Risk factors of instrumentation failure and pseudarthrosis after stand-alone L5-S1 anterior lumbar interbody fusion: a retrospective cohort study

Clinical and Radiographic Outcomes of Anterior Lumbar Interbody Fusion With Anterior Plate Fixation

BACKGROUND

Reports on the outcomes following instrumented anterior lumbar interbody fusion (ALIF) with anterior plate fixation are limited. The aim of this study was to assess the clinical and radiographic outcomes of patients undergoing ALIF with anterior plate fixation.  Methods: Medical records and radiographic imaging were reviewed for 100 patients who received ALIF with anterior plate fixation between 2008 to 2021 and completed at least one year of follow-up and postoperative imaging. Prospectively collected patient data included indication for surgery, BMI, age, number and location of levels treated, complications, reoperation rates, fusion rate, and measurements of global lordosis, disc space height, and segmental angulation.  Results: A total of 100 patients were included in this study. The mean length of follow-up was 81.37 months. Changes in preoperative-to-postoperative Oswestry Disability Index (ODI) and Visual Analog Score (VAS) demonstrated improvements of 30.86% and 18.56%, respectively. Major vascular injuries occurred in 3% of the cases. A hardware failure rate of 5% was observed. The reoperation rate was 10%. The radiographic fusion rate derived from computed tomography (CT) and plain film was 95.45% and 88.87%, respectively. Postoperative global lordosis demonstrated a 6.08% increase. Postoperative segmental angulation measurements increased by 57.74%. No statistically significant differences in clinical or radiographic outcomes were observed based on the spine level of fusion or the number of fusions performed.  Conclusions: ALIF with anterior plate fixation achieved an adequate fusion rate with improvements in ODI and VAS scores meeting minimal clinically important difference thresholds. Postoperative disc space heights demonstrated significant improvements compared to preoperative measurements.

Endplate Trauma During Implant Insertion Affects the Expulsion Risk of Anterior Lumbar Interbody Fusion Devices

Background Anterior cage migration in anterior lumbar interbody fusion is a serious complication. To address this risk, cage designs are now available with integrated screw or blade fixation or specially designed surface geometries with large teeth or ridges. However, the implantation technique itself has not yet been addressed as a potential risk factor for cage migration. This study aimed to investigate whether a cage that is implantable without gouging the vertebral endplates has improved resistance to anterior migration. Methodology A novel three-piece modular cage was inserted between two vertebral body replacements (polyurethane (PU) foam grade 15 pcf) in two ways. In group 1 (modular), the cage was inserted in a wedge within a wedge fashion according to the manufacturer's instructions such that damage to the PU foam was minimized. In group 2 (mono-bloc), the modular cage was inserted pre-assembled as a one-piece, mono-bloc device. This insertion method required impaction and increased the potential of gouging the PU surfaces. Then, an axial preload was applied to the PU test blocks to simulate the preload on the spine in vivo and an anteriorly direct expulsion force was applied to the cages. Results The mean expulsion yield load in the test group with modular implantation was 392 ± 19 N compared to 287 ± 16 N in the test group where the mono-bloc implants were inserted and endplate gouging occurred. This difference was statistically significant (p < 0.05). Thus, the onset of cage migration occurred at significantly higher loads in the test group with modular insertion without endplate gouging compared to one-piece impaction with gouging taking place. In contrast, the stiffness and the ultimate load were similar in both test groups (p > 0.05). Conclusions This study showed that the cage insertion technique may have a significant effect on the cage migration risk. Prevention of endplate gouging during cage implantation has the potential to improve the primary stability of the cage.

OLIF versus ALIF: Which is the better surgical approach for degenerative lumbar disease? A systematic review

PURPOSE

The aim of this study was to compare the clinical and radiographical outcomes between OLIF and ALIF in treating lumbar degenerative diseases.

METHODS

We searched PubMed, Embase, Web of Science, and Cochrane Library for relevant studies. Changes in disc height (DH), segmental lordosis angle (SLA), lumbar lordosis (LL), visual analogue scale (VAS) score, and Oswestry disability index (ODI) between baseline and final follow-up, along with other important surgical outcomes, were assessed and analysed. Data on the global fusion rate and main complications were collected and compared.

RESULTS

Approximately, 2041 patients from 36 studies were included, consisting of 1057 patients who underwent OLIF and 984 patients who underwent ALIF. The results reveal no significant difference in DH, SLA, VAS score, and ODI between the two groups (all P > 0.05). The operation time, estimated blood loss, and length of hospital stay were also comparable between the two groups. Over 90% of the fusion rate was achieved in both groups. The OLIF group showed a higher complication rate than the ALIF group (OLIF 18.83% vs ALIF 7.32%).

CONCLUSIONS

OLIF leads to a higher complication rate, with the most notable complication being cage subsidence. Both OLIF and ALIF are effective treatments for degenerative lumbar diseases and have similar therapeutic effects. ALIF was expected to be more expensive for patients because of the necessity of involving vascular surgeons.

Trends of Different Surgical Approaches in Patients With Single-Level Lumbar Isthmic Spondylolisthesis: A National Registry Analysis

BACKGROUND

A variety of surgical approaches (anterior vs. posterior vs. anterior and posterior) are available for Isthmic Spondylolisthesis (IS). The aim of our study was to analyze the pattern and 30-day outcomes in patients undergoing different surgical approaches for single-level IS.

MATERIALS AND METHODS

National Surgical Quality Improvement Program (NSQIP) database was queried using the ICD-9/10 and CPT 4^th edition, from 2012 to 2020. We included patients 18-65 years of age who underwent spine fusions for IS. Outcomes were a length of stay (LOS), discharge disposition, 30-day complications, hospital readmission, and complication rates.

RESULTS

Of 1036 patients who underwent spine fusions for IS, 838 patients (80.8%) underwent posterior only, 115 patients (11.1%) underwent anterior-only fusions and the rest (8%) underwent combined anterior and posterior procedures. 60% of patients in the posterior-only cohort had at least one comorbidity compared to 54% of patients in anterior only and 55% of patients in the combined cohort. No statistically significant differences in terms of LOS (3 days each) and discharge to home (96% vs. 93% vs. 94%) were noted among the anterior-only, posterior-only and combined cohorts, p> 0.05. In terms of 30-day complication rates, combined procedures had slightly higher rates (13%) compared to anterior (10%) or posterior-only (9%) procedures.

CONCLUSION

Posterior-only fusions were performed in 80% of patients with IS. No differences in terms of LOS, discharge disposition to home, 30-day complications, hospital readmission and reoperation rates were noted across the cohorts.

A comparative study of L4-L5-S1 and L5-S1 vertebral fusion in high-grade L5-S1 spondylolisthesis

Introduction:

One of the most common types of spinal diseases is spondylolisthesis, which in advanced cases requires surgical intervention. This study aimed to compare the results of L4-L5-S1 and L5-S1 vertebral fusion treatment in high-grade L5-S1 spondylolisthesis.

Methods:

A study design that randomized controlled trial. A total of 70 consecutive patients who underwent surgery for the treatment of spondylolisthesis at Al-Zahra Hospital in Isfahan, Iran, were evaluated from July 2020 to February 2021 (35 patients underwent L4-L5-S1 and 35 received L5-S1 vertebral fusion treatment). The radicular and low back pain (LBP) intensity (Vanguard Australian Shares), blood loss, wound infection, reduction, and quality of life (SF-12 scores) were quantified before the surgery, 1, 3, and 6 months after surgery in two groups.

Results:

Patients involved in the two groups had similar baseline demographic characteristics. The percent slip in L4-L5-S1 and L5-S1 group, respectively, postoperative 81.11% and 57.89%, P = 0.0001. Intraoperative blood loss and postoperative were higher in the L4-L5-S1 group when compared to the L5-S1 group (P < 0.05). The wound infection rate of the L4-L5-S1 group was similar to that of the L5-S1 group (8.6% vs. 2.9%, P = 0.303). There was no difference in radicular and LBP intensity, SF-12 scores among patients with L4-L5-S1 and L5-S1 groups (P < 0.05).

Conclusion:

Both L4-L5-S1 and L5-S1 were equally beneficial in improving short-term functional outcomes for patients with high grade L5-S1 spondylolisthesis. However, L4-L5-S1 was associated with statistically significant higher incidences of blood loss, but it was accompanied by a better reduction. Therefore, caution should be exercised when considering L4-L5-S1.

A Technical Nuance to Avoid Lumbar Five Radiculopathy with Anterior Lumbar Fusion and Posterior Instrumentation

The anterior lumbar interbody fusion (ALIF) is a well-established procedure used to treat a multitude of spinal pathologies. When performed at the L5-S1 level, the ALIF is often supplemented with posterior pedicle screw and rod fixation. Because the interbody device can restore disk and foraminal height, one benefit of the ALIF procedure is indirect neural decompression in the spinal canal and neural foramina. If the contour of the posterior rod is not matched to the exact position of the tulip heads on the pedicle screws, spondylolisthesis can be introduced, leading to foraminal stenosis and nerve compression. This concern is particularly germane when the posterior instrumentation is placed percutaneously without any direct foraminal decompression. In this report, we describe a patient who had an L4-S1 ALIF, resulting in new L5-S1 retrolisthesis and worsening L5 radiculopathy. Technical nuances and avoidance strategies are discussed.

Implications of sagittal alignment and complication profile with stand-alone anterior lumbar interbody fusion versus anterior posterior lumbar fusion

Background

Anterior lumbar interbody fusion (ALIF) is commonly utilized in lumbar degenerative pathologies. Standalone ALIF (ST-ALIF) systems were developed to avoid added morbidity, surgical time, and cost of anterior and posterior fusion (APF). Controversy exists in the literature about which of these two techniques yields superior clinical and radiographic outcomes, and few studies have directly compared them. This study seeks to compare ST-ALIF and APF in terms of sagittal correction and surgical complications.

Methods

Ninty-two consecutive ALIF cases performed from 2013-2018 were retrospectively reviewed and separated into 2 groups. Radiographic measurements were performed on pre- and post-operative radiographs, including segmental lordosis (SL), lumbar lordosis (LL), and pelvic incidence-lumbar lordosis mismatch (PI-LL). Surgical complications were determined. Statistical analysis was performed using chi-square test of homogeneity, Fisher's exact test, and independent sample t-test. Comparisons between groups were deemed statistically significant at the P<0.05 threshold.

Results

Fifty-seven ST-ALIF, 35 APF were identified. There were no differences in age, gender, BMI, Charlson Comorbidity Index (CCI), preoperative diagnosis, or surgical level between the 2 cohorts. Bone Morphogenetic Protein (BMP) was utilized in 24.6% of ST-ALIF versus none of APF (P=0.001). No differences were detected in SL, LL, and PI-LL mismatch. ST-ALIF cohort had significantly greater risk of subsidence and revision surgery versus APF (12.3% vs. 0%, RD 95% CI: 3.8-20.8%, P=0.042). Recurrent spondylolisthesis occurred in 5 ST-ALIF cases, 3 cases with implant failure, and 2 nonunions versus none in the APF group.

Conclusions

ST-ALIF was associated with significantly greater subsidence and revision surgery versus APF. Careful patient selection is paramount when considering ST-ALIF. The potential for revision surgery may offset the potential benefit in avoiding posterior fusion. Despite the greater risk of subsidence, sagittal alignment was not significantly affected.

Surgical treatment of high-grade spondylolisthesis: Technique and results

Background

Surgical management of high-grade spondylolisthesis is not only challenging but also controversial, from in situ fusion to complete reduction. We report our results of a safe three-stage spinal procedure in a single surgical session with seven patients diagnosed high-grade spondylolisthesis.

Hypothesis

Posterior fixation combined with interbody fusion is effective on reduction, ossification and clinical outcomes in high-grade spondylolisthesis.

Patients and methods

This study is a retrospective review of patients who underwent surgery between 2016 and 2018. The surgical method involved specific installation for deformity reduction, pedicle screw fixation, correction of lumbosacral kyphosis with a specific distraction maneuver, wide decompression, gradual reduction of the deformity, and sometimes maintenance of the reduction with interbody fusion. Patients were checked out at 2, 6 and 12 months and yearly after the procedure. Clinical, radiological, Visual Analogic Scale (VAS) and Oswestry Disability Index (ODI) outcomes measures were collected.

Results

Seven patients with high-grade spondylolisthesis at L5-S1 (2 patients grade II, 4 patients grade IV and 1 patient grade V), with a median age of 37 years [17; 72] were included. Median follow-up was 24 months [12; 25 months]. All patients have a fused joint at 6 months except one. Median lumbosacral angle (LSA) improved from 76°[59; 85] to 94°[76; 104]. Meyerding grade of 2 cases was stable after surgery, 3 cases with loss of two ranks and 2 cases with loss of one rank. The radiological parameters showed statistically significant difference (p = 0.036) postoperatively. There was not deep infection. Medians VAS and ODI showed improved pain and disability scores.

Conclusion

This procedure allows correct reduction rate of high-grade spondylolisthesis with good clinic-radiologic outcomes. Though surgically demanding, it was safe and reproducible.

Level of evidence

IV, retrospective.