Fixation with S 2 alar iliac screws for unstable injury to posterior pelvic ring / 中华创伤骨科杂志

Objective:To explore the fixation with S 2 alar iliac screws (S 2AI) for unstable injury to the pelvic posterior ring. Methods:The clinical data of 18 patients were analyzed retrospectively who had been treated for unstable injury to the posterior pelvic ring by S 2AI screw fixation at Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University and at Department of Orthopaedics and Traumatology, The First Affiliated Hospital to University of South China from September 2017 to December 2020. They were 8 males and 10 females, with an average age of 40 years (from 20 to 64 years). According to Tile classification, there were 3 cases of type B2, 10 cases of type C1 and 5 cases of type C2. Sacral nerve injury was complicated in 3 patients (2 cases of Gibbons grade Ⅱ and one of Gibbons grade Ⅲ). Short-segment S 1-S 2AI fixation was used in 6 cases, contralateral S 1-S 2AI fixation in one case, lumbar-pelvic fixation in 5 cases, and sacroiliac triangle fixation in 6 cases. The accuracy of S 2AI placement was evaluated by CT after operation according to the Shillingford method; the reduction quality of pelvic fractures and complications were documented. Results:All the 18 patients were followed up for 19.8 months (from 12 to 36 months). Bony union was achieved in all fractures. A total of 21 S 2AI were implanted in the 18 patients without intraoperative neurovascular injury. Postoperative CT found penetration into the iliac cortex by S 2AI in 2 cases. According to the Matta criteria, the fracture reduction was excellent in 10 cases, good in 7 and fair in one. Of the 3 patients with preoperative sacral nerve injury, 2 with grade Ⅱ injury recovered to grade Ⅰ and one with grade Ⅲ injury recovered to grade Ⅱ after operation. Superficial infection occurred at the incision site in 2 patients after operation, and complications such as protrusion, rupture or loosening of implants were observed in none of the patients. Conclusion:S 2AI fixation can be flexibly applied to various types of posterior pelvic ring injury and can provide the pelvic ring and the lumbosacral junction with rigid fixation, leading to a low complication rate.

Osteoporotic Compression Fracture of the Thoracolumbar Spine and Sacral Insufficiency Fracture: Incidence and Analysis of the Relationship according to the Clinical Factors

PURPOSE: To evaluate the incidence of sacral insufficiency fracture in osteoporotic patients with compression fracture of the thoracolumbar (T-L) spine on magnetic resonance image (MRI), and to analyze the correlation of variable clinical factors and the incidence of sacral insufficiency fracture. MATERIALS AND METHODS: We retrospectively reviewed 160 patients (27 men, 133 women; age range of 50 to 89 years) who underwent spinal MRI and had compression fracture of the T-L spine. Compression fractures due to trauma or tumor were excluded. We evaluated the incidence of sacral insufficiency fracture according to the patients' age, sex, number of compression fractures, and the existence of bone marrow edema pattern of compression fracture. During the same period, we evaluated the incidence of spinal compression fracture in the patients of pelvic insufficiency fracture. RESULTS: Out of the 160 patients who had compression fracture in the T-L spine, 17 (10.6%) had insufficiency fracture of the sacrum. Compression fracture occurred almost 5 times more frequently in women (27:133), but the incidence of sacral insufficiency fracture was 2/27 for men (7.4%) and 15/133 for women (11.3%), with no statistically significant difference (p = 0.80). According to age, the ratio of insufficiency fracture to compression fracture was 0% (0/23) in the 50's, 10.6% (7/66) in the 60's, 12.5% (7/56) in the 70's, and 20.0% (3/15) in the 80's. In respect of single and multiple compression fracture, the incidence of sacral insufficiency fracture was 8/65 for men (12.3%) and 9/95 for women (9.5%), showing no significant difference (p=0.37). In the patients with and without compression fracture with bone marrow edema, insufficiency fracture occurred in 5/76 (6.6%) and 12/84 (14.3%), respectively. On the other hand, of the 67 patients who had pelvic insufficiency fracture, 27 (40.3%) also had spinal compression fracture. CONCLUSION: About 10% of the patients with osteoporotic compression fracture in the T/L spine also had pelvic sacral insufficiency fracture, which was not uncommon. These findings suggest the need to consider the possibility of pelvic sacral insufficiency fracture in cases of T/L spinal MRI for patients with osteoporotic compression fracture.

MR Findings of Sacral Insufficiency Fractures in Osteoporotic Patients: Two Cases Report

Osteoporosis is one of the major causes of insufficiency fractures, and since plain radiographic findings are either unhelpful or misleading, insufficiency fracture in the sacrum is particularly difficult to diagnosis and to differentiate from other disease processes such as metastasis. We report the MR findings of two cases of insufficiency fracture of the sacrum. These were not demonstrable on conventional radiographs, but bone scintigraphy revealed unilateral sacral alar uptake, suggesting an active sacral lesion. Both T1 and T2-weighted MR images demonstrated fractures of the sacrum as bands of low signal intensity, with areas of surrounding increased signal intensity seen on the latter suggesting marrow edema.