Effect Of Spinal Fusion Research Articles

Hip loading asymmetry in Lenke type 1 idiopathic scoliosis: Effect of spinal fusion and sex

BackgroundThoracic curvatures are most common in patients with idiopathic scoliosis. The literature highlights an imbalance of hip joint moments in the frontal plane quantified with a symmetry index. Spinal arthrodesis can reduce this symmetry index which then tends towards 0. Furthermore, asymptomatic women present lower hip moment in the frontal plane than asymptomatic men. This difference could influence the symmetry index in the case of patients with idiopathic scoliosis. Therefore, the main objective of this study was to show a significant positive effect of spinal arthrodesis on the symmetry index. The secondary objective was to compare the symmetry index between sexes before spinal fusion. MethodThe retrospective study included 20 patients with Type-1 Lenke curve idiopathic scoliosis, who performed a gait analysis before and one year after spinal fusion. The gait analysis consisted of walking back and forth at spontaneous speed. FindingsWhile significantly lower curvatures were depicted, the symmetry index showed a significantly lower value after spinal fusion (p < 0.03). The symmetry index showed no significant difference between sexes (p > 0.05). InterpretationThe study shows the effect of surgical fusion on the symmetry index, although the latter remains significant compared to the norm. Literature reveals that spinal fusion tends to the symmetrisation of the body's center of mass and increases ranges of motion on the trunk and pelvis. This could favour symmetry of hip moment in the frontal plane. Future research should investigate other Type Lenke curves before and after surgery, and the effect of braces on this symmetry index.

Lumbar Spine Fusion and Symptoms of Leg Length Discrepancy After Hip Arthroplasty

BackgroundHip length discrepancy (HLD) is common after total hip arthroplasty (THA); however, the effect of spinal fusion on perceived leg length discrepancy (LLD) symptoms after THA has not been examined. This study tested the hypothesis that LLD symptoms are increased in patients who underwent lumbar spinal fusion and THA, compared with patients with THA only. MethodsThis retrospective cohort study included 67 patients who underwent lumbar spinal fusion and THA, along with 78 matched control patients who underwent THA only. Hip and spine measurements were taken on postoperative, standing anterior-posterior pelvic, lateral lumbar, and anterior-posterior lumbar spinal radiographs. Perceived LLD symptoms were assessed via telephone survey. ResultsBetween the spinal fusion and control groups, there was no significant difference in HLD (M = 7.10 mm, SE = 0.70 and M = 5.60 mm, SE = 0.49) (P = .403). The spinal fusion patients reported more frequently noticing a difference in the length of their legs than the control group (P = .046) and reported limping “all the time” compared with the control group (P = .001). Among all patients with an HLD ≤10 mm, those in the spinal fusion group reported limping at a higher frequency than patients in the control group (P = .008). Patients in the spinal fusion group were also more likely to report worsened back pain after THA (P = .011) than the control group. ConclusionFrequencies of a perceived LLD, limping, and worsened back pain after THA were increased in patients with THA and a spinal fusion compared with patients who had THA only, even in a population with HLD traditionally considered to be subclinical. The results indicate that in patients with prior spinal fusion, precautions should be taken to avoid even minor LLD in the setting of THA.

Residual lumbar hyperlordosis is associated with worsened hip status 5 years after scoliosis correction in non-ambulant patients with cerebral palsy.

Cerebral palsy (CP) is a static encephalopathy with progressive musculoskeletal pathology. Non-ambulant children (GMFCS IV and V) with CP have high rates of spastic hip disease and neuromuscular scoliosis. The effect of spinal fusion and spinal deformity on hip dislocation following total hip arthroplasty has been well studied, however in CP this remains largely unknown. This study aimed to identify factors associated with worsening postoperative hip status (WHS) following corrective spinal fusion in children with GMFCS IV and V CP. Retrospective review of GMFSC IV and V CP patients in a prospective multicenter database undergoing spinal fusion, with 5years follow-up. WHS was determined by permutations of baseline (BL), 1year, 2years, and 5years hip status and defined by a change from an enlocated hip at BL that became subluxated, dislocated or resected post-op, or a subluxated hip that became dislocated or resected. Hip status was analyzed against patient demographics, hip position, surgical variables, and coronal and sagittal spinal alignment parameters. Cutoff values for parameters at which the relationship with hip status was significant was determined using receiver operating characteristic curves. Logistic regression determined odds ratios for predictors of WHS. Eighty four patients were included. 37 (44%) had WHS postoperatively. ROC analysis and logistic regression demonstrated that the only spinopelvic alignment parameter that significantly correlated with WHS was lumbar hyperlordosis (T12-L5) > 60° (p = 0.028), OR = 2.77 (CI 1.10-6.94). All patients showed an increase in pre-to-postop LL. Change in LL pre-to-postop was no different between groups (p = 0.318), however the WHS group was more lordotic at BL and postop (pre44°/post58° vs pre32°/post51° in the no change group). Age, sex, Risser, hip position, levels fused, coronal parameters, global sagittal alignment (SVA), thoracic kyphosis, and reoperation were not associated with WHS. Postoperative hyperlordosis(> 60°) is a risk factor for WHS at 5years after spinal fusion in non-ambulant CP patients. WHS likely relates to anterior pelvic tilt and functional acetabular retroversion due to hyperlordosis, as well as loss of protective lumbopelvic motion causing anterior femoracetabular impingement. III.

Adolescent idiopathic scoliosis: evaluating perioperative back pain through a simultaneous morphological and biomechanical approach

BackgroundAdolescent idiopathic scoliosis (AIS) has been associated with diminished postural stability and a greater prevalence of back pain. Currently, the literature is lacking information on the effect of spinal fusion on both postural stability and its association with back pain. Our objectives were to evaluate the postsurgical effect of spinal morphological changes on static standing balance and assess the influence of these alterations on reported pain throughout the perioperative period.MethodsTwenty consecutive AIS patients schedule to undergo spinal fusion surgery were recruited and followed prospectively at the Shriners Hospitals for Children-Canada. Data was collected at the preoperative, 6 weeks and 6 months postoperative visits. Spinal morphology data was collected through 3D reconstructed simultaneous standing biplanar radiographs using the SterEOS software. Postural balance was assessed through Moticon© sensor insoles and analyzed through their software. The data was simultaneously collected as part of the Global Biomechanical and morphological Assessment. Pain was evaluated through self-reported questionnaires.ResultsMorphological curve parameters were significantly reduced after surgery. Balance parameters did not change significantly throughout the perioperative period with the exception of the Center of Pressure of the left foot medial/lateral transient shift (P = 0.017) at 6 weeks. Of note, preoperative balance parameters were associated with the degree of right thoracic Cobb angles (P = 0.029 R = 0.528). Pain scores significantly improved 6 weeks and 6 months after the surgery. Pain intensity diminished in the thoracic and lumbar spine but worsen in the neck region at the 6 weeks and 6 months postoperative time points (P = 0.044). Greater residual Cobb angle difference between Mid thoracic and Thoracolumbar/Lumbar curves was associated with greater pain severity at 6 weeks postop (P < 0.005). In addition, greater residual thoracic deformity was associated with significant pain severity 6 months after surgery (P < 0.05).ConclusionsImproved spinal morphology of postsurgical AIS patients has no significant impact on their static standing balance. Suggesting that other factors apart from the spinal morphology may contribute to AIS patients’ balance during stance. Although balance did not influence pain severity, spinal morphology and its correction appear to have influenced the intensity and location of back pain.

Analysis of the Biomechanical Effects of Spinal Fusion to Adjacent Vertebral Segments of the Lumbar Spine using Multi Body Simulation

Analysis of the Biomechanical Effects of Spinal Fusion to Adjacent Vertebral Segments of the Lumbar Spine using Multi Body Simulation

GAIT DISORDERS IN PATIENTS WITH INSTRUMENTED NEUROMUSCULAR SCOLIOSIS

ABSTRACT Introduction: The effect of spinal fusion on gait in patients with neuromuscular scoliosis continues to be a controversial issue, especially in patients where the spinal fusion extends to the pelvis. Objective: To evaluate the effect of spinal instrumentation in these patients. Methods: We evaluated 34 patients in a retrospective study. The mean age at surgery was 14±3 years and only ambulatory patients who presented neuromuscular scoliosis and non-progressing neurogenic pathology were included. The patients were surgically treated by posterior spinal fusion with or without extension to the pelvis. Preoperative (PRE) and postoperative (POP) Rx were measured. Ambulatory potential was clinically examined in all the patients, and 10 patients were assessed by full-gait analysis. Results: The minimum POP follow-up was 2 years (2006-2016). Nine patients were instrumented to the pelvis when the obliquity was greater than 15°; the remaining patients were treated using the same fusion-level criteria as those applied for idiopathic scoliosis. All patients maintained their gait, with improvements in coronal and sagittal balance, transfers and sitting skills, physical appearance, and in some cases, gait speed. Conclusions: Spinal instrumentation in ambulatory patients with neuromuscular scoliosis, including procedures with extension to the pelvis, provides adequate correction and preserves ambulatory function. Level of evidence III; Retrospective case control study.

The Effects of Spinal Fusion on Lumbar Disc Degeneration in Patients with Adolescent Idiopathic Scoliosis: A Minimum 10-Year Follow-Up

Study designRetrospective study. ObjectivesThis study focused on patients with adolescent idiopathic scoliosis (AIS) who were followed up for more than 10 years, and assessed the influence of spinal balance on lumbar degenerative changes at distal unfused segments (DUS). Summary of Background DataPrevious studies suggested that longer fusion segments may result in higher rates of occurrence of disc degeneration (DD) at unfused segments adjacent to the distal fused area. However, there are no existing studies that correlate the degree of DD to the location of lower instrumented vertebra (LIV) and the amount of the residual lumbar curve during the follow-up period. MethodsRadiologic measurements were recorded at the time of surgery, immediately after surgery, and 10 years after surgery. The Pfirrmann grading scale was used to rate the MR images of these patients. The presence of vertebral DD was also used to classify patients into DD+ and DD− groups. Results93 patients with AIS participated in this study. The average age at the time of surgery was 15.2 years; the average follow-up time was 154 months. DD was found in 45 patients (48%) and L5/S1 was the most common (40%) location in those patients. The L1 group experienced DD at a frequency of 34%, whereas the frequency increased with lower LIV placement. There was a significant difference between DD+ and DD− in age at the time of operation, the L4 tilt (pre Op. and post. 10 years), and the number of mobile segments. ConclusionsDisc degeneration occurred in 48% of the patients at the time of postop. 10 years. Disc degeneration had a tendency to occur in patients with greater preoperative and postoperative 10 years L4 tilt angle and fewer mobile segments in the lower lumbar spine. Level of EvidenceLevel III.

Reduced Lateral Center of Mass Sway During Gait After AIS Fusion Surgery

The effects of spinal fusion on gait kinematics in AIS are poorly understood. Center of mass (COM) displacement during gait has been used as an indicator of gait efficiency with the least energy consumption when the COM travels in a straight line.

Dissecting the Effects of Spinal Fusion and Deformity Magnitude on Quality of Life in Patients With Adolescent Idiopathic Scoliosis

Dissecting the Effects of Spinal Fusion and Deformity Magnitude on Quality of Life in Patients With Adolescent Idiopathic Scoliosis

Histologic and Electrophysiological Changes of the Paraspinal Muscle After Spinal Fusion

Experimental study evaluated electrophysiological and histologic changes in the paraspinal muscle after spinal fusion. To determine the effect of posterior spinal fusion on paraspinal muscle by means of electrophysiological and histologic evaluation, using a rabbit model. Posterior lumbar spinal fusion is a common spinal surgery. Paraspinal muscular dysfunction is postulated to be due to injury inflicted by the surgery, either during exposure or from disuse of the fused segment. The effect of spinal fusion on paraspinal muscular function remains unclear. Thirty New Zealand white rabbits were divided into 2 groups: 2-level posterior spinal fusion with instrumentation (group F) and the sham control group (group S). Preoperative and follow-up electromyography tests, as well as histologic assessments, were performed in 6-month intervals. In group F, 14 of 15 surgeries resulted in a solid fusion, as judged by postmortem examination. In group S, the root mean square of electromyography did not present a significant difference at 6-month follow-up when compared with preoperative status (P > 0.05). At 6-month follow-up, group F presented a significantly lower root mean square in the fused region than in adjacent regions (P < 0.05). Group S did not demonstrate significant differences in the median frequency between the preoperative and postoperative periods (P < 0.05). Group F resulted in a significant decrease of median frequency in the fusion region. However, increases were observed in the adjacent caudal region and the cranial region. The histologic analysis demonstrated a significant reduction in muscle fiber size (P < 0.05) in the fusion region of group F, when compared with the preoperative status, whereas group S did not present any significant differences (P > 0.05). These results demonstrated that spinal fusion resulted in atrophy and reduced adjacent paraspinal muscle activity. Muscular activity was greater in the adjacent regions after spinal fusion, which may indicate muscle hypertrophy.

The effect of spinal fusion on the long-term outcome of idiopathic scoliosis

The effect of spinal fusion on the long-term outcome of idiopathic scoliosis

The effect of spinal fusion on the long-term outcome of idiopathic scoliosis. A case-control study.

We have investigated the effect of multisegmental spinal fusion on the long-term functional and radiological outcome in patients with scoliosis. We compared these patients both with those whose spine had not been fused, and with a control group. We studied 68 patients with idiopathic scoliosis (34 operative and 34 non-operative) who had been followed up for a minimum of five years after treatment. They were matched for age (mean 44 years) and Cobb angle (mean 54 degrees) at follow-up. An age- and gender-matched control group of 34 subjects was also recruited. All participants completed a questionnaire to assess spinal function and to grade the severity of back pain using a numerical rating scale. Radiographs of the spine were taken in the patients with scoliosis and lumbar degenerative changes were recorded. The spinal function scores for the patients with scoliosis who had had a fusion were similar to those who had not. Both scoliosis groups, however, had lower scores than the control group (p < 0.001). The frequency and severity of back pain were lower for patients with scoliosis and fusion than for those without, but higher for both scoliosis groups compared with the control group. Radiographs showed similar degenerative changes in both scoliosis groups.

The effect of spinal fusion on the long-term outcome of idiopathic scoliosis

We have investigated the effect of multisegmental spinal fusion on the long-term functional and radiological outcome in patients with scoliosis. We compared these patients both with those whose spine had not been fused, and with a control group. We studied 68 patients with idiopathic scoliosis (34 operative and 34 non-operative) who had been followed up for a minimum of five years after treatment. They were matched for age (mean 44 years) and Cobb angle (mean 54°) at follow-up. An age- and gender-matched control group of 34 subjects was also recruited. All participants completed a questionnaire to assess spinal function and to grade the severity of back pain using a numerical rating scale. Radiographs of the spine were taken in the patients with scoliosis and lumbar degenerative changes were recorded. The spinal function scores for the patients with scoliosis who had had a fusion were similar to those who had not. Both scoliosis groups, however, had lower scores than the control group (p &lt; 0.001). The frequency and severity of back pain were lower for patients with scoliosis and fusion than for those without, but higher for both scoliosis groups compared with the control group. Radiographs showed similar degenerative changes in both scoliosis groups.

EFFECT OF INSTRUMENTED LUMBAR FUSION ON THE FLEXIBILITY AND VISCOELASTIC PROPERTIES OF THE ADJACENT SEGMENT: AN IN VIVO CANINE STUDY

The altered mechanical environment due to a rigid fixation is considered as the cause of degeneration at the adjacent levels. A canine in vivo study was performed to investigate the long-term effects of spinal fusion with instrumentation across the L5-sacrum on the flexibility and viscoelastic properties of the adjacent L4–5 disc. Five experimental dogs underwent a posterior fusion with Isola transpedicular instrumentation from L5 to sacrum and were euthanized 30 weeks postoperatively. A solid fusion was achieved across L5–L7 levels, but substantial motion persisted at the L7-sacrum segment. Biomechanical tests were performed to measure the flexibility and viscoelastic properties of the intervertebral disc above the instrumented spinal fusion in the experimental and nonoperated control groups. No statistically significant differences in the flexibility and viscoelastic responses of the adjacent L4–L5 segment were found between the control and experimental groups. Fusion of the L5–L7 segments did not significantly affect the flexibility and viscoelastic properties of the L4–5 disc at 30 weeks postoperatively in the mongrel dog spine.

Analysis of Lumbar Lordosis in Posterior Spine Fusions for Idiopathic Scoliosis

Previous reports are inconclusive regarding changes in the lumbar region after Harrington rod distraction and posterior spinal fusion for idiopathic scoliosis. The purpose of this study was to evaluate the effects of spinal fusion on the lumbar region, particularly the overall lumbar lordosis, the lumbar lordosis in and below the fused segment, the sacro-horizontal angle, and the sagittal plane alignment of the spine. Sixty-six patients under 21 years of age with idiopathic scoliosis who had spine fusion extending to the lumbar vertebrae using only Harrington distraction instrumentation were evaluated. The total lordosis, sacro-horizontal angle, and sagittal plane alignment remained relatively constant. The lordosis within the fusion decreased, and lordosis caudal to the fusion, including the last fused vertebra, increased as the lower hook placement site moved caudally.

Effects of spinal fusion on the proteoglycans of the canine intervertebral disc.

Posterior lumbar two-level spinal fusion was undertaken in 10 mature beagles. The animals were sacrificed 6 and 12 months later. Two months before sacrifice control and experimental animals received intravenously Na2(35)SO4 (1 mCi/kg). Discs encompassed by the fusion and those adjacent to it were dissected into the nucleus pulposus and annulus fibrosus (AF), which were analysed separately. Proteoglycans (PGs) were extracted with 4.0 M guanidine HCl and purified by CsCl density gradient ultracentrifugation. The hydrodynamic size and ability of the PG subunits to aggregate in the presence of hyaluronic acid were investigated by Sepharose CL-2B chromatography. The PG subunits were analysed for their galactosamine (galN), glucosamine (glcN), hexuronic acid, and protein content or were subjected to digestion with papain or chondroitin-ABC-lyase to establish the size of the chondroitin (CS) and keratan (KS) sulphate chains and the KS-PG core protein complex. Decreased ability to aggregate of PGs isolated from discs 6 and 12 months after surgery was demonstrated. While their hydrodynamic size after 6 months was generally the same or smaller than those in control tissues, the PG population present after 12 months was larger, particularly in the AF. Analysis of PG subunits from fusion discs afforded galN/glcN, galN/protein, and hexuronic acid/protein ratios that were compatible with the presence in these tissues of PGs in which the proportion of CS attached to core protein was greater than in control tissues. These studies provide the first experimental evidence that a metabolic response of discs in a fused segment may be accompanied by the biosynthesis of a new PG population whose structure is similar to that present in immature tissues.

The effect of spinal fusion on the collagen and proteoglycans of the canine intervertebral disc

The effects on disc composition of 16 months of lumbar spinal arthrodesis in the greyhound (a nonchondrodystrophoid breed) have been investigated using age-matched controls. The guanidinium chloride-extractable proteoglycans of the disc's nucleus pulposus and annulus fibrosus were compared using equilibrium density gradient ultracentrifugation under associative conditions. No differences in proteoglycan sedimentation behavior were detected between discs from experimental or control animals. Analysis of individual discs for collagen, total nitrogen, noncollagenous protein, uronic acid, or total hexosamine content also failed to demonstrate statistically significant differences between the experimental and control groups.

The effect of spinal fusion on intervertebral disc composition: An experimental study

Posterior fusions performed in immature beagles resulted in significant compositional changes of the discs encompassed by the fusion and those adjacent to it. By 6 months postoperation, a fall in collagen and a rise in noncollagenous protein content in the nucleus pulposus had taken place. Total nitrogen values were essentially unchanged. Although hexosamine levels were only minimally reduced as compared to control nuclear tissue, a significant alteration in the glucosamine and galactosamine distribution took place (after 6 months), both in the nucleus pulposus and the annulus fibrosus. In conjunction with uronic acid analysis, these changes are interpreted as a possible rise in the level of hyaluronic acid in the surgical and parasurgical discs. The significance of these findings is discussed in relation to the role of spinal fusion in the treatment of spinal disease and disorder.