The Pillar Implant procedure is an obstructive sleep apnea (OSA) treatment option that has been around for several years but has more recently received a significant amount of publicity. The procedure is a form of oropharyngeal surgery involving the placement of three polyester implants in the soft palate under local anesthesia during a single-stage office procedure. The implants are placed into tissue that spans both the soft and hard palate, thus bridging the two and providing increased support of the soft palate, much like battens in a sail prevent the sail from luffing when the wind is low. The procedure seems to be logical in the sense that it is minimally invasive in comparison to a uvulopalatopharyngoplasty (UPPP) or other oropharyngeal surgery utilized in the treatment of OSA, but what is the true treatment efficacy of the Pillar Implant procedure?

EFFICACY OF “TRADITIONAL” MODALITIES

Before looking at the data for the Pillar Implant procedure specifically, it is helpful to review the data for more commonly utilized treatment modalities for OSA. Continuous positive airway pressure (CPAP) therapy is the gold standard and the most efficacious, commonly utilized treatment in patients with OSA. Other commonly utilized treatment modalities include mandibular advancement devices and oropharyngeal surgery. Although there have been many individual studies that have assessed the efficacy of each treatment option, one way to get an overall picture of relative treatment efficacies is through performing a meta-analysis by combining and analyzing the data of many research studies together. There are some inherent weaknesses in performing such a review; however, it also provides one with the ability to see a bird’s-eye view of the data. One such comprehensive review of 89 publications compared these treatment modalities performed between 1982 and 2006 and involving a total of 3,027 patients with OSA; it demonstrated that CPAP therapy effectively reduces the initial apnea-hypopnea index (AHI) by 75%, mandibular advancement devices by 42%, and UPPP by 30%.1 Thus, although CPAP therapy is not easily tolerated by all patients, short of a tracheostomy, it is the most successful treatment option that we have.

Until 2006, very little data regarding the Pillar Implant procedure was available. One prospective, nonrandomized study of 53 patients with OSA conducted at five clinical sites demonstrated a small decrease in the AHI from 25.0 +/- 13.9 to 22.0 +/- 14.8 events/hour (P = 0.05) following the Pillar Implant procedure.2 The largest and thus possibly the most informative study looking at the efficacy of the palatal Pillar Implant procedure involved 62 nonobese adults with a history of snoring, daytime sleepiness, and mild/moderate OSA who were randomized to receive palatal implants (n = 31) or placebo procedure (n = 31). Although the authors concluded that the treatment group was significantly improved compared with the placebo group, in actuality improvement in the AHI was negligible at 0.9 +/- 4.3.3 These studies do not provide conclusive evidence that the Pillar Implant procedure has a significant role in the treatment of sleep-disordered breathing.

COMPARING MODALITIES

The discrepancy in treatment modality efficacy data begs the question as to why CPAP is so much more effective than the other modalities, and why can’t something as simple as the Pillar Implant procedure work any better than it does? Besides CPAP therapy, other treatment options include weight loss, oropharyngeal surgery, treatment of nasal congestion, and the use of mandibular advancement devices.4 The rationale regarding the use of these devices is that by advancing the jaw forward, the base of the tongue may also be advanced forward away from the posterior oropharyngeal wall. These devices may also increase the volume of the effective oropharyngeal airway at the level of the velopharynx, or the more superior area of the posterior oropharynx that is more commonly occluded by the soft palate in patients with OSA.

In most patients, it is the vibration of the soft palate against the velopharynx that leads to snoring and hypopneas, while complete obstruction can lead to frank apneic events. The rationale behind oropharyngeal surgery is that the structures involved in the obstruction itself are trimmed or altered in morphology so that airway obstruction is minimized and the airway remains patent.

The rationale behind the Pillar Implant procedure seems to make sense. In many cases, the soft palate is the structure that reverberates against the posterior oropharyngeal wall during snoring, and often obstructs the airway during sleep obstructive apneic events. So why would a procedure that strengthens the soft palate not effectively treat sleep-disordered breathing? Similar logic in regard to subtraction of the palatal tissue brought the advent of the UPPP, or the most commonly performed type of oropharyngeal surgery for the treatment of OSA.

Initially, the excitement for the procedure must have been great. After all, if the soft palate is the principal structure involved in the obstruction of the airway, then it stands to reason that trimming it will mitigate the magnitude of sleep-disordered breathing. Unfortunately, the data supporting the true efficacy of the procedure has been less than that initially hoped for. Although there may be selective patient groups who make very good candidates for the procedure, the procedure for OSA patients as a whole is not as effective as either CPAP therapy or even as effective as mandibular advancement devices.

One possible explanation for such a divergence in treatment efficacies arises from the simple fact that CPAP therapy opens the entire airway. An oversimplified anthropomorphic explanation is that CPAP therapy “doesn’t care” where the obstruction is, it simply opens the entire airway. A mandibular advancement device may advance the base of the tongue in an anterior direction, and it may also tug on the palatoglossus muscles, pulling the soft palate open to some degree, but this may not completely and effectively alleviate the obstruction, based on a number of anatomical factors. For example, the exact dimensions of the mandible, the volume and morphology of the tongue, the length and tensile strength of the palatoglossus muscles, the baseline diameter of the airway, and the degree of fat deposition along the posterior and lateral aspects of the posterior airway may all vary from individual to individual. Even if the mandibular advancement device successfully opens the airway after all of these factors are considered, simply limiting nasal airflow with nasal congestion or obstruction can then significantly limit the efficacy of such a device.

A tunnel can be wide open at one point, but all it takes is a traffic jam at another point for traffic in the entire tunnel to come to a standstill. Using similar logic, a limitation in nasal airflow can limit the efficacy of any of the treatment options other than positive airway pressure therapy.5-7 In addition, nasal obstruction can cause sleep fragmentation, sleep deprivation, and disturbed sleep architecture, and worsen excessive daytime sleepiness.8

There are some cases when decreased nasal airflow, via either severe allergic rhinitis or frank anatomical nasal obstruction, can limit the use of CPAP therapy and thus warrant nasal surgery before CPAP therapy may be effective. However, in many cases, CPAP therapy, especially when used in conjunction with heated humidity, can alleviate nasal congestion and successfully open the airway. This is an advantage that CPAP therapy has over all of the other treatment options, including the Palatal Implant procedure.

CAN THE PALATAL IMPLANT PROCEDURE BE USED AS A COMBINATION THERAPY?

As the success rate of UPPP is relatively low, some interest has arisen as to whether there may be a role for the placement of palatal pillars in the soft palatal tissue remaining following a failed UPPP. One prospective, nonrandomized study of 26 patients with failed UPPP who underwent the Pillar Implant procedure as a revision procedure was performed in patients who had mild to moderate OSA, and presented with recurrence or persistence of snoring after UPPP. Although postoperative snoring levels improved, subjective cure was achieved in 21.7% of patients.9 A similar, more recent prospective, nonrandomized study involving 16 patients with failed UPPP after a 6-month follow-up period also demonstrated a very modest improvement in the AHI from 18.08 +/- 6.02 to 16.8 +/- 5.05 events/h (P = 0.03).10 It is not clear as to what, if any, effect the Palatal Implant procedure has on the combined efficacy when used in conjunction with either CPAP therapy or mandibular advancement devices.

There may possibly be a subset of patients with a diagnosis of snoring or OSA who possess a specific type of oropharyngeal airway or palatal anatomy who are more likely to benefit from treatment with the Palatal Implant procedure than other patients with snoring or OSA. However, a well-designed and executed stratified research study would be required in order to potentially identify such a group of patients.

Currently, there is no practice parameter paper in regard to the use of the Pillar Implant procedure in patients with OSA. Likewise, no published studies are available in regard to the efficacy of the Pillar Implant procedure in patients with moderate to severe OSA, patients with OSA with significant oxygen desaturations, or patients with OSA with significant commonly associated comorbidities such as excessive daytime sleepiness, hypertension, diabetes, congestive heart failure, myocardial infarction, or stroke. Until such data becomes available, it may be advisable to follow practice parameter papers regarding the treatment of sleep-disordered breathing.

Timothy J. Walter, MD, is the author of REM Illumination Memory Consolidation and is currently the co-medical director of Capitol Sleep Medicine Sleep Diagnostic Center at Grove City, Ohio. He can be reached at [email protected]. The opinions and views presented in the article are those of the author and do not necessarily coincide with the point of view of Sleep Review.

REFERENCES

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