Identification of safe channels for screws in the anterior pelvic ring fixation system.

BACKGROUND: Minimally invasive surgery for pelvic fracture using anterior ring internal fixator system is increasing gradually, and the way to insert the fixation screws in the fixation system is the key technical points of the method. However, there have been few studies on insertion of fixation screws for the anterior pelvic ring internal fixator system. OBJECTIVE: To identify safe channels for fixation screws in the anterior pelvic fixator system and provide the anatomical basis for insertion of fixation screws in clinical operation. METHODS: Screw insertion was simulated into a total of 40 pelvic finite element models as well as 16 fresh pelvic specimens, and the channel parameters were measured. RESULTS: Finite elements (male, female) include: screws in ilium: length 114.4 ± 4.1 and 107.6 ± 8.3 mm, respectively; diameter 11.7 ± 0.5 and 10.0 ± 0.6 mm, distance between screw and anterior inferior iliac spine: 5.5 ± 1.0 and 5.6 ± 1.0 mm, angle of coronal plane 55.8° ± 2.4° and 50.6° ± 3.1°, angle of sagittal plane 26.6° ± 1.0° and 24.5° ± 1.9° and angle of horizontal plane 64.9 ± 3.7 and 58.1 ± 3.1; screws in pubis: length 47.0 ± 2.0 and 39.8 ± 3.9 mm, diameter 7.1 ± 0.4 and 6.1 ± 0.4 mm. Specimens (male, female) include: distance between screw and anterior inferior iliac spine: 5.5 ± 0.5 and 5.6 ± 0.7 mm, angle of coronal plane 55.9° ± 1.3° and 50.7° ± 1.5°, angle of sagittal plane 26.7° ± 0.5° and 24.1° ± 0.9° and angle of horizontal plane 64.8° ± 0.6° and 58.8° ± 0.8°. In the comparison between female and male in each group, differences in distances between screws and anterior inferior iliac spine and median line of symphysis pubis (P > 0.05) were not statistically significant; differences in the remaining parameters were statistically significant (P < 0.05). CONCLUSIONS: If surgeons paid attention to sex differences, select screws of appropriate diameter and length and hold the insertion position and direction, screws in the anterior pelvic ring fixation system could be safely inserted.

Clinical application of anterior ring internal fixator system combined with sacroiliac screw fixation in Tile C pelvic fracture treatment.

BACKGROUND: How to perform minimally invasive surgery for Tile C pelvic fracture is a major problem in clinical practice. We performed minimally invasive surgery for Tile C pelvic fracture using anterior ring internal fixator systems combined with sacroiliac screw fixation. OBJECTIVE: To investigate the advantages and efficacy of anterior ring internal fixator systems combined with sacroiliac screw fixation in the treatment of Tile C pelvic fracture. METHODS: From May 2017 to May 2020, 27 patients with Tile C pelvic fracture who underwent anterior ring internal fixator system combined with sacroiliac screw fixation (group A) and 21 patients with Tile C pelvic fracture who underwent plate-screw system combined with sacroiliac screw fixation (group B) were retrospectively analyzed. RESULTS: All 48 patients were followed up for more than 12 months, all fractures healed within 3-6 months. The operative time, intraoperative bleeding volume, blood transfusion volume, incision length, hospital stay, complication rate and Majeed score were 63.5 ± 10.7 min, 48.3 ± 27.9 ml, 0 ml, 4.5 ± 0.8 cm, 10.2 ± 2.7 d, 3.7% and 89.7 ± 4.6 points, respectively, in group A and 114.8 ± 19.1 min, 375 ± 315.8 ml, 266.7 ± 326.6 ml, 9.2 ± 3.9 cm, 20.9 ± 5.7 d, 23.8% and 88.7 ± 4.9 points, respectively, in group B. Combined excellent and good rates of the Matta evaluation and Majeed score were 100% in both groups. There were no significant differences in the Matta evaluation or Majeed score between the two groups (both P > 0.05), whereas the operative time, intraoperative bleeding volume, blood transfusion volume, incision length and hospital stay were significantly less in group A (all P < 0.05). CONCLUSION: An anterior ring internal fixator system combined with sacroiliac screw fixation can effectively treat Tile C pelvic fracture, and has advantages, including minimal invasiveness, simple operation, short operative time, safe and reliable features, fewer complications, short hospital stay and a good curative effect.

Biomechanical study of Tile C3 pelvic fracture fixation using an anterior internal system combined with sacroiliac screws.

BACKGROUND: How to perform minimally-invasive surgery on Tile C pelvic fractures is very difficult, and it is also a hot topic in orthopedic trauma research. We applied minimally-invasive treatment using an anterior internal fixator combined with sacroiliac screws. OBJECTIVES: To compare the biomechanical properties of different fixation models in pelvic facture specimens, using an internal fixation system or a steel plate combined with sacroiliac screws. METHODS: Sixteen fresh adult cadaver pelvic specimens were randomly separated into four groups named A, B, C, and D. The four groups were respectively stabilized using a two-screwed, three-screwed, or four-screwed anterior internal fixator or a steel plate with sacroiliac screws. All models were tested in both standing and sitting positions. Vertical loads of 600 N were applied increasingly. Shifts of bilateral sacroiliac joints and pubis rupture were measured. RESULTS: The shifts in sacroiliac joints and pubis rupture in the standing position were all less than 3.5 mm, and the shifts in the sitting position were all less than 1 mm. In the standing position, the results of shifts in the sacroiliac joints were group C < group D < group B < group A. For comparisons between A:B and C:D, P > 0.05. For comparisons between A, B:C, and D, P < 0.05. The results of shifts in pubis ruptures were group D < group C < group B < group A. In the comparison between C:D, P > 0.05; for comparisons between A:B, A:C, A:D, B:C, and B:D, P < 0.05. In the sitting posture, the results of shifts in the sacroiliac joints were group C < group D < group B < group A, and the shifts in the pubis ruptures were group D < group C < roup B < group A. For comparison between C:D, P > 0.05. For comparisons between A:B, A:C, A:D, B:C, and B:D, P < 0.05. CONCLUSION: Use of an anterior internal fixator combined with sacroiliac screws effectively stabilized Tile C3 pelvic fractures. The stability of specimens increased as the number of screws in the internal fixator increased.