accounting for啥意思？

Moreover, when patients receive surgery for spinal stenosis, disc herniation, or pathology with compromise of the available space within the spinal canal, there is a risk of cauda equina syndrome or spinal cord compression with any additional space-occupying volume within vertebral canal (e.g., blood, abscess, injected fluid volume such as local anesthetic epidural bolus or infusion). Non-neurosurgical cases have been reported where neuraxial block injectate was considered to be responsible for the presentation of spinal cord ischemia, compression, and/or cauda equina syndrome [5]. Interestingly, combined spinal-epidural techniques were more often found to be the culprit of contributing to and/or masking neurologic symptoms from spine and nerve root compression, than either spinal or epidural alone. In this context, theoretically, spinal anesthesia may be lower risk for spinal cord compression in patients in pre- existing compressive pathology, as it involves only a low- volume injectate directly into the CSF. However, when spinal anesthesia is performed below the compressive lesion (i.e., stenosis or disc herniation), it may theoretically have less optimal spread to the areas above the lesion, resulting in block failure or even possible neural toxicity due to accumulation of local anesthesia below the level of stenosis. Some authors [5] recommend considering the safety of neuraxial anesthesia in patients with existing spine pathology, particularly with severe stenoses, compression, and pre-existing space-occupying lesions. They recommend considering that these patients may require multiple attempts for neuraxial or regional anesthesia, as well as keeping in mind the increased risk of failure, abnormal anatomy, and accounting for previous surgeries/interventions. One study showed that patients with spine pathology can experience more than two times the increased frequency of paresthesias when receiving intrathecal injections or catheter placement.

此外，当患者因椎管狭窄、椎间盘突出或椎管内可用空间受损而手术时，可能会因椎管内任何额外的占位（例如：血液、脓肿、局部麻醉剂硬膜外推注或输液等注射的液体量）而有马尾综合征或脊髓压迫的风险。非神经外科病例中曾报道认为椎管内阻滞注射液导致了脊髓缺血、压迫或马尾神经综合征^[5]。有趣的是，与单独使用脊麻或硬膜外麻醉相比，更常发现脊麻硬膜外联合麻醉技术是导致和掩盖脊髓和神经根受压引起的神经系统症状的罪魁祸首。这时，理论上脊麻可能会降低已有压迫病灶患者脊髓压迫的风险，因为它向脑脊液中只注射低体积药液。然而，当在压迫性病变（即狭窄或椎间盘突出症）下方进行脊麻时，理论上它可能无法最佳地扩散到病变上方的区域，导致阻滞失败，甚至可能由于局部麻药的积聚在狭窄水平以下而导致神经毒性。一些作者^[5]建议警惕在脊柱病变患者中椎管内麻醉的安全性，尤其是伴有严重狭窄、压迫和既存存占位性病变的患者

他们建议提前考虑到这些患者可能需要多次尝试进行椎管内或区域麻醉，并牢记失败风险增加、解剖异常以及预防性手术/干预。一项研究表明，在鞘内注射或导管置入时，脊柱病变患者出现感觉异常的频率可能增加2倍以上。