Minimally Invasive Keyhole Interlaminar Detethering for Symptomatic Fatty Filum Terminale in Pediatric Patients: An Operative Technique

OBJECTIVE: Fatty filum terminale (FFT) is a common cause of tethered cord syndrome (TCS) in children. Traditional detethering often requires laminectomy, which increases surgical trauma and complications. This study aimed to evaluate the safety and efficacy of a minimally invasive keyhole interlaminar approach for FFT. METHODS: The study is a retrospective study. We analyzed 17 pediatric patients with symptomatic FFT who underwent keyhole interlaminar detethering between January 2020 and February 2021. A 1-2 cm midline incision was made at the L3-L4 interlaminar space to establish a working channel without bony removal. Microsurgical detethering was performed under neurophysiological monitoring. Preoperative and postoperative MRI was used to assess detethering, and neurological function was evaluated using the Spina Bifida Neurological Scale (SBNS). RESULTS: All 17 patients underwent successful surgery with no intraoperative complications or conversions to open procedures. Postoperative MRI confirmed complete filum transection. The mean follow-up duration was 33 ± 5 months. The median SBNS score was 14 preoperatively and 15 at the final follow-up. After surgery, complete recovery was achieved in 14 patients (82%), while 3 patients (18%) experienced recovery with mild residual deficits. No late complications were observed in the follow up visit. CONCLUSION: The keyhole interlaminar approach is a safe and effective technique for FFT detethering in children. It offers reduced surgical trauma, faster recovery, and satisfactory neurological improvement, representing a promising alternative to conventional surgery.