Introduction
Transoral CO 2 laser microsurgery is a well-established treatment for cancer of the larynx, particularly for T 1 or T 2 glottic cancer. Alternative treatment options include radiation therapy or hemilaryngectomy for glottic cancer and supraglottic or supracricoid laryngectomy for supraglottic cancers. The advantages of using CO 2 laser with an operating microscope include microsurgical precision, excellent intraoperative detail, and a dry surgical field. Swallowing and speech outcomes exceed that of external surgical approaches and radiation therapy. Other advantages include patient convenience, savings both on direct and hidden patient costs, reserving radiation as potential therapy for recurrence or for second primaries, and that patients who recur are more likely to have larynx preservation.
Surgeons must familiarize themselves with the laser machine, its settings and delivery system, and its tissue effects before attempting to use it clinically and should hone their skills on animal tissue and then small tumors. They must also understand the safety aspects relating to CO 2 laser surgery.
Key Operative Learning Points
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Surgeons without prior experience using a laser should start with simpler cases (e.g., smaller cancers of the aryepiglottic fold, supraglottis, or medial wall of the piriform fossa).
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Spot size, focus, power, and mode (super pulse [SP]/pulsed/continuous) are important to achieve the desired effects and may be altered during an operation for different tissues or to achieve coagulation, cutting, or vaporization effects.
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Check the alignment of the aiming beam with the laser beam.
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Avoid past-pointing, as this may cause laser fires. Be aware of reflection of the laser beam off of instruments and scopes, and ensure that the backstop is correctly positioned to protect the endotracheal tube.
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Apply constant traction to tissues to define dissection planes and facilitate dissection.
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Maintain a relatively slow, smooth hand-speed.
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Use Ligaclips, not diathermy, for large vessels to avoid postoperative bleeding.
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Minimize tissue injury by employing super pulse (SP) as opposed to continuous mode.
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One may have to resect structures (e.g., suprahyoid epiglottis) to improve access.
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Debulking the cancer allows one to create space within which to move tissues around.
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Distinguish the cancer from normal tissue by transecting it and checking pliability (cancer tissue is rigid) and colors of tissues (cancer chars and is brown/black when transected) ( Fig. 11.1 ).
Fig. 11.1
Transected cancer of vocal cord; note clear demarcation between dark brown transected cancer and pale-colored normal tissue of paraglottic space.
With permission from Fagan JJ, Steiner W: Transoral CO 2 laser microsurgery for cancers and other pathology of the upper aerodigestive tract. Available at https://vula.uct.ac.za/access/content/group/ba5fb1bd-be95-48e5-81be-586fbaeba29d/CO2%20laser%20transoral%20microsurgery%20_TLM_.pdf
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Bread slice ( Fig. 11.2 ; see also Fig. 11.1 ) the cancer to determine its depth and to ensure an adequate deep resection margin.
Fig. 11.2
Bread slicing the cancer.
With permission from Fagan JJ, Steiner W: Transoral CO 2 laser microsurgery for cancers and other pathology of the upper aerodigestive tract. Available at https://vula.uct.ac.za/access/content/group/ba5fb1bd-be95-48e5-81be-586fbaeba29d/CO2%20laser%20transoral%20microsurgery%20_TLM_.pdf
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Do not lose orientation of specimens; pin specimens to cork that is placed in formaldehyde and make a detailed drawing for the pathologist and in the patient’s notes of the precise location of resected specimens.
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What constitutes an adequate resection margin is controversial and might determine whether to return a patient to the operating room for an additional resection, whether to advise close surveillance, or whether to recommend adjuvant radiation therapy. Factors include tumor site, size, function (voice and swallowing), patient fitness, extent of the initial resection (e.g., onto cartilage or carotid), not knowing precisely where the positive or close margin is located, and reliability of follow-up.
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Pathologists are reticent to do frozen sections on very small resections (e.g., T 1 glottic cancer).
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A surgeon’s impression of the adequacy of a resection as seen through the microscope is important; one may adopt a watchful waiting approach even when the cancer is reported to be “present at the margin” with the knowledge that cells are denatured and killed at the margin by the laser.
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Follow laser safety procedures ( Table 11.1 ).
TABLE 11.1
Laser Safety Precautions and Management of Laser Fires
Safety Precautions (Surgical)—Develop a Check LIST Which Includes
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Place laser warning signs outside the operating room.
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Cover windows and securely close doors while the laser is “on” or in “standby” mode.
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Personnel and patients must use eye protection specific for CO 2 laser; it should also be available at entrances to the room; standard prescription eyeglasses are sufficient for CO 2 laser; side-guards are recommended.
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Tape the patient’s eyes shut and cover them with moist pads.
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Do not use alcohol or flammable cleaning prep solutions in the operating room.
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Use flame retardant materials and drapes.
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Keep an open container filled with water or saline immediately available to douse a laser fire.
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Place moistened swabs/sponges adjacent to the path of the laser beam to protect surrounding tissues and structures.
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Minimize the possibility of a “blow-torch effect” by carefully protecting endotracheal tubes with wet cloth or neuro patties.
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The locking key to laser machine should be accessible only to persons trained in the use of laser; it should not be stored in or on the laser machine but kept in secure location; some lasers have electronic keypads.
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Keep the laser turned off or in “standby” mode unless in use.
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Instruments should have brushed, beaded, or sand-blasted surfaces to prevent reflection of the laser beam.
Safety Precautions (Anesthetic)
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“Nonflammable” endotracheal tubes may be used. (All tubes are flammable.)
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Fill the cuff of the endotracheal tube with saline colored with methylene blue.
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Maintain inspired oxygen (FiO 2 ) as low as clinically feasible (<30% FiO 2 ).
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Wait a few minutes for the oxygen concentration in the airways to drop before approving activation of the laser.
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Avoid nitrous oxide if possible.
Laser Airway Fire
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Turn off laser at emergency switch.
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Turn off all anesthetic gases.
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Remove swabs and flammable materials from the airway.
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Immediately remove the endotracheal tube.
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Pour saline into the airway.
With permission from Apfelbaum JL, Caplan RA, Barker SJ, et al: Practice advisory for the prevention and management of operating room fires: an updated report by the American Society of Anesthesiologists Task Force on Operating Room Fires. Anesthesiology 118(2):271-290, 2013.
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Preoperative Period
Preoperative assessment is directed at the patient’s general fitness for surgery, counseling about risk factors, the ability to cope with a degree of aspiration (supraglottic cancer resections), and to determine whether the cancer is amenable to endoscopic laser resection.
History
- 1.
History of present illness
- a.
Risk factors: Smoking
- b.
Pulmonary status: Aspiration, smoking
- c.
Pointers to synchronous primaries
- a.
- 2.
Past medical history
- a.
Previous squamous cell carcinomas
- b.
Previous radiation to head and neck
- a.
- 3.
Medical illness
- a.
Ability to deal with aspiration and dysphagia
- b.
Fitness for surgery
- a.
- 4.
Medications
- a.
Anticoagulants
- b.
Allergies to antibiotics
- a.
- 5.
Mental and social status
- a.
Ability to overcome challenges related to speech and swallowing
- b.
Ability to give informed consent
- c.
Employment and hobbies: May be affected by speech or swallowing impairment
- a.
Physical Examination
- 1.
Primary cancer
- a.
Extension to subglottis, pyriform fossa, pre-epiglottic space, base of tongue
- b.
Invasion of thyroid cartilage
- c.
Cervical metastases
- a.
- 2.
General health
- a.
Cardiovascular
- b.
Respiratory
- c.
Mental
- a.
Imaging
- 1.
Chest radiograph
- a.
Metastases
- b.
Pulmonary and cardiac status
- a.
- 2.
CT scan (selected cases only)
- a.
Thyroid cartilage invasion
- b.
Pre-epiglottic space invasion
- c.
Through cricothyroid membrane
- a.
- 3.
MRI (selected cases only)
- a.
Complements CT scan
- a.
Indications
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Biopsy and debulking of cancer causing airway obstruction
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Biopsy cancer located deep in ventricle or false vocal cord by cutting through false vocal cord
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Resect cancer of the larynx
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Treat sequelae of CO 2 laser or radiation (e.g., laryngeal stenosis, edema, glottic web).
Contraindications
- 1.
Patient factors
- a.
Medically unfit
- b.
Inability to give informed consent
- c.
Inability to overcome challenges relating to speech and swallowing
- a.
- 2.
Tumor factors
- a.
Unresectable (e.g., invading thyroid cartilage)
- b.
Distant metastases
- c.
Unacceptable morbidity
- a.
- 3.
Surgical factors
- a.
Inadequate expertise
- b.
Inadequate surgical access
- a.
Preoperative Preparation
- 1.
Evaluations by
- a.
Surgeon
- b.
Anesthesiology (if airway is compromised)
- c.
Speech and swallowing therapist
- a.
- 2.
Discontinue anticoagulation drugs (except for minor resections, e.g., T 1 glottic cancers).
Operative Period
Anesthesia
The surgeon and anesthesiologist must agree on how to maintain an airway for the specific patient. The principal challenges are to use an endotracheal tube that permits the surgeon to work in the confined space of the larynx and to eliminate the risk of laser fires.
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Airway options
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Endotracheal intubation (nasal or oral)
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Intermittent jet ventilation
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Intermittent extubation with lasering during apneic intervals
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Open airway
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Spontaneous breathing with anesthetic gases administered through the suction port of the laryngoscope
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Intravenous anesthesia
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Tracheostomy
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- •
Endotracheal tube: All tubes are flammable; therefore the problem is not the type of tube but perforating the tube when the O 2 concentration in the tube is too high. I use a regular plastic tube but protect it with a strip of wet cloth ( Fig. 11.3 ) or with neuro patties. The cuff is filled with saline to flood the airway if the cuff is punctured.
Fig. 11.3
Tube protected by strip of wet cloth.
With permission from Fagan JJ, Steiner W: Transoral CO 2 laser microsurgery for cancers and other pathology of the upper aerodigestive tract. Available at https://vula.uct.ac.za/access/content/group/ba5fb1bd-be95-48e5-81be-586fbaeba29d/CO2%20laser%20transoral%20microsurgery%20_TLM_.pdf
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Avoid nitrous oxide if possible.
- •
Maintain inspired oxygen FiO 2 less than 30%.
Positioning
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Position the anesthetic machine at the patient’s feet to create space at the patient’s head.
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Position the patient supine with neck extended.
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Insert a gum guard to protect the upper teeth.
Perioperative Antibiotic Prophylaxis
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No antibiotics are necessary.
Monitoring
- •
Implement routine anesthesia monitoring.
- •
Maintain FiO 2 at less than 30%.
Instruments and Equipment to Have Available ( Fig. 11.4 )
Adequate exposure of the cancer is critical; hence a variety of laryngoscopes and pharyngoscopes with integrated suction channels to remove smoke is essential. Instruments must have mat or black surfaces to prevent reflection of the laser. Two suction systems are required, one attached to the laryngoscope to extract smoke from the surgical field and the other attached to the handheld suction tube.
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Operating microscope with fitting for micromanipulator
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CO 2 laser machine with micromanipulator
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Rigid 0 degree endoscope to examine the subglottis if microscopic view is inadequate
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Safety glasses
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Distending laryngopharyngoscope to access the hypopharynx and supraglottic larynx
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Large laryngoscope to access endolaryngeal, upper tracheal, and hypopharyngeal lesions
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Small laryngoscope for difficult exposures such as anterior commissure, subglottis, and upper trachea
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Light carrier
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Laryngoscope holder
- •
Grasping forceps (different sizes)
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Microforceps (small vocal fold lesions)
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Coagulation forceps
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Suction tubes (insulated for diathermy)
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Diathermy cable
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Ligaclip applicators (left and right)
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Adjustable supporting plate for laryngoscope holder (not essential)
