title: Answer to the Letter to the Editor of Gui-Tao Li et al. concerning: "A systematic review and meta-analysis of biological treatments targeting tumour necrosis factor α for sciatica" by Williams NH, Lewis R, Din NU, Matar HE, Fitzsimmons D, Phillips CJ, Sutton A, Burton K, Hendry M, Nafees S, Wilkinson C (2013) Eur Spine J; 22:1921-1935.
authors.affiliation: North Wales Centre for Primary Care Research, North Wales Clinical School, Bangor University, Gwenfro 4-8, Wrexham Technology Park, Wrexham, LL13 7YP, UK, nefyn.williams@bangor.ac.uk.
authors.forename: Nefyn H
authors.initials: NH
authors.lastname: Williams
authors.forename: Ruth
authors.initials: R
authors.lastname: Lewis
mesh_terms: D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D061067:Antibodies, Monoclonal, Humanized / Q000627:therapeutic use*; D006801:Humans; D007074:Immunoglobulin G / Q000627:therapeutic use*; D018124:Receptors, Tumor Necrosis Factor / Q000627:therapeutic use*; D012585:Sciatica / Q000188:drug therapy*; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors*
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D007074:Immunoglobulin G; D018124:Receptors, Tumor Necrosis Factor; D014409:Tumor Necrosis Factor-alpha