Trauma was identifified as the most common cause, with almost 50% of patients having a history of trauma.  This injury is difficult to diagnosis using plain radiographs or magnetic resonance imaging (MRI). However, this condition can be well recognized using computed tomography (CT) and classified into 4 types: type I, avulsion of the whole posterior limbus; type II, separation fracture of a part of the vertebral body, including the limbus; type III, lateralized chip fractures; and type IV, fractures of the vertebral limbus that span the entire vertebral body. [5 6]Decompression by laminotomy or laminectomy without fusion was the standard treatment of lumbar disc herniations with posterior ring apophysis separation until recently. Regarding the centrally located lesions (types I, II, and IV) causing canal or foraminal stenosis, extensive resection of the superior or inferior adjacent lamina was ecessary. Therefore, bilateral laminotomy or full laminectomy has been suggested by many investigators to be required to remove the large and extensive fragment. Regarding type III, the unilateral surgical procedure could achieve suffificient decompression and function improvement for the lateralized chip fractures, including semi-laminotomy, laminectomy, and microendoscopic discectomy. Nevertheless, the posterior spinal structure destruction resulting from open surgery could affect the postoperative results such as residual low back pain, iatrogenic instability, and epidural scarring. Hence, it is essential to achieve suffificient neural decompression and minimize the surgical trauma, especially for adolescents.
The initial management of lumbar disc herniation in adolescents is the same as in adults and consists of conservative treatment comprising bed rest, analgesic and anti-inflammatory agents, physical therapy and limitation of physical activities [8, 9]. Conservative measures are considered before surgery unless lumbar disc herniation affects the patient’s motor and neurological functions or causing a truly incapacitating pain. There were also reports of successful results from the use of epidural steroid injections as a part of conservative treatments for pediatric lumbar disc herniation . Adolescents are less responsive to conservative treatment than adults and this is mainly attributed to the viscosity and high elasticity of the inter-vertebral disc in adolescents compared with that in adults. Very few clinical studies have reported successful conservative treatment of lumbar disc herniation in adolescents. Kurth et al.  compared outcome of conservative treatment with surgical treatment for 33 children (18 conservatively and 15 surgically treated cases) with a follow-up of 5.4 years, and found no significance between the two groups. DeLuca et al. , however, found that surgical treatment lead to a significant better outcome than conservative treatment by carrying out a similar study on 31 children (8 conservative, 23 surgical) with a 6-year follow-up. Regardless of the controversy, it has been widely agreed by most authors that conservative treatment is not as effective for children lumbar disc herniation as it is for adults [7, 9].
Operative treatment of lumbar disc herniation should be considered when incapacitating pain disables the patient or neurological deficit or after failure of conservative treatment. However, most adolescent lumbar disc herniations with posterior ring apophysis separation do not respond well to conservative treatment and thus require operative intervention. Adolescents who had neurological deficits and progressive nerve root compression underwent early surgical intervention resulting in excellent recovery outcome. Removal of lumbar disc herniation in adolescents was usually difficult because of its viscous and slippery consistency . However, results of surgical treatment in 98% of children are good or excellent, which is much better than that reported in other age groups [11, 12]. The surgical approach should be individualized and the amount of bone removal should be balanced against the risk of developing subsequent spinal deformity in the growing child.
Various techniques have been proposed for the operative treatment of lumbar disc herniations with posterior ring apophysis separation. These include midline incisions and subperiosteal muscle dissections with hemi-laminectomy and partial or complete facetectomy or paramedian incisions with intermuscular dissections for an intertransverse approach; and combined approaches for lumbar disc herniation Adhesion, scar compression, and dura mater fibrosis often occur postoperatively, which may lead to related symptoms. Instability and severe back pain have been reported after an interlaminar approach. These sequestrated fragments may be missed even after full facetectomy and therefore are the cause of persistent radicular pain . Together, minimal internal tissue damage and a smaller surgical incision (approximately 7 mm) reduces the revalidation period, minimizes scar tissue, and reduces complications. Intraoperative bleeding is reduced, and hemostasis can be expected postoperatively. It encourages fast wound healing and reduces the risk of infection.
The clinical symptoms of lumbar disc herniations with posterior ring apophysis separation were mainly caused by the herniated disc as shown by MRI. Because the texture of the bony fragment was hard with sharp edges, it was proper to resect the herniated disc first to obtain a wider operative space, providing the advantages of avoiding nerve root injury and dural tears. After discectomy, burrs and a rongeur should be used to excise the bony fragment step-by-step under visual control. All the loose and mobile fragments should be removed. In contrast, whether the fixed and immobile fragments should be removed will depend on whether they had compressed the nerve root. Those fragments resulting in compression should be removed completely. However, if the fragments are not causing compression, they can be retained to prevent extensive damage to the intervertebral structure, as suggested in some previous studies.