Paramedian Supracerebellar Infratentorial Approach for Pontine Cavernoma: 2-Dimensional Operative Video

We describe the case of a 26-yr-old male who presented with headaches, dizziness, and left hemi-hypoesthesia in addition to being COVID-19 positive. The patient was found to have a large hemorrhage in the right dorsolateral pons that was found to be due to a pontine cavernous malformation. The patient underwent a right-sided paramedian supracerebellar infratentorial approach for resection of this lesion with preservation of the developmental venous anomaly. We present the operative video with a specific focus on approach selection, anatomic illustrations, and technical nuances. The literature on the timing of brainstem cavernoma surgery is reviewed.1-4 The patient's postoperative clinical course and postoperative imaging are reviewed. The patient gave informed consent for the procedure and verbal consent for being part of this submission and the publication of their image.

Resection of Pontine Cavernoma Through the Anterior Transpetrosal Approach

The pons is the most frequent local for brain stem cavernoma.1 Repeated hemorrhage of brainstem cavernoma is associated with significant and accumulative neurological deficits and thus requires treatment. According to the Swedish Karolinska’s group of radiosurgery, ”it could not be concluded whether GKRS affects the natural course of a CM. The incidence of radiation-induced complications was approximately seven times higher than that expected.”2 Thus, microsurgical removal has become the mainstay of treatment. In our experience, the following details assist in obtaining favorable outcomes and avoiding postoperative complications3,4: (a) the entry into the cavernoma based on thorough knowledge of the microanatomy; (b) the detailed study of the images and the presentation of the cavernoma on or near the brain stem surface; (c) the resection of the live cavernous hemangioma and not the mere removal of the multiple aged organized hematomas; (d) the preservation of the associated venous angioma; (e) the direct and shortest access to the lesion provided by a skull base approach; and (f) the use of the available technology, such as intraoperative neuromonitoring and neuroimaging. We present the case of a 54-yr-old male with recent deterioration in year 2001, past repetitive episodes of gait imbalance, and speech difficulty over a 7-yr period from known pontine cavernoma. The anterior petrosal approach provided superb and direct exposure to the entry at the lateral pons and the cavernoma was totally removed with preservation of the venous angioma. His preoperative neurological deficit rapidly recovered. Patient consented to the procedure and photography. Images at 3:15 from Kadri et al, The anatomical basis for surgical presercation of temporal muscle. J Neurosurg. 2004;100:517-522, used with permission from JNSPG. Image at 3:27 from Al-Mefty O, Operative Atlas of Meningiomas, © LWW, 1997, with permission.

Holmes tremor: a delayed complication after resection of brainstem cavernomas

OBJECTIVEIn this paper, the authors aimed to illustrate how Holmes tremor (HT) can occur as a delayed complication after brainstem cavernoma resection despite strict adherence to the safe entry zones (SEZs).METHODSAfter operating on 2 patients with brainstem cavernoma at the Great Metropolitan Hospital Niguarda in Milan and noticing a similar pathological pattern postoperatively, the authors asked 10 different neurosurgery centers around the world to identify similar cases, and a total of 20 were gathered from among 1274 cases of brainstem cavernomas. They evaluated the tremor, cavernoma location, surgical approach, and SEZ for every case. For the 2 cases at their center, they also performed electromyographic and accelerometric recordings of the tremor and evaluated the postoperative tractographic representation of the neuronal pathways involved in the tremorigenesis. After gathering data on all 1274 brainstem cavernomas, they performed a statistical analysis to determine if the location of the cavernoma is a potential predicting factor for the onset of HT.RESULTSFrom the analysis of all 20 cases with HT, it emerged that this highly debilitating tremor can occur as a delayed complication in patients whose postoperative clinical course has been excellent and in whom surgical access has strictly adhered to the SEZs. Three of the patients were subsequently effectively treated with deep brain stimulation (DBS), which resulted in complete or almost complete tremor regression. From the statistical analysis of all 1274 brainstem cavernomas, it was determined that a cavernoma location in the midbrain was significantly associated with the onset of HT (p < 0.0005).CONCLUSIONSDespite strict adherence to SEZs, the use of intraoperative neurophysiological monitoring, and the immediate success of a resective surgery, HT, a severe neurological disorder, can occur as a delayed complication after resection of brainstem cavernomas. A cavernoma location in the midbrain is a significant predictive factor for the onset of HT. Further anatomical and neurophysiological studies will be necessary to find clues to prevent this complication.

Assessment of Quality of Life after Surgery in a Patient with Brainstem Cavernoma

Not Available Bang. J Neurosurgery 2020; 10(1): 130-134

Microsurgical resection of medullary cavernoma via the olivary zone by the retrosigmoid supracondylar approach

Microsurgical resection of the medullary cavernoma is rare, comprising less than 15% of more than 250 surgeries of brainstem cavernoma performed by the senior author (H.B.).1 This video demonstrates a case of a cavernous malformation inside the lateral part of the medulla, which was surgically treated via the olivary zone by the retrosigmoid supracondylar approach in a half-sitting position. Osseous drilling of the lateral foramen magnum provided wide exposure of the cerebellomedullary cistern around the olive.2,3 The lesion was completely dissected at the appropriate cleavage plane from the normal parenchyma. The patient developed no new neurological deficits and had no recurrence during 3 years of follow-up after the operation.The video can be found here: https://youtu.be/7i7SccS5HmU.

Endoscope-assisted resection of a brainstem cavernoma

Procedures on cavernous malformations of the brainstem are challenging due to their eloquent location. This accounts especially for recurrent cavernomas as surgical scars, adhesions, and functional shift might have occurred since primary surgery. We report on a 38-year-old female patient with a large recurrent brainstem cavernoma, who underwent previous successful surgery and experienced recurrent bleeding about 2 years later. She harbored a large associated developmental venous anomaly (DVA) traversing the cavernoma through the midline of the brainstem. In order to visualize complete resection and preservation of the DVA at the same time, endoscopic-assisted resection within the brainstem after decompression in the semisitting position was performed.The video can be found here: https://youtu.be/K1p-Sx7jUpA.

Resection of brainstem cavernous malformation via perifacial zone through retrosigmoid supracondylar approach

Hemorrhagic brainstem cavernous malformations carry a high risk of progressive neurological deficits owing to recurrent hemorrhages and hence require complete surgical resection while minimizing damage to the dense concentration of nuclei and fibers inside the brainstem. To access lesions inside the lower pons, the senior author (H.B.) has preferred to approach the lesions via the “perifacial zone” through the pontomedullary sulcus from the inferior surface of the pontine bulge for more than 20 years.1,2 This video demonstrates a case of a cavernous malformation inside the lower pons, which was surgically treated via the pontomedullary junction through the retrosigmoid supracondylar approach in a half-sitting position. The lesion was completely removed in piecemeal fashion through a tiny incision on the sulcus, which did not cause any new neurological deficits. The modified Rankin Scale improved from 4 before the surgery to 1, and the patient had no recurrence during the 2 years of follow-up. The advantage of this access and the dissection techniques for this challenging lesion are introduced, based on our experience with more than 230 surgeries of brainstem cavernoma.The video can be found here: https://youtu.be/0H_XqkQgQ9I.