Current surgical options for treating non-traumatic adhesive syringomyelia, particularly in patients with a history of previous spinal canal surgery, lack clear standardization and frequently lead to common complications such as recurrent adhesions, tube disconnections, and neurological injuries related to myelotomy, resulting in the need for multiple revision surgeries. This study aims to introduce a novel, minimally invasive technique of modified subarachnoid-subarachnoid (S - S) bypass procedure for syringomyelia associated with postoperative arachnoid adhesions and to prospectively evaluate its surgical outcomes.This prospective study included 11 consecutive patients with syringomyelia related to postoperative arachnoid adhesions who underwent modified S-S bypass surgery, with a mean follow-up period of 18.3 months (range: 16-20 months). Neurological function was assessed using standardized grading systems, and changes in syrinx size were evaluated using MRI.Ten patients demonstrated clinical improvement, while one patient remained stable. Notably, the preoperative and postoperative ASIA motor and sensory scores showed significant improvement (88.45 ± 11.01 vs. 89.64 ± 9.99, p < 0.05; 200.73 ± 15.52 vs. 203.09 ± 15.29, p < 0.001). The mean syrinx tension index postoperatively was significantly lower than the preoperative value (74.28 ± 14.34% vs. 29.87 ± 17.62%, p < 0.0001), and the syrinx length was also significantly reduced (9.46 ± 4.59 vs. 8.00 ± 6.05, p < 0.05).This study highlights that the modified S-S bypass can be performed without myelotomy or intratubal interaction with CSF circulation, representing not only a safe and effective surgical technique but also a potentially more physiological approach for treating syringomyelia associated with postoperative arachnoid adhesions.© 2025. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.