The characteristics of patients who underwent hysterectomy by each method are summarized in . The average age across all three cohorts was similar. Those who underwent TRH tended to have the highest BMI (40.5, P
< 0.01), while those who underwent TLH tended to have lowest BMI (29.8, P
< 0.01). On average, patients who underwent TLH were less surgically complex than patients who underwent hysterectomy by other methods. These patients tended to have the lowest incidence of prior laparotomy, prior laparoscopy, and presence of adhesions. Moreover, patients selected for TLH had the lowest average uterine weight (134.4
g). By contrast, patients selected for TAH had the greatest average uterine weight (243.5
g). Patients who underwent TAH were also significantly more likely to also undergo staging with lymph node dissection (74%, P
< 0.01), compared to TLH (38.5%) and TRH (37.9%). Multivariate regression demonstrated a small correlation between lymph node dissection and hysterectomy type (R
= 0.3, P
< 0.01), as well as uterine weight and hysterectomy type (R
= 0.18, P
Cohort characteristics. Number and % or mean and standard deviation (range).
Perioperative outcomes and complications are summarized by hysterectomy type in . On average, TRH required the longest use of the operating room (including the skin-to-skin surgical time, setup, and turnover times), totaling 252.6 minutes (P
< 0.01). Estimated blood loss was significantly lower for patients who underwent TLH and TRH compared to patients who underwent TAH (P
< 0.01). Compared to patients who underwent TAH, patients who underwent TLH and TRH also stayed in the hospital for a significantly lower amount of time (P
< 0.01), consistent with length of stays reported elsewhere in the literature [12
Perioperative outcomes and complications by hysterectomy type. Mean (SD) and range or number and (%).
The rate of conversion to laparotomy was 5.1% for TLH and 0% for TRH. Intraoperative complication rate was very low with single incident of organ injury for TAH and TLH (bladder injury in both cases) and a single incident of EBL greater than 1000
mL reported for TAH and TLH, and no complications reported for TRH. Postoperative complication rates were similar across all three cohorts.
Cost approximations are summarized in , based both on hospital accounting ledgers for each patient in our database (total mean operative charge and total mean encounter charge), as well as our cost model which additionally accounts for variation in OR time and indirect societal costs (expected societal cost). As described in Section 2
, these cost approximations are upper-bound estimates based on standard hospital charges. Notably, analysis of variance demonstrated that operative charges were most strongly driven by operating room time (P
< 0.01) with an R
-value of 0.963. No other variable was significantly associated with operative charges, and the charges associated with time use were 190-fold greater than charges associated with equipment. It is therefore not surprising that the total mean operative charge for TRH is the highest (P
< 0.01), given that TRH also required the longest time use of the operating room.
Mean encounter charge is highest for TAH (P < 0.01) as a result of longer lengths of stay in the hospital. The expense of TAH increases relative to the minimally invasive methods when return to work times are taken into account, and foregone wages are added to the indirect societal costs of the procedure. Ultimately, the expected total societal costs are highest for TAH and lowest for TLH.
Each probability and outcome variable in our decision tree were assigned normally distributed probability functions and then randomly sampled in a probabilistic Monte Carlo simulation in order to test the robustness of our expected societal cost estimate. demonstrates the distribution of societal costs estimates for each method of hysterectomy. In all cases, the simulation resulted in estimates that were closely clustered around our expected values.
Figure 2 Monte Carlo simulation of total expected societal costs. Expected total societal costs as determined by our model for each hysterectomy method are reported in . Below are three corresponding Monte Carlo simulations demonstrating the expected probability (more ...)
We then individually conducted a one-way sensitivity analysis on operating room time for each method of hysterectomy. In each case, as operative room time was allowed to increase, the expected total societal cost increased as well. demonstrates that, even for longer cases in our cohort, the expected societal cost of TLH is less than the expected costs of TRH or TAH. demonstrates that, over the majority of our experience in operative time, TRH is less expensive than the average expected societal cost of TAH, but still more expensive than TLH. Moreover, TRH becomes more expensive than TAH when the operating room is utilized for more than approximately 300 minutes (including the time of anesthesia induction and intubation, equipment setup, etc.) demonstrates that the fastest TAH cases in our experience approach the average expected societal cost of TRH and are more expensive than TLH by a wide margin. shows a Monte Carlo simulation of the expected incremental cost difference to society between TRH and TAH. In the majority of cases, the estimated societal cost of TRH is less than the estimated societal cost of TAH.
In all cases, TLH was consistently the least costly method to society. In our experience, it is feasible for TRH to be less expensive to society than TAH, but unlikely for TRH to be less costly than TLH.