Walters Rebecca, Rahmat Razmi, Fraser Robert, Moore Robert
Institute of Medical and Veterinary Science, The Adelaide Centre for Spinal Research, Adelaide, P.O. Box 14, Rundle Mall, SA 5000, Australia.
Eur Spine J. 2006 Sep;15(9):1397-403. doi: 10.1007/s00586-006-0144-6. Epub 2006 Jul 8.
Infection can occur after any spinal procedure that violates the disc and although it is not common, the potential consequences are serious. Treatment of discitis is not always successful and the key to management is prevention. Intradiscal prophylaxis with antibiotic is routinely used in spinal surgery, but there is a limited understanding of how well antibiotics can enter the avascular disc after intravenous injection. An in vivo ovine study to optimise prophylactic and parenteral treatment of discitis is described to assess the effectiveness of cephazolin in preventing and treating infection. The concentration of cephazolin was measured in disc tissue from normal and degenerate sheep discs to determine if cephazolin can enter the disc and if disc degeneration affects antibiotic uptake. Fourteen sheep were deliberately inoculated with bacteria to induce discitis. Eight sheep ("prophylaxis" group) were given either a 0, 1, 2 or 3 g dose of prophylactic cephazolin before inoculation while the remaining sheep ("treatment" group) were treated with cephazolin commencing 7 days after inoculation for 21 days at a dose of 50 mg/kg/day. Histopathology and radiography were used to assess the effect of the different treatments. Cephazolin was given 30 min prior to sacrifice and the intradiscal concentration was measured by biochemistry. In the "prophylaxis" group all doses of antibiotic provided some protection against infection, although it was not dose dependent. In the "treatment" group discitis was confirmed radiologically and histologically in all animals from 2 weeks onwards. Biochemical assay confirmed that antibiotic is distributed throughout the disc but was present in higher concentration in the anulus fibrosus than the nucleus pulposus. This study demonstrated that whilst the incidence of iatrogenic discitis can be reduced by antibiotic prophylaxis, it could not be abolished in all incidences with a broad-spectrum antibiotic such as cephazolin. Furthermore, antibiotics were ineffective at preventing endplate destruction once an intradiscal inoculum was established.
任何侵犯椎间盘的脊柱手术都可能引发感染，尽管这种情况并不常见，但潜在后果却很严重。椎间盘炎的治疗并非总能成功，而管理的关键在于预防。脊柱手术中常规使用抗生素进行椎间盘内预防，但对于静脉注射后抗生素进入无血管椎间盘的效果了解有限。本文描述了一项体内绵羊研究，旨在优化椎间盘炎的预防性和非肠道治疗，以评估头孢唑林预防和治疗感染的有效性。测量了正常和退变绵羊椎间盘组织中头孢唑林的浓度，以确定头孢唑林是否能进入椎间盘以及椎间盘退变是否会影响抗生素的摄取。十四只绵羊被故意接种细菌以诱发椎间盘炎。八只绵羊（“预防”组）在接种前分别给予0、1、2或3克剂量的预防性头孢唑林，而其余绵羊（“治疗”组）在接种后7天开始用头孢唑林治疗，剂量为50毫克/千克/天，持续21天。组织病理学和放射学用于评估不同治疗的效果。在处死前30分钟给予头孢唑林，并通过生物化学方法测量椎间盘内浓度。在“预防”组中，所有剂量的抗生素都提供了一定的抗感染保护，尽管这并非剂量依赖性。在“治疗”组中，从2周起所有动物经放射学和组织学证实患有椎间盘炎。生物化学分析证实抗生素分布于整个椎间盘，但纤维环中的浓度高于髓核。这项研究表明，虽然抗生素预防可降低医源性椎间盘炎的发生率，但使用头孢唑林等广谱抗生素并不能消除所有病例中的感染。此外，一旦建立椎间盘内接种物，抗生素在预防终板破坏方面无效。
