Suprascapular Nerve Block Versus Intraarticular Steroid Injection in Hemiplegic Shoulder Pain

Suprascapular nerve block versus(vs) intra-articular steroid injection in the management of hemiplegic shoulder pain (HSP): a randomised, double blinded, controlled trial

BACKGROUND Hemiplegic shoulder pain (HSP) is a common complication of stroke. It can happen as early as one week post stroke with a frequency as high as 72%. HSP can result in significant disability as pain and limited shoulder range of motion (ROM) decrease hand function, reduce participation in rehabilitation activity and delay functional recovery of the patients. Management of HSP focused on reducing pain and improving shoulder ROM. Minimally invasive treatment of HSP with intra-articular shoulder steroid (IAS) injection and supra-scapular nerve block (SSNB) have gained interest.

OBJECTIVES

Primary objective:

1. To assess the analgesic effect of SSNB vs IAS in HSP among Malaysian stroke population.

   Secondary objectives:
2. To assess the improvement of passive ROM post SSNB versus IAS in HSP.
3. To assess for improvement of functional outcome post SSNB versus IAS in HSP.

METHOD

A prospective, double blinded interventional study will be conducted in the Rehabilitation Medicine Clinic, University of Malaya Medical Centre for a duration of 1 year. Eligible subjects will be enrolled from all referrals of hemiplegic shoulder pain (HSP), following computer-generated randomization they will be allocated to either supra-scapular nerve block (SSNB) (intervention) or intra-articular shoulder steroid injection (IAS) (control) groups. The subjects and assessors are blinded to the intervention received, which will be performed by an experienced interventionist, not participating in randomization or data collection and analysis. Demographics of participants time since stroke, etiology, presence of spasticity, Numerical Rating Score (NRS) pain score at maximal passive ROM, maximum passive ROM of shoulder flexion, abduction, internal and external rotation as well as SDQ and SPADI will recorded prior to injection, 1 hour, 1 month and 3 months post injection. Mann-Whitney U tests and Chi-Square test of association will be used as appropriate to compare groups at baseline. Shoulder ROM and NRS pre and post intervention will be analysed using paired t-test and ANOVA. Functional outcome of SDQ and SPADI pre and post intervention will be analysed using paired t-test as well.

1. INTRODUCTION

1.1 Research Area

Hemiplegic shoulder pain (HSP) is a common clinical consequence of stroke with reported frequency as high as 72% (1). Onset of HSP is more common at 2-3 months post stroke(2). HSP can reduce participation in rehabilitation activities and reduce quality of life(3). The etiology of HSP includes neurological and mechanical factors, although mechanical factors are more common. Mechanical factors include structural injury from glenohumeral subluxation, or rotator cuff pathology (3). In hemiplegic patients, the nociceptive pain ratio was higher at 86.7% compared to neuropathic pain ratio; 13.3% (4). Management of HSP focused on reducing pain and improving shoulder ROM. Minimally invasive treatment of HSP with intra-articular steroid (IAS) injection and supra-scapular nerve block (SSNB) have lately gained interest. However, 2 studies done so far showed that while both SSNB and IAS showed significant differences in reducing shoulder pain and improving ROM with time, there was no significant difference of these injection method in comparison to conventional treatment. None of the studies done to date documents functional outcome of patients post injection with IAS or SSNB. The main purpose of this study is to assess the analgesic effect of SSNB vs IAS in HSP among Malaysian stroke population as well as to look at the improvement of shoulder ROM and functional outcome measure.

1.2 Research Questions

Does supra-scapular nerve block (SSNB) provide better pain relief, passive range of motion (PROM) and functional outcome compared to intraarticular steroid (IAS) injection in hemiplegic shoulder pain?

1.3 Significance of this study

SSNB is an effective and safe method for pain relief and increases ROM in many group of patients who had shoulder pain such as non specific shoulder pain (5),chronic shoulder pain(6) and rotator cuff tendinitis(7). SSNB can be performed using ultrasound guidance where injection of Bupivacaine is made at posterior shoulder towards suprascapular notch. Side effects include; worsening pain, soreness, bruising, nerve damage, allergic reaction.

IAS on the other hand is performed by injecting 40 mg of Triamcinolone Acetonide along with 2 ml of Lidocaine 1% into glenohumeral articular space (8). Systematic reviews of treatments for sub acromial pain favor IAS over the following options: ergonomic changes, NSAID, acupuncture, ROM and strengthening exercises, ultrasound, ice, heat, and physical therapy (9,10). Side effects include; post injection flare, disturbance of menstrual pattern, facial flushing, subcutaneous tissue atrophy, skin depigmentation, infection, and tendon rupture (13).

2 studies done so far that compare IAS vs SSNB head to head; Yasar et al,2011 and Jeon et al, 2014 only followed up the patients up to 1/12 only. Besides, there was no functional outcome measure done (11,12). Other study done with longer follow up times such as Adey-Wakeling et al, 2013 SSNB vs s/c saline (Placebo) consistently demonstrated superior, statistically significant pain reduction compared with s/c saline (placebo) even at 12/52 post injection (13).

Another randomized controlled trial (RCT) by Rah et al,2012 in comparing IAS vs subacromial lignocaine (placebo) showed significant improvement of visual analogue scale (VAS)-day/night, ROM as well as SDQ, in the treatment group even at 8/52(14). Besides, stroke is extremely common in Malaysia and is the 3rd leading cause of death in our country. Stroke patients in Malaysia is generally younger with mean age of stroke onset between 54.5 and 62.6 (15).

HSP will affect stroke recovery as the pain interfere with rehabilitation and has a potential to worsen the disability in hemiplegic patients and negatively impaired quality of life (QOL) (16).

2.0 Methodology

2.1 Study Design

This study design is prospective, double blinded interventional study. In this study, patient will be blinded from the interventions they are receiving; intraarticular steroid injection or supra-scapular nerve block. Investigator that will be assessor will also be blinded from knowing the interventions that patients received.

2.1.1 Enrollment Patients referred to SMART Clinic for hemiplegic shoulder pain will be examined and recruited. Patients who did not fulfill the inclusion and exclusion criteria will be excluded.

Numerical rating score (NRS) pain score at maximum passive ROM of shoulder flexion, abduction, internal and external rotation, Maximum passive ROM of shoulder flexion, abduction, internal and external rotation, Shoulder Pain and Disability Index (SPADI) and Shoulder Disability Questionnaire (SDQ) will be measured prior to intervention.

2.1.2 Allocation The patients recruited will then be randomly allocated using a randomization computer program into 2 separate groups; Suprascapular nerve block(SSNB) group and Intraarticular steroid(IAS) group. The assessor and patients are blinded to the type of intervention the patient is receiving. The injector who is a skilled interventionist will not be blinded.

2.1.3 Intervention Suprascapular nerve block (SSNB) and Intraaticular steoid(IAS) injection will be performed by skilled interventionist.

2.1.4 Evaluations Numerical rating score (NRS) pain score at maximum passive ROM of shoulder flexion, abduction, internal and external rotation and maximum passive ROM of shoulder flexion, abduction, internal and external rotation will be assessed and recorded at 1 hour, 1 month and 3 months after intervention. Shoulder Pain and Disability Index (SPADI) and Shoulder Disability Questionnaire (SDQ) will be measured at 1 month and 3 months post intervention.

2.2 Setting

• Rehabilitation Clinic, University of Malaya Medical Center (UMMC)

2.3 Sample Size

A power analysis program G\* Power was used to calculate the sample size. The effect size of study by Jeon et al is 0.3. With the power of study set at 0.8 and alpha set at 0.05, the sample size for this study based on G\* Power sample size calculator is set at 64; 32 each arm. However, to allow for 25% attrition rate, the sample size is set at 86; 43 each arm.

3.0 Data Collection Methods

Primary Outcome :

* Numerical rating score (NRS) pain score at maximum passive ROM of shoulder flexion, abduction, internal and external rotation
* To be collected at baseline, 1 hour, 1 month and 3 months post injection

Secondary outcome :

* Maximum passive ROM of shoulder flexion, abduction, internal and external rotation
* Measured at baseline, 1 hour, 1 month and 3 months post injection.
* Shoulder Pain and Disability Index (SPADI) and Shoulder Disability Questionnaire (SDQ)
* Measured at baseline, 1 month and 3 months post intervention.
* Using face to face interview

3.1 Data Analysis

Data from this study will be analysed using Statistical Package for Social Science (SPSS) software.

Demographics of 2 groups will be analyzed using Mann-Whitney U tests and Chi-Square test of association.

Primary objective:

Pain reduction:

Pre-post intervention intra-group; post-intervention inter-group: paired t-test

Secondary objectives:

ROM improvement: pre-post intragroup; post-intervention inter-group: paired t-test and analysis of variance (ANOVA)

Functional improvement of SDQ and SPADI: pre-post intra-group; post-intervention inter-group: paired t-test

4.0 Strength and Limitation

Strength

* Secondary outcomes include functional outcomes such as SPADI Score and SDQ
* Longer follow up period at 3 months compared to study by Jeon et al and Yasar et al at 1 month
* Bigger sample size Limitation
* Single center study
* Risk of patient loss to follow-up
* Recruitment will be a challenge

Eligibility Criteria:
Inclusion Criteria:

* Brain lesion recognized by CT Brain scan or MRI brain
* Hemiplegic shoulder pain of at least 2 weeks in duration
* Failed standard treatment with oral medications and physical modalities
* Age 20-70 years old
* Pain score of at least numerical rating scale (NRS) 3/10 at movement
* Mini Mental State Examination(MMSE) at least 24/30

Exclusion Criteria:

* Neuropathic pain
* Severe aphasia affecting communication
* Previous trauma history to affected shoulder and preexisting shoulder pain/pathology
* Previous shoulder injection within the past 3 months