Presigmoid sinus approach to petroclival meningiomas

Between August 1987 and May 1989 five patients with petroclival meningiomas were operated on at the Neurosurgical Clinic of the Krankenhaus Nordstadt. Hannover, Germany, using an original combined supra- and infratentorial presigmoid sinus approach. There were two men and three women, ranging in age from 34 to 61 years (mean, 48 years; median, 46 years). Follow-up ranged between 1 and 22 months. There was no death. Postoperatively, two patients had no useful hearing, one had a permanent facial palsy (the facial nerve had to be sacrificed intraoperatively due to its involvement with tumor), one had a permanent abducens palsy (the VI nerve was involved with tumor and had to be cut). Temporary lower (IX to XII) cranial nerve palsy was observed in all the patients; temporary VI, in two patients; temporary VII, in two patients, temporary hemiparesis, in one patient, temporary gait ataxia, in three patients; and persistent gait ataxia, in one patient. All patients had total tumor removal as assessed at surgery and with postoperative enhanced computed tomography. Four patients were independent and able to carry on normal activity, and one patient was independent at home but not outside due to severe ataxia 4 months after the operation. The presigmoid sinus avenue to the petroclival region shortens the distance to the clivus, permits a multiangled exposure of this difficult surgical area, minimizes the amount of temporal lobe retraction, preserves the integrity of the transverse sinus, and allows for better preservation of the neurovascular structures. These factors translate into a high percentage of total tumor removal and a low incidence of permanent morbidity.     

Petrosal approach for petroclival meningiomas

Thirteen patients harboring large petroclival meningiomas are reported. The evolution of the petrosal approach is discussed, and modifications for improvement in surgical technique are described. There was no mortality in this series, and total removal was achieved in all but two patients. Morbidity included cranial nerve deficit, pulmonary embolism, and hemiparesis.     

岩斜部脑膜瘤的微侵袭治疗

目的探讨微侵袭神经外科技术在岩斜脑膜瘤治疗中的应用。方法采用锁孔技术治疗14例岩斜部脑膜瘤。累及上中斜坡8例，广基或宽基累及上中下斜坡5例，累及中下斜坡1例其中6例同时扩展至鞍旁或海绵窦内，采用枕下乙状窦后锁孔入路6例，颞下锁孔入路2例，幕上下联合入路6例。结果全切除肿瘤8例，次全切除4例，大部切除2例(均为术后复发患者)。术后神经功能完好或未见新增脑神经损伤8例，术后出现轻度面瘫4例，外展功能障碍3例，动眼神经麻痹2例，后组脑神经功能影响1例，均未发生术后脑脊液漏和切口感染经11～19个月随访，轻度面瘫和动眼神经麻痹均有明显改善，但外展功能障碍恢复缓慢。结论针对岩斜部脑膜瘤累及范围，采用单独／联合采用颞下锁孔入路和枕下乙状窦后锁孔入路可有效切除肿瘤，并可减少手术创伤，缩短手术和患者康复时间，减少术后并发症。联合运用微侵袭技术(锁孔入路联合)，术中显微技术与术后放射外科治疗等是今后岩斜部脑膜瘤的治疗方向。     

Classification and quantification of the petrosal approach to the petroclival region

OBJECT: The petrosal approach to the petroclival region has been used by a variety of authors in various ways and the terminology has become quite confusing. A systematic assessment of the benefits and limitations of each approach is also lacking. The authors classify their approach to the middle and upper clivus, review the applications for each, and test their hypotheses on a cadaver model by using frameless stereotactic guidance. METHODS: The petrosal approach to the upper and middle clivus is divided into four increasingly morbidity-producing steps: retrolabyrinthine, transcrusal (partial labyrinthectomy), transotic, and transcochlear approaches. Four latex-injected cadaveric heads (eight sides) underwent dissection in which frameless stereotactic guidance was used. An area of exposure 10 cm superficial to a central target (working area) was calculated. The area and length of clival exposure with each subsequent dissection was also calculated. The retrolabyrinthine approach spares hearing and facial function but provides for only a small window of upper clival exposure. The view afforded by what we have called the transcrusal approach provides for up to four times this exposure. The transotic and transcochlear procedures, although producing more morbidity, add little in terms of a larger clival window. However, with each step, the surgical freedom for manipulation of instruments increases. CONCLUSIONS: The petrosal approach to the upper and middle clivus is useful but should be used judiciously, because levels of morbidity can be high. The retrolabyrinthine approach has limited utility. For tumors without bone invasion, the transcrusal approach provides a much more versatile exposure with an excellent chance of hearing and facial nerve preservation. The transotic approach provides for greater versatility in treating lesions but clival exposure is not greatly enhanced. Transcochlear exposure adds little in terms of intradural exposure and should be reserved for cases in which access to the petrous carotid artery is necessary.     

The middle fossa transpetrous approach for petroclival meningiomas

Seventeen patients with petroclival meningioma were operated on through a middle fossa transpetrous approach. This approach exposes the anterior cerebellopontine angle through a middle fossa craniotomy with removal of the petrous apex medial to the cochlea and petrous carotid artery. This approach may be enlarged by transection of the superior petrosal sinus and tentorium. The surgical technique and application of the middle fossa transpetrous approach for petroclival meningiomas is presented.     

枕下乙状窦后-内听道上入路切除岩斜区脑膜瘤

目的介绍应用枕下乙状窦后-内听道上入路显微手术切除岩斜区脑膜瘤的显微手术技术。方法回顾性分析采用枕下乙状窦后-内听道上入路显微手术治疗的8例岩斜区脑膜瘤的临床资料,并对手术方法进行分析。结果肿瘤全切除6例,次全切除2例。术后新增脑神经损害2例,无手术死亡病例。结论枕下乙状窦后-内听道上入路是切除主体位于后颅窝、同时累及中颅窝的岩斜区脑膜瘤的安全有效的改良入路,娴熟的显微神经外科技术,熟练掌握入路的显微解剖可获得满意的手术疗效,有利于提高肿瘤切除率和疗效。     

Natural history of petroclival meningiomas

OBJECTIVE: For evaluation of the natural history of petroclival meningiomas, a cooperative retrospective study of 21 conservatively treated patients is reported. METHODS: All patients had petroclival meningiomas that were observed for at least 4 years, with regular clinical and radiological control examinations. The follow-up periods ranged from 48 to 120 months (mean, 82 mo; median, 85 mo). Functional evaluations were performed by using the Karnofsky index. Individual growth curves and rates were defined. RESULTS: Age and sex distributions and presenting symptoms were comparable to those of other studies. During follow-up monitoring, radiological tumor growth was observed in 76% of the cases. With 63% of the growing tumors, there was functional deterioration. We performed statistical analyses of demographic features, radiological findings, and functional deterioration. Severe functional deterioration was observed to be statistically significantly associated with infratentorial growth and increased growth rates. A change in the growth pattern often preceded functional deterioration. CONCLUSION: This study provides a better understanding of the natural course of petroclival meningiomas. The growth patterns of these tumors are unpredictable and variable. The exact factors influencing growth remain unclear. This study can contribute to the optimization of individual management of these tumors.     

Surgical removal of small petroclival meningiomas

Summary Treatment of large petroclival meningiomas causing brain stem compression is surgical removal followed by radiotherapy or radiosurgery if the lesion was partially resected. The management of small petroclival meningiomas is, however, controversial. Clinical observation, radiosurgery and surgical removal are the options of treatment. The natural history of these tumours is not well known. Published series of patients treated with radiosurgery are not comparable with surgical series because the latter also includes large size tumours. In this paper we present a series of 18 patients with small petroclival meningiomas (diameter ≤ 2.8 cm) treated with radical surgical removal. Total resection (Simpson’s Grade 1) [43] was possible with minimal morbidity and no mortality. Background. We present a series of small petroclival meningiomas (SPM) treated by radical surgical removal and compare the outcome with other management modalities proposed for these lesions. Methods. Eighteen patients with SPM were surgically treated at our department of neurological surgery. The tumours were classified as small when they had a diameter < 3.0 cm. Headaches (n = 12), diplopia (n = 8), facial hypoaesthesia (n = 3) and tinnitus (n = 6) were the most frequent symptoms at presentation. The approaches used were retrosigmoid (n = 14), fronto-orbito-zygomatic (n = 3) and presigmoid (n = 1). The post-operative follow-up ranged from 1 to 110 months (mean 41.8 months). Findings. Radical tumour resection (Simpson’s Grades 1 and 2) was achieved in all patients. There was no major morbidity or mortality related to the surgical procedure. Transient abducent nerve palsy was the only post-operative complication. The pre-operative cranial nerves deficits improved after surgery. Only one patient had persistent diplopia postoperatively. Conclusion. Radical surgical removal of SPM is possible with minimal morbidity and may cure the patient. The effectiveness and outcome of surgery for small petroclival meningiomas should be compared with series treated by radiosurgery. Correspondence: Ricardo Ramina, R. Goncalves Dias 713, 80240340 Curitiba, Brazil.     

Combined subtemporal and retrosigmoid keyhole approach for extensive petroclival meningiomas surgery: report of experience with 7 cases.

OBJECTIVE: The resection of petroclival meningiomas offers great challenges to the neurosurgeon. Surgery via a combined subtemporal and retrosigmoid keyhole approach surgery was evaluated for the treatment of extensive petroclival meningiomas on the basis of our experience with 7 cases. METHODS: From July 2002 to July 2005, the resections of 7 petroclival meningiomas, which involved both supra- and infra-tentorial regions, were performed via a combined subtemporal and retrosigmoid keyhole approach. The extent of tumor resection was evaluated by MRI 3 months after surgery, and postoperative complications were investigated. RESULTS: The maximum diameter of tumors ranged from 3.4 to 6.0 cm (mean: 4.4 cm). Gross total resection (GTR) was achieved in 3 cases, giving a GTR rate of 43%. Subtotal resection (STR) was carried out in 4 cases. Neurological status remained intact in one case, while the others presented with cranial nerve deficits (VII, VI, V, III and lower CN). No death was reported during the postoperative period. CONCLUSION: This combined keyhole approach is suitable for the treatment of extensive petroclival meningiomas. It provides easy and quick access to the supra- and infratentorial juxta-clival regions without any petrous bone drilling. Complications related to the approach can be minimized.     

Two step approach for surgical removal of petroclival meningiomas with large supratentorial extension

The treatment of petroclival meningiomas is still a matter of controversy in literature. In the last decades, many approaches have been introduced. Our strategy for the treatment of such tumors having large supratentorial extension with encasement of the internal carotid artery or compression of optic and oculomotor nerves has evolved in the attempt to improve the outcome. Currently, we favor a surgical technique consisting of two steps. As first step, we perform a retrosigmoid suprameatal approach in order to resect the posterior part of the tumor and obtain brainstem decompression. In the second step, carried out after patient’s recovery from the first surgery, we remove the supratentorial portion of the lesion using a frontotemporal craniotomy to achieve the decompression of the optic nerve, oculomotor nerve, and carotid artery. The retrosigmoid suprameatal approach allows for adequate brainstem decompression: the tumor itself creates a surgical channel increasing the accessibility to the lower and upper petroclival surface. Moreover, this route allows for early visualization of cranial nerves in the posterior fossa and safe tumor removal under direct visual control, reducing the risk of postoperative deficits. Via the simple and safe frontotemporal craniotomy, the supratentorial part of the lesion can be removed thus avoiding the need of invasive approaches. We propose a two-stage surgery for treatment of petroclival meningiomas combining two simple routes such as retrosigmoid suprameatal and frontotemporal craniotomy. This approach reflects our philosophy to use simple and less invasive approaches in order to preserve neurological function and a good quality of life of the patient.     

Two step approach for surgical removal of petroclival meningiomas with large supratentorial extension

Neurosurgical Review - The treatment of petroclival meningiomas is still a matter of controversy in literature. In the last decades, many approaches have been introduced. Our strategy for the...     

幕上下联合锁孔入路显露岩斜区的显微解剖

目的 研究颞下和枕下乙状窦后锁孔入路对岩斜区显露的互补性.方法 尸头上模拟该锁孔入路,颞部骨窗以颧弓根部为中心前后各1.5 cm,高2.5 cm,枕下乙状窦后骨窗直径3 cm,观察显露范围并用导航标记.用带有造影剂的明胶海绵标记适于操作的有效空间,再行CT扫描和三维重建.结果 颞下入路从前外侧到达岩斜区,对颅中窝、鞍旁、幕上桥前池、脚间池下部、环池前部显露佳,切开小脑幕后环池和桥前池下部视野得到扩展,桥小脑角池方向被岩尖遮挡,是显露的死角.枕下乙状窦后入路从后外侧到达岩斜区,对同侧桥小脑角、桥前池、环池后部显露佳,但Meckel's囊开口至海绵窦后部被内听道上结节遮挡,范围小于1 cm3.结论 颞下和枕下锁孔入路的显露空间和角度有互补性,联合运用有利于切除同时累及幕上下,侵犯上斜坡和中下斜坡的岩斜脑膜瘤,尽管对海绵窦后部显露不佳,但范围小,处于放射外科的有效治疗范围之内,达到微创疗效.     

Extended lateral subtemporal approach for petroclival meningiomas: report of experience with 24 cases

Subtemporal craniotomy centred on the external ear canal and its basal extension, involving resection of the roots of the zygomatic arch, roof of the external ear canal and superior third to half of the mastoid bone was used to treat surgically 24 meningiomas located in the petroclival region, having their maximum bulk at the level of tentorium. The approach was found to be suitable for dealing with middle fossa extensions of the tumour in addition to the part extending up to the mid-clivus or vertebrobasilar junctional region. The direction of the approach to the petroclival region was the shortest and most perpendicular from surface and avoided any neural or vascular exposure or manipulation. The basal exposure was horizontally wide and significantly low, which reduced the operating distance, limited the extent of temporal lobe retraction and provided additional space for manipulation of instruments. The exposure was manoeuverable with anterior, posterior and medial expansion being possible during or prior to tumour resection. The approach had the advantage of being simple and relatively quick, and of its familiarity to general neurosurgeons. The experience with the approach with petroclival meningiomas and its possible advantages over other available approaches to these lesions are analysed in this report.     

Surgical resection of large and giant petroclival meningiomas via a modified anterior transpetrous approach

The authors describe a modified anterior transpetrous approach (ATPA) for the surgical resection of 21 cases of petroclival meningiomas (PCMs). Briefly, a curved periauricular skin incision was used. The cerebellar tentorium and the dura on the petrous apex were coagulated and incised to expose the petrous apex bone fully. The drilling of the petrous apex bone was performed subdurally and began internally from the trigeminal impression, not exceeding 1.5 cm laterally, not exceeding 6 mm from the posterior edge of the petrous ridge, and not exceeding 8 mm in depth from the surface of the petrous bone. The tumors were removed totally in 12 (57.1 %) cases, subtotally in 8 (38.1 %) cases, and partially in 1 (4.8 %) case. The transient neurological deficit includes mild oculomotor nerve palsy in three cases, abducens nerve palsy in six cases, language disorder in three cases, and mild hemiplegia in two cases. Facial numbness became worse postoperatively in six patients, and only two patients improved at 6 months after surgery. No death occurred in this series. The modified ATPA is an efficient treatment alterative for large or giant PCMs located at the medial and superior internal acoustic meatus with relatively low risk of complications.     

Anatomic-topographic peculiarities of sub- and supratentorial petroclival meningiomas

The data about anatomic-topographic peculiarities of petroclival sub- and supratentorial meningiomas were presented. There were operated on 24 patients, of them 5 have died. Three main topographoanatomic variants were delineated, depending on the tumor primary origin and topographic peculiarities present. The most frequent variant of the tumor localization was a lower one. Depending on the variant of the tumor localization present, the peculiarities of interrelationship between the tumor and nerves, vessels and the brain stem are determined.     

Experience with 36 surgical cases of petroclival meningiomas

Summary Thirty-six patients with petroclival meningiomas underwent surgery between 1978 and 1990. The tumours accounted for 13% of a total of 284 skull base meningiomas operated upon during the same time period. The most frequent neurological signs related to cranial nerve deficits, mainly of the 8th, 5th, and 7th nerves respectively. The approaches to the petroclival region were: retromastoid, pterional, subtemporal, and combined retromastoid-subtemporal. In 12 patients we used a modification of the retromastoid-subtemporal approach with preservation of the sigmoid and transverse sinus (presigmoid approach). Total tumour removal was achieved in 27 cases (75%). There was no postoperative death, and in 83% of cases no severe morbidity. With careful pre-operative evaluation, improved operative approaches and microsurgical techniques the treatment of petroclival meningiomas has been considerably improved.Presented at the EANS-Wintermeeting on High Risk Neurosurgery, Budapest, February 20–23, 1991.