Does the morphology of the iliolumbar ligament affect lumbosacral disc degeneration?

Relationship between first tarsometatarsal ligament morphology and its continuity with the fibularis longus and first tarsometatarsal joint degeneration

This study explored the relationship between the morphological characteristics of the first tarsometatarsal ligaments and fibularis longus (FL) and the severity of articular cartilage degeneration in the first tarsometatarsal joint. Sixty legs from 30 cadavers were examined. The plantar, dorsal, and medial first tarsometatarsal ligaments were classified by fiber bundle number, and their morphological characteristics (fiber bundle length, width, thickness) were measured. The FL was categorized by its continuity with the plantar first tarsometatarsal ligament (PTML): Type A, connection with the PTML only on the first metatarsal; Type B, connection along the entire PTML; and Type C, no connection with the PTML. The severity of articular cartilage degeneration was assessed in four stages. No significant differences in cartilage degeneration among ligament types were found. Negative correlations were observed between the fiber bundle width and thickness of the PTML and the severity of cartilage degeneration. FL was classified as Type A in 68%, Type B in 27%, and Type C in 5% of feet. The fiber bundle thickness of the PTML in Type B was greater than in other types. Our findings suggest that smaller fiber bundle width and thickness in the PTML may be associated with severe cartilage degeneration. The FL had continuity with the PTML in 95% of feet and could enhance the mechanical strength of the PTML in Type B feet.

Levels of 91 circulating inflammatory proteins and risk of lumbar spine and pelvic fractures and peripheral ligament injuries: a two-sample mendelian randomization study

OBJECTIVE

Lumbar spine and pelvic fractures(LPF) are combined with peripheral ligament injuries(PLI), frequently. It has been reported that the site of fracture injury is usually paralleled by the secretion of inflammatory proteins. This study aimed to investigate the causal relationship between 91 circulating inflammatory proteins and LPF and PLI by using a Two-sample Mendelian randomization (MR) analysis.

METHODS

Single nucleotide polymorphisms (SNPs) associated with 91 circulating inflammatory proteins, as exposures were selected from a large genome-wide association study (GWAS). The genetic variant data for LPF and PLI as outcomes from the FinnGen consortium. The inverse-variance-weighted (IVW) method was utilized as the main analysis for exposures and outcomes. In addition, the final results were reinforced by the methods of MR Egger, weighted median, simple mode, and weighted mode. The sensitivity analyses were used to validate the robustness of results and ensure the absence of heterogeneity and horizontal pleiotropy. MR-Steiger was used to assess whether the causal direction was correct to avoid reverse causality.

RESULTS

This study has shown that Beta-nerve growth factor(Beta-NGF) and Interferon gamma(IFN-gamma) are both involved in the occurrence of LPF and PLI, and they are reducing the risk of occurrence(OR:0.800, 95%CI: 0.650-0.983; OR:0.723, 95%CI:0.568-0.920 and OR:0.812, 95%CI:0.703-0.937; OR:0.828, 95%CI:0.700-0.980). Similarly, Axin-1 and Sulfotransferase 1A1 (SULT-1A1) were causally associated with LPF(OR:0.687, 95%CI:0.501-0.942 and OR:1.178,95%CI:1.010-1.373). Furthermore, Interleukin-4(IL-4), Macrophage inflammatory protein 1a(MIP-1a), and STAM binding protein(STAM-BP) were causally associated with PLI(OR:1.236, 95% CI: 1.058-1.443; OR:1.107, 95% CI: 1.008-1.214 and OR:0.759, 95% CI: 0.617-0.933). The influence of heterogeneity and horizontal pleiotropy were further excluded by sensitivity analysis.

CONCLUSION

This study provides new insights into the relationship between circulating inflammatory proteins and LPF and PLI, and may provide new clues for predicting this risk.

Relationship between lumbosacral transitional vertebra and postoperative outcomes of patients with Lenke 5C adolescent idiopathic scoliosis: a minimum 5-year follow-up study

PURPOSE

To assess the incidence of lumbosacral transitional vertebra (LSTV) in Lenke 5C adolescent idiopathic scoliosis (AIS) and evaluate the relationship between postoperative outcomes and LSTV when the lowest instrumented vertebra (LIV) is fixed at L3.

METHODS

The study included 61 patients with Lenke 5C AIS who underwent fusion surgery of L3 as the LIV who were followed-up for a minimum of 5 years. Patients were divided into two groups: LSTV + and LSTV-. Demographic, surgical, and radiographic data, including L4 tilt and thoracolumbar/lumbar (TL/L) Cobb angle, were obtained and analyzed.

RESULTS

LSTV was observed in 15 patients (24.5%). The L4 tilt was not significantly different between the two groups preoperatively (P = 0.54); however, it was significantly greater in the LSTV group postoperatively (2 weeks: LSTV +  = 11.7 ± 3.1, LSTV -  = 8.8 ± 3.2, P = 0.013; 2 years: LSTV +  = 11.5 ± 3.5, LSTV -  = 7.9 ± 4.1, P = 0.006; 5 years: LSTV +  = 9.8 ± 3.1, LSTV -  = 7.3 ± 4.5,  P= 0.042). The postoperative TL/L curve was greater in the LSTV + group, with significant differences at 2 weeks and 2 years postoperatively (preoperative: LSTV +  = 53.5 ± 11.2, LSTV -  = 51.7 ± 10.3,P = 0.675; 2 weeks: LSTV +  = 16.1 ± 5.0, LSTV- = 12.2 ± 6.6, P = 0.027; 2 years: LSTV +  = 21.7 ± 5.9, LSTV -  = 17.6 ± 5.9, P = 0.035; 5 years: LSTV +  = 18.7 ± 5.8, LSTV -  = 17.0 ± 6.1, P = 0.205).

CONCLUSION

The prevalence of LSTV in Lenke 5C AIS patients was 24.5%. Lenke 5C AIS patients with LSTV with the LIV at L3 had a significantly greater postoperative L4 tilt than those without LSTV and retained the TL/L curve.

Anatomy and morphology of iliolumbar ligament

PURPOSE

To address limited amount of available data and contradictory statements in published works 60 Iliolumbar ligaments extracted from 30 cadavers were examined to describe their insertions and morphology.

METHODS

The ligaments were removed during the standard autopsy procedures with a use of an oscillating saw, a chisel and a scalpel. The specimens were photographed before the extraction and measured alongside their anterior margin. Next, they were preserved in formaldehyde, stripped of other soft tissues and then examined, photographed and described.

RESULTS

The mean length of the ligaments was 31.7 mm. 44 specimens were described as single-banded, 13 as double-banded and 3 as other. In 24 cases costal process of L_V has been fixed to the iliac plate by short ligamentous bands. In 38 cases there was a thick fibrous membrane connected to the ligament. No legitimate insertions on L_IV vertebra were observed.

CONCLUSIONS

Typical iliolumbar ligament consists of a single ligamentous band. Most common variability of the ligament consist of two bands. In approximately 40% of cases the costal process of L_V can be additionally stabilized to the iliac plate by short, strong ligamentous bands. In 63% of cases a connection between the iliolumbar ligament and a fibrous membrane placed in the frontal plane, superiorly to the ligament, has been observed. There seems to be no convincing proof of existence of the insertion of the iliolumbar ligament on the L_IV vertebra.

Identifying the relationship between lumbar sacralization and adjacent ligamentous anatomy in patients with Bertolotti syndrome and healthy controls

OBJECTIVE

Bertolotti syndrome is a diagnosis given to patients experiencing low-back pain due to a lumbosacral transitional vertebra (LSTV). LSTVs cause altered biomechanics at the lumbosacral junction, predisposing these patients to degenerative disease. It has been proposed that these patients have additional non-osseous variation such as ligamentous differences in the lumbar spine. The iliolumbar ligament, which attaches from the iliac crest to the transverse process of L4 and L5, plays a significant role in reducing lumbar motion in all six degrees of freedom; therefore, altered ligament anatomy can have a significant impact on stability. The purpose of this study was to examine the iliolumbar ligament complex in patients with Bertolotti syndrome and anatomically normal controls to determine if underdevelopment of the iliolumbar ligament complex is seen in Bertolotti syndrome.

METHODS

This is a retrospective analysis of patients with Bertolotti syndrome and anatomically normal controls who received care at the authors' institution between 2010 and 2020. Axial thickness of the iliolumbar ligament at the L5 vertebral level was assessed via MRI. Results were compared between the defective and normal side within unilaterally affected (Castellvi types IIa and IIIa) Bertolotti syndrome patients, between defective sides in bilaterally affected Bertolotti syndrome patients (Castellvi types IIb, IIIb, and IV), and between the affected side in Bertolotti syndrome patients and the corresponding location in normal controls.

RESULTS

A total of 173 patients were included in the study, 102 with Bertolotti syndrome and 71 controls. Among the Bertolotti patients, 49 had left LSTVs, 29 had right LSTVs, and 24 had bilateral LSTVs. For patients with unilateral defects, defective side ligaments were thinner than ligaments on the normal side (p < 0.05). For bilateral LSTVs, ligament thickness on each side was considered statistically equivalent (p < 0.05) and not significantly different from that in controls.

CONCLUSIONS

Bertolotti syndrome correlates to significant underdevelopment of the iliolumbar ligament corresponding to the side of the LSTV as compared to the ligament on the contralateral side. In patients with bilateral LSTVs, no difference in the iliolumbar ligament compared to that in controls was seen. Developmental changes in the iliolumbar ligament may further exacerbate the altered lumbosacral biomechanics seen in patients with unilateral LSTV, whereas bilateral LSTVs may still allow normal development of the ligament complex. Further research should be done to examine the discrepancies seen in this study.

Patterns of Lumbar Disc Degeneration: Magnetic Resonance Imaging Analysis in Symptomatic Subjects

Study Design

Cross-sectional study.

Purpose

To evaluate lumbar disc degeneration (LDD) on magnetic resonance imaging (MRI) in symptomatic subjects to accumulate baseline data on the pattern of degeneration.

Overview of Literature

LDD plays an important role in the diagnosis and treatment of low-back pain in patients. Few studies have focused on the pattern of LDD to understand how the lumbar spine ages.

Methods

This study included 1,095 patients (mean age, 44.29 years; range, 16-85 years) who underwent upright lumbar MRI. LDD was graded into five categories (I-V). Positive LDD was defined as grade III or greater. The prevalence and pattern of LDD were analyzed, and the correlations between age and total grade of LDD were evaluated.

Results

The average number of LDD levels and the total grade of LDD increased with age. LDD moved cephalad with age. The rate of LDD increased rapidly during the decade before the prevalence of LDD and became >50%. In the single-level LDD group, the levels L5-S1 were the most common levels (60.3%). In the two-level group, L4-L5 and L5-S1 were the most common levels (53.5%). In the three-level group, L3-L4, L4-L5, and L5-S1 were the most common levels (55.7%). In the multilevel LDD group, contiguous multilevel disc degeneration (CMDD) was more common than the skipped level disc degeneration (SLDD). The levels L4-L5 were the most common levels in the CMDD group, and L5-S1 were the most common levels among SLDD.

Conclusions

LDD was found to correlate with age, and the specific patterns and rates of LDD depended on lumbar disc level and age. These LDD pattern data can be used before spinal procedures to predict the probability of natural LDD progression with age.

Is Lumbosacral Transitional Vertebra Associated with Degenerative Lumbar Spinal Stenosis?

The aim of this study was to shed light on the association between lumbosacral transitional vertebra (LSTV) and degenerative lumbar spinal stenosis (DLSS). A cross-sectional retrospective study was performed on 165 individuals that were diagnosed with clinical picture of DLSS (age range: 40-88 years; sex ratio: 80M/85F) and 180 individuals without DLSS related symptoms (age range: 40-99 years; sex ratio: 90M/90F). All participants had undergone high-resolution CT scan for the lumbar region in the same position. We also used the volume rendering method to obtain three-dimensional CT images of the lumbosacral area. Both males and females in the stenosis group manifest greater prevalence of LSTV than their counterparts in the control group (P<0.001). Furthermore, the presence of LSTV increases the likelihood of degenerative spinal stenosis (odds ratio= 3.741, P<0.001). In the control group, LSTV was more common in males, and sacral slope angle of males was significantly greater in LSTV group compared to non-LSTV. This study indicates that LSTV was significantly associated with symptomatic DLSS.

Effect of lumbar stabilization exercise on disc herniation index, sacral angle, and functional improvement in patients with lumbar disc herniation

[Purpose] This study aimed to examine the effects of pelvic movements on the back function of patients with lumbar disc herniation when lumbar stabilization exercise was applied to the patients, suggest an intervention method that can be used in future clinical therapies. [Subjects and Methods] Thirty patients with lumbar disc herniation underwent the intervention 30 minutes per day, three times per week for 4 weeks. Of them, 15 patients were assigned to the balance center stabilization resistance exercise group (experimental group I) and the other 15 were assigned to the three-dimensional stabilization exercise group (experimental group II). Before the intervention, disc herniation index was measured using magnetic resonance imaging, sacral angle was measured using X-ray, and back function was measured using the KODI. Four weeks later, these three factors were re-measured and analyzed. [Results] There was a significant pre- versus post-intervention difference in disc herniation index, sacral angle, and KODI in experimental group I and a significant difference in disc herniation index and KODI in experimental group II, and each group of disc herniation index and sacral angle had a significant difference. In experimental group I, each disc herniation index and sacral angle had a negative correlation. [Conclusion] The lumbar stabilization exercise, which controls balance using pelvic movements, improves mobility and stability of the sacroiliac joint; therefore, it increases pelvic and back movements. These kinds of movements not only improved proprioception sense, they also had positive effects on lumbar disc function recovery.

Lumbosacral Transitional Vertebra: Possible Role in the Pathogenesis of Adolescent Lumbar Disc Herniation

OBJECTIVE

To investigate the role of lumbosacral transitional vertebra (LSTV) in the pathogenesis of adolescent lumbar disc herniation (ALDH) and the association between LSTV type and the herniation level of ALDH.

METHODS

This study was a retrospective case-control analysis of roentgenographic images. All adolescent patients who received surgical treatment for L4/5 or L5/S1 single level lumbar disc herniation in our department from 2010 to 2015 were eligible for the ALDH group. All adolescent patients admitted to our hospital during the same period and who had ever undergone a plain anteroposterior radiologic examination of the abdomen and met the inclusion criteria that ensured the absence of any spinal disorders were selected into the control group. The anteroposterior lumbar or abdomen roentgenograms were collected to identify the LSTV. The incidence of LSTV in the ALDH group and the control group were compared. Among the ALDH group, the association between LSTV type (sacralization or lumbarization) and the herniation level of ALDH were evaluated.

RESULTS

A total of 80 adolescent patients were included in the ALDH group and 92 asymptomatic adolescents were included in the control group. LSTV was found in 24 patients (30%) in ALDH group compared with 7 patients (7.6%) in the control group (P < 0.001; odds ratio, 5.2; 95% confidence interval 2.1, 12.9). Among the adolescent patients with sacralization, the L4/5 disc herniation was significantly more common than L5/S1 (81.3% vs. 18.7%; P = 0.019).

CONCLUSIONS

The LSTV is associated with LDH in adolescents and the sacralization of L5 may contribute to the L4/5 disc herniation in adolescent patients.

Are Transitional Vertebra and Spina Bifida Occulta Related with Lumbar Disc Herniation and Clinical Parameters in Young Patients with Chronic Low Back Pain?

OBJECTIVE

Lumbosacral transitional vertebra (LSTV) and spina bifida occulta (SBO) are widespread within the lumbosacral spine. Their connection to lumbar disc herniation (LDH) and/or lower back pain has been debated in the current literature; however, there is no consensus. The purpose of this study is to evaluate the relationship between the frequency of LSTV and SBO with that of LDH among young patients with chronic lower back pain.

STUDY DESIGN

Cross-sectional.

MATERIALS AND METHODS

A total of 1094 patients with lower back pain, aged between 20 and 40 years, with lower back pain history persisting for longer than 12 weeks were studied. All the patients in the study were evaluated with standard pelvic radiographs and lumbar vertebra magnetic resonance imaging. The severity of pain was measured using the visual analog scale, and the effect of lower back pain on daily life activities was measured using the Oswestry disability index. The patients were separated into two groups: Group 1 consisted of patients without LDH, and Group 2 consisted of patients with LDH. Additionally, these two groups were separated into three subgroups: Non-LSTV-SBO, LSTV, and SBO.

RESULTS

It was determined that LSTV frequency was significantly higher (p=0.004) in the lumbar disc herniation group 2. In addition, the existence of LSTV increased the risk of lower back pain (p<0.001, p<0.001) and disability (p<0.001, p<0.001) in young patients with and without LDH or not. However, the presence of SBO did not increase lower back pain (p=0.251, p=0.200) and disability (p=0.134, p=0.161) in both groups.

CONCLUSION

A relationship was detected between the frequency of LDH and LSTV in young patients with chronic lower back pain between the ages of 20 and 40 years. Also, the presence of LSTV was found to increase the risk of lower back pain and disability.

Musculoskeletal Modeling of the Lumbar Spine to Explore Functional Interactions between Back Muscle Loads and Intervertebral Disk Multiphysics

During daily activities, complex biomechanical interactions influence the biophysical regulation of intervertebral disks (IVDs), and transfers of mechanical loads are largely controlled by the stabilizing action of spine muscles. Muscle and other internal forces cannot be easily measured directly in the lumbar spine. Hence, biomechanical models are important tools for the evaluation of the loads in those tissues involved in low-back disorders. Muscle force estimations in most musculoskeletal models mainly rely, however, on inverse calculations and static optimizations that limit the predictive power of the numerical calculations. In order to contribute to the development of predictive systems, we coupled a predictive muscle model with the passive resistance of the spine tissues, in a L3-S1 musculoskeletal finite element model with osmo-poromechanical IVD descriptions. The model included 46 fascicles of the major back muscles that act on the lower spine. The muscle model interacted with activity-related loads imposed to the osteoligamentous structure, as standing position and night rest were simulated through distributed upper body mass and free IVD swelling, respectively. Calculations led to intradiscal pressure values within ranges of values measured in vivo. Disk swelling led to muscle activation and muscle force distributions that seemed particularly appropriate to counterbalance the anterior body mass effect in standing. Our simulations pointed out a likely existence of a functional balance between stretch-induced muscle activation and IVD multiphysics toward improved mechanical stability of the lumbar spine understanding. This balance suggests that proper night rest contributes to mechanically strengthen the spine during day activity.

Risk Factors For the Development of a Mobile Degenerative Spondylolisthesis at L4-L5

OBJECTIVE

The purpose of this study was to identify factors that may be important in determining whether a degenerative spondylolisthesis at L4-L5 is mobile.

SUMMARY OF BACKGROUND DATA

Degenerative scoliosis is a common condition among middle-aged and elderly adults. Sacropelvic morphology and orientation modulate the geometry of the lumbar spine and, consequently, the mechanical stresses at the lumbo-sacral junction. To date, no in vivo data exist to describe the relationship between these pelvic parameters and their association with a mobile spondylolisthesis.

METHOD

Sixty consecutive patients with a degenerative spondylolisthesis (DS) at L4-L5 with adequate imaging were identified. Patient groups were defined on the basis of whether the DS was mobile (Group A) or nonmobile (Group B) when comparing the upright plain lumbar radiograph to the supine magnetic resonance imaging (MRI). We assessed the grade of slip, lumbar lordosis, pelvic parameters, and facet characteristics (angles, tropism, presents of effusion, degenerative score-cartilage and sclerosis values) as well as disc degenerative score (Pfirrmann) at L4-L5.

RESULTS

There were 40 patients in Group A and 20 in Group B. No significant differences were found between groups for pelvic incidence (p = .409), pelvic tilt (p = .476), sacral slope (p = .785), lumbar lordosis (p = .695), degree of facet tropism (p = .38), and magnitude of the facet effusions (p = .01). Facet angle differences between groups approached significance (p = .058). Significant differences between groups were found in cartilage degenerative score (p = .01), facet sclerosis grade (p = .01), and disc degenerative score (p < .0001). In Group A, 10 of 40 (25%) reduced fully and were not apparent on the supine MRI.

CONCLUSIONS

Sagittal pelvic parameters do not play a significant role in differentiating between mobile and nonmobile DS at L4-L5. However, DS does appear to be associated with more sagittally orientated facets, higher Pfirrmann grade, and higher facet cartilage and sclerosis degenerative scores.

Minimally invasive tubular resection of the anomalous transverse process in patients with Bertolotti's syndrome: presented at the 2013 Joint Spine Section Meeting: clinical article

OBJECT

Bertolotti's syndrome consists of low-back pain caused by lumbosacral transitional vertebrae (LSTVs) and LSTV-associated biomechanical spinal changes. There is a lack of consensus regarding the cause, clinical significance, and treatment of this condition. The authors aim to characterize the clinical presentation of patients with Bertolotti's syndrome and describe a minimally invasive surgical treatment for this condition.

METHODS

Seven patients who underwent minimally invasive paramedian tubular-based resection of the LSTV for Bertolotti's syndrome were identified over the course of 5 years. Diagnosis was based on patient history of chronic low-back pain, radiographic findings of LSTV, and pain relief on trigger-site injection with steroid and/or anesthetics. Electronic medical records were reviewed to identify demographics, operative data, and outcomes.

RESULTS

All patients presented with severe, chronic low-back pain lasting an average of 8 years that was resistant to nonoperative care. At presentation, 6 (86%) of 7 patients experienced radicular pain that was ipsilateral to the LSTV. Radiographic evidence showed a presence of LSTV in all patients on the left (43%), right (29%), or bilaterally (29%). Degenerative disc changes at the L4-5 level immediately above the anomalous LSTV were observed in 6 of 7 (86%) patients; these changes were not seen at the level below the LSTV. Following pseudo-joint injection, all patients experienced temporary relief of their symptoms. All patients underwent a minimally invasive, paramedian tubular-based approach for resection of the LSTV. Three (43%) of 7 patients reported complete resolution of low-back pain, 2 (29%) of 7 patients had reduced low-back pain, and 2 patients (29%) experienced initial relief but return of low-back pain at 1 and 4 years postoperatively. Three (50%) of the 6 patients with radicular pain had complete relief of this symptom. The median follow-up time was 12 months. No intraoperative complication was reported. Two (29%) of 7 patients developed postoperative complications including one with a wound hematoma and another with new L-5 radiculopathy that resolved 2 years after surgery.

CONCLUSIONS

Diagnosis of Bertolotti's syndrome should be considered with adequate patient history, imaging studies, and diagnostic injections. A minimally invasive surgical approach for resection of the LSTV is presented here for symptomatic treatment of select patients with Bertolotti's syndrome whose conditions are refractory to conventional therapy and who have pain that can be attributed to the LSTV. Several short-term complications were noted with this procedure, but overall this procedure is effective for treating symptoms related to Bertolotti's syndrome.

Lumbosacral transitional vertebrae: classification, imaging findings, and clinical relevance

SUMMARY

LSTVs are common within the spine, and their association with low back pain has been debated in the literature for nearly a century. LSTVs include sacralization of the lowest lumbar vertebral body and lumbarization of the uppermost sacral segment. These vertebral bodies demonstrate varying morphology, ranging from broadened transverse processes to complete fusion. Low back pain associated with an LSTV may arise from the level above the transition, the contralateral facet when unilateral, and/or the anomalous articulation when present. Although this association is still somewhat controversial, beyond dispute is the importance of identifying an LSTV in patients in whom a surgical or interventional procedure is planned. This is essential to avoid an intervention or surgery at an incorrect level. In this article, each of these issues will be addressed with attention to identifying and correctly numbering LSTVs as well as detecting imaging findings related to the genesis of low back pain.

Disc height and lumbar index as independent predictors of degenerative spondylolisthesis in middle-aged women with low back pain

STUDY DESIGN

A age- and sex-matched case-control radiographic study.

OBJECTIVE

To identify the predisposing factors of degenerative spondylolisthesis (DS).

SUMMARY OF BACKGROUND DATA

None of the radiologic methods for predicting the development of DS are very reliable or readily accessible. The methods commonly used are computed tomography or magnetic resonance imaging.

METHODS

Data were gathered retrospectively on middle-aged women with degenerative lumbar spondylolisthesis.

RESULTS

The most common slipped vertebra was L4 (63.64%) and the second was L5 (13.64%). Most parameters, including the disc height, body height, and angle measurements, for the case group tended to be lower than the control group, whereas the transverse process were larger than control group. The differences in disc height, lumbar index (LI), sacral inclination angle (SIA), sacral horizontal angle (SHA), and transverse process between the 2 groups were statistically significant (P < 0.05). Multivariate logistic regression analysis confirmed that anterior inferior disc height (DHIA) and LI were independent variables of predisposing factor to DS and both could explain a 50% variation of DS. Further analysis of the different levels of spondylolisthesis (L4 on L5 vs. L5 on S1 DS) revealed that there was a significant difference in the width of L5 transverse process in L4 on L5 spondylolisthesis (P = 0.03) but insignificant on disc height (P = 0.86).

CONCLUSION

There are 2 independent predictors of DS, decreased anterior disc height and increased lumbar index. The iliolumbar ligament also contributes to the stability of lumbosacral junction, especially in L5 on S1 DS.

Basic Science Research Related to Chiropractic Spinal Adjusting: The State of the Art and Recommendations Revisited

OBJECTIVE

The objectives of this white paper are to review and summarize the basic science literature relevant to spinal fixation (subluxation) and spinal adjusting procedures and to make specific recommendations for future research.

METHODS

PubMed, CINAHL, ICL, OSTMED, and MANTIS databases were searched by a multidisciplinary team for reports of basic science research (since 1995) related to spinal fixation (subluxation) and spinal adjusting (spinal manipulation). In addition, hand searches of the reference sections of studies judged to be important by the authors were also obtained. Each author used key words they determined to be most important to their field in designing their individual search strategy. Both animal and human studies were included in the literature searches, summaries, and recommendations for future research produced in this project.

DISCUSSION

The following topic areas were identified: anatomy, biomechanics, somatic nervous system, animal models, immune system, and human studies related to the autonomic nervous system. A relevant summary of each topic area and specific recommendations for future research in each area were the primary objectives of this project.

CONCLUSIONS

The summaries of the literature for the 6 topic sections (anatomy, biomechanics, somatic nervous system, animal models, immune system, and human studies related to the autonomic nervous system) indicated that a significant body of basic science research evaluating chiropractic spinal adjusting has been completed and published since the 1997 basic science white paper. Much more basic science research in these fields needs to be accomplished, and the recommendations at the end of each topic section should help researchers, funding agencies, and other decision makers develop specific research priorities.

Provocative sacroiliac joint maneuvers and sacroiliac joint block are unreliable for diagnosing sacroiliac joint pain

Mapping studies of pain elicited by injections into the sacroiliac joints (SIJs) suggest that sacroiliac joint syndrome (SIJS) may manifest as low back pain, sciatica, or trochanteric pain. Neither patient-reported symptoms nor provocative SIJ maneuvers are sensitive or specific for SIJS when SIJ block is used as the diagnostic gold standard. This has led to increasing diagnostic use of SIJ block, a procedure in which an anesthetic is injected into the joint under arthrographic guidance. However, several arguments cast doubt on the validity of SIJ block as a diagnostic gold standard. Thus, the effects of two consecutive blocks are identical in only 60% of cases, and the anesthetic diffuses out of the joint in 61% of cases, often coming into contact with the sheaths of the adjacent nerve trunks or roots, including the lumbosacral trunk (which may contribute to pain in the groin or thigh) and the L5 and S1 nerve roots. These data partly explain the limited specificity of SIJ block for the diagnosis of SIJS and the discordance between the pain elicited by the arthrography injection and the response to the block. The limitations of provocative maneuvers and SIJ blocks may stem in part from a contribution of extraarticular ligaments to the genesis of pain believed to originate within the SIJs. These ligaments include the expansion of the iliolumbar ligaments, the dorsal and ventral sacroiliac ligaments, the sacrospinous ligaments, and the sacrotuberous ligaments (sacroiliac joint lato-sensu). They play a role in locking or in allowing motion of the SIJs. Glucocorticoids may diffuse better than anesthetics within these ligaments. Furthermore, joint fusion may result in ligament unloading.

Intervertebral disc degeneration associated with lumbosacral transitional vertebrae

We studied 52 patients, each with a lumbosacral transitional vertebra. Using MRI we found that the lumbar discs immediately above the transitional vertebra were significantly more degenerative and those between the transitional vertebrae and the sacrum were significantly less degenerative compared with discs at other levels. We also performed an anatomical study using 70 cadavers. We found that the iliolumbar ligament at the level immediately above the transitional vertebra was thinner and weaker than it was in cadavers without a lumbosacral transitional vertebra.

Instability of the vertebral segment above the transitional vertebra because of a weak iliolumbar ligament could lead to subsequent disc degeneration which may occur earlier than at other disc levels. Some stability between the transitional vertebra and the sacrum could be preserved by the formation of either an articulation or by bony union between the vertebra and the sacrum through its transverse process. This may protect the disc from further degeneration in the long term.

Relation between laminectomy and development of adjacent segment instability after lumbar fusion with pedicle fixation

STUDY DESIGN

A retrospective study of 101 patients who had undergone posterolateral lumbar fusion, to analyze the association between adjacent instability and the extent of laminectomy.

OBJECTIVES

To investigate the hypothesis that the integrity of the posterior complex (spinous process/supraspinous ligament/spinous process) between the fused segments and the neighboring motion segments significantly influences lumbar spine stability.

SUMMARY OF BACKGROUND DATA

Spinal fusion with pedicle fixation accelerates the degeneration of adjacent motion segments. The lowest cranial motion segment is the most common level for the development of adjacent instability. Laminectomy, including removal of the spinous process, supraspinous ligament, interspinous ligament, lamina and ligamentum flavum, jeopardizes the integrity of the posterior complex of the spine.

METHODS

This study enrolled 101 patients, followed up for at least 6 years, who had been treated with posterolateral lumbar fusion with pedicle fixation because of lumbar spondylolisthesis. The diagnosis of adjacent instability depended on the dynamic lateral views of the lumbosacral spine during each follow-up. The integrity of the posterior complex was based on the extent of laminectomy and the fusion level.

RESULTS

At the cranial adjacent motion segment, 2 of 31 (6.5%) patients with preserved posterior complex integrity between the fused segment and motion segment developed adjacent instability, compared with 17 of 70 (24.3%) without preserved posterior complex integrity. At the caudal adjacent motion segment, none of 13 patients (0%) with preserved integrity developed adjacent instability, compared with 3 of 54 (5.6%) without preserved integrity.

CONCLUSIONS

Damaging the integrity of the posterior complex between the fused segments and the neighboring motion segments may jeopardize lumbar spine stability. Sacrificing either the supraspinous ligament or the tendon insertion points on the spinous processes leads to an accelerated development of adjacent instability.