Clinical Application Observation on the Evaluation of Phantom Limb Pain With the Suralis System

Clinical Application Observation: Evaluation of Phantom Limb Pain After 3 Weeks of Use of a Feedback System Using Vibration (Suralis, Manufacturer: Saphenus)

This study tests whether a vibration-based feedback device (Suralis) can reduce phantom limb pain in people with lower-leg amputations over 3 weeks. Participants wear the device daily and report pain levels, walking ability, and quality of life - with no known risks, as it's a CE-certified medical device. If pain improves, the study team will help participants apply for insurance coverage to keep using the system long-term. The goal is to offer a simple, non-drug option that may help ease chronic pain and improve daily function for amputees. Participation is voluntary and can be stopped anytime without affecting medical care.

Study Overview

• Status: Recruiting
• Conditions: Lower Limb Amputation Knee; Lower Limb Amputation Below Knee; Lower Limb Amputation Above Knee; Phantom Limb Pain After Amputation
• Intervention / Treatment: Device: Vibrotactile sensory feedback

Detailed Description

This observational, prospective, single-arm pilot study evaluates the short-term effects of the Suralis vibrotactile feedback system (Saphenus Medical Technology GmbH) on phantom limb pain intensity, gait stability, and perceived quality of life in individuals with unilateral lower-limb amputation. The Suralis system consists of a sensorized insole with four pressure-sensitive zones (toe, forefoot, midfoot, heel), each mapped to a corresponding vibrotactile actuator embedded in a thigh-mounted cuff. Vibration parameters - including onset threshold, intensity (0-100 % amplitude), duration (50-500 ms), and spatial mapping - are individually calibrated via a proprietary iOS/Android app, allowing for personalized somatosensory substitution. The system operates autonomously during ambulation.

The study protocol includes a 3-week baseline phase to confirm persistent phantom pain (VAS ≥ 3/10 daily), followed by 3 weeks of active intervention, and a 3-week washout/follow-up phase to assess sustainability of effects. All assessments are conducted at the study center and include standardized functional tests (TUG, 6MWT), validated German-language questionnaires (DSF, VR-12, DASS, FW7, GCPS), and daily VAS entries captured via paper-based diaries. The system's CE-marked status (UDI: FBS 1 912012142) confirms conformity with EU MDR 2017/746 for Class IIa medical devices; no adverse events related to device use have been reported in prior clinical use. The study design incorporates no control group or randomization, reflecting its exploratory, real-world application focus. Statistical analysis will be descriptive and exploratory, with non-parametric methods applied to ordinal outcomes (Friedman test) and parametric or non-parametric repeated-measures analyses for continuous variables, depending on distribution. No blinding is feasible due to the nature of the intervention. All procedures comply with the Declaration of Helsinki and have been reviewed by the Ethics Committee of the Hessian Medical Association (approval pending).

• Study Type: Interventional
• Enrollment (Estimated): 20
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Johannes Schroeter, Dr. med.; Phone Number: +49 611 575 811; Email: johannes.schroeter@median-kliniken.de
• Study Contact Backup: Name: Natascha Raisig, M. Sc.; Phone Number: +49 611 575 87294; Email: natascha.raisig@median-kliniken.de

Study Locations

• Germany
  • Hesse
    • Wiesbaden, Hesse, Germany, 65191
      • Recruiting
      • MEDIAN Rehab Center Wiesbaden Sonnenberg
      • Contact: Johannes Schroeter, Dr. med.; Phone Number: +49 611 575 811; Email: johannes.schroeter@median-kliniken.de

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Unilateral major lower-limb amputation (transtibial or transfemoral)
• Presence of persistent phantom limb pain, defined as daily pain intensity ≥ 3/10 on the Visual Analog Scale (VAS) during the baseline period
• Regular daily use of a prosthetic limb (minimum 4 hours/day)
• Adequate German language proficiency to understand and complete study questionnaires and follow study procedures
• Ability to provide informed consent

Exclusion Criteria:

• Unstable wound or skin condition at the residual limb
• Inconsistent prosthetic use (less than daily or < 4 hours/day)
• Poorly fitting or non-functional prosthesis (as determined by study team)
• Incapacity to provide informed consent (e.g., due to cognitive impairment or severe psychiatric illness)
• Insufficient German language skills to comprehend study materials or complete assessments reliably

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Intervention with Suralis System; All participants receive a 3-week intervention with the Suralis vibrotactile feedback system, which provides real-time pressure-based sensory feedback via a sensorized insole and thigh-mounted vibrating cuff, calibrated individually via smartphone app to support pain reduction and gait stability.

Device: Vibrotactile sensory feedback; The Suralis system delivers real-time vibrotactile feedback via four pressure sensors embedded in a prosthetic insole, each mapped to a corresponding vibration motor on a thigh cuff. Participants wear the device during daily ambulation for 3 weeks. Vibration parameters (threshold, intensity, duration, spatial mapping) are individually calibrated via a smartphone app to match each user's sensory perception and gait pattern. The system operates autonomously, requires daily charging, and logs usage data via Bluetooth. No additional therapy or medication is administered alongside the device. The intervention aims to modulate cortical reorganization and reduce phantom limb pain while improving gait confidence and safety, particularly under non-visual conditions (e.g., stepping backward or sideways). The device is CE-marked (UDI: FBS 1 912012142) and classified as a Class IIa medical device under EU MDR 2017/746.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Visual Analogue Scale (VAS)	Scores range from 0 to 100 mm, where 0 mm = "no phantom pain" and 100 mm = "worst imaginable phantom pain"; higher scores indicate greater pain intensity.	Baseline (t1), end of 3-week intervention (t3), and 3-week follow-up (t4) - assessed via daily VAS entries averaged per time point.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
German Pain Questionnaire DSF - subscales	A validated, German-language questionnaire that captures pain intensity, quality, chronicity (GCPS), well-being (FW7), psychological status (DASS) and health-related quality of life (VR-12).	Baseline (t1), end of 3-week intervention (t3), and 3-week follow-up (t4) - completed in person at study center.
Timed Up-and-Go (TUG) test	Measures dynamic balance and fall risk by timing how long a person rises from a chair, walks 3 m, turns, returns and sits down.	Baseline (t1), end of 3-week intervention (t3), and 3-week follow-up (t4) - performed once per visit at study center.
6-Minute Walk Test (6MWT)	Assesses ambulatory endurance by recording the total distance walked (meters) in six minutes on a 12-m circuit.	Baseline (t1), end of 3-week intervention (t3), and 3-week follow-up (t4) - performed once per visit at study center; distance in meters recorded.

Collaborators and Investigators

• Sponsor: Median

Publications and helpful links

Helpful Links

• Related Info

Study record dates

Study Major Dates

• Study Start (Actual): April 1, 2025
• Primary Completion (Estimated): July 31, 2026
• Study Completion (Estimated): July 31, 2026

Study Registration Dates

• First Submitted: December 23, 2025
• First Submitted That Met QC Criteria: December 23, 2025
• First Posted (Actual): January 7, 2026

Study Record Updates

• Last Update Posted (Actual): January 7, 2026
• Last Update Submitted That Met QC Criteria: December 23, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: Pain management; Phantom limb pain; Lower limb amputation; Vibrotactile feedback; Suralis system
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Nervous System Diseases; Postoperative Complications; Pathologic Processes; Neurobehavioral Manifestations; Perceptual Disorders; Pain, Postoperative; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Agnosia; Phantom Limb
• Other Study ID Numbers: PhantomLimbPain

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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