High calcium diet alleviates 5/6 nephrectomy-induced bone deteriorations of lumbar vertebrae in mice.

Dietary calcium (Ca) supplementation has beneficial effects on bone health. However, it is not clear whether a high calcium diet (HCD) following 5/6 nephrectomy (5/6 Nx) is beneficial to bone health. The aim of the present study was to examine the effects of an HCD on bone metabolism using a chronic kidney disease (CKD) mouse model. Male C57BL/6J mice were divided into three groups: Sham group, 5/6 Nx group and 5/6 Nx + HCD group. Mice were sacrificed 12 weeks post-surgery. Calcium (Ca) and creatinine (Cr) were measured using standard colorimetric methods and picric acid methods, respectively. Bone metabolism-associated markers, FGF-23, PTH, ALP-b and TRAP-5b were measured using ELISA kits. Lumbar vertebrae histomorphological analysis was performed using hematoxylin and eosin staining. The expression of osteoprotegerin (OPG) and receptor activator of nuclear factor κB ligand (RANKL) mRNA was detected using reverse transcription-quantitative polymerase chain reaction. Impaired renal function and histopathological damage was indicated in 5/6 Nx mice. However, HCD had no significant effects on these changes in 5/6 Nx mice. Notably, mineral metabolism disorder and histopathological damage to lumbar vertebrae were markedly improved in HCD-treated 5/6 Nx mice. Compared with 5/6 Nx mice, HCD supplementation significantly elevated the ratio of OPG/RANKL and inhibited RANKL mRNA expression in lumbar vertebrae. To conclude, the present findings indicated that increased Ca intake is effective in increasing bone mineral content of the lumbar vertebrae in 5/6 Nx mice. These results may provide a basis for the clinical use of dietary Ca supplementation as a therapeutic approach to treat CKD-induced disturbance of mineral metabolism and bone loss.

[A comparative study of outcome between single cage and double cages interbody fusion combined with pedicle screw fixation in treatment of isthmic spondylolisthesis].

OBJECTIVE: To compare the clinical effects of isthmic spondylolisthesis by a single cage or double cages interbody fusion combined with pedicle screw fixation. METHODS: The clinical data of 172 patients with isthmic spondylolisthesis underwent surgery from March 2000 to August 2008 were retrospectively analyzed. All cases underwent posterior pedicle screw fixation and interbody fusion, 89 cases with single cage fusion and 83 cases with double cages fusion. In single cage group, there were 56 males and 33 females, aged from 18 to 63 years old with an average of(41.60±8.20) years;25 cases were in L4 segment and 64 cases were in L5;according to the Meyerding standard, 32 cases were I degree, 46 cases were II degree and 11 cases were III degree. In double cage group, there were 49 males and 34 females, aged from 20 to 65 years old with an average of(43.30±6.39) years;21 cases were in L4 and 62 cases were in L5;according to the Meyerding standard, 25 cases were I degrees, 45 cases were II degree, and 13 cases were III degree. The operative time, intraoperative blood loss, postoperative drainage volum, bone fusion rate, intervertebral space height and the improvement of clinical symptoms were compared between two groups. RESULTS: All the operations were successful and all patients were followed up for 18 to 83 months with an average of 4 years and 3 months. The operative time, intraoperative blood loss, postoperative drainage volume in single cage group were less than of double cage group(P<0.05). Two weeks after operation, the intervertebral space height was significantly increased in two groups(P<0.05), and there was no significant difference at the last follow-up between two groups. At 16 months after operation, all bone grafts of patients got bony fusion by X-rays. At the last follow-up, there were no statistically significant difference in JOA, ODI and VAS score between two groups, no pedicle screw loosening and breaking were found. CONCLUSIONS: Single cage interbody fusion combined with pedicle screw fixation is as effective as with double cages interbody fusion in treatment of isthmic spondylolisthesis, it has the advantages of short operative time and less blood loss.

[Treatment of lumbar spondylolisthesis by posterior restoration and three-column fixation].

OBJECTIVE: To investigate the late results of using posterior restoration and three-column fixation to treat lumbar spondylolisthesis. METHODS: One hundred and eighty-four patients with lumbar spondylolisthesis were collected from March 1999 to May 2007, they were treated by posterior restoration and fixation with single nail-grooved tail steel plate and fixed with cage (WDFC). Among these cases, 87 cases were fixed with one WDFC, 97 cases were used two WDFCs. RESULTS: All patients were followed up for 8 to 69 months(averaged 23 months). According to Nakai standard, the results was excellent in 142 cases, good in 34, fair in 8, the excellent and good rates were 95.6%. Seventy-nine vertebraes with I degree spondylolisthesis were reduced after surgery. Eighty-seven vertebraes with II degree spondylolisthesis were reduced except 9 with I degree spondylolisthesis left. Twenty-one with III degree spondylolisthesis were reduced except 5 with I degree spondylolisthesis left; In 2 with IV degree spondylolisthesis, one with I degree spondylolisthesis left and the other with II degree spondylolisthesis left. The follow-up results showed that there was no statistical significance in the height of intervertebral space between preoperation and post-operation, and no recurrence was observed and no single nail-grooved tail steel plate and WDFC were loose or crashed. CONCLUSION: Posterior restoration and three-column fixation is a positive modus operandi to treat lumbar spondylolisthesis,which can reduce excellently,keep the height of intervertebral space and stabilization of segment, obtain high rate of fusion, and cut down complication.