Author

Stephen J. Birchard DVM, MS, Diplomate ACVS

Tuesday, September 19, 2017

Should We Spay Dogs When Removing Mammary Tumors? This study answers that question.

V.M. Kristiansen, A. NĂždtvedt, A.M. Breen, et. al. Effect of ovariohysterectomy at the time of tumor removal in dogs with benign mammary tumors and hyperplastic lesions: A randomized controlled clinical trial 
J Vet Intern Med 2013;27:935–942 

Summary

The authors of this study sought to answer the following question: is there a clinical benefit to performing ovariohysterectomy (OHE) at the time of benign mammary tumor removal in dogs.  Their hypothesis was that removal of ovarian hormones by OHE would decrease the development of new benign mammary tumors and thus would have important clinical ramifications. In a randomized, controlled clinical trial, dogs having surgery to remove benign mammary tumors were placed in one of 2 groups: those also having OHE performed at the time of tumor removal (n=42), and those not having OHE performed (n=42). All tumors were analyzed by histopathology. The dogs were followed for at least 80 months and long term follow-up information obtained either by phone calls to owners or by recheck examinations by veterinarians. 

New benign mammary tumors developed in 64% of in tact dogs compared to 36% of dogs having OHE. This was statistically significant and showed the clinical benefit of concomitant OHE with benign mammary tumor removal. Nine of the intact dogs also went on to develop disorders of the ovaries or uterus, such as pyometra. There was no difference in survival data between the 2 groups. 

Commentary

For years surgeons have recommended OHE in combination with removal of mammary tumors, not because of any proven benefit related to the mammary neoplasia, but to prevent other disorders such as pyometra. This study provides evidence of the benefit of performing OHE in combination with mammary tumor removal. The authors make the case that since dogs that develop benign mammary tumors are also at increased risk of developing malignant mammary tumors, prevention of future malignant tumors may also be a positive factor of OHE.

The lack of difference in survival between the two groups may be misleading since some of the dogs were euthanized. The many and varied issues surrounding the owner’s decision to euthanize make the survival data, in the author’s words, a “soft and biased endpoint in the study.” In contrast, the different rates of tumor recurrence between the 2 groups is objective data in which statistical significance was found.

Conclusions

This prospective randomized study provides objective evidence of the benefit of OHE in dogs being surgically treated for mammary tumors. Clinicians can recommend OHE at the time of mammary tumor removal as evidence based medicine approach to treatment, not just in the prevention of reproductive disorders such as pyometra and ovarian tumors, but in prevention of benign mammary tumors.

Monday, July 3, 2017

Surgical Removal of Screw Tail in Bulldogs

Case Report
Tank is a 7 year old male castrated English bulldog that presented for chronic skin fold dermatitis secondary to screw tail conformation.(Fig.1) 
Fig. 1: Tank, a 7 year old male castrated English Bulldog
The dog was showing signs of pruritis and pain in the tail area for several months. Physical examination revealed patchy partial alopecia of the lateral trunk and evidence of pyoderma in the skin folds associated with an ingrown tail.(Fig.2)
Fig. 2: The tail on Tank showing the typical screw  tail conformation
Preoperative thoracic radiographs showed no significant abnormalities. A radiograph of the caudal spine showed a typical abnormal tail anatomy common in bulldogs.
(Fig. 3) 
Fig. 3: Lateral radiograph of the caudal vertebrae on Tank showing the
abnormal coccygeal vertebrae. (arrow)
Pre-anesthetic CBC and serum chemistry profile on Tank were within normal limits. 

Surgical Procedure
Under general anesthesia, Tank was placed in sternal recumbency and the tail and adjacent skin was clipped and prepared for aseptic surgery. The anal sacs were expressed and a purse string suture was placed in the anus to prevent fecal contamination of the surgical site. Intravenous cephazolin was administered as a prophylactic antibiotic. 

The surgery was begun by making a cranial to caudal incision dorsally over the base of the tail.(Fig. 4) 
Fig. 4: The caudectomy on Tank began with an incision over the  dorsal aspect of the tail.
The tissues were dissected down to the bone by blunt and sharp dissection. After the soft tissues were dissected off, the coccygeal vertebrae were severed with a bone cutter and rongeurs.(Fig. 5)
Fig. 5: Appearance of surgical site after severing the coccygeal vertebrae. Arrow
indicates the cut edge of the vertebrae on the portion of tail to be removed.
The tail was then removed by extending the skin incisions ventrally on each side until the tail was no longer attached to the body.(Fig. 6)
Fig. 6: Surgical site after complete removal of the tail. Note the  cut
edge of the coccygeal vertebrae on the body (white arrow), and cut
edge of the coccygeal vertebrae on the excised tail (black arrow).
Care was taken not to injure the rectum which is just ventral to the tail. A Jackson-Pratt closed suction drain was placed in the deep aspect of the incision prior to closure. For more information on Jackson Pratt drains see: https://drstephenbirchard.blogspot.com/2014/03/jackson-pratt-drains-for-wounds-in-dog.html Excess skin was removed, and the surgical wound was closed in several layers: deep tissues with 2-0 PDS simple interrupted, subcutaneous tissues with 3-0 Monocryl simple interrupted, and the skin with 3-0 Monocryl simple interrupted. The purse string suture was removed. (Fig. 7)
Completed caudectomy on Tank including placement of the Jackson-Pratt drain.
Postoperatively Tank was given supportive care consisting of intravenous fluids, analgesic therapy, incision care and drain maintenance. Tank was discharged from the hospital the following day. Tank’s drain was removed 3 days postoperatively, and examination by the referring veterinarian 10 days postoperatively found satisfactory healing of the incision and improvement of his clinical signs. A follow-up phone call to the owner 1 month after surgery found Tank to continue doing well with no further pruritis or evidence of infection in the tail area.

Discussion
Intertriginous dermatoses, or skin fold pyoderma, is a well recognized disorder caused by excessive skin folds in various regions in dogs, such as nasal, lip, perivulvular, and the secondary to the screw-tail, or ingrown tail abnormality in bulldogs. Redundant skin in these areas leads to skin friction, excessive moisture, and poor air circulation. Trapped skin secretions are fertile ground for surface bacteria and yeast to establish infection. 

Medical treatment consisting of hair clipping, medicated soaps and shampoos, and topical and systemic antibiotics may improve the condition, but surgical resection of the excessive skin is necessary to achieve successful long-term resolution. In bulldogs with ingrown tail, amputation of the tail is the most effective method of treating this form of intertriginous dermatoses. However, detailed descriptions of the technique for removal of the very abnormal bulldog tail are not widely available in the veterinary literature. 

Postoperative complications after caudectomy for ingrown tail were analyzed in one clinical study of 17 dogs. (1) Short-term complications were rare but included postoperative wound infection and changes in defecation behavior. Long-term complications were not seen and the authors stated that the procedure effectively resolved clinical signs in the dogs studied. 

References
1. Knight SM1, Radlinsky MG, Cornell KK, Schmiedt CW. Postoperative complications associated with caudectomy in brachycephalic dogs with ingrown tails. J Am Anim Hosp Assoc. 2013 Jul-Aug;49(4):237-42. 

Wednesday, April 12, 2017

Acute Traumatic Abdominal Hernia in Dogs and Cats: Key Point: Always do a complete abdominal exploratory!

Case Report

Cass is a 2 year old spayed female who presented to the emergency service after been bitten by another dog. She had no pertinent history of other health problems. On physical examination Cass had a palpable soft tissue subcutaneous swelling on the left lateral abdomen. A defect in the abdominal wall was palpable deep to the swelling and viscera were thought to be in the subcutaneous space. 

Plain radiographs of the abdomen confirmed a left lateral abdominal hernia. (Fig. 1) No other radiographic abnormalities were found. 
Fig. 1; Ventrodorsal radiograph of Cass showing the hernia of the left lateral abdomen (arrows).
Cass was initially treated with supportive care consisting of intravenous fluids with a balanced electrolyte solution, analgesics, and antibiotics. Preoperative CBC and serum chemistry profile were within normal limits. Cass was placed under general anesthesia and the ventral abdomen was clipped and prepared for aseptic surgery. (Fig. 2) 
Fig. 2: Cass in dorsal recumbency after clipping and prepping for  abdominal surgery.
Note the bulge on the left lateral abdomen at the site of the hernia.
A ventral midline abdominal approach was made. On thorough exploratory of all abdominal structures herniation of a portion of jejunum was found in a left sided abdominal wall defect.(Fig. 3, 4) 
Fig. 3: Intraoperative view of the abdominal cavity on Cass. (Head is to the left.)
Note herniated bowel and omentum (arrow).
Fig. 4: Same intraoperative view as figure 3 after reduction of the hernia showing the muscular defect.
Gentle traction on the herniated bowel reduced the hernia and the bowel mesentery was bruised but all tissues were viable. The abdominal muscle defect was closed from within the abdominal cavity with 2-0 PDS simple continuous pattern.(Fig. 5) 
Fig. 5: Same intraoperative view as figures 3 and 4 showing closure of the hernia.
The ventral abdominal incision was closed routinely. 

Postoperatively supportive care (IV fluids, analgesics, and antibiotics) was continued. Cass made an uneventful recovery and was discharged the day after surgery. At suture removal 10 days postoperatively Cass was doing well.

Discussion

In animals with severe abdominal trauma, hernias can be missed on initial physical examination. Serial, thorough physical examinations and careful analysis of abdominal imaging is recommended to fully assess trauma patients. Intestine and omentum were the 2 most commonly herniated structures in the study previously mentioned. (1)

Bite wounds were the most common cause of traumatic abdominal hernias in one study, with vehicular trauma being the next most common cause. (1) This is in contrast to an older study that found blunt trauma to be the primary cause of traumatic hernias.(2) Additional injuries, such as bowel perforation, are common complications of abdominal hernias. 

Key Point: Dogs and cats with acute traumatic abdominal hernias should have a complete abdominal exploratory via routine ventral approach. The hernias can be repaired from within the peritoneal cavity by closing the affected interior muscle layers. (3)


References
1. Shaw, Scott P; Rozanski, Elizabeth A; Rush, John E. Traumatic body wall herniation in 36 dogs and cats. JAAHA 39:35-45 2003.
2. Waldron DR, Hedlung CS, Pechman R. Abdominal hernias in dogs and cats: a review of 24 cases. JAAHA, 22:817-822,1986 
3. Smeak, DD. Abdominal wall reconstruction and hernias. In: Veterinary Surgery Small Animal, eds. Tobias KM, Johnston, SA. Elsevier, St. Louis, pg. 1368.

Friday, January 27, 2017

When Is Umbilical Hernia in Dogs An Emergency Operation? Here's a Great Example

Case Report

A 7-year-old spayed female mixed breed dog named Lola presented with acute vomiting and rapid enlargement of a mass over her umbilicus.(Fig.1) 
Fig. 1: Lola, a 7 year old female spayed dog
The owners reported that she had a hernia there since birth but it just recently got much larger. The mass was soft, painful on palpation, and not reducible. An umbilical hernia containing abdominal viscera was suspected.

Plain film abdominal radiographs were obtained and confirmed an umbilical hernia with loops of intestine in the hernia sac. (Fig.2)  The remainder of the abdomen was radiographically within normal limits. 
Fig. 2: Lateral abdominal radiograph in Lola showing
an umbilical hernia with incarcerated bowel (arrow)
Complete blood count and serum chemistry profile were unremarkable. An intravenous catheter was placed and a balanced electrolyte solution administered to correct dehydration. Under general anesthesia the ventral abdomen was clipped and prepared for aseptic surgery. (Fig.3) 
Fig. 3: Appearance of the hernia in Lola after clipping for surgical repair
A ventral abdominal approach was performed with care taken to not injure structures within the hernia. A strangulated loop of jejunum was found in the hernia. (Fig.4) The remainder of the abdomen was normal. 
Fig. 4: Intraoperative photo of Lola during abdominal exploratory showing the
strangulated portion of jejunum after it was reduced.
The affected segment of intestine was resected and an end to end anastomosis performed (see http://drstephenbirchard.blogspot.com/2013/10/intestinal-anastomosis-made-simple.html for details on technique for intestinal anastomosis).  Debridement of the tissue edges of the hernia was not necessary and it was repaired as part of the routine linea alba closure with 2-0 PDS, simple continuous pattern. The remainder of the abdominal incision was closed routinely. Postoperative abdominal radiographs confirmed satisfactory closure of the hernia. (Fig. 5) 
Fig. 5: Lateral abdominal radiograph of Lola 1 day after repair of the umbilical hernia.
Lola recovered well from surgery and was released from the hospital 2 days postoperatively.

Discussion

Lola is an example of a dog with an incarcerated (non-reducible), and strangulated (loss of blood supply of the hernia contents) umbilical hernia. Umbilical hernias are common in dogs and cats but rarely do they contain intestine or other abdominal organs.(1) More commonly umbilical hernias are small and contain a portion of the falciform ligament or greater omentum. 

Plain film radiographs were diagnostic for the hernia in Lola. Ultrasonography can also be useful to determine if a hernia is present and if organs are located in the hernia sac. 

The clinical signs of acute vomiting and pain on palpation were suggestive of intestinal obstruction, and possibly strangulation. Vomiting was predictive of non-viable intestine in inguinal hernias in dogs in one study.(2) Emergency surgery is indicated when this type of hernia is suspected. 

In Lola the hernia repair was straightforward since adequate local tissues, i.e. rectus muscle fascia, was available for closure without tension across the suture line. Larger defects may require a muscle flap or mesh implant, such as polypropylene mesh, for effective repair. Mesh is well tolerated in dogs and provides a strong and stable closure for abdominal wall defects with minimal complications.(3)

Complications of hernia repair include pain, seroma, infection, reoccurrence and mesh rejection requiring removal.   However, complications are rare and the prognosis for successful repair of congenital and traumatic hernias is generally good. 

This is the first in a series of Veterinary Key Points blogs addressing congenital and acquired hernias in dogs and cats. Watch for future articles on other hernia types and their treatment.

References

1. Ruble RP, Hird DW. Congenital abnormalities in immature dogs from a pet store: 253 cases (1987-1988). J Am Vet Med Assoc. 202(4) 633-636, 1993

2. Water DJ, Roy RG , Stone EA. A retrospective study of inguinal hernia in 35 dogs. Vet Surg 22:44, 1993

3. Bowman K, Birchard SJ, Bright RM. Complications associated with implantation of polypropylene mesh in dogs and cats: A retrospective study of 21 cases (1984-1996). J Am An Hosp Assoc 34:225-233, 1998