Chronic pain after inguinal hernia repair in children.

BACKGROUND: The prevalence of moderate-to-severe pain after inguinal hernia repair (IHR) in adults is ≈ 10%. Two studies with very long follow-up periods (16.8 and 49 yr, respectively) have, however, suggested that the risk of developing chronic pain is much lower in children. The purpose of the present study was to examine the prevalence of chronic pain 6-48 months after IHR in children. METHODS: Postal questionnaires were sent to 156 children who had undergone IHR between the age of 6 months and 12 yr. The children were asked to recall the duration of postoperative pain, if necessary with help from their parents, and to describe the intensity and character of their pain, if the pain was still present. Children with chronic pain were offered quantitative sensory testing (QST), and a surgical examination, including ultrasound, in order to exclude hernia recurrence. RESULTS: Ninety-eight children, mean (sd) age 7.8 (2.6) yr, answered the questionnaire. Their age at the time of surgery was mean (sd) 4.6 (2.4) yr, and the follow-up period was mean (sd) 3.2 (1.3) yr. Five children (5.1%, 95% confidence interval: 0.75-9.5) had pain located in the inguinal region, and three of these children underwent further examination. There was no hernia recurrence, but QST revealed pinprick hyperalgesia and decreased pressure pain thresholds on the operated side in all three children. CONCLUSIONS: The prevalence of chronic pain after IHR in children is 5.1%, which is lower than the prevalence reported after adult hernia repair.

Chronic pain in adults after thoracotomy in childhood or youth.

BACKGROUND: Chronic pain is common after thoracotomy with reported prevalence rates of 20-60%. The pain may be caused by damage to the intercostal nerves during surgery. Some studies have suggested that young age at the time of surgery reduces the risk of developing chronic pain. So far, no studies have examined if children and adolescents develop chronic pain after thoracotomy. METHODS: Eighty-eight patients, mean (sd) age 39.3 (7.7) yr, who underwent thoracotomy between the age of 0 and 25 yr were asked to recall the duration of postoperative pain and-if pain was still present-to describe intensity and character of pain. In addition, all patients underwent quantitative sensory testing. RESULTS: Fourteen patients (16%) recalled that their postoperative pain had lasted for more than 3 months: one (3.2%) patient in the youngest group (0-6 yr), seven (19.4%) patients in the age group 7-12 yr, and six (28.5%) patients in the age group 13-25 yr (P=0.03). Three out of the 14 patients, who were 11, 11, and 18 yr of age at the time of surgery, still had pain at present. Quantitative sensory testing revealed hypo- and hyperphenomena in most patients, including those with persistent pain. Tactile detection thresholds and pressure detection thresholds were significantly higher on the operated side when compared with the contralateral side (n=88; P<0.001). CONCLUSIONS: The risk of developing chronic pain after thoracotomy seems to be lower if surgery is performed at a young age. Pain after thoracotomy is likely to be of neuropathic origin.

MRI in chronic spinal cord injury patients with and without central pain.

BACKGROUND: Central pain following spinal cord injury (SCI) is common and thought to be related to lesion of the spinothalamic pathways. OBJECTIVE: To examine additional mechanisms of SCI pain. METHODS: Twenty-three SCI patients with traumatic lesions above T10 (14 with central neuropathic pain and 9 without pain) underwent MRI examination. The authors quantitatively assessed extent of cord lesion on axial T2-weighted images as percentage of 1) gray matter, 2) dorsolateral, 3) anterolateral, and 4) dorsolateral columns based on standardized drawings made by a neuroradiologist blinded to patient history. RESULTS: At the level of maximal cord injury, 21 patients had lesions involving the entire cord on axial images except for a small border of lower signal intensity, whereas 2 patients had central lesions. Rostral to the main injury, the first image with an incomplete lesion showed significantly more involvement of gray matter in pain than in pain-free patients. CONCLUSION: Consistent with animal models of SCI, spinothalamic tract lesion together with neuronal hyperexcitability due to lesion of inhibitory interneurons at the rostral end of injury are hypothesized to lead to central pain.