Surgical Approaches to the Temporal Horn: An Anatomic Analysis of White Matter Tract Interruption

Operative Neurosurgery 13:258–270, 2017

Surgical access to the temporal horn is necessary to treat tumors and vascular lesions, but is used mainly in patients with mediobasal temporal epilepsy. The surgical approaches to this cavity fall into 3 primary categories: lateral, inferior, and transsylvian. The current neurosurgical literature has underestimated the interruption of involved fiber bundles and the correlated clinical manifestations.

OBJECTIVE: To delineate the interruption of fiber bundles during the different approaches to the temporal horn.

METHODS:We simulated the lateral (trans-middle temporal gyrus), inferior (transparahippocampal gyrus), and transsylvian approaches in 20 previously frozen, formalin-fixed human brains (40 hemispheres). Fiber dissection was then done along the lateral and inferior aspects under the operating microscope. Each stage of dissection and its respective fiber tract interruption were defined.

RESULTS: The lateral (trans-middle temporal gyrus) approach interrupted “U” fibers, the superior longitudinal fasciculus (inferior arm), occipitofrontal fasciculus (ventral segment), uncinate fasciculus (dorsolateral segment), anterior commissure (posterior segment), temporopontine, inferior thalamic peduncle (posterior fibers), posterior thalamic peduncle (anterior portion), and tapetum fibers. The inferior (transparahippocampal gyrus) approach interrupted “U” fibers, the cingulum (inferior arm), and fimbria, and transected the hippocampal formation. The transsylvian approach interrupted “U”fibers (anterobasal region of the extreme capsule), the uncinate fasciculus (ventromedial segment), and anterior commissure (anterior segment), and transected the anterosuperior aspect of the amygdala.

CONCLUSION: White matter dissection improves our knowledge of the complex anatomy surrounding the temporal horn. Identifying the fiber bundles at risk during each surgical approach adds important information for choosing the appropriate surgical strategy.

 

A surgical technique to expand the operative corridor for supracerebellar infratentorial approaches

Supracerebellar corridor

Acta Neurochir (2013) 155:1895–1900

The supracerebellar infratentorial approach is a commonly used route in neurosurgery. It provides a narrow and deep corridor to the dorsal midbrain and pineal region. The authors describe a surgical technique to expand the operative corridor and the surgeon’s working angles during this approach.

Methods Thirteen cases of patients who underwent resection of their lesions using this extended approach were reviewed. During their suboccipital craniotomy, additional bone over the transverse sinus (paramedian approach) and the confluence of the sinuses (midline approach) were removed. Two sutures (tentorial stay sutures) were anchored to the tentorium anterior to the transverse sinus and tension was applied. A video narrated by the senior author describes the details of technique.

Results This additional bone removal and tentorial stay sutures led to gentle elevation of the tentorium and partial mobilization of the dural venous sinuses superiorly. This technique enhanced operative viewing through improved illumination and expanded working angles for microsurgical instruments while minimizing the need for fixed retractors and extensive cerebellar retraction. All patients underwent satisfactory removal of their lesions. No patient suffered from any related complication.

Conclusion The use of stay sutures anchored on the tentorium is a simple and effective technique that expands the surgical corridor during supracerebellar infratentorial approaches.

Keywords Supracerebellar infratentorial approach . Stay sutures . Retraction . Operative corridor . Surgical procedures . Operative