---
title: The Effect of Leg Position on the Sciatic Nerve on Sonogram
nct_id: NCT03678961
overall_status: COMPLETED
sponsor: Asan Medical Center
study_type: OBSERVATIONAL
primary_condition: Sciatic Nerve Block
countries: South Korea
canonical_url: "https://parkinsonspathways.com/agent/trials/NCT03678961.md"
clinicaltrials_gov: "https://clinicaltrials.gov/study/NCT03678961"
ct_last_update_post_date: 2018-12-20
last_seen_at: "2026-05-12T06:17:12.985Z"
source: ClinicalTrials.gov (mirrored, no enrichment)
---
# The Effect of Leg Position on the Sciatic Nerve on Sonogram

**Official Title:** Influence of Lower Extremity Positioning During Anterior-approach Ultrasound-guided Sciatic Nerve Block: Depth and Visibility

**NCT ID:** [NCT03678961](https://clinicaltrials.gov/study/NCT03678961)

## Key Facts

- **Status:** COMPLETED
- **Study Type:** OBSERVATIONAL
- **Target Enrollment:** 45
- **Lead Sponsor:** Asan Medical Center
- **Conditions:** Sciatic Nerve Block
- **Start Date:** 2018-08-30
- **Completion Date:** 2018-10-11
- **CT.gov Last Update:** 2018-12-20

## Brief Summary

Little is known about which posture of lower extremity makes it easier to access to the sciatic nerve. In this study, the investigators aimed to identify the most appropriate positioning of the lower extremity during anterior-approach ultrasound-guided sciatic nerve block.

## Eligibility

- **Minimum age:** 18 Years
- **Maximum age:** 80 Years
- **Sex:** ALL
- **Healthy Volunteers:** No

```
Inclusion Criteria:

* ASA PS 1-3
* patients undergoing knee surgery requiring peripheral nerve block

Exclusion Criteria:

* patients who refuse to participate in the study
* BMI \> 40 kg/m2
* patients who have congenital abnormality on leg
* patients who have surgery or trauma on hip/knee
* patients who cannot move freely due to the contracture
* patients who are judged ineligible by the medical staff to participate in the study for other reasons
```

## Arms

- **Group N** — Neutral position
- **Group E** — External rotation of leg by 45 degrees
- **Group EF45** — External rotation of leg by 45 degrees, hip flexion by 45 degrees, and knee flexion by 45 degrees
- **Group EF15** — External rotation of leg by 45 degrees, hip flexion by 15 degrees, and knee flexion by 15 degrees

## Interventions

- **external rotation of leg** (BEHAVIORAL) — external rotation of leg by 45 degrees
- **hip flexion and knee flexion** (BEHAVIORAL) — hip flexion by 15/45 degrees and knee flexion by 15/45 degrees

## Primary Outcomes

- **Visibility of sciatic nerve** _(time frame: during 10 minutes of anesthesia induction)_ — Visibility of sciatic nerve at each position assessed using a scoring system (0, no nerve identified; 1, nerve identified with a high probability; 2, nerve identified, but most of it not visible; 3, nerve identified, more than 50% of its borders can be precisely distinguished from surrounding structures; 4, nerve completely visible, but fascicles poorly defined; 5, nerve completely visible and multiple fascicles identifiable.)

## Secondary Outcomes

- **Depth of sciatic nerve** _(time frame: during 10 minutes of anesthesia induction)_

## Locations (1)

- Asan Medical Center, Seoul, South Korea

## Recent Field Changes (last 30 days)

- `eligibility.minAge` — added _(2026-05-12)_
- `eligibility.maxAge` — added _(2026-05-12)_
- `eligibility.sex` — added _(2026-05-12)_
- `status.lastUpdatePostDate` — added _(2026-05-12)_
- `design.enrollmentCount` — added _(2026-05-12)_
- `eligibility.criteria` — added _(2026-05-12)_
- `status.overallStatus` — added _(2026-05-12)_
- `status.primaryCompletionDate` — added _(2026-05-12)_
- `status.completionDate` — added _(2026-05-12)_
- `outcomes.primary` — added _(2026-05-12)_
- `outcomes.secondary` — added _(2026-05-12)_
- `armsInterventions.arms` — added _(2026-05-12)_
- `armsInterventions.interventions` — added _(2026-05-12)_
- `sponsor.lead` — added _(2026-05-12)_
- `results.hasResults` — added _(2026-05-12)_
- `locations.asan medical center|seoul||south korea` — added _(2026-05-12)_

---

*Canonical: https://parkinsonspathways.com/agent/trials/NCT03678961.md*  
*Source data (authoritative): https://clinicaltrials.gov/study/NCT03678961*  
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