Soft tissue surgery of rabbits and rodents

Rodent Pediatrics

This article reviews the development, hand-rearing, feeding, housing, and social behavior of common pet rodent species (rats, mice, hamsters, gerbils, guinea pigs, chinchillas, and degus). In addition, common gastrointestinal, respiratory, cardiovascular, dermatologic, musculoskeletal, neurologic, and ophthalmic disorders in pediatric pet rodents are reviewed. Preventative care and indications for spaying and neutering are discussed.

Cicatrização da musculatura reto-abdominal em coelhos submetidos à laparorrafia com fios de sutura à base de quitosana, categute cromado e poliglactina 910

RESUMO Objetivou-se, com este estudo, avaliar o processo de cicatrização da musculatura reto-abdominal em coelhos submetidos à laparorrafia, utilizando-se o fio de sutura à base de quitosana, comparando-o aos fios de categute cromado e poliglactina 910. Foram utilizados 24 coelhos adultos, divididos aleatoriamente em quatro grupos: quitosana e categute 15 dias (QC-15dias), quitosana e categute 30 dias (QC-30 dias), quitosana e poliglactina 910 15 dias (QP-15 dias) e quitosana e poliglactina 910 30 dias (QP-30 dias). Cada grupo foi composto por seis coelhos, nos quais foram realizadas duas incisões, uma do lado direito e outra do lado esquerdo e, posteriormente, a laparorrafia, com o fio de quitosana de um lado e o categute cromado ou poliglactina 910 do outro. Realizou-se análise clínico-cirúrgica, histológica e avaliação de achados de necropsia, além de testes de citotoxicidade e de mecânica no fio de quitosana. Ele apresentou baixa resistência mecânica e citotóxica. O fio de quitosana não proporcionou uma cicatrização satisfatória em coelhos, pois desencadeou uma resposta inflamatória acentuada.

Unilateral flank ovariohysterectomy in guinea pigs (Cavia porcellus)

AIMS

To describe a simple, minimally invasive method of ovariohysterectomy via a unilateral flank approach in guinea pigs, for use in routine desexing of healthy female guinea pigs or treatment of ovarian cysts.

METHODS

The subjects of this retrospective study were 41 client-owned guinea pigs submitted for routine desexing or treatment of ovarian cysts. They included 16 healthy female guinea pigs aged 8-12 months (Group 1), and 15 females aged from 9 months to 3 years (Group 2), and 10 females aged from 3 to 7 years (Group 3) with different-sized ovarian cysts. Prior to surgery, the animals received clinical examination, blood testing (complete blood count and serum biochemistry profile) and examination of the abdomen using ultrasonography, to assess the condition of the reproductive tract and ensure the guinea pigs were fit for surgery. Ovariohysterectomy was performed via a unilateral flank incision made close to the erector spinae muscle starting approximately 1 cm caudal to the last rib. Both ovaries, uterine horns, and the uterine cervix were localised, ligated, and dissected through this unilateral retroperitoneal incision.

RESULTS

Ovariohysterectomy was successfully completed via a single flank incision in 38/41 (93%) guinea pigs. Three guinea pigs with ovarian cysts from Group 3, which were >6 years old died during surgery due to circulatory and respiratory failure under anaesthesia. In the remaining 38 cases, surgery proceeded without complications. A further two guinea pigs from Group 3 were reluctant to move or eat for the first 3 days after surgery but recovered after provision of supportive care. All 38 animals fully recovered and wound healing was normal.

CONCLUSIONS

This is the first report of ovariohysterectomy via a unilateral flank incision in guinea pigs. This approach is a simple, minimally invasive and safe alternative to the midline or bilateral flank approaches currently used for surgery of the reproductive tract in guinea pigs.

Venous blood gas analytes during isoflurane anesthesia in black-tailed prairie dogs (Cynomys ludovicianus)

OBJECTIVE

To describe changes in venous blood gas analytes during isoflurane anesthesia in black-tailed prairie dogs (Cynomys ludovicianus).

DESIGN

Prospective study.

ANIMALS

16 black-tailed prairie dogs.

PROCEDURES

Black-tailed prairie dogs were placed in an anesthesia chamber for induction of general anesthesia, which was maintained with isoflurane in oxygen delivered via mask. Immediately following anesthetic induction, a venous blood sample was obtained from the medial saphenous vein; a second venous blood sample was obtained just prior to anesthetic gas shutoff. An evaluation of venous blood gas analytes was performed on each sample. General linear mixed models with repeated measures were used for data analyses.

RESULTS

Median anesthetic time was 90 minutes (range, 60 to 111 minutes). A significant increase from immediately after induction to completion of anesthesia was observed in Pco2 and mean blood chloride ion, BUN, and creatinine concentrations. A decrease in Po2, mean blood pH, and anion gap was observed from induction of anesthesia to completion. No significant differences during anesthesia were observed in mean base excess or blood bicarbonate, sodium, potassium, calcium, magnesium, blood glucose, lactate, and total CO2 concentrations. No complications occurred during or after anesthesia for any animal.

CONCLUSIONS AND CLINICAL RELEVANCE

Examination of prairie dogs often requires general anesthesia, with isoflurane currently the inhalation agent of choice. Results suggested respiratory acidosis and relative azotemia may occur during isoflurane anesthesia of prairie dogs. Given the increased risk associated with anesthesia in small mammals and the propensity for respiratory disease in prairie dogs, insight into physiologic changes associated with isoflurane anesthesia in healthy prairie dogs can aid in perioperative evaluation and anesthetic monitoring in this rodent species.

Rabbit Soft Tissue Surgery

This article summarizes the available information on different soft tissue surgical procedures in rabbits, based on the literature and the authors' experiences, emphasizing the differences between rabbits and the more familiar dogs and cats. The major surgical principles in rabbits are discussed, and common surgical procedures, such as abdominal exploration, gastrotomy, enterotomy, liver lobectomy, nephrectomy, cystotomy, cystectomy, ovariohysterectomy, ovariectomy, orchidectomy, are described.

Fire ignition during laser surgery in pet rodents

Background

Laser surgery is an attractive alternative to other means of section device in terms of tissue inflammation and interaction, which has been extensively used in human and veterinary medicine. Although accidental ignition during laser surgeries is sporadically reported in human medical literature, to the authors’ knowledge this is the first report regarding laser-dependent fire ignition during surgery in veterinary medicine.

Case presentation

Two rodents, a 13-month old, 27-gram, male pet mouse (Mus musculus) and a 1-year old, female Russian hamster (Phodopus sungorus), underwent surgical removal of masses with diode laser. During the surgical procedures fires ignited from the face masks. The mouse presented severe burns on the head and both forelimbs, it was hospitalized and approximately 2 months after surgery burns were resolved. The hamster presented severe burns on the face and the proximal regions of the body. At 72 hours from the accident the hamster was euthanized.

Conclusion

The present report suggests that fire ignition is a potential life-threatening complication of laser surgery in non-intubated rodents maintained under volatile anesthesia. High oxygen concentrations, the presence of combustible, and the narrowness of the surgical field with the face mask during laser surgery on rodents are risk factors for fire ignition.

Potential behavioural indicators of post-operative pain in male laboratory rabbits following abdominal surgery

This study aimed to identify behaviours that could be used to assess post-operative pain and analgesic efficacy in male rabbits. In consideration of the ‘Three Rs’, behavioural data were collected on seven male New Zealand White rabbits in an ethically approved experiment requiring abdominal implantation of a telemetric device for purposes other than behavioural assessment. Prior to surgery, rabbits were anaesthetised using an isoflurane/oxygen mix and given Carprofen (2 mg kg−1) as a peri-operative analgesic. Rabbits were housed individually in standard laboratory cages throughout. Data were collected at three time periods: 24-21 h prior to surgery (T1) and, post-surgery, 0-3 h (T2) and 3-6 h (T3). Behavioural changes were identified using Observer XT, significance of which was assessed using a Friedman's test for several related samples. The frequency or duration of numerous pre-operative behaviours was significantly reduced in T2 and T3, as compared to T1. Conversely, novel or rare behaviours had either first occurrence or significant increase in T2 into T3 as compared to T1, these include ‘full-body-flexing’, ‘tight-huddling’, ‘hind-leg-shuffling’. We conclude that reduced expression of common pre-operative behaviours and the appearance of certain novel post-operative behaviours may be indicative of pain in rabbits. Behaviours identified as increased in T2 as compared to T1 but not consistently elevated into T3 were considered separately due to the potentially confounding effect of anaesthesia recovery. These included lateral lying, ‘drawing-back’, ‘staggering’ and ‘closed eyes’. We postulate that for effective application of best-practice post-operative care, informed behavioural observation can provide routes by which carers may identify requirements for additional post-operative analgesia. Additionally, improvement of the peri-operative pain management regimen may be required to ameliorate the immediate effects of abdominal surgery. Comparisons with other studies into post-operative pain expression in rabbits suggest behavioural indicators of pain may differ, depending on housing and surgical procedure.

Intra-abdominal castration in the rat

Normal rat posture results in proximity of the scrotum to bedding and feces, which predisposes rats to postoperative complications if castration is done using standard scrotal and prescrotal approaches. This column describes a ventral abdominal approach for castration in the rat.