Background: Modified thoracoabdominal nerves block through perichondrial approach (M-TAPA) was first described as a peripheral nerve block by Tulgar in 2019. This technique provides an analgesic effective range from Th7–11 with a single puncture per side. Although the efficacy and effective duration of M-TAPA have been reported, further examination is required. Therefore, this study aimed to evaluate the analgesic range and effective duration of M-TAPA in open gynecologic surgery. Methods: Following approval, 10 adult female patients scheduled for open radical hysterectomy via a vertical incision or laparotomy using a midline incision from under the xiphoid process to the symphysis pubis were enrolled. The primary outcome was the number of anesthetized dermatomes at 2 and 24 h postoperatively. Secondary outcomes included numerical rating scale scores and the total amount of fentanyl used. Cadaveric evaluation was performed to assess the spread of the dye. Results: The median numbers (interquartile range) of anesthetized dermatomes at 2 and 24 h postoperatively were 6 (5–7) and 6.5 (5–7) in the anterior cutaneous branch area and 5 (4–7) and 7 (5–7) in the lateral cutaneous branch area, respectively. There was an 85% chance of simultaneously acquiring analgesia in areas innervated by Th8–11, including complete block in areas innervated by the anterior cutaneous branches of Th9–10. Cadaveric evaluation showed the spread of the dye in Th8–11. Conclusions: M-TAPA may have analgesic effects in the areas supplied by the anterior cutaneous branches of Th8–11. Trail registration: IRB approval (No.2700; registered on July 10, 2020) and registration (UMIN Clinical Trials Registry: UMIN000041137; registered on July 17, 2020).

Purpose: Robot-assisted laparoscopic radical prostatectomy (RARP) requires a steep head-down tilt and pneumoperitoneum, which may cause an increase in cerebral blood volume (CBV). With a new near-infrared time-resolved spectroscopy device, the tNIRS-1, we can measure the absolute value of the cerebral hemoglobin concentration and hence calculate CBV and cerebral oxygen saturation (rSO ₂ ). Using this device, we evaluated the time course of CBV during surgery and also evaluated the changes in rSO ₂ simultaneously. Materials and Methods: We performed a prospective observational study of 21 patients scheduled for RARP. We evaluated CBV and rSO ₂ by using the tNIRS-1 at 10 time points during surgery. Results: The CBV was 2.92 ± 0.38 mL ·100 g ⁻¹ after the end of anesthetic preparation. It significantly increased to 3.05 ± 0.44 mL ·100 g ⁻¹ after the head-down tilt and was around 3.1 mL ·100 g ⁻¹ until 120 minutes after the head-down tilt. However, just before the return to the horizontal position, it decreased to 2.93 ± 0.46 mL ·100 g ⁻¹ and then decreased more after the return to the horizontal position. Changes in rSO ₂ over time were within only 3%, and no significant differences from the control value were observed. Conclusions: The increase in CBV was <10% despite the steep head-down tilt and pneumoperitoneum, and it was compensated for at around the end of surgery. Clinically significant changes in rSO ₂ were not observed during the surgery.