Veterinary Surgical Principles Flashcards

During a jejunal resection in a dog, you are assessing anastomosis viability. Which combination of findings most reliably indicates that the anastomotic segment should be extended further into healthy tissue?

Answer: Absence of peristalsis and mucosal pallor at the cut edge under fluorescent lighting with sodium fluorescein

Sodium fluorescein combined with a Wood's lamp (or fluorescent light) is the most objective intraoperative test for bowel viability. Absent fluorescence at the cut edge indicates inadequate perfusion even when gross appearance is ambiguous. Absence of peristalsis alone is unreliable (it can return after handling), but combined with fluorescein non-uptake this indicates non-viable tissue that must be removed. Thin walls with hyperemic serosa and brisk bleeding actually suggest viable, reactive tissue.

A 6-year-old intact male cat undergoes perineal urethrostomy. Two weeks postoperatively the owner reports urine scalding and a narrow urinary stream. Retrograde urethrogram reveals a focal stricture at the anastomotic site. Which suture technique error during the original procedure is MOST likely responsible?

Answer: Excessive tension on interrupted sutures placed too close to the urethral mucosa edge, causing ischemic necrosis

Stricture formation at a perineal urethrostomy is classically caused by ischemic necrosis from sutures placed under excessive tension or too close to the delicate urethral mucosal edge, interrupting the marginal blood supply. This leads to fibrosis and luminal narrowing. While spatulation is important in ureteral anastomoses, PU technique relies on precise mucosal apposition. Poliglecaprone 25 is actually appropriate for this procedure; the issue is technique, not material choice.

During exploratory celiotomy in a 4-year-old Labrador, you encounter a mesenteric mass with encasement of a segmental branch of the cranial mesenteric artery. Histopathology later confirms mesenteric lymphoma. Intraoperatively, which vascular principle BEST guides your decision regarding resection margins and bowel viability?

Answer: Mesenteric arterial arcades provide redundant anastomotic flow, so single arcade ligation rarely requires bowel resection

The jejunum and ileum have a rich series of anastomosing arterial arcades (primary, secondary, and in some species tertiary arcades) originating from the cranial mesenteric artery. These arcades interconnect and provide collateral circulation, meaning ligation of a single arcade branch does not necessarily devascularize the bowel it supplies — adjacent arcades can compensate. However, ligation of multiple sequential arcades or the primary trunk eliminates this redundancy and mandates resection. Understanding this arcade anatomy is critical when planning mass excision near mesenteric vessels.

You are performing a tibial plateau leveling osteotomy (TPLO) in a 35 kg dog. Postoperative radiographs show the tibial plateau angle (TPA) has been corrected to 6.5°. Three weeks later the dog is severely non-weight-bearing. Repeat radiographs reveal implant loosening without fracture. Which biomechanical explanation BEST accounts for this complication at an overcorrected TPA?

Answer: Overcorrection reverses the cranial tibial thrust into a caudal tibial thrust, creating a new instability vector that loads the caudal cruciate ligament and alters implant stress distribution

TPLO aims to neutralize the cranial tibial thrust generated by the caudal slope of the tibial plateau during weight-bearing, which is responsible for stifle instability after CrCL rupture. The biomechanical target TPA is approximately 5–7°; however, when overcorrected, the plateau slope actually generates a caudal tibial thrust vector. This reverses the direction of force on the stifle, loading the intact caudal cruciate ligament abnormally and altering the stress pattern on the bone plate and screws, predisposing to implant loosening without necessarily causing visible fracture.

A 9-year-old spayed female Golden Retriever undergoes right lateral thoracotomy for a lung lobe mass. During the procedure, the surgeon notices the lung parenchyma does not fully re-expand after lobe stapling. Intraoperatively, which step is most critical to confirm before chest closure to minimize the risk of persistent postoperative pneumothorax?

Answer: Submerging the staple line under saline with 30 cmH₂O airway pressure applied to detect air leaks at the staple line

The definitive intraoperative leak test is submersion of the staple/resection line under sterile saline while the anesthetist applies sustained positive airway pressure (typically 20–30 cmH₂O). Continuous bubbling identifies staple-line leaks that must be addressed before closure. This is more sensitive and targeted than general pleural irrigation, which may obscure the leak source. A second suture layer is sometimes added prophylactically but does not confirm leak-free closure. Visual inspection of the bronchial stump is useful for lobectomy but does not assess parenchymal staple-line integrity.

A 7-year-old Doberman Pinscher with a history of von Willebrand disease (type I) is scheduled for elective gastropexy. Preoperative vWF antigen level is 18% (reference >60%). Which perioperative hemostatic management strategy is MOST appropriate prior to making the incision?

Answer: Administer desmopressin (DDAVP) 1 µg/kg IV 30 minutes before incision to stimulate endogenous vWF release from endothelial storage granules

In type I von Willebrand disease, endothelial cells retain functional Weibel-Palade bodies containing vWF. Desmopressin (DDAVP) stimulates V2 receptors on endothelial cells, triggering release of stored vWF multimers and acutely raising vWF levels — often 2–3× baseline — within 30–60 minutes. This is the preferred first-line approach for elective procedures in type I vWD. Cryoprecipitate is the most vWF-concentrated blood product and is indicated when DDAVP response is insufficient or for types II/III vWD; however, its administration 4 hours before is suboptimal (it should be given just before incision due to short vWF half-life). FFP contains vWF but at lower concentration and requires large volumes. EACA addresses fibrinolysis, not the primary platelet adhesion defect.