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>

摘要
研究背景：本研究通过单臂前瞻性试验，评估改良骶棘肌平面阻滞（modified sacral erector spinae plane block, S-ESPB）用于接受腔内近距离放疗的宫颈癌患者的镇痛效果。
方法：本研究招募了10名签署知情同意的宫颈癌患者，均拟接受腔内或间质近距离放疗。所有患者在治疗期间接受改良S-ESPB，并辅以镇静镇痛。对每名患者进行长达24小时的皮节映射、疼痛评分、生命体征监测以及追加芬太尼剂量记录。所有患者均在局部麻醉剂（local anesthetic, LA）中注入放射造影剂，后续通过CT扫描进行分析，并计算汇总统计数据。
结果：所有患者均通过S-ESPB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阔韧带扩散。
结论：改良S-ESPB的应用可为接受腔内近距离放疗的患者提供具有临床价值的镇痛效果。本研究证实，该方法可实现骶神经、坐骨神经及阴部神经支配区域的麻醉。