This review summarised recent case reports of opthalmological adverse effects of upper spinal manipulation (USM). The author concluded that USM is associated with opthalmological adverse effects of unknown frequency and that research is required to reliably determine the frequency. Despite limitations in the reporting of the review methods, the author's conclusion appears reasonable given the reliance on evidence from case reports.

To summarise recent case reports of opthalmological adverse effects associated with upper spinal manipulation (USM).

MEDLINE, EMBASE, the Cochrane Library, AMED and CISCOM were searched for articles published in any language between 1995 and April 2003; the search terms were reported. In addition, the author's personal files were searched, experts were contacted and reference lists were screened.

Case reports were eligible for inclusion in the review.

Studies of USM were eligible for inclusion. Where the included studies provided details of the type of USM employed, these included cervical manipulation, high-velocity rotational thrust of the cervical spine, rapid rotational neck manipulation, Shiatsu massage of the upper neck and rotatory chiropractic manipulation. USM was performed mostly by chiropractors; several studies did not report who performed the USM or what type of USM was used.

Inclusion criteria for the participants were not specified. The included studies were generally in middle-aged men and women. In most studies, where details were reported, the participants had consulted practitioners complaining of neck and shoulder pain or stiffness; others had consulted with headache or chronic lower back pain and several did not state the reason for the consultation. The reports were mainly of participants with unremarkable past medical histories; one report was of a patient with a previous transient ischaemic attack.

Studies that reported opthalomological adverse effects were eligible for inclusion. The review assessed adverse events, complications and symptoms, treatment required as a result of the adverse event, final outcome, and the likelihood of causality based on information presented in the original report.

The author appears to have evaluated all case reports.

The author did not state that he assessed validity.

The author did not state how the data were extracted for the review, or how many reviewers performed the data extraction. For each study, the adverse events, complications and symptoms were extracted and the causality determined.

Details of the individual studies were tabulated and the studies were combined in a narrative.

Differences were apparent from examination of the data extraction table.

Fourteen case reports were included (n=14).

Opthalmological adverse effects included nystagmus, Wallenberg's syndrome, loss of vision, hemianopsia, ophthalmoplegia, diplopia, Horner's syndrome and ptosis. In seven case reports the symptoms were of sudden onset. In several cases the impairments were permanent.

In most reports the causality of the relationship between USM and opthalmological adverse effects was judged as certain (six case reports) or likely (six case reports). Eight case reports involved dissection of an artery (carotid, vertebral or intracranial).

USM is associated with opthalmological adverse effects but the frequency of them is unknown. Research to reliably determine the frequency is required.

The review addressed a clear research question that was defined in terms of the intervention, outcomes and study design; eligible participants were not defined. Five databases were searched and attempts were made to reduce language and publication bias. It was not clear why the search focused on reports published after 1995. Only one reviewer selected studies and this lack of duplication might have led to errors and bias. The methods used extract the data were not described, so it is not known whether any efforts were made to reduce reviewer errors and bias. Given the nature of the studies, a narrative synthesis was appropriate. The author discussed limitations of the evidence, but there were also limitations in the reporting of review methods. However, the author's conclusion is reasonable in view of the reliance on evidence from case reports, and recommendations for further research are justified.

Practice: The author stated that opthalmologists should be aware that USM can be associated with serious opthalmological complications.

Research: The author stated that well-conducted research is urgently required to determine the frequency of opthalmological adverse effects and the risk-to-benefit ratio associated with USM.

1. Rothwell DM, Bondy SJ, Williams SJ. Chiropractic manipulation and stroke: a population-based case-control study. Stroke 2001;32:1054-60. 2. Smith WS, Johnston SC, Skalabrin EJ, Weaver M, Azari P, Albers GW, et al. Spinal manipulative therapy is an independent risk factor for vertebral artery dissection. Neurology 2003;60:1424-8.

This record is a structured abstract written by CRD reviewers. The original has met a set of quality criteria. Since September 1996 abstracts have been sent to authors for comment. Additional factual information is incorporated into the record. Noted as [A:....].