Prognostic radiographic aspects of spondylolisthesis

Radiographic risk factors for degenerative lumbar spondylolisthesis: A comparison with healthy control subjects

Objective

To evaluate the radiologic parameters of degenerative lumbar spondylolisthesis (DLS) and determine the radiographic risk factors for DLS by making comparisons with healthy control subjects.

Methods

Seventy-five patients with L4/5 DLS (Meyerding grade I) and 53 healthy control subjects were analyzed. The L1-S1 disc height index (DHI), L4/5 facet joint angle (FJA), and relative cross-sectional area (RCSA) of paravertebral muscles were measured in both groups. The initial L4/5 DHI (iDHI) before the onset of DLS were estimated based on the L3/4 DHI of the DLS group and DHI of the control group. The sagittal parameters of DLS were also included in this study.

Results

The DHI of L4/5 was lower in the DLS group than in the control group (P < 0.05), but the DHI of the L1-L4 segments were much higher than in the control group (P < 0.05). The initial L4/5 DHI and FJA of the DLS group were significantly higher than those of the control group (P < 0.05). The RCSA of the paravertebral muscles were smaller in the DLS group than in the control group (P < 0.05). Binary logistic regression analysis showed that iDHI, FJA, and RCSA of the total paraspinal muscles were risk factors for DLS. The cutoff values for iDHI, FJA, and RCSA were 0.504, 56.968°, and 1.991 respectively. The iDHI was associated with lumbar lordosis (LL), while L4/5 DHI was associated with the RCSA of the multifidus muscle and psoas major muscle (P < 0.05).

Conclusion

A large initial lumbar disc height, large FJA, and paravertebral muscle atrophy may be risk factors for DLS.

Spondylolysis and End Plate Arthrosis at L5-S1: A Cadaveric Study

This study examined the effect of bilateral and unilateral L5 pars defects on the degree of disk degeneration at the L5-S1 level in cadaveric specimens. An observational study was performed of 690 cadaveric specimens selected at random. These specimens represent individuals who died between 1893 and 1938. The study included 558 male and 132 female cadavers. Of the 120 specimens with L5 spondylolysis, 95 cases were bilateral and 25 were unilateral. The remaining 544 specimens were used as the control cohort. Degenerative disk disease was measured by the classification of Eubanks et al. According to this classification, degenerative disk disease was graded from no arthrosis (grade 0) to complete ankylosis (grade IV). Linear regression analysis corrected for age, sex, and race showed that subjects with bilateral spondylolysis at L5 had a statistically significant increase in the amount of disk degeneration (P=.02) compared with those with unilateral lesions. Student's t tests showed significant differences (P<.001 and P=.002, respectively) in the amount of degeneration seen with both bilateral and unilateral spondylolysis above what would be predicted in the normal control population. A positive correlation was found between the number of pars defects at L5 and the degree of disk degeneration at L5-S1. These results support the idea that individuals with spondylolysis at these levels may be at increased risk for development of low back pain and reduced quality of life. [Orthopedics. 2017; 40(1):e59-e64.].

Spondylolysis and the Sacro-Horizontal Angle in Athletes

The frequency of spondylolysis and the relationship between spondylolysis and the sacro-horizontal angle in 143 athletes and 30 non-athletes is reported. Athletes had a larger sacro-horizontal angle than non-athletes. The sacro-horizontal angle was larger in athletes with spondylolysis as compared with those without. An increased incidence of spondylolysis with an increased angle was demonstrated. It is suggested that an increased sacro-horizontal angle may predispose to spondylolysis, especially in combination with the high mechanical loads sustained in certain sports.

Rationale in the management of 4-level lumbar spondylolyses with or without instability and/or spondylolisthesis

STUDY DESIGN

Case report.

OBJECTIVE

To report the first case of 4-level lumbar spondylolysis in the literature.

SUMMARY OF BACKGROUND DATA

Although there are quite a few reported cases of 2- or 3-level spondylolysis, none reported on 4-level spondylolysis. Management guidelines have not been suggested in literature.

METHODS

A 48-year-old female presented with long-standing severe spinal instability, low back pain, and bilateral neurogenic claudication. Management of the patient with 4-level spondylolysis, varied clinical profile of each of the levels with respect to clinical symptoms and treatment based on the usefulness of pars block is described.

RESULTS

Two levels were treated with intervertebral fusions, 1 level with pars repair, and conservative treatment of the last level pars lysis yielded in good clinicoradiological outcome in our patient.

CONCLUSION

Success of management of multiple lyses depends on the choice of appropriate treatment for each level separately. Pars block is a good invasive investigation to detect the symptomatic levels in a complex situation.

Radiologic evaluation of degeneration in isthmic and degenerative spondylolisthesis

Study Design

A cross-sectional imaging study.

Purpose

The objective was to assess the degree of degeneration and the associated factors through imaging studies of the lesion segment and the adjacent superior and inferior segments of isthmic and degenerative spondylolisthesis.

Overview of Literature

Few articles existed for degeneration and related factors in isthmic and degenerative spondylolisthesis.

Methods

The subjects were 95 patients diagnosed with spondylolisthesis. Simple plain radiographs including flexion and extension and magnetic resonance imaging were used to investigate the degree of translation, disc degeneration, high intensity zone (HIZ) lesion, Schmorl's node (SN) and Modic changes.

Results

Advanced disc degeneration, grade 5, was shown to be significant in the index segment of the isthmic type (p=0.034). Overall, type 2 Modic change was most common in both groups and also, it was observed more in the isthmus group, specifically, the index segment compared to the degenerative group (p=0.03). For the SN, compared to the degenerative type, the isthmus type had a significantly high occurrence in the index segment (p=0.04). For the HIZ lesions, the isthmus type had a higher occurrence than the degenerative type, especially in the upper segment (p=0.03).

Conclusions

Most advanced disc degeneration, fifth degree, SN and Modic change occurred more frequently in the lesions of the isthmus type. HIZ lesions were observed more in the isthmus type, especially in the segment superior to the lesion.

The evaluation of lumbosacral dysplasia in young patients with lumbosacral spondylolisthesis: comparison with controls and relationship with the severity of slip

INTRODUCTION

Comparison of lumbosacral dysplasia between normal individuals and patients with low and high grade spondylolisthesis has not been done previously. The objective of this study is to evaluate the relationship between lumbosacral dysplasia and severity of slip in young patients with lumbosacral spondylolisthesis.

METHODS

Postero-anterior and lateral radiographs of 120 normal individuals and 131 patients with developmental spondylolisthesis (91 low and 40 high grades) were reviewed. Quantitative evaluation of lumbosacral dysplasia was done using 6 criteria involving the degree of laminar dysplasia, degree of facet dysplasia, size of L5 transverse processes, L5/S1 disc height, type of sacral doming and L5 lumbar index. Subjects were categorized as having no/low, moderate or severe dysplasia based on the total dysplasia score. Comparisons in total dysplasia score between normal, low grade and high grade groups were performed and the correlation between degree of dysplasia and percentage of slip was assessed.

RESULTS

Most normal individuals (88.3%) had no/low dysplasia; most patients with low grade spondylolisthesis (61.5%) had moderate dysplasia, while most patients with high grade spondylolisthesis (72.5%) had severe dysplasia. There was a significant difference in dysplasia between normal individuals and patients with spondylolisthesis. Dysplasia also varied significantly between low and high grade spondylolisthesis. There was a strong positive correlation (r = 0.63) between severity of dysplasia and percentage of slip.

CONCLUSION

There is a significant relationship between the severity of spondylolisthesis and lumbosacral dysplasia, with mainly no/low dysplasia observed in controls and increasing total dysplasia scores in higher grades of spondylolisthesis. In addition, a variable degree of dysplasia was found within groups with low or high grade spondylolisthesis, suggesting that different subgroups of patients exist with regard to dysplasia. Thus the degree of dysplasia varies in spondylolisthesis and it is possible that different grades of dysplasia could relate to different prognoses or outcomes with treatment.

Correlation of sacropelvic geometry with disc degeneration in spondylolytic cadaver specimens

STUDY DESIGN

An anatomic study of sacral inclination, pelvic incidence, pelvic lordosis, and disc degeneration in cadaveric lumbar spines.

OBJECTIVE

To evaluate the relationship between sacropelvic parameters and disc degeneration in subjects with bilateral spondylolysis at L5.

SUMMARY OF BACKGROUND DATA

L5-S1 disc degeneration is greater in patients with spondylolytic defects (L5-S1) than with an intact pars interarticularis secondary to the instability caused by spondylolysis. Sacral inclination, pelvic incidence, and pelvic lordosis affect sagittal balance and axial forces on the L5-S1 disc.

METHODS

An observational study was performed on 120 cadaveric specimens with spondylolysis (L5-S1) identified of 3100 total cadaveric specimens. Nine specimens were excluded because of incomplete or degraded skeletal elements; 10 were excluded for having unilateral defects only. The specimens were evaluated for sacral inclination, pelvic incidence, and pelvic lordosis. Disc degeneration and facet arthrosis at L4-L5 and L5-S1 were measured by the classification of Eubanks et al. Linear regression analyses were then used to determine the relationship between sacropelvic parameters and degeneration at the L5-S1 segment, correcting for confounding factors such as age, sex, and race.

RESULTS

Linear regression demonstrated a significant association between sacral inclination and disc degeneration at L5-S1 (P = 0.018). Specimens were then divided into two groups, those in the highest quarter of pelvic incidence, and the remainder. Spearman rank correlation demonstrated a significant association between disc degeneration at L5-S1 and the highest quarter of pelvic incidence (P = 0.017). Increasing pelvic lordosis was also associated with an increase in facet arthrosis at L4-L5 (P = 0.006).

CONCLUSION

The findings of this study show a relationship between the sacropelvic geometry and the degree of L5-S1 disc degeneration as well as L4-L5 facet degeneration in spondylolytic specimens. This relationship may prove useful in predicting the course of disc degeneration in patients with spondylolysis.

Biomechanical rationale of sacral rounding deformity in pediatric spondylolisthesis: a clinical and biomechanical study

AIM

Rounding surface of the sacral dome and wedging deformity of the vertebral body are commonly observed in patients with isthmic spondylolisthesis. Recently, an animal study showed that the deformity can be caused by the growth plate involvement in the immature pediatric vertebral body after biomechanical alteration due to the pars defects. However, the pathomechanism and biomechanics of these deformities have yet to be clarified. To demonstrate that the sacral rounding deformity observed in pediatric patients with spondylolisthesis can be reversed, and to understand the pathomechanism of the deformity from the biomechanical standpoint by analyzing changes of stress around the growth plate of the vertebral body due to spondylolysis.

METHOD

Three-dimensional finite element pediatric lumbar models of the L3-L5 segment were utilized. Unlike the adult model, this pediatric model had growth plates and apophyseal rings. We analyzed stress distribution in response to 351°N axial compression and 10 N m moment in flexion, extension, lateral bending, and axial rotation. Bilateral spondylolysis was created in the model at the L4 level. The stress in the bilateral defect model was compared to the intact model predictions and the results obtained in the pediatric patients with sacral rounding deformity.

RESULTS

Two patients presented rounding deformity of the anterior upper corner at S1 at the initial visit. They were asked to stop sports activities and use a soft trunk brace. Twelve months later, no rounding deformity was observed on the radiographs indicating that this deformity was reversible in pediatric cases. The biomechanical study indicated that in the pediatric spondylolytic spine, mechanical stress increased at the anterior upper corner during lumbar motion.

CONCLUSION

In the presence of spondylolysis, mechanical stress increases in the growth plate at the anterior upper corner. Repetitive increases of mechanical stress may cause rounding deformity of the sacral dome mediated by growth plate involvement. When mechanical stress at the growth plate is reduced by wearing a brace, the proper functioning of the growth plate can help to remodel the sacral dome to its normal shape.

Lumbar spondylolysis: a review

Spondylolysis is an osseous defect of the pars interarticularis, thought to be a developmental or acquired stress fracture secondary to chronic low-grade trauma. It is encountered most frequently in adolescents, most commonly involving the lower lumbar spine, with particularly high prevalence among athletes involved in certain sports or activities. Spondylolysis can be asymptomatic or can be a cause of spine instability, back pain, and radiculopathy. The biomechanics and pathophysiology of spondylolysis are complex and debated. Imaging is utilized to detect spondylolysis, distinguish acute and active lesions from chronic inactive non-union, help establish prognosis, guide treatment, and to assess bony healing. Radiography with satisfactory technical quality can often demonstrate a pars defect. Multislice CT with multiplanar reformats is the most accurate modality for detecting the bony defect and may also be used for assessment of osseous healing; however, as with radiographs, it is not sensitive for detection of the early edematous stress response without a fracture line and exposes the patient to ionizing radiation. Magnetic resonance (MR) imaging should be used as the primary investigation for adolescents with back pain and suspected stress reactions of the lumbar pars interarticularis. Several imaging pitfalls render MR imaging less sensitive than CT for directly visualizing the pars defects (regional degenerative changes and sclerosis). Nevertheless, the presence of bone marrow edema on fluid-sensitive images is an important early finding that may suggest stress response without a visible fracture line. Moreover, MR is the imaging modality of choice for identifying associated nerve root compression. Single-photon emission computed tomography (SPECT) use is limited by a high rate of false-positive and false-negative results and by considerable ionizing radiation exposure. In this article, we provide a review of the current concepts regarding spondylolysis, its epidemiology, pathogenesis, and general treatment guidelines, as well as a detailed review and discussion of the imaging principles for the diagnosis and follow-up of this condition.

Association between computed tomography-evaluated lumbar lordosis and features of spinal degeneration, evaluated in supine position

BACKGROUND CONTEXT

Few studies have directly evaluated the association of lumbar lordosis and segmental wedging of the vertebral bodies and intervertebral discs with the prevalence of spinal degenerative features.

PURPOSE

To evaluate the association of computed tomography (CT)-evaluated lumbar lordosis as well as segmental wedging of the vertebral bodies and that of the intervertebral discs with various spinal degenerative features.

STUDY DESIGN

This cross-sectional study was a nested project to the Framingham Heart Study.

PATIENT SAMPLE

A random consecutive subset of 191 participants chosen from the 3,590 participants enrolled in the Framingham Heart Study who underwent multidetector CT to assess aortic calcification.

OUTCOME MEASURES

Dichotomous variables indicating the presence of intervertebral disc narrowing, facet joint osteoarthritis, spondylolysis, spondylolisthesis and spinal stenosis, and density (in Hounsfield units) of multifidus and erector spinae muscles were evaluated on supine CT, as well as the lordosis angle (LA) and the wedging of the vertebral bodies and intervertebral discs. The sum of vertebral bodies wedging (ΣB) and sum of intervertebral discs wedging (ΣD) were used in the analyses.

METHODS

Mean values (±standard deviation [SD]) of LA, ΣB, and ΣD were calculated in males and females and compared using the t test. Mean values (±SD) of LA, ΣB, and ΣD in four age groups (<40, 40-49, 50-59, and 60+ years) were calculated. We tested the linear relationship between LA, ΣB, and ΣD and age groups. We evaluated the association between each spinal degenerative feature and LA, ΣB, and ΣD using multiple logistic regression analysis where studied degenerative features were the dependent variable and all LA, ΣB, and ΣD (separately) as well as age, sex, and body mass index were independent predictors.

RESULTS

Lordosis angle was slightly lower than the normal range for standing individuals, and no difference was found between males and females (p=.4107). However, the sex differences in sum of vertebral bodies wedging (ΣB) and sum of intervertebral discs wedging (ΣD) were statistically significant (.0001 and .001, respectively). Females exhibit more dorsal wedging of the vertebral bodies and less dorsal wedging of the intervertebral discs than do males. All these parameters showed no association (p>.05) with increasing age. Lordosis angle showed statistically significant association with the presence of spondylolysis (odds ratio [95% confidence interval]: 1.08 [1.02-1.14]) and with the density of multifidus (1.06 [1.01-1.11]) as well as a marginally significant association with isthmic spondylolisthesis (1.07 [1.00-1.14]). ΣB showed a positive association with degenerative spondylolisthesis and disc narrowing (1.14 [1.06-1.23] and 1.04 [1.00-1.08], correspondingly), whereas ΣD showed a negative one (0.93 [0.87-0.98] and 0.93 [0.89-0.97], correspondingly).

CONCLUSIONS

Significant associations were found between lumbar lordosis evaluated in supine position and segmental wedging of the vertebral bodies and intervertebral discs and the prevalence of spondylolysis and spondylolisthesis. Additional studies are needed to evaluate the association between spondylolysis, isthmic and degenerative spondylolisthesis and vertebral and disc wedging at the segmental level.

Geometry of the vertebral bodies and the intervertebral discs in lumbar segments adjacent to spondylolysis and spondylolisthesis: pilot study

The objective is to evaluate the geometric parameters of vertebral bodies and intervertebral discs in spinal segments adjacent to spondylolysis and spondylolisthesis. This pilot cross-sectional study was an ancillary project to the Framingham Heart Study. The presence of spondylolysis and spondylolisthesis as well as measurements of spinal geometry were identified on CT imaging of 188 individuals. Spinal geometry measurements included lordosis angle, wedging of each lumbar vertebra and intervertebral disc. Last measurements were used to calculate ΣB, the sum of the lumbar L1-L5 body wedge angles; and ΣD, the sum of the lumbar L1-L5 intervertebral disc angles. Using Wilcoxon-Mann-Whitney test we compared the geometric parameters between individuals with no pathology and ones with spondylolysis (with no listhesis) at L5 vertebra, ones with isthmic spondylolisthesis at L5-S1 level, and ones with degenerative spondylolisthesis at L5-S1 level. Spinal geometry in individuals with spondylolysis or listhesis at L5 shows three major patterns: In spondylolysis without listhesis, spinal morphology is similar to that of healthy individuals; In isthmic spondylolisthesis there is high lordosis angle, high L5 vertebral body wedging and very high L4-5 disc wedging; In degenerative spondylolisthesis, spinal morphology shows more lordotic wedging of the L5 vertebral body, and less lordotic wedging of intervertebral discs. In conclusion, there are unique geometrical features of the vertebrae and discs in spondylolysis or listhesis. These findings need to be reproduced in larger scale study.

Operative treatment of isthmic spondylolisthesis in children: a long-term, retrospective comparative study with matched cohorts

The purpose of the present study was to compare the long-term clinical, functional and radiographic outcomes of young patients operated on before or at the onset of puberty (Children) and those operated on after that (Adolescents). The study group consisted of 298 patients operated on under the age of 20 years; 55 of them were operated on before or at the onset of growth spurt (29 females<12.5 years, 26 males<14.5 years). Preoperative data were retrieved from patients' records. After mean follow-up of 17 years (10.7-26.3), physical examination, radiographic measurements and functional testing were performed by independent observers. SRS-24, Oswestry Disability Index (ODI), and Visual Analogue Scale (VAS) were utilised to evaluate health-related quality of life. The data were compared between the two age groups in the whole study population and in 41 pairs of patients matched by gender, operative method, severity of preoperative slip, and age at follow-up. Preoperatively, one-third of children did not have significant pain symptoms. They were operated upon for resistant postural anomalies in combination with high risk of slip progression. All of the adolescents had low-back pain as the main clinical symptom. The outcomes were satisfactory in both groups in the whole population (children vs. adolescents; low-grade slip: SRS-24: 95.9 vs. 92.0, ODI: 5.2 vs. 7.5, VAS low-back pain: 18.9 vs. 21.2; high-grade slip: SRS-24: 95.6 vs. 90.6, ODI: 3.4 vs. 6.9, VAS low-back pain: 10.5 vs. 22.1). The differences were statistically significant for ODI and VAS in high-grade patients in favor of the children. The clinical relevance of these differences seems to be minimal. The results of the comparison of the matched cohorts were comparably good. One-fifth of the whole study group had a non-union which did not affect the final outcome. In the children with high-grade slips, there was a mean slip improvement of 14 percentage points due to remodelling. The overall complication rate in the whole population was 7.7%. In conclusion, spinal fusion can be carried out at an early age for low- and high-grade spondylolisthesis with good long-term clinical, functional, radiographic and health-related quality-of-life outcomes when the indications are met.

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.

Uninstrumented in situ fusion for high-grade childhood and adolescent isthmic spondylolisthesis: long-term outcome

BACKGROUND

Intermediate-term radiographic studies have shown that anterior and circumferential techniques result in high fusion rates in patients with high-grade spondylolisthesis, whereas posterolateral fusion is less successful. We are not aware of any long-term comparative studies in which these three methods have been evaluated with regard to functional outcome, including systematic spinal mobility and trunk strength measurements.

METHODS

Sixty-nine of eighty-three consecutive patients with high-grade isthmic spondylolisthesis who underwent posterolateral (twenty-one), anterior (twenty-three), or circumferential (twenty-five) uninstrumented spondylodesis between 1977 and 1991 participated in the study. The average duration of follow-up was 17.2 years. Radiographs that were made preoperatively and at the time of the most recent follow-up were assessed with regard to fusion quality and degenerative changes. Outcome was assessed at the time of the most recent follow-up by independent observers on the basis of a physical examination, spinal mobility and nondynamometric trunk strength measurements, and Oswestry Disability Index scores.

RESULTS

The mean preoperative vertebral slip was 61% in the posterolateral fusion group, 63% in the anterior fusion group, and 71% in the circumferential fusion group. The final fusion rate was 86% (eighteen of twenty-one) in the posterolateral fusion group, 100% (twenty-three of twenty-three) in the anterior fusion group, and 96% (twenty-four of twenty-five) in the circumferential fusion group. A decrease in lumbar intervertebral disc height at the first mobile level superior to the fusion was noted in five patients in the posterolateral fusion group, seven patients in the anterior fusion group, and one patient in the circumferential fusion group (p = 0.037). The mean Oswestry Disability Index score was 9.7 for the posterolateral fusion group, 8.9 for the anterior fusion group, and 3.0 for the circumferential fusion group (p = 0.035). Nondynamometric trunk strength measurements corresponded with referential values. Abnormally low lumbar flexion affected the posterolateral and circumferential fusion groups more often than the anterior fusion group (p = 0.0015). The percentage of slip showed inverse correlations with lumbar flexion, lumbar extension, and trunk side-bending.

CONCLUSIONS

As assessed on the basis of patient-based outcomes, circumferential in situ fusion provided slightly better long-term results than did posterolateral or anterior in situ fusion. When the radiographic and functional results were combined with the patient-based outcomes, the overall differences between the three groups were small.

Abnormal motion in spondylolytic spondylolisthesis

STUDY DESIGN

A retrospective, cohort study of the kinematics of the lumbar spine of patients with spondylolisthesis compared with asymptomatic normal subjects.

OBJECTIVE

To determine if abnormal motion could be detected in the radiographs of patients with spondylolisthesis.

SUMMARY OF BACKGROUND DATA

Contrary to the prevailing conviction that lumbar segments affected by lytic spondylolisthesis are unstable, multiple studies have failed to find evidence of increased or abnormal motion at these segments. However, these studies did not use techniques that might reveal abnormalities in the quality of motion, as opposed to its magnitude.

METHODS

The flexion-extension radiographs of 13 patients with spondylolytic spondylolisthesis were analyzed to determine the location of their instantaneous centers of rotation, and their magnitudes of translation and sagittal rotation. Normative data were obtained by applying the same techniques to the radiographs of 20 asymptomatic subjects.

RESULTS

All but 1 of the 13 patients had at least one segment with abnormal motion. Only one patient had excessive translation at the lytic segment. Five patients had minor abnormalities affecting either the lytic segment or ones above, and 6 had paradoxical motion at the lytic segment in which the center of rotation was located above L5, instead of below, and in which L5 translated backward instead of forward during flexion.

CONCLUSIONS

A proportion of patients with spondylolisthesis had highly abnormal movements but ones with normal magnitudes of motion. Determining the instantaneous axes of rotation reveals the abnormal quality of motion.

Abnormal spinal anatomy in 27 cases of surgically corrected spondyloptosis: proximal sacral endplate damage as a possible cause of spondyloptosis

STUDY DESIGN

Retrospective review.

OBJECTIVES

To review the findings in the cases of spondyloptosis we have treated and to postulate on the possible cause of spondyloptosis.

SUMMARY OF BACKGROUND DATA

Spondyloptosis (Grade V spondylolisthesis) is rare, even though spondylolisthesis is a relatively common condition. While it is known that progression to spondyloptosis occurs in patients with developmental spondylolisthesis in their childhood and/or adolescent years, the precise factors leading to progression are not known.

METHODS

Between 1979 and 2002, 27 patients with spondyloptosis were treated surgically with L5 resection and reduction of L4 onto S1. During the treatment process, detailed observations of the surgical findings were made through clinical and radiologic means. Six anatomic parameters (pars interarticularis defects, spina bifida of the L5 or sacral segments, dysplasia of the L5-S1 facet joints, L5-S1 disc degeneration, trapezoidal shape of L5, and rounding of the proximal end of the sacrum) were specifically studied.

RESULTS

Pars interarticularis defects were present in 24 patients (88.9%), facet dysplasia in 16 patients (59.2%), spina bifida in 24 patients (88.9%), disc degeneration in 25 (92.6%), trapezoidal L5 in 20 patients (74.1%), and rounding of the proximal end of S1 in all 27 patients (100%).

CONCLUSIONS

Rounding of the proximal sacral endplate was the only constant abnormal anatomic feature in the patients. Damage to the proximal sacrum and sacral growth plate during late childhood and early adolescence, similar to the epiphyseal injury that produces Blount's disease, and slipped capital femoral epiphysis seem to be key factors permitting the progression of developmental spondylolisthesis to spondyloptosis.

Long-term clinical, functional and radiological outcome 21 years after posterior or posterolateral fusion in childhood and adolescence isthmic spondylolisthesis

Long-term radiological studies have shown that a high rate of fusion can be achieved with posterolateral spondylodesis. Radiological findings, however, do not always correlate with patient satisfaction and outcome. No studies have been conducted on the long-term results of functional outcome, including spinal mobility and trunk strength measurements, after operative treatment of spondylolysis and spondylolisthesis, as compared with the reference population. Of 129 consecutive patients with isthmic spondylolisthesis operated on with spondylodesis between 1977 and 1987, 107 (83%) participated in the study. Posterior spondylodesis was performed in 29 (27%) patients and posterolateral spondylodesis in 78 (73%) patients. The average follow-up time was 20.9 years (range 15.1-26.2 years). Radiographs obtained preoperatively and at the 2-year and final follow-ups were assessed for quality of the fusion and degenerative changes. Outcome was assessed at the last follow-up by physical examination, spinal mobility and non-dynamometric trunk strength measurements, and calculation of Oswestry disability index (ODI) scores. The fusion rate was 66% after posterior fusion and 83% after posterolateral fusion. Degenerative changes in the lumbar intervertebral discs above the fusion level were noted in 13 (12%) patients. At the final follow-up 14% of patients reported back pain often or very often. The mean ODI score was 7.6 (0-68). Moderate disability was found in 6% of patients and severe disability in 1%; one patient was crippled. No correlation was found between disc degeneration or solidity of the fusion and the ODI score. Non-dynamometric trunk strength measurements corresponded with the reference values. Lumbar flexion, but not extension, was diminished when compared with that of the reference population. The overall long-term clinical outcome is good in patients with spondylolysis and spondylolisthesis operated on with posterior or posterolateral fusion. The clinical and radiological outcomes do not, however, appear to correlate with each other. Lumbar flexion is diminished, but the patients perform, on average, as well as the general population in non-dynamometric trunk strength measurements.

The relationship between lumbar lordosis and radiologic variables and lumbar lordosis and clinical variables in elderly, African-American women

Several authors have hypothesized that there is a link between lumbar lordosis and low back pain. These relationships have not been previously described in a sample consisting exclusively of elderly, African-American women. The purpose of this study was to describe the relationship between lumbar lordosis and radiologic variables and lumbar lordosis and clinical variables in elderly, African-American women. A total of 475 African-American women enrolled in the multicenter Study of Osteoporotic Fractures participated in this ancillary, cross-sectional, study of lumbar lordosis. These women received lumbar spine radiographs and completed a questionnaire on low back pain and its impact on their daily lives. Lumbar lordosis tertiles were created based on radiographic measurements. Comparisons were made between the tertiles for differences in radiologic and clinical variables. Significant differences (p < 0.0025) were observed between the lordosis tertiles and the presence of spondylolisthesis, intervertebral disc space, and vertebral wedging. No significant differences were observed between the lordosis tertiles for the occurrence of low back pain, symptoms associated with low back pain, and disability experienced from low back pain. The degree of lumbar lordosis was associated with radiologic variables but was not associated with symptoms or decreased function from low back pain. These findings question the clinical utility of the lumbar lordosis measurement in elderly, African-American women.

Radiographic spinal profile changes induced by cage design after posterior lumbar interbody fusion preliminary report of a study with wedged implants

STUDY DESIGN

A prospective comparative radiographic study between two geometrically varying implants utilized in single-level posterior lumbar interbody fusion (PLIF) was performed.

OBJECTIVE

The aim of this study was to determine the influence of 4 degrees wedged cages on postoperative lateral lumbar spinal profile.

SUMMARY OF BACKGROUND DATA

The biomechanical and clinical importance of realigning the sagittal lumbar profile in surgical management of spinal instabilities is known. Wedged cages are therefore increasingly attaining popularity in PLIF. As yet the significance of wedged implants on postoperative sagittal spinal profile has not been assessed.

METHODS

Forty patients were randomly assigned to two equal-sized groups. In one group rectangular cages and in the second group cages with a wedged design and an inclination of 4 degrees were implanted. Quantitative assessment of the lumbar spinal profile on standing neutral lateral radiographs was performed before surgery as well as 6 weeks and 12 months after surgery. Results were statistically compared.

RESULTS

A significant improvement of lumbar sagittal profile after use of 4 degrees wedged compared with nonwedged cages was not found. The greatest effect on lumbar profile and segmental lordosis was observed in fusion of segment L4-L5 with 4 degrees wedged cages.

CONCLUSIONS

These results show that normal sagittal alignment after single-level lumbar fusion can be achieved with rectangular and 4 degrees wedged cages. Although results after utilization of 4 degrees wedged cages do not significantly differ, these implants offer the surgeon one more sizing variation with which physiologic lumbar lordosis may be attained. The biomechanical implications of wedged implants on the rigidity of a fused segment remain to be analyzed.

Biomechanical functions of the iliolumbar ligament in L5 spondylolysis

Abiomechanical study of the functions of the iliolumbar ligament in L5 spondylolysis was performed. Five fresh cadaveric specimens were used. The bilateral ilia and sacrum were fixed. Four kinds of pure moments (10 Nm) were applied to the specimens at the top (L4) vertebra: flexion, extension, and right and left axial rotations. The three-dimensional position of the L5 vertebra was measured after serial transections in: (1) the intact condition; (2) bilateral pars interarticulares of L5 transected; (3) anterior bands of the iliolumbar ligaments transected; and (4) posterior bands of the iliolumbar ligaments transected. In L5 spondylolysis, flexion and axial rotation of L5 on S1 are significantly regulated by the anterior and posterior bands of the iliolumbar ligaments (especially by the posterior bands of the ligaments). The integrity of the ligament may determine the stability of the lumbosacral junction and the amount of forward slipping of the L5 vertebra.

Instability in spondylolisthesis

Anteroposterior translation as a sign of segmental instability was documented by traction-compression radiography in the majority of lumbar segments presenting lytic or degenerative spondylolisthesis with normal disc space height. Severity of lower back pain symptoms correlated with the degree of instability, but not with the amount of static spondylolisthetic displacement. Unstable spondylolistheses exhibited decreased viscoelastic behavior with creep, the degree of the vertebral displacement being dependent on the amount and duration of load. Disc degeneration and traction spurs seemed to be factors that may stabilize spondylolisthesis, even at an early age.

The etiology of spondylolysis. A retrospective radiographic study

One hundred and thirty-five patients with lysis in the fifth (lowest) lumbar vertebra and 24 patients with L4 lysis were compared retrospectively with respect to radiographic variables and the occurrence of trauma before symptom onset. Hypoplasia occurred only in the L5 lysis group, whereas trauma as a symptom-precipitating factor was frequent in the L4 group. These observations suggest the possibility of different etiologies: trauma may contribute to lysis in a normal L4 vertebra, and inherited hypoplasia of the lumbosacral junction may lead to L5 lysis.