C7 Plumb Line Research Articles

Relationship between hip joint proximity area and sagittal balance parameters: an upright computed tomography study

PurposeA close relationship between sagittal spinal alignment and hip osteoarthritis (OA) has been documented. This study aimed to examine the relationship between hip joint proximity area and sagittal balance parameters in healthy subjects.MethodsThis prospective study enrolled 47 healthy volunteers who underwent 320-detector row upright computed tomography. Acquired data were reconstructed in a virtual three-dimensional space. The proximity area was determined by < 1 mm of the Hausdorff distance between the acetabulum and the femoral head. Volunteers were divided into the anterior and posterior proximity groups depending on the position of the closest area. Sagittal balance parameters [sagittal vertical axis (SVA), T1 spinopelvic inclination (T1-SPi), T1-pelvic angle, pelvic tilt, sacral slope, pelvic incidence, lumbar lordosis, thoracic kyphosis), offset distance between the centre of the acoustic meati (CAM) and C7 plumb line (CAM-C7-offset), and offset distance between the CAM and hip axis (HA) (CAM-HA-offset)] were compared between the two groups using independent sample t test.ResultsThe anterior proximity group (n = 24) had higher SVA (p = 0.016) and T1-Spi (p = 0.015) than the posterior proximity group (n = 23). CAM-HA-offset was higher in the posterior than in the anterior proximity group (p < 0.000). There was no difference in other parameters (p > 0.05).ConclusionThe anterior proximity group had a positive anterior spinal balance; the posterior proximity group may have a more posterior gravity line than the hip joint centre. The anterior spinal balance may contribute to the anterior loading of the hip joint, with known relation with the initiation and onset of hip OA.

Directionality of Lumbosacral Fractional Curve Relative to C7 Plumb Line, A Novel Index Associated with Postoperative Coronal Imbalance in Patients with Degenerative Lumbar Scoliosis.

Retrospective case-control radiographic study. The aim of this study was to explore whether directionality of lumbosacral fractional curve relative to C7 plumb line (PL) affected postoperative coronal imbalance in patients with degenerative lumbar scoliosis (DLS). The spatial relationship between lumbar main curve and C7 PL was reported to have impact on postoperative coronal imbalance in DLS. Although fractional curve played more important role than lumbar main curve in DLS, the spatial relationship between fractional curve and C7 PL and their impact on the postoperative coronal balance are still unknown. One hundred one DLS patients treated with posterior instrumented fusion were reviewed. Coronal measurements included C7 migration, fractional curve, L4/L5 coronal tilt, major Cobb angle. Based on directionality of fractional curve (orientation of L4 coronal tilt was used to represent it) relative to C7 PL preoperatively, coronal patterns was separated into: consistency pattern, L4 coronally tilts toward C7 PL; opposition pattern, L4 coronally tilts opposite C7 PL; the distributions of these two patterns and Type A, B,C were analyzed. According to postoperative C7 migration, patients were divided into imbalanced group and balanced group. Compared to balanced group, the imbalanced group had higher percentage of preoperative consistency pattern (80.6% vs. 33.8%, P < 0.001) and Type C (36.1% vs. 7.7%, P < 0.001); larger fractional curve or L4 coronal tilt pre- and postoperatively, larger L5 coronal tilt postoperatively. Logistic regression analysis showed predictors for postoperative coronal imbalance were consistency pattern (odds ratio [OR] 5.103, 95% confidence interval [CI]: 1.660-15.687, P = 0.004) and type C (OR 4.061; 95% CI: 1.056-15.618; P = 0.041). Directionality of fractional curve relative to C7 PL was associated with postoperative coronal imbalance in DLS patients. In addition to type C, consistency pattern might be an independent risk factor for postoperative coronal imbalance.Level of Evidence: 3.

Mid-term results of a modified self-growing rod technique for the treatment of early-onset scoliosis.

To report the mid-term results of a modified self-growing rod (SGR) technique for the treatment of idiopathic and neuromuscular early-onset scoliosis (EOS). We carried out a retrospective analysis of 16 consecutive patients with EOS treated with an SGR construct at a single hospital between September 2008 and December 2014. General demographics and deformity variables (i.e. major Cobb angle, T1 to T12 length, T1 to S1 length, pelvic obliquity, shoulder obliquity, and C7 plumb line) were recorded preoperatively, and postoperatively at yearly follow-up. Complications and revision procedures were also recorded. Only patients with a minimum follow-up of five years after surgery were included. A total of 16 patients were included. Six patients had an idiopathic EOS while ten patients had a neuromuscular or syndromic EOS (seven spinal muscular atrophy (SMA) and three with cerebral palsy or a syndrome). Their mean ages at surgery were 7.1 years (SD 2.2) and 13.3 years (SD 2.6) respectively at final follow-up. The mean preoperative Cobb angle of the major curve was 66.1° (SD 8.5°) and had improved to 25.5° (SD 9.9°) at final follow-up. The T1 to S1 length increased from 289.7 mm (SD 24.9) before surgery to 330.6 mm (SD 30.4) immediately after surgery. The mean T1 to S1 and T1 to T12 growth after surgery were 64.1 mm (SD 19.9) and 47.4 mm (SD 18.8), respectively, thus accounting for a mean T1 to S1 and T1 to T12 spinal growth after surgery of 10.5 mm/year (SD 3.7) and 7.8 mm/year (SD 3.3), respectively. A total of six patients (five idiopathic EOS, one cerebral palsy EOS) had broken rods during their growth spurt but were uneventfully revised with a fusion procedure. No other complications were noted. Our data show that SGR is a safe and effective technique for the treatment of EOS in nonambulatory hypotonic patients with a neuromuscular condition. Significant spinal growth can be expected after surgery and is comparable to other published techniques for EOS. While satisfactory correction of the deformity can be achieved and maintained with this technique, a high rate of rod breakage was seen in patients with an idiopathic or cerebral palsy EOS. Cite this article: Bone Joint J 2020;102-B(11):1560-1566.

Orientation of L4 coronal tilt relative to C7 plumb line as a predictor for postoperative coronal imbalance in patients with degenerative lumbar scoliosis

The study design is case–control. To evaluate the impact of preoperative coronal patterns based on the relationship between orientation of L4 coronal tilt and C7 plumb line on immediate postoperative coronal imbalance in degenerative lumbar scoliosis (DLS) patients. Although lumbosacral fractional curve has been long stressed in correction surgery of DLS, there is paucity of literature focusing on preoperative coronal pattern based on the relationship between orientation of L4 coronal tilt and C7 plumb line and its impact on immediate postoperative coronal imbalance in DLS patients. A consecutive series of DLS patients who underwent deformity correction surgery via posterior-only approach were reviewed. According to the relationship between orientation of L4 coronal tilt and C7 plumb line preoperatively, a total of 77 DLS patients who underwent posterior spinal corrective surgery were classified into: 1. Coronal consistency pattern, L4 coronally tilts toward C7 plumb line; 2. Coronal opposition pattern, L4 coronally tilts opposite C7 plumb line. Coronal imbalance was defined as global coronal malalignment (GCM) on either side more than or equal to 20 mm. Whole-spine standing radiographs of both pattern groups were assessed preoperatively and postoperatively. There were 37 patients with coronal consistency pattern and 40 patients with coronal opposition pattern. Compared to patients with coronal opposition pattern, patients with coronal consistency pattern had significantly higher postoperative GCM (P = 0.028), lower amount of GCM correction (P = 0.013) and higher incidence of postoperative coronal imbalance (P = 0.001); further logistic regression analysis revealed coronal consistency pattern was associated with increased odds of postoperative coronal imbalance (odds ratio: 5.981; 95% confidence interval 2.029–17.633; P = 0.001). DLS patients with preoperative coronal consistency pattern carried greater risk for immediate postoperative coronal imbalance following posterior long correction surgery.Level of evidence 3

Efficacy and radiographic analysis of oblique lumbar interbody fusion in treating lumbar degenerative spondylolisthesis with sagittal imbalance.

The aim of this study was to evaluate the effectiveness of OLIF (oblique lumbar interbody fusion) in the treatment of lumbar degenerative spondylolisthesis with sagittal imbalance. Fifty-nine patients were included in our analysis. Included patients were divided into 2 groups according to the surgical techniques: PLIF (posterior lumbar interbody fusion) (n = 31) and OLIF + PSF (OLIF combined with posterior spinal fixation) (n = 28). Perioperative radiographic parameters, complications, and clinical outcome from each group were assessed and compared. The operation time for both groups was 165.1 min in the OLIF group and 182.1 min in the PLIF group (P < 0.05). The intraoperative blood loss was 190.6 ml in the OLIF group and 356.3 ml in the PLIF group (P < 0.05). The number of intraoperative and postoperative complications for both groups was 7 in the OLIF group and 11 in the PLIF group. Significant clinical improvement was observed in VAS scores and ODI when comparing preoperative evaluation and final follow-up. The preoperative SVA (the distance from the posterosuperior corner of S1body to the C7 plumb line), PI (pelvic incidence), LL (lumbar lordosis), PI-LL mismatch, DH (disc height), and lumbar Cobb angles of both groups were similar. The postoperative and final follow-up SVA, LL, PI-LL mismatch, and disc height were improved in both groups, and a statistical difference was found between both groups (P < 0.05). An improvement of SVA, LL, PI-LL mismatch, and disc height at the OLIF group was better than that found at the PLIF group. An improvement in radiographic and clinical outcomes for the OLIF group was better than that seen for the PLIF group. Then, OLIF had a more curative effect in lumbar degenerative spondylolisthesis with sagittal imbalance.

Factors related to postoperative coronal imbalance in adult lumbar scoliosis.

The object of this study was to analyze the prevalence of postoperative coronal imbalance (CIB) and related factors in patients with adult lumbar scoliosis. This was a retrospective single-center study of data from patients with adult spinal deformity (ASD) who had undergone corrective surgery performed by a single surgeon between 2009 and 2017. The inclusion criteria were as follows: 1) age at surgery > 40 years, 2) Cobb angles of the thoracolumbar/lumbar (TL/L) curve > 40°, 3) upper instrumented vertebra of T9 or T10, 4) lowest instrumented vertebra of L5 or the pelvis, and 5) minimum 2-year follow-up period. Radiographic parameters were measured before surgery, 2 weeks after surgery, and at the latest follow-up. Curve flexibility was also assessed using side bending radiographs. Clinical outcomes were evaluated using the 22-Item Scoliosis Research Society Outcomes Questionnaire (SRS-22) and the SF-36. CIB was considered to have occurred if the C7 plumbline was more than 2.5 cm lateral to the central sacral vertical line (i.e., coronal vertical axis [CVA] > 2.5 cm) at the final follow-up. Parameters between the patients with (CIB group) and without (coronal balance [CB] group) CIB were compared, and factors related to CIB were evaluated. From among 66 consecutively treated ASD patients, a total of 37 patients (mean age at surgery 66.3 years, average follow-up 63 months) met the study inclusion criteria. CIB was found in 6 patients at the final follow-up (16.2%), and the CVA of all patients in the CIB group shifted to the convex side of the TL/L curve. A comparative analysis between the CB and CIB groups, respectively, at the final follow-up indicated the following factors were related to CIB: lumbosacral (LS) curve, 11.0°/16.5° (p = 0.02); LS correction rate (CR), 61%/47% (p = 0.02); and CR ratio (LS vs TL/L), 0.93/0.67 (p = 0.0002). Regarding clinical outcomes, the satisfaction domain of the SRS-22 (CB 4.4 vs CIB 3.5) showed a significant difference between the CIB and CB groups (p = 0.02), and patients in the CB group tended to score better on the pain domain (CB 4.3 vs CIB 3.7), but the difference was not significant (p = 0.06). Postoperative CIB negatively impacted patients' HRQOL. An imbalanced correction ratio between the TL/L and LS curves may cause postoperative CIB. Therefore, adequate correction of the LS curve may prevent postoperative CIB.

30. Retrospective comparative analysis of combined vs only posterior approach for treating severe scoliosis

BACKGROUND CONTEXT Studies comparing two-stage approach (first anterior then posterior) and only posterior approach for treating scoliosis are rather scarce, with shorter follow-up and lack of clinical data. PURPOSE The purpose of the retrospective study was to compare long-term clinical and radiological outcomes in comparable groups of patients when using different surgical approaches (two-stage and only posterior) for idiopathic scoliosis operations. STUDY DESIGN/SETTING A retrospective, one center, institutional review board approved study. PATIENT SAMPLE A total of 348 patients with idiopathic scoliosis were operated on using CD hybrid instrumentation with pedicle screw and hooks. Only patients with curvatures ≥61 ° were analyzed and divided in two groups: two-stage surgery (N=30) and one-stage surgery (N=46). OUTCOME MEASURES Not applicable. METHODS Comparisons between groups were made regarding the following variables: gender, age at surgery, follow-up duration, number of segments, duration of surgery, hospitalization time, and different radiological parameters. The anteroposterior (AP) and lateral standing radiographs were used to check for deformity; numbers of instrumented segments, curve flexibility (bending test), coronal and sagittal balance and rotation deformity. The coronal balance was measured as the distance between the C7 plumb line and the perpendicular line drawn from the center of S1. The sagittal balance was measured as shortest distance between the C7 plumb line and the posterior superior corner of the S1 body. For both coronal and sagittal measurements, balance was considered abnormal if the distance was greater than 2 cm. Measurement of vertebral rotation was done using the Nash-Moe method. All patients were invited in an outpatient clinic to fill out a short-form health survey (SF-36) and to make a control X-ray image of the whole spine. RESULTS No statistically significant difference was observed in correction between two-stage group (average correction 69%) and only posterior approach group (average correction 66%). However, there were statistically significant differences regarding hospitalization time, duration of the surgery and the number of instrumented segments. The SF-36 scores were similar and there were no statistically significant differences between different health dimensions among compared groups. The greatest differential found in mean scores was for energy and vitality. CONCLUSIONS Two-stage surgery has only a limited advantage in terms of postoperative correction angle compared to the posterior approach. Posterior instrumentation and correction is satisfactory, especially taking into account that the patient is subjected to only one surgery. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

217. Outcomes of surgical treatment for patients with mild scoliosis and age appropriate sagittal alignment with minimum 2-year follow up

BACKGROUND CONTEXT Operative treatment of adult spinal deformity (ASD) can be very challenging with high complication rates. Despite these challenges it's well established that pts benefit from such treatment. However, the surgical outcomes for pts with mild scoliosis and age appropriate sagittal alignment have not been reported. PURPOSE To determine if patients (pts) with mild scoliosis and age appropriate sagittal alignment have favorable outcomes following surgical correction. STUDY DESIGN/SETTING Retrospective review of a prospective, multicenter ASD database. PATIENT SAMPLE ASD patients: operative pts age≥18, and all preoperartive pelvic tilt (PT), mismatch between pelvic incidence and lumbar lordosis (PI-LL), and C7 sagittal vertical axis (SVA) within established age adjusted parameters with minimum 2-year follow up. A subanalysis for pts with max coronal cobb angle 10-30° (mild scoli) was done. OUTCOME MEASURES Health-related quality of life (HRQOL) scores: Oswestry Disability Index (ODI), Short form-36(SF36), Scoliosis Research Society (SRS22), back/leg pain numerical rating scale (NRS) and minimum clinically important difference (MCID)/substantial clinical benefit (SCB). Radiographic values: max coronal cobb angle, coronal C7 plumb line, PT, PI-LL, thoracic kyphosis (TK), SVA. Demographic, frailty, surgical and complications data were collected. METHODS Two-year and baseline HRQOL/radiographic data were compared. RESULTS A total of 103 pts were included from 667 operative patients (89.3% female, avg age 59.8±13.1yrs). Of the 103 pts, 29 (28.2%) had max preop coronal cobb angle 10-30°. Two-year max coronal cobb angle and C7 coronal plumb were significantly improved compared to baseline (p CONCLUSIONS Pts with mild scoliosis and sagittal alignment within age appropriate parameters benefit from surgical correction at 2 years postop both radiographically and clinically including 81.5% meeting MCID for SRS pain despite having high complication rates. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Sagittal Spinopelvic Translation Is Combined With Pelvic Tilt During the Standing to Sitting Position: Pelvic Incidence Is a Key Factor in Patients Who Underwent THA

BackgroundSagittal spinopelvic translation (SSPT) is the horizontal distance from the hip center to the C7 plumb line (C7PL). SSPT is an important variable showing the overall patient balance in different functional positions which could affect the rate of hip instability. This study investigates the SSPT modification in patients who underwent total hip arthroplasty (THA). MethodsA total of 120 patients were assessed preoperatively and postoperatively on standing and sitting acquisitions (primary unilateral THA without complication). SSPT is zero when the C7PL goes through the center of the femoral heads and positive when the C7PL is posterior to the hips’ center (negative if anterior). Three subgroups were defined based on the pelvic incidence (PI): low PI <45°, 45°< normal PI <65°, or high PI >65°. ResultsThe overall mean preoperative SSPT change from standing to sitting was 2.2 cm ([-7.2 to 17.4]) (P < .05). The overall mean postoperative SSPT change from standing to sitting was 1.2 cm ([-14.2 to 22.4]) (P < .05). In low- and normal-PI groups, standing to sitting SSPT and preoperative to postoperative changes in standing SSPT were increased significantly after surgery with the C7PL behind the hips’ center (P < .05). In the high-PI group, standing to sitting SSPT was increased postoperatively (P = .034) (no significant changes from preoperative to postoperative status in standing and sitting). ConclusionsAdaptation from standing to sitting positions combines pelvic tilt and anteroposterior pelvic translation. THA implantation induces significant changes in SSPT mainly for low- and standard-PI patients. This is an important variable to consider when investigating the causes of THA subluxation or dislocation.

The Impact of Posterior Spinal Fusion (PSF) on Coronal Balance in Adolescent Idiopathic Scoliosis (AIS): A New Classification and Trends in the Postoperative Period.

One of the primary goals of scoliosis surgery is to balance the head over the pelvis (or avoid creating imbalance). Historically, a normal coronal balance was defined as the C7 plumb line (C7PL) within 2 cm of the central sacral vertical line (CSVL); however, there is limited published information regarding the speed/magnitude and success/failure of balancing, rebalancing, or unbalancing in the postoperative period. The purpose of this study is to classify and quantify coronal plane balance postoperatively in adolescent idiopathic scoliosis when using pedicle screw instrumentation. Evaluated patients with adolescent idiopathic scoliosis who had a posterior spinal fusion withstanding 2-view, posteroanterior and lateral radiographs of the entire spine performed at first erect visit, 6, 12, and 24 months. To measure coronal balance, a C7PL was measured and compared with the CSVL. A negative value denotes the leftward deviation of the C7PL and a positive value a rightward deviation. The authors then created a novel coronal balance classification system. A total of 954 patients met the inclusion criteria. There was a strong trend toward improving coronal balance, especially between first erect and 6 months; the proportion of out of balance patients declined throughout the 2-year period: preoperative 372 of 954 (39%), first erect 297 of 954 (31.1%), 6 months 167 of 954 (17.5%), 1 year 136 of 954 (14.3%), and 2 years 115 of 954 (12.0%). Analyzing the patients most out of balance immediately after posterior spinal fusion, 35 of 50 (70%) in group 3 regained balance by 2 years. Out of the remaining 15 patients, 12 corrected to group 1 (24%), 2 patients to group 2 (4%), and 1 patient remained in group 3 (2%). This large, longitudinal postoperative study of coronal balance documents a strong trend toward postoperative rebalancing, with the largest gains between first erect image and 6 months. The 31% of patients out of balance at first erect declined to only 12.1% at 2 years.

Selecting the C7-LIV Line Vertebra as the Upper Instrumented Vertebra for Adolescent Idiopathic Scoliosis Lenke Type 1A Curves: Multicenter and a Minimum 2-Year Follow-up Study.

Retrospective multicenter cohort study. We evaluated a new upper instrumented vertebra (UIV) selection method that used the modified Shinshu line (MSL) to establish the selected UIV as the MSL vertebra (MSLV). No reports have addressed optimal UIV selection according to the lower instrumented vertebra (LIV) for good trunk balance in Lenke 1A curves. Forty-five consecutive patients (44 female, 14.4 ± 2.4 yrs) receiving posterior spinal fusion (PSF) for a Lenke 1A adolescent idiopathic scoliosis (AIS) curve were analyzed. We defined the novel MSL as the line between the center of the spinous process of C7 and that of the spinous process of the LIV. The vertebral body with which the MSL first contacted proximally was defined as the MSLV. The groups in which the UIV was at, proximal to, or distal to the MSLV were defined as the matched group (M-group; 15 cases [15 female], 14.7 ± 2.1 yrs), proximal group (P-group; 20 cases, [19 female], 15.0 ± 2.2 yrs), and distal group (D-group; 10 case [10 female], 14.8 ± 2.5 yrs), respectively. We measured Cobb angle, main thoracic (MT) curve correction rate, and C7 plumb line absolute value (C7PL) at pre- and 2 years postoperatively for comparisons using Dunnett test, with the M-group as the control. In the M-group, P-group, and D-group, the Cobb angle correction rate between pre- and postoperative time points were 65.3 ± 1.3%, 62.4 ± 1.6%, and 52.8 ± 6.8%, respectively, and comparable apart from a smaller correction tendency in the D-group versus the M-group (P = 0.08). At 2 years postoperatively, C7PL was 0.5 ± 0.4, 1.0 ± 0.6, and 1.3 ± 0.9 cm, respectively, and significantly smaller for the M-group (both P < 0.05). Better trunk balance were obtained without reducing correction rate by setting the novel MSLV as the UIV in PSF for Lenke type 1A curves. 3.

Risk Factors for Immediate Postoperative Coronal Imbalance in Degenerative Lumbar Scoliosis Patients Fused to Pelvis.

Study Design:Retrospective case-control radiographic study.Objective:To identify risk factors for immediate postoperative coronal imbalance in degenerative lumbar scoliosis (DLS) patients fused to pelvis.Methods:A total of 71 DLS patients treated with deformity correction surgery were reviewed. Measurements included coronal parameters such as global coronal malalignment (GCM), major Cobb angle, L4/L5 coronal tilt and sagittal parameters. Based on the orientation of L4 coronal tilt relative to C7 plumb line (PL) preoperatively, coronal patterns were subdivided into (1) consistency pattern, L4 coronally tilts toward C7 PL, and (2) opposition pattern, L4 coronally tilts opposite C7 PL; the proportion of these 2 patterns was analyzed. Also, the proportion of type C and surgical factors were recorded. According to postoperative GCM, patients were divided into imbalanced group and balanced group.Results:Compared with the balanced group, the imbalanced group had a larger proportion of preoperative consistency pattern (79.17% vs 40.43%, P = .002), larger proportion of type C (29.17% vs 8.51%, P = .023), and lower amount of GCM correction (−4.92 ± 24.25 vs 14.52 ± 19.49 mm, P < .001). There were no significant intergroup differences regarding preoperative and postoperative major Cobb angle, preoperative and postoperative L4 or L5 coronal tilt, major Cobb correction, the amounts of correction of coronal tilt of L4/L5, osteotomy levels, osteotomy grades, instrumented levels, levels of interbody fusion, and distribution of upper instrumented vertebra.Conclusions:In addition to known risk factors such as type C, preoperative coronal consistency pattern might be a new risk factor for postoperative coronal imbalance in DLS patients fused to pelvis.

Introduction of the Novel Radiographic Line (L5-Kyphosis Apex Line) Intended to Evaluate Scheuermann's Disease and Postural Kyphosis Progression on Standard Lateral X-Rays.

Study DesignCross-sectional and follow-up nested study.PurposeTo assess the reliability of the L5-kyphosis apex line (L5-KAL) evaluation and determine the association between changes in L5-KAL, changes in radiological parameters, and changes in clinical symptoms.Overview of LiteratureScheuermann’s disease is the most common cause of hyperkyphosis of the thoracolumbar and thoracic spine during adolescence. Scheuermann’s disease patients usually show compensatory hyperlordosis of the lumbar spine, which is usually flexible, and express an anterior translation of the lumbar section. The L5-KAL was developed on the basis of our clinical experience, displaying the horizontal distance between the thoracic and lumbar curves.MethodsIn the cross-sectional segment, 150 initial lateral X-rays of patients with Scheuermann’s disease and postural kyphosis were analyzed, and 80 additional X-rays were analyzed in the follow-up segment. The data taken from the X-rays of the whole spinal column included the thoracic kyphosis angle, the C7 plumb line, and the L5-KAL. Clinical data included a numerical rating scale of self-perceived body image, pain, and a Scoliosis Research Society-22 questionnaire (SRS-22).ResultsSignificant positive associations were observed in a cross-sectional study between the L5-KAL and thoracic kyphosis, lumbar lordosis, C7 line, and self-perceived body image. In the follow-up nested study, in a mixed analysis of variance, the main effect of time was significant for the L5-KAL, kyphotic deformity and SRS-22, which indicated a change in these parameters after treatment of Scheuermann’s disease patients. Significant positive associations were observed between the changes in L5-KAL and the changes in thoracic kyphosis.ConclusionsOur evidence suggests that the L5-KAL can serve as an indicator of the thoracic curve change in Scheuermann’s disease and postural kyphosis patients and should be considered in clinical practice.

Correlation between Forward Head Posture and Spinal Sagittal Balance

Abstract Background: Forward head posture and other forms of spinal sagittal imbalance at nowadays are a major cause of pain and disability among patients presenting to the spine clinic in daily practice. However, it is unclear if there are correlation between forward head posture and whole spinal balance or no therefore, the purpose of this study was to investigate the correlation between FHP and spinal sagittal balance. Aim of Study: This current study was planned to measure the correlation between FHP and spinal sagittal balance. Material and Methods: This study was carried at El-Sheikh Zayed Specialized Hospital out patient clinic of Physical Therapy. From December 2017 to April 2019. 30 subject aged between 25-35 years old from both sexes with radiological CVA <70' are included in this study, standard full-length lateral radiographs performed in all participant. FHP was assisted by CVA and we assess C7 plumb line for total spinal balance, Co-C2 angle for upper cervical lordosis, C2-C7 (SVA) and C2-C7 angle for lower cervical lordosis, T1 sagittal tilt, T4-T12 angle for thorathic kyphosis, L1-S1 angle for lumber lordosis and Sacral Slope (SS). Correlation analysis was used to identify the direction and strength of the relationship between forward head posture and spinal sagittal balance variables. Results: Forward head posture angle is negatively strong correlated to C2-C7 SVA and has a negative intermediate correlation with T1 tilting and C0-C2 angle but it has aweak positive correlation with C7-S 1 SVA, on the other hand it has an no correlation with C2-C7 angle, sacral slope, lumber lordosis and thoracic kyphosis. Conclusion: Increasing in forward head posture angle leads to increase in C7-S1 SVA and decrease in C2-C7 SVA, T1 tilting and C0-C2 angle. While it has no effect on C2-C7 angle, sacral slope, lumber lordosis and thoracic kyphosis.

Surgical strategy and clinical outcomes in degenerative lumbar scoliosis with type C coronal imbalance

Objective To illustrate the surgical strategy of sequential correction in degenerative lumbar scoliosis (DLS) with type C coronal imbalance, and to evaluate the clinical outcomes and advances of sequential correction technique. Methods Twelve patients (2 males and 10 females) applying sequential correction technique from January 2015 to August 2017 were retrospectively reviewed. The ages of the cohort ranged 48-74 years and the average value was 52.3±8.4 years. The sequential correction technique was mainly applied in 3 steps: correction of local kyphoscoliosis with satellite rod on convex side of lumbar spine; correction of lumbosacral curve with L 4-S1 Intervertebral fusion and satellite rod on convex side of lumbosacral spine; correction of global deformity with bilateral long rods. The coronal parameters including Cobb angle and distance between C7 plumb line and center sacral vertical line (C7PL-CSVL), and the sagittal parameters including global kyphosis (GK) and sagittal vertical axis (SVA) were assessed at pre-operation, post-operationand last follow-up. The quality of life was evaluated using SF-36 questionnaire, and paired t test was used for the statistical analysis. Results The average follow-up period was 16.7±4.8 months. The Cobb angles at pre-operation and post-operation were 59.6°±18.7° and 25.6°±12.4° (t=3.705, P<0.001), respectively. At last follow-up, the average Cobb angle was 27.5°±13.0°, and there was no significant loss of correction (t=0.366, P=0.718). Post-operative C7PL-CSVL changed from 48.5±17.2 mm to 9.7±4.3 mm (t=5.842, P<0.001), of which the average value was 10.1±4.5 mm at last follow-up (t=0.223, P=0.826). At post-operation, 11 patients were with type A coronal imbalance, and 1 patient was still with type C coronal imbalance. The scores of bodily pain, general health, and social functioning were 8.4±1.9, 78.1±9.4 and 76.7±8.4 at pre-operation, 10.2±2.0 (t=2.260, P=0.034) , 89.5±7.6 (t=3.267, P=0.004) and 84.5±9.3 (t=2.156, P=0.042) at post-operation. In addition, there was no implant-related complications during follow-up. Conclusion The sequential correction technique could be well used in adult degenerative lumbar scoliosis patients with type C coronal imbalance, which can simplify the surgical procedure, decrease the rates of post-operative coronal imbalance, and obtain rigid internal fixation. Key words: Adult; Lumbar vertebrae; Intervertebral disc degeneration; Scoliosis; Spinal fusion

Impact of cervical range of motion on the global spinal alignment in ankylosing spondylitis patients with thoracolumbar kyphosis following pedicle subtraction osteotomy

BACKGROUND CONTEXTThe head's center of gravity (COG) plumb line (PL) and C7 PL could be simultaneously positioned over the pelvis in adult spinal deformity with normal cervical mobility. However, the position of the head in relation to the global spinal alignment has yet to be investigated in ankylosing spondylitis (AS) patients with thoracolumbar kyphosis. PURPOSEThe objective of this study was to analyze the position of head in relation to the global spinal alignment in AS-related thoracolumbar kyphosis. STUDY DESIGN/SETTINGRetrospective single-center study. PATIENT SAMPLEAS patients who underwent lumbar pedicle subtraction osteotomy for thoracolumbar kyphosis from January 2010 to August 2016 were reviewed. Only patients with a visible ear canal on the preoperative, immediate postoperative, and final follow-up radiographs were included. OUTCOME MEASURESThe chin-brow angle, cervical range of motion (ROM), lumbar lordosis (LL), thoracolumbar angle, thoracic kyphosis (TK), L1 pelvic angle, pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), TK+LL+PI, PI-LL, maximal kyphosis (MK), deformity angular rate, T1 pelvic angle, T1 tilt, spinosacral angle, sagittal vertical axis (SVA) COG-C7, SVA COG-femoral head (FH), and SVA C7-S were evaluated. Data regarding the health-related quality of life, including the Oswestry disability index (ODI) and visual analogue scale (VAS)-back score, were also collected preoperatively, 2 years postoperatively, and at the latest follow-up. METHODSThe cohort was divided into patients with occiput-trunk (OT) concordance or with OT discordance according to the SVA COG-C7 ≤30 mm or >30 mm, respectively. There was no funding in this study and there are no conflict of interest-associated biases. RESULTSA total of 43 patients (36 males and 7 females) with a mean age of 34.2 years (range, 18–59 years) were identified. There were 17 patients accompanied with OT concordance and 26 patients with OT discordance preoperatively. The cervical ROM was significantly lower (24.0° vs 56.1°, p<.001) and SVA COG-C7 was significantly larger (71.7 mm vs 7.4 mm, p<.001) in patients with OT discordance. Furthermore, the PT was larger (41.0° vs 33.5°, p=.010) in patients with OT discordance. After surgery, the whole cohort showed an improvement in LL (−8.6° vs −52.8°, p<.001). Moreover, the CBVA (25.4° vs 1.3°, p<.001) and SVA COG-C7 (46.2 mm vs 21.6 mm, p<.001) were significantly decreased following lumbar PSO. There were 13 patients accompanied with OT discordance postoperatively, and the cervical ROM was still lower (22.5° vs 42.8°, p=.024) in these patients. Postoperative PT was larger (26.5° vs 20.1°, p=.033) in the patients with OT discordance. At the latest follow-up, there were 17 patients accompanied with OT discordance. In these 17 patients, the cervical ROM was significantly lower (21.0° vs 47.0°, p=.001) and PT was significantly higher (26.2° vs 19.2°, p=.012). The ODI and VAS-back scores demonstrated no significant differences between the two groups preoperatively, 2 years postoperatively, or at the latest follow-up. CONCLUSIONSOT discordance in AS-related thoracolumbar kyphosis could be caused by the reduced cervical ROM. To maintain global spinal balance, the pelvis rotated further backward in response to the larger SVA COG-C7. Moreover, the larger SVA COG-C7 could be decreased after the lumbar PSO. Although there were radiographic differences between the patients with OT concordance and with OT discordance, there was no difference in clinical outcomes, and that a larger sample size and longer follow-up are needed.

Correction of the spine with magnetically controlled growing rods in early onset scoliosis : Apre-to-post analysis of 21patients with 1‑year follow-up.

Several studies have emphasized that the magnetically controlled growing rod (MCGR) technique decreases complications and costs and could be considered asafe procedure for treating patients with early onset scoliosis (EOS). To the best of our knowledge, the sagittal profile of patients with an implanted MCGR has not been sufficiently studied before. The objectives of this study were twofold: firstly, to evaluate the influence of MCGR on the coronal, sagittal and axial planes. Secondly, to analyze changes of cervical alignment post-MCGR implantation. This was aretrospective study of patients with EOS who underwent MCGR from 2012 to 2018. Patients were included if they presented with athoracic or lumbar curvature greater than 40° (Cobb angle) and Risser's sign0. Global analysis of all patients was reported. Patients were stratified preoperatively by thoracic alignment into a hypokyphotic or kyphotic group. Furthermore, the study population was divided into an anteriorly aligned group and a posteriorly aligned group. Sagittal alignment parameters and parameters of coronal and axial plane were measured and the preoperative to postoperative change was compared then analyzed 1 year after surgery. No external funding was procured for this research and the authors' conflicts of interest are not pertinent to the present work. A total of 21 patients were included in the study. There was asignificant coronal correction of the structural and compensatory curves (p < 0.01). Before and after surgery, the coronal C7 plumbline was unchanged and remained within the normal range. Postoperatively, asignificant derotation of the apical vertebra in thoracic and lumbar curves was observed (p < 0.05). Global analysis of the sagittal profile revealed asignificant decrease of TK (p < 0.001) and T9SPi (p = 0.002) with asimultaneous significant increase of T1T3 angle (p = 0.015) and T1T4 angle (p = 0.015). No significant changes of the sagittal parameters of cervical, lumbar and spinopelvic parameters were noted. Among all groups, cervical parameters did not reveal any statistically significant changes. At 1‑year follow up the T1T3 angle (p = 0.01) and T1T4 angle (p = 0.03) were significantly increased. All other measured parameters of sagittal, coronal and axial profile were unchanged. The implantation of MCGR had asignificant impact on the sagittal profile. Notwithstanding, no further compensatory mechanisms of the cervical spine and pelvis had to be recruited to safeguard sagittal alignment.

P142. Management of coronal malalignment in the setting of fractional curve correction

BACKGROUND CONTEXT Sagittal malalignment has been discussed extensively in adult spinal deformity (ASD) literature, while coronal malalignment (CM) and fractional curve (FC) have received less attention. As a result, little guidance currently exists for surgical indications in managing CM, despite it being a relatively common occurrence that can considerably impact patient wellbeing. Patients with CM significantly affected by FC are at particular risk for continued CM postoperatively, along with its complications. PURPOSE Assess types of approach to fusion of the fractional curve in ASD surgery and their relation to coronal alignment and sagittal alignment. STUDY DESIGN/SETTING Retrospective review at single institution. PATIENT SAMPLE A total of 82 ASD patients undergoing primary spinal fusion of 4 or more levels to sacrum or pelvis. OUTCOME MEASURES Baseline (BL), 1-year (Y1) postoperatively and BL-Y1 difference (ΔBL-Y1) in magnitudes of FC, coronal alignment (CA) and sagittal alignment (SA) parameters: pelvic incidence-LL (PI-LL), cervical sagittal vertical axis (cSVA), T1 pelvic angle (TPA). METHODS Patients ≥18 years old undergoing primary ≥4-level fusion to sacrum/pelvis between October 2011 and January 2018 with minimum 6-month follow-up included. Chart review performed for operative dates and details and patient follow-up information. Coronal and sagittal parameters measured using deformity measuring software program. FC measured as segmental angle between L4 and S1. CA measured as distance between C7 plumb line and central sacral vertical line. CA≥20mm designated as CM, per guidelines in literature. Chi-squared test used to compare percentages and ANOVA used to compare means, with significance set at p RESULTS A total of 82 patients studied (68.3%F, age 62.6±13.3, BMI 28.1±6.6, Charlson comorbidity index 0.80±1.16). Nine patients (10.98%) had anterior-posterior fusion (AP), 41 (50%) posterior-only fusion with interbody device (PIB), 32 (39.02%) PSF without interbody (PSF). Twenty-three patients (28.04%) had FC≥15° at BL, 7 (8.54%) at Y1. Forty-one patients (50%) had CM at BL, 35 (42.68%) at Y1. AP fusion patients had least levels fused (6.4 AP, 11.4 PIB, 11.8 PSF, p CONCLUSIONS Fusion to the sacrum/pelvis improves sagittal alignment, fractional curve and coronal alignment in most patients. However, while fractional curve and sagittal alignment are better corrected, coronal malalignment, particularly more severe malalignment at baseline, tends to persist postoperatively. Type of approach and use of interbody device does not appear to significantly impact these results. This should be considered in preoperative planning for patients with coronal deformity. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

P83. Predictive modeling for pseudarthrosis performance benchmarking in 404 patients with a minimum two-year follow up

BACKGROUND CONTEXT In the past, averages from published studies have been used for performance benchmarking. However, in practice and in large studies, usually only a small subset of patients fall within the “average” and therefore the average may not provide a valid benchmark rate. One can overperform or underperform the average and still attain the predicted performance benchmark. Predictive modeling can be used to help set performance standards based on a large number of variables including patients' specific factors, procedure details, use of osteogenic products, site specific variations and many others. This study attempts to use predictive modeling for pseudarthrosis performance benchmarking as a proof of concept in ASD surgery. PURPOSE To use predictive modeling for performance benchmarking in high-volume centers and demonstrate that it is more appropriate than simply using averages. STUDY DESIGN/SETTING Retrospective review of a prospective, multicenter ASD database from 11 different sites PATIENT SAMPLE ASD operative patients with age ≥18, Coronal Cobb ≥ 20deg, SVA ≥5cm, PT≥25deg, and/or thoracic kyphosis (TK) ≥ 60deg with min 2-year follow-up. Exclusion criteria: having a revision for any indication other than pseudo in order to reduce confounding of potential pseudo as a result of the revision surgery. OUTCOME MEASURES HRQOL scores: Oswestry Disability Index (ODI), Short form-36 (SF36), Scoliosis Research Society (SRS22), back/leg pain numerical rating scale (NRS). Radiographic values: max coronal cobb angle, coronal C7 plumb line, pelvic tilt (PT), mismatch between pelvic incidence and lumbar lordosis (PI-LL), thoracic kyphosis (TK), C7 sagittal vertical axis (SVA). Posterior fusion was graded to determine if pseudo has occurred within 2 years postoperative. Demographic, frailty, surgical including BMP and complications data were also collected. METHODS A prior validated and published pseudo predictive model has been constructed from 336 ASD patients with an accuracy of 91.3% and an AUC of 0.94 using 21 out of 82 total variables listed above. This model was deployed with an updated set of patients to determine the predicted pseudo rate for each individual surgical site. Actual pseudo rates of the 11 contributing surgical sites were compared to the predicted values as a means to assess for performance benchmarking. RESULTS A total of 403 patients were included (80.1% Female, avg age 57.9±14.9 years) from a total of 502 operative patients with 99 excluded for having a revision for indication other than pseudo. A total of 129 (32.0%) had pseudo by 2 years. The overall pseudo rates per year were the following: 2008-20.0%, 2009-37.7%, 2010-31.4%, 2011-29.3%, 2012-36.7%, 2013-32.0%, 2014-26.6%, 2015-38.1%. Six sites had actual rates above the overall rate of 32% with 5 sites below. However, the predicted rates varied according to each site and included rates above/below the overall rate. All of the actual rates were larger than the predicted rates except for 4 sites in which the actual and predicted rates were the same. CONCLUSIONS The pseudo rate varied per year and per site. Predictive modeling was able to provide a customized pseudoarthosis rate for each site considering multiple variables allowing for performance benchmarking instead of the average. Even though a site was above the overall average rate, they may be predicted to have a higher rate given the type of patients being treated or procedures done at that site. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

194. Outcomes of surgical treatment for 138 patients with severe sagittal deformity at a minimum two-year follow-up

BACKGROUND CONTEXT The operative treatment of adult spinal deformity (ASD) can be very technically challenging with high complication rates. Despite these challenges it is well established that patients ultimately benefit from such treatment. However the surgical outcomes for patients with severe sagittal deformity have not been reported. PURPOSE To investigate whether patients with severe sagittal deformity have favorable outcomes following surgical correction. STUDY DESIGN/SETTING Retrospective review of a prospective, multicenter adult spinal deformity (ASD) database. PATIENT SAMPLE Inclusion criteria: operative patients with age ≥18, SVA ≥15cm, PI-LL ≥30°, and/or lumbar kyphosis ≥5° with minimum 2-yr follow-up. OUTCOME MEASURES Health-related quality of life (HRQOL) scores included: Oswestry Disability Index (ODI), Short Form-36 (SF36), Scoliosis Research Society (SRS22), back/leg pain numerical rating scale (NRS) and minimum clinically important difference (MCID)/substantial clinical benefit (SCB) for pts eligible to meet them. Radiographic values included: max coronal cobb angle, coronal C7 plumb line, pelvic tilt (PT), mismatch between pelvic incidence and lumbar lordosis (PI-LL), thoracic kyphosis (TK), C7 sagittal vertical axis (SVA). Demographic, frailty, surgical, and complications data were also collected. METHODS Comparisons between 2-yr postop and baseline HRQOL/radiographic data were made. P RESULTS A total of 138 pts were included (54.3% Female, ave age 63.3±11.5yrs). Ave baseline frailty score was 4.1±1.4 indicating the pt to befrail. Ave OR time 386.2±136.5min, EBL 1829.8±1474.6cc. 71 (51.4%) of the pts had a prior fusion; 89.9% posterior fusion only, 9.4% combined anterior-posterior approach. Mean number posterior levels fused 11.5±4.1. 44.9% had a 3-column osteotomy and 68.8% had interbody fusion. All 2-yr postop radiographic parameters were significantly improved compared to baseline (p 0.05). All 2-yr HRQOL measures were significantly improved compared to baseline (p CONCLUSIONS Pts with severe sagittal malalignment benefit from surgical correction at 2-yrs postop both radiographically and clinically despite having a high complication rate. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.