枕髁形态学分类对下斜坡病变的手术意义

目的通过对国人颅骨的枕髁和枕大孔进行解剖测量和分析，提出枕髁的形态学分类方法，为枕下外侧入路处理下斜坡和枕大孔腹侧病变的手术中，是否需要磨除枕髁提供解剖学依据。方法在100例成人颅骨标本和20例成人3D—CT上，测量枕大孔和枕髁的相关解剖数据，观察分析两者的相对位置关系，按枕髁分类指数（OCindex）进行分类，并对各类枕髁（组）磨除后部1／3，前、后的手术观察角度进行统计学对比分析。结果100例成人颅骨标本分为Ⅰ型（小枕髁型8．0％），Ⅱ型（中枕髁型74％），Ⅲ型（大枕髁型18％）。Ⅰ型中磨除枕髁后部1／3，前后观察角度无统计学意义（P〉0．05），但在Ⅱ型（P〈0．05）和Ⅲ型中有统计学意义（P〈0．01）。结论枕髁的形态学变异较大。术前应用3D—CT明确枕髁的形态学类型，对手术中是否需要磨除枕髁具有指导意义。     

The anatomic study of clival screw fixation for the craniovertebral region

Purpose

To study the anatomic parameters related to clival screw and establish reference data concerning the craniovertebral fixation technique.

Methods

Morphometric measurement of the clivus and the surrounding anatomic structures were obtained on 41 dry bone specimens. Then, 2-D CT reconstruction of the craniovertebral region of 30 patients (19 men and 11 women, ranging in age from 20–64 years with an average age of 38.8 years) were performed to measure the safety range for a 3.5-mm screw placement. Nine entry points were evaluated. Finally, one male fresh cadaver specimen (age 46 years) was dissected to observe the craniovertebral region.

Results

The clivus faces the basilar artery, the V ~ XII cranial nerves, the pons, and ventral medulla oblongata at its intracranial surface. The longitudinal diameter of extracranial clivus was 25.87 ± 2.64 mm. The narrowest diameter of the clivus was 12.84 ± 1.08 mm, the distance between the left and right hypoglossal canal was 32.70 ± 2.09 mm at its widest part. The distance between the left and right structures, the maximum value was 49.31 ± 4.16 mm at carotid canal, the minimum value was 16.54 ± 2.04 mm at the occipital condyle. The measurement of clival screws placement simulation via 2-D CT reconstruction images shows the maximum upper insertion angle of three components the optimal entry points, the candidate points, the limit entry points was 130.19°, 125.23° and 85.72°, and the total mean screw length was 7.57, 10.13 and 15.6 mm at the vertical entry angle, respectively.

Conclusions

Clival screw placement is a viable option for craniovertebral fixation. There is a safe scope for the screw length and angle of the screw placement. And, these parameters obtained in the present study will be helpful for anyone contemplating the use of clival screw fixation.     

The extended endoscopic endonasal approach to the clivus and cranio-vertebral junction: anatomical study

Object Lesions located in the retroclival area and at the level of the cranio-vertebral junction are typically approached through a variety of anterior, antero-lateral and postero-lateral skull-based approach, either alone or in combination. The aim of this anatomical study was to demonstrate the possibility of an endoscopic endonasal approach to the clivus and cranio-vertebral junction. Materials and methods Five fresh cadaver heads injected with colored latex were used. A modified endonasal endoscopic approach was made through two nostrils in all cases. Endoscopic dissections were performed using rigid endoscopes, 4 mm in diameter, 18 cm in length, with 0° lenses. Results Access to the clivus was possible using a lower trajectory when compared to that necessary for the sellar region. The sphenoid sinus is entered, and its inferior wall is completely removed, permitting the union of the sphenoidal and rhinopharyngeal parts of the clivus. The entire clivus can be removed, and the cranio-vertebral junction is opened, removing the anterior arch of atlas and the odontoid process. After the opening of the dura, the anterior surface of the pons and upper spinal cord with corresponding nerves and vasculature are visible. Conclusion The endoscopic endonasal approach to the clivus and cranio-vertebral junction could be a valid alternative for surgical treatment of anterior lesions of these regions. Adequate endoscopic skill, lab training on cadavers and dedicated tools are required for clinical applications of the approach. Presented at the Third World Conference of the International Study Group on Neuroendoscopy (ISGNE), Marburg, Germany, 15–18 June 2005.     

内镜辅助经鼻蝶入路至斜坡区的显微手术

目的 探讨内镜辅助经鼻蝶入路至斜坡区的显微手术方法和疗效.方法 根据经鼻蝶入路至鞍区斜坡区显微解剖学研究结果,采用内镜辅助经鼻蝶显微手术治疗该区肿瘤12例(侵袭性垂体腺瘤8例,脊索瘤3例,软骨瘤1例).所有病例均在3个月至6年内获得随访.结果 手术全切8例,次全切除3例,部分切除1例.术后发生短暂性尿崩症6例,脑脊液鼻漏2例,无死亡及颅内感染.随访3个月至6年,除1例脊索瘤残瘤继续生长外,其余患者未见肿瘤复发.结论 采用经蝶入路显微手术切除沿中线生长的鞍区斜坡区肿瘤,入路简便快捷,创伤小,手术显露良好,疗效满意.内镜辅助使得经蝶入路更为安全、有效.     

The retrosigmoid approach to petroclival meningioma surgery

Petroclival meningiomas are technically challenging lesions. The authors retrospectively analyzed their experience between 2000 and 2010 in 82 patients with petroclival meningioma to evaluate changes in management strategy. A total of 42 patients (51%) were treated via the retrosigmoid approach. The patients received postoperative neurological and neuroradiological follow-up. The maximum diameter of the tumors ranged from 1.5 cm to 6.5 cm (mean, 3.8 cm). Gross total resection (Simpson Grade II) was achieved in 27 patients (64%), subtotal resection (Simpson Grade III) in 11 (26%), and partial removal (Simpson Grade IV) in four (9.5%). Ten patients (24%) had new neurological deficits or worsening of pre-existing deficits. One patient (2%) died because of brainstem dysfunction after surgery. The retrosigmoid approach is suitable for treatment of selected petroclival meningioma if the main part of the tumor is located in the posterior fossa in the cerebellopontine angle and the low clivus, and only a minor part of the tumor extends to the posterior wall of the cavernous sinus. This approach provides a low degree of surgical difficulty and a low complication rate.     

扩大前颅底入路显露斜坡中央凹陷区的量化研究

目的量化研究扩大前颅底入路中每一步骤骨切除后所获得斜坡中央凹陷区显露范围及手术自由度变化，为其临床应用提供客观依据。方法10％甲醛溶液同定的头颅标本20例，在CT辅助下利用立体定向仪在头颅标本上标记斜坡中央凹陷区中心点。采用扩大前颅底入路，骨切除分四步进行：单纯额下蝶窦斜坡，额下蝶筛窦斜坡，扩大额下蝶筛窦斜坡，扩大截眶、视神经管内侧壁磨除。每一步完成后分别测量斜坡中央凹陷区的显露范围和位于斜坡中央凹陷区中心点上方15cm处术者操作空间的面积。结果随着骨切除范围的增加，斜坡中央凹陷区的显露范围和手术自由度逐渐增加，最显著的变化发生在扩大额下蝶筛窦斜坡完成后，所获得的显露范围为（210±18）mm^2，占整个入路完成后的（96±1）％，所获得的手术自由度为（4035±376）mm^2，占整个入路完成后的（91±8）％。结论扩大前颅底入路在完成扩大额下蝶筛窦斜坡后即能较好的显露斜坡中央凹陷区，并能提供足够的手术自由度，主要适用于硬膜外颅底中线部位肿瘤的切除。     

Osteosarcoma of the skull base: case report and review of literature

Osteosarcoma is the most common primary malignancy of bone in children and adolescents. Osteosarcomas are an aggressive neoplasm composed of spindle cells producing osteoid. They primarily affect the long bones, particularly after radiation or chemotherapy for other neoplasms; however, 6-7% present in the head and neck. Primary head and neck osteosarcomas in children are rare. There are few case reports and limited-sized case series in the literature. A case report presentation of a skull base osteosarcoma in a teenage female. A 14-year-old African American female presented with dysphagia, voice changes, and neck pain. On examination, she had right-sided palsies in cranial nerves X, XI, and XII. Imaging revealed partial enhancement of the clivus without bony erosion and expansion of the hypoglossal canal. There were also findings consistent with chronic denervation of her right tongue and pharynx. During the evaluation process, she developed diplopia from a right cranial nerve VI palsy. Repeat imaging revealed progression of the skull base lesion with extension into the right sphenoid sinus. An endoscopic sphenoidotomy was performed to obtain tissue. The diagnosis of high-grade osteosarcoma was made by histologic morphology and immunohistochemistry. The child was treated primarily with chemotherapy. Other adjunctive therapies are being considered. Osteosarcoma of the skull base is a rare entity. We describe a case of a high-grade clival osteosarcoma presenting primarily with lower cranial nerve palsies and pain. The rapid progression, treatment options, and prognosis are discussed.     

Allergic fungal rhinosinusitis infiltrating anterior skull base and clivus

Bone erosion and skull base invasion are often suggestive of a malignant mass in paranasal and nasal cavities. Nevertheless, forms of chronic rhinosinusitis, such as allergic fungal rhinosinusitis (AFRS), could mimic malignant features. Here, we report AFRS patient with orbital, anterior cranial fossa, Turkish saddle and clivus erosion. A 48-year-old Caucasian female with history of drug-resistant headache, nasal obstruction and anosmia was referred to our institution. Imaging showed hyperdense featureless tissue with signs of medial orbital wall, cribiform lamina and clivus erosions and encasement of right internal carotid artery. Massive amounts of thick and grayish mucoid material were evacuated during surgery. In case of bony erosion, malignancy should always be excluded. Often the correct diagnosis will be obtained only by operative specimens. AFRS could usually be managed endoscopically. Appropriate medical management of the AFRS should be administered in order to prevent relapses.     

岩骨尖上斜坡区域良性肿瘤的病因及诊冶分析

目的介绍21例岩骨尖上斜坡区域良性肿瘤的显微外科治疗结果,就其手术入路进行讨论。方法分析骨尖上斜坡区良性肿瘤的临床特点、神经放射学资料,选择相应的手术入路。结果本组经颞下天幕上入路切除8例,天幕上下联合入路切除7例,枕下入路切除6例。肿瘤全切率为76.2%,术后病死率为4.8%。预后:Ⅰ级2例,Ⅱ级2例,Ⅲ级4例,Ⅳ级4例,Ⅴ级1例。结论根据肿瘤的性质、大小和部位,选择相应的手术入路是十分重要的。联合入路在巨大肿瘤的切除中最为常用。