Infratentorial Approach Research Articles

Surgical and Peri-Operative Considerations for Brain Metastases.

IntroductionBrain metastases are the most common brain tumors in adults, whose management remains nuanced. Improved understanding of risk factors for surgical complications and mortality may guide treatment decisions.MethodsA nationwide, multicenter analysis was conducted with a retrospective cohort. Adult patients in the 2012-2015 American College of Surgeons National Surgical Quality Improvement Project (ACS NSQIP) databases who received a craniotomy for resection of brain metastasis were included.Results3500 cases were analyzed, of which 17% were considered frail and 24% were infratentorial. The most common 30-day medical complications were venous thromboembolism (3%, median time-to-event [TTE] 4.5 days), pneumonia (4%, median TTE 6 days), and urinary tract infections (2%, median TTE 5 days). Reoperation and unplanned readmission occurred in 5% and 12% of patients, respectively. Infratentorial approach and frailty were associated with reoperation before discharge (OR 2.0 for both; p=0.01 and p=0.03 respectively), but not after discharge. Infratentorial approaches conferred heightened risk for readmission for hydrocephalus (OR 5.1, p=0.02) and reoperation for cerebrospinal fluid diversion (OR 7.1, p<0.001).Overall 30-day mortality was 4%, with nearly three-quarters occurring after discharge. Pre-frailty and frailty were associated with increased odds for post-discharge mortality (OR 1.7 and 2.7, p<0.05), but not pre-discharge mortality. We developed a model to identify pre-/peri-operative variables associated with death, including frailty, thrombocytopenia, and high American Society of Anesthesiologists score (AUROC 0.75).ConclusionsOptimization of metrics contributing to patient frailty and heightened surveillance in patients with infratentorial metastases may be considered in the peri-operative period.

Development of Integrated 3-Dimensional Computer Graphics Human Head Model

Understanding the complex anatomy of neurostructures is very important in various stages of medical education, from medical students to experienced neurosurgeons, and, ultimately, for the knowledge of human beings. To develop an interactive computer graphics (CG) anatomic head model and present the current progress. Based on the prior head 3-dimensional CG (3DCG) polygon model, 23 additional published papers and textbooks were consulted, and 2 neurosurgeons and 1 CG technician performed revision and additional polygon modeling. Three independent neurosurgeons scored the clear visibility of anatomic structures relevant to neurosurgical procedures (anterior petrosal and supracerebellar infratentorial approaches) in the integrated 3DCG model (i model) and patients' radiological images (PRIs) such as those obtained from computed tomography, magnetic resonance imaging, and angiography. The i model consisted of 1155 parts (.stl format), with a total of 313 763 375 polygons, including 10 times more information than the foundation model. The i model was able to illustrate complex and minute neuroanatomic structures that PRIs could not as well as extracranial structures such as paranasal sinuses. Our subjective analysis showed that the i model had better clear visibility scores than PRIs, particularly in minute nerves, vasculatures, and dural structures. The i model more clearly illustrates minute anatomic structures than PRIs and uniquely illustrates nuclei and fibers that radiological images do not. The i model complements cadaveric dissection by increasing accessibility according to spatial, financial, ethical, and social aspects and can contribute to future medical education.

Selection of surgical approach for cerebellar hemangioblastomas based on venous drainage patterns.

Cerebellar hemangioblastomas remain surgically challenging because of the narrow, deep surgical corridors and tumor hypervascularity. Various surgical approaches are used according to the location, but optimal approaches have not been established. We propose a system of surgical approaches based on the venous drainage systems to facilitate surgical planning and achieve acceptable neurological outcomes. Cerebellar hemangioblastomas were divided into five types based on the main drainage systems: suboccipital hemangioblastomas draining to the transverse sinus (TS) or torcula, tentorial hemangioblastomas draining to the tentorialsinus orstraight sinus, petrosal hemangioblastomas draining to the superior petrosal sinus (SPS), quadrigeminal hemangioblastomas draining to the galenic system, and tonsillar hemangioblastomas draining to the TS or torcula in conjunction with jugular bulb or SPS. Microsurgical approaches and patient outcome were retrospectively reviewed according to this classification. This study included 17 patients who underwent 21 operations for resection of 19 cerebellar hemangioblastomas, classified into 9 suboccipital, 4 tentorial, 2 petrosal, 2 quadrigeminal, and 2 tonsillar. Standard suboccipital craniotomies were utilized for suboccipital hemangioblastomas, the occipital transtentorial approach (OTA), and supracerebellar infratentorial approach for tentorial hemangioblastomas, the retrosigmoid approach for petrosal hemangioblastomas, OTA for quadrigeminal hemangioblastomas, and midline suboccipital approach for tonsillar hemangioblastomas. Gross total resection was achieved in all patients except one. Two patients with large hemangioblastomas (tonsillar and quadrigeminal) required second-stage operation which finally achieved gross total removal. No single approach had a significantly higher incidence of postoperative neurological deficits. Selection of the optimum surgical approach for cerebellar hemangioblastomas was successful based on the main drainage systems. Understanding of tumor growth and extension with respect to the venous drainage system is critical to select the appropriate surgical approach.

Technical Note: Extreme Lateral Supracerebellar Approach for Resection of Superior Cerebellar Peduncle Arteriovenous Malformations.

The surgical approaches to the region of the cerebello-mesencephalic sulcus and superior cerebellar peduncle (SCP) remain a neurosurgical challenge. To present the use of the extreme lateral supracerebellar infratentorial (SC-IT) approach to treat arteriovenous malformations (AVMs) of the SCP, which is a different entity compared to brainstem AVMs. We treated 4 patients with SCP AVMs in the last 5 yr at our institution. The mean age was 49.7 yr. The average nidus size was 2.12 cm. Of those, 3 patients presented with hemorrhage and 1 with headache and tinnitus. Extreme lateral SC-IT approach was used in all cases. Complete resection was achieved in all cases as verified with postoperative angiogram. In 1 case, intraoperative rupture with intraventricular hemorrhage was encountered, and the patient required temporary external ventricular drainage. There was no permanent complication or neurological deficit. The modified Rankin Scale (at discharge or follow-up) was less than 2 in all cases. The AVMs located primarily in the SCP are distinct compared to brainstem AVMs, and their management should be different. Extreme lateral SC-IT approach should be considered as a viable alternative surgical approach for resection of these AVMs, and excellent surgical results can be achieved.

Letter to the Editor Regarding “Extreme Lateral Supra Cerebellar Infratentorial Approach: Surgical Anatomy and Review of the Literature”

Letter to the Editor Regarding “Extreme Lateral Supra Cerebellar Infratentorial Approach: Surgical Anatomy and Review of the Literature”

In Reply to the Letter to the Editor Regarding “Extreme Lateral Supra Cerebellar Infratentorial Approach: Surgical Anatomy and Review of the Literature”

In Reply to the Letter to the Editor Regarding “Extreme Lateral Supra Cerebellar Infratentorial Approach: Surgical Anatomy and Review of the Literature”

Commentary: Virtual Reality Surgical Rehearsal and 2-Dimensional Operative Video of a Paramedian Supracerebellar Infratentorial Approach Endoscopic Resection of Pineocytoma: 2-Dimensional Operative Video.

Commentary: Virtual Reality Surgical Rehearsal and 2-Dimensional Operative Video of a Paramedian Supracerebellar Infratentorial Approach Endoscopic Resection of Pineocytoma: 2-Dimensional Operative Video.

Virtual Reality Surgical Rehearsal and 2-Dimensional Operative Video of a Paramedian Supracerebellar Infratentorial Approach Endoscopic Resection of Pineocytoma: 2-Dimensional Operative Video

An endoscopic "keyhole" approach to a deep-lying skull base lesion can be a daunting challenge. For the pineal region, the techniques for endoscopic resection of solid tumors in this location are also new.1,2 In such a situation, surgical rehearsal in virtual reality (VR) can significantly improve the surgeon's confidence.3 In this operative video, we demonstrate the use of VR in surgical planning and rehearsal to determine the best approach to a large, solid pineal tumor in a 46-yr-old patient. Using the patient's computed tomography angiography and magnetic resonance imaging, a VR model of his anatomy was created (SNAP VR360 version 3.8.0, Surgical Theater Inc, Cleveland, Ohio). VR rehearsal showed that, with the tumor tucked under the corpus callosum and cradled by the internal cerebral veins and veins of Rosenthal, a supratentorial approach would be suboptimal. Because of the steep angle of the patient's tentorium in the midline, a classic supracerebellar infratentorial (SCIT) approach would be challenging, and thus a paramedian variant of SCIT was chosen.4 For a right-handed surgeon, the left side was used, and the endoscope was docked at the extreme left, out of the main surgical corridor. Shown in the video, the endoscopic resection achieved a complete resection. The histopathological diagnosis was a pineocytoma. No adjuvant treatment is recommended. Given the rarity of pineocytoma,5 the novelty of endoscopic resection of solid tumors in the region, and the challenge of "keyhole" approaches to deep-lying targets, VR rehearsal facilitated the achievement of the surgical goal and avoided the morbidity of a more extensive exposure. Patient consent was obtained prior to the creation of the video and available on request. RHOTON images in the video are from The Rhoton Collection®.

Commentary: Virtual Reality Surgical Rehearsal and 2-Dimensional Operative Video of a Paramedian Supracerebellar Infratentorial Approach Endoscopic Resection of Pineocytoma: 2-Dimensional Operative Video.

Commentary: Virtual Reality Surgical Rehearsal and 2-Dimensional Operative Video of a Paramedian Supracerebellar Infratentorial Approach Endoscopic Resection of Pineocytoma: 2-Dimensional Operative Video.

Endoscopic-assisted microsurgical paramedian supracerebellar infratentorial approach to the posterior third ventricle. An anatomical morphometrical study and technical note with illustrative surgical cases

Endoscopic-assisted microsurgical paramedian supracerebellar infratentorial approach to the posterior third ventricle. An anatomical morphometrical study and technical note with illustrative surgical cases

Lateral supracerebellar infratentorial approach for a ruptured cerebellomesencephalic fissure arteriovenous malformation resection

In this surgical video, the authors present a case of a 24-year-old male patient who presented with sudden-onset headache and imbalance. On examination, he had a right-sided dysmetria and was otherwise neurologically intact. MRI showed a right cerebellar hematoma associated with multiple flow voids in the cerebellomesencephalic fissure and an enlarged lateral mesencephalic vein. Preoperative angiogram confirmed an arteriovenous malformation supplied by branches of the superior cerebellar artery. The patient underwent a lateral supracerebellar infratentorial approach for resection of the arteriovenous malformation (AVM). He recovered well from surgery and was discharged home on postoperative day 6. Postoperative angiogram confirmed complete AVM resection.The video can be found here: https://youtu.be/tY4Go2n7V80

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.

Contralateral sudden sensorineural hearing loss after resection of petroclival meningioma using combined supra- and infratentorial approach surgery

BackgroundContralateral sudden sensorineural hearing loss (SNHL) occurring after cerebellopontine surgery is rare. Presentation of petroclival meningioma followed by contralateral SNHL as a result of cerebellopontine surgery is quite uncommon, with only one case being previously reported. AimHere, a case of contralateral sensorineural hearing loss after supra- and infratentorial approach surgery is discussed including its incidence, potential mechanisms and treatment. Case reportA woman was presented with 6-months of double vision. Magnetic resonance imaging (MRI) revealed a tumor located at the apex of the left petrosalbone. The tumor was removed and pathological examination revealed a meningioma that could be treated with combined supra- and infratentorial approach surgery. Four days following surgery, the patient complained of contralateral hearing loss, which was confirmed using audiometry. Postoperative brain computed tomography (CT) and MRI revealed normal results. The patient was treated with heparin and acupuncture and her hearing gradually recovered over a 6-month period. ConclusionsChoosing the appropriate approach for cerebellopontine surgery is critical. During supra- and infratentorial approach surgery, there should be minimal damage to the veins, cochlea, labyrinth and CSF should be slowly released. Heparin and acupuncture may be therapeutic alternatives for patients who develop contralateral sensorineural hearing loss.

RESECCIÓN MICROQUIRURGICA DE UN CAVERNOMA PONTINO MEDIANTE UN ABORDAJE SUPRACEREBELOSO INFRATENTORIAL EXTREMO LATERAL

Introduction: Cavernomas on the posterolateral pontomesencephalic surface can be approached from an extreme lateral supracerebellar infratentorial corridor, although the theory is scarce. The brainstem has a dense concentration of nuclei and fibers that are responsible for a high rate of morbidity when treating brainstem lesions. The objective of this work is to demonstrate the safe microsurgical resection technique for the complete removal of a pontine cavernoma. Clinical Case: 27-year-old woman with a 5-month history of disease; characterized by headache, left facial paresis and right half body paresis. Magnetic resonance imaging (MRI) showed a hemorrhage in the middle cerebellar peduncle compatible with a ruptured cavernoma, initially receiving medical treatment. Subsequently, due to an increase in the motor deficit and the presence of keratopathy in the left eye, surgery was decided. A retromastoid craniotomy and an extreme lateral supracerebellar infratentorial approach were performed. A safe entry zone was identified and the cavernoma was completely excised. In the postoperative period, she did not present additional neurological deficit, being extubated at 24 hours, with a score on the Glasgow scale of 15 points. Postoperative brain tomography (CT) showed the absence of the cavernoma. Conclusion: The far lateral supracerebellar infratentorial approach is safe for the excision of cavernomas with a middle cerebellar peduncle. When combined with the significant reverse Trendelenburg position it results in minimal cerebellar retraction as the cerebellum descends with gravity. Keywords: Hemangioma, Cavernous, Pons, Middle Cerebellar Peduncle, Craniotomy (source: MeSH NLM)

How I do it: lateral supra-cerebellar infra-tentorial approach for P2-P3 junction cerebral aneurysms.

P2-P3 junction aneurysms are challenging to treat surgically because of their frequent complex morphology and their location deep in close proximity to the midbrain. The sub-temporal route requires significant retraction of the temporal lobe in addition to potential injury to the vein of Labbe. We describe the technique for treating such aneurysms via a lateral supra-cerebellar infra-tentorial (LSCIT) approach, which eliminates manipulation of the temporal lobe. Cadaveric dissection provided comprehensive understanding of relevant anatomy. Intraoperative video shows clipping of the aneurysm using a LSCIT approach. LSCIT approach allows safe clipping of P2-P3 aneurysms with minimal brain manipulation.

Endoscopic supracerebellar infratentorial approach to pineal and posterior third ventricle lesions in prone position with head extension: a technical note

ABSTRACT Objective The supracerebellar infratentorial (SCIT) approach is frequently used for the treatment of lesions in the pineal and posterior third ventricle region and can be performed in a sitting or prone position. We describe our experience with the purely endoscopic SCIT approach, using a prone position, with neck extension and head rotation. Methods We analysed all paediatric and adult patients operated on between July 2013 and January 2018 using the purely endoscopic SCIT approach. The surgical procedure was conducted through a paramedian subtorcular key-hole suboccipital craniotomy. The assistant held the endoscope and the surgeon used fine, long shaft instruments for bimanual tumour dissection. The prone position with head retroflexion allowed a gravity-aided enlargement of the anatomical surgical corridor between tentorium and cerebellum and enhanced venous blood drainage, similarly to the sitting or semi-sitting position, but with a decreased risk of air embolism. Results The approach allowed a complete removal of lesions located in the pineal region and in the posterior part of the third ventricle. Seven patients have been operated with this approach. All of them had the tumour completely removed. No permanent neurological deficits have been observed. Conclusions The endoscopic SCIT approach enables effective and safe removal of pineal and posterior third ventricle lesions, even of moderate dimensions (up to 3 cm). The endoscope guarantees a detailed view and illumination of the deep-seated structures. The tumour resection can be performed with bimanual use of microsurgical instruments.

Anatomic variations of the human falx cerebelli and its association with occipital venous sinuses

Purpose Human falx cerebelli is an important anatomical structure in regard to its relations with venous structures during infratentorial approach to reach cerebellar tumors, vascular malformations, traumatic hemorrhage and Chiari malformations. The present study aim to describe the different types of variations of the falx cerebelli, its morphological features and its association with occipital venous sinuses. Method In this study 49 dura mater was obtained from the Institution of Forensic Medicine. The length, width and the depth of the falx cerebelli were measured using a digital compass. The data obtained were statistically analyzed in relation to age and gender. The relations of the falx cerebelli with the occipital sinus was documented. Histological sections from the falx cerebelli were stained with Hematoxylin Eosin to evaluate the fine structure. Results Among the 49 falx cerebelli examined 36 (73.5%) were classified as normal. The average length, width and depth of the normal falx cerebelli was 3.7, 1.0 and 0.4 cm respectively. Of the 49 falx cerebelli in 1 (2%) case it was absent, in 5 cases (10.2%) duplicate, in 5 cases (10.2%) triplicate, in 1 (2%) case quadruplets and in 1 case (2%) it was five-folded. The proximal and the distal attachments of the falx cerebelli showed 3 types of variations; both attachments triangular, the proximal attachments triangular and the distal ramified and distal attachments triangular and the proximal attachments ramified. The drainage of the occipital sinus of falx cerebelli with variations were evaluated. The increased number of falx cerebelli highly corresponded with the increased number of occipital sinus. Conclusions The dural-venous variation in the posterior cranial fossa can be problematic in various diagnostic and operative procedures of this region. Neurosurgeons should be aware of such variations, as these could be potential sources of haemorrhage during the midline suboccipital and infratentorial approaches.

In Reply to the Letter to the Editor Regarding “Pure Endoscopic Supracerebellar Infratentorial Approach to the Pineal Region: A Case Series”

In Reply to the Letter to the Editor Regarding “Pure Endoscopic Supracerebellar Infratentorial Approach to the Pineal Region: A Case Series”

What is the risk of venous cerebellar infarction in the supracerebellar infratentorial approach?

The supracerebellar infratentorial approach (SCITA) is a standard approach used in a neurosurgical practice. It carries some risk of associated complications including cerebellar venous infarction with possible serious sequelae. The objective of this study is to address the incidence of cerebellar venous infarction in SCITA. A search through the currently available literature was performed in September 2019 from the year 2000 until September 2019 dealing with 'supracerebellar infratentorial approach'. Out of the 578 patients found in thirteen case series, two venous infarctions were present; the remaining four patients were published as case reports. By analysing the case series, we calculated the risk of such a complication to be 0.345% (95% CI [0.061%, 1.248%]). Case reports were not included. The real risk is estimated to be higher. The risk of cerebellar venous infarction is an unpredictable, infrequent but real complication with potentially dreadful sequelae. Each neurosurgeon using this approach should be aware of this event when employing this approach. The avoidance of cerebellar venous infarction can be lowered by leaving as many bridging veins intact as possible.

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

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. 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. 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. 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.