In Cats and Dogs Does Laparoscopic Ovariectomy Offer Advantages Over Open Ovariectomy for Postoperative Recovery ?

Clinical bottom line: Available research suggests ovariectomy by laparoscopy leads to a more positive recovery following surgery, due to reduced pain and smaller reductions in activity levels postoperatively when compared to open ovariectomy. In practices where laparoscopic equipment and expertise are available, offering laparoscopic ovariectomy for routine spays of cats and dogs may be advantageous to patients.

body weight and surgical time -Tukey-Kramer test used for post-hoc analysis -Complications compared by Pearson's x 2 contingency analysis -Repeated measures ANOVA to test differences in pain scoring -Wilcoxon method for nonparametric comparisons between pairs Study design: Blinded, randomised controlled trial Outcome studied: -Pre and postoperative pain scores (1,2,3,4 hrs following extubation) using visual analogue scale (VAS), simple descriptive scale (SDS) and von Frey meter (VF) -assessors blinded to surgical group -Surgical complications (scored 0-3 on occurrence) -Surgical duration (

Postoperative pain scores (VAS, SDS and VF)
-Significantly greater VAS score in L-ECS vs. L-LigaSure, p=0.011 at time point 4 hours following extubation -No difference in VAS score seen at any other time point between the three groups -No differences seen in SDS or VF pain score between the three groups Limitations: -Pain scores were determined by two observers -blinded to treatment -this could have resulted in variation between pain scoring between individuals when using the VAS and SDS methods -A standardised incision was made for all techniques (location and length) to allow the blinding of pain scorersthis could have strongly impacted on pain scores since invasiveness and tissue damage has been shown to be associated with postoperative pain.This evidence is currently weak in the veterinary field but has been shown more strongly in human medicine -Laparoscopic technique was the less commonly used 1portal method and the study did not include a 2-portal method comparison, which may not be so relevant for practices.-No reporting of breeds and small sample sizes were used with no statistical analysis performed on whether these numbers were suitable.This makes it possible a type-II -The study investigators -including pain scorer -were not blinded to surgical method providing a large source of potential bias -The number of observers evaluating pain score postoperatively was not reported, so it is unclear whether additional variation in pain scores may have been present -All surgeries were performed with inexperienced vet seven animals experiencing moderate pain and a maximum of five animals experiencing mild pain.

Limitations:
-The study investigators -including pain assessor -were not blinded to surgical method providing a large source of potential bias in terms of pain scoring -The study did not report the laparoscopic technique used or how many surgeons were involved in performing the surgeries, so we cannot know whether variation was controlled in these areas -No reporting of confidence intervals, so precision of effect is unknown -Breed, mean ages of the groups were not reported, nor was the source of the animals so it is unclear whether groups were considered similar at the start of the trial

Statistical analysis
-Repeated-measures analysis of variance for effects of surgical procedure, time and interaction between the two -Bonferroni-adjusted post-tests for each group to baseline if indicated by significant F test (ratio of two variances) -Spearman's correlation coefficient for relationship between serum IL-6 and cortisol Study design: Non-randomised controlled trial Outcome studied: -Blood markers of systemic stress and surgical stress -Postoperative pain at 2, 4, 6, 12, 18, 24, 36, 48, 72 hours following surgery using a pain scale -Nociceptive threshold using cuff placed around abdominal cavity (used to interpret abdominal pain) using a previously -No direct statistical comparison of pain scores, rectal temperature or surgical duration was reported for the laparoscopic ovariectomy and open surgery groups so differences can only be tentatively suggested -No reporting of confidence intervals, so precision of effect is unknown -Two major sources of bias within the study result from no random assignment of animals to surgical groups and the subjective nature of pain scoring performed by two assessors -Unclear if pain assessors were blinded -therefore means a large source of bias is possible -No reporting of number of surgeons involved with surgeries across both groups so it cannot be determined if variation was controlled in this aspect -Type of pain scale used was not reported making it difficult to compare results to those of other studies -As two populations of animals were used and mean ages of groups not reported, the groups may not have been similar at the start of the trial

Appraisal, application and reflection
There are a number of major constraints in evaluating the evidence from these studies to accurately draw a conclusion to the original question, including the variety of recovery outcomes measured, the subjective nature of interpreting animals behaviours for pain scoring, lack of blinded pain assessors in four of the five studies, as well as varying different methods and scales used to assess pain.
There is much variation in surgical duration of the laparoscopic procedures across the studies -this is difficult to accurately evaluate due to the different laparoscopic techniques used.The experience of the surgeon must also be taken into consideration, as their experiences and confidence is expected to heavily impact on the success of the surgery.When compared to open techniques, surgical duration was longer for laparoscopic procedures across the majority of studies, however this was not always significant, and associations to recovery cannot be drawn.While results of studies measuring surgical complications (Coisman et al.) and degree of haemorrhage (Culp et al.) cannot be linked directly to recovery success, these results may offer advantages postoperatively.Complications were significantly more frequent in only one of the laparoscopic groups in the study by Coisman et al., and this is most likely to be attributable to the vessel sealing method used rather than surgical technique.Culp et al. reported fewer dogs experienced haemorrhage during laparoscopic surgery, which is a positive aspect of this technique that is valuable to mention, but further studies are needed to validate this result and to assess impact on recovery.
Pain scales are not inclusive of all variables, so different factors relating to pain may be overlooked, depending on the pain scoring method used.The large variability in the recording of pain is a major limitation to how accurately results of these studies can be compared.This highlights the need for greater use of objective pain scoring methods and consistency of pain scoring tools in order to assess pain levels and drawing conclusions between different studies.
Four out of the five studies suggest laparoscopic techniques are associated with reduced postoperative pain and less reduced activity levels.However in these four studies, the investigators assessing pain were not blinded to treatment, which is a large source for bias that ultimately limits the conclusions that can be drawn.Blinding to surgical treatment could have been possible using a large abdominal plaster or bandage to conceal the surgical incision length, and this highlights the need for a fully blinded study to be conducted to provide a stronger level of evidence.
From the studies available, the two which offer the strongest level of evidence are Culp et al., 2009 andGautier et al., 2015.Both randomly assigned animals to surgical groups using computer generated or statistical methods, and sample sizes were appropriate for analysis.Both studies reported characteristics of surgical groups and the number of surgeons carrying out surgeries, and used a consistent, standard anaesthetic protocol for all groups within each study as well as the commonly described 2-portal laparoscopic method.Both studies reported significant and substantial beneficial treatment effects of laparoscopic surgery compared to open surgery.
The only study which did not report postoperative recovery advantages following laparoscopic ovariectomy vs. open ovariectomy was Coisman et al., 2013.This was also the only study using a standardised incision site and length for all techniques studied.While this meant observers could be blinded to the surgical intervention, this may have impacted on postoperative pain scores.Some studies have shown associations between pain, surgical invasiveness and tissue damage, however the evidence is weak, so this can only be speculated but is a factor readers must take into consideration when interpreting results of this study.between laparoscopic and open surgeries, it is valuable to include these results, as pain scores were lower in animals undergoing laparoscopic techniques.These results are in line with other studies included in this summary, but they must be considered with more caution.
While the evidence suggests laparoscopic techniques can lead to a better recovery, the lack of a blinded trial to evaluate the different techniques is ultimately a major constraint to drawing a definitive clinical bottom line and is required to validate this conclusion from the current evidence available.Reduced pain and smaller reductions in activity levels have been attributed to the less invasive nature of laparoscopic techniques, due to the shorter surgical incisions, reduced tissue damage and less organ handling.Reduced haemorrhage risk is a further advantage that may be beneficial to postoperative recovery, whereas surgical duration does not seem to be associated with recovery parameters.Duration is highly variable between studies -this is likely due to the laparoscopic method used and experience of the surgeon.Further benefits of laparoscopic surgery also suggested include reduction in materials required, such as suturing material, anaesthetic volume and postoperative analgesia.
Finally, it is important to consider a number of factors when adopting laparoscopic ovariectomy including carbon dioxide insufflation risks associated with laparoscopic techniques, the cost of equipment and surgical training and whether these factors result in additional costs for clients.

Search Strategy
Databases searched and dates covered: The NOTES technique involves passing an endoscope through a natural orifice and then through an internal incision within an organ to reach the desired location in a body cavity.

Excluded -Duplicates
Excluded -Not English start of skin incision through to time of skin closure) Main findings: (relevant to PICO question): Surgical duration -Significantly longer in L-ECS group (71 minutes; p<0.001) than L-Ligasure (25.5 minutes) and open (17 minutes) groups -No difference between L-Ligasure and and open groups Surgical complications -More frequent in L-ECS group than L-Ligasure (p=0.049) and open groups (p=0.008)-No difference was seen between L-Ligasure and open groups

Freeman ( 2010 )Population:
Female dogs both research and shelter animals Sample size: N=30 -research animals (n=10) -shelter animals (n=20) Intervention details: Intervention groups -Ovariectomy performed by natural orifice transluminal endoscopic surgery (NOTES) using a transgastric approach (n=9 or 10).This technique involved passing an endoscope through the mouth into the stomach and through an incision in the gastric wall into the abdominal cavity -2-portal laparoscopic ovariectomy (n=10) -Open ovariectomy (n=10) Inclusion criteria -Healthy, females Group characteristics -Mean body weight (kg): NOTES, 21.7±10.5;laparoscopic, 18.8±4.4;open, 20.4±3.8 -No significant differences between groups relevant papers when duplicates removed Five parameters are evaluated through behaviour and response to give an overall rating of pain between 0-18 (D Holopherne-Doran et al 2010, Mahler and Reece 2007).The assessors were not blinded to surgical group -Number of additional morphine boluses given postoperatively -Quality and duration of recovery -Surgical duration (first skin incision through to last suture) Veterinary Evidence ISSN:2396-9776 Vol 2, Issue 2 DOI: http://dx.doi.org/10.18849/ve.v2i2.59 next review date: 22 Jun 2019 p a g e | 6 total pages: 14 in dogs and cats.Subjective quality and duration of recovery -No differences were seen between the three groups Pain scores -Significantly lower in animals following laparoscopic ovariectomy vs. open midline (p<0.001) and open flank techniques (p=0.016)-In the laparoscopic group, no animals experienced severe pain following surgery at any time point, however following open midline surgery this was recorded in 5% of animals 2, 4 and 6 hours postoperatively and in 5-20% of animals following open flank surgery at varying time points -Weak pain was experienced by 50% of animals 1 hour following laparoscopic surgery and increased to 95% at 12 hours; the remainder having experienced moderate pain.-Following open midline surgery, weak pain was experienced in 50% of animals 1 and 12 hours postoperatively with the remainder having experienced moderate or severe pain

7 total pages: 14 students
assisting the surgeon which could have impacted on surgical duration, especially in the laparoscopic surgeries due to unfamiliarity with the endoscope tool -No reporting of confidence intervals, so precision of effect is unknown -Breeds were not reported, so it is unclear how this relates to in practice Veterinary Evidence ISSN:2396-9776 Vol 2, Issue 2 DOI: http://dx.doi.org/10.18849/ve.v2i2.59 next review date: 22 Jun 2019 p a g e |

(relevant to PICO question):
mild, moderate or severe pain at all time points following surgery, with two animals experiencing severe pain, up to Veterinary Evidence ISSN:2396-9776 Vol 2, Issue 2 DOI: http://dx.doi.org/10.18849/ve.v2i2.59 next review date: 22 Jun 2019 p a g e | 8 total pages: 14 Freeman et al., 2010primarily investigated the NOTES technique (using a transgastric approach) vs. a 2-portal laparoscopic and open ovariectomy methods.While limited direct statistical comparisons were reported http://dx.doi.org/10.18849/ve.v2i2.59 next review date: 22 Jun 2019 p a g e | 11 total pages: 14 Abstracts 1973 to 2016 Week 22 Exclusion: Studies were excluded if they did not investigate the two ovariectomy methods relevant to the clinical question.These included studies comparing open ovariohysterectomy vs laparoscopic ovariectomy or comparison of different laparoscopic ovariectomy techniques only.Papers were also excluded if the study populations were those other than domestic dogs or cats, or, if parameters and outcomes were not linked to patient pain or recovery.Inclusion: Papers were included if the studies compared open ovariectomy and laparoscopic ovariectomy techniques.All laparoscopic methods (1-, 2-and 3-portal access and natural orifice transluminal endoscopic surgery (NOTES) techniques) were included, as were different laparoscopic instruments and vesselsealing technologies and methods.Only those studies measuring intra-and postoperative parameters linked to recovery and pain outcomes in domestic dogs and cats were considered.