Post-operative Lite Run Study

Background Cerebral palsy (CP) refers to a group of disorders affecting movement and is attributable to a non-progressive injury to the developing brain. CP is the most common cause of physical disability in childhood with a prevalence of 3.1 - 3.6 per 1000 births. At this prevalence, we estimate that over 300,000 children under 21 in the US have CP. Children with CP have a variety of neuro-motor impairments including muscle weakness and abnormal muscle tone that leads to progressive musculoskeletal impairments over time. These children experience discomfort and limitations in functional mobility such as walking (ambulation) that severely impact their quality of life. Surgical intervention is often used to improve ambulation quality and quantity for children with cerebral palsy anytime from childhood into adulthood. Depending on treatment goals, it is not unusual for an individual with cerebral palsy to undergo surgery involving muscles, tendons, bones or nerves of the feet, ankles, legs or hips. Two common surgical interventions for ambulatory children with cerebral palsy include single event multilevel orthopedic surgery to correct muscle lengths and bone alignment, and selective dorsal rhizotomy to decrease spasticity. Post-operative treatment course varies depending on the child's condition, pre-operative functional level, and specific surgical intervention selected to improve their particular deficiencies. Post-orthopedic surgery, children may be non-weight-bearing for 2-6 weeks. After selective dorsal rhizotomy, patients exhibit surgical site instability and significant trunk and leg weakness. They are non-weight-bearing for 2-4 weeks post-surgically, and may begin to stand and walk once cleared by the physician.

When beginning mobility training after orthopedic or selective dorsal rhizotomy surgery, children typically demonstrate significant weakness and can experience fear, pain and anxiety as they begin to move. One aspect of mobility that is a significant milestone for children post-surgically is getting back up and walking. The process to get back up and walk is facilitated by physical therapists and is termed "gait training" which includes the components of moving from sit to stand, bearing weight through the lower limbs, taking steps, and returning to a sitting position. Body weight-supported gait training is often used in therapy for adults and children to ease the transition from non-weight-bearing back to being able to walk at their previous level of gait function. Support during this transition may be provided by a physical therapist using a gait belt, a harness system attached to an overhead track or device to support body weight, or other assistive devices. Current body weight support systems for gait training are not optimal. Also there are reports in the literature of difficulties with harness discomfort and donning and doffing. An unpublished survey of twelve physical therapists was conducted by a University of Minnesota PT student who was able to identify 20 deficiencies in available devices for body weight supported gait training. More than 50% of the therapists cited the following sub-optimal aspects from their experiences:

• Therapist providing majority of the body weight support when using a gait belt takes away from therapeutic touch for gait therapy
• Current harness devices cannot adjust the percent of how much support the device gives
• There is not sufficient therapeutic evidence for the efficacy of current body weight support devices
• Current harness devices do not feel like they will help us prevent injury.
• Current body weight support devices only work in limited applications

Using physical therapist support for gait training without a body weight support device can require multiple people to assist, result in fatigue, and has the potential of injury for the therapist. In a survey of physical therapists working in rehabilitation facilities, 67% reported musculoskeletal pain or discomfort within the past year. Half reported that patient repositioning (49%) and gait training (47%) also caused or contributed to their pain. Another study reports survey results of over 1,000 occupational and physical therapists. The survey indicated that functional activities such as gait training and settings such as pediatric rehabilitation were associated with injury. An ergonomic analysis of physical therapists working in rehabilitation concluded that physical therapists are at high risk for work related musculoskeletal injuries while performing sit-to-stand transfers and overground gait training.

To improve gait training therapy for both therapist and patient and to reduce a therapist's need to lift and support the body weight of a patient, Lite Run Inc. has developed the Lite Run Gait Trainer (Lite Run). Lite Run is a new system for the treatment of patients with gait and balance difficulties that uses differential air pressure inside a specially designed lower body suit to effectively reduce up to 50 percent of a patient's body weight. The suit is similar to a pair of pants in appearance and is as easy to don and doff as a pair of pants. The suit uses technology like astronaut spacesuits to achieve comfort and flexibility while providing a unique "unweighting" effect that facilitates patient ambulation from sitting through taking steps. The suit is used in conjunction with the Lite Run Gait Trainer, which provides air pressure to the suit and support for the patient.

Lite Run features include: (1) control for the amount of body weight support (up to 50% of the patient's weight), (2) electro-mechanical and pneumatic controls for providing assistance in transferring the patient from sitting to standing and ambulation, (3) an open design that permits access to a patient's body and legs by the therapist, (4) a compact profile that provides easy maneuverability, and (5) a "base spread" function that permits positioning close to a patient when seated in a wheelchair, bed or therapy table.

Together, these features provide safety and stability for the patient and reduced physical burden on the therapist while improving the gait training experience and potentially preventing patient or therapist injury. The system also frees the therapist to focus on skilled therapeutic activities because the patient is secure in the system.

Lite Run conducted a product demonstration and pediatric needs survey for six physical therapists at Gillette Children's Specialty Healthcare. Current support devices used for training include overhead harness supports, robotic systems, and harness gait trainers. Therapists indicated that current devices can be uncomfortable, cause patients to "hang" on the support, and limit natural motion during sit-to-stand and walking. Gait trainers and walking devices provide trunk and pelvic support using a seat or harness, and are used with a treadmill which can be both uncomfortable and scary for children right out of surgery.

Lite Run may have FDA listing as a Class I device by mid 2017 based on adult clinical feasibility testing, and completion of independent agency testing and in-house evaluations. A clinical safety and feasibility trial for adult patients was performed at the Rehabilitation Center at North Memorial Medical Center, Robbinsdale, MN with 18 adults with a range of neurological conditions.

Adult physical therapists participating in this trial have indicated the following:

• Lite Run is comfortable. Harnesses at the groin are uncomfortable for many patients. Lite Run has the potential to decrease pain, and improve security, support, compression, adjustability, and flexibility in combination with support. It provides improved mobility during sit-to-stand. The device may allow the patient to get back up walking sooner after surgery than if they were using another device.
• It is easy for therapists to use. Pants donning time is less than 5 minutes, and requires two quick attach points to engage the patient into the device. It is easily adjustable.
• It decreases the burden on the therapist. Because the device supports the patient's body weight, therapists hands are free to provide cuing and facilitation rather than physical support. It could prevent therapist injury particularly to the back. It is fall proof.
• The device is able to quantify the amount of support provided.

The results of this study indicated that there were no adverse events or safety issues from using the system on adults. In addition to safety and feasibility testing, the following user design requirements were tested: time to don liner and pants, transfer-in time, therapist's access to patient, patient's arm mobility, hindrance of patient's stride, patient directed steerability, brake stability, overall stability, sit-to-stand functionality, wheelchair compatibility, sit-to-stand sufficiency, odometer acceptability, ease of use, and the physical effort required by the PT. After training, all therapists were all able to operate the Lite Run safely and independently. The device allowed them to use their hands to provide skilled therapeutic maneuvers, as the device provided stability and patient unweighting. The study demonstrated that the Lite Run is a safe system and shows potential for pediatric application to improve the rehabilitation experience and outcomes. Therefore, continued investigation regarding the feasibility of using the device in a post-operative pediatric population using pediatric sized lower body pressure suits is warranted.