Sacral fractures are usually caused by high-energy violence,often complicated with injury to the lumbosacral plexus.In severe cases,they may cause instability of the posterior pelvic ring or of the lumbosacral junction.Their classifications commonly used in clinic are Denis,Tile,Isler and refined Denis type Ⅲ ones proposed by Roy-Camille and Gibbons.Recently,classifications of the lumbosacral lesions and scoring systems of the injury severity have often been used clinically.At present,internal instrumentation of sacral fractures is developing along the direction of high efficiency,safety and minimal invasion,but different methods of internal fixation have their own indications which should be strictly followed.This review summarizes the classifications of sacral fractures and their treatment advances.

Objective To investigate the incidence of heterotopic ossification in cervical artificial disc replacement in Chinese mainland population by meta-analysis.Methods The related literatures published between 1997 and June 2012 were collected from both English databases,including Pubmed,Ovid,Cochrane library and Embase,and Chinese databases including Chinese Biomedical Literature Database,China National Knowledge Infrastructure,VIP database and Wanfang database.Literatures were selected in strict accordance with the inclusion and exclusion criteria.Studies providing data of prevalence of heterotopic ossification after cervical artificial disc replacement in Chinese mainland population were included.The information of literatures was extracted by excerpts questionnaire,and recorded by two independent researchers.I2 was calculated to test heterogeneity among studies.A random effects model was used if I2 ≥25％.Subgroup analysis was done according to the number of levels of disc replacement,brands of implants and duration of follow-up.Sensitivity analysis was done according to the sample size.The Meta-Analyst software was used for statistical analysis.Results A total of forty studies (1822 cases) were included in this study.The pooled incidence of heterotopic ossification was 7.3％ (95％CI:4.7％ to 11.0％).For single and mixed level disc replacement,the incidence was 11.6％ and 5.8％,respectively.For single and mixed level disc replacement using Bryan disc,the incidence was 13.8％ and 5.4％,respectively,and the total incidence was 7.2％.No matter the single or mixed level disc replacement,the incidence of heterotopic ossification increased with follow-up.Conclusion The incidence of heterotopic ossification in cervical artificial disc replacement is high in Chinese mainland population,while it is lower than in foreigners.However,it is necessary to monitor its long-term incidence due to its increase with follow-up.

Objective To investigate the clinical results of the primary total hip replacement (THR) and the secondary THR after failed internal fixation in the elderly patients with displaced femoral neck fracture so as to find the optimal treatment for displaced femoral neck fractures in the elderly patients. Methods From April 2001 to April 2007,16 patients (Study Group) treated with a secondary THR after failed internal fixation and 20 patients (Control Group) treated with a primary THR were enrolled in the study and followed up. There were seven males and nine females, at average age of 66. 5 years (50-85 years) and with mean follow-up period of 58. 25 months (24-96 months) in the Study Group. There were six males and 14 females, at average age of 68.1 years (51-83 years) and with mean follow-up period of 49.50 months (24-70 months) in the Control Group. All patients were active and lucid before they suffered fractures. Blood loss and operation duration in THR were compared. Hip function (Harris score) and health-related quality of life (HRQoL, KPS index score) were assessed during the follow-up after THR. Results Operative duration was (115.63 ±34.35) minutes in Study Group and (91.25 ±15.80) minutes in Control Group (P<0.05). Blood loss was (546.86 ±377.04) ml in Study Group and (320.00 ±155.94) ml in Control Group (P<0.05). At follow up, Harris score and KPS index score were (87. 25 ±7. 53) points and (95. 00 ±5. 16) points respectively in Study Group, and (90.20±5.46) points and (96.00 ±0.73) points respectively in Control Group (P>0.05). There were no infections or re-operations in two groups, but with one death in each group during the follow-up. Conclusions THR is the optimal treatment for displaced femoral neck fractures in the elderly patients.The secondary THR after failed internal fixation has higher risks in operation compared with the primary THR for a displaced femoral neck fracture in the elderly patient.

Objective To investigate the correlation factors for surgical outcome of sacral decompression and lumbopelvic fixation in H-shaped sacral fracture and the methods to prevent and treat the complications.Methods From January 2008 to January 2016,45 patients with H-shaped sacral fracture treated by sacral decompression and lumbopelvic fixation were respectively analyzed,including 29 men and 16 women,mean age 41.2 (range,24-53 years),mean follow-up time 52.6 months (range,16-93 months).The surgical outcome was evaluated by pelvic outcome score,and correlation factors were analyzed.We analyzed whether each factor was in correlation with pelvic outcome score.Then we integrated the statistically significant indicators into Logistic regression equation to determine the related factors.Postoperative complications were all recorded.Results The average operation time was 161.2 min (range,100-220 min),average blood loss was 491.6 ml (range,370-1 000 ml),injury-surgery interval was 7.2 d (range,1-23 d).In terms of pelvic outcome score,31 (68.9％) patients had satisfactory result and 14 (31.3％) patients had unsatisfactory result.Univariate x2 analysis suggested that cauda equina injury,Roy-Camille classification,L5S1 facet injury,fracture line,kyphotic angle,injury-surgery interval,decompression approach and inserting sacral screws were correlated with pelvic outcome score,but gender,age,injury mechanism and L5 pedicle fracture had no relation with pelvic outcome score.The multivariate Logistic regression analysis showed that cauda equina injury,Roy-Camille classification,fracture line,kyphotic angle,injury-surgery interval,decompression approach and inserting sacral screws were closely related to pelvic outcome score,but L5S1 facet injury was excluded.2 patients required early surgical procedures with proper antibiotics for deep wound infection;3 patients complained pain related to hardware prominence and the pain subsided after removal of implants;1 patient got unilateral rod breakage at 3-6 months and achieved bony fusion after nine months of observation.Conclusion Sacral decompression and lumbopelvic fixation is effective in neurological recovery and early ambulation in treating H-shaped sacral fracture.Better surgical outcome is related to timely surgery,preoperative or intraoperative bone traction,sacral screws insertion,incomplete cauda equina injury,Roy-Camille type Ⅱ,fracture line penetrating S2 and kyphotic angle less than 40°.

Objective To evaluate the clinical outcomes of sacral decompression and lumbopelvic fixation for neurologically impaired patients with sacral fracture-dislocation.Methods From January 2009 to December 2013,32 patients with sacral fracture and spino-pelvic dissociation of Roy-Camille types Ⅱand Ⅲ were treated at our department.They were 21 men and 11 women,with a mean age of 34.3 years.According to Roy-Camille classification,9 patients belonged to type Ⅱand 23 to type Ⅲ;25 patients had S1 fracture-dislocation and 7 S2 fracture-dislocation.After their overall conditions were stabilized,all were treated with open reduction,sacral decompression and lumbopelvic fixation.Pre-and post-operative neurological functions were recorded by Gibbons criteria.We analyzed the correlations between the neurological recovery and (i) the extent of cauda equina deficit and (ii) the continuity of sacral roots,as well as the correlations between the functional recovery of the bladder and bowels and the above two.The reduction and fusion status were evaluated by the Mears and Velyvis radiological criteria;clinical effectiveness was evaluated by Majeed scoring system.Intra-and post-operative complications were all recorded.Results The mean follow-up time for this series was 35 months (from 25 to 47 months).The average Gibbons score improved from 4.0 to 2.7 at the follow-ups.The patients with mild cauda equina deficit or with continuity of sacral roots achieved significantly better neurological recovery than those with severe cauda equina deficit or with discontinuity of sacral roots (P ＜ 0.001).However,the functional recovery of the bladder or bowels was not significantly correlated with the extent of cauda equina deficit or with the continuity of sacral roots.Anatomical reduction was achieved in 26 patients,satisfactory reduction in 5 and unsatisfactory reduction in one,yielding a satisfaction rate of 96.9％.Bony fusion was obtained in 29 patients at 3 months,but not until at 9 months in 2 patients,and still not at 9 months in one who showed no symptoms.The Majeed scoring showed 22 excellent,6 good and 4 moderate cases,giving an excellent to good rate of 87.5％.Two patients developed deep wound infection,3 complained of the pain related to hardware prominence,and one had unilateral rod breakage.Conclusions In treatment of sacral fracture with spino-pelvic dissociation,sacral decompression and lumbopelvic fixation can lead to effective neurological recovery,restoration of lumboscacral stability and alignment,early ambulation and prevention of deformity.Complete neurological recovery is more likely in patients with incomplete cauda equina deficit or with continuity of all sacral roots.

Objective To evaluate the feasibility of using gelatin sponge to reduce bone cement leakage in percutaneous vertebroplasty (PVP).Methods A retrospective case control study was conducted to analyze the 191 patients (191 vertebrae) with lumbar osteoporosis vertebrae compression fractures (OVCF) who were treated by PVP from October 2014 to October 2017 in Xi'an Honghui Hospital.There were 52 males and 139 females,aged 65-91 years,with an average of 75.1 years.A total of 48 patients were treated with routine PVP,and bone cement was injected directly after puncture (Group A).A total of 47 patients,49 patients and 47 patients were injected with 1/4,1/3 and 1/2 gelatin sponge before bone cement injection respectively (Group B,Group C and Group D).Postoperative routine X-ray and CT scans were used to compare the amount of bone cement injection,the leakage of bone cement,the visual analogue score (VAS),neurological symptoms and complications before and after operation.Results All patients were followed up for 1-12 months,with an average of 3.6 months.There were no significant differences in the amount of bone cement injection after operation between groups (P ＞ 0.05).There was a significant difference in the cement leakage rate among the groups after operation [Group A:42％ (20/48);Group B:40％ (19/47);Group C:14％ (7/49);Group D:13％ (6/47)] (P ＜ 0.05).The results of pairwise comparison of bone cement leakage rate were as follows:significant differences were found between Group A and Group C as well as between Group A and Group D (P ＜ 0.008 3),but no significant difference was found between Group A and Group B (P ＞ 0.008 3);significant differences were found between Group B and Group C as well as between Group B and Group D (P ＜ 0.008 3),but no significant difference was found between Group C and Group D (P ＞ 0.05).There were no significant differences in VAS among the groups (P ＞ 0.05);VAS was significantly improved after operation within each group (P ＜ 0.05).After operation,two patients had persistent lower back pain and one patient had intraspinal leakage.Wound healing was found in all patients,with no neurological symptoms.Conclusion For OVCF,use of 1/3 or 1/2 gelatin sponge in PVP can reduce bone cement leakage.

Vertebral body augmentation for spine-related diseases has the advantages of minimally invasive surgery,obvious postoperative pain relief,and quick postoperative recovery compared with open surgery.It can quickly reconstruct spinal stability,relieve pain,and improve patients' quality of life.Intraoperative injection of bone cement into the diseased vertebral body carries the risk of bone cement leakage during the process.Knowing well the complications is helpful to the timely clinical treatment so as to avoid delays,and understanding the risk factors can facilitate targeted measures to prevent leakage during surgery.Therefore,to understand the consequences of bone cement leakage,leakage incidence rate,related risks factors and preventative measures is conducive to clinical treatment and surgery safety.The authors discuss the complications and risk factors related to bone cement leakage after vertebral body augmentation,in order to deepen the understanding of bone cement leakage,provide reference for clinical work,and improve the safety of surgery.

Currently,the internal fixation methods for unstable sacral fractures mainly include posterior tension band screw plate fixation,sacroiliac screw fixation,lumbopelvic fixation and triangular osteosynthesis.The purpose of the above internal fixation is to correct the deformity of the pelvic ring and lumbosacral joint and rebuild its stability,but incorrect selection will increase the risk of loosening or breakage of the internal fixation.However,there are no clear guidelines on how to select appropriate internal fixation according to different fracture types.To this end,the author discussed the selection of internal fixation method,the technique of screw placement,the new auxiliary instrumentation technology as well as internal fixation related infection so as to provide reference for the treatment of unstable sacral fractures.

Objective: To compare the curative effects between our self-designed flexible vertebroplasty device and the conventional straight bone cement injector in the treatment of osteoporotic thoracic compression fractures. Methods: A retrospective case-control study was conducted to analyze the clinical data of 140 patients with osteoporotic thoracic compression fracture who had been admitted to Department of Spine Surgery, Xi’an Honghui Hospital from June 2016 to January 2017. They were 61 males and 79 females, aged from 55 to 88 years (average, 70.3 years). Their fractured vertebrae distributed from T5 to T12. Our self-designed flexible vertebroplasty device was used in 67 of them (group A) while the conventional straight bone cement injector in the other 73 patients (group B). The 2 groups were compared in terms of operative time, amount of bone cement injected, distribution ratio of bone cement on the contralateral side, bone cement leakage, and visual analogue scale (VAS), anterior height ratio of the fractured vertebra and kyphosis cobb angle at 1 d, 1 and 2 years after operation. Results: The 2 groups were comparable due to their insignificant differences in preoperative general data (P>0.05). All the patients were followed up for more than 2 years, with an average of 26.7 months. There were no significant differences between the 2 groups in operation time (28.1±4.2 min versus 26.3±3.2 min) or in bone cement leakage [34.3%(23/67) versus 17.8%(13/73)] (P>0.05). However, group A was significantly higher than group B in amount of bone cement injection (5.6±1.2 mL versus 4.9±1.1 mL) and in distribution ratio of bone cement on the contralateral side (71.5%±11.3% versus 65.7%±12.9%), significantly lower than group B in VAS at 1 and 2 years after operation (2.8±0.7 and 3.0±0.9 versus 3.1±0.8 and 3.4±0.8) and in kyphosis cobb angle at 1 and 2 years after operation (25.2°±5.2° and 26.8°±5.5° versus 27.7°±4.9° and 29.1°±1.6°), and significantly higher than group B in anterior height ratio of the fractured vertebra at 1 and 2 years after operation (39.2%±8.1% and 37.1%±7.2% versus 35.4%±7.8% and 33.2%±8.4%) (all P< 0.05). There were no significant differences between the 2 groups in VAS, anterior height ratio of the fractured vertebra or kyphosis cobb angle at one day after operation (P>0.05). Conclusions Compared with the conventional straight bone cement injector, our self-designed flexible vertebroplasty device can lead to better contralateral distribution of bone cement, more effective maintenance of the height of injured vertebra, and better long-term analgesic effect in the treatment of osteoporotic thoracic compression fractures.

Objective:To compare the clinical efficacy between puncture assisted by a "TINAVI" orthopaedic robot versus freehand puncture in vertebroplaty for osteoporotic vertebral compression fracture(OVCF) of the upper thoracic vertebra.Methods:A retrospective study was conducted of the 19 patients (20 vertebral bodies) with OVCF of the upper thoracic vertebra who had been treated at Department of Spine Surgery, Honghui Hospital from January 2018 to March 2019 by robotic vertebroplasty (robot group) and of another 21 counterpart patients (21 vertebral bodies) who had been treated by conventional vertebroplasty from January 2016 to December 2017 (freehand group). Puncture was conducted by a "TINAVI" orthopaedic robot in the robotic vertebroplasty but freehand in the conventional vertebroplasty. The robot group had 5 males and 14 females, aged from 62 to 88 years; the freehand group had 6 males and 15 females, aged from 64 to 83 years. The 2 groups were compared in terms of operation time, bone cement volume, postoperative complications (cement leakage, infection and embolism), visual analogue scale (VAS), Oswestry disability index (ODI), anterior height (AH) and kyphosis angulation (KA) of the injured vertebra at day 1 and last follow-up after surgery.Results:The 2 groups were comparable because there were no significant differences between them in the preoperative general data ( P>0.05). Vertebroplasty via unilateral puncture approach was completed uneventfully in the 19 patients (20 vertebral bodies) in the robot group and in the 21 patients (21 vertebral bodies) in the freehand group. The 40 patients were followed up for 6 to 12 months (mean, 8.3 month). The operation time [(37.9±8.2) min], bone cement volume [(2.3±0.9) mL] and rate of cement leakage (10.0%, 2/20) in the robot group were all significantly less or lower than those in the freehand group [(46.2±9.4) min, (4.2±1.3) mL and 42.9% (9/21)] ( P<0.05). No infection or embolism was observed in either group. There were no significant differences between the 2 groups in VAS, ODI, AH or KA of the injured vertebra at day 1 or last follow-up after surgery ( P>0.05). Conclusion:In vertebroplaty for OVCF of the upper thoracic vertebra, compared with conventional freehand puncture, puncture assisted by a "TINAVI" orthopaedic robot can lead to satisfactory clinical efficacy because it reduces operation time, volume of bone cement injection, and thus incidence of bone cement leakage.