|Year : 2022 | Volume
| Issue : 1 | Page : 21-26
Slump sitting X-ray: A screening tool in degenerative lumbar spine
Sanjay Dhar, Anirudh Kumar, Sachin Yashwant Kale, Sachin Kandagatla, Akshat Pandey, Taarini Johri
Department of Orthopaedics, Dr. D.Y. Patil Deemed to be University School of Medicine, Nerul, Navi Mumbai, Maharashtra, India
|Date of Submission||01-Oct-2021|
|Date of Decision||07-Sep-2022|
|Date of Acceptance||28-Oct-2021|
|Date of Web Publication||19-Sep-2022|
Sachin Yashwant Kale
Department of Orthopaedics, Dr. D.Y. Patil Deemed to be University School of Medicine, Nerul, Navi Mumbai 400706, Maharashtra
Source of Support: None, Conflict of Interest: None
Study Design: This was a prospective study. Purpose: The aim of this study was to introduce a new slump sitting method radiographs and to compare the angular range of motion (ROM) and displacement between conventional flexion view method and slump sitting radiograph. Overview of Literature: Most patients have mechanical low back pain and lumbar instability is considered to be responsible for most chronic and recurrent pain. Dynamic radiographs have been used to identify spinal instability. Methods: After ethics committee permission, this study was initiated. Sixty patients were enrolled in the study after obtaining written informed consent. Patients were randomly allocated into two groups: the first group underwent slump view then conventional view, and the second group underwent conventional view then slump view followed all patient’s extension radiographs taken. Angular and displacement measurements of the lumbar spine were carried out and compared. Results: Of 60 patients, 40 patients and 26 patients were found instability with slump radiographs and conventional flexion radiographs, respectively. When slump and conventional method were compared, the lumbar flexions were larger in slump radiographs. There were 22.35° of additional global flexion (L1/S1) (P < 0.0001) in slump radiographs when compared with conventional radiographs. Greater global flexion using slump method was found at all lumbar segments with L1/L2 contributing 1.15°; P = 0.009, L2/L3 contributing 3.41°; P < 0001, L3/L4 contributing 5.25°; P < 0.001, L4/L5 5.23°; P < 0.001 with the main contributor being L5/S1 7.41°; P < 0001. When slump and conventional method were compared in terms of displacement, there were no significant differences. Conclusion: The slump siting radiographs in lumbar spine instability effectively show the increase in global flexion with significant improvement in segmental flexion. Slump siting radiograph produces more stress in the entire lumbar spine, especially in lower lumbar spine to diagnose lumbar spine instability. Hence, slump sitting dynamic radiograph was shown to be superior to the conventional forward flexion method in measuring the angular ROM and noninferior to the conventional method in the measurement of displacement
Keywords: Degenerative, dynamic views, instability, slump sitting view, standing flexion
|How to cite this article:|
Dhar S, Kumar A, Kale SY, Kandagatla S, Pandey A, Johri T. Slump sitting X-ray: A screening tool in degenerative lumbar spine. D Y Patil J Health Sci 2022;10:21-6
|How to cite this URL:|
Dhar S, Kumar A, Kale SY, Kandagatla S, Pandey A, Johri T. Slump sitting X-ray: A screening tool in degenerative lumbar spine. D Y Patil J Health Sci [serial online] 2022 [cited 2022 Oct 6];10:21-6. Available from: http://www.dypatiljhs.com/text.asp?2022/10/1/21/356517
| Introduction|| |
Low back pain (LBP) is a problem in modern societies and it is not possible to identify the specific pathoanatomical causes in majority of cases. Patients in which a specific pathoanatomical diagnosis cannot be made are often described as “mechanical” LBP. Many clinicians and researcher suggest that lumbar spine segmental instability is a possible cause of the pathomechanical mechanism underlying mechanical LBP.,
Lumbar spine instability is defined as abnormal lumbar motion during physiological loading of spine. It is loss of the ability of spine under physiological loads to maintain relationships between the vertebra in such a way that there is neither initial damage nor subsequent irritation to the spinal cord or nerve roots and, in addition, there is no development of incapacitating deformity or pain due to structural changes and is characterized by abnormal lumber motion segments beyond normal constraints.
Radiological diagnosis of sagittal lumbar spine instability is dependent on abnormal movement in dynamic flexion and extension radiographs and cannot be fully appreciated in a static lumbar radiograph. However, current methods of performing these radiographs are not standardized and are not sufficiently optimized to identify instability. The standing forward bending position is currently the most conventional posture used to obtain flexion radiographs in dynamic X-rays of the lumbar spine. Other less common protocols include the lateral decubitus and supine postures. The lateral decubitus X-ray posture is unable to provide a weight-bearing assessment of the lumbar spine.
Although the presence or absence of this instability often influences the surgical decision and predicts outcome, this radiological investigation has been poorly studied and there are no established guidelines to reliably diagnose spinal instability.
In presence of spinal instability, the symptomatic patient may require decompression with spinal fusion. These surgical procedures tend to have greater blood loss, a longer hospital stay, and higher cost.
These spinal procedures may result in some long-term sequelae such as loss in range of motion (ROM) and accelerated degeneration of adjacent segments.
So, it is important to adequately assess for lumbar spine instability to avoid any spinal surgery.
Various imaging modalities have been used including X-rays, computed tomographic (CT) scan, and magnetic resonance imaging (MRI) scan.
The X-ray is an appropriate imaging modality for this purpose as it is affordable, readily available, and provides adequate assessment of bony details for this diagnostic purpose.
To examine the optimal position to evaluate the lumbar spine in flexion through its physiological ROM, this study compares the slump sitting posture against the conventional standing forward bending posture. As slump sitting posture is a physiological posture that people assume in daily life, it has been shown that it results in greater lumbar flexion compared with the standing, forward bending posture.
Aims and objectives
The aim this study was to introduce a new slump sitting method for performing optimal lumbar spine flexion radiographs and to compare the angular ROM and displacement between the conventional flexion view method and this new method.
| Materials and Methods|| |
Place of study: Dr. D. Y. Patil Medical College, Hospital and Research Centre, Navi Mumbai, Maharashtra.
Period of study: 2017–2019.
Sample size (n): A total of 60 patients.
Type of study: Prospective study.
The study was approved by the local ethical committee and the patients gave their informed consent to participate.
Patients above 48 years of age.
Patients with mechanical LBP.
Patients with spondylolisthesis on standard lateral radiographs.
Patients who were physically able to position themselves correctly for both methods of X-rays.
Previous spinal intervention.
Suspected finding for spinal malignancies, spinal trauma, and inflammatory spinal diseases.
Method for statistical analysis
This was a prospective, comparative study.
Sixty subjects participated in a prospective, single-blinded, randomized, controlled trial comparing the lumbar spine flexion between the conventional method and the new method.
During the clinical consultation in out-patient and in-patient, history was taken as per a usual clinic visit. Patient’s details including age, occupation, presence, and severity of back pain, presence and severity of leg pain, and neurologic status were noted. Physical examination was performed.
Both the slump-sitting and conventional flexion methods were performed on each patient. Pictures of both methods are shown in [Figure 1]A and B. These pictures were provided to the subjects as instruction guides during the radio imaging process and the visual guides were reinforced with verbal instructions from the on-duty radiographers. Images were obtained with the X-ray beam projected from the patient’s left and at a distance of 100 cm from the patient with central beam was directed at the estimated center of L3, with T11 vertebral body and mid-body of the sacrum serving as superior and inferior limits, respectively. An extension view of the lumbar spine was also performed after these views. All radiographs were stored on digital imaging and communications in medicine format for assessment. For the conventional (standing forward bending) method, the following standardized instructions were given to the patients. “Stand with both feet placed together, hands behind your head, and bend forward in this position as much as possible without falling.” For the slump sitting method, the chair was adjusted to allow patients to sit at 90° of flexion of the hips and knees. The following standardized instructions were then given to the patients. “Sit slumped on the chair as much as possible without leaning forwards; place your hands below the thighs.”
|Figure 1: (A and B) Model showing the position of patient in slump sitting (left) and standing flexion (right) position|
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The Cobb method was used for all angular measurements and referenced to the superior endplates of each vertebra [Figure 2]A–C. For the global lumbar lordosis, measurements were taken from L1 to S1. Segmental measurements were also taken from L1–L2, L2–L3, L3–L4, L4–L5, and L5–S1. This was repeated for both conventional and new methods of flexion X-rays and extension X-ray. The global and segmental lumbar angulations were obtained by subtracting the angle subtended by the extension radiographs from the angles subtended by the flexion radiographs, with lordosis given a negative value and kyphosis given a positive value.
|Figure 2: Angular measurements of the flexion and extension radiographs: (A) slump sitting, (B) standing flexion, and (C) standing extension|
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The presence of vertebral displacement and its magnitude were recorded for all three groups of radiographs [Figure 3]A and B. The extent of sagittal translation was obtained by calculating the difference in vertebral displacement between the extension radiographs and the flexion radiographs, with spondylolisthesis given a positive value and retrolisthesis given a negative value. Both absolute values and ratios of displacement were calculated using the lengths of the caudal vertebral superior endplates.
|Figure 3: Displacement measurements of the flexion radiographs: (A) standing flexion and (B) slump sitting|
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All collected data and measurements were tabulated using Microsoft Excel 2010 and statistical analysis was done with the Statistical Package for the Social Sciences (SPSS, Chicago, IL, USA) software program using the Student’s t test. The parameters evaluated included patient age, gender, American Society of Anesthesiologists (ASA) grade, presence and severity of leg pain, duration of each pain, presence of paravertebral muscle tenderness, Schober’s test, hamstring tightness, and Beighton ligament laxity score. Global and segmental lumbar flexion, as well as the measured displacements obtained between the two groups, was also performed using unpaired t test to further ensuring that no coincidental confounders could affect the final result and that the differences between the new and conventional methods of flexion would be truly comparable.
Analysis of both global and segmental lumbar flexion, as well as the measured displacements obtained between both views, paired t test was used. Lastly, the odds ratio and possible predictive value of each parameter (with a larger global lumbar flexion on a radiograph done using the new method) were calculated. This was performed by multivariable linear regression modeling based on a positive outcome defined as a larger global flexion using the new method.
| Results|| |
Of 60 patients, 32 were men and 28 were women with a mean age of 57.07 years. There were no significant differences in parameters studied: patient age, gender, ASA grade, presence and severity of back pain and leg pain, duration of each pain, presence of paravertebral muscle tenderness, Schober’s test, and Beighton laxity score [Table 1] and [Table 2].
Diagnostic criteria suggested by White and Punjabi were applied.
Of 60 patients, 40 patients and 26 patients were found instability with slump radiographs and conventional flexion radiographs, respectively [Table 3].
|Table 3: Percentage of patients with diagnosis of spinal Instability made by dynamic radiograph|
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Some patients had instability at multiple levels. At L1/L2, 3% and 0%; at L2/L3, 11.7% and 0%; at L3/L4, 20% and 0%; at L4/L5, 18.3% and 13.3%; and at L5/S1, 33.7% and 31.75% patients had instability in slump and conventional flexion radiographs, respectively [Table 3].
When slump and conventional method were compared, the lumbar flexions were larger in slump radiographs. There were 22.35° of additional global flexions (L1/S1; P < 0.0001) in slump radiographs as compared with conventional radiographs [Table 4]. Greater global flexion using slump method was found at all lumbar segments with L1/L2 contributing 1.15°; P = 0.009, L2/L3 contributing 3.41°; P < 0001, L3/L4 contributing 5.25°; P < 0.001, L4 L5 5.23°; P < 0.001 with the main contributor being L5/S1 7.41°; P < 0001.
|Table 4: Comparison of flexion angle between slump and conventional standing flexion|
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When slump and conventional methods were compared in terms of displacement, there were no significant differences in both methods [Table 5].
|Table 5: Comparison of percentage displacement between slump and conventional standing flexion method|
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| Discussion|| |
Lumbar spine instability is an important cause of LBP and disability when associated with neuropathy. The most common cause of instability is degenerative in elderly population, which is associated with olisthesis and canal stenosis. The degenerative cascade proposed by Kirkaldy-Willis et al. is believed to be involved in the pathophysiology of spinal degenerative diseases, including degenerative lumbar spondylolisthesis and canal stenosis. If the optimal diagnosis of lumbar instability has not been done and patients were treated with only decompression surgery, these would develop symptoms in future due to instability. These are the patients who developed symptoms in future due to instability. As the symptom had developed due to abnormal movement, decompression only will not resolve the symptom unless spine is stabilized and fused. So, it is very important to diagnose the lumbar instability. The current method is conventional standing forward bending radiograph, which is the most commonly used dynamic radiographs.
Many guidelines recommend spine fusion in patients with instability. There were many studies regarding treatment for lumbar spinal instability and degenerative spondylolisthesis.,,,,,,,, Study shows low-grade spondylolisthesis or a hypermobile segment >10° had good outcome after operative treatment and fusion.
There are many radiographic diagnostic criteria for assessing lumbar spine instability which includes sagittal plane angular movement and vertebral translation.,,,,,
These criteria for sagittal plane translation are more than 4.5 mm or 15% of size of the end plate and for rotational instability are greater than 15° at L1 to L4, greater than 20° at L4–L5, and greater than 25° at L5–S1. These are the most acceptable criteria.
As there is no standardization for diagnosis of instability, which results in further investigation like plane radiograph in different posture, CT scan, and MRI. CT scan and MRI are not readily available everywhere and if available these are not affordable in most population. Plain radiograph is readily available modalities that give a good assessment of bony details.
Many other studies with different posture like side bending with traction compression radiographs are proposed.,,,,,,,,,,,
Slump sitting posture is a weight-bearing posture that simulates the physiological biomechanics of the spine and stresses the spine into flexion. Sitting posture is more stable posture than standing. Many patients with muscle weakness, giddiness may have apprehensive when doing forward standing bending, thus limiting the final effort in an attempt to maintain balance. Sitting posture theoretically reduces the risk of falls and injuries. Patients in sitting positions have a lower center of gravity and no need to support their own weight; this would be useful in patients with leg weakness or those unsteady on their feet. As safety has enhanced, this posture allows the patient to push into maximum possible flexion, and thus more likely to reflect a true stress view of spine. Patients with hamstring tightness and lower limb deformities or injury that render standing difficult, may limit the extent of forward bending. In slump sitting hip is in 90° of flexion which reduces the hip movements so this position can force the spine specifically into greater flexion to show instability.
Compared with other advanced imaging like CT scans have added advantage of three-dimensional visualization and have high resolution of bony details. CT scan is more expensive, has higher radiation exposure, and is unable to assess in a weight-bearing posture. The MRI gives assessment of ligamentous integrity and presence of fluid in within facets joint, which give presence of instability but not ideal for assessment of bony details.
A study done by Hey et al. to compare slumps sitting and forward bending radiograph showed the similar results.
In this comparative study, there is improvement in global flexion of the lumbar spine using slump sitting radiographs. The results show that even segmental flexion in L1/L2, L2/L3, L3/L4, L4/L5, and L5/S1 was statistically significant. Flexion was greatest at L5/S1 (7.41°; P < 0.0001), followed by L3/L4 (5.25°s; P < 0.0001), and L4/L5 (5.23°s; P < 0.0001). This suggests that slump sitting radiograph is effective in stressing the entire lumbar spine, especially in the lower lumbar spine.
In this study, there is no significant advantage in terms of showing vertebral translation compared to conventional forward bending radiographs. There are some reasons to explain this. First, the patient taken for this study had back pain with or without spondylolisthesis. Most of the patients had only LBP and were not be able to show listhesis unless the study was done with only spondylolisthesis. Second, the patient with spondylolisthesis had nutcracker effect. On forward bending X-rays, paradoxically the translated vertebra brought into extension rather than flexion.
| Conclusion|| |
The slump sitting radiographs in lumbar spine instability effectively show the increase in global flexion with statistically significant improvement in segmental flexion. There is no significant advantage in vertebral translation. This study shows that slump siting radiographs produce more stress in the entire lumbar spine, especially in lower lumbar spine to diagnose lumbar spine instability. Hence, slump sitting dynamic radiograph was shown to be superior to the conventional forward flexion method in measuring the angular ROM and noninferior to the conventional method in the measurement of displacement.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]