Application of a novel porous tantalum implant in rabbit anterior lumbar spine fusion model: in vitro and in vivo experiments / 中华医学杂志(英文版)

BACKGROUND@#Some porous materials have been developed to enhance biologic fusion of the implants to bone in spine fusion surgeries. However, there are several inherent limitations. In this study, a novel biomedical porous tantalum was applied to in vitro and in vivo experiments to test its biocompatibility and osteocompatibility.@*METHODS@#Bone marrow-derived mesenchymal stem cells (BMSCs) were cultured on porous tantalum implant. Scanning electron microscope (SEM) and Cell Counting Kit-8 assay were used to evaluate the cell toxicity and biocompatibility. Twenty-four rabbits were performed discectomy only (control group), discectomy with autologous bone implanted (autograft group), and discectomy with porous tantalum implanted (tantalum group) at 3 levels: L3-L4, L4-L5, and L5-L6 in random order. All the 24 rabbits were randomly sacrificed at the different post-operative times (2, 4, 6, and 12 months; n = 6 at each time point). Histologic examination and micro-computed tomography scans were done to evaluate the fusion process. Comparison of fusion index scores between groups was analyzed using one-way analysis of variance. Other comparisons of numerical variables between groups were made by Student t test.@*RESULTS@#All rabbits survived and recovered without any symptoms of nerve injury. Radiographic fusion index scores at 12 months post-operatively between autograft and tantalum groups showed no significant difference (2.89 ± 0.32 vs. 2.83 ± 0.38, F = 244.60, P = 0.709). Cell Counting Kit-8 assay showed no significant difference of absorbance values between the leaching liquor group and control group (1.25 ± 0.06 vs. 1.23 ± 0.04, t = -0.644, P = 0.545), which indicated the BMSC proliferation without toxicity. SEM images showed that these cells had irregular shapes with long spindles adhered to the surface of tantalum implant. No implant degradation, wear debris, or osteolysis was observed. Histologic results showed solid fusion in the porous tantalum and autologous bone implanted intervertebral spaces.@*CONCLUSION@#This novel porous tantalum implant showed a good biocompatibility and osteocompatibility, which could be a valid biomaterial for interbody fusion cages.

Comparison of percutaneous and open pedicle screw system in the treatment of multilevel thoracolumbar fractures: the accuracy of screw placement / 中国组织工程研究

BACKGROUND: Multilevel thoracolumbar fractures are mainly treated with percutaneous pedicle screw and open pedicle screw system, but the treatment effect of different systems and the accuracy rate of screw placement are controversial, resulting in the lack of uniform standards for choosing the treatment method. OBJECTIVE: To evaluate the effect of percutaneous pedicle screw and open pedicle screw system in the treatment of multilevel thoracolumbar fractures and to evaluate the accuracy of the screw placement. METHODS: Totally 90 patients with multilevel thoracolumbar fractures were divided into open pedicle screw group (n=43 cases) and percutaneous pedicle screw group (n=47) according to different surgical methods. Open pedicle screw group was treated with open pedicle screw treatment, and percutaneous pedicle screw group was treated with percutaneous pedicle screw. Comprehensive effects were analyzed by comparing perioperative indicators (operation time, postoperative drainage volume, and incision length) imaging index (anterior vertebral height percentage, posterior vertebral height percentage, sagittal Cobb angle), postoperative complications, and pedicle screw accuracy. RESULTS AND CONCLUSION: (1) The amount of bleeding, postoperative drainage volume, and incision length were less (shorter) in the percutaneous pedicle screw group compared with the open pedicle screw group (P < 0.05). However, operation time and the number of undergoing fluoroscopy were longer (more) in the percutaneous pedicle screw group than in the open pedicle screw group (P < 0.05). (2) Anterior vertebral height percentage and posterior vertebral height percentage were higher in the percutaneous pedicle screw group than in the open pedicle screw group (P < 0.05). Sagittal Cobb angle was smaller in the percutaneous pedicle screw group than in the open pedicle screw group (P < 0.05). (3) At 2 months after surgery, the complication rate was significantly lower in the percutaneous pedicle screw group (4%) than in the open pedicle screw group (14%) (P < 0.05). (4) The accuracy rate of pedicle screw was significantly higher in the percutaneous pedicle screw group (92.1%; 279 screws) than in the open pedicle screw group (77.0%; 257 screws) (P < 0.05). (5) Results indicated that percutaneous pedicle screw fixation is characterized by less trauma and rapid recovery in the treatment of multilevel thoracolumbar fractures. It is helpful for the reduction of the injured vertebra, the maintenance of vertebral height; the safety and the accuracy of screw placement are high.

Clincial effect of 3D printing-assisted minimal invasive surgery through a small incision lateral to the rectus abdominis for pelvic fracture / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the clinical effect of 3D printing-assisted minimal invasive surgery on pelvic fracture by plate internal fixation through a small incision lateral to the rectus abdominis.</p><p><b>METHODS</b>This retrospective study was conducted among 50 patients with pelvic fracture undergoing anteromedial plate internal fixation between September, 2013 and June, 2015. Thin-layer computed tomography scan data of the patients were input into Mimics software in DICOM format for 3D editing and virtual surgery before the operation. The pelvic model was created by 3D printing. Simulated operation was performed to design the optimum location of the plate screw, prelflex of the plate, screw length measurement and screwing approach. Diaplasis and internal fixation were performed through the extraperitoneal space with a small incision lateral to the rectus abdominis. Matta standard was employed for diaplasis evaluation, and Majeed assessment was used for function evaluation 6 months after the operation.</p><p><b>RESULTS</b>According to Matta standard, excellent and good diaplases were achieved in 96% of the cases, as compared with 94% according to Majeed assessment. Radiographic examination showed a good consistency between the internal fixation and simulated operation. No screw entry into the hip joint cavity occurred in these cases. The mean operation time was 127 min in these cases with a mean intraoperative blood loss of 728 mL and a mean incision length of 8.4 cm. Based on the postoperative VAS score, 12 patients reported severe pain, 28 reported moderate pain and 10 reported mild pain. All the patients were advised for early functional exercise after the operation and clinical healing was achieved in a mean of 8 weeks.</p><p><b>CONCLUSIONS</b>3D printing with simulated operation can improve the accuracy and safety of the operation. Preoperative simulation of plate preflex and screw length measurement can shorten the operation time. A small incision lateral to the rectus abdominis allows minimally invasive operation for pelvic fractures.</p>

Preliminary study for classification of spino-pelvic sagittal alignment in adult volunteers / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the feasibility of the classification of the spino-pelvic sagittal alignment in adluts according to lumbar lordosis (LL) and inflection point (IP).</p><p><b>METHODS</b>Whole spine, standing radiographs of 223 adult volunteers were taken from July to August in 2011 .There were 111 cases(56 female and 55 male) enrolled in the study based on the inclusion criteria. The pelvic and spinal parameters, including thoracic kyphosis(TK), thoracolumbar kyphosis(TLK), LL, sacral slope(SS), pelvic tilt(PT), pelvic incidence(PI), intervertebral endplate angle, sagittal vertical axis (SVA), spino-sacral angle (SSA) and IP were measured. The spino-pelvic sagittal alignment were classified in to 3 types according to LL and IP. Type I: LL > -40°, IP located below L2 ∼ 3; Type II: -60° ≤ LL ≤ -40°, IP located in L1 ∼ 2 or T12 ∼ L1; Type III: LL < -60°, P located above T11 ∼ 12. Pearson correlation analysis was used to test the correlation between the variables. The parameters in each type were compared by oneway-ANOVA respectively,then additional multiple comparisons were performed.</p><p><b>RESULTS</b>The mean value of LL was -49° ± 10°, TK was 36° ± 7°, TLK was 6° ± 7°, PT was 11° ± 7°, SS was 34° ± 8°, PI was 45° ± 9°, SSA was 127° ± 9° and SVA was (-2.7 ± 22.8)mm, respectively. Only LL had significant statistical correlation with all the other parameters. Negative correlation presented between LL and TK, PI, SS, SSA (r = -0.387, -0.536, -0.858, -0.801,P < 0.05). Positive correlation presented between LL and TLK, SVA, PT (r = 0.319, 0.296, 0.262, P < 0.05). All the volunteers were classified into the 3 types: Type I1 9 cases, Type II 75 cases,Type III 17 cases. Oneway-ANOVA results showed statistical difference in LL, TK, TLK, PT, SS, PI, SSA, SVA among the 3 types, (F = 164.559, 7.431, 14.099, 4.217, 53.856, 6.252, 35.995, 8.626, P < 0.05 ). Multiple comparisons showed that LL, SS, SSA, PI had statistical difference between each two types comparison (P < 0.05).</p><p><b>CONCLUSIONS</b>LL is the central parameter of the spino-pelvic sagittal balance. The patterns of the spino-pelvic sagittal alignment in adults could be classified into three types, according to LL and IP. The classification could describe the morphological differences and balance of the spino-pelvic sagittal alignment.</p>

Preliminary clinical results of endoscopic assisted anterior lumbar interbody fusion / 中华外科杂志

<p><b>OBJECTIVE</b>To summarize the experiences of endoscopic assisted anterior lumbar interbody fusion (ALIF) with self-locking cage via retroperitoneal approach through small incision lateral to abdominal rectus.</p><p><b>METHODS</b>There were 47 cases of endoscopic assisted ALIF from April 2010 to April 2012 were reviewed retrospectively, including 28 male and 19 female patients whose age ranged from 39 to 65 years, averaged of (48 ± 11) years. Of 47 cases, 17 cases were founded instability in lumbar spine, 16 cases of discogenetic low back pain, 7 cases of degenerative spondylolithesis, and 7 cases of recurrent disc herniation. The level involved included 7 cases at L3-4 level, 33 cases at L4-5 level, 7 cases at L5-S1. X-ray and/or 3D CT scan were done in each patient at post-operative day 4, 1 month, 3 months, and 6 months. The height and angle of disc space, angle of lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS) were recorded and measured, as well as length of incision, operation time, blood loss, complications and ratio of bone graft fusion. The clinical outcomes were evaluated by Oswestry disability index (ODI) and visual analogue scale (VAS).</p><p><b>RESULTS</b>Average length of incision was (6.2 ± 0.8)cm (5.3-7.8 cm) , average blood loss was (81 ± 20)ml (50-150 ml) , mean operation time was (96 ± 10)minutes (65-122 minutes) . There were significant improvement of ODI(48% ± 10% vs. 14% ± 5%), the VAS of back pain(6.3 ± 1.1 vs.0.7 ± 0.7) and VAS of leg pain(3.4 ± 2.1 vs.0.6 ± 0.6) during preoperative and postoperation last follow-up (t = 20.78, 25.92 and 8.74, P = 0.000). The disc height of operative segments were all recovered significantly (F = 18.971, P = 0.000) postoperatively, from preoperative (10.3 ± 2.4)mm to postoperative (12.6 ± 2.1)mm. For complications, 5 cases had peritoneum tear, 19 cases had bone donor site pain, 14 cases had abdominal distension and 5 cases had lower limb paraesthesia, which were all treated with supportive managements. Bony intervertebral fusion was obtained in all cases in 6 months postoperatively.</p><p><b>CONCLUSIONS</b>The advantages of endoscopic assisted ALIF with self-locking cage via retroperitoneal approach are less damage, rapid recovery, and less blood loss. Comparing with traditional ALIF procedure, the view of operative field is also improved.</p>

The use of anterior cervical discectomy and fusion with self-locking cages to treat multi-segmental cervical myelopathy / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the use of anterior cervical discectomy and fusion with self-locking cages to treat multi-segmental cervical myelopathy.</p><p><b>METHODS</b>From April 2008 to March 2010, anterior cervical discectomy and fusion with self-locking cages were performed on 45 patients who suffered from multi-segmental cervical myelopathy, among of them there were 23 male and 22 female, aged from 32 to 67 years (average 53 years). Recording the Japanese Orthopedic Association (JOA) scores and SF-36 scores in the protocol time point, in order to investigate the clinical outcome, meanwhile, accumulating the pre-operation and postoperation X-ray films of cervical spine for measuring the height of intervertebral space, whole curvature of cervical spine and the rate of fusion by repeated measures analysis of variance.</p><p><b>RESULTS</b>The mean follow-up time was 28.4 months (24 - 35 months). JOA scores ascended from preoperative 6.5 ± 3.1 to postoperative 13.4 ± 1.7 (F = 17.84, P = 0.001), the 7 scores of SF-36 improved significantly after operation (t = 1.151 - 12.207, P < 0.05), but mental health not. The fineness rate was 91.1%. Height of disc space ascended from preoperative (5.5 ± 1.8) mm to postoperative (8.3 ± 0.8) mm (F = 11.71, P = 0.043), globle curvature of cervical spine ascended from preoperative 5° ± 7° to postoperative 10° ± 14° (F = 234.53, P = 0.000), the change of the two index was significantly, respectively. Fat necrosis in one case and hematoma in another case at the bone donor-site were found, both of the two cases were cured by physiotherapy. All of the 45 cases (111 segments) achieved bone fusion.</p><p><b>CONCLUSION</b>The use of anterior cervical discectomy and fusion with self-locking cages to treat multi-segmental cervical myelopathy possess many advantages as follows: satisfactory clinical outcome, minimally invasive, higher fusion rate, higher orthopaedic ability.</p>

Establishment of a rabbit model of lumbar intervertebral disc degeneration via the paraspinal approach / 南方医科大学学报

<p><b>OBJECTIVE</b>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.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>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.</p>

Effect of new nucleus pulposus replacement on the flexibility motion and intradiscal pressure at the adjacent level / 医用生物力学

Objective To evaluate the biomechanical stability of pectin/polyvinyl alcohol composite （CoPP）hydrogel and to assess the range of motion(ROM) and intradiscal pressure (IDP) changes at the above adjacent segment after the anterior implantation of CoPP hydrogel and cage. Method Six fresh cadaveric lumbar spine specimens（L3～L5）were biomechanically tested on the robotic testing machine. ROM at L3/4 and L4/5 and intradiscal pressure at L3/4 were measured. All measurements were made with initially intact and followed by both CoPP and cage implantations. Results At the implanted level (L4/5), the CoPP spine showed no significant change in the other five motion directions except left lateral bending motion compared with the intact spine (P>0.05), whereas the cage spine decreased significantly in all motion directions when compared with the intact spine or CoPP spine (P0.05), whereas the ROM of cage spine significantly increased in all motion directions compared with the intact spine (P0.05). While the IDP of cage spine significantly increased in flexion/extension and left/right lateral bending compared with the intact spine or CoPP spine (P0.05). Conclusions The implantation of CoPP prosthetic nucleus can preserve the motion function at the operated level and maintain the lumbar stability. Compared with the lumbar fusion, the nucleus replacement has no significant effect on the ROM and IDP at adjacent level, which may decrease or avoid the adjacent segment degeneration.

The application of cervical arthroplasty with Mobi-C for treatment of cervical spondylotic radiculopathy / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the clinical effectiveness of cervical arthroplasty with Mobi-C prosthesis for treatment of cervical spondylotic radiculopathy.</p><p><b>METHODS</b>From March 2008 to November 2009, a group of 67 patients with cervical spondylotic radiculopathy were analyzed retrospectively. The short form-36 physical component summary (SF-36) and visual analogue scale (VAS) score were used to compare clinical outcome pre- and postoperatively. The follow-up was performed at 3 d, 3 months, 6 months and 1 year postoperatively. Static and dynamic radiography were taken to evaluate height of disc space, range of motion (ROM) and heterotopic ossification (HO) of index levels.</p><p><b>RESULTS</b>Fifty-one cases were followed up, 16 cases were lost. Average follow-up was for 19.7 months (13 - 31 months). All of patients had improvement for clinical symptoms. There was a significant difference on SF-36 between pre- and postoperatively. The significant difference was found in VAS score in which neck pain was decreased from preoperative 4.6 ± 0.4 to postoperative 2.0 ± 0.5 (P < 0.05), arm pain was decreased from preoperative 6.5 ± 0.4 to postoperative 1.3 ± 0.4 (P < 0.05). There was a significant difference in height of disc space which was increased from preoperative (6.5 ± 1.1) mm to (7.7 ± 0.9) mm (P < 0.05). ROM was increased from preoperative 7.2° ± 3.1° to latest follow-up 8.1° ± 3.2°, however, no significant difference was found concerning ROM pre- and postoperatively (P > 0.05). No other complications were met during follow-up period other than the 17 cases of heterotopic ossification in ClassI, the 7 cases in Class II in 1 year postoperatively, but no any correlation were found between the radiographic finding in HO and clinical symptoms.</p><p><b>CONCLUSIONS</b>Cervical arthroplasty with Mobi-C could improve neurofunctional symptoms, maintain ROM of index level and height of disc space. For accurate patient selection, long term follow-up is still needed in prospective randomized study.</p>

In vivo experimental study of lumbar nucleus replacement with pectin/polyvinyl alcohol composite hydrogel / 中华外科杂志

<p><b>OBJECTIVE</b>To evaluate the anti degenerative effect of pectin/polyvinyl alcohol composite (CoPP) hydrogel as artificial nucleus material in an animal model.</p><p><b>METHODS</b>Thirty-six New Zealand white rabbits were used to build animal models, the L₄₋₅ intervertebral discs were pierced with a Gauge#16 needle and polyvinyl alcohol (PVA) or CoPP implants were inserted into the holes. For comparative purposes, L₃₋₄ discs underwent sham treatment or control treatment in which the disc was pierced but no implant was inserted. All the discs were divided into four groups as follows: sham disc group, pierced disc group, PVA disc group and CoPP disc group. The discs were analyzed radiologically and histologically for degenerative changes at 1, 3 or 6 months after surgery.</p><p><b>RESULTS</b>None of the animals died from operative complications, such as paraplegia or infection before being killed. Macroscopically, none of the implants showed any signs of displacement at the time of harvest. The radiological analysis revealed that significantly less disc height loss was found with the PVA and CoPP replacement treatment than with the pierced treatment (P < 0.05). Changes in disc height after the replacement treatment were not significantly different from that after the sham treatment (P > 0.05). Histological degeneration of the replaced discs was delayed in comparison with that of the pierced discs (P < 0.05), but progressed with time, and PVA replacement showed faster disc degeneration than CoPP replacement.</p><p><b>CONCLUSIONS</b>Degeneration of the anulus fibrosus after the CoPP prosthetic nucleus replacement treatment is delayed by preserving disc height and occupying the space of the nucleus pulposus, and it has great potential clinical application value.</p>

Factors affecting adjacent segment degeneration after rigid lumbar internal fixation / 南方医科大学学报

<p><b>OBJECTIVE</b>To analyze the factors affecting the occurrence of adjacent segment degeneration (ASD) after lumbar internal fixation.</p><p><b>METHODS</b>The clinical data of 147 surgical patients with lumbar disc herniation, lumbar spinal stenosis and lumbar spodylolisthesis undergoing surgeries between January 2002 and July 2007 in our hospital were reviewed. The correlations of gender, range of fixation, position of fixation, and characteristic of the adjacent disc to the occurrence of ASD were analyzed.</p><p><b>RESULTS</b>The patients were followed up for a mean of 30-/+10 months (18-84 months). The incidence of ASD was 13.6% in these patients, occurring all at the cephalad adjacent segment. The presence of preoperative degeneration of the adjacent disc gave rise to increased risk of ASD following the surgery (chi(2)=6.272, P=0.012), and multivariate analysis indicated that preoperative adjacent disc degeneration was a risk factor for postoperative ASD (P=0.046), but gender, range of fusion and site of fusion were not the risk factors.</p><p><b>CONCLUSION</b>Presence of adjacent segment degeneration before the operation is associated with a significantly increased risk of postoperative ASD.</p>

Lithium chloride combined with human umbilical cord blood mesenchymal stem cell transplantation for treatment of spinal cord injury in rats / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the effects of lithium chloride combined with human umbilical cord blood mesenchymal stem cell (hUCB-SCs) transplantation in the treatment of spinal cord injury in rats.</p><p><b>METHODS</b>Eighty female SD rats with complete T9 spinal cord transaction were randomized into 4 groups (n=20), namely the control group (group A), lithium chloride group (group B), hUCB-SCs group (group C) and hUCB-SCs(+) lithium chloride group (group D). On days 1 and 3 and the last days of the following weeks postoperatively, the motor function of the hindlimb of the rats were evaluated according to the BBB scores. At 8 weeks, all the rats were sacrificed and the spinal cords were taken for morphological observation. The spinal cord tissues at the injury site were observed with Brdu nuclear labeling to identify the survival and migration of the transplanted SCs. The regeneration and distribution of the spinal nerve fibers were observed with fluorescent-gold (FG) spinal cord retrograde tracing.</p><p><b>RESULTS</b>Brdu labeling showed that the transplanted hUCB-SCs survived and migrated in the spinal cord 8 weeks postoperatively in groups C and D. FG retrograde tracing identified a small amount of pyramidal cells that migrated across the injury site in groups C and D. The BBB scores of the hindlimb motor function 8 weeks postoperatively were 4.11∓0.14, 4.50∓0.15, 8.31∓0.11 and 11.15∓0.18 in groups A, B, C and D, respectively.</p><p><b>CONCLUSION</b>Lithium chloride can promote the survival and differentiation of hUCB-SCs into neural cells at the injury site. Lithium chloride combined with hUCB-SCs transplantation may accelerate functional recovery of the hindlimbs in rats with complete transection of the spinal cord.</p>

Unilateral pedicle screw fixation plus interbody fusion by Quadrant system through spatium intermuscular of multifidus / 中华外科杂志

<p><b>OBJECTIVE</b>To explore the clinical outcome of unilateral pedicle screw fixation plus single cage interbody fusion through spatium intermuscular of multifidus by Quadrant system.</p><p><b>METHODS</b>From April 2008 to April 2009, 47 patients underwent unilateral pedicle screw fixation plus single cage interbody fusion through spatium intermuscular of multifidus. There were 22 males and 25 females with the mean age of 58.2 years (range, 46-74 years). Among them 12 cases had far-lateral lumbar disc herniation, 7 cases had post-discectomy recurrence, and 28 cases had degenerative instability. Thirty-seven cases were treated with lumbar interbody fusion through transforaminal approach, 10 cases through posterior approach. After surgery, the radiography was carried out to demonstrate the fusion status, and the Nakai criterion was used for assessment.</p><p><b>RESULTS</b>The average skin incision length was 3.2 cm (range, 3.0 to 3.5 cm), the average operative time was 90 min (range, 70 to 160 min), and the average blood loss was 130 ml (range, 90 to 360 ml). All cases were followed up for 8 - 20 months (average 13.6 months). Postoperative radiography showed no evidence of instrument failure, and 43 cases got bone fusion, 4 cases got suspicious fusion. At final followed-up the average leg pain VAS decreased from 7.4 ± 1.1 preoperatively to 2.4 ± 1.3 postoperatively, the average low back pain VAS decreased from 6.7 ± 1.3 preoperatively to 1.8 ± 1.5 postoperatively. According to Nakai criterion, 31 cases were rated as excellent, 11 cases as good, and 5 cases as fair with the total excellent and good rate of 89.4%.</p><p><b>CONCLUSIONS</b>Unilateral pedicle screw fixation plus single cage interbody fusion through spatium intermuscular of multifidus has some advantages of minimal invasiveness, less blood loss, less complications and reliable curative effect. It is a satisfactory lumbar fusion method under suitable indication.</p>

The results of cementless Zweymüller hip system: 5 to 11 years follow-up study / 中华外科杂志

<p><b>OBJECTIVE</b>To analyze the intermediate-term results associated with the use of Zweymtiller hip system.</p><p><b>METHODS</b>Review the 116 cases (142 hips) who were treated with total hip replacement from 1996 to 2002 by a single surgeon using cementless Zweymüller hip systems.</p><p><b>RESULTS</b>Sixty-one cases (77 hips) were followed up, 50 cases (64 hips) were evaluated both clinically and radiographically while 5 cases (6 hips) and 6 cases (7 hips) were only evaluated clinically and radiographically respectively. The average follow-up period was 7.3 years (range 5 to 11 years). The mean preoperative Harris Hip Score was 46 while the mean postoperative Harris Hip Score was 93. Distal cortical hypertrophy and medullary sclerosis were observed in 30 hips (42.3%) and 33 hips (46.5%) respectively. Heterotopic ossification arose in 45 hips (63.4%). Radiolucent lines occurred in 27 stems (38.0%) but in no cups. Radiolucent lines were mostly observed in Gruen zones 1. Osteolysis occurred in 7 cups (9.9%) and 18 stems (25.4%). Osteolysis was mostly observed in Delee Zone 3 and Gruen zone 7. In the distal Gruen zones 3, 4 and 5, no radiolucent line or osteolysis was observed. No hips had been revised, 3 cups needed revision surgery because of aseptic loosening.</p><p><b>CONCLUSION</b>The 5-11 years follow-up results are satisfactory, but osteolysis is common.</p>

The repair of acute spinal cord injury in rats by olfactory ensheathing cells graft modified by glia cell line-derived neurotrophic factor gene in combination with the injection of monoclonal antibody IN-1 / 中华外科杂志

<p><b>OBJECTIVE</b>To research the repair effect of transplantation of glial cell line-derived neurotrophic factor (GDNF) modified olfactory ensheathing cells (OECs) combination with injecting axonal growth inhibiting protein antibody (IN-1) in vivo.</p><p><b>METHODS</b>To construct lentivirus vector with GDNF gene and infect OECs in vitro, use the immunoblotting (Western Blot) to observe the expression of GDNF was detected through Western Blot. Fifty adult female SD rats which to establish thoracic spinal cord transection injury model were randomly divided into A (control group), B (IN-1 antibody group), C (OECs group), D (GDNF-OECs group), and E (GDNF-OECs+IN-1 group) 5 groups of each 10 rats. To observe regeneration of the impaired nerve axon by NF200 immunohistochemistry, Biotinylated dextran amine (BDA) anterograde tracing corticospinal tract. Basso, Beattie and Bresnahan (BBB) score was used to evaluating hindlimb motor function recovery.</p><p><b>RESULTS</b>Add up to 13 rats died post operation. OECs labeled by hoechst still survived and migrated in spinal cord 8 weeks post operation. Lots of confused and disorderly regenerated axons which crossing the injured region of spinal cord were displayed between spinal cord stumps in GDNF-OECs+IN-1 group and GDNF-OECs group; some of axons existed in OECs group, but there is no obviously continue nerve fibers crossing the injured region of spinal cord;in contrast to IN-1 and control groups, few of regenerated axons and atrophy of spinal cord stumps were observed. The results of BBB hindlimb motor rating scale were 7.70+/-0.24, 7.89+/-0.15, 10.50+/-0.25, 11.43+/-0.23 and 12.81+/-0.40 for the control group, IN-1 group, OECs group, GDNF-OECs group and the allied treatment group respectively.</p><p><b>CONCLUSIONS</b>The transplantation of GDNF-OECs combination with IN-1 antibody may benefit the survival and regeneration of the injured axons, and accelerate the repair of the injured spinal cord and functional recover of hindlimb locomotor in rats in a more efficient way than that with OECs or IN-1 alone.</p>

Complications of the anterior surgical approach for thoracolumbar spine tuberculosis: causes and countermeasures / 南方医科大学学报

<p><b>OBJECTIVE</b>To assess the effect of the anterior surgical approach for thoracolumbar spine tuberculosis and analyzed the causes of the surgical complications and the countermeasures.</p><p><b>METHODS</b>From Jan 1996 to Dec 2005, 120 patients with thoracolumbar spine tuberculosis underwent operations through the anterior approach either following the primary diagnosis (115 cases) or for recurrence (5 cases).</p><p><b>RESULTS</b>Intraoperative pleural rupture occurred in 4 cases, and rupture of the external iliac vein occurred 1 case. Three patients had damages of the T12 dorsal ramus. One patient developed venous embolism of the lower extremity after the operation, two had paralytic ileus and 1 had false diabetes insipidus. Of the 5 recurrent patients, 1 died due to alcoholic cirrhosis and acute liver failure, 1 received a third operation for loosened internal fixation, and 1 had recurrence due to extensive drug resistance (XDR).</p><p><b>CONCLUSION</b>Standardized antituberculous therapy is fundamental for preventing the recurrence of tuberculosis, and individualized antituberculous therapy adjustment according to the results of bacterial culture and drug sensitivity tests can be the most effective means for preventing drug resistance and reducing tuberculosis recurrence.</p>

Risk factors of secondary kyphotic angle increment after veterbroplasty for osteoporotic vertebral body compression fractures / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the risk factors of secondary kyphotic angle increment after bone cement vertebroplasty for osteoporotic vertebral compression fractures.</p><p><b>METHODS</b>From October 2005 to May 2006, 32 (45 vertebrae) bone cement vertebroplasty procedures were performed. The operation time, injected cement volume, bone mineral density, visual analog scale (VAS) pain score, vertebral height, and kyphotic angle were recorded. The secondary increment of the kyphotic angle was calculated, and correlation analysis and linear regression analysis were performed.</p><p><b>RESULTS</b>The bone mineral density, the postoperative kyphotic angle and the vertebral midline height were significantly correlated to the secondary increment of the kyphotic angle.</p><p><b>CONCLUSION</b>Large postoperative kyphotic angle, poor postoperative recovery of the vertebral midline height, and low bone mineral density are all risk factors of secondary increment of the kyphotic angle.</p>

Comparative study of dynamic fixation with rigid fixation in the management of degenerative lumbar spondylosis / 中华外科杂志

<p><b>OBJECTIVE</b>To compare the clinical effects of dynamic fixation and rigid fixation in the management of degenerative lumbar spondylosis.</p><p><b>METHODS</b>The hospitalized patients with degenerative lumbar spondylosis, including degenerative lumbar instability, lumbar spondylolisthesis and lumbar stenosis from January 2002 to December 2006 formed the subjects of our study. According to the inclusion criteria, 100 patients (male 58, female 42) were selected. The cases were divided into rigid fixation group (A) and dynamic fixation group (B), with 50 cases in each. The average age was (56 +/- 6) years old of group A, and (57 +/- 9) years old of group B. Standing plain radiography, computerized tomography (CT) or magnetic resonance imaging (MRI) were taken in all the cases. The observation index included incidence of adjacent segment degeneration (ASD), breakage of implant, fusion rate, lumbo-pelvic parameters and visual analogue scales (VAS) scores.</p><p><b>RESULTS</b>Six cases developed ASD in group A (12.0%), and 1 case in group B (2%). Implant breakage happened in 2 cases in group A (4.0%), while none in group B. There was 1 case of pseudo-articular formation in group A (2.0%), but none in group B. Lumbar lordosis (LL) was corrected with (14.2 +/- 2.2) degrees in group A, and (20.2 +/- 3.7) degrees in group B (P = 0.031). Sacral slope (SS) was corrected with (12.6 +/- 4.3) degrees in group A and (15.8 +/- 6. 5) degrees in group B (P = 0.052). Pelvic tilt (PT) was corrected with (8.3 +/- 2.7) degrees in group A and (4.5 +/- 2.2) degrees in group B (P = 0.014). Pelvic incidence was corrected with (2.0 +/- 0.1) degrees in group A and (0.9 +/- 0.1) degrees in group B (P = 0.008). The VAS score decreased significantly in both groups within the first 2 years after operation. But as time going, the patients with rigid fixation felt pain gradually, and the pain was more severe than in patients with dynamic fixation.</p><p><b>CONCLUSION</b>Dynamic fixation could prevent ASD and implant failure effectively.</p>

Effect of prosthetic nucleus pulposus replacement on stress distributions of lumbar disc endplate / 中华外科杂志

<p><b>OBJECTIVE</b>To determine the stress distribution on endplate after lumbar prosthetic disc nucleus (PDN) replacement.</p><p><b>METHODS</b>Six fresh lumbar vertebrae with normal Modic classification were harvested. The specimens were used to establish L4-5 intact, nucleotomy, prosthetic nucleus pulposus replacement models. Vertical compression tests were performed with MTS machine at the rate 50 N per second to maximum load of 1300 N. The stress under the endplate were measured directly with accurate pressure sensors.</p><p><b>RESULTS</b>For intact specimens, the stress on the endplate maintained higher in the central zone of the endplate, and decreased gradually to the periphery, and was well-distributed. After nucleotomy, the stress on the central zone of endplate was significantly decreased, and increased stress occurred in the periphery of endplate. After PDN replacement, the stress on the central zone of endplate was found more 15.1% higher than that in intact disc (P < 0.05), and the neighboring zone also showed higher stress measurements.</p><p><b>CONCLUSIONS</b>After lumbar prosthetic disc nucleus replacement, the stress concentration on endplate may occur in the central zone of prosthetic disc nucleus insertion. Therefore, the prosthetic nucleus pulposus with suitable shape, proper biomechanical functions and updated materials need further study.</p>

Prokaryotic expression and bioactivity of human platelet-derived growth factor B chain mature peptide / 南方医科大学学报

<p><b>OBJECTIVE</b>To express human platelet-derived growth factor (hPDGF) B chain mature peptide gene in a prokaryotic expression system and detect the bioactivity of the expressed protein.</p><p><b>METHODS</b>hPDGF B chain mature peptide gene was amplified and expressed in E. coli, and the recombinant protein, rhPDGF-BB, was purified and renatured in GSSG/GSS system. The bioactivity of rhPDGF-BB in vitro was evaluated with SD rat osteoblasts.</p><p><b>RESULTS</b>The full-length PDGF-B mature peptide gene was obtained and verified, and successfully expressed in E. coli. Bioactivity detection results showed that the expressed rhPDGF-BB obviously promoted the proliferation and DNA replication of SD rat osteoblasts in vitro (P<0.01).</p><p><b>CONCLUSION</b>he PDGF-B chain mature peptide cDNA has been successfully cloned and the PDGF-B precursor highly expressed in E. coli, and renatured rhPDGF-BB displays high bioactivity as shown by MTT assay and flow cytometry. This success provides the basis for production of functional PDGF-BB and facilitates further studies of its role in fracture healing and trauma reconstruction.</p>