The Ligamentotactic Effect on a Herniated Disc at the Level Adjacent to the Anterior Lumbar Interbody Fusion : Report of Two Cases

The authors report two cases of spontaneous regression of disc herniation at the level adjacent to the anterior lumbar interbody fusion (ALIF) level. This phenomenon may be due to the increased tension on the posterior longitudinal ligament (PLL) by appropriate restoration of the disc height and lumbar lordosis, which is a mechanism similar to ligamentotaxis applied to the thoracolumbar burst fracture.

A Morphometric Analysis of Neuroforamen in Grade I Isthmic Spondylolisthesis by Anterior Lumbar Interbody Fusion with Pedicle Screw Fixation

OBJECTIVES: The aim of this study was to evaluate the morphometric changes in neuroforamen in grade I isthmic spondylolisthesis by anterior lumbar interbody fusion (ALIF). METHODS: Fourteen patients with grade I isthmic spondylolisthesis who underwent single level ALIF with percutaneous pedicle screw fixation were enrolled. All patients underwent standing lateral radiography and magnetic resonance imaging (MRI) before surgery and at 1 week after surgery. For quantitative analysis, the foraminal height, foraminal width, epidural foraminal height, epidural foraminal width, and epidural foraminal area were evaluated at the mid-portion of 28 foramens using T2-weighted sagittal MRI. For qualitative analysis, degree of neural compression in mid-portion of 28 foramens was classified into 4 grades using T2-weighted sagittal MRI. Clinical outcomes were assessed using Visual Analogue Sale (VAS) scores for leg pain and Oswestry disability index before surgery and at 1 year after surgery. RESULTS: The affected levels were L4-5 in 10 cases and L5-S1 in 4. The mean foraminal height was increased (p<0.001), and the mean foraminal width was decreased (p=0.014) significantly after surgery. The mean epidural foraminal height (p<0.001), epidural foraminal width (p<0.001), and epidural foraminal area (p<0.001) showed a significant increase after surgery. The mean grade for neural compression was decreased significantly after surgery (p<0.001). VAS scores for leg pain (p=0.001) and Oswestry disability index (p=0.001) was decreased significantly at one year after surgery. CONCLUSION: Foraminal stenosis in grade I isthmic spondylolisthesis may effectively decompressed by ALIF with percutaneous pedicle screw fixation.

Huge Cyst Formation after Gamma Knife Radiosurgery for Arteriovenous Malformation: A Case Report

Radiosurgery is effective in obliterating cerebral arteriovenous malformation(AVM), and delayed cyst formation after radiosurgery is very rare. An 18-year-old man underwent Gamma Knife radiosurgery for arteriovenous malformation located in the left frontotemporal area, which had manifested with hemorrhaging. The 15,01cm3 nidus was covered with a 50% isodose volume. A central dose of 50Gy was used to obtain a marginal dose of 25Gy. One year later, he developed headache and right hemiparesis. MRI showed a huge, multilobulated cyst around the AVM. Follow-up cerebral angiography showed partial obliteration of the AVM nidus. Removal of cystic fluid(about 70cc) was done by stereotactic method, which was revealed as translucent, xanthochromic but had no tumor cell. Two months later, reaccumulation of the cyst was seen on the follow-up MRI insertion setting of Ommaya reservoir was performed. For the diagnosis of complications after radiosurgery for AVM, follow-up study, will be needed.