Immediate and 1-week Efficacy of a Single Session of Sciatic Nerve Electrical Stimulation in the Management of Low-back Related Leg Pain
1 other identifier
interventional
88
1 country
1
Brief Summary
This clinical study focuses on people who experience long-term low-back related leg pain (commonly called sciatica). This type of pain is often associated with nerve irritation or compression in the lower spine and can cause symptoms like shooting or burning pain, tingling, numbness, or weakness in the leg. Many patients continue to suffer from this problem for months or years, and available treatments (including painkillers, anti-inflammatory drugs, or even surgery) do not always provide lasting relief. Because of this, there is a strong need to explore safe, non-drug, non-surgical therapies. The purpose of this study is to test the immediate and short-term efficacy and safety of a single session of a treatment called Percutaneous Electrical Nerve Stimulation (PENS) when applied near the sciatic nerve, the large nerve that runs from the lower back through the buttock and down the leg. PENS uses very thin sterile needles inserted under ultrasound guidance next to the nerve. A gentle electrical current is then applied for about 30 minutes to stimulate the nerve in a controlled way. This may help calm down nerve sensitivity, reduce inflammation, and decrease pain. The investigators will compare PENS with three other options: Transcutaneous Electrical Nerve Stimulation (TENS): A commonly used therapy where mild electrical stimulation is applied through adhesive patches placed on the skin; Dry needling without electrical current: Thin needles are inserted under ultrasound guidance but no current is applied; and placebo treatment: A simulated version of the therapy with no active current, designed to look and feel similar so that participants do not know which treatment they are receiving. The study is designed as a randomized, controlled, double-blind trial, which means that participants are assigned to one of the four groups by chance (like flipping a coin), and neither the patients nor the therapists who collect the measurements will know which treatment has been given. This design ensures fairness and reliability of the results. The investigators will measure: Back and leg pain levels, using a simple 0-10 scale; Disability, meaning how much the pain limits daily activities, measured with a well-known questionnaire; Quality of life, both physical and mental health aspects; Nerve-related pain features, like burning or electric-like sensations; Flexibility and movement, through the Straight Leg Raise test; Sensitivity to pressure and nerve stiffness, using ultrasound elastography, which is a safe imaging technique; and patients' global impression of improvement and any side effects. Assessments will take place before and immediately after the treatment session and after 1 week, allowing the investigators to see both the immediate and short-term effects. Safety considerations: Previous research shows that PENS and similar techniques are generally very safe. The most common side effects are mild and short-lasting, including temporary soreness, heaviness in the leg, or a small bruise. Serious complications are extremely rare. To minimize risks, all procedures will be carried out by experienced physiotherapists, using real-time ultrasound to guide needle placement and ensure accuracy. Only sterile, single-use needles are employed. By comparing PENS, TENS, dry needling, and placebo, this study seeks to determine whether a single session of PENS provides superior benefits in reducing pain, improving function, and enhancing quality of life for patients with sciatica-type low back pain. If successful, this treatment could become a valuable alternative to drugs or surgery, offering patients a safe and effective therapy to better manage their condition and regain daily function.
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at P50-P75 for not_applicable
Started May 2026
1 active site
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
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Study Timeline
Key milestones and dates
First Submitted
Initial submission to the registry
November 25, 2025
CompletedFirst Posted
Study publicly available on registry
January 29, 2026
CompletedStudy Start
First participant enrolled
May 13, 2026
CompletedPrimary Completion
Last participant's last visit for primary outcome
December 1, 2026
ExpectedStudy Completion
Last participant's last visit for all outcomes
November 1, 2027
May 14, 2026
November 1, 2025
7 months
November 25, 2025
May 13, 2026
Conditions
Outcome Measures
Primary Outcomes (1)
Pain intensity
Pain intensity will be assessed using the NPRS, a single 11-point numerical rating scale widely validated across different patient populations, where 0 represents no pain and 10 represents the worst possible pain. Data obtained through the NPRS are easy to document, intuitively interpretable and meet regulatory requirements for pain assessment and documentation. The NPRS has been shown to be reliable in assessing LBP intensity, also predicting the degree of disability in these patients. A change of 2 points on the NPRS has been considered to reflect the MCID in patients with LBP, indicating that any change equal to or greater than this value can be considered clinically relevant. However, the MCID has not yet been established in patients with LBRLP and neuropathic characteristics; therefore, a variation of 2 points will be used as a reference value, as in patients with LBP and those with chronic pain in general.
Baseline, immediately after the intervention and 1 week post-intervention.
Secondary Outcomes (10)
Disability
Baseline and 1 week post-intervention.
Health-related quality of life
Baseline and 1 week post-intervention.
Neuropathic component of pain
Baseline and 1 week post-intervention.
Pressure pain threshold
Baseline, immediately after the intervention and 1 week post-intervention.
SLR test outcome
Baseline, immediately after the intervention and 1 week post-intervention.
- +5 more secondary outcomes
Other Outcomes (1)
Sociodemographic variables
Baseline.
Study Arms (4)
Real PENS + Placebo TENS
EXPERIMENTALParticipants will receive real ultrasound-guided dry needle insertion (0.30 mm × 60 mm and 0.30 mm ×50 mm) to the perineural region adjacent to the sciatic nerve at both the subgluteal fold and the posterior thigh (junction between the middle and distal thirds). Electrical stimulation will be applied using the Endomed 484® electrotherapy unit (PRIM Physio, Madrid, Spain) in continuous biphasic mode at low frequency (2 Hz), 250 μs pulse width for 30 minutes. Intensity will be adjusted to elicit a visible, mild muscle contraction. Simultaneously, adhesive electrodes will be placed near the intervention site but connected to a disabled channel to simulate placebo TENS.
Real TENS + Placebo PENS
ACTIVE COMPARATORParticipants will receive real superficial electrical stimulation via adhesive electrodes connected to the Endomed 484® unit, configured for TENS (non-invasive). Parameters will match those from Group 1 (continuous biphasic current, 2 Hz, 250 μs, 30 min), producing a clear sensory perception and mild muscle contraction. Simultaneously, a sham ultrasound-guided dry needling procedure will be performed using Streitberger placebo needles, which contact the skin superficially without penetration. Cables for PENS will be placed on the skin but connected to a disabled channel to simulate placebo PENS.
Real Dry Needling (without PENS) + Placebo TENS
ACTIVE COMPARATORParticipants will receive real ultrasound-guided dry needling as in Group 1 but without electrical stimulation. The needles will remain in place for 30 minutes, with the PENS channel disabled to act as placebo. Simultaneously, adhesive electrodes will be placed as in Group 1, with TENS channels disabled. Participants will be told the current is below the sensory threshold. The design of this intervention group aims to determine whether the therapeutic effects observed with the PENS technique are exclusively due to needle insertion (dry needling) or whether the passage of electrical current through the needle (as in Group 1) plays a decisive role in the outcomes obtained. To this end, real ultrasound-guided dry needling is applied at the same anatomical locations, but without activation of the electrical stimulation channel, the latter acting as a placebo. This comparison will allow the specific effect of electrical stimulation to be isolated within the context of the intervention.
Placebo PENS + Placebo TENS
PLACEBO COMPARATORParticipants will receive only sham interventions. Placebo PENS will be simulated with Streitberger needles (skin contact without penetration) and cable placement, and placebo TENS with adhesive electrodes connected to a disabled channel. Participants will be informed that current is below the sensory threshold. The procedure will last 30 minutes.
Interventions
Participants will receive real ultrasound-guided dry needle insertion (0.30 mm × 60 mm and 0.30 mm ×50 mm) to the perineural region adjacent to the sciatic nerve at both the subgluteal fold and the posterior thigh (junction between the middle and distal thirds). Electrical stimulation will be applied using the Endomed 484® electrotherapy unit (PRIM Physio, Madrid, Spain) in continuous biphasic mode at low frequency (2 Hz), 250 μs pulse width for 30 minutes. Intensity will be adjusted to elicit a visible, mild muscle contraction.
Adhesive electrodes will be placed near the intervention site (sciatic nerve between the subgluteal fold and the distal third of the thigh) but connected to a disabled channel to simulate placebo TENS.
Participants will receive real superficial electrical stimulation via adhesive electrodes connected to the Endomed 484® unit, configured for TENS (non-invasive). Parameters will include continuous biphasic current, 2 Hz, 250 μs, 30 min, producing a clear sensory perception and mild muscle contraction.
A sham ultrasound-guided dry needling procedure will be performed using Streitberger placebo needles, which contact the skin superficially without penetration. Cables for PENS will be placed on the skin but connected to a disabled channel to simulate placebo PENS.
Participants will receive real ultrasound-guided dry needling but without electrical stimulation. The needles will remain in place for 30 minutes, with the PENS channel disabled to act as placebo.
Eligibility Criteria
You may qualify if:
- Neuropathic-like LBRLP (sciatica).
- S-LANSS score ≥ 12 points.
- LBRLP lasting more than 6 months.
- Age between 18 and 70 years.
- LBRLP in the past 4 weeks has been severe enough to limit usual activities or change daily routines for more than 1 day.
- At least one period of 6 months to 1 year during which the participant did not go a full month without LBRLP.
- LBRLP intensity of at least 3/10 on the NPRS.
- Ability to provide informed consent.
You may not qualify if:
- Acute injury or recent major trauma history.
- Relevant painful conditions of the hip joint or pelvic/sacroiliac region.
- Symptoms compatible with cauda equina syndrome (loss of bladder/bowel control, sexual dysfunction, paralysis of lower limbs, etc.).
- Previous surgery on the spine, pelvis or hip.
- Prior treatment with anesthetic or anti-inflammatory blocks or with radiofrequency (facet, sacroiliac, radicular, epidural, etc.) in the past two years.
- Any neurological or systemic disease that could limit participation in the study.
- Inability to communicate in Spanish or understand study instructions and content.
- General contraindications for invasive physiotherapy and electrotherapy techniques.
Contact the study team to confirm eligibility.
Sponsors & Collaborators
Study Sites (1)
Hospital Universitario 12 de Octubre
Madrid, Madrid, 28041, Spain
MeSH Terms
Conditions
Interventions
Condition Hierarchy (Ancestors)
Intervention Hierarchy (Ancestors)
Study Design
- Study Type
- interventional
- Phase
- not applicable
- Allocation
- RANDOMIZED
- Masking
- TRIPLE
- Who Masked
- PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
- Purpose
- TREATMENT
- Intervention Model
- PARALLEL
- Sponsor Type
- OTHER
- Responsible Party
- SPONSOR
Study Record Dates
First Submitted
November 25, 2025
First Posted
January 29, 2026
Study Start
May 13, 2026
Primary Completion (Estimated)
December 1, 2026
Study Completion (Estimated)
November 1, 2027
Last Updated
May 14, 2026
Record last verified: 2025-11