- 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. LASER SAFETY 1. Reference: "ANSI 136.3 Publication" on laser safety 2. Four Classes of Lasers: Class I - No ocular damage with direct viewing Class II - Ocular damage with prolonged exposure Class III - Ocular damage to the eye before the eye can blink Class IV - Medical lasers. Great potential and hazard to the eye and skin. Ignites combustible materials. Beam = fire hazard. 3. Dedicated laser nurse in O.R. controlling use and monitoring laser safety 4. Key operated, controlled access. 5. Room shields to outside personnel. 6. Eye protection for patient and all OR personnel. 7. Wavelength specific eye protection hung outside the door so that people can enter the room safely. 8. Adequate smoke evacuation appropriate to tissue atomization. 9. Dual stage filtration, carbon and 0.2 um filter. 10. Coaxial visible aiming beam for use with invisible light lasers. 11. Proper filtering mask. EYE PROTECTION 1. Impact is direct or reflective. 2. Minimal hazard zone is determined to be 6 feet away from the reflected zone. 3. O.D. = Optical Density, expressed as an exponent of power of 10. i.e.: O.D. of 5 is 100 x as absorbent as O.D. of 3 4. Always expressed as an O.D. at a specific wavelength 5. Recommended to surgeon (direct viewing field) - minimum O.D. of 5 @ wavelength. 6. Recommended to OR personnel (indirect) - minimum O.D. of 3 @ wavelength. 7. Conventional glass or plastic glasses will stop CO2 8. Recommend UV coating to stop the ultraviolet fluorescence off carbonization. 9. Eye protection still necessary for endoscopic procedures, fibers could break. 10. High density filters on endoscopes, arthroscopes, waveguides. 11. The reflected light transmits directly back to the surgeon. CO2 - corneal burn. Surgeon's cornea replaceable.Argon KTP - retinal damage, Irreversible. Nd:YAG absorbed in the vitreous humor causing posterior cataract formation. Reversible? Doubtful. DRAPING FOR LASER SURGERY 1. Surgical site draping for CO2 laser use should be wet towels. 2. Drapes should be dry for the Nd:YAG procedures. (Water is a transmitter at the YAG frequency and absorbed at CO2 frequency.) 3. Laser nurse - laser on standby when not immediately using the instrument avoids accidental discharge. 4. Multiple foot switches - Bovey, power saws, table, can be confused with the laser. 5. A defocused beam has more of a tendency to start fires. 6. A focused beam will have a tendency to drill. 7. A prefocused beam will have a tendency to accelerate the hole it is drilling. The power density increases approaching the focal point. 8. Always have water on hand, to extinguish a potential flame. 9. Anodized instruments (blackened or roughened) are helpful to diffuse the beam, minimizes reflections but does not eliminate. 10. Endotracheal tubes should be coated with Mirasil (noncombustible material). HAZARDS OF THE LASER SMOKE PLUME 1. Epidermis with the CO2 laser creates a great deal of smoke. 2. The shock waves backscatter verrucoid particles which can be inhaled. 3. Vaporized tissue and debris is liberated by tissue atomization. 4. Studies show live intact DNA recovered from the laser plume. 5. Hazard in AIDS and hepatitis patients Hazard in patients with infectious lesions, i.e. warts. 6. Lesions have been reported by Dermatologists, Podiatrists, and Gynecologists. 7. Formaldehyde also produced, large number of other carcinogens. High power plume evacuators are required with dual stage filters. 1. Charcoal filter for carcinogens, smell. 2. Filtering down to 0.2 microns to filter out virus a. The key is good technique in smoke evacuation. b. Keep the smoke evacuator close to the area of surgery. c. A laser mask will filter down to 0.3 microns. d. These measures reduce nearly all of the hazards of the viral particles.