'What's in a name', a systematic review of the pterional craniotomy for aneurysm surgery and its many modifications with a proposal for simplified nomenclature

BACKGROUND

The pterional or frontosphenotemporal craniotomy has stood the test of time and continues to be a commonly used method of managing a variety of neurosurgical pathology. Already described in the beginning of the twentieth century and perfected by Yasargil in the 1970s, it has seen many modifications. These modifications have been a normal evolution for most neurosurgeons, tailoring the craniotomy to the patients' specific anatomy and pathology. Nonetheless, an abundance of variations have appeared in the literature.

METHODS

A search strategy was devised according to the 2020 Preferred Reporting Items of Systematic Reviews and Meta-Analyses (PRISMA) statement. To identify articles investigating the variations in the pterional approach, the following search terms were applied: (pterional OR minipterional OR supraorbital) AND (approach OR craniotomy OR technique).

RESULTS

In total, 3552 articles were screened with 74 articles being read in full with 47 articles being included for review. Each article was examined according the name of the technique, temporalis dissection technique, craniotomy technique and approach.

CONCLUSION

This systematic review gives an overview of the different techniques and modifications to the pterional craniotomy since it was initially described. We advocate for the use of a more standardised nomenclature that focuses on the target zone to simplify the management approach to supratentorial aneurysms.

Non-programmable shunts for communicating hydrocephalus and 3D volumetry: a retrospective analysis

OBJECTIVE

Although the use of different types of valves have been extensively studied in shunt surgeries for communicating hydrocephalus (cHC), a consensus about the valve type remains absent. The objective of this study is to evaluate our results with the primary placement of non-programmable valves (NPV) for this indication.

METHODS

We retrospectively analyzed all first NPV implanted between 2014-2020 for cHC. We studied the revision rate, clinical outcome described by modified Ranking Scale (mRS) and radiological evolution using Evans index (EI) and ventricular volumes 3D-semiautomatic segmentation (vv-3DSAS).

RESULTS

Forty-one patients were shunted for post-hemorrhagic (61%), post-traumatic (24.4%) and tumoral (14.6%) hydrocephalus (HC). Mean age was 65 years (range 25-89yrs). Overall, 59 procedures were performed including 18 revision surgeries in 12 patients (29.3%). Underlying reason for first shunt revision were valve type related: valve dysfunction, overdrainage, underdrainage and non-valve type related: malpositioning, infection, shunt migration. The shunt-related revision rate was 17.1%. Twenty-eight patients (68.3%) had an mRS improvement of 1 or more points. We found a good correlation between ventricle volumes (VV) and EI and a significant reduction in VV measured by EI and vv-3DSAS was observed. However, the mRS improvement was not correlated with a reduction of ventricle volumes.

CONCLUSION

Overall, our results in terms of shunt revisions as well as clinical and radiological evolution are comparable with the literature for NPV. vv-3DSAS can be used and could be useful to detect small changes in VV in patients with cHC.

Randomized Trial Comparing Burr Hole Craniostomy, Minicraniotomy, and Twist Drill Craniostomy for Treatment of Chronic Subdural Hematoma

BACKGROUND

The mainstay of treatment for symptomatic or large chronic subdural hematoma (CSDH) is surgery, but controversy still exists regarding the best surgical technique. Three different techniques are commonly used: burr hole craniostomy (BHC), minicraniotomy (MC), and twist drill craniostomy (TDC).

OBJECTIVE

To determine which surgical technique for drainage of CSDH offers best results.

METHODS

We set up a multicenter prospective randomized trial (Comparison of Chronic Subdural Hematoma Treatment [COMPACT] trial) comparing BHC, MC, and TDC for the surgical treatment of CSDH. The primary end point was reoperation rate, and secondary end points included complication rates and clinical outcome. Patients were considered to have good outcome when they did not undergo reoperation, suffered no surgical or medical complication, and had no related mortality. Clinical outcome was also evaluated by evolution of the Markwalder score and the modified Rankin score.

RESULTS

Two-hundred forty-five patients were included in the final analysis: 79 BHC, 84 MC, and 82 TDC. Mean duration of surgery was shorter for TDC than for BHC and MC (P < .001). Reoperation rate was 7.6% for BHC, 13.1% for MC, and 19.5% for TDC (P = .07). This trend toward better results for BHC was not statistically significant in logistic regression analysis. The proportion of patients with good outcome was 78.5% for BHC group, 76.2% for MC, and 69.5% for TDC (P = .4). Evolution of the Markwalder score and modified Rankin score were not significantly different between treatment groups.

CONCLUSION

All 3 techniques are effective at treating patients with CSDH with eventual 6-month outcome being similar. Although not reaching statistical significance in our study, BHC offers the lowest recurrence rate combined with manageable complication rate.

Cumulative surgical morbidity in patients with multiple cerebellar and medullary hemangioblastomas

OBJECTIVE

Patients affected with von Hippel-Lindau disease often develop multiple hemangioblastomas in the cerebellum and spinal cord. Timing of surgical intervention is difficult and depends largely on the anticipated surgical morbidity. However, data regarding surgical outcome after multiple cerebellar and medullary surgeries are scarce. Our objective was to evaluate cumulative surgical morbidity in patients operated on multiple cerebellar and medullary hemangioblastomas and to deduce recommendations for treatment.

METHODS

We performed a retrospective analysis for a consecutive cohort of von Hippel-Lindau patients with surgical treatment of at least two cerebellar and/or medullary hemangioblastomas. Pre- and postoperative functional grades were reviewed in patients' files and compared by Modified Ranking Scale (cerebellar surgeries) or by Modified McCormick Score (medullary surgeries).

RESULTS

Thirty-six patients were surgically treated for at least two cerebellar hemangioblastomas (12 patients), at least two medullary hemangioblastomas (19 patients) or at least two hemangioblastomas in both locations (5 patients). Fourthy-eight cerebellar and 80 medullary procedures were performed in total. On average, multiple cerebellar surgeries caused no clinical deterioration, whereas multiple medullary surgeries led to a slight cumulative deterioration of postoperative functional grades. The severity of this deterioration did not correlate to the number of performed medullary surgeries.

CONCLUSION

Resection of multiple cerebellar hemangioblastomas is not associated with cumulative morbidity. Although there is a certain cumulative surgical morbidity caused by medullary surgeries, its extent does not increase with the number of performed surgeries. Microsurgical removal of asymptomatic tumors with radiographic progression can also be considered for patients with multiple tumors and previous surgeries.

Predictors of dopamine agonist resistance in prolactinoma patients

BACKGROUND

Surgical resection of prolactinomas resistant to dopamine agonists is frequently incomplete due to fibrotic changes of the tumour under pharmacological therapy. In order to identify a subgroup of patients who may benefit from early surgery, we thought to investigate possible predictive factors of pharmacological resistance of prolactinomas to dopamine agonists.

METHODS

We retrospectively analyzed a database of a Belgian tertiary reference center for patients with pituitary tumours from 2014 to 2016. The groups of interest were patients with dopamine agonist responsive and resistant prolactinomas. The possible predictive factors, including MRI findings, endocrinological parameters, response of tumour and patient factors for dopamine agonist resistance were investigated.

RESULTS

We included 69 patients of whom 52 were women (75,4%) and 17 were men (24,6%). Rate of dopamine agonist resistance was 15.9%. We identified four significant predictors of dopamine agonist resistance: male gender, a large tumour volume, prolonged time to prolactin normalization and presence of a cystic, hemorrhagic and/or necrotic component. In addition, symptoms due to mass effect, high baseline prolactin level and a high contrast capture on MRI are factors that can be taken into consideration.

CONCLUSION

We identified predictive factors for pharmacological resistance and developed a scoring system for patient specific prediction of resistance to dopamine agonists. This scoring system may have impact on the timing and decision of surgery in prolactinoma patients after further prospective evaluation.

SCIDOT-30. GLITIPNI: A PHASE 1B CLINICAL TRIAL COMBINING SURGICAL RESECTION WITH DIRECT INTRACEREBRAL INJECTION OF IMMUNE CHECKPOINT INHIBITORS IN PATIENTS WITH RECURRENT GLIOBLASTOMA

INTRODUCTION

Intravenous (iv) administration of PD-1 blocking mAb is largely ineffective for the treatment of recurrent glioblastoma (rGB). Combination of iv-ipilimumab (IPI) plus nivolumab (NIVO) is associated with a high incidence of irAE. Intracerebral (ic) administration of immune-checkpoint inhibiting mAb following the resection of rGB could be a more effective and safer alternative to iv-dosing.

METHODS

Patients underwent maximal safe resection of their rGB followed by ic-injection of 10mg IPI (cohort-1) or 5mg IPI plus 10mg NIVO (cohort-2) in the wall of the resection cavity. In both cohorts 10mg nivolumab was administered iv for a max of 6 doses, starting 1 day pre-operatively.

RESULTS

21 pts were included (3 in C-1, 18 in C-2; 8F/13M; median age 56y [range 38–72]; 17 de novo GB, 4 secGB). All patients underwent maximal safe surgical resection followed by ic-injection of IPI and NIVO as planned. Median number of iv-administrations of NIVO was 5 (range 1–8). Treatment was generally well tolerated. Postoperatively, 2 patients experienced a G3 symptomatic increase in perilesional cerebral edema with neurological deterioration, reversible upon steroid treatment. One patient had worsening neurological symptoms related to an inflammatory intracerebral cyst at the resection site, requiring surgical decompression 4 months post-study treatment. Most frequent AEs were fatigue (2pts G3, 8pts G2), postoperative fever (11pts G1) and headache (3pts G2); 1pt developed G3 pneumonitis. No other immune-related AEs or treatment-related deaths occurred. After median follow-up of 60 weeks, median PFS is 14.4 weeks (95% CI 11.2–17.6); 11/21 patients are alive, and 1- and 2y-OS% are respectively 46% (95% CI 19- 73%), and15% (95% CI 0–42%).

CONCLUSION

This is the first study demonstrating the safety and activity of combined surgical resection of rGB with local intracerebral administration of immune checkpoint-inhibiting mAb. Survival compares favorably to historical controls justifying further investigation of this experimental therapy.

ATIM-38. GLITIPNI: A PHASE 1B CLINICAL TRIAL COMBINING SURGICAL RESECTION WITH DIRECT INTRACEREBRAL INJECTION OF IMMUNE CHECKPOINT INHIBITORS IN PATIENTS WITH RECURRENT GLIOBLASTOMA

INTRODUCTION

Intravenous (iv) administration of PD-1 blocking mAb is largely ineffective for the treatment of recurrent glioblastoma (rGB). Combination of iv-ipilimumab (IPI) plus nivolumab (NIVO) is associated with a high incidence of irAE. Intracerebral (ic) administration of immune-checkpoint inhibiting mAb following the resection of rGB could be a more effective and safer alternative to iv-dosing.

METHODS

Patients underwent maximal safe resection of their rGB followed by ic-injection of 10mg IPI (cohort-1) or 5mg IPI plus 10mg NIVO (cohort-2) in the wall of the resection cavity. In both cohorts 10mg nivolumab was administered iv for a max of 6 doses, starting 1 day pre-operatively.

RESULTS

21 pts were included (3 in C-1, 18 in C-2; 8F/13M; median age 56y [range 38–72]; 17 de novo GB, 4 secGB). All patients underwent maximal safe surgical resection followed by ic-injection of IPI and NIVO as planned. Median number of iv-administrations of NIVO was 5 (range 1–8). Treatment was generally well tolerated. Postoperatively, 2 patients experienced a G3 symptomatic increase in perilesional cerebral edema with neurological deterioration, reversible upon steroid treatment. One patient had worsening neurological symptoms related to an inflammatory intracerebral cyst at the resection site, requiring surgical decompression 4 months post-study treatment. Most frequent AEs were fatigue (2pts G3, 8pts G2), postoperative fever (11pts G1) and headache (3pts G2); 1pt developed G3 pneumonitis. No other immune-related AEs or treatment-related deaths occurred. After median follow-up of 60 weeks, median PFS is 14.4 weeks (95% CI 11.2–17.6); 11/21 patients are alive, and 1- and 2y-OS% are respectively 46% (95% CI 19- 73%), and15% (95% CI 0–42%).

CONCLUSION

This is the first study demonstrating the safety and activity of combined surgical resection of rGB with local intracerebral administration of immune checkpoint-inhibiting mAb. Survival compares favorably to historical controls justifying further investigation of this experimental therapy.

A focused 35-minute whole body MRI screening protocol for patients with von Hippel-Lindau disease

BACKGROUND

Von Hippel-Lindau (VHL) disease is an autosomal dominantly inherited tumor syndrome. Affected patients develop central nervous system hemangioblastomas and abdominal tumors, among other lesions. Patients undergo an annual clinical screening program including separate magnetic resonance imaging (MRI) of the brain, whole spine and abdomen. Consequently, patients are repeatedly subjected to time-consuming and expensive MRI scans, performed with cumulative Gadolinium injections. We report our experience with a 35-min whole body MRI screening protocol, specifically designed for detection of VHL-associated lesions.

METHODS

We designed an MRI protocol dedicated to the typical characteristics of VHL-associated lesions in different imaging sequences, within the time frame of 35 min. Blank imaging of the abdomen is carried out first, followed by abdominal sequences with Gadolinium contrast. Next, the full spine is examined, followed by imaging of the brain. A single dose of contrast used for abdominal imaging is sufficient for further highlighting of spine- and brain lesions, thus limiting the Gadolinium dosage. We used 1.5 Tesla equipment, dealing with fewer artifacts compared to a 3 Tesla system for spine- and abdominal imaging, while preserving acceptable quality for central nervous system images. In addition, imaging on a 1.5 Tesla scanner is slightly faster.

RESULTS

From January 2016 to November 2018, we performed 38 whole body screening MRIs in 18 VHL patients; looking for the most common types of VHL lesions in the abdomen, spine, and brain, both for new lesions and follow-up. The one-step approach MRI examinations lead to 6 surgical interventions for clinically significant or symptomatic hemangioblastomas in the brain and spine. One renal cell carcinoma was treated with radiofrequency ablation. In comparison with previous conventional MRI scans of the same patients, all lesions were visible with the focused protocol.

CONCLUSIONS

Annual screening in VHL disease can be done in a rapid, safe and sensitive way by using a dedicated whole body MRI protocol; saving MRI examination time and limiting Gadolinium dose.

Polyglobulia in patients with hemangioblastomas is related to tumor size but not to serum erythropoietin

Background

Hemangioblastomas are associated with elevated hemoglobin (Hb) levels (polyglobulia), which is associated with a higher risk for cerebral stroke, cardiac infarction and pulmonary embolism. The pathomechanism of polyglobulia remains unclear and different theories have been postulated. Among those are elevated serum erythropoietin (EPO) levels caused by secretion of the tumor or associated tumor cyst.

Methods

To elucidate the pathomechanism, we systematically investigated the relation between polyglobulia, serum EPO level, size of the solid tumor and associated cyst in hemangioblastomas. We prospectively evaluated hemoglobin and EPO levels in a series of 33 consecutive patients operated on hemangioblastomas in our center. We measured the size of the solid tumor and associated cyst in magnetic resonance imaging. Statistical evaluations were performed using the Fisher's exact test and student's t-test.

Results

As a result five patients had elevated hemoglobin levels. Only one of these had an elevated serum EPO level. Of 26 patients with normal hemoglobin levels, 4 patients had elevated EPO levels.Patients with low or normal hemoglobin levels (84%) had an average tumor size of 0.8 cm³, which differed significantly from patients with elevated hemoglobin levels (16%), who had an average solid tumor size of 8.0 cm³ (p < 0.05). We did not observe a significant correlation between EPO levels or polyglobulia and associated cysts.

Conclusions

We therefore conclude that in contrast to previous case reports and interpretations, our data show no correlation between polyglobulia and EPO levels or associated cysts in patients with hemangioblastomas. In fact, it is the size of the solid tumor that correlates with polyglobulia.The study was retrospectively registered in the German Clinical Trial Registry on 10 July 2014; Trial registration: DRKS00006310.

Posterior approach for anteriorly located cervical spinal cord hemangioblastomas: technical note

The surgical management of anteriorly located spinal cord hemangioblastomas remains a challenge. Different approaches have been published, of which the anterior approach seems to be the most obvious and commonly used. A posterior approach might be more suitable in certain patients, especially in cases of cystic hemangioblastomas. The authors present 3 cases of anterior spinal hemangioblastomas, which were all resected via a posterior approach. The authors discuss the rationale for choosing this approach and explain the technique in detail.

Central nervous system gadolinium accumulation in patients undergoing periodical contrast MRI screening for hereditary tumor syndromes

Background

Patients with hereditary tumor syndromes undergo periodical magnetic resonance imaging (MRI) screening with Gadolinium contrast. Gadolinium accumulation has recently been described in the central nervous system after repeated administrations. The prevalence and rate of accumulation in different subgroups of patients are unknown. Neither are the mechanism nor clinical impact. This may cause uncertainty about the screening. To explore the prevalence and rate of Gadolinium accumulation in different subgroups, we retrospectively analyzed MRIs of patients with von Hippel-Lindau disease (VHL) and Tuberous Sclerosis Complex (TSC).

Methods

We determined the prevalence and rate of accumulation in the dentate nucleus and globus pallidus on unenhanced T1-weighted MRI from VHL and TSC patients. We compared the signal intensities of these regions to the signal intensity of the pons. We evaluated the impact of number of MRIs, kidney function and liver function on Gadolinium accumulation.

Results

Twenty eight VHL patients and 24 TSC patients were included. The prevalence of accumulation in the dentate nucleus and globus pallidus increased linearly according to number of Gadolinium enhanced MRIs and was higher in the VHL group (100%). A significant linear correlation between number of MRIs and increased signal intensity was observed in the VHL group.

Conclusions

Gadolinium accumulation occurs in almost all patients undergoing contrast MRI screening after >5 MRIs. We advocate a screening protocol for patients with hereditary tumor syndromes that minimizes the Gadolinium dose. This can be accomplished by using a single administration to simultaneously screen for brain, spine and/or abdominal lesions, using an MRI protocol focused on either VHL- or TSC-specific lesions. Higher prevalence and rate of accumulation in VHL patients may be explained by the typical vascular leakage accompanying central nervous system hemangioblastomas.

Intracerebral Hematoma Due to Aneurysm Rupture: Are There Risk Factors Beyond Aneurysm Location?

BACKGROUND

Along with subarachnoid hemorrhage (SAH), a ruptured aneurysm may also cause an intracerebral hematoma (ICH), which negatively impacts the functional outcome of SAH.

OBJECTIVE

To identify independent risk factors of aneurysmal ICH.

METHODS

Six hundred thirty-two consecutive patients with aneurysmal SAH treated at our institution from January 2005 to December 2012 were eligible for this study. Demographic parameters and preexisting comorbidities of patients, as well as various clinical and radiographic characteristics of SAH were correlated with the incidence and volume of aneurysmal ICH.

RESULTS

One hundred fifty-five patients (25%) had ICH on initial computed tomography with a mean volume of 26.7 mL (±26.8 mL). Occurrence and volume of ICH were associated with the location (distal anterior or middle cerebral artery >proximal anterior cerebral or internal carotid artery >posterior circulation, P < .001/P < .001) and size (>12 mm, P = .026/P < .001) of the ruptured aneurysm. Vascular risk factors independently increased the risk of ICH as well (arterial hypertension: odds ratio [OR] = 1.62, P = .032; diabetes mellitus: OR = 3.06, P = .009), while the use of aspirin (P = .037) correlated with the volume of ICH. The predictors of ICH were included into a risk score (0-9 points) that strongly predicted the occurrence of ICH (P = .01). Poor functional outcome after SAH was independently associated with the occurrence of ICH (P = .003, OR = 2.77) and its volume (P = .001, OR = 1.07 per-mL-increase).

CONCLUSION

Aneurysmal ICH is strongly associated with poorer functional outcome and seems to be predictable even before the bleeding event. The proposed risk factors for aneurysmal ICH require further validation and may be considered for treatment decisions regarding unruptured intracranial aneurysms.

ABBREVIATIONS

ACA, anterior cerebral arteryDHC, decompressive hemicraniectomyEVD, external ventricular drainageICA, internal carotid arteryICH, intracerebral hematomaMCA, middle cerebral arterymRS, modified Rankin scalePC, posterior circulationSAH, subarachnoid hemorrhageSIRS, systemic inflammatory response syndromeTCD, transcranial Doppler sonography.

Early Vasospasm after Aneurysmal Subarachnoid Hemorrhage Predicts the Occurrence and Severity of Symptomatic Vasospasm and Delayed Cerebral Ischemia

Background: Cerebral vasospasm usually develops several days after subarachnoid hemorrhage (SAH) and is generally acknowledged as a strong outcome predictor. In contrast, much less is known about the nature and eventual consequences of early angiographic vasospasm (EAVS) seen on admission digital subtraction angiography (DSA). Therefore, we aimed at identifying the risk factors and clinical impact of EAVS after SAH. Methods: Five hundred and thirty-one SAH patients with admission DSA performed within 72 h after the bleeding event were selected from a comprehensive database containing all consecutive SAH patients treated at our institution between January 2005 and December 2012. Predictors of EAVS, as well as associations between EAVS and delayed vasospasm-related complications, and unfavorable outcome (defined as modified Rankin scale >3) were evaluated in univariate and multivariate analyses. Results: EAVS was seen on 60 DSAs (11.3%) and was independently correlated with delayed symptomatic vasospasm requiring intra-arterial spasmolysis (OR 5.24, p < 0.0001), angioplasty (OR 2.56, p = 0.015) and repetitive endovascular treatment (OR 4.71, p < 0.0001). EAVS also increased the risk for multiple versus single territorial infarction on the follow-up CT scan(s) (OR 2.04, p = 0.047) and independently predicted unfavorable outcome (OR 2.93, p = 0.008). The presence of radiographic signs suspicious for fibromuscular dysplasia were independently associated with the occurrence of EAVS (OR 2.98, p = 0.026) and the need for repetitive endovascular vasospasm treatment (OR 3.95, p = 0.019). Conclusions: In view of the strong correlation with delayed symptomatic vasospasm and its ischemic complications, EAVS can be considered an alerting signal for severe symptomatic vasospasm. Therefore, more attention should be paid to the presence of EAVS on admission DSA.

The predictors and clinical impact of intraventricular hemorrhage in patients with aneurysmal subarachnoid hemorrhage

Background

Intraventricular hemorrhage is known to complicate the course and outcome of aneurysmal subarachnoid hemorrhage.

Aims

To identify independent risk factors for intraventricular hemorrhage development and its severity during aneurysm rupture.

Methods

Six hundred and twenty-five subarachnoid hemorrhage patients treated at our institution between January 2005 and December 2012 were included. The severity of intraventricular hemorrhage was assessed according to the original Graeb score. Clinical and radiographic features of patients present at the bleeding event were tested as potential risk factors for intraventricular hemorrhage. The characteristics of intraventricular hemorrhage were correlated with the clinical course and outcome.

Results

Intraventricular hemorrhage was present in 206 patients (33%) and was independently predicted by patient’s age (p = 0.001, odds ratio (OR) = 1.02/year of age increase), aneurysm size (p = 0.031, OR = 1.05/mm increase), and location (p < 0.0001, OR = 3.2 for aneurysms of posterior circulation). The severity of intraventricular hemorrhage was predicted by aneurysm size (p = 0.023) and location (higher severity for aneurysms of anterior circulation, p = 0.01). The presence of intraventricular hemorrhage (p < 0.0001, OR = 4.1) and intraventricular hemorrhage severity of >3 points on the Graeb score (p = 0.029, OR = 3.4) was independently associated with poor outcome. Shunt dependency was associated only with the occurrence of intraventricular hemorrhage (p < 0.0001, OR = 2.8) while the severity of intraventricular hemorrhage influenced the timing of shunt placement (p = 0.0156).

Conclusions

Increasing age, aneurysm size, and location in the posterior circulation are the main risk factors for occurrence of aneurysmal intraventricular hemorrhage, which is independently associated with poor outcome. The severity of intraventricular hemorrhage, however, is higher if the aneurysm is located in the anterior circulation and has impact on functional outcome, but not on shunt dependency.

Unilateral contrast-enhancing pontomedullary lesion due to an intracranial dural arteriovenous fistula with perimedullary spinal venous drainage: the exception that proves the rule

A large spectrum of possible diagnoses must be taken into consideration when a contrast-enhancing lesion of the pontomedullary region is found on MRI. Among these diagnoses are neoplastic, inflammatory, and infectious, as well as vascular pathologies. The authors report a rare case of an intracranial dural arteriovenous fistula (DAVF) with perimedullary spinal venous drainage (Cognard Type V) that initially presented as a unilateral contrast-enhancing pontomedullary lesion mimicking a brainstem neoplasm in a 76-year-old man. Following occlusion of the DAVF by transarterial embolization that resulted in clinical and radiological improvement, the fistula recurred 10 months later and was finally cured by a combined endovascularand surgical approach that resulted in complete occlusion. Clinical symptoms and MRI findings gradually improved following this treatment. A literature review on the MRI findings of Cognard Type V DAVF was performed. Centrally located medullary or pontomedullary edema represents the typical imaging finding, while unilateral edema as seen in the authors’ patient is exceptionally rare. The hallmark imaging finding suggestive of DAVF consisting of perimedullary engorged vessels may not always be present or may only be very subtly visible. Therefore, the authors suggest performing contrast-enhanced MR angiography or even digital subtraction angiography in the presence of an unclear edematous brainstem lesion before scheduling stereotactic biopsy.

Outcome Prediction after Non-aneurysmal Non-traumatic Subarachnoid Hemorrhage

Contrary to aneurysmal bleeding, non-aneurysmal non-traumatic subarachnoid hemorrhage (NASAH) is rarely associated with unfavorable clinical outcome, cerebral infarction and vasospasm. We aimed to identify independent predictors for a poor clinical course and outcome after NASAH. All patients with NASAH treated at our institution between January 2005 and December 2012 were retrospectively analyzed. Collected demographic, clinical and radiographic variables were divided into primary (admission) and secondary (follow-up) parameters. Independent predictors of unfavorable outcome (defined as modified Rankin scale=3-6), cerebral infarction and development of vasospasm were identified. In addition, a risk score for the estimation of clinical outcome was designed. Out of population with 157 NASAH patients, unfavorable outcome was documented in 57 cases (36.3%) at discharge and in 17 cases (10.8%) after 6 months. Cerebral infarction(s) were found in 7 patients (4.3%). In multivariate analyses, higher age (≥65 years), poorer initial clinical condition measured by Hunt & Hess grade and diffuse basal bleeding pattern were independent outcome predictors and therefore included in the risk score (1-8 points). The risk score correlated with outcome at discharge (p<0.0001) and clinical improvement after 6 months (p=0.0238). A diffuse basal bleeding pattern predicted the detection of vasospasm by transcranial Doppler (p=0.001). Poor initial clinical condition (p=0.028) and vasospasm (p=0.031) were associated with the occurrence of cerebral infarction. NASAH patients with higher age, bad clinical condition on admission and diffuse bleeding pattern are prone to unfavorable outcome. The proposed risk score helps to identify patients with poor prognosis after NASAH.

Hemangioblastomas and neurogenic polyglobulia

BACKGROUND

Neurogenic polyglobulia occurs with central nervous system hemangioblastomas. Among the suggested mechanisms are extramedullary hematopoiesis in the tumor tissue and germline mutations of the von Hippel-Lindau (VHL) tumor suppressor gene.

OBJECTIVE

To determine the frequency and driving mechanisms of polyglobulia in central nervous system hemangioblastomas.

METHODS

We performed a retrospective analysis of pre- and postoperative (at 3 and 12 months) hemoglobin levels in a consecutive series of patients with hemangioblastomas operated on in our institution from 1996 to 2009. We performed molecular genetic analyses for mutations of the VHL tumor suppressor gene.

RESULTS

Preoperative hemoglobin levels were available from 164 patients. The average hemoglobin level (15.2 g/dL in males and 13.1 g/dL in females) was within normal range according to our standards. Of 22 patients with increased preoperative hemoglobin levels (>17 g/dL in males and >15 g/dL in females), 8 presented with pathological hemoglobin (>18.5 g/dL in males and >16.5 g/dL in females) according to World Health Organization criteria. Surgical removal of the hemangioblastoma resulted in a permanent cure of polyglobulia in all patients. Six of the 8 patients with pathological hemoglobin elevation carried a germline mutation of the VHL tumor suppressor gene.

CONCLUSION

Neurogenic polyglobulia occurs in a subset of patients with hemangioblastomas. This phenomenon is mostly observed in VHL mutation carriers, but also occurs in patients with sporadic hemangioblastomas. Removal of the tumor results in the permanent cure of polyglobulia. Our observations suggest that polyglobulia is an effect by the tumor itself, either due to paraneoplasia or extramedullary hematopoiesis.

Sequence variations in the von Hippel-Lindau tumor suppressor gene in patients with intracranial aneurysms

BACKGROUND

The rupture of intracranial aneurysms leads to subarachnoid hemorrhage, which is often associated with poor outcome. Preventive treatment of unruptured intracranial aneurysms is possible and recommended. However, the lack of candidate genes precludes identifying patients at risk by genetic analyses. We observed intracranial aneurysms in 2 patients with von Hippel-Lindau (VHL) disease and the known disease-causing mutation c.292T > C (p.Tyr98His) in the VHL tumor suppressor gene. This study investigates whether the VHL gene is a possible candidate gene for aneurysm formation.

METHODS

Patients with intracranial aneurysms admitted to our department between 2006 and 2009 were enrolled. The peripheral leukocyte DNA of 200 patients was investigated for sequence variations in the VHL gene using denaturing high performance liquid chromatography. Peripheral leukocyte DNA of 100 randomly sampled probands was investigated as a control group. The allelic frequencies of sequence variations between both groups were compared using the Fisher exact test.

RESULTS

Fourteen of 200 patients with intracranial aneurysms had sequence variations at 6 different loci in the VHL gene. In contrast, no sequence variations were identified in 100 probands in the control group (P = 0.0062). However, none of the single-sequence variations had a statistically significant difference in the allelic frequencies compared to the control group.

CONCLUSIONS

There is accumulating evidence for a genetic basis of aneurysm development. Our investigations lead to the conclusion that the VHL gene is potentially involved in the formation of intracranial aneurysms in a subset of patients. Additional candidate genes need to be identified in order to develop sensitive genetic screening for at-risk patients.

Monitoring motor function during resection of tumours in the lower brain stem and fourth ventricle

OBJECTIVES

Even in the days of modern microsurgery, the removal of a brain stem lesion remains a surgical challenge. Especially when operating on children, the prognosis is directly related to the radicality of the resection; however, a radical resection is often associated with surgical morbidity. Intraoperative neuromonitoring could help to minimise the surgical morbidity, but few studies have been performed to clarify the value of this monitoring. We investigated a prospective series of 21 patients with lesions involving the brain stem for the prognostic value and benefits of neuromonitoring.

METHODS

We performed intraoperative neuromonitoring of cranial nerve function by electromyography (EMG) and motor evoked potential (MEP). The results were correlated with postoperative neurological deficits.

CONCLUSIONS

There is a good correlation between intraoperative neurophysiological events and postoperative neurological deficits in patients with lesions of the brain stem. In general, transient, prolonged, spontaneous activity in EMG is associated with a transient paresis of the respective muscle, whereas a permanent spontaneous activity is associated with a permanent deficit. Intraoperative neuromonitoring reliably predicts postoperative neurological function in patients with tumours of the lower brain stem and fourth ventricle. This neuromonitoring guides the neurosurgeon in the operation and may decrease surgical morbidity. We recommend using monitoring of MEP and EMG of the lower cranial nerves in surgery on all patients with lesions involving the lower brain stem and fourth ventricle.

Surgical treatment of hemangioblastomas of the central nervous system in pediatric patients

OBJECTIVE

Hemangioblastomas are histologically benign lesions that occur sporadically or as a manifestation of von Hippel-Lindau disease (VHL). The treatment strategy of these neoplasms is complicated by their unpredictable growth patterns and the often irreversible neurological deficits they may cause. This study aims to outline the neurosurgical treatment options and to address the ongoing debate of surgical timing in pediatric patients with VHL.

PATIENTS AND METHODS

Thirteen consecutive pediatric patients (mean age 15.1 years) who were surgically treated for intracranial (n=8) or spinal hemangioblastomas (n=5) were included in this study (range of clinical follow up 12-86 months). Ten patients were affected by von Hippel-Lindau and three were with sporadic tumors. Serial examinations, preoperative MRI studies, and operative findings were reviewed.

RESULTS

Patients with cerebellar and intramedullary hemangioblastomas did not develop additional neurological deficits postoperatively. Two patients with brainstem tumors exhibited transient hemiparesis and caudal nerve palsy, respectively. Both patients recovered completely from their postoperative deficits. Preoperatively symptomatic patients with spinal tumors did not deteriorate nor improve after surgery. During the observed follow-up periods, no tumor recurrences were observed.

CONCLUSION

Central nervous system (CNS) hemangioblastomas in pediatric patients can be surgically treated with low morbidity. Based on our experience, we recommend considering also the surgical removal of asymptomatic hemangioblastomas with proven radiological progression to prevent the development of permanent neurological deficits. Molecular screening of every pediatric patient and family is mandatory to enable the detection of extraneurological tumors and the development of an efficient therapeutic strategy.

Risk of hemorrhage in hemangioblastomas of the central nervous system

OBJECTIVE

Hemangioblastomas are benign vascular tumors of the central nervous system. Several cases of spontaneous hemorrhage within these tumors have been reported. However, the risk of hemorrhage in these tumors remains unknown.

METHODS

To clarify the incidence of hemorrhage in hemangioblastomas, we reviewed our large clinical database of 277 patients with central nervous system hemangioblastomas for the incidence of spontaneous or perioperative hemorrhage. Clinical characteristics such as tumor size, tumor location, von Hippel-Lindau disease status, and clinical symptoms before hemorrhage were correlated with hemorrhage risk. Furthermore, we reviewed the literature for cases of spontaneous hemorrhage from hemangioblastoma.

RESULTS

Among all patients in our series, we observed seven cases of spontaneous hemorrhage from a hemangioblastoma within the summarized follow-up time. Thus, we calculate a spontaneous hemorrhage probability of 0.0024 per person per year. The average diameter of tumors that bled was 3 cm in our series and 2.3 cm in the literature review, whereas the average diameter of hemangioblastomas in major series ranges from 0.8 to 1.1 cm. Furthermore, we have observed severe postoperative hemorrhage in two extraordinarily large solid hemangioblastomas (4 and 5 cm).

CONCLUSION

The overall incidence of hemorrhage in patients with hemangioblastoma is low. An important indicator for the probability of hemorrhage is tumor size, as spontaneous or postoperative hemorrhage occurred exclusively in extraordinarily large tumors. Hemangioblastomas smaller than 1.5 cm (the vast majority of these tumors) harbor virtually no risk of spontaneous hemorrhage.

Far lateral supracerebellar infratentorial approach for the treatment of upper brainstem gliomas: clinical experience with pediatric patients

OBJECTIVE

Surgical exposure of intrinsic lesions located lateral to the brainstem still represents a challenging task. The aim of this study was to assess the feasibility of the extracerebral far lateral supracerebellar infratentorial (FLSI) approach for the treatment of gliomas located in the upper brainstem in the pediatric population.

METHODS AND RESULTS

Between 1992 and 2002, seven patients (mean age 8.7 years) with tumors of glial origin (WHO I-IV) located mainly in the pontomesencephalic region were operated with the FLSI approach in a sitting position. Satisfactory extent of resection without additional morbidity was achieved.

CONCLUSION

In a carefully selected pediatric patient population, the FLSI approach proved to be a feasible and effective surgical route for the treatment of upper brainstem gliomas.

Characterization of Hemangioblastomas of Spinal Nerves

OBJECTIVE:

Hemangioblastoma is classified as a benign tumor of the central nervous system. Peripheral nervous system hemangioblastomas to date have been described only in a few case reports. Experience in treating patients with these rare lesions, which harbor diagnostic and therapeutic pitfalls, is limited.

METHODS:

To characterize these lesions better, we reviewed our hemangioblastoma database for patients who underwent surgery for extradural hemangioblastoma of the spinal nerve.

RESULTS:

Between 1983 and 2003, six patients underwent surgery for spinal nerve hemangioblastomas at our institution. These tumors occurred in 2% of all patients with hemangioblastomas of the central nervous system, or 6% of all patients with spinal hemangioblastomas. The occurrence did not differ in von Hippel-Lindau disease cases versus sporadic cases. Radiographically, the tumors easily could be mistaken for schwannomas or metastases; however, they did have some typical features. If a hemangioblastoma was not suspected primarily, profuse bleeding could complicate surgery. Most of the tumors arose from the dorsal sensory fascicles. The vascular supply was from extradural circulation. In general, the surgical outcome of these lesions was good, and permanent neurological deficit was rare. However, local recurrence was observed in three of six patients.

CONCLUSION:

These tumors harbor diagnostic and therapeutic pitfalls. In general, the tumors are surgically more challenging, and clinically significant bleeding as well as local tumor recurrence is more common than in intradural hemangioblastomas, mostly because of the frequency of incorrect initial radiographic diagnosis. We suggest that because of the surgical consequences, hemangioblastoma should always be considered to be an important radiological differential diagnosis for nerve sheath tumors. Angiography can bring clarification to ambiguous cases.

Treatment of Intramedullary Hemangioblastomas, with Special Attention to von Hippel-Lindau Disease

OBJECTIVE

Hemangioblastomas of the central nervous system are rare vascular tumors that can occur as sporadic lesions or as component tumors of autosomal dominant von Hippel-Lindau disease. With the availability of magnetic resonance imaging, asymptomatic tumors are detected more frequently, especially among patients with von Hippel-Lindau disease, and the questions of whether and when these lesions should be treated arise. To identify surgical outcomes and the timing of surgery for intramedullary hemangioblastomas, we retrospectively analyzed data for a series of 28 consecutive patients whom we surgically treated for intramedullary hemangioblastomas in the past 10 years.

METHODS

All tumors were completely removed. Functional grades, according to the McCormick scale, were determined before and after surgery and in follow-up assessments. Several clinical characteristics were correlated with changes in functional grades in follow-up assessments, compared with preoperative grades.

RESULTS

Functional grades in follow-up assessments improved for 28.6% of the patients and remained unchanged for 71.4%. No patient was in worse condition, compared with preoperative status. Peritumoral edema on preoperative magnetic resonance imaging scans was correlated with significantly higher surgical morbidity rates. Four asymptomatic patients were surgically treated because of tumor or pseudocyst progression on serial magnetic resonance imaging scans. All of those patients remained asymptomatic postoperatively.

CONCLUSION

Intramedullary hemangioblastomas can be removed with low surgical morbidity rates and excellent long-term prognoses. The timing of surgery for patients with von Hippel-Lindau disease and multiple lesions remains a matter of debate. On the basis of our data, we established the strategy of operating also on asymptomatic lesions that exhibit radiological progression, before significant neurological deficits occur, which are often not reversible.

Latent abscess formation adjacent to a non-functioning intraventricular catheter

CASE REPORT

A 16-year-old male patient who had been treated at the age of 13 months with a ventriculoperitoneal (VP) shunt due to obstructive hydrocephalus was presented to our department for a routine follow-up examination. The patient had tolerated well a shunt disconnection in 1990 and the distal part had been removed. Six years later radiological evaluation revealed an intracerebral mass adjacent to the remaining intraventricular catheter. The mass, histologically classified as an abscess, had to be removed 3 years later due to disease progression, although the patient remained asymptomatic.

DISCUSSION

This case is of particular interest because it demonstrates the extremely delayed onset and progressive course of a well-known complication of VP shunt systems in an asymptomatic patient. In addition, the reported case raises the question of whether a non-functioning shunt needs to be removed or not.