Use of bilateral superficial gluteal muscle flaps for the repair of ventral perineal hernia in dogs: A cadaveric study and short case series.

OBJECTIVE: To describe bilateral mobilization of the superficial gluteal muscle (SGM) to treat ventral perineal hernias in dogs. STUDY DESIGN: Cadaveric study and short case series. SAMPLE POPULATION: Male dog cadavers (n = 10) weighing between 5 and 42 kg and three dogs treated for ventral perineal hernia. METHODS: Cadavers were positioned in right and left lateral recumbency to free the origin and insertion of the ipsilateral SGM except for muscle fibers originating on the first tail vertebra and sacrotuberous ligament. The dogs were placed in ventral recumbency to approach the perineum and rotate the muscle flaps. The insertions of the SGM were sutured together ventral to the anal sphincter muscle. The dorsal border of the overlapping tendons was sutured to the anal sphincter muscle, and the ventral border was sutured to the ischiourethralis muscle. The amount of overlap between bilateral flaps was measured. The SGM flaps were used to revise recurrent perineal hernias in three dogs. RESULTS: Superficial gluteal muscle flaps were created without damage to the blood supply in all dogs. The overlap between the bilateral flaps ventral to the anal sphincter measured 0 to 2.4 cm. No recurrence was detected at follow-up (6-12 months) in the three dogs treated with these flaps. CONCLUSION: Superficial gluteal muscle flaps were mobilized without damage to the blood supply and crossed the midline ventral to the anal sphincter. Flaps were used successfully to repair ventral perineal hernias in three dogs. CLINICAL SIGNIFICANCE: Bilateral SGM flaps can be considered to repair ventral perineal hernias.

Pin Size Selection for Normograde Intramedullary Pinning of Distal Humeral Fractures in the Dog.

OBJECTIVE: To determine the optimal intramedullary (IM) pin size for open and percutaneous normograde pinning of the distal humerus. STUDY DESIGN: Ex vivo anatomic study. SAMPLE POPULATION: Sixteen canine cadavers. METHODS: Sixteen pairs of forelimbs were harvested from canine cadavers weighing 25-35 kg. The craniocaudal diameter of the humeral medullary canal, at the distal 80th percentile of its length, was measured on a lateral radiograph. Forelimbs within each pair were allocated to percutaneous or open pinning techniques. Cadavers were divided into three groups based on IM pin diameter relative to the medullary canal diameter: Group 25-35%, Group 36-45%, and Group 46-55%. Pins were inserted normograde into the medial epicondyle and advanced until they exited the proximal humerus. Pin tracts were dissected and damage to soft tissue, bony structures, and location of entry and exit points were documented. The humeri were also cut at the thinnest point of the medial epicondyle and damage to the bone was evaluated. RESULTS: There was no difference in any of the outcomes between the open and percutaneous techniques. Cortical damage was more frequent in Group 46-55% and included blanching and or fracture of the cortex of the medial epicondyle, with fracture occurring in 6/10 limbs in this group. Pins in Group 46-55% exited the farthest and most distal from the optimal exit point and were difficult to place in all limbs. CONCLUSION: This study supports a recommendation for open and percutaneous pinning of the humerus with IM pins 36-45% of the medullary canal diameter measured at the distal 80th percentile of humeral length.

The effect of extension and loading of the carpus on radial rotation.

OBJECTIVE: To describe the direction and magnitude of the rotation of the radius relative to the ulna during extension of the carpus and to describe the effect of carpal extension on internal and external rotation of the radius relative to the ulna. STUDY DESIGN: In vitro experiment. ANIMALS: Cadaveric canine thoracic limbs (n = 11). METHODS: Eleven thoracic limbs were collected from 6 healthy mixed breed dogs of medium build. Each specimen was radiographed to ensure that the carpal and elbow joints were free of pathology. The elbow joint was disarticulated and the distal thoracic limb was prepared for biomechanical testing. Each specimen was stripped of soft tissue, leaving the soft tissues around the proximal aspect of the radius and ulna intact. The interosseous ligament, pronator teres muscle, and all the soft tissues distal to the distal metaphysis of the radius were also left intact. In the 1st part of the study, the rotation of the radius relative to the ulna was measured while extending the carpal joint using a system of weights and pulleys attached to the manus. In the 2nd part of the study, the internal and external rotation of the radius relative to the ulna was performed by applying an internal and external rotational load to the radius using a system of weights and pulleys attached to the radius. The internal and external rotation of the radius was measured with the carpus unloaded and with the carpus extended by applying a load of 5 kg to the manus. RESULTS: Extension of the carpus resulted in internal rotation of the radius relative to the ulna. With the carpus extended under a maximum load of 2 kg, the mean (± SD) internal rotation of the radius was 4.3 ± 2.1° for all specimens. With the carpus unloaded, the mean internal and external rotation of the radius was 11.5 ± 2.9° and 22.5 ± 7.7° for all specimens, respectively. With the carpus loaded (extended under 5 kg load), the mean internal and external rotation of the radius was 3.3 ± 1.2° and 7.3 ± 2.0° for all specimens, respectively. The difference between internal and external rotation with the carpus loaded and unloaded was significant. CONCLUSION: Extending the carpus results in internal rotation, and proximal translation of the radius relative to the ulna. Loading the carpus in extension decreases the internal and external rotation of the radius relative to the ulna. A better understanding of the interaction between the carpus and the elbow may improve our understanding of the pathogenesis of elbow dysplasia.

Transient megaoesophagus and oesophagitis following diaphragmatic rupture repair in a cat.

A 6-month-old domestic shorthair female cat was presented with suspected diaphragmatic hernia (DH) that was later confirmed by thoracic radiography. The cat underwent exploratory celiotomy with a diaphragmatic rupture (DR) repair and recovered. Six days later, it was represented with vomiting and anorexia. Megaoesophagus (MO) and gastric dilatation were diagnosed by contrast radiography. A second celiotomy revealed no abnormalities and gastropexy was performed. Endoscopy demonstrated MO, oesophagitis and gastro-oesophageal reflux. MO persisted for several weeks and was an unexpected complication as no association between DR (or DH) and MO has never been described in the veterinary literature. The cat was treated medically with aggressive prokinetic and antacid therapy along with prolonged temporary oesophageal diversion (percutaneous endoscopic gastrostomy tube) with an excellent outcome.

In vitro study of the ilial anatomic landmarks for safe implant insertion in the first sacral vertebra of the intact canine sacroiliac joint.

OBJECTIVE: To define landmarks on the canine ilial wing for accurate, consistent insertion of implants into the 1st sacral (S1) vertebral body when the sacroiliac joint is intact. STUDY DESIGN: Anatomic study. ANIMALS: Intact, cadaveric canine pelves and sacra (n=25). METHODS: Median sections (5 specimens) were drilled from the center of S1 in a lateral direction, exiting on the ilial wing. Landmarks on the ilial wing and shaft used to define this exit point were then used to locate this point on both wings of 20 articulated specimens, positioned and rigidly held so that the dorsal plane of the pelvis was aligned with a plumb line and the median plane of the pelvis was horizontal. A 2 mm hole was drilled from the marked point, parallel to the plumb line, until it exited the contralateral ilial wing. Distance of drill hole position from the geometric center (GC) of S1 was located on median and paramedian plane images derived from plane, computed tomographic (CT) scans. RESULTS: The entire drill hole was located within S1 in 18 specimens. Mean deviation of the hole from GC (ratio of the distance of GC from the closest S1 body border) in median section was 0.40 +/- 0.29 (craniocaudal direction) and 0.29 +/- 0.23 (dorsoventral). CONCLUSIONS: Use of ilial wing landmarks and drilling perpendicular to the median plane will improve accuracy for insertion of implants into S1 when the sacroiliac joint is intact. CLINICAL RELEVANCE: Ilial wing landmarks should be used to improve accuracy of implant insertion into S1.