The association of posterior ring apophysis separation (PRAS) with lumbar disc herniation (LDH) is uncommon and represents a true subgroup of disc herniation mainly seen in the adolescent population. The objective of this study was to describe a decade of experience in the care of adult patients with PRAS with LDH, giving particular attention to its diagnosis, surgical treatment, and outcome.
Methods. This retrospective study focuses on a case series of adult patients with PRAS associated with LDH who underwent surgery for lumbar disc disease in the author’s neurosurgical department between 1999 and 2008. Posterior ring apophysis separation was diagnosed in 87 (5.35%) of 1625 patients surgically treated for LDH; these patients made up the PRAS group. During a 6-month period in 2005, LDH without PRAS was diagnosed in 89 consecutive patients at the same facility; these patients constituted the control group. Presenting symptoms, physical examination findings, and preoperative imaging results were obtained from medical records. Immediate operative results were assessed, as were complications, long-term outcome, and the need for repeat surgery.
Results. This study is the first to document the distinguishing features between adult patients with and those without PRAS. The difference in average age was statistically significant (p < 0.001) between the study group (36.22 years) and the control group (44.30 years), as was the incidence of male patients (86.20% vs 71.91%, p = 0.020), incidence of military patients (74.71% vs 57.30%, p = 0.015), average duration of symptoms (16.13 vs 8.4 months, p = 0.016), and incidence of reactive scoliosis (19.54% vs 4.49%, p = 0.002). The most common anatomical location of disc herniation in the PRAS group was L5–S1 (51.72%) versus L4–L5 (53.93%) in the control group (p = 0.017). In terms of previous injury, motor deficits, back and/or leg pain, lateral or central location of LDH, mean anteroposterior diameter of disc herniation, hard or soft discs, and surgical complications, there was no statistical difference between the 2 patient groups. Similarly, there was no difference in recurrence rates and clinical outcomes between the patients with or without PRAS.
Conclusions. Posterior ring apophysis separation with LDH is probably more common in adults than is generally recognized. It must be suspected when young male patients with persistent sciatic scoliosis and no history of injury show signs of calcified LDH. Computed tomography scanning with sagittal reconstructions is the procedure of choice for diagnosing. The L5–S1 intervertebral disc level is most commonly affected, especially the superior endplate of S-1. This condition needs more extensive surgical exposure and resection to relieve the nerve impingement. The occurrence of an apophyseal lesion was not associated with recurrent disc herniation or a fair outcome.