Transpetrosal Approach Research Articles

A suggestion of modified classification of trigeminal schwannomas according to location, shape, and extension.

BackgroundComprehensive knowledge of the anatomical features of trigeminal schwannomas (TSs) is essential in planning surgery to achieve complete tumor resection. In the current report, we propose a modified classification of TSs according to their location of origin, shape, and extension into the adjacent compartment, and discuss appropriate surgical strategies with this classification.MethodsWe retrospectively analyzed 49 patients with TS who were treated surgically by a single neurosurgeon at the Asan Medical Center between 1993 and 2013.ResultsThere were 22 males and 27 females, with the median age of 40 years (range, 21-75 years). Median tumor size was 4.0 cm in diameter (2.0-7.0 cm). Tumors were classified as follows: Type M (confined to the middle fossa; 8 cases, 19.0%), P (confined to the posterior fossa; 2 cases, 4.8%), MP (involving equally both middle and posterior fossae; 5 cases, 11.9%), Mp (predominantly middle fossa with posterior fossa extension; 6 cases, 14.3%), Pm (predominantly posterior fossa with middle fossa extension; 16 cases, 38.1%), Me (predominantly middle fossa with extracranial extension; 4 cases, 9.5%). Surgical approach was chosen depending on the tumor classification. More specifically, a frontotemporal craniotomy and extradural approach with or without zygomatic or orbitozygomatic osteotomy was applied to M- or Mp-type tumors; a lateral suboccipital craniotomy with or without suprameatal approach was applied to the majority of P- or Pm-type tumors; and a posterior transpetrosal approach was used in four tumors (three Pm and one MP). Gross total resection was achieved in 95.9% of patients, and the overall recurrence rate was 4.1% (2 patients). Postoperatively, trigeminal symptoms were improved or unchanged in 51.0% of cases (25 patients). Surgical complications included meningitis (5 patients) and cerebrospinal fluid leakage (3 patients). There was no mortality.ConclusionTSs are well to be classified with our modified classification and able to be removed effectively and safely by selecting appropriate surgical approaches.

The Middle Fossa Approach for the Removal of a Trochlear Schwannoma

Objectives. Schwannomas originating from the trochlear nerve are extremely rare; only 30 cases have been reported in the literature. Many operative approaches have been utilized for lesion resection, but the advantages of the anterior transpetrosal approach are numerous and include excellent exposure, minimal extradural retraction of the temporal lobe, and minimal cerebrospinal fluid leaks. We report the second case of a trochlear schwannoma resected via the anterior transpetrosal approach. Setting. A 64-year-old male presented with 3-month history of diplopia and headaches. On physical examination, he was found to have a right fourth nerve palsy. Brain magnetic resonance imaging revealed a mass within the right ambient cistern compressing the adjacent midbrain. A right-sided anterior transpetrosal approach was used—which confirmed that the trochlear nerve entered the mass—to achieve gross total resection. Pathological examination confirmed diagnosis of schwannoma. The patient was discharged on postoperative day 3. He experienced a persistent fourth nerve palsy postoperatively with an otherwise normal neurological examination. Follow-up imaging confirmed complete removal of the tumor. Conclusion. The anterior transpetrosal approach is an excellent approach for removal of trochlear schwannomas involving the cisternal course of the trochlear nerve. It affords complete visualization of this anatomical region while introducing minimal morbidity.

橋海綿状血管腫に対する経錐体到達法

橋海綿状血管腫に対する経錐体到達法

Petroclival meningiomas: an update on surgical approaches, decision making, and treatment results

Petroclival meningiomas remain a formidable challenge for neurosurgeons because of their location deep within the skull base and proximity to eloquent neurovascular structures. Various skull base approaches have been used in their treatment, and deciding which is the optimal one remains controversial. Attempts at achieving gross- or near-total resections are associated with an increased rate of morbidity and mortality. As adjunctive treatment options such as stereotactic radiosurgery have been developed and become widely available, there has been a trend toward accepting subtotal resections in an effort to minimize neurological morbidity. This paper reviews a recent series of patients with petroclival meningiomas and highlights current management trends and important considerations useful in surgical decision making. The records of patients with large (> 3 cm) petroclival meningiomas surgically treated by the senior author over the past 5 years were reviewed. The clinical results are presented as examples of the surgical approaches available for approaching these tumors, and treatment options are reviewed. Of 196 meningiomas surgically treated during the study period, 8 lesions in 8 patients met the study criteria. Overall clinical results were excellent, with no death or major morbidity. Intracranial gross- or near-total resection (Simpson Grade 1, 2, or 3) was achieved in 5 patients (67%). New cranial nerve deficits occurred in 3 patients (37%) and were more common in patients in whom a subtotal resection was performed (2 of 3 cases). A variety of surgical approaches were used. Important considerations determining the best approach include the location of the tumor relative to the internal auditory canal, the presence of preoperative hearing loss, and the location of the tumor relative to the tentorium. Achieving gross- or near-total resections of large petroclival meningiomas remains achievable and should be the primary goal of surgical treatment. A retrosigmoid craniotomy remains a workhorse surgical approach for most petroclival tumors of any size. Tumors that are medial to the internal auditory canal and span both middle and posterior cranial fossae are often best treated with a combined transpetrosal approach, which is especially true if there is a preoperative hearing deficit.

Surgical outcomes of the minimum anterior and posterior combined transpetrosal approach for resection of retrochiasmatic craniopharyngiomas with complicated conditions

Retrochiasmatic craniopharyngiomas are surgically challenging tumors. Retrochiasmatic craniopharyngiomas with complicated conditions such as large diameter, major calcification, or significant extension to the third ventricle or posterior fossa present surgical challenges; moreover, recurrent retrochiasmatic craniopharyngiomas are particularly formidable challenges. Although the transpetrosal approach to retrochiasmatic craniopharyngiomas published by Hakuba in 1985 can provide unique advantageous exposure of the retrochiasmatic area to allow safe neurovascular dissection and facilitate radical tumor removal, the procedure is viewed as complicated and time consuming and has a high risk of damaging hearing functions. The authors have modified Hakuba's technique to minimize petrosectomy and reduce surgical complications and have applied this modified approach to retrochiasmatic craniopharyngiomas with complicated conditions. In this study, the authors describe their technique and surgical outcomes to elucidate the role of this modified transpetrosal approach for retrochiasmatic craniopharyngiomas with complicated conditions. This is the first study to report surgical outcomes of the transpetrosal approach for retrochiasmatic craniopharyngiomas. Between 1999 and 2011, the minimum anterior and posterior combined (MAPC) transpetrosal approach, which is a modification of Hakuba's transpetrosal approach, was applied in 16 cases of retrochiasmatic craniopharyngiomas with complicated conditions. Eight cases were recurrent tumors, 4 had previously received radiotherapy, 11 had a large diameter, 10 had large calcification, 15 had superior extension of the tumor into the third ventricle, and 10 had a posterior extension of the tumor that compressed the midbrain and pons. In all 16 patients, more than 2 of these complicated conditions were present. The follow-up duration ranged from 0.8 to 12.5 years (mean 5.3 years). Surgical outcomes assessed were the extent of resection, surgical complications, visual function, endocrinological status, and neuropsychological function. Five-year and 10-year recurrence-free survival rates were also calculated. Gross-total or near-total resection was achieved in 15 cases (93.8%). Facial nerve function was completely maintained in all 16 patients. Serviceable hearing was preserved in 15 cases (93.8%). Visual function improved in 13 out of 14 cases (92.9%) that had visual disturbance before surgery. None of the patients experienced deterioration of their visual function. Twelve cases had endocrinological deficit and received hormonal replacement before surgery. New endocrinological deficit occurred in 2 cases (12.5%). Neuropsychological function was maintained in 14 cases (87.5%) and improved in 1 case (6.3%). One case that had received previous conventional radiotherapy treatment showed a gradual decline in neuropsychological function. The 5-year and 10-year recurrence-free survival rates were both 86.5%. The authors obtained good results by using the MAPC transpetrosal approach for the removal of retrochiasmatic craniopharyngiomas with complicated conditions. The MAPC transpetrosal approach should be considered as a therapeutic option for selected cases of retrochiasmatic craniopharyngiomas with complicated conditions.

Dumbbell-Shaped Abducens Schwannoma: Case Report

Schwannomas of the abducens nerve are uncommon. Nineteen cases have been reported in the literature and are classified into two types: Type 1, in the cavernous sinus, and Type 2, in the prepontine area. However, a dumbbell-shaped type has not yet been reported. Here we report the first case of a dumbbell-shaped abducens schwannoma and classify this type into a new category (Type 3). A 36-year-old woman presented with left hearing disturbance for 4 years, dizziness for 2 years, and dysphagia for 6 months. Neurological examination showed left sensorineural hearing impairment, hypesthesia in the distribution of the left first and second branches of the trigeminal nerve, left curtain sign, and gait disturbance. Computed tomography and magnetic resonance imaging revealed a dumbbell-shaped tumor located in the cavernous sinus that extended to the right cerebellopontine angle. She underwent a two-staged operation; the first operation was via ananterior transpetrosal approach for the lesion in the middle fossa and the upper part in the posterior fossa, and the second surgery was via alateral suboccipital approach for the lower part in the posterior fossa. In the first operation, the abducens nerve was sacrificed. Histological examination confirmed schwannoma. Postoperatively, hearing disturbance and ataxia were improved and complete abducens nerve paresis appeared. The dumbbell-shaped abducens schwannoma has novel clinical features, difficulty of sixth nerve preservation, and unique surgical approach.

Double Plombage Using Abdominal Adipose Tissue for Posterior Transpetrosal Approach–induced Liquorrhea

Objective: To prevent posterior transpetrosal approach–induced liquorrhea, we developed a method involving the double application of abdominal adipose tissue in the subdural and epidural spaces. Materials and Methods: The method was applied to 8 patients who underwent surgery under a posterior transpetrosal approach: 4 with petroclival meningioma and 1 each with tentorial meningioma, jugular foramen neurinoma, trigeminal neurinoma, and metastatic brain tumor. The combined transpetrosal approach was used for 6 patients and the combination with the lateral suboccipital approach was used for the other 2 patients. After tumor resection, the divided dura mater of the presigmoid space was closed as follows: first, a fat mass excised from the abdominal region was divided into 2 parts, and several excisions were made in each part to flatten them. The exposed brain surface was covered with the flattened fat, and the fat margin was circumferentially inserted under the dura mater. The division was then closed by suturing the dural stumps at several sites, loading tension to some extent. Finally, the other part of the adipose tissue was spread in the epidural space in the dural-defective region for double closure inside and outside the dura mater. Results: Liquorrhea was prevented in all patients. Conclusions: It was concluded that this method is useful to prevent postoperative liquorrhea induced by a posterior transpetrosal approach.

Combined extradural subtemporal and anterior transpetrosal approach to tumors located in the interpeduncular fossa and the upper clivus

Central skull base lesions in the interpeduncular fossa and the upper clival regions can be challenging to access because of their location anterior to the brainstem. We have modified the anterior transpetrosal approach by combination with the extradural subtemporal route to increase the surgical corridor. Thirty-seven patients underwent surgical treatment via the anterior transpetrosal approach from 2002 to 2012. The combined surgical approach was primarily applied when the tumors arose from the upper clival portion and extended to the interpeduncular fossa. The combined approach was used in seven of these patients, comprising four patients with petroclival meningiomas, one patient with sphenoclival meningiomas, one patient with trigeminal schwannoma, and one patient with an epidermoid cyst extending from the interpeduncular fossa to the prepontine cistern. The combined approach permitted excellent visualization of the interpeduncular fossa in addition to the upper clivus and the lateral aspect of the brain stem. Mobilization of the temporal lobe by the entire epidural dissection of the lateral wall of the cavernous sinus facilitates access via the subtemporal route. The transient symptom of the temporal lobe in the dominant site may be the only drawback for this combined approach, although it may disappear immediately after the surgery. The present approach combines Dolenc's approach and Kawase's approach, providing a wide exposure to lesions of the interpeduncular fossa and the clivus.

“Extended” Retrosigmoid Approach for Cerebellopontine Angle Tumors with Middle Fossa Extension

Background: Various transpetrosal approaches have been described for removal of tumors extending from the posterior fossa into middle fossa. However, these approaches are associated with significant morbidity and affect the quality of life.

The High Road or the Low Road

n this wonderful article, which combines cadaver dissection with case illustrations, a group of pioneering endonasal I surgeons describe their decision-making strategy in choosing between the endonasal “farmedial” approach and the transcranial “far lateral” approach to the cervicomedullary junction. Articles such as these, of which there are several, represent a healthy fourth stage in theevolutionof theendonasal approaches. This first stage, which can be called Introduction, was the presentation of the endonasal approaches involving cadaver dissection and case reports. This first stage was met with skepticism among the neurosurgical community, leading to the second stage, which can becalled Justification. In this stagesurgeonspresented larger case series showing safety and efficacy. This stage was met with curiosity and early adoption, as well as harsh criticism of complications, which required a third stage, namely Modification. In this stage the endonasal approaches and instrumentationwere altered to further reduce complications and increase efficacy.We are now entering a new stage, in which the endonasal approaches are considered safe and effective in experienced hands and the main issue becomes appropriate selection of the proper approach. This stage involves decision-making algorithms, direct comparisons between endonasal and transcranial approaches (2-8), and frank discussions of the benefits and limitations of the endonasal versus the transcranial approaches. These last set of articles, ofwhich the current article represents an excellent example, include comparisons of the pterional, supracilliary versus endonasal transplanum approaches, or the transpetrosal, subtemporal versus endonasal transpterygoidal approaches, or extended transbasal versus endonasal transcribriform approaches. The purpose is not to show that one approach is better than another, but rather to indicate in what situations one approach might be preferable and when the

Importancia neuroquirúrgica del complejo venoso petroso superior

To study the microsurgical anatomy of the superior petrosal venous complex (SPVC). We conducted a descriptive and prospective study. Six injected specimens were used (12 sides). The microsurgical anatomy of the SPVC was studied by means of an anterior, retrosigmoid and transpetrosal approach. Neurosurgical equipment, 0-degree rigid endoscopy and OPMI-1 surgical microscope with 6× to 20× magnification were all used in this study. The venous drainage pattern toward the superior petrosal sinus was analysed, as were the formation of tributary veins, the relationship with the trigeminal nerve and the anatomical variants of SPVC. The SPVC was present in all cases. A tributary, cerebellopontine fissure vein was identified in 100% of cases. The venous drainage pattern of the SPVC was divided into medial, intermediate and lateral with respect to the suprameatal crest. The SPVC was simple in 8 sides and duplicate in 4 sides. A triangle formed by the tentorium, the SPVC and part of the tentorial and petrosal surface of the cerebellum was also observed in the study. This triangle was called the petrosal-tentorial triangle. It is important to understand the microsurgical anatomy of the SPVC. Therefore, we propose the petrosal-tentorial triangle as a neurosurgical route for the management of pathologies from the cerebellopontine angle to the superior petroclival region.

62. 椎骨脳底動脈合流部動脈瘤に対するTranspetrosal approach

62. 椎骨脳底動脈合流部動脈瘤に対するTranspetrosal approach

Classification of petroclival meningiomas and selection of surgical approach

Objective To analyze the classification of petroclival meningiomas according to the tumor extension on magnetic resonance imaging ( MRI ) and choice of surgical approach.Methods The clinical data of 318 cases of petroclival meningiomas were retrospectively analyzed.The cases were classified into eight types:petrous apex,cavernous sinus,sphenopetrosal,petroclival,petroclival - cavernous sinus,cerebellopontine angle (CPA),clival and extensive types.The pre- and post -operative statuses were evaluated by Karnofsky Performance Scale (KPS).Results 248 patients were included in the study with a mean preoperative KPS of 73.7 ± 10.3. The most frequent approaches were presigmoid transpetrosal approach (49.6％) followed with subtemporal transpetrosal and transtentorial approach/ Kawase' s approach (STTA/KA) (35.1％ ).Complete resection (Simpson Grade Ⅰ or Ⅱ ) was achieved in 52.4％ patients.The most frequent approach of the first three types was STTA/KA ( 53.7％ ) and presigmoid transpetrosal approach (63.8％) in the latter five types,and the different proportion of approaches used between the two groups was significant (x2 =27.461,P ＜ 0.001 ).The complication rate of cranial nerves Ⅵ,Ⅶ and Ⅷ of presigmoid transpetrosal approach was higher than that of STTA/KA.The recent KPS was 75.8 ±26.9 without statistical difference from preoperative KPS (t =- 1.321,P =0.188 ).Compared with preoperative status,57.7％ patients were improved and 19.0％ were stabilized at recent evaluation.Conclusions Classification of petroclival meningiomas will contribute to the approach selection.STTA/KA approach is fit for the first three types,meanwhile,presigmoid transpetrosal approach is suitable for the latter five types. Comprehensive preoperative evaluation is essential to achieve individualized treatment and favorable prognosis. Key words: Meningioma; Petroclival; Presigmoid approach; Subtemporal approach; Classification

Posterior fossa meningioma (surgical experiences)

IntroductionMeningioma is a common tumor that represents about 30% of all intracranial tumors. Posterior fossa location of the tumor is uncommon. It can be classified according to the location in the posterior fossa into cerebellopontine angle, clival, petroclival, convexity, tentorial and foramen magnum. Different surgical approaches are used to excise these tumors. Aim of the studyWas to study different aspects of posterior fossa meningioma regarding location, histology, surgical approaches and outcome. MethodsRetrospective study including 20 patients diagnosed with posterior fossa meningioma was included in the study. Data were obtained from the files of the patients and were analyzed. All patients had preoperative complete general and neurological examination, MRI of the brain with and without Gadolinium. Different surgical approaches were utilized in the study depending on the tumor location and the surgeon's preference. Postoperatively, all patients had a postoperative CT scan of the brain with contrast. Some patients had also MRI of the brain with and without Gadolinium. ResultsFifteen of the patients were females and 5 were males. The age ranged from 35 to 69. Symptoms included headache (75%), cerebellar manifestations (60%), cranial nerve affection (40%) and hearing disturbances (15%). Most of the cases (50%) were cerebellopontine angle meningioma while the least (5%) were foramen magnum meningioma. Surgical approaches used included retrosigmoid approach (50%), transpetrosal approach (30%) and transcondylar approach (20%). Tumor removal was total in 60% of cases and partial in 40%. Postoperative mortality was present in 5% of cases. Morbidity included decreased level of consciousness, cranial nerve palsy and wound infection. ConclusionRetrosigmoid approach is effectively and safely used for cerebellopontine angle meningioma, convexity menigioma and lateral tentorial meningioma extending inferiorly to the posterior fossa. Suboccipital approach can be used safely for posterior foramen magnum meningioma. Clival and petroclival meningioma carry a high morbidity incidence.

Epidural anterior petrosectomy with subdural visualization of sphenobasal vein via the anterior transpetrosal approach—technical case report

The drainage of the superficial middle cerebral vein (SMCV) is classified into four subtypes. The sphenobasal vein (SBV) drains from the SMCV to the pterygoid venous plexus at the temporal skull base. Epidural procedures in the standard anterior transpetrosal approach (ATPA) may damage the route of the SBV. We report a case in which modified surgical procedures via the ATPA were used to preserve the SBV. A 45-year-old man complained of right facial pain. Magnetic resonance images revealed a right cerebellopontine tumor suggestive of an epidermoid cyst. Right carotid angiography revealed that the SMCV drained into the pterygoid venous plexus via the SBV. The convexity dura mater of the temporal lobe was cut and the anterior part of the temporal lobe was retracted subdurally. The SBV was visualized from the subdural side. The basal dura mater of the temporal lobe posterior to the SBV was cut and the posterior part of the temporal lobe was retracted epidurally. After dissecting the dura mater medial to the greater petrosal nerve and to the edge of the petrous apex, the petrous apex was exposed and drilled out without injuring the SBV. The superior petrous sinus and the tentorium were cut. The tumor compressed the root exit zone of the trigeminal nerve. The tumor was grossly totally removed. The modified ATPA (epidural anterior petrosectomy with subdural visualization of the SBV) is effective in preserving the SBV.

Resection of Petroclival Meningiomas Using a Combined Transpetrosal Approach: Surgical Outcomes in 65 Patients and Evaluation of a New Scoring System for Patient Conditions.

Resection of Petroclival Meningiomas Using a Combined Transpetrosal Approach: Surgical Outcomes in 65 Patients and Evaluation of a New Scoring System for Patient Conditions.

The Suboccipital Transtentorial Approach: Indications, Technique, and Outcomes in Five Illustrative Cases

Introduction: The suboccipital retrosigmoid approach is an effective alternative to transpetrosal approaches to petroclival meningiomas. Samii modified this with a retrosigmoid intradural suprameatal approach to increase access to the middle fossa and Meckel's cave. More recently, Watanabe et al modified this by preferentially dividing the tentorium with limited drilling of the suprameatal bone, which they termed the “lateral supracerebellar transtentorial approach.” Poppen introduced sectioning of the tentorium via an occipital approach for pineal region pathology. We present our experience with a suboccipital transtentorial approach.

Microsurgery for large and giant petroclival meningioma

Objective To summarize the experience of microsurgical removal of large and giant petroclival meningiomas.Methods The clinical data of 26 patients of large or giant petroclival meningiomas were collected.7 cases were conducted through subtemporal transpetrosal approach,15 retrosigmoid,2 supra -infratentorial (subtemporal and retrosigmoid sinus combined approach ) and 2 orbitozygomatic approach.Results Gross total resection (Simpson Grade Ⅰ or Ⅱ )was achieved in 13 patients,subtotal resection ( Simpson Grade Ⅲ) in 4,and partial resection ( Simpson Grade Ⅳ ) in 9.Conclusions To avoid blind pursuing total resection of tumors,and to seek to the balance between the extent of tumor resection and reducing postoperative complications,different surgical approaches should be chosen according to the types,size,growth patterns and encroachment areas of large and giant petroclival meningiomas. Key words: Meningioma; Petroclivus; Microsurgery

Endolymphatic Sac Tumors

Tumors of the endolymphatic sac are rare and can be found in patients with Von Hippel Lindau disease. They most often develop within the intrapetrosal part of the sac but can sometimes be located in the distal part. Their growth is slow and they spread in two directions: laterally toward the external and middle ear and in the direction of the jugular foramen and medially into the ponto-cerebellar angle. The symptoms are usually auditive, with a constant neurosensorial deafness of sudden onset in 50 % of cases and sometimes associated with a tinnitus and dizziness. The varieties with medial extension result in a cerebellopontine angle syndrome. Diagnosis is made by imaging (CT scan and MRI) that reveals a heterogeneous tumor between the lateral sinus and the internal auditory meatus, hypervascularized showing contrast, with cystic zones and associated with bone lysis. Histological examination of a papillary cystadenoma is performed and the differential diagnosis is essentially made with a papillary of the choroïd plexus. They require total surgical excision in order to avoid possible recurrence and can be performed by retrosigmoïd approach, or more ideally, by transpetrosal approach.

Vestibular Monitoring via Abducens EMG: Observations on a Single Case

Advancement in skull base surgery has occurred due to the improved ability to remove larger and less accessible tumors while minimizing morbidity. Petroclival meningiomas represent a particular challenge due to their proximity to and involvement with multiple cranial nerves. Intraoperative neural monitoring has become routine in assisting the surgeon to avoid injury to these structures. We present a case of a large petroclival meningioma removed by a transpetrosal approach with intent of hearing preservation in which an interesting finding was obtained from neural monitoring. In addition to facial, trigeminal, SSEP, and BAER monitoring, continuous EMG monitoring of the abducens nerve was performed. During the transmastoid approach, an opening was inadvertently made in the lateral semicircular canal. With the membranous labyrinth intact, it was decided to pack the canal to prevent further injury. The cupular deflection caused by the packing resulted in a rhythmic repeated firing of the ipsilateral abducens, representing the correcting saccades of the induced nystagmus. This confirmed that the vestibular apparatus, local brainstem, and nerve were intact and functional, as ablative nystagmus would have been in the opposite direction. This was confirmed further by there being no change in the wave I or V of the BAER. For the remainder of the case, the rhythmic firing of the abducens nerve served as a monitor of the health of both the VI and VIII nerves. Tumor involvement at the brainstem insertion of the VIII nerve eventually resulted in the loss of this phenomenon, mirroring the findings on BAER. It is felt that this phenomenon may be exploited in future selected cases to provide real-time feedback on the health of the vestibular nerve during skull base surgery.