Neurosurgery Blog

Acta Neurochir (2010) 152:827–834. DOI 10.1007/s00701-009-0591-z

From a surgical perspective, tentorial fold (TF) meningiomas (TFM) are a unique entity of tumors. They involve the supra- and infratentorial space and often are in close contact to the cavernous sinus, cranial nerves, and the mesencephalon. Complete resection is challenging and can be hazardous. We present our experience with this rare tumor entity and demonstrate the surgical outcome related to a topographical classification.

Methods A retrospective analysis on 21 consecutive patients (female/male ratio 17/4) with meningiomas originating from the TF, who underwent surgery between 1992 and 2005 in our clinic, was performed. The follow-up period ranged from 6 to 93 months. The cases were classified according to tumor extension in three different types: type I, TF meningiomas with compression of the brain stem; type II, with extension into the anterior portion of middle fossa; and type III, a combination of type I and II. Depending on tumor location, surgical approaches consisted of pterional (nine cases), subtemporal (nine cases), or combined subtemporal–pterional craniotomies (three cases). We defined transient and persistent operative complications in relation to Simpson grade and TF classification.

Results Tumor size ranged from 1 to 6 cm in diameter, with a median at 2.5 cm. The presenting symptoms of the patients were anisocoria (six cases), diplopia (six cases), ptosis (five cases), hemianopia (four cases), and ataxia (two cases). Extent of tumor resection was Simpson grade II in 19 patients, grade III in one patient, and grade IV in one patient. There was no operative mortality (first 30 days after surgery). The rate of postoperative transient new neurological deficits was found at 9.5%, the rate of permanent at 33%. The neurological deficits at admission recovered in two patients.

Conclusion In the majority of patients with TF meningiomas, total resection can be achieved through a pterional, subtemporal, or combined approaches but at a substantial toll in terms of permanent morbidity. Radiotherapy after volume reductive surgery in TFM type II and III and decompression of eloquent anatomical structures with low tolerance of radiation should be considered.

J Neurosurg 112:1033–1038, 2010. (DOI: 10.3171/2009.6.JNS08132)

The authors used a fiber dissection technique to describe the temporal stem and explain the tendency of malignant tumors to spread within both the frontal and temporal lobes. The authors focused on the morphological characteristics and course of various fasciculi of the temporal stem, including the uncinate fascicle, occipitofrontal fascicle, anterior commissure, loop of the optic radiations (Meyer loop), and the ansa peduncularis.

Methods. Eight previously frozen, formalin-fixed human brains were dissected under an operating microscope using the fiber dissection technique described by Klingler. Lateral, inferior, and medial approaches were made. Crosssectional 3D MR images obtained in 10 patients without brain lesions demonstrated that fibers of the temporal stem, which were intermingled together in various ways, curved laterally within the basal forebrain. Various pathological entities affecting the temporal stem are described and discussed.

Results. The uncinate fascicle has 3 portions: a ventral extension, an intermediary segment called the isthmus, and a dorsal segment. The inferior occipitofrontal fasciculus is a layer of more superficial white matter that appeared to be superior to the uncinate fasciculus. A short ventral portion of the radiations of the corpus callosum was sometimes noted to run ventrally to enter the temporal stem and to reach both temporal lobes.

Conclusions. To the authors’ knowledge, a detailed anatomy of the temporal stem has not been previously described in the literature. The unique anatomy of the temporal stem provides a route for tumor spread between the frontal and temporal lobes.

Acta Neurochir (2010) 152:749–761.DOI 10.1007/s00701-009-0595-8

Pituitary apoplexy is a rare and life-threatening complication occurring in 0.6–10.5% of all cases of pituitary adenomas. Although the association between pituitary apoplexy and visual dysfunction has been recognized for a long time, the optimal management of this problem still remains controversial. The purpose of this overview was to present the surgical experience by analyzing the literature on the management of pituitary apoplexy for better treatment of these cases.

Materials and method To establish a new guideline for the surgical treatment of this entity, publications reported during the last century and databases containing medical literature were analyzed. In addition, an illustrative case with pituitary apoplexy presenting with complaints of sudden onset severe headache associated with nausea, vomiting, and a sudden loss of vision was described. In fact, the experience in our complicated patient prompted us to review the available literature on the management of pituitary apoplexy to date.

Conclusions Based on an overview of 186 cases of apoplectic pituitary adenoma presenting with monocular or binocular blindness, we highlight the importance of correct diagnosis and an early, but not necessarily emergency, surgery within the first week of admission to optimize visual outcome of such patients. The illustrative case further exemplifies the value of close interaction between members of the management team for optimal outcome.

Neurosurgery 66:978-985, 2010 DOI: 10.1227/01.NEU.0000368108.94233.22

Identification and complete interruption of fistulae are essential but not always obvious during the surgical treatment of spinal dural arteriovenous fistulae (dAVFs). We examined cases in which we identified and confirmed surgical obliteration of a spinal dAVF with the aid of microscope-integrated near-infrared indocyanine green (ICG) videoangiography.

METHODS: ICG videoangiography was performed during 6 surgical interventions in which 6 intradural dorsal AVFs (type I) were interrupted. An operating microscope-integrated light source containing infrared excitation light illuminated the operating field and was used to visualize an intravenous bolus of ICG. The locations of fistulae, feeding arteries, and draining veins and documentation of occlusion of the fistulae were compared with findings on preoperative and postoperative digital subtraction angiography.

RESULTS: ICG videoangiography identified the fistulous point(s), feeding arteries, and draining veins in all 6 cases, as confirmed by immediate postoperative selective spinal angiography. In 1 case, intraoperative ICG ruled out an additional questionable fistula at a contiguous level suspected on the preoperative angiography.

CONCLUSION:Microscope-based ICG videoangiography is simple and provides real-time information about the precise location of spinal dAVFs. During spinal dAVF surgery, this technique can be useful as an independent form of angiography or as an adjunct to intraor postoperative digital subtraction angiography. Larger series are needed to determine whether use of this modality could reduce the need for immediate postoperative spinal angiography after obliteration of intradural dorsal AVFs.

J Neurosurg Pediatrics 5:474-478, 2010. DOI: 10.3171/2010.1.PEDS09218

The optimal surgical management of Chiari malformation (CM) is evolving. Evidence continues to accrue that supports decompression without duraplasty as an effective treatment to achieve symptomatic relief and anatomical decompression. The risks and benefits of this less invasive operation need to be weighed against decompression with duraplasty.

Methods. The authors performed a retrospective review of all CM decompressions from 2003 to 2007. All operations were performed by a single surgeon at a single institution. Data were analyzed for outcome, postoperative morbidity, and recurrence.

Results. Of 121 unique patients, 56 underwent posterior fossa decompressions without duraplasty (PFD) and 64 patients underwent posterior fossa decompressions with duraplasty (PFDD). Of the 56 PFD patients, 7 (12.5%) needed a subsequent PFDD for symptomatic recurrence. Of the 64 patients who underwent a PFDD, 2 (3.1%) needed a repeated PFDD for symptomatic recurrence. Patients treated with PFDD had an average operative time of 201 minutes in contrast to 127 minutes for those who underwent PFD (p = 0.0001). Patients treated with PFDD had average hospital stays of 4.0 days, whereas that for patients treated with PFD was 2.7 days (p = 0.0001). While in the hospital, patients treated with PFDD used low-grade narcotics, intravenous narcotics, muscle relaxants, and antiemetic medications at statistically significant differing rates.

Conclusions. While PFD was associated with a higher rate of recurrent symptoms requiring repeated decompression, this may be justified by the significantly lower morbidity rate. Clearer delineation of the trade-off between morbidity and recurrence may be used to help patients and their families make decisions regarding care.

Neurosurgery. 66(5):999-1004, May 2010. DOI: 10.1227/01.NEU.0000368443.43565.2A

Advances in medicine have largely followed advances in technology. Medical strides have been made when physicians and researchers have adapted growing science to target specific problems. A new medical field, telemedicine, has emerged that links physicians with colleagues and patients. Cell phone technology is affordable for almost everyone, and basic models include digital photography.

OBJECTIVE: We present a case series exhibiting the utility of digital pictures taken with patients’ cell phones.

CLINICAL PRESENTATION: Our patients had wound infections requiring daily intravenous antibiotics and dressing changes. Previously, these patients would have required prolonged hospitalizations. Currently, patients with these infections are discharged from the hospital, but close outpatient observation is required to monitor the wound. Our patients lived up to 8 hours away from the hospital. Daily appointments for wound checks in the clinic were impractical. Wounds were monitored via cell phone images without the inconvenience of travel and the expense of a local hotel, and unnecessary appointments in the clinic.

INTERVENTION: Wound evaluations were conducted with the patients’ cell phone cameras. These images were transmitted to the surgeon by text messaging and emails.

CONCLUSION: This application of cell phone technology has been documented in other literature and could become a legitimate method for close outpatient observation by neurosurgeons if medicolegal issues are addressed.

J Neurosurg 112:951–956, 2010. DOI: 10.3171/2009.8.JNS09703

Stereotactic radiosurgery (SRS) has proven to be a safe and effective treatment for many patients with intracranial meningiomas. Nevertheless, the morbidity associated with radiosurgery of larger meningiomas is poorly understood.

Methods. The authors performed a retrospective review of 116 patients who underwent SRS for meningiomas (WHO Grade I) > 10 cm3 between 1990 and 2007, with a minimum follow-up of 12 months. Patients with atypical or malignant meningiomas and those who received prior radiotherapy were excluded. The average tumor volume was 17.5 cm3 (range 10.1–48.6 cm3); the average tumor margin dose was 15.1 Gy (range 12–18 Gy); and the mean follow-up duration was 70.1 months (range 12–199 months).

Results. Tumor control was 99% at 3 years and 92% at 7 years after radiosurgery. Thirty complications after radiosurgery were noted in 27 patients (23%), including 7 cases of seizures, 6 cases of hemiparesis, 5 cases of trigeminal injury, 4 cases of headaches, 3 cases of diplopia, 2 cases each of cerebral infarction and ataxia, and 1 case of hearing loss. Patients with supratentorial tumors experienced a higher complication rate compared with patients with skull base tumors (44% compared with 18%) (hazard ratio 2.9, 95% CI 1.3–6.7, p = 0.01).

Conclusions. The morbidity associated with SRS for patients with benign meningiomas > 10 cm3 is greater for supratentorial tumors compared with skull base tumors. Whereas radiosurgery is relatively safe for patients with large-volume skull base meningiomas, resection should remain the primary disease management for the majority of patients with large-volume supratentorial meningiomas.

J Spinal Disord Tech 2010;23:157–161

Study Design/Setting: Retrospective review of clinical outcomes after anterior cervical discectomy and fusion (ACDF) surgery with allograft and plating in patients over 55 years of age.

Objective: To evaluate the results of ACDF surgery in patients aged 55 years and older.

Summary of Background Data: ACDF surgery has been a standard treatment for cervical degenerative and herniated disc disease for many years. Previous assessments of efficacy have used patient perceived outcome measures including the Neck Disability Index (NDI) and the Short Form 36 Question Health Questionnaire (SF-36). Patient perceived outcome after ACDF surgery in an age specific cohort (55 y and older) has not been documented previously.

Methods: Fifty-two consecutive patients over 55 years of age who underwent 1 to 3 level ACDF with allograft and plating were identified. Patient perceived outcome questionnaires (NDI and SF-36) were available for 44 patients. There were 28 females and 16 males. Mean age at time of surgery was 61.8 years. Average length of follow-up was 25.2 months (12 to 54 mo).

Results: All but one patient demonstrated radiographic healing of the fusion site at the time of their last follow-up. The mean improvement of these 10 groups (total NDI score) was statistically significant (difference = 9.47, t=5.6390, P=1.5198E-06). There was a statistically significant decrease in disability in 7 of the 8 SF-36 categories as well. The mean of the 8 SF-36 categories (total SF-36) improved significantly (improvement=11.92, t= 3.6857, P=0.0007).

Conclusions: On the basis of our statistically significant improvement in NDI and SF-36 scores, as a measure of patient perceived outcome after ACDF surgery, outcomes after ACDF surgery in patients over 55 years of age are not significantly different than those of a younger patient population

Childs Nerv Syst (2010) 26:681–687.DOI 10.1007/s00381-009-1039-8

The purpose of this study was to review our experience with a multimodality treatment approach in the management of cerebral arteriovenous malformation (AVM) in children.

Methods We retrospectively analysed a consecutive series of 56 children who harboured a cerebral AVM and were treated at our institution between 1988 and 2008. During the whole treatment period, a combined treatment strategy, including microsurgery, endovascular treatment and gamma knife radiosurgery, was used.

Results Of the 56 patients (median age, 14.0; range, 3 months–18 years) reported, 36 (64.3%) were admitted after AVM rupture; of these, only one AVM (1.8%) was considered untreatable. In 30.9% (17/55) of the treated patients, a single treatment measure was sufficient to attain angiographic cure of the AVM. Among these, six patients (10.9%) had microsurgical AVM resection, four patients (7.3%) underwent endovascular treatment, and another seven patients (12.7%) underwent radiosurgical management of the AVM. The majority of the population (38/55; 69.1%) underwent combined treatment: 21 patients (38.2%) received embolisation followed by radiosurgery of the remnant nidus, ten patients (18.2%) underwent embolisation with subsequent surgical resection of the residual AVM, three patients (5.5%) had radiosurgery after incomplete surgical AVM nidus resection and another four patients (7.3%) required a combination of all three treatment modalities to achieve permanent angiographic cure of the AVM. We observed good clinical outcomes (Glasgow Outcome Scale 5 and 4) in 94.6% of the children. Complete angiographic obliteration was achieved in 93.3% of the patients treated.

Conclusion A multimodality treatment approach in children harbouring cerebral AVMs leads to excellent angiographic and clinical outcomes.

J Neurosurg 112:1061–1069, 2010. DOI: 10.3171/2009.7.JNS081504

Transcranial approaches to clival chordomas provide a circuitous route to the site of origin of the tumor often involving extensive bone drilling and brain retraction, which places critical neurovascular structures between the surgeon and pathology. For certain chordomas, the endonasal endoscopic transclival approach is a novel minimal access, but it is an equally aggressive alternative providing the most direct route to the tumor epicenter.

Methods. The authors present a consecutive series of patients undergoing endonasal endoscopic resection of clival chordomas. Extent of resection was determined by postoperative volumetric MR imaging and divided into > 95% and < 95%.

Results. Seven patients underwent 10 operations. Preoperative cranial neuropathies were present in 4. The mean patient age was 52.0 years. The mean tumor volume was 34.9 cm3. Intraoperative lumbar drainage was used in 1 patient, and the tumors extended intradurally in 3. One patient underwent 2 intentionally palliative procedures for subtotal debulking. Greater than 95% resection was achieved in 7 of 8 operations in which radical resection was the goal (87%). All tumors with volumes < 50 cm3 had > 95% resection (p = 0.05). The overall mean follow-up was 18.0 months. Cranial neuropathies resolved in all 3 patients with cranial nerve VI palsies. One patient with recurrent nasopharyngeal chordoma died of disease progression; another experienced 2 recurrences before receiving radiation therapy. All surviving patients remain progression free. There were no intraoperative complications; however, 1 patient developed a pulmonary embolus postoperatively. There were no postoperative CSF leaks.

Conclusions. The endonasal endoscopic transclival approach represents a less invasive and more direct approach than a transcranial approach to treat certain moderate-sized midline skull base chordomas. Longer follow-up is necessary to determine comparability to transcranial approaches for long-term control. Large tumors with significant extension lateral to the carotid artery may not be suitable for this approach.

Spine 2010;35:1136–1143

Use of magnetic resonance imaging (MRI) with Constructive Interference in Steady State (CISS) sequence and isometric voxels to demonstrate the anatomic variations of vertebral artery in C2 vertebra. Objectives. To determine the transarticular screw trajectory on CISS MRI and to identify patients with anatomic variations of vertebral artery in C2 vertebra. Summary of Background Data. Atlantoaxial transarticular screw fixation has been reported to be biomechanically superior to other posterior techniques for atlantoaxial arthrodesis. Vertebral artery injury can be associated with catastrophic sequelae. Anatomic variation of vertebral artery is well recognized and computed tomography scan is the traditional preoperative assessment. However, no report has evaluated the use of MRI in preoperative assessment for the screw trajectories and the anatomic variation of vertebral artery. Methods. The 3-dimensional (3D) CISS MRI with isometric voxels was performed in 30 local Chinese patients. The 3D reconstruction images were created to determine the proposed screw trajectories and their relationship with the vertebral arteries. Results. In 12 patients (40%), the vertebral arteries were lying within the screw trajectories prohibiting transarticular screw fixation on at least one side. Bilateral variations with high risk of vertebral artery injuries were found in 6 patients. The remaining 6 patients had unilateral variations prohibiting the insertion of transarticular screws on one side. Conclusion. The 3D CISS MRI with isometric voxels is a safe and simple imaging technique to outline the vertebral arteries in C2. Reconstruction images are easily created and undistorted. It is one of the useful imaging in preoperative planning of transarticular screw fixation and determination of anatomy of vertebral artery.

J Neurosurg 112:1020–1032, 2010. DOI: 10.3171/2009.7.JNS09758

The aim of this study was to answer the question whether quality of life and progression-free and overall survival are increased in adults with supratentorial malignant glioma who are treated with cytoreductive resection as compared with those who only undergo biopsy.

Methods. A literature search of the electronic databases MEDLINE, EMBASE, and CENTRAL was performed to identify relevant studies published before May 2008. Hand-searching of reference lists of the identified studies and relevant review articles was also performed. A study was considered eligible, regardless of study design (prospective or retrospective), if: 1) quality of life and/or progression-free and/or overall survival was compared among adult patients undergoing biopsy or resection, and 2) patient age and Karnofsky Performance Scale scores were not significantly different among the 2 groups compared.

Results. One randomized controlled trial and 4 retrospective studies (involving a total of 1111 patients) were found eligible for this systematic review. A meta-analysis of the eligible studies demonstrated a significant increase in overall survival in the patients treated with resection instead of biopsy (hazard ratio 0.61, 95% CI 0.52–0.71, p < 0.0001, fixed-effect model). Although statistical pooling was not feasible, the available data suggest that quality of life was increased in patients treated with resection rather than biopsy, while there did not seem to be any significant difference in progression-free survival between the 2 groups.

Conclusions. Based on the best available evidence, it appears that cytoreductive resection in adults with supratentorial malignant glioma is associated with improved overall survival as compared with biopsy. However, well designed prospective studies are needed for more solid conclusions to be drawn.

Neurosurgery 66:1005-1012, 2010 DOI: 10.1227/01.NEU.0000367721.73220.C9

Gross total resection of intradural spinal tumors can be achieved in the majority of cases with preservation of long-term neurological function. However, postoperative progressive spinal deformity complicates outcome in a subset of patients after surgery. We set out to determine whether the use of laminoplasty (LP) vs laminectomy (LM) has reduced the incidence of subsequent spinal deformity following intradural tumor resection at our institution.

METHODS:We retrospectively reviewed the records of 238 consecutive patients undergoing resection of intradural tumor at a single institution. The incidence of subsequent progressive kyphosis or scoliosis, perioperative morbidity, and neurological outcome were compared between the LP and LM cohorts.

RESULTS: One hundred eighty patients underwent LM and 58 underwent LP. Patients were 46 ± 19 years old with median modified McCormick score of 2. Tumors were intramedullary in 102 (43%) and extramedullary in 102 (43%). All baseline clinical, radiographic, and operative variables were similar between the LP and LM cohorts. LP was associated with a decreased mean length of hospitalization (5 vs 7 days; P = .002) and trend of decreased incisional cerebrospinal fluid leak (3% vs 9%; P = .14). Following LP vs LM, 5 (9%) vs 21 (12%) patients developed progressive deformity (P = .728) a mean of 14 months after surgery. The incidence of progressive deformity was also similar between LP vs LM in pediatric patients < 18 years of age (43% vs 36%), with preoperative scoliosis or loss of cervical/lumbar lordosis (28% vs 22%), or with intramedullary tumors (11% vs 11%).

CONCLUSION: LP for the resection of intradural spinal tumors was not associated with a decreased incidence of short-term progressive spinal deformity or improved neurological function. However, LP may be associated with a reduction in incisional cerebrospinal fluid leak. Longer-term follow-up is warranted to definitively assess the long-term effect of LP and the risk of deformity over time.

J Neurosurg 112:997–1004, 2010. DOI: 10.3171/2009.9.JNS09805

Glioblastoma multiforme (GBM) is the most common and aggressive type of primary brain tumor in adults. Although the average survival is ~ 12 months, individual survival is heterogeneous. The ability to predict short- and long-term survivors is limited. Therefore, the aims of this study were to ascertain preoperative risk factors associated with survival, develop a preoperative prognostic grading system, and evaluate the utility of this grading system in predicting survival for patients undergoing resection of a primary intracranial GBM.

Methods. Cases involving adult patients who underwent surgery for an intracranial primary (de novo) GBM between 1997 and 2007 at The Johns Hopkins Hospital, an academic tertiary-care institution, were retrospectively reviewed. Multivariate proportional hazards regression analysis was used to identify preoperative factors associated with survival, after controlling for extent of resection and adjuvant therapies. The identified associations with survival were then used to develop a grading system based on preoperative variables. Survival as a function of time was plotted using the Kaplan-Meier method, and survival rates were compared using Log-rank analysis. Associations with p < 0.05 were considered statistically significant.

Results. Of the 393 patients in this study, 310 (79%) had died as of most recent follow-up (median time from surgery to death 11.9 months). The preoperative factors, independent of extent of resection and adjuvant therapies (carmustine wafers, temozolomide, and radiation), found to be negatively associated with survival were: age > 60 years (p < 0.0001), Karnofsky performance status score ≤ 80 (p < 0.0001), motor deficit (p = 0.02), language deficit (p = 0.001), and periventricular tumor location (p = 0.04). Patients possessing 0–1, 2, 3, and 4–5 of these variables were assigned a preoperative grade of 1, 2, 3, and 4, respectively. Patients with a preoperative grade of 1, 2, 3, and 4 had a median survival of 16.6, 10.2, 6.8, and 6.1 months, respectively.

Conclusions. The present study found that older age, poor performance status, motor deficit, language deficit, and periventricular tumor location independently predicted poorer survival in patients undergoing GBM resection. A grading system based on these factors was able to identify 4 distinct groups of patients with different survival rates. This grading system, based only on preoperative variables, may provide patients and physicians with prognostic information that may guide medical and surgical therapy before any intervention is pursued

J Neurosurg 112:907–912, 2010. DOI: 10.3171/2009.6.JNS09120

Resecting large meningiomas along the posterior fossa convexity or cerebellopontine angle (CPA) through a suboccipital approach can be challenging. Limitations include a restricted angle of view, high venous pressures, and suboptimal brain relaxation. While a far-lateral craniotomy is a viable alternative, the risks associated with condylar resection are undesirable.

Methods. The authors retrospectively evaluated a modified far-lateral approach in a consecutive series of 12 patients with large or giant posterior fossa convexity and CPA meningiomas. This approach incorporates transversesigmoid sinus exposure and C-1 laminectomy, but there is no condylar resection.

Results. Between January 2006 and February 2008, 12 patients (mean age 52 years) presented with large or giant meningiomas of the posterior fossa convexity or CPA. The mean tumor volume was 72.6 cm3 (range 8–131 cm3). Signs and symptoms at presentation included headache (in 8 patients), cranial neuropathy (in 4), and progressive hemiparesis (in 4). There were no operative complications, and the majority of patients (9) had Simpson Grade I or II resections. There were no new permanent neurological deficits following resection, although 2 patients (17%) had transient deficits. The mean modified Rankin score decreased from 2.2 preoperatively to 0.6 postoperatively.

Conclusions. A modified far-lateral approach to the posterior fossa and CPA allows for safe, and often total, resection of large meningiomas with minimal morbidity. While avoiding the risks of condylar resection, this microsurgical strategy allows for greater field of view, minimal venous bleeding, and immediate access to the spinal subarachnoid space.

Neurosurgery 66:917-924, 2010 DOI: 10.1227/01.NEU.0000367801.35654.EC

Diffusion tensor imaging (DTI) parameters were investigated in patients with chronic idiopathic hydrocephalus to evaluate microstructural changes of brain tissue caused by chronic ventricular dilatation.

METHODS: Eleven patients fulfilling the criteria for possible or probable idiopathic normal pressure hydrocephalus and 10 healthy control subjects underwent MRI at 3 Tesla, including DTI with 12 gradient directions. Patients were scanned before lumbar cerebrospinal fluid (CSF) withdrawal tests. Differences in fractional anisotropy (FA) and mean diffusivity (MD) between patients and controls were assessed using 2 different methods: manual definition of regions of interest and a fully automated method, TBSS (Tract-Based Spatial Statistics). DTI parameters were correlated with clinical findings.

RESULTS: Compared with the control group, patients with chronic idiopathic hydrocephalus had significantly higher MD values in both the periventricular corticospinal tract (CST) and the corpus callosum (CC), whereas FA values were significantly higher in the CST but lower in the CC. DTI parameters of the CST correlated with the severity of gait disturbances.

CONCLUSION:Microstructural changes in periventricular functionally relevant white matter structures (CSF, CC) in chronic idiopathic hydrocephalus can be visualized using DTI. Further studies should investigate the change of DTI parameters after CSF shunting and its relation to neurologic outcome.

Neurosurgery 66:904-909, 2010 DOI: 10.1227/01.NEU.0000368385.74625.96

This study investigated the outcome of early shunt placement in patients with poor-grade subarachnoid hemorrhage and the effect of intraventricular hemorrhage (IVH) and high proteinaceous cerebrospinal fluid (CSF) on subsequent shunt performance. METHODS:This study included 33 consecutive patients with initial Fisher grade (3/4) subarachnoid hemorrhage who had undergone conversion from external ventricular drainage (EVD) to a ventriculoperitoneal (VP) shunt and whose computed tomography scan showed IVH at the time of shunt placement. Early weaning from an EVD and conversion to a VP shunt was performed irrespective of IVH or high protein content in the CSF. RESULTS: The mean interval from EVD to VP shunt placement was 6.4 days. The mean volume of IVH was 9.44 mL, and the mean value of IVH/whole ventricle volume ratio (ie, percentage of blood suspension in the CSF) was 9.81%. The mean perioperative protein level in the CSF was 149 mg/dL. During the follow-up period, 2 patients (6.1%) required VP shunt placement, and no patients experienced complications of ventriculitis or shunt-related infection. CONCLUSION: Based on our data, earlier EVD weaning and shunt placement can effectively treat subarachnoid hemorrhage–induced hydrocephalus in patients with severe subarachnoid hemorrhage. This procedure resulted in no shunt-related infections and a 6.1% revision rate. There were fewer adverse effects of IVH and protein on shunt performance. Therefore, weaning from an EVD and conversion to a permanent VP shunt need not be delayed because of IVH or proteinaceous CSF.

Neurosurgery 66:883-892, 2010 DOI: 10.1227/01.NEU.0000368395.82329.C4

The anterior skull base, in front of the sphenoid sinus, can be approached using a variety of techniques including extended subfrontal, transfacial, and craniofacial approaches. These methods include risks of brain retraction, contusion, cerebrospinal fluid leak, meningitis, and cosmetic deformity. An alternate and more direct approach is the endonasal, transethmoidal, transcribriform, transfovea ethmoidalis approach.

METHODS: An endoscopic, endonasal approach was used to treat a variety of conditions of the anterior skull base arising in front of the sphenoid sinus and between the orbits in a series of 44 patients. A prospective database was used to detail the corridor of approach, closure technique, use of intraoperative lumbar drainage, operative time, and postoperative complications. Extent of resection was determined by a radiologist using volumetric analysis.

RESULTS: Pathology included meningo/encephaloceles (19), benign tumors (14), malignant tumors (9), and infectious lesions (2). Lumbar drains were placed intraoperatively in 20 patients. The CSF leak rate was 6.8% for the whole series and 9% for intradural cases. Leaks were effectively managed with lumbar drainage. Early reoperation for cerebrospinal fluid (CSF) leak occurred in 1 patient (2.2%). There were no intracranial infections. Greater than 98% resection was achieved in 12 of 14 benign and 5 of 9 malignant tumors.

CONCLUSION: The endoscopic, endonasal, transethmoidal, transcribriform, transfovea ethmoidalis approach is versatile and suitable for managing a variety of pathological entities. This minimal access surgery is a feasible alternative to transcranial, transfacial, or combined craniofacial approaches to the anterior skull base and anterior cranial fossa in front of the sphenoid sinus. The risk of CSF leak and infection are reasonably low and decrease with experience. Longer follow-up and larger series of patients will be required to validate the long-term efficacy of this minimally invasive approach.

Acta Neurochir (2010) 152:817–825. DOI 10.1007/s00701-009-0588-7

Surgical outcome after microvascular decompression (MVD) for primary trigeminal neuralgia (TN) has been demonstrated as being related to the characteristics of the neurovascular compression (NVC), especially to the degree of compression exerted on the root. Therefore, preoperative determination of the NVC features could be of great value to the neurosurgeon, for evaluation of conflicting nature, exact localization, direction and degree of compression. This study deals with the predictive value of MRI in detecting and assessing features of vascular compression in 100 consecutive patients who underwent MVD for TN.

Methods. The study included 100 consecutive patients with primary TN who were submitted to a preoperative 3D MRI 1.5 T with T2 high-resolution, TOF-MRA, and T1-Gadolinium. Image analysis was performed by an independent observer blinded to the operative findings and compared with surgical data.

Findings. In 88 cases, image analysis showed NVC features that coincided with surgical findings. There were no false-positive results. Among 12 patients that did not show NVC at image analysis, nine did not have NVC at intraoperative observation, resulting in three false-negative cases. MRI sensitivity was 96.7% (88/91) and specificity 100% (9/9). Image analysis correctly identified compressible vessel in 80 of the 91 cases and degree of compression in 77 of the 91 cases. Kappa-coefficient predicting degree of root compression was 0.746, 0.767, and 0.86, respectively, for Grades I (simple contact), II (distortion), and III (marked indentation; p<0.01).

Conclusion. 3D T2 high-resolution in combination with 3D TOF-MRA and 3D T1-Gadolinium proved to be reliable in detecting NVC and in predicting the degree of the root compression