Dear Editor-in-Chief We read with interest the article by Toopchizadeh et al. (1) reporting outcomes in pediatric patients with Sciatic nerve Injection injury (SNII) following gluteal injection. Despite the commendable efforts of the authors in long-term monitoring of outcomes in these select cohort of patients with SNII using appropriate electro-diagnostic studies, supplemented use of advanced imaging techniques such as Magnetic Resonance (MR) Neurography to note for structural changes, and diffusion tensor tractography (DTT) for functional altercation, if at all, would have been worth exploring, especially in a setting where the utility of the former in pediatric patients may be limited by poor tolerance (2).

Sciatic is the thickest nerve of the body with three quarter of an inch. It is forms from L4, L5, S1, S2 and S3 of spinal nerves as a part plexus in pelvis.It leaves the pelvis via great Sciatic foramen, and aises in gluteal region in infra piriformis fossa. Then passes between great trochanter and ischial tuberosity and arrives to the posterior surface of thigh. At the level of superior angle of pobliteal fossa, it divides into two common, proneal and tibial branches. Muscular injection in upper lateral part of gluteal region is performed within gluteus medius and minimus muscles. The former is carried out with a considerable distance to avoid any harm to Sciatic nerve. However this variation that includes two parts of Sciatic nerve passes throw the supra and infra piriformis fossa is an important one. The later variation induces proximity between nerve and injection site, particularly in neo natales, furthermore, recognition of such variation helps in identification of piriformin syndrome. This type of variation is regarded as one of the rarest type of variation, and has not between referred to in many anatomical dictionaries.

Regarding the importance of Sciatic nerve distribution in replacement of anal sphincter and Sciatic nerve block we decided to study this matter for the first time in Iran. In this way 100 cadavers (88% male and 12% female) were dissected and studied by loop microscope. The results shows that primarily, according to the first branch derived from Sciatic; there would be 4 main Groups. If this samples were rgarded according to the second branch of the nerve, then there would be 6 accessory groups added. So, in group A the first branch was related to proximal part of semimembranosus, in group B the branch was recorded as normal variations based on the above mentioned patterns.

Gluteal intramuscular injection in newborns and children is one of the most common causes of Sciatic palsy. Two factors are important to cause this palsy: kind of injection material and injection side. In this article we reported 28 cases of Sciatic palsy (complere or incomplete) after gluteal region injection of diclofenac during years of 1368 to 1380 referring to Imam Khomeini. hospital. Ten of these patients underwent surgical release that all of them got satisfactory results.

Background: Trauma is one of the causes of peripheral nerve injuries. Free radicals increase after tissue damages. Usually free radicals are scavenged and detoxified by antioxidants. In this study we assessed antioxidative role of NGAL (Neutrophil gelatinase associated lipocalin=Lipocalin2) molecule on crushed Sciatic nerves of rats.Materials and Methods: In this study 40 rat's Sciatic nerves were crushed and then at day 1 and 3 and week 1, 3, 5 after injury the Sciatic nerve of rats which suffering crushed were extracted. First of all total mRNA of samples was extracted and then cDNA was synthesized. The expression of NGAL gene was confirmed by using semiquantitative RT-PCR analysis. For immunohistochemistry analysis, the samples were fixed in praformaldehyde and cut in 20 micrometer slices by cryostat.Results: The results showed that the expression of lipocalin 2 was significantly higher in day 1, day 3 and week 1 in crushed Sciatic nerves in compare with the intact (non-injured) nerves (p<0.0001). Immunohistochemistry results also confirmed the protein expression of these genes.Conclusion: The Sciatic nerve injuries cause oxidative stress which followed by crush injury. In this research NGAL molecule showed maximum up-regulation in degeneration process after injury when oxidative stress have maximum peak. In this project for the first time we demonstrated the role of this molecule in degeneration and regeneration process of peripheral nerves and with more studies it may suggest as new complemental treatment.