The Brainstem Cavernoma Case Series: A Formula for Surgery and Surgical Technique.

Background and Objectives: Cavernous malformations (CM) are vascular malformations with low blood flow. The removal of brainstem CMs (BS) is associated with high surgical morbidity, and there is no general consensus on when to treat deep-seated BS CMs. The aim of this study is to compare the surgical outcomes of a series of deep-seated BS CMs with the surgical outcomes of a series of superficially located BS CMs operated on at the Department of Neurosurgery, College of Tuebingen, Germany. Materials and Methods: A retrospective evaluation was performed using patient charts, surgical video recordings, and outpatient examinations. Factors were identified in which surgical intervention was performed in cases of BS CMs. Preoperative radiological examinations included MRI and diffusion tensor imaging (DTI). For deep-seated BS CMs, a voxel-based 3D neuronavigation system and electrophysiological mapping of the brainstem surface were used. Results: A total of 34 consecutive patients with primary superficial (n = 20/58.8%) and deep-seated (n = 14/41.2%) brainstem cavernomas (BS CM) were enrolled in this comparative study. Complete removal was achieved in 31 patients (91.2%). Deep-seated BS CMs: The mean diameter was 14.7 mm (range: 8.3 to 27.7 mm). All but one of these lesions were completely removed. The median follow-up time was 5.8 years. Two patients (5.9%) developed new neurologic deficits after surgery. Superficial BS CMs: The median diameter was 14.9 mm (range: 7.2 to 27.3 mm). All but two of the superficial BS CMs could be completely removed. New permanent neurologic deficits were observed in two patients (5.9%) after surgery. The median follow-up time in this group was 3.6 years. Conclusions: The treatment of BS CMs remains complex. However, the results of this study demonstrate that with less invasive posterior fossa approaches, brainstem mapping, and neuronavigation combined with the use of a blunt "spinal cord" dissection technique, deep-seated BS CMs can be completely removed in selected cases, with good functional outcomes comparable to those of superficial BS CM.

Feasibility and accuracy of a voxel-based neuronavigation system with 3D image rendering in preoperative planning and as a learning tool for young neurosurgeons, exemplified by the anatomical localization of the superior sagittal sinus.

It is essential for a neurosurgeon to know individual anatomy and the corresponding anatomical landmarks before starting a surgery. Continuous training, especially of young neurosurgeons, is crucial for understanding complex neuroanatomy. In this study, we used a neuronavigation system with 3D volumetric image rendering to determine the anatomical relationship between the sagittal suture and the superior sagittal sinus (SSS) in patients with intracranial lesions. Furthermore, we discussed the applicability of such system in preoperative planning, residency training, and research. The study included 30 adult patients (18 female/12 male) who underwent a cranial computed tomography (CT) scan combined with venous angiography, for preoperative planning. The position of the sagittal suture in relation to the SSS was assessed in 3D CT images using an image guidance system (IGS) with 3D volumetric image rendering. Measurements were performed along the course of the sagittal sinus at the bregma, lambda, and in the middle between these two points. The SSS deviated to the right side of the sagittal suture in 50% of cases at the bregma, and in 46.7% at the midpoint and lambda. The SSS was displaced to the left of the sagittal suture in 10% of cases at the bregma and lambda and in 13% at the midpoint. IGSs with 3D volumetric image rendering enable simultaneous visualization of bony surfaces, soft tissue and vascular structures and interactive modulation of tissue transparency. They can be used in preoperative planning and intraoperative guidance to validate external landmarks and to determine anatomical relationships. In addition, 3D IGSs can be utilized for training of surgical residents and for research in anatomy.

Lethal outcome after pelvic salvage radiotherapy in a patient with prostate cancer due to increased radiosensitivity : Case report and literature review.

BACKGROUND: In general, late side effects after salvage radiotherapy (RT) for prostate cancer are below 10%. Patients with impaired DNA repair ability and genetic instability can have significantly increased reactions after RT. CASE, CLINICAL FOLLOW-UP, AND EXAMINATION: We present a patient who experienced severe side effects after additive RT for prostate cancer and died from the complications 25 months after RT. Imaging (MR) is shown as well as three-color fluorescence in situ hybridization. The blood sample testing revealed that radiosensitivity was increased by 35-55%. We undertook a review of the literature to give an overview over the tests established that are currently considered useful. CONCLUSION: This case highlights that the identification of patients with increased radiosensitivity is an important task in radiation protection. Groups of patients who should be screened have to be found and corresponding research facilities have to be set up.

Validation of histologic changes induced by external irradiation in mandibular bone. An experimental animal model.

The present experimental study sought to determine the effect of high-dose irradiation on the rat mandible in order to establish an experimental model of radiogenic bone damage. The left mandibles of 20 adult Wistar rats were irradiated (single fraction 1500cGy, total dose 60Gy) by means of a hypofractionated stereotactic radiotherapy (hfSRT) over a period of 6 weeks. Follow-up was 6 weeks (group 1, n=10) and 12 weeks (group 2, n=10). The contralateral mandibles as well as 5 non-irradiated animals served as controls. Primary endpoints were fibrosis, loss of cell count, decreased immunohistochemical labelling for bone morphogenetic protein-2 (BMP-2) and osteocalcin as well as increased expression of transforming growth factor (TGF-beta). Cell loss, progressive fibrosis, and focal necrosis were detected in all irradiated sites. Quantitative measurement revealed 32.0+/-8.7% and 37.3+/-9.5% empty osteocyte lacunae for groups 1 and 2 resp., compared to 16.3+/-4.7% and 18.9+/-4.9% on the contralateral side and 7.9+/-1.7% for unirradiated controls (Mann-Whitney U test; p<.01). BMP-2 and osteocalcin labelling showed a marked decrease in irradiated and contralateral sides while TGF-beta was expressed strongly in irradiated sites only (for all p<.05). External hypofractionated irradiation with a total dose of 60Gy is feasible in rats and yields all histologic changes attributed to osteoradionecrosis (ORN) after a follow-up of 6 weeks. The irradiation protocol is suitable for an assessment of regenerative options in severe radiogenic bone damage. As a split mouth design entails major inaccuracies healthy animals have to be used as controls.

Stereotactic radiotherapy for the treatment of nonacoustic schwannomas.

OBJECTIVE: Nonacoustic schwannomas are rare tumors in contrast to the most common neuromas of Cranial Nerve VIII. The current treatment of choice in these cases is microsurgical resection, but the risk of postoperative complications is high, especially in cavernous sinus-invading tumors. In many of these cases, it is not possible to achieve complete tumor removal, resulting in the probability of recurrences. For those patients, radiosurgery (RS) or stereotactic radiotherapy (SRT) can offer an alternate treatment. METHODS: Within a 5-year period (2000-2005), 19 intracranial nonacoustic neuromas were treated with SRT-13 trigeminal neuromas, five neuromas of the lower cranial nerves (jugular foramen), and one located in the orbital region. Of these cases, there were nine women and 10 men who were, on average, 54 years of age (range, 33-83 yr). Eight patients had previously undergone surgery elsewhere and showed progressive tumor growth. All 19 patients were treated with SRT: 15 with normal fractions of 1.8-2 Gy single dose up to 54-59.4 Gy. Their irregular tumor volume ranged from 4.2 to 43.1 ccm (average: 14.1 ccm). Hypofractionation with 6 to 7 x 5 Gy was applied in four cases with an average tumor volume of 4.1 ccm (2.2-6.2 ccm). Clinical results and the efficacy for tumor control with an average follow-up of 35 months (11-63 mo) were evaluated. RESULTS: Local tumor control rate was 95% (18 of 19 cases): one patient previously operated on had a recurrence of tumor progression after SRT, followed by a second subtotal resection. A tumor regression was proved in 11 cases (one neuroma disappeared and four patients had tumor shrinkage of more than 50%, the other six experienced shrinkage between 20% and 40%). Within the first 6 months, two patients developed temporarily increased tumor volume as well as a confirmed reaction to irradiation. In one of these two cases, there were mild side effects according to CTC Grade I. No patient experienced a new or increased neurological deficit. Improvement of their cranial nerve disturbances was achieved in 11 of 19 patients and the other eight showed no clinical changes. The mostly moderate trigeminal pain decreased slowly. CONCLUSION: SRT is a low-risk and effective treatment option for intracranial neuromas. Particularly in cases of sinus cavernous-invading trigeminal and in jugular foramen tumors, SRT can be the treatment of choice. Concerning tumor regression, SRT is as effective as RS.

Hypofractionated stereotactic radiotherapy for brain metastases--results from three different dose concepts.

PURPOSE: To evaluate efficacy and toxicity of hypofractionated stereotactic radiotherapy (hfSRT) with three different dose concepts for irresectable brain metastases not amenable to radiosurgery (SRS) using non-invasive fixation of the skull. PATIENTS AND METHODS: From 6/2000 to 6/2005, 150 patients with 228 brain metastases were treated at the dedicated stereotactic radiosurgery system Novalis (BrainLAB, Feldkirchen, Germany) in two German treatment centers. Three different dose concepts were applied: 5 x 6-7 Gy (A: 72 brain metastases), 10 x 4 Gy (B: 59 brain metastases) and 7 x 5 Gy (C: 97 brain metastases). Median planning target volume (PTV) was 6.1 cm(3) (range, 0.02-95.97). RESULTS: Rates of complete remission (CR), partial remission (PR), no change (NC) and progressive disease (PD) were 42%, 30%, 21% and 7%, respectively (median follow-up 28 months). Median survival was 16 months. Survival at 6 and 12 months was 83% and 66%, respectively. Side effects were dependent on the PTV and on dose concept (median PTV in case of increasing edema or necrosis: 17 cm3, A: 22%, C: 7%). HfSRT with 10 x 4 Gy (B) was well tolerated without side effects. CONCLUSION: Hypofractionated stereotactic radiotherapy is an effective and safe treatment. In case of brain metastases >15 cm(3) (diameter >3 cm) and concerning toxicity, 10 x 4 Gy seem to be more advantageous than shorter fractionation with higher doses while 5 x 6-7 Gy and 7 x 5 Gy were followed by higher response rates. Further specification of tolerance doses and tolerance according to the different brain regions has to be done.