Clinical Experience of Stereotactic Radiosurgery at a Linear Accelerator for Intraocular Melanoma Combined with Iridociliary Tumor Resection: A Case Report

Introduction

The treatment of iridociliary and choroidal melanoma relies on the patient's systemic health, tumor size, location, related features, state of the opposing eye, and personal preferences. The two categories are radiation and surgical techniques. Transpupillary thermotherapy, plaque radiotherapy, charged particle irradiation, local resection, enucleation, orbital exenteration, and experimental nanoparticle therapy are all options for treating choroidal melanoma.

Case Presentation

The method that entails creating a partial thickness circular, rectangular, or polyhedral scleral flap in the region covering the tumor after removing a portion of the extraocular muscles is the most popular method for local excision in choroidal or choroidal-ciliary body cancers. We discuss our experience treating iridociliary melanoma using block excision and stereotactic irradiation on a linear accelerator with TD 20.0 Gy.

Conclusion

One of the treatment modalities is the combined treatment approach using stereotactic irradiation and tumor resection, and our results 1 year after therapy are comparable to the rates of local control and anatomic eye preservation to those achieved in studies of comparable uveal melanoma treatment modalities.

Providing prevention, diagnosis, and treatment of patients after COVID-19 using artificial intelligence

OBJECTIVE

The aim of this research was to investigate the prevention, diagnosis, and treatment of patients after COVID-19 with the possibility of using artificial intelligence and virtual reality in combination with traditional approaches to patient rehabilitation.

MATERIALS AND METHODS

Statistical methods were used to evaluate the situation of COVID-19 worldwide and in Slovakia until March 2022. We investigated the rehabilitation options of breathing exercises, upper and lower limb rehabilitation, and cognitive tasks in patients with post-COVID syndrome who met the criteria for a combined rehabilitation program using virtual reality. Using artificial intelligence, we can predict in advance the evolution of the pandemic according to the records of infected patients and the evolution of the pandemic in the world, taking into account nearby territories. In the treatment of post-COVID syndrome, parameters have been identified that can be measured to objectively assess the improvement of the patient's condition and to continue personalizing individual rehabilitation scenarios.

RESULTS

In the patients who underwent the combined rehabilitation method, we observed progress in their ability to improve breathing, limb motor skills and also cognitive function of the patients. We identified different categories of parameters that can be evaluated by artificial intelligence methods, and we evaluated different scenarios using the exterior of nature and the interior of the room of the rehabilitation method of virtual reality, as well as the key elements of the "WOW" effect creating emotional changes in the patient for their motivation.

CONCLUSION

We showed that artificial intelligence and virtual reality methods have the potential to accelerate rehabilitation and increase motivation in patients with post-COVID syndrome.

Two 11-Years Periods Statistics and Trends of Enucleation and Evisceration

Purpose:

The indications for evisceration and enucleation are still evolving and controversial. The study aims to describe trends of enucleation versus evisceration in one center.

Methods:

In period 1998–2019 were 353 patients were included in the study. Statistical results and Chi-square test for pair-wise comparisons for the statistical significance in comparing two subgroups (years periods 1998–2008 and 2009–2019) per category have been evaluated.

Results:

The enucleation was performed in 306 patients, and the evisceration was performed in 47 patients. In 221 patients with the tumor exclusively enucleation was indicated. For the operation technique, the authors got a chi-square value of 0.027, and the associated P value is at 0.8695, then the number of evisceration and enucleation in subgroups have not confirmed independency. For the tumor presence, the authors got a chi-square value of 5.4, and the associated P value is at 0.02, then the number of validated/nonvalidated tumor presence in subgroups confirmed independency.

Conclusions:

The performed enucleations had 98% cases uveal melanoma, 1% of cases of another type of malignancy (lymphoma non-Hodgkin type), and 1% cases with benign tumor. Enucleation is also today most frequently due to malignant intraocular tumors, whereas evisceration if most frequently for the phthisis eye after a trauma or a previous intraocular surgery. In our study in 22 years interval also in the second period, there was an increased trend of enucleation due to intraocular malignancy. It can have many reasons, especially, that patients are sent to oncology centers late in the advanced stage of tumor.

The possibilities of using the effects of ozone therapy in neurology

OBJECTIVES

The beneficial effects of ozone therapy consist mainly of the promotion of blood circulation: peripheral and central ischemia, immunomodulatory effect, energy boost, regenerative and reparative properties, and correction of chronic oxidative stress. Ozone therapy increases interest in new neuroprotective strategies that may represent therapeutic targets for minimizing the effects of oxidative stress.

METHODS

The overview examines the latest literature in neurological pathologies treated with ozone therapy as well as our own experience with ozone therapy. The effectiveness of treatments is connected to the ability of ozone therapy to reactivate the antioxidant system to address oxidative stress for chronic neurodegenerative diseases, strokes, and other pathologies. Application options include large and small autohemotherapy, intramuscular application, intra-articular, intradiscal, paravertebral and epidural, non-invasive rectal, transdermal, mucosal, or ozonated oils and ointments. The combination of different types of ozone therapy stimulates the benefits of the effects of ozone.

RESULTS

Clinical studies on O2-O3 therapy have been shown to be efficient in the treatment of neurological degenerative disorders, multiple sclerosis, cardiovascular, peripheral vascular, orthopedic, gastrointestinal and genitourinary pathologies, fibromyalgia, skin diseases/wound healing, diabetes/ulcers, infectious diseases, and lung diseases, including the pandemic disease caused by the COVID-19 coronavirus.

CONCLUSION

Ozone therapy is a relatively fast administration of ozone gas. When the correct dose is administered, no side effects occur. Further clinical and experimental studies will be needed to determine the optimal administration schedule and to evaluate the combination of ozone therapy with other therapies to increase the effectiveness of treatment.

Possible consequences of Covid-19 on the nervous system

OBJECTIVES

The aim of the survey was to find out what the possible consequences are of the COVID-19 disease on the nervous system and to propose a method of using artificial intelligence.

MATERIAL AND METHODS

Recent research has shown that the risks to patients due to severe acute coronavirus 2 respiratory syndrome (SARS-COV-2) differ most significantly depending on age and the presence of underlying comorbidities such as: cardiovascular disease, hypertension, diabetes and others. The consequences of COVID-19 on the nervous system are especially important. We performed a detailed selection of articles describing the effects of COVID-19 on the nervous system.

RESULTS

We made a clear summary of the main consequences of COVID-19 on the nervous system and suggested a way to use artificial intelligence.

CONCLUSION

We confirmed research that artificial intelligence methods have the potential to accelerate prediction, especially for the possible consequences of COVID-19 on the nervous system.

Combined methods of rehabilitation of patients after stroke: virtual reality and traditional approach

OBJECTIVES

The aim of the research was to verify the possibilities of using virtual reality in combination with classical approaches to the rehabilitation of patients after stroke.

MATERIAL AND METHODS

As part of rehabilitation, we examined the possibilities of rehabilitation of the upper, lower limbs and fine mobility of the upper limbs in a selected group of patients that met the criteria for inclusion in a combined rehabilitation program using virtual reality with a focus on testing different approaches, devices and applications. At the same time, we tried to identify quantitative and qualitative parameters that could be objectively measured and based on them to evaluate the progress of patients in rehabilitation or in personalizing individual rehabilitation scenarios.

RESULTS

In patients who underwent a combined method of rehabilitation, we observed progress in the development of their ability to improve motor skills. We identified various categories of parameters that can be evaluated by artificial intelligence methods, and we also identified that the key elements in the use of virtual reality as a rehabilitation method are the so-called "WOW" effect and the creation of an emotional change in the patient that motivates him to rehabilitate.

CONCLUSION

We have shown that virtual reality methods have the potential to accelerate rehabilitation and increase the motivation of selected groups of patients after stroke.

Uveal melanoma survival rates after single dose stereotactic radiosurgery

This paper presents the long-term results of single dose stereotactic radiosurgery for intraocular uveal malignant melanoma, and summarizes the results of the retrospective study in 170 Slovak patients. A group of uveal melanoma patients (149 choroidal melanoma, 21 ciliary body melanoma) from 20 to 92 years of age with 59 year median were treated in 2001-2016. There were 81males (47.7%) and 89 females 89 (52.3%). The median overall follow-up time was three years. The median tumor volume at baseline was 0.5 cm³ (ranging from 0.2 to 1.6 cm³). The therapeutic dose was 35.0 Gy by 99% of dose volume histogram. The survival after single dose stereotactic radiosurgery was 96% in one year, 93% in two years, 84% in five years, 80% in seven years and 52% in eleven years. Secondary enucleation was necessary for 22 patients because of secondary glaucoma complication. The enucleation free interval ranged from one to six years. The survival rates in five year intervals and necessity of secondary enucleation due to complications after single dose stereotactic radiosurgery is comparable to other techniques.

Early experiences of planning stereotactic radiosurgery using 3D printed models of eyes with uveal melanomas

OBJECTIVE

The objective of this study was to determine the use of 3D printed model of an eye with intraocular tumor for linear accelerator-based stereotactic radiosurgery.

METHODS

The software for segmentation (3D Slicer) created virtual 3D model of eye globe with tumorous mass based on tissue density from computed tomography and magnetic resonance imaging data. A virtual model was then processed in the slicing software (Simplify3D^®) and printed on 3D printer using fused deposition modeling technology. The material that was used for printing was polylactic acid.

RESULTS

In 2015, stereotactic planning scheme was optimized with the help of 3D printed model of the patient's eye with intraocular tumor. In the period 2001-2015, a group of 150 patients with uveal melanoma (139 choroidal melanoma and 11 ciliary body melanoma) were treated. The median tumor volume was 0.5 cm³ (0.2-1.6 cm³). The radiation dose was 35.0 Gy by 99% of dose volume histogram.

CONCLUSION

The 3D printed model of eye with tumor was helpful in planning the process to achieve the optimal scheme for irradiation which requires high accuracy of defining the targeted tumor mass and critical structures.

Is it sufficient to repeat LINEAR accelerator stereotactic radiosurgery in choroidal melanoma?

OBJECTIVES

One day session LINAC based stereotactic radiosurgery (SRS) at LINAC accelerator is a method of "conservative" attitude to treat the intraocular malignant uveal melanoma.

METHODS

We used model Clinac 600 C/D Varian (system Aria, planning system Corvus version 6.2 verification IMRT OmniPro) with 6 MeV X by rigid immobilization of the eye to the Leibinger frame. The stereotactic treatment planning after fusion of CT and MRI was optimized according to the critical structures (lens, optic nerve, also lens and optic nerve at the contralateral side, chiasm). The first plan was compared and the best plan was applied for therapy at C LINAC accelerator. The planned therapeutic dose was 35.0 Gy by 99 % of DVH (dose volume histogram).

RESULTS

In our clinical study in the group of 125 patients with posterior uveal melanoma treated with SRS, in 2 patients (1.6 %) was repeated SRS indicated. Patient age of the whole group ranged from 25 to 81 years with a median of 54 TD was 35.0 Gy. In 2 patients after 5 year interval after stereotactic radiosurgery for uveal melanoma stage T1, the tumor volume increased to 50 % of the primary tumor volume and repeated SRS was necessary.

CONCLUSION

To find out the changes in melanoma characteristics after SRS in long term interval after irradiation is necessary to follow up the patient by an ophthalmologist regularly. One step LINAC based stereotactic radiosurgery with a single dose 35.0 Gy is one of treatment options to treat T1 to T3 stage posterior uveal melanoma and to preserve the eye globe. In some cases it is possible to repeat the SRS after more than 5 year interval (Fig. 8, Ref. 23).

Stereotactic radiosurgery in intraocular malignant melanoma--retrospective study

OBJECTIVE

One day session linear accelerator based stereotactic radiosurgery of intraocular malignant melanoma is a method of "conservative" attitude to treat posterior uveal melanoma.

MATERIAL AND METHODS

Retrospective clinic-based study of patients with posterior uveal melanoma in stage T2/T3 who underwent stereotactic radiosurgery at linear accelerator in period 2001-2011. Immobilization of the affected eye was achieved by mechanical fixation to the stereotactic Leibinger frame. The stereotactic treatment planning after fusion of computed tomography and magnetic resonance imaging was optimized according to the critical structures (lenses, optic nerves, chiasm).

RESULTS

In group of 96 patients with posterior uveal melanoma treated with one day session stereotactic radiosurgery, patient age ranged from 25 to 80 years with a median of 54 years. Median tumor volume at baseline was 0.6 cm(3) (with range from 0.2 to 1.0 cm(3)). Median maximal dose applied was 49.0 Gy (range from 37.0 to 52.0 Gy). Secondary enucleation was necessary in 11 patients (11.5%) due to complications like irradiation neuropathy and secondary glaucoma. Tumor local control was successful in 95% of patients in 3 years interval after stereotactic radiosurgery and in 85% of patients in 5 years interval after stereotactic radiosurgery.

CONCLUSION

One step LINAC based stereotactic radiosurgery with a single dose 35.0 Gy is one of treatment options to treat T2 or T3 stage posterior uveal melanoma.

[Choroidal melanoma stage T1 - comparison of the planning protocol for stereotactic radiosurgery and proton beam irradiation]

OBJECTIVE

Comparison of two methods of irradiation of patients with malignant choroidal melanoma - stereotactic radiosurgery and proton beam irradiation. External (non-contact) applied irradiation is used as a source of accelerated protons, respectively helium ions. This method allows applications of ionizing irradiation also despite the low radiosensitivity of cells of malignant melanoma of the uvea (MMU). External source of ionizing radiation is modulated current energy electrons, protons or neutrons, accelerated in linear accelerators. From the external medium voltages resources (4-16 MeV) are irradiated tissues with target dose of 5.0-24.0 Gy. Volume protons permeate straight the structures of the eye to a certain distance. The use of proton radiation density of ionized protons increases in the vicinity of the impact due to energy losses for electrons interacting with the environment. At the end of the track there is a huge increase in the ionization dose ("Bragg spike"). Therefore, the structures surrounding the eye at the point of entry and little affected and increasing the dose at the end of the proton beam is ideal for the desired therapeutic effect. Fractionated application is also possible.

CASE REPORT

In December 2011 we performed stereotactic radiosurgery to treat female patient (born 1939) with malignant melanoma of the choroid stage T1 N0 M0. Plan has been drawn up for stereotactic irradiation - model for linear accelerator Clinac, Corvus planning system ver. 6.2, verification and OmniPro IMRT planning system Liebinger ver. 4.3. Patient characteristics were compared with the virtual plan for proton radiation therapy, and we used the scheme in Physical parameters FIAN-technical center in the Russian Federation. We compared both planning protocols and assess in particular the extent of radiation surrounding non-tumor tissue.

RESULTS

When comparing the two planning schemes irradiation levels of surrounding tissues and risk structures (lens, optic nerve, chiasm) in both methods were corresponding to the required standard.

CONCLUSION

Treatment of uveal melanoma through proton beam irradiation in Slovakia is not available yet, although it has several advantages, such as fractionation and the possibility of achieving a higher dose of irradiation to deposit (more than 50.0 Gy). The fundamental difference between the two methods for an eye is particularly the possibility of proton beam irradiation exposure of tumor of iris and ciliary body, which can not be solved through stereotactic radiosurgery. The dose to the tumor during irradiation can be optimized. The model device allowed us to make OPTMI - Therapy (Proton Treatment with Optimized Modulated Intensity).

No differences in outcome between radical surgical treatment (enucleation) and stereotactic radiosurgery in patients with posterior uveal melanoma

To report the treatment outcome and possible survival difference between radical surgical treatment (enucleation) or stereotactic radiosurgery (SRS). LINAC stereotactic radiosurgery is an alternative treatment for posterior uveal melanoma used in Slovakia since 1999. The study analyzed patients treated for posterior uveal melanoma in the period 2001-2008. The aim of the study was to compare the relapse-free survival in the cohort of patients primarily treated with surgery (enucleation) or SRS. A total number of 84 patients were included, treatment was determined on a case-by-case basis. We reviewed the records of patients with ciliary body or choroidal melanoma treated by enucleation - 44 patients (52%) and SRS - 40 patients (48%). The therapeutic attitude was established on the basis of ophthalmoscopy, ultrasound (A, B mode), other ophthalmological findings, visual acuity, and general status of each patient. Volume of the tumor was calculated using the formula: "pi/6 x length x width x height" for each patient. All of the patients before decision to "conservative" attitude therapy underwent MRI examination. The therapeutic dose in SRS patients group was 35.0-38.0 Gy. The data were analyzed using Kaplan - Meier survival method for the differences in survival rates between the treatment groups, and afterwards by Cox s proportional hazard method with predictors involved. Among the baseline covariates evaluated, only age affected the prognosis for survival to a statistically important, however not significant degree. The risk of death among patients treated with enucleation relative to those treated with stereotaxy after adjustment for baseline characteristics of patients, age, and tumor volumes was not significant [1.82] (95% CI, 0.46 to 7.30; P = 0.396). The overall five-year survival rate for patients with posterior uveal melanoma was 72%. Treatment by either primary enucleation or SRS according to our results does not appear to influence the development of metastases in patients with uveal melanoma; the survival prognosis is essentially determined by the stage and character of the tumor. No survival difference attributable to stereotactic irradiation of uveal melanoma has been demonstrated in this retrospective study. A small difference is possible, but a clinically meaningful difference in mortality rates, whether from all causes or from metastatic melanoma, is unlikely. Treatment by either radical surgical attitude (enucleation) or "conservative" LINAC- SRS does not appear to influence the survival rate in patients with uveal melanoma.

Comparison of postsurgical and community acquired bacterial meningitis--analysis of 372 cases within a nationwide survey

The aim of this study was to assess if differences in etiology and risk factors among 372 cases of bacterial meningitis acquired after surgery (PM) or in community (CBM) have impact on outcome of infected patients. Among 372 cases of bacterial meningitis within last 17 years from 10 major Slovak hospitals, 171 were PM and 201 CBM. Etiology, risk factors such as underlying disease, cancer, diabetes alcoholism, surgery, VLBW, ENT infections, trauma, sepsis were recorded and mortality, survival with sequellae, therapy failure were compared in both groups. Significant differences in etiology and risk factors between both groups were reported. Those after neurosurgery had more frequently Coagulase negative staphylococci (p<0.001), Enterobacteriaceae (p=0.01) and Acinetobacter baumannii (p=0.0008) isolated from CSF and vice versa Streptococcus pneumoniae (p<0.001), Neisseria meningitis (p<0.001) and Haemophillus influenza (p=0.0009) were more commonly isolated from CSF in CBM. Neurosurgery (p<0.001), sepsis (p=0.006), VLBW neonates (p=0.00002) and cancer (p=0.0007) were more common in PM and alcohol abuse (p<0.001) as well as otitis/sinusitis (p<0.001) and Roma ethnic group (p=0.001) in CAM. Initial treatment success was significantly more frequently observed among CAM (p<0.001) but cure after modification was more common in PM (p=0.002). Therefore outcome in both groups was similar (14.6% vs. 12.4%, p=NS).

Bacterial meningitis after sinusitis and otitis media: ear, nose, throat infections are still the commonest risk factors for the community acquired meningitis

We investigated how many cases of bacterial meningitis in our national survey were associated with sinusitis or otitis media. Among 372 cases of bacterial meningitis within our nationwide 17 years survey, 201 cases were community acquired (CBM) and in 40 (20%) otitis media or sinusitis acuta/chronica were reported 1-5 weeks before onset of CBM. Diabetes mellitus (20% vs. 7.5%, p=0.01), alcohol abuse (35% vs. 15.4%, p=0.003) and trauma (30% vs. 14.9%, p=0.02) were significantly associated with CBM after ENT infections. Concerning etiology, CBM after sinusitis/otitis was insignificantly associated with pneumococcal etiology (50% vs. 33.8 %, NS) and significantly associated with other (L. monocytogenes, Str. agalactiae) bacterial agents (9.9 % vs. 25 %, p=0.008) . However those significant differences for new ENT related CBM had no impact on mortality (12.4 % vs. 5%, NS), failure after initial antibiotics (10 % vs. 9.5%, NS) and neurologic sequellae (12.5 % vs. 15.4 %, NS).

Bacterial meningitis after craniocerebral trauma in the community

Craniocerebral trauma is one of major risk factors for development of meningitis. We reviewed 30 cases of bacterial meningitis occurring in community after craniocerebral trauma. Alcohol abuse was significant risk factor occurring in trauma patients with meningitis present in 50% in our cohort (p=0.0001). The most common pathogen in posttraumatic meningitis was Str. pneumoniae (90% vs. 33.8%, p=0.0001). However mortality was very low, only 5% probably because of early diagnosis and treatment of patients at risk for bacterial meningitis but neurologic sequellea were significantly more common (p=0.00001) in patients after craniocerebral trauma.

Predictors of inferior outcome in community acquired bacterial meningitis

The aim of this study was to assess mortality and sequellae within cases from Nationwide survey of community acquired meningitis and identify risk factors for inferior outcome. Risk factors such as underlying disease (diabetes mellitus, cancer, trauma, neonatal age, splenectomy, alcoholism, sepsis, other infections), etiology, clinical symptoms and outcome (death, improvement and cured after modifications of ATB therapy, cured without change of therapy, cured with neurologic sequellae) were recorded and analysed with univariate analysis (chi2 or t test for trends, CDC Atlanta 2004). Analysing risk factors for inferior outcome (death or cured with neurologic sequellae), we compared patients who died or survived with neurologic sequellae to all patients with community acquired bacterial meningitis. Univariate analysis showed that trauma (p<0.05), alcohol abuse (p<0.05), diabetes, S. aureus (p<0.05) and gram-negative etiology (A. baumannii, Ps. aeruginosa or Enterobacteriaceae) (36% vs. 11,9%, p<0.05) were predicting inferior outcome. Analysing risk factors for treatment failure (death or failed but cured after change of antibiotic treatment) prior sepsis (34.1% vs. 13.9%, p<0.01) and gram-negative etiology (25% vs. 11.9%, p<0.02) were statistically significant predictors of treatment failure. Neisseria meningitis had less failures (p<0.05). Concerning infection associated mortality again diabetes mellitus (p<0.05), alcoholism (p<0.05) staphylococcal and gram-negative etiology (p<0.05) were significant predictors of death. N. meningitis had surprisingly less treatment failures (appropriate and rapid initial therapy). Neurologic sequellae were more common in patients with alcohol abuse (p<0.05), craniocerbral trauma (p<0.05) and less common in meningitis with pneumococcal etiology (p<0.05).

Infectious embolisation to the central nervous system from endocarditis: analyses of 99 cases

Within a cohort of 606 cases of infective endocarditis, 263 were complicated and 99 embolizing, of them 32 to the central nervous system (CNS). Significant predictors of CNS embolisation were inappropriate therapy (p<0.01) and enterococcal etiology (p<0.01). Mortality in patients with CNS emboli was 65% what was significantly higher than in cases without embolisation - 15% (p<0.01).

Is combination therapy with betalactam plus aminoglycoside (AGL) improving the outcome of nosocomial meningitis in children?

We have been unable to document a benefit of a combination of aminoglycosides with betalactam or carbapenem antibiotics in nosocomial meningitis. This was similar to the cases of sepsis, where survival of patients did not improve with combination therapy. Combination therapy did not increase the chance of appropriateness of the therapy. 30% of those on combination therapy were considered as inappropriately treated in comparison to 2.8% of those on monotherapy (p<0.01).

National 14 years survey of 171 cases nosocomial meningitis in children and comparison of two periods 1993-1998 to 1999-2006

In 1993-1998 and in 1999-2004 we have performed two surveys of pediatric bacterial meningitis in all 8 neurosurgery/pediatrics and infectious diseases departments in Slovakia. We have detected 101 and another 54 cases with attributable mortality of 15% and sequellae in 18%.

Postsurgical meningitis caused by Acinetobacter baumannii associated with high mortality

Twenty five (25) cases of nosocomial postsurgical meningitis due to Acinetobacter baumannii meningitis were compared to other 146 cases of meningitis after surgery caused by other pathogens. Prior neurosurgical ventriculo-peritoneal shunt insertion and CNS abnormality as well as very low birth weight were significant risk factors for acquisition of Acinetobacter baumannii meningitis. Mortality - 40% among children with nosocomial meningitis was unacceptably high and significantly higher than among meningitis caused by microorganisms other than Acinetobacter baumannii.

Neuroinfections complicating foreign body implants after perinatal trauma or meningitis in 60 children

Meningitis after artificial implants in 60 children, mainly after foreign body infections (FBI) was caused more frequently by coagulase negative staphylococci and Ps. aeruginosa than other organisms and was significantly associated with perinatal trauma, hydrocephalus, haemorrhage or VLBW and had more neurologic sequels despite mortality was similar to other nosocomial meningitis.

Complications in patients with uveal melanoma after stereotactic radiosurgery and brachytherapy

Malignant uveal melanoma is the most common intraocular tumour with the incidence about 0.7-1.0 in 100.000 inhabitants. Enucleation is still a standard treatment method for posterior uveal melanoma, but conservative methods are an adequate alternative. Brachytherapy has been used more than 20 years in our Department, stereotactic radiosurgery was introduced in 1999. In years 1991-2004, 145 patients with uveal melanoma were treated at the Department of Ophthalmology, Comenius University, Bratislava. Conservative treatment/brachytherapy is indicated in tumours staged T1-T3. Survival is comparable for all conservative methods. After stereotactic radiosurgery (Linac), the necessity of enucleation because of complications (e.g. secondary glaucoma), after brachytherapy (Ru106 plaques), it was 5%. Conservative methods and combined techniques are effective methods for the therapy of uveal melanomas (Fig. 5, Tab. 1, Ref. 6).

Electrophysiological effects and clinical results of direct brain stimulation for intractable epilepsy

OBJECTIVE

Epilepsy can be considered as a result of the imbalance of the excitatory and inhibitory processes. Therefore, the artificial enhancement of the activity of brain inhibitory mechanisms might lead to a beneficial therapeutic effect for intractable epilepsy patients.

MATERIAL AND METHODS

Studies of the inhibitory effects of electrical stimulation of the head of the caudate nucleus (HCN), cerebellar dentate nucleus (CDN), thalamic centromedian nucleus (CM), and neocortical and temporal lobe mesiobasal epileptic foci were performed on 150 patients with implanted intracerebral electrodes. Chronic brain stimulation with implanted neurostimulators was performed on 54 patients. Sixteen were followed up to 1.5 years (mean 1.2 years).

RESULTS

The study demonstrated that 4-8 Hz HCN and 50-100 Hz CDN stimulation suppressed the subclinical epileptic discharges and reduced the frequency of generalized, complex partial, and secondary generalized seizures. CM stimulation (20-130 Hz) desynchronized the EEG and suppressed partial motor seizures. Direct subthreshold 1-3 Hz stimulation of the epileptic focus may suppress rhythmic afterdischarges (ADs). Seizures were eliminated for 26 of 54 patients (48%), worthwhile improvement was achieved for 23 of 54 patients (43%), and no improvement was observed in 5 of 54 patients (9%).

CONCLUSION

The artificial increase of the activity of brain inhibitory system may suppress the activity of epileptic foci, and, in long run, stabilize this epileptic foci activity at a lower, perhaps normal, level. Therapeutic direct brain stimulation, therefore, might serve as a useful tool in the treatment of intractable and multifocal epilepsy, and might be combined with ablative surgical methods.

Computerized brain atlas in functional neurosurgery

Computerized brain atlas is a new application area in the practical use of stereotactic neurosurgery. Our approach provides a solution for the straightforward definition of a coordinate system (CA-CP), localization of the selected target point, trepanation points and trajectory transformation of the stereotactic electrode or canula for functional neurosurgery. These problems were solved by comparison of CT, MR and the Schaltenbrand-Wahren atlas. Our original software package integrates all modalities into one system.

Combination warp-matching method for stereotactic neurosurgery

Digital image warping is a growing branch of image processing that deals with geometric transformation techniques. A geometric transformation is an operating that redefines the spatial relationship between points in an image. Physically based modeling is a field strongly attracting research interest in recent years. A physically based model includes physical characteristics of things being modeled and specifies their behavior via mathematical equations. This paper presents a warp-matching method and a general non-rigid body representation suitable for physically based modeling of deformations of heterogeneous objects. The main aim is to develop a new heterogeneous warping technique to correct for distortion in medical data sets.

Mathematical methods using CT and MR images for stereotactic neurosurgery

A new application area in the practical usage of magnetic resonance imaging (MRI) has been identified as a methodology of stereotactic operation. In particular, our approach provides a solution for the straightforward definition of target and trepanation points for the purposes of stereotactic neurosurgical operation, and an exact testing of its result. The definition of the proper transformation between different examination data sets is a crucial mathematical problem. This is well done by morphing and the thin plate spline method.

MR-guided stereotaxy in functional neurosurgery

MR imaging enables the localization of the anteroposterior commissural line, but sometimes it is difficult to define the anterior commissure point. The corpus callosum is more easily identified in this case. We performed an MR imaging using the following methodology; a single transverse scan from which a coronal scan is planned with compensation. A sagittal scan is prescribed from the coronal slice, compensating for any misalignment of patient position. Finally the scan series are prescribed from the sagittal scan, following which we calculate MR distortion. This methodology was used for functional stereotaxy, and the results correlated well with the classical method.

[CT and MR imaging in stereotaxic neurosurgery]

The combination of CT and MR examinations indicates a specific approach to the treatment of brain mass lesions. CT guided stereotaxy is sufficient for well demarcated tumors, haemorrhages and abscesses. MR guided stereotaxy is necessary to be performed in invasively growing brain tumors where explicit histological verification and localisation must be ascertained. In addition it is necessary to take into account the image deformation due to the stereotactic ring. In functional neurosurgery the MR examination visualises the anatomical structures which are needed for the ascertainment of coordinate systems landmarks in coordinate system. (Fig. 1, Tab. 1, Ref. 5.).

Transformation of computed tomography and magnetic resonance images

This paper discusses the transformation of computed tomography (CT) and magnetic resonance (MR) images, which maps the stereotactic volumetric cube of one examination to another. There are some mathematical problems connected with the present method. This approach provides a better visual detection and localization of the target point for the neurosurgeon or radiologist.

[The legal and ethical aspects of nerve tissue transplantation]

The authors have specified the following criteria for the withdrawal of embryonal tissue at their department: 1) only tissue from dead fetus is allowed to be used in neurotransplantation; 2) embryonal tissue is to be obtained after spontaneous abortions from volunteers or from women asking for artificial abortion; 3) the women should be informed about the curative purposes of embryonal tissue voluntary donorship and they must give a written consent; 4) decision on abortion should be separated from the use of embryonal tissue; 5) women should not know recipients; no payments should be made for tissue; 6) the donor is not permitted to impregnate in order to use embryos for research or clinical purposes; 7) sampling of BWR, HBsAG, anti-HIV, cytomegalovirus, herpes I and II is to be made for serologic examinations and that from the cervix for cultivation and sensitivity, as well as ultrasound verification of a germinal age is done in potential donors; 8) consent should be signed to embryonal brain transplantation by recipient or his legitimate deputy if the recipient is certifiable. The above criteria should protect both the donor and the recipient. The use of embryonal tissue cultures seems to be promising. In addition to legal and ethic problems, immunological problems and problems concerning the aseptic withdrawal of embryonal tissue are falling off.

[Long-term results in patients with stereotaxic surgery for psychopathologic disorders]

Long-term results (5-20 years) recorded in 304 patients operated on stereotactically for psychopathologic disorders are presented. The largest group of 260 surgically treated subjects represented aggressive patients. This group consisted of 150 patients with mental retardation, 70 with epilepsy, 20 with schizophrenia, and 20 patients with sexual deviations. Amygdalectomy for patients with normal intellect and posterior hypothalamotomy for those with reduced intellect proved to be the most effective procedure. Symmetrical operations were also effective. In some cases a combination of two target was necessary. In epileptics with aggressivity the combination of amygdalectomy and hippocampectomy yielded the best results. In aggressivity with sexual deviations anterior hypothalamotomy was the most effective operation. Favorable results in aggressivity therapy were recorded in 60% of patients. In patients with criminal sexual deviations, in drug addicts, and in alcoholics, anterior hypothalamotomy was found to be most effective, with favorable results in 50% of patients. In patients with depression, thalamotomy or stimulation of the limbic regions of the thalamus decreased the depression, with favorable results recorded in 66% of patients. The results of the surgically treated patients show that target-oriented stereotactic operations remove psychopathologic symptoms, improve the effectiveness of psychoactive drugs and the social adaptability of patients. (Ref. 15.)

Stereotactic technique and pathophysiological mechanisms of neurotransplantation in Huntington's chorea

In Huntington's chorea, embryonal brain tissue (striatum) was implanted in the caudate nucleus bilaterally, using stereotaxy assisted by CT. A special cannula allowed the placement into the brain of 3 or 4 grafts of embryonal tissue along the determined trajectory by one introduction of the cannula. The pathophysiological mechanism of neurotransplantation in Huntington's chorea is to compensate for the degenerated striatal tissue by embryonal striatum, so it is necessary to supply a quantity of embryonal striatal tissue which enables the whole functional integrity. Therefore, we use material from several embryos.

Clinical experience in intraoperational determination of brain inhibitory structures and application of implanted neurostimulators in epilepsy

Therapeutic brain stimulation was applied in 74 patients with resistant forms of epilepsy. It was shown that low frequency stimulation of certain zones of the head of the caudate nucleus and higher frequency stimulation of the dentate nucleus of the cerebellum lead to a marked suppression of interparoxysmal epileptic activity and to a disruption of both focal and generalized epileptic discharges. It is necessary to determine, by means of stereo-electroencephalography, the variability for localizing the inhibitory zones of the structures to implant the neurostimulators exactly.

Pathophysiological mechanisms and results of stereotactic treatment of generalized epilepsy

The paper describes pathophysiological mechanisms and analyzes the results of surgical treatment of severe forms of drug-resistant generalized epilepsy in 150 patients who underwent surgery at the departments of stereotactic and functional neurosurgery in Tbilisi and Bratislava. The epileptic system of all patients was localized stereoelectroencephalographically (SEEG) by recording spontaneous activity or evoked aparoxysms. SEEG examination indicate that pacemakers of epileptic activity are most frequently localized in the mediobasal structures of the temporal lobes. The long-term results of stereotactic treatment of generalized forms of epilepsy show recovery in 50% of patients and marked improvement in 30%. An individually determined strategy of surgical procedures is the main principle of surgical treatment of severe drug-resistant forms of epilepsy. Depending on indications it can include resection of the cortex or lobes of the brain, single or repeated stereotactic destructions of the pacemaker structures of the epileptic system and the pathways of spread of the spasm discharge, as well as therapeutic electrostimulation of the brain inhibitory systems.

Herpes simplex virus DNA in the brain of psychotic patients

Herpes simplex virus (HSV) DNA was found by spot blot hybridization in the right nc. amygdalae of 3 out 10 patients who underwent curative stereotactic surgery for severe mental retardation with aggressive behavior and/or paranoic schizophrenia. Of these, 6 were also tested for the presence of CMV DNA sequences with negative results. Biopsy specimens from nc. amygdalae of another 7 psychotic patients were cultured in vitro but no virus was isolated.

Central stimulation treatment of epilepsy

Therapeutic electrical stimulation of nucleus caudatus was performed in 26 patients suffering from epilepsy. Sixteen of them had previously undergone destructive stereotactic surgery in different deep brain structures and the stimulation was indicated as an additional procedure. The results reported are related to 10 patients stimulated without any other surgical treatment. In 3 subjects stimulation of temporal lobe structures was performed as well. Good therapeutic effects were obtained in 2 cases following caudate stimulation. Mild improvement or no effect were obtained in the other cases, including the two submitted to hippocampal stimulation. Interesting speculation on the relationships between caudate and hippocampal electrical activity have been generated.

Combined transtentorial dentatotomy with pulvinarotomy in cerebral palsy

For frequently associated spasticity with involuntary movements in cerebral palsy operations on cerebellar nuclei or on the pulvinar of the thalamus are recommended. We combined both approaches in 45 patients. The combination was possible after experiences with transtentorial dentatotomy, in which the electrodes are introduced into the deep structures of the cerebellum from a burr-hole on the lambdoid suture. The same lambdoid approach may equally well be applied for introducing electrodes into the pulvinar of the thalamus. The lesion in the pulvinar may moreover be combined with the target in the centrum medianum or in the nuclei VIM-VCP or VOP. Lesions are always asymmetric and multilocular. Their influence on the clinical picture is quite favourable.