Improvement of coronal alignment in fractional low lumbar curves with the use of anterior interbody devices

Assessing the Fractional Curve for Proper Management of Adult Degenerative Scoliosis

Adult degenerative scoliosis (ADS) is a coronal plane deformity often accompanied by sagittal plane malalignment. Surgical correction may involve the major and/or distally-located fractional curves (FCs). Correction of the FC has been increasingly recognized as key to ameliorating radicular pain localized to the FC levels. The present study aims to summarize the literature on the rationale for FC correction in ADS. Three databases were systematically reviewed to identify all primary studies reporting the rationale for correcting the FC in ADS. Articles were included if they were English full-text studies with primary data from ADS ( ≥ 18 years old) patients. Seventy-four articles were identified, of which 12 were included after full-text review. Findings suggest FC correction with long-segment fusion terminating at L5 increases the risk of distal junctional degeneration as compared to constructs instrumenting the sacrum. Additionally, circumferential fusion offers greater FC correction, lower reoperation risk, and shorter construct length. Minimally invasive surgery (MIS) techniques may offer effective radiographic correction and improve leg pain associated with foraminal stenosis on the FC concavity, though experiences are limited. Open surgery may be necessary to achieve adequate correction of severe, highly rigid deformities. Current data support major curve correction in ASD where the FC concavity and truncal shift are concordant, suggesting that the FC contributes to the patient's overall deformity. Circumferential fusion and the use of kickstand rods can improve correction and enhance the stability and durability of long constructs. Last, MIS techniques show promise for milder deformities but require further investigation.

Coronal Alignment in Adult Spine Surgery

Coronal realignment is an important goal in adult spine surgery that has been overshadowed by emphasis on the sagittal plane. As coronal malalignment drives considerable functional disability, a fundamental understanding of its clinical and radiographic evaluation and surgical techniques to prevent its development is of utmost importance. In this study, we review etiologies of coronal malalignment and their radiographic and clinical assessments, risk factors for and functional implications of postoperative coronal malalignment, and surgical strategies to optimize appropriate coronal realignment in adult spine surgery.

Anterior lumbar interbody fusion versus transforaminal lumbar interbody fusion for correction of lumbosacral fractional curves in adult (thoraco)lumbar scoliosis: A systematic review

Background

Anterior lumbar interbody fusion (ALIF) or transforaminal lumbar interbody fusion (TLIF) may be used to correct the lumbosacral fractional curve (LsFC) in de novo adult (thoraco) lumbar scoliosis. Yet, the relative benefits of ALIF and TLIF for LsFC correction remain largely undetermined.

Purpose

To compare the currently available data comparing radiographic correction of the LsFC provided by ALIF and TLIF of LsFC in adult (thoraco)lumbar scoliosis.

Methods

A systematic review was performed on original articles discussing fractional curve correction of lumbosacral spinal deformity (using search criteria: "lumbar" and "fractional curve"). Articles which discussed TLIF or ALIF for LsFC correction were presented and radiographic results for TLIF and ALIF were compared.

Results

Thirty-one articles were returned in the original search criteria, with 7 articles included in the systematic review criteria. All 7 articles presented radiographic results using TLIF for LsFC correction. Three of these articles also discussed results for patients whose LsFC were treated with ALIFs; 2 articles directly compared TLIF and ALIF for LsFC correction. Level III and level IV evidence indicated ALIF as advantageous for reducing the coronal Cobb angle of the LsFC. There were mixed results on relative efficacy of ALIF and TLIF in the LsFC for restoration of adequate global coronal alignment.

Conclusions

Limited level III and IV evidence suggests ALIF as advantageous for reducing the coronal Cobb angle of the LsFC in de novo adult (thoraco) lumbar scoliosis. Relative efficacy of ALIF and TLIF in the LsFC for restoration of global coronal alignment may be dictated by several factors, including directionality and magnitude of preoperative coronal deformity. Given the limited and low-quality evidence, additional research is warranted to determine the ideal interbody support strategies to address the LsFC in adult (thoraco) lumbar scoliosis.

Oblique lateral interbody fusion for lumbosacral fractional curve correction in degenerative lumbar scoliosis

PURPOSE

In combined anterior-posterior adult spinal deformity surgery, the optimal combination of anterior and posterior procedures remains unclear. We aimed to demonstrate the radiological outcomes and relevant factors in oblique lateral interbody fusion (OLIF) for lumbosacral fractional curve (FC) correction combined with open posterior surgery in degenerative lumbar scoliosis (DLS).

METHODS

This study involved 42 consecutive patients with DLS who had a major curve (MC) ≥ 20° and an FC (L4 to S1) ≥ 10°, and underwent a combined anterior-posterior surgery Changes in the MC, FC, coronal balance distance, type of coronal imbalance, coronal/sagittal disc angle at L4-5 and L5-S1, L4 and L5 tilt, and sagittal parameters were examined. The associations between FC correction and demographic, surgical, and radiological factors were analysed.

RESULTS

The FC decreased from 16.9 ± 7.3° preoperatively to 6.6 ± 4.4° at the last follow-up (P < 0.001). The coronal disc angle at L4-5 and L5-S1 were, respectively, 6.8 ± 2.2° and 6.0 ± 4.1° preoperatively and decreased to 2.2 ± 2.1 and 1.2 ± 1.3° at the last follow-up (both P < 0.001). The changes in FC were greater in uppermost instrumented level > T10 (P < 0.001), and associated with the preoperative FC (r = 0.820, P < 0.001), L4 tilt (r = 0.434, P = 0.007), and L5 tilt (r = 0.462, P = 0.003).

CONCLUSION

OLIF at the FC combined with open posterior surgery is an effective combined anterior-posterior correction strategy in DLS.

Clinical and Radiologic Analysis of Minimally Invasive Anterior-Posterior Combined Surgery for Adult Spinal Deformity: Comparison of Oblique Lateral Interbody Fusion at L5/S1 (OLIF51) versus Transforaminal Interbody Fusion

Background and Objectives: Although adult spinal deformity (ASD) surgery brought about improvement in the quality of life of patients, it is accompanied by high invasiveness and several complications. Specifically, mechanical complications of rod fracture, instrumentation failures, and pseudarthrosis are still unsolved issues. To better improve these problems, oblique lateral interbody fusion at L5/S1 (OLIF51) was introduced in 2015 at my institution. The objective of this study was to compare the clinical and radiologic outcomes of anterior-posterior combined surgery for ASD between the use of OLIF51 and transforaminal interbody fusion (TLIF) at L5/S1. Materials and Methods: A total of 117 ASD patients received anterior-posterior correction surgeries either with the use of OLIF51 (35 patients) or L5/S1 TLIF (82 patients). In both groups, L1-5 OLIF and minimally invasive posterior procedures of hybrid or circumferential MIS were employed. The sagittal and coronal spinal alignment and spino-pelvic parameters were recorded preoperatively and at follow-up. The quality-of-life parameters and visual analogue scale were evaluated, as well as surgical complications at follow-up. Results: The average follow-up period was thirty months (13-84). The number of average fused segments was eight (4-12). The operation time and estimated blood loss were significantly lower in OLIF51 than in TLIF. The PI-LL mismatch, LLL, L5/S1 segmental lordosis, and L5 coronal tilt were significantly better in OLIF51 than TLIF. The complication rate was statistically equivalent between the two groups. Conclusions: The introduction of OLIF51 for adult spine deformity surgery led to a decrease in operation time and estimated blood loss, as well as improvement in sagittal and coronal correction compared to TLIF. The circumferential MIS correction and fusion with OLIF51 serve as an effective surgical modality which can be applied to many cases of adult spinal deformity.

The Lumbosacral Fractional Curve vs Maximum Coronal Cobb Angle in Adult Spinal Deformity Patients with Coronal Malalignment: Which Matters More?

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

In patients undergoing adult spinal deformity (ASD) surgery we sought to: 1) report preoperative and postoperative lumbosacral fractional (LSF) curve and maximum coronal Cobb angles and 2) determine their impact on radiographic, clinical, and patient-reported outcomes (PROs).

METHODS

A single-institution cohort study was undertaken. The LSF curve was the cobb angle between the sacrum and most tilted lower lumbar vertebra. Coronal/sagittal vertical axis (CVA/SVA) were collected. Patients were compared between 4 groups: 1) Neutral Alignment (NA); 2) coronal malalignment only (CM); 3) Sagittal malalignment only (SM); and 4) Combined-Coronal-Sagittal-Malalignment (CCSM). Outcomes including postoperative CM, postoperative coronal vertical axis, complications, readmissions, reoperation, and PROs.

RESULTS

A total of 243 patients underwent ASD surgery with mean total instrumented levels of 13.5. Mean LSF curve was 12.1±9.9°(0.2-62.3) and mean max Cobb angle was 43.0±26.5° (0.0-134.3). The largest mean LSF curves were seen in patients with CM (14.6°) and CCSM (13.1°) compared to NA (12.1°) and SM (9.5°) (p=0.100). A higher LSF curve was seen in patients with fusion to the sacrum and instrumentation to the pelvis (p=0.009), and a higher LSF curve was associated with more TLIFs (p=0.031). Postoperatively, more TLIFs were associated with greater amount of LSF curve correction (p<0.001). Comparing the LSF and the max Cob angle among Qiu types, the highest mean max Cobb angle was in Qiu Type B patients (p=0.025), whereas the highest mean LSF curve was in Qiu Type C patients (p=0.037). Moreover, 82.7% of patients had a LSF curve opposite the max Cobb angle. The LSF curve was larger than the max Cobb angle in 22/243 (9.1%) patients, and most of these 22 patients were Qiu Type A (59.1%). Regarding correction, the max Cobb angle achieved more correction than the LSF curve, judged by the percent improved from preop (54.5% Cobb vs. 46.5% LSF, p=0.025) in patients with max cobb>20° and LSF curve >5°. The LSF curve underwent greater correction in Qiu Type C patients (9.2°) compared to Type A (5.7°) and Type B (5.1°) (p=0.023); however, the max Cobb angle was similarly corrected among Qiu Types: Type A 21.8°, Type B 24.6°, and Type C 25.4° (p=0.602). Minimal differences were seen comparing the preop/postop/change in LSF curve and max Cobb angle regarding postop CM, postop CVA, complications, readmissions, reoperation, and PROs.

CONCLUSIONS

The LSF curve was highest in patients with CM, CCSM, and Qiu Type C curves. Most patients had a LSF curve opposite the max Cobb angle. The max Cobb angle was more often corrected than the LSF curve. The LSF curve underwent greater correction among Qiu Type C patients, whereas the max Cobb angle was similarly corrected among all Qiu Types. No clear trend was seen regarding postoperative complications and PROs between the LSF curve and max Cobb angle.