Intervertebral disc degeneration is a well-known cause of disability, the result of which includes neck and back pain with associated mobility limitations. The purpose of this article is to provide an overview of the known molecular mechanisms through which intervertebral disc degeneration occurs as a result of complex interactions of exogenous and endogenous stressors. This review will focus on some of the identified molecular changes leading to the deterioration of the extracellular matrix of both the annulus fibrosus and nucleus pulposus. In addition, we will provide a summation of our current knowledge supporting the role of associated DNA and intracellular damage, cellular senescence's catabolic effects, oxidative stress, and the cell's inappropriate response to damage in contributing to intervertebral disc degeneration. Our current understanding of the molecular mechanisms through which intervertebral disc degeneration occurs provides us with abundant insight into how physical and chemical changes exacerbate the degenerative process of the entire spine. Furthermore, we will describe some of the related molecular targets and therapies that may contribute to intervertebral repair and regeneration.
Postoperative C5 palsy (C5 palsy) is defined as de novo or aggravating muscle weakness mainly at the C5 region with slight or no sensory disturbance after cervical spine surgery. The features of C5 palsy are as follows: 1) one-half of patients are accompanied by sensory disturbance or intolerable pain at the C5 region; 2) 92% of patients have hemilateral palsy; 3) almost all palsy occurs within a week after surgery; 4) the incidence is almost the same between the anterior and posterior approaches to the cervical spine; 5) the prognosis is relatively good even in patients with severe muscle weakness. Even now, the precise causes of C5 palsy have not yet been revealed. From the viewpoint of the kinds of nerve tissue involved, the uncertain causes of C5 palsy are divided into two theories: 1) the segmental spinal cord disorder theory and 2) the nerve root injury theory. In the former, the segmental spinal cord, particularly the anterior horn cells, is thought to be chemically damaged because of preoperative ischemia and/or the aggression of reactive oxygen during postoperative reperfusion. By contrast, in the latter, the anterior rootlet and/or nerve root are believed to be mechanically damaged because of compression force and/or distraction force. In this theory, the features of C5 palsy can be well explained from anatomical viewpoints. Additionally, various countermeasures have been proposed, such as the intermittent relaxation of the tension of the hooks to the multifidus muscles during surgery; prophylactic foraminotomy to decompress C5 nerve root; prevention of excessive posterior shift of the spinal cord, which may cause the tethering effect of the nerve root; and prevention of excessive postoperative lordotic alignment of the cervical spine. These countermeasures have been proved effective, and may support the nerve root injury theory as the main conjectured theory on the causes of C5 palsy.
Although adult spinal deformity (ASD) has become a global health problem, the classification system and optimal surgical treatment for ASD is yet to be standardized worldwide. A significant part of the population, as high as 10%, in industrialized societies will be aged above 65 years within the next 10 years. Herein, a systematic review of the scientific literature related to the classification and treatment of ASD was conducted wherein historical to the most recent classifications of ASD were reviewed. By discussing the benefits and limitations of the previous classification systems and considering the factors affecting the clinical outcomes of surgical treatment of ASD, this article would like to propose future directions for the development of a new classification system for ASD.
Introduction: The purpose of this study was to investigate the relationship between postoperative enlargement of the dural sac cross-sectional area at the symptomatic level and neurological improvements after laminoplasty.
Methods: The cross-sectional areas of the dural sac at the symptomatic level before and after laminoplasty and the expansion ratio (post-/preoperative cross-sectional area) were measured using magnetic resonance imaging in patients with ossification of the posterior longitudinal ligament (OPLL) (n = 25) and patients with cervical spondylotic myelopathy (CSM) (n = 49). The relationships between the expansion ratio and the Japanese Orthopedic Association (JOA) score, JOA Cervical Myelopathy Evaluation Questionnaire (JOACMEQ), and postoperative laminae morphology were investigated.
Results: In the OPLL group, the expansion ratio was significantly positively correlated with the postoperative JOA score (P = 0.025), recovery rate of the JOA score (P = 0.026), and postoperative change in lower extremity sensory function according to the JOA score (P = 0.0375); furthermore, patients whose JOACMEQ responses indicated positive outcomes for lower extremity function had a significantly larger expansion ratio than patients with negative results (P = 0.027). In the CSM group, the expansion ratio showed no correlation with the JOA and JOACMEQ scores. The expansion ratio was significantly positively correlated with the width between bilateral gutters in both CSM (P = 0.025) and OPLL (P = 0.0451). In the OPLL group, the expansion ratio in those with a gutter position of less than 0.8 was significantly smaller than that those with a gutter position of more than 0.8 (P = 0.0156). However, there was no correlation between the gutter position and the recovery rate of the JOA score.
Conclusions: In OPLL, insufficient enlargement of the cross-sectional area of the dural sac at the symptomatic level leads to poor neurological improvements after laminoplasty.
Introduction: Cervical spinal cord injury without bone injury (SCIWOBI) is a common cervical injury in the elderly population and is most likely to occur at the C3/C4 level. Respiratory dysfunction (RD) related to the damage of the spinal respiratory center, which is close to the C4 segment, is one of the greatest obstacles in improving the activities of daily living of patients with severe paralysis. We evaluated the time course of RD and motor function in cervical SCIWOBI to identify effective medical strategies.
Methods: We followed 54 patients (49 men, 5 women; mean age: 65 years old) who were treated for SCIWOBI at our medical center from 2011 to 2014. The patients were evaluated within 72 hours of injury and were monitored for at least 12 weeks. All patients began respiratory-muscle training the day after admission regardless of whether they were treated conservatively or surgically. The percent vital capacity (%VC), forced expiratory volume (FEV) in one second/forced vital capacity ratio (FEV 1.0%), and American Spinal Injury Association motor score (MS) were recorded at admission and again at weeks 4 and 12. We calculated the %VC rate of change and the MS improvement rate over the entire period.
Results: Fifty patients (92.6%) had restrictive ventilatory impairment at admission. The %VC correlated with the upper- and lower-limb MSs at admission, and the %VC and upper- and lower-limb MSs had improved by weeks 4 and 12 after the injury. The %VC rate of change was significantly correlated with the rate of improvement in lower-limb MS throughout the entire period.
Conclusions: Lung capacity decreased in SCIWOBI owing to respiratory-muscle paralysis and upper- and lower-limb motor paralyses. Lung capacity improved as the lower limbs recovered their motor function. Respiratory rehabilitation should be continued for at least 12 weeks after SCIWOBI.
Introduction: We describe 5 patients who underwent operative treatment for arachnoid web (AW) and discuss the postoperative clinical outcome in each case. AW is an extremely rare disease that causes cord compression and syringomyelia in the thoracic spine. To date, 14 cases only of AW have been reported, and the effect of surgical intervention on clinical and radiologic outcomes is unknown.
Methods: Five patients who underwent surgical treatment for AW were retrospectively reviewed. The clinical outcomes were evaluated using the thoracic Japanese Orthopaedic Association (T-JOA) score. Preoperative and postoperative images were reviewed.
Results: All the patients presented with spastic gait and numbness in the lower extremities. Two patients also presented with bladder-bowel dysfunction (BBD). AW, or the so-called "scalpel" sign, was seen dorsally in the thoracic spine on magnetic resonance imaging in all the patients. Syringomyelia adjacent to the web was observed in 4 patients. Fenestration and web resection without instrumentation was performed in all the cases. Overall, significant improvement was seen in locomotion and the total T-JOA score postoperatively. However, numbness in the lower extremities improved in 2 patients but was unchanged in 3 cases. BBD was ameliorated in 1 patient but remained unchanged in the other patient.
Conclusions: Our experience suggests that surgical treatment, including the another patient and resection of the web, can correct the flow dynamics of cerebrospinal fluid and allow neurologic recovery, in particular locomotion, in patients with AW.
Introduction: Recent advances in diagnostic imaging, such as computed tomography (CT) and magnetic resonance imaging (MRI), have allowed early diagnosis of lumbar spondylolysis (LS). However, few outpatient clinics are equipped with such imaging apparatuses and must rely on plain radiographs for the diagnosis of LS. The aim of this retrospective study was to identify how accurately fracture lines can be detected on plain radiographs in patients with LS.
Methods: Patients with a diagnosis of LS were staged as early, progressive, or terminal. We evaluated whether fracture lines could be detected on plain radiographs and compared the detection rates under the following conditions: two directions including anteroposterior and lateral views (2 views), four directions including both oblique views (4 views), four directions including dynamic lateral views (4-D views), and all six directions (6 views).
Results: In early LS, the fracture line detection rate was 11.4% using 2 views, 20.5% using 4 views and 4-D views, and 22.7% using 6 views. In progressive LS, the fracture line detection rate was 54.2% using 2 views, 70.8% using 4-D views, 75.0% using 4 views, and 79.2% using 6 views. The respective detection rates for terminal LS were 85.0%, 100%, 100%, and 100%.
Conclusions: Although terminal LS was diagnosed accurately on plain radiographs in all patients, the detection rates were only 22.7% and 79.2% in patients with early and progressive LS, respectively. These results suggest that plain radiographic films can no longer be considered adequate for early and accurate diagnosis of LS. Advanced imaging procedures, such as MRI in the early diagnosis or CT for persistent cases, are recommended to obtain an accurate diagnosis of early stage LS in pediatric patients requiring conservative treatment to achieve bony healing.
Introduction: Favorable short-term outcomes have been reported following muscle-preserving interlaminar decompression (MILD), a less invasive decompression surgery for lumbar spinal canal stenosis (LSCS). However, there are no reports of mid- to long-term outcomes. The purpose of this study was to evaluate the clinical outcomes five or more years after treatment of LSCS with MILD.
Methods: Subjects were 84 cases with LSCS (44 males; mean age, 68.7 years) examined five or more years after MILD. All patients had leg pain symptoms, with claudication and/or radicular pain. The patients were divided into three groups depending on the spinal deformity: 44 cases were without deformity (N group); 20 had degenerative spondylolisthesis (DS group); and 20 had degenerative scoliosis (DLS group). The clinical evaluation was performed using Japanese Orthopedic Association (JOA) scores, and revision surgeries were examined. Changes in lumbar alignment and stability were evaluated using plain radiographs.
Results: The overall JOA score recovery rate was 65.5% at final follow-up. The recovery rate was 69.5% in the N group, 65.2% in the DS group, and 54.0% in the DLS group, with the rate of the DLS group being significantly lower. There were 16 revision surgery cases (19.0%): seven in the N group (15.9%), three in the DS group (15.0%) and six in the DLS group (30.0%). There were no significant differences between pre- and postoperative total lumbar alignment or dynamic intervertebral angle in any of the groups, slip percentage in the DS group, or Cobb angle in the DLS group.
Conclusions: The mid-term clinical results of MILD were satisfactory, including in cases with deformity, and there was no major impact on radiologic lumbar alignment or stability. The clinical outcomes of cases with degenerative scoliosis were significantly less favorable and the revision rate was high. This should be taken into consideration when deciding on the surgical procedure.
Introduction: Nonsteroidal anti-inflammatory drugs (NSAIDs) are the first-line treatment for acute lumbar radicular pain accompanying lumbar disc herniation (LDH), but their effects are minimal. The purpose of this study was to evaluate the efficacy and safety of pregabalin (PGB) as an alternative therapy for this condition.
Methods: Patients with acute lumbar radicular pain accompanying LDH were randomly administered either NSAIDs plus PGB (30 patients) or NSAIDs alone (30 patients) for up to 4 weeks. The primary outcome was leg pain at 2 and 4 weeks. Secondary outcomes were reduction in sleep disturbances and patient global impressions of change (PGIC) at 2 and 4 weeks.
Results: Four patients in the NSAIDs plus PGB group were deemed ineligible and excluded from the study. Fewer sleep disturbances were reported by patients administered NSAIDs plus PGB compared with the NSAID monotherapy group at both 2 and 4 weeks. Additionally, the NSAIDs plus PGB group showed greater improvement in pain than the NSAID monotherapy group at 4 weeks, although this difference was not significant. PGIC was also significantly better in the NSAIDs plus PGB group than in the NSAID monotherapy group at 4 weeks. The incidence of adverse events was significantly greater in the NSAIDs plus PGB group than in the NSAID monotherapy group.
Conclusions: The combination of NSAIDs plus PGB is more effective against sleep disturbance than NSAIDs alone in patients with acute LDH, although the control of sciatic pain is minimal. Patients reported satisfactory recoveries could also be obtained, and thus, this combination therapy could be a good option for the conservative treatment of acute lumbar radicular pain, including LDH.
Introduction: Although there has been a dramatic improvement in the outcomes of conservative treatment to achieve bony healing due to advances in diagnostic and therapeutic tools, in some patients, the results continue to be unfavorable. The purpose of this study was to investigate the outcomes of conservative treatment in pediatric patients with stress fractures occurring in the lamina that are discontinuous due to a contralateral pars defect or spina bifida occulta (SBO).
Methods: The medical records at our outpatient clinic for 103 consecutive patients (83 boys, 20 girls) with lumbar spondylolysis (LS) were reviewed to identify those who had presented with a stress fracture and a contralateral pars defect or with SBO at the affected lamina level.
Results: Twelve patients (11 boys, 1 girl) of mean age 12.3 (range 8-16) years were identified. Except for 1 stress structure that occurred at L4, all the stress fractures occurred at L5. Six patients had a pars defect, 5 had SBO, and 1 had both. Two of the 6 patients with a contralateral pars defect had early LS, 3 had progressive LS, and 1 had a pedicle fracture. The fracture healed in 1 (50%) of the 2 patients with early LS and in the patient with the pedicle fracture, but did not heal in any of the patients with progressive LS. Two of the 5 patients with SBO at the affected lamina level had early LS and 3 had progressive LS. The bony healing rate was 100% in the 2 patients with early LS and 66.7% in the 3 patients with progressive LS. The fracture healed in the patient with progressive LS and both a pars defect and SBO at the affected lamina.
Conclusions: Contralateral pars defect remains an unfavorable factor for bony healing discontinuous laminar stress fractures.
Introduction: This study aimed to compare the clinical and radiological results of transforaminal lumbar interbody fusion (TLIF) with a boomerang-shaped cage and traditional posterior lumbar interbody fusion (PLIF) according to fused level and elucidate whether TLIF could replace PLIF at all lumbar levels.
Methods: The study investigated 128 patients with lumbar spondylolisthesis who underwent a single-level TLIF or traditional PLIF. Intraoperative blood loss, operative time, and recovery rate were analyzed. Percent slip, disc height, and local lordosis at the fused level were measured using X-ray images from preoperation to the final follow-up.
Results: No significant differences in recovery rate were observed at any level. The operative time and intraoperative blood loss were significantly less in the TLIF group at the L4/5 and L5/S1 levels. There were no significant differences in disc height or local lordosis at the L3/4 and L4/5 levels, and a satisfactory level of maintenance after the operation was achieved in both groups. However, at the L5/S1 level, postoperative maintenance after TLIF could not be achieved, and the obtained disc height and local lordosis in TLIF significantly decreased.
Conclusions: Compared with traditional PLIF, TLIF was a less invasive procedure with a shorter operative time and lesser blood loss. TLIF could obtain similar local lordosis and disc height as PLIF at the L3/4 and L4/5 levels. At the L5/S1 level, the postoperative maintenance of local lordosis and disc height after TLIF was inferior to that after PLIF. On the basis of our results, we do not recommend performing TLIF at only the L5/S1 level.
Introduction: (1) To evaluate the influence of pedicle screw loosening on clinical outcomes; (2) to clarify the association between the pull-out length and screw loosening 1 year after surgery; and (3) to determine radiographically which screw parameters predominantly influence the pull-out resistance of screws.
Methods: We analyzed 32 consecutive patients who underwent minimally invasive lumbar or thoracic spinal stabilization by intraoperative three-dimensional computed tomography (CT)-guided navigation without anterior reconstruction and were followed up for 1 year. The screw pull-out length was measured on axial CT images obtained both immediately after screw insertion and postoperatively. Loosening of screws and clinical outcomes were evaluated radiographically, clinically, and by CT 1 year after surgery.
Results: There were no significant differences in the mean age, sex, bone mineral density, mean stabilized length, and smoking habits of patients with (+) or without (−) loosening. The Oswestry Disability Index and the lumbar visual analog scale 1 year after surgery were significantly higher in patients with loosening (+) than in those without (−). The overall pedicle screw pull-out rate was 16.2% (47/290) of screws and the overall screw loosening rate was 15.2% (44/290) of screws. Screws with loosening (+) had significantly lower (axial) trajectory angles and higher screw pull-out lengths than those without (−). Approximately 82% of loosened screws had been pulled out during rod connection.
Conclusions: A lower axial trajectory and an increased screw pull-out length after rod reduction are crucial risk factors for screw loosening.
Introduction: Spinal subdural abscess (SSA) or empyema is a rare pathology and its exact incidence is unknown. Staphylococcus aureus (S aureus) is the most frequently responsible organism. The patients with SSA may have one or more predisposing immunosuppressive conditions. However, here we report a rare case of SSA following food intoxication without any significant comorbidities.
Case Report: A 42-year-old healthy man presenting with fever, severe low back pain (LBP), and trunk motion restriction was transferred to our hospital. He had been treated for an unknown fever after food intoxication in another hospital. Eighteen days earlier, he and his colleagues together ate raw horse meat and briefly boiled chicken breast. They all had food intoxication on the following day. Subsequently, our patient began to have a high fever and severe LBP. Laboratory data showed leukocytosis of 16,000/mm3. Also, the C-reactive protein was elevated to 26 mg/dL. The blood culture result was consistent with S aureus. Magnetic resonance imaging (MRI) showed focal epidural fluid collection that appeared contiguous with the subdural fluid collection through a dural defect in the axial plane on T2-weighted (T2W) images. An emergent surgery was performed. Frank pus was expressed from the epidural space as well as from the subdural space through the defect. The pus later grew S aureus. The patient was started on antibiotic therapy postoperatively. The patient completely recovered 1 month after surgery.
Conclusions: SSA following food intoxication is a very rare case. SSA can be identified with a small dural defect and the intrathecal fluid collection compressing the cauda equina in the axial plane on T2W magnetic resonance images. Having suspicion of epidural abscess and likewise subdural abscess and making an early diagnosis using MRI and an emergent surgery are important when the clinician notices a febrile patient with severe LBP and trunk motion stiffness.
This was a study of the case of a 60-year-old woman who presented with a six-month history of headache and numbness radiating to the right arm. MRI revealed a fusiform intramedullary spinal tumor spanning C2 to C5 at the hospital where she first presented. As her right upper limb weakness had presented gradually, she visited our hospital after one and a half years. Neurological examination revealed muscle weakness in the right deltoid, but no sensory disturbance.
The patient underwent a C2-C6 total laminectomy and posterior midline myelotomy from the posterior median fissure of the spinal cord. The intraoperative histological diagnosis was glioma.
Pathological findings in low magnification demonstrated clusters of small uniform nuclei embedded in a dense and fibrillary matrix in hematoxylin-eosin staining (H.E.). On immunohistochemical staining, the tumor cells were weakly positive for glial ﬁbrillary acidic protein (GFAP), but negative for the epithelial membrane antigen (EMA). The histopathological ﬁndings were consistent with the diagnosis of a subependymoma. However, the MIB-1 labeling index was of moderately high level up to approximately 8%.
In this case, we performed total resection because the tumor had rapidly increased in size and was of atypical form in histological findings.
It should be minded that some of subependymomas have a possibility of rapidly increasing in size with progressing neurological deficits.
Introduction: The lateral lumbar interbody fusion (LLIF) surgical approach is minimally invasive and safely accesses the target region. Therefore, it is widely used in cases of lumbar spinal stenosis and spinal deformity. Intraoperative neuromonitoring is necessary to avoid nerve injury, whereas postoperative anterior thigh symptoms are not necessarily prevented.
Technical Note: In our institute, 85 LLIF operations have been performed. The first 30 cases were excluded from the present study to avoid surgical learning curve effects; conventional monitoring was used in 30 cases, whereas a new method with a probe to monitor intramuscular potential was used in 25 other cases. Anterior thigh symptoms and motor deficits were assessed postoperatively. The location of the electromyographic threshold decrease was at the posterior part of the disc at L2-3, but at the anterior part at L4-5. Compared with conventional monitoring, the new intramuscular monitoring significantly decreased the prevalence of motor deficits of the iliopsoas at 1 day and 30 days; anterior thigh pain at 1 day, 30, and 90 days; and anterior thigh numbness at 30 and 90 days postoperatively.
Conclusions: Compared with conventional monitoring, the new intramuscular monitoring with a less invasive probe may reduce anterior thigh symptoms.