Shigeto Ebata

Role of Weekly Teriparatide Administration in Osseous Union Enhancement within Six Months After Posterior or Transforaminal Lumbar Interbody Fusion for Osteoporosis-Associated Lumbar Degenerative Disorders: A Multicenter, Prospective Randomized Study.

Background: For elderly patients, posterior lumbar interbody fusion (PLIF) or transforaminal lumbar interbody fusion (TLIF) is usually performed to treat lumbar degenerative diseases. However, some patients exhibit pseudarthrosis following such procedures. The anabolic agent teriparatide is an approved treatment for promoting bone formation in osteoporotic patients. Our multicenter, prospective randomized study assessed the role of once-weekly teriparatide administration on patient outcomes following interbody fusion. Methods: Patients were females who were ≥50 years of age, had a bone mineral density (BMD) of <80% of the sex-matched young adult mean and/or previous spinal compression or femoral fractures, and had lumbar degenerative disease. Patients were randomly allocated to receive either weekly teriparatide, administered subcutaneously starting at week 1, for 6 months postoperatively (the teriparatide arm), or no teriparatide (the control arm). Blinded radiographic evaluations were performed using dynamic radiography and computed tomography (CT) and assessed by modified intention-to-treat analysis and per-protocol analysis. Clinical and neurological symptoms were evaluated using the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOA-BPEQ) and the Oswestry Disability Index (ODI). Results: Seventy-five patients were randomized to treatment, and 66 patients completed treatment. At 4 months postoperatively, bone fusion in the 2 center CT slices was significantly higher in the teriparatide arm compared with the control arm in the age-adjusted modified intention-to-treat analysis and was significantly higher at 6 months in the per-protocol analysis. Radiographic examinations showed no disc-space narrowing and no intervertebral disc instability. JOA-BPEQ and ODI results were improved postoperatively in both treatment arms. Conclusions: Weekly administration of teriparatide promoted bone formation at the surgical fusion site and decreased bone resorption, as indicated by bone metabolic marker results, within the early postoperative period. Our findings suggest that combining lumbar interbody fusion and teriparatide treatment may be an effective option for managing lumbar degenerative disease in elderly patients. Level of Evidence: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Lumbar ligamentum flavum hematoma treated with endoscopy.

Hematoma of the ligamentum flavum is a rare cause of neural compression, for which treatment has consisted of excising the hematoma via open surgical approaches, including total laminectomy or bilateral partial laminectomy. This article presents the first report of a microscope-assisted endoscopic decompression to resect a hematoma of the ligamentum flavum.A 52-year-old man presented with back and leg pain, as well as difficulty initiating micturation. Magnetic resonance imaging demonstrated an epidural mass at L5/S1 that was continuous with the facet joint. Visualization was obtained via an endoscope, and a reddish tan-brown solid mass was found beneath the ligamentum flavum. Thorough decompression of the cauda equine and nerve roots was undertaken. The patients radicular leg pain and bladder function improved soon after the decompression. Histological examination of the ligamentum flavum revealed a consolidated hematoma with granulomatous change.A review of the English literature revealed 29 cases of hematoma in the lumbar ligamentum flavum. Surgical decompression in these patients was accomplished with a standard open approach through hemilaminectomy (n=11), total laminectomy (n=10), or laminectomy followed by posterior fixation (n=3). The literature review did not identify any case of hematoma of the lumbar ligamentum flavum that was treated endoscopically. We expect our case may expand the indications for the endoscope in spine surgery.

Application of neurite orientation dispersion and density imaging or diffusion tensor imaging to quantify the severity of cervical spondylotic myelopathy and to assess postoperative neurologic recovery

BACKGROUND CONTEXT Surgical outcome and the severity of cervical spondylotic myelopathy (CSM) are unpredictable and cannot be estimated by conventional anatomical magnetic resonance imaging (MRI). The utility of diffusion tensor imaging (DTI) to quantify the severity of CSM and to assess postoperative neurologic recovery has been investigated. However, whether conventional DTI should be applied in a clinical setting remains controversial. Neurite orientation dispersion and density imaging (NODDI) is a recently introduced model-based diffusion-weighted MRI technique that quantifies specific microstructural features related directly to neuronal morphology. However, there are as yet few clinical applications of NODDI reported. Indeed, there are no reports to indicate NODDI is useful for diagnosing CSM. STUDY DESIGN This is a retrospective cohort study using consecutive patients. PURPOSE The objective of this study was to evaluate the utility of NODDI and conventional DTI for detecting changes in the spinal cord microstructure. In particular, this study aimed to quantify the preoperative severity of CSM and to assess postoperative neurologic recovery from this myelopathy. PATIENT SAMPLE We included 27 consecutive patients with a nontraumatic cervical lesion from CSM who underwent laminoplasty at a single institution between April 2012 and April 2015. The patients underwent MRI before and approximately 2 weeks after surgery. OUTCOME MEASURES In addition to conventional DTI metrics, we evaluated the intracellular volume fraction (ICVF) and the orientation dispersion index (ODI), which are metrics derived from NODDI. The 10-second grip and release test and the Japanese Orthopaedic Association scoring system were used before and 1 year after surgery to assess neurologic outcome. MATERIALS AND METHODS Neurite orientation dispersion and density imaging and conventional DTI values were measured at the C2-C3 intervertebral level (control value) and at the most compressed levels (C3-C7 intervertebral levels) were measured. The changes in these values pre- and postoperative were demonstrated. Correlations between NODDI and conventional DTI values and clinical outcome were determined. RESULTS Preoperative fractional anisotropy was significantly correlated with the severity of neural damage, but not with postoperative neurologic recovery. No significant correlation could be found between the preoperative ICVF, the ODI, the apparent diffusion coefficient, and the severity of the preoperative neurologic dysfunction. Preoperative ICVF was most strongly correlated with the severity of neurologic dysfunction and postoperative neurologic recovery. CONCLUSIONS Conventional DTI may be applied clinically to assess the severity of myelopathy. Neurite orientation dispersion and density imaging may be more valuable than conventional DTI to predict outcome following surgery in patients with CSM.

Swallowing function after occipitocervical arthrodesis for cervical deformity in patients with rheumatoid arthritis

BACKGROUND Some patients develop dysphagia after OC arthrodesis with RA. A previous report has indicated that establishing appropriate occipito-C2 is important for avoiding these side effects. However, a more recent report has demonstrated that the O-C2 angle did not have a significant effect on the incidence of postoperative dysphagia. OBJECTIVE To investigate the swallowing function of patients with rheumatoid arthritis (RA) before and after they underwent occipitocervical (OC) fusion. METHODS The study was performed in collaboration with the Departments of Orthopaedic, Otorhinolaryngology, and Rehabilitation. Seven consecutive patients (3 men and 4 women; mean age, 66.4 years) with RA-induced upper cervical deformity were enrolled from 2013 to 2014. The patients underwent deglutition analysis, which was performed by otorhinolaryngologists, before and after surgery, and comprised videofluoroscopy and fiberoptic endoscopy. We examined the relationship between imaging studies and swallowing function. RESULTS Preoperatively, subjective dysphagia was reported by 2 patients. Videofluoroscopy identified dysmotility of the epiglottis and incomplete closure of the laryngeal inlet in 2 patients, with contrast medium entering the larynx, and endoscopy identified food residue in the larynx of 1 patient during swallowing evaluation. Postoperatively, 2 patients with preoperative impaired deglutition showed dysphagia. Imaging examinations of the 2 patients revealed a 10°-reduction in the O-C2 angle of 1 patient, but the angle was unchanged in the other patient. CONCLUSIONS To the best of our knowledge, this is the first report to evaluate swallowing function before and after O-C3 arthrodesis. The preoperative O-C2 angle was unchanged after surgery. Impairment of deglutition may be closely associated with air leakage from the oropharynx due to impaired mobility of the soft palate. Because the precise mechanism of dysphagia has not been fully elucidated, further study using dynamic videofluoroscopy and videoendoscopy is needed to examine the swallowing mechanism.

Instability of treated vertebrae after balloon kyphoplasty causing paraparesis in osteoporotic vertebral compression fracture: a report of two cases

PurposeTo describe two unique cases of osteoporotic vertebral compression fracture (OVCF) treated with balloon kyphoplasty (BKP) that were complicated by spinal instability and resultant lower extremity paraparesis.MethodsKyphoplasty was performed in two patients with OVCF that had persistent back pain despite a course of conservative care. Immediately following BKP, both patients had a marked improvement in back pain. However, they developed progressive bilateral lower extremity weakness. Lateral spine flexion–extension radiographs demonstrated instability, and polymethyl methacrylate did not adhere to the endplate of the treated vertebrae.ResultsBoth the patients underwent a hybrid fixation without a decompression. Postoperatively, both of them demonstrated gradual improvement in their neurological exam.ConclusionsTo the best of our knowledge, this is the first report describing the development of spinal instability with resultant delayed paraplegia following BKP. This case report demonstrates another cause of neurological decline following BKP, in the absence of cement leakage.

Postoperative intervertebral stabilizing effect after cervical laminoplasty

BACKGROUND We previously demonstrated short length of rest with a cervical orthosis obtained a decreased tendency for neck or shoulder pain, neck stiffness, and impairment of cervical alignment after cervical laminoplasty. Postoperative maintenance of cervical motion may result in intervertebral instability and poor surgical outcomes. OBJECTIVE The purpose of this study was to compare the postoperative fusion rate, range of motion (ROM), vertebral listhesis, and surgical outcomes with the duration of rest with a cervical orthosis. METHODS We conducted cervical laminoplasty on 66 patients with spondylotic myelopathy. All patients were followed for at least two years. Patients remained in bed for two weeks and wore a cervical orthosis for eight weeks postoperatively, postoperative bed rest for seven days and use of an orthosis for four weeks, or postoperative bed rest for five days followed by use of an orthosis for two weeks were assigned. RESULTS Long rest with a cervical orthosis produced multiple unions and limitation of cervical ROM, resulting in postoperative neck pain. Short rest maintained motion at multiple disc levels. There was no marked difference in neurogenic outcomes between short and long rest. CONCLUSIONS A short rest period with a cervical orthosis is recommended to maintain cervical motion free from neck pain.

Integrated anatomy of the neuromuscular, visceral, vascular, and urinary tissues determined by MRI for a surgical approach to lateral lumbar interbody fusion in the presence or absence of spinal deformity

Introduction To comprehensively investigate the anatomy of the neuromuscular, visceral, vascular, and urinary tissues and their general influence on lateral lumbar interbody fusion (LLIF) surgery in the presence or absence of spinal deformity. Methods We retrospectively reviewed 100 consecutive surgery cases for lumbar degenerative disease of patients aged on average 70.5 years and of which 67 were women. A sagittal vertical axis deviation of more than 50 mm was defined as adult spinal deformity (ASD: 50 patients). The degenerative disease of the other patients was defined as lumbar spinal stenosis (LSS: 50 patients). We analyzed the relative anatomical position of the psoas major muscle, lumbar plexus, femoral nerves, inferior vena cava, abdominal aorta and its bifurcation, ureter, testicular or ovarian artery, kidney and transverse abdominal muscle in patients with ASD or with LSS, using preoperative magnetic resonance imaging (MRI). Results For patients with ASD, the L4-5 intervertebral disk was closer to the lumbar nerve plexus than it was in those with LSS (p < 0.0001), and a rising psoas sign at the L4-5 disk was significantly more frequent in patients with ASD than in those with LSS (p < 0.05). The aortic bifurcation frequently appeared at the level of L4-5 in patients with either degenerative disease, so the common iliac artery may pass near the disk. The inferior vena cava passed closer to the center of the L4-5 disk in patients with ASD than it did in those with LSS (p < 0.05). The transverse abdominal muscle at L2-3, L3-4, and L4-5 was closer to and less than 3 mm from the kidneys in many more patients with ASD than was the case for patients with LSS (p = 0.3, p < 0.05, p = 0.29, respectively). Conclusions We recommend careful preoperative MRI to determine the location of organs to help to avoid intraoperative complications during LLIF surgery, especially for patients with ASD.

Adequate cage placement for a satisfactory outcome after lumbar lateral interbody fusion with MRI and CT analysis

Introduction Through an extreme lateral retroperitoneal and transpsoas approach to intervertebral disc and fusion surgery, a large lordosis cage can be placed for solid and stable intervertebral fusion and to provide strong anterior support, disc height restoration, favorable alignment, and indirect nerve decompression. However, appropriate placement of the interbody cage remains insufficiently researched. We sought to determine both appropriate cage placement as well as other factors affecting nerve decompression in extreme lateral interbody fusion (XLIF) surgery. Methods We included 53 consecutive patients suffering from lumbar degenerative diseases with an indication for XLIF. Radiographic analysis using a sagittal computed tomography (CT) and axial magnetic resonance imaging (MRI) views was conducted to determine intervertebral disc height and angle, degree of disc bulging and thickness of the flavum, the area of the dural tube, cage height, pre- and postoperative disc bulging, change of disc bulging after surgery, cage subsidence, and cage placement at the rostral and caudal endplates. Results Intervertebral disc height and angle were significantly increased at all levels (L2/3, 3/4, 4/5) (p < 0.05). The area of the dural tube was significantly increased (p < 0.05), whereas the degree of disc bulging and thickness of the flavum were significantly decreased at all disc levels (p < 0.05). The enlarged area of the dural tube showed significant correlation with increased disc height (p = 0.019), preoperative flavum thickness (p = 0.008), change of flavum thickness (p < 0.0001), and cage placement at the rostral endplate (p = 0.014). Conclusions A decrease in flavum buckling is more important than disc protrusion as a consideration for obtaining indirect decompression. Central placement may be advantageous for indirect decompression.

Risk factors for clinically relevant loosening of percutaneous pedicle screws

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.

Spinal Metastasis of Well-Differentiated Liposarcoma Component in Retroperitoneal Dedifferentiated Liposarcoma Treated by Minimally Invasive Surgery

Case Generally, well-differentiated liposarcoma (WDL) has recurrence potential but lacks metastatic potential. We present a rare case of spinal metastasis of WDL component in retroperitoneal dedifferentiated liposarcoma (DDL) treated by tumor curettage and L1 laminectomy followed by percutaneous pedicle screw fixation. Histological examination showed metastasis of the WDL component of DDL. The patient was ambulatory until death. Conclusion To our knowledge, no case of spinal metastasis of WDL component in retroperitoneal DDL has been reported. We should carefully consider characteristics of DDLs during treatment. Minimally invasive surgery may be a powerful tool in patients with spinal metastasis.