Effect of sciatic nerve neurodynamic sustained natural apophyseal glides on individuals with pelvic crossed syndrome: A randomized controlled trial

Sneha Pradeep; Anand Heggannavar; Santosh Metgud

doi:10.4103/ijptr.ijptr_40_19

ORIGINAL ARTICLE

Year : 2020 | Volume : 2 | Issue : 1 | Page : 35-40

Effect of sciatic nerve neurodynamic sustained natural apophyseal glides on individuals with pelvic crossed syndrome: A randomized controlled trial

Sneha Pradeep, Anand Heggannavar, Santosh Metgud
Department of Orthopaedic Manual Therapy, KAHER, Institute of Physiotherapy, Belagavi, Karnataka, India

Date of Submission	19-Jun-2019
Date of Decision	16-Nov-2019
Date of Acceptance	28-Feb-2020
Date of Web Publication	03-Jul-2020

Correspondence Address:
Dr. Sneha Pradeep
Department of Orthopaedic Manual Therapy, KAHER, Institute of Physiotherapy, Belagavi, Karnataka
India

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijptr.ijptr_40_19

Abstract

Background: Pelvic crossed syndrome (PCS) is a common predisposing factor of low back pain. If left untreated, PCS could result in various spinal and lower-limb pathologies which would hinder an individual's functional abilities and affect their quality of life.
Aims: The study aimed to evaluate the effect of sciatic nerve neurodynamic sustained natural apophyseal glides (SNAGs) along with a stretching-strengthening protocol on individuals with symptomatic PCS.
Settings and Design: This study was conducted in a tertiary care center; this was a randomized controlled trial.
Materials and Methods: Forty-two individuals were randomly allocated to control group (conventional physical therapy) and experimental group (sciatic nerve neurodynamic SNAGs along with conventional physical therapy) using envelope method. The outcome measures – pressure pain threshold, degree of lumbar lordosis, modified Thomas test, finger-to-floor test, and Modified Oswestry Disability Questionnaire (MODQ) were obtained from the participants on day 1 and posttreatment on day 6, respectively. Both the groups received the treatment for 45 min per session for 6 consecutive days.
Statistical Analysis Used: Parametric dependent t-test was applied through R software 3.5.1.
Results: Intragroup analysis revealed statistically significant changes in all outcome measures in both the groups. Statistically significant changes were observed in the intergroup analysis of all the outcome measures (P < 0.0001) in favor of the experimental group except degree of lumbar lordosis (P = 0.78) and MODQ (P = 0.27).
Conclusion: Sciatic nerve neurodynamic SNAGS when given along with conventional therapy resulted in significant and superior improvement as compared to conventional therapy alone in patients with symptomatic PCS in terms of pain sensitivity and flexibility.

Keywords: Low back pain, Manual Therapy, Mobilization, Neurodynamics, Pelvic crossed syndrome, Sciatic nerve

How to cite this article:
Pradeep S, Heggannavar A, Metgud S. Effect of sciatic nerve neurodynamic sustained natural apophyseal glides on individuals with pelvic crossed syndrome: A randomized controlled trial. Indian J Phys Ther Res 2020;2:35-40

How to cite this URL:
Pradeep S, Heggannavar A, Metgud S. Effect of sciatic nerve neurodynamic sustained natural apophyseal glides on individuals with pelvic crossed syndrome: A randomized controlled trial. Indian J Phys Ther Res [serial online] 2020 [cited 2023 Jun 2];2:35-40. Available from: https://www.ijptr.org/text.asp?2020/2/1/35/288862

Introduction

The human movement system comprising the articular, myofascial, neural, and connective tissues of the body is responsible for producing various movements required to perform the activities of daily living. The stability and efficient functioning of this movement system requires the integrated action of the muscle system.^[1],[2]

Movement dysfunction can occur when there is poor integration within the muscle system which can be attributed to an imbalance between the global stabilizers and mobilizers. This imbalance, in turn, leads to altered length and recruitment of these muscles resulting in undue stress over various structures. This stress, if prolonged, can cause pain and pathology to that particular segment of the body, further leading to dysfunction of the local stabilizers. The consequent movement dysfunction can be multisegmental, which can hinder functional movements required to carry out various tasks throughout the day.^[3]

Pelvic crossed syndrome (PCS), also known as lower crossed or distal crossed syndrome termed by Vladimir Janda, is a pattern of muscle imbalance, specifically characterized by patterns of muscular weakness and tightness in specific muscle groups which are morphologically situated opposite to each other between the ventral and dorsal sides of the body. In PCS, tightness is observed in the erector spinae muscle posteriorly, along with the tightness of the iliopsoas and the rectus femoris anteriorly. In addition, there is weakness of the superficial trunk flexors ventrally along with muscle weakness of the gluteus medius and maximus dorsally. The changes occurring due to these muscle imbalances lead to specific postural changes within the body. These changes include increased lumbar lordosis, lateral lumbar shift, anterior pelvic tilt, lateral lower-limb rotation, and knee hyperextension. The specific muscle imbalance seen in PCS gives rise to specific joint dysfunction, particularly in the L4–L5 and L5–S1 segment of the vertebral column along with the hip and the sacroiliac joints. Over time, this causes stress at the L5–S1 segment of the vertebral column leading to pain and irritation in the lower back. In a long-standing case of PCS, further stress can result in tightness of the quadratus lumborum along with weakness of the gluteus maximus and medius.^[4],[5]

Various literatures suggest dysfunction in the muscle system to be an attribute of low back pain. These dysfunctions occur as an altered pattern of muscle recruitment. Individuals report high levels of functional disability with these dysfunctions due to chronic and recurrent low back pain.^[3],[6]

Manual therapy techniques are combined with other physical therapy treatments as a multimodal approach to treat low back pain. Manual therapy techniques usually comprise mobilizations or manipulations at the vertebral column. Neural mobilization is another manual therapy technique which helps to alter the dynamics of the peripheral nerves. This intervention aids in restoring the optimal mechanics of the targeted nerve, thereby improving its mobility. In addition, neurodynamic mobilization also influences the nonneural structures. Neural mobilization is applied for pain management as well.^[7]

There is a vacuum in literature on the combined effects of stretching-strengthening protocol on PCS. Moreover, the effect of neurodynamic sustained natural apophyseal glides (SNAGs) has previously been evaluated on radiating pain, but there is dearth of information regarding its effect on low back pain occurring due to PCS. Hence, this study intends to evaluate the effect of sciatic nerve neurodynamic SNAGs on individuals with symptomatic PCS.

Materials and Methods

Study design and setting

This study was a randomized controlled trial that included a total of 42 individuals recruited from a tertiary care center in Belagavi city, Karnataka, India, during a period of 1 year from April 2018 to March 2019. Ethical clearance was obtained from the Institutional Ethical Committee. The trial was registered with the Clinical Trials Registry-India (CTRI) (CTRI/2018/07/014696). Written informed consent was taken from the individuals before the intervention.

A total of 76 participants were screened at the tertiary care center, of which 34 were included in this randomized controlled trial [Figure 1]. Based on the clinically meaningful differences and variability estimates from relevant literature and consult with expertise in this field, a sample size of 42 participants was calculated at an alpha level of 0.05 with 80% power.^[8] Individuals of both genders between the age groups of 18 and 30 years who had low back pain with diagnosis of PCS were eligible for the study. The participants were also required to have more than Grade 3 strength of abdominal and gluteal muscles as per the Medical Research Council grading. Individuals with any preexisting spinal pathology, congenital abnormality, neurological deficits, recent spinal or lower-limb trauma or surgery, spasm of the trunk or lower-limb muscles, lower-limb radiculopathy, and pregnancy were excluded from the study.

Figure 1: CONSORT chart

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The outcome measures to compare the effect of sciatic nerve neurodynamic SNAGs and conventional physical therapy on pain sensitivity, flexibility of the erector spinae, hamstring, and iliopsoas muscles, degree of lumbar lordosis, and low back pain-related disability were obtained at baseline and after the 6^th day of intervention.

Pain sensitivity

Pain sensitivity (pressure pain threshold) of the erector spinae and quadratus lumborum muscles was assessed using pressure algometer (r = 0.990). The examiner palpated and marked the trigger point following which the pressure algometer was placed vertically to these points slowly at a rate of 1 kg/cm/s approximately. The measurements were expressed in pounds on the algometer. The readings were recorded pre- and postintervention.^[9]

Erector spinae and hamstring flexibility (finger-to-floor test)

The participant was asked to remove footwear and perform trunk flexion while standing on a slightly higher platform with the feet positioned close together. The examiner supervised the test to avoid trick movements such as knee flexion. Another examiner recorded the distance between the tip of the third digit and the platform with a measuring tape. The value was documented in centimeters.^[10]

Iliopsoas muscle flexibility (modified Thomas test)

After obtaining the test position, the angle between the participant's leg and the plinth was obtained using a universal goniometer. The goniometric value was recorded in degree of angulation of the hip to assess the flexibility of the iliopsoas muscles bilaterally.

Degree of lumbar lordosis (flexicurve)

Flexicurve is a valid and reliable tool to assess the degree of lumbar lordosis. The participant was asked to stand erect without shoes. T12 and S2 spinous processes were palpated and marked on the participant. The flexicurve was molded to the shape of the spine from the marked points. The flexicurve was then removed and the inner boundary of the flexicurve was traced on a graph paper, and T12, L4, and S2 were marked and the degree of lumbar lordosis was evaluated.^[11],[12]

Modified Oswestry Disability Questionnaire

The Modified Oswestry Disability Questionnaire (MODQ) is a reliable questionnaire used to assess the extent to which back pain has affected the participant's functional ability. It consists of ten items with six statements in each item. The participant was instructed to answer the questionnaire by marking the most appropriate statement to each item.^[13]

Procedure

All patients with low back pain with PCS were screened for inclusion and exclusion criteria. Participants were informed about the aims and procedure of the study. Written informed consent was obtained from all the individuals willing to participate. After the recruitment of participants, 42 participants were randomly allocated to two groups using envelope method: 21 participants were included under experimental group and 21 under control group. Each participant received one session of 45-min duration per day for 6 days. Baseline demographic details were noted and all outcome measures were assessed and documented on day 1 and day 6.

Control group

The participants in the control group received conventional physical therapy, which included hot moist pack (HMP) for 15 min for the low back in prone position and stretching of tightened structures (back extensors and hip flexors) and strengthening exercises for the weak/inhibited muscles (abdominal muscles and hip extensors). Five sets of stretching with 30-s hold were performed for each muscle. The total duration of one session was 45 min. For strengthening exercises, the participants were instructed to perform ten repetitions for each muscle. The strengthening exercises consisted of curl-ups, side bridge, quadruped hip extension, and side-lying hip abduction.

Experimental group

For participants in the experimental group, sciatic nerve neurodynamic SNAGs were performed along with HMP and conventional physical therapy. For the neurodynamic SNAGS, the participant was seated at the edge of the plinth with the test leg supported by a chair such that the hip was flexed and the knee was completely extended. To hold the limb in the neurodynamic position for the sciatic nerve, pillows were placed on the chair so as to maintain dorsiflexion at the ankle. The contralateral leg was allowed to hang unsupported from the couch. The examiner was standing posterolaterally to the participant to deliver SNAGs centrally to the L5 vertebra. While delivering the SNAGs, the participant was asked to actively flex the trunk and extend back to neutral. This procedure was repeated ten times for each limb in one session following which the conventional treatment was given. Six sessions were performed for each participant allocated to the experimental group].^[14]

Statistical analysis

R 3.5.1 (Microsoft Corporation, 2018) was used for statistical analysis. Mean and standard deviation of baseline demographic data such as gender, age, weight, height, body mass index (BMI) as well as pre- and postintervention values of erector spinae and quadratus lumborum PPT, finger-to-floor distance, modified Thomas test, flexicurve, and MODQ were tabulated. The Shapiro–Wilk test revealed normal distribution of the pre- and postintervention values. The significance level was set to 5%. Parametric dependent t-test was applied for intragroup and intergroup analyses of variables.

Results

Baseline demographic profile was tabulated according to the participants' age, gender, height, weight, and BMI [Table 1]. [Table 2] and [Table 3] describe the comparison of pre- and postintervention values of all outcome measures in the experimental and control groups. [Table 4] describes the between-group comparison of all outcome measures. All outcome measures, namely pressure pain threshold, degree of lumbar lordosis, modified Thomas test, finger-to-floor test, and MODQ, showed a highly significant statistical difference in the within-group analysis for the experimental as well as the control group (P < 0.001). The between-group analysis of pressure pain threshold, modified Thomas test, and finger-to-floor test revealed highly statistical significance (P < 0.001). However, no significant difference was found in the intergroup analysis of flexicurve (P = 0.78) and MODQ (P = 0.27). These values indicate that both the groups are effective in improving outcomes in symptomatic PCS, but the addition of sciatic nerve neurodynamic SNAGs to conventional physical therapy provides additional benefits as compared to physical therapy alone in terms of pain sensitivity and flexibility of the iliopsoas, hamstring, and erector spinae muscles.

Table 1: Demographic characteristics between experimental and control groups

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Table 2: Comparison of pre- and postvalues in the experimental group

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Table 3: Comparison of pre- and postvalues in the control group

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Table 4: Comparison of variables between the experimental and control groups

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Discussion

The results of this present study support the alternative hypothesis, which stated that sciatic nerve neurodynamic SNAGs in addition to conventional physiotherapy will demonstrate a change on the pain sensitivity, flexibility of the iliopsoas, erector spinae, and hamstring muscles, degree of lumbar lordosis, and low back pain-related disability. The between-group analyses suggested that the sciatic nerve neurodynamic SNAGs in addition to conventional physiotherapy proved more beneficial on all the outcome measures except degree of lumbar lordosis and low back pain-related disability, as compared to the conventional physiotherapy (stretching-strengthening protocol) alone.

There are various proposed mechanisms on the beneficial effects of lumbar SNAGs regarding pain sensitivity: first, the application of lumbar SNAGs reduces the capsular tension at the facet joints, thereby correcting any underlying mechanical fault at the facet joints. The second mechanism may be explained through the theory of habituation and extinction. Individuals who usually experience pain during a specific movement may develop fear to perform any activity that involves that particular movement. The application of lumbar SNAGs requires the individual to perform the painful movement in a graded manner with reduced pain. When the patient is repeatedly exposed to this particular movement in a pain-free manner, it causes habituation and extinction of the aversive memory. Third, SNAGs is known to produce similar effects as posteroanterior passive mobilization technique at the lumbar spine. Lumbar mobilization can reduce joint position error and improve joint position sense. Hence, the application of SNAGs can lead to the correction of positional faults and improve muscular function, mobility, and flexibility. In addition, it can also cause a psychological response which can be attributed to the patient's expectation from the treatment and patient–therapist interaction.^[15],[16]

The stretching of the iliopsoas muscle causes a change in the flexibility of the iliopsoas muscle which might have led to reduction in low back pain symptoms following intervention. A study done in 2015 supports the finding of the present study which states that individuals with tightness of the iliopsoas muscles have greater pelvic tilt and lumbar lordosis. The study suggested that iliopsoas stretching and corrective exercises for lumbar lordosis and pelvic inclination should be incorporated into the protocol for the management of low back pain.^[17],[18]

Apart from its neurological effects, sciatic nerve neurodynamic technique is also known to improve hamstring ROM in individuals with limited hamstring flexibility. It is stated in previous literature that sciatic nerve neurodynamic techniques are equally effective as conventional stretching techniques to improve hamstring flexibility. The result of this study corroborates the findings of the present trial where there was an additional improvement in the postintervention finger-to-floor test values in the experimental group. Thus, changes in the flexibility of the muscles may also have played a role in correcting mechanical faults by changing the inclination at the pelvis and thereby the lumbar spine.^[19]

Possible mechanism for the reduction in lumbar lordosis in both the groups could be attributed to the change in flexibility of the iliopsoas, erector spinae, and hamstring muscles and strengthening of the abdominal and gluteal muscles which might have caused a change in lumbar lordosis by breaking the compensatory pattern attained in the lumbopelvic alignment due to weakness and tightness of opposite muscle groups.^{[18],[20],[21]}

Previous studies are in consensus with the results of the present study where low back pain-related function was assessed using the Oswestry Disability Questionnaire. Superficial strengthening exercises for the abdominal and trunk muscles have reported to be beneficial in reducing pain and improving disability. Lower-limb neurodynamic mobilization is also known to cause changes in the volume of intraneural fluid at the nerve root, thereby preventing neural edema, decreasing pain, and improving function. Lumbar SNAGs have also been proven beneficial for functional improvement in individuals with chronic nonspecific low back pain. The improvement in different biomechanical variables related to the cause of low back pain appears to provide an overall functional improvement in individuals with low back pain.^{[17],[22],[23]}

The present study had a few limitations. First, the carryover and long-term effects of the intervention were not analyzed. The strength of the abdominal and gluteal muscles was not assessed since only six sessions of treatment were given, and to have any positive strength gains, minimum of 3 weeks of treatment is required. The assessment of flexibility of the erector spinae muscles could not be isolated due to the unavailability of objective outcome measures for the same.

The isolated effect of sciatic nerve neurodynamic SNAGs may be assessed by comparing the technique to a sham myofascial release application or with other manual therapy techniques such as neural mobilization, lumbar SNAGs, and other techniques of Mulligan's mobilization in individuals with symptomatic PCS. The effect of intervention may be evaluated on properties of the muscle and nerves using more sophisticated tools such as dynamic ultrasonography. An outcome measure should be developed to assess the isolated flexibility of the erector spinae so as to assess the effect of the techniques on the same.

Conclusion

The study concluded that sciatic nerve neurodynamic SNAGs when given as an adjuvant to conventional physical therapy proved to provide significant and faster improvement in participants with symptomatic PCS in terms of pain sensitivity and flexibility of the erector spinae, hamstring, and iliopsoas muscles.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflict of interest.

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