Arthrodesis to L5 versus S1 in long instrumentation and fusion for degenerative lumbar scoliosis

There is a debate regarding the distal fusion level for degenerative lumbar scoliosis. Whether a healthy L5-S1 motion segment should be included or not in the fusion remains controversial. The purpose of this study was to determine the optimal indication for the fusion to the sacrum, and to compare the results of distal fusion to L5 versus the sacrum in the long instrumented fusion for degenerative lumbar scoliosis. A total of 45 patients who had undergone long instrumentation and fusion for degenerative lumbar scoliosis were evaluated with a minimum 2 year follow-up. Twenty-four patients (mean age 63.6) underwent fusion to L5 and 21 patients (mean age 65.6) underwent fusion to the sacrum. Supplemental interbody fusion was performed in 12 patients in the L5 group and eleven patients in the sacrum group. The number of levels fused was 6.08 segments (range 4–8) in the L5 group and 6.09 (range 4–9) in the sacrum group. Intraoperative blood loss (2,754 ml versus 2,938 ml) and operative time (220 min versus 229 min) were similar in both groups. The Cobb angle changed from 24.7° before surgery to 6.8° after surgery in the L5 group, and from 22.8° to 7.7° in the sacrum group without statistical difference. Correction of lumbar lordosis was statistically better in the sacrum group (P = 0.03). Less correction of lumbar lordosis in the L5 group seemed to be associated with subsequent advanced L5-S1 disc degeneration. The change of coronal and sagittal imbalance was not different in both groups. Subsequent advanced L5-S1 disc degeneration occurred in 58% of the patients in the L5 group. Symptomatic adjacent segment disease at L5-S1 developed in five patients. Interestingly, the development of adjacent segment disease was not related to the preoperative grade of disc degeneration, which proved minimal degeneration in the five patients. In the L5 group, there were nine patients of complications at L5-S1 segment, including adjacent segment disease at L5-S1 and loosening of L5 screws. Seven of the nine patients showed preoperative sagittal imbalance and/or lumbar hypolordosis, which might be risk factors of complications at L5-S1. For the patients with sagittal imbalance and lumbar hypolordosis, L5-S1 should be included in the fusion even if L5-S1 disc was minimal degeneration.     

Bedeutung des sagittalen Profils bei Revisionseingriffen an der Wirbels?ule

Ignoring the sagittal profile in primary spinal fusion surgery is a common reason for revision surgery. Therefore, it is important that in cases of spinal revision surgery the sagittal alignment is realized. The physiological alignment of the instrumented spine should also indirectly influence the profile of the non-stabilized spine cranial and caudal to the fusion. Patients with normal C7 plumb-line and a physiological sacral inclination have a lower incidence of adjacent segment degeneration. Sagittal imbalance after revision surgery is a risk factor for recurrent pseudarthrosis. In cases of pseudarthrosis a combined approach may be more effective in realizing sagittal balance und enhancing rates of fusion.     

Dynamische Versorgung der Lendenwirbels?ule

Total disc replacement and posterior dynamic stabilization represent alternatives to lumbar spinal fusion which should reduce the risk of adjacent segment degeneration. Disc replacement is indicated for pure discopathy without facet joint degeneration. Spinopelvic balance influences the implant's biomechanics. Therefore pelvic incidence, sacral slope, segmental lordosis and the mean axis of rotation need to be considered. Dynamic stabilization is indicated in moderate discopathy and facet joint degeneration, in degenerative spondylolisthesis grade I with a hypermobile segment and in dynamic lumbar stenosis. The combination of caudal fusion and cranial dynamic stabilization allows a better maintenance of lordosis with multiple level instrumentation and prevents adjacent segment degeneration. If pelvic incidence and sacral slope are high, L5-S1 should be fused because of elevated shear forces.     

Higher risk of adjacent segment degeneration after floating fusions: long-term outcome after low lumbar spine fusions

STUDY DESIGN: We report the long-term outcome after mono-segmental and bisegmental fusions at the lumbar L4-S1 region of the spine. OBJECTIVE: Long-term clinical and radiologic outcome measures were used to determine a lumbar fusion's contribution to degenerative changes in adjacent motion segments (ASD). SUMMARY OF BACKGROUND DATA: The role of low lumbar spinal fusions and their long-term contribution to accelerated degenerative changes in the adjacent motion segments continues to be a subject of controversy. PATIENTS AND METHODS: We followed-up 102 patients with an average age of 54 (22 to 78) years and a follow-up time of 14 (3 to 22) years. RESULTS: Overall results in patients were good, the Oswestry-Disability Index (ODI) showed an average of 26% (0% to 70%) at follow-up, the Visual Analog Scale rose from 2.7 (postoperative) and 2.9 (12 wk follow-up) to 3.6 (latest follow-up) points, respectively. Patient satisfaction with their health-related situation at follow-up was 69% (15% to 100%). Patients who underwent fusions of the segment L5/S1 showed a significant (P<0.05) lower risk for ASD than patients with fusions L4/5 (20% vs. 46%). Compared with L4/5 fusions, bisegmental L4-S1 fusions showed a similar trend (P=0.06) with a lower risk for ASD (24%). Objective and subjective clinical results showed no differences between these groups. Patients suffering from ASD showed significant (P<0.05) reduced sacral inclination and lumbar lordosis angles and also significant (P<0.05) higher ODI values compared with non-ASD patients. CONCLUSIONS: We conclude that floating fusions of single low lumbar segments are more likely to result in ASD and are negatively influenced by sagittal plane abnormalities.     

Lumbar motion-sparing surgery

Surgical treatment of the painful lumbar spine segment is a challenging endeavor. The ideal surgical intervention has a predictably good clinical effect, a low incidence of complications, and long-term durability. The gold standard for surgical intervention is a lumbar spine fusion, but the long-term durability of lumbar fusions is compromised with the development of adjacent level degeneration. Due to these concerns, motion-sparing surgical implants, including artificial discs, dynamic stabilization techniques, and nucleus pulposus replacements, have been developed to simultaneously treat the painful motion segment while at the same time preserving sufficient motion to decrease the chances of adjacent level degeneration.     

Anschlusssegmentbeweglichkeit nach monosegmentaler Bandscheibenprothesenimplantation und monosegmentaler Fusion Segment L4/5

Background

Preservation of movement at the treated segment and possible reduction of adjacent segment effects is assumed to be an advantage of non-fusion technologies over fusion. The aim of this study was to compare the segmental range of motion (ROM) at the operative level, the cranial and caudal adjacent levels and the global lumbar spine ROM (L2-S1) after monosegmental fusion and total disc replacement (TDR).

Patients and methods

Radiographic data was collected from 27 patients with level 1 degenerative disc disease operated at level L4/5. The ROM was assessed at the index level (L4/5), the cranial and caudal adjacent level and for the lumbar spine (L2-S1).

Results

In the TDR group no significant changes of lumbar spine ROM (L2–S1) and segmental ROM (index level, cranial and caudal adjacent level) were noticed. In the fusion group there was a significant reduction of lumbar ROM (L2-S1) and index level ROM. Additionally the relative ROM in the adjacent caudal segment significantly increased while no changes were seen in the cranial segment.

Conclusion

The relative ROM was significantly increased in monosegmental fusion at level L4/5 compared to TDR. To what extent this fact may result in early adjacent segment degeneration in cases of fusion compared to TDR is still unknown.     

Long-term follow-up of functional outcomes and radiographic changes at adjacent levels following lumbar spine fusion for degenerative disc disease

There are very few studies with more than 20 years' follow-up of lumbar spine fusions for disc degeneration. Currently, there is a lot of interest in the subject of degenerative changes above the level of fusion; this study is concerned with such changes in the very long term (30 years). Twenty-eight patients showing sound fusion on radiographs following posterior midline spinal fusion performed by a single surgeon between 1968 and 1970 were compared with an age- and gender-matched group of 28 patients who had undergone surgery for degenerative disc disease without fusion during the same period, by the same surgeon and using similar criteria for evaluation (Short Form 36 and Oswestry Disability Index; functional testing using self-paced walk and timed up-and-go; flexion and extension lateral radiographs of the lumbar spine). In this study, the incidence of radiographic changes at levels above the level of previous involvement was twice as high in the fusion group as in the non-fusion group. However, there was no statistically significant difference between the two groups in the outcomes measured using validated scales and functional testing. The study emphasises the importance of complete evaluation of these patients using validated outcome measurement instruments against the background of radiographic changes and subjective assessment of back pain. It also shows that radiographic changes do not necessarily mean functional impairment in all patients following lumbar spine fusion for degenerative disc disease.     

Risk factors for adjacent segment disease after lumbar fusion

The incidence of adjacent segment problems after lumbar fusion has been found to vary, and risk factors for these problems have not been precisely verified, especially based on structural changes determined by magnetic resonance imaging. The purpose of this retrospective clinical study was to describe the incidence and clinical features of adjacent segment disease (ASD) after lumbar fusion and to determine its risk factors. We assessed the incidence of ASD in patients who underwent lumbar or lumbosacral fusions for degenerative conditions between August 1995 and March 2006 with at least a 1-year follow-up. Patients less than 35 years of age at the index spinal fusion, patients with uninstrumented fusion, and patients who had not achieved successful union were excluded. Of the 1069 patients who underwent fusions, 28 (2.62%) needed secondary operations because of ASD and were included in this study. In order to identify the risk factors, we matched a disease group and a control group. The disease group consisted of 26 of the 28 patients with ASD, excluding the 2 patients for whom we did not have initial MRI data. Each patient in the disease group was matched by age, sex, fusion level and follow-up period with a control patient. The assumed risk factors included disc and facet degeneration, instability, listhesis, rotational deformity, and disc wedging. The mean age of the 28 patients with ASD requiring surgical treatment was 58.4 years, which did not differ significantly from that of the population in which ASD did not develop (58.2 years, p = 0.894). Of the 21 patients who underwent floating fusion, only 1 developed distal ASD. Facet degeneration was a significant risk factor (p < 0.01) on logistic regression analysis. The incidence of distal ASD was much lower than that of proximal ASD. Pre-existing facet degeneration may be associated with a high risk of adjacent segment problems following lumbar fusion procedures.     

Loading of the lumbar spine during transition from standing to sitting: effect of fusion versus motion preservation at L4–L5 and L5–S1

BACKGROUND CONTEXTTransition from standing to sitting significantly decreases lumbar lordosis with the greatest lordosis-loss occurring at L4–S1. Fusing L4–S1 eliminates motion and thus the proximal mobile segments maybe recruited during transition from standing to sitting to compensate for the loss of L4–S1 mobility. This may subject proximal segments to supra-physiologic flexion loading.PURPOSEAssess effects of instrumented fusion versus motion preservation at L4–L5 and L5–S1 on lumbar spine loads and proximal segment motions during transition from standing to sitting.STUDY DESIGNBiomechanical study using human thoracolumbar spine specimens.METHODSA novel laboratory model was used to simulate lumbosacral alignment changes caused by a person's transition from standing to sitting in eight T10-sacrum spine specimens. The sacrum was tilted in the sagittal plane while constraining anterior-posterior translation of T10. Continuous loading-data and segmental motion-data were collected over a range of sacral slope values, which represented transition from standing to different sitting postures. We compared different constructs involving fusions and motion preserving prostheses across L4–S1.RESULTSAfter L4–S1 fusion, the sacrum could not be tilted as far posteriorly compared to the intact spine for the same applied moment (p<.001). For the same reduction in sacral slope, L4–S1 fusion induced 2.9 times the flexion moment in the lumbar spine and required 2.4 times the flexion motion of the proximal segments as the intact condition (p<.001). Conversely, motion preservation at L4–S1 restored lumbar spine loads and proximal segment motions to intact specimen levels during transition from standing to sitting.CONCLUSIONSIn general, sitting requires lower lumbar segments to undergo flexion, thereby increasing load on the lumbar disks. L4–S1 fusion induced greater moments and increased flexion of proximal segments to attain a comparable seated posture. Motion preservation using a total joint replacement prosthesis at L4–S1 restored the lumbar spine loads and proximal segment motion to intact specimen levels during transition from standing to sitting.CLINICAL SIGNIFICANCEAfter L4–S1 fusion, increased proximal segment loading during sitting may cause discomfort in some patients and may lead to junctional breakdown over time. Preserving motion at L4–S1 may improve patient comfort and function during activities of daily living, and potentially decrease the need for adjacent level surgery.     

腰椎融合辅以邻近节段动态固定治疗腰椎退行性疾病的早期临床疗效观察

目的 评价腰椎融合辅以邻近节段K-Rod动态固定治疗腰椎退行性疾病的临床疗效及对腰椎运动功能的影响,探讨K-Rod动态固定对邻近节段保护的优劣.方法 回顾性分析2010年4月~2011年9月采用椎间融合辅以邻近节段K-Rod 动态固定及单节段椎间植骨融合内固定术的51例患者.A组（K-Rod组）24例患者术前邻近节段存在退变,行单节段融合辅以邻近节段K-Rod动态固定;B组（单节段融合组）27例患者术前邻近节段无不稳或退变,行单节段椎间植骨融合内固定术.对比评价2组腰腿痛视觉模拟量表（visual analogue scale,VAS）评分、Oswestry 功能障碍指数（ Oswestry disability Index,ODI） 、椎间隙高度、腰椎总活动度（range of motion,ROM）及头侧邻近第一节段活动度（ROM1）、头侧邻近第二节段或尾侧第一邻近节段活动度（ROM2）、保护节段及邻近节段退变（adjacent segment degeneration,ASD）发生率.结果随访 24~37个月.2组患者术后VAS评分及ODI均显著改善,且2组间差异无统计学意义.2组间腰椎总ROM术前及末次随访之间均无差异.A组保护节段末次随访时椎间隙高度与术前无差异.2组ROM1及ROM2术前术后相比差异均有显著统计学意义,2组间相比差异无统计学意义.A组末次随访时8例患者出现11（11/138,8%）枚螺钉松动;B组无螺钉松动.结论 腰椎融合辅以邻近节段动态固定具有较好的临床疗效,增加的动态固定保护了术前已存在退变的节段,避免了多节段融合,降低了单节段融合邻椎病的风险,因此适应证选择合适,具有较好的临床应用价值.     

腰椎单节段固定融合术后上位相邻节段退变及其与临床疗效的关系

目的:探讨腰椎单节段固定融合术后上位相邻节段退变及其与临床效果的关系,分析退变的相关因素。方法:回顾性分析2004年10月～2009年5月采用后路单节段椎弓根螺钉固定并椎体间cage植骨融合术治疗的49例L4/5退变性失稳患者,男22例,女27例,年龄28～72岁(平均53.4岁)。所有患者术前均行骨密度检测。在X线片上测量固定节段及其上位相邻节段椎间盘高度、椎间隙动态角度变化、椎体滑移距离以及固定节段和腰椎前凸角、腰骶关节角,并通过JOA评分及腰功能障碍指数(ODI)评价临床效果。根据末次随访时上位相邻节段有无影像学退变,分为退变组与非退变组,比较两组间临床效果及影像学测量结果。结果:随访时间为13～52个月,平均为29.3个月,所有患者术后均无神经损害加重症状。末次随访时11例患者(22%)出现上位相邻节段影像学退变。两组患者手术时的平均年龄有显著性差异(P<0.05);术前骨密度、腰椎前凸角、腰骶关节角、L4/5前凸角和椎体间滑移距离均无显著性差异(P>0.05);末次随访时L3/4椎体间滑移距离、L3/4椎间盘高度以及椎间隙动态成角变化值均存在显著性差异(P<0.05),ODI和JOA评分改善率无显著性差异(P>0.05)。患者年龄与末次随访时固定上位相邻节段椎间盘高度、椎间隙动态成角、椎体间滑移距离变化值存在正相关性,相关系数分别为0.353、0.521、0.472,余测量指标与固定上位相邻节段影像学指标变化均无显著相关性。结论:单节段腰椎固定融合术后上位相邻节段影像学退变与临床效果之间无显著相关性。此退变与患者年龄相关,而与骨密度和术前腰椎影像学测量指标无显著相关性。     

Kinematic evaluation of the adjacent segments after lumbar instrumented surgery: a comparison between rigid fusion and dynamic non-fusion stabilization

The aim of the current study was to evaluate changes in lumbar kinematics after lumbar monosegmental instrumented surgery with rigid fusion and dynamic non-fusion stabilization. A total of 77 lumbar spinal stenosis patients with L4 degenerative spondylolisthesis underwent L4–5 monosegmental posterior instrumented surgery. Of these, 36 patients were treated with rigid fusion (transforaminal lumbar interbody fusion) and 41 with dynamic stabilization [segmental spinal correction system (SSCS)]. Lumbar kinematics was evaluated with functional radiographs preoperatively and at final follow-up postoperatively. We defined the contribution of each segmental mobility to the total lumbar mobility as the percent segmental mobility [(sagittal angular motion of each segment in degrees)/(total sagittal angular motion in degrees) × 100]. Magnetic resonance imaging was performed on all patients preoperatively and at final follow-up postoperatively. The discs were classified into five grades based on the previously reported system. We defined the progress of disc degeneration as (grade at final follow-up) − (grade at preoperatively). No significant kinematical differences were shown at any of the lumbar segments preoperatively; however, significant differences were observed at the L2–3, L4–5, and L5–S1 segments postoperatively between the groups. At final follow-up, all of the lumbar segments with rigid fusion demonstrated significantly greater disc degeneration than those with dynamic stabilization. Our results suggest that the SSCS preserved 14% of the kinematical operations at the instrumented segment. The SSCS may prevent excessive effects on adjacent segmental kinematics and may prevent the incidence of adjacent segment disorder.     

The relationship between disc degeneration, facet joint osteoarthritis, and stability of the degenerative lumbar spine

Degenerative processes in the disc and facet joints affect the stability of the motion segment. The exact relations among disc degeneration, facet joint osteoarthritis, and the kinematics of the motion segment are not well defined in the literature. Magnetic resonance imaging and functional radiography of the lumbar spine were analyzed to examine the relations among segmental instability, facet joint osteoarthritis, and disc degeneration in patients with degenerative disorders of the lumbar spine. Seventy consecutive patients (mean age, 46 years) had both magnetic resonance imaging and flexion and extension radiographs of the lumbar spine. The lumbar instability was classified into abnormal tilting on flexion, rotatory instability in the sagittal plane, and translatory instability. Translatory instability was subdivided into anterior, posterior, and anteroposterior translatory instability. Disc degeneration as seen on T2-weighted sagittal images was classified into five grades. Facet joint osteoarthritis as seen on axial T1-weighted images was divided into four grades. This study revealed that the kinematics of the lumbar motion segment are affected by disc degeneration and facet joint osteoarthritis. Abnormal tilting movement on flexion and anteroposterior translatory instability both had negative associations with facet joint osteoarthritis. However, anterior translatory instability was positively associated with disc degeneration and facet joint osteoarthritis. Rotatory instability in the sagittal plane and posterior translatory instability were not associated with disc degeneration and facet joint osteoarthritis.     

单节段后路椎间融合内固定术对腰椎前凸角度变化的影响

目的探讨L4/L5单节段后路椎间融合器置入椎弓根内固定术对患者腰椎前凸角度变化的影响。方法回顾性随访分析43例L4/L5单节段后路椎间融合器置入配合使用椎弓根内固定术的患者,对患者术前、术后总腰椎前凸角度、L4/L5节段前凸角、骶骨倾斜角进行比较。结果 L4/L5单节段后路椎间融合术后患者总腰椎前凸角度与术前对比平均增加8.4°（P〈0.01）;L4/L5节段前凸角与术前对比平均增加3.5°（P〈0.05）;骶骨倾斜角与术前对比平均增加4.2°（P〈0.05）。结论 L4/L5单节段后路椎间融合器置入椎弓根内固定术可以明显改善患者腰椎前凸角度,对于改善腰椎序列和缓解患者术后腰痛症状以及延缓邻近节段退变均有积极意义。     

后路腰椎椎间融合术对邻近节段退变的影响

目的 腰椎融合术改变了腰椎的生物力学环境,使邻近节段应力集中,本研究就后路腰椎椎间融合术(posterior lumbar interbody fusion,PLIF)对邻近节段退变(adjacent segment degeneration,ASD)的影响进行探讨.方法 2002～2006年,采用PLIF治疗腰椎退...     

Early sacral stress fracture after reduction of spondylolisthesis and lumbosacral fixation: case report

OBJECTIVE AND IMPORTANCE: Early sacral fracture is an extremely rare complication of instrumented lumbosacral fusion seen in older, osteopenic women. Previous reports have attributed the problem to the use of multisegmental (three or more levels) fixation, with the transfer of stress forces from rigid spinal implants to the sacrum. We report the only case, to the best of our knowledge, of early sacral fracture after a two-level lumbosacral fusion and the only case of early sacral fracture after reduction of spondylolisthesis. CLINICAL PRESENTATION: A patient presented with a sudden recurrence of low back and buttock pain a few days after lumbosacral decompression, reduction of L5-S1 Grade II spondylolisthesis, and instrumented L5-S1 fusion, including posterior lumbar interbody fusion. A transverse sacral fracture was found on plain x-rays 4 weeks later. INTERVENTION: Symptoms improved with brace therapy and medical treatment for osteoporosis. CONCLUSION: Early sacral fracture is a rare cause of pain after instrumented lumbosacral fusion. Although the transfer of loads from rigid spinal implants to adjacent segments is particularly problematic for multisegmental fusions, patients with short-segment constructs may also be affected. Active reduction of spondylolisthesis may provide additional adjacent segment stress contributing to this complication.     

Differences in early sagittal plane alignment between thoracic and lumbar adolescent idiopathic scoliosis

Background contextIt has previously been shown that rotational stability of spinal segments is reduced by posteriorly directed shear loads that are the result of gravity and muscle tone. Posterior shear loads act on those segments of the spine that are posteriorly inclined, as determined by each individual's inherited sagittal spinal profile. Accordingly, it can be inferred that certain sagittal spinal profiles are more prone to develop a rotational deformity that may lead to idiopathic scoliosis; and lumbar scoliosis, on one end of the spectrum, develops from a different sagittal spinal profile than thoracic scoliosis on the other end.PurposeTo examine the role of sagittal spinopelvic alignment in the etiopathogenesis of different types of idiopathic scoliosis.Study design/settingMulticenter retrospective analysis of lateral radiographs of patients with small thoracic and lumbar adolescent idiopathic scoliotic curves.Patients sampleWe included 192 adolescent idiopathic scoliosis patients with either a thoracic (n=128) or lumbar (n=64) structural curve with a Cobb angle of less than 20° were studied. Children with other spinal pathology or with more severe idiopathic scoliosis were excluded, because this disturbs their original sagittal profile. Subjects who underwent scoliosis screening and had a normal spine were included in the control cohort (n=95).Outcome measuresThoracic kyphosis, lumbar lordosis, T9 sagittal offset, C7 and T4 sagittal plumb lines, pelvic incidence, pelvic tilt, and sacral slope, as well as parameters describing orientation in space of each individual vertebra between C7 and L5 and length of the posteriorly inclined segment.MethodsOn standardized lateral radiographs of the spine, a systematic, semi-automatic measurement of the different sagittal spinopelvic parameters was performed for each subject using in-house developed computer software.ResultsEarly thoracic scoliosis showed a significantly different sagittal plane from lumbar scoliosis. Furthermore, both scoliotic curve patterns were different from controls, but in a different sense. Thoracic kyphosis was significantly decreased in thoracic scoliosis compared with both lumbar scoliosis patients and controls. For thoracic scoliosis, a significantly longer posteriorly inclined segment, and steeper posterior inclination of C7–T8 was observed compared with both lumbar scoliosis and controls. In lumbar scoliosis, the posteriorly inclined segment was shorter and located lower in the spine, and T12–L4 was more posteriorly inclined than in the thoracic group. The lumbar scoliosis cohort had a posteriorly inclined segment of the same length as controls, but T12–L2 showed steeper posterior inclination. Lumbar lordosis, pelvic incidence, pelvic tilt, and sacral slope, however, were similar for the two scoliotic subgroups as well as the controls.ConclusionsThis study demonstrates that even at an early stage in the condition, the sagittal profile of thoracic adolescent idiopathic scoliosis differs significantly from lumbar scoliosis, and both types of scoliosis differ from controls, but in different aspects. This supports the theory that differences in underlying sagittal profile play a role in the development of different types of idiopathic scoliosis.     

Profiles of the cervical, thoracic, and lumbosacral spine in children and adolescents with lumbosacral spondylolisthesis.

The sagittal and frontal profiles of the entire spine are poorly studied in lumbosacral spondylolisthesis. It was the purpose of this study to further investigate these profiles. Standing posterior-anterior and lateral radiographs in 24 children with lumbosacral spondylolisthesis were reviewed (18 isthmic, 6 congenital). Cervical lordosis, lumbar lordosis, thoracic kyphosis, sagittal vertebral axis, sacral inclination, slip magnitude, slip angle, and sagittal rotation were measured. Cobb magnitude, Risser sign, curve location, and direction were noted for those with scoliosis. Relationships between sagittal variables were explored (Pearson correlation). The average age of patients was 14.7 +/- 2.5 years, slip magnitude was 38 +/- 38%, slip angle was 5 +/- 31 degrees, sagittal rotation was -6 +/- 31 degrees, thoracic kyphosis was 29 +/- 16 degrees, cervical lordosis was -1 +/- 12 degrees, and lumbar lordosis was 62 +/- 22 degrees. Correlations were noted between thoracic kyphosis and sacral inclination, percent slip, slip angle, and sagittal rotation. Sacral inclination decreased as the slip increased. Scoliosis was present in 10 children, with an average curve of 19 +/- 6 degrees. Thoracic kyphosis was less in those with scoliosis (21 +/- 25 degrees versus 33 +/- 25 degrees, p = 0.033). In children with lumbosacral spondylolisthesis, the sacrum becomes more vertical as the slip worsens. As the sacrum becomes more vertical, the thoracic spine becomes more lordotic, which is likely an adaptive mechanism used by the body to maintain forward visual gaze.     

Sagittal plane configuration of the sacrum in spondylolisthesis

STUDY DESIGN: A radiographic study of the sagittal sacral deformity in spondylolisthesis. OBJECTIVES: To characterize and classify the pathoanatomy of sagittal sacral deformation in spondylolisthesis. SUMMARY OF BACKGROUND DATA: Spondylolisthesis has been extensively described and reviewed in the literature. Deformity of the entire sacrum in spondylolisthesis potentially could affect the natural history, treatment options, and outcome. The sagittal contour of the entire human sacrum has never been quantitatively studied in spondylolisthesis. METHODS: A literature search was performed and data was gathered retrospectively on patients with spondylolisthesis at the authors' institution. Cases of degenerative spondylolisthesis were excluded. Specifically those patients with L5-S1 spondylolisthesis were studied. The authors studied standing lateral radiographs and performed statistical analysis to understand morphologic relations. RESULTS: A broad range of global sacral kyphosis (37-188 degrees ) exists in spondylolisthesis. Increasing sacral kyphosis is significantly associated with increasing percent slip, sacral horizontal angle, Neuman's classification, lumbar lordosis, and lumbar index. A simple classification of the spectrum of sacral deformity in the sagittal plane is presented. CONCLUSION: The entire sacrum in spondylolisthesis can develop a significant kyphotic deformity in the sagittal plane, and this is associated with other abnormalities found in the lumbosacral spine. Sacral deformity is a significant factor in the assessment of the sagittal contour of the patient with L5-S1 spondylolisthesis.     

What is the fate of the adjacent segmental angles 6 months after single-level L3–4 or L4–5 lateral lumbar interbody fusion?

Background ContextLateral lumbar interbody fusion (LLIF) is an effective technique for fusion and sagittal alignment correction/maintenance. Studies have investigated the impact on the segmental angle and lumbar lordosis (and pelvic incidence-lumbar lordosis mismatch), however not much is documented regarding the immediate compensation of the adjacent angles.PurposeTo evaluate acute adjacent and segmental angle as well as lumbar lordosis changes in patients undergoing a L3–4 or L4–5 LLIF for degenerative pathology.Study Design/SettingRetrospective cohort study.Patient SamplePatients included in this study were analyzed pre- and post-LLIF performed by one of three fellowship-trained spine surgeons, 6 months following surgery.Outcome MeasuresPatient demographics (including body mass index, diabetes diagnosis, age, and sex) as well as VAS and ODI scores were measured. Lateral lumbar radiograph parameters: lumbar lordosis (LL), segmental lordosis (SL), infra and supra-adjacent segmental angle, and pelvic incidence (PI).MethodsMultiple regressions were applied for the main hypothesis tests. We examined any interactive effects at each operative level and used the 95% confidence intervals to determine significance: a confidence interval excluding zero indicates a significant effect.ResultsWe identified 84 patients who underwent a single level LLIF (61 at L4–5, 23 at L3–4). For both the overall sample and at each operative level, the operative segmental angle was significantly more lordotic postop compared to preop (all ps≤.01). Adjacent segmental angles were significantly less lordotic postop compared to pre-op overall (p=.001). For the overall sample, greater lordotic change at the operative segment led to more compensatory reduction of lordosis at the supra-adjacent segment. At L4–5, more lordotic change at the operative segment led to more compensatory lordosis reduction at the infra-adjacent segment.ConclusionThe present study demonstrated that LLIF resulted in significant increase in operative level lordosis and a compensatory decrease in supra- and infra-adjacent level lordosis, and subsequently no significant impact on spinopelvic mismatch.