The KTP laser: an emerging tool in pediatric otolaryngology

PURPOSE: To report the frequency and spectrum of use of the potassium titanyl phosphate (KTP) laser in a tertiary referral pediatric otolaryngology practice and to focus on a novel use for the KTP laser which has not previously been described in the literature. DESIGN: A retrospective chart review of the operative log database of a pediatric otolaryngologist in a tertiary referral setting over a seven year period. RESULTS: Out of 2886 cases, a total of 49 (1.7%) involved the use of the KTP laser. These included 7 otologic cases, 3 laryngeal cases, 31 subglottic/tracheal cases, 1 esophageal case and 7 nasal cases. One of these cases involved a previously unreported use of the KTP laser, closure of a tracheo-esophageal fistula (TEF). CONCLUSION: The KTP laser is an important operative tool in pediatric otolaryngology and new uses for this laser continue to emerge. One of these, KTP closure of a TEF offers pediatric otolaryngologists the potential for significant changes in management of this congenital problem with reduced surgical morbidity. Familiarity with the KTP laser and expertise in its use and applications is essential in providing state-of-the-art care to pediatric otolaryngology patients in a tertiary referral center.     

Endoscopic KTP laser excision of severe tracheotomy-associated suprastomal collapse

OBJECTIVE: The purpose of this study was to investigate the feasibility, safety, and clinical utility of potassium-titanium-phosphate (KTP) laser bronchoscopy for excision of severe, obstructing tracheotomy-associated suprastomal collapse. METHODS: A retrospective review was performed of six children at a tertiary care children's hospital with severe tracheotomy-associated collapse of the suprastomal anterior tracheal wall cartilage, precluding decannulation. All subjects had undergone KTP laser endoscopic excision of the collapsed segment of suprastomal tracheal cartilage. Medical records were assessed for: (1) endoscopic demonstration of relief of suprastomal collapse, and (2) successful tracheotomy decannulation. RESULTS: All six patients had endoscopic evidence of relief of suprastomal airway obstruction after KTP laser therapy. Five of six (83%) subsequently underwent successful decannulation. There was one case of minimal thermal airway injury associated with a laser fire during use of the KTP laser, the effects of which were fortunately transient. CONCLUSIONS: KTP laser bronchoscopic excision of severe tracheotomy-associated suprastomal collapse: (1) is a feasible technique; (2) results in relief of suprastomal obstruction with subsequent successful decannulation in selected patients; and (3) avoids the need for more extensive open neck procedures. However, risks of KTP laser therapy are not negligible and strategies must be in place to minimize the occurrence of complications.     

Pulsed angiolytic laser treatment of ectasias and varices in singers

OBJECTIVES: Varices and ectasias in singers are typically the result of phonotraumatic shearing stresses and/or collision forces on the microcirculation within the superficial lamina propria. These lesions can be debilitating in performing vocalists because of the effect of recurrent hemorrhage and/or as a contributing factor to the morbidity of other mass lesions such as polyps, nodules, and cysts. Phonomicrosurgical treatment of performers is understandably approached with great trepidation, as the vocal liability of surgically disturbing the superficial lamina propria and epithelium must be balanced with the inherent detrimental vocal effect(s) of the lesion(s). Pulsed angiolytic lasers that emit radiation at high absorbance peaks of oxyhemoglobin were examined to determine whether they were an efficacious treatment approach for ectasias and varices based on these lasers' mechanisms of action and prior experience in phonomicrosurgery. METHODS: A prospective trial was done in 39 patients (40 procedures in 54 vocal folds) without complication to evaluate the effectiveness of a 585-nm pulsed dye laser (PDL; 25 cases) and a 532-nm pulsed KTP laser (15 cases) in a noncontact mode to treat 65 varices and 43 ectasias. Twenty-nine of 39 patients had varices and ectasias associated with other phonotraumatic mass lesions that required resection. Results: All patients have resumed full vocal activities, and no patient has had a subsequent hemorrhage or vocal deterioration. CONCLUSIONS: Both the 585-nm PDL and the 532-nm pulsed KTP laser were found to be efficacious and relatively safe treatment modalities for vascular abnormalities of the vocal folds in singers. Noncontact selective photoangiolysis of the aberrant vessels prevented future bleeding without substantial photothermal trauma to the overlying epithelium and surrounding delicate superficial lamina propria, thereby allowing for optimal postoperative mucosal pliability and glottal sound production. However, the pulsed KTP laser was substantially easier to use because of its enhanced hemostasis due to its longer pulse width. Vessel wall rupture was commonplace during use of the 585-nm PDL, but rarely occurred during photoangiolysis with the 532-nm pulsed KTP laser.     

Photocoagulation of microvascular and hemorrhagic lesions of the vocal fold with the KTP laser

OBJECTIVES: Ectasias and varices of the vocal fold are microvascular lesions that are often due to chronic abuse of the voice, and are occasionally encountered in association with other disorders such as polyps, Reinke's edema, and hematoma. The KTP laser can be used for photocoagulation of small vascular lesions, because the laser beam is well absorbed by hemoglobin, and damage to the epithelium is minimal. The present pilot study examined how the KTP laser could be used for microvascular lesions and their associated lesions. METHODS: Twelve patients who had undergone phonomicrosurgery were enrolled in the present study. The microvascular lesions were treated by photocoagulation with the laser set at a low power of 1.5 W in the continuous mode, while preserving the epithelium, and associated lesions were then treated by microdissection with cold instruments. The postoperative phonatory function was assessed by maximum phonation time, a perceptual test rating (GRBAS scale), and stroboscopy. RESULTS: The procedures were completed successfully in all cases. An exceptional case of a small hemorrhagic polyp allowed treatment with the laser only. The postoperative stroboscopic findings, maximum phonation time, and perceptual test rating all showed significant improvement compared with the preoperative state. No adverse effects, such as scarring or reduction of the mucosal wave, were observed in the current series. CONCLUSIONS: KTP laser photocoagulation is a relatively simple and safe procedure for treating microvascular lesions of the vocal fold. It is not recommended for photocoagulation of hemorrhagic polyps or hematomas, because such lesions have little blood flow inside and thus photocoagulation is usually impossible or requires too much laser energy. However, photocoagulation of perimeter or feeding vessels of such disorders may facilitate the following procedure by avoiding unnecessary bleeding, as well as preventing recurrence of hemorrhagic lesions.     

Clearing microvascular lesions of the true vocal fold with the KTP/532 laser

Although used for treating vascular malformations, KTP (532 nm) lasers have not been used to treat microvascular lesions of the vocal fold. The efficiency of KTP laser operation in the continuous mode with a 0.4- or 0.6-mm beam (1- to 2-W aim for 3 to 7 seconds delivering a total energy of 3 to 7 J) was studied retrospectively in patients with microvascular lesions of the vocal fold (n = 14). The perceptual acoustic, phonatory function, and videolaryngostroboscopic data were evaluated before and after operation in 10 patients. At follow-up (mean, 7 months), the results were excellent in all patients. Their phonatory function (jitter, shimmer, grade, breathiness, and roughness) significantly improved (p < .01). The videolaryngostroboscopic rating showed significant improvement in the amplitude of vocal fold vibration and excursion of the mucosal wave (p < .05). No postoperative recurrence or complications were noted. The KTP laser operation is a useful, cost-effective, and time-saving procedure and can be considered as an option in management of patients with microvascular lesions of the vocal fold, particularly those with repeated hemorrhages. Because the operation is easy (compared to other surgical methods) and has no major side effects, the prospect of total patient recovery is excellent.     

Pediatric postcricoid vascular malformation: a diagnostic and treatment challenge

Hemangioma of the upper aerodigestive tract is a rarely reported occurrence in the pediatric literature. To date, there have been three published case reports of postcricoid hemangiomas contributing to unexplained dysphagia and respiratory distress. We present three children with a history of swallowing difficulty and stridor who were found to have an occult postcricoid mass. Valsalva maneuvers confirmed the suspicion of a vascular malformation in both patients. Transoral laser therapy (KTP and CO2) was used to ablate the lesions. The patients are symptom-free at 5 months, 5 years, and 2 weeks, respectively. The diagnostic challenge in evaluating these children and the therapeutic choices are described.     

Laser division of congenital complete tracheal rings

Congenital complete tracheal rings are a rare and life threatening problem in young children and they are often challenging to manage. Whilst historically associated with high mortality rates increasing experience with this tracheal pathology has led to much improved survival rates and slide tracheoplasty has become the treatment of choice. We present 3 cases in which an open procedure was not deemed possible and they underwent laser division (CO2, KTP) of their complete rings. Two patients subsequently required stent insertion. All patients are alive and well at a mean follow up of 3 years and 5 months. Whilst laser division of complete tracheal rings has only been described in a small number of cases it may provide an alternative approach in patients who are not able to undergo an open procedure or in an emergency situation.     

Use of potassium titanyl phosphate (KTP) laser in management of subglottic hemangiomas

OBJECTIVE: to study the role of KTP laser in management of subglottic hemangioma. DESIGN: retrospective analysis of patients with subglottic hemangioma treated by the senior authors. Setting: tertiary care teaching hospital. PATIENTS: twelve patients with subglottic hemangiomas. INTERVENTION: patients were treated with KTP laser (eight cases), CO(2) laser (two cases) or observation (two cases). MAIN OUTCOME MEASURE: resolution of symptoms, decrease in size of subglottic hemangioma or tracheotomy decannulation. RESULTS: All patients treated with KTP laser or CO(2) laser had resolution of symptoms and five tracheotomy-dependent children were decannulated. CONCLUSION: subglottic hemangioma is a potentially life-threatening disease seen in young children. Most authors recommend use of either CO(2) or open surgical excision. There is very little data available on the use of KTP lasers in the management of subglottic hemangiomas. The KTP laser beam is preferentially absorbed by hemoglobin making this laser system more applicable to the treatment of vascular tumors such as the hemangioma. KTP laser is a good tool for management of subglottic hemangioma with a low incidence of complications.     

Tracheal granulation tissue after percutaneous tracheostomy treated with Nd:Yag laser: three cases

Three adult patients who received percutaneous serial dilatational tracheostomy post-cardiac surgery developed histologically confirmed tracheal granulation tissue superior to the point of entry of the tracheostomy tube into the trachea. This tissue significantly occluded the trachea in all patients and, in two, led to serious haemorrhage. Each patient had serial dilatational percutaneous tracheostomy using the Cook/Ciaglia technique. On each patient fibre-optic bronchoscopy confirmed satisfactory position of the guidewire and tracheostomy tube. Nd:Yag laser therapy was applied to areas of tracheal granulation tissue and was also employed to secure haemostasis. In each patient endobronchial Nd:YAG laser therapy successfully cleared the granulation tissue and secured haemostasis. Follow-up bronchoscopy showed no recurrence. Fibre-optic bronchoscopy at the time of tracheal decannulation may identify granulation tissue requiring appropriate referral and intervention.     

Applications of the KTP laser in chronic ear surgery

Several types of lasers have been applied to otologic surgery for such procedures as laser stapedotomy and acoustic tumor vaporization. The KTP laser has even broader applications in the field of chronic ear surgery. A three and a half year experience with the KTP laser is described. This laser's performance characteristics makes it well suited for chronic ear surgery. A quartz fiber delivery device enables the surgeon hand control of the laser beam in a microscopic field. Several applications are reviewed. Specifically, the KTP laser has been effective in removing hyperplastic infected mucosa engulfing the stapes, in safely disarticulating a mobile stapes suprastructure for complete cholesteatoma removal, and in atraumatically removing previously inserted ossicles or other middle ear implants. The KTP laser enables the surgeon to avoid mechanical trauma possible with traditional instrumentation and obtain more effective disease removal.     

Management of tracheal lesions in Hurler syndrome

Hurler syndrome is a rare mucopolysaccharide storage disease that becomes clinically apparent during early childhood as mucopolysaccharide deposits form in skeletal and soft tissues. Progressive mucopolysaccharide deposition in the oropharynx and tracheal connective tissues leads to airway obstruction if untreated. Tonsillectomy, adenoidectomy, and tracheostomy have been utilized to provide symptomatic relief of upper airway obstruction. Treatment of tracheal lesions by laser excision is a recent innovative method for the management of airway obstruction in children with Hurler syndrome. We describe two boys with Hurler syndrome whose mucopolysaccharide tracheal lesions were excised by utilization of the carbon dioxide laser.     

A new technique for the management of inaccessible anterior glottic lesions

We describe a new technique for removing anterior vocal fold lesions, which cannot be visualized with conventional suspension laryngoscopy. These situations are rare and the only alternative surgeons have had previously is an open laryngeal procedure. The technique we describe involves the use of a laryngeal mask airway (LMA), a flexible bronchoscope with biopsy channel, a 400 microm laser fibre and KTP/532 nm laser. This method was used to treat two patients in whom conventional suspension laryngoscopy had previously been attempted and abandoned.     

Morbidity in pediatric tonsillectomy

Tonsillectomy is one of the most common operations performed in the pediatric age group. Previous literature on morbidity in tonsillectomy has dealt predominantly with postoperative hemorrhage. Children undergoing tonsillectomy were divided in a prospective and random fashion into eight study groups to evaluate postoperative morbidity as it relates to the surgical technique used (electrocautery, dissection, KTP laser), methods of hemostasis (electrocautery, suture ligature), and the use of postoperative antibiotics. A total of 80 children were evaluated. Using the parameters of morbidity as defined in this study, blunt dissection tonsillectomy using suture ligatures for hemostasis, without postoperative antibiotics was found to result in the least morbidity in the pediatric age group.     

Oncocytic variant of a ductal retention cyst in the interarytenoid region

Laryngeal cysts are a mixed group of benign lesions that have been classified as per their site of origin and histopathology. We report a case of an interarytenoid cyst in a 56 year old male with hyperparathyroidism. The cyst was resected under an operating microscope using KTP532 laser. It was reported on histopathology as an oncocytic variant of a ductal retention cyst.     

Effects of Scalpel,Electrocautery, and CO2 and KTP Lasers on Wound Healing in Rat Tongues

Objective: Evaluate wound healing of incisions created by the scalpel, electrocautery, CO2 laser, and potassium titanyl phosphate (KTP) laser in the upper aerodigestive tract in an animal model. Study Design: Prospective randomized study in an animal model. Methods: Postoperative oral intake, histologic depth of injury, and tensile mechanical strength were measured in rat tongues after creating incisions using a scalpel, electrocautery, CO2 laser, and KTP laser. An unpaired, two-tailed Student's t-test was used to compare results between the experimental groups. Results: Oral intake, indirectly assessed by postoperative weight loss, by the third postoperative day was significantly decreased in the electrocautery (P = 0.004), CO2 laser (P = 0.001), and KTP laser (P = 0.0001) groups as compared with the scalpel group. The depth of the wound healing, as assessed by histologic examination, was successively greater for the scalpel (75 ± 13 μm), electrocautery (110 ± 10 μm), CO2 laser (145 ± 10 μm), and KTP laser (195 ± 23 μm) groups. However, this difference was only statistically significant for the CO2 laser (P = 0.006) and KTP laser (P = 0.01) groups relative to the scalpel group. Wounds created by the KTP laser had the lowest strength (76.5 ± 6.9 kPa) as compared with the CO2 laser (156 ± 28.4 kPa), electrocautery (153 ± 15.7 kPa), and scalpel groups (249 ± 61.8 kPa). This difference was only statistically significant for the KTP laser group (P = 0.02) when compared with the scalpel group. Conclusions: Wounds created in the upper aerodigestive tract of rats by scalpels result in the least postoperative weight loss, tissue destruction, and decrease in tensile strength, whereas wounds created by the KTP laser demonstrated a significantly greater postoperative weight loss, depth of wounding, and decrease in tensile strength.     

Effects of 532 nm pulsed-KTP laser parameters on vessel ablation in the avian chorioallantoic membrane: implications for vocal fold mucosa

OBJECTIVES: Selective vascular ablation (photoangiolysis) using pulsed lasers that target hemoglobin is an effective treatment strategy for many vocal fold lesions. However, vessel rupture with extravasation of blood reduces selectivity for vessels, which is frequently observed with the 0.45-ms, 585-nm pulsed dye laser. Previous studies have shown that vessel rupture is the result of vaporization of blood, an event that varies with laser pulse width and pulse fluence (energy per unit area). Clinical observations using a 532-nm wavelength pulsed potassium-titanyl-phosphate (KTP) laser revealed less laser-induced hemorrhage than the pulsed dye laser. This study investigated settings for the pulsed KTP laser to achieve selective vessel destruction without rupture using the avian chorioallantoic membrane under conditions similar to flexible laryngoscopic delivery of the laser in clinical practice. STUDY DESIGN: The chick chorioallantoic membrane offers convenient access to many small blood vessels similar in size to those targeted in human vocal fold. Using a 532-nm pulsed KTP laser, pulse width, pulse energy, and working distance from the optical delivery fiber were varied to assess influence on the ability to achieve vessel coagulation without vessel wall rupture. METHODS: Third-order vessels (n = 135) were irradiated: Energy (471-550 mJ), pulse width (10, 15, 30 ms), and fiber-to-tissue distance (1 mm, 3 mm) were varied systematically. RESULTS: Selective vessel destruction without vessel wall rupture was more often achieved by increasing pulse width, increasing the fiber-to-tissue distance, and decreasing energy. Vessel destruction without rupture was consistently achieved using 15- or 30-ms pulses with a fiber-to-tissue distance of 3 mm (pulse fluence of 13-16 J/cm). CONCLUSIONS: This study substantiates our clinical observation that a 532-nm pulsed KTP laser was effective for ablating microcirculation while minimizing vessel wall rupture and hemorrhage.     

Effect of KTP laser on implants used in middle-ear surgery

The present study is intended to explore the effects of the KTP laser on various types of implant, used in middle-ear surgery. A laboratory study was undertaken to evaluate the interaction between the KTP laser (KTP-532 Orion Laser, Laserscope, UK) and individual middle-ear implants. A variety of middle-ear implants were used: a silicone sheet, Teflon, hydroxylapatite, ionomeric cement, gold and titanium prostheses as well as gelfoam. Following exposure to the laser, these implants were studied by direct inspection using an operating microscope. The KTP laser induced no detectable alteration in any of the implants when they were clean and dry. However, in the presence of fresh blood, under the influence of the energy of the absorbed laser, the silicone burnt and melted and the Teflon piston was vaporized. Likewise, a few tiny holes appeared on the surface of the ionomeric implant and then the prosthesis deformed. The hydroxylapatite implant broke into two pieces. However, no detectable alteration could be observed on gold or titanium pistons, even in the presence of blood. The authors conclude, that in the presence of blood, interaction between the KTP laser and both silicone and hydroxylapatite implants needs to be avoided. Teflon prostheses can be cautiously vaporized. Gold and titanium prostheses were unaffected by laser even in the presence of blood.     

Isolated endobronchial atypical mycobacterium in a child: a case report and review of the literature

Isolated endobronchial lesions caused by Mycobacterium avium are rare, especially in the pediatric population. We share the case of a 10-month-old boy who, after 1 week of cough and low-grade fever, had a radiographic examination showing endobronchial obstruction. At bronchoscopy, a granuloma of the left bronchus intermedius was found. Histopathologic examination revealed necrotizing granulomatous inflammation. Kinyoun Acid Fast stain revealed acid fast bacilli. Cultures were positive for M. avium. Current treatment options and controversies are presented. The roles of antibiotics and steroids in preventing progressive disease are discussed. The need for serial bronchoscopy and the potential benefits of surgical resection are discussed. Isolated endobronchial M. avium infection remains a rare and challenging problem. The paucity of clinical experience, and variation in patient presentation, obligates a high index of suspicion, and frequent follow-up with bronchoscopic examination and pulmonary assessment, for the child diagnosed with isolated endobronchial atypical mycobacterial infection.     

Advantage and disadvantage of KTP-532 laser tonsillectomy compared with conventional method

Objective: The purpose of this prospective study is to define the advantages and disadvantages of KTP laser tonsillectomy compared with those of the conventional method. Methods: Eighteen adult patients (ten male and eight female, ranging in age from 14 to 44 years) underwent KTP-532 laser tonsillectomy on one side and standard dissection surgery on the other side under general anesthesia. Results: By KTP laser tonsillectomy, there was a reduction in intraoperative blood loss and average time for removing one tonsil. On the second day of tonsillectomy, subjective pain on the KTP laser surgery side was less than that on the conventional surgery side. By the days 5–8, however, this effect disappeared and many patients indicated the laser side was more painful. There was no postoperative bleeding after KTP laser tonsillectomy. Laser surgery appeared to lead to slow wound healing during the whole post-operative course with significant difference compared with the conventional method. Disadvantages of postoperative pain and the possibility of secondary infection due to slow wound healing could be prevented by application of antibiotics and an anodyne. Conclusion: Considering safety and reliability during surgery, KTP laser was considered useful for adult tonsillectomy.