Soft Tissue Surgery PDF

Soft Tissue Surgery 27 CHA P TE R S. Brent Reimer...

Soft Tissue Surgery 27 CHA P TE R S. Brent Reimer and should take place in an area independent of GENERAL INFORMATION the operating room I. Wound classification B. Skin preparation: Antiseptic agents are used to Wounds are classified based on the degree of reduce the bacterial colonization of the surgical contamination. As the degree of contamination in- field before surgery. The preferred agents are creases, the postoperative infection rate can generally bactericidal. Commonly used agents include be expected to increase as well. The “critical” level of chlorhexidine or povidone-iodophor compounds bacterial contamination that begets infection is classi- intermittently rinsed with either sterile saline or cally greater than 105 organisms per gram of tissue, isopropyl alcohol. Chlorhexidine may cause a but variables other than population play a role (i.e., decreased number of skin reactions compared the virulence of the organism, blood supply of tissue with povidone-iodophor compounds. One report involved, host defense mechanisms). Surgeries are states that the use of chlorhexidine scrubs with classified as one of the following four types: isopropyl alcohol rinses is inferior to chlorhexi- A. Clean: A surgically created wound (nontraumatic) dine scrubs with sterile saline rinses not involving the respiratory, gastrointestinal (GI), or genitourinary tract. No breaches in the SUTURE INFORMATION tenets of aseptic technique B. Clean-contaminated: Controlled entrance into the I. Suture materials respiratory, GI, or genitourinary tract, avoiding A. Suture is classified as absorbable or nonabsorb- spillage of contents into the surgical field or with able. Most absorbable suture materials lose much a minor breach in aseptic technique of their tensile strength within 60 days of implan- C. Contaminated: Surgical field subjected to gross tation. Most absorbable sutures undergo tissue spillage of infected tissues or contents of respira- hydrolysis, but some are absorbed via phago- tory, GI, or genitourinary tract. Also seen with a cytosis (e.g., chromic surgical gut) major breach in aseptic technique and in “fresh” 1. Nonabsorbable suture materials include silk, (less than 4 to 6 hours) traumatic wounds nylon, and polypropylene D. Dirty: Traumatic wound with devitalized tissues 2. Absorbable suture materials include polydioxa- or delayed treatment (longer than 4 to 6 hours), none, polyglactin 910, chromic surgical gut, transaction of “clean” tissues encountered during polyglycolic acid, poliglecaprone 25, and surgery to gain access to abscessed tissues polyglyconate II. Antimicrobial prophylaxis B. Suture is further classified as either monofilament Antimicrobial prophylaxis is defined as the adminis- or multifilament (“braided”). Multifilament suture tration of an antimicrobial agent before the contam- materials inherently possess more capillarity, ination event, typically the surgical incision. thus allow more bacteria to “wick” into areas in Therefore, these agents should be given preopera- which they are used. Monofilaments possess less tively 30 and 60 minutes before creation of the of this capillary action and thus are a better incision. However, the continuation of antibiotic choice for contaminated wounds. Multifilament prophylaxis into the postoperative period is indi- suture materials typically have less memory and cated in some very specific circumstances. Deci- often possess better handling characteristics sions regarding which antimicrobial to administer compared with monofilament materials should be directed by anticipated pathogens 1. Monofilament sutures include polydioxanone, present and their susceptibility profile. Currently, poliglecaprone 25, polypropylene, polygly- no evidence has been found that substantiates the conate, and nylon routine continuation of antimicrobial administra- 2. Multifilament sutures include silk, polyglactin tion postoperatively. 910, polyglycolic acid, and chromic surgical gut III. Patient preparation C. Suture can further be classified as synthetic or A. Hair removal: Clipping is preferred over shaving natural (organic) because it incurs less skin trauma. The clipping 1. Natural suture materials include surgical gut should be performed immediately before surgery and silk 368  CHAPTER 27 Soft Tissue Surgery 369 2. Synthetic suture materials include polyglactin 2. Nontraumatic: Most typically associated with 910, polyglycolic acid, polydioxanone, polypro- intact, middle-aged female dogs or young male pylene, and polyglyconate dogs. Presumably associated with a delayed D. Suture selection should be individually tailored to closure of the inguinal ring to allow the testi- the tissue and expected wound environment. In gen- cles to descend eral, the suture should be as strong as, but should D. Scrotal hernia is most common in chondrodystro- not greatly exceed, the tensile strength of the in- phic dogs volved healing tissue. For wounds in which bacteria E. Femoral hernia are anticipated to be present (GI surgery, contami- 1. Male or female dogs are affected nated wounds), typically a monofilament absorb- 2. Can present with a nonpainful swelling over able suture is recommended (e.g., polydioxanone) the mid-thigh or can have vomiting or pain E. Suture patterns include inverting, everting, and with entrapment appositional patterns. Appositional and inverting F. Perineal hernia patterns are most commonly used 1. More common in dogs than cats 1. Inverting suture patterns include the Lembert, 2. Much more common in intact males, link to Halsted, Cushing, Connell, Parker-Kerr, and androgens pursestring 3. Failure of the muscles of the pelvic diaphragm 2. Appositional suture patterns include the simple allows abdominal organs to escape. Omentum interrupted, simple continuous, cruciate, and most commonly entrapped and dogs present Gambee with tenesmus, dyschezia, diarrhea, and a fluc- tuant nonpainful swelling in the perineal region. Can be unilateral or bilateral. Can become an BODY CAVITIES AND HERNIAS emergency if bladder becomes entrapped I. Abdominal cavity 4. Diagnosis: Typically a clinical diagnosis; rectal A. Most commonly approached through a ventral examination is useful in the diagnosis of this midline incision through the linea alba via a mid- disease line celiotomy 5. Herniorrhaphy, most commonly using an B. The holding layer of the abdomen is the external internal obturator roll-up technique. Concur- rectus fascia. It is imperative that this layer be in- rent castration is also highly recommended. cluded in abdominal closures to prevent dehiscence 6. Prognosis: Generally fair to good, but recurrence II. Hernias is relatively common A. Umbilical hernia G. Diaphragmatic hernia 1. Congenital defect believed to be heritable in 1. Can be traumatic (acquired) or congenital some breeds 2. The most common congenital diaphragmatic 2. Often asymptomatic but could have visceral hernia is called a peritoneopericardial entrapment diaphragmatic hernia 3. Herniorrhaphy is the surgical closure of the a. Can occur in cats and dogs hernia b. Can be asymptomatic or cause problems 4. Prognosis is good and recurrences are related to the cardiovascular, respiratory, uncommon or GI tracts B. Cranial pubic ligament hernia c. Direct communication between the abdo- 1. Traumatic avulsion of the cranial pubic liga- men and the pericardial sac ment from the pubic bone d. May be accompanied by concurrent sternal 2. Commonly allows caudal abdominal viscera to defects or, in dogs, cranial abdominal wall escape the abdominal cavity and reside in the hernias. Domestic long-haired cats and subcutaneous tissues Weimaraner and cocker spaniel dogs appear 3. Diagnosis: Suspicion in a patient with abnor- to be predisposed mal swelling near pelvic inlet after a traumatic e. Radiographic signs: Enlarged cardiac event. Bruising of the skin overlying the swell- silhouette, tracheal elevation, loss of ing is also a suspicious finding. Radiographs diaphragmatic border, gas-filled structures may reveal a loss of the “stripe” of the ventral within the pericardial sac abdominal wall on a lateral film as it courses f. Treatment: Surgical herniorrhaphy if clini- toward its typical insertional point on the cally affected. Surgical approach is via a cranial edge of the pubis. Viscera may also be ventral midline celiotomy, which can be ex- readily apparent on radiographs. Abdominal tended into a caudal sternotomy if necessary ultrasound may also be useful g. Prognosis is favorable 4. Treatment: Herniorrhaphy. The avulsed liga- 3. Traumatic diaphragmatic hernias are more ment often has to be secured to holes pre- common than congenital diaphragmatic drilled into the pubic bone to gain purchase. hernias in small animals 5. Prognosis is favorable for patients without a. Motor vehicle accidents are the most com- significant concurrent injuries mon cause but can result from many events C. Inguinal hernia that cause intraabdominal pressure to 1. Traumatic: Can occur in any dog or cat elevate quickly. This causes the lungs to 370 SECTION II SMALL ANIMAL deflate quickly, which creates a significant the abdomen. The rent is then sutured, typi- pressure differential between the abdominal cally in a simple continuous pattern. A thora- and pleural compartments. This causes the costomy tube is placed to facilitate reestab- diaphragm to be under significant stress, lishment of negative intrapleural pressure and ruptures can occur g. Prognosis: Typically good in patients that b. Patients with diaphragmatic hernias are can be stabilized. Recurrence is uncommon often in shock as a result of the traumatic event. Concurrent injuries are common and SURGERY OF THE INTEGUMENT should be looked for; may present with dys- pnea, tachypnea, cyanosis, or tachycardia I. Wounds c. Physical examination may reveal dull heart A. Healing of the integument is influenced by the and lung sounds, intrathoracic borborygmi wound environment as well as host factors. The as a result of GI organs being present in the healing of wounds occurs in the following over- thoracic cavity, minimal ability to generate lapping phases: meaningful chest excursions, significant ab- 1. Inflammatory phase. Occurs immediately after dominal component to respiration, and po- the wound has been created tentially an abdomen that appears “deflated,” 2. Debridement phase. Host cells remove damaged which is due to the abdominal contents now or necrotic tissue residing in the thoracic cavity 3. Repair phase. Generally begins several days d. Initial patient stabilization is often necessary. after the injury This is accomplished by providing oxygen B. Most surgical wounds are weakest during the “lag supplementation, potentially elevating the phase” of wound healing, which occurs 3 to cranial end of the patient in an effort to en- 5 days after surgery. Most surgical dehiscences courage thoracic contents to “leak” back into occur during this time the abdomen. Pleural effusion is commonly C. Host factors that slow wound healing include ex- present and can be removed via thoracocen- cessive glucocorticoid levels (either endogenous tesis in an effort to improve breathing or exogenous), diabetes mellitus, malnourishment, e. Diagnosis is obtained via plain radiographs and hypoalbuminemia most commonly. A loss of the diaphrag- D. Wounds can heal via several different mechanisms: matic line may be appreciated; a loss of the 1. Primary closure. Surgical closure of viable cardiac silhouette, displacement of the tissue without delay lungs by soft tissue or fluid opacity struc- 2. Delayed primary closure. Typically contami- ture, or presence of gas-filled GI organs can nated wounds. Wound cleaned and lavaged also be seen on occasion. If a definitive di- for 2 to 5 days after surgery until contami- agnosis is not yet obtained, a water-soluble nation is under control, and then wound positive contrast agent can be injected into closure is performed the peritoneal cavity in a procedure called a 3. Secondary closure. Wound maintained as an positive contrast celiogram. An abnormal open wound and closed subsequent to gran- communication between the abdominal and ulation tissue formation (more than 5 days thoracic cavities would allow contrast agent after creation of the wound) to enter the thoracic cavity. An upper GI 4. Second-intention healing. Wound allowed study using barium administered per os to heal via granulation, wound contraction, may also reveal loops of intestine within the and epithelialization without surgical thoracic cavity. Ultrasound may also be use- manipulation ful in obtaining the diagnosis if necessary II. Specific diseases of the integument f. Treatment: Mechanical ventilation is neces- A. Neoplasia sary during this procedure. Patient should be 1. Mast cell tumors: Most common cutaneous stabilized before being taken to surgery to malignancy of dogs. All are considered malig- correct. Patients with gastric entrapment nant in dogs. Exist as grade 1, 2, or 3, with the may be at an increased risk for acute respira- higher the grade indicating a more anaplastic tory decompensation resulting from progres- and biologically aggressive tumor. Typically sive gastric distension. These patients should occur in the skin but can also occur in the be monitored closely and potentially taken to bone marrow or internal organs (liver, spleen, surgery on an emergency basis. Surgical cor- GI tract). In cats, cutaneous mast cell tumors rection is achieved via ventral midline celiot- are typically benign and have a predisposition omy. Rarely, this incision needs to be ex- for the head and neck. Visceral involvement in tended into a caudal sternotomy. The rent is cats indicates malignancy identified, and gentle traction is placed on the a. Signalment: Predisposition in certain breeds herniated organs to place them back into the (boxers, pugs, and Boston terriers). Gener- abdomen. The liver is the organ most com- ally middle-aged or older animals monly herniated through the diaphragm. b. Diagnosis: Described as the “great imitator” Occasionally, the rent needs to be enlarged to because of its tendency to have no typical allow the herniated organs to be replaced into or highly predictable appearance. Should be  CHAPTER 27 Soft Tissue Surgery 371 considered a differential diagnosis for any encountered, as well as the constant use of the cutaneous or subcutaneous mass. Mass can oral cavity for daily activities (e.g., eating, increase and decrease in size as a result of swallowing saliva) degranulation of intracellular histamine C. Neoplasia of the oral cavity granules. Typically exfoliates cells readily 1. Malignant melanoma: Most common oral on fine-needle aspirate (FNA) to obtain diag- tumor of dogs. Aggressive locally and is often nosis. Cytology reveals a round cell popula- metastatic. Treatment centers on removing the tion with granules commonly seen. Grade local disease and on appropriate staging. can only be obtained via histopathological Long-term prognosis is poor appearance via biopsy 2. Squamous cell carcinoma: Most common oral c. Treatment: Wide surgical excision is the tumor of cats; occur with frequency in dogs. treatment of choice. Classically, 3-cm Locally invasive and can metastasize. Treat- margins have been recommended. This ment centered on removal of the local disease recommendation was based primarily on and staging. Can be tonsillar in dogs. Prognosis empirical thought rather than scientific is guarded in dogs and grave in cats evidence. Recent reports may support less 3. Fibrosarcoma: Locally aggressive but late to aggressive surgical margins as being as metastasize. Treatment primarily involves wide effective. Classically chemotherapeutic excision of the primary tumor interventions centered on prednisone or 4. Osteosarcoma: Locally aggressive and high vinblastine have been used. May also need metastatic potential. Prognosis in dogs is a histamine 2 (H2) blocker if the increased poor but typically better than appendicular levels of H2 in the blood are causing GI osteosarcoma ulceration. May respond to radiation 5. Epulides: Most common class of benign oral therapy tumors. Three types: Acanthomatous (most d. Prognosis: Good with successful removal of common), fibromatous, and ossifying exist. masses with clean margins. Guarded to Arise from the periodontal ligament. Treat poor with grade 3 tumors or tumors which with excision or radiation therapy have already metastasized (regional lymph 6. Ameloblastoma: Benign; arise from dental nodes most commonly) lamina. Young dogs 2. Mammary masses: Uncommon in male dogs 7. Oral papillomatosis: Benign process, typically and male cats but can occur. Most common tu- younger dogs. Viral cause. Usually multiple mor in female dogs. Cause is unknown but gray masses on gingival or buccal mucosa. linked to hormonal influences, so decreased in- Typically requires no surgical intervention and cidence in dogs spayed early in life. Approxi- spontaneously regresses mately 50% are malignant in dogs, between 80 D. Cleft palate: Brachycephalic dogs and Siamese and 90% are malignant in cats cats are predisposed. Often diagnosed at birth a. Signalment: Typically intact females or fe- but may manifest because of difficulty nursing, males spayed late in life milk coming from nostril during nursing, pneumo- b. Diagnosis: Often a palpable mass in the nia (aspiration), small stature, or a failure to mammary chain. Normal dogs have five thrive mammary glands on each side; cats nor- 1. Primary cleft: Lip and premaxilla (harelip) mally have four glands on each side. FNA 2. Secondary cleft: Cleft in the hard and soft may be diagnostic palate c. Treatment: Surgical excision of the disease. 3. Treatment: Surgical correction of the defect In dogs, typically a lumpectomy or mam- using local tissue flaps most commonly. mectomy is performed for smaller masses. Prognosis is fair, but multiple surgeries In cats, more aggressive surgery is indicated should be anticipated to revise defect and typically takes the form of bilateral E. Salivary mucocele: Also called a sialocele, or radical mastectomy salivary cyst. Dogs have four paired sets of salivary d. Prognosis: Depends on histologic type, glands, including the zygomatic, parotid, mandibu- stage of disease, and ability to resect lar, and sublingual. The mandibular salivary gland diseased tissue duct courses from the gland rostrally and is contin- uous with the sublingual chain. These glands eventually empty at the rostral aspect of the lingual SURGICAL DISEASES OF THE GI TRACT frenulum. These are the glands most commonly I. Oral cavity affected by a salivary mucocele. Four A. The oral cavity is inherently contaminated with individual presentations can occur: bacteria but also has a robust blood supply. Con- 1. Nonpainful ventral cervical swelling sequently, healing typically occurs despite the 2. Pharyngeal swelling, which can lead to contaminated environment profound dyspnea B. Surgery within the oral cavity has an increased 3. Rannula, submucosal swelling under the tongue risk of wound dehiscence as a result of the 4. Exophthalmia, which is due to retrobulbar inherent contamination, increased tension often leakage of the zygomatic gland 372 SECTION II SMALL ANIMAL 5. Diagnosis typically derives from clinical predisposed. Multiple littermates may be presentation and findings. Aspiration of the affected. May remain of small stature and grow swelling (if performed) yields viscous fluid rich more slowly than unaffected littermates. Ventral in protein with neutrophils associated with the cervical swelling can be observed near the tho- inflammation. Can also perform contrast racic inlet corresponding to dilated esophagus. sialogram if needed to confirm diagnosis or May be coughing if have concurrent aspiration determine which side is affected pneumonia. There are several different vascular 6. Treatment: Excise the affected gland(s). ring anomalies, but the persistent right aortic Prognosis is excellent with surgery. Repeated arch is the most common and accounts for more drainage of the mucocele is very rarely than 90% of the vascular ring anomalies effective in resolving the disease 1. Diagnosis: Radiographs typically show a dila- F. Salivary gland neoplasia: Rare disease. Typically tion of the esophagus cranial to the base of the malignancy. Treatment via surgical excision heart. Also want to rule out concurrent aspira- II. Esophagus tion pneumonia. Contrast studies may also A. Animals afflicted with esophageal disease can be useful. Echocardiography may be useful in exhibit ptyalism, regurgitation, coughing determining the abnormal vessel(s) involved (particularly with secondary aspiration 2. Treatment: Surgical transection of the con- pneumonia), dysphagia, weight loss, or may stricting vessel. For a persistent right aortic be recumbent if severely debilitated arch, this is accomplished through a left lateral B. The esophagus does not heal as readily as many thoracotomy performed at the fourth intercos- of the other areas of the GI tract because of its tal space decreased vascularity that results from its 3. Prognosis: Typically good; esophageal motility segmental blood supply as well as the fact that problems can persist the esophagus lacks a serosal layer, is in constant G. Cricopharyngeal achalasia: Disorder of swallow- motion with day-to-day activities such as ing where food bolus that has formed in the breathing and swallowing, and does not typically mouth is not allowed to enter the esophagus have access to the omentum to accentuate the because of failure of the cricopharyngeal muscle healing process to relax during swallowing. Springer and cocker C. Esophageal foreign bodies: Typically younger spaniels are predisposed. Typically diagnosed at animals. Bones, rawhides, toys, fishhooks. Most weaning commonly lodge at the thoracic inlet, base of the 1. Diagnosis: Clinical signs, dynamic contrast heart, or near the diaphragm studies of the patient swallowing 1. Diagnosis: Radiographs, contrast studies, 2. Treatment: Cricopharyngeal myectomy esophagoscopy 3. Prognosis: Guarded to fair 2. Treatment: Preferable to remove the foreign H. Hiatal hernia: Protrusion of the abdominal portion body endoscopically; if that is not possible, of the esophagus as well as potentially portions then removal by surgical intervention of the stomach through the esophageal hiatus 3. Prognosis: Good if esophagus is healthy; if in the diaphragm into the caudal portion of the damaged, esophageal stricture can result thorax. Shar-peis and brachycephalic breeds are D. Esophageal strictures: Can be intraluminal or predisposed extraluminal compressions. Can be the result 1. Diagnosis: Radiographs, but the condition can of many insults, including previous esophageal be dynamic and so can have normal radio- surgery, esophagitis, or neoplasia. Has also been graphs and a hiatal hernia still be present linked to administration of certain medications 2. Treatment: Medical management with H2 block- (e.g., doxycycline capsules in cats) because of the ers, gastroprotectants. If no positive response caustic medications maintaining mucosal contact to medical management, surgical correction for an extended period via gastropexy and hiatal reduction is needed 1. Diagnosis: Radiographs, contrast studies, 3. Prognosis: Typically good. esophagoscopy III. Stomach 2. Treatment: Esophageal resection and anasto- A. Gastric dilatation-volvulus (GDV) syndrome: An mosis, bougienage extremely serious medical condition that results 3. Prognosis: Guarded because recurrence is from the stomach rotating to varying degrees on common its own axis. Gas subsequently becomes trapped E. Esophageal neoplasia: Rare in cats and dogs. Typ- within the gastric lumen and cannot escape. The ically progressed at time of diagnosis. Has been stomach dilates, which subsequently compresses linked with Spirocerca lupi infestation the systemic and portal venous systems within F. Vascular ring anomalies: Result from persistence the abdomen. This significantly decreases cardiac of embryologic structures that normally regress return, and the patients become cardiovascularly in utero. Patients affected most commonly pres- unstable because of their functional hypovolemia. ent for regurgitation, which typically begins This condition represents a surgical emergency! shortly after weaning to solid foods, which (Figure 27-1) cannot pass the constriction. Irish setters and 1. Signalment: Typically middle-aged large- or German shepherd dogs are breeds that are giant-breed dogs. Dogs with a deep-chested  CHAPTER 27 Soft Tissue Surgery 373 gastrocentesis can be performed using a large hypodermic needle or a large IV catheter. After the gas has escaped the stomach using this technique, reattempting to pass the orogastric tube may be successful because the gastric pressure is typically reduced. Temporary gas- trostomy has also been successful in patient stabilization in rare instances when previous attempts to decompress the stomach have been unsuccessful. Once the patient is stable, surgical intervention should be performed im- mediately on obtaining a definitive diagnosis. Stabilization takes precedence over diagnostic testing 5. Surgery a. Reposition stomach b. Assess tissue viability and resect any necrotic or questionable tissue (1) Color: Pink and red are acceptable; dark tissue is not. This can occasionally be misleading if the serosal surface Figure 27-1 Direction of gastric rotation in most dogs with gastric dilata- appears normal, but the intraluminal tion volvulus (GDV). (From Fossum TW et al. Small Animal Surgery, 3rd ed. surface may be necrotic St Louis, 2007, Mosby.) (2) Pulses (3) Palpation: Viable tissue should not be overly thin and friable conformation are predisposed. Having a first- (4) Bleeds on cut surface: Can be mislead- degree relative with a history of GDV is a risk ing, and correct interpretation is critical factor for this disease; however, can occur in c. Prevent recurrence via gastropexy. Many any dog different techniques exist, and the choice is 2. History: Typically, acute onset of vomiting, based largely on surgeon preference. The which can be either productive or non produc- gastropexy should create a permanent adhe- tive, lethargy, abdominal pain, apprehension, sion between the patient’s abdominal body ptyalism. May coincide with recent exercise wall and pyloric antrum. This means that after a meal but not consistently the gastropexy should be performed on the 3. Diagnosis: Clinical picture of acute onset of patient’s right side. Described techniques cardiovascular compromise in a previously include incisional, belt-loop, circumcostal, healthy dog of classic conformation is support- gastrocolopexy, and tube gastrostomy ive of the diagnosis. May have distended abdo- 6. Postoperative care: Cardiac rhythm abnormali- men, but possibly not, because the dilated ties are common in patients with this disease. stomach may lie completely recessed under The most common arrhythmia is the occur- the ribs and not be palpable. Radiographs are rence of premature ventricular contractions, useful for diagnosis, with the right lateral ra- which can occur preoperatively, intraopera- diograph typically showing the classic signs of tively, or postoperatively. Interventional cues gastric compartmentalization (“double and treatments are covered elsewhere bubble”) and gastric malposition 7. Prognosis: Good with early identification and 4. Treatment: Stabilization is of paramount impor- aggressive therapy. Negative prognostic factors tance. Several large-bore intravenous (IV) cath- include the presence of gastric necrosis and a eters should be placed in the patient. The cath- blood lactate greater than 6 mmol/L at admis- eters should not be placed in the hindlimbs, as sion. Recurrence is exceedingly rare with an blood from the caudal portions of the body is appropriate gastropexy not typically reaching the heart effectively. Of- B. Gastric foreign bodies ten in obstructive shock and should have intra- 1. Presentation: Many will present with vomiting, vascular resuscitation performed immediately anorexia, diarrhea, and a painful abdomen. with either crystalloids or colloids or a combi- Severity of clinical signs will vary considerably nation. Can also have respiratory compromise depending on degree of obstruction, time because of a large stomach decreasing tho- obstruction has been present, degree of racic expansion for respiration and may benefit dehydration, and other factors from oxygen supplementation. Gastric decom- 2. Diagnosis: History of a missing toy or house- pression should also be attempted. A large- hold item; vomiting may be severe. Radio- diameter orogastric tube should be passed graphs may reveal an obvious foreign body. into the stomach to allow the entrapped gas to Positive contrast agents can be administered escape. If this is not successful, percutaneous to further assist with the diagnosis. If the 374 SECTION II SMALL ANIMAL foreign body is obstructing the gastric outflow IV. Small intestine tract and the animal is losing gastric secretions A. Intestinal foreign bodies in the vomitus, the patient may have an hypo- 1. Relatively common medical condition of dogs chloremic, hypokalemic metabolic alkalosis and cats. Typically result from dietary indiscre- 3. Treatment: Smaller gastric foreign bodies may tion. Can be the result of a simple item (e.g., pass through the GI tract without assistance. toy, bone, stone) or from the patient ingesting If this technique is selected, patients must be a string (e.g., thread, dental floss, rope), in monitored closely for signs of declining condi- which case it is called a linear foreign body. In tion, in which case surgical intervention would the case of a linear foreign body, the string have to be performed. Some will attempt to in- gets lodged in one area of the GI tract, but duce vomiting in an effort to have the patient peristalsis continues unabated. This causes expel the foreign body themselves, but the the intestinal tract to slide up the string and success rate is unknown and thought by many accordionate. Classically, linear foreign bodies to be low. The vomiting may also exacerbate are associated with cats; thus a part of the underlying esophagitis and can lead to aspira- physical examination of any vomiting cat in- tion pneumonia. Definitive therapy involves cludes close examination under the tongue to removal of the foreign body via gastroscopy look for string caught under the tongue or exploratory laparotomy and gastrotomy. a. Presentation: Most commonly younger Rarely is the stomach damaged to the point animals suffer from dietary indiscretion, where a partial gastrectomy is necessary. Al- but any animal may have an intestinal for- ways perform an entire abdominal exploratory eign body. Most commonly, the patients surgery to ensure that other foreign bodies are have vomiting, diarrhea, anorexia, and not present at other levels within the GI tract. lethargy. If the intestine has perforated, The holding layer throughout the GI tract is the the animal may show varying degrees of submucosa and must be incorporated into the shock and could have a palpable fluid gastrotomy closure. Gastrotomy closure can wave. This would be the result of septic be performed numerous ways, including a peritonitis. These patients should have one-, two-, or three-layer closure. Appositional immediate stabilization and subsequent or inverting suture patterns are typically used. exploratory surgery as soon as they are Monofilament absorbable suture material is stable enough to endure general anesthesia recommended b. Diagnosis: Abdominal palpation may reveal C. Gastric masses a palpable foreign body. Abdominal radio- 1. Benign masses may occur in the stomach. graphs may show an obstructive pattern Leiomyomas arise from the smooth muscle of in the small bowel or enteroplication in the the stomach. Chronic hypertrophic pyloric case of a linear foreign body. Contrast stud- gastropathy occurs most commonly in small- ies can aid in the diagnosis if necessary, as breed dogs and is typically acquired later in can abdominal ultrasound life. The cause is unknown. Treatment of these c. Treatment: As with gastric foreign bodies, conditions can be instituted by marginal medical management can be attempted on resection of the tissue involved. Prognosis rare occasions, but typically these patients is favorable. will require surgical intervention. Full ab- 2. Most gastric neoplasms are malignant in dominal exploratory should be performed dogs and cats. Adenocarcinoma is the most and the foreign body isolated. Viability of common gastric neoplasm in dogs, whereas the bowel should be assessed. If the bowel lymphoma is the most common neoplasm is viable, then a simple enterotomy can be in cats performed. The enterotomy is typically best a. Presentation: Typically older animals. performed immediately aborad to the ob- Clinical signs are often nonspecific and struction in an effort to perform the surgery center around vomiting, anorexia and on only healthy bowel that has not experi- weight loss enced any degree of vascular compromise. b. Diagnosis: Radiographs rarely will reveal a If the bowel has questionable viability, a mass. Contrast radiographs and abdominal resection and anastomosis should be per- ultrasound may be useful in the diagnosis of formed. An end-to-end anastomosis of the this disease remaining ends of small intestine should be c. Treatment: Wide surgical resection of the performed and is preferable to an end- diseased tissue. Typically disease is ad- to-side or side-to-side variety. Suture mate- vanced at diagnosis, so biopsies of the liver rial should be a monofilament, absorbable and regional lymph nodes are also recom- variety of appropriate size. Healing of mended. The mass may involve the pylorus, surgical sites can be enhanced by an omen- the biliary system, or both. A rerouting topexy or performing a serosal patch to of the GI system or biliary tree may be the area necessary d. Prognosis: Typically, the prognosis is good. d. Prognosis: Typically poor Low serum protein levels and the presence  CHAPTER 27 Soft Tissue Surgery 375 of preoperative septic peritonitis may pre- C. Intussusception dict patients that may be at a higher risk for 1. Occurs when one segment of bowel telescopes intestinal dehiscence and subsequent septic into an adjacent segment. The inner segment is peritonitis typically the portion on the orad side of the le- B. Septic peritonitis sion and is called the intussusceptum; the outer 1. Diagnosis: Documentation of bacteria living in segment is typically the more aborad segment the peritoneal cavity. Most commonly diag- and is called the intussuscipiens (Figure 27-2) nosed with cytology confirming the presence 2. Signalment: Typically younger animals, although of intracellular or extracellular bacteria or older animals can be affected. There is an both or food or plant material on abdomino- underlying cause in almost all patients, and it is centesis. A diagnostic peritoneal lavage may crucial to identify and treat it. In younger ani- assist with the diagnosis in cases where mals, intestinal parasitism is the most common patients lack a plethora of free abdominal fluid. cause, whereas in older animals it is often Comparisons of glucose and lactate levels in neoplasia. Other potential causes include enteri- the abdominal fluid with concurrent blood tis (viral, bacterial), recent surgery, or trauma. values may also assist with the diagnosis. May German shepherd dogs may be predisposed have a left shift on leukogram and could 3. History: Vomiting, diarrhea, may have blood in potentially be hypoglycemic stool. Abdominal pain. May have an acute or 2. Causes: Most commonly due to a ruptured chronic history as some intussusceptions may viscous. GI rupture is the most common cause be present for a considerable time before they in dogs and cats. Other causes would be rup- are diagnosed ture of an infected level of the biliary system, 4. Diagnosis: May have a palpable mass in the ab- rupture of an area of the urogenital tract, pene- domen. Radiographs typically reveal an obstruc- trating wound seeding the abdomen, iatrogenic tive intestinal pattern and potentially may reveal in a postoperative patient a soft tissue mass corresponding to the intus- 3. Treatment: Medical stabilization such as susception. Abdominal ultrasound is useful in IV fluid support, antibiotics based on bacterial the diagnosis of an intussusception. Occasion- identification or empirical selection based on ally, the intussusceptum migrates completely suspected pathogen, identification of the cause through the colon and can be seen protruding of the septic peritonitis, surgical exploration of from the anus. These must be differentiated the abdominal cavity, and repair or removal of from a rectal prolapse via probing between the damaged organs protruding organ and the anus itself. If it is a 4. Prognosis: Typically guarded to fair. Highly rectal prolapse, the probe will not be able to be dependent on patient stability, promptness passed into the anus, whereas if it is an intussus- to identification, and subsequent surgical ception the probe will pass easily between the intervention intussusceptum and the anus A Intussuscipiens Apex Neck Intussusceptum B Figure 27-2 A, Configuration of an intussusception: Neck, intussusceptum, apex, intussuscipiens. B, To reduce an intussusception, place traction on the neck as you milk the apex out of the intussuscipiens. (From Fossum TW et al. Small Animal Surgery, 3rd ed. St Louis, 2007, Mosby.) 376 SECTION II SMALL ANIMAL 5. Treatment: Surgical exploration and attempted 2. Treatment is centered on surgical resection. manual reduction of the intussusception Aggressiveness of the surgery is determined (Figure 27-2). If the intussusception cannot be by the tissue type of the mass being treated reduced or the bowel has questionable viabil- and can vary from simple mucosal resection ity, then an intestinal resection and anastomo- to colonic resection and anastomosis sis is performed. Enteroplication is the D. Megacolon: More common in cats than in dogs. process of suturing adjacent loops of bowel to Causes include idiopathic (most common cause), each other through intermittently placed pelvic narrowing often due to malunions of pelvic partial-thickness sutures. This is thought by fractures, neurologic abnormalities, or endocrine some to decrease the incidence of the patient disorders. Cats can present with constipation sustaining another intussusception. Must (difficult or infrequent passage of abnormally identify and treat underlying condition dry feces) or obstipation (passage of no feces). 6. Prognosis: Generally good if patient is stable They may also have anorexia, vomiting, and D. Intestinal neoplasia even diarrhea if liquid feces can pass around 1. Most intestinal masses are malignant, with the massive firm intraluminal concretions adenocarcinoma and lymphoma being the 1. Signalment: Typically acquired in middle-age most common types or older. Occurs more often in cats than in 2. Treatment: Resection and anastomosis most dogs commonly 2. History: Generally progressive constipation 3. Prognosis: Typically guarded to poor eventually leading to obstipation E. Intestinal volvulus 3. Diagnosis: Often diagnosis can be obtained via 1. Condition when mesenteric attachment of the history and physical examination findings of intestine twists around on itself and restricts a large colon distended by very firm feces. venous drainage most commonly. Eventually Support for the diagnosis can be garnered by leads to necrosis of the affected bowel. Can abdominal radiographs affect the entire bowel served by the cranial 4. Treatment mesenteric artery (descending duodenum, je- a. Medical intervention: Typically performed junum, ileum, ascending and transverse colon) before surgical intervention is attempted. or smaller portions of the bowel (Figure 27-3) Patients often have to undergo general 2. Typically painful and may be in shock. German anesthesia and manual evacuation at shepherds overrepresented initial diagnosis to empty colon. Enemas 3. Treatment: Immediate surgical exploration assist in the initial deobstipation as well 4. Prognosis: Guarded as in maintenance of patients long term. V. Colon, rectum, and perineum Increasing fiber content of the diet via A. Because of the higher rate of complications asso- either a specially formulated diet high in ciated with colonic surgery, attempts are typically fiber or by adding fiber to the diet is also made to minimize colonic surgical interventions. attempted. Stool softeners, laxatives, and The higher rate of complications is directly re- prokinetic drugs (e.g., cisapride) can also lated to the much higher concentration of bacte- be administered ria in the colon compared with other levels of the b. Surgical intervention: Typically performed GI tract. As such, when a foreign body is palpated in animals who do not respond to medical in the colon during an exploratory surgery, it is intervention, animals that become refrac- recommended that the item be “milked” down to tory to medical intervention, or in animals the level of the anus and manually extracted in- with owners unwilling to perform the med- stead of performing a colotomy to remove it ical interventions necessary. Surgical cor- B. Rectal prolapse: Protrusion of the distal colon and rection consists of a subtotal colectomy in rectum from the anus. Varying degrees of involve- which the vast majority of the patient’s ment can be present in a patient. Typically, there is colon is removed via resection and either an underlying cause such as parasitic infestation or the ileum or very orad portion of the neoplasia. Treatment first attempts to replace the colon is brought into apposition with the prolapsed tissue into the rectum and placing a very aborad portion of the colon remain- loose pursestring suture for between 3 and 5 days ing near the pelvic inlet. Cats are expected to maintain the tissue within the rectum to have varying degrees of diarrhea post- 1. Occasionally, necrotic tissue may need to be operatively, which typically resolves be- resected tween 1 and 2 months. Prognosis with 2. Recurrent episodes can be treatment by a surgical intervention is good colopexy where the colon is permanently fixed E. Anal sacculitis to the body wall by placing sutures between 1. Fairly common disease of dogs and can occur the descending colon and the left body wall in cats C. Colonic masses: Benign adenomatous polyps and 2. Clinical signs: Licking, tenesmus, irritation, adenocarcinomas are the most common masses scooting 1. Most are present after an owner notices blood 3. Diagnosis: Rectal examination may reveal in the stool or straining impacted and thickened anal sacs  CHAPTER 27 Soft Tissue Surgery 377 Ileocolic artery Transverse colon Ascending colon Aorta Descending colon Cecum Cranial mesenteric artery Duodenum Jejunum Ileum Jej Jejunal un arteries um Bowel distention Hernia ring Impaired venous return Arterial transport of blood Leakage of Rapid absorption intraluminal and systemic contents distribution of Edema, anoxia, sequestration of blood resulting in toxins and bacteria Necrosis peritonitis Blood loss— Changes in bacterial flora intraluminal and extraluminal and massive increase in numbers of organisms Loss of intestinal barrier, increased permeability Figure 27-3 Pathophysiologic events associated with strangulating intestinal obstructions. (From Fossum TW et al. Small Animal Surgery, 3rd ed. St Louis, 2007, Mosby.) 4. Treatment: Manual evacuation of anal sac con- F. Anal sac masses tents on a regular basis to prevent impaction. 1. By far the most common is the anal sac Some evidence of an immune-based compo- adenocarcinoma nent, so some will provide a hypoallergenic 2. Signs: Can present after owner notices a swell- diet. If problems persist, then surgical inter- ing in the perineal region; can be polyuria vention can be performed via open or closed or polydipsia (hypercalcemia is seen as a anal sacculectomy common paraneoplastic syndrome with this 378 SECTION II SMALL ANIMAL disease), tenesmus, lethargy, passage of com- 3. Most commonly have signs associated with pressed feces. Females may be predisposed one or more of three body systems: 3. Diagnosis: Rectal examination, FNA of mass a. GI: Vomiting, diarrhea, anorexia, failure to can be performed. Metastasis is common with thrive this tumor, particularly to the regional (medial b. Urinary: Associated with ammonium biurate iliac) lymph nodes so staging via abdominal crystals and urate stones ultrasound is recommended c. Neurologic: Seizures, depression (particu- 4. Treatment: Surgical removal of the mass, with or larly after high-protein meals), stuporous without removal of the medial iliac lymph nodes behavior. Can sustain a prolonged recovery 5. Prognosis: Guarded to poor, median survival after general anesthetic events time between 6 and 12 months 4. Signalment and physical examination findings: G. Perianal masses Typically small stature, may have been the 1. Perianal adenoma “runt”; failure to grow normally, may have re- a. Most are hormonally responsive and seen tained canine teeth, and cryptorchidism. Physi- almost exclusively in intact male dogs cal examination generally yields small stature, b. Diagnosis: FNA of the mass reveals cells poor body condition, and small liver that have the appearance of liver cells, so 5. Laboratory findings it is also known as a hepatoid adenoma a. Complete blood cell count (CBC): Microcytic c. Treatment: Resection of the masses and anemia, may have white cell alterations castration b. Serum chemistry: Low albumin, low blood d. Prognosis: Excellent urea nitrogen, low cholesterol, low glucose, 2. Perianal adenocarcinoma low globulins. With congenital shunts, liver a. Often large, aggressive, and anaplastic enzymes are typically normal or mildly b. Not linked to hormonal influence increased, with acquired shunts liver en- c. Treatment: Resection zymes are typically elevated as underlying d. Prognosis: Guarded liver disease is the cause of these shunts VI. Liver c. Urinalysis: Typically low specific gravity to A. Portosystemic shunts urine owing to decreased amount of urea 1. Can be congenital (more common) or ac- available to provide renal medulla with quired. Congenital shunts are most commonly osmotically active substrate for countercur- single vessels; acquired shunts are most com- rent mechanism in the loop of Henle. May monly multiple have ammonium biurate crystals 2. Can be extrahepatic (more common) or intra- 6. Other diagnostics hepatic (Figure 27-4) a. Abdominal radiographs: Small liver, poten- a. Classically, small-breed dogs have been as- tially enlarged kidneys sociated with extrahepatic, and large-breed b. Abdominal ultrasound: Operator dependent dogs have been associated with intrahe- but may reveal presence, location, and patic shunts. Yorkshire terriers, pugs, morphology of the shunt poodles, Labrador retrievers, and Irish c. Serum bile acids: Typically fasting sample wolfhounds are predisposed within reference range or slightly increased; b. Cats can also have portosystemic shunts. postprandial sample usually tremendously Their signs are most commonly associated elevated with the neurologic system (blindness, ptya- d. Nuclear scintigraphy: Will provide informa- lism, seizures) and has been purported to tion regarding the presence or absence of a be linked with copper-colored irises. A shunt, but information regarding location cause for this link is unknown and morphology of the shunt is minimal Figure 27-4 Schematic representation of an extrahepatic portacaval shunt and an intrahepatic portacaval shunt. (From Birchard SJ, Sherding RG, editors. Saunders Manual of Small Animal Clinical Practice, 3rd ed. St Louis, 2006, Saunders.)  CHAPTER 27 Soft Tissue Surgery 379 e. Contrast portography: Radiopaque material overly pessimistic regarding finding liver nod- is injected into the portal system and either ules until histopathology confirms diagnosis traced into the liver in a normal animal, or 3. Hepatocellular carcinoma: Most common it will outline the abnormal communication primary liver tumor of dogs between the portal and systemic circula- 4. Cholangiocellular adenoma: Most common tions. Typically requires general anesthesia, primary liver tumor of cats minor surgical procedure to catheterize a 5. Treatment: Liver lobectomy jejunal or splenic vein, and then injection of 6. Prognosis: Dependent on underlying disease the material. Provides confirmation of the C. Liver-lobe torsion: Rare disease, most common in presence or absence of a shunt as well as left lateral lobe; lobectomy is treatment of choice useful morphologic information D. Liver abscess: Rare disease, serious medical 7. Treatment condition, treatment via lobectomy a. Medical management: Associated with a VII. Pancreas poorer survival time than surgical intervention A. Pancreatitis is a potential sequela to pancreatic but can be used in patients to stabilize before manipulations during surgery. Typically the in- surgery or for owners that decline surgery flammation is mild and self-limiting, but clinically (1) Low-protein diet significant inflammation can occur with robust (2) Antibiotics to control colonic flora handling of the pancreas (metronidazole, neomycin, potentiated B. Insulinoma: -cell tumor, insulin-secreting tumor penicillins) 1. Signalment: Typically larger-breed dogs (3) Lactulose to decrease intestinal transit (golden retriever, Labrador retriever), time to decrease the time available to middle-aged or older generate toxic byproducts of protein 2. History: Episodes of weakness, collapse, or digestion as well as to trap ions block- seizures, which may or may not be associated ing transport across the intestinal wall with exercise or meals via acidification of the colonic contents 3. Physical examination is typically unremarkable (4) Anticonvulsants if necessary to prevent but occasionally may find a poor body condi- seizures tion or signs of neuroglycopenia ramifications b. Surgical intervention: Identify the shunt, 4. Diagnostics: Hypoglycemia in the face of then address vessel concurrent normal or often increased insulin (1) Simple suture ligation: Can cause portal levels. Can use abdominal ultrasound to hypertension if the portal system can- attempt to locate mass within pancreas not compensate for increased circula- 5. Treatment tion immediately. Can measure portal a. Medical management pressures to predict (1) Prednisone (2) Ameroid constrictor: Inner casein (milk (2) Small, frequent meals protein) ring and outer stainless steel (3) Limit exercise ring. Outer ring restricts outward expan- (4) Diazoxide sion of the protein as it imbibes fluid (5) Streptozocin within the peritoneal cavity, forcing all b. Surgical intervention expansion to occur inward (1) Exploratory surgery with partial pancre- (3) Bands made of cellophane, which atectomy is preferred causes inflammation within vessel and (2) Biopsy regional lymph nodes and liver subsequent thrombosis to stage disease (4) Obtain a liver biopsy to rule out under- 6. Prognosis: In dogs, almost all are malignancies so lying primary liver disease long-term prognosis is guarded to poor. Improved 8. Postoperatively animals should be closely survival times are seen with surgery compared monitored for the following: with medical management a. Hypoglycemia b. Portal hypertension SURGICAL DISEASES c. Disseminated intravascular coagulation OF THE URINARY TRACT d. Seizures e. Hemorrhage I. Kidneys: Nephrectomy 9. Prognosis: Better with surgery over medical A. Performed for severe trauma to the kidney, cata- management. Good prognosis with congenital strophic infection of the kidney, renal neoplasia extrahepatic. Fair with congenital intrahepatic B. Unilateral nephrectomy causes no untoward as higher perioperative mortality rate. Guarded effects on the patient long-term assuming a with acquired shunts, as typically significant normally functioning kidney remains in the liver disease is the underlying cause patient postnephrectomy B. Liver masses II. Ectopic ureters 1. Metastatic disease is more common in dog and A. Diagnosed in females more commonly than in males cat livers than is primary liver neoplasia B. Diagnosed in dogs more commonly than cats. 2. Regenerative nodules are a normal and com- Labradors, soft-coated wheaten terriers and mon finding in older patients. Avoid being Siberian huskies are overrepresented 380 SECTION II SMALL ANIMAL C. Signs: Typically urinary incontinence since birth. E. Silicates Must be differentiated from behavioral problems. 1. German shepherds are predisposed Most commonly unilaterally affected; conse- 2. Typically do not dissolve quently, many affected dogs can store and void F. Uroliths within the urinary bladder urine normally as well 1. Retrieved by ventral cystotomy D. Can be intramural or extramural 2. Always flush urethra to assure none are lodged E. Diagnosis: Ultrasound may reveal a dilated renal there intraoperatively pelvis and hydroureter, which are commonly 3. Close in 1, 2, or 3 layers using appositional or seen concurrently with this disease. Excretory inverting suture patterns urography is useful in identifying the disease and a. Use a monofilament absorbable suture the location of the ectopia material F. Treatment: Surgical disease, typically in attempt b. Chromic catgut would not be appropriate to create new opening of the ureter into the G. Urethral stones urinary bladder and resect any abnormal tissue. 1. Typically male dogs; stones lodge at the Ureteronephrectomy should be reserved for only base of the os penis, dorsal to the ischium cases in which renal function of that collecting or within the prostatic urethra most commonly unit cannot be saved 2. Can present with urinary obstruction and be G. Prognosis: Guarded; a substantial proportion an emergency of treated dogs will have some persistence of a. Hyperkalemia: Most effective treatment is to urinary incontinence. This is ascribed to an reestablish urinary flow. Can also use insu- underlying problem with the urethral sphincter lin and glucose, calcium gluconate, and so- mechanism and is called urethral sphincter dium bicarbonate to decrease potassium in mechanism incontinence an emergency III. Uroliths: The vast majority of urinary calculi occur in 3. Performing a cystotomy is preferable to a ure- the lower urinary tract in dogs and cats throtomy, so attempt to flush the stones back A. Struvite (triple phosphate) into the bladder if possible 1. Radiopaque stone 4. If cannot get stones back into the urinary 2. Most common stone in dogs; formerly was bladder (rare), then perform urethrotomy or the most common stone in cats but has been urethrostomy surpassed by calcium oxylate more recently a. Dogs: Scrotal urethrostomy is preferred 3. Can be associated with urease-producing location but can also perform a prescrotal, bacteria, so always rule out concurrent urinary perineal (difficult in a dog), or prepubic tract infection procedure 4. Can dissolve with special diet to lower urinary b. Cats: Perineal or prepubic urethrostomy pH and antibiotics (if appropriate) but takes IV. Bladder neoplasia considerable time A. Most common tumor of the bladder is transitional 5. Surgical removal of the uroliths is also an cell carcinoma appropriate treatment, particularly in patients 1. Scottish terriers are over-represented with clinical signs associated with the uroliths. 2. Canines: Females more commonly affected B. Calcium oxalate than males 1. Radiopaque stone 3. In dogs, location is often associated with the 2. Recently identified as most common stone trigone, often making surgical resection of urinary tract in cats difficult. In cats, can be apical and lend itself 3. Can be associated with concurrent to surgical resection hypercalcemia 4. Possible link to exposure to chemicals. Also, 4. Some breeds predisposed (e.g., miniature linked with exposure to acrolein, which is a schnauzers, poodles) metabolite of cyclophosphamide 5. Will not dissolve 5. Diagnosis: Contrast radiographs, abdominal C. Cystine ultrasound can each delineate a mass in the 1. Radiolucent stone typically bladder. Cytologic determination can be made 2. Inborn error in metabolism, most commonly from sediment from an acquired urine sample. seen in dachshunds and English bulldogs In general, it is recommended that a traumatic 3. Can be dissolved using catheterization is performed to obtain a 2-mercaptopropionylglycine as sample. Cystocentesis is typically avoided well as a low-protein and alkalizing diet due to concerns over potentially seeding the D. Urate neoplasia else where. Abdominal ultrasound 1. Radiolucent stone typically is useful for staging for metastatic disease 2. Can be associated with portosystemic shunts as well. Can also metastasize to bone and 3. Metabolic problem in liver and kidney lung, so chest radiographs are also tissues in some dogs, especially the recommended Dalmatian 6. Treatment: Can attempt surgical resection if it 4. Can try to prevent with low-protein, alkalizing is located in an anatomic region that is amena- diet and allopurinol ble to surgical resection. Typically, therapy is  CHAPTER 27 Soft Tissue Surgery 381 centered on piroxicam, which is a nonsteroidal alopecia, gynecomastia, swollen prepuce, antiinflammatory medication. Other medica- myelotoxicosis, male dog attraction, penile tions used include cisplatin, carboplatin, atrophy, and squatting posture during mitoxantrone urination 7. Prognosis: Typically guarded to poor as often a. Diagnosis: Testicular mass or signs of metastatic at the time of diagnosis hyperestrogenism b. Treatment: Castration c. Prognosis: Favorable; does metastasize SURGICAL DISEASES more than other testicular tumors, but OF THE GENITAL TRACT metastatic disease is still rare I. Intersex malformations 2. Interstitial (Leydig) cell tumor: Secrete testos- A. Hermaphrodite: Possess both male and female terone so may predispose to benign prostatic gonadal tissue hyperplasia, perianal adenoma, or perineal B. Pseudohermaphrodite: Possess only one gonadal hernias. Typically small and benign tumors. tissue, but external genitalia has some character- Treatment via castration yields an excellent istics of the opposite sex prognosis II. Diseases of the male genital tract 3. Seminoma: Benign growth of germinal epithe- A. Prostatic neoplasia lium. Castration gives excellent prognosis 1. Most commonly adenocarcinoma or transitional F. Phimosis: Inability of the penis to protrude from cell carcinoma the preputial orifice 2. Incidence of prostatic neoplasia is not affected G. Paraphimosis: Inability of the penis to retract by castration back within the prepuce 3. Treatment: Can attempt a prostatectomy, but III. Diseases of the female genital tract urinary incontinence is reported to be a serious A. Ovarian remnant side effect. Prognosis is poor 1. Can occur after ovariohysterectomy B. Benign prostatic hyperplasia 2. Signs of estrus behavior post spaying 1. Occurs due to androgenic stimulation under 3. Diagnosis: Clinical signs; can run estrogen and control of the testicles progesterone assays; abdominal ultrasound 2. Prostate enlarged and may interfere with may also show cystic ovarian remnant urination or defecation 4. Treatment: Excise remnant tissue 3. Rectal examination reveals a large, firm 5. Prognosis: Excellent if all tissue removed prostate that is typically nonpainful and B. Ovarian tumors are rare, owing to the common symmetrical procedure of performing ovariohysterectomy 4. Treatment: Castration is the most effective early in life treatment. Can attempt estrogen therapy in C. Cystic endometrial hyperplasia or pyometra cases where owners will not castrate complex C. Prostatic abscesses 1. Develops during diestrus: Corpora lutea forms 1. Serious medical disease and secretes progesterone. This progesterone 2. Diagnosis: Enlarged and painful prostate, typi- increases uterine glandular secretions and cally asymmetrical decreases myometrial contractions 3. Treatment: Stabilization and surgical explora- 2. Clinical signs can include discharge through tion. Lance abscess and omentalize. Place the vulva, lethargy, vomiting, anorexia, drains or marsupialize the abscess polyurina or polydipsia resulting from 4. Prognosis: Guarded, 25% perioperative endotoxemia, signs of sepsis, or abdominal mortality rate distension. Escherichia coli is most commonly D. Cryptorchidism the causative organism 1. Diagnosis: History if owner has possessed the 3. Classically two types: Open vs. closed. In the dog or cat since a young age and has complete open type, the cervix is open, allowing drain- medical and surgical history of the animal. If age to occur. In the closed type, the cervix is not, can conduct hormonal assays to detect closed, and drainage is not occurring. androgen levels suggestive of the presence of Typically, closed pyometra is a more serious testicular tissue. In cats, can simply examine disease than open pyometra, but both are the penis for spikes on the base of penis, serious which would indicate retained testicular tissue 4. Diagnosis: Typically clinical diagnosis. Survey 2. Medical importance: Potentially unwanted radiographs reveal a fluid opacity between breedings as well as significantly increased the bladder and colon that can displace a incidence of testicular neoplasia in cryptorchid considerable amount of tissues within the testes compared with scrotal testes abdomen. CBC typically shows a leukocytosis 3. Locate testicle and remove with a left shift, but not always. Can be febrile, E. Testicular tumors hypothermic, or normothermic. Serum chemis- 1. Sertoli cell tumor: Secrete estrogens and try panel may show azotemia from endotoxic can have signs of hyperestrogenism, renal damage or dehydration. Vaginal cytology which include bilaterally symmetrical reveals septic purulent exudate 382 SECTION II SMALL ANIMAL 5. Treatment: Ovariohysterectomy is the treat- b. Can alternately or concurrently exit through ment of choice. Always immediately on stabili- the tympanic membrane and enter the zation in a closed pyometra, timing of surgery external ear canal, causing signs of otitis is debated in open pyometra. If owners want to externa or aural irritation and discharge breed, can attempt to lyse corpora lutea via 2. Most commonly occur in young cats. Abyssinian prostaglandin F-2 and antibiotics, but eventual cats are overrepresented. Potentially a history recurrence is very common with this therapy of chronic upper respiratory infections before D. Cesarean section the polyp appears 1. Indicated in situations of dystocia, including 3. Diagnosis: High index of suspicion based no birth despite strong contractions for longer on clinical signs and patient signalment. than 30 minutes, weaker straining for longer Radiographs may reveal material within the than 2 hours, no birth for more than 4 hours, tympanic bulla(e) unilaterally or bilaterally. retained baby lodged in vulva, any signs of Otoscopic examination or nasopharyngeal toxicity, or signs of fetal distress (e.g. decreased examination may reveal a polyp heart rate, decreased motion) 4. Treatment: Removal of the polyp via a ventral 2. Surgical emergency: Traditional approach, then bulla osteotomy is very effective in curing this hysterotomy to access puppies or kittens disease with a less than 2% recurrence rate. An 3. Can be due to maternal factors such as uterine alternative therapy involves manual traction of inertia, abnormal vaginal conformation, de- the polyp to remove it; recurrence rates are creased pelvic canal size. Can also be due to higher with this therapy but decrease to ap- fetal factors such as large head confirmation proximately 25% when prednisone therapy (especially brachycephalic breeds), fetal is added monsters, fetal malposition. It is normal and 5. Prognosis: Excellent acceptable for puppies and kittens to be born C. Laryngeal paralysis in the breech position 1. More common in dogs than in cats. Two forms: 4. More common in small and brachycephalic Somewhat rare congenital form, which has been breeds described in breeds including the Siberian husky, Bouvier des Flanders, dalmatian, bull ter- rier, and rottweiler. The acquired form is much SURGICAL DISEASES more common and typically affects large-breed OF THE RESPIRATORY TRACT middle-aged to older dogs. Labrador retrievers I. Diseases of the upper respiratory tract are overrepresented. Underlying cause of laryn- A. Brachycephalic airway syndrome geal paralysis is dysfunction of the recurrent 1. Seen in brachycephalic breeds as a result of laryngeal nerve. Almost routinely bilateral in conformational anatomy of head and nose dogs with clinical signs 2. Components include stenotic nares, elongated 2. Clinical signs: Inspiratory stridor, change in soft palate, everted laryngeal saccules, and in phonation, coughing, exercise intolerance, some dogs can lead to laryngeal collapse. collapse, cyanosis. Can be linked with other English bulldogs can also concurrently have a diseases, including myasthenia gravis, poly- congenitally hypoplastic trachea, exacerbat- neuropathy, polymyopathy, neoplasia in the ing their disease mediastinum or neck, trauma, or hypothyroid- 3. Signs attributable to progressive inspiratory ism. Can be in severe compromise when dyspnea, decreased tolerance to exercise; can present, in which case oxygen supplementa- collapse tion, IV access, active cooling, sedatives, and 4. Diagnosis: Often a clinical diagnosis. Chest possibly steroids are helpful radiographs should be obtained to examine for 3. Diagnosis: Requires heavy sedation or light noncardiogenic pulmonary edema, cor pulmo- anesthesia to confirm diagnosis.