Radiological Outcomes of Unilateral Laminotomy for Bilateral Decompression in Lumbar Spinal Stenosis With and Without Discectomy.

BACKGROUND: Unilateral laminotomy for bilateral decompression (ULBD) is a minimally invasive surgical technique widely used in patients with lumbar spinal stenosis and low-grade spondylolisthesis. However, few studies have investigated the long-term effects of the unilateral approach of ULBD on postoperative coronal imbalance, and the effect of additional discectomy on ULBD has not yet been evaluated in detail. METHODS: Sixty-one patients with lumbar spinal stenosis who underwent ULBD with or without discectomy were identified. The ULBD with discectomy group included 27 patients, and the ULBD without discectomy group included 34 patients. We analyzed the changes in various radiographic parameters, such as global lordosis (GL), segmental lordosis (SL), global coronal angle (GCA), segmental coronal angle (SCA), disc height (DH), global range of motion (GROM), and segmental range of motion (SROM) following the surgery and compared these parameters between the two groups. RESULTS: In patients who underwent ULBD with discectomy, segmental coronal angle (SCA) significantly decreased from 0.42 ± 4.41 (°±SD) preoperatively to -0.31 ± 4.87 postoperatively (P = 0.026), while disc height (DH) decreased from 8.80 ± 2.49 (mm ± SD) to 7.32 ± 2.60 (P < 0.001). These findings suggest a reduction in convexity as disc height decreased on the laminotomy side. However, the absolute SCA value tended to approach 0° postoperatively regardless of discectomy, indicating that the preoperative scoliosis has improved. In both groups, the lordotic angles and range of motion (ROM) parameters showed no changes before and after surgery. CONCLUSIONS: ULBD preserved lumbar lordosis and motion with or without discectomy during the 2-year follow-up period. Improvement in coronal balance was observed after ULBD regardless of discectomy, without significant negative effects on sagittal and coronal spine stability.

Temporal trends (2004-2009) of imposex in rock shells Thais clavigera collected along the Korean coast associated with tributyltin regulation in 2003 and 2008.

We investigated the temporal trend in contamination of butyltin compounds (BTs) along the Korean coast using imposex and tributyltin (TBT) burden in gastropods (Thais clavigera) as a biomonitor. Thais clavigera were collected from 26 locations with different shipping activities between 2004 and 2009 after restrictions on TBT-based antifouling paints were imposed in Korea. In the present study, imposex indices and TBT tissue concentrations significantly decreased over time from 2004 to 2009, confirming the effectiveness of TBT regulation. However, imposex in 2009 samples was still found. Significantly high imposex indices and TBT tissue residues were found in large ports containing commercial and ferry services compared with small ports and background areas. Imposex indices in background areas had decreased to zero, suggesting recovery from imposex caused by BT contamination. These results suggest that recovery from TBT contamination occurs faster in areas with very low maritime activities than areas with high maritime activities.

Carbon and nitrogen status of litterfall, litter decomposition and soil in even-aged larch, red pine and rigitaeda pine plantations.

The carbon (C) and nitrogen (N) status in forest ecosystems can change upon establishment of plantations because different tree species have different nutrient cycling mechanisms. This study was carried out to evaluate C and N status of litterfall, litter decomposition and soil in three adjacent plantations consisting of one deciduous (larch: Larix leptolepis) and two evergreen (red pine: Pinus densiflora; rigitaeda pine: P. rigida x P. taeda) species planted in the same year (1963). Both the pine plantations showed comparatively higher C input from needle litter but significantly lower N concentration and input than the larch plantation (P < 0.05). During the decomposition process, the deciduous larch needle litter showed low C concentration and C remaining in soil, but high N concentration and N remaining in soil compared to the two evergreen pine needle litters. However, the soil C and N concentration and their content at a soil depth of 0-10 cm were not affected significantly (P > 0.05) by the plantation type. These results demonstrate the existence of considerable variation in C and N status resulting from needle litter input and litter decomposition in these three plantations grown at sites with similar environmental conditions.