UMIN-ICDS Clinical Trial

Public title

A comparative study of posterior supporting tissue injury between uniportal and biportal full-endoscopic lumbar decompression

Acronym

FEL/AFESS posterior tissue injury study

Scientific Title

Comparison of posterior supporting tissue injury between uniportal and biportal full-endoscopic lumbar decompression: a prospective observational study

Scientific Title:Acronym

FEL/AFESS posterior tissue injury study

Region

Japan

Condition

Lumbar spinal stenosis

Classification by specialty

Orthopedics

Classification by malignancy

Others

Genomic information

NO

Narrative objectives1

The objective of this study is to compare changes in the cross-sectional area of the multifidus muscle from preoperative MRI to approximately 6 months after surgery between uniportal and biportal full-endoscopic lumbar decompression for lumbar spinal stenosis, and to clarify the degree of posterior supporting tissue injury associated with each surgical technique.

Basic objectives2

Others

Basic objectives -Others

Radiological comparison of surgical invasiveness and posterior supporting tissue injury between surgical techniques

Trial characteristics_1

Exploratory

Trial characteristics_2

Explanatory

Developmental phase

Not applicable

Primary outcomes

Percent change in the cross-sectional area of the multifidus muscle from preoperative MRI to MRI approximately 6 months after surgery

Key secondary outcomes

Key secondary outcomes include absolute changes in multifidus cross-sectional area; changes in multifidus cross-sectional area on the approach and contralateral sides; dural sac cross-sectional area and its absolute and percent changes; early postoperative MRI findings; patient-reported outcomes before surgery and 3, 6, and 12 months after surgery; operative time; length of hospital stay; complications; reoperation; and readmission.

Study type

Observational

Basic design

Randomization

Randomization unit

Blinding

Control

Stratification

Dynamic allocation

Institution consideration

Blocking

Concealment

No. of arms

Purpose of intervention

Type of intervention

Interventions/Control_1

Interventions/Control_2

Interventions/Control_3

Interventions/Control_4

Interventions/Control_5

Interventions/Control_6

Interventions/Control_7

Interventions/Control_8

Interventions/Control_9

Interventions/Control_10

Age-lower limit

20

years-old

<=

Age-upper limit

Not applicable

Gender

Male and Female

Key inclusion criteria

1. Patients undergoing one- or two-level full-endoscopic lumbar decompression for lumbar spinal stenosis, mainly due to degenerative disease, at our hospital.
2. Patients undergoing either uniportal or biportal full-endoscopic lumbar decompression.
3. Patients aged 20 years or older at the time of surgery.
4. Patients who undergo preoperative MRI and MRI approximately 6 months after surgery and in whom the cross-sectional area of the multifidus muscle can be evaluated.
5. Patients who undergo postoperative CT at 1-2 days, postoperative MRI at 3-4 days, MRI approximately 6 months after surgery, and routine clinical symptom assessment according to the clinical pathway of our hospital.

Key exclusion criteria

1. Patients whose main pathology is not lumbar spinal stenosis, such as tumor, infection, trauma, or inflammatory disease.
2. Patients undergoing concomitant fusion surgery.
3. Patients undergoing decompression at three or more levels.
4. Patients with a history of previous surgery at the target level.
5. Patients who cannot undergo preoperative MRI or MRI approximately 6 months after surgery due to contraindications to MRI or other reasons.
6. Patients in whom image assessment is technically difficult due to severe artifacts, inconsistent imaging range, or other reasons.
7. Patients who refuse the use of their information through the opt-out process.
8. Patients judged by the principal investigator to be inappropriate for this study.

Target sample size

140

Name of lead principal investigator

1st name	Shota
Middle name
Last name	Takenaka

Organization

Department of Orthopaedic Surgery, Japan Community Healthcare Organization Osaka Hospital

Division name

Department of Orthopaedic Surgery

Zip code

553-0003

Address

4-2-78 Fukushima, Fukushima-ku, Osaka City, Osaka, Japan

TEL

06-6441-5451

Email

show710216@gmail.com

Name of contact person

1st name	Sadaaki
Middle name
Last name	Kanayama

Organization

Japan Community Healthcare Organization Osaka Hospital

Division name

Department of Orthopaedic Surgery

Zip code

553-0003

Address

4-2-78 Fukushima, Fukushima-ku, Osaka City, Osaka, Japan

TEL

06-6441-5451

Homepage URL

Email

drsada@jewel.ocn.ne.jp

Institute

Japan Community Healthcare Organization Osaka Hospital

Institute

Department

Personal name

Shota Takenaka

Organization

Self funding

Organization

Division

Category of Funding Organization

Self funding

Nationality of Funding Organization

Japan

Co-sponsor

Name of secondary funder(s)

Organization

Japan Community Healthcare Organization Osaka Hospital review board

Address

4-2-78 Fukushima, Fukushima-ku, Osaka City, Osaka, Japan

Tel

06-6441-5451

Email

horimoto-takiko@osaka.jcho.go.jp

Secondary IDs

NO

Study ID_1

Org. issuing International ID_1

Study ID_2

Org. issuing International ID_2

IND to MHLW

Institutions

独立行政法人地域医療機能推進機構大阪病院 整形外科

Date of disclosure of the study information

2026

Year

05

Month

21

Day

URL releasing protocol

Publication of results

Unpublished

URL related to results and publications

Number of participants that the trial has enrolled

Results

Results date posted

Results Delayed

Results Delay Reason

Date of the first journal publication of results

Baseline Characteristics

Participant flow

Adverse events

Outcome measures

Plan to share IPD

No plan to share individual participant data

IPD sharing Plan description

Recruitment status

Open public recruiting

Date of protocol fixation

2026

Year

05

Month

10

Day

Date of IRB

2026

Year

05

Month

20

Day

Anticipated trial start date

2026

Year

05

Month

20

Day

Last follow-up date

2029

Year

03

Month

31

Day

Date of closure to data entry

Date trial data considered complete

Date analysis concluded

Other related information

This is a single-center prospective observational study without intervention, including patients aged 20 years or older who undergo one- or two-level uniportal or biportal full-endoscopic lumbar decompression for lumbar spinal stenosis as part of routine clinical practice. The surgical technique is selected by the attending surgeon, and no allocation of surgical technique is performed for research purposes. Observed variables include patient characteristics, diagnosis, surgical technique, operated level, number of decompressed levels, operative time, complications, preoperative MRI, postoperative CT at 1-2 days, postoperative MRI at 3-4 days, MRI approximately 6 months after surgery, plain radiographs, and preoperative and postoperative symptom assessments. The primary outcome is the percent change in the cross-sectional area of the multifidus muscle from preoperative MRI to MRI approximately 6 months after surgery, which will be compared between the uniportal and biportal groups. Secondary observations include dural sac cross-sectional area, early postoperative MRI findings, symptom assessments, length of hospital stay, reoperation, and readmission. No additional examinations, imaging studies, blood tests, questionnaires, or treatments are performed for research purposes.

Registered date

2026

Year

05

Month

21

Day

Last modified on

2026

Year

05

Month

21

Day

Link to view the page

Value
https://center6.umin.ac.jp/cgi-open-bin/icdr_e/ctr_view.cgi?recptno=R000070378