Rod fractures and nonunions after long fusion to the sacrum for primary presentation adult spinal deformity: a comparison with and without interbody fusion in the distal lumbar spine

Utilization of L5-S1 interbody cage in adult spinal deformity patients undergoing lumbar spinal osteotomies and spinopelvic fixation: A retrospective comparative study

Background

Adult spinal deformity (ASD) surgeries often face complications, such as pseudoarthrosis and rod fractures (RFs), particularly at the lumbosacral junction. While transforaminal lumbosacral interbody fusion (TLIF) at L5-S1 is thought to improve outcomes, its efficacy in major ASD surgeries remains unclear. This study aims to compare clinical and radiological outcomes and implant complications in patients undergoing spinopelvic fixation with or without L5-S1 TLIF.

Methods

A retrospective cohort study was conducted, including 157 ASD patients who underwent high-grade osteotomies and spinopelvic fixation from 2021 to 2024. Patients were divided into two groups: those with L5-S1 TLIF (C group, n = 71) and those without (NC group, n = 86). Outcomes included rod fracture (RF) rate, sagittal alignment, and patient-reported measures such as the Visual Analog Scale (VAS), Oswestry disability index (ODI), and 36-Item Short Form Survey (SF-36), assessed at baseline, 1, 6, and 12 months postoperatively.

Results

RFs were significantly lower in the C group (4% vs. 13%, P = 0.03). Improved postoperative sagittal vertical axis and pelvic tilt were noted in the C group (P < 0.01). Both VAS and ODI scores were significantly better at 6 and 12 months in the C group (P < 0.01), along with higher SF-36 scores. No significant differences in baseline characteristics, estimated blood loss, or operation time were observed.

Conclusion

The use of L5-S1 TLIF reduces RF rates, improves sagittal alignment, and clinical outcomes in ASD surgery. Incorporating TLIF at L5-S1 may optimize outcomes without increasing perioperative risks.

Use of Supplemental Rod Constructs in Adult Spinal Deformity Surgery: A Review

Adult spinal deformity comprises a heterogeneous group of disorders that primarily affects older patients and can have a significant negative affect on health-related quality of life. Operative treatment for adult spinal deformity typically entails posterior instrumented fusions that have demonstrated the potential to significantly improve health-related quality of life outcomes. However, until fusion is achieved, the instrumentation providing structural support is subject to repetitive cyclical loading that disproportionately fatigues high-stress areas and can result in instrumentation failure. Despite considerable advances in surgical fixation techniques and technology, pseudarthrosis with subsequent implant failure still poses a challenge for surgeons and continues to be 1 of the most common complications, leading to revision surgery. The addition of supplemental rods to primary constructs has gained widespread popularity to mitigate implant failure. Theoretically, more rods will add stiffness, stability, and decreased surface strain, which will provide longer instrumentation lifespan to allow for osseous fusion. There is significant heterogeneity in these constructs, and different types of supplemental rods (eg, satellite, accessory, delta rods, "kickstand rod," and "iliac accessory rod") can be used independently or in combination to further increase strength. However, the use of supplemental rods may increase the rate of proximal junctional kyphosis/failure and paradoxically diminish anterior column fusion rates. Hence, indications and optimal configurations are still a matter of debate. The aim of this narrative review is to provide an overview of the supplemental rod constructs described in the literature and focus on the current evidence supporting their indications and potential impact.

Readmission rate after adult scoliosis surgery on primary cases over 45 years-old with long term follow-up

PURPOSE

Scoliosis surgery is becoming increasingly frequent. Rate of readmission is little discussed in the literature. It is an interesting data for the patient's information and for public authorities to calculate cost-effectiveness. Aim of the study was to evaluate rate and causes of short and long-term readmissions in patients > 45 years old operated on for a scoliosis primary cases, then to look for predictors of these readmissions.

METHODS

In this monocentric retrospective cohort study, over 45 years-old scoliosis primary cases operated on between 2015 and 2018 and with a minimum of 2 years follow-up were included. The number of readmissions and their causes were analyzed. Rehospitalized patients (RH) were then compared to non-rehospitalized patients (NRH). Risk factors were sought using a multivariate analysis by logistic regression.

RESULTS

105 patients were included (90% female; 64 ± 8 years). 56% were readmitted at least once. Main cause of readmission as pseudarthrosis (70%). Among the RH patients, fifty-eight required at least one revision. We found no significant difference between RH and NRH, apart from the rate of immediate post-operative medical complications which was significantly higher in RH (17% (n = 11) vs. 4% (n = 2), p = 0.04). According to multivariate analysis, BMI and age were found as predictors of readmission of mechanical origin, and BMI for readmissions of septic origin.

CONCLUSION

The readmission rate after scoliosis surgery was 56%. The main cause was pseudarthrosis. Rehospitalized patients had more immediate post-operative medical complications. The elderly and overweight patients are more likely to be readmitted for mechanical or septic reasons.

Spinopelvic fixation failure in the adult spinal deformity population: systematic review and meta-analysis

INTRODUCTION

Despite modern fixation techniques, spinopelvic fixation failure (SPFF) after adult spinal deformity (ASD) surgery ranges from 4.5 to 38.0%, with approximately 50% requiring reoperation. Compared to other well-studied complications after ASD surgery, less is known about the incidence and predictors of SPFF.

AIMS/OBJECTIVES

Given the high rates of SPFF and reoperation needed to treat it, the purpose of this systematic review and meta-analysis was to report the incidence and failure mechanisms of SPF after ASD surgery.

MATERIALS/METHODS

The literature search was executed across four databases: Medline via PubMed and Ovid, SPORTDiscus via EBSCO, Cochrane Library via Wiley, and Scopus. Study inclusion criteria were patients undergoing ASD surgery with spinopelvic instrumentation, report rates of SPFF and type of failure mechanism, patients over 18 years of age, minimum 1-year follow-up, and cohort or case-control studies. From each study, we collected general demographic information (age, gender, and body mass index), primary/revision, type of ASD, and mode of failure (screw loosening, rod breakage, pseudarthrosis, screw failure, SI joint pain, screw protrusion, set plug dislodgment, and sacral fracture) and recorded the overall rate of SPF as well as failure rate for each type. For the assessment of failure rate, we required a minimum of 12 months follow-up with radiographic assessment.

RESULTS

Of 206 studies queried, 14 met inclusion criteria comprising 3570 ASD patients who underwent ASD surgery with pelvic instrumentation (mean age 65.5 ± 3.6 years). The mean SPFF rate was 22.1% (range 3-41%). Stratification for type of failure resulted in a mean SPFF rate of 23.3% for the pseudarthrosis group; 16.5% for the rod fracture group; 13.5% for the iliac screw loosening group; 7.3% for the SIJ pain group; 6.1% for the iliac screw group; 3.6% for the set plug dislodgement group; 1.1% for the sacral fracture group; and 1% for the iliac screw prominence group.

CONCLUSION

The aggregate rate of SPFF after ASD surgery is 22.1%. The most common mechanisms of failure were pseudarthrosis, rod fracture, and iliac screw loosening. Studies of SPFF remain heterogeneous, and a consistent definition of what constitutes SPFF is needed. This study may enable surgeons to provide patient specific constructs with pelvic fixation constructs to minimize this risk of failure.

Rod fractures in thoracolumbar fusions to the sacrum/pelvis for adult symptomatic lumbar scoliosis: long-term follow-up of a prospective, multicenter cohort of 160 patients

OBJECTIVE

Previous reports of rod fracture (RF) in adult spinal deformity are limited by heterogeneous cohorts, low follow-up rates, and relatively short follow-up durations. Since the majority of RFs present > 2 years after surgery, true occurrence and revision rates remain unclear. The objectives of this study were to better understand the risk factors for RF and assess its occurrence and revision rates following primary thoracolumbar fusions to the sacrum/pelvis for adult symptomatic lumbar scoliosis (ASLS) in a prospective series with long-term follow-up.

METHODS

Patient records were obtained from the Adult Symptomatic Lumbar Scoliosis-1 (ASLS-1) database, an NIH-sponsored multicenter, prospective study. Inclusion criteria were as follows: patients aged 40-80 years undergoing primary surgeries for ASLS (Cobb angle ≥ 30° and Oswestry Disability Index ≥ 20 or Scoliosis Research Society-22r ≤ 4.0 in pain, function, and/or self-image) with instrumented fusion of ≥ 7 levels that included the sacrum/pelvis. Patients with and without RF were compared to assess risk factors for RF and revision surgery.

RESULTS

Inclusion criteria were met by 160 patients (median age 62 years, IQR 55.7-67.9 years). At a median follow-up of 5.1 years (IQR 3.8-6.6 years), there were 92 RFs in 62 patients (38.8%). The median time to RF was 3.0 years (IQR 1.9-4.54 years), and 73% occurred > 2 years following surgery. Based on Kaplan-Meier analyses, estimated RF rates at 2, 4, 5, and 8 years after surgery were 11%, 24%, 35%, and 49%, respectively. Baseline radiographic, clinical, and demographic characteristics were similar between patients with and without RF. In Cox regression models, greater postoperative pelvic tilt (HR 1.895, 95% CI 1.196-3.002, p = 0.0065) and greater estimated blood loss (HR 1.02, 95% CI 1.005-1.036, p = 0.0088) were associated with increased risk of RF. Thirty-eight patients (61% of all RFs) underwent revision surgery. Bilateral RF was predictive of revision surgery (HR 3.52, 95% CI 1.8-6.9, p = 0.0002), while patients with unilateral nondisplaced RFs were less likely to require revision (HR 0.39, 95% CI 0.18-0.84, p = 0.016).

CONCLUSIONS

This study provides what is to the authors' knowledge the highest-quality data to date on RF rates following ASLS surgery. At a median follow-up of 5.1 years, 38.8% of patients had at least one RF. Estimated RF rates at 2, 4, 5, and 8 years after surgery were 11%, 24%, 35%, and 49%, respectively. Greater estimated blood loss and postoperative pelvic tilt were significant risk factors for RF. These findings emphasize the importance of long-term follow-up to realize the true prevalence and cumulative incidence of RF.

Is L5/S1 interbody fusion necessary in long-segment surgery for adult degenerative scoliosis? A systematic review and meta-analysis

OBJECTIVE

There is no consensus regarding the best surgical strategy at the lumbosacral junction (LSJ) in long constructs for adult spinal deformity (ASD). The use of interbody fusion (IF) has been advocated to increase fusion rates, with additional pelvic fixation (PF) typically recommended. The actual benefit of IF even when extending to the pelvis, however, has not been vigorously analyzed. The goal of this work was to better understand the role of IF, specifically with respect to arthrodesis, when extending long constructs to the ilium.

METHODS

A systematic review of the PubMed and Cochrane databases was performed to identify the relevant studies in English, addressing the management of LSJ in long constructs (defined as ≥ 5 levels) in ASD. The search terms used were as follows: "Lumbosacral Junction," "Long Constructs," "Long Fusion to the Sacrum," "Sacropelvic Fixation," "Interbody Fusion," and "Iliac Screw." The authors excluded technical notes, case reports, literature reviews, and cadaveric studies; pediatric populations; pathologies different from ASD; studies not using conventional techniques; and studies focused only on alignment of different levels.

RESULTS

The PRISMA protocol was used. The authors found 12 retrospective clinical studies with a total of 1216 patients who were sorted into 3 different categories: group 1, using PF or not (n = 6); group 2, using PF with or without IF (n = 5); and group 3, from 1 study comparing anterior lumbar interbody fusion versus transforaminal lumbar interbody fusion. Five studies in group 1 and 4 in group 2 had pseudarthrosis rate as primary outcome and were selected for a quantitative analysis. Forest plots were used to display the risk ratio, and funnel plots were used to look at the risk of publication bias. The summary risk ratios were 0.36 (0.23-0.57, p < 0.001) and 1.03 (0.54-1.96, p = 0.94) for the PF and IF, respectively; there is a protective effect of overall pseudarthrosis for using PF in long constructs for ASD surgeries, but not for using IF.

CONCLUSIONS

The long-held contention that L5/S1 IF is always advantageous in long-construct deformity surgery is not supported by the current literature. Based on the findings from this systematic review and meta-analysis, PF with or without additional L5/S1 interbody grafting demonstrates similar overall construct pseudarthrosis rates. The added risk and costs associated with IF, therefore, should be more closely considered on a case-by-case basis.