Determination of surgical exposure obtained with integrated endoscopic thoracolumbar hemilaminectomy in large‐breed cadaveric dogs

Abstract

Objective: To define boundaries of minimally invasive integrated endoscopic hemilaminectomy at 4 sites in the canine thoracolumbar spine. Study design: Experimental, randomized cadaveric study. Animals: Six cadaver dogs that had been humanely euthanized for reasons unrelated to this study. Methods: Hemilaminectomy was performed with an integrated endoscopic system at T11-12, T12-13, L1-2, and L2-3, 1 at each site, on the left or right side of each dog. Each site was randomly assigned either a 19-mm or a 23-mm cannula. The entire procedure, including soft tissue dissection, was performed through the cannula. Afterward, spines were imaged by computed tomography (CT) to measure the cranial and caudal extent of the hemilaminectomy from the center of the disc space. Results: The mean AE SD cranial extent of the hemilaminectomy was 4.5 ± 1.4 mm for the 19-mm cannula and 5.6 ± 1.4 mm for the 23-mm cannulas (P = .0757). The caudal extent of the hemilaminectomy was 9.5 ± 2.2 mm for the 19-mm cannula and 10.3 ± 1.6 mm for the 23-mm cannula (P = .206). The mean length of the hemilaminectomy was 13.0 ± 1.5 mm for the 19-mm cannula and 15.0 ± 2.1 mm for the 23-mm cannula (P = .022). Conclusion: Integrated endoscopic systems were reliably used to access the spinal canal within the range of the above measurements relative to the disc space as identified by CT or magnetic resonance imaging. Clinical significance: Integrated endoscopy can be considered as an option in dogs with thoracolumbar disc extrusions or other pathology measuring within the parameters defined by this study. Access may be possible beyond the dimensions defined in this study with probing and repositioning.

Minimally invasive microsurgical decompression of an intervertebral disc protrusion in a dog

“…We concluded that the minimally invasive intramuscular approach through a 2‐cm channel offered adequate access to the target area, with the tendinous attachment onto the articular process as the sole structure being cut. These findings support the reports of MISS cadaveric study on the feasibility of the techniques.…”

“…Surgical loupes are popular among neurosurgeons but offer only limited magnification. The use of exoscopes and endoscopes has been reported in a few veterinary reports . Video‐assisted ventral slots have been used in cadavers and in clinically affected dogs, whereas mostly cadaveric studies have been reported for the thoracolumbar and lumbosacral region, with only one report of using an endoscope in a study in live dogs .…”

“…Benefits associated with MISS strategy include smaller incision, less soft‐tissue damage, less blood loss, lower complication rate, less scarring, less postoperative pain, quicker recovery, shorter hospital stay, and a quicker return to daily life activity . Although MISS is common practice in human neurosurgery, limited reports have been published on its use for the thoracolumbar spine in dogs . All these reports except one (percutaneous endoscopic pediculectomy) refer to canine cadavers.…”

Microendoscopic Mini-Hemilaminectomy and Discectomy in Acute Thoracolumbar Disc Extrusion Dogs: A Pilot Study

“…In veterinary literature, most studies have evaluated a minimally invasive approach to the spine in canine cadavers or clinically normal dogs. For the thoracolumbar spine, endoscope-assisted [ 12 , 13 ] and full-endoscopic procedures have been reported [ 14 , 15 , 16 ]. A minimally invasive device with video assistance was used in studies with canine cadavers and in 10 clinical cases that underwent ventral slot decompression [ 17 ].…”

Minimally invasive spine surgery in dogs: Evaluation of the safety and feasibility of a thoracolumbar approach to the spinal cord

“…Standard approaches to the spine, so called open techniques , involve muscle dissection from the bony elements with removal of ligaments, tendons, and bony structures, which are all important parts of the dorsal stabilizing element of the spine . Because of the frequency of spinal surgery in dogs, interest in MISS has been growing . However, most studies are limited to dog cadavers; only two reports have described MISS thoracolumbar technique in live dogs .…”