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Does minimally invasive lumbar disc surgery result in less muscle injury than conventional surgery? A randomized controlled trial.
Arts, M, Brand, R, van der Kallen, B, Lycklama à Nijeholt, G, Peul, W
European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society. 2011;(1):51-7
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Abstract
The concept of minimally invasive lumbar disc surgery comprises reduced muscle injury. The aim of this study was to evaluate creatine phosphokinase (CPK) in serum and the cross-sectional area (CSA) of the multifidus muscle on magnetic resonance imaging as indicators of muscle injury. We present the results of a double-blind randomized trial on patients with lumbar disc herniation, in which tubular discectomy and conventional microdiscectomy were compared. In 216 patients, CPK was measured before surgery and at day 1 after surgery. In 140 patients, the CSA of the multifidus muscle was measured at the affected disc level before surgery and at 1 year after surgery. The ratios (i.e. post surgery/pre surgery) of CPK and CSA were used as outcome measures. The multifidus atrophy was classified into three grades ranging from 0 (normal) to 3 (severe atrophy), and the difference between post and pre surgery was used as an outcome. Patients' low-back pain scores on the visual analogue scale (VAS) were documented before surgery and at various moments during follow-up. Tubular discectomy compared with conventional microdiscectomy resulted in a nonsignificant difference in CPK ratio, although the CSA ratio was significantly lower in tubular discectomy. At 1 year, there was no difference in atrophy grade between both groups nor in the percentage of patients showing an increased atrophy grade (14% tubular vs. 18% conventional). The postoperative low-back pain scores on the VAS improved in both groups, although the 1-year between-group mean difference of improvement was 3.5 mm (95% CI; 1.4-5.7 mm) in favour of conventional microdiscectomy. In conclusion, tubular discectomy compared with conventional microdiscectomy did not result in reduced muscle injury. Postoperative evaluation of CPK and the multifidus muscle showed similar results in both groups, although patients who underwent tubular discectomy reported more low-back pain during the first year after surgery.
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Modulation of calcium oxalate monohydrate crystallization kinetics by urine of preterm neonates.
Schell-Feith, EA, Que, I, Kok, DJ, Kist-Van Holthe, JE, Kühler, E, Brand, R, Papapoulos, SE, van der Heijden, BJ
American journal of kidney diseases : the official journal of the National Kidney Foundation. 2001;(6):1229-34
Abstract
Preterm neonates frequently develop nephrocalcinosis (NC). However, the cause has not yet been elucidated. This study focuses on the effects of urine from preterm neonates on crystallization kinetics. Urine samples were collected and renal ultrasound examinations of preterm neonates (gestational age < 32 weeks) were performed during the first weeks of life, at term, and ages 6, 12, and 24 months. The effect of urine on crystallization was determined using a seeded crystal growth system, which measures the square root of solubility product ( radicalLc), percentage of growth inhibition (GI), and agglomeration inhibition ([tm]) of calcium oxalate crystals. Data for preterm neonates in the first weeks of life (n = 19) were compared with those for full-term neonates (n = 17) and healthy adults. Moreover, the correlation between [tm] and urinary (U)citrate level was studied. Mean radicalLc (0.27 +/- 0.1 versus 0.36 +/- 0.08 mmol/L) and mean [tm] (81 +/- 32 versus 143 +/- 97 minutes) were lower and mean Ucalcium-creatinine (2.20 +/- 1.74 versus 0.46 +/- 0.73 mol/mol) and Uoxalate-creatinine ratios (0.39 +/- 0.21 versus 0.16 +/- 0.09 mol/mol) were greater in preterm neonates in the first weeks of life compared with full-term neonates (p < 0.05). Furthermore, [tm] was less than the lower limit for healthy adults for all but one preterm neonate; [tm] increased and Ucalcium-creatinine and Uoxalate-creatinine ratios decreased with age (p < 0.005). There was a correlation between [tm] and citrate excretion (coefficient of 38; P < 0.001). Patients with and without NC at term did not differ statistically in mean radicalLc, percentage of GI, or [tm]. In conclusion, urine from preterm neonates in the first weeks of life is highly supersaturated and has a defective ability to inhibit calcium oxalate crystal agglomeration. This ability improves with age and is citrate mediated. We suggest that both the high level of supersaturation and defective ability to inhibit calcium oxalate crystal agglomeration contribute to the high incidence of NC.