- 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 KTP LASER APPLICATION TO HEEL SPUR SURGERY Presented in Two Sections SECTION II: APPLICATIONS OF KTP LASER TO HEEL SPUR AND PODIATRIC SURGERY At our Laser Center in Roanoke, Virginia, applications of the KTP laser are directed to cutaneous vascular diseases, spinal discectomy, and pediatric cranial neurosurgery. Its introduction into Podiatry is new. The medical-legal implications of and laser use in surgery require specifying on the consent form that the laser is applied for the soft tissue component of the surgery and requires the type of laser be specified. Also by convention, the medical and scientific community expects handling of the laser described on the operative report be expressed in terms of power density levels. This is for reproducability should other physicians wish to utilize this modality. ANATOMY AND PREPARATION OF THE FIBER: Enclosing the quartz fiber is enclosed in a plastic lining. Upon initial use of the fiber the distal end is cleaved under sterile conditions with a cutting instrument designed to penetrate only the plastic fiber cover and the quartz cortex. This is then snapped apart by hand which is termed cleaving. Recleaving of the distal end of the fiber is performed just previous to each surgical session. A clean perpendicular end with no abberations will produce an homogenous spread of radiation diverging at an angle of 15 degrees. The plastic covering of the fiber is then desheathed with a calibrated instrument removing 4.0 mm from the end. The author prefers a desheathing of 2.5 mm. for heel spur procedures. This exposed fiber area is shorter than usual to aid in dissecting through the dense striated vertical septae encountered around the calcaneous during the dissection. Desheathing any less than this distance will result in melting of the laminate. The majority of the energy will eminate from the portion of the fiber which is in contact with the tissue, usless the tissue is irradiated from the distal end. The side portion of the tip, used for dissecting, is that portion which has been roughened during desheathing. Thus this is somewhat similar to the N;dYAG contact-tip. This side portion is used to cut through the majority of tissue except for the initial incision, for which the end is used. The unusual phenomenon of this laser is that the fiver does not generate heat usless in contact with tissue. THE PROCEDURE: The surgical site is prepped and draped in the usual sterile manner with conventional anesthetic techniques applied. All betadine and surgical topical anesthetics have absorption in the visible spectra are removed with saline. Cleavage and desheathing of the fibers are performed. The author uses a continuous wave power setting at 6 watts with a 600 nm fiber desheathed at 2.5 mm. Minimal smoke evacuation is required and an operating room wall vacuum is sufficient. Power Density (P.D.) calculations are derived by dividing laser watt output by the total irradiated area of square centimeter of tissue upon which the laser beam is focused. The total tissue irradiation may be specified in joules and is described as the P.D. multiplied by the duration of time the laser transmits power. The initial incision is performed either with the KTP laser with the very end of the fiber or by conventional scalpel dissection. Unlike the Nd:YAG contact-tip, the author has not found significant thermal epidermal delamination and subsequent thermal wound dehiscence effects. This wavelength is photoablative rather than thermally ablative therefore encounters of thermal delamination of the epidermis from the dermis is not seen. The photoablative effects of the visible light KTP laser mean that decreased power density levels are required for the same degree of cutting. Also, when compared with other surgical lasers, tissue carbonization is reduced so adjacent layers are unaffected. Tissue dissection responds from laser light intensity, compared with customary mechanical scalpel pressure. The tactile feedback the KTP laser gives is somewhat reduced, and requires a short adjustment period by the surgeon. On the skin, several passes of quick smooth strokes are taken. Dissection is then continued directly through the superficial and subdermal capillary plexus. Dissection through this area is rapid to avoid excessive laser absorption at this spectra. The KTP laser expedites dissection through the pericalcaneal fat, but blunt dissection may be supplemanted. When striations of fibrous septae are encountered the most effective method to ablate them is by taking several short passes with the laser at a time. Dissection rapidly reaches the junctin of the abductor hallucis and plantar fascia, and a linear incision delineates the two. Dissection is then brought proximally to the spur area. No contact with the calcaneous is made. The transmission of this frequency is extensive through cancellous bone. The likelihood of vascular stenosis of any cancellous bone is also high, especially with the calcaneous having thin cortical margins. Dissection laterally isolates the plantar fascia from the intrinsic musculature. Excellent hemostasis of muscle tissue should be appreciated regardless of tourniquet use. The plantar exostosis may be adequately exposed now or more fully exposed with blunt dissection using an elevator. Should a fascioctomy or fasciectomy be desired the plantar fascia may be dissected using the KTP laser at this time. Short cutting strokes should be applied because the avascularity of fascia results in an increased mechanical pressure and cutting time. The calcaneal spur is removed with conventional instrumentation and irrigation and closure performed routinely. SUMMARY: The author has found that his patients with KTP laser (n > 25) sustain a clinically improved outcome over the Nd:YAG laser (n = 50). The thermal lasers still produce substantial clinical improvements over conventional cold steel dissection for heel spur procedures. These parameters have been previously quantitated and published, covering earlier painless ambulation, decreased pain measured as post-operative narcotics consumed, decreased incidence of wound dehiscence from the decreased thermal ablative effects, and decreased disability time. The KTP laser is user friendly. Nevertheless, wavelength specific training with inanimate and animate tissue is recommended to familiarize surgeons with ideosyncracies of this laser and its tissue interactions at this light spectra. The author concludes that the improved post-operative clinical outcome and subsequent decreased physician utilization justifies the utilization of the instrument.