Large Uterus Classification System stratifies surgical risk and technique in TLH

The removal of a large uterus invariably represents a surgical challenge, regardless of the surgical route. Regardless of its potential advantages, total laparoscopic hysterectomy (TLH) for large uteri remains a challenging procedure. The estimated weight alone does not appear enough to guide the surgical technique and predict surgical outcomes and complications.

Stefano Uccella and team observed that, apart from the actual weight of the uterus, a possible additional contributing factor impacting the ability to perform a TLH for a large uterus is the presence of displaced uterine or adnexal vascular pedicles.

From this observation, they developed the Large Uterus Classification System (LUCS), which is based on the intra-operative assessment of the uterine and adnexal vascular pedicles.

The researchers hypothesized, "if the surgical difficulty of a TLH is truly associated with the displacement of uterine or adnexal vessels, the type of large uterus defined by this system may be associated with different surgical outcomes and complications." A prospective observational study was conducted to evaluate whether this hypothesis is correct: the type of large uteri defined by the proposed LUCS is associated with the rate of conversion to open surgery, the operative time, the estimated blood loss, and total complications published in British Journal of Obstetrics and Gynecology.

All consecutive patients with a large uterus (defined as having the uterine fundus at or over the transverse umbilical line) undergoing a TLH between June 2004 and September 2019 at the University of Insubria and the Hospital of Biella, Italy, were included.

All TLHs were performed by the same two surgeons: SU at the Hospital of Biella and the University of Insubria and FG at the University of Insubria. A detailed description of the initial laparoscopic inspection and appearance of the uterus was performed and documented in the operative notes of all patients. According to the proposed LUCS, the classification of the uterus was accomplished by the primary surgeon at the time of the initial laparoscopic inspection and was recorded in the operative reports.

The primary outcome was the total complication rate, defined as the sum of intraoperative and postoperative complication rates. Secondary outcomes were conversion to open surgery, operating time, estimated blood loss, length of hospital stay, and the rate of complications with a Clavien-Dindo classification score ≥ 2.

The Large Uterus Classification System (LUCS)

Based on the hypothesised impact of displaced uterine and adnexal vascular pedicles on the ability to perform a TLH for large uteri, researchers developed the LUCS, which classifies each large uterus into one of three different types. The surgical technique adopted for each type of uterus was reported.

Type 1: Uterus with adnexal vascular pedicles (i.e., the infundibulopelvic ligament and utero-ovarian ligaments) and uterine vessels that are approximately at the same level as a normal-size uterus. This type of large uterus can be observed, for example, in the case of large fundal myoma. In this type of large uterus, surgeons utilised steps for the TLH that resemble a standard procedure employed for normal-sized uteri.

Type 2: Uterus with cranially displaced adnexal vascular pedicles, at least on one side, but with uterine vessels approximately at the same level of a normal-size uterus.

In this type of large uteri, the technical difficulty involves managing the adnexal blood supply, which can be challenging to access utilising standard trocar positions. To overcome the technical challenges that this type of uterus entails, a 5-mm 0-degree scope can be inserted in one of the suprapubic ancillary trocars, and the umbilical trocar serves as an operative port. Alternatively, the optical and ancillary trocars were positioned more cephalad to optimise access to the displaced adnexal structures and their associated blood supply.

Type 3: Uterus with displaced uterine vessels and with or without displaced adnexal vascular pedicles. This type of large uterus is characterized by markedly challenging access to the uterine artery and vein; the ureter can be displaced laterally or cranially. Usually, this condition is related to the presence of large cervical or lower uterine segment fibroids.

For Type 3 uteri, the following possible surgical tips are suggested:

1) opening of the retroperitoneum with development of the pararectal and paravesical spaces, to identify the ureters and to follow them to their entrance in the parametrial tunnel (this step allows the exposure of the ureter and preventing inadvertent ureteral damage);

2) ligation of the uterine artery at its origin from the internal iliac artery (with the ureter under vision) to obtain devascularisation of the uterus at the beginning of the procedure and minimise possible bleeding;

3) when present and feasible, isolation and cranial mobilisation of the cervical fibroid to obtain better upward mobilisation of the uterus and avoid excessive bleeding when in close proximity to the deep uterine vein,

4) completion of the procedure after obtaining adequate mobilisation of the uterus.

Results:

• A total of 392 patients having a uterus with uterine fundus at or over the transverse umbilical line underwent TLH during the study period. The procedure was completed laparoscopically in 363 cases (92.6%). 251 (64%) patients were classified as type 1 uterus, 82 (20.9%) women as type 2, and 59 (15.1%) cases as type 3 uterus.

• Uterine weight was lower in Type 1 than Type 2 and 3 (p<0.001)

Significant differences were observed amongst groups in terms of:

• Conversions to open surgery (6% in Type 1, 6.1% in Type 2 and 15.3% in Type 3; p=0.03),

• Operative time (112, 137 and 147 min for Type 1, 2 and 3 uteri, respectively; p<0.001)
• Blood loss (210, 342, 338 mL for Type 1, 2 and 3 uteri, respectively; p<0.001)
  

• Postoperative complications (8.8%, 14.6% and 18.6% for Type 1, 2 and 3 uteri, respectively; p=0.04)

• Total complications (9.6%, 17%, 22% for Type 1, 2 and 3 uteri, respectively; p=0.018)

• The hospital stay was similar across the three different uterine types (1.9, 2, and 2.2 days in type 1, 2, and 3 uteri, respectively; p=0.32).

• A longer operative time and a higher blood loss were noted in Type 2 vs. Type 1 uteri.

• A higher rate of total complications was registered in Type 2 vs. Type 1 uteri, although the total complication rate did not reach the conventional level of statistical significance (17% vs. 9.6%, respectively; p value=0.06).

• On the other hand, the conversions rate to open surgery was similar between these two groups. The operative time, blood loss, rate of postoperative complications, total complications, and the conversion rate were significantly higher in Type 3 vs. Type 1 uteri.

• The posthoc pair-wise comparison between Type 2 and Type 3 uteri showed two categories were similar in terms of operative outcomes, but there was a higher rate of conversion to open surgery in the group of Type 3 than Type 2 uteri, although without the conventional level of statistical significance.

• At the multivariable analysis , the classification as Type 2-3 uteri was the only independent predictor of a higher rate of total complications than Type 1 uteri. Neither age nor previous abdominal surgery was predictors of total complications.

Researchers observed that in the case of a large uterus having its fundus at or over the transverse umbilical line, the uterine type defined according to the proposed LUCS is associated with surgical outcomes regardless of the uterine weight.

When conducted systematically, the intra-operative use of the LUCS system may be a useful tool to classify large uteri at the beginning of the TLH and predict surgical outcomes and complications. The adoption of the LUCS may allow the surgical team to tailor the operative technique to the difficulty of the case to optimise surgical outcomes.

The study's findings from this prospective observational study suggest that the displacement of the vascular pedicles correlates with the surgical outcomes and complications, representing a potential marker of technical difficulties. The proposed LUCS classification may represent a simple intraoperative method to deliver valuable information to the surgeon regarding surgical outcomes and the risk of complications in TLHs for enlarged uteri.

However, external validation of the LUCS is needed before achieving a definitive conclusion on its utility. Moreover, further research should focus on developing an accurate preoperative method to assess the uterine type before surgery to plan the surgical strategy preoperatively. This would improve surgical outcomes, avoiding the possible morbidity associated with a change of surgical approach intra-operatively.

doi: 10.1111/1471-0528.16753