N ervebiopsyhas been helpful in the diagnosis of periarteritis nodosa, amyloidosis, leprosy, metachromatic leukodystrophy, Krabbe's disease, ataxiatelangiectasia, and conditions where the nerve is palpably enlarged. Less information is gained in acutely or subacutely evolving distal symmetrical polyneuropathies of toxic or metabolic origin. Operative Technique The patient should be positioned in the lateral decubitus position slightly inclined toward the prone position with the operative side up. The underneath leg is flexed. A pillow is placed between

P eripheral nervebiopsyis useful in the diagnosis and management of neuromuscular disorders. The nerve selected should be affected by the disease process, display a constant anatomy, be of adequate size, and be one that will produce a minimal deficit. 4 Because of these requirements, the sural nerve in the leg has become the preferredbiopsysite. 1, 5, 10, 12 Unfortunately, its histopathology is generally normal in diseases that preferentially affect the motor fibers such as pure motor neuropathy, motor neuron disease, and, occasionally, sensorimotor

radiographic impressions and not on histological grounds. Surgical approaches to the pons have generally been one of the following: 1) the suboccipital approach via the fourth ventricle; 2) an approach through a retromastoid suboccipital craniectomy via the cerebellar pontine angle; 3) the subtemporal transtentorial technique; or 4) a CT-guided stereotaxicbiopsy。2, 3, 9–11, 18, 20 The open conventional surgical methods carry inherent risks in compromised patients and are associated with a low diagnostic yield. 2, 23, 32, 38 Stereotaxicbiopsyhas been shown effective

C omputerized tomography (CT)-guided stereotacticbiopsyof lesions in the posterior fossa has become a standard diagnostic procedure. 1–3, 5, 6 The transfrontal approach is often employed to reach brain-stem targets. 3, 4, 6 This route, however, is not appropriate for lesions placed far laterally within the brain stem or in the cerebellum. For targets in these areas, the transcerebellar approach has several of the elements required for an ideal stereotactic trajectory: it is short, traverses relatively noneloquent brain tissue, and crosses only one pial

P ainful ophthalmoplegia caused by lesions of the anterior cavernous sinus or superior orbital fissure, frequently with orbital apex extension, may present difficulties of early diagnosis. Principal disease categories to be considered in such cases are neoplastic, vascular, and inflammatory. An abbreviated differential diagnosis is presented in Table 1 . A definitive diagnosis frequently requires histological examination of tissue. When this is not available by other means, fine-needle aspirationbiopsyof the anterior cavernous sinus carried out under

B rainbiopsyprocedures have evolved over the last three decades in conjunction with the ability to image the brain directly. Beginning in the mid-1970s,biopsysampling of lesions in the brain was performed in a freehand fashion by using CT scanning. 14 In the early 1980s, CT scanning was incorporated into stereotactic procedures because it allowed both the precise translation of a three-dimensional database into the three-dimensional coordinate system of a stereotactic frame and the direct visualization of lesions in the brain without inferring their

S tereotacticbiopsyis an effective procedure that allows for accurate localization and sampling of an intrinsic brain lesion. The procedure is ideal for situations in which knowledge of the pathology of a brain lesion is required to guide further decisionmaking regarding therapy but also in the presence of one or more of the following factors: 1) the patient is too old and/or infirm to tolerate craniotomy; 2) the lesion is deep, diffuse, predominantly cystic, located in eloquent cortex, or multiple; and/or 3) cytoreductive surgery is not needed to adequately

D ramatic progress in brain imaging during the last decade has renewed interest in stereotactic brainbiopsy。电脑断层摄影术(CT),它允许早recognition and accurate definition of cerebral lesions, is widely used to guide calculation of stereotactic coordinates with nearly all stereotactic devices presently available. 2, 4, 10, 13, 15 Stereotacticbiopsynow ranks as a low-risk procedure with high diagnostic reliability. In many neurosurgical centers, this is a routine procedure to achieve a histological diagnosis when formal surgery is not