The dual effect of vagus nerve stimulation in pediatric patients with drug-resistant epilepsy: Is there more than seizure control?

This is a retrospective and comparative pilot study to investigate the role of vagus nerve stimulation (VNS) in improving cognitive functions in the pediatric age group with drug resistant epilepsy (DRE). It was conducted from January 2018 to February 2023. Children between the ages of 4 and 18 years were divided into two groups, the "VNS group" and the "best medical treatment (BMT) group". Follow up period was 12 months. Demographic, clinical, etiological and investigational data were recorded. Cognitive assessment using the Modified Mini-Mental State Examination for children (MMSE) was recorded at baseline and 12 months later for each group. 76.4 % of patients were classified as epilepsy secondary to cerebral palsy. 75 % of patients showed ≥ 50 % seizure frequency reduction among the VNS group as compared to 12.5 % in the BMT group. None of both groups achieved seizure freedom. At 12 months, both BMT and VNS groups showed statistically significantly improved overall cognitive score from baseline records (p = 0.027) and (p = 0.012), respectively, with a significantly higher improvement in VNS group. Also, statistical sub-analysis of cognitive subscales in cerebral palsy patients in both groups was conducted and revealed a significant improvement (p = 0.02) in the VNS group. We concluded that there is a potential role of VNS in improving cognitive functions which was shown by using a cost-effective screening tool. A significant effect was observed specially in cerebral palsy patients. This is very beneficial in limited-resources countries since VNS has good safety profile, high seizure control, and added value to cognitive functions.

Surgery for Obsessive-Compulsive Disorder and Transient Tremors as Newly Reported Side Effect: First Psychiatric Neurosurgery in Egypt.

Introduction: The use of surgery for treatment of psychiatric conditions is a well-established strategy, especially in severe and resistant obsessive-compulsive disorder. Attractive anatomical and functional targets for stereotactic surgery are reported in some studies. Surgery for treatment of psychiatric conditions in our nation and Arab world is obscured and hidden because of several social and cultural limitations, which should be overcome. We report here the first psychiatric neurosurgery in our nation and how we overcome such community limitation. This the first report of postoperative tremor. Case Presentation: Young patient presented with severe and persistent obsessive-compulsive disorder resistant to all non-surgical modalities for several years. Stereotactic ablation surgery was done under local anaesthesia. Marked improvement in our obsessive-compulsive disorder patient after psychiatric neurosurgery with self-limited tremor was not reported before in the literature. The medications were the same before and immediate after surgery and this is not a drug-induced tremor. Postoperative YBOCS showed 90% of improvement. Conclusion: Surgery-induced tremor could be a self-limited side effect after surgery in obsessive-compulsive disorder. Safety and efficacy should be promoted in our nation and Arab world. Society and cultural limitations should be overcome by further research studies, intervention, and activism in the field of mental health systems in our nation and Arab countries to improve awareness.

Consensus Guideline on the Management of Epilepsy in Egypt: A National Delphi Consensus Study.

OBJECTIVE: In epilepsy, early diagnosis, accurate determination of epilepsy type, proper selection of antiseizure medication, and monitoring are all essential. However, despite recent therapeutic advances and conceptual reconsiderations in the classification and management of epilepsy, serious gaps are still encountered in day-to-day practice in Egypt as well as several other resource-limited countries. Premature mortality, poor quality of life, socio-economic burden, cognitive problems, poor treatment outcomes, and comorbidities are major challenges that require urgent actions to be implemented at all levels. In recognition of this, a group of Egyptian epilepsy experts met through a series of consecutive meetings to specify the main concepts concerning the diagnosis and management of epilepsy, with the ultimate goal of establishing a nationwide Egyptian consensus. METHODS: The consensus was developed through a modified Delphi methodology. A thorough review of the most recent relevant literature and international guidelines was performed to evaluate their applicability to the Egyptian situation. Afterward, several remote and live rounds were scheduled to reach a final agreement for all listed statements. RESULTS: Of 278 statements reviewed in the first round, 256 achieved ≥80% agreement. Live discussion and refinement of the 22 statements that did not reach consensus during the first round took place, followed by final live voting then consensus was achieved for all remaining statements. SIGNIFICANCE: With the implementation of these unified recommendations, we believe this will bring about substantial improvements in both the quality of care and treatment outcomes for persons with epilepsy in Egypt. PLAIN LANGUAGE SUMMARY: This work represents the efforts of a group of medical experts to reach an agreement on the best medical practice related to people with epilepsy based on previously published recommendations while taking into consideration applicable options in resource-limited countries. The publication of this document is expected to minimize many malpractice issues and pave the way for better healthcare services on both individual and governmental levels.

Cost-effectiveness of HARNESS-MRI protocol in focal drug-resistant epilepsy in a limited-resources country: An Egyptian study.

OBJECTIVES: The international league against epilepsy (ILAE) recommended the harmonized neuroimaging of epilepsy structural sequences (HARNESS-MRI) to improve the detection of epileptogenic lesions in patients with focal drug-resistant epilepsy (DRE). The application of this protocol is still limited in low-resource countries, mainly due to apparent high costs. We aimed to evaluate the cost-effectiveness of the HARNESS-MRI protocol in Egypt and highlighted our experience. METHODS: Patients diagnosed with focal DRE at Cairo University epilepsy clinic underwent both conventional MRI (c-MRI) and HARNESS-MRI. Electro-clinical data were collected and analyzed. After the radiologists' initial diagnosis, a multidisciplinary team re-evaluated the MRI. Lesion detection rate and cost for detecting an extra lesion by HARNESS-MRI protocol were calculated. RESULTS: The study included 230 patients with focal DRE (146, 62% males and 91, 38% females), with a mean age of 20.5 years. Epileptogenic lesions detected by c-MRI and HARNESS-MRI before and after the board meeting were 40, 106, and 131 lesions, respectively (P < 0.001). Sixty-nine percent of the lesions detected by HARNESS-MRI were missed on c-MRI; most commonly were mesial temporal sclerosis (MTS) and Malformations of cortical development (MCDs). Thirty-seven MTS and 32 MCDs were detected with HARNESS-MRI, compared to only 6 and 3, respectively, detected on c-MRI (P < 0.001). HARNESS-MR protocol is more cost-effective than c-MRI in detecting MRI lesions; it can save about 42$ for detecting an extra lesion in MRI. CONCLUSION: The HARNESS-MRI protocol was cost-effective and highly recommended even in limited-resource countries for patients with focal DRE.

Resective epilepsy surgery in a limited-resource settings: A cohort from a multi-disciplinary epilepsy team in a developing country.

Background: Multidisciplinary pre-surgical evaluation is vital for epilepsy surgery decision and outcomes. Resective epilepsy surgery with assisted monitoring is currently a standard treatment for focal drug resistant epilepsy (DRE). In resource-limited countries, lack of epilepsy surgery center is a huge challenge. We presented and illustrated how to create a multidisciplinary protocol with resource-limited settings in a developing country and epilepsy surgery outcome using brain mapping and monitoring techniques for ensuring satisfactory resection. Methods: We created multicentric incomplete but complementary units covering all epilepsy-related sub-specialties and covering a wide geographical area in our country. Then, we conducted a prospective and multicentric study with low resource settings on patients with focal DRE, who underwent resective epilepsy surgery and were followed up for at least 12 months and were evaluated for postoperative seizure outcome and complications if present. Preoperative comprehensive clinical, neurophysiological, neuropsychological, and radiological evaluations were performed by multidisciplinary epilepsy team. Intraoperative brain mapping including awake craniotomy and direct stimulation techniques, neurophysiological monitoring, and electrocorticography was carried out during surgical resection. Results: The study included 47 patients (18 females and 29 males) with mean age 20.4 ± 10.02 years. Twenty-two (46.8%) patients were temporal epilepsy while 25 (53.2%) were extra-temporal epilepsy. The epilepsy surgery outcome at the last follow up was Engel Class I (seizure free) in 35 (74.5%), Class II (almost seizure free) in 8 (17%), Class III (worthwhile improvement) in 3 (6.4%), and Class IV (no worthwhile improvement) in 1 patient (2.1%). Conclusion: With low resource settings and lack of single fully equipped epilepsy center, favorable outcomes after resective surgery in patients with focal DRE could be achieved using careful presurgical multidisciplinary selection, especially with using intraoperative brain mapping and electrocorticography techniques.

Functional and oncological outcome of petroclival chondrosarcoma operated on through an extradural anterior petrosectomy approach. A single center experience.

BACKGROUND: Management of skull base chondrosarcoma (SBC) remains challenging due to its deep location and complex growth pattern. Non-total resection and postoperative residual mass are common features, with controversy regarding the need to offer systematic postoperative radiation therapy or additional surgery. METHODS: A single-center retrospective cohort study was conducted on 10 consecutive patients harboring petroclival chondrosarcomas that were operated on between May 2007 and March 2019. After resection, the patients were allocated to a wait-and-rescan policy. RESULTS: Patients were operated on through an extradural anterior petrosectomy (EAP). Subtotal tumor resection was achieved in all patients. The mean duration of follow-up was 70 months (range 25-137/median 67 months). Clinical outcomes dramatically improved in three (30%) patients, while five patients retained preoperative cranial nerve (CN) disturbances after surgery (50%). Two patients reported transient postoperative worsening of their symptoms (20%). All of the postoperative CN new deficits improved within one year, except in one patient who showed permanent facial nerve palsy. The preoperative median Karnofsky Performance Scale (KPS) score was 80 (range 70-100), and then it became 90 (range 70-100) postoperatively. Patients harboring a tumor residue were included in a wait-and-rescan policy. With this regimen, tumor control was obtained in seven patients (70% of cases until the last follow-up). Three patients (30%) showed progression of the residual; two of them were treated with adjuvant therapy, while an extra cranial growth residue was observed in the third. CONCLUSION: Optimal and reasonable surgical resection of petroclival chondrosarcomas could be achieved with good to excellent functional outcomes through an EAP. In spite of a significant percentage of regrowth, only one patient required additional salvage surgery.

Radiosurgical Corpus Callosotomy for Intractable Epilepsy: Retrospective Long-Term Safety and Efficacy Assessment in 19 Patients an Review of the Literature.

BACKGROUND: Some patients suffering from intractable epileptic seizures, particularly drop attacks (DAs), are nonremediable by curative techniques. Palliative procedure carries a significant rate of surgical and neurological complications. OBJECTIVE: To propose evaluation of safety and efficacy of Gamma Knife corpus callosotomy (GK-CC) as an alternative to microsurgical corpus callosotomy. METHODS: This study included retrospective analysis of 19 patients who underwent GK-CC between 2005 and 2017. RESULTS: Of the 19 patients, 13 (68%) had improvement in seizure control and 6 had no significant improvement. Of the 13/19 (68%) with improvement in seizures, 3 (16%) became completely seizure-free, 2 (11%) became free of DA and generalized tonic-clonic but with residual other seizures, 3 (16%) became free of DA only, and 5 (26%) had >50% reduction in frequency of all seizure types. In the 6 (31%) patients with no appreciable improvement, there were residual untreated commissural fibers and incomplete callosotomy rather than failure of Gamma Knife to disconnect. Seven patients showed a transient mild complication (37% of patients, 33% of the procedures). No permanent complication or neurological consequence was observed during the clinical and radiological workup with a mean of 89 (42-181) months, except 1 patient who had no improvement of epilepsy and then aggravation of the pre-existing cognitive and walking difficulties (Lennox-Gastaut). The median time of improvement after GK-CC was 3 (1-6) months. CONCLUSION: Gamma Knife callosotomy is safe and accurate with comparable efficacy to open callosotomy in this cohort of patients with intractable epilepsy suffering from severe drop attacks.

Increased Gray Matter Density in the Right Mesencephalic Tegmentum Is Associated With Better Engel Classes I and II After Radiosurgery for Hypothalamic Hamartomas.

BACKGROUND: Hypothalamic hamartomas (HHs) are disabling congenital lesions, responsible for gelastic seizures frequently associated with catastrophic epilepsies, epileptogenic encephalopathy, and cognitive and psychiatric severe comorbidities. Stereotactic radiosurgery (SRS) is a well-established minimally invasive therapeutic approach. OBJECTIVE: To assess whether pretherapeutic gray matter density (GMD) correlates with seizure outcome. METHODS: We used voxel-based morphometry at whole-brain level, as depicted on pretherapeutic standard structural magnetic resonance neuroimaging. We examined 24 patients (10 male patients, 14 female patients; mean age, 12.7 yr; median, 9; range, 5.9-50) treated in Marseille University Hospital, France, between May 2001 and August 2018. RESULTS: Most relevant anatomic area predicting postoperative Engel classes I and II vs III and IV after SRS for HHs was mesencephalic tegmentum. Higher pretherapeutic GMD in this area was associated with better outcomes for seizure cessation. The only other statistically significant clusters were right cerebellar lobule VIIIb and VIIIa. Lower pretherapeutic GMD in both clusters correlated with better Engel class outcomes. GMD decreased with age in the left mediodorsal thalamus. CONCLUSION: Seizure cessation after SRS for HHs was associated with higher GMD in mesencephalic tegmental area, acknowledged to be involved in the neural control of explosive vocal behavior in animals. This area is connected by the mamillotegmental bundle to the lateral tuberal nucleus area of the hypothalamus, where HHs are known to rise. In the future, the detection of more gray matter in this "laugh" tegmental area based on pretherapeutic routine structural neuroimaging might help in patient selection for minimally invasive radiosurgery for HH.

Is Real-Time Inverse Planning Optimizing Dose to the Normal Brain? A Prospective Comparative Trial in a Series of Brain Metastases Treated by Stereotactic Radiosurgery.

BACKGROUND: Radiosurgery has demonstrated good safety and efficacy in the treatment of multiple brain metastases (BMs). However, multi-target dose planning can be challenging and time-consuming. A recently developed real-time inverse treatment planning (IP) by convex optimization has been demonstrated to produce high-quality treatment plans with good conformity and selectivity in single-target plans. We intended to test the capacity of this IP to rapidly generate efficient plans while optimizing the preservation of normal tissue in multiple BM. METHODS: Seventy-nine patients (mean age 62.4, age range 22-85) with a total of 272 BMs were treated by Gamma Knife Radiosurgery. All subjects were treated using a forward planning (FP) technique by an expert neurosurgeon. The new Intuitive Plan was applied and able to automatically generate an alternative plan for each patient. All planning variables were collected from the IP to be compared with the corresponding measurements obtained from the FP. A paired sample t test was applied to compare the 2 plans for the following variables: brain volumes receiving 10 Gy (V10) (primary endpoint), and 12 Gy (V12), planning indices (selectivity, coverage, gradient, and Paddick Conformity Index [PCI]), beam-on time (BOT), and integral doses. Additionally, the noninferiority margin for each item was calculated, and the 2 plans were compared for noninferiority using a paired t test. RESULTS: The mean age of patients was 62.4 years old (age range 22-85), with a sex ratio of 1.02. The average number of lesions per patient was 3.4 (range 1-12). The mean prescription dose was 21.46 Gy (range 14-24 Gy). Noninferiority of the IP was concluded for V10, V12, prescription isodose volume, BOT, PCI, and selectivity. The V10 (and V12) was significantly lower with the IP (p < 0.001). These volumes were 8.69 cm3 ± 11.39 and 5.47 cm3 ± 7.03, respectively, for the FP and 7.57 cm3 ± 9.44 and 4.78 cm3 ± 5.86 for the IP. Only the coverage was significantly lower with the IP (-2.3%, p < 0.001), but both selectivity (+17%) and PCI (+15%) were significantly higher with the IP than FP (p < 0.001). CONCLUSION: This IP demonstrated its capacity to generate multi-target plans rapidly, with a dose to the brain (V10) and BOT noninferior to the one of a human expert planner. These results would benefit from confirmation in a larger prospective series.

Mask-Based versus Frame-Based Gamma Knife ICON Radiosurgery in Brain Metastases: A Prospective Randomized Trial.

BACKGROUND: Radiosurgery is performed with a diversity of instruments relying usually either on a stereotactic frame or a mask for patient head fixation. Comfort and safety efficacy of the 2 systems have never been rigorously evaluated and compared. MATERIAL AND METHOD: Between February 2016 and January 2017, 58 patients presenting with nonsmall cell lung cancer brain metastases have been treated by Gamma Knife radiosurgery (GKS) with random use of a frame or a mask for fixation were included patients older than 18, with <5 brain metastases (at the exclusion of brainstem and optic pathway's locations) and no earlier history of radiotherapy. The primary outcome measure was the pain scale assessment (PSA) at the beginning of the GKS procedure. RESULTS: The PSA at the beginning of the GKS procedure was not different between the 2 groups. The PSA at the day before GKS, before magnetic resonance imaging, just after frame application, and the day after radiosurgery (departure) has shown no difference between the 2 groups. At the end of the radiosurgery itself (just after frame or mask removal) and 1 h after, the mean pain scale was higher in patients treated with the frame (p < 0.05 and p < 0.001, respectively) but 2 patients were not able to tolerate the mask discomfort and had to be treated with frame. Tumor control and morbidity probability were demonstrated to be no difference between the 2 groups in this population of patients with BM not in highly functional area. The median of the extra dose to the body due to the cone-beam computed tomography was 7.5 mGy with a maximum of 35 mGy in patients treated with a mask fixation (null in the others treated with frame). Mask fixation was associated to longer treatment time although the beam on time was not different between the 2 groups. CONCLUSION: In selected patients, with brain oligo-metastases out of critical location, single-dose mask-based GKS can be done with a comfort and a safety efficacy comparable to frame-based GKS. There seems to be no clear patient data that confirm the value of the mask system with regards to comfort.

Delayed Collet-Sicard syndrome after internal carotid dissection and Jefferson fracture. Case report and Review of Literature.

BACKGROUND: Lower cranial nerve palsies, or Collet-Sicard syndrome, can be caused by many different etiologies including head trauma, basilar occipital fractures, tumors, and interventions. Few reports describe different presentations of this condition, and we present here a case study to increase awareness of and add to the variable spectrum. CASE DESCRIPTION: A 56-year-old who had been hit while diving was admitted to our department. On examination, he was conscious without any signs of lateralization but presented with severe neck pain. CT brain and cervical spine revealed a C1 fracture with bilateral symmetrical fracture of the anterior and posterior arches (Jefferson's fracture) and slight bilateral joint dislocation C1-C2 discreetly predominant on the left. One week later, he presented with dysarthria, dysphonia, swallowing disorder, anisocoria, tongue deviation, and palate deviation (XII, IX, and X). CT Angiography showed dissection of the internal carotid artery immediately after the carotid bulb. He has been treated conservatively with curative anticoagulants with stable symptoms. No surgical intervention had been proposed. CONCLUSION: Adding to the literature, delayed Collet-Sicard syndrome and lower cranial affection can be caused by missed carotid wall hematoma following severe craniocervical trauma associated with Jefferson's fracture.

Epileptic hypothalamic hamartomas impact of topography on clinical presentation and radiosurgical outcome.

INTRODUCTION: Evidence exists for the role of the hypothalamic hamartoma's topography as a determinant for the clinical presentation. How the hamartoma relation to the hypothalamic structures can make clinical presentations, severity and surgery outcomes different from patient to patient is largely unknown. Our aim was to analyze the effect of fine anatomical topography on clinical spectrum and radiosurgery outcome. METHODS: Forty-eight epileptic patients with hypothalamic hamartoma were treated by Gamma Knife Surgery and were reviewed for fine topography and morphology using magnetic resonance neuroimaging. We evaluated different topographic patterns; contact to prominent structures (the mammillary body, tuber cinereum and pituitary stalk), the degree of involvement within sagittally-oriented regions, (mammillary, tuberal, and supra optic) coronally-oriented zones (periventricular, medial, and lateral), lesion dimensions (length, width, and height),and volumes (total, intra-hypothalamic, and extra-hypothalamic volumes). This data were statistically analysed for correlation with all clinical variables and epilepsy surgery outcome. We reviewed all the classification protocols in the literature. RESULTS: Focal onset impaired awareness seizures started at an earlier age of onset with larger hypothalamic hamartoma volume and dimensions. Lateral extension within the hypothalamus was associated with more severe epilepsy, higher seizure frequency, more severe psychiatric comorbidity, hetero-aggression, hyperkinesia, and school difficulties. Presence of precocious puberty was positively correlated to anterior-posterior extension; tuberal region involvement, hypothalamic hamartoma volume, and type III-VI. Larger hypothalamic hamartoma presented precocious puberty at an earlier age of onset. After Gamma Knife Surgery, epilepsy outcome was better and rapid when lesion is smaller. Post-radiosurgical transient increased seizures were present when the mammillary region was more involved. CONCLUSION: Clinical presentation of epileptic hypothalamic hamartoma is significantly affected by fine topography patterns and invaded hypothalamic areas. Gamma Knife Radiosurgery effect is better and rapid in smaller hamartoma (Type I-III) and seizure outcome was not affected by the invaded hypothalamic areas.

Long-term cognitive outcome after radiosurgery in epileptic hypothalamic hamartomas and review of the literature.

OBJECTIVE: Epileptic patients with hypothalamic hamartoma (HH) frequently present cognitive impairments. Surgical techniques aiming at HH can be very efficient for epilepsy relief and cognitive improvement but are also demonstrated to carry a significant risk of additional reduction in memory function in these already disabled patients. Gamma knife radiosurgery (GKS) offers an efficient minimally invasive procedure. We evaluated the effect of stereotactic radiosurgery on cognitive outcome. METHODS: We designed a prospective single-center case series study. Thirty-nine epileptic patients (median age = 17 years, range = 4-50) with HH underwent preoperative and postoperative testing of intelligence quotient (IQ; all patients), including a working memory component, and other memory function testing (for patients ≥16 years old). All patients were prospectively evaluated and underwent complete presurgical and postsurgical clinical, electrophysiological, endocrinal, and visual assessments. In all patients, the postoperative assessment was performed at least 3 years after radiosurgery. We explored what variables correlate with cognitive outcome. Literature review was done for other surgical techniques and their risks for cognitive complications after surgery. RESULTS: No decline was observed in intellectual ability (including working memory) after GKS, and no memory decline was seen in adults. We observed significant improvement (>1 SD in z-score) in working memory index (46%) and processing speed index (35%), as well as improvement in full-scale IQ (24%), verbal comprehension index (11%), perceptual organization index (21%), verbal learning (20%), and visual learning (33%). Before GKS, the probability of seizure cessation was higher in patients with higher cognitive performance. After GKS, the cognitive improvement was significantly higher in the seizure-free patients compared to the non-seizure-free patients. SIGNIFICANCE: We found clear cognitive improvement in a high percentage of patients but importantly no significant decline in intellectual ability (including working memory) and no decline in memory in adult patients 3 years after GKS. GKS compares favorably to the other surgical techniques in terms of cognitive outcome, with similar seizure freedom.

Clinical evaluation of a real-time inverse planning for Gamma Knife radiosurgery by convex optimization: a prospective comparative trial in a series of vestibular schwannoma patients.

BACKGROUND: Gamma Knife radiosurgery (GKRS) inverse dose planning is currently far from competing effectively with the quality of dose planning developed by experienced experts. A new inverse planning (IP) method based on « efficient convex optimization algorithms ¼ is proposed, providing high-quality dose plans in real time. MATERIALS AND METHODS: Eighty-six patients treated by GKRS for vestibular schwannomas (VS) were recruited. The treatment plans created by the first author, who has 27 years of experience and has developed and delivered more than 15,000 dose plans, served as reference. A first set of basic constraints determined by default led the IP for an initial real-time dose plan. Additional constraints were interactively proposed by the planner to take other parameters into account. A second optimized plan was then calculated by the IP. The primary endpoint was the Paddick Conformity Index (PCI). The statistical analysis was planned on a non-inferiority trial design. Coverage, selectivity, and gradient indexes, dose at the organ(s) at risk, and 12 Gy isodose line volume were compared. RESULTS: After a single run of the IP, the PCI was shown to be non-inferior to that of the "expert." For the expert and the IP, respectively, the median coverage index was 0.99 and 0.98, the median selectivity index 0.92 and 0.90, the median gradient index 2.95 and 2.84, the median dose at the modiolus of the cochlea 2.83 Gy and 2.86 Gy, the median number of shots 14.31 and 24.13, and the median beam-on time 46.20 min and 26.77 min. In a few specific cases, advanced tools of the IP were used to generate a second run by adding new constraints either globally (for higher selectivity) or locally, in order to increase or decrease these constraints focally. CONCLUSION: These preliminary results showed that this new IP method based on « efficient convex optimization algorithms ¼, called IntuitivePlan®, provided high-quality dose plans in real time with excellent coverage, selectivity, and gradient indexes with optimized beam-on time. If the new IP evaluated here is able to compete in real time with the quality of the treatment plans of an expert with extensive radiosurgical experience, this could allow new planners/radiosurgeons with limited or no experience to immediately provide patients with high-quality GKRS for benign and malignant lesions.

VNS implantation in a NF1 patient: massive nerve hypertrophy discovered intra-operatively preventing successful electrode placement. Case report.

For the vast majority of surgeons, no specific investigation is necessary before vagal nerve stimulation (VNS) implantation. We report our intraoperative unexpected finding of a massively enlarged vagus nerve in a patient with neurofibromatosis type 1 (NF1). The nerve hypertrophy prevented wrapping the coils of the helical electrode. The patient had no signs of vagus nerve dysfunction preoperatively (no hoarseness or dysphonia). This exceptional mishap is undoubtedly related to NF1-associated peripheral nerve sheath tumors. Even though it is not advisable to routinely perform any imaging prior to VNS, in such specific context, preoperative imaging work-up, especially cervical ultrasound, might be judicious to rule out any asymptomatic enlarged left vagus nerve.

Effective posterior extension of callosotomy by gamma knife surgery.

Drop attacks are the most responsive seizure type to open callosotomy, however, surgical complications can worsen the prognosis. Various less invasive techniques have been explored in an effort to minimize the risk. We present a patient who suffered from life-threatening traumatizing drop attacks in whom previous open anterior callosotomy and vagal nerve stimulation were unsatisfactory. Following posterior extension of the callosotomy by non-invasive gamma knife surgery, the rate of drop attacks declined from 30 a day to once a day, or every few days over a four-month period, without complications. Open callosotomy is an invasive and high risk treatment option for patients with drop attacks. The procedure has a potential for complications and neurological consequences that can worsen the functional capacity of a patient who already suffers with disability. Recently, in an attempt to decrease the invasiveness associated with this technique, additional technical refinements and less invasive procedures have been explored in a few studies. Here, we report a case of refractory epilepsy with life-threatening traumatizing DA, in which the patient was treated by radiosurgical posterior callosotomy after unsatisfactory open anterior callosotomy and vagal nerve stimulation.

Use of Polyvinyl Alcohol Sponge Cubes for Vagal Nerve Stimulation: A Suggestion for the Wrapping Step. Technical Note and Step-by-Step Operative Technique.

BACKGROUND: Vagal nerve stimulation (VNS) is an approved treatment for epilepsy and depression. Wrapping the helical electrodes around the nerve can prove technically challenging. However, a quick and efficient method to slightly elevate the nerve can highly facilitate this part of the procedure. OBJECTIVE: To provide useful surgical tips to facilitate the procedure. METHODS: Based on experience of more than 150 adult cases for mainly epilepsy (primary lead implant), the authors share their surgical technique to provide the experienced surgeons or newcomers to the field of VNS with some useful tips. All patients signed informed consent according to the local ethics committee guidelines. RESULTS: The article consists of a detailed step-by-step description of the whole procedure illustrated through high-resolution colored photographs of the surgical field. Special reference is made to the usefulness of polyvinyl alcohol (PVA) sponge cubes to elevate the nerve instead of the commonly used silicon vessel loops. CONCLUSION: The use of surgical microscope and PVA sponge cubes to elevate the nerve constitute key points to make VNS an easy surgery.

Establishment of a Therapeutic Ratio for Gamma Knife Radiosurgery of Trigeminal Neuralgia: The Critical Importance of Biologically Effective Dose Versus Physical Dose.

OBJECTIVE: How variations of treatment time affect the safety and efficacy of Gamma Knife (GK) radiosurgery is a matter of considerable debate. With the relative simplicity of treatment planning for trigeminal neuralgia (TN), this question has been addressed in a group of these patients. Using the concept of the biologically effective dose (BED), the effect of the two key variables, dose and treatment time, were considered. METHODS: A retrospective analysis was performed of 408 TN cases treated from 1997 to 2010. Treatment involved the use of a single 4 mm isocenter. If conditions allowed, the isocenter was placed at a median distance of 7.5 mm from the emergence of the trigeminal nerve from the brain stem. The effects were assessed in terms of the incidence of the complication, hypoesthesia, and in terms of efficacy using the incidence of pain free after 30 days and 1 and 2 years. These responses were evaluated with respect to both the physical dose and the BED, the latter using a bi-exponential repair model. RESULTS: RE-evaluation showed that the prescription doses, at the 100% isodose, varied from 75 to 97.9 Gy, delivered in 25-135 minutes. The relationship between the physical dose and the incidence of hypoesthesia was not significant; the overall incidence was ∼20%. However, a clear relationship was found between the BED and the incidence of hypoesthesia, with the incidence increasing from <5% after a BED of ∼1800 Gy2.47 to 42% after ∼2600 Gy2.47. Efficacy, in terms of freedom from pain, was ∼90%, irrespective of the BED (1550-2600 Gy2.47) at 1 and 2 years. The data suggested that "pain free" status developed more slowly at lower BED values. CONCLUSIONS: These results strongly suggest that safety and efficacy might be better achieved by prescribing a specific BED instead of a physical dose. A dose and time to BED conversion table has been prepared to enable iso-BED prescriptions. This finding could dramatically change dose-planning strategies in the future. However, this concept requires validation for other indications for which more complex dose planning is required.

Anterior Thalamic Stimulation Induced Relapsing Encephalitis.

Deep brain stimulation of the anterior thalamic nucleus is one of the promising therapeutic options for epilepsy. Several studies are still under way to further strengthen and clarify the mechanism, efficacy, and complications. Contrary to hardware-related and operation-related events, the stimulation-related adverse effect is mild, target-dependent, and adjustable. We present a case of relapsing herpes simplex encephalitis (HSE) as a newly reported and potentially fatal stimulation-related adverse effect following stimulation of the anterior thalamic nucleus (ANT-DBS) accompanied by fever, confusion, and cognitive impairment in a 32-year-old epileptic patient with a history of herpes meningoencephalitis 31 years earlier. The T2-weighted/FLAIR high-signal intensity in the temporal lobe developed at a "distance" from the stimulation target. The positive polymerase chain reaction of herpes virus deoxyribonucleic acid in the cerebrospinal fluid confirmed the diagnosis. The condition improved partially on acyclovir and stimulation stopped. Seizures disappeared and then returned after few months. The unique case report presents a rationale for considering history of herpes encephalitis as a relative contraindication for ANT-DBS, and HSE relapse should be suspected in patients with post-stimulation fever and/or altered consciousness.