Ultra-minimally invasive surgery in gynecological patients: a review of the literature

In the last decade, Ultra-minimally invasive surgery (UMIS) including both minilaparoscopic (MH) and percutaneous (PH) endoscopic surgery achieved widespread use around the world. Despite UMIS has been reported as safe and feasible surgical procedure, most of the available data are drawn from retrospective studies, with a limited number of cases and heterogeneous surgical procedures included in the analysis. This literature review aimed to analyze the most methodologically valid studies concerning major gynecological surgeries performed in UMIS. A literature review was performed double blind from January to April 2021. The keywords ‘minilaparoscopy’; ‘ultra minimally invasive surgery’; ‘3 mm’; ‘percutaneous’; and ‘Hysterectomy’ were selected in Pubmed, Medscape, Scopus, and Google scholar search engines. PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines were followed for the drafting of the systematic review. The systematic literature research provided 298 studies, of which 9 fell within the inclusion criteria. Two hundred ninety-six total patients were included, 148 for both PH and MH groups. Median age (48 years), BMI (24 kg/m2), OT (90 min), EBL (50 ml), time to discharge (1 day), self scar evaluation (10/10), and VAS (3/10) were reported. The most frequent intraoperative complication in both the PH and MH groups was surgical bleeding. The UMIS approaches were feasible and safe even for complex gynecological procedures. Operative times and complications were superimposable to the “classical” minimally invasive approaches reported in the literature. The reported results apply only to experienced surgeons.

Compared to "traditional" surgical techniques, the reduced number and size of laparoscopic trocars was related to superior aesthetic results and pain tolerance while maintaining the same surgical safety [7][8][9].
Technological advancement has led to an increasing tendency to reduce the invasiveness of surgical experience [10][11][12], resulting in the establishment of a new branch of MIS, namely ultra minimally invasive surgery (UMIS), which includes both minilaparoscopic (3 mm trocar) and percutaneous endoscopic surgery [13,14].
Suppose this trend towards a growing minimally-invasiveness is globally accepted and continuously developed in benign surgery. Minimal-invasiveness procedures also included another gynecologic area, for example, the hysteroscopic system that transitioned from a traditional approach [15,16] to a virtual endoscopy that allows uterine cavity visualization without an invasive procedure utilizing a 3-D reconstruction [17][18][19].
In that case, the application of MIS in the management of gynecological malignancies must be carefully proposed in selected cases and paying attention to oncological adequacy [20][21][22][23].
The minimally invasive approach during endometrial cancer surgical staging represents the standard of care supported by the evidence of the international guidelines [24][25][26][27].
Several studies [39][40][41] observed UMIS benefits in terms of shorter hospital stay, better aesthetic outcomes, less postoperative discomfort, and increased patient satisfaction compared to traditional laparoscopic or robotic surgery.
However, most of the available data come from retrospective studies, with a small number of enrolled patients and a range of different surgical procedures included in the same research.
This literature review analyzed the most methodologically valid studies concerning major gynecological surgeries performed in UMIS. Additionally, the disadvantages and advantages of ultra-minimally intrusive techniques have been outlined.

Materials and methods
Two authors performed a literature review double-blind from January to April 2021.
A third author oversaw the selection of articles by the two previous authors.
All studies in English-language, with more than 15 cases reporting "complex gynecological procedures", and performed with UMIS technique were included in the analysis.
By "complex gynecological procedures" was meant interventions included at least hysterectomy with bilateral salpingo-oophorectomy with or without pelvic lymph node dissection.
Both MH and PH have been included in the UMIS group. The minilaparoscopic surgical technique involved the placement of a 10 or 5 mm transumbilical trocar and three 3 mm ancillary trocars in the suprapubic area and the right and left flank, respectively.
The percutaneous surgical technique involved one 10 or 5 mm transumbilical optic access, one 5 mm suprapubic trocar, and two needlescopic accesses in the right and left flank.
Author, year of publication, type of device, age, body mass index (BMI), operating time (OT), estimated blood loss (EBL), day of discharge, scar patient assessment, pain visual analog scale (VAS), complication, and the type of the performed procedure were collected for each article.
Patient scar rating was determined by the patient's subjective assessment on a scale from 0 to 10.
The VAS scale was defined as a visual pain scale ranging from 0 to 10. Complications were classified according to the Clavien-Dindo definition.
All articles not falling within the inclusion criteria, with missing data, or not related to the objective of this review were excluded.
PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) [46] guidelines were followed to draft this systematic review of the literature.
Ten articles were excluded because the cohort series was less than 15 patients. Eighteen case reports and 4 studies containing redundant data were excluded. One hundred and fifty-three studies did not report "complex gynecological procedures" and 111 articles did not adhere to the purpose of this review. The study selection flow chart is shown in Fig. 1. Of the included studies, 6 were retrospective in nature, one prospective, and 2 studies were randomized clinical trials.
Three studies included patients with benign disease, 4 studies involved patients with a benign disease or earlystage endometrial cancer, and 2 articles exclusively analyzed patients with malignant conditions (one included patients with early-stage endometrial cancer and the other one patients with early-stage cervical cancer).
After EC diagnosis, total hysterectomy with or without salpingo-oophorectomy were performed for all benign conditions, while nodal dissection was pursued in malignant cases [55].
Two hundred ninety-six total patients were included, 148 for both PH and MH groups.
As shown in Table 3, 21 total complications were reported, 2 intraoperative and 6 postoperative in the PH group, and 5 intraoperative and 8 postoperative in the MH group.
The most frequent intraoperative complication in both the PH and MH groups was surgical bleeding (6 cases out of 7 total intraoperative complications). The most commonly reported postoperative complications were bleeding (3 cases), fever (3 cases), and urinary infection (2 cases). All complications were managed with conservative treatment and were classified as Dindo grade 1 or 2.

Discussion and evidence synthesis
Based on the main findings of the literature we stratified the discussion by focusing on the strengths and weaknesses of the UMIS technique.

Cosmetic outcomes
Since its introduction in 1998, UMIS was aimed to reduce the size of abdominal scars while simultaneously increasing the quality of life of patients [56].
According to subjective patient perception [57], there is no doubt that the decreased width of the surgical scar in both the PH and the MH groups resulted in superior aesthetic outcomes.
The percutaneous method, in particular, is regarded as the greatest example of "scarless surgery," with the surgical scar reported on postoperative day 30 as scarcely discernible [58].
In our analysis, all patients showed an extremely high level of cosmetic satisfaction.
Similar results were also obtained for other general and urologic surgeries [59,60]. Furthermore, as reported by David et al. [61], the same excellent cosmetic outcomes could be achieved for complex upper abdominal procedures.
The effects of abdominal surgical scars had received less attention than those of face surgical scars [36,54], even though they might have significant physical and psychological consequences [44,62].
Furthermore, further clinical studies are required to evaluate and further analyze the psychological influence of the abdominal scar on patients' quality of life [63,64] in this context.

Pain relief
Excellent pain management was noted in the patients included in the analysis, with a median "mild pain" reflected at the VAS score (VAS score 1-3 defines "mild pain"). These findings are supported by a large amount of scientific research, which includes both the UMIS and the MIS approaches [65][66][67][68].
Donnez et al. [69] found a mean VAS score of 4 (3.5 2.6) at 1 h following surgery in MIS hysterectomy patients.
Furthermore, as hypothesized, the UMIS technique demonstrated a significant increase in pain management with fewer analgesics needed in various types of surgical   procedures when compared to their laparotomic equivalent [70][71][72] (Figs. 2 and 3). Indeed, the progressive reduction in the skin incision size is immediately mirrored in the decrease of parietal neuromuscular injury with concomitantly reduced incisional pain..
As reported by Cianci et al. [47], referred pain was better in the percutaneous approach than in the minilaparoscopic approach (VAS score 3 vs 5 at 24 h after surgery, respectively).
Overlapping results were also shown by Perrone et al. [73] in a multicentric cohort study comparing percutaneous with "classical laparoscopic surgery".
Finally, since no clinical trials on this topic are currently available, we can conclude that both the percutaneous and minilaparoscopic approaches represent an opportunity to improve patient-referred pain compared to the "classical" minimally invasive approaches in selected cases and experienced hands (Tables 4, 5, 6, and 7).

Surgical outcomes
In our series, all the papers analyzed showed a comparable median OT, EBL, complication rate, and type of procedures between MIS and UMIS.  Furthermore, even in the setting of advanced surgical procedures, such as pelvic lymphadenectomy, median OT and complications were superimposable to that reported for the standard laparoscopic approach [74][75][76][77].
However, all the analyzed reports were referred to highvolume third-level centers for gynecological malignancies, making more difficult the generalization of the obtained results.
Another technical aspect that contributes to the excellent surgical outcomes is the maintenance of the standard laparoscopic triangulation even in the UMIS approach.
Usually, two needlescopic instruments in the left and right flank (2.9 mm of Percuvance ™ or 2.4 mm of Mini-Grip™) and one 5 mm operative suprapubic trocar are positioned in percutaneous approach while three 3 mm trocar are placed, in the same positions, during minilaparoscopic approach [78]. In this scenario, percutaneous and minilaparoscopic surgery may be more feasible and manageable than other single port MIS in which triangulation is lacking [79].

Manipulating tissue and coagulation
According to several authors, the fundamental limitation of percutaneous instrumentation is the limiting of tissue mobilization due to the shaft's diameter [43]. As a result, percutaneous tools may buckle when treating heavy structures such as massive ovarian masses. In addition, the inefficient lever effect is amplified by the abdominal wall's high resistance, which amplifies the instrument's flexion.Even the small size of the instrument's jaw could negatively impact the correct mobilization of enlarged uteri (> 250 g) or adnexal masses [80,81] while determining an increased risk of tissue laceration [82].
Finally, as pointed out by several authors, the lack of energy in percutaneous instruments makes multifunction devices recommended, even in cases with relatively low technical difficulty [13,43].
Consequently, if, on the one hand, an excellent surgical performance with reduced operating times was guaranteed through the use of an integrated energy device, on the other, costs were increased.

Feeling in managing tissues
Gueli Alletti et al. [42] has highlighted the lack of tissue manipulation feeling as the primary constraint of percutaneous endoscopic instrumentation in a research including 382 patients who received "complex gynecological procedures.".
Needleoscopic tools are inserted directly into the abdominal cavity losing the smooth glide of the instrument inside the trocar. In this way, the laparoscopic instrument rubbed with all components of the anterior abdominal wall (skin, subcutaneous fat, fascia, muscles, and peritoneum).
This pitfall together with the small and sharp operating tip makes tissue manipulation less sensitive by increasing the risk of tissue tearing if excessive traction is applied [48].
This limitation was particularly evident in the manipulation of soft tissues, such as in lymph node grasping during nodal dissection in endometrial cancer cases [42].

Review strengths and limitations
There were several limits to our review. First of all, we only considered studies performed at third-level oncological centers. It should be noted that all of the studies included were retrospective in design, and no control groups were included. At the least, the number of described case series is limited. The primary strength of our review was the only complex gynecological surgeries inclusion, hence minimizing the selection bias.

Conclusions
Even for complicated gynecological procedures, the UMIS techniques proved viable and safe.
Operation durations and problems were significantly decreased compared to "classical" minimally invasive procedures mentioned in the literature.
Funding Open access funding provided by Università degli Studi della Campania Luigi Vanvitelli within the CRUI-CARE Agreement.

Availability of data and material On request.
Code availability Not applicable.

Declarations
Conflict of interest None of the authors have a conflict of interest to disclose.

Ethics approval Not applicable.
Informed consent Not applicable. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http:// creat iveco mmons. org/ licen ses/ by/4. 0/.