Radiofrequency Tissue Volume Reduction of the Soft Palate in Simple Snoring

ORIGINAL ARTICLE Radiofrequency Tissue Volume Reduction of the Soft Palate in Simple Snoring

Craig A. Hukins, MD, FRACP; Ian C. Mitchell, MD, FRACS; David R. Hillman, MD, FANZCA

Background: Snoring is common and often associated Results: After treatment, there was a significant overall with social morbidity. Current therapies are generally un- improvement in the snoring visual analog score (7.5 ± 1.5 satisfactory, but radiofrequency tissue volume reduc- to 4.6 ± 2.5; PϽ.001), a small reduction in the proportion (RFTVR) palatoplasty offers a new approach. tion of sleep spent snoring at 50 to 60 dB (P = .03), and mild pain that was controlled with simple analgesia. There Objective: To assess the outcomes and morbidity as- were no long-term adverse effects. Individual response sociated with RFTVR palatoplasty. could not be predicted by demographic, polysomnographic, or cephalometric data. Treatment of the proxi- Design: Open, prospective trial. mal third of the soft palate was associated with fewer adverse effects but also seemed less effective than at the other Setting: Tertiary referral center. sites.

Patients: 20 adults with loud habitual snoring without Conclusions: (1) The RFTVR palatoplasty is well tol- clinically significant obstructive sleep apnea. erated with very low morbidity. (2) It is associated with subjective improvement in snoring in most patients. Interventions: Three treatments with RFTVR to the (3) Placement of lesions seems to influence outcome. middle, distal, and proximal thirds of the midline of the (4) The improvement is accompanied by a marginal soft palate. change in objective measurements, suggesting either an acoustic change independent of sound intensity or a pla- Main Outcome Measures: Clinical assessment (vi- cebo effect. (5) A randomized controlled trial is needed sual analog scores) before and after each treatment, poly- to further evaluate this therapy. somnography (with sound intensity measurements), and lateral cephalometry performed prior to the first treatment and 2 months following the final treatments. Arch Otolaryngol Head Neck Surg. 2000;126:602-606

NORING IS a common prob- Recently it has been suggested that lem, with 81% of men aged 40 radiofrequency tissue volume reduction to 65 years snoring for more (RFTVR) applied to the soft palate might than 10% of the night, and 22% offer a safe, effective alternative.6 This for more than 50% of the night procedure involves thermocoagulation Son home monitoring.1 Current therapies for of tissue by low-intensity radiofre- simple snoring are unsatisfactory. Surgical quency signal. The low temperature modalities such as laser-assisted uvulo- involved (60°C-90°C) results in a local- plasty or uvulopalatopharyngoplasty are ized thermal lesion with minimum associated with significant morbidity.2,3 injury to surrounding tissue. It has been Other treatments require ongoing use used in other fields for many years, rather than offering the prospect of a cure. including ablation of accessory cardiac Dental devices are often effective but are conduction pathways, treatment for associated with substantial adverse ef- benign prostatic hyperplasia, and tri- From the Departments of fects.4 Continuous positive airway pres- geminal gangliotomy for neuralgia. The Pulmonary Physiology (Drs Hukins and Hillman) sure is a very effective therapy, but pa- rationale for use of the therapy to treat and Ear Nose and Throat tient compliance and acceptance is poor, snoring is that resorption of the thermo- Surgery (Dr Mitchell), Sir particularly when snoring is not accom- coagulated tissue and subsequent scar- Charles Gairdner Hospital, panied by obstructive sleep apnea of at least ring stiffens and shortens the soft pal- Nedlands, Australia. moderate severity.5 ate, reducing its tendency to vibrate.

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©2000 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/26/2021 PATIENTS AND METHODS analyzed according to the standards of the American Tho- racic Society.9 Following this initial evaluation, subjects received 3 Twenty adult patients with socially problematic snoring were RFTVR treatments to the soft palate at intervals of at least selected from among those presenting to a sleep disorders 2 weeks. The procedures were performed in a surgical re- or ear, nose, and throat clinic. Subjects needed to meet the covery room. Topical lidocaine (4%) followed by submu- following criteria: age 18 years or older, bothersome snor- cosal infiltration of 2% lidocaine with epinephrine were used ing, maximum snore intensity of 50 dB or greater, and only as local anesthetics. A radiofrequency generator (Somnus simple snoring or mild obstructive sleep apnea (apnea- Medical Technologies, Sunnyvale, Calif) and a hand-held hypopnea index of Յ15). Subjects were excluded if there electrode were used to deliver 650 J (constant electrode tem- was a history of neurological, swallowing, or unstable psy- perature of 85°C) to the midline of the soft palate. Treat- chiatric disorders, obesity (body mass index [BMI or Quete- ments were provided to the middle, distal, and proximal let index, calculated as weight in kilograms divided by the thirds of the soft palate successively. Clinical assessment square of the height in meters], Ͼ32), or if there was a his- was performed at days 3 and 7 after each treatment. A VAS tory of previous pharyngeal surgery (excluding tonsillec- was used to evaluate pain, speech, and swallowing after tomy or adenoidectomy). Informed consent was provided therapy. The subjects were asked to rate the following char- by all subjects. acteristics: pain, on a continuous scale from none to severe (pain that does not resolve even after analgesic medi- PROTOCOL cation); the effect on speech, on a continuous scale from none to severe (difficulty talking); and difficulty swallow- The study was an open, prospective design and was ap- ing, on a continuous scale from none to severe (unable to proved by a hospital ethics and research committee. Prior swallow without pain even after analgesic medication). to first treatment, clinical assessment (visual analog scores Subjects were reevaluated 8 weeks after the final treat- [VASs] of snoring [partner assessment] and of sleepiness ment. Clinical assessment was again made using the VAS and the Epworth sleepiness score7), polysomnography (sleep of snoring intensity (partner assessment) and of sleepi- staging, oronasal flow [thermistor], chest and abdominal ness and the Epworth sleepiness score.7 Polysomnogra- motion [inductance plethysmography; Respitrace, Ardsley, phy and lateral cephalometry were repeated. NY], sound intensity monitoring [Model NA-24; Rion, To- kyo, Japan]), and lateral cephalometry were performed. The ANALYSIS VAS of snoring (range, 0-10) was derived from a rating made on a continuous scale from none to very intense (partner Data are presented as mean ± SD. Analysis was performed leaves bedroom). The VAS of sleepiness was derived from using a statistical software package (SigmaStat; Jandel Cor- a scale ranging from no tendency to sleep to constantly fall- poration, Oxon, England). Clinical and cephalometric data ing asleep during the day. Polysomnography was per- were compared before and after treatment by a paired t test. formed in a small room (4 ϫ 4 ϫ 2.7 m) that was rela- Polysomnographic outcomes were compared by a Mann- tively nonabsorbent for sound. Using an extension cable, Whitney rank sum test. The relationships of baseline de- the omnidirectional microphone of the sound intensity me- mographic, polysomnographic, and cephalometric data to ter was set in a fixed position relative to the sound source, improvements in subjective snoring were examined by being 1 m above the subject’s head, in accordance with our forward stepwise linear regression. PϽ.05 was considered previously published methods.8 The polysomnogram was significant.

Thus far, there has been limited evaluation of this posttreatment, 6.7 ± 4.0) or sleepiness VAS (baseline, new therapy. The purpose of this study is to use subjec- 3.0 ± 2.0; posttreatment, 2.6 ± 2.2). Polysomnographic tive (patient and partner reports) and objective (sound data and BMI before and after treatment are given in intensity monitoring) means to evaluate the potential ef- Table 1. ficacy of RFTVR of the soft palate to treat simple snoring and to examine its adverse effects and complica- SUBJECTIVE SNORING tions. Because we are interested in the effect of placement of the lesions, we designed the study so that the lesions There was a significant improvement in subjective snor- were made in a fixed order to 3 fixed locations, and as- ing for the group (from 7.5 ± 1.5 to 4.6 ± 2.5; PϽ.001). sessed efficacy after each treatment. While 18 of 20 patients reported some improvement in subjective snoring (Figure 1), only 8 patients reported RESULTS an improvement of at least 50%. Improvements in subjective snoring for the group were noted after the first SUBJECTS (middle third of the soft palate) and second (distal third) treatments but not after the third (proximal third) Sixteen of 20 patients were men (mean ± SD age, (Figure 2). 43.2 ± 11.1 years). A mean ± SD of 650 ± 7.18 J was delivered at each treatment, with an average duration of SNORING INTENSITY 2.43 ± 0.52 minutes. The mean interval between treatments was 26.9 ± 12.1 days. There was no significant There was a statistically significant but clinically irrel- change in Epworth sleepiness score (baseline, 8.1 ± 4.0; evant increase in the maximum measured snoring inten-

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Before and After Treatment† 9 P = .04

Not 8 Characteristic Baseline Posttreatment Significance Significant

Body mass index† 27.1 ± 2.8 27.5 ± 3.2 NS 7 Apnea-hypopnea index, 3.3 ± 3.1 6.6 ± 8.1 NS per sleep hour 6 Arousal index, 19.4 ± 7.9 19.2 ± 9.6 NS per sleep hour 5 Sleep efficiency 82.6% ± 9.6% 82.5% ± 11.8% NS Mean sleep 95.7% ± 1.4% 95.6% ± 1.3% NS 4

arterial saturation Subjective Snoring, VAS Nadir sleep saturation 88.3% ± 3.5% 86.7% ± 5.5% NS 3

2 *Calculated as weight in kilograms divided by the square of the height in meters. †Unless otherwise indicated, data are mean ± SD. NS indicates not 1 significant. 0 Baseline Treatment Treatment Treatment 1 2 3 10 Figure 2. Subjective snoring (mean visual analog score [VAS]) after each 9 treatment. Error bars indicate 1 SD.

8 7.5 90 Baseline 7 Posttreatment 80 6 70 5 4.6 60 4

Subjective Snoring, VAS 50 3

40 2 P = .03

Proportion of Sleep, % 30 1

20 0 Baseline Posttreatment 10 Figure 1. Change in subjective snoring with treatment. Group means are indicated by the single dash; VAS indicates visual analog score. 0 40-50 50-60 >60 Range of Snoring Intensity, dB sity following treatment (baseline, 60.2 ± 3.9 dB; post- Figure 3. Mean proportion of sleep time spent at the different ranges of snoring intensity before and after completion of treatment. Error bars treatment, 64.9 ± 5.3 dB; P = .03). There was a slight indicate 1 SD. redistribution of snoring intensity, with a reduction in the proportion of sleep time spent snoring in the range of 50 to 60 dB (P = .03) and a marginal increase (not sig- cosa to the active electrode. The ulcers healed sponta- nificant) in snoring at 40 to 50 dB (Figure 3). neously by 3 to 5 weeks.

ADVERSE EFFECTS OF TREATMENT CEPHALOMETRY

There was minimal morbidity associated with the treat- The cephalometric parameters used are shown in ment. Visual analog scores for pain, swallowing, and Figure 5 and the data given in Table 2. There were speech are shown in Figure 4. There was a trend for trends toward a reduction in palatal width and length, more prolonged symptoms after the second treatment (to but these did not reach statistical significance. the distal third of the soft palate), but these differences were not significant. Patients used the combination drug CORRELATES WITH IMPROVEMENT paracetamol/codeine (500 mg/30 mg) for up to 4 days IN SUBJECTIVE SNORING after each treatment. Mucosal ulcers developed in 3 patients after the treat- The percentage change in subjective snoring intensity was ment to the distal third of the soft palate. In 1 of these significantly correlated with both total energy delivered patients, the lesion occurred following movement dur- (r = 0.29; P = .03) and time since first treatment (r = 0.25; ing treatment, which resulted in exposure of the mu- P = .05). However, each of these variables explains less

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Pain 4

A 10 PW PAS 8 PNS-P

4 C3 Swallowing B 2 C4 0

10 C5

8 Figure 5. Schematic representation of lateral cephalogram. SNA and SNB 6 indicate the angle between the sellar point to the nasion line and maxillary point (A) and mandibular point (B), respectively; PAS, posterior airspace, the Speech 4 minimum distance between the posterior pharyngeal wall and the soft palate; PW, maximum soft palate width; PNS-P, distance between the posterior 2 nasal spine and the tip of the uvula. 0 Treatment Treatment Treatment 1 2 3 Table 2. Cephalometric Data Before and After Treatment* Figure 4. Mean visual analog scores for pain, difficulty in swallowing, and changes in speech at 3 and 7 days after each treatment. Error bars indicate 1 SD. Measurement Baseline Posttreatment Significance SNA 80.2 ± 4.5 79.5 ± 4.8 NS SNB 77.7 ± 5.3 77.4 ± 5.4 NS than 10% of the total variation in improvement in sub- PAS 6.45 ± 2.41 4.80 ± 2.19 NS jective snoring. This measure did not correlate with base- PW 10.11 ± 1.97 9.34 ± 2.19 NS line demographic, polysomnographic, or cephalometric PNS-P 38.17 ± 2.39 37.00 ± 2.77 NS data. *Unless otherwise indicated, data are mean ± SD millimeters. SNA and SNB indicate the angle between the sellar point to nasion line and maxillary COMMENT point (A) and mandibular point (B), respectively; NS, not significant; PAS, posterior airspace, the minimum distance between the posterior pharyngeal wall and the soft palate; PW, maximum soft palate width; and PNS-P, Despite widespread interest in and promotion of RFTVR, distance between the posterior nasal spine and the tip of the uvula. there is a relative paucity of published information on its efficacy and adverse effects when used on the soft palate to treat snoring, and none on the effects of site of place- complication in our cohort. Our experience with this treatment of the lesions. Our study was aimed at addressing ment indicates that it is safe and well tolerated. these issues in a cohort of simple snorers. Most patients reported improvement in subjective Our study agrees with previous work6 that the pro- snoring following the treatment. However, only 8 pa- cedure seems to be associated with minimal morbidity tients (40%) described more than a 50% reduction in sub- and is suitable for outpatient administration. Only simple jective snoring. We were not able to identify clinical, poly- analgesia is required postoperatively, and subjects are able somnographic, or radiological characteristics useful in to return to work within hours of therapy. This is a dis- predicting a clinical response to treatment. The degree tinct advantage over other surgical modalities. Three pa- of improvement in objective snoring correlated only to tients developed mucosal ulceration, which was associ- the period since first treatment and total energy deliv- ated with minor discomfort and healed spontaneously ered to the soft palate. These parameters are interre- within 3 to 5 weeks. Each occurred following treatment lated because a standard energy was delivered for each to the distal third of the soft palate, as might be ex- treatment, and they explain less than 10% of the vari- pected because it is thinner, making placement of the le- ability in the improvement in subjective snoring. sion without breaching the mucosa more difficult. Post- Problems with appropriate selection of patients are procedural pain was also increased at this site. Previous not unique to this therapy. Patient selection has been ex- investigators6 have reported sloughing of the uvula as a tensively investigated with respect to conventional pala- complication of this treatment, which is likely to reflect tal surgery. Selection of patients with snoring generated coagulation of its arterial supply. We did not observe this only by palatal flutter should improve outcome from these

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©2000 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/26/2021 procedures. While wakeful fiberoptic nasopharyngos- We are satisfied that this therapy conforms to the copy seems to be of limited use,10 sleep nasendoscopy aphorism “first do no harm.” The procedure is rela- shows promise as a technique to locate snoring and has tively simple and well tolerated, and has minimal im- found noise generation at a site other than the soft pal- pact on the subjects’ capacity to work within hours post- ate in 30% of adult snorers.11 This may explain the vari- surgery, unlike conventional palatal surgery. The principle ability in clinical response to this therapy. Subjects with of treatment seems sound, and our evaluation suggests nonpalatal snoring would not be expected to improve with that it may prove to be a useful therapy. Placement of radiofrequency palatal reduction, and those with snor- the lesions toward the free edge of the soft palate seems ing arising from palatal flutter alone may improve more more effective but associated with more adverse effects than if snoring is generated from multiple sites. The use than placement near the hard palate. These findings jus- of sleep nasendoscopy to determine the site of snoring tify a randomized controlled trial, which is now re- has been shown to have predictive power in identifying quired to further evaluate the therapy. Number and place- success following uvulopalatopharyngoplasty.12 How- ment of lesions will be of considerable importance in the ever, it is a difficult procedure and not suitable for gen- design of such a study. eralized screening of patients being considered for palatal surgery. Accepted for publication November 17, 1999. There was a reduction in snoring overall following This study was supported by funds from Somnus Tech- treatment to the middle and distal thirds of the soft palate nologies, Sunnyvale, Calif. but not after the treatment to the proximal third. It seems Corresponding author: David R. Hillman, MD, FANZCA, that lesions directed toward the thinner, free edge of the Department of Pulmonary Physiology, Sir Charles Gairdner soft palate are more effective, but also seem to be associ- Hospital, Hospital Avenue, Nedlands, Western Australia ated with marginally more severe and prolonged adverse 6009, Australia (e-mail: [email protected]). effects. The treatment resulted in a trend toward a reduction in the length and width of the soft palate, which is con- REFERENCES sistent with our understanding of its mechanism. The for- mation of fibrous scar tissue would result in shrinkage of 1. Bearpark H, Elliott L, Grunstein R, et al. 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