A systematic literature review of intracranial hypotension following chiropractic.

Background: Intracranial hypotension (IH) is caused by a leakage of cerebrospinal fluid (often from a tear in the dura) which commonly produces an orthostatic headache. It has been reported to occur after trivial cervical spine trauma including spinal manipulation. Some authors have recommended specifically questioning patients regarding any chiropractic spinal manipulation therapy (CSMT). Therefore, it is important to review the literature regarding chiropractic and IH.

Objective: To identify key factors that may increase the possibility of IH after CSMT.

Method: A systematic search of the Medline, Embase, Mantis and PubMed databases (from 1991 to 2011) was conducted for studies using the keywords chiropractic and IH. Each paper was reviewed to examine any description of the key factors for IH, the relationship or characteristics of treatment, and the significance of CSMT to IH. In addition, other items that were assessed included the presence of any risk factors, neck pain and headache.

Results: The search of the databases identified 39 papers that fulfilled initial search criteria, from which only eight case reports were relevant for review (after removal of duplicate papers or papers excluded after the abstract was reviewed). The key factors for IH (identified from the existing literature) were recent trauma, connective tissue disorders, or otherwise cases were reported as spontaneous. A detailed critique of these cases demonstrated that five of eight cases (63%) had non-chiropractic SMT (i.e. SMT technique typically used by medical practitioners). In addition, most cases (88%) had minimal or no discussion of the onset of the presenting symptoms prior to SMT and whether the onset may have indicated any contraindications to SMT. No case reports included information on recent trauma, changes in headache patterns or connective tissue disorders.

Discussion: Even though type of SMT often indicates that a chiropractor was not the practitioner that delivered the treatment, chiropractic is specifically cited as either the cause of IH or an important factor. There are so much missing data in the case reports that one cannot determine whether the practitioner was negligent (in clinical history taking) or whether the SMT procedure itself was poorly administered.

Conclusions: This systematic review revealed that case reports on IH and SMT have very limited clinical details and therefore cannot exclude other theories or plausible alternatives to explain the IH. To date, the evidence that CSMT is not a cause of IH is inconclusive. Further research is required before making any conclusions that CSMT is a cause of IH. Chiropractors and other health practitioners should be vigilant in recording established risk factors for IH in all cases. It is possible that the published cases of CSMT and IH may have missed important confounding risk factors (e.g. a new headache, or minor neck trauma in young or middle-aged adults).