Cordectomy
Transoral laser microsurgery (TLS) is a technique used for glottic carcinoma and is centered on the notions of “en bloc” resection (one piece of tissue) with microscopic evaluation for very small margins, allowing for oncologic success with maximum preservation of native tissue to optimize voicing and swallowing function.
The concept of compartmental surgery cannot always be applied in TLS, with “en bloc” resection, due to fact that the volume of the specimen does not always allow its adequate mobilization into the laryngoscope, precluding good visualization of the surgical margins, which are of paramount importance in this type of surgery. To overcome this problem, Steiner introduced the concept of transtumoral resection with a “piecemeal” technique. This allows for management of bulky lesions, offering three-dimensional evaluation of the extension and margins of the tumor, which would otherwise be impossible to evaluate since the specimen occupies the entire field of the laryngoscope. Margins need to be precisely assessed in close collaboration with the pathologist, using ink to designate the edge of the specimen.
If final histopathologic examination reveals tumor at the deep margins of resection, reresection is strongly recommended. In case of uncertain or positive superficial margins, a close endoscopic follow-up program should be performed. If negative margins cannot be obtained, the patient should undergo radiotherapy or open neck procedures.
Indications/Contraindications
Patients with early-intermediate glottic carcinomas (Tis-T1-T2 and selected T3) with good laryngeal exposure. Several parameters should be taken into account when evaluating adequate laryngeal exposure: body habitus, cervical rigidity, short neck, micrognathia and macroglossia, dental abnormalities (long teeth, prostheses, and malocclusion), previous radiotherapic or surgical treatments of the neck and spine that reduced cervical extension, opening of the mouth, and laryngeal suspension.
Oncologic contraindications are the involvement of the posterior paraglottic space with fixation of the cricoarytenoid joint, involvement of the posterior commissure, and infiltration of cartilaginous laryngeal framework. Tumor reaching the anterior commissure with extension above and below the glottic plane (transcommissural tumor) represents a relative contraindication, and each patient should be accurately evaluated and selected.
In the Clinical Setting
Key Points
CO2 Laser-Assisted Surgery
One of the most striking advances in treatment of selected glottic cancer is the possibility to perform transoral CO2 laser-assisted modulated cordectomies. In fact, this type of laser is the ideal device for transoral laser surgery (TLS) due to its physical properties as it transfers laser energy into heat energy, producing a photothermolytic reaction.
The CO2 laser can also be coupled with a new generation micromanipulator that focuses the laser beam in a spot size smaller than 300 microns, thus increasing the power density and minimizing power output. The power density is the amount of energy that is incident upon a specific unit of tissue area; it is expressed as watts/cm2 and is inversely proportional to the square of the laser beam radius. The energy fluence, expressed in Joules/cm2, represents the product of power density and time of exposure. A CO2 laser operates in continuous or pulsed modes. In a continuous mode, a steady flow of photons is emitted with little fluctuation in intensity, providing constant delivery of energy. Pulsed mode use an intermittent power source, providing sudden peaks of energy.
A pulsed CO2 laser coupled with a new generation micromanipulator, with limited time exposure of the tissue (< 100 millisecond), has the advantage of achieving a more precise cutting effect, with less heat scattering and thermal damage.
Cordectomies
To standardize a common terminology the European Laryngological Society published a consensus paper on a classification system that includes 6 types of endoscopic cordectomies: extension of the cordectomy and indications are detailed in Table 6.1 .
Custom-tailored laryngeal surgery through modulated cordectomies is based on the “excisional biopsy” concept, first introduced by Blakeslee (1984) as “en bloc” removal of the entire lesion, with a rim of surrounding healthy tissue. In this way, precise histopathologic diagnosis of the entire specimen and definitive therapeutic excision of the neoplasm are obtained in a single-stage procedure as far as clear surgical margins have been ensured. The same goal can be also achieved by the “piecemeal” approach, first introduced by Steiner for the management of bulky lesions, which will be explained later in the text.
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