Surgical Treatment of Flat Back Syndrome With Anterior Hyperlordotic Cages

Sequential correction of sagittal vertical alignment and lumbar lordosis in adult flatback deformity

Background

Flatback deformity, or lumbar hypolordosis, can cause sagittal imbalance, causing back pain, fatigue, and functional limitation. Surgical correction through osteotomies and interbody fusion techniques can restore sagittal balance and relieve pain. This study investigated sagittal vertical alignment (SVA) and lumbar lordosis correction achieved through sequential procedures on human spine specimens.

Methods

Human T10-sacrum specimens were stratified into 2 groups: degenerative flatback specimens had smaller L1-S1 lordosis compared to the iatrogenic group (26.1°±15.0° vs. 47.8°±19.3°, p<.05). Specimens were mounted in the apparatus in simulated standing posture with a nominal sacral slope of 45 degrees and subjected to a 400N compressive follower preload. Sequential correction of degenerative lumbar flatback deformity involved: anterior lumbar interbody fusion (ALIF) at L5-S1, ALIF at L4-5, lateral lumbar interbody fusion (LLIF) at L2-3 and L3-4, and posterior column osteotomy (PCO) at L2-3 and L3-4. In iatrogenic specimens, flatback deformity was created by performing a posterior in-situ immobilization using pedicle screw instrumentation at L4-L5-S1 followed by distraction across the pedicle screws. We then performed LLIF at L2-3 and L3-4, followed by PCO at L2-3 and L3-4.

Results

Statistically significant incremental corrections were noted in SVAs and lordosis after L5-S1 ALIF, L4-5 ALIF, and PCO in degenerative flatback specimens. For the iatrogenic group, statistically significant worsening was noted in measures of standing alignment after L4-L5-S1 hypolordotic fusion. Subsequent LLIF at L2-3 and L3-4 did not significantly improve sagittal alignment. However, after PCO at L2-3 and L3-4, final alignment parameters were not significantly different than preoperative baseline values prior to hypolordotic fusion.

Conclusions

ALIF cages in the lower lumbar segments significantly improved sagittal alignment in degenerative flatback specimens. In the upper lumbar segments, LLIF cages alone were ineffective at enhancing lumbar lordosis. LLIF cages in conjunction with PCO improved alignment parameters in degenerative and iatrogenic flatback deformities.

Pedicle Subtraction Osteotomy Versus Multilevel Anterior Lumbar Interbody Fusion and Lateral Lumbar Interbody Fusion in the Treatment of Adult Spinal Deformity: Trends, Outcomes, and Cost

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The aim of this study was to compare the outcomes of pedicle subtraction osteotomy (PSO) with multilevel anterior lumbar interbody fusion (ALIF) and lateral lumbar interbody fusion (LLIF) in posterior long-segment fusion.

BACKGROUND

PSO and ALIF/LLIF are 2 techniques used to restore lumbar lordosis and correct sagittal alignment, with each holding its unique advantages and disadvantages. As there are situations where both techniques can be employed, it is important to compare the risks and benefits of both.

PATIENTS AND METHODS

Patients aged 18 years or older who underwent PSO or multilevel ALIF/LLIF with posterior fusion of 7-12 levels and pelvic fixation were identified. 1:1 propensity score was used to match PSO and ALIF/LLIF cohorts for age, sex, and relevant comorbidities, including smoking status. Logistic regression was used to compare medical and surgical outcomes. Trends and costs were generated for both groups as well.

RESULTS

ALIF/LLIF utilization in posterior long fusion has been steadily increasing since 2010, whereas PSO utilization has significantly dropped since 2017. PSO was associated with an increased risk of durotomy ( P < 0.001) and neurological injury ( P = 0.018). ALIF/LLIF was associated with increased rates of postoperative radiculopathy ( P = 0.005). Patients who underwent PSO had higher rates of pseudarthrosis within 1 and 2 years ( P = 0.015; P = 0.010), 1-year hardware failure ( P = 0.028), and 2-year reinsertion of instrumentation ( P = 0.009). Reoperation rates for both approaches were not statistically different at any time point throughout the 5-year period. In addition, there were no significant differences in both procedural and 90-day postoperative costs.

CONCLUSIONS

PSO was associated with higher rates of surgical complications compared with anterior approaches. However, there was no significant difference in overall reoperation rates. Spine surgeons should select the optimal technique for a given patient and the type of lordotic correction required.

Influences of lumbo-sacral transitional vertebrae for anterior lumbar interbody fusion

Lumbo-sacral transitional vertebrae (LSTV) are frequent congenital variances of the spine and are associated with increased spinal degeneration. Nevertheless, there is a lack of data whether bony alterations associated with LSTV result in reduced segmental restoration of lordosis when performing ALIF. 58 patients with monosegmental stand-alone ALIF in the spinal segment between the 24th and 25th vertebra (L5/S1)/(L5/L6) where included. Of these, 17 patients had LSTV and were matched to a control population by age and sex. Pelvic incidence, pelvic tilt, sagittal vertical axis, lumbar lordosis, segmental lordosis, disc height and depth were compared. LSTV-patients had a significantly reduced segmental lordosis L4/5 (p = 0.028) and L5/S1/(L5/L6) (p = 0.041) preoperatively. ALIF resulted in a significant increase in segmental lordosis L5/S1 (p < 0.001). Postoperatively, the preoperatively reduced segmental lordosis was no longer significantly different in segments L4/5 (p = 0.349) and L5/S1/(L5/6) (p = 0.576). ALIF is associated with a significant increase in segmental lordosis in the treated segment even in patients with LSTV. Therefore, ALIF is a sufficient intervention for restoring the segmental lordosis in these patients as well.

The Role of Anterior Spine Surgery in Deformity Correction

There are a range of anterior-based approaches to address flexible adult spinal deformity from the thoracic spine to the sacrum, with each approach offering access to a range of vertebral levels. It includes the transperitoneal (L5-S1), paramedian anterior retroperitoneal (L3-S1), oblique retroperitoneal (L1-2 to L5-S1), the thoracolumbar transdiaphragmatic approach (T9-10 to L4-5), and thoracotomy approach (T4-T12). The lumbar and lumbosacral spine is especially favorable for anterior-based approaches given the relative mobility of the peritoneal organs and position of the vasculature.

Three-Column Osteotomy in Adult Spinal Deformity: An Analysis of Temporal Trends in Usage and Outcomes

BACKGROUND

Three-column osteotomies (3COs), usually in the form of pedicle subtraction or vertebral column resection, have become common in adult spinal deformity surgery. Although a powerful tool for deformity correction, 3COs can increase the risks of perioperative morbidity.

METHODS

Operative patients with adult spinal deformity (Cobb angle of >20°, sagittal vertical axis [SVA] of >5 cm, pelvic tilt of >25°, and/or thoracic kyphosis of >60°) with available baseline and 2-year radiographic and health-related quality-of-life (HRQoL) data were included. Patients were stratified into 2 groups by surgical year: Group I (2008 to 2013) and Group II (2014 to 2018). Patients with 3COs were then isolated for outcomes analysis. Severe sagittal deformity was defined by an SVA of >9.5 cm. Best clinical outcome (BCO) was defined as an Oswestry Disability Index (ODI) of <15 and Scoliosis Research Society (SRS)-22 of >4.5. Multivariable regression analyses were used to assess differences in surgical, radiographic, and clinical parameters.

RESULTS

Seven hundred and fifty-two patients with adult spinal deformity met the inclusion criteria, and 138 patients underwent a 3CO. Controlling for baseline SVA, PI-LL (pelvic incidence minus lumbar lordosis), revision status, age, and Charlson Comorbidity Index (CCI), Group II was less likely than Group I to have a 3CO (21% versus 31%; odds ratio [OR] = 0.6; 95% confidence interval [CI] = 0.4 to 0.97) and more likely to have an anterior lumbar interbody fusion (ALIF; OR = 1.6; 95% CI = 1.3 to 2.3) and a lateral lumbar interbody fusion (LLIF; OR = 3.8; 95% CI = 2.3 to 6.2). Adjusted analyses showed that Group II had a higher likelihood of supplemental rod usage (OR = 21.8; 95% CI = 7.8 to 61) and a lower likelihood of proximal junctional failure (PJF; OR = 0.23; 95% CI = 0.07 to 0.76) and overall hardware complications by 2 years (OR = 0.28; 95% CI = 0.1 to 0.8). In an adjusted analysis, Group II had a higher likelihood of titanium rod usage (OR = 2.7; 95% CI = 1.03 to 7.2). Group II had a lower 2-year ODI and higher scores on Short Form (SF)-36 components and SRS-22 total (p < 0.05 for all). Controlling for baseline ODI, Group II was more likely to reach the BCO for the ODI (OR = 2.8; 95% CI = 1.2 to 6.4) and the SRS-22 total score (OR = 4.6; 95% CI = 1.3 to 16).

CONCLUSIONS

Over a 10-year period, the rates of 3CO usage declined, including in cases of severe deformity, with an increase in the usage of PJF prophylaxis. A better understanding of the utility of 3CO, along with a greater implementation of preventive measures, has led to a decrease in complications and PJF and a significant improvement in patient-reported outcome measures.

LEVEL OF EVIDENCE

Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Anterior spine surgery for the treatment of complex spine pathology: a state-of-the-art review

The use of anterior spinal surgery for the treatment of spinal pathology has experienced a dramatic increase over the past decade. Long relegated to treat complicated anterior pathologies it has returned to mainstream spine surgery techniques for all types of conditions, providing a significant boost to the spine surgeons' armamentarium to address a wide variety of types of spinal diseases more effectively. Anterior surgery is useful whenever there is significant spinal pathology that requires direct visualization of the anterior vertebral column to best restore spinal alignment, structural integrity and neurologic function. These pathologies include spinal deformities, tumors, burst fractures, infections, vertebral avascular necrosis, pseudoarthrosis and other miscellaneous indications. Currently available approaches to the spine include transabdominal, paramedian retroperitoneal, lateral oblique retroperitoneal, thoracotomy, and thoracolumbar extensile. Most of the lumbar approaches are now done through a muscle splitting, minimalistic approach that has decreased their morbidity or more recently via tubular approaches, such as lateral lumbar interbody fusions or other ante-psoas approaches. New retractors, instrumentation, hyperlordotic implants, approved biologics and even image guidance for disc preparation and precise implant placement are all recent advances that will hopefully improve surgical outcomes in patients following anterior spinal surgery. Most importantly, these approaches require added expertise and training with a dedicated team consisting of an anteriorly trained spine surgeon working simultaneously with a dedicated vascular surgeon to ensure maximum safety and superior patient outcomes. This state of the review is dedicated to familiarizing practicing spine surgeons with the most commonly used anterior spinal approaches along with cutting-edge instrumentation and fusion techniques to improve their options for the treatment of difficult spinal pathologies.

Post-operative L5 radiculopathy after L5-S1 hyperlordotic anterior lumbar interbody fusion (HL-ALIF) is related to a greater increase of lordosis and smaller post-operative posterior disc height: results from a cohort study

STUDY DESIGN

A single-centre retrospective study.

BACKGROUND AND PURPOSE

This study aims to investigate the rate of L5 radiculopathy, to identify imaging features associated with the complication and to evaluate the clinical outcomes in adult spine deformity patients undergoing L5-S1 ALIF with hyperlordotic cages.

METHODS

Design: retrospective cohort study. A single-centre prospective database was queried to analyse patients undergoing hyperlordotic (HL) ALIF with posterior fusion to correct spinal deformity. Clinical status was evaluated by back and leg pain numeric rate scale and Oswestry Disability Index pre-operatively and at 3-, 6- and 12-month follow-up. Spinopelvic parameters, such as pelvic incidence, pelvic tilt, lumbar lordosis and L5-S1 lordosis, posterior disc height (PDH) and anterior disc height, were assessed pre-operatively and post-operatively on standardized full-spine standing EOS images. The sagittal foraminal area was measured pre- and post-operatively on a CT scan.

RESULTS

Thirty-nine patients with a mean age of 63.2 ± 8.6 years underwent HL-ALIF from January 2016 to December 2019. Seven of them developed post-operative root pain (5) or weakness (2) (Group A), while thirty-two did not (Group B). Root impairment was associated with greater segmental correction magnitude, 26° ± 11.1 in Group A versus 15.1° ± 9.9 in Group B (p < 0.05), and to smaller post-operative PDH, 5.9 mm ± 2.7 in Group A versus 8.3 mm ± 2.6 (p < 0.05).

CONCLUSIONS

Post-operative root problems were observed in 17.9% of patients undergoing HL-ALIF for adult spine deformity. L5 radiculopathy was associated with larger sagittal angular corrections and smaller post-operative posterior disc height. One patient (2.6%) needed L5 root decompression. At 12 months of follow-up, results were equivalent between groups.

LEVEL OF EVIDENCE I

Diagnostic: individual cross-sectional studies with the consistently applied reference standard and blinding.

Novel Applications of Spinal Navigation in Deformity and Oncology Surgery-Beyond Screw Placement

Computer-assisted navigation has made a major impact on spine surgery, providing surgeons with technological tools to safely place instrumentation anywhere in the spinal column. With advances in intraoperative image acquisition, registration, and processing, many surgeons are now using navigation in their practices. The incorporation of navigation into the workflow of surgeons continues to expand with the evolution of minimally invasive techniques and robotic surgery. While numerous investigators have demonstrated the benefit of navigation for improving the accuracy of instrumentation, few have reported applying this technology to other aspects of spine surgery. Surgeries to correct spinal deformities and resect spinal tumors are technically demanding, incorporating a wide range of techniques not only for instrumentation placement but also for osteotomy planning and executing the goals of surgery. Although these subspecialties vary in their objectives, they share similar challenges with potentially high complications, invasiveness, and consequences of failed execution. Herein, we highlight the utility of using spinal navigation for applications beyond screw placement: specifically, for planning and executing osteotomies and guiding the extent of tumor resection. A narrative review of the work that has been done is supplemented with illustrative cases demonstrating these applications.

ALIF in the correction of spinal sagittal misalignment. A systematic review of literature

PURPOSE

We aim at analysing the impact of anterior lumbar interbody fusion (ALIF) in restoring the main spinopelvic parameters, along with its potentials and limitations in correcting sagittal imbalance.

MATERIALS AND METHODS

The 2009 PRISMA flow chart was used to systematically review the literature; 27 papers were eventually selected. The following spinopelvic parameters were observed: pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), segmental lumbar lordosis (LLseg) and sagittal vertical axis (SVA). Papers reporting on hyperlordotic cages (HLC) were analysed separately. The indirect decompression potential of ALIF was also assessed. The clinical outcome was obtained by collecting visual analogue scale (VAS) for back and leg pain and Oswestry Disability Index (ODI) scores. Global fusion rate and main complications were collected.

RESULTS

PT, SS, LL, LLseg and SVA spinopelvic parameters all improved postoperatively by - 4.3 ± 5.2°, 3.9 ± 4.5°, 10.6 ± 12.5°, 6.7 ± 3.5° and 51.1 ± 44.8 mm, respectively. HLC were statistically more effective in restoring LL and LLseg (p < 0.05). Postoperative disc height, anterior disc height, posterior disc height and foraminal height, respectively, increased by 58.5%, 87.2%, 80.9% and 18.1%. Postoperative improvements were observed in VAS back and leg and ODI scores (p < 0.05). The global fusion rate was 94.5 ± 5.5%; the overall complication rate was 13%.

CONCLUSION

When managing sagittal imbalance, ALIF can be considered as a valid technique to achieve the correct spinopelvic parameters based on preoperative planning. This technique permits to obtain an optimal LL distribution and a solid anterior column support, with lower complications and higher fusion rates when compared to posterior osteotomies.