Delayed symptom progression after ventriculoperitoneal shunt placement for normal pressure hydrocephalus

Normal pressure hydrocephalus (NPH) is generally treated with ventriculoperitoneal shunts (VPS), with improved symptoms in the majority of patients. We performed a retrospective chart review study in order to describe patterns of, and risk factors for, delayed symptom progression after initially successful VPS placement. 69 consecutive patients underwent VPS placement for NPH, and were followed for a minimum of 12 months postoperatively. 55 patients (80%) had objective improvement in their NPH symptoms after surgery. Of these, 27 patients (49%) developed delayed deterioration of at least one of their NPH symptoms, at a mean of 28.3 months postoperatively (range, 3-77). 1 of the 27 patients was found to have shunt malfunction; 19 had specific clinical or imaging evidence of shunt function. 6/19 patients had transient improvement in their symptoms (lasting 30 days or more) after adjustment of their programmable shunt valves (32%), although symptoms in all of these patients later worsened. During a mean follow up period of 44.4 months (range, 15-87), 12 patients (44%) received other neurological diagnoses felt to at least partially explain their symptoms. Increased patient age was associated with likelihood of delayed symptom progression. We conclude that delayed symptom progression is common after VPS placement for NPH, including after initial symptom improvement; that symptom progression can often be temporarily palliated by shunt valve pressure adjustment; and that older patients are more likely to experience delayed symptom progression. We suggest that patients and their families be counselled accordingly before surgery

Cell type‐specific regulatory sequences control expression of the Drosophila FMRF‐NH2 neuropeptide gene

The FMRFamide (dFMRFa) neuropeptide gene is expressed in about 17 diverse cell types in the Drosophila central nervous system. This expression pattern is generated by transcriptional control elements that are distributed over 8 kilobases of dFMRFa DNA. Previous studies identified one enhancer within the dFMRFa 5′ region that is both necessary and sufficient to drive reporter transgene expression in one of the 17 dFMRFa cell types, the OL2 neurons. We now report the presence of two additional, non‐overlapping enhancers within the gene: One drives expression by the six Tv neuroendocrine cells, and another in the four X and X2 interneurons. We also show that the Tv neuron‐specific enhancer itself has complex organization, with several positively and negatively acting cis elements. Together, these results describe the organization of what is likely to be a prototypic neuronal gene promoter: an assemblage of multiple, independent, cell type–specific enhancers, each consisting of multiple quantitative elements. © 1999 John Wiley & Sons, Inc. J Neurobiol 38: 507–520, 199

Correlation of factors predicting intraoperative brain shift with successful resection of malignant brain tumors using image-guided techniques

Intraoperative brain shift may cause inaccuracy of stereotactic image guidance on the basis of preoperatively acquired imaging data. The purpose of our study was to determine whether factors predicting brain shift affect the success of image-guided resection of malignant brain tumors. We retrospectively studied 54 patients who underwent image-guided resections of histopathologically confirmed malignant brain tumors (9 metastases, 45 high-grade gliomas). Precautions were taken during surgery to minimize brain shift, but intraoperative imaging was not performed. The following factors predictive of intraoperative brain shift were assessed: tumor size, periventricular location, patient age, prior surgery or radiation therapy, patient positioning, use of mannitol, and length of operative time. Postoperative magnetic resonance imaging was obtained in all cases within 48 hours of surgery to assess extent of resection. Perioperative mortality was 0% in our series; perioperative morbidity was 3 of 54 patients (5.5%); 1 patient required reoperation for a hematoma, and 2 had transient neurological deficits. Successful resection was accomplished in 93% of tumors less than 30 cm(3) compared with 63.6% of tumors greater than 30 cm(3) (P = .026, Fisher exact test). This difference was more pronounced for patients with malignant gliomas. However, other factors predictive of intraoperative brain shift were not associated with unsuccessful resection. Intraoperative brain shift does not significantly affect the likelihood of successful resection of malignant brain tumors smaller than 30 cm(3). Larger tumors are less likely to be successfully resected, although factors other than brain shift can contribute to unsuccessful resection

Pituicytoma presenting with spontaneous hemorrhage

Pituicytomas are rare tumors. Previously reported pituicytomas all presented with signs and symptoms relating to mass effect or endocrinological dysfunction. We report a 47 year old man who presented with sudden, severe headache and was found to have a hemorrhagic suprasellar mass with hemorrhage into the third ventricle. A mass arising from the pituitary stalk was found at surgery, and thorough pathological analysis revealed a pituicytoma. Pituicytoma should be considered in the differential diagnosis of a hemorrhagic suprasellar mass

Early Magnetic Resonance Imaging After Gamma Knife Radiosurgery of Brain Metastases

Gamma knife radiosurgery (GKRS) is often performed to treat brain metastases (BrMs). Widely referenced guidelines have suggested post-treatment imaging studies at 3-month intervals. However, clinicians frequently obtain magnetic resonance imaging (MRI) studies at <3 months after GKRS. We performed a retrospective medical record review study to assess the utility of early (<3 months) MRI after GKRS in patients with BrMs. A total of 415 GKRS procedures were performed. For 325 patients, early MRI studies were obtained. A total of 31 patients had new or worsened neurological symptoms. The early MRI studies showed adverse findings in 25 patients (78%), which in 23 (72%) had resulted in a change in treatment. For 294 patients, no new or worsened neurological symptoms were found on early MRI studies. Of these 294 patients, 86 (29%) had ≥1 adverse finding on MRI, and 60 (20%) had a change in management as a result. However, no rapidly growing tumors or other emergent adverse findings were seen. Early MRI (within 3 months) after post GKRS will frequently show adverse findings even in asymptomatic patients, more often in patients aged <65 years and patients with multiple treated BrMs. However, according to the nature of the adverse findings observed in our retrospective study, it is unlikely that the clinical outcomes would have been affected if the post-GKRS MRI studies had been deferred to 3 months after treatment. Our data support deferring post-GKRS MRI to 3 months after treatment in the absence of new neurological signs or symptoms

Yield and utility of routine postoperative imaging after resection of brain metastases

Magnetic resonance imaging (MRI) or computerized tomography (CT) is routinely performed after resection of brain metastases (BrM), regardless of whether there are specific clinical concerns about residual tumor or potential complications. Routine imaging studies contribute a significant amount to the cost of medical care, and their yield and utility are unknown. An IRB-approved retrospective chart review study was performed to analyze all craniotomies for BrM performed at our institution from 2005 to 2012. Descriptive statistics were used to quantify the yield of postoperative imaging. 218 consecutive patients underwent 226 craniotomies for BrM. In 21 cases, new or worsened neurologic deficits occurred after surgery (9.0%), and 19 of the 21 underwent postoperative imaging. 9 of the 19 patients (47%) had significant findings on postoperative imaging, and 2 patients required reoperation. 201 patients had no new neurologic deficits (91%), and 23 of these patients had no postoperative imaging. Of the 178 remaining patients, 160 underwent postoperative MRI and 18 underwent postoperative CT. 9 patients (5.1%) had unexpected adverse imaging findings; 6 had small stroke, 1 had a subdural hemorrhage and 2 had possible or definite venous sinus occlusion. None of the imaging findings led to changes in management. 182 patients underwent imaging appropriate to detect residual tumor (177 gadolinium enhanced MRI and 5 contrast enhanced CT). Of these patients, 16 were known to have small residual tumors based on intraoperative findings. Of the remaining 166 patients felt to have had gross total tumor resection, 9 (5.4%) were found to have a small amount of residual tumor on postoperative imaging; no patient had a change in treatment plan as a result. Routine postoperative imaging in patients undergoing craniotomy for BrM has a very low yield and may not be appropriate in the absence of new neurologic deficits, or specific clinical concerns about large amounts of residual tumor or intraoperative complications

Multifocal glioblastoma multiforme with synchronous spontaneous hemorrhage: case report

We report a 65 year old man who presented with left hemiparesis, and was found to have multiple, discrete, peripherally enhancing, hemorrhagic intra-axial masses in the right hemisphere of the brain. Workup for malignancy elsewhere in the body was negative, and biopsy confirmed glioblastoma multiforme. The patient responded clinically to treatment with radiation therapy and temozolomide. We discuss the unusual aspects of this case and stress the importance of tissue diagnosis in managing suspected intracranial malignancies

A novel technique for planning surgical approaches to the pineal region by using external cranial landmarks

The infratentorial supracerebellar approach to the pineal region presents special challenges during patient positioning. The head must be flexed and the body positioned to allow an operative trajectory under the straight sinus. Image guidance is not useful during positioning because registration and navigation take place after the head is fixed in its final position. Therefore, a reliable method of positioning based on external, easily identifiable landmarks to estimate the surgical trajectory along the straight sinus toward the pineal region is needed. Based on observation, the authors hypothesized that a line between 2 palpable external landmarks, the inion and the bregma, often approximates the surgical trajectory along the straight sinus. They tested this hypothesis by quantifying the relationship between the straight sinus and the bregma, and describe a method for estimating the working angle during patient positioning. The midsagittal, Gd-enhanced, T1-weighted MR images of 102 patients were analyzed. Demographic data and the presence or absence of tentorial pathological entities was recorded. The slant of the straight sinus was classified as common, high, or low, based on a previously described classification system. A line along the bottom of the straight sinus (that is, the straight-sinus line) was extended superiorly to its intersection with the calvaria, and the distance from this intersection point to the bregma was measured. The intersection point of the straight-sinus line and the calvaria was on average 2 ± 8.2 mm (these values are expressed as the mean ± SD throughout) anterior to the bregma (range 19.9 mm anterior to 19.1 mm posterior). The distance from the intersection point to the bregma was not statistically significantly different in younger or older patients, or in patients with or without tumors involving the pineal region. In patients with a low slant of the straight sinus, the intersection point was 5.3 ± 6.3 mm anterior to the bregma, whereas in patients with a high slant of the straight sinus, the intersection point was 0.21 ± 9.1 mm posterior to the bregma (p = 0.015). The straight-sinus line, which defines the working angle for the supracerebellar infratentorial approach, intersects the calvaria very close to the bregma in the majority of patients. Therefore, ideal patient positioning can be achieved by flexing the patient's head to optimize the working angle defined by an imaginary line connecting the torcula (inion) to the bregma