Co-existence of Lumbar Disc Herniation and Posterior Ring Apophyseal Fracture: It Is Not Rare and Computed Tomography Is Useful

Introduction Posterior ring apophyseal fracture (PRAF) is characterized by the separation of bone fragments and sometimes coexists with lumbar disc herniation (LDH). However, how often these conditions coexist and the details of the clinical course remain unclear. Methods We analyzed 200 patients who underwent surgical treatment for LDH at our hospital from January 2016 to December 2020. Among these, we reviewed 21 patients who underwent microendoscopic surgery to treat PRAF. They consisted of 11 male and 10 female patients, ranging in age from 15 to 63 years. The average age was 32.8 months, and the average follow-up period was 39.8 years. We performed simple roentgenography and magnetic resonance imaging for all patients and computed tomography for about 80% of the patients. We evaluated the type of PRAF fragment (Takata classification), disease level, Japanese Orthopedic Association (JOA) score, Roland-Morris Disability Questionnaire (RDQ) score, operating time, intraoperative blood loss, and perioperative complications. Results A total of 10.5% of patients with LDH also had PRAF. The mean JOA score significantly improved from 10.6 ± 5.7 points before surgery to 21.4 ± 5.1 points at the final observation (p < 0.05). The mean RDQ score significantly improved from 17.1 ± 4.5 preoperatively to 5.5 ± 0.5 at the final observation (p < 0.05). The average operation time was 88.6 minutes. There were no complications requiring early surgery that were due to postoperative infection or epidural hematoma, but one patient required reoperation. Conclusion This study showed that PRAF coexisted with LDH in about 10% of cases, and the outcomes of surgical treatment were generally good. Computed tomography is recommended to improve the diagnostic rate and assist with surgical planning and intraoperative decision-making.