Ventral intradural endodermal cyst in the cervical spine treated with anterior corpectomy--case report.

A 14-year-old girl who presented with an endodermal cyst manifesting as severe neck and shoulder pain along with vesicorectal disturbances. Cervical magnetic resonance imaging showed a slightly enhanced intradural cyst at the C6-7 level in the ventral side of the spinal canal, with significant dorsal shortening and thinning of the spinal cord. Anterior corpectomy was chosen because of the dorsal effacement of the spinal cord. The cyst wall was subtotally removed to avoid damage to the normal spinal cord. After cyst removal, the iliac bone and an anterior cervical plate were used for anterior fusion. Postoperatively, her pain subsided without neurological deficits. The histological diagnosis was endodermal cyst. The cyst did not recur during a follow-up period of 18 months. Endodermal cysts are rare congenital lesions of the spine lined by endodermal epithelium. The natural history of this lesion is unclear, and the surgical strategy for the approach route and the extent of removal of the cyst wall remain controversial. We suggest that the anterior approach may allow a safer and more effective surgical route for the treatment of ventrally located endodermal cyst compared to the posterior approach.

"Kissing" brainstem cavernous angiomas removed using a trans-fourth ventricular floor approach--case report.

A 39-year-old woman presented with a rare case of "kissing" brainstem cavernomas formed by separate lesions enlarging with simultaneous recurrent hemorrhages, which was successfully treated by staged resection using a trans-fourth ventricular floor approach. She had a familial history of cerebral cavernous angioma, and presented with a history of four episodes of sudden neurological deterioration. Magnetic resonance (MR) imaging obtained at each neurological event demonstrated two distinct brainstem cavernomas located in the pontine tegmentum and ventral part of the lower pons, both of which enlarged stepwise caused by simultaneous recurrent hemorrhages. Both cavernomas contacted and formed "kissing" lesions. She underwent midline suboccipital craniotomy in the prone position. The cavernoma in the pontine tegmentum was resected through a trans-fourth ventricular floor approach. Although "kissing" formation appeared on preoperative MR imaging, parenchyma was identified at the bottom of the removal cavity of the dorsal lesion, and resection was terminated. MR imaging following the first surgery revealed complete resection of the pontine tegmentum cavernoma and the ventral pontine cavernoma, which was located adjacent to the bottom of the removal cavity and aligned in same direction along the fourth ventricular floor approach. At 10 days after first surgery, she underwent the same procedure with the aid of neuronavigation to resect the ventral pontine cavernoma through the former removal cavity. This approach through the previous removal route, particularly for resection of "kissing" lesions which are difficult to access in the brainstem, is a technically feasible microsurgical procedure.

Intraoperative Monitoring of Motor Evoked Potential for the Facial Nerve Using a Cranial Peg-Screw Electrode and a "Threshold-level" Stimulation Method.

Transcranial motor evoked potential (MEP) for the facial nerve (facial MEP) has been recognized as a good method for quantitative monitoring of facial nerve function in skull base surgery. To improve the feasibility and safety of facial MEP monitoring, a peg-screw electrode and a "threshold-level" method were investigated. From 2007 to 2009, intraoperative facial MEP monitoring with the peg-screw electrode and threshold-level method was successfully achieved in 26 of 29 patients who underwent surgery for the posterior fossa extra-axial tumor. The relationship between the change in the facial MEP threshold level and the postoperative function of the facial nerve was analyzed in 23 patients who had no facial palsy preoperatively. There were no complications associated with facial MEP monitoring. Nine patients who had stable facial MEP threshold had no facial palsy. Fourteen patients who had worsened but measurable facial MEP threshold had mild palsy at discharge. Two of three patients who had severely worsened and unmeasurable facial MEP threshold had severe facial palsy. The change in the facial MEP was well correlated with the postoperative facial function. The peg-screw electrode and threshold-level method are good options for facial MEP monitoring.

Surgical experience with resection en bloc of intramedullary astrocytomas and ependymomas in the cervical and cervicothoracic region.

We performed 8 operations on 7 patients with benign intramedullary astrocytomas and ependymomas in the cervical and cervicothoracic region. All patients initially underwent gross total tumor resection en bloc. One patient with an astrocytoma showed tumor recurrence postoperatively, and underwent a second operation resulting in subtotal removal. The follow-up after the initial surgery ranged from 2.7 to 19.7 years (mean 8.5 years). Symptomatic improvement was observed in 6 patients after the initial operation. Two patients showed postoperative neurological deterioration, one with an ependymoma and the other after the second operation. No operative complications or deaths, nor postoperative respiratory dysfunction occurred. Benign intramedullary astrocytomas and ependymomas of the cervical and cervicothoracic spinal cord can be treated by radical resection en bloc with a low morbidity and recurrence, as well as acceptable outcomes. We describe here the surgical technique for en bloc tumor removal.

Clinical application of robotic telemanipulation system in neurosurgery. Case report.

The NeuRobot is a telecontrolled microscopic micromanipulator system designed for neurosurgical procedures. The unit houses a three-dimensional endoscope and three robot arms that the surgeon operates without direct contact with the patient. The authors have successfully performed robotics-assisted neurosurgical procedures by using the NeuRobot in a 54-year-old man who had a recurrent atypical meningioma. Following the usual preparation of craniotomy and opening of the dura mater, a portion of the tumor was removed using the NeuRobot with the aid of microscopic observation. No complication related to the use of the NeuRobot was encountered and the patient's postoperative course was uneventful. Although various kinds of robots have been developed for use in neurosurgery in recent years, a robotic telemanipulation system capable of performing several surgical tasks has not previously been introduced to clinical neurosurgery. This is the first case report in which neurosurgical manipulation by a robotics system is described.