Anesthetic Management in a Patient With Tethered Spinal Cord Syndrome Undergoing Knee Replacement Surgery

Tethered spinal cord syndrome (TSCS) is a neurological disorder characterized by tissue attachments limiting spinal cord movement, which can result in the conus medullaris terminating at a level lower than the typical L1. This abnormality can cause significant complications during spinal anesthesia due to the risk of injury at the traditional puncture sites of L4-L5. This case report discusses the anesthetic management of a 65-year-old female patient diagnosed with TSCS with her spinal cord extending to L5-S1. She presented for a right total knee replacement. The patient had a history of successful spinal anesthesia for her previous left knee replacement but was apprehensive about repeating the procedure due to her spinal anatomy and the associated risks. A thorough preoperative assessment was conducted with this patient. This included a detailed MRI review by a radiologist and a neurosurgeon, which highlighted the risks associated with spinal anesthesia. Given the minimal cerebrospinal fluid around critical levels of the spinal cord, the risk of injury during spinal anesthesia was significant. After discussion with the patient about the risks and benefits of each anesthetic option, the care team and patient jointly decided that general anesthesia would offer the safest approach. General anesthesia was administered successfully with standard intraoperative monitoring and airway management. A preoperative adductor nerve block was also performed to manage postoperative knee pain. The patient emerged from anesthesia without complications, with stable vital signs and good neurovascular function. The interdisciplinary approach and careful preoperative planning were crucial to achieve a positive outcome in this case. This case highlights the importance of individualized anesthetic planning for patients with TSCS. It underscores the need for thorough preoperative assessment and patient-centered care to determine the safest anesthetic approach. This report also reviews the mechanisms of spinal cord injury during neuraxial anesthesia in TSCS, discusses epidural anesthesia as an alternative, and synthesizes evidence-based recommendations for preoperative assessment in the absence of formal guidelines. Further research and the development of formal guidelines for anesthetic management in TSCS are warranted to improve patient safety and outcomes.