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Midline versus flank approach and pain in neutering of cats

Clinical Scenario

Dr Perry brings her 5 month old female domestic shorthair kitten, Kylie, in to be spayed. She has read on the internet that cats can be spayed midline or via the flank. She is very concerned about Kylie being in pain and asks you which is the least painful surgical option for Kylie. You wonder if one is less painful than the other...

3-Part Question (PICO)

In [female cats that are being neutered] does [a midline approach compared to a flank approach] [decrease pain following surgery]?

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

(cat.mp. OR cats.mp. OR feline.mp. OR felines.mp. OR queen.mp. OR queens.mp. OR felis.mp. OR felidae.mp. OR exp Cats/ OR exp Felis/ OR exp Felidae/)

AND

(spey.mp. OR speyed.mp. OR speying.mp. OR spay.mp. OR spayed.mp. OR spaying.mp. OR neuter.mp. OR neutered.mp. OR neutering.mp. OR ovariectomy.mp. OR ovariohysterectomy.mp. OR hysterectomy.mp. OR sterilised.mp. OR sterilized.mp. OR sterilisation.mp. OR sterilization.mp. OR de-sex.mp. OR de-sexed.mp. OR de-sexing.mp. OR desex.mp. OR desexed.mp. OR desexing.mp. OR gonadectomy.mp. OR exp Ovariectomy/ OR exp Sterilization, Reproductive/ OR exp Hysterectomy/)

AND

(midline.mp. OR flank.mp. OR linea alba.mp. OR laparotomy.mp. OR coeliotomy.mp. OR celiotomy.mp. OR lateral approach.mp. OR exp Laparotomy/)

CAB Abstracts 1910 to Present using the OVID interface

(cat.mp. OR cats.mp. OR feline.mp. OR felines.mp. OR queen.mp. OR queens.mp. OR felis.mp. OR felidae.mp. OR exp cats/ OR exp Felis/ OR exp Felidae/)

AND

(spey.mp. OR speyed.mp. OR speying.mp. OR spay.mp. OR spayed.mp. OR spaying.mp. OR neuter.mp. OR neutered.mp. OR neutering.mp. OR ovariectomy.mp. OR ovariohysterectomy.mp. OR hysterectomy.mp. OR sterilised.mp. OR sterilized.mp. OR sterilisation.mp. OR sterilization.mp. OR de-sex.mp. OR de-sexed.mp. OR de-sexing.mp. OR desex.mp. OR desexed.mp. OR desexing.mp. OR gonadectomy.mp. OR exp ovariectomy/ OR exp gonadectomy/ OR exp sterilization/ OR exp hysterectomy/)

AND

(midline.mp. OR flank.mp. OR linea alba.mp. OR laparotomy.mp. OR coeliotomy.mp. OR celiotomy.mp. OR lateral approach.mp. OR exp laparotomy/)

Search Outcome

MEDLINE

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

CAB Abstracts

  • 188 papers found in CAB search
  • 175 papers excluded as they don't meet the PICO question
  • 0 papers excluded as they are in a foreign language
  • 8 papers excluded as they are review articles/in vitro research/conference proceedings
  • 5 total relevant papers from CAB

Total relevant papers

5 relevant papers from both MEDLINE and CAB Abstracts

Comments

There are only four papers in the evidence summary table as Coe et al. Veterinary Record (2006) 159: 309-313 contains the same data set as Grint et al. Grint et al was selected for the BET as it was more relevant.

Summary of Evidence

Burrow et al. (2006) UK

Title:

Prospective evaluation of postoperative pain in cats undergoing ovariohysterectomy by a midline or flank approach.

Patient group:

Female cats undergoing ovariohysterectomy. 

Study Type:

Randomised controlled trial

Outcomes:
  • Pain, using a modified version of the Cambridge SDS score system
  • Pain was assessed pre-operatively and at 30 minutes, 1, 2, 4, 8, 12 and 24 hours post-operatively
  • Duration of surgery
Key Results:
  • No significant difference in post-operative pain between different approaches (p=0.05)
  • Midline approach associated with a significantly longer surgery time than flank approach (13.6 minutes versus 11.1, p=0.006).
  • Longer surgery time was significantly associated with reduced post-operative pain (p=0.01). However, midline approach and post-operative pain were NOT significantly independently correlated
  • Cats had reached their pre-operative pain score (or lower) by 24 hours post-operatively
Study Weaknesses:
  • Small study group (20 cats overall)
  • Not blinded
  • Pain score previously optimised was modified
  • Multiple statistical tests on a small data set
Attachment:
Evidence appraisalEvidence appraisal

Grint et al. (2006) UK

Title:

Assessment of the influence of surgical technique on post operative pain and wound tenderness in cats following ovariohysterectomy.

Patient group:

66 female cats undergoing ovariohysterectomy. Mostly DSH, median age 9 months for flank groups, 10.5 months for midline, mean weight 2.71kg. On pre-operative examination none were pregnant, lactating or in oestrus.

Study Type:

Randomised controlled trial

Outcomes:
  • Pain using a previously described visual analogue scale
  • Wound tenderness assessed by digital palpation and scoring on a visual analogue scale 
  • Number of cats requiring rescue analgesia
Key Results:
  • No significant difference in post-operative pain as assessed by pain scoring (mean midline pain score 324 versus 357 for flank, p=0.516)
  • Wound tenderness significantly increased in flank approaches compared to midline (Mean score flank 381 versus midline 256, p=0.007) 
  • Two cats in each group required rescue analgesia
Study Weaknesses:
  • Small number of cats (66) -- although a sample size calculation was performed and sample size was reached
  • Not blinded (attempted but cats resented having post-operative bandages on them and proved unfeasible)
  • Surgery performed by final year veterinary students with variable levels of experience and ability: the observed effect may be due to surgeon inexperience.
  • Subjectivity in the scoring of the outcomes 
Attachment:
Evidence appraisalEvidence appraisal

Oliveira et al. (2014), Brazil

Title:

Pain assessment in cats undergoing ovariohysterectomy by midline or lateral celiotomy through use of a previously validated multidimensional composite pain scale

Patient group:

14 healthy female cats up to three years old from a shelter undergoing ovariohysterectomy

Study Type:

Randomised controlled trial

Outcomes:
  • Pain (Botucatu multidimensional composite pain scale) at 1, 2, 4, and 6 hours post surgery
  • Duration of surgery
  • Number of cats needing rescue analgesia and when this was needed
Key Results:
  • No significant difference between surgical approach for each individual item of the Botacatu pain scale, or the pain expression subdivision of the scale.
  • Flank incision resulted in the higher total pain score (excluding blood pressure which was not measured) (p=0.023) and also a higher score for the psychomotor changes subdivision of the scale (p=0.047).
  • Surgery time was not significantly different. Mean times were 24.5 minutes for midline and 28.0 for flank.
  • 6 of 7 cats receiving a flank incision and 3 out of 7 cats receiving a midline incision required rescue analgesia
Study Weaknesses:
  • Anaesthesia and analgesia protocol unconventional in UK practice.
  • The pain score was modified and not revalidated.
  • Unclear if assessors were successfully blinded to which location the cat had an incision.
  • Small group size.
  • Basic data of the groups not explained.
  • Multiple statistical tests on a small data set.
  • Not clear when rescue analgesia was given.
  • Many cats required rescue analgesia.
Attachment:
Evidence appraisalEvidence appraisal

Gauthier et al. (2014)

Title:

Assessment of postoperative pain in cats after ovariectomy by laparoscopy, median celiotomy, or flank laparotomy.

Patient group:

60 healthy female DSH cats, ASA 1, none aggressive.

Study Type:

Randomised controlled trial

Outcomes:
  • Pain, using the 4A-vet pain scale
  • Assessed at 1, 2, 4, 6 and 12 hours after endotracheal extubation
  • Duration of anaesthesia, surgery and recovery
Key Results:
  • Laparoscopic ovariectomy was the least painful procedure
  • No significant difference in pain scores between the midline and flank approaches
  • Laparoscopic ovariectomy was significantly longer
Study Weaknesses:
  • Lack of a blinded investigator to measure outcomes
  • Small study group (60) - no sample size calculation
  • All procedures performed with veterinary student assistants which may have affected results, particularly surgical time
  • The 4A-Vet scale is validated in dogs but not cats

 

Attachment:
Evidence appraisalEvidence appraisal

Comments

This is an updated version of the BET originally published in September 2013 and authored by Jenny Stavisky and Marnie Brennan.

The original BET included Burrow et al (2006) and Grint et al (2006). The appraisals of these papers have been updated to include more detail; and new appraisals of Oliveira et al (2014) and Gauthier et al (2014) have been added.

All of the papers used different pain scales, some validated in cats and some are modified. These may produce different results from each other, and be of variable validity.

All pain scales involved interpretation of a cats behavioural expression of pain, which can be variable, and interpretation is subjective and requires training.

The nature of the question makes it difficult to blind the trial. It is impossible to blind the surgeon to the intervention, and very difficult to blind the assessor, which is espcially problematic as the assessment is subjective.

One paper found the flank approach to have a significantly higher pain score. The cats in this study did not receive analgesia routinely used in the UK, so this difference may not be clinically significant in UK patients.

Laparoscopic approach was found to be significantly less painful than either the midline or flank approach in cats undergoing ovariectomy. Laparoscopic ovariectomy is not routinely offered at most practices in the UK, but may be in future. The findings of no significant difference in pain score from either flank or midline incisions should be applied with care as most cats spayed in the UK currently undergo a ovariohysterectomy.

Bottom line

There is no clear evidence that a flank incision is more or less painful than a midline incision for a cat spay. Surgeon preference and individual patient circumstances should be considered when choosing which approach to take. 

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

Burrow R, Wawra E, Pinchbeck G, Senior M, Dugdale A, (2006). Prospective evaluation of postoperative pain in cats undergoing ovariohysterectomy by a midline or flank approach. Veterinary Record 158: 657-660.

Gauthier O, Holopherne-Doran D, Gendarme T, Chebroux A, Thorin C, Tainturier D, Bencharif D, (2014). Assessment of postoperative pain in cats after ovariectomy by laparoscopy, median celiotomy, or flank laparotomy. Veterinary Surgery 44: 23-30

Grint NJ, Murison PJ, Coe RJ, Waterman Pearson AE, (2006). Assessment of the influence of surgical technique on post operative pain and wound tenderness in cats following ovariohysterectomy. Journal of Feline Medicine and Surgery 8: 15-21.

Oliveira JP, Mencalha R, Sousa CA, Abidu-Figueiredo M, Jorge Sda F, (2014). Pain assessment in cats undergoing ovariohysterectomy by midline or lateral celiotomy through use of a previously validated multidimensional composite pain scale. Acta Cirurgica Brasileira 29: 633-638.

About this BET

First author:
Bree Merritt
Second author:
Abi Collinson
Institution:

University of Nottingham

Search last performed:
2017-12-19 14:45:07
Original publication date:
2017-12-19 14:45:07
Last updated:
2017-12-19 14:45:07
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