L5-S1 disc degeneration and the anatomic parameters of the iliac crest: imaging study

The Effect of L5 Morphology on Prevention of L5-S1 Degeneration Following Floating Fusion for Degenerative Spine Disorders

STUDY DESIGN

Retrospective Study.

OBJECTIVES

The selection of floating fusion or lumbosacral fusion arises when treating patients with instability or stenosis of the lower lumbar spine concomitantly radiographic degeneration of L5-S1. This study aimed to investigate the preoperative anatomical or morphological factors affecting the survivorship of the L5-S1 after floating fusion.

METHODS

This study included 77 patients who had undergone floating fusion surgery through the TLIF approach. Preoperative radiographic parameters were evaluated using anteroposterior and lateral lumbar spine radiographs. The patients were divided into two groups according to the Modified Pfirrmann Grading and total endplate score. Multivariable regression analysis was performed to explore the relationships between the anatomical or morphological characteristics of L5 and the degeneration of L5-S1.

RESULTS

The disc degeneration group exhibited a smaller height ratio of the iliac crest (Hi) and a less L5 deep position. Furthermore, the right/left height of L4 (Hr/Hl) and the right/left width of transverse process of L5 (CRt/CLt) were significantly higher in the disc and endplate degeneration groups. Multiple logistic regression analysis revealed that Hi and CRt were independently associated with L5-S1 disc degeneration, whereas Hr was a significant risk factor for L5-S1 endplate degeneration.

CONCLUSION

Anatomical and morphological characteristics of L5, such as smaller Hi, higher CRt and Hr, were associated with an increased risk of L5-S1 degeneration in patients after floating fusion. These findings may indicate the fusion level when addressing lower lumbar degenerative diseases and the concurrent radiographic degeneration of L5-S1.

Patient-related risk factors and lifestyle factors for lumbar degenerative disc disease: a systematic review

OBJECTIVE

Back pain is a very widespread disease pattern and is one of the most frequent causes for consultation of a physician in general. In most cases, discogenic changes are the pathomorphological correlate of back pain. Numerous risk factors have been identified for these degenerative changes, but the influence and significance of the risk factors remain unclear, which was the aim of this systematic review.

METHODS

A systematic literature search of the commonly used Pubmed database was performed using specific MESH terms. Further selection of the included studies was performed according to the PRISMA scheme, taking into account scientific merit as well as the relation to the research question.

RESULTS

A total of 111 studies out of 1035 found were finally included in the literature search. 134 risk factors for disc degeneration and disc herniation were identified. These were divided into (1) patient-specific risk factors (n░=░34), (2) radiological risk factors (n░=░31), (3) lifestyle risk factors (n░=░6), (4) workplace-related risk factors (n░=░12), (5) genetic risk factors (n░=░50), and (6) other risk factors (n░=░1). Non-adjustable risk factors were age >50 years (OR 1.7/year), female gender (OR 1.41), family disposition (OR 4.0), comorbidities like atherosclerosis (OR 2.24), arthritic changes in other joints (OR 3.1) and history of injuries of the back (OR 3.1). Adjustable factors were elevated BMI (OR 2.77), comorbidities like hypertension (OR 1.25), dyslipidemia (OR 1.26) and diabetes mellitus (OR 6.8), as well as lifestyle habits like smoking (OR 3.8).

DISCUSSION

In summary, intervertebral disc degenerations and herniations represent multifactorial events whose risk factors can be partly influenced and partly not influenced. This systematic review highlights the current state of knowledge as a basis for creating patient-specific algorithms to calculate risk for the development or progression of degenerative disc changes and disc herniations.

CT observation of L5 pedicle screw fixation shielding by the iliac wing width and height

OBJECTIVE

The height and width of the iliac wing were measured using three-dimensional computed tomography(3D-CT), and the extent to which the iliac wing occluded the entry point of the 5th lumbar vertebra pedicle screw(L5PS) was observed and graded according to severity. The overall goal was to study the influence of the height and width of the iliac wing on L5PS insertion.

PATIENTS AND METHODS

This study included 350 cases (179 males and 171 females) where the L1-S2 region was obtained. We reconstructed 3D-CT in our study for anatomic analysis. The width and height of the iliac wing were measured on CT axial and oblique sagittal images, respectively. The degree of the L5PS entry point was determined by the data of iliac wing width and height, and divided into 0, I, II and III levels. The association between width and height of the iliac wing among males and females was also analyzed in this paper.

RESULTS

The incidence of shielding of the L5PS entry point by the height and width of the ilium wing were 20.0 % and 19.4 %, respectively. The overall incidence of obstruction of L5PS by the width of the ilium wing was 27.3 % in males and 12.3 % in females. In total, there were 27, 14, and 8 male patients with level I, II, and III shielding, respectively. There were 12, 7, and 2 females with level I, II, and III shielding, respectively. The overall incidence with which the height of the ilium wing obstructed L5PS was 24.0 % in males and 14.6 % in females, of which there were 23 males with level Ⅰ shielding, 16 males with level Ⅱ shielding, 4 males with level Ⅲ shielding, 13 females with level Ⅰ shielding, 8 females with level Ⅱ shielding, and 4 females with level Ⅲ shielding.

CONCLUSIONS

The height of the ilium caused obstruction of the L5PS more frequently than the width of the ilium, and males had a higher incidence of iliac wing occlusion than females at both the height and width. The degree of L5PS entry point shielding by the iliac wing width along the horizontal axis was not completely consistent with that of L5PS shielding on the oblique sagittal plane.