File
Sabbahi W.1,2, Sabbahi M.1, Ovak-Bittar F.1
1Texas Physical Therapy and Electrophysiology services, Physical Therapy, Houston, TX, United States, 2Kowa Inc., Research, Houston, TX, United States
Background: Cryotherapy is an essential modality for rehabilitation in outpatient clinics and for sport injuries. Due to limitation on treatment time and the risk of cutaneous frost-bite, the cooling effect may reach superficial structures. Application of such modality is commonly performed by applying ice or gel packs to the treatment segment. This method applies conduction-based heat transfer. Such method uses direct contact between the heating/ cooling source and the application site. Intra-articular target tissues such as the ACL, meniscus and other structures are restricted with therapeutic treatment using conduction method (CDM). There is a need for a cooling system that can target the intra-articular structures within the allotted treatment time. Using convection heat transfer (CVM) allows heat transfer from high to low energy gradient without causing harm to the skin or subcutaneous tissue.
Purpose: The purpose of this presentation is to report on an innovative system and instrument to cool the joint/segment without direct contact. A second purpose is to compare the validity of CDM versus CVM systems in a animal pilot study.
Methods: The CVM system consists of an engine for cooling and heating air, with attachments constructed for the desired airflow pattern that circulate in a disposable cuff. The cooling system was tested on a swine cadaver leg targeting the knee joint for a period of 60 min using the following parameters, full wrap cuff with two inch inlet and outlet, 4 mil polybag 12 tall and 16.5 wide, silicone bands to hold it on, steady 35 degree F air flow, flow rate 9.6 CFM. The swine leg was tested during normal vertical position. The temperature gradient was measured for the intra articular structure progressing to subcutaneous tissues to the skin using thermocouples. Test was repeated 3 times to ensure consistency and data reliability. Test was repeated using CDM system for comparison. Results CVM shows a temperature change from 99 to 81 degrees at 20 min for the intra-articular space compared to 99 to 92 for CDM. CVM causes skin temperature changes from 95 to 69 whereas CDM showed a change from 96 to 81 degrees F. None of the cooling options dropped muscle temperature significantly.
Results: Results from the swine leg study show a temperature gradient of the intra articular structures supporting the validity of the CVM system. CVM was better cooling system than CDM. The similarity between pig and human knee structure suggest suitability of the system for application in human studies and treatment. This needs to be completed before application on patients with knee injuries. This cooling system may be applied on internal injuries for other joints in sport injuries.
Conclusion(s): A cooling system using convection heat transfer has been presented and validated in animal studies.
Implications: Human studies are required before application of the system in the clinic.
Funding acknowledgements: No funding
Topic: Electrophysical & isothermal agents
Ethics approval: Internal ethics committee Texas Electrophysiology and Physical Therapy
All authors, affiliations and abstracts have been published as submitted.
