Spinal stenosis is a common condition in elderly individuals. Many patients are unresponsive to the conventional treatment. If the transforaminal epidural block does not exert a sufficient treatment effect, percutaneous transforaminal epidural adhesiolysis (PTFA) through the safe-triangle approach using an inflatable balloon catheter can reduce the patients’ pain and improve their functional capacity. We aimed to evaluate the safety and efficacy of the Kambin’s-triangle approach for PTFA using an inflatable balloon catheter and compare this approach to the traditional safe-triangle approach. Thirty patients with chronic unilateral L5 radiculopathy were divided into two groups: the safe-triangle-approach and Kambin’s-triangle-approach groups, with 15 patients each. The success rate of the procedure was assessed. Pain and dysfunction were assessed using the Numerical Rating Scale and Oswestry Disability Index, respectively, before the procedure and at 1 and 3 months after the procedure. The success rate of the procedure was high in both the groups, with no significant difference between the groups. The Numerical Rating Scale and Oswestry Disability Index scores significantly decreased 3 months after the procedure in both the groups, with no significant difference between the groups. For patients in whom the safe-triangle approach for PTFA is difficult, the Kambin’s-triangle approach could be an alternative.

Rationale: Perineural cysts in the spinal canal are usually asymptomatic. However, symptoms can occur when the cyst becomes large enough to compress a nerve root. There are still no established treatment options for this disease. In this report, we describe a case of successful decompression of the large symptomatic perineural cyst using epiduroscope. Patient concerns: A 42-year-old male patient visited our pain center complaining of discomfort and pain in his right posterior thigh. Magnetic resonance imaging of the patient showed a large perineural cyst (53 × 31 × 21 mm) compressing the right S1 nerve. No other abnormalities that would explain the patient's symptoms were identified. Diagnosis: Perineural cyst at the right S1 nerve. Interventions: We performed an epiduroscopic decompression of the perineural cyst. After advancing the epiduroscope and locating the cyst, we used the laser to make a hole in the cyst wall. Then, the epiduroscope was advanced into the cyst, and the cystic fluid was aspirated. Outcomes: The symptoms of the patient were relieved after the procedure, without any complications. There was no recurrence of symptoms until 6 months after the procedure. Lessons: The epiduroscope is a minimally invasive method which can be used safely for decompression of symptomatic perineural cysts in the spinal canal.