Technical strategies and anatomic considerations for parapedicular access to thoracic and lumbar vertebral bodies.

OBJECTIVES: To investigate and illustrate a variation on the traditional percutaneous access to the vertebral body via a parapedicular approach. DESIGN: An effective parapedicular access technique that could safely and reliably guide the needle tip into the center of the vertebral body was developed from cadaver dissection observations for the purpose of clinical use. PATIENTS: A total of 102 vertebral compression fractures from T-4 to L-5 were treated via the parapedicular access at our institution between July 2005 and March 2006. There were 72 patients between the ages of 17 and 96 years (mean age: 68.2 years) who underwent treatment. RESULTS: The cadaver dissection revealed a relatively avascular and aneural portion of the vertebral body along the superior margin of the vertebral body-pedicle junction. A total 102 vertebral fractures were treated using the parapedicular access technique without any recognized clinical complications from the needle access or the instrumentation. CONCLUSIONS: The thoracic and lumbar vertebral bodies may be safely, reliably, and reproducibly accessed using a percutaneous parapedicular access technique. The technique presented represents a relatively avascular and aneural approach to vertebral body.

Intraoperative mapping of the trigeminal nerve root: technique and application in the surgical management of facial pain.

A method for intraoperative topographic mapping of the trigeminal nerve root using electrophysiological methods is described. A series of 15 patients under general anesthesia during microvascular decompression and selective posterior fossa trigeminal rhizotomy was studied. This method was used to study the localization of fibers of individual subdivisions of the intradural portion of the trigeminal nerve and as a guide for performing physiologically controlled, selective, microsurgical trigeminal rhizotomy.

Meningioma in congenital adrenal hyperplasia.

A diversity of malignancies have been reported in patients with congenital adrenal hyperplasia. We report a case of multiple meningiomas, tumors which are more common in females and reported to have sex steroid receptors, in a 46,XX male (severe female hermaphrodite raised as a male) with 21-hydroxylase deficiency. The patient has been treated with glucocorticoids since 3 years of age and testosterone since puberty.

Repair of temporosphenoidal encephalocele with a vascularized split calvarial cranioplasty: technical case report.

A 54-year-old woman was referred for the evaluation and treatment of spontaneous cerebrospinal fluid rhinorrhea. Magnetic resonance imaging revealed a right anteromedial intrasphenoidal encephalocele with cisternography showing the flow of contrast into the sphenoid encephalocele. Transcranial surgical repair was performed. This included the use of a vascularized split-thickness calvarial graft fixated over the cranial base defect with a titanium microplate. The technical details of this repair are discussed. Ten cases of temporosphenoidal encephaloceles have been reported. The literature concerning this rare form of encephalocele is reviewed.

Somatosensory evoked potential. Monitoring during spinal surgery.

Somatosensory evoked potentials (SSEPs) have been used to help minimize neurologic morbidity during spinal surgery. While this is a sensory test it has been used as an inference of motor function. The failure to always achieve the latter goal has resulted in some pessimism regarding the value of this test. In this series of 161 operations in 150 patients, it was demonstrated that SSEPs were recordable under anesthesia in 87% of patients. Of these patients, 12% had their spinal surgery interrupted due to significant neurophysiologic changes; of these patients, 18% had new neurologic deficits postoperatively. There were no cases with new neurologic deficits who had no changes in their SSEPs. It was concluded that SSEP monitoring may be helpful in identifying potentially neurologically threatening surgical maneuvers in a significant number of patients.

Neurophysiologic monitoring during cranial base surgery.

The last decade has seen a rapid growth in surgical techniques directed at resection of skull base tumors. Lesions that were previously inoperable can now be resected either partially or in some cases completely. The morbidity in these procedures has diminished with increased surgical experience. Additional aids to successful surgical resection include intraoperative neurophysiologic monitoring techniques. The following text outlines methods of monitoring cranial nerve and brain function in a manner that is directly relevant to cranial base surgery in which so many structures are potentially at risk. These techniques permit the identification of nerves obscured by tumor before they may be inadvertently damaged, the repeated confirmation during tumor resection that a nerve is still functional, and infer the state of brain and brainstem function during the course of long surgical procedures to help signal vascular compromise, or the effects of brain retraction. These techniques can only help to enhance the safety of the long and complex procedures required for successful resection of tumors of the cranial base.

Evolution and advances of the lateral surgical approaches to cranial base neoplasms.

The evolution and advances of the lateral surgical approaches used for neoplasms of the cranial base involving the middle and posterior cranial fossa are reviewed. The lateral approaches available for access to the cranial base are diverse and are often used in combination. Approaches for tumors that are completely extradural, usually involving the temporal bone or infratemporal fossa, include the infratemporal fossa approach described by Fisch and the preauricular subtemporal-infratemporal fossa approach. Lateral approaches used to provide exposure of intradural tumors involving the clivus and traversing the middle and posterior cranial fossa are based on the following approaches: the frontotemporal orbitozygomatic, subtemporal/middle fossa, transpetrosal, lateral suboccipital, and transcondylar approaches. The great strides that have been made in the safe and effective surgical treatment of cranial base neoplasms are due, in part, to the availability of multiple surgical approaches and the ability to tailor the planned operative procedure to the precise location and extent of the cranial base tumor.

Surgical treatment of greater occipital neuralgia: an appraisal of strategies.

The surgical treatment of greater occipital neuralgia often involves diagnostic anesthetic blockade, followed by chemical or surgical ablation of the greater occipital nerve. The anatomy of this region was studied in microdissections of 2 cadaver specimens. The diagnosis and management of a series of 5 patients with greater occipital neuralgia is discussed. Two patients were treated with atlanto-epistrophic ligament decompression of the C2 dorsal root ganglion and nerve; four patients had C2 ganglionotomy performed. All patients in this series had immediate complete relief of pain following surgery. Patients were followed for a mean of 24 months (range 7-33 months). One patient had a recurrence of her original pain after 26 months following atlanto-epistrophic ligament decompression and required re-operation in the form of bilateral C2 ganglionotomy. All patients experienced transient nausea and dizziness in the several days following surgery. One patient had an incisional cerebrospinal fluid leak. Microsurgical C2 gangliotomy is advocated as the preferred surgical treatment of greater occipital neuralgia of idiopathic origin.

Transfacial transpterygomaxillary access to foramen rotundum, sphenopalatine ganglion, and the maxillary nerve in the management of atypical facial pain.

Post-traumatic atypical facial pain syndromes are refractory to medical therapy and thus challenging to treat. Some of these patients have a facial causalgia syndrome that may include autonomic as well as trigeminal fibers as the anatomic mediators. A procedure that may be of both diagnostic and therapeutic benefit is a nerve block in the region of the foramen rotundum. This allows access to both the maxillary nerve and the sphenopalatine ganglion. A simple technique developed to perform this procedure is described, and the results in a series of six patients are presented.

The trigeminal evoked potential: Part I. Long-latency responses in awake or anesthetized subjects.

Trigeminal evoked potentials have been elicited with differing methodologies that render responses almost as numerous as the number of laboratories reporting them. Forty-six trigeminal nerves were studied to investigate trigeminal evoked potentials in 20 awake, normal subjects and 20 patients undergoing surgery with general anesthesia. A comparison was made between different methods of surface stimulation and subdermal stimulation. It was concluded that these techniques had no practical use in intraoperative monitoring.

The trigeminal evoked potential: Part II. Intraoperative recording of short-latency responses.

Short-latency (< 10 msec) trigeminal evoked potentials were studied intraoperatively in 31 patients under general anesthesia. Stimulation was performed peripherally in the face as well as centrally at the trigeminal nerve root entry zone. Recordings were made directly from the trigeminal root entry zone and far field from the scalp. Two principal negative deflections were noted, N1.6 and N2.6; and two waves that were less constantly identified were N.9 and N4-6. The latencies of these responses necessitated an extra-axial origin. It was concluded that this technique provided the ability to monitor the integrity of the extra-axial trigeminal nerve, but not the central trigeminal circuitry.

Rapid polymerizing fibrin glue from autologous or single-donor blood: preparation and indications.

A recipe for the preparation of a rapid polymerizing fibrin glue from single-donor or autologous blood products is presented. An in vitro investigation of different recipes with study of polymerization times, consistency, and in vitro survival of the product is described. The preparation in the operating room and the indications for clinical use of this glue in neurosurgery are discussed. The results of its use in a series of 38 patients is presented, including those undergoing surgery of the skull base, pituitary gland, cranial nerves, and the spine.

Cervical myelopathy in diffuse idiopathic skeletal hyperostosis. Case report.

The case of a rapidly progressive cervical myelopathy in a 64-year-old man is presented. Radiological studies revealed a partial extradural block, which at surgery was found to be a focal fibrous, calcified mass associated with the ligamentum flavum. On the basis of the underlying disorder of diffuse idiopathic skeletal hyperostosis (DISH), the etiology of this compression was concluded to be focal fibrous proliferation and dystrophic calcification. The neurological complications of DISH are reviewed. The authors are not aware of any other reports of this cause of myelopathy associated with DISH.