Surgical treatment of symptomatic pineal cysts without hydrocephalus-meta-analysis of the published literature.

BACKGROUND: To examine published data and assess evidence relating to safety and efficacy of surgical management of symptomatic pineal cysts without hydrocephalus (nhSPC), we performed a systematic review of the literature and meta-analysis. METHODS: Following the PRISMA guidelines, we searched Pubmed and SCOPUS for all reports with the query 'Pineal Cyst' AND 'Surgery' as of March 2021, without constraints on study design, publication year or status (PROSPERO_CRD:42,021,242,517). Assessment of 1537 hits identified 26 reports that met inclusion and exclusion criteria. RESULTS: All 26 input studies were either case reports or single-centre retrospective cohorts. The majority of outcome data were derived from routine physician-recorded notes. A total of 294 patients with surgically managed nhSPC were identified. Demographics: Mean age was 29 (range: 4-63) with 77% females. Mean cyst size was 15 mm (5-35). Supracerebellar-infratentorial approach was adopted in 90% of cases, occipital-transtentorial in 9%, and was not reported in 1%. Most patients were managed by cyst resection (96%), and the remainder by fenestration. Mean post-operative follow-up was 35 months (0-228). PRESENTATION: Headache was the commonest symptom (87%), followed by visual (54%), nausea/vomit (34%) and vertigo/dizziness (31%). Other symptoms included focal neurology (25%), sleep disturbance (17%), cognitive impairment (16%), loss of consciousness (11%), gait disturbance (11%), fatigue (10%), 'psychiatric' (2%) and seizures (1%). Mean number of symptoms reported at presentation was 3 (0-9). OUTCOMES: Improvement rate was 93% (to minimise reporting bias only consecutive cases from cohort studies were considered, N = 280) and was independent of presentation. Predictors of better outcomes were large cyst size (OR = 5.76; 95% CI: 1.74-19.02) and resection over fenestration (OR = 12.64; 3.07-52.01). Age predicted worse outcomes (OR = 0.95; 0.91-0.99). Overall complication rate was 17% and this was independent of any patient characteristics. Complications with long-term consequences occurred in 10 cases (3.6%): visual disturbance (3), chronic incisional pain (2), sensory disturbance (1), fatigue (1), cervicalgia (1), cerebellar stroke (1) and mortality due to myocardial infarction (1). CONCLUSIONS: Although the results support the role of surgery in the management of nhSPCs, they have to be interpreted with a great deal of caution as the current evidence is limited, consisting only of case reports and retrospective surgical series. Inherent to such studies are inhomogeneity and incompleteness of data, selection bias and bias related to assessment of outcome carried out by the treating surgeon in the majority of cases. Prospective studies with patient-reported and objective outcome assessment are needed to provide higher level of evidence.

Cerebral embolization associated with parenchymal seeding of the left atrial myxoma: Potential role of interleukin-6 and matrix metalloproteinases.

Systemic embolization has been reported in up to 40% of patients with left atrial myxoma, half of them with cerebral involvement. However, development of intracerebral embolization associated with parenchymal seeding of the myxoma emboli is an extremely rare complication, with only 36 histologically diagnosed cases reported in the published literature. We describe a 69-year-old woman who arrived at the emergency service with hemiparesis associated with drug-resistant epilepsy and a medical history of resection of a left atrial myxoma 10 months previously. Cranial computed tomography revealed multiple large lesions of heterogeneous density and cystic components in the occipital lobes and posterior fossa parenchyma. Histopathological analyses after stereotactic biopsy of the occipital lesion revealed infiltrative myxoma cells with benign histological findings and uniform expression of calretinin similar to that of the primary cardiac myxoma. Additional immunohistochemical studies confirmed brain parenchymal seeding of the myxoma cells with strong expression of interleukin-6 (IL-6) and focal expression of matrix metalloproteinases-2 (MMP-2). Here, we discuss the clinicopathological features of intracerebral embolization of left atrial myxomas associated with progressive parenchymal seeding of the tumor emboli and the potential pathogenic role of IL-6 and MMPs.

Long-term survival outcomes of pineal region gliomas.

PURPOSE: Surgical series of pineal region gliomas are rarely available. Whereas it is a general assumption that the extent of surgical resection correlates with survival outcomes of intracranial gliomas; the impact of the microsurgical resection on the long-term outcomes of pineal gliomas has been questioned. We present a surgical series of pineal region gliomas with focus on the survival outcome analysis. METHODS: 17 histologically confirmed pineal region glioma patients classified as diffuse and non-diffuse gliomas were retrospectively analyzed. A detailed description of the series was followed by regression models to identify predictors of clinical outcomes. Uni- a multivariate survival analysis was performed to determine independent predictors of mortality. RESULTS: Although the number of treated patients was small, only WHO grade histopathology remained significant (p = 0.02) after multivariate survival analysis with extent of resection, age, tumor volume, and preoperative functional status. The extent of the surgical resection did not correlate with the disease survival rates of non-diffuse (p = 1), diffuse (p = 0.2), nor all gliomas (p = 0.6). 15 of 17 patients underwent gross total (nine patients) or subtotal resection. The preoperative functional status of the patients showed overall improvement on the immediate (p < 0.001) and long-term (p = 0.03) follow-up after 106 (3 - 324) months. CONCLUSION: The extent of the surgical resection does not seem to significantly impact on the survival outcomes of pineal region gliomas. Thus, genotype and molecular features may essentially affect the outcome. Further research on the field is required.

Systematic review of pineal cysts surgery in pediatric patients.

INTRODUCTION: We present a consecutive case series and a systematic review of surgically treated pediatric PCs. We hypothesized that the symptomatic PC is a progressive disease with hydrocephalus at its last stage. We also propose that PC microsurgery is associated with better postoperative outcomes compared to other treatments. METHODS: The systematic review was conducted in PubMed and Scopus. No clinical study on pediatric PC patients was available. We performed a comprehensive evaluation of the available individual patient data of 43 (22 case reports and 21 observational series) articles. RESULTS: The review included 109 patients (72% females). Ten-year-old or younger patients harbored smaller PC sizes compared to older patients (p < 0.01). The pediatric PCs operated on appeared to represent a progressive disease, which started with unspecific symptoms with a mean cyst diameter of 14.5 mm, and progressed to visual impairment with a mean cyst diameter of 17.8 mm, and hydrocephalus with a mean cyst diameter of 23.5 mm in the final stages of disease (p < 0.001). Additionally, 96% of patients saw an improvement in their symptoms or became asymptomatic after surgery. PC microsurgery linked with superior gross total resection compared to endoscopic and stereotactic procedures (p < 0.001). CONCLUSIONS: Surgically treated pediatric PCs appear to behave as a progressive disease, which starts with cyst diameters of approximately 15 mm and develops with acute or progressive hydrocephalus at the final stage. PC microneurosurgery appears to be associated with a more complete surgical resection compared to other procedures.

Pineal Gland Tumor Microenvironment.

A wide and heterogeneous variety of tumors develop from the pineal gland. Pineal parenchymal tumors, germ cell tumors, and glial tumors represent most of them. The molecular profiles and tumor microenvironment play a key role in the development and progression of pineal gland tumors. Consequently, they represent important factors that may determine the efficacy of the different treatment modalities and the clinical outcome. Current literature is scarce regarding the microenvironment research of pineal gland tumors. Here, we review the cellular and molecular profile of the pineal gland tumor microenvironment.

"Dirty coagulation" technique as an alternative to microclips for control of bleeding from deep feeders during brain arteriovenous malformation surgery.

BACKGROUND: Meticulous haemostasis is one of the most important factors during microneurosurgical resection of brain arteriovenous malformation (AVM). Controlling major arterial feeders and draining veins with clips and bipolar coagulation are well-established techniques, while managing with bleeding from deep tiny vessels still proves to be challenging. This technical note describes a technique used by the senior author in AVM surgery for last 20 years in dealing with the issue highlighted. METHOD: "Dirty coagulation" is a technique of bipolar coagulation of small feeders carried out together with a thin layer of brain tissue that surrounds these fragile vessels. The senior author uses this technique for achieving permanent haemostasis predominantly in large and/or deep-seated AVMs. To illustrate the efficacy of this technique, we retrospectively reviewed the outcome of Spetzler-Martin (SM) grade III-V AVMs resected by the senior author over the last 5 years (2010-2015). RESULTS: Thirty-five cases of AVM surgeries (14 SM grade III, 15 SM grade IV and 6 SM grade V) in this 5-year period were analysed. No postoperative intracranial haemorrhage was encountered as a result of bleeding from the deep feeders. Postoperative angiograms showed complete resection of all AVMs, except in two cases (SM grade V and grade III). CONCLUSIONS: "Dirty coagulation" provides an effective way to secure haemostasis from deep tiny feeders. This cost-effective method could be successfully used for achieving permanent haemostasis and thereby decreasing postoperative haemorrhage in AVM surgery.

Prognostic value of scales for aneurysmal subarachnoid hemorrhage: Report of a reference center in Peru.

INTRODUCTION: Multiple scales have been designed to stratify the severity and predict the prognosis in the initial evaluation of patients with aneurysmal subarachnoid hemorrhage (aSAH). Our study aimed to validate the most commonly used prognostic scales for aSAH in our population: Hunt-Hess, modified Hunt-Hess, World Federation of Neurosurgical Societies (WFNS), Prognosis on Admission of Aneurysmal Subarachnoid Hemorrhage (PAASH), and Barrow Aneurysm Institute (BAI) scales. METHODS: This study includes all aSAH cases treated at our institution between June 2019 and December 2020. We developed a retrospective cohort by reviewing medical records and radiologic images performed during hospitalization. The outcome was evaluated using the modified Rankin scale (mRS). It was defined as a poor outcome (mRS 4-5) and mortality (mRS 6). The ROC curves and the area under the curve (AUC) of each of the prognostic scales were calculated to evaluate their prognostic prediction capacity. RESULTS: A total of 142 patients were diagnosed with aSAH. A poor outcome occurred in 52.1% of the patients, whereas mortality was 27.5%. The AUC of the scales studied was similar and no significant difference was found between them for predicting a poor outcome (P = .709) or mortality (P = .715). CONCLUSION: We determined that the prognostic scales for aSAH had a similar predictive value for poor clinical outcomes and mortality in our institution, with no significant difference. Thus, we recommend the most simple and well-known scale used institutionally.

Vascular Lesions of the Pineal Region: A Comprehensive Review of the Therapeutic Options.

OBJECTIVE: Vascular lesions of the pineal region comprise aneurysms of the pineal region, arteriovenous malformations, cavernous malformations, and vein of Galen malformations. In the present report, we have offered an extensive review of each vascular pineal region lesion. METHODS: We performed an extensive literature review, focusing on the current therapeutic options available for the different vascular lesions of the pineal region. RESULTS: Vascular lesions of the pineal region are rare. Microneurosurgery remains a valid treatment of cavernomas, arteriovenous malformations, and aneurysms. Endovascular treatments seem to be the first option for the vein of Galen malformations, followed by microneurosurgery. Radiosurgery seems beneficial for small-size arteriovenous malformations. Complex and large vascular lesions will require a combination of multiple treatments. CONCLUSIONS: Vascular lesions of the pineal region are complex, uncommon diseases. Thus, definitive therapeutic modalities for these lesions require further research.

Management of Obstructive Hydrocephalus Associated with Pineal Region Cysts and Tumors and Its Implication in Long-Term Outcome.

BACKGROUND: Different treatment options have been proposed for obstructive hydrocephalus associated with pineal lesions. We discuss the obstructive hydrocephalus management associated with pineal region tumors and cysts in Helsinki Neurosurgery. METHODS: In this article, hydrocephalus treatment by tumor-cyst removal (n = 40), shunt surgery (n = 25), and endoscopic ventriculostomies (n = 3) is evaluated in 68 patients with obstructive hydrocephalus among 136 patients with pineal region tumor and cyst. Multivariate statistical analysis was followed by univariate and multivariate regression models of last functional status, last tumor-free imaging, and disease-specific mortality of the study population. RESULTS: Preoperative hydrocephalus was linked to higher World Health Organization tumor grades, poor functional status, higher mortality, and incomplete resection of pineal region cysts and tumors. Preoperative hydrocephalus remained a predictor of poor last functional status after multivariate regression. Pineal lesion removal with the posterior third ventricle opening as primary hydrocephalus treatment resulted in better last functional status, fewer postoperative shunts, fewer hydrocephalus-related procedures, and fewer postoperative infections than in the shunt-treatment group. Multivariate regression analysis linked higher World Health Organization tumor grade, poor immediate functional status, postoperative complications, and incomplete surgical resection as independent predictors of disease mortality in patients with hydrocephalus. Same variables (except immediate modified Rankin Scale score) and higher number of shunt surgeries became independent predictors of poor last functional status at multivariate analysis. Incomplete resection was the only independent predictor of tumor-free magnetic resonance imaging at the last evaluation. CONCLUSIONS: Direct removal of pineal lesions with the opening of the posterior third ventricle could represent effective and reliable management of the associated obstructive hydrocephalus. Further research is required to generalize our inferences.

Foreign body granuloma reaction after endovascular therapy of an unruptured right frontal arteriovenous malformation.

Foreign body reactions after endovascular procedures for brain arteriovenous malformations are extremely rare. We report the case of a cerebral foreign body granuloma reaction after embolization of a frontal arteriovenous malformation with Onyx. A previously treated 36-year-old man underwent re-embolization of a residual and recurrent unruptured right frontal vascular malformation with Onyx. The post-procedural imaging revealed a right frontotemporal heterogeneously enhancing expansive lesion associated with a residual malformation. Following microsurgical resection, the histopathological examination of the expansive lesion revealed basophilic foreign body like deposits adjacent to multi-nucleated giant cells, highly compatible with cerebral foreign body granulomas reaction to Onyx. The clinical and radiological follow-up of the patient was favorable after complete resection of the lesions.

Functional status of surgically treated pineal cyst patients.

BACKGROUND: Microsurgical removal represents a well-accepted treatment option for symptomatic benign pineal cysts (PCs). However, very few studies have quantitatively evaluated the functional status of surgically treated PC patients. METHODS: A detailed analysis of preoperative, immediate postoperative, and long-term clinical and radiological characteristics was performed. The functional status of the patients was categorized using the modified Rankin scale (mRS) and the Chicago Chiari Outcome Scale (CCOS). In addition, a comparative analysis between pediatric and adult patients with PCs was carried out. RESULTS: Overall, pediatric patients experienced better long-term mRS scores than adults. The differences between the pre-, the immediate post-, and the last postoperative mRS of the patients were statistically significant for the total population (P < 0.001). All patients obtained a CCOS of 11 or more, which reflects a good/optimal result after microneurosurgery. The type of the surgical approach was independently associated with the postoperative complications (P < 0.01), more frequently reported with the midline supracerebellar infratentorial (SCIT) approach than with its paramedian modification. CONCLUSION: The functional status of properly selected symptomatic patients with PCs may improve significantly after their surgical management through a paramedian SCIT approach in sitting position.

Midline and Paramedian Supracerebellar Infratentorial Approach to The Pineal Region: A Comparative Clinical Study in 112 Patients.

OBJECTIVE: The midline supracerebellar infratentorial (SCIT) approach and its paramedian development are commonly used for dealing with pineal lesions. Comparative clinical studies are lacking, however. We aim to establish the better performance of the paramedian SCIT approach in terms of clinical safety in surgically treated pineal cysts and pineal region tumors. Procedural functionality and effectiveness have been also analyzed. METHODS: A comparative analysis of clinical, radiologic, pathologic, and surgical features, and outcome was performed between 55 midline and 57 paramedian SCIT approaches that were exclusively performed in 112 patients (57 pineal cysts and 55 tumors of the pineal region) operated in sitting position by a single surgeon. Information was retrieved from hospital records and microsurgical videos. RESULTS: The paramedian SCIT approach linked with fewer postoperative complications (odds ratio [OR]: 0.40) and fewer approach-related complications (OR: 0.28) than the midline SCIT approach. The SCIT paramedian approach was achieved in a shorter time, by a smaller bone flap, and with fewer complex procedural steps than the midline approach. The SCIT paramedian approach did not require the opening of the falx cerebelli, midline cerebellar retraction, section of the midline cerebellar draining veins, nor wide opening of the dura. Gross total resection, size of the lesion, microsurgical time for removal, histopathological diagnosis and postoperative outcome were statistically similar in both groups. CONCLUSIONS: The SCIT approach represents a safer and more functional approach for the removal of cysts and tumors of the pineal region than the classic midline approach, while maintaining the same effectiveness.

Unedited microneurosurgery of a pineal region neuroepithelial cyst.

BACKGROUND: Neuroepithelial cysts are benign, well-circumscribed, nonenhancing CSF-like masses that might virtually present in any intracranial location. Common locations are the frontal lobe, thalamus, midbrain and pons, vermis, the lateral and fourth ventricles, and the choroid fissure (Choroid fissure cysts). Usually asymptomatic, cysts in the posterior fossa have been reported to cause cranial nerve palsies, focal brainstem dysfunction, and hydrocephalus. Supratentorial cysts might cause seizures or focal motor and/or sensory deficits. Histopathological examination reveals that neuroepithelial cysts are lined by ependymal (columnar epithelium) or choroid plexus cells (low cuboidal epithelium). The differential diagnosis includes enlarged perivascular spaces, infectious cyst-neurocysticercosis, porencephalic cyst, and arachnoid cyst. CASE DESCRIPTION: A patient with a symptomatic histologically confirmed pineal region neuroepithelial cyst underwent park bench position and a right supracerebellar infratentorial approach. The pineal region was accessed over the right cerebellar hemisphere and the lesion was identified after a lateral opening of the quadrigeminal cistern. After a careful dissection of the lesion, the cyst was pulled out with long ring microforceps and long sharp bipolar forceps; both assisted by a thumb-regulated suction tube. A complete lesion was removed in a piece and meticulous attention was paid to any bleeding securing complete hemostasis of the surgical site. The postoperative course was uneventful. The patient underwent rehabilitation without recurrence of the lesion. CONCLUSION: This unedited video offers all detailed aspects that a neurosurgeon as the senior author JH considers essential when performing an efficient and safe surgery into the pineal region for this very rarely documented pineal region neuroepithelial cyst. VIDEOLINK: http://surgicalneurologyint.com/videogallery/pineal-cyst-4.

Are Fetal-Type Posterior Cerebral Arteries Associated With an Increased Risk of Posterior Communicating Artery Aneurysms?

BACKGROUND: Fetal-type posterior cerebral arteries (F-PCAs) might result in alterations in hemodynamic flow patterns and may predispose an individual to an increased risk of posterior communicating artery aneurysms (PCoAAs). OBJECTIVE: To determine the association between PCoAAs and the presence of ipsilateral F-PCAs. METHODS: We retrospectively reviewed the radiographic findings from 185 patients harboring 199 PCoAAs that were treated at our institution between 2005 and 2015. Our study population consisted of 4 cohorts: (A) patients with 171 internal carotid arteries (ICAs) harboring unilateral PCoAAs; (B) 171 unaffected ICAs in the same patients from the first group; (C) 28 ICAs of 14 patients with bilateral PCoAAs; and (D) 180 ICAs of 90 patients with aneurysms in other locations. We then determined the presence of ipsilateral F-PCAs and recorded all aneurysm characteristics. RESULTS: Group A had the highest prevalence of F-PCAs (42%) compared to 19% in group B, 3% in group C, and 14% in group D (odds ratio A : B = 3.041; A : C = 19.626; and A : D = 4.308; P < .001). PCoAAs were associated with larger diameters of the posterior communicating arteries (median value 1.05 vs 0.86 mm; P = .001). The presence of F-PCAs was associated with larger sizes of the aneurysm necks (median value 3.3 vs 3.0 mm; P = .02). CONCLUSION: PCoAAs were associated with a higher prevalence of ipsilateral F-PCAs. This variant was associated with larger sizes of the aneurysm necks but was not associated with the sizes of the aneurysm domes or with their rupture statuses.

Pineal Parenchymal Tumors of Intermediate Differentiation: A long-Term Follow-Up Study in Helsinki Neurosurgery.

BACKGROUND: Pineal parenchymal tumors of intermediate differentiation (PPTIDs) are rare lesions with particular features compared with other pineal parenchymal tumors. METHODS: We present a retrospective review of patients with histologically confirmed PPTIDs who were operated on in our department between 1997 and 2015. A demographic analysis and an evaluation of preoperative status, surgical treatment, as well as immediate and long-term clinical and radiologic outcomes were conducted. RESULTS: Fifteen patients with PPTIDs were operated on between 1997 and 2015. Gross total removal was achieved in 11 cases; 2 patients underwent near-total resection, 1 partial resection, and 1 received brachytherapy after an endoscopic biopsy. Nine patients required external radiation therapy (4 due to a pleomorphic histology of their lesion including pineoblastoma features in 3 of them; 3 after a subtotal resection; and 2 for tumor recurrence). No patient received chemotherapy. The survival rate of our patients was 57.1% at a mean follow-up of 137.2 ± 77.6 months (39-248 months). CONCLUSIONS: A proper multidisciplinary management of PPTIDs based on a gross total removal of the lesion, and an adjuvant radiotherapy in selected cases, may improve the overall survival of these aggressive tumors.

The microsurgical management of benign pineal cysts: Helsinki experience in 60 cases.

BACKGROUND: Microsurgical resection represents a well-accepted management option for symptomatic benign pineal cysts. Symptoms such as a headache, hydrocephalus, and visual deficiency are typically associated with pineal cysts. However, more recent studies reported over the past years have characterized additional symptoms as a part of the clinical manifestation of this disease and represent additional indications for intervention. METHODS: We present a retrospective review of patients with histologically confirmed benign pineal cysts that were operated on in our department between 1997 and 2015. A demographic analysis, evaluation of preoperative status, surgical treatment, as well as immediate and long-term clinical and radiological outcomes were conducted. RESULTS: A total of 60 patients with benign pineal cysts underwent surgery between 1997 and 2015. Gross total resection was achieved in 58 cases. All patients except one improved in their clinical status or had made a full recovery at the time of the last follow-up. The key steps for surgical resection of pineal cysts are reported, based on an analysis of representative surgical videos. CONCLUSIONS: We describe in this paper one of the largest series of microsurgically treated pineal cysts. In our opinion, judicious microsurgery remains the most suitable technique to effectively deal with this disease.

Extent of Resection and Long-Term Survival of Pineal Region Tumors in Helsinki Neurosurgery.

BACKGROUND: Pineal region tumors represent challenging surgical lesions with wide ranges of survival reported in different surgical series. In this article, we emphasize the role of complete microsurgical resection (CMR) to obtain a favorable long-term outcome of pineal region tumors. METHODS: We report a retrospective study of pineal region tumors operated on in Helsinki Neurosurgery between 1997 and 2015. Information was obtained from the hospital records, and an evaluation of the Finnish population register was conducted in July 2018 to determine the current status of the patients. RESULTS: A total of 76 pineal region tumors were operated on. The survival was 62% at a mean follow-up of 125 ± 105 months (range, 0-588 months), and the disease-related mortality was limited to 14 patients (18.4%). Up to July 2018, 29 patients had died. Two patients died 1 and 3 months after surgery of delayed thalamic infarctions, 12 patients of disease progression, and 15 had non-disease-related deaths. Only 1 patient was lost in the long-term follow-up. Ten of 14 disease-related deaths occurred during the first 5 years of follow-up: 5 diffuse gliomas, 3 germ cell tumors, 1 grade II-III pineal parenchymal tumor of intermediate differentiation, and 1 meningioma. CMR was linked to better tumor-free survival and long-term survival, with the exception of diffuse gliomas. CONCLUSIONS: CMR, in the setting of a multidisciplinary management of pineal region tumors, correlates with favorable survival and with minimal mortality. Surgically treated grade II-IV gliomas constitute a particular group with high mortality within the first 5 years independently of the microsurgical resection.

One burr-hole craniotomy: Suboccipital midline approach to the fourth ventricle in Helsinki neurosurgery.

BACKGROUND: In this video-abstract, we present one burr-hole craniotomy for the standard suboccipital midline approach developed in Helsinki neurosurgery for the microsurgical management of forth ventricle lesions, distal posterior inferior cerebellar artery aneurysms, and tumoral and vascular lesions of the vermis, cisterna magna region, and posterior brainstem as well. CASE DESCRIPTION: We prefer to position the patient in sitting praying position. A midline straight single-layer incision starts on the inion and extends caudally toward the level of C2. The muscles are divided with diathermia along the occipital bone. Three curved retractors, two upward and one downward, provide a wide clean space for the craniotomy. Finger palpation and blunt dissection with cottonoids balls provide identification of the foramen magnum and the spinous process of C1. A burr-hole is made 1 cm lateral and below the level of the transverse sinus. After the detachment of the dura with a curved angled dissector, two cuts from both sites of the burr-hole are made with the craniotome. In case of an adherent dura particularly present in elderly patients, a long blunt flexible dissector (yasargil dissector) is used for the detachment of the bone from the dura. A craniotomy around the midline overlying the occipital sinus and the falx cerebelli is performed to expose medial aspects of cerebellar tonsils, the medulla oblongata, and the occipital sinus. Special care should be taken to avoid damaging the vertebral artery and the epidural sinuses running at the foramen magnum. A few drill holes are made for tack-up sutures. After a craniocervical-based opening of the dura, the fourth ventricle is accessed directly by telovelar route. CONCLUSION: The described one burr-hole craniotomy may represent the more efficient manner for performing the suboccipital midline approach to the fourth ventricle. VIDEOLINK: http://surgicalneurologyint.com/videogallery/suboccipital-midline-approach/.

One burr-hole craniotomy: Modified presigmoid approach in Helsinki Neurosurgery.

BACKGROUND: In this video abstract, we present a one burr-hole craniotomy for a modified presigmoid approach developed in Helsinki Neurosurgery to access the space extended to both middle and posterior fossa. Thus, indications for this approach are lesions that extend to both middle and posterior fossa, petroclival tumors, basilar tip aneurysms located extremely low below the posterior clinoid process, trunk basilar aneurysms, and bypass procedures from the P2 segment of the posterior cerebral artery. The procedure is composed by three stages: a temporal and presigmoid craniotomy, a partial petromastoidectomy, and the dura opening with section of the superior petrosal sinus (SPS) and the tentorium. Even though some risks related to the opening of the mastoid cells or cut of the SPS may exist, benefits of this optimized craniotomy are higher compared with the complications. CASE DESCRIPTION: The patient with a giant petroclival meningioma is placed in park bench position and spinal drainage is inserted. Skin incision starts in front of the ear curve going to 1 inch behind the mastoid line. Strong retraction with hooks keeps a clean space for the craniotomy. Hemostatic Raney clips are placed at the superior border of the skin flap. A burr-hole is made at the most cranial part of the temporal bone. After the detachment of the dura with long flexible blunt dissectors, the craniotomy is performed to expose the sigmoid sinus, the SPS and the dura of the inferior temporal lobe, and the floor of the middle fossa. Aiming to access the posterior fossa by a presigmoid route, a partial petromastoidectomy is performed preserving the semicircular canals. Few drill holes are made for tack-up sutures. Once we properly reach the dura of the middle and posterior fossa, dura of the temporal lobe and later, the presigmoid dura are opened joining at the level of the SPS. The SPS, which is running over the petrous bone between the posterior and the middle fossa, is coagulated, ligated, and cut. After SPS is sectioned, the tentorium is cut anterior to the drainage of vein of Labbé and posterior to the deep tentorial insertion of the fourth nerve. Finally, special care should be taken to seal the opened mastoid cells with muscle and glue, and for the hermetic dura closure using pericranium or temporal muscle aponeurosis. CONCLUSION: The described one burr-hole craniotomy may represent the more efficient approach for the management of the deep and hardly accessible lesions extended to both middle and posterior fossa. VIDEOLINK: http://surgicalneurologyint.com/videogallery/presigmoid-approach-craniotomy-lt.