Consideration of the complex relationship between sites of airway obstruction is paramount to choosing the correct surgical approach to treatment. Selecting patients who are likely to respond to surgery necessitates preoperative evaluation of individual patient anatomy. Lingual tonsil hypertrophy (LTH) is a common cause of hypopharyngeal obstruction. The degree of hypertrophy should be assessed, as it reflects the degree of morbidity. Therefore a universal language is necessary to compare the efficacy of removing different grades of lingual tonsils. A grading system for LTH is presented here and may be useful in selecting patients requiring specific lingual tonsil surgery versus tongue base surgery.
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Introduction
Surgical treatment of obstructive sleep apnea/hypopnea syndrome (OSAHS) has continued to evolve, with new techniques and modifications showing improvements in success. A simple preoperative patient selection method by which to determine the site of obstruction is both a necessity and priority in choosing patients who are likely to respond to surgical treatment. Therefore it is important to have a strategy to evaluate a patient’s airway that is both efficient and noninvasive. Implementation of these strategies in the selection process not only results in better outcomes, but also clarifies understanding of the need for surgery in specific populations of sleep apnea patients.
With the availability of transoral robotic surgery (TORS), lingual tonsillectomy has become an important adjunctive procedure in the treatment of OSAHS. It is commonly combined with TORS glossectomy, but often performed as a standalone procedure. Nevertheless, indications and efficacy of TORS lingual tonsillectomy have not been studied in detail. Because consideration of the size of faucial tonsils or adenoids is a widely accepted indicator for removal of lymphoid tissue, indications and efficacy of lingual tonsillectomy must also be based on lingual tonsil size.
Although any staging system represents only an approximation, it is important that we have a common language in describing lingual tonsil size. This type of outpatient screening is critical to perform before consenting a patient for an invasive airway procedure. As such, when evaluating obstruction at the tongue base, a universal scale to grade LTH may be beneficial for surgical treatment and protocol.
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Lingual Tonsil Hypertrophy Grading System
The lingual tonsils are often best visualized with the tongue protruded, but this is not true in all patients. Therefore lingual tonsils should be examined while the patient is awake with the tongue in multiple positions. Because multiple views of the tongue base allow for the best understanding of the lingual tonsils, awake endoscopy is an important complement to drug-induced sleep endoscopy for LTH grading.
The grading system consists of a 0 to 4 scale. Grade 0, which is extremely rare, denotes a complete absence of lymphoid tissue ( Fig. 18.1A ). Grade 1 has lymphoid tissue scattered over the tongue base ( Fig. 18.1B ). Grade 2 has lymphoid tissue covering the entirety of the tongue base with limited vertical thickness ( Fig. 18.1C ). Grade 3 consists of significantly raised lymphoid tissue covering the entirety of the tongue base, approximately 5 to 10 mm in thickness ( Fig. 18.1D ), and grade 4 represents lymphoid tissue 1 cm or more in thickness, rising above the tip of the epiglottis ( Fig. 18.1E ; Table 18.1). The vertical depth of the tonsils is a clinical approximate that should be judged by the otolaryngologist, with grade 3 being the first stage in which the tonsils have significant vertical height.
