Author

Stephen J. Birchard DVM, MS, Diplomate ACVS

Tuesday, July 29, 2014

Cryptorchidism in Dogs: 5 ways to make surgery easier

1. Determine which testicle is retained
Perform a thorough physical examination.(1) Carefully evaluate the scrotum, prescrotal area, inguinal canals, and abdominal cavity. If only 1 testicle is present in the scrotum, push it dorsally and cranially into the inguinal canal to determine whether it is the right or left testicle. After determining which testicle is retained, carefully palpate the prescrotal area and inguinal canal on the affected side. Palpation of the testicle in the inguinal region may be difficult since it can be confused with inguinal fat or lymph node. Ultrasound examination may be helpful to identify the testicle since it has a characteristic appearance (See recent paper on ultrasonography for retained testicles by Felumlee, Reichle, Hecht, et.al. http://onlinelibrary.wiley.com/.../j.1740-8261.../abstract)
Fig. 1: Ultrasound of a cryptorchid dog with a retained testicle found in the abdomen (arrow)
Also perform abdominal palpation, but unless the retained testicle is severely enlarged it will be difficult to palpate.

2. Begin with an incision over the pre-scrotal or inguinal region
Testicles located just cranial to the scrotum can be removed either by pushing the testicle caudally and exposing it through a standard pre-scrotal midline incision, or by simply incising directly over the testicle. Retained testicles in the inguinal area require incision directly over the inguinal canal. (Fig. 2a)
Fig. 2a: Inguinal incision for removal of right sided retained testicle
(Figs 2a through 2f are from: Birchard SJ, Nappier M. Cryptorchidism.
Compend Contin Educ Vet. 2008 Jun;30(6):325-36; quiz 336-7.)
Meticulous and thorough dissection may be required to expose the testicle. Be careful not to injure the pudendoepigastric artery and vein and its branches. It is possible to confuse the inguinal lymph node with the testicle. However, careful dissection and gross examination of the structure should allow differentiation before proceeding with the excision. Once the testicle and associated structures are exposed, remove them as described for prescrotal or normal testicles.

3. For an abdominal testicle, perform a paramedian approach
If one testicle is retained in the abdominal cavity, the paramedian approach to the abdomen offers the advantages of avoiding dissection around the prepuce, which necessitates ligation of the caudal superficial epigastric artery and vein, and not creating dead space in the subcutaneous tissues adjacent to the prepuce. Although the paramedian approach can allow removal of the testicle through a smaller incision than the ventral midline approach, the surgeon should not compromise the exposure of the intra-abdominal structures. Carefully identify the caudal abdominal structures, and expose and remove the testicle only after verifying that the correct structures have been identified. In one clinical study, the prostate gland was inadvertently removed in 3 dogs when insufficient exposure had been obtained while attempting to remove an abdominal testicle.(2) If additional exposure is needed to identify key structures, enlarge the abdominal incision and use appropriate retractors to find the testicle and surrounding organs.

For the paramedian caudal abdominal approach, place the dog in dorsal recumbency, and prepare the ventral abdomen for aseptic surgery. Depending upon the size of dog, make a 6-10 cm incision in the ventral abdomen, approximately 3-4cm lateral to the prepuce. (Fig. 2a)  Incise the subcutaneous tissue to expose the fascia of the rectus abdominus muscle using a scalpel, make a nick incision in the fascia, and sharply incise the fascia with Mayo scissors (not the muscle). (Fig. 2b) 
Fig. 2b: Sharply incise the rectus abdominus fascia with Mayo scissors
Bluntly separate the fibers of the rectus abdominus muscle, beginning with Mayo scissors, then continuing with the index finger of both hands. (Fig. 2c) 
Fig. 2c: Bluntly separate the muscle fibers of the rectus abdominus with fingers
Sharply incise the peritoneum. (Fig. 2d) 
Fig. 2d: Sharply incise the peritoneum with scissors
Place moistened laparotomy sponges on both sides of the body wall, and place a Balfour retractor or hand held retractors to retract the abdominal wall and expose the viscera.

4. Exteriorize the urinary bladder and palpate the prostate gland
If the retained testicle is not immediately seen in the abdominal cavity after making the paramedian approach, exteriorize the urinary bladder and retract it caudally. Identify the prostate gland, and the vas deferens entering the prostate.
Fig. 2e: Exteriorize the urinary bladder and identify the prostate gland and vas deferens
5. Find the vas deferens and follow it to the testicle
Follow the vas deferens cranially until the testicle is located. (Fig. 2e) Triple ligate the vas deferens and the vessels with absorbable suture, cut between the distal 2 ligatures, and remove the testicle.

Rarely, the abdominal approach and identification of the vas deferens may reveal that the testicle is in the inguinal canal. Remove the testicle as previously described in the inguinal approach.

Close the abdominal incision by first closing the external rectus fascia with absorbable suture (e.g. polydioxanone) in either a simple interrupted or simple continuous pattern.(Fig. 2f) Close the subcutaneous tissue and skin routinely.
Fig. 2f: Close the external rectus fascia, subcutaneous tissue, and skin routinely
Fig. 3: Testicular torsion of an abdominal testicle in a 5 month old Boxer
(same dog as in Figure 1) removed by the paramedian approach. 
References

1. Birchard SJ, Nappier M. Cryptorchidism. Compend Contin Educ Vet. 2008 Jun;30(6):325-36; quiz 336-7.
2. Schulz KS, Waldron DR, Smith MM, et al: Inadvertent prostatectomy as a complication of cryptorchidectomy in four dogs. J Am An Hosp Assoc 32: 211-214, 1996.

Monday, July 14, 2014

Surgical Correction of Enlongated Soft Palate in Dogs: Helping brachycephalics breathe.

The soft palate (SP) in the dog forms the partition between the oral and nasopharynx. The cranial border of the SP is attached to the hard palate, and the caudal border extends to the tip of the epiglottis.  Elongated soft palate is one aspect of brachycephalic syndrome and is common in dogs such as English bulldogs, pugs, and Boston terriers. The soft palate is considered elongated if it extends caudally beyond the articulation with the epiglottis. (Fig. 1) 
Fig. 1: Elongated soft palate in a bulldog. (the dog is in ventral recumbency).
Note the tonsils on each side of the palate.
It causes obstruction of the glottis and stertorous breathing which can be a significant respiratory problem in affected dogs. Concomitant stenotic nares worsen the condition by increasing inspiratory effort and causing further extension of the SP into the airway. (see blog on stenotic nares, May 10, 2014)

After obtaining a thorough history and performing a physical examination, take thoracic radiographs to rule out hypoplastic trachea and complications of upper airway obstruction such as pneumonia or pulmonary edema.

Surgical Procedure

A variety of surgical techniques have been described for correction of elongated SP.  The basic objective of surgery is to remove the portion of SP that is causing airway obstruction.  The amount of tissue to be resected is determined by either measuring the portion of SP that extends beyond the tip of the epiglottis, or by removing the portion of SP that extends beyond the caudal pole of the tonsils. (Fig. 2)  
Fig. 2: Incision line for removal of the excess soft palate.
The line connects the caudal pole of the tonsils.
Resection of too much tissue can result in nasal regurgitation of food and water with resultant aspiration pneumonia.

Since hemorrhage is a potential complication of resection, some authors recommend placing a clamp across the area to be removed, removing tissue using electrocautery, or injecting the tissue with epinephrine.  The author does not recommend these techniques since they encourage tissue edema that can be a life-threatening post-operative complication. Surgical laser and the Ligasure device have also been used for soft palate resection.  An atraumatic “cut and sew” technique described many years ago has been very successful in the author's experience and remains my procedure of choice.(1)

Place the animal in ventral recumbency with the head at the end of the table and the mouth held open with an oral speculum. (Fig. 3)  
Fig. 3: Patient positioning for soft palate surgery
Be sure that the endotracheal tube has a competent cuff that is appropriately inflated to prevent aspiration of blood during the procedure. Administer intravenous dexamethasone (0.1 mg/kg) to help control tissue edema secondary to surgical manipulation. Briefly remove the endotracheal tube to examine the soft palate and compare its length to the epiglottis. Replace the tube and secure it in place. Grasp the middle of the SP with an Allis tissue forceps and place stay sutures (4-0 PDS or Monocryl, taper needle) at the lateral aspects of the SP where the incision will be made. (Fig. 4)  
Fig. 4: Stay sutures have been place at the proposed site of incision (dotted line)
From: Bright RM, Wheaton LG (1983) A modified surgical technique for elongated soft palate.
J Am An Hosp Assoc 19: 288-92
Sharply incise the soft palate with long-handled curved Metzenbaum scissors. (Fig. 5)  
Fig. 5: Angled Metzenbaum scissors (above) are useful for incision of the soft palate.
Conventional scissors are shown below.
Incise half way across the palate; the mucosa of this cut portion is then sutured with the long end of the stay suture in a simple continuous pattern. (Fig. 6) 
Fig. 6: The soft palate has been partially incised and suture closure begun.
From: Bright RM, Wheaton LG (1983) A modified surgical technique for elongated soft palate.
 J Am An Hosp Assoc 19: 288-92
Then incise across the remaining palate and suture the mucosa in a similar fashion. (Fig. 7)
Fig.7: Completed excision and closure of the soft palate.
From: Bright RM, Wheaton LG (1983) A modified surgical technique for elongated soft palate.
J Am An Hosp Assoc 19: 288-92
Hemorrhage is usually not a significant problem once the incisions are closed.  The trachea is gently suctioned if hemorrhage was excessive. To check the soft palate for adequate resection of tissue, briefly remove the endotracheal tube to allow comparing the soft palate length to the epiglottis, then replace the tube for the remainder of the dog's recovery from anesthesia.

Postoperative Care
Post-operatively, leave the endotracheal tube in place as long as possible until the animal is fully awake.  The animal should recover in a cool environment and be observed closely for evidence of airway obstruction due to tissue edema.  Keeping the chin elevated seems to help brachycephalic dogs move air during anesthesia recovery. The intravenous steroids can be repeated if edema is suspected. Tramadol is administered for 5 days for analgesia.

Although most dogs recover without incident after soft palate resection, if complications occur they can be life threatening. Therefore recovery from surgery should be in a hospital that has 24 hour care at least for the first night after the procedure. Results of surgery are usually very good; some inspiratory noise may remain but respiratory function should be improved. One study found a good to excellent outcome in 34 dogs with long-term follow up after surgery for brachycephalic syndrome.(2)

References
1. Bright RM, Wheaton LG. A modified surgical technique for elongated soft palate. J Am An Hosp Assoc. 1983; (19): 288-92.
Riecks TW, Birchard SJ, Stephens JA. J Am Vet Med Assoc. 2007;230(9):1324-8.