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188 Section III: Spinal Procedures

correct site/side was approached, the surgeon might consider Scoliosis and lateral abdominal wall weakness are reported
extending the mini‐hemilaminectomy cranially (most common), complications following fenestration by the dorsolateral muscle
or caudally to find disc that extruded further within the spinal separating technique [31] and have also been reported in dogs
canal. High‐impact, low‐volume disc extrusion or an incorrect undergoing lateral decompression techniques with fenestration [7].
diagnosis should also be considered when significant amounts of It is assumed that these are caused by trauma to the lateral and
disc material are not recovered. In such cases, imaging should be medial branches of the thoracic and lumbar ventral spinal nerves
reviewed and possibly repeated. and are related to the fenestration but this cannot be confirmed [7].
If desired, fenestration of the affected and adjacent disc spaces The muscle weakness typically resolves within a few weeks [7].
can be performed through these approaches (see Chapter 22 and Transection of the nerve root (dorsal, or both dorsal and ventral)
see Video 22.1). would result in some deficits that would be more evident if they
Although Braund et al. [5] described placing gelatin sponge occurred caudal to L3.
over the decompression site prior to closure to prevent dural Late recurrent disc herniation is possible at a previously unaf-
adhesions in the first description of this procedure, fat graft or fected disc space or at the site of surgery if residual disc material
gelatin sponge are not used to cover the surgical site after mini‐ contained within the annulus herniates into the spinal canal post-
hemilaminectomy [7,16]. operatively [11,12,28,32–35]. Fenestration of the surgical site with
or without fenestration of adjacent disc spaces is believed to reduce
Procedure Variations the rate of recurrence [11,12,35].
Partial pediculectomy (Figure 21.1C) has been described as a less
invasive and faster surgical procedure [13]. This procedure requires
adequate knowledge of the lesion location such that the bony Postoperative Care
window is created specifically over the site of lesion and to allow Following pediculectomy, dogs are hospitalized on intravenous
adequate decompression by removal of the extruded disc material. fluids and injectable analgesics until sufficiently comfortable to
For these reasons, partial pediculectomy is not recommended as the receive oral medications (typically 24 hours). Discharge is most
standard decompression technique. commonly within 48 hours of surgery in patients that retain motor
function. Dogs with loss of motor function are typically discharged
Closure (Video 21.8)
Standard closure of the deep and superficial thoracolumbar fascia is once voluntary urinary control is confirmed or when the owner is
performed using a simple continuous pattern of absorbable mono- comfortable expressing the bladder at home. Postoperative rehabili-
filament suture. When approaching more than one site using the tation is recommended in most cases (see Chapter 29). For general
modified dorsolateral approach, the longissimus muscle incision is postoperative recommendations, see Chapter 28.
also closed using a simple continuous pattern. The subcutaneous As for hemilaminectomy, overall, recovery rates of greater than
tissues and skin are closed routinely. 90% have been reported following mini‐hemilaminectomy with or
without prophylactic fenestration [6–12].

Complications
The presence of residual disc material is noted in as many as 100% Video clips to accompany this book can be found on
of patients that recover satisfactorily after hemilaminectomy but is the companion website at:
rarely found to be clinically significant [26]. In contrast, residual www.wiley.com/go/shores/neurosurgery
disc material (7.7%, range 0–27.3%) was found in 44% of nine
patients undergoing mini‐hemilaminectomy when preoperative
and postoperative MRI were compared [16]. Delayed recovery or
lack of postoperative improvement has been associated with the References
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vantage of mini‐hemilaminectomy is that the lateral or oblique 1978. J Am Anim Hosp Assoc 1978;14:563–570.
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prefer approaching the left side [30]. An advantage of the pediculec- thoracolumbar disc protrusion. J Small Anim Pract 1994;35:351–356.
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hemilaminectomy”. J Small Anim Pract 1988;29:611–616.
without compromise to the bony support or soft tissues [30]. 10 Lubbe AM, Kirberger RM, Verstraete FJM. Pediculectomy for thoracolumbar spi-
Hemorrhage is typically minor and in most instances is easily nal decompression in the dachshund. J Am Anim Hosp Assoc 1994;30:233–238.
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