Stereotactic Radiofrequency Thermocoagulation Research Articles

Advances in hypothalamic hamartoma research over the past 30 years (1992-2021): a bibliometric analysis.

Hypothalamic hamartoma (HH) is a rare intracranial disease whose manifestations include gelastic seizures and precocious puberty. The diagnosis and treatment of HH have changed substantially over the past three decades as medical care has improved. Bibliometrics can reveal the evolution and development of a scientific field. Documents on HH were retrieved from the Web of Science Core Collection (WoSCC) database on September 8, 2022. The search terms were as follows: "hypothalamic hamartoma" or "hamartoma of the hypothalamus" or "hypothalamic hamartomas." The types of documents were restricted to articles, case reports, and reviews. VOSviewer, CiteSpace, and the R package "bibliometrix" were used for a bibliometric analysis. A total of 667 independent documents on HH were obtained from the WoSCC database. The most common types of documents were articles (n = 498, 75%) and reviews (n = 103, 15%). The number of annual publications fluctuated but showed an upward trend overall, and the annual growth rate was 6.85%. The cumulative publication data indicated that the most influential journals in the HH field include Epilepsia, Epileptic Disorders, Child's Nervous System, Neurosurgery, and the Journal of Neurosurgery. Kerrigan JF, Ng YT, Rekate HL, Regis J, and Kameyama S were among the most prominent authors in the field of HH, with numerous publications and citations. American research institutions, especially the Barrow Neurological Institute, occupied a pivotal position in HH research. Other countries and institutions were catching up and producing considerable research results. Research on HH has steadily switched its emphasis from Pallister-Hall syndrome (PHS) and precocious puberty to epilepsy and new diagnostic and therapeutic techniques, including Gamma Knife, laser ablation, and interstitial thermal therapy. HH remains a special neurological disease with significant research prospects. The development of novel technologies, including MRI-guided laser-induced thermal therapy (MRg-LiTT) and stereotactic radiofrequency thermocoagulation (RF-TC), has enabled the efficient treatment of gelastic seizures in HH while minimizing the risks associated with craniotomies. Through bibliometric analysis, this study points out the direction for future HH research.

Adult-onset hypothalamic hamartoma: origin of epilepsy?

BackgroundHypothalamic hamartoma (HH) is a congenital non-progressive lesion of hypothalamus during fetal development. Mass-like lesions in different anatomical locations often develop a variously disabling course presenting with cognitive decline, psychiatric symptoms, as well as multiple seizure types. As a rare disease, HH is relatively common in infants and children, but it is extremely rare in adults.Case presentationWe reported a case of adult-onset hypothalamic hamartoma, and summarized and analyzed relevant reports and studies of HH worldwide. The patient had clinical manifestations characterized by multiple seizure forms. After stereotactic radiofrequency thermocoagulation and drug treatment, the condition was effectively controlled. The patient was followed up till October 2022, with no recurrence of seizures.ConclusionsEpilepsy caused by HH can resemble that of temporal lobe seizures, as HH forms a complex epileptogenic network with other regions of the brain through anatomical and functional connections. Early treatment of HH can provide better control of the symptoms of epilepsy, and patients with longer disease courses may have more complications.

Incomplete hippocampal inversion in patients with mutations in genes involved in sonic hedgehog signaling

Sonic hedgehog (Shh) signaling pathways are known to play an important role in the morphological development of the hippocampus in vivo, but their actual roles in humans have not been clarified. Hypothalamic hamartoma (HH) is known to be associated with germline or somatic gene mutations of Shh signaling. We hypothesized that patients with HH and mutations of Shh-related genes also show hippocampal maldevelopment and an abnormal hippocampal infolding angle (HIA). We analyzed 45 patients (age: 1–37 years) with HH who underwent stereotactic radiofrequency thermocoagulation and found Shh-related gene mutations in 20 patients. In addition, 44 pediatric patients without HH (age: 2–25 years) who underwent magnetic resonance imaging (MRI) examinations under the same conditions during the same period were included in this study as a control group. HIA evaluated on MRI was compared between patients with gene mutations and the control group. The median HIA at the cerebral peduncle slice in patients with the gene mutation was 74.36° on the left and 76.11° on the right, and these values were significantly smaller than the corresponding values in the control group (80.46° and 80.56°, respectively, p < 0.01). Thus, mutations of Shh-related genes were correlated to incomplete hippocampal inversion. The HIA, particularly at the cerebral peduncle slice, is a potential indicator of abnormalities of the Shh-signaling pathway.

MRI-Negative Medial Temporal Lobe Epilepsy can Benefit from Stereotactic Radiofrequency Thermocoagulation Applied to the Amygdalohippocampal Complex.

Seizure control (SC) is often poor in cases of magnetic resonance imaging- negative epilepsy after resection surgery. This study aimed to evaluate the therapeutic efficacy of depth-electrode-guided stereotactic radiofrequency thermocoagulation (RFTC) applied to the amygdalohippocampal complex (AHC) for the treatment of patients with MRI-negative medial temporal lobe epilepsy. A total of 62 cases with magnetic resonance imaging-negative medial temporal lobe epilepsy were retrospectively studied after the application of depth-electrode-guided RFTC to the AHC. Single-target coagulations were applied to all patients, and multi-target coagulations were applied to those patients who did not experience significant reductions in discharges after the first target ablation. Bilateral-target coagulations were applied to bilateral medial temporal lobe epilepsy patients, using single target ablation applied to each side. After 24-83 months of follow-up, 32/62 (51.61%) patients became seizure-free, and 35/62 (56.45%) patients reported significant reductions in seizure episodes. The total effective rate was 69.35% (43/62). No significant differences were observed for SC among the single-target, multi-target, and bilateral-target groups. However, a significant difference was observed for the reduction in epileptic discharges after coagulations between those patients who became seizure-free and those who did not. Magnetic resonance imaging-negative medial temporal lobe epilepsy patients can benefit from RFTC applied to the AHC. A significant reduction in epileptic discharges observed during operations after RFTC is applied may predict good SC. RFTC applied to the AHC could be considered a promising method for the treatment of magnetic resonance imaging-negative medial temporal lobe epilepsy patients.

A Special Approach for Stereotactic Radiofrequency Thermocoagulation of Hypothalamic Hamartomas With Bilateral Attachments to the Hypothalamus: The Transthird Ventricular Approach to the Contralateral Attachment.

Disconnection surgery for the treatment of epileptic hypothalamic hamartomas (HHs) is strategically difficult in cases with complex-shaped HHs, especially with bilateral hypothalamic attachments, despite its effectiveness. To evaluate the feasibility of a new approach for stereotactic radiofrequency thermocoagulation (SRT) using penetration of the third ventricle (SRT-TT) aiming to disconnect bilateral hypothalamic attachments in a single-staged, unilateral procedure. Ninety patients (median age at surgery, 5.0 years) who had HHs with bilateral hypothalamic attachments and were followed for at least 1 year after their last SRT were retrospectively reviewed. Thirty-three patients underwent SRT-TT as initial surgery. Of the 58 patients after mid-2013 when SRT-TT was introduced, 33 underwent SRT-TT and 12 (20.7%) required reoperation (ReSRT), whereas 20 of 57 patients (35.1%) without SRT-TT underwent reoperation. Reoperation was required in significantly fewer patients after mid-2013 (n = 12 of 58, 20.7%) than before mid-2013 (n = 15 of 32, 46.9%) ( P = .01). Final seizure freedoms were not different between before and after mid-2013 (gelastic seizure freedom, n = 30 [93.8%] vs n = 49 [84.5%] and other types of seizure freedom, n = 21 of 31 [67.7%] vs n = 32 of 38 [84.2%]). Persistent complications were less in SRT-TT than in ReSRT using the bilateral approach, but not significantly. However, hormonal replacement was required significantly more often in ReSRT using the bilateral approach (4 of 9, 44.4%) than in SRT-TT (3 of 32, 9.4%) ( P = .01). SRT-TT enabled disconnection of bilateral attachments of HHs in a single-staged procedure, which reduced the additional invasiveness of reoperation. Moreover, SRT-TT reduced damage to the contralateral hypothalamus, with fewer endocrinological complications than the bilateral approach.

Long-term seizure outcomes in patients with hypothalamic hamartoma treated by stereotactic radiofrequency thermocoagulation.

To investigate long-term seizure outcomes in patients with hypothalamic hamartoma (HH) following stereotactic radiofrequency thermocoagulation (SRT). A total of 131 patients with HH who underwent SRT and were followed for at least three years after the last SRT were enrolled. Seizure outcomes were evaluated for gelastic seizures (GS) and other types of seizures (nGS) separately using the International League Against Epilepsy classification. Classes 1 and 2 were considered seizure-free. Kaplan-Meier survival analyses were used to estimate the proportion remaining seizure-free after the first and last SRTs. Risk factors relating to outcomes were analyzed by log-rank tests and a multivariate Cox proportional hazards model. Reoperation was performed in 34 patients (26.2%). Median total follow-up was 61 (range, 36-202) months. Seizure freedom was obtained in 116 patients (88.6%) for GS and 85 of 108 patients (78.7%) for nGS at the last follow-up. Mean GS-free survival times improved from after the first (64.1 [95%CI 57.3-70.9] months) to after the last SRT (80.2 [95%CI 75.7-84.8] months). About 90% of GS recurrences after the first SRT were found within 6months, though a few patients recurred more than 2years after the first SRT. On the other hand, mean nGS-free survival times after the first and last SRTs were not different between after the first SRT (84.4 [95%CI 73.0-90.7] months) and after the last SRT (83.1 [95%CI 74.1-92.0] months). There was no factor related to GS outcomes, but the significant factor for nGS-free survival after the last SRT was multiple previous treatments (p=0.01, hazard ratio=15.65, 95%CI 1.79-137.16). The last SRT was almost equivalent to achieving complete disconnection of HHs from the hypothalamus according to our strategy. Considering the epileptogenic network, GS outcomes depend on complete disconnection, whereas nGS outcomes are not affected by surgical factors but independency of secondary epileptogenesis.

Location of emotional corticobulbar tract in the internal capsule

Emotional facial paresis (EFP) is a rare neurological symptom with intact volitional facial movement. The exact location of emotional corticobulbar tract remains unclear. EFP was frequently recognized following the surgery of stereotactic radiofrequency thermocoagulation for hypothalamic hamartoma in 84.5% of 58 patients. To examine our hypothesis that EFP might be caused by stereotactic trajectories passing through an area including the internal capsule (IC), topographical locations of trajectories were analyzed and compared between the EFP-positive group (n = 41) and the EFP-negative group (n = 8). In the EFP-positive group, multiple (2 to 5) trajectories focused within the genu of the IC in 31 (75.6%) cases, whereas a single trajectory passed through the genu in 8 (19.5%) cases. In the EFP-negative group, 6 (75.0%) of 8 patients had a single trajectory and only one patient had two trajectories passing through the genu of the IC. The ratio between multiple trajectories and a single trajectory relevant to the genu differed significantly between two groups (p < 0.01). The multiple trajectories focusing in the genu have high risks of EFP, whereas a single trajectory seemed to incidentally cause EFP. The results proved our hypothesis and provided a high probability that the emotional corticobulbar tract passes through the genu rather than anterior or posterior limbs of the IC. The location of the emotional corticobulbar tract is in the genu of the IC.

Significance of the electrophysiological border between hypothalamic hamartomas and the hypothalamus for the target of ablation surgery identified by intraoperative semimicrorecording.

Ablation surgery has become the first line of treatment for hypothalamic hamartomas (HHs). For effective treatment, optimum targeting of ablation is mandatory. The present study aimed to evaluate the correspondence between the electrophysiological features of HHs and morphological targeting by semimicrorecording during stereotactic radiofrequency thermocoagulation (SRT). Eighty HH patients who underwent SRT were involved. Semimicrorecording was performed on the first trajectory. The distance from the center of the target at the morphological border (TMB) determined by magnetic resonance imaging, differences in discharge patterns, and area potentials (APs) were measured. The electrophysiological border (EB) between the HH and hypothalamus was detected by semimicrorecording in 73 (91.3%), AP increase (API) in the HH was detected in 31 (38.8%), and spike discharges (SDs) of the HH were detected in 56 patients (70.0%). Semimicrorecording showed significantly different APs among structures passing through the trajectory, except between API and SDs. The median distances from the center of the TMB to the EB, API, SDs, and AP decline were -3.50, -2.49, -1.38, and +2.00mm, respectively. The electrophysiological features of HHs were shown by semimicrorecording during SRT. The EB corresponded to the morphological border. The electrophysiologically active area of HHs was located near the border. Ablation surgery should focus on disconnection at the border between the HH and the hypothalamus to maximize its effectiveness, as well as to reduce complications.

Stereotactic radiofrequency thermocoagulation and resective surgery for patients with hypothalamic hamartoma.

In this study, the authors compared the efficacy and safety of stereotactic radiofrequency thermocoagulation (SRT) and resective surgery (RS) for patients with hypothalamic hamartoma (HH). The authors included all patients with HHs who were treated by SRT or hamartoma resection. Seizure outcomes were assessed by blinded observers according to the International League Against Epilepsy (ILAE) classification. Favorable seizure outcomes were defined as ILAE classes 1 and 2, and unfavorable seizure outcomes were defined as ILAE classes 3-6. Twenty-nine patients who underwent SRT or RS met the inclusion criteria; 3 were excluded because they had completed less than 12 months of follow-up. Most of the patients (20 of 26; 76.9%) had small HHs (i.e., maximum HH diameter less than 20 mm). The patients' follow-up time ranged from 12 to 66 months (median 60 months). At the last follow-up, favorable outcomes were observed in 9 patients (69.2%) who had undergone SRT and 10 patients (76.9%) who had undergone HH resection. No significant difference was found in seizure outcomes between SRT and RS recipients. Patients with giant HHs were more likely than patients with smaller tumors to undergo multiple resections (p = 0.043, univariate logistic regression; significant). However, no significant difference was found between SRT and RS recipients in terms of the number of procedures per patient. SRT recipients had fewer and less-severe adverse events than RS recipients. For patients with small HHs, SRT provides similar seizure outcomes to RS with a less invasive procedure. Patients who underwent SRT experienced fewer and lighter adverse effects than patients who had RS. Patients with giant HHs were more likely to undergo multiple HH resections.

Repeat stereotactic radiofrequency thermocoagulation in patients with hypothalamic hamartoma and seizure recurrence.

ObjectiveTo evaluate the feasibility of repeat stereotactic radiofrequency thermocoagulation (re‐SRT) for patients with hypothalamic hamartoma (HH) and to clarify clinical and surgical factors for seizure outcomes.MethodsHypothalamic hamartoma patients with gelastic seizures (GSs) who underwent SRT were retrospectively reviewed. Seizure outcomes were evaluated separately for GS and other types of seizures (non‐GS). Surgical complications were compared between re‐SRT and first SRT. Clinical and surgical factors related to both seizure recurrences after first SRT and final seizure outcomes were analyzed.ResultsParticipants comprised 150 patients (92 males; median age at surgery, 8 years; range, 1.7‐50 years). Of those, 122 (81.3%) had non‐GS. Forty‐three patients (28.7%) underwent re‐SRT. Freedom from GS was achieved by first SRT in 103 patients (68.7%), second SRT in 30/40 (67.5%), third SRT in 3/10 (30.0%), and fourth SRT in 2/3 (66.7%). Finally, 135 patients (90.0%) became GS‐free. Ninety patients (73.8%) achieved non‐GS freedom, with first SRT in all except one case. Transient complications were more frequent with first SRT (118/150, 78.7%) than re‐SRT (35/56, 62.5%), whereas persistent complications were more frequent with re‐SRT (7/56, 12.5%) than with first SRT (3/150, 2.0%). Multivariate analyses revealed only younger age at surgery (≤1 year) as related to GS recurrence after first SRT, with no variables affecting final GS outcomes. Meanwhile, seizure type (tonic seizure), intellectual disability, and genetic syndromes were significant factors for both non‐GS recurrence and final outcomes. Multiple previous treatments were significantly related to final non‐GS outcomes as well. Size and subtype of HH and surgical factors were unrelated to seizure outcomes.SignificanceRepeat stereotactic radiofrequency thermocoagulation provides potential opportunities to achieve freedom from recurrent GS, albeit with increased risks of persistent complications. Non‐GS and intellectual disability could offer early surgical indications, and repeated ineffective treatments should be avoided.

Stereotactic radiofrequency thermocoagulation application in the anterior limbs of patients’ internal capsules in treating intractable tic disorders

Purpose To investigate the effect of applying stereotactic radiofrequency thermocoagulation in the anterior limbs of patients’ internal capsules in treating intractable tic disorders. Materials and methods Patients diagnosed with intractable tic disorders were prospectively enrolled and treated using stereotactic radiofrequency thermocoagulation in the anterior limbs of the internal capsules. Periprocedural complications, effects, and follow-up outcomes were then analyzed. Results Fifty patients were enrolled, including 38 with Tourette syndrome and 12 with persistent refractory vocal or motor tic disorders. The radiofrequency thermocoagulation procedure was performed successfully in all patients. Five participants (10%) experienced periprocedural complications, including one having a slight hemiplegia, two developing fevers (4%), and two developing urination disorders (4%). The participants underwent a follow-up for 12 months, with excellent effects being achieved in 23 patients (46%), prominent results in 13 (26%), good results in 10 (20%), and invalid results in 4 (8%), reaching an efficacy rate of 92% (46/50). Thirty-six patients experienced excellent and prominent effects, with no additional management after the radiofrequency ablation being needed, achieving a success rate of 72%. After radiofrequency thermocoagulation, the Yale Global Tic Severity Scale (YGTSS) scores were significantly reduced (p < .01) when compared with those before the procedure. Following this procedure, participants’ serum dopamine levels (SDA) significantly decreased (p < .05), while their serotonin levels were significantly elevated (p < .05) when compared to the measurements taken before the procedure. Conclusion Stereotactic radiofrequency thermocoagulation applied to the anterior limbs of patients’ internal capsules may be effective for treating intractable tic disorders, without risk of serious complications.

Effects of stereotactic radiofrequency thermocoagulation in the globus pallidus internus on refractory tic disorders

Objective To investigate the effect of stereotactic radiofrequency thermocoagulation in the globus pallidus internus on refractory tic disorders. Materials and methods Forty patients with refractory tic disorders were enrolled between January 2015 and July 2017 to experience stereotactic radiofrequency thermocoagulation in the globus pallidus internus. All clinical data, Yale Global Tic Severity Scale (YGTSS) scores, serum dopamine (SDA), and 5-hydroxytryptamine (5-HT) were analyzed. Results Radiofrequency thermocoagulation was successfully performed in all patients. Periprocedural complications occurred in two patients (5.0%), one with fever (2.5%) and one with a urination disorder (2.5%); both returned to normal after treatment. After 12 months of follow-ups, excellent improvement was exhibited in 18 patients (45.0%), marked improvement in 10 (25.0%), good improvement in 9 (22.5%), and invalid in 3 (7.5%), with a total efficacy rate of 92.5% (37/40). Twenty-eight patients (70%) showed excellent or marked improvement without additional treatment after surgery. YGTSS scores were significantly (p < 0.05) decreased after compared with before thermocoagulation. SDA was significantly (p < 0.05) decreased 6 months (80.78 ± 18.82 ng/ml) and 12 months (75.65 ± 15.23 ng/ml) after compared with before (125.63 ± 35.26 ng/ml) surgery, whereas 5-HT was significantly (p < 0.05) increased 6 months (58.93 ± 16.88 ng/ml) and 12 months (62.63 ± 15.21 ng/ml) after compared with before (35.62 ± 3.41 ng/ml) surgery. Conclusion Stereotactic radiofrequency thermocoagulation can be safely applied in the globus pallidus internus to treat refractory tic disorders, resulting in significant tic symptom relief and a decrease in SDA but increase in 5-HT.

Stereotactic thermocoagulation for insular epilepsy: Lessons from successes and failures.

To assess factors associated with favorable outcome in refractory insular epilepsy treated by volume-based stereotactic radiofrequency thermocoagulation (RFTC). We performed volume-based RFTC in 19 patients (11 males, 7-44years old). The volume for thermocoagulation was identified by multimodal data including electroencephalography (EEG)-video, magnetic resonance imaging (MRI), and fluorodeoxyglucose-positron emission tomography (PET) in all patients, and epileptogenic zone (EZ) was assessed by stereo-electroencephalography (SEEG) in 16. MRI showed insular lesions in four patients (benign tumors, n = 2; focal cortical dysplasia [FCD], n = 1; polymicrogyria, n = 1). MRI was negative in 15 cases; however, PET was positive in 18, and FCD pattern was detected by SEEG in nine cases. The dominant hemisphere was involved in 12 cases. RFTC was performed as a separate procedure after SEEG, or as a single MRI-guided procedure. The insular volume to be coagulated was determined by a tridimensional identification of the epileptogenic cortex using MRI, PET, and SEEG, and was destroyed with coalescent thermal lesions. Seizure-free outcome was achieved in 10 patients (53%), including Engel class IA in three (follow-up = 1-12years, mean = 5.4). The responder rate (including Engel classes I-III) was 89%. Transient postoperative deficits (mild hemiparesia, dysarthria, hypoesthesia, dysgeusia) were observed in eight patients (42%), with rapid and total recovery in all but one with persistent mild dysarthria. Neurological deficits were related to higher number of RFTC procedures (P=.036) and greater volume of RFTC (P=.028). Neuropsychological status was unchanged or improved in all; however, psychiatric status transitorily worsened in three patients. Factors contributing to seizure-free outcome were the detection of FCD pattern (P=.009), localized EZ (P=.038), low RFTC volume (P=.002), low number of RFTC procedures (P=.001), and low RFTC volume/number ratio (P=.012). Optimal volume of RFTC around 2cm3 offered the best compromise between efficacy and safety. RFTC may be curative in insular epilepsy after accurate localization of EZ with SEEG. Best outcome was associated with low volume of thermolesions.

Termocoagulação por Radiofrequência Estereotáxica para Tratamento do Hamartoma Hipotalâmico

Introdução: Os hamartomas hipotalâmicos, que ainda não possuem causa definida, são compostos de tecidos heterotópicos raros e histologicamente benignos. Classicamente, se associam a crises gelásticas, mas não é incomum que se manifestem através de outros tipos de crises convulsivas. Os pacientes com hamartomas hipotalâmicos comumente apresentam distúrbios cognitivos, desordens endócrinas e transtornos psiquiátricos. Recomenda-se, como tratamento padrão, o uso de medicação para controle dos sintomas, enquanto para os pacientes refratários, a alternativa é a abordagem cirúrgica. Objetivo: Discutir as indicações, fazer comparações entre técnicas cirúrgicas, evidenciar a utilidade e o sucesso da termocoagulação por radiofrequência estereotáxica em uma paciente de 26 anos com diagnóstico de hamartoma hipotalâmico e comparar as vantagens e as desvantagens das várias técnicas cirúrgicas para este fim. Conclusão: A utilização da técnica de termocoagulação por radiofrequência guiada por método estereotáxico é um procedimento viável e seguro para pacientes com diagnóstico de hamartoma hipotalâmico cuidadosamente selecionados.

Lesion focused radiofrequency thermocoagulation of bottom-of-sulcus focal cortical dysplasia type IIb: Conceptional considerations with regard to the epileptogenic zone

Small bottom-of-sulcus focal cortical dysplasias (BOS-FCD) type IIb are intrinsically epileptogenic lesions often responsible for pharmacoresistant epilepsy. They are increasingly well demarcated in vivo from surrounding cortex and white matter by 3 T magnetic resonance imaging (MRI). These facts and frequent seizure freedom after just narrow resections allow questioning the classical concept of epilepsy surgery in which the epileptogenic lesion is generally considered only one part of the epileptogenic zone and the resection volume categorically has to exceed lesion limits.This study approaches this question by analyzing procedures of strongly lesion focused stereotactic radiofrequency thermocoagulation (L-RFTC) applied to BOS-FCD IIb. Seven patients with BOS-FCD IIb were treated, three had invasive EEG recordings prior to L-RFTC, all had intraoperative stereotactic EEG-recordings. Perilesional epileptic discharges (PLD) were documented in all patients. Coagulation was planned based on MRI, the maximum extension beyond lesion limits due to PLD was 4.8 mm. Although in all patients other areas of PLD remained uncoagulated, seizure freedom was achieved in four of five patients with complete lesion coagulation.In summary, due to the minimal extensions of lesion coagulations, current experience with L-RFTC of BOS-FCD IIb is not yet sufficient to rebut the significance of PLD. It encourages, however, further research on even stronger MRI guidance and possibly even ignorance of PLD in BOS-FCD IIb. It appears possible that in some BOS-FCD IIB the complete epileptogenic zone (according to Lüders) might lie inside the MRI visible lesion. This would influence the understanding of the concept of cortical zones.

Stereotactic Radiofrequency Thermocoagulation of Hypothalamic Hamartoma Using Robotic Guidance (ROSA) Coregistered with O-arm Guidance-Preliminary Technical Note.

Treatment options for hypothalamic hamartoma (HH) include microvascular surgery, stereotactic radiofrequency thermocoagulation (SRT), laser interstitial thermal therapy, or Gamma Knife surgery. During SRT, thermographic monitoring cannot be performed and therefore highly accurate placement of electrode and confirmation of its position are required. We have used robotic guidance (ROSA) and coregistered it with O-arm for performing ablation of hamartoma. Five patients with HH and gelastic seizures underwent SRT. Robotic guidance (ROSA) was used for placement of electrodes. An O-arm was used for coregistering and confirming the robotic trajectory with real-time intraoperative imaging. Intraoperative computed tomography was merged with preoperative magnetic resonance imaging to confirm the exact position and trajectory of the electrode. Ablation was performed using a radiofrequency generator (70°C for 60 seconds). Multiple target sites were ablated to achieve proper ablation and disconnection. Most patients (4/5) had International League Against Epilepsy class I outcome. One patient 2 sittings of lesioning. All but 1 electrode could be placed in the planned trajectories. One electrode was detected to have a medial deviation, and it had to be revised. No permanent complication was observed. SRT is a cost-effective method of treating HH when compared with laser interstitial thermal therapy. With the use of a robotic arm we have demonstrated accurate placement of electrodes. Intraoperative computed tomography acquired using an O-arm can be merged with preoperative magnetic resonance imaging. This confirms electrode location and trajectory on a real-time basis by performing intraoperative imaging. This method is safe and can be used for radiofrequency ablation of HH.

Predictors of cognitive function in patients with hypothalamic hamartoma following stereotactic radiofrequency thermocoagulation surgery.

To determine the predictors of cognitive function in patients with drug-resistant gelastic seizures (GS) related to hypothalamic hamartoma (HH) before and after stereotactic radiofrequency thermocoagulation surgery (SRT). We studied 88 patients with HH who underwent SRT between October 1997 and December 2014. Patients received neuropsychological tests preoperatively and postoperatively. Based on the preoperative measures, patients were categorized as "high-functioning" (full-scale intelligence quotient [FSIQ] ≥70; n = 48) and "low-functioning" group (FSIQ <70; n = 40). Univariate and multivariate linear regression analyses determined the clinical, electroencephalography (EEG), and imaging factors associated with preoperative cognitive function as well as postoperative cognitive change. Eighty-seven patients (98.8%) were followed postoperatively for an average of 3.3 years, and 75 (85.2%) of them achieved GS remission at the last hospital visit. Neuropsychological performance was significantly improved after surgery in both groups. Multivariate linear regression analysis showed that a smaller HH size (p = 0.002) and a smaller number of antiepileptic drugs (p < 0.001) were preoperatively associated with better neuropsychological performance. Multivariate linear regression analysis showed that better postoperative improvement in cognition was associated with a shorter duration of epilepsy (p = 0.03). Cognitive impairment related to epileptic encephalopathy may improve following SRT in substantial proportions of HH patients. Reduced improvement in postoperative cognitive function in patients with longer duration of epilepsy warrants further studies to determine if earlier SRT provides a greater chance of postoperative cognitive improvement in patients with HH.

Stereotactic Radiofrequency Thermocoagulation (L-RFTC) of Focal Cortical Dysplasias: Applicable to Children?

Stereotactic Radiofrequency Thermocoagulation (L-RFTC) of Focal Cortical Dysplasias: Applicable to Children?

Lesion guided stereotactic radiofrequency thermocoagulation for palliative, in selected cases curative epilepsy surgery

IntroductionResective epilepsy surgery is an established treatment option in patients with pharmacoresistant, lesion related epilepsy. Yet, if the presurgical work-up proves multi-focal organization of the epileptogenic zone, or the area of intended resection is close to eloquent brain areas, patients may decide against resections because of an unfavorable risk–benefit-ratio. We assess if lesion guided cortical stereotactic radiofrequency thermocoagulation (L-RFTC) is a potential surgical alternative in these patients. MethodsWe performed seven procedures of L-RFTC. Three patients had monofocal epilepsy arising close to eloquent structures; in four, invasive pre-surgical workup documented monofocal seizure onset but strong interictal epileptic activity also independent and distant from the seizure onset zone. L-RFTC was restricted to the lesional area (=seizure onset site). Results12 to 37 months after RFTC worthwhile seizure improvement was achieved in 6 patients. One patient became seizure free following complete coagulation of a focal cortical dysplasia, two had had 1–2 auras under tapered but not under continued medication. In one patient only subclinical seizures persisted. In one patient hypermotor seizures were transformed into milder short tonic seizures and another one had a seizure reduction by 50%. Only one patient did not profit at all. One patient developed a persisting neurological deficit. SignificanceIn patients with complex epileptogenic zones L-RFTC can lead to worthwhile seizure reduction. This qualifies this procedure as a palliative surgical technique with potential good risk–benefit ratio. In patients with small focal cortical dysplasias L-RFTC may even allow minimal-invasive surgery with curative intention.

Stereotactic radiofrequency thermocoagulation for giant hypothalamic hamartoma.

OBJECTIVE The authors undertook this study to validate the feasibility and safety of stereotactic radiofrequency thermocoagulation (SRT) for the surgical treatment of giant hypothalamic hamartoma (HH). METHODS Of the 109 patients who underwent SRT for hypothalamic hamartoma (HH) at the authors' institution between 1997 and 2013, 16 patients (9 female, 7 male) had giant HHs (maximum diameter ≥ 30 mm). The clinical records of these 16 patients were retrospectively reviewed. RESULTS The patients' age at first SRT ranged from 1 to 22 years (median 5 years). The maximum diameter of their HHs was 30-80 mm (mean 38.5 mm). Eleven HHs had bilateral attachments to the hypothalamus. All patients had gelastic seizures (GS), and 12 had types of seizures other than GS. Some of these patients also had mental retardation (n = 10, 62.5%), behavioral disorders (n = 8, 50.0%), and precocious puberty (n = 11, 68.8%). A total of 22 SRT procedures were performed; 5 patients underwent repeat SRT procedures. There was no mortality or permanent morbidity. After 17 of the 22 procedures, the patients experienced transient complications, including high fever (n = 7), hyperphagia (n = 3), hyponatremia (n = 6), disturbance of consciousness (n = 1), cyst enlargement (n = 1), and epidural hematoma (n = 1). Thirteen patients (81.3%) achieved freedom from GS after the final SRT procedure during a follow-up period ranging from 6 to 60 months (mean 23 months). Twelve patients had nongelastic seizures in addition to GS, and 7 (58.3%) of these 12 patients experienced freedom from their nongelastic seizures. CONCLUSIONS SRT provided minimal invasiveness and excellent seizure outcomes even in patients with giant HHs. Repeat SRT is safe for residual GS. SRT is a feasible single surgical strategy for HH regardless of the tumor's size or shape.