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22 Intervertebral Disc Fenestration

Brigitte A. Brisson

Introduction that the window remains open to offer an alternate path for future
Intervertebral disc (IVD) fenestration involves the mechanical disc extrusion since fibrocartilage fills the void created by fenestra-
removal of the nucleus pulposus (NP) through a window, or fenes- tion soon after surgery [3,5]. Rather, the effectiveness of fenestra-
tration, created in the annulus fibrosus (AF). Fenestration can be tion is thought to be governed by the amount of NP removed at the
performed using an air drill and burr, known as power‐assisted fen- time of surgery [3] and is directly related to the skill and experience
estration, or with a scalpel blade, known as blade fenestration of the operator [6]. Despite skill, complete removal of the remaining
(Figure 22.1) [1,2]. The simple creation of a window within the lat- NP is not expected when performing fenestration [2]. This is sup-
eral AF does not result in a path for any remaining disc material to ported by a recent study that found some residual disc material in
herniate, nor does postoperative chiropractic bending maneuvers all fenestrated discs even after power‐assisted fenestration through
result in disc material being expelled through the fenestration site a lateral approach [7]. A previous cadaver study comparing blade
[1–4]. Studies assessing the fate of the NP following surgical disc and power‐assisted fenestration documented that power‐assisted
fenestration have failed to document a significant inflammatory fenestration removed on average 65% of the NP compared with
reaction which would verify that the remaining disc material is sub- approximately 41% of the NP being removed with blade fenestra-
sequently dissolved preventing recurrence, nor has it confirmed tion [2]. However, the author believes that either technique can

A B

Figure 22.1 Illustration of a transverse section through a canine lumbar intervertebral disc (A) and sagittal view (B) depicting blade fenestration performed
through a lateral approach.

Current Techniques in Canine and Feline Neurosurgery, First Edition. Edited by Andy Shores and Brigitte A. Brisson.
© 2017 John Wiley & Sons, Inc. Published 2017 by John Wiley & Sons, Inc.
Companion website: www.wiley.com/go/shores/neurosurgery

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