Prevention of Adjacent Segmental Disease after Fusion in Degenerative Spinal Disorder: Correlation between Segmental Lumbar Lordosis Ratio and Pelvic Incidence–Lumbar Lordosis Mismatch for a Minimum 5-Year Follow-up

STUDY DESIGN: Retrospective study. PURPOSE: Associations among risk factors related to adjacent segmental disease (ASD) remain unclear. We evaluated the risk factors and segmental lordosis ratio to prevent ASD developing after lumbar spinal fusion. OVERVIEW OF LITERATURE: Risk factors related to ASD development are age, sex, obesity, pre-existing degeneration, number of fusion segments, and decreased postoperative lumbar lordosis (LL). However, the associations among these factors are still unclear and should be clearly identified. METHODS: We retrospectively reviewed data on 274 patients who underwent lumbar spinal fusion of three segments or below for lumbar degenerative disease from January 2010 to December 2012, with over 5 years of follow-up. Patients with preoperative sagittal vertical axis (SVA) >5 cm were excluded due to sagittal imbalance. A total of 37 patients with ASD and 40 control patients (CTRL) were randomly selected in a similar distribution of matching variables: age, sex, and preoperative degenerative changes. Sex, age, number of fusion segments, radiologic measurements, L4–5–S1/L1–S1 LL ratio, and spinopelvic parameters (pelvic incidence [PI], pelvic tilt [PT], sacral slope [SS], and SVA) were analyzed. Logistic regression was used to analyze the correlation between PI–LL mismatch and L4–5–S1 segmental lordosis rate. RESULTS: No significant difference was found between ASDs and CTRL groups regarding age, sex, number of fusion segments, fusion method, and preoperative and postoperative spinopelvic parameters (PI, SS, PT, and LL). However, regarding the L4–5–S1/L1–S1 lordosis ratio, 50% (p=0.045), 60% (p=0.031), 70% (p=0.042), 80% (p=0.023), and 90% (p=0.023) were statistically significant; 10 group, and the difference was statistically significant (p=0.048). CONCLUSIONS: Patients with a postoperative L4–5–S1/L1–S1 lordosis ratio >50% had less occurrence of ASD. Correcting LL according to PI and physiologic segmental lordosis ratio is important in preventing ASD.

Restoration of Segmental Lordosis and Related Factors in Interbody Fusion for Degenerative Lumbar Disease

STUDY DESIGN: A retrospective study. OBJECTIVES: To analyze restoration of segmental lordosis and factors related to interbody fusion and the fusion rate with degenerative lumbar disease. SUMMARY OF LITERATURE REVIEW: Few studies have addressed the restoration of segmental lordosis and factors related to interbody fusion for degenerative lumbar disease. MATERIALS AND METHODS: Records of 43 patients treated by anterior lumbar interbody fusion (ALIF) or posterior lumbar interbody fusion (PLIF) surgery from 2011 to 2013 were reviewed. ALIF used a metal cage with a 10degrees lordotic angle and PLIF used a metal cage with an 8degrees lordotic angle. Preoperative, postoperative, and at least 1 year outcomes were analyzed from radiographs. As a related factor, segmental flexibility, disc height, osteophytes, vaccuum disc, hypertrophic facet, spondylolisthesis, and endplate violation were analyzed. We also analyzed the bony union rate. RESULTS: The segmental lordotic angle was 4.67degrees before surgery, improved to 10.43degrees after surgery, and was 9.32degrees at the final follow-up. Comparing between the ALIF and PLIF at the L3-4 level in a similar number of patients revealed 7.24degrees and 4.61degrees restoration after ALIF and PLIF surgery, postoperatively. The difference was statistically significant (p=0.011). Segmental flexibility had a statistically significant positive correlation (p=0.013). Lower disc height and osteophytes limited restoration of segmental lordosis, but vaccuum disc was restored well after interbody fusion. Bony union was achieved in 92.8% of the cases. CONCLUSIONS: Intebody fusion, especially ALIF surgery, results in acceptable restoration of segmental lordosis. Even with narrowed disc space or osteophytes, remained segmental flexibility is an important factor of segmental lordosis restoration.

Lumbar Lordosis Restoration with an Eight Degree Cage in Posterior Lumbar Interbody Fusion for Lumbar Degenerative Disease / 대한정형외과학회잡지

PURPOSE: The purpose of this study is to determine how much lumbar lordosis is restored with an eight degree cage in posterior lumbar interbody fusion (PLIF) for degenerative lumbar spinal disease. MATERIALS AND METHODS: A total of 61 patients who underwent PLIF using a metal cage with an eight degree lordotic angle were evaluated. Cases with complications such as subsidence of the cage or instrument failure were excluded from this study. Lumbar lordosis, segmental lordosis, disc height, and bony union were analyzed on the patients' radiographs. RESULTS: Cages were inserted at L3-4 in 17 patients, L4-5 in 54 patients, and L5-S1 in 20 patients. The number of fused level was 1 segment in 32 patients, 2 segments in 27 patients, and 3 segments in 2 patients. The lumbar lordosis was 33.6degrees before surgery, improved to 37.6degrees after surgery, and then was changed to 37.0degrees at the final follow-up. Segmental lordosis at which the cage was inserted was restored after surgery at L4-5 and L5-S1. Disc height was improved with surgery as well. Satisfactory bony fusion was achieved in 95% of the patients. CONCLUSION: PLIF using an eight degree lordotic cage for degenerative spinal disease resulted in restoration of lumbar lordosis and segmental lordosis, although these angles showed some loss of correction after surgery.

Restoration of Lumbar Lordosis After Posterior Lumbar Interbody Fusion with 4 Degree Cage in Degenerative Spinal Disease

STUDY DESIGN: Retrospective radiological evaluation. OBJECTIVES: This purpose of this study is to determine how much lumbar lordosis and disc heights are restored after posterior lumbar interbody fusion (PLIF) with cage in degenerative spinal disease. SUMMARY OF LITERATURE REVIEW: Restoration of lumbar lordosis in lumbar spine surgery is crucial for clinical outcomes, but there are few studies about the relationship between restoration of lumbar lordosis and cage. MATERIAL AND METHOD: Eighty-one patients with degenerative spinal diseases underwent PLIF using metal cage with 4degrees lordotic angle. The mean age was 61 year-old (range 38-83 years). Cases with late complications including nonunion, subsidence of cage and instrument failure were excluded in this study. Lumbar lordosis, segmental lordosis, disc height, and sagittal alignment were analyzed on radiographs. RESULTS: The fused level was one segment in 62 patients and two segments in 19 patients. All patients had the fusion from L3 to the sacrum. Preoperative lumbar lordosis was 34.2degrees, improved to 34.6degrees after surgery, and then changed to 32.2degrees at the final follow-up, demonstrating that the cage with 4degrees lordotic angle was not effective to restore lumbar lordosis. Segmental lordosis at the level of cage decreased at the final follow-up as compared to preoperative value at all segments. Disc height was improved at the final follow-up as compared to preoperative value. CONCLUSION: Disc height was restored after PLIF using cage in the surgery for degenerative lumbar spine. However, lumbar lordosis and segmental lordosis were decreased at the final follow-up as compared to preoperative lordosis.

Lumbar lordosis after lumbar disc replacement / 中国组织工程研究

BACKGROUND:Artificial total disc replacement is one treatment of low back pain in recent years, but the report on the effect of disc replacement on lumbar sagittal plane is rare. OBJECTIVE:To analyze the effect of lumbar disc replacement on lumbar lordosis. METHODS:Retrospective analysis of radiographic data of 17 patients who underwent lumbar disc replacement for single segment degenerative disc disease was carried out. Data measurement included preoperative and postoperative lumbar lordosis, diseased segmental lordosis and lumbar intervertebral angle. RESULTS AND CONCLUSION:Al the 17 patients were fol owed-up for more than 12 months. Lumbar disc replacement was performed at L4-5 segment in three cases and L5-S1 segment in 14 cases. The average diseased segmental lordosis and lumbar lordosis were increased significantly after replacement when compared with those before replacement (P<0.05);the lumbar intervertebral angle was increased after replacement when compared with that before replacement, but the difference was not significant. The results indicate that lumbar disc replacement for the treatment of single segment degenerative disc disease can increase the lumbar lordosis and diseased segmental lordosis, which can help to improve the lumbar sagittal balance. The postoperative lumbar intervertebral angle has no correlation with the implant angle of the prosthesis on the replace segment.

A Comparison Study on the Change in Lumbar Lordosis When Standing, Sitting on a Chair, and Sitting on the Floor in Normal Individuals

OBJECTIVE: To compare radiographic analysis on the sagittal lumbar curve when standing, sitting on a chair, and sitting on the floor. METHODS: Thirty asymptomatic volunteers without a history of spinal pathology were recruited. The study population comprised 11 women and 19 men with a mean age of 29.8 years. An independent observer assessed whole lumbar lordosis (WL) and segmental lordosis (SL) between L1 and S1 using the Cobb's angle on lateral radiographs of the lumbar spine obtained from normal individuals when standing, sitting on a chair, and sitting on the floor. WL and SL at each segment were compared for each position. RESULTS: WL when sitting on the floor was reduced by 72.9% than the average of that in the standing position. Of the total decrease in WL, 78% occurred between L4 to S1. There were significant decreases in SL at all lumbar spinal levels, except L1-2, when sitting on the floor as compared to when standing and sitting on a chair. Changes in WL between the positions when sitting on a chair and when sitting on the floor were mostly contributed by the loss of SL at the L4-5 and L5-S1 levels. CONCLUSION: When sitting on the floor, WL is relatively low; this is mostly because of decreasing lordosis at the L4-5 and L5-S1 levels. In the case of lower lumbar fusion, hyperflexion is expected at the adjacent segment when sitting on the floor. To avoid this, sitting with a lordotic lumbar curve is important. Surgeons should remember to create sufficient lordosis when performing lower lumbar fusion surgery in patients with an oriental life style.

Radiographic Results of Single Level Transforaminal Lumbar Interbody Fusion in Degenerative Lumbar Spine Disease: Focusing on Changes of Segmental Lordosis in Fusion Segment

BACKGROUND: To assess the radiographic results in patients who underwent transforaminal lumbar interbody fusion (TLIF), particularly the changes in segmental lordosis in the fusion segment, whole lumbar lordosis and disc height. METHODS: Twenty six cases of single-level TLIF in degenerative lumbar diseases were analyzed. The changes in segmental lordosis, whole lumbar lordosis, and disc height were evaluated before surgery, after surgery and at the final follow-up. RESULTS: The segmental lordosis increased significantly after surgery but decreased at the final follow-up. Compared to the preoperative values, the segmental lordosis did not change significantly at the final follow-up. Whole lumbar lordosis at the final follow-up was significantly higher than the preoperative values. The disc height was significantly higher in after surgery than before surgery (p = 0.000) and the disc height alter surgery and at the final follow-up was similar. CONCLUSIONS: When performing TLIF, careful surgical techniques and attention are needed to restore and maintain the segmental lordosis at the fusion level.

The Changes of Adjacent Segments after Long Segment Posterolateral Fusion: Comparative Study of 3 year versus over the 7 year Follow-up Patients / 대한정형외과학회잡지

PURPOSE: To compare the 3 year and over the 7 year results after long-segment posterolateral fusion and to analyze the changes of adjacent segments and the changes according to the segmental lordosis angle of the fusion segments. MATERIALS AND METHODS: A retrospective review was carried out 62 patients of long segment fusion for 7 years follow up and compared that of the 3 year and over the 7 year results. The changes of adjacent segments were evaluated by simple radiography for disc space narrowing, traction spur, endplate sclerosis and vacuum phenomenon.In last follow-up, segmental lordosis angle of fusion level was evaluated by Gelb's criteria and clinical results were analyzed by Katz's classification. RESULTS: In the changes of adjacent segments, disc space narrowing was increased 27.4% to 38.7%, traction spur was 22.6% to 35.5%, endplate sclerosis was 19.4% to 32.2% and vacuum phenomenon was 8.1% to 12.9%. The changes of adjacent segments were observed that from 3.4% to 20.7% in physiologic group and from 33.3% to 90.9% in un-physiologic group. The clinical results showed 83.9% satisfaction and 16.1% un-satisfaction. CONCLUSION: In long-term follow up of long-segment posterolateral fusion, physiologic segmental lordosis angle should be preserved for decrease of changes of adjacent segments in long-segment posterolateral fusion.

Factors Affecting Segmental Lordotic Angle After Posterior Lumbar Interbody Fusion Using Metal Cage / 대한척추외과학회지

STUDY DESIGN: This is a retrospective study. OBJECTIVES: We tried to find out what kind of factors affect the segmental lordotic angle improvement after performing posterior lumbar interbody (PLIF) fusion using a metal cage. The study was done using radiographic measurements. SUMMARY OF LITERATURE REVIEW: For degenerative spinal disease, PLIF with using a metal cage is an effective way to fuse and restore segmental lordosis of the lumbar spine. MATERIALS AND METHODS: The study included 104 patients (65 males, 39 females). Radiographs of the antero-posterior, lateral, flexion and extension views that were taken during the preoperative period and the follow-up 6 months were evaluated for the L4-5 segmental lordosis angle, cage invagination, cage position and disc height. Then, statistical analysis was performed using the Pearson method to determine which factors affected the segmental lordotic angle correction. RESULTS: The increase of the anterior disc height on the postoperative lateral radiograph (gamma=0.303, p<0.01) and the increase of lordosis on the preoperative extension radiograph (gamma=0.384, p<0.01) showed statistically positive correlation with the increase of the postoperative segmental lordosis angle. When comparing between the 4 degrees and 8 degrees cages, the more angle the cage had, the more segmental angle was restored and this was statistically correlated (P<0.05). However, the amount of segmental lordosis angle correction was not as much as the angle of the cage that was used. Other factors such as cage invagination and cage position didn't show statistical correlation. CONCLUSIONS: Posterior lumbar interbody fusion using a metal cage is useful method for restoring the lumbar segmental lordosis angle only if the disc is flexible enough to be distracted (ED note: distracted is the word you want?) sufficiently intraoperatively or if it allows good segmental lordosis, as seen on the preoperative extension radiograph. Correction of the segmental lordosis angle using a wedged cage with a larger angle was not always satisfactory because it did not restore as much angle as the angle of cage that was used.

Prognostic Factors of the Posterior Lumbar Interbody Fusion with Expandable Cage

OBJECTIVE: The authors performed lumbar arthrodesis with expandable cage at L3-4 to L5-S1 intervertebral space for one year and report the analysis of the factors influencing the successful results. METHODS: The authors included thirty-five patients whose bony fusion had been watched over the 12 month after a posterior interbody fusion procedure with one-level expandable cage. All patients were classified into group A(satisfactory results) and group B(unsatisfactory results) according to their answers to comprehensive low back questionnairies. The intervertebral disc height, segmental lordosis and total lumbar lordosis in the standing neutral lateral radiography were checked and the comparison in the changes of this radiological profiles before and after the surgery was done. RESULTS: Seventeen cases(48.6%) of "excellent" results, and 14 cases(40.0%) of "good" results were included in Group A. In group B, 2 cases(5.7%) of "fair" results and 2 cases(5.7%) of "poor" results were included. Over twelve months after the operation, the mean intervertebral disc height and segmental lordotic angle in group A significantly increased, but those in group B did not significantly increase; however, the improvement of total lumbar lordotic angle could not be observed on both groups. CONCLUSION: The results indicate that the recovery of both intervertebral disc height and segmental lordosis is absolutely essential in order to get a successful result in addition to the solid arthrodesis. However, significant influences of one-level segmental lordotic improvement on the total lumbar lordosis can not be observed after the expandable cage fusion in the lower lumbar spine.