Gale D W, Valley M A, Rogers J N, Poterack K A
Department of Anesthesiology, Wilford Hall Medical Center, Lackland AFB, Texas.
Reg Anesth. 1994 Nov-Dec;19(6):395-401.
Neurolytic nerve block, using either alcohol (A) or phenol (P), is frequently used to treat intractable pain. However, these agents may disrupt the integrity of prosthetic vascular grafts. To investigate this possibility, the tensile strength of Dacron (Meadox Medicals, Oakland, NJ) and Gore-Tex (W.L. Gore Associates, Flagstaff, AZ) vascular grafts was determined after in vitro exposure to various clinically used concentrations of A or P.
Segments of Dacron and Gore-Tex graft were placed in the following solutions: saline (S), 6% and 9% P, and 25%, 50%, 75%, and 100% A, and stored at 23 degrees +/- 1 degree C for 72 hours. Axial maximum load (in kilonewtons, KN) and strain (in mm/mm) were determined with an Instron universal testing machine (Instron Corporation, Camden, MA). Samples from the S, 9% P, and the 100% A groups were evaluated using a scanning electron microscope.
Dacron tensile strength decreased a maximum of 23% after exposure to 50%, 75%, and 100% A. Dacron strain capacity decreased after exposure to A (50%, 75%, 100%) and P (6%, 9%). Scanning electron microscope of both P and A showed significant degradation. No changes were found in the Gore-Tex group after exposure to P or A, however, scanning electron microscope of the 100% A sample showed moderate fiber degradation.
The study shows that Dacron woven grafts are degraded by concentrations of A of at least 50%, and to a lesser extent, concentrations of at least 6%, while Gore-Tex had only minimal changes. While neurolytic block offers distinct advantages in patients with terminal cancer pain, the findings suggest that the use of more conservative modalities, such as oral medication regimens, be considered for the treatment of intractable pain in patients with vascular prosthetic grafts that are proximate to the proposed site of neurolysis.
使用乙醇（A）或苯酚（P）进行的神经溶解阻滞常用于治疗顽固性疼痛。然而，这些药物可能会破坏人工血管移植物的完整性。为了研究这种可能性，在体外将涤纶（Meadox Medicals，奥克兰，新泽西州）和戈尔特斯（W.L. Gore Associates，弗拉格斯塔夫，亚利桑那州）血管移植物暴露于各种临床使用浓度的A或P后，测定其拉伸强度。
将涤纶和戈尔特斯移植物段置于以下溶液中：生理盐水（S）、6%和9%的P，以及25%、50%、75%和100%的A，并在23摄氏度±1摄氏度下储存72小时。使用英斯特朗万能材料试验机（英斯特朗公司，卡姆登，马萨诸塞州）测定轴向最大载荷（以千牛顿计，kN）和应变（以毫米/毫米计）。使用扫描电子显微镜对来自S、9%P和100%A组的样本进行评估。
暴露于50%、75%和100%的A后，涤纶的拉伸强度最大降低了23%。暴露于A（50%、75%、100%）和P（6%、9%）后，涤纶的应变能力降低。P和A的扫描电子显微镜均显示有明显降解。然而，戈尔特斯组在暴露于P或A后未发现变化，但100%A样本的扫描电子显微镜显示有中度纤维降解。
该研究表明，至少50%浓度的A会使编织涤纶移植物降解，至少6%浓度的A降解程度较小，而戈尔特斯的变化极小。虽然神经溶解阻滞在终末期癌症疼痛患者中具有明显优势，但研究结果表明，对于拟进行神经溶解部位附近有人工血管移植物的顽固性疼痛患者，应考虑使用更保守的治疗方式，如口服药物治疗方案。
