- 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 ARGON LASER GENERAL DESCRIPTION 1. Dual wavelength output: Blue 488 nm Green 514 nm very close to KTP 532 nm (pure green) 2. 1 to 2 mm depth of penetration. 3. Operates as a coagulation device, not used for cutting 4. Argon and KTP pass epidermis to absorb in the dermal hemoglobin selectively Nd:YAG and CO2 do not absorb in the region of the Hb curve 5. Fiberoptic delivery system 6. Collimated handpiece, freebeam fiber, contact 7. Aiming beam is a low power argon beam, hard to see through OD 3 or 5 glasses 8. 30 degree divergence on the KTP fiber, 2 degree divergence on the Argon fiber. 9. 488 nm filter is used to filter out green component 10. Hemoglobin Absorption is a bimodal curve 11. Ideally the wavelength should fall on the peak absorption of this curve and be maximally transmissible through other tissues MECHANISM OF ACTION 1. Chromophores on the bottom of the foot are minimal 2. They pose little problem because the epidermis, dermis basal layer is transparent to this wavelength 3. Absorption at this wavelength is low first absorbed in the hemoglobin within the vessels of the reticular dermis 4. Vessels are stenosed via selective photoablation. a. Able to coagulate vessels less than 1 mm in diameter. b. Indicated for tissue coagulation and necrosis procedures (acisional) c. KTP laser, 532 nm can be used also for vascular stenosis. d. Deeper dermal structures, such as capillary hemangioma, other lasers are indicated for this such as the free beam Nd:YAG. EYE PROTECTION 1. Optical Density (O.D.) minimum of 5 at 488 nm. 2. Unfortunately, these glasses block out the aiming beam The aiming beam is a low level intensity treatment beam. 3. Visible light eye protection radically alters the colors of the surgical field SURGICAL APPLICATIONS INDICATIONS FOR THE ARGON LASER 1. This treatment is very useful for incisionless surgery It is highly favored by the patient, particularly in the large verrucae on the plantar aspect of the foot and the posterior aspect of the heel normally a CO2 laser would leave an ulcerative defect Immediate shoe gear 2. Multiple disseminating lesions or mosaic warts on the plantar foot 3. Vascular lesions of a superficial nature 4. Patients having communicable diseases when a bloodless field is desired 5. It is not indicated for highly fibrotic and scarred verrucoid lesions. Scar tissue transmits this frequency giving a painful result ADVANTAGES 1. Minimal exposure to blood--this is an incisionless procedure. 2. Decreased laser plume about 5% of that with CO2 laser A smoke evacuator is still required 3. Good treatment for immunocompromised patients 4. Faster than CO2 laser, i.e. a 45 minute procedure for the CO2 laser for verruca plantaris would take 5 minutes with the Argon laser 5. It is repeatable 6. Sterile preparation unnecessary. Surgeon still should be gloved for isolation from lesion contaminants. ARGON LASER DESTRUCTION OF VERRUCA 1. Object = delivery of energy to the superficial dermis - papillary plexus These are the vessels feeding the wart. The wart is an epidermal structure, not a dermal structure. It is however fed by vessels from the dermis. 2. Anesthesia peripheral to lesions and without epinephrine 3. Thick sections of epidermis should be debrided previous to treatment This minimizes epidermal carbonization. 4. Inject peripherally - do not blanch skin from the injection pressure 5. Collimated handpiece is used with 600 nm to 1 mm diameter fiber 6. 5 degree to 30 degree divergence. Focusing handpieces are available. 7. Bare fiber is held 1-2 cm from tissue 8. 2-4 mm spot, 5.5 watts, 0.5 seconds for the plantar foot. May be used continuous mode and brushed when a good technique is adapted.9. Selection of appropriate power density is very important. 3 watts for thin skin, 6.5 watts for thick skin 10. Include 2 - 3 mm border peripheral to the wart, 11. Carefully check this tissue for a "blanching effect". 12. Allow for a 3 to 5 second delay in this blanching 13. This is a result of the coagulation of the superficial dermal vessels. No vaporization occurs NOTES: 1. Some carbonization is normal in thick epidermis Avoid charring this by continuous circular motions. 2. When blanching occurs, this is the proper setting. Also the proper rate of handpiece movement. 3. This is a time dependent phenomena. 4. After the vasculature is coagulated the chromophores have absorbed the wavelength. 5. If blanching is not encountered, do not increase power, do not slow down handpiece movement. 6. Repeat the same movement of the handpiece over the area. 7. When proper parameters are determined, continue treatment beyond the test area. 8. The result is not only power and spot size, giving P.D., but time dependent. POSTOPERATIVE CARE 1. Accommodative pad prn No dressing necessary. Patient can put his shoe and sock on and walk out of the operating room. 2. Hydrocodone 2.5 mg i-ii Q 4-6 h prn pain 3. Blistering likely to occur in 3 to 5 days. Patient may incise and drain this at home. After I&D, patient is to leave the skin on, for a protective barrier. 4. At one week a black necrotic skin component will form This lasts 3 weeks and spontaneously sheds. 5. Check patient in 3-4. Recheck in 10 weeks. 6. Should fully heal within 4 to 5 weeks. No scarring should be seen. A slight hypopigmentation may be observed. 7. Ulceration is not possible with this laser as the chromophores, hemoglobin and oxyhemoglobin stops the absorption in the superficial papillary plexus.