Falcotentorial Meningiomas: Insights from Surgical Strategies and Clinical Outcomes.

Background: Falcotentorial meningiomas are exceptionally uncommon tumors, presenting a challenge for neurosurgeons due to their close proximity to vital structures. Gross total resection represents the standard of treatment for these tumors. However, care must be taken when surgically approaching these lesions, since damaging neurovascular structures may cause unacceptable morbidity. Selecting the optimal surgical approach for each tumor is of paramount importance when treating these patients. Methods: The authors reviewed medical records to identify all patients with falcotentorial meningiomas who underwent resection at the University Hospital of Freiburg between January 2001 and December 2021. Clinical and imaging data, surgical management, and clinical outcomes were analyzed. Results: Falcotentorial meningiomas occurred in 0.7% (15 of 2124 patients) of patients with intracranial meningiomas. Of these 15 patients, 8 were female and 7 male. The occipital interhemispheric approach was used in nine patients, the supracerebellar infratentorial approach in five patients, and the retrosigmoidal approach in one patient. Three patients developed visual field deficits after surgical resection. Incomplete resection was significantly associated with tumor progression (p < 0.05). Conclusions: Individualized surgical strategies, guided by preoperative imaging and classification systems, play a crucial role in optimizing patient care. Among the available approaches, the occipital interhemispheric and supracerebellar infratentorial approaches are frequently employed and considered among the safest options for these tumors.

Surgical Outcome of Patients With Supratentorial Meningiomas Aged 80 Years or Older-Retrospective International Multicenter Study.

BACKGROUND AND OBJECTIVES: Demographic changes will lead to an increase in old patients, a population with significant risk of postoperative morbidity and mortality, requiring neurosurgery for meningiomas. This multicenter study aims to report neurofunctional status after resection of patients with supratentorial meningioma aged 80 years or older, to identify factors associated with outcome, and to validate a previously proposed decision support tool. METHODS: Neurofunctional status was assessed by the Karnofsky Performance Scale (KPS). Patients were categorized in poor (KPS ≤40), intermediate (KPS 50-70), and good (KPS ≥80) preoperative subgroups. Volumetric analyses of tumor and peritumoral brain edema (PTBE) were performed; volumes were scored as small (<10 cm 3 ), medium (10-50 cm 3 ), and large (>50 cm 3 ). RESULTS: The study population consisted of 262 patients, and the median age at surgery was 83.0 years. The median preoperative KPS was 70; 117 (44.7%) patients were allotted to the good, 113 (43.1%) to the intermediate, and 32 (12.2%) to the poor subgroup. The median tumor and PTBE volumes were 30.2 cm 3 and 27.3 cm 3 ; large PTBE volume correlated with poor preoperative KPS status ( P = .008). The 90-day and 1-year mortality rates were 9.0% and 13.2%, respectively. Within the first postoperative year, 101 (38.5%) patients improved, 87 (33.2%) were unchanged, and 74 (28.2%) were functionally worse (including deaths). Each year increase of age associated with 44% (23%-70%) increased risk of 90-day and 1-year mortality. In total, 111 (42.4%) patients suffered from surgery-associated complications. Maximum tumor diameter ≥5 cm (odds ratio 1.87 [1.12-3.13]) and large tumor volume (odds ratio 2.35 [1.01-5.50]) associated with increased risk of complications. Among patients with poor preoperative status and large PTBE, most (58.3%) benefited from surgery. CONCLUSION: Patients with poor preoperative neurofunctional status and large PTBE most often showed postoperative improvements. The decision support tool may be of help in identifying cases that most likely benefit from surgery.

Digital Patient-Reported Outcome Measures Assessing Health-Related Quality of Life in Skull Base Diseases-Analysis of Feasibility and Pitfalls Two Years after Implementation.

Health-related quality of life (HRQoL) assessment is becoming increasingly important in neurosurgery following the trend toward patient-centered care, especially in the context of skull base diseases. The current study evaluates the systematic assessment of HRQoL using digital patient-reported outcome measures (PROMs) in a tertiary care center specialized in skull base diseases. The methodology and feasibility to conduct digital PROMs using both generic and disease-specific questionnaires were investigated. Infrastructural and patient-specific factors affecting participation and response rates were analyzed. Since August 2020, 158 digital PROMs were implemented in skull base patients presenting for specialized outpatient consultations. Reduced personnel capacity led to significantly fewer PROMs being conducted during the second versus (vs.) the first year after introduction (mean: 0.77 vs. 2.47 per consultation day, p = 0.0002). The mean age of patients not completing vs. those completing long-term assessments was significantly higher (59.90 vs. 54.11 years, p = 0.0136). Follow-up response rates tended to be increased with recent surgery rather than with the wait-and-scan strategy. Our strategy of conducting digital PROMs appears suitable for assessing HRQoL in skull base diseases. The availability of medical personnel for implementation and supervision was essential. Response rates during follow-up tended to be higher both with younger age and after recent surgery.

Accuracy of augmented reality-guided drainage versus stereotactic and conventional puncture in an intracerebral hemorrhage phantom model.

BACKGROUND: Minimally invasive intracranial drain placement is a common neurosurgical emergency procedure in patients with intracerebral hemorrhage (ICH). We aimed to retrospectively investigate the accuracy of conventional freehand (bedside) hemorrhage drain placement and to prospectively compare the accuracy of augmented/mixed reality-guided (AR) versus frame-based stereotaxy-guided (STX) and freehand drain placement in a phantom model. METHODS: A retrospective, single-center analysis evaluated the accuracy of drain placement in 73 consecutive ICH with a visual rating of postinterventional CT data. In a head phantom with a simulated deep ICH, five neurosurgeons performed four punctures for each technique: STX, AR, and the freehand technique. The Euclidean distance to the target point and the lateral deviation of the achieved trajectory from the planned trajectory at target point level were compared between the three methods. RESULTS: Analysis of the clinical cases revealed an optimal drainage position in only 46/73 (63%). Correction of the drain was necessary in 23/73 cases (32%). In the phantom study, accuracy of AR was significantly higher than the freehand method (P<0.001 for both Euclidean and lateral distances). The Euclidean distance using AR (median 3 mm) was close to that using STX (median 1.95 mm; P=0.023). CONCLUSIONS: We demonstrated that the accuracy of the freehand technique was low and that subsequent position correction was common. In a phantom model, AR drainage placement was significantly more precise than the freehand method. AR has great potential to increase precision of emergency intracranial punctures in a bedside setting.

Increased Orbital Muscle Fraction Diagnosed by Semi-Automatic Volumetry: A Risk Factor for Severe Visual Impairment with Excellent Response to Surgical Decompression in Graves' Orbitopathy.

Graves' orbitopathy (GO) leads to increased orbital tissue and causes symptoms such as exophthalmos, functional complaints, or dysthyroid optic neuropathy. Different GO types with fat and/or muscle enlargement were identified, and increased muscle appears to particularly influence visual status and treatment response. The current study examines visual parameters dependent on orbital muscle volume fraction in a surgically treated GO cohort. After volumetric analysis of the preoperative orbital content, 83 orbits in 47 patients were categorized into predefined groups (increased or not-increased muscle fraction). All cases underwent pterional orbital decompression, and pre- and postoperative visual status was retrospectively analyzed. Forty-one orbits revealed increased and 42 orbits revealed not-increased muscle volume (mean fraction 29.63% versus (vs.) 15.60%). The preoperative visual acuity (VA) was significantly lower in orbits with increased vs. not-increased muscle volume (mean VA 0.30 vs. 0.53, difference 2.5 lines). After surgery, mean VA improved significantly by 1.7 lines in orbits with increased muscle volume. Not preoperative, but postoperative exophthalmos was significantly lower in orbits with not-increased muscle volume. Increased orbital muscle is associated with significantly reduced VA, but can be remarkably improved by pterional orbital decompression. Therefore, surgical therapy should be considered particularly in decreased VA with orbital muscle enlargement.

Surgical Repair of Skull Base CSF Leaks after Cisternography Diagnosis: Analysis of Validity and Surgical Outcome and Impact on Future Treatment Strategies.

Skull base cerebrospinal fluid (CSF) leaks can lead to severe complications and require appropriate diagnosis and treatment. Cisternography is applied when exact localization via conventional imaging is not successful. The present study is aimed at identifying factors with potential impact on radiological results and surgical success. Cisternography followed by surgical repair due to skull base CSF leaks was performed in 63 cases between 2002 and 2020. The clinical and radiological findings were analyzed retrospectively. The etiology of CSF leaks was traumatic in 30.2%, spontaneous in 36.5%, and iatrogenic in 33.3%. The sensitivity of cisternography was 87.9%. Spontaneous CSF leaks tended to be diagnosed less frequently via cisternography and were significantly less frequently localized intraoperatively. The median postoperative follow-up period was 34 months. The primary surgical success rate was 79.4%, with a significantly higher success rate for lateral than for anterior skull base defects. Surgical failure tended to be lower in iatrogenic and higher in traumatic defects. Cisternography proved to be a highly sensitive method to localize skull base CSF leaks and can be recommended for advanced diagnostics. Iatrogenic leaks seemed to be more likely to have a favorable surgical outcome, whereas traumatic leaks tended to have a lower surgical success rate.

Management of Medial Sphenoid Wing Meningioma Involving the Cavernous Sinus: A Single-Center Series of 105 Cases.

OBJECTIVE: Medial sphenoid wing meningiomas are among the three most common intracranial meningiomas. These tumors pose a challenge to neurosurgeons in terms of surgical treatment, as they may involve critical neurovascular structures and invade the cavernous sinus. In case of the latter, a complete resection may not be achievable. The purpose of this study was to investigate prognostic features affecting recurrence and progression-free survival (PFS) of medial sphenoid wing meningiomas involving the cavernous sinus, focusing on the contribution of surgery and postoperative radiotherapy. METHODS: A retrospective analysis was conducted of the database of our institution, and 105 cases of medial sphenoid wing meningioma with invasion of the cavernous sinus, which were treated between 1998 and 2019, were included. Surgical treatment only was performed in 64 cases, and surgical treatment plus postoperative radiotherapy was performed in 41 cases. Kaplan-Meier analysis was conducted to estimate median survival and PFS rates, and Cox regression analysis was applied to determine significant factors that were associated with each therapeutic modality. RESULTS: The risk of recurrence was significantly reduced after near-total resection (NTR) (p-value = 0.0011) compared to subtotal resection. Progression-free survival was also significantly prolonged after postoperative radiotherapy (p-value = 0.0002). CONCLUSIONS: Maximal safe resection and postoperative stereotactic radiotherapy significantly reduced the recurrence rate of medial sphenoid wing meningiomas with infiltration of the cavernous sinus.

A Retrospective Evaluation of the Retrosigmoidal Approach for Petroclival Meningioma Surgery and Prognostic Factors Affecting Clinical Outcome.

Introduction: Petroclival meningioma (PCM) remains a major neurosurgical challenge. There are still controversial strategic treatment concepts about surgical approach, the extent of resection, and postoperative radiotherapy. We aimed to evaluate prognostic factors influencing the progression-free survival (PFS) rates of PCM, with a particular focus on the retrosigmoidal approach, the role of the extent of resection, and postoperative radiotherapy. Methods: Eighty-nine patients with complete follow-up data were included. All patients were operated on via a retrosigmoidal approach, of whom 19 underwent gross total resection (GTR) and 70 underwent subtotal resection (STR). In the subgroups of tumors with infiltration of the cavernous sinus, 41 patients received near total resection (NTR) and 24 STR. Thirty-one patients received postoperative radiotherapy of the residual tumor and 58 were treated with surgery alone. Kaplan-Meier analyses and Cox regression were used to identify significant factors associated with treatment. Results: GTR (p=0.0107) and postoperative radiotherapy (p=0.014) were associated with significantly improved PFS. Even the subgroup analysis of extended PCM with infiltration of the cavernous sinus (CS) showed an advantage for PFS after near total resection (NTR) (p=0.0017). The additional radiotherapy of the residual tumor in the CS in this subgroup also showed a beneficial effect on PFS (p=0.012). Conclusion: The extension of surgical resection remains the most important prognostic factor in relation to oncological outcomes. However, the GTR of extended PCM with infiltration of the CS is associated with significant neurological morbidity and requires additional adjuvant therapy concepts. Postoperative radiotherapy is an important element in the treatment of the residual tumor after surgery.

Augmented reality-assisted craniofacial reconstruction in skull base lesions - an innovative technique for single-step resection and cranioplasty in neurosurgery.

Defects of the cranial vault often require cosmetic reconstruction with patient-specific implants, particularly in cases of craniofacial involvement. However, fabrication takes time and is expensive; therefore, efforts must be made to develop more rapidly available and more cost-effective alternatives. The current study investigated the feasibility of an augmented reality (AR)-assisted single-step procedure for repairing bony defects involving the facial skeleton and the skull base. In an experimental setting, nine neurosurgeons fabricated AR-assisted and conventionally shaped ("freehand") implants from polymethylmethacrylate (PMMA) on a skull model with a craniofacial bony defect. Deviations of the surface profile in comparison with the original model were quantified by means of volumetry, and the cosmetic results were evaluated using a multicomponent scoring system, each by two blinded neurosurgeons. Handling the AR equipment proved to be quite comfortable. The median volume deviating from the surface profile of the original model was low in the AR-assisted implants (6.40 cm3) and significantly reduced in comparison with the conventionally shaped implants (13.48 cm3). The cosmetic appearance of the AR-assisted implants was rated as very good (median 25.00 out of 30 points) and significantly improved in comparison with the conventionally shaped implants (median 14.75 out of 30 points). Our experiments showed outstanding results regarding the possibilities of AR-assisted procedures for single-step reconstruction of craniofacial defects. Although patient-specific implants still represent the gold standard in esthetic aspects, AR-assisted procedures hold high potential for an immediately and widely available, cost-effective alternative providing excellent cosmetic outcomes.

Progression-Free Survival, Prognostic Factors, and Surgical Outcome of Spheno-Orbital Meningiomas.

OBJECTIVE: Spheno-orbital meningiomas (SOM) are rare intracranial tumors that arise at the sphenoid wing. These tumors can invade important neurovascular structures making radical resection difficult, while residual tumors often lead to recurrence. The purpose of this study was to evaluate prognostic factors influencing the recurrence and progression-free survival (PFS) rates of spheno-orbital meningiomas, with a particular focus on the role of surgery and postoperative radiotherapy. METHODS: Between 2000 and March 2020, 65 cases of spheno-orbital meningioma were included, of which 50 cases underwent surgical treatment alone, and 15 cases underwent resection and radiotherapy. A Kaplan-Meier analysis was performed to provide median point estimates and PFS rates; further, Cox regression analysis was used to identify significant factors associated with treatment. RESULTS: Gross total resection significantly reduced the risk of recurrence (p-value = 0.0062). There was no significant benefit for progression-free survival after postoperative radiotherapy (p-value = 0.42). Additionally, spheno-orbital meningiomas with an invasion of the cavernous sinus and intraconal invasion showed significantly worse PFS compared to other locations (p-value = 0.017). CONCLUSION: The maximal safe resection remains the most important prognostic factor associated with lower recurrence rates and longer PFS in patients with spheno-orbital meningioma. The invasion of the cavernous sinus and intraconal invasion was an independent factor associated with worse PFS. Patients with postoperative high-precision radiotherapy did not show significantly better PFS due to the small number of patients.

Stereotactic cysto-ventricular catheters in craniopharyngiomas: an effective minimally invasive method to improve visual impairment and achieve long-term cyst volume reduction.

Craniopharyngiomas are typically located in the sellar region and frequently contain space-occupying cysts. They usually cause visual impairment and endocrine disorders. Due to the high potential morbidity associated with radical resection, several less invasive surgical approaches have been developed. This study investigated stereotactic-guided implantation of cysto-ventricular catheters (CVC) as a new method to reduce and control cystic components. Twelve patients with cystic craniopharyngiomas were treated with CVC in our hospital between 04/2013 and 05/2017. The clinical and radiological data were retrospectively analysed to evaluate safety aspects as well as ophthalmological and endocrine symptoms. The long-term development of tumour and cyst volumes was assessed by volumetry. The median age of our patients was 69.0 years and the median follow-up period was 41.0 months. Volumetric analyses demonstrated a mean reduction of cyst volume of 64.2% after CVC implantation. At last follow-up assessment, there was a mean reduction of cyst volume of 92.0% and total tumour volume of 85.8% after completion of radiotherapy. Visual acuity improved in 90% of affected patients, and visual field defects improved in 70% of affected patients. No patient showed ophthalmological deterioration after surgery, and endocrine disorders remained stable. Stereotactic implantation of CVC proved to be a safe minimally invasive method for the long-term reduction of cystic components with improved ophthalmological symptoms. The consequential decrease of total tumour volumes optimised conditions for adjuvant radiotherapy. Given the low surgical morbidity and the effective drainage of tumour cysts, this technique should be considered for the treatment of selected cystic craniopharyngiomas.

Pterional Orbit Decompression in Grave Disease with Dysthyroid Optic Neuropathy.

OBJECTIVE: The choice of surgical technique in sight-threatening Grave orbitopathy remains controversial. Available data are mostly derived from mixed cohorts with multiple surgical indications and techniques. The authors assessed predictors for visual outcome after standardized pterional orbital decompression for dysthyroid optic neuropathy. METHODS: Retrospective analysis of 62 pterional orbital decompressions performed on 40 patients with dysthyroid optic neuropathy. RESULTS: Visual acuity improved by an average of 3.8 lines in eyes with preoperative visual impairment (95% confidence interval [CI]: 1.8-5.8 lines, P < 0.001) and remained stable in eyes without prior visual impairment (95% CI -1.3 to 1 line, P = 0.81). Proptosis was reduced by an average of 3.1 mm (95% CI 1.8-4.3 mm, P < 0.001). Higher degrees of proptosis were predictive of worse visual outcomes (P = 0.017). New-onset diplopia developed in 2 patients, while previous diplopia resolved after surgery in 6 patients. CONCLUSIONS: This cohort is the largest series of pterional orbit decompressions and the first to focus exclusively on dysthyroid neuropathy. Complication rates were low. Decompression surgery was highly effective at restoring and maintaining visual acuity in patients with dysthyroid optic neuropathy.

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.

Hemangioblastoma and von Hippel-Lindau disease: genetic background, spectrum of disease, and neurosurgical treatment.

INTRODUCTION: Hemangioblastomas are rare, histologically benign, highly vascularized tumors of the brain, the spinal cord, and the retina, occurring sporadically or associated with the autosomal dominant inherited von Hippel-Lindau (VHL) disease. Children or adults with VHL disease have one of > 300 known germline mutations of the VHL gene located on chromosome 3. They are prone to develop hemangioblastomas, extremely rarely starting at age 6, rarely at age 12-18, and, typically and almost all, as adults. There is a plethora of VHL-associated tumors and cysts, mainly in the kidney, pancreas, adrenals, reproductive organs, and central nervous system. Due to a lack of causal treatment, alleviation of symptoms and prevention of permanent neurological deficits as well as malignant transformation are the main task. Paucity of data and the nonlinear course of tumor progression make management of pediatric VHL patients with hemangioblastomas challenging. METHODS: The Freiburg surveillance protocol was developed by combining data from the literature and our experience of examinations of > 300 VHL patients per year at our university VHL center. RESULTS: Key recommendations are to start screening of patients at risk by funduscopy with dilated pupils for retinal tumors with admission to school and with MRI of the brain and spinal cord at age 14, then continue biannually until age 18, with emergency MRI in case of neurological symptoms. Indication for surgery remains personalized and should be approved by an experienced VHL board, but we regard neurological symptoms, rapid tumor growth, or critically large tumor/cyst sizes as the key indications to remove hemangioblastomas. Since repeated surgery on hemangioblastomas in VHL patients is not rare, modern neurosurgical techniques should encompass microsurgery, neuronavigation, intraoperative neuromonitoring, fluorescein dye-based intraoperative angiography, intraoperative ultrasound, and minimally invasive approaches, preceded in selected cases by endovascular embolization. Highly specialized neurosurgeons are able to achieve a very low risk of permanent morbidity for the removal of hemangioblastomas from the cerebellum and spinal cord. Small retinal tumors of the peripheral retina can be treated by laser coagulation, larger tumors by cryocoagulation or brachytherapy. CONCLUSION: We consider management at experienced VHL centers mandatory and careful surveillance and monitoring of asymptomatic lesions are required to prevent unnecessary operations and minimize morbidity.

Spinal paraganglioma as unusual finding in von Hippel-Lindau disease.

A 20-year-old patient with a history of von Hippel-Lindau disease reported on thoracic back pain radiating to the left shoulder for 10 weeks. Magnetic resonance imaging revealed a progressive contrast-enhancing tumor (14 × 21 × 28 mm) compressing the spinal cord and extending into the left neural foramen at T5/6. After embolization of supplying vessels, the tumor was completely resected via hemilaminectomy of T5. The postoperative course was uneventful without surgery related morbidity. The pathological examination disclosed a paraganglioma WHO grade I. We discuss the differential diagnoses and pitfalls of this unexpected finding in this patient with von Hippel-Lindau disease.

Impact of Stereotactic Ventriculocisternostomy on Delayed Cerebral Infarction and Outcome After Subarachnoid Hemorrhage.

Background and Purpose- Delayed cerebral infarction (DCI) is an important cause of morbidity and mortality in patients with aneurysmal subarachnoid hemorrhage (aSAH). Stereotactic catheter ventriculocisternostomy (STX-VCS) and fibrinolytic/spasmolytic lavage is a new method for DCI prevention. Here, we assess the effects of implementing STX-VCS in an unselected aSAH patient population of a tertiary referral center. Methods- Retrospective cohort study of all consecutive aSAH patients admitted to a neurosurgical referral center during a 7-year period (April 2012 to April 2019). Midterm STX-VCS was introduced and offered to patients at high risk for DCI. We compared the incidence and burden of DCI, neurological outcome, and the use of induced hypertension and endovascular rescue therapy in this consecutive aSAH population 3.5 years before versus 3.5 years after STX-VCS became available. Results- Four hundred thirty-six consecutive patients were included: 222 BEFORE and 214 AFTER. Fifty-seven of 214 (27%) patients received STX-VCS. Stereotactic procedures resulted in one (2%) subdural hematoma. Favorable neurological outcome at 6 months occurred in 118 (53%) patients BEFORE and 139 (65%) patients AFTER (relative risk, 0.79 [95% CI, 0.66-0.95]). DCI occurred in 40 (18.0%) patients BEFORE and 17 (7.9%) patients AFTER (relative risk, 0.68 [95% CI, 0.57-0.86]), and total DCI volumes were 8933 (100%) and 3329 mL (36%), respectively. Induced hypertension was used in 97 (44%) and 30 (15%) patients, respectively (relative risk, 0.55 [95% CI, 0.46-0.65]). Thirty (13.5%) patients BEFORE versus 5 (2.3%) patients AFTER underwent endovascular rescue therapies (relative risk, 0.17 [95% CI, 0.07-0.42]). Conclusions- Selecting high-risk patients for STX-VCS reduced the DCI incidence, burden, and related mortality in a consecutive aSAH patient population. This was associated with an improved neurological outcome.

Minimally invasive resection of spinal hemangioblastoma: feasibility and clinical results in a series of 18 patients.

OBJECTIVE: Hemangioblastomas are benign, highly vascularized tumors that can occur sporadically or as part of von Hippel-Lindau (VHL) disease. Traditionally, spinal hemangioblastomas have been surgically treated via an open approach. In recent years, however, minimally invasive techniques using tubular retractors have been increasingly applied in spine surgery. Such procedures involve less tissue trauma but are also particularly demanding for the surgeon, especially in cases of highly vascular tumors such as hemangioblastomas. The object of this study was to evaluate the safety and efficacy of minimally invasive resection of selected spinal hemangioblastomas. METHODS: The authors conducted a retrospective single-center study of all patients who, between January 2010 and January 2018, had been operated on for spinal hemangioblastoma via a minimally invasive approach performed at the surgeon's discretion. The surgical technique is described and the pre- and postoperative neurological and imaging results were analyzed descriptively. The primary outcome was the postoperative compared to preoperative neurological condition (McCormick grade). The secondary outcomes were the extent of tumor resection and postoperative complications. RESULTS: Eighteen patients, 12 female and 6 male, harboring a total of 19 spinal hemangioblastomas underwent surgery in the study period. Seventeen patients had stable neurological findings with stable or improved McCormick grades (94.5%) at a mean of 4.3 months after surgery. One (5.5%) of the 18 patients developed progressive neurological symptoms with a worsened McCormick grade that did not improve in the long-term follow-up. Sixteen of the 18 patients had VHL disease, whereas 2 patients had sporadic spinal hemangioblastomas. In all patients, postoperative MRI showed complete resection of the tumors. No other surgery-related perioperative or postoperative complications were recorded. CONCLUSIONS: A minimally invasive approach for the resection of selected spinal hemangioblastomas is safe and allows complete tumor resection with good clinical results in experienced hands.

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.