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find Keyword "screw" 238 results
  • VERTEBRAL PEDICLE SCREW-RODS SYSTEM FOR CORRECTING PARALYTICSCOLIOSIS

    Objective To explore some operative problems of correcting paralytic scoliosis(PS) by using vertebral pedicle screwsrods system. Methods From May 2000 to May 2005, 18 patients with PS were corrected by screwsrods system which were made of titanium alloy.There were 10 males and 8 females, aging from 11 to 26 years. The primary disease included poliomyelitis in 13 patients and myelodysplasia (MS) in 5 patients (2 cases for second correction) with scoliosis of an average 85° Cobb angle (55-125°). The pelvic obliquity was found in all patients with an average 24° angle (355°).Of the 18 patients,3 cases were given perioperative halo-pelvic traction, 2 cases were given vertebral wedge osteotomy and correction and fixation, the other patients were purely underwent the treatment of pedicle screwrods system implants. Fusion segment at operation ranged from 6 to 15 sections, applied screws the most was 16,the fewest was 6. Results There were no wound infections and neurologic complications, all wounds healed by the first intention. Allscoliosis obtained obvious correction (P<0.001), the correction rate averaged 52.95% (44%-81%); the majority of lumbar kyphosis and pelvic obliquity were apparently corrected. The average clinical follow-up (16 cases) was 21 months(6-36 months),there was no implants failure. One patient with MS had a worse Cobb magnitude, the other patients had no curve progression (P>0.05). Conclusion The use of vertebral pedicle screwsrods fixation to multiple vertebral bodys and short segment fusion for PS, the treatment method is reliable and the outcome is satisfactory. While performing the correcting operative procedures, the spinal, pelvic and lower extremity deformities and functions should be all considered as a whole.

    Release date:2016-09-01 09:19 Export PDF Favorites Scan
  • BIOMECHANICAL RESEARCH ON INTERNAL FIXATION METHODS OF POSTERIOR PELVIC RING FRACTURE DISLOCATION

    Objective To investigate the biomechanical differences of three internal fixation approaches, namely improved Galveston (IG), reconstruction plate (RP), and il iosacral screw (LS) to the posterior pelvic ring fracture dislocation and provide experimental evidence for the cl inical appl ication of proper internal fixation method. Methods Six donatedfresh adult cadaver pelvic specimens (age averaged 45 years old) were numbered randomly and their normal biomechanics were tested by the measure instrument (MTS855 Mini-Blonix). The displacement values of normal pelvis were measured under the vertical compression (800 N) and reverse direction compression (8 N·m). Then they were made into left Denis I pelvic fracture and fixed with the IG, RP, and LS, respectively, in different orders. Biomechanics test was conducted on the fixed pelvis from both the vertical and the reversed directions. Results Concerning the direction of vertical ity and torsion, the order of fracture displacement from small to large was the normal pelvis, LS, IG and RP. There was no significant difference between LS and the normal pelvis (P gt; 0.05), and the differences between other tow groups were significant (P lt; 0.05). Conclusion The LS fixation can provide better stabil ity for posterior pelvic ring fracture dislocation when compared with IG and RP.

    Release date:2016-09-01 09:08 Export PDF Favorites Scan
  • CERVICAL LATERAL MASS PLATE WITH ITS CLINICAL APPLICATION

    Objective To evaluate the fixation technique of using the cervical lateral mass plate in the cervical posterior approach operation. Methods Eight patients in this group were admitted from September 2001 to November 2006. Among the 8 patients, there were 6 males and 2 females, with their ages ranging from 28 to 78 years. Cervical vertebral fracture with dislocation was found in 4 patients, C2 spinal cord injury in 1, C1 fracture in 1, cervical spinal stenosis in 1, and C2-5 spinal cord neurofibroma in 1. Muscle strength 3-4. TheFrankel grading system was usedin 6 patients with traumatic injury. Before operation, Grade C was observed in 2patients,Grade D in 3,and Grade E in 1. All the operations were performed according to requirements of the Margel’s method. We positioned 40 screws in all the patients, including 4 screws at C2,6 screws at C3,12 screws at C4,4 screws at C5,4 screws at C6,2 screws at C7,and 6 screws at T1. Results The followingup for an average of 14.1 months (range,645 months) revealed that there was no malposition of the screws in the patients. One of the 8 patients developed spinal instability in the fixed segment at 3 months after operation. The headchestbrace was applied to the patient for 3 months, and the spinal fusion was achieved. The further followingup to 45 months indicated that there was no instability occurring. The remaining patients recovered to their spinal stability by the spinal fusion. The patients also recovered in their neurological function after operation. The Frankel assessment showed that 1 patient had Grade E, 3 from Grade D to Grade E, 1 from Grade C to Grade D, and 1 from Grade C to Grade E. Conclusion The cervical lateral mass plate fixation can provide the immediate and b segmental immobilization for the good cervical spine stability.

    Release date:2016-09-01 09:20 Export PDF Favorites Scan
  • Research progress on intra-articular screw penetration in proximal humeral fracture treated with locking plate

    ObjectiveTo review the research progress on intra-articular screw penetration in proximal humeral fracture treated with locking plate. MethodsThe domestic and foreign literature about the proximal humeral fracture treated with locking plate was extensively reviewed. The incidence of screw penetration and risk factors were summarized from both primary and secondary screw penetrations, and the reasons of the intra-articular screw penetration and the technical solutions to avoid the penetration were analyzed. ResultsThe incidence of intra-articular screw penetration is about 11%-30%, which includes primary and secondary screw penetrations. The primary screw penetration is related to improper operation, inaccurate measurement, and “Steinmetz solid” effect, which results in inadequate fluoroscopy and blind zone. The secondary screw penetration is related to the loss of reduction and varus, collapse, and necrosis of the humeral head. The risk factors for intra-articular screw penetration include the bone mass density, the fracture type, the quality of fracture reduction, the applied location, number, and length of the plate and screws, and whether medial column buttress is restored. Improved fracture reduction, understanding the geometric distribution of screws, good intraoperative fluoroscopy, and reconstruction of medial column buttress stability are the key points for success. ConclusionThe risk of the intra-articular screw penetration in the proximal humeral fractures treated with locking plates is still high. Follow-up studies need to further clarify the cause and mechanism of screw penetration, and the risk factors that lead to screw penetration, in order to effectively prevent the occurrence of this complication.

    Release date:2021-04-27 09:12 Export PDF Favorites Scan
  • MANUFACTURE AND CLINICAL APPLICATION OF MEDICAL METAL DEBRIS ADSORPTION APPARATUS

    ObjectiveTo introduce a medical metal debris adsorption apparatus and to discuss the application value in removal of locking plate internal fixation. MethodsBetween January 2011 and May 2013, 83 cases underwent removal of locking plate fixation. There were 44 males and 39 females, aged 21-59 years (mean, 35.4 years). The time from the first operation to internal fixation removal was 16-40 months (mean, 22.6 months). Thirty-two screws of 9 patients were removed difficultly due to slide fastener. The screws were removed eventually after plates and screws were separated by grinding locking screw with manganese steel drill. In the process of grinding, the medical metal debris adsorption apparatus was used in 16 screws of 4 patients (group A), and was not used in 16 screws of 5 patients (group B). The operation time, removal time of single slipping screw, intraoperative blood loss, and the score of metal debris residues were compared between 2 groups. And the postoperative complications were recorded. ResultsA total of 658 screws were removed, and 32 slipping screws were found, accounting for 4.86%. The lock screw slipping rates of 3.5 mm and 4.5 or 5.0 mm respectively were 6.53% and 2.31%; and the lock screw slip ping rates of internal fixation time < 2 years and > 2 years respectively were 3.21% and 6.08%. The operation time, removal time of single slipping screw, intraoperative blood loss, and the score of metal debris residues of group A were significantly lower than those of group B (P < 0.05). Re-fracture (1 case) and incision infection (1 case) occurred in group B, and no complication was observed in group A. The cases of 2 groups were followed up 8-35 months (mean, 23.4 months). No heterotopic ossification occurred in both groups during the follow-up. ConclusionThe medical metal debris adsorption apparatus can significantly shorten the operation time, reduce the residual metal debris and surgical bleeding when removing the slipping screws in removal of locking plate internal fixation.

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  • PERCUTANEOUS FIXATION OF PELVIC FRACTURE BY Acutrak FULL THREAD HEADLESS HOLLOW COMPRESSION SCREW

    【Abstract】 Objective To evaluate the effectiveness of percutaneous fixation of pelvic fracture by Acutrak full thread headless hollow compression screw. Methods Between March 2008 and April 2010, 31 patients with pelvic fracture underwent percutaneous fixation surgery with Acutrak full thread headless hollow compression screw (surgical group). The effectivenss was compared with those of 14 patients with pelvic fracture treated conservatively (control group). There was no significant difference in age and sex between 2 groups (P gt; 0.05). The injury was more severe in surgical group than in control group. The standard of short-term recovery was active turning over and walking for 5 steps with walking aids. The standard of long-term recovery was pain, gait, fracture healing, and function recovery. Results In surgical group, the other patients reached the standard of short-term recovery at 1-4 days after injury except 1 patient who had sacral plexus injury; in control group, the patients could turn over at 9-13 days (Tile type A2) and 17-25 days (Tile type B2) respectively, and could walk at 17-21 days (Tile type A2) and at 45-57 days (Tile type B2) respectively. The patients of 2 groups were followed up 6-19 months. The time of fracture healing was 2-6 months. The long-term results were excellent in 29 cases and good in 2 cases in surgical group, and were excellent in 8 cases and good in 6 cases in control group, showing significant difference between 2 groups (χ2=6.636, P=0.017).Conclusion Percutaneous internal fixation combined with Acutrak full thread headless hollow compression screw can provide more effective treatment. It can alleviate patients, pain quickly, improve life quality, and has better long-term effectiveness.

    Release date:2016-08-31 04:21 Export PDF Favorites Scan
  • AN ANATOMIC STUDY OF LAG SCREW PLACEMENT IN ANTERIOR COLUMN OF ACETABULUM AND DESIGN OF TARGETING DEVICE

    Objective To provide the anatomic basis for thelag screw placement in the anterior column of the acetabulum. Methods Twenty-two pelvis specimens with 44 acetabula of the native adult cadavers were studied. The anthropometric measurement was performed on 44 acetabula to determine the shape of the transverse section of the anterior column of the acetabulum, the optimal entry point for the lag screw on the outer table of the ilium, the direction of the screw, and the distance from the entry point to the obturator groove. Results The transverse section of the anterior column of the acetabulum was almost triangle-shaped. The path for the lag screw placement was 10.5±0.8 mm in diameter. The optimal entry point on the posterolateral ilium for the screw fixation was found toexist 9.2±2.4 mm superior to the line between the anterior superior iliac spine and the greater sciatic notch and 38.5±3.8 mm superior to the greater sciatic notch. The distance from the entry point to the obturator groove was 84.1±6.2 mm. The inclination of the lag screw was 54.2±5.5° at the caudal direction in the sagittal plane and 40.7±3.8° in the horizontal plane. The device for the safe screw placement in the anterior column was designed. Conclusion The above datacan facilitate an insertion of one 6.5 mm lag screw into the anterior acetabular column and minimize the risk of articular violation or cortical penetration, which has a narrow margin of safety. The safe length of the lag screw should be 70 mm.The optimal entry point on the posterolateral ilium for the screw fixationis determined to be 10 mm superior to the line between the anterior superior iliac spine and the greater sciatic notch and 40 mm superior to the greater sciatic notch. The inclination of the lag screw should be 55° at the caudal direction in the sagittal plane and 40° in the horizontal plane. It is safe to place thelag screw in the anterior column with the help of the targeting device.

    Release date:2016-09-01 09:26 Export PDF Favorites Scan
  • DESIGN AND CLINICAL APPLICATION OF LESSER TROCHANTERIC REDUCTION FIXATION SYSTEM

    ObjectiveTo design and produce a lesser trochanteric reduction fixation system and verify its value and effectiveness. MethodsA lesser trochanteric reduction fixation system was designed and produced according to the anatomical features of the lesser trochanteric fractures. Sixty-six patients with intertrochanteric fractures of Evans type Ⅲ were included between January 2010 and July 2012. Of 66 patients, 32 were treated with dynamic hip screw (DHS) assisted with the lesser trochanteric reduction fixation system (study group), and 34 cases were treated with DHS only (control group). The 2 groups were comparable with no significant difference in gender, age, the reasons, and the types of the fractures (P>0.05). The operation time, intraoperative blood loss, neck-shaft angle, bone healing time, ratio of successful fixations, and the functional evaluation of the hip joint after operation were compared between 2 groups. ResultsThe study group had shorter operation time [(58.4±5.3) minutes] and less intraoperative blood loss [(186.3±6.6) mL] than the control group[(78.5±6.2)minutes and (246.2±8.7) mL], showing significant differences (t=-14.040, P=0.000; t=-31.145, P=0.000). There was no significant difference in neck-shaft angle between study group [(138.6±3.0)°] and control group [(139.4±2.9)°] (t=-1.044, P=0.301). The wounds healed by first intention in both groups. The 30 and 31 patients were followed up 12 to 24 months (mean, 15 months) in the study group, and 13 to 25 months (mean, 16 months) in the control group, respectively. All fractures healed well in 2 groups. The study group had significantly shorter healing time [(8.8±2.0) weeks] than the control group [(10.7±3.4) weeks] (t=-2.871, P=0.006). At 12 months after operation, coxa vara happened in 2 cases of the study group with a successful fixation ratio of 93.3% and in 10 cases of the control group with a successful fixation ratio of 67.7%, showing significant difference (χ2=6.319, P=0.022). According to Harris hip score, the excellent and good rate was 83.3% in the study group (25/30) and was 58.1% in the control group (18/31), showing significant difference (χ2=4.680, P=0.049). ConclusionThe application of the lesser trochanteric reduction fixation system can reduce stripping of the soft tissue around the fracture fragments, shorten the operation time and the healing time, and preserve the function of the hip joint maximumly.

    Release date:2016-08-25 10:18 Export PDF Favorites Scan
  • A comparative study of absorbable screw fixation and absorbable screw combined with suture anchor fixation in treatment of avulsion fracture of posterior cruciate ligament at tibial insertion of knee joint

    ObjectiveTo compare the effectiveness of open reduction of posterior cruciate ligament (PCL) avulsion fracture at tibial insertion of knee joint with absorbable screws fixation and absorbable screw combined with suture anchor fixation. Methods The clinical data of 26 patients with PCL avulsion fracture at tibial insertion who met the selection criteria between March 2015 and October 2021 were retrospectively analyzed. Among them, 14 patients were fixed with simple absorbable screw (group A), and 12 patients were fixed with absorbable screw combined with suture anchors (group B). All patients were confirmed by X-ray film, CT, or MRI preoperatively, and got positive results in preoperative posterior drawer tests. There was no significant difference in gender, age, side of affected limb, time from injury to operation, comorbidities, and preoperative Meyers & McKeever classification, Lysholm score, and International Knee Documentation Committee (IKDC) score between the two groups (P>0.05). The operation time and postoperative complications were recorded and compared between the two groups. At last follow-up, Lysholm score and IKDC score were used to evaluate the improvement of knee function. ResultsThere was no significant difference in operation time between the two groups (P>0.05). All incisions healed by first intention, and no complication such as vascular and nerve injury or venous thrombosis occurred. All 26 patients were followed up 9-89 months, with an average of 55.3 months. The follow-up time of group A and group B was (55.7±23.2) and (56.8±29.3) months, respectively, with no significant difference (t=−0.106, P=0.916). Radiographs showed bone healing in both groups at 3 months after operation, and no complication such as infection and traumatic arthritis occurred. At last follow-up, the posterior drawer test was negative in both groups, and the Lysholm score and IKDC score significantly improved when compared with the pre-operative values (P<0.05). However, there was no significant difference in the improvement value between the two groups (P>0.05). ConclusionFor PCL avulsion fracture at tibial insertion of the knee joint, the open reduction and absorbable screw combined with suture anchor fixation can achieve reliable fracture reduction and fixation, which is conducive to the early rehabilitation and functional exercise, and the postoperative functional recovery of the knee joint is satisfactory.

    Release date:2023-05-11 04:44 Export PDF Favorites Scan
  • Clinical application of vertebral arch-transverse pathway in pedicle screw implantation

    ObjectiveTo investigate the safety and effectiveness of pedicle screw implantation via vertebral arch-transverse pathway in clinical application by a prospective randomized controlled trial.MethodsTwenty-four patients who were admitted between May 2015 and June 2017 and met the selection criteria for thoracic pedicle screw fixation were included in the study. According to the random number table method, they were divided into the trial group (screw implantation via vertebral arch-transverse pathway) and the control group (traditional screw implantation technology), with 12 patients in each group. There was no significant difference between the two groups in age, gender, cause of injury, injured segment, and the interval between injury and operation (P>0.05). The time of screw implantation was recorded and compared between the two groups. The acceptable rate of screw implantation and the penetration rate of pedicle wall were calculated after operation.ResultsThe time of screw implantation of trial group was (5.08±1.74) minutes, which was significantly shorter than that of control group [(5.92±1.66) minutes], and the difference was significant (t=4.258, P=0.023). Patients in both groups were followed up 1-2 years, with an average of 1.5 years. During the follow-up, no failure of internal fixation occurred. At 1 week after operation, the screw implantation in trial group was rated as gradeⅠin 54 screws, gradeⅡ in 3 screws, and grade Ⅲ in 2 screws, with the acceptable rate of 93.61%. The screw implantation in control group was rated as gradeⅠin 40 screws, grade Ⅱin 10 screws, grade Ⅲ in 8 screws, and grade Ⅳ in 1 screw, with the acceptable rate of 84.75%. There was significant difference in the acceptable rate of screw implantation between the two groups (χ2=3.875, P=0.037). The penetration rate of pedicle wall in trial group was 8.47% (5/59), which was significantly lower than that in the control group [32.20% (19/59); χ2=4.125, P=0.021].ConclusionCompared with the traditional technique, the pedicle screw implantation via vertebral arch-transverse pathway can obtain a good position of the screw canal with higher accuracy and simpler operation.

    Release date:2019-12-23 09:44 Export PDF Favorites Scan
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