open access

Article Links


PICO question

In female dogs undergoing elective neutering via midline coeliotomy is ovariectomy superior to ovariohysterectomy in terms of anaesthetic duration, incision length, complications and postoperative pain?

Clinical bottom line

Category of research question


The number and type of study designs reviewed

The number and type of study designs that were critically appraised were four prospective clinical trials (Peeters et al., 2011; Lee at al., 2013; Harris et al., 2013; and Tallant et al., 2016) and a retrospective cohort study (Okkens et al., 1997)

Strength of evidence

Critical appraisal of the selected papers meeting the inclusion criteria collectively provide weak evidence in terms of their experimental design and implementation

Outcomes reported

Okkens et al. (1997) found no occurrence of pyometra/endometritis in 135 dogs receiving ovariectomy (OVE) or ovariohysterectomy (OVH) over an 8–11 year follow-up period. This study also reported no significant difference in long-term postoperative complications in either group.

Of the four prospective clinical trials one (Harris et al., 2013) had final year vet students perform the surgeries. This study found no difference in incision length, surgical time or incidence of intra-operative complications between techniques. However the relevance of this study to procedures performed by qualified veterinary surgeons is questionable.

The remaining papers all evaluated incision length, surgical time and postoperative pain after surgeries performed by experienced vets. All three found mean incision length was shorter in the OVE group and two (Lee et al., 2013; and Tallant et al., 2016) found that surgical duration was shorter in the OVE group. Only one paper (Lee et al., 2013) revealed a significant difference in pain scoring between groups, with the OVE group having lower scores at 1, 2, 4 and 6 hours post-surgery. Lee at al. (2013) and Tallant et al. (2016) also recorded intra-operative complications, however none were noted in either group


In view of the strength of evidence and the outcomes from the studies the following conclusion is made; whilst the evidence does suggest OVE may be associated with some modest improvement in surgical time and incision length, due to the small sample sizes and varying techniques used, further studies are required before definitive conclusions can be made.

There is currently insufficient evidence to determine if there is a difference in complication rates or postoperative pain between procedures.


How to apply this evidence in practice

The application of evidence into practice should take into account multiple factors, not limited to: individual clinical expertise, patient’s circumstances and owners’ values, country, location or clinic where you work, the individual case in front of you, the availability of therapies and resources.

Knowledge Summaries are a resource to help reinforce or inform decision making. They do not override the responsibility or judgement of the practitioner to do what is best for the animal in their care.


Open Access Peer Reviewed