Radiological analysis of upper lumbar disc herniation and spinopelvic sagittal alignment

Purpose

A retrospective cross-sectional study was designed to explore the role of spinopelvic sagittal alignment in upper lumbar disc herniation (ULD) development.

Methods

A total of 207 consecutive patients who underwent surgery for single-level lumbar disc herniation [24 with ULD and 183 with lower lumbar disc herniation (LLD)] and 40 asymptomatic volunteers were enrolled. Full-length radiographs of the spine were taken to evaluate pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), thoracic kyphosis (TK), lumbar lordosis (LL), and sagittal vertical axis (SVA). The Roussouly classification was utilized to categorize all subjects according to their sagittal alignment. Spinopelvic parameters and Roussouly classification results were compared between groups.

Results

There were significant differences in PI, SS, PT, LL, and SVA between the ULD, LLD, and control groups. PI in the ULD (40.9°) was significantly lower than in the LLD and control groups (48.8° and 47.6°, respectively). LL was significantly lower in the ULD than in the LLD (?32.4° and ?40°, respectively). There were significant differences between the three groups in Roussouly types. The LLD had a significantly higher proportion (62.6 %) of type 2 lordosis (flat back), and the ULD had a higher proportion (33.3 %) of type 1 lordosis than the other groups.

Conclusions

This study demonstrated the importance of PI and lumbar curvature in the pathogenesis of ULD. The higher prevalence of short LL and long TK with low PI in the ULD group implies that an increased mechanical stress at this level may be one of the risk factors of ULD.

     

Sagittal spinopelvic alignment in adolescent thoracic scoliosis secondary to Chiari I malformation: a comparison between the left and the right curves

Purpose

To investigate whether the sagittal morphology differs between the left and right thoracic curves in patients with Chiari malformation-associated scoliosis (CMS).

Methods

Thirty-four patients with a left thoracic curve constituted the CM-L group, whereas 44 patients with a right thoracic curve were assigned into the CM-R group. Another cohort of 90 age- and gender-matched asymptomatic adolescents was enrolled to serve as the control group. Seven sagittal parameters were evaluated on standing lateral radiographs, including thoracic kyphosis (TK), lumbar lordosis (LL), thoracolumbar junctional kyphosis (TJK), sagittal vertical axis (SVA), pelvic incidence (PI), pelvic tilt (PT) and sacral slope (SS).

Results

Compared to the normal controls, the TK, LL and SS were significantly greater in the CM-L group, along with a significantly decreased PT. Similar changes in SS and PT were also demonstrated in the CM-R group, while the TK and LL were found to be relatively normal compared with the control group. Concerning CMS patients with different curve directions, significantly increased TK and LL were observed in the CM-L group, whereas all three pelvic parameters were similar for the two groups. In addition, no significant differences were noted between the three groups in PI, TJK or SVA. Moreover, the LL was strongly related to the TK and SS in all three groups, but to the PI only in the control and CM-R groups. A significant correlation was also noted between TK and SS in the CM-L group.

Conclusions

Significant differences in sagittal profiles indeed exist between CMS patients and healthy adolescents, as well as between CMS patients with different curve directions. In CMI patients with a left thoracic curve, compensatory alterations appear to occur in LL in response to the increased TK to maintain a balanced posture.     

高低位腰椎椎间盘突出症患者脊柱-骨盆矢状面形态变化

目的 比较高位与低位腰椎椎间盘突出症（LDH）患者脊柱-骨盆矢状面形态学差异，探讨脊柱-骨盆矢状面形态学参数异常与高位LDH发生的关系。方法 纳入2006年1月—2022年1月收治的高位LDH患者53例（高位组），同时期性别、年龄和体质量指数（MBI）匹配的低位LDH患者53例（低位组）及单纯下腰部疼痛的非LDH患者53例（对照组）。在站立位全脊柱侧位X线片上测量3组矢状面平衡（SVA）、胸椎后凸角（TK）、腰椎前凸角（LL）、腰骶前凸角（LSL）、骶骨倾斜角（ST）、骨盆入射角（PI）、骨盆倾斜角（PT）、骶骨倾斜角（SS）等脊柱-骨盆矢状面参数。结果 高位组SVA、TK明显高于对照组，LL、ST、PI、PT及SS明显低于对照组；高位组TK明显高于低位组，LL、ST及PI明显低于低位组；差异均有统计学意义（P<0.05）。高位组L₁/L₂节段患者的LL、ST较L₂/L₃节段患者有下降趋势，但差异无统计学意义（P>0.05）。结论 骨盆水平化导致的胸腰段过度代偿可能是高位LDH发生、发展的机制之一。     

Sagittal spinopelvic alignment in adolescents associated with Scheuermann’s kyphosis: a comparison with normal population

Purpose

Spinopelvic alignment is increasingly considered as a main factor in the energy-efficient posture of the individual in normal and pathological status. However, the spinopelvic characteristics in Scheuermann’s kyphosis (SK) are poorly defined in the literature. The purpose of this study was to determine whether differences of the spinopelvic parameters exist between adolescents with SK and age-matched normal controls.

Methods

In this study, 55 patients with SK and 60 healthy age-matched adolescents were recruited consecutively. Sagittal spinal and pelvic parameters were measured from the standing lateral radiograph, including global kyphosis, thoracic kyphosis (TK), cervical lordosis (CL), lumbar lordosis (LL), pelvic incidence (PI), sacrum slope (SS), pelvic tilt (PT) and sagittal vertical axis (SVA). According to the location of the kyphosis, patients were subdivided into Scheuermann’s thoracic kyphosis (STK) group and Scheuermann’s thoracolumbar kyphosis (STLK) group. The radiographic comparison and correlation analysis were further performed.

Results

SK patients had significantly lower PI and PT than normal controls (32.0° vs. 45.0°, P < 0.001 for PI; 0.2° vs. 11.9°, P < 0.001 for PT). The rate of a negative PT was 41.8 % (22/55) in SK patients, which was remarkably higher than in normal controls (10.0 %, 6/60). The CL, TK and LL were significantly increased in STK group when compared with STLK and control groups. A significant correlation was noticed between TK and CL and also between TK and LL in STK group. Both TK and LL were decreased in STLK patients, and a significant correlation was found between them (r = ?0.687, P < 0.001). A significantly strong correlation was also observed between LL and SS in STLK patients (r = ?0.641; P < 0.001).

Conclusion

Adolescents with SK have a significantly lower PI when compared with age-matched normal controls. Patients with different curve patterns (STK vs. STLK) could have distinct compensatory mechanisms to maintain the sagittal balance.     

Does surgery for Scheuermann kyphosis influence sagittal spinopelvic parameters?

Purpose

To analyze changes in sagittal spinopelvic parameters (SSPs) after surgical treatment of Scheuermann’s Kyphosis (SK).

Methods

We analyzed 20 patients affected by SK and subjected to posterior correction of the kyphosis by facetectomy, Ponte osteotomy, fusion and multilevel instrumentation with pedicle screw system. Four spinal and three pelvic parameters were measured: sagittal vertical axis (SVA), thoracic kyphosis (TK), thoracolumbar kyphosis, lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS) and pelvic tilt (PT). Analysis of changes in postprocedural SSPs compared to preoperative values was performed.

Results

TK passed from 78.6° preoperatively to 45.8° (p = 0.003). LL passed from 74.5° preoperatively to 53.5° (p = 0.01). No significant changes occurred in SVA, SS, PT and PI compared to preoperative values.

Conclusion

We confirm the positive effect of surgery by Ponte osteotomy and posterior spinal fusion on TK and LL in patients with SK. In our experience, pelvic parameters did not change after surgery.

     

Radiological analysis of lumbar degenerative kyphosis in relation to pelvic incidence

Background context

Lumbar degenerative kyphosis (LDK) is characterized by sagittal imbalance resulting from a loss of lumbar lordosis (LL). The pelvic incidence (PI) regulates the sagittal alignment of the spine and pelvis.

Purpose

The purpose of this study is to evaluate the spinopelvic parameters in patients with LDK and to compare them with those of a normal population.

Study design/setting

A cross-sectional study.

Patient sample

The selected patients showed characteristic clinical features of LDK. As control group, asymptomatic volunteers without spinal pathology were recruited.

Outcome measures

Full-length radiographs of the spine in the anteroposterior and lateral planes were taken, extending from the base of the skull to the proximal femur. Pelvic incidence, sacral slope (SS), pelvic tilt (PT), main thoracic kyphosis (TK), thoracolumbar junction (TLJ), LL, and sagittal vertical axis (SVA) were evaluated.

Methods

In terms of PI, the patient and control groups were divided into three groups: low (PI≤45°), middle (45°<PI≤60°), and high PI groups (PI>60°). All the spinopelvic parameters were compared between each group and between the patient and control groups in each group. The correlations between each of the parameters were analyzed.

Results

We evaluated 172 patients with symptomatic LDK and 39 healthy volunteers. The number of LDK patients with low, middle, and high PI groups were 44 (25.6%), 72 (44.8%), and 51 (29.6%), respectively. In the control group, the number of low, average, and high PI patients were 18 (46.2%), 15 (38.5%), and 6 (15.4%), respectively. In the control group, PI determined all spinopelvic parameters except SVA. In the LDK group, PI also determined spinopelvic parameters except for TK and SVA. Lumbar degenerative kyphosis with low PI was associated with pronounced kyphosis in LL and TLJ; LDK with a high PI was associated with relatively preserved lordosis in LL with a flat or lordotic TLJ. In terms of pelvic parameters, low PI showed flattened SS and low PT, whereas high PI showed steep SS and high PT.

Conclusions

The results of this study suggest the importance of the key anatomical parameter, PI, in the determination of sagittal contour in symptomatic LDK patients and normal population. Spinopelvic parameters and pelvic compensatory mechanisms in LDK patients differ according to PI. Identifying the spinopelvic parameters is useful when correcting deformities.     

退变性腰椎侧凸脊柱-骨盆参数测量及临床意义

目的测量退变性腰椎侧凸(degenerative lumbar scoliosis,DLS)患者骨盆-脊柱参数并分析其临床意义。方法选取2006年3月—2014年3月在本院脊柱外科就诊的DLS且有完整影像学资料的患者30例(DLS组)及影像学资料完整的无DLS者30例(对照组),测量2组的骨盆入射角(pelvic incidence,PI)、骨盆倾斜角(pelvic tilt,PT)、骶骨倾斜角(sacrum slope,SS)、腰椎前凸角(lumbar lordosis,LL)、胸椎后凸角(thoracic kyphosis,TK)、矢状位平衡(sagittal vertical axis,SVA)。结果 DLS组的LL值明显小于对照组,差异有统计学意义(P0.05);PT、SVA值明显大于对照组,差异有统计学意义(P0.05)。2组的SS、PI及TK值差异无统计学意义(P0.05)。2组的SS与LL、PT与SVA均有相关性。对照组骨盆参数之间(PI、SS及PT)均有相关性,但DLS组骨盆参数之间均无相关性。对照组中LL与SVA显著相关,但DLS组中LL与SVA无相关性。结论骨盆形态的变化与脊柱的矢状位序列密切相关,DLS患者表现为更小的LL以及更大的SVA。     

腰椎椎管狭窄症患者手术前后脊柱-骨盆矢状位参数变化

目的 研究腰椎椎管狭窄症(LSS)患者手术前后脊柱-骨盆矢状位参数的变化,并分析参数之间的相关性.方法 回顾性分析2015年1月—2015年7月在北京朝阳医院接受腰椎后路减压植骨融合内固定术治疗的63例LSS患者临床资料,选取同期60名健康成年志愿者作为对照组.采用疼痛视觉模拟量表(VAS)评分和Oswestry功能障...     

Relationship between cervical sagittal alignment and health-related quality of life in adolescent idiopathic scoliosis

Purpose

Little information is available on the relationship between cervical sagittal alignment and health-related quality of life (HRQOL) in adolescent idiopathic scoliosis (AIS) patients. The aim of this study was to identify relationships between postoperative cervical sagittal alignment and HRQOL in AIS.

Methods

The study and control groups comprised 67 AIS patients (51 girls and 16 boys). All underwent anteroposterior and lateral plain radiography and completed clinical questionnaires. The radiographic parameters investigated were pre- and postoperative C2–C7 lordosis, C2–C7 sagittal vertical axis (SVA), T1 slope, T1 slope minus C2–C7 lordosis (TS-CL), thoracic kyphosis (TK), lumbar lordosis (LL), pelvic tilt (PT), sacral slope (SS), and pelvic incidence (PI). The Korean version of the SRS-22 questionnaire and the previously validated Short Form-36 (SF-36) outcome questionnaire were administered to evaluate HRQOL at last follow-up visits. Statistical analysis was performed to determine the significances of differences between preoperative and last follow-up radiological findings. In addition, correlations between radiological parameters and clinical questionnaire scores were sought.

Results

Radiological sagittal parameters were found to be significantly increased after surgical correction in terms of C2–C7 lordosis (3.5 ± 11.4), C2–C7 SVA (1.5 ± 6.0), T1 slope (3.5 ± 6.1), and TK (6.0 ± 8.1). However, no significant difference was observed for TS-CL, LL, PT, SS, and PI (P > 0.05). Correlation analysis revealed significant relationships between radiographic parameters and questionnaire scores. Multiple regression analysis was performed to identify predictors of HRQOL, and the results obtained revealed that postoperative T1 slope significantly predicted SRS, PCS, and MCS scores and that postoperative C2–C7 SVA predicted SRS scores.

Conclusions

Changes in cervical sagittal parameters were significant after deformity correction in AIS patients. Correlation analysis revealed significant relationships between postoperative radiographic parameters and HRQOL. In particular, T1 slope and C2–C7 SVA were found to be significant predictors of HRQOL in AIS patient.

     

Simple prediction method of lumbar lordosis for planning of lumbar corrective surgery: radiological analysis in a Korean population

Purpose

This study aimed at deriving a lordosis predictive equation using the pelvic incidence and to establish a simple prediction method of lumbar lordosis for planning lumbar corrective surgery in Asians.

Methods

Eighty-six asymptomatic volunteers were enrolled in the study. The maximal lumbar lordosis (MLL), lower lumbar lordosis (LLL), pelvic incidence (PI), and sacral slope (SS) were measured. The correlations between the parameters were analyzed using Pearson correlation analysis. Predictive equations of lumbar lordosis through simple regression analysis of the parameters and simple predictive values of lumbar lordosis using PI were derived.

Results

The PI strongly correlated with the SS (r = 0.78), and a strong correlation was found between the SS and LLL (r = 0.89), and between the SS and MLL (r = 0.83). Based on these correlations, the predictive equations of lumbar lordosis were found (SS = 0.80 + 0.74 PI (r = 0.78, R ² = 0.61), LLL = 5.20 + 0.87 SS (r = 0.89, R ² = 0.80), MLL = 17.41 + 0.96 SS (r = 0.83, R ² = 0.68). When PI was between 30° to 35°, 40° to 50° and 55° to 60°, the equations predicted that MLL would be PI + 10°, PI + 5° and PI, and LLL would be PI – 5°, PI – 10° and PI – 15°, respectively.

Conclusion

This simple calculation method can provide a more appropriate and simpler prediction of lumbar lordosis for Asian populations. The prediction of lumbar lordosis should be used as a reference for surgeons planning to restore the lumbar lordosis in lumbar corrective surgery.     

Influence of spinal sagittal alignment, body balance, muscle strength, and physical ability on falling of middle-aged and elderly males

Objective

Risk factors for falling in elderly people remain uncertain, and the effects of spinal factors and physical ability on body balance and falling have not been examined. The objective of this study was to investigate how factors such as spinal sagittal alignment, spinal range of motion, body balance, muscle strength, and gait speed influence falling in the prospective cohort study.

Methods

The subjects were 100 males who underwent a basic health checkup. Balance, SpinalMouse^® data, grip strength, back muscle strength, 10-m gait time, lumbar lateral standing radiographs, body mass index, and fall history over the previous year were examined. Platform measurements of balance included the distance of movement of the center of pressure (COP) per second (LNG/TIME), the envelopment area traced by movement of the COP (E AREA), and the LNG/E AREA ratio. The thoracic/lumbar angle ratio (T/L ratio) and sagittal vertical axis (SVA) were used as an index of sagittal balance.

Results

LNG/TIME and E AREA showed significant positive correlations with age, T/L ratio, SVA, and 10-m gait time; and significant negative correlations with lumbar lordosis angle, sacral inclination angle, grip strength and back muscle strength. Multiple regression analysis showed significant differences for LNG/TIME and E AREA with T/L ratio, SVA, lumbar lordosis angle and sacral inclination angle (R ² = 0.399). Twelve subjects (12 %) had experienced a fall over the past year. Age, T/L ratio, SVA, lumbar lordosis angle, sacral inclination angle, grip strength, back muscle strength, 10-m gait time, height of the intervertebral disc, osteophyte formation in radiographs and LNG/E AREA differed significantly between fallers and non-fallers. The group with SVA > 40 mm (n = 18) had a significant higher number of subjects with a single fall (6 single fallers/18: p = 0.0075) and with multiple falls (4 multiple fallers/18: p = 0.0095).

Conclusion

Good spinal sagittal alignment, muscle strength and 10-m gait speed improve body balance and reduce the risk of fall. Muscle strength and physical ability are also important for spinal sagittal alignment. Body balance training, improvement of physical abilities including muscle training, and maintenance of spinal sagittal alignment can lead to prevention of fall.     

A new classification system for degenerative spondylolisthesis of the lumbar spine

Purpose

There is no consensus for a comprehensive analysis of degenerative spondylolisthesis of the lumbar spine (DSLS). A new classification system for DSLS based on sagittal alignment was proposed. Its clinical relevance was explored.

Methods

Health-related quality-of-life scales (HRQOLs) and clinical parameters were collected: SF-12, ODI, and low back and leg pain visual analog scales (BP-VAS, LP-VAS). Radiographic analysis included Meyerding grading and sagittal parameters: segmental lordosis (SL), L1–S1 lumbar lordosis (LL), T1–T12 thoracic kyphosis (TK), pelvic incidence (PI), pelvic tilt (PT), and sagittal vertical axis (SVA). Patients were classified according to three main types—1A: preserved LL and SL; 1B: preserved LL and reduced SL (≤5°); 2A: PI–LL ≥10° without pelvic compensation (PT < 25°); 2B: PI–LL ≥10° with pelvic compensation (PT ≥ 25°); type 3: global sagittal malalignment (SVA ≥40 mm).

Results

166 patients (119 F: 47 M) suffering from DSLS were included. Mean age was 67.1 ± 11 years. DSLS demographics were, respectively: type 1A: 73 patients, type 1B: 3, type 2A: 8, type 2B: 22, and type 3: 60. Meyerding grading was: grade 1 (n = 124); grade 2 (n = 24). Affected levels were: L4–L5 (n = 121), L3–L4 (n = 34), L2–L3 (n = 6), and L5–S1 (n = 5). Mean sagittal parameter values were: PI: 59.3° ± 11.9°; PT: 24.3° ± 7.6°; SVA: 29.1 ± 42.2 mm; SL: 18.2° ± 8.1°. DSLS types were correlated with age, ODI and SF-12 PCS (ρ = 0.34, p < 0.05; ρ = 0.33, p < 0.05; ρ = ?0.20, and p = 0.01, respectively).

Conclusion

This classification was consistent with age and HRQOLs and could be a preoperative assessment tool. Its therapeutic impact has yet to be validated.

Level of evidence

4.

     

Characteristics of Sagittal Alignment in Patients with Severe and Rigid Scoliosis

Objective

There has been increasing concern about the importance of sagittal alignment in the evaluation and treatment of spinal scoliosis. However, recent studies have only focused on patients with mild to moderate scoliosis. To date, little is known about the sagittal alignment in patients with severe and rigid scoliosis (SRS). This study was performed to evaluate the sagittal alignment in patients with SRS, and to analyze how it was altered after corrective surgery.

Methods

In this retrospective cohort study, we included 58 patients with SRS who underwent surgery from January 2015 to April 2020. Preoperative and postoperative radiographs were reviewed, and the sagittal parameters mainly included thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), sacrum slope (SS), and sagittal vertical axis (SVA). The sagittal balance state was evaluated according to whether the PI minus the LL (PI-LL) was less than 9°, and the patients were divided into thoracic hyperkyphosis and normal groups based on whether the TK exceeded 40°. The Student's t test, Pearson's test, and Receiver operating characteristic (ROC) curve analysis were used to compare related parameters between the different groups.

Results

The mean follow-up duration was 2.8 years. Preoperatively, the mean PI was 43.6 ± 9.4°, and the mean LL was 65.2 ± 13.9°. Sixty-nine percent of patients showed sagittal imbalance, and they showed larger TK and LL values and smaller PI and SVA values than those with sagittal balance. Additionally, most patients (44/58) presented with thoracic hyperkyphosis; this group had smaller PI and SVA values than the normal patients. Patients with syringomyelia-associated scoliosis were more likely to present with thoracic hyperkyphosis. The TK and LL values were significantly decreased, and 45% of patients with preoperative sagittal imbalance recovered after surgery. These patients had a larger PI (46.4 ± 9.0° vs 38.3 ± 8.8°, P = 0.003) and a smaller TK (25.5 ± 5.2° vs 36.3 ± 8.0°, P = 0.000) at the final follow-up.

Conclusion

Preoperative sagittal imbalance appears in the majority of SRS patients, accounting for approximately 69% of our cohort. Patients with small PI values or syringomyelia-associated scoliosis were more likely to present with thoracic hyperkyphosis. Sagittal imbalance can generally be corrected by surgery, except in patients with a PI less than 39°. To achieve good postoperative sagittal alignment, we recommend controlling the TK to within 31°.     

Parameters influencing the outcome after total disc replacement at the lumbosacral junction. Part 2: distraction and posterior translation lead to clinical failure after a mean follow-up of 5 years

Purpose

The aim of the second part of the study was to investigate the influence of parameters that lead to increased facet joint contact or capsule tensile forces (disc height, lordosis, and sagittal misalignment) on the clinical outcome after total disc replacement (TDR) at the lumbosacral junction.

Methods

A total of 40 patients of a prospective cohort study who received TDR because of degenerative disc disease or osteochondrosis L5/S1 were invited to an additional follow-up for clinical (ODI and VAS for overall, back, and leg pain) and radiographic analysis (a change in disc height, lordosis, or sagittal vertebral misalignment compared with the preoperative state). Based on the final ODI, patients were retrospectively distributed into groups N (normal: <25 %) or F (failure ≥25 %) for radiographic parameter comparison. A correlation analysis was performed between the clinical and radiological results.

Results

A total of 34 patients were available at a mean follow-up of 59.5 months. Both groups (N = 24; F = 10 patients) presented a significant improvement in overall pain, back pain, and ODI over time. At the final follow-up, higher clinical scores correlated with a larger disc height, increased lordosis, and posterior translation of the superior vertebra, which was also reflected by significant differences in these parameters in the group comparison.

Conclusions

Parameters associated with increased facet joint capsule tensile forces lead to an inferior clinical outcome at mid-term follow-up. When performing TDR, we therefore suggest avoiding iatrogenic posterior translation and overdistraction (and consecutive lordosis).     

Quantification of continuous in vivo flexion–extension kinematics and intervertebral strains

Purpose

Healthy subjects performed lumbar flexion and were assessed by video fluoroscopy to measure the in vivo kinematics of the lower lumbar motion segments.

Methods

Fifteen healthy subjects (8 male, 7 female, 28 ± 10 years) performed lumbar flexion and extension back to neutral while their vertebrae were imaged. The sagittal plane vertebral margins of L3–S1 were identified. Lumbar angle, segmental margin strains, axial displacements, anterior–posterior (A–P) translations, and segmental rotations over the course of flexion were measured.

Results

L4–L5 had the largest posterior margin Green strain (65 %). Each segment displayed more axial displacement than A–P translation. Peak vertebral angulation occurred at approximately 75 % of peak flexion during the extension phase.

Conclusion

L4–L5 exhibited the largest anterior and posterior margin strains (29 and 65 %, respectively). Strains in the disc during in vivo lumbar flexion are due to both angular rotation and linear translation.     

Reciprocal changes in cervical spine alignment after corrective thoracolumbar deformity surgery

Purpose

To identify changes in cervical alignment parameters following surgical correction of thoracolumbar deformity and then assess the preoperative parameters which induce changes in cervical alignment following corrective thoracolumbar deformity surgery.

Methods

A retrospective study of 49 patients treated for thoracolumbar deformity with preoperative planning of an acceptably aligned coronal and sagittal plane in each case. We compared cervical spine parameters in two distinct low [preoperative C7 sagittal vertical axis (SVA) ≤6 cm] and high (preoperative C7 SVA ≥9 cm) C7 SVA groups. Multilinear regression analysis was performed and revealed the relationship between postoperative cervical lordosis and preoperative spinopelvic parameters and surgical plans.

Results

In the lower C7 SVA group, cervical lordosis was significantly increased after thoracic/lumbar deformity correction (p < 0.01). In contrast, the high C7 SVA group showed decreased cervical lordosis postoperatively (p < 0.01). Multilinear regression analysis demonstrated the preoperative parameters (preoperative C2–7 angle, T1 slope, surgical plan for PT and C7 SVA), which determine the postoperative cervical lordosis.

Conclusion

In spinal deformity procedures, preoperative spinal alignment parameters, and surgical plans could affect postoperative cervical spine alignment.     

An increase in height of spinous process is associated with decreased heights of intervertebral disc and vertebral body in the degenerative process of lumbar spine

Purpose

Currently degeneration of the intervertebral disc and joint in the degenerative process of the lumbar spine has mainly attracted the attention, however, there are very few literatures focusing on the height of the spinous process. Our objective was to examine in what generation the change in spinous process height occurs and how the change is involved in the degenerative process of the lumbar spine.

Methods

CT or CT myelography of 1,015 patients, 536 males and 579 females were measured in 6 items, including the heights of the L4 and L5 vertebral bodies, the L4 and L5 spinous processes, the L4/5 intervertebral disc, and the L5/S1 intervertebral disc. All data of the 6 items were analyzed and compared between gender in 5 age groups (40s, 50s, 60s, 70s and 80s).

Results

The results indicated a significant increase in the height of the L4 and L5 spinous process (P < 0.01) in the 60- to 70-year-old group for both genders, and also showed that the L4 and L5 vertebral body height was significantly decreased in the 50- to 60-year-old group (P < 0.01 in males, P < 0.001 in females).

Conclusions

Changes in the spinous process morphology followed degenerative changes of the intervertebral disc and vertebral body in the degenerative process of the lumbar spine. This result may suggest that the morphological change of an increase in the height of the spinous process may be a kind of biological defense reaction to stabilize the intervertebral portion.     

An analysis of radiographic parameters comparison between lumbar spine latericumbent and full-length lateral standing radiographs

Background Context

The lumbar spine latericumbent and full-length lateral standing radiographs are most commonly used to assess lumbar disorder. However, there are few literatures on the difference and correlation of the sagittal parameters between the two shooting positions.

A morphological study of lumbar vertebral endplates: radiographic, visual and digital measurements

Purpose

Clinical observations suggest that endplate shape and size are related to complications of disc arthroplasty surgery. Yet, the morphology of the vertebral endplate has not been well defined. This study was conducted to characterize the morphology of lumbar vertebral endplates and to quantify their morphometrics using radiographic, visual and digital measures.

Methods

A total of 591 vertebral endplates from 76 lumbosacral spines of men were studied (mean age 51.3 years). The shape of the vertebral endplates was classified as concave, flat and irregular, and was evaluated from both radiographs and cadaveric samples. Each endplate was further digitized using a laser scanner to quantify diameters, surface area and concavity for the whole endplate and its components (central endplate and epiphyseal rim). The morphological characteristics and morphometrics of the vertebral endplates were depicted.

Results

In both radiographic and visual assessments, more cranial endplates (relative to the disc) were concave and more caudal endplates were flat at all disc levels (p < 0.001). On average, the mean concavity depth was 1.5 mm for the cranial endplate and 0.7 mm for the caudal endplate. From L1/2 down to L5/S1 discs, the vertebral endplate gradually changed into a more oval shape. The central endplate was approximately 70 % of the diameter of the whole endplate and the width of the epiphyseal rim varied from 3 to 7 mm.

Conclusions

There is marked morphological asymmetry between the two adjacent endplates of a lumbar intervertebral disc: the cranial endplate is more concave than the caudal endplate. The size and shape of the vertebral endplate also vary considerably between the upper and lower lumbar regions.     

Influence of transforaminal lumbar interbody fusion procedures on spinal and pelvic parameters of sagittal balance

Introduction

Restitution of sagittal balance is important after lumbar fusion, because it improves fusion rate and may reduce the rate of adjacent segment disease. The purpose of the present study was to describe the impact of transforaminal lumbar interbody fusion (TLIF) procedures on pelvic and spinal parameters and sagittal balance.

Materials and methods

Forty-five patients who had single-level TLIF were included in this study. Pelvic and spinal radiological parameters of sagittal balance were measured preoperatively, postoperatively and at latest follow-up.

Results

Age at surgery averaged 58.4 (±9.6) years. Mean follow-up was 35.1 months (±4.1). Twenty-nine percent of the patients exhibited anterior imbalance preoperatively, with high pelvic tilt (17.6° ± 7.9°). Of the 32 (71%) patients well balanced before the procedure, 22 (70%) had a large pelvic tilt (>20°), due to retroversion of the pelvis as an adaptive response to the loss of lordosis. Three dural tears (7%) were reported intraoperatively. Interbody cages were more posterior than intended in 27% of the cases. Disc height and lumbar lordosis at fusion level significantly increased postoperatively (p < 0.05 and p < 0.001). Pelvic tilt was significantly reduced (p < 0.01) postoperatively, whereas the global sagittal balance was not significantly modified (p = 0.07).

Conclusion

Single-level circumferential fusion helps patients reducing their pelvic compensation, but the amount of correction does not allow for complete correction of sagittal imbalance.