Photoangiolysis with the 445-nm Blue Laser and the Potassium-Titanyl-Phosphate Laser: A Comparison

OBJECTIVES

Photoangiolytic lasers have yielded significant innovation in laryngeal surgery in the last 25 years. After the discontinuation of the potassium titanyl phosphate (KTP) laser, a novel 445-nm blue laser was developed. The optimal balance between a laser's desired tissue effects and collateral tissue damage is a major determinant of laser selection in microlaryngeal surgery. The shell-less incubation system for the chick chorioallantoic membrane (CAM) simulates the microvasculature of the human vocal fold and is useful for testing effects of laser settings and in simulated surgery. The aim of this study is to compare the tissue effects of the KTP and blue lasers using the shell-less CAM model.

METHODS

The shell-less incubation system contains: polymethylpentene film (used as a culture vessel), calcium lactate and distilled water supplementations. By using this system, the chick chorioallantoic membrane (CAM) can be fully exposed with a good field for surgery simulation. The effects of the 2 lasers (532 nm KTP and 445 nm blue) were quantified at clinically relevant energy settings and laser distances from target. Measures included imaging real-time vascular reactions in the CAM model, post-procedure histologic analysis of CAM tissue and temperature changes.

RESULTS

Vessel coagulation and rupture rates were less common with the blue laser compared with the KTP laser. Histologic analysis demonstrated less tissue disruption with the blue laser. Temperature changes were less with the blue laser.

CONCLUSION

In this CAM model with specific conditions, the blue laser reveals less tissue damage than the KTP laser. Suitable working distance and power setting of the laser are necessary for desired tissue effects.Level of Evidence: Level 3.

Use of the 445-nm Blue Laser for Management of Early Glottic Carcinoma: Preliminary 1-Year Results

OBJECTIVE

To analyze oncological efficacy and voice outcomes of the 445-nm blue laser (BL) in the treatment of early glottic carcinoma and compare results with the 532-nm potassium-titanyl-phosphate (KTP) laser.

STUDY DESIGN

Single institution, retrospective chart review.

METHODS

All patients who underwent microlaryngoscopic KTP or BL laser excision of early glottic carcinoma from 2018 to the present day with at least 1-year follow-up were included. Primary and recurrent disease, including radiation and surgical failures, were included. Demographic data, voice outcomes and oncologic outcomes were compared between the two laser groups.

RESULTS

Forty-nine patients met the inclusion criteria for the BL group and 88 for the KTP group, with average follow-up of 635 and 1236 days, respectively. Oncologic outcomes were not significantly different, with disease-specific survival rates of 95.9% for BL and 100% for KTP (p = 0.13), organ preservation rates of 98.0% for BL and 95.6% for KTP (p = 0.39), and local control rates of 93.9% for BL and 92.1% for KTP (p = 0.81). Both BL and KTP groups showed significant improvement in CAPE-V (p = 0.04, 0.006 respectively) and VHI-10 scores (p = 0.003, <0.00001) following surgery.

CONCLUSIONS

Photoangiolytic removal of early glottic carcinoma with BL appears to be equally safe and effective as with KTP laser at minimum one-year follow-up, and with excellent voice outcomes. Additional study will be warranted over time to assess long-term outcomes in BL patients.

LEVEL OF EVIDENCE

3 Laryngoscope, 2024.

Awake endoscopic laser surgery for early glottic carcinoma

The objective of this study was to demonstrate the oncologic efficacy of awake endoscopic laryngeal surgery in the treatment of T1-T2 glottic carcinoma. This is a retrospective study. Seventy-one patients with early glottic carcinoma (T1a- 26, T1b- 18, T2- 27) who underwent awake flexible endoscopic laryngeal surgery under local anesthesia and mild intravenous sedation were included in the study. In 64 cases (90.1%) only endoscopic tumor ablation by Nd:YAG laser (in 32.4% of cases being preceded by diathermy snare excision) was performed, and in 7 T2 cases postoperative radiotherapy was also offered. There were no complications during or after the endoscopic surgery. Ultimate control of disease, including salvage treatment, was obtained in 67 patients (94.4%). Cure without recurrence was achieved in 60 cases (84.5%). Local control without salvage radiotherapy or/and open surgery was achieved in 64 (90.1%) patients. Larynx preservation was obtained in 66 (93.0%) cases. At 5 years from the beginning of endoscopic treatment, 74.6% of the patients were alive and free of disease. The best results were obtained in the T1a group of treated patients, all the patients being free of disease with the preserved larynx. Awake endoscopic laryngeal surgery is a safe and oncologically efficient method of treatment of early glottic carcinoma that can be considered as an alternative to the traditional approach, primarily, for patients with risks/contraindications for radiotherapy, general anesthesia, and transoral microsurgery, and also for the patients who prefer to avoid general anesthesia with its related risks and would rather choose office-based laryngeal surgery.

Office-Based Blue Laser Therapy for Vocal Fold Leukoplakia: A Preliminary Report of 12 Cases

Objective

To report the efficacy of office-based blue laser therapy for vocal fold leukoplakia.

Study Design

A retrospective case series.

Setting

A tertiary care center.

Methods

A retrospective chart review of patients with vocal fold leukoplakia who underwent office-based blue laser therapy between July 2019 and October 2022 was conducted. The video recordings of their laryngeal examination and their voice evaluation were analyzed before and after surgical intervention.

Results

A total of 10 patients, eight with unilateral disease and 2 with bilateral disease, were included in this study. In total, 12 vocal folds with leukoplakia were treated. Nine had a single session and 3 had 2 sessions due to incomplete regression of the lesion after the first laser therapy session. Following treatment, 9 regressed completely (75%) and 3 regressed partially (25%). The mean Voice Handicap Index-10 (VHI-10) score decreased significantly from 15.4 ± 12.9 preoperatively to 3.8 ± 2.86 after surgery (p = .023). There was a statistically significant decrease in the means of grade, roughness, breathiness, asthenia, and strain (p < .05). There was also a statistically significant decrease in the jitter and shimmer percent (p = .008 and p = .048, respectively) and a significant increase in the maximum phonation time from 9.63 ± 3.83 to 13.54 ± 5.92 seconds (p = .039).

Conclusion

This preliminary study indicates that office-based blue laser therapy is an effective treatment modality for vocal fold leukoplakia.

Surgical Treatment of Early Glottic Cancer

The incidence of all head and neck malignancies is rising worldwide, with carcinoma of the larynx constituting approximately 1% of all cancers. Early glottic cancer responds quite favorably to surgical intervention due to its early presentation, coupled with the low rate of regional and distant metastases. This article focuses on various approaches to the surgical treatment of early glottic cancer. Details include the clinical and radiological evaluation of laryngeal cancer, the goals of treatment, current surgical options for early disease, approach to surgical resection margins and management of nodal disease, and complications associated with each treatment modality.

Outcomes of KTP Laser Ablation in Glottic Neoplasms: A Systematic Review and Meta-Analysis

OBJECTIVES

To evaluate the safety and clinical effectiveness of transoral laser microsurgery (TLM) with potassium-titanyl-phosphate (KTP) laser ablation for glottic neoplasms.

DATA SOURCE

MEDLINE via PubMed, SCOPUS, Web of Science, and Cochrane Library.

REVIEW METHODS

A systematic review and meta-analysis of studies assessing the safety and efficacy of KTP laser therapy in patients with early-stage glottic neoplasms.

RESULTS

Eight studies were included. After an average follow-up of 3.3 years, the overall survival and disease-free survival for patients who underwent KTP were 90.7% (95% CI 85%-96.5%) and 98.5% (95% CI 97.3%-99.8%), respectively. In the single-arm meta-analysis, the pooled estimate of recurrence was 7.7% (95% CI 3.4%-12%). The overall voice handicap index (VHI) estimate attributed to KTP in the single-arm meta-analysis was 6.76 (95% CI [3.05, 10.48]) and 5.21 (95% CI [2.86, 7.56]) within 6 months and after a one-year follow-up, respectively.

CONCLUSION

KTP laser ablation is a safe and effective method for treating patients with early glottic neoplasms. Laryngoscope, 2023.

Malignant Transformation in Glottic Dysplasia Treated With Photoangiolytic LASER - A Systematic Review and Meta-analysis

OBJECTIVE

This systematic review and meta-analysis seeks to characterize the rate of malignant progression among patients with laryngeal dysplasia treated with photoangiolytic laser and compare to prior systematic reviews of conventional surgical approaches.

METHODS

OVIDMedline, Pubmed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Google Scholar were searched, including terms related to patients with vocal fold dysplasia who were treated by angiolytic laser ablation. Some articles already known to authors or identified through hand searching were included.

RESULTS

Six articles with 155 cases were included. Two studies used potassium titanyl phosphate exclusively, one solely used the pulsed dye laser, and three studies utilized both laser types during the study period. The pooled overall mean of malignant progression for patients with laryngeal dysplasia treated with photoangiolytic laser was 12%, as calculated by conducting a meta-analysis of single arm proportion.

CONCLUSION

Laryngeal dysplasia is a premalignant lesion which confers a risk of progression to malignancy. After biopsy to establish the diagnosis there are multiple surgical techniques available for treatment with the goal of lesion eradication and voice preservation. In our review, there is a low malignant transformation rate for patients treated via with photoangiolytic laser.

Impact of Vocal Effort on Respiratory and Articulatory Kinematics

PURPOSE

The goal of this study was to examine the effects of increases in vocal effort, without changing speech intensity, on respiratory and articulatory kinematics in young adults with typical voices.

METHOD

A total of 10 participants completed a reading task under three speaking conditions: baseline, mild vocal effort, and maximum vocal effort. Respiratory inductance plethysmography bands around the chest and abdomen were used to estimate lung volumes during speech, and sensor coils for electromagnetic articulography were used to transduce articulatory movements, resulting in the following outcome measures: lung volume at speech initiation (LVSI) and at speech termination (LVST), articulatory kinematic vowel space (AKVS) of two points on the tongue dorsum (body and blade), and lip aperture.

RESULTS

With increases in vocal effort, and no statistical changes in speech intensity, speakers showed: (a) no statistically significant differences in LVST, (b) statistically significant increases in LVSI, (c) no statistically significant differences in AKVS measures, and (d) statistically significant reductions in lip aperture.

CONCLUSIONS

Speakers with typical voices exhibited larger lung volumes at speech initiation during increases in vocal effort, paired with reduced lip displacements. To our knowledge, this is the first study to demonstrate evidence that articulatory kinematics are impacted by modulations in vocal effort. However, the mechanisms underlying vocal effort may differ between speakers with and without voice disorders. Thus, future work should examine the relationship between articulatory kinematics, respiratory kinematics, and laryngeal-level changes during vocal effort in speakers with and without voice disorders.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.17065457.

Use of 532 nm Potassium Titanyl Phosphate Laser on Vocal Fold Scars Under Topical Anesthesia: A Pilot Study

OBJECTIVE

This pilot study aims to evaluate the efficacy of 532 nm potassium titanyl phosphate (KTP) laser under topical anesthesia in patients with vocal fold scars.

METHODS

A series of 18 patients with vocal fold scars of varying degrees were treated. The KTP laser was used under local anesthesia in the outpatient clinic. It was set to deliver 6 W of power using a continuous output mode. Close-to-contact mode was used for laser irradiation, and contact mode was used for ablation and excision of the lesions. Some of the patients received laser scar ablation on both vocal folds; the scarred vocal fold on one side and the hypertrophic vocal fold on the other. Parameters include glottic closure, amplitude, and mucosal wave pattern were measured using laryngeal stroboscopic examination. Aerodynamic and voice evaluations were carried out using maximum phonation time (MPT), jitter, shimmer, Voice Handicap Index questionnaire (VHI-30), and GRBAS scale.

RESULTS

In total, 21 surgeries were performed on 18 patients. Glottic closure, amplitude, and mucosal wave pattern showed improvement 2 months postoperatively (P < .05). There was significant improvement in the postoperative scores for VHI-30, VHI-emotional sub-scale, VHI-physical sub-scale, and GRBAS (P < .05). There was no significant difference in the MPT and VHI-functional sub-scale before and after the operation (P > .05). Re-adhesion of the anterior commissure was observed in 2 patients with Type III scars.

CONCLUSION

The 532 nm KTP laser is an effective tool for the treatment of vocal fold scars. Further research is required to determine if serial laser applications could improve outcomes for this challenging condition.

LEVEL OF EVIDENCE

Level IV.

Vocal Fold Cyst Formation after Photoangiolytic KTP Laser Treatment of Early Glottic Cancer

OBJECTIVE

The incidence of post-operative glottic cyst (POGC) formation in patients treated with transoral laser microsurgery with potassium-titanyl-phosphate laser (TLM-KTP) photoablation of early glottic carcinoma (EGC) has not previously been described.

METHODS

A retrospective chart review was performed to identify all patients with early glottic cancer who underwent with single-modality TLM-KTP at our institution. Each patient received regular follow up with videostroboscopy for tumor surveillance. New glottic cysts seen on surveillance examinations were noted and their management was documented.

RESULTS

A total of 33 patients met inclusion criteria. Eight patients (24%) developed POGC's within the original geographic perimeter of the cancerous vocal fold(s): 6 in the infraglottic region and 2 near the vocal process, at an average of 8 months after their initial cancer surgery. Of these 8 POGC's, 7 were at the periphery of the original tumor distribution and 1 was in the center of it. No POGC's were associated with any change in voice. Four of the 8 POGC's were phonosurgically excised, all without evidence of malignancy on pathology. The remaining 4 were monitored: 2 were stable for an average of 49 months of follow up; the remaining 2 resolved spontaneously by 7 and 31 months after first identification.

CONCLUSIONS

POGC's are a frequent sequela of TLM-KTP for EGC. While these results suggest that they are unlikely to represent submucosal recurrences, surgeons should have a low threshold to biopsy if there is clinical concern for such and should counsel patients pre-operatively about the potential for their formation.

[Photoangiolytic Lasers in Laryngology]

With photoangiolytic lasers like KTP (Potassium-Titanyl-Phosphate, 532 nm) lasers or the new "blue" laser (445 nm), even the smallest vessels and capillaries within the vocal fold can be treated without destroying the covering epithelium. This enables effective treatment of benign and malignant sub- and intraepithelial lesions of the vocal folds such as papilloma, edema, polyps, leukoplakia, dysplasia and capillary vessels while preserving the vibratory properties of the different layers of the lamina propria. Because photoangiolytic laser light can be routed through tiny glass fibers, office-based surgery with channelled flexible endoscopes are feasible as well as phonomicrosurgical operations under general anesthesia. Furthermore, the so called "blue" laser can cut tissues and thus broadens the technical armamentarium of the phonosurgeon.

KTP Laser Treatment of Early Glottic Cancer: A Multi-Institutional Retrospective Study

OBJECTIVES

The primary objectives were to report oncologic outcomes of transoral laser microsurgery with potassium-titanyl-phosphate (KTP) laser (TLM-KTP) ablation of early glottic cancer (EGC). The secondary objectives were to report vocal outcomes and to analyze factors that might influence outcomes.

METHODS

A multi-institutional, retrospective analysis of consecutive patients treated for T1 or T2 glottic squamous cell carcinoma undergoing TLM-KTP ablation with at least 2 years of follow-up was performed. Patients with prior radiation or surgery for laryngeal disease were excluded.

PRIMARY OUTCOME MEASURES INCLUDED

surgical failures requiring radiation or laryngectomy, disease-specific survival (DSS), and overall survival (OS). Secondary outcome measures included: pre- and postoperative Voice Handicap Index-10 (VHI-10) scores. The effects of smoking status, stage, and anterior commissure involvement on outcomes were analyzed.

RESULTS

Overall 88 patients met inclusion criteria (83% male, 79.5% current or former smokers). Mean age was 68 (standard deviation (SD): 12). Mean follow-up was 39.5 months (SD: 15.3). Staging included 50 T1a, 21 T1b, and 20 T2 tumors, including three metachronous second primaries. Radiation and/or laryngectomy avoidance was achieved in 87/88 (98.9%) of patients, inclusive of 24 patients requiring KTP re-treatments. Two patients had biopsy-proven recurrence (2.3%), but only 21 of 24 re-treated patients received a formal biopsy. No patients died from laryngeal cancer. DSS and OS were 100% and 92.3%, respectively. The mean VHI-10 scores were 19.3 preoperatively, 3.8 at 6-months postop, and 3.8 at 2-years postop. Smokers had a longer interval to re-treatment (P = .03), patients with T2 lesions had a shorter interval to re-treatment (0.02), and patients with T2 lesions presented with worse initial VHI-10 scores (0.002).

CONCLUSIONS

A multi-institutional, retrospective case series of TLM-KTP ablation of EGC demonstrated excellent oncologic outcomes when close surveillance and proactive re-treatments were utilized. Disease-specific survival, overall survival, and vocal function were excellent. Additional studies are necessary to further analyze the merits and risks of this treatment approach.

The Effects of Photobiomodulation on Vocal Fold Wound Healing: In Vivo and In Vitro Studies

Background: Photobiomodulation (PBM) is increasingly used in dermatology and dentistry due to its benefit of promoting wound healing and relieving pain; however, there is no corresponding research report on the application of PBM to vocal fold wound healing. Objective: To assess the potential wound-healing effects of PBM on the vocal folds via in vivo and in vitro experiments. Materials and methods: In in vitro study, vocal fold fibroblasts (VFFs) were irradiated under a diode laser with wavelength of 635 nm at energy density of 8 J/cm². The Cell Counting Kit-8 (CCK-8) assay was used to study the viability of VFFs, and the gene expressions of COL1A2, COL3A1, IL-6, HAS2, and COX-2 were investigated by real-time polymerase chain reaction (RT-PCR). In in vivo study, 15 rabbits were used. Lamina propria of the left vocal folds of 12 rabbits was unilaterally stripped, and 6 of them were treated with PBM. The remaining three rabbits served as normal controls. After 3 months, all animals were sacrificed to obtain histological results. We used laryngoscope to record images of the healing phase. Results: Irradiation with energy density of 8 J/cm² resulted in a 2.8% increase in cell proliferation (p < 0.05). However, the difference between the experimental and the control group became larger after 48 and 72 h of subsequent irradiation. RT-PCR results showed that the expression of COL1A2, COL3A1, and HAS2 was higher, and the expression of IL-6 and COX-2 was lower. Histological examination showed that, compared with the injury group, hyaluronic acid (HA) increased significantly, collagen deposition decreased, and the configuration of collagen was more organized after PBM treatment. Conclusions: PBM can inhibit inflammatory reaction and promote the secretion of HA to decrease the deposition of collagen and regenerate vocal fold tissue without scar.

Angiolytische Laserverfahren am Kehlkopf

Durch transorale Lasermikrochirurgie wurden bei der Larynxkarzinomtherapie temporäre Tracheotomien reduziert, die Organerhaltraten erhöht und funktionelle Resultate verbessert. Goldstandard für die laserbasierte transorale Resektion eines Larynxkarzinoms ist der Einsatz des CO2-Laser, dabei sind onkologische Radikalität und postoperative Stimmfunktion individuell abzuwägen. Angiolytische Lasereffekte ermöglichen eine Beeinflussung des Tumormikromilieus durch zielgerichtete Gefäßobliteration und Blockierung der Angiogenese mit Schonung von schwingungsfähigem Gewebe für eine gute Stimmfunktion. Mit der Verabschiedung der S3-Leitlinie zur Diagnostik, Therapie und Nachsorge des Larynxkarzinoms wird eine nationale evidenzbasierte Standardisierung gefördert. International nimmt die Evidenz zur Kalium-Titanyl-Phosphat-Laser-Therapie laryngealer Schleimhautdysplasien und von T1a-Larynxkarzinomen zu. Auch bei juveniler Papillomatose und der Stützlaryngoskopie unter Narkose sowie für ausgewählte Patienten in Lokalanästhesie werden angiolytische Laser eingesetzt.

The Use of 532-Nanometer-Pulsed Potassium-Titanyl-Phosphate (KTP) Laser in Laryngology: A Systematic Review of Current Indications, Safety, and Voice Outcomes

OBJECTIVE

To investigate the indications, efficacy, safety, and outcomes of potassium-titanyl-phosphate (KTP) laser procedures for treatment of laryngeal disease.

METHODS

PubMed, Cochrane Library, and Scopus were searched for studies providing information about the indications, efficacy, and safety of both in-office and operative suspension microlaryngoscopy KTP laser procedure in treatment of laryngeal disease. Diagnostic criteria and clinical outcome evaluation of included studies were analyzed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria.

RESULTS

Of the initial screened 140 papers, 17 met our inclusion criteria. Six papers involved KTP laser procedures for benign and malignant vocal fold lesions in suspension microlaryngoscopy only, 10 papers focused on only in-office KTP laser procedures for benign vocal fold lesions, and 1 paper included both in-office and suspension microlaryngoscopy procedures. The following lesions may be considered as indications for KTP laser procedures: Reinke's edema, sulcus vocalis, vocal fold hemorrhage, polyp, granuloma, cyst, scar, papillomatosis, dysplasia, leukoplakia, and early vocal fold malignancies. Irrespective of the types of procedure (in-office vs suspension microlaryngoscopy), the KTP laser is associated with a low complication rate and overall good vocal fold vibration recovery. There is an important heterogeneity among studies concerning laser settings, indications, and outcomes used for the assessment of treatment effectiveness. There are no controlled studies directly comparing KTP laser with other lasers (ie, carbon dioxide laser).

CONCLUSION

The use of KTP laser procedures for treatment of laryngeal disease has increased over the past decade, especially for office-based management of vocal fold lesions. Future controlled studies are needed to compare the safety and outcomes of the KTP laser to other techniques.

Implication and Management of Incidental Oropharyngeal Papillomas-A Retrospective Case Series Review

INTRODUCTION

Incidental papillomas of the pharynx can be found while examining the nasopharynx, oropharynx, and hypopharynx for other disorders of the head and neck. Purpose of the study is to explore the location, biopsy protocol, and decision to perform office-based versus operative management via potassium titanyl phosphate (KTP) laser when an oropharyngeal papilloma is discovered incidentally.

METHODS

A retrospective review of the senior author's patient population was performed using Current Procedural Terminology and/or International Classification of Diseases codes to identify patients who had KTP laser removal of incidental oropharyngeal papillomas. Patients were included based on the incidental nature of the papilloma and confirmed pathology report of squamous papilloma. Demographics, presenting complaint, lesion location, pathological analysis, type of intervention, and outcomes were recorded. When available, human papillomavirus (HPV) subtype was noted.

RESULTS

A total of 26 cases were identified, 13 females and 13 males. The median age at time of surgery was 58 years (range: 21-77). The most common presenting symptoms were difficulty swallowing and throat pain. The most common locations were the base of tongue, uvula, tonsils, and the soft palate. Of the 26 patients, 23 patients received KTP laser ablation therapy as an office-based procedure, while the remaining 3 were performed under general anesthesia in the operating room. Only 5 patients had a recorded recurrence that required reoperation. There were no operative or postoperative complications. There were 16 biopsy samples tested for HPV, where 12 were negative for HPV and 4 were positive for HPV.

CONCLUSION

Oropharyngeal papillomas, when present, can be found incidentally during examination of the oropharynx for other symptoms. Office-based biopsy and KTP laser is a safe and efficient means of identifying and removing most oropharyngeal papillomas.

Histologic effect of the potassium-titanyl phosphorous laser on laryngeal papilloma

Objectives

Tissue effects occurring with potassium‐titanyl phosphorous (KTP) laser treatment are difficult to quantify due to the multiple variables that affect not only the fluence (energy delivered) but also the laser–tissue interaction. This histopathologic analysis of recurrent respiratory papilloma (RRP) removed after treatment with KTP laser therapy permits correlation of histologic effect with method of laser treatment.

Methods

The histopathology of RRP resected specimens in a single patient was compared following treatment with KTP laser in contact and non‐contact modes as documented with intraoperative photography and video imaging.

Results

Epithelial‐sparing injury selective to the microvasculature was identified on histopathologic assessment of a specimen treated with noncontact angiolysis. Highly cauterized papillomatous epithelium without identifiable vascular structures was identified on tissue removed after treatment with the KTP laser in contact mode.

Conclusion

The histopathologic assessment of acute KTP laser effect on papilloma permits correlation between technique of application and tissue effect. Similar assessments may be helpful to modify dosimetry for individual patients requiring repeated treatment and may also assist in refining the development of existing KTP laser treatment classification systems.

Level of Evidence

4

Randomized controlled single-blinded clinical trial of functional voice outcome after vascular targeting KTP laser microsurgery of early laryngeal cancer

Background

Local control rate (LCR) of early glottic cancer is high after radiation therapy or transoral laser microsurgery (TLM). The aim of this study was to investigate functional voice outcome after TLM using a microvessel‐ablative potassium‐titanyl‐phosphate (KTP) laser in comparison with a gold standard cutting CO₂ laser.

Methods

The primary end point of this prospective, randomized, single‐blinded, clinical phase II study with control group was voice outcome during a follow‐up of 6 months assayed by Voice Handicap Index (VHI‐30)‐questionnaires in patients with unilateral high‐grade dysplasia, carcinoma in situ or early glottic cancer undergoing TLM‐KTP (n = 8) or TLM‐CO₂ (n = 12). The secondary end point was LCR.

Results

Starting from the 9‐week‐follow‐up visit, TLM‐KTP yielded significantly reduced VHI scores compared to TLM‐CO₂. No relapse occurred after TLM‐KTP in contrast to one recurrence after TLM‐CO₂ within 6 months.

Conclusion

Multicenter phase II or III studies on voice outcome or local control rate after TLM‐KTP in early glottic cancer are warranted enrolling larger patient cohorts.

Glottic Carcinoma in Young Patients

Introduction:

Recent reported evidence indicates that vocal cord carcinoma is evolving similarly to oropharyngeal cancer with an increasing number of patients without a smoking history having human papillomavirus (HPV) disease. Observations also suggest that an increasing number of patients who present with glottic carcinoma are younger than has been reported in the past. Therefore, an investigation was done to examine the incidence of glottic carcinoma in patients 30 years old (y/o) or younger.

Methods:

A retrospective review was done with Institutional Review Board approval to evaluate the incidence of patients 30 y/o or younger presenting with glottic carcinoma in 2 symmetric-length time periods over 28 years. These data were comprised from glottic cancer patients evaluated by the senior author (S.M.Z.) at the Massachusetts Eye and Ear Infirmary (July 1990-June 2004) and subsequently at the Massachusetts General Hospital (July 2004-June 2018). HPV testing was done on those patients identified as having a disease process at 30 y/o or younger.

Results:

Between July 1990 and June 2018, 353 patients were diagnosed with glottic carcinoma. From July 1990 to June 2004, there were 112 patients, with none being 30 y/o or younger. From July 2004 to June 2018, 241 patients were diagnosed with glottic carcinoma; 11 patients (7 females, 4 males) were 30 y/o or younger. Of the 11 patients, 3 (1 female, 2 males) were 10 to 19 y/o, 3 (2 females, 1 male) were 20 to 25 y/o, and 5 (4 females, 1 male) were 26 to 30 y/o. Moreover, 10 of the 11 cases were tested and were positive for high-risk HPV. None of the 11 glottic cancer patients had been previously treated for benign recurrent respiratory papillomatosis although it was initially suspected prior to biopsy due to the morphology of the lesions and the patients’ young age. Three of 11 had a history of smoking; all 3 had less than 3 pack-years. One of the 11 glottic cancer patients was treated with serial Cidofovir injections that resulted in dramatic acceleration in the growth of the cancer.

Conclusion:

Historically, glottic carcinoma is considered to be a tobacco-induced disease associated with a multidecade process of initiation, promotion, transformation, and progression. However, recent published evidence shows that glottic carcinoma can be an HPV-related disease with increasing incidence in nonsmokers. It isn’t surprising that alternate malignant pathways may have a different timeline. In this investigation, an increased incidence of HPV-positive glottic cancer in patients 30 y/o or younger was documented in the past 14 years. This finding further supports the concept that glottic carcinoma is an evolving disease, and it demonstrates the increasing importance of discriminating potential glottic carcinomas in young patients from benign low-risk HPV recurrent respiratory papillomatosis.

Outcomes of Treating Early Glottic Neoplasms With a Potassium Titanyl Phosphate Laser

Objectives:

The aim of this study was to assess the outcome of treating glottic dysplasia and early squamous cell carcinoma (SCC) with potassium titanyl phosphate (KTP) photoangiolytic laser ablation.

Methods:

Patient demographics, comorbidities, and tumor characteristics were recorded. Perceptual, patient-reported, and objective voice outcomes were assessed. Use of treatment modalities in addition to the KTP laser, development of locoregional or metastatic SCC, and overall survival were recorded.

Results:

There were 23 patients with glottic dysplasia and 18 patients with glottic SCC. Mean age at treatment was 69 years. Most patients (95%) were male. Posttreatment fundamental frequency fell from 132 ± 35 to 116 ± 24 Hz ( P = .03). Overall, 61% of patients achieved a normal voice. There was a learning-curve, and most treatment failures occurred in the first half of the series. Five-year KTP-only disease-control rates were 87.1% and 53.5% for dysplasia and malignancy, respectively. Five-year overall survival was 56%, with no laryngectomies or deaths due to SCC.

Conclusions:

Ablating dysplasia and early glottic cancer using a KTP laser is a viable treatment option. It has a learning curve and a failure rate but, in this series, no ultimate loss of oncologic control. Its introduction into clinical practice should be managed carefully in the context of multidisciplinary cancer care.

Level of Evidence:

4.

Can "Indirect" Contact Laser Surgery be Used for Fluorescence-Image Guided Tumor Resections? Preliminary Results

Ensuring the complete removal of tumor tissue is the main challenge during resection operations. Recently, a technique of “indirect” contact laser surgery has been developed. In this study we assess the possibility of using such surgery for fluorescence image-guided tumor resection. Mouse colon adenocarcinoma CT-26 cells stably expressing the fluorescent protein mKate-2 was used as the tumor model. Resections of the tumor nodes were performed with either a scalpel blade, a laser scalpel with a bare tip, or a laser scalpel with a strongly absorbing coating on the fiber tip. Tumor-positive resection margins were detected using an IVIS Spectrum fluorescence imaging system. After tumor resection with the scalpel blade over half of the animals needed one additional resection to remove residual tumor cells. Animals in this group showed tumor recurrence within 7 days. Fluorescence imaging of the tumor bed, performed after resection to assess the presence of tumor cell clusters, was sufficiently effective only with a bloodless resection. The laser scalpels both with the bare tip and with the strongly absorbing coating on the tip provided such bloodless tumor resection in contact mode. Fewer animals required additional resections when the bare tipped scalpel was used and this also resulted in a reduction in tumor recurrence. After resections were carried out with the laser scalpel with the strongly absorbing coating on the tip, fluorescence was detected in the operative field and this led to undertaking additional resections, although subsequent investigation suggested that this was “false” fluorescence, resulting from the effects of the scalpel rather than the presence of residual tumor cells. The method of laser resection with a strongly absorbing coating on the tip therefore did not appear to demonstrate definite advantages over laser resection with a bare tip when removing tumors.

Outcomes and patterns of failure of sarcomatoid carcinoma of the larynx: The Mayo Clinic experience

OBJECTIVES/HYPOTHESIS

Sarcomatoid carcinoma is a rare variant of squamous cell carcinoma of the head and neck. No consensus exists on its management. Our aim was to present our outcomes.

STUDY DESIGN

Retrospective study. Median follow-up 45 months.

METHODS

There were 38 patients with pathologically confirmed sarcomatoid carcinoma of the larynx treated at the Mayo Clinic from 1990 to 2014. Statistical analysis of overall survival (OS), progression-free survival (PFS), and local control (LC) were conducted using the Kaplan-Meier method.

RESULTS

The majority of patients were elderly males (92%) with a smoking history (74%) presenting with early-stage disease (71%). Surgery alone was the primary treatment in 27 patients (71%). Nine patients (25%) were treated with adjuvant radiation due to initial stage or high-risk pathologic features. Median radiation dose to the primary/surgical bed was 65 Gy (range, 60.3-75.0 Gy). A total of 15 patients (39%) had tumor recurrence, majority being local (n = 12). Sixty percent (n = 9) had multiple local recurrences. Five-year OS, PFS, and LC were 63%, 46%, and 72%, respectively. Subgroup analysis by stage I versus higher stages (II-IV) showed an OS of 80% versus 43% (P = .030), PFS of 65% versus 18% (P = .003), and LC of 84% versus 57% (P = .039).

CONCLUSIONS

Sarcomatoid carcinoma of the larynx is rare, and frequently presents at an early stage in older men with history of smoking. Based on our outcomes and patterns of failure, it appears early-stage tumors are treated appropriately with single-modality therapy, whereas more advanced tumors require multimodality therapy. Validation in a larger cohort is warranted.

LEVEL OF EVIDENCE

4. Laryngoscope, 128:373-377, 2018.

The role of separate margins sampling in endoscopic laser surgery for early glottic cancer

CONCLUSIONS

Sampling surgical margins in trans-oral laser microsurgery for early glottic squamous cell carcinoma (SCC) may allow for increased local control rate, although with no difference in local control by endoscopic treatment alone.

OBJECTIVE

To further delineate the role of routinely sampling separate surgical margins, in patients with early glottic SCC undergoing endoscopic laser resection.

METHODS

A retrospective case control study. One hundres and two early glottic cancer patients staged Tis-T2 underwent endoscopic laser surgery with curative intent as the primary treatment. Separate margins from the surgical bed were sampled following complete tumor resection in 64 patients; in 38 patients no margins were sampled.

RESULTS

Margin sampling showed a tendency towards reduced risk for local recurrence, adjusted HR = 0.439 (p-value = 0.096). However, there was no difference in local control by endoscopic treatment alone. The patients with sampled margins were further divided based on margins' status: 39 (61%) had negative margins, and 25 (39%) had positive margins. Compared with negative margins, patients with positive margins showed increased risk for recurrence, adjusted HR = 8.492 (p = 0.008). When margins were not sampled the risk for local recurrence was increased compared to negative margins (adjusted HR = 7.875, p-value = 0.008), and relatively comparable to what was observed when sampled margins were positive (adjusted HR = 0.927, p-value = 0.88).

Transoral robotic surgery for early glottic carcinoma involving anterior commissure: Preliminary reports

BACKGROUND

Transoral robotic surgery (TORS) for early glottic cancer has been reported, but the issue of anterior commissure involvement has seldom been addressed. Therefore, the purpose of this study was to preliminarily report the treatment results of TORS in this disease entity.

METHODS

Eight patients with T1 and T2 glottic carcinoma with anterior commissure involvement were selected to receive TORS. The clinical parameters, including rates of adjuvant radiotherapy (RT), survivals, as well as organ and function preservation, were retrospectively analyzed.

RESULTS

TORS was successfully performed in all patients without temporary tracheostomy. There were no major complications and no patient received adjuvant RT to the larynx after surgery. With a mean follow-up of 40 months, all patients survived with their larynx preserved and no local recurrence, tracheostomy, or tube feeding dependence.

CONCLUSION

TORS is a feasible approach for selected patients with early T classification glottic carcinoma with anterior commissure involvement. The preliminary oncologic and functional outcomes are satisfactory. © 2015 Wiley Periodicals, Inc. Head Neck 38: 913-918, 2016.

Analysis of Potassium Titanyl Phosphate Laser Settings and Voice Outcomes in the Treatment of Reinke’s Edema

Objective:

Despite increased clinical utility of the 532-nm potassium titanyl phosphate (KTP) laser, no studies have examined outcomes for Reinke’s edema (RE) as a function of laser parameters and initial treatment effects. Variability in delivery parameters, fiber-to-tissue distance, and immediate end-tissue effects limits universal application of existing study outcomes. We examine voice outcomes using standardized treatment classification, providing justification for laser parameter selection and immediate tissue effect in clinical use.

Methods:

Retrospective review of 9 patients who underwent KTP laser treatment for RE. Demographics, RE severity, laser settings, total laser energy, and immediate tissue effects were correlated with quantified voice outcomes.

Results:

An average of 157 joules (6-640 J) was delivered over a 0.369-second exposure time (0.1-0.9 seconds). Immediate tissue effects varied from nonablative treatment (type I and type II) to ablation without tissue removal (type III). Overall, Voice Handicap Index-10 (VHI-10) decreased by 8.23; improvement was most pronounced with type II treatments (delta VHI-10 = 12). No complications were encountered.

Conclusion:

Potassium titanyl phosphate laser can be safely and effectively used to improve voice in RE patients regardless of severity. This is the first study to provide detailed information on laser settings, energy delivery, and treatment effect in RE management; these results may guide clinical use of this modality, especially for novice laser surgeons.

Oncologic Efficacy of Angiolytic KTP Laser Treatment of Early Glottic Cancer

Objective:

Angiolytic laser removal of early glottic cancer with ultra-narrow margins was reported in a pilot study 5 years ago as an innovative surgical treatment strategy to better preserve vocal function. Subsequently, in a cohort of > 90 patients, enhanced voice outcomes were achieved and there was diminished need for post-treatment phonosurgical reconstruction. However, the initial pilot study examining oncologic efficacy had a limited number of patients and most did not have 3-year follow-up. Consequently, further analysis of the oncologic efficacy is valuable.

Method:

Retrospective review.

Results:

One hundred seventeen patients (T1a-71, T1b-11, T2a-10, T2b-25) underwent potassium-titanyl-phosphate (KTP) laser treatment of early glottic cancer with a minimum 3-year follow-up (average = 53 months). The “b” designation delineated bilateral disease. Disease control for T1 and T2 lesions was 96% (79/82) and 80% (28/35), respectively. All 10 recurrences were treated with radiotherapy. Fifty percent (5/10) were controlled with radiotherapy, and the other 5 died of disease. Larynx preservation and survival were achieved in 99% (81/82) with T1 disease and 89% (31/35) with T2 disease.

Conclusion:

This investigation provides further evidence that angiolytic KTP laser removal of early glottic cancer with ultra-narrow margins is an effective oncologic treatment strategy. Radiotherapy was preserved for future use in more than 90% of patients. Since a majority of patients are referred by an otolaryngologist to undergo treatment of early glottic cancer with radiotherapy, this investigation provides compelling information to reappraise this paradigm.

Evaluating the Effects of a 532-nm Fiber-Based KTP Laser on Transoral Laser Surgery Supplies

Objective

The KTP laser has become commonplace in transoral head and neck surgery. The interactions of this laser with commonly used supplies in transoral surgery have not been formally examined. This study evaluates the effects of the KTP laser on surgical supplies.

Study Design

Experimental study.

Setting

The study was conducted in an empty operating room at a university-affiliated medical center.

Methods

An Aura XP 532-nm KTP laser with a 600-nm fiber was used in pulsed and continuous modes. The beam was focused at the shaft and balloon of 3 “laser-safe” endotracheal tubes (ETTs), a polyvinyl chloride (PVC) ETT, and a Codman surgical patty. Time to penetrate was recorded.

Results

The KTP laser beam was unable to penetrate any of the laser-resistant ETTs. It did react with the black number markings on the PVC ETT by producing sparks but was unable to penetrate the shaft of the ETT. The KTP laser was nonreactive with all ETT cuffs except in 1 of 3 trials with the outer balloon cuff of a Rusch Lasertubus ETT when the laser was used in a continuous mode. The KTP laser caused the production of a flame upon contact with the blue radiopaque strip of the surgical patty, even when the patty was wet.

Conclusion

This study demonstrates that a number of safe ETT options may be used during transoral laser microsurgery with a KTP laser. In addition, Codman surgical patties are shown to be a significant fire risk in KTP laser surgery.

The utility of the potassium titanyl phosphate laser in modulating vocal fold scar in a rat model

OBJECTIVES/HYPOTHESIS

We hypothesize that the KTP laser has the potential to augment wound healing in a rat model, and this modality may serve as a therapeutic tool for the management of vocal fold fibrosis.

STUDY DESIGN

Prospective, laboratory animal study.

METHODS

Rats were subjected to either vocal fold injury ± KTP laser treatment at low energy to simulate clinically relevant endpoints. In addition, cohorts were subjected to therapeutic KTP laser alone. Endpoints included the analyses of gene expression data related to the acute inflammatory response and extracellular matrix deposition and organization.

RESULTS

Therapeutic KTP treatment was associated with an additive effect on inflammatory gene expression in the context of the injured rat vocal fold mucosa. A similar additive effect was observed for matrix metalloproteinase gene expression, similar to data previously reported in the dermatology literature. However, histologically, the KTP had little effect on established vocal fold fibrosis.

CONCLUSIONS

These data are the first to attempt to provide mechanistic insight into the clinical utility of angiolytic lasers for vocal fold scar. Similar to previous data obtained in the skin, it appears that these effects are mediated by MMPs.

Voice outcomes for photoangiolytic KTP laser treatment of early glottic cancer

OBJECTIVES

Surgery and radiotherapy routinely provide high cure rates in treating early glottic cancer. Therefore, key metrics for success are optimal voice outcome and preservation of future cancer treatment options. Remarkably, there is a paucity of pretreatment versus posttreatment voice outcome data. Angiolytic KTP (potassium titanyl phosphate) laser treatment of early glottic cancer with ultranarrow margins was initiated to better preserve vocal function. Given that effective oncological results have been achieved, it was hypothesized that this approach would also result in improved posttreatment measures of vocal function that more closely approximate historical norms than pretreatment values.

METHODS

Pretreatment and posttreatment voice outcome data were obtained for 92 patients (64 with T1 cancer and 28 with T2 cancer) who underwent 532-nm KTP laser treatment of early glottic cancer in a study design in which each patient essentially served as his or her own control. The evaluations included objective measures (acoustic and aerodynamic) and patients' self-assessments of vocal function (Voice-Related Quality of Life; V-RQOL). A series of mixed analyses of variance were conducted for all vocal function measures, with tumor stage and depth of invasion as the between-subjects variables and time (presurgery versus postsurgery) as the within-subject variable.

RESULTS

There were statistically significant (p < or = 0.05) postoperative improvements for acoustic (perturbation and noise-to-harmonics ratio) and aerodynamic (subglottic pressure and vocal efficiency) measures of vocal function, as well as for V-RQOL assessment.

CONCLUSIONS

Comprehensive pretreatment and posttreatment voice measures in a large patient cohort demonstrated that the KTP laser significantly improved postoperative vocal function in patients with early glottic cancer. Furthermore, radiotherapy was preserved as an oncological treatment option.

KTP 532 nm laser for laryngeal lesions. a systematic review

OBJECTIVE

To evaluate the effectiveness and safety of the 532 nm potassium titanyl phosphate (KTP) laser for vocal fold surgery.

STUDY DESIGN

Systematic literature review.

METHODS

Our systematic review was conducted using the meta-analysis of observational studies in epidemiology guidelines. We applied the criteria of the Oxford Centre for Evidence-based Medicine to assess the level of evidence.

RESULTS

We identified seven observational studies of eight case series, which reported a total of 243 KTP procedures carried out for vocal fold lesions: two series each concerning ectasias and varices, early glottic cancer, and recurrent papillomatosis, and one series each for keratosis with dysplasia and various benign laryngeal pathologies. There was also a retrospective review of the use of KTP laser in 387 endoscopic laryngeal surgeries. No studies compared the use of KTP laser with that of other technologies. Thus, according to the Oxford criteria, there is only level 4 evidence of KTP's efficacy and safety. In selected cases, the KTP instrument can be used without general anesthesia in the clinic setting.

CONCLUSIONS

The use of KTP laser for laryngeal surgery is still relatively innovative. Several surgeons have found KTP laser to be the equivalent of, or superior to, the CO2 or pulsed dye lasers, and none have reported inferiority. However, there are currently no published data to support these conclusions. To establish equality/superiority, it is desirable that further evidence of efficacy and safety be obtained, either through randomized controlled trials or at least through well-documented prospective observational studies with reporting of all relevant input and outcome data.

High-speed videoendoscopic analysis of relationships between cepstral-based acoustic measures and voice production mechanisms in patients undergoing phonomicrosurgery

OBJECTIVES

There is increased interest in using cepstral-based acoustic measures for objective clinical voice assessment because of their apparent advantages over more time-honored methods, but there is a paucity of information about how these newer measures relate to underlying phonatory mechanisms.

METHODS

We investigated the relationships between the acoustic cepstral peak magnitude (CPM) and high-speed videoendoscopy (HSV)-based measures of vocal fold phonatory function in 20 subjects who underwent phonomicrosurgery for vocal fold lesions. Acoustic and imaging data were acquired during sustained vowel phonation before and after surgery.

RESULTS

The changes in the measures between presurgical and postsurgical assessments showed that the CPM correlated significantly with an HSV-based measure combining fundamental frequency deviation and average speed quotient (r = 0.70; p < 0.001) in a multiple linear regression, and that the variation in the CPM could also be attributed to trading relationships between the HSV-based measures of vibratory phase asymmetry and glottal closure.

CONCLUSIONS

These initial results demonstrate that the clinical utility of cepstral-based measures can be enhanced by a better understanding of how these acoustic measures relate to underlying phonatory mechanisms. The CPM seems to integrate information about aperiodicity in vocal fold vibration, the relative speed of glottal closure, and estimates of glottal noise generation.

Submucosal neoplasms of the laryngeal introitus

BACKGROUND

The differential diagnosis of endolaryngeal mesenchymal neoplasms includes a wide spectrum of benign and malignant pathologies, which have been rarely photo-documented and assessed as a group.

METHODS

Non-epithelial neoplasms of the endolarynx seen at our centre from 2002 to 2011 (n = 38; 36 treated at our institution) were retrospectively reviewed, with attention to clinical presentation, radiographic imaging, operative management, histology, and pre- and post-operative endoscopy. Submucosal squamous cell carcinomas, mucosal cysts, amyloid and Teflon granulomas were excluded.

RESULTS

Twenty-three of a total of 36 patients underwent definitive endoscopic surgical treatment. Supraglottic pathologies included lymphoma, lipoma, neuroendocrine carcinoma, lymphangioma, oncocytoma, haemangioma, synovial cell sarcoma and benign spindle cell neoplasm. Transglottic pathologies included synovial cell sarcoma and granular cell tumour. Glottic pathologies included granular cell tumour, osteoma, rhabdomyoma, rhabdomycosarcoma and myofibroblastic sarcoma. Subglottic pathologies included chondrosarcoma, neurofibroma, adenoid cystic carcinoma and vascular malformation.

CONCLUSION

The site of origin, degree of malignant behaviour and sensitivity to adjuvant treatment determined the course of surgical management, i.e. endolaryngeal versus transcervical, and limited removal versus wider resection.

[The application of KTP laser in otolaryngology - 3 years experience]

INTRODUCTION

The KTP laser is popularly called the green laser is a type of Nd: YAG laser zawdzięczający its name from the additional element of KTP crystal which is a wavelength of 532 nm.

AIM

The aim of this paper is to present our 3-year experience in the application of KTP laser in otolaryngology.

MATERIAL

In the Department of Otolaryngology, CSK MON Military Medical Institute in Warsaw from 2008, performed 211 operations using the green laser. The study group was 89 women and 122 men aged 12 to 94 years (mean age 53.2 years).

METHODS

The surgery was performed 15-watt KTP Aura laser. All guestrooms are fibers with a diameter of 0.2, 0.4 and 0.6 mm, and guides for inserting the fiber ends are not. Results: In 3-year period have made a 211 KTP laser surgery including the nasal cavity, mouth, larynx and trachea, and the outer ear. In the procedure adopted one day 76 people, and at least 111 patients stayed in hospital for 4 days.

RESULTS

In our material patients after UPPP tonsillectomy and operations, in addition to a negligible bleeding during surgery, rarely also had late bleeding (5%). In our clinic konchoplastyki performed based on the so-called. technique of “cross-hatching”. The laryngeal endoscopic surgery is used micromanipulator, if we are to remove a large tumor of the larynx much better to use the guide laryngeal.

CONCLUSIONS

The KTP laser is an important tool in the operational procedures in otolaryngology in large part due to the high activity and its complexity hemostatycznemu assistant. Become familiar with the operation of the laser and improvement of surgical techniques allows patients to propose a modern surgical procedures. Improves the possibility of radical treatment of tumors of the larynx endoscopic method.

Local injection of bevacizumab (Avastin) and angiolytic KTP laser treatment of recurrent respiratory papillomatosis of the vocal folds: a prospective study

OBJECTIVES

Photoangiolytic laser treatment of recurrent respiratory papillomatosis (RRP) is effective, but does not reliably prevent recurrence. Therefore, sublesional injections of the antiangiogenic agent bevacizumab (Avastin) were given to assess the adjunctive effect on disease recurrence. Since bevacizumab is a new therapeutic modality for RRP, there were also primary safety objectives to determine whether there was a pegative impact on the voice and whether there were local or systemic complications.

METHODS

A prospective open-label investigation was conducted in 20 adult patients with bilateral vocal fold RRP. The patients underwent planned 532-nm pulsed KTP laser photoangiolysis of bilateral glottal disease 4 times with an approximately 6-week interval between procedures. At each planned laser procedure, the vocal fold that on initial presentation had a greater volume of disease also underwent 4 serial sublesional bevacizumab injections (7.5 to 12.5 mg in 0.3 to 0.5 mL). A sham injection with saline solution was administered to the other vocal fold as a control. Disease resolution was compared between subjects' vocal folds, and objective measures of vocal function (acoustic, aerodynamic), as well as patients' self-assessments of vocal function (Voice-Related Quality of Life survey), were obtained.

RESULTS

All 20 patients completed the study, and there were no local or systemic complications. After 4 injections, 3 of the 20 patients had no discernible disease in either vocal fold. Of the remaining 17 subjects, 16 had less disease in the bevacizumab-treated vocal fold despite starting with more disease. Only 1 of the 17 had more disease in the bevacizumab-treated vocal fold after 4 injections. Moreover, 7 of the 20 patients (35%) did not require a laser procedure in the vocal fold that had received 4 bevacizumab injections, as compared with 3 of the 20 vocal folds (15%) that were treated with laser alone. All of the vocal function measures displayed statistically significant posttreatment improvements, except for average fundamental frequency in the 3 female patients, in whom it fell below the normal range.

CONCLUSIONS

This prospective investigation provided evidence that bevacizumab injections enhanced KTP laser treatment of glottal papillomatosis without systemic or local complications. Coupling the antiangiogenesis agent bevacizumab with KTP laser photoangiolysis is conceptually synergistic and scientifically promising since the mechanisms of action are complementary.

532-nanometer potassium titanyl phosphate (KTP) laser-induced expression of selective matrix metalloproteinases (MMP) in the rat larynx

OBJECTIVE/HYPOTHESIS

The 532-nm KTP laser is clinically useful to induce benign vocal fold lesion regression without a fibrotic response. Previously, we described an in vivo model for KTP-induced injury in the rat larynx. This study uses this model to correlate the KTP-induced histologic and biochemical changes with the absence of long-term vocal fold fibrosis seen in clinical scenarios.

STUDY DESIGN

In vivo.

METHODS

Unilateral vocal fold injury was induced via KTP laser at 10W (20mS pulse width) as described by our laboratory previously. Animals were subjected to serial endoscopic imaging from postoperative days 1 through 3. Animals were euthanized at 1 day, 4 weeks, and 12 weeks posttreatment and subjected to histologic analyses via hematoxylin and eosin and trichrome staining, as well as RT-PCR analyses for MMP-3, 9, transforming growth factor-beta (TGF-β), and COX-2 mRNA expression. Uninjured vocal folds were used as controls.

RESULTS

Our study revealed gross healing of the vocal fold mucosa by 3 days posttreatment, and an immediate, moderate inflammatory infiltrate with no subsequent ultrastructural changes on histology. MMP-3 and COX-2 expression increased transiently, although no changes were seen in expression of MMP-9, an MMP involved in extracellular matrix remodeling, or TGF-β, a profibrotic cytokine.

CONCLUSIONS

These data suggest that the KTP laser induces a modest inflammatory response, selective MMP expression, and no long-term fibrotic processes in a clinically relevant simulation.

Transoral laser microsurgery for laryngeal cancer: a primer and review of laser dosimetry

Transoral laser microsurgery (TLM) is an emerging technique for the management of laryngeal and other head and neck malignancies. It is increasingly being used in place of traditional open surgery because of lower morbidity and improved organ preservation. Since the surgery is performed from the inside working outward as opposed to working from the outside in, there is less damage to the supporting structures that lie external to the tumor. Coupling the laser to a micromanipulator and a microscope allows precise tissue cutting and hemostasis; thereby improving visualization and precise ablation. The basic approach and principles of performing TLM, the devices currently in use, and the associated dosimetry parameters will be discussed. The benefits of using TLM over conventional surgery, common complications and the different settings used depending on the location of the tumor will also be discussed. Although the CO₂ laser is the most versatile and the best-suited laser for TLM applications, a variety of lasers and different parameters are used in the treatment of laryngeal cancer. Improved instrumentation has lead to an increased utilization of TLM by head and neck cancer surgeons and has resulted in improved outcomes. Laser energy levels and spot size are adjusted to vary the precision of cutting and amount of hemostasis obtained.

Protective effect of autophagy in laser-induced glioma cell death in vitro

BACKGROUND AND OBJECTIVE

Laser phototherapy could be potentially used for cancer treatment, but the mechanisms of laser-induced cell death are not completely understood. Autophagy is the process in which the damaged cellular proteins and organelles are engulfed by and destroyed in acidified multiple-membrane vesicles. The aim of the present study was to investigate the role of autophagy in laser-induced tumor cell death in vitro.

STUDY DESIGN/MATERIALS AND METHODS

The monolayers of U251 human glioma tumor cells were exposed to 532 nm laser light from a single mode frequency-doubled Nd-YVO4 laser. A flattened Gaussian radial profile of laser beam (0.5-4 W) was used to uniformly illuminate entire colony of cells for various amounts of time (15-120 seconds) in the absence of cell culture medium. The cells were grown for 24 hours and the cell viability was determined by crystal violet or MTT assay. The presence of autophagy was assessed after 16 hours by fluorescence microscopy/flow cytometric analysis of acridine orange-stained autophagolysosomes and Western blot analysis of the autophagosome-associated LC3-II protein. The concentration of the principal pro-autophagic protein beclin-1 was determined after 6 hours by cell-based ELISA.

RESULTS

The intracytoplasmic accumulation of autophagic vesicles, increase in LC3-II and up-regulation of beclin-1 expression were clearly observed under irradiation conditions that caused approximately 50% cytotoxicity. Post-irradiation addition of three different autophagy inhibitors (bafilomycin A1, chloroquine, or wortmannin) further increased the laser-induced cytotoxicity, without affecting non-irradiated cells.

CONCLUSIONS

These data indicate that beclin-1-dependent induction of autophagy can protect glioma cells from laser-mediated cytotoxicity.

Voice production mechanisms following phonosurgical treatment of early glottic cancer

OBJECTIVES

Although near-normal conversational voices can be achieved with the phonosurgical management of early glottic cancer, there are still acoustic and aerodynamic deficits in vocal function that must be better understood to help further optimize phonosurgical interventions. Stroboscopic assessment is inadequate for this purpose.

METHODS

A newly developed color high-speed videoendoscopy (HSV) system that included time-synchronized recordings of the acoustic signal was used to perform a detailed examination of voice production mechanisms in 14 subjects. Digital image processing techniques were used to quantify glottal phonatory function and to delineate relationships between vocal fold vibratory properties and acoustic perturbation measures.

RESULTS

The results for multiple measurements of vibratory asymmetry showed that 31% to 62% of subjects displayed higher-than-normal average values, whereas the mean values for glottal closure duration (open quotient) and periodicity of vibration fell within normal limits. The average HSV-based measures did not correlate significantly with the acoustic perturbation measures, but moderate correlations were exhibited between the acoustic measures and the SDs of the HSV-based parameters.

CONCLUSIONS

The use of simultaneous, time-synchronized HSV and acoustic recordings can provide new insights into postoperative voice production mechanisms that cannot be obtained with stroboscopic assessment.

Microlaryngoscopic and office-based injection of bevacizumab (Avastin) to enhance 532-nm pulsed KTP laser treatment of glottal papillomatosis

OBJECTIVES

Photoangiolytic lasers effectively treat glottal papillomatosis, but do not reliably prevent recurrence. Therefore, sublesional injections of the antiangiogenic agent bevacizumab (Avastin) were given to assess the effect on disease recurrence and phonatory function.

METHODS

A retrospective investigation was done in a pilot group of 10 adult patients with bilateral glottal papillomatosis who had prior angiolytic laser treatment with established patterns of recurrence. The patients underwent 5 bevacizumab injections (5 to 10 mg) into the diseased vocal folds along with 532-nm pulsed KTP laser photoangiolysis treatments 4 to 6 weeks apart. Their disease resolution was compared to findings from prior laser treatment alone, and objective measures of vocal function (acoustic, aerodynamic, Voice-Related Quality of Life survey) were obtained.

RESULTS

All 10 patients had a greater than 90% reduction in recurrence. Four of the 10 had resolution. Four of the 10 have limited recurrent or persistent disease, receive injections of bevacizumab at 8- to 12-week intervals, and have not required laser treatment. Two of the 10 have ongoing periodic office-based KTP laser treatment along with bevacizumab injections. No patient has required microlaryngeal surgery with general anesthesia, and all 10 have had substantial improvement in vocal function.

CONCLUSIONS

This pilot investigation provides preliminary evidence that bevacizumab injections enhance photoangiolytic laser treatment of glottal papillomatosis while enhancing phonatory function. Coupling an antiangiogenesis agent with pulsed KTP laser photoangiolysis is conceptually promising, since the mechanisms of action are complementary.

Value and utility of 532 nanometre pulsed potassium-titanyl-phosphate laser in endoscopic laryngeal surgery

Objectives:

Recently, the 532 nm pulsed potassium-titanyl-phosphate laser has emerged as an effective angiolytic laser for treating mucosal lesions of the larynx in the operating theatre and clinic. We sought to assess the current impact of potassium-titanyl-phosphate laser on our laryngeal surgery practice.

Study design:

Retrospective review of 710 patients undergoing endoscopic laryngeal surgery over a one-year period.

Methods:

Medical records of the endoscopic laryngeal procedures were reviewed; 386/710 had been performed in the clinic and 324/710 in the operating theatre under general anaesthesia. Indications for the procedures were classified by pathology.

Results:

Pulsed potassium-titanyl-phosphate laser was used in 209/386 clinic procedures. The indications for these procedures were: dysplasia (114/209 procedures), papillomatosis (89/209), varices or ectasia (three of 209), and ‘other’ (three of 209). Pulsed potassium-titanyl-phosphate laser was used in 178/324 operating theatre endoscopic laryngeal procedures. The indications for these procedures were: cancer (54/178 procedures), dysplasia (52/178), papillomatosis (38/178), varices or ectasia (13/178), polyps (six of 178), nodules (six of 178), stenosis (five of 178), granulation (three of 178), and amyloid (one of 178).

Conclusions:

Due to its versatility, the 532 nm pulsed potassium-titanyl-phosphate laser is our most commonly utilised instrument for performing endoscopic laryngeal surgery.