tc-MEP) waveform deterioration during posterior corrective fusion for AIS. METHODS A prospective database was reviewed, comprising 68 patients with AIS who were treated with posterior corrective fusion in a prospective database. A total of 864 muscles in the lower extremities were chosen for monitoring, and acceptable baseline responses were obtained from 819 muscles (95%). Intraoperative Tc-MEP waveform deterioration was defined as a decrease in intraoperative amplitude of ≥ 70% of the control waveform. Age, Cobb angle, flexibility, operative time, estimated blood loss (EBL), intraoperative body temperature, blood pressure, number of levels fused, and correction rate were examined in patients with and without waveform deterioration. RESULTS The patients (3 males and 65 females) had an average age of 14.4 years (range 11-19 years). The mean Cobb angles before and after surgery were 52.9° and 11.9°, respectively, giving a correction rate of 77.4%. Fourteen patients (20%) exhibited an intraoperative waveform change, and these occurred during incision (14%), after screw fixation (7%), during the rotation maneuver (64%), during placement of the second rod after the rotation maneuver (7%), and after intervertebral compression (7%). Most waveform changes recovered after decreased correction or rest. No patient had a motor deficit postoperatively. In multivariate analysis, EBL (OR 1.001, p = 0.085) and number of levels fused (OR 1.535, p = 0.045) were associated with waveform deterioration. CONCLUSIONS Waveform deterioration commonly occurred during rotation maneuvers and more frequently in patients with a larger preoperative Cobb angle. The significant relationships of EBL and number of levels fused with waveform deterioration suggest that these surgical invasions may be involved in waveform deterioration.

Prevalence and distribution of ossification of the supra/interspinous ligaments in symptomatic patients with cervical ossification of the posterior longitudinal ligament of the spine: a CT-based multicenter cross-sectional study.

BACKGROUND: Supra/interspinous ligaments connect adjacent spinous processes and act as a stabilizer of the spine. As with other spinal ligaments, it can become ossified. However, few report have discussed ossification supra/interspinous ligaments (OSIL), so its epidemiology remains unknown. We therefore aimed to investigate the prevalence and distribution of OSIL in symptomatic patients with cervical ossification of the posterior longitudinal ligament (OPLL). METHODS: The participants of our study were symptomatic patients with cervical OPLL who were diagnosed by standard radiographs of the cervical spine. The whole spine CT data as well as clinical parameters such as age and sex were obtained from 20 institutions belong to the Japanese Multicenter Research Organization for Ossification of the Spinal Ligament (JOSL). The prevalence and distribution of OSIL and the association between OSIL and clinical parameters were reviewed. The sum of the levels involved by OPLL (OP-index) and OSIL (OSI-index) as well as the prevalence of ossification of the nuchal ligament (ONL) were also investigated. RESULTS: A total of 234 patients with a mean age of 65 years was recruited. The CT-based evidence of OSIL was noted in 68 (54 males and 14 females) patients (29%). The distribution of OSIL showed a significant thoracic preponderance. In OSIL-positive patients, single-level involvement was noted in 19 cases (28%), whereas 49 cases (72%) presented multi-level involvement. We found a significant positive correlation between the OP-index grade and OSI-index. ONL was noted at a significantly higher rate in OSIL-positive patients compared to negative patients. CONCLUSIONS: The prevalence of OSIL in symptomatic patients with cervical OPLL was 29%. The distribution of OSIL showed a significant thoracic preponderance.

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.

Self-assembling Peptide Reduces Glial Scarring, Attenuates Posttraumatic Inflammation, and Promotes Neurite Outgrowth of Spinal Motor Neurons.

STUDY DESIGN: Self-assembling peptide gel (SPG-178) provides new evidence for the role of a scaffold for treatment of the spinal cord through induction of neuroprotective factors. OBJECTIVE: To verify the reproducibility of SPG-178 as scaffold after spinal cord injury, we examine the characteristics of SPG-178 and protective effect on neural cells in vitro and in vivo. SUMMARY OF BACKGROUND DATA: The central nervous system extracellular matrix may play a role in maintenance of the neuronal network by inhibiting axonal growth and suppressing formation of additional inadequate synapses. In this study, we show increased expression of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-4 (NT-4), and tropomyosin receptor kinase (TrkA and TrkB) in SPG-178-promoted neurite outgrowth of motor neurons in vitro, and decreased inflammation and glial scar with use of SPG-178 in vivo. METHODS: We examined the effect of a self-assembling peptide, SPG-178, as a scaffold for neurite outgrowth of spinal motor neurons in vitro. An in vivo analysis was performed to evaluate if the SPG-178 scaffold attenuated or enhanced expression of various genes after spinal cord injury model rats. RESULTS: Expression of NGF, BDNF, NT-4, TrkA, and TrkB increased in SPG-178-promoted neurite outgrowth of motor neurons in vitro. In vivo, SPG-178 increased expression of glial cell line-derived neurotrophic factor and NGF, and decreased glial scar. CONCLUSION: This study provides new evidence for the role of SPG-178 as a scaffold in the spinal cord and suggests that this peptide is a neuroprotective factor that may serve as an alternative treatment for neuronal injuries. LEVEL OF EVIDENCE: 5.

Nogo receptor 1 is expressed in both primary cultured glial cells and neurons.

Nogo receptor (NgR) is common in myelin-derived molecules, i.e., Nogo, MAG, and OMgp, and plays important roles in both axon fasciculation and the inhibition of axonal regeneration. In contrast to NgR's roles in neurons, its roles in glial cells have been poorly explored. Here, we found a dynamic regulation of NgR1 expression during development and neuronal injury. NgR1 mRNA was consistently expressed in the brain from embryonic day 18 to postnatal day 25. In contrast, its expression significantly decreased in the spinal cord during development. Primary cultured neurons, microglia, and astrocytes expressed NgR1. Interestingly, a contusion injury in the spinal cord led to elevated NgR1 mRNA expression at the injury site, but not in the motor cortex, 14 days after injury. Consistent with this, astrocyte activation by TGFß1 increased NgR1 expression, while microglia activation rather decreased NgR1 expression. These results collectively suggest that NgR1 expression is enhanced in a milieu of neural injury. Our findings may provide insight into the roles of NgR1 in glial cells.

Analysis of cervical kyphosis and spinal balance in young idiopathic scoliosis patients classified by the apex of thoracic kyphosis.

PURPOSE: Sagittal balance has recently been the focus of studies aimed at understanding the correction force required for both coronal and sagittal malalignment. However, the correlation between cervical kyphosis and sagittal balance in AIS patients has yet to be thoroughly investigated. This study aimed to clarify the correlation between cervical alignment and spinal balance in patients with adolescent idiopathic scoliosis (AIS). Here, we hypothesized that cervical kyphosis patients can be classified into groups by the apex of thoracic kyphosis. METHODS: This study included 92 AIS patients (84 females, 8 males; mean age, 15.1 years). Patients were divided into the cervical lordosis (CL), cervical sigmoid (CS), or cervical kyphosis (CK) groups and further classified according to the apex of thoracic kyphosis into High (above T3), Middle (T4-T9), and Low (below T10) groups. RESULTS: There were 17 (18.5 %), 22 (23.9 %), and 53 (57.6 %) patients with CL, CS, and CK, respectively. In the CK group, 13 had CK-High, 35 had CK-Middle, and 5 had CK-Low. The C7 sagittal vertical axis (C7SVA) measurements were most backward in CK-High and most forward in CK-Low. The T5-12 kyphosis (TK) measurement was significantly lower in CK-High. CONCLUSIONS: Most AIS patients had kyphotic cervical alignment. Patients with CK can be classified as having CK-High, CK-Middle, or CK-Low according to the apex of thoracic kyphosis. CK-High is due to thoracic hypokyphosis with a backward balanced C7SVA. CK-Middle is well-balanced cervical kyphosis. CK-Low has forward-bent global kyphosis of the cervicothoracic spine that positioned the C7SVA forward.