The Effect of Bariatric Surgery on Peripheral Polyneuropathy: a Systematic Review and Meta-analysis. 
Neurological complications such as peripheral neuropathies are the most common complications among patients with morbid obesity following bariatric surgery.  Reduction in nutrient intake especially thiamin may develop polyneuropathy, while neuropathic symptoms improved in patients with diabetes independent of glycemic control after bariatric surgery.  The aim of the present review is to investigate the effect of bariatric surgery on peripheral neuropathy.  Electronic literature search was done via scientific search engines.  After the removal of duplicates and selection of articles of interest, 4 studies were included.  A random effects model was applied in this meta-analysis.  Considering the pooled analysis, bariatric surgery was significantly associated with Neuropathy Symptoms Score (NSS) (ES = - 3.393, 95% CI (- 4.507, - 2.278), and P value < 0.0001).  Reduction in NSS for patients with type 2 diabetes and BMI < 35 kg/m2 who were insulin-dependent was more than patients with morbid obesity without diabetes.  Furthermore, neuropathy disability score (NDS) significantly decreased in patients having bariatric surgery (ES = - 0.626, 95% CI (- 1.120, - 0.132), and P value < 0.013).  The NDS significantly decreased in patients with type 2 diabetes and BMI < 35 kg/m2 treated with insulin as well as patients with morbid obesity and type 2 diabetes.  In subgroup of patients with follow-up of more than 6 months after surgery, a significant reduction in NDS was detected while this reduction was not significant in patients with a follow-up of 6 months or less.  Bariatric surgery had a positive effect on peripheral neuropathy, though many studies showed neuropathy as one of the complications of bariatric surgery.