Computer tomography-controlled stereotactic surgery

In computed tomography (CT)-controlled stereotactic surgery, the coordinate system of the CT scanner is applied to determine the target depth and direction as well as for readjustment of final probe direction. This method can be used for all types of stereotactic surgery for the brain.     

Neuroleptic analgesia for stereotactic surgery

This report describes the technique of neuroleptic analgesia which was used to perform a variety of stereotactic procedures. The method provides optimal operating conditions for the surgeon while maintaining a high degree of physiologic and neurologic stability for the patient. 51 patients in our series underwent various stereotactic procedures with no intraoperative complications or postoperative morbidity.     

Single-scan stereotactic tumor biopsy and brachytherapy

Stereotactic tumor biopsy and brachytherapy catheter implantation can be accomplished with targets derived from computed axial tomography and magnetic resonance scans. Computer manipulation of image data allows both diagnostic and therapeutic procedures to be carried out from a single set of scan slices. This eliminates the need for repeat scanning as part of the surgical procedure. Microcomputer technology is sufficiently advanced to handle the images and graphics necessary for stereotactic neurosurgery. A system based on the IBM PC/AT designed for this purpose uses readily available graphics software and custom-designed imaging programs. Direct loading of computed axial or magnetic resonance scan images from magnetic tape can be accomplished. Determination of points, contours and volumes in three-dimensional space allows intraoperative alignment of image data and patient landmarks within the stereotactic head frame using pattern recognition overlays. Three-axis scaling for magnification correction along with rotational and linear data transformations provide the basis for single-scan stereotaxis. Interactive computer graphics integrate image, patient and frame coordinates for target determination. This method eliminates the need to design and fabricate nonmagnetic or radiolucent scanner-compatible devices.     

Intracranial chordoma: radiosurgery,hypofractionated stereotactic radiotherapy and treatment outcomes

BackgroundThe aim of the study was to assess the results of stereotactic radiosurgery and hypofractionated stereotactic radiotherapy (SRS/SRT) for skull base chordomas.Materials and methodsTwenty-three patients aged 12–75 were treated with SRS/SRT due to skull base chordoma. In 19 patients SRS/SRT was a part of the primary therapy, while in 4, a part of the treatment of recurrence. In 4 patients SRS/SRT was used as a boost after conventional radiotherapy and in 19 cases it was the only irradiation method applied. Patients were irradiated to total dose of 6–35 Gy and median total equivalent dose of 52 Gy.ResultsDuring median follow-up of 39 months, 4 patients died. One-, two- and five-year OS was 95%, 89% and 69%, respectively. In nine patients, progression of the disease was diagnosed during study period. One-, two- and five-year progression free survival (PFS) from the end of radiotherapy was 81%, 59% and 43%, respectively. Radiotherapy was well tolerated and only two patients in our group experienced moderate treatment-related toxicity.ConclusionSRS/SRT alone or in combination with surgery is a safe and effective method of irradiation of patients with skull base chordomas. High EQD₂ is necessary to achieve satisfactory treatment results.     

A new apparatus for CT-guided stereotactic surgery

Combining whole-body CT scan with a stereotactic system, the authors have developed and applied clinically an apparatus which readily provides intraoperative CT images, making it possible to confirm the location of the target point and ascertain the intraoperative environment. It takes about 9 s to obtain a CT image. Our purpose is to make stereotactic surgery, a kind of blind surgery, as safe and reliable as a visualized procedure by intraoperative CT scanning. By the method, in which there is very little invasion under local anesthesia, evacuation of deep-seated intracerebral hematomas as well as brain abscesses and also biopsy or brachytherapy of brain tumors in the brain can be done with safety and reliability.     

A survey of infections in stereotactic surgery

In 365 consecutive intracranial stereotactic procedures over a 6-year period, there were three postoperative infections; 1 case of increased neurological deficit and 1 of fatality. Staphylococcus aureus was the most common organism involved; however, multiple organisms were seen in 2 cases. Multiplicity of organisms necessitated the use of a broad spectrum of antibiotics in the preoperative and postoperative periods. The method described has permitted an infection rate which compares favorably to other reports in the literature. Perioperative antibiotics, antibiotic-containing irrigation solutions, and careful attention to sterile techniques seem to be instrumental in maintaining a low infection rate in our study. Since the new spheroid design has been used, there have been no infections.     

CT-guided stereotactic surgery for evacuation of hypertensive intracerebral hematoma

During the last 3 years, 46 cases of hypertensive intracerebral hemorrhage were treated by CT-guided stereotactic surgery. Our present report is concerned with the evaluation of this procedure in the treatment of hypertensive intracerebral hematoma, in terms of the rate of aspirated hematoma and follow-up study of patients. It is difficult to draw any definite conclusion about the operative indications. CT-guided stereotactic aspiration, however, can be evaluated as a less invasive and more definitive treatment of intracerebral hematoma in the basal ganglia and thalamus.     

The impact of computer and imaging technology on stereotactic surgery

Computers, particularly medical imaging techniques, have created a renaissance in stereotactic surgery. Human stereotaxis was primarily developed and performed beginning in the 1940s for functional disorders. Interest waned in the 1960s following the introduction of L-dopa until computer-based three-dimensionally precise tomographic modalities (specifically computed tomography) were introduced beginning in the mid-1970s as a routine diagnostic aid. New image-compatible hardware and instrumentation were introduced along with techniques and associated software for relating points and volumes appearing on these diagnostic images into stereotactic space. This paper reviews the computer and imaging technology that has led to this renaissance and discusses some of the important features of a computer-interactive stereotactic system.     

Intracranial and intraspinal dissemination of an ACTH-secreting pituitary tumor.

A case of a 29-year-old man with an ACTH-producing pituitary tumor disseminated into the subarachnoid space is described. After total adrenalectomy for Cushing's disease at the age of 15, Nelson's syndrome developed. Transsphenoidal adenomectomy at 17 and 21 years of age, pituitary irradiation and medical therapies with sodium valproate, baclofen and bromocriptine failed to lower his plasma ACTH level. Multiple intracranial and intraspinal tumors associated with the symptoms of left hemiparesis developed. The removal of a tumor grown at the level of C1-3 was performed with successful palliation of his symptoms. Histologically, the tumor cells showed sinusoidal, papillary and diffuse patterns with a preponderance of the former over the latter two, although the papillary pattern predominated in the primary pituitary tumor. Immunohistochemical analysis demonstrated most cells to be positive for ACTH in the metastatic tumor as well as the primary adenoma. The clinical significance of his course is discussed with a review of 11 reported cases with metastatic ACTH-producing pituitary tumors.     

Diagnosis and treatment of brainstem mass lesions by CT-guided stereotactic surgery

Current neuroradiographic techniques including computed tomographic scanning (CT) and magnetic resonance imaging (MRI) when added to the clinical neurologic examination can localize precisely even small lesions within the brainstem. While the clinical-radiographic diagnosis is accurate with respect to locale, it is often in error with respect to the pathologic nature of the solitary brainstem lesion. Therefore, empiric treatment without the benefit of a tissue diagnosis will often be inappropriate. CT-guided stereotactic surgery can safely and reliably provide a tissue diagnosis in such cases. Furthermore, in selected cases, therapeutic interventions can be of substantial and lasting benefit to the patient.     

Computerized graphic display of physiological data collected during human stereotactic surgery.

An on-line computerized graphic display has been developed for use during stereotactic operations. This depicts in the form of figurine charts and alph-numeric symbols, appropriately oriented on saggital brain diagrams, the results of serial threshold stimulation of the brain. The display facilitates choice of target sites and the data can be stored in a tape library from which search-and-plot programs can be activated for any type or combination of types of response.     

Microcomputer stereotactic atlas

A stereotactic atlas to determine thalamic target sites has been incorporated into a microcomputer. Variability studies of the thalamus with mean and standard deviations of nuclear borders are depicted graphically for overlay onto operative images. Internal landmarks traditionally used to reference target points for functional stereotaxis may be determined by conventional ventriculography or derived from magnetic resonance scans. Modeling of polyline vertices established from gray scale contour mapping and atlas reconstructions further enhance the spatial understanding of relationships to midline structures. Computer integration of anatomic reference points, graphically depicted images and stereotactic atlas data into head frame coordinates can be accomplished. This method is consistent with established stereotactic techniques and allows the visual conceptualization of imaged and graphic data for functional stereotaxis.     

The position and organization of motor fibers in the internal capsule found during stereotactic surgery.

Data gathered from exploratory stimulation of the diencephalon in 130 stereotactic operative procedures have been studied, with the aid of a computer graphic technique, to show the position and topography of motor responses in the internal capsule. The results obtained indicate that pyramidal fibers are organized into a rostral-caudal face-arm-leg sequence and occupy a short compact band in the caudal third of the posterior limb of the internal capsule. This is in contrast to previous concepts of the position of these fibers in the capsule.     

Three-dimensional reconstruction of neuroradiological data within a stereotactic frame of reference for surgery of visible targets

Three-dimensional information obtained with neuroradiological exams performed under stereotactic conditions is displayed on a surgical console within the graphic reconstruction of the geometry of stereotactic frames. Planning of convenient probe trajectories can be carried out taking into account all data derived from different diagnostic techniques.