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KTP Laser for the Larynx

last modified on: Thu, 12/07/2023 - 10:12

return to: Laser Surgery Protocols

see also: KTP Laser for RRP local anesthesia case exampleLaryngeal papilloma (RRP) treatment in clinic with KTP laser videoKTP (potassium-titanyl-phosphate) laser in office treatment of vocal fold polypsSuperior Laryngeal Nerve Blocks Instruction VideoGlossopharyngeal nerve block (gag reflex, transoral vocal cord surgery)KTP laser for papilloma microdirect laryngoscopyRecurrent Respiratory Papillomatosis (RRP) - General InformationMicrodirect Laryngoscopy case example

(Wang C-T et al 2013)

KTP = potassium titanyl phosphate 532 nm

PDL = pulsed-dye laser 585 nm

close to absorbance peak of hemoglobin - selective angiolysis and photocoagulation of vascular lesions with minimal thermal injury to the lamina propria

Procedure: (ref 9)- nasal decongestion/anesthesia; spray 2% lidocaine to pharynx, tonsils, vallecula. Drip 5 cc of lidcaine (2% on laryngeal introitus)

0.6 mm KTP laser fiber passed through working channel of flex laryngoscopes photo coagulate polyp:

settings = 6-8 W per pulse with pulse width of 15 to 25 milliseconds and a 2-Hz repetition rate (ref 11)

endpoint = blanching or darkening of the lesion

After initial report of KTP in the larynx (ref 17) later research showed that pulsed KTP laser energy better photoangiolytic effect than short-duration continuous laser energy. Rupture of vessel walls can be prevented by increasing pulse width and fiber-to tissue distance and decreasing laser energy. (ref 21)

(Young VN et al 2015)

KTP - initial indications were vascular lesions - now expanded to include nonvascular photraumatic less of the vocal folds including leukoplakia, papilloma polyps granuloma and selected carcinoma.

Methods with KTP - isolated angiolysis, on ablative and frank tissue ablative with or without tissue removal. 

Problems: user-dependent variability in total energy delivered and laser parameters of wattage, pulse width, and pulses per second.; KTP uses a fiber delivery system which contains an inherent variability in laser fluence

Fluence: "energy delivered per cross-sectional surface area"

is largely determined by fiber-to tissue distance - and is not always reliably controlled.

These authors therefore classified 'immediate end-tissue effects' to classify treatment - incorporating both intrinsic laser parameters and fluency to standardize procedure goals:

This study provides a detailed description of KTP laser treatment, including laser settings, energy delivery duration of traumata and systematic treatment effect - to serve as a reference

The overall energy delivered depends on fiber to tissue distance and use of contact or non contact modes as well as tissue characteristics - in addition to laser parameters and total energy delivered - some of the variability in fluency can be accounted for.

they found it is possible to cause more visible tissue damage with a total lower energy and vice versa -likely contingent on fiber to tissue distance and watts per pulse

suggest: KTP 2 or 3 efect and less than 200 J of total energy most efficacious for this group with 

Suggested settings for Reinke's edema:

15-35 watts per pulse

15-ms pulse width

2 pulses per second

up to 200 J delivered in non-ablative manner

"Pulsed KTP laser setting varied based on surgeon judgment; total energy delivered in joules (J) was recorded for the entire procedure"

KTP Laser setting


Power settings

15 - 35 watts

Pulse width


Temporal distribution

2-pulse-per second

Average amount of

KTP laser energy

per procedure

average =157 J (6- 640 J)

median of 110 J

Lasing time

average 0.37 seconds (0.1 -0.9 seconds

median 0.35 seconds


Treatment Classification

KTP (Potassium titanyl phosphate)

Assessment of Immediate Tissue Effect

(Mallur et all 2014)


Noncontact with angiolysis


Noncontact mucosal blanching


Noncontact epithelium disruption


Contact with epithelial ablation without tissue removal


Contact with epithelial ablation with subsequent tissue removal

KTP wavelength of 532 nm (hemoglobin absorbs more strongly than the 585 nm wavelength of PDL(Yan et al 2008)

pulsed KTP laser - wider pulse than the KTP - able to spread laser energy over a longer time - offering slower heating and more even coalition than PDL

Use of a higher power and shorter time pulse results in less tissue damage than a lower power for a longer period of time. 

"Skip technique": spacing out laser impact (even for a continuous incision) decreases thermal damage by allowing time for the tissue to cool between impacts.

Note the importance in keep the laser fiber clean and appropriately "cleaved" (cut) at its tip so as to optimize light dispersion - discussed in detail by Tracy et al (Tracy 2019)

(Janda et al 2004)

Use of Nd:YAG laser (wavelength 1064 nm) for 'good coagulation and hemostatic capabilities 

(Burns 2007)

Suggested setting for KTP laser for RRP under general anesthesia

5.25-7.5 Joules / pulse

15 ms pulse width

2 Hz repetition rate

0.4 mm fiber

~ 20-80 J/cm2 fluence

Topical anesthesia

Administration of 4% lidocaine to the mucosa of the base of tongue, supraglottis, and glottis using one of several approaches (trans-nasal through working port of endoscope / trans-oral with curved applicator / trans-tracheal)

Recommend capping dose at 5 cc (200mg of 4% lidocaine) - but dose may vary and calculation by weight can use a maximum safe dose of 3 mg/kg (Wang 2013)

see also: Maximum Recommended Doses and Duration of Local Anesthetics


Yan Y, Olszewski AE, Hoffman MR, Zhuang P, Ford CN, Sailey SH, and Jiang JJ: Use of Lasers in Laryngeal Surgery Journal of Voice, vol 24,No.1. pp 102-109

Wang C-T, Huang T-W, Liao L-J, Lo W-C, Lai M-S and Chng P-W: Office-Based Potassium Titanyl Phosphate Laser-Assisted Endoscopic Vocal Polypectomy. Jama Otolarygnol Head Neck Surg/ Vol 139 (No.6), June 2013

Young VN, Mallur PS, Wong AW, Mandal R, Staltari GV, Gartner-Schmidt J, and Rosen CA: Analysis of Potassium Titanyl Phosphate Laser Settings and Voice outcomes int he Treatment of Reinke's Edema  Annals of Otology Rhinology and Larygnolgoy 2015. Vol 124(3) 216-220

Mallur PS, Johns MM, Amin MR, Rosen C Proposed classification system for reporting 532-nm pulsed potassium titanyl phosphate laser treatment effects on vocal fold lesions. Laryngoscop 2014;124(5):11701175

Zeitels SM: Glottic Cancer: A Metamorphosing Disease. Annals of Otology, Rhinology & Laryngology 1-5 DOI:10.1177/0003489415619177

Janda P, Leunig A, Sroka R, Betz C and Rasp G: Preliminary report of endolarygneal and endotracheal laser surgery of juvenile-onset recurrent repoiratory papillomatosis by Nd:YAG laser and a new fiber guidance instrument

Burns JA, Zeitels SM, Akst LM, Broadhurst MS, Hillman RE and Anderson R: 532 nm Pulsed Potassium-Titanyl-Phosphate Laser Treatment of Laryngeal Papillomatosis under General Anesthesia. Laryngoscope 117:1500-1504

Wang SX, Simpson CB. Anesthesia for office procedures. Otolaryngol Clin North Am. 2013;46(1):13-9

Journal of VoiceVolume 26, Issue 6, November 2012, Pages 806-810Multi-Institutional Experience With the In-Office Potassium Titanyl Phosphate Laser for Laryngeal Lesions  [acknowledges problems with determining fluence]

Koszewski IJ1, Hoffman MR1, Young WG1, Lai YT1, Dailey SH2. Otolaryngol Head Neck Surg. 2015 Jun;152(6):1075-81. Office-Based Photoangiolytic Laser Treatment of Reinke's Edema: Safety and Voice Outcomes.

Lauren F. Tracy, MD ; James B. Kobler, PhD; Jarrad H. Van Stan, PhD; James A. Burns, MD, FACS:  Carbon Debris and Fiber Cleaving: Effects on Potassium-Titanyl-Phosphate Laser Energy and Chorioallantoic Membrane Model Vessel CoagulationLaryngoscope, 129:2244–2248, 2019

Coughlan CA, Verma SP. Evaluating the effects of a 532-nm fiber-based KTP laser on transoral laser surgery supplies. Otolaryngol Head Neck Surg. 2013 Nov;149(5):739-44. doi: 10.1177/0194599813505423. Epub 2013 Sep 20. PMID: 24057676.