Burn on the buttocks caused by gel wheelchair cushion left on driver’s seat of hand control car

Abstract

Context: Nowadays, people with paraplegia and quadriplegia have greater opportunities to venture into the general public. However, there is also an increased risk of associated hazards.

Findings: This report describes a 42-year-old man with paraplegia, who was insensate below the T7 level and sustained burns from sitting on a gel wheelchair cushion that had been left on the driver-side seat of a hand control car on a sunny day. Physical examination revealed deep partial-thickness burns on both his buttocks. He underwent surgical debridement and received an autologous split-thickness skin graft, and healed well.

Conclusion In modern times, the lives of people with paralysis are no longer restricted to the bed and wheelchair. Active people with spinal cord injuries inevitably diversify the use of wheelchair cushions in many ways; therefore, there is a greater possibility for the occurrence of associated hazards. This is a preventable issue, so both the user and manufacturers should recognize this potential hazard of gel wheelchair cushions.

Introduction

Currently, the widespread availability of barrier-free accessibility, advances in assistive devices, and the changes in social perception regarding handicapped people have increased the prospect of people with paraplegia and quadriplegia venturing into the general public. Hand control cars are one of the prime examples of such assistive devices. However, sometimes these assistive devices and society do not keep pace with the patient’s needs, which can lead to several hazards.

Here we report the case of a person with paraplegia who sustained burns on both buttocks from sitting on a gel wheelchair cushion that had been left on the hand control car driver’s side seat on a sunny day in the summer. No previous reports of burns caused by wheelchair cushions exist in the literature. This report is intended to bring attention to this issue to avoid occurrence of similar injuries in the future.

Patient

A 42-year-old man with long-standing paraplegia, who was insensate below the T7 level subsequent to a spinal injury resulting from a car accident 20 years ago, was referred to our department complaining of burns on the buttocks. He had a history of pressure injury at the sacrum and left ischium and received surgical treatment at our department three years previously; he had reported no problems since. He parked his hand control car with a gel wheelchair cushion on the driver’s side seat outside on a sunny day. Four hours later, although he noticed the gel was hot, he sat on the driver’s side seat and drove the car back home for approximately 30 min. It was not until he arrived home and removed his clothing that he learned that he had developed burns on his buttocks; he was subsequently referred to our department that night.

On physical examination, he was found to have deep partial-thickness burns on both buttocks, measuring approximately 8 × 14 cm [Figure 1 near here]. The finding that the lesions did not coincide with the bone projection, together with the traces of blisters on the lesions, indicated that the lesions were burns and not pressure ulcers. Upon closer questioning, considering the environmental circumstances, it was hypothesized that the cause of this burn was the heated gel wheelchair cushion. He was subsequently admitted to the hospital and treated conservatively at first. As he was keen for early recovery, he underwent surgical debridement with the application of an autologous split-thickness skin graft. His postoperative course was uneventful, and the burn healed well.

Figure 1.

Deep partial-thickness burns affecting both buttocks of the patient.

Discussion

Moritz and Henriquesx reported first- and second-degree thermal injuries in humans. Their data are the standard for the definition of thermal insult conditions that cause burn injury.^1,2 Though a contact temperature of 44°C requires almost 7 consecutive hours to cause a partial-thickness burn injury, a contact temperature of 50°C requires only 5 min.² Therefore, the contact temperature and contact time are important factors in thermal injuries.

Regarding contact temperature, short-wave radiation from the sun can increase the temperature inside a car to nearly 90°C, and the temperature of the car seat to 100°C.³ In addition, as the solar reflectance rate of the color black is low, black materials absorb sufficient heat with prolonged direct exposure to the sun. Thus, any black material inside a car on a hot sunny summer day heats up enough to burn the skin due to these synergistic effects.

The other factor in thermal injuries, contact time, is determined based on two factors: one involving the patient and the other, the material. As for the patient factor, children younger than 5 years, elderly persons, and disabled individuals, especially those with concomitant impairment of cutaneous sensation are included in the high risk group.⁴ Most people can detect and react to excessive heat; however, some individuals may not be able to move quickly upon exposure to hot surfaces or may not be aware of being burned.^5,6 The material factor involves the ability of the material to preserve high temperature after contact. Unless the material generates heat on its own, its ability to retain heat is often affected by its heat capacity and heat conductivity.

The case discussed here involved a person with paraplegia who was using a wheelchair cushion made of gel. Usually wheelchair cushions are made of plastic foam, air, or gel. Gel has a higher heat capacity and higher heat conductivity than the other materials and the fabric of the car seat.⁷ Therefore, gel wheelchair cushions may freeze in cold weather and therefore have the potential to cause skin abrasions and other skin injuries in extreme temperature conditions.⁸ Furthermore, the standard wheelchair cover is entirely black. The properties of the gel cushion and cover presented significant risks, and the burn occurred as a logical consequence.

In modern times, people with spinal cord injuries take up careers and positions in society, and their lives are not restricted to the bed and wheelchair. Accordingly, some major car manufactures sell assistive vehicles that can be controlled by hand. Additionally, there are several types of portable adaptive equipment that people can put to use and modify; even a normal rental car can be adapted to be hand-controlled by hand within a few minutes. However, cushions designed for non-wheelchair seating are generally unavailable. Therefore, it is inevitable that active wheelchair users with spinal cord injuries will use their wheelchair cushions on other seating surfaces. Consequently, similar injuries are apt to reoccur from the use of gel seat cushions in cars. Further, the risk of burns from gel wheelchair cushions is not a result of their use while driving. Rather, it is the result of leaving the cushion in a car with direct exposure to the sun similar to leaving the cushion outdoors on a sunny summer day; this could also result in exposure to extreme heat conditions, potentially resulting in burns. As a countermeasure, modifications in the design of cushion or the development of suitable alternatives for cars or outdoor use could be undertaken. Further, this type of hazard can be prevented with knowledge of the hazardous heat properties of gel cushions and the potential risk for burns. Therefore, communicating the potential hazard of gel wheelchair cushions to people with spinal cord injuries and caregivers while providing education regarding their appropriate use is of the highest priority. Education should include preventive measures such as placing white covers on gel seat cushions, placing gel cushions in the shade to avoid direct sun exposure, and touching a cushion that may have been exposed to direct sunlight to check its temperature before reusing it.

Acknowledgements

We would like to thank Yuzuru Kamei, MD, PhD and Hisakazu Kato, MD, PhD for providing valuable advice.

Disclaimer statements

Contributors None.

Funding None.

Conflicts of interest None.