Учебники / Operative Techniques in Laryngology Rosen 2008

78

Perioperative Care for Phonomicrosurgery

11.4Considerations for the Day of Phonomicrosurgery

Psychological reassurance of the patient on the day of surgery is extremely important. This involves seeing the patient outside the operating room before surgery, discussing any last-minute questions, and reviewing the surgical plans as well as the postoperative voice rest and recovery issues. Intravenous steroids should be used (10–20 mg Decadron) prior to the induction of general anesthesia for phonomicrosurgery. There is no indication for antibiotics or prolonged steroid use with most phonomicrosurgery cases.

11.5Postoperative Voice Rest

After phonomicrosurgery, a period of total voice rest is indicated in most situations. The duration of this voice rest is controversial and should be based on the nature of the pathol- 11 ogy treated during surgery, compliance of the patient, and the degree of dissection performed at the time of the surgical procedure. It should be emphasized to the patient and family members that total voice rest involves no sound production

whatsoever. Total voice rest includes no:

■Speaking

■Singing

■Whispering

■Humming

■Clicking

■Throat clearing

Alternative methods of communication should have been reviewed preoperatively and should be reviewed immediately postoperatively. They include the following:

■E-mail

■Pen-and-paper notes

■A wipe-off board

■Bell

■Whistle

■Text messaging

Silent cough is a helpful way to deal with the mucous sensation that sometimes occurs after phonomicrosurgery, minimizing trauma to the recently operated vocal folds. Silent cough involves the patient taking a large inhalation and performing a rapid, forced exhalation, without any sound production during the exhalation. Immediately after the exhalation, the patient should tuck his/her chin and perform a hard swallow. This in combination with frequent sips of water should address any issues patients have associated with mucous sensation and mucous build up in the throat while avoiding the use of phonotraumatic throat clearing activity. The typical duration for voice rest after phonomicrosurgery procedures ranges from 2 to 10 days. After the period of complete voice rest, light voice is

usually used for approximately 7–10 days. Light voice use often allows the patient to use a soft, conversational, breathy voice (this is not whispering) for approximately 5–10 min per hour. Patients should be reminded that this voice use limitation is not cumulative and should not be violated for any reason.

11.6Postoperative Voice Care

At the completion of strict voice rest, it is optimal for the patient to work with a speech–language pathologist for a short period as they reinitiate voice production. During this session, the speech–language pathologist emphasizes proper breath support, airflow, resonant voice production, and minimizes the risk of whispering or falsetto voice use. Often, there are also psychological aspects associated with the patient transitioning from total voice rest to voice use and thus, the speech– language pathologist can be helpful working with the patient on these issues.

Stroboscopy is an important monitoring tool after phonomicrosurgery and should be used to guide and assist in the graduation of the patient from total voice rest to light voice use to full voice use. Voice therapy after phonomicrosurgery is extremely important aspect of vocal recovery for almost all patients undergoing phonomicrosurgery. The optimal time for initiation of voice therapy after phonomicrosurgery is approximately 7–14 days after surgery. Singing voice therapy is also an important adjunctive treatment to the vocal rehabilitation of singers and nonsingers alike. Appropriate timing for initiation of singing voice therapy after phonomicrosurgery is highly variable, but typically, can be initiated approximately 3–4 weeks after surgery.

11.7Intralaryngeal Steroid Injection to Soften Postoperative

Scar in the Vocal Fold

A variety of factors known and unknown can contribute to significant postoperative stiffness and scarring of the vocal fold after phonomicrosurgery. When significant vocal fold stiffness after phonomicrosurgery is identified, often superficial steroid injections to the vocal folds are helpful to reduce permanent scar tissue formation and enhance wound healing of the vocal folds, resulting in better pliability, vocal fold closure and voice quality. Most frequently, this treatment is done on a monthly basis for 3 months, starting approximately 2–4 weeks after phonomicrosurgery. The steroid injection can often be done in the office under local anesthesia (see Chap. 33, “Peroral Vocal Fold Augmentation in the Clinic Setting”), using Decadron 10 mg/ml. Kenalog should be avoided due to the risk of particle deposits within the vocal fold.

 

Key Points

■The importance of involving the patient in the decision making for phonomicrosurgery cannot be overemphasized.

■It is important that the patient understand the importance of clearing their future voice demands for the 2–3 months after phonomicrosurgery to maximize the chances of successful recovery after surgery.

■A short period of strict postoperative voice rest is typically indicated and helpful, and then graduated voice use can be implemented under the care of the speech–language pathologist to maximize vocal recovery.

■Use of the speech–language pathologist for the preoperative and postoperative care of patients undergoing phonomicrosurgery is an important aspect of successful phonomicrosurgery and the patient’s optimal vocal recovery.

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79

Selected Bibliography

1Behrman A, Sulica L (2003) Voice rest after microlaryngoscopy: current opinion and practice. Laryngoscope 113:2182–2186

2Cho SH, Kim HT, Lee IJ, Kim MS, Park HJ (2000) Influence of phonation on basement membrane zone recovery after phonomicrosurgery: a canine model. Ann Otol Rhinol Laryngol 109:658–666

3Tateya I, Omori K, Hirano S, Kaneko K, Ito J (2004) Steroid injection to vocal nodules using fiberoptic laryngeal surgery under topical anesthesia. Euro Arch Otorhinolaryngol 261:489–4923

4Mortensen M, Woo P (2006) Office steroid injections of the larynx. Laryngoscope 116:1735–1739

Chapter 12
Management and Prevention	12
of Complications Related

to Phonomicrosurgery

12.1Fundamental and Related Chapters

Please see Chaps. 8, 10, and 11 for further information.

12.2Overview of Management

and Prevention of Complications Related to Phonomicrosurgery

There are a host of complications related to phonomicrosurgery that range from mild to serious and involve multiple factors, some of which are known (i. e., poor postoperative compliance with voice rest) and others unknown (i. e., unknown wound-healing phenotype).

The sections below discuss the nature of the complications, remedies for the complications, the natural clinical course, and prevention of these complications. Several overriding principles associated with the management and care of patients experiencing complications should be kept in mind as individual complications are discussed. Most importantly, the lines of communication between the patient and the voice care team are extremely important. Multiple studies have shown that patient satisfaction after medical care is related in large part to the patient’s perception of the health care provider’s interest in their care, which in turn is directly related to the provider’s ability to communicate with the patient. Thus, the most essential aspect of managing complications associated with phonomicrosurgery is to establish and maintain excellent lines of communication between the patient and the voice care team members.

12.3Surgical Indications and Contraindications

A variety of minor to major complications associated with phonomicrosurgery can occur in the oropharyngeal region. These include:

■Dental injuries

■Temporomandibular joint disorder aggravation

■Lingual anesthesia

■Dysgeusia

■Throat pain

All of these complications are associated with the positioning and placement of the laryngoscope. Most likely, these complications are related to the size of the laryngoscope and the duration of suspension of the laryngoscope. People have hypothesized that intermittently taking the laryngoscope off suspension to allow blood flow to the lingual area and remove pressure off the adjacent nerves may prevent or minimize these types of complications. However, this has not been proven scientifically. Given that much of the success of phonomicrosurgery is based on precision of surgery—which is directly related to the adequacy of the exposure of the vocal folds with a large bore laryngoscope—many of these complications are difficult to avoid completely. In fact, some laryngologists believe that these are not complications, but expected aspects of phonomicrosurgery, comparable to abdominal pain after an appendectomy.

Optimal management strategy for these complications includes preand perioperative communication with the patient regarding the possibility of these problems occurring and their subsequent management. A great majority of the time, lingual anesthesia, dysgeusia, and throat pain will be temporary in nature. Thus, the patient needs to be reassured that the symptoms that he/she experiences after phonomicrosurgery resolve with time. Dental injuries should be cared for by a dentist in a prompt fashion to shorten and minimize the patient’s aggravation and frustration. Dental injuries can also be minimized by taking great care of the dentition during placement of the laryngoscope and use of tooth guards over the mandibular and maxillary teeth. It is extremely rare for suspension microlaryngoscopy to induce temporomandibular joint disease; however, it is common that suspension microlaryngoscopy will aggravate preexisting temporomandibular joint pathology. For this reason, if the patient has temporomandibular joint disease, prior to phonomicrosurgery, it is wise to advise that most likely, the phonomicrosurgery procedure will exacerbate his/ her disorder, and that they may require medical or oromaxillofacial intervention postoperative to assist their recovery from this condition.

12.4Postoperative Dysphonia

There are varieties of aspects related to postoperative healing that can result in postoperative dysphonia after phonomicrosurgery. These include vocal fold scar, dependent edema of the vocal fold, granulation tissue at the operative site, failure of the

82 Prevention of Phonomicrosurgery Complications

microflap to adhere, and recurrence of the vocal fold pathology. Another related complication contributing to postoperative dysphonia is a patient with unreasonable expectations of voice quality and function after phonomicrosurgery. When this occurs, patients complain of a persistent postoperative dysphonia or even an exacerbation of their dysphonia after phonomicrosurgery, even though this may not in fact be the case. Unreasonable expectations after phonomicrosurgery stem from poor communication between the voice care team and the patient, especially regarding the typical postoperative clinical course in rehabilitation, plan, and the ultimate outcome of their phonomicrosurgical procedure, especially accounting for unsuspected vocal fold pathology found during phonomicrosurgery. The most important prevention method for minimizing the risk of patients developing unreasonable expectations associated with phonomicrosurgery is to establish an excellent line of communication between the patient and the voice care team members. This can be enhanced by using a special consent form for phonomicrosurgery, which details in plain language the risk of exacerbating their dysphonia or failure to improve their dysphonia due to a variety of factors. It is also important to maximize the lines of communication between the patient and the voice care team members by including family members,

12 singing teachers and speech–language pathologists involved in the decision making process to proceed with phonomicrosurgery and to avoid pressuring the patient into consenting to phonomicrosurgery (see Chap. 10, “Principles of Phonomicrosurgery”).

Prevention of vocal fold scar formation after phonomicrosurgery can be optimized by adhering to conservative tissue handling techniques during phonomicrosurgery, ensuring that the patient is compliant with regard to voice rest and light voice use after surgery, and finally, considering the use of postoperative, intra-vocal fold steroid injections to minimize permanent vocal fold scar after phonomicrosurgery (see Chap. 11, “Perioperative Care for Phonomicrosurgery”).

Physical complications after phonomicrosurgery of dependent edema of the vocal fold, granulation tissue at the operative site, and failure of the microflap to adhere are typically related to uncontrolled LPR, poor compliance with postoperative voice rest, and a foreign-body implantation associated with the surgical procedure. Difficulties with dependent edema of microflap can be solved with time, minimizing vocal abuse and treating concurrent LPR. Reducing the risk of granulation tissue at the operative site can be accomplished by reducing postoperative vocal abuse, treating LPR perioperatively and ensuring that there is no char from the laser or extraneous foreign bodies (e. g., metal flakes from instrumentation) implanted at the operative site during phonomicrosurgery. Difficulties with the microflap adhering are rare, but when they occur, it is most likely from varieties of issues. These include poor compliance with voice rest, overly traumatic handling of the microflap, and fenestration of the microflap inferiorly, which results in nonadherent epithelial coverage at the operative site, leaving the microflap nonadherent to the underlying vocal fold. Great care of the soft tissues of the microflap is essential for preventing these complications.

The last aspect of poor voice results associated with phonomicrosurgery involves the formation of recurrent vocal fold

 

pathology after phonomicrosurgery. This can be associated with uncontrolled LPR, voice abuse, and/or incomplete excision of the vocal fold pathology. Prevention of the latter can be done by carefully examining the vocal fold at the time of microflap excision to ensure that all aspects of the vocal fold pathology have been completely removed. This can also be achieved by a performing careful vocal fold palpation with the back of a curved instrument, and feeling for persistent vocal fold pathology within the microflap or deep to the microflap. In addition, it is important for the surgeon to perform careful visual inspection of the operative site for persistent pathology.

12.5Medical Complications Associated with Phonomicrosurgery

Fortunately, significant medical complications after phonomicrosurgery are extremely rare. They include airway compromise, bleeding from the operative site, and infection. Overly aggressive vocal fold injection, especially in the case of poor vocal fold abduction (unilateral with a contralateral vocal fold paralysis or bilateral) can result in airway compromise. This is most commonly treated with systemic steroids and careful observation. Bleeding from the vocal folds after phonomicrosurgery is extremely rare and most notably occurs after removal of recurrent respiratory papillomatosis. In fact, when there is significant bleeding after phonomicrosurgery for recurrent respiratory papillomatosis, it usually indicates incomplete removal of the recurrent respiratory papillomatosis disease. Infection rarely occurs after phonomicrosurgery, and in fact, for this reason antibiotics are rarely indicated for this surgery.

Key Points

■The lines of communication and relationship between the surgeon and the patient are absolutely essential for the management and prevention of complications related to phonomicrosurgery. The surgeon should be completely forthright and honest when discussing with the patient potential and real complications of phonomicrosurgery and their subsequent management.

■It is imperative for the surgeon to establish reasonable expectations regarding voice quality and timeline of recovery with the patient to optimize vocal recovery and achieve patient satisfaction from a voice quality perspective.

■Many significant complications associated with phonomicrosurgery can be prevented by strictly adhering to principles of conservative tissue handling and excision.

Chapter 12

83

Selected Bibliography

1	Anderson TD, Sataloff RT (2004) Complications of collagen in-	3
	jection of the vocal fold: report of several unusual cases and re-	4
	view of the literature. J Voice 18:392–397

2Rosen CA, Andrade Filho PA, Scheffel L, Buckmire RA (2005) Oropharyngeal complications of suspension laryngoscopy: a prospective study. Laryngoscope 115:1681–1684

Rosen CA, Villagomez VJ (2001) A unique complication of microflap surgery of the vocal fold. Ear Nose Throat J 80:623–624 Woo P, Casper J, Colton R, Brewer D. Diagnosis and treatment of persistent dysphonia after laryngeal surgery: a retrospective analysis of 62 patients. Laryngoscope 104:1084–1091

Chapter 13
Principles	13
of Laser Microlaryngoscopy

13.1 Fundamental and Related Chapters

13.2.2 Tissue Interaction

Please see Chaps. 6, 10, 21, 22, 24–30 for further information.

13.2Laser Physics

The modern challenge of using medical lasers is the surgeon’s ability to deliver the right amount of energy at the right wavelength to the right tissue while minimizing damage to collateral tissue. This process by which laser energy is restricted to a particular site is a result of the selective absorption of the chromophores at that site and was first described by Anderson et al. as “selective photothermolysis.” The following section will consider the major concerns confronting surgeons when using lasers in a clinical setting.

13.2.1 Wavelength

Unlike the energy emitted from ambient light sources, laser light is monochromatic and usually of a single wavelength, with all photons collimating into a single, thin beam of homogeneous energy. The challenge of laser surgery is finding a wavelength in which energy is absorbed by target tissue and scattered or transmitted by surrounding structures. When laser light is delivered to the chromophores within the target, energy is absorbed within that tissue. Some common chromophores targeted by surgical lasers are hemoglobin, melanin, water-containing soft tissue, and covalent bonds found in major structural proteins. Depending on the chosen wavelength, either coagulation, vaporization, or a combination both will take place. Tissues heated to 80–100°C will suffer plasma denaturation, resulting in vessel closure and hemostasis. Temperatures above 100°C will cause vaporization through rapid volumetric expansion of intracellular water stores, a technique that is useful for separating or ablating tissues. A laser’s wavelength also correlates with the depth at which the energy is delivered. Therefore, greater depths of tissue disruption are achieved at longer wavelengths until reaching the wavelength specific for the absorption of water, near 2,000 nm.

While appropriate wavelength determination is critical for specific tissue targeting, the time in which the energy is delivered is also of consequence. Under prolonged exposure times, photothermal effects cause collateral coagulation necrosis, as heat transfers uniformly to surrounding tissues. However, if the pulse width is too short, the absorbing tissue may heat rapidly. Extreme temperature differences between target tissue and collateral structures have been shown to cause vaporization and shock wave damage, commonly referred to as a photomechanical effect. Consequently, nonspecific thermal damage occurs when the pulse width exceeds the thermal relaxation time for the tissue. Thus, the larger the specific target, the larger the thermal relaxation coefficient. Generally, subcellular organelles achieve photolysis within a nanosecond domain, cellular disruption occurs on a microsecond scale, and hemostasis is achieved within millisecond exposure times. In actual practice, all of these interactions occur concomitantly, but by selecting the proper wavelength, intensity, and pulse duration, the surgeon can maximize the desired effects.

13.2.3 Delivery Systems

While recent advancements in the field have provided more options for delivery systems, laser type is still the major determinant. Traditionally, the CO2 laser has been of the most use for laryngologists. Traditionally, an articulating arm is required for the delivery of CO2 laser energy to the treatment site. This delivery system requires a hollow tube with several joints or articulations that allow some maneuverability. At each articulation, a set of mirrors are positioned to reflect the beam around the corner. Great care must be taken when using such a system, as jarring or vibrations may cause misalignment within the internal mirror system. Laryngologists have also benefited from the addition of several attachments used at the end of articulating arms. Micromanipulators are used to couple laser operation and microscopy. A greater amount of precision and beam control can be managed by hand-manipulated devices.

The micromanipulators can control laser spot size. This is an essential variable from an ultimate tissue interaction perspective. Spot size, power, energy setting, and duration have a major role in the effect of the laser on the tissue. The smaller the spot size, the greater the energy delivered per unit area. Thus, when working with the typical very small spot sizes found with the CO2 laser micromanipulators, the power settings should be kept quite low.

86	Principles of Laser Microlaryngoscopy

Many of the other lasers used in the field are delivered via fiberoptic cables. With the advent of this technology, laryngologists are able to use endoscopes, such as the flexible laryngoscope with a working channel to gain access. As with the articulating arm, fiberoptics is used in a noncontact manner. Normally a 1- to 2-mm distance from target tissue is optimal, as spot size rapidly increases with distance from tissue, causing a great reduction in laser energy delivered and lack of precision.

13.2.4 Types of Laser

Although a myriad of lasers are employed in the treatment of head and neck pathology, there are only a few types in the field of laryngology.

Traditionally the CO2 laser is the workhorse of laryngologic lasers. Its specific wavelength of 10,600 nm is absorbed by water found in soft tissues and is independent of tissue color. CO2 lasers emit continuous or pulsed waves, which can be focused into a thin beam and used to cut like a scalpel or defocused to vaporize, ablate, or shave tissue. The CO2 laser’s ability to deliver energy endoscopically, utilize no-touch technology, and provide a marked reduction in postoperative swelling, contributing to its widely accepted clinical use.

13 Pulse dye lasers (PDL) emit radiation at a 585-nm wavelength, which corresponds with the oxyhemoglobin absorption band. This wavelength penetrates the mucosa well, minimizes absorption by melanin in the overlying mucosa, and offers excellent selective absorption by microvasculature. A lasing medium of rhodamine dye is excited by flash lamps and is delivered with a pulse width just under the thermal relaxation time of small vessels. While pulse dye lasers have been employed in many areas of laryngology, relative small pulse width and the cost of replacement dye medium have detracted from the benefits of such technology.

YAG lasers use a yttrium–aluminum–garnet crystal rod that is manufactured with specific rare earth elements dispersed within the crystal rod. The difference in the chemical properties of each element gives the laser a specific wavelength and thus a different surgical application. All YAG lasers may be continuous, pulsed, or Q-switched. Q switching, much like a capacitor in a circuit, is the ability to pulse the laser, while at the same time increasing peak energy power, shortening pulse width, and improving the consistency of the lasers output throughout the pulse. Normally, continuous and pulsed modes are delivered via fiber optic cables, while articulating arms use Q switching.

The holmium:YAG (Ho:YAG) laser uses an active medium of YAG crystal with holmium dispersion. Its beam falls near the infrared region of the electromagnetic spectrum at 2,100 nm. Its principle use is to ablate bone and cartilage, and has found specific laryngologic application in laser incisions and dilation for the treatment of subglottic stenosis.

The neodymium-coupled YAG (Nd:YAG) laser is one of the most clinically diverse lasers in current use. A near infrared light is emitted at 1,064 or 1,320 nm. Nd:YAG lasers may be delivered fiber optically to coagulate tissue or through sapphire probes, allowing for low-powered delivery with minimal ther-

 

mal diffusion. Sapphire probes create a cutting and vaporization effect similar to that of CO2 lasers.

The potassium–titanyl–phosphate (KTP) laser uses a 1,064nm YAG laser filtered through a KTP crystal that effectively halves its wavelength to 532 nm, producing a brilliant green light, well within the visible spectrum. The KTP laser is the newest addition to the laryngologist armament. Its 532-nm wavelength corresponds to a greater specific absorption for oxyhemoglobin. Recent studies have shown great promise in the surgical use of this solid-state laser, including shorter pulse width and less nonspecific tissue damage. The KTP laser also can deliver energy through a small diameter fiber optic, resulting in less mechanical damage to endoscopic channels.

It is important to recognize that a laser is nothing more than a tool in the surgeon’s armamentarium, much like forceps, microscissors, or bipolar cautery. It is a common misconception that microspot CO2 lasers allow increased precision over cold techniques. In fact, microlaryngeal cold instrumentation are superior to microspot laser technology in terms of precision, while avoiding collateral heat damage that can be associated with laser use.

13.3Surgical Indications and Contraindications

Ideal indications for CO2 laser are:

■Glottic/posterior glottic stenosis

■Subglottic/tracheal stenosis

■Bilateral vocal fold paralysis (arytenoidectomy, transverse cordotomy, …)

■Teflon granuloma of the larynx

■Squamous cell carcinoma of the glottis (T1–select T2)

Additional indications for CO2 laser include:

■Papillomatosis (especially with extensive disease)

■Vocal fold varix (select cases)

■Saccular cyst of the larynx

Relative contraindications for CO2 laser are:

■Most benign lesions of the vocal folds:

■Nodules

■Vascular lesions

■Cysts

■Polypoid corditis

Indications for Nd:YAG laser comprise:

■Large hemangioma of the larynx

■Glottic/subglottic stenosis (CO2 laser generally preferred)

Indications for pulse dye laser/pulsed-KTP laser are: ■ Papillomatosis

 

■Leukoplakia

■Granuloma

■Vascular lesions

■Polypoid corditis

13.4Equipment: Laser Microlaryngoscopy Setup

High-quality operating microscope with 400-mm lens

Large-bore laryngoscope (largest diameter possible if operating on vocal folds/supraglottis) (see Chap. 10, Table 10.1)

Suspension laryngoscope with suction channel and jet ventilation port if operating on subglottis/trachea

•Ossoff–Pilling effective for subglottis/upper trachea (proximal)

•Subglottiscope for upper/mid-trachea (distal)

Suspension system

•Gallows suspension

•Fulcrum suspension (e. g., Lewy apparatus and table-mounted Mayo)

Operating chair with arm supports

• Alternative: Mayo stand with pillow/foam

Instrumentation (available from Karl-Storz

(Culver City, CA), Medtronic ENT [Jacksonville, Fla.], Instrumentarium [Montreal, Quebec, Canada])

•Injection device for hydrodissection (Orotracheal injection device, Medtronic ENT)

•Small (0.5 × 2 cm) cotton pledgets

•1:10,000 epinephrine

•Velcro strap or cloth/silk tape

•Microcup forceps (see Chap. 10, Fig. 10.2)

•Micro-ovoid cup forceps (see Chap. 10, Fig. 10.3)

•Microscissors

–Curved, left and right

–Up angled

•Curved alligator forceps

•Straight alligator forceps

•Microlaryngeal suctions

•Triangular (Bouchayer) forceps

•Hopkins Telescopes

–Diameter 4–5mm, length 30cm or more

–0, 30, and 70°

CO2 laser

Micromanipulator with 250-μm spot size (coupling device between microscope and laser)

Jet Venturi needle or Hunsaker Mon-Jet tube

Chapter 13

87

Dilation equipment:

•Ventilating bronchoscopes: 5, 6, 7, and 8 French (if no trach present)

•Laryngeal rigid dilators: 20–50 French (if trach present)

•Pneumatic balloon dilator

Jet ventilation machine

Laser safety materials

•Moistened eye pads

•Moistened towels/surgical drapes

•Laser-safe endotracheal tube (if applicable)

•Eye protection for operating room personnel

13.5CO2 Laser Safety Guidelines

13.5.1 General Guidelines (Fig. 13.1)

In the vast majority of laryngeal laser surgery, relatively lowpower settings are employed to minimize collateral heat damage. For the purposes of this chapter, all laser settings described are used in the context of a micromanipulator with a 250-μm spot size. Laser settings are generally set below 10 W, using an intermittent or superpulse mode. Continuous firing mode is rarely employed and can sharply increase the chances of immediate (laser fire) or late complications (glottic web/stenosis), due to the substantial power delivery in this mode. Intermittent delivery or pulsed delivery (e. g., superpulse) allows some thermal relaxation time in between laser delivery, thus minimizing collateral heat damage.

Fig. 13.1  Intraoperative photograph illustrating the key laser safety concepts, including wrapping the patient’s head and upper body with moistened towels, the use of a laser-safe endotracheal tube, low-O2 settings, and eye protection for operating room personnel

88

Principles of Laser Microlaryngoscopy

13.5.2 CO2 Laser Settings

(For most applications in the larynx, the following range of laser settings can be employed):

■4–8 W, intermittent mode (0.1 s “on” and 0.5 s “off”)

■Best for precision work at the vocal fold level

■Least collateral damage

■4–8 W, superpulse mode

■Increased tissue ablation

■Use sparingly near vocal folds to minimize collateral damage

■4–6 W, continuous

■Maximum laser ablation: useful for cartilage ablation (arytenoidectomy)

		13.5.3 Safety Protocol
		The key to laser safety in the operating room (OR) is consistent
		and methodical adherence to an established protocol. A simple
		yet effective protocol is to fully address three areas of safety
		prior to proceeding (Fig. 13.1). The surgeon must answer affir-
		matively to the following questions before firing the laser:
13
		1. Is the patient’s body protected?
		a) Moistened eye pads
		b) Soaked surgical towels around the face and upper chest
		2. Is the endotracheal tube/airway protected?
		a) Laser-protected tube must be used
		b) Saline filled ETT balloon
		c) Moist Cottonoid covering/protecting the balloon
		d) O2 concentration of 30–35% or less
		If jet ventilation is used, then suspend ventilation during fir-
		ing of the laser.
		3. Are the OR personnel protected?
		a) Eyeglasses or plastic goggles with side protectors for all
		personnel
		b) Laser warning signs on all OR doors

13.6 Surgical Principles

13.6.1 Smoke Evacuation

Laser vaporization results in significant smoke accumulation at the operative site, and must be rapidly removed to maintain visualization. Suction tubing should be connected to a side channel of the laryngoscope to maintain continuous smoke evacuation. It should be noted, however, that supplemental smoke evacuation may be necessary. Platform suction (Fig. 13.2) is often employed, which provides not only smoke evacuations, but also protects the distal tissues from inadvertent laser damage.

13.6.2Protecting Surrounding Tissue from Laser Damage

Platform suction can be used, as indicated above, or a moistened Cottonoid can be placed over the area to be protected.

13.6.3 Maintenance of a Clean Surgical Field

The CO2 laser causes the accumulation of carbonaceous debris (Fig. 13.3), or char at the surgical site. This desiccated debris is resistant to laser penetration due to the low water content. Therefore, it must be removed periodically by wiping the tis-

Fig. 13.2  Platform suction device

Fig. 13.3  Carbonaceous debris from laser ablated tissue, right vocal fold. This must be removed for efficient treatment of tissue with the CO2 laser

 

sues with a saline-soaked Cottonoid, or suction removal. Also, active bleeding at the surgical site usually prevents laser vaporation. Hemostasis must be achieved before proceeding (by either defocusing the laser beam, or applying epinephrinesoaked Cottonoids for 1–3 min to the area of bleeding).

13.7Complications and Their Treatments

13.7.1 Laser Fire

A laser fire is the most feared complication in laryngology, although it is quite rare today. This is likely due to better education and awareness of laser safety issues, as well as improved laser-safe endotracheal tube design. In the unlikely event of a laser fire with an indwelling endotracheal tube, the following steps should be followed:

■Immediate removal of ETT

■Turn off anesthetic gas/oxygen delivery

■Mask patient with 100% O2

■Intubate with small 4.0–5.0 ETT

■Evaluate trachea with rigid bronchoscopy with carbon debris removal

■Flexible bronchoscopy to evaluate more distal tracheobronchial tree

■Manage airway after extent of injury is established (options to be considered):

■Extubate, observe in monitored setting

■Remain intubated, treat with corticosteroids/antibiotics

■Tracheostomy

13.7.2 Tracheal Perforation

This can lead to tracking of air into the neck and down into the mediastinum. Further dissection can lead to pneumothorax. Ei- therconditionshouldbeevaluatedwithachestx-rayandconsul- tation with cardiothoracic surgery/pulmonology specialists.

Key Points

■The key components that determine a laser’s interaction with tissue are wavelength, intensity, spotsize and pulse duration.

■The CO2 laser is the workhorse laser for laryngotracheal work, and the ideal indications include:

■Glottic/posterior glottic stenosis

■Subglottic/tracheal stenosis

■Bilateral vocal fold paralysis (arytenoidectomy, transverse cordotomy)

■Teflon granuloma of the larynx

■Squamous cell carcinoma of the glottis (T1–se- lect T2)

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89

■Papillomatosis (especially with extensive disease)

■Vocal fold varix (select cases)

■Saccular cyst of the larynx

■The CO2 laser is generally not a good choice for the removal of benign lesions of the vocal fold, such as polyps, or cysts, or nodules, due to decreased precision, and unintended collateral heat damage, which can result in scarring and dysphonia.

■CO2 laser settings generally employ low-wattage settings (4–8 W) in an intermittent or superpulse mode to minimize collateral damage to the tissues. The continuous-beam setting should be used sparingly, and is most appropriate for cartilage ablation.

■A laser safety protocol should be employed in all

cases where the CO2 laser is used. The key concepts are protection of the patient (moist towels), protection of the endotracheal tube (laser safe,

with O2 concentration of 35% or less), and protection of operating room personnel (safety glasses).

Selected Bibliography

1Anderson R, Parrish J (1983) Selective photothermolysis: precise microsurgery by selective absorption of pulsed radiation. Science 220:524–527

2Absten GT, Joffe SN (1985) Lasers in medicine. Chapman and Hall, London

3Buckmire R et al (2006) Lasers in laryngology. In: Merati AL, Bielamowicz SA (eds) Textbook of laryngology. Plural, San Diego, pp 190–199

4Ossoff RH (1989) Laser safety in otolaryngology—head and neck surgery: anesthetic and educational considerations for laryngeal surgery. Laryngoscope 99(Suppl.):1–26

5Schramm VL, Mattox ED, Stool SE (1981) Acute management of la- ser-ignited intratracheal explosion. Laryngoscope 91:1417–1426

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