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Stereotactic craniotomy and intraoperative lesion localisation using the Brown-Robert-Wells frame. Technical note.

A simple technique of stereotactic craniotomy and intraoperative lesion localisation that uses the Brown-Robert-Wells (BRW) stereotactic frame is presented. The method optimises craniotomy placement and facilitates localisation of small intracerebral lesions. Using the system, 16 patients have had resection of intracranial neoplasms from deep and/or eloquent areas of the brain with no neurological morbidity.

Adult↗

Stereotaxis and tomography. A technical note.

A method for stereotactic coordinate determination by means of X-ray tomography is presented. A standard stereotactic method has been slightly modified, and the localization procedure has been adapted to CT scanning as well as conventional tomography. The technique allows rapid and accurate determination of the instrument coordinates of the target by the surgeon and may be used in conjunction with any standard CT body scanner or X-ray tomograph.

Brain↗

Stereotactic endoscopy applied to operations of herniated lumbar disks: technical note.

A modification of the standard Laitinen stereotactic device is described for use in three-dimensional localization of a herniated lumbar disk. A similar alteration of several other stereotactic devices into a 'whole body,' which would be applicable to endoscopic operations of the lumbar spine, could be easily done, if the frame includes a semicircular arc with a radius of 15 cm or more.

Endoscopes↗

Lateral orthogonal approach for depth electrode insertion using the Leksell frame: technical note.

A simple device is described to perform lateral orthogonal approaches using the Leksell stereotactic frame. This device is especially useful for simultaneous bilateral insertion of intracerebral electrodes without the need for attaching the stereotactic arc. It also allows for targeting of far lateral lesions that lie beyond the limits imposed by the arc and is compatible with all recent models of and accessories for the Leksell frame.

Craniotomy↗

Transoral stereotactic biopsy of the second cervical vertebral body: case report with technical note.

Although the transoral approach to the atlantoaxial region is generally an open surgical procedure, in patients in whom only tissue diagnosis is required, a needle biopsy can be done. In this paper a patient with a metastatic lesion in the second cervical vertebral body is presented, and the technique for needle biopsy of the second cervical body using stereotactic methods is described.

Adenocarcinoma↗

MR-based stereotactic mesencephalic tractotomy.

INTRODUCTION: Medically refractory pain related to cancer is a major indication for pain surgery. Stereotactic mesencephalic tractotomy (SMT) constitutes a widely accepted procedure in treating unilateral head and neck cancer pain. MATERIAL AND METHOD: We report a case of a MRI-based right-sided SMT for treating intractable craniofacial pain, in a 38-year-old patient, related to a previously resected adenocystic carcinoma of the parotid gland. The patient had undergone an implantation of an intrathecal morphine/clonidine pump and subsequent radiofrequency cingulotomy with only temporary improvement. Prior to SMT the patient developed left-sided chest wall pain, secondary to metastasis, in addition to her left-sided facial, dysesthetic pain. The MRI-based SMT was performed with the assistance of a side-extruding monopolar electrode (Leibinger GmbH, Freiburg, Germany) for intraoperative, topographic mapping of the spinothalamic tract. Two lesions were made at 8 and 5 mm off the midline on the right side at the level of the superior colliculus at 70 degrees C for 90 s with a 2 x 4 mm radiofrequency bipolar electrode (Leibinger GmbH). RESULTS: The patient developed intraoperatively left-sided facial, bodily and extremity thermoanalgesia. She had an unremarkable postoperative course. No early proprioceptive or gaze deficits were noted. Her facial and truncal pain was well controlled with intrathecal morphine and clonidine at the preoperative dosology for 17 months. Left-sided upper extremity dysesthesia developed 15 months after the procedure. The patient expired 18 months after this procedure due to an extensive metastatic disease. CONCLUSIONS: The use of high-resolution MRI (MPRAGE) and side-extruding electrode represent technical maneuvers that could decrease the morbidity and further improve the long-term outcome of SMT in treating patients with chronic, medically refractory cancer pain, who have a likely survival time in the order of 1 year +/- 6 months.

Adult↗

Atlantoaxial stabilization in rheumatoid arthritis.

Atlantoaxial subluxation in patients with rheumatoid arthritis is common. Operative stabilization is clearly indicated when signs and symptoms of spinal cord compression occur. However, many recommend early operative fusion before evidence of appreciable neural compression occurs because 1) the myelopathy in these patients may be irreversible; 2) the overall prognosis is poor once symptoms of cord compression are present; and 3) the risk of sudden death associated with atlantoaxial subluxation is increased even in asymptomatic patients. The authors believe that rheumatoid arthritis patients in relatively good health without advanced multisystem disease and less than 65 years of age should be considered for operative stabilization if mobile atlantoaxial subluxation is greater than 6 mm. Seventeen patients with severe rheumatoid arthritis and atlantoaxial subluxation treated with a posterior arthrodesis are presented. A new method of fusion, devised by the senior author (V.K.H.S.), was utilized in all cases. Indications for operative therapy in these patients included evidence of spinal cord compression in 11 patients (65%) and mobile atlantoaxial subluxation greater than 6 mm but no signs or symptoms of cord compression in six patients (35%). Thirteen patients developed a stable osseous fusion, two patients a well-aligned fibrous union, one patient a malaligned fibrous union, and one patient died prior to evaluation of fusion stability. The details of the operative technique and management strategies are presented. Several technical advantages of this method of fusion make this approach particularly useful in patients with rheumatoid arthritis. Because of multisystem involvement of this disease, a high rate of osseous fusion is often difficult to achieve.

Adult↗

Technical and clinical aspects of CT-directed stereotaxis.

A system has been developed for using computed tomography to direct stereotactic neurosurgical procedures. This system operates with many commercially available CT body scanners and does not require any modification to be made to either the scanner or its computer software. The use of this system does not require rigid fixation of the patient to the scanner nor meticulous patient positioning in the scanner.

Biopsy, Needle↗

Clinical experience with interactive teleconsultation and teleassistance in craniomaxillofacial surgical procedures.

PURPOSE: The objective of this study was to evaluate the clinical value and feasibility of surgical telenavigation and teleassistance technology in the field of craniomaxillofacial surgery. MATERIALS AND METHODS: The technology is based on the principles of augmented reality environment technology and remote stereotactic visualization. A consultant surgeon in a remote location receives video, audio, and stereotactic navigation data from the operation site almost in real-time and, using a head-mounted display, is emerged in the surgical augmented reality environment. By telepresence or teleconsultation, the composite images and superimposed graphics (instruments, target structures, landmarks, contours) can be seen and discussed in connected clinics with the possibility of interactive manipulation and assistance. RESULTS: Interactive teleassistance was used in 27 cases of various types craniomaxillofacial surgery. The principles of computer-aided telenavigation were applied successfully. Technical problems in 6 cases did not cause a breakdown of overall system performance. CONCLUSION: Teleconsultation with remote experts is a useful tool, although some shortcomings exist. The financial and personal effort involved is considerable.

Computer Graphics↗

A simple three-dimensional display model based on recorded CT scan films for surgical reference technical note.

A simple method of making a three-dimensional display model of recorded computerized tomography (CT) scan films is presented. The reconstructed display model provides useful information as to surgical approaches to intracranial mass lesions. The actual size and three dimensional shape of a lesion and its topographical relationship to surrounding brain structures are easily grasped by directly handling this model.

Adult↗

Circular stereotactic callosotomy: a preliminary report. Technical note.

The authors propose a new method for performing stereotactic callosotomy, which they have named circular callosotomy. The operating device is the original Riechert-Mundinger's string electrode, which can be protruded through a side window and by rotating the probe it is possible to cut the commisural pathways to the extent required. The anatomical results of the operation can be checked using MRI scanning.

Corpus Callosum↗

[Stereotactic mapping for radiosurgical treatment of vestibular schwannomas].

RATIONALE: As an exclusively image-guided surgery method, radiosurgery requires special attention in the choice of imaging modalities and acquisition parameters must be set with extreme care. METHODS: Quality control for resolution and accuracy of computed tomography (CT) scanners must be performed. Magnetic resonance imaging (MRI) distortions should be limited through magnetic field homogeneity adjustment (shimming) and acquisition parameters optimization. These inaccuracies should then be quantified through systematic combination of MRI and CT in the radiosurgery planning system. MRI pulse sequences selection criteria are defined by their ability to delineate tumor contrast enhancement and to image cranial nerves and vessels relative arrangement in the cistern and canal. Topography of the petrous structures, such as cochlea, vestibulum and facial nerve canal should be visible. Exact definition of real extension of the lesion at the end of the canal may require specific technical solutions. These technical requirements must be balanced depending on the lesion Volume staging (Koos), the treatment history (microsurgery), the clinical condition (hearing quality), the pathological context (NF2) or the age of the patient. RESULTS: T1-weighted Volumetric MRI pulse sequences (3D-T1) show a contrast enhanced signal that is useful for both the pons interface delineation in Koos III cases, and the canal ending in Ohata A and B. On the other hand, 3D-T1 introduce inaccuracies from magnetic susceptibility distortions and partial Volume effects. High resolution CISS T2-weighted Volumetric pulse sequences (3D-T2) give superior stereotaxic definition attributable to their better resolution (half a millimeter) minimizing partial Volume effects and to their lower magnetic susceptibility minimizing distortions. 3D-T2 allows direct nerve visualization. Moreover, this pulse sequence with contrast injection, show improved distinction between the pons and the nerves due to signal differences within the schwannomas. Fat saturation pulse sequences are of interest in post-microsurgery conditions. CONCLUSIONS: Radiology phase quality is critical and its complexity requires a high commitment to obtain satisfactory clinical results. Solelt the 3D-T1 MRI modality seems to us not to comply to minimum security criteria.

Diffusion Magnetic Resonance Imaging↗

Experience in fractionated stereotactic body radiation therapy boost for newly diagnosed nasopharyngeal carcinoma.

PURPOSE: Radiotherapy is the most effective treatment for nasopharyngeal carcinoma (NPC). The aim of this study is to evaluate the efficacy and toxicity of fractionated stereotactic body radiation therapy (SBRT) boost for NPC. METHODS AND MATERIALS: Sixty-four patients with newly diagnosed, nonmetastatic NPC were treated with conventional radiotherapy 64.8-68.4 Gy followed by fractionated SBRT boost 12-15 Gy between January 2002 and July 2004. Most patients (72%) presented with Stage III-IV disease. Fifty-two patients also received cisplatin-based concurrent (38) or neoadjuvant (14) chemotherapy. The major endpoints were local control, overall survival, and complications. RESULTS: All patients finished the planned dose of radiotherapy. After a median follow-up of 31 months (range, 22-54), 15 patients developed tumor recurrences--3 in the nasopharynx, 4 in the neck, 5 in distant sites, 1 in both nasopharynx and neck, 2 in the neck and a distant site. The 3-year actuarial rate of local control was 93.1%, regional control 91.4%, freedom from distant metastasis 90.3%, and overall survival 84.9%, respectively. There were no Grade 4 acute or chronic radiation-related complications. CONCLUSIONS: Fractionated SBRT boost for NPC is technically feasible and provides good local control without any severe complications.

Adult↗

Experience with MR-guided therapy.

The use of magnetic resonance imaging (MRI) for the real time guidance of surgical procedures is now undergoing clinical trials. Among the many procedures explored, open craniotomy neurosurgery appears to be among the most promising. Over 50 such cases have been done at the Brigham and Women's Hospital (BWH) in Boston. We review the technical approach used in these and related procedures. We consider the way in which imaging is used to augment and improve the procedures. As well, the implications of these protocols for remote diagnosis and telesurgery are explored. Finally, the implications of this experience for the insertion of new technology into medicine are discussed.

Biopsy↗

[A universal stereotactic device for spinal cord surgery].

Technical description of a universal stereotactic system for spinal cord operations is presented after a short overview of the history of spinal cord stereotaxis. When combined with the topometric atlas of the cord, new era of spinal cord stereotaxis can be opened, which is going to expand the amount of knowledge about the physiology of the spinal cord.

Equipment Design↗

[Stereotactic 11-gauge directional vacuum-assisted breast biopsy: experience with 249 patients].

PURPOSE: To assess the value of percutaneous vacuum-assisted core biopsy to improve the diagnosis of non palpable mammographic abnormalities. MATERIALS AND METHODS: A total of 252 core biopsies using an 11G Mammotome((R))were performed in 249 patients. Stereotactic localization was performed in the prone position on a dedicated digital Fischer table. RESULTS: Fifty-one, or 25%, of 200 clusters of microcalcifications corresponded to carcinomas: 126 benign lesions, 23 atypical hyperplasia and LCIS, 31 DCIS, 15 invasive ductal carcinomas, and 4 false negative biopsies. In these 4 last cases, surgery was performed because radiographs of the core biopsy showed no microcalcifications; carcinoma was confirmed at histology of the surgical specimen. Using the BI-RADS system, 7 lesions were category 3, 175 lesions were category 4, and 18 lesions were category 5. From a total of 52 masses, 31 were benign lesions, 2 were borderline lesions, and 19 were invasive carcinomas. From these, 5 lesions were category 3, 31 were category 4, and 16 were category 5. Diagnostic surgical biopsy was avoided in 161 cases (63%), in 152 cases for benign lesions including 151 lesions classified as category 4 lesions and in 9 cases for multifocal or recurrent malignant lesions. CONCLUSION: When technical pitfalls are avoided and when presence of microcalcifications in the core biopsy sample is verified, vacuum assisted core biopsy with Mammotome((R)) 11G provides accurate diagnosis of non-palpable mammographic abnormalities.

Biopsy, Needle↗

Radiotherapy of liver malignancies. From whole liver irradiation to stereotactic hypofractionated radiotherapy.

AIMS AND BACKGROUND: Until recently radiotherapy of hepatic malignancies has played a limited role due to the well-known limited radiotolerance of the liver. The aim of this paper is to review the available data on the risk of radiation-induced liver disease (RILD) and to define the modern role of radiotherapy in the management of patients with metastatic or primary liver malignancies. METHODS: The advent of three-dimensional conformal treatment planning with dose-volume histogram analysis has made the study of partial liver irradiation possible. Limited portions of the liver may withstand high doses of radiation with minimal risk of RILD. Patients with solitary unresectable liver tumors may be treated with high-dose radiotherapy with curative intent. Recently, the feasibility of stereotactically guided treatment techniques with a single fraction or few treatment sessions has been explored in numerous institutions. RESULTS: The radiation tolerance of the whole liver found by several investigations is in the order of approximately 30 Gy, which seriously restricts its clinical application. The role of whole liver irradiation therefore appears of limited benefit in the palliation of patients with multiple liver metastases. The use of three-dimensional conformal techniques has made partial liver irradiation possible to doses in the 70-80 Gy range with conventional fractionation. At least two published series have reported improved local control and survival rates with dose escalation with three-dimensional conformal radiotherapy in patients with unresectable liver metastases. Similar outcomes have been recently reported with single dose (or hypofractionated) stereotactic radiotherapy both in metastatic and primary hepatic malignancies with minimal morbidity. Accurate target delineation and treatment reproducibility are the key to the success of this novel treatment approach, and specific treatment planning techniques and patient setup procedures must be developed to implement it. CONCLUSIONS: Stereotactic high-dose radiotherapy is technically feasible for the treatment of inoperable liver malignancies, with the potential of high local control and low morbidity. Definitive evidence on the clinical advantages of this technique over other more established treatments can only be gathered from well-designed clinical studies.

Dose Fractionation, Radiation↗