[Risk factors affecting fusion in the treatment of lumbar spine instability].

Background: Risk factors are the endogenous or exogenous factors that may be controlled and they are responsible for disease. The objective of this paper is to describe the risk factors affecting vertebral fusion in patients with lumbar spine instability seen at our hospital and to see how they relate to nutritional factors.
Material and Methods: Patients undergoing vertebral fusion due to several diagnoses were analyzed. Different parameters were captured to determine the interaction among them and assess the factors affecting vertebral fusion healing. They were compared with patients with pseudoarthrosis to determine its risk factors. Patients were divided into two groups: the control group, who underwent fusion, and the cases, who had pseudoarthrosis.
Results: A total of 59 patients were examined; 15 (25.4%) were cases (pseudoarthrosis) and 44 (74.6%) were controls (fusion). The demographic distribution was 27 (45.8%) females and 32 (54.2%) males; mean age was 51 +/- 12 years, with a minimum age of 20 and a maximum of 85. The diagnostic-based distribution was as follows: 29 (49.1%) spondylolistheses, 21 (35.6%) fractures, 5 (8.5%) herniated discs, 3 (5.1%) infections, and one (1.7%) tumor. Mean body weight was 75.9 kg, height was 160 cm, BMI 24.5, Hb 15.2, Hct 35.9, and Alb 3.5. Various risk factors were analyzed including the following: age over 60 years, which showed a 49% higher chance of pseudoarthrosis compared with the control group, with a 95% CI, 0.12-2.27; body weight over 90 kg, which showed an 82% higher chance of pseudoarthrosis compared with the fusion group, with a 95% CI, 0.03-0.43; BMI, which showed a 25% higher chance of pseudoarthrosis, with a 95% CI, 0.18-3.18; hypoalbuminemia < 3.4 mg/100 ml, which showed a 78% higher chance of pseudoarthrosis, with a 95% CI, 0.06-0.75.
Conclusions: This study found that pseudoarthrosis is caused by risk factors linked to the nutritional profile, i.e., obesity, and hypoalbuminemia; its chance of occurring is 1.5 greater than in individuals with normal values. For this reason it is important to assess these values and correct them early on during the preoperative period with supportive measures allowing for an appropriate metabolic control and the consequent optimum result, i.e., fusion.