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1.
Energy Build ; 226: 110371, 2020 Nov 01.
Article in English | MEDLINE | ID: mdl-32836721

ABSTRACT

After the Green Building Regulations in the Zhejiang Province was put into effect in May 2016, cities and prefectures in the province were given directives to set their own individual targets for the provision of green buildings. The city of Ningbo decided to use this opportunity to develop a systematic procedure, using Fuzzy Analytical Hierarchy Process (FAHP), to identify which allotments within the municipal area have the greatest potential of delivering green buildings, ensuring the set targets are fair and deliverable. This paper explains in detail the use of FAHP in the production of the Specific Plans for Green Buildings for the city of Ningbo in the Zhejiang Province of China. This innovative multi-faceted method incorporates the level of development in each of the 3213 land allotments in the municipal area, assessing each one for critical aspects such as environmental potential, local economic development land-use and land prices in order to determine an individual roadmap for the ratio of green buildings to be built in each region within the city. This method incorporates a scientific process, in which Pairwise Comparison Analysis was conducted for the selected criteria and aspects to determine the weighting factors and scores in each case. This allowed planners to rank all allotments in the municipal area in terms of their potential to provide green buildings, and thus make the setting of targets to provide these accordingly. This approach breaks away from the traditional method which relies on simple estimation, which is often unjustified. Over the two years since this method was introduced, the effects had been positive, within all the allotments abiding to the set targets. Other cities and regions in China, such as the provinces of Liaoning and Hebei, have also adopted this process. The Specific Plans for Green Buildings in Ningbo also include the adoption rate of prefabricated buildings and the mandatory date for when by which new residential buildings should be fully-furnished before they are sold (this is not currently the case in most residential buildings in China). These aspects are also discussed in this paper.

2.
Work ; 61(3): 403-411, 2018.
Article in English | MEDLINE | ID: mdl-30373993

ABSTRACT

BACKGROUND: Low back pain (LBP) is a common health problem with high reoccurrence rate. As patients with LBP are often found to be proprioception impaired, new proprioception exercises should be explored. Whole body vibration (WBV) has been proven to improve muscle function and proprioception. OBJECTIVE: The aim of this study was to determine the effects of WBV on spinal proprioception when WBV was administered in standing and seated postures. METHODS: Twenty healthy male individuals (mean age: 23.2±1.2 years) were recruited and randomly assigned to two WBV groups: WBV in standing or WBV in seated posture. Their body posture, lumbar repositioning ability, maximum reaching distance and lumbopelvic coordination during dynamic motion in flexion and extension were assessed before, immediately after, 30 minutes after and 1 hour after 5 minutes of WBV (18 Hz, 6 mm amplitude) exposure. A Mixed ANOVA was used to analyze the effects of group and time factors on these four outcome measures. RESULTS: There were no significant interaction (group and time) and group effects on all outcome measures. Participants were found to have significant different time effect on body posture, lumbar repositioning ability, maximum reaching distance and lumbopelvic coordination. CONCLUSIONS: WBV could significantly improve spinal proprioception including body posture, lumbar repositioning ability, maximum reaching distance and lumbopelvic coordination in healthy individuals. WBV protocol is recommended to confirm its clinical application for improving spinal proprioception and its effects on patients with LBP is warranted.


Subject(s)
Occupational Injuries/etiology , Proprioception/physiology , Spinal Cord/physiology , Vibration/adverse effects , Adult , Analysis of Variance , Female , Humans , Male , Middle Aged , Occupational Injuries/physiopathology , Posture/physiology
3.
Appl Ergon ; 55: 133-137, 2016 Jul.
Article in English | MEDLINE | ID: mdl-26995043

ABSTRACT

Manual load carriage continues to be a major contributor of musculoskeletal injury. This study investigates the physiological and subjective effects of an on-hip load-carrying belt (HLCB) during bimanual anterior load carriage. Fifteen healthy male participants walked on a level ground treadmill at 4.5 km/h for 5 min carrying 5, 10 and 15 kg loads with hands and arms in front of the body, with and without using the HLCB (WD and ND). Heart rate, normalized oxygen uptake, minute ventilation and, central and peripheral ratings of perceived exertion were the dependent variables. The mean heart rate, normalized oxygen uptake, minute ventilation and peripheral rating of perceived exertion increased significantly with load under both WD and ND conditions. At a load of 15 kg, the mean heart rate, normalized oxygen uptake, minute ventilation and peripheral rating of perceived exertion were significantly lower by 6.6%, 8.0%, 11.8% and 13.9% respectively in WD condition when compared to the ND condition. There was no significant difference between WD and ND conditions with 5 or 10 kg load. It can be concluded that the HLCB could reduce a person's physiological and peripheral perceptual responses when walking on a level ground treadmill at 4.5 km/h with a load of 15 kg. Using a HLCB or similar device is therefore recommended for bimanual anterior load carriage for loads of 15 kg or probably larger.


Subject(s)
Physical Exertion , Protective Clothing , Task Performance and Analysis , Walking , Weight-Bearing/physiology , Adolescent , Adult , Biomechanical Phenomena , Exercise Test/methods , Healthy Volunteers , Heart Rate/physiology , Hip/physiology , Humans , Male , Oxygen Consumption , Perception , Young Adult
4.
Article in English | MEDLINE | ID: mdl-24110855

ABSTRACT

Low back pain (LBP) is a common health problem with high reoccurrence rate. While most LBP cases are classified as non-specific, patients in general often present impaired proprioception. Whole body vibration (WBV) has been proven to improve muscle function and proprioception in the lumbo-pelvic region. The aim of this study was to determine whether WBV would affect spinal proprioception. Eleven young normal individuals were recruited. Their body alignment, lumbar repositioning error and lumbo-pelvic coordination during dynamic motion were assessed before and after 5 minutes WBV (18 Hz, 6 mm amplitude). Assessments were conducted before, immediately after, 30 minutes after and 1 hour after WBV. Subjects were found to have improved lumbo-pelvic coordination and flexibility without any adverse effect on the neuromuscular system after WBV. However, WBV had no significant immediate effect on lumbar repositioning ability and body alignment. Future studies of the effects of different WBV protocols on LBP patients are recommended.


Subject(s)
Low Back Pain/rehabilitation , Physical Therapy Modalities , Proprioception/physiology , Vibration , Adult , Humans , Male , Motion , Pelvis , Posture , Reproducibility of Results , Young Adult
5.
Ergonomics ; 53(1): 56-64, 2010 Jan.
Article in English | MEDLINE | ID: mdl-20069481

ABSTRACT

Backpack weight of 10-15% has been recommended as an acceptable limit for schoolchildren. However, there is still no clear guideline regarding where the backpack centre of gravity (CG) should be positioned. The changes of spinal curvature and repositioning error when carrying a backpack loaded at 15% of body weight at different CG locations (anterior or posterior at T7, T12 or L3) in schoolchildren were analysed. Both spinal curvature and repositioning error were found to be affected by backpack anterior-posterior position and CG level. A relatively smaller change was observed during anterior carriage with the least change when the backpack CG was positioned at T12. The results also suggested that alternative carriage by changing the backpack position occasionally between anterior and posterior positions might help to relieve the effects of backpack on spine. However, future study is recommended to further substantiate the beneficial effects of alternative carriage on children. STATEMENT OF RELEVANCE: Anteriorly carried backpack with centre of gravity positioned at T12 was shown to induce relatively less effect on spinal deformation and repositioning error in schoolchildren. Changing backpack carriage position occasionally may help to relieve its effects on spinal deformation. The findings are important for ergonomic schoolbag design and determining a proper load carriage method.


Subject(s)
Lifting/adverse effects , Postural Balance/physiology , Spinal Curvatures/etiology , Students , Biomechanical Phenomena , Child , Female , Humans , Male , Posture/physiology , Task Performance and Analysis
6.
Ergonomics ; 51(9): 1376-93, 2008 Sep.
Article in English | MEDLINE | ID: mdl-18802820

ABSTRACT

This study aims to evaluate the wear comfort of eight commercially available maternity support garments. The thermophysiological, sensory/tactile and movement comfort were assessed in a wear trial using a 19-item questionnaire. Fourteen pregnant Chinese women aged 32.3 +/- 4.2 years were recruited from a local obstetric clinic. The results show that the tested garments generally provided greater sensory comfort than thermophysiological comfort. The thermophysiological comfort was mainly influenced by the fibre contents and breathability. Significant linear relationships were found between material appearance and hand feel (r = 0.86, p < 0.001), and between non-itchiness and no red mark (r = 0.78, p < 0.001). Movement comfort was influenced by the garment type and style features. Overall, the soft, good-fit, cotton/elastane maternity brief was perceived as the best product. The findings of comfort needs in pregnant women and the effects of various garment attributes would be helpful for the development of maternity support garment design criteria that are required to satisfy critical ergonomic needs. Low back pain during pregnancy is a common and significant health problem. A maternity support garment is regarded as a convenient and safe device to stabilise the lumbar spine so as to relieve pain. However, patient compliance is likely to be affected by discomfort and inconvenience. The results of this study provide guidance for the optimal design of maternity support clothing.


Subject(s)
Clothing , Consumer Behavior , Adult , Asian People/ethnology , Female , Hong Kong , Humans , Pregnancy , Surveys and Questionnaires , Young Adult
7.
Proc Inst Mech Eng H ; 222(2): 241-8, 2008 Feb.
Article in English | MEDLINE | ID: mdl-18441759

ABSTRACT

Electroacupuncture (EA) has long been used as conservative treatment for low back pain (LBP). Its effect on relief of back pain has been demonstrated in many clinical studies. However, whether it has any effect on the biological properties of an intervertebral disc, which is one of the major causes of LBP, is still unclear. The aim of this study was, therefore, to investigate the effects of EA with different simulation frequencies on an intervertebral disc with simulated degeneration using an in-vivo rat-tail model. In this study, 33 rats were used. Disc degeneration was simulated in the rat caudal 8-9 disc via continuous static compressive loading of 11 N for 2 weeks. EA with a frequency of 2 or 100 Hz was then applied to the degenerated disc for 3 weeks with 3 sessions/week and 20 min/session. The intervertebral disc height was measured before and after compression as well as after EA intervention for 3 weeks. The static compression was found to result in a reduction in the disc height of about 22 per cent. There was no evidence that this change could be reversed after resting or the EA intervention. However, EA at 100 Hz was found to induce a further decrease in disc height, which was not shown for the rats after resting or EA at 2 Hz. The results of this study showed that effects of EA on disc degeneration are frequency dependent and adverse effects could result if EA at a certain frequency was used.


Subject(s)
Disease Models, Animal , Electroacupuncture/methods , Intervertebral Disc Displacement/physiopathology , Intervertebral Disc Displacement/therapy , Joint Instability/physiopathology , Animals , Humans , Intervertebral Disc Displacement/diagnosis , Joint Instability/diagnosis , Male , Rats , Rats, Sprague-Dawley , Tail/physiopathology , Treatment Outcome
8.
Ergonomics ; 50(12): 2148-56, 2007 Dec.
Article in English | MEDLINE | ID: mdl-17891594

ABSTRACT

Despite evidence linking backpack carriage and back pain, previous studies to examine the effects of backpack carriage have focused on changes in physical performance rather than the direct effects on the spine itself. Spinal curvature and proprioception (in terms of spinal repositioning consistency) of 15 schoolboys during normal upright stance without a backpack and while carrying a specially adapted backpack loaded at 10, 15 and 20% of their bodyweight were measured and compared using repeated measures ANOVA. A significant flattening of the lumbar lordosis and the upper thoracic kyphosis was found with increasing backpack load, as well as a significant decrease in the thoraco-lumbar and lumbar repositioning consistencies. Carriage of a loaded backpack causes immediate changes in spinal curvature and appears to have a direct effect on the repositioning consistency. Further investigation of the changes in spinal curvature and repositioning consistency over time with prolonged backpack carriage is warranted. Daily carriage of a school backpack on the musculoskeletal health of children and adolescents has become an area of concern due to the association between backpack carriage and back pain. Data regarding the direct effect of backpack carriage on the spine in children are limited.


Subject(s)
Spinal Curvatures/etiology , Weight-Bearing/physiology , Adolescent , Biomechanical Phenomena , Hong Kong , Humans , Male , Postural Balance , Walking
9.
Ergonomics ; 49(9): 860-73, 2006 Jul 15.
Article in English | MEDLINE | ID: mdl-16801232

ABSTRACT

Poor posture has been suggested as one of the main factors contributing to the high prevalence of neck pain in video display unit (VDU) users, but no clear association between pain and any particular resting neck posture has been found. Postural awareness of the neck, as indicated by the repositioning accuracy, may therefore be an appropriate measure and potentially useful assessment tool. The objective of this study is to examine whether posture and fatigue affect the head repositioning ability in typical VDU usage. A group of 20 healthy participants reproduced a normal comfortable posture for forward, upright and backward chair back inclinations in random order both before and after fatigue of the upper trapezius muscles. Ten repetitions of the posture were recorded for 2 s each, and the angular and translational deviations from the original head position were measured with regard to the external environment (head in space repositioning) and with regard to the trunk (head on trunk repositioning). Analysis by repeated measures ANOVA showed significant effects and interactions of fatigue and chair back inclination on the repositioning errors in the sagittal plane, which typically showed systematic trends towards certain postures rather than random errors around a mean position. While further work is required to examine the ergonomic impact of impaired repositioning ability, head repositioning is sensitive to ergonomic factors such as seating configuration and fatigue, and may therefore be a useful tool for evaluation of static working postures.


Subject(s)
Fatigue , Head , Posture , Adult , Computer Terminals , Ergonomics , Female , Humans , Male , Postural Balance
10.
Aliment Pharmacol Ther ; 21(7): 841-9, 2005 Apr 01.
Article in English | MEDLINE | ID: mdl-15801919

ABSTRACT

BACKGROUND: Long-term effect of YMDD mutations on liver histology in Chinese hepatitis B patients is unknown. AIM: To examine the effect of prolonged lamivudine treatment on liver histology in Chinese patients with and without YMDD mutations. METHODS: Liver histology was assessed in 85 patients on long-term lamivudine at baseline and year 1, and at year 3 for 25 patients. RESULTS: Comparing patients with and without YMDD mutations at year 1, the former had higher baseline median necroinflammatory (11 vs. six respectively, P = 0.014) and fibrosis scores (three vs. one respectively, P = 0.001). The proportion of patients with improvement in necroinflammation and worsening of fibrosis was comparable for patients with and without YMDD mutations at year 1 (57.1%, 14.3% vs. 55%, 15% respectively) and year 3 (57.9%, 26.3% vs. 50%, 16.7% respectively). Comparing the histology at year 1 and 3, more patients with YMDD mutations developing after year 1 had worsening of necroinflammation than patients with persistent YMDD wild type (53.8% vs. 25% respectively). CONCLUSIONS: Patients who developed YMDD mutations had higher baseline histological scores. With YMDD mutations, the liver histology became less favourable after 3 years than at the first year, although there was still improvement when compared with that at baseline.


Subject(s)
Asian People/genetics , Hepatitis B, Chronic/drug therapy , Lamivudine/therapeutic use , Liver/pathology , Reverse Transcriptase Inhibitors/therapeutic use , Adolescent , Adult , Biopsy/methods , China/ethnology , DNA, Viral/genetics , Female , Hepatitis B virus/genetics , Hepatitis B, Chronic/ethnology , Hepatitis B, Chronic/pathology , Humans , Liver Cirrhosis/pathology , Liver Cirrhosis/virology , Male , Middle Aged , Mutation/genetics
11.
Biomed Mater Eng ; 14(3): 271-9, 2004.
Article in English | MEDLINE | ID: mdl-15299239

ABSTRACT

An active finite element model was developed to predict the mechanical behaviors of skeletal muscle-tendon complex during isometric, shortening and lengthening contraction. The active finite element was created through incorporation of a user-defined material property into ABAQUS finite element code. The active finite element is controlled by a motor element that is activated by a mathematical function. The nonlinear passive behavior of the muscle was defined by the viscoelastic elements and can be easily altered to other properties by using other elements in the material library without the need of re-defining the constitutive relation of the muscle. The isometric force-length relationship, force-strain relations of the muscle-tendon complex during both shortening and lengthening contraction and muscle relaxation response were predicted using the proposed finite element model. The predicted results were found to be in good agreement with available experimental data. In addition, the stress distribution in the muscle-tendon complex during isometric, shortening and lengthening contractions was simulated. The location of the maximum stress may provide useful information for studying muscle damage and fatigue in the future.


Subject(s)
Algorithms , Models, Biological , Movement/physiology , Muscle Contraction/physiology , Muscle, Skeletal/physiology , Tendons/physiology , Animals , Ankle/physiology , Computer Simulation , Finite Element Analysis , Isometric Contraction/physiology , Rats , User-Computer Interface
12.
J Rehabil Res Dev ; 38(1): 1-6, 2001.
Article in English | MEDLINE | ID: mdl-11322461

ABSTRACT

Despite the fact that non-level walking is known to be important for prosthesis fitting, its clinical significance has not been investigated. In this study, the acceptable prosthesis alignment ranges of six subjects with transtibial amputation on level and non-level walking were determined and compared. With the aid of a recently developed alignment jig, prosthesis fitting was performed for each subject with varied anterior-posterior (AP) alignments. Conventional assessments and the subjects' comment were used to determine whether the alignment was acceptable or not. The results showed that the acceptable alignment range for non-level walking consistently fell within and was significantly smaller than that for level walking with p<0.05. It was evident that non-level walking is important for better approximation of optimum alignment and should be included in routine prosthesis fitting.


Subject(s)
Artificial Limbs , Prosthesis Fitting , Walking/physiology , Adult , Amputation, Surgical , Female , Humans , Leg , Male , Middle Aged , Tibia/surgery
13.
J Bone Miner Res ; 16(12): 2348-55, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11760851

ABSTRACT

A large osteopenic animal model that resembles human osteoporotic changes is essential for osteoporosis research. This study aimed at establishing a large osteopenic animal model in goats. Twenty-five Chinese mountain goats were used in which they were either ovariectomized (OVX) and fed with a low-calcium diet (n = 16) or sham-operated (SHAM; n = 9). Monthly photodensitometric analysis on proximal tibial metaphysis and calcaneus was performed. Two iliac crest biopsy specimens obtained before and 6 months after OVX were used for bone mineral density (BMD) measurement with peripheral quantitative computed tomography (pQCT). Lumbar vertebrae (L2 and L7), humeral heads, and calcanei were collected for BMD measurement after euthanasia. The humeral heads and calcanei were used in biomechanical indentation test. BMD measurement showed a significant 25.0% (p = 0.006) decrease in BMD of the iliac crest biopsy specimens 6 months after OVX. It also was statistically significant when compared with the SHAM (p = 0.028). BMD at L2, L7, calcaneus, and humeral head reduced by 24-33% (p ranged from 0.001 to 0.011) when compared with the SHAM. Photodensitometry showed a continuous decrease in bone density after OVX. There were significant decreases of 18.9% in proximal tibial metaphysis (p = 0.003) and 21.8% in calcaneus (p = 0.023) in the OVX group 6 months postoperatively. Indentation test on the humeral head and calcaneus showed a significant decrease 52% (p = 0.006) and 54% (p = 0.001), respectively, in energy required for displacement of 3 mm in the OVX group compared with the SHAM group. The decreases correlated significantly to the decrease in BMD of the corresponding specimens (r2 = 0.439 and 0.581; p < 0.001 for both). In conclusion, this study showed that OVX plus a low-calcium diet could induce significant osteopenia and deterioration of mechanical properties of the cancellous bone in goats.


Subject(s)
Bone Diseases, Metabolic/physiopathology , Disease Models, Animal , Animals , Bone Density , Female , Goats , Ovariectomy
14.
J Rehabil Res Dev ; 37(3): 255-60, 2000.
Article in English | MEDLINE | ID: mdl-10917257

ABSTRACT

Residual limb recovery after a transtibial amputation depends largely on close monitoring of the weight-bearing activities during the early postoperative stage. Although a biofeedback device, in particular audio biofeedback, was recommended to be used, no quantitative studies regarding its effectiveness in monitoring the weight-bearing activity of a person with amputation were available. In this study, six persons with transtibial amputation were asked to replicate a prescribed amount of weight bearing using a bathroom scale method during their early postoperative ambulatory training. Their weight-bearing characteristics with and without using audio biofeedback were continuously monitored using a load monitoring device and compared with the prescribed load. The results showed that the residual limb would be overloaded using the conventional bathroom scale method during early postoperative ambulatory training if no audio biofeedback was provided. It was demonstrated that audio biofeedback was useful in preventing the residual limb from being overloaded beyond the prescribed load particularly when the prescribed load was low.


Subject(s)
Amputation, Surgical/rehabilitation , Biofeedback, Psychology/instrumentation , Walking/physiology , Aged , Amputation, Surgical/methods , Analysis of Variance , Artificial Limbs , Female , Humans , Leg , Male , Postoperative Period , Reference Values , Weight-Bearing
15.
Appl Opt ; 38(9): 1502-5, 1999 Mar 20.
Article in English | MEDLINE | ID: mdl-18305773

ABSTRACT

The first (to our knowledge) III-V mid-IR vertical-cavity surface-emitting lasers (lambda = 2.9 microm) are demonstrated and show promising characteristics for chemical detection applications. The cw optical-pumping threshold is low (4 mW at 80 K) and efficiency is high (5.6% W/W). Pulsed operation is obtained up to 280 K and cw up to 160 K. Lateral-mode confinement will lead to spectrally pure, single-mode output for chemical identification.

16.
Prosthet Orthot Int ; 23(3): 225-30, 1999 Dec.
Article in English | MEDLINE | ID: mdl-10890597

ABSTRACT

Clinically, it is hard to achieve and reproduce prosthesis alignment at will during daily prosthesis fitting. A new alignment jig was designed and developed to facilitate quantification and prescription of prosthesis alignment for patellar-tendon-bearing (PTB) trans-tibial prostheses. The alignment jig provided instantaneous readings of the three-dimensional orientation and position of the socket relative to the prosthetic foot in standardised units. The inter- and intra-tester errors of the alignment jig in measuring prosthesis alignment were evaluated and demonstrated to have good reliability. The alignment jig was recommended to be used clinically after the conventional dynamic alignment procedure to document the prosthesis alignment. Further application of the alignment jig for systematic evaluation of the effects of prosthesis alignment on gait for trans-tibial amputees is suggested.


Subject(s)
Artificial Limbs , Prosthesis Design/instrumentation , Humans , Leg
17.
Clin Orthop Relat Res ; (337): 13-26, 1997 Apr.
Article in English | MEDLINE | ID: mdl-9137172

ABSTRACT

Fusion of the spine while restoring stability of the spinal segment, fails to preserve spinal mobility. Long term complications of accelerated degeneration in the neighboring segments have been reported. The present study explores the possibility of intervertebral disc autografting in a bipedal animal model by isolating a lumbar disc together with the adjacent end plates and repositioning it with minimal internal fixation. Fourteen Rhesus monkeys were sacrificed at 2, 4, 6, and 12 months after surgery and the grafted discs were examined radiologically, biochemically, pathologically, and biomechanically. Healing of the bony end plate was seen between 2 to 4 months postoperatively. There was early loss of disc height at 2 and 4 months but there was a suggestion of some reconstitution up to 12 months. There was minimal evidence of gross degeneration at all stages. Gradual loss of water content was found in the annulus and the nucleus. The nucleus pulposus seemed to be able to reaccumulate proteoglycan after an initial drop in the first 4 months. There was significant increase in hydroxyproline content in the annulus fibrosus and the nucleus pulposus. Biomechanically, the grafted disc showed hypermobility in the first 4 months but gradually became stabilized with time. Results from this study suggested that a fresh intervertebral disc autograft could survive a period of ischemia. Although the physiology of the disc was deranged, it was able to preserve a certain degree of segmental mobility without sacrificing stability. Further studies are required to validate these results and the field of disc allografting should be explored.


Subject(s)
Intervertebral Disc/transplantation , Transplantation, Autologous/methods , Animals , Biomechanical Phenomena , Body Water/metabolism , Hydroxyproline/analysis , Intervertebral Disc/chemistry , Lumbar Vertebrae/diagnostic imaging , Macaca mulatta , Proteoglycans/analysis , Radiography , Spine/physiology
18.
Spine (Phila Pa 1976) ; 21(5): 549-55, 1996 Mar 01.
Article in English | MEDLINE | ID: mdl-8852308

ABSTRACT

STUDY DESIGN: Segmental mobility and intradiscal pressure were measured and the data compared in six cadaveric lumbar spine specimens before and after in vitro simulated single level L4-5 and double level L4-5-S1 anterior interbody fusions. OBJECTIVE: The experimental objective was to study the biomechanical effects of single level L4-5 and double level L4-5-S1 anterior interbody fusions on the neighboring unfused segments. SUMMARY OF BACKGROUND DATA: The relationship between the local rigidity created by fusion mass and accelerated degeneration reported at the neighboring unfused intervertebral discs is not clear. METHODS: Six cadaveric lumbar spine specimens were biomechanically tested in flexion and extension. Segmental mobility and intradiscal pressure of the specimens were measured before and after in vitro simulation of single level L4-5 and double level L4-5-S1 anterior interbody fusions. RESULTS: The mobility of the motion segments immediately above and below an L4-5 fusion was increased in flexion. When the L5-S1 segment was also fused, the loss of segmental motion in both flexion and extension at the L4-5 and L5-S1 were compensated for by increased motion in all levels above the fusion. In both flexion and extension, the intradiscal pressures of all unfused intervertebral discs were increased after a single level L4-5 fusion and this increase was even more marked after a double level L4-5-S1 fusion. CONCLUSIONS: There is no evidence that the neighboring unfused segments are loaded beyond their physiological limits due to the fusion. However, the neighboring unfused segments have to work more frequently toward the extremes of their functional ranges of motion after fusion and these effects will be more marked after a double level L4-5-S1 fusion.


Subject(s)
Lumbar Vertebrae/metabolism , Spinal Fusion/adverse effects , Aged , Aged, 80 and over , Biomechanical Phenomena , Cadaver , Female , Humans , Intervertebral Disc/physiology , Lumbosacral Region/physiopathology , Male , Middle Aged , Movement , Pressure , Stress, Mechanical
19.
Spine (Phila Pa 1976) ; 20(7): 813-8, 1995 Apr 01.
Article in English | MEDLINE | ID: mdl-7701396

ABSTRACT

STUDY DESIGN: Segmental deformations of the lumbar spine in asymptomatic volunteers measured radiologically were compared with those in patients who underwent anterior interbody fusion. OBJECTIVE: To determine the effects of anterior lumbar interbody fusion on the juxta-fused segments. SUMMARY OF BACKGROUND DATA: Stiffness of a spinal segment after fusion was thought to be the cause of the degeneration process at the juxta-fused segments. METHODS: Segmental deformations of the lumbar spine, from maximum extension to maximum flexion, in 30 asymptomatic volunteers and 52 pain-free patients who had single-level L4-L5 or double-level L4-S1 fusion were measured and compared. RESULTS: The total flexibility of the lumbar spine was decreased after a single-level fusion and further decreased after double-level fusions. The segmental deformations of the juxta-fused segments also were decreased after either a single- or double-level fusion. CONCLUSIONS: During normal flexion and extension of the lumbar spine, the juxta-fused segments were not deformed beyond their physiological limits after fusion. Thus, accelerated degeneration observed at a juxta-fused segment is unlikely to be attributable to hypermobility.


Subject(s)
Intervertebral Disc Displacement/surgery , Lumbar Vertebrae/physiopathology , Lumbar Vertebrae/surgery , Range of Motion, Articular/physiology , Spinal Fusion , Adult , Follow-Up Studies , Humans , Intervertebral Disc Displacement/physiopathology , Lumbar Vertebrae/diagnostic imaging , Radiography , Retrospective Studies , Time Factors
20.
Spine (Phila Pa 1976) ; 14(6): 611-5, 1989 Jun.
Article in English | MEDLINE | ID: mdl-2749377

ABSTRACT

Previous study has shown that the iliolumbar ligament is important in restraining flexion, extension, and lateral bending of L5 on S1, and its effect on axial rotation was not apparent at 6 N-m of loading. An apparatus was devised to further evaluate its role in relation to the torsional stability of the lumbosacral junction. Torque-rotation characteristics were studied with 24 cadaveric lumbosacral-pelvic specimens. The specimens were divided into three groups. In Group A, the "facet joints," lumbosacral disc and the iliolumbar ligament were all intact. In Group B, the "facet joints" were removed, and in Group C, both the "facets" and the iliolumbar ligament were removed. The results indicated that the ligament was important in maintaining torsional stability of the lumbosacral junction and contributed to 35.2% of the normalized elastic strain energy of the junction.


Subject(s)
Ligaments/physiology , Spine/physiology , Humans , Lumbosacral Region , Physiology/instrumentation , Rotation , Stress, Mechanical
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