degu

Two Techniquesfor Neutering a DeguVittorio Capello, DVM and Jan Gisle Sjøberg, DVM

CLINICIAN’SN O T E B O O K

www.exoticdvm.com EXOTIC VOLUME 6.6D V M 27

Bilateral orchiectomy from an abdomi-nal approach is feasible in all smallmammal species having an openvaginal process (inguinal canal). Thistechnique also has been described inrabbits.

For better comprehension of theproper techniques for neuteringrodents, it may be useful to reviewsome anatomical features. Because theinguinal canal of lagomorphs androdents remains open throughout life,there is not a true scrotum, but rathertwo separate hemiscrotal sacs. Inlagomorphs, they are positionedcranial to the penis; in rodent species,they are caudal to the penis, as theyare in other species of placentalmammals (except rabbits). The term“canal” is not appropriate for rodents,because it is so wide.

Hemiscrotal sacs have anatomicpeculiarities among different groupsof rodents. Rat-like rodents (rat,mouse, hamster, gerbil) have well-developed hemiscrotal sacs. The mostcommon technique for castration inthese species is scrotal or prescrotalaccess, both with an open (uncovered)or closed (covered) technique.Porcupine-like rodents (guinea pig,chinchilla, degu) have less developedhemiscrotal sacs, which are moresimilar to “diverticula” of the abdomi-nal cavity, but the technique for

castration is similar to that of rat-likerodents (see Exotic DVM 6[5]:27-30 fora scrotal technique for neuteringchinchillas). Squirrel-like rodents donot have well-developed hemiscrotalsacs because the testicles are locatedcaudally in the inguinal canal or in theabdomen, depending on the season.They could be defined as “functionalcryptorchids.”

On the basis of these features,castration in prairie dogs (usuallydone when they are young) is easierwhen performed with the abdominalapproach, because it is easier to locatethe testicles (see Exotic DVM 2[5]:19-23, 2000). In adult prairie dogs, theprescrotal technique is possible,because under anesthesia it is easy topush the testicles caudally.

Being a porcupine-like rodent,degus are different from prairie dogs.The scrotal or prescrotal technique isfeasible and recommended. It isaccurate to compare this species to agerbil, which is a rat-like rodent.

In all rodent species, it is recom-mended or mandatory to performligation of the vaginal process(inguinal canal) to prevent herniationof fat, seminal vesicles, urinarybladder or bowel. This is moredifficult in squirrel-like rodents, sincethe hemiscrotal sacs are not welldeveloped.

Vittorio Capello, DVMClinica Veterinaria S. SiroClinica Veterinaria Gran SassoMilano, [email protected]

Jan Gisle Sjoberg, DVMProVetHøvik, [email protected]

EXOTIC VOLUME 6.6D V M28


4 Subcutaneous tissue is bluntly dissectedto expose the vaginal process. The vaginal

process is very large in porcupine-like rodents. 3 The surgical area is isolated with a self-

adhesive transparent drape. The prescrotalskin is incised 2-3 mm lateral to the prepuce.

6 Using absorbable suture (Monocryl 4-0), a knot is placed around the vaginal process

but is not tightened. After the testicle isremoved, this knot will be used to ligate thevaginal process.

5 The vaginal process is bluntly isolated. 7 The vaginal process is incised, and thetesticle (A) is exposed up to the tail of the

epidydimis (B). During this procedure, thehemiscrotal sac (C) is everted.

1 The degu is anesthetized using a combination of ketamine (20 mg/kg) and

medetomidine (70 µg/kg) both injectedintramuscularly. Butorphanol (0.3 mg/kg) isadministered subcutaneously. Generalanesthesia is maintained with isoflurane (1.5%)and oxygen delivered by facemask. The degu isplaced in dorsal recumbency, and the periscro-tal region is widely shaved.

2 The area is scrubbed and asepticallyprepared using povidone iodine diluted

1:10 with sterile water or saline. Otherwise,0.1% chlorhexidine solution may be used.

Prescrotal Open Technique for Neutering DegusVittorio Capello, DVM

Two Techniques for Neutering a DeguV. Capello and J.G. Sjøberg

www.exoticdvm.com EXOTIC VOLUME 6.6D V M 29

8 The tail of the epididymis is dissectedfrom the base of the everted hemiscrotal

sac.9 The everted hemiscrotal sac is replaced in

the normal position using the tip of theforceps.

13Subcutaneous tissues are sutured in acontinuous pattern using 4-0

Monocryl.

14The intradermal layer is sutured in acontinuous pattern. 15A small film of tissue glue is applied to

the incision line. 16The procedure is repeated on theother side through another para-

preputial skin incision. Shown is the appear-ance of the two skin suture lines.

10The spermatic cord is double clampedand transected, removing the testicle.

11The spermatic cord is ligated using 4-0 Monocryl. Alternatively, the

spermatic cord can be ligated prior totransection.

12The knot previously placed around thevaginal process is tightened. Ligation

of the vaginal process is easier when per-formed as far proximally as possible and ismore effective at that site in closing theabdominal cavity. This step is very important inpreventing herniation of tissues. Herniation isnot a common complication if a large portionof the abundant fat pad surrounding thetesticle is left in place.

EXOTIC VOLUME 6.6D V M30


1 The degu is positioned in a dorsal recumbency and the surgical field is

aseptically prepared. 2 The scrotum is incised an appropriate

length over the testicle, and the tunica isgrasped with forceps and extracted from theincision.

3 After the surrounding tissues are bluntly separated with cotton-tipped swabs, the

tunica is incised and the testicle is exposedand removed with open technique.

4,5 The vessels and tunica are closed with a single ligation of 1-0 catgut. 7 The procedure is repeated on the oppositeside.

9 The degu recovers from anesthesia.8 The skin is closed with 1-0 catgutinterrupted sutures.

Scrotal Open Technique for Neutering DegusJan Gisle Sjøberg, DVM

degu

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