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.
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
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)
Single group
Vibrotactile sensory feedback
DeviceThe 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.
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.
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).
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.
6-Minute Walk Test (6MWT)
Assesses ambulatory endurance by recording the total distance walked (meters) in six minutes on a 12-m circuit.
