Citations

AbstractOBJECTIVE:The purpose of this study was to describe the natural history of tethered cord in patients who have undergone meningomyelocele repair.METHODS:We performed a retrospective review of 45 patients with a history of neonatal meningomyelocele repair who subsequently developed symptoms of tethered cord. Symptoms of tethered cord in this cohort consisted of the development of bladder spasticity or orthopedic foot deformity. None of these patients were treated with cord untethering; instead, they were treated symptomatically.RESULTS:On follow-up, 40 (88.9%) of these patients subsequently required additional orthopedic or urological procedures because of further symptoms of tethered cord. The incidence of progression of tethered cord syndrome is 27.5, 40, and 60% at 1, 2, and 5 years, respectively.CONCLUSION:Although this study does not address the question whether cord untethering will prevent further symptom development, these results do provide a strong rationale for consideration of an untethering procedure in patients with repaired meningomyelocele at the time of the onset of symptoms of tethered cord.

Abstract OBJECTIVE AND IMPORTANCE A case of acutely symptomatic epidural hematoma caused by metastatic hepatocellular carcinoma (HCC) to the cranium is reported. This is a rare case of metastatic HCC without known primary presenting as an epidural hematoma. CLINICAL PRESENTATION The patient presented with an acute onset of headache, aphasia, and right hemiparesis 2 weeks after he experienced minor trauma to the cranium. An emergency computed tomographic scan of the head revealed the presence of a left parietal epidural hematoma. INTERVENTION An emergency evacuation of the epidural hematoma was performed, and metastatic HCC was diagnosed. CONCLUSION The patient's neurological deficits were reversed with surgical intervention, and he is now undergoing palliative chemotherapy. This was the first clinical manifestation of HCC in this patient. This case reaffirms the neurosurgeon's role in the complex, multidisciplinary care of patients with craniospinal metastasis.

Abstract OBJECTIVE The proper treatment for patients with cyst formation after arteriovenous malformation radiosurgery is unknown. METHODS The treatment of six patients who developed cysts after arteriovenous malformation radiosurgery is described. Four patients had undergone gamma knife radiosurgery (two patients developed cysts after repeat procedures), and two patients had undergone linear accelerator-based radiosurgery. The median prescription isodose volume at the time of the first radiosurgical procedure was 13.2 cm3 (range, 8.0–28.7 cm3). RESULTS The cysts were discovered a median of 48 months (range, 24–89 mo) after radiosurgery. Three patients were originally without symptoms, and observation with serial imaging was performed; two of those patients developed symptoms 13 and 40 months later, whereas one patient has remained without symptoms for 51 months. Initial treatments for patients with symptomatic cysts included cyst aspiration (n = 3) and placement of a cystoperitoneal shunt (CPS) (n = 2). The median cyst volume was 14 cm3 (range, 4–63 cm3). Cyst recurrence occurred within 2 months for patients who underwent aspiration alone, necessitating placement of a CPS. Shunt placement eliminated the cysts for four patients, at a median follow-up time of 16 months (range, 9–27 mo). One patient's cyst persisted despite CPS placement, and cyst excision was performed. No morbidity occurred with any of the cyst treatments. CONCLUSION Cyst formation after arteriovenous malformation radiosurgery may occur many years after the procedure. Although most symptomatic cysts can be effectively treated with CPSs, cyst excision may be necessary if the mass effect is not relieved with the less invasive approach.

Abstract OBJECTIVE To report presenting clinical symptoms, previous medical history, and survival rates for people with saccular intracranial aneurysms (IAs), in a defined population. METHODS The medical records of all residents of Olmsted County, Minnesota, with possible IAs were reviewed. Clinical manifestations at the time of diagnosis, previous medical history, demographic factors, and survival rates after diagnosis were determined. RESULTS Of 270 people with IAs detected between 1965 and 1995, 188 exhibited symptoms at the time of diagnosis, including 74% of women and 63% of men (P = 0.054). Intracranial hemorrhage (ICH) was the most common presenting symptom (60% of all patients and 86% of patients who exhibited symptoms), followed by cranial nerve palsy, transient ischemic attacks, and seizures. Survival rates after detection (with the exclusion of cases that were first detected during autopsies) were dependent on the occurrence of ICH; 23% of patients who presented with ICH died by 1 day after diagnosis, compared with 5% of those who did not exhibit symptoms or exhibited symptoms but without ICH at presentation. At 5 years, 44.7% of patients with hemorrhage had died, compared with 29.4% of patients with symptoms other than hemorrhage. After the first 24 hours after detection, survival rates did not differ significantly for those presenting with or without hemorrhage. Predictors of better survival rates also included lower age and later calendar year of presentation. CONCLUSION This study provides the first data on aneurysm characteristics, clinical symptoms, and survival rates among people with IAs in a defined population. During the study period, most aneurysms were detected in the context of an aneurysm-related symptom (particularly among women), with a large proportion of patients presenting with ICH. After the acute phase of hemorrhage, long-term survival rates among people with IAs were similar for those presenting with or without ICH.

Abstract OBJECTIVE Stereotactic radiosurgery is being used with more frequency in the management of patients with trigeminal neuralgia. To improve facial pain outcomes, many centers have increased the prescribed radiation dose to the trigeminal nerve. METHODS Between April 1997 and December 1999, 68 patients underwent radiosurgery for trigeminal neuralgia with use of the Leksell gamma knife (Elekta Instruments, Norcross, GA) and a single 4-mm isocenter of radiation. Twenty-seven patients (40%) received 70 Gy (low dose) of irradiation and 41 patients (60%) received 90 Gy (high dose). The groups were similar with regard to age, sex, duration of pain, number of prior surgeries, and preexisting trigeminal deficits. The primary facial pain outcomes for analysis were excellent (pain-free, no medications) and good (pain-free, reduced medications). The mean length of follow-up after radiosurgery was 14.4 months (range, 2–36 mo). RESULTS At last follow-up examination, 11 (41%) of the 27 patients with low-dose radiosurgery remained pain-free compared with 25 (61%) of the 41 patients with high-dose radiosurgery (P = 0.17). Additional surgery was performed in 12 low-dose patients (44%) and 8 high-dose patients (20%) (P = 0.05). High-dose radiosurgery was associated with an increased rate of permanent trigeminal nerve dysfunction (54% versus 15%, P = 0.003). Bothersome dysesthesias occurred in 13 high-dose patients (32%), whereas only 1 low-dose patient had this complication (P = 0.01). Three high-dose patients (8%) developed corneal numbness after radiosurgery. Pain recurred with more frequency in patients not developing trigeminal nerve dysfunction after radiosurgery (9 of 22 patients, 41%) compared with those who sustained facial numbness, paresthesias, or dysesthesias (4 of 27 patients, 15%); however, the difference was not statistically significant (P = 0.08). CONCLUSION Higher doses of radiation may correlate with better facial pain outcomes after radiosurgery for trigeminal neuralgia. However, the incidence of significant trigeminal nerve dysfunction is markedly increased after radiosurgery for patients receiving high-dose radiosurgery. Because of the nonselective nature of this ablative technique, dose prescription should be limited to less than 90 Gy.

ABSTRACT OBJECTIVE Remote cerebellar hemorrhage (RCH) is an infrequent and poorly understood complication of supratentorial neurosurgical procedures. We retrospectively compared 42 patients who experienced RCH with a case-matched control cohort, to delineate risk factors associated with the occurrence of this complication. METHODS Between 1988 and 2000, 42 patients experienced RCH after supratentorial neurosurgical procedures at our institution. Diagnoses were made on the basis of postoperative computed tomographic or magnetic resonance imaging findings in all cases. The medical records for these patients were reviewed and compared with those for a control cohort of 43 patients, matched for age, sex, surgical lesion, and type of craniotomy, who were treated during the same period. RESULTS RCH most commonly occurred after frontotemporal craniotomies for unruptured aneurysm repair or temporal lobectomy and was frequently an incidental finding on postoperative computed tomographic scans. However, some cases of RCH were associated with significant morbidity, and two patients died. Preoperative aspirin use and elevated intraoperative systolic blood pressure were significantly associated with RCH (P = 0.026 and P = 0.036, respectively). Pathological findings for two cases demonstrated hemorrhagic infarctions in both. CONCLUSION RCH most commonly follows supratentorial neurosurgical procedures, performed with the patient in the supine position, that involve opening of cerebrospinal fluid cisterns or the ventricular system (such as unruptured aneurysm repair or temporal lobectomy). Preoperative aspirin use and moderately elevated intraoperative systolic blood pressure are potentially modifiable risk factors associated with the development of RCH. Although RCH can cause death or major morbidity, most cases are asymptomatic or exhibit a benign course. Cerebellar “sag” as a result of cerebrospinal fluid hypovolemia, causing transient occlusion of superior bridging veins within the posterior fossa and consequent hemorrhagic venous infarction, is the most likely pathophysiological cause of RCH.

ABSTRACT OBJECTIVE To determine local control (LC) and complication rates for patients with intracranial meningiomas who underwent radiosurgery. METHODS One hundred ninety consecutive patients with 206 meningiomas underwent radiosurgery between 1990 and 1998. One hundred forty-seven tumors (77%) involved the cranial base. The median age at the time of radiosurgery was 58 years (range, 20–90 yr). There were 126 female patients (66%). One hundred twelve patients (59%) had undergone one or more previous operations (median, 1; range, 1–5). Twenty-two patients (12%) had either atypical (n = 13) or malignant (n = 9) tumors. The median prescription isodose volume was 8.2 cm3 (range, 0.5–50.5 cm3), and the median tumor margin dose was 16 Gy (range, 12–36 Gy). The median imaging and clinical follow-up periods were 40 and 47 months, respectively. RESULTS Overall survival rates for the entire cohort at 5 and 7 years were 82 and 82%, respectively; cause-specific survival rates at 5 and 7 years were 94 and 92%, respectively. The cause-specific survival rates at 5 years for patients with benign, atypical, and malignant tumors were 100, 76, and 0%, respectively (P < 0.0001). The 5-year LC rate was 89%, with 114 tumors (56%) decreasing in size. LC rates were correlated with tumor histological features (P < 0.0001); patients with benign tumors exhibited a 5-year LC rate of 93%, compared with 68 and 0% for patients with atypical or malignant meningiomas, respectively. No correlation was observed between radiation dose and LC rate. Twenty-four patients (13%) experienced treatment-related complications, including cranial nerve deficits (8%), symptomatic parenchymal changes (3%), internal carotid artery stenosis (1%), and symptomatic cyst formation (1%). Only six patients (3%) exhibited decreases in functional status that were directly related to radiosurgery. Tumor volume, tumor margin dose, or previous radiotherapy was not associated with the development of radiation-related complications. CONCLUSION Radiosurgery is an effective management strategy for many patients with meningiomas. Patients with atypical or malignant tumors exhibit high recurrence rates despite the use of radiosurgery, and these patients continue to exhibit worse cause-specific survival rates despite aggressive treatment, including surgery, external-beam radiotherapy, and radiosurgery. Further study is needed to determine the tumor control and complication rates 10 years or more after meningioma radiosurgery.

Abstract OBJECTIVE AND IMPORTANCE We report the first case of combined oligodendroglioma and pleomorphic xanthoastrocytoma. CLINICAL PRESENTATION A female college student and competitive cross-country runner presented to the Mayo Clinic at age 18 years with complaints of progressive headache and visual disturbances. Neuroimaging revealed a heavily calcified left parieto-occipital mass with focal enhancement and remodeling of the overlying calvarium. INTERVENTION A histological examination of the nearly gross total resection specimen disclosed a low-grade oligodendroglioma discretely abutting a superficially situated focus of pleomorphic xanthoastrocytoma. Ten months thereafter, a recurrence was suspected on the basis of the detection of a new focus of nodular enhancement. This lesion stabilized after radiation therapy, and the patient is well, without apparent residual disease 2.8 years after surgery. CONCLUSION This unique neoplasm is presumed to represent a collision tumor, its biological behavior being similar to that of oligodendroglioma alone. However, the possibility of an unusual, mixed oligoastrocytoma with pleomorphic xanthoastrocytoma as the astrocytic component cannot be excluded entirely. Potentially, both components have the capacity for recurrence and anaplastic transformation.