Abstract

Basic concepts of animal welfare including five domains and their indices are introduced, and a few minimally invasive surgical techniques that are easily amenable to small animal clinics are described.

General Understanding of Animal Welfare

Animal welfare is affected by five domains: nutrition, environment, health, behavior, and mental status. The first four are physical components.¹

Nutrition detriments including water and food deprivation, and malnutrition can be estimated by body condition score. Environment is a challenging outdoor and indoor environmental condition, whose influence is ascertained by measurement of body temperature, occurrence and shivering and panting, and seeking shade. The health domain includes disease, injury and functional impairment. This is evaluated by various clinical outcomes. The domain of behavior comprises individual, group, or interactive restrictions that manifest as self-mutilation, stereotypical behavior, and aggressive behavior. The domain of mental state encompasses unpleasant or noxious experiences including thirst, hunger, nausea, pain, fear, anxiety, and loneliness, which are measured by physiological indices and observance of behavior. Animal welfare is determined by all five welfare domains, which have an influence on each other. Examples are food deprivation leading to hunger and joint inflammation leading to pain. Also, direct consideration of the mental domain itself allows evaluation of inputs that are largely independent on the other four domains (e.g., inputs such as those linked to a perceived threat manifesting as fear).

In a 2010 survey concerning animal welfare in Korea, 93.8% of the respondents agreed they had a responsibility to minimize animal pain.²

Minimally Invasive Surgery to Improve Animal Welfare Status

Minimally invasive techniques lead to short operation and recovery time. Animal health is being improved and behavior of animal is less confined because of short hospitalization times resulting from rapid recovery. Mental problems including pain and fear are best dealt with if recognized early in life. Canine welfare is improved in dogs undergoing minimally invasive surgery, compared to dogs undergoing general surgery.

A Self-Expandable Intratracheal Nitinol Stent for the Tracheal Collapse in Dogs

Tracheal collapse in dogs, due to dorsoventrally dynamic narrowing of the tracheal lumen during the respiratory cycle, mainly occurs in toy or miniature dog breeds.

Minimally invasive techniques used to treat tracheal collapse or tracheal stenosis in humans, dogs and cats include the implantation of intraluminal stainless-steel or nitinol stents.

Technical success was achieved in all 4 client-owned dogs.³ Radiographs taken after stent implantation showed widening of the previously narrowed tracheal lumen in all four dogs. Soon after stent implantation, the respiratory dyspnea in all dogs improved dramatically, and the dogs resumed almost normal activity. Between 4 and 7 months after implantation, the dyspnea caused by tracheal collapse showed substantial recovery, and the radiographs showed no evidence of stent collapse, shortening or migration (Table 1).

Stent implantation is a minimally invasive, effective, easy and brief procedure that can be used to treat tracheal collapse.

Table 1. Effect of self expandable intratracheal nitinol stent on clinical signs in dogs with tracheal collapse.

*Grade I tracheal collapse is a 25% reduction in lumen diameter, Grade II collapse is a 50% reduction in lumen diameter, Grade III collapse is a 75% reduction in lumen diameter, Grade IV collapse the lumen is obliterated on lateral thoracic radiograph. M: male, F: female, FS: neutered female. CT-TT: cervical trachea to thoracic trachea.

Surgical Removal of Heartworm Using Flexible Alligator Forceps in Dogs

The flexible alligator forceps technique for surgical treatment of heartworm infection provides many advantages, including minor invasiveness, excellent heart chamber accessibility, and the actual removal of adult heartworm that could cause thrombosis.

Twenty males and twenty females with heartworm infection were studied.⁴ Mean (±SD) age for forty dogs was 5.8 ± 2.7 years (range, 2 to14 years). Mean body weight (±SD) for forty dogs was 10.3 ± 6.1 kg (range, 2.1 to 31 kg). All dogs survived and were healthy on physical examination 7 days post-operatively. Negative reactions were obtained on antigen ELISA test kit (SNAP®, IDEXX Laboratories, Inc, USA) and heartworms were not detected on echocardiography 7 days after surgical treatment in the 30 dogs. The mean number (±SE) of heartworms removed was 11 ± 1.1 (range, 1 to 33). Mean surgical time (±SE) was 30.0 ± 7.6 min (range, 20 to 50). Mean number (±SE) of trials was 10.83 ± 0.5 (range, 6 to 15). Removal rates according to removal areas of the RV, MPA, RPA, and LPA were 0.5%, 29.6%, 47.4%, and 22.5% respectively. There was significant correlation among removal rates according to removal areas of the RV, MPA, RPA, and LPA (P < 0.01).

Intradiscal Oxygen-Ozone Injection Therapy for Thoracolumbar Intervertebral Disc Herniations (IVDH) in Dogs

Oxygen-ozone (O₂-O₃) injection therapy was first used in human medicine to treat disc herniation. This is currently available in the management of disc herniation as one of the various minimally invasive treatments. O₂-O₃ therapy was reported to give a satisfactory clinical result via a well-tolerated, low-cost procedure. It is based on the action of O₂-O₃ in bring about shrinkage of the herniated disc and an anti-inflammatory and analgesic effect on the compressed spinal cord.

The overall characteristics and outcomes of dogs treated with oxygen-ozone injection were summarized in Table 2.⁵ Their body weights ranged from 4.1 to 7.6 kg. Three dogs showed paraparesis and the rest paraplegia. Neither urinary nor fecal dysfunction was observed. The total number of lesions was ten sites in five dogs. Three dogs presented multiple lesions from T9 to L4 while the remainder had only one IVDH respectively.

The total procedure time was about 20 minutes, estimated from the induction of anesthesia to the removal of spinal needle. All dogs recovered from the procedure without any complications.

All five dogs showed improvement after O₂-O₃ injection. Of the five dogs, four dogs ambulated normally within 12 days after the procedure, within a mean period of 5.75 (SD: ± 4.27) days. Case 1 also regained ambulatory function slowly, yet the dog presented stumbling gait to the end of monitoring.

Table 2. Characteristics, clinical signs and outcomes of five dogs with thoracolumbar intervertebral disc herniation which were treated with O₂-O₃ injection.

a. Case 2 to 5 showed no recurrence up to 20 months of monitoring after O₂-O₃ injection; b. Case 1 was able to walk progressively but revealed a mild decreased proprioceptive reflex 20 months after O₂-O₃ injection.

After the long follow-up period, none showed any sequel or signs of recurrence. Owners were satisfied with the clinical outcomes up to 20 months.

Reduction of herniated disc lesions after O₂-O₃ injection was confirmed with CT at 5 weeks after the procedure. The A-index, which indicates the degree of disc shrinkage, varies among the discs ranging from 2.69% to 13.89% with an average of 8.8% (SD: ± 3.82).

References

1.  Mellor DJ, Patterson-Kane E, Stafford KJ. The Sciences of Animal Welfare. Oxford, Wiley-Blackwell, 2009:72–94.

2.  National Veterinary Research & Quarantine Service. Survey of Public Opinion on Animal Welfare. Publish ID 11-1541002-000128-01 (Gallup 201011047), Seoul, Gallup Korea. 2010:11–14.

3.  Kim JY, Han HJ, Yoon HY, et al. The safety and efficacy of a new self-expandable intratracheal nitinol stent for the tracheal collapse in dogs. J Vet Sci 2008;9:91–93.

4.  Yoon HY, Jeong SW, Kim JY, et al. Surgical treatment of heartworm infection using flexible alligator forceps in dogs. Indian Vet J 2009;86:1230–1233.

5.  Han HJ, Kim JY, Jang HY, et al. Fluoroscopic-guided intradiscal oxygen-ozone injection therapy for thoracolumbar intervertebral disc herniations in dogs. In Vivo 2007;21:609–614.