ObjectiveTo develop an instrument for sacroiliac joint fixation with less injury and less complications. MethodsFirstly, 18 adult pelvic specimens (8 males and 10 females) were used to measure the anatomical data related to the locking plates and locking screws on the sacrum and ilium, and the polyaxial locking plate screw system of the sacroiliac joint was designed according to the anatomic data. This system was made of medical titanium alloy. Then 4 adult male plevic specimens were harvested and the experiment was divided into 3 groups:group A (normal pelvic), group B (the dislocated sacroiliac joint fixed with sacroiliac screws), and group C (the dislocated sacroiliac joint fixed with polyaxial locking plate screw system). The vertical displacement of sacroiliac joint under the condition of 0-700 N vertical load and the horizontal displacement on angle under the condition of 0-12 N·m torsional load were compared among the 3 groups by using the biological material test system. Finally, the simulated application test was performed on 1 adult male cadaveric specimen to observe soft tissue injury and the position of the locking plate and screw by X-ray films. ResultsAccording to the anatomic data of the sacrum and ilium, the polyaxial locking plate screw system of the sacroiliac joint was designed. The biomechanical results showed that the vertical displacement of the sacroiliac joint under the condition of 0-700 N vertical load in group A was significantly bigger than that in group B and group C (P < 0.05), but there was no significant difference between group B and group C (P>0.05). The horizontal displacement on angle under the condition of 0-12 N·m torsional load in group A was significantly less than that in group B and group C (P < 0.05). The horizontal displacement on angle under the condition of 0-6 N·m torsional load in group B was bigger than that in group C, and the horizontal displacement on angle under the condition of 6-12 N·m torsional load in group B was less than that in group C, but there was no significant difference between group B and group C (P>0.05). The test of simulating application showed that the specimen suffered less soft tissue injury, and this instrument could be implanted precisely and safely. ConclusionThe polyaxial locking plate screw system of the sacroiliac joint has the advantages of smaller volume and less injury; polyaxial fixation enables flexible adjustment screw direction. The simulated application test shows satisfactory fixing effect.
ObjectiveTo assess the safety, feasibility, and effectiveness of medical calcium sulfate (OsteoSet) mixed with powder for injection of rifampicin after radical debridement in the treatment of sacroiliac joint tuberculosis. MethodsA retrospective analysis was made on the clinical data from 27 patients with sacroiliac joint tuberculosis who underwent debridement surgery and local bone graft of OsteoSet artificial bone impregnated with powder for injection of rifampicin between August 2006 and August 2010. There were 10 males and 17 females with an average age of 35.2 years (range, 16-64 years). The mean disease duration was 7.5 months (range, 1.5-16 months). The left sacroiliac joint was involved in 16 cases, the right side in 10 cases, and both sides in 1 case; Of them, 18 cases had iliac fossa abscess and 6 cases of buttocks abscess. According to the classification system by Kim, there were 9 cases of type Ⅲ and 18 cases of type ⅠV. The preoperative Majeed score was 61.23±6.49, including good in 4 patients, general in 19 patients, and poor in 4 patients. ResultsAll patients achieved wound healing by first intention; no complications of pelvic infection, peripheral nerve injury, and lower extremity deep vein thrombosis occurred. Twenty-six patients were followed up 16 months on average (range, 12-24 months). All the patients had normal sense and movement of both lower limbs; no perineum sensory disturbance was found. One case of multi-drug resistant had local recurrence at 3 months after operation, which was cured after adjusting anti-tuberculosis drugs, nutritional support, enhancing immunity with thymopentin, and second operation. Bone union was observed at 10.5 months on average (range, 9-12 months) in 25 patients, and clinical symptoms disappeared with no recurrence or complication, and they returned to previous work. The Majeed score at last follow-up was 92.31±3.36, showing significant difference when compared with preoperative score (t=-32.76, P=0.00). The results were excellent in 22 patients, good in 4 patients, and the excellent and good rate was 100%, showing significant follow-up was 92.31±3.36, showing significant difference when compared with preoperative score (t=-32.76, P=0.00). The results were excellent in 22 patients, good in 4 patients, and the excellent and good rate was 100%, showing significant difference compared with the preoperative one (χ2=31.93, P=0.00). ConclusionBone graft interbody fusion surgery with rifampicin loaded OsteoSet is one of the effective methods to treat sacroiliac joint tuberculosis.
ObjectiveTo explore the differences in the implantation safety and stability of a single the S1 alar-iliac screw (S1AIS) or S2AIS for sacroiliac joint fixation, providing reference for selecting appropriate internal fixation in clinical practice. MethodsPatients who underwent pelvic CT examination between January 2024 and December 2024 were selected. CT data from 80 patients with normal pelvic structure who met the selection criteria were included in a 1:1 male to female ratio. CT digital reconstruction technology was used to measure the transverse and longitudinal diameters of the S1AIS and S2AIS insertable ranges, as well as the length, width, and sacral side length of the screw trajectory. The pelvic CT data from 30 patients were randomly selected based on a 1:1 male to female ratio for three-dimensional (3D) printing of pelvic samples. The SAISs with a diameter of 6.5 mm and 8 mm were implanted at the optimal entry/exit points on the left and right sides, respectively, to observe the perforation of the screw trajectory. The pelvic CT data from 1 patient was randomly selected for 3D printing of 10 pelvic samples to simulate Tile C2 fracture. They were divided into S1AIS group and S2AIS group (n=5), with one S1AIS and one S2AIS fixation used for posterior sacroiliac joint separation, and the specimen stiffness and maximum load were measured by using an electric tension torsion dual axis universal mechanical tester. ResultsThe anatomical parameter measurement showed that there was no significant difference in the length and width of the screw trajectory between S1AIS and S2AIS (P>0.05), but the transverse and longitudinal diameters of the insertable ranges, as well as the sacral side length of the screw trajectory, were all greater than those of S2AIS, with significant differences (P<0.05). After simulating the implantation of S1AIS and S2AIS with a diameter of 6.5 mm in pelvic specimens, no screw penetration was observed. Both S1AIS and S2AIS with a diameter of 8.0 mm showed screw penetration, with S2AIS having a higher incidence of posterior lateral sacral cortical penetration (46.7%) than S1AIS (3.3%) (P<0.05). The biomechanical test showed that the stiffness and maximum load of S2AIS were significantly lower than those of S1AIS (P<0.05). ConclusionAs a method to fix the sacroiliac joint, a single S1AIS has a larger insertable range, a longer sacral side length of the screw trajectory, a lower incidence of posterior lateral cortical rupture of the sacrum, and a greater fixation strength than S2AIS. Therefore, the implantation safety and fixation stability of a single S1AIS are superior to S2AIS, and a diameter less than 8.0 mm screws should be selected as S2AIS for Chinese people.