Faculty Bibliography

In the pediatric population, clear cell meningiomas are more frequently intracranial than intraspinal in location. Tumors recur in up to 40% of cases within 15 postoperative months and are often managed with repeated resection with or without radiation therapy. The management strategy for adults with clear cell meningiomas involving the lumbar spinal canal (cauda equina) is less clearly defined. A 41-year-old woman presented with mild, right greater than left, lower extremity paresis. An enhanced magnetic resonance (MR) scan revealed a homogeneously enhancing intradural lesion filling the spinal canal at the L3-L4 level. Preoperative noncontrast MR studies of the brain and cervical and thoracic spine were negative. An L2-L5 laminectomy was performed for gross total excision of the intradural lesion, which was adherent to one nerve root of the cauda equina. Frozen-section diagnosis confirmed clear cell tumor. Differential diagnoses included meningioma versus renal cell carcinoma. Negative postoperative chest, abdominal, and pelvic computed tomography studies ruled out tumor of renal cell origin. Enhanced MR studies of the neuraxis proved negative. Consultations with multiple oncologists and radiation therapists recommended neither radiation nor chemotherapy following this initial surgery. She remains disease-free 1 year postoperatively. The high recurrence rate for clear cell meningiomas in children requires repeated tumor resection with or without secondary radiation therapy. Following gross total resection of lumbar tumors in adults, reserving radiation therapy for secondary recurrences provides optimal management.

STUDY DESIGN: To determine the osteogenicity of posterior longitudinal ligament ossification, the posterior longitudinal ligament obtained during anterior cervical surgery from patients with the disorder was analyzed with in vitro cultures. OBJECTIVES: To determine the osteogenicity of the posterior longitudinal ligament. SUMMARY OF BACKGROUND DATA: The osteogenicity of posterior longitudinal ligament ossification in North America requires better documentation. METHODS: The posterior longitudinal ligament obtained during anterior cervical corpectomy with fusion from seven patients, three with ossification of the posterior longitudinal ligament documented by magnetic resonance imaging and computed tomography and four with spondylosis, was blindly submitted for in vitro culture. Explants of the posterior longitudinal ligament were placed in Dulbecco modified Eagle medium with 10% fetal calf serum, antibiotics, 4 mmol/L x L-proline, and 50 mg/L ascorbic acid. After reaching confluency, cells were trypsinized, and first-passage cells were used for all osteocalcin measurements to establish their osteoblastic phenotype. Periosteal cells, previously shown to synthesize osteocalcin, were used as a positive control. The cells were incubated with 1,25(OH)2 vitamin D3 at 10E-8 M for 72 hours in serum-free medium. The supernatants were collected and frozen, after which the quantity of osteocalcin induced by exposure to 1,25(OH)2 vitamin D3 was determined using enzyme-linked immunoassay. Control replicate cultures were measured without incubation using vitamin D3. RESULTS: Ossification of the posterior longitudinal ligament cell lines responded positively with osteocalcin synthesis in the 0.1 to 0.4 ng/M range. The cell line of the patient with spondylosis alone did not respond to vitamin D3 priming. CONCLUSIONS: Posterior longitudinal ligament cells from the three North American white patients with ossification of the posterior longitudinal ligament, when cultured in vitro, synthesized osteocalcin on vitamin D3 priming, confirming their osteoblastic phenotype, whereas posterior longitudinal ligament cells from four white patients with isolated spondylosis did not.

STUDY DESIGN: To establish the diagnosis of dural penetration on preoperative computed tomographic studies of the cervical spine in patients with ossification of the posterior longitudinal ligament (OPLL). OBJECTIVES: To define before surgery the pathognomonic computed tomographic findings of OPLL extending to and through the dura. SUMMARY OF BACKGROUND DATA: On preoperative computed tomographic studies, Hida et al have described the single-layer sign characterized by a solid mass of hyperdense OPLL and the double-layer sign defined by two (anterior and posterior) ossified rims surrounding a central nonossified but hypertrophied posterior longitudinal ligament. Only 1 of the 9 patients exhibiting the single-layer sign but 10 of 12 patients showing the double-layer sign had no separate dural plane identified at surgery. METHODS: Only 2 of 54 patients undergoing multilevel cervical circumferential OPLL procedures had absent dura at surgery. Computed tomographic examinations for all patients were retrospectively reviewed to determine unique signs of dural penetration. RESULTS: Dura was absent in 1 of 12 patients who had the single-layer CT sign that was additionally characterized by an irregular C angular configuration. Only 1 of 4 patients exhibiting the double-layer computed tomographic sign had absent dura at surgery. The remaining 38 patients had the smooth-layer sign, characterized by more regular margins of classic (22 patients) or early OPLL (16 patients). CONCLUSIONS: The double-layer computed tomographic sign is more pathognomonic for dural penetration than the single-layer sign. The smooth-layer sign, indicating a clean dural plane, is more typical in North American patients

Cervical laminectomy with posterior wiring and fusion is valuable for the management of cervical ossification of the posterior longitudinal ligament (OPLL), spondylosis, ossification of the yellow ligament (OYL), stenosis, and instability. Within 1.5 years, five patients averaging 73 years of age developed severe myelopathy. Dynamic radiographs confirmed an intact cervical lordosis with active subluxation and instability at one or two levels, whereas magnetic resonance and computed tomography scans showed OPLL, spondylosis, OYL, and stenosis. After multilevel laminectomy with posterior wiring and fusion and immobilization in cervicothoracic orthoses, patients fused in an average of 3.6 months. All patients improved, showing mild to moderate residual postoperative myelopathy an average of 13 months later (range, 6-19 months). With an intact cervical lordosis, laminectomy with posterior wiring and fusion was used successfully to manage five patients with OPLL, spondylosis, OYL, stenosis, and instability

The authors evaluated the clinical, radiological, and surgical management of ossification of the anterior longitudinal ligament (OALL) that contributed to dysphagia in a patient with simultaneous cervical ossification of the posterior longitudinal ligament (OPLL). A 57-year-old man presented with increasing dysphagia and moderate myelopathy. Imaging studies, including esophagoscopy, revealed marked esophageal compression due to OALL that extended between the C2-5 levels and significant C5-7 OPLL that compressed the distal cervical spinal cord. The use of rongeurs and a high-speed drill facilitated excision of the C2-5 OALL mass, and a routine anterior corpectomy with fusion was performed at the C5-7 level. Postoperatively, the patient's dysphagia and symptoms of myelopathy immediately resolved. The strut graft became fully fused 3 months postoperatively, as demonstrated on dynamic x-ray films, and the patient has remained asymptomatic 4 months postoperatively. Patients with dysphagia and coexisting myelopathy benefit from simultaneous surgery for resection of OALL and OPLL masses

Can simultaneous anterior and posterior (circumferential) surgery in patients with cervical ossification of the posterior longitudinal ligament (OPLL)/stenosis, achieving both decompression and stabilization, be accomplished with acceptable risk? Between 1989 and 1996, 22 circumferential procedures were performed, including an average 2.5-level anterior corpectomy with 5-level posterior wiring and fusion. These patients were severely myelopathic (average Nurick grade 3.5) and were followed for a mean interval of 22 months (range 4-52 months). Circumferential procedures required an average of 9.8 h and 3.5 U of blood transfused. Postoperatively, patients improved approximately +3.0 Nurick grades. Simultaneous circumferential surgery for OPLL/stenosis may be successfully performed in <10 h with limited blood loss.

In the cervical spine, routine and contrast magnetic resonance (MR)- and computed tomography (CT)-based studies may fail to differentiate between an ectatic vertebral artery and a solid foraminal mass. A complete cervical and lumbar Myelo-CT scan in a 67-year-old female with lumbar stenosis revealed an incidental, left-sided C3-C4 foraminal mass. A vascular lesion was suspected when the MR study revealed the lesion to be a signal void. MR angiography confirmed an ectatic C3-C4 vertebral artery loop. The possibility of a vertebral artery anomaly should be considered in patients with asymptomatic lateral and foraminal cervical lesions on CT studies. In these patients, routine MR and MR angiography are necessary to demonstrate the status of the vertebral artery in the foramen.

The clinical, neuroradiological, and surgical management of three cases of intradural disc herniations--one each in the cervical, thoracic, and lumbar regions--are presented. Intradural disc herniations comprise only 0.27% of all herniated discs. Three percent occur in the cervical, 5% in the thoracic, and 92% in the lumbar spinal canal. Those with cervical or thoracic lesions frequently exhibit profound myelopathy, whereas those with lumbar lesions demonstrate radicular or cauda equina syndromes. Although varying combinations of the MRI, non-contrast CT, myelogram, and myelo-CT scans may at times fail to accurately establish the diagnosis of an intradural disc herniation prior to surgery, the index of suspicion raised by the lack of clinical correlation with surgical findings justifies an intradural exploration.

Two patients with pain referable to the low back and sacroiliac regions had bone scans with similar findings. In each, one sacroiliac joint was "warm" (uptake on that side was slightly greater than that in the contralateral area). Ga-67 imaging also demonstrated increased uptake in the same locale. Subsequent CT scanning revealed pelvic abscesses adjacent to the affected joints. Asymmetric uptake of bone imaging agent may have been related to hyperemia and "heating" of the sacroiliac joint. Rapid defervescence with antibiotics and drainage (and no CT evidence of bone involvement) suggested that osteomyelitis was not involved in these cases.

The management of 60 patients with far lateral lumbar disc herniations operated on over a 5-year period are presented. These lesions were located superiorly within the neural foramens beneath or distal to the facet joints. The type of surgery performed in 43 of 60 (72%) of these patients was significantly altered by the presence of diffuse and lateral recess stenosis. This was better appreciated on the myelogram and myelo-CT (M-CT) studies than with the noncontrast CT and MRI examinations alone. Myelo-CT findings were particularly valuable in assessing patients who had previous surgical procedures