Laryngeal Laser Surgery: CO2 Laser Applications

CO2 laser was invented in 1964 by Patel; in the late 1970s Strong and Jako adapted it for laryngeal surgery — birth of modern transoral laser microsurgery (TLM).

Physics: CO2 emits 10.6 µm infrared. Water absorbs strongly at this wavelength — intracellular water instantly boils → cell ruptures → tissue is cut or vaporised. Thermal spread to adjacent tissue is minimal (50-200 µm).

Laser-tissue interaction: spot 100-300 µm, power 1-20 W, milliseconds (continuous wave or pulsed). Defocused (broad area) — vaporisation; focused (narrow point) — cutting. Pulsed mode reduces thermal damage — better histological margins.

Advantages — functional: precise targeting (micron-scale), minimal injury to healthy tissue, vocal fold lamina propria preservation (critical for voice), low postop oedema (short recovery), bleeding control (laser coagulates small vessels), low infection risk (laser self-sterilisation), usually no sutures (autocoagulation).

Advantages — oncological: in early laryngeal cancer the margin is assessable visually + histologically; en bloc resection feasible; conservative surgery (intact vocal fold preserved — voice function); secondary surgery/radiotherapy options remain open.

Advantages — operative: no open surgery, no scar, short hospital stay (usually 1-2 days, sometimes day surgery), tracheotomy rare, rapid recovery.

Disadvantages: high equipment cost (CO2 laser + microscope + micromanipulator + laser-safe accessories), steep learning curve (surgeon experience drives success), anatomic accessibility limits (trismus, small tongue, high tongue base hinder), laser-safety precautions mandatory (fire risk — endotracheal tube, oxygen).

Other lasers: KTP (potassium-titanyl-phosphate) 532 nm green — high haemoglobin absorption → vascular lesions (angioma, polyp) treated effectively; diode laser 980-1064 nm — fibre-deliverable, vascular effect; thulium laser 2000 nm — CO2-like effect via fibre (flexible, hard-to-reach sites); KTP + thulium can be used in office procedures (local anaesthesia). We expand on the clinical framework in our laryngology and voice surgery unit.

TLM (transoral laser microsurgery) is used in two main indication groups: (1) benign vocal fold pathologies (phonomicrosurgery); (2) malignant laryngeal tumours (early stage).

Benign vocal fold pathologies: polyp (typically unilateral, vocal misuse — shouting, smoking), nodule (typically bilateral, vocal overuse — teacher, singer; conservative first — voice rest + therapy), cyst (intracordal — deep lamina propria; epidermoid — superficial), Reinke's oedema (gelatinous swelling in Reinke's space — smoking + misuse), papilloma (HPV-related — recurrent, multifocal).

Early laryngeal cancer indications (AJCC 8th): Tis (carcinoma in situ), T1a (mid third of vocal fold, mobile, normal cord), T1b (anterior commissure involvement), T2 (supraglottic or subglottic extension without vocal fold immobility), selected T3 (limited to parahaemorrhagic). T4 and large transglottic — open partial/total laryngectomy preferred.

Oncological advantage: post-TLM 5-year cancer-specific survival 85-95% (Tis-T1), 75-90% (T2). Comparable to radiotherapy; surgery faster (1-day stay vs 6-7 weeks radiation), fewer long-term side effects (radiation fibrosis, xerostomia, second malignancy).

Functional advantage: voice quality restored in 2-4 months postop (mucosal wave recovery); most patients regain normal speech; professional voice (teaching) acceptable (similar voice quality to post-radiotherapy). Swallowing usually fully preserved. Breathing preserved (unless extensive resection).

Preoperative workup: (1) flexible laryngoscopy + stroboscopy (vocal fold mucosal wave + lesion motility); (2) anatomic accessibility — mouth opening (Mallampati, trismus), tongue size, dental status, neck mobility (extension); (3) imaging — contrast CT (neck and chest — tumour size + nodes + distant metastasis), MRI (soft tissue, cartilage invasion); (4) biopsy — direct or endoscopic (premalignant/malignant diagnosis); (5) voice analysis — preoperative voice recording (postop comparison), GRBAS score.

Patient selection — TLM appropriate? Adequate pulmonary function (tolerates general anaesthesia + jet ventilation), cardiac assessment, acceptable anatomic accessibility, motivation and adherence.

Counselling: if TLM not feasible, open partial laryngectomy or radiotherapy alternatives offered — decision based on patient preference + surgeon experience + tumour features.

Operative day: supine, shoulder roll (neck extension), general anaesthesia (TIVA — total IV anaesthesia useful; inhaled with laser-safe set-up also possible).

Ventilation: jet ventilation (Sanders or Hunsacker — small catheter + high frequency, open airway) or small laser-safe endotracheal tube (Mallinckrodt LaserTubus — dual cuff, aluminium-coated, saline-filled cuff). Jet pros: no tube in field, better view; cons: barotrauma risk, harder CO2 monitoring.

Laser safety: all staff laser-safety glasses + mask, patient eyes covered + wet gauze, skin shielded by wet gauze (reflective burn prevention), oxygen concentration <30% (fire prevention). Team training mandatory.

Laryngoscope placement: supine, neck extension, Kleinsasser or Steiner laryngoscope advanced through oral cavity, suspension-fixed. The larynx is visualised at vocal fold level.

Microscope + micromanipulator: operating microscope mounted, CO2 laser micromanipulator attached. Surgeon views through microscope + joystick directs laser spot. Vocal fold tissue visualised in high resolution.

Laser parameters: benign lesion (polyp, nodule) — low power (2-5 W), defocused, short pulses — vaporisation + minimal lamina propria damage; cancer resection — medium-high power (5-15 W), focused — cutting + margin assessment (intra-operative frozen).

Resection types (European Laryngological Society classification): Type I — subepithelial cordectomy (lamina propria surface); Type II — subligamentous; Type III — transmuscular; Type IV — total cordectomy; Type V — extended; Type VI — including anterior commissure.

Intra-operative frozen: in cancer surgery margins, when needed — to ensure clean margin. Positive margin extended.

Postoperative (24-48 h): voice rest (absolute — 24-48 h, even 7-10 days for benign), humidified oxygen, soft diet (cold first 24 h), antibiotic prophylaxis (especially for large resection), PPI (acid reflux prevention — wound healing), antiemetic (vomiting risks wound dehiscence).

Early complications: oedema (24-48 h, airway narrowing risk — particularly in bilateral cord surgery), bleeding (24-72 h — small vessels coagulated but larger vessels may be missed), anterior commissure web (Tis-T1b cases, prophylaxis: cautious bilateral resection + postop endoscopic check), tracheostomy need (rare — oedema or bleeding emergency).

Late: voice quality change (normalises 2-4 months — patience needed), granuloma formation (at resection site — often GERD-driven, may regress with PPI), web/synechia (anterior commissure adhesion — may need correction), recurrence (in benign: lifestyle + voice pattern; in cancer: 6-monthly endoscopic follow-up).

Postop voice therapy: early rehab improves voice outcome. SLP-led 2-4 weeks after surgery (post-healing); voice exercises, mucosal wave development, vocal hygiene education. For the related clinical reference, see vocal cord lesion page.

CO2 laser remains the cornerstone of laryngeal surgery, but newer lasers add capabilities.

KTP (potassium-titanyl-phosphate) 532 nm green — high haemoglobin absorption → effective in vascular lesions (angioma, telangiectasia, vascular polyps). Fibre delivery allows flexible endoscopic use → office laser under local anaesthesia (no hospitalisation). Increasingly used for early laryngeal dysplasia or small polyps.

Diode laser 980-1064 nm — deep penetration, haemostasis + vaporisation. Fibre-delivered → flexible application. For vascular lesions, polyps, papillomas.

Thulium laser 2000 nm — water absorption similar to CO2 but fibre-delivered. Both cutting and coagulation — usable in smaller working spaces (CO2 needs micromanipulator + suspension; thulium more flexible). Increasingly popular in laryngeal and pharyngeal surgery.

Robotic surgery (TORS — Transoral Robotic Surgery): daVinci system for laryngeal and pharyngeal surgery. Pros: 3D HD vision, ergonomic instrument motion, access to difficult anatomic regions (base of tongue, supraglottis). Cons: high cost, longer set-up, anatomic limits persist.

TORS + laser combination: robotic instrument + monopolar cautery or laser fibre — for supraglottic tumours, base-of-tongue cancer, hypopharyngeal lesions. CO2 laser micromanipulator can be mounted on robotic arm — modern hybrid.

Office laser procedures: fibre lasers (KTP, diode, thulium) for vocal fold surgery under local anaesthesia. Indications: small benign lesion (polyp, granuloma), recurrent papilloma, early dysplasia treatment. Pros: no hospitalisation, no GA, lower cost. Cons: more expensive equipment, limited indications, surgeon experience needed.

Future perspectives: AI-assisted laser control (automatic tissue-specific parameters), 3D image reconstruction (preoperative tumour mapping), photodynamic therapy (PDT — photosensitiser + laser; researched for early dysplasia), nanoparticle + laser hybrid systems (research).

Multidisciplinary approach: ENT/head & neck surgery + SLP + radiation oncology (in cancer for alternative or adjuvant assessment) + medical oncology (advanced cases) + dietitian + psychologist. For professional voice users (teachers, singers), joint follow-up by voice therapist + ENT. Related reading: our second opinion service.