Date on Master's Thesis/Doctoral Dissertation

5-2013

Document Type

Master's Thesis

Degree Name

M. Eng.

Department

Bioengineering

Committee Chair

Sethu, Palaniappan

Author's Keywords

Spinal cord injury; Torque; Stretching; Rat

Subject

Spinal cord--Wounds and injuries; Stretch (Physiology)

Abstract

An increasing amount of healthcare resources is used for the treatment and prevention of contractures in patients with spinal cord injury (SCI), with stretch and passive movements remaining the most prominent intervention methods. The results of both clinical trials and animal studies in recent years have shown traditional stretch therapies to be ineffective at preventing contracture and joint immobility, and have encouraged further emphasis on evidence-based practices. However, these studies only analyzed one aspect of stretching, dosage, and failed to look at the characteristic of joint torque. Recent clinical trials have unearthed the fact that the joint torque application of therapeutic stretches in the clinic not only vary by therapist, but also can be well beyond the range of torques tolerated by able-bodied individuals. A glove device utilizing force sensing resistors (FSRs) was developed to gauge joint torques. Coupled with a custom National Instruments’ LabVIEW program, the device was able to accurately measure forces, and eventually torques, applied during stretching. This study sought to explain what range of torques were being applied during stretching after SCI in the rat model in the hopes of understanding how to administer safe, effective therapeutic stretches. Six adult female Sprague-Dawley rats were mildly contused at T9 using the NYU impactor device with a 12.5 g-cm weight drop. n=2 rats were stretched 2 days per week and n=2 rats were stretched once per week using an eight minute protocol, for the first 5 weeks post-injury while controls (n=2) received no stretch therapy. Briefly, the tibialis anterior (TA) and triceps surae (TS) muscle groups were stretched by two therapists bilaterally for a minute each, totaling 4 minutes of stretch per rat per day. Kinematic assessments of stretching were accompanied by force measurement data and were used to generate comparisons between therapeutic torque and end range of motion (ROM) of the ankle. The data suggests that both once and twice per week stretching regimens were not enough to inhibit locomotor recovery or elicit a noticeable change in end ROM in such a mild injury model. There were noticeable differences in torques applied during stretching by different therapists, confirming the findings of previous studies. More importantly, the data showed that immediately after injury the normal end ROM can be achieved by applying less torque. The torque necessary to reach the end ROM increases to baseline values by week 5, potentially due to a return of the stretch reflex during spinal shock. This study urges other aspects of stretching therapy to be considered and suggests a tool for therapists to quantitatively apply safe and consistent stretching therapies to patients.

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