Context. Gabapentin is reported to have an analgesic effect of reducing phantom-limb pain (PLP) in adult patients. There is no study on preoperative use of gabapentin in pediatric population in terms of PLP prevention. Objective. To determine whether gabapentin could be used as an adjuvant agent of opioid-based pain control to lower the rate of PLP in pediatric patients undergoing amputation for malignant bone tumors in observation period of 60 days postoperatively. Methods. Pediatric patients who were diagnosed with osteosarcoma or Ewing's sarcoma around the knee and underwent amputation from May 2013 to March 2016 were registered to this prospective double-blind randomized controlled trial. Four days before amputation, the patients were randomized to a study group receiving oral gabapentin, and a control group receiving oral placebo, both for 30 days. Pain intensity was recorded using the visual analog scale at different time points in all patients. PLP was assessed daily during their postoperative hospital stay and at the last follow-up visit 60 days after operation. Results. Of the 45 patients included in our study, 23 patients were randomized to gabapentin group and 22 to placebo group. There was no significant difference in preoperative baseline pain intensity between the two groups (P ¼ 0.12). The overall postoperative pain intensity in gabapentin group was significantly lower than that in placebo group (P < 0.05). The rate of PLP in gabapentin group was significantly lower than that in placebo group (43.48% vs. 77.27%, P ¼ 0.033) at the last follow-up visit. Conclusions. In pediatric patients, gabapentin shows the effect of preventing PLP and reducing postoperative pain intensity in acute period after amputation. Initiation of gabapentin therapy as an adjuvant to opioids before amputation is beneficial with no severe adverse effect.

Associations between inflammatory gene polymorphisms (TNF-α 308G/A, TNF-α 238G/A, TNF-β 252A/G, TGF-β1 29T/C, IL-6 174G/C and IL-10 1082A/G) and osteosarcoma (OS) risk remain unclear. We conducted a systematic search to retrieve studies that investigated associations between inflammatory gene polymorphisms and OS risk. Nine studies that met the inclusion criteria were finally recruited in this meta-analysis. Overall, there was a significant association between TNF-α 308G/A, IL-10 1082A/G and OS risk, while there was no significant association between TNF-α 238G/A, TNF-β 252A/G and IL-6 174G/C and OS risk. Our subgroup analysis showed a significant association between IL-6 174G/C and IL-10 1082A/G and OS risk in Asians, while no such significant correlation was observed with TNF-α 308G/A, TNF-α 238G/A, TNF-β 252A/G and TGF-β1 29T/C polymorphisms. In Caucasians, there was a significant association between TNF-α 238G/A and the decreased incidence of OS. In conclusion, inflammatory gene polymorphisms play a key role in the occurrence and progression of OS. IL-6 174G/C polymorphism was obviously associated with OS risk in Asians, while TNF-α 238G/A polymorphism seemed to be associated with the decreased susceptibility to OS in Caucasians as Altman and Bland test indicated. Although controversial results were observed between IL-10 1082A/G and OS risk in Asians and Caucasians, it is difficult to make a definite conclusion about the role of IL-10 1082A/G polymorphism in the etiology of OS because our Altman and Bland test showed no good evidence to support a different effect in Asians and Caucasians.