Transcallosal Anterior Interforniceal Approach for Removal of Superior Midbrain Cavernous Malformations in Children: A Retrospective Series of 10 Cases in a Single Center

Balloon-Assisted Corpus Callosotomy. Reducing the Impact of Transcallosal Approaches

BACKGROUND

The interhemispheric transcallosal approach is widely used to remove intraventricular lesions. Corpus callosotomy gives immediate access to the ventricular chambers but is invasive in nature. Loss of callosal fibers, although normally tolerate, may cause disturbances ranging from a classical disconnection syndrome up to minor neuropsychological changes.

OBJECTIVE

To open an operative window in the corpus callosum through separation rather than disconnection of the white matter fibers.

METHODS

In 7 patients undergoing the interhemispheric transcallosal approach for intraventricular lesions, lying around or below the foramen of Monro, a stoma was created within the corpus callosum by using a 4F Fogarty catheter. The series included 3 colloid of the third ventricle, 2 thalamic cavernomas, 1 subependymoma, and 1 ependymoma of the foramen of Monro. We illustrate the technique and the clinico-radiological outcome, focusing on the size of callosotomy as seen on postoperative MRI.

RESULTS

The balloon-assisted corpus callosotomy provided a circular, smooth-walled access to the ventricular chambers, which allowed uncomplicated removal of the lesions. On postoperative MRI, the size of the callosotomy shrinked compared with surgery (2.8-6.4 mm at follow-up vs 6-9 mm as measured intraoperatively). No signs of disconnection syndrome or new permanent deficits were observed in this series.

CONCLUSION

The balloon-assisted technique produces a small callosotomy, without clinical consequences, showing a self-closing trend on postoperative MRI. This technique is a rewarding tool to reduce the impact of callosotomy while keeping the advantages of microsurgical interhemispheric approaches.

Surgical Approaches to the Third Ventricle: An Update

The third ventricle is located in the deepest part of the brain and is delimited by both telencephalic and diencephalic structures. Its location makes every surgical procedure inside or around it quite challenging, due to the distance from the surface to the fragility of the neurovascular structures that is necessary to dissect before entering its cavity and to the narrow surgical corridors through which it is necessary to work. Its geometric localization inside the cranial cavity and the anatomical relationship with the interhemispheric fissure offers nevertheless to the surgeon an impressive variety of surgical approaches, which allow to reach every millimeter of the third ventricle lumen. Mastering properly all these approaches requires an impressive anatomical knowledge, the best available technology, and most refined technical skills, making the surgery of the third ventricle a point of excellence in the evolution of each neurosurgeon. The development of neuronavigation and neuroendoscopy has been a revolution in neurosurgery in the last 20 years and offered special advantages for the surgery of the third ventricle. In fact, the narrow corridors of approach make the precision of the neuronavigation and the enlightenment and magnification of the neuroendoscopy especially useful to reach the third ventricle cavity and working inside or around it. This chapter reviews the history of the surgery of the third ventricle and offers an update of the variety of surgical corridors identified and of the technology now available to properly work through them and inside the third ventricle cavity.

A Case of Cavernous Malformation of the Midbrain Removed via an Interhemispheric Transcallosal Subchoroidal Approach

Cavernous malformations of the midbrain have a higher rate of hemorrhage and a poorer prognosis than vascular malformations of other brain areas. Surgical resection of these lesions is often necessary to avoid neurological deficits in affected patients. Herein, the literature surrounding cavernous malformations was examined, and the case of a 48-year-old man with left hemiparesis and diplopia caused by incomplete right oculomotor nerve palsy, who was diagnosed with a hemorrhage from a midbrain cavernous malformation, was discussed. The lesion expanded gradually on magnetic resonance imaging and was symptomatic; radical removal of the lesion before the onset of irreversible symptoms due to recurring bleeding was therefore considered to be beneficial for the patient. Surgical removal of the entire cavernous malformations of the midbrain was performed using an interhemispheric transcallosal subchoroidal approach, with excellent postoperative results and complete recovery from the oculomotor nerve palsy and left hemiparesis. This case shows that this approach is the most appropriate for surgical resections of lesions in the upper midbrain.

Pediatric brainstem cavernous malformations: 2-center experience in 40 children

OBJECTIVE

Brainstem cavernous malformations (BSCMs) are relatively uncommon, low-flow vascular lesions in children. Given the paucity of data, guidelines regarding the clinical management of BSCMs in children are lacking and the surgical indication is most commonly based on an individual surgeon's judgment and experience. The goal in this study was to evaluate the clinical behavior of BSCMs in childhood and the long-term outcome in children managed conservatively and surgically.

METHODS

This was an observational, retrospective study including all children with BSCMs who were followed at 2 institutions between 2008 and 2020.

RESULTS

The study population consisted of 40 children (27 boys, 67.5%) with a mean age of 11.4 years. Twenty-three children (57.5%) were managed conservatively, whereas 17 children (42.5%) underwent resection of BSCMs. An aggressive clinical course was observed in 13 children (32.5%), who experienced multiple hemorrhages with a progressive pattern of neurological decline. Multiple BSCMs were observed in 8 patients, of whom 3 patients presented with a complex of multiple tightly attached BSCMs and posed a significant therapeutic challenge. The overall long-term outcome was favorable (modified Rankin Scale [mRS] scores 0-2) in 36 patients (90%), whereas an unfavorable outcome (mRS scores 3 and 4) was seen in 4 children (10%). An mRS score of 5 or 6 was not observed. The mean (± SD) follow-up was 88.0 (± 92.6) months.

CONCLUSIONS

The clinical course of BSCMs in children is highly variable, with benign lesions on the one hand and highly aggressive lesions with repetitive hemorrhages on the other. Given the greater life expectancy and the known higher functional recovery in children, surgical treatment should be considered early in young patients presenting with surgically accessible lesions and an aggressive clinical course, and it should be performed in a high-volume center.

Presentation and management of nervous system cavernous malformations in children: A systematic review and case report

Cerebral cavernous malformations (CMs) are slow-flow vascular lesions that affect up to 0.5% of the pediatric population. These lesions are at risk for hemorrhage, causing seizures, and leading to neurological deficits. Here, we conduct a literature review and then present a report of a supratentorial CM in a 2-year-old patient with no significant past medical history who presented at our institution with 1 month of eye twitching. We performed a literature search of five databases of all articles published before 2020. Our inclusion criteria included cohort and case series of children with mean age under 12 years. Our search yielded 497 unique articles, of which 16 met our inclusion criteria. In our pooled literature analysis, a total of 558 children were included, 8.3% of which had a positive family history and 15.9% had multiple CMs. About 46.1% of the children had seizures, and 88.4% of those who underwent surgery had a total resection. About 85.1% of those with epilepsy were Engel Class 1 postsurgery. Over a mean follow-up of 4.1 years, 3.4% of patients had additional neurological deficits, including paresis and speech deficits. Our analysis of published literature shows surgical intervention should be considered first-line therapy for patients who are symptomatic from CM, present with seizure, and have surgically accessible lesions. Additional work is needed on outcomes and long-term effects of minimally invasive treatments, including radiosurgery and laser ablation, in pediatric populations.

Trans-lamina terminalis suprategmental approach for ventral midbrain lesions: Technical note

Surgical resection of lesions located in the ventral midbrain is challenging. Few approaches and safe entry zones (SEZs) have been proposed and used to remove this type of lesion, and each has its limitations. Using two illustrating cases, the authors describe a trans-lamina terminalis suprategmental approach for removing ventral midbrain lesions. This approach provides a straight surgical trajectory with sparse neurovascular structures and can be performed with a standard pterional or subfrontal craniotomy. It may be the ideal approach for ventromedial midbrain lesions extending towards the third ventricle.