远外侧枕下入路临床应用的初步经验

目的 改良远外侧枕下入路,适当显露病变,改善延髓和上颈髓腹侧病变的治疗效果。方法 采用远外侧枕下入路的5种改良入路,包括经小关节入路、经枕骨髁后入路、部分经枕骨髁入路、完全经枕骨髁入路和极端外侧经颈静脉孔入路,治疗延髓及上颈髓腹侧和腹外侧肿瘤12例、椎动脉动脉瘤2例,并分析手术治疗的效果和并发症。结果 本组12例肿瘤患者,7例肿瘤全切除,5例肿瘤在部分切除,所有患者术后恢复良好;其中3例术后遗留永久性组颅神经麻痹。2例动脉瘤患者,1例夹闭瘤颈,1例动脉瘤切除的患者因脑干缺血死亡。没有与入路有关的严重并发症。结论 远外侧枕下入路的改良可以满足延髓及上颈髓腹侧和腹外侧病变手术的需要和良好手术野显著,减少不必要的手术步骤,改善治疗效果。     

远外侧入路显微手术治疗枕大孔区延髓及颈髓腹侧肿瘤

目的 探讨远外侧入路显微手术切除枕大孔区延髓及颈髓腹侧肿瘤的临床疗效.方法 18例延髓及颈髓腹侧肿瘤均采用远外侧入路,咬除病变侧C1后弓、枕鳞及枕大孔后外缘,保护椎动脉,显露延髓及颈髓的侧方,在手术显微镜下行显微手术治疗.结果 18例中全部切除肿瘤13例(72.2%),次全切除4例(22.2%),未能切除1例(5.6%),术后症状消失11例,症状改善6例,无改善1例.结论 经远外侧入路治疗枕大孔区延髓及颈髓腹侧肿瘤临床效果良好.     

不同解剖入路显露颈静脉孔区的定量研究

目的定量研究枕下远外侧入路及耳后经颞入路对颈静脉孔区的显露程度,为临床个体化选择手术入路、保护重要结构功能提供可靠的解剖依据。方法选择经10％福尔马林固定的成人头颈湿标本各12具（24侧）,采用枕下远外侧入路及耳后经颞入路进行解剖学研究,用脑立体定向仪测定各步骤颈静脉孔区的显露面积,用游标卡尺测量斜坡和三叉神经的显露长度。结果在远外侧入路中,磨除颈静脉突、部分磨除枕髁后对颈静脉孔区显露程度显著增加;在耳后经颞入路中,迷路后入路、部分磨除迷路对颈静脉孔区的显露程度显著增加。结论磨除颈静脉突是枕下远外侧入路显露颈静脉孔的关键;迷路下入路和部分磨除迷路入路是自侧方显露颈静脉孔区的理想手术入路。     

枕下远外侧经髁入路显微手术切除延髓腹外侧区肿瘤

枕下远外侧经髁入路显微手术切除延髓腹外侧区肿瘤杨卫忠，石松生，张国良，刘才兴，倪天瑞，梁日生，陈建屏延髓腹外侧区的部位深在，且重要结构众多，以致致该区域病变的手术治疗一直是神经外科的难题。９０年代以来，我们采用枕下远外侧经髁入路显微手术治疗延髓腹外侧...     

后外侧枕下入路手术治疗枕大孔前方和下斜坡病变

作者报告一种治疗下脑干和上颈髓腹侧病变的手术入路。它包括枕下瓣状切口形成一侧皮瓣，暴露和切除枕下骨质、颈、半椎板以及酌情切除枕骨髁和颈１外侧块。将椎动脉暴露于术野。采用此手术入路，无手术死亡和与手术入路有关的并发症发生。     

枕大孔区脑膜瘤的显微手术治疗

目的报道枕大孔区脑膜瘤的显微神经外科手术的临床结果。方法选择经枕大孔后缘入路包括枕髁远外侧入路、枕下后正中入路和枕下下外侧入路，应用显微外科手术治疗的枕大孔区脑膜瘤7例，并结合文献分析影响枕大孔区脑膜瘤的手术入路的选择和影响预后的因素。结果肿瘤最大直径为0．8～4．8cm，肿瘤瘤体位置位于脑干前方3例，侧方2例，后方2例。经枕髁远外侧入路2例，枕下后正中入路3例，枕下外侧入路2例，肿瘤手术全切除6例（Simpson Ⅰ级4例，Simpson Ⅱ级2例），次全切除1例。术后6例随访6～36个月，神经系统占位症状较术前明显好转，未见肿瘤残留和复发。结论选择合适的经枕大孔后缘的手术入路，应用显微外科手术治疗枕大孔区脑膜瘤可获得较好的临床效果。     

远外侧入路显微切除斜坡和枕大孔区腹侧肿瘤

目的 探讨斜坡、枕大孔区腹侧病变的手术方法和远外侧入路手术适应证。 方法 选择斜坡和枕大孔区腹侧病变２２例,其中脊索瘤１０例,脑膜瘤４例,舌下神经鞘瘤４例,椎－基底动脉汇合处动脉瘤２例,软骨肉瘤和纤维肉瘤各１例。３例肿瘤下极达颈２水平。依据需要磨除枕骨髁１／３或全部及其它骨块。２例侵入咽后壁的脊索瘤先经远外侧入路切除颅内部分肿瘤,再二期经口咽入路切除咽后壁部分。 结果 显微手术全切除１８例,次全切     

远外侧入路切除颅颈区肿瘤

目的：介绍颅颈交界处肿瘤切除的经验,探讨远外侧入路的选择及显微手术技巧。方法：对23例患者采用远外侧入路,在显微镜直视下切除肿瘤。结果：肿瘤全部切除17例,近全切除4例,大部切除2例,全切除率74％,无死亡,结论：远外侧入路可以非常直接地显露下斜坡,易于控制动,对脑神经及颅颈交界处提供良好暴露,最小程度牵拉神经血管结构,使手术更加安全和成功。     

枕骨大孔区脑膜瘤的显微外科治疗

目的探讨枕骨大孔区脑膜瘤的治疗方法以提高治疗效果。方法总结自1995午6月～2004年2月通过显微外科手术治疗18例枕骨大孔区脑膜瘤的经验。采用3种手术入路切除肿瘤：枕颈后正中或侧方入路10例。远外侧或经髁入路7例，枕下乙状窦后入路1例。结果肿瘤全切除14例，次全切除3例，部分切除1例，无手术死亡。结论合理选择手术入路能提高肿瘤全切除率及颅神经的保护，远外侧经髁入路是有效的手术入路。     

后颅窝远外侧入路的应用解剖学研究

目的：为后颅窝远外侧入路的临床应用提供解剖学基础。方法：模拟该入路对３０例（６０侧）国人成年带颈头颅标本，在手术显微镜下进行了解剖和测量。结果：处理阻碍术野的乙状窦（ＳＳ）、椎动脉（ＶＡ）、寰枕关节（ＡＯＪ）是关键步骤；结果：ＳＳ横、纵径均约１０ｍｍ，枕髁长约２３ｍｍ，舌下神经管内口处枕髁深厚约７ｍｍ，该内口至ＡＯＪ后缘约１２ｍｍ。结论：马蹄形皮切口、向后下方牵移ＶＡ、结扎切断ＳＳ、磨除枕髁后１／３（厚度小于７ｍｍ）及依病变位置采用不同操作间隙较为安全而实用。     

The extreme lateral transcondylar approach to aneurysms of the vertebrobasilar junction, the vertebral artery, and the posterior inferior cerebellar artery

The unilateral suboccipital craniotomy is the commonly performed approach to aneurysms of the vertebrobasilar junction, the vertebral artery, and the posterior inferior cerebellar artery (PICA). Many of these aneurysms are placed anterior or anterolateral to the brain stem, necessitating brain stem retraction for adequate exposure. Small dorsolateral enlargement of the foramen magnum, partial resection of the occipital condyle, and removal of the jugular tubercle allow access to the neurovascular structures ventral to the medulla without retraction of the neuroaxis. This extreme lateral transcondylar approach was performed in 20 patients with aneurysms of the vertebrobasilar junction, the vertebral artery, and the PICA; intraoperatively, two suspected aneurysms proved to be vascular malformations. Occlusion of the aneurysm and vascular malformation was successfully performed in 16 patients, resection of the vascular malformation was achieved in 1 patient, and the vertebral artery was clipped in 3 patients with fusiform aneurysms without complications related to the extreme lateral transcondylar approach. Unobstructed exposure of the aneurysm, parent artery, and neural structures without retraction of the sensitive lower brain stem are the major advantages of the extreme lateral transcondylar approach.     

The Extreme Lateral Transcondylar Approach to Aneurysms of the Vertebrobasilar Junction, the Vertebral Artery, and the Posterior Inferior Cerebellar Artery

The unilateral suboccipital craniotomy is the commonly performed approach to aneurysms of the vertebrobasilar junction, the vertebral artery, and the posterior inferior cerebellar artery (PICA). Many of these aneurysms are placed anterior or anterolateral to the brain stem, necessitating brain stem retraction for adequate exposure. Small dorsolateral enlargement of the foramen magnum, partial resection of the occipital condyle, and removal of the jugular tubercle allow access to the neurovascular structures ventral to the medulla without retraction of the neuroaxis. This extreme lateral transcondylar approach was performed in 20 patients with aneurysms of the vertebrobasilar junction, the vertebral artery, and the PICA; intraoperatively, two suspected aneurysms proved to be vascular malformations. Occlusion of the aneurysm and vascular malformation was successfully performed in 16 patients, resection of the vascular malformation was achieved in 1 patient, and the vertebral artery was clipped in 3 patients with fusiform aneurysms without complications related to the extreme lateral transcondylar approach. Unobstructed exposure of the aneurysm, parent artery, and neural structures without retraction of the sensitive lower brain stem are the major advantages of the extreme lateral transcondylar approach.     

Microsurgical Excision of the Craniocervical Neurenteric Cysts by the Far-Lateral Transcondylar Approach: Case Report and Review of the Literature

Neurenteric cysts in the anterior craniocervical junction (CCJ) region can be found in extremely rare cases. We report one case with craniocervical neurenteric cyst that was excised by the far-lateral transcondylar (FLT) approach. A 43-year-old man presented with a history of recurrent episodes of mild neck pain and dysesthesia in his bilateral hands of 2 years'' duration with rapid deterioration 3 weeks prior to admission. Magnetic resonance imaging (MRI) of the CCJ region revealed a well-defined intradural cystic lesion located ventral from the pontomedullary junction to C1 vertebra with medulla and C1 cord compression. This patient underwent total excision of the lesion via the FLT approach without any postoperative neurological deficits, and the histopathologic diagnosis was neurenteric cyst. Follow-up MRI has revealed no evidence of recurrence. The clinical features, imaging studies, and surgical approach options involved in resecting craniocervical neurenteric cysts are discussed, along with a review of the literature.     

Quantitative description of the far-lateral transcondylar transtubercular approach to the foramen magnum and clivus

OBJECT: The purpose of this study was to evaluate the far-lateral transcondylar transtubercular approach (complete FLA) based on quantitative measurements of the exposure of the foramen magnum and petroclival area obtained after each successive step of this approach. METHODS: The complete FLA was reproduced in eight specially prepared cadaveric heads (a total of 15 sides). The approach was divided into six steps: 1) C-1 hemilaminectomy and suboccipital craniectomy with unroofing of the sigmoid sinus (basic FLA); 2) partial resection of the occipital condyle (up to the hypoglossal canal); 3) removal of the jugular tuberculum; 4) mastoidectomy (limited to the labyrinth and the fallopian canal) and retraction of the sigmoid sinus; 5) resection of the lateral mass of C-1 with mobilization of the vertebral artery; and 6) resection of the remaining portion of the occipital condyle. After each successive step, a standard set of measurements was obtained using a frameless stereotactic device. The measurements were used to estimate two parameters: the size of the exposed petroclival area and the size of a spatial cone directed toward the anterior rim of the foramen magnum, which depicts the amount of surgical freedom available for manipulation of instruments. The initial basic FLA provided exposure of only 21 +/- 6% of the petroclival area that was exposed with the full, six-step maximally aggressive (complete) FLA. Likewise, only 18 +/- 9% of the final surgical freedom was obtained after the basic FLA was performed. Each subsequent step of the approach increased both petroclival exposure and surgical freedom. The most dramatic increase in petroclival exposure was noted after removal of the jugular tuberculum (71 +/- 12% of final exposure), whereas the least improvement in exposure occurred after the final step, which consisted of total condyle resection. CONCLUSIONS: The complete FLA provides wide and sufficient exposure of the foramen magnum and lower to middle clivus. The complete FLA consists of several steps, each of which contributes to increasing petroclival exposure and surgical freedom. However, the FLA may be limited to the less aggressive steps, while still achieving significant exposure and surgical freedom. The choice of complete or basic FLA thus depends on the underlying pathological condition and the degree of exposure required for effective surgical treatment.     

Transcondylar fossa approach to treat ventral foramen magnum meningioma--case report

A 41-year-old female presented with a meningioma of the craniocervical junction manifesting as tetraparesis and vesicourethral dysfunction. Neuroradiological examinations showed a homogeneous enhanced mass lesion extending from the foramen magnum to the upper aspect of the second vertebral body. The tumor was totally removed via the transcondylar fossa approach, which is one type of the lateral approach. She was discharged without neurological deficits. The transcondylar approach is often utilized for lesions that occupy the ventral portion around the foramen magnum. The transcondylar fossa approach, a variation of the transcondylar approach, is a refined technique which obtains a closely similar surgical working field. Use of the transcondylar fossa approach remains controversial when treating patients with little brain stem dislocation, a small condylar fossa, and a protruding occipital condyle, but the approach can easily be converted to the transcondylar approach. The transcondylar fossa approach could become a standard method to access the craniocervical junction.     

Endoscopic far-lateral approach to the posterolateral craniovertebral junction: an anatomical study

Minimally invasive surgery to the posterolateral craniovertebral junction (CVJ) has not been sufficiently described. The aims of this study were to evaluate the feasibility of an endoscopic far-lateral approach to the posterolateral craniocervical junction and to better understand the related anatomy under distorted endoscopic view. Ten fresh cadavers were studied with 4-mm 0° and 30° endoscopes to develop the surgical approach and to identify surgical landmarks. After making a 3-cm straight incision behind the mastoid process, the superior oblique and rectus capitis posterior major muscles were partially exposed. An endoscope was then introduced and the two muscles were followed inferiorly until the posterior arch of the atlas appeared. The two muscles were removed to create ample working space without violating the posterior atlanto-occipital membrane. The vertebral artery was identified by the landmark of the posterior arch of the atlas, and the atlanto-occipital joint and foramen magnum were exposed. In addition to suboccipital craniectomy, transcondylar, supracondylar, and paracondylar extension by drilling were applicable through the narrow corridor under superb visualization. The intradural neurovascular structures from the acousticofacial bundle to the dorsal root of C2, anterolateral space of the foramen magnum, cerebellomedullary fissure, and fourth ventricle were clearly demonstrated. This endoscopic far-lateral approach offers excellent exposure of surgical landmarks around the posterolateral CVJ with minimal invasiveness. Endoscopic soft tissue dissection is key to creating the surgical corridor. This approach could offer an alternative to the conventional far-lateral approach in selected cases.     

The transoral approach to the superior cervical spine. A review of 53 cases of extradural cervicomedullary compression

The transoral-transclival surgical approach is the most direct operative approach to pathology ventral to the brain stem and superior spinal cord. In selected patients, this approach is efficacious in the treatment of extradural compressive lesions from the cervicomedullary junction to the C-4 vertebra. The authors have used the transoral surgical approach in treating 53 patients with lesions compressing the ventral extradural brain stem or the cervical cord. The evaluation, management, and long-term outcome of these patients are described (median follow-up time 24 months). The operative morbidity rate in this series was 6%, and the operative mortality rate was zero. The authors review specific features of the transoral procedure, including methods of retraction, microsurgical techniques, and adjunctive measures to avoid cerebrospinal fluid fistulae, that contributed to these good results.     

The dorsolateral, suboccipital, transcondylar approach to the lower clivus and anterior portion of the craniocervical junction.

The authors review their experience with a dorsolateral approach to the anterior rim of the foramen magnum and adjacent region. The operative technique includes exposure of the vertebral artery at C1, partial resection of the occipital condyle and lateral atlantal mass, and extradural drilling of the jugular tubercle. This approach has been applied in six patients who harbored intradural space-occupying lesions located ventral to the lower brain stem. Excision of the neoplasm was virtually total in all but one patient, in whom biopsy was the primary goal of the intervention. No morbidity and no mortality were associated with this approach. The main advantage of the dorsolateral, suboccipital, transcondylar route is the direct view it offers to the anterior rim of the foramen magnum without requiring brain stem retraction.     

Surgical approaches for vertebro-basilar trunk aneurysms located in the midline

Summary Fourteen cases of midline vertebro-basilar trunk aneurysms were operated on by four routes of surgical approach: middle fossa anterior transpetrosal approach (ATP), presigmoid transpetrosal approach (PTP), conventional lateral suboccipital approach (LSO) or suboccipital transcondylar approach (STC). There was no mortality, but the morbitity was different depending on the surgical approach. In basilar trunk aneurysms located higher than the internal auditory canal, excellent results were obtainable by ATP, especially in the case of posteriorly projecting aneurysms. For midline vertebral aneurysms located lower than the internal auditory canal, STC resulted in less surgical complications than LSO. Extradural resection of the jugular tubercle was necessary for aneurysms located on the distal vertebral artery at or close to the vertebro-basilar junction. For vertebro-basilar junction aneurysms located at the level of the internal auditory canal, hearing was preserved by STC, but not by ATP or PTP. However, choice of the surgical approach may depend on the direction of the aneurysm and the technical accessibility of the skull base. All these skull base approaches reduced surgical complications of retraction damage to the cranial nerves and the brain stem. This holds true for all aneurysms arising from the midline vertebro-basilar trunk.