Localization of precentral gyrus in image-guided surgery for motor cortex stimulation.

According to recent clinical data, motor cortex stimulation (MCS) is an alternative treatment for central pain syndromes. We present our minimal invasive technique of image guidance for the placement of motor cortex stimulating electrode and assess the clinical usefulness of both neuronavigation and vacuum headrest. Neuronavigation was used for identification of precentral gyrus and accurate planning of the single burr-hole. The exact location was reconfirmed by intraoperative phase reversal of somatosensory evoked potential (SSEP) and clinical response after electrical stimulation test. Implementation of navigation technique facilitated localization of the precentral gyrus with a high degree of accuracy. Determination of stimulating electrode placement was possible in every case. Postoperative clinical and neuroradiological evaluations were performed in each patient. All patients experienced postoperative relief from pain. Our preliminary series may confirm image guidance as a useful tool for surgery of MCS. Additionally, minimal and safe exposure can be performed using a single burr-hole and vacuum head rest.

Surgical management of dural arteriovenous fistulas with transosseous arterial feeders involving the jugular bulb.

Dural arteriovenous fistulas located in the vicinity of the jugular foramen are complex vascular malformations and belong to the most challenging skull base lesions to treat. The authors comprehensively analyze multiple features in a series of dural arteriovenous fistulas with transosseous arterial feeders involving the jugular bulb. Four patients who underwent surgery via the transcondylar approach to treat dural arteriovenous fistulas around the jugular foramen were retrospectively reviewed. Previously, endovascular treatment was attempted in all patients. The success of the surgical treatment was examined with postoperative angiography. Complete obliteration of the dural arteriovenous fistulas (DAVFs) was achieved in three patients, and significant flow reduction in one individual. All patients had a good postoperative outcome, and only one experienced mild hypoglossal nerve palsy. Despite extensive bone drilling, an occipitocervical fusion was necessary in only one patient with bilateral lesions. The use of an individually tailored transcondylar approach to treat dural arteriovenous fistulas at the region of the jugular foramen is most effective. This approach allows for complete obliteration of the connecting arterial feeders, and removal of bony structures containing pathological vessels.

Image-guided ultrasonography for recurrent cystic gliomas.

BACKGROUND: Long-term survival of patients with recurrent gliomas depends on the extent of resection. Thus, the desirability of an intra-operative imaging modality that can augment the resection extension without affecting vital surrounding structures is more than obvious. It was the aim of the present study to evaluate a possible benefit of image-guided intra-operative ultrasonography for the surgery of recurrent gliomas. METHOD: The authors performed ultrasonography-assisted image-guided resection of recurrent gliomas in 16 patients. An ultrasound device (IGSonic) was integrated into the VectorVision2 navigation system (BrainLAB, Heimstetten, Germany). The IGSonic Probe 10V5 was connected to the VectorVision Navigation station via an IGSonic Device Box. Following patient registration, MRI based neuronavigation was used to determine the skin incision and the bone flap. Before opening the dura, the underlying structures were explored by ultrasound combined with the corresponding MR images. The navigated ultrasound displayed the sonographic image of the intracranial anatomy on the navigation screen in a composed overlay fashion. FINDINGS: The integration of intra-operative ultrasound into neuronavigation system offered quick and helpful intra-operative images in all 16 procedures. Due to the specific ultrasonic characteristics of the solid and the cystic parts, our technique created highly useful images in 10 patients with cystic recurrences. In these, user friendly images were obtained that were easy to understand even for neurosurgeons without major experience in intra-operative ultrasound. CONCLUSIONS: Neurosonography is a time- and cost-effective technology offering intra-operative imaging. The improved orientation and visualization of tumour remnants, adjacent ventricles, and the enhanced intra- and peri-tumoural vasculature is one of the main advantages of ultrasonography-assisted image-guided surgery, which is most obvious during surgery for cystic gliomas.

Comparative experimental study of argon plasma and bipolar coagulation techniques.

BACKGROUND: Argon plasma coagulation (APC) is based on the principle of ionised argon creating conductive plasma between an activating electrode and tissue surface and is used as an effective alternative coagulation technique in various surgical disciplines. This trial aims to compare thermal injury in rat brain caused by APC and conventional bipolar coagulation technique. METHODS: A controlled study design with constant power setting and application time was established. Twenty rats were randomised into the APC and bipolar groups. Each group of ten rats had 20 treated lesions. Early and late histopathological changes, as well as maximum extent of the lesion after 48 hours (h) and 12 days were studied in overall 20 lesions. FINDINGS: Although the maximum depth of the lesions was different in APC (2.2 mm) and bipolar (1.8 mm) groups after 48 h, this did not achieve statistical significance (p=0.151). The superficially coagulated area was significantly larger after APC compared with the bipolar technique at the 48 h time point (p=0.032). After twelve days there were no differences in penetration depth (p=0.310) or coagulated area (p=0.222). CONCLUSION: Tissue defects after APC application on rat brains were comparable to conventional bipolar technique in this trial. The results suggest that argon plasma coagulation (APC) is an effective coagulation technique.

Double electrodes simultaneous stimulation and implantation technique in deep brain stimulation.

Posttraumatic tremor is often one of the causes of disability in head injury patients. Usually, pharmacotherapy for this type of tremor is not effective. Since early 1970s, surgical ablation of the ventral thalamus has been used to treat various types of tremor. Nowadays, deep brain stimulation (DBS) confirms its efficacy in alleviating different forms of tremor, including posttraumatic tremor. Such therapy has been reported achieving around 80% success rate in the treatment of posttraumatic tremor. These successful results suggest that the application of DBS therapy can be considered as one of the alternative treatments for minimizing the tremor occurring from different pathologies.

Argon plasma coagulation (APC) in brain tumor surgery: experimental study and clinical experiences.

OBJECTIVE: The present study aims to provide preliminary results of the thermal effects on rat brain tissue after argon plasma coagulation (APC). It also presents and discusses the clinical experiences in the treatment of brain tumor using APC. MATERIALS AND METHODS: A controlled study of APC in the rat brain was conducted. Twelve rats were randomly divided into 2 experimental groups. In the first group (n = 6), histopathological evaluation was performed 2 days following the coagulation. In the second group (n = 6), the evaluation was performed 12 days post operation. In a prospective study of APC-treated tumor tissue in 3 patients, the depth of plasma penetration and histological alteration were evaluated. RESULTS: In the animal experiment, extent of tissue defect became significantly smaller after 12 days (p = 0.010). The maximum depth of tissue alteration after APC application was limited to 2.15 mm (range: 1.5-2.15 mm) at day 2. The histological alteration of tissue after the thermal injury can be divided into 3 zones. In addition, the depth of tissue alteration in the APC-treated human brain tumor was measured in vertical and horizontal planes under light microscope. Similar to the animal experiment result, penetration of the plasma energy in human brain tumors was limited to a maximum of 2.13 mm (range: 1.6-2.13 mm). CONCLUSION: The limited depth of energy penetration may confirm APC as a safe and beneficial tool for coagulation of human brain tissue. However, further clinical studies are required to evaluate the suitability and indications of this method in brain tumor treatment.

Image-guided motor cortex stimulation in patients with central pain.

According to recent clinical data, motor cortex stimulation (MCS) is an alternative treatment for central pain syndromes. We present our minimally invasive technique of image guidance for the placement of the motor cortex-stimulating electrode and assess the clinical usefulness of both neuronavigation and vacuum headrest. Five patients suffering from central pain underwent MCS with the guidance of a frameless stereotactic system (BrainLab AG, Munich, Germany). The neuronavigation was used for identification of the precentral gyrus and accurate planning of the single burr hole. The exact location was reconfirmed by an intraoperative stimulation test. Postoperative clinical and neuroradiological evaluations were performed in each patient. The navigation system worked properly in all 5 neurosurgical cases. Determination of the placement of stimulating electrode was possible in every case. All patients obtained postoperative pain relief. No surgical complication occurred, and the postoperative course was uneventful in all patients. This preliminary experience may confirm image guidance as a useful tool for the surgery of MCS. Additionally, minimal and safe exposure can be achieved using a single burr hole and vacuum headrest.

Clinical application of neuro-navigation in a series of single burr-hole procedures.

With recent developments in computer technology and the improvement of neuroimaging, modern optical neuro-navigation systems are increasingly being used in neurosurgery. In this study, we present our experience with 51 operations using a frameless optical navigation system in a variety of single burr-hole procedures. The procedures include neuroendoscopic surgery, frameless stereotactic biopsy, cyst aspiration and catheter placement. Both the VectorVision and the VectorVision(2) neuro-navigation systems (BrainLab AG, Munich, Germany) were used. The reliability and accuracy of the neuro-navigation system, postoperative complications and the clinical usefulness of image-guidance were analyzed. The navigation system worked properly in all 51 neurosurgical cases. Exact planning of the approach and determination of the ideal trajectory were possible in all cases. The mean registration error of the system, given as a computer-calculated value, was 2.1 mm (0.4-3.1 mm). Postoperative clinical evaluations and imaging were performed on every patient in order to confirm the success of the surgical procedure. All patients recovered well and without any postoperative complications. We conclude that image guidance in single burr-hole procedures provides a high degree of accuracy in lesion targeting, permits good anatomical orientation and minimizes brain trauma. The navigation system has proven to be a helpful tool since it increases the safety of single burr-hole procedures.