- THIS MATERIAL IS PUBLISHED AND PROTECTED BY U.S. COPYRIGHT LAW - REPRODUCTION PROHIBITED UNLESS FOR PERSONAL USE, EXCEPTING AUTHOR PERMISSION - Peter F. Kelly, D.P.M., F.A.C.F.A.S. Diplomate, American Board of Podiatric Surgery Fellow, American College of Foot and Ankle Surgeons CHAPTER 37 LASER APPLICATIONS IN PODIATRIC SURGERY TABLE OF CONTENTS LASERS AND LASER PHYSICS HISTORY UNITS OF MEASUREMENT FUNDAMENTALS UNIQUE CHARACTERISTICS OF LASER LIGHT COMPONENTS OF A LASER LASER V. CONVENTIONAL PHOTONIC RADIATION THEORY of LASER OPERATION REALATION OF LASER LIGHT V. CONVENTIONAL LIGHT DELIVERY MECHANISMS TRANSMISSION MODES TISSUE INTERACTION TRANSMISSION CHARACTERISTICS THROUGH TISSUE CLINICAL TISSUE INTERACTION PHENOMENA POWER DENSITY WATTS PER CM2 Chart TIME LASERS APPLICABLE TO PODIATRIC SURGERY ----------------------------------------------------------------------------------- LASER SAFETY EYE PROTECTION HAZARDS OF THE LASER SMOKE PLUME ----------------------------------------------------------------------------------- CLINICAL LASER APPLICATIONS IN PODIATRIC SURGERY STANDARD OF CARE THE CO2 LASER PROPERTIES OF THE CO2 LASER ADVANTAGES OF USING THE CO2 LASER SELECTION OF LASER PARAMETERS DISADVANTAGES PROCEDURES PERFORMED USING THE CO2 LASER ASSIST THEORY OF CO2 LASER TISSUE INTERACTION CO2 LASER PROCEDURES TECHNIQUE OF CO2 LASER ABLATION TECHNIQUE OF CO2 LASER FOR INCISION/EXCISION HEMOSTASIS FOCUSED, FREE BEAM LASER APPLICATIONS OVERLASING CAVERNOUS HEMANGIOMA KELOID AND HYPERTROPHIC SCAR LASER ASSISTED OSSEOUS PROCEDURES BONE AND CARTILAGE LASER TREATMENT OF VERRUCA LASER NAIL MATRIXECTOMY POSTOPERATIVE CARE COMPLICATIONS PREVENTION OF COMPLICATIONS FROST AND WINOGRAD TECHNIQUE LASER TREATMENT OF ONYCHOMYCOSIS SUBTOTAL MATRIXECTOMY SUBUNGUAL HEMATOMA LASER TREATMENT OF GRANULOMAS CAUTION IN REVISIONAL PROCEDURES ----------------------------------------------------------------------------------- THE Nd:YAG LASER GENERAL DESCRIPTION MODES OF OPERATION THE CONTACT TIP SURGICAL APPLICATIONS ADVANTAGES OF Nd:YAG OVER SCALPEL Nd:YAG MEDICAL INDICATIONS PODIATRIC MEDICAL INDICATIONS FOR Nd:YAG SCALPEL CONTRAINDICATIONS INDICATIONS FOR FROSTED AND NONFROSTED CONTACT TIPS INAPPROPRIATE Nd:YAG PROCEDURES GENERAL CONSIDERATIONS IN APPLICATION OF THE Nd:YAG LASER REALISTIC EXPECTATIONS ----------------------------------------------------------------------------------- THE ARGON LASER GENERAL DESCRIPTION MECHANISM OF ACTION EYE PROTECTION SURGICAL APPLICATIONS INDICATIONS FOR THE ARGON LASER ADVANTAGES ARGON LASER DESTRUCTION OF VERRUCA POSTOPERATIVE CARE ----------------------------------------------------------------------------------- THE KTP LASER GENERAL CHARACTERISTICS FIBER PREPARATION SURGICAL APPLICATIONS KTP TREATMENT OF VERRUCA KTP APPLICATIONS TO PLANTAR FASCIOTOMY MECHANISM OF ACTION THERMAL LASER PROBLEMS INDICATING KTP LASER DISADVANTAGES OF KTP LASER ----------------------------------------------------------------------------------- OTHER SURGICAL LASERS Ho:YAG LASER COPPER VAPOR LASER Q-SWITCHED LASERS EXCIMER LASER Er:YAG LASER ----------------------------------------------------------------------------------- PHOTODYNAMIC THERAPY "PDT" MECHANISM OF OPERATION ----------------------------------------------------------------------------------- BIOSTIMULATION "BIOSTIM" ----------------------------------------------------------------------------------- BIBLIOGRAPHY SPEED-READING BIBLIOGRAPHY FURTHER READING LASER APPLICATIONS IN PODIATRIC SURGERY Applications of lasers to medicine and surgery have increased exponentially over the past decade. This technology has become established in the medical community and has become the standard of care for many procedures. Lasers have justified their utilization by the improved clinical outcome in the delivery of comparably more traumatic and invasive procedures. Some procedures are not possible without the precision or uniqueness of this modality. There are a great variety of laser types and delivery systems, each having indications unique to the desired tissue response. Fundamental to the surgeon in selecting the wavelength, power and control to produce the intended effect, with safe handling of the instrument, is a knowledge of laser physics for this tissue interaction. CLINICAL LASER APPLICATIONS IN PODIATRIC SURGERY STANDARD OF CARE 1. OPERATIVE REPORT - Include laser type power density calculation. i.e.: "Procedure: Austin Bunionectomy, left foot (Soft tissue with CO2 laser): With the CO2 laser set at 33,000 W/cm2 power density, a linear incision was ..." 2. CONSENT FORM - Include the laser type or wavelength used and the intended application of the laser if there is conventional instrumentation used. i.e.: "(Usual description of surgery), soft tissue with CO2 laser" 3. ETHICS IN ADVERTISING - Differentiate the application of the laser i.e.: "Laser assisted" bunionectomy, or "Laser for soft tissue" Advertise straightforward what laser procedures (warts, nails) are done if also advertising conventional procedures (bunionectomy) that are not performed with laser assistance. Public misconceptions: No incision, laser cuts bone. You will never lose a patient because of an honest disclosure of a procedure. THE KTP LASER GENERAL CHARACTERISTICS 1. Very similar to Argon laser. Single wavelength 532 nm (v. 514 nm Argon). 2. Difference: KTP can cut tissue, contact mode 3. Very useful in selected tissue (below) 4. A frequency doubled Nd:YAG laser 5. Blanching of the skin also seen similar to the Argon laser 6. Note indications for vascular tumors: Argon superficial KTP moderate Nd:YAG (bare fiber) deep 7. Absorption coefficient is slightly increased over the Argon A.C. - The distance it takes for the radiation to diminish 90% in tissue. 8. Contraindicated in surgery in close proximity (0.5 cm) to thin cortical bone Vessels of the bone will absorb this wavelength, necrose vascular supply 9. Contact mode and free beam mode FIBER PREPARATION Fiber preparation is done previous to each case 1. Fiber must be cleaved: a. Optical fibers have a crystalline nature b. A cleaver is used to penetrate the sheath and score the fiber cortex this sets up a stress riser so the fiber can be snapped c. the end of the fiber is inspected for a flat, even surface emitted laser light should be circular and symmetrical d. The sheath must be stripped. e. 4 mm recommended by manufacturer, but emits too much lateral light f. so strip 2-3 mm instead, but enough so the sheath doesn't melt g. So leave it to Cleaver to strip off the sheath for fiber preparation SURGICAL APPLICATIONS KTP TREATMENT OF VERRUCA 1. Same as for Argon 2. Treatment is slightly deeper 3. Blanching is similar but has more significance of penetration depth KTP APPLICATIONS TO PLANTAR FASCIOTOMY MECHANISM OF ACTION a. KTP is a nonthermal laser b. Selective wavelength absorption c. Operates in contact mode by specific photoablation of protein and hemoglobin. d. Pericalcaneal tissue = adipose, muscle, and plantar fascia Advantage - transmission through clear adipose. Advantage - plantar muscle contact - very little bleeding e. Muscle is highly vascular and plantar fascia is separated off Usually muscular bleeding is considerable Absorption in muscle is superficial - stopped by Hb f. Lower power levels required THERMAL LASER PROBLEMS INDICATING KTP LASER a. Thermal lasers, CO2, Nd:YAG --> adipose photohydrolysis and liquefaction b. This water and fat liquefaction interferes with laser cutting c. Disadvantage CO2 laser - strongly absorbed by water and no cutting occurs d. Disadvantage Nd:YAG laser - water transmits and energy is disseminated. e. Surgical site in heel spur work is deep and visibility must be optimized Particularly with endoscopic size incisions DISADVANTAGES OF KTP LASER a. Retinal hazard b. Fiber preparation before every case c. Cannot dissect in close proximity to bone d. Inefficient laser - requires dedicated 220 V 50 A line e. Larger zone of necrotic damage and zone of coagulation than the CO2 f. Takes a long time to dissect through vertical septa and plantar fascia g. Must take care not to deliver much energy into muscle (well absorbed) h. Learning curve