Can Conventional Magnetic Resonance Imaging Substitute Three-Dimensional Magnetic Resonance Imaging in the Diagnosis of Lumbar Foraminal Stenosis?

Methods@#We investigated 154 foramina at L5–S1 in 77 patients. All the patients had degenerative lumbar disorders and had undergone both conventional MRI and 3D-MRI during the same visit. Differences between the FSRs calculated from conventional and 3D-MRI reconstructions and any correlations with the plain radiography findings were assessed. @*Results@#In foramina that had a FSR of <50% on conventional MRI, the difference between the FSR obtained using conventional MRI and 3D-MRI was 5.1%, with a correlation coefficient of 0.777. For foramina with a FSR ≥50% on conventional MRI, the difference was 20.2%, with a correlation coefficient of 0.54. FSR obtained using 3D-MRI was significantly greater in patients who required surgery than in those who were successfully treated with conservative methods (88% and 42%, respectively). Segments with spondylolisthesis or lateral wedging showed higher FSRs than those without these conditions on both types of MRI. @*Conclusions@#FSRs <50% obtained using conventional MRI were sufficiently reliable; however, the results were inaccurate for FSRs ≥50%. Patients with high FSRs on 3D-MRI were more likely to require surgical treatment. Therefore, 3D-MRI is recommended in patients with suspected stenosis detected using conventional MRI or plain radiographs.

Can Conventional Magnetic Resonance Imaging Substitute Three-Dimensional Magnetic Resonance Imaging in the Diagnosis of Lumbar Foraminal Stenosis?

Methods@#We investigated 154 foramina at L5–S1 in 77 patients. All the patients had degenerative lumbar disorders and had undergone both conventional MRI and 3D-MRI during the same visit. Differences between the FSRs calculated from conventional and 3D-MRI reconstructions and any correlations with the plain radiography findings were assessed. @*Results@#In foramina that had a FSR of <50% on conventional MRI, the difference between the FSR obtained using conventional MRI and 3D-MRI was 5.1%, with a correlation coefficient of 0.777. For foramina with a FSR ≥50% on conventional MRI, the difference was 20.2%, with a correlation coefficient of 0.54. FSR obtained using 3D-MRI was significantly greater in patients who required surgery than in those who were successfully treated with conservative methods (88% and 42%, respectively). Segments with spondylolisthesis or lateral wedging showed higher FSRs than those without these conditions on both types of MRI. @*Conclusions@#FSRs <50% obtained using conventional MRI were sufficiently reliable; however, the results were inaccurate for FSRs ≥50%. Patients with high FSRs on 3D-MRI were more likely to require surgical treatment. Therefore, 3D-MRI is recommended in patients with suspected stenosis detected using conventional MRI or plain radiographs.

Autogenic Rib Graft for Atlantoaxial and Occipitocervical Fixation in Pediatric Patients

STUDY DESIGN: Retrospective case series. PURPOSE: To evaluate surgical outcomes and effectiveness of an autogenic rib graft for upper cervical fixation in pediatric patients. OVERVIEW OF LITERATURE: Autogenic bone grafts have long been considered the ‘gold standard’ bone source for posterior cervical fusion in pediatric patients. However, there are some unsolved problems associated with donor-site morbidity and amount of bone grafting. METHODS: We studied five consecutive pediatric patients who underwent atlantoaxial fixation or occipitocervical fixation (OCF) using an autogenic rib graft with at least 2 years of follow-up (mean age, 9.8 years; mean follow-up period, 73.0 months). Two patients underwent OCF without screw-rod constructs and three patients with screw-rod constructs. Autogenic rib grafts were used in all patients. We evaluated the surgical outcomes including radiographic parameter, bony union, and perioperative complications. RESULTS: The atlantoaxial interval (ADI) was corrected from 11.6 to 6.0 mm, and the C1–2 angle was corrected −14.8° to 7.8°. The C2–7 angle was reduced from 31° to 9° spontaneously. Two patients with OCF required revision surgery due to loss of correction. Patients did not experience any complication associated with the donor sites (rib bone grafts). Six months postoperation X-rays clearly showed regeneration of the rib at the donor sites. Bony fusion was achieved in all patients; however, bony fusion occurred more slowly in patients without screw-rod constructs compared with patients with screw-rod constructs. Bone regeneration of the rib was observed in all patients with no complications at the donor site. CONCLUSIONS: Autogenic rib grafts have advantages of potential bone regeneration, high fusion rate, and low donor-site morbidity. In addition, a screw-rod construct provides better bony fusion in pediatric patients with OCF and atlantoaxial fixation.

Clinical and Radiological Outcomes after Microscopic Bilateral Decompression via a Unilateral Approach for Degenerative Lumbar Disease: Minimum 5-Year Follow-Up

STUDY DESIGN: A retrospective study. PURPOSE: To assess postoperative bone regrowth at surgical sites after lumbar decompression with >5 years of follow-up. Postoperative preservation of facet joints and segmental spinal instability following surgery were also evaluated. OVERVIEW OF LITERATURE: Previous reports have documented bone regrowth after conventional laminectomy or laminotomy and several factors associated with new bone formation. METHODS: Forty-nine patients who underwent microscopic bilateral decompression via a unilateral approach at L4–5 were reviewed. Primary outcomes included correlations among postoperative bone regrowth, preservation of facet joints, radiographic parameters, and clinical outcomes. Secondary outcomes included comparative analyses of radiographic parameters and clinical outcomes among preoperative diagnoses (lumbar spinal stenosis, degenerative spondylolisthesis, and degenerative lumbar scoliosis). RESULTS: The average value of bone regrowth at the latest follow-up was significantly higher on the dorsal side of the facet joint (3.4 mm) than on the ventral side (1.3 mm). Percent facet joint preservation was significantly smaller on the approach side (79.2%) than on the contralateral side (95.2%). Bone regrowth showed a significant inverse correlation with age, but no significant correlation was observed with facet joint preservation, gender, postoperative segmental spinal motion, or clinical outcomes. Subanalysis of these data revealed that bone regrowth at the latest follow-up was significantly greater in patients with degenerative lumbar scoliosis than in those with lumbar spinal stenosis. Postoperative segmental spinal motion at L4–L5 did not progress significantly in patients with degenerative spondylolisthesis or degenerative lumbar scoliosis compared with those with lumbar spinal stenosis. CONCLUSIONS: Microscopic bilateral decompression via a unilateral approach prevents postoperative spinal instability because of satisfactory preservation of facet joints, which may be the primary reason for inadequate bone regrowth. Postoperative bone regrowth was not related to clinical outcomes and postoperative segmental spinal instability.

Prevalence of Diffuse Idiopathic Skeletal Hyperostosis in Patients with Spinal Disorders

STUDY DESIGN: Retrospective cohort study. PURPOSE: The purpose of this study was to evaluate the prevalence of diffuse idiopathic skeletal hyperostosis (DISH) in patients with spinal diseases determined by roentgen images of the whole spine. OVERVIEW OF LITERATURE: Although several studies have investigated the prevalence of DISH in healthy subjects, no detailed data have been reported on the prevalence of DISH in patients with degenerative spinal disorders. METHODS: Standing whole-spine roentgen images of 345 consecutive patients who underwent surgery in our hospital were obtained. Patients aged <18 years or with congenital spinal disease, metastatic spinal tumors, or inflammatory spinal disease were excluded. In total, 281 patients were eligible for inclusion. The presence of DISH was assessed according to Resnick's criteria and Mata's scoring system. The prevalence, location, and numbers of fused vertebral bodies of DISH were recorded. RESULTS: DISH was present in 25.6% of patients (72/281). The prevalence of DISH in the 41–49, 50–59, 60–69, 70–79, and ≥80 year age groups was 8.3% (2/24), 9.8% (5/51), 16.0% (12/75), 49.5% (48/97), and 33.3% (4/12), respectively; the prevalence increased with age. The average number of fused vertebral bodies was 7.5. More than 80% of DISH was located from T7 to T11, and more than 95% of DISH was located at T9/10. Patients with DISH were significantly older (71.1 years vs. 60.9 years, p<0.05), and men were more likely to have DISH than women (p<0.05). CONCLUSIONS: In patients with degenerative spinal diseases with DISH, fused vertebrae were found most frequently in the lower thoracic spine, and their prevalence increased with age. DISH may be an age-related skeletal disorder with a higher overall prevalence in patients with spinal disorders than that in healthy subjects.

Utility of Discography as a Preoperative Diagnostic Tool for Intradural Lumbar Disc Herniation

Preoperative definitive diagnosis of intradural lumbar disc herniation (ILDH) is difficult despite the availability of various neuroradiological investigative tools. We present a case of ILDH diagnosed preoperatively by discography and computed tomography-discography (disco-CT).The patient was a 63-year-old man with acute excruciating right leg pain. Discography and disco-CT demonstrated leakage of the contrast medium into the intradural space. Based on these findings, a right L5 nerve root disturbance caused by ILDH was diagnosed. A right L5 hemi-laminectomy and a dorsal durotomy were performed. The herniated disc was carefully dissected and then completely removed. Three months after surgery, the patient had fully recovered. This report highlights the importance of making a definitive diagnosis of ILDH preoperatively for better surgical planning and improved clinical outcomes. Furthermore, discography and disco-CT are both useful preoperative diagnostic tools for the diagnosis of ILDH.