Chronic Pain following C-Section Evaluated with the Short-Form McGill Pain Questionnaire 2 (SF-MPQ-2)
Abstract Number: BP-3
Abstract Type: Original Research
Estimates of the incidence of chronic pain after CS vary widely ranging from 3-18%^1,2. One factor that may contribute to this variability is the lack of standardized and comprehensive approach to evaluate chronic pain in this population. The aim of this study was to utilize the brief pain inventory (BPI)^3 and revised SF-MPQ2^4, a novel comprehensive measure of pain quality, to characterize pain experience in women after CS.
360 women with no history of chronic pain undergoing an elective CS were enrolled. Spinal anesthesia was standardized (bupivacaine 12mg, fentanyl 25µg, morphine 100µg). Post-op pain at rest (R), while sitting (S) and uterine cramping (U) was recorded at 48h. Pain at 8 weeks and 6 months was scored with BPI (3 pain severity questions); pain quality was assessed with SF-MPQ2 (22-items including 6 descriptors each for continuous, intermittent and neuropathic pain, and 4 for affective pain) rated on an 11-point numeric rating scale (NRS). Data are presented as median NRS [quartiles].
Average maternal age was 31±5, with a majority of Caucasians (78%), and primary CS (70%). Pain at 48h was overall mild (NRS-R=2 [0;3]; NRS-S=2 [0;4]; NRS-U=1 [0;3]). At 8 weeks, 334 women (93%) responded, and 34 (10%) complained of pain >0 in the last week (BPI 2 [2;4]); only 8 (2.4%) met the widely accepted criteria of chronic pain of ≥ 4/10 in the last week. At 6 months, 327 women (90%) responded, and 11 (3.4%) still reported some pain (BPI 3 [2;4]). Using SF-MPQ2, neuropathic symptoms were present in 238 women (71%) at 8 weeks, and 138 (42%) at 6 months (Figure). Numbness was the most common neuropathic symptom. The range for other reported pain descriptors was between 0.6-4%. 13 descriptors were never reported at 6 months.
In this prospective longitudinal study, the incidence of chronic pain at 6 months was close to 4%. Using for the 1st time SF-MPQ2 to characterize chronic pain after CS, the most prevalent descriptor was numbness, which was present in 38% of women at 6 months. Other descriptors occurred with a low incidence and included throbbing, tender, cramping, stabbing or piercing pain. As previously described, we found that chronic pain after CS is rare and that characteristics of pain, if present, are mostly neuropathic^5, validating SF-MPQ2 as a useful tool to assess long term pain after CS.
1 Sia, Anesthesiol 2008
2 Kainu, IJOA 2009
3 Cleeland, Pain 1996
4 Dworkin, Pain 2009
5 Loos, Obstet Gyn 2008