Restoration Of Sagittal Balance Research Articles

Distal Junctional Failure: A Feared Complication of Multilevel Posterior Spinal Fusions.

Objectives: Distal junctional failure (DJF) is less commonly described than proximal junctional failure following posterior spinal fusion, and particularly adult spinal deformity (ASD) surgery. We describe a case series of patients with DJF, taking into account sagittal spinopelvic alignment, and suggest potential risk factors in light of the current literature. Methods: We performed a single-center, retrospective review of posterior spinal fusion patients with DJF who underwent subsequent revision surgery between June 2009 and January 2019. Demographics and surgical details were collected. Radiographical measurements included the following: preoperative and postoperative sagittal and coronal alignment for each index or revision surgery. The upper-instrumented vertebra (UIV), lower instrumented vertebra (LIV), and fusion length were recorded. Results: Nineteen cases (64.7 ± 13.5 years, 12 women, seven men) were included. The mean follow-up was 4.7 ± 2.4 years. The number of instrumented levels was 6.79 ± 2.97. Among the patients, 84.2% (n = 16) presented at least one known DJF risk factor. LIV was frequently L5 (n = 10) or S1 (n = 2). Six patients had an initial circumferential fusion at the distal end. Initial DJFs were vertebral fracture distal to the fusion (n = 5), screw pull-out (n = 9), spinal stenosis (n = 4), instability (n = 4), and one early DJK. The distal mechanical complications after a first revision included screw pull-out (n = 4), screw fracture (n = 3), non-union (n = 2), and an iatrogenic spondylolisthesis. Conclusions: In this case series, insufficient sagittal balance restoration, female gender, osteoporosis, L5 or S1 LIV in long constructs were associated with DJF. Restoring spinal balance and circumferentially fusing the base of constructs represent key steps to maintain correction and prevent revisions.

Impact of preoperative age-adjusted sagittal imbalance on radiographic and clinical outcomes following 1-level minimally invasive transforaminal lumbar interbody fusion for degenerative spondylolisthesis.

Prior studies investigating the use of minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) for treatment of degenerative lumbar conditions and concomitant sagittal deformity have not stratified patients by preoperative pelvic incidence (PI)-lumbar lordosis (LL) mismatch, which is the earliest parameter to deteriorate in mild sagittal deformity. Thus, the aim of the present study was to determine the impact of preoperative PI-LL mismatch on clinical outcomes and sagittal balance restoration among patients undergoing MI-TLIF for degenerative spondylolisthesis (DS). Consecutive adult patients undergoing primary 1-level MI-TLIF between April 2017 and April 2022 for DS with ≥ 6 months radiographic follow-up were included. Patient-reported outcome measures (PROMs) included the Oswestry Disability Index, visual analog scale (VAS), 12-Item Short-Form Health Survey (SF-12), and Patient-Reported Outcomes Measurement Information System at preoperative, early postoperative (< 6 months), and late postoperative (≥ 6 months) time points. The minimal clinically important difference (MCID) for PROMs was also evaluated. Radiographic parameters included PI, LL, pelvic tilt (PT), and sagittal vertical axis (SVA). Patients were categorized into balanced and unbalanced groups based on preoperative PI-LL mismatch according to age-adjusted alignment goals. Changes in radiographic parameters and PROMs were evaluated. Eighty patients were included (L4-5 82.5%, grade I spondylolisthesis 82.5%, unbalanced 58.8%). Mean clinical and radiographic follow-up were 17.0 and 8.3 months, respectively. The average preoperative PI-LL was 18.8° in the unbalanced group and -3.3° in the balanced group. Patients with preoperative PI-LL mismatch had significantly worse preoperative PT (26.2° vs 16.4°, p < 0.001) and SVA (53.2 vs 9.0 mm, p = 0.001) compared with balanced patients. Patients with preoperative PI-LL mismatch also showed significantly worse PI-LL (16.0° vs 0.54°, p < 0.001), PT (25.9° vs 18.7°, p < 0.001), and SVA (49.4 vs 22.8 mm, p = 0.013) at long-term follow-up. No significant radiographic improvement was observed among unbalanced patients. All patients demonstrated significant improvements in all PROMs (p < 0.05) except for SF-12 mental component score. Achievement of MCID for VAS back score was significantly greater among patients with preoperative PI-LL mismatch (85.7% vs 65.5%, p = 0.045). Although 1-level MI-TLIF did not restore sagittal alignment in patients with preoperative PI-LL mismatch, patients presenting with DS can expect significant improvement in PROMs following 1-level MI-TLIF regardless of preoperative alignment or extent of correction. Thus, attaining good clinical outcomes in patients with mild sagittal imbalance may not require addressing imbalance directly.

Efficacy of PVCR for surgical correction of kyphotic deformity with various etiology and restoration of sagittal balance

Efficacy of PVCR for surgical correction of kyphotic deformity with various etiology and restoration of sagittal balance

Kappa: Preliminary Results on a Novel Technique for Pelvic Fixation in Adult Spinal Deformity Correction.

Retrospective cohort study. Pelvic fixation in degenerative spinal deformation is as crucial as demanding. Several pelvic anchoring technics have been described, but loosening rates remain high for most solutions. Here is described the "Kappa" technic, combining ilio-sacral screws to S2A1 screws at 2years of follow-up. Thirteen patients that underwent a spinal deformity correction with "Kappa" fixation to the pelvis and with more than 2years of follow-up were prospectively included in this study. The surgical technic is described, and clinical and radiographic data have been collected for all patients. The population exhibited an important pre-operative sagittal imbalance (mean SVA of 104,4mm, mean PI-LL mismatch of 22,8°) that had improved significatively after surgery (mean SVA of 75,5mm and mean PI-LL mismatch of 4,9°). No loosening of pull-out of the implants was to deplore at 2years of follow-up. The association of ilio-sacral screw, resistant to pull-out because of the traction axis perpendicular to the construct, to S2A1 screws, known to be effective in sagittal balance restoration seems to be an effective and safe option to pelvic fixation for adult spinal deformity correction. IV.

Evaluating the Changes in Sagittal Balance via EOS Imaging before and after Total Hip Arthroplasty

Background and Aim: Sagittal imbalance is often presented as one of the major problems in individuals suffering from orthopedic pain, particularly those affected by destructive hip joint osteoarthritis. In this regard, total hip arthroplasty (THA) as a therapeutic procedure for such patients has resulted in the restoration of sagittal balance. Therefore, the present study aimed to evaluate the changes in sagittal balance using EOS imaging before and after THA and also reflect on its effect on hip joint function, knee pain, and disability percentage due to low back pain (LBP). Methods: Utilizing a prospective cohort study, a total number of 24 patients suffering from extreme unilateral hip osteoarthritis and in need of unilateral THA were selected based on the inclusion and exclusion criteria, and then, sagittal balance parameters, including pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), sacrofemoral angle (SFA), sacrofemoral distance (SFD), lumbar lordosis (LL), and stem angle (SA) were investigated after performing standing radiographs by means of the EOS device. One year after THA, all the above-mentioned parameters were also measured by EOS imaging before and after the surgery and the patients completed some questionnaires, which is the Oswestry Low Back Pain Disability Index (OLBPDI) to evaluate disability percentage resulting in LBP, the Knee Injury and Osteoarthritis Outcome Score (KOOS) instrument to assess knee pain, and the Harris Hip Score (HHS) measure to rate hip joint function, and then the results were analyzed using the SPSS Statistics software (ver. 17). Results: The patients consisted of 13 males (54.2%) and 11 females (45.8%) with the mean age of 52.87±13.05. The mean score of the preoperative PI was also equal to 54.74±10.66 and it was 58.19±11.58 after the surgery (p=0.025). However, the mean values of other parameters at the preoperative stage did not show any significant changes. As well, hip joint function and knee pain resulting from LBP improved in the patients after the surgery (p&lt;0.001). Conclusion: The study findings demonstrated that THA probably influenced sagittal balance through PI. Moreover, the postoperative hip joint function, knee pain, and disability percentage caused by LBP significantly enhanced compared with those before the surgery. Thus, it was concluded that the evaluation of sagittal balance parameters could help patients with orthopedic pain.

Roussouly type 2 could evolve into type 1 shape as sagittal spinal alignment deterioration progresses with age.

Cross-sectional study. To identify whether Roussouly type 2 could evolve into type 1 as the deterioration progresses. The study group comprised subjects with a low pelvic incidence (PI). All subjects underwent a standing whole spinal radiograph and sagittal parameters were measured: T1 pelvic angle (TPA), lumbar lordosis (LL), PI, pelvic tilt (PT), L4-S1 angle, thoracolumbar kyphosis (TLK), thoracic kyphosis (TK), lumbar sagittal apex (LSA), lordosis distribution index (LDI) and number of vertebrae included in the lordosis (NVL). All subjects were distributed into two groups; with primary (de novo) degenerative scoliosis (PDS) and without PDS. Subjects without PDS were divided into young adult, adult, middle-aged and elderly groups. The differences in sagittal parameters of each subgroup were compared. In total, 270 subjects were included with a mean age of 58.6 years (range 20-87 years). There was a stepwise increase in the proportion of type 1 with age, whereas type 2 decreased. The TPA, PT, PI-LL, TK, TLK and LDI increased with age in subjects without PDS. The TPA, LDI, TLK and TK increased with age in subjects who displayed type 1, whereas the PT, LL, L4-S1 and PI-LL were unchanged. The TPA, PT, PI-LL and TLK increased with age in subjects who displayed type 2, whereas LL and L4-S1 were decreased, while the LDI and TK remained unchanged. The LSA of subjects without PDS became lower and the NVL decreased with age, with similar phenomena found in the subjects with type 2. There was no statistical difference among the groups for the LSA or NVL distribution of subjects with type 1. The TPA, PT and PI-LL of subjects with PDS were greater than those in Group IV, while the SS, LL and TK were less. The Roussouly-type, NVL and LSA distribution were identical between these two groups. Roussouly type 1 shape may not be an actual individual specific spine type. Rather, type 2 could evolve into the "type 1" shape as deterioration of the sagittal spinal alignment progresses with age. Primary (de novo) degenerative scoliosis had little effect on whether type 2 became type 1. This should be taken into consideration during the assessment and restoration of sagittal balance.

Comparative characteristics of sagittal balance in normal children and with spondylolisthesis

BACKGROUND: The measurement of sagittal parameters is an important part of preoperative planning and is also used to evaluate the results of surgical treatment. It is known that in spondylolisthesis (especially at high degrees) the sagittal parameters of the spine differ from those in healthy people. The difference in spinal-pelvic parameters in children and adults without orthopedic pathology has also been proven. One of the tasks of surgical treatment of spondylolisthesis is the restoration of sagittal balance or its maximum approximation to normal values. However, today there is no single accepted norm of sagittal parameters for children, therefore, the question of the optimal tactics of surgical treatment of spondylolisthesis in children remains open.&#x0D; AIM: To determine the parameters of the sagittal balance in normal children and in children with spondylolisthesis.&#x0D; MATERIAL AND METHODS: A retrospective analysis of postural radiographs of 68 children was performed. Patients were divided into 2 groups: group I 43 patients from 8 to 17 years old without spinal pathology. Group II 25 patients with spondylolisthesis from 8 to 17 years old. For each patient, the main spinal and pelvic parameters (PT; PI; SS; LL; PI-LL; TK) were measured and statistical analysis of the data was performed.&#x0D; RESULTS: The study proved that the main parameters of the sagittal balance (PI, PT, SS, LL, TK, PI-LL) in children and adults without pathological deformities of the spinal column are statistically significantly different. Also, there are statistically significant differences between the parameters of the sagittal balance in children and adolescents without spinal pathology and with spondylolisthesis (PI, PT, SS, LL, TK, SFD, PI-LL). In patients with high grade spondylolisthesis, the parameters of thoracic kyphosis and lumbar lordosis are significantly reduced, which should be assessed as a compensatory mechanism for maintaining the vertical position of the body. Children with spondylolisthesis are characterized by a significantly higher PI value.&#x0D; CONCLUSION: The sagittal parameters of the spine in children and adults are different, therefore, for correct preoperative planning, it is necessary to establish the norm of sagittal parameters for children. It is also necessary to take into account the high value of PI in children and adolescents with spondylolisthesis, which may be the etiological factor of this disease. The existing formulas for measuring sagittal balance for children with spondylolisthesis should be used with caution, because a high PI can lead to unreliable theoretical values of PT, SS, LL and TK. The cause of sagittal imbalance can be not only high degrees of spondylolisthesis, but also the tight hamstrings.

Intraoperative Complications of Anterior Lumbar Interbody Fusion: A 5-Year Experience of a Group of Spine Surgeons Performing Their Own Approaches.

Spine surgery has evolved at an accelerated pace, allowing the development of more efficient surgical techniques while providing a decreasing rate of morbimortality. One example of these approaches is the anterior lumbar interbody fusion (ALIF). The aim of this study was to evaluate the surgical complication rate when performing ALIF without the help of a vascular "access" surgeon. A retrospective descriptive study was conducted at the Hospital Universitario San Ignacio between 2014 and 2018 and included all patients who underwent ALIF during this time. A nonsystematic review was performed assessing approach-related complications in ALIF and the impact of "access" surgeons in surgical outcomes. A total of 337 patients were included and 508 levels were fused. ALIF was performed as ALIF-360° (27%), ALIF-lateral lumbar interbody fusion (LLIF) (8.9%), and stand-alone ALIF (62%). Most procedures were single-level fusions (51.9%), 45.4% involved 2 levels, and 2.6% were 3-level fusions. The mortality rate was 0%, and only 9 cases of vascular injury were observed and described. Left and common iliac veins were the predominant affected structures. Only a single case required blood transfusion without any other treatment or intensive care unit surveillance. Our study is consistent with literature reports about ALIF complications, finding an incidence of 1.7%. Therefore, ALIF is an excellent alternative for spine procedures, especially for the levels L5-S1 that require sagittal balance restoration. The approaches were performed without a vascular "access" surgeon and presented complication rates similar to those described in the literature.

Circumferential fusion with open versus percutaneous posterior fusion for lumbar isthmic spondylolisthesis

Study designRetrospective cohort study. ObjectiveTo investigate the clinical and radiographic differences between patients who underwent anterior lumber interbody fusion (ALIF) with either open or percutaneous posterior fusion for lumbar isthmic spondylolisthesis. Summary of background dataCircumferential fusion for isthmic spondylolisthesis is commonly performed with superior clinical outcomes, fusion rates, and restoration of sagittal balance when compared to posterior fusion alone. The outcomes comparing traditional open versus percutaneous posterior fusion in this setting have not been fully evaluated. MethodsA retrospective review of patients who underwent ALIF with either traditional open or percutaneous posterior fusion for isthmic spondylolisthesis between 2014 and 2019 was conducted. Patient demographics, surgical characteristics, and radiographic and clinical outcomes were compared between groups. ResultsA total of 79 patients were included in the final analysis, with 49 in the Open group and 30 in the Percutaneous group. No differences were found with regard to demographic factors between groups including sex, body mass index (BMI), diabetic status, and smoking status. The percutaneous group had less estimated blood loss (EBL, 69.2 mL) and shorter length of stay (3.06 days) compared to the open group (446 mL, p = 0.017; 3.98 days, p = 0.003). Both groups demonstrated significant improvement in all clinical outcome measures after surgery (PCS-12, MCS-12, ODI, VAS Back, and VAS Leg scores). The percutaneous group achieved greater ∆VAS Back (Open = 3.55, Perc = 5.17; p = 0.045) and also had a significantly greater improvements in recovery ratio for VAS Back (Open: 0.43, Perc: 0.73; p = 0.037) and ODI (Open: 0.40, Perc = 0.67; p = 0.031). Regression analysis demonstrated percutaneous surgery to be significant predictor of superior improvement in VAS Back scores (β = 1.957, p = 0.027). ConclusionALIF with percutaneous posterior fusion affords greater improvement in back pain and disability when compared to ALIF with open posterior fusion for isthmic spondylolisthesis. Level of evidenceIII.

166. Lumbar total disc replacement as a part of adult scoliosis surgical treatment of 205 patients with minimum of 2 years of follow-up

<h3>BACKGROUND CONTEXT</h3> Surgical scoliosis treatment in adults must face beyond the curve correction, degeneration disc disease, dislocations, spondylolisthesis with sagittal and frontal unbalance and lumbar kyphosis. Two technical components of the surgery have been used to resolve those difficult problems: the fixation through the pelvis, with a complete loss of lumbar mobility and its consequences. The higher rate of pseudarthrosis, despite complex contracts, on one hand, and the necessity of posterior lumbar osteotomies to restore an acceptable lordosis with severe risk of complications on the other hand. <h3>PURPOSE</h3> To explore the capacity to maintain or restore part of mobility and lumbar lordosis, using total disc replacement TDR), by anterior approach (with or without ALIF) in association with the posterior reduction, fixation. <h3>STUDY DESIGN/SETTING</h3> Retrospective clinical study. <h3>PATIENT SAMPLE</h3> A total of 205 patients, 40M, 165F, 18-82 year old (average age 57 yo). Of these, 112 idiopathic scoliosis never operated before, 43 degenerative scoliosis in adults never operated on, and 50 cases already operated on by posterior approach (below prior surgery). A total of 286 TDR Prodisc were implanted (129 - 1 level, 71 - 2 levels, 5 – 3 levels). <h3>OUTCOME MEASURES</h3> The patients' analysis includes the perioperative, preop and postop VAS and ODI (3, 6, 12, 24, late follow-up), mobility of the disc replacement and the evolution of the curve (Cobb, sagittal parameters). <h3>Methods</h3> Between 2000 and 2018, 123 patients with scoliosis and lumbar disc degeneration have received one or more TDR and eventually ALIF, before or after their posterior fixation reduction. The posterior device associated classically hooks, screws, and the rods. The choice of the TDR is one of the key points as with the deformity, there is a need for semi-constrained (fixed center) prosthesis, to neutralize the shear forces and compensate the deficit of anterior and posterior longitudinal ligaments. <h3>Results</h3> ODI preop was 24/50 and declined to 10 in 24 months, VAS lumbar 7.2, radicular 5.7 prep went to 2.6 and 2.1 at 24 months and stabilized at latest follow-up. The mobility measurement at 24 months showed: 151 of 205 patients had a ROM at the TDR level more than 10° in flexion-extension at 24 months. The lordosis capacity of the implants eventually associated to and ALIF with appropriated angulation, allowed the sagittal balance restoration, with T1 axe correction and pelvic tilt reduction. There were no major complications, 4 anterior hematomas (2 drainages, 2 surgical treatments), 2 partial neurological deficits (1 L4, 1 L5). We had no implant TDR complications, no displacements, no explantation required. 2 cases of screw revised, 6 Posterior device removal (2 total, 4 partial), 2 complementary laminectomies, and 2 extension of posterior instrumentation. <h3>Conclusions</h3> The choice of TDR, with a semi – constrained prosthesis and loss restoration of motion and sagittal balance in adult scoliosis. It shows interest in the results, as a clinical and mobility point of view that is maintained in long-term follow up. That allows to avoid the pelvic fixation in majority of cases, escaping for the clinical bad results and complications of the lawn posterior constructions extend it to the pelvis and also illuminates the risks of posterior transpedicular osteotomies. In elderly people, there is a need for osteodensitometry measurement and eventually cementopalsty of the vertebrae that receive the prosthesis. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

L5 Partial Pedicle Subtraction Osteotomy in High Pelvic Incidence Patients: A New Way to Manage Lordosis

Introduction: Numerous corrective osteotomy techniques have been reported in lumbar area. Owing to mechanical difficulties and reputation of higher neurological risk, L5 pedicle subtraction osteotomy (PSO) has been poorly used and described. Until now, there was no reported specific method of PSO in L5 to manage the shape of the lordosis with respect of local anatomy. The objective of this study was to describe a new partial PSO technique in L5 to manage the lower arc of lordosis in high pelvic incidence patients with fixed sagittal imbalance. Materials and Methods: We describe, here, the surgical technique for a partial PSO at L5 level and the associated technique of instrumentation and correction of lordosis. Results: Two different cases were reviewed retrospectively to illustrate this new technique to manage lordosis. The described technique is feasible either in first intention or in a revision surgery. Radiologic results on lordosis and sagittal balance are exposed. Conclusion: A partial resection of the pedicles at L5 is often sufficient to create enough lordosis, maybe more effective than complete L3 and L4 PSO for restoration of sagittal balance and less aggressive than complete L5 PSO.

Open reduction of thoraco-lumbar fractures and sagittal balance correction using Schanz screws

IntroductionThe correction of thoracic and lumbar spine fractures with a short instrumentation using Schanz screws, is an effective method for stabilization and sagittal balance restoration. Materials and methodsBidirectional observational study, included patients undergoing arthrodesis with Schanz screws to manage thoracic and lumbar fractures, the general characteristics, type, and location of the fracture, besides the gain in height of the vertebral body and segmental angle were analyzed before and after surgery. Clinical and imaging control was performed postoperatively and 1 month after this. p-value<.05 was statistically significant. ResultsOf 35 patients undergoing arthrodesis, 13 were excluded due to the absence of images and follow-up. There was a higher proportion of men, the main location of the fracture and AO spine classification was in T12 and type A4/B1 respectively, there was no intraoperative complication, no transfusion was required, and a short hospital stay. A mild complication was presented in the follow-up. The average pre and postoperative change was 12 degrees in the Cobb angle and 5.2mm vertebral body height in the fractured vertebra, these changes were statistically significant. ConclusionThoracolumbar and lumbar spine fracture correction with short segment fixation using Schanz screws, is an effective, safe and fast, showing significantly vertebral height gain and segmental angle correction, as a consequence, a correction of the balance and alignment of the spine.

The Pelvic Incidence Stratified Sagittal Spinopelvic Alignment in Asymptomatic Chinese Population With Different Age Groups.

Study Design:Cross-sectional study.Objective:To provide the age- and pelvic incidence-related variations of sagittal alignment in asymptomatic Chinese population.Methods:This study recruited asymptomatic adult subjects. All subjects undertook the standing whole spinal radiograph and the sagittal parameters were measured: sagittal vertical axis (SVA), T1 pelvic angle (TPA), lumbar lordosis (LL), thoracic kyphosis (TK), pelvic incidence (PI) and pelvic tilt (PT). All subjects were divided into young, middle aged and elderly groups, then each age group was further divided into 5 subgroups (very low, low, average, high and very high) based on PI values. The relations between PI, age and other parameters were evaluated. The differences in sagittal parameters of each PI subgroup were compared.Results:546 subjects were included with an average age of 38.6 years (18 to 81). The number of subjects over 70 years and with very low PI was relatively small. The average of PI, TPA, PT and LL were 45.9° ± 8.4°, 6.4° ± 6.2°, 11.9° ± 6.6° and 49.2° ± 10.1°, respectively. SVA, TPA, TK and PT increased with age (P < 0.05), while SVA, TPA, PT, PI-LL also increased with PI (P < 0.05). LL, PT, TPA, PI-LL and LL-TK were different among the 5 PI subgroups (P < 0.05). However, the values of LL in elderly subjects with high and very high PI were similar.Conclusion:The age- and PI-related variations in sagittal alignment of Chinese population were provided. The sagittal parameters were significantly influenced by age and PI. The individual pelvic morphology should be carefully considered during the assessment and restoration of sagittal balance.

Reducción abierta de fracturas toracolumbares y corrección del balance sagital usando tornillos Schanz

IntroductionThe correction of thoracic and lumbar spine fractures with a short instrumentation using Schanz screws, is an effective method for stabilization and sagittal balance restoration. Materials and methodsBidirectional observational study, included patients undergoing arthrodesis with Schanz screws to manage thoracic and lumbar fractures, the general characteristics, type, and location of the fracture, besides the gain in height of the vertebral body and segmental angle were analyzed. before and after surgery. Clinical and imaging control was performed postoperatively and 1 month after this. p-value < .05 was statistically significant. ResultsOf 35 patients undergoing arthrodesis, 13 were excluded due to the absence of images and follow-up. There was a higher proportion of men, the main location of the fracture and AO spine classification was in T12 and type A4/B1 respectively, there was no intraoperative complication, no transfusion was required, and a short hospital stay. A mild complication was presented in the follow-up. The average pre and postoperative change was 12 degrees in the Cobb angle and 5.2 mm vertebral body height in the fractured vertebra, these changes were statistically significant. ConclusionThoracolumbar and lumbar spine fracture correction with short segment fixation using Schanz screws, is an effective, safe and fast, showing significantly vertebral height gain and segmental angle correction, as a consequence, a correction of the balance and alignment of the spine.

P65. Total disc replacement as a part of adult scoliosis surgical treatment of 205 patients with minimum of two years of follow-up

BACKGROUND CONTEXT Surgical scoliosis treatment in adults must face beyond the curve correction, degeneration disc disease, dislocations, spondylolisthesis with sagittal and frontal unbalance and lumbar kyphosis. Two technical components of the surgery have been used to resolve those difficult problems: the fixation through the pelvis, with a complete loss of lumbar mobility and its consequences. The higher rate of pseudarthrosis, despite complex contracts, on one hand, and the necessity of posterior lumbar osteotomies to restore an acceptable lordosis with severe risk of complications on the other hand. PURPOSE To explore the capacity to maintain or restore part of mobility and lumbar lordosis, using total disc replacement TDR), by anterior approach (with or without ALIF) in association with the posterior reduction, fixation. STUDY DESIGN/SETTING Retrospective clinical study. PATIENT SAMPLE A total of 205 patients, 40M, 165F, 18-82 years old (average age 57 yo). Of them, 112 idiopathic scoliosis never operated before, 43 degenerative scoliosis in adults never operated on, and 50 cases already operated on by posterior approach (below prior surgery). Of them, 286 TDR Prodisc implanted (129 - 1 level, 71 - 2 levels, 5 – 3 levels). OUTCOME MEASURES The patients’ analysis includes the perioperative, preop and postop VAS and ODI (3, 6, 12, 24, late follow-up), mobility of the disc replacement and the evolution of the curve (Cobb, sagittal parameters), radiographic analysis. METHODS Between 2000 and 2018, 123 patients with scoliosis and lumbar disc degeneration have received one or more TDR and eventually ALIF, before or after their posterior fixation reduction. The posterior device associated classically hooks, screws and the rods. The choice of the TDR is one of the key points as with the deformity, there is a need for semi-constrained (fixed center) prosthesis, to neutralize the shear forces and compensate the deficit of anterior and posterior longitudinal ligaments. RESULTS ODI preop was 24/50 and declined to 10 in 24 months, VAS lumbar 7.2, radicular 5.7 prep went to 2.6 and 2.1 at 24 months and stabilized at latest follow-up. The mobility measurement at 24 months showed: 151 of 205 patients had a ROM at the TDR level more than 10° in flexion-extension at 24 months. The lordosis capacity of the implants eventually associated to and ALIF with appropriated angulation, allowed the sagittal balance restoration, with T1 axe correction and pelvic tilt reduction. There were no major complications, 4 anterior hematomas (2 drainages, 2 surgical treatments), 2 partial neurological deficits (1 L4, 1 L5). We had no implant TDR complications, no displacements, no explanation required. Two cases of screw revised, 6 posterior device removal (2 total, 4 partial), 2 complementary laminectomies, and 2 extension of posterior instrumentation. CONCLUSIONS The choice of TDR, with a semi–constrained prosthesis and loss restoration of motion and sagittal balance in adult scoliosis. It shows interest in the results, as a clinical and mobility point of view that is maintained in long term follow-up. That allows to avoid the pelvic fixation in majority of cases, escaping for the clinical bad results and complications of the lawn posterior constructions extend it to the pelvis and also illuminates the risks of posterior transpedicular osteotomies. In elderly people, there is a need for osteodensitometry measurement and eventually cementopalsty of the vertebra that receive the prosthesis. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

P101. Distal junctional failure: a feared complication of adult spinal deformity surgery

BACKGROUND CONTEXT Distal junctional failure DJF is a rarer and less extensively described complication than proximal junctional failure or kyphosis following adult spinal deformity (ASD) surgery. Multifactorial etiologies are reported for DJF and there is no consensus on which risk factors may contribute to it. PURPOSE The aim of this study was to describe a cohort of patients requiring revision surgery for DJF taking into account sagittal spinopelvic alignment and suggest potential risk factors in light of the current literature. STUDY DESIGN/SETTING Single-center retrospective cohort study. PATIENT SAMPLE Nineteen adult spinal deformity patients with distal junctional failure that required revision surgery. OUTCOME MEASURES Quantification of sagittal alignment correction after revision surgery and number of reoperations. METHODS We performed a single center retrospective review of adult spinal deformity patients who had any type of clinically and radiographically significant distal junctional failure and had to undergo revision surgery between June 2009 and January 2019. Demographic characteristics (age, gender, body mass index and comorbidities), and surgical details were collected to identify risk factors for DJF. Radiographical measurements included a preoperative and postoperative sagittal alignment analysis for each index or revision surgery, distal junctional sagittal Cobb angle and a coronal alignment analysis. The number of fused levels, location of upper instrumented vertebra (UIV), lower instrumented vertebra (LIV) and fusion length were recorded. A case-by-case analysis was performed to identify potential risk factors and main reasons for DJF in light of the current literature. RESULTS Nineteen revision cases due to distal junctional failure are reported. Mean age was 64.74 ± 13.55 years old and average follow-up was 4.7 ± 2.4 years (12 F, 7 M). The average number of instrumented levels was 6.79 ± 2.97. We observed that 84.2 % (n=16) of the patient sample had at least one risk factor for mechanical complications. The most frequently observed LIV was L5 in 10 cases while two patients had a LIV at S1 without pelvic fixation. Only six patients had a circumferential fusion performed in the first surgery. Most frequently observed DJFs were fracture below the fusion (n=2), L5 pull out (n=6), spinal stenosis and instability (n=8). The average time to revision surgery was 15.62 ± 17.86 months, eight cases being revised in the first postoperative year. The most frequent revision was the fusion to the pelvis. In our series, nine patients had to undergo a second revision procedure and three underwent a third revision surgery. After DJF, all patients were sagittally unbalanced. Revision surgery was able to partially restore SVA (60.43±55.24 mm at DJF vs 37.64±34.4 mm postoperatively). CONCLUSIONS Our data supports that female gender, osteoporosis, stopping at L5 or at S1 without iliac fixation in long constructs with UIV proximal to L1 represent a high risk of DJF. Insufficient sagittal balance restoration also probably represents a high risk of DJF and revision surgery. Restoring spinal balance (hardware revision, correction and extension of fusion) and obtaining a solid fusion at the lower extremity of constructs (pelvic fixation, possible anterior column support) represent key steps. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Impact of obesity on restoration of sagittal balance and clinical efficacy after posterior lumbar interbody fusion

To investigate the impact of obesity on the restoration of sagittal balance after posterior lumbar interbody fusion (PLIF). To examine the correlation between obesity and sagittal balance and their influence on clinical efficacy. A total of 183 patients who underwent PLIF for degenerative lumbar diseases between Jan 2015 and Dec 2015 were enrolled in this study. Based on their BMI, patients were divided into three groups: normal weight group (Group A), overweight group (Group B), and obesity group (Group C). Demographic data, intraoperative data, sagittal balance parameters, and clinical function scores were compared between each group. Correlation analysis was conducted between the BMI scores and each sagittal balance parameter. Multiple linear regression was used to assess the impact of each variable on clinical outcomes. All patients finished an average of 22.3 months follow-up. Group C had significantly higher blood loss and longer operations than Group A. SL and PT improved significantly in Group A while did not change in Group C. Compared with Group C, Group postoperative pelvic tilt (PT) was better restored in Group A. BMI was significantly correlated with change of lumbar lordosis (LL) and PT. Multiple linear regression analysis indicated that BMI and change of PT had a great influence on ODI improvement. Obesity may hinder the correction of sagittal balance and improvement of clinical efficacy in patients who undergo PLIF. Restoration of PT should be paid more attention to during surgery, as it may be associated with satisfactory clinical outcomes especially for obesity.

289. Optimizing lateral sagittal correction and anterior-posterior interbody loading: in vitro biomechanical assessment of effect of implant lordosis and height on endplate loading and segmental lordosis

BACKGROUND CONTEXT Restoration of sagittal balance is critical for deformity correction. Hyperlordotic lateral lumbar interbody fusion (LLIF) spacers are available in many sizes, and possess up to 25° of implant lordosis to maximize lumbar lordosis when used in combination with anterior longitudinal ligament (ALL) resection. However, angular mismatch between the implant and vertebral endplates may play a role in subsidence due to asymmetric loading of the anterior implant edge. The relationship between implant height and lordosis selection, and their effect on segmental lordosis correction and anterior-posterior endplate loading, is poorly understood. PURPOSE Investigators quantified segmental lordosis and anterior-posterior endplate loading achieved over a range of commercially available implant dimensions (heights: 9–21mm, and lordosis: 0–25°). STUDY DESIGN/SETTING In vitro human cadaveric study PATIENT SAMPLE Six cadaveric specimens OUTCOME MEASURES Lordosis and anterior-posterior endplate forces METHODS Six L2–L3 cadaveric segments were used. A 112.5 lb axial load was applied to L2 to simulate forces during upright stance. Segments were instrumented with bilateral pedicle screws and a sequence of LLIFs under fluoroscopy, including: (A) 9mm height with 0°, 6° and 10° lordosis with intact ALL; (B) 9mm height with 0°, 6° and 10° lordosis following ALL resection; (C) 11mm height with 10° and 20° lordosis; (D) 13mm height with 20° lordosis; and (E) 25° lordosis of 13, 15, 17, 19 and 21mm heights. Segmental lordosis and endplate force-maps were collected until anterior expulsion precluded testing completion (n=6, unless otherwise noted). An equivalent loading ratio (ELR=anterior load/total load*100%) was calculated; ELR=80% refers to 80% anterior and 20% posterior edge loading. An ELR between 40–60% is believed to be desirable. RESULTS The average intact L2–L3 lordosis was 8.5°±2.6° (n=6). With the ALL intact, the 9mm 10° spacer increased lordosis to 10.6°±2.9° (P>0.05). Following ALL resection, use of 11mm 10° and 20° spacers increased lordosis to 14.6°±2.2° and 15.3°±1.8° (P>0.05), respectively. The 13mm 20° and 25° LLIF significantly increased lordosis to 16.7°±2.3° and 16.4°±2.3°, respectively, compared to intact and all constructs prior to ALL release (P CONCLUSIONS This study suggests that LLIF implant lordosis and height can be optimized to mitigate excessive anterior loading while maximizing lordosis correction. Following ALL release, larger spacers with greater posterior heights—not necessarily implant lordosis—may have an increased effect on segmental lordosis while reducing anterior edge loading. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Transpedicular Screw Fixation for Degenerative Lumbar Spine Stenosis with Segmental Instability

Objectives: Evaluation of the Transpedicular Screw Fixation as a surgical treatment for the degenerative lumber spin stenosis with segmental instability. Methods: A prospective, uncontrolled and interventional study conducted on thirty patients with low back pain and associated sciatica and claudication due to degenerative spinal stenosis and instability between March 2017-August 2018. Pain assessment, dynamic x rays and MRI was done perioperatively. Results: By comparison of pre- and post-operative translational motion, it has been found that more cases tend to be “fixed in plane” with high statistically significant testing (p=0.00677) by using Wilcoxon signed rank. In the same line, angular motion was compared perioperatively with the same test above, it has been found that vertebral line is more fixed as regard angular motion with high statistically significant result (p=0.0074). By comparing both variables to test the existence of good operative results with presence of “changed” vertebral alignment from instable to stable. It has been found that good results were statistically significant associated with changed alignment from moving to unmovable spinal segment (p < 0.0001). Conclusion: Posterolateral pedicle screws insertion for degenerative lumbar spine is a good option for restoration of sagittal balance, decompression of canal stenosis and needs no demanding experience or learning curve to serve patients with lumbar spine stenosis and instability.

Comparison of Circular and Sagittal Reinforced Rod Options on Sagittal Balance Restoration in Adolescents Undergoing Pedicle Screw Instrumentation for Idiopathic Scoliosis

Pedicle screw instrumentation is widely used for spinal deformity correction and fusion in adolescents for idiopathic scoliosis. The goal is to achieve and sustain good alignment in all 3 planes. We compared 2 different cobalt-chromium (CoCr) rod designs with different stiffnesses with regard to the restoration of coronal and sagittal balance in adolescents operated on for idiopathic scoliosis. A prospective comparative study was made of 90 consecutive adolescents, mean age (standard deviation) 15.6 years (2.1 years), with idiopathic scoliosis who underwent posterior spinal fusion by the use of bilateral segmental pedicle screw instrumentation (PSI) with 6.0 Co-Cr rods. Fifty-four adolescents (43 girls) were operated on by the use of circular rods and 36 (27 girls) by the use of sagittal reinforced rods, with a 2-year follow-up. Preoperative major coronal curves were similar and at 2 years: 11° (5.0) and 17° (7.2) with correction percentages of 78% (10) and 69% (12) in the circular and reinforced rod groups (P < 0.01). Thoracic kyphosis at 2 years measured 16° (7) and 21° (6) in the circular and reinforced rod groups (P < 0.01). The number of patients with hypokyphosis was lower in the reinforced rod group at 2 years (P= 0.02). In the reinforced rod group, there was a negative correlation between coronal correction and thoracic kyphosis (r=-0.52, P < 0.01). Both circular and sagittal reinforced 6.0-mm CoCr rods provide adequate coronal correction for adolescents with idiopathic scoliosis. The use of sagittal reinforced rods provided better thoracic kyphosis restoration and a lower risk for postoperative hypokyphosis.