Influences of lateral, front-rear and rotational displacements on injury to sacral nerves in fractures of sacral zone II

Abstract

Objective To retrospectively analyze the associations of injury to the sacral nerves with lateral, front-rear and rotational displacements in fractures of sacral zone Ⅱ. Methods The data of 62 patients with fracture of sacral zone Ⅱ who had been treated in our hospital between January 2005 through December 2008 were collected using the PACS system and case reports checking system. There were 44 sides of compressed fracture, 15 of which had combined nerve injury while 29 did not. There were 24 sides of separated fracture, 8 of which had combined nerve injury while 16 did not. The groups with and without combined nerve injury in both compressed and separated fractures were compared in terms of the compression or separation distances as well as front-rear and rotational displacements. Results In compressed fractures, the average compression distance in the group with nerve injury (7. 43 ±2. 98 mm) was significantly longer than that in the group without nerve injury (4. 40 ± 3. 02 mm) ( t = 0. 162, P = 0. 003). There were significantly more front-rear and rotational displacements in the nerve injury group than in the other group ( P < 0. 05). In separated fractures, the average separation distance in the group with nerve injury (8. 24 ± 5. 51 mm) was similar to that in the group without nerve injury (6. 91 ± 2. 78 mm) (t = 0. 792, P = 0. 437). No statistical difference was found between the 2 groups in the front-rear displacement (P = 0. 667) but there were significantly more rotational displacements in the nerve injury group than in the other group ( P = 0. 021) . Conclusions The compression distance is associated with neurological deficit in fractures of sacral zone II. The fractures combined with front-rear and rotational displacements are more likely associated with nerve injury. The separation distance in separated fractures is not associated with neural damage. The separated fractures combined with rotational dislocation are more likely combined with neural injury. Key words: Sacum; Fractures, bone; Nerve; Injury