The sub-pial resection technique for intrinsic tumor surgery

Abstract

Background: The technique of sub-pial resection, first described in the early 1900s, was later refined by Penfield and Jasper for removal of supratentorial epileptic cortex. This technique has not been widely adopted for intrinsic tumor resection, for which the most widely used technique involves piecemeal aspiration of the tumor. This technique of "staying within the tumor" results in persistent bleeding, with obscuration of the tumor/brain interface, potentially yielding less than satisfactory results. In our experience, the sub-pial technique is useful for resections of supratentorial intrinsic tumor. We report the use of sub-pial resection technique and present illustrative cases.

Methods: The sub-pial resection technique is described along with important clinical decision-making guidelines. Representative cases are presented to discuss application of the sub-pial technique and to demonstrate surgical results.

Results: The sub-pial technique preserves the pia during cortical resections and makes it easier to protect and identify normal anatomy, including sulci, gyri, cranial nerves, and major vascular structures. This reduces bleeding, making surgery safer and more efficient. In most cases, an en bloc resection can be accomplished, permitting more accurate histopathology and more extensive tissue acquisition for research purposes.

Conclusion: The sub-pial technique can be incorporated into strategies for supratentorial intrinsic tumor resections, including temporal, frontal, occipital, and insular tumors, at para-Sylvian or para-insular-sulcus locations.

Keywords: En bloc resection; astrocytoma; neurosurgical procedures; sub-pial resection; supratentorial intrinsic tumor.

Figure 1

Illustration of sub-pial resection along anterior temporal operculum, protecting the vessels in the Sylvian fissure (see also Video 1) on the opposite side of the pia. Feeding vessels of the tumor were easily devascularized as they emanated through the pia during en blocresection

Figure 2

A 28-year-old right-handed female with residual left frontal lesion. Repeat craniotomy for resection. (a) Axial T2 MRI prior to original surgery at an outside hospital, showing abnormal hyperintensity in the left frontal area. (b) Axial T2 MRI prior to repeat craniotomy showing residual abnormal T2 signal. (c) Axial T2 MRI, after resection using sub-pial technique, showing the medial, lateral and posterior pial borders of the en blocresection, with trace residual abnormal T2 signal along the pars triangularis laterally. (d) Coronal T1 with contrast after repeat surgery, showing the inferior, medial and lateral pial borders of the resection

Figure 3

A 56-year-old right-handed male with 2-year history of progressive difficulties with short-term memory. (a) Axial T1 with contrast preoperatively showing a temporal parietal cystic enhancing lesion abutting the pulvinar and extending into the atrium. (b) Sagittal T1 with contrast preoperatively showing the lesion. (c) Coronal T1 with contrast postoperatively showing the medial, lateral and inferior pial borders of the resection. (d) Axial T1 with contrast postoperatively showing the pial borders of the resection with removal of the hippocampus and the uncus

Figure 4

A 66-year-old right-handed female with right temporal occipital enhancing lesion. (a) Axial T1 with contrast preoperatively. (b) Axial T1 without contrast postoperatively showing trace hyperintensity signal along the resection bed, from blood products. (c and d) Axial and sagittal T1 with contrast postoperatively, respectively, showing the resection cavity after en bloc resection of the tumor

Figure 5

A 48-year-old right-handed male with progressive left anterior insular tumor. (a) Coronal T1 with contrast MRI preoperatively showing the non-enhancing hypointense lesion. (b) Sagittal T1 without contrast MRI preoperatively; closed arrow head denotes tumor anterior to the anterior circular sulcus; asterisk denotes anterior circular sulcus; open arrow head denotes tumor within the first two short insular gyri. (c) Coronal T1 with contrast MRI postoperatively; arrow head denotes the resection cavity showing the superior, medial and inferior pial borders of the resection. (d) Sagittal T1 with contrast MRI postoperatively, arrow heads denote the pial borders of the resection. Sylvian fissure was not opened during the operation