The Historical Evolvement of Movement and Exercise Training in Patients with Severe Burns and Their Potential Effects on Grafts, Scars, and Function

Abstract

Exercise training for burn patients has become a major part of rehabilitation programs within the last decades. One of the main reasons for prolonged and long-term increased morbidity and mortality in this population is a persistent catabolic state with subsequent loss of lean body mass (LBM). A combination of resistance and aerobic exercises as well as stretching has shown to improve physical function by enhancing cardiopulmonary fitness, LBM, and strength and thus leading to ameliorated long-term outcomes of patients recovering from burns. In this literature review, we show an outline of the implementation of exercise training over the last decades into standardized care for patients with burns.

Among the most severe long-term complications experienced by burn patients that increase morbidity and mortality are the loss of lean body mass (LBM) and prolonged muscle weakness. The body's catabolic response to a severe burn results in long-term functional impairment, decreased range of motion (ROM), scar contracture formation, and poor quality of life. Survivors face a long recovery process and need high-quality rehabilitation. Exercise training positively affects recovery and improves LBM, cardiorespiratory function, and muscle strength, thereby resulting in an overall improvement in the quality of patient's lives in both burned children and adults. ^{1 2 3}

However, many modes of physical activity are classified as “exercise,” ranging from stretching, to aerobic, to resistance. Generally, one of the most important goals of these activities is to restore functional capacity and for the patient to regain independence. ⁴ This concise review paper presents historical excerpts detailing the evolution of exercise training in burn care and highlights the complex path to establishing exercise as standardized therapy for burns rehabilitation. Finally, we conclude with potential concepts and innovations for the future.

In this review, we define exercise training as a combination of resistance training (building muscle strength and endurance), flexibility training (to increase ROM), and aerobic training (to improve cardiorespiratory function), in accordance with recommendations from the American College of Sports Medicine regarding training in healthy adults. ⁵

Methodology

In September 2023, a literature search was conducted in the Medline database via the Ovid interface to identify relevant literature using a variety of search terms and synonyms encompassing burns and exercise and the historical context and future methodologies of burn patient care. The purpose of the search was to ensure that all relevant literature on burns, exercise treatments, and healing outcomes were recognized in addition to relevant literature on the history of burn care or future trends or technologies of burn treatments as well. We chose studies conducted in adult and pediatric burn patients that were involved in inpatient or outpatient programs. We focused on graft success, scarring, and physical function as main outcomes.

1971

In 1971, when a minimum of 1-week bed rest with elevation of the affected limb following graft surgeries was common practice, Bodenham and Watson ⁶ conducted a pilot trial with 25 patients, in which early mobilization was allowed 48 hours after surgery. Although the study did not include burn patients, the findings of the study were crucial for changing how postsurgical movement was viewed with respect to graft take. When early mobilization followed lower limb graft surgery, 12 patients were discharged within 2 weeks and 9 patients within 3 weeks following surgery. Partial graft loss occurred in only three patients, where the graft crossed an adjacent joint, which was inadequately immobilized. In those patients, mobilization caused hematomas and/or seromas that consecutively led to the necessity of a revision surgery.

1982

A survey and series of case reports carried out by Harnar et al ⁷ in 1982 assessed clinical practice of early ambulation with a gelatin boot with an elastic bandage as the postoperative dressing in the 67 largest burn centers within the United States. The overarching goal was to evaluate the time of ambulation of patients who underwent small leg grafting below the knee. The results of the survey revealed that only 8% (5/61) of burn centers involved did ambulate their patients on day 1 postsurgery, whereas the majority started ambulation 5 days after surgery. Summarized, Harnar et al ⁷ suggested early ambulation (1-day postsurgery) for patients with lower extremity skin grafting if meshed and protected with the “Unna boot,” a historical dressing method for varicose ulcers, invented by the German dermatologist Dr. Paul Gerson Unna. ⁸

1984

Phyillis C. Wright promoted the importance of assessing ROM for all joints (even noninjured joints), structural gait analysis, daily activities, and strength measurement of all major muscle groups before initiation of therapy. An early promoter of personalized therapy, she suggested that different forms of exercise be combined, individually tailored to the patient's needs and limitations, including active, active-assisted, stretching, passive, and resistive exercises as well as proprioceptive neuromuscular facilitation. Contrary to later opinions she repeatedly pointed out that freshly grafted areas should not be mobilized. For patients suffering from severe pain, she suggested a passive therapy session shortly before surgeries as the patients were already anesthetized. ⁹

1985

A survey of compliance with physical and occupational therapy recommendations in burn patients was carried out by Ekes and Marvin ¹⁰ in 1985, approaching 90 burn centers in the United States and in Canada. A surprising finding was that therapists used “scare tactics” by confronting patients with pictures of contractures to increase their compliance. The results of the survey showed that compliance in general was reduced, especially for ROM and stretching exercises. The authors emphasized the importance of multidisciplinary collaboration between subspecialties in strengthening a patient's self-motivation. Child psychologists, child life specialists, and social workers should be involved, especially when working with pediatric burn patients.

1986

Heterotopic ossification, the growth of bone in nonskeletal tissue, is discussed as a complication of burn in a retrospective analysis by Crawford et al. ¹¹ Twelve of 1,066 patients with 20 to 85% of their total body surface area (TBSA) burned developed this complication in the elbow joint within an average period of 12 weeks' postburn. It is worth noting that the bone formation occurred only posterior to the joint, never anterior. Confirmation of the diagnosis using X-ray is necessary. Heterotopic ossification of the joint leads to a decreased ROM and consecutive functional disability accompanied by pain in movement. However, there was a remarkable difference in the appearance of the heterotopic ossification: patients who underwent passive- and active-assisted ROM training (out of the range of pain-free movement) showed to be affected by this complication, whereas “patients who followed a program of active exercise within the pain-free range gained excellent ROM.” In severe cases that led to complete ankylosis, surgical intervention was required.

2000

Silverberg et al ¹² critiqued the practice of evaluating gait in burn patients by clinical observation. To obtain more precise and examiner-independent data, the investigators in this study used the GAITRite computerized gait analysis system (CIR Systems Inc., Clifton, NJ) to capture more meaningful data by classifying footfall characteristics as temporal variables or spatial variables, dependent on time or distance, respectively. These findings are summarized as temporal and spatial gait variables. Using this approach, they were able to demonstrate that survivors with burns affecting the lower extremities had different gait patterns than the control group.

2011

Ebid et al ² found that for patients with burns ≥ 35% of TBSA, 6 months after burn, muscle weakness persisted when compared with healthy age-matched subjects. Reevaluation 9 months' postburn revealed a significant improvement when subjects adhered to a 12-week isokinetic protocol. Three months of isokinetic training for three times weekly increased muscle strength by 17.9 ± 10.1% (mean ± standard deviation) compared with the baseline measurement in burn patients. However, muscle strength in burn survivors continued to lag behind that of age-matched nonburned volunteers. At that time there was already consensus on the benefits of isokinetic training, supported by numerous studies in pediatric patients. ^{13 14}

2010 to 2020

The importance of providing effective rehabilitation was demonstrated by a matched case-controlled study from Grisbrook et al ¹⁵ testing a 12-week functional, goal-based program that combined resistance exercise and interval training in adult burn patients at least 2 years' postburn and with ≥ 20% of TBSA burned. Quality of life was assessed with a health-related quality of life (HRQOL) instrument, both before and after the 12-week program. The burn-specific health scale, which was developed to specifically assess impairments in the life of burn survivors, was also used. A decrease in activity limitations and a significant improvement in HRQOL was reported.

Compelling evidence supporting the need for combined exercise training including aerobic and resistance training exists. ^{15 16 17 18} Paratz et al ¹⁶ showed that after grafting, a 6-week supervised training program significantly improved psychological, physical, and functional measures in burn survivors. This was one of the first studies to investigate the effect of exercise training on HRQOL in both pediatric and adult burn patients. Based on the significant improvement in the intervention group, the authors recommended mandatory exercise training according to a standardized scheme.

Despite the plethora of studies on exercise in burns, consistent guidelines ¹⁴ translating research into practice by recommending the extent to which exercise training should be incorporated into rehabilitation did not exist. In fact, enrollment in outpatient exercise rehabilitation programs was not usual care. Evaluation of therapeutic success also varied, preventing comparison of exercise modalities across studies. Often used parameters to assess and monitor patient's physical function were and still are ROM, manual muscle testing, and quality of life, mostly due to the ease of implementation. However, more precise statements, especially regarding cardiorespiratory fitness, can be made by measuring the peak oxygen uptake (peak VO2), which may be avoided due to the associated complexity and expense. ⁴ Porro et al ¹⁹ provided a formula to estimate peak VO2 in burned children that relies on clinical parameters and can be determined using only a treadmill. Another affordable option was suggested by Stockton et al ²⁰ by assessing aerobic capacity in adults using a modified shuttle walk test.

In a systematic review and meta-analysis, Flores et al ¹⁷ found that consistent improvements in physical fitness and function, body composition, and contracture release surgeries occurred with exercise training in survivors of severe burns.

Lee et al ¹⁸ focused on the connection between intensive physical exercise (IPE), defined as a 12-week program of progressive, resistive, and aerobic exercises, and contracture-release surgeries in children with burns covering ≥ 40% of TBSA. They reported a reduction of approximately 60% for re-release procedures in the interventional group compared with non-IPE patients. The underlying mechanisms are not clear but warrant further investigation.

2021 to Present

A meta-analysis and systematic review conducted by Lagziel et al ²¹ identified the necessity of a burn related protocol named “Enhanced Recovery After Burn Surgery” as a special form of the enhanced recovery after surgery (ERAS) concept in use since 1997. ERAS was developed by Henrik Kehlet for use following colorectal surgeries; it is a multidisciplinary approach focused on reducing postoperative complications and shortening recovery time. In burns, consideration of the complexity of associated challenges that come with a burn injury is necessary, including acute and long-term rehabilitation, acute management including resuscitation, management of fluids, pain management, intensive care unit (ICU) treatment, nutritional requirements, etc. ²² Implementation of early mobilization for burn patients results in the reduction of hospital-acquired infections and shortened length of stay according to Lagziel et al. ²¹ These results indicate the need for further prospective studies.

In the latest guidelines of the American Burn Association (ABA), Cartotto et al ²³ noted the lack of a clear consensus regarding the effect of early physiotherapy intervention on graft outcomes in critically ill burn patients. As emphasized by the authors, at the present time, the evidence is insufficient to determine whether early mobilization and rehabilitation (EMR) leads to skin graft or skin substitute loss among critically ill adult burn patients in an ICU setting. We believe that further elucidation is needed.

Cartotto et al ²³ also reported the effect of EMR on the development of delirium. The absence of interventional studies on that topic led to recommendations based on existing literature regarding general medicine and medical intensive care. In the ICU, mobility has been shown to prevent delirium in a small number of studies, leading to a conditional recommendation endorsed by the ABA to utilize EMR as a preventative method in the burn ICU. However, the absence of interventional studies in burn patients underscores the necessity of further investigations in this population. In addition, the guideline addressed the impact of EMR on the development of intensive care unit-acquired weakness (ICUAW), leading to a conditional recommendation that EMR should be utilized to alleviate ICUAW in the adult burn ICU despite the dearth of evidence in the literature. ²³

Summary

Good communication between the medical, rehabilitation, and nursing staff is mandatory to determine whether early mobilization is safe and feasible in an individual critically ill burn patient. In order to obviate detrimental effects, however, respiratory, cardiovascular, hematological, functional, neurological, and external factors should be considered before enrolling patients in a training plan. ²⁴

A survey performed in Canada referring to nonburn ICU patients revealed that physiotherapists prioritized early mobilization more than physicians. It also showed that 69% of the respondents (including physiotherapists and physicians) underrate the occurrence of ICUAW. Moreover, 60% felt not being trained enough to provide movement of patients that are still on a ventilator. ²⁵ Similar results have been reported by Dikkema et al with a survey of burn care health professionals. Eighteen percent of the respondents complained about the same problem and reported that they were not sufficiently trained to mobilize ventilated patients. ²⁶ In summary, these findings show that education and training around early mobilization in an interdisciplinary setting is urgently needed and should be promoted more strongly.

Future Directions

As pointed out in an article by Rivas et al ²⁷ there is a great need for prospective studies regarding exercise training and outcomes such as scarring and psychosocial consequences in burns with longer follow-up periods. There is a need for better understanding of the mechanisms underlying how exercise training reduces scarring, especially in light of the finding that exercise training can prevent repeated surgical procedures.

Other movement modalities should also be integrated into the training programs. For example, yoga is a promising approach especially in burns of the chest, and pranayama breathing exercises have been shown to contribute to the therapeutic success within the context of physiotherapy. ²⁸

A one-time burn event cannot be adequately treated with a once-off therapy concept. Burn survivors need lifelong rehabilitation measures alongside well-thought-out plans that are logistically and financially feasible in the long term. This is where modern technology comes into play. Tailor-made apps for use by burn survivors could create individual training plans that could be integrated into everyday life. Virtual reality could also play a major role in increasing compliance and relieving pain for burn patients. ²⁹

Ultimately, in the age of robotic technology, innovative training expansions can be expected in the future. Joo et al were the first ones to investigate robot-assisted gait training in rehabilitation, showing positive effect on gait functionality and pain. No side effects were reported, making this supportive training option a promising development in the history of burn rehabilitation. ³⁰