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Park et al. Mini-invasive Surg 2020;4:87 I http://dx.doi.org/10.20517/2574-1225.2020.87 Page 13 of 16

Our data demonstrated that operative time was significantly longer with the IA technique by 10 min on
weighted mean difference when compared to the EA technique. Although this was statistically significant,
large variations in operative time reported in included studies were reflected by serious heterogeneity in
2
our analysis (I = 85%). Operative time can be influenced by a multitude of factors beyond technical aspects
alone, which may include fat distribution in individual patient, adhesions from previous abdominal surgery,
extension of the tumour, and/or experience of individual surgeon to account for the learning curve effect.
Unfortunately, however, these potential confounders were not easily identifiable in the available studies.

The lower rates of surgical site infections and incisional hernia observed in the IA cohort may be chiefly
attributed to the extraction site. The IA approach allows flexibility when choosing the location of the
incision for specimen extraction. In our analysis, the most common extraction site in the IA cohort
(described explicitly in 15 studies) was through Pfannenstiel incision on the suprapubic port site, which
is well recognised to result in good cosmetic satisfaction with low morbidity, less pain, and lower rates of
[37]
incisional hernias .

The return of bowel function was faster in the IA cohort, which is consistent with the widely accepted
theory that patients undergoing IA are expected to undergo reduced manipulation of the colon and
mesentery. This notion is gaining considerable attention, especially in the era of growing obese population
among surgical patients. A totally laparoscopic approach is thought to minimise traction injuries and risk
of micro-lacerations when exteriorising the bowel through thicker abdominal walls, which is known to
worsen the outcome in bowel anastomosis [5,17] . However, the paucity in research is reflected by the fact that
[12]
only one study, Vignali et al. , 2018, was dedicated to a direct comparison between IA with EA in obese
population, which did not demonstrate significant difference between the two groups in terms of peri-
operative outcomes, except for the lower incidence of incisional hernia in the IA group. Further studies are
thus warranted to validate this notion, which would be valuable for evidence-based safe surgical practice in
an obese population.

In addition, there are two growing areas of interest for which IA could provide superior outcomes, robotic
[38]
surgery and patients undergoing emergency colectomy. A 2020 meta-analysis by Genova et al. showed
that robotic right colectomy is superior to the laparoscopic approach in terms of length of stay, time to first
flatus, and overall rate of complications. Part of this difference was attributed to the rate of IA in robotic
colectomy, which was 10 times higher than in laparoscopic colectomy, and when a subgroup analysis was
carried out for EA in both groups, the advantages of robotic colectomy disappeared, suggesting that IA may
be a strong reason for superior outcome. Di Saverio et al. recently published a case series of 59 emergent
[39]
laparoscopic colectomies with intracorporeal anastomosis, showing that such a technique is feasible
and likely safe in acute surgery. The case series demonstrated an anastomotic leak rate of 3.4% and a re-
intervention rate of 3.4%, both of which are comparable to the data found by this meta-analysis. This is a
novel area that warrants further research.

However, this analysis should not be taken at its face value as it is not without limitations on closer
inspection. In terms of the secondary outcomes, the data collected by the studies included in this meta-
analysis are overall substantially heterogeneous, making it challenging to draw robust conclusions. The lack
of standardised experimental conditions is likely to have impacted on the clinical outcome measures. For
[15]
example, Anania et al. reported that the authors did not standardise the surgical steps of extracorporeal
anastomosis in right hemicolectomy, although the intracorporal technique was uniform. Additionally,
it is unclear whether some of the peri-operative measures known to improve patient outcomes were
implemented. For example, it was unknown if the ERAS (enhanced-recovery-after-surgery) protocol, pre-
operative bowel preparation, or prophylactic antibiotics were administered.