Global Spinal Alignment Research Articles

Age-related variations in global spinal alignment and sagittal balance in asymptomatic Japanese adults

Objectives: The global spinal sagittal alignment varies widely among healthy individuals as it is affected by not only race, but also aging. We investigated age-related changes in the spinal alignment in asymptomatic Japanese individuals.Methods: The subjects comprised 220 individuals without any spine-related neurological symptoms or treatment history thereof who visited our outpatient clinic. Lateral radiographs of the whole spine were taken for all subjects in the standing position. Based on the images obtained, spino-pelvic parameters were calculated using Jackson’s method so as to analyze any correlations with age.Results: TIA, TK, and C2–C7A were found to markedly increase with age from late middle age (P < 0.05). No correlation with aging was found for lumbosacral parameters or sagittal balance (P > 0.05). However, there were 22 subjects (10%) with C7SVA > 50 mm, with those aged 70 years or older accounting for half of this subpopulation. Sagittal balance tended to be retained even in elderly subjects if lumbosacral lordosis was large enough to compensate for thoracic kyphosis. A very strong correlation was found between the L1 slope and whole-spine sagittal balance (P < 0.0001, r = −0.497).Conclusions: Increases in cervicothoracic curvature occurring along with thoracic deformation underlie age-related changes in the spine. In contrast, the lumbosacral spine compensates in such a manner so as to maintain the sagittal balance. The whole-spine sagittal balance can deteriorate if the compensatory changes in the lumbosacral spine are insufficient. The L1 slope is a central parameter that defines the whole-spine sagittal balance.Abbreviations: PI; pelvic incidence; SS; sacral slope; PT; pelvic tilt; LL; lumbar lordosis; C7SVA; C7 sagittal vertical axis; SSA; spinosacral angle; TK; thoracic kyphosis; C2–C7SVA; C2–C7 sagittal vertical axis; C2–C7A; C2–C7 Angle; TIA; thoracic inlet angle; NT; neck tilt.

Clinical outcome and global spinal alignment of lower lumbar vertebral fractures after instrumented fusion surgery

Clinical outcome and global spinal alignment of lower lumbar vertebral fractures after instrumented fusion surgery

Predicting Cervical Alignment Required to Maintain Horizontal Gaze Based on Global Spinal Alignment.

A retrospective cohort. The aim of this study was to investigate the cervical alignment necessary for the maintenance of horizontal gaze that depends on underlying thoracolumbar alignment. Cervical Sagittal Curve (CC) is affected by thoracic and global alignment. Recent studies suggest large variability in normative CC ranging from lordotic to kyphotic alignment. No previous studies have assessed the effect of global spinal alignment on CC in maintenance of horizontal gaze. Patients without previous history of spinal surgery and able to maintain their horizontal gaze while undergoing full body imaging were included. Patients were stratified on the basis of thoracic kyphosis (TK) into (<30, 30-40, 40-50, and >50) and then by SRS-Schwab sagittal vertical axis (SVA) modifier into (posterior alignment SVA <0, aligned 0-50, and malaligned >50 mm). Cervical alignment was assessed among SVA grade in TK groups. Stepwise linear regression analysis was applied on random selection of 60% of the population. A simplified formula was developed and validated on the remaining 40%. In each TK group (n = 118, 137, 125, 197), lower CC (C2-C7) was significantly more lordotic by increased Schwab SVA grade. T1 slope and cervical SVA significantly increased with increased thoracolumbar (C7-S1) SVA. Upper CC (C0-C2) and mismatch between T1 slope and CC (T1-CL) were similar. Regression analysis revealed LL minus TK (LL-TK) as an independent predictor (r = 0.640, r = 0.410) with formula: CC = 10- (LL-TK)/2. Validation revealed that the absolute difference between the predicted CC and the actual CC was 8.5°. Moreover, 64.2% of patients had their predicted C2-C7 values within 10° of the actual CC. Cervical kyphosis may represent normal alignment in a significant number of patients. However, in patients with SVA >50 and greater thoracic kyphosis, cervical lordosis is needed to maintain the gaze. Cervical alignment can be predicted from underlying TK and lumbar lordosis, which may be clinically relevant when considering correction for thoracolumbar or cervical deformityLevel of Evidence: 3.

Does spinopelvic alignment affect the union status in thoracolumbar osteoporotic vertebral compression fracture?

In the healing of osteoporotic vertebral fracture, global spinal mal-alignment might increase the load sharing at the fracture site and deteriorate the fracture healing. This study aimed to evaluate the effect of spinopelvic alignment on the union status of thoracolumbar osteoporosis-related vertebral compression fracture (OVCF). Consecutive 48 patients with a single-level thoracolumbar fresh OVCF were treated non-operatively. Union was judged by three independent observers at 6months, and patients were divided into union group and non-union group. Spinopelvic alignment was measured using upright whole spine radiograph before treatment as follows: pelvic incidence (PI), pelvic tilt (PT), lumbar lordosis (LL), thoracic kyphosis (TK), sagittal vertical axis (SVA), and DSVA, defined as the distance from a plumb line dropped from the center of the C7 body to the center of fractured vertebral body. Global spinal alignment was different in union group and non-union group: SVA (4.7±0.7cm in union group vs. 8.9±1.3cm in non-union group, P=0.007), DSVA (4.2±0.6cm in union group vs. 9.5±1.0cm in non-union group, P<0.001), and PI-LL (18.9°±2.2° in union group vs. 30.3°±3.9° in non-union group, P=0.014). Over 5cm of DSVA [P=0.022, adjusted odds 7.9 (95% CI 1.3-77.0)] and/or over 30° of PI-LL [P=0.026, adjusted odds 6.6 (95% CI 1.5-44.2)] showed the significant risk factors for non-union using multivariate logistic regression analysis in the other background status. Global spinal mal-alignment, showing over 5cm of DSVA and/or over 30° of PI-LL, affected the union status of OVCF.

The global alignment in patients with lumbar spinal stenosis: our experience using the EOS full-body images.

Lumbar stenosis is frequently observed and treated by spine surgeons. The extent of neurological decompression and the potential spinal fixation are the basic concerns when surgery is planned. But this segmented approach to the problem is sometimes insufficient due to the complex functional situations induced by a sagittal imbalance of the patient and the combination of pathologies known as hip-spine or knee-spine syndromes. A total of 373 consecutive patients included from our EOS and clinical data base. Patients were divided in two groups. Group A included patients presenting exclusive spinal issues (172 cases) out of whom 117 (68%) had sagittal imbalance. Among 201 patients with associated lower limbs issues (group B), 122 (61%) had sagittal imbalance. The perception of imbalance was noticed in 54% (93 cases) in group A and 57% (115 cases) in group B. In the global series of 239 imbalanced cases, the key point was a spine issue for 165 patients (the 117 patients with only spine problems and 48/122 cases with combined spine and lower limbs problems). But in the patients with combined spine and lower limbs problems, we individualized hip-spine syndromes (24/122 patients) and knee-spine syndromes (13/122 patients). In some cases, (37/122 patients) the anatomical and functional situations were more complex to characterize a spine-hip or a hip-spine problem. The EOS full-body images provide new information regarding the global spinal and lower limbs alignment to improve the understanding of the patient functional posture. This study highlights the importance of the lower limb evaluation not only as compensatory mechanism of the spinal problems but also as an individualized parameter with its own influence on the global balance analysis. Level of evidence IV diagnostic case series.

Operative Management of Post-tumor Spinal Deformity

Introduction The purpose of our research is evaluation of the outcome after surgery and health-related quality of life (HRQOL) parameters in patients with post-tumor spinal deformity. Material and Methods Retrospective clinical and radiographic data were collected for 33 patients (15 male and 18 female, average age of 61.4 years) with spinopelvic malalignments (SRS-Schwab sagittal modifiers: 2 grade and more) who underwent spinal deformity surgery. Patients were divided into two groups. The first group included 13 patients ( n = 12 after chemotherapy of plasmacytoma, n = 1 patient after radiotherapy of cervix uteri cancer metastasis) with confirmed spinal oncology diagnosis by biopsy. All patients have had oncology remission with a 3-year minimum follow-up. Spinal deformity was developed in the period between 1 and 6 years after conservative treatment. Repeated biopsy did not show tumor cells, this was evaluated as local control of tumor. Low scores of HRQOL and unsuccessful nonoperative approach were indications for surgical intervention. The second comparative group consisted of 20 patients with “de novo” degenerative or posttraumatic spinal deformity. The aim of surgical management was to achieve sagittal balance, using osteotomies and transpedicular instrumentalization. Groups were evaluated with HRQOL-scales including VAS, ODI, SF36 and SRS-24. Radiographical assessment included Cobb coronal angle, thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT) and sacral slope (SS), sagittal vertical axis (SVA). Radiographical, HRQOL-parameters and complications were analyzed and compared between two groups. The comparisons were done by using independent sample Student t-test. A p-value of less than 0.05 was accepted as significant. Results Both groups showed a restoration of global spinal alignments without significant differences in TK, LL, PI, PT, SS, SVA parameters (p &gt; 0.05). In addition, HRQOL-scores (VAS, ODI, SF36, SRS-24) of the patients were increased after operation. The HRQOL-scores after 2 years are slightly higher in the first group, but we did not get significant difference between groups (p &gt; 0.05). The number of complications in the form of implant instability, proximal and distal junctional disorders was comparable (p &gt; 0.05). However, general medical complications in the first group was significantly higher than in the second one ( p &lt; 0.05). It is important that no patients had local recurrence or metastasis of tumor during follow-up in the first group. Conclusion Spinal tumor under local control is not contraindication for spinal deformity surgery. Realigning of the sagittal plane is paramount, especially because of the sagittal balance impact on quality of life.

The paraspinal muscles and their role in the maintenance of global spinal alignment. Another wrinkle in an already complex problem

Yagi M, Hosogane N, Watanabe K, Asazuma T, Matsumoto M, Keio Spine Research Group. The paravertebral muscle and psoas for the maintenance of global spinal alignment in patient with degenerative lumbar scoliosis. Spine J 2016:16:451-8 (in this issue).

Degenerative Spinal Deformity.

Degenerative spinal deformity afflicts a significant portion of the elderly and is increasing in prevalence. Recent evidence has revealed sagittal plane malalignment to be a key driver of pain and disability in this population and has led to a significant shift toward a more evidence-based management paradigm. In this narrative review, we review the recent literature on the epidemiology, evaluation, management, and outcomes of degenerative adult spinal deformity (ASD). ASD is increasing in prevalence in North America due to an aging population and demographic shifts. It results from cumulative degenerative changes focused in the intervertebral discs and facet joints that occur asymmetrically to produce deformity. Deformity correction focuses on restoration of global alignment, especially in the sagittal plane, and decompression of the neural elements. General realignment goals have been established, including sagittal vertical axis <50 mm, pelvic tilt <22°, and lumbopelvic mismatch <±9°; however, these should be tailored to the patient. Operative management, in carefully selected patients, yields satisfactory outcomes that appear to be superior to nonoperative strategies. ASD is characterized by malalignment in the sagittal and/or coronal plane and, in adults, presents with pain and disability. Nonoperative management is recommended for patients with mild, nonprogressive symptoms; however, evidence of its efficacy is limited. Surgery aims to restore global spinal alignment, decompress neural elements, and achieve fusion with minimal complications. The surgical approach should balance the desired correction with the increased risk of more aggressive maneuvers. In well-selected patients, surgery yields excellent outcomes.

Comparison of two surgeries in treatment of severe kyphotic deformity caused by ankylosing spondylitis: Transpedicular bivertebrae wedge osteotomy versus one-stage interrupted two-level transpedicular wedge osteotomy

ObjectiveTo explore a simple and effective surgery for correcting severe kyphotic deformity caused by ankylosing spondylitis (AS). Materials and methodsFrom January 2003 to December 2009, we respectively reviewed 32 patients with severe spinal kyphosis caused by AS with at least 2-year follow-up. Patients were divided into two groups, according to surgical methods: transpedicular bivertebrae wedge osteotomy (Group A) or one-stage interrupted two-level transpedicular wedge osteotomy (Group B). We recorded operating time and blood loss. Variation between pre- and post-operative sagittal imbalance, global spinal alignments (Cobb angle of T1 and L5, TLKA), lumbar lordosis, chin-brow vertical angle, thoracolumbar kyphosis angle in both groups were analyzed. ResultsThe average operating time was 236±39min and the average blood loss was 2200±712ml in Group A, and 252±43min, 2202±737ml respectively in Group B. There were no significant differences in operating time and blood loss. Variation between pre- and post-operative sagittal imbalance, global spinal alignments, lumbar lordosis and chin-brow vertical angle (CBVA) were comparable between the two groups. The variation of thoracolumbar kyphosis angle was significantly greater in Group B compared with Group A. SRS-22 scores were similar in the two groups at the 2-year follow-up and significantly improved compared with preoperative. ConclusionsFor correcting severe kyphosis in patients with AS, the one-stage interrupted two-level transpedicular wedge osteotomy is a safe and effective technique which can significantly improve the thoracolumbar kyphosis angle.

Assessment of impact of standing long-cassette radiographs on surgical planning for lumbar pathology: an international survey of spine surgeons.

OBJECT The associations among global spinal alignment, patient-reported disability, and surgical outcomes have increasingly gained attention. The assessment of global spinal alignment requires standing long-cassette anteroposterior and lateral radiographs; however, spine surgeons routinely rely only on short-segment imaging when evaluating seemingly isolated lumbar pathology. This may prohibit adequate surgical planning and may predispose surgeons to not recognize associated pathology in the thoracic spine and sagittal spinopelvic malalignment. The authors used a case-based survey questionnaire to evaluate if including long-cassette radiographs led to changes to respondents' operative plans as compared with their chosen plan when cases contained standard imaging of the involved lumbar spine only. METHODS A case-based survey was distributed to AOSpine International members that consisted of 15 cases of lumbar spine pathology and lumbar imaging only. The same 15 cases were then shuffled and presented a second time with additional long-cassette radiographs. Each case required participants to select a single operative plan with 5 choices ranging from least to most extensive. The cases included 5 "control" cases with normal global spinal alignment and 10 "test" cases with significant sagittal and/or coronal malalignment. Mean scores were determined for each question with higher scores representing more invasive and/or extensive operative plans. RESULTS Of 712 spine surgeons who started the survey, 316 (44%) completed the entire series, including 68% of surgeons with spine fellowship training and representation from more than 40 countries. For test cases, but not for control cases, there were significantly higher average surgical invasiveness scores for cases presented with long-cassette radiographs (4.2) as compared with those cases with lumbar imaging only (3.4; p = 0.002). The addition of long-cassette radiographs resulted in 82.1% of respondents recommending instrumentation up to the thoracic spine, a 23.2% increase as compared with the same cases presented with lumbar imaging only (p = 0.008). CONCLUSIONS This study demonstrates the importance of maintaining a low threshold for performing standing long-cassette imaging when assessing seemingly isolated lumbar pathology. Such imaging is necessary for the assessment of spinopelvic and global spinal alignment, which can be important in operative planning. Deformity, particularly positive sagittal malalignment, may go undetected unless one maintains a high index of suspicion and obtains long-cassette radiographs. It is recommended that spine surgeons recognize the prevalence and importance of such deformity when contemplating operative intervention.

The paravertebral muscle and psoas for the maintenance of global spinal alignment in patient with degenerative lumbar scoliosis

Background contextVarious factors are reported to affect the spinal alignment in degenerative lumbar scoliosis (DLS). Although trunk muscles also appear to affect spinal alignment, the role of the trunk muscles is not yet clear. PurposeThe aim was to elucidate the role of the multifidus (MF) and psoas (PS) in maintaining global spinal alignment in patients with DLS. Study designThis was a multicenter retrospective matched cohort study. Patient sampleSurgically treated 60 paired DLS and lumbar spinal stenosis (LSS) female (120 patients), matched for age and body mass index (BMI; DLS age 68.0±6.8 vs. LSS 67.1±8.9 years; BMI 21.6±3.3 vs. 23.2±3.8 kg/m2), were included and were followed for at least 2 years. Outcome measuresSpinal alignment, muscle area, and volume were measured from radiographs, magnetic resonance images (MRIs), and whole-body dual-energy X-ray absorptiometry (DXA) scans. Muscle strength was measured by grip power and peak expiratory flow (PEF). MethodsAs a surrogate of muscle area, we obtained the cross-sectional area (CSA) at the L5–S level from preoperative MRIs. ResultsThe MF and PS CSAs were significantly smaller in the DLS group than in the LSS group (MF 477.7±192.5 vs. 779.8±248.6 mm2, p<.01; PS 692.3±201.2 vs. 943.4±272.4 mm2, p=.002), whereas percentage of difference between the right and left sides was significantly larger in the DLS group (MF 18.4±30.6 vs. 2.4±3.3%, p<.01; PS 14.4±15.8 vs. 2.1±2.2%, p<.01). In the extremities, there were no significant differences in the left- or right-side lean composition and grip strength or PEF tests between the groups. Correlation coefficient tests showed moderate correlations between the MF average CSA (avCSA) and global spinal alignment and spinopelvic alignment (pelvic incidence-lumbar lordosis; R=−0.37, −0.38) in the DLS group. The MF avCSA was correlated with the postoperative progression of kyphosis at the unfused thoracic vertebrae in the DLS group (R=0.34). ConclusionsThe CSAs of the MF and PS were significantly smaller in the DLS group. Whole-body DXA showed no significant difference in the lean composition between the groups. There were significant correlations in the DLS patients between the MF CSA and sagittal spinal alignment. These findings suggest the causal relationship between muscles and global spine alignment.

Pedicle Subtraction Osteotomy in a 5-Year-Old Child with Congenital Kyphosis.

Vertebral anomalies may also distort the normal regional or global spinal alignment and necessitate some therapeutic interventions. Hemiepiphysiodesis is a traditional procedure usually described for these young patients but in more severe cases some type of osteotomy seems to be necessary. In this technical note, we describe a 5-year-old boy with failed previous hemiepiphysiodesis surgery, who was successfully treated with one level pedicle subtraction osteotomy. This procedure not only corrects the kyphotic deformity at the time of the procedure (not relying on future spinal growth), but also avoids more hazardous anterior approach.

Implant Instability, Proximal Fractures, Quality of Life, and Outcomes of Global Spinal Alignments Correction using Short Fusion in Adults and Elderly

Introduction The purpose of our research is studying of incidence of implant instability, proximal fractures of instrumented and adjacent vertebras, and evaluation of health-related quality of life (HRQOL) parameters depending on extent of the sagittal balance correction after short fusion using a posterior approach. Patients and Methods A study of 83 patients with Type L (SRS-Schwab) deformity, operated in our institute was held in the period between 2008 and 2011. Patients were divided into two groups. The first retrospective group included 43 patients who underwent short fusion of lumbar curve from T12 or L1 to L5. The second prospective group consisted of 40 patients, which were treated using short fusion from T9 to S1 extending to the pelvis. Groups were evaluated with HRQOL-scales including VAS, ODI, SF36, and SRS-24. Radiographical assessment included Cobb coronal angle, thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS), sagittal vertical axis (SVA). Radiographical, HRQOL-parameters and complications with a 3-year minimum follow-up were analyzed and compared between two groups. The comparisons were done by using independent sample Student t-test. A p-value of less than 0.05 was accepted as significant. Results In the first group the ideal sagittal balance was not achieved. The second group showed a better restoration of global spinal alignments compared with the first one ( p &lt; 0.05). The HRQOL-scores (VAS, ODI, SF36, and SRS-24) of the patients after 3 years are slightly higher in the second group, but we did not get significant difference between groups ( p &gt; 0.05). In the first group the number of complications in the form of implant instability ( n = 15, 35%) consists of loosening of screws at the end of fusion (T12/L1 or L4/5). The second group was obtained by a higher number of patients with complications ( n = 25, 63%) including loosening of screws at pelvis ( n = 15, 37.5%), proximal fractures of upper instrumented vertebra ( n = 7, 17.5%) and upper adjacent vertebra ( n = 8, 20%). Incidence of implant instability and proximal fractures in the second group was statistically more frequent ( p &lt; 0.05). Conclusion The research showed that short fusion extending to the pelvis provided good sagittal balance, global spinal alignments, and likely HRQOL-parameters after 3 years follow-up. But, eventually, we obtained higher number of complications.

Assessment of Impact of Long-Cassette Standing X-rays on Surgical Planning for Lumbar Pathology: An International Survey of Spine Surgeons

Introduction Surgical planning to address significant lumbar spine pathology, performed without appreciation of global spinal alignment, may have negative consequences. Our objective was to assess whether the extent of recommended surgery for lumbar pathology would significantly change with the addition of long-cassette standing X-rays. Materials and Methods This was an international online survey of spine surgeons. A series of 15 cases of lumbar spine pathology was presented with a brief clinical vignette and lumbar imaging (X-rays and MRI/CT). Surgeons were asked to select the most appropriate surgical plan, with five choices, ranging from least aggressive (decompression alone; 1 point) to the most aggressive (upper thoracic to sacrum/ilium fusion ± osteotomies/decompression/interbodies; 5 points). Cases were then reordered and presented with long-cassette standing X-rays and the same surgical planning question. Results were compared based on lumbar imaging only versus addition of long-cassette X-rays. Five cases (control group) had normal global alignment and 10 cases (study group) had global malalignment. Results A total of 316 surgeons completed the survey, predominantly (63%) from North America and Europe. Specialties included orthopedic surgery (65%) and neurosurgery (34%), 68% completed spine fellowship, and responders had a mean 13.4 years in practice that was a mean of 76% spine and included a mean of 123 fusions per year. For study cases, extent of recommended surgery increased significantly with the addition of long-cassette X-rays versus lumbar imaging only ( p = 0.002). For control cases with normal global alignment, no significant changes in surgery plans were identified with the addition of long-cassette X-rays ( p = 0.280). Conclusion Long-cassette standing X-rays can have a significant impact on surgical planning for lumbar pathology. Surgeons should maintain a relatively low threshold for obtaining long-cassette standing X-rays when contemplating surgical treatment for significant lumbar spine pathology.

Comparative Analysis of Global Spine Alignment using Whole Spine CT and X-Ray: Correlative Analysis of Reciprocal and Physiologic Changes of the Cervical Alignment

Objective The aims of this study were to compare the parameters of spinal sagittal alignment between whole spine computed tomography (CT) scans in supine position and whole spine X-ray in standing position, and also to analyze the reciprocal and physiologic changes of the cervical spine in dynamic motion. Methods Data were obtained retrospectively in a single hospital. Radiographic data of 55 subjects were recruited about whole spine CT, whole spine X-ray, and cervical dynamic X-ray from November 2007 to May 2014. The mean age was 52.8 year (range, 17–85 years) and the female:male ratio was 31:24. Whole spine CT was checked in supine position and whole spine X-ray was checked in standing position. Cervical dynamic X-ray was checked in standing position. We included the subjects only with mild degenerative disease and simple back pain and excluded the subjects with severe scoliosis, severe deformity, and operation history. The radiological sagittal parameters on lateral paragraph were evaluated including C0–C7 Cobb angle (C0C7), C0–C2 Cobb angle (C0C2), C2–C7 Cobb angle (C2C7), T1 slope (T1S), neck tilt (NT), thoracic inlet angle (TIA), C2 tilt (C2T), C7 tilt (C7T), C2 sagittal vertical axis (C2SVA), C7 sagittal vertical axis (C7SVA), T1–T12 Cobb angle (T1T12), T1–T7 Cobb angle (T1T7), T7–T12 Cobb angle (T7T12), L1–S1 Cobb angle (L1S1), sacral slope (SS), pelvic tilt (PT), and pelvic incidence (PI). Each parameter was analyzed statistically with paired t test between CT and X-ray, and also assessed the relationships between all parameters with the Pearson correlation analysis. Results All corresponding parameters of spine alignment on X-ray were significantly correlated with those on CT. There was no significant difference in TIA (0.62 ± 3.41) and PI (0.62 ± 3.55) between CT and X-ray ( p &gt; 0.05). However, cervical lordosis, T1 slope (T1S), thoracic kyphosis, and lumbar lordosis (L1S1) on X-ray were significantly larger than those on CT. The differences of the means were 21.3 ± 15.6 degrees in C0C7, 3.8 ± 9.5 degrees in C0C2, 17.5 ± 12.3 degrees in C2C7, 7.8 ± 11.3 degrees in T1S, 14.3 ± 9.8 degrees in T1T12, 9.1 ± 8.4 degrees in T1T7, 5.2 ± 9.0 degrees in T7T12, and 4.8 ± 17.1 degrees in L1S1 ( p &lt; 0.05). Age significantly correlated with TIA ( r = 0.382). Thoracic kyphosis (T1T12) had the significant correlation with T1S ( r = 0.874 on CT, r = 0.425 on X-ray) and cervical lordosis (C0C7; r = 0.455 on CT, r = 0.405 on X-ray). Cervical tilt (C2T) and SVA (C2SVA) also had the significant correlations with T1S (C2T: r = − 0.570 on CT, r = − 0.550 on X-ray; C2SVA: r = 537 on CT, r = 0.498 on X-ray). T1S had the significant correlations with the TIA ( r = 0.414 on CT, r = 0.368 on X-ray). T1S also had the significant correlations with cervical lordosis (C0C7: r = 0.367 on CT, r = − 0.469 on X-ray), which mainly correlated with subaxial spine (C2C7: r = 0.355 on CT, r = 0.404 on X-ray) and not with upper cervical spine (C0C2). The changes of the cervical lordosis (C0C7) in dynamic motion (neutral, flexion, and extension) had highly evident correlations with subaxial spine (C2C7) than with upper cervical spine (C0C2). Pearson correlation coefficients ( R) between C0C7 and C2C7 were 0.810 in neural, 0.766 in flexion, and 0.740 in extension, respectively ( p &lt; 0.01). Conclusion The difference of spine alignment between CT and X-ray should be because of the difference of the gravity stem from the posture. Upright posture may increase thoracic kyphosis, and cervical lordosis sequentially and reciprocally. Physiologic motions in the spine cause the cervical accommodations, in which subaxial spine is mainly and initially responsible for the reciprocal changes to other spinal parameters such as TIA and T1 slope. This finding may be the main reason of the subaxial cervical spine degeneration.

Complications and neurological deficits following minimally invasive anterior column release for adult spinal deformity: a retrospective study.

Minimally invasive techniques have become increasing popular and are expanding into deformity surgery. The lateral retroperitoneal transpsoas anterior column release (ACR) is a newer minimally invasive alternative to posterior osteotomy techniques for correcting and promoting global spinal alignment. This procedure attempts to avoid the potential complications associated with conventional osteotomies, but has its own subset of unique complications to be discussed in depth. A retrospective review was performed in all patients who underwent the minimally invasive (MIS) ACR procedure from 2010 to present at our institution. All perioperative and postoperative complications were recorded by an independent reviewer. Demographics, spinopelvic parameters, and operative data were collected. The primary etiologic diagnosis was adult spinal deformity. Spinopelvic parameters were measured based on standing 36-inch scoliosis films. Thirty-one patients underwent a total of 47 MIS-ACRs. The mean age of the cohort was 62. Mean follow up was 12 months (range 3-38 months). The average change from in lumbar lordosis (LL) was 17.6°, in pelvic tilt was 4.3°, coronal Cobb was 13.9 and in SVA was 3.8 cm. Of the 47 MIS-ACR procedures, there were 9 (9/47, 19 %) major complications related to the ACR. Iliopsoas weakness was seen in eight patients and retrograde ejaculation in one patient. Only one patient remained with mild motor deficit at the most recent follow-up. No revision surgeries were required for the anterolateral approach. There was no vascular, visceral, or infectious complications associated with the MIS-ACR. The MIS-ACR is one of the most technically demanding procedures performed from the lateral transpsoas approach. This procedure has the advantage of maintaining and improving spinal global alignment while minimizing blood loss and excessive tissue dissection. It comes with its own unique set of potentially catastrophic complications and should only be performed by surgeons proficient in both deformity correction and the lateral approach.

Analysis of cervical and global spine alignment under Roussouly sagittal classification in Chinese cervical spondylotic patients and asymptomatic subjects.

To explore the relationship between cervical spine and the global spine alignment and to postulate the hypotheses that a lordotic alignment of cervical spine is not the only standard to identify asymptomatic subjects, and the degenerative modification of cervical curves depends primarily on their spinal-pelvic alignment. A cohort of 120 cases of Chinese asymptomatic subjects and a cohort of 121 cases of Chinese cervical spondylotic patients were recruited prospectively from 2011 to 2012. Roussouly Classification was utilized to categorize all subjects and patients according to their thoracic spine, lumbar spine and pelvic alignment. The cervical alignments were evaluated as lordosis, straight, sigmoid or kyphosis. Through the lateral X-ray images of neutral cervical and global spine, a number of parameters were measured and analyzed, including pelvic incidence, pelvic tilt, sacral slope, thoracic kyphosis (TK), lumbar lordosis, global cervical angles (angles between two lines parallel with posterior walls of C2 and C7), practical cervical angles (the addition of different cervical end plate angles from C3 to C7, and inter-vertebral angles from C23 to C67), T1 slope, spinal sacral angles (SSA), Hip to C7/Hip to Sacrum and C0-C2 angle. The percentages of cervical lordosis were 28.3% and 36.4% in asymptomatic and spondylotic group, respectively. The cervical spine alignments correlated with Roussouly types of global spine alignment in both asymptomatic and cervical spondylotic group (P < 0.001). And there were significant differences between Roussouly Type 2 and 4, Type 3 and 4, Type 1 and 3 in cervical angles in spondylotic group (P < 0.05). In the comparison of the two cohorts, significant differences were found in both general and practical cervical angles in Roussouly Type 4 (P = 0.00 and 0.01, respectively), and there were significant differences in inter-vertebral angle in Roussouly Type 2 at C4-5 and C5-6 levels (P = 0.04 and 0.04, respectively), and in Roussouly Type 3 at C6-7 level (P = 0.01). The SSA showed significant difference between Roussouly Type 2 and 4 in asymptomatic subjects (P = 0.00), and between Type 1 and 3, 1 and 4, 2 and 3, 2 and 4 in cervical spondylotic patients (P = 0.01, 0.02, 0.00 and 0.01, respectively). The T1 slope was significantly different among Roussouly types (P = 0.04) with its largest value in Type 1 in cervical spondylotic group. There are significant differences in C0-C2 angles in all Roussouly types (P = 0.01, 0.02, 0.00 and 0.01, respectively), as well as in the ratio of Hip to C7/hip to sacrum in Type 2 (P = 0.01), and Type 3 (P = 0.00) in the comparison of the two cohorts. The multiple linear regression of all parameters showed both general and practical cervical angles were significantly related to TK, C0-C2 and T1 slope (P = 0.01, 0.00 and 0.00, respectively). The cervical alignment correlates with their global spine and pelvic curves. And lordosis is not the only presentation in asymptomatic subjects. The degenerative modification of cervical disc angles was the compensation of global spine degeneration for horizontal gaze. Cervical angles are influenced by their TK angles, occipital-C2 joint and the tilt of T1 vertebral body. The occipital-C2 joint has a compensating mechanism in all Roussouly types in cervical spondylosis.

Does balloon kyphoplasty improve the global spinal alignment in osteoporotic vertebral fracture?

Balloon kyphoplasty (BKP) has been a well-accepted procedure in the treatment of osteoporotic vertebral compression fracture (OVCF), whereas it remains unclear whether or not this procedure has an impact on the global spinal alignment. The purpose of this study is to evaluate the effect of BKP on the global spinal alignment in OVCF. Fifty-six consecutive patients who had undergone BKP for symptomatic OVCF were retrospectively reviewed with a mean follow-up of 32 months. They were seven males and 49 females with a mean age of 75 years. Radiographic assessment was performed using upright whole spine radiographs. The parameters included vertebral kyphosis, mid-vertebral body height and global sagittal spinal alignment (C7 plumb line deviation). Clinical outcomes were evaluated using visual analog scale of back pain. Fifty-one of 56 patients (91.1 %) achieved immediate pain relief. Vertebral kyphosis significantly decreased from 18 to 14 degrees, but 43 patients (76.8 %) still had more than 10 degrees of local kyphosis. Subsequent vertebral compression fractures were observed in seven patients (12.5 %). Anterior deviation of a C7 plumb line (C7PL) was 3.1 cm pre-operatively, 3.1 cm postoperatively, and significantly increased to 5.9 cm at the final follow-up. Consistent results were obtained in those with pre-operative sagittal imbalance (>5 cm anterior deviation of C7PL) and with pre-existing OVCFs. BKP contributed to immediate pain relief, but did not improve the global sagittal spinal alignment after OVCF. This procedure should be solely indicated for painful OVCF or non-union, and could not be expected to restore the global sagittal alignment.

Cervical deformity: Pre-operative evaluation and surgical treatment options

Cervical deformity is a major cause of cervical myelopathy and often leads to poor health-related quality-of-life outcomes. These deformities are complex in nature and require a thorough understanding of the radiographic parameters used to measure the degree of malalignment in order to develop an appropriate pre-operative plan. The magnitude and rigidity of the deformity often dictates whether an anterior, posterior, or combined approach is required to achieve the goals of surgery, which are to decompress the neural elements, as well as reestablish regional and global spinal alignment.

Cervical Radiographical Alignment

Narrative review. To provide a comprehensive narrative review of cervical alignment parameters, the methods for quantifying cervical alignment, normal cervical alignment values, and how alignment is associated with cervical deformity and myelopathy with discussions of health-related quality of life. Indications for surgery to correct cervical alignment are not well-defined and there is no set standard to address the amount of correction to be achieved. In addition, classifications of cervical deformity have yet to be fully established and treatment options defined and clarified. A survey of the cervical spine literature was conducted. New normative cervical alignment values from an asymptomatic volunteer population are introduced, updated methods for quantifying cervical alignment are discussed, and describing the relationship between cervical alignment, disability, and myelopathy are outlined. Specifically, methods used to quantify cervical alignment include cervical lordosis, cervical sagittal vertical axis, and horizontal gaze with the chin-brow vertical angle. Updated methods include T1 slope. Evidence from a few recent studies suggests correlations between radiographical parameters in the cervical spine and health-related quality of life. Analysis of the cervical regional alignment with respect to overall spinal pelvic alignment is emerging and critical. Cervical myelopathy and sagittal alignment of the cervical spine are closely related as cervical deformity can lead to spinal cord compression and tension. Cervical deformity correction should take on a comprehensive approach in assessing global cervical-pelvic relationships and the radiographical parameters that effect health-related quality of life scores are not well-defined. Cervical alignment may be important in assessment and treatment of cervical myelopathy. Future work should concentrate on correlation of cervical alignment parameters to disability scores and myelopathy outcomes. SUMMARY STATEMENTS: STATEMENT 1: Cervical sagittal alignment (cervical SVA and kyphosis) is related to thoracolumbar spinal pelvic alignment and to T1 slope. STATEMENT 2: When significant deformity is clinically or radiographically suspected, regional cervical and relative global spinal alignment should be evaluated preoperatively via standing 3-foot scoliosis X-rays for appropriate operative planning. STATEMENT 3: Cervical sagittal alignment (C2-C7 SVA) is correlated to regional disability, general health scores and to myelopathy severity. STATEMENT 4: When performing decompressive surgery for CSM, consideration should be given to correction of cervical kyphosis and cervical sagittal imbalance (C2-C7 SVA) when present.