Hayoung Lee; Yong Sik Yoon; Young Il Kim; Min Hyun Kim; Jong Lyul Lee; Chan Wook Kim; In Ja Park; Seok-Byung Lim

doi:10.3393/ac.2025.00227.0032

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Original Article Minimally invasive surgery Comparative perioperative outcomes of articulated versus conventional straight devices in laparoscopic low anterior resection: a propensity score–matched analysis: Hayoung Lee^1,2, Yong Sik Yoon¹, Young Il Kim¹, Min Hyun Kim¹, Jong Lyul Lee¹, Chan Wook Kim¹, In Ja Park¹, Seok-Byung Lim¹; Annals of Coloproctology 2025;41(5):434-442.
DOI: https://doi.org/10.3393/ac.2025.00227.0032
Published online: October 16, 2025

¹Department of Colon and Rectal Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea

²Department of Surgery, Kyung Hee University Hospital at Gangdong, Kyung Hee University College of Medicine, Seoul, Korea

Correspondence to: Yong Sik Yoon, MD, PhD Department of Colon and Rectal Surgery, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Korea Email: yoonys@amc.seoul.kr

• Received: March 1, 2025 • Revised: June 7, 2025 • Accepted: June 7, 2025

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Abstract
INTRODUCTION
METHODS
RESULTS
DISCUSSION
ARTICLE INFORMATION
SUPPLEMENTARY MATERIALS
REFERENCES

Abstract

Purpose
Laparoscopic low anterior resection for rectal cancer is technically challenging due to the precision required for mesorectal excision. Articulated instruments were developed to improve precision and oncological safety over conventional instruments. This study compares their perioperative outcomes.
Methods
A retrospective cohort study of 432 patients with colorectal cancer who underwent low anterior resection between August 2022 and February 2024 applied propensity score matching to minimize selection bias. Primary endpoints were circumferential resection margin (CRM), distal resection margin (DRM), and harvested lymph nodes count. Secondary outcomes included postoperative complications.
Results
Following propensity score matching, 84 matched pairs were analyzed. Most patients achieved CRM negativity (>1 mm), with CRM ≥10 mm in 67.9% of the articulated group and 59.5% of the conventional group (P=0.613). Median (interquartile range, IQR) lymph nodes harvests were comparable (20 [14–26] vs. 18 [14–22], P=0.147). The articulated group had a significantly longer DRM (30.0 mm [IQR, 18.0–40.0 mm] vs. 24.0 mm [IQR, 12.0–34.2 mm], P=0.008) and the median operation time (111.0 minutes [IQR, 95.8–125.2 minutes] vs. 99.5 minutes [IQR, 72.0–119.8 minutes], P=0.009). Estimated blood loss, open conversion rates, and postoperative complications, including leakage (7.1% vs. 8.3%, P>0.999) and surgical site infections, (15.5% vs. 9.5%, P=0.383), showed no significant differences.
Conclusion
Articulated laparoscopic instruments demonstrated comparable safety and feasibility to conventional instruments but offered no significant clinical or oncological benefits beyond a longer DRM. Larger studies are needed to evaluate their value in laparoscopic rectal surgery.
Keywords: Colorectal surgery; Rectum resection; Laparoscopy; Articulated device

INTRODUCTION

The adoption of laparoscopic techniques in colorectal cancer surgeries has largely replaced elective open procedures, driven by advantages such as smaller incisions, lower surgical site infection (SSI) rates, reduced blood loss, and comparable oncological outcomes [1–3]. Among these, laparoscopic low anterior resection (LAR) for rectal cancer presents distinct challenges due to the technical demands of total mesorectal excision (TME), a critical step shown to improve oncological outcomes by lowering local recurrence rates [4, 5]. However, TME requires precise dissection within the restricted pelvic space, necessitating careful navigation around vital structures, including urogenital organs, nerves, and blood vessels, thereby increasing the risk of intraoperative complications and postoperative morbidity [6]. Conventional laparoscopic instruments, limited by their straight and rigid design, can intensify these challenges and contribute to surgeon fatigue during complex procedures [7, 8]. These limitations have led some early studies to report poorer outcomes for laparoscopic TME compared to open surgery, particularly in achieving negative circumferential resection margins (CRMs) [7, 9].

Robotic surgery emerged to address the limitations of conventional laparoscopic techniques, offering the advantages of minimally invasive surgery alongside advanced features such as three-dimensional visualization, hand tremor correction, and articulated instruments that replicate the dexterity of the human hand [1]. These advantages are particularly beneficial in the confined pelvic space during TME. However, the widespread adoption of robotic systems remains constrained by their high acquisition and maintenance costs, limiting accessibility even in major medical centers and imposing a significant economic burden on patients [10].

Articulated laparoscopic instruments were developed to provide robotic-like articulation, while maintaining cost-effectiveness. Emerging research suggests these devices hold promise in laparoscopic surgery. Recent studies report that using ArtiSential articulated instruments (LivsMed) in laparoscopic TME significantly reduces blood loss while achieving operative times comparable to robotic surgery [11].

Despite these promising results, it remains essential to determine whether articulated instruments truly enhance the precision and oncological safety of TME over conventional instruments, particularly in facilitating secure pelvic dissections, an ongoing challenge when comparing laparoscopic and open approaches. To address this, the present study employed a propensity score–matched analysis to compare the perioperative outcomes between conventional and articulated laparoscopic instruments. Evaluated outcomes included CRM, distal resection margin (DRM), lymph node harvest, and postoperative complications.

METHODS

Ethics statement

This study was approved by the Institutional Review Board of Asan Medical Center, with a waiver of informed consent (No. 2024-1244). All procedures adhered to the principles of the Declaration of Helsinki. The study followed the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) guidelines (Supplementary Table 1) [12] and modified recommendations for propensity score analysis [13].

Patients

This study analyzed data from patients who underwent elective, curative laparoscopic LAR for histologically confirmed colorectal cancer between August 2022 and February 2024 (Fig. 1). Eligible participants were aged 18 to 80 years and underwent anastomosis using circular staplers. A total of 487 patients underwent LAR during the inclusion period. Among 487 patients who underwent laparoscopic LAR during the study period, 55 were excluded for the following reasons: manual anastomosis such as coloanal anastomosis (n=20), pathologic stage IV disease (n=28), and nonadenocarcinoma histology including neuroendocrine tumors (n=7). These criteria were applied to ensure consistency in intra-abdominal surgical resection extent and histologic subtype. The final cohort included 432 patients, of whom 86 underwent surgery using articulated instruments and 346 with conventional straight instruments. Seven colorectal specialists, each with experience exceeding 50 conventional laparoscopic LAR cases [14] and currently performing over 50 LAR procedures annually, conducted the surgeries. Data were comprehensively gathered from hospital medical records, including operative notes, postoperative ward records, outpatient visits, and emergency department encounters.

Study groups and surgical procedures

This retrospective study compared 2 types of laparoscopic instruments, selected according to the preferences of 7 expert colorectal surgeons. Three of these surgeons predominantly used the articulated devices. In the articulated instrument group, surgeons employed ArtiSential instruments. All patients underwent standardized LAR with TME or tumor-specific mesorectal excision, based on lesion location and tumor extent. In the articulated instrument group, both the ArtiSential grasper and endobovie were used simultaneously with both hands during the pelvic dissection phase of TME. These instruments were selectively employed to improve access and precision in narrow pelvic cavities, rather than throughout the entire procedure (Fig. 2). Trocar placement followed a standardized approach identical to that used in conventional laparoscopic LAR (Fig. 3). A 12-mm umbilical camera port and one or two 5-mm assistant trocars were placed on the left side of the abdomen. For the operator, a 12-mm trocar was used in the right lower quadrant, and either a 5- or 8-mm trocar was placed in the right upper quadrant, depending on whether conventional or articulated instruments were used. Specifically, an 8-mm trocar was used in the right upper quadrant for the articulated group to accommodate the ArtiSential device, as only 8-mm instruments were available during the study period. For patients who underwent LAR, Foley catheters were routinely removed on postoperative day 3.

Data collection

Data collection included baseline characteristics, clinical features, pathological outcomes, and 30-day postoperative surgical outcomes. Demographic variables recorded were age at the time of surgery, sex, American Society of Anesthesiologists (ASA) physical status, and body mass index (BMI). Clinical factors associated with the complexity of TME were also assessed, including tumor location relative to the peritoneal reflection categorized as above or below, preoperative clinical stage, preoperative chemoradiation (PCRT) therapy status, and preoperative bowel obstruction. Preoperative obstruction was defined as either partial obstruction (preventing the passage of a conventional endoscope) or complete clinical obstruction. Intraoperative variables included open conversion rates, estimated blood loss (EBL) categorized as <10, 10–100, or >100 mL, total operative time, and stoma diversion rates. Pathological outcomes assessed were CRM status, the number of lymph nodes harvested, and DRM length. Short-term postoperative complications recorded within 30 days included anastomotic leakage, postoperative bleeding, acute urinary retention (AUR), ileus, SSI, intra-abdominal hematoma, hospital readmission, and reoperation rates.

Endpoints and definitions

The primary endpoints of this study focused on evaluating the quality of mesorectal excision, assessed through CRM status, the number of lymph nodes harvested, and DRM length. At our institution, CRM documentation in pathology reports varied, with some cases providing categorical descriptions (e.g., involvement <10 mm), precise measurements, or, in some cases, lacking assessment entirely. To standardize analysis, CRM was recategorized into 3 groups: abutment (CRM <1 mm, also classified within the <10 mm category), ≥10 mm, and not assessed. We selected the CRM ≥10 mm as a representative indicator of resection quality and designated it as the primary endpoint for comparison between groups. This threshold was chosen based on previous studies demonstrating its association with improved long-term oncologic outcomes, including better cancer-specific survival and reduced local recurrence rates [15, 16]. In contrast, DRM was consistently reported as a continuous variable in millimeters.

Secondary endpoints comprised postoperative complications occurring within 30 days of surgery, with particular attention to AUR and anastomotic leakage. Anastomotic leakage was defined and graded according to the International Study Group of Rectal Cancer (ISREC) guidelines [17], characterizing leakage as any communication between the intraluminal and extraluminal compartments. In patients with stoma diversion, leaks detected within 60 days postoperatively were included to account for the protective effect of the stoma. AUR was defined as reinserting a Foley catheter during hospitalization or within 30 days postoperatively during outpatient follow-up. Anastomotic bleeding was defined as postoperative hematochezia requiring blood transfusion or in-hospital intervention. Ileus was characterized by dietary restriction lasting more than 2 days or necessitating Levin tube insertion. SSIs were classified according to the diagnostic criteria established by the National Healthcare Safety Network guidelines, updated by the US Centers for Disease Control and Prevention (CDC) in January 2024 [18]. Reoperations and hospital readmissions within 30 days postoperatively were recorded regardless of cause. All complications were graded using the Clavien-Dindo classification system to assess severity [19].

Statistical analysis

To compare the outcomes between the 2 groups, appropriate statistical tests were employed based on variable types. Continuous variables were analyzed using Student t-test, while categorical variables were compared using the chi-square test or Fisher exact test. Propensity score matching (PSM) was performed to minimize selection bias and control for confounding. Propensity scores were calculated using logistic regression analysis, incorporating preoperative variables affecting the quality and technical difficulty of laparoscopic TME, including age, sex, BMI, ASA physical status, tumor location, clinical T category, PCRT status, and preoperative obstruction. A 1:1 nearest-neighbor matching without replacement was performed using a predefined caliper. Matching quality was assessed using absolute standardized differences (ASD), with values of <0.1 considered indicative of adequate balance between groups [20]. Following matching, the McNemar test was used to compare categorical variables, while the Wilcoxon signed rank test was used for continuous variables. To analyze postoperative complications, generalized estimating equations with a logit link function were used for binary outcomes, such as anastomotic leakage, postoperative bleeding, ileus, SSI, and intra-abdominal hematoma within 30 days. For ordinal outcomes, such as the Clavien-Dindo classification of surgical complications, generalized estimating equations with a cumulative logit link were used to fit a proportional odds model. PSM analysis was conducted using SAS ver. 9.4 (SAS Institute Inc), while all other statistical analyses were performed using R ver. 4.3.3 (R Foundation for Statistical Computing).

RESULTS

Demographics

Before PSM, baseline clinical characteristics were generally comparable between the 2 groups, except for preoperative obstruction, which was more prevalent in the articulated instrument group. Following PSM, variables associated with the complexity of TME were well-balanced across both groups, as indicated by ASD values of <0.1 (Table 1). The mean age of patients was 62.6±9.9 years in the conventional group and 62.7±10.3 years in the articulated group before PSM. After PSM, the mean ages were 62.3±9.4 and 62.4±10.2 years, respectively, indicating a strong balance (ASD=0.018). The proportion of male patients was identical across groups following PSM, with 67.9% in both groups (ASD<0.001). Additionally, BMI and ASA physical status demonstrated adequate balance after matching, with mean BMI values of 23.7±3.3 kg/m² in the conventional group and 23.9±3.5 kg/m² in the articulated group. Tumor-related factors, including tumor location, clinical T category, PCRT usage, and obstruction rates, were also comparable between the groups after matching. This well-matched cohort allowed for an accurate and unbiased evaluation of the primary and secondary endpoints.

Intraoperative results

Intraoperative results were also analyzed (Table 2). The median operation time was 111.0 minutes (interquartile range [IQR], 95.8–125.2 minutes) in the articulated group and 99.5 minutes (IQR, 72.0–119.8 minutes) in the conventional group (P=0.009). Other intraoperative parameters, such as EBL and open conversion rates, showed no significant differences between the groups. In the conventional group, only 2 patients experienced an EBL exceeding 100 mL, whereas no such cases were observed in the articulated group after matching. Consequently, EBL was categorized into 2 groups for analysis: <10 and 10–100 mL. Stoma diversion was significantly more frequent in the articulated group compared to the conventional group (52.4% vs. 28.6%, P=0.002).

Pathologic outcomes

Pathologic outcomes including CRM and DRM are presented in Table 3. Before PSM, 4 cases were classified as "abutment" (CRM <1 mm), with 3 occurring in the conventional group and 1 in the articulated group. A significant proportion of cases in both groups lacked CRM assessment, necessitating a recategorization of CRM into 3 groups (<10 mm, ≥10 mm, and "not checked") to facilitate robust analysis. After PSM, the proportion of cases with CRM ≥10 mm was higher in the articulated group than in the conventional group (67.9% vs. 59.5%), but the difference was not statistically significant (P=0.613). In contrast, DRM length was significantly greater in the articulated group, with a median of 30.0 mm (IQR, 18.0–40.0 mm) compared to 24.0 mm (IQR, 12.0–34.2 mm) in the conventional group (P=0.008). Final pathologic T and N category distributions were not significantly different between the 2 groups (P=0.871 and P=0.557, respectively). The number of lymph nodes harvested also did not differ significantly between the groups (P=0.147), with median counts of 20 (IQR, 14–26) in the articulated group and 18 (IQR, 14–22) in the conventional group.

Postoperative complications

The median hospital stays and time to first flatus were comparable between the 2 groups, with no significant differences observed (Table 4). The conventional and articulated instrument groups recorded a median hospital stay of 6 days (IQR, 6–7 days; P=0.993). Similarly, the median time to the first flatus was 1 day (IQR, 1–2 days) for the conventional group and 1.5 days (IQR, 1–2 days) for the articulated group (P=0.742). Overall complication rates were slightly lower in the articulated group (22.6%) compared to the conventional group (27.4%), though this difference did not reach statistical significance (P=0.607). Readmission (1.2% vs. 3.6%, P=0.625) and reoperation (7.1% vs. 8.3%, P>0.999) rates were also comparable. When categorized according to the Clavien-Dindo classification, complications showed no significant intergroup differences. Most complications were classified as grade I or II, occurring in 12 patients (14.3%) in the articulated group and 15 patients (17.9%) in the conventional group. More severe complications (grades III–IV) were reported in 7 patients (8.3%) in the articulated group and 6 patients (7.1%) in the conventional group (P=0.923). Anastomotic-related complications, including leakage (7.1% vs. 8.3%, P>0.999) and anastomotic bleeding (2.4% vs. 1.2%; P>0.999), were also comparable between groups. Other postoperative complications, including AUR (4.8% in both groups; P>0.999), ileus (6.0% vs. 8.3%, P=0.773), and SSI (15.5% vs. 9.5%; P=0.383), also demonstrated no significant differences. Notably, intra-abdominal hematoma was observed in 4 cases (4.8%) within the conventional group, while no cases were reported in the articulated group (P=0.125).

DISCUSSION

This study compared articulated and conventional laparoscopic instruments in rectal cancer surgery using a propensity score–matched cohort. Both groups demonstrated comparable rates of CRM ≥10 mm, while the articulated group achieved a significantly longer DRM. Overall intraoperative and postoperative outcomes were similar between the 2 groups. Given the relative novelty of articulated devices, existing evidence remains limited—mostly from small case series or video reports—with few studies directly comparing them to conventional instruments in LAR [8, 11, 21]. This study therefore aimed to evaluate their potential benefits using a moderately sized, matched cohort for more robust comparison.

After matching, both groups achieved favorable pathological outcomes, with only 1 case of CRM abutment (<1 mm) in each group. The articulated group demonstrated a longer median DRM (30 mm vs. 24 mm, P=0.008) and a comparable proportion of CRM ≥10 mm (67.9% vs. 59.5%). These favorable findings align with prior studies on articulated instruments in TME. Kim et al. [11] reported that mean CRM and lymph node harvests in the articulated group were comparable to those achieved with robotic surgery, and Darwich et al. [21] similarly found no cases of CRM involvement in their initial evaluation. The significance of these findings becomes more apparent when compared to earlier randomized controlled trials. The ALaCaRT trial, for example, reported a 7% CRM positivity rate in the laparoscopic group [7], and the ACOSOG Z6051 trial recorded 87.9% negative CRM rate in 2015 [9]. In contrast, a more recent randomized controlled trial published in 2022 demonstrated a 98.2% negative CRM rate, closely aligning with the findings of the present study [22]. This progressive improvement in outcomes likely reflects not only changes in instrumentation, but also advancements in laparoscopic techniques, increased familiarity with TME, and the accumulation of surgeon experience over time.

On the other hand, the longer DRM achieved with articulated instruments might indicate their potential effectiveness in addressing challenges associated with distal rectal dissection, particularly in narrow pelvic spaces or cases involving bulky tumors. The enhanced maneuverability provided by the articulated features of these devices could facilitate more precise dissection, paralleling benefits observed in robotic surgery. Supporting this notion, studies by Feroci et al. [23] and Asoglu et al. [24] reported significantly longer DRMs in robotic TME compared to conventional laparoscopy. Achieving a sufficiently long DRM enables a safer and more secure anastomosis, highlighting the practical utility of articulated instruments in rectal surgery. Despite these findings, the oncologic significance of an extended DRM remains debatable. While some studies suggest that oncological outcomes are unaffected as long as the margin remains uninvolved, others propose varying cutoffs for oncological safe DRM [25, 26]. Additional studies are required to determine whether extended DRM offers any survival or recurrence benefits.

Other intraoperative outcomes, including EBL and open conversion rates, did not differ significantly between the groups. This contrasts with findings from previous studies, which have reported reduced EBL with articulated instruments, suggesting their role in facilitating meticulous dissection [10, 11]. Furthermore, our study revealed significantly longer operation times in the articulated group (111.0 minutes [IQR, 95.8–125.2 minutes] vs. 99.5 minutes [IQR, 72.0–119.8 minutes], P=0.009), although those operation time is still comparable to other previous reports on laparoscopic LAR [8, 11, 27]. Despite well-matched preoperative characteristics between groups, the prolonged operative time observed might be attributed to the need of learning curve when adopting novel articulated devices. Supporting this interpretation, Shin et al. [10] reported that surgeon proficiency with articulated devices improved after the initial 10 cases, suggesting that this threshold might represent the learning curve for these instruments. However, their study found shorter operative times with articulated instruments, likely influenced by the inclusion of a broader range of colorectal procedures, from small bowel resection and anastomosis to abdominopelvic resection, making direct comparison with our study, focused on a confined pelvic cavity, challenging. Additionally, the higher rate of stoma diversion in the articulated group (52.4% vs. 28.6%, P=0.002) might have contributed to the extended operative times observed in this study. Despite the increased diversion rate, this did not result in higher complications rates or prolonged hospital stays.

Postoperative outcomes, including complication rates, hospital stay, and time to first flatus, were comparable between the groups, suggesting that articulated devices offer similar level of safety and feasibility as conventional devices. AUR was specifically evaluated as genitourinary function is associated with autonomic nerve preservation in pelvic malignancy surgeries [6]. While prior research has suggested that robotic TME reduced postoperative urinary retention [28], our study found no statistically significant differences in AUR or other postoperative complications between the articulated and conventional instrument groups.

Limitations and future directions

This study has several limitations. First, it was a single-center, retrospective study without randomization or blinding, which may limit the generalizability of the findings and introduces inherent selection bias, despite the use of PSM. In addition, surgeon-related factors were not standardized, as the use of articulated devices was based on individual preference. This may have led to a more cautious approach in some cases, including a lower threshold for diverting stoma formation, and could have contributed to longer operative times, even though baseline characteristics were matched. Given that articulated instruments were introduced relatively recently, the potential impact of the learning curve cannot be excluded. Future studies should assess outcomes after surgeons have undergone sufficient adaptation periods. Moreover, this analysis focused exclusively on short-term outcomes, leaving key long-term considerations unexamined, particularly the incidence of LAR syndrome. Previous research suggests that robotic LAR might reduce the incidence of LAR syndrome [29, 30], and further research is warranted to evaluate whether articulated laparoscopic instruments offer similar advantages.

Finally, the economic implications of adopting articulated instruments deserve careful consideration. Roughly each articulated device costs approximately US $600, representing a substantial increase over conventional laparoscopic instruments [31]. Although this study did not include a formal cost-effectiveness analysis, the added financial burden may limit their broader adoption. Future studies should investigate whether the potential clinical benefits of these devices justify their additional cost in routine surgical practice.

Conclusions

Articulated laparoscopic instruments have demonstrated comparable pathological outcomes and complication rates to conventional instruments in rectal cancer surgery. While they achieved a longer DRM, their oncological significance remains uncertain, and they showed longer operative time. As laparoscopic techniques continue to evolve, articulated devices may offer potential benefits in precision and efficiency during TME. However, further research with larger cohorts and extended follow-up periods is necessary to determine their true value and facilitate their integration into standard laparoscopic practice.

ARTICLE INFORMATION

Conflict of interest

In Ja Park is the editor-in-chief and Young Il Kim is the editorial board member of this journal, but were not involved in the peer reviewer selection, evaluation, or decision process of this article. No other potential conflict of interest relevant to this article was reported.

Funding

None.

Acknowledgments

The authors thank the Department of Clinical Epidemiology and Biostatistics, Asan Medical Center, University of Ulsan College of Medicine, for their invaluable support in the statistical analysis of this study.

Author contributions

Conceptualization: YSY, HL; Investigation: HL; Methodology: YSY, MHK, YIK; Project administration: YSY, CWK, JLL; Resources: SBL, IJP, YSY, CWK, JLL, MHK, YIK; Supervision: YSY, IJP; Validation: YSY, MHK, YIK; Visualization: HL; Writing–original draft: YSY, HL; Writing–review & editing: SBL, IJP, YSY, CWK, JLL, MHK, YIK. All authors read and approved the final manuscript.

SUPPLEMENTARY MATERIALS

Supplementary Table 1.

Completed STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) checklist for cohort studies

ac-2025-00227-0032-Supplementary-Table-1.pdf

Supplementary materials are available from https://doi.org/10.3393/ac.2025.00227.0032.

Fig. 1.

Flowchart of patient selection and propensity score matching.

Fig. 2.

Actual use of articulated devices in laparoscopic mesorectal excision. (A) An articulated grasper providing traction on the mesorectum beyond the rectal tumor on the anterior side. (B) An articulated endobovie used for dissection of the mesorectum on the posterior side.

Fig. 3.

Trocar placements for laparoscopic low anterior resection in entire cohort.

Table 1.

Baseline characteristics of patients stratified by instrument type before and after PSM

Characteristic	Before PSM			After PSM
Characteristic	Conventional instrument (n=346)	Articulated instrument (n=86)	ASD	Conventional instrument (n=84)	Articulated instrument (n=84)	ASD
Age (yr)	62.6±9.9	62.7±10.3	0.011	62.3±9.4	62.4±10.2	0.018
Male sex	245 (70.8)	57 (66.3)	0.098	57 (67.9)	57 (67.9)	<0.001
Body mass index (kg/m²)	23.9±3.7	23.9±3.5	0.021	23.7±3.3	23.9±3.5	0.070
ASA physical status			0.059
I–II	312 (90.2)	79 (91.9)		77 (91.7)	78 (92.9)	0.050
III–V	34 (9.8)	7 (8.1)		7 (8.3)	6 (7.1)
Tumor location^a			0.015			0.077
Above	243 (70.2)	61 (70.9)		56 (66.7)	59 (70.2)
Below	103 (29.8)	25 (29.1)		28 (33.3)	25 (29.8)
Clinical T category			0.079			0.078
cT1–cT2	109 (31.5)	24 (27.9)		27 (32.1)	24 (28.6)
cT3–cT4	237 (68.5)	62 (72.1)		57 (67.9)	60 (71.4)
Preoperative chemoradiotherapy	44 (12.7)	9 (10.5)	0.070	9 (10.7)	9 (10.7)	<0.001
Preoperative obstruction			0.200			0.032
Complete	47 (13.6)	14 (16.3)		15 (17.9)	14 (16.7)
Endoscopic	8 (2.3)	5 (5.8)		3 (3.6)	3 (3.6)
No	291 (84.1)	67 (77.9)		66 (78.6)	67 (79.8)

Values are presented as mean±standard deviation or number (%). An ASD below 0.10 indicates a well-balanced comparison.

PSM, propensity score matching; ASD, absolute standardized difference; ASA, American Society of Anesthesiologists.

^aRelative to peritoneal reflection.

Table 2.

Intraoperative and postoperative pathological data in the propensity score–matched sample

Variable	Conventional instrument (n=84)	Articulated instrument (n=84)	P-value
Open conversion	1 (1.2)	0 (0)	>0.999
Estimated blood loss (mL)			0.871
<10	52 (61.9)	52 (61.9)
10–100	30 (35.7)	32 (38.1)
>100	2 (2.4)	0 (0)
Operation time (min)	99.5 (72.0–119.8)	111.0 (95.8–125.2)	0.009
Stoma diversion	24 (28.6)	44 (52.4)	0.002

Values are presented as a number (%) or median (interquartile range).

Table 3.

Pathologic outcomes in the propensity score–matched sample

Outcome	Conventional instrument (n=84)	Articulated instrument (n=84)	P-value
Pathologic T category			0.871
T1–T2	30 (35.7)	28 (33.3)
T3–T4	54 (64.3)	56 (66.7)
Pathologic N category			0.557
N0	48 (57.1)	54 (64.3)
N1	25 (29.8)	19 (22.6)
N2	11 (13.1)	11 (13.1)
No. of lymph nodes harvested	18 (14–22)	20 (14–26)	0.147
Circumferential resection margin			0.613
<10 mm	23 (27.4)	18 (21.4)
≥10 mm	50 (59.5)	57 (67.9)
Not checked	11 (13.1)	9 (10.7)
Distal resection margin (mm)	24.0 (12.0–34.2)	30.0 (18.0–40.0)	0.008

Values are presented as a number (%) or median (interquartile range).

Table 4.

Comparisons of postoperative outcomes and complications

Outcome	Conventional instrument (n=84)	Articulated instrument (n=84)	P-value
Length of hospital stay (day)	6 (6–7)	6 (6–7)	0.993
Time to first flatus (day)	1 (1–2)	1.5 (1–2)	0.742
Overall complication	23 (27.4)	19 (22.6)	0.607
Readmission	3 (3.6)	1 (1.2)	0.625
Reoperation	7 (8.3)	6 (7.1)	>0.999
Clavien-Dindo classification			0.923
I–II	15 (17.9)	12 (14.3)
III–IV	6 (7.1)	7 (8.3)
Anastomosis-related complication
Leakage	6 (7.1)	7 (8.3)	>0.999
Anastomotic bleeding	2 (2.4)	1 (1.2)	>0.999
Other complication
Acute urinary retention	4 (4.8)	4 (4.8)	>0.999
Ileus	7 (8.3)	5 (6.0)	0.773
Surgical site infection	8 (9.5)	13 (15.5)	0.383
Intra-abdominal hematoma	4 (4.8)	0 (0)	0.125

Values are presented as median (interquartile range) or number (%).

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Comparative perioperative outcomes of articulated versus conventional straight devices in laparoscopic low anterior resection: a propensity score–matched analysis

Ann Coloproctol. 2025;41(5):434-442. Published online October 16, 2025

DOI: https://doi.org/10.3393/ac.2025.00227.0032

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Comparative perioperative outcomes of articulated versus conventional straight devices in laparoscopic low anterior resection: a propensity score–matched analysis

Fig. 1. Flowchart of patient selection and propensity score matching.

Fig. 2. Actual use of articulated devices in laparoscopic mesorectal excision. (A) An articulated grasper providing traction on the mesorectum beyond the rectal tumor on the anterior side. (B) An articulated endobovie used for dissection of the mesorectum on the posterior side.

Fig. 3. Trocar placements for laparoscopic low anterior resection in entire cohort.

Fig. 1.

Fig. 2.

Fig. 3.

Comparative perioperative outcomes of articulated versus conventional straight devices in laparoscopic low anterior resection: a propensity score–matched analysis

Characteristic	Before PSM			After PSM
Characteristic	Conventional instrument (n=346)	Articulated instrument (n=86)	ASD	Conventional instrument (n=84)	Articulated instrument (n=84)	ASD
Age (yr)	62.6±9.9	62.7±10.3	0.011	62.3±9.4	62.4±10.2	0.018
Male sex	245 (70.8)	57 (66.3)	0.098	57 (67.9)	57 (67.9)	<0.001
Body mass index (kg/m²)	23.9±3.7	23.9±3.5	0.021	23.7±3.3	23.9±3.5	0.070
ASA physical status			0.059
I–II	312 (90.2)	79 (91.9)		77 (91.7)	78 (92.9)	0.050
III–V	34 (9.8)	7 (8.1)		7 (8.3)	6 (7.1)
Tumor location^a			0.015			0.077
Above	243 (70.2)	61 (70.9)		56 (66.7)	59 (70.2)
Below	103 (29.8)	25 (29.1)		28 (33.3)	25 (29.8)
Clinical T category			0.079			0.078
cT1–cT2	109 (31.5)	24 (27.9)		27 (32.1)	24 (28.6)
cT3–cT4	237 (68.5)	62 (72.1)		57 (67.9)	60 (71.4)
Preoperative chemoradiotherapy	44 (12.7)	9 (10.5)	0.070	9 (10.7)	9 (10.7)	<0.001
Preoperative obstruction			0.200			0.032
Complete	47 (13.6)	14 (16.3)		15 (17.9)	14 (16.7)
Endoscopic	8 (2.3)	5 (5.8)		3 (3.6)	3 (3.6)
No	291 (84.1)	67 (77.9)		66 (78.6)	67 (79.8)

Variable	Conventional instrument (n=84)	Articulated instrument (n=84)	P-value
Open conversion	1 (1.2)	0 (0)	>0.999
Estimated blood loss (mL)			0.871
<10	52 (61.9)	52 (61.9)
10–100	30 (35.7)	32 (38.1)
>100	2 (2.4)	0 (0)
Operation time (min)	99.5 (72.0–119.8)	111.0 (95.8–125.2)	0.009
Stoma diversion	24 (28.6)	44 (52.4)	0.002

Outcome	Conventional instrument (n=84)	Articulated instrument (n=84)	P-value
Pathologic T category			0.871
T1–T2	30 (35.7)	28 (33.3)
T3–T4	54 (64.3)	56 (66.7)
Pathologic N category			0.557
N0	48 (57.1)	54 (64.3)
N1	25 (29.8)	19 (22.6)
N2	11 (13.1)	11 (13.1)
No. of lymph nodes harvested	18 (14–22)	20 (14–26)	0.147
Circumferential resection margin			0.613
<10 mm	23 (27.4)	18 (21.4)
≥10 mm	50 (59.5)	57 (67.9)
Not checked	11 (13.1)	9 (10.7)
Distal resection margin (mm)	24.0 (12.0–34.2)	30.0 (18.0–40.0)	0.008

Outcome	Conventional instrument (n=84)	Articulated instrument (n=84)	P-value
Length of hospital stay (day)	6 (6–7)	6 (6–7)	0.993
Time to first flatus (day)	1 (1–2)	1.5 (1–2)	0.742
Overall complication	23 (27.4)	19 (22.6)	0.607
Readmission	3 (3.6)	1 (1.2)	0.625
Reoperation	7 (8.3)	6 (7.1)	>0.999
Clavien-Dindo classification			0.923
I–II	15 (17.9)	12 (14.3)
III–IV	6 (7.1)	7 (8.3)
Anastomosis-related complication
Leakage	6 (7.1)	7 (8.3)	>0.999
Anastomotic bleeding	2 (2.4)	1 (1.2)	>0.999
Other complication
Acute urinary retention	4 (4.8)	4 (4.8)	>0.999
Ileus	7 (8.3)	5 (6.0)	0.773
Surgical site infection	8 (9.5)	13 (15.5)	0.383
Intra-abdominal hematoma	4 (4.8)	0 (0)	0.125

Table 1. Baseline characteristics of patients stratified by instrument type before and after PSM

Values are presented as mean±standard deviation or number (%). An ASD below 0.10 indicates a well-balanced comparison.

PSM, propensity score matching; ASD, absolute standardized difference; ASA, American Society of Anesthesiologists.

Relative to peritoneal reflection.

Table 2. Intraoperative and postoperative pathological data in the propensity score–matched sample

Values are presented as a number (%) or median (interquartile range).

Table 3. Pathologic outcomes in the propensity score–matched sample

Values are presented as a number (%) or median (interquartile range).

Table 4. Comparisons of postoperative outcomes and complications

Values are presented as median (interquartile range) or number (%).