The Brainstem Cavernoma Case Series: A Formula for Surgery and Surgical Technique

Giant pediatric brainstem cavernoma: illustrative case

BACKGROUND

Cerebral cavernous malformations are low-flow vascular lesions and the most common of all vascular pathologies encountered by neurosurgeons. The location of these lesions is critically important in determining the symptomatology and whether intervention is indicated. Cavernous malformations localized to the brainstem are often the most complex of these to manage given the density of critical structures and tracts found within the brainstem.

OBSERVATIONS

Here, the authors present the case of a 3-year-old male who presented with hemiparesis and eventually developed hydrocephalus from a giant brainstem cavernous malformation. The patient initially did well on steroids but had a recurrent hemorrhage that led to worsening hemiparesis and hydrocephalus. The authors then elected to resect the cavernous malformation via a supracerebellar infratentorial approach utilizing intraoperative MRI to ensure complete resection. Postoperatively, the patient returned to near baseline neurological function.

LESSONS

The authors describe an uncommon approach to the management of a pediatric patient with a giant brainstem cavernous malformation by carefully examining the potential approaches and utilizing available technologies to ensure an excellent outcome for the patient. https://thejns.org/doi/10.3171/CASE24814.

Cerebellar Cavernoma Resection: Case Report with Long-Term Follow-Up

Background: Cerebral cavernous malformations (CCMs), particularly when located in the cerebellum, pose unique clinical challenges due to the risk of hemorrhage and proximity to critical neurovascular structures. Surgical resection is often necessary to prevent further neurological deterioration. This case report describes the management of a symptomatic cerebellar cavernoma, emphasizing the use of microsurgical techniques and long-term follow-up. The objective of this study is to illustrate the surgical approach and outcomes of a patient with a hemorrhagic cerebellar cavernoma. Methods: A 63-year-old female presented with vertigo, and neuroimaging revealed a hemorrhagic cavernous malformation located in the right cerebellar hemisphere. Follow-up was conducted at two months and one year postoperatively, with serial imaging to assess lesion recurrence and neurological recovery. Results: Complete resection of the cavernoma was achieved without postoperative neurological deficits. Imaging at two months and one year post-surgery showed no signs of recurrence or new lesion formation. The patient remained asymptomatic, with no cranial nerve deficits or other long-term complications. Conclusions: This case demonstrates the effectiveness of microsurgical resection in treating symptomatic cerebellar cavernomas. The use of advanced intraoperative tools, such as neuronavigation and IONM, contributed to the successful outcome and prevention of postoperative complications. Long-term follow-up remains crucial to monitor for recurrence or the development of de novo lesions.

A novel method of neurophysiological brainstem mapping in neurosurgery

BACKGROUND

Brainstem mapping with electrical stimulation allows functional identification of neural structures during resection of deep lesions. Single pulses or train of pulses are delivered to map cranial nerves and corticospinal tracts, respectively.

NEW METHOD

We introduce a hybrid stimulation technique for mapping the brainstem. The stimulus consists of an electrical single pulse followed by a short train of 3-5 pulses at 500 Hz, at an interval of 60-75 ms. The responses to this stimulation pattern are recorded from appropriate cranial and limb muscles.

RESULTS

Both the single pulse and the short train elicit electromyographic responses when motor fibers or motor nuclei of the cranial nerves are stimulated. Responses to the train but not to the preceding single pulse indicate activation of the descending motor tracts, in the mesencephalon and the pons. Conversely, in the medulla, limb responses to stimulation of the corticospinal tracts are elicited by a single pulse. Identification of the extra and intra-axial courses of the trigeminal motor and sensory fibers is possible by recording responses from the masseter and the tongue muscles.

COMPARISON WITH EXISTING METHOD(S)

To date, either a pulse or a train is delivered during brainstem mapping, switching from one to the other modality according to the expected target structure. This procedure can be time-consuming and may even lead to false negative responses to the stimulation, eventually leading to inaccurate neurosurgical procedures.

CONCLUSIONS

The novel hybrid pulse-train technique enhances the advantage of brainstem mapping procedure, minimizing pitfalls and improving patient safety.