Subtemporal Approach Research Articles

A-080 Prediction Model for Verbal Memory Decline in Different Epilepsy Surgery Procedures: Temporal Lobectomy vs. Amygdalohippocampectomy

Abstract Objective Mathematical models predicting risk of verbal memory decline after resective epilepsy surgery have been developed for patients undergoing temporal lobectomies. This study was undertaken to determine if application of the Stroup memory loss prediction model was as accurate in foreseeing verbal memory decline after temporal lobectomy as in the less invasive selective amygdalohippocampectomy procedure. Method This retrospective study examined the verbal memory performances of 40 left temporal lobectomy (ATL), and 16 left subtemporal approach selective amygdalohippocampectomy (SA-H), patients before and after epilepsy surgery using word list learning (Rey Auditory-Verbal Learning Test, Buschke Selective Reminding Test) and story memory (WMS Logical Memory) tests. Patients were assigned to one of four groups using the Stroup multiple regression equation: Minimal Risk (61% risk). To classify memory decline in individual patients, a pre-to-post surgery decrease of > 1 SD on at least one memory test constituted memory decline. Results The prediction model accurately classified 82% (9/11) of ATL, and 75% (3/4) of SA-H, High Risk patients. Verbal memory loss was higher among ATLs than SA-Hs in the Moderate Risk (87% vs. 18%) and Low Risk (71% vs. 0%) groups. Conclusion The Stroup verbal memory loss risk model under-predicted memory loss among temporal lobectomy patients (71% of Low Risk patients showed memory decline) and over-predicted memory loss among selective amygdalohippocampectomy patients (only 18% of Moderate Risk patients showed memory decline). Results should be considered preliminary due to methodological limitation including small Ns and unequal sample sizes.

Elective inferior temporal lobe resection as an adjunct to subtemporal approach for a case of tentorial meningioma arising from the middle part of the free edge of the tentorium: A case report.

Background: Tentorial meningiomas attached to the inner edge of the tentorium are difficult to excise due to their deep location. Sufficient space may not be always available through a subtemporal approach. Thus, the aim of not retracting the brain is not fulfilled.Methods: To gain surgical corridor, we electively resected the inferior temporal lobe. This helped in greater working space, better visualization, and less chances of venous damage.Results: Employing this technique of elective temporal lobe resection helped us in complete tumor removal without compromising on vision or surgical corridor.Conclusion: A limited inferior temporal lobectomy greatly enhances the working space and vision in cases of difficult tentorial meningiomas. This translates into ease of tumor excision without compromising the patient safety.

Seizure and neuropsychological outcomes in a large series of selective amygdalohippocampectomies with a minimally invasive subtemporal approach.

Debate continues over proper surgical treatment for mesial temporal lobe epilepsy (MTLE). Few large comprehensive studies exist that have examined outcomes for the subtemporal selective amygdalohippocampectomy (sSAH) approach. This study describes a minimally invasive technique for sSAH and examines seizure and neuropsychological outcomes in a large series of patients who underwent sSAH for MTLE. Data for 152 patients (94 women, 61.8%; 58 men, 38.2%) who underwent sSAH performed by a single surgeon were retrospectively reviewed. The sSAH technique involves a small, minimally invasive opening and preserves the anterolateral temporal lobe and the temporal stem. All patients in the study had at least 1 year of follow-up (mean [SD] 4.52 [2.57] years), of whom 57.9% (88/152) had Engel class I seizure outcomes. Of the patients with at least 2 years of follow-up (mean [SD] 5.2 [2.36] years), 56.5% (70/124) had Engel class I seizure outcomes. Preoperative and postoperative neuropsychological test results indicated no significant change in intelligence, verbal comprehension, perceptual reasoning, attention and processing, cognitive flexibility, visuospatial memory, or mood. There was a significant change in word retrieval regardless of the side of surgery and a significant change in verbal memory in patients who underwent dominant-side resection (p < 0.05). Complication rates were low, with a 1.3% (2/152) permanent morbidity rate and 0.0% mortality rate. This study reports a large series of patients who have undergone sSAH, with a comprehensive presentation of a minimally invasive technique. The sSAH approach described in this study appears to be a safe, effective, minimally invasive technique for the treatment of MTLE.

Minimally Invasive Approaches to the Lateral Cavernous Sinus and Meckel's Cave: Comparison of Transorbital and Subtemporal Endoscopic Techniques

Transorbital and subtemporal keyhole approaches have recently been proposed to approach lesions in the lateral wall of the cavernous sinus (CS) and Meckel's cave (MC). Our goal was to compare these approaches and suggest indications for each of them. Five cadaver heads (10 sides, 40 procedures) were used. The lateral transorbital approaches were carried out without and with the removal of the lateral orbital rim, herein referred to as the lateral transorbital approach (LTOA) and the lateral orbital wall approach (LOWA). The subtemporal approaches were performed without and with the removal of the zygomatic arch, referred to as the subtemporal approach (STA) and the subtemporozygomatic approach (STZA). Five targets were chosen and 2 triangles were created representing thelateral wall of the CS and MC. Stereotactic measurements were quantified to calculate angles of attack, surgical freedom, and temporal lobe retraction for each approach. LTOA presented the smaller horizontal angles of attack. LOWA increased the angles to the same level of STA and STZA. STA and STZA presented larger vertical angles of attack. The surgical freedom presented gradual increase from LTOA to LOWA, STA, and STZA. STA and STZA needed greater temporal lobe retraction for most targets. LTOA is a good option to biopsy a lesion in the lateral wall of the CS and LOWA increased the surgical corridor to work with microsurgical techniques. STA and STZA could be better options when wide exposure is necessary, but temporal lobe retraction should be taken into consideration.

Subtemporal Transtentorial Approach in Mesencephalic and Perimesencephalic Lesions in Children-A Series of 20 Patients.

Midbrain and surrounding areas are among the most difficult regions to surgically approach in neurosurgery. The subtemporal approach is a well-known neurosurgical approach that is rarely described in children. To assess the feasibility, advantages, and disadvantages of subtemporal approach in children. A total of 20 pediatric patients with intra-axial tumors involving the lateral midbrain or superior cerebellar peduncle or with extra-axial tumors in the middle incisural space/Meckel cave underwent subtemporal transtentorial approaches with the aim to remove (16 cases) or biopsy (4 cases) their lesions. These cases were retrospectively reviewed and the surgical approach described. Total resection was achieved in 11 patients. In the 4 patients who underwent biopsies, a diagnosis was obtained. A total of 5 patients presented non-neoplastic lesions (dermoid tumors or cavernomas). A total of 9 patients harbored low-grade tumors and 6 high-grade tumors. Patients with low-grade tumors and non-neoplastic lesions are all alive with no evidence of disease or stable residue. Four patients affected by high grade tumors died. No patient suffered permanent neurological deficits related to the surgical approach. Three patients presented temporary neurological deficits following the procedure: one case of strabismus, one case of aphasia and hemiparesis, secondary to delayed, transient thrombosis of the Labbé vein, and 1 case of trigeminal neuralgia. The subtemporal approach represents a feasible approach for mesencephalic and perimesencephalic lesions in children. It provides an ample and direct access, with excellent outcomes and acceptable postoperative morbidity.

Using the Arcuate Eminence-Trigeminal Notch Line to Localize the Anterior Wall of the Internal Auditory Canal in a Subtemporal Approach: An Anatomical Study.

Background This article aims to describe the regional anatomy of the anterior end of the arcuate eminence, the lateral end of the trigeminal notch, and the line connecting the two (i.e., the arcuate eminence-trigeminal notch line [ATL]) and to determine whether the ATL could be used as a landmark for localizing the internal auditory canal (IAC). Methods Twenty sides of the middle cranial fossae were examined. The anterior end of the arcuate eminence, the lateral end of the trigeminal notch, the ATL, and other crucial structures were exposed. The relevant distance and angle of related structures in the anterior wall of the petrosal bone were measured. Results The anterior end of the arcuate eminence and the lateral end of the trigeminal notch could be identified in all specimens. The anterior end of the arcuate eminence lay over the geniculate ganglia and the vestibule area, and could be visualized directly or determined from the intersection of the long axes of the greater superficial petrosal nerve and arcuate eminence. On the petrous ridge, the lateral end of the trigeminal notch was also the transitional point of the suprameatal tubercle and trigeminal notch. The ATL corresponded to the projection of the anterior wall of the IAC on the anterior surface of the petrous bone. Conclusion The ATL corresponded to the projection of the anterior wall of the IAC on the anterior petrous surface and could be used as an alternative landmark for localizing the anterior wall of the IAC.

Keyhole clipping of a low-lying basilar apex aneurysm without posterior clinoidectomy utilizing endoscopic indocyanine green video angiography

Background:Basilar apex (BX) aneurysms are surgically challenging due to their anatomic location, need to traverse neurovascular structures, and proximity to multiple perforator arteries. Surgical approaches often require extensive bone resection and neurovascular manipulation. Visualization of low-lying BX aneurysms is typically obscured by the posterior clinoid and upper clivus and poses a unique challenge. Subtemporal or anterolateral approaches with a posterior clinoidectomy are often required to achieve adequate exposure, though these maneuvers can add invasiveness, risk, and morbidity to the procedure. Endoscopes and, more recently, fluoroscopic angiography capable endoscopes offer the possibility of providing improved visualization with less exposure allowing for minimally invasive clipping.Case Description:We present the case of a 42-year-old female with incidentally found 5 mm middle cerebral artery and 5 mm BX aneurysms. She underwent a minimally invasive supraorbital keyhole craniotomy for the clipping of both aneurysms. While the posterior clinoid obstructed the necessary visualization for the BX aneurysm, use of endoscopy and endoscopic fluoroscopic angiography allowed for safe and successful clipping without the need for a posterior clinoidectomy.Conclusion:This represents the first reported case of a BX aneurysm clipping through a minimally invasive keyhole craniotomy using endoscopic indocyanine green video angiography. Use of endoscopic indocyanine green angiography, combined with keyhole endoscopic approaches, allows for safe minimally invasive clipping of challenging posterior circulation aneurysms.

A history of the Jannetta procedure.

Peter Jannetta was a neurosurgery resident when he proposed the neurovascular compression theory. He built upon the astute observations of Dandy, Gardner, and others who, in the era before the operating microscope, had successfully ventured into the posterior fossa. In 1965, Jannetta performed cranial nerve microdissections for dental students and identified the trigeminal portio intermedia. He proposed that preservation of these sensory fibers may avoid complete facial numbness, and together with Robert Rand developed a subtemporal transtentorial approach for selective rhizotomy for trigeminal neuralgia (TN). Such rash surgery, using an operating microscope, was then forbidden at their University of California, Los Angeles center, so they collaborated with John Alksne to perform the first surgery at Harbor General Hospital. Upon visualizing the trigeminal nerve root, Jannetta was surprised to see a pulsating superior cerebellar artery compressing the nerve and said "That's the cause of the tic." He also hypothesized that alleviating the observed vascular cross-compression may be curative.A few months later, while assessing a patient with hemifacial spasm, Jannetta had the epiphany that this was the same disease process as TN, but instead affecting the facial nerve. The patient consented to what would become Jannetta's first microvascular decompression procedure. The senior faculty members who had forbidden such surgery were away, so the supervising neurosurgeon, Paul Crandall, granted the approval to perform the surgery and assisted. Via a retromastoid approach with the patient in the sitting position and using the operating microscope, Jannetta identified and alleviated the culprit neurovascular compression, with a cure resulting.Jannetta presented his neurovascular compression theory and operative findings to the neurosurgical patriarchy of the time. Elders of the field were generally not inclined to accept the bold speculations of an untested neurosurgeon, and were often determined to discredit the new "cure" of the old diseases. Over decades of refining his surgical technique, documenting the outcomes, and enduring the skepticism he often faced, Jannetta's theory and his microvascular decompression procedure withstood critical analysis and have become recognized as one the great discoveries and advances in neurosurgery and medicine.

A Giant Trigeminal Schwannoma, Posterior Fossa and Middle Fossa Extradural Approach: A Case Report

Trigeminal schwannomas are rare tumors that are located in the posterior and middlecranial fossae in about a quarter of the cases. The presentation pattern is differentaccording to the involved compartment and the goal of surgery is complete removal.We present the case of a 28-years old man who presented with a left sided trigeminalschwannomas extending from the posterior to the middle fossa. Middle fossa part ofthe tumour was removed by extradural subtemporal approach and posterior fossapart was removed by retrosigmoidretromastoid approach Bang. J Neurosurgery 2020; 9(2): 162-167

Comparative anatomical study on the role of zygomatic osteotomy in the extradural subtemporal approach to the clival region, when less is more

A great concern in performing the extradural subtemporal approach (ESTA) is the evaluation of the actual advantage provided by zygomatic osteotomy (ZO). Complications related to zygomatic dissection have been widely reported in the literature, making it of paramount importance to balance the actual need to perform it, against the risk of maneuver-related morbidity. Authors comparatively analyze the putative advantage provided by ZO in the ESTA in terms of anatomic exposure and surgical operability. Technical limits and potentials are critically revised and discussed. A comparative microanatomical laboratory investigation was conducted. The operability score (OS) was applied for quantitative analysis of surgical operability. ZO was found to provide a weakly significant improvement in the surgical angle of attack (p value 0.01) (mean increase 3°). Maneuverability arch (MAC) increase related to ZO did not reach statistical significance (p value 0.09) (mean increase 2°). The variations provided by MAC increase on the conizing effect (CE) did not lead to an actual advantage in the real surgical scenario, modifying the vision area (VA) in terms of reduction of central vision area (CA) in favor of an increase of peripheral vision area (PA) only in the most caudal part of the surgical field. Ultimately, ZO did not influence the overall OS, scoring both ESTA-ZO+ and ESTA-ZO- 2 out of 3. In the ESTA, ZO does not provide an actual significant advantage in terms of surgical operability on clival and paraclival areas.

Therapeutic strategy and effect of different approaches for microsurgical treatment of basilar artery bifurcation aneurysms

Objective To investigate the strategy and effect of microsurgical treatment of basilar artery bifurcation aneurysms with different surgical approaches. Methods We retrospectively reviewed the clinical data of 43 patients with basilar artery bifurcation aneurysms who underwent microsurgical clipping at Department of Neurosurgery, the Second Xiangya Hospital, Central South University from April 2011 to April 2018. Of all 43 cases, 32 cases had ruptured basilar aneurysms and 11 cases had unruptured basilar aneurysms. According to the different morphological and anatomical locations of aneurysms, 17 cases underwent infraorbital approach, 26 cases underwent transsyvian approach (including the transorbirozygomatic approach, the 'half-half’ approach which combined the subtemporal approach with pterion approach and the simple pterion approach) to conduct microsurgical clipping. Intraoperative monitoring was performed using the combination of multiple technologies. Clinical and imaging follow-up was conducted over 6 months post surgery. Results Of all 43 cases with basilar artery bifurcation aneurysms, 38 cases were completely clipped, 4 cases were partially clipped, and 1 case was wrapped. There were 2 cases (4.7%) of hemiplegia after operation, 1 case (2.3%) of coma, 14 cases (32.6%) of oculomotor nerve palsy and no death during perioperative period. Thirty-seven patients (86.4%) were followed up for 25.0±10.1 months (range: 6 months to 4 years). Among them, 35 patients underwent radiographic review without aneurysm residual and 1 patient with partial clipping was treated with second-stage interventional embolization. In 1 case with wrapped aneurysm, the significantly enlargement of aneurysm was not observed in the follow-up image. Of 14 cases with oculomotor nerve palsy after operations, 11 were followed up and 8 of them improved significantly afterwards. Glasgow′s outcome scale(GOS) showed that grade V was reported in 34, grade IV in 1 case, grade III in 1 case, grade II in 0 and grade I in 1 case who died from severe pulmonary infection at 42 days post operation. Conclusions The superior treatment of the basilar artery bifurcation aneurysm could be achieved through subtemporal and transsyvian approach. Preoperative evaluation of anatomical and morphological characteristics of aneurysm seems important for the choice of surgical approach. The application of various assistive techniques during surgery is an important part of ensuring the safety of surgery. Key words: Intracranial aneurysm; Basilar artery; Microsurgery; Treatment outcome

Superficial temporal artery-superior cerebellar artery bypass and direct clipping of a large unruptured superior cerebellar artery aneurysm through subtemporal approach: Surgical video

Background:Superior cerebellar artery (SCA) aneurysms are rare. Current treatments include: direct clipping, trapping ± bypass, and endovascular methods (coiling, stenting, or flow diversion). Due to specific characteristics (wide base, location, and shape), a major challenge while dealing with SCA aneurysms is to preserve the flow of the parent artery and perforators. This video demonstrates a revascularization procedure, and clip reconstruction of a large unruptured basilar artery (BA)/SCA aneurysm performed through the subtemporal approach.Case Description:A 60-year-old woman presented with dizziness and headaches. Computed tomography angiography (CTA) and digital subtraction angiography showed a right unruptured large BA/SCA aneurysm. After multidisciplinary discussion, and considering gender, age, risk factors of the patient. Endovascular treatment was considered with a high risk of ischemic complications. Therefore, the patient was consented for a superficial temporal artery (STA)-SCA bypass through subtemporal approach followed by direct clipping/ trapping of the aneurysm. Postoperative CTA showed occlusion of the aneurysm and patency of the parent vessels. Postoperatively, the patient experienced immediate transient left mild monoparesis and right IV nerve palsy, which recovered completely at 6-months follow-up.Results:Surgical treatment of SCA aneurysms is decreasing due to the existence of endovascular therapies such as stents and flow diverters. However, some cases may necessitate surgical treatment and revascularization procedures to maintain the blood flow of the parent artery and to treat the previous lesion.Conclusion:The STA-SCA bypass through the subtemporal approach is a feasible option to maintain the blood flow of the parent artery in cases of SCA requiring surgical treatment and trapping/direct clipping of the aneurysm.

Planning of Endocranial Supratentorial Basal Cistern and Skull Base Approaches Depending on Venous Patterns Using a Topogram

Because damage or sacrifice of venous drainage during supratentorial basal cistern and skull base approaches may have severe and harmful consequences, methods to identify preoperatively veins at risk are of paramount importance. Among methods, a codified assessment with a venous topogram is helpful, with practical implications. This technical note describes how to construct an easy-to-use topogram. Three regions of interest are defined as triangles. The anterior triangle corresponds to the anterior frontal veins draining to the superior sagittal sinus at risk during anterior cerebral fossa surgery, the middle triangle corresponds to the anterior sylvian veins draining to the cavernous sinus at risk during pterional approaches, and the inferior triangle corresponds to the inferior cerebral veins draining to the transverse sinus at risk in subtemporal approaches and temporal lobe surgery. Depending on predominance of the drainage, 4 situations were defined: an anterior, an inferior, and a middle predominance or equilibrium between the 3 triangles. These anatomic features have important practical implications in skull base and basal cistern approaches. This is, to our knowledge, the only topogram described in the scientific literature. Any well-defined approach should be adapted to the individual patient according not only to location and type of lesion but also to the venous drainage to be encountered along the way.

Preoperative Gabapentin Administration Improves Acute Postoperative Analgesia in Patients Undergoing Craniotomy: A Randomized Controlled Trial.

Gabapentin is an adjuvant antiepileptic agent and helps to reduce acute postoperative pain in several surgery settings. However, the effect of gabapentin on postoperative pain from suboccipital or subtemporal craniotomy is not clear. The study was a single-center, randomized, placebo-controlled, and double-blinded trial. A total of 122 patients undergoing elective craniotomy by a suboccipital or subtemporal approach were randomly allocated to a placebo group and gabapentin group. The patients received gabapentin (600 mg, orally) the night before surgery and 2 hours before anesthesia induction in the gabapentin group, and patients received vitamin B in the placebo group. The primary outcome was the postoperative pain score on movement at 24 hours. The secondary outcomes included the pain score at other time points, incidence of nausea and vomiting, sedation, and analgesic consumption. Gabapentin significantly decreased the postoperative acute pain scores at rest (P=0.001) and on movement (P=0.000) within 24 hours; however, it did not have an effect at 48 hours. Gabapentin decreased postoperative vomiting (P=0.047) and rescue antiemetic use (P=0.033), whereas it increased the postoperative sedation score at 2 hours (P<0.05). Moreover, gabapentin decreased the mean consumption of intraoperative propofol (0.7 mg/kg/h; P=0.021) and remifentanil (1.3 µg/kg/h; P=0.025); however, it did not influence postoperative opioid consumption. Preoperative gabapentin significantly alleviated acute postoperative pain and decreased the incidence of vomiting in patients undergoing suboccipital or subtemporal craniotomy. However, more attention should be paid to early postoperative sedation when multimodal analgesia with gabapentin is administered.

Subtemporal transtentorial approach for resection of a pontomesencephalic cavernous malformation.

In this 3D video we review the case of a pontomesencephalic cavernous malformation in a 27-year-old woman who presented with hemiparesis and diplopia. The cavernous malformation was completely resected through a subtemporal transtentorial approach and an epitrigeminal brainstem entry zone, with a significant improvement in the patient’s hemiparesis. The relevant anatomy is reviewed in detail through multiple anatomical brainstem dissection specimens, as well as high-definition fiber tractography images. The rationale for the approach is analyzed relative to other possible options, and a number of technical pearls are provided.The video can be found here: https://youtu.be/8EoIWL7XqAc.

Two cases of brainstem neurocysticercosis removal: operative video.

Neurocysticercosis is primarily managed with anthelminthic, antiepileptic, and corticosteroid therapies. Surgical removal of the larval cyst is indicated when associated mass effect causes neurological symptoms, as demonstrated in two cases. Cyst resection was achieved via the far lateral approach for a cervicomedullary cyst in one patient and via the subtemporal approach for a mesencephalic cyst in another. The cyst wall should be kept intact, when possible, to avoid dissemination of the inflammation-evoking contents. As the contents are usually semisolid and can be removed via suction, it is not necessary to remove the gliotic capsule or adherent portions of the cyst wall in highly eloquent locations.The video can be found here: https://youtu.be/GqbaJu5sy1o.

Traumatic dislocation of the mandibular condyle into the middle cranial fossa complicated by temporal lobe intracerebral hemorrhage: literature review and our case

Dislocation of the mandibular condyle into the middle cranial fossa is a rare complication of mandibular trauma due to anatomical and biomechanical factors. Due to the proximity of the mandibular condyle to the middle cranial fossa and middle meningeal artery, there is the risk of serious sequelae in case of trauma. The authors report the case of a 31-year-old female patient, who was beaten up in a family dispute. Computer tomography results demonstrated a basilar skull fracture, pneumocephalus, the dislocation of the mandible into the middle cranial fossa. The patient was hospitalized in the neurosurgical department; anti-edema treatment and antibiotic therapy were prescribed. During the first day, deterioration of the condition presented with rising headache and a gradual suppression of consciousness (GCS 13). The control tomography of the brain revealed negative dynamics in the form of development of intracerebral hemorrhage in the right temporal lobe, subdural hematoma to the right and lateral dislocation of the median structures to the left.The patient was operated in critical situation. Right-sided subtemporal approach and cranial trepanation were performed. There were removed numerous bone fragments of a multi-fragile fracture of the petrous part of the right temporal bone. A reposition of the mandibular condyle was performed by pull-through of the latter from the middle cranial fossa. The intracerebral hemorrhage of the right temporal lobe was removed, and a thorough hemostasis was performed. In addition, skull base reconstruction was performed. Rapid diagnosis and a multidisciplinary approach are needed to minimize complications. The modern opportunities of reconstruction of imaging using the CT method were applied. Treatment options should be individualized in case of suspicion of intracranial hematoma formation.

The infratranstentorial subtemporal approach (ITSTA): a valuable skull base approach to deep-seated non-skull base pathology.

Surgical access to space-occupying lesions such as tumors and vascular malformations located in the area of the tentorial notch, mediobasal temporal lobe, and para-midbrain is difficult. Lesions in this area are typically resected with supratentorial approaches demanding significant elevation of the temporal lobe or even partial lobectomy, or via a supracerebellar transtentorial approach. We introduce an alternative, the skull base infratranstentorial subtemporal approach (ITSTA), which provides excellent exposure of the incisural area while minimizing risk to the temporal lobe. We included consecutive patients with pathology involving the area of the tentorial incisura, para-midbrain, and mediobasal temporal area who underwent surgery via ITSTA from 2012 to 2018. The approach includes partial mastoidectomy, temporal craniotomy, and tentorial section. Space obtained by mastoidectomy provides a sharp high-rising angle-of-attack, significantly diminishing the need for temporal lobe retraction. Surgeries were performed using microsurgical techniques, neuronavigation, and electrophysiological monitoring. Clinical presentation, tumor characteristics, extent of resection, complications, and outcome were retrospectively reviewed under a waiver of informed consent. Nine patients met inclusion criteria (five female, four male; mean age 44years, range 7-72). They underwent surgery for removal of para-midbrain arteriovenous malformation (AVM, 3/9), medial tentorial meningioma (2/9), mediobasal epidermoid cyst (2/9), oculomotor schwannoma (1/9), or pleomorphic xanthoastrocytoma (PXA) of the fusiform gyrus (1/9). Three AVMs were removed completely; among six patients with tumors, gross total resection was achieved in three and subtotal resection in three. All surgeries were uneventful without complications. There were no new permanent neurological deficits. At late follow-up (mean 42.5months), eight patients had a Glasgow Outcome Score (GOS) of 5. One 66-year-old female died 18months after surgery for reasons not related to her disease or surgery. The ITSTA is a valuable skull base approach for removal of non-skull base pathologies located in the difficult tentorial-incisural parabrainstem area.

Minimally Invasive Endoscopic Keyhole Approach for Meningiomas

Abstract INTRODUCTION The advantages of neuroendoscopic surgery are wide viewing angle and freedom of axis of view with minimal surgical trauma. Taking advantage of the features of neuroendoscopy, the authors report the experience of minimally invasive endoscopic keyhole approach (EKA) for various meningiomas. METHODS A total of 28 cases of various type of meningiomas were treated by EKA from 2007 to 2018. A keyhole of about 2.5 cm was created according to the case, and tumor removal was performed using an endoscope and exoscope. The scope was held by a pneumatic holder controlled by the assistant to continue the procedure in a comfortable environment. RESULTS EKAs were performed for anterior skullbase lesions via eyebrow skin incision (n = 12), posterior fossa lesions including tentorial meningiomas, torcular meningiomas (n = 7), falcine lesions (n = 6), subtemporal approach (n = 2), enplaque convexity menigiomas (n = 1). All the tumors were resected as planned with minimum brain retraction and well-illuminated fine vision in deep corner. In the cases of a large tumor in the elderly, maximum internal decompression was performed, and the adhered tumor was left on the surface of the brain to avoid injury. The brain retraction was automatically limited by the small craniotomy, and excellent magnified image in deep corner was obtained by EKA. By eliminating the blind spots, radical resection is achieved. Also, in the aging society, depending on the patient with benign meningioma, it is important to consider what better treatment is, to alleviate symptoms and to coexist with the tumor. The cooperation of the assistant is important for this approach. To avoid the interference between the endoscope and the instrument, it is necessary to have a technique for moving the endoscope as needed in order to keep the fine visual field. CONCLUSION In the treatment of meningioma, the role of endoscopes is important in both the radicality obtained in a wide field of view and the less invasiveness in the aging society.

Temporal myofascial segmentation for multilayer reconstruction of middle cranial fossa floor after extradural subtemporal approach to the clival and paraclival region.

Skull-base reconstruction represents a concern after resection of middle fossa (MF) tumors by the extradural subtemporal transzygomatic approach (ESTZ). Regional pedicled flaps appear to be the best option. This study describes a technique for temporal myofascial segmentation to harvest a multilayered vascularized flap for MF reconstruction, which might preserve temporal muscle (TM) function and its blood supply. The technique to harvest a combined segmented temporal myofascial flap (CSTMF) is described. The flap consists in a temporal fascial (TFF) and a muscle flap (TMF), composed by TM anterior-medial bundle (AMB). CSTMF provides wide coverage of dural lining, through the TFF, and of dead-space, through the TMF. The possibility to tailor TMF according to the need, anatomically preserving the blood supply, enables to significantly increase its volume. CSTMF represents an effective option as regional multilayered pedicled flap for MF reconstruction, potentially preserving TM function and minimizing the cosmetic impact.