Spinal manipulation has been an effective intervention for the management of various musculoskeletal disorders. However, the mechanisms underlying the pain modulatory effects of spinal manipulation remain elusive. Although both biomechanical and neurophysiological phenomena have been thought to play a role in the observed clinical effects of spinal manipulation, a growing number of recent studies have indicated peripheral, spinal and supraspinal mechanisms of manipulation and suggested that the improved clinical outcomes are largely of neurophysiological origin. In this article, we reviewed the relevance of various neurophysiological theories with respect to the findings of mechanistic studies that demonstrated neural responses following spinal manipulation. This article also discussed whether these neural responses are associated with the possible neurophysiological mechanisms of spinal manipulation. The body of literature reviewed herein suggested some clear neurophysiological changes following spinal manipulation, which include neural plastic changes, alteration in motor neuron excitability, increase in cortical drive and many more. However, the clinical relevance of these changes in relation to the mechanisms that underlie the effectiveness of spinal manipulation is still unclear. In addition, there were some major methodological flaws in many of the reviewed studies. Future mechanistic studies should have an appropriate study design and methodology and should plan for a long-term follow-up in order to determine the clinical significance of the neural responses evoked following spinal manipulation.

Hand injury is the second most common work-related musculoskeletal injury among physical therapists (PTs) and other manual therapy professionals such as osteopaths, physiotherapists, chiropractors, acupuncturists and massage therapists. However, the nature and extent of this problem have not been fully explored yet. Therefore, the objective of this study was to review the existing literature published on the prevalence, risk factors, consequences, and prevention of hand injuries among PTs and similar healthcare professionals. The lifetime prevalence of hand injuries was about 15%-46%, and the annual prevalence was reported as 5%-30%. Thumb injuries were found to be the most prevalent of all injuries, accounting more than 50% of all hand-related problems. The most significant risk factors for job-related hand injuries were performing manual therapy techniques, repetitive workloads, treating many patients per day, continued work while injured or hurt, weakness of the thumb muscles, thumb hypermobility, and instability at the thumb joints. PTs reported modifying treatment technique, taking time off on sick leave, seeking intervention, shifting the specialty area, and decreasing patient contact hours as the major consequences of these injuries. The authors recommend that PTs should develop specific preventive strategies and put more emphasis on the use of aids and equipment to reduce the risk of an unnecessary injury.

Spinal manipulation is a manual treatment technique that delivers a thrust, using specific biomechanical parameters to exert its therapeutic effects. These parameters have been shown to have a unique dose-response relationship with the physiological responses of the therapy. So far, however, there has not been a unified approach to standardize these biomechanical characteristics. In fact, it is still undetermined how they affect the observed clinical outcomes of spinal manipulation. This study, therefore, reviewed the current body of literature to explore these dosage parameters and evaluate their significance, with respect to physiological and clinical outcomes. From the experimental studies reviewed herein, it is evident that the modulation of manipulation's biomechanical parameters elicits transient physiological responses, including changes in neuronal activity, electromyographic responses, spinal stiffness, muscle spindle responses, paraspinal muscle activity, vertebral displacement, and segmental and intersegmental acceleration responses. However, to date, there have been few clinical trials that tested the therapeutic relevance of these changes. In addition, there were some inherent limitations in both human and animal models due to the use of mechanical devices to apply the thrust. Future studies evaluating the effects of varying biomechanical parameters of spinal manipulation should include clinicians to deliver the therapy in order to explore the true clinical significance of the dose-response relationship.
Animals ; Humans ; Manipulation, Spinal