Impact of osteopathic manipulative techniques on the management of dizziness caused by neuro-otologic disorders: systematic review and meta-analysis

Methods

• Analized articles: 12
• Search string: a combination of multiple terms, free or MeSH, coming from the osteopathic literature, from symptoms of lack of balance and neuro-otological conditions. These terms emerged through discussions with clinical experts and librarians.
• Criteria of inclusion: Randomized controlled studies (RCTs), prospective or retrospective observational studies; adult participants with symptoms of dizziness caused by neuro-otological disorders. Studies where OMT or similar techniques have been compared to a control intervention, in the specific one of the following: sham treatment, standard of care or non-drug therapy (eg, exercises or behavioral therapies).
• Criteria of exclusion: studies on dizziness resulting from vascular, neoplastic or malignant causes, epilepsy, peripheral neuropathies, postural dysfunctions without neuro-otological components; studies focusing on cardiovascular symptoms, dizziness caused by drugs, psychological causes, vascular malformations or medical causes. Studies without control interventions and in which the authors reported aggregate outcomes.

Characteristics of the studies

• 11 RCTs
• 1 observational study
• 8 studies on OMT
  • 4 studies on articulator OMT
  • 2 studies on high-velocity low-amplitude techniques
  • 1 study on craniosacral OMT
  • 1 study on on progressive inhibition of neuromuscular structures
• 6 studies on OMT analogous techniques
• 6 studies did not allow or record the use of drugs to manage dizziness at the same time of the treatment
• all studies were considered of medium-low quality, with 2 high-risk bias studies, according to the GRADE standard and the bias risk tools of the Cochrane Collaboration (ROB-modified for RCT and ROBINS-I for observational studies)

Participants

• Number in the smallest study: 9 in the OMT group and 19 in the control group
• Number in the largest study: 86
• Total: 367, of which about 180 in the OMT groups and 180 in the control groups
• Mean age: from 33 to 73 years

Interventions and evaluations

• Assessment of disability associated with dizziness via DHI, severity and frequency of dizziness, risk of falls, quality of life and return to work.
• Evaluation of drop-out rate, abandonment due to ineffective treatment or adverse events.
• OMT: articulatory, high-speed low-amplitude, craniosacral and progressive inhibition of neuromuscular structures techniques.
• Similar techniques: articular techniques similar to low-speed and moderate-amplitude techniques; chiropractic techniques, physiotherapy, massage.
• Control: sham treatment, standard of care, drugs, counseling, vestibular rehabilitation.

Results

• Primary outcomes:
  • Dizziness related disability: 3 studies showed that the OMT group reported a reduction in the DHI score. In particular, the articular OMT techniques showed a high degree of evidence in obtaining such a result compared to the control interventions, while for the other techniques too much heterogeneity (diversity) was reported between the studies.
  • Severity of dizziness: 4 studies showed that the OMT group reported a reduction in the severity of the symptoms of dizziness. In particular, the articular OMT techniques showed moderate evidence in obtaining this result compared to the control interventions, while for the other techniques too much heterogeneity amongst the studies was observed. However, 1 cranial OMT study showed a greater improvement in symptoms compared to the sham intervention.
  • Frequency of dizziness: 3 studies showed moderate evidence of articular OMT in reducing the frequency of dizziness compared to control interventions. There were no studies that evaluated other techniques.
  • Risk of falls: analysis of 3 studies showed that cranial OMT favored a lower risk of falls compared to diphenhydramine.
  • Quality of life: 1 study reported an improvement in mental, but not physical, quality of life (scores measured by SF-36 questionnaire), obtained through articular OMT.
  • Back to work: none of the studies evaluated this outcome.
• Secondary outcomes:
  • Drop-out rates: 3 studies showed a greater association, however of low quality and not significant, between articular OMT and drop-out rate compared to the control groups. Further analysis considering all OMT techniques did not show any connection to the drop-out rates of the participants.
  • Adverse events: 6 studies analysed the adverse effects of the OMT treatments. Only in 3 studies have some problems emerged. In particular, increased cervical pain, headaches (both OMT and control group), back pain and a sense of feeling unwell (only in the OMT group) have been reported. Only one person left a study with a post-OMT adverse effect, while 7 people in a control group left the study due to ineffectiveness of the intervention (sham treatment).

Discussion

The review shows that OMT and similar techniques can be used as interventions to manage dizziness due to neuro-otological problems. In particular, articular OMT was found to have moderate or high evidence in reducing disability, severity, and frequency of symptoms.

It should be pointed out that, due to the characteristics of the studies, an appropriate meta-analysis could be carried out only for the articular OMT and for these outcomes. For other types of osteopathic techniques and other outcomes, the diversity of the studies was too high to effectively aggregate the effects detected.

However, based on current scientific literature, findings on disability and symptoms related to dizziness can most likely improve quality of life, promote return to work and reduce psychological stress, the use of drugs, the perception of disability and restrictions in movement. In this regard, the finding that OMT has improved the psychological but not physical quality of life may derive from the strong physical disability that vertigo can cause, a result in line with orthopedic studies on the subject. Certainly, such a result points to the need for further studies addressing the condition of dizziness from a global point of view, namely considering the person as a mind-body unit.

With regard to adverse events, OMT showed to be a safe therapy, as negative post-treatment symptoms were few, minor and only one person dropped out of the study because of them. This evidence is certainly useful to be able to properly advise patients on the usefulness of OMT as an additional treatment of dizziness.

Of course, the current review has some limitations. On the one hand, several studies showed a high risk of bias and a low “power” (low ability to detect an effect when it actually occurs, typically due to a low number of participants). On the other hand, the definition of dizziness due to neuro-otological causes was not very clear in the analyzed studies, which may have led to considering studies that worked on different conditions.

In addition, since different manual interventions may use similar techniques differently, the results obtained may not be generalizable. Finally, given the characteristics of the studies, it was not possible to carry out an in-depth meta-analysis of the relationship between OMT and other interventions.