Phantom Exercise for Lower Limb Amputees

An amputation is a distressing event that will result in physical, psychological, and social consequences. The loss of limb means a huge impact, not only for the patient's body and the way he notices it, as well as the perception of the environment around him. Most of the patients with lower extremity amputations experienced phantom limb pain. It is defined by painful sensation in the missing limb. According to a recent study, the prevalence of phantom limb pain ranges from 45% to 85%. Regardless of the reason for amputation, phantom limb pain diminishes over time in most cases. However, in about 5-10% of amputees' severe pain persists for several years. It affects the patient's capacity for self-care and personal independence as it is mentally and physically debilitating. Incidence of PLP in recent studies is reported to be approximately 42.2-78.8% of amputees. It should be noted that phantom limb pain (PLP) differs from pain in the stump called residual limb pain (RLP), which is due to skin complications, vascular compromise, inappropriate healing, painful neuromas, excess soft tissue and bone irregularities.

However, the exact mechanism of phantom limb pain is unknown, but advancement in pain physiology indicates that multiple mechanisms are involved including peripheral, spinal and supraspinal mechanisms. The first changes may take place in the periphery where the nerve endings are sensitized by pre-amputation pain and nerve transection. But the complexity of phantom phenomena and the association between catastrophizing and phantom limb pain indicate that supraspinal changes play a significant role in phantom pain. It is likely that the relative contributions of these mechanisms vary from one amputee to another and that they may change over time in the individual patient.

It has been seen that phantom limb pain is typically experienced in regions with large cortical representation, such as the hands/fingers and feet/toes. The pain is often described with words such as knifelike, sticking, pricking, shooting, and burning. Both PLP and RLP have a high incidence among amputees. These pains are a continual reminder of circumstances and can affect important factors of Quality of life such as sleep, fatigue mood and relationships compromising the acquisition of skills and quality of life. Thus, interfering with the physical and psychosocial rehabilitation of the amputee. This should be considered clinically during therapeutic encounters, and amputees should be given appropriate information on these potential associations, though often neglected by the medical team. Although QOL in amputees seems primarily determined by mobility impairment, pain, emotional perturbation, it is seen that physician-controlled factors such as the timing of amputation, informed decision making, and postamputation support may also play an important role. This data can be efficiently collected through limb deficiency and phantom limb questionnaire. During the rehabilitation process, multiple tools are available that help physicians to determine both motor ability and mobility in amputees as well as other determinants of quality of life and pain status of amputees. These include tests that determine motor ability as Single-limb standing balance test (Balance test), the Lower-Extremity Motor Coordination Test (LEMOCOT) and the Amputee Mobility Predictor without a prosthesis (AMPnoPRO). The AMP is a highly reliable instrument and it is relatively easy to administer in 15 minutes or less. Patients characteristics can be easily evaluated using "Limb Deficiency and Phantom Limb Questionnaire (Questionnaire 2008, Version 2)" and visual analogue scale (VAS) for the presence and extent of PLP. Health-related quality of life (HRQL) will be measured by the SF-36 questionnaire.

Despite a growing body of evidence, phantom limb pain remains a challenging condition to treat. There remains a large potential for innovation in improving the treatment strategies for these patients. More than 25 treatments for PLP are currently available yet not one is widely accepted or superior to others. Common self-treatment strategies can include wearing an elastic stump sock to minimise volume changes in the residual limb, stump massage, mental imagery of the phantom limb and taking physical exercise.

A rehabilitation technique that proved promising in recent years is mirror therapy, which involves a mirror being placed in a position that allows the patient to view a reflection of a body part. whilst the nonpainful limb is placed in front of the mirror so that it creates a reflection that can be seen by the patient, the stump is kept behind the mirror. In amputees, this creates the illusion of having two intact limbs and then the patient is asked to move an intact limb in certain patterns. This gives the illusion that the painful limb can move normally too. The mechanism of action of mirror therapy remains uncertain, with the reintegration of motor and sensory systems, restored body image and control over fear-avoidance likely to influence the outcome. Nevertheless, mirror therapy is inexpensive, safe and easy for the patient to self-administer but the level of evidence is insufficient. A limitation of the mirror box technique is the poor verisimilitude of the sensory feedback provided from the missing limb. The participant may have the visual illusion that the phantom extremity is moving, but the apparatus is crude and the illusion often not compelling. Patients cannot independently control the mirrored extremity, so only symmetric actions can be modelled.

Moreover, a relatively less researched method of reduction of phantom limb pain is Phantom exercises (PE). This involved imagining moving the phantom limb and then attempting to perform a few movements. The neurophysiological network activated during phantom limb movements is similar to that of executed movements of intact limbs and differs from the phantom limb imagination network. The dual ability of amputees to execute and imagine movements of their phantom limb and the fact that these two tasks activate distinct cortical networks are important factors to consider when designing rehabilitation programmes for the treatment of phantom limb pain. Few studies indicate that phantom exercises can be used safely to alleviate phantom limb pain in lower and upper limb amputees.

The evidence for clinical efficacy of mirror therapy is encouraging, but not yet definitive. Virtual reality could be a substitute for mirror therapy especially in the case if person suffers from bilateral amputation but even though the use of an immersive virtual reality (VR) environment may have a short-term effect on PLP for the majority of amputees who experience PLP, it's cost remain a problem in developing country like Pakistan, Moreover, because of high prevalence and high pain intensity of phantom limb pain, there is need to find an effective, easily administered home-based treatment for amputees, thus comparing effects of mirror therapy with and without phantom exercises in reducing pain and improving QOL and psychological status of amputees is a useful guide for future studies as these protocols are cost-effective and efficient.

In a pilot, study authors investigated the effects of phantom limb exercises on phantom limb pain. A total of 20 traumatic amputees participated in the study. Ten received phantom exercises and prosthetic training, and 10 were treated with routine prosthetic training and a general exercise programme. They found that pain intensity decreased in all subjects after 4 weeks of treatment in both groups. according to the visual analogue scale scores at the end of 4 weeks, the phantom exercises group differed significantly from the general exercise group. Thus, the study indicated that phantom exercises can be used safely to alleviate phantom limb pain in lower and upper limb amputees.

This study combines the effect of mirror therapy with phantom exercises in the experimental group. Similarly, another randomized controlled trial (RCT) was done to evaluate the reduction in phantom pain and sensation with combined training of progressive muscle relaxation, mental imagery and phantom exercises. This randomized controlled prospective trial with two parallel groups included Fifty-one subjects with unilateral lower limb amputation with Phantom Limb Pain. The experimental group performed combined training of progressive muscle relaxation, mental imagery and phantom exercises 2 times a week for 4 weeks, while the control group had the same amount of physical therapy dedicated to the residual limb. The results showed a significant decrement over time in all the Patient evaluation questionnaire domains (both in terms of phantom limb sensation (PLS) and phantom limb pain (PLP) and Brief pain intensity in experimental groups. The conclusion of this suggested that combined training of progressive muscle relaxation, mental imagery and modified phantom exercises should be taken into account as a valuable technique to reduce phantom limb pain and sensation. As Mirror therapy (MT) has been proposed as an effective rehabilitative strategy to alleviate pain symptoms in amputees with phantom limb pain (PLP) so in this study mirror therapy is used as conventional treatment along with the general exercise programme for amputees.