Individual psychological and social work factors, as well as worker-employer relations are also likely to be associated with time and rates of recovery.A Finnish study of return to work in patients with spinal stenosis treated by surgery found that: (1) none of the patients who had retired before the operation returned to work afterward. (2) The variables that predicted postoperative ability to work for women were: being fit to work at the time of operation, age < 50 years at the time of operation, and duration of lumbar spinal stenosis symptoms < 2 years. (3) For men, these variables were: being fit to work at the time of operation, age < 50 years at the time of operation, no prior surgery, and the extent of the surgical procedure equal to or less than one laminectomy. Womens and mens working capacity do not differ after lumbar spinal stenosis operation. If the aim is to maximize working capacity, then, when a lumbar spinal stenosis operation is indicated, it should be performed without delay. In lumbar spinal stenosis patients who are > 50 years old and on sick leave, it is unrealistic to expect that they will return to work. Therefore, after such an extensive surgical procedure, re-education of patients for lighter jobs could improve the chances of these patients returning to work.In a related Finnish study, a total of 439 patients operated on for lumbar spinal stenosis during the period 1974–1987 was re-examined and evaluated for working and functional capacity approximately 4 years after the decompressive surgery.
Calcium citrate is the calcium salt of citric acid. It is commonly used as a food additive (E333), usually as a preservative, but sometimes for flavor. In this sense, it is similar to sodium citrate. Calcium citrate is also found in some dietary calcium supplements (e.g. Citracal or Caltrate). Calcium makes up 24.1% of calcium citrate (anhydrous) and 21.1% of calcium citrate (tetrahydrate) by mass. The tetrahydrate occurs in nature as the mineral Earlandite. In 2019, it was the 225th most commonly prescribed medication in the United States, with more than 2 million prescriptions. Chemical properties
Calcium citrate is sparingly soluble in water. Needle-shaped crystals of tricalcium dicitrate tetrahydrate [Ca3(C6H5O7)2(H2O)2]·2H2O were obtained by hydrothermal synthesis. The crystal structure comprises a three-dimensional network in which  eightfold coordinated Ca2+ cations are linked by citrate anions and hydrogen bonds between two non-coordinating crystal water molecules and two coordinating water molecules. Production
Calcium citrate is an intermediate in the isolation of citric acid from the fungal fermentation process by which citric acid is produced industrially. The citric acid in the broth solution is neutralized by limewater, precipitating insoluble calcium citrate. This is then filtered off from the rest of the broth and washed to give clean calcium citrate. 3 Ca(OH)2(s) + 2 C6H8O7(l) → Ca3(C6H5O7)2(s) + 6 H2O(l)The calcium citrate thus produced may be sold as-is, or it may be converted to citric acid using dilute sulfuric acid. Biological role
In many individuals, bioavailability of calcium citrate is found to be equal to that of the cheaper calcium carbonate.