乙状窦前经迷路锁孔入路的显微解剖

目的将微创锁孔理念融入乙状窦前入路，在神经导航辅助下，设计乙状窦前经迷路锁孔入路，观察入路显微解剖，为临床应用提供依据。方法采用8具经福尔马林固定、颅内动静脉乳胶灌注的国人成人尸头，实验前建立术中导航资料。采用迷路后锁孔手术入路的7cm“C”形切口，分层向前翻开皮瓣和肌筋膜瓣，在神经导航辅助下做耳后约3．5cm×3．0cm骨窗，导航下轮廓化乙状窦、骨迷路、面神经管，依次模拟迷路后、经部分迷路及岩尖、经全迷路锁孔入路，观察各步骤显露的结构，测量重要结构长度和术野角度。结果（1）神经导航可辅助精确磨除入路相关骨质，减少盲目磨除造成的重要结构的误伤。（2）同迷路后锁孔入路比较，经部分迷路及岩尖锁孔入路和经全迷路锁孔入路的术野角度、显露的斜坡长度、面神经颅内段长度均有显著增加，但后两种入路的测量值无明显差异。（3）迷路后锁孔入路可保留听力和面神经功能，但对岩斜区的显露有限；部分迷路及岩尖磨除后可广泛显露岩斜区、桥脑小脑角、桥脑前区和海绵窦后部，多角度显露Ⅲ-Ⅺ对脑神经之间的重要结构，且面、听神经功能保有率极高；全迷路磨除后观察角度更多，但进一步增加的显露有限，且需牺牲听力。结论乙状窦前经迷路锁孔入路具有可行性，可良好显露岩斜区等。神经导航可辅助精确完成入路相关的骨质磨除。部分迷路及岩尖或全迷路磨除均可显著增加术野角度和斜坡等重要结构的显露长度，经部分迷路及岩尖锁孔入路可望保留面、听神经功能。     

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。     

远外侧枕骨髁上锁孔入路的显微解剖

目的在枕骨髁后锁孔入路基础上,探索磨除颈静脉结节的可行性,形成枕骨髁上锁孔入路,探讨其适应证,为临床应用提供解剖学基础。方法10%甲醛固定、颅内动静脉乳胶灌注的成人尸头8具,采用枕骨髁后锁孔入路的“S”形7cm切口,逐层游离、翻转肌肉,做枕骨髁后直径约3cm骨窗,在导航辅助下于硬膜外磨除颈静脉结节,观察显露的解剖结构并测量其长度。结果乳突中点向后2cm处至C_2水平的纵向“S”形7cm长头皮切口可充分暴露同侧颈静脉结节、寰枕关节椎动脉V3段及寰椎后弓,磨除颈静脉结节效果满意,可显露基底动脉下段、小脑前下动脉等桥延沟附近中斜坡结构；显露基底动脉的长度(15．65±1．34)mm,小脑前下动脉(20．36±4．18)mm。结论远外侧枕骨髁上锁孔入路具有可行性；磨除颈静脉结节可增加中斜坡的显露,适合椎-基系动脉瘤、小脑前下动脉瘤、累及中斜坡的延髓腹侧肿瘤以及颈静脉孔区肿瘤等手术。     

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。     

远外侧入路治疗颅颈交界腹侧病变的探讨

目的 探讨远外侧人路在处治中下斜坡、颈延交界区腹侧及颈静脉孔区病变的应用。方法对23例患者采用远外侧入路显微外科手术,其中枕髁后入路12例,经部分枕髁入路5例,经C1-2关节面侧方联合经部分枕髁入路3例,经颈静脉结节入路2例,经完整枕髁入路1例。结果20例肿瘤全部切除15例,近全部切除5例,3例椎一基底动脉瘤均顺利夹闭,3例行枕颈融合,无手术死亡率,结果满意。所有患者术后均未出现寰枕关节不稳定的症状,手术并发症主要是后组颅神经损伤、椎动脉损伤、脑脊液漏以及脑干、小脑或脊髓缺血。结论远外侧入路是脑干和上段颈髓腹侧、腹外侧病变的理想入路,但手术操作较复杂,具有一定的潜在风险,应根据病变性质、位置和延伸范围来选择入路,进而最低限度切除颅底骨质。     

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.     

神经导航辅助下远外侧锁孔入路显露岩斜区的量化研究

目的量化研究磨除部分枕髁和颈静脉结节在远外侧锁孔入路中的作用和意义。方法在导航辅助下，对6具尸头标本（12侧）顺次模拟枕髁后、经髁和枕髁上锁孔入路，分别测量术野显露角度、斜坡显露面积和手术操作自由度。结果磨髁前、磨髁1／3和1／2的术野显露角度分别为：（39．20±3．29）°、（51．46±2．45）°和（57．52±2．66）°；斜坡显露面积和手术操作自由度分别为（188．1±32．5）mm^2和（340．2±112．6）mm^2（枕髁后锁孔）、（208．5±28．4）mm^2和（654．6±154．7）mm^2（磨髁1／3）、（236．4±30．2）mm^2和（762．1±182．4）mm^2（磨髁1／2）、（428．6±28．7）mm^2和（983．4±235．2）mm^2（磨除颈静脉结节）；磨除1／3、1／2枕髁的术野显露角度均与磨除前差异有统计学意义（P〈0．01），且磨除1／2枕髁与1／3相比差异亦有统计学意义（P〈0．01）；磨除颈静脉结节可显著增加斜坡显露面积（P〈0．01），而磨除1／3、1／2枕髁和颈静脉结节均能显著增加手术操作自由度（P〈0．05）。结论磨除部分枕髁可显著增加术野显露角度和手术操作自由度，磨除颈静脉结节可使手术操作自由度和斜坡显露面积都显著增加。     

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。     

远外侧枕下入路切除高颈段椎管内外哑铃形肿瘤(附4例报告)

目的 :探讨经远外侧枕下入路切除高颈段椎管内外哑铃形肿瘤的治疗效果及手术技巧。方法 :回顾分析 4例经远外侧枕下入路切除高颈段椎管内外哑铃形肿瘤病人的临床资料及手术治疗结果。结果 :肿瘤全切 3例 ,1例因肿瘤包绕椎动脉而次全切除。所有患者术后恢复良好 ,未出现与手术入路有关的严重并发症。结论 :远外侧枕下入路具有手术路径短、视野宽广、显露硬膜内外病变清楚等优点 ,是治疗高颈段椎管内外哑铃形肿瘤的一种实用手术入路     

改良部分迷路切除岩骨尖入路的显微解剖

目的应用锁孔理念,对部分迷路切除岩骨尖入路进行改良,并对改良后的入路进行显微解剖学研究。方法对15例30侧成人尸头采用改良部分迷路切除岩骨尖入路暴露岩斜区,测量磨除部分迷路和岩骨尖后增加的手术视野和视角,观察岩斜区解剖结构的暴露情况。结果在4cm×3cm大小的骨窗范围内可以完成所有的手术操作。磨除部分迷路和岩骨尖后,手术水平视野平均增加14·2mm,垂直视野平均增加12·5mm,手术水平视角平均增加58°,垂直视角平均增加46°,该入路可充分暴露岩斜区各解剖结构,与原入路相比无明显差别。结论改良部分迷路切除岩骨尖入路暴露充分,较原入路创伤小,脑牵拉轻,不容易损伤颈静脉球和面神经颅外段等重要结构,是一种良好的处理岩斜区病变的手术入路。     

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.     

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.     

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.     

The supracondylar approach to the jugular tubercle and hypoglossal canal

Background Circumscribed lesions of the hypoglossal canal and of the jugular tubercle still remain a surgical challenge. So far, transpetrosal, transcondylar suboccipital, and extreme lateral approaches have been used to access this region. These surgical procedures bear a high risk for neurological deficits. Therefore, we introduce a new minimally invasive extradural approach to the hypoglossal canal that also allows access to the lateral aspects of the jugular tubercle.

Methods After a paramedian retromastoid skin incision, a basal suboccipital craniectomy lateral to the foramen magnum toward the jugular tubercle is performed. With this approach the occipital condyle and the lateral osseous circumference of the foramen magnum are preserved. Drilling extradurally, the dorsal parts of the jugular tubercle are removed. The exposure is extended downward to the posterior margins of the hypoglossal canal and laterally to the jugular bulb, enabling a minimally invasive exposure of the hypoglossal canal, the lateral aspects of the jugular tubercle, and medial aspects of the jugular bulb.

Results Using this supracondylar approach, surgical interventions were performed in three patients suffering from a hypoglossal neurinoma, a cholesterol granuloma extending into the jugular tubercle, and a cyst of the hypoglossal canal, respectively. No additional postoperative neurological deficits were seen.

Conclusions The supracondylar approach seems to be useful to gain access to benign lesions of the hypoglossal canal and of the jugular tubercle to decompress tumors or cysts. In contrast to previously reported techniques this approach has a low risk of morbidity. The surgical field, however, is restricted laterally by the jugular bulb, medially and basally by the residual occipital condyle and dorsally by the dura. Therefore, this approach is useful to remove small lesions or to perform extended biopsies. Radical removal of large tumors seems to be problematic using this approach.     

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.     

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 effect of condylectomy on extreme lateral transcondylar approach to the anterior foramen magnum

Summary The dorsolateral, suboccipital, transcondylar technique was used in this cadaveric study. The angle and distance measurements in the corridors were taken intradurally both superior and inferior of the foramen magnum level. In the first stage of this study, the findings which were gained from the standard lateral suboccipital approach were compared with the findings after condyle and lateral atlantal mass removal. After condylectomy, the approach to anterior foramen magnum via both corridors was found to be shorter and the lateral angle of the exposure of the anterior foramen magnum was found to be wider. The considerable shortening of the distances to the anterior foramen magnum, especially in the superior corridor, emphasises the necessity of combining standard approaches with condylectomy. In addition, it was found that after condylectomy, considerable widening of both transverse and longitudinal planes in the inferior corridor allows the surgeon greater access to work on lesions. Furthermore, the freed space between the superior corridor and the inferior corridor, which was gained by condylectomy, shows that condylectomy provides a combined approach to the inferior and superior parts of the foramen magnum anteriorly.     

联合上颈段经颈静脉孔区入路的显微解剖学研究

目的 研究颈静脉孔区(JF)入路的显微解剖,利用该入路一期切除颅内外沟通型复杂病变.方法 成人尸头标本15例(30侧),在手术显微镜下进行联合上颈段经JF区入路的解剖操作,测量相关数据.结果 对C1～C4上颈段解剖,切除C1横突,游离椎动脉C1～C2段及水平段;充分切除颈静脉结节、颈静脉突及部分枕骨髁;迷路后切除乳突,显露半规管,轮廓化面神经垂直段,全程暴露乙状窦,打开颈静脉孔;扩大了JF区的显露并测得相关参数,如乳突尖间距枕髁外缘中点为(29.65±3.24)mm;枕髁后缘距舌下神经管内口为(10.10±0.81)mm;颈静脉球距面神经垂直段间距左为(6.8±0.35)mm,右为(4.6±0.33)mm.结论 此入路从多个方向对JF区充分暴露,使面神经、耳蜗、椎动脉、后组脑神经等结构得到保护,术中结合相关解剖参数可很好的完成一期全切JF区颅内外沟通型及延伸到上颈位的病变,提高治愈率、减少并发症、降低死亡率.     

Subtonsillar approach to the foramen of Luschka: an anatomic and clinical study

OBJECTIVE: Conventional approaches to tumors of the foramen of Luschka are limited because the foramen is viewed from either the fourth ventricle laterally (transvermian approach) or the cerebellopontine angle medially (suboccipital approach). The definitive approach is subtonsillar, because the foramen of Luschka is actually the end of the natural cleavage plane between the cerebellar tonsil and the medulla. We describe the microsurgical anatomic features of the foramen of Luschka region and the operative technique for the subtonsillar approach to this region. METHODS: In the anatomic study, five formalin-fixed, silicone-injected, cadaveric heads were used. In the clinical study, the records for five patients treated via the subtonsillar approach were examined; several illustrative cases are presented. RESULTS: The foramen of Luschka is formed by the tela choroidea and the rhomboid lip and exists at the lateral end of the cerebellomedullary fissure, which is a natural cleavage plane between the cerebellar tonsil and the medulla. The subtonsillar approach is performed via a suboccipital craniotomy; the patient is positioned in the lateral decubitus position, with the tumor side down. After the cerebellar tonsil is freed from arachnoid adhesions, it can be retracted rostrodorsally from the medulla, to expose the cerebellomedullary fissure. Clinically, the tela choroidea and rhomboid lip are significantly attenuated by tumor expansion. Therefore, by dissecting in a subtonsillar manner around the tumor, one can reach the foramen of Luschka without traversing any neural tissue. CONCLUSION: The subtonsillar approach yields a panoramic view to the foramen of Luschka laterally and up to the middle cerebellar peduncle superiorly. This approach minimizes the distance between the tumor and the surgeon, while maximizing neural preservation. We think this is the definitive approach to this difficult region of the posterior fossa.