Timing of Surgery and Surgical Strategies in Symptomatic Brainstem Cavernomas: Review of the Literature

Brainstem cavernous hemangioma with improvement of Holmes tremor on excision

An 8-year-old boy presenting with left-angle paralysis, tremor in upper and lower extremities, and diplopia was diagnosed with hemorrhage from a mesencephalic cavernous hemangioma. He underwent hemangiomectomy through the occipital transtentorial approach 4 weeks post-hemorrhage, after which Holmes tremor (HT) markedly reduced. A year later, hemangioma has not recurred; he is now independent in his daily activities. Early intervention in the subacute stage allows for the complete removal of brainstem cavernomas (BSCs), with minimal risk of complications or sequelae. Proper timing and surgical approach for BSCs can prevent re-bleeding and improve HT after an initial hemorrhage, without any lasting negative consequences.

Hyperintense Perilesional Edema on T1-Weighted Imaging in Cavernoma: A Case Report

Cavernoma, also called a cavernous malformation, is a vascular malformation that happens during development. It tends to look like a berry-shaped lesion. In cerebral hemorrhagic cavernous malformations (cavernoma), T1-weighted imaging that shows hyperintense perilesional edema in brain masses is an unusual radiological finding. This sign's association with cavernoma is gaining prominence. We present the case of a 35-year-old female patient without significant medical history who reported a seven-day history of left-side weakness that began in the upper limb, progressed to the lower limb, and was associated with nausea. The non-contrast T1- T1-weighted images displayed a gradient of hyperintense content of the lesion with surrounding relatively hyperintense perilesional edema. The patient consequently underwent surgery to evacuate the hematoma and excise the lesion, which went uneventfully.

Case report: Delayed outflow obstruction of a DVA: A rare complication of brainstem cavernoma surgery

Introduction

Developmental venous anomalies (DVAs) are considered variants of normal transmedullary veins. Their association with cavernous malformations is reported to increase the risk of hemorrhage. Expert consensus recommends meticulous planning with MR imaging, use of anatomical “safe zones”, intraoperative monitoring of long tracts and cranial nerve nuclei, and preservation of the DVA as key to avoiding complications in brainstem cavernoma microsurgery. Symptomatic outflow restriction of DVA is rare, with the few reported cases in the literature restricted to DVAs in the supratentorial compartment.

Case

We present a case report of the resection of a pontine cavernoma complicated by delayed outflow obstruction of the associated DVA. A female patient in her 20's presented with progressive left-sided hemisensory disturbance and mild hemiparesis. MRI revealed two pontine cavernomas associated with interconnected DVA and hematoma. The symptomatic cavernoma was resected via the infrafacial corridor. Despite the preservation of the DVA, the patient developed delayed deterioration secondary to venous hemorrhagic infarction. We discuss the imaging and surgical anatomy pertinent to brainstem cavernoma surgery, as well as the literature exploring the management of symptomatic infratentorial DVA occlusion.

Conclusion

Delayed symptomatic pontine venous congestive edema is extremely rare following cavernoma surgery. DVA outflow restriction from a post-operative cavity, intraoperative manipulation, and intrinsic hypercoagulability from COVID-10 infection are potential pathophysiological factors. Improved knowledge of DVAs, brainstem venous anatomy, and “safe entry zones” will further elucidate the etiology of and the efficacious treatment for this complication.

Long-term outcomes after surgery for brainstem cavernous malformations: analysis of 46 consecutive cases

OBJECTIVE

The objective of this study was to evaluate the long-term outcomes after resection of brainstem cavernous malformations (BSCMs) and to assess the usefulness of the Lawton grading system in these cases.

METHODS

This retrospective study analyzed 46 consecutive patients with BSCMs operated on between July 1990 and December 2020. Outcomes at the last follow-up were defined as favorable (modified Rankin Scale [mRS] score 0-2) or unfavorable (mRS score > 2).

RESULTS

The study cohort comprised 24 men (52%) and 22 women (48%), ranging in age from 8 to 78 years old (median 37 years). In 19 patients (41%), the preoperative mRS score was > 2. All patients had hemorrhagic BSCM. There were 12 (26%) mesencephalic, 19 (41%) pontine, 7 (15%) medullary, and 8 (17%) cerebellar peduncle lesions, with a maximal diameter ranging from 5 to 40 mm (median 15 mm). In total, 24 BSCMs (52%) had bilateral extension crossing the brainstem midline. Lawton grades of 0, I, II, III, IV, V, and VI were defined in 3 (7%), 2 (4%), 10 (22%), 11 (24%), 8 (17%), 7 (15%), and 5 (11%) cases, respectively. Total resection of BSCMs was attained in 43 patients (93%). There were no perioperative deaths. Excluding the 3 most recent cases, the length of follow-up ranged from 56 to 365 months. The majority of patients demonstrated good functional recovery, but regress of the preexisting oculomotor nerve deficit was usually incomplete. No new hemorrhagic events were noted after total resection of BSCMs. In 42 patients (91%), the mRS score at the time of last follow-up was ≤ 2 (favorable outcome), and in 18 (39%), it was 0 (absence of neurological symptoms). Forty-four patients (96%) demonstrated clinical improvement and 2 (4%) had no changes compared with the preoperative period. Multivariate analysis revealed that only lower Lawton grade had a statistically significant independent association (p = 0.0280) with favorable long-term outcome. The area under the receiver operating characteristic curve for prediction of favorable outcome with 7 available Lawton grades of BSCM was 0.93.

CONCLUSIONS

Resection of hemorrhagic BSCMs by an experienced neurosurgeon may be performed safely and effectively, even in severely disabled patients. In the authors' experience, preexisting oculomotor nerve palsy represents the main cause of permanent postoperative neurological morbidity. The Lawton grading system effectively predicts long-term outcome after surgery.

Isolated tectal cavernomas: A comprehensive literature review with a case presentation

Intracranial cavernous angiomas or cavernomas (ICCs) are abnormal blood-filled vasculatures made of mono-endothelial layer and characterized by their bubble-like caverns. Brainstem cavernomas (BSCs) is a critical form of ICCs since slight changes in the lesion can result in devastating or life-threatening outcomes. We hereby present a rare case of BSC developed in the mesencephalic tectum with intraventricular bleeding and Parinaud’s Syndrome. Our patient was managed by complete surgical resection of the lesion through an infra-tentorial supracerebellar approach. Additionally, we reviewed and analyzed the hitherto reported cases of isolated tectal cavernomas (TCs) in the literature, including our case, to elucidate the main factors associated with the management outcomes of TCs. There have been 25 cases of isolated TC reported until now. Most of the patients were adults between 18–77 y of age, except for two children (7 and 13 y). There was no sex predominance. Symptomatic patients presented with headache 56%, altered level of consciousness 24%, and/or double vision 20%. Most cases (64%) had hemorrhagic lesions at presentation, and 60% of all cases experienced recurrent hemorrhages. Parinaud’s Syndrome was recorded in five cases, including the current one. All cases affected with Parinaud’s were males. Lesion size was a determinant of the outcome as larger lesions were more likely to result in persistent deficits. Surgical resection of the lesion was an effective management modality with ∼79% (15/19) of patients who underwent surgery ended up with complete recovery.

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We reviewed and statistically analyzed all reported cases of isolated tectal cavernoma in PubMed literature.

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Isolated tectal cavernoma is not associated with specific sex or a certain age.

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The most common complication associated with this condition is hemorrhage (64%).

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Parinaud’s Syndrome has been associated with some cases, with its presence being male predominant.

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Lesion size is significantly associated with outcome as larger lesions (>11 mm) are more likely to induce persistent deficit.

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Surgical resection is the ultimate management modality as most surgically treated cases ended with complete recovery (79%).

Natural History of Brainstem Cavernous Malformations: On the Variation in Hemorrhage Rates

BACKGROUND

Hemorrhage rates of conservatively managed brainstem cavernous malformations (BSCMs) vary widely in the literature. We aimed to elucidate the reason for the variation and to add the results of our experience of BSCMs management over the past decade.

METHODS

We performed a review of consecutive patients with BSCMs referred to our department in the period 2006-2018. A hemorrhagic event was defined as a radiographically verified intralesional and extralesional hemorrhage. Both retrospective and prospective hemorrhage rates were calculated based on the patient age in years, counted either from birth or from the time of initial presentation until the last contact (or until surgical resection). In addition, we retrieved and reviewed publications with a clear definition of hemorrhagic event and a detailed description of BSCM hemorrhage rate.

RESULTS

In total, 118 patients with BSCMs were reviewed, and 78 patients (mean age on admission 45.9 years) were included in the final analysis. The retrospective and prospective hemorrhage rates were 1.9% (95% confidence interval 1.6%-2.3%) per year and 11.9% (95% confidence interval 7.5%-17.8%), respectively. The retrospective hemorrhage rate in the literature review ranged from 1.9% to 6.8% per year with a median value of 3.8%, whereas the prospective hemorrhage rate ranged between 4.1% and 21.5%, with a median value of 10.2%.

CONCLUSIONS

The reported hemorrhage rates are calculated in 2 different ways. In our patient cohort, both the retrospective and prospective hemorrhage rates were in accordance with those in the literature. The long-term hemorrhage rate lies between the prospective and retrospective rate.

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.

Retrosigmoid transhorizontal fissure approach to lateral pontine cavernous malformation: comparison to transpetrosal presigmoid retrolabyrinthine approach

OBJECTIVE

The retrosigmoid (RS) approach is a classic route used to access deep-seated brainstem cavernous malformation (CM). The angle of access is limited, so alternatives such as the transpetrosal presigmoid retrolabyrinthine (TPPR) approach have been used to overcome this limitation. Here, the authors evaluated a modification to the RS approach, horizontal fissure dissection by using the RS transhorizontal (RSTH) approach.

METHODS

Relevant clinical parameters were evaluated in 9 patients who underwent resection of lateral pontine CM. Cadaveric dissection was performed to compare the TPPR approach and the RSTH approach.

RESULTS

Five patients underwent the TPPR approach, and 4 underwent the RSTH approach. Dissection of the horizontal fissure allowed for access to the infratrigeminal safe entry zone, with a direct trajectory to the middle cerebellar peduncle similar to that used in TPPR exposure. Operative time was longer in the TPPR group. All patients had a modified Rankin Scale score ≤ 2 at the last follow-up. Cadaveric dissection confirmed increased anteroposterior working angle and middle cerebellar peduncle exposure with the addition of horizontal fissure dissection.

CONCLUSIONS

The RSTH approach leads to a direct lateral path to lateral pontine CM, with similar efficacy and shorter operative time compared with more extensive skull base exposure. The RSTH approach could be considered a valid alternative for resection of selected pontine CM.

Endoscopic endonasal surgery to treat intrinsic brainstem lesions: correlation between anatomy and surgery

OBJECTIVE

The endoscopic endonasal approach (EEA) has been proposed as an alternative in the surgical removal of ventral brainstem lesions. However, the feasibility and limitations of this approach to treat such pathologies are still poorly understood. This study aimed to report our experience in five consecutive cases of intrinsic brainstem lesions that were managed via an EEA, as well as the specific anatomy of each case.

METHODS

All patients were treated in a single center by a multidisciplinary surgical team between 2015 and 2019. Before surgery, a dedicated anatomical analysis of the brainstem safe entry zone was performed, and proper surgical planning was carried out. Neurophysiological monitoring was used in all cases. Anatomical dissections were performed in three human cadaveric heads using 0° and 30° endoscopes, and specific 3D reconstructions were executed using Amira 3D software.

RESULTS

All lesions were located at the level of the ventral brainstem. Specifically, one mesencephalic cavernoma, two pontine ca- vernomas, one pontine gliomas, and one medullary diffuse midline glioma were reported. Cerebrospinal fluid leak was the major complication that occurred in one case (medullary diffuse midline glioma). From an anatomical standpoint, three main safe entry zones were used, namely the anterior mesencephalic zone (AMZ), the peritrigeminal zone (PTZ, used in two cases), and the olivar zone (OZ). Reviewing the literature, 17 cases of various brainstem lesions treated using an EEA were found.

CONCLUSIONS

To our knowledge, this was the first preliminary clinical series of intrinsic brainstem lesions treated via an EEA presented in the literature. The EEA can be considered a valid surgical alternative to traditional transcranial approaches to treat selected intra-axial brainstem lesions located at the level of the ventral brainstem. To achieve good results, surgery must involve comprehensive anatomical knowledge, meticulous preoperative surgical planning, and intraoperative neurophysiological moni- toring.