SITE-SPECIFIC VERSUS DIFFUSE TREATMENT/PRESENTING SEVERITY OF OBSTRUCTIVE SLEEP APNEA

 

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The past several years have seen a plethora of novel and technologically ingenious procedures (both nonsurgical as well as surgical) developed for treating upper airway obstructive pathology.

Recent modifications to already-existing nonsurgical procedures have produced changes in continuous positive airway pressure devices (auto-titrating CPAP), as well as changes in design and construction of oral appliances (patient-adjustable, custom-made oral appliances), and most recently-OPAP. Despite the allure to nonsurgical therapy, many patients continue to find tolerance and long-term compliance to these devices less than optimal, and hence the desire (on the part of patients and sleep-treating physicians) for surgical therapy becomes apparent.

From a surgical perspective, hyoid advancement and suspension procedures, genioglossus skeletal advancement, tongue-base suspension sutures (Repose Procedure), Somnoplasty Radiofrequency Volumetric Tissue Reduction (of the inferior nasal turbinates, tongue-base, and most recently-tonsils), and coblation technology all have been directed at tongue-base, nasal, and hypopharyngeal obstruction; while CAPSO (Cautery-Assisted Palatal Stiffening Operation), the uvulopalatal flap, Woodson's procedure, traditional UPPP, and somnoplasty of the soft palate have all been directed towards relieving soft palate elongation and vibration (snoring), or for treating retropalatal obstruction.

Against this backdrop exists the more ``major'' surgical procedures: 1) jaw-advancement (telegnathic) surgery, considered by many-while more so invasive- to be the most beneficial in terms of affecting volumetric expansion of the upper airway (at multiple levels) in one surgical procedure; and 2) tracheostomy-still the surgical gold standard in terms of relieving severe forms of OSA and bypassing severe upper airway obstruction.

Many of the above mentioned clinical procedures, however, are currently being offered to patients in the absence of concrete and validated long-term studies. At least in the case of the newer radiofrequency devices, these technologies nevertheless do tempt patients with the potential for treating a very difficult upper airway anatomic problem in a minimally invasive (and potentially less risky) fashion than major surgery.

When to utilize these newer treatments is still subject to much debate, as no meaningful long-term, randomized, prospective studies have yet been performed (and ethically can possibly never be performed). Just as importantly, determining where these ``newer technologies'' fit into existing surgical algorithms is yet to be ascertained.

The first surgical algorithm developed for treatment of OSA was by Drs. Riley and Powell at the Stanford University Sleep Center. This step-wise algorithm is based upon the presenting level of fixed-point apparent anatomic obstruction (i.e., site-specific therapy). Despite this being a subjective call on the part of the surgeon, the algorithm is well known throughout the surgical sleep field, and is still considered to be the ``gold standard'' for guiding the surgeon's thought process during the critical decision-making interval.

Several recent publications (produced primarily by oral and maxillofacial surgeons) have caused many to ponder the need, however, for step-wise surgical treatments in the face of more severe forms of obstructive sleep apnea. Proponents of this alternative treatment suggest that in patients with more severe forms of OSA, jaw advancement surgery (diffuse therapy) unto itself may be the treatment of choice for these patients, eliminating the need for multiple procedures and anesthetics (with their attendant risks). These publications have also exposed the rift that exists between these competing specialties within the surgical sleep community, and have led to questions of bias within the respective specialties (and their existing literature).

It must be remembered, however, that all surgeons are influenced by their education and professional affiliation, as well as acknowledge that the field of sleep surgery is a relatively young field. Most importantly, surgeons are influenced by individual past training and experience.

More recent research into the pathophysiology surrounding OSA has revealed that patients have individual anatomy and varying locations of airway obstruction (i.e., obstruction is often seen less as a ``fixed point'', but rather as a ``dynamic'' process). Current algorithms, however, as mentioned above, are based on ``fixed-point'' or ``site-specific'' therapy, and their application towards the ``dynamic'' pattern or process may be limited.

Even more so, current algorithms ignore the presenting severity of upper airway obstruction as a basis for directing needed surgical therapy. In this light, we must acknowledge that the clinician's ability (i.e., clinicians of all specialties) to (in reality) diagnose dynamic site(s) of upper airway obstruction is limited with current technology, and that no ``cook-book'' solution to an individual's OSA problem necessarily exists.

Examination of the continuum of upper airway narrowing may reveal a clue to the above dilemma: patients with more subtle and mild presenting forms of OSA are generally felt to possess less severe forms (or more localized forms) of upper airway narrowing (milder forms of OSA are often felt to be more amenable to site-specific therapy), while patients with more severe forms of OSA are often felt to suffer from more diffuse (or multi-level) forms of upper airway involvement (increased severity of OSA typically due to more diffuse airway narrowing (multi-level) (see Figure [1]). From this simplistic approach, milder cases, theoretically, may generally be considered to be more amenable to site-specific (focal) therapy, whereas the more severe the degree of upper airway involvement- the more ``diffuse'' a treatment is often required to eliminate the OSA.

Ignorance and/or avoidance of the above has generally led to surgical disasters or misadventures in the past: Attempts at treating milder forms of OSA with diffuse treatment may be ``overkill'' and involve increased risks. On the other hand, attempts at treating more severe forms of OSA with site-specific therapy typically leads to multiple procedures and multiple anesthetics (with attendant increased risks, side-effects, and morbidity) and generally have not been well tolerated.

The importance of choosing the proper initial surgical procedure becomes increasingly apparent when one considers the importance of patient ``drop-out'' from treatment algorithms; unexpected and prolonged post-surgical pain experienced by the patient is usually quoted as the primary reason negating the desire for additional surgical procedures on their part. Whatever the reason, the refusal of the patient to pursue additional needed surgical therapy (after initial unsuccessful upper airway surgery [when shown by polysomnography to be indicated]), should be considered detrimental to their long-term well-being. ``Stage I therapy'' is too often ``The Final Stage therapy.''

Recognition of these principles however, is not found in the existing surgical literature. In fact, the existing surgical algorithms largely ignore the presenting severity of a patient's OSA, and focus too intently on the presenting level of anatomic obstruction (without considering patient drop-out). As mentioned above, current technologic limitations compromise our ability to determine the true site of obstruction, and make this a very subjective assessment). New technologies hopefully may soon eliminate the subjective nature of this exam.

It is time that new surgical algorithms address this oversight. Perhaps it is time that treating sleep physicians (and surgeons) consider not only the subjective assessment of site of anatomic obstruction when formulating their treatment plan, but just as importantly, consider the presenting severity of disease as a guide in determining aggressiveness of surgical therapy. Perhaps when working together as a team (and not as competitors) the overall success rate of initial surgical therapy will be improved, with diminished need for additional (or follow-up) surgical procedures, improved patient acceptance of treatment, and improved patient care.