Comparison of the Left-Lateral Horizontal and Supine Positions for Colonoscopy Intervention: A Randomized Controlled Study

Objective: One of the most common technical difficulties during colonoscopy is passing through the fold of the sigmoid colon. Colonoscopy is commonly performed by endoscopists with the patient in the left lateral position. When the procedure is initiated in the left lateral position, insufflation of the bowel may result in a sharper angulation of the sigmoid colon, making advancement of the colonoscope more difficult. This study aimed to compare colonoscopic procedures initiated in the left lateral position and the supine position.

Materials and Methods: Colonoscopy was performed on 198 participants who had an indication for colonoscopy at the General Surgery clinic and met the study inclusion criteria. All procedures were conducted by the same endoscopist (Dr. Semra Tutcu Şahin) in the Endoscopy Unit during working hours. Participants were randomly assigned to two groups:

Group 1: Participants whose starting position for colonoscopy was supine (n=97) Group 2: Participants whose starting position for colonoscopy was left lateral (n=101)

During colonoscopy, participants' demographic data, vital signs, and the time required for the endoscopist to reach the cecum were recorded. At the end of the procedure, participants completed a pain scale, and the endoscopist completed an observation scale. The data were entered into the SPSS program and analyzed.

Study Overview

• Status: Completed
• Conditions: Colorectal Neoplasms; Colorectal Disorders; Colo-rectal Cancer; Colorectal Polyp
• Intervention / Treatment: Procedure: Colonoscopy after bowel cleansing; Device: Colonoscopy after bowel cleansing

Detailed Description

Objective: One of the most common technical difficulties during colonoscopy is passing through the fold of the sigmoid colon. Colonoscopy is commonly performed by endoscopists with the patient in the left lateral position. When the procedure is initiated in the left lateral position, insufflation of the bowel may result in a sharper angulation of the sigmoid colon, making advancement of the colonoscope more difficult. This study aimed to compare colonoscopic procedures initiated in the left lateral position and the supine position.

Materials and Methods: Colonoscopy was performed on 198 participants who had an indication for colonoscopy at the General Surgery clinic and met the study inclusion criteria. All procedures were conducted by the same endoscopist (Dr. Semra Tutcu Şahin) in the Endoscopy Unit during working hours. Participants were randomly assigned to two groups:

Group 1: Participants whose starting position for colonoscopy was supine (n=97) Group 2: Participants whose starting position for colonoscopy was left lateral (n=101)

During colonoscopy, participants' demographic data, vital signs, and the time required for the endoscopist to reach the cecum were recorded. At the end of the procedure, participants completed a pain scale, and the endoscopist completed an observation scale. The data were entered into the SPSS program and analyzed.

• Study Type: Interventional
• Enrollment (Actual): 198
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Manisa, Turkey (Türkiye)
    • Manisa Celal Bayar University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Female and male patients over 18 years of age who have been medically indicated for colonoscopy and have signed the voluntary consent form.

Exclusion Criteria:

• Patients under 18 years of age
• Patients who do not give informed consent
• Pregnant women
• Patients requesting sedation
• Patients with an indication for emergency colonoscopy
• Patients with a history of colon resection
• Major psychiatric disorders

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: Supine position (SP); The first group consisted of patients assigned to the supine position (SP) as the initial position for colonoscopy	Procedure: Colonoscopy after bowel cleansing; Colonoscopy after bowel cleansing; Device: Colonoscopy after bowel cleansing; COLONOSCOPY WITH LEFT LATERAL AND SUPINE POSITION
Other: Lateral Left Horizontal Position (LLP); The second group consisted of patients assigned to the left lateral horizontal position (LLP) as the initial position for colonoscopy	Procedure: Colonoscopy after bowel cleansing; Colonoscopy after bowel cleansing; Device: Colonoscopy after bowel cleansing; COLONOSCOPY WITH LEFT LATERAL AND SUPINE POSITION

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cecal intubation time	Time (in seconds) from insertion of the colonoscope at the anal verge to successful cecal intubation, defined by visualization of the appendiceal orifice and ileocecal valve, recorded by the endoscopist.	During the colonoscopy procedure

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pain score during colonoscopy	Pain intensity assessed immediately after the procedure using a 10-point Visual Analog Scale (VASP), where 0 indicates no pain and 10 indicates worst imaginable pain.	Immediately after colonoscopy
Endoscopist-rated procedure difficulty	Procedure difficulty assessed immediately after colonoscopy using a 4-point Likert scale (1 = very easy, 2 = easy, 3 = difficult, 4 = very difficult), as rated by the endoscopist.	Immediately after colonoscopy
Changes in vital signs during colonoscopy	Heart rate (beats per minute) measured at baseline and at 5-minute intervals during the procedure. The maximum change from baseline will be recorded.	During the colonoscopy procedure

Collaborators and Investigators

• Sponsor: Celal Bayar University

Publications and helpful links

General Publications

• McKechnie T, Heimann L, Kazi T, Jessani G, Lee Y, Sne N, et al. Starting position during colonoscopy: a systematic review and meta-analysis of randomized controlled trials. Tech Coloproctol [Internet]. 2024;28.
• Watanabe J. Comparison of left versus right lateral starting position on colonoscopy: A systematic review and meta-analysis of randomized controlled trials. Ann Gastroenterol. 2021;34:699-704.
• Watanabe J, Park D, Kakehi E, Inoue K, Ishikawa S, Kataoka Y. Efficacy and safety of the starting position during colonoscopy: a systematic review and meta-analysis. Endosc Int Open. 2020;08:848-60.
• 1. Li N, Lu B, Luo C, Cai J, Lu M, Zhang Y, et al. Incidence, mortality, survival, risk factor and screening of colorectal cancer: A comparison among China, Europe, and northern America. Cancer Lett. 2021;522:255-68.

Study record dates

Study Major Dates

• Study Start (Actual): February 1, 2021
• Primary Completion (Actual): October 1, 2023
• Study Completion (Actual): August 15, 2024

Study Registration Dates

• First Submitted: December 6, 2025
• First Submitted That Met QC Criteria: April 4, 2026
• First Posted (Actual): April 8, 2026

Study Record Updates

• Last Update Posted (Actual): April 8, 2026
• Last Update Submitted That Met QC Criteria: April 4, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: colorectal cancer; colonoscopy; endoscopy; colon polyps
• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Pathological Conditions, Anatomical; Intestinal Diseases; Gastrointestinal Neoplasms; Digestive System Neoplasms; Digestive System Diseases; Gastrointestinal Diseases; Intestinal Neoplasms; Rectal Diseases; Colonic Diseases; Polyps; Intestinal Polyps; Pathological Conditions, Signs and Symptoms; Colorectal Neoplasms; Colonic Neoplasms; Colonic Polyps
• Other Study ID Numbers: CelalBayarU

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Anonymized study results
• IPD Sharing Time Frame: Beginning 1 month after publication with no end date
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No