Prevalence and Clinical Characteristics of Chronic Post-surgical and Post-traumatic Pain in a Tertiary Level Oral Medicine Clinic

Abstract

Background: Chronic post-surgical and post-traumatic pain (CP-PTP) occurs after surgery or trauma, persisting beyond the healing time, and is localized to the event or dermatome, while other causes should be excluded. The condition appears to be underdiagnosed and undertreated, with little known about its prevalence and characteristics in the head and neck region. Aim: The aim of this study was to determine the proportion, clinical characteristics, events and comorbidities of subjects that fit the ICD-11 CP-PTP criteria in a tertiary level oral medicine clinical service. Methods: A cross sectional study retrospectively reviewing electronic health record charts in the Oral Medicine Clinical Service at the University of Washington was completed between December 1st, 2021 and November 30th, 2022. CP-PTP ICD-11 criteria were applied to all charts that had a pain diagnosis based on ICD-10 billing data. Clinical information was obtained from the Axium electronic health record and scanned documents including a pain questionnaire completed by all new subjects, a pain drawing, Pain, Enjoyment of Life and General Activity (PEG) measure, Graded Chronic Pain Scale (GCPS), the Symptom checklist-90 revised (SCL-90R), and other measures. Descriptive statistics were used to summarize the findings of each variable collected. Results: The CP-PTP prevalence was 16.8% (n=89), occurring after surgery in 71% (n=63), following trauma in 14.6% (n=13), and in 14.6% after concurrent trauma and surgery. The median time subjects were followed in the clinic was 14 months (range 0-210 months). The median age was 60.5 years old and three quarters were female. Pain was present for a median of 60 months (5-years) and individuals saw a median of 9.5 providers for their pain condition prior to presenting to the oral medicine specialty clinic. The most frequent event locations were teeth (70.7%), maxilla/zygoma (11.2%) and temporal-parietal areas. The most prevalent CP-PTP subcategories were following amputation (i.e. root canal therapy and dental extraction), peripheral nerve injury and whiplash (71.9%, 24.9%, 19.1%) respectively. The most common craniofacial diagnoses were myofascial pain and possible posttraumatic trigeminal neuropathic pain in 75.2% (n=67) and 64% (n=57) of the cases, respectfully. At the time of presentation to the clinic, 19.1% (n=17) of individuals had pain localized to the area of the event, 16.8% (n=15) in the head and neck and 56.1% (n=50) had pain in at least one location beyond the head/neck region. Moderate or severe anxiety were present in 30% (n=27) and moderate or severe depression in 47.1% (n=42) of the cases. The pain intensity and impact were 4.45 out of 10, measured with the (PEG) mean score. Conclusions: The prevalence of CP-PTP in the clinical sample was 17%, showing it is a common occurrence in a tertiary care clinic. CP-PTP occurring in the craniofacial region appears to be under-recognized and undertreated with individuals experiencing pain for a long delay before referral to a specialty oral medicine clinic, resulting in subsequent delays and significant suffering before proper treatment was initiated. The most common event was surgery, however, a significant portion of individuals had myofascial pain as well as possible trigeminal neuropathic pain, emphasizing the need to assess for these comorbid conditions in individuals after surgery or trauma. This is the first study to apply the ICD-11 criteria for CP-PTP in a sample of individuals with craniofacial pain in a tertiary care clinic. The use of the ICD-11 criteria for CP-PTP is feasible but streamlining the collection of relevant clinical information may help to classify the cases more accurately.