The Significance of Peripheral Input

The Significance of Peripheral Input in Patients With Post Surgery Neuropathic Pain: Evaluation of Trigger Point Anesthesia. A Double-blind, Randomized, Controlled Exploratory Study

The investigators want to examine trigger point injections of local anesthetics, in patients with post operative neuropathic pain, determine changes in sensory disturbances such as allodynia, hyperalgesia and thermal sensitivity and examine whether trigger point injections will attenuate pain in rest and activity.

Study Overview

• Status: Unknown
• Conditions: Neuropathic Pain
• Intervention / Treatment: Drug: Ropivacaine

Detailed Description

The presence of cutaneous trigger points in the surgical incision of patients with post-surgery pain has been shown in our pain clinic, all patients have persistent pain for more than 3 month and different sensory disturbances.

Examinations with trigger point injections of local anesthetics have been used to determine the influence of peripheral changes and the significance of afferent input on persistent post-surgery neuropathic pain.

In the present study the investigators will document the influence of cutaneous trigger point injections for both subjective pain experience and objective findings in the area such as allodynia, hyperalgesia and thermal sensitivity. The investigators expect reduction in spontaneous pain intensity and de-crease in peripheral sensory disturbances and will determine the significance of peripheral input in persistent neuropathic pain.

The investigators aim to investigate whether injection of local anesthesia into trigger points compared with placebo (saline) injection will attenuate pain and normalize abnormal sensations, such as hyperalgesia and allodynia. The investigators believe this to be an important investigation to understand the mechanisms behind chronic post-surgery pain.

• Study Type: Interventional
• Enrollment (Anticipated): 12
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Denmark
  • Copenhagen, Denmark, 2400 NV
    • Recruiting
    • Bispebjerg Hospital
    • Contact: Marianne R Saugbjerg, RN, MHH; Phone Number: +45 2145 4462; Email: marianne.roerbaek.saugbjerg@regionh.dk
    • Contact: Finn B Moltke, MD; Phone Number: +45 2116 0444; Email: finn.borgbjerg.moltke.01@regionh.dk

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Age > 18 years old
• Patients with chronic pain (daily VAS pain scores >30 mm) for at least 3 months after knee, shoulder or foot surgery
• Patients with at least one identifiable trigger point in relation to incision from the knee, shoulder or foot surgery. A trigger point is defined as an ar-ea in relation to the incision from surgery, in which a light pressure from a cotton pin radiate pain to the nearby area, and exudes a motor reflex causing withdrawal of the leg
• A written informed consent to participate in the study after having fully understood the contents of the protocol and restrictions

Exclusion Criteria:

• Patients who cannot cooperate
• Patients who cannot understand or speak Danish.
• Patients with allergy to the drugs used in the study
• Patients in treatment with vitamin K antagonists.
• Patients with other pain conditions
• Patients with diabetes

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Ropivacaine injection in trigger points; Ropivacaine injection 1 ml in all trigger points in and around scar after operation in knee, shoulder and foot, one time, duration 3 minutes	Drug: Ropivacaine; Injection of 1 ml Ropivacaine in all trigger points in and around scar. Injection of 1 ml saline in all trigger points in and around scar.; Other Names: Saline
Placebo Comparator: Placebo injection in trigger points; Saline injection 1 ml in all trigger points in and around scar after operation in knee, shoulder and foot, one time, duration 3 minutes	Drug: Ropivacaine; Injection of 1 ml Ropivacaine in all trigger points in and around scar. Injection of 1 ml saline in all trigger points in and around scar.; Other Names: Saline

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in worst pain in rest and in activity	Change in worst pain assessed on a visual analogue scale (VAS, 0-100 mm) at rest and after stair walking/abduction of shoulder, before and after trigger point injections compared to baseline pain score	30 minutes

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in area of sensory disturbances	Area of pin-prick hyperalgesia, using von Frey filament 60 g and brush allodynia, using Somdic brush, assessed pre- and post-injection. Areas identified at a control day between the two intervention days.	30 minutes
Change in warm and cold detection, threshold and tolerance before and after intervention in area with hyperalgesia compared to normal skin	Detection, thresholds and tolerance for cold and heat within the hyperalgesia area compared to normal skin at the contralateral site, before and after trigger point injections. All measures made with Somedic MSA Thermal Stimulator	30 minutes

Collaborators and Investigators

• Sponsor: Bispebjerg Hospital

Publications and helpful links

General Publications

• Wijayasinghe N, Ringsted TK, Bischoff JM, Kehlet H, Werner MU. The role of peripheral afferents in persistent inguinal postherniorrhaphy pain: a randomized, double-blind, placebo-controlled, crossover trial of ultrasound-guided tender point blockade. Br J Anaesth. 2016 Jun;116(6):829-37. doi: 10.1093/bja/aew071.
• Haroutounian S, Nikolajsen L, Bendtsen TF, Finnerup NB, Kristensen AD, Hasselstrom JB, Jensen TS. Primary afferent input critical for maintaining spontaneous pain in peripheral neuropathy. Pain. 2014 Jul;155(7):1272-1279. doi: 10.1016/j.pain.2014.03.022. Epub 2014 Apr 2.
• Haroutounian S, Ford AL, Frey K, Nikolajsen L, Finnerup NB, Neiner A, Kharasch ED, Karlsson P, Bottros MM. How central is central poststroke pain? The role of afferent input in poststroke neuropathic pain: a prospective, open-label pilot study. Pain. 2018 Jul;159(7):1317-1324. doi: 10.1097/j.pain.0000000000001213.

Study record dates

Study Major Dates

• Study Start (Actual): November 20, 2019
• Primary Completion (Anticipated): May 1, 2021
• Study Completion (Anticipated): May 1, 2021

Study Registration Dates

• First Submitted: March 9, 2020
• First Submitted That Met QC Criteria: February 17, 2021
• First Posted (Actual): February 21, 2021

Study Record Updates

• Last Update Posted (Actual): February 21, 2021
• Last Update Submitted That Met QC Criteria: February 17, 2021
• Last Verified: February 1, 2021

More Information

Terms related to this study

• Keywords: Trigger point injection; Post operative pain; Peripheral input
• Additional Relevant MeSH Terms: Nervous System Diseases; Pain; Neurologic Manifestations; Neuromuscular Diseases; Peripheral Nervous System Diseases; Neuralgia; Physiological Effects of Drugs; Central Nervous System Depressants; Peripheral Nervous System Agents; Sensory System Agents; Anesthetics; Anesthetics, Local; Ropivacaine
• Other Study ID Numbers: NP-FM-19

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No