The impact of obesity on laparoscopic liver surgery: a critical reappraisal

Laparoscopic liver surgery has been demonstrated to be a safe and efficient approach in the treatment of several hepatic lesions (1-3). Laparoscopic liver resections (LLR) are increasingly performed worldwide (4); nevertheless, their utility in patients with increased body mass index (BMI) remains ill-determined. Obesity rates escalate significantly during the last decades whereas a strong association between obesity and poor postoperative outcomes is reported (5-8). Surgical procedures in these patients are considered highly challenging due to concomitant comorbidities including diabetes, cardiovascular pathologies, non-alcoholic fatty-liver disease as well as intraoperative technical limitations (9,10). Vigano et al. showed that severe morbidity and mortality rates in obese patients undergoing open liver resection (OLR) versus non-obese were similar even in cases of major hepatectomy or underlying cirrhosis (11). On the other hand, only a limited number of studies have aimed to evaluate the safety and adequacy of LLR in this particular high-risk group (10,12,13). According to the available literature, laparoscopic hepatic resections in obese patients may be safely performed with no additional risk compared to non‐obese patients (12).

Ome et al. published their institutional experience with LLR in obese patients with regards to short-term outcomes (14); the authors’ objective was to evaluate the safety and efficacy of LLR versus OLR in obese patients as well as that of LLR in obese versus non-obese patients. Significantly reduced blood loss, fewer intraoperative transfusions, fewer positive surgical margins, and shorter postoperative hospital stay were shown in the obese LLR group compared to the obese OLR group. Additionally, when the LLR obese group versus the LLR non-obese group was compared, only operation time was found significantly protracted in obese patients. Finally, no differences were detected in morbidity or mortality between the LLR obese group and either the OLR obese or the LLR non-obese groups.

The definition of obesity in their study is a critical limitation as also acknowledged by the authors. The same limitation was also met in two previous similar studies (15,16). Their patients of Asiatic origin were considered obese with a BMI of 25 kg/m² contrary to the World Health Organization (WHO) standard of BMI of 30 kg/m² (5,6). As a result, whether the results of Ome et al. are substantially different from that of European or American studies, which comprised patients with similar BMI must be evaluated. Our group published a meta-analysis of ten European studies, which assessed results from LLR versus OLR in patients with HCC (17). Four out of 10 studies reported patient BMI for the laparoscopic and open group; the mean BMI in LLR patients ranged from 25.0 to 28.7 kg/m² whereas in the OLR group the mean BMI ranged from 24.2 to 27.5 kg/m². Our analysis consistently showed reduced blood loss, transfusion rates and hospital stay in the LLR group similar to the study by Ome et al. Additionally it should be noted that 5 out of 10 studies included studies assessing results exclusively from cirrhotic patients. Therefore, one might argue that the study by Ome et al. did not exhibit new evidence on the beneficial role of LLR in patients with a median BMI of 26.9 kg/m², thus confirmed the results of previous non-Asiatic studies, which comprised patients who were not characterized as obese.

On the other hand, the subgroup comparison between 13 (out of the 63) highly obese patients who underwent LLR (median BMI of 32.0 kg/m²; range, 30.0–33.9 kg/m²) and 16 highly obese patients who underwent OLR (median BMI of 31.1 kg/m²; range, 30.1–35.9 kg/m²) is of more interest (14). LLR in the highly obese group was associated with reduced blood loss and blood transfusion compared to the open group, whereas no differences were shown in operative time, hospital stay, complication or mortality rates. Nonetheless, the patient sample size is too small to draw safe conclusions (13 versus 16 patients).

Cauchy et al. evaluated risk factors of conversion in laparoscopic major liver resection and showed that increased BMI (>28 kg/m²) was an independent risk factor for conversion to OLR (18). An international survey of laparoscopic liver surgeons aimed to evaluate the perceived degree of difficulty of factors previously reported to affect the difficulty of LLR; increased BMI (>30 and >35 kg/m²) was found to add moderate difficulty in LLR performance (19). Hasegawa et al. recently published their proposal of a novel model for prediction of LLR surgical difficulty (20); In their multivariate analysis, obesity (BMI >30 kg/m²) was found significantly correlated with protracted operative times. Moreover, another study showed that dense abdominal wall as increased with higher BMI presents a significant limitation in the movement of trocars during laparoscopy, whereas mobilization of the liver can be difficult as a result of increased liver size (21).

Obese and morbidly obese patients represent high-risk groups that require particular management. Indeed, the number of patients included in the study by Ome et al. is the largest compared to previous similar studies and might show some utility when addressing exclusively to Asian populations (14-16). Whatsoever, generalization of the outcomes by Ome et al. must be viewed with caution, as they do not apply to obese non-Asian patient populations. Additional larger studies including patients with BMI >30 kg/m² and furthermore >35 kg/m² are needed in order to properly evaluate the impact of obesity on patients undergoing LLR versus OLR. Moreover, studies need to provide further information on the effect of tumor location on the outcomes given the fact that the body structure of obese and morbidly obese patients might constitute a technically major surgical challenge particularly in the case of LLR for lesions in posterosuperior segments.

Acknowledgments

Funding: None.

Footnote

Provenance and Peer Review: This article was commissioned by the editorial office, Laparoscopic Surgery. The article did not undergo external peer review.

Conflicts of Interest: Both authors have completed the ICMJE uniform disclosure form (available at http://dx.doi.org/10.21037/ls.2018.05.04). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Abu Hilal M, Aldrighetti L, Dagher I, et al. The Southampton Consensus Guidelines for Laparoscopic Liver Surgery: From Indication to Implementation. Ann Surg 2017; [Epub ahead of print]. [Crossref] [PubMed]
2. Ciria R, Cherqui D, Geller DA, et al. Comparative Short-term Benefits of Laparoscopic Liver Resection: 9000 Cases and Climbing. Ann Surg 2016;263:761-77. [Crossref] [PubMed]
3. Sotiropoulos GC, Prodromidou A, Kostakis ID, et al. Meta-analysis of laparoscopic vs open liver resection for hepatocellular carcinoma. Updates Surg 2017;69:291-311. [Crossref] [PubMed]
4. Machairas N, Sotiropoulos GC. Diffusion of laparoscopic liver resections: are we there yet? Laparosc Surg 2018;2:14. [Crossref]
5. . Obesity: preventing and managing the global epidemic. Report of a WHO consultation. World Health Organ Tech Rep Ser 2000;894:i-xii, 1-253. [PubMed]
6. McCurry J. Japan battles with obesity. Lancet 2007;369:451-2. [Crossref] [PubMed]
7. Benoist S, Panis Y, Alves A, et al. Impact of obesity on surgical outcomes after colorectal resection. Am J Surg 2000;179:275-81. [Crossref] [PubMed]
8. Dhar DK, Kubota H, Tachibana M, et al. Body mass index determines the success of lymph node dissection and predicts the outcome of gastric carcinoma patients. Oncology 2000;59:18-23. [Crossref] [PubMed]
9. Pi-Sunyer FX. Medical hazards of obesity. Ann Intern Med 1993;119:655-60. [Crossref] [PubMed]
10. Sotiropoulos GC, Machairas N, Stratigopoulou P, et al. Laparoscopic liver resection for malignancy in high-risk surgical patients according to ASA classification. J BUON 2016;21:1398-402. [PubMed]
11. Vigano L, Kluger MD, Laurent A, et al. Liver resection in obese patients: results of a case-control study. HPB (Oxford) 2011;13:103-11. [Crossref] [PubMed]
12. Nomi T, Fuks D, Ferraz JM, et al. Influence of body mass index on postoperative outcomes after laparoscopic liver resection. Surg Endosc 2015;29:3647-54. [Crossref] [PubMed]
13. Machairas N, Kostakis ID, Mantas D, et al. Laparoscopic hepatectomy in a morbidly obese patient with liver cirrhosis: A case report. Mol Clin Oncol 2017;6:233-4. [Crossref] [PubMed]
14. Ome Y, Hashida K, Yokota M, et al. The safety and efficacy of laparoscopic hepatectomy in obese patients. Asian J Surg 2019;42:180-8. [Crossref] [PubMed]
15. Toriguchi K, Hatano E, Sakurai T, et al. Laparoscopic liver resection in obese patients. World J Surg 2015;39:1210-5. [Crossref] [PubMed]
16. Uchida H, Iwashita Y, Saga K, et al. Benefit of laparoscopic liver resection in high body mass index patients. World J Gastroenterol 2016;22:3015-22. [Crossref] [PubMed]
17. Sotiropoulos GC, Prodromidou A, Machairas N. Meta-analysis of laparoscopic vs open liver resection for hepatocellular carcinoma: The European experience. J BUON 2017;22:1160-71. [PubMed]
18. Cauchy F, Fuks D, Nomi T, et al. Risk factors and consequences of conversion in laparoscopic major liver resection. Br J Surg 2015;102:785-95. [Crossref] [PubMed]
19. Halls MC, Cherqui D, Taylor MA, et al. Are the current difficulty scores for laparoscopic liver surgery telling the whole story? An international survey and recommendations for the future. HPB (Oxford) 2018;20:231-6. [Crossref] [PubMed]
20. Hasegawa Y, Wakabayashi G, Nitta H, et al. A novel model for prediction of pure laparoscopic liver resection surgical difficulty. Surg Endosc 2017;31:5356-63. [Crossref] [PubMed]
21. Edholm D, Kullberg J, Karlsson FA, et al. Changes in liver volume and body composition during 4 weeks of low calorie diet before laparoscopic gastric bypass. Surg Obes Relat Dis 2015;11:602-6. [Crossref] [PubMed]