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21 Pediculectomy/Mini‐Hemilaminectomy

Brigitte A. Brisson

Indications spinal cord manipulation [5,6,15,16]. Direct access to the dorsal
Surgical decompression of thoracolumbar intervertebral disc (IVD) aspect of the canal may be limited compared with hemilaminec-
herniation has traditionally been accomplished by dorsal laminec- tomy, as was demonstrated in a recent study [15], but this was not
tomy [1–3] or hemilaminectomy [4]. Dorsal laminectomy is no shown to have an impact on the ability to retrieve disc material in
longer in favor to treat thoracolumbar IVD herniation since clinical patients [16]. This surgical approach offers good visualiza-
removal of the extruded disc material located ventral to the spinal tion of the dorsal nerve root and ganglia and of the venous sinus
cord is not possible using this approach or requires significant spi- located on the floor of the spinal canal [5,15]. Preservation of the
nal cord manipulation [5]. Lateral and modified lateral decompres- majority of the articular processes reduces postoperative vertebral
sion techniques [5–8], also known as mini‐hemilaminectomy [9], instability compared with the hemilaminectomy procedure [14].
pediculectomy or extended foraminotomy [10–12], along with the Effective spinal cord decompression can be achieved from T10 to
partial pediculectomy procedure [13] have aimed to achieve spinal L6 using this procedure [5]. The dorsolateral and lateral approaches
cord decompression through less invasive approaches that preserve used for pediculectomy also allow direct access to the IVD for fen-
the zygapophyseal joint and remove less vertebral bone [5–7,9,10] estration [5,6,13]. Like the hemilaminectomy procedure, the pedi-
(Figure 21.1). These procedures are reportedly quicker to perform, culectomy window is created close to the vertebral venous plexus
create less tissue trauma and less vertebral instability, and lead to a (sinus) and foraminal structures, requiring care to prevent hemor-
more rapid postoperative recovery [5,9,10,13,14]. Although there rhage and nerve root damage [5,16]. The partial pediculectomy
are discrepancies in the literature, pediculectomy and mini‐hemi- procedure (Figure 21.1C) creates a window that is limited to the
laminectomy are considered by the author as the same procedure pedicle bone of one vertebra and does not invade the intervertebral
and the terms are used interchangeably in this chapter. foramen, thus reducing the risk of hemorrhage from the vertebral
vessels [13]. However, it may provide too small a window to ade-
quately decompress extensive lesions or ensure that all the extruded
Procedure disc material is removed. In fact, one study reported that 8 of 27
Pediculectomy (or mini‐hemilaminectomy) consists of removing a dogs (29%) undergoing partial pediculectomy required extension
portion of the pedicle bone of two adjacent vertebrae to essentially of the partial pediculectomy into a mini‐hemilaminectomy in order
enlarge the intervertebral foramen while preserving the articular to retrieve the extruded disc material located within the interverte-
processes [5–10] (Figure 21.1B) Although the partial pediculec- bral foramen [13]. In addition, blind probing of the vertebral canal
tomy technique described by McCartney [13] spares the accessory is typically performed during partial pediculectomy to ensure that
process (Figure 21.1C), the pediculectomy procedure removes the the extruded disc material has been removed and this can increase
accessory process to form the dorsal margin of the laminectomy the risk of venous sinus hemorrhage [13].
[5,9,10]. As shown in two recent studies [15,16] the removal of A pediculectomy or mini‐hemilaminectomy can easily be con-
the accessory process results in mild to moderate invasion of the verted into a hemilaminectomy (Figure 21.1A) or be extended over
ventral aspect of the articular processes in most dogs. several adjacent vertebrae if required [5]. The author has performed
The window provided by the pediculectomy or mini‐hemilami- continuous pediculectomies over as many as five contiguous verte-
nectomy is adequate for visualizing the ventrolateral aspect of the brae without complication. Because the pediculectomy does not
vertebral canal and provides excellent access for retrieving ventrally significantly invade the articular processes, it can also be performed
or laterally extruded disc material while limiting intraoperative bilaterally without causing vertebral instability. However, this is

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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