Reduction of Phantom Limb Pain and Improved Proprioception through a TSR-Based Surgical Technique: A Case Series of Four Patients with Lower Limb Amputation

[Innovative noninvasive gait-synchronized vibrotactile feedback system : "I can feel myself walking again"]

Despite intensive research and development of systems for restoration of sensory information, these have so far only been the subject of study protocols. A new noninvasive feedback system translates pressure loads on the forefoot and hindfoot into gait-synchronized vibrotactile stimulation of a defined skin area. To increase the authenticity, this treatment can be supplemented by a surgical procedure. Targeted sensory reinnervation (TSR) describes a microsurgical procedure in which a defined skin area on the amputated stump of the residual limb is first denervated and then reinnervated by a specific, transposed sensory nerve harvested from the amputated part of the limb. This creates a sensory interface at the residual stump. This article presents the clinical and orthopedic technical treatment pathway with this innovative vibrotactile feedback system and explains in detail the surgical procedure of TSR after amputation of the lower limb.

[Diagnostics and surgical treatment of painful neuromas]

BACKGROUND

Painful neuromas that often develop after peripheral nerve injury require adequate diagnosis and treatment because of the suffering they cause. The scientific basis for the development of painful neuromas has not yet been sufficiently investigated. In addition to conservative procedures, a larger number of surgical techniques are available for treatment of painful neuromas.

OBJECTIVE

A review of the basic principles, diagnostic and treatment options for painful neuromas.

MATERIAL AND METHODS

Presentation of the scientific basis regarding the development of painful neuromas. Illustration and discussion of the most common diagnostic and treatment procedures.

RESULTS

The scientific basis regarding the development of painful neuromas after peripheral nerve injury has not yet been adequately developed. In order to be able to make a correct diagnosis, the use of standardized diagnostic criteria and adequate imaging techniques are recommended. In the sense of a paradigm shift, the use of the formerly neuroma-bearing nerve for reinnervation of target organs is to be preferred over mere burying in adjacent tissue.

CONCLUSION

In addition to standardized diagnostics the management of painful neuromas often requires a surgical intervention after all conservative therapeutic measures have been exhausted. As an alternative to restoring the continuity of the injured nerve, targeted reinnervation of electively denervated target organs by the formerly neuroma-bearing nerve is preferable over other techniques.

Investigation of the correlation between knee joint position sense and physical functional performance in individuals with transtibial amputation

INTRODUCTION

In individuals with transtibial amputation, the distal part of the lower extremity is lost. Therefore, the knee joint is of greater importance to be able to provide physical performance. The aim of this study was to evaluate the correlation between knee joint position sense and physical functional performance in individuals with transtibial amputation.

METHODS

The study included 21 subjects with transtibial amputation. A digital inclinometer was used to evaluate the joint position sense of the amputated side knee joint. The timed up and go test, the 4-square step test, and 10-m walk test were used to evaluate physical functional performance. Linear regression analysis was used to investigate the associations between independent variables and functional performance tests.

RESULTS

The mean age of the participants was 52.52 ± 15.68 years. The mean of the error in knee joint position sense was 5.33 degree (standard deviation = 3.08 degree). The error in knee joint position sense of the amputated limb predicted 45% of the variance in the 4-square step test and 22% of the variance in the 10-m walk test ( P < 0.05).

CONCLUSIONS

The knee joint position sense on the amputated side was found to be associated with physical functional performance in individuals with transtibial amputation. Residual limb knee joint position sense should be considered when prescribing prostheses and planning rehabilitation programs.

Vibrotactile Feedback for a Person with Transradial Amputation and Visual Loss: A Case Report

Background and Objectives: After major upper-limb amputation, people face challenges due to losing tactile information and gripping function in their hands. While vision can confirm the success of an action, relying on it diverts attention from other sensations and tasks. This case report presents a 30-year-old man with traumatic, complete vision loss and transradial left forearm amputation. It emphasizes the importance of restoring tactile abilities when visual compensation is impossible. Materials and Methods: A prototype tactile feedback add-on system was developed, consisting of a sensor glove and upper arm cuff with related vibration actuators. Results: We found a 66% improvement in the Box and Blocks test and an overall functional score increase from 30% to 43% in the Southampton Hand Assessment Procedure with feedback. Qualitative improvements in bimanual activities, ergonomics, and reduced reliance on the unaffected hand were observed. Incorporating the tactile feedback system improved the precision of grasping and the utility of the myoelectric hand prosthesis, freeing the unaffected hand for other tasks. Conclusions: This case demonstrated improvements in prosthetic hand utility achieved by restoring peripheral sensitivity while excluding the possibility of visual compensation. Restoring tactile information from the hand and fingers could benefit individuals with impaired vision and somatosensation, improving acceptance, embodiment, social integration, and pain management.

Regenerative peripheral nerve interface reduces the incidence of neuroma in the lower limbs after amputation: a retrospective study based on ultrasound

BACKGROUND

Amputees suffer from symptomatic neuroma and phantom limb pain. Regenerative peripheral nerve interface (RPNI) has recently been regarded as an effective method to prevent neuroma after amputation. However, the verifications of RPNI efficacy are mostly based on subjective evaluation, lacking objective approaches. This study aims to unveil the effect of RPNI on preventing neuroma formation and provide evidence supporting the efficacy of RPNI based on ultrasound.

METHODS

Amputees of lower limb at Peking University People's Hospital from July 2020 to March 2022 were analyzed retrospectively. The clinical data collected consisted of general information, pathology of primary disease, history of limb-salvage treatment, amputation level of nerve, pain scales such as the Numerical Rating Scale (NRS) and the Manchester Foot Pain and Disability Index (MFPDI). Three months after amputation, the transverse diameter, anteroposterior diameter, and cross-sectional area of neuromas in stump nerves at the end of residual limbs were measured using ultrasound and compared to adjacent normal nerves.

RESULTS

Fourteen patients were enrolled in the study, including 7 in the traditional amputation group (TA group) and 7 in the RPNI group. There was no significant difference in basic information and amputation sites between the two groups. The NRS and MFPDI scores of patients in RPNI group were significantly lower than those in TA group, and decreased with the follow-up time increasing, indicating that RPNI could reduce symptomatic neuroma pain. The comparison of preoperative ultrasound and postoperative pathology showed ultrasound could reflect the size of neuroma in vivo. Independent-sample t tests indicated that the ratios of anteroposterior diameter, transverse diameter and area of the cross section of both the neuroma and adjacent normal nerve obtained via ultrasound were significantly reduced in the RPNI group.

CONCLUSION

This study suggested that RPNI can effectively prevent the formation of symptomatic neuroma after amputation using ultrasound.

Treating phantom limb pain: cryoablation of the posterior tibial nerve

Phantom limb pain (PLP) is a complex pathophysiologic process involving both the central and peripheral nervous system for which there is no definitive treatment. The number of individuals living with amputated limbs is predicted to increase to 3.5 million by 2050, and up to 80% of these patients will have PLP. In this case report, we will demonstrate successful reduction of PLP in a patient with bilateral phantom toe pain utilizing nerve blockade and subsequent cryoablation of the posterior tibial nerves.

Effectiveness of graded motor imagery protocol in phantom limb pain in amputed patient: Protocol of a randomized clinical trial

OBJECTIVE

The aim of this study is to analyse the effectiveness of the Graded Motor Imagery (GraMI) protocol in phantom limb pain in amputee patients.

MATERIALS AND METHODS

A randomised clinical trial will be conducted, with two parallel groups and simple blinding, and a phenomenological study with semi-structured interviews. People over the age of 18, with amputation of one limb, with a minimum score of 3 on the visual analogue scale of pain, who are pharmacologically stable and have been discharged from hospital, will be recruited. An initial assessment, a post-intervention assessment (9 weeks) and a follow-up assessment (12 weeks post-intervention) will be performed, in which pain, quality of life, functionality and psychological aspects will be assessed. The aim of the qualitative study is to find out about the experience of living with phantom limb pain and to identify the satisfaction with the intervention. A descriptive, univariate and bivariate quantitative statistical analysis will be performed using the SPSS program, with a 95% confidence level and a statistical significance level of p < 0.05. The qualitative analysis will be carried out using the Atlas.ti 8.0 program, where the different interviews will be analysed, coded and categorised.

DISCUSSION

The GraMI protocol allows the patient to work on motor learning through brain reorganisation, analytical movements, sensory stimulation, and functional activities. In addition, it can help to standardise the use of graded motor imagery in future studies and in clinical practice with this patient profile.

TRIAL REGISTRATION

NCT05083611.

Optimally-calibrated non-invasive feedback improves amputees' metabolic consumption, balance and walking confidence

OBJECTIVE

Lower-limb amputees suffer from a variety of health problems, including higher metabolic consumption and low mobility. These conditions are linked to the lack of a natural sensory feedback from their prosthetic device, which forces them to adopt compensatory walking strategies that increase fatigue. Recently, both invasive (i.e. requiring a surgery) and non-invasive approaches have been able to provide artificial sensations via neurostimulation, inducing multiple functional and cognitive benefits. Implants helped to improve patient mobility and significantly reduce their metabolic consumption. A wearable, non-invasive alterative that provides similar useful health benefits, would eliminate the surgery related risks and costs thereby increasing the accessibility and the spreading of such neurotechnologies.

APPROACH

Here, we present a non-invasive sensory feedback system exploiting an optimally-calibrated (JND-based) electro-cutaneous stimulation to encode intensity-modulated foot-ground and knee angle information personalized to the user's just noticeable perceptual threshold. This device was holistically evaluated in three transfemoral amputees by examination of metabolic consumption while walking outdoors, walking over different inclinations on a treadmill indoors, and balance maintenance in reaction to unexpected perturbation on a treadmill indoors. We then collected spatio-temporal parameters (i.e. gait dynamic and kinematics), and self-reported prosthesis confidence while the patients were walking with and without the sensory feedback.

MAIN RESULTS

This non-invasive sensory feedback system, encoding different distinctly perceived levels of tactile and knee flexion information, successfully enabled subjects to decrease metabolic consumption while walking and increase prosthesis confidence. Remarkably, more physiological walking strategies and increased stability in response to external perturbations were observed while walking with the sensory feedback.

SIGNIFICANCE

The health benefits observed with the use of this non-invasive device, previously only observed exploiting invasive technologies, takes an important step towards the development of a practical, non-invasive alternative to restoring sensory feedback in leg amputees.

[Targeted muscle reinnervation and targeted sensory reinnervation : Role of complex neurotization after amputation]

In association with major amputations of the upper and lower extremities, surgical procedures with nerve transfer are increasingly being introduced. In order to examine the value of these procedures the currently available data were analyzed and related to the corresponding insights from conventional amputation surgery as well as confirmed aspects of microsurgery of peripheral nerves. Mainly retrospective observations of low case numbers and sometimes individually different surgical approaches can be found. Risk analysis and sufficient long-term follow-up periods are lacking as well as comparisons with appropriate control groups. The published results on operative procedures with selected nerve transfers after or during amputation do not currently allow any conclusions about the advantages. Systematic influences in the assessment of the results are probable. Implementation of these treatment options outside controlled clinical trials cannot be recommended.

Wearable Technologies Using Peripheral Neuromodulation to Enhance Mobility and Gait Function in Older Adults - A Narrative Review

BACKGROUND

Mounting evidence suggests that wearable technologies using peripheral neuromodulation can provide novel ways of improving mobility and gait function in various patient populations including older adults. The purpose of this narrative review is to provide an overview of wearable technologies/devices to improve mobility and gait function through noninvasive peripheral neuromodulation in older adults over the age of 65 and to indicate the suggested mechanism of action behind these technologies.

METHODS

We performed searches for articles and conference abstracts written in English, using the following databases: Embase Classic+Embase from 1947 to July 15, 2021; Ovid MEDLINE®; Epub Ahead of Print, In-Process, In-Data-Review & Other Non-Indexed Citations, Daily and Versions® from 1946 to July 15, 2021; PubMed; and Scopus.

RESULTS

Forty-one technologies met the inclusion/exclusion criteria. We found that the primary implementation of the 41 technologies can be divided into three main categories: sensory substitution, sensory augmentation (open loop, closed loop), and motor stimulation. Using these technologies, various aspects of mobility are treated or addressed, including e.g., gait function, fall risk, foot drop, navigating environment, postural control.

CONCLUSIONS

This narrative review summarizes wearable technologies that are currently commercially available and in stages of research and development. Overall, studies suggest that wearable peripheral neuromodulation technologies can improve aspects of mobility for older adults. Existing literature suggests that these technologies may lead to physiological changes in the brain through sensory re-weighting or other neuroplastic mechanisms to enhance the performance of mobility and gait function in older adults over the age of 65.