Forearm bone mineral density measurement with different scanning positions: a study in right-handed Chinese using dual-energy X-ray absorptiometry

The purpose of our study was to determine whether different scanning positions influence forearm bone mineral density (BMD) measurements and to evaluate the association between forearm BMDs in different scanning positions and those of other skeleton sites. The study population consisted of 30 right-handed healthy Chinese volunteers. BMD was measured with GE Lunar Prodigy at the left forearm in both sitting and supine positions, and at lumbar spine and the right femur. All subjects received repeated measurements in the same day (repositioning), and the average of repeated BMD results was used for analysis. The BMD precision errors of the nondominant forearm in the sitting and supine positions varied from 1.13% to 2.46%. There were no statistically significant differences between BMD precision errors for each region of interest (ROI) between sitting and supine positions (all the p values were greater than 0.05). When comparing BMDs on the same side in the sitting position with those in the supine position, there were significant differences at both the 1/3 radius level and in the total radius (p<0.05). The BMD values at these ROIs obtained in the supine position were lower than those in the routine sitting position. The BMDs of the ultradistal radius in the both 2 different scanning positions were significantly associated with lumbar spine and femoral neck BMD, respectively. The total radius BMD in the different positions was associated with the BMD of the femoral neck. A change in body scanning position from sitting to supine will significantly influence forearm BMD results.     

Sagittal lumbar and pelvic alignment in the standing and sitting positions

BackgroundThe sitting position has become the most common posture in today’s workplace. In relation to this position, kinematic analysis of the lumbar spine is helpful in understanding the causes of low back pain and its prevention.MethodsIn this study, we investigated the relationship between sagittal lumbar alignment and pelvic alignment in the standing and sitting positions for 50 healthy adults. Lumbar lordotic angle (LLA), sacral slope (SS), pelvic tilt (PT), and pelvic incidence (PI) were measured on lateral lumbar spine standing and sitting radiographs.ResultsRegarding changes from the standing to sitting positions, averageLLA, SS, and PT were ?16.6° (?49.8 %), ?18.7° (?50.3 %), and 18.3° (284.8 %), respectively (P < 0.01). In the sitting position, lumbar lordosis was reduced and pelvic rotation became posterior.ConclusionsThis study showed that LLA decreased by approximately 50 % and PT increased by approximately 25 % in the sitting position compared with the standing position. No significant gender differences were observed for LLA, SS, and PT in the standing position. In the sitting position, however, LLA and SS were markedly larger for women.     

Lumbosacral position sense during pelvic tilting in men and women without low back pain: test development and reliability assessment.

STUDY DESIGN: A single group test-retest design to evaluate the reproducibility of lumbosacral position sense measurements. OBJECTIVES: To develop a measure of position sense in the lumbosacral area and to determine test-retest reliability. BACKGROUND: Proprioception, muscle control, and coordination training could be the key issues in resolving neuromuscular dysfunction in patients with low back pain, but there are no standard ways to assess these parameters. METHODS AND MEASURES: A piezoresistive accelerometer attached to the skin over the sacrum was used to research the repositioning accuracy of active pelvic tilting, between days, of 14 young nonimpaired subjects (20 to 26 years of age) in standing. RESULTS: The mean absolute error for repositioning accuracy (the difference between criterion and matching positions) was 1.81 degrees (+/- 0.85). The intraclass correlation coefficient between measurements obtained on days 1 and 2 was moderate (R = 0.51). The average standard error of measurement associated with the intraclass correlation coefficient was 0.5 degree (95% confidence interval = +/- 0.99 degree). CONCLUSIONS: These findings suggest that the proposed test is sensitive with moderate test-retest reliability to examine lumbosacral position sense in healthy subjects. Further adjustments in the testing protocol are needed to improve the test-retest reliability.     

Spinal Posture of Thoracic and Lumbar Spine and Pelvic Tilt in Highly Trained Cyclists

The aim of this study was to evaluate sagittal thoracic and lumbar spinal curvatures and pelvic tilt in elite and master cyclists when standing on the floor, and sitting on a bicycle at three different handlebar-hand positions. A total of 60 elite male cyclists (mean age: 22.95 ± 3.38 years) and 60 master male cyclists (mean age: 34.27 ± 3.05 years) were evaluated. The Spinal Mouse system was used to measure sagittal thoracic and lumbar curvature in standing on the floor and sitting positions on the bicycle at three different handlebar-hand positions (high, medium, and low). The mean values for thoracic and lumbar curvatures and pelvic tilt in the standing position on the floor were 48.17 ± 8.05°, -27.32 ± 7.23°, and 13.65 ± 5.54°, respectively, for elite cyclists and 47.02 ± 9.24°, -25.30 ± 6.29°, and 11.25 ± 5.17° for master cyclists. A high frequency of thoracic hyperkyphosis in the standing position was observed (58.3% in elite cyclists and 53.3% in master cyclists), whereas predominately neutral values were found in the lumbar spine (88.3% and 76.7% in elite and master cyclists, respectively). When sitting on the bicycle, the thoracic curve was at a lower angle in the three handlebar-hand positions with respect to the standing position on the floor in both groups (p < 0.01). The lumbar curve adopted a kyphotic posture. In conclusion, cyclists present a high percentage of thoracic hyperkyphotic postures in standing positions on the floor. However, thoracic hyperkyphosis is not directly related to positions adopted on the bicycle.

Key points

• This study evaluated thoracic and lumbar spinal curvatures and pelvic tilt in elite and master cyclists while standing and sitting on the bicycle.
• Elite and master cyclists showed a high frequency of thoracic hyperkyphosis and neutral lumbar lordosis in standing.
• Cyclists adopted a significantly lower thoracic kyphosis on the bicycle at the three handlebar positions analysed (upper, middle and lower handlebars) than in standing posture. The lumbar spine showed a kyphotic posture.
• The high percentage of standing thoracic hyperkyphosis in both groups of cyclists may be related to factors other than the specific posture adopted while cycling. Lumbar kyphosis on the bicycle may not affect the sagittal configuration of the lumbar spine in standing.

     

Differences in cervical sagittal alignment between the standing and sitting positions

BackgroundSagittal spinal alignment has mainly analyzed in the standing position. According to previous studies, there are significant differences in lumbopelvic alignment between the standing and sitting positions and cervical alignment is affected by lumbopelvic alignment. In this study, therefore, we hypothesized that cervical sagittal alignments are different between the standing and sitting positions.MethodsA total of 108 patients with spinal degenerative diseases underwent whole spine radiography. Cervical lordosis (CL), C2-7 SVA, T1S, C7–S1 SVA, TK, LL, SS, PT, and PI were measured in the standing and sitting positions. Patients were classified into 3 groups according to the changes in CL (ΔCL, CL in the sitting position − CL in the standing position); ΔCL < −3° (Decreased group: DG; 28.7%), −3° ≤ ΔCL ≤ 3° (Unchanged group: UG; 41.7%), and ΔCL > 3° (Increased group: IG; 29.6%).ResultsThe parameters of the UG in the standing position were closer to the ideal alignment (SRS-Schwab classification). In the DG, CL, T1S, and C7–S1 SVA in the standing position were significantly higher than in the UG. In the IG, PI-LL in the standing position was significantly higher than in the UG. In the sitting position, pelvis was rotated posteriorly (decrease in SS and increase in PT) and lumbar lordosis was flattened (decrease in LL) in all groups, and C2-7 SVA was significantly higher in the DG than in the UG.ConclusionsCL was different between the standing and sitting positions in 58.3% of individuals. However, patients with good spinal sagittal alignment appeared to not undergo any changes in cervical alignment. Our results suggest the possibility that patients who had a positive imbalance and large PI-LL mismatch in the standing position had decreased CL and increased CL, respectively, when in the sitting position.     

Lumbar spine kinesthesia in patients with low back pain.

STUDY DESIGN: Single-group, posttest only, using a sample of convenience. OBJECTIVE: To measure the repositioning error of subjects with low back pain for lumbar sagittal movement using a simple kinesthetic test previously described. BACKGROUND: Patients with low back pain are commonly observed to have difficulty in adopting a mid or neutral position of the lumbar spine. METHODS AND MEASUREMENTS: Twenty subjects with low back pain were required to reproduce an upright neutral posture of the lumbar spine following movement into flexion in a sitting position. Trunk positioning accuracy was measured with an electromagnetic tracking device. RESULTS: The mean absolute value of the repositioning error in the sagittal plane was 2.25 degrees +/-0.88 degrees on day 1 and 2.32 degrees +/-1.62 degrees on day 2. The performance of patients with low back pain was similar to that of asymptomatic patients in a previous study, although subjects with low back pain overshot the neutral position more frequently (79%) than did nonimpaired subjects (50%). CONCLUSIONS: Subjects with low back pain may have attempted to use extra mechanoreceptive cues to compensate for some kinesthetic deficit. Nevertheless, the kinesthetic test used was not sensitive enough to detect any repositioning deficits, and reasons for this are explored.     

Effect of paraspinal muscle vibration on position sense of the lumbosacral spine.

STUDY DESIGN: A two-group experimental design with repeated measures on one factor was used. OBJECTIVES: To investigate the role of the muscle spindles of the paraspinal muscles in lumbosacral position sense of healthy individuals. SUMMARY OF BACKGROUND DATA: Muscle spindles are recognized to be important mediators for position and movement sense in peripheral joints, and they are very sensitive to mechanical vibration. However, little is known about their role in the control of lumbosacral spine positioning. METHODS: Twenty-five young individuals with no low back pain were assigned at random to an experimental or control group. Proprioceptive information of the multifidus muscle spindles was distorted in half of the trials in 16 individuals by manually applying vibration (70 Hz, 0.5 mm amplitude) for approximately 5 seconds. The control group (n = 9) only heard the vibrator noise during repositioning of the lumbosacral spine. Repositioning accuracy in the sitting position was estimated by calculating the mean absolute error, constant error, and variable error among six criteria and reproduction sacral tilt angles. RESULTS: Multifidus muscle vibration induced a significant muscle lengthening illusion through which the members of the experimental group undershot the target position (F(1,15) = 30.77, P < 0.0001). The position sense scores of the control group displayed no significant differences across trials (F(1,8) = 0.56, P > 0.05). CONCLUSIONS: The findings suggest that precise muscle spindle input of the paraspinal muscles is essential for accurate positioning of the pelvis and lumbosacral spine in a sitting posture.     

Influence of patient position on withdrawal forces during removal of lumbar extradural catheters

We have investigated the force required to remove lumbar extradural catheters from 88 parturients to determine the effects of patient positioning at removal, relative to the position at insertion. Parturients were allocated randomly to one of four groups: LS (lateral insertion, sitting withdrawal), LL (lateral insertion, flexed lateral withdrawal), SL (sitting insertion, lateral withdrawal) or SS (sitting insertion, sitting withdrawal). In both positions, the lumbar spine was kept maximally flexed. The force required to remove the catheter was measured at withdrawal. We found that the withdrawal force was influenced by the relationship between the position at removal and that at insertion, and we recommend that for ease of removal, patients should be placed in the same position as they were at the time of insertion. Compared with all other groups, the withdrawal force in patients in group LS was significantly greater (P < 0.05).      

不同上肢体位对正常人和青少年特发性脊柱侧凸患者站立位脊柱矢状面形态的影响

目的 探讨不同上肢体位时,脊柱侧位片上脊柱区域和整体的形态变化,并确定上肢何种体位能更正确地反映脊柱的矢状位形态.方法 研究对象包括特发性脊柱侧凸(adolescent idiopathic scoliosis,AIS)胸弯患者21例和正常青少年志愿者13名.均摄站立位脊柱全长正位X线片及上肢平举及上肢抱胸两种体位的侧位X线片.侧位X线片上测量的参数指标包括:(1)线性距离指标.T1与C-铅垂线(C7 plumb line,C7PL)的距离、胸椎后凸顶点与C7PL的距离、L1与C7PL的距离、腰椎前凸顶点与C7PL的距离、骶骨后上缘与C7PL的距离(SVA);(2)区域前凸及后凸角度的指标.T2～5、T5～12、T10～L2、T1～12、L1～S1、上胸椎后凸(T1上缘与水平线的夹角)、下胸椎后凸(T12下缘与水平线的夹角)、上腰椎前凸(L1上缘与水平线的夹角)、下腰椎前凸(S1上缘与水平线的夹角);(3)骨盆的形态参数:骨盆倾斜角(pelvic tilt,PT)、骶骨倾斜角(sacral slope,SS)、骨盆投射角(pelvic incidence,PI).分别对AIS组及正常组就不同上肢体位时参数的测量结果进行配对t检验.结果 当上肢平举时,AIS组及正常组的腰椎前凸顶点与C7PL的距离、SVA及上胸椎后凸角度均小于上肢抱胸时的测量结果,下胸椎后凸角度及上腰椎前凸角度大于上肢抱胸时的测量结果;另外当上肢平举时,AIS组的腰椎前凸(L1-S1)较上肢抱胸时增大,胸椎后凸顶点与C7PL的距离、L1与C7PL的距离较上肢抱胸减小.结论 双上肢抱胸体位可以更好地反映生理状况下脊柱的矢状面形态.     

Changes in the global spine alignment in the sitting position in an automobile

BACKGROUND CONTEXTStudies of the changes in spine alignment in the sitting position have been limited to specific spine segments. Because there have been few studies of global spinopelvic alignment in the sitting position, it is important to assess the changes associated with this position for such settings as developing future design of seats and achieving appropriate restoration of spine alignment.PURPOSEThis study aimed to measure changes in global spine alignment when people are sitting in car seats and to analyze the characteristics of those changes.STUDY DESIGNThis was a prospective, collaborative study of the radiological evaluation of changes in global spine alignment.PATIENT SAMPLEThe study included 113 asymptomatic adult participants (56 men and 57 women) without a history of spine disease or lower limb surgery, and with no current lower back or leg pain.OUTCOME MEASURESRadiographic findings were assessed by measurement of various angles: cervical lordosis (CL), thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), C7 sagittal vertical axis (C7-SVA), T1 spinopelvic inclination (T1SPI), and T1 pelvic angle (TPA).METHODSRadiographs were obtained in the standing and sitting positions. The objective variables analyzed statistically were spine alignments (CL, TK, TLK, LL, C7-SVA, T1SPI, TPA, SS, PT, and PI) measured in the standing position, body alignments (CL, TK, TLK, LL, C7-SVA, T1SPI, TPA, SS, and PT) measured in the sitting position, and stand-to-sit changes (∆CL, ∆TK, ∆TLK, ∆LL, ∆C7-SVA, ∆T1SPI, ∆TPA, ∆SS, and ∆PT). Explanatory variables were sex, age, body height, and body mass index.RESULTSChanging posture from standing to sitting decreased CL by an average of 5.3°, slightly decreased TK by an average of 1.3°, increased TLK by an average of 6.8°, decreased LL by an average of 35°, decreased SS by an average of 49.2°, increased PT by an average of 49.2°, shifted C7-SVA backward by an average of 106.7 mm, decreased T1SPI by an average of 18.8°, and increased TPA by an average of 21.1°. Statistical analysis revealed that ΔLL was significantly decreased in elderly participants. After the stand-to-sit change, ΔTLK and ∆TPA were significantly increased in taller participants and ΔT1SPI was significantly decreased in taller participants.CONCLUSIONSAmong other changes, most notably LL is decreased and the pelvic tilt is increased when a person is sitting in a car seat. However, these changes in spine alignment differ with age and height. These findings may be useful for the development of future design of seats and for achieving appropriate surgical restoration of spine alignment.     

短节段腰椎融合术后从站位到坐位的脊柱矢状位序列变化

目的:研究短节段腰椎融合术后患者从站位到坐位时的脊柱矢状位序列的变化,以及与正常人群在体位改变时的变化差异,探讨短节段腰椎融合术对不同体位下矢状位序列的影响。方法:回顾性分析2010年~2012年在北京大学第三医院行腰椎融合内固定术的患者资料58例(A组),其中男30例,女28例,年龄63.7±8.5岁(43~81岁),根据术中腰骶是否融合将A组分为腰骶融合组(A1组,26例)与腰骶未融合组(A2组,32例)。对照组为90例中老年健康志愿者(B组),其中男39例,女51例,平均年龄53.2±5.7岁(42~71岁)。所有受试者均行站立位和坐位时的全脊柱X线片检查,应用院内图片存档和通信系统(PACS)测量脊柱矢状位轴(SVA)、T1骨盆角(TPA)、骨盆入射角(PI)、骨盆倾斜角(PT)、骶骨倾斜角(SS)、腰椎前凸角(LL)、胸椎后凸角(TK)。采用独立样本t检验分别比较A组与B组的差异,以及A1组、A2组和B组在站位和坐位时矢状位序列变化的差异。结果:A组患者从站位到坐位时,SVA增加(19.7±33.1mm vs 37.9±27.4mm,P<0.001),TPA增加(11.7°±6.2°vs 17.1°±8.0°,P<0.001),LL减小(41.6°±13.6°vs 35.6°±14.3°,P<0.001),TK减小(30.5°±12.0°vs 28.0°±12.1°,P<0.05),PT增加(15.1°±6.7°vs 19.4°±9.5°,P<0.001),SS减少(32.3°±8.7°vs 28.7°±9.9°,P<0.001)。A组患者LL和TK的减小,以及SVA的增加显著小于B组(P<0.05),其中A1组PT的增加显著小于B组(2.1°±7.1°vs 6.1°±8.9°,P<0.05),而A2组PT的增加程度与B组无统计学差异(6.0°±6.6°vs 6.1°±8.9°,P>0.05)。结论:短节段腰椎融合术后的脊柱从站位到坐位时表现为骨盆后旋,胸、腰椎曲度变直,脊柱矢状轴前移,但其胸腰椎曲度变化和矢状轴前移的幅度显著小于对照组。短节段腰椎融合术会限制坐位时骨盆的后旋。     

The standing and sitting sagittal spinopelvic alignment of Chinese young and elderly population: does age influence the differences between the two positions?

To investigate the characteristics of standing and sitting spinopelvic sagittal alignment among Chinese healthy population with different age groups. This cross-sectional, prospective study included a total of 235 volunteers aged 19 to 71 years. Volunteers were divided into two groups: group A (age ≤ 40 years; n = 140) and group B (age > 40 years, n = 95). Student’s t test was performed to compare the sagittal parameters including sagittal vertical axis (SVA), T1 pelvic angle (TPA), cervical lordosis (CL), thoracic kyphosis (TK), lumbar lordosis (LL) and pelvic tilt (PT) between standing and sitting positions of two groups. Multiple regression was performed to explore the influence factors of differences between two positions. In the standing position, group B had larger SVA, TK, PT and TPA than group A. When moving from standing to sitting position, increased SVA and PT were found in both groups, accompanied by decreased LL and TK. However, despite similar change in SVA, group B presented with lesser changes in LL, PT and TPA than group A in sitting position. Age and gender independently influenced the difference in PT and LL. In the standing position, the older volunteers showed larger SVA, TPA, TK, CL and PT than young population. Both groups showed similar changes when moving from standing to sitting, but the differences between the positions were smaller in older population. These characteristics in the standing and sitting positions of different age groups should be considered when planning surgical reconstruction of sagittal alignment. These slides can be retrieved under Electronic Supplementary Material.     

Urethral closure pressure profiles in the standing position: Are they necessary?

The aim of the study was to assess the sensitivity for urodynamic abnormalities of both static and dynamic urethral closure pressure profiles done in the sitting and standing positions. Multichannel urethral closure pressure profilometry (UCPP) was performed on 21 patients complaining of stress incontinence. Two clinical groups were identified, those with mild to moderate and those with severe incontinence. The parameters of both the static and the dynamic UCPPs obtained in the sitting and standing positions were compared for sensitivity to urodynamic abnormalities. Non-parametric statistical methods were used (Wilcoxon signed rank test; Mann-Whitney test.) No statistically significant differences were found in the mean maximum urethral closure pressures (MUCPs) in the two positions. Patients with a clinical diagnosis of severe incontinence had decreased MUCPs in both positions. It was therefore concluded that the urethral closure pressure profile may be measured in the sitting position without compromising the results.Editorial Comment: It is well known that various parameters measured in the urethral closure pressure profile are affected by both posture and degree of bladder filling. In the normal stress continent person, more upright posture and greater bladder filling both produce an increase in closure pressure, whereas the stress incontinent person has lost the ability to compensate for these stresses on the continence mechanism, and a deterioration in closure pressure results. This article concludes that the sitting position is enough to obtain the maximal effect and that it is not necessary to resort to the standing position to see maximal deterioration of closure pressure in the stress incontinent female.     

Can Flexed-Seated and Single-Leg Standing Radiographs Be Useful in Preoperative Evaluation of Lumbar Mobility in Total Hip Arthroplasty?

BackgroundThe purpose of this study is to determine whether simulated radiographs in the “flexed-seated” or “step-up” positions better demonstrate a patient’s range of spinopelvic motion between standing and sitting positions than relaxed sitting and standing radiographs.MethodsAn institutional review board approved cohort of 43 patients with hip osteoarthritis whom underwent full body sitting-standing radiographs from August 2016 to December 2017 at a single institution was reviewed. Subjects underwent single-leg step-up standing and flexed-seated radiographs, and relaxed standing and sitting radiographs. Sacral slope, spinopelvic tilt (SPT), and lumbar lordosis were measured in all radiographs. Alignment parameters were compared between both sets of imaging, and the change in SPT between the imaging modalities was plotted and stratified by pre-existing lumbar pathology.ResultsThere were significant differences between the relaxed standing and step-up radiographs and the relaxed and flexed-seated radiographs for sacral slope, SPT, and lumbar lordosis (P < .002 for all), with the exception of SPT in the relaxed and step-up standing postures (P = .110). When transitioning from the standing to sitting position, the mean changes in SPT differed significantly between both sets of radiographs. Most importantly, when plotting changes in SPT between flexed and relaxed sitting postures, patients with fusions and flatback deformity trended toward greater anterior pelvic tilting, a position of greater risk of posterior dislocation.ConclusionFlexed sitting and single-leg standing imaging may emphasize the compensatory mechanisms of patients with concomitant hip and spine pathology more than relaxed imaging using our measurements. Our method may provide insight into high dislocation risk patients compared to the previously published hip measurement method.Level of EvidenceIII.     

Effect of test position on pelvic floor muscle assessment

The aims of this study were to analyse the effect of different body positions on pelvic floor muscle (PFM) assessment using digital muscle testing, manometry and transabdominal ultrasound. In addition, subject acceptance of each testing position was recorded. Subjects were 20 women's health physiotherapists. The testing protocol included the best of three maximum voluntary contractions tested in each of four positions (crook lying, supine, sitting and standing). Significant differences in muscle strength and subject acceptance between positions were found with each tool, most often between lying and upright positions. Digital muscle testing and vaginal squeeze-pressure scores were highest in the lying position, and vaginal resting pressure and transabdominal ultrasound scores were highest in the standing position. Subjects preferred the lying positions for internal examinations. The clinical significance of these differences and the reasons for these variations require further investigation.     

Effect of intraoperative position used in posterior lumbar interbody fusion on the maintenance of lumbar lordosis

OBJECT: The objective in this study was to compare retrospectively the use of different operating tables with different positions for posterior lumbar interbody fusion (PLIF) and the effect on intraoperative and postoperative lumbar lordosis and segmental lordosis. METHODS: One hundred seventy-two patients with degenerative disease of the lumbar spine who underwent posterior decompression and PLIF in which a 0 degrees polyetheretherketone cage and pedicle screw fixation were used were evaluated. Ninety-one patients underwent surgery on a Wilson table (Group I) and 81 patients were treated on an OSI Jackson spinal table (Group II). Preoperative standing, intraoperative prone, and postoperative standing lateral radiographs were obtained in each patient. The total lumbar and segmental lordosis were compared and analyzed according to the position in which the patients were placed for their operation. RESULTS: The intraoperative total lumbar lordosis was significantly decreased compared with the preoperative value. The postoperative total lumbar lordosis was similar, however, to the preoperative values in both groups. In Group I, the intraoperative segmental lordosis of L2-3 and L3-4 was significantly decreased compared with the pre-operative segmental lordosis. In Group II, the intraoperative segmental lordosis of L3-4, L4-5, L5-S1, and L4-S1 was significantly decreased compared with the preoperative segmental lordosis. The postoperative segmental lordosis of L4-5 was significantly decreased and L2-3 was significantly increased compared with the preoperative lordosis in both groups. CONCLUSIONS: Intraoperative position does not affect postoperative total lumbar lordosis and segmental lordosis in short-segment PLIF of the lumbar spine in a retrospective analysis of the surgical procedure to maintain lordosis.     

Total Hip Arthroplasty Patients With Fixed Spinopelvic Alignment Are at Higher Risk of Hip Dislocation

Background

Sitting radiographs have been used as a pre-operative tool to plan patient-specific total hip arthroplasty (THA) component position that would improve hip stability. Previous work has demonstrated that spinal mobility may impact functional acetabular position when seated. We sought to determine whether patients who dislocate following THA have different sitting spinopelvic alignment or acetabular component orientation compared to patients who did not dislocate.

The effects of a temporarily manipulated dental occlusion on the position of the spine: a comparison during standing and walking

Background context

The relationship between dental occlusion and body posture or even the spine position is often analyzed and confirmed. However, this relationship has not been systematically investigated for standing and walking.

Purpose

To examine whether a symmetric or asymmetric dental occlusion block, using 4 mm thick silicon panels, can significantly change the spine position (cervical, thoracic, or lumbar region) during standing and walking.

Study design

The following study is a cross-sectional study.

Patient sample

This study was carried out with 23 healthy subjects (18 women, 5 men) without discomfort in the temporomandibular system or body movement apparatus.

Outcome measures

Position changes (millimeter) of the spine (cervical, thoracic, lumbar) in frontal, sagittal, and transverse planes of motion.

Methods

The upper spine position was quantified with an ultrasonic distance measurement system (sonoSens Monitor). Every subject placed the 4 mm thick silicon panel systematically between the left/right premolars or the front teeth. Differences between the habitual and manipulated occlusion positions were determined by the Friedman test, followed by pairwise comparisons with applied Bonferroni-Holm correction.

Results

During standing and walking there were significant (p≤.05) differences between the occlusion block conditions and the habitual dental position in all body planes except in the right lumbar region during walking. In addition, differences within the manipulated occlusion position could be detected. Significant differences were also shown between the standing and walking trials in the frontal, sagittal, and transverse planes, particularly with respect to the lumbar region (p≤.001).

Conclusions

Symmetrical and asymmetrical occlusion blocks in the premolar region can be associated with changes in all three spine regions during standing and walking. The results showed highly similar reaction patterns in all spine positions, regardless of the location of the silicon panel. Between standing and walking, the main differences were in the lumbar spine. The results suggest a relationship between the chewing and the movement system. However, it must be stated that this study has no direct clinical impact. The study design cannot determine the causality of the observed associations; also the clinical significance of the small postural changes remains unknown.     

Voiding position does not affect uroflowmetric parameters and post-void residual urine volume in healthy volunteers

OBJECTIVE: To investigate the effect of voiding position using uroflowmetry and post-void residual (PVR) urine volume assessment in healthy men and women. MATERIAL AND METHODS: The study population comprised 72 healthy volunteers. The mean (range) ages of the male (n = 36) and female (n = 36) subjects were 30 (18-40) years and 32 (21-44) years, respectively. The uroflowmetric studies were repeated in the standing, sitting and crouching positions for men and in the sitting and crouching positions for women. At least three measurements were obtained for all voiding positions for each volunteer. PVR volumes were measured using trans-abdominal ultrasound after each voiding. Maximum flow rate (Qmax), average flow rate (Qave), voided volume (VV) and PVR values obtained in each voiding position were compared with those obtained in the other positions. Comparisons were done using one-way ANOVA. RESULTS: The mean Qmax and Qave values obtained in the sitting, crouching and standing positions in men were 24.29 +/- 0.73 and 15.67 +/- 0.37, 23.28 +/- 0.64 and 15.56 +/- 0.33, and 23.58 +/- 0.63 and 15.81 +/- 0.34 ml/s, respectively. The mean VV and PVR values obtained in the sitting, crouching and standing positions in men were 297.5 +/- 12.71 and 13.52 +/- 1.02, 306.3 +/- 13.46 and 14.02 +/- 1.08, and 309.9 +/- 13.14 and 12.92 +/- 0.95 ml, respectively. In women, the mean Qmax and Qave values obtained in the sitting and crouching positions were 28.09 +/- 0.66 and 18.26 +/- 0.36, and 27.98 +/- 0.59 and 17.31 +/- 0.35 ml/s, respectively. The mean VV and PVR values obtained in the sitting and crouching positions in women were 331.8 +/- 13.28 and 11.82 +/- 0.99, and 326.9 +/- 12.87 and 12.79 +/- 1.07 ml, respectively. There were no significant differences in any of the parameters between voiding positions in either group. CONCLUSION: Urinary flow rates and PVR urine volume do not seem to be affected by voiding position in healthy men and women.     

The effects of a 3-week use of lumbosacral orthoses on proprioception in the lumbar spine

STUDY DESIGN: Longitudinal, repeated-measures, factorial design. The trunk axial rotation repositioning error was the dependent variable, while the orthoses, test mode (passive versus active), and the testing session were the independent variables. OBJECTIVES: To verify whether lumbosacral orthoses (LSOs) affect proprioception in the lumbar spine and whether these effects change over a 3-week period during which the LSO is consistently worn. BACKGROUND: To date, there is no compelling evidence that lumbar orthoses support the spine. One hypothesis advanced by several authors is that they may enhance position sense (proprioception) in the lumbar spine. METHODS AND MEASURES: Fourteen subjects without low back pain wore lumbosacral orthoses 3 hours a day for 3 weeks. Spine proprioception was tested in a seated posture in 3 sessions (days 0, 7, and 21). RESULTS: A significant 3-way interaction was found between the effects of the orthoses, session, and test mode (P = .03). The ratio of passive to active average error indicated that after 3 weeks of wearing LSO, proprioception in the passive test worsened in relation to the active test with the LSO. In contrast, proprioception in the passive test improved in relation to the active test when performed without the LSO. CONCLUSIONS: The LSO did affect proprioception in the lumbar spine. These effects most likely changed over time due to sensorimotor adaptation. However, no overall proprioceptive benefits could be ascertained from healthy subjects wearing the LSO.