Contralateral interhemispheric resection of thalamic cavernous malformations with frameless stereotaxy

Contralateral Interhemispheric Transcallosal Approach for Thalamic Cystic Cavernous Malformation

A 42-year-old man presented with a headache and right hemiparesis and was found to have a cystic mass with a calcified mural nodule in the left thalamus. Because the thalamus is surrounded by vital neurovascular structures, the surgical approach to thalamic lesions can be challenging. We decided to remove the mass for decompression and pathological diagnosis. The mass was removed through a contralateral interhemispheric transcallosal transchoroidal approach with less retraction and parenchymal injury than other approaches to avoid brain retraction and cortical injury. The pathological diagnosis was cavernous malformation. Temporary worsening of the preoperative hemiparesis was recovered over two months following surgery. Tolerable thalamic pain syndrome remained. Here, we report a rare case of thalamic cavernous malformation with a favorable outcome through a contralateral surgical approach.

Thalamic cavernous malformations

Cavernous malformations of the thalamus represent a particularly complex subset of cavernous malformations because of the highly eloquent nature of the involved tissue and their deep location. The decision about whether to operate on any individual lesion depends on the specific location of the lesion within the thalamus, the nature of the patient's symptoms, and the patient's history. When surgery is recommended, the approach must be chosen carefully. Each part of the thalamus is reached by a different surgical approach. These approaches include the orbitozygomatic approach to the anteroinferior thalamus, the anterior interhemispheric transcallosal approach to the medial thalamus, the anterior contralateral interhemispheric transcallosal approach to the lateral thalamus, the posterior interhemispheric transcallosal approach to the posterosuperior thalamus, the parieto-occipital transventricular approach to the lateral posteroinferior thalamus, and the suboccipital supracerebellar infratentorial/transtentorial approach to the medial posteroinferior thalamus. Careful attention to safe entry zones and image guidance can allow safe removal of these lesions when necessary.

Transulcal parafascicular minimally invasive approach to deep and subcortical cavernomas: technical note

Cavernomas comprise 8%-15% of intracranial vascular lesions, usually supratentorial in location and superficial. Cavernomas in the thalamus or subcortical white matter represent a unique challenge for surgeons in trying to identify and then use a safe corridor to access and resect the pathology. Previous authors have described specific open microsurgical corridors based on pathology location, often with technical difficulty and morbidity. This series presents 2 cavernomas that were resected using a minimally invasive approach that is less technically demanding and has a good safety profile. The authors report 2 cases of cavernoma: one in the thalamus and brainstem with multiple hemorrhages and the other in eloquent subcortical white matter. These lesions were resected through a transulcal parafascicular approach with a port-based minimally invasive technique. In this series there was complete resection with no neurological complications. The transulcal parafascicular minimally invasive approach relies on image interpretation and trajectory planning, intraoperative navigation, cortical cannulation and subcortical space access, high-quality optics, and resection as key elements to minimize exposure and retraction and maximize tissue preservation. The authors applied this technique to 2 patients with cavernomas in eloquent locations with excellent outcomes.

CAVERNOUS MALFORMATIONS OF THE BASAL GANGLIA AND THALAMUS

CAVERNOUS MALFORMATIONS OF the basal ganglia and thalamus present a unique therapeutic challenge to the neurosurgeon given their unclear natural history, the risk of surgical treatment, and the unproven efficacy of radiosurgical therapy. Via a PubMed search of the English and French literature, we have systematically reviewed the natural history and surgical and radiosurgical management of these lesions reported through April 2008. Including rates cited for “deep” cavernous malformations, annual bleeding rates for these lesions varied from 2.8% to 4.1% in the natural history studies. Across surgical series providing postoperative or long-term outcome data on 103 patients, we found an 89% resection rate, a 10% risk of long-term surgical morbidity, and a 1.9% risk of surgical mortality. The decrease in hemorrhage risk reported 2 years after radiosurgery might be a result of natural hemorrhage clustering, underscoring the unproven efficacy of this therapeutic modality. Given the compounded risks of radiation-induced injury and post-radiosurgical rebleeding, radiosurgery at modest dosimetry (12–14 Gy marginal doses) is only an option for patients with surgically inaccessible, aggressive lesions.

Cavernomes profonds (corps calleux, intraventriculaires, ganglions de la base, insulaires) et du tronc cérébral. Expérience d'une série brésilienne

With a review of the literature, we report our experience with surgical treatment of deep-seated cavernomas (intraventricular, of the corpus callosum, the capsula interna, the insula and the brain stem). Outcome was good in all nine patients after surgery for deep-seated brain cavernomas. There we also 13 cases of the brain stem cavernomas treated surgically. Of them, nine patients were stabilized or improved, one patient worsened, one patient died and two were lost to follow-up. Whatever the location, surgery should only concern symptomatic or hemorrhagic lesions close to the pia-matter or the ependyma as well as those covered by a thin layer of parenchyma. Neuronavigation and microsurgical procedures are essential in the treatment of deep-seated cavernomas.