Objective To investigate the stability and the stress distributions of L3-5 fused with three different approaches (interbody, posterolateral and circumferential fusions) and to investigate degeneration of thesegment adjacent to the fused functional spinal unit. Methods A detailed L3-5 three-dimensional nonlinear finite element model of a normal man aged 32 was established and validated. Based on the model, the destabilized model, the interbody, posterolateral and circumferential fusions models of L4-5 were established. After the loadings were placed on all the models, we recorded the angular motions of the fused segment and the Von Mises stress of the adjacent intervertebral disc. Results The circumferential fusion was most stable than the others, and the interbody fusion was more stable than the posterolateral fusion. The maximal Von Mises stress of the adjacent L3,4 intervertebral disc in all the models was ranked descendingly as flexion,lateral bending,torsion and extension. For the three kinds of fusions, the stress increment of the L3,4 intervertebral disc was ranked ascendingly as interbody fusion,posterolateral fusion and circumferential fusion. Conclusion After destabilization of the L4,5 segment, the stability of the circumferential fusionis better than that of the others, particularly under the flexional or extensional loading. The stability of the interbody fusion is better than that of the posterolateral fusion, except for under the flexional loading. The feasibility of adjacent segment degeneration can be ranked descendingly as: circumferential fusion,posterolateral fusion and interbody fusion.
OBJECTIVE To investigate the therapeutic effect of percutaneous lumbar discectomy (PLD) combined with sodium hyaluronate (SH) injection in the treatment of lumbar intervertebral disc herniation. METHODS Forty-eight patients suffered from lumbar disc herniation were divided into two groups and treated by PLD combined with SH injection into epidural cavity (treatment group) or single PLD (control group) respectively. All patients were followed up for 24 months. The therapeutic effects in both groups were assessed and compared according to Macnab’s criterion. RESULTS The patients in the treatment group got much more significant improvement than those in the control group, with shorter therapeutic course and more safety. CONCLUSION PLD combined with SH injection into epidural cavity is more effective and safety in the treatment of lumbar disc herniation than of pure PLD.
ObjectiveTo compare the clinical and radiological effectiveness of oblique lumbar interbody fusion (OLIF) and posterior lumbar interbody fusion (PLIF) in the treatment of Cage dislodgement after lumbar surgery.MethodsThe clinical data of 40 patients who underwent revision surgery due to Cage dislodgement after lumbar surgery betweem April 2013 and March 2017 were retrospectively analyzed. Among them, 18 patients underwent OLIF (OLIF group) and 22 patients underwent PLIF (PLIF group) for revision. There was no significant difference between the two groups in age, gender, body mass index, intervals between primary surgery and revision surgery, number of primary fused levels, disc spaces of Cage dislodgement, and visual analogue scale (VAS) scores of low back pain and leg pain, Oswestry disability index (ODI), the segmental lordosis (SL) and disc height (DH) of the disc space of Cage dislodgement, and the lumbar lordosis (LL) before revision (P>0.05). The operation time, intraoperative blood loss, hospital stay, and complications of the two groups were recorded and compared. The VAS scores of low back pain and leg pain were evaluated at 3 days, 3, 6, and 12 months after operation, and the ODI scores were evaluated at 3, 6, and 12 months after operation. The SL and DH of the disc space of Cage dislodgement and LL were measured at 12 months after operation and compared with those before operation. CT examination was performed at 12 months after operation, and the fusion of the disc space implanted with new Cage was judged by Bridwell grading standard.ResultsThe intraoperative blood loss in the OLIF group was significantly less than that in the PLIF group (t=?12.425, P=0.000); there was no significant difference between the two groups in the operation time and hospital stay (P>0.05). Both groups were followed up 12-30 months, with an average of 18 months. In the OLIF group, 2 patients (11.1%) had thigh numbness and 1 patient (5.6%) had hip flexor weakness after operation; 2 patients (9.1%) in the PLIF group had intraoperative dural sac tear. The other patients’ incisions healed by first intention without early postoperative complications. There was no significant difference in the incidence of complications between the two groups (χ2=0.519, P=0.642). The VAS scores of low back pain and leg pain, and the ODI score of the two groups at each time point after operation were significantly improved when compared with those before operation (P<0.05); there was no significant difference between the two groups at each time point after operation (P>0.05). At 12 months after operation, SL, LL, and DH in the two groups were significantly increased when compared with preoperative ones (P<0.05); SL and DH in the OLIF group were significantly improved when compared with those in the PLIF group (P<0.05), and there was no significant difference in LL between the two groups (P>0.05). CT examination at 12 months after operation showed that all the operated disc spaces achieved bony fusion. According to the Bridwell grading standard, 12 cases were grade Ⅰ and 6 cases were grade Ⅱ in the OLIF group, and 13 cases were grade Ⅰ and 9 cases were grade Ⅱ in the PLIF group; there was no significant difference between the two groups (Z=–0.486, P=0.627). During follow-up, neither re-displacement or sinking of Cage, nor loosening or fracture of internal fixation occurred.ConclusionOLIF and PLIF can achieve similar effectiveness in the treatment of Cage dislodgement after lumbar surgery. OLIF can further reduce intraoperative blood loss and restore the SL and DH of the disc space of Cage dislodgement better.
OBJECTIVE: To investigate the effects of nerve root compression on dorsal root ganglia. METHODS: Following the method of Kawakami, 4/0 ribbon gut were applied around left L4-6 spinal nerve roots in 50 SD rats. Just 3 mm cranial to the dorsal root ganglia, the nerve roots were secured by two ligation node. The nerve roots of right side were as control. The L4-6 spinal cord was taken out 1, 2, 4, 8, 12 weeks after surgery, respectively. The activity of fluoride resistant acid phosphatase (FRAP) was determined by the enzyme histochemistry (Gomori method) and the image analysis technique. RESULTS: In the test side, the FRAP content of spinal dorsal horn reduced 4 weeks after operation. And there were gradually more and more decreases from 4 to 12 weeks. There was significant difference between the test side and control side (P lt; 0.01). CONCLUSION: Chronic nerve root compression causes damage to dorsal root ganglia.
Objective To evaluate the cl inical effect of local autogenous bone chips extended with allogeneic bone grafts in the posterolateral lumbar fusion. Methods From March 2005 to April 2007, 22 cases which underwent posterolaterallumbar fusion with allograft bone mixed with local autograft bone were analyzed retrospectively. The postoperative temperature, drainage flow and heal ing time of the incision were analyzed; postoperative lumbar pain was evaluated by visual analog scale (VAS) and JOA score; the postoperative efficacy was assessed by MacNab criteria and Oswestry disabil ity index (ODI); the fusion rate was defined by Jorgenson fusion criteria. Results All cases were followed up for 17-35 months with an average of 21 months, the wound all healed by first intention; no red swell ing, exudation and infection occurred. The excellent and good rate was 81.8% for JOA score (excellent in 4 cases, good in 14 cases, fair in 4 cases), 77.3% for MacNab criteria (excellent in 4 cases, good in 13 cases, fair in 5 cases) and 90.9% for ODI index (excellent in 3 cases, good in 17 cases, fair in 2 cases). The postoperative X-ray fusion rate within 1 year was 90.9%. Conclusion Allograft bone mixed with local autograft bone can achieve good efficacy and fusion rate in posterolateral lumbar fusion.
Objective To evaluate the clinical outcomes ofa surgical approach for decompression of lumbar spinal stenosis, which was featured with reconstruction of posterior spinal structures and epidural space by spinous process-splitting, less osteotomy, laminar flap and keeping spinal process, lamina, outer ligmentum flavum intact. Methods From October 2001 to April 2003, 39 patients (19 males and 20 females, aging 36 to 77 years with a mean age of 49.6 years with lumbar stenosis underwent the surgical decompression procedure with reconstruction of posterior canal structures and epidural space. The involved locations were L3,4 to L5S1(5 cases),L4,5 to L5S1(18 cases), L4,5(11 cases) and L5S1(5 cases). The course of disease was 3 months to 16 years (40.4 months on average). The clinical outcomes after 1 year of operation Results All patients were followed up from 18 to 36 months. No intraoperative and postoperative complications were observed and all patients were satisfactory with the surgery. Computerized tomography showed that spinal and nerve root canal were satisfactorily enlarged 1 week postoperatively in all cases. Fusion of lamina and spinous process were detected on CT in 87.2% patients (34/39) 3 months after operation. No patients presented re-stenosis of lumbar spine and all patients presented bony fusion 1 year after surgery. Conclusion The approach of the current study was a reliable and effective method in the management of lumbar stenosis, it preserved thecontinuity of spinal process, interspinous ligaments, lamina and ligmentumn flavum and integrality of posterior spinal structures and epidural space. The integrity of the psoterior spinal structures can prevent the scar formation and improve the stability of lmbar spine postoperatively.
ObjectiveTo systematically review the effectiveness and safety of dynamic neutralization system (Dynesys) versus posterior lumbar interbody fusion (PLIF) for lumbar degenerative disease.
MethodsDatabases including PubMed, EMbase, The Cochrane Library (Issue 5, 2016), CNKI, CBM, VIP and WanFang Data were searched to collect studies about Dynesys versus PLIF for lumbar degenerative disease from inception to May 31st 2016. Two reviewers independently screened literature, extracted data, and evaluated the methodological quality of included studies. Then, meta-analysis was performed using RevMan 5.3 software.
ResultsA total of 22 studies involving 1 482 patients were included. The results of meta-analysis showed that, compared with PLIF, Dynesys could reduce operative time (MD=-29.62, 95%CI -36.67 to -22.57), operative blood loss (MD=-112.10, 95%CI -130.60 to -93.61), length of hospital stay (MD=-2.62, 95%CI -4.96 to -0.28), postoperative adjacent segment ROM (MD=-1.29, 95%CI -1.72 to -0.86) and maintain postoperative operated segment ROM (MD=3.53, 95%CI 1.99 to 5.08). There were no significant differences between two groups in postoperative ODI (MD=-1.51, 95%CI -3.58 to 0.55), postoperative back VAS (MD=-0.15, 95%CI -0.38 to 0.08), postoperative leg VAS (MD=-0.09, 95%CI -0.22 to 0.04) and postoperative complications (OR=0.69, 95%CI 0.45 to 1.06).
ConclusionThe current evidence shows that compared with PLIF, Dynesys for lumbar degenerative disease has shorter operative time, less operative blood loss, shorter hospitalization days, and Dynesys can also maintain operated segment ROM and delay the degeneration of adjacent segment. Due to the limited quality of the included studies, more studies are needed to verify the above conclusion.
Objective To analyze the therapeutic effect of the posterior pedicle screw system combined with interbody fusion cage on lumbarspondylolisthesis. Methods From February 2003 to March 2006, 37 lumbar spondylolisthesis patients were treated with this operation, including21 males and 16 females and aging 3969 years.The affected lumbars were L3(3cases)，L4(23 cases), and L5(11 cases). According to the Meyerdingevaluating system, 12 cases were lassified as degree Ⅰ, 20 cases as degree Ⅱ,and 5 cases as degree Ⅲ. Taillard index, Boxall index, slipping angle, lumbar lordosis angle and intervertebral height index were measured before operation, and 2 weeks and 3 months after operation. Results All patients were followed up 336 months. There were statistically significant differences in Taillard index, Boxall index, slipping angle, lumbar lordosis angle and intervertebral height index between before operation and 2 weeks after operation (P＜0.05),and no statistically significant differences between 2 weeks and 3 months afteroperation(P＞0.05). According to Dewei Zhou’s creterior for scoring, the results were excellent in 27 cases， good in 8 cases，and fair in 2 cases. Theexcellent and good rate was 94.6%. All of the embedded osseous were fused. Thefusing time was from 3 to 8 months (mean 3-9 months). There were no breakageof screw and rod. The position and configuration of the whole cages were good. Conclusion Applying the posterior pedicle screw system combined with interbody fusion cage may achieve synergism in the treatment of lumbar vertebral spondylolisthesis. Above procedure is served as solid internal fixationand offers a satisfactory reduction, and can improve the fusion rate of the spine. So it is an ideal procedure and worthily recommended method for treatment oflumbar vertebral spondylolisthesis.
Objective To evaluate lumbar laminotomy and replantation in prevention of spinal unstability and peridural adhesion after laminectomy.Methods From February 1995 to March 2001,a total of 169 patients(96 males, 73 females,aged 22-63) with lesions in the lumbar vertebral canals underwent surgery, in which the lesions were removed afterlaminectormy and then the excised laminae were replanted. Results The follow-up for 5-9 years showed that all the patients had no complications after the lesions were removed. According to the evaluation criteria formulated by WANG Yongti，81 patients had an excellent result, 67 had a good result, 19 had a fair result, and2 had a poor result. 87.6% of the patients obtained quite satisfactory results.The X-ray films demonstrated that the replanted laminae obtained bony healing and the spine was stable. The CT scanning demonstratedthat the canals were enlarged with a smooth and glossy interior. Conclusion Lumbar laminotomy and replantation is reasonable in design and convenient in performance, which can be promoted as a basic operation in spinal surgery.
The lumbar intervertebral disc exhibits a complex physiological structure with interactions between various segments, and its components are extremely complex. The material properties of different components in the lumbar intervertebral disc, especially the water content (undergoing dynamic change as influenced by age, degeneration, mechanical loading, and proteoglycan content) - critically determine its mechanical properties. When the lumbar intervertebral disc is under continuous pressure, water seeps out, and after the pressure is removed, water re-infiltrates. This dynamic fluid exchange process directly affects the mechanical properties of the lumbar intervertebral disc, while previous isotropic modeling methods have been unable to accurately reflect such solid-liquid phase behaviors. To explore the load-bearing mechanism of the lumbar intervertebral disc and establish a more realistic mechanical model of the lumbar intervertebral disc, this study developed a solid-liquid biphasic, fiber-reinforced finite element model. This model was used to simulate the four movements of the human lumbar spine in daily life, namely flexion, extension, axial rotation, and lateral bending. The fluid pressure, effective solid stress, and liquid pressure-bearing ratio of the annulus fibrosus and nucleus pulposus of different lumbar intervertebral discs were compared and analyzed under the movements. Under all the movements, the fluid pressure distribution was closer to the nucleus pulposus, while the effective solid stress distribution was more concentrated in the outer annulus fibrosus. In terms of fluid pressure, the maximum fluid pressure of the lumbar intervertebral disc during lateral bending was 1.95 MPa, significantly higher than the maximum fluid pressure under other movements. Meanwhile, the maximum effective solid stress of the lumbar intervertebral disc during flexion was 2.43 MPa, markedly higher than the maximum effective solid stress under other movements. Overall, the liquid pressure-bearing ratio under axial rotation was smaller than that under other movements. Based on the solid-liquid biphasic modeling method, this study more accurately revealed the dominant role of the liquid phase in the daily load-bearing process of the lumbar intervertebral disc and the solid-phase mechanical mechanism of the annulus fibrosus load-bearing, and more effectively predicted the solid-liquid phase co-load-bearing mechanism of the lumbar intervertebral disc in daily life.
