Brau Salvador A, Spoonamore Mark J, Snyder Lance, Gilbert Constance, Rhonda Georgia, Williams Lytton A, Watkins Robert G
Department of Surgery, Keck School of Medicine, University of Southern California, Los Angeles, CA 90071, USA.
Spine J. 2003 Sep-Oct;3(5):351-5. doi: 10.1016/s1529-9430(03)00067-6.
There are no studies in the literature that correlate compression of the iliac vessels resulting in obstruction of blood flow with changes in nerve monitoring parameters during anterior lumbar surgery.
To determine whether there is significant compression of the iliac vessels that can cause temporary nerve root ischemia or limb ischemia that could be responsible for loss of somatosensory evoked potentials (SSEP) while retractors are in place for exposure during anterior lumbar interbody fusion (ALIF).
Patients coming to the operating room for ALIF from levels L2-L3 to L5-S1 would be studied for nerve monitoring changes during the procedure with particular attention to the intervals just before placement of a retractor, while the retractor was in place and immediately after removal of the retractor.
Forty-five consecutive patients were studied for changes in SSEP and oxygen saturation (SaO(2)) while undergoing ALIF.
Patients were considered to have lost saturation if the SaO(2) decreased to below 90%. Patients were considered to have abnormal SSEP with any increase in latency and decrease in amplitude.
SSEP and SaO(2) were monitored continuously and simultaneously before exposure of the disc spaces, during exposure with retractors in place and after removal of the retractors.
Thirteen of 23 patients with exposure at L4-L5 had both loss of SSEP signals and loss of SaO(2) with exposure. All 13 patients had return to normal saturation and recovery of the SSEP signals within 15 minutes of removal of the retractors. Both of these are significant correlations (p<.001).
This study showed that the majority (57%) of patients undergoing ALIF at the L4-L5 level are subject to compression of the left iliac vessels enough to cause desaturation distally as measured by pulse oxymetry. This vascular compromise, as well as the return to normal saturation, correlates with changes noted in SSEP soon after both deployment and removal of the retractors used for exposure. The mechanism appears to be a transient ischemic response. Failure of the SSEP signals to recover may be diagnostic of left iliac artery thrombosis.
文献中尚无关于腰椎前路手术期间，髂血管受压导致血流梗阻与神经监测参数变化之间相关性的研究。
确定在腰椎前路椎间融合术（ALIF）中使用牵开器暴露手术部位时，髂血管是否存在显著受压情况，这种受压是否会导致暂时性神经根缺血或肢体缺血，进而导致体感诱发电位（SSEP）消失。
将对接受L2-L3至L5-S1节段ALIF手术的患者在手术过程中的神经监测变化进行研究，特别关注放置牵开器前、牵开器在位时以及移除牵开器后即刻的时间段。
连续45例接受ALIF手术的患者接受了SSEP和血氧饱和度（SaO₂）变化的研究。
若SaO₂降至90%以下，则认为患者出现饱和度下降。若潜伏期增加且波幅降低，则认为患者SSEP异常。
在椎间盘间隙暴露前、牵开器在位暴露期间以及移除牵开器后，连续同时监测SSEP和SaO₂。
23例接受L4-L5节段暴露手术的患者中，有13例在暴露过程中出现SSEP信号消失和SaO₂下降。所有13例患者在移除牵开器后15分钟内饱和度恢复正常，SSEP信号也恢复。这两者均存在显著相关性（p<0.001）。
本研究表明，接受L4-L5节段ALIF手术的大多数（57%）患者的左髂血管受到足够压迫，导致通过脉搏血氧测定法测得的远端饱和度下降。这种血管受压情况以及饱和度恢复正常，与用于暴露的牵开器放置和移除后不久SSEP出现的变化相关。其机制似乎是一种短暂性缺血反应。SSEP信号未能恢复可能提示左髂动脉血栓形成。
