In order to investigate the mechanical response of lumbar vertebrae during gait cycle in adolescents with idiopathic scoliosis (AIS), the present study was based on computed tomography (CT) data of AIS patients to construct model of the left support phase (ML) and model of the right support phase (MR), respectively. Firstly, material properties, boundary conditions and load loading were set to simulate the lumbar vertebra-pelvis model. Then, the difference of stress and displacement in the lumbar spine between ML and MR was compared based on the stress and displacement cloud map. The results showed that in ML, the lumbar stress was mostly distributed on the convex side, while in MR, it was mostly distributed on the concave side. The stress of the two types of stress mainly gathered near the vertebral arch plate, and the stress of the vertebral arch plate was transmitted to the vertebral body through the pedicle with the progress of gait. The average stress of the intervertebral tissue in MR was greater than that in ML, and the difference of stress on the convex and convex side was greater. The displacement of lumbar vertebrae in ML decreased gradually from L1 to L5. The opposite is true in MR. In conclusion, this study can accurately quantify the stress on the lumbar spine during gait, and may provide guidance for brace design and clinical decision making.
Objective To elucidate the new development, structural features and appl ication of the lumbar interspinous process non-fusion techniques. Methods With the review of the development course and important research works in the field of the lumbar inter-spinous process non-fusion techniques, the regularity summary, science induction, and prospect were carried out. Results The lumbar inter-spinous process non-fusion technique was a part of non-fusion insertof spinal division posterior surface. According to the design, it could be divided into two major categories: dynamic and static systems. The dynamic system included Coflex and device for intervertebral assisted motion; the static system included X-STOP, ExtenSure and Wall is. The lumbar inter-spinous process non-fusion technique was a new technique of spinal division, it could reserve the integrated function of intervertebral disc and zygapophysial joint, maintain or recover the segmental movement to a normal level, and have no adverse effect on the neighboring segments. A lot of basic and cl inical researches indicated that lumbar inter-spinous process insert had extensive appl ication to curatio retrogression lumbar spinal stenosis, discogenic low back pain, articular process syndrome, lumbar intervertebral disc protrusion and lumbar instabil ity and so on. Conclusion With the matures of lumbar inter-spinous process non-fusion techniques and the increased study of various types of internal fixation devices, it will greatly facil itate the development of treatment of lumbar degenerative disease. But long-term follow-up is needed to investigating the long-term efficacy and perfect operation indication.
ObjectiveTo isolate nucleus pulposus cells (NPCs) from the caudal and lumbar intervertebral disc of rat, and to identify the morphology and to compare the characteristics. MethodsThe whole spine was separated from 8-week-old Sprague Dawley rats under the sterile conditions. NPCs of different segments (lumbar group: L1,2-L6, S1; caudal group: C1,2-C17,18) were cultured by adherent cultivation approach. Cellular morphologic change was noted by HE staining and continuous observation under inverted phase contrast microscope. Besides, the aggrecan and collagen type Ⅱexpression were examined by toluidine blue and immunocytochemistry staining respectively. The total protein contents, senescence level, and the cell viability of passage 1-5 (P1-5) were detected. The growth curves of the P1 cells in lumbar and caudal groups were determined by cell counting kit 8. ResultsThe NPCs were isolated and identified successfully. The adherence time of the primary cells (the cell fusion reached 90%) in lumbar group was significantly longer than that in caudal group in primary generation (P<0.05). HE staining showed that cytoplasm was pink with the blue nucleus. Lumbar disc NPCs were spindle. The larger caudal disc NPCs were polygonal or irregular. Toluidine blue staining showed that the proteoglycan was stained as blue. In the cytoplasm of cells, collagen type Ⅱwas stained as brown surround the blue-black nucleus. The cell viability had no significant difference between lumbar and caudal groups and between different passages in the same group (P>0.05). The caudal disc NPCs reached their logarithmic growth phase after 3 days of culture, while the cells in lumbar segments did after 4-5 days of culture. The cell proliferation in caudal segments was more than that in lumbar segments at 3-9 days (P<0.05). The difference in the total protein contents was not significant between cells at P1-5 in 2 groups (P>0.05), and the caudal disc NPCs had higher protein contents than lumbar disc NPCs (P<0.05). There was no significant difference in cell senescence rate between cells at P1, P2, and P3 in 2 groups (P>0.05), but significant difference was shown in senescence rate between 2 groups in cells at P4 and P5 (P<0.05). ConclusionCaudal disc NPCs have a better status, which is more suitable for experiment as a seed cell than the lumbar disc NPCs in the same generation.
Objective To investigate the cl inical appl icabil ity and value of internal fixator for the reconstruction of lumbar isthmus in the treatment of lumbar vertebral spondylolysis and to lay a fundation for its cl inical appl ication. Methods Sixteen healthy goats weighing 22.65-31.22 kg were selected to establ ish the models of vertebral spondylolysis at L5, which thereafter were randomized into two groups (n=8): bone graft group in which 0.8-1.1 g fresh autogenous bone was transplanted into the isthmus spondylolysis area, and internal fixation with bone graft group in which internal fixator was installed before transplanting 0.8-1.1 g fresh autogenous bone into the isthmus spondylolysis area. All animals were killed 8 weeks after operation to receive imaging, topographic anatomy and histology detection. Meanwhile, biomechanics test was performed by using 5 donated vertebral body specimens (4 males and 1 female aged 35-51 years old). The left isthmus of L5 vertebra was transected to serve as lumbar vertebral spondylolysis model. A mini-displacement sensor was put at the transected ends of the isthmus. Then loading was conducted with a constant velocity of 2 mm/min by electronic omnipotent tester simulating the direction of fixation force of the internal fixator, and the deformation value of the transected ends was collected by a dynamic data collector and analyzer. The loading wascontinued until the vertebra specimens were damaged. The deformation of displacement sensor and the closure of transected ends of the lumbar isthmus were observed. Results All the goats behaved normally shortly after operation, and no nerve injury induced by operation and no wound infection occurred. Bilaterally obl ique X-ray films of lumbar vertebra and topographic anatomy 8 weeks after operation showed the fusion rate of the internal fixation and bone graft group and the bone graft group was 100% and 62.5%, respectively, indicating there was a significant difference (P lt; 0.05). Histology observation showed 3 goats in the bone graft group presented empty bone trabecula, empty bone lacuna and the disappearance of osteocytes at the transected ends of lumbar isthmus; while in the internal fixation and bone graft group, the bone trabecula grew into cancellous structures with hematopoietic and fatty bone marrow tissue inside, and parts of the bone trabecula had various degrees of mosaic-l ike pattern. During the upload, the biomechanics test and data processing results showed when the external load was 40 N, the deformation of displacement sensor was identified and the gap between the transected ends of lumbar isthmus started to close; then with the increase of external load, the displacement sensor tended to ascend in a l inearity manner; while when the external load was 212 N, the displacement sensor had no further deformation, the gap between the transected ends of lumbar isthmus wascompletely closed, and the pressor effect appeared. Conclusion The internal fixator for the reconstruction of lumbar isthmus has mechanical effects of stabil izing and elevating pressure with a high fusion rate.
Objective To review the research progress of stress fracture of the lumbar pedicle. Methods The literature about the stress fracture of the lumbar pedicle was reviewed extensively and summarized. Results There are two types of stress fracture: fatigue and structure insufficient. Stress fracture of lumbar pedicle occurred mainly in the crowd with repetitive and large activities of spine, contralateral spondylolysis, or previous surgery of lumbar vertebra. The main stresses causing stress fracture of the lumbar pedicle are shear stress and twisting stress, followed by sudden hyperflexion or hyperextension of the spine. Stress fracture of lumbar pedicle was easily missed by conventional X-ray examination, usually XCT, MRI, or bone scan was needed to confirm the diagnosis. It is divided into 4 types or 4 periods according to MRI findings: stress reaction, incomplete fracture, complete fracture, and pseudarthrosis. For patients with incomplete, complete, and juvenile stress fractures of the lumbar pedicle without nerve root irritation, the majority of claims preferred conservative treatment and the healing rate of fracture was high; for patients with bilateral pseudarthrosis and with nerve root irritation as well as patients who failed to the conservative treatment, surgical management was advocated and the operation result is good. Conclusion Stress fracture of the lumbar pedicle as one of the causes of low back pain is extremely rare, and is easily missed clinically. Surgery or conservative management should be selected based on type of fracture and specific condition of the patient, the treatment results are satisfactory.
ObjectiveTo review the researches of in vivo kinematics in lumbar degenerative spondylol isthesis (DS). MethodsRelated literature concerning the in vivo kinematics in patients with lumbar DS was extensively reviewed and comprehensively analyzed in 4 terms of the instabil ity of lumbar DS, vertebral motion pattern, the morphological changes of spinal canal, and intraoperative biomechanical measurement. ResultsWhether there is lumbar segmental instabil ity in lumbar DS patients is still controversial, which should be based on degenerative stage of lumbar spine and grade of slip. The hypomobility of the lumbar spinous processes and the facet joint is seen in DS. The diameter, cross-sectional area, and volume of spinal canal in lumbar DS patients are significantly smaller than those of the normal control. Because of its invasive procedure and medical ethics, the use of the intraoperative measurement device is limited. These reported researches of in vivo kinematics in DS are almost on the sagittal plane. However, few data have been reported on the 6-degree-of-freedom (6DOF) kinematics of the diseased levels under physiological loading conditions. ConclusionThe 6DOF kinematics data can accurately reflect the segmental motion characteristics in lumbar DS patients, recent studies have been reported, further studies are still needed.
Objective To explore the feasibil ity and efficacy of percutaneous kyphoplasty (PKP) for the treatment of severe osteoporotic vertebral compression fracture (OVCF), and to assess the cl inical result of the PKP technique. Methods From May 2006 to October 2007, 12 patients with severe OVCF affecting more than 2/3 of the original vertebral body height were treated by using domestic PKP and percutaneous vertebroplasty (PVP) tool systems. There were 3 malesand 9 females, with the age of 56-82 years and a mean disease course of 4.2 months (1-49 months). Eleven thoracic vertebra and 4 lumbar vertebra suffered from severe vertebral compression fractures, which included 3 extremely severe thoracic OVCF. Four thoracic vertebra and 3 lumbar vertebra had not severe OVCF. There were 4 cases of single vertebral compression fracture, 6 cases of double fractures, and 2 cases of triple fractures. Only single side PKP and PVP were performed via extrapedicular approach in thoracic vertebra, and via transpedicular approach in lumbar spine under fluoroscopic control. Eight patients with severe thoracic compression fractures and 4 with severe lumbar fractures were treated by PKP. Four patients with relatively mild thoracic compression fractures and 3 with lumbar fractures were treated by PVP. Results The operation was successfully, 3 patients with extremely severe thoracic compression fractures received no intervention. The maximum expansion pressure of balloon was (1 068 ± 298) kPa, and the volume was (3.1 ± 1.2) mL during operation. The average operative time of PKP was (44.9 ± 10.6) minutes per vertebra, while the average operative time of PVP was (36.5 ± 6.8) minutes per vertebra. The average volume of injected bone cement was (2.5 ± 0.6) mL per thoracic vertebra, and (3.6 ± 1.2) mL per lumbar vertebra. The mean hospitalization time were (3.7 ± 1.6) days. Twelve cases were followed up 5-18 months (mean 8.6 months). The visual analogue scale scoreswere (2.35 ± 0.61) points 2 days after operation and (2.89 ± 1.07) points at last follow-up, there were statistically significant differences when compared with before operation (8.27 ± 1.36) points (P lt; 0.01). Extravertebral leakage of the bone cement into the paravertebral tissue and/or disc occurred in 6 patients (9 vertebra) without significant symptom. Conclusion One side approach PKP is a safe and effective technique for treatment of severe OVCF with markedly rel ief of pain.
Objective To evaluate the mid-term cl inical outcome of instrumented sl ip reduction combined with 360° circumferencial fusion and restoration laminae for symptomatic adult isthmic spondylol isthesis. Methods Between October 2004 and March 2008, 44 patients with symptomatic isthmic spondylol isthesis underwent instrumented sl ip reduction combined with 360° circumferencial fusion and restoration laminae. There were 15 males and 29 females with an average age of38.4 years (range, 28-45 years). The disease duration was 14 months to 7 years (38 months on average). The affected vertebrae was L4-5 in 18 patients and L5, S1 in 26 patients. According to Meyerding’s grade for spondylol isthesis, 28 cases were rated as grade II and 16 as grade III. The visual analogae scale (VAS), Oswestry disabil ity index (ODI), and the short form 36 health survey (SF-36) scores were evaluated before operation and at last follow-up; the radiographical outcome was evaluated by measuring sl i pping percentage, heights of intervertebral space and foramen, and fusion rate. Results All patients were followed up 20-60 months (42 months on average). The VAS, ODI, and SF-36 scores were all significantly improved at last follow-up when compared with those before operation (P lt; 0.05). According to Morelos criteria, the cl inical results were excellent in 32 patients, good in 9, and fair in 3; the excellent and good rate was 93.2%. The preoperative average percentage of sl ip was 47.5%, which was improved to 2.6% 3 days after operation; the total average reduction rate was 97.4%, and it was maintained at last followup. The heights of intervertebral space and foramen were all improved significantly after operation (P lt; 0.05), and there was no significant difference between at 3 days after operation and at last follow-up (P gt; 0.05). X-ray and CT showed bony fusion 1 year after operation in all patients with a fusion rate of 100%. Compl ications included pain at donor site of il iac bone in 4 cases, superficial infection in 2 cases, dural tear in 1 case, and degeneration of adjacent vertebrae in 2 cases; no nerve root injury, pseudoarthrosis, failure of internal fixation, and acquired spinal canal stenosis occurred. Conclusion Instrumented sl ip reduction combined with 360° circumferencial fusion and restoration laminae is a rel iable procedure for adult isthmic spondylol isthesis with satisfactory mid-term results, a high fusion rate and low compl ication rate. The long-term outcomesshould be verified by follow-up in the future.
ObjectiveTo analyze the relative position between lumbar plexus and access corridor of minimally invasive lateral transpsoas approach based on magnetic resonance imaging distribution of lumbar plexus by three dimensional reconstruction technique, so as to evaluate approach safety. MethodsThree-dimensional fast imaging employing steady-state acquisition sequences of lumbar spine were performed on 71 patients with lumbar degenerative diseases between July 2012 and January 2015. The axial image distance between the anterior edge of lumbar plexus and sagittal central perpendicular line (SCPL) of disc was determined using the distance formula at the mid-disc space from L1, 2 to L4, 5 level. SCPL was drawn perpendicularly to the sagittal plane of intervertebral disc and it passed through its central point, which is initial dilator trajectory for transpsoas approach. With respect to the SCPL of disc, the distance with a positive value indicated neural tissue posterior to it whereas anterior to it represented by a negative value. ResultsVarious branches of lumbar plexus which passed through the psoas major anterior to the SCPL of disc were identified in 42 (59.2%), 58 (81.7%), and 70 (98.6%) patients at L2, 3, L3, 4, and L4, 5 levels, respectively. It is possible to infer the presence of genitofemoral nerve in accordance with relevant anatomic research. A ventral migration of intrapsoas nerves is identified from L1, 2 to L4, 5 level. All differences between levels were statistically significant (P < 0.05). ConclusionWith respect to the SCPL of disc, a pass way of guide wire or a radiographic reference landmark to place working channel, lumbar plexus lie posterior to it from L1, 2 to L3, 4 level and shift anteriorly to it at L4, 5 level, while genitofemoral nerve locate anterior to the SCPL from L2, 3 to L4, 5 level. Neural retraction may take place during sequential dilation of working channel especially at L4, 5 level.
ObjectiveTo analyze the relationship between the bone mineral density (BMD) and lumbar intervertebral disc degeneration in rhesus macaques by using T1ρ-MRI. MethodsTwenty female rhesus macaques at the age of 10.9 years on average (rang, 4-20 years) were selected. The lumbar intervertebral discs were classified by Pfirrmann grading system and the T1ρ relaxation time (T1ρ value) was examined by using MRI (Philips 1.5 Tesla), and then BMD values of the L4,5 vertebrae and femoral ward's triangle were detected by using Osteocore dual energy X-ray absorptiometry. Finally, the relationship of T1ρ value of the lumbar intervertebral discs and Pfirrmann grading with age, weight, BMD of lumbar vertebrae and femoral ward's triangle was analyzed. ResultsThe BMD values of lumbar vertebrae and femoral ward's triangle were (0.64±0.17) g/cm2 and (0.67±0.19) g/cm2 respectively, showing no significant difference (t=2.893, P=0.128). According to Pfirrmann grading system, there were 7 cases of grade I, 8 cases of grade Ⅱ, and 5 cases of grade Ⅲ at L4,5 intervertebral discs. The T1ρ value of the lumbar intervertebral disc was (104.08±18.65) ms; the T1ρ values of grades I, Ⅱ, and Ⅲ were (121.31±13.44), (104.73±15.01), and (77.41±11.87) ms, respectively. There was a negative correlation between T1ρ value and the age and the BMD of lumbar vertebrae and femoral ward's triangle. There was a positive correlation between Pfirrmann grading and the variables as listed above. Significant negative linear correlation was also observed between T1ρ value and Pfirrmann grading. ConclusionThe T1ρ value is a reliable index when quantifying lumbar intervertebral disc degeneration, and there is a significant positive correlation between BMD and lumbar intervertebral disc degeneration in rhesus macaques.