Adam Rudnik

Hypofractionated stereotactic radiotherapy for large or involving critical organs cerebral arteriovenous malformations

Abstract Background. The treatment of large arteriovenous malformations (AVMs) or AVMs involving eloquent regions of the brain remains a challenge. For inoperable lesions, observation, volume-staged radiosurgery or hypofractionated stereotactic radiotherapy (HFSRT) are proposed. The aim of our study was to assess the safety and efficiency of HFSRT for large AVMs located in eloquent areas of the brain. Materials and methods. An analysis of records of 49 patients irradiated for cerebral AVMs with a mean dose of 19.9 Gy (12-28 Gy) delivered in 2-4 fractions with planned gap (at least one week) between fractions. Actuarial obliteration rates and annual bleeding hazard were calculated using Kaplan-Meier survival analysis and life tables. Results. Annual bleeding hazard rates were 4.5% and 1.6% after one and two years of the follow-up, respectively. Actuarial total obliteration rates were 7%, 11%, and 21% and total response rate (total and partial obliterations) 22%, 41%, and 55% after one, two and three years of the follow-up, respectively. There was a trend towards larger total obliteration rate in patients irradiated with fraction dose ≥ 8 Gy and total dose > 21 Gy for lesions of volume ≤ 8.18 cm3 which was not observed in case of partial obliterations. Conclusions. HFSRT results with relatively low obliteration rate but is not associated with a significant risk of permanent neurological deficits if both total and fraction doses are adjusted to size and location of the lesion. Predictive factors for total and partial obliterations can be different; this observation, however, is not firmly supported and requires further studies.

The Incidence of Imaging Abnormalities after Stereotactic Radiosurgery for Cerebral Arteriovenous and Cavernous Malformations

OBJECTIVE The aim of the study was to evaluate the incidence of postirradiation imaging changes after stereotactic radiosurgery for arteriovenous malformations (AVM) and cerebral cavernous malformations (CCM). MATERIAL AND METHODS A group of 85 patients treated for arteriovenous malformations (62 patients, 73%) and cavernomas (23 patients, 27%) between October 2001 and December 2005 was analyzed. All patients were treated with stereotactic radiosurgery with doses ranging from 8-28 Gy. After the irradiation, magnetic resonance imaging (MRI) or computed tomography (CT) was performed at 6 to 12-month intervals to assess the effects of the treatment. The mean follow-up time for the whole group was 27.3 months; AVM group -- 26 months; CCM group -- 30.9 months. All the imaging data were carefully reviewed to identify the radiological symptoms of postradiosurgical damage. T2 or FLAIR hyperintensity, T1-hypointensity and contrast enhancement on MRI and the presence of hypodense areas and contrast enhancement on CT examinations were assessed. RESULTS Imaging abnormalities were found in 28 (33%) patients. The symptoms of postradiosurgical damage were observed in 21 (33.9%) patients in the AVM group and 7 (30.4%) patients in the CCM group. Radiological symptoms of radiation necrosis associated with neurological deterioration were identified in two patients with cavernomas, while no radiation necrosis was found in the AVM group. Patients in whom radiological signs of focal brain edema or gliosis existed were asymptomatic. CONCLUSIONS Radiological symptoms of postradiosurgical damage affected about one third of the irradiated patients, typically without any clinical manifestations. Patients irradiated for CCMs seem to be more prone to develop symptomatic postradiosurgical necrosis; this observation, however, requires further investigation.

The Prognostic Value of some Clinical and Diagnostic Factors in Traumatic Intracranial Haematoma

In order to carry out the analysis of predictive values of some clinical and diagnostic features, 146 patients of the Neurosurgical Clinic of the Silesian School of Medicine, were examined in 1980-1986. All the patients were in coma when admitted while CT findings showed traumatic intracranial haematomas. The examination included neurological diagnosis and CT examination. The analysis of statistical discrimination let us specify the probability of predicting death or survival of every patient. On the basis of 10 prognostic factors applied, the compatibility of prognosis and the real outcome for patients who survived was 78.2% and for those who died 91.2%.

Preoperative Planning of Surgical Treatment with the Use of 3D Visualization and Finite Element Method

This chapter describes a method of engineering support of preoperative planning of surgical procedures with the use of engineering tools, such as state-of-the-art software for medical image processing, or a finite element method. The procedure of pre-operative planning consists in matching individual cases of incision sites and directions, visualization and selection of areas for resection as well as planning the technique of implant positioning and fixation. Also, the final visualization of the result of the planned medical procedure can be performed. This paper presents procedural propositions in surgery planning in the cases of corrections of the head shape in patients with craniosynostosis, corrections of the chest deformity such as pigeon chest and stabilization of the lumbar spine. 3D models created on the basis of computer tomography (CT) or magnetic resonance imaging (MRI) enabled it to conduct a biomechanical analysis as well as an objective quantitative and qualitative virtual evaluation of the surgical procedure. Preoperative planning support gives the physician an opportunity to prepare for the operation in a better way, which results in the selection of the best possible variant of an operative technique, reduction of time of the surgical procedure and minimization of the risk of intraoperative complications.