Safety and Efficacy of Vibro-tactile Feedback for Patients Who Underwent Lower Limb Amputation

Prosthetics research has grown recently, focusing on bionic approaches that restore bodily functions with technical aids. One method involves using prostheses with feedback systems, which measure physical parameters and provide additional information to the user. Saphenus has developed a feedback system called Suralis© that transfers pressure signals from the prosthetic sole to another body region. This clinical investigation aimed to determine if this system improves gait stability and walking. The study analyzed changes in gait and functional balance and gathered patient-reported measures to evaluate the quality of life.

This research was open to individuals who have undergone below-knee amputation but no targeted re-innervation surgery and use prosthetics. Participants received the Suralis© feedback system, and the investigators assessed their walking activities. The system measures prosthetic foot sole pressure and converts it into digital signals, triggering vibration stimuli during the stance phase of walking. The investigators collected gait analyses and patient feedback to assess the impact of the feedback system on prosthetic management. The results will help us understand the benefits and effectiveness of this technology for people with amputation.

Study Overview

• Status: Terminated
• Conditions: Amputation of Lower Limb Below Knee; Unilateral
• Intervention / Treatment: Device: vibrotactile ground-contact feedback

Detailed Description

The investigators conducted a prospective, unblinded crossover trial to compare the effectiveness of a vibration intervention with no intervention. Participants were randomly assigned to one of two sequences: vibration intervention followed by no intervention or vice versa. The intervention involved using the Suralis© vibrotactile ground-contact feedback system for 60 days. The system transmitted ground contact information to the residual lateral thigh, providing sensory feedback. During the control phase, participants received no additional intervention. The washout period lasted seven days. The study collected data during four visits, assessing gait and patient-reported measures. Bayesian generalized linear mixed models were used for data analysis, considering fixed effects (intervention, sequence, and period) and random effects (individuality).

• Study Type: Interventional
• Enrollment (Actual): 18
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Austria
  • Vienna, Austria, 1030
    • Ordination Dr. Wolfgang Schaden

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• male, female, and diverse individuals
• unilateral transtibial amputation
• at least 18 months post surgery
• walking without aids possible
• signed informed consent form

Exclusion Criteria:

• insufficient thigh sensation to distinguish between the two closest vibrotactile actuators
• an acute event that restricts the walking ability
• interfering lesions or painful conditions
• undergone targeted re-innervation surgery
• poor stump condition
• used a non-modular prosthesis
• used a prosthesis in poor condition
• conditions preventing safe participation or interfering with study objectives
• not able to not comply with the protocol

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Supportive Care
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Control-Vibration; Participants were assessed before and after 60 days of no additional intervention to any ongoing treatment, after seven days of washout, and after receiving 60 days of vibrotactile ground-contact feedback.	Device: vibrotactile ground-contact feedback; Suralis®, Saphenus Medical Technology (Baden, Lower Austria, Austria)
Active Comparator: Vibration-Control; Participants were assessed before and after receiving 60 days of vibrotactile ground-contact feedback, after seven days of washout, and after 60 days of no additional intervention to any ongoing treatment.	Device: vibrotactile ground-contact feedback; Suralis®, Saphenus Medical Technology (Baden, Lower Austria, Austria)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Affected leg stance time treatment-change difference	Stance time of the prosthetic leg during walking over level ground and on a 518 cm instrumented walkway at a self-selected speed	Difference between the within-period changes of the 60-day control (C) and vibration (V) periods of the randomized controlled crossover trial, i.e., V(post - pre) - C(post - pre); three tries each assessment day

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Gait speed treatment-change difference	Average speed of walking over level ground and on a 518 cm instrumented walkway at a self-selected speed	Difference between the within-period changes of the 60-day control (C) and vibration (V) periods of the randomized controlled crossover trial, i.e., V(post - pre) - C(post - pre); three tries each assessment day
Unaffected leg step length treatment-change difference	Step length of the non-prosthetic leg during walking over level ground and on a 518 cm instrumented walkway at a self-selected speed	Difference between the within-period changes of the 60-day control (C) and vibration (V) periods of the randomized controlled crossover trial, i.e., V(post - pre) - C(post - pre); three tries each assessment day
Quality of life score treatment-change difference	EuroQol (EQ) 5-Dimension (5D) 3-Level (3L) version, visual analog scale (VAS)	Difference between the within-period changes of the 60-day control (C) and vibration (V) periods of the randomized controlled crossover trial, i.e., V(post - pre) - C(post - pre); once each assessment day
Adverse effects frequency treatment difference	Patient diary documentation and interview regarding adverse effects	Difference in the event frequency during the 60-day control (C) and vibration (V) periods of the randomized controlled crossover trial, i.e., V - C; once each assessment day
Timed up and go test time treatment-change difference	Stand up, walk 3 m, turn around, and sit down	Difference between the within-period changes of the 60-day control (C) and vibration (V) periods of the randomized controlled crossover trial, i.e., V(post - pre) - C(post - pre); three tries each assessment day
2 min walk test distance treatment-change difference	Walking distance in meters within a 2 min time frame	Difference between the within-period changes of the 60-day control (C) and vibration (V) periods of the randomized controlled crossover trial, i.e., V(post - pre) - C(post - pre); once each assessment day
Four square step test time treatment-change difference	Do and reverse four steps over 90 cm long canes arranged in a cross configuration on the ground	Difference between the within-period changes of the 60-day control (C) and vibration (V) periods of the randomized controlled crossover trial, i.e., V(post - pre) - C(post - pre); three tries each assessment day

Collaborators and Investigators

• Sponsor: Ludwig Boltzmann Institute for Traumatology - The research center in cooperation with AUVA
• Collaborators: Saphenus Medical Technology GmbH
• Investigators: Principal Investigator: Gerfried Peternell, MD, Ludwig Boltzmann Institute for Traumatology, The Research Center in Cooperation with the AUVA

Publications and helpful links

Helpful Links

• Data and Code

Study record dates

Study Major Dates

• Study Start (Actual): October 25, 2021
• Primary Completion (Actual): May 6, 2022
• Study Completion (Actual): May 6, 2022

Study Registration Dates

• First Submitted: May 19, 2023
• First Submitted That Met QC Criteria: May 31, 2023
• First Posted (Actual): June 8, 2023

Study Record Updates

• Last Update Posted (Actual): June 13, 2023
• Last Update Submitted That Met QC Criteria: June 9, 2023
• Last Verified: June 1, 2023

More Information

Terms related to this study

• Keywords: rehabilitation; lower limb amputation; functional balance; gait performance; somatosensory feedback; four square step test
• Other Study ID Numbers: IPS002

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: All individual participant data that underlie results in the main publication
• IPD Sharing Time Frame: At the time of acceptance in a scientific journal
• IPD Sharing Access Criteria: The investigators aim to provide broad, equitable, and maximally open access to the dataset and their metadata free of charge in a timely manner after acceptance, consistent with legal and ethical limits required to maintain privacy and confidentiality, tribal sovereignty, and protection of other sensitive data.
• IPD Sharing Supporting Information Type: ANALYTIC_CODE

Study Data/Documents

1. Individual Participant Data Set
   Information comments: The investigators will migrate the dataset and code to a publisher-accepted and open repository once the manuscript is accepted for publication

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No