Presigmoid Approach for Cavernous Angioma in the Pons. Technical Note.

Abstract

Surgical treatment of brainstem lesions has been encouraged after the development of magnetic resonance imaging. However, direct approaches to intra-axial lesions in the brainstem still carry a high risk of morbidity because the neuronal structures can be injured along the entry routes. We present two patients whose pontine cavernous angiomas were removed via incision of the lateral aspect of the pons with presigmoid approach. The first case, a 41-year-old woman, presented with paresis of the cranial nerves VI, VII, and VIII, and left hemiparesis progressing over 2 weeks caused by a cavernous angioma ventrally located in the lower pons. The second case, a 50-year-old woman, developed dizziness over 2 months due to a large cavernous angioma in the center of the pons. These lesions were totally removed through the presigmoid approach and no additional neurological deficits were observed. An imageguided navigation system was used for the craniotomy and removal of the lesion in the second patient. The presigmoid approach provides a safe route to intra-axial lesions in the pons. A technique for presigmoid craniotomy with one-piece bone flap under the image-guided navigation is also described.

Gradual Deterioration of Brainstem Cavernous Angioma Associated With Hemophilia -Case Report-

“…7,9) Surgical removal must preserve the venous anomalies associated with the lesion, as well as the detailed anatomy of the neural nucleus and neural tracts. 9) In our present case, the hematoma was partially exposed on the surface of the floor of the fourth ventricle, so we could approach the hematoma cavity from this entry to safely remove the lesion.…”

Direct Approach to the Ventrolateral Medulla for Cavernous Malformation. Case Report.

“…The surgical approach depends on the location of the cavernous malformation in the brainstem, and the technical considerations for surgical intervention to treat intrinsic lesions of the ventral medulla. [1][2][3]11,20) Surgery has been considered risky due to the possibility of injuring vital structures or damaging the perforating arteries coursing from the ventrolateral aspect of the medulla. Safe entry zones might be identified, even on the anterior surface of the medulla, through an anterolateral sulcus at the level between the radicles of the hypoglossal nerve and the C-1.…”

“…5,7,[13][14][15][16]21) Neurological deficits are likely to worsen due to repeated hemorrhages, so the current trend is toward aggressive management of lesions reaching the pial or ependymal surface of the brainstem, but extreme care is required perioperatively since vital structures in life-support functions are located at the brainstem. 2,5,9,[11][12][13][14]16,21) Direct resection through various approaches has been used for cavernous malformations located primarily in the midbrain and pons since there is only minor risk of inflicting further neurological damage. 4,6,8,[10][11][12][17][18][19] The indications for surgical treatment and selection of the most appropriate surgical routes may be indeterminable for cavernous malformations with neither bulging nor extension into the pial or ependymal surface.…”

“…2,5,9,[11][12][13][14]16,21) Direct resection through various approaches has been used for cavernous malformations located primarily in the midbrain and pons since there is only minor risk of inflicting further neurological damage. 4,6,8,[10][11][12][17][18][19] The indications for surgical treatment and selection of the most appropriate surgical routes may be indeterminable for cavernous malformations with neither bulging nor extension into the pial or ependymal surface.…”

The lateral infratrigeminal transpontine window to deep pontine lesions

“…4,20,34 More recently, the need to further reduce the impact of surgical sequelae affecting a patient's quality of life and the refinement of neurophysiological monitoring has pushed some groups to explore and develop lateral alternative approaches to the deep pons. 10,15,17,25 Given these historical considerations, this study focused attention on the technical aspects and results of surgery for deep pontine lesions when approached through the lateral infratrigeminal window.…”