Optical coherence tomography features and correlation of functional and structural parameters in patients of idiopathic intracranial hypertension

Purpose: To determine the correlation between functional parameters and optical coherence tomography (OCT) features in patients of idiopathic intracranial hypertension (IIH). Methods: A prospective observational study in early and established cases of papilledema in IIH presenting from December 2017 to February 2019. Functional parameters (visual acuity, contrast sensitivity, mean deviation, VER, and MfERG) and structural parameters (RNFL, GCL?IPL, and optic disc height) were measured at baseline and every 6 weeks for 6 months. Results: At baseline, average RNFL had a moderate negative correlation with mean deviation (r = ?0.45; P = 0.0007) and a positive correlation with logMAR visual acuity (r = 0.18; P = 0.17). On the contrary, baseline GCL and logMAR visual acuity had a negative correlation (r = ?0.4, P = 0.02). Optic disc height (ODH) had a negative correlation with visual field mean deviation (r = ?0.046; P = 0.0005). At 6 months, ODH and GCL?IPL complex had a statistically significant correlation with functional parameters. However, RNFL values did not show any significant correlation with any of the functional parameters. Baseline GCL?IPL and optic disc height values had a moderate and significant correlation with final functional parameters. However, RNFL did not show any correlation with final functional parameters. Correlation between GCL?IPL thickness at 6 weeks and final functional parameters were stronger than that with baseline GCL values. Conclusion: In the setting of severe papilledema, RNFL can misguide the prognosis. GCL?IPL can be a valuable tool for an objective evaluation of the integrity of the optic nerve in IIH and ODH may be used as an alternative or in combination with GCL?IPL in these cases.

Construction and Evaluation for Model of Goat Intervertebral Disc Degeneration Induced by Axial Compressive Stress / 医用生物力学

Objective To establish the model of goat intervertebral disc degeneration （IDD） induced by controllable axial compressive stress and evaluate its imaging and pathological characteristics. Methods Twenty goats were randomly divided into 4 groups (control group, 4-week pressure group, 8-week pressure group, 12-week pressure group, n=5, 40 N pressure). Disc height index (DHI) was used to evaluate the change of intervertebral disc height by X-ray, Pfirrmann classification method was used to observe the degree of intervertebral disc degeneration by magnetic resonance imaging (MRI), and histopathological observation and evaluation for intervertebral disc were conducted by HE staining and immunohistochemistry. Results DHI in control group showed no significant changes with the extension of pressure time, while DHI in the experimental group gradually decreased. There was no significant change in Pfirrmann classification in control group. In experimental group, with the extension of time, the higher the degeneration aggravated with the Pfirrmann classification increasing. In experimental group, HE staining showed that the disc nucleus pulposus decreased in volume and nucleus pulposus cells, which were gradually replaced by fibrous tissues. Immunohistochemical staining showed that type I collagen in the nucleus pulposus gradually increased, type Ⅱ collagen gradually decreased, and intervertebral disc degeneration occurred. Conclusions A certain axial compressive stress can lead to degeneration of goat lumbar intervertebral disc, and the degree of degeneration is gradually increased with the extension of time.

Changes in Sagittal Alignment Following Short-Level Lumbar Interbody Fusion: Comparison between Posterior and Lateral Lumbar Interbody Fusions

STUDY DESIGN: Retrospective case-control study.PURPOSE: We aimed to compare radiologic outcomes between posterior (PLIF) and lateral lumbar interbody fusion (LLIF) in short-level spinal fusion surgeries.OVERVIEW OF LITERATURE: Although LLIF enables surgeons to insert large lordotic cages, it is unknown whether LLIF more effectively corrects local and global sagittal alignments compared with PLIF in short-level spinal fusion surgeries.METHODS: Radiographic data acquired from patients with lumbar interbody fusion (≤3 levels) using PLIF or LLIF for degenerative lumbar diseases were analyzed. The following radiographic parameters were evaluated preoperatively and at 2 years postoperatively: segmental lordotic angle, disk height, lumbar lordosis (LL), pelvic tilt (PT), C7 sagittal vertical axis, and thoracic kyphosis (TK).RESULTS: In total, 144 patients with PLIF (193 fused levels) and 101 with LLIF (159 fused levels) were included. Patients’ backgrounds and preoperative radiographic parameters for any level of fusion did not differ significantly between PLIF and LLIF procedures. The LLIF group exhibited significantly greater changes at 1-level fusion compared to the PLIF group in the parameters of segmental lordotic angle (5.1°±5.8° vs. 2.1°±5.0°, p<0.001), disk height (4.2±2.3 mm vs. 2.2±2.0 mm, p<0.001), LL (7.8°±7.6° vs. 3.9°±8.6°, p=0.004), and PI–LL (−6.9°±6.8° vs. −3.6°±10.1°, p=0.03). While, a similar trend was observed regarding 2-level fusion, significantly greater changes were only observed in LL (12.1°±11.1° vs. 4.2°±9.1°, p=0.047) and PI–LL (−11.2°±11.3° vs. −3.0°±9.3°, p=0.043), PT (−6.4°±4.9° vs. −2.5°±5.3°, p=0.049) and TK (7.8°±11.8° vs. −0.3°±9.7°, p=0.047) in the LLIF group at 3-level fusion.CONCLUSIONS: LLIF provides significantly better local sagittal alignment than PLIF in 1- or 2-level fusion cases and improves spinopelvic alignment and local alignment for 3-level fusion cases. Thus, LLIF was demonstrated to be a useful lumbar interbody fusion technique, constituting a powerful tool for achieving sagittal realignment with minimal surgical invasiveness.

Loss of Disc Height after Spontaneous Regression of a Herniated Lumbar Disc: A Case Report

STUDY DESIGN: Case report. OBJECTIVES: We report 3 cases of loss of disc height after spontaneous regression of a herniated lumbar disc. SUMMARY OF LITERATURE REVIEW: Reports of spontaneous regression of a herniated lumbar disc were identified. MATERIALS AND METHODS: We conservatively treated 3 patients who were diagnosed with a herniated lumbar disc. During outpatient follow-up, radiating pain improved in all patients, but they complained of chronic lower back pain. Magnetic resonance imaging (MRI) was performed for diagnostic purposes. RESULTS: On MRI, spontaneous regression of the herniated lumbar discs was observed, but loss of disc height was also found. CONCLUSIONS: A herniated lumbar disc may be a risk factor for loss of disc height. It is important to recognize that a patient with a herniated lumbar disc can struggle with chronic lower back pain even if spontaneous regression of the herniated lumbar disc occurs.

X-ray measurement of anatomical, natural and pathological heights of cervical intervertebral disc and its clinical significance / 第二军医大学学报

Objective To propose the three heights of intervertebral disc during cervical disc degeneration by measuring the cervical intervertebral disc heights in patients with cervical spondylosis. Methods Totally 96 patients with cervical spondylosis undergoing surgery in our hospital from Jan. 2017 to May 2017 were enrolled in this study, and their intervertebral disc heights of C2-7 were measured by the lateral X-ray. The patients were divided into 3 groups according to the Pfirrmann score: anatomical height group (Pfirrmann score-Ⅱ grade without height loss), natural height group (Pfirrmann score III grade), and pathological height group (Pfirrmann score -grade with moderate and severe intervertebral height loss). Two-way ANOVA and LSD analysis were performed to compare the intervertebral disc heights between the three groups. Results The average age of 96 patients was (53.4±19.6) years old, with 57 males and 39 females. Fifty-nine cases were diagnosed with cervical spondylotic myelopathy, 25 with nerve root type cervical spondylosis, and 12 with mixed cervical spondylosis. The average intervertebral disc heights in the anatomic height, natural height and pathological height groups were (7.7±1.2) mm, (7.1±0.9) mm and (5.9±1.0) mm, respectively, and there were significant differences between the three groups (all P<0.01). The cut-off values (sensitivity, specificity) of the anatomical heights and natural heights, natural heights and pathological heights of C3-4, C4-5, C5-6 and C6-7 were 7.45 mm (0.62, 0.65) and 6.95 mm (0.63, 1.00), 7.75 mm (0.49, 0.85) and 6.10 mm (0.89, 0.43), 7.75 mm (0.59, 0.77) and 6.95 mm (0.66, 0.91), and 7.85 mm (0.61, 0.89) and 5.95 mm (0.86, 0.73), respectively. Conclusion During the process of degeneration, cervical disc height can be classified as anatomical height, natural height (degenerative height) and pathological height. We should pay attention to the intervertebral disc height before operation and suggest to restore natural disc height.

Preservation of Motion at the Surgical Level after Minimally Invasive Posterior Cervical Foraminotomy

OBJECTIVE: Although minimally invasive posterior cervical foraminotomy (MI-PCF) is an established approach for motion preservation, the outcomes are variable among patients. The objective of this study was to identify significant factors that influence motion preservation after MI-PCF. METHODS: Forty-eight patients who had undergone MI-PCF between 2004 and 2012 on a total of 70 levels were studied. Cervical parameters measured using plain radiography included C2–7 plumb line, C2–7 Cobb angle, T1 slope, thoracic outlet angle, neck tilt, and disc height before and 24 months after surgery. The ratios of the remaining facet joints after MI-PCF were calculated postoperatively using computed tomography. Changes in the distance between interspinous processes (DISP) and the segmental angle (SA) before and after surgery were also measured. We determined successful motion preservation with changes in DISP of ≤3 mm and in SA of ≤2°. RESULTS: The differences in preoperative and postoperative DISP and SA after MI-PCF were 0.03±3.95 mm and 0.34±4.46°, respectively, fulfilling the criteria for successful motion preservation. However, the appropriate level of motion preservation is achieved in cases in which changes in preoperative and postoperative DISP and SA motions are 55.7 and 57.1%, respectively. Based on preoperative and postoperative DISP, patients were divided into three groups, and the characteristics of each group were compared. Among these, the only statistically significant factor in motion preservation was preoperative disc height (Pearson’s correlation coefficient=0.658, p<0.001). The optimal disc height for motion preservation in regard to DISP ranges from 4.18 to 7.08 mm. CONCLUSION: MI-PCF is a widely accepted approach for motion preservation, although desirable radiographic outcomes were only achieved in approximately half of the patients who had undergone the procedure. Since disc height appears to be a significant factor in motion preservation, surgeons should consider disc height before performing MI-PCF.

The effectiveness of seated combined extension-compression and transverse load traction in increasing cervical lordosis- challenging the underlying framework

Introduction: The goal of this study was to assess the effectiveness of seated combined extension- compression and transverse load (ECTL) traction as a new method for increasing a reduced lordosis of less than 30 degrees in a Malaysian population between the ages of 18 and 60 years. Possible changes in disc height were measured in accordance with the underlying theoretical framework, that suggests the anterior cervical structures would elongate due to creep over the fulcrum of the traction device. Method: This was a single centre, randomised, blinded controlled clinical trial with parallel groups, used to test the superiority of the seated combined ECTL traction together with physiotherapy exercises when compared with the same physiotherapy exercises used as a control. Fifty randomly allocated subjects who completed the forty treatments over the fourteen weeks were analysed using non-parametric tests for changes in outcomes. Results: There were no significant changes in outcomes for disc height changes seen in this study. The findings of a greater overall increase in posterior disc height changes compared with anterior disc height changes were in contrast with the proposed underlying theoretical framework for this type of ECTL traction. The greater height changes occurring in the control group were also unexpected. Conclusion: The findings in this study of the contrasting changes in disc height of greater posterior than anterior height changes, question the underlying theoretical framework as postulated for this type of traction.

Radiologic Changes of Operated and Adjacent Segments after Anterior Cervical Microforaminotomy

OBJECTIVE: Anterior cervical microforaminotomy (ACMF) is a motion-preserving surgical procedure. The purpose of this study is to assess radiologic changes of operated and adjacent segments after ACMF. METHODS: We retrospectively reviewed 52 patients who underwent ACMF between 1998 and 2008. From X-ray film-based changes, disc height and sagittal range of motion (ROM) of operated and adjacent segments were compared at preoperative and last follow-up periods. Radiological degeneration of both segments was analyzed as well. RESULTS: The mean follow-up period was 48.2 months. There were 78 operated, 52 upper adjacent, and 38 lower adjacent segments. There were statistically significant differences in the ROM and disc height of operated segment between preoperative and last follow-up periods. However, there were no statistically significant differences in the ROM and disc height of adjacent segment between both periods. Radiological degenerative changes of operated segments were observed in 30%. That of adjacent segments was observed in 11 and 11% at upper and lower segments, respectively. CONCLUSION: After mean 4-year follow-up periods, there were degenerative changes of operated segments. However, ACMF preserved motion and prevented degenerative changes of adjacent segments.

Extent of Disc Degeneration after Single-Level Cervical Anterior Microforaminotomy Analyzed with Long-Term Radiological Data

OBJECTIVE: To prove the extents and details of cervical degeneration after anterior microforaminotomy (AMF) with 6-years follow-up. METHODS: A retrospective study of 24 patients, underwent single-level AMF, was performed. Clinical and radiologic data were analyzed with office charts, questionaires, and picture achieving and communication system images. RESULTS: According to Odom's criteria, 91.6% achieved favorable outcome. The mean visual analog scale score was improved from 8.6 to 3, and the mean neck disability index was improved from 27.9 to 7.3 (p<0.01). Eighteen cases (75%) showed disc height (DH) decrease. The disc invasion was correlated with DH decrease (p<0.05). The disc height decrease correlated with static, dynamic changes of shell angle and spur formation (p<0.05). Any radiological parameters did not affect the clinical outcome. CONCLUSION: AMF is an effective technique for treating unilateral cervical radiculopathy. It showed excellent surgical outcomes even in long-term follow-ups. However, a decrease in DH occurred in a considerable number of patients. Disc invasion during surgery may be the trigger of sequential degeneration.

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.

Does the Size of Anterior Microforaminotomy Affect the Surgical Outcome? / 이화의대지

OBJECTIVES: Anterior microforaminotomy (AMF) is an alternative procedure to treat unilateral cervical pathology. Although the results have been reported favorable in the previous studies, postoperative degeneration may occur. We analyze long-term outcome to determine the critical size of AMF. METHODS: A retrospective study was performed. Clinical data with chart review, radiologic data with picture archiving and communication system (PACS) images were obtained. Long-term clinical outcomes were accessed by a questionnaire, including visual analogue scale (VAS) and neck disability index (NDI). Various clinical, radiological data were statistically analyzed. RESULTS: Eight-two patients were enrolled in this study. Main pathology was spondylotic spur (53.7%), soft disc herniation (36%). Mean age was 49 years old. There was no surgery-related complication. Mean follow-up was 6.1 years. 90.3% showed favorable clinical outcome. Mean VAS score was decreased from 8.2 to 2.9, and NDI score was decreased from 24.5 to 6.7 (P<0.05). 88.7% showed decrease of disc height (DH), and mean change was 1 mm. DH change was correlated positively with the disc invasion and AMF diameter (P<0.05). Mean diameter of AMF was 5.2 mm. According to statistical analysis, the critical diameter of AMF was 4.7 mm, directly affecting DH decrease. Any radiological parameters did not affect the clinical outcome. CONCLUSION: AMF was an effective procedure to treat unilateral cervical pathology. Critical DH decreases and/or disc invasion may be the trigger of sequential degeneration. To preserve DH, AMF diameter should be small and disc invasion should be avoided.

Factors Affecting Segmental Motion of Lumbar Total Disc Replacement / 대한정형외과학회잡지

PURPOSE: To assess factors significantly affecting the range of motion of the lumbar spine at the operated segment following total disc replacement (TDR) arthroplasty. MATERIALS AND METHODS: Thirty-six patients (15 men and 21 women) who received lumbar TDR at a single level using Prodisc II (Spine Solutions Inc, New York, NY USA) were included in this study. The study included 23 cases at L4-5 and 13 cases at L5-S1. The average patient age was 43.6 years (range, 23-59 years) and the minimum follow-up was 24 months (range, 24-61 months). Two independent observers measured radiological parameters preoperatively, at 3 months postoperatively, and at the final follow-up. These parameters included disc height, affected level segmental range of motion (ROM) and prosthesis position and height. A radiologist independently measured facet joint degeneration and the fat contents of the paraspinal muscles on preoperative MR images. Clinical results were evaluated using the Oswestry Disability Index (ODI) and the Visual Analogue Scale (VAS). RESULTS: Segmental ROM was well preserved at the final follow-up (preoperative, 11.3 degrees; 3 months postoperative 13.2 degrees; final follow up, 13.1 degrees). The factors found to affect segmental ROM significantly at the final follow-up were the preoperative ROM, preoperative disc height, disc height increment ratio and a history of previous back surgery on the affected disc (p<0.05). The VAS significantly improved in patients with increased segmental ROM at the operated level (p<0.05). CONCLUSION: Statistical analysis showed that the factors affecting segmental ROM were the preoperative ROM, preoperative disc height, disc height increment ratio, and a history of previous back surgery on the affected disc. However, further effort needs to be directed towards an evaluation of a larger number of patients with a longer follow-up.

Effects of Decompression Therapy for the Treatment of a Herniated Lumbar Disc / 대한통증학회지

BACKGROUND: Traction has often been utilized to treat patients with a herniated lumbar disc. Currently, the most advanced type of traction therapy is non-surgical spinal decompression. Therefore, this study was conducted to evaluate the effectiveness of decompression therapy in patients with a herniated lumbar disc based on clinical findings and symptoms. METHODS: Sixty patients with herniated lumbar discs were included in this study. The patients were randomly divided into two groups, a decompression group (n = 30) and a traction group (n = 30). To evaluate the impact of decompression and traction therapy on the herniated disc, the clinical symptoms for each group were evaluated prior to and after treatment using the visual analogue scale (VAS), straight leg raising (SLR), the herniation index, and the disc height. RESULTS: The VAS score was significantly lower in the decompression group (2.0 +/- 0.2) than the traction group (3.9 +/- 0.2) following treatment. In addition, the SLR angle was significantly higher in the decompression group (79 +/- 1.5) than the traction group (63.3 +/- 1.9). The herniation index was significantly lower in the decompression group (217.6 +/- 19.1) than the traction group (259.5 +/- 16.4). Finally, the disc height was not significant differences between pre-treatment and follow-up in two groups. CONCLUSIONS: The results of this study suggest that decompression therapy for the treatment of patients suffering from a herniated lumbar disc has an effect on the pain, SLR, and herniation indices, not disc heights.

The Correlation Between Radiographic and Clinical Results after Anterior Cervical Discectomy and Fusion / 대한척추외과학회지

STUDY DESIGN: This is a prospective study. OBJECTIVES: We wanted to analyse the correlation between the radiographic and clinical results after anterior cervical discectomy and fusion (ACDF) for treating degenerative cervical diseases. Summary of Literature REVIEW: ACDF is a successful procedure for treating the degenerative cervical spine. Many studies have reported on radiographic results and clinical outcomes of this procedure. However, few studies have examined the relationships between the changes of the radiographic parameters and the clinical results after ACDF. MATERIALS AND METHODS: 26 patients who had single level ACDF performed for degenerative cervical diseases during the period between Jan, 2000 and Dec, 2004 were evaluated. All the patients underwent autologous iliac bone graft and plate fixation. The radiographic parameters, including the disc height, the disc space angulation and the spinous process distance were measured at the preoperative period, post operative 1 month and the last follow up period, respectively. The clinical changes were measured using the visual analogue scale (VAS) for neck and arm pain at the preoperative and last follow up period. The correlations between the radiographic parameters and the clinical outcomes were assessed by Pearson correlation. RESULTS: There were significant changes in disc height (6.7-7.9 mm) as well as disc space angulation (kyphosis: 1.1degrees, lordosis: 3.4degrees). The reduction in the neck pain VAS score (63.9-33.1) and the arm pain VAS score (57.9-29.7) was significant. None of the correlations between the radiographic parameters and the clinical outcomes were significant (p>0.05). CONCLUSION: Although the clinical outcomes improved significantly, there was no significant correlation between the radiographic parameters and clinical results after performing single level anterior cervical discectomy and fusion for the degenerative cervical disease.

Radiological and Clinical Analysis of Degenerative Lumbar Retrolisthesis: Comparative Study of Degenerative Spondylolisthesis / 대한척추외과학회지

STUDY DESIGN: This is a retrospective study. OBJECTIVES: We wanted to analyze the radiological features of degenerative lumbar spondylolisthesis and retrolisthesis, and we wanted to verify what radiological factors are related to the development of the retrolisthesis. We also wanted to determine these radiological factors' clinical significance. SUMMARY OF THE LITERATURE REVIEW: There is little information about the pathological mechanism and the clinical and radiological aspects of degenerative lumbar retrolisthsis. MATERIALS & METHODS: Sixty patients were reviewed and divided into three groups. The degenerative lumbar retrolisthesis patients were in group A. The degenerative lumbar spondylolisthesis patients were in group B. Group C patients had no vertebral shift in any direction. The factors we measured were the facet joint angle, the disc height of L3-4, L4-5 and L5-S1, and the lordosis of the lumbar spine. The evaluation of the clinical results was then quantified. RESULTS: The facet joint angle showed no statistical significance between the two groups. The disc height of group A at L4-5 and L5-S1 was more decreased in group A than in group B (p<0.05). Lumbar lordosis was decreased significantly in group A (p<0.05). The preoperative pain was improved at the final follow up, but preoperative pain was significantly higher in group A than in group B (p<0.05). The clinical results were improved in each group, but there was no statistically significant difference between the two groups. CONCLUSIONS: The disc height and lumbar lordosis were considerably reduced in the patients with retrolisthesis, especially compared to those patients with spondylolisthesis. Preoperative pain was higher for the retrolisthesis patients than for the spondylolithesis patients, but there was no significant difference.

The Changes of Disc Height and Degeneration in Patients with Lumbar Disc Herniation / 대한척추외과학회지

STUDY DESIGN: The changes of the disc height in patients diagnosed with lumbar disc herniation who underwent a discectomy were subjected to a retrospective study. OBJECTIVES: The goal of this study was to find the relationship between the disc height and degenerative disc changes in patients diagnosed with lumbar disc herniation who underwent a discectomy. SUMMARY OF LITERATURE REVIEW: Disc height changes according to age, degenerative change and the amount of removed disc. MATERIALS AND METHODS: The patients in this study were those diagnosed with HNP who undergone a discectomy in our hospital. The fifty seven observed patients had a discectomy in our hospital between March, 2001 and March, 2003. Patients who had posterior fusion during surgery were excluded. There were 35 males and 22 females, with an average age of 35.9 yrs old (17-55) and a mean follow-up period of 2.7 yrs. The degrees of HNP and degenerative disc were examined with MRI and measured through the T2 MRI, respectively, before the operation. The disc heights were measured before and after surgery, and the anterior, posterior and middle disc heights were measured with a simple lumbar lateral X-ray. There were 6, 20, 25 and 6 cases of degeneration grades II, III, IV and V, respectively. There were also 27, 25 and 5 cases of protruded, extruded and sequestrated discs, respectively. RESULTS: When patients with a lumbar disc herniation underwent a discectomy, the changes of disc height in people of those with a postoperative degenerative disc change were notable, but there was no difference in disc height change with regard to the degree of HNP. CONCLUSION: In lumbar disc herniation patients after a discectomy, the changes of disc height decrease significantly in severe degenerative discs in the short term; therefore, further long term periods of study will be required.

Short-term Results of Anterior Cervical Fusion with Cylindrical Cage(AMSLU(TM))

OBJECTIVE: The AMSLU(TM) cage is a newly developed instrument, that utilizes concept of the key-stone graft in posterior lumbar interbody fusion. The authors try to prove the short-term efficacy of AMSLU(TM) cage in surgical treatment of degenerative cervical disc disease. METHODS: We investigate clinical and radiological features of 24 patients who underwent anterior cervical fusion with AMSLU(TM) cage during the period between January 2001 and February 2002. Clinical and radiological results were assessed by using Odom's criteria and regular follow-up of radiographs, respectively. RESULTS: All patients included in this study had been followed by at least 6 months. Except 3 patients, all patients underwent single-level operation, and among remaining 21 patients, C5-6 was the most commonly involved level (17 cases). Symptomatic improvement was found in 22 cases (91%). Evidence of bone fusion was invariably found by the end of the postoperative 6 months in every case and increase of disc height was also shown in all patients. Neither operation-related nor instrument-related complications was seen. CONCLUSION: Anterior cervical fusion with AMSLU(TM) cage has several advantages over the preexisting instruments, such as easy maneurability, avoidance of donor site complications, and anatomical contour which renders it to endure lateral shearing force and its relatively large contact area.

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.

The Relationship between Radiologic Parameters of Lumbar Spine and Occurrence of Low Back Pain in High Risk Workers

OBJECTIVE: To investigate the relationship between commonly used radiologic parameters and occurrence of low back pain (LBP) through prospective study using pre-employment radiologic examination in high risk workplace. METHOD: One hundred and fifty four male workers in high risk workplace were evaluated. Lumbar lordosis, lumbosacral angle, lumbar gravity line and lumbar disc height-related parameters were measured using simple radiologic films of lateral lumbosacral view taken during pre-employment medical check. Relationship between occurrence of LBP during post-employment period with a mean 1.7+/-1.0 years and radiologic parameter was investigated. RESULTS: Lumbar lordosis, lumbosacral angle and lumbar disc height were not significantly correlated to the occurrence of LBP. Amount of anterior shift of lumbar gravity line did not showed correlation to occurrence of LBP, but subjects with posterior displacement of lumbar gravity line showed significantly low rate of occurrence of LBP. CONCLUSION: These results suggest that commonly used radiologic parameters are not so useful to predict occurrence of LBP in high risk workers. The possibile preventive effect of posterior shift of lumbar gravity line seems to be worth further researching.

Diurnal Fluid Change in Lumbar Discs and Vertebral Marrow with MRI Signal Intensity

No reports in the recorded literature have indicated diurnal variations in MRI of the intervertebral disc and marrow at the different portions of each disc and vertebral body. Eight healthy asymptomatic 8 healthy volunteers between 23 and 29 years old under-went twice-daily MRI of their lumbar spine(AM, PM). forty lumbar discs were studied and the change in signal intensity was measured at three portions of each disc(a total of 120 portions: "a", "b"; middle, and "c"; posterior portion) and vertebral marrow adjacent to each end plate(a total of 240 portions). No visible changes between scans could be detected by blind observers. Calculated signal intensity changes, however, showed an average loss of 20%, 19% and 17.5% at the anterior, middle, and posterior portion, respectively. Signal intensity change at"a"portion was more pronounced at the L2-3 level, at "b"portion at the L4-5, and at"c"portion at the L1-2. Height loss of the disc was on an average 9.9%(anterior), 8.3%(middle), and 10.4% (posterior), but at all portions, was most pronounced at L3-4 level. Signal intensity in the vertebral marrow showed an average increase of 7.8%(anterior), 9.4%(middle) and 9.8%(posterior), the change was most pronounced at the lower, posterior portion, and around the L5 vertebral body. The degree of signal intensity change in the disc did not necessarily correlate with the degree of disc height loss(ant./post.: p<0.42) and marrow signal change(ant.: p<0.15, post.: p<0.18) at two portions of each level. Only at the middle portion, did signal intensity change correlate with disc height loss(p<0.008) and marrow change(p<0.0061). Our conclusions were as follows: 1) there is a diurnal variation in the fluid content of the disc and vertebral marrow; 2) the height of the discs and the change in signal intensity of the disc and marrow tended to be more pronounced from the anterior to posterior portion on moving down to the lower levels; 3) loss of disc height was most severe at L3-4.