Lordosis In Patients Research Articles

Surgical management of cervical deformity with osteotomy

Cervical sagittal balance is as an important clinical and radiographic parameter. The normal cervical spine is lordodic, and all kyphotic deformities should be explored. In patients with suspected cervical pathology, a thorough history and physical exam is mandatory. While axial neck pain commonly exists with kyphotic deformity, radiculopathy or myelopathy often exists as well. AP and lateral radiographs detect bony abnormalities and disc space collapse. A C2–7 plumb line may be drawn to measure angulation of the cervical spine. Adjuvant CT scan, to further delineate the bony architecture, and MRI scan, to assess for neural compression, are often useful in the management of a kyphotic spine. Nonoperative management is the usual initial mode of treatment. Physical therapy, aimed at posterior cervical paraspinal muscle strengthening, may improve lordosis in patients with flexible kyphosis. Anti-inflammatory medications and injections may cause symptomatic improvement but they do not address anatomic problems. Close follow-up is needed with these patients to monitor for neurologic deterioration. Operative treatment is indicated when nonoperative management has failed or in the setting of severe or rapidly progressive neurologic symptoms. Techniques for sagittal correction exist on a spectrum. Partial facet resections or Ponte osteotomies cause relatively small segmental lordosis but result in large sagittal improvement when used in long constructs. Anterior corpectomy with adjuvant posterior soft tissue release results in more focal lordosis. Three-column osteotomies are performed at either C7 or T1 to avoid the vertebral artery. Anterior column lengthening is relatively more powerful than a pedicle subtraction osteotomy. However, anterior lengthening is associated with a higher risk of damage to the surrounding neurovascular structures and soft tissue due to traction. Lastly, a vertebral column resection results in the greatest angular correction but is rarely performed due to its high potential for complication.

Segmental and global lordosis changes with two-level axial lumbar interbody fusion and posterior instrumentation.

BackgroundLoss of lumbar lordosis has been reported after lumbar interbody fusion surgery and may portend poor clinical and radiographic outcome. The objective of this research was to measure changes in segmental and global lumbar lordosis in patients treated with presacral axial L4-S1 interbody fusion and posterior instrumentation and to determine if these changes influenced patient outcomes.MethodsWe performed a retrospective, multi-center review of prospectively collected data in 58 consecutive patients with disabling lumbar pain and radiculopathy unresponsive to nonsurgical treatment who underwent L4-S1 interbody fusion with the AxiaLIF two-level system (Baxano Surgical, Raleigh NC). Main outcomes included back pain severity, Oswestry Disability Index (ODI), Odom's outcome criteria, and fusion status using flexion and extension radiographs and computed tomography scans. Segmental (L4-S1) and global (L1-S1) lumbar lordosis measurements were made using standing lateral radiographs. All patients were followed for at least 24 months (mean: 29 months, range 24-56 months).ResultsThere was no bowel injury, vascular injury, deep infection, neurologic complication or implant failure. Mean back pain severity improved from 7.8±1.7 at baseline to 3.3±2.6 at 2 years (p < 0.001). Mean ODI scores improved from 60±15% at baseline to 34±27% at 2 years (p < 0.001). At final follow-up, 83% of patients were rated as good or excellent using Odom's criteria. Interbody fusion was observed in 111 (96%) of 116 treated interspaces. Maintenance of lordosis, defined as a change in Cobb angle ≤ 5°, was identified in 84% of patients at L4-S1 and 81% of patients at L1-S1. Patients with loss or gain in segmental or global lordosis experienced similar 2-year outcomes versus those with less than a 5° change.Conclusions/Clinical RelevanceTwo-level axial interbody fusion supplemented with posterior fixation does not alter segmental or global lordosis in most patients. Patients with postoperative change in lordosis greater than 5° have similarly favorable long-term clinical outcomes and fusion rates compared to patients with less than 5° lordosis change.

Thoracal flat back is a risk factor for lumbar disc degeneration after scoliosis surgery

Background contextLumbar segments below fused scoliotic spines are thought to be exposed to extraordinary stress. Although positive sagittal imbalance has come into focus, reports about factors influencing the outcome of these segments remain inconclusive. PurposeOur study aimed at identifying spinal risk factors for the development of lumbar degenerative disc disease (DDD) in surgically treated patients with adolescent idiopathic scoliosis (AIS). Study design/settingRetrospective comparative prognostic study (Level III) was conducted. Thirty-three patients were seen at an average follow-up of 7.5 years after either isolated selective anterior (n=18) or long combined anterior-posterior fusion (n=15) for AIS. Outcome measuresSelf-reported Scoliosis Research Society 22 questionnaire, physical examination including the detection of segmental pain and unspecific back pain, preoperative and postoperative whole-spine standing radiographs, and magnetic resonance imaging were obtained. MethodsRadiographic evaluation included the measurement of regional, coronal, and sagittal curve parameters and the assessment of spinal balance. Magnetic resonance imaging evaluation was done for preoperative and postoperative lumbar discs, according to the classification of Pfirrmann. ResultsPatients with low DDD (Pfirrmann grading <3) had a significantly higher thoracal kyphosis angle (mean 28°) than patients with advanced DDD (mean 15°). There was a trend toward a more flat-type lumbar lordosis in patients with severe DDD. Positive sagittal imbalance was associated with advanced DDD. Follow-up coronal parameters, trunk imbalance, instrumentation length, and lowest instrumented vertebra selection had no influence on DDD. Specific segmental pain could be attributed to a significantly higher coronal trunk imbalance (21 vs. 11 mm). ConclusionsThis study establishes thoracal flat back as a risk factor for lumbar DDD after spinal fusion and supports the pathogenetic role of positive sagittal imbalance in this process.

Radiographic and clinical outcome after 1- and 2-level transsacral axial interbody fusion

The paracoccygeal approach allows for instrumentation of L5/S1 and L4/5 by using a transsacral rod (AxiaLIF; TransS1, Inc.). The authors analyzed clinical and radiographic outcomes of 1- or 2-level AxiaLIF procedures with focus on durability of the construct. This was a retrospective study of 38 consecutive patients who underwent either 1-level (32 patients) or 2-level (6 patients) AxiaLIF procedures at the authors' institution. The Oswestry Disability Index (minimum clinically important difference [MCID] ≥ 12) and visual analog scale ([VAS]; MCID ≥ 3) scores were collected. Disc height and Cobb angles were measured on pre- and postoperative radiographs. Bony fusion was determined on CT scans or flexion/extension radiographs. Implantation of a transsacral rod allowed for intraoperative distraction of the L5/S1 intervertebral space and resulted in increased segmental lordosis postoperatively. At a mean follow-up time of 26.2 ± 2.4 months, however, graft subsidence (1.9 mm) abolished partial correction of segmental lordosis. Moreover, subsidence of the construct reduced L5/S1 lordosis in patients with 1-level AxiaLIF by 3.2° and L4-S1 lordosis in patients with 2-level procedures by 10.1° compared with preoperative values (p < 0.01). Loss of segmental lordosis predicted failure to improve VAS scores for back pain in the patient cohort (p < 0.05). Overall, surgical intervention led to modest symptomatic improvement; only 26.3% of patients achieved an MCID of the Oswestry Disability Index and 50% of patients an MCID of the VAS score for back pain. At last follow-up, 71.9% of L5/S1 levels demonstrated bony fusion (1-level AxiaLIF 80.8%, 2-level AxiaLIF 33.3%; p < 0.05), whereas none of the L4/5 levels in 2-level AxiaLIF fused. Five constructs developed pseudarthrosis and required surgical revision. The AxiaLIF procedure constitutes a minimally invasive technique for L5/S1 instrumentation, with low perioperative morbidity. However, the axial rod provides inadequate long-term anterior column support, which leads to subsidence and loss of segmental lordosis. Modification of the transsacral technique to allow for placement of a solid interposition graft may counteract subsidence of the construct.

Correction of Lenke 5 Adolescent Idiopathic Scoliosis Using Pedicle Screw Instrumentation

A single-center, retrospective study of 39 consecutive patients with Lenke 5 adolescent idiopathic scoliosis (AIS), all operated by a single surgeon using identical surgical technique and type of instrumentation (pedicle screws). The objective of this study is to evaluate the effect of implant density on coronal and sagittal correction in the treatment of Lenke 5 AIS. There is an increasing trend in the use of pedicle screws in spinal corrective surgery. It is reported that decreased numbers of pedicle screws (low screw density) have no effects on the clinical outcomes for patients with Lenke 1 AIS. However, no previous studies have investigated the effects of reduced density of screw implantation on coronal correction and sagittal lumbar lordosis in patients with Lenke 5 AIS. Thirty-nine consecutive patients with Lenke 5 AIS underwent single-stage posterior correction and instrumented spinal fusion with pedicle screw fixation between 2006 and 2010. The radiographs were analyzed before surgery, immediately after surgery, and at the 2-year follow-up. General information of patients was recorded. Pearson correlation analysis was used to analyze the correlation between implant density, coronal Cobb angle correction, and correction index (postoperative correction/preoperative curve flexibility). The relations between implant density and magnitude of coronal and sagittal curve correction were also investigated. The mean patient age at the time of operation was 14.5 years. The mean preoperative lumbar curve of 48.5° ± 9.2° was corrected to 13.7° ± 7.2° (72% correction) at a 2-year follow-up. There was a significant correlation between implant density and curve correction (r = 0.43, P < 0.05). No correlation was detected between implant density and correction index (r = -0.21, P = 0.20), and there was also no correlation between implant density and magnitude of sagittal curve correction (r = 0.065, P = 0.693). Without curve flexibility taken into consideration, implant density is positively correlated with thoracolumbar or lumbar coronal Cobb curve correction. No significant correlation is found between screw density and correction index, if the effect of the flexibility was eliminated. There was no association between implant density and magnitude of sagittal curve correction before and after surgery.

Protective effects of preserving the posterior complex on the development of adjacent-segment degeneration after lumbar fusion

During the past decades, lumbar fusion has increasingly become a standard treatment for degenerative spinal disorders. However, it has also been associated with an increased incidence of adjacent-segment degeneration (ASD). Previous studies have reported less ASD in anterior fusion surgeries; thus, the authors hypothesized that the integrity of the posterior complex plays an important role in ASD. This study was designed to investigate the effect of the posterior complex on adjacent instability after lumbar instrumentation and the development of ASD. To evaluate different surgical interventions, 120 patients were randomly allocated into 3 groups of 40 patients each who were statistically similar with respect to demographic and clinical data. Patients in Group A were allocated for facet joint resection and L4-5 fusion, Group B for semilaminectomy and fusion, and Group C for complete laminectomy and fusion. All of the patients were followed up for 5-7 years (mean 5.9 years). The disc height, intervertebral disc angle, dynamic intervertebral angular range of motion (ROM), L3-4 slip, and the total lordosis angle were each measured before the operation and at the final follow-up. The Japanese Orthopaedic Association (JOA) score was determined before surgery and at the final follow-up to evaluate the clinical results. Among the 3 groups, no significant differences were detected in all clinical and demographic assessments before surgery. At 3 months after surgery, the JOA score of all groups improved significantly and showed no significant differences among the groups. At the final follow-up, Group C had a significantly (p < 0.05) lower JOA score than the other 2 groups. Moreover, the disc height and total lumbar lordosis in patients of Group C were significantly decreased compared with disc height and total lumbar lordosis in the other 2 groups. In contrast, disc angle, dynamic angular ROM, and listhesis were significantly higher in Group C than in the other 2 groups. Twenty-four patients showed signs of ASD after the operation (3 patients in Group A, 4 in B, and 17 in C). The number of patients in Group C showing ASD was significantly different from that in Groups A and B. During follow-up for 6 years, a significantly higher number of patients with ASD were noted in the complete-laminectomy group. The number of reoperations for treating ASD was much higher in this patient group than in the patients undergoing facet joint resection and L4-5 fusion or semilaminectomy and fusion. Therefore, preserving the posterior complex as much as possible during surgery plays an important role in preventing ASD and in reducing the reoperation rate.

Analysis of risk factors for loss of lumbar lordosis in patients who had surgical treatment with segmental instrumentation for adolescent idiopathic scoliosis

Iatrogenic flattening of lumbar lordosis in patients with adolescent idiopathic scoliosis (AIS) was a major downside of first generation instrumentation. Current instrumentation systems allow a three-dimensional scoliosis correction, but flattening of lumbar lordosis remains a significant problem which is associated with decreased health-related quality of life. This study sought to identify risk factors for loss of lumbar lordosis in patients who had surgical correction of AIS with the use of segmental instrumentation. Patients were included if they had surgical correction for AIS with segmental pedicle screw instrumentation Lenke type 1 or 2 and if they had a minimum follow-up of 24 months. Two groups were created, based on the average loss of lumbar lordosis. The two groups were then compared and multivariate analysis was performed to identify parameters that correlated to loss of lumbar lordosis. Four hundred and seventeen patients were analyzed for this study. The average loss of lumbar lordosis at 24 months follow-up was an increase of 10° lordosis for group 1 and a decrease of 15° for group 2. Risk factors for loss of lumbar lordosis included a high preoperative lumbar lordosis, surgical decrease of thoracic kyphosis, and the particular operating surgeon. The lowest instrumented vertebra or spinopelvic parameters were two of many parameters that did not seem to influence loss of lumbar lordosis. This study identified important risk factors for decrease of lumbar lordosis in patients who had surgical treatment for AIS with segmental pedicle screw instrumentation, including a high preoperative lumbar lordosis, surgical decrease of thoracic kyphosis, and factors attributable to a particular operating surgeon that were not quantified in this study.

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.

Sagittal alignment of the cervical spine after neck injury

The normal sagittal alignment of the cervical spine is lordotic and is affected by the posture of the head and neck. The question of whether loss of cervical lordosis is the result of muscle spasm after injury or a normal variation, and the clinical significance of such changes in sagittal profile of the cervical spine has been an issue of several studies. The purpose of this paper is to study the incidence of normal cervical lordosis and its changes after neck injury compared to the healthy population. We studied the lateral radiographs of the cervical spine of 60 patients with neck injury compared to 100 patients without a neck injury. Lateral radiographs were obtained in the standing or sitting position, and the curvature of the cervical spine was measured using the angle formed between the inferior end plates of the C2 and C7 vertebrae. In the patients without neck injury, lordotic and straight cervical spine sagittal alignment was observed in 36.5% each, double curvature in 17%, and kyphotic in 10%. In the patients with neck injury, lordotic sagittal alignment was observed in 36%, straight in 34%, double curvature in 26% and kyphotic in 4%. No significant difference between the two groups regarding all types of sagittal alignment of the cervical spine was found (p > 0.100). The alterations in normal cervical lordosis in patients with neck injury must be considered coincidental. These alterations should not be associated with muscle spasm caused by neck pain.

Restoration and Preservation of Disc Height and Segmental Lordosis With Circumferential Lumbar Fusion

Retrospective radiographic analysis. To determine whether restoration and preservation of (a) disc height and (b) segmental lordosis differ between patients treated with circumferential lumbar fusion using a bone graft or a cage for anterior support. Restoration of disc height and lordosis is considered to be of crucial importance in circumferential fusion (CF). To determine whether restoration and preservation of disc height and segmental lordosis are dependent on the type of anterior support used, we compared the use of a cage with that of a bone graft in CF. We retrospectively analyzed disc height and segmental lordosis in patients treated with primary lumbar monosegmental CF. The minimum period of follow-up was 9 months. A cage was used for anterior support in 23 patients and a bone graft in a further 23 patients. Disc height was determined on radiographs using an earlier introduced and validated distortion-compensated roentgen analysis, which was developed to compensate for distortion in central projection, off-center position, variation of stature, axial rotation, and lateral tilt of the spine. Disc height was restored in both groups but differences between preoperative and postoperative disc heights were significantly greater in the cage group (P=0.006). The cage also proved to be superior with regard to disc height preservation after follow-up (P=0.001). In addition, there was significantly less postoperative loss of segmental lordosis in the cage group (P=0.026). The cage proved superior to the bone graft as anterior support in CF with respect to restoration/preservation of lordosis and disc height. However, no conclusions concerning clinical outcome or cost effectiveness can be drawn on the basis of this study.

The effect of body mass index on lumbar lordosis on the Mizuho OSI Jackson spinal table

Study design: Prospective cohort study.Clinical question: Does the patients' body mass index (BMI) influence the degree of intraoperative lumbar lordosis in patients undergoing operative treatment on the Mizuho Orthopedic Systems Incorporated (OSI) Jackson spinal table?Methods: Twenty-four consecutive patients undergoing posterior spinal instrumentation and fusion on the Jackson table, excluding those with sagittal malalignment, underwent standing preoperative and prone intraoperative lateral x-rays. Intervertebral body angle measurements were obtained from L1–S1 using the modified method of Cobb. Changes in angle measurements were compared to BMI using linear regression and ANOVA.Results: We found a mean lordosis of 52.6° in standing preoperative x-rays compared to a prone position mean lordosis of 61.5° on the Jackson table. The mean change was 8.88° with a range of 0°–18°. A linear association between lordosis and BMI was demonstrated (P < .0022). As BMI increased, so did lordosis (correlation coefficient, 0.59).Conclusions: The current study is the first in which a correlation of patient body mass and use of the Jackson table has been evaluated. These data suggest that BMI influences lumbar lordosis on the Jackson table and that care must be used when dealing with a population with large BMI on the Jackson table.Methods evaluation and class of evidence (CoE)Methodological principle:Study design: Prospective cohort• Retrospective cohort Case control Case seriesMethods Patients at similar point in course of treatment• Follow-up ≥85%• Similarity of treatment protocols for patient groups• Patients followed for long enough for outcomes to occur• Control for extraneous risk factorsEvidence class:II*Authors must provide a description of robust baseline characteristics, and control for those that are potential prognostic factors.The definiton of the different classes of evidence is available on page 83.

Pedicle subtraction osteotomies for the correction of post-traumatic thoracolumbar kyphosis

Traumatic compression fractures are usually treated non-surgically. In most patients without osteoporosis, such fractures heal without any sequelae. However, some patients develop a post-traumatic kyphosis that can lead to severe pain and disability, refractory to non-surgical management. In such patients, correction of the kyphosis ultimately may be the only definitive treatment. Pedicle subtraction osteotomies have been used in non-traumatic settings to correct kyphotic deformities or restore lordosis in patients in symptomatic positive sagittal balance. We apply this technique in the setting of post-traumatic kyphosis, and we performed the osteotomies at the level of the compression fracture.

Changes in sagittal alignment after restoration of lower lumbar lordosis in patients with degenerative flat back syndrome

Object The authors investigate the correlation between thoracic and lumbar curves in patients with degenerative flat back syndrome, and demonstrate the predictability of spontaneous correction of the thoracic curve and sacral angle after surgical restoration of lower lumbar lordosis. Methods The cases of 28 patients treated with combined anterior and posterior spinal arthrodesis were retrospectively reviewed. Inclusion criteria included loss of lower lumbar lordosis resulting in sagittal imbalance. Total lumbar lordosis, thoracic kyphosis, sacral slope, and C-7 plumb line length were measured on pre- and postoperative lateral views of the whole spine. Postoperative changes in thoracic kyphosis, sacral slope, and length of the C-7 plumb line were measured and evaluated according to extent of lumbar lordosis restoration. Results The mean (± standard deviation) preoperative sagittal imbalance was 64.6 ± 63.2 mm, which improved to 15.8 ± 20.7 mm after surgery (p < 0.0001). The preoperative mean lumbar lordosis was 15.6 ± 14.1°, which increased to 40.3 ± 14.5° at follow-up (p < 0.0001). The preoperative mean thoracic kyphosis was 1.6 ± 10.5° and increased to 17.2 ± 12.5° at follow-up (p < 0.0001). Significant preoperative correlations existed between kyphosis and lordosis (r = 0.628, p = 0.0003), and between lordosis and sacral slope (r = 0.647, p = 0.0002). Postoperative correlations also existed between kyphosis and lordosis (r = 0.718, p < 0.0001 and r = 0.690, p < 0.0001, respectively). Conclusions Lower lumbar lordosis plays an important role in sagittal alignment and balance. Surgical restoration of lumbar lordosis results in predictable spontaneous correction of the thoracic curve and sacral slope in patients with degenerative flat back syndrome.

Changes in sagittal alignment after restoration of lower lumbar lordosis in patients with degenerative flat back syndrome

The authors investigate the correlation between thoracic and lumbar curves in patients with degenerative flat back syndrome, and demonstrate the predictability of spontaneous correction of the thoracic curve and sacral angle after surgical restoration of lower lumbar lordosis. The cases of 28 patients treated with combined anterior and posterior spinal arthrodesis were retrospectively reviewed. Inclusion criteria included loss of lower lumbar lordosis resulting in sagittal imbalance. Total lumbar lordosis, thoracic kyphosis, sacral slope, and C-7 plumb line length were measured on pre- and postoperative lateral views of the whole spine. Postoperative changes in thoracic kyphosis, sacral slope, and length of the C-7 plumb line were measured and evaluated according to extent of lumbar lordosis restoration. The mean (+/- standard deviation) preoperative sagittal imbalance was 64.6 +/- 63.2 mm, which improved to 15.8 +/- 20.7 mm after surgery (p < 0.0001). The preoperative mean lumbar lordosis was 15.6 +/- 14.1 degrees, which increased to 40.3 +/- 14.5 degrees at follow-up (p < 0.0001). The preoperative mean thoracic kyphosis was 1.6 +/- 10.5 degrees and increased to 17.2 +/- 12.5 degrees at follow-up (p < 0.0001). Significant preoperative correlations existed between kyphosis and lordosis (r = 0.628, p = 0.0003), and between lordosis and sacral slope (r = 0.647, p = 0.0002). Postoperative correlations also existed between kyphosis and lordosis (r = 0.718, p < 0.0001 and r = 0.690, p < 0.0001, respectively). Lower lumbar lordosis plays an important role in sagittal alignment and balance. Surgical restoration of lumbar lordosis results in predictable spontaneous correction of the thoracic curve and sacral slope in patients with degenerative flat back syndrome.

Cervical Lordosis in Patients Who Underwent Anterior Cruciate Ligament Injury: A Cross-Sectional Study

It has been proposed that intraoral devices can influence cervical posture. Cervical posture might also be influenced by stimuli from the lower limbs, such as injury of the knee. The hypothesis to be tested is that intraoral devices are useful during the rehabilitation of orthopedic patients to accelerate the restoration of postural control. This study evaluates cervical posture on lateral skull radiographs in subjects who suffered anterior cruciate ligament (ACL) injury of the left knee. Twenty adult Caucasian males (mean age 30.6±9.2 yrs.) with ACL injury of the left knee were compared with 40 control subjects (mean age 27.9±7.2) who did not show any ACL injury. Lateral skull radiographs, made in natural head position (mirror position), were obtained for all subiects. Various postural and morphological variables were individualized on each radiograph. To assess errors due to landmark identification, duplicate measurements were made of 15 radiographs and compared using the Dahlberg formula. The method error from both sources was less than 0.5° for all angular measurements and less than 0.5 mm for all linear measurements. No difference was observed between the two groups in any of the morphological variables of face or in the cervical lordosis angle (CVT/EVT). However, subjects in the study group showed significantly higher craniocervical angulations (SN/OPT, SN/CVT, SN/EVT, pns-ans/OPT, pns-ans/CVT, pnsans/EVT, GoGn/OPT, GoGn/CVT, GoGn/EVT) compared with the control subjects (p<0.001). The subjects with ACL injury had significant head extension compared with the control subjects.

The effect of intraoperative hip position on maintenance of lumbar lordosis: a radiographic study of anesthetized patients and unanesthetized volunteers on the Wilson frame.

The effect of intraoperative hip position on maintenance of lumbar lordosis was evaluated radiographically in 13 anesthetized patients and 14 unanesthetized volunteers positioned on a Wilson frame (MDT Corp., Torrance, CA). To evaluate the effect of hip position on total and segmental lumbar lordosis in patients and volunteers in standardized positions: standing and with hips extended and flexed on a Wilson frame. Preservation of lordosis during instrumented lumbar fusion is critical for maintenance of normal sagittal alignment. It is customary to extend the hips on certain positioning devices to maximize lordosis maintenance. However, little information exists concerning the degree to which this actually affects lumbar lordosis. Further, the question of how individuals are specifically affected intraoperatively by differences of position on the same device remains unanswered. Preoperative standing and intraoperative lateral lumbar spine radiographs with patients' hips in standardized flexed and extended positions were obtained (n = 13). Similar radiographs were obtained of asymptomatic volunteers (n = 14). Lumbar lordosis (L1-S1) and intervertebral body angles at each level were measured. Data were analyzed for changes in total and segmental lordosis between standing and intraoperative positions for all subjects. In the patient group, 95% of preoperative standing lordosis was maintained with the patients' hips extended. With hips flexed from 19 degrees to 48 degrees (mean, 33 degrees), 74% of lordosis was maintained. In the volunteer group, 98% of standing lordosis was maintained with volunteers' hips extended; with their hips flexed 20 degrees to 36 degrees (mean, 28 degrees), 86% of lordosis was maintained. Hip flexion was associated with a significant decrease in lordosis in patients and volunteers. Positioning in maximal hip extension optimizes lordosis preservation. While other devices have been shown to have specific effects on lordosis, the Wilson frame can permit easy adjustment of the lumbar sagittal contour to facilitate either preservation or reduction in lordosis.

Change in Spinal Curvature following Release of Tethered Spinal Cord Associated with Spina bif ida

Changes in spinal curvature, scoliosis, kyphosis and lordosis are associated with the growth of patients with myelomeningocele. Previous investigators have stated that progressive developmental scoliosis is related to tethered spinal cord. In order to investigate the relationship of tethered spinal cord release to progression of spinal curvature, we surveyed the medical records of 262 patients with a history of one or more tethered spinal cord release. For 216 of these patients, a total of 2,369 serial spine x-rays, obtained over a 20-year period, were reviewed by the standard Cobb method for progression of scoliosis, thoracic kyphosis and lordosis. In addition, the serial spine x-rays of 74 patients without clinical findings of tethered spinal cord were collected and reviewed for comparison of progressive scoliosis and kyphosis. One hundred and sixty normal lumbar x-rays were evaluated to compare the progression of the lordotic curve in patients with tethered cord release with a normal population. Progression of scoliosis plateaued or declined following release of tethered cord in patients with lumbar and sacral level lesions, however, tether release did not halt the progression of scoliosis in the thoracic level group. Tethered cord release altered the course of lordosis in L1 through L3 level lesions, but had little affect on the normal progression of lordosis in patients with L4, L5 or sacral level lesions. Finally, tethered spinal cord release appears to be associated with a decrease in the incidence and magnitude of kyphosis.