Notes for Courses
Head
Sialoceles are also termed salivary mucoceles and are collections of saliva within subcutaneous tissue. These saliva-filled cavities are lined by inflammatory connective tissue, with the most common source being leakage from the sublingual salivary gland or duct. Causes include trauma, sialoliths, foreign bodies, and neoplasia; I most frequently see sialoliths as a cause, and even had one case in which the sialolith was the size of my fist. The most common presenting clinical sign is intermandibular or cranioventral cervical swelling, indicating involvement of the sublingual and mandibular salivary gland. Diagnosis is based on clinical signs of a fluid-filled mass containing a viscous, clear or blood-tinged fluid on aspirate. Cytology will often contain nondegenerate nucleated cells and macrophages with foamy cytoplasm.
Two surgical approaches are commonly used. The first, with the patient in lateral recumbency with the affected side up, a dorsoventral or craniocaudal incision over the mandibular salivary gland cranial to the junction of the maxillary vein and linguofacial vein (come together to form the jugular vein). Once the capsule is incised, the gland can be bluntly dissected free from the capsule with caudal traction, and followed cranially to the sublingual gland and the point where the lingual nerve is encountered. The digastricus muscle may be elevated, and the gland mobilized underneath it to increase cranial extraction, or the muscle may be cut.
The ventral approach involves positioning the patient in dorsal recumbency, and an incision is made 4-5 cm caudal to the mandibular ramus on the affected side and extends rostrally and medial to the ramus towards the symphysis. Once the gland is freed of its capsule, it can be pulled rostromedially underneath the digastricus muscle along the medial edge of the ramus. Once reaching the myelohyoideus muscle, you should encounter the lingual nerve, the stopping point.
Incisions are closed in a routine manner. Drain tubes are recommended. The oral cavity should be examined for a ranula. If present, it should be marsupialized by cutting it open and suturing the external mucosa to the inner lining of the sialocele with an absorbable suture. To see a video of how this procedure is performed, please select this link.
An elongated soft palate is usually part of the brachycephalic airway syndrome (BAS). Other components to assess would include stenotic nares, hypoplastic trachea, and redundant pharyngeal tissue. Dogs may develop everted laryngeal saccules, and over time the larynx may collapse. Dogs with elongated soft palates are usually presented for stertorous breathing, respiratory distress, cyanosis, and collapse, which are exacerbated during warmer weather. Dogs may also be presented for gastrointestinal signs such as gastroesophageal reflux. Pulmonary edema, pneumonia, and pulmonic stenosis are also often seen, particularly in Bulldogs.
Patients are placed in ventral recumbency, and the mouth is opened as wide as possible. The jaw can be suspended with gauze or tape placed around the maxillary canine teeth and suspended to two poles on each side of the operative table. Anticholinergics are administered to avoid bradycardia.
Prior to intubating, the oral cavity is examined for other problems. Once intubated and stabilized, the soft palate is to be resected to the caudal border of the palatine tonsils. A stay suture is placed on each side to assist in rostral retraction of the soft palate and to mark the point at which the palate is to be resected. Resection may take place with scissors, in which the everted mucosal edges are closed at the ½ way point prior to proceeding, or resected with a CO2 laser or radiosurgery unit, and closed with a simple continuous absorbable suture, 3-0 or 4-0, though not required with the latter two. Correction of other components of BAS are indicated at this time. To see a video of how this procedure is performed, please select this link.
Total ear canal ablation is indicated in patients with chronic otitis externa that has failed to respond to appropriate medical management. Often, the ear canal has severely calcified or ossified the ear cartilage with severe epithelial hyperplasia extending beyond the pina and vertical ear canal. Many patients requiring TECA also have concurrent otitis media which should be addressed with concurrent bulla osteotomy. Neoplasia of the ear canal is another indication for TECA (41% of feline cases, ceruminous gland adenocarcinoma). Many dogs that undergo TECA also have concurrent skin disease such as atopy or contact allergy dermatitis which should also be addressed.
TECA is performed with the patient in lateral recumbency. Adequate pain control must be instituted prior to the procedure. Judicious use of surgical scrub is encouraged, as MRSA infections cultured in the bulla are fairly common in my surgical practice. Once sterile towels and drapes are placed, a T-shaped incision is made with the horizontal component parallel to the tragus and the vertical component extending just distal to the level of the horizontal canal. Stay as close as possible to the ear canal, exposing the lateral aspect first. The facial nerve is located caudoventral to the opening of the external acoustic meatus, with the nerve often attached to the canal. Major branches of the great auricular artery are located on the medial side. Once you reach the external acoustic meatus, carefully transect the ear canal as close as possible to the opening, avoiding damage to the facial nerve. Culture should be obtained from the inner ear, and the bulla can be opened with a Steinman pin or an appropriate pair of Rogeur’s. A small curette is now used to clean out the bulla, and it should be rinsed thoroughly. Prior to closure, insertion of a drain tube is also appropriate. To see a video of how this procedure is performed, please select this link.
Gastrointestinal/Abdominal
Gastropexy is a surgical procedure to create an adhesion between the stomach wall and the adjacent body wall. It is most often done for the prevention of gastric dilatation and volvulus but has also been used in the treatment of hiatal hernia. A variety of techniques are available, all with similar biomechanical strength results. Interpretation of these numbers is done with caution, as the strength required to prevent development of GDVS is unknown. The key component to a successful gastropexy is incision through the serosal and peritoneal surfaces and into the muscular portion of each anatomic component being joint.
Incisional gastropexy is performed through a laparotomy incision. A 4-5 cm seromuscular incision is made in the gastric antrum parallel to the long axis of the stomach. To avoid penetration of the gastric mucosa, it is recommended to “slip” the mucosa away by pinching it and feeling it slip away from the incision site. A second incision is made through the transverse abdominus in the right ventrolateral body wall caudal to the last rib about 3-4 cm away. The ends of each incision are sutured together such that the stomach is attached to the body wall, then a continuous absorbable suture layer is created suturing each muscular layer together, gastric muscularis to transverse abdominus. The abdomen is closed in a routine fashion. To see a video of how this procedure is performed, please select this link.
Surgery of the small intestine is most often indicated for GI obstruction, neoplasia, trauma, or malposition (herniation). Diagnosis is based on clinical signs, examination, radiographs, ultrasound scans, or endoscopic examination. Hematologic and biochemical profiles should be performed on patients suspected of having systemic disease and appropriate preoperative therapy directed. Hydration status should be appropriately assessed and addressed as needed prior to surgical exploration.
Surgical techniques involving enterotomy and anastomosis are classified as clean-contaminated or contaminated procedures depending on the amount of spillage. Prophylactic antibiotics are indicated in animals with suspected obstructions because of the increased risk of contamination associated with bacterial overgrowth. First-generation cephalosporins should be administered before surgery on the upper and middle small intestine, whereas second-generation cephalosporins should be considered for surgery of the distal small intestine and large intestine.
The intestines of the dog are approximately 5 times the body length with 80% being small intestine. The duodenum is the most fixed portion, and the jejunum is the longest and most mobile section. The layers of the intestinal wall are the mucosa, submucosa, muscularis, and serosa. The submucosal layer is the layer of greatest strength. The serosa is important for forming a quick seal at a site of injury or incision.
Intestinal resection and anastomosis are recommended for ischemic, necrotic, neoplastic, or fungal-infected segments of intestine. Irreducible intussusceptions are also managed by resection and anastomosis.
The abdomen is opened for routine exploratory. Lap sponges are placed on the edges of the body wall, and an appropriate-sized balfour retractor should be inserted (for cats, use Gelpi retractors). The section of intestine to resect is exteriorized, and placed on a moist lap sponge, if possible milk fluid content away from the surgical site. Doyen forceps should be placed across the intestine at a point where the wall appears pink and healthy, with large forceps placed to the inside of the Doyen forceps to keep the content from spilling. The section is removed with scissors or a scalpel cutting transversely across. The section of bowel is removed along with associated mesentery. The two ends are rinsed and brought together, and a 3-0 or 4-0 PDS suture is placed at the mesenteric and anti-mesenteric borders. Excessive tension is not necessary and may cause necrosis or a purse-string effect. A simple continuous pattern is started from one border to the opposite border, in a full-thickness bite, and then tied off.[1] The other side is done in the same fashion. The mesentery should also be closed, then the entire section rinsed thoroughly. I like to wrap omentum around the surgical site prior to placing it back in the abdomen. I place these patients on fluids for 48 hours and offer no food. To see a video of how this procedure is performed, please select this link.
Complete splenectomy is indicated with known cases of neoplasia, splenic torsion (GDVS), trauma, infiltrative disease, and some immune-mediated disease processes. Splenectomy is of little assistance in patients with IgM-mediated hemolytic disorders but may be helpful in those with therapy-resistant IgG-mediated hemolytic anemia.
Historically, splenectomy was performed with an emphasis on preservation of left gastroepiploic and short gastric arteries in an effort to avoid ischemic necrosis of the gastric fundus supplied by these vessels. This was accomplished by individual ligation of each hilar vessel, a very time-consuming process. This was found not to be true, therefore, splenectomy is often performed by double ligation of those vessels and the splenic artery and vein beyond the pancreatic artery. One should consider prophylactic gastropexy for large-breed dogs undergoing splenectomy to prevent future GDVS.
Through a midline incision, the spleen is exteriorized from the abdomen. If it is friable, push down the abdominal wall and allow the spleen to “spill out”. After completion of an exploratory, exteriorize the fundus of the stomach to expose the short gastric vessels tethered to the head of the spleen and isolate them. Using your index finger, isolate the gastrosplenic ligament, then isolate the short gastric vessels then cross clamp and incise them. Tie a ligature around them at the base of your clamp; make sure to “flash” the clamp to allow the ligature to completely tie off the vessels.
Staying distal to the junction of the splenic artery and the left gastroepiploic artery, the final three branches to ligate are the dorsal artery branch, the main splenic artery in the mid-portion of the spleen, and a caudal branch to the tail of the spleen.[2].
Rear
Recessed vulva is treated surgically with vulvoplasty, also termed episioplasty. Abnormalities in vulvar conformation were thought to be a result of ovariohysterectomy that was performed before sexual maturity causing juvenile vulva. It was recently determined that this was probably not the case, and it was more likely due to breed and body height, favoring large breed dogs.
About ½ of dogs presented with clinical signs referable to perivulvar skin fold dermatitis or vaginitis, while others may have clinical signs secondary to urine pooling in the vagina, urinary tract infections, and urinary incontinence. The diagnosis is self-evident, the decision to pursue surgery is based on severity of the problem, and the patient’s response to conservative therapy. Weight loss may be helpful.
The patient is positioned in sternal recumbency with the hind limbs positioned off the padded end of the surgery table. An estimation of the amount of tissue to resect is estimated by pinching the skin between the thumb and forefinger until the dorsal fold is resolved and the vulva is repositioned. Tissue edges are reapposed in a simple interrupted fashion with 3-0 nylon. To see a video of how this procedure is performed, please select this link.
Perineal hernias occur due to weakness and separation of pelvic diaphragm components. Clinically, one sees caudal protrusion of various organs, including the prostate, paraprostatic tissue, bladder, and intestine. The levator ani is the most common muscle atrophied and is usually absent. The most common location is between the levator ani, internal obturator, and external anal sphincter muscles. Perineal hernias occur at a prevalence of about 0.1-0.4%, almost exclusively in older intact males (females have a larger, broader and stronger levator ani), and is more commonly seen in Poodles, Pekingeses, Boston Terriers, Corgis, Boxers, and other short-tailed breeds of dogs (weakness or underdevelopment of the levator ani and coccygeus muscles).
The cause remains unclear and may be multifactorial. Factors may include congenital, rectal abnormalities, hormonal imbalance (relaxin or estrogen), prostatic enlargement, chronic constipation, cystitis, anal sacculitis, and diarrhea. Many male dogs with perineal hernias also have cystic prostatic hypertrophy or other prostatic disease (25-59%) which may cause chronic straining. Tenesmus from prostatic enlargement may apply traction to the nerves of the sacral plexus, which innervate the levator ani and coccygeus muscles. Clinical signs result from accumulation of fecal material in the deviated or dilated rectum or strangulation of herniated organs. The most common clinical signs include unilateral (right greater than left) or bilateral perineal swelling, straining to defecate, and constipation. During rectal examination in patients with perineal hernia, the examiner’s index finger will pass easily into the dilated segment of the rectum.
To repair the hernia, one of several methods are used. The patient should be fasted 24 hours. Under general anesthesia, the patient is placed in sternal recumbency with the hind legs over the edge of the table. The area is prepped, the anal sacs should be expressed, and a purse string suture placed in the anus. The incision begins near the tail base extending just ventral to a point midway between the ischial tuberosity and the pubis, curving slightly outward and directed away from the anus. Once the hernia sac is exposed, it can be opened and drained, then gentle firm pressure is used to reduce the contents. If the bladder is present, do not completely drain it as the weight will help keep it in the abdominal cavity. After the hernia is reduced, it may be oversewn. Next, identify the order of the coccygeus muscle and levator ani muscle or external anal sphincter. When using the external anal sphincter, be careful not to incorporate the anal sacs in the suture pass. Reappose the muscles with simple interrupted sutures of 3-0 absorbable sutures, but do not tie them until all sutures are preplaced.
For additional support and coverage, the internal obturator muscle can be elevated from the caudal aspect of the ischium in a cranial direction up to the edge of the obturator foramen. To provide greater dorsal elevation of the flap, the internal obturator tendon can be transected. Its cut edge is sutured to the coccygeus and external anal sphincter muscles, while the caudomedial border is sutured to the external anal sphincter ventrally. The remaining tissues are closed in routine fashion. To see a video of how this procedure is performed, please select this link.
Anal sacculitis may occur in any animal of any age, breed, or gender. It is most common in small and toy breeds and rare in cats. Many animals have a recent history of diarrhea, soft stools, or estrus. Complaints include tail chasing, malodorous perianal discharge, pain or tenderness, and behavioral changes. Tenesmus, constipation, and sometimes hematochezia occur.
The anal sacs may appear swollen, red, or inflamed. Abscesses may cause them to rupture with a draining lesion at the 4 or 7 o’clock position. Fever sometimes occurs. Digital palpation or expression of the anal sac may expel normal or abnormal secretions, or they may be hardened and impacted. Failure of medical treatment or suspicion of neoplasia are indications for anal sacculectomy. If a draining tract exists, removal should be delayed until inflammation is controlled. Both anal sacs should be removed even if only one is involved. Open techniques result in a greater risk of fecal incontinence and local infection.
The anal sacs should be flushed with 0.5% chlorhexidine prior to surgery. An appropriate-sized balloon-tip catheter (Foley) should be inserted into the anal sac opening and inflated with saline until the lateral extent of the anal sac can be identified. A curvilinear incision is made over the anal sac. Begin dissecting against the anal sac directly, separating the anal sphincter muscle fibers with small iris scissors. Hemorrhage most commonly comes from the cranial aspect of the gland. The gland is dissected to the mucocutaneous opening, where it is ligated with 4-0 monofilament absorbable suture. All subcutaneous tissues should be apposed with 3-0 or 4-0 simple interrupted sutures. The skin closed with 3-0 nylon.
Postoperatively, an e-collar is encouraged, along with cephalexin, sedation, pain control, and anti-inflammatory medications. The client should be made aware that the possibility of fecal incontinence exists but is usually residual and resolves in a few weeks.
Orthopedic
Coxofemoral joint luxation comprises 90% of all joint luxations seen in dogs and cats, with vehicular trauma being responsible for 85% of those. Up to 6% of luxations in dogs can be bilateral, and 9% in cats. In immature animals, fracture of the femoral capital physis occurs more often than luxation. Closed reduction should be attempted within 72 hours in dogs and may be delayed in cats for 4-5 days to assess conservative therapy attempts.
Joints in which closed reduction fails, or the surgeon is unable to reduce and maintain a stable joint, should be approached surgically. The standard craniodorsal approach to the luxated hip joint should provide ample exposure. I have tried many different methods of repair to stabilize the joint but have found the most success with either (1) toggle-rod stabilization (larger/very unstable), or (2) an extra-capsular suture from the greater trochanter to the origin of the rectus femoris muscle (smaller/more stable luxations).
The joint may be approached through a standard craniolateral approach, with a partial tenotomy of the deep gluteal muscle. The acetabulum should be flushed out thoroughly and the head of the femur examined for surface deformities. At this point, reduction of the hip joint should be possible. If not, then proceed to FHNE.
A 1.5-2 mm hole drilled cranial to caudal in the dorsal aspect of the greater trochanter. Large nonabsorbable suture is passed through this hole (2-0 = small, 0 = medium, 1 = large). Using a semicircular needle, one end of the suture is passed through the thick, fibrous tissue at the origin of the rectus femoris muscle cranial to the acetabulum. Two strands are recommended. Each suture is tied in a figure-of-eight manner while an assistant abducts and internally rotates the femur. The wound is flushed and closed in a routine manner. Dogs are restricted to leash walks for 6 weeks. For a video of this procedure may be performed, please select this link.
FHNE is a salvage procedure for hip dysplasia that is intended to eliminate the pain caused by hip joint laxity in the immature dog, pain, osteoarthritis of the hip joint, as a treatment for aseptic necrosis of the femoral head, fractures of the femoral head or neck, coxofemoral luxation, and failed total hip replacement. FHNE can be performed in any size dog but will result in a better outcome if performed in toy- or small-breed dogs less than 20 kg. Attempts to interpose muscle flaps between the acetabulum and the remnant femoral neck have not proven beneficial, but clinical outcome will be enhanced by complete excision of the femoral neck and immediate postoperative rehabilitation programs.
FHNE is best performed with a craniolateral approach to the hip joint. If the head is still in the acetabulum, it can be luxated by making a small incision in the joint capsule, then inserting a Hatt spoon to deliver the femoral head and incise the round ligament of the femur if it is still intact. As the femoral head is exteriorized, the patella should be parallel with the surface of the table with the patient in lateral recumbency. The femoral neck should be osteotomized in a plane perpendicular to the table, starting at the caudal aspect of the intertrochanteric fossa dorsally to just lateral to the lesser trochanter distally. The osteotomy site should be smoothed with a rongeur or bone rasp. Any remaining joint capsule or fascial attachments should be excised from the femoral head. The joint capsule should be closed over the acetabulum. Aggressive analgesic therapy should be pursued postoperatively to enhance physical therapy effectiveness. To see a video of how this procedure is performed, please select this link.
An alternative treatment to patients with severe hip dysplasia to total hip replacement or FHNE is a procedure called capsular denervation[3]. This procedure is also helpful with patients that can no longer tolerate long term use of NSAID-medication. Surgical deperiostation of the craniolateral acetabulum is thought to be presumed mechanism. Over 90% of patients in this study showed an improvement in clinical signs. An incision centered over the acetabulum to the iliac crest with retraction of the middle gluteal muscle with a Hohman retractor allows exposure of the craniolateral acetabulum. The periosteum may be removed from the 12 to 3 o’clock position using a high speed burr, or a sharp, large bone curette. Closure is routine, and patients are restricted to leash walks for 2 weeks until sutures are removed. Results have been excellent, but not found to last longer than about 2 years clinically. To see a video of how this procedure is performed, please select this link.
[1] Weisman et al, JAVMA 1999.
[2] Hosgood et al, ACVS, 1989.
[3] Kinzel et al, VCOT 2002.