Minimally invasive surgical approaches were designed to enhance quality of care and improve patient outcome by minimizing postoperative morbidity, shortening hospital stay, and reducing costs. While laparoscopic surgery has made significant strides across the full spectrum of abdominal procedures, liver surgeons have for the most part been slow and deliberate in their adoption of laparoscopic hepatectomy. Concerns regarding the mobilization, transection, and vascular control of the liver as well as the risks of major hemorrhage, gas embolism, bile leak, and dissemination of malignant tumors have all contributed to the initial slow adoption. More recently, however, increased experience in laparoscopic liver surgery coupled with the development of improved surgical instruments, techniques, and technologies have reinvigorated the field of laparoscopic liver surgery.
At the University of Pittsburgh Medical Center (UPMC) approximately 25% of liver resections are completed laparoscopically (unpublished). In contrast, Koffron et al. have recently reported a dramatic shift in their laparoscopic approach from 10% of cases in 2002 to 80% in 2007.24
Thus, while most liver surgeons have not yet fully embraced minimally invasive liver resection, considerable progress has been made towards that goal in select centers.
Driving the adoption of laparoscopic hepatectomy is increasing evidence that this approach is not only safe and feasible but also confers patients with meaningful clinical benefits which may not be equaled by open hepatectomy. In fact, Koffron et al. showed that patients undergoing laparoscopic resection had decreased operative times (99 versus 182 min), blood loss (102 versus 325 ml), transfusion requirement (2 of 300 versus 8 of 100), length of stay (1.9 versus 5.4 days), overall operative complications (9.3 versus 22%), and local malignancy recurrence rate (2% versus 3%).24
In other studies looking specifically at LLS, the vast majority of these aforementioned clinical benefits were replicated.25,26
For example, Lesurtel et al. undertook a case–control study comparing laparoscopic LLS with matched open LLS.20
They found that, despite longer operative times, the laparoscopic cohort benefited from decreased blood loss and no noticeable increase in postoperative morbidity, thus demonstrating that laparoscopic LLS was at least as safe as open resection. This study also highlighted that the postoperative course of cirrhotic patients in particular was improved with the laparoscopic approach, suggesting a unique benefit of this approach in patients with chronic liver disease. Other studies have corroborated this intriguing finding.27
To more clearly delineate the clinical and economic impact of laparoscopic versus open hepatectomy, we chose to leverage the DBCM approach. Deviation-based cost modeling provides a valuable tool for evaluating the combined clinical and fiscal impact of deviations from the expected hospital course for a given procedure, thereby permitting a rigorous comparison of two techniques. DBCM was specifically designed to overcome the limitation inherent to all descriptive complication models such as the Clavien classification model. While accurately describing the severity of the complication, descriptive models say little about the resulting LOS and economic impact of any given complication. Deviations, intrinsically, not only incorporate the clinical sequelae of complications because they represent departures from an expected hospital course but also take into account an important driver of costs, i.e., LOS. In essence, by combining complication data and their clinical sequelae with LOS data, deviations are able to more accurately characterize the clinical and economic impact of complications of variable severity.
The major strengths of the DBCM approach are its versatility, generalizability, usefulness as a quality-assurance tool, and ability to link changes in clinical outcomes (deviation mix) to downstream economic impact. Its versatility and generalizability are based on the fact that a deviation mix can be generated for any procedure in any institution since it is based on institution-specific LOS and a standardized complication classification model. Similarly, DBCM’s ability to measure variance in clinical outcomes using the concept of deviation mix is unique and provides a helpful yardstick to track outcome data as well as measure and track quality of care. Lastly, DBCM’s ability to accurately characterize the variable impact of complications on hospital efficiency is linked to the concept of WAMC, which is able to link quality and consistency of care (deviation mix) to hospital costs by combining the relative proportion of each deviation with its median hospital cost.
Using a DBCM approach, our results substantiate the aforementioned clinical benefits gained with the laparoscopic approach to LLS. Not only was the length of stay shorter by 2 days in the laparoscopic cohort, but patients undergoing the minimally invasive approach also benefited from a greater likelihood of experiencing less postoperative morbidity as measured using the Clavien postoperative complication model compared with the open cohort. Both of these clinical benefits were maintained in patients undergoing laparoscopic LLS for malignant disease compared with similar patients undergoing open resection. However, while the net reduction in LOS was equivalent across the entire LG and the malignant LG cohort, patients undergoing laparoscopic LLS for malignant disease did have a slight shift towards higher-grade minor complications (with no noticeable increase in more severe postoperative complications) as well as a modest shift in deviation mix from on-course to minor and moderate deviations. These findings seem to suggest that, overall, patients with malignant disease undergoing laparoscopic LLS had a relatively more complicated postoperative course compared with the entire laparoscopic cohort. Furthermore, patients with malignant disease undergoing laparoscopic LLS are also more costly per deviation and have a 12% higher WAMC when compared with the entire laparoscopic cohort, probably as a result of the above-mentioned shift in complication and deviation mix, despite having an equivalent median LOS. Interestingly, no similar shift in complication grade, deviation mix or cost (WAMC) was evident in patients undergoing open LLS for malignant disease compared with the entire open cohort.
While the vast majority of patients undergoing laparoscopic LLS for malignant disease continued to experience an uncomplicated postoperative course and were able to maintain a favorable cost benefit over open surgery, this study does highlight two important points. First is the need to differentiate whether a laparoscopic operation is done for benign or malignant disease when comparing the relative clinical and economic superiority of this approach as compared with open hepatectomy. Second is the caveat that, while laparoscopic hepatectomy is applicable in both benign and malignant disease, in general, patients with malignancies appear to fare somewhat less well than patients undergoing surgery for benign disease. This may be related to the added complexity of the case when dealing with malignant disease or may simply be related to patient factors that make this patient population more susceptible to postoperative complications.
While our paper provides evidence that any laparoscopic approach (pure laparoscopic or hand assisted) is potentially clinically superior to the traditional open approach, there does appear to be a net 1 day length-of-stay benefit in laparoscopic cases that did not utilize a hand-port incision. The PL approach does not, however, appear to confer any substantial clinical benefit beyond shortening the hospital stay, as our study did not observe any meaningful changes in postoperative morbidity between the groups. These findings seem to also underscore the importance of differentiating laparoscopic approaches when comparing the clinical and economic utility of laparoscopic surgery relative to open surgery. Taken as a whole, it appears that any laparoscopic approach may advance patient care and improve patient outcomes compared with traditional open hepatectomy.
In addition to its apparent clinical benefit, the laparoscopic approach seems to also offer an economic benefit.24
In a study by Polignano et al. which compared laparoscopic versus open liver segmentectomy in a prospective, case-matched fashion, the authors demonstrated a significant reduction in overall hospital costs with the laparoscopic approach.28
By examining the average unit costs for theater time, disposable instruments, high-dependency unit (HDU), ward stay, and overall costs, the authors were able to demonstrate that, although theater time costs did not differ, the laparoscopic approach, while costing more in disposable operating room instruments, rapidly recovered those upfront costs by reducing HDU and ward costs. Ultimately, the laparoscopic approach was found to be GB £2,571 (~ US$3,800) more cost-efficient than the corresponding open approach.
Our results demonstrate a similar trend, with both analyses revealing a shortening of LOS, a relative parity in operative time, and comparative cost savings associated with the laparoscopic approach. However, once again the underlying disease for which the operation was performed has an impact on the overall cost savings gained, with patients undergoing laparoscopic LLS for malignant disease having lower relative cost savings as compared with patients undergoing the same operation for benign disease. That is, compared with the traditional open approach, laparoscopic LLS was found to have a weighted-average median (loaded) hospital cost advantage of US$2,939 if one considers the entire cohort of patients, or cost savings of US$1,412 when only comparing patients undergoing LLS for malignant disease. This difference is presumably due to both a shift in deviation mix towards higher grades of deviations as well as a shift towards higher-grade minor complications, thereby leading to a relative increase in the total loaded costs. Nonetheless, the laparoscopic approach remains more cost-effective than the open approach, irrespective of the underlying pathology prompting the operation. These data do however highlight that, when comparing the relative clinical and economic utility of competing surgical approaches, it is important to differentiate whether an operation is done for benign or malignant disease.
Underlying these cost difference are several related and interdependent factors. First, it is important to remember that, at baseline, the LG has a median LOS of 2 days less than the OG, which by itself has economic implications. Other studies investigating the cost-effectiveness of laparoscopic hepatectomy have demonstrated that a significant portion of the cost savings associated with the minimally invasive approach are primarily associated with a reduction in length of stay.24
Second, the cost savings observed in this report, while heavily driven by the reduction in LOS, may also be indirectly driven by a reduction in resource utilization. While not directly investigated, it is possible that, as a consequence of the reduction in complication severity and deviations from the expected postoperative course, patients undergoing laparoscopic resection may utilize less ancillary services such as laboratory, radiology, and pharmacy, thereby leading to an overall cost reduction. This latter association warrants further investigation.
Lastly, we found that the overall cost-effectiveness of laparoscopic surgery is significant impacted by the type of laparoscopic approach chosen; that is, not all laparoscopic hepatectomies are created equal. When comparing the WAMC of the PL versus the HA approaches, the results highlight that the PL hepatectomy is US$2,819 more cost-effective than the HA approach. While some of this cost advantage is due to the overall net 1 day reduction in LOS, some of the costs may be related to the reduced operative time, decreased operating room material costs, and perhaps an improvement in on-course postoperative recoveries. More dramatic is the cost savings per case when comparing open LLS with pure laparoscopic LLS. In fact, when compared against the open approach, the PL approach is US$5,490 more cost efficient.
Overall, our study not only supports the clinical benefit of the laparoscopic approach to LLS but also suggests a fiscally important cost advantage for the minimally invasive approach. While not all laparoscopic approaches are equal, any minimally invasive approach may be an advance beyond the traditional open approach on clinical and economic fronts. Our data lends support to the assertion that laparoscopic hepatectomy fulfills the clinical and economic promises of minimally invasive surgery and has the potential to emerge as the standard approach for LLS. Lastly, our report corroborates the utility of the DBCM approach and suggests that it should be considered by any hospital interested in linking quality and consistency of care outcomes to economic ramifications