Comparative analysis of laparoendoscopic single-site surgery and versus conventional laparoscopic surgery in adnexectomy: A systematic review and meta-analysis of surgical outcome

Masses of the ovary and adnexa are frequently encountered pathologies. The best course of treatment for these masses can vary and is not always clear to the clinician⁽¹⁾. Asymptomatic masses with a low probability of being malignant do not usually require surgical treatment. Masses that have the potential to be malignant, or are causing pain, can often be excised by laparoscopic techniques^{(2, 3)}.

It is estimated that there are 350.000 adnexal surgeries carried out each year in the USA and that 65% of these are laparoscopic or robotic in nature^{(4, 5)}. While laparoscopic adnexal surgery in most cases is straightforward, in some patients with dense adhesions, obesity, prior pelvic surgery or endometriosis, surgery can be challenging⁽⁶⁾.

In recent decades, improvements in medical technology and awareness of patients have pushed for the enhancement of minimally invasive surgical techniques. Laparoscopic surgery is preferred over open surgery because it causes less operative trauma, shorter operative time, less morbidity, faster recovery, and better cosmetic results^(7-9).

Laparoendoscopic single-site surgery (LESS) is a relatively new technique within minimally invasive surgeries. LESS is performed via a single umbilical incision using specialized instrumentation. It has the potential benefits of minimizing abdominal scarring, decreasing the risk of trocar/port complications, and the potential for decreasing analgesic requirements⁽¹⁰⁾. Some studies have recently described LESS to be safe and effective for many gynecologic surgeries including adnexectomy, cystectomy, endometrioma excision, and hysterectomy^{(11, 12)}.

In addition, as opposed to cystectomy which sometimes requires extensive dissection between the ovarian lesion and the ovary proper, removal of the entire adnexa is normally a more straightforward procedure that may lend itself more to minimally invasive techniques such as LESS.

As a result, our study aims to analyze the surgical outcomes and assess postoperative pain outcomes related to LESS and conventional laparoscopic surgery (CLS). We will limit this study to the treatment of benign ovarian lesions with oophorectomy or removal of the entire adnexal (ovary and fallopian tube).

We conducted our study based on preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines and recommendations⁽¹³⁾.

Search Strategy and Information Sources

We developed a search strategy by combining the following keywords: (“laparoscopy” OR “laparoscopic surgery” OR “minimally invasive” AND “laparoendoscopic single-site surgery” OR “LESS” AND “conventional laparoscopic surgery” OR “CLS” AND “oophorectomy” OR “salpingo-oophorectomy” OR “salpingectomy” OR “adnexectomy”, AND “benign ovarian lesions”). We searched six databases: Medline, PubMed, Cochrane Library, Web of Science, clinicaltrials.org, and SCOPUS.

Study Selection

The screening steps were performed by two independent authors. First, these authors screened the title and abstract of each paper. Following this, a full text screening was performed on the selected papers. A third author solved any potential conflict between the two authors. The articles ultimately included in our synthesis were selected according to these eligibility criteria:

• Population: Women diagnosed with benign ovarian cysts undergoing salpingo-oophorectomy with or without cystectomy. Patients who underwent cystectomy alone were excluded.

• Intervention: LESS.

• Comparator: CLS.

• Outcomes: Measures of operative outcomes (e.g., operative time, blood loss), postoperative pain, complications, and recovery metrics (e.g., hospital stay).

• Study Design: We included randomized clinical trials (RCTs), as well as observational studies.

Quality Assessment

To assess the quality of the included studies, we used the Cochrane risk of bias (ROB) assessment tool for RCTs. In addition, we used the national heart, lung, and blood quality assessment tools to assess the quality of the observational studies. Each study’s ROB was categorized as low, high, or unclear⁽¹⁴⁾.

Data Extraction

Data extraction was performed for three categories:

1. Demographic Information: This included baseline characteristics of the patients, such as age, body mass index (BMI), mass size, and previous abdominal surgery.

2. Outcomes: Data on operative time, blood loss, postoperative pain [measured by the visual analog scale, (VAS)], complication rates, and hospital stay duration.

3. Quality Assessment Data: Information from the quality assessment of each study.

Microsoft Excel was used to organize and manage the data collection process.

Statistical Analysis

In conducting the meta-analysis, review manager software and openmeta (Analyst)⁽¹⁵⁾ were used. Both categorical and continuous variables were included in the analysis. The continuous data were presented and compared using the mean difference (MD) along with 95% confidence interval (CI), while the dichotomous data were compared using risk ratios (RR) and a 95% CI. For homogeneous data, a fixed-effects model was employed, while for heterogeneous data, a random-effects model was used. To evaluate the heterogeneity of the studies, the I² statistic and the chi-square tests were conducted, and the values of p<0.1 or I²>50% were considered to indicate significant heterogeneity.

Summary of the Included Studies

Ultimately, we included eleven studies in our analysis: three RCTs^{(6, 16, 17)}, one prospective comparative study⁽¹⁸⁾, and seven retrospective studies^{(4, 19-24)}. All included studies compared the efficacy and safety measures of LESS and CLS for adnexectomy in the presence of benign ovarian lesions. The detailed results of our literature search are illustrated in the PRISMA flow chart (Figure 1). A total of 1.231 women were included in our analysis, 608 in the LESS group and 623 in the CLS group. The mean age of the included cases in the LESS group was 40.1±11.3 years, and the mean age in the CLS was 39.3±11.3 years. The mean BMI in the LESS group was 22.9±4.23, while in the CLS, it was 22.9±4.06. The mean mass size in centimeters was 5±2.8 in the LESS group and 6.1±4 in the CLS group. Tables 1-3 present the characteristics of the involved studies and the demographics of the women included.

The Results of the Quality Assessment

When looking at the results of the quality assessment, the average score was 10.5 on a scale with a maximum score of 14^{(4, 18-24)}. Table 4 can be referenced for a detailed description of all the factors included in the quality assessment. Regarding the randomized studies^{(6, 16, 17)}, all the included studies were properly randomized, although Hoyer-Sorensen et al.⁽¹⁷⁾ and Shin et al.⁽¹⁶⁾ lack sufficient blinding. Therefore, they were found to be at a high risk of both performance and detection bias. Another outlier study, Fagotti et al.⁽⁶⁾ reported proper blinding of the physicians with a low risk of detection bias, as seen in Figure 2.

Analysis of Outcomes

1. Operative Time (Min)

Most of the studies included in our analysis reported the total operative time for both procedures^{(4, 6, 16, 18-24)}. Our analysis revealed that LESS was associated with a longer operative time than CLS [MD=2.96 (-1.97, 7.90), p=0.24], and a moderate amount of heterogeneity was observed (p=0.07); I²=43. We managed the heterogeneity through a sensitivity analysis, resolving it by the exclusion of Lee et al.⁽²⁰⁾. This resulted in [MD=3.52 (-1.01, 8.06), p=0.13] reduced heterogeneity (p=0.14, I²=35%), as seen in Figure 3.

2. Estimated Blood Loss (EBL) (in mL)

Estimated blood loss during the surgery was measured by seven studies^{(4, 6, 18, 19, 21, 22)}. Our pooled analysis revealed that adnexectomy using LESS was associated with a statistically significant reduction in the EBL compared with conventional laparoscopy [MD=-18.62 (-33.83, -3.42), p=0.02]. The analysis showed significant heterogeneity (p=0.01, I²=95%), which could not be addressed (as seen in Figure 4).

3. Length of Hospital Stay (in Days)

The mean hospital stay in the LESS group was 2.6 days, while in the CLS group it was 2.7 days. Our analysis showed that both operations had comparable hospital stay periods [MD=-0.02 (-0.50, 0.47), p=0.95] but significant heterogeneity was present (p=0.01, I²=92%), which we could not solve, as seen in Figure 5.

4. VAS Pain Score 24 hrs After Surgery

This outcome was reported by five studies^{(16-18,21,22)}. There was no significant difference found between the two groups regarding the measured VAS score [MD=0.23 (-0.09, 0.56), (p=0.16)]. Our analysis of the data revealed considerable heterogeneity (p<0.005); I²=74%. The heterogeneity was solved by the exclusion of Shin et al.⁽¹⁶⁾ [MD=0.41 (0.26, 0.56) p=0.01], I²=1%, as seen in Figure 6.

5. VAS Pain Score 6 hrs After Surgery

Both procedures were associated with similar pain scores six hours after surgery [MD=0.15 (-0.04, 0.33), (p=0.12)]. Our analysis of the data was homogeneous (p=0.12), I²=27%, as seen in Figure 7.

6. Analgesic Use

The incidence of requiring analgesia in the postoperative period was significantly lower in the LESS group than in the CLS group. RR=0.47 (0.32, 0.68), p=0.001. The pooled analysis was homogenous (p=023); I²=29%, as seen in Figure 8.

7. Change in Hemoglobin (HGB) Level

The outcome was reported by five studies^{(16, 18, 20-22)}. Both groups were associated with comparable decreases in HGB with a homogenous analysis [MD=-0.11 (-0.26, 0.03) (p=0.14)], as seen in Figure 9.

8. Perioperative Complications

Six of the included studies evaluated the perioperative complications of both procedures. The incidence of perioperative complications was significantly higher in the LESS group than the CLS group [RR=2.236 (1.031, 4.851), p=0.04]. The pooled analysis was homogeneous (p=0.9; I²=0%), as seen in Figure 10.

9. BMI and Previous Abdominal Surgery

We compared the BMI of the included cases, as well as the incidence of previous abdominal surgery, between the two procedures to determine if these factors could have affected the reliability of our analysis. We found that both BMI [MD=-0.07 (-0.48, 0.34), (p=0.74), I²=0%] and the history of previous abdominal surgeries [RR=1.16 (0.97, 1.38), (p=0.10), I²=0%] were nearly identical between the two groups, as seen in Figures 11 and 12.

In our study comparing LESS and CLS in adnexectomy for benign adnexal disease, we focused on several efficacy and safety outcomes. As for the difference in operative time, LESS required slightly more time than CLS. The EBL was significantly reduced in the LESS compared with CLS. Hospital stays and VAS pain scores at 24 and 6 hours were similar between the two techniques. Analgesic use postoperatively was significantly lower in the LESS group. The change in HGB levels was comparable between the groups. However, the incidence of perioperative complications was significantly higher in the LESS group. This comprehensive comparison highlights that while LESS may offer benefits such as reduced blood loss and analgesic use, it also presents challenges including longer operative times and higher complication rates. This may challenge the feasibility of LESS in some situations.

Salpingectomy using LESS was first performed by Ghezzi et al.⁽²⁵⁾ in 2005, but has not been completely implemented, likely due to the technical difficulties encountered. Innovations in techniques and devices have expanded single port applications to various gynecological procedures⁽²⁶⁾. Some of the limitations of LESS include reduced triangulation, instrument interference, and reduced visualization. Considering these limitations, this consideration may explain why the incidence of complications after LESS adnexectomy was higher than with CLS as reported by our analysis. These issues can make it more difficult for surgeons compared to standard laparoscopy, and present a steeper learning curve for surgeons in training⁽²⁷⁾. Therefore, patient selection may be key in certain circumstances⁽²⁸⁾. Patients with smaller adnexal masses, normal BMI and without an extensive history of abdominal surgery may be preferred⁽²⁹⁾. However, the current study did not identify significant differences in the above patient characteristics between the LESS and conventional laparoscopy groups, and therefore did not find evidence of patient selection bias affecting results. We performed an analysis comparing BMI and history of previous operations, ensuring there was no significant baseline difference between the LESS and CLS groups. This indicates that disease and patient features do not necessarily limit the applicability of LESS⁽²⁶⁾.

The most recent meta-analysis on this topic, Lin et al.⁽³⁰⁾, also found an increase in perioperative complications in the LESS group. This study differed from our study in that it was compelled to include ovarian cystectomy surgeries because of the limited number of studies available at that time dealing with adnexectomy. The fact that our study also shows an increase in perioperative complications seems to convincingly suggest that LESS is more dangerous than CLS for adnexectomy. Furthermore, it is possible that more of the risk that was found in Lin et al.⁽³⁰⁾ came from the adnexectomy studies than from the cystectomy studies.

In addition to increased complications, LESS was found to have a longer operative time compared to CLS. Long operative time results in increased time spent under pneumoperitoneum and anesthesia and raises the risk of postoperative complications including paralytic ileus⁽³¹⁾. Jeung et al.⁽³²⁾ concluded that it was significantly more common for a postoperative ileus to occur in patients who underwent laparoendoscopic single port hysterectomy with operative times >150 minutes, whereas no ileus occurred during surgeries lasting ≤150 minutes. While this topic remains controversial and requires further investigation, it suggests a potential relationship between ileus and LESS.

Another point of view was reported in a recent case series by Fagotti et al.⁽⁶⁾ and Escobar et al.⁽³³⁾, who sought to establish the feasibility of LESS for performing salpingo-oophorectomy in patients with BRCA gene mutations for the purpose of cancer risk reduction. Regarding LESS, they found the surgical competency can be attained in 10-15 cases, with a mean operative time of 38.1 minutes. This indicates that LESS may be as safe or safer than CLS in certain patient subgroups.

Study Limitations

This meta-analysis has several limitations. We could only find three RCTs, and they had a relatively small sample size. This creates a ROB. To overcome this, we included RCTs and non-RCTs in our study to achieve a larger sample size and greater statistical power. The resulting evidence was then highly heterogeneous, likely secondary to the differences concerning the tumor types, their size, the age of the patient, indications for surgery, and criteria used for matching. Unfortunately, we could not subgroup by the histologic type of ovarian mass, as very few studies gave data on this parameter.

Compared with CLS, LESS needed more operative time, but offered significantly less estimated blood loss. Hospital stays and VAS pain scores at 6 and 24 hours postoperatively were similar between the two techniques. LESS resulted in significantly lower postoperative analgesic use and comparable changes in HGB levels. However, the incidence of perioperative complications was higher in the LESS group. These findings challenge the feasibility and safety of LESS for adnexectomy when compared to CLS.

Acknowledgements

The Marchand Institute for Minimally Invasive Surgery would like to acknowledge the efforts of all the students, researchers, residents, and fellows at the institute who put their time and effort into these projects without compensation, only for the betterment of women’s health. We firmly assure them that the future of medicine belongs to them.

Authorship Contributions

Surgical and Medical Practices: G.J.M., A.Az., Concept: G.J.M., Design: G.J.M., B.H., Data Collection or Processing: H.U., A.A., D.G., B.H., K.R., M.D., Analysis or Interpretation: K.R., A.Az., Literature Search: H.U., A.A., D.G., B.H., K.R., M.D., Writing: G.J.M.

Conflict of Interest: No conflict of interest was declared by the authors.

Financial Disclosure: The authors declared that this study received no financial support.