Department of Anesthesiology, Sindhuli Hospital, Sindhuli, Nepal.
Department of Anesthesiology and Intensive Care, National Academy of Medical Sciences, Bir Hospital, Kathmandu, Nepal.
Kathmandu Univ Med J (KUMJ). 2023 Jul-Sep;21(83):260-264.
Background Subarachnoid block is one of the commonly used techniques of regional anesthesia and accurate placement of spinal needle is crucial. A conventional spinal needle may be too long for a lean patient or too short in obese patients leading to multiple attempts, inadvertent nerve injuries and patient discomfort. So a pre-procedural estimation of the skin to subarachnoid space depth may be beneficial. Objective To estimate the skin to subarachnoid space depth using ultrasound and correlate it with the length of spinal needle to be inserted during subarachnoid block. Method This was a prospective, observational study conducted at Bir Hospital, Kathmandu in patients undergoing elective surgeries under subarachnoid block. A pre-procedural ultrasound of lumbo-sacral spine using 2-5 Hz curvilinear probe was done to measure skin to subarachnoid space depth (SSD) at the level of L3-L4 interspace. Then under all aseptic precautions, subarachnoid block was performed and the length of spinal needle outside the skin was measured and that length was subtracted from the standard length of needle to get the inserted length of spinal needle. These two measurements were compared. Result In the fifty patients included in the study, ultrasound estimated skin to subarachnoid space depth was found to be 4.24 ± 0.48 cm and the inserted length of spinal needle was 4.24 ± 0.46 cm. A significant correlation r=0.96 (p < 0.05) was found between the two measurements in the study population. Conclusion Ultrasound estimated skin to subarachnoid depth in the study population was found to be 4.24 ± 0.48 cm which correlated with the inserted length of spinal needle. So, use of ultrasound can be very helpful in performing subarachnoid block.
背景 蛛网膜下腔阻滞是区域麻醉中常用的技术之一，准确放置脊髓针至关重要。对于瘦患者，传统的脊髓针可能太长，而对于肥胖患者，传统的脊髓针可能太短，这会导致多次尝试、无意中的神经损伤和患者不适。因此，术前估计皮肤到蛛网膜下腔的深度可能会有所帮助。目的 使用超声估计皮肤到蛛网膜下腔的深度，并将其与蛛网膜下腔阻滞时要插入的脊髓针的长度相关联。方法 这是一项在尼泊尔加德满都比尔医院进行的前瞻性观察性研究，纳入了接受蛛网膜下腔阻滞下择期手术的患者。在术前使用 2-5 Hz 曲线探头对腰骶脊柱进行超声检查，以测量 L3-L4 椎间的皮肤到蛛网膜下腔的深度（SSD）。然后，在所有无菌预防措施下进行蛛网膜下腔阻滞，并测量脊髓针在皮肤外的长度，从标准针长中减去该长度，以获得插入的脊髓针的长度。比较这两个测量值。结果 在纳入的 50 例患者中，超声估计的皮肤到蛛网膜下腔的深度为 4.24 ± 0.48 cm，插入的脊髓针的长度为 4.24 ± 0.46 cm。研究人群中发现这两个测量值之间存在显著相关性 r=0.96（p < 0.05）。结论 在研究人群中，超声估计的皮肤到蛛网膜下腔的深度为 4.24 ± 0.48 cm，与插入的脊髓针的长度相关。因此，超声的使用在执行蛛网膜下腔阻滞时非常有帮助。
