The purpose of this randomized study is to examine the effect of a selective suprascapular nerve block on post operative pain after arthroscopic shoulder surgery. Half of the subjects will receive a active nerve block with Ropivacain. Half of the subjects will receive a placebo nerve block with saline.
Postoperative pain management after arthroscopic shoulder surgery traditionally includes opioids and/or an interscalene brachial plexus block(IBPB). Opioid consumption often leads to unpleasant side effects including nausea, vomitting and sedation. IBPB offers very efficient pain relief but includes the discomfort of a paralyzed arm. Furthermore this approach often also leads to unilateral paresis of the phrenic nerve causing reduced respiratory capacity. The latter offering discomfort and a potential risk in patients with lung diseases or heavy overweight. The suprascapular nerve is the most important nerve to the shoulder and a selective block of this nerve could offer a good pain relief without the mentioned side effects. In this randomized study the investigators wish to examine the pain relieving effect of a selective block of the suprascapular nerve after arthroscopic shoulder surgery. 40 patients are randomized to a block of this nerve with either active drug (Ropivacaine) or placebo (Saline). All patients will get a PCA (Patient Controlled Analgesia) pump for administration of i.v. morphine in doses based on age and weight. Patient are being monitored for 6 hours. The primary outcome is reduction in VAS at rest from baseline to 30 minutes after nerve block.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
QUADRUPLE
Enrollment
40
Ropivacaine injected perineural at the suprascapular nerve.
Saline injected perineural at the suprascapular nerve.
PCA (Patient controlled analgesia) pump with the following settings: Age \> 70 years or weight \< 60 kg: bolus dose 2,5 mg i.v. morphine, 15 minutes lockout Age \< 70 years and weight \> 60 kg: bolus dose 5 mg i.v. morphine, 15 minutes lockout Lockout time 15 minutes.
Nordsjællands Hospital
Hillerød, Denmark
Holbæk Sygehus
Holbæk, Denmark
Visual analogue scale (VAS) score at rest at T½
Change in VAS score at rest from baseline to 30 minutes after nerve block (T½).
Time frame: Baseline to 30 minutes
VAS score during maximum active shoulder abduction from T½ to T6
VAS scores measured at 7 timepoints (T½, T1, T2, T3, T4, T5, T6) during maximal active shoulder abduction and calculated as area under the curve (AUC).
Time frame: ½, 1, 2, 3, 4, 5, 6 hours
VAS score at rest from T½ to T6
VAS scores measured at 7 timepoints (T½, T1, T2, T3, T4, T5, T6) at rest and calculated as area under the curve (AUC).
Time frame: ½, 1, 2, 3, 4, 5, 6 hours
Morphine consumption.
The total amount of morphine administered via the intravenous PCA pump the first 6 hours after nerve block.
Time frame: 6 hours
Electromyography at T½
Change in activity of the infraspinatus muscle measured with surface electromyography from baseline to T½.
Time frame: Baseline to 30 minutes
Muscle strength at T½
Change in strength of the supraspinatus (abduction of the shoulder) and the infraspinatus muscle (external rotation of the shoulder) measured with a handheld dynamometer from baseline to T½.
Time frame: Baseline to 30 minutes
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