“New” Declaw Technique Shot Down by Facts

In January 2018, the Journal of the American Veterinary Medical Association published a letter from Dr. Kerry Yoon of Hawaii, who claims to have invented a “new, painless” declaw procedure. He is so confident that his special technique is “painless” that he has NEVER given any pain meds to the hundreds of cats and kittens he has mutilated. I’m sure many humane-minded veterinarians wrote in to complain, but JAVMA chose only two letters of opposition to publish. I am pleased that mine was one of them. Both letters are presented here (at least until AVMA makes us take them down.
Letters to the Editor
Alternative to declawing is just more of the same

I am shocked that JAVMA would print the letter from Dr. Kerry Yoon describing his alternative approach to declawing. (1) In performing this procedure, Dr. Yoon uses a nail trimmer and purposely leaves a fragment of the distal phalanx in place. Thus, the only real difference between his method and the one rst described in 1952 (2) is that he uses an electrocautery unit to destroy any germinal cells that might remain, which he claims prevents claw regrowth. However, because germinal cells are not visible to the naked eye, there is no way to tell whether the goal of destroying these cells is accomplished. Notably, a 2014 study (3) found that claw regrowth was more common with the use of a guillotine (nail clipper) technique for onychectomy than with the use of a scalpel or laser technique, although the guillotine technique in that study did not include electrocauterization of the germinal cells.

Even if claw regrowth does not occur, leaving a fragment of the distal phalanx in place seems likely to cause pain, lameness, and other complications. In a 2016 study, Gerard et al (4) concludedthat their results “supported the hypothesis that onychectomy is associated with an increase in house soiling behavior of cats.”

Similarly, a retrospective cohort study (5) involving 137 declawed and 137 nondeclawed cats found radiographic evidence of retained distal phalanx fragments in 63% (86/137) of the declawed cats, and declawed cats had higher odds of back pain, undesirable elimination habits, and aggression if they had retained distal phalanx fragments than if they did not. In addition, declawed cats had higher odds of biting and undesirable elimination habits than did nondeclawed control cats.

Dr. Yoon reports in his letter that postoperative complications have been rare following use of his technique. However, “absence of evidence is not evidence of absence,” as the saying goes, and it is not clear whether complications would have been reported by the cats’ owners or even identified. For example, bilateral lameness may not be recognized by clients, and cats, because of their known stoicism, may be in pain without showing noticeable signs.

I do not believe that JAVMA should have published
a description of this technique without any scientific study of its short- and long-term consequences. Dr. Yoon boasts that his technique is painless, but that claim and the claim that the procedure does not affect gait can, I believe, be dismissed out of hand.

The AVMA has condemned the declawing of captive exotic and wild indigenous cats because of concerns that the pain and suffering associated with declawing may be exacerbated in these populations (6) and has also stated that “pain management is necessary (not elective) and required” for declawing of domestic cats,(7) implying that the procedure causes pain and suffering in domestic cats also. The JAVMA editors should be ashamed to publish a letter that will likely result in even more cats suffering.

Jean Hofve, DVM Denver, Colorado
1. Yoon K. A different approach to declawing (lett). J Am Vet Med Assoc 2018;252:166.
2. Misener AG. Removal of claws in the domestic cat. J Am Vet Med Assoc 1952;121:390.
3. Clark K, Bailey T, Rist P, et al. Comparison of 3 methods of onychectomy. Can Vet J 2014;55:255–262.
4. Gerard AF, Larson M, Baldwin CJ. Telephone survey to investigate relationships between onychectomy or onychectomy technique and house soiling in cats. J Am Vet Med Assoc 2016;249:638–642.
5. Martell-Moran NK, Solano M, Townsend HGG. Pain and adverse behavior in declawed cats [published online ahead of print May 1, 2017]. J Feline Med Surg doi: 10.1177/1098612X17705044.
6. AVMA now condemns declawing wild and exotic cats. J Am Vet Med Assoc 2013;242:133.
7. AVMA. Declawing of domestic cats. Available at: www.avma.org/KB/ Policies/Pages/Declawing-of- Domestic-Cats.aspx. Accessed Jan 31, 2018.


Report on alternative declawing method lacks detail
In response to Dr. Kerry Yoon’s recent letter(1) describing his alternative method for declawing domestic cats, I have several questions and concerns.

First, Dr. Yoon suggests that his method preserves the connection of the exor tendon (ie, the tendon of the deep digital exor muscle) to the distal phalanx, “allowing the cat to maintain a normal stance.” However, there is no mention of integrity of the extensor tendon (ie, the tendon
of the common digital extensor muscle). Maintaining the flexor tendon with no counteracting extensor tendon can be detrimental to the function of the digit and, in my experience, can lead to contracture of the flexor tendon later in life.
Second, the description of the postoperative care indicates that cats are “discharged the same day without any evidence of limping.” This needs clarification, as it suggests that analgesia is not routinely provided and that a lack of lameness is being used as the marker for a lack of pain. This procedure should never be performed without adequate postoperative analgesia. There have been many advances in identifying pain in cats over the past 5 years that involve evaluating them for more than lameness.(2)

Third, it is uncertain whether the method described would end all horn-generating epidermal activity. I have performed approximately 100 declaw revision procedures in the past 4 years to remove small and large remnants of the distal phalanx. Most fragments that still had active horn- generating epidermis also had abnormal tissue below the skin that was not externally visible. Further, the tissues that form the many components of the nail in cats originate from several locations, and I am skeptical that blindly cauterizing the phalanx is an effective method for preventing subsequent horn-generating activity. The external coronary horn originates from dermis that lines the internal surface of the ossi ed unguicular hood,(3) which is located close to the extensor process of the distal phalanx, and would be difficult, if not impossible in my opinion, to reach with electrocautery alone. By contrast, the sole horn originates from dermis on the palmar aspect of the unguicular process.(3) Other nail components originate from separate sites.

Finally, as with other partial amputation methods, there appears to have been little consideration of the potential for disruption of the growth plate of the distal phalanx. To my knowledge, there is no published research about the effects of distal phalangeal growth plate disruption in cats, but this theoretically has the potential to result in abnormal bone growth or a lack of bone growth.

I do not support the declawing of cats, even with this method. The reported results are anecdotal, with no verifiable data, and demonstrate the veterinary field’s need for further research into the pathological consequences of declawing cats, no matter the method.
Nicole K. Martell-Moran, DVM, MPH, Feline Medical Center
Houston, Texas
1. Yoon K. A different approach to declawing (lett). J Am Vet Med Assoc 2018;252:166.
2. Epstein ME, Rodan I, Griffenhagen G, et al. 2015 AAHA/AAFP pain management guidelines for dogs and cats. J Feline Med Surg 2015;17:251–272.
3. Homberger DG, Ham K, Ogunbakin T, et al. The structure of the cornified claw sheath in the domesticated cat (Felis catus): implications for the claw-shedding mechanism and the evolution of cornified digital end organs. J Anat 2009;214:620–643.

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