Skull base surgery

Surgical inaccessibility, the obstacles of vital neural and vascular anatomy, and the overwhelming surgical mortality rate as a result of hemorrhage and sepsis have led surgeons to approach lesions of the skull base with understandable reluctance. We have, however, undergone a technical revolution in microsurgery, anesthesia, and neurodiagnosis. Innovative surgical minds have thus been armed with the technology to make surgery a reasonable alternative for these dreaded lesions. This article singles out the glomus tumor and its associated lesions, which the neuro-otologist must approach transtemporally. Their diagnosis and new treatment concepts are discussed. Old criteria for unresectability are redefined and new classifications are established. Surgery of these skull base lesions is discussed from the standpoint of the basic principles of exposure, hemostasis, and management of the facial nerve. Problems in rehabilitation of postoperative deficits are discussed.     

颅底外科学进展

颅底外科学是20余年来逐渐发展起来的一门新兴交叉学科,是近年来最活跃的外科领域之一。近10余年来已有长足的发展。本文从颅底手术术式研究,内镜在颅底手术中的应用,影像学和立体定向技术对颅底外科学发展的影响等方面回顾10年来我国颅底外科学研究成果。     

Skull base surgery for malignancy: when not to operate

The purpose of this paper is to detail the contraindications for surgery, with curative intent for those patients who suffer from a head and neck malignancy that invades the intracranial space. This is based on a 30-year experience of over 250 patients. The most important contraindications are anatomical. Surgery is not done if the following structures are invaded: brain stem, eloquent portions of the cerebrum, superior sagittal sinus, both internal carotid arteries, both cavernous sinuses and certain vital bridging veins. Certain tumor factors are absolute but are occasionally relative contraindications: such as distant metastatic disease especially if multiple and at multiple anatomic sites. Some tumors that behave in a particularly virulent fashion that defy complete resection but are often difficult to predict preoperatively. Lack of patient medical fitness or absence of patient commitment to the operative procedure is make-up two serious contraindications to surgery. Presented at the 77th Annual Meeting of the German Society for Oto-Rhino-Laryngology, Head and Neck Surgery, 24–28 May 2006, Mannheim, Germany.     

Skull base surgery for removal of temporal bone tumors

CONCLUSION: When selecting the appropriate surgical approach the pathological type of tumor, the physiological status as well as the functional aspects should be considered. Understanding the strengths and weaknesses of each surgical technique and knowledge of the particular tumor biology facilitates selection of the most appropriate surgical approach and a successful outcome. OBJECTIVES: The purpose of this study was to review cases that underwent skull base surgery for a variety of tumors that involved the temporal bone. We reviewed a single center's 25-year experience for epidemiologic characteristics, symptoms, treatment type and outcomes. PATIENTS AND METHODS: The medical records and radiological images of 91 patients, who underwent skull base surgery, were retrospectively reviewed. RESULTS: Among the 91 patients, 61 cases had benign disease and 30 had malignancies. A facial nerve schwannoma was the most common benign intratemporal tumor and a squamous cell carcinoma was the most common malignant tumor. With the facial nerve schwannoma, facial nerve paralysis and hearing loss were the most common presenting complaints; otalgia was the most common presenting symptom for temporal bone cancer. For patients with a glomus tumor, there was a characteristic pulsating tinnitus. A majority of the facial nerve schwannomas were resectable through the transmastoid approach. The infratemporal fossa approach type A was usually required for lower cranial nerve schwannomas and glomus jugulare tumors. However, the fallopian bridge technique with hypotympanectomy was another surgical option. Partial temporal bone resection and subtotal temporal bone resections were performed in cases with temporal bone cancer. The disease free 5-year survival of the temporal bone cancers was 42% and for the squamous cell carcinomas, it was 44%.     

Skull base chordomas

Skull base chordomas are rare midline malignancies of clival origin that represent one of the most challenging skull base tumors to treat, given their location, invasiveness, potential extension around vital neurovascular structures, and high recurrence rate. Total tumor resection is the mainstay of treatment. The combination of surgery and postoperative irradiation appears to provide the best outcome.     

Skull base chordomas

Chordomas are rare, benign tumors of the nasopharynx. Because of their location at the skull base, removal of these tumors is usually subtotal. Described is the transcervical-transmandibular approach to the skull base which can be employed in removing these tumors.     

Skull base mapping

Early experience with medium to large tumors of the temporal region has re-emphasized the value of radiologic preoperative plotting of these space occupying lesions in the sagittal, coronal, and horizontal planes. Attention to probable pathology, neurovascular structures and patient's medical status has been important in determining resectability. A standard format of the interior and exterior of the skull base and cervical spine has been employed to map these lesions. Such devices have been used by otolaryngologists in the past to depict laryngeal lesions; and provide for the skull base surgeon a common base of comparison of tumor size, chart documentation, and a means to facilitate communication among other specialists. Experience with 36 cases of skull base tumors seen since July 1979 has emphasized the occult manner in which these lesions may present.     

Skull base reconstruction

Reconstruction of skull base defects following tumor resection is of paramount importance in avoiding serious and life-threatening complications. Cranial base surgery has evolved and outcomes have steadily improved as increasingly reliable reconstructive techniques have been adapted to repair the challenging wounds in this complex anatomic region. The most significant development has been the introduction and refinement of microvascular free tissue transfer to the skull base over the past 15 to 20 years. Free flaps can reliably provide the requisite tissue to not only seal the intracranial space from the subjacent cavities, but also to restore complex craniofacial defects that often result from skull base tumor excision. Advances in alloplast technology have also expanded the armamentarium available to the reconstructive surgeon. In particular, bone substitutes, titanium hardware, and resorbable plate fixation have been shown to be very efficacious when used in carefully selected situations. Finally, tissue sealants and adhesives have become widely used as an adjunctive method to achieve a water-tight dural repair.     

耳鼻咽喉科医师应该关注的领域--颅底

颅底由额骨眶板、筛骨、蝶骨、颞骨和枕骨构成。内面分成前、中、后颅窝 ,分别上承大脑、中脑和小脑 ,有筛孔、视神经孔、眶上裂、圆孔、卵圆孔、棘孔、枕骨大孔、颈内静脉孔、舌下神经孔和内耳门等孔道和裂隙 ,容脑干及神经血管穿过 ;下为眼眶、鼻腔、鼻窦、鼻咽与耳部之顶壁及颈部骨骼、肌肉与其他软组织。颅底手术涉及到神经外科、耳鼻咽喉科、颌面外科和整形外科等 ,这些学科自然整合在一起 ,构建成一门新的学科 ,称为颅底外科。在上世纪的 6 0～ 70年代 ,耳鼻咽喉科和脑外科医师分别从治疗本学科疾病出发 ,进行了跨颅底病变的手术切除 …     

颅底缺损的修复

目的：探讨颅底缺损的修复技术。方法：回顾性研究30例颅底缺损修复者的临床资料。颅底骨质缺损修补术20例，其中钛网修补12例，自体髂骨修补2例，裂层额骨修补2例，单纯颅骨外膜修补4例；硬脑膜缺损修补6例，其中带蒂颅骨外膜修补3例，带蒂颞肌筋膜修补2例，游离颞肌筋膜修补1例；颞下窝软组织缺损修补8例，其中带蒂颞肌修复颞下窝5例，带蒂颞肌及胸锁乳突肌联合修复颞下窝3例。结果：术后短暂性脑脊液鼻漏3例，无症状性颅内积气3例，少量硬脑膜外血肿及脑膜炎各1例。结论：颅底手术中采用适宜的外科技术和修复材料进行一期颅底修补，对于减少术后感染、脑脊液鼻漏等并发症有重要意义。     

Skull base lesions: a classification and surgical approaches

An anatomic classification of lesions affecting the skull base is proposed according to which this region can be divided into a midline compartment and two lateral compartments: a petrotemporal and an infratemporal. The majority of lesions studied radiographically in 56 patients were confined to one of these anatomic subdivisions. The advantages of such a classification are discussed. The surgical approaches to these compartments and to the anterior middle and posterior cranial fossae are described relative to the lesions we have encountered.     

Skull base approach to glomus jugulare

The skull base approach to the jugular bulb provides a better opportunity to preserve facial nerve function. Specifically, this applies to glomus jugulare tumors. Adequate exposure to remove even an extensive glomus jugulare tumor may be obtained by the skull base approach, working between the VIIth nerve left in its bony sheath and the lateral process of the first cervical vertebra.