Ultrastructural evaluation of 585-nm pulsed-dye laser-treated glottal dysplasia

Indications, Efficacy, Safety, and Clinical Outcomes of 585 nm Pulsed Dye Laser in Non-Malignant Laryngeal Lesions: A Systematic Review

The objective of this manuscript was to review the indications, efficacy, and safety of a 585 nm pulsed dye laser (PDL) in non-malignant laryngeal lesions. Following the PRISMA statement recommendations, three independent authors searched for articles published in PubMed/MEDLINE, the Cochrane Library, Google Scholar, Scielo, and Web of Science. A bias analysis was performed following NICE guidance tools. From the 506 identified publications, 19 observational studies met the inclusion criteria. The PDL improves vocal quality objectively and subjectively in vascular lesions (p < 0.005) and improves vocal quality in patients with dysplasia/leukoplasia without changing the natural history of the disease compared to other treatments. Reinke's edema and granulomas require an average of 1.5 PDL sessions for resolution. Treatment of recurrent respiratory papillomatosis requires multiple sessions, with complete remission achieved in 50-70% of patients. Regardless of the lesion, the tolerance of the procedure under local anesthesia is exceptional (84-97%), and the results in terms of regression and vocal quality are promising. The complication rate is minimal, and the procedure does not interfere with other treatment alternatives. There is no consensus on laser settings. The lack of consistent use in evaluating vocal outcomes, whether objective or subjective, prevents the comparability between studies. The 585 nm pulsed dye laser appears to be an effective and safe therapeutic option in patients with non-malignant laryngeal pathology. Future controlled studies are needed to compare the 585 nm pulsed dye laser with other lasers or cold instrument procedures.

Optical Fiber Coupling System for Steerable Endoscopic Instruments

In this paper, we present an optical coupling system that couples light from an Endostat fiber in a commercial laser surgical system into a smaller multimode fiber, in order to enable endoscopic probe steering in a tightly confined space. Unlike the Endostat fibers, which have a minimum bending radius of 12 mm due to the large diameter, our work allows the laser to be delivered by smaller fibers that can be readily bent at a 6-mm bending radius by a distal steerable mechanism. Such a readily achievable sharp bending facilitates the surgical laser to access hard-to-reach anatomies. We experimentally achieved an optical power coupling efficiency of ≈ 50%. Tissue ablation experiments were performed to prove the feasibility and potential of our light coupling system in clinical laser surgeries, as well as other optical fiber-based endoscopic medical devices.Clinical Relevance- Optical fibers are commonly used in laser-based surgical systems. The optical coupling system in this paper enables the laser to be delivered by small fibers, helps realize the fiber bending and steering, and hence allows the laser treatments of previous inaccessible anatomies.

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

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.

Treatment of Hemorrhagic Vocal Polyps by Pulsed Dye Laser-Assisted Laryngomicrosurgery

Objective. Conventional surgical techniques of laryngomicrosurgery (LMS) on hemorrhagic vocal polyps are often difficult due to obscuration of the surgical field by inadvertent bleeding from the lesion, and there are often significant amounts of mucosal epithelium loss. Here, we introduce our surgical technique using pulsed dye laser (PDL), which can effectively resect the polyp with vocal fold mucosa preservation. Methods. Patients who were diagnosed with hemorrhagic vocal polyp and who were surgically managed using PDL from March 2013 to October 2014 were retrospectively reviewed. Preoperative and postoperative clinical outcomes and surgical findings were evaluated. Results. A total of 39 patients were treated with PDL-assisted enucleation LMS. The average age was 43.7 years (range 20–73), and there were 20 males and 19 females (17 professional voice users). In all cases, the hemorrhagic polyp was successfully enucleated after application of PDL, thereby preserving the overlying epithelium. Postoperative voice outcomes were favorable with clear preservation of the vocal fold mucosal wave. Conclusion. PDL-assisted enucleation LMS for the treatment of hemorrhagic vocal polyps can be a safe and effective surgical technique. It can be considered a promising treatment option for hemorrhagic vocal polyps.

Quantitative study of vibrational symmetry of injured vocal folds via digital kymography in excised canine larynges

PURPOSE

Digital kymography and vocal fold curve fitting are blended with detailed symmetry analysis of kymograms to provide a comprehensive characterization of the vibratory properties of injured vocal folds.

METHOD

Vocal fold vibration of 12 excised canine larynges was recorded under uninjured, unilaterally injured, and bilaterally injured conditions. Kymograms were created at 25%, 50%, and 75% of the vocal fold length, and vibratory parameters were compared quantitatively among conditions and were studied with respect to right-left and anterior-posterior symmetries.

RESULTS

Anterior-posterior amplitude asymmetry was found in the bilateral condition. The unilateral condition showed significant right-left amplitude asymmetry, and it showed the lowest right-left phase symmetry among the conditions. In condition comparisons, vertical phase difference did not show significant differences among conditions, whereas amplitudes were significantly different among conditions at all line scan positions and most vocal fold lips. Significant differences in frequency were found among the conditions at all 4 vocal fold lips, with the bilateral condition exhibiting the greatest frequency.

CONCLUSION

Digital kymography and curve fitting provide detailed information about the vibratory behavior of injured vocal folds. Awareness of vibratory properties associated with vocal fold injury may aid in diagnosis, and the quantitative abilities of digital kymography may allow for objective treatment selection.

Pulse dye and other laser treatments for vocal scar

PURPOSE OF REVIEW

Vocal fold scar is a challenging clinical problem, resulting in a spectrum of voice-related complaints. While there are a variety of treatment options available, it is rare to obtain outcomes similar to the perfectly normal voice. The pulsed dye and other lasers are an emerging treatment option for cutaneous scar and have shown promise for the treatment of vocal fold scarring. The purpose of this review is to summarize the theory, and describe clinical outcomes from both cutaneous and vocal fold scarring treated with lasers.

RECENT FINDINGS

There are a growing number of papers in the literature substantiating the use of pulsed dye and other lasers used to treat cutaneous scars. Some experimental models describe potential mechanisms of laser effect, which include the development of a sub-basement membrane cleavage plane, as well as up-regulation of proteins which may actively modulate continued fibrosis. One prospective pilot study of 11 patients with vocal fold scarring treated with the pulsed dye laser has also shown statistically significant improvement in subjective and objective voice measures, as well as laryngeal stroboscopy findings after treatment.

SUMMARY

The pulsed dye and other lasers have shown effectiveness and potential in treating cutaneous and vocal scarring.

Pulsed dye laser-induced inflammatory response and extracellular matrix turnover in rat vocal folds and vocal fold fibroblasts

BACKGROUND AND OBJECTIVES

Disruption of the vocal fold extracellular matrix (ECM) can induce a profound and refractory dysphonia. Pulsed dye laser (PDL) irradiation has shown early promise as a treatment modality for disordered ECM in patients with chronic vocal fold scar; however, there are limited data addressing the mechanism by which this laser energy might induce cellular and extracellular changes in vocal fold tissues. In this study, we examined the inflammatory and ECM modulating effects of PDL irradiation on normal vocal fold tissues and cultured vocal fold fibroblasts (VFFs).

STUDY DESIGN/MATERIALS AND METHODS

We evaluated the effects of 585 nm PDL irradiation on inflammatory cytokine and collagen/collagenase gene transcription in normal rat vocal folds in vivo (3-168 hours following delivery of approximately 39.46 J/cm(2) fluence) and VFFs in vitro (3-72 hours following delivery of 4.82 or 9.64 J/cm(2) fluence). We also examined morphological vocal fold tissue changes 3 hours, 1 week, and 1 month post-irradiation.

RESULTS

PDL irradiation altered inflammatory cytokine and procollagen/collagenase expression at the transcript level, both in vitro and in vivo. Additionally, PDL irradiation induced an inflammatory repair process in vivo that was completed by 1 month with preservation of normal tissue morphology.

CONCLUSIONS

PDL irradiation can modulate ECM turnover in phenotypically normal vocal folds. Additional work is required to determine if these findings extend to disordered ECM, such as is seen in vocal fold scar. Lasers Surg. Med. 41:585-594, 2009. (c) 2009 Wiley-Liss, Inc.

Use of lasers in laryngeal surgery

Lasers are a relatively recent addition to laryngeal surgery. Since their invention, laser use and applications have expanded rapidly. In this article, we discuss the benefits and disadvantages of lasers for different procedures, as well as ways to overcome commonly faced clinical problems. The use of lasers in surgery has offered a time- and cost-efficient alternative to cold surgical techniques, and has been used in the treatment of numerous laryngeal pathologies, including stenoses, recurrent respiratory papillomatosis, leukoplakia, nodules, malignant laryngeal disease, and polypoid degeneration (Reinke's edema). However, lasers can incur adjacent tissue damage and vocal fold scarring. These problems can be minimized through understanding the mechanisms by which lasers function and correctly manipulating the parameters under a surgeon's control. By varying fluence, power density, and pulsation, tissue damage can be decreased and lasers can be used with greater confidence. The various types of lasers and their applications to the treatment of specific pathologies are reviewed with the intention of helping surgeons select the best tool for a given procedure. Recent applications of lasers to treat benign laryngeal lesions and severe laryngomalacia demonstrate that additional research must be conducted to realize the full potential of this surgical tool.