MRI-Guided Interstitial Laser Ablation for Intracranial Lesions: A Large Single-Institution Experience of 133 Cases.

BACKGROUND: Managing difficult-to-access lesions or surgically accessible lesions in fragile patients is a central problem in neurosurgery. MRI-guided interstitial laser ablation (ILA) is a minimally invasive option that may provide a safe means of treating these challenging patients. OBJECTIVE: We aim to (1) evaluate safety, efficacy, and preliminary outcomes within a diverse and large series of ILA treatments; and (2) report technical details and operative trends that proved useful over time in the authors' experience and that may be of use to neurosurgeons who perform ILA. METHODS: A retrospective evaluation of ILA patients was performed in terms of demographics, surgical techniques, and clinical outcomes. RESULTS: A total of 133 intracranial lesions in 120 patients were treated with ILA, including glioblastomas (GBM), other gliomas, metastases, epilepsy foci, and radionecrosis. The rate of complications/unexpected readmission was 6.0%, and the mortality rate was 2.2%. With high-grade tumors, tumor volumes >3 cm in diameter trended toward a higher rate of complication (p = 0.056). Median progression-free survival (PFS) and overall survival (OS) for recurrent GBM were 7.4 and 11.6 months, respectively. As a frontline treatment for newly diagnosed GBM, median PFS and OS were 5.9 and 11.4 months, respectively. For metastases, median PFS was not yet reached, and OS was 17.2 months. CONCLUSION: Our series suggests that ILA is a safe and efficacious treatment for a variety of intracranial pathologies, can be tailored to treat difficult-to-access lesions, and may offer a novel alternative to open craniotomy in properly selected patients.

Laser interstitial thermal therapy for subependymal giant cell astrocytoma: technical case report.

Subependymal giant cell astrocytoma (SEGA) is a rare tumor occurring almost exclusively in patients with tuberous sclerosis complex. Although open resection remains the standard therapy, complication rates remain high. To minimize morbidity, less invasive approaches, such as endoscope-assisted resection, radiosurgery, and chemotherapy with mTOR pathway inhibitors, are also used to treat these lesions. Laser interstitial thermal therapy (LITT) is a relatively new modality that is increasingly used to treat a variety of intracranial lesions. In this report, the authors describe two pediatric cases of SEGA that were treated with LITT. In both patients the lesion responded well to this treatment modality, with tumor shrinkage observed on follow-up MRI. These cases highlight the potential of LITT to serve as a viable minimally invasive therapeutic approach to the management of SEGAs in the pediatric population.

Utilizing personalized stereotactic frames for laser interstitial thermal ablation of posterior fossa and mesiotemporal brain lesions: a single-institution series.

OBJECTIVE The precision of laser probe insertion for interstitial thermal therapy of deep-seated lesions is limited by the method of stereotactic guidance. The objective of this study was to evaluate the feasibility of customized STarFix 3D-printed stereotactic platforms to guide laser probe insertion into mesiotemporal and posterior fossa targets. METHODS The authors conducted a retrospective review of 5 patients (12-55 years of age) treated with laser interstitial thermal therapy (LITT) in which STarFix platforms were used for probe insertion. Bone fiducials were implanted in each patient's skull, and subsequent CT scans were used to guide the design of each platform and incorporate desired treatment trajectories. Once generated, the platforms were mounted on the patients' craniums and used to position the laser probe during surgery. Placement of the laser probe and the LITT procedure were monitored with intraoperative MRI. Perioperative and follow-up MRI were performed to identify and monitor changes in target lesions. RESULTS Accurate placement of the laser probe was observed in all cases. For all patients, thermal ablation was accomplished without intraoperative complications. Of the 4 patients with symptomatic lesions, 2 experienced complete resolution of symptoms, and 1 reported improved symptoms compared with baseline. CONCLUSIONS Customized stereotactic platforms were seamlessly incorporated into the authors' previously established LITT workflow and allowed for accurate treatment delivery.

Characterization of postoperative fevers after hemispherotomy.

OBJECTIVE: Patients who have undergone hemispherotomy for intractable epilepsy tend to develop postoperative fevers, which can be severe and/or prolonged, for unclear reasons. The purpose of this paper is to characterize postoperative fever curves after hemispherotomy based on factors including seizure etiology, perioperative blood loss, and the presence or absence of ventricular drainage. METHODS: We present 72 patients who underwent hemispherotomy at our institution between 1995 and 2013 by four surgeons. Data including daily maximum body temperature, seizure etiology, ventricular drain use, steroid and antipyretic use, and seizure control were gathered retrospectively based on electronic records including operative summaries, nursing notes, discharge summaries, and follow-up clinic notes. RESULTS: Seventy-two patients from 11 weeks to 21 years old (mean 7.4 years old) underwent hemispherotomy between 1995 and 2013. Sixty (83%) had fevers postoperatively, while the remainder were afebrile. Patients without external ventricular drains had higher and more prolonged fevers compared to those with drains (p = 0.003). Patients with Rasmussen's encephalitis tended to have higher postoperative fevers than patients with other seizure etiologies (p = 0.005), while patients with cortical dysplasia and polymicrogyria tended to have less severe fevers (p = 0.027 and 0.017, respectively). Fifty-five patients (76%) had freedom from disabling seizures (Engel class I), and 96% showed worthwhile improvement or better (Engel classes I-III). CONCLUSION: Postoperative fever can be anticipated in hemispherotomy patients, may vary based on certain seizure etiologies, and may be mitigated by routinely utilizing external ventricular drainage. Hemispherotomy is an effective surgical procedure for intractable epilepsy in selected patients.

Microsurgical confirmation of perforating arteries arising from the fundus of a posterior communicating artery aneurysm.

Perforating arteries rarely project from the fundus of an aneurysm. We present the case of a 35-year-old woman who was found to have a right posterior communicating artery (PCOM) aneurysm via catheter angiography. Superselective microcatheter angiography revealed that perforating arteries arose from the aneurysm fundus that supplied the anterolateral thalamus. Microsurgical exploration confirmed several small perforating arteries arising from the aneurysm dome as well as an atretic distal PCOM artery. Given the complex anatomy, the lesion was unsuitable for clipping. We propose that this aneurysm represents a developmental variant whereby the proximal PCOM artery becomes atretic and terminates in PCOM perforators. The video can be found here: http://youtu.be/iDcp9fsDjq4.

The safety of aeroplane travel in patients with symptomatic carotid occlusion.

OBJECTIVE: Patients with carotid stenosis or occlusion may be at increased risk for stroke during air travel. Records from the Carotid Occlusion Surgery Study (COSS), a randomised trial of surgical revascularisation for complete carotid artery occlusion and haemodynamic ischaemia, were examined for evidence of stroke related to air travel. METHODS: COSS subjects who travelled by aeroplane to a regional Positron Emission Tomography (PET) centre for a screening of cerebrovascular haemodynamic evaluation were identified. Maximum altitude and total flight time were estimated based on the distance between origin and destination. Ischaemic events were determined by a structured telephone interview within 24 h of travel. Patient demographics, comorbidities, oxygen extraction fraction (OEF) data and 24 h interview responses were recorded. RESULTS: Seventy-seven patients with symptomatic carotid occlusion travelled by aeroplane to a single PET centre (174 flights). Fifty-two (67.5%) were men and 25 (32.5%) were women. The average age was 58.7±1.4 years. Twenty-seven patients (35.1%) demonstrated evidence of ipsilateral haemodynamic cerebral ischaemia as measured by PET OEF, while 50 (64.9%) had normal OEF. Patients flew an average distance of 418.9±25.9 miles for 107.1±4.7 min per trip. No patient reported symptoms of a transient ischaemic attack or stroke during or within 24 h after aeroplane travel (95% CI 0% to 2.0%). CONCLUSIONS: The risk of stroke as a consequence of air travel is low, even in a cohort of patients at high risk for future stroke owing to haemodynamic impairment. These patients with symptomatic carotid occlusion should not be discouraged from air travel.

Isolated recurrence of acute myeloid leukemia in the cerebellum: illustrative case.

BACKGROUND: Myeloid sarcoma is a rare malignant hematopoietic neoplasm that arises at extramedullary sites. Although myeloid sarcoma may involve any organ, central nervous system (CNS) involvement is exceptionally rare. To date, few case reports and case series have described CNS myeloid sarcoma, the majority of which include peripheral disease. OBSERVATIONS: The authors present an illustrative case of an adult male with acute myeloid leukemia (AML) in remission relapsing with an isolated, diffuse myeloid sarcoma of the cerebellum. Magnetic resonance imaging showed posterior fossa crowding and diffuse enhancement within the cerebellar white matter without an apparent mass lesion. The patient required ventriculostomy due to obstructive hydrocephalus and ultimately suboccipital craniectomy with duraplasty due to posterior fossa compression. An open cerebellar biopsy revealed myeloid sarcoma. Peripheral studies did not meet the criteria for recurrent AML. The patient subsequently received high-dose systemic chemotherapy and has responded well to treatment. LESSONS: Myeloid sarcoma may be a neurosurgical lesion because it has the potential to cause mass effect with obstructive hydrocephalus requiring emergent cerebrospinal fluid diversion and possible decompression. The authors report a rare case of isolated recurrence of AML in the form of diffuse CNS myeloid sarcoma and describe the role of neurosurgery in its diagnosis and treatment.

Glioblastoma Treated With Magnetic Resonance Imaging-Guided Laser Interstitial Thermal Therapy: Safety, Efficacy, and Outcomes.

BACKGROUND: Despite the multitude of available treatments, glioblastoma (GBM) remains an aggressive and uniformly fatal tumor. Laser interstitial thermal therapy (LITT) is a novel, minimally invasive treatment that holds promise for treating patients with GBM who are not candidates for traditional open craniotomy. However, due to the recent introduction of LITT into clinical practice, large series that evaluate safety and long-term outcomes after LITT are lacking. OBJECTIVE: To present our institution's series of over 50 GBM patients treated with LITT, with regard to safety, efficacy, and outcomes. METHODS: We performed a retrospective descriptive study of patients with histologically proven GBM who underwent LITT. Data collected included demographics, tumor location and volume, tumor genetic markers, treatment volume, perioperative complications, and long-term follow-up data. RESULTS: We performed 58 LITT treatments for GBM in 54 patients over 5.5 yr. Forty-one were recurrent tumors while 17 were frontline treatments. Forty GBMs were lobar in location, while 18 were in deep structures (thalamus, insula, corpus callosum). Average tumor volume was 12.5 ± 13.4 cm3. Average percentage of tumor treated with the yellow thermal damage threshold (TDT) line (dose equivalent of 43°C for 2 min) was 93.3% ± 10.6%, and with the blue TDT line (dose equivalent of 43°C for 10 min) was 88.0% ± 14.2%. There were 7 perioperative complications (12%) and 2 mortalities (3.4%). Median overall survival after LITT for the total cohort was 11.5 mo, and median progression-free survival 6.6 mo. CONCLUSION: LITT appears to be a safe and effective treatment for GBM in properly selected patients.

Initial Experience Using Intraoperative Magnetic Resonance Imaging During a Trans-Sulcal Tubular Retractor Approach for the Resection of Deep-Seated Brain Tumors: A Case Series.

BACKGROUND: Treatment of deep-seated subcortical intrinsic brain tumors remains challenging and may be improved with trans-sulcal tubular brain retraction techniques coupled with intraoperative magnetic resonance imaging (iMRI). OBJECTIVE: To conduct a preliminary assessment of feasibility and efficacy of iMRI in tubular retractor-guided resections of intrinsic brain tumors. METHODS: Assessment of this technique and impact upon outcomes were assessed in a preliminary series of brain tumor patients from 2 centers. RESULTS: Ten patients underwent resection with a tubular retractor system and iMRI. Mean age was 53.2 ± 9.0 yr (range: 37-61 yr, 80% male). Lesions included 6 gliomas (3 glioblastomas, 1 recurrent anaplastic astrocytoma, and 2 low-grade gliomas) and 4 brain metastases (1 renal cell, 1 breast, 1 lung, and 1 melanoma). Mean maximal tumor diameter was 2.9 ± 0.95 cm (range 1.2-4.3 cm). The iMRI demonstrated subtotal resection (STR) in 6 of 10 cases (60%); additional resection was performed in 5 of 6 cases (83%), reducing STR rate to 2 of 10 cases (20%), with both having tumor encroaching on eloquent structures. Seven patients (70%) were stable or improved neurologically immediately postoperatively. Three patients (30%) had new postoperative neurological deficits, 2 of which were transient. Average hospital length of stay was 3.4 ± 2.0 d (range: 1-7 d). CONCLUSION: Combining iMRI with tubular brain retraction techniques is feasible and may improve the extent of resection of deep-seated intrinsic brain tumors that are incompletely visualized with the smaller surgical exposure of tubular retractors.

Management of Intracranial Metastatic Disease With Laser Interstitial Thermal Therapy.

Treatment approaches for metastatic brain tumors continue to evolve, with increasing recent emphasis on focal therapies whenever possible. MRI-guided Laser Interstitial Thermal Therapy (LITT) is a minimally invasive surgical option that has broadened the capability of the neurosurgeon in treating difficult-to-treat intracranial lesions. This technology uses image-guided delivery of laser to the target lesion to generate heat and thereby ablate pathological tissue and has expanded the neurosurgical armamentarium for surgical treatment of brain metastases. In this study, we describe the indications for LITT in the management of intracranial metastatic disease and report our institutional experience with LITT.

Hydrocephalus presenting as idiopathic aqueductal stenosis with subsequent development of obstructive tumor: report of 2 cases demonstrating the importance of serial imaging.

The authors describe 2 cases of triventricular hydrocephalus initially presenting as aqueductal stenosis that subsequently developed tumors of the pineal and tectal region. The first case resembled late-onset idiopathic aqueductal stenosis on serial imaging. Subsequent imaging revealed a new tumor in the pineal region causing mass effect on the midbrain. The second case presented in a more typical pattern of aqueductal stenosis during infancy. On delayed follow-up imaging, an enlarging tectal mass was discovered. In both cases hydrocephalus was successfully treated by cerebrospinal fluid diversion prior to tumor presentation. The differential diagnoses, diagnostic testing, and treatment course for these unusual cases are discussed. The importance of follow-up MRI in cases of idiopathic aqueductal stenosis is emphasized by these exemplar cases.

Initial experience with Penumbra Coil 400 versus standard coils in embolization of cerebral aneurysms: a retrospective review.

BACKGROUND AND PURPOSE: The Penumbra Coil 400 System (PC 400) is the newly introduced platinum coil system designed specifically to enhance filling efficiency by increasing coil diameter. Our goal was to study the packing and treatment advantage of the PC 400's unique geometric configuration compared with conventional coils (controls). MATERIALS AND METHODS: 16 aneurysms embolized with the PC 400 in 2011 were compared with 79 equally matched aneurysms embolized with conventional coils from 2004 to 2011. Primary outcomes assessed were acute packing density, embolization time, and the number of coils required for aneurysm occlusion. RESULTS: Aneurysm embolization with the PC 400 achieved a higher packing density (36.8% vs 28.1%; p<0.005) and with fewer coils (an average of 3.9 vs 6.1 coils per aneurysm; p<0.05). In addition, the total procedural time for the subjects treated with the PC 400 was significantly less (45.7 vs 64.1 min; p<0.05). There were no procedural complications associated with the PC 400. CONCLUSIONS: Compared with conventional coils, the PC 400 is more efficient in the embolization of cerebral aneurysms, achieving greater packing density with fewer coils and less time without compromising safety.