Prediction of the operative time for hysteroscopic myomectomy for leiomyomas penetrating the intramural cavity using leiomyoma weight and clinical characteristics of patients

Abstract

Purpose: To preoperatively predict the operative time (OT) for hysteroscopic myomectomy for G1 or G2 leiomyoma based on leiomyoma weight.

Methods: The data from 544 patients who underwent one-step hysteroscopic myomectomy were analyzed retrospectively. A total of 340 patients with leiomyoma penetrating the intramural cavity were identified as suitable candidates for calculation of the OT based on leiomyoma weight; we considered leiomyoma weight to be the most objective parameter for evaluating leiomyoma tissues. Additionally, 460 patients with a single leiomyoma were analyzed to estimate the weight of the resected leiomyoma based on its diameter.

Results: Considering total leiomyoma weight (TLW) and two additional coefficients (1.5: G2 leiomyoma, 0.75: vaginal parity of the patient), we demonstrated that our formula correlated well with OT (R ² = 0.72). TLW also correlated well with the cube of the average diameter (AD) of leiomyomas (R ² = 0.89). Predicting TLW significantly improved the application of specific coefficients depending on its value (1.0: AD 0.1-2.0 cm, 0.8: AD 2.1-3.0 cm, 0.7: AD 3.1-5.7 cm).

Conclusion: The OT for hysteroscopic myomectomy of intracavital leiomyoma can be predicted prior to surgery using simple clinical information of the target leiomyoma and the patient.

Keywords: average diameter; degree of protrusion; operation time; patient parity; total leiomyoma weight.

Figure 1

Data analysis flow chart. In total, hysteroscopic myomectomy was performed on 557 patients between January 2006 and March 2016. After excluding 13 cases due to insufficient clinical data, 544 cases were analyzed. Among them, 460 cases in which a single leiomyoma was removed were analyzed to assess the relationship between the AD and the TLW. Three hundred forty cases were analyzed to provide a formula to predict the degree of surgical difficulty. For practical utility, the following 204 obviously easy or difficult cases were excluded: (a) 104 G0 cases in which all operations were completed within 50 minutes; (b) 83 cases with a TLW <3 g in which 98% of all operations were completed within 30 minutes; and (c) 17 cases with a TLW >40 g in which 94% of all operations could not be performed within 50 minutes

Figure 2

Estimated risk of difficult operation. To assess the validity of the cTLW for predicting OT, seven subgroups were created according to the values of the cTLW or TLW: <5, 5.1‐10, 10.1‐15, 15.1‐20, 20.1‐25, 25.1‐30, and over 30.1. In each subgroup, the probability of difficult hysteroscopic myomectomy was calculated and it was defined as the probability of DHM. The solid line with black squares and dotted line with black circles showed the values of TLW and cTLW. The number of cases is displayed in brackets. DHM, difficult hysteroscopic myomectomy; OT, operation time; TLW, total leiomyoma weight

Figure 3

Formula of estimated OT. Formula of OT (min) is consisted of AD and 3 coefficients. AD is defined as the average diameter of the target leiomyoma. After defining the largest sagittal view of the lesion, the longest part of the lesion (x) and the orthogonalizing part (y) was measured, and then, (x + y)/2 = AD (cm) was calculated.