Neuropathy of the Suprascapular Nerve Before and After Reconstruction of the Cuff

Study Overview
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Brief Summary
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The suprascapular nerve innervates the musculi supra- and infraspinatus, which, as part of the rotator cuff, allow lifting and external rotation in the shoulder joint. Damage to this nerve can lead to pain and functional deficit. Causes of injury are compression by bony / ligamentous anomalies, fracture sequelae and traction damage. In the literature, a (often subclinical) traction damage is increasingly claimed by a muscle retraction after rupture of the supra- and / or infraspinatus tendon as a cause of pain and functional disturbances. The retraction of the ruptured tendon-muscular unit is said to lead to traction damage of the nerve, which can be demonstrated by pathological EMG derivations. By repositioning the tendon to its outbreak site, the nerve is occasionally overstretched, so that individual authors propagate a routine nerve decompression as prophylaxis. In individual cases, a previously pathologic EMG result could be improved after reconstitution of an rotator cuff rupture. However, prospective studies are not available. It is not known how often a nerve damage is present before a rotator cuff operation and it is not known how often the tendon repair leads to nerve damage or recovery of damage. It is not known whether the surgical nerve decompression is associated with reduced postoperative pain and what a profit or what risks bring about a routine decompression of the nerve to the patient. To answer this question, this prospective randomized study is to be carried out.

Detailed Description
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On the basis of preoperative electromyography (EMG) and electroneurography (ENG), the investigators would like to determine the frequency of suprascapular neuropathy in ruptures of supra- and / or infraspinatus tendons and the risk factors for their presence. In a ruptured rotator cuff, the muscle is partly retracted so much that the innervating nerve (suprascapular nerve) is stretched and has pathological neurological findings. The Investigators now want to analyze how the arthroscopic reconstruction of the nasal suprascapular nerve affects the pre-operative neuropathy. Does the pre-existing nerve recover by decompression (liberation) from surrounding / entangling tissue or does decompression have no influence on measurable neurology? Other patients with rotator cuff ruptures have normal neurological findings preoperatively despite severe retraction of the muscular / tendon unit. In these cases, the investigators are interested in whether the mobilization and reconstruction of the torn muscle / tendon unit leads to a neurologically measurable elongation of the nerve. This nerve stretching is a possible explanation for protracted postoperative pain. With the postoperative electrophysiological measurements we can quantify this nerve change. The comparison between preoperative and postoperative neurology findings allows confirmation or refutation of our hypothesis.

Official Title
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Neuropathy of the Suprascapular Nerve Before and After Reconstruction of the Cuff

Conditions
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Cuff Rotator Full Thickness Tear, Cuff Rotator Syndrome

Intervention / Treatment
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* Procedure: Release or no release of the suprascapular nerve


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Informed Consent MRI diagnosis of partial or full thickness rotator cuff tear Exclusion Criteria: Previous surgery Fatty muscle infiltration Goutallier stages III and IV Diabetes mellitus pregnancy unwillingness or contraindications for Magnetic resonance imaging unwillingness or contraindications to electrophysiological assessment substance abuse

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 99 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: no release<br>no release of the suprascapular nerve during arthroscopic repair of a rotator cuff tendon repair | Procedure: Release or no release of the suprascapular nerve<br> <br> |
| Experimental: release<br>arthroscopic release of the suprascapular nerve according to the established, standard technique during arthroscopic repair of a rotator cuff tendon repair | Procedure: Release or no release of the suprascapular nerve<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| electromyographic assessment of suprascapular nerve function | sharp waves, complex repetitive discharges and fasciculations in supra- and infraspinatus muscles. Presence or absence | preoperatively, change from preoperatively to 3 months and change from 3 to 12 months | 
| electromyographic assessment of suprascapular nerve function | motor latency to supra- and infraspinatus muscles milliseconds | preoperatively, change from preoperatively to 3 months and change from 3 to 12 months | 
| electromyographic assessment of suprascapular nerve function | conduction velocity (m/sec) | preoperatively, change from preoperatively to 3 months and change from 3 to 12 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Maximal daily pain on visual analog scale | Measurement of pain using a visual analog scale 100 points maximal imaginable pain; 0 no pain | preoperatively and change from preoperatively to 3 months and change from 3 to 12 months | 
| Active range of motion | Measurement of active elevation, abduction external and internal rotation in degrees measured with a handheld goniometer. | preoperatively and change from preoperatively to 3 months and change from 3 to 12 months | 
| Strength | Isometric measurement of strength of shoulder abduction in pounds (1 pound represents 1 point in the scoring system)using a validated dynamometer | preoperatively and change from preoperatively to 3 months and change from 3 to 12 months |