PM& R Lecture Series

1. PM& R Lecture Series Therapeutic Physical Agents

2. Physical Medicine • the application of physical agents such as: • heat • cold • sound • water • electricity and other mechanical agents in the treatment of disease.

3. Therapeutic Heat • Physiologic Effects: • Increase of 3oC increases collagenase activity • Heating hands to 450C reduces MCPJ stiffness by 20% • Changes of 5-7oC alter blood flow and collagen extensibility • Hot paraffin increases local skin temp by 7.5oC and intraarticular temp by 1.7oC

4. Therapeutic Heat

5. Therapeutic Heat Indications • relief of pain • relief of spasm • increased exetensibility of collagen tissue (e.g. fractures/contractures) • decreased joint stiffness (OA, RA) • increased blood flow * remember, the physiologic effects of heat manifest themselves only if the heat is applied for at least twenty minutes at a temperature of 40-45o C.

6. Pain Muscle spasm Contracture Tension myalgia Production of hyperemia Acceleration of metabolic process Hematoma resolution Bursitis Tenosynovitis Fibrositis Fibromyalgia Superficial thrombophlebitis Induction of reflex vasodilatation Collagen vascular disease General Indications

7. Acute inflammation, trauma or hemorrhage Bleeding disorders Cutaneous insensitivity Inability to communicate or respond to pain Poor thermal regulation Malignancy Edema Ischemia Atrophic skin Scar tissue Unstable angina or blood pressure Decompensated heart failure within 6 to 8 weeks of an MI General Contraindications

9. Hot Moist Packs • applied at a temperature of 46oC • stays warm for twenty minutes or more • inc blood flow by as much as 68% • sacks filled with silica gel (expensive) • blood flow doesn’t return to resting level until 40 mins. after cessation • for analgesia and muscle relaxation

10. Paraffin Wax Bath • applied at a temperature of 45-54oC • solution contains 1 part mineral oil (useful for those whose skin had undergone trophic changes) to 7 parts paraffin (can be tolerated by px with sensory deficits) • higher temperature is tolerable without the risk of burns (due to high specific heat of paraffin) • commonly used on the hand and wrist and other uneven surfaces

11. Paraffin Wax Bath • Dipping technique • Immerse part 6-10 times to build up layers of paraffin • Followed by wrapping extremity with an insulating cover • Skin temp achieved: 47oC • Subcutaneous temp change of 3oC • Intraarticular temp change of around 1oC • Continuous immersion • Dipped 6-10 times, then kept immersed for 20-30 mins • Subcutaneous temp change of 50C • Intraarticular temp change of 3oC

12. Infrared Radiation • Uses that portion of the EMS from 7700-150000 A • Maximum penetration of 3mm (superficial) • Dry heat (less comfortable) • Commonly used to decrease skin resistance by inc. blood flow (e.g. in Bell’s palsy) • Wound healing and other dermatological conditions (dries up wound but has no other effects unlike UV light) • Heat inversely proportional to distance and angle of delivery • Usual distance about 40-50 cm and perpendicular to surface treated

13. Hydrotherapy • applied at a temperature of 33-43oC • full body immersion can increase core temp by 0.3oC • heat and exercise can be done at the same time • bouyancy effect permits easier movement of weak or painful extremities • agitation of medium permits gentle debridement (e.g. for burns)

14. Fluidotherapy • Convection heating modality • Uses cellulose particles suspended in jets of warm air

15. Contrast Bath • One bath at 38 to 40oC • The other bath at 13 to 16oC • Produces reflex hyperemia and neurologic desentisization • Initial soaking in warm bath for 10 mins • Followed by 4 cycles of alternate 1 to 4 minute cold soaks and 4-6 minute warm soak • Ends with cold soak to minimize edema • Used in treatment of CRPS type I (RSD)

16. Ultrasound Diathermy • involves conversion of sound waves at a frequency faster than 17000-20000 cycles/sec • applied to tissues causing mechanical vibration which dissipates heat • deepest penetrating agent; only agent that can significantly heat the hip jt. (by 8-10oC) • both thermal and nonthermal effects

17. Ultrasound Diathermy • Nonthermal effects • Cavitation • US travelling through liquid produces bubbles which oscillate in size • Streaming • Produces shear forces in tissue that may accelerate metabolic processes • Standing waves • Produces areas of alternating high and low pressure

18. Ultrasound Diathermy • Penetration dependent upon: • Type of tissue • Frequency (usually 1 or 3 MHz) • Angle of orientation

19. Ultrasound Half Value Depth in Millimeters Kitchen and Bazin(1996) Clayton’s Electrotherapy 10th ed.

20. Ultrasound Diathermy • Indications • Musculoskeletal conditions (tendinitis, arthritis, patellofemoral pain) • Contractures • Wounds and inflammation • Trauma (subacute phase) • Fractures

21. Ultrasound Diathermy • Contraindications • Fluid filled cavities (eyes, gravid uterus) • Spinal cord, esp laminectomy sites • Immature bone (e.g. children) • Heart, brain, cervical ganglia • Metal implants • Methylmethacrylate implants (plastics, bone cement) • Acute inflammation

22. Injury General Musculoskeletal Disorders: Muscle spasm Joint stiffness Pain Tissue Repair: Soft tissue repair Stimulation of blood flow Bone fracture repair Tendon repair THERMAL EFFECT NON-THERMAL EFFECT CONTINUOUS WAVE PULSED WAVE

23. Shortwave diathermy • involves conversion of radiofrequency EM current into heat energy • commonly uses 27.12 Mhz • uses condenser pads, plates and internal metal electrodes for heat transfer (not very convenient) • penetration between skin and subcutaneous tissue • Can heat larger areas than ultrasound

24. Shortwave diathermy • Inductive applicators • Generate magnetic eddy currents in tissue • Highest temperature in water rich, highly conductive tissue (e.g. muscle) • Capacitively coupled applicators • Generate electrical fields • Highest temperature in water poor tissue like fat, ligament, tendon or joint capsules • May be pulsed or continuous

25. Microwave diathermy • Uses 915 and 2456 MHz • Does not penetrate as deeply as SWD or US • Highest temperatures are achieved at the fat-muscle interface

26. Therapeutic Cold • Decreases collagenase activity • Cooling hands to 180C increases MCPJ stiffness by 20% • Icing an acutely inflamed knee • Decreases skin temp by 160 C • Decreases intraarticular temp by 5-60 C

27. Therapeutic Cold * cold can also stimulate a-motor neurons and cause muscles to contract rather than relax

28. Acute musculoskeletal trauma Edema Hemorrhage Analgesia Pain Spasticity Adjunct in muscle reeducation Reduction of local and systemic metabolic activity General Indications

29. Ischemia Cold intolerance Raynaud’s phenomenon or disease Severe cold pressor responses Cold allergy Inability to communicate or respond to pain Poor thermal regulation Cutaneous insensitivity General Contraindications

30. Therapeutic Cold • Modalities • ice packs • cryogel packs • ice immersion • ice cube • ethyl chloride spray

31. Electrotherapy Transcutaneous Electrical Nerve Stimulation (TENS) • two theories: • gate control theory: • electrical stimulus carried through large a-fibers which arrive at the substantiagelatinosa before the pain impulses traveling through the c-fibers. • treatment is effective only during application. • endorphin stimulation: • TENS stimulates production of natural analgesics. • Treatment is effective even after cessation.

32. Electrotherapy • high frequency, low intensity • stimulates large diameter afferent fibers • Low frequency, high intensity • endorphin stimulation

33. Other Modalities • Low power laser • Not a heating modality • Stimulates collagen production, alters DNA synthesis, improves function of damaged nerves • FDA approved for CTS, neck, and shoulder pain

34. Other Modalities • UV light • no heating function • uses part of EMS between 1800-2900 angstroms • dose is determined by testing called Minimum Erythemal Dose (MED); erythema should appear w/in 30 mins- 1 hr and disappear after 24 hrs. • penetration does not exceed 0.1 mm • bactericidal (helps wound healing) • anti-rachitic (vit. D formation • Anti-psoriatic

35. Thank you!