Background and Purpose:
Complex regional pain syndrome (CRPS) is a chronic condition affecting at least one extremity that can develop after injury, involving allodynia, constant limb pain, and hyperpathic autonomic and somatic symptoms.1 One essential CRPS treatment is somatosensory desensitization (SD), yet efficacy evidence remains limited.2 This study aimed to assess changes in pain distribution and intensity in treated and untreated limbs, as well as possible somatosensory normalization of proximal non-painful limb regions, after 10 weeks of SD.
The 54 y.o. male patient had an incomplete C5 SCI. Prior to SD, the patient experienced constant searing pain and tactile allodynia in all limbs for 5 years following Type II CRPS diagnosis, despite 18 months of early physical therapy that restored nearly full functional mobility. Quadrilateral involvement permitted researchers to desensitize one upper and one lower limb. The 10-week SD treatment involved progressing coarse materials weekly, applied via self-massage BID. The patient completed pain body diagrams (PBD) with pain distribution score (PDS) calculations applied to PBDs3 to quantify changes in extent of limb pain. Weekly outcome measures included visual analog pain scale (VAS) and allodynia measurements via algometry. Somatosensory changes to all limb areas were measured using Semmes Weinstein monofilaments and 2-point discrimination.
Overall PDS decreased by 23.5% (9.5% for treated limbs, 14.0% for untreated limbs). VAS scores for treated limbs decreased by 5.5cm UE and 2.4cm LE, with untreated limb reductions of 0.3cm UE and 1.2cm LE. Monofilament and 2-point discrimination testing revealed subnormal pretreatment somatosensory thresholds and acuity of non-painful proximal limb areas, that subsequently normalized with corresponding decreases in distal pain. Other posttreatment changes included improved UE grip/pinch strength, axial loading tolerance in all limbs, and allodynia.
Prior literature suggests SD can result in decreased pain in treated limbs, but does not discuss changes in untreated painful areas.4 After 10-weeks of SD, this spinal cord injured patient experienced notable reductions in pain intensity, distribution, and allodynia in all treated and untreated limbs. As pain decreased in more distal areas, somatosenation in proximal, non-painful areas normalized. Findings suggest central neuroplastic changes may occur from SD treatment, possibly involving normalized representation of affected and unaffected areas in the neuromatrix.
1. Harden R, Bruehl S, Perez R, et al. Validation of proposed diagnostic criteria (the “Budapest Criteria”) for complex regional pain syndrome. Pain 2010;150(2):268-274.
2. Freedman M, Greis A, Marino L, Sinha A, Henstenburg J. Complex regional pain syndrome: diagnosis and treatment. Phys Med Rehabil Clin N Am. 2014;25(2):291-303.
3. Allen RJ, Soterakopoulos C, Fugere KJ, Sorbie WK, Oksendahl AL, Looper J. Pain distribution quantification using enhanced 'rule-of-nines': reliability and correlations with intensity, sensory, affective, and functional pain measures. Physiotherapy 2011;97(S1):309.
4. Allen R, Wilson A. Chapter 91: Physical therapy agents. In: Fishman S, Ballantyne J, Rathmell J, Fishman S, eds. Bonica’s Management of Pain. 4th ed. Philadelphia: Lippincott Williams and Wilkins; 2010:1345-1356.
University of Puget Sound
Cook, Lisa; Dullen, Kristen; Hoffman, Jacob; Vento, Megan; and Allen, Roger, "Effects of Desensitization on Pain Distribution and Normalization of Somatosensation in a Patient with Quadrilateral Complex Regional Pain Syndrome" (2016). Physical Therapy Research Symposium. 21.