TRANSORAL ROBOTIC SURGERY OF THE TONGUE BASE IN OBSTRUCTIVE SLEEP APNEA-HYPOPNEA SYNDROME: ANATOMIC CONSIDERATIONS AND CLINICAL EXPERIENCE

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1 ORIGINAL ARTICLE TRANSORAL ROBOTIC SURGERY OF THE TONGUE BASE IN OBSTRUCTIVE SLEEP APNEA-HYPOPNEA SYNDROME: ANATOMIC CONSIDERATIONS AND CLINICAL EXPERIENCE Claudio Vicini, MD, 1 Iacopo Dallan, MD, 2 Pietro Canzi, MD, 1 Sabrina Frassineti, MD, 1 Andrea Nacci, MD, 2 Veronica Seccia, MD, 2 Erica Panicucci, MD, 3 Maria Grazia La Pietra, PhD, 1 Filippo Montevecchi, MD, 1 Manfred Tschabitscher, MD 4 1 Department of Special Surgery, Ear, Nose, and Throat, and Oral Surgery Unit, Ospedale Morgagni Pierantoni, University of Pavia in Forlì, Italy 2 Ear, Nose, and Throat Unit, Azienda ospedaliero-universitaria Pisana, Pisa. iacopodallan@tiscali.it 3 Department of Experimental Pathology, University of Pisa, Pisa, Italy 4 Department of Systematic Anatomy, University of Wien, Wien, Austria Accepted 22 October 2010 Published online 11 March 2011 in Wiley Online Library (wileyonlinelibrary.com). DOI: /hed Abstract: Background. The purpose of our work was to describe, through cadaveric dissection, the anatomy of the tongue base with a robotic perspective and to demonstrate the feasibility of this approach in case of tongue base hypertrophy in Obstructive Sleep Apnea-Hypopnea Syndrome (OSAHS). Methods. Forty-four patients with OSAHS underwent tongue base resection in the last 2 years. Twenty patients with a 10-month minimum follow-up were evaluated. The anatomic details of 3 tongue bases dissected from above are illustrated. Results. The cadaveric study shows that no constant landmarks are identifiable, with no significant neurovascular structures present in the midline. Clinically, transoral robotic surgery (TORS) for the tongue base was feasible, with no major complications and satisfaction of the majority of patients. Mean apnea hypopnea index (AHI) improvement was SD, mean Epworth Sleepiness Scale (ESS) improvement was SD. Conclusion. Tongue base hypertrophy can be safely and effectively managed by TORS in OSAHS. Our midterm data are encouraging and worthy of further evaluation. VC 2011 Wiley Periodicals, Inc. Head Neck 34: 15 22, 2012 Keywords: robotic surgery; tongue base; OSAHS; sleep apnea; transoral Obstructive Sleep Apnea-Hypopnea Syndrome (OSAHS) is a critical social problem which seriously affects patients quality of life (QOL); it is also known as an independent risk factor for hypertension, 1 myocardial infarction, 2 and stroke. 3 OSAHS, when related mainly to severe retrolingual obstruction, is a challenging task for the physician, especially from a surgical point of view; minimal invasive techniques are an option in mild cases but totally Correspondence to: I. Dallan VC 2011 Wiley Periodicals, Inc. insufficient with massive bulky tissues. Minimally invasive robotic approach (transoral robotic surgery [TORS] performed with Intuitive da Vinci) has a promising future in patients with tongue base hypertrophy OSAHS, as we demonstrated in our preliminary experience, 4 but we believe that its clinical application should be performed with controlled studies; we think that tongue base management by means of TORS still remains a complex surgical task and needs a different anatomic orientation, even if resection of the tongue base for oncological purposes has already been reported previously. 5 Revision of data from the literature 4,6,7 seems to confirm the good tolerability of the procedure, and the complication rate is dependent on the specific procedure and not related to the use of the robotic techniques. Given the small amount of data available on this topic in the literature, we provide our personal anatomic and clinical experience, give a different anatomic perception of the tongue base, and discuss the results that confirm the tolerability and efficacy of this technology in patients with tongue base hypertrophic OSAHS. MATERIALS AND METHODS Anatomic dissection was performed in 3 injected fresh cadaver heads to better elucidate the robotic perspective of the tongue base anatomy. The dissection work was conducted at the Department of Anatomy of the Medical University of Wien by the same authors (I.D. and P.C.). Endoscopes with different angles (30,45, and 70 ) were used to reproduce a superior to inferior perspective of the anatomy of the tongue base. Forty-four patients with OSAHS with severe hypertrophy of the tongue base were treated by means of Transoral Robotic Surgery in Obstructive Sleep Apnea-Hypopnea Syndrome HEAD & NECK DOI /hed January

2 transoral robotic reduction at the ENT Unit of the Ospedale Pierantoni, Forlì. Inclusion criteria were previously reported. 4 Only patients with a minimum follow-up of 10 months were considered in this retrospective evaluation. This period was chosen to demonstrate the good stability of the results. Therefore, the study group was composed of 20 patients (20 65 years old), with 10 of these patients having been included in a previous report. 4 All patients were informed about the possible alternatives, both medical and surgical, and gave their consent to the procedure. Tongue base management was associated with other procedures in all but 2 patients. All patients underwent a standard surgical tracheotomy as the first surgical step. TORS was carried out by the same team (C.V. and F.M.) with an Intuitive da Vinci robot. The operative setting was the same as that described by O Malley 5 for the tongue base neoplasms. Strictly technical aspects have been published previously. 4 Anasogastric tube was inserted in the first 3 patients only. Clinical histories, awake and sleep endoscopy video recordings, imaging, preoperative and postoperative polysomnographic data, biometrics and psychometrics, including Epworth Sleepiness Scale (ESS) and satisfaction, were all collected and analyzed. Satisfaction was evaluated by means of a visual analogue scale (VAS; 0% to 100%), where 0% means no satisfaction at all, and 100% means complete satisfaction. To describe the pattern of collapse of the upper airway, we used our grading system 8 and we tried to tailor surgery, as much as possible, to the needs of the patient. The length of hospitalization, swallowing recovery time, and the pain profile were also studied postoperatively together with the complication rates. Technical aspects (duration of the procedure, robotic setup time, blood loss, and total anesthetic time) were also collected and analyzed. Polysomnographic (PSG) evaluation was performed by means of analysis of level 3 unattended sleep, based on the Associazione Italiana di Medicina del Sonno (Italian Association of Sleep Medicine) guidelines for the selection of PSG studies. 9 The study met the approval of the Local Board of Ethics (Institutional Review Board of the Hospital Morgagni Pietrantoni, Forlì). Notes on Surgical Technique. The robot is set up on the right side of the patient. The eyes and teeth are protected by means of specific devices. After the insertion of a mouth gag, the da Vinci robotic arms are placed in the oral cavity. Visualization is achieved with a 30 high magnification, 3-dimensional endoscope. Surgery begins with the visualization of the epiglottis to orientate the surgeon. Then a piecemeal resection of the tongue base is performed using a stepby-step approach. First the medial and paramedial portions of the tongue base are addressed and then the lateral parts. In this way, it is possible to identify and preserve the noble structures. At the end of the procedure, the surgical field was covered by FloSeal gel to enhance hemostasis. Statistical Methods. To identify the cutoff value for the relative gain, it is mandatory to understand if there has been a complete success, and so the receiver operating characteristic (ROC) curve was used. A univariate analysis with the use of a Wilcoxon test was performed by comparing pretreatment and posttreatment median values of apnea hypopnea index (AHI), ESS, and low saturation of O 2 (Sat O 2 ). Continuous variables were reported as mean (SD) and median (interquartile range). All tests were considered significant with p <.05. StatView 5 release was used for processing the data. RESULTS Twenty patients were included in the study. Eight of these patients had previously undergone some form of surgery. The procedure was completed successfully in all the patients; no shift to open procedures was necessary. Pretreatment and posttreatment average and median values of AHI, ESS, and Low Sat 0 2 are given in Table 1. By comparing pretreatment and posttreatment medians, by means of a Wilcoxon test, a statistical significance was demonstrated for all the parameters. These data are summarized in Table 2. The power of the test was 0.8. No serious complications were observed in our series. Minor bleeding, stopped with conservative measures, was observed in 3 patients. No revision surgery was deemed necessary in any case. One patient developed a severe pharyngeal edema, which was treated in a conservative fashion. In 2 patients, a subcutaneous emphysema was seen, which had a spontaneous resolution in a few days. No patients complained of impaired swallowing after the procedure (this parameter was only evaluated clinically). Regarding weight, there was no significant change in body mass index (BMI) before or after treatment; only 1 patient was obese before surgery. All patients but 2 were satisfied with the procedure. Regarding operative aspects: mean blood loss was ml; mean robotic surgical time was SD minutes, and mean setup time was SD minutes. The mean preoperative AHI was SD and the mean preoperative ESS was SD, whereas the postoperative averages of these parameters were SD and SD, respectively. Preoperative median values of AHI and ESS were, respectively, 31 and 11.5, whereas postoperative medians were 12.5 and 8 for AHI and ESS, respectively. In 1 patient, there was a worsening of AHI (patient 10). However, we observed an improvement in ESS in this patient and lowest Sat O 2. Detailed data referring to the patients are summarized in Table 3 and Transoral Robotic Surgery in Obstructive Sleep Apnea-Hypopnea Syndrome HEAD & NECK DOI /hed January 2012

3 Table 1. Pretreatment and posttreatment average and median values of AHI, ESS, and Low Saturation O 2. AHI pre AHI post RG AHI ESS pre ESS post RG ESS SAT pre SAT post Mean SD Median Abbreviations: AHI, apnea hypopnea index; pre, pretreatment; post, posttreatment, RG, relative gain; ESS, Epworth Sleepiness Scale; SAT, saturation; Pre, before treatment; post, posttreatment; RG AHI, (AHI pre-ahi post)/ahi pre 100; RG ESS, (ESS pre-ess post)/ess pre 100. To better evaluate the results from a clinical point of view, and to reduce the confounding use of numbers, we introduced the concept of the relative gain (RG; RG:[Xpre-Xpost]/Xpostx100). In this way, based on the RG, we have a more adequate evaluation of the real improvement of the patient but not a satisfactory definition of who is cured or not. We considered completely cured patients with a posttreatment AHI and ESS 10. Consequently, we decided to design an ROC curve to identify a cutoff value that allows the separation of the cured patients from the not cured patients. By means of an ROC curve, it is possible to evaluate the correlation between sensitivity and specificity of the RG test evaluating different values of cutoff by reporting the proportion of the true-positive and of the false-negative in a graphic. By evaluating the curve and by calculating the area below, it is possible to understand the discriminating capacity of the test; the best cutoff value available was RG AHI ¼ 38 and RG ESS ¼ 27. In Figure 1 and Figure 2, ROC curves are given (Figure 1-AHI; Figure 2-ESS). Regarding AHI, by using the RG cutoff value of 38, we could divide the study group in 2 parts (cured, RG AHI 38; not cured, RG AHI <38). By using this cutoff value, the cured patients were 14 (70%), whereas those considered not cured were 6 (30%). Regarding ESS by using the RG cutoff value of 27, we could divide the study group in 2 parts (cured, RG ESS 27; not cured, RG ESS <27). By using this cutoff value, the cured patients were 18 (90%), whereas those considered not cured were 2 (10%). As a whole, we had 12 completely cured patients (60%). Anatomic Considerations. The base of the tongue has a rich vascular supply from the lingual artery. Normally there is a good collateral circulation from the facial artery. With respect to a traditional lateral dissection, the superior to inferior dissection of the tongue base is challenged by the absence of constant anatomic landmarks. Therefore, the identification of critical neurovascular structures is more complex. The medial region of the tongue base is without major vessels. There are numerous small branches from the lingual artery approaching the midline. These can be used as a safe plane to remind the surgeon to be extremely careful when dissecting deeper. Significant vessels are located laterally and inferiorly. The dorsal lingual artery is the major branch that arises from the lingual artery, usually below the hyoglossus muscle. At the level of the hyoid bone, it is located above it and medial to the hypoglossal nerve. Inferiorly located, with regard to the artery, lies the lingual vein, which in turn accompanies the hypoglossal nerve. DISCUSSION OSAHS is an underestimated but serious health problem with high social impact. Surgery and ventilation represent the main therapeutic tools; secondary approaches include oral appliances and recommendation to lose weight. Surgery, to be effective, must be correctly selected and performed and, most importantly, proper procedures must be tailored to the effective needs of the single patient. Therefore, the understanding of the pattern of collapse in each patient is critical for successful surgery. When the main obstruction is located at the level of the tongue base, surgery becomes a great challenge for both the surgeon and patient due to abundant hypertrophic tissue. Given the fundamental functional role of the tongue base, with its critical physiological functions, tongue base surgery can be burdened with relevant complications that surgeons should always keep in mind. Data from literature show that experiences with open surgical approaches in tongue base hypertrophy management are scanty, limited to really few experiences, and associated with troublesome complications. 10,11 On the other hand, minimally invasive techniques, like radiofrequency surgery, have been proposed in mild cases, but they are totally inadequate in severe obstructions, as described in our series (Figure 3). Transoral laser tongue base resection has currently been abandoned in many parts of the world due to its technical difficulty, its highly required surgical skills, and its significant postoperative pain. 16 The robotic technique seems to offer significant advantages in such a contest. By means of multiplanar tissue transection, at any angle it enhances the ability of the surgeon in managing this complex region 5 and, with respect to traditional open approaches, robotic Table 2. Pretreatment and posttreatment comparison based on different parameters. Median AHI PRE vs Median AHI POST p ¼.0001 Median ESS PRE vsmedian ESS POST p ¼.0003 Median LowSatO 2 PRE vs Median LowSatO 2 POST p ¼.0004 Abbreviations: AHI, apnea hypopnea index; PRE, pretreatment; POST, posttreatment; ESS, Epworth Sleepiness Scale; LowSatO2, low saturation of O2. Transoral Robotic Surgery in Obstructive Sleep Apnea-Hypopnea Syndrome HEAD & NECK DOI /hed January

4 Table 3. Clinical and treatment data. Patient Previous surgery failure Procedure TRST TRT SR, d NGFT removal, d Tracheo removal, d Discharge VAS Blood loss, ml Complications 1 TBRþSPLþITR IX day: small bleeding stopped spontaneouslyþ H2O2 (few minutes) 2 TBR IX day: small bleeding stopped spontaneouslyþ H2O2 (about 1 2 h) 3 UVPþTSþITI TBRþSGPþSPLþ ITRþUPPP Pharyngeal edema occurring in the post-surgical time 4 TBRþSGP UVPþTSþSPLþ ITI TBRþSGPþ ITRþUPPP TBRþSGP TBRþSGPþ SPLþITR VII day: small bleeding stopped spontaneouslyþ H2O2 (few minutes) 8 TBRþSGPþSPLþ ITRþ UPPPþ Etmoidectomy SPL TBRþSGPþ ITR UPPPþTS TBR UPPPþSPLþITR TBRþEpiglottopexy VI day: subcutaneous emphysema recovered spontaneously 12 UPPPþTSþSPL TBRþSGPþITRþUPPPþTS ITR TBRþSGP TBRþSGPþSPLþITRþUPPPþTS ITR TBRþSGPþUPPPþTSþITR VII day: subcutaneous emphysema recovered spontaneously 16 TBRþSGPþSPLþITR TBRþSGPþUPPPþ TS TBRþSGPþUPPPþ TS TBRþSGP TBRþSGP Abbreviations: TBR, tongue base resection; SPL, Septoplasty; ITR, inferior turbinate reduction; SGP, supraglottoplasty; TS, tonsillectomy; UPPP, uvulopalatopharyngoplasty; UVP, Uvuloplasty; TRST, total robotic setting time; TRT, total robotic time; SR, swallowing recovery; NGFT, nasogastric feeding tube; VAS, visuoanalogic scale. 18 Transoral Robotic Surgery in Obstructive Sleep Apnea-Hypopnea Syndrome HEAD & NECK DOI /hed January 2012

5 Patient no. Age Sex IC, cm Table 4. Pre- and post-treatment functional data. Friedman score AHI Lowest Sat 0 2 ESS BMI FPPS FTS Pre Post Pre Post Pre Post Pre Post Satisfaction 1 48 M M M F M F M M M / M M M M M M M M M M M Abbreviations: IC, intrinsic distance; FPPS, Friedman Palatal Position Score; FTS, Friedman Tonsil Score; AHI, apnea/hypopnea Index; Sat 02, saturation of O2; ESS, Epworth Sleepiness Scale; BMI, Body Mass Index; Pre, pretreatment; Post, posttreatment. management of the tongue base seems to be very well tolerated. 4,6,7 Our data seem to confirm that tongue base resection by means of TORS is feasible and well tolerated. The postoperative pain is low and we observed minimal modification of BMI after surgery. Feasibility and safety of TORS has been previously confirmed for oropharynx, hypopharynx, and supraglottic surgery. 5,17 Oncological results in oropharyngeal cancer are encouraging 5,18 and newer clinical robotic applications FIGURE 1. Receiver operating characteristic (ROC) curve regarding apnea hypopnea index (AHI). RG, relative gain; CI, confidence interval. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.] FIGURE 2. Receiver operating characteristic (ROC) curve regarding Epworth Sleepiness Scale (ESS). RG, relative gain; CI, confidence interval. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.] Transoral Robotic Surgery in Obstructive Sleep Apnea-Hypopnea Syndrome HEAD & NECK DOI /hed January

6 FIGURE 3. Radiologic (A) and clinical (B) preoperative view of severe tongue base hypertrophy. (C) and (D) Postoperative result. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.] are reported regularly, 19,20 thus showing a growing interest in this new technology. Operating time and blood loss have proven to be comparable with an open surgical approach or endoscopic laser resection. 18 On the other hand, the 3D visualization offers a superb vision of the surgical field, thus increasing the orientation of the surgeon. Our experience with more than 60 cases (not all for OSAHS), confirms these findings in all the cases treated. The blood loss in our series was minimal ( ml). With greater experience, the operating time (o.t.) and also the setting time (s.t.) improved (o.t SD minutes; s.t SD minutes). Additionally, we strongly underline the critical role of a sound knowledge of endoscopic/robotic anatomy of the tongue base. Traditional surgical landmarks are useless in robotic surgery, so only a dedicated cadaveric dissection can provide a useful 3D anatomic orientation. Our anatomic experience showed that tongue base tissue offers no safe or reproducible landmarks, with the exception of a rich vascular arterial network approaching the midline that was constantly present. Theoretically, this network could be considered as an anatomic plane above which major vessels and nerves are not present. In real surgery, its identification is not easy to obtain; we strongly advise performing further deeper dissection strictly on the midline where no major neurovascular structures are present. Successively midline identification of the hyoid bone is safe, and above it, in a lateral position, the lingual artery, covered by the hyoglossal muscle, can be discovered. Lateral to this muscle, the hypoglossal nerve with its comitant vein can be observed (Figure 4). Thus, from a technical point of view, the dissection should start in the midline and be performed carefully in a medial to lateral direction. We underline that in real surgery the ability to identify the structures is even worse given the frequent presence of hypertrophic lymphatic tissue. We maintain that strict collaboration with the radiologist and a careful discussion, case by case, is advisable. In this article, we report our midterm experience (all patients with a follow-up of at least 10 months) with robotic resection of the tongue base. We underline that we do not want to propose our technique as standard for such cases, but that in expert hands such a technique is effective on many levels, with amelioration of respiratory and neurocognitive parameters and of quality of life (Table 2). We strongly emphasize that all our patients except 2 were extremely satisfied with the 20 Transoral Robotic Surgery in Obstructive Sleep Apnea-Hypopnea Syndrome HEAD & NECK DOI /hed January 2012

7 FIGURE 4. Anatomic 3-dimensional drawing and its endoscopic correlation focused on anatomic details of the tongue base from a surgical-robotic point of view. DLA, deep lingual artery; E, epiglottis; GHM, genioglossus muscle; HB, hyoid bone; HGM, hyoglossus muscle; HN, hypoglossal nerve; LA, lingual artery; dlas, dorsal branches of the lingual artery; LV, lingual vein; MHM, mylohyoideus muscle; SLA, sublingual artery; TB, tongue base; tb, tonsillar brach of the lingual artery. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.] procedure. Mean AHI improvement was SD. In 1 patient, there was a worsening of AHI, whereas all patients presented an improvement of ESS (mean ESS improvement was SD) and lowest Sat O 2 (mean lowest Sat O 2 improvement was SD). We underline that patient 9 at the second PSG evaluation presented an improvement of AHI, thus in disagreement with what was previously reported. 4 Maybe with time, the scar evolution has led to a stiffness of the tongue base and so to a significant improvement of AHI. The real difficulty is to determine if these patients improved in a statistically significant manner or were cured in a statistically significant manner, which is not the same thing. To reduce the difficulty in interpreting the results, we decided to offer a more comprehensive statistical evaluation, given the fact that a simple improvement in AHI or ESS cannot be a real parameter in discriminating success from failure. We define a patient as cured when both AHI and ESS are 10. For example, a patient who passes from AHI90 to AHI42 presents an important improvement but the disease is still present and severe. In other words, the patient is absolutely not cured. On the other hand, if patients are simply divided into cured and not cured based on AHI or ESS, the statistical evaluation misses the true implication that the procedure is significantly effective in improving AHI (for example if AHI passes from 91 to 12). Thus, to reduce this confusing use of numbers, we introduced the concept of the relative gain-rg and the ROC curve. Accordingly, when considering the AHI parameter alone (cardiovascular parameter), 14 patients can be considered cured (70%), whereas if we consider ESS alone (neurocognitive parameter), 18 patients are to be considered cured (90%). Twelve patients (60%) would be completely cured (both AHI and ESS). We strongly underline that these patients are not to be considered successes, they are cured! Therefore, we maintain that our results, although needing confirmation in larger series, are worthy of serious consideration. We emphasize the fact that conventional nose surgery may be associated at the same time and with the same setting, if required. Oropharyngeal and epiglottic surgery can be performed robotically or conventionally. At the moment, we maintain that tracheotomy placement is advisable, even if we are evaluating its real necessity. In our overall experience (>60 patients), there were no true problems necessitating a tracheotomy; notwithstanding, its presence would be very useful in the case of bleeding. All the patients were decannulated between day 4 and 13 after surgery. The feeding tube was placed only in the first 3 patients and all the patients regained a satisfactory ability to swallow within 2 weeks: patient 4 was allowed a liquid diet from the second day without a nasogastric tube and with no trouble. As a whole, our data seem to demonstrate the good tolerability and efficacy of tongue base resection by means of TORS. Although a tracheotomy was carried out in every patient, the subjective perception of the patients of the procedure was absolutely positive, with a high level of satisfaction in all patients except 2; those who were unsatisfied were patients in whom surgery did not lead to an expected improvement of QOL; this happened regardless of the presence or not of a tracheotomy. We Transoral Robotic Surgery in Obstructive Sleep Apnea-Hypopnea Syndrome HEAD & NECK DOI /hed January

8 would like to emphasize that, although OSAHS cannot be compared to cancer, its impact on QOL and on life itself can be very severe. 21 Also, in cases of severe tongue base hypertrophy, minimally invasive techniques are absolutely inadequate to control the disease significantly and, in this sense, no serious alternative to a surgical tongue base resection, except ventilation, exists. CONCLUSIONS Tongue base resection by means of robotic techniques is feasible and well tolerated in patients with OSAHS. Furthermore, based on our data, when properly selected, it seems to be effective and results are stable after 10-months follow-up. The procedure is safe, easy to learn, and associated with complications of minimal significance. A larger experience, possibly not limited to a few centers and maybe included in controlled trials, will tell us the real utility of this surgical procedure for the future. Acknowledgment. We thank Mrs. Diana Hearn for her help in translation and revising the manuscript. REFERENCES 1. Peppard PE, Young T, Palta M, Skatrud J. Prospective study of the association between sleep-disordered breathing and hypertension. N Engl J Med 2000;342: Marin JM, Carrizo SJ, Vicente E, Agusti AG. Long-term cardio-vascular outcomes in men with obstructive sleep apnoeahypopnoea with or without treatment with continuous positive airway pressure: an observational study. Lancet 2005;365: Yaggi HK, Concato J, Kernan WN, Lichtman JH, Brass LM, Mohsenin V. Obstructive sleep apnea as a risk factor for stroke and death. N Engl J Med 2005;353: Vicini C, Dallan I, Canzi P, Frassineti S, La Pietra MG, Montevecchi F. Transoral robotic tongue base resection in obstructive sleep apnoea-hypopnoea syndrome: a preliminary report. ORL J Otorhinolaryngol Relat Spec 2010;72: O Malley BW Jr, Weinstein GS, Snyder W, Hockstein NG. Transoral robotic surgery (TORS) for base of tongue neoplasms. Laryngoscope 2006;116: Hockstein NG, O Malley BW Jr. Transoral robotic surgery. Oper Tech Otolaryngol Head Neck Surg 2008;19: Weinstein GS, O Malley BW Jr, Desai SC, Quon H. Transoral robotic surgery: does the ends justify the means? Curr Opin Otolaryngol Head Neck Surg 2009;17: Vicini C, Corso RM, Gambale G. Sleep endoscopy e sistema NOHL. In: Vicini C, editor. Chirurgia della Roncopatia. Eureka Editore: Lucca; pp Commissione paritetica AIPO-AIMS: Linee Guida di Procedura Diagnostica nella Sindrome delle Apnee Ostruttive dell adulto. Rass Patol Appar Respir 2001;16: Chabolle F, Wagner I, Blumen MB, Séquert C, Fleury B, De Dieuleveult T. Tongue base reduction with hyoepiglottoplasty: a treatment for severe obstructive sleep apnea. Laryngoscope 1999;109: Sorrenti G, Piccin O, Mondini S, Ceroni AR. One-phase management of severe obstructive sleep apnea: tongue base reduction with hyoepiglottoplasty plus uvulopalatopharyngoplasty. Otolaryngol Head Neck Surg 2006;135: Stuck BA, Maurer JT, Verse T, Hörmann K. Tongue base reduction with temperature-controlled radiofrequency volumetric tissue reduction treatment of obstructive sleep apnea syndrome. Acta Otolaryngol 2002;122: Fernández-Julián E, Muñoz N, Achiques MT, Garcia-Pérez MA, Orts M, Marco J. Randomized study comparing two tongue base surgeries for moderate to severe obstructive sleep apnea syndrome. Otolaryngol Head Neck Surg 2009;140: Babademez MA, Ciftci B, Acar B, et al. Low-temperature bipolar radiofrequency ablation (coblation) of the tongue base for supineposition-associated obstructive sleep apnea. ORL J Otorhinolaryngol Relat Spec 2010;72: Li KK, Powell NB, Riley RW, Guilleminault C. Temperature-controlled radiofrequency tongue base reduction for sleep-disordered breathing: long-term outcomes. Otolaryngol Head Neck Surg 2002;127: Woodson BT. Transoral midline glossectomy and lingualplsty. In: Fairbanks DNF, Mickelson SA, Woodson BT, editors. Snoring and Obstructive Sleep Apnea. 3rd edition. Philadelphia, PA: Lippincott Williams & Wilkins; pp Weinstein GS, O Malley BW Jr, Snyder W, Hockstein NG. Transoral robotic surgery: supraglottic partial laryngectomy. Ann Otol Rhinol Laryngol 2007;116: Weinstein GS, O Malley BW Jr, Snyder W, Sherman E, Quon H. Transoral robotic surgery: radical tonsillectomy. Arch Otolaryngol Head Neck Surg 2007;133: Mukhija VK, Sung CK, Desai SC, Wanna G, Genden EM. Transoral robotic assisted free flap reconstruction. Otolaryngol Head Neck Surg 2009;140: Selber JC, Robb G, Serletti JM, Weinstein G, Weber R, Holsinger FC. Transoral robotic free flap reconstruction of oropharyngeal defects: a preclinical investigation. Plast Reconstr Surg 2010;125: Friedman M, Wilson M. Evidence based sleep medicine: are we there yet? Sleep Med Rev 2008;12: Transoral Robotic Surgery in Obstructive Sleep Apnea-Hypopnea Syndrome HEAD & NECK DOI /hed January 2012