Radiofrequency Surgery of the Soft Palate in the Treatment
Transcription
Radiofrequency Surgery of the Soft Palate in the Treatment
SLEEP DISORDERED BREATHING Radiofrequency Surgery of the Soft Palate in the Treatment of Snoring. A Placebo-Controlled Trial. Boris A. Stuck, MD; Alexander Sauter, MD; Karl Hörmann, MD; Thomas Verse, MD; Joachim T. Maurer, MD Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Mannheim, Mannheim, Germany ner with 10 cm visual analogue scales. 23 patients completed the study; 12 received RF-surgery and 11 received placebo. Snoring scores did not change in the placebo group (8.4±1.6 to 8.0±2.3) while improving in the RF-group (8.1±1.3 to 5.2±2.4). The difference between the groups was statistically significant (p<0.05). Conclusion: RF-surgery was significantly better than placebo, although the reduction in snoring was only moderate in our group of patients. This study underlines the necessity for well-controlled clinical trials in the treatment of snoring. Keywords: Radiofrequency surgery, soft palate, snoring Citation: Stuck BA; Sauter A; Hörmann K et al. Radiofrequency surgery of the soft palate in the treatment of snoring. A placebo-controlled trial. SLEEP 2005;28(7): 847-850. Study Objectives: Recent publications have demonstrated a reduction in snoring with radiofrequency (RF) surgery of the soft palate. Yet so far, all published data has been based on non-controlled trials. Design: Aim of this study was to assess the efficacy of RF surgery of the soft palate in a randomized, placebo-controlled trial. Setting: Outpatients department at university hospital, department of otorhinolaryngology Patients: 26 patients with primary snoring (AHI<15, BMI<35). Interventions: Patients were treated with temperature-controlled RF surgery of the soft palate under local anesthesia. In accord with a randomization protocol they received 2 sessions of RF surgery (total amount of energy: 3.300 Joule) or placebo (insertion of device needle without energy delivery). Measurements and Results: Snoring was evaluated by the bed part- INTRODUCTION: METHODS IN CONTRAST TO OBSTRUCTIVE SLEEP APNEA, NO GENERALLY ACCEPTED GOLD STANDARD IS AVAILABLE FOR THE TREATMENT OF PRIMARY SNORING. IN addition to non-invasive treatment modalities such as intraoral devices, soft palate surgery has become a widespread treatment option. Due to its minimally invasive character, radiofrequency (RF) surgery of the soft palate has received increased attention. A recently published review of the literature demonstrated that all published trials document a significant improvement of primary snoring and minimal postoperative pain while postoperative complication rates were low in the majority of these studies.1 Nevertheless, the above mentioned review also pointed out the major limitation of these studies, namely the lack of control groups. Control groups are particularly important in studies investigating therapeutic effects in primary snoring, as no reliable objective measurements are available and clinical efficacy is usually assessed with bed-partner questionnaires. Aim of our study was to assess the efficacy of RF-surgery of the soft palate in the treatment of primary snoring in a randomized, placebo-controlled trial. The study protocol was approved by the local ethics board of the Faculty of Clinical Medicine Mannheim of the University of Heidelberg; written informed consent was obtained from all the participating subjects. Patients with primary snoring between the age of 18 and 65 and a maximum BMI of 35 were included if they had complained about socially disruptive snoring and asked for surgical treatment. Non-invasive treatment alternatives including intraoral devices were offered to all our patients. Patients were only considered for soft palate surgery if they were otherwise healthy and no professional voice users, if they were not complaining about excessive daytime sleepiness, and if obstructive sleep apnea had been ruled out with either polysomnography or ambulatory polygraphic measurements. With respect to the polysomnographic or polygraphic results, a maximum apnea-hypopnea-index or oxygen desaturation index of 15 was used as inclusion criteria. Regarding the individual anatomy of our patients, RF-surgery of the soft palate was offered in those cases where a relevant retrolingual obstruction or significant tonsilar hypertrophy was ruled out with clinical assessment including rigid endoscopy (awake patient). Concerning the evaluation of retrolingual obstruction due to potential tongue base hypertrophy the appearance of the epiglottic vallecula at the laryngeal endoscopy was the main criteria. Patients with relevant uvular hypertrophy and patients with previous soft palate surgery were also excluded. As no generally accepted objective airway assessment is available, the decision whether patients were ultimately suitable for RF-soft palate surgery was based on subjective clinical assessment. As stated above, the inclusion criteria were in accordance with the criteria for RF soft palate surgery described in the literature. Patients received two consecutive sessions of either temperature controlled RF-surgery (Somnoplasty®) or placebo on an out- Disclosure Statement This was not an industry supported study. Dr. Hörmann has received research support and equipment, including treatment devices, from Gyrus ENT. Drs. Stuck, Sauter, Verse, and Maurer have indicated no financial conflicts of interest. Submitted for publication December 2004 Accepted for publication March 2005 Address correspondence to: Boris A. Stuck, MD, Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Mannheim, 68135 Mannheim, Germany; Tel: +49 (0) 621 383 1600; Fax:+49 (0) 621 383 3827; E-mail: [email protected] SLEEP, Vol. 28, No. 7, 2005 847 Placebo-Controlled RF-Surgery for Snoring—Stuck et al patient basis under local anaesthesia. The Somnus® radiofrequency generator Model S2 (Gyrus ENT, Bartlett, USA) was used for the generation of temperature-controlled RF-energy. The surgical procedure itself was standardized. Three application sites were selected for the first session (600 Joule in the midline and two times 450 Joule approx. 1 cm lateral to the midline) and four application sites were chosen for the second session (4 times 450 Joule). In total, 3300 Joule were delivered in the RF-group. The target temperature was set to 85° C. Placebo treatment followed the same standardized protocol, including local anesthesia. In the placebo group, the device needle was inserted but no RF-energy was delivered. In both groups, patients did not receive any sedation or prophylactic antibiotics; corticosteroids were not used. Due to the local anesthesia and the minimal postoperative pain (minimal discomfort was also reported solely due to the insertion of the device needle), we do believe that patients were not able to determine whether they received RF-surgery or placebo. The procedure itself was performed by a single surgeon who was not the primary investigator; the surgeon adhered to a computer-generated randomization protocol. In accordance with an observer-blind study, the primary investigator was not informed about the results of the randomization process. The second session was performed 4 to 6 weeks after the first one. Follow up visits were scheduled 6 to 8 weeks after the second treatment session. Snoring was assessed with a 10 cm visual analogue scale. “No snoring” and “excessive snoring, bed partner leaves the room”were used as anchors. Functional parameters such as speech, taste, swallowing and pharyngeal irritation were also assessed using standard 10 cm visual analogue scales (VAS). No problems / not affected (0) and severe problem / severely affected (10) were used as anchors. Daytime sleepiness was assessed with the Epworth Sleepiness Scale. Table 1—Results of visual analogue scales for daytime sleepiness and snoring before and after treatment 23 patients completed the protocol; 3 patients were not available for follow-up. Mean age was 42.6±7.6 years (range: 27-60 years). 12 patients received RF-surgery according to the protocol, 11 received placebo. Mean snoring scores as assessed by the bed partner remained unchanged in the placebo group (mean score before surgery: 8.4 ± 1.6, after surgery: 8.0 ± 2.3), while it improved in the RF group from 8.1 ± 1.3 preoperative to 5.2 ± 2.4 postoperative. There was a statistically significant difference between the two groups regarding the changes in snoring (p=0.045). Daytime sleepiness improved minimally in the control group (preoperative ESS 5.2 ± 3.1, postoperative ESS 4.3 ± 2.7) while it improved to a slightly greater extent in the RF group (peroperative ESS 5.4 ± 4.6, postoperative ESS 3.9 ± 3.3). The differences between the two groups were not statistically significant (p=0.77). Results of snoring and daytime sleepiness are shown in Figures 1 and 2 and in Table 1. All the other parameters (speech, taste, swallowing, pharyngeal irritation) remained unchanged in both groups (all p>0.05, results see Table 2). Number Group 1 3 6 7 8 9 14 18 19 22 26 2 4 5 11 12 13 17 20 21 23 24 25 STATISTICS The statistical analysis was conducted at the Department of Statistics of the Faculty of Clinical Medicine Mannheim. The sample size for this study was calculated using the reported effects as summarized in our previously published review.1 Based on a 5% type I error (alpha-error) combined with a power of 90%, 12 patients per subgroup were considered as being necessary for the statistical analysis. In total, 26 patients were finally included in the trial in order to accommodate for possible drop-outs. Changes (after – before) in snoring and functional parameters (VAS) as well as in daytime sleepiness (ESS) results were calculated. Differences between groups were analyzed with the help of a non-parametric approach (2-sample rank sum, U-test). A pvalue of less than 0.05 was considered to be statistically significant. All computations were performed with the help of the SAS program (version 8.2). RESULTS ESS pre ESS post Snore pre Snore post Placebo Placebo Placebo Placebo Placebo Placebo Placebo Placebo Placebo Placebo Placebo 6 7 3 11 8 2 7 6 3 4 0 5 4 7 10 6 3 4 2 3 3 0 6.3 10 8.8 9.7 7.6 5.8 6.5 8 10 9.5 10 10 9.4 8.6 9.8 6.5 4.1 5.4 4.9 9.5 10 10 MV±SD 5.2±3.1 4.3±2.7 8.4±1.6 8.0±2.3 RF-surgery RF-surgery RF-surgery RF-surgery RF-surgery RF-surgery RF-surgery RF-surgery RF-surgery RF-surgery RF-surgery RF-surgery 7 3 5 7 2 14 14 1 1 2 7 2 7 3 3 4 2 9 11 1 1 1 3 2 8.8 9.6 8.8 10 8 8.2 8.9 7 7.7 5.8 7.6 6.3 4.8 1.1 5.2 3.5 9.7 4.2 8.6 6.5 5.7 6.6 4.6 2.3 MV±SD 5.4±4.6 3.9±3.3 8.1±1.3 5.2±2.4 DISCUSSION The present study investigated the effects of RF-surgery of the soft palate in patients with primary snoring in a placebo-controlled setting. This is the first time that a placebo-controlled study design was used in RF-surgery. Due to the minimally-invasive character of the procedure and the minimal postoperative pain when used at the soft palate, patients were not able to distinguish between placebo and RF surgery, therefore, a placebo treatment was possible. MV: mean values; SD: standard deviation; RF: radiofrequency SLEEP, Vol. 28, No. 7, 2005 848 Placebo-Controlled RF-Surgery for Snoring—Stuck et al Figure 2—Pre- and postoperative scores for daytime sleepiness in both groups Mean values ± SD, ESS: Epworth Sleepiness Scale Figure 1—Pre- and Postoperative Snoring Scores in Both Groups Mean values ± SD, VAS: visual analogue scales CONCLUSION Table 2— Results of visual analogue scales for functional parameters before and after treatment Parameter [VAS] pretreatment Placebo speech 1.0±1.4 swallowing 0.3±0.6 taste 0.4±0.5 pharyngeal irritation 0.8±0.9 postpretreatment treatment Placebo RF-group 0.7±1.1 0.4±0.8 0.3±0.5 0.4±0.6 0.4±0.6 0.3±0.7 0.6±1.4 1.1±1.0 RF-surgery of the soft palate for primary snoring is significantly more effective than placebo in reducing nightly snoring sounds. Nevertheless, snoring is not eliminated and only a moderate reduction could be achieved in our group of patients, although the sample size is relatively small which limits the significance of our conclusions. The costs of the procedure associated with single use devices are relatively high (250 Euro for a soft palate needle according to the distributor in Germany). Furthermore, a loss of efficacy over time has been documented at long term follow up studies. 2,8,12 The results of our study underline the necessity of well-controlled clinical trials to critically evaluate the various treatment options for primary snoring. posttreatment RF-group 0.3±0.5 0.4±0.5 0.3±0.4 1.5±1.8 VAS: visual analogue scale; RF: radiofrequency; mean values ± SD According to our results, two sessions of RF-surgery were significantly more effective than placebo in reducing socially disruptive snoring as assessed by a bed partner questionnaire. Nevertheless, the postoperative snoring scores in the RF-group were not satisfying. With regard to the current literature, a reduction of snoring to a postoperative snoring score below 3 is regularly considered as a successful treatment.2-7 Only two patients of our patients were successfully treated according to this definition. With respect to the current literature, our data supports the idea that RF-surgery of the soft palate leads to a reduction of snoring. Nevertheless, our postoperative snoring scores are not in accordance with most of the studies published and the results of our literature review.1 The postoperative score was comparable to selected studies only,8,9 where RF-surgery also lead to a significant reduction in snoring and was recommended as an effective procedure, although postoperative snoring scores were still at a relatively high level. This discrepancy can not be due to differences in the surgical protocol. Especially the total amount of energy applied and the total number of lesions were in accordance with the current literature as summarized in our literature review.1 Since all the patients in the RF-group reported an improvement after the first procedure and only minimal additional effects after the second one, further RF-treatments were not routinely offered. Placebo-controlled trials have only rarely been conducted in the field of primary snoring,10,11 the study of Larrosa et al. for laser-assisted uvulopalatoplasty being the only one for surgical treatments. With regard to the inoffensive nature of primary snoring, controlled clinical trials are necessary to critically evaluate the efficacy of the numerous treatments available. SLEEP, Vol. 28, No. 7, 2005 REFERENCES 1. 2. 3. 4. 5. 6. 7. 8. 9. 849 Stuck BA, Verse T, Hein G, Hörmann K, Maurer JT. Radiofrequency surgery of the soft palate in the treatment of snoring – a review of the literature. 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