Effect of different lumbar-iliac fixation and sacral slope for Tile C1.3 pelvic fractures: a biomechanical study.

BACKGROUND: Lumbar-iliac fixation (LIF) is a common treatment for Tile C1.3 pelvic fractures, but different techniques, including L4-L5/L5 unilateral LIF (L4-L5/L5 ULIF), bilateral LIF (BLIF), and L4-L5/L5 triangular osteosynthesis (L4-L5/L5 TOS), still lack biomechanical evaluation. The sacral slope (SS) is key to the vertical shear of the sacrum but has not been investigated for its biomechanical role in lumbar-iliac fixation. The aim of this study is to evaluate the biomechanical effects of different LIF and SS on Tile C1.3 pelvic fracture under two-legged standing load in human cadavers. METHODS: Eight male fresh-frozen human lumbar-pelvic specimens were used in this study. Compressive force of 500 N was applied to the L4 vertebrae in the two-legged standing position of the pelvis. The Tile C1.3 pelvic fracture was prepared, and the posterior pelvic ring was fixed with L5 ULIF, L4-L5 ULIF, L5 TOS, L4-L5 TOS, and L4-L5 BLIF, respectively. Displacement and rotation of the anterior S1 foramen at 30° and 40° sacral slope (SS) were analyzed. RESULTS: The displacement of L4-L5/L5 TOS in the left-right and vertical direction, total displacement, and rotation in lateral bending decreased significantly, which is more pronounced at 40° SS. The difference in stability between L4-L5 and L5 ULIF was not significant. BLIF significantly limited left-right displacement. The ULIF vertical displacement at 40° SS was significantly higher than that at 30° SS. CONCLUSIONS: This study developed an in vitro two-legged standing pelvic model and demonstrated that TOS enhanced pelvic stability in the coronal plane and cephalad-caudal direction, and BLIF enhanced stability in the left-right direction. L4-L5 ULIF did not further improve the immediate stability, whereas TOS is required to increase the vertical stability at greater SS.

Anterior peri-sacroiliac joint osteotomy in the treatment of malunion and nonunion of complex pelvic ring fracture: techniques and preliminary results.

PURPOSE: To introduce anterior peri-sacroiliac joint osteotomy (APSJO) through the lateral-rectus approach (LRA) for treating pelvic fracture malunion and nonunion, and to evaluate the safety, feasibility, and potential effectiveness. METHODS: Data of 15 patients with pelvic fracture malunion and nonunion who underwent treatment by APSJO were selected and analyzed. The reduction quality was assessed using the Mears and Velyvis criteria, while the pre-operative and post-operative function was revealed by the Majeed scoring system. The British Medical Research Council (BMRC) grading system was recruited for the evaluation of lumbosacral plexus function. RESULTS: The average operative duration was 264.00 ± 86.75 min, while the intra-operative blood loss was 2000 (600, 3000) mL. Anatomical reduction was complete in three cases, satisfactory in ten cases, and unsatisfactory in two cases. Among the seven patients with lumbosacral plexus injury, the pre-operative Majeed grades were good in two cases, fair in two cases, and poor in three cases, while the post-operative Majeed grades were excellent in three cases, good in three cases, and fair in one case. Muscle strength recovered to M5 in two cases, M4 in three cases, and showed no recovery in two cases. The pre-operative Majeed grades were good in five cases, fair in two cases, and poor in one case of the series without lumbosacral plexus injury, while the post-operative Majeed grades were excellent in seven cases and good in one case. CONCLUSION: APSJO through LRA may be a feasible strategy for treating pelvic fracture malunion and nonunion with promising application.

Design and Application of an Acetabular Integrative Anatomic Plate: A Retrospective Study of 178 Cases with Complex Acetabular Fractures.

OBJECTIVE: As conventional plates require repeated pre-bending during surgery with poor matching, this study aimed to explore the design and application of an acetabular integrative anatomical plate (AIAP) via the lateral-rectus approach (LRA) in fresh complex acetabular fractures for the good reduction and fixation. METHODS: We designed an AIAP based on the anatomical morphology of the Chinese people. From March 2016 to September 2021, 178 patients with fresh complex acetabular fractures treated with an AIAP via the LRA were retrospectively analyzed. All patients were treated by the LRA under general anesthesia in a supine position. The fragments were well reduced and fixed by AIAPs. The operation time and intraoperative blood loss were recorded. All patients underwent reexamination of pelvic X-rays and CT scans and were followed up for over 1 year postoperatively. The reduction quality of fracture was evaluated according to the Matta criteria. The postoperative functional recovery was evaluated by modified Merle d'Aubigne-Postel scoring system. Statistics were analyzed by SPSS 25.0 (SPSS Inc., Chicago, IL, USA). RESULTS: All 178 patients went through the operation successfully. The time from injury to operation ranged from 5 to 21 days (8.7 ± 2.6 days). The operation time ranged from 35 to 150 min (75 ± 29 min). The intraoperative blood loss was from 250 to 1400 ml (440 ± 153 ml). According to the Matta score, the fracture reduction was evaluated as excellent in 131 cases, good in 31 cases, and poor in 16 cases, with an overall excellent and good rate of 91%. Four patients suffered wound fat liquefaction and healed after fresh dressing. All patients were followed up for 1 to 5 years without wound infection. All fractures were healed. At the last follow-up, the modified Merle d'Aubigne-Postel score results were evaluated as excellent in 125 cases, good in 26 cases, and fair in 27 cases, with an overall excellent and good rate of 84.8%. Postoperative complications included six cases of traumatic arthritis of the hips and two cases of femoral head necrosis. CONCLUSION: The LRA with an AIAP can help expose, reduce, and fix anterior and posterior columns as well as the quadrilateral area of the acetabulum, which is capable of improving the reduction quality of complex acetabular fractures and shortening surgical time and blood loss, thus reaching a good clinical efficacy.

Treatment of Anterior Dislocation of the Sacroiliac Joint via the Lateral-rectus Approach: Surgical Techniques and Preliminary Outcomes.

OBJECTIVE: Anterior dislocation of the sacroiliac joint (ADSIJ) is caused by strong violence, and because of its low morbidity, there are no standardized diagnostic and therapeutical guidelines at this moment. This study aims to explore the surgical techniques and preliminary outcomes of the lateral-rectus approach (LRA) for treating ADSIJ. METHODS: A retrospective study was conducted of 15 patients with ADSIJ from January 2016 to January 2021. The patients' age ranged from 1.8 years old to 57 years old (37 ± 18 years old). All patients underwent open reduction and internal fixation (ORIF) through the LRA. Eight patients were combined with lumbosacral plexus injury and underwent neurolysis during operation. Patients' fracture type, mechanism of injury, associated injuries, operation time and intraoperative bleeding volume were accessed by reviewing medical history. Quality of fracture reduction was evaluated with the Matta score. At 1-year follow-up, the functional rehabilitation was evaluated by the Majeed rehabilitation criteria. For those with lumbosacral plexus injury, the neuromotor function was evaluated using muscle strength grading proposed by the British Medical Research Council (BMRC) and recovery was recorded. RESULTS: All 15 patients underwent the operation successfully. The surgical time ranged from 70 to 220 min (126 ± 42 min), and the intraoperative blood loss ranged from 180 to 2000 mL (816 ± 560 mL). Eighty percent of the cohort (12/15) were rated as excellent and good in the Matta score for fracture reduction quality after operation without surgical incision-related complications. At 1-year follow-up, the overall excellent and good rate was 73.3% (11/15) according to the Majeed criteria, the neuromotor function recovered completely in six cases and partially in two cases according to the BMRC muscle strength grading, and the recovery of sensory function was evaluated as excellent in six cases, good in one case and poor in one case, with an overall excellent and good rate of 87.5%. CONCLUSION: The LRA can well expose the surrounding structures of the sacroiliac joint from the front, which helps surgeons reduce and fix the anterior dislocation of the sacroiliac joint under direct vision and effectively decompress the entrapment of the lumbosacral plexus to achieve better clinical efficacy.

Posterior wall fractures of the acetabulum: treatment using an anatomical plate through direct posterior approach.

OBJECTIVES: This study was aimed to measure the application of W-shaped acetabular angular plate (WAAP) through direct posterior approach (DPA) on the reconstruction of acetabular posterior wall fractures when compared with reconstruction plates. PATIENTS AND METHODS: A retrospective study was performed on patients treated with the WAAP or reconstruction plates via the DPA. The intraoperative data of operative time, blood loss and radiation exposure times were recorded. Radiographs of the pelvis and CT scan were obtained within one week post-operation to assess the reduction quality. The clinical outcome was evaluated by the modified Merle d'Aubigne and Postel score. RESULTS: From May 2016 to October 2019, a total of 41 patients with simple acetabular posterior wall fractures were included in this study, 22 from the WAAP group and 19 from the reconstruction plates group. There were no significant differences between the two group in age, gender, time from injury to operation, cause of injuries, length of incision and follow-up time (P > 0.05). In comparison with the reconstruction plates group, the average operation time of the WAAP group was significantly shorter (46.1 ± 12.7 min vs 59.2 ± 17.4 min, P < 0.05), the average radiation exposure times were significantly less (2.3 ± 0.6 vs 3.6 ± 1.0, P < 0.001), the average blood loss was significantly less (240 ± 98.9 ml vs 301.1 ± 66.6 ml, P < 0.05). According to Matta radiology criteria and the modified Merle d' Aubigne and Postel score, no significant difference was observed between the two group, as for the quality of reduction and function outcomes. CONCLUSION: The application of WAAP through DPA showed satisfactory preliminary clinical outcomes, showing promise to be an alternative technique for the treatment of acetabular posterior wall fractures.

DEPTOR exacerbates bone-fat imbalance in osteoporosis by transcriptionally modulating BMSC differentiation.

Bone marrow-derived mesenchymal stem cells (BMSCs) tend to differentiate into adipocytes rather than osteoblasts in osteoporosis and other pathological conditions. Understanding the mechanisms underlying the adipo-osteogenic imbalance greatly contributes to the ability to induce specific MSC differentiation for clinical applications. This study aimed to explore whether DEP-domain containing mTOR-interacting protein (DEPTOR) regulated MSC fate and bone-fat switch, which was indicated to be a key player in bone homeostasis. We found that DEPTOR expression decreased during the osteogenesis of BMSCs but increased during adipogenesis and the shift of cell lineage commitment of BMSCs to adipocytes in mice with osteoporosis. DEPTOR facilitated adipogenic differentiation while preventing the osteogenic differentiation of BMSCs. Deptor ablation in BMSCs alleviated bone loss and reduced marrow fat accumulation in mice with osteoporosis. Mechanistically, DEPTOR binds transcriptional coactivator with a PDZ-binding motif (TAZ) and inhibits its transactivation properties, thereby repressing the transcriptional activity of RUNX2 and elevating gene transcription by peroxisome-proliferator-activated receptor-gamma. TAZ knockdown in BMSCs abolished the beneficial role of Deptor ablation in bone-fat balance in mice. Together, our data indicate that DEPTOR is a molecular rheostat that modulates BMSC differentiation and bone-fat balance, and may represent a potential therapeutic target for age-related bone loss.

A Single Lateral Rectus Abdominis Approach for the Surgical Treatment of Complicated Acetabular Fractures: A Clinical Evaluation Study of 59 Patients.

BACKGROUND This study aimed to evaluate outcome following a single lateral rectus abdominis surgical approach for complicated acetabular fractures, involving anterior and posterior columns. MATERIAL AND METHODS From January 2012 to March 2016, 59 patients, including 36 anterior column hemitransverse fractures, 18 two-column fractures, and five T-type complicated acetabular fractures, were treated with a single lateral rectus abdominis approach and fixed by plates and cannulated lag screws. Anterior column fractures were fixed with 3.5 mm reconstruction plates; posterior column fractures were fixed with 6.5 mm cannulated lag screws. The quality of surgical reduction (using the Matta criteria), functional outcome (using the modified Merle d'Aubigné and Postel scoring system), and postoperative complications were assessed with 24-month follow-up. RESULTS Fifty-nine patients (mean age, 45 years; range, 18-64 years) including 39 men and 20 women underwent surgery. Mean intraoperative blood loss was 514.6 ml (range, 150-830 ml) and mean operating time was 86.3 min (range, 42-145 min). Anatomical reduction was good in 40 cases (67.8%), fair in 15 cases (25.4%), and poor in four cases (6.8%). The modified Merle d'Aubigné score was excellent in 39 cases (66.1%), good in 14 cases (23.7%), fair in five cases (8.5%), and poor in one case (1.7%). At follow-up, there were five cases of peritoneal damage, eight cases of obturator nerve dysfunction, and four cases of postoperative traumatic arthritis. CONCLUSIONS The single lateral rectus abdominis surgical approach for the treatment of complicated acetabular fractures was minimally invasive with good anatomical exposure and good outcomes.

[Pararectus approach for treatment of acetabular both-column fracture combined with translocation of quadrilateral surface].

OBJECTIVE: To study the clinical effect and surgical operating points of pararectus approach for the internal fixation of acetabular both-column fractures with concurrent displaced quadrilateral plate fractures. METHODS: From January 2012 to December 2013, in the Third Affiliated Hospital of Southern Medical University, 15 patients with acetabular both-column fractures and displaced quadrilateral plate fractures were surgically managed through the pararectus approach. There were 11 male and 4 female patients, with an average age of 40 years (from 19 to 61 years). According to Judet-Letournel classification, there were 9 anterior column plus posterior hemitransverse fractures, 6 both-column fractures, 8 cases involving the pelvic fracture. All these fractures were treated through the pararectus approach, in the horizontal position with general anesthesia. The pre-bended plate was placed in interior pelvic ring to fix the anterior wall, anterior column and quadrilateral plate in direct sight. Then, the posterior column was exposed and fixed with antegrade lag screw. Patients were followed up in 4 weeks, 12 weeks, 6 months, 1 year after the operation, and the anteroposterior radiograph of pelvis and the X-ray examination of the fractured hip was performed. RESULTS: All the 15 cases underwent the operation successfully. Postoperative X-ray and CT exams showed excellent and good reduction of anterior column, posterior column and quadrilateral plate, with none surgical complication occurred. According to the Matta radiological evaluation postoperatively, reduction of acetabular fracture was rated as excellent in 9 cases, good in 3 cases and poor in 3 cases. The rate of excellent and good was 12/15. After 8 to 18 months' follow-up (median follow-up time was 14 months), all the patients gained bone union. According to the modified Merle D'Aubigne and Postel scoring system, 9 cases were excellent, 4 were good, and 2 were fair. The rate of excellent and good was 13/15. CONCLUSIONS: Surgical management of acetabular fractures through the pararectus approach can provide adequate exposure of reducing and fixing both-column acetabular fractures with concurrent displaced quadrilateral plate fractures, which has a good effect in clinical application.

[Establishment of a rabbit model of lumbar intervertebral disc degeneration via the paraspinal approach].

OBJECTIVE: To establish a rabbit model of intervertebral disc degeneration by puncturing the anulus fibrosus through an approach between the longissimus dorsi muscle and obliquus externus abdominis. METHODS: The L(4/5) and L(5/6) intervetebral discs of 6 New Zealand white rabbits were punctured by an 18-gauge pin in the anterolateral annular fibrosus through an approach between the longissimus dorsi muscle and the obliquus externus abdominis with the right transverse processes of L(5) and L(6) resected; the L(2/3) discs were used as the control without exposure or needle stab, and the L(3/4) discs were subjected to sham operation with the discs exposed but not punctured after resecting the right transverse process of L(4). X-ray and magnetic resonance imaging (MRI) were performed preoperatively and at the 4th week after puncture. At 4 weeks after the operation, histological and immunohistochemical analyses of the discs were carried out. RESULTS: X-ray of the punctured discs at 4 weeks after the operation presented a significant decrease of disc height, osteophytosis formation, and end-plate stiffness; an obvious decrease of signal intensity on T(2)-weighted images was found in the puncture group but not in the control or sham-operated groups. Gross morphological inspection showed atrophy of the nucleus pulposus, which became loose, soft, and fragile with a light yellow color. Histological and immunohistochemical analyses showed a significant decrease of notochordal cells and type II collagen in the nucleus pulposus in the puncture group as compared to the control and sham-operated groups. CONCLUSION: Puncture through the approach between the longissimus dorsi muscle and the obliquus externus abdominis allows the establishment of a reliable animal model for studying intervertebral disc degeneration.

Metformin stimulates osteoprotegerin and reduces RANKL expression in osteoblasts and ovariectomized rats.

Anti-diabetic drug metformin has been shown to enhance osteoblasts differentiation and inhibit osteoclast differentiation in vitro and prevent bone loss in ovariectomized (OVX) rats. But the mechanisms through which metformin regulates osteoclastogensis are not known. Osteoprotegerin (OPG) and receptor activator of nuclear factor κB ligand (RANKL) are cytokines predominantly secreted by osteoblasts and play critical roles in the differentiation and function of osteoclasts. In this study, we demonstrated that metformin dose-dependently stimulated OPG and reduced RANKL mRNA and protein expression in mouse calvarial osteoblasts and osteoblastic cell line MC3T3-E1. Inhibition of AMP-activated protein kinase (AMPK) and CaM kinase kinase (CaMKK), two targets of metformin, suppressed endogenous and metformin-induced OPG secretion in osteoblasts. Moreover, supernatant of osteoblasts treated with metformin reduced formation of tartrate resistant acid phosphatase (TRAP)-positive multi-nucleated cells in Raw264.7 cells. Most importantly, metformin significantly increased total body bone mineral density, prevented bone loss and decreased TRAP-positive cells in OVX rats proximal tibiae, accompanied with an increase of OPG and decrease of RANKL expression. These in vivo and in vitro studies suggest that metformin reduces RANKL and stimulates OPG expression in osteoblasts, further inhibits osteoclast differentiation and prevents bone loss in OVX rats.

Inhibition of mTOR signaling by oleanolic acid contributes to its anti-tumor activity in osteosarcoma cells.

Oleanolic acid (OA), a pentacyclic triterpenoid exhibits potent anti-tumor activity against many tumor cell lines. But the mechanisms through which OA inhibits osteosarcoma cells are not known. The mammalian target of rapamycin (mTOR) serves as a central regulator of cell growth, proliferation, survival, and metabolism by integrating intracellular and extracellular signals. In this study, we examined effects of OA on proliferation, cell cycle progression, apoptosis in osteosarcoma cells, and involvement of mTOR signaling in this process. OA inhibited cell proliferation and colony formation, induced G1 arrest in osteosarcoma MG63 and Saos-2 cells dose and time dependently. The protein level of cyclin D1, which plays critical role in G1 to S phase transition and servers as a downstream target of mTOR complex 1 (mTORC1) was down-regulated by OA. Phosphorylation of p70 ribosomal S6 kinase 1 (p70 S6K1) (T389) and S6 (S235/236), mediators of mTORC1 signaling in controlling protein translation and cell growth, was also inhibited by OA. Furthermore, OA inhibited phosphorylation of Akt, a pro-survival factor and substrate for mTORC2. Inactivation of Akt correlated with pro-apoptotic role of OA in osteosarcoma cells, as manifested by an increase in annexin V-FITC binding, cleavage of poly (ADP-ribose) polymerase (PARP) and activation of caspases 3. Our results suggest that OA is a promising agent for treatment of osteosarcoma and mTOR signaling may contribute to its anti-tumor effects on osteosarcoma cells.