Impact of uterine weight on surgical outcomes in robotic hysterectomy: An ambispective analysis.

Hysterectomy is the most common surgery performed on women, with prevalence in India being around 11.35%, the main indications being benign conditions like abnormal uterine bleeding and fibroids.[ 1 ] The prevalence of minimally invasive techniques has risen due to evidence of better results in comparison to abdominal methods.[ 2 ] Current guidelines advocate the utilisation of minimally invasive approaches in benign hysterectomy when indicated.[ 3 ] Since its inception in 2001, the adoption of robotic-assisted laparoscopic hysterectomy has been on the rise, attributed to benefits such as enhanced three-dimensional visualisation, increased magnification and better ergonomics.[ 4 ] Studies have shown that operative results are influenced by uterine weight, with increasing complications, blood loss and operative time with more uterine weight.[ 5 ] Nevertheless, the correlation between surgical outcomes and uterine size does not exhibit a linear pattern. Up to a specific uterine size, there is no apparent effect on surgical performance and technical challenges, and the disparity in surgical outcomes remains modest. Beyond a certain threshold of uterine size, minimally invasive surgeries for hysterectomy might be difficult, making laparotomy a safer surgical option for larger uteri.[ 6 ] In this study, we analysed the influence of uterine size on robotic hysterectomies, categorising uterine size in increments of 250 g, and sought to determine the application of robotic surgery in the context of hysterectomy. This study aimed to assess the impact of uterine weight on surgical outcomes of robotic hysterectomy performed for benign indications.

This was an ambispective record analysis conducted at a tertiary care centre from March 2018 to September 2022 after obtaining ethical clearance from the institute’s ethics committee. Records of the cases undergoing robotic hysterectomy for benign pathology were obtained from the hospital database and were kept confidential in accordance with institutional policies on subject privacy and data, and records were not used for any purpose other than conducting the study. Retrospective data were obtained from March 2018 to February 2022. Prospective data were obtained from February 2022 to September 2022. Data were extracted from the e-hospital database, operative notes, institutional robotic operation room database and pathology records. The present study included cases of undergone robotic hysterectomy with or without salpingectomy (excluding other simultaneous procedures) for benign causes and availability of completed operation notes, while exclusion criteria included surgeries for malignant disease of the uterus, cervix or ovaries/adnexa, abdominal, laparoscopic and vaginal hysterectomies and cases with coagulation disorders. Cases with medical records lacking vital information were excluded. Cases were stratified into three groups based on the weight of the uterine specimen measured intraoperatively: 500 g. All surgeries were performed using the da Vinci Xi robotic system. A 12-mm camera port was inserted, following which three or four 8-mm trocars were placed. Hysterectomy was performed using fenestrated bipolar (for cauterising the tissue) and monopolar scissors (for cauterising and cutting tissue). The specimen was delivered vaginally; larger uteri were extracted either vaginally by coring or by manual in-bag morcellation through a mini-laparotomy incision. Vaginal cuff closure was done robotically with either barbed or polyglactin suture in a running fashion. Primary outcome measures included total operative time, while secondary outcomes included estimated blood loss (EBL), the impact of body mass index (BMI) on operative time, length of hospital stay and quality of life (QOL) at post-operative day 7 assessed using the World Health Organization Quality of Life Brief (WHO-QOL-BREF) questionnaire (permission reference ID: 387410). The WHO-QOL-BREF seeks to appraise an individual’s health concerns amongst the four domains of physical, psychological, social and environmental health. The raw scores were calculated for each domain and then converted into transformed scores (0–100). This was assessed only prospectively recruited cases. Total operative time was defined as the time from incision to the skin closure time. This included time for docking of the robot, completion of hysterectomy till colpotomy, specimen extraction (either vaginally or by mini-laparotomy incision), closure of vaginal vault and closure of skin incisions. Docking time was noted as the time taken to move the robot into the surgical field and insert the three robotic arms into the respective ports, while console time was defined as the time the surgeon took to complete a hysterectomy while operating on the robotic console. Vault closure time was defined as the time taken to close the vaginal vault with either standard polyglactin 910 sutures or unidirectional barbed sutures. Data analysis was performed using the Statistical Package for the Social Sciences (SPSS) software, IBM manufacturer, Chicago, USA, version 25.0. The association of the variables, which were quantitative in nature was analysed using the Kruskal–Wallis test (for not normally distributed data). The association of the variables, which were qualitative in nature, were analysed using Fisher’s exact test. The Spearman rank correlation coefficient was used to correlate the weight of the uterus and BMI with operating time. Univariate linear regression was used to find out factors affecting operating time. For statistical significance, P < 0.05 was considered statistically significant.

A total of 322 cases underwent robotic hysterectomy during the study. Sixteen cases were excluded [ Figure 1 ]. Thus, 306 cases were included in the final analysis, with 265 retrospective cases and 41 cases recruited prospectively. Based on the intraoperative weight of the uterine specimen, 76.47% of cases ( n = 234) had uterine weight 500 g. The mean age of the study population was 45.24 ± 6.5 years, while the mean BMI was 26.44 ± 4.38 kg/m 2 . Table 1 shows that the baseline characteristics between the groups stratified based on uterine weights were comparable. Abnormal uterine bleeding (73.86%) was the most common indication for robotic hysterectomy for the study population [ Table 2 ], while final histopathology revealed the most common pathology to be leiomyoma (55.88%), followed by adenomyosis (37.91%) [ Table 3 ]. Study flow diagram. POD: Post-operative day Comparison of baseline characteristics between groups *Fisher’s exact test, ‡ Kruskal–Wallis test. Data presented as mean±SD, n (%). SD: Standard deviation, BMI: Body mass index Indication for hysterectomy Final uterine histopathology of the cases The docking time was comparable between the groups. Console time was significantly lower in the uterine weight <250 g group compared to the group with 250–500 g ( P = 0.044), while the total operative time was significantly lower in the 500 g ( P = 0.003). Although the EBL was comparable between the groups, the fall in haemoglobin (Hb) level and need for intraoperative and post-operative blood transfusion were significant in the 500 g (0.87 ± 0.85 vs. 1.46 ± 1.03, P = 0.01 and 1.28% [ n = 3] vs. 12.50% [ n = 2], P = 0.034, respectively) [ Table 4 ]. Comparison of operative characteristics based on uterine weight stratification *Fisher’s exact test, † Kruskal–Wallis test data presented as mean±SD, n (%). SD: Standard deviation The length of hospital stay was 4.15 ± 1.25 days in the 500 g group: 5.06 ± 1.06 days ( P = 0.002), and it was 4.43 ± 0.99 days in the 250–500 g group. The intraoperative and post-operative complications were similar amongst the groups [ Table 5 ]. QOL was assessed for 41 cases recruited prospectively, and cases showed no difference in the physical, psychological, social and environmental QOL domains [ Table 6 ]. Comparison of intra- and post-operative complications between the groups *Fisher’s exact test Quality of life assessment (World Health Organization-Quality of Life Brief questionnaire) *Kruskal–Wallis test. WHO-QOL BREF: World Health Organization Quality of Life Brief On univariate analysis, no correlation was seen between operating time with BMI with a correlation coefficient of 0.009. A non-significant mild positive correlation was seen between operating time with the uterine weight with a correlation coefficient of 0.09. On performing univariate regression, the uterine weight was a significant predictive factor for operating time. With the increase in uterine weight by 1 g, operating time significantly increased by 0.04 min. That is, for an increase in the uterine weight by 100 g, operative time increased by 4 min [ Figure 2 ]. (a) Correlation of uterine weight with operating time. (b) Correlation of body mass index with operating time

The present study underscores the influence of uterine weight on robotic hysterectomy outcomes, revealing increased operative times and post-operative Hb drop for uteri over 500 g. Despite these challenges, complications were not significantly affected by uterine size. The study emphasises the importance of meticulous surgical planning for larger uteri and suggests potential areas for further investigation, such as pre-operative measurements to refine surgical strategies. There are no conflicts of interest.

Studies in the published literature have demonstrated a connection between uterine size and operative time, as well as EBL in minimally invasive procedures.[ 6 ] However, it remained unclear at what specific uterine size robotic hysterectomy becomes clinically challenging. The present study is one of the few studies that comprehensively evaluate surgical outcomes of robotic hysterectomy, stratifying the analysis based on uterine weights. We found that cases with the uterine weight of more than 500 g had higher console time, total operative time and higher fall in post-operative Hb levels. However, the occurrence of complications, both intraoperative and post-operative, remained unaffected by uterine size. In the present study, the median operative times were 76 min (500 g). Operative time was significantly different across uterine weights. This was in agreement with previous studies.[ 6 7 8 9 ] This can be attributed to two causes: first, greater difficulty in manipulation of larger uteri, and consequently, a narrower surgical field. Second, large myomatous uteri were removed by in-bag morcellation or coring of the specimen, which protracted the extraction time (either vaginally or through mini-laparotomy). There was no significant difference between the docking times amongst different uterine weights. Docking time is mainly dependent on factors affecting operating room efficiency and is largely independent of patient factors like uterine weight. Few cases are required for docking times to plateau, and docking time does not seem to have much bearing on the total operative time. Hence, the difference in the console time was primarily responsible for higher operating time in cases with uterine weight of more than 500 g. Previous reports suggest that EBL is significantly higher amongst patients with heavier uteri.[ 6 8 9 ] In Tyan et al .’s study, EBL was 35% and 156% more for patients with uterine weights 500–1000 g and >1000 g, respectively, compared to patients with uterine weights <250 g.[ 9 ] However, Perutelli et al . studied the drop in Hb along with blood loss, and both were not found to be significantly different between uterine weights; this was consistent with the present study suggesting that the drop in Hb could be a more objective way of assessing that estimating blood loss intraoperatively.[ 7 ] Consistent with the published literature, no difference in the complications was noted on stratification based on uterine weight. As the present study was conducted in a hospital with most patients coming from hilly terrain, many patients preferred to stay longer in the hospital. As such, our actual length of hospital stay was longer compared to previous studies carried out in developed countries. There is conflicting literature regarding the relationship of BMI with operative time, ranging from a positive association to none at all.[ 10 11 12 ] Perutelli et al . reported that operative time is influenced by factors such as uterine weight, previous surgeries and the BMI of the patient. Furthermore, it may be partially influenced by the route for removal of the uterus. They reported that for every 1 kg/m 2 increase in BMI, the operative time increased by 1.40 min. However, a higher BMI was not related to higher chances of conversion or greater blood loss, proving robotic hysterectomy to be a good option for obese women.[ 7 ] One of the strengths of the study is that none of the patients received gonadotropin-releasing hormone analogues preoperatively, which may have an effect on uterine weight. To our knowledge, this is the first study evaluating QOL after robotic hysterectomy based on stratification by uterine weights. Our study had an ambispective design, while most of the studies in the published literature are retrospective. One of the drawbacks is the lack of quantification of morcellation time or time taken for extraction of the uterine specimen, which contributes considerably to the total operative time. Another drawback is that the uterine weight used for stratification was measured post-specimen retrieval. Hence, we suggest further studies be done using measurements that can be obtained preoperatively, like sonographic uterine size or volume, which will help in guiding the use of robotic surgery for enlarged uteri, and its implication on the surgical outcomes may be studied.