Changes In Sagittal Alignment Research Articles

Sagittal spinal alignment after total hip arthroplasty for neglected high hip dysplasia: does changing the distorted mechanics of the hip normalize spinal alignment?

The false acetabulum lies more laterally and posteriorly compared with the true acetabulum. Spatial orientation of the pelvis is significantly altered in patients with neglected high hip dysplasia. There has been no study to investigate how pelvic or sagittal spinal alignment change after true acetabulum gains function with hip arthroplasty. The aim of this study was to investigate the effect of total hip arthroplasty with femoral shortening on spinopelvic parameters in patients with neglected high hip dysplasia. Twenty patients with Crowe type 3 or 4 hip dysplasia, who underwent total hip arthroplasty with femoral shortening in our institution were evaluated preoperatively after completion of rehabilitation and return to their normal daily life. Sagittal alignment (sacral slope, pelvic incidence, global tilt, segmental lordosis, segmental kyphosis, GAP score) and coronal alignment angles (coronal tilt, Cobb angle) of patients were measured by two independent observers. Twenty patients underwent hip arthroplasty with femoral shortening followed up for a minimum of 12months. We found higher preoperative global lordosis (68.7 ± 9.7) and sacral slope (52.1 ± 8.8) angles, but the pelvic incidences (57.9 ± 10.1) were in the normal range. No statistically significant difference in any sagittal spinopelvic parameters between pre- and postoperative measurements was detected. GAP scores also did not change significantly (p = 0.231). Coronal plane parameters (Cobb angle, coronal pelvic tilt) were the only parameters in which a statistical change was observed (p = 0.02, p = 0.05, respectively). Lumbar lordosis and sacral slope values are outside standard ranges in patients with neglected dysplasia of the hip. The reconstruction of the distorted mechanics of the hip joint does not normalize sagittal pelvic and spine anatomy however improvements in coronal alignment were observed. Disease specific values of sagittal spinal alignment should be used in the treatment of lumbar degenerative problems in patients with neglected high hip dysplasia. IV.

221. Change in sagittal alignment after decompression alone in patients with lumbar spinal stenosis: a prospective cohort study

BACKGROUND CONTEXT Patients with lumbar spinal stenosis present with low back pain, numbness and pain in the legs and gait difficulties due to neurogenic claudication. Patients often walk in a stooped posture to increase the spinal canal diameter by stretching out the ligamentum flavum. This stooped posture leads to a positive sagittal balance. After decompressive surgery, patients may walk in a less stooped manner, improving their sagittal balance, which may lead to less back pain and improved patient reported outcomes. PURPOSE To determine if sagittal balance will improve in patients with spinal stenosis after decompression alone. STUDY DESIGN/SETTING Prospective longitudinal cohort study. PATIENT SAMPLE Patients with lumbar spinal stenosis who underwent decompression alone. OUTCOME MEASURES Oswestry Disability Index (ODI), visual analogue scale (VAS)- leg and back pain. METHODS This study compares preoperative and 6-month postoperative full-length 36” standing lateral and posterior-anterior x-rays and 1-year Oswestry Disability Index (ODI), visual analogue scale (VAS)- leg and back pain, in patients undergoing decompression alone without fusion for central or combined central and lateral stenosis, in patients 60 years and older from March 2016 until September 2017. The following radiographic parameters were measured coronal cobb angle (COBB), pelvic incidence (PI), sagittal vertical axis (SVA), lumbar lordosis (LL), pelvic tilt (PT), pelvic incidence-lumbar lordosis ratio (PI-LL) and sacral slope (SS). RESULTS Forty-five patients (24 males and 21 females) were included. Patients had symptoms for more than 3 months at the time of surgery. Most patients were operated with a bilateral laminectomy over two levels. Sagittal balance showed a statistically significant change in SVA from 65.0mm to 48.6mm (p=0.009) and PI-LL mismatch 7.80 to 4.24 (p= 0.005). A small to moderate association was found between SVA and ODI both preoperatively (r=0.54, p= 0.001) and postoperatively (r=0.51, p= 0.001) and preoperative VAS-leg/back pain (r=0.60, p=0.001)/(r=0.42,p=0.009). CONCLUSIONS There is a statistically significant improvement in sagittal balance in patients undergoing decompression alone for lumbar spinal stenosis. Associations between the SVA and ODI and VAS-leg/back pain indicate that improvements in sagittal balance contribute to improvements in patient reported outcomes. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Hand grip strength as a surrogate marker for postoperative changes in spinopelvic alignment in patients with lumbar spinal stenosis

There are a few studies on the postoperative changes in sagittal alignment and corresponding factors, including hand grip strength (HGS) and muscle performance tests for lumbar spinal stenosis (LSS). Thus, we aimed to determine whether HGS can be a surrogate marker for global sagittal alignment changes after decompression with fusion surgery for LSS. This retrospective observational study included 91 patients who underwent spine fusion surgery for LSS. Radiological spinopelvic parameters, including sagittal vertical axis (SVA), lumbar lordosis (LL), pelvic tilt (PT), pelvic incidence (PI), global tilt (GT), and T1 pelvic angle (T1PA), were analyzed preoperatively and 1 year after posterior decompression and fusion surgery. To assess muscle performance, the 6-m walk (SMT), timed up and go (TUGT), and sit-to-stand (STS) tests were conducted. The relationship between HGS and postoperative SVA was examined through multiple linear regression analysis. Additionally, the relationship between HGS and preoperative/postoperative radiologic spinopelvic parameters and muscle performance test results was analyzed through Pearson's correlation. HGS was significantly correlated with age, preoperative and postoperative SVA, and the muscle performance tests. Furthermore, HGS was a factor that can significantly influence postoperative SVA changes in multiple linear regression analyses. Therefore, HGS may be a good predictor of postoperative SVA change.

Examination of the changes in lower extremities related to progression of adult spinal deformity: a longitudinal study of over 22\xa0years

This longitudinal observational study investigated the relationship between changes in spinal sagittal alignment and changes in lower extremity coronal alignment. A total of 58 female volunteers who visited our institution at least twice during the 1992 to 1997 and 2015 to 2019 periods were investigated. We reviewed whole-spine radiographs and lower extremity radiographs and measured standard spinal sagittal parameters including pelvic incidence [PI], lumbar lordosis [LL], pelvic tilt [PT], sacral slope [SS] and sagittal vertical axis [SVA], and coronal lower extremity parameters including femorotibial angle (FTA), hip–knee–ankle angle (HKA), mechanical lateral distal femoral angle (mLDFA), mechanical medial proximal tibial angle (mMPTA) and mechanical lateral distal tibial angle (mLDTA). Lumbar spondylosis and knee osteoarthritis were assessed using the Kellgren–Lawrence (KL) grading system at baseline and at final follow-up. We investigated the correlation between changes in spinal sagittal alignment and lower extremity alignment and changes in lumbar spondylosis. The mean age [standard deviation (SD)] was 48.3 (6.3) years at first visit and 70.2 (6.3) years at final follow-up. There was a correlation between changes in PI-LL and FTA (R = 0.449, P < 0.001) and between PI-LL and HKA (R = 0.412, P = 0.001). There was a correlation between changes in lumbar spondylosis at L3/4 (R = 0.383, P = 0.004) and L4/5 (R = 0.333, P = 0.012) and the knee joints. Changes in lumbar spondylosis at L3/4 and L4/5 were related to changes in KOA. Successful management of ASD must include evaluation of the state of lower extremity alignment, not only in the sagittal phase, but also the coronal phase.

Degenerative changes of sagittal alignment in patients with Roussouly type 1.

A cross-sectionalradiologicalstudy. We aimed to examine the degenerative changes of sagittal alignment in patients with Roussouly type 1. Roussouly type 1 is unique in shape, characterized by short lumbar lordosis (LL) with the apex at L5 and thoracolumbar kyphosis (TLK). Because of the unique shape of sagittal alignment and the small pelvic incidence (PI) in Roussouly type 1, the degenerative changes of sagittal alignment may differ. A total of 145 patients with Roussouly type 1 were recruited and distributed into three age groups; Group I (N = 40) were young patients (20-40years of age), Group II (N = 47) were middle-aged patients (45-60years of age), and Group III (N = 48) were elderly patients (>65years of age). Sagittal parameters including sagittal vertical axis (SVA), PI, pelvic tilt (PT), L1S1 LL, L4S1 LL, thoracic kyphosis (TK), and TLK were measured using Surgimap® software. The occurrence of lumbar retrolisthesis was also examined. The SVA, PI, PT, L1S1 LL, L4S1 LL, TK, and TLK in group I were - 25.9° ± 23.4mm, 37.1° ± 5.3°, 10.3° ± 5.5°, 42.7° ± 8.8°, 35.5° ± 6.9°, 29.5° ± 23.5°, and 9.7° ± 5.9°, respectively. Among the Groups I, II, and III, there was a stepwise increase in the SVA, PT, TLK, and lumbar retrolisthesis (all P < 0.001). The PI, L4S1 LL, and TK were identical among the three groups. Degenerative changes of Roussouly type 1 include increase in the SVA, PT, TLK, and lumbar retrolisthesis, while the PI, L4S1 LL, and TK remain unchanged. Level IV.

Change of cervical sagittal alignment after the treatment of growing rods to the early-onset scoliosis

Objective: To determine the impact of growing rods (GR) technique on cervical alignment in early-onset scoliosis (EOS) through the change of cervical alignment parameters after the GR surgery. Methods: Total of 24 consecutive EOS patients treated in Beijing Chao-Yang Hospital from 2009 to 2018 were retrospectively reviewed (17 males and 7 females). Cervical lordosis, T(1) slope and C(2-7) sagittal vertical axis (C(2-7)SVA), thoracic/lumbar Cobb angle, thoracic kyphosis (TK), global kyphosis Cobb angle, SVA were included in radiographic data in the full spinal standing X-ray before and post operation and at the last follow-up. Based on clinical data, including the upper instrumented vertebra (UIV), proximal junctional kyphosis (PJK) and the number of GR, patients were divided into different groups for statistical analysis. Logistic regression analysis was used to find the independent risk factors of the abnormality of C(2-7)SVA. Results: All patients received at least one time of distraction operation, the mean follow-up was (35±14) months. The C(2-7) Cobb angle increased from 17°±11° to 18°±9° and T(1) slope changed from 28°±13° to 28°±11° and C(2-7)SVA changed from (17±11) mm to (16±10) mm after the operation, but no significant differences were found in those indexes before and after the operation (t=-1.15, 0.14, 0.55, all P>0.05). At the last follow-up after GR technique, the C(2-7) Cobb angle, T(1) slope angle and C(2-7)SVA significantly increased when compared with those before the operation (t=-7.60, -4.08, -2.46, all P<0.05). The △C(2-7) Cobb angle and △T(1) slope angle PJK group was both more significant than those in non-PJK group (t=3.50, 3.25, both P<0.05); while there was no significant difference in the △C(2-7) Cobb angle and △T(1) slope angle when the choice of UIV and the number of GD were taken into account (t=-1.02, -1.61, -0.67, 0.31, all P>0.05). The occurrence of PJK was identified as an independent risk factor for the abnormality of C(2-7)SVA during the GR surgery with logistic regression analysis(OR=11.57, 95%CI: 1.49-91.54, P<0.05). Conclusions: When used for EOS to correct deformity, GR surgery will increase the cervical lordosis and T(1) slope angle of EOS patients. More attention should be paid to the cervical sagittal alignment and cervical sagittal imbalance in EOS patients with PJK.

Spinal sagittal alignment, spinal shrinkage and back pain changes in office workers during a workday

Purpose. Prolonged sitting is a risk factor for the appearance of lower back pain during work. The aim of this study was to observe changes in spinal sagittal alignment, height and the perception of back pain in office workers during a workday. Materials and methods. Forty-one office workers (20 women) were enrolled into a cross-sectional study. Height, sitting height and degrees of thoracic kyphosis and lumbar lordosis as well as perceived neck pain, lower back pain and upper back pain were determined, before and after an 8-h workday. Results. At the end of the day, workers had a significant decrease (p = 0.000) in height and sitting height, and upper back pain increased significantly (p = 0.023). In men, spinal shrinkage correlated with neck pain (r = 0.410, p = 0.027), and lumbar lordosis degrees in women correlated negatively with upper back pain at the end of the day (r = −0.440, p = 0.012). Conclusions. Spinal shrinkage equally affects men and women who perform the same work. There are no changes in spinal sagittal alignment throughout the workday in office workers. Office workers show significantly increased pain in the upper back at the end of the day.

Sagittal spinopelvic alignment after spinal fusion in degenerative lumbar scoliosis: a meta-analysis

Objective: This meta-analysis aimed to investigate the changes in sagittal spinopelvic alignment in degenerative lumbar scoliosis (DLS) from the preoperative state to the last follow-up.Methods: The MEDLINE via PubMed, Cochrane, Scopus, and Embase databases were searched for studies published between January 2010 and January 2019 evaluating radiological parameters including the coronal Cobb angle, sagittal vertical axis (SVA), thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), and pelvic tilt (PT) in DLS. Two authors performed data extraction independently. All discrepancies were resolved by consensus.Results: The 34 studies identified showed significant decreases in overall and subgroup Cobb angles from the preoperative state to the last follow-up. Both overall TK and LL were significantly increased from the preoperative state to the last follow-up. In subgroup analysis, LLs in the long fusion, combined approach, and posterior approach group were significantly increased at the final follow-up, but the LL increase in the short fusion group was not significant at the last follow-up. However, there was no significant change in SVA, PI, SS, and PT from the preoperative state to the last follow-up.Conclusions: A literature review identified 34 studies reporting preoperative and last follow-up data on spinal fusion in DLS. Despite heterogeneity, a limited meta-analysis showed significant improvement in the coronal Cobb angle, TK, and LL after spinal fusion in DLS. A large, randomized clinical trial would be necessary to validate our results.

The Sagittal Balance of the Cervical Spine: Radiographic Analysis of Interdependence between the Occipitocervical and Spinopelvic Alignment.

Study DesignThis was a prospective clinical study.PurposePrevious studies have indicated that cervical lordosis is a parameter influenced by segmental and global spinal sagittal balance parameters. However, this correlation still remains unclear. Therefore, a better understanding of the normal values and interdependencies between inter-segmental alignment parameters is needed. This is a preliminary analysis that helps to understand these factors.Overview of LiteratureChange in global sagittal alignment is associated with poor health-related quality of life. Questions regarding which parameters play the primary roles in the progression of spinal sagittal imbalance and which might be compensatory factors remain unanswered.MethodsProspectively, 420 adults (105 asymptomatic, 105 cervical symptomatic, 105 lumbar symptomatic, and 105 post-surgical) were selected. Whole-spine standing lateral radiographs were taken, and spinopelvic, thoracic, and cervical parameters were measured. Then, the data were analyzed using correlation coefficient test and multiple regression analysis.ResultsAll the parameters showed a normal distribution. The mean values of the cervical parameters are as follows: C1C2 Cobb angle, −27.07°±4.3°; C2C7 Cobb angle, −16.4°±5.6°; OCC2 Cobb angle, −14.5°±3.8°; OCC7 Cobb angle, −29.8°±5.6°; C2C7 Harrison angle, 20.4°±4.3°; and C7 slope, −25.4°±5.6°. The analysis of these parameters revealed no statistically significant difference between asymptomatic, symptomatic, and post-surgical patients. C7 sagittal vertical axis (SVA) correlated with the C2C7 Cobb angle (r=0.7) in all groups. No significant correlation was noted between cervical and spinopelvic parameters in asymptomatic patients. However, C1C2 Cobb angle correlated significantly with pelvic incidence (PI, r=−0.2), lumbar lordosis (LL, r=0.2), and pelvic tilt (PT, r=−0.2) in cervical symptomatic patients. Irrespective of the patient symptom sub-group (n=420), C1C2 Cobb angle correlated with LL (r=0.1) and C2C7 Harrison angle correlated with PI and PT (r=0.1).Conclusions Our results indicate significant interdependence between the spinopelvic and cervical alignment, especially in cervical symptomatic patients. In addition, strong correlation was found between the C7 SVA and C2C7 Cobb angle. Overall, the results of this study could help to better understand the cervical sagittal alignment and serve as preliminary data for planning surgical reconstruction procedures.

Changes of shoulder balance, sagittal alignments, and curve correction in the treatment of Lenke 1 and 2 adolescent idiopathic scoliosis using a three-dimensional-based correction strategy in correlation to health-related quality of life using the Scoliosis Research Society-22 Questionnaire

Background: Shoulder balance in Lenke 1 and 2 adolescent idiopathic scoliosis (AIS) is a complex condition without a reliable strategy to achieve full correction. Moreover, none reported health-related quality of life of surgically treated Lenke 1 and 2 suffering severe AIS patients before and after the surgery. Subjects and Methods: Preoperative standing, side bend, and postoperative Cobb angles were analyzed to determine the relationship between shoulder balance, curve flexibility, and correction rates. The sagittal alignment was analyzed in these patients by cervical lordosis (CL) (C2–C7), thoracic kyphosis (TK) (T1–T12), lumbar lordosis (LL) (L1-S1), pelvic incidence, pelvis tilt, sacral slope, and C7 sagittal vertical axis (SVA). All recruited patients completed the Scoliosis Research Society-22 questionnaire before, after surgery, and follow-up. Results: There were 26 Lenke 1 and 2 severely AIS patients recruited in this study. The shoulder balance changed from left down to the left up after the operation as reflected by the changes in T1tilt (medial shoulder) and clavicular angles (lateral shoulder). The sagittal alignment changes of this group of patients moved toward increased CL, TK, and LL and an SVA toward zero. “Function” and “Self-image” were significantly improved after surgery, particularly in female Lenke 2 patients regardless of age. Conclusions: The sagittal alignment changes of this group of patients moved toward increased CL, TK, LL and SVA toward zero. “Function” and “Self-image” were significantly improved after the surgery. Sex and age-specific analysis showed that female Lenke 2 AIS patients were the group of patients showing the improvements regardless of age at operation.

Comparison of Spinal Alignment and Mobility in Women With and Without Post Modified Radical Mastectomy Unilateral Lymphoedema

IntroductionUnilateral lymphoedema and breast resection after modified radical mastectomy might create impairment of spinal alignment and mobility. The aim of this study was to compare spinal alignment and mobility in women with and without post modified radical mastectomy unilateral lymphoedema. Materials and MethodsTwenty women with post modified radical mastectomy unilateral lymphoedema (lymphoedema group) and 18 healthy women (control group) were included in this study. The sagittal and frontal spinal alignment and mobility were assessed with a Spinal Mouse (Idiag, Fehraltorf, Switzerland). The severity of the lymphoedema was evaluated with circumferential measurements. ResultsIn the lymphoedema group, the volume difference of the arms was 448.31 ± 78.14 mL, known as moderate severity lymphoedema. It was seen that the sagittal thoracic curvature (P = .017) and the frontal inclination angle (P = .048) were higher in the lymphoedema group in comparison with the control group. In the lymphoedema group, the frontal inclination angle changed towards the unaffected side (P < .001). No significant differences were found between groups in the other parameters related to spinal curvature and mobility (P > .05). ConclusionThe sagittal thoracic curvature and the frontal inclination angle towards the unaffected side increased in women with post modified radical mastectomy unilateral lymphoedema. The sagittal and frontal spinal alignment changes should be taken into consideration for the assessment and the treatment of unilateral lymphoedema.

Spinal shrinkage, sagittal alignment and back discomfort changes in manufacturing company workers during a working day

Prolonged standing and lifting heavy loads are risk factors for the appearance of low back pain in work. The aim of this study was to observe changes in the height, spinal sagittal alignment, and the lumbar and dorsal discomfort perception in assembly line workers. Cross-sectional study, 40 assembly line workers (6 females). Height, sitting height, grades of thoracic kyphosis and lumbar lordosis and perceived spine discomfort, before and after the working day, were determined. Thoracic and lumbar sagittal alignment was compared between discomfort developers and no developers. There was a significant decrease in the height and sitting height of the workers at the end of the day. Thoracic and lumbar curvature increased significantly, as did the perceived lumbar discomfort. Workers on the assembly line, in a prolonged standing work, suffer an increase in lumbar discomfort, and changes in height and thoracic and lumbar curvatures. Practitioner summary: Spinal shrinkage, sagittal alignment and back discomfort (upper and lower back), were analysed in assembly line workers in prolonged standing during a workday. Assembly line workers suffer a decrease in height, an increase in their thoracic and lumbar curvature, and in lumbar discomfort throughout their workday.

Age-related Changes in Cervical Sagittal Alignment

Retrospective cohort study. To identify age-related changes in cervical sagittal parameters using standard radiographs. Cervical sagittal balance is important for the maintenance of neutral head posture and horizontal gaze. Degenerative changes in the cervical spine that occur with aging may alter cervical sagittal balance, which can lead to chronic neck pain and predispose to various cervical spine pathologies. We performed a retrospective cohort study of 151 patients with lateral cervical spine radiographs taken at our institution between December 2017 and June 2018. Cervical sagittal parameters were measured, including C1 inclination, C2 slope, C2-C7 Cobb angle, cervical sagittal vertical axis (cSVA), cervical tilt, upper and lower C7 slopes, T1 slope, and T1 slope minus cervical lordosis (TS-CL). The association between age and cervical sagittal parameters was assessed using the Pearson correlation coefficient and a linear regression analysis. An analysis of variance (ANOVA) with Tukey adjustments was then performed to identify differences in cervical sagittal parameters among patients aged 18 to 39 years, 40 to 64 years, and >64 years of age. There were positive correlations between age and C2-C7 Cobb angle (r = 0.231, P = 0.004), upper C7 slope (r = 0.280, P < 0.001), lower C7 slope (r = 0.283, P < 0.001), and T1 slope (r = 0.189, P = 0.020). Upper C7 slope (R = 0.079) and lower C7 slope (R = 0.074) had the strongest correlation with age in the linear regression analysis. The ANOVA found significant differences among the age subgroups in terms of C2-C7 Cobb angle (P = 0.002), upper C7 slope (P < 0.001), lower C7 slope (P < 0.001), and T1 slope (P = 0.031). Patients >64 years old had significantly higher C2-C7 Cobb angle, upper C7 slope, lower C7 slope, and T1 slope. Changes in cervical sagittal alignment with age are characterized by increased cervical lordosis and increased thoracic kyphosis. 3.

Reciprocal change of sagittal profile in unfused spinal segments and lower extremities after complex adult spinal deformity surgery including spinopelvic fixation: a full-body X-ray analysis

BACKGROUND CONTEXTFew studies have described reciprocal changes of pathologic compensatory mechanisms in the setting of spinopelvic fixation using full-body radiograph. PURPOSETo elucidate how sagittal alignment of unfused spinal segments and lower extremities change reciprocally following complex thoracolumbar realignment surgery including fusion to the sacrum in adult spinal deformity. STUDY DESIGNRetrospective cohort. PATIENT SAMPLEThirty-four patients who underwent fusion from lower thoracic to the sacrum/pelvis and 49 patients with fusion from upper thoracic to the sacrum/pelvis. OUTCOME MEASURESThe postoperative sagittal alignment change, and the correlation between the instrumented spinopelvic alignment change and reciprocal changes in unfused spinal segments/lower extremities. MATERIALS/METHODSThis study included 34 patients who underwent fusion from lower thoracic to the sacrum/pelvis (LT-P group) and 49 patients with fusion from upper thoracic to the sacrum/pelvis (UT-P group). The postoperative sagittal alignment changes were evaluated after subdividing the two groups according to T1 pelvic angle (TPA) (aligned group: TPA<20 and malaligned group: TPA>20). The correlation between the instrumented spinopelvic alignment change (ΔTPA and ΔLL), reciprocal changes in unfused spinal segments and lower extremities, and the cranial sagittal vertical axis-hip/ankle change (ΔCrSVA-Hip/Ankle) were also analyzed. RESULTSAt the baseline in both LT-P and UT-P groups, the patients in the malaligned subgroups showed greater C2–7 lordosis (C2–7L), sacrofemoral angle (SFA), and knee flexion angle (KA) than those in the aligned subgroups. At average 7.1 months postoperatively, these compensatory mechanisms were restored in accordance with instrumented TPA/LL change, especially in the UT-P group. The mid-thoracic alignment changed significantly kyphotic in the LT-P group. ΔTPA and ΔLL linearly correlated with ΔC2–7L, ΔKA, and ΔAA in the malaligned patients. The multivariate regression analysis revealed that change in lower extremity parameters (ΔSFA, ΔKA, and ΔAA) independently impacted ΔCrSVA-Hip/Ankle. CONCLUSIONAdequate thoracolumbar realignment surgery results in restoration of the pathologic compensatory mechanisms in the unfused spinal segments and lower extremities, especially in patients fused from upper thoracic spine. A preoperative clinical evaluation of the lower limb joints, as well as a full-body radiographic evaluation, is paramount to achieve optimal global sagittal balance in thoracolumbar realignment surgery.

Effect of cervical flexion and extension on thoracic sagittal alignment.

The cervical spine has the largest sagittal motion in the whole spine, and cervical alignment affects the thoracic sagittal alignment. However, the effects of cervical flexion and extension on thoracic sagittal alignment have not been investigated in detail. The purpose of this study was to analyze the change of thoracic sagittal alignment following cervical flexion and extension. A total of 55 consecutive patients (42 men and 13 women; average age 49.1 years) who presented to our department with spinal degenerative disease between January 2016 and September 2017 were enrolled in our study. Subjects with a history of trauma, infection, tumor, inflammatory disease, ossification, or cervical deformities, and those who had undergone spinal surgery were excluded. The following parameters were analyzed: occipito-axial angle (O-C2), C2 slope (C2S), C2-C7 angle, T1 slope (T1S), thoracic kyphosis, T1-T4 angle, T5-T8 angle, T9-T12 angle, lumbar lordosis, sacral slope, pelvic tilt in cervical flexion, neutral, and extension. Cervical flexion significantly decreased O-C2, C2-C7 angles and T1S, and increased C2S. Cervical extension conversely changed these parameters. At cervical flexion, the correlation of C2-C7 angle with thoracic parameters was maintained, except for the T1-T4 angle. At cervical extension, the correlation was observed with T1S and T1-T4 angle. Cervical flexion affects the T1S and T5-T8 angle, but there is no significant change in T1-T4 and T9 and lower spino-pelvic columns. This study suggests that T2-T4 can be considered as a stable distal end when cervical long fixation for corrective surgery is performed.

232. Importance of sagittal alignment in cervical spondylotic myelopathy: an observational study from the Canadian Spine Outcomes and Research Network

BACKGROUND CONTEXT Recent evidence suggests that sagittal alignment may play a role in the presentation and management of patients with cervical spondylotic myelopathy (CSM) but its importance has not been fully established. PURPOSE Our objectives were to evaluate the extent to which (1) preoperative sagittal alignment is associated with baseline function and symptoms, (2) surgery leads to changes in sagittal alignment, and (3) postoperative sagittal alignment is associated with function and symptoms at follow-up. STUDY DESIGN/SETTING We performed an observational cohort study using prospectively collected data from the Canadian Spine Outcomes and Research Network (CSORN). PATIENT SAMPLE We included consecutive patients who were diagnosed with CSM by participating surgeons at seven centers between 2015 and 2017. OUTCOME MEASURES mJOA, NDI, VAS, SF12 and EQ5D. METHODS We measured sagittal alignment using two methods: surgeon classification and Ishihara's Cervical Curvature Index (ICCI). We measured function and symptoms with multiple Patient Reported Outcome Measures (PROMs), and we adjusted for age, gender, severity, and comorbidities using multiple linear regression. RESULTS Among 474 patients, baseline alignment was neutral in 196 (41%), lordotic in 190 (40%), and kyphotic in 88 (19%). In unadjusted analyses, baseline kyphosis was associated with significantly worse EuroQol 5D (p CONCLUSIONS In patients with CSM, baseline alignment is not associated with differences in impairment of health-related quality of life after adjusting for potential confounders. Surgery for CSM increases lordosis and improves symptoms and function regardless of baseline alignment, but postoperative sagittal alignment does not seem to be associated with final patient-reported outcomes. Our findings suggest that sagittal alignment restoration may not be critical for improving PROMs in the surgical management of patients with CSM, and that surgeons may prioritize the technical goals of neurological decompression and stabilization. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Changes in Sagittal Alignment Following Short-Level Lumbar Interbody Fusion: Comparison between Posterior and Lateral Lumbar Interbody Fusions.

Study DesignRetrospective case-control study.PurposeWe aimed to compare radiologic outcomes between posterior (PLIF) and lateral lumbar interbody fusion (LLIF) in short-level spinal fusion surgeries.Overview of LiteratureAlthough LLIF enables surgeons to insert large lordotic cages, it is unknown whether LLIF more effectively corrects local and global sagittal alignments compared with PLIF in short-level spinal fusion surgeries.MethodsRadiographic data acquired from patients with lumbar interbody fusion (≤3 levels) using PLIF or LLIF for degenerative lumbar diseases were analyzed. The following radiographic parameters were evaluated preoperatively and at 2 years postoperatively: segmental lordotic angle, disk height, lumbar lordosis (LL), pelvic tilt (PT), C7 sagittal vertical axis, and thoracic kyphosis (TK).ResultsIn total, 144 patients with PLIF (193 fused levels) and 101 with LLIF (159 fused levels) were included. Patients’ backgrounds and preoperative radiographic parameters for any level of fusion did not differ significantly between PLIF and LLIF procedures. The LLIF group exhibited significantly greater changes at 1-level fusion compared to the PLIF group in the parameters of segmental lordotic angle (5.1°±5.8° vs. 2.1°±5.0°, p<0.001), disk height (4.2±2.3 mm vs. 2.2±2.0 mm, p<0.001), LL (7.8°±7.6° vs. 3.9°±8.6°, p=0.004), and PI–LL (−6.9°±6.8° vs. −3.6°±10.1°, p=0.03). While, a similar trend was observed regarding 2-level fusion, significantly greater changes were only observed in LL (12.1°±11.1° vs. 4.2°±9.1°, p=0.047) and PI–LL (−11.2°±11.3° vs. −3.0°±9.3°, p=0.043), PT (−6.4°±4.9° vs. −2.5°±5.3°, p=0.049) and TK (7.8°±11.8° vs. −0.3°±9.7°, p=0.047) in the LLIF group at 3-level fusion.ConclusionsLLIF provides significantly better local sagittal alignment than PLIF in 1- or 2-level fusion cases and improves spinopelvic alignment and local alignment for 3-level fusion cases. Thus, LLIF was demonstrated to be a useful lumbar interbody fusion technique, constituting a powerful tool for achieving sagittal realignment with minimal surgical invasiveness.

How do global sagittal alignment and posture change after total hip arthroplasty?

Postural change after total hip arthroplasty (THA) is still a matter of discussion. Previous studies have mainly concentrated on the pelvic motions. We report the post-operative changes of the global sagittal posture using pelvic, spinal, and lower extremities parameters. 139 patients (primary THA, without previous spinal or lower extremity surgery) were included. We measured pelvic parameters [SS, sacral slope; PI, pelvic incidence; PT, pelvic tilt; APP angle, anterior pelvic plane angle] and the global posture parameters (SVA, sagittal vertical angle; GSA, global sagittal angle; TPA, T1 pelvic angle). Patients were categorized into low PI group < 45°, 45° < medium PI < 65°, and high PI > 65°. Mean GSA and SVA decreased post-operatively (p = 0.005 and p = 0.004 respectively). The TPA change was not significant (p = 0.078). In the low PI group, GSA (5.4 ± 5.0 to 4.3 ± 4.0, p = 0.005) and SVA (5.4 ± 4.9 to 4.2 ± 4.1, p = 0.038) decreased with more posterior pelvic tilt. Post-operative TPA was significantly higher (8.4 ± 10.6 to 9.8 ± 10.7; p = 0.048). In the medium PI group, SVA decreased (4.2 ± 4.6 to 3.6 ± 4.5, p = 0.020) with more posterior pelvic tilt. In the high PI group, pelvic and global posture parameters did not evolve significantly. PI is the key determining factor in pelvic tilt modification after THA. Patients with low PI demonstrate significant modification in spine, pelvic, and lower extremities. Pelvic tilt is the main adaptation mechanism for medium incidence patients whereas pelvic tilt does not change in high PI patients after surgery.

Changes in acetabular orientation during total hip arthroplasty

The aims of this study were to determine the change in pelvic sagittal alignment before, during, and after total hip arthroplasty (THA) undertaken with the patient in the lateral decubitus position, and to determine the impact of these changes on acetabular component position. We retrospectively compared the radiological pelvic ratio among 91 patients undergoing THA. In total, 41 patients (46%) were female. The mean age was 61.6 years (sd 10.7) and the mean body mass index (BMI) was 20.0 kg/m2 (sd 5.5). Anteroposterior radiographs were obtained: in the standing position preoperatively and at six weeks postoperatively; in the lateral decubitus position after trial reduction intraoperatively; and in the supine position in the post-anaesthesia care unit. Pelvic ratio was defined as the ratio between the vertical distance from the inferior aspect of the sacroiliac (SI) joints to the superior pubic symphysis and the horizontal distance between the inferior aspect of the SI joints. Changes in the apparent component position based on changes in pelvic ratio were determined, with a change of > 5° considered clinically significant. Analyses were performed using Wilcoxon's signed-rank test, with p < 0.05 considered significant. Intraoperatively, in the lateral decubitus position, the pelvic ratio increased (anterior tilt) in 69.4% of cases, did not change significantly in 20.4%, and decreased (posterior tilt) in 10.2% of cases. When six-week postoperative radiographs were compared with preoperative radiographs, the pelvic ratio decreased in 44.9% of cases, did not change significantly in 42.3%, and increased in 12.8% of cases. This change in alignment correlated with a change in acetabular component version of > 5° in 79.6% of cases intraoperatively and 57.7% of cases at six weeks postoperatively. Changes in pelvic sagittal pelvic position occur throughout THA that, if unaccounted for, introduce errors in acetabular component placement. The use of intraoperative imaging may help the appropriate placement of the acetabular component. Cite this article: Bone Joint J 2019;101-B(6 Supple B):45-50.

New Strategy for Minimally Invasive Endoscopic Surgery to Treat Infectious Spondylodiscitis in the Thoracolumbar Spine

Background: Eradicating infection, protecting neurologic function, and maintaining structural alignment are the 3 objectives of treatment for infectious spondylodiscitis. For some patients, surgery may be necessary to achieve these goals; however, open surgeries are associated with high morbidity and mortality in elderly patients and those with multiple comorbidities. Endoscopic surgery provides a minimally invasive surgical option for obtaining a culture sample to aid identification of pathogens, while also providing a route for adequate decompression and drainage. The clinical results of this study were analyzed. Objectives: To evaluate the efficacy and safety of spinal endoscopic surgery, the basic characteristics of patients analyzed and their inflammatory markers, pain levels, and local kyphotic angles were recorded before surgery and at regular intervals after surgery. The patients’ cultured pathogens and previous antibiotic treatments were also recorded and analyzed. Study Design: Retrospective observational study (institutional review board: CMUH 105-REC2-101). Setting: Inpatient surgery center. Methods: From October 2006 to March 2017, of 508 patients who received spinal endoscopic surgery, 60 with infectious spondylodiscitis were treated using this new strategy. All 60 patients underwent plain film radiography and enhanced magnetic resonance imaging of the affected region to obtain evidence of infectious spondylodiscitis. The role of a computed tomographyguided biopsy and some indications for open surgery were replaced with endoscopic surgery. Results: All the patients reported rapid pain relief after endoscopic surgery and antibiotic treatment. No significant changes in sagittal alignment were observed in final follow-up radiography images. Causative pathogens were identified in 34 patients (culture rate: 77.27%) without previous antibiotic treatment. The patients’ erythrocyte sedimentation rates and C-reactive protein levels had decreased significantly 3 months after endoscopic surgery. Two patients (3.3%) experienced infection relapse following initial endoscopic surgery; both of them were efficiently resolved through a second round of endoscopic surgery. No surgeryrelated complications were observed and no open spinal surgery was required during the follow-up period. Limitations: This was a retrospective study; bias was unavoidable because of the singlecenter nature of the study design. Conclusions: Regarding the culture rate, recurrence rate, kyphotic change, and surgeryrelated complications, this new strategy for endoscopic surgery is safe and effective for treating infectious spondylodiscitis in the thoracic or lumbar spine and may be considered a new trend in treating diseases of this type. Key words: Spine, endoscopic, discectomy, spondylodiscitis, minimally invasive surgery