In the study “Physical Therapy in the Treatment of Central Pain Mechanisms for Female Sexual Pain” the authors provide a detailed explanation and walk-through of treating female sexual pain using a biopscyhosocial approach.
In the evaluation section of the article, they share some powerful statistics as it relates to the presence of central pain mechanisms and sexual pain:
- There’s a 30:1 odds ratio that a patient is presenting with central pain mechanisms when the patient presents with disproportionate, non-mechanical pain including hyperalgesia and allodynia
- There’s a 27:1 odds ratio of central mechanisms when the pain persists beyond the expected timeframe for healing (12-16 weeks)
- 15:1 odds ratio of central mechanisms with the presence of diffuse pain
- The presence of fear avoidance and catastrophizing results in 7:1 odds ratio of central mechanisms.
Given the significance of these numbers it’s necessary to truly identify the cause of a patient’s pain. If a patient with pelvic pain walked in the door with these signs and symptoms, we would be remiss to focus on a tissue-based treatment program when the odds are so high that there is a central mechanism present.
I reflected on the challenge of properly identifying a patient’s primary pain generator. Although familiar with key signs of central sensitization, it’s easy for things to get muddled quite quickly in the clinic and revert back to a tissue-based treatment approach with patients who require a biopsychosocial treatment approach.
Identifying Central Pain Syndromes
In a Delphi survey study by Smart et al., they sought to identify the clinical indicators associated with nociceptive, peripheral neuropathic and centrally mediated musculoskeletal pain. It’s a great study that derived expert consensus-derived lists of clinical criteria regarding classifying musculoskeletal pain.
Their study identified the top 6 subjective findings relating to central pain include:
- Disproportionate, non-mechanical, unpredictable pattern 5 of pain provocation in response to multiple/non-specific aggravating/easing factors.
- Pain persisting beyond expected tissue healing/pathology recovery times.
- Pain disproportionate to the nature and extent of injury or pathology.
- Widespread, non-anatomical distribution of pain.
- History of failed interventions (medical/surgical/therapeutic).
- Strong association with maladaptive psychosocial factors (e.g. negative 4 emotions, poor self-efficacy, maladaptive beliefs and pain behaviours, altered family/work/social life, medical conflict).
The top four objective findings related to central pain identified were:
- Disproportionate, inconsistent, non-mechanical/non-anatomical pattern of pain provocation in response to movement/mechanical testing.
- Positive findings of hyperalgesia (primary, secondary) and/or allodynia and/or hyperpathia within the distribution of pain.
- Diffuse/non-anatomic areas of pain/tenderness on palpation.
- Positive identification of various psychosocial factors (e.g. catastrophization, fear-avoidance behaviour, distress).
We’ve pulled together the top ranked subjective/objective findings reported in the study into an easy-to-use table format that can be downloaded from our resource section here.
Introducing the Central Sensitivity Inventory
In the study they highlight the use of the Central Sensitivity Inventory (CSI), a tool I was unaware of. This tool was published in 2012 with the purpose of providing a single self-report instrument that identified symptoms associated with central sensitization and the quantified the degree of those symptoms. As Carolyn and Sandra share, this can be a helpful tool for physiotherapists to identify the presence of central pain mechanisms.
The authors of the CSI outline the clinical goal of this screening instrument: “to help better assess symptoms thought to be associated with CS in order to aid physicians and other clinicians in syndrome categorization, sensitivity, severity, identification and treatment planning, to help minimize, or possibly avoid unnecessary diagnostics and treatment planning.”
There are two parts to the measure. Part A consists of 25 statements relating to current health symptoms. Each item is measured using a 5 point like scale with Never (0), Rarely (1), Sometimes (2), Often (3), and Always (4). This results in a cumulative score of 100. The higher the score the higher the likelihood of central sensitization. In a study by Neblett et al, they identified a clinically significant level of 40 as providing both good sensitivity and specificity for the presence of central sensitization syndrome.
Clinical Application
Having the patient complete the CSI could prove to be a useful tool for not only the clinician, but also for the patient. Understanding the source of the muscolskeletal pain can be an important education tool.
I’d encourage you (as will I) to begin using the CSI in your patients who you suspect of having a centrally mediated pain presentation. Along with this I’d review the subjective and objective criteria identified in the delphi study.
Including the use of the patient using the Tampa Scale of Kinesiophobia (TSK) and the Pain Catastrophizing Scale (PCS) can help with further evaluation and treatment planning of the patient.
Improving our confidence regarding the source of the pain can give us some additional confidence in our treatment planning and will provide some additional tools to help us in our education with patients.
