Posterior mono-segment instrumentation for correction of type B thoracolumbar fracture / 中华创伤杂志

Objective To evaluate the clinical outcome of mono-segment transpedicular fixation of type B thoracolumbar fracture.Methods A retrospective analysis was conducted on 40 cases suffering from type B thoracolumbar fracture treated with mono-segment transpedicular fixation from May 2003 to October 2012.According to the AO classification,13 cases were identified with type B1.1,11 type B1.2,11 type B2.2,2 type B3.1,2 type B3.2,and 1 type B3.3.Radiological results were evaluated by measuring compression rate of the fractured vertebra and Cobb' s angle of the vertebra adjacent to the fractured segment.Clinical results were assessed using Frankel classification for spinal cord injury and visual analogue scale (VAS) for pain.Results Mean operation time was 71 minutes and mean intrao perative blood loss was 105 ml.Mean period of follow-up was 47.5 months (range,24-82 months).Mean Cobb' s angle of the vertebra adjacent to the fractured segment and compression rate of the fractured vertebra revealed great correction at one week post-operation compared with preoperative ones (6.2° vs 20.1° and 10.1％ vs 38.9％ respectively,P ＜0.05) and there was no significant correction loss at the last follow-up (6.9° and 10.8％ respectively,P ＞ 0.05).Mean VAS was 8.6 points before operation,but mean VAS was 2.4 points at final follow-up (P ＜ 0.05).Neurological performance improved in 37 cases (93％).No cases experienced neurological deterioration.Conclusions Mono-segment transpedicular fixation has small incision,short operation time,few bleeding and decreased motor function loss.The procedure is indicated for most type B thoracolumbar fracture and clinical results are satisfactory.

Outcomes of two types of short-segment pedicle screw fixation for thoracolumbar fractures / 中华骨科杂志

Objective To investigate the feasibility of mono-segment pedicle instrumentation (MSPI)in management of thoracolumbar fracture (AO classification,A1 and A3) by being compared with short-segment(two-segment) pedicle instrumentation(SSPI).Methods Overall 141 patients with tape A1 or A3 thoracolumbar fractures,aged from 20 to 60 years (average,40.5 years),were enrolled in this prospective study.According to a simple randomized method,35 patients with type A1 fracture and 41 patients with type A3fracture were treated with MSPI,while 26 with type A1 fracture and 39 with type A3 fracture were treated with SSPI.Low back outcome score (LBOS) and ASIA2000 were used to evaluate clinical outcome.Eighteenth month postoperatively was assigned as the last follow up period.Wedge index (WI) and sagittal index (SI) of the affected vertebrae on radiography were measured and compared preoperatively,one week postoperatively and at the final follow-up.Results All patients were followed up successfully.The blood loss and duration of operation of MSPI group were significantly less than that of SSPI group,respectively.However,there were no significant differences of clinical outcome between two groups.For type A1 fracture,correction rate and correction loss of WI in MSPI group were better than those in SSPI group.For type A3 fracture,there were no significant differences of correction rate and correction loss of WI and SI between MSPI group and SSPI group; however,the failure rate of MSPI group was significantly higher than that of SSPI group.Conclusion For type A1 and partial type A3 thoracolumbar fractures,MSPI can provide the same or better fixation with less blood loss and operative duration than SSPI.Since MSPI for type A3.2 thoracolumbar fracture has a higher failure rate,the surgical indication should be strictly controlled.

Ball tip probe technique for pedicle screw placement / 中华骨科杂志

ObjectiveThe aim in this study was to evaluate the efficacy of the ball tip probe technique in placing pedicle screws in patients.MethodsFrom May 2009 to June 2010,we used ball tip probe technique in pedicle screw placement in patients with scoliosis,spondylolisthesis,spinal fractures and other diseases.The ball tip probe consisted of a metal shaft with a metal ball-shaped tip whose size included 1.5,2.5,3.0,3.5 mm in diameter.The ball tip probe with a diameter of 1.5mm owned a high rigidity and certain flexibility.Ball tip probe technique:A high speed bur was used to remove cortical bone and create a starting point,and then the ball tip probes is tapped gently by a hammer for making a guide hole through the pedicle into the vertebral body.The accuracy of the pedicle screw placements was evaluated on postoperative axial CT scanning The pedicle screw placements was compared between the the ball tip probe group and conventional freehand technique group.ResultsThree hundred and twelve screws were evaluated in the ball tip group and 276 in the conventional freehand group.All the screws (100％) were in the desired pedicle in the ball tip group and 215 (78％) in the conventional group.In the conventional group,23 screws(8.3％) were classified as medial violation; 38(13.7％) as lateral violation.A significant difference was determined between the 2 groups regarding the pedicle breaches.No vascular,pulmonary,or neurological injuries caused by pedicle screws placement was found in either group.ConclusionThis study demonstrates the accuracy and reliability of the ball tip probe technique in pedicle screw placement.This technique can probably reduce the risk of complications of screw misplacements.

The therapeutic effect of different posterior circumferential fusion on lumbar instability in aged patients / 中华老年医学杂志

ObjectiveTo compare the clinical effect of posterior circumferential fusion with versus without intertransverse process fusion on lumbar instability in aged patients. MethodsThe elderly with lumbar instability were treated with the posterior instrumented circumferential fusion technique in 80 cases. Among 58 patients followed up for at least 2 years, 28 cases (group A)underwent posterior circumferential fusion with intertransverse process, while 30 cases (group B)without intertransverse process. X-ray examination was used before and 1, 3, 6, 12 and 24 months after operation to evaluate the fusion condition of the bone graft, and visul analogue scale (VAS) and Oswestry disability index (ODI) questionnaire were applied to assess the pain of center back and leg,and the conventional activity.ResultsThe operation time and blood loss were more in group A[(185.3±56.6) min and (376.3±92.9) m1] than in group B [(146.4±46.3) min and (234.3±64.5)ml (t=12.37, 37.49, P＜0.01)]. All the 58 cases were followed for at least 2 years. The 27 cases (96.4％) of group A and 28 cases (93.3％) of group B got bone fusion (x2 =0.004, P＞0.05).There were marked differences in the VAS of center back at 1 and 3 months after operation between the 2 groups (t=3.178, 2.158, both P＜0.05), while no difference at the other 3 time point. VAS about the leg pain and the ODI showed no differences between group A and B after operation (all P＞0.05). ConclusionsFor the lumbar instability in the elderly, the posterior circumferential fusion with or without intertransverse process fusion can achieve a similar high rate of fusion and satisfactory clinical results,andtheposteriorcircumferentialfusionwithoutintertranaverseprocess is recommended for less trauma.

Posterior circumferential fusion for the mechanical instability of lumbar spine / 中国医师进修杂志

Objective To analyze and evaluate the effect of posterior circumferential fusion for treatment of the mechanical instability of lumbar spine, and discuss the relative merits,indications and contraindications in this procedure. Methods Two hundred and two patients with mechanical instability of lumbar spine treated by the posterior instrumented circumferential fusion technique from January 2001 to January 2007. One hundred and thirty-two patients were selected who were treated with only one segment fusion and followed up for at least 1 year, of them 97 patients suffered lumbar spondylolisthesis, 35 patients suffered degenerative lumbar instability. X-ray was used to evaluate the fusion condition of the bone graft, and VAS and ODI questionnaire were applied to assess the pain of back and leg,and the conventional function. Results All patients were followed up for 12-84 months, averaged (43±23) months,125 patients got bone fusion, accounted for 94.7%(125/132). The VAS of low back pain was (6.71 ± 1.31) points before operation, while (3.20 ± 1.14) points after operation (P < 0.05) ,and the VAS of leg pain was (8.33 ± 1.78) points before operation,while (4.31 ± 1.15) points after operation (P< 0.05). The ODI was (68.6 ± 14.7) % before operation, while (13.6 ± 1.5) % after operation (P < 0.05). Conclusions Posterior circumferential fusion is a positive and excellent treatment for the mechanical instability of lumbar spine. With its merits, the high fusion rate and good clinical results can be received.

Application of Wallis dynamic stabilization system in surgical treatment of lumbar segmental instability: Effect evaluation / 中国组织工程研究

BACKGROUND: Posterior lumbar non-fusion devices have been developed to control vertebral column movement, change load pattern of instability segment, restrict abnormal action, as well as avoid adjacent segment degeneration.OBJECTIVE: To investigate the efficiency of Wallis dynamic stabilization system in the treatment of lumbar vertebrae instability.METHODS: Ten cases suffering from lumbar instability were selected, including 3 males and 7 females, aged 43-65 years. One patient sustained L_(1/2) and L_(4/5) segmental instability, one was L_(2/3) and another was L_(3/4), and the others were L_(4/5). Two patients complicated with lumbar disc herniation and 7 patients combined with lumbar spinal stenosis at the same affected segment, and 3 patients associated with lumbar spinal stenosis at adjacent segment. All unstable segments were treated with decompression, posterior implantation of Wallis dynamic stabilization system. Visual analogue scale (VAS) and Japanese Orthopedic Association (JOA) scores for low back pain and Oswestry disability index (ODI) were used to evaluate clinical outcomes. In addition, therange of motion (ROM) at the instrumented segment and adjacent segments and posterior disc height (PDH) in standing and extension position at L_(4/5) segment were also measured.RESULTS AND CONCLUSION: All the patients were followed-up for 2-13 months, mean 9.2 months. The mean operation duration was 128 minutes (90-185 minutes), with bleeding volume of 264 Ml (50-600 Ml). Sings and symptoms of all patients were improved significantly after operation, except one patient with recurrence of L_(4/5) lumbar spinal stenosis at 3 month after surgery, whose symptoms relieved by revision with fenestration and decompression. The postoperative VAS was dramatically decreased than that of preoperation (P=0.003); the JOA score was obviously increased (P=0.002), and the ODI score was decreased (p=0.008). The postoperative range of motion decreased significantly (P<0.05). However, there was no obviously difference between preoperative and postoperative L_(3/4), L_5/S_1 and posterior disc height (P>0.05). Good clinical results can be achieved by surgical intervention with Wallis dynamic stabilization system in treating lumbar vertebrae instability.

Efficacy of monosegmental pedicle instrumentation in treatment of traumatic thoracolumbar burst fractures / 中华创伤杂志

Objective To evaluate the clinical efficacy of monosegmental pedicle instrumentation in management of thoracolumbar burst fractures. Methods A total of 67 patients with traumatic thora-columbar burst fractures (type A3.1 and A3.2) were treated with monosegmental pedicle instrumentation in our department from October 2003 to February 2008. Imageologic effect was observed by measuring sagittal index and wedge index via X-ray and clinical outcomes evaluated by using low back outcome score. Results All operations were performed successfully, with average operation duration of 93 mi-nutes and average intraoperative blood loss of 157 ml. Of all, 65 patients were followed up for 4-27 months (average 19.8 months), which showed that all the patients achieved bony fusion, with no implant failure except for one with screw loosening. The sagittal index and wedge index were 13.06°and 42.9% preoperatively and 4.47° and 21.78% postoperatively, with statistical difference (P <0.01). The final follow-up showed no significant correction loss except for two patients (P < 0.05). The low back outcome scores of all patients at follow-up were improved significantly (P < 0.05). Conclusions Monoseg-mental pedicle instrumentation has advantages of minimal invasion, short operative duration, less blood loss and less vertebral motion segment loss and hence is an effective and reliable operative technique for thoracolumbar burst fractures.

Biomechanical evaluation of internal fixation of different anterior canulated screws for the treatment of type odontoid fracture / 中国组织工程研究

BACKGROUND:Antedor canulated screw has been considered an ideal method to treat odontoid fracture.OBJECTIVE:To compare the biomechanical properties of different anterior screws.DESIGN,TIME AND SETTING:A randomized contrast study was performed at the Biomechanics Laboratory of Southern Medical University from March to September 2006.MATERIALS:Double-thread canulated screws and single-thread canulated screws were made of titanium alloy and provided by Shuangyang Medical Apparatus Co.,Ltd.,Suzhou.METHODS:A total of head-neck complexes (C0-C3) which were collected from 20 corpses were maintained in formaldehyde for less than 3 months;thereafter,the muscles and ligaments were removed to obtain the axis specimens so as to make type Ⅱ odontoid fracture models.The fracture samples were individually treated with double-thread and single-thread canulated screws,with 10 samples for each group.MAIN OUTCOME MEASURES:The shear stiffness and the maximum resistance of the two kinds of screw were tested in this study.RESULTS:The shear stiffness of the double-thread screw group was significantly higher than the single-thread screw group (P＜0.01 );however,there was no significant different in the maximum resistance between the two groups (P＞0.05).CONCLUSION:Double-thread canulated screws have a strong biomechanical stability for treating odontoid fracture;therefore,the first choice of the internal fixation should be double-thread canuiated screws for patients with osteoporosis or those who are susceptible to expanded screw pathway during surgical procedures.

Application of hydroxyapatite artificial bone in bilateral open-door posterior cervical expansive laminoplasty / 中国组织工程研究

BACKGROUND:Hydroxyapatite (HA) artificial bone,as bone grafting substitute,would not cause inflammatory reaction or immunological rejection and possesses good biocompatibility after transplantation into human body.It is a novel implant material with bone conduction ability.OBJECTIVE:To investigate the efficacy of HA artificial bone in bilateral open-door posterior cervical expansive laminoplasty and to make a comparison with autogenous bone.DESIGN,TIME AND SETFING:A retrospective case analysis was performed at the Department of Spine Surgery,Hungpuyuan Branch,the First Affiliated Hospital of Sun Yat-sen University from March 2001 to December 2008.PARTICIPANTS:Seventy patients with cervical spondylosis complicated by compression in 3 or more segments or by cervical stenosis and additional fifteen patients with cervical stenosis complicated by cervical trauma were included in this study.METHODS:A bilateral open-door posterior cervical expansive laminoplasty was performed,in which,23 patients received autogenous bone transplantation (autogenous bone group) and 62 patients underwent HA artificial bone transplantation (HA group).MAIN OUTCOME MEASURES:① Japanese Orthopaedic Association (JOA) score pdor to and after surgery,surgery time,and intraoperative bleeding.② HA artificial bone-host biocompatibility.RESULTS:All eighty-five patients were followed up for more than 3 months.There was no significant difference in JOA scores no matter prior to or after surgery between the autogenous bone and HA groups (P＞0.05).The surgery time averaged 85.2 minutes (range 65-110 minutes) in the HA group and averaged 116.4 minutes (range 75-150 minutes) in the autogenous bone group.The intraoperative bleeding averaged 210 mL (range 130-400 mL) in the HA group and averaged 260 mL (range 170-500 mL) in the autogenous bone group.There were no material-host response and other severe complications found in each group,except HA artificial bone fragmentation in 3 patients from the HA group.CONCLUSION:HA artificial bone yields good efficacy and causes fewer complications in bilateral open-door posterior cervical expansive laminoplasty;in addition,it requires less time for surgery and causes less bleeding.