Tips for soft-tissue surgeries

Unlike human medicine where surgery is the exclusive domain of the specialist, general practitioners in veterinary medicine are often called upon to perform a wide variety of surgical procedures.

Due to the cost of equipment and the potentially more daunting nature of orthopedic surgery, most non-specialty trained practitioners have become more experienced with soft-tissue surgery. Although soft-tissue surgery may not seem as intimidating as orthopedic surgery, difficulties can be encountered that can complicate even routine procedures. Many procedures can be made easier by having the right instrument or by knowing "tricks" that may not be found in the surgery texts. The following are some of our favorites for a few commonly encountered soft-tissue surgery situations.

Photo 1: Hartman alligator forceps with round cup jaws.

Alligator forceps with round cup jaws

This is a favorite instrument in our practice. We have the Hartman alligator forceps, but there are other very similar models (Photo 1). This instrument can be used for biopsies of the nasal passage and removing or obtaining biopsies of masses in the ear canal. It can also be used for extracting nasopharyngeal polyps in cats. After retracting the soft palate rostrally with a blunt spay hook, the polyp is grasped with the alligator forceps near its base and removed, hopefully in its entirety, with firm steady traction.

We keep our Hartman forceps sterilized in an individual package so that it may be used in aseptic procedures as well.

Cryptorchid castration tips

It may be difficult in the case of unilateral cryptorchid pets to determine which testicle is undescended. Even testicles located external to the inguinal ring can be difficult to identify by palpation alone in cats or heavier dogs. An easy method to determine this at the time of surgery is to remove the scrotal testicle first. With the descended testicle exteriorized, the spermatic cord can be traced to the corresponding inguinal canal (Photo 2). The contralateral inguinal canal can then be explored for the undescended testicle.

Photo 2: Spermatic cord entering the left inguinal canal (black arrow). The body of the penis is immediately to the right of the spermatic cord (white arrow). (Patient is in dorsal recumbency. Cranial is at the top of the image.)

Abdominal cryptorchid

If you do need to explore the abdomen for an undescended testicle, remember to first identify the vas deferens as it joins the proximal urethra. This structure can then be followed to the testicle that is often discovered deep into the urinary bladder. If the vas deferens is traced to the inguinal ring, the testicle has passed into the inguinal canal. Exploration then should be carried out from the external surface of the body wall.

Culturing the urinary tract mucosa or calculi

When performing a cystotomy for cystic calculi or chronic cystitis, before closing the bladder wall, obtain a small piece of mucosa from the edge for culture and sensitivity. Alternatively, if multiple calculi are removed, one of these can be crushed into the culture media. A study by Hamaide, et al, demonstrated that 18.5 percent more cases will have a positive culture result when either the bladder mucosa or urolith are cultured compared to urine alone. In the same study, if the urine cultured positive, the same organism was cultured from the urolith or bladder mucosa. A stone and mucosa can be cultured together to increase the odds of obtaining a positive result. It is especially important to have an accurate culture in cases of chronically treated urinary tract infections where the risk of infection by drug-resistant organisms is high.

Penrose drain placement

Penrose drains can be useful in closing many superficial and deep lacerations and bite wounds. Drains should be placed in all contaminated wounds that have large subcutaneous pockets or when the initial skin defect must be completely closed due to its location. There are many other indications for drain placement as well. Two common mistakes can be made with drain placement (Photo 3).

Photo 3: In the incorrectly placed Penrose drain (left), the drain exits at the dorsal aspect. The exit sites are too small and impinges on the drain. In the correctly placed Penrose drain (right), the drain remains under the skin at the dorsal aspect and has an adequately sized exit site. (Dorsal is at the top of the image.)

• Drain exits at both ends. The drain should not exit at its dorsal (non-dependent) aspect. Rather, the dorsal-most end of the drain should remain under the skin and may be tacked in place with a suture from the skin surface while the ventral-most end exits from a hole created at the ventral aspect of the affected area. Because Penrose drains are passive systems and depend on gravity, the dorsal aspect is not a productive drainage site. In addition, the second opening at the dorsal extent of the wound increases the risk of introducing an infection into the wound. This may be exacerbated at the time of drain removal as there is a tendency to pull the dorsal, contaminated portion of the drain through the wound.

• Exit site is too small or sutured closed. It is important to have an exit site that is large enough to allow adequate drainage. Penrose drains function by fluid running along the exterior surface of the drain. When the drain is tacked with suture, only one edge of the exit incision should be incorporated. Suturing the drain to both sides of the exit site may inadvertently decrease outflow and, thereby, reduce the effectiveness of the drain.

Photo 4: Partial thickness skin sutures. The needle is passed into the dermis at the edge of the incision, and then is directed more deeply into the subcutaneous fat, before penetrating through the full thickness of the skin to emerge approximately 1 cm away from the edge of the incision.

Skin closure with partial thickness sutures

No matter how experienced you may be as a surgeon, many clients will base their assessment of your skills on the appearance of the skin closure (and, in some cases, on the neatness of the hair clip). An effective method of getting well-apposed skin edges is to place partial thickness skin sutures (Photo 4). A cutting needle is introduced full thickness through the skin into the subcutaneous fat approximately 1 cm away from the incision, and then re-entered into the dermis so that it emerges from the cut surface on the dermis at the incision edge. The needle is then introduced into the dermis on the opposite side of the incision, directed deep into the subcutaneous fat, then redirected back through the skin so that it emerges 1 cm away from the incision on the side opposite of the starting point. Remember to allow for swelling of the incision edges when the sutures are tied.

In almost every procedure, there is a trick that will make the procedure easier or more effective. These are just a few of our favorite tips for soft-tissue surgery's more common procedures. We hope that you will find them useful in your practice.

Dr. Thacher, Diplomate of the American College of Veterinary Surgeons, received his DVM from the University of California-Davis in 1980. He then performed an internship in small animal medicine and surgery and a residency in surgery at The Animal Medical Center, where he then worked as a surgeon and went on to chair the surgery department. Thacher remained at AMC until 1993. During his time at AMC, Thacher gave numerous presentations on surgery throughout the United States and Europe. After leaving AMC, Dr. Thacher worked as a referral surgeon in Vermont for four years. In 1998, he returned to the New York area where he served as Chief of Staff of Affiliated Animal Health, a consortium of 17 small animal hospitals in the NY/NJ area. In 2001, Dr. Thacher joined the staff of Red Bank Veterinary Hospital where he currently serves as Section Head for the Department of Surgery.

Rebecca M. Stanclift graduated from State University of New York at Geneseo with a Bachelor of Science in 1992. She received her DVM in 2001 from Cornell University and then completed an internship in small animal medicine & surgery at Sonora Veterinary Specialists. She was a clinical instructor of small animal elective surgery at Washington State University before being accepted into an internship in small animal surgery at Affiliated Veterinary Specialists. Dr. Stanclift is currently a second year resident in surgery at Red Bank Veterinary Hospital.