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Debridement versus superficial keratectomy for indolent ulcers in dogs

Clinical Scenario

A well-known client of your practice, Mrs Reid, brings Sonny, their 6 year old male neutered Boxer to the clinic with a recurrent history of squinting in his right eye.  He was prescribed treatment for a corneal ulcer a few weeks ago, and upon examination with fluorescein stain, it appears not to have healed.  You suspect Sonny has an indolent ulcer.  You immediately go and speak with another vet in the practice who you know has recently been on an ophthalmology CPD course.  They said the specialist taking the course recommended superficial keratectomy for such cases.  You’ve never performed one of these and usually treat these cases with debridement using a sterile swab under local anaesthesia.  You know that Mrs Reid may not have the funds to be able to refer the dog to a specialist ophthalmologist.  You wonder whether the superficial keratectomy would result in a faster healing time...

3-Part Question (PICO)

In [dogs with indolent ulcers] does [debridement with a swab compared to superficial keratectomy] result in [shorter healing times]?

Search Strategy and Summary of Evidence

Search Strategy

MEDLINE(R) In-Process & Other Non-Indexed Citations and MEDLINE(R) 1946 to Present using the OVID interface

(dog.mp. OR dogs.mp. OR canine.mp. OR canines.mp. OR canis.mp. OR exp dogs/)

AND

(superficial ulcer$.mp. OR superficial erosion$.mp. OR corneal ulcer$.mp. OR corneal erosion$.mp. OR recurrent ulcer$.mp. OR recurrent erosion$.mp. OR epithelial ulcer$.mp. OR epithelial erosion$.mp. OR indolent ulcer$.mp. OR indolent erosion$.mp. OR boxer ulcer$.mp. OR boxer erosion$.mp. OR keratitis.mp. OR CSK.mp. OR epithelial basement membrane disease.mp. OR epithelial basement membrane dystrophy.mp. OR EBMD.mp. OR epithelial basement membrane ulcer$.mp. OR corneal epithelial defect$.mp. OR SCCED.mp. OR SCCEDs.mp. OR exp Keratitis/ OR exp Corneal Ulcer/)

AND

(debride$.mp. OR corneal debride$.mp. OR superficial keratectomy.mp.OR exp debridement/)

CAB Abstracts 1910 to Present using the OVID interface

(dog.mp. OR dogs.mp. OR canine.mp. OR canines.mp. OR canis.mp. OR exp dogs/)

AND

(superficial ulcer$.mp. OR superficial erosion$.mp. OR corneal ulcer$.mp. OR corneal erosion$.mp. OR recurrent ulcer$.mp. OR recurrent erosion$.mp. OR epithelial ulcer$.mp. OR epithelial erosion$.mp. OR indolent ulcer$.mp. OR indolent erosion$.mp. OR boxer ulcer$.mp. OR boxer erosion$.mp. OR keratitis.mp. OR CSK.mp. OR epithelial basement membrane disease.mp. OR epithelial basement membrane dystrophy.mp. OR EBMD.mp. OR epithelial basement membrane ulcer$.mp. OR corneal epithelial defect$.mp. OR SCCED.mp. OR SCCEDs.mp. OR exp keratitis/)

AND

(debride$.mp. OR corneal debride$.mp. OR superficial keratectomy.mp.)

Search Outcome

MEDLINE

  • 31 papers found in MEDLINE search
  • 29 papers excluded as they don't meet the PICO question
  • 0 papers excluded as they are in a foreign language
  • 2 papers excluded as they are review articles/in vitro research/conference proceedings
  • 0 total relevant papers from MEDLINE

CAB Abstracts

  • 57 papers found in CAB search
  • 50 papers excluded as they don't meet the PICO question
  • 2 papers excluded as they are in a foreign language
  • 4 papers excluded as they are review articles/in vitro research/conference proceedings
  • 1 total relevant papers from CAB

Total relevant papers

1 relevant papers from both MEDLINE and CAB Abstracts

Summary of Evidence

Stanley et al. (1998) Australia and USA (not explicitly stated)

Title:

Results of grid keratotomy, superficial keratectomy and debridement for the management of persistent corneal erosions in 92 dogs

Patient group:

Difficult to determine as not stated explicitly, but methods refer to the Animal Eye Care clinics in Australia and the USA, which are presumably referral centres

Study Type:

Retrospective case series

Outcomes:
  • 3 techniques were carried out on the patients in the study - debridement, superficial keratectomy and grid keratotomy
  • Mean time to healing of persistent corneal erosions
  • The length of time (in days) it took for healing to occur
  • Percentage healed after the procedure in each group
  • Healing was not formally defined; it is likely that this is representative of cases that no longer had evidence of loose epithelium or were negative on fluorescein stain (no retention of stain colour)
Key Results:
  • 3/19 of the debridement cases did not heal after 1-2 months of repeated debridement and were subsequently treated with superficial keratectomy (these 3 cases were analysed as part of the superficial keratectomy group; it is presumed that these 3 cases make up the 24 cases cited in the results for the superficial keratectomy group)
  • 24/24 of the superficial keratectomy cases healed after one treatment; 10/16 of the debridement cases healed after one treatment
  • The median time to healing was 21.5 days in the debridement group, and 7 days in the superficial keratectomy group
  • An ANOVA analysis determined that debridement resulted in significantly longer healing times than superficial keratectomy (P = 0.001; although the debridement group data was highlighted as not normally distributed, so the assumption of normality may not have been met for this analysis)
Study Weaknesses:
  • There were no statistical methods described in the methods section, or significance level stated prior to reporting the results
  • There was no justification of the sample size used in the study, or over what period of time the cases had been collected
  • It was not stated whether ethical approval had been sought for the study
  • There were few cases in the debridement group compared to the other groups
  • The study design (retrospective case series) is likely to be affected by substantial bias
  • The statistical test applied (ANOVA) may not have been the most suitable test for the type of data that was collected in the study
  • As it is likely that the hospitals involved were referral clinics, an element of referral bias in relation to caseload is likely
  • Cases were rechecked at different rates (Animal Eye Care Australia 7-10 days; Animal Eye Care USA 10-14 days)
  • As cases were not checked on a daily basis, mean and median healing times are dependent on when animals were rechecked (somewhere between 7 and 14 days across the different clinics)
Attachment:
No attachments.

Comments

The animals in the superficial keratectomy group also had a third eyelid flap technique performed - this is likely to have an effect on the outcomes in relation to healing.
Surgeon familiarity with the superficial keratectomy technique, and access to the appropriate equipment such as an operating microscope, are important considerations here.

Bottom line

It is likely that debridement results in longer healing times than the superficial keratectomy approach in dogs with indolent ulcers, although caution should be applied in the interpretation of the research due to the type of study conducted.  Further controlled trials are required to add confidence to the evidence base.

Disclaimer

The BETs on this website are a summary of the evidence found on a topic and are not clinical guidelines. It is the responsibility of the individual veterinary surgeon to ensure appropriate decisions are made based on the specific circumstances of patients under their care, taking into account other factors such as local licensing regulations. Read small print

References

Stanley RG, Hardman C, Johnson, BW, (1998). Results of grid keratotomy, superficial keratectomy and debridement for the management of persistent corneal erosions in 92 dogs. Veterinary Ophthalmology 1: 233-38.

About this BET

First author:
Marnie Brennan
Second author:
Natalie Robinson
Institution:

The University of Nottingham

Search last performed:
2015-10-26 14:47:36
Original publication date:
2015-10-28 14:47:36
Last updated:
2015-10-28 14:47:36
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