Segmental Lordosis Research Articles

Increased cage angle effects on radiographic outcomes after stand-alone anterior lumbar interbody fusion.

Anterior lumbar interbody fusion (ALIF) is a well-accepted surgical technique used to treat various lumbar degenerative pathologies. Recently, hyperlordotic cages have been introduced to create higher degrees of lordosis to the lumbar spine. There are little data currently available to define the radiographic benefits that these cages provide with stand-alone ALIF. The goal of the present study was to assess the effect of increasing cage angles on postoperative subsidence, sagittal alignment, and foraminal and disc height in patients who underwent single-level stand-alone ALIF surgery. A retrospective cohort study was performed of consecutive patients who underwent single-level ALIF by a single spine surgeon. Radiographic analysis included global lordosis, operative level of segmental lordosis, cage subsidence, sacral slope, pelvic tilt, pelvic incidence, pelvic incidence-lumbar lordosis mismatch, edge loading, foraminal height, posterior disc height, anterior disc height, and adjacent-level lordosis. Multivariate linear and logistic regressions were performed to analyze the relationship between cage angle and radiographic outcomes. Seventy-two patients were included in the study and divided into three groups based on cage angle: < 10° (n = 17), 10°-15° (n = 36), and > 15° (n = 19). Within the entire study cohort, there were significant improvements in disc and foraminal height, as well as segmental and global lordosis, at the final follow-up after single-level ALIF. However, when stratified by cage angle groups, patients with > 15° cages did not have any additional significant changes in global or segmental lordosis compared with those patients with smaller cage angles, but patients with > 15° cages showed greater risk of subsidence while also having significantly less improvements in foraminal height, posterior disc height, and average disc height compared with the other groups. Patients with < 15° stand-alone ALIF cages showed improved average foraminal and disc (posterior, anterior, and average) height without sacrificing improvements in sagittal parameters or increasing risk of subsidence when compared to patients with hyperlordotic cages. The use of hyperlordotic cages > 15° did not provide spinal lordosis commensurate with the lordotic angle of the cage and had a greater risk of subsidence. Although this study was limited by a lack of patient-reported outcomes to correlate with radiographic results, these findings support the judicious use of hyperlordotic cages in stand-alone ALIF.

Stand-Alone Oblique Lumbar Interbody Fusion (OLIF) for the Treatment of Adjacent Segment Disease (ASD) after Previous Posterior Lumbar Fusion: Clinical and Radiological Outcomes and Comparison with Posterior Revision Surgery.

Background: Radiological evidence of adjacent segment disease (ASD) has been reported to have a prevalence of more than 30% and several risk factors have been reported. The aim of this study is to evaluate the clinical and radiological outcomes of patients with symptomatic ASD treated with stand-alone OLIF and compare results with a posterior revision surgery cohort. Methods: This is a retrospective case-control study. Clinical-patient-reported outcomes were obtained at preoperative, postoperative and final follow-up visits using the Short Form (SF-36) scale, the Oswestry Disability Index (ODI) and the visual analog scale (VAS). Radiological measures include lumbar lordosis (LL), segmental lordosis (SL), pelvic incidence-lumbar lordosis (PI-LL) mismatch, segmental coronal Cobb angle and intervertebral disc height (DH). The data are compared with a retrospective series of patients that underwent a posterior revision surgery for ASD. Results: Twenty-eight patients in the OLIF group and 25 patients in the posterior group meet inclusion criteria. The mean ages at the time of the surgery are 65.1 years and 67.5, respectively. The mean follow-up time is 36.1 months (range of 14-56). The clinical outcomes significantly improve from preoperative values from the surgery in both groups. The radiological parameters are significantly improved postoperatively and were maintained at the last follow-up in both groups. A statistically significant difference is observed between the two groups for minor complication rate, length of surgery, blood loss and DH restoration. Conclusions: Stand-alone OLIF is an effective and safe technique with low morbidity and complication rates for the treatment of selected patients with symptomatic ASD following a previous lumbar fusion.

Biplanar Expandable Cages for Transforaminal Lumbar Interbody Fusion Are Safe and Achieve Good 1-Year Clinical and Radiological Outcomes in an Asian Population.

This study investigated 1-year clinical and radiological outcomes of biplanar expandable (BE) cages following transforaminal lumbar interbody fusion (TLIF) in an Asian population. A retrospective review was conducted of all consecutive patients who underwent TLIF with BE cages performed by 2 fellowship-trained spine surgeons from 2020 to 2021. Inclusion criteria included open or minimally invasive (MIS) TLIF, of up to 3 spinal segments, performed for treatment of degenerative disc disease, spondylolisthesis, or spinal stenosis. Patient-reported outcomes, including visual analog score (VAS) for back and lower limb pain, Oswestry Disability Index (ODI) and North American Spine Society neurogenic symptom score (NSS), and various radiographic parameters, were evaluated. A total of 23 patients underwent TLIF with BE cages with a follow-up duration of 1.25 years. Of those patients, 7 (30%) underwent 1-level TLIF, 12 (52%) underwent 2-level TLIF, and 4 (18%) underwent 3-level TLIF, with a total of 43 spinal segments fused. Four patients (17%) underwent MIS TLIF while 19 patients (83%) underwent open TLIF. VAS for back pain scores improved by 4.8 ± 3.4 (P < 0.001) from 6.5 ± 2.6 to 1.7 ± 2.2; VAS for lower limb pain scores improved by 5.2 ± 3.8 (P < 0.001) from 5.7 ± 3.4 to 0.5 ± 1.6; ODI scores improved by 29.0 ± 18.1 (P < 0.001) from 49.4 ± 15.1 to 20.4 ± 14.2; and NSS scores improved by 36.8 ± 22.1 (P < 0.001) from 53.3 ± 21.1 to 16.5 ± 19.8. Significant improvements in radiological parameters included increase in anterior disc height, posterior disc height, foraminal height, segmental lordosis, and lumbar lordosis. There were no implant-related complications, cage subsidence, cage migration, or revision surgery at 1 year. TLIF performed with BE cages led to significantly improved patient-reported outcomes and radiographic parameters at 1 year and is safe for use in Asians. The results of this study support the effectiveness and safety of TLIF with biplanar expandable cages.

Endoscopic anterior to psoas lumbarinterbody fusion: indications, techniques, and clinical outcomes.

The retrospective study aimed to report the surgical technique and clinic-radiological outcomes of endoscopic anterior to psoas interbody lumbar fusionthrough the retroperitoneal approach with direct and indirect decompression. We retrospectively analyzed the results of clinical parameters of patients who underwent endoscopic anterior to psoas interbody lumbar fusion between June 2013 and June 2022. Clinical outcomes were evaluated by the visual analog scale (VAS) and Oswestry Disability Index (ODI) scores. The radiological outcomes were measured and statistically compared in disc height index (DHI), whole lumbar lordosis (WLL), pelvic Incidence (PI), pelvic tilt (PT), Segmental lordosis (SL), the sagittal vertical axis (SVA). A total of 35 patients were selected for the procedure ranging in age from 51 to 84years with 17.83 ± 8.85months follow-up. The mean operation time in lateral position for one level was 162.96 ± 35.76min (n = 24), and 207.73 ± 66.60min for two-level fusion. The mean endoscopic time was 32.83 ± 17.71min per level, with a total estimated blood loss of 230.57 ± 187.22cc. The mean postoperative VAS back, leg pain score and ODI improved significantly compared to the preoperative values; Radiological data showed significant change in WLL, SL, DHI, PI, PT, and SS; however, there is no significant difference in SVA postoperatively. Subgroup analysis for the radiographic data showed 50mm length cage has significantly improved for the DHI, SS and SVA compare to 40mm length cage. The subgroup analysis results showed that hypertensive patients had significantly higher proportion in the incomplete fusion group compare to complete fusion group at one-year follow-up. The endoscopic anterior to psoas interbody lumbar fusion achieves satisfactoryindirect and direct decompression. This convergent techniquepresents an effective choice for treating lumbar instability associated withdischerniations and foraminal stenosis, thus complementing the indications for oblique lumbar interbody fusion.

493 One and Two-Level Robotic MIS TLIF With Expandable Implants Demonstrates a Favorable Safety Profile and Improved Alignment Parameters

INTRODUCTION: Minimally invasive surgery (MIS) transforaminal lumbar interbody fusion (TLIF) is an established technique, but continues to evolve with the development of expandable titanium cages and robotic screw insertion. METHODS: This retrospective case series assessed clinical data, complications, and radiographic outcomes at short term follow-up. Screw placement was performed using intraoperative 3D imaging and robotic navigation, and TLIFs were performed via complete facetectomy from a unilateral trajectory in line with pedicle screws using titanium expandable cages. RESULTS: 22 patients, 32 levels, and 108 inserted screws were analyzed. Implants included curved cages in 14 levels, 2 straight cages (diverging “V” pattern) in 12 levels, and a single straight cage in 6 levels. 21/22 patients (95%) had decreased pain. 4/22 patients (18%) experienced complications including deep infection causing screw pullout (requiring revision), painful radiculopathy, contact dermatitis (glue), and UTI. 108/108 screws (100%) showed excellent position. Increases were observed in average segmental lordosis (4.3 ± 4.9°), anterior disc height (6.6 ± 3.5 mm), posterior disc height (4.1 ± 2.1 mm), and foraminal height (5.0 ± 3.1 mm). Improved alignment was observed in 3/3 patients (100%) with SVA &gt; 50 mm (78.3 ± 13.3 mm to 41.7 ±14.3 mm), 3/4 (75%) with pelvic tilt &gt;=25° (30.3 ± 1.5° to 22.7 ± 4.0°), 5/5 (100%) with lumbopelvic mismatch &gt; 10° (PI – LL: 21.4 ± 2.1° to 9.8 ± 8.5°), 13/13 (100%) with anterolisthesis (6.5 ± 2.3 mm to 1.8 ± 1.9 mm), and 4/4 (100%) with segmental coronal imbalance &gt;5° (8.0 ± 3.2° to 2.8 ± 1.3°). CONCLUSIONS: Robotic MIS TLIF with expandable cages has a favorable safety profile, successful short-term clinical results, and is effective at correcting mild spinal malalignment.

Reduction of spondylolisthesis and restoration of lumbar lordosis after anterior lumbar interbody fusion (ALIF)

BackgroundAnterior lumbar interbody fusion (ALIF) is a well-established surgical treatment option for various diseases of the lumbar spine, including spondylolisthesis. This study aimed to evaluate the postoperative correction of spondylolisthesis and restoration of lumbar and segmental lordosis after ALIF.MethodsPatients with spondylolisthesis who underwent ALIF between 2013 and 2019 were retrospectively assessed. We assessed the following parameters pre-and postoperatively (6-months follow-up): Visual Analogue Scale (VAS) for pain, Oswestry Disability Index (ODI), lumbar lordosis (LL), segmental lordosis (SL), L4/S1 lordosis, and degree of spondylolisthesis.Results96 patients were included. In 84 cases (87.50%), additional dorsal instrumentation was performed. The most frequent diagnosis was isthmic spondylolisthesis (73.96%). VAS was reduced postoperatively, from 70 to 40, as was ODI (50% to 32%). LL increased from 59.15° to 64.45°, as did SL (18.95° to 28.55°) and L4/S1 lordosis (37.90° to 44.00°). Preoperative spondylolisthesis was 8.90 mm and was reduced to 6.05 mm postoperatively. Relative spondylolisthesis was 21.63% preoperatively and 13.71% postoperatively. All clinical and radiological improvements were significant (all p < 0.001). No significant difference considering the lordosis values nor spondylolisthesis was found between patients who underwent ALIF surgery without dorsal instrumentation and patients who received additional dorsal instrumentation. Venous laceration was the most frequent complication (10.42%).ConclusionsWith ALIF, good clinical results and safe and effective reduction of spondylolisthesis and restoration of lordosis can be achieved. Additional dorsal instrumentation does not significantly affect postoperative lordosis or spondylolisthesis. Individual vascular anatomy must be reviewed preoperatively before considering ALIF.

Comparison of segmental lordosis gain of prone transpsoas (PTP) vs. lateral lumbar interbody fusion.

Lumbar interbody fusion is a standard method to treat certain degenerative conditions that are refractory to conservative treatments. LLIF reduces posterior muscle damage, can relieve neurological symptoms through indirect decompression, provides increased stability with its wider cages, and promotes more significant segmental lordosis than standard posterior techniques. However, the technique possesses its issues, such as unusual positioning, possible plexus-related symptoms, and median segmental lordosis correction. Trying to ease those issues, the idea of a prone transpsoas technique occurred. Retrospective, single-centric, comparative, and non-randomized study. The authors paired patients receiving lateral lumbar interbody fusion (LLIF) or prone transpsoas (PTP) to evaluate the technique's impact on the segmental lordosis correction. A correlation test selected the covariates for the matching. p-Values inferior to 0.05 were deemed significant. Seventy-one patients were included in the analysis, 53 in the LLIF group and 18 in the PTP group. The significant covariates to the segmental lordosis correction were technique, preoperative segmental lordosis, cage position, and preoperative pelvic tilt. After the paring model, PTP showed significant segmental lordosis correction potential regarding the LLIF. The prone transpsoas approach can significantly enhance the correction of segmental lordosis proportionated to the traditional LLIF approach.

Lateral versus posterior approaches to treat degenerative lumbar pathologies-systematic review and meta-analysis of recent literature.

The lateral lumbar interbody fusion arose as a revolutionary approach to treating several spinal pathologies because the techniques were able to promote indirect decompression and lordosis restoration through a minimally invasive approach allowing for reduced blood loss and early recovery for patients. However, it is still not clear how the technique compares to other established approaches for treating spinal degenerative diseases, such as TLIF, PLIF, and PLF. This is a systematic review and meta-analysis of articles published in the last 10years comparing lateral approaches to posterior techniques. The authors included articles that compared the LLIF technique to one or more posterior approaches, treating only degenerative pathologies, and containing at least one of the key outcomes of the study. Exclusion articles that were not original and the ones that the authors could not obtain the full text; also articles without the possibility to calculate the standard deviation or mean were excluded. For count variables, the odds ratio was used, and for continuous variables, the standard means difference (SMD) was used, and the choice between random or fixed-effects model was made depending on the presence or not of significant (p < 0.05) heterogeneity in the sample. Twenty-four articles were included in the quantitative review. As for the intra-/perioperative variables, the lateral approaches showed a significant reduction in blood loss (SMD-1.56, p < 0.001) and similar operative time (SMD = - 0.33, p = 0.24). Moreover, the use of the lateral approaches showed a tendency to lead to reduced hospitalization days (SMD = - 0.15, p = 0.09), with significantly reduced odds ratios of complications (0.53, p = 0.01). As for the clinical outcomes, both approaches showed similar improvement both at improvement as for the last follow-up value, either in ODI or in VAS-BP. Finally, when analyzing the changes in segmental lordosis and lumbar lordosis, the lateral technique promoted significantly higher correction in both outcomes (p < 0.05). Lateral approaches can promote significant radiological correction and similar clinical improvement while reducing surgical blood loss and postoperative complications.

Imaging analysis and predictive nomogram construction for degenerative lumbar spondylolisthesis with severe clinical symptom based on propensity score matching

Intervertebral disc degeneration, local lumbar segmental morphology changes, and atrophy of multifidus muscle have been considered to be associated with degenerative lumbar spondylolisthesis. However, there remains a great deal of controversy. To further investigate their relationship with degenerative lumbar spondylolisthesis, we conducted a retrospective study that included 67 patients with degenerative spondylolisthesis and 182 control subjects. Propensity score matching was employed to match the case group and the control group. Disc height was evaluated by the anterior disc height index (DHIA) and posterior disc height index (DHIP). Local lumbar segmental morphology was assessed by segmental lordosis (SL). The fatty infiltration and atrophy of multifidus muscle was evaluated by multifidus muscle net content (MFNC). Our results indicate that DHIA, DHIP, SL, and MFNC in the case group were significantly lower than in the control group. Furthermore, the DHIA, DHIP, and MFNC of the slipped segment (L4/5) were lower than those of the non-slipped segment (L3/4). Correlation analysis showed a high relationship between DHIA and MFNC and the degree of degenerative lumbar spondylolisthesis. Logistic regression analysis revealed that DHIA and MFNC might act as protective factors against the development of degenerative lumbar spondylolisthesis. Additionally, a prognostic nomogram was developed and validated to assess the likelihood of patients with severe symptoms requiring surgical intervention.

Variation in Lumbar Shape and Lordosis in a Large Asymptomatic Population: A MEANS Study.

Prospective, cross-sectional cohort study. To determine the relationship between lumbar shape and sagittal parameters. Understanding the lumbar shape is vital for deformity surgery. Normative sagittal parameters and spine shape remain unstudied in large, multiethnic, asymptomatic cohorts. A prospective, cross-sectional cohort of 468 asymptomatic volunteers between 18 and 80 years was enrolled across 5 countries. Demographic data and radiographic parameters such as pelvic incidence (PI) were collected. Pearson correlation test and linear regression were used to find the relationship between lumbar lordosis (LL) and other parameters. One-way analysis of variance and Welch 2-sample t test were performed to compare lumbar shape across such categories as PI and lumbar apex followed by post hoc Bonferroni correction if needed. PI was moderately correlated with proximal lumbar lordosis (pLL) ( r = -0.54) and weakly correlated with distal lumbar lordosis (dLL) ( r = -0.16). Thoracic kyphosis (T1-T12) was moderately correlated with pLL ( r = -0.35) and dLL ( r = -0.29). dLL was moderately correlated with LL ( r = 0.64). 2.6% (12/468) of subjects had lumbar apex at L2, 40.2% (188/468) at L3, 56.6% at L4 (265/468), and 0.6% (3/468) at other levels. Mean PI was different between volunteers with the apex at L3 and L4. A lower mean PI was associated with the apex at L4 (49.0°), whereas a higher mean PI was associated with the apex at L3 (55.8°). The mean PI-LL mismatch for volunteers was -5.4° with a range from -35° to 39.7°. PI-LL mismatch increased from a mean of -10.1° in volunteers with low PI to a mean of 2.2° in volunteers with high PI. Age was not correlated with LL ( P = 0.84). In asymptomatic adult volunteers, pLL showed a moderate correlation with PI and increased with PI, whereas dLL showed a weak correlation. The lumbar apex migrated proximally with increasing PI. Segmental lordosis and apex position instead of solely global lordosis should be emphasized. Level III.

Lateral Lumbar Interbody Fusion Using Expandable vs Static Titanium Interbody Cages: A Prospective Cohort Study of Clinical and Radiographic Outcomes.

Expandable cages are a recent development employed to reduce subsidence and improve fusion compared with static cages as they alleviate the need for repeated trialing or overdistraction of the disc space. This study aimed to compare the radiographic and clinical outcomes in patients undergoing lateral lumbar interbody fusion (LLIF) with either an expandable or static titanium cage. This was a prospective study of 98 consecutive patients undergoing LLIF performed over a 2-year period, with the first 50 patients receiving static cages and the following 48 receiving expandable cages. Radiographic evaluation included interbody fusion status, cage subsidence, and change in segmental lordosis and disc height. Clinical evaluation assessed patient-reported outcome measures (PROMs), including the Oswestry Disability Index, visual analog scale (VAS) for back and leg pain, and short form-12 physical and mental health survey scores collected at 3, 6, and 12 months postoperatively. The 98 patients had 169 cages impacted (84 expandable vs 85 static). Mean age was 69.2 years, and 53.1% were women. There was no significant difference between the 2 groups in terms of age, gender, body mass index, or smoking status. The expandable cage group had higher rates of interbody fusion (94.0% vs 82.9%, P = 0.039) at 12 months as well as significantly reduced implant subsidence rates at all follow-up timepoints (4% vs 18% at 3 months; 4% vs 20% at 6 and 12 months). Patients from the expandable cage group showed a mean 1.9 more points of reduction in VAS back pain (P = 0.006) and 2.49 points greater reduction in VAS leg pain (P = 0.023) at 12-month follow-up. Expandable lateral interbody spacers resulted in significantly improved fusion rates with reduced subsidence risks and statistically significant improvement in PROMs up to 12 months postoperatively compared with impacted lateral static cages. The data provide clinical relevance in favoring expandable cages over static cages for enhanced fusion outcomes in lumbar fusions.

What is the fate of the adjacent segmental angles 6 months after single-level L3–4 or L4–5 lateral lumbar interbody fusion?

Background ContextLateral lumbar interbody fusion (LLIF) is an effective technique for fusion and sagittal alignment correction/maintenance. Studies have investigated the impact on the segmental angle and lumbar lordosis (and pelvic incidence-lumbar lordosis mismatch), however not much is documented regarding the immediate compensation of the adjacent angles. PurposeTo evaluate acute adjacent and segmental angle as well as lumbar lordosis changes in patients undergoing a L3–4 or L4–5 LLIF for degenerative pathology. Study Design/SettingRetrospective cohort study. Patient SamplePatients included in this study were analyzed pre- and post-LLIF performed by one of three fellowship-trained spine surgeons, 6 months following surgery. Outcome MeasuresPatient demographics (including body mass index, diabetes diagnosis, age, and sex) as well as VAS and ODI scores were measured. Lateral lumbar radiograph parameters: lumbar lordosis (LL), segmental lordosis (SL), infra and supra-adjacent segmental angle, and pelvic incidence (PI). MethodsMultiple regressions were applied for the main hypothesis tests. We examined any interactive effects at each operative level and used the 95% confidence intervals to determine significance: a confidence interval excluding zero indicates a significant effect. ResultsWe identified 84 patients who underwent a single level LLIF (61 at L4–5, 23 at L3–4). For both the overall sample and at each operative level, the operative segmental angle was significantly more lordotic postop compared to preop (all ps≤.01). Adjacent segmental angles were significantly less lordotic postop compared to pre-op overall (p=.001). For the overall sample, greater lordotic change at the operative segment led to more compensatory reduction of lordosis at the supra-adjacent segment. At L4–5, more lordotic change at the operative segment led to more compensatory lordosis reduction at the infra-adjacent segment. ConclusionThe present study demonstrated that LLIF resulted in significant increase in operative level lordosis and a compensatory decrease in supra- and infra-adjacent level lordosis, and subsequently no significant impact on spinopelvic mismatch.

Do On-Table Radiographs Predict Postoperative Sagittal Alignment after Posterior Lumbar Fusion?

To determine if intraoperative on-table lumbar lordosis and segmental lordosis correlate with postoperative lordosis following single-level posterolateral decompression and fusion (PLDF) or transforaminal lumbar interbody fusion (TLIF). Electronic medical records were reviewed for patients ≥18 years old who underwent PLDF or TLIF between 2012 and 2020. Lumbar lordosis and segmental lordosis were compared between pre-, intra-, and postoperative radiographs using paired t tests. Significance was set at P < 0.05. A total of 200 patients met inclusion criteria. No significant differences in preoperative, intraoperative, or postoperative measurements were found between groups. Patients who underwent PLDF experienced less disc height loss over 1 year postoperatively (PLDF: 0.45 ± 0.9 mm vs. TLIF: 1.2 ± 1.4 mm, P < 0.001). Lumbar lordosis significantly decreased between intraoperative to postoperative radiographs at 2-6 weeks for PLDF (Δ: -4.0°, P<0.001) and TLIF (Δ: -5.6°, P < 0.001), but no change was identified between the intraoperative and >6 month postoperative radiographs for PLDF (Δ: -0.3°, P= 0.634) or TLIF (Δ: -1.6°, P= 0.087). Segmental lordosis significantly increased from the preoperative to post-instrumentation intraoperative radiographs for PLDF (Δ: 2.7°, P < 0.001) and TLIF (Δ: 1.8°, P < 0.001), but it subsequently decreased at the final follow up for PLDF (Δ: -1.9°, P < 0.001) and TLIF (Δ: -2.3°, P < 0.001). Subtle decreases in lumbar lordosis may be noticed in early postoperative radiographs compared with intraoperative images on Jackson operative tables. However, these changes are not present at 1-year follow-up as lumbar lordosis increases to a similar level as intraoperative fixation.

Vertebral Body Sliding Osteotomy as a Surgical Strategy for the Treatment of Cervical Myelopathy: Outcomes at Minimum Five years Follow-up.

A retrospective cohort study. To evaluate the outcomes of vertebral body sliding osteotomy (VBSO) with a minimum follow-up of five years and compare the results with those of anterior cervical discectomy and fusion (ACDF) and anterior cervical corpectomy and fusion (ACCF). VBSO reportedly results in fewer complications, better lordosis restoration, and faster bone union than corpectomy. Although previous studies demonstrate the outcomes of VBSO with follow-up of two years or longer, results in longer term surveillance remain unknown. This study included 128 patients who underwent VBSO (n=38), ACDF (n=62), or ACCF (n=28) as a treatment for cervical myelopathy and was followed up for five years or more. Fusion, subsidence, C0-2 lordosis, C2-7 lordosis, segmental lordosis, C2-7 sagittal vertical axis, surgical complications, and neck pain visual analog scale, Neck Disability Index, and Japanese Orthopedic Association (JOA) scores were assessed. Comparisons between continuous variables in each group were made using independent sample t tests. For nominal variables, the Fisher exact test or the χ 2 test was used. Paired t test was used to analyze the changes in postoperative values compared with preoperative values. The reoperation rate (0.0%) after VBSO was significantly lower than that after ACCF (14.3%; P =0.028). VBSO had a higher fusion rate at six-month and one-year follow-up, but the fusion rate at five years (97.4%) was not significantly different from that of ACDF (85.5%; P =0.054) and ACCF (85.7%; P =0.077). Segmental lordosis at the five-year follow-up was significantly higher in the VBSO group (16.1°) than in the ACDF (11.9°; P =0.002) and ACCF (6.5°; P <0.001) groups. C2-7 lordosis at five-year follow-up was significantly higher in the VBSO group than in the ACCF group ( P =0.017). Neck pain visual analog scale, Neck Disability Index, and JOA scores and the JOA recovery rate did not show significant intergroup differences during the five-year study period. VBSO showed promising long-term results in terms of low revision rate, fast solid union, and effective segmental lordosis restoration when compared with other anterior reconstruction techniques.

Which Radiographic Parameter Can Aid in Deciding Optimal Allograft Height for Anterior Cervical Discectomy and Fusion?

Retrospective cohort study. To identify preoperative radiographic parameters that can guide optimal allograft height selection for anterior cervical discectomy and fusion (ACDF). Allograft height selection for ACDF depends on intraoperative assessment supported by trials; however, there is currently no radiographic reference parameter that could aid in allograft height selection for improved outcomes. A total of 148 patients who underwent ACDF using allografts and were followed up for more than 1 year were retrospectively reviewed. Fusion rates, subsidence, segmental lordosis, and foraminal height were assessed. Segments were divided into 2 groups according to whether the inserted allograft height was within 1mm from the following 3 reference radiographic parameters: (1) uncinate process height, (2) adjacent disc height, and (3) preoperative disc height +2mm. This study included 101 patients with 163 segments. Segments with an allograft-uncinate height difference of ≤1mm had a significantly higher fusion rate at 1-year follow-up compared with segments with allograft-uncinate height difference of >1mm [85/107 (79.4%) vs. 35/56 (62.5%); P =0.025]. Subsidence, segmental lordosis, and foraminal height did not significantly differ between the groups when segments were divided according to uncinate height. Multivariate logistic regression analysis demonstrated that allograft-uncinate height difference of ≤1mm and allograft failure were factors associated with fusion. The uncinate process height can guide optimal allograft height selection for ACDF. Using an allograft with an allograft-uncinate height difference of ≤1mm resulted in a higher fusion rate. Therefore, the uncinate process height should be checked preoperatively and used in conjunction with intraoperative assessment when selecting allograft height.

Surgical treatment of double major adolescent idiopathic scoliosis can lead to excessive lumbar lordosis in the instrumented segments.

The purpose of this study was to characterize the sagittal spine in AIS patients with double major curves fused into the lumbar spine to determine the effects of posterior spinal fusion and instrumentation (PSFI) on global and segmental lumbar sagittal parameters. A consecutive series of AIS patients undergoing a PSFI from 2012 to 2017 having Lenke 3, 4 or 6 curves were analyzed. Sagittal parameters included pelvic incidence (PI), lumbar lordosis (LL), and segmental lordosis were measured. The difference in segmental lumbar lordosis between the preoperative, 6-week, and 2-year radiographs was analyzed and correlated to outcomes using SRS-30 patient questionnaires. Seventy-seven patients had improvement in their coronal Cobb from 67.3 ± 11.8° to 25.43 ± 10.7° (66.4%) at 2years. There was no change in thoracic kyphosis (23.0 ± 13.4° to 20.3 ± 7.8°) and pelvic incidence (49.9 ± 13.4° to 51.1 ± 15.7°) from preoperative to 2years (p > 0.05) while lumbar lordosis increased from 57.6 ± 12.4° to 61.4° ± 12.3° (p = 0.002). Segmental lumbar analysis showed increased (+) lordosis at each instrumented level when comparing the preoperative and 2-year films for: T12-L1 (+ 3.24°, p < 0.001), L1-L2 (+ 5.70°, p < 0.001), and L2-L3 (+ 1.70°, p < 0.001). Loss (-) of lordosis was noted at every level below the LIV: L3-L4 (-1.70°, p < 0.001), L4-L5 (-3.52°, p < 0.001), L5-S1 (-1.98°, p = 0.02). Preoperative LL of L4-S1 comprised 70 ± 16% of the global LL compared to 56 ± 12%, at 2years (p < 0.001). Changes in sagittal measurements did not correlate with SRS outcome scores at two-year follow-up. When performing PSFI for double major scoliosis, global SVA was maintained at 2years, however, overall lumbar lordosis increased due to an increased lordosis in the instrumented segments and a smaller decrease in lordosis below the LIV. Surgeons should be wary of the tendency to create instrumented lumbar lordosis with a compensatory loss of lordosis below LIV which may be a set-up for poor long-term outcomes in adulthood.

Radiographic patterns and characteristics of sagittal profiles in normal spinopelvic curvatures: An explicit depiction of the distribution of lumbar vertebral bodies and discs.

The current study aimed to investigate the sagittal morphology of the spinopelvic complex and the components of the lumbar spine in the normal population. In total, 132 adult volunteers were retrospectively evaluated and divided into four groups according to the Roussouly classification. Statistical analysis of radiological parameters, including lumbar lordosis (LL), thoracic kyphosis (TK), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), PI-LL, LL-TK, lumbar vertebral lordosis from L1 to L5 (L1L-L5L), the intervertebral angle from L1-L2 to L5-S1 (IVA1-2-IVA5-1), segmental lordosis from L1 to L5 (S1L-S5L), the proportion of L1-L5 (L1%-L5%), the proportion of the intervertebral angle from L1-L2 to L5-S1 (IVA1-2%-IVA5-1%), and proportion of segmental lordosis from L1 to L5 (S1L%-S5L%), was performed. Based on the classification, type II (n=46) was the most common, followed by type I (n=39), type III (n=36), and type IV (n=11). The quantitative values of the sagittal parameters of the four groups were obtained. Results showed a significant difference in terms of LL, PI, SS, and LL-TK. Further, L1%, L2%, L3%, IVA1-2%, IVA2-3%, S1L%, S2L%, and S3L% had an increasing trend. PI was positively correlated with LL, S1L, S2L, S3L, S4L, S1L%, and S2L%, but not with S5L%. In conclusion, pelvic parameters had a significant effect on lumbar curvature and lordosis distribution. Further, the abovementioned results were beneficial for individual surgical decision-making regarding targeted intervertebral angle, screw-insertion dimension, and rod contouring.

Comparative Clinical Analysis of Oblique Lateral Interbody Fusion at L5/S1 versus Minimally Invasive Transforaminal Interbody Fusion (MIS-TLIF) for Degenerative Lumbosacral Disorders.

Since 2015, we have performed minimally invasive oblique lateral interbody fusion (OLIF) at L5/S1 for various lumbosacral spine disorders using percutaneous pedicle screws. This study evaluated the clinical and radiologic results between OLIF at L5/S1 and minimally invasive transforaminal interbody fusion (MIS-TLIF) for single to multilevel degenerative lumbosacral disorders. A total of 124 patients underwent either OLIF (62 cases) or MIS-TLIF (62 cases). The applied disorders were L5 isthmic spondylolisthesis, foraminal stenosis, pseudarthrosis, adjacent segment degeneration, a combination of L4/5 and L5/S1 pathology, and others. We performed OLIF with posterior percutaneous fixation in the same lateral position. MIS-TLIF was performed with modified cortical bone trajectory screws. The operation time (OT), estimated blood loss (EBL), JOABPEQ effectiveness rate (%),Visual Analog Scale (VAS), fusion rate, radiologic segmental alignment, and complications were evaluated. The average follow-up periods were 51 and 69 months (24-95) in the OLIF and MIS-TLIF groups, respectively. Furthermore, the average fused segments were 1.6 and 1.5 in each group, respectively. The OT and EBL per segment were 130 min and 56 mL and 100 min and 64 mL, respectively. The JOABPEQ effectiveness rate in the OLIF group demonstrated a statistically higher value in the domains of pain, low-back function, and gait than the MIS-TLIF group (P<0.01). The follow-up VAS of low-back pain (LBP) and lower extremity numbness had lower values in the OLIF group (P<0.05). The fusion rates were 98% and 90%, respectively. Segmental lordosis at L5/S1 was significantly larger in the OLIF group (15° vs. 11°, P<0.01). The OLIF group demonstrated less pain as well as better low-back and gait functions at follow-up. The minimally invasive anterolateral fusion employing OLIF at L5/S1 using percutaneous screws serves as a viable and effective procedure with less residual LBP and high fusion rate.

Comparison of Endoscopic and Minimally Invasive Transforaminal Lumbar Interbody Fusion for Lumbar Degenerative Diseases: A Meta-analysis.

Systematic review and meta-analysis. To compare the results of endoscopic transforaminal lumbar interbody fusion (Endo-TLIF) and minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) for patients with lumbar degenerative diseases. The MIS-TLIF has been widely used in lumbar degenerative diseases and achieved favorable clinical effects. The main disadvantage is the limited working space and visualization, especially in the deeper operational field, for preparing fusion bed. In recent years, with the development of surgical techniques, optical technology, and special instruments, Endo-TLIF has gradually been applied. A systematic review and meta-analysis of cohort studies between Endo-TLIF and MIS-TLIF in the lumbar degenerative diseases. The following outcome measures were extracted: visual analog scale (VAS), Oswestry Disability Index, fusion rate, disk height, segmental lordosis, operative time, length of hospital stay and complications. Data analysis was performed by RevMan 5.3. Eight studies comprising 687 patients were included in this meta-analysis. The pooled result revealed there was no significant differences in the VAS of leg, Oswestry Disability Index, fusion rate, disk height, segmental lordosis, and complication rate between the 2 groups ( P >0.05). However, the VAS of back in the Endo-TLIF group was significantly less than those in the MIS-TLIF group within 2 weeks after surgery [weighted mean difference (WMD)=-1.33 (-1.98, -0.68), P <0.0001] and at 3 months postoperatively [WMD=-0.72(-0.85, -0.59), P <0.00001]. The Endo-TLIF group also seemed to fewer VAS of back at the last follow-up (≥12mo) [WMD=-0.12 (-0.25, -0.00), P =0.05]. Compared with the MIS-TLIF group, the Endo-TLIF group was associated with longer operation time [WMD=26.74 (2.14, 51.34), P =0.03], but shorter length of hospital stay [WMD=-1.98(-2.91, -1.05), P <0.0001]. Compared with minimally invasive TLIF, endoscopic TLIF achieved comparable improvement of symptoms and intervertebral fusion, longer operation time, and smaller surgical trauma. Endoscopic TLIF, which requires a demanding learning curve, maybe a feasible and effective technique for the patients with symptomatic lumbar degenerative diseases.

Early Clinical Outcomes of the Prone Transpsoas Lumbar Interbody Fusion Technique.

The prone transpsoas (PTP) approach for lateral lumbar interbody fusion (LLIF) is a relatively novel technique. Currently, little is known about its associated complications and early patient-reported outcomes. The aim of this study was to investigate the effect of LLIF performed via the PTP approach on sagittal radiographic parameters, patient-reported outcome measures (PROMs), and rates of complications. A retrospective review was performed of 82 consecutive patients who underwent LLIF via a PTP technique. Lumbar lordosis (LL), segmental lordosis (SL), anterior disc height (ADH), and posterior disc height (PDH) were measured on preoperative, initial postoperative, and 3-month postoperative radiographs. PROMs including the Oswestry Disability Index (ODI); the visual analog scale (VAS); and pain portions of the EQ5D, VAS back, and VAS leg ratings were collected at the preoperative and subsequent postoperative visits. Length of hospital stay and postoperative complications related to the procedure were recorded. Significant improvements were seen at the initial (4.5° ± 8.6°, P < 0.001) and 3-month (4.4° ± 7.2°, P < 0.001) postoperative periods for LL, as well as SL (6.8° ± 4.8°, P < 0.001; 6.7° ± 4.4°, P < 0.001), ADH (8.0 mm ± 3.6, P < 0.001; 7.4 mm ± 3.6, P < 0.001), and PDH (3.3 mm ± 2.4, P < 0.001; 3.1 mm ± 2.5, P < 0.001). Significant improvements were seen at 3 months postoperatively for ODI (P < 0.001), EQ5D pain (P = 0.016), VAS leg (P < 0.001), and VAS back (P < 0.001). The average length of stay was 2.7 ± 4.5 days. The most common complications were ipsilateral thigh pain/numbness (45.1%), ipsilateral hip flexor weakness (39.0%), and contralateral thigh pain/numbness (14.6%). While early PROMs and correction of sagittal radiographic parameters show promising results for the PTP approach for LLIF, it is not without risks. PTP interbody fusion is an emerging technique that allows for simultaneous access to the anterior and posterior columns of the lumbar spine. This early case series demonstrates significant improvement in functional outcomes and lumbar lordosis with a safety profile comparable to other well-established techniques.