Office-based and microlaryngeal applications of a fiber-based thulium laser

OBJECTIVES: The carbon dioxide (CO2) laser is the premier dissecting instrument for hemostatic cutting and ablation during endolaryngeal surgery. However, microlaryngeal tangential dissection and office-based photoablation have been limited by the lack of a fiber-based delivery system. To address this limitation, a new laser was designed, which is a diode-pumped solid-state laser with a thulium-doped yttrium-aluminum-garnet laser rod. It produces a continuous-wave beam with a wavelength of 2013 nm and a target chromophore of water. This new laser functions similarly to a CO2 laser with the benefit of being delivered through a small glass fiber (0.365 to 0.550 mm). METHODS: A prospective pilot trial was done in 74 cases to explore applications of the new thulium laser. Thirty-two procedures were done with the laser used as an ablating instrument and topical anesthesia through a flexible laryngoscope (papillomatosis, 20; microinvasive carcinoma, 6; benign supraglottic lesions, 3; edema, 2; granuloma, (1). Forty-two procedures were done with the laser used as a cutting or ablating instrument for microlaryngeal dissection and general anesthesia. These included 27 partial laryngeal resections (supraglottis, 15; glottis, 10; subglottis, (2) and 8 posterior glottic laryngoplasties. The laser was also used as an ablative instrument during microlaryngoscopy in 7 cases. RESULTS: The thulium laser was used effectively in all cases, under both local and general anesthesia. In microlaryngeal dissection, electrocautery was not needed to control bleeding, even during cutting in the highly vascular paraglottic space. No complications related to the use of the thulium laser were experienced in any case. CONCLUSIONS: Because of the fiber-based delivery system, the 2013-nm continuous-wave thulium laser shows substantial promise for tangential dissection during microlaryngoscopy and soft tissue photoablation during office-based flexible laryngoscopy. Hemostasis was judged to be superior to experiences with the CO2 laser. In this pilot study, performing en bloc laryngeal cancer resection procedures was facilitated by use of the thulium laser.     

New-generation pulsed carbon dioxide laser: comparative effects on vocal fold wound healing

We investigated wound healing of vocal fold mucosal excisions using a canine model, comparing cold steel, the continuous wave (CW) carbon dioxide (CO2) laser, and a new, microsecond-pulsed CO2 laser. The thermal injury to the surrounding normal tissues produced by the laser increases the risk for scar formation and poor functional voice outcome. This injury may be reduced with a pulsed CO2 laser. Acute, 2-week, and 6-week studies of 15 dogs were made with blinded observers and nonparametric statistical analyses. Histologic comparison showed less thermal injury and scar formation in the vocal folds treated with the pulsed CO2 laser than with the CW CO2 laser. Functional outcomes as studied with laryngeal videostroboscopy revealed better vibratory characteristics with the pulsed CO2 laser as compared with the CW CO2 laser. No differences were seen on these measures between the pulsed laser and cold techniques. Pulsed CO2 lasers may offer the ease of laser laryngology and the superior wound healing of cold steel.     

The role of laser microsurgery in the treatment of laryngeal cancer

PURPOSE OF REVIEW: Transoral laser microsurgery has developed in recent years into a surgical method that combines a minimally invasive approach with the surgical precision of laser and microscope. The outcomes of laser microsurgical treatment of laryngeal carcinomas are reviewed and compared with the results of competitive standard procedures. RECENT FINDINGS: Laser microsurgery is widely acknowledged to have advantages in the treatment of early glottic carcinoma. In the treatment of glottic carcinoma causing impaired mobility or fixation of the vocal cord the role of laser surgery has not yet been definitively assessed. Based on published results, primary laser therapy can achieve local tumor control with a functional residual larynx in approximately 70-80% of cases. In patients with early or moderately advanced supraglottic carcinoma, laser microsurgery is comparable to open supraglottic laryngectomy in terms of local control and survival. With regard to organ preservation, laser microsurgery is comparable to open supraglottic laryngectomy but superior to radiotherapy. Microsurgery can preserve functionally important structures, allowing for early swallowing rehabilitation while avoiding tracheotomy. SUMMARY: This review elucidates the role of laser microsurgical partial resections of the larynx in comparison with other treatment modalities.     

Effect of CO2 laser on prostheses used in middle ear surgery

The use of CO2 laser is advocated in primary and revision stapes surgery. The aim of the study was to assess the effect of CO2 laser on stapes prostheses. CO2 laser was applied on several types of stapes prostheses and PORPs, with power settings suggested by the manufacturer (continuous wave, 2 W and 6 W; 0,05 s). Application of the laser on stainless steel or titanium prosthesis did not exert any effect on the structure of the prosthesis. The use of the laser on the Teflon piston caused superficial burning with power 2 W, and melting and holes in the piston with power settings at 6W. Similar plastipore prostheses were melting. Hydroxyapatite PORP shattered after application of the laser energy. Teflon and hydroxyapatite prostheses are easily damaged by the laser energy, therefore applying a laser on them should be avoided. CO2 laser can be used on stainless steel and titanium prostheses without risk of damaging them. However the possibility of transmission of heat to the vestibule has to be taken into consideration.     

Surgical lasers and soft tissue interactions

The different physical and biological qualities of the carbon dioxide, argon, and neodymium-YAG lasers provide the otolaryngologist and head and neck surgeon with a surgical tool with specific qualities and applications. The specific wave lengths of laser energy produce a varied soft tissue action. The carbon dioxide laser energy is absorbed by all biological tissues, whereas argon laser energy is an effective photocoagulator and penetrates into the subepithelial plane; the Nd-YAG laser creates a coagulation effect, which penetrates deep into the tissues. Each laser has specific physical qualities. The argon laser and the Nd-YAG laser can be transmitted through a flexible fiberoptic delivery system, whereas the carbon dioxide laser currently requires a rigid optical delivery system. The Nd-YAG and carbon dioxide lasers both require a second coincident aiming beam because of the invisibility of their laser energy, whereas the argon laser does not have such a requirement. The spot size of the laser beam can be much smaller for the argon laser than for the carbon dioxide laser. Protective lenses are necessary for the argon, carbon dioxide, and Nd-YAG lasers. The carbon dioxide laser energy is not transmitted through glass; thus most media (glass, plastic) are suitable to prevent any ocular injury. The argon laser requires a special yellowish protective mechanism, and the Nd-YAG laser requires a green protective lens mechanism. With further technical advances and improvements in the fiberoptic delivery system, smaller laser spot sizes, and changes in operating laser modes and color specifications of lasers, the advantages of laser surgery over conventional surgical techniques will become increasingly more apparent.     

„Ein-Schuss-CO2-Laser-Stapedotomie“

BACKGROUND: In order to further optimize the surgical technique with CO(2) laser in stapes surgery, a scanner system was used to obtain a footplate perforation of 0.5-0.6 mm with only one laser application ("one-shot" stapedotomy). PATIENTS AND METHODS: A total of 255 patients with otosclerosis were submitted to primary CO(2) laser stapedotomy with a SurgiTouch scanner. This study discusses the surgical technique and clinical results. RESULTS: An adequately large perforation diameter could be achieved with a single shot in 68% of the patients treated. In 14% of the patients, a second laser application at the same site was necessary. In 18% the perforation had to be enlarged by several slightly overlapping laser applications without using the scanner. There was no evidence of laser dependent inner ear affections. CONCLUSION: CO(2) laser, combined with modern scanner systems, is well suited for application in stapes surgery.     

Application of carbon dioxide and erbium:yttrium-aluminum-garnet lasers in inner ear surgery: an experimental study.

BACKGROUND: Surgery of the inner ear requires atraumatic techniques to preserve the sensory structures of the inner ear. With modern laser technology, surgery can be performed without mechanical contact, reducing the risk of direct mechanical trauma. However, energy transfer by laser light has the potential to induce damage by heating, pressure waves, or direct irradiation, depending on the properties of the laser and parameters of application. HYPOTHESIS: The application of laser systems in inner ear surgery may have an advantage over traditional techniques; the carbon dioxide laser in continuous mode with an automated scanning procedure and the erbium:yttrium-aluminum-garnet laser were compared with a mechanical technique, using a diamond drill. METHODS: A cochleostomy in the basal cochlear turn of guinea pigs was created. Thresholds in response to frequency-specific stimuli and clicks were established by recording compound action potentials, both before and after the procedure. RESULTS: The best results in terms of preservation of cochlear function were obtained with the diamond drill. However, a single ear had a complete loss after fracture of the cochlear wall. Mean threshold shifts observed with the carbon dioxide laser were slightly greater, showing mild high-frequency losses, although differences to the group of drilling were not statistically significant. Results with the erbium:yttrium-aluminum-garnet laser showed significantly higher degrees of hearing loss than the other two groups, predominantly in the high-frequency region. CONCLUSIONS: Mechanical opening of the inner ear using a microdrill can be performed with minimal hearing loss; however, it carries the risk of direct trauma to the inner ear. The carbon dioxide laser with a new scanning technology as a noncontact procedure is shown to be effective and safe. It can be regarded as a useful tool in inner ear surgery. The erbium:yttrium-aluminum-garnet laser has a greater potential to cause damage.     

Usefulness of ND:YAG laser in head and neck surgery

Nd:YAG laser is widely used in surgery as well as in otolaryngology and head and neck surgery for 25 years. This type of laser is characterized by low absorption in water and haemoglobin, deep penetration to the tissue and high ability for vessels coagulation. The laser light can be guided with glassfiber and can be focussed with handpices and micromanipulators. These characteristics make Nd:YAG laser very useful surgical instrument, especially in ORL and head and neck surgery. One institution's experiences, based on 300 operations with Nd:YAG laser are presented and discussed. Main indications to Nd:YAG laser operations in our material were: malignant neoplasms of oral cavity, pharynx and larynx, papillomas and haemangiomas of mucosa of upper respiratory tract, tracheal stenoses, scars of the larynx after partial laryngectomies and snoring and sleep apnoea syndrome. In our opinion, Nd:YAG laser has high usefulness in treatment of malignant and benign head and neck neoplasms, as well as in laryngeal scars and treatment of snoring. In cases of post intubation tracheal stenoses and in cases of post strumectomy bilateral paralysis of larynx the treatment results were not satisfactory. High usefulness of Nd:YAG laser results from very good coagulation ability and wide possibility of transmission of laser light with glassfiber.     

The use of CO2 laser in stapes surgery

Different microsurgical instruments and laser systems have been used to perform stapedotomy. We evaluated prospectively subjective intraoperative effect of CO2 laser use during stapedotomy performed under local anesthesia in 67 patients with otosclerosis. Hearing results were evaluated 4-8 months after surgery according to Committee on Hearing and Equilibrium guidelines. The CO2 laser was used 3-12 times to create a stapedotomy opening. The patients described the effect of laser application as a mild click. Neither tinnitus nor noise was reported during application of the laser on the footplate. The mean air conduction improved for 30+/-12.5 dB. There was no patient with deterioration of bone conduction (BC) in the group. Mean BC improvement was 8+/-9.1 dB. CO2 laser is a safe and effective tool in stapes surgery with no adverse effect on the cochlea. The use of the laser with manufacturer's parameters is not likely to produce unpleasant effects to the patients operated under local anesthesia.     

Phonatory outcome of 585 nm/pulsed-dye laser in the management of glottic leukoplakia

Objective

Vocal cord mucosectomy using pulsed-dye laser was assessed for its ability to completely remove lesions without deterioration of vocal quality in cases of vocal cord leukoplakia. To confirm the validity of a pulsed-dye laser, we retrospectively analyzed the treatment outcomes of patients who received surgery preceded by pulsed-dye laser and compared these with the outcomes of patients who received vocal cord mucosectomy using CO₂ laser.

Methods

Between February 2007 and June 2012, 36 patients were enrolled. Seventeen patients received vocal cord treatment with a CO₂ laser and 19 patients received operation with a pulsed-dye laser. To evaluate voice status, acoustic wave form analysis and electroglottography were done, and voice handicap index was measured before and after the operation.

Results

The entire lesion was removed in all patients. Compared to preoperative vocal parameters, the postoperative values for jitter were only improved in the pulsed-dye laser group. On stroboscopic findings, a diminution or lack of mucosal wave was observed in more CO₂ laser cases than pulsed-dye laser cases. Significant improvement in voice handicap index results was only observed in the pulsed-dye laser group.

Conclusion

Although long-term results with more patients are required to establish the validity of pulsed-dye laser, this study confirmed the merits of pulsed-dye laser for the en-bloc removal of vocal cord leukoplakia and improved voice outcome.     

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.     

The Versatile Contact Nd:YAG Laser in Head and Neck Surgery: An in Vivo and Clinical Analysis

Objective Lasers have been used in otolaryngology as a surgical instrument for more than 25 years, and the CO₂ laser has emerged as the most widely employed surgical laser in use today. However, recent technological advances have made the Nd:YAG laser a challenger as an effective photothermal surgical tool. Study Design and Methods This is a two‐part study. Tissue injury and healing profiles after application of both the CO₂ and Nd:YAG lasers are compared using an in vivo rat tongue model. A prospective clinical review based on the experience of 327 operative cases spanning a 7‐year interval using the Nd:YAG laser, highlighting its various applications and associated complications, is detailed. Results Comparable tissue and healing effects were noted with both lasers in the in vivo rat tongue model with no statistical differences. The clinical application of the laser showed wide versatility in the head and neck with a complication rate of 3%. Conclusion The Nd:YAG laser has proved equivalent in tissue damage and healing to the CO₂ laser. The Nd:YAG laser has proved itself to be an excellent and perhaps superior laser for use in head and neck surgery.     

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.     

Advances in laser skin surgery for vascular lesions

Recent advances in laser techniques for the treatment of vascular lesions have attempted to overcome the disadvantages of argon laser therapy. The trend toward a more selective treatment of these lesions, with preservation of as much normal tissue as possible, has been set. Minimal argon laser methods, yellow-dye lasers, and treatment with hematoporphyrin derivative photodynamic therapy extend the abilities of the laser surgeon to treat port-wine stains and other vascular lesions safely.     

Laser Photochemotherapy With Anthracyclines on Cultured Human Squamous Carcinoma Cells

A new treatment for cancer has been tested in vitro using light-sensitive anthracyclines followed by laser photoactivation, as described by several investigators. We previously reported 10-fold enhanced laser killing after 2 hours of incubation with daunomycin by cultured human carcinoma cells. This short-term uptake leads to drug localization in cytoplasmic and membrane sites prior to nuclear accumulation and topoisomerase inhibition. In the present study, daunomycin was incubated for 2 or 24 hours with P3 squamous carcinoma cells to directly compare cytoplasmic vs. nuclear drug targeting before and after KTP-532 laser activation. Monolayer cultures of the P3 cells sensitized with daunomycin for 2 hours, then chilled (4°C), and exposed to the KTP laser (532 nm, 94.2 J/cm²) had a 2- to 10-fold increased therapeutic response compared with drug or laser alone when measured by MTT tetrazolium assays. After 24 hours of incubation with daunomycin, the chemotherapeutic response of P3 tumor cells was amplified 2-fold by laser exposure. The results suggest that daunomycin and laser treatment can be combined for improved therapy of human cancer.     

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.     

Histologic Study of Oral Mucosa Wound Healing: A Comparison of a 6.0- to 6.8-µm Pulsed Laser and a Carbon Dioxide Laser

Incisional wound healing in the canine oral mucosa was histologically monitored at 3, 7, and 14 days after incision. Healing was compared from a scalpel, a carbon dioxide (CO₂) laser at 10.6µm, and the Vanderbilt free-electron laser tuned to 6.0, 6.45, and 6.8µm. A significant delay in wound healing was observed when incisions were made with the CO₂ laser, probably attributable to the excess thermal damage caused by the continuous-wave laser beam. When using the short pulsed, free-electron laser, a much smaller delay comparable to the scalpel wound healing was observed. This smaller delay tended to decrease with increasing tissue absorption. The results emphasize the greater importance of laser pulse duration rather than wavelength in relation to the subsequent wound healing.     

Effectiveness of Nd: YAG laser therapy on Japanese cedar pollinosis

Many have reported on the effectiveness of laser surgery therapy for perennial allergic rhinitis. However, the suppressive effects of laser irradiation on allergic rhinitis and its symptoms have not been reported in patients with pollinosis. This is because therapeutic effects on pollinosis are difficult to evaluate. The amount of pollen in the air varies during the year, and from year to year. Also, allergic symptoms develop due to exposure to the amount of pollen which is markedly influenced by the weather. In this study, the severity of allergic symptoms in the pollen season was compared between patients treated with early medication, non-treated patients and patients treated with preseasonal contact Nd: YAG laser surgery. Results suggests that laser surgery was effective in reducing the severity of symptoms in patients with cedar pollinosis. Symptoms were milder in the laser group than in the medication group and non-treated group for 3-4 weeks after the start of seasonal pollinosis, although no differences were noted in the early weeks. This may be explained by the fact that laser irradiation reduces the lamina propria of the nasal mucosa, the site of allergic reactions. This also suggests that allergic pollen can't penetrate the mucosal surface which shows squamous epithelization after laser irradiation.     

KTP-532 laser tonsillectomy: a comparison with standard technique

It has been stated that laser excision of oral and oropharyngeal lesions result in less intraoperative blood loss, reduced postoperative pain, and quicker wound healing, but few controlled studies have been done to substantiate these claims. A study was undertaken to examine the benefits of the KTP-532 laser in a group of 31 patients who underwent tonsillectomy. One tonsil was removed with the KTP-532 laser and the other was excised with conventional dissection and snare technique. Patients were not told which tonsil was removed with the laser. Pain, healing, and intraoperative blood loss comparing one side to the other was assessed. On the evening of surgery, 83% of patients selected the side that underwent standard dissection and snare tonsillectomy as the most painful. By midweek, however, approximately equal numbers of patients selected the laser side as the most painful. At the end of 1 week, 63% of patients felt more pain on the laser dissection side. Possible reasons for these results are discussed. Intraoperative blood loss was significantly reduced with the use of the KTP-532 laser, but healing was not accelerated.