AUSTIN, Texas — Several factors, including age and other demographic factors, may predict occurrence of chronic pain following surgery, according to data presented here this week.
Kristin Schreiber, MD, PhD, an anesthesiologist and research fellow at Brigham and Women’s Hospital presented her latest research at a poster session of the American Pain Society’s annual conference. She and her colleagues sought to determine risk factors for development of post-operative chronic pain, and in particular, following lumpectomy or mastectomy.
Predictive factors for post-operative chronic pain that were considered in past studies, included age and other demographic factors, as well as pre-operative pain. A retrospective study had determined that psychosocial factors, such as anxiety, depression, catastrophizing and sleep disturbance, correlated with chronic pain experienced one year or longer post-surgery. This study however failed to establish whether pain was causing the psychological issues or whether the opposite was occuring, prompting Schreiber and her colleagues to investigate the issue prospectively by measuring these psychosocial factors prior to surgery.
Quantitative sensory testing, and validating questionnaires to determine occurrence of catastrophizing or depressive behavior were used. In the sensory quantitative tests, Dr. Schreiber asked patients to rate sensitivity to a single pricking stimulus and to pain prick temporal summation, consisting in repetitive pricking.
Pain levels were thus assessed at 2 weeks and 3, 6 and 12 months following surgery. Seventeen percent of patients reported pre-operative pain. Two weeks post-surgery, 60% of subjects experienced pain, levels which leveled off to ~ 32% at the later time points.
Patients were asked to report pain frequency and severity in four body areas affected by the surgery in order to determine the amount of pain burden. The thus-determined pain burden index increased 2 weeks post-surgery, before dropping in the later post-operative stages. Patients who had undergone mastectomy experienced higher pain levels than those who had undergone a lumpectomy procedure, however, lumpectomy patients reported more pain and pain burden at the later time points.
Dr Schreiber and her colleagues also conducted a functional assessment in which they asked patients to determine whether the pain they were experiencing was stopping them from performing regular activities. They found that the functional impact of pain was more prevalent in the early post-operative stages than later on.
As previously reported by other groups, younger subjects experienced higher pain levels than older patients at all time points. Psychosocial and psychophysical tests failed to predict pain in the acute period. However, in the more chronic pain period, the researchers noted pre-operative depression and anxiety as well as quantitative sensory tests to correlate with levels of reported pain.
This study shows that several factors, which can be detected pre-operatively can predict occurrence of chronic pain following surgery. Researchers hope that these factors can be used to identify patients who are at high risk for post-operative chronic pain. This would be useful to preemptively treat this group with e.g. nerve block, pre-operative ketamine or lidocaine, or cognitive behavioral therapy.
Schreiber K, Zinboonyahgoon N, Cornelius M, Edwards R. Acute and subacute postoperative pain after partial and total mastectomy; association with prospectively assessedpsychosocial and psychophysical variables. Presented at: 35th Annual Scientific Meeting of the American Pain Society; May 11-14, 2016; Austin, Texas.