Use of spinous processes to determine the optimal trajectory for placement of lateral mass screws: technical note.

STUDY DESIGN: Retrospective chart analysis. OBJECTIVE: In the current report, we present a new technique for the placement of lateral mass screws from C3 to C7. The safety, complications, and long-term clinical and imaging follow-up were analyzed. To address potential risk factors for this technique, relevant literature was reviewed and discussed herein. SUMMARY OF BACKGROUND DATA: Multiple techniques have been reported to place lateral mass screws in the subaxial cervical spine. The trajectory used aims to avoid the vertebral artery and the exiting nerve root. Because of inherent differences in determining the screw trajectory for placement, there can be considerable differences among surgeons. METHODS: A retrospective analysis of our experience over the period from 2003 to 2006 was undertaken. Standard practices for obtaining institutional review board approval were followed. Radiographs, hospital records, and office charts of 34 patients were reviewed. There was an equal distribution between males and females and the mean age was 56.3 years. Pain was the most frequent presentation. The indications for posterior instrumentation included instability secondary to pseudoarthrosis, infection, spondylosis, osseous metastasis, trauma, and iatrogenic etiologies. RESULTS: The follow-up period ranged from 1 to 30 months (average 9.1 mo). Postoperative complications included wound infection (3 cases), malpositioned screw (1 case), cerebrospinal fluid leak (1 case), and dislodged rod (1 case). There were no mortalities directly related to the procedure. CONCLUSIONS: This technique for placement of lateral mass screws yielded adequate fixation without any appreciable neurovascular complications. It provides a useful alternative for screw placement in patients with intact spinous processes.

Delayed lateral rectus palsy following resection of a pineal cyst in sitting position: direct or indirect compressive phenomenon?

A rare case of delayed lateral rectus palsy in a patient following resection of a pineal lesion in the sitting position is presented. Postoperative pneumocephalus is common following craniospinal surgical intervention in the sitting position. The sixth cranial nerve is frequently injured because of its prolonged intracranial course. A 13-year-old girl was evaluated for unremitting headaches. No focal deficits were demonstrated on neurological examination. Magnetic resonance imaging revealed a cystlike pineal region mass with peripheral enhancement following intravenous contrast administration. A supracerebellar infratentorial craniotomy was performed in the sitting position, and complete resection of the lesion was achieved. Her postoperative course was complicated by sixth nerve palsy on the third postoperative day. Her symptoms improved with conservative management. The occurrence of sixth cranial nerve palsy secondary to pneumocephalus is a rare entity. Even rarer is the report of this anomaly following craniotomy in the sitting position. This patient's symptoms manifested in a delayed fashion. Although uncommon, this complication should be considered in patients undergoing cranial or spinal surgical interventions in this position.

Reactivation of dormant lumbar methicillin-resistant Staphylococcus aureus osteomyelitis after 12 years.

The adequate treatment of methicillin-resistant Staphylococcus aureus (MRSA) osteomyelitis has intrigued clinicians for some time. As the resistance of these pathogens, coupled with the increase in community-acquired cases, continues steadily to rise, clinicians are finding it useful to employ multi-modal approaches for efficacious treatment. The authors present a single case report of a patient with recurrent MRSA osteomyelitis, lumbar paraspinal and epidural abscess. He was found to have decreased muscle strength and was hyporeflexic in the involved extremity. Serum testing demonstrated MRSA bacteremia. Neuroimaging studies revealed evidence of paraspinal abscess and a presumed herniated nucleus pulposus at the L5/S1 interspace with significant nerve root compromise. Despite antimicrobials, his symptoms persisted, necessitating surgical exploration. At surgery, paraspinal and epidural abscesses were encountered and debrided; however, no herniated disc was visualized. This case demonstrates the diagnostic and therapeutic dilemmas with which these lesions present. We postulate that the MRSA osteomyelitis/discitis pathogens were walled off in the disc space and subsequently inoculated the soft tissues with ensuing bacteremia. We concur that antimicrobial treatment should be the first line of therapy for these patients; however, surgical debridements and cautious spinal instrumentation should be employed where appropriate.

Nonhemorrhagic cord contusion after percutaneous fiducial placement: case report and surgical recommendations.

STUDY DESIGN: Single case report and extensive literature review. OBJECTIVES: To present the first such report of cervical cord contusion after the percutaneous placement of gold-seed fiducials. The pathomechanics and surgical recommendations are reviewed. BACKGROUND: Spinal cord injuries are well documented in the medical literature. These injuries range from cord contusion to transection and result primarily from trauma. A single case report of a patient who was found to have a nonhemorrhagic cervical spinal cord contusion after percutaneous fiducial implantation is presented. METHODS: Single case report. RESULTS: The patient underwent percutaneous placement of fiducials for stereotactic radiosurgery for a nerve sheath tumor. Postoperatively she had primarily sensory complaints; no motor deficits were detected on neurological examination. Neuroimaging studies demonstrated nonhemorrhagic cervical cord contusion. She was treated conservatively and had complete resolution of her symptoms. CONCLUSIONS: The likely mechanism for the contusion was neck hyperextension during thrusting maneuvers during fiducial implantation. This is yet another report of normal intraoperative-evoked potentials with postoperative neurological sequelae. A dedicated team approach involving ancillary staff, anesthesiologists, and surgeons should be utilized to avert this potentially devastating complication.

Cranial base approaches for the surgical treatment of aggressive posterior fossa dural arteriovenous fistulae with leptomeningeal drainage: report of four technical cases.

OBJECTIVE AND IMPORTANCE: Dural arteriovenous fistulae (DAVFs) with leptomeningeal drainage have an aggressive natural history. Urgent treatment is necessary to arrest neurological deterioration and to prevent the risk of intracranial hemorrhage. In many patients, a primary endovascular approach is the most appropriate and most successful treatment available. In some circumstances, however, surgical intervention is required for complete obliteration. Posterior fossa DAVFs are generally deep-seated and difficult to gain access to with standard surgical approaches. The advent of cranial base surgery allows 360-degree access to the draining venous complex or sinus via extradural bone removal. CLINICAL PRESENTATION: Four patients with posterior fossa DAVFs presented to the neurosurgical service at our institutions. One DAVF was located at the craniocervical junction, and three were tentorial DAVFs of the superior petrosal sinus. All four patients were treated surgically with extradural bone removal. INTERVENTION: Postoperative angiography documented complete obliteration of all four DAVFs. All patients had normal recoveries, with the exception of one patient who experienced persistent temporal lobe seizure activity as a result of the presenting hematoma. One patient died of unrelated causes 2 years after surgery. One postoperative temporal lobe hematoma required evacuation. CONCLUSION: Recent advances in cranial base techniques have allowed the successful obliteration of aggressive posterior fossa DAVFs with acceptable morbidity. The use of these techniques should be considered in selected patients who cannot be treated with endovascular approaches.

Major venous sinus resection in the surgical treatment of recurrent aggressive dural based tumors.

BACKGROUND: Despite gross total resection, aggressive dural based tumors invading major venous sinuses have high recurrence rates with poor long-term survivability. Options for aggressive surgical management of dural sinus invasion may be limited by the inherently high risk of morbidity and mortality. METHODS: Between July 1996 and July 2002, 5 cases of recurrent aggressive dural based tumors were operated on. Gross total resection had been previously performed in 4 cases, and near total resection in 1 case. Tumor pathology included 2 malignant meningiomas, 1 hemangiopericytoma, 1 atypical meningioma, and 1 benign meningioma with atypical features. All tumors recurred within 3 to 47 months and occluded a major venous sinus (four superior sagittal and one dominant right transverse sinus). Gross total resection of tumor and involved venous sinus was accomplished in each case. RESULTS: Three patients had no signs of clinical or radiographic recurrence at 10, 18, and 53 months of follow up. One patient who developed a fatal pulmonary embolism 10 months postoperatively had evidence of tumor progression on autopsy. One patient had tumor recurrence at 10 months, but is alive at 38 months and receiving adjunctive therapy. CONCLUSION: For aggressive dural based tumors that recur with invasion of a major venous sinus, radical resection of tumor and occluded sinus can be performed safely and may improve long-term survival.

The treatment of complex dural arteriovenous fistulae through cranial base techniques.

INTRODUCTION: The endovascular modality of treatment is the preferred treatment modality for DAVF. In some circumstances, successful obliteration may not be possible by endovascular means, and such cases may require a direct surgical treatment. The authors report on their experience with the use of cranial base approaches in the treatment of deep and complex DAVF. MATERIALS AND METHODS: Nine patients were treated between 1992 and 2003. There were six females and three males. Four patients presented with intracerebral hemorrhage, two with progressive myelopathy, two with tinnitus, and one with incapacitating chronic seizures. Four DAVF were tentorial, two transverse sigmoid, one craniocervical, one straight sinus, and one sphenoparietal. Endovascular embolization was attempted and unsuccessful in four cases, and was successful only as an adjunct to surgery in four others. All patients required the use of cranial base approaches to disconnect the fistula or resect the nidus. RESULTS: Complete obliteration of the fistula was possible in all cases. Six-month follow-up results were obtained on seven patients where there was no evidence of recurrence. One postoperative temporal-lobe hematoma required surgical evacuation. One patient died two years postoperatively from an unrelated cause. CONCLUSION: This retrospective study demonstrates that complex DAVF can be successfully treated with the assistance of cranial base techniques.

Technique for collection of cerebrospinal fluid from the cisterna magna in rat.

Cerebrospinal fluid (CSF) is in direct contact with the extracellular space in the central nervous system (CNS), and biological changes in the brain can be reflected in CSF. In the present article, a procedure for collection of CSF in rats is described. The technique quickly and reliably yields large quantities of CSF (50-150 microl) in rats. More importantly, blood contamination of the CSF is avoided. Furthermore, detections of ATP and interleukin (IL)-1 beta in the CSF have been carried out. ATP concentration in the CSF samples was between 8.3 and 15.8 nM, with an average of 10.5+/-0.83 nM (mean+/-SEM). The concentrations of IL-1beta were below the detection limit in the CSF in the laminectomy control rats, but it increased to 0.26+/-0.07 ng/ml at 1h after spinal cord injury. This technique offers an alternative method to surgical cannulation for the collection of CSF in rats.

Intradural extramedullary mature cystic teratoma: not only a childhood disease.

OBJECTIVE: The authors report on the first case of a spinal intradural extramedullary cystic teratoma in an aged patient. These lesions have been reported in adolescents and young adults often with a history of spinal dysraphism. They are believed to be congenital lesions; however, they have also been reported in patients with a history of posterior spinal surgery or lumbar puncture. METHOD: An 85-year-old man was evaluated for persistent and progressive lower extremity paresis. His symptoms began after relatively minor trauma. He had no prior lumbar surgeries. Neuroimaging studies revealed an L1-L2 intradural mass. A putative diagnosis of a cystic intradural extramedullary mass was made. A lumbar laminectomy and durotomy were performed. RESULTS: A cystic lesion containing hair follicles, cartilage, adipose, and neural tissue was encountered. Pathologic review corroborated the diagnosis of cystic teratoma. CONCLUSIONS: The occurrence of cystic teratomas in the absence of previous surgery or lumbar puncture is uncommon. Even rarer are reports of these lesions in aged patients. Of particular interest in this case is the fact that this patient had not undergone any previous lumbar procedures nor did he have a history of spinal dysraphism. Though rare, this entity should be included in the differential of cystic intradural spinal cord lesions.

Does anterior plating maintain cervical lordosis versus conventional fusion techniques? A retrospective analysis of patients receiving single-level fusions.

A retrospective review of medical records and radiographs of patients receiving anterior cervical discectomy and fusion (ACDF) without anterior plating and with anterior plating was performed. The objective of the study was to determine whether a difference exists in cervical lordotic alignment between subjects undergoing single-level ACDF with and without anterior cervical plating instrumentation for symptomatic cervical disc disease. Collapse or settling of grafted bone into the vertebral endplates with resulting kyphotic deformity of the cervical spine is a commonly described complication of anterior discectomy and fusion. Despite the increasing use of instrumentation for the treatment of cervical spine injuries and degenerative conditions, little is known regarding lordotic alignment of the cervical spine in patients who receive plating instrumentation compared with conventional fusion without plating. Accumulating evidence suggests that plating is superior to non-plating techniques in patients with multiple level cervical disc lesions in regard to fusion, return to work rates, and complication rates; however, little is known about maintenance of lordotic curve alignment in single- and multiple-level procedures. Neutral lateral cervical radiographs of 57 patients who underwent single-level ACDF between 1994 and 1999 with anterior screw plates (n = 26), and conventional single-level fusion without anterior screw plates (n = 21) were retrospectively assessed. Measurements were made on weight-bearing lateral cervical radiographs to assess overall sagittal spinal alignment and intersegmental sagittal alignment at the surgical site before surgery, immediately after surgery, 4 to 12 weeks after surgery, and 12+ months after surgery. The average magnitude of overall lordosis measured between C2 and C7 decreased 4.2 degrees in the non-plated group, while being preserved in the plated group. This finding did not reach statistical significance in the long-term follow-up. At the surgical site, the segmental contribution to lordosis decreased an average 2.5 degrees in the non-plated group versus an increase of 5.67 degrees in the plated group, and this finding was statistically significant between groups measured at all pre- and postoperative visits (p < 0.01). On average, the plating procedure resulted in preserving overall lordosis while increasing the magnitude of segmental lordosis at the surgical site. In comparison, the conventional method resulted in a net loss of overall lordosis and segmental lordosis at the surgical site.