Restoration Of Sagittal Alignment Research Articles

Patient-Specific Surgical Correction of Adolescent Idiopathic Scoliosis: A Systematic Review.

The restoration of sagittal alignment is fundamental to the surgical correction of adolescent idiopathic scoliosis (AIS). Despite established techniques, some patients present with inadequate postoperative thoracic kyphosis (TK), which may increase the risk of proximal junctional kyphosis (PJK) and imbalance. There is a lack of knowledge concerning the effectiveness of patient-specific rods (PSR) with measured sagittal curves in achieving a TK similar to that planned in AIS surgery, the factors influencing this congruence, and the incidence of PJK after PSR use. This is a systematic review of all types of studies reporting on the PSR surgical correction of AIS, including research articles, proceedings, and gray literature between 2013 and December 2023. From the 28,459 titles identified in the literature search, 81 were assessed for full-text reading, and 7 studies were selected. These included six cohort studies and a comparative study versus standard rods, six monocentric and one multicentric, three prospective and four retrospective studies, all with a scientific evidence level of 4 or 3. They reported a combined total of 355 AIS patients treated with PSR. The minimum follow-up was between 4 and 24 months. These studies all reported a good match between predicted and achieved TK, with the main difference ranging from 0 to 5 degrees, p > 0.05, despite the variability in surgical techniques and the rods' properties. There was no proximal junctional kyphosis, whereas the current rate from the literature is between 15 and 46% with standard rods. There are no specific complications related to PSR. The exact role of the type of implants is still unknown. The preliminary results are, therefore, encouraging and support the use of PSR in AIS surgery.

Intraoperative Anteropulsion of an Interbody Fusion Cage During Minimally Invasive Transforaminal Lumbar Interbody Fusion: A Case Report

Expandable cages are very commonly used during minimally invasive lumbar interbody fusion surgery for better restoration of sagittal alignment. We present a rare event of intraoperative expandable cage anteropulsion into the retroperitoneal space. To date, several cases of cage migration have been reported. However, ours is the first case of intraoperative anterior cage migration during minimally invasive lumbar fusion. Herein, we present a case of 70-year-old female planned for minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) for grade II L5–S1 lytic spondylolisthesis. There was an unnoticed anterior longitudinal ligament rupture during the cage expansion manoeuvre. Cage dislodgment was noticed intraoperatively. This was managed by compression of the interbody site posteriorly and insertion of another snugly fitting bullet cage, followed by anterior retroperitoneal exploration in the same setting to retrieve the migrated cage. The patient’s postoperative course was satisfactory. At a 1-year follow-up, patient was ambulatory and asymptomatic. Follow-up imaging showed bony fusion and no signs of implant failure. Expandable TLIF cages can cause iatrogenic release of the anterior longitudinal ligament during expansion. Surgeons must be aware of this rare complication, which can result in anterior cage migration.

Comparison of complications, revisions, spinopelvic parameters, and health-related quality of life after posterior spinal fusion using multiple-rod constructs or two-rod constructs for adult spinal deformity: a systematic review and meta-analysis.

The incidence of mechanical complications is high in patients undergoing posterior spinal fusion (PSF) for adult spinal deformity (ASD), especially for cases with severe sagittal malalignment or a prior spinal fusion requiring three-column osteotomy (3-CO) or spinopelvic fixation (SPF). The purpose of this systematic review and meta-analysis was to compare the complications, revisions, radiographic spinopelvic parameters, health-related quality of life (HRQoL), and surgical data of PSF using multiple-rod constructs to those of two-rod constructs for the treatment of ASD. A comprehensive literature search was performed for relevant studies in PubMed, EMBASE, Web of Science, and the Cochrane Library. Complications, revisions, spinopelvic parameters, HRQoL, and surgical date were compared between patients with ASD who underwent PSF using multiple-rod constructs (multi-rod group) and two-rod constructs (two-rod group). Ten studies, comprising 797 patients with ASD (399 in the multi-rod group and 398 in the two-rod group), were included. All these studies were retrospective cohort studies. There were no significant differences in the surgical, wound-related, and systemic complications between the groups. In the multi-rod group, we noted a significantly lower incidence of rod fracture (RR, 0.43; 95% CI 0.33 to 0.57, P < 0.01), pseudoarthrosis (RR, 0.38; 95% CI 0.28 to 0.53, P < 0.01), and revisions (RR, 0.44; 95% CI 0.33 to 0.58, P < 0.01); a superior restoration of PI-LL (WMD, 3.96; 95% CI 1.03 to 6.88, P < 0.01) and SVA (WMD, 31.53; 95% CI 21.16 to 41.90, P < 0.01); a better improvement of ODI score (WMD, 6.82; 95% CI 2.33 to 11.31, P < 0.01), SRS-22 total score (WMD, 0.44; 95% CI 0.06 to 0.83, P = 0.02), and VAS-BP score (WMD, 1.02; 95% CI 0.31 to 1.73, P < 0.01). Compared with the two-rod constructs, PSF using multiple-rod constructs was associated with a lower incidence of mechanical complications, a lower revision rate, a superior restoration of sagittal alignment, and a better improvement of HRQoL, without increasing surgical invasiveness. Multiple-rod constructs should be routinely considered to for ASD patients, especially for cases with severe sagittal malalignment or a prior spinal fusion requiring 3-CO or SPF.

Single-Position Prone Lateral Lumbar Interbody Fusion Increases Operative Efficiency and Maintains Safety in Revision Lumbar Spinal Fusion.

Multi-centre retrospective cohort study. To evaluate the feasibility and safety of the single-position prone lateral lumbar interbody fusion (LLIF) technique for revision lumbar fusion surgery. Prone LLIF (P-LLIF) is a novel technique allowing for placement of a lateral interbody in the prone position and allowing posterior decompression and revision of posterior instrumentation without patient repositioning. This study examines perioperative outcomes and complications of single position P-LLIF against traditional Lateral LLIF (L-LLIF) technique with patient repositioning. A multi-centre retrospective cohort study involving patients undergoing 1 to 4 level LLIF surgery was performed at 4 institutions in the US and Australia. Patients were included if their surgery was performed via either: P-LLIF with revision posterior fusion; or L-LLIF with repositioning to prone. Demographics, perioperative outcomes, complications, and radiological outcomes were compared using independent samples t-tests and chi-squared analyses as appropriate with significance set at P <0.05. 101 patients undergoing revision LLIF surgery were included, of which 43 had P-LLIF and 58 had L-LLIF. Age, BMI and CCI were similar between groups. The number of posterior levels fused (2.21 P-LLIF vs. 2.66 L-LLIF, P =0.469) and number of LLIF levels (1.35 vs. 1.39, P =0.668) was similar between groups.Operative time was significantly less in the P-LLIF group (151 vs. 206 min, P =0.004). EBL was similar between groups (150mL P-LLIF vs. 182mL L-LLIF, P =0.31) and there was a trend toward reduced length of stay in the P-LLIF group (2.7 vs. 3.3d, P =0.09). No significant difference was demonstrated in complications between groups. Radiographic analysis demonstrated no significant differences in preoperative or postoperative sagittal alignment measurements. P-LLIF significantly improves operative efficiency when compared to L-LLIF for revision lumbar fusion. No increase in complications was demonstrated by P-LLIF or trade-offs in sagittal alignment restoration. Level 4.

The association of rod curvature with postoperative outcomes in patients undergoing posterior lumbar interbody fusion for spinal stenosis: a retrospective case–control study

BackgroundRestoration of sagittal balance is a crucial consideration in posterior lumbar interbody fusion (PLIF) surgery and adverse postoperative outcomes are associated with inadequate restoration of sagittal alignment. However, there remains a shortage of substantial evidence regarding the effect of rod curvature on both sagittal spinopelvic radiographic parameters and clinical outcomes.MethodA retrospective case–control study was conducted in this study. Patient demographics (age, gender, height, weight and BMI), surgical characteristics (number of fused levels, surgical time, blood loss and hospital stay) and radiographic parameters (lumbar lordosis [LL], sacral slope [SS], pelvic incidence [PI], pelvic tilt [PT], PI-LL, Cobb angle of fused segments [Cobb], rod curvature [RC], Posterior tangent angle of fused segments [PTA] and RC-PTA) were analyzed.ResultsPatients in the abnormal group had older mean age and suffered more blood loss than those in the normal group. In addition, RC and RC-PTA were significantly lower in the abnormal group compared to the normal group. Multivariate regression analysis revealed that lower age (OR = 0.94; 95% CI: 0.89–0.99; P = 0.0187), lower PTA (OR = 0.91; 95% CI: 0.85–0.96; P = 0.0015) and higher RC (OR = 1.35; 95% CI: 1.20–1.51; P < 0.0001) were related to higher odds of better surgical outcomes. The receiver operating characteristic curve analysis showed that the ROC curve (AUC) for predicting outcomes of surgery by RC classifier was 0.851 (0.769–0.932).ConclusionsIn patients who underwent PLIF surgery for lumbar spinal stenosis, those who had a satisfactory postoperative outcome tended to be younger, had lower blood loss, and higher values of RC and RC-PTA compared to those who had poor recovery and required revision surgery. Additionally, RC was found to be a reliable predictor of postoperative outcomes.

Revision surgery following long lumbopelvic constructs for adult spinal deformity: prospective experience from two dedicated databases.

Pan Lumbar Arthodesis (PLA) are often required for Adult Spinal Deformity (ASD) correction, reducing significantly the compensatory capacity in case of postoperative sagittal malalignment. Few papers have investigated outcomes and complications in this vulnerable subset of patients. The objective of this study was to assess revision surgery rate for PLA in ASD, its risk factors and impact on clinical outcomes. Retrospective multicenter review of prospective ASD data from 7 hospitals covering Europe and Asia. ASD patients included in two prospective databases having a posterior instrumentation spanning the whole lumbar region with more than 2-years of follow-up were reviewed. Demographic, surgical, radiographic parameters and Health-Related Quality of Life (HRQoL) scores were analyzed. Univariate and multivariate regression models analyzed risk factors for revision surgery as well as surgical outcomes. Patients with Early versus Late and PJK versus Non-PJK mechanical complications were also compared. Out of 1359 ASD patients included in the database 589 (43%) had a PLA and 357 reached 2-years mark. They were analyzed and compared to non-PLA patients. Average age was 67 and 82% were females. 100 Patients (28.1%) needed 114 revision surgeries (75.4% for mechanical failures). Revised patients were more likely to have a nerve system disorder, higher BMI and worst immediate postoperative alignment (as measured by GAP Parameters). These risk factors were also associated with earlier mechanical complications and PJK. Deformity and HRQoL parameters were comparable at baseline. Non-revised patients had significantly better clinical outcomes at 2-years (SRS 22 scores, ODI, Back pain). Multivariate analysis could identify nerve system disorder (OR 4.8; CI 1.8-12.6; p = 0.001), postoperative sagittal alignment (GAP Score) and high BMI (OR 1.07; CI 1.01-1.13; p = 0.004) as independent risk factors for revisions. Revision surgery due to mechanical failures is relatively common after PLA leading to worse clinical outcomes. Prevention strategies should focus on individualized restoration of sagittal alignment and better weight control to decrease stress on these rigid constructs in non-compliant spines. Nerve system disorders independently increase revision risk in PLA. Prognosis.

225. Comparison of single position prone lateral lumbar interbody fusion and lateral lumbar interbody fusion with repositioning in revision lumbar spinal fusion

<h3>BACKGROUND CONTEXT</h3> Prone LLIF (P-LLIF) is a novel technique allowing for placement of a lateral interbody in the prone position and allowing posterior decompression and revision of posterior instrumentation without repositioning. To date, studies evaluating the P-LLIF have been small single surgeon series. This multicentre retrospective cohort examines perioperative outcomes and complications of single position P-LLIF againsttraditional Lateral LLIF (L-LLIF) technique with patient repositioning in patients undergoing revision lumbar fusion surgery. <h3>PURPOSE</h3> To evaluate the feasibility and safety of the single-position P-LLIF technique for revision lumbar fusion surgery. <h3>STUDY DESIGN/SETTING</h3> Multicenter retrospective cohort study. <h3>PATIENT SAMPLE</h3> A total of 101 patients undergoing revision circumferential fusion with lateral lumbar interbody fusion (LLIF) were included, of which 43 had P-LLIF and 58 had L-LLIF. <h3>OUTCOME MEASURES</h3> Outcome measures included levels fused, operative time, estimated blood loss and perioperative complications. Radiographic analysis included lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), PI-LL mismatch and segmental lumbar lordosis. <h3>METHODS</h3> A multicenter retrospective cohort study was performed from 4 institutions from the USA and Australia of patients undergoing revision anterior-posterior lumbar fusion via either: 1) single-position prone LLIF (P-LLIF); or 2) lateral decubitus LLIF with repositioning to prone (L-LLIF) between January 2015 and November 2021. Patients with greater than 4 levels fused were excluded. Demographics, perioperative outcomes, complications and radiological outcomes were compared using independent samples t-tests and chi-squared analyses as appropriate with significance set at p<0.05. <h3>RESULTS</h3> A total of 101 patients undergoing revision lateral lumbar interbody fusion surgery were included, of which 43 had P-LLIF and 58 had L-LLIF. Age, BMI and CCI were similar between groups. The number of posterior levels fused (2.21 P-LLIF vs 2.66 L-LLIF, p=0.469) and interbody levels fused (1.23 P-LLIF vs 1.25 L-LLIF, p=0.838) were similar between groups. Levels decompressed, posterior column osteotomy and anterior column release were similar between groups. Operative time was significantly less in the P-LLIF group compared to the L-LLIF group (151 vs 206 min, p=0.004). EBL was similar between groups (150 mL P-LLIF vs 182 mL L-LLIF, p=0.31) and there was a trend toward reduced length of stay (2.7 vs 3.3 days, p=0.09). No significant difference was demonstrated in perioperative or postoperative complications between P-LLIF and L-LLIF groups. Radiographic analysis demonstrated no significant differences in preoperative or postoperative sagittal alignment as measured by lumbar lordosis, PI-LL mismatch, or segmental lumbar lordosis between groups. <h3>CONCLUSIONS</h3> P-LLIF significantly improves operative efficiency and may reduce length of stay when compared to L-LLIF and repositioning for revision lumbar fusion. No increase in complications was demonstrated by P-LLIF or trade-offs in sagittal alignment restoration. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Usefulness of anterior column release for segmental lordosis restoration in degenerative lumbar kyphosis.

Three-column osteotomies (3COs) for surgical correction of lumbar kyphosis show a strong correction capacity, but this procedure carries high morbidity rates. The anterior column release (ACR) technique was developed as a less invasive procedure. In this study the authors aimed to evaluate sagittal alignment restoration using ACR and to determine factors that affect the degree of correction. This study included 36 patients (68 cases) who underwent ACR of more than one level for adult spinal deformity. Parameters for regional sagittal alignment included segmental lordosis (SL). The parameters for global sagittal alignment included pelvic incidence, lumbar lordosis, sacral slope, pelvic tilt, and sagittal vertical axis (SVA). In addition, the interdiscal height (IDH) and difference of interdiscal angle (DIDA) were measured to evaluate the stiffness of the vertebra segment. The changes in SL were evaluated after ACR and the change of global sagittal alignment was also determined. Factors such as the location of the ACR level, IDH, DIDA, cage height, and additional posterior column osteotomy (PCO) were analyzed for correlation with the degree of SL correction. Thirty-six patients were included in this study. A total of 68 levels were operated with the ACR (8 levels at L2-3, 27 levels at L3-4, and 33 levels at L4-5). ACR was performed for 1 level in 10 patients, 2 levels in 20, and 3 levels in 6 patients (mean 1.9 ± 0.7 levels per patient). Mean follow-up duration was 27.1 ± 4.2 months. The mean SL of the total segment was 0.4° ± 7.2° preoperatively and increased by 15.3° ± 5.5° at the last follow-up (p < 0.001); thus, the mean increase of SL was 14.9° ± 8.1° per one ACR. Global sagittal alignment was also improved following SL restoration with SVA from 101.9 mm to 31.4 mm. The degree of SL correction was correlated with the location of ACR level (p = 0.041) and was not correlated with IDH, DIDA, cage height and additional PCO. This study demonstrated that the mean correction angle of SL was 14.9 per one ACR. The degree of disc space collapse and stiffness of segment did not affect the degree of correction by ACR.

Clinical and Radiographic Comparisons among Minimally Invasive Lumbar Interbody Fusion: A Comparison with Three-Way Matching.

Retrospective cohort study. To compare clinical and radiographic outcomes among minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF), extreme lateral lumbar interbody fusion (XLIF), and oblique lateral lumbar interbody fusion (OLIF) techniques. To date, there are many reports comparing outcomes between MIS-TLIF and XLIF, MIS-TLIF and OLIF, or XLIF and OLIF procedures. However, there are no previous studies comparing clinical and radiographic outcomes among all these three techniques. Data from patients who underwent minimally invasive (MI) fusion surgery for lumbar degenerative diseases at L4-L5 level was analyzed. Thirty patients each from MIS-TLIF, XLIF, and OLIF groups were recruited for propensity score matching. Visual Analog Scale (VAS) of the back and legs and Oswestry Disability Index (ODI) were evaluated preoperatively and at 1, 3, and 6 months and 1 year postoperatively. Radiographic outcomes were also compared. The fusion rate was evaluated at 1 year after surgeries. The clinical outcomes were significantly improved in all groups. The disk height was significantly restored in all groups postoperatively, which was significantly more improved in XLIF and OLIF than MIS-TLIF group (p<0.001). The axial canal area was significantly increased more in MIS-TLIF versus XLIF and OLIF (p<0.001). The correction of lumbar lordotic angle and segmental sagittal angle were similar among these techniques. OLIF and XLIF groups showed less blood loss and shorter hospital stays than MIS-TLIF group (p<0.001). There was no significant difference in fusion rate among all groups. MIS-TLIF, XLIF, and OLIF facilitated safe and effective MI procedures for treating lumbar degenerative diseases. XLIF and OLIF can achieve clinical outcomes equivalent to MIS-TLIF by indirect decompression. XLIF and OLIF showed less blood loss, shorter hospital stays, and better disk and foraminal height restorations. In single-level L4-5, the restoration of sagittal alignment was similar between these three techniques.

How does magnetically controlled growing rods insertion affect sagittal alignment in ambulatory early onset scoliosis patients?

The importance of sagittal alignment restoration in early onset scoliosis (EOS) management has rarely been investigated to date. The aim was to report the influence of magnetically controlled growing rods (MCGR) insertion on the sagittal alignment of EOS patients. All consecutive ambulatory patients operated with MCGR rods between 2011 and 2018 were retrospectively included in four institutions. Standing biplanar radiographs were performed preoperatively, in the early postoperative period and at latest follow-up. Global and local sagittal parameters, spinal global shape and harmony were investigated. A total of 37 ambulatory EOS patients were included (mean age at surgery 8.5 (± 2) years). 70% had a balanced construct postoperatively. Both MaxTK (- 17°, p = 0.02) and MaxLL (- 15°, p = 0.001) were significantly reduced, particularly at the instrumented levels. The number of vertebrae included in the lumbar lordosis significantly increased (+ 2 levels, p = 0.02), as well as the thoraco-lumbar inflexion point (+ 2 levels, p < 0.001) and the kyphosis apex (+ 1 level, p < 0.001). Overall mechanical failure rate was 40.5%, and radiological PJK was observed in 43% of the patients, with 11 remaining asymptomatic. Patients with initial hyperkyphosis (> 50°) developed more complications (62% vs. 28%, p = 0.04). MCGR insertion flattened the spine in EOS, at both instrumented and non-instrumented levels. Overall spinal harmony was modified, with a cranial shift of the thoraco-lumbar inflexion point and the thoracic kyphosis apex, associated with a lengthening of the lumbar lordosis. The rate of complication remained high, some explanations being found in the radiological changes reported such as the preoperative location of the TK apex. IV.

Surgical risk factors associated with the development of adjacent segment pathology in the lumbar spine.

Adjacent segment pathology (ASP) is a major cause of disability, and the recognition of the surgical risk factors associated with the development of this condition is essential for its prevention.Different surgical approaches, from decompression without fusion to non-instrumented and instrumented fusion, have distinct contributions to the development of ASP.Although motion-preservation procedures could reduce the prevalence of ASP, these are also associated with a higher percentage of complications.Several risk factors associated with previous surgery, namely the chosen surgical approach and anatomical dissection, the choice of interbody fusion, the increment and length of the fusion, and the restoration of sagittal alignment, may influence the development of ASP. Cite this article: EFORT Open Rev 2021;6:966-972. DOI: 10.1302/2058-5241.6.210050

Lowest Instrumented Vertebra Selection to S1 or Ilium Versus L4 or L5 in Adult Spinal Deformity: Factors for Consideration in 349 Patients With a Mean 46-Month Follow-Up.

Retrospective cohort study. To compare the outcomes of patients with adult spinal deformity (ASD) following spinal fusion with the lowest instrumented vertebra (LIV) at L4/L5 versus S1/ilium. A multicenter ASD database was evaluated. Patients were categorized into 2 groups based on LIV levels-groups L (fusion to L4/L5) and S (fusion to S1/ilium). Both groups were propensity matched by age and preoperative radiographic alignments. Patient demographics, operative details, radiographic parameters, revision rates, and health-related quality of life (HRQOL) scores were compared. Overall, 349 patients had complete data, with a mean follow-up of 46 months. Patients in group S (n = 311) were older and had larger sagittal and coronal plane deformities than those in group L (n = 38). After matching, 28 patients were allocated to each group with similar demographic, radiographic, and clinical parameters. Sagittal alignment restoration at postoperative week 6 was significantly better in group S than in group L, but it was similar in both groups at the 2-year follow-up. Fusion to S1/ilium involved a longer operating time, higher PJK rates, and greater PJK angles than that to L4/L5. There were no significant differences in the complication and revision rates between the groups. Both groups showed significant improvements in HRQOL scores. Fusion to S1/ilium had better sagittal alignment restoration at postoperative week 6 and involved higher PJK rates and greater PJK angles than that to L4/L5. The clinical outcomes and rates of revision surgery and complications were similar between the groups.

Optimized Surgical Strategy for Adult Spinal Deformity: Quantitative Lordosis Correction versus Lordosis Morphology.

Background: In surgical correction of adult spinal deformity (ASD), pelvic incidence (PI)-lumbar lordosis (LL) plays a key role to restore normal sagittal alignment. Recently, it has been found that postoperative lordosis morphology act as an important factor in preventing mechanical complications. However, there have been no studies on the effect of postoperative lordosis morphology on the restoration of sagittal alignment. The primary objective of this study was to evaluate the effect of postoperative lordosis morphology on achievement of optimal sagittal alignment. The secondary objective was to find out which radiographic or morphologic parameter affects sagittal alignment in surgical correction of ASD. Methods: 228 consecutive patients with lumbar degenerative kyphosis who underwent deformity correction and long-segment fixation from T10 to S1 with sacropelvic fixation and follow-up over 2 years were enrolled. Patients were divided according to whether optimal alignment was achieved (balanced group) or not (non-balanced group) at last follow-up. We analyzed the differences of postoperative radiographic parameters and morphologic parameters between two groups. Correlation analysis and stepwise multiple linear regression analysis was performed to predict the effect of PI-LL and morphologic parameters on the sagittal vertical axis (SVA). Results: Of 228 patients, 195 (85.5%) achieved optimal alignment at last follow-up. Two groups significantly differed in postoperative and last follow-up LL (p < 0.001 and p = 0.028, respectively) and postoperative and last follow-up PI-LL (p < 0.001 and p = 0.001, respectively). Morphologic parameters did not significantly differ between the two groups except lower lordosis arc angle (=postoperative sacral slope). In correlation analysis and stepwise multiple linear regression analysis, postoperative PI-LL was the only parameter which had significant association with last follow-up SVA (R2 = 0.134, p < 0.001). Morphologic parameters did not have any association with last follow-up SVA. Conclusions: When planning spine reconstruction surgery, although considering postoperative lordosis morphology is necessary, it is still very important considering proportional lordosis correction based on individual spinopelvic alignment (PI-LL) to achieve optimal sagittal alignment.

Radius of Curvature in Patient-Specific Short Rod Constructs Versus Standard Pre-Bent Rods.

Recent studies support the need for sagittal alignment restoration when performing lumbar degenerative spinal fusions. The development of patient-specific spine rods (PSSRs) may help maintain or improve sagittal alignment in these surgeries. A retrospective review was conducted for patients who underwent posterior spinal surgeries involving 4 or less levels. The preplanned PSSR radii of curvature (ROC) was compared with standard prebent rods with a ROC of 125 mm. All surgeries were performed at a single institution by 3 surgeons from September 2016 through October 2018. Data were then compared using a 2-tailed paired t test. PSSR had either 1 or 2 definitive ROCs. For rods with 2 ROCs, the "cranial" curve was measured between the upper instrumented level and L4 or L5. The "caudal" curve was measured between L4 or L5 and the lower instrumented level. The PSSR with 1 ROC and the caudal portion of the rods with 2 ROCs were significantly smaller than the industry standard ROC. PSSR demonstrate more acute ROC than industry standard rods. In PSRs, the most lordosis occurs between L4-S1 and flattens out at the thoracolumbar junction, mimicking the normal distribution of lumbar lordosis. PSSRs could help achieve or maintain sagittal alignment and prevent the sequela of flat back syndrome.

Clinical and Radiological Assessment of Interbody Fusion and Short-Segment Fixation in Dorso-Lumbar Fractures

Background: Spine fractures account for a large portion of musculoskeletal injuries worldwide. Approximately 75% to 90% of spinal fractures occur in the thoracic and lumbar spine, with most of these occurring at the thoracolumbar junction (T10-L2). Surgical treatment has demonstrated better clinical and radiological results than conservative treatment. Objective: To evaluate the outcome of short-segment fixation with interbody fusion in dorsolumbar fractures clinically and radiologically. Patients and Methods: This study took place at the Neurotrauma Unit of Neurosurgery Department, Zagazig University Hospitals. It included sixteen patients with thoracolumbar fractures treated by short-segment open transpedicular posterior fixation with interbody fusion. Results: Male was the predominant sex (68.7%), mean age was 37.88 years (range: 19-55 years) and the residence in rural areas was 50 % and in urban areas was 50 %. Housewives were the predominant occupation and constitute 31.3%. 81.3% of patients were married. The most prevalent AO spine type of fracture was A3 fracture where it constituted 62.5% of patients, the level of fracture was L2 in 50 % of patients & about 38% had severe pain as reported on VAS score. In our Study there was significant change in ASIA score 12 weeks postoperatively. While 62.5% had E score preoperatively, 87.5% had it 12 weeks postoperatively and 12.5% turned had score C 12 weeks preoperatively versus no one postoperatively had C ASIA score. Conclusion: Surgical treatment of thoracic and lumbar fractures allows for immediate stabilization of the spine, restoration of sagittal alignment, and the possibility of spinal canal decompression.

Effects of Restoration of Sagittal Alignment on Adjacent Segment Degeneration in Instrumented Lumbar Fusions.

Retrospective case-control study. To investigate the effects of postoperative sagittal alignment on radiographic adjacent segment degeneration (ASD) after lumbar fusion surgery. ASD is one of inherent problems with fusion surgery. Many confounding factors are related to the development of ASD. Recently, sagittal alignment has been emphasized for its significance on ASD. Seventy-three patients who underwent four-level lumbar fusion surgery (L2-S1) were divided into two groups according to postoperative sagittal alignment (pelvic incidence-lumbar lordosis [PI-LL] ≥ or <9°): 44 patients (matched group, including 10 patients who underwent pedicle subtraction osteotomy [PSO] at L4) and 29 patients (mismatched group). The general demographics, radiographic parameters, and clinical outcomes were recorded. Preoperative disc degeneration at L1-2 was evaluated by Pfirrmann grade and Kellgren-Lawrence (K-L) grade. Disc degeneration at L1-2 was evaluated by the K-L grade on 2-year postoperative X-rays. The incidence of radiographic ASD (11 [25%] vs. 16 patients [55%], P = 0.02) and Oswestry Disability Index (ODI) scores (36.9 ± 19.9 vs. 49.4 ± 20.7, P = 0.015) at postoperative 2 years were significantly higher in the mismatched group. There were no significant differences in other demographic and radiographic parameters between the two groups. On subgroup analysis between 10 PSO patients and the mismatched group, the mismatched group showed a higher incidence of radiographic ASD (16 [55%] vs. 1 patient [10%], P = 0.041) and worse ODI scores (49.7 ± 20.5 vs. 39.0 ± 20.7, P = 0.040). Preoperative Pfirrmann grade at L1-2 (odds ratio [OR] = 4.191, 95% confidence interval [CI]: 1.754-10.013, P = 0.001) and postoperative PI-LL mismatch (OR = 4.890, 95% CI: 1.550-15.427, P = 0.007) showed significant relationships with the development of radiographic ASD at postoperative 2 years. The restoration of optimal sagittal alignment, even with PSO, may provide a protective effect on the development of radiographic ASD, although the preoperative disc degeneration grade was a risk factor for radiographic ASD. 3.

P5. In vitro comparison of novel adjustable-lordotic expandable and static hyperlordotic lateral interbody spacers on endplate loading and lordosis correction

BACKGROUND CONTEXT For restoration of sagittal alignment, hyperlordotic lateral lumbar interbody fusion (LLIF) spacers are available as expandable or static spacers with many sizes, and possess up to 30° 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 size and their effect on segmental lordosis correction and anterior-posterior endplate loading is poorly understood. PURPOSE The aim of this study is to compare adjustable-lordosis expandable and static LLIF spacers in regards to lordosis correction and endplate force distribution. STUDY DESIGN/SETTING In vitro human cadaveric study. PATIENT SAMPLE A total of 14 cadaveric specimens. OUTCOME MEASURES Lordosis and anterior-posterior endplate forces. METHODS Fourteen L4–L5 cadaveric segments were used. A 55 lb axial load was applied to L4 to simulate intraoperative loads. Segments were instrumented with bilateral pedicle screws and a sequence of expandable spacers with anterior fixation (n=7) or static spacers (n=7) at varied heights and implant lordosis matched between spacers (nine constructs per spacer), including (A three height and lordosis combinations with intact ALL; and B) six height and lordosis combinations following ALL resection. Segmental lordosis and endplate force-maps were collected and compared between the two spacers. 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 of 50% is equivalent anterior-posterior loading. RESULTS No significant differences in lordosis was observed between spacers except at between the 20° expandable spacer (17.4mm) and the 13mm 20° static spacer (22.5°±4.9° and 16.7°±2.3°, respectively, p=0.020). Equivalent anterior-posterior loading ratios were also quantified. Prior to ALL resection, the 9mm 10° static spacer had a significantly larger ELR than the 20° expandable spacer (11.5mm, p=0.016), indicating more anterior loading with the static spacer (91.5% ± 7.6 versus 70.5% ± 18.8%). Following ALL resection, the 11mm 10°, 11mm 20°, and 13mm 20° static spacers (85.1%, 99.2%, and 94.8%, respectively) all had significantly larger ELRs than the 20° expandable at 11.5mm, 14.7mm, and 17.4mm heights (52.0%, 70.0%, and 76.2%), respectively (p CONCLUSIONS This study suggests that expandable and static spacers have comparable lordosis correction; however, greater anterior endplate loading was observed with static spacers. Increased anterior endplate loading may lead to subsidence. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

The Impact of Surgical Correction of Adult Spine Deformity on Radiological Parameters and Its Correlation With Clinical Outcomes

To evaluate the correlations between changes in radiological parameters and clinical outcomes following adult spinal deformity (ASD) surgery. Radiological assessments are necessary for evaluation of deformity magnitude and choosing the appropriate surgical approach. Some studies have demonstrated the correlation between radiological parameters and pain and disability among patients. However, few studies have evaluated changes in both coronal and sagittal radiological parameters following the surgical treatment of ASD and its correlation with clinical outcomes. Radiological parameters include: pelvic tilt (PT), pelvic incidence (PI), sacral slope (SS), lumbar lordosis (LL), and PI minus LL (PI-LL), and Cobb’s angle and three clinical outcome measures include: visual analog scale (VAS), Oswestry Disability Index (ODI), and Short Form-36 health survey (SF-36), were assessed at baseline and 6 and 12 months after surgery. A total of 95 patients were included. Mean VAS scores and ODI significantly improved from 7.09±2.1 and 61.07±13.6 to 2.64±1.6 and 31.8±16.1 respectively, after surgery (both P&lt;0.001). All items of the SF-36 survey, as well as all radiologic measures, improved significantly following surgery (both P&lt;0.001). We found a significant negative correlation between pre-operative SS and VAS scores (r= -0.307, P=0.002). Energy (r= -0.262, P=0.010) and social functioning (r= -0.248, P=0.015) scales of SF-36. PI-LL was positively associated with ODI (r=0.223, P=0.030) before surgery and energy scale (r= -0.262, P=0.010) of SF-36 after surgery. Surgical treatment of patients with ASD improves clinical outcomes, and in line with previous studies, restoration of sagittal alignment has a more important role in the enhancement of patients’ function and quality of life.

Surgical Restoration of Sagittal Alignment of the Spine: Correlation with Improved Patient-Reported Outcomes: A Systematic Review and Meta-Analysis.

The sagittal-plane curvatures of the human spine are the consequence of evolution from quadrupedalism to bipedalism and are needed to maintain the center of mass of the body within the base of support in the bipedal position. Lumbar degenerative disorders can lead to a decrease in lumbar lordosis and thereby affect overall alignment of the spine. However, there is not yet enough direct evidence that surgical restoration of spinal malalignment would lead to a better clinical outcome. Therefore, the aim of this study was to assess the correlation between patient-reported outcomes and actual obtained spinal sagittal alignment in adult patients with lumbar degenerative disorders who underwent surgical treatment. A comprehensive literature search was conducted through databases (PubMed, Cochrane, Web of Science, and Embase). The last search was in November 2018. Risk of bias was assessed with the Newcastle-Ottawa quality assessment scale. A meta-regression analysis was performed. Of 2,024 unique articles in the original search, 34 articles with 973 patients were included. All studies were either retrospective or prospective cohort studies; no randomized controlled trials were available. A total of 54 relations between preoperative-to-postoperative improvement in patient-reported outcome measures (PROMs) and radiographic spinopelvic parameters were found, of which 20 were eligible for meta-regression analysis. Of these, 2 correlations were significant: pelvic tilt (PT) versus Oswestry Disability Index (ODI) (p = 0.009) and PT versus visual analog scale (VAS) pain (p = 0.008). On the basis of the current literature, lower PT was significantly correlated with improved ODI and VAS pain in patients with sagittal malalignment caused by lumbar degenerative disorders that were treated with surgical correction of the sagittal balance. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Uniportal Endoscopic Lumbar Interbody Fusion.

The cause of radiculopathy is the compression of the nerve root which can be secondary to sliding of the vertebra and reduced disc height. In some patients, decompression alone does not resolve this problem. We describe the uniportal endoscopic transforaminal lumbar interbody fusion technique. Full-endocopic foraminotomy and discectomy are followed by cage implementation and percutaneous instrumentation. The goal of this surgical method is decompression of nerve roots, segment stabilization, disc height, and sagittal alignment restoration. Uniportal endoscopic facet sparing transforaminal transkambin lumbar interbody fusion is a good surgical option to treat degenerative disc disease, mechanical instability, and spondylolisthesis. This method shows favourable clinical outcomes in selected patients.