| Part One:Digital anatomical analysis of sacral ala-iliac screwObjective: By simulated the sacral ala-iliac(SAI)screw trajectory though the adult pelvic three-dimensional reconstruction models and measured a series of parameters,we obtained the positioning relationship between the insertion point and the posterior superior iliac spine and sacral foramen,the angle of screw placement,our study will provide a solid theoretical basis for clinical percutaneous minimally invasive screw placement.Methods: Sixty cases of normal adult pelvis were selected,aged from 19 to81 years old,with an average of 52.5 years old.Among them,32 were males and 28 were females.After scanning the pelvis by thin-slice spiral CT,mimics was used to reconstruct and simulate the ideal SAI screw trajectory.The transverse angle and sagittal angle of the screw,the distance between the insertion point and the posterior superior iliac spine,and the outer edge of the sacral foramen on the coronal plane were meared and the differences were analyzed.Results: All patients had an ideal SAI screw trajectory.There was no significant difference in the length,transverse angle and sagittal angle of S1 AI and S2 AI screw trajectory in both left and right contrast data.After combining the left and right data,the length of the trajectory of the S1 AI screw was 116.9±7.8mm for men and115.5±9.1mm for the female,The difference was not statistically significant.The length of the trajectory of S2 AI screws was 127.7±8.1mm for men and 124.4±6.8mm mm for women,the difference was statistically significant.The diameter of the SAI screw trajectory of 32 men was ?10mm,22 of the 28 women had the diameter of the screw trajectory ?10mm,and the diameter of the screw trajectory of 6 women was between8 mm and 10 mm.The diameter of the male was larger than that of the female,and the difference was statistically significant.The transverse angles of S1 AI screws averaged59.0±7.4 degrees for men and 59.1±5.2 degrees for women,and the difference was not statistically significant;the average sagittal angle of S1 AI screws was 59.9±9.1 degrees for men and 60.6+6.1 degrees for women,how ever,the difference was not statistically significant.the average transverse angle of S2 AI was 43.0±4.3 degrees for males and44.0±3.1 degrees for females,and the difference was not statistically significant;the average sagittal angle of S2 AI was 30.2±7.1 degrees for males and 31.0±6.1 degrees for females,and the difference was not statistically significant.The insertion point of the S1 AI screw was roughly in the upper medial direction of the posterior superior iliac spine,the insertion point of the S2 AI screw was roughly at the lower end of the medial posterior superior iliac spine.Conclusion: The adult pelvis has enough space to insert the SAI screw.The transverse angle and sagittal angle of the S1 AI screw are larger than those of the S2 AI screw.Clarifying the relative positional relationship of body surface projection between the insertion point of the SAI screw and the posterior superior iliac spine and the sacral foramen and the angle of SAI screw trajectory are beneficial to percutaneous minimally invasive screw placement.Part Two:Design of minimally invasive SAI screw lumbopelvic fixation systemIn order to meet the requirements of minimally invasive lumbopelvic fixation surgery,we have designed a lumbopelvic minimally invasive fixation system using a sacral ala-iliac screw with a guide hole.This system includeed a screw rod with a guide hole and a fixing cap,The fixed cap could be connected with the pedicle screw and rod fixation system.The study applied for a patent on the system and was authorized.The system does not require a wide range of incision during the operation.By cooperating with the Kirschner wire orientation,the installation and implantation of the SAI screw can be achieved by percutaneous minimally invasive,with less bleeding,less trauma,and quicker recovery.The system can be also used for implantion of INFIX.Part Three:Radiographic study of sacral ala-iliac screwObjective: To perform fluoroscopy in different phases of pelvic specimens with SAI screw guide pins and find the fluoroscopy phase,that is required for percutaneous minimally invasive placement of SAI screws.Method: 3 cases of pelvic specimens were placed in Kirschner wires according to the trajectory calculated in part one,and the C-arm X-ray machine was used to perform anteroposterior view,lateral view,inlet view,outlet view,iliac oblique view,obturator inlet view and obturator outlet view,saved the images and exported them for analysis.Results: the anteroposterior view,lateral view,inlet view,outlet view,iliac oblique view,obturator inlet view and obturator outlet views were obtained.Among them,the anteroposterior view,outlet view,iliac oblique view and obturator inlet view,obturator outlet views were important perspectives for judging the position of the SAI screw trajectory.Conclusion: The anteroposterior view,outlet view,iliac oblique view and obturator inlet view,obturator outlet views are important views in the process of percutaneous minimally invasive SAI screw placement.The accurate fluoroscopy of these views can improve the efficiency of surgery and reduce the failure rate of surgery.Part Four: Lumbopelvic fixation and Triangular Osteosynthesis using sacral ala-iliac screws for sacral fracturesObjective: Comparison of the clinical efficacy of SAI screw and iliac screw lumbopelvic fixation and triangular osteosynthesis in the treatment of sacral fractures.Methods: The data of patients with sacral fractures treated with lumbopelvic fixation and triangular osteosynthesis from December 2017 to June 2020 were retrospectively analyzed.The study group consisted of 12 patients with sacral fractures treated with sacral ala-iliac screw lumbopelvic fixation and triangular osteosynthesis in our department from December 2019 to June 2020,including 3 males and 9 females;the patients aged 13-52 years old,with an average age of 32.6±15.0 years;the control group included 30 patients with sacral fractures treated with iliac screw lumbopelvic fixation and triangular osteosynthesis from December 2017 to November 2019,including 18 males and 12 females;the patients aged 15-53 years old,with an average age of 35.8±12.5years old.Causes of injury: in the study group,there were 11 cases of fall injuries and 1case of traffic injuries;26 cases of fall injuries and 4 cases of traffic injuries in the control group.According to Tile classification of pelvic fractures,there were 4 cases of type C1,8cases of type C3 in the study group;8 cases of U-shaped sacral fracture cross section according to Roy-Camille and Strange-Vognsen classification:2 cases of type II,6 cases of type III,8 cases of U-shaped fractures with sacral nerve injury,Gibbons sacral nerve injury classification: 6 cases of grade 3,2 cases of grade 4.The remaining 4 cases were Isler B type,of which 2 cases were old fractures.According to Tile classification of pelvic fractures there were 9 cases of type C1,1 case of type C2,20 cases of type C3 in the control group;20 cases of U-shaped fractures were classified according to Roy-Camille and Strange-Vognsen type II in 4 cases,and type 3 in 15 cases.,1 case of type IV.20 cases of U-shaped fractures with sacral nerve injury,Gibbons sacral nerve injury classification: 14 cases of grade 3,6 cases of grade 4;of the remaining 10 cases,9cases of Isler classification were type B,1 case was type C,of which 3 cases were old fractures.The time from injury to operation in the study group was 6 to 32 days,with an average of 19.3±9.2 days.The time from injury to operation in the control group was 4 to30 days,with an average of 12.6±6.9 days.The operation was performed when the general condition permits.The study group underwent fracture resection and SAI screw lumbopelvic fixation or triangular osteosynthesis,and the control group underwent open reduction and iliac screw lumbopelvic fixation or triangular fixation.The patients with nerve injury underwent laminectomy decompression and sacral nerve root exploration decompression.The fixation of the anterior pelvic ring was determined by the injury.Regular follow-up reviews were performed after the operation.The operative time and intraoperative blood loss of the two groups of patients were collected,and the postoperative fracture reduction was evaluated according to the Matta standard.According to the Majeed scoring system and Gibbons sacral nerve injury classification at the last follow-up,the clinical function and neurological function were evaluated respectively.The occurrence of incision infection,screw protrusion discomfort,and lumbosacral discomfort were observed.Results: All patients were performed by the same surgeon and the same surgical team completed the operation.The operation process of all patients went smoothly.The average operative blood loss of the study group and the control group were(652.5±170.8)and(848.3±165.3)ml respectively,and the difference was statistically significant;the average operative time was(103.5±21.9)and(130.1±25.1)minutes,respectively.The difference was statistically significant.Group comparison of different fixation methods: The operation time of lumbopelvic fixation in the study group and the control group was(115.9±14.8)and(141.9±18.1)min,respectively,and the difference was statistically significant;Triangular osteosynthesis operation time of the study group and the control group were(78.7±4.8)and(106.6±20.6)min,respectively,and the difference was statistically significant;The blood loss during lumbopelvic fixation of the study group and the control group were(762.5±45.0)and(914.5±108.4)ml,respectively,and the difference was statistically significant;The blood loss during the triangular osteosynthesis in the study group and the control group was(432.5±73.7)and(716.0±184.5)ml,respectively,and the difference was statistically significant.Of the 12 cases in the study group,8 cases of U-shaped fractures were fixed with lumbopelvic fixation,of which 6 cases were fixed with transverse rods,and 2 cases of U-shaped fractures were not fixed with transverse fixation due to the absence of separation and displacement of the lower sacrum;the remaining 4 cases were fixed with triangular osteosynthes,transverse fixation in 3 cases with sacroiliac screws,and 1 case with sacral local plate.The anterior ring was fixed with steel plate in 4 cases,INFIX was used in 1 case,the pubic branch screw was fixed in 1 case,and the anterior ring was not fixed in 6 cases.Among the 30 cases in the control group,20 cases of U-shaped fractures used lumbopelvic fixation,of which 9 cases were fixed with transverse rods,6 cases were fixed with tension band plates,1 case was fixed with sacroiliac screw,and 1 case was fixed with a cross-linking rod combined with a local sacral plate,3 cases of U-shaped fractures were not fixed with transverse fixation due to the absence of separation and displacement of the lower sacrum;the remaining 10 cases were fixed by triangular osteosynthes,4 cases used sacroiliac screws for transverse fixation,1 case of sacral local plate,and 5 cases of tension band plate.The anterior ring was fixed with steel plates in 16 cases,Infix was used in 2 cases,the pubic branch screw was fixed in 2 cases,and the anterior ring was not fixed in 10 cases.All patients in the study group were followed up for 9 to 15 months,with an average follow-up of 10.3±1.7 months.All patients in the control group were followed up for 18 to 36 months,with an average follow-up of25.0±6.3 months.The postoperative reduction was evaluated according to Matta criteria.In the study group: 7 cases were excellent,4 cases were good,and 1 case was fair;the excellent and good rate was 91.7%.In the control group,20 cases were excellent,8cases were good,and 2 cases were fair.The excellent and good rate was 93.3%,and the difference was not statistically significant.At the last follow-up,the Majeed score was used to evaluate the clinical function of the patients.In the study group,6 cases were excellent,5 cases were good,and 1 case was fair,the excellent and good rate was 91.7%;in the control group,there were 20 excellent cases,7 good cases,and 3 fair cases;the excellent and good rate was 90%,the difference was not statistically significant.In the study group,8 U-shaped fractures had lower limb muscle strength before operation,and 2had rectal and bladder dysfunction,reaching grade 4.At the last follow-up,1 of 2 patients with rectal and bladder dysfunction recovered completely,and 1 case was found to have partial rupture of the nerve roots of the S1 and S2 during the operation,and the muscle strength below the calf was still weakened;Before the operation,6 cases of muscle weakness below the calf were significantly improved,4 cases were completely recovered,and 2 cases had residual lower limb sensory impairment;The Gibbons score increased by1.8±0.7 points on average(preoperative average 3.2 points,postoperative average 1.4points).In the control group,20 cases of U-shaped fractures all had lower limb muscle strength before operation,and 6 cases had rectal and bladder dysfunction,reaching grade4.At the last follow-up,2 of 6 patients with rectal and bladder dysfunction were found to have partial nerve root rupture during the operation,and the residual muscle strength below the calf was reduced;2 cases had sensory disturbance;2 cases recovered completely.The 14 patients with muscle weakness below the calf were significantly improved,10 patients recovered completely,and 4 patients had sensory impairment;Gibbons score increased by 1.8±0.6 points on average(preoperative average 3.3 points,postoperative average 1.5 points),there was no difference statistical significance.All patients underwent X-ray examination 3 to 6 months after the operation,and the fractures were healed without nonunion.During the postoperative follow-up,no incision complications were found in all patients in the study group,and 4 patients in the control group had incision infections,and the difference was not statistically significant.No discomfort of screw protrusion was found in the study group,and discomfort of screw protrusion was found in 12 cases in the control group;the difference was statistically significant.One patient in the study group had lumbosacral discomfort,and the control group had 3 cases of lumbosacral discomfort.The difference was not statistically significant.In the study group,1 case of S2 AI screw penetrated the outer plate of the iliac bone,and the patient had no obvious symptoms and was not treated.There was no screw penetration in the control group.All patients had no pelvic tilt and unequal length deformity of both lower limbs.At the last follow-up,all patients were not found any internal fractures or loss of reduction.Conclusion: Lumbopelvic fixation and triangular osteosynthesis using sacral ala-iliac screws for the treatment of sacral fractures are reliable,with less trauma,less complications,the clinical results is satisfactory. |
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