Francesca Galiano
26/09/2022 - Last update 04/01/2023

Olivier Jacq, Isabelle Arnulf, Thomas Similowski, Valérie Attali | Year 2017

Upper airway stabilization by osteopathic manipulation of the sphenopalatine ganglion versus sham manipulation in OSAS patients


Obstructive sleep apnoea syndrome (OSAS)

Type of study:

Randomized controlled trial

Date of publication of the study’:



Purpose of the study

  • Objective: to evaluate the effects of OMT of the sphenopalatine ganglion in case of OSAS
  • Measured outcomes:
    • Primary: percentage of people who presented increased pharyngeal stability (defined by a variation of critical closing pressure of the upper respiratory tract of at least -4cmH2O) when awake, 30 minutes after the intervention
    • Secondary: percentage of people who showed increased pharyngeal stability 48 hours after the intervention, variation in critical closing pressure in absolute values, sleepiness on the Epworth scale and snoring
    • Further: lacrimation though Schirmer’s test, induced pain through Visual Analog Scale (VAS) or sensations experienced during OMT


  • Numbers: 9 people (2 female and 7 male, mean age 57 years)
  • Criteria of inclusion: adults (age ≥18 years), with OSAS and apnoea-hypopnoea index included between 15 and 45, recruited in a specialized center.
  • Criteria of exclusion: nocturnal treatment with CPAP or mandibular advancement tools that could not be interrupted for the duration of the study, complete nasal obstruction, BMI > 40, treatment with serotonin reuptake inhibitors.
  • Groups of study: 2 groups obtained by randomization
    • Group 1: OMT first, followed by sham treatment after 21 days, 4 people
    • Group 2: sham treatment first, followed by OMT after 21 days, 5 people
    • On the average the participants showed an apnoea-hypopnoea index of 31.0
    • Only 7 people were analyzed for the primary outcome

Interventions and evaluations

  • Evaluation of awake subjects at baseline, 30 minutes and 48 hours after each intervention critical closing pressure of the upper respiratory tract (defined as the negative pressure beyond which the airways collapse), sleepiness on the Epworth’s sleepiness scale and snoring through simple questions
  • Evaluation of the induced pain through VAS from 1 to 10 cm, of induced lacrimation in both eyes through Schirmer’s test and of the experienced sensations through a short interview (simple “Yes/No” questions) 30 minutes after each intervention
  • Evaluation of recognition of OMT through the question “Which manipulation was the active one?”
  • 1 OMT session and 1 sham treatment session, distanced by 21 days from one another, applied to the sphenopalatine ganglion (the left one first and the right one second, in each session)
    • the person treated had to open the mouth and shift the mandible laterally towards the treated ganglion
  • OMT: pressure applied to the ganglion with the fifth finger of the hand in different phases (first towards the pterygoid process until relaxation of the external pterygoid muscle, and then in the pterygopalatine fossa until release of the surrounding tissues)
  • Sham treatment: pressure applied to the mucosa adjacent to the last homolateral molar with respect to the treated ganglion
  • OMT and sham treatment performed by an osteopath
  • People treated with CPAP or mandibular advancement stopped treatment temporarily 1 week before each surgery, and then resumed it after the evaluation carried out after 48 hours


  • Primary outcomes: 30 minutes after the two interventions, the number of people who responded to OMT was statistically significantly greater than the number of those who responded to sham treatment (5 vs 0).
  • Secondary outcomes: after 30 minutes, the critical closing pressure decreased by a mean -4,5cmH2O with OMT while increased by +1,7cmH2O with sham treatment, with a variation, unfortunately, not statistically significant. After 48 hours, on the other hand, there was no statistically significant variation although 4 people responded to OMT against 1 responding to sham treatment. However, compared to the beginning of the study the critical closing pressure dropped by a mean -9,2cmH2O with OMT, a statistically significant result. With regard to sleepiness, there was no significant difference between the two interventions. About snoring, while there was no variation after sham treatment, 3 out of 6 people reported a decrease in the intensity of snoring after OMT.
  • Further outcomes: after the sham treatment none of the participants experienced pain, while after the OMT all reported acute but tolerable pain (8 out of 10). Likewise, lacrimation increased starkly after OMT, while it decreased after sham treatment. Also, many more people reported some kind of sensation after OMT compared to sham treatment, in a statistically significant manner. Amongst the others: feeling of mouth opening, better breathing from the nose, light paresthesia, teste of blood in the mouth with no bleeding, relaxation, fatigue. Of the 9 participants, 3 stated not to have been able to recognize the active treatment while the other 6 failed to identify it.
  • Further analyses: the order on the interventions does not seem to have influenced any of the outcomes.


OMT showed that it can act on airway stability in awake subjects, showing a result that the literature proved important from the clinical point of view (already a variation of -3cmH2O indicates an improvement). Potentially, OMT may have produced its effects through an autonomic parasympathetic neuromodulation (which in a couple of patients may have also induced a resolution of a headache and a sinusitis).

The interview with the people treated showed how the organization of the study managed to hide which one was the OMT and which one the sham treatment, thus reducing the placebo/nocebo effect linked to possible expectations. Unfortunately, the limited number of people prevented a significance in other results. More robust studies on larger samples are therefore needed. In addition, studies are needed to evaluate the variation in critical closing pressure also during sleep, in order to have a better idea of the actual usefulness of OMT in case of OSAS.

The review of Osteopedia

By Marco Chiera

Strengths: first study evaluating OMT on an objective parameter linked to the stability of the upper respiratory tract; definition of a precise primary outcome with clinical relevance on which to calculate the sample size (how many people to recruit); good description of the intervention as well as of the evaluations; it was checked whether people recognized which one of the two intervention was the OMT and which one the sham treatment. Clinically significant result and good discussion of the results. Interesting use of qualitative evaluation in relation to the intervention, as it can help practitioners understand what patients might feel and consequently make sense of these feelings.

Limits: it is not clear how the sample size was obtained, as trying to use the instrument indicated by the authors results in a sample size greater than 9, which is the value that the authors actually considered. In fact, this small sample explains the meaninglessness of some of the results, which could, instead, have been meaningful with a larger sample size. Moreover, it is not clear whether the effect of the order of the interventions on the outcome has been adequately assessed.

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