No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Pain and analgesia following onychectomy in cats: A systematic review
Abstract
Objectives:
To systematically review published studies evaluating pain associated with onychectomy in cats, and to assess the efficacy of the analgesic therapies applied.
Databases used:
Four sources were used to identify manuscripts for review. Databases searched were those of the National Library of Medicine, EMBASE and CAB International. In addition, pertinent references in the bibliographies of included articles were retrieved.
Results:
Twenty manuscripts published in refereed journals were reviewed. These included papers reporting 18 clinical trials and two studies conducted in conditioned research cats. Twelve analgesics were evaluated, including seven opioids, four non-steroidal anti-inflammatory drugs and one local anesthetic. Nine studies involved a direct comparison of analgesic agents. Limb use was abnormal when measured at 2 and 12 days following onychectomy, and neither fentanyl patch nor butorphanol administration resulted in normal use of the surgical limb. In another study, cats evaluated at 6 months after this surgery were not lame. Differing surgical techniques were compared in six studies; the results indicated that pain scores were lower after laser surgery than after scalpel surgery. The difficulties associated with assessing pain in cats and the lack of sensitivity of the evaluation systems utilized were highlighted in many of the studies. Huge variations in dose and dosing strategies had significant impacts on drug efficacy. Statistically significant differences among treatments were found in most studies; however, no clearly superior analgesic treatment was identified. A combination of meloxicam or robenacoxib with an opioid may provide more effective analgesia and should be evaluated.
... 2,[4][5][6] Pain, lameness and changes in behavior can also be present in cats regardless of the method of amputation or anesthetic and analgesic protocols. 7,8 Scratching is a natural behavior that is inherited and learned in cats that allows them to deposit pheromones, stretch and sharpen their claws. 9,10 Because scratching is a natural behavior that cannot be eliminated, treatment recommendations focus on redirecting scratching behavior to more desirable surfaces, such as scratching posts. ...
Objectives
The aim of this study was to determine whether there was an increase in cat relinquishment for destructive scratching behavior, a change in overall feline surrender intake and euthanasia, or a change in average length of stay in a British Columbia shelter system after provincial legislation banning elective onychectomy.
Methods
Records of cats admitted to the British Columbia Society for the Prevention of Cruelty to Animals in the 36 months prior to (1 May 2015–30 April 2018, n = 41,157) and after (1 May 2018–30 April 2021, n = 33,430) the provincial ban on elective onychectomy were reviewed. Total intake numbers, euthanasia and length of stay were descriptively compared between periods. Proportions of cats and kittens surrendered for destructive scratching, as well as the proportion of cats and kittens surrendered with an owner request for euthanasia, were compared using two-sample z-tests of proportions.
Results
Destructive behavior was found to be an uncommon reason for surrender (0.18% of surrendered cats) during the study period. There was no statistically significant difference in the number of cats surrendered for destructive scratching behavior ( z = −1.89, P >0.05) after the provincial ban on elective onychectomy. On the contrary, the proportion of owner-requested euthanasias decreased after the ban ( z = 3.90, P <0.001). The total number of cats surrendered, the shelter live release rate and average length of stay all remained stable or improved following the ban, though causation could not be determined.
Conclusions and relevance
The findings in this study suggest that legislation banning elective onychectomy does not increase the risk of feline shelter relinquishment – for destructive behavior or overall – and is unlikely to have a significant effect on shelter euthanasia or length of stay.
... Opioids such as fentanyl, buprenorphine and tramadol are used for the management of maladaptive and DJD-associated pain in humans (Schaefert et al., 2015), however their role in the management of chronic pain in cats has not been elucidated. Transdermal use of fentanyl, a full μ-agonist, has been evaluated in cats undergoing ovariohysterectomy (Davidson et al., 2004) and onychectomy (Wilson and Pascoe, 2016), but not in cats with DJD-associated chronic pain. The use of buprenorphine, a partial μ-agonist and κ-antagonist, has been evaluated in multiple studies in cats, although they were also mainly focused on acute rather than chronic pain . ...
Degenerative joint disease (DJD) is one of the most common causes of chronic pain in cats. Two studies were designed to identify risk factors for DJD in 6-year-old cats by examining prospective data from a longitudinal cohort study, and compare the activity profiles and quality of life of cats with (cases) and without (controls) early owner-reported signs of impaired mobility using orthopaedic examination, accelerometry and owner-completed questionnaires (Feline Musculoskeletal Pain Index (FMPI), VetMetrica).
Binomial logistic regression using backwards elimination identified four risk factors for increased owner- reported mobility impairment score in 6-year-old cats: entire neuter status at six months of age (OR=1.97, 95%CI 1.26–3.07), sustained trauma before six years of age (OR=1.85, 95%CI 1.3–2.6), outdoor access at six years of age (OR=1.67, 95%CI 0.96–2.9), and overweight/obese status at six years of age (OR=1.62, 95%CI 1.13–2.33). Case cats scored significantly lower than control cats for the FMPI (p=0.003) and the VetMetrica domain of comfort (p=0.002), but not vitality (p=0.009) or emotional wellbeing (p=0.018). Total pain (p<0.0001), crepitus (p=0.002) and thickening (p=0.003) scores were higher in case cats. Accelerometry differentiated cases from controls with a 90.9% accuracy.
Risk factor analysis demonstrated that obesity, outdoor access, and a history of trauma predispose cats to developing DJD, whereas neutering appears to decrease that risk. Changes in joint health as detected by orthopaedic examination and accelerometry reflected owner-reported mobility changes, differentiating cats with early DJD-related signs from healthy cats, whilst the VetMetrica comfort domain score indicated an impaired quality of life of cats with early DJD compared to healthy cats. Being able to recognise signs of mobility impairment earlier would allow interventions aimed at slowing DJD progression, thereby improving feline health and welfare. These findings have identified that orthopaedic examination, FMPI and accelerometry are effective in identifying early DJD-related mobility changes in cats.
... It should come as no surprise that evidence shows declawing causes pain in cats, in part due to a number of surgical sequelae including retained bone fragments, osteomyelitis, excessive tissue handling during surgery, and complications from bandaging (124). While pain is an expected outcome of any surgery and should be ameliorated appropriately, there is evidence that there is short-and long-term pain due to onychectomy (124)(125)(126)(127)(128)(129). Behaviors indicative of pain, such as forepaw shaking and laying on their side, were seen in cats that were declawed compared to those having a sham procedure performed (125). ...
Veterinarians perform surgery for a number of reasons, from treating a problem to preventing future problems. There is an inextricable link between the physical and psychological aspects of an animal's health, and surgery is often a conduit to bridge that gap. Some surgical procedures can affect an animal's behavior, such as castration, and some pose an ethical dilemma, such as ear cropping and declawing. Ameliorating pain, decreasing stressful experiences for the animal, and identifying and treating concurrent problem behaviors are hallmarks of improving animal welfare. The purpose of this article is to outline some of these interrelationships and ethical dilemmas, providing evidence-based verification as applicable.
... Currently, opioid drugs and α-2 agonists are used for postoperative pain management in cats. Such treatments have many advantages including good sedation, good analgesia and lower dose requirements of either opioid drug or α-2 agonist due to synergistic effects (Slingsby et al. 2010;Mathews et al. 2014;Steagall et al. 2014;Bortolami and Love 2015;Merola and Mills 2015;Wilson and Pascoe 2016). However, the effects of a combination of a buprenorphine transdermal patch with meloxicam administered via subcutaneous (s.c.) injection on postoperative pain in cats have not been previously studied. ...
The purpose of this prospective double blind clinical study was to evaluate the analgesic efficacy of meloxicam with/without a buprenorphine patch for pain management after ovariohysterectomy in cats. Cats were randomly divided into two groups: ten cats were treated with meloxicam s.c. after ovariohysterectomy (Group A), and eight cats were treated with s.c. meloxicam and a 20 µg/h buprenorphine transdermal patch (Group B). For patch treatment, the cat’s hair was clipped on the left side in the thoracic area. Pain scores were assessed at 0.5, 1, 2, 4, 6, 8, 24 and 30 h post-ovariohysterectomy extubation. To evaluate postoperative pain, 4A-VET pain scale and visual analogue scale pain scores were used. In addition, blood was collected from all cats to determine the cortisol levels at –2 h and at 0.5, 4, 6 and 24 h after extubation. The 4A-VET scores for Group B were significantly lower at 1, 4, 6, 8, 24 and 30 h than the scores for Group A. The visual analogue scale pain scores for Group B were significantly lower at 4, 6, 24 and 30 h than the scores for Group A. Serum cortisol concentrations were not significantly different between Groups A and B at any of the measured intervals. There was a significant positive correlation between postoperative visual analogue scale and 4A-VET pain scores in both groups. Our results should be subject to careful interpretation as the study was limited by its small sample size and by observer subjectivity.
... One study identified a lack of a sensitive pain assessment tool in published declaw studies reviewed. 30 There is also a lack of published research in declawed cats with respect to the prevalence of long-term disease, other than nail regrowth, associated with P3 bone remnants. This is an important consideration given that an estimated 25% of the US domestic cat population is declawed. ...
Objectives
The aim of this study was to assess the impact of onychectomy (declawing) upon subsequent development of back pain and unwanted behavior in cohorts of treated and control cats housed in two different locations.
Methods
This was a retrospective cohort study. In total, there was 137 declawed and 137 non-declawed cats, of which 176 were owned cats (88 declawed, 88 non-declawed) and 98 were shelter cats (49 declawed and 49 non-declawed). All cats were physically examined for signs of pain and barbering. The previous 2 years of medical history were reviewed for documented unwanted behavior such as inappropriate elimination and biting with minimal provocation and aggression. All declawed cats were radiographed for distal limb abnormalities, including P3 (third phalanx) bone fragments. The associations of declaw surgery with the outcomes of interest were examined using χ ² analysis, two sample t-tests and manual, backwards, stepwise logistic regression.
Results
Significant increases in the odds of back pain (odds ratio [OR] 2.9), periuria/perichezia (OR 7.2), biting (OR 4.5) and barbering (OR 3.06) occurred in declawed compared with control cats. Of the 137 declawed cats, 86 (63%) showed radiographic evidence of residual P3 fragments. The odds of back pain (OR 2.66), periuria/perichezia (OR 2.52) and aggression (OR 8.9) were significantly increased in declawed cats with retained P3 fragments compared with those declawed cats without. Optimal surgical technique, with removal of P3 in its entirety, was associated with fewer adverse outcomes and lower odds of these outcomes, but operated animals remained at increased odds of biting (OR 3.0) and undesirable habits of elimination (OR 4.0) compared with non-surgical controls.
Conclusions and relevance
Declawing cats increases the risk of unwanted behaviors and may increase risk for developing back pain. Evidence of inadequate surgical technique was common in the study population. Among declawed cats, retained P3 fragments further increased the risk of developing back pain and adverse behaviors. The use of optimal surgical technique does not eliminate the risk of adverse behavior subsequent to onychectomy.
This chapter presents a concise description of the pathophysiology, diagnosis, and treatment of the most relevant canine and feline skin and musculoskeletal diseases. An emphasis is given to the impact of these diseases on anesthetic and analgesic management of patients. In some instances, skin and musculoskeletal disease is presented as a secondary complication rather than the main clinical concern. Skin burns are a result of thermal, chemical, electrical, or radiation injury. The prevalence of acute neuropathic pain in humans with burns can be up to 52% for years after the injury and is associated with an increased extent/percentage of body surface burns at presentation. These patients are at high risk of developing chronic pain syndromes following healing. Auricular diseases can be particularly painful, especially in the presence of chronic inflammation and neoplasia. Malignant hyperthermia episodes may occur in healthy animals without a previous history of anesthetic problems.
Cats present unique challenges in oral surgery. Tooth resorption commonly leads to root fractures. Radiographic assessment is mandatory prior to determining whether to perform coronectomy or to extract a resorbing tooth in toto. Fractured canine teeth almost always have pulp involvement, which necessitates either extraction or endodontic therapy. Proper instrument selection can help prevent complications when performing extractions in cats.
Surgery can be challenging in exotic pets owing to their small size and blood volume, and their increased anesthetic risk compared with small animals. Various devices are available to facilitate suturing, cutting, and hemostasis in the human and veterinary fields. These surgical equipment improve the simplicity, rapidity, and effectiveness of surgery. Vessel-sealing devices, radiosurgery, lasers, and ultrasound devices are commonly used because of their ease of use and increase in surgical efficiency. Other surgical devices are available (eg, stapling devices) but are not discussed in this article.
Treatment of acute pain presents several challenges in feline practice. This chapter presents an overview of epidemiological data on the use of analgesics in cats and current challenges and principles of feline acute pain management. Multimodal and preventive analgesia involving nonpharmacological therapies and local anesthetics, opioids and nonsteroidal anti-inflammatory drugs (NSAIDs) are the first line of treatment in acute pain. The importance of nonpharmacological therapy should not be underestimated. Other therapies including agonists of α2-adrenergic receptors, tramadol, tapentadol, gabapentin and ketamine are presented as the second line of treatment for severe acute pain but also for prevention of persistent postsurgical pain.
The efficacy and safety of robenacoxib were assessed for the control of postoperative pain and inflammation in cats. The study was a multicenter, prospective, randomized, blinded, and parallel group clinical trial. A total of 249 client-owned cats scheduled for forelimb onychectomy plus either ovariohysterectomy or castration surgeries were included. All cats received butorphanol prior to anesthesia and forelimb four-point regional nerve blocks with bupivacaine after induction of general anesthesia. Cats were randomized to receive daily oral tablet robenacoxib, at a mean (range) dosage of 1.84 (1.03-2.40) mg/kg (n = 167), or placebo (n = 82), once prior to surgery and for two days postoperatively. Significantly (P < 0.05) fewer robenacoxib cats received additional analgesia rescue therapy (16.5%) than placebo cats (46.3%). Pain elicited on palpation of the soft tissue incision site, behavior following social interaction, and posture assessed during the first 8 hours after extubation were significantly (P < 0.05) improved in cats receiving robenacoxib. Frequency of reported adverse clinical signs, hematology, serum chemistry and urinalysis variables, and body weight changes weresimilar between groups. In conclusion, robenacoxib was effective and well tolerated in the control of postoperative pain and inflammation in cats undergoing onychectomy with ovariohysterectomy or castration.
Three- or 5-day courses of meloxicam [0.2 mg/kg body weight (BW) subcutaneously pre- or postoperatively on Day 1 followed by 0.05 mg/kg BW, PO per day thereafter] were assessed for analgesic efficacy and safety in 50 client-owned cats undergoing onychectomy and sterilization. Primary outcome parameters were analgesia score, gait/lameness score, and need for rescue analgesia assessed at times 0, 1, 4, 7, 24, 28, 35, 48, 52, 57 hours and on Day 5. Packed cell volume/total solids and serum biochemistry were assessed at time 0 and Days 3 and 5. There were no differences in efficacy and safety parameters regardless of the treatment protocol employed and no cat required rescue analgesia. The patients that received meloxicam preoperatively had statistically better gait/lameness scores than those that received meloxicam postoperatively, supporting the principle of preemptive analgesia.
The purpose of this study was to investigate and compare the effects of medetomidine and xylazine on some neurohormonal and metabolic variables in healthy cats. Five cats were used repeatedly in each of 11 groups, which were injected intramuscularly with physiological saline solution (control), 20, 40, 80, 160, and 320 microg/kg of medetomidine, and 0.5, 1, 2, 4, and 8 mg/kg of xylazine. Blood samples were taken over 24 h from the jugular vein for determination of plasma glucose, insulin, cortisol, epinephrine, norepinephrine, glucagon, and nonesterified fatty acid concentrations. Both medetomidine and xylazine induced remarkable hyperglycemia that was dose-dependent except for the response to medetomidine from 0 to 3 h. Both agents suppressed epinephrine and norepinephrine release but not in a dose-dependent manner at the tested dosages. Both agents inhibited insulin release and lipolysis, with similar potency, and tended to suppress cortisol release. The glucagon levels did not change significantly in any of the groups. These results suggest that the effects of medetomidine and xylazine on glucose metabolism and catecholamine release may not be due only to the actions mediated by alpha2-adrenoceptors.
The CONSORT (Consolidated Standards of Reporting Trials) statement is used worldwide to improve the reporting of randomized, controlled trials. Schulz and colleagues describe the latest version, CONSORT 2010, which updates the reporting guideline based on new methodological evidence and accumulating experience.
To identify feline and household characteristics associated with relinquishment of a pet cat to an animal shelter.
Case-control study.
Households that relinquished cats for adoption (case households) and a random sample of current cat-owning households in the same community (control households).
Potentially modifiable risk factors with the highest population attributable risk for relinquishment were owners having specific expectations about the cat's role in the household, allowing the cat outdoors, owning a sexually intact cat, never having read a book about cat behavior, cats having daily or weekly inappropriate elimination, and inappropriate care expectations. Frequency of inappropriate elimination and aggression toward people were not associated with declaw status, but these behaviors were more common among sexually intact cats, compared with sterilized cats. Owners of cats in case households were more likely than owners in control households to cite cost of sterilization as a reason a cat was sexually intact. Cats found as strays and cats acquired with minimal planning were at decreased risk of relinquishment.
The identified risk factors can be modified by cat owners and veterinarians to decrease the estimated 4 million cats euthanatized annually in animal shelters. Owner education programs are needed as well as increased awareness on the part of cat owners and veterinarians of the importance of resolving feline inappropriate elimination problems.
To evaluate the ability of various subjective and objective measurements to determine the presence and degree of postoperative pain in cats.
Randomized controlled prospective clinical study.
18 healthy client-owned cats.
Cats were randomly assigned to 3 groups of 6: control, tenectomy, and onychectomy. Jugular catheters were placed the day prior to surgery. All surgeries were performed by the same surgeon, and all observations were made by the same blinded trained observer. One hour prior to surgery and at assigned intervals for 36 hours after surgery, heart rate, respiratory rate, and rectal temperature were measured. Scores were assigned for 3 interaction responses, including response to palpation, by use of simple descriptive scales, and to 2 pain assessments by use of visual analogue scales. Blood was collected to measure plasma beta-endorphin and cortisol concentrations. Butorphanol was administered to all cats before surgery and to any cat subjectively assessed to be experiencing pain after surgery.
Only visual analogue scale scores and response to palpation scores differed significantly between control and surgical groups.
Determination of the presence of pain in cats can be made on the basis of observation and interaction by a trained observer. Physiologic measurements, including plasma cortisol and beta-endorphin concentrations, did not differentiate between control cats and cats that underwent surgery.
To compare the incidence of behavior problems following tendonectomy or onychectomy in cats, as well as attitudes of owners following these procedures.
Nonrandomized clinical trial.
18 cats that underwent tendonectomy and 39 cats that underwent onychectomy.
Owners of cats that underwent tendonectomy or onychectomy between February 1993 and May 1998 were contacted by telephone and asked several questions regarding reasons for surgery as well as complications and behavioral changes in cats following surgery.
The most common reason for considering tendonectomy or onychectomy was to avoid damage caused by the cat scratching household materials. Avoidance of injury to humans or animals was chosen more often by owners whose cats underwent onychectomy than those that underwent tendonectomy. Tendonectomy was more likely to have been recommended by veterinarians than onychectomy. Significantly more cats that underwent tendonectomy (67%) than onychectomy (44%) returned to normal activity within 3 days after surgery. Significant differences were not detected regarding behavior problems after surgery.
Although tendonectomy and onychectomy involved some medical complications and behavior changes following surgery, owners had positive attitudes regarding both surgeries after the immediate postoperative period. Tendonectomy may be a humane alternative to onychectomy, although owners need to be advised that nail trimming is still necessary in cats after surgery.
To determine peak vertical force (PVF) and vertical impulse (VI) in cats that had or had not undergone bilateral forelimb onychectomy.
26 healthy adult cats.
Onychectomized cats (n = 13) had undergone surgery more than 6 months prior to the study. The PVF and VI were collected from all limbs of each cat with a 2-m pressure platform walkway. Cats were allowed to walk at a comfortable velocity, and acceleration was restricted to +/- 0.5 m/s2. Five valid trials were recorded for each cat with all trials collected in a single 1-hour session. All forces were normalized to and expressed as a percentage of the cat's body weight.
Gait data were successfully collected in all cats. No significant difference was found for PVF or VI between cats that had or had not had onychectomy. Limb loads were greater in forelimbs than hind limbs for all trials. Mean PVF and VI in the forelimbs of cats in the nononychectomy group were 56.41% and 18.85%, respectively. Mean PVF and VI in the hind limbs of cats in the nononychectomy group were 50.22% and 14.56%, respectively.
Gait analysis was successfully performed in cats with a pressure platform walkway. The absence of differences in PVF and VI between the 2 groups of cats suggests that bilateral forelimb onychectomy did not result in altered vertical forces measured more than 6 months after surgery in cats.
To evaluate the analgesic effects of topical administration of bupivacaine, i.m. administration of butorphanol, and transdermal administration of fentanyl in cats undergoing onychectomy.
Prospective study.
27 healthy adult cats.
Cats were randomly assigned to 1 of 3 treatment groups, and unilateral (left forefoot) onychectomy was performed. Gait analysis was performed before and 1, 2, 3, and 12 days after surgery. All forces were expressed as a percentage of the cat's body weight.
On day 2, peak vertical force (PVF) was significantly decreased in cats treated with bupivacaine, compared with cats treated with butorphanol or fentanyl. The ratio of left forelimb PVF to PVF of the other 3 limbs was significantly lower on day 2 in cats treated with bupivacaine than in cats treated with fentanyl. No significant differences in vertical impulse (VI) were found between groups on any day. Values for PVF, VI, and the PVF ratio increased progressively following surgery. However, for all 3 groups, values were still significantly decreased, compared with baseline values, 12 days after surgery.
Results suggest that limb function following onychectomy is significantly better in cats treated with fentanyl transdermally or butorphanol i.m. than in cats treated with bupivacaine topically. Regardless of the analgesic regimen, limb function was still significantly reduced 12 days after surgery, suggesting that long-term analgesic treatment should be considered for cats undergoing onychectomy. Irrigation of the surgical incisions with bupivacaine prior to wound closure cannot be recommended as the sole method for providing postoperative analgesia in cats undergoing onychectomy.
This study compared patient discomfort for 10 d following feline onychectomies performed using a CO2 surgical laser versus a scalpel blade. Both techniques appeared to result in discomfort of a similar duration, although the laser caused significantly less lameness than blade excision during the first 7 d.
The effectiveness of analgesia provided by the intramuscular (i.m) injection of a single dose either of ketoprofen (20mg/kg) or pentazocine (20mg/kg) was compared in cats undergoing onychectomy. Scores were assigned for the degree of pain, lameness, temperament and appetite at 1, 2, 3, 5, and 24 hours post-operatively. Heart and respiratory rates, as well as rectal temperature were also measured as indices of pain over the same period of time.
In this study, either of ketoprofen or pentazocine produces better (i.e. lower) scores than the control group for the degree of pain, lameness, temperament and appetite within the first 2-3 hours. Heart and respiratory rates were also lower than the control group while there was no significant (P>0.05) alteration in rectal temperature.
It was concluded that single i.m dose of both ketoprofen and pentazocine are somewhat equally effective and safe in healthy cats and that analgesia is beneficial following onychectomy in cats.
(Tropical Veterinarian: 2002 20(2): 101-111)
The current prevalence of onychectomy (declawing) in cats is unknown, and education regarding the procedure appears to vary greatly among veterinary schools. The purpose of this project was to determine the prevalence of onychectomized cats near Raleigh, NC and to document the frequency and style (laboratory or lecture) with which the procedure is taught in USA veterinary schools.
One thousand seven hundred ninety four cats ranging in age from 8 days to 21 years, of which 938 (52.3%) were female and 1719 (95.8%) were sterilized.
Data were collected over a 10-week period regarding cats seen for appointments in five veterinary facilities (two cat-only, two general, and one tertiary). Data collection included signalment and onychectomy status. During this time, 28 veterinary schools were polled regarding education of veterinary students in onychectomy.
Three hundred and seventy four (20.8%) cats had undergone onychectomy. A significantly higher percentage of declawed cats were seen in the general practices compared with the other practice types (p < 0.030). Younger cats had a higher rate of onychectomy (p < 0.001). Twenty-six veterinary schools responded to the survey (93%). Fourteen (54%) of the responding schools did not include in their core curriculum a lecture or surgical laboratory providing instruction in the onychectomy procedure.
Almost 21% of cats seen in veterinary hospitals near Raleigh, NC were declawed. Less than 50% of veterinary schools in the USA include a mandatory lecture or laboratory to teach the procedure. There appears to be a discrepancy between the popularity of the onychectomy procedure and the emphasis placed on relevant instruction in veterinary schools in the USA.
Declawing is controversial. To date, there has been little research to support the negative statements (of physical and emotional harm) by those critical of the procedure. Similarly, veterinary recommendations may be based on years of experience but little factual data. Cat associations and even the Canadian Veterinary Medical Association (CVMA) does not support declawing. Of the 276 owners of declawed cats surveyed for this study, all stated that declawing successfully met their objectives, and, in many cases additional benefits were listed as well. While 10 owners (4%) had a negative opinion of declawing, only two of their cats developed problems (one behavioral and one medical). Ninety-six percent of owners had a positive or very positive attitude about declawing at the time of the survey, and at least 70% reported Improved relationships with their cats. Forty-one percent of the cats went outdoors without problems after declawing. Cats declawed after age 1 had a higher incidence of postsurgical discomfort and took longer to recover.
Eighty-four female cats undergoing ovariohysterectomy in a blinded, randomised, prospective clinical study were assigned to one of three groups of 28 to receive either 0.01 mg/kg buprenorphine (group B), 4 mg/kg carprofen (group C), or the same doses of both drugs (group BC). A dynamic and interactive visual analogue scale (DIVAS) from 0 to 100 mm, and a simple descriptive scale (SDS) from 0 to 4 were used to evaluate the cats' degree of analgesia and sedation for 24 hours postoperatively. There was no significant difference in the cats' sedation scores by SDS or DIVAS, and no difference in their pain scores by DIVAS. By SDS, the cats in group BC had significantly lower pain scores than the cats in group C (P<0.001) and group B (P<0.05). Nine of the cats in group B, nine in group C and five in group BC required rescue analgesia, and the cats in group C required rescue earlier than those in group B (P<0.05).
Twenty-four healthy adult cats were anesthetized with isoflurane in oxygen. Six cats (group 1) served as controls; onychectomy of the forefeet was performed in the other three groups. Saline was administered intravenously to group 1, and morphine, xylazine, and salicylate were administered to groups 2, 3, and 4, respectively. Mixed venous blood samples were drawn for catecholamine analysis before induction of anesthesia, after recovery from anesthesia, and 30 minutes and 60 minutes after administration of the analgesic agent. Plasma catecholamine concentrations were determined by high performance liquid chromatography. Isoflurane anesthesia alone induced a transient increase in epinephrine concentration. Norepinephrine and epinephrine concentrations increased significantly after onychectomy. Morphine and xylazine significantly decreased postoperative norepinephrine and epinephrine concentrations; salicylate did not.
One hundred sixty-three cats underwent onychectomy from January 1985 to November 1992. Onychectomy was performed with guillotine-type nail shears (62%), surgical blade (24.5%), or both (8.6%), and wound closure consisted of bandages alone (61.3%), bandages after suture closure (26.4%), or tissue adhesive application (9.2%). The duration of surgery was significantly longer when onychectomy was performed with a blade or when suture closure was used instead of bandages alone (P < .05). Fifty percent of the cats had one or more complications immediately after surgery. Early postoperative complications included pain (38.1%), hemorrhage (31.9%), lameness (26.9%), swelling (6.3%), or non-weight-bearing (5.6%), and were observed more frequently after blade onychectomy (P < .001). Follow-up was available in 121 cats; 19.8% developed complications after release. Late postoperative complications included infection (11.6%), regrowth (7.4%), P2 protrusion (1.7%), palmagrade stance (1.7%), and prolonged, intermittent lameness (0.8%). Late postoperative complications were observed more frequently after shears onychectomy (P = .018). Use of tissue adhesive was associated with more postoperative lameness (P < .02) and, when used after shears onychectomy, with more infections (P = .049).
Plasma catecholamine concentrations in response to onychectomy were examined in 27 cats receiving different anesthetic regimens. Each cat was anesthetized with a dissociative-tranquilizer combination, and onychectomy was performed on 1 forefoot. One week later, each cat was anesthetized with the same dissociative-tranquilizer combination plus either butorphanol or oxymorphone, and onychectomy was performed on the other forefoot. Four treatment groups were studied: tiletamine-zolazepam and tiletamine-zolazepam-butorphanol combinations were administered to group-1 cats, ketamine-acepromazine and ketamine-acepromazine-butorphanol combinations were administered to group-2 cats, tiletamine-zolazepam and tiletamine-zolazepam-oxymorphone combinations were administered to group-3 cats, and ketamine-acepromazine and ketamine-acepromazine-oxymorphone combinations were administered to group-4 cats. All drug combinations were administered IM. Central venous blood samples were drawn for catecholamine analysis after injection of drug(s), after onychectomy, and 1, 2, and 4 hours after injection. Tiletamine-zolazepam alone or tiletamine-zolazepam-butorphanol prevented epinephrine release for 2 hours after injection of drug(s). Norepinephrine concentration increased significantly (P < 0.05) from baseline after onychectomy for tiletamine-zolazepam-butorphanol and at 4 hours for tiletamine-zolazepam and tiletamine-zolazepam-butorphanol. After onychectomy, there was no difference in epinephrine values between tiletamine-zolazepam and tiletamine-zolazepam-oxymorphone. Ketamine-acepromazine prevented increases in norepinephrine and epinephrine concentrations for up to 2 hours after surgery. Addition of butorphanol to ketamine-acepromazine decreased norepinephrine values immediately after onychectomy. Addition of oxymorphone to ketamine-acepromazine resulted in lower epinephrine values 4 hours after surgery.
Postoperative complications (POC) that developed in dogs and cats that underwent elective ovariohysterectomy, castration, and declaw at a veterinary teaching hospital were determined by examining the computerized abstracts of the medical records and by examining a random sample of the paper medical records. When the computerized abstracts were examined, POC were found to have occurred in 62 (6.1%) of 1,016 dogs. One dog died and 6 others developed major complications. Postoperative complications were found to have occurred in 38 (2.6%) of 1,459 cats. Two cats died and 1 was euthanatized. Four other cats developed major complications. Complete paper medical records for 218 dogs and cats were examined. When the paper medical records were examined, the proportions of dogs and cats with POC were 19.4% and 12.2%, respectively. These proportions were 4 to 7 times higher than when the computerized abstracts were the data source. Results of this study indicate that the frequency of clinically relevant POC of elective surgeries in dogs and cats is substantial. Examination of the computerized abstracts of medical records at this hospital allowed us to rapidly identify cases that could be included in the study but the frequency of POC would be significantly underestimated if paper records were not also assessed.
To identify clinical indicators that may help identity postoperative pain in cats after ovariohysterectomy.
Healthy, laboratory animal source cats.
Clinical indicators of pain were identified, and relief from pain in response to butorphanol was studied in 5 groups of cats. 10 cats had 1 hour of general anesthesia only, followed by recovery without additional medication. 10 cats had general anesthesia and ovariohysterectomy, followed by recovery without additional medication. 10 cats had general anesthesia, ovariohysterectomy, and postoperative administration of 0.1 mg of butorphanol/kg of body weight. Another 10 cats had general anesthesia, ovariohysterectomy, and postoperative administration of 0.3 mg butorphanol/kg. 10 cats received 0.1 mg of butorphanol/kg, IM, only. Samples and recorded data were obtained before, during, and after the anesthesia period. Clinical variables measured included heart rate, blood pressure, respiratory rate, rectal temperature, PCV, and blood glucose concentration. Results were compared with changes in norepinephrine, epinephrine, and cortisol concentrations.
Cats that did not receive analgesics had higher cortisol concentration than did cats without surgery and cats that received butorphanol after surgery. Systolic blood pressure measured by ultrasonic Doppler was found to be predictive of cortisol concentration, using a multiple linear regression model.
Cortisol concentration increased in response to surgical stress and pain, and this increase was diminished by use of butorphanol.
Systolic blood pressure was the best clinical predictor of postoperative pain.
Eighteen cats that each underwent an elective onychectomy were evaluated using a double-blind study design to determine if wound irrigation with bupivacaine prior to wound closure would decrease postoperative pain. The cats were divided alternately into an experimental group (n = 9) and a control group (n = 9). The experimental patients received bupivacaine in each incision prior to closure. The control patients received saline in each incision prior to closure. The patients were evaluated for postoperative pain using a pain-score system. The bupivacaine-treated patients had a significantly higher mean pain score at two hours following recovery from anesthesia than the saline-treated patients. At three hours following recovery from anesthesia, pain scores were not significantly different.
To evaluate adequacy of analgesia provided by postoperative administration of butorphanol to cats undergoing onychectomy.
Randomized controlled trial.
63 cats undergoing elective onychectomy.
Cats were randomly assigned to a treatment (n = 42) or control group (21). Cats in the treatment group were given butorphanol parenterally immediately and 4 hours after surgery and orally for 2 days after surgery. Rectal temperature, heart rate, and respiratory rate were recorded and scores were assigned for temperament, recovery, sedation, analgesia, and lameness for the first 24 hours after surgery. Owners provided scores for appetite, personality, and lameness the first and second days after discharge from the hospital.
Heart rate, respiratory rate, rectal temperature, and temperament and sedation scores were not significantly different between groups at any evaluation time. Recovery scores were significantly better for butorphanol-treated than for control-group cats 10 minutes after extubation. Analgesia scores were significantly better for butorphanol-treated than for control-group cats between 5 and 24 hours after surgery. Fewer butorphanol-treated than control-group cats were lame at the time of discharge from the hospital. The first day after discharge, owners reported that percentages of butorphanol-treated cats that ate normally, acted normally, and had only mild or no lameness were significantly higher than percentages of control-group cats that did. Significant differences between groups were not detected the second day after discharge.
Results suggest that for cats undergoing onychectomy, administration of butorphanol the day of surgery and the first full day after surgery provides effective analgesia and improves recovery, appetite, and gait.
To compare short- and long-term complications after tenectomy of the deep digital flexor tendons or onychectomy and owner satisfaction with these surgical procedures.
Prospective cohort study.
20 cats undergoing tenectomy and 18 cats undergoing onychectomy.
Cats undergoing tenectomy or onychectomy were monitored for a minimum of 5 months to enable comparison of type and frequency of complications. Owner satisfaction was also assessed.
Cats undergoing tenectomy had significantly lower pain scores 24 hours after surgery, compared with those undergoing onychectomy. Type and frequency of other complications did not differ between procedures. Owners appeared to be less satisfied with the tenectomy procedure than with the onychectomy procedure, although scores for satisfaction with each procedure were not significantly different.
Owners should be aware of the high complication rate for both procedures and of the need for constant trimming of claws of cats that have undergone tenectomy.
To evaluate efficacy and safety of using transdermal fentanyl patches (TFP) for analgesia in cats undergoing onychectomy.
Randomized controlled clinical trial.
45 client-owned cats weighing > or = 2.7 kg (5.9 lb) undergoing onychectomy, onychectomy and ovariohysterectomy, or onychectomy and castration.
Cats were randomly assigned to be treated with a TFP (25 micrograms/h) or butorphanol; TFP were applied a minimum of 4 hours before surgery (approx 8 hours prior to extubation). Rectal temperature, heart rate, respiratory rate, force applied by the forelimbs, and serum fentanyl concentration were measured, and temperament, recovery, degree of sedation, severity of pain, severity of lameness, and appetite were scored before and periodically for up to 40 hours after surgery.
Cats treated with a TFP had better recovery scores at 2 of 4 evaluation times, lower sedation scores at 2 of 8 evaluation times, and lower pain scores at 6 of 8 evaluation times, compared with cats treated with butorphanol. Use of a pressure-sensitive mat to evaluate force applied by the forelimbs did not reveal any differences between groups but did reveal a significant difference between preoperative and postoperative values. Mean +/- SD serum fentanyl concentrations were 1.56 +/- 1.08, 4.85 +/- 2.38, 4.87 +/- 1.56, and 4.35 +/- 2.97 ng/ml approximately 8, 24, 32, and 48 hours, respectively, after TFP placement.
Results suggest that use of a TFP (25 micrograms/h) for postoperative analgesia in cats undergoing onychectomy with or without surgical sterilization is safe and effective.
To compare postoperative signs of discomfort and complications associated with use of CO2 laser for onychectomy with those of the scalpel technique in cats.
Prospective, randomized, masked clinical trial.
20 client-owned cats.
Forelimb feet (right, left) were randomly assigned to laser and scalpel treatment groups. Signs of discomfort (lameness and signs of pain) and complications (hemorrhage, swelling, and discharge) were assessed on days 0, 1, and 7. Surgeries were performed by 1 experienced surgeon. Evaluations were performed by 2 individuals without knowledge of treatment group. Signs of discomfort and complications were scored on scales of 0 to 8 and 0 to 9, respectively.
Onychectomy did not result in high discomfort or complication scores 1 day after surgery, regardless of technique used, although the laser-treated group had significantly lower scores for signs of discomfort and complications. Seven days after surgery, significant differences were not detected between groups for signs of discomfort or complications.
The CO2 laser can be an excellent tool for onychectomy in cats, with excellent hemostasis and minimal postoperative discomfort and complications. Differences in discomfort and complications between groups treated via scalpel versus CO2 laser were not clinically relevant and were only observed 1 day after surgery.
To compare postoperative discomfort assessed by subjective pain score and plasma cortisol concentrations in cats undergoing onychectomy that received analgesia by use of transdermal fentanyl (TDF) patches or an i.m. injection of butorphanol.
Randomized prospective clinical trial.
22 client-owned cats weighing 2.2 to 5 kg (4.84 to 11 lb) undergoing onychectomy.
Researchers were blinded to which cats received a TDF patch (25 microg/h) 18 to 24 hours prior to surgery or an i.m. injection of butorphanol (0.2 mg/kg (0.09 mg/lb]) at the time of sedation, immediately following extubation, and at 4-hour intervals thereafter for 12 hours. Clinical variables, plasma cortisol concentration, and pain scores were evaluated and recorded 24 hours prior to surgery, at extubation, and 2, 4, 8, 12, 24, 36, and 48 hours after surgery.
The TDF group had a lower pain score than the butorphanol group only at 8 hours after surgery. Both groups had significantly lower mean plasma cortisol concentrations 0, 24, 36, and 48 hours after surgery, compared with mean plasma cortisol concentrations prior to surgery. No significant differences in appetite or response to handling the feet were observed between the 2 groups.
Our data did not reveal a difference in pain relief between administration of TDF and butorphanol. Plasma cortisol concentrations were not different between groups. Fentanyl appeared to provide equivalent analgesia to butorphanol in cats undergoing onychectomy. The primary advantage of using a TDF patch is that repeated injections are not required.
In this prospective, randomized, blinded study, 68 clinically healthy cats that had onychectomy (n = 20), onychectomy and castration (n = 20), or onychectomy and ovariohysterectomy (n = 28) were randomly assigned to one of four postoperative analgesic treatment groups: buprenorphine (0.01 mg/kg body weight, intramuscularly [IM]), oxymorphone hydrochloride (0.05 mg/kg body weight, IM), ketoprofen (2 mg/kg body weight, IM), and placebo (physiological saline). Sedation scores, visual analog pain scores, cumulative pain scores, serum cortisol concentration, and appetite were used to assess postoperative analgesic effect. Buprenorphine demonstrated the highest efficacy with the lowest cumulative pain scores and serum cortisol levels.
To determine analgesic efficacy and adverse effects of preemptive administration of meloxicam or butorphanol in cats undergoing onychectomy or onychectomy and neutering.
Randomized controlled study.
64 female and 74 male cats that were 4 to 192 months old and weighed 1.09 to 705 kg (2.4 to 15.5 lb).
Cats received meloxicam (0.3 mg/kg [0.14 mg/lb], s.c.) or butorphanol (0.4 mg/kg [0.18 mg/lb], s.c.) 15 minutes after premedication and prior to anesthesia. A single blinded observer measured physiologic variables, assigned analgesia and lameness scores, and withdrew blood samples for each cat at baseline and throughout the 24 hours after surgery. Rescue analgesia (butorphanol, 0.4 mg/kg, i.v. or s.c.) or administration of acepromazine (0.025 to 0.05 mg/kg [0.011 to 0.023 mg/lb], i.v.) was allowed.
Meloxicam-treated cats were less lame and had lower pain scores. Cortisol concentration was higher at extubation and lower at 1, 5, and 12 hours in the meloxicam-treated cats. Fewer meloxicam-treated cats required rescue analgesia at 3, 5, 12, and 24 hours after extubation. General impression scores were excellent or good in 75% of meloxicam-treated cats and 44% of butorphanol-treated cats. There was no treatment effect on buccal bleeding time; PCV and BUN concentration decreased in both groups, and glucose concentration decreased in meloxicam-treated cats.
Preoperative administration of meloxicam improved analgesia for 24 hours without clinically relevant adverse effects in cats that underwent onychectomy or onychectomy and neutering and provided safe, extended analgesia, compared with butorphanol.
Elective ovariohysterectomy was performed on 66 cats. Surgical approach was flank (group F) or midline (group M) allocated by block randomisation. Pre-anaesthetic medication was acepromazine (0.1 mg/kg) via intramuscular injection. Anaesthesia was induced with intravenous thiopentone, and maintained with halothane in 100% oxygen. Carprofen (4 mg/kg) was administered by the subcutaneous route immediately after induction of anaesthesia. Postoperative pain and wound tenderness were assessed at 1, 3, 6, 9, 11-12 and 20-24h after the end of surgery, and the assessment outcome marked on visual analogue scales (VAS). Intervention analgesia (if pain VAS was >40 mm) was pethidine 4 mg/kg via intramuscular injection. Area under the curve (AUC) for VAS for pain and VAS for wound tenderness for each cat were calculated. AUC for wound tenderness was significantly greater for group F (P = 0.007). There was no significant difference for AUC for pain between the groups. In conclusion, wounds after flank ovariohysterectomy are significantly more tender than after midline ovariohysterectomy in the cat. This indicates that interactive methods, including wound palpation, must be used to assess postoperative pain and the findings should be appropriately weighted in the overall assessment.
To evaluate signs of postoperative pain and complications after forelimb onychectomy in cats receiving buprenorphine alone or with bupivacaine administered as a 4-point regional nerve block.
Prospective, randomized, double-blind clinical trial.
20 cats.
All cats received buprenorphine (0.01 mg/kg [0.004 mg/lb], IM) preoperatively. One forelimb of each cat also received bupivacaine (1 mg/kg [0.45 mg/lb] of a 0.75% solution) administered as a 4-point regional nerve block. After onychectomy, discomfort (lameness, foot reaction, and pain) scores were evaluated by 2 experienced observers 2, 4, 6, 8, 24, and 168 hours postoperatively. Complication (hemorrhage, swelling, and infection) scores were evaluated 24 and 168 hours postoperatively. Surgeries were performed by 1 experienced veterinary surgeon. Rescue analgesia was provided if needed.
6 cats required rescue analgesia postoperatively. There was no difference in discomfort or complication scores between control limbs and limbs in which a nerve block was administered. Additionally, there was no difference in discomfort and complication scores between cats that did or did not require rescue analgesia.
Bupivacaine administered as a 4-point regional nerve block in addition to a systemic analgesic did not decrease discomfort or complication scores in cats undergoing forelimb onychectomy.
To evaluate short-term postoperative forelimb function after scalpel and laser onychectomy in cats.
Randomized, prospective study.
20 healthy adult cats.
Cats were randomly assigned to the laser (n = 10) or scalpel (10) onychectomy group. Unilateral left forelimb onychectomy was performed. In the scalpel group, a tourniquet was used during surgery and a bandage was applied after surgery. Pressure platform gait analysis was performed prior to and 1, 2, 3, and 12 days after onychectomy. Peak vertical force (PVF), vertical impulse, and the ratio of the PVF of the left forelimb to the sum of the remaining limbs (PVF ratio) were used as outcome measures.
The laser onychectomy group had significantly higher ground reaction forces on days 1 and 2 and significantly higher PVF ratio on day 12, compared with the scalpel group. Similarly, significant differences were found in change in ground reaction forces on days 1 and 2 and the PVF ratio on day 12, compared with day -1. No cats required rescue analgesia during the course of the study. One cat in the laser group had signs of depression and was reluctant to walk on day 2 after surgery, had physical examination findings consistent with cardiac insufficiency, and was euthanized.
Cats had improved limb function immediately after unilateral laser onychectomy, compared with onychectomy with a scalpel, tourniquet, and bandage. This improved limb function may result from decreased pain during the 48 hours following unilateral laser onychectomy.
Evidence-based medicine (EBM) is the combination of the best available research evidence with clinical experience and patient needs. The concept of EBM as a part of clinical decision making has become increasingly popular over the last decade. In the hierarchy of studies meta-analysis and systematic reviews occupy the highest levels. A systematic review of a clinical question can be performed by following a relatively standard form. These techniques as described here can be performed without formal training. Systematic reviews conducted in this fashion can be used as a higher form of current concepts or as review articles and replace the traditional expert opinion narrative review.
To document the power and required sample sizes to achieve certain treatment objectives in the veterinary analgesia literature.
Pubmed's MEDLINE database and selected journals were searched. Only publications produced between 1994 and 2004 that reported 'no difference' between experimental groups in the abstract, results or conclusion sections and those that were randomised, prospective and blinded were reviewed. The data reported in the publications were then subjected to power analyses to determine the power and necessary sample size (to achieve a power of 0.8) to allow detection of 20 per cent, 50 per cent and 80 per cent treatment effects.
Twenty-two studies provided sufficient data for analysis. Five out of 22 (23 per cent) had sufficient power to detect a 20 per cent treatment effect, 12 of 22 (54 per cent) had sufficient power to detect a 50 per cent treatment effect and 18 of 22 (82 per cent) had sufficient power to detect an 80 per cent treatment effect. The mean number of animals required per group to document a 20 per cent, 50 per cent and 80 per cent treatment effect were 90, 15 and 7, respectively.
Publications that report no significant difference between analgesic regimens may have committed a Type II error. The reader may inappropriately conclude that there is no difference between treatments when there may, in fact, be a superior analgesic regimen. Clinical practice based on the principles of evidence-based medicine could therefore result in suboptimal care for patients.
The 2011 Oxford Levels of Evidence (Introductory Document). <http://www.cebm.net/ocebm-levels-of-evidence/> (accessed 17 September 2015)
- Howick J
- Chalmers I
- Glasziou P