The Effect of Blood Pressure Value on Intraoperative Imaging in Biportal Endoscopic Spine Surgery

In unilateral biportal endoscopic (UBE) decompression surgery, image quality reduces potential risks in the surgical field and allows the surgical procedure to be performed in a shorter time. This study aimed to investigate the relationship between visualization and blood pressure during surgery and to determine the optimal blood pressure to maintain good visualization during surgery.

A senior surgeon and an assistant surgeon independently evaluated intraoperative visualization during UBE entry, laminotomy, and foraminotomy. They assessed image quality based on blood pressure readings and each other on a scale of 1 to 4. (Grade 4: clear image; Grade 3: slight bleeding but operable; Grade 2: poor image clarity requiring hemostasis, with no water pressure augmentation or blood pressure therapy needed; Grade 1: unclear image due to significant bleeding, leading to the termination of surgery). During UBE, blood pressure was measured with the cuff on the arm 3 times at 2-minute intervals during the surgical grades, and the patient's systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) were recorded.

At the UBE entry grade, the cut-off value for SBP was 106.34 and 67.5 for DBP and 83.33 for MAP. In the laminectomy grade, the cut-off value for SBP was 93.83, the cut-off value for DBP was 58.5, and the cut-off value for MAP was 72.33. At the foraminotomy grade, the cut-off value for SBP was 89.17, 55.0 for DBP, and 70.67 for MAP.

Image clarity and patient blood pressure are inter-related during the UBE grades. Surgery keeping SBP below 106 mmHg so as not to pose a risk to the patient provides good image clarity.