|Year : 2013 | Volume
| Issue : 4 | Page : 230-236
Clinical effects of short and long lever spinal thrust manipulation in non-specific chronic low back pain: A biomechanical perspective
S Gopal Nambi1, Dipika Inbasekaran2, Ratan Khuman1, Surbala Devi1, Kalpesh Satani1
1 Department of Physiotherapy, C.U. Shah Physiotherapy College, Surendranagar, Gujarat, India
2 Department of Physiotherapy, C.U. Shah Medical College and Hospital, Surendranagar, Gujarat, India
|Date of Web Publication||7-Feb-2014|
S Gopal Nambi
C.U. Shah Physiotherapy College, Surendranagar - 363 001, Gujarat
Source of Support: None, Conflict of Interest: None
Background: Non-specific chronic low back pain (nCLBP) is prevalent in 80% of low back pain patients and it is multi-dimensional illness. This study aims to test whether short lever or long lever spinal manipulation alleviates clinical symptoms of nCLBP in terms of pain and functional disability. Materials and Methods: Sixty aged 20-60 years with nCLBP were randomly assigned to three groups: the short lever manipulation group received only short lever manipulation (SLM); the long lever manipulation group (LLMG) received only long lever manipulation (LLM); and the control conventional exercises group received conventional exercises (CE). Baseline and after 1 month, 2 month and 6 month follow-up scores were measured with visual analogue scale (VAS) and self-reported functional disability with the Roland-Morris disability questionnaire (RDQ). Results: After treatment, the SLM, LLM, CE all had lower VAS and RDQ scores. Significantly higher reduction and improvement in VAS and RDQ scores were found in the SLM compared to the LLMG. Conclusion: The present study indicates that SLM is more effective than LLM in nCLBP patients in biomechanical perspective.
Keywords: Non-specific chronic low back pain, Roland-Morris disability questionnaire, spinal manipulation, visual analog scale
|How to cite this article:|
Nambi S G, Inbasekaran D, Khuman R, Devi S, Satani K. Clinical effects of short and long lever spinal thrust manipulation in non-specific chronic low back pain: A biomechanical perspective. Int J Health Allied Sci 2013;2:230-6
|How to cite this URL:|
Nambi S G, Inbasekaran D, Khuman R, Devi S, Satani K. Clinical effects of short and long lever spinal thrust manipulation in non-specific chronic low back pain: A biomechanical perspective. Int J Health Allied Sci [serial online] 2013 [cited 2020 Apr 10];2:230-6. Available from: http://www.ijhas.in/text.asp?2013/2/4/230/126706
| Introduction|| |
Low back pain (LBP) is a huge medical and financial problem in the industrialized world. A specific diagnosis of LBP is only possible in 15% of patients. In the majority of cases, LBP is non-specific low back pain (NSLBP).  80-90% of individuals suffering an acute episode of LBP for up to 3 months.  However, a small proportion of patients (10-20%) develop chronic NSLBP, usually defined as pain persisting for longer than 3 months.  Up to 70% of those who initially improve experience repeated fluctuating pain episodes.  The treatment of these patients represents one of the biggest challenges of modern health-care.
An intervention commonly used in physiotherapy for the individuals with LBP is spinal manipulation. The guide to physical therapist practice identifies manipulation as an intervention appropriate for the care of patients with spinal disorders. Jette and Jette  reported manipulation was utilized in 35% of over 1000 patients with LBP treated by physical therapists, less than many other interventions with no supporting evidence.
Several randomized trials have found manipulation to be more effective than placebo  or other interventions.  A few randomized trials have found manipulation to be more beneficial for a sub-group of patients with more acute and chronic symptoms.  However other studies have not shown the benefits of different forms of manipulation techniques in biomechanical perspective for non-specific chronic low back pain (nCLBP).
Despite the clinical evidence for the benefits of and the apparent wide usage of spinal manipulation, the biological mechanisms underlying the effects of spinal manipulation are not known. Although this does not negate the clinical effects of spinal manipulation, it hinders acceptance by the wider scientific and health-care communities and hinders rational strategies for improving the delivery of spinal manipulation.
Thus the purpose of the present study is to conduct randomized control trial (RCT) to compare the clinical effects of two different spinal manipulative thrust techniques in patients with nCLBP patients in a biomechanical perspective.
| Materails and Methods|| |
A total of 122 subjects with LBP were recruited from the local clinics and hospitals and 60 subjects were participated in the study after basic screening. A patient flow chart demonstrating patient recruitment, study design and timing of data collection can be seen in [Figure 1].
The study included the patients who meet the following inclusion criteria:
- Chief complaint of pain and/or numbness in the lumbar spine, buttock and/or lower extremity
- Roland-Morris disability score of at least 25%
- Age >18 years and <60 years.
The following exclusion criteria were used for this study:
- Red flags noted in the participant's general medical screening questionnaire (i.e., tumor, metabolic diseases, rheumatoid arthritis, osteoporosis, prolonged history of steroid use, etc.)
- Signs consistent with nerve root compression.
- Prior surgery to the lumbar spine or buttock
- Current pregnancy
- Past medical history of osteoporosis or spinal compression fracture
- Inability to comply with treatment schedule.
All patients met the inclusion/exclusion criteria and participated in the study. Patients who agreed to participate signed the consent document approved by the Institutional Scientific and Ethical Committee. A therapist blinded to group assignment performed all evaluation procedures. After obtaining informed consent, all subjects completed the remainder of the self-report questionnaires and a physical examination. The following self-report questionnaires were completed by the patient at the baseline examination, demographic data, visual analog scale (VAS) and Roland-Morris disability questionnaire (RDQ). Following completion of self-report measures the patient undergone a standardized historical and physical examination. The questionnaires and the physical examination were repeated following completion of 1 st , 2 nd months and at 6-month follow-up.
A computer random number generator was used to establish randomization lists prior to the initiation of the study. An individual not involved with data collection was generated separate randomization lists for each participating site. Once the baseline examination is completed, therapist blinded to the baseline examination opened the randomization envelope indicating the patient's treatment group assignment that corresponds to the patient's unique identification number. Patients received the treatment according to their group assignment.
Due to the nature of this study, it is not possible to blind the patient or the treating therapist to the treatment received. We blinded the examining therapist performing the baseline and outcome assessments. The examining and treating therapists were different individuals and the examining therapist remains blinded to the patient's treatment group assignment at all times. Patients were instructed not to discuss the particular manual therapy technique received with the examining therapist.
Regardless of treatment group, all patients were scheduled for the treatment session within 3 days of the baseline examination. All patients attended 3 therapy sessions in a week. In each treatment group, the treatment session begun with delivery of the randomly assigned manual therapy technique followed by a range of motion (ROM) exercise. The only difference among the three groups was being the type of manual therapy technique used in the treatment sessions.
Short lever manipulation group (SLMG)
This treatment group received short lever manipulation (SLM) technique performed with the patient side-lying. The patient lied with the more painful side up. The therapist stands in front of the patient. The therapist then flex the top leg until there is movement at the selected segment (e.g., L4-L5) interspace and place the patient's foot in the popliteal fossa of the bottom leg. Next the therapist grasps the patient's bottom shoulder and arm and introduces left trunk side bending and right rotation until motion is felt at the L4-L5 inter space. The therapist's right thumb is then placed on the right side of the L4 spinous process and the patient's arms are positioned around the therapist's right arm. Set-up is maintained while the patient is rolled toward the therapist. Finally the therapist's left arm is used to apply a high velocity, low amplitude thrust of the pelvis in an anterior direction [Figure 2].
The side to be manipulated first was the more symptomatic side based on the patient's self-report. If the patient cannot specify a more symptomatic side, the therapist may select either side for manipulation. The therapist selected the spinal level towards which to direct the manipulation based on segmental mobility assessment performed in side-lying or prone. The therapist chose a segment in the lower lumbar region towards which to direct the manipulation because the lower lumbar spine is more frequently the source of symptoms in patients with LBP and recent research suggests greater benefits from manual therapy techniques directed towards the lower lumbar spine.  The therapist will note whether or not a cavitation (i.e., "a pop") was either heard or felt by the therapist or patient after the manipulation is performed. If a cavitation is experienced, the therapist proceeded to instruct the patient in the ROM exercises. If no cavitation is produced, the patient was repositioned and the manipulation was attempted again. If no cavitation is experienced, the therapist attempted to manipulate the opposite side. A maximum of two attempts per side was permitted. If no cavitation is produced the therapist proceeded to instruct the patient in the ROM exercises. Following the manipulation treatment, all patients were instructed to do the ROM exercises.
Long lever manipulation group (LLMG)
The manipulation technique was performed with the patient supine. The therapist stands on the side opposite of that to be manipulated. The patient passively moved into side-bending towards the side to be manipulated. The patient interlocks the fingers behind his or her head. The therapist passively rotated the patient and then delivered a quick thrust to the ASIS in a posterior and inferior direction [Figure 3].  The side to be manipulated was the more symptomatic side based on the patient's self-report. If the patient cannot specify a more symptomatic side, the therapist may select either side for manipulation. After the manipulation was performed, the therapist noted whether or not a cavitation (i.e., l "a pop") was either heard or felt by the therapist or patient. If a cavitation is experienced, the therapist proceeded to instruct the patient to do the ROM exercises. If no cavitation was produced, the patient was repositioned and the manipulation was attempted again. If no cavitation was experienced, the therapist attempted to manipulate the opposite side. A maximum of two attempts per side was permitted. If no cavitation was produced the therapist was proceeded to instruct the patient to do the ROM exercises.
Range of motion exercise
After received the manual therapy intervention, patients in both the groups were instructed to do pelvic tilt ROM exercise. The pelvic tilt exercise was completed immediately after the manipulation. Subjects were asked to lie on their back and bend the hips and knees so that their feet are flat on the surface. Subjects then attempt to flatten their back on the table by slightly "drawing in" their stomach and rotating the hips backwards without holding their breath. The motion was performed in a pain-free range. Subjects were instructed to perform a set of 10 repetitions after manipulation and they were instructed to perform 10 repetitions of the exercise 3-4 times daily until the treatment session.
The Institutional Scientific and Ethical Committee of have granted approval for the study.
Primary outcomes were pain intensity quantified with a 10 cm VAS (0-100 mm) and self-reported pain disability assessed with an Guajarati version of the RDQ (0-24 points), which is a reliable and valid instrument for measuring functional status in patients with LBP. VAS and RDQ scores were measured immediately before the first treatment and subsequently at 1 month, 2 month and 6 months after the treatment.
Data are presented as mean (standard deviation). SPSS software (version 16.0) SPSS Inc, Chicago was used in all statistical analyses. One-way analysis of variance was performed followed by post-hoc Tukey's multiple comparison test (SPSS version-16.0) to determine significant differences in VAS and RDQ scores between groups. Independent t-test was used for comparison of VAS or RDQ scores between two different groups. Statistical significance level was set at P < 0.05.
| Results|| |
Participants were recruited between May 2011 and April 2012. Of the 122 respondents, 60 (50.2%) met the screening criteria for participants. Four (n = 4) participants dropped out from the trial during the treatment due to lack of time (n = 2) and increased pain after manipulation (n = 2). Follow-up measurements and analyses were performed on the remaining 56 participants who completed the study [Figure 1]. There was no significant difference in baseline variables such as age, sex, height, weight, baseline VAS and RDQ scores between groups [Table 1].
Changes in visual analogue scale scores for pain intensity
VAS scores for pain intensity decreased significantly in all treatment groups; however, the exact time course varied [Table 2]. The SLMG showed a significant decrease in VAS at 1 month, 2 month and 6 months of treatment compared to baseline (P < 0.05) and the control group (P = 0.000). SLM was more effective in pain reduction in the 1 st month of treatment than in the 2 nd month (P = 0.00). Long lever manipulation (LLM) significantly decreased the pain intensity after 2 months of treatment and this effect was stable up to the 6 month of follow-up. VAS demonstrated a significant decrease at the 1 st month after treatment compared to baseline and control group (P = 0.000). VAS in the LLMG decreased significantly at 2 month compared to baseline (P < 0.05) and 1 month of treatment (P = 0.00). The VAS scores were significantly lower in the SLMG than those in the LLMG (P = 0.00) and Control group [Graph 1]. [Additional file 1]
Changes in RDQ scores for pain disability
While the interventions decreased RDQ scores in all the three groups, the exact time course varied [Table 3]. Baseline values of RDQ scores of SLMG, LLMG and conventional exercises group (CEG) shows no statistical difference (P > 0.05). SLM significantly decreased the RDQ scores after 2 months of treatment compared to baseline (P = 0.00) and 1 st month (P = 0.008) but no difference is found between 2 nd and 6 th month (P = 0.112). LLM also significantly decreased the RDQ scores after 2 months of treatment compared to baseline (P = 0.00) and 1 st month (P = 0.000) but no difference is found between 2 nd and 6 th month (P = 0.117). There were significant decreases in RDQ scores in the SLMG and LLMG groups compared to the CEG group at 1 st (P < 0.05) and 2 nd month (P < 0.05). RDQ scores in the SLMG were also significantly lower than those in the LLMG group and CEG group throughout the study (P = 0.00) [Graph 2]. [Additional file 2]
| Discussion|| |
This RCT aims to test the hypothesis whether patients of nCLBP benefit more through SLM technique than through LLM technique in terms of pain and disability.
Large reviews conclude that there is strong evidence for the effectiveness of manipulation as a treatment for LBP. For instance, manipulation and general exercise therapy improves pain and disability and reduces the number of sick days in patients with nCLBP. Nevertheless, it is not clear what kind of manipulation should be used for achieving maximum benefit.
Spinal manipulation by its very nature is a mechanical input to tissues of the vertebral column. During spinal manipulation, the practitioner delivers a dynamic thrust (impulse) to a specific vertebra. The clinician controls the velocity, magnitude and direction of the impulse.  A cracking or popping sound often, but not necessarily, accompanies the manipulation, because gapping the joint creates fluid cavitation.
The most common form of spinal manipulation used by chiropractors is the short-lever, high-velocity and low amplitude thrust.  The clinician usually delivers the dynamic thrust through a short-lever arm by manually contacting paraspinal tissues overlying the spinous, transverse or mammillary processes of the vertebra being manipulated. Alternatively, the clinician contacts tissues overlying the lamina or articular pillar of the vertebra. To manipulate the pelvis, the iliac spine or the ischial spine is used. 
Spinal manipulation may also be delivered through a long-lever arm. While one hand may contact a specific area over the vertebra being manipulated, the second hand contacts the area of the body distant from the specific contact. Force is developed through this long-lever arm. However, using a short-lever arm applied directly over the vertebra minimizes the force necessary to accomplish the manipulation  by reducing the amount of compliant tissue through which the force must be transmitted.
Several laboratories have studied biomechanical features of short and LLM. Hessell et al.  identified two characteristics common to the delivery of a short lever spinal manipulation: (1) A preload force followed by (2) a larger impulse force. Preload load forces ranged from 20 to 180 N and peak forces ranged from 220 to 550 N. Often the preload was approximately 25% of impulse load. The duration of the high-velocity impulse ranged from 200 to 420 ms, but it is vice-versa in LLM. 
A complete understanding of the biomechanics of spinal manipulation requires knowing the manner in which manipulative loads are transmitted to a specific vertebra. Experimentally, this is substantially more difficult and more complex compared with measuring applied loads. Transmitted loads may be different from applied loads because of the effects of patient positioning and the contributions from inertial loads, loading moments and the active and passive properties of the intervening connective and muscle tissues.
Triano and Schultz calculated peak transmitted loads at a lumbar segment by measuring loads transmitted to a force plate placed under the subject. Peak forces transmitted to a lumbar segment during a SLM tended to be higher than peak forces applied during a LLM measured by Herzog et al.  Transmitted impulse durations were similar to applied impulse durations measured by Herzog et al.
In addition to applied and transmitted loads, the relative displacement or movement between contiguous vertebrae during a spinal manipulation has been studied. Nathan and Keller  measured inter vertebral lumbar motion using pins inserted into lumbar spinous processes. Manipulations were delivered using a mechanical adjusting device.  Impulses delivered to the L2 spinous produced 1.62 mm ± 1.06 mm peak axial displacement (in the longitudinal plane), 0.48 ± 0.1 mm shear displacement (in the transverse plane) and 0.89° ± 0.49° of rotation between L3 and L4. 
Numerous theories have been proposed to explain the effects of spinal manipulation. A thread common to many of these theories is that changes in the normal anatomical, physiological or biomechanical dynamics of contiguous vertebrae can adversely affect function of the nervous system.  The mechanical force introduced into the vertebral column during a spinal manipulation may directly alter segmental biomechanics by releasing trapped meniscoids, releasing adhesions or by reducing distortion of the annulus fibrosus. 
Biomechanical changes caused by the manipulation are thought to have physiological consequences by means of their effects on the inflow of sensory information to the central nervous system  By releasing trapped meniscoids, discal material or segmental adhesions, or by normalizing a buckled segment, the mechanical input may ultimately reduce nociceptive input from receptive nerve endings in innervated paraspinal tissues. This would be consistent with the observation that spinal manipulation is not painful when administered correctly. In addition, the mechanical thrust could either stimulate or silence non nociceptive, mechano sensitive receptive nerve endings in paraspinal tissues, including skin, muscle, tendons, ligaments, facet joints and inter vertebral disc. 
A biomechanical alteration between vertebral segments hypothetically produces a biomechanical overload the effects of which may alter the signaling properties of mechanically or chemically sensitive neurons in paraspinal tissues. These changes in sensory input are thought to modify neural integration either by directly affecting reflex activity and/or by affecting central neural integration within motor, nociceptive and possibly autonomic neuronal pools.
Either of these changes in sensory input may elicit changes in efferent somatomotor and visceromotor activity. Pain, discomfort, altered muscle function or altered visceromotor activities comprise the signs or symptoms that might cause patients to seek spinal manipulation. Spinal manipulation, then, theoretically alters the inflow of sensory signals from paraspinal tissues in a manner that improves physiological function. This explanation comprises one of the most rational neuro physiological bases for the mechanisms underlying the effects of spinal manipulation.
This study has several limitations. The treating physiotherapist or subjects cannot be blinded, however because there is no accepted standard therapy, it is not truly known which therapy is better. With a small sample size, the results would have to be interpreted with caution. There are several aspects of the study which influence the external validity. The application of the technique within the study relies on the skills of the treating physiotherapist.
| Conclusion|| |
The present study indicates that SLM is more effective than LLM in nCLBP patients in biomechanical perspective.
| Acknowledgment|| |
All gratitude goes to the management and the patients who participated in the study.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3]