Surgery for sleep apnea. Long-term results

Abstract

Background

Upper airway surgery is an effective treatment for OSA, improving both subjective and objective parameters that define the condition. However, the long-term stability of this improvement remains unclear.

Methods

An ambispective observational study was conducted using data from the Dr. Peset Hospital (Valencia, Spain) on patients who underwent palatal surgery using modern pharyngoplasty techniques between 2015 and 2023. A total of 83 patients were included, with follow-ups conducted at a mean of 7, 35, 51, 68, and 85 months post-surgery. Objective and subjective parameters were analyzed.

Results

Significant improvements were observed in AHI (from 38.82 ± 21.26 to 16.30 ± 16.60), ODI (from 40.71 ± 21.18 to 16.93 ± 18.02), T90 (from 16,31 ± 22.58 to 6.68 ± 10.50), and minimum oxygen saturation (from 76.14 ± 13.54 to 84.52 ± 7.74), as well as in subjective measures, following surgery. At the third follow-up, at a mean of approximately 4.2 years, the AHI was 15.30 ± 11.00, the ODI was 14.30 ± 12.02, the T90 was 8.51 ± 16.99, and the minimum oxygen saturation was 84.66 ± 6.84. These improvements persisted over time, although there is slight worsening in some cases.

Conclusions

Sleep surgery is effective in reducing OSA-related parameters and improving quality of life. Long-term follow-up indicates that these benefits are largely maintained, with minor variations over time. These findings support surgery as stable treatment for OSA, highlighting the importance of individualized surgical approaches and postoperative monitoring.

Resumen

Antecedentes

La cirugía de la vía aérea superior es un tratamiento eficaz para la AOS, con mejoría de parámetros subjetivos y objetivos que definen la enfermedad. Sin embargo, la estabilidad de esta mejoría a largo plazo no está clara.

Metodología

Se realizó un estudio observacional ambispectivo con datos del Hospital Dr. Peset (Valencia, España) en pacientes sometidos a cirugía palatal mediante técnicas modernas de faringoplastia entre 2015 y 2023. Se incluyeron 83 pacientes, con seguimientos realizados a una media de 7, 35, 51, 68 y 85 meses tras la cirugía. Se analizaron parámetros objetivos y subjetivos.

Resultados

Se observaron mejorías significativas en el IAH (de 38,82 ± 21,26 a 16,30 ± 16,60), el ODI (de 40,71 ± 21,18 a 16,93 ± 18,02), el T90 (de 16,31 ± 22,58 a 6,68 ± 10,50) y la saturación mínima de oxígeno (de 76,14 ± 13,54 a 84,52 ± 7,74), así como en las medidas subjetivas, tras la cirugía. En el tercer control, a una media de aproximadamente 4,2 años, el IAH fue 15,30 ± 11,00, el ODI 14,30 ± 12,02, el T90 8,51 ± 16,99 y la saturación mínima 84,66 ± 6,84. Estas mejorías se mantuvieron en el tiempo, aunque con un ligero empeoramiento en algunos casos.

Conclusiones

La cirugía del sueño es eficaz para reducir los parámetros relacionados con la AOS y mejorar la calidad de vida. El seguimiento a largo plazo indica que estos beneficios se mantienen en gran medida, con variaciones menores a lo largo del tiempo. Estos hallazgos respaldan la cirugía como un tratamiento estable para la AOS y subrayan la importancia de un enfoque quirúrgico individualizado y del seguimiento postoperatorio.

Introduction

Obstructive sleep apnea (OSA) is a chronic disorder characterized by the recurrent collapse of the upper airway during sleep, leading to intermittent hypoxemia, sleep fragmentation, and a significant impact on both quality of life and morbimortality.¹ Although continuous positive airway pressure (CPAP) is the first-line treatment for OSA, many patients are unable to tolerate this therapy. This limitation has driven the development of other therapeutic approaches, both surgical and non-surgical, which ideally should be tailored to the individual characteristics of each patient.²

Pharyngoplasty, in its various forms, aims to remodel and stabilize the upper airway to prevent pharyngeal collapse.

Over the years, upper palate surgery has undergone significant evolution. The uvulopalatopharyngoplasty (UPPP), performed by Quesada and Perelló³ popularized by Fujita,⁴ has long been the main surgical approach for patients with obstructive sleep apnea (OSA). However, as a resective technique with a spatial (rather than functional) focus, it is not without complications,⁵ including a tendency toward inadequate restenosis.

In 2003, Cahali introduced a novel technique, lateral pharyngoplasty (LP), which shifted the approach from a spatial to a functional perspective, transitioning from excision of the mucosa to the weakening of the constrictor muscle. In 2004, Friedman introduced Z-pharyngoplasty (ZP) as a surgical alternative for tonsillectomized patients with Friedman stage III and IV.⁶

Subsequently, in 2007, Pang and Woodson described expansion pharyngoplasty (EP), which involves mobilization of the palatopharyngeal.⁷ In 2019, Li and Lee introduced relocation pharyngoplasty, which aims to anteriorly reposition the soft palate.⁸

In 2012, Mantovani introduced the use of barbed sutures, anchoring the soft tissues of the pharynx to more rigid structures such as the pterygopalatine raphe (the "coaxial tubes theory") to maintain airway patency.⁹ In 2015, Vicini, inspired by Li and Lee’s technique, further developed barbed repositioning pharyngoplasty (BRP), using barbed sutures in a submucosal plane to weaken the palatopharyngeal muscle and reposition it more anteriorly and laterally.^10,11 In 2018, Mantovani described the Alianza technique, which combines two previously introduced techniques—the Roman Blinds Technique and Modular Barbed Snore Surgery. This approach is a conservative, non-resective technique.¹²

Modern pharyngoplasty techniques have evolved from traditional resective approaches—centered on volumetric reduction of the soft palate and uvula—to anatomically and functionally oriented procedures that prioritize tissue preservation. These contemporary methods aim not only to enlarge the airway but also to prevent dynamic collapse by providing structural support and repositioning soft tissues without resection. Techniques such as expansion pharyngoplasty, anterior palatoplasty, Friedman’s technique, Pang’s technique, and modified reposition pharyngoplasty with barbed sutures exemplify this functional, non-resective philosophy, in contrast to classical pharyngoplasties, which rely on tissue removal and lack a functional preservation approach.

These interventions have demonstrated efficacy in improving sleep parameters and reducing the severity of OSA in the short term. Long-term research is lacking and it is suggested that while initial improvements are often sustained over the first few years, patients experience a progressive decline in clinical benefits over time. However, the long term stability of these outcomes is a growing area of interest, as factors such as aging, weight gain, and disease progression may contribute to symptom recurrence.^13,14 Recent studies have begun to assess the stability of surgical outcomes in patients undergoing pharyngoplasties. The deterioration phenomenon underscores the importance of considering individual factors and specific surgical techniques.¹⁵

The objective is to evaluate the long-term results of sleep parameters in OSA patients with CPAP intolerance who underwent pharyngoplasty.

Materials and methods

Study design

This is an ambispective observational study. Data were collected from Dr. Peset Hospital (Valencia, Spain) involving patients with OSA who underwent palatal surgery using modern pharyngoplasty techniques between 2015 and 2023. Two databases were utilized for this purpose: a retrospective database covering patients recruited from 2015 to October 2019 and a prospective database covering patients recruited from November 2019 to January 2023. Part of the patient sample on which this study is based has been used previously in other research articles.^11,15 Patients who had undergone resective and non-conservative pharyngoplasty techniques, such as uvulopalatopharyngoplasty (UPPP), were excluded from the study. The Ethics Committee of Dr. Peset Hospital approved the ambispective study on the long-term stability of sleep surgery (CEIm: 97/24) and the creation of both databases. All patients provided informed consent prior to undergoing surgery.

Inclusion criteria

• 1

  Patients with moderate-severe OSA treated with modern pharyngoplasties.

• 2

  Age between 18 and 65 years.

• 3

  Availability of at least two sleep studies: one prior to the surgical intervention and at least one post-intervention.

Exclusion criteria

• 1

  Patients who did not undergo palatal surgery or were treated with classic pharyngoplasties.

• 2

  Absence of sleep studies performed after surgery or studies conducted while using CPAP, mandibular advancement device, or positional therapy.

• 3

  Patients who underwent surgery with an apnea- hypopnea index (AHI) lower than 15

• 4

  Significant craniofacial anomalies.

• 5

  Severe psychiatric, cardiopulmonary, or neurological disease.

• 6

  Pregnancy.

The following clinical data were collected: age, gender, body mass index (BMI), physical examination findings such as neck circumference, palatine tonsil grade, Woodson retrolingual space classification,¹⁶ Mallampati and modified Mallampati score,¹⁷ Friedman stage and lingual tonsil grade.¹⁸

The subjective parameters evaluated during post-surgical follow-up included the Epworth Sleepiness Scale (ESS) and the Quality of Life (QoL) using Visual Analog Scale (VAS) for well-being which is a subjective measurement tool represented by a continuous line. At one end of the scale (0), the patient indicates that their well-being is at its worst, and at the other end (10), the patient indicates that their well-being is at its best. This scale is used to quantitatively assess the patient's perception of well-being.¹⁹

All patients underwent a sleep study and completed clinical questionnaires both prior to and after the surgery (>6 months post-intervention).

Regarding the sleep study, various parameters were collected: the apnea-hypopnea index (AHI), the oxygen desaturation index (ODI), the minimum oxygen saturation during sleep (MinSat), and the percentage of total sleep time with blood oxygen saturation below 90% (T90). Mild obstructive sleep apnea (OSA) has been described as an AHI greater than 5 but not exceeding 15 events per hour. Moderate OSA corresponds to an AHI between 15 and 30 events per hour. Severe OSA is defined as an AHI greater than 30 events per hour.

The pharyngoplasties evaluated in this study could include concomitant tonsillectomy or nasal surgery, in which case they were classified as single-level surgeries, or they could include lingual or epiglottic surgery, in which case they were classified as multi- level surgeries. The surgical indication was based on information gathered from the patient’s medical history and physical examination prior to surgery, as well as findings from drug induced sleep endoscopy (DISE) and parameters from the sleep study.

Post-surgical follow-up was conducted through a new sleep study and a patient interview, during which the ESS and quality-of-life questionnaires were completed. Follow-up evaluations were scheduled at 6, 18 and 30 months after the intervention, although variability in follow-up times was observed in some cases. Despite this, the protocol remained consistent. Some patients underwent a third, fourth, and even fifth post-surgical evaluation. These follow-ups exceed the 34-month threshold used in other studies to define long-term follow-up.²⁰

A comparative analysis was performed between preoperative and postoperative variables.

Main outcome: To evaluate the stability of surgical outcomes in OSA patients who underwent palatal surgery, measured through objective and subjective parameters.

Secondary objective: To assess whether this stability is maintained across different types of palatal surgery and multi-level surgeries.

Statistical analysis was performed with Stata14 (Stata-Corp 4905, Lakeway Drive College Station, Texas 77,845, USA). Continuous variables are described as means with standard deviation. Qualitative variables are described as proportions. After verifying normality, the t test was used to compare continuous variables, and Chi-square or Fisher’s test for categorical variables. For continuous variables that did not meet the normal distribution, the Wilcoxon signed-rank test was performed. The relative improvement of AHI has been calculated. This metric quantifies the percentage change in the apnea-hypopnea index after the intervention, relative to the baseline value, and it is calculated as follows: first, subtracting the post-treatment AHI from the pre-treatment AHI and then, this difference is divided by the pre-treatment AHI to determine the proportional change relative to the initial value. Finally, the result is multiplied by 100 to express the improvement as a percentage. The relative improvement of AHI follows this formula: [(pre AHI–post AHI)/pre AHI] × 100. A higher positive value indicates a greater reduction in AHI, reflecting an improvement in sleep apnea severity.

For all cases, the level of significance was set at <0.05. To study the evolution of the different variables in regard to time, regression equations were carried out and represented through scatter diagrams.

Results

A total of 83 patients completed the first post-surgical follow-up at an average of 219 days (approximately 7 months) after surgery. The second follow-up, completed by 41 patients, occurred around 1,056 days post-surgery (approximately 35 months). Twenty- four patients attended the third follow-up at an average of 1,546 days (approximately 51 months), 13 patients completed the fourth follow-up at 21975 days (around 68 months), and 9 patients underwent the fifth and final follow-up approximately 2553 days (7 years or 85 months) after surgery.

Patients were classified according to their pre-surgical AHI. A total of 38 patients (45.78%) were classified with moderate OSA, and 45 patients (54.22%) as severe OSA.

Table 1 summarizes the baseline values and the subsequent follow-ups for both subjective and objective variables. It also includes the total number of patients in each follow-up as well as the average number of days elapsed between the surgery and each follow-up. For the AHI, statistically significant differences were observed between baseline and postoperative values across all follow-ups.

Table 1.

General values prior to surgery and during successive follow-ups. The table displays the average number of days elapsed since surgery for each follow-up.

	V0 (N:83)	V1 (N:83)	V2 (N:41)	V3 (N:24)	V4 (N:13)	V5 (N:9)
AHI	38.82 (21.26)	16.30 (16.6)*	12.48 (10.02)*	15.30 (11.00)*	22.76 (17.04)*	13.85 (10.25)*
ODI	40.71 (21.18)	16.93 (18.02)*	13.81 (11.67)*	14.30 (12.02)*	21.20 (16.80)	16.32 (12.19)
T90	16.31 (22.58)	6.68 (10.50)*	2.86 (4.32)*	8.51 (16.99)	2.2 (2.27)*	4.03 (5.68)
MinSat	76.14 (13.54)	84.52 (7.74)*	84.52 (6.84)*	84.66 (6.84)*	82.16 (5.74)	80.32 (10.21)
ESS	8.50 (4.90)	5.47 (4.41)*	4.56 (3.26)*	5.28 (4.25) *	4.27 (1.61) *	4.00 (2.60)
QoL	4.14 (2.00)	7.16 (2.17)*	6.68 (2.05)*	7.09 (2.15) *	6.92 (2.55)	7.53 (2.24)
BMI	27.88 (3.78)	27.86 (3.86)	27.26 (5.08)	27.72 (3.93)	27.07 (3.77)*	26.90 (2.57)
Days after surgery	Pre-surgical value	219 (135)	1056 (764)	1546 (669)	1975 (674)	2553 (709)

Pre-surgical values and values from successive follow-up visits are presented. The last row shows the average time of these visits post-surgery. It has been studied whether there are differences between follow-up subgroups and baseline values across the different variables. The * symbol indicates p < 0.05. Values in parentheses represent the standard deviation.

Regarding other variables, no statistically significant differences were found in BMI during the first, second, third, and fifth follow-ups. This suggests that changes in AHI values are not attributable to changes in BMI. However, significant differences in BMI were observed during the fourth follow-up, likely due to the small sample size in that subgroup.

For the remaining variables, a statistically significant reduction in both subjective and objective parameters was observed during the first postoperative visit. These differences compared to baseline values remained statistically significant during the second visit, and continued to be stable throughout the rest of the follow-up period, except for a few exceptions.

In general, the analysis indicates that the improvement following surgery is remarkable and sustained over time, with slight variations.

Despite the fact that there is a tendency to worsen such positive results, the parameters remain far from baseline, even in the most distant follow-ups, conducted at an average of 68 and 85 months post-surgery.

Table 2 presents the mean AHI throughout the follow-up, classifying the sample into patients who underwent multi-level and single-level surgery. In the single-level surgery group, statistically significant differences were observed at all follow-up time points. The multilevel surgery group showed statistically significant differences only at the first and second follow-ups.

Table 2.

Pre-surgical and post-surgical mean AHI values, separating patients according to the type of surgery: single-level or multi-level.

	Pre	V1	V2	V3	V4	V5
Multilevel surgery	40.55 (21.94) N:17	17.57 (15.38) N:17*	14.57 (10.03) N:9*	21.05 (15. 11) N:6	33.5 (25.44) N:4	5.9 (4.66) N:2
Single level surgery	38.37 (21.23) N:66	15.97 (16.70) N:66*	11.90 (10.09) N:32*	13.39 (8.99) N:18*	17.98 (10.47) N:9*	16.12 (10. 46) N:7

Pre-surgical values and those from successive follow-up visits are shown, classifying patients according to the type of surgery: multi-level or single-level. The * symbol indicates p < 0.05. Values in parentheses represent the standard deviation.

Table 3 shows the mean AHI in the total population and in subgroups of patients classified according to the surgical technique throughout the follow-up: BRP, EP + AP, ZP, EP, LP, AP, and Alianza. A clear reduction in the mean AHI is observed after surgery, with variable stability of the results. Pharyngoplasty with barbed suture stands out as the subgroup with the highest number of patients, showing statistically significant differences compared to baseline, in all the follow-up. It is important to note that dividing the total sample into subgroups reduced the size of each study group, which may have led to more extreme values.

Table 3.

The pre-surgical mean AHI values and the mean of postoperative AHI values from successive follow-up visits are shown according to the type of palatal surgery.

	Pre-surgical AHI value	V1	V2	V3	V4	V5
General AHI	38.82 (21.26) N:83	16.30 (16.6) N:83*	12.48 (10.02) N:41 *	15.30 (11.00) N:24*	22.76 (17.04) N:13*	13.85 (10.25) N:9*
BRP	43.66 (22.70) N:48	15.72 (17.88) N.48*	10.39 (7.98) N:22*	15.42 (11.53) N:15*	25.67 (16.93) N:11*	17.35 (10.24) N:6
EP + AP	23 N:1	3.43 N:1	10 N:1	10.7 N:1
ZP	22.72 (4.16) N:4	14.20 (8.92) N:4	21.4 (14.9) N:3		4.4 (0) N:1
EP	26.9 (13.52) N:14	15.02 (18.04) N:14*	7.93 (6.12) N:7*	10.08 (5.83) N:4	9.1 (0) N:1	9 (8.34) N: 2
LP	34.42 (16. 99) N:7	15.09 (14.72) N:7	18.7 (13.99) N:7	15.71 (9.42) N:3		2.6 (0) N:1
AP	36.8 (26.49) N:3	15.13 (17.21) N:3
Alianza	47.53 (21.33) N:6	29:46 (22.19) N:6	20.03 (13. 68) N:3	37.9 (0) N:1

The * symbol indicates p < 0.05. Values in parentheses represent the standard deviation. BRP: barbed reposition pharyngoplasty, EP: expansion pharyngoplasty, ZP: Z-palatoplasty, LP: lateral Pharyngoplasty, AP: anterior pharyngoplasty.

Figs. 1 and 2 show a graphical representation of each patient's AHI value over the successive follow-up periods. Fig. 1 includes all patients, while Fig. 2 shows only the patients who have reached the fifth follow-up (a total of 9).

Figure 1.

Representation of AHI progression over time, all the patients included.

Figure 2.

Representation of AHI progression over time in the 9 patients who completed the fifth follow-up.

Table 4 shows the success rate according to Sher and the relative improvement in AHI for the total number of patients, as well as classified by the type of surgery across successive follow-ups.

Table 4.

The surgical success rate according to Sher and the relative improvement in AHI is shown for the different follow-up visit after surgery, classified by the different types of surgery.

Type of Surgery	Success V1	AHI RI V1	Success V2	AHI RI V2	Success V3	AHI RI V3	Success V4	AHI RI V4	Success V5	AHI RI V5
BRP	75%	60.86% (32.24)	81.82%	71.27% (29.14)	60%	50.77% (49.92)	27.7%	33.24% (44.44)	66.67%	36.27% (57.65)
EP + AP	100%	85.08%	100%	56.52%	100%	53.47%
ZP	75%	40.65% (32.23)	33.33%	4.70% (61.63)			100%	75.69%
EP	85.71%	45.13% (53.61)	85.71%	63.28% (36.28)	50%	54.17% (25.30)	100%	51.07%	50%	56.35% (38.14)
LP	71.43%	46.77% (54.92)	20%	25.55% (58.14)	33.33%	37.73% (51.70)			100%	96.32%
AP	66.67%	65.81% (17.07)
Alianza	50%	38.74% (30.67)	66.67%	54.63% (7.96)	0%	15.21%
Global	74.70%	57.89% (40.27)	70.73%	57.89% (40.27)	54.17%	48.29% (43.67)	38.56%	37.87% (42.41)	66.67%	47.41% (51.68)

Success rate according to Sher’s criteria for each patient subgroup and the relative improvement of the AHI are shown. RI (Relative improvement). Values in parentheses represent the standard deviation. The number of patients in each subgroup is already shown in Table 3. BRP: Barbed reposition Pharyngoplasty, ZP: z-palatoplasty, EP: expansion pharyngoplasty, LP: lateral pharyngoplasty, AP: anterior palatoplasty.

Table 5 shows pre-surgical values for patients grouped by follow-up visits, indicating minimal differences between patients with fewer follow-ups and those with extended follow-up durations. Minimal differences are observed in the pre-surgical values among the different groups according to the number of follow-ups achieved. A statistical analysis has been conducted comparing the overall pre-surgical values of the different variables with the pre-surgical values of the group with the most follow-ups. Statistically significant differences are only found in the mean saturation variables and BMI.

Table 5.

The pre-surgical sleep parameters for all patient subgroups are shown according to the number of follow-ups they have completed.

	V1(N:83)	V2(N:41)	V3(N:24)	V4(N:13)	V5(N:9)
AHI	38.82 (21.26)	37.56 (19.40)	39.61 (21.79)	39.99 (24.48)	36.25 (21.10)
ODI	40.71 (21.18)	39.20 (20.75)	37.3 (22.03)	38.1 (21.24)	33.93 (17.66)
T90	16.31 (22.58)	10.74 (14.92)	9.84 (17.48)	5.47 (2.32)	4.95 (3.37)
MinSat	76.14 (13.54)	77.53 (10.42)	78.41 (11.23)	81.32 (8.18)	83.66 (9.78) *
ESS	8.50 (4.90)	8.05 (4.5)	7.83 (4.67)	9.53 (4.89)	7.55 (4.74)
QoL	4.14 (2.00)	4.56 (2.17)	4.33 (2.05)	3.60 (2.28)	3.95 (2.94)
BMI	27.88 (3.88)	27.22 (3.79)	27.02 (3.71)	25.60 (3.17)*	25.18 (3.53)*

It has been studied whether there are statistically significant differences between the pre-surgical values of the group that reached the final follow-up and the overall pre- surgical values. Values in parentheses represent the standard deviation. The * symbol indicates p < 0.05.

Discussion

In this real-world clinical practice study on the long-term outcomes of patients with obstructive sleep apnea (OSA) who underwent surgery, we observed that results tend to remain stable over time, with only a slight deterioration in some cases.

The results of this study reaffirm the stability of outcomes in sleep apnea surgery, as previously supported by Martínez Ruiz de Apodaca et al.¹⁵ In the referred study, the superiority of modern techniques over classical palatal surgery techniques was observed in terms of long-term outcome stability. This is the reason why classical pharyngoplasty techniques have been excluded from the present study. When comparing the different types of surgery, some instability in the AHI value over time is observed, particularly in Alianza-type pharyngoplasty. The reason for this poorer outcome may be that this technique is typically performed in patients with complete concentric collapse of the soft palate, a condition generally associated with less favorable surgical results.²¹ When examining the overall AHI results in Table 1, these differences over time appear more subtle, aligning more closely with the results reported.¹⁵

When comparing the results between patients who underwent multi-level and single- level surgery, a high degree of stability is observed in the outcomes of the latter group. These results are similar to those previously reported.¹⁵ This finding is reasonable for two reasons. First, patients undergoing multilevel surgery tend to exhibit more complex collapse patterns, which makes them more difficult to treat due to the greater number of factors that may contribute to unfavorable outcomes. Second, dividing the sample into subgroups leads to a very small number of patients in the multilevel surgery group at later follow-up points. Additionally, this ambispective study draws upon the retrospective cohort of patients with obstructive sleep apnea (OSA) from Dr. Peset Hospital, the same source used in the previously cited articles.^11,15 The retrospective cohort comprises patients from 2002 to 2019; in the present analysis, only patients from this cohort treated from 2015 onward were included. In one of the referenced studies, patients were selected from 2006 to 2019¹¹, whereas in the other, from 2002 to 2019.¹⁵ Moreover, one of those articles excluded patients with mild OSA¹¹, whereas the other did not. ¹⁵ The retrospective cohort continues to accumulate follow-up visits even though no new patients are being added. Consequently, some patients appear in all three studies, with longer follow-up in the more recent ones, consistent with the primary objective of the present study. It is important to emphasize that this work includes both newly enrolled patients from the prospective cohort and newly collected data from retrospective patients.

A statistically significant reduction in the AHI parameter was observed, even at 80 months of follow-up. Additionally, it was noted that, in the long term, some variables worsen but still maintaining a benefit from surgery, as reported in other studies.²⁰ Differences in outcomes were observed when dividing the sample according to the type of surgery. This could be attributed to the small sample size of these subgroups.

Although the stability of the relative improvement in AHI is valuable, more robust indicators include the success rate according to Sher, which remains stable throughout the follow-up period with only slight decreases.

It is well known that age is an aggravating factor in obstructive sleep apnea.²¹ The sleep architecture changes with age, as does the neuromuscular/central response. Additionally, the proportion of fat mass to lean mass varies, with an increase in the former. It is accompanied by the loss of muscle tone and the increase in flaccidity of soft tissues.²² The consequences of the passage of time in OSA patients will not differentiate between operated and non-operated patients. However, some authors suggest the possibility of a greater effect of time in operated patients, arguing that changes in the surgical scar itself and the loss of the initial tensile effect of the sutures may cause a more pronounced worsening over time in these patients.²³

It is of great importance to determine the stability of sleep surgery outcomes in OSA patients. If a patient were to inadvertently return to their original condition or experience a worsening of their pathology, they would remain at risk due to the disease and its associated comorbidities, while holding a false perception of health. Therefore, it is crucial to conduct follow-ups on OSA surgery patients not only to confirm their initial improvement after surgery but also to ensure that this improvement is maintained over time. If this is not the case, alternative therapeutic approaches could be considered for the patient. This article contributes to a better understanding of the long-term behavior of surgically treated OSA patients.

The main limitation of this study is the loss of some patients during follow-up. The primary reason for this loss is that certain patients do not attend their follow-up appointments. Some patients were lost during the Covid pandemic time when the medical activity was cancelled. Another reason is that some patients for whom the surgery was unsuccessful remain on CPAP therapy, with their follow-up conducted by pulmonology specialists. In these cases, control polygraphy studies are performed while using CPAP, rendering them unsuitable for this study.

Another weakness of the study is the presence of missing data in some secondary variables. This occurs in some cases because patients did not fully complete the questionnaires, or because the follow-up interview could not be completed, even though the sleep study was.

Additionally, a lack of uniformity in the type of surgeries performed—seven in total—is another limitation. Some patients also underwent lingual and epiglottic surgeries (multi- level surgeries), which further contributes to the heterogeneity of the study population. Nevertheless, this reflects daily clinical practice, making the results applicable to any setting.

This study has several strengths that enhance its contribution to the field of sleep apnea surgery. One notable strength is the inclusion of long-term follow-up periods, extending up to 85 months (approximately 7 years), which provide valuable insights into the durability of surgical outcomes in OSA patients. The comprehensive data collection, encompassing both subjective parameters such as the Epworth sleepiness scale and quality of life, and objective measures including the apnea-hypopnea index, oxygen desaturation index, and minimum oxygen saturation, offers a holistic view of the surgical impact. The study also evaluates outcomes across a broad range of surgical techniques, including multi-level and single-level surgeries, and specifically analyzes seven distinct types of palatal procedures, which broadens its scope and clinical applicability. Additionally, the use of standardized metrics, such as Sher's classification, ensures reliable and objective assessment of surgical success. Another key strength is the identification of slight worsening over time, while confirming that significant improvements persist, even at later follow-ups. These findings contribute to a better understanding of the long-term stability of surgical benefits and reaffirm previous conclusions reported in the literature, such as those by Martínez Ruiz de Apodaca et al.¹⁵ and others, such as those from the Karolinska University Hospital.²⁴ Furthermore, the study highlights the variability in outcomes based on surgical type and individual patient characteristics, emphasizing the importance of personalized approaches in the management of OSA. The long-term follow-up of patients allows for objectively assessing the persistence of improvement in patients with sleep apnea, making it possible to detect those for whom surgery has not been successful and thus consider alternative therapies if necessary.

Conclusions

Palatal surgery in patients with obstructive sleep apnea proves to be a successful approach for reducing the parameters associated with this condition. The results indicate that, following the intervention, there is a significant reduction in these parameters and improving sleep quality.

Furthermore, the analysis of stability over time reveals that the benefits of surgery are maintained. Although slight variations are observed with values tending to worsen little by little, these variations do not significantly compromise the overall efficacy of the intervention. These findings support palatal and multilevel surgery as an effective and relatively stable tool over time for managing OSA, highlighting the importance of long- term follow-up to monitor potential changes and optimize clinical outcomes.