Trigger Point Injections for Post-Mastectomy Pain Syndrome

Trigger Point Injections for Post-Mastectomy Pain Syndrome: A Double-Blind Randomized Controlled Trial With Intention-to-Treat Analysis

Post-Mastectomy Pain Syndrome (PMPS) is a chronic pain that persists for more than three months after a surgical breast procedure. It has 11-70% incidence in patients that underwent a breast surgery. It consists of mixed pain, frequently associated with myofascial pain, an specific type of muscular pain. Trigger point injections (TPI) are classically used for the treatment of myofascial pain in other painful conditions. However, there are no controlled trials assessing the efficacy of TPI in the treatment of PMPS. The intervention objective is to assess the efficacy of TPI in patients with PMPS, when associated with a comprehensive rehabilitation program and pain management.

Study Overview

• Status: Active, not recruiting
• Conditions: Breast Cancer; Myofascial Pain Syndrome; Trigger Point Pain, Myofascial; Post-mastectomy Pain Syndrome
• Intervention / Treatment: Procedure: Trigger point injection; Other: Comprehensive Rehabilitation program; Procedure: Subcutaneous saline injection

Detailed Description

INTRODUCTION: Post-Mastectomy Pain Syndrome (PMPS) is a chronic pain that persists for more than three months after a surgical breast procedure. It has 11-70% incidence in patients that underwent a breast surgery. It consists of mixed pain, frequently associated with myofascial pain. Trigger point injections (TPI) are classically used for the treatment of myofascial pain in other etiologies. However, there are no controlled trials assessing the efficacy of TPI in the treatment of PMPS

OBJECTIVE: Assess the efficacy of TPI in patients with PMPS, when associated with a comprehensive rehabilitation program and pain management.

METHODS: Double-blind randomized controlled trial with intention-to-treat analysis. Both groups will undergo standard of care delivered by Physiatrist blinded to group allocation. Active group will undergo TPI with 1% lidocaine in each identified trigger-point, weekly, for three consecutive weeks. Control group will undergo subcutaneous saline injection superficial to the same trigger points, with the same frequency and number of sessions. Primary outcome is the mean difference between groups for pain levels, as assessed by Visual Numeric Scale (VNS), from baseline to 3 months after the procedure.

STATISTICAL ANALYSIS: Difference between groups at baseline, one and three months after injection, using Analysis of Covariance (ANCOVA) for the following outcomes: VNS; Presence of active trigger points, Pressure pain threshold (PPT); Short-Form McGill Pain Questionnaire (SF-MPQ); Neuropathic Pain Symptom Inventory (NPSI); Disabilities of the Arm, Shoulder and Hand Questionnaire (DASH); Range of motion (ROM) of affected shoulder, for abduction and external rotation; adverse events; use of pain medication.

Total sample size is 120. Alpha=5%, power=80%.

• Study Type: Interventional
• Enrollment (Actual): 72
• Phase: Phase 2

Contacts and Locations

• Study Contact: Name: Victor Figueiredo Leite, MD; Phone Number: +5511991613139; Email: contato@drvictorleite.com

Study Locations

• Brazil
  • São Paulo, Brazil
    • Instituto do Câncer do Estado de São Paulo
  • São Paulo
    • Barretos, São Paulo, Brazil
      • Hospital de Cancer de Barretos

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Breast cancer patients.

• PMPS diagnosis, as per Wisotzky et col.

  • Pain > 3 months over breast, chest wall or shoulder ipsilateral to surgery.
• Pain Visual analog Scale (VAS) ≥4.
• At least one active trigger point in the following muscles: pectoralis major, superior trapezius, serratus anterior, levator scapularis, latissimus dorsi, infraspinatus

Exclusion Criteria:

• Current radiation therapy or time since completion < 3months.
• Allergy to lidocaine or other local anesthetics
• Active infection over injection sites
• Unavailability to be at the hospital during study intervention.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Active; 3 weekly sessions of TPI. Participants will undergo 1mL injections of 1% lidocaine in the muscles identified with either active or latent trigger points at the initial assessment. The same muscles will be injected at all procedures.	Procedure: Trigger point injection; 1mL injections of 1% lidocaine in the muscles identified active trigger points at the day of intervention (pectoralis major, serratus anterior, levator scapulae, latissimus dorsi, infraspinatus).; Other: Comprehensive Rehabilitation program; Patients in both groups will undergo standard of care rehabilitation delivered by a Physiatrist, which may include Physical Therapy, Occupational Therapy, Exercise Physiologist, Rehabilitation Nurse, Psychologist, as per Physiatrist's prescription. Both the comprehensive rehabilitation program and pain medications will continue to be managed by participant's Physiatrist, who will be blinded to patient's allocation. The researchers will be responsible for TPI and for data collection.
Sham Comparator: Placebo; 3 weekly sessions of subcutaneous saline injections. Participants will undergo 0.2mL subcutaneous saline injections superficial to the trigger points identified at initial assessment. The same superficial sites will be injected in all procedures.	Other: Comprehensive Rehabilitation program; Patients in both groups will undergo standard of care rehabilitation delivered by a Physiatrist, which may include Physical Therapy, Occupational Therapy, Exercise Physiologist, Rehabilitation Nurse, Psychologist, as per Physiatrist's prescription. Both the comprehensive rehabilitation program and pain medications will continue to be managed by participant's Physiatrist, who will be blinded to patient's allocation. The researchers will be responsible for TPI and for data collection.; Procedure: Subcutaneous saline injection; 0.2mL subcutaneous saline injections superficial to the muscles identified with active trigger points at the day of intervention (pectoralis major, serratus anterior, levator scapulae, latissimus dorsi, infraspinatus).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Visual Numeric Scale (VNS) for pain in 3 months	Mean difference of Pain between groups from baseline to 3 months(T3m), assessed by the Visual Numeric Scale (VNS, 0-10), in which higher scores represent higher pain intensity.	3 months
Trigger-points	Number of active trigger-points in the assessed muscles (latissimus dorsi, levator scapulae, trapezius superior, infraspinatus, pectoralis major, serratus anterior). Mean difference between groups.	1 month
Trigger-points	Number of active trigger-points in the assessed muscles (latissimus dorsi, levator scapulae, trapezius superior, infraspinatus, pectoralis major, serratus anterior). Mean difference between groups.	3 months
Pressure Pain Threshold (PPT)	Pressure Pain Threshold (PPT) at bilateral latissimus dorsi, levator scapulae, trapezius superior, infraspinatus, pectoralis major, serratus anterior. Difference from baseline	1 month
Pressure Pain Threshold	Pressure Pain Threshold (PPT) at bilateral latissimus dorsi, levator scapulae, trapezius superior, infraspinatus, pectoralis major, serratus anterior. Difference from baseline	3 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Visual Numeric Scale (VNS) for pain in 1 month	Mean difference of Pain between groups from baseline,assessed by the Visual Numeric Scale (VNS, 0-10), in which higher scores represent higher pain intensity.	1 month
Short-Form McGill Pain Questionnaire (SF-MPQ) - total score, sensorial and affective scale	Short-Form McGill Pain Questionnaire - total score, sensorial and affective scale. Mean difference between groups from baseline. Higher values represent higher pain intensity	1 month
Short-Form McGill Pain Questionnaire (SF-MPQ) - total score, sensorial and affective scale	Short-Form McGill Pain Questionnaire - total score, sensorial and affective scale. Mean difference between groups from baseline. Higher values represent higher pain intensity	3 months
Neuropathic Pain Symptom Inventory (NPSI)	Neuropathic Pain Symptom Inventory . Mean difference between groups from baseline. Higher values represent more symptoms of neuropathic pain.	1 month.
Neuropathic Pain Symptom Inventory (NPSI)	Neuropathic Pain Symptom Inventory . Mean difference between groups from baseline. Higher values represent more symptoms of neuropathic pain.	3 months
Disabilities of the Arm, Shoulder and Hand Questionnaire (DASH)	Disabilities of the Arm, Shoulder and Hand Questionnaire (DASH). Mean difference between groups from baseline. Higher values represent lower functionality.	1 month
Disabilities of the Arm, Shoulder and Hand Questionnaire (DASH)	Disabilities of the Arm, Shoulder and Hand Questionnaire (DASH). Mean difference between groups from baseline. Higher values represent lower functionality.	3 months
Shoulder range of motion (ROM)	Range of motion (ROM) of affected shoulder, for abduction and external rotation. Mean difference between groups from baseline.	1 month
Shoulder range of motion (ROM)	Range of motion (ROM) of affected shoulder, for abduction and external rotation. Mean difference between groups from baseline.	3 months
Percentage of patients with at least 30% improvement of pain as per VNS scores (VNS30%)	Percentage of patients with at least 30% improvement of pain as per VAS scores (VAS30%). Mean difference between groups.	1 month
Percentage of patients with at least 30% improvement of pain as per VNS scores (VNS30%)	Percentage of patients with at least 30% improvement of pain as per VAS scores (VAS30%). Mean difference between groups.	3 months
Percentage of patients with at least 50% improvement of pain as per VNS scores (VNS50%)	Percentage of patients with at least 50% improvement of pain as per VAS scores (VAS30%). Mean difference between groups.	1 month
Percentage of patients with at least 50% improvement of pain as per VNS scores (VNS50%)	Percentage of patients with at least 50% improvement of pain as per VAS scores (VAS30%). Mean difference between groups.	3 months
Adverse events	Number of participants with adverse events. Mean difference between groups.	1 month
Adverse events	Number of participants with adverse events. Mean difference between groups.	3 months
Pain medication	Use of pain medication. Classified as "Increased", "Decreased", "Stable" or "Non-applicable" . Mean difference between groups.	1 months
Pain medication	Use of pain medication. Classified as "Increased", "Decreased", "Stable" or "Non-applicable" . Mean difference between groups.	3 months

Collaborators and Investigators

• Sponsor: Instituto do Cancer do Estado de São Paulo
• Collaborators: Hospital de Câncer de Barretos
• Investigators: Study Director: Christina May Moran de Brito, MD, PhD, Instituto do Câncer do Estado de São Paulo

Publications and helpful links

General Publications

• Wisotzky E, Hanrahan N, Lione TP, Maltser S. Deconstructing Postmastectomy Syndrome: Implications for Physiatric Management. Phys Med Rehabil Clin N Am. 2017 Feb;28(1):153-169. doi: 10.1016/j.pmr.2016.09.003.

Study record dates

Study Major Dates

• Study Start (Actual): January 3, 2020
• Primary Completion (Estimated): November 30, 2023
• Study Completion (Estimated): February 15, 2024

Study Registration Dates

• First Submitted: January 29, 2020
• First Submitted That Met QC Criteria: February 11, 2020
• First Posted (Actual): February 12, 2020

Study Record Updates

• Last Update Posted (Actual): October 16, 2023
• Last Update Submitted That Met QC Criteria: October 13, 2023
• Last Verified: October 1, 2023

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Mental Disorders; Pathologic Processes; Nervous System Diseases; Disease; Musculoskeletal Diseases; Rheumatic Diseases; Muscular Diseases; Neuromuscular Diseases; Syndrome; Fibromyalgia; Somatoform Disorders; Myofascial Pain Syndromes
• Other Study ID Numbers: 1474/19

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