Introduction: Tethering after spinal surgery is caused by adhesions that arise from intradural tissue manipulation. Microsurgical de-tethering is the only treatment for symptomatic patients, but re-tethering occurs commonly and no treatment is widely available to prevent this complication.We applied human amniotic membrane (HAM) grafts, which are immune-privileged and known to possess anti-fibrogenic properties, in patients requiring microsurgical de-tethering. For this first-in-human use, we evaluated the safety and potential efficacy of these grafts for preventing re-tethering.
Methods: We retrospectively reviewed the medical records of all patients who required de-tethering surgery and received a HAM graft between 2013 and 2016 at our institution after various previous intradural spinal surgeries. In all 14 cases, intradural lysis of adhesions was achieved, a HAM graft was sewn in place intradurally, and a dural patch was closed in a watertight fashion over the graft.
Results: Fourteen patients had received HAM grafts to prevent re-tethering. All patients had at least 6 months of follow-up (mean follow-up, 14 months). Re-tethering was noted in only 1 patient. Surgical re-exploration showed that the re-tethering occurred caudal to the edge of the HAM graft, with no tethering underneath the original graft. No complications were attributed specifically to the HAM graft placement.
Conclusions: This first-in-human series provides evidence that HAM grafts are a safe and potentially efficacious method for preventing re-tethering after microsurgical intradural lysis of adhesions. These results lay the groundwork for further prospective controlled trials in patients with this difficult-to-treat pathology.
Patient Care: This work provides the basis for safely applying human amniotic membrane grafts in future studies of intradural surgery. It provides some evidence that the grafts may have therapeutic properties that help prevent re-tethering and adhesion formation in high-risk patients.
Learning Objectives: By the conclusion, participants should be able to: 1.) Describe the potential therapeutic characteristics of human amniotic membrane grafts, 2.) Understand the potential role for HAM grafts in preventing arachnoid adhesions after intradural surgery.