Comprehensive Pain Programme to Determine Mechanism of Transition of Acute to Chronic Postsurgical Pain (TAHP)

KK Women's and Children's Hospital

Status: Completed

Conditions: Anaesthesia; Chronic Pain; Genetics Predisposition

Treatments: Other: pain testing

Study type: Interventional

Funder types: Other

Identifiers

NCT02025153

2013/512/D

Details and patient eligibility

About

To determine whether central sensitization is a mechanism of CPSP (chronic postsurgical pain) in women who will develop CPSP compared to women with no CPSP after hysterectomy. This mechanism is illustrated by a higher pain score in experimental pain models such as tonic heat stimulation, increased evoked mechanical temporal summation and increased wound hyperalgesia.

Full description

Chronic pain affects 9% of Singapore population resulting in major socioeconomic burden. Chronic postsurgical pain (CPSP) that persists for over 3 months could be related to nerve injury making this a strategic model to study the transition of acute to chronic pain. CPSP occurs in up to 50% after surgery and up to 32% after hysterectomy. Over 600000 hysterectomies were performed in the US in 2003 making CPSP a significant problem.

Investigators will perform this prospective cohort study to determine whether increased central sensitization and negative psychological experience are involved in the transition of acute to chronic pain after hysterectomy. Investigators will recruit 444 women undergoing hysterectomy and employ validated physical pain testing including tonic heat stimulation, mechanical temporal summation and wound hyperalgesia which had been shown to be related to central sensitization. Pain catastrophizing (negative thoughts of pain) and state trait anxiety scoring will be assessed for the impact of negative cognitive-affective experience on CPSP. A phone survey will be performed at 4 months to determine the primary outcome of CPSP. Arterial spin labeling will be used to delineate cerebral blood flow using arterial spin labeling, functional connectivity and structural connectivity to evaluate insula-anterior cingulate cortex differences in 30 women with CPSP compared to 30 women without CPSP.

In addition to evaluating whether central sensitization, negative psychological experience and activation of brain regions are different in women with CPSP after hysterectomy, the results of this study will elucidate potential mechanisms of CPSP development that will guide in future studies on potential novel therapeutic targets.

Enrollment: 216 patients

Sex: Female

Ages: 21 to 70 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Anthropometric profile within the following range: age 21-70 yr, American Society of Anesthesiology status I and II women
• Benign condition such as fibroids or adenomyosis
• Abdominal or laparoscopic hysterectomy

Exclusion criteria

• Vaginal hysterectomy
• being pelvic pain
• Failure to adequately determine tonic heat stimulation and mechanical temporal summation
• History of drug dependence or recreational drug use
• Allergy to any study drugs

Trial design

Primary purpose: Diagnostic

Allocation: Non-Randomized

Interventional model: Single Group Assignment

Masking: None (Open label)

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216 participants in 3 patient groups

Cohort

Other group

Description:

pain testing. All 444 subjects enrolled in the study. Subjects will receive preoperative physical (tonic heat stimulation, mechanical temporal summation and wound hyperalgesia), psychological (State Trait Anxiety Inventory, Pain Catastrophizing Scale), and genetics test; postoperative pain score assessment at 24, 48 hours; postoperative wound hyperalgesia in open abdominal hysterectomy at 72 hours; and phone survey for CPSP at 4 months.

Treatment:

Other: pain testing

Chronic Post-surgical Pain

Other group

Description:

pain testing. physical testing, psychological testing, genetics testing and functional brain imaging

Treatment:

Other: pain testing

No Chronic Post-surgical Pain

Other group

Description:

pain testing. physical testing, psychological testing, genetics testing and functional brain imaging

Treatment:

Other: pain testing