The clinical value analysis of MRN on diagnosis and treatment of lumbosacral nerve injury associated with sacral fractures / 中华骨科杂志

ABSTRACT

Objective:To discuss the clinical value of magnetic resonance neurography (MRN) on diagnosis and treatment of lumbosacral nerve injury associated with sacral fractures and analyze the characters of nerve injury which was caused by sacral fractures.Methods:The clinical data of 40 patients who had lumbosacral nerve injury associated with sacral fractures and accepted treatment in Tianjin hospital from August 2018 to December 2020 were collected based on inclusion and exclusion criteria. Twenty-four patients had unilateral sacral fractures (Tile C1) which included 16 Denis II type fractures and 8 Denis III type fractures. Sixteen patients had bilateral sacral fractures which were all Tile C3, U shaped and Denis II type sacral fractures. All patients had symptoms or signs of lumbosacral nerve injury, and accepted contrast-enhanced three-dimensional magnetic resonance neurography (CE-3D MRN) to diagnose the injury part and severity degree. The L 5-S 4 nerves were separated to three parts based on injured side and intraspinal type (IS), intraforaminal type (IF) and extraforaminal type (EF) location, and were judged the mild, medium or severe degree of nerve injury severity. Overall and pairwise Chi-square test was performed on the number of nerve injuries. Eleven patients accepted the operation of nerve dissection and exploration. The nerve injury part and severity were recorded under direct vision, and were statistically analyzed with CE-3D MRN outcome. Results:The outcome of 239 lumbosacral nerve injuries which had different part and severity were found by MRN, and all combined with sacral fractures of the same side. The nerves which ranked from largest to fewest according to injured numbers were L 5, S 1, S 2, S 3 and S 4. The statistical analysis showed that there were significant differences of injured nerve numbers except between S 1 and S 2, S 3 and S 4, and there were no significant difference of nerve injury part and severity degree between the direct visual judgement intraoperatively and preoperative CE-3D MRN examination. Conclusion:MRN can reveal the part and severity degree of lumbosacral nerve injury associated with sacral fracture clearly and accurately, which has important clinical value and should become the preferred examination of such injuries. The lumbosacral nerve injury has the most frequent features of S 1 and S 2, followed by L 5, and the least in S 3 and S 4.