Abstract：
BACKGROUND: Spinal anesthesia (SA) is used in lumbar surgery, but initial adequate analgesia fails in some patients. In these cases, spinal redosing or conversion to general endotracheal anesthesia is required, both of which are detrimental to the patient experience and surgical workflow.
METHODS: We reviewed cases of lumbar surgery performed under SA from 2017-2021. We identified 12 cases of inadequate first dose and then selected 36 random patients as controls. We used a measurement tool to approximate the volume of the dural sac for each patient using T2-weighted sagittal magnetic resonance imaging sequences.
RESULTS: Patients who had an inadequate first dose of anesthesia had a significantly larger dural sac volume, 22.8 ± 7.9 cm3 in the inadequate dose group and 17.4 ± 4.7 cm3 in controls (P = 0.043). The inadequate dose group was significantly younger, 54.2 ± 8.8 years in failed first dose and 66.4 ± 11.9 years in controls (P = 0.001). The groups did not differ by surgical procedure (P = 0.238), level (P = 0.353), American Society of Anesthesia score (P = 0.546), or comorbidities.
CONCLUSIONS: We found that age, larger height, and dural sac volume are risk factors for an inadequate first dose of SA. The availability of spinal magnetic resonance imaging in patients undergoing spine surgery allows the preoperative measurement of their thecal sac size. In the future, these data may be used to personalize spinal anesthesia dosing on the basis of individual anatomic variables and potentially reduce the incidence of failed spinal anesthesia in spine surgery.
METHODS: We reviewed cases of lumbar surgery performed under SA from 2017-2021. We identified 12 cases of inadequate first dose and then selected 36 random patients as controls. We used a measurement tool to approximate the volume of the dural sac for each patient using T2-weighted sagittal magnetic resonance imaging sequences.
RESULTS: Patients who had an inadequate first dose of anesthesia had a significantly larger dural sac volume, 22.8 ± 7.9 cm3 in the inadequate dose group and 17.4 ± 4.7 cm3 in controls (P = 0.043). The inadequate dose group was significantly younger, 54.2 ± 8.8 years in failed first dose and 66.4 ± 11.9 years in controls (P = 0.001). The groups did not differ by surgical procedure (P = 0.238), level (P = 0.353), American Society of Anesthesia score (P = 0.546), or comorbidities.
CONCLUSIONS: We found that age, larger height, and dural sac volume are risk factors for an inadequate first dose of SA. The availability of spinal magnetic resonance imaging in patients undergoing spine surgery allows the preoperative measurement of their thecal sac size. In the future, these data may be used to personalize spinal anesthesia dosing on the basis of individual anatomic variables and potentially reduce the incidence of failed spinal anesthesia in spine surgery.
摘要：
背景：脊柱麻醉（SA）用于腰椎手术，但一些患者的初始镇痛失败。在这些情况下,脊髓再给药或转换为一般气管内麻醉是必需的，这两者都不利于患者体验和手术工作流程。
方法：我们回顾了2017-2021年在腰麻下进行的腰椎手术病例。我们确定了12例首次剂量不足的病例，然后随机选择36例患者作为对照。我们使用测量工具使用T2加权矢状MRI序列来近似每位患者的硬脑膜囊体积。
结果：第一次麻醉剂量不足的患者硬膜囊体积明显增大，剂量不足组22.8±7.9cm3，对照组为17.4±4.7cm3(p=0.043)。剂量不足组明显年轻，第一次给药失败54.2±8.8年，对照组为66.4±11.9年(p=0.001)。两组的手术方式没有差异（p=0.238），水平（p=0.353），ASA评分（p=0.546），或合并症。
结论：我们发现年龄，较大的高度,和硬脑膜囊体积是SA首次剂量不足的危险因素。在接受脊柱手术的患者中，脊柱MRI的可用性允许术前测量他们的鞘囊大小。在未来,这些数据可用于根据个体解剖变量个性化椎管内麻醉给药,并有可能降低脊柱手术中椎管内麻醉失败的发生率.
方法：我们回顾了2017-2021年在腰麻下进行的腰椎手术病例。我们确定了12例首次剂量不足的病例，然后随机选择36例患者作为对照。我们使用测量工具使用T2加权矢状MRI序列来近似每位患者的硬脑膜囊体积。
结果：第一次麻醉剂量不足的患者硬膜囊体积明显增大，剂量不足组22.8±7.9cm3，对照组为17.4±4.7cm3(p=0.043)。剂量不足组明显年轻，第一次给药失败54.2±8.8年，对照组为66.4±11.9年(p=0.001)。两组的手术方式没有差异（p=0.238），水平（p=0.353），ASA评分（p=0.546），或合并症。
结论：我们发现年龄，较大的高度,和硬脑膜囊体积是SA首次剂量不足的危险因素。在接受脊柱手术的患者中，脊柱MRI的可用性允许术前测量他们的鞘囊大小。在未来,这些数据可用于根据个体解剖变量个性化椎管内麻醉给药,并有可能降低脊柱手术中椎管内麻醉失败的发生率.
