岩斜区肿瘤手术入路选择的探讨

目的 探讨岩斜区肿瘤的手术入路选择。对53例岩斜区肿瘤患者的手术治疗进行分析。方法患者采用颞底经天幕入路11例,枕下乙状窦后入路12例;（颧弓或眶颧）翼点入路12例;乙状窦前入路2例;颞底、乙状窦后幕上下联合入路7例;颞下前岩骨硬膜外入路7例;扩大的前颅底硬膜外入路2例。结果32例（61％）患者肿瘤全切除,9例（17％）次全切除,12例（22％）大部切除。术后新发生颅神经功能障碍16例（30％）,死亡2例（4％）。结论枕下乙状窦后入路、颞底经天幕入路等岩斜区手术入路均可以在熟练的显微操作技术及神经导航、神经内镜下进行。主体生长于硬膜外的岩斜肿瘤适合于采用硬膜外入路手术切除。幕上下联合入路对巨大岩斜区肿瘤是理想的手术入路。     

显微手术治疗三叉神经鞘瘤

目的 总结各种类型三叉神经鞘瘤手术入路的优缺点。方法 回顾分析１９８０年４月￣１９９７年６月手术治疗的３４例三叉神经鞘瘤的临床效果。结果 肿瘤完全位于中颅窝的３例,均采用颞下入路切除,肿瘤位于后颅窝的１３例,１０例经枕下入路,２例采用颞下经小脑幕入路,１例经乙状窦前入路切除。另１８例哑铃型肿瘤中１４例采用颞下经小脑幕入路,４例采用经颞下－乙状窦前入路切除。结论 颞下入路适用中颅窝型肿瘤切除,枕下入     

巨大型岩斜脑膜瘤的手术策略

目的探讨巨大型岩斜脑膜瘤的手术策略。方法回顾性分析32例直径超过4.5cm的岩斜脑膜瘤患者手术及预后情况。将患者分为枕下乳突后入路组与颅底外科乙状窦前入路组,对其手术时间、肿瘤切除情况、及术后神经功能损伤情况进行对比研究。结果枕下乳突后入路组肿瘤全切除率及次全切除率分别为43%、36%;乙状窦前入路组分别为39%、22%,两组差异无显著性意义（P＞0.05）,但枕下乳突后入路组患者神经功能后遗症的发生率较乙状窦前入路组低且症状轻,Karnofsky预后评分较高［枕下乳突后入路组为(75±18)分,乙状窦前入路组为(49±26)分］,两组差异有显著性意义(P＜0.01)。结论巨大型岩斜脑膜瘤患者的肿瘤切除情况与手术入路的选择无明显相关性。枕下乳突后入路手术,在不加重神经功能损伤的前提下,应尽量争取肿瘤全切除;如不能全切除,应缩小瘤体≤3cm,以利术后放射外科治疗,可能是较为安全有效的治疗方案。     

Lateral Suboccipital Retrosigmoid Approach with Tentorial Incision for Petroclival Meningiomas: Technical Note

Introduction The resection of petroclival meningiomas presents great neurosurgical challenges. Although multiple surgical approaches have been developed, the retrosigmoid route tends to be used to address tumors that are predominantly located in the posterior fossa. Our modification of the lateral suboccipital retrosigmoid approach with the placement of a tentorial incision yields good visualization of the supratentorial part of the tumor around the midbrain. Methods We treated four patients, one with primary and three with recurrent petroclival meningioma, by our modified approach. After lateral suboccipital craniotomy, the infratentorial part of the tumor was removed after detaching it from the tentorial surface. The cerebellar tentorium was then carefully incised from the supracerebellar angle, taking care not to damage the superior cerebellar artery and trochlear nerve. Results The operative field surrounding the midbrain was widened by this procedure, and safe dissection of the tumor from the brainstem and other neurovascular structures was performed with direct observation of the interface. Conclusions Our approach is a useful modification of the retrosigmoid approach to petroclival meningiomas. It facilitates the safe resection of the supratentorial part of the tumor in the ambient cistern behind the tentorium.     

双骨瓣成形在乙状窦前入路脑肿瘤切除术中的应用(附14例报告)

目的探讨经岩骨-乙状窦前入路切除岩斜区肿瘤双骨瓣成形的临床效果。方法对14例岩斜区肿瘤采用经岩骨-乙状窦前入路行肿瘤切除双骨瓣成形术,先取颞枕游离骨瓣(乙状窦后),再通过磨钻,游离出乳突表面骨瓣(乙状窦前)。保留骨性半规管、耳蜗的完整性,避免将乳突及岩骨根部大部分切除。结果肿瘤全切除8例,次全切除3例,部分切除3例。术后2例脑脊液耳漏,无皮下积液、颅内感染等并发症,无死亡。14例术后3、6个月随访,无并发症发生。结论经岩骨-乙状窦前入路手术中采用双骨瓣成形术后脑脊液漏、皮下积液、颅内感染等并发症少,手术创伤小,安全性高。     

Motor evoked potential mapping and monitoring by direct brainstem stimulation. Technical note

Motor evoked potentials (MEPs) by direct brainstem stimulation were generated during 12 neurosurgical operations performed in five posterior fossa tumors, six vertebrobasilar aneurysms, and an arachnoid cyst. The anterior aspect of the brainstem was exposed using a subtemporal approach (in six cases), a presigmoid approach (one case), or a lateral suboccipital approach (five cases). A train of five monopolar 5 to 25 mA pulses was then applied, and MEPs were recorded from the extremities. Motor evoked potentials were recorded in all patients (four mappings and seven monitorings) except in a 12-year-old child who underwent surgery for a posterior cerebral artery aneurysm. Although he experienced postoperative motor palsy, the aneurysm ruptured before electrodes could be placed. Two patients with postoperative motor palsy, one with a clival meningioma and one with a basilar trunk aneurysm, had shown significant decreases in MEP amplitude and even complete disappearance of MEPs during intraoperative brainstem stimulation. Motor evoked potentials elicited by direct brainstem stimulation seem to be an accurate neurophysiological monitoring method during operations around the anterior and lateral aspects of the brainstem.     

Surgical approach for jugular foramen neurinoma--combined suboccipital and infralabyrinthine approach using a rotatable head holder

A 36-year-old male with jugular foramen neurinoma was operated upon using a rotatable head holder, which enables the surgeon to rotate the patient's head at any time during the procedure and to gain access in multiple directions to the tumor. The tumor was situated primarily in the jugular foramen and showed partial extension into intracranial as well as into extracranial space. The patient was placed in the lateral position with a rotatable head holder, which allows rotation of the patient's head with the range of 10 degrees face up to 80 degrees face down from the horizontal plane. A linear skin incision was made, beginning behind the auricle and extending along the anterior margin of the sternocleidomastoid muscle, and the sternocleidomastoid muscle was divided just below the tip of the mastoid process. During mastoidectomy and suboccipital craniectomy, the patient's head was rotated 15 degrees face down and sigmoid sinus was exposed toward the jugular foramen, meanwhile the posterior fossa dura mater was opened and the intracranial portion of the tumor was removed with the head positioned 45 degrees-60 degrees face down. The patient's head is then turned 30 degrees face down and the facial canal was opened to displace the facial nerve forward. This oblique posterior approach minimized facial nerve displacement and provided excellent exposure of the large tumor rest which was situated mainly in the jugular foramen and partly extended extracranially. The rotatable head holder allows excellent access in multiple directions and is very helpful in approaching to jugular foramen neurinomas which grow primarily in the jugular foramen and extend both into intra- and extracranially.     

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

Background

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.

Methods

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.

Results

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.

Conclusion

The present approach combines Dolenc’s approach and Kawase’s approach, providing a wide exposure to lesions of the interpeduncular fossa and the clivus.     

Partial labyrinthectomy petrous apicectomy approach to the petroclival region: an anatomic and technical study

OBJECTIVE: The petroclival region generally is thought to be an inaccessible area in the intracranial compartment. A number of ways of reaching this area during surgery have been described, including the presigmoid petrosal approach. The partial labyrinthectomy petrous apicectomy approach is a relatively new approach to this region and is a variant of the presigmoid petrosal approach. This study aims to demonstrate the technique and the microsurgical anatomy of the partial labyrinthectomy petrous apicectomy approach and to provide a quantitative study of its exposure to compare it with other common approaches to this region, particularly the presigmoid petrosal approach. METHODS: Bilateral stepwise dissections were performed on 15 formalin-fixed and dye-injected cadaveric heads (30 sides) under x3 to x40 magnification. A temporal craniotomy was performed after a complete mastoidectomy. A partial labyrinthectomy and petrous apicectomy were performed next. The amount of dura exposed was measured before and after the partial labyrinthectomy and the petrous apicectomy. By measuring the angles of exposure, the approach was examined to analyze how much increased access was gained. RESULTS: This approach provided wide exposure to the petroclival region, the cerebellopontine angle, Meckel's cave, the cavernous sinus, and the prepontine region. On average, there was an increase of 10.8 mm in horizontal exposure as compared with the retrolabyrinthine approach. The average angle of vision achieved with the clival pit as the target was 58.9 degrees. In most of the specimens, an area from the IIIrd to the IXth cranial nerves was easily visible without any significant brain retraction. A high jugular bulb did not reduce the exposure. CONCLUSION: The partial labyrinthectomy petrous apicectomy approach converts two narrow tunnels into a wide corridor. It increases the angle of exposure markedly, providing easy and excellent exposure of the otherwise difficult-to-access petroclival region, and it may also preserve hearing.     

Meningovenous structures of the petroclival region: clinical importance for surgery and intravascular surgery

OBJECTIVE: The goals of this investigation were to perform a detailed analysis of petroclival microanatomic features, to investigate the course of the abducens nerve in the petroclival region, and to identify potential causes of injury to neurovascular structures when anterior transpetrosal or transvenous endovascular approaches are used to treat pathological lesions in the petroclival region. METHODS: Petroclival microanatomic features were studied bilaterally in seven cadaveric head specimens, which were injected with colored silicone before microdissection. Another cadaveric head was used for histological section analyses. RESULTS: A lateral or medial location of the abducens nerve dural entrance porus, relative to the midline, was correlated with the course and angulation of the abducens nerve in the petroclival region. The angulation of the abducens nerve was greater and the nerve was closer to the petrous ridge in the lateral type, compared with the medial type. The abducens nerve exhibited three changes in direction, which represented the angulations in the petroclival region, at the dural entrance porus, the petrous apex, and the lateral wall of the internal carotid artery. The abducens nerve was covered by the dural sleeve and the arachnoid membrane, which became attenuated between the second and third angulation points. The abducens nerve was anastomosed with the sympathetic plexus and fixed by connective tissue extensions to the lateral wall of the internal carotid artery and the medial wall of Meckel's cave at the third angulation point. There were two types of trabeculations inside the sinuses around the petroclival region (tough and delicate). CONCLUSION: The petroclival part of the abducens nerve was protected in a dural sleeve accompanied by the arachnoid membrane. Therefore, the risk of abducens nerve injury during petrous apex resection via the anterior transpetrosal approach, with the use of the transvenous route through the inferior petrosal sinus to the cavernous sinus, should be lower than expected. The presence of two anatomic variations in the course of the abducens nerve, in addition to findings regarding nerve angulation and tethering points, may explain the relationships between adjacent structures and the susceptibility to nerve injury with either surgical or endovascular approaches. Venous anatomic variations may account for previously reported cases of subarachnoid hemorrhage with the endovascular approach.     

经岩骨乙状窦前入路显微外科治疗岩斜区肿瘤

目的 探讨岩斜区肿瘤经岩骨乙状窦前入路显微外科治疗的临床疗效。方法 回顾性研究经显微手术治疗的23例岩斜区肿瘤，对肿瘤病理类型、临床和影像学特征、手术入路、手术切除技巧及术后常见并发症的处理进行系统分析。结果 在手术显微镜下肿瘤全切除16例，近全切除4例，大部分切除3例，无手术死亡。结论 经岩骨乙状窦前入路可全切除岩斜区肿瘤。该手术入路对颞叶和小脑牵拉轻，可为岩斜区肿瘤手术切除提供良好的暴露。     

Choice of neurosurgical approach in the treatment of cranial base lesions

The authors describe a series of surgical approaches that they found particularly useful for the exposure and removal of lesions involving the skull base. These are: 1) fronto-naso-orbital approach; 2) frontotemporo-orbito-zygomatic approach; 3) subtemporal transpetrosal approach; 4) temporo-suboccipital transpetrosal approach (retrolabyrinthine presigmoid; transsigmoid; translabyrintine amend transcochlear presigmoid); 5) dorsolateral approach to the foramen magnum and lower clivus.As the approaches are complex and carry potential risks of morbidity, not only it is important to have a good knowledge of basic anatomy but also to closely follow the indications for each one. In this type of surgery where it is often difficult to achieve complete removal of the lesion by a single route of attack, more than one approach may be employed in different surgical steps. Finally, all these approaches demand extremely scrupulos surgical reconstruction to avoid dangerous postoperative complications that may jeopardize the previous work of the surgeon.     

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.     

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

OBJECTIVE: Resection of petroclival meningiomas offers great challenges to the neurosurgeons. Our experience of 7 cases using a combined subtemporal and retrosigmoid keyhole approach surgery was evaluated for the treatment of extensive petroclival meningiomas. METHODS: From July 2002 to July 2005, resections of 7 petroclival meningiomas, which involved both supra- and infratentorial 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 the 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 others presented with cranial nerve deficits (VII, VI, V, III and lower CN). No death was reported in the cases during the postoperative period. CONCLUSION: The combined keyhole approach is suitable for the treatment of extensive petroclival meningiomas. It provides easy and quick access to the supra- and infratentorial juxtaclival region without any petrous bone drilling. Complications related to the approach can be minimized.     

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.     

Microsurgical removal of petroclival meningiomas: a report of 33 patients.

This is a report of 33 consecutive cases of petroclival meningioma treated surgically at our institution over the last 10 years; there were 21 women and 12 men between the ages of 27 and 68 (mean age, 52). All patients were assessed by computed tomographic scans including coronal sections and bone algorithm studies; in most cases, digital subtraction angiography and magnetic resonance imaging were also done. The largest tumor diameter was between 2 and 3.5 cm in 14 cases, 3.5 to 6 cm in 15 cases, and over 6 cm in 4 cases. Dural attachment predominantly involved the clivus and apical petrous bone on one side only; in 14 cases, however, the tumor grew over the clivus midline or crossed the tentorial notch. Cranial nerve deficit was extant in all cases and was commensurate with tumor size. Cerebellar signs and somatic motor deficits were present in 60 and 30% of cases, respectively. The surgical approaches used were the retromastoid-retrosigmoid in 23 cases, subtemporal in 5 cases, and combined retromastoid subtemporal presigmoid in the remaining 5. Total removal was achieved in 26 cases (79%); incomplete removal occurred in 7 cases (21%). The extent of tumor removal and operative morbidity were not significantly related to tumor size. Brain stem indentation, arterial and cranial nerve encasement, and epidural invasion were the main factors that prevented total tumor removal and influenced operative morbidity. There was no intraoperative mortality, but three patients (9%) died perioperatively. In the postoperative period, most patients went through momentary neurological deterioration, chiefly due to new cranial nerve deficits. The average follow-up was 4.3 years in 27 patients; of these 17 were unchanged and 10 were improved. Before surgery, only 13 patients were self-sufficient; at long-term follow-up, another 6 had achieved independence. Our experience suggests that, even though real petroclival meningiomas still represent a formidable surgical challenge, such tumors can in most cases be removed completely with low attendant mortality and acceptable morbidity.     

Microvascular decompression for treatment of trigeminal neuralgia, hemifacial spasm, and glossopharyngeal neuralgia: three surgical approach variations: technical note

OBJECTIVE: We have used three different approaches, namely, the infratentorial lateral supracerebellar approach, the lateral suboccipital infrafloccular approach, and the transcondylar fossa approach, for microvascular decompression for treatment of trigeminal neuralgia, hemifacial spasm, and glossopharyngeal neuralgia, respectively. Each approach is a variation of the lateral suboccipital approach to the cerebellopontine angle (CPA); however, each has a different site of bony opening, a different surgical direction, and a different route along the cerebellar surface. METHODS: The infratentorial lateral supracerebellar approach is used to access the trigeminal nerve in the superior portion of the CPA through the lateral aspect of the cerebellar tentorial surface. The lateral suboccipital infrafloccular approach is directed through the inferior part of the cerebellar petrosal surface to reach the root exit zone of the facial nerve below the flocculus. The transcondylar fossa approach is used to access the glossopharyngeal nerve in the inferior portion of the CPA through the cerebellar suboccipital surface, after extradural removal of the jugular tubercle as necessary. RESULTS: In all three approaches, the cerebellar petrosal surface is never retracted transversely, that is, the cerebellar retraction is never directed parallel to the longitudinal axis of the VIIIth cranial nerve, dramatically reducing the risk of postoperative hearing loss. CONCLUSION: The greatest advantage of the differential selection of the surgical approach is increased ability to reach the destination in the CPA accurately, with minimal risk of postoperative cranial nerve palsy.     

Neurinoma of the trigeminal nerve. Excision by combined suboccipital and pteriono-temporal approach

The authors report a recent personal case of trigeminal neurinoma with a topographical extension both in the cerebello pontine angle and the middle cerebral fossa. This 33 year-old female suffered from progressive sensory disturbances of her right hemiface associated with a right fifth nerve motor deficit, a right VI nerve palsy and a tinnitus. CT scan and angiogram were evocative of a right hourglass trigeminal neurinoma. Two successive operative stage through suboccipital route and a pteriono-temporal extra and intradural approach allowed a complete removal of the tumour. A post-operative rhinorrhea dried up with 10 days. The patient complained with a right hemiface anesthesia and a palsy of the masseter muscles; the VI nerve palsy recovered within 3 months. From the review of the literature (118 cases) the authors summarize the anatomical, clinical and radiological features of these tumours and point out. The difficulty of their surgical removal that was only complete in half of cases. The high frequency of hourglass neurinomas explains that a single suboccipital or subtemporal approach--even with opening of the tentorium--only allowed 23 complete removal among the 58 published or quoted interventions. This justifies that in a majority of cases a combined approach must be preferred, using successively a suboccipital and an intradural subtemporal route, the latted giving access to the cavernous sinus in case of its invasion.     

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.     

Computed tomography-guided stereotactic aspiration of posterior fossa hematomas: a supine lateral retromastoid approach

We report a supine lateral retromastoid approach for computed tomography-guided stereotactic aspiration of hematomas of the posterior fossa. The method involves horizontal insertion of the aspiration needle at the suboccipital region with the patient in a supine position with the head turned 30 to 40 degrees away from the lesion and with slight forward flexion of the neck. Eleven hematomas have been removed through this approach thus far, nine cerebellar and two pontine. With this technique, general anesthesia is not needed and operative invasion is minimal, allowing hematoma aspiration in patients in whom operation would previously not have been indicated. An additional merit is the suitability of this method for elderly patients.