Considerations Before Back Surgery
Orthopaedic surgeons, including Jacob M. Buchowski, MD, were involved in the production of the paper which highlighted a major problem for spinal surgeons and patients undergoing back surgery. Although awareness of the importance of vitamin D has grown in recent years, and supplemental sources are widely available, many patients continue to have deficiencies which affect not only the skeleton but also the immune system and mental health. It may be that patients scheduled for back surgery are tested in the future to ensure adequate levels of vitamin D for healing from surgery, as well as to help with the management of back pain. Pre-surgical guidance, such as asking patients to stop smoking, checking they are free of infection, and monitoring adherence to other pre-surgical requirements regarding medications and supplements may be updated to include assessments of a patient’s vitamin D levels. Those found to be deficient may be advised to delay back surgery and take vitamin D supplements to improve their prognosis after back surgery.
Risk Factors for Low Vitamin D Levels
The study was instigated after Dr Buchowski had a patient in her forties who had a slow recovery after spinal fusion surgery and who subsequently mentioned a diagnosis of vitamin D deficiency. The doctor was prompted to start a screening programme, along with his colleagues at Barnes-Jewish Hospital, of all patients undergoing spinal fusion to check vitamin D levels. More than 300 patients took part in the study, with each undergoing a discectomy with spinal fusion surgery. Patients had an average age of fifty-five, and the majority (53%) were undergoing lumbar spinal fusion. More than half of the patients were female, and nearly half of the patients (41%) were obese. Those patients that were obese were more likely to have insufficient vitamin D levels, as were the smokers in the group, and the small number of black patients included in the study. Those with darker skin do not synthesize vitamin D as easily as their paler counterparts and are often at risk of sub-optimal levels of the nutrient unless it is supplemented.
More Disability and Pain with Inadequate Vitamin D
Levels of vitamin D in the patients tested averaged 28.6ng/ml and 27% of the patients were classed as being deficient in vitamin D (where levels are below 20ng/ml). Pain levels were higher in those with inadequate levels of the vitamin, as was bone mineral density, and the prevalence of neurologic deficits. Disability scores were higher amongst the patients with inadequate levels of vitamin D, which could reflect both cause and effect if a patient’s illness and pain prevents them from accessing and preparing healthy and nutritious foods containing vitamin D or from being able to afford supplements if their disability affects their employment status.
Spinal Fusion and Vitamin D
Previous studies have found similar results in orthopedic patients but this is the first to look specifically at those scheduled for spinal fusion, a back surgery which is extremely likely to be affected by any factor influencing bone growth and repair. Although the study has been criticized for not controlling for other potential factors affecting the results, as well as for possible selection bias, the paper still provided food for thought for those attending the conference. Routine screening of vitamin D prior to spinal surgery may not be introduced in the immediate future but older patients, smokers, those with more severe disability prior to surgery, obese patients, and those with darker skin may be considered at risk of inadequate vitamin D levels and tested prior to back surgery. Patients with conditions such as diabetes, depression, and autoimmune issues, including conditions like rheumatoid arthritis and lupus may also wish to have their vitamin D levels assessed as all of these have been connected with low levels of the nutrient and subsequent dysfunction of the immune system and neurological processes.
Sources of Vitamin D
Sun exposure is the main way in which people obtain sufficient vitamin D, and the body can store the synthesized nutrient for later use. However, where patients’ disabilities prevent them from spending much time outdoors, where little skin is exposed to the sun (such as in winter or where sunscreen is always used), or where a patient lives at a more northerly latitude where the strength of the sun is lower, supplements may be required for optimum intake. Darker skinned patients are also at risk even in sunny areas as the melanin in their skin absorbs the ultraviolet light needed for the conversion of the precursor to vitamin D to the active nutrient.
Vitamin D Supplements
Vitamin D is essential for proper calcium absorption and use and the Institute of Medicine has a current intake recommendation of 600IU per day. The vitamin is fat-soluble and so supplements contained in an oil suspension are thought more likely to be absorbed. Vegans and those abstaining from the consumption of animal products are at a higher risk of vitamin D deficiency as there are no good plant sources of the vitamin (small amounts may be derived from mushrooms, as well as from fortified foods). Adequate sunlight and synthetic supplements can help to make up the shortfall, but as most vitamin D supplements are derived from sheep fat, many patients consider these unsuitable and so struggle to find products containing vitamin D2 (cholecalciferol) rather than D2 (ergocalciferol). This study, and previous research on the importance of vitamin D may prompt patients scheduled for back surgery, particularly spinal fusion surgery to have their levels of vitamin D checked to ensure the best possible outcome and it may be that they find that their general health also improves if an inadequate level of vitamin D is corrected.
North American Spine Society (NASS) 26th Annual Meeting: Abstract 45. Presented November 3, 2011.