Construct validity of center of rotation in differentiating of lumbar segmental instability patients.

PURPOSE: Lumbar Segmental Instability (LSI) is a subgroup of nonspecific Low Back Pain (NSLBP) without any accepted diagnostic tool as a gold standard. Some authors emphasize on quality measure such as centre of rotation (COR) but construct validity of this measure had not been approved. Therefore the purpose of the present study was to evaluate Concurrent and Convergent validity of COR in differentiating LSI. METHODS: A total of 66 volunteered males participated in three groups named control, NSLBP and LSI groups based on clinical examination. Patients were diagnosed as LSI according to screening criteria adopted by Hicks et al. Study variables included CORs of lumbar segments in sagittal plane. Three x-rays were taken in neutral, flexion and extension positions. The variables were calculated using CARA software. The ANOVA and Tukey test were utilized in statistic analysis. RESULTS: ANOVA results demonstrated mean differences between three groups for COR of L4 motion segment in y axis (p= 0/008) and L5 motion segment in y axis (p= 0/005) were significant. Tukey test showed significant difference for COR of L4 motion segment in y axis between LSI and healthy groups (p= 0/038) and between LSI and NSLBP groups (p= 0/009). For COR of L5 motion segment in y axis, tukey test demonstrated mean difference between LSI and healthy groups (p= 0/028) and between LSI and NSLBP groups (p= 0/007) were significant. Tukey test did't show any significant difference between NSLBP and healthy groups for COR of L4 (p= 0/852) and L5 (p= 0/871) motion segments in y-axis. CONCLUSIONS: The COR has ability to differentiate patients with signs and symptoms of LSI from other NSLBP and healthy subjects based on the present study results. However, more researches are needed to develop and support results of this study.

The effects of stabilizing exercises on pain and disability of patients with lumbar segmental instability.

BACKGROUND DATA: Lumbar segmental instability (LSI) is one of the subgroups of non-specific chronic low back pain. Pain, functional disability and reduced muscle endurance are common in such patients. OBJECTIVE: The aim of this study was to determine the effects of stabilization exercise on pain, functional disability and muscle endurance in patients with LSI. METHODS: A randomized clinical trial was carried out on 30 patients who had LSI aged between 18-45 years. They were divided into two groups; the control group underwent routine exercise only while the experimental group performed routine exercise plus stabilization training for 8 weeks. Both had 3 months follow-up. The variables included pain intensity, functional disability and flexion and extension range of motion and flexor, extensor and lateral flexor muscles endurance which were evaluated 3 times; before, post treatment and after three months. The data were analyzed using repeated measurement ANOVA. RESULTS: The results revealed that after treatment, the trunk muscle endurance and flexion range of motion increased significantly and the pain intensity and functional disability decreased significantly in both groups; however the rate of improvement was significantly higher in the experimental group. The process of decreasing pain intensity and functional disability in addition to increasing muscle endurance time %was were significantly faster in the experimental group during the three months follow up. CONCLUSION: Regarding the positive effects of stabilizing exercises with routine exercises in reduction of pain intensity, increasing functional ability and muscle endurance, it is recommended to use this method in treatment of patients with lumbar segmental instability.

The validity of vertebral translation and rotation in differentiating patients with lumbar segmental instability.

BACKGROUND AND PURPOSE: Lumbar segmental instability (LSI) is a sub-group of non-specific low back pain (NSLBP), without any accepted diagnostic tool as a golden standard. Some authors emphasize on clinical findings, and others focus on vertebral translation and rotation, but construct validity of these measures had not been approved. Therefore, the purpose of the study was to evaluate convergent and known group validity of vertebral translation and rotation in differentiating LSI from NSLBP and control subjects. METHODS: Study variables included full-range and mid-range vertebral translation and rotation in sagittal plane. Five x-rays were taken in neutral, full flexion and extension and mid-flexion and mid-extension positions of lumbar spine. The variables were calculated using Computer Aided Radiographic Analysis of Spine (CARA) software after scanning. Sixty-six volunteered males participated in three groups. Twenty-two subjects were in the control group, and 44 NSLBP were divided into LSI and not LSI groups according to the criteria adopted by Hicks et al. The ANOVA and Tukey test were used in statistic analysis. RESULTS: ANOVA results demonstrated differences in three groups; for full-range translation and rotation, were not significant. However, the results of ANOVA demonstrated significant difference in L4-5 mid-range translation and rotation (p < 0/05). Tukey test showed significant difference for L4-5 mid-range translation between control (2.14 mm) and LSI (1.33 mm) groups (p < 0/05). Tukey test demonstrated difference between the control (14.18°) and LSI (11.65°) groups (p < 0/05); the control and not LSI (10.80) groups (p < 0/05) were significant for L4-5 mid-range rotation. CONCLUSIONS: On the basis of the study results, the full-range translation and rotation cannot differentiate LSI from not LSI and control groups. Moreover, the mid-range translation only differentiates control from LSI, whereas mid-range rotation differentiates control from both LSI and not LSI.

Reliability of quality measures of movement in lumbar spine flexion-extension radiography.

BACKGROUND DATA: For center of rotation (COR) and centroid length variables in lumbar flexion-extension radiography, enough reliability information is not available. OBJECTIVE: The objective of this study was to determine the intra-rater reliability of COR and centroid length of lumbar intervertebral movement. METHODS: A methodological research for reliability was designed. Fifteen males with chronic non specific low back pain aged between 22-43 years participated in this study. Study variables included COR of full, flexion and extension arc and centroid length. The proposed method from Putto was used for flexion-extension radiography. Five x-rays were taken in neutral, full flexion and extension, mid-flexion and mid-extension positions. The variables were calculated using Computer Aided Radiographic Analysis of Spine (CARA) software after scanning. The intraclass correlation coefficient (ICC) and standard error of measurement (SEM) were utilized for relative and absolute reliability respectively. RESULTS: The results demonstrated high ICC values on x axis (range: 0.67-0.88) and y axis (range: 0.55-0.90) for full arc COR, high ICC values of flexion arc COR on x axis (range: 0.54-0.97) and y axis (range: 0.48-0.99). ICC values results of extension arc ranged between 0.19-0.60 for x axis and 0.16-0.83 for y axis. ICC values for centroid length ranged between 0.22-0.88. CONCLUSION: Results support previous studies which show very high reliability of full arc COR. In addition, flexion arc COR has desirable reliability and low measurement errors. But, extension arc COR and centroid length have moderate reliability and large measurement errors.

Kinematic analysis of dynamic lumbar motion in patients with lumbar segmental instability using digital videofluoroscopy.

The study design is a prospective, case-control. The aim of this study was to develop a reliable measurement technique for the assessment of lumbar spine kinematics using digital video fluoroscopy in a group of patients with low back pain (LBP) and a control group. Lumbar segmental instability (LSI) is one subgroup of nonspecific LBP the diagnosis of which has not been clarified. The diagnosis of LSI has traditionally relied on the use of lateral functional (flexion-extension) radiographs but use of this method has proven unsatisfactory.Fifteen patients with chronic low back pain suspected to have LSI and 15 matched healthy subjects were recruited. Pulsed digital videofluoroscopy was used to investigate kinematics of lumbar motion segments during flexion and extension movements in vivo. Intersegmental linear translation and angular displacement, and pathway of instantaneous center of rotation (PICR) were calculated for each lumbar motion segment. Movement pattern of lumbar spine between two groups and during the full sagittal plane range of motion were analyzed using ANOVA with repeated measures design. Intersegmental linear translation was significantly higher in patients during both flexion and extension movements at L5-S1 segment (p < 0.05). Arc length of PICR was significantly higher in patients for L1-L2 and L5-S1 motion segments during extension movement (p < 0.05). This study determined some kinematic differences between two groups during the full range of lumbar spine. Devices, such as digital videofluoroscopy can assist in identifying better criteria for diagnosis of LSI in otherwise nonspecific low back pain patients in hope of providing more specific treatment.