Disc prolapse: evidence of reversal with repeated extension

Porcine Functional Spine Unit in orthopedic research, a systematic scoping review of the methodology

Purpose

The aim of this study was to conduct a systematic scoping review of previous in vitro spine studies that used pig functional spinal units (FSU) as a model to gain an understanding of how different experimental methods are presented in the literature. Research guidelines are often used to achieve high quality in methods, results, and reports, but no research guidelines are available regarding in vitro biomechanical spinal studies.

Methods

A systematic scoping review approach and protocol was used for the study with a systematic search in several data bases combined with an extra author search. The articles were examined in multiple stages by two different authors in a blinded manner. Data was extracted from the included articles and inserted into a previously crafted matrix with multiple variables. The data was analyzed to evaluate study methods and quality and included 70 studies.

Results

The results display that there is a lack of consensus regarding how the material, methods and results are presented. Load type, duration and magnitude were heterogeneous among the studies, but sixty-seven studies (96%) did include compressive load or tension in the testing protocol.

Conclusions

This study concludes that an improvement of reported data in the present field of research is needed. A protocol, modified from the ARRIVE guidelines, regarding enhanced report-structure, that would enable comparison between studies and improve the method quality is presented in the current study. There is also a clear need for a validated quality-assessment template for experimental animal studies.

Relationship between degree of separation of endplate cartilage and severity of intervertebral disc herniation

Degeneration of intervertebral disc and fissures in the anulus was caused by compression and distraction, which lead to nucleus pulposus herniation. However, controversy remains regarding the exact mechanism behind disc herniation. The aim of this study is to analyze histologically the differences between the three types of disc herniations in an attempt to infer the underlying mechanism. Disc samples extracted from 49 patients who underwent discectomy of the lumbar region were studied by histological analysis. The severity of disc herniation was classified as bulging, protrusion, extrusion, or sequestration based on preoperative magnetic resonance imaging measurements. For comparative analysis of sequestration characteristics, 49 patients were classified into either the sequestration or the non-sequestration group (i.e., protrusion and extrusion) according to disc herniation type. Forty of the 49 patients had cartilage present in their disc samples upon histological analysis. The endplate cartilage-containing samples included two of four (50%) protruded disc patients, 22 of 29 (75.9%) extruded disc patients, and 16 of 16 (100%) sequestrated disc patients and had statistical significance (p = 0.019). There were no significant differences in age, sex, body mass index, length of hospital stays, injection history, surgical methods, and Visual Analog Scale between the sequestration and non-sequestration group (all p > 0.05). Separation of endplate cartilage increased with the severity of disc herniation. Therefore, the mechanism of disc herniation should consider the connection with endplate cartilage as an initiating link in the mechanical failure of intervertebral discs.

The acute response of the nucleus pulposus of the cervical intervertebral disc to three supine postures in an asymptomatic population

BACKGROUND

The dynamic disc model refers to the ability of a spinal disc's position to be manipulated by body postures and movements. Research on lumbar discs has indicated movement of the anterior and posterior disc that correlates with posture of the spine. The aim of this study was to assess whether, despite its structural differences, the cervical disc responds to flexed and extended postures in a similar fashion to the lumbar disc.

METHOD

A repeated measures study. Twenty five asymptomatic participants (age: 33.7 ± 9.1 years) volunteered. Scans were performed in supine using an Esaote 0.2T magnetic resonance imaging scanner. Participants lay with their cervical spine initially placed in neutral, followed by flexion and finally extension. The position of the posterior disc nucleus pulposus at C5-6 and C6-7 was measured against a vertical line connecting the posterior vertebral bodies above and below each disc.

RESULTS

Changes in cervical spine position were associated with significant changes in posterior disc nucleus pulposus position at both C5-6 and C6-7 (p < 0.01 for both). Post hoc testing showed a significant difference in posterior disc nucleus pulposus position at C5-6 between flexion and extension (p = 0.02). There was similarly a significant change at C6-7 between neutral and flexion (p = 0.001), and between flexion and extension (p = 0.02).

CONCLUSIONS

These results indicate that the cervical posterior nucleus pulposus is affected by spinal loading, consistent with the concept of the dynamic disc model.

A Dynamic Magnetic Resonance Imaging Study of Changes in Severity of Cervical Spinal Stenosis in Flexion and Extension

Objective

To evaluate changes in the severity of cervical spinal stenosis (CSS) in flexion and extension and determine whether the rate of change with motion varied with severity.

Methods

The study included 92 symptomatic patients with a mean age of 57.80±10.41, who underwent cervical spine dynamic magnetic resonance imaging. The severity of stenosis was evaluated using a semi-quantitative CSS score, ranging from 0 (no spinal stenosis) to 18 (severe stenosis). Radiological evaluation included flexion, neutral, and extension measurements, as determined by the C2–C7 Cobb angle. The severity of stenosis was represented by the total CSS score. The total CSS score in flexion, neutral, and extension positions was compared using repeated measures one-way analysis of variance. The change rate of stenosis per angle motion (CRSPAM) was defined as change in total CSS score divided by change in Cobb angle. The correlation of CRSPAM with severity of stenosis, represented by total CSS score in neutral position, was evaluated using Pearson correlation analysis.

Results

The total CSS score was significantly higher in extension (6.04±2.68) than in neutral position (5.25±2.47) (p<0.001), and significantly higher in neutral than in flexion position (4.40±2.45) (p<0.001). The CRSPAM was significantly and positively correlated with total CSS score in neutral position in the flexion-extension range (r=0.22, p=0.04) and flexion-neutral range (r=0.27, p=0.01).

Conclusion

In symptomatic CSS patients, the radiological severity of stenosis increases with extension and decreases with flexion. In patients with CSS, the rate of variation in spinal stenosis increases with increased severity.

Does the performance of five back-associated exercises relate to the presence of low back pain? A cross-sectional observational investigation in regional Australian council workers

OBJECTIVES

Investigate the relationships between the ability/inability to perform five physical test exercises and the presence or absence of low back pain (LBP).

SETTING

Regional Australian council training facility.

PARTICIPANTS

Consecutive participants recruited during 39 back education classes (8-26 participants per class) for workers in general office/administration, parks/gardens maintenance, roads maintenance, library, child care and management. Total sample (n=539) was reduced through non-consent and insufficient demographic data to n=422. Age 38.6±15.3 years, range 18-64 years, 67.1% male.

METHODS

Cross-sectional, exploratory, observational investigation. LBP presence was ascertained from a three-response option questionnaire: 0=none/rarely (no) 1=sometimes (some), 2=mostly/always (most). Statistical correlation was performed with the number of the five test exercises the individual successfully performed: (1) extension in lying: 3 s; (2) 'toilet squat'; feet flat, feet touched: 3 s; (3) full squat then stand up: 5 times; (4) supine sit-up, knees flexed: 10 times; and (5) leg extension, supine bilateral: 10 times.

INTERVENTIONS

Nil.

RESULTS

For the group 'no-some', 94.3% completed 4-5 test exercises, while for group 'With', 95.7% completed 0-1 test exercises. The relationship between LBP presence and number of exercises performed was highly significant (χ²₍₁₀₎=300.61, p<0.001). Furthermore, multinomial logistic regression predicting LBP (0=no, 1=some, 2=most) from the number of exercises completed, substantially improved the model fit (initial-2LL=348.246, final-2LL=73.620, χ²₍₂₎=274.626, p<0.001). As the number of exercises performed increased, the odds of reporting 'some LBP' or 'most LBP' dropped substantially (ORs of 0.34 and 0.17, respectively).

CONCLUSION

The ability to complete/not complete five test exercises correlated statistically and significantly with a higher LBP absence/presence in a general working population. Training individuals to complete such exercises could facilitate reductions in LBP incidence; however, causality cannot be inferred. Randomised trials are recommended to establish the potential efficacy of exercise-based approaches, considering these five selected exercises, for predicting and managing LBP.

Lumbar extension traction alleviates symptoms and facilitates healing of disc herniation/sequestration in 6-weeks, following failed treatment from three previous chiropractors: a CBP® case report with an 8 year follow-up

[Purpose] To present the outcome of a patient, having sciatica and MRI-verified disc herniation/sequestration who underwent Chiropractic BioPhysics^® (CBP^®) protocol designed to improve the lumbar lordosis. [Subject and Methods] A 56-year-old male suffered from chronic low back pain and recent sciatica due to lumbar disc herniation despite being under continuous care from three previous chiropractors. Radiographic analysis revealed a lumbar hypolordosis and MRI confirmed disc herniation and sequestration at L4–L5. Generalized decreased lumbar range of motion and multiple positive orthopedic and neurologic tests were present. [Results] After 26 treatments of CBP lumbar extension traction over 9-weeks a total reduction of the disc herniation and sequestration occurred with concomitant improvement in neurologic symptoms. Continuing maintenance treatments, an 8 year follow-up shows no relapse of condition and patient remained in good health. [Conclusion] A patient with lumbar disc herniation/sequestration was successfully treated with CBP technique procedures including lumbar extension traction that achieved a significant healing of herniation and significant reduction in symptoms not obtained following traditional chiropractic procedures alone. The quick reduction in lumbar disc herniation would appear to be related to a segmental disc unloading force produced during extension traction procedures for increasing the lumbar curvature.

Disc height loss and restoration via injectable hydrogel influences adjacent segment mechanics in-vitro

BACKGROUND

Height loss can have a profound influence on the local mechanical environment of the disc. While disc height loss is incorporated into scales of degeneration, its direct influence on spine kinematics is unclear. Further, there is a need for minimally invasive techniques to restore disc height; injectable hydrogels are a potential solution. Tandem investigation of disc height loss and subsequent restoration will enhance understanding of spine dysfunction and aberrant movement.

METHODS

Twenty porcine spine specimens with two functional segments were tested in repeated flexion and extension. Relative angular displacement of each segment was measured with full specimen disc height, disc height loss in one of the segments (superior or inferior), and disc height restoration via hydrogel injection.

FINDINGS

Disc height loss decreased the range of motion at the affected segment and increased the range of motion at the adjacent segment. Relative angular displacement decreased at the affected segment by 13.8% (SD=5.3%) and 4.5% (SD=2.1%) for specimens with height loss in the superior and inferior discs respectively. Hydrogel injection was able to restore segmental kinematics to the pre-injury state, with 12.7% (SD=5.5%) and 6.4% (SD=4.2%) of motion regained at the affected segment for superior and inferior disc height loss specimens respectively.

INTERPRETATION

Acute disc height loss reduces motion at an affected segment, while increasing motion at an adjacent segment in-vitro; relative motion appears to be governed by local stiffness. Injectable hydrogels show promise in their ability to restore kinematics to segments with disc height loss.

Male spine motion during coitus: implications for the low back pain patient

STUDY DESIGN

Repeated measures design.

OBJECTIVE

To describe male spine movement and posture characteristics during coitus and compare these characteristics across 5 common coital positions.

SUMMARY OF BACKGROUND DATA

Exacerbation of pain during coitus due to coital movements and positions is a prevalent issue reported by low back pain patients. A biomechanical analysis of spine movements and postures during coitus has never been conducted.

METHODS

Ten healthy males and females engaged in coitus in the following preselected positions and variations: QUADRUPED, MISSIONARY, and SIDELYING. An optoelectronic motion capture system was used to measure 3-dimensional lumbar spine angles that were normalized to upright standing. To determine whether each coital position had distinct spine kinematic profiles, separate univariate general linear models, followed by Tukey's honestly significant difference post hoc analysis were used. The presentation of coital positions was randomized.

RESULTS

Both variations of QUADRUPED, mQUAD1 and mQUAD2, were found to have a significantly higher cycle speed than mSIDE (P = 0.043 and P = 0.034, respectively), mMISS1 (P = 0.003 and P = 0.002, respectively), and mMISS2 (P = 0.001 and P < 0.001, respectively). Male lumbar spine movement varied depending on the coital position; however, across all positions, the majority of the range of motion used was in flexion. Based on range of motion, the least-to-most recommended positions for a male flexion-intolerant patient are mSIDE, mMISS2, mQUAD2, mMISS1, and mQUAD1.

CONCLUSION

Initial recommendations-which include specific coital positions to avoid, movement strategies, and role of the partner-were developed for male patients whose low back pain is exacerbated by specific motions and postures.

LEVEL OF EVIDENCE

N/A.

The probability of spontaneous regression of lumbar herniated disc: a systematic review

OBJECTIVE

To determine the probability of spontaneous disc regression among each type of lumbar herniated disc, using a systematic review.

DATA SOURCES

Medline, Cochrane Library, CINAHL, and Web of Science were searched using key words for relevant original articles published before March 2014. Articles were limited to those published in English and human studies.

REVIEW METHODS

Articles had to: (1) include patients with lumbar disc herniation treated conservatively; (2) have at least two imaging evaluations of the lumbar spine; and (3) exclude patients with prior lumbar surgery, spinal infections, tumors, spondylolisthesis, or spinal stenosis. Two reviewers independently extracted study details and findings. Thirty-one studies met the inclusion criteria. Furthermore, if the classification of herniation matched the recommended classification of the combined Task Forces, the data were used for combined analysis of the probability of disc regression of each type. Nine studies were applicable for probability calculation.

RESULTS

The rate of spontaneous regression was found to be 96% for disc sequestration, 70% for disc extrusion, 41% for disc protrusion, and 13% for disc bulging. The rate of complete resolution of disc herniation was 43% for sequestrated discs and 15% for extruded discs.

CONCLUSIONS

Spontaneous regression of herniated disc tissue can occur, and can completely resolve after conservative treatment. Patients with disc extrusion and sequestration had a significantly higher possibility of having spontaneous regression than did those with bulging or protruding discs. Disc sequestration had a significantly higher rate of complete regression than did disc extrusion.

Extent of nucleus pulposus migration in the annulus of porcine intervertebral discs exposed to cyclic flexion only versus cyclic flexion and extension

BACKGROUND

Repeated flexion of an intervertebral disc has been identified as a mechanism to produce posterior herniations. Repeated extension under certain conditions has also been shown to cause the nucleus of partially herniated discs to reverse and migrate anteriorly. While research shows that the nucleus pulposus migrates anteriorly in extension and infiltrates the annulus posteriorly in flexion, it is not known if a cycle of flexion followed by a cycle of extension produces more or less annular damage compared to pure flexion alone.

METHODS

Two groups of porcine spinal motion segments were exposed to either repeated flexion with extension or just repeated flexion. Digitized photographs of dissected specimens enhanced with a radio-opaque blue dye enabled the quantification of the area of annulus infiltrated with nucleus pulposus.

FINDINGS

Specimens exposed to both flexion and extension showed significantly more annular damage and axial creep compared to those exposed to flexion alone.

INTERPRETATION

It would appear that while flexion alone can still cause nucleus pulposus to track through the annulus of an intervertebral disc, the effects are compounded when it is followed by a subsequent cycle of extension. Thus, movements which require both repetitive flexion and extension, have the potential to produce more annular damage than those which require merely flexion.

Safe physiotherapy interventions in large cervical disc herniations

A 34-year-old woman was seen in a physiotherapy department with signs and symptoms of cervical radiculopathy. Loss of cervical lordosis and a large paracentral to intraforaminal disc prolapse (8&emsp14;mm) at C5-C6 level was reported on MRI. She was taking diclofenac sodium, tramadol HCl, diazepam and pregabalin for the preceding 2&emsp14;months and no significant improvement, except temporary relief, was reported. She was referred to physiotherapy while awaiting a surgical opinion from a neurosurgeon. In physiotherapy she was treated with mobilisation of the upper thoracic spine from C7 to T6 level. A cervical extension exercise was performed with prior voluntary extension of the thoracic spine and elevated shoulders. She was advised to continue the same at home. General posture advice was given. Signs and symptoms resolved within the following four sessions of treatment over 3&emsp14;weeks. Surgical intervention was subsequently deemed unnecessary.

Nucleus pulposus deformation in response to lumbar spine lateral flexion: an in vivo MRI investigation

Whilst there are numerous studies examining aspects of sagittal plane motion in the lumbar spine, few consider coronal plane range of motion and there are no in vivo reports of nucleus pulposus (NP) displacement in lateral flexion. This study quantified in vivo NP deformation in response to side flexion in healthy volunteers. Concomitant lateral flexion and axial rotation range were also examined to evaluate the direction and extent of NP deformation. Axial T2- and coronal T1-weighted magnetic resonance images (MRI) were obtained from 21 subjects (mean age, 24.8 years) from L1 to S1 in the neutral and left laterally flexed position. Images were evaluated for intersegmental ranges of lateral flexion and axial rotation. A novel methodology derived linear pixel samples across the width of the disc from T2 images, from which the magnitude and direction of displacement of the NP was determined. This profiling technique represented the relative hydration pattern within the disc. The NP was displaced away from the direction of lateral flexion in 95/105 discs (p < 0.001). The extent of NP displacement was associated strongly with lateral flexion at L2-3 (p < 0.01). The greatest range of lateral flexion occurred at L2-3, L3-4 and L4-5. Small intersegmental ranges of axial rotation occurred at all levels, but were not associated with NP displacement. The direction of NP deformation was highly predictable in laterally flexed healthy lumbar spines; however, the magnitude of displacement was not consistent with the degree of intersegmental lateral flexion or rotation.

Muscle activation during four Pilates core stability exercises in quadruped position

Queiroz BC, Cagliari MF, Amorim CF, Sacco IC. Muscle activation during four Pilates core stability exercises in quadruped position.

OBJECTIVE

To compare the activity of stabilizing trunk and hip muscles in 4 variations of Pilates stabilizing exercises in the quadruped position.

DESIGN

Repeated-measures descriptive study.

SETTING

A biomechanics laboratory at a university school of medicine.

PARTICIPANTS

Healthy subjects (N=19; mean age +/- SD, 31+/-5y; mean weight +/- SD, 60+/-11kg; mean height +/- SD, 166+/-9cm) experienced in Pilates routines.

INTERVENTIONS

Surface electromyographic signals of iliocostalis, multifidus, gluteus maximus, rectus abdominis, and external and internal oblique muscles were recorded in 4 knee stretch exercises: retroverted pelvis with flexed trunk; anteverted pelvis with extended trunk; neutral pelvis with inclined trunk; and neutral pelvis with trunk parallel to the ground.

MAIN OUTCOME MEASURES

Root mean square values of each muscle and exercise in both phases of hip extension and flexion, normalized by the maximal voluntary isometric contraction.

RESULTS

The retroverted pelvis with flexed trunk position led to significantly increased external oblique and gluteus maximus muscle activation. The anteverted pelvis with trunk extension significantly increased multifidus muscle activity. The neutral pelvis position led to significantly lower activity of all muscles. Rectus abdominis muscle activation to maintain body posture was similar in all exercises and was not influenced by position of the pelvis and trunk.

CONCLUSIONS

Variations in the pelvic and trunk positions in the knee stretch exercises change the activation pattern of the multifidus, gluteus maximus, rectus abdominis, and oblique muscles. The lower level of activation of the rectus abdominis muscle suggests that pelvic stability is maintained in the 4 exercise positions.

Using a pneumatic support to correct sitting posture for prolonged periods: a study using airline seats

Prolonged sitting with spine flexion has been linked to low back disorders. A variety of mechanisms account for this based on biomechanical and neurological variables. Airline seats typically cause pronounced lumbar flexion due to their hollowed seat back design. A pneumatic support, placed between the seat back and the lumbar spine, was tested to see if lumbar flexion was reduced. Results showed that when the seats were positioned in the upright position, 15 of 20 participants experienced reduced lumbar flexion (by 15 degrees on average) with the support. The study was repeated on the five non-responders with the seatback set in the reclined position. This resulted in another four experiencing less lumbar flexion. Since seated flexion is associated with disc stress, reducing flexion with the support reduced lumbar stress. Spine flexion that results from prolonged sitting is associated with disc stress and pain. The pneumatic support tested here reduced spine flexion. While it is not known why airline seats are designed with no lumbar support, which causes excessive lumbar flexion while seated, the pneumatic support corrected this deficit. Reclining the seatback enhanced this effect.