Transpetrosal-transtentorial Approach Research Articles

Combined transpetrosal-transtentorial approach with occipital artery – anterior inferior cerebellar artery bypass and aneurysm clipping for a lower basilar artery aneurysm involving anterior inferior cerebellar artery: Two-dimensional operative video

Background: Aneurysms of the lower basilar artery (BA) are rare, accounting for <1% of all intracranial aneurysms. This location has been described as “No man’s land” since it poses a potential challenge for microsurgery. Recently, endovascular treatment has become an alternative option; however, there are some disadvantages regarding the obliteration rate, patency of the parent, and perforating arteries. Case Description: We present the case of a 69-year-old female with an incidentally found lower BA aneurysm. The imaging examinations revealed a wide-neck aneurysm size of 8.5 mm arising just distal to the vertebrobasilar junction, with involvement of the left anterior inferior cerebellar artery (AICA). After a discussion with the patient, she opted to undergo the surgical treatment. We described the detailed steps of our surgical techniques in performing a combined transpetrosal-transtentorial approach. First, the occipital artery (OA) was harvested. Then, the posterior transpetrosal (retrolabyrinthine) and a far-lateral suboccipital approach were conducted with tentorial sectioning to expose the aneurysm. After AICA was confirmed to arise from the aneurysm sac, the OAAICA bypass was established to ensure AICA patency, followed by complete aneurysm clipping. The approach provided both the presigmoid and retrosigmoid corridors for bypass and clipping procedures, respectively. The patient tolerated the procedure well. Postoperative imaging examinations showed complete aneurysm obliteration and bypass patency without complications. She was discharged without neurological deficits (modified Rankin Scale 0). Conclusion: The combined transpetrosal approach is safe and effective for revascularization and clipping procedure for a lower BA aneurysm.

Scratching in the minefield: using intertriangles line to safely perform anterior petrosectomy.

The transpetrosal-transtentorial approach provides a practical and safe surgical corridor for the treatment of petroclival region lesions. Any inaccuracies while performing this surgical technique can result in catastrophic results; nevertheless, this can be prevented under the guidance of a detailed anatomical orientation. An "intertriangles line" was defined to preserve the internal auditory canal (IAC) and cochlea during extradural bone drilling. The anatomical study consisted of two groups: the cadaveric head and the skull group. A literature-based landmark and criteria list was created to examine the borders of the Kawase triangle/space and evaluate the anatomical structures that may be at risk during drilling for anterior petrosectomy. A total of 20 cadaveric head sides and 30 dried skull sides were examined. The rhomboid area was divided into two triangles with a common the intertriangles line. In all dissections, the IAC was found to be localized posterior to the "intertriangle line". A minimum distance of 1mm for the Internal Carotid artery and 2mm for the IAC can serve as threshold values to be considered by the surgeon during drilling for petrosectomy. Kawase's area resembles a minefield, in which every step and manipulation should be considered. A minimal but effective resection of the cranial base is needed to increase safety and decrease morbidity during skull base surgery. Furthermore, this study investigated accessible and prominent landmarks to establish a feasible area of triangles and define the intertriangles line to guide the neurosurgeon under microscope and avoid IAC injury.

Suprasellar Tumor-Craniotomy

Surgical procedures for pediatric suprasellar tumors include craniotomy and nasal surgery. Craniotomies are increasingly performed with a microscope, exoscope, and endoscope, while nasal surgery is performed mainly with endoscopes. In some cases, craniotomy and nasal surgery are performed together. This article describes craniotomy. Due to its large surgical field, craniotomy is often chosen for large tumors in the suprasellar region, tumors located above the optic chiasm and optic nerve, tumors extending laterally, and hypervascularized tumors. It is the surgical technique of choice for many neurosurgeons because they are familiar with it. Craniotomies include bilateral frontal and frontotemporal craniotomies. The interhemispheric and subfrontal approaches involve bilateral frontal craniotomy, pterional approach, orbitozygomatic approach, subtemporal approach using temporal-occipital craniotomy, and transpetrosal transtentorial approach using temporal-occipital-suboccipital craniotomy. The approach was selected based on the direction of tumor extension and relationship between the tumor and optic nerve, optic chiasm, and blood vessels. This paper describes the frequently used interhemispheric and pterional approaches based on our experience.

Modified Transpetrosal-Transtentorial Approach for Resection of Large and Giant Petroclival Meningioma: Technical Nuance and Surgical Experiences.

Meningiomas arising from the petroclival area remain a challenge for neurosurgeons. Various approaches have been proposed to achieve maximum resection with minimal morbidity and mortality. Also, some articles correlated preservation of adjacent veins with less neurologic deficits. To describe the experiences in using a new technique to achieve maximal resection of petroclival meningiomas and preserving the superior petrosal veins (SPVs) and the superior petrosal sinus (SPS). A retrospective analysis of 26 patients harboring a true petroclival meningioma with a diameter ≥25 mm and undergoing surgery with the modified transpetrosal-transtentorial approach (MTTA) was performed. Fifty-four percent of 22 patients complained of severe headache at presentation. There was also complaint of cranial nerve (CN) deficit, with CN VII deficit being the most common (present in 42% of patients). The average tumor size (measured as maximum diameter) was 45.2 mm, and most of the tumors compressed the brainstem. Total resection was achieved in 12 patients (46.2%), whereas the others were excised subtotally (54.8%). Most of the patients had WHO grade I (96.1%) meningioma; only one had a grade II (3.8%) meningioma. In addition, clinical improvement and persistence of symptoms were observed in 17 (65.4%) and 8 (30.7%) patients, respectively, and postoperative permanent CN injury was observed in 3 (11.5%) patients. Using the MTTA, maximal resection with preservation of the CNs and neurovascular SPV-SPS complex can be achieved. Therefore, further studies and improvements of the technique are required to increase the total resection rate without neglecting the complications that may develop postoperatively.

Endoscopic transcanal transpetrosal approach to the petroclival region: a cadaveric study with comparison to the Kawase approach.

This study introduces expanded application of the endoscopic transcanal approach with anterior petrosectomy (ETAP) in reaching the petroclival region, which was compared through a quantitative analysis to the middle fossa transpetrosal-transtentorial approach (Kawase approach). Anatomical dissections were performed in five cadaveric heads. For each head, the ETAP was performed on one side with a detailed description of each step, while the Kawase approach was performed on the contralateral side. Quantitative measurements of the exposed area over the ventrolateral surface of the brainstem, and of the angles of attack to the posterior margin of the trigeminal nerve root entry zone (CN V-REZ) and porus acusticus internus (PAI) were obtained for statistical comparison. The ETAP provided significantly larger exposure over the ventrolateral surface of the pons (93.03 ± 21.87mm2) than did the Kawase approach (34.57 ± 11.78mm2). In contrast to the ETAP, the Kawase approach afforded greater angles of attack to the CN V-REZ and PAI in the vertical and horizontal planes. The ETAP is a feasible and minimally invasive procedure for accessing the petroclival region. In comparison to the Kawase approach, the ETAP allows for fully anterior petrosectomy and larger exposure over the ventrolateral surface of the brainstem without passing through the cranial nerves or requiring traction of the temporal lobe.

Anterior Transpetrosal Approach for Trigeminal Schwannoma with Persistent Primitive Trigeminal Artery: 2-Dimensional Operative Video.

The surgical management of trigeminal schwannomas often requires complicated skull base approaches based on detailed anatomical understanding because of the involvement of multiple compartments of the trigeminal nerve from its root to the peripheral branches. When there is vital anatomical anomaly around the tumor, this can make the surgical management and anatomical understanding more difficult.1,2 This video demonstrates the microsurgical removal of a dumbbell-shaped trigeminal schwannoma via the anterior transpetrosal transtentorial approach in a patient with a persistent primitive trigeminal artery, the most common persistent embryonic carotid-vertebrobasilar anastomosis. A 32-yr-old woman presented with progressive facial sensory impairment, dizziness, and slight diplopia because of right abducens palsy. Neuroimaging revealed a right Meckel's cave tumor extending to both the middle and posterior cranial fossae and displacing the abducens nerve inferomedially. The persistent primitive trigeminal artery, which is an anomalous communication between the cavernous carotid and basilar arteries, was identified ventral to the tumor. While preserving most of the noninvaded trigeminal nerve, gross-total resection was achieved under direct visualization of the abducens nerve and persistent primitive trigeminal artery, piercing the dura of the posterior cavernous sinus and coursing medially along the clivus. The patient's facial sensory impairment and diplopia almost disappeared without new neurological deficits or tumor recurrence during the follow-up period of 1 yr. Three-dimensional reconstructed images demonstrated the anatomical relationship of the tumor, the persistent primitive trigeminal artery, and the extent of osseous drilling of the petrosectomy. Informed consent was obtained from the patient.

The Tentorial Bridge to Deep Skull Base Exposure: Anatomic Morphometric Study.

Skull base surgeons split the tentorium to expand exposure, minimize brain retraction, and combine the supratentorial and infratentorial compartments for resection of large skull base lesions. The aim of this study was to describe stepwise techniques for splitting the tentorium to access deeply located skull base lesions and morphometrically assess gained exposure. Surgical exposures were performed through transsylvian, subtemporal, posterior transpetrosal, and combined posterior supratentorial/infratentorial-transsinus approaches. A custom software program was used to trace the surgical exposure region of interest for area analysis with the ability to accurately assess most irregular areas. Qualitative morphometric assessment was done of the gain in anatomic exposure achieved by splitting the tentorium. In the transsylvian transtentorial approach, mean surface area increased 154.17%, from 0.14 cm2 before expansion to 0.32 cm2 after expansion. In the subtemporal transtentorial approach, mean surface area increased 137.61%, from 0.66 cm2 before expansion to 1.52 cm2 after expansion. In the posterior transpetrosal transtentorial approach, mean surface area increased 171.06%, from 1.08cm2 before expansion to 2.81 cm2 after expansion. Inthe combined supratentorial/infratentorial-transsinus approach, mean surface area increased 222.03%, from 0.78cm2 before expansion to 2.38 cm2 after expansion. With splitting of the tentorium, a substantial area of expansion is obtained, minimizing the need for brain retraction and improving visualization of deep neurovascular structures in the skull base.

Microsurgical resection of petroclival meningiomas by subtemporal transpetrosal-transtentorial approach assisted with neuroendoscopy

Objective To study the removal technique and operative experiences in the microsurgical resection of petroclival meningiomas with the subtemporal transpetrosal-transtentorial approach assisted with neuroendoscopy,and to improve the rate of total resection of tumors and the postoperative results.Methods Consecutive 21 cases of petroclival meningiomas treated from Jan.2002 to Jun.2012 by microsurgical technique using the subtemporal transpetrosal-transtentorial approach were reviewed retrospectively.Among the 21 cases,11 patients were operated with an assistance of neuroendoscopy.The tumor control rate,postoperative neurological deficit,and functional status were assessed by the Karnofsky Performance Score (KPS),and to evaluate the indications,advantages and disadvantages of this approach in assistance with neuroendoscopy.Results Gross total tumor resection was achieved in 10 patients,subtotal resection in 8 cases,and partial resection in 3 cases.New developed cranial nerves dysfunction and deterioration of original symptom after the operation were found in 7 patients.There were no deaths and longterm coma.The surgical results of patients assisted with neuroendoscopy were better than only using microscope,P ＜ 0.05.Conclusions The subtemporal transpetrosal-transtentorial approach in assistance with neuroendoscopy is suitable for petroclival meningiomas mainly in the middle fossa with extension to the posterior fossa (type Ⅰ).By resecting the petroal bone,this approach can improve the rate of total resection of tumors and the postoperative results,while decreasing the postoperative functional deficit of the cranial nerves. Key words: Petroclival meningioma ; Neuroendoscopy; Microsurgery ; Subtemporal transpetrosal-transtentorial approach

Microsurgical anatomy and locating of the vein of Labbé by 3D-CTV in temproal base transpetrosal transtentorial approach

Objective The anatomical shape and location of the vein of Labbe were investigated and 3D-CT venography （3D-CTV） was used to identify and locate the vein of Labbe preoperation to protect the vein for temporal base transpetrosal transtentorial approach. Methods Ten cadaver heads for a total of 20 sides were examined. 8 patients with petroclival tumor received 3D-CTV examination to investigate and locating of the vein of Labbe before operation. The outcome of the 3D-CTV examination for the vein of Labbe was checked by the operation. Results The vein of Labbe can be divided into three different patterns. The distance between the terminations of the vein of Labbe and STP was （22.91±8.09） mm, with less than 10 mm in 10%. The shape of the vein of Labbe displayed by 3D-CTV was clear and same as the shape displayed in operation, and the distance between the terminations of the vein of Labbe and STP measured by 3D-CTV was also same with the value measured in the operation. Conclusions Comparing with MRV and DSA, 3D-CTV examination can locate the vein of Labbe more easily and exactly, and it should be performed and scrutinized carefully before planning the temporal base transpetrosal transtentorial approach. Key words: Vein of Labbe ; 3D-CTV ; Micrusurgical anatomy ; Temporal base transpetrosal transtentorial approach

Applied anatomical study of the temporal base transtentorial transpetrosal approach

Objective To explore the resecting region of the petrosal bone and the extended exposed area in temporal base transpetrosal transtentorial approach(TBTTA).Method Ten adult cadaver heads for a total of 20 sides were performed by TBTTA and the resecting region of the petrosal bone was identified in this approach.The exposure at petroclivus and the angle of temporal base retraction was evaluated in TBTTA approach.Results The petrosal bone can be divided into three parties by the internal acoustic canal.In the medial part,the drilling area was 6.6 mm wide and 5 mm long above the internal acoustic foramen(2 mm long above the bottom of internal acoustic canal).In the intermediate part,the safe drilling area was 15 mm long and 9 mm wide.In the lateral part,the resecting area between the internal auditory canal and semicircular canals was 8.7 mm long and 5 mm wide:and in the area of semicircular canals,the drilling deep should be restricted within 3.7 mm.After resecting the petrosal bone which block the visual of the most part of the pefrosal posterior wall,the exposed area was obviously enlarged,and the temporal base retracting angle reduced.Conclusions TBTTA approach can significantly improve the visual field in the petroclival region and reduce the degree of the temporal base retraction by resecting petrosal ridge. Key words: Temporal base transtentorial transpetrosal approach(TBTTA); Petroclival region; Surgical procedures,operative

Surgery combined with radiosurgery of large acoustic neuromas

Background The treatment of acoustic neuromas has been improved by advancements in microsurgical techniques and in radiosurgery. To further elucidate the degree of clinical improvement, we evaluated the treatment results of a combination of surgery and radiosurgery for large acoustic neuromas. Methods From January 1994 through December 2000, we treated 14 patients with large acoustic neuromas using a combination of surgery and radiosurgery. Of these, 8 were male and 6 were female patients, with an average age of 47 years (range, 18–64). The average maximum diameter of the tumor was 42 mm (range, 30–58 mm). All patients underwent operations using the retrosigmoid approach, and one patient was retreated using the transpetrosal transtentorial approach. The tumors were removed subtotally in thirteen patients and partially in one who had a very large hypervascular acoustic neuroma. There were no mortality and no surgical complications, such as hemorrhage or CSF leakage. Postoperative facial palsy was avoided in 10 patients (71%). Radiosurgery was performed 1 to 6 months (mean, 2.9 months) after surgery. At the time of radiosurgery, the treatment size (mean diameter) became 19.2 mm (range, 9.8–36.1 mm). The average tumor marginal dose was 12.1Gy (range, from 10–14 Gy). The mean follow-up period was 32 months after radiosurgery. Results The tumor size decreased in 6 patients, unchanged in 5 patients, and increased in 3 patients. Only 1 patient (7%) with extra large tumor needed surgical resection 1 year after radiosurgery. Excellent facial nerve function (House & Brackmann Grade I or II) was preserved in 12 patients (85.7%) in the final follow-up. Conclusions In the case of large acoustic neuromas, subtotal removal and subsequent radiosurgery is one option for maintaining cranial nerve function and long-term tumor growth control.

Abnormal Course of the Oculomotor Nerve on the Clivus Combined with a Petroclival Meningioma: Case Report

The course of the oculomotor nerve on the clivus was abnormal in a patient with petroclival meningioma. He complained of gait disturbance. A gadolinium-enhanced magnetic resonance image demonstrated a 4.4-cm enhancing mass in the petroclival region. The tumor was removed via an anterior transpetrosal-transtentorial approach. Normally, the oculomotor nerve originates from the brainstem and enters the oculomotor trigone. In this patient, the oculomotor nerve entered the dura mater at the upper clivus, behind the posterior clinoid process, and coursed parallel to the basilar artery. This entrance is lower than the normal entry point of the oculomotor nerve. The abnormal entrance of the oculomotor nerve may reflect an atypical developmental relationship among the cranial nerves, meninges, and bones during embryogenesis.

Use of a Split Bone Graft To Correct the Cosmetic Deformity Associated with the Transpetrosal-Transtentorial Surgical Approach: Technical Report

OBJECTIVE: Split bone graft reconstruction was performed after a standard transpetrosal-transtentorial approach to correct the cosmetic deformity in 18 patients. TECHNIQUE: The split bone graft was made by dividing the inner table of the temporosuboccipital bone graft and covered the bone defect created by petrosectomy and mastoidectomy. The split bone graft was created and shaped during closure of the dura, so that the operation was not prolonged. RESULTS: This technique produced excellent cosmetic results immediately after surgery; the results were maintained during the follow-up period of between 20 and 46 months. No complication associated with this technique was recognized. CONCLUSION: Split bone graft reconstruction is a simple and safe technique for preventing the cosmetic deformity associated with a transpetrosal-transtentorial approach.

Use of a split bone graft to correct the cosmetic deformity associated with the transpetrosal-transtentorial surgical approach: technical report.

Split bone graft reconstruction was performed after a standard transpetrosal-transtentorial approach to correct the cosmetic deformity in 18 patients. The split bone graft was made by dividing the inner table of the temporosuboccipital bone graft and covered the bone effect created by petrosectomy and mastoidectomy. The split bone graft was created and shaped during closure of the dura, so that the operation was not prolonged. This technique produced excellent cosmetic results immediately after surgery; the results were maintained during the follow-up period of between 20 and 46 months. No complication associated with this technique was recognized. Split bone graft reconstruction is a simple and safe technique for preventing the cosmetic deformity associated with a transpetrosal-transtentorial approach.

En bloc petrosectomy using a Gigli saw for petroclival lesions. Technical note.

The authors report a new technique for en bloc petrosectomy using a Gigli saw as an alternative to drilling the petrous bone in the combined supra- and infratentorial approach or the transpetrosal-transtentorial approach. It is simple and easy and avoids postoperative cosmetic deformity. This technique has been performed in 11 petroclival lesions without injuring the semicircular canals, the cochlea, or the facial nerve.

頭蓋底部病変へのアプローチにおける Labbé 静脈温存法

Preservation of large draining veins bridging the cortex and sinuses is extremely important for prevention of postoperative intracerebral hemorrhage. The vein of Labbé is also important and has been preserved during subtemporal approach using the arachnoid dissecting technique, partial cortex removing technique and intermittent retraction technique. But these techniques have absolute limitations because the subtemporal approach passes through a space between the tentorium and the temporal cortex.We have performed the presigmoidal transpetrosal transtentorial approach preserving the vein of Labbé by the following technique. After completion of lateral suboccipital craniectomy and temporal craniotomy, the sigmoid sinus has been completely exposed to the jugular bulb epidurally. The superior petrosal sinus has been ligated and cut between two ligatures. The tentorium has been completely cut.In some instances, there are small bridging veins draining into the tentorium. In these cases, tentoriotomy is performed in front of the entrance of these veins. After cutting the tentorium, the sigmoid sinus has been mobilized posteriorly and the tentorium, the transverse sinus, the vein of Labbé and the temporal lobe superiorly. In this technique, the vein of Labbé and the temporal cortex can be mobilized together in the same direction and there is no traction force between them. This technique is quite important and useful for preservation of the vein of Labbéduring skull base surgery.

A combined retroauricular and preauricular transpetrosal-transtentorial approach to clivus meningiomas

A combined retroauricular and preauricular transpetrosal-transtentorial approach is described for the resection of meningiomas arising from the clivus. Via radical mastoidectomy the sigmoid sinus is exposed down to the jugular bulb, and via the transmastoideal-subtemporal approach the retroauricular petrosal bone, 1 cm in depth from the petrosal ridge, and the roof of the internal auditory meatus are removed, the middle ear and fallopian canal being left intact. Additionally, via a transzygomatic-subtemporal approach the preauricular petrosal bone is removed anteriorly up to the petrosal tip and laterally as far as the petrosal portion of the internal carotid artery, while the cochlea is preserved. By this means, the triangular portion of the posterior petrosal dura mater, delimited by the superior petrosal sinus, inferior petrosal sinus, and sigmoid sinus, is well exposed extradurally. By opening the subtemporal and posterior petrosal dura mater, in combination with a tentoriotomy, adequate exposure of the basilar artery, vertebral arteries, ventral and lateral portions of the brainstem, and cranial nerves is achieved with minimal retraction of the temporal lobe and cerebellum.

Transpetrosal-transtentorial approach and its application in the therapy of retrochiasmatic craniopharyngiomas

Our experience with the transpetrosal-transtentorial approach to retrochiasmatic craniopharyngiomas is herein reviewed and an operative technique is described. Excellent exposure of the retrochiasmatic and suprasellar regions is gained with a minimal retraction of the temporal lobe and cerebellum. Eight cases of retrochiasmatic craniopharyngiomas that extended into the posterior hypothalamus were operated on utilizing this approach. The operative results were excellent in five patients, good in one, and poor in one. There was one death later. The principal advantage of this technique is that it allows the hypothalamus, even in cases in which the structure is remarkably displaced upwards, the third ventricular walls in cases of the intraventricular extension of the tumor, and the inferior surface of the optic chiasma and nerves to be visualized directly and thus safely preserved.