- 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 CO2 LASER PROPERTIES OF THE CO2 LASER 1. Active media is CO2, helium, nitrogen Carbon dioxide is the excited media Helium and neon are catalysts 2. High absorption in water, Tissue mostly water therefore superficial absorption "What-you-see-is-what-you-get" Low scattering in tissues 3. Invisible beam at 10,600 nm far-infrared, helium-neon aiming beam necessary ADVANTAGES OF USING THE CO2 LASER 1. Thermal precision Maximum impact on target and minimum damage to adjacent tissue. 2. Absolute hemostasis minimizing postoperative edema. Coagulates small blood vessels, lymphatics (<0.5 mm diameter). Minimizes pathways spreading malignant cells. 3. Accelerated healing of internal tissue because of lack of mechanical trauma. Fibroblasts are less stimulated, therefore skin sutures need to be left in tissue a few days longer, however internal scarring is less. Tissue remodeling is minimized due to little scar formation. Earlier joint range of motion. 4. Minimal postoperative pain Sealing axonal tubules in small cutaneous nerves 5. Pain may increase several days postoperatively if patient weightbearing Sealed exoplasm from nerve endings is under increased hydrostatic pressure. electrolytes stimulate neural discharge 6. Sterilization of the target site Inactivate any bacteria, fungi, or virus 7. No foreign body reaction 8. Versatile - Operates in CW or pulse mode to vaporize or incise tissue 9. Portable and inexpensive relative to other lasers 10. Minimal amount and cost of disposable laser items per case. 11. Handpieces easily sterilizable 12. Least expensive laser SELECTION OF LASER PARAMETERS 1. Appropriate power, spot size, power duration, and angle to tissue 2. Ablational work: spot size less than 2-3 mm in diameter 3. Incisional work: spot size less than 0.3 mm in diameter DISADVANTAGES 1. Cost, power, alignment, control, additional informed consent 2. Smoke evacuation system 3. Combustible materials risk, extra drapes, higher protection 4. Special training for physician/staff 5. Learning curve 6. Credentialing process/extension of privileges if hospital use PROCEDURES PERFORMED USING THE CO2 LASER ASSIST 1. Plantar Verruca Ablation 2. Porokeratoma Ablation 3. Nail Matrixectomy Ablation 4. Fungal Nail Treatment - Drilling through nail plate 5. Heel Fissure Debridement 6. Ulcer Debridement/Sterilization 7. Incisional Procedures for soft tissue component (of neuroma, bunion, etc.) THEORY OF CO2 LASER TISSUE INTERACTION 1. Controlled, highly localized vaporization. 2. Energy is absorbed by water. 3. High conductivity minimal to adjacent tissue damage. 4. Avoid tissue carbonization - increases and conducts thermal effects Immediately seen. Worse problem at low power densities. Global tissue temperature and thermal conductivity. Wipe this off with a damp gauze. CO2 LASER PROCEDURES TECHNIQUE OF CO2 LASER ABLATION 1. Power Density over 1000 W/cm2 2. Larger spot size- 2-3 mm The following diagrams, illustrate two methods: linear and circular overlap. The goal is an evenly ablated surface. 1. Circumscribe lesion by 2 mm peripherally 2. Curette representative area and send biopsy for pathology. 3. Deep channels should be avoided. 4. Do not penetrate dermis in verrucoid lesions. 5. If you have a 0.2 mm spot size at focal point, defocus to 1.0 mm. For example, 20 watts with a 1 mm spot size equals 2540 watts/cm2 power density. Scarring results from dermal penetration IPK's and porokeratosis are focally penetrated to the dermis. 1. Need to lase to subdermal fat. 2. 75% cure rate, somewhat higher than conventional applications. 3. Little scarring. 4. More focal treatment is required at higher power levels. 5. Remove char by lavage or sponge. LINEAR METHOD CIRCULAR METHOD TECHNIQUE OF CO2 LASER FOR INCISION/EXCISION 1. Power density greater than 6,000 watts/cm2 preferred 2. Small spot size, maximum 0.3 mm diameter, 3. TEM01 lasers are not able to produce less than 0.3 mm spot at focal point. Thus they are not appropriate for making incisions. 4. TEM00 lasers are available to deliver 0.1 mm, but commonly 0.2 mm. Example: a. 20 watts with 0.2 mm spot size equals 63,500 watts/cm2 power density. b. Technique: smooth rapid continuous motion. c. In focus. d. Traction and countertraction perpendicular to incision. 5. Traction/countertraction of the incised area will enable smooth tissue plane delineation. 6. Retrace path to achieve desired depth. 7. Important: Characteristics of individual lasers vary greatly. 8. Test on a tongue blade first. Depth should be a little over halfway through with minimal charring. NOTES: 1. A TEM00 laser produces a very different effect compared to a TEM01 machine 2. A superpulsed laser has a variety of pulse settings to achieve the same P.D. 3. The ultrapulsed lasers cut faster at lower power settings. 4. These are characterized by very short duration RF pulsed power supplies Power densities are a general rule of thumb and should be adjusted to 1. each wavelength, 2. the particular instrument and 3. the type of tissue undergoing surgery. HEMOSTASIS 1. By Coagulation: Defocus to a spot size greater than twice the vessel diameter Use a Power density less than 1500 watts/cm2 Technique: defocus beam to increase spot size and direct beam at site 2. By Dessication (thermal contraction): Spot size 1 mm Power density as with coagulation Technique: direct beam to tissue immediately adjacent FOCUSED, FREE BEAM LASER APPLICATIONS 1. In Focus: Incision 2. Defocus: Debulking 3. Greatly defocused: Coagulating 4. Prefocused: Avoid altogether OVERLASING Significant problem to inexperienced user is "Overlasing" Definition: delivery of an inappropriate amount of laser energy to target tissue or to the surrounding tissues producing unintended tissue destruction. (Immediately visualized with CO2 lasers.) CAVERNOUS HEMANGIOMA 1. Considered ablative surgery requiring high power densities. 2. This is a highly vascular tumor. 3. Nd:YAG (bare fiber) is appropriate for deep penetration 4. Causes deep thermal vascular stenosis. 5. CO2 is not good for coagulation for these tumors, but it can be used. 6. KTP and Argon are more appropriate for superficial vascular lesions. KELOID AND HYPERTROPHIC SCAR 1. Excellent indication for CO2 laser excision because of lack of fibroblast stimulation. 2. Superficial epidermal incision with the CO2 laser, NOT with the steel scalpel. 3. Avoid charring, will delay healing. 4. Refer to technique for incision/excision LASER ASSISTED OSSEOUS PROCEDURES 1. Advertise as laser assisted bunionectomy. 2. Lasers used for soft tissue dissection only. 3. Not FDA approved for osseous work. 4. Used for incision, soft tissue dissection and capsular work. 5. Result is less postoperative pain, edema, and earlier range of motion. 6. Fascial layers - very little water content therefore is more transmissible at this wavelength 7. Excellent for capsular incision. Earlier ROM. Contraindicated for periosteal dissection hemostasis of ALL vessels. This seals the metaphyseal arteries and slows periosteal healing 8. Remember the delayed skin healing effect 9. Leave the sutures in a few days longer 10. Fibroblast stimulation is minimal thus scar formation is minimal 11. Better cosmetic result. BONE AND CARTILAGE 1. Accidentally hitting the bone cortex will take 16-20 weeks to heal. Solution: Debride damaged cortex immediately. Damage is usually superficial. 2. Carbonization in a joint will set up severe chronic inflammation. Solution: Lighten up on capsular dissection in this area Irrigate thoroughly postoperatively, as always 3. Excellent application for subchondrodesis procedures Instead of using K-wire to drill use CO2 at high P.D. for 0.5 seconds. Space closer together with less mechanical disturbance to cartilage LASER TREATMENT OF VERRUCA 1. CO2, Nd:YAG, Argon, KTP 532 can be used. 2. Selection or combination treatments depend upon clinical presentation. The technique is to ablate in a layering method 1. Anesthesia, avoid epinephrine. Avoid directly sublesional. 2. Drape area using moist towels or laser safe drapes. 3. Power density CO2 laser: 6,000 to 21,000 watts/cm2. Decrease for light skinned and thin skinned individuals Also reduce power density for thin areas on dorsal areas of the foot 4. Circumscribe lesion taking 2 mm min border of normal appearing tissue at the periphery. Viable verruca in this tissue. 5. Do this in focus. 6. Submit representative biopsies. 7. Plow multiple interspersing furrows and crosshatch these to an even base. 8. Next wipe area with a sterile, moist gauze to remove char. Avoid relasing char. 9. Repeat lasing and wiping until dermal/epidermal separation occurs. Epidermis will appear to peel away from the dermis. 10. Several passes are required on the plantar surface of the foot. Desired depth is papillary dermis. 11. Healing will occur from basal cells in the dermal papillae. 12. Relase superficial areas until an homogeneous depth is encountered to rete ridges. 13. Photocoagulate in a defocused mode. Coagulate the surface to a very light haze. This also sterilizes the surgical bed of viral particles. 14. Work is complete. Do not revaporize. Inspect with magnification. 15. Silvadene cream and sterile dressing for 24 hours. Avoid occlusive dressings. Extra strength Tylenol for small lesions Hydrocodone 2.5 mg i-ii Q 4 h prn for large masses 16. Expect moderate drainage for 3 days to 1 week. Wound closes completely in 1 month entirely healed. In 2 months no signs of treatment are usually visible. * Treat lesions less than 1 cm from each other as one lesion * Do not leave a bridge of healthy skin between. Handling large lesions: i.e. large, mosaic verruca. 1. Keep depth of penetration even. 2. Circumscribe and divide the lesion into quadrants. 3. Lase each quadrant individually. 4. If the patient is supine, work from posterior to the anterior If bleeding is encountered be sure it does not drain over the surgical site. 5. Be prepared with extra smoke evacuation filters. To accomplish hemostasis, if needed:: 1. reduce the power density and "brush" hemorrhagic area. 2. Power density can be reduced by backing off to a defocused mode. 3. Suction blood away first - laser does not coagulate free blood Postoperative Care: 1. Patient seen 3 days to 1 week 2. Patient allowed to clean twice daily with H2O2 and bandaid exception: large lesions require redressing until drainage decreases. 3. Normal bathing after first redressing. Accommodative pad if needed. 4. Stop dressing when drainage ceases, no dressing at night. 5. Monitor patient for at least 6 months due to the nature of HPV. 6. Success rate easily 90% after learning curve reached. Complications: 1. Infection--rare, laser sterilizes the bed. 2. Overlasing 3. Increased pain--result of overlasing. 4. Increased bleeding--result of overlasing 5. Increased scarring--result of overlasing 6. Scarring--Penetration of dermis LASER NAIL MATRIXECTOMY 1. No epinephrine 2. No tourniquet - will have good hemostasis 3. Avulse the nail, do not ablate with laser 4. Power settings: 0.2 mm spot size, 125 mm focal length lense, 10 watts CW 5. Aim at 45 degrees, under proximal nail fold for acisional technique 6. Outline matrix and circumscribe to periphery of distal phalanx condyle avoid lasing bone. 7. Lase the matrix in layers achieving a uniform layer of desiccated tissue. Debride with a dermal curette to the next layer of matrix. Stop when coming close to bone. Several passes are necessary 8. Keep site very dry and free from blood. 9. Diluted phenol may be used as an adjunct, but the laser replaces the blade. NOTES: 1. Techniques for missing part of the matrix are just as probable with laser or blade 2. Characterized as a blind procedure. 3. Burning bone may result in periostitis, very rare. 4. Recurrence after learning curve partial permanent procedure, hallux, 0.5%. 5. These are the rate of results after the learning curve reached. 6. Usually recurrence is keloid, hypertrophic scar formers, and psoriatic patients 7. Patients with high epidermal growth turnover 8. Total permanent if recurrent in these patients POSTOPERATIVE CARE 1. Leave sterile dressing on 24 h Patient to change at home Patient to clean twice daily with H2O2. No soaks. 2. Some tissue necrosis 1 week 3. Patient to keep dry for 3 days 4. Patients seen 24 hours to 3 days postop 5. Bandaid dressing 6. Normal healing 7. Discontinue dressing when drainage ceases, generally 2 weeks 8. Allow it to drain 1-3 weeks until it stops draining spontaneously. 9. Total permanent drain more on the 3 week margin, lesser digit partials for a week or so. COMPLICATIONS 1. Increased pain 2. Increased drainage 3. Delayed healing 4. Soft tissue infection 5. Thermal osteitis 6. Osteomyelitis 7. Overlasing is generally the culprit of all those complications. PREVENTION OF COMPLICATIONS 1. Use appropriate power density 2. Keep the handpiece moving or apply power with periodicity 3. Keep exposure time on a given spot to a minimum 4. Don't relase over char 5. Always know where the beam is going, especially these blind procedures FROST AND WINOGRAD TECHNIQUE 1. Do not use lasers to cut the nail- excessive heat. Use incisional power densities as described for incisional procedures 2. Laser is 90 degrees to the skin, P.D.= 40,000 W/cm2 Then decrease when performing matrixectomy 3. Incision would be the same otherwise as the Winograd please refer to that section within this review book 4. Laser incision is made straight back past the eponychium Second curvilinear incision around soft tissue pathology Remove hypertrophied nail lip and granuloma tissue. 5. Closure with 4-0 Nylon suture. 6. Tourniquet is not necessary. LASER TREATMENT OF ONYCHOMYCOSIS 1. No anesthesia required 2. Laser "mottling" techniques 3. Object is to punch holes in the top nail plate 4. This allows topical medications to penetrate a. Laser settings to just barely fire through a tongue depressor. b. These settings should be just subthreshold for patient feeling any heat c. Laser must be in a pulsed mode d. holes drilled 4-5 mm apart e. Three separate treatments 6 weeks apart. f. Topical antifungal applied BID SUBTOTAL MATRIXECTOMY 1. Anesthesia as before 2. The plate is always removed conventionally 3. Lasing is performed on the total matrix 4. however only scanned to 50% of the depth 5. The idea is to remove only part of the nail matrix to result in a thinner nail SUBUNGUAL HEMATOMA 1. No anesthesia 2. Same procedure as mottling technique 3. Slightly higher power Density may be used 4. Lase a couple of holes until the nail plate is penetrated. 5. Hematoma will isolate thermal effects. LASER TREATMENT OF GRANULOMAS These respond very well to laser treatment 1. Ablate the granuloma in a crisscross pattern, the same as verruca 2. Alternate with a moist gauze until normal tissue is encountered 3. Good hemostasis should be encountered throughout the procedure 4. No chemocautery, bovey, or hemostatic solutions are necessary 5. Once the granuloma is gone the minimal bleeding encountered stops 6. Defocus, relase, apply sterile dressing. 7. Home treatment and follow-up as with verruca. CAUTION IN REVISIONAL PROCEDURES Scar tissue, if encountered, has less water content. Therefore reduce power density when you relase this type of tissues. Otherwise excess vaporization penetrating tissue planes may occur.