Effect of intraoperative positioning on the diameter of the vertebral canal in cats during perineal urethrostomy (cadaveric study)

Abstract

Objectives The objective of this study was to quantify the changes in the diameter of the vertebral canal in the lumbosacral and sacrococcygeal column (L6-Co2) in cats in dorsal and ventral recumbency, simulating real body positioning during a perineal urethrostomy. Methods Twenty-one male feline cadavers were enrolled in the study. All feline cadavers were evaluated by CT. Examinations were performed with the cadaver in a neutral position and dorsal and ventral recumbency. Sagittal vertebral canal diameters (VCDs) were obtained by measuring the distance between the ventral and dorsal aspects of the vertebral canal in the middle of the intervertebral space. Results A comparison of the VCDs between L6 and L7, L7 and S1, S3 and Co1 and Co1 and Co2 in neutral position vs dorsal recumbency revealed a reduction of 0.27 mm (14.6%; P <0.001) between S3 and Co1 and 0.26 mm (18.1%; P <0.001) between Co1 and Co2. No differences were seen when comparing L6-L7 and L7-S1. The VCDs were decreased in all segments when comparing neutral with ventral recumbency. This study revealed a reduction of 0.13 mm between L6 and L7 (3.3%; P = 0.003), 0.14 mm between L7 and S1 (4.1%; P = 0.003), 0.61 mm between S3 and Co1 (32.5%; P <0.001) and 0.63 mm between Co1 and Co2 (44.1%; P <0.001). Comparison of the VCD between dorsal and ventral recumbency in L6-L7, L7-S1, S3-Co1 and Co1-Co2 revealed a decrease in the VCDs in ventral recumbency of 0.13 mm (3.3%; P <0.001), 0.12 mm (3.6%; P <0.001), 0.34 mm (21.0%; P <0.001) and 0.37 mm (31.7%; P <0.001), respectively. Conclusions and relevance The results provide evidence that, from an anatomical point of view, perineal urethrostomy performed in dorsal recumbency is superior to ventral recumbency, but further clinical studies to verify these findings are necessary.

Evaluation of postoperative complication rates in cats undergoing perineal urethrostomy performed in dorsal recumbency

“…Slunsky et al reported a significant decrease in diameter of the vertebral canal in patients placed in ventral recumbency with tail hyperextended and pulled cranially. 23 The hyperextension required to keep the tail out of the surgical field when cats are placed in ventral recumbency can lead to damage to the lumbosacral and sacral plexus, causing clinical signs similar to a tail pull injury, which has been shown to cause urinary tract dysfunction. 23 Slunsky et al concluded that performing PU in dorsal recumbency is superior to ventral recumbency.…”

“…23 The hyperextension required to keep the tail out of the surgical field when cats are placed in ventral recumbency can lead to damage to the lumbosacral and sacral plexus, causing clinical signs similar to a tail pull injury, which has been shown to cause urinary tract dysfunction. 23 Slunsky et al concluded that performing PU in dorsal recumbency is superior to ventral recumbency. 23 This retrospective evaluation of cats having a PU in dorsal recumbency reports minimal short-and longterm minor complications and no major complications.…”

“…23 Slunsky et al concluded that performing PU in dorsal recumbency is superior to ventral recumbency. 23 This retrospective evaluation of cats having a PU in dorsal recumbency reports minimal short-and longterm minor complications and no major complications. Of the clients who responded to our questionnaire, all were satisfied with their pet's outcome and reported good-to-excellent quality of life for their cat, which is similar to previous findings of 94% owner satisfaction and 88-89% good quality of life.…”

Effect of intraoperative positioning on postoperative neurological status in cats after perineal urethrostomy

“…Perioperative positioning of cats in dorsal or ventral recumbency was performed as described by Slunsky et al 9 For dorsal recumbency the thoracic limbs were tied in a caudal direction and the pelvic limbs in a cranial direction using gauze. The tail hung free over the surgical table (Figure 1).…”

“…According to the authors, the reduction in the diameter of the vertebral canal between the sixth lumbar and second coccygeal vertebrae may directly or indirectly lead to positioning-dependent iatrogenic nerve injury. 9…”