Laser tumor treatment in oral and maxillofacial surgery

Potassium titanyl phosphate laser resection of tongue T1/T2 squamous cell carcinoma - a cross-sectional study of quality of life and nutritional outcomes

INTRODUCTION

Increasing emphasis has been placed on measurement of quality of life (QOL) as a central criterion for assessment of success of any medical treatment. The aim of our study was to assess the nutritional and quality of life of patient-reported outcomes among patients who have undergone laser resection of tongue cancer.

MATERIALS AND METHODS

A cross-sectional study was undertaken of patients treated with KTP laser resection of T1/T2 tongue squamous cell carcinoma (SCC) between 2011-2019. University of Washington Quality of life 4 questionnaire (UW-QOL) and the abridged scored patient-generated subjective global assessment (AB PG-SGA) were used. Scores were correlated to analyse the QOL and nutritional status.

RESULTS

20 patients participated and were categorised into three groups based on AB PG-SGA score. The physical and social-emotional QOL scores were higher for patients who had a better nutritional status. There was a linear negative correlation between the AB PG-SGA score, physical and social-emotional domains of the QOL. No association was found between histopathological differentiation, neck dissection surgeries and the AB PG-SGA score.

CONCLUSIONS

The use of the KTP laser to excise tongue T1 and T2 SCC yields acceptable results in terms of QOL and patient-reported nutritional outcomes. There is a significant trend identifying that as a patient's nutritional status improves quality of life is enhanced and vice versa. The QOL and the nutritional status of patients were not affected by the different histopathological grades of SCC or whether they had undergone a neck dissection or not.

KTP 532 Laser Assisted Surgery for Oral Cavity Malignancy-A Retrospective Study

Aims and Objective

To determine the effectiveness of KTP 532 in surgically treating early and early advanced oral malignancy with no surgical reconstruction of primary site.

Materials and methods

It is a retrospective study of 67 cases operated between 2000 to 2013 including T1, T2 and Early T3 cases, approved by ethical committee. All the cases underwent Laser assisted excision of tumour with or without Neck Dissection or Adjuvant Radiotherapy. Age of the cases varied from 20 to 80 years with mean age of 49 years. 47 cases were males and 20 were females. 26 cases in the study had neck nodes clinically whereas 41 cases had N0 status. Neck dissection was done (SOND or MRND) in 61 cases. In 6 cases (N0) no neck dissection was done.

Results

61 cases had no loco-regional residual disease on their last follow up. Six cases had loco-regional recurrence within 6 months and salvage surgery was done. The overall mean survival was 81 months (92, 82 and 71 months in Stage I, II,III respectively). 3 year disease free survival rate was 91% as calculated using Kaplan- Meier Scale. In all these cases tumour was excised with KTP 532 laser and no reconstruction was done. Wound was allowed to heal with secondary intention.

Conclusion

Laser assisted excision of oral malignancy is an alternative to conventional treatment with more precision, less morbidity, shorter hospital stay and better functional outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12070-022-03214-x.

Towards OCT-Guided Endoscopic Laser Surgery-A Review

Optical Coherence Tomography (OCT) is an optical imaging technology occupying a unique position in the resolution vs. imaging depth spectrum. It is already well established in the field of ophthalmology, and its application in other fields of medicine is growing. This is motivated by the fact that OCT is a real-time sensing technology with high sensitivity to precancerous lesions in epithelial tissues, which can be exploited to provide valuable information to clinicians. In the prospective case of OCT-guided endoscopic laser surgery, these real-time data will be used to assist surgeons in challenging endoscopic procedures in which high-power lasers are used to eradicate diseases. The combination of OCT and laser is expected to enhance the detection of tumors, the identification of tumor margins, and ensure total disease eradication while avoiding damage to healthy tissue and critical anatomical structures. Therefore, OCT-guided endoscopic laser surgery is an important nascent research area. This paper aims to contribute to this field with a comprehensive review of state-of-the-art technologies that may be exploited as the building blocks for achieving such a system. The paper begins with a review of the principles and technical details of endoscopic OCT, highlighting challenges and proposed solutions. Then, once the state of the art of the base imaging technology is outlined, the new OCT-guided endoscopic laser surgery frontier is reviewed. Finally, the paper concludes with a discussion on the constraints, benefits and open challenges associated with this new type of surgical technology.

Lasers in Maxillofacial Surgery - Review of Literature

The availability of different wavelengths of lasers has created a surgical panacea in the last decade and laser technology has become the standard of care for many oral and maxillofacial surgical procedures. In this article, based on literature search, we have reviewed the usage of laser in maxillofacial surgery based on the current evidence available on laser-assisted maxillofacial surgery, in PubMed database.

Excision of Different Oral Benign Exophytic Lesions With a Diode Laser: A Clinical Case Series

Introduction: Lasers are becoming the standard of care for many dental procedures, and are being introduced as a high-tech instrument. They are also becoming more routine in dentistry through the advent of office-based lasers, which are also simple to use within the oral cavity. Many studies have shown the competencies of laser technology for the management of benign oral lesions as these techniques allow for painless and bloodless oral surgery. Cases Report: Nine patients attending the Department of oral and maxillofacial Disease, Shahid Beheshti University of Medical Sciences, Tehran, Iran, underwent laser outpatient procedures for the surgical removal of a wide range of benign oral lesions. Regarding the history, present illnesses and clinical figures of all reported cases, the clinician ensured that the lesions were benign and after taking informed consent from every patient, he did complete the excision of lesions with diode lasers. Following the injection of local anesthesia, an 810 nm diode laser was applied for the excisional biopsy of oral lesions. The specimens were sent for histopathological evaluations and the patients were assessed on intraoperative and postoperative complications. The patients were followed up for postoperative complications at one week and 2 weeks post-treatment. Conclusions: According to our findings, a diode laser can be a choice for the outpatient treatment of oral mucosal benign lesions as this technique provides painless and almost bloodless treatment.

A review on numerical modeling for magnetic nanoparticle hyperthermia: Progress and challenges

Recent progress in nanotechnology has advanced the development of magnetic nanoparticle (MNP) hyperthermia as a potential therapeutic platform for treating diseases. Due to the challenges in reliably predicting the spatiotemporal distribution of temperature in the living tissue during the therapy of MNP hyperthermia, critical for ensuring the safety as well as efficacy of the therapy, the development of effective and reliable numerical models is warranted. This article provides a comprehensive review on the various mathematical methods for determining specific loss power (SLP), a parameter used to quantify the heat generation capability of MNPs, as well as bio-heat models for predicting heat transfer phenomena and temperature distribution in living tissue upon the application of MNP hyperthermia. This article also discusses potential applications of the bio-heat models of MNP hyperthermia for therapeutic purposes, particularly for cancer treatment, along with their limitations that could be overcome.

Comparison of Er:YAG and Er,Cr:YSGG Laser in the Treatment of Oral Leukoplakia Lesions Refractory to the Local Retinoid Therapy

Objective: The aim of this study was to compare the efficacy of Er:YAG and Er,Cr:YSGG laser in the treatment of oral leukoplakia refractory to conventional retinoid therapy. Materials and methods: The study sample consisted of 54 patients (16 men and 38 women) who were histopathologically diagnosed with oral leukoplakia that was refractory to conventional retinoid therapy. Patients were randomly allocated into two groups according to the type of the laser used for treatment of oral leukoplakia: Group 1. Er:YAG laser; Group 2. Er,Cr:YSGG laser. Patients were recalled at 6 months and 1 year after treatment to evaluate possible recurrence and assess the patients' postoperative quality of life. Results: After initial ablation, the degree of residual lesion was significantly greater in the Er:YAG laser group (74.1%), compared with the Er,Cr:YSGG group (18.5%) (p = 0.0001). Six months and 1 year after the second ablation, there was no lesion recurrence in either laser group. Fourteen days after the initial ablation, the visual analog scale (VAS) pain rating and the total oral health impact profile score fell significantly in both groups (p < 0.0001). However, in the Er,Cr:YSGG laser group, the average value of the VAS rating was significantly lower than in the Er:YAG laser group (p = 0.039). Conclusions: The Er:YAG and Er,Cr:YSGG lasers showed similar efficacy in the treatment of oral leukoplakia and resulted in full postoperative recovery without recurrence after 1 year of follow-up.

Noncontact monitoring of incision depth in laser surgery with air-coupled ultrasound transducers

Lack of haptic feedback during laser surgery makes it difficult to control the incision depth, leading to high risk of undesired tissue damage. Here, we present a new feedback sensing method that accomplishes noncontact real-time monitoring of laser ablation procedures by detecting shock waves emanating from the ablation spot with air-coupled transducers. Experiments in soft and hard tissue samples attained high reproducibility in real-time depth estimation of the laser-induced cuts. The advantages derived from the noncontact nature of the suggested monitoring approach are expected to advance the general applicability of laser-based surgeries.

Real-time monitoring of incision profile during laser surgery using shock wave detection

Lack of sensory feedback during laser surgery prevents surgeons from discerning the exact location of the incision, which increases duration and complexity of the treatment. In this study we demonstrate a new method for monitoring of laser ablation procedures. Real-time tracking of the exact three dimensional (3D) lesion profile is accomplished by detection of shock waves emanating from the ablation spot and subsequent reconstruction of the incision location using time-of-flight data obtained from multiple acoustic detectors. Here, incisions of up to 9 mm in depth, created by pulsed laser ablation of fresh bovine tissue samples, were successfully monitored in real time. It was further observed that, by utilizing as little as 12 detection elements, the incision profile can be characterized with accuracy below 0.5 mm in all three dimensions and in good agreement with histological examinations. The proposed method holds therefore promise for delivering high precision real-time feedback during laser surgeries.

Gold nanoshell/polysaccharide nanofilm for controlled laser-assisted tissue thermal ablation

We report on the fabrication and characterization of a freestanding ultrathin, mucoadhesive gold nanoshell/polysaccharide multilayer nanocomposite (thermonanofilm, TNF), that can be used for controlled photothermal ablation of tissues through irradiation with near-infrared radiation (NIR) laser. The aim of this work is to provide a new strategy to precisely control particle concentration during photothermalization of cancerous lesions, since unpredictable and aspecific biodistributions still remains the central issue of inorganic nanoparticle-assisted photothermal ablation. Gold nanoshell encapsulation in polysaccharide matrix is achieved by drop casting deposition method combined with spin-assisted layer-by-layer (LbL) assembly. Submicrometric thickness of films ensures tissue adhesion. Basic laser-induced heating functionality has been demonstrated by in vitro TNF-mediated thermal ablation of human neuroblastoma cancer cells, evidenced by irreversible damage to cell membranes and nuclei. Ex vivo localized vaporization and carbonization of animal muscular tissue is also demonstrated by applying TNF onto tissue surface. Thermal distribution in the tissue reaches a steady state in a few seconds, with significant increases in temperature (ΔT > 50) occurring across an 1 mm span, ensuring control of local photothermalization and providing more safety and predictability with respect to traditional laser surgery. A steady-state model of tissue thermalization mediated by TNFs is also introduced, predicting the temperature distribution being known the absorbance of TNFs, the laser power, and the tissue thermal conductivity, thus providing useful guidelines in the development of TNFs. Thermonanofilms can find applications for local photothermal treatment of cancerous lesions and wherever high precision and control of heat treatment is required.

Optoacoustic monitoring of cutting efficiency and thermal damage during laser ablation

Successful laser surgery is characterized by a precise cut and effective hemostasis with minimal collateral thermal damage to the adjacent tissues. Consequently, the surgeon needs to control several parameters, such as power, pulse repetition rate, and velocity of movements. In this study we propose utilizing optoacoustics for providing the necessary real-time feedback of cutting efficiency and collateral thermal damage. Laser ablation was performed on a bovine meat slab using a Q-switched Nd-YAG laser (532 nm, 4 kHz, 18 W). Due to the short pulse duration of 7.6 ns, the same laser has also been used for generation of optoacoustic signals. Both the shockwaves, generated due to tissue removal, as well as the normal optoacoustic responses from the surrounding tissue were detected using a single broadband piezoelectric transducer. It has been observed that the rapid reduction in the shockwave amplitude occurs as more material is being removed, indicating decrease in cutting efficiency, whereas gradual decrease in the optoacoustic signal likely corresponds to coagulation around the ablation crater. Further heating of the surrounding tissue leads to carbonization accompanied by a significant shift in the optoacoustic spectra. Our results hold promise for real-time monitoring of cutting efficiency and collateral thermal damage during laser surgery. In practice, this could eventually facilitate development of automatic cut-off mechanisms that will guarantee an optimal tradeoff between cutting and heating while avoiding severe thermal damage to the surrounding tissues.