Dermatomal Distribution and Radiocontrast Study of Ultrasound Guided Sacral Foramen Injection, a Modification of Sacral Erector Spinae Plane Block

AbstractBackgroundWe evaluated the analgesic efficacy of modified sacral erector spinae plane block (S-ESPB) in patients of carcinoma cervix undergoing intracavitary brachytherapy through a single-arm prospective study.MethodsTen consecutive consenting patients scheduled for intracavitary or interstitial brachytherapy for carcinoma cervix were recruited in the study. The patients received modified S-ESPB for the therapy, supplemented by sedoanalgesia. Dermatomal mapping and monitoring of pain score, vital signs, and additional fentanyl requirements were monitored up to 24 hrs for each patient. Radiocontrast was injected along with the local anesthetic (LA) in each patient, analyzed by CT scan later on. Summary statistics were calculated.ResultsS-ESPB block provided surgical anaesthesia for all patients. Median cumulative fentanyl requirement was122 mcg (interquartile range: 50 to 250 mcg) over 24 hrs. Mapping of dermatomal sensation revealed sensory loss for upto 6 hours in the S2 - S5 dermatomes in all patients. Radiological evaluation of contrast spread demonstrated spread along the presacral area, sciatic and pudendal nerve tracts and broad ligament.ConclusionThe use of modified S-ESPB resulted in clinically useful analgesia in patients undergoing intracavitary brachytherapy. We demonstrated that anesthesia could be obtained in the distribution of sacral, sciatic, and pudendal nerve distributions using this method. <br>

一、研究背景与目的
本研究通过单臂前瞻性临床试验，评估改良骶棘肌平面阻滞（sacral erector spinae plane block, S-ESPB）用于宫颈癌患者接受腔内近距离放射治疗时的镇痛效果。
二、研究方法
本研究共纳入10名连续入组且签署知情同意书的宫颈癌患者，所有患者均拟接受腔内或间质近距离放射治疗。所有受试者均接受改良S-ESPB阻滞，并辅以镇静镇痛方案。对每名患者开展为期24小时的监测，内容包括皮节感觉映射、疼痛评分、生命体征及追加芬太尼的用药需求。所有患者均在局部麻醉药（local anesthetic, LA）中加入放射造影剂，术后通过CT扫描对造影剂扩散情况进行分析，同时计算相关汇总统计量。
三、研究结果
所有患者均通过S-ESPB阻滞获得手术麻醉效果。24小时内芬太尼累计使用量的中位数为122 mcg（四分位间距：50~250 mcg）。皮节感觉映射结果显示，所有患者的S2~S5皮节均出现最长达6小时的感觉缺失。造影剂扩散的影像学评估显示，造影剂沿骶前区域、坐骨神经与阴部神经通路以及子宫阔韧带扩散。
四、研究结论
改良S-ESPB的应用可使接受腔内近距离放射治疗的患者获得具有临床实用价值的镇痛效果。本研究证实，该阻滞方法可实现骶神经、坐骨神经及阴部神经支配区域的麻醉。