Comparison of facet fusion rates and clinical outcomes between cortical bone trajectory screw and percutaneous pedicle screw fixation for degenerative lumbar spondylolisthesis.

BACKGROUND CONTEXT: Cortical bone trajectory (CBT) screws have been introduced as an alternative technique for pedicle screw (PS) insertion because they have greater contact with the cortex and a greater uniaxial pullout load than traditional PS. CBT screwing can also minimize muscle dissection. However, CBT screws and traditional PSs have not yet been compared in terms of fusion rates and clinical outcomes for particular operative procedures. PURPOSE: This study aimed to assess the fusion rate and clinical outcomes of facet fusion (FF) fixed with CBT screws (CBT-FF) and to compare them with those of FF fixed with percutaneous PS (PPS-FF). STUDY DESIGN: Retrospective study. PATIENT SAMPLE: Records of 68 patients who underwent CBT-FF for single-level degenerative lumbar spondylolisthesis (DLS) with at least 1 year of follow-up were retrospectively reviewed. The control group comprised 143 patients who underwent PPS-FF under the same conditions. OUTCOME MEASURES: Computed tomography was performed to confirm fusion. Therapeutic effectiveness was assessed as a clinical outcome using the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ), Roland-Morris Disability Questionnaire (RMDQ), and visual analog scale (VAS) preoperatively and 1 year postoperatively. The rate of revision surgery was also calculated. Intraoperative blood loss was measured. METHODS: Fusion rate, clinical outcomes, revision surgery rate, and intraoperative blood loss of CBT-FF and PPS-FF were compared. RESULTS: The CBT-FF and PPS-FF fusion rates were 91.2% and 90.1%, respectively. The JOABPEQ category scores demonstrated therapeutic effectiveness in 74.5% and 77.1% of the patients for low back pain; the corresponding proportions for walking ability were 84.7% and 89.3%, respectively. No significant differences in therapeutic effectiveness were observed for any category, including the RMDQ and VAS scores for buttock and lower limb pain. Three patients required revision surgery for adjacent segment disease between 6 months and 3.5 years after CBT-FF (revision surgery rate, 4.4%), whereas the revision surgery rate for PPS-FF was 6.3% (9/143 cases). Average intraoperative blood loss was significantly less in the CBT-FF group than in the PPS-FF group. CONCLUSIONS: Both procedures were equally useful in terms of fusion rate and clinical outcomes for DLS management.

Quantitative evaluation of the lumbar ligamentum flavum using MRI T2-mapping: Efficacy of its clinical application in patients with lumbar spinal stenosis.

OBEJECTIVE: To perform a magnetic resonance imaging T2-mapping of the ligamentum flavum in healthy individuals and patients with lumbar spinal stenosis scheduled for surgery and compare the T2 relaxation times. SUBJECTS AND METHODS: The T2 relaxation time of the ligamentum flavum was compared among 3 groups, healthy young individuals (H group (age< 50)), healthy middle-aged and older individuals (H group (age≥50)), and patients with lumbar spinal stenosis (L group). Additionally, the thickness of the ligament was measured in the axial image plane, and the occupied area ratio of each fiber was measured by staining the surgically obtained ligament, and each was correlated with the T2 relaxation time. We also evaluated the adhesion of the ligamentum flavum with the dura mater during the surgery. RESULTS: The T2 relaxation times were significantly prolonged in H group (age ≥50) and L group (P < 0.001) compared to H group (age<50). The relationship between collagen fiber and T2 relaxation times was significantly positive (r = 0.720, P < 0.001). Moreover, the relaxation times were significantly prolonged in those with adhesion of the ligamentum flavum with the dura mater (P < 0.05). The cut-off for the relaxation time was 50 ms (sensitivity: 62.50%, false positive rate: 10.8%). CONCLUSION: Healthy middle-aged and older individuals and patients with lumbar spinal stenosis and adhesion of the ligamentum flavum with the dura mater have prolonged T2 relaxation times. Hence, the adhesion between the ligamentum flavum and dura mater should be considered in cases with a relaxation time ≥50 ms.

Good 5-year postoperative outcomes after facet fusion using a percutaneous pedicle screw system for degenerative lumbar spondylolisthesis.

Many authors have reported no significant differences in clinical outcomes between posterolateral fusion (PLF) and interbody fusion, as well as satisfactory long-term outcomes after PLF. Facet fusion (FF), a minimally invasive evolution of PLF, has also resulted in good clinical outcomes. This study aimed to assess the clinical outcomes 5 years after FF for degenerative lumbar spondylolisthesis (DLS) and determine whether good clinical outcomes were maintained after FF. Records of 115 patients who underwent FF for single-level DLS with at least 5 years of follow-up were retrospectively studied. The therapeutic effectiveness of FF was assessed as a clinical outcome using the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ), the Roland-Morris Disability Questionnaire (RMDQ), and the visual analogue scale (VAS) preoperatively and at 1 and 5 years postoperatively. Computed tomography was performed for fusion confirmation. The revision surgery rate was also evaluated. The JOABPEQ category scores demonstrated therapeutic effectiveness in 81.7% of patients at 1 year postoperatively and 81.4% of patients at 5 years postoperatively for low back pain; the corresponding proportions for walking ability were 93.8% and 86.6%, respectively. There were no significant differences in therapeutic effectiveness at 1 and 5 years postoperatively for any category, including the RMDQ and VAS scores. The fusion rate was 90.4% at the final follow-up. Four patients required revision surgery for adjacent segment disease 1-5 years after the first surgery (revision surgery rate, 3.5%). Good clinical outcomes were maintained 5 years after FF, and FF had an extremely low revision surgery rate.

Good clinical outcomes in nonunion cases after facet fusion with a percutaneous pedicle screw system for degenerative lumbar spondylolisthesis.

There are many satisfactory long-term outcomes after posterolateral fusion (PLF) for degenerative lumbar spondylolisthesis (DLS); nonunion cases have also achieved good clinical outcomes. Facet fusion (FF), a minimally invasive evolution of PLF, also resulted in good clinical outcomes. We aimed to assess the course of nonunion cases after FF and determine whether the nonunion cases achieved good clinical outcomes. We retrospectively reviewed the records of 136 patients who underwent FF for DLS. Range of motion (ROM) at the fused level was measured using a flexion-extension lateral radiograph preoperatively and 1 year postoperatively. Patients were classified into the Fusion or Unconfirmed Fusion group by computed tomography (CT) 1 year postoperatively. Furthermore, patients in the Unconfirmed Fusion group were classified into the Delayed Union or Nonunion group depending on the confirmation status of FF upon the following CT. The average preoperative ROM and clinical outcomes were compared between the three groups. The Fusion, Delayed Union, and Nonunion groups had 109, 14, and 13 patients, respectively. In the Nonunion group, the average ROM significantly decreased from 13.0° preoperatively to 4.9° postoperatively. There was a significant difference in the average preoperative ROM between the groups. The larger the preoperative ROM, the fewer facets fused. There was no significant difference in clinical outcomes between the groups. Five patients (3.7%) required revision surgery for adjacent segment disease 1-5.5 years after FF. Even nonunion cases after FF achieved good clinical outcomes, likely because the unstable spondylolisthesis was stabilized. FF did not require revision surgery for nonunion itself.

Pedicle screw shift without loosening following instrumented posterior fusion: limitations of pedicle screw fixation.

The disc angle at the fused segment is extended in operative prone position, but eventually returns to preoperative neutral position within 6 months to 1 year. This study aimed to assess pedicle screw (PS) shift without loosening to identify the mechanism of the change in disc angle after posterior fusion for degenerative lumbar spondylolisthesis (DLS). Sixty-three consecutive patients who underwent facet fusion for L4 single-level DLS were retrospectively reviewed using computed tomography (CT) immediately after surgery and 6 months postoperatively. Twenty-two patients (88 PSs) in whom the disc angle had decreased by more than 4° at 6-month postoperative radiographic follow-up were selected to more readily identify and quantify PS shift. Six patients with PS loosening and/or nonunion were excluded. We reconstructed a CT plane, vertical to the cranial endplate of the vertebrae and passing through the cannula used for percutaneous PSs. Angle α, which is formed by the cranial endplate and the cannula on this plane, was measured. A change in angle α of more than 2° between the immediate postoperative period and the 6-month follow-up was defined as a PS shift. Angle α did not change by more than 2° in any of the 44 PSs in the upper vertebrae of the fused segment. In the lower vertebrae, angle α changed by more than 2° in 22 of 44 PSs. The change in angle α in the lower vertebrae (average, 2.3°) was significantly greater than that in the upper vertebrae (average, 0.2°) (P < 0.0001). The change in the disc angle was not relevant to clinical outcomes assessed by the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire, the Roland-Morris Disability Questionnaire, and the visual analogue scale. The disc angle at the fused segment returned to preoperative neutral position due to PS shift without loosening, mainly in the lower vertebrae. PS shift is caused by bone remodeling in response to biomechanical load, similar to that in orthodontic tooth movement. As PS has limited ability to maintain a lordotic disc angle, even with the insertion of a cage, lumbar alignment will return to preoperative neutral position owing to cage subsidence or adjacent segment disease. These findings might indicate that it is not necessary to correct the spinal alignment for DLS.

Good clinical outcomes and fusion rate of facet fusion with a percutaneous pedicle screw system for degenerative lumbar spondylolisthesis: minimally invasive evolution of posterolateral fusion.

STUDY DESIGN: A retrospective clinical and radiographical study. OBJECTIVE: To assess the clinical outcomes and fusion rate of facet fusion (FF) for degenerative lumbar spondylolisthesis (DLS). SUMMARY OF BACKGROUND DATA: On the basis of the long-term clinical and radiological follow-up studies of posterolateral fusion (PLF)-that is, intertransverse process fusion with pedicle screw instrumentation-for DLS, we recognized that FF alone would be sufficient for spinal fusion. METHODS: Eighty-eight patients who underwent FF for single-level DLS were retrospectively reviewed after at least 1 year of follow-up. The control group comprised 21 patients who underwent conventional PLF. The operative technique involved a 5-cm midline skin incision, bilateral laminar fenestration, and FF with autologous bone harvested from the spinous process. Percutaneous pedicle screws were then inserted through the fascia. The fusion rate of FF was evaluated using computed tomography, and the change in the range of motion at the fused level was assessed on flexion-extension lateral radiographs. The Japanese Orthopaedic Association Back Pain Evaluation Questionnaire was used to assess the therapeutic effectiveness of FF. The results of the Roland-Morris Disability Questionnaire and the visual analogue scales of low back pain, buttock and lower limb pain, and buttock and lower limb numbness were evaluated. RESULTS: The fusion rate was 88.6% (78/88 cases). Among 10 patients with inadequate fusion, the average range of motion significantly decreased from 14.4° preoperatively to 4.3° postoperatively. The Japanese Orthopaedic Association Back Pain Evaluation Questionnaire category scores demonstrated therapeutic effectiveness in 93.0% of the patients for walking ability and in 73.0% of the patients for low back pain. The average preoperative scores of the Roland-Morris Disability Questionnaire and the visual analogue scales of low back pain, buttock and lower limb pain, and buttock and lower limb numbness were significantly reduced postoperatively in the FF group. CONCLUSION: FF achieved good clinical outcomes that were superior to those of conventional PLF with a comparable fusion rate. It is useful for managing DLS and is a minimally invasive evolution of PLF. LEVEL OF EVIDENCE: 3.

Animated respiratory movement of a spinal intradural arachnoid cyst visualized by intraoperative ultrasonography.

This study aims to describe the animated respiratory movement of a spinal intradural arachnoid cyst visualized by intraoperative ultrasonography. A 69-year-old man with a spinal arachnoid cyst of the thoracic spine presented with gait disturbance. Magnetic resonance images showed a mild anterior displacement and flattening of the spinal cord at T4-T5. We performed ultrasonography before incision of the dura during the operation and observed the movement of the cyst consisting of not only pulsation in accordance with the cardiac cycle but also rhythmic expansion and contraction in accordance with the respiratory cycle. In the inspiratory phase, the cyst gradually expanded and pulsated in accordance with the cardiac cycle. In the expiratory phase, the cyst gradually contracted with the same pulsation. After resection of the cyst, the patient's neurological improvements were excellent. To our knowledge, this is the first report of animated respiratory movement of a spinal arachnoid cyst visualized by intraoperative ultrasonography. Although cine magnetic resonance imaging can detect spinal intradural arachnoid cysts preoperatively, intraoperative ultrasonography is useful for close analysis of their movement and pathology. Considering the dynamic compression mechanism revealed in this study, we think that an early operation should be performed for such cysts.

Clinical results of posterior stabilization without decompression for thoracolumbar burst fractures: is decompression necessary?

The purpose of this study is to investigate the clinical outcome of posterior stabilization without decompression for thoracolumbar burst fractures. Thirty-one consecutive cases of thoracolumbar fractures involving T11-L2 stabilized by a pedicle screw system were reviewed. Neither reduction of the height of a fractured body nor any decompression procedure was added during surgery. Twenty-two patients had incomplete paraplegia; one patient had complete paraplegia. Neurological recovery and remodeling of the spinal canal were evaluated. Neurological status was evaluated at the time of injury, just before and after surgery, and at final follow-up. The degree of spinal canal compromise was assessed using axial CT scan images. The duration of follow-up averaged 39.6 months. The mean spinal canal compromise at the time of injury was 41.6%, and no significant correlation was observed between the degree of canal compromise and the severity of the neurological deficit. Within 2-3 weeks, spinal canal remodeling had started in all patients whose spinal canal compromise was more than 30%, and canal compromise had decreased significantly 3-4 weeks after injury. Seventeen of 22 patients with incomplete paraplegia had already shown partial neurological recovery even before surgery. At the final follow-up, all patients with incomplete paraplegia had improved by at least one modified Frankel grade. This study suggests that the effect of decompressing thoracolumbar fractures with neurological deficits remains unclear and questions the need to operate simply to remove retropulsed bone fragments. Posterior stabilization without decompression should constitute appropriate surgical treatment for these fractures.

Occipitocervical fusion has potential to improve sleep apnea in patients with rheumatoid arthritis and upper cervical lesions.

STUDY DESIGN: Case series. OBJECTIVE: To analyze factors that contribute to the development of sleep apnea in patients with rheumatoid arthritis (RA) and upper cervical lesions. SUMMARY OF BACKGROUND DATA: No large prospective study has analyzed the association between sleep apnea and upper cervical involvement resulting from RA. Furthermore, only 1 report in the literature describes a case of sleep apnea accompanying rheumatoid vertical subluxation of the odontoid process. METHODS: The authors analyzed 8 consecutive RA patients with upper cervical lesions who underwent occipitocervical (O-C) fusion. The patients were examined with all-night polysomnography before and after surgery. Patients with apnea-hypopnea index values>or=5 were diagnosed to have sleep apnea. O-C2 angles were calculated from cervical radiographs. RESULTS: All 8 patients were diagnosed as having sleep apnea, and most of their apneic episodes were obstructive in origin. Among the 4 patients with medullary compression, central apneic episodes comprised

Posterior instrumented fusion without neural decompression for incomplete neurological deficits following vertebral collapse in the osteoporotic thoracolumbar spine.

Previous reports have emphasized the importance of neural decompression through either an anterior or posterior approach when reconstruction surgery is performed for neurological deficits following vertebral collapse in the osteoporotic thoracolumbar spine. However, the contribution of these decompression procedures to neurological recovery has not been fully established. In the present study, we investigated 14 consecutive patients who had incomplete neurological deficits following vertebral collapse in the osteoporotic thoracolumbar spine and underwent posterior instrumented fusion without neural decompression. They were radiographically and neurologically assessed during an average follow-up period of 25 months. The mean local kyphosis angle was 14.6 degrees at flexion and 4.1 degrees at extension preoperatively, indicating marked instability at the collapsed vertebrae. The mean spinal canal occupation by bone fragments was 21%. After surgery, solid bony fusion was obtained in all patients. The mean local kyphosis angle became 5.8 degrees immediately after surgery and 9.9 degrees at the final follow-up. There was no implant dislodgement, and no additional surgery was required. In all patients, back pain was relieved, and neurological improvement was obtained by at least one modified Frankel grade. The present series demonstrate that the posterior instrumented fusion without neural decompression for incomplete neurological deficits following vertebral collapse in the osteoporotic thoracolumbar spine can provide neurological improvement and relief of back pain without major complications. We suggest that neural decompression is not essential for the treatment of neurological impairment due to osteoporotic vertebral collapse with dynamic mobility.

Intradural extramedullary tuberculoma of the thoracic spine: paradoxical response to antituberculous therapy.

Intradural extramedullary tuberculoma of the spinal cord (IETSC) is a rare complication of tuberculosis, which can occur as a paradoxical response to antituberculous therapy. A 46-year-old woman with tuberculosis meningitis developed an acute sensory disturbance and paraplegia eight weeks after the antituberculous treatment was started. MRI revealed a cystic lesion at the Th 2 and 3 vertebrae levels, and continuous dural thickening. Laminectomy was performed; soft granulomas were unexpectedly observed inside the dura matter. After the operation, the patient experienced progressive improvement in motor strength. IETSC should be known as rare but possible complication of tuberculous meningitis.

[A case of parkinsonian syndrome caused by normal pressure hydrocephalus accompanied by the cauda equina neurinoma].

A case of parkinsonian syndrome caused by normal pressure hydrocephalus (NPH) accompanied by cauda equina neurinoma is reported. A 69-year-old woman presented with typical symptoms of parkinsonism, including akinesia, resting and postual tremor, and cog-wheel rigidity. CT scan of the brain revealed dilatation of ventricles, but she did not present dementia and urinary incontinence that are common symptoms in NPH. Her cerebrospinal fluid (CSF) pressure was normal, and her protein level was high at 2,970 mg/dl. An electroencephalogram (EEG) showed diffuse slow waves. An IMP-SPECT images of the brain showed diffuse reduction of radioisotope uptake. Levodopa was not effective in treating her parkinsonism. Removal of the tumor caused dramatic improvement in her parkinsonism. Her CSF protein level was normalized and EEG and SPECT images were improved after the operation. However, ventricular size on brain CT showed no change. It was considered that the causal mechanism of NPH was due to high protein levels in the CSF. The parkinsonism in this case was caused by dysfunction of the circuits linking the cortex, basal ganglia, and thalamus associated with metabolic disorder due to periventricular ischemia. Typical parkinsonism caused by NPH associated with spinal cord tumor has not been reported. When we examine a patient with parkinsonian syndrome caused by NPH, we should check the CSF protein level. And if that level is high, the possibility of spinal cord tumor should be considered.