Global Lumbar Lordosis Research Articles

Pelvic parameters of sagittal balance in extreme lateral interbody fusion for degenerative lumbar disc disease

There is increasing interest in the use of pelvic indices to evaluate sagittal balance and predict outcomes in patients with spinal disease. Conventional posterior lumbar fusion techniques may adversely affect lumbar lordosis and spinal balance. Minimally invasive fusion of the lumbar spine is rapidly becoming a mainstay of treatment of lumbar degenerative disc disease. To our knowledge there are no studies evaluating the effect of extreme lateral interbody fusion (XLIF) on pelvic indices. Hence, our aim was to study the effect of XLIF on pelvic indices related to sagittal balance, and report the results of a prospective longitudinal clinical study and retrospective radiographic analyses of patients undergoing XLIF in a single centre between January 2009 and July 2011. Clinical outcomes are reported for 30 patients and the retrospective analyses of radiographic data is reported for 22 of these patients to assess global and segmental lumbar lordosis and pelvic indices. Effect of XLIF on the correction of scoliotic deformity was assessed in 15 patients in this series. A significant improvement was seen in the visual analogue scale score, the Oswestry Disability Index and the Short Form-36 at 2months and 6months (p<0.0001). The mean pelvic index was 48.6°±11.9° (± standard deviation, SD) with corresponding mean sacral slopes and pelvic tilt of 32.0°±10.6° (SD) and 18.0°±9.5 (SD), respectively. XLIF did not significantly affect sacral slope or pelvic tilt (p>0.2). Global lumbar lordosis was not affected by XLIF (p>0.4). XLIF significantly increased segmental lumbar lordosis by 3.3° (p<0.0001) and significantly decreased the scoliotic Cobb angle by 5.9° (p=0.01). We found that XLIF improved scoliosis and segmental lordosis and was associated with significant clinical improvement in patients with lumbar degenerative disc disease. However, XLIF did not change overall lumbar lordosis or significantly alter pelvic indices associated with sagittal balance. Long-term follow-up with a larger cohort will be required to further evaluate the effects of XLIF on sagittal balance.

Radiographic measurement reliability of lumbar lordosis in ankylosing spondylitis

Intraobserver and interobserver reliabilities of the several different methods to measure lumbar lordosis have been reported. However, it has not been studied sofar in patients with ankylosing spondylitis (AS). We evaluated the inter and intraobserver reliabilities of six specific measures of global lumbar lordosis in patients with AS. Ninety-one consecutive patients with AS who met the most recently modified New York criteria were enrolled and underwent anteroposterior and lateral radiographs of whole spine. The radiographs were divided into non-ankylosis (no bony bridge in the lumbar spine), incomplete ankylosis (lumbar spines were partially connected by bony bridge) and complete ankylosis groups to evaluate the reliability of the Cobb L1-S1, Cobb L1-L5, centroid, posterior tangent L1-S1, posterior tangent L1-L5, and TRALL methods. The radiographs were composed of 39 non-ankylosis, 27 incomplete ankylosis and 25 complete ankylosis. Intra- and inter-class correlation coefficients (ICCs) of all six methods were generally high. The ICCs were all ≥0.77 (excellent) for the six radiographic methods in the combined group. However, a comparison of the ICCs, 95 % confidence intervals and mean absolute difference (MAD) between groups with varying degrees of ankylosis showed that the reliability of the lordosis measurements decreased in proportion to the severity of ankylosis. The Cobb L1-S1, Cobb L1-L5 and posterior tangent L1-S1 method demonstrated higher ICCs for both inter and intraobserver comparisons and the other methods showed lower ICCs in all groups. The intraobserver MAD was similar in the Cobb L1-S1 and Cobb L1-L5 (2.7°-4.3°), but the other methods showed higher intraobserver MAD. Interobserver MAD of Cobb L1-L5 only showed low in all group. These results are the first to provide a reliability analysis of different global lumbar lordosis measurement methods in AS. The findings in this study demonstrated that the Cobb L1-L5 method is reliable for measuring the global lumbar lordosis in AS.

Effect of Total Lumbar Disc Replacement on Lumbosacral Lordosis

Original article : To study effect of lumbar disc replacement on lumbosacral lordosis. There has been a growing interest in total disc replacement (TDR) for back pain with the rising concern of adjacent segment degeneration. Lumbar fusion surgery has been shown to lead to decrease in lumbar lordosis, which may account for postfusion pain resulting in less acceptable clinical outcome after successful fusion. TDR has recently emerged as an alternative treatment for back pain. There have been very few studies reporting lumbar sagittal outcome after TDR. Retrospective study of radiographic data of 17 patients who underwent TDR for single level degenerative disc disease at the author's institution was carried out. Study included measurement of preoperative and postoperative segmental and global lumbar lordosis and angle of lordosis. Patients age varied from 19 to 54 (mean, 35) years. Follow-up ranged from 12 to 24 months. TDR was performed at L4-5 level in 3 patients and L5-S1 level in 14 patients. The average values for segmental lordosis, global lordosis, and angle of lordosis at the operated level before and after surgery were 17.3, 49.7, and 8.6 degrees and 21.6, 54, and 9.5 degrees, respectively. There was a trend toward significant (P=0.02) and near significant (P=0.057) increase in segmental and global lordosis, respectively after TDR. Although prosthesis increased angle of lordosis at the level implanted in majority of the patients, the difference in preoperative and postoperative angle of lordosis was not significant (P=0.438). In addition, there was no correlation between the angle of implant of chosen and postoperative angle of lordosis at the operated level. The effect of TDR on sagittal balance appears favorable with an increase in global and segmental lumbar lordosis after single level TDR for degenerative disc disease. The degree of postoperative angle of lordosis was not affected by the angle of implant chosen at the operated level and varied independently of the implant angle.

Anterior longitudinal ligament release using the minimally invasive lateral retroperitoneal transpsoas approach: a cadaveric feasibility study and report of 4 clinical cases

Traditional procedures for correction of sagittal imbalance via shortening of the posterior column include the Smith-Petersen osteotomy, pedicle subtraction osteotomy, and vertebral column resection. These procedures require wide exposure of the spinal column posteriorly, and may be associated with significant morbidity. Anterior longitudinal ligament (ALL) release using the minimally invasive lateral retroperitoneal approach with a resultant net lengthening of the anterior column has been performed as an alternative to increase lordosis. The objective of this study was to demonstrate the feasibility and early clinical experience of ALL release through a minimally invasive lateral retroperitoneal transpsoas approach, as well as to describe its surgical anatomy in the lumbar spine. Forty-eight lumbar levels were dissected in 12 fresh-frozen cadaveric specimens to study the anatomy of the ALL as well as its surrounding structures, and to determine the feasibility of the technique. The lumbar disc spaces and ALL were accessed via the lateral transpsoas approach and confirmed with fluoroscopy in each specimen. As an adjunct, 4 clinical cases of ALL release through the minimally invasive lateral retroperitoneal transpsoas approach were reviewed. Operative technique, results, complications, and early outcomes were assessed. In the cadaveric study, sectioning of the ALL proved to be feasible from the minimally invasive lateral retroperitoneal transpsoas approach. The structures at most immediate risk during this procedure were the aorta, inferior vena cava, iliac vessels, and sympathetic plexus. The mean increase in segmental lumbar lordosis per level of ALL release was 10.2°, while global lumbar lordosis improved by 25°. Each level of ALL release took 56 minutes and produced 40 ml of blood loss on average. Visual analog scale and Oswestry Disability Index scores improved by 9 and 35 points, respectively. There were no cases of hardware failure, and as of yet no complications to report. This initial experience suggests that ALL release through the minimally invasive lateral retroperitoneal transpsoas approach may be feasible, allows for improvement of lumbar lordosis without the need of an open laparotomy/thoracotomy, and minimizes the tissue disruption and morbidity associated with posterior osteotomies.

Lordosis restoration after anterior longitudinal ligament release and placement of lateral hyperlordotic interbody cages during the minimally invasive lateral transpsoas approach: a radiographic study in cadavers

In the surgical treatment of spinal deformities, the importance of restoring lumbar lordosis is well recognized. Smith-Petersen osteotomies (SPOs) yield approximately 10° of lordosis per level, whereas pedicle subtraction osteotomies result in as much as 30° increased lumbar lordosis. Recently, selective release of the anterior longitudinal ligament (ALL) and placement of lordotic interbody grafts using the minimally invasive lateral retroperitoneal transpsoas approach (XLIF) has been performed as an attempt to increase lumbar lordosis while avoiding the morbidity of osteotomy. The objective of the present study was to measure the effect of the selective release of the ALL and varying degrees of lordotic implants placed using the XLIF approach on segmental lumbar lordosis in cadaveric specimens between L-1 and L-5. Nine adult fresh-frozen cadaveric specimens were placed in the lateral decubitus position. Lateral radiographs were obtained at baseline and after 4 interventions at each level as follows: 1) placement of a standard 10° lordotic cage, 2) ALL release and placement of a 10° lordotic cage, 3) ALL release and placement of a 20° lordotic cage, and 4) ALL release and placement of a 30° lordotic cage. All four cages were implanted sequentially at each interbody level between L-1 and L-5. Before and after each intervention, segmental lumbar lordosis was measured in all specimens at each interbody level between L-1 and L-5 using the Cobb method on lateral radiography. The mean baseline segmental lordotic angles at L1-2, L2-3, L3-4, and L4-5 were -3.8°, 3.8°, 7.8°, and 22.6°, respectively. The mean lumbar lordosis was 29.4°. Compared with baseline, the mean postimplantation increase in segmental lordosis in all levels combined was 0.9° in Intervention 1 (10° cage without ALL release); 4.1° in Intervention 2 (ALL release with 10° cage); 9.5° in Intervention 3 (ALL release with 20° cage); and 11.6° in Intervention 4 (ALL release with 30° cage). Foraminal height in the same sequence of conditions increased by 6.3%, 4.6%, 8.8% and 10.4%, respectively, while central disc height increased by 16.1%, 22.3%, 52.0% and 66.7%, respectively. Following ALL release and placement of lordotic cages at all 4 lumbar levels, the average global lumbar lordosis increase from preoperative lordosis was 3.2° using 10° cages, 12.0° using 20° cages, and 20.3° using 30° cages. Global lumbar lordosis with the cages at 4 levels exhibited a negative correlation with preoperative global lordosis (10°, R = -0.756; 20°, -0.730; and 30°, R = -0.437). Combined ALL release and placement of increasingly lordotic lateral interbody cages leads to progressive gains in segmental lordosis in the lumbar spine. Mean global lumbar lordosis similarly increased with increasingly lordotic cages, although the effect with a single cage could not be evaluated. Greater global lordosis was achieved with smaller preoperative lordosis. The mean maximum increase in segmental lordosis of 11.6° followed ALL release and placement of the 30° cage.

Long-segment posterior instrumentation and fusion with freeze-dried allograft in congenital scoliosis

The aim of this study was to evaluate the effectiveness of long-segment posterior instrumentation and allograft application in obtaining fusion in congenital scoliosis. Twenty-one patients with congenital scoliosis who were treated with long-segment posterior instrumentation (>6 levels) and freeze-dried allograft and followed up for more than 24 months were reviewed. Six patients were excluded from the study due to anterior procedures. Fifteen patients with congenital scoliosis (13 females, 2 males; mean age: 12.2 ± 3 years, range: 7-17 years) were retrospectively reviewed. Mean follow-up time was 30.9 ± 9.4 (range: 24 to 48) months. Six patients had laminectomy either due to previous posterior surgeries or to address intraspinal pathologies during the posterior fusion procedure. Preoperative, postoperative and final follow-up anteroposterior and lateral spine X-rays were reviewed. Fusion was graded according to the classification reported by Bridwell et al. Two patients were graded as 'no fusion' (pseudarthrosis), four patients as 'probably fused', and nine patients as 'definitely fused'. The major curve was corrected from an average of 68 ± 18.6 to 39.3 ± 12.2 degrees (p<0.001). Mean correction lost in the major curve was an average of 4.5 ± 5.2 degrees in the latest follow-up. There was significant correction in the compensatory curve (preoperative 37.9 ± 13.2 degrees, postoperative 20.2 ± 6.6 degrees; p=0.001). Preoperative and postoperative global thoracic kyphosis were 39.5 ± 13.3 and 32.3 ± 7.9 degrees, respectively (p=0.018). Preoperative and postoperative global lumbar lordosis was 36.3 ± 7.4 and 36.1 ± 8.9 degrees, respectively (p=0.883). Successful fusion was detected in %86.7 of patients in the final follow-up. The usage of allograft alone to achieve fusion increases the rates of pseudarthrosis while additional anterior procedure decreases the pseudarthrosis rate in patients with congenital scoliosis that require long-segment posterior instrumentation. Further studies should be performed to assess the efficacy of the usage of polysegment pedicle screw instrumentation.

Early Outcomes of Minimally Invasive Anterior Longitudinal Ligament Release for Correction of Sagittal Imbalance in Patients with Adult Spinal Deformity

The object of this study was to evaluate a novel surgical technique in the treatment of adult degenerative scoliosis and present our early experience with the minimally invasive lateral approach for anterior longitudinal ligament release to provide lumbar lordosis and examine its impact on sagittal balance. Methods. All patients with adult spinal deformity (ASD) treated with the minimally invasive lateral retroperitoneal transpsoas interbody fusion (MIS LIF) for release of the anterior longitudinal ligament were examined. Patient demographics, clinical data, spinopelvic parameters, and outcome measures were recorded. Results. Seven patients underwent release of the anterior longitudinal ligament (ALR) to improve sagittal imbalance. All cases were split into anterior and posterior stages, with mean estimated blood loss of 125 cc and 530 cc, respectively. Average hospital stay was 8.3 days, and mean follow-up time was 9.1 months. Comparing pre- and postoperative 36′′ standing X-rays, the authors discovered a mean increase in global lumbar lordosis of 24 degrees, increase in segmental lumbar lordosis of 17 degrees per level of ALL released, decrease in pelvic tilt of 7 degrees, and decrease in sagittal vertical axis of 4.9 cm. At the last followup, there was a mean improvement in VAS and ODI scores of 26.2% and 18.3%. Conclusions. In the authors' early experience, release of the anterior longitudinal ligament using the minimally invasive lateral retroperitoneal transpsoas approach may be a feasible alternative in correcting sagittal deformity.

Reliability analysis for radiographic measures of lumbar lordosis in adult scoliosis: a case–control study comparing 6 methods

Several methods are used to measure lumbar lordosis. In adult scoliosis patients, the measurement is difficult due to degenerative changes in the vertebral endplate as well as the coronal and sagittal deformity. We did the observational study with three examiners to determine the reliability of six methods for measuring the global lumbar lordosis in adult scoliosis patients. Ninety lateral lumbar radiographs were collected for the study. The radiographs were divided into normal (Cobb < 10 degrees ), low-grade (Cobb 10 degrees -19 degrees ), high-grade (Cobb >or= 20 degrees ) group to determine the reliability of Cobb L1-S1, Cobb L1-L5, centroid, posterior tangent L1-S1, posterior tangent L1-L5 and TRALL method in adult scoliosis. The 90 lateral radiographs were measured twice by each of the three examiners using the six measurement methods. The data was analyzed to determine the inter- and intra-observer reliability. In general, for the six radiographic methods, the inter- and intra-class correlation coefficients (ICCs) were all >or=0.82. A comparison of the ICCs and 95% CI for the inter- and intra-observer reliability between the groups with varying degrees of scoliosis showed that, the reliability of the lordosis measurement decreased with increasing severity of scoliosis. In Cobb L1-S1, centroid and posterior tangent L1-S1 methods, the ICCs were relatively lower in the high-grade scoliosis group (>or=0.60). And, the mean absolute difference (MAD) in these methods was high in the high-grade scoliosis group (<or=7.17 degrees ). However, in the Cobb L1-L5 and posterior tangent L1-L5 method, the ICCs were >or=0.86 in all groups. And, in the TRALL method, the ICCs were >or=0.76 in all groups. In addition, in the Cobb L1-L5 and posterior tangent L1-L5 method, the MAD was <or=3.63 degrees . And, in the TRALL method, the MAD was <or=3.84 degrees in all groups. We concluded that the Cobb L1-L5 and the posterior tangent L1-L5 methods are reliable methods for measuring the global lumbar lordosis in adult scoliosis. And the TRALL method is more reliable method than other methods which include the L5-S1 joint in lordosis measurement.

Correlation between sagittal spinopelvic balance parameters and degenerative changes of the lower lumbar spinal segments

Objective. To study correlation between spinopelvic balance parameters and degenerative changes in the low lumbar spinal segments. Material and Methods. Clinical and radiological findings in 100 patients (32 women, 68 man; mean age 38.7 ± 9.7 years) with chronic lumbodynia and lumbar ischialgia were analysed. Pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT) and global lumbar lordosis (GLL) were measured from lateral radiographs. The severity of degenerative changes in three lower lumbar segments: disk, facet, anterior and posterior supportive columns was assessed using a specially developed scale. The obtained data were statistically processed. Results. It was revealed that disk and anterior supportive column degenerations correlate negatively with parameters of PI, SS and GLL, whereas facet and posterior supportive column degenerations demonstrate positive correlation with the same parameters. Age does not effect disk and anterior supportive column degenerations, but degenerations of facet and posterior supportive column increase severely with age (r = 0.564 and r = 0.467, respectively). Conclusion. Degenerative disc changes predominate in patients with low values of PI, SS, and GLL. Degeneration of facet joints and summaraized severity of posterior supportive column degeneration predominate in patients with high values of PI, SS, and GLL.

MECHANISM OF VERTICAL POSTURE FORMATION AND PARAMETERS OF SAGITTAL SPINOPELVIC BALANCE IN PATIENTS WITH CHRONIC LOW BACK PAIN AND SCIATICA

Objective.To study parameters of sagittal spinopelvic balance in patients with chronic low back pain and sciatica, and mechanism of vertical posture formation in a sagittal plane.Material and Methods.Total of 100 patients (32 female and 68 male, mean age 38.7 years) with chronic low back pain and sciatica underwent clinical and radiological examinations. Pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), and global lumbar lordosis (GLL) were measured on lateral standing radiograms. Statistical analysis of the obtained data was performed.Results.The mean value of PI (50.7°) in patients with back pain and sciatica and in healthy volunteers was almost equal, while SS and GLL were significantly lower in patients, and PT – higher, than those in volunteers. Number of patients with PI ≤ 35 was significantly higher than that of volunteers. Pearson’s correlation coefficient between GLL and PI was 0.916, between GLL and SS – 0.902, and between GLL and PT – 0.326. Vertical posture in patients with chronic low back pain and lumbar sciatica is characterised by backward pelvic rotation relative to hip and by hypolordotic shape of the lumbar spine.Conclusion.Vertical posture in patients with low back pain and sciatica is determined by a backward rotation of the pelvis, therefore SS and GLL decrease, and PT increases. A prevalence of extremely low values of PI (≤35°) may be considered as a risk factor for lumbar spine degenerative diease. Alteration of vertical posture is a kind of protective mechanism.

Surgical results after soft system stabilization of the lumbar spine in degenerative disc disease--long-term results.

After having reported preliminary results of soft system stabilization according to Graf in a series of 27 patients with degenerative disc disease of the lumbar spine in early 1995 the authors report long term clinical and radiological results of this patient series (n = 25). At a mean period of postoperative observation of 50 months excellent, good, satisfactory, moderate and poor results were obtained in 62, 9%, 11, 1% and 11, 1%, 7, 4% and 7, 4% of the patients, respectively. The well-known phenomenon of loss of disc height at the level of posterolateral fusion and instrumentation as well as overcharge of adjacent segments were not observed after soft system stabilization. Regional as well as global lumbar lordosis were maintained and, although statistically not significant, an increase of intervertebral distance was observed in adjacent segments in flexion of the lumbar spine. These phenomena might represent pressurization of instrumented as well as adjacent discs after the insertion of ligament prostheses. It is the impression of the authors, that the Graf technique leads to good surgical results in degenerative disc disease with destabilization of lumbar motion segment(s) if the following criteria are strictly respected: 1. No or only mild arthrotic changes of the facet joints 2. Preferably minor disc degeneration/only mild loss of intervertebral distance. 3. Well trained low back muscles and 4. A clear-cut, repeatedly demonstrated pain-relief on trial anaesthesia of the corresponding articular nerves and while wearing a probatory jacket.