Radiosurgery for hypothalamic hamartomas

Stereotactic radiosurgery as the initial management option for small-volume hypothalamic hamartomas with intractable epilepsy: a 35-year institutional experience and systematic review

OBJECTIVE

Young patients with hypothalamic hamartomas (HHs) often present with intractable epilepsy. Currently there are no established management guidelines for HH. The authors retrospectively reviewed their single-institution experience to delineate the role of stereotactic radiosurgery (SRS).

METHODS

Seven patients with HHs (4 females; median age 13.7 years, range 2.5-25 years) with no prior resection underwent SRS between 1987 and 2022. The clinical history, epilepsy profile, radiographic findings, and neurological outcomes were characterized. HH topographical types were classified according to the Régis classification. Outcome measures included Engel seizure classification, HH response, and the need for additional surgical interventions.

RESULTS

All patients had Engel class IV epilepsy. A Leksell Gamma Knife was used to deliver a median margin dose of 18 Gy (range 16-20 Gy) to a median hamartoma volume of 0.37 cm3 (range 0.20-0.89 cm3). Seizure reduction was confirmed in 6 patients, and 2 patients had regression of their hamartoma. Two patients underwent resection and/or laser interstitial thermal therapy after SRS. At follow-up, 1 patient was seizure free, 4 patients achieved Engel class II, 1 patient had Engel class III, and 1 patient had Engel class IV seizure outcomes.

CONCLUSIONS

SRS as the initial management option for HH was associated with a low risk of adverse effects. In this institutional series reviewing small-volume HHs treated with SRS, no adverse radiation effect was detected, and the majority of patients experienced seizure reduction. SRS should be considered as the first-line treatment for seizure control in patients with small-volume HHs.

Image-guided LINAC radiosurgery in hypothalamic hamartomas

Introduction

Hypothalamic hamartomas (HH) are developmental malformations that are associated with mild to severe drug-refractory epilepsy. Stereotactic radiosurgery (SRS) is an emerging non-invasive option for the treatment of small and medium-sized HH, providing good seizure outcomes without neurological complications. Here, we report our experience treating HH with frameless LINAC SRS.

Materials and methods

We retrospectively collected clinical and neuroradiological data of ten subjects with HH-related epilepsy that underwent frameless image-guided SRS.

Results

All patients underwent single-fraction SRS using a mean prescribed dose of 16.27 Gy (range 16–18 Gy). The median prescription isodose was 79% (range 65–81 Gy). The mean target volume was 0.64 cc (range 0.26–1.16 cc). Eight patients experienced complete or near complete seizure freedom (Engel class I and II). Five patients achieved complete seizure control within 4 to 18 months after the treatment. Four patients achieved Engel class II outcome, with stable results. One patient had a reduction of seizure burden superior to 50% (Engel class III). One patient had no benefit at all (Engel class IV) and refused further treatments. Overall, at the last follow-up, three patients experience class I, five class II, one class III and one class IV outcome. No neurological complications were reported.

Conclusions

Frameless LINAC SRS provides good seizure and long-term neuropsychosocial outcome, without the risks of neurological complications inherently associated with microsurgical resection.

A systematic review of stereotactic radiofrequency ablation for hypothalamic hamartomas

BACKGROUND

The seizure activity associated with hypothalamic hamartomas (HHs) is refractory to medical management and surgical intervention is often required. Stereotactic Radiofrequency Ablation (SRFA) is a minimally invasive technique offering targeted lesion ablation with a reduced risk of complications.

OBJECTIVE

Here, we review the current literature on the use of SRFA for HHs.

METHODS

This study was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for systematic literature review. A database search of PubMed, Cochrane, Embase, and Web of Science was conducted in July 2020.

RESULTS

A total of 12 articles were included in this review, showing outcomes for 185 unique patients. Of these patients, 142 (76.8%) experienced some extent of therapeutic benefit in alleviating seizures following SRFA, with 128 (69.2%) patients achieving complete freedom from seizures. Common transient complications included hyponatremia (52 patients, 28.1%), hyperphagia (48 patients, 25.9%), hyperthermia (47 patients, 25.4%), Horner's syndrome (103 patients, 55.7%), and weight gain (75 patients, 40.5%).

CONCLUSIONS

SRFA is a potential therapy for patients with HHs, especially when resection confers significant risk to surrounding structures. Multiple rounds of SRFA treatment may be needed in approximately a quarter of patients to improve gelastic seizure outcomes but may not affect non-gelastic seizures. There is limited data on the use of SRFA for HHs and further case series and clinical trials are needed to establish the use of SRFA for HHs.

Is surgery effective for treating hypothalamic hamartoma causing isolated central precocious puberty? A systematic review

The aim of this review was to determine the role of surgery in treating hypothalamic hamartoma (HH) causing isolated central precocious puberty (CPP). Literature review was done according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Patients with isolated CPP due to HH, managed with surgical resection, were included. We found 33 studies, reporting 103 patients (76 pedunculated, 27 sessile). Patients were considered "cured" if the symptoms of PP had regressed and the hormone profile had normalized after surgery. Indications for surgery included hamartoma deemed surgically resectable (n-12), for the purpose of tissue diagnosis (n-3), partial response/failure of preoperative therapy (n-9), and unable to afford/to avoid long-term medical therapy (n-7). The extent of resection was total (TR) (n-39), near total/subtotal (NTR/STR) (n-20), partial (PR) (n-35), or unspecified (n-9). On follow-up (range: 3 months-16 years), 73.6% (56/76) of patients with pedunculated HH were cured, while 17.1% (13/76) had partial relief. Only 3/27 (11.1%) of patients with sessile HH were cured. All patients with a pedunculated hamartoma who underwent TR (n=36) improved, with 88.88% cured of the symptoms. Surgery had no effect in 17/23 (73.9%) patients with sessile HH who underwent PR. Psychological symptoms improved in 10/11 patients. There was no mortality. Permanent complications, in the form of 3rd nerve palsy, occurred in 3.7% (2/54) of the patients. To conclude, in the current era of availability of GnRH analogs, surgical resection in a subset of patients may be acceptable especially for small pedunculated hamartomas.

Hamartoma of the optic nerve in a young child—case report and review of the literature

PURPOSE

Hamartomas are well described but yet incompletely understood sporadic benign lesions that can arise in various locations. Hypothalamic hamartomas of infancy are often associated with severe developmental disturbances. We present a case of an infant boy with a hamartoma that arises from the optic nerve and lead to progressive unspecific seizure activity, behavioral problems and precautious puberty.

METHODS

A 1-year-old male patient was presented with horizontal nystagmus and developmental retardation. Magnetic resonance imaging (MRI) with contrast revealed an isointense mass ventral of the chiasm consistent with a hamartoma. Soon after the MRI, the mother of the patient reported gelastic-like seizures. The patient was evaluated by an interdisciplinary team, and surgery was recommended. Intraoperatively, a firm attachment to the optic nerve was recognized and a thin remnant layer of tissue was left behind.

RESULTS

After an uncomplicated near total resection, the patient improved significantly. After 6 months, the frequency of seizures reoccurred, which were again unresponsive to antiepileptic medication. In a second operation, a complete resection of the remnants was performed, and the patient showed lasting clinical improvement.

CONCLUSION

We conclude that hamartomas mimicking hypothalamic symptoms can also arise from the optic pathway and that a reoperation, if feasible, of even small remnants is essential in order to achieve lasting symptom relieve.

How would we deal with hypothalamic hamartomas?

Hypothalamic hamartoma (HH) is usually associated with refractory epilepsy, cognitive impairment, and behavioral disturbance. There is now increasing evidence that HH can be treated effectively with a variety of neurosurgical approaches. Treatment options for intractable gelastic seizure in HH patients include direct open surgery with craniotomy, endoscopic surgery, radiosurgery with gamma knife and stereotactic radiofrequency thermocoagulation. Selection of treatment modalities depends on type and size of the HH and the surgeon’s preference. Two surgical techniques, resection and disconnection, had been described with favorable outcomes. Pretreatment evaluation, patient selection, surgical techniques, complications, and possible selection of treatment are discussed.

Endoscopic disconnection of hypothalamic hamartomas: safety and feasibility of robot-assisted, thulium laser-based procedures

OBJECT

Hypothalamic hamartomas (HH) may induce drug-resistant epilepsy (DRE), thereby requiring surgical treatment. Conventionally, treatment is aimed at removing the lesion, but a disconnection procedure has been shown to be safer and at least as effective. The thulium laser (Revolix) has been recently introduced in urological endoscopy because of its ability to deliver a smooth cut with good control of the extent of tissue damage. The authors sought to analyze the safety and efficacy of the thulium 2-μm laser applied through navigated, robot-assisted endoscopy in disconnection surgery for HHs.

METHODS

Twenty patients with HH who were drug resistant were treated during a 12-month period. Conventional disconnection by monopolar coagulation (endoscopic electrode) was performed in 13 patients, and thulium laser disconnection was performed in the remaining 7 patients. The endoscope was inserted into the ventricle contralateral to the attachment of the HH on the third ventricular wall. Results in terms of safety, efficacy, and ease of use of the instrument were analyzed.

RESULTS

All 20 patients achieved a satisfactory postoperative Engel score (Classes I-III). At 12 months, the Engel class was I or II in 8 of 13 patients (61.5%) who underwent monopolar coagulation and in 6 of 7 patients (85.7%) who underwent laser disconnection (p = 0.04). Seven of 13 patients (53.8%) who underwent monopolar coagulator disconnection and 2 of 7 patients (28.6%) who underwent laser disconnection had immediate postoperative complications. At the 3-month follow-up, only 2 patients (15.4%) treated by coagulation still experienced mild surgery-related recent memory deficits. No complications persisted at the 12-month follow-up.

CONCLUSIONS

The disconnection procedure is a safe and effective treatment strategy to treat drug-resistant epilepsy in patients with HHs. With the limitations of initial experience and a short-term follow-up, it appears that the thulium 2-μm laser has the technical features to replace the standard coagulation in this procedure.

Advances in epilepsy surgery

This review summarises exciting recent and forthcoming advances that will impact on the surgical management of epilepsy in the near future. This does not cover the current accepted diagnostic methodologies or surgical treatments that are routinely practiced today. The content of this review was derived from a PubMed literature search, using the key words 'Epilepsy Surgery', 'Neuromodulation', 'Neuroablation', 'Advances', between 2010 and November 2013.

Clinical characteristics and long-term outcome of surgery for hypothalamic hamartoma in children with refractory epilepsy

CONTEXT

Hypothalamic hamartomas (HH) are ectopic masses of neuronal and glial tissue most commonly presenting with medically refractory gelastic seizures with evolution to other seizure types. They are also associated with cognitive and behavioral problems to varying extent. Surgery has been found to improve quality of life in more than 50% of patients.

AIM

To evaluate the clinical characteristics and long-term outcome of surgery in children with HH and refractory epilepsy.

MATERIALS AND METHODS

A retrospective analysis of presurgical, surgical, and postsurgical data of six children who underwent surgery for HH and had at least 3 years follow-up was performed.

RESULTS

SIX CHILDREN (MALE: female = 5:1) aged 3-16 years (at the time of surgery) underwent surgical resection of HH for refractory epilepsy. At last follow-up (range 3-9 years), three children were in Engel's class I, two in Class II, and one in class III outcome. Significant improvement in behavior, quality of life was noted in four children; while the change in intelligence quotient (IQ) was marginal.

CONCLUSIONS

Medically refractory epilepsy associated with behavioral and cognitive dysfunction is the most common presentation of HH. Open surgical resection is safe with favorable outcome of epilepsy in 50% with significant improvement in behavior and marginal change in cognitive functions.

Hypothalamic hamartomas. Part 2. Surgical considerations and outcome

Hypothalamic hamartomas are uncommon developmental heterotopic masses composed of an intermixed array of neurons, glia, and myelinated fibers closely associated with the mammillary bodies. Gelastic seizures, the hallmark feature of hypothalamic hamartomas, commonly present in early childhood. However, patients usually also display a disabling clinical syndrome, which may include various other types of refractory seizures with secondary generalization together with progressive cognitive, behavioral, and psychiatric dysfunction. The hamartoma itself has been unequivocally shown to be intrinsically epileptogenic. Over the past 2 decades there has been considerable effort to develop neurosurgical techniques to treat the epileptic syndrome effectively as well as to improve the neurocognitive and behavioral outcome.

Robotic-arm stereotactic radiosurgery as a definitive treatment for gelastic epilepsy associated with hypothalamic hamartoma

Gelastic seizures, characterised by paroxysms of pathological laughter, are most often associated with an underlying hypothalamic hamartoma. This report describes the definitive treatment using stereotactic-radiosurgery for a teenaged child whose gelastic epilepsy was found refractory to various antiepileptic drugs. Since surgery was not consented to, the child was referred to us for stereotactic radiosurgery (SRS), which was delivered with robotic-arm -SRS to a dose of 30 Gy in five fractions in five consecutive days. A decrease in the frequency of seizures was noticeable as early as within a week, and at 12 months after the procedure, there has been a total cessation of seizures.

The gelastic seizures-hypothalamic hamartoma syndrome: facts, hypotheses, and perspectives

Hypothalamic hamartoma (HH) can be associated with a wide spectrum of epileptic conditions, ranging from a mild form with seizures characterized by urge to laugh and no cognitive involvement up to a catastrophic encephalopathy with early onset gelastic seizures (GS), precocious puberty, and mental retardation. Moreover, a refractory, either focal or generalized, epilepsy develops during the clinical course in nearly all the cases. Neurophysiologic and neuroimaging studies have demonstrated that HH itself generates GS and starts a process of secondary epileptogenesis responsible for refractory focal or generalized epilepsy. The intrinsic epileptogenicity of HH may be explained by the neurophysiological properties of small GABAergic, spontaneously firing HH neurons. Surgical ablation of HH can reverse epilepsy and encephalopathy. Gamma-knife radiosurgery and image-guided robotic radiosurgery seem to be useful and safe approaches for treatment, in particular of small HH. Here, we review this topic, based on literature reports and our personal observations. In addition, we discuss pathogenetic hypotheses and suggest new approaches to this intriguing issue.

Non-resective surgery and radiosurgery for treatment of drug-resistant epilepsy

Epilepsy surgery is an effective treatment for properly selected patients with intractable seizures. However, many patients with medically intractable epilepsy are not excellent candidates for surgical resection of the epileptogenic zone. Due to recent advances in computer technology and bioengineering, several novel techniques are receiving increasing interest for their role in the care of people with epilepsy. Neuromodulation is an emerging surgical option to be used when conventional resective surgery is not indicated. We review the indications and expected outcomes of neuromodulatory treatments currently available for the treatment of refractory epilepsy, i.e., vagus nerve stimulation, deep brain stimulation, stereotactic radiosurgery, and multiple subpial transections.

Predictors of inpatient complications and outcomes following surgical resection of hypothalamic hamartomas

Background:

Our aim was to identify the preoperative factors associated with a greater risk of poor inpatient outcomes in those undergoing resection of hypothalamic hamartomas.

Methods:

We performed a multi-institutional retrospective cohort analysis via the Nationwide Inpatient Sample (1998 – 2007). Patients of any age who underwent resection of hypothalamic hamartomas were identified by ICD-9 coding. The primary outcomes included inpatient complications, length of stay (LOS), and total charges. Multivariate regression models were constructed to analyze the outcomes.

Results:

Two hundred and eighty-two patients were identified with a mean age of 27.7 years, with most being male (53.2%), Caucasian (78.9%), privately insured (69.3%), and treated electively (74.7%) at academic centers (91.7%). A majority (82.2%) had Elixhauser comorbidity scores of < 1, indicating few comorbidities. No inpatient deaths were reported. Mean LOS was 7.39 days and the mean total hospital charges were $53,935. Overall, 19.5% developed an inpatient complication, primarily stroke (16.7%). Female gender, ethnic / racial minorities, higher comorbidity scores, private insurance, and non-academic hospitals were associated with greater LOS and total charges. Private insurance (Odds Ratio, OR: 1.59, P = 0.045) and academic hospitals (OR: 1.43, P = 0.008) were associated with significantly higher odds of any complication. Minority race / ethnicity was associated with a minimal increase in the odds of postoperative stroke (OR: 1.02, P < 0.001) relative to Caucasians.

Conclusions

Through an analysis of a 10-year multi-institutional database, we have described the surgical outcomes of patients undergoing resection of hypothalamic hamartomas. Results demonstrate significant inpatient morbidity, particularly postoperative stroke. Patient- and institution-level factors should be considered in determining the perioperative risk for such patients.

Dose tolerance limits and dose volume histogram evaluation for stereotactic body radiotherapy

Almost 20 years ago, Emami et al. presented a comprehensive set of dose tolerance limits for normal tissue organs to therapeutic radiation, which has proven essential to the field of radiation oncology. The paradigm of stereotactic body radiotherapy (SBRT) has dramatically different dosing schemes but, to date, there has still been no comprehensive set of SBRT normal organ dose tolerance limits. As an initial step toward that goal, we performed an extensive review of the literature to compare dose limits utilized and reported in existing publications. The impact on dose tolerance limits of some key aspects of the methods and materials of the various authors is discussed. We have organized a table of 500 dose tolerance limits of normal structures for SBRT. We still observed several dose limits that are unknown or not validated. Data for SBRT dose tolerance limits are still preliminary and further clinical trials and validation are required. This manuscript presents an extensive collection of normal organ dose tolerance limits to facilitate both clinical application and further research.