UPPP IN RONCHOPATHY : OBJECTIVE EVALUATION
Service de Pneumologie, Laboratoire de Sommeil
If we do not have the assurance that snoring is a cardiovascular risk factor, it is a conjugal nuisance and the precursor of obstructive sleep apnea syndrome (OSAS). The definition of snoring is still clinical even though relatively simple equipment for respiratory sound recording and analysis of the signal is available and can give the caracteristics of snoring : number of events, mean intensity, frequency.
UPPP is a common surgery for snoring and OSAS.
It is however not a surgery without risks even if these are rare. The efficacy of UPPP in OSAS is now assessed by postoperative polysomnograms. Relating to snoring, assessment of the efficacy of UPPP has advanced in the literature in the past few years. It relied exclusively upon interviews with the bedpartner of the patients including the studies in 1994/1995; then the success rate was 75 to 100 %. For the past 3 years, objective quantification of snoring is realised with determination of snoring index, mean sound intensity and more recently frequency spectrum .
Relating to OSAS, Partinen (1996) demonstrates that UPPP has a poor success rate compared to nasal CPAP, which is nevertheless higher than the efficacy of conservative management (smoking cessation, alcohol avoidance, weight reduction). In opposition to He 's study (1988), Keenan did not find a significant difference in the long term survival of patients treated with UPPP and those treated with NCPAP.
Patients are satisfied (75 to 95% according to the literature) even though objective success rates vary with the criteria that is chosen to determine success and the timing of the postoperative recording.
In our study, 72,5% of 40 patients were satisfied while 31% only had a postoperative AHI < 10 after one year. With the same criteria, Fleury (1989) found 86,7% of patients satisfied whereas only 47 % had an objective success at 3 months. In Chabolle's study (1995), 82% of patients were improved regarding their sleepiness and 82% of bedpartners were satisfied with the evolution of the noise while 41% were real success at 9 months. These results are hardly comparable with other studies with different criteria : postoperative AHI< 50% preoperative AHI, or postoperative AHI < 20.
All the authors insist on the differences between subjective evaluation and objective results : Davis (1993) examined the patients 6 months after UPPP and found 85% satisfied whereas 57% had a postoperative AHI< 50% preoperative AHI ; Shao Jung Lu (1995) obtained 80% patients satisfied with decreased sleepiness whereas 57% had a postoperative AHI < 50% preoperative AHI after 1 year ; Larsson (1994) noted that 95% of responders and 87% of nonresponders were much improved and even free of symptoms at 6 and 21 months while 60% had a postoperative AHI < 20.
Relating to snoring, many studies evaluate effects of UPPP by interviewing bedpartners and using 3 to 5 choice scales. Levin (1994) and Janson (1994) demonstrated a clear initial improvment but a degradation of the results at the subsequent exams and even a return to the preoperative discomfort for respectively 24,6% and 28,5% at 1 and 2 years. Friberg (1995) reexamined 5 years after UPPP 56 non apneics snorers (NAS) : 66,1% reported they were less or no longer sleepy and 60,7% pointed out that the noise was much less loud and more high pitched.
Few studies objectively assess post UPPP snoring : Miljeteig (1994) gave the results of 69 patients (31 OSAS and 38 NAS), Walker (1996) presents the results of 27 patients with an evolution of the frequency spectrum, we report the results of 40 patients ( 29 OSAS and 11 NAS).
Table 1 shows these results with a comparison between subjective evaluation and objective measures of snoring .
Snoring recordings allow us to compare our results and Miljeteig's . For 51.7 % of our satisfied patients we did not notice any change in the SI, the AHI, the mean intensity of sound. Miljeteig did not find any significant difference in SI, dB mean or dB max whereas 60.9% of his patients are satisfied In these 2 studies, satisfied patients with no objective change reported an improvment in sleep quality after surgery (respectively 80% in our study and 79% in Miljeteig's); Guilleminault (1983) and Fleury (1989) reported an increase of slow wave sleep and a diminution of microarousals after UPPP in OSAS. Decreased sleepiness is often reported by patients. We noted a certain agreement between the satisfaction of the patients and the diminution of a sleepiness score: in our 29/40 satisfied patients, it varied from 6,6+/-3,2 to 2,2+/-2,8 and 23 patients said they had a better sleep ; in our 11 unsatisfied patients, it varied from 5,1+/-2,5 to 3,6+/-2,9 and only 1 said he had a better sleep. The satisfaction of the patients may then be explained by the improvment of the sleep quality and the decrease of the sleepiness.
In addition the noise changes. Walker (1996) demonstrated that the post operative mean frequency is higher than in preoperative recordings : 178 Hz versus 106 Hz. In our study, the mean frequency of snoring in postoperative was 144 Hz for the satisfied bedpartners versus 99 Hz for the unsatisfied bedpartners. Obtaining a sound more high pitched may explain the satisfaction of the patients whereas neither SI, nor intensity diminished in post UPPP.
Whereas 72,5% of patients are satisfied with the UPPP, 90% retain a SI > 100 and 69% of OSAS still have an AHI > 10 in our study. This leads us to believe that the choice of re-examination periods and the choice of efficiency criteria have to be discussed. The lack of correlation between the satisfaction of the patient and the bed partner and the objective test results can be explained by the fact that the quality of sleep is improved, the daytime sleepiness diminished and the higher pitch of the snore.But is the aim of UPPP only to satisfy the patient and his/her bedpartner? It seems that one can not rely on a simple interrogation in order to determine the efficacy of the UPPP. Rather, it is necessary to quantify the snoring both before and after the surgery - especially if one considers snoring something more than a social nuisance.