Treatment of failed Adult Chiari Malformation decompression with CSF drainage: observations in six patients.

OBJECTIVE: We report the use of CSF drainage for the management of failed Adult Chiari Malformation (ACM) decompression. METHODS: All patients with more than one year follow-up after treatment of their failed ACM were included in this study. They underwent initial decompression between September 1998 and April 2000. Clinical and radiological data were collected initially and at recurrence. Lumbar punctures (LP) were done at recurrence for diagnostic and therapeutic purposes. Opening pressures and symptomatic relief were recorded. Therapeutic options included intermittent LP and ventriculo-peritoneal shunting (VPS). RESULTS: There were 6 patients (5 females and one male). Their age ranged from 19 to 43 years. Tonsillar descent ranged from 5 to 21 mm. The symptoms recurred 1.5 to 9 months postoperatively (average 5.6 months). Postoperative imaging revealed the presence of CSF flow behind the tonsils and the formation of a retrotonsillar neocistern in all patients. On LP, the opening pressure ranged from 17 to 31 cm of water (average 23 cm). All patients improved after CSF drainage, and four patients underwent VPS. The other patients were treated with repeat LP+/-Acetazolamide. There was significant improvement in all patients, with 18 months follow-up after CSF drainage (range 16-21 months). CONCLUSIONS: Our results suggest a role for CSF drainage in the treatment of some patients with failed ACM surgery. Possible explanations for the failure of ACM surgery in this subgroup include: surgical complications leading to neural hydrodynamic alteration, inadequate initial surgery, and coexistence with another pathology, possibly a mild form of intracranial hypertension. More prospective and hydrodynamic studies are needed to further clarify these issues.

Definition of the adult Chiari malformation: a brief historical overview.

With the widespread use of newer neuroimaging techniques and modalities, significant tonsillar herniation is being diagnosed in more than 0.5% of patients, some of whom are asymptomatic. This puts the definition of the adult Chiari malformation to the test. The author provides a historical review of the evolution of the definition of the adult Chiari malformation in the neurosurgery, radiology, and pathology literature.

A reappraisal of surgery for orbital tumors. Part I: extraorbital approaches.

Orbital lesions are variable in nature and location. Their management can be challenging, and surgical intervention is often needed. Although a significant percentage of these tumors are treated by the ophthalmologist alone, collaboration with a neurosurgeon is often required, especially for tumors that are located deep within the orbit, are large, or have an intracranial extension. Technical advances and modifications in surgical technique have decreased surgery-related morbidity and increased its success. The authors describe their rationale in the choice of a surgical approach, the surgical techniques for extraorbital approaches, and the new surgical adjuvants.

Surgery for orbital tumors. Part II: transorbital approaches.

Orbital tumors can be excised or biopsy samples obtained via transorbital approaches, especially those located in the anterior two thirds of the orbit. The indications and various surgical steps will be reviewed for the anterior, the anteromedial, and the lateral approaches. Some of these approaches can be combined or extended to accommodate large or deep-seated tumors.

Occipitocervical fusion following the extreme lateral transcondylar approach.

BACKGROUND: Modern cranial base approaches to the clivus and foramen magnum may threaten the stability of the cranio-cervical junction. This necessitates stabilization and fusion in some cases. We studied occipitocervical fusion after extreme lateral transcondylar approaches. METHODS: Twenty-seven patients underwent an extreme lateral transcondylar approach over a 2-year period. Two patients were excluded because of prior occipitocervical fusion. The pathological diagnosis was meningioma in ten patients, chordoma in six patients, neurofibroma in two, and 10 patients had other tumoral and nontumoral pathologies. RESULTS: Eight patients required occipitocervical fusion and stabilization. Five of six patients with chordomas required fusion, whereas no patient with a meningioma underwent fusion. All the patients who were fused had more than 70% resection of their occipital condyle. No patient with resection of less than 70% of the occipital condyle required fusion. Significant interference of the surgical construct with follow-up imaging was seen only in the patient in whom a stainless steel Steinman pin was used. CONCLUSION: One third of patients will require fusion after extreme lateral transcondylar approaches. Most patients with less than 70% resection of the condyle remain stable without need for surgical intervention, whereas complete resection necessitates fusion in most cases.

Cerebral metastasis of a uterine leiomyosarcoma--case report.

A 38-year-old female presented with sudden neurological deterioration 6 years after an operation and chemotherapy for uterine leiomyosarcoma. An extremely rare metastasis of the uterine leiomyosarcoma to the brain was identified and totally resected. Whole brain irradiation (50 Gy) was given. A recurrence of the metastasis was resected 10 weeks later. She ultimately died of a second recurrence. Aggressive surgical management of cerebral metastasis of uterine leiomyosarcoma may achieve an improved outcome.

Treatment of symptomatic cervical carotid dissections with endovascular stents.

OBJECTIVE: Symptomatic dissections of the cervical carotid artery (CCA) can be spontaneous or secondary to trauma and may be associated with pseudoaneurysms. Surgical treatment is often difficult or unavailable. We report the successful use of endovascular stents in the treatment of symptomatic dissection of the CCA. METHODS: Five consecutive patients with symptomatic CCA dissection were seen at our institution. There were four female patients and one male patient, ranging in age from 19 to 56 years. One dissection was spontaneous. The others were secondary to a gunshot wound (one patient), blunt neck trauma (two patients), and endovascular treatment of atherosclerotic carotid bifurcation disease (one patient). Balloon-expandable and self-expanding stents were placed via a transfemoral approach. RESULTS: Success in restoring the carotid lumen with two to five stents in each patient was angiographically demonstrated. There were no procedure-related complications. All patients experienced significant clinical improvement within the first 24 hours and complete long-term recovery. CONCLUSION: Symptomatic dissections of the CCA can be successfully treated by using endovascular stents.

Bilateral vertebral artery occlusion following cervical spine trauma--case report.

A 41-year-old female presented with a rare case of bilateral vertebral artery occlusion following C5-6 cervical spine subluxation after a fall of 30 feet. Digital subtraction angiography showed occlusion of the bilateral vertebral arteries. Unlocking of the facet joint, posterior wiring with iliac crest grafting, and anterior fusion were performed. The patient died on the 3rd day after the operation. This type of injury has a grim prognosis with less than a third of the patients achieving a good outcome.

Primary dural leiomyosarcoma in a patient infected with human immunodeficiency virus: case report.

INTRODUCTION: We report the magnetic resonance imaging, angiographic, and immunohistochemical characteristics of a dural leiomyosarcoma in a patient infected with human immunodeficiency virus. METHODS AND RESULTS: A 38-year-old homosexual man presented with a recent history of headaches. Magnetic resonance imaging of the brain revealed an enhancing dural based right lateral wing mass that was thought to be a meningioma. The tumor had a signal intensity similar to the adjacent gray matter on T1-, T2-, and proton-weighted images. Angiography revealed that the tumor was vascular, supplied by the middle meningeal artery, but with contrast puddling as if there were small vascular lakes within the tumor. This evoked the possibility of a cavernous hemangioma. A craniotomy was performed, and the mass was resected. The pathological finding was consistent with a leiomyosarcoma. Immunohistochemistry revealed that the tumor was positive for alpha smooth muscle actin. Repeat testing for human immunodeficiency virus 2 months postoperatively was positive. Dural leiomyosarcomas are thought to take origin from the smooth muscles of the blood vessel walls. Another possible source is pluripotential mesenchymal cells. There may be an association with immunosuppression. CONCLUSION: Primary dural leiomyosarcomas simulate meningiomas on preoperative magnetic resonance images. They should be included in the differential diagnosis of dural based enhancing lesions.

Vasospasm after cranial base tumor resection: pathogenesis, diagnosis, and therapy.

OBJECTIVE: Cerebral vasospasm is well known to occur after various cerebral neurosurgical events that cause subarachnoid hemorrhage. However, cerebral vasospasm can occur after cranial base tumor resection. We present a series of nine patients with angiographically evident vasospasm that was clinically symptomatic in eight of them. METHODS: A total of 470 consecutive patients with cranial base tumors were operated in our institution between April 1993 and December 1996. Nine had evidence of cerebral vasospasm postoperatively (1.9% of the total population), of whom eight were asymptomatic. There were seven males and two females with an age range of 33 to 65 years (average 48.5 years). There were seven meningiomas, one chordoma, and one trigeminal schwannoma. RESULTS: Vasospasm manifested clinically 1 to 30 days postoperatively in eight patients. Most patients were symptomatic within 7 days. In the ninth case, surgery was delayed when asymptomatic vasospasm was noted on an angiogram before second stage surgery. Symptoms included altered mental status in four patients, hemiparesis in three patients (one patient had both hemiparesis and altered mental status), and monoparesis in two patients. Factors that were found to correlate with a higher incidence of vasospasm were tumor size, total operative time, vessel encasement, vessel narrowing, and preoperative embolization. All eight patients with symptomatic vasospasm were treated with hypertensive, hypervolemic, hemodilutional (HHH) therapy. Five patients also underwent intraluminal angioplasty, in conjunction with papaverine in one case. One patient received intraarterial papaverine alone. Angiographic results were good in all patients. Significant clinical improvement was seen in six of the eight symptomatic cases. CONCLUSION: Delayed neurological deterioration in a patient who has undergone cranial base tumor surgery not explained by an intracranial mass lesion should be promptly investigated with angiography. If vasospasm is diagnosed, it should be treated aggressively with hypertensive, hypervolemic, hemodilutional therapy and early angioplasty.

Surgical anatomy of the infratemporal fossa: the styloid diaphragm revisited.

INTRODUCTION: The infratemporal fossa (ITF) gives passage to most major cerebral vessels and cranial nerves. Dissection of the ITF is essential in many of the lateral cranial base approaches and in exposure of the high cervical internal carotid artery (ICA). We reviewed the surgical anatomy of this region. METHODS: Direct foraminal measurements were made in seven dry skulls (14 sides), and the relationship of these foramina to each other and various landmarks were determined. Ten ITF dissections were performed using a preauricular subtemporal-infratemporal approach. Preliminary dissections of the extracranial great vessels and structures larger than 1 cm were performed using standard macroscopic surgical techniques. Dissection of all structures less than 1 cm was conducted using microsurgical techniques and instruments, including the operating microscope. The anatomic relationships of the muscles, nerves, arteries, and veins were carefully recorded, with special emphasis regarding the relationship of these structures to the styloid diaphragm. The dissection was purely extradural. RESULTS: The styloid diaphragm was identified in all specimens. It divides the ITF into the prestyloid region and the retrostyloid region. The prestyloid region contains the parotid gland and associated structures, including the facial nerve and external carotid artery. The retrostyloid region contains major vascular structures (ICA, internal jugular vein) and the initial exocranial portion of the lower Cranial Nerves IX through XII. Landmarks were identified for the different cranial nerves. The bifurcation of the main trunk of the facial nerve was an average of 21 mm medial to the cartilaginous pointer and an average of 31 mm medial to the tragus of the ear. The glossopharyngeal nerve was found posterior and lateral to stylopharyngeus muscle in nine cases and medial in only one. The vagus nerve was consistently found in the angle formed posteriorly by the ICA and the internal jugular vein. The spinal accessory nerve crossed anterior to the internal jugular vein in five cases and posterior in another five cases. It could be located as it entered the medial surface of the sternocleidomastoid muscle 28 mm (mean) below the mastoid tip. The hypoglossal nerve was most consistently identified as it crossed under the sternocleidomastoid branch of the occipital artery 25 mm posterior to the angle of the mandible and 52 mm anterior and inferior to the mastoid tip. CONCLUSION: The styloid diaphragm divides the ITF into prestyloid and retrostyloid regions and covers the high cervical ICA. Using landmarks for the exocranial portion of the lower cranial nerves is useful it identifying them and avoiding injury during approaches to the high cervical ICA, the upper cervical spine, and the ITF.

The predictive value of intraoperative somatosensory evoked potential monitoring: review of 244 procedures.

INTRODUCTION: There is some controversy regarding the value of intraoperative neurophysiological monitoring in predicting postoperative neurological deficits. We discuss our experience with the use of intraoperative somatosensory evoked potentials (SSEPs) during surgery of cranial base tumors. METHODS: We retrospectively reviewed all of the procedures that had been performed for the resection of cranial base tumors from July 29, 1993, through March 16, 1995. One hundred ninety-three consecutive patients had undergone a total of 244 procedures. SSEP waveforms were classified as follows: Type I, no change; Type II, change that reverts to baseline; Type III, change that does not revert to baseline; and Type IV, complete flattening of the SSEP waveform without improvement. Two patients had no waveforms from the beginning of the case (Type V) and were excluded from further analysis. New immediate postoperative neurological deficits were recorded. RESULTS: There were 64 male and 129 female patients, with a mean age of 46.6 years. One hundred seventy-seven patients had Type I SSEP waveforms, 13 of whom had postoperative deficits (7%). Fifty-six patients had Type II SSEPs, and nine (16%) of them had postoperative neurological deficits. Six patients had Type III SSEPs, and three had Type IV SSEPs, all of whom (100%) had postoperative deficits. There was a correlation between SSEP type and the results of the postoperative neurological examinations. The positive predictive value is 100%, and the negative predictive value is 90%. Although a change in the waveform that did not revert to baseline (Types III and IV) always predicted a postoperative deficit, a normal waveform did not always rule out postoperative deficits. Pathological abnormality, vessel encasement, vessel narrowing, degree of cavernous sinus involvement, brain stem edema, middle fossa location, final amount of resection, age, and tumor size correlated with a high predictive value of SSEP monitoring on univariate analysis (P < 0.05). None of these variables correlated significantly on multivariate analysis (P > 0.05), although brain stem edema was close (P = 0.0571). CONCLUSION: Intraoperative SSEPs have a high positive predictive value during surgery for cranial base tumors, but they do not detect all postoperative deficits.

Anatomy of the frontotemporal branch of the facial nerve and indications for interfascial dissection.

INTRODUCTION: Many studies have been conducted of the surgical anatomy of the frontotemporal branch of the facial nerve (FTBFN). However, very few have addressed the indications for interfascial dissection. When the zygomatic arch needs to be exposed, the interfascial approach is recommended to protect the FTBFN. With the transbasal or subfrontal approaches, however, when a bicoronal skin incision is used, the need for the interfascial approach is not clear. METHODS: We studied 10 temporal regions (5 cadaveric heads). We dissected the recognized fascial layers of the temporal region and the FTBFN. We performed a histological study in a sixth specimen. RESULTS: We observed the following. 1) The galea and the superficial layer of the deep temporal fascia become fused in a curved line from the lateral orbital border 2.8 cm above the zygomatic arch to a point 3 cm posterior to the inferolateral angle of the orbit. 2) After this transitional area of adherence, the subgaleal loose cellular layer is lost and is replaced by a fibrofatty tissue. 3) The FTBFN in its course above the zygomatic arch runs in this tissue layer without being protected by the galea. 4) Over the superolateral angle of the orbital rim, the galea protects FTBFN, and there are no subgaleal adhesions in that area. CONCLUSION: Ahove the zygomatic arch, the FTBFN is not protected by the galea. During bicoronal approaches, if only the superolateral angle of the orbital rim needs to be exposed and not the zygomatic arch, there is no need to protect the FTBFN using an interfascial approach.

Endodermal cysts of the posterior fossa. Report of three cases and review of the literature.

The pathogenesis of endodermal cysts of the posterior fossa is still incompletely understood. The authors reviewed three new cases and those reported in the literature to clarify the clinical, pathological, radiological, and surgical characteristics of these lesions. A total of 49 cases were reviewed. Details on demographic profiles, clinical characteristics, histopathological and radiological features, and surgical methods were collected. These cysts have a predominance in male patients (61%) and can occur at any age (birth-77 years). In patients with posterior fossa endodermal cysts there is a bimodal age distribution and headache is the most frequent complaint. On immunohistopathological examination, endodermal cysts were reactive for epithelial membrane antigen and for keratin immunostains whenever the latter were tested. The cysts were reactive for carcinoembryonic antigen in nine of 11 cases. Endodermal cysts were located anterior to the brainstem in 51% of cases and in the fourth ventricle in 21% of cases. They frequently appeared hypodense on computerized tomography scans, and in five cases, the lesion was missed. The cyst's appearance on magnetic resonance imaging is variable. Resection was complete in 19 cases and partial in 11; marsupialization was achieved in two cases. Three recurrences have been reported. Total excision with preservation of neurological function should be the goal. Cranial base approaches are helpful for surgical access in selected examples of these lesions.

Multiple meningiomas and intracranial aneurysms: a case report and review of the literature.

An extremely rare case with multiple meningiomas and multiple aneurysms is reported. This 48 year-old female had her meningiomas at the convexity and along the sphenoid wing, and intracranial aneurysms at the basilar tip, left middle cerebral artery bifurcation, and left pericallosal artery. All of them were shown by preoperative radiological evaluation. During the operation, two more meningiomas, again at the sphenoid wing and at the tentorium, were found. There was no evidence of either a connective tissue disease or neurofibromatosis.

The efficacy and safety of angioplasty for cerebral vasospasm after subarachnoid hemorrhage.

OBJECTIVE: Cerebral angioplasty is being increasingly used for symptomatic vasospasm secondary to subarachnoid hemorrhage. We attempted to determine the safety and efficacy of angioplasty for refractory vasospasm. We also looked at the influence of timing of angioplasty on outcome. METHODS: We retrospectively studied patients with subarachnoid hemorrhage who underwent angioplasty in our institution to determine the safety and the success rate achieved with this procedure. The study period extended from August 1993 until February 1997. Clinical and radiological data were collected, with emphasis on clinical improvement after angioplasty and its relationship with timing of intervention. Thirty-one patients with 43 aneurysms and one case of arteriovenous malformations were included. Their ages varied between 28 and 68 years, with an average age of 44 years. Five patients were assigned Hunt and Hess Grade IV, 15 were assigned Grade III, 7 were assigned Grade II, and 4 were assigned Grade I. All patients except two underwent angioplasty after aneurysm clipping or coiling. RESULTS: Angioplasty was performed an average of 6.9 days after the occurrence of subarachnoid hemorrhage, with a range from 1 to 14 days. It was performed early (within 24 h) after refractory clinical deterioration in 21 patients. A total of 81 vessels were dilated. Three angioplasty-related complications occurred: two femoral hematomas and one retroperitoneal hematoma. Clinical improvement was dramatic after 12 procedures, moderate after 11 procedures, and minimal or nonexistent after 9 procedures. There was a clear tendency toward more significant improvement in patients with earlier angioplasty (<24 h from onset of neurological deficit) (P=0.0038). At discharge, 8 patients had achieved good recoveries (Glasgow Outcome Scale score of 1), 11 had moderate disabilities (Glasgow Outcome Scale score of 2), and 10 had severe disabilities (Glasgow Outcome Scale score of 3). Two deaths were encountered, and they were unrelated to angioplasty. Follow-up was obtained for 27 patients: 25 had good outcomes, 1 was moderately disabled, and 1 died. There was no significant correlation between interval and outcome. CONCLUSION: Our results indicate that angioplasty is a safe and effective treatment for symptomatic vasospasm that is refractory to hyperdynamic hypervolemic therapy. When used early (<24 h), it leads to significant clinical improvement. However, the long-term outcome is good, even in cases of delayed angioplasty. The prevention of worsening of the cerebral ischemia and its extension to other territories may be the reason.

Cervical spinal cord injury during cerebral angiography with MRI confirmation: case report.

We report the first case of MRI-documented cervical spinal cord injury during cerebral angiography. A 54-year-old woman underwent an angiogram for subarachnoid hemorrhage. Her head was secured in a plastic head-holder. At the end of the procedure, she was found to have a left hemiparesis. MRI revealed high signal in the cervical spinal cord. The etiology may have been mechanical due to patient positioning, or toxic, from contrast medium injection in the vessels feeding the spinal cord, or a combination of both.

Intrathecal granuloma after implantation of a morphine pump: case report and review of the literature.

BACKGROUND: Intrathecal morphine pumps are being increasingly used in patients with benign pain who have a longer life expectancy than cancer patients. Newer complications may be encountered. CLINICAL PRESENTATION: We report a complication that occurred in a 48-year-old woman who presented with intractable lower back pain 18 months after morphine pump implantation. Magnetic resonance imaging of the lumbosacral spine revealed an intrathecal mass around the catheter. At surgery, an inflammatory mass was found without any evidence of neoplasia or infection. This is a very unusual complication of intrathecal morphine pumps. (Related animal and human studies are reviewed in this article.) CONCLUSION: Long-term use of implantable pumps may carry increased risks that are not observed during the short-term experience of cancer patients. Reimaging is important in evaluating patients who have developed uncontrollable pain and new neurologic findings.

The role of spinal fusion in surgery for lumbar spinal stenosis: a review.

The authors undertook a review of the literature and analysis of the local surgical experience for lumbar stenosis to define the role of simultaneous arthrodesis in the treatment of patients undergoing decompression for spinal stenosis. The restrained use of spinal fusion is recommended in spinal stenosis surgery because of the coexisting medical problems in the elderly patient population and the higher associated complication rate with spinal fusion and instrumentation. A spinal fusion is recommended when decompression is performed in an area of segmental instability as manifested by gross movement on flexion--extension radiographs; when the decompression coincides with an area of degenerative instability, as with scoliosis or spondylolisthesis; or when the decompression creates an iatrogenic instability by the disruption of the posterior elements. The use of spine instrumentation as an adjunct to fusion is recommended when an area of degenerative instability shows evident gross instability or has had additional destabilizing procedures, such as a discectomy or a facetectomy. Spinal fusion is not recommended for a routine decompressive laminectomy for lumbar stenosis or in the case of stable degenerative deformities. New fusion techniques may improve the outcome and decrease the morbidity associated with contemporary methods of spinal fusion and instrumentation.