The purpose of this study is to reveal the protective effect of rib cage on scoliotic spine by comparing the different effect of rib cage on the stability of normal spine and Lenke1 scoliotic spine. Firstly, according to X-ray computed tomography (CT) image data, four spinal finite element models (SFEMs), including normal spine without rib cage (N1), normal spine with normal rib cage (N2), scoliotic spine without rib cage (S1) and scoliotic spine with deformed rib cage (S2), from the first thoracic vertebrae to the sacral vertebrae (T1～S) were established. Secondly, the natural vibration characteristics of the four SFEMs were obtained by modal analysis. Finally, the maximum vibration amplitudes of the four SFEMs under external excitation were obtained by steady-state analysis. As shown in results, compared with N1, the maximum deformation of N2 segment T4～T6 in the -axis (coronal axis), -axis (sagittal axis) and -axis (vertical axis) directions decreases by 38.44%, 53.80% and 33.72%, respectively. Compared with S1, the maximum deformation of S2 segment T4～T6 in the -axis direction, -axis direction and -axis directions decreases by 44.26%, increases by 32.80% and decreases by 49.23%, respectively. As it can be seen, for normal spine, the rib cage can improve the stability of the whole spine in three directions; for the Lenke1 scoliotic spine, the rib cage can reduce the vibration of the scoliotic spine in the -axis and -axis directions and improves the stability of the whole spine in the two directions, while in the -axis direction, for the serious severe anteversion of scoliotic spine, the deformed rib cage exacerbates the vibration of the scoliotic spine in this direction and destroys the stability of the scoliotic spine in the -axis direction. This study reveals the biomechanical characteristics of rib caged influence on the stability of the scoliotic spine and it has guiding significance for the study of daily protection methods and protective tools for scoliotic patients.
Biomechanical Phenomena ; Finite Element Analysis ; Humans ; Rib Cage ; Scoliosis ; physiopathology ; Spine ; Thoracic Vertebrae ; Tomography, X-Ray Computed ; Vibration

Scoliosis is a complex spinal three-dimensional malformation with complicated pathogenesis, often associated with complications as thoracic deformity and shoulder imbalance. Because the acquisition of specimen or animal models are difficult, the biomechanical study of scoliosis is limited. In recent years, along with the development of the computer technology, software and image, the technology of establishing a finite element model of human spine is maturing and it has been providing strong support for the research of pathogenesis of scoliosis, the design and application of brace, and the selection of surgical methods. The finite element model method is gradually becoming an important tool in the biomechanical study of scoliosis. Establishing a high quality finite element model is the basis of analysis and future study. However, the finite element modeling process can be complex and modeling methods are greatly varied. Choosing the appropriate modeling method according to research objectives has become researchers' primary task. In this paper, the author reviews the national and international literature in recent years and concludes the finite element modeling methods in scoliosis, including data acquisition, establishment of the geometric model, the material properties, parameters setting, the validity of the finite element model validation and so on.
Biomechanical Phenomena ; Computer Simulation ; Finite Element Analysis ; Humans ; Scoliosis ; physiopathology ; surgery ; Spine ; pathology

The clinical effects of two different methods-high-viscosity cement percutaneous vertebroplasty (PVP) and low-viscosity cement percutaneous kyphoplasty (PKP) in the treatment of osteoporotic vertebral compression fractures (OVCFs) were investigated. From June 2010 to August 2013, 98 cases of OVCFs were included in our study. Forty-six patients underwent high-viscosity PVP and 52 patients underwent low-viscosity PKP. The occurrence of cement leakage was observed. Pain relief and functional activity were evaluated using the Visual Analog Scale (VAS) and Oswestry Disability Index (ODI), respectively. Restoration of the vertebral body height and angle of kyphosis were assessed by comparing preoperative and postoperative measurements of the anterior heights, middle heights and the kyphotic angle of the fractured vertebra. Nine out of the 54 vertebra bodies and 11 out of the 60 vertebra bodies were observed to have cement leakage in the high-viscosity PVP and low-viscosity PKP groups, respectively. The rate of cement leakage, correction of anterior vertebral height and kyphotic angles showed no significant differences between the two groups (P>0.05). Low-viscosity PKP had significant advantage in terms of the restoration of middle vertebral height as compared with the high-viscosity PVP (P<0.05). Both groups showed significant improvements in pain relief and functional capacity status after surgery (P<0.05). It was concluded that high-viscosity PVP and low-viscosity PKP have similar clinical effects in terms of the rate of cement leakage, restoration of the anterior vertebral body height, changes of kyphotic angles, functional activity, and pain relief. Low-viscosity PKP is better than high-viscosity PVP in restoring the height of the middle vertebra.
Administration, Cutaneous ; Aged ; Bone Cements ; chemistry ; therapeutic use ; Female ; Follow-Up Studies ; Fractures, Compression ; pathology ; rehabilitation ; surgery ; Humans ; Kyphoplasty ; instrumentation ; methods ; Male ; Middle Aged ; Osteoporosis ; pathology ; rehabilitation ; surgery ; Pain ; diagnosis ; physiopathology ; Pain Measurement ; Recovery of Function ; physiology ; Spinal Fractures ; pathology ; rehabilitation ; surgery ; Spine ; pathology ; surgery ; Treatment Outcome ; Viscosity ; Visual Analog Scale

PURPOSE: Anterior cervical discectomy and fusion (ACDF) has become a common spine procedure, however, there have been no previous studies on whole spine alignment changes after cervical fusion. Our purpose in this study was to determine whole spine sagittal alignment and pelvic alignment changes after ACDF. MATERIALS AND METHODS: Forty-eight patients who had undergone ACDF from January 2011 to December 2012 were enrolled in this study. Cervical lordosis, thoracic kyphosis, lumbar lordosis, sagittal vertical axis (SVA), and pelvic parameters were measured preoperatively and at 1, 3, 6, and 12 months postoperatively. Clinical outcomes were assessed using Visual Analog Scale (VAS) scores and Neck Disability Index (NDI) values. RESULTS: Forty-eight patients were grouped according to operative method (cage only, cage & plate), operative level (upper level: C3/4 & C4/5; lower level: C5/6 & C6/7), and cervical lordosis (high lordosis, low lordosis). All patients experienced significant improvements in VAS scores and NDI values after surgery. Among the radiologic parameters, pelvic tilt increased and sacral slope decreased at 12 months postoperatively. Only the high cervical lordosis group showed significantly-decreased cervical lordosis and a shortened SVA postoperatively. Correlation tests revealed that cervical lordosis was significantly correlated with SVA and that SVA was significantly correlated with pelvic tilt and sacral slope. CONCLUSION: ACDF affects whole spine sagittal alignment, especially in patients with high cervical lordosis. In these patients, alteration of cervical lordosis to a normal angle shortened the SVA and resulted in reciprocal changes in pelvic tilt and sacral slope.
Adult ; Aged ; Cervical Vertebrae/physiopathology/radiography/*surgery ; Cross-Sectional Studies ; *Diskectomy ; Female ; Humans ; Lordosis/etiology/*surgery ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Neck/surgery ; Retrospective Studies ; Spinal Diseases/complications/physiopathology/radiography/*surgery ; Spinal Fusion/*methods ; Spine ; Treatment Outcome ; Young Adult

OBJECTIVETo establish rabbit model of scoliosis induced with stable asymmetric lumbar loads.

METHODSScoliosis was induced in 10 two-month-old New Zealand rabbits using 316L stainless steel springs placed between the unilateral transverse processes of L2 and L5. Serial radiographs were documented before and at 1, 4, 8, 9 and 12 weeks after the operation. At weeks, the rabbits were randomly divided into SR group (n=5) with the spring removed and SK group (n=5) without spring removal.

RESULTSAll the rabbits survived the experiment with Cobb angle all greater than 10 degree at the end of the experiment. Significant changes were found in the Cobb angles and kyphotic angles at 1, 4 and 8 weeks after the operation (P<0.05). At 8 weeks, the Cobb angle, the kyphotic angle and the length of the spring were similar between SR and SK groups (P>0.05), and in the 4 weeks following spring removal in SR group, the Cobb angle and the kyphosis decreased significantly compared with those in SK group (P<0.05). Micro-CT showed that the BV/TV of the concave side was greater than that of the convex side. The length of the spring did not show obvious changes during the experiment (P>0.05).

CONCLUSIONSAsymmetric lumbar loading is a convenient, time-saving, and highly reproducible approach for establishing rabbit models of scoliosis.

Animals ; Disease Models, Animal ; Rabbits ; Scoliosis ; physiopathology ; Spine ; pathology

BACKGROUNDThe cause of the adjacent segment degeneration (ASD) after fusion remains unknown. It is reported that adjacent facet joint stresses increase after anterior cervical discectomy and fusion. This increase of stress rate may lead to tissue injury. Thus far, the load rate of the adjacent segment facet joint after fusion remains unclear.

METHODSSix C2-C7 cadaveric spine specimens were loaded under four motion modes: Flexion, extension, rotation, and lateral bending, with a pure moment using a 6° robot arm combined with an optical motion analysis system. The Tecscan pressure test system was used for testing facet joint pressure.

RESULTSThe contact mode of the facet joints and distributions of the force center during different motions were recorded. The adjacent segment facet joint forces increased faster after fusion, compared with intact conditions. While the magnitude of pressures increased, there was no difference in distribution modes before and after fusion. No pressures were detected during flexion. The average growth velocity during extension was the fastest and was significantly faster than lateral bending.

CONCLUSIONSOne of the reasons for cartilage injury was the increasing stress rate of loading. This implies that ASD after fusion may be related to habitual movement before and after fusion. More and faster extension is disadvantageous for the facet joints and should be reduced as much as possible.

Biomechanical Phenomena ; Humans ; In Vitro Techniques ; Lumbar Vertebrae ; physiopathology ; Range of Motion, Articular ; physiology ; Spinal Fusion ; adverse effects ; Spine ; physiopathology

OBJECTIVETo evaluate the role that post-operative difference value of pelvic incidence and lumbar lordosis (PI-LL) played on loss of correction, implant failure and health-related quality of life during follow-up in degenerative scoliosis patients.

METHODSRetrospective review of 62 patients (average age (57 ± 10) years, 11 male and 51 female patients) with degenerative scoliosis who underwent one stage posterior surgical instrumentation in the affiliated Drum Tower Hospital of Nanjing University Medical School from January 2005 to December 2011. The mean follow-up duration was 4.2 years. Long-cassette standing upright sagittal radiographs were obtained before and after operation and at the last follow-up. At the last follow-up, visual analogue scale and Oswestry disability index were collected. Based on post-operative PI-LL, patients were divided into two groups: group A (-9° < post-operative PI-LL<9°) and group B (post-operative PI-LL < -9°or post-operative PI-LL>9°). Independent t test and χ(2) test were performed for statistical analysis. For all statistical analysis, the level of significance was set at P < 0.05.

RESULTSNo difference was observed in terms of loss of correction between two groups during follow-up. More implant failure were observed in group B (15.63% vs. 6.7%, χ(2) = 21.85, P = 0.012). In addition, patients with better PI-LL matching came with better visual analogue scale (3.9 ± 2.4 vs. 5.2 ± 3.3, F = 0.089, P = 0.024).

CONCLUSIONWorse quality of life and increased risk for implant failure during follow-up may be related to mismatched PI-LL.

Aged ; Female ; Humans ; Incidence ; Lordosis ; complications ; physiopathology ; Male ; Middle Aged ; Pain Measurement ; Pelvis ; Postoperative Period ; Posture ; Quality of Life ; Retrospective Studies ; Scoliosis ; complications ; physiopathology ; Spine ; Treatment Outcome

OBJECTIVETo explore the clinical outcomes of percutaneous vertebroplasty (PVP) and percutaneous kyphoplasty (PKP) in treating osteoporotic vertebral compression fracture (OVCF).

METHODSFrom January 2007 to February 2010, the data of 40 patients with osteoporotic vertebral compression fracture underwent treatment were retrospectively analyzed. Of them,20 patients were treated with PVP (PVP group), there were 8 males and 12 females with an average age of (66.37 +/- 2.34) years old (54 to 81); 20 patients were treated with PKP (PKP group), there were 11 males and 9 females with an average of (65.12 +/- 3.21) years old (56 to 79). Postoperative at 1 week, 12 weeks, 1 year, pain and daily life function were respectively assessed by visual analogue scale (VAS) and Barthel index (BI); and anterior height of responsibility vertebra, Cobb angle were measured by X-rays.

RESULTSIn PVP group, 1 case complicated with bone cement leakage without clinical symptoms and no operation to treat. No postoperative infection and deep vein thrombosis were found between two groups. All patients were followed up more than 1 year, pain and daily life function has obviously improved than preoperative (P < 0.01); and there was no significant difference on 1 week, 12 weeks, 1 year after operation (P > 0.05); there was no significant difference between two groups (P > 0.05). In PVP group, there was no significant difference in anterior height of responsibility vertebra, Cobb angle before and after operation;and in PKP group, postoperative data has obviously improved than preoperative (P < 0.01), but there was no significant difference postoperative at 1 week, 12 weeks, 1 year (P > 0.05); there was no significant difference between two groups at 1 week, 12 weeks, 1 year after operation.

CONCLUSIONBoth the methods can obviously relieve pain and completely or partly recover daily life function in treating OVCF. But PKP has advantages of recovery of anterior height of responsibility vertebra and correction of Cobb angle, especially for serious compression.

Aged ; Aged, 80 and over ; Female ; Fractures, Compression ; diagnostic imaging ; physiopathology ; surgery ; Humans ; Kyphoplasty ; Male ; Middle Aged ; Osteoporotic Fractures ; diagnostic imaging ; physiopathology ; surgery ; Radiography ; Recovery of Function ; Retrospective Studies ; Spinal Fractures ; diagnostic imaging ; physiopathology ; surgery ; Spine ; surgery ; Treatment Outcome

OBJECTIVETo investigate whether pinching spine (PS, i.e. , a traditional Chinese manipulative therapy) is beneficial to ameliorating the depressive state (including behavioral deficit, retardative weight gain and decreased sucrose consumption) in a rat model of depression induced by chronic unpredictable stress (CUS) and to explore the candidate mechanism of action.

METHODSPS was performed on rats' spine once daily for 1 week after exposure to CUS. The open-field test, body weight measuring, and sucrose intake test were applied on different dates: before stress (d0), at the end of stress (d21) and after PS treatment (d28), respectively. Then the rats' hippocampuses were performed genome-wide microarray analysis, and the expression levels of several genes were evaluated by real-time polymerase chain reaction (PCR).

RESULTSExposure to CUS resulted in decreases of behavioral activity and sucrose consumption, which were reversed significantly after PS treatment. The expression of several genes relevant to energy metabolism, anti-oxidation, and olfactory receptor, etc., were down-regulated, while the expression of those relevant to hemostasis, immunity-inflammation, and restriction of activities and ingestion, etc., were up-regulated in hippocampuses of rats exposed to CUS. PS treatment significantly inverted these changes. Furthermore, increase or decrease in gene expression evaluated by realtime PCR was concordant with up-regulated or down-regulated expression evaluated by microarray analysis.

CONCLUSIONPS showed a potential antidepressant-like effect, of which the action mechanism might be due to gene expression regulation in hippocampus.

Animals ; Depression ; therapy ; Male ; Medicine, Chinese Traditional ; Musculoskeletal Manipulations ; Rats ; Rats, Sprague-Dawley ; Spine ; physiopathology

OBJECTIVETo investigate if the growth patterns of the spine and pelvis are consistent in adolescent idiopathic scoliosis (AIS) patients with single thoracic curves.

METHODSForty-eight thoracic adolescent idiopathic scoliosis (T-AIS) female patients and 48 healthy age-matched adolescents were recruited consecutively between December 2011 and October 2012. Radiographic parameters including height of spine (HOS), length of spine (LOS), height of thoracic spine (HOT), length of thoracic spine (LOT), height of pelvis (HOP), width of pelvis (WOP) and width of thorax (WOT) were measured on the long-cassette posteroanterior standing radiographs. In addition, ratios including HOS/HOP, LOS/HOP, HOT/HOP, LOT/HOP, LOS/LOT, WOT/WOP were also calculated. Independent t-test was performed to compare the radiographic parameters and ratios between the two groups.

RESULTSCompared to the age-matched healthy adolescents, T-AIS patients had a significantly higher LOS and LOT (t = -2.364 and -1.495, P = 0.020 and 0.043) and smaller HOS and HOT (t = 2.060 and 3.359, P = 0.042 and 0.001). Yet, all of HOP, WOP and WOT showed no significant difference between T-AIS patients and healthy adolescents. Similarly, LOS/HOP and LOT/HOP were significantly higher in T-AIS patients as may be expected with an average LOS/HOP of 2.26 ± 0.14 in normal controls.In addition, LOS/LOT in normal controls had a trend of increase with age which was different from the stable LOS/LOT in T-AIS patients, indicating an increased growth of thoracic vertebra compared to lumbar vertebra.

CONCLUSIONSCompared to the age-matched healthy adolescents, T-AIS patients have an abnormal growth characteristics with longer spine. The growth of pelvis and thorax show no significant differences between T-AIS patients and healthy adolescents.

Adolescent ; Case-Control Studies ; Child ; Female ; Humans ; Pelvis ; diagnostic imaging ; growth & development ; Radiography ; Scoliosis ; physiopathology ; Spine ; diagnostic imaging ; growth & development ; Thoracic Vertebrae ; diagnostic imaging ; growth & development