Minimally invasive approaches to surgery have been introduced across surgical disciplines with the objectives of decreasing postoperative morbidity while maintaining effectiveness. New surgical approaches must be evaluated in terms of safety, feasibility, clinical effectiveness, and the learning curve surgeons encounter when adopting a new technique. The cost implications of the introduction of new surgical techniques must be considered as part of this evaluation, particularly given the economic implications for many healthcare systems [1, 2].

The adoption of minimally invasive approaches to hepatic resection has slowly gained momentum over the last several years after its initial description in 1992 [3]. The growth has been supported by retrospective case series and case-controlled series demonstrating trends in decreased blood loss, length of stay, and overall morbidity while maintaining similar clinical and oncologic outcomes [4]. Critics of LLR have suggested potential higher costs due to the increased use of new technology and disposable instruments; however, to date the cost implications of LLR have not been extensively reported or studied.

The initial global experience with laparoscopic liver surgery was evaluated at the 1st International Consensus Conference on Laparoscopic Liver Resection (ICCLR) in Louisville in 2008 [5]. Given the rapid developments and expanding experience in LLR, the 2nd ICCLR was convened in Morioka, Iwate, Japan, in October 2014 [6]. Seventeen questions on the risk, benefits, and techniques of LLR were evaluated by expert panels and presented to a nine-member jury using the Zurich-Danish consensus conference model. As part of this consensus process, the authors were asked to review the available literature on the cost implications of LLR compared to open liver resection (OLR).

Methods

Study selection

A systematic review of the English language literature was performed using MEDLINE, Embase, PubMed, and Cochrane databases to identify all studies from 1991 using the medical subject heading (MeSH) terms “laparoscopy,” “minimally invasive surgery,” “laparoscopic,” “liver resection,” “hepatic resection,” “lobectomy,” “sectionectomy,” “segmentectomy,” “wedge resection,” “economic,” “cost,” and “comparison.” All identified publications were cross-referenced, and citations were analyzed to broaden the search. Complete manuscripts as well as available supplementary materials were reviewed. A final search prior to the ILCCR meeting in Morioka, Japan, was performed on September 12, 2014, and the search was updated on May 30, 2015, prior to submission of the final manuscript.

Inclusion/exclusion criteria

Studies were included in the review if the in-hospital or postdischarge costs of laparoscopic and open liver resection were assessed and reported. Studies that focused on non-resective liver operations, living donor transplant hepatectomy, and those where cost data could not be identified were excluded. This review focused only on laparoscopic procedures, and therefore, robotic or robotic-assisted cases were excluded.

Data extraction and analysis

Abstracts and manuscripts were screened by members of the expert panel (SPC, HA, HSH) for relevance to the stated hypothesis. Appropriate publications that met the inclusion/exclusion criteria were selected; complete manuscripts and supplementary materials were reviewed by all three panel members. The following data were abstracted from each relevant publication: first author, last author, publication year, journal name, country of study, currency reported, years of study, study design, number of cases (laparoscopic and open), number of major/minor hepatectomy, total hospital length of stay (LOS), intensive care unit (ICU) admission/LOS, total costs, operating room (OR) costs, instrument/disposable costs, ward, and ICU costs.

The quality of publications was assessed using the GRADE system [7] to assess the study design and the MINORS criteria to evaluate the methodology of observations non-randomized trials [8] as described by Wakabayashi et al. [6].

Results

A total of 26 publications were identified by the initial literature search in August 2014, and 18 were selected for full panel review. Following assessment of the three panel members, seven studies met the inclusion/exclusion criteria and focused on comparative costs between OLR and LLR. One paper [9] was excluded because it only compared costs of stapler utilization. The results of this review were then presented to the jury at the 2nd ICCLR meeting in Morioka, Japan, in October 2014. After a second literature review was completed in May 2015, an additional eight abstracts were screened and four relevant papers was added to the analysis resulting in a total of 11 manuscripts addressing the costs of LLR compared to OLR (Table 1).

Table 1 Characteristics of studies comparing costs of open versus laparoscopic liver resection
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The 11 publications identified were all retrospective in nature, and there were no randomized or prospective studies. Methodologies included retrospective reviews and case-matched series. Two publications [11, 12] used a deviation-based cost modeling (DBCM), which measures the occurrence and severity of complications that deviate from the normal postoperative course and the financial implications of these deviations. Nine series described a predominantly pure laparoscopic approach to hepatic resection, while one center [13] employed a hand-assisted laparoscopic approach for all cases. Four papers analyzed the outcomes of laparoscopic (LLLS) versus open left lateral sectionectomy (OLLS) [11, 14–16]. Abu Hilal et al. [17] provided separate comparisons for LLLS versus OLLS and open (ORH) versus laparoscopic right hepatectomy (LRH). Two papers included a mix of minor and major hepatectomy [12, 18], while Medbery et al. [13] analyzed outcomes for right hepatectomy only. Among the 11 publications, cost analyses for 306 minor and 137 major laparoscopic hepatic resections are considered. The majority of analyses compared costs from a variety of aspects of surgical care including operating room, inpatient care, and total hospital costs, while Dokmak et al. [16] only reported total hospital costs. All papers reported costs in local currency, except for Kawaguchi et al. [19] that reported outcomes from a Japanese center but reported costs in Yen and US dollars (USD).

Cases that were converted from laparoscopic to open may have significant impact on the results of cost comparisons; the reviewers specifically noted the manner in which converted cases were handled in each analysis. Three manuscripts either explicitly excluded converted cases or were not included in the analysis [15, 19, 20], while one manuscript analyzed converted cases in the open group [12]. In the remaining manuscripts, converted cases were considered on an intention-to-treat basis and were analyzed in the laparoscopic group. Cases in each analysis were typically collected over several years (range 2–11 years), but only one study [18] adjusted for inflation over the study period in their analysis.

There was significant heterogeneity between studies on the source of cost data and the comprehensiveness of items included in the cost analysis. As a result, comparisons or aggregation of data across studies was not feasible. The results for 9/11 studies which reported operating room costs are presented in Table 2. Seven studies reported no difference in operating room costs between laparoscopic and open hepatic resection, while one study of LLS only reported statistically significant lower costs of LLLS over OLLS [14]. Two studies examining right hepatectomy reported significantly higher operating room costs for LRH compared with ORH [13, 17]. Nine studies reported reductions in hospital length of stay (LOS) with laparoscopic hepatic resection compared to patients undergoing open procedures, shown in Table 3. This reduction in LOS resulted in five studies reporting statistically significant reductions in hospital ward costs with differences ranging from −16 % to −49 %. Three studies did not show a statistically significant difference in ward costs, while none of the published analyses showed higher inpatient costs with laparoscopic surgery. The reported results for total hospital costs are reported in Table 4. The relative difference in total costs of LLR compared to OLR ranged from +2 % to −35 % with 7/11 studies demonstrating statistically significant reductions for LLR; two studies reported borderline statistically significant costs savings, and one analyses demonstrated significant cost savings for LLLS and no difference in costs for LRH compared to matched open procedures.

Table 2 Operating room costs of laparoscopic versus open liver resection
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Table 3 Inpatient ward costs of laparoscopic versus open hepatectomy
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Table 4 Total hospital costs for laparoscopic versus open hepatectomy
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Discussion

New surgical techniques are evaluated by a variety of outcomes and metrics to assess their equivalence or superiority over existing procedures, including efficacy, safety, morbidity, and mortality. In the evolution of minimally invasive luminal gastrointestinal and abdominal solid organ surgery, comparisons have focused on enhanced recovery, improved cosmesis, and decreased adhesions, pain, and length of postoperative hospitalization associated with laparoscopic procedures. Costs are an important and often debated metric by which laparoscopic procedures may be assessed and are highly relevant in both publicly and privately funded healthcare systems. Furthermore, the assessment of costs can be considered a form of “composite metric” as operating room equipment and time, length of stay, pain, and complications all contribute to the costs associated with a patients operation and postoperative care. The questions regarding the expense of laparoscopic hepatic resection are particularly relevant given the costs of specialize operative equipment used in these procedures and the questionable impact of a minimally invasive approach to major abdominal operations on postoperative outcomes.

We identified 11 studies examining the cost of LLR compared to OLR published by a number of specialized hepatobiliary surgical centers with extensive experience in minimally invasive liver resection. These series represent a variety of countries and healthcare environments in Europe, North America, and Asia and are therefore likely representative of the global perspective on this topic for experienced centers. The components of cost and the comprehensiveness of financial assessments likely differ between series as all authors utilized hospital-based accounting data for their analyses. A variety of study methodologies was used with the predominance of studies being retrospective case series or case-matched series. The identified series examining costs are comparatively small with 10–57 laparoscopic procedures reported per study compared to open procedures in a 1:1–1:2 ratio. Of the procedures described in the cost analyses, 306/443 (69 %) were minor (<3 segment) hepatic resection; while this is reflective of the overall published experience of LLR, it is likely that the global practice of LLR is more heavily weighted toward minor resections.

From the examined published series, several consistent themes emerge. Ten out of the 11 publications reported a decreased LOS associated with LLR and that length of hospital admission is a major contributor to overall costs in each series. Statistically significant lower inpatients ward costs and total hospital costs were reported in the vast majority of series. Operating room costs were similar in most series except for two publications that demonstrated higher operating room costs for major hepatectomy. The magnitude of the hepatic resection (major vs minor) may have an impact of the results of costs comparisons. Studies comparing minor hepatic resections only consistently demonstrated lower inpatient and total hospital costs with similar operating room costs for laparoscopic operations. The two series that examined costs associated with LRH reported higher operating room costs, similar or lower inpatient costs, and similar total hospital costs compared with ORH. The publications that had a mix of minor and major resections demonstrated results that were intermediate between the observations of series including minor or major resections depending on the mix of cases in each analysis.

There are certainly several limitations in the assessment of cost implications of LHR at this point in time. We were only able to identify 11 studies that performed comparative cost analyses of LHR compared to OHR. Only seven of these manuscripts were available at the time of the International Consensus conference, and therefore, the jury was only able to evaluate a limited number of studies. However, the observations of subsequent four studies did concur with the overall results of the studies reviewed at the ILLCR and thus added to the quantity of data, particularly with respect to major resection, upon which we can draw some conclusions. It is clear from the dates and frequency of publications that the evidence in this area is still evolving. All studies identified were comparatively small (largest N = 57 LHR) retrospective in nature, and there is no prospective study data on LHR at this time. All studies were single institution based, and multi-site or health system analyses were not available. The studies examined used a variety of methods to improve the quality of their comparisons including case matching and restricting comparisons to one procedure (either LLLS or LRH). Combining data from multiple small studies in a meta-analytic approach can improve the quality of the analyses and conclusions. However, combining cost information from studies performed in multiple countries and time periods would require proper time-specific currency and inflation data for each country- and case-level cost data. Finally, there is always the possibility of reporting bias in that studies that are either null or show increased costs of LR may not be either submitted or accepted for publication. However, it is worth noting that of the publications reviewed, both increased and decreased costs of LR were observed.

At the second ICCLR the expert panel presented the available data to the jury. Based on these data, the jury felt that the cost comparisons for minor and major hepatectomy should be considered separately as the data indicated differences between studies based on the inclusion of major hepatic resections. The jury concluded that, based on consistent reproducible data from numerous retrospective series, there was a cost benefit to laparoscopic minor hepatectomy. Cost savings for minor LHR were achieved predominantly through decreased length of stay and hospital costs, while operating room costs appear to be similar. There was insufficient evidence to make robust conclusions on the cost implications of major LHR at the time. Since the conference, one additional publication [13] has added to the data on major LHR. Taken together, the series that have analyzed costs of major LHR seem to indicate that, at present, total costs are comparable to major OHR with higher operating room costs being offset by lower hospital costs and shorter length of stay. The issue of costs of major LHR is certainly not conclusive, and further study in this area is required. It is worth noting that, due to practical considerations, all of the studies evaluated measured direct hospital costs and did not measure indirect costs associated with hepatic resection including lost productivity, return to work, post-discharge caregiver expenses. Given the enhanced recovery and lower postoperative cost of LHR, it is likely that direct costs may underestimate the true benefit of LHR and that real savings in direct and indirect costs may be realized once out of hospital costs are considered.