Elsevier

World Neurosurgery

Volume 84, Issue 6, December 2015, Pages 2043-2052
World Neurosurgery

Technical Note
Venous-Preserving Sylvian Dissection

https://doi.org/10.1016/j.wneu.2015.07.050Get rights and content

Objective

The Sylvian fissure has been dissected through the frontal side of the superficial Sylvian veins with sacrifice of the tributaries of the frontal superficial Sylvian vein, which may lead to venous infarction. In addition, disturbed venous drainage makes the brain susceptible to brain retraction. Therefore, preservation of the vein is essential in modern neurosurgery to decrease morbidity.

Methods

We describe the technical nuances of Sylvian dissection with an emphasis on preserving the veins.

Results

The arachnoid between the frontal and temporal superficial Sylvian veins is divided as to enter the fissure. After the deep part in the Sylvian fissure is reached, the inside of the fissure is dissected along the “microvascular Sylvian fissure,” the temporal side of the frontal vessels or the frontal side of the temporal vessels. The Sylvian fissure is dissected in a deep-to-superficial and posterior-to-anterior fashion (“paperknife technique”) up to the skull base. The frontal superficial Sylvian vein usually tethers the brain to the dura, restricting the surgical corridor when approaching deep lesions. Peeling off the arachnoid that wraps this vein (“denude technique”) allows the vein to stretch.

Conclusions

Keeping the proper dissection plane (“microvascular Sylvian fissure”) is crucial to preserve the veins. The “paperknife technique” makes the division of the frontal and temporal lobe easier. The “denude technique” provides a wider space between the frontal lobe and the skull base. These techniques make it possible to obtain a sufficiently wide surgical corridor to the basal cistern without sacrificing the veins and their tributaries.

Introduction

The Sylvian fissure lies between the frontal and temporal lobes from lateral to medial, making it possible to approach the deep lesions through this fissure. Sylvian dissection is one of the requisite skills for microneurosurgeons, because the Transsylvian approach, combined with frontotemporal craniotomy and its modifications, is one of the most versatile and commonly performed approaches 3, 6, 7, 13, 19.

The superficial Sylvian veins, one of the three dominant venous drainage systems of the lateral cerebrum, lie on the surface of the Sylvian fissure. They usually drain into the dural sinus along the sphenoid wing. In other words, they bridge the brain and the dura, which can obstruct the surgeon’s perspective or prevent the brain from retracting. Therefore, the superficial Sylvian veins, especially the frontal superficial Sylvian veins, are occasionally sacrificed during dissection 13, 15, 19. Venous infarction or severe cerebral edema caused by venous congestion may follow, resulting in neurologic deficits 11, 15, 17.

Considering it is difficult or impossible to foresee the consequence of sacrificing the veins, the surgeon should endeavor to save the superficial Sylvian veins while reserving a wide enough space within the surgical field for safe manipulation. Few techniques to preserve these veins, however, have been described 5, 12, 18. We think that identification of the correct dissecting plane is of great importance. Several tips and tenets described here are useful to save the veins.

Section snippets

Materials and Methods

We describe technical nuances for dissection of the Sylvian fissure with an emphasis on preserving the superficial Sylvian veins. We usually split the lateral Sylvian fissure widely in a distal (lateral-to-medial) fashion, even for deep lesions around the basal cisterns, but we believe that at least a part of this technique can be applied to the proximal (medial-to-lateral) transsylvian approach or an approach with a small Sylvian opening (3).

Between April 2011 and March 2015, we operated on 66

Craniotomy

The patient is placed in the supine position with the head rotated and the neck extended according to the location of the lesion. A typical frontotemporal craniotomy is made, and the greater wing of the sphenoid bone is removed. The dura is opened by a semicircular incision, revealing the Sylvian fissure and the frontal and temporal lobe. Then, we introduce an operative microscope for Sylvian dissection.

Opening the Surface of the Sylvian Fissure between the Superficial Sylvian Veins

The superficial Sylvian veins vary in size and number among patients and between the 2 sides

Discussion

This report described technical nuances of venous-preserving Sylvian dissection, which is different from the conventional Sylvian split with sacrificing of the frontal veins. Accurate recognition of the anatomy of the superficial veins and “microvascular Sylvian fissure” helps the surgeon find the best dissection plane. This plane may be between the frontal vessels and the temporal vessels, between the frontal lobe and the temporal vessels, or between the temporal lobe and the frontal vessels.

Conclusion

Preserving the veins is of great importance in modern neurosurgery to decrease postoperative morbidity. The traditional Sylvian split that mechanically sacrifices the frontal superficial Sylvian veins and its tributaries should be reconsidered. With the use of the technique described in the present report, the Sylvian fissure is divided safely, and a wide surgical corridor is achieved.

References (19)

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Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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