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.

Soil properties of cultivation sites for mountain-cultivated ginseng at local level.

BACKGROUND: Identifying suitable site for growing mountain-cultivated ginseng is a concern for ginseng producers. This study was conducted to evaluate the soil properties of cultivation sites for mountain-cultivated ginseng in Hamyang-gun, which is one of the most well-known areas for mountain-cultivated ginseng in Korea. METHODS: The sampling plots from 30 sites were randomly selected on or near the center of the ginseng growing sites in July and August 2009. Soil samples for the soil properties analysis were collected from the top 20 cm at five randomly selected points. RESULTS: Mountain-cultivated ginseng was grown in soils that varied greatly in soil properties on coniferous, mixed, and deciduous broad-leaved stand sites of elevations between > 200 m and < 1,000 m. The soil bulk density was higher in Pinus densiflora than in Larix leptolepis stand sites and higher in the < 700-m sites than in > 700-m sites. Soil pH was unaffected by the type of stand sites (pH 4.35-4.55), whereas the high-elevation sites of > 700 m were strongly acidified, with pH 4.19. The organic carbon and total nitrogen content were lower in the P. densiflora stand sites than in the deciduous broad-leaved stand sites. Available phosphorus was low in all of the stand sites. The exchangeable cation was generally higher in the mixed and low-elevation sites than in the P. densiflora and high-elevation sites, respectively. CONCLUSION: These results indicate that mountain-cultivated ginseng in Korea is able to grow in very acidic, nutrient-depleted forest soils.

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.