Cervical Cord Compression and Hypertension

Study Overview
=================
Brief Summary
-----------------
Myelopathy from cervical cord compression may induce hypertension and sympathetic hyperactivity. Anesthesia may suppress sympathetic activity and lead to hypotension that require vasopressor treatment. We aim to elucidate the causative factors for severe hypotension during anesthesia by prospective observational study.

Detailed Description
-----------------
It had been reported the cervical spondylotic myelopathy may lead to the development of hypertension. Decompression surgeries ameliorated neurological symptoms as well as the blood pressure. The cause may be the abnormality of autonomic dysfunction developed after myelopathy. However, the evidence was weak. We have noticed a tendency of hypotension during anesthesia in patients undergroing cervical spine surgeries, especially in surgeries of long levels and hypertensive patients. Thus we postulate the autonomic activity is abnormal in patients with cervical myelopathy. Sympathetic hyperactivity developed in order to maintain adequate perfusion to the cervical cord. When patients are under anesthesia, the sympathetic tone is suppressed, thus leading to severe hypotension that require the treatment of inotropic treatment. Heart rate variability (HRV) is a good index of autonomic activity. Thus we plan to Therefore we will measure the HRV (analysis of ECG) and baroreflex activity (analysis of arterial line during the anesthesia) in patients undergoing cervical spine surgeries for decompression of cord compression perioperatively. The primary end-point is the comparison of severity of cord compression between normotensive and hypertensive patients with cervical myelopathy. The secondary end-point is to compare blood pressure and HRV pre- and postoperatively. The third end-point is to elucidate the causative factors for severe hypotension during anesthesia.

Official Title
-----------------
Effect of Cervical Compressive Myelopathy on the Autonomic Nervous System and Clinical Implication

Conditions
-----------------
Hypertension

Intervention / Treatment
-----------------
* Procedure: Decompression surgery


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: cervical spine surgery for cord compression Exclusion Criteria: spinal cord injury ASA class >3 chronic kidney disease congestive heart failure BMI>30 atrial fibrillation/ flutter obstructive sleep apnea

Ages Eligible for Study
-----------------
Minimum Age: 20 Years
Maximum Age: 70 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| normotension<br>patients without diagnosis or treatment for hypertension | Procedure: Decompression surgery<br>* The surgeries aim to relieve the myelopathy from cord compression<br>* Other names: cervical spine decompression surgery;|
| hypertension<br>patients with diagnosis or treatment for hypertension | Procedure: Decompression surgery<br>* The surgeries aim to relieve the myelopathy from cord compression<br>* Other names: cervical spine decompression surgery;|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| change of blood pressure | noninvasive blood pressure | one day before surgery, during surgery, 3 months after surgery, 6 months after surgery | 
| change of hear rate variability | from analysis of ECG | one day before surgery, during surgery, 3 months after surgery, 6 months after surgery | 
| baroreflex activity | from analysis of arterial blood pressure waveform | during surgery (anesthesia) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| change of Japanese Orthopaedic Association Scores | 17 points neurological assessment for cervical spine pathology (from 0 17; 0 denotes worst neurological condition, 17 denotes intact ) | one day before surgery, 3 months after surgery, 6 months after surgery | 
| change of the Nurick scores | 6 grades neurological assessment for cervical spine pathology (Grade 0: no root or cord symptoms; 1, signs or symptoms of root involvement only; 2, signs of spinal cord involvement (normal gait); 3, mild gait abnormality (does not prevent employment); 4, gait abnormality prevents employment; 5, only able to walk with assistance; 6, chair bound or bedridden) | one day before surgery, 3 months after surgery, 6 months after surgery | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
heart rate variability, cervical myelopathy, blood pressure, decompression