Detection and Prevention of Nerve Injury in Shoulder Arthroplasty Surgery

Study Overview
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Brief Summary
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Up to 5% of total shoulder arthroplasty patients experience transient or permanent nerve injury during surgery. In this study, we will monitor the nerve transmission of the patients' arm to detect whether the nerve is functioning normally. This techniques is called somatosensory evoked potential (SSEP) monitoring. In this study, we will assess whether SSEP monitoring could detect nerve abnormalities, alerts the surgical team enabling optimize their surgical intervention and prevent surgical related nerve injury.

Detailed Description
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Perioperative PNI is a well-recognized but seriously under-investigated complication of general anesthesia. Arguably, such nerve injury may be viewed as being as devastating as spinal cord and cerebral injury, as the resultant functional disabilities may be very comparable.(1) Many such nerve injured patients require prolonged recovery and rehabilitation, while some result in long-term disability and/or litigation due to motor deficits and chronic pain.(2-5) In ASA Closed Claims Analysis PNI was the second most common cause of claims other than death.(6, 7) However, little progress has been made in the past three decades in developing a reliable intraoperative monitoring technique for early detection and prevention. SSEP monitoring is a potential option for preventing PNI. Abnormal SSEP is widely used as a surrogate outcome for PNI in research studies (8-11). Additionally, previous studies (12-17) investigating the use of SSEP for spinal cord or cerebral injury during neurosurgical procedures have incidentally found high incidences of abnormal SSEP (4-7%) due to mal-positioning that was corrected with repositioning; this suggested SSEP could be used to detect intraoperative PNI and that prompt intervention can reverse PNI. However, there have been no further prospective studies to evaluate the diagnostic value of SSEP, or its outcome benefit. This is largely because conventional SSEP is a bulky, expensive and labor-intensive monitoring modality, requiring a technologist for operation and interpretation.(18) Because of these budgetary and logistical limitations, as well as the relative lack of clinical evidence, SSEP is not performed routinely in most surgical centres solely for the purpose of PNI detection. The recent introduction of the Evoked Potential Assessment Device (EPAD®, SafeOp Surgical, Hunt Valley, MD) may be able to overcome these practical barriers. It is a novel, simplified, automated SSEP monitoring device (FDA approved). The key features of EPAD® are its compactness, ease of connectivity via Bluetooth, and its use of surface adhesive electrodes that remove the potential for needle-stick injuries. This device also incorporates an automated progressive signal optimization algorithm, several newly developed artifact rejection and electrocautery suppression technologies as well as an auto-interpretation diagnostic system. It eliminates the need for a designated technician and permits simplified and direct interpretation of the SSEP data for clinicians in the operating room. This device also enables display and storage of raw SSEP data permitting post hoc area-under-curve analysis. (Fig. 3) We have previously evaluated the clinical utility of this automated SSEP device in 33 cardiac surgical patients (19). This pilot study found that automated SSEP monitoring can be performed readily in a busy cardiac operating room. The raw signal quality is reliable and comparable to the conventional SSEP machine. These results indicate that this device is able to eliminate the practical challenges of performing SSEP monitoring and confirmed its feasibility for routine use.(REB# 104826) Surgical-related nerve injury during TSA is one of the highest risk subspecialties leading to postoperative upper limb peripheral neuropathy with reported incidences of 1-4% (20-22). A previous cohort study10, using motor evoked potential and EMG to evaluate the nerve injury during TSA, reported an exceedingly high incidence of intraoperative alerts (56.7% of patients). Importantly, 76.7% (23 of 30) of nerve alerts were reversed with repositioning of the patients' arm and removal of the retractor. Another cohort study11 in shoulder rotator cuff repair reported an even higher incidence of nerve alert (76.5%). Both studies were received Neer research awards from the Orthopedic Society, however neither study has informed the outcome benefit nor has assessed the relationship between cumulative injury, baseline nerve reserve and postoperative neuropathy. Accordingly, we propose to perform single blinded, superiority, parallel design, prospective randomized controlled study to assess the efficacy of the automated SSEP device in preventing PNI during TSA and explore the dose-response relationship of PNI.

Official Title
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Detection and Prevention of Perioperative Nerve Injury Using Automated Somatosensory Evoked Potential Monitoring in Shoulder Arthroplasty Surgery

Conditions
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Neuropathy, Nerve Injury

Intervention / Treatment
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* Device: Automated Somatosensory Evoked Potential device (EPAD@)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adult elective patients undergoing total shoulder arthroplasty surgery using general anesthesia Exclusion Criteria: Patients unable to perform complete neurological examination Patients who refuse to participate Unable to obtain informed consent. Patients who are contraindicated for (or unable to perform) SSEP monitoring Patients who have known pre-existing peripheral neuropathy or brachial plexus injury Patients who are contraindicated to brachial plexus block

Ages Eligible for Study
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Minimum Age: 18 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: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: 1:1 parallel, superiority study
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Automated SSEP Monitored Group<br>SSEP monitored group: When a nerve alert is signaled by the automated SSEP device, the surgeon will be informed with the aim to reverse the signal changes. The possible surgical interventions include repositioning the operative arm into a more neutral position, avoidance of excessive traction, removal of retractors, and using a smaller implant to avoid over-correction/traction. The actual intervention will depend on the possible mechanism of nerve injury and treated accordingly. | Device: Automated Somatosensory Evoked Potential device (EPAD@)<br>* After commencement of general anesthesia and during patient positioning, stimulating sensors will be applied to patient wrists and a recording sensor is applied at base of neck posteriorly (at C5 level), forehead and the bilateral wrists. The monitoring will be continued throughout the surgery.<br>|
| No Intervention: Standard Group<br>The automated SSEP device will be connected and will be blinded to the surgeon. The screens of the automated SSEP device will be covered by an opaque plastic bag and the alarms will be turned off. No intervention is planned for this group. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cumulative duration of abnormal SSEP changes | The cumulative duration (min) of abnormal SSEP changes in the operative arm. | duration of surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| New-onset of peripheral neuropathy | New-onset peripheral neuropathy of the operative arm at postoperative 6 weeks. A thorough neurologic examination will be performed by an independent assessor before (after brachial plexus catheter inserted), and after the surgery (6 weeks). Any new neurological deficit at postoperative 6 weeks that identified by the independent outcomes assessor will be defined as a positive case. | 2 weeks, 6 weeks and 3 months | 
| American shoulder and elbow surgeons standardized shoulder assessment form | ASES score is a 100 point scale that consists of two dimensions; pain and daily activity. The pain scale is worth 50 points and the daily activity is worth 50 points. 100 points describes being pain- free and able to complete daily activity with no issues while a score of 0 describes extreme pain and unable to complete daily activities. | 2 weeks, 6 weeks and 3 months | 
| Quality of life measure | The EQ-5D-5L score consists of two components: a descriptive component to assess five dimensions of quality of life and an EQ visual analogue scale (VAS). The EQ-5D health state index is a single summary index, ranging from 0 to 1 (where 0 denotes death and 1 denotes full health/function), that is weighted to the country/region to describe the five dimensions of EQ-5D. | 2 weeks, 6 weeks and 3 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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nerve monitoring, automated somatosensory evoked potential, nerve injury