Use of vertebroplasty to prevent proximal junctional fractures in adult deformity surgery: a biomechanical cadaveric study

Proximal Junctional Kyphosis and Failure Prophylaxis Improves Cost Efficacy, While Maintaining Optimal Alignment, in Adult Spinal Deformity Surgery

BACKGROUND AND OBJECTIVES

To investigate the cost-effectiveness and impact of prophylactic techniques on the development of proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) in the context of postoperative alignment.

METHODS

Adult spinal deformity patients with fusion to pelvis and 2-year data were included. Patients receiving PJK prophylaxis (hook, tether, cement, minimally-invasive surgery approach) were compared to those who did not. These cohorts were further stratified into "Matched" and "Unmatched" groups based on achievement of age-adjusted alignment criteria. Costs were calculated using the Diagnosis-Related Group costs accounting for PJK prophylaxis, postoperative complications, outpatient health care encounters, revisions, and medical-related readmissions. Quality-adjusted life years were calculated using Short Form-36 converted to Short-Form Six-Dimension (SF-6D) and used an annual 3% discount rate. Multivariate analysis controlling for age, sex, levels fused, and baseline deformity severity assessed outcomes of developing PJK/PJF if matched and/or with use of PJK prophylaxis.

RESULTS

A total of 738 adult spinal deformity patients met inclusion criteria (age: 63.9 ± 9.9, body mass index: 28.5 ± 5.7, Charlson comorbidity index: 2.0 ± 1.7). Multivariate analysis revealed patients corrected to age-adjusted criteria postoperatively had lower rates of developing PJK or PJF (odds ratio [OR]: 0.4, [0.2-0.8]; P = .011) with the use of prophylaxis. Among those unmatched in T1 pelvic angle, pelvic incidence lumbar lordosis mismatch, and pelvic tilt, prophylaxis reduced the likelihood of developing PJK (OR: 0.5, [0.3-0.9]; P = .023) and PJF (OR: 0.1, [0.03-0.5]; P = .004). Analysis of covariance analysis revealed patients matched in age-adjusted alignment had better cost-utility at 2 years compared with those without prophylaxis ($361 539.25 vs $419 919.43; P < .001). Patients unmatched in age-adjusted criteria also generated better cost ($88 348.61 vs $101 318.07; P = .005) and cost-utility ($450 190.80 vs $564 108.86; P < .001) with use of prophylaxis.

CONCLUSION

Despite additional surgical cost, the optimization of radiographic realignment in conjunction with prophylaxis of the proximal junction appeared to be a more cost-effective strategy, primarily because of the minimization of reoperations secondary to mechanical failure. Even among those not achieving optimal alignment, junctional prophylactic measures were shown to improve cost efficiency.

Revision Strategy for Proximal Junctional Failure: Combined Effect of Proximal Extension and Focal Correction

Study designRetrospective review of a prospectively-collected multicenter database.ObjectivesThe objective of this study was to determine optimal strategies in terms of focal angular correction and length of proximal extension during revision for PJF.Methods134 patients requiring proximal extension for PJF were analyzed in this study. The correlation between amount of proximal junctional angle (PJA) reduction and recurrence of proximal junctional kyphosis (PJK) and/or PJF was investigated. Following stratification by the degree of PJK correction and the numbers of levels extended proximally, rates of radiographic PJK (PJA >28° & ΔPJA >22°), and recurrent surgery for PJF were reported.ResultsBefore revision, mean PJA was 27.6° ± 14.6°. Mean number of levels extended was 6.0 ± 3.3. Average PJA reduction was 18.8° ± 18.9°. A correlation between the degree of PJA reduction and rate of recurrent PJK was observed (r = -.222). Recurrent radiographic PJK (0%) and clinical PJF (4.5%) were rare in patients undergoing extension ≥8 levels, regardless of angular correction. Patients with small reductions (<5°) and small extensions (<4 levels) experienced moderate rates of recurrent PJK (19.1%) and PJF (9.5%). Patients with large reductions (>30°) and extensions <8 levels had the highest rate of recurrent PJK (31.8%) and PJF (16.0%).ConclusionWhile the degree of focal PJK correction must be determined by the treating surgeon based upon clinical goals, recurrent PJK may be minimized by limiting reduction to <30°. If larger PJA correction is required, more extensive proximal fusion constructs may mitigate recurrent PJK/PJF rates.

Ligamentous Augmentation to Prevent Proximal Junctional Kyphosis and Failure: A Biomechanical Cadaveric Study

STUDY DESIGN

Biomechanical cadaveric study (level V).

OBJECTIVE

To evaluate the effectiveness of polyethylene bands looped around the supra-adjacent spinous process (SP) or spinal lamina (SL) in providing strength to the cephalad unfused segment and reducing junctional stress.

BACKGROUND

Proximal junctional kyphosis (PJK) is a pathologic kyphotic deformity adjacent to posterior spinal instrumentation after fusion constructs. Recent studies demonstrate a mismatch in stiffness between the instrumented construct and nonfused adjacent levels to be a causative factor in the development of PJK and proximal junction failure. To our knowledge, no biomechanical studies have addressed the effect of different methods of polyethylene band placement at the proximal junction.

MATERIALS AND METHODS

Twelve fresh frozen cadavers were divided into 3 groups of 4: pedicle screw-based instrumentation from T10 to L5 ("control"), T10-L5 instrumentation with a polyethylene band to the T9 "SP," T10-L5 instrumentation with 2 polyethylene bands to the T9 "SL." Specimens were tested with an eccentric (10 mm anterior) load at 5 mm/min for 15 mm or until failure occurred. Failure was defined by the inflection point on the load versus deformation curves. Linear regression was utilized to evaluate the effect of augmentation on the load-to-failure. Significance was set at 0.05.

RESULTS

Fractures occurred in all specimens tested. The mean peak load to failure was 2148 N (974-3322) for the SP group, and 1248 N (742-1754) for the control group ( P > 0.05) and 1390 N (1080-2004) for the SL group. No difference existed between the control group and the SP group in terms of fracture level ( P > 0.05). Net kyphotic angulation shows no differences among these 3 groups ( P > 0.05).

CONCLUSION

Although statistical significance was not achieved, ligament augmentation to the SP increased mean peak load-to-failure in a cadaveric PJK model.

Is ABO blood type a risk factor for adjacent segment degeneration after lumbar spine fusion?

PURPOSE

This study aimed to explore associations between ABO blood type and postoperative adjacent segment degeneration/disease (ASD) following lumbar spine fusion, as well as evaluate differences in spinopelvic alignment, perioperative care, postoperative complications, and patient-reported outcome measures (PROMs).

METHODS

An ambispective study was performed. Patients who underwent posterolateral or posterior lumbar interbody fusion were included. Demographic, perioperative and postoperative, clinical, and blood type information was recorded. Pre- and post-operative radiographic imaging was analyzed for alignment parameters and development of ASD.

RESULTS

445 patients were included, representing O+ (36.0%), O- (5.2%), A+ (36.2%), A- (6.3%), B+ (12.1%), B- (1.6%), and AB+ (2.7%) blood types. Most patients were female (59.1%), and had a mean age of 60.3 years and BMI of 31.1 kg/m2. Postoperatively, groups did not differ in duration of the hospital (p = 0.732) or intensive care unit (p = 0.830) stay, discharge disposition (p = 0.504), reoperation rate (p = 0.192), or in-hospital complication rate (p = 0.377). Postoperative epidural hematoma was most common amongst A + patients (p = 0.024). Over a mean of 11.0 months of follow-up, all patients exhibited similar improvement in PROMs, with 132 (29.7%) patients developing radiographic evidence of ASD. B + patients were significantly more likely than A + and O + patients to develop spondylolisthesis and ASD (p < 0.05). No significant differences in sagittal alignment parameters and number of levels of fusion were found (p > 0.05).

CONCLUSIONS

This is the first large-scale study to address and demonstrate proof-of-principle that ABO blood type, a non-modifiable risk factor, is associated with ASD following lumbar spine fusion.

Surgical Management of Adult Spinal Deformity Patients with Osteoporosis

Adult spinal deformity (ASD) commonly affects older adults, with up to 68% prevalence in those over 60, and is often complicated by osteoporosis, which reduces bone mineral density (BMD) and increases surgical risks. Osteoporotic patients undergoing ASD surgery face higher risks of complications like hardware failure, pseudoarthrosis, and proximal junctional kyphosis (PJK). Medical management with antiresorptive medications (e.g., bisphosphonates, SERMs, and denosumab) and anabolic agents (e.g., teriparatide, abaloparatide, and romosozumab) can improve BMD and reduce complications. While bisphosphonates reduce fracture risk, teriparatide and newer agents like romosozumab show promise in increasing bone density and improving fusion rates. Surgical adaptations such as consideration of age-adjusted alignment, fusion level selection, cement augmentation, and the use of expandable screws or tethers enhance surgical outcomes in osteoporotic patients. Specifically, expandable screws and cement augmentation have been shown to improve fixation stability. However, further research is needed to evaluate the effectiveness of these treatments, specifically in osteoporotic ASD patients.

Spinal alignment and surgical correction in the aging spine and osteoporotic patient

Background

The aging spine often presents multifaceted surgical challenges for the surgeon because it can directly and indirectly impact a patient's spinal alignment and quality of life. Elderly and osteoporotic patients are predisposed to progressive spinal deformities and potential neurologic compromise and surgical management can be difficult because these patients often present with greater frailty.

Methods

This was a literature review of spinal alignment changes, preoperative considerations, and spinal alignment considerations for surgical strategies.

Results

Many factors impact spinal alignment as we age including lumbar lordosis flexibility, hip flexion, deformity, and osteoporosis. Preoperative considerations are required to assess the patient's overall health, bone mineral density, and osteoporosis medications. Careful radiographic assessment of the spinopelvic parameters using various classification/scoring systems provide the surgeon with goals for surgical treatment. An individualized surgical strategy can be planned for the patient including extent of surgery, surgical approach, extent of the constructs, fixation techniques, vertebral augmentation, ligamentous augmentation, and staging surgery.

Conclusions

Surgical treatment should only be considered after a thorough assessment of the patient's health, deformity, bone quality and corresponding age matched alignment goals. An individualized treatment approach is often required to tackle the deformity and minimize the risk of hardware related complications and pseudarthrosis. Anabolic agents offer a promising benefit in this patient population by directly addressing and improving their bone quality and mineral density preoperatively and postoperatively.

Instrumentation Failure in Adult Spinal Deformity Patients

In recent years, advances in the surgical treatment of adult spinal deformity (ASD) have led to improved outcomes. Although these advances have helped drive the development of deformity surgery to meet the rising volume of patients seeking surgical treatment, many challenges have yet to be solved. Instrumentation failure remains one of the most common major complications following deformity surgery, associated with significant morbidity due to elevated re-operation rates among those experiencing mechanical complications. The two most frequently encountered subtypes of instrumentation failure are rod fracture (RF) and proximal junctional kyphosis/proximal junctional failure (PJK/PJF). While RF and PJK/PJF are both modes of instrumentation failure, they are two distinct entities with different clinical implications and treatment strategies. Considering that RF and PJK/PJF continue to represent a major challenge for patients with ASD and deformity surgeons alike, this review aims to discuss the incidence, risk factors, clinical impact, treatment strategies, preventive measures, and future research directions for each of these substantial complications.

Can We Rely on Prophylactic Two-Level Vertebral Cement Augmentation in Long-Segment Adult Spinal Deformity Surgery to Reduce the Incidence of Proximal Junctional Complications?

Background and Objectives: Proximal junctional kyphosis (PJK) and failure (PJF), the most prevalent complications following long-segment thoracolumbar fusions for adult spinal deformity (ASD), remain lacking in defined preventive measures. We studied whether one of the previously reported strategies with successful results-a prophylactic augmentation of the uppermost instrumented vertebra (UIV) and supra-adjacent vertebra to the UIV (UIV + 1) with polymethylmethacrylate (PMMA)-could also serve as a preventive measure of PJK/PJF in minimally invasive surgery (MIS). Materials and Methods: The study included 29 ASD patients who underwent a combination of minimally invasive lateral lumbar interbody fusion (MIS-LLIF) at L1-2 through L4-5, all-pedicle-screw instrumentation from the lower thoracic spine to the sacrum, S2-alar-iliac fixation, and two-level balloon-assisted PMMA vertebroplasty at the UIV and UIV + 1. Results: With a minimum 3-year follow-up, non-PJK/PJF group accounted for fifteen patients (52%), PJK for eight patients (28%), and PJF requiring surgical revision for six patients (21%). We had a total of seven patients with proximal junctional fracture, even though no patients showed implant/bone interface failure with screw pullout, probably through the effect of PMMA. In contrast to the PJK cohort, six PJF patients all had varying degrees of neurologic deficits from modified Frankel grade C to D3, which recovered to grades D3 and to grade D2 in three patients each, after a revision operation of proximal extension of instrumented fusion with or without neural decompression. None of the possible demographic and radiologic risk factors showed statistical differences between the non-PJK/PJF, PJK, and PJF groups. Conclusions: Compared with the traditional open surgical approach used in the previous studies with a positive result for the prophylactic two-level cement augmentation, the MIS procedures with substantial benefits to patients in terms of less access-related morbidity and less blood loss also provide a greater segmental stability, which, however, may have a negative effect on the development of PJK/PJF.

Three-column osteotomy in long constructs has lower rates of proximal junctional kyphosis and better restoration of lumbar lordosis than anterior column realignment

PURPOSE

Three-column osteotomies (TCOs) and minimally invasive techniques such as anterior column realignment (ACR) are powerful tools used to restore lumbar lordosis and sagittal alignment. We aimed to appraise the differences in construct and global spinal stability between TCOs and ACRs in long constructs.

METHODS

We identified consecutive patients who underwent a long construct lumbar or thoracolumbar fusion between January 2016 and November 2021. "Long construct" was any construct where the uppermost instrumented vertebra (UIV) was L2 or higher and the lowermost instrumented vertebra (LIV) was in the sacrum or ileum.

RESULTS

We identified 69 patients; 14 (20.3%) developed PJK throughout follow-up (mean 838 days). Female patients were less likely to suffer PJK (p = 0.009). TCO was more associated with open (versus minimally invasive) screw/rod placement, greater number of levels, higher UIV, greater rate of instrumentation to the ilium, and posterior (versus anterior) L5-S1 interbody placement versus the ACR cohort (p < 0.001, p < 0.001, p < 0.001, p < 0.001, p = 0.005, respectively). Patients who developed PJK were more likely to have undergone ACR (12 (32.4%) versus 2 (6.3%, p = 0.007)). The TCO cohort had better improvement of lumbar lordosis despite similar preoperative measurements (ACR: 16.8 ± 3.78°, TCO: 23.0 ± 5.02°, p = 0.046). Pelvic incidence-lumbar lordosis mismatch had greater improvement after TCO (ACR: 14.8 ± 4.02°, TCO: 21.5 ± 5.10°, p = 0.042). By multivariate analysis, ACR increased odds of PJK by 6.1-times (95% confidence interval: 1.20-31.2, p = 0.29).

CONCLUSION

In patients with long constructs who undergo ACR or TCO, we experienced a 20% rate of PJK. TCO decreased PJK 6.1-times compared to ACR. TCO demonstrated greater improvement of some spinopelvic parameters.

Polymethyl methacrylate augmentation and proximal junctional kyphosis in adult spinal deformity patients

BACKGROUND

Proximal junctional kyphosis (PJK) is a complication following surgery for adult spinal deformity (ASD) possibly ameliorated by polymethyl methacrylate (PMMA) vertebroplasty of the upper instrumented vertebrae (UIV). This study quantifies PJK following surgical correction bridging the thoracolumbar junction ± PMMA vertebroplasty.

METHODS

ASD patients from 2013 to 2020 were retrospectively reviewed and included with immediate postoperative radiographs and at least one follow-up radiograph. PMMA vertebroplasty at the UIV and UIV + 1 was performed at the surgeons' discretion.

RESULTS

Of 102 patients, 56% received PMMA. PMMA patients were older (70 ± 8 vs. 66 ± 10, p = 0.021), more often female (89.3% vs. 68.2%, p = 0.005), and had more osteoporosis (26.8% vs. 9.1%, p = 0.013). 55.4% of PMMA patients developed PJK compared to 38.6% of controls (p = 0.097), and the rate of PJK development was not different between groups in univariate survival models. There was no difference in PJF (p > 0.084). Reoperation rates were 7.1% in PMMA versus 11.4% in controls (p = 0.501). In multivariable models, PJK development was not associated with the use of PMMA vertebroplasty (HR 0.77, 95% CI 0.38-1.60, p = 0.470), either when considered overall in the cohort or specifically in those with poor bone quality. PJK was significantly predicted by poor bone quality irrespective of PMMA use (HR 3.81, p < 0.001).

CONCLUSIONS

In thoracolumbar fusions for adult spinal deformity, PMMA vertebroplasty was not associated with reduced PJK development, which was most highly associated with poor bone quality. Preoperative screening and management for osteoporosis is critical in achieving an optimal outcome for these complex operations.

LEVEL OF EVIDENCE

4, retrospective non-randomized case review.

Navigated Hybrid Open/Muscle-sparing Approach to 2-level Cement Augmentation of the UIV and UIV+1 for Prevention of Proximal Junctional Failure: Supplemental Manuscript to Operative Video

STUDY DESIGN

Operative video and supplemental manuscript.

OBJECTIVE

To present a cement augmentation technique of the upper instrumented vertebra (UIV) and UIV+1 for prevention of proximal junctional fractures (PJFs) in multi-level thoracolumbar posterior instrumented fusions.

SUMMARY OF BACKGROUND DATA

PJFs are unfortunately a common occurrence after multi-level thoracolumbar instrumented fusions to the pelvis for adult spinal deformity that can result in significant functional disability and often require costly revision operations. As such, their prevention is key.

METHODS

A surgical video illustrates the nuances of a 2-level cement augmentation technique, consisting of an open vertebroplasty of the UIV through fenestrated screws and a muscle-sparing kyphoplasty of the UIV+1.

RESULTS

Utility of performing an open vertebroplasty of the UIV through fenestrated screws and muscle-sparing kyphoplasty of the UIV+1 lies in its ability to minimize soft-tissue disruption at the adjacent segment while providing additional structural support to the anterior column at this high-risk zone.

CONCLUSIONS

Cement augmentation of the UIV and UIV+1 consisting of a hybrid open vertebroplasty and muscle-sparing kyphoplasty can be an effective strategy to decrease the incidence of PJF after multi-level posterior thoracolumbar instrumented fusions to the pelvis for adult spinal deformity.

Advances and Evolving Challenges in Spinal Deformity Surgery

BACKGROUND

Surgical intervention is a critical tool to address adult spinal deformity (ASD). Given the evolution of spinal surgical techniques, we sought to characterize developments in ASD correction and barriers impacting clinical outcomes.

METHODS

We conducted a literature review utilizing PubMed, Embase, Web of Science, and Google Scholar to examine advances in ASD surgical correction and ongoing challenges from patient and clinician perspectives. ASD procedures were examined across pre-, intra-, and post-operative phases.

RESULTS

Several factors influence the effectiveness of ASD correction. Standardized radiographic parameters and three-dimensional modeling have been used to guide operative planning. Complex minimally invasive procedures, targeted corrections, and staged procedures can tailor surgical approaches while minimizing operative time. Further, improvements in osteotomy technique, intraoperative navigation, and enhanced hardware have increased patient safety. However, challenges remain. Variability in patient selection and deformity undercorrection have resulted in heterogenous clinical responses. Surgical complications, including blood loss, infection, hardware failure, proximal junction kyphosis/failure, and pseudarthroses, pose barriers. Although minimally invasive approaches are being utilized more often, clinical validation is needed.

CONCLUSIONS

The growing prevalence of ASD requires surgical solutions that can lead to sustained symptom resolution. Leveraging computational and imaging advances will be necessary as we seek to provide comprehensive treatment plans for patients.

Proximal Junctional Kyphosis and Failure: Strategies for Prevention

Proximal junctional kyphosis (PJK) and proximal junctional failure/fractures (PJF) are common complications following long-segment posterior instrumented fusions for adult spinal deformity. As progression to PJF involves clinical consequences for patients and requires costly revisions that may undermine the utility of surgery and are ultimately unsustainable for health care systems, preventative strategies to minimize the occurrence of PJF are of tremendous importance. In this article, the authors present a detailed outline of PJK and PJF with a focus on surgical strategies aimed at preventing their occurrence..

Percutaneous Vertebroplasty and Upper Instrumented Vertebra Cement Augmentation Reducing Early Proximal Junctional Kyphosis and Failure Rate in Adult Spinal Deformity: Case Series and Literature Review

BACKGROUND AND OBJECTIVES

One of the risks involved after long-segment fusions includes proximal junctional kyphosis (PJK) and proximal junctional failure (PJF). There are reported modalities to help prevent this, including 2-level prophylactic vertebroplasty. In this study, our goal was to report the largest series of prophylactic cement augmentation with upper instrumented vertebra (UIV) + 1 vertebroplasty and a literature review.

METHODS

We retrospectively reviewed our long-segment fusions for adult spinal deformity from 2018 to 2022. The primary outcome measures included the incidence of PJK and PJF. Secondary outcomes included preoperative and postoperative Oswestry Disability Index, visual analog scale back and leg scores, surgical site infection, and plastic surgery closure assistance. In addition, we performed a literature review searching PubMed with a combination of the following words: "cement augmentation," "UIV + 1 vertebroplasty," "adjacent segment disease," and "prophylactic vertebroplasty." We found a total of 8 articles including 4 retrospective reviews, 2 prospective reviews, and 2 systematic reviews. The largest cohort of these articles included 39 patients with a PJK/PJF incidence of 28%/5%.

RESULTS

Overall, we found 72 long-segment thoracolumbar fusion cases with prophylactic UIV cement augmentation with UIV + 1 vertebroplasty. The mean follow-up time was 17.25 months. Of these cases, 8 (11.1%) developed radiographic PJK and 3 (4.2%) required reoperation for PJF. Of the remaining 5 patients with radiographic PJK, 3 were clinically asymptomatic and treated conservatively and 2 had distal fractured rods that required only rod replacement.

CONCLUSION

In this study, we report the largest series of patients with prophylactic percutaneous vertebroplasty and UIV cement augmentation with a low PJK and PJF incidence of 11.1% and 4.2%, respectively, compared with previously reported literature. Surgeons who regularly perform long-segment fusions for adult spinal deformity can consider this in their armamentarium when using methods to prevent adjacent segment disease because it is an effective modality in reducing early PJK and PJF that can often result in revision surgery.

Vertebral Bone Quality Score Independently Predicts Proximal Junctional Kyphosis and/or Failure After Adult Spinal Deformity Surgery

BACKGROUND

Proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) can be catastrophic complications associated with adult spinal deformity (ASD) surgery. These complications are markedly influenced by osteoporosis, leading to additional vertebral fracture and pedicle screw loosening. The MRI-based vertebral bone quality score (VBQ) is a newly developed tool that can be used to assess bone quality.

OBJECTIVE

To investigate the utility of the VBQ score in predicting PJK and/or PJF (PJF/PJK) after ASD correction.

METHODS

We conducted a retrospective chart review to identify patients age ≥50 years who had received ASD surgery of 5 or more thoracolumbar levels. Demographic, spinopelvic parameters, and procedure-related variables were collected. Each patient's VBQ score was calculated using preoperative T1-weighted MRI. Univariate analysis and multivariate logistic regression were performed to determine potential risk factors of PJK/PJF. Receiver operating characteristic analysis and area-under-the-curve values were generated for prediction of PJK/PJF.

RESULTS

A total of 116 patients were included (mean age, 64.1 ± 6.8 years). Among them, 34 patients (29.3%) developed PJK/PJF. Mean VBQ scores were 3.13 ± 0.46 for patients with PJK/PJF and 2.46 ± 0.49 for patients without, which was significantly different between the 2 groups ( P < .001). On multivariate analysis, VBQ score was the only significant predictor of PJK/PJF (odds ratio = 1.745, 95% CI = 1.558-1.953, P < .001), with a predictive accuracy of 94.3%.

CONCLUSION

In patients undergoing ASD correction, higher VBQ was independently associated with PJK/PJF occurrence. Measurement of VBQ score on preoperative MRI may be a useful adjunct to ASD surgery planning.

The efficacy of prophylactic vertebroplasty for preventing proximal junctional complications after spinal fusion: a systematic review

BACKGROUND CONTEXT

Prophylactic vertebroplasty (VP) is performed at the upper level of instrumentation during spinal fusion to reduce the risk of proximal junctional kyphosis (PJK), proximal junctional fracture (PJFx), and proximal junctional failure (PJF). This study investigated the effect of VP on patient outcomes after spinal fusion.

PURPOSE

The aim of this systematic review was to evaluate the effect of prophylactic VP on the incidence of PJK in patients with spinal fusion.

STUDY DESIGN/SETTING

Level III, systematic review without meta-analysis.

PATIENT SAMPLE

Adult patients undergoing spinal fusion with VP.

METHODS

A PRISMA-compliant systematic literature review was conducted using PubMed/MEDLINE, Cochrane, and Embase. Included studies were published in English between January 1, 2001, and May 27, 2021, and reported primary data on adult patients undergoing spinal fusion with VP. Studies were excluded for insufficient surgical details; treatment for vertebral compression fracture; and case series and/or reports with <5 patients. The Newcastle-Ottawa Scale was used to assess risk of bias. The primary outcome of interest was PJK. Other outcomes included PJFx, PJF, and adverse events (eg, cement extravasation). Data were expressed as descriptive statistics.

RESULTS

Eight studies with 685 total patients (VP: 293 [42.8%]; No VP: 392 (57.2%)) were included. Five studies were comparative and three were single-arm. PJK incidence was reported in five studies (three comparatives, two single-arm) and ranged from 7.9% to 46.4%; incidence was lower in patients with VP in two of three (66.7%) comparative studies, and equal in one of three (33.3%). PJFx was reported in five studies (four comparatives, one single-arm) and ranged from 0.0% to 39.3%; incidence was lower in the VP group in two of four (50.0%) comparative studies, equal in one of four (25.0%), and higher in one of four (25.0%). PJF was reported in five studies (three comparatives, two single-arm) and ranged from 0.0% to 39.3%; incidence was lower in the VP group in two of three (66.7%) comparative studies and equal in one of three (33.3%). Cement extravasation was reported by four studies and ranged from 0% (0/36) to 48.3% (57/118) in patients with prophylactic VP.

CONCLUSIONS

Evidence on whether prophylactic VP decreases the incidence of PJK, PJFx, and PJF after spinal fusion is inconclusive and conflicting. Additionally, the risk of cement extravasation following prophylactic VP could not be evaluated due to insufficient evidence. Further research is needed to determine whether VP has a significant impact on patient outcomes and risks.

Failure in Adult Spinal Deformity Surgery: A Comprehensive Review of Current Rates, Mechanisms, and Prevention Strategies

STUDY DESIGN

Literature review.

OBJECTIVE

The aim of this review is to summarize recent literature on adult spinal deformity (ASD) treatment failure as well as prevention strategies for these failure modes.

SUMMARY OF BACKGROUND DATA

There is substantial evidence that ASD surgery can provide significant clinical benefits to patients. The volume of ASD surgery is increasing, and significantly more complex procedures are being performed, especially in the aging population with multiple comorbidities. Although there is potential for significant improvements in pain and disability with ASD surgery, these procedures continue to be associated with major complications and even outright failure.

METHODS

A systematic search of the PubMed database was performed for articles relevant to failure after ASD surgery. Institutional review board approval was not needed.

RESULTS

Failure and the potential need for revision surgery generally fall into 1 of 4 well-defined phenotypes: clinical failure, radiographic failure, the need for reoperation, and lack of cost-effectiveness. Revision surgery rates remain relatively high, challenging the overall cost-effectiveness of these procedures.

CONCLUSION

By consolidating the key evidence regarding failure, further research and innovation may be stimulated with the goal of significantly improving the safety and cost-effectiveness of ASD surgery.

CT based bone mineral density as a predictor of proximal junctional fractures

Background

Proximal junctional fractures (PJFr) can be a catastrophic complication associated with adult spinal deformity surgery. Osteoporosis can be a major risk factor for the cause of PJFr. Recent studies suggest using surrogate computed tomography (CT) scans in place of spinal dual-energy x-ray absorptiometry (DEXA) scores for bone mineral density (BMD). Investigate the feasibility of using preoperative CT based bone mineral density at upper instrumented vertebrae (UIV) and one level proximally (UIV+1) and distally (UIV-1) to predict the possibility of PJFr risk.

Methods

Retrospective two-academic center case-controlled study, reviewed consecutive adult spinal deformity surgeries; included constructs encompassing at least five fusion levels and fusions to pelvis. Examined demographic, surgical, and radiographic data preoperatively, postoperatively, and final follow-up. Formed groups based on type of proximal junctional deformity (PJD): Control (no PJD), proximal junctional kyphosis (PJK) and PJFr. Preoperative CT BMD values measured in Hounsfield units (HU) for sagittal and axial planes at UIV, UIV+1, and UIV-1 and compared between groups.

Results

N=92 patients. Preoperative CT scan BMD values were significantly lower in PJFr vs. control at: UIV+1 in sagittal (p=0.007), axial (p=0.02) planes; UIV sagittal (p=0.04) and axial (p=0.03) planes; and UIV-1 sagittal (p=0.05) plane. Similarly, lower CT scan BMD values noted in PJFr vs. PJK at: UIV+1 in sagittal (p=0.04) and axial (p=0.03) planes. Trend seen with lower CT scan BMD values at UIV+1 level in PJFr vs. PJK in sagittal (p=0.12) and axial (p=0.10) planes. Preoperative global sagittal imbalance measurements significantly lower in control, but comparable between PJK and PJFr.

Conclusions

Higher preoperative global sagittal imbalance with lower preoperative CT BMD values at UIV and UIV+1 vertebral body may increase the risk of proximal junctional fractures after adult spine deformity surgery. Proximal junctional hooks may supplement the pathogenesis. Readers should note the small sample size.

Level of Evidence: 3

Instrumentation Techniques to Prevent Proximal Junctional Kyphosis and Proximal Junctional Failure in Adult Spinal Deformity Correction: A Systematic Review of Clinical Studies

STUDY DESIGN

Systematic review.

OBJECTIVES

To summarize the results of clinical studies investigating spinal instrumentation techniques aiming to reduce the postoperative incidence of proximal junctional kyphosis (PJK) and/or failure (PJF) in adult spinal deformity (ASD) patients.

METHODS

EMBASE and Medline® were searched for articles dating from January 2000 onward. Data was extracted by 2 independent authors and methodological quality was assessed using ROBINS-I.

RESULTS

18 retrospective- and prospective cohort studies with a severe or critical risk of bias were included. Different techniques were applied at the upper instrumented vertebra (UIV): tethers in various configurations, 2-level prophylactic vertebroplasty (2-PVP), transverse process hooks (TPH), flexible rods (FR), sublaminar tapes (ST) and multilevel stabilization screws (MLSS). Compared to a pedicle screw (PS) group, significant differences in PJK incidence were found using tethers in various configurations (18% versus 45%, P = 0.001, 15% versus 38%, P = 0.045), 2-PVP (24% vs 36%, P = 0.020), TPH (0% vs. 30%, P = 0.023) and FR (15% versus 38%, P = 0.045). Differences in revision rates for PJK were found in studies concerning tethers (4% versus 18%, P = 0.002), 2-PVP (0% vs 13%, P = 0.031) and TPH (0% vs 7%, P = n.a.).

CONCLUSION

Although the studies are of low quality, the most frequently studied techniques, namely 2-PVP as anterior reinforcement and (tensioned) tethers or TPH as posterior semi-rigid fixation, show promising results. To provide a reliable comparison, more controlled studies need to be performed, including the use of clinical outcome measures and a uniform definition of PJF.

Decompression and fusion surgery for osteoporotic vertebral fractures: WFNS Spine Committee Recommendations

INTODUCTION

Osteoporotic vertebral fractures (OVF) are common due to aging populations. Their clinical management remains controversial. Although conservative approaches are sufficient in most cases, there are certain conditions where decompression or fusion surgery are necessary. This manuscript aims to clarify the indications and types of surgeries for OVF.

EVIDENCE ACQUISITION

A Medline and Pubmed search spanning the period between 2010 and 2020 was performed using the keywords "osteoporotic vertebral fractures and decompression surgery" and "osteoporotic vertebral fractures and fusion surgery". In addition, we reviewed up-to-date information on decompression and fusion in osteoporotic vertebral fracture (OVF) to reach an agreement in two consensus meetings of the World Federation of Neurosurgical Societies (WFNS) Spine Committee that was held in January and February 2021. The Delphi method was utilized to improve the validity of the questionnaire.

EVIDENCE SYNTHESIS

A total of 19 studies examining decompression and fusion surgery in OVF were reviewed. Literature supports the statement that decompression and fusion surgery are necessary for progressive neurological deficits after OVF. The Spine Section of the German Society for Orthopedics and Trauma (DGOU) classification revealed that it might help make surgical decisions. We also noted that in patients planning to undergo surgery to correct significant kyphosis after OVF, several techniques, including multilevel fixation, cement augmentation, preservation of sagittal balance, and avoiding termination at the apex of kyphosis are necessary to prevent complications. Additionally, it became clear that there is no consensus to choose the type of open surgery (anterior, posterior, combined, using cement or bone or vertebral body cage, the levels, and kind of instrumentation). The current literature indicated that implant failure in the osteoporotic spine is a common complication, and many techniques have been described to prevent implant failure in the osteoporotic spine. However, the superiority of one method over another is unclear.

CONCLUSIONS

Open surgery for osteoporotic vertebral fractures should be considered if neurologic deficits and significant painful kyphosis. The apparent indications of surgery and most ideal surgical technique for OVF remain unclear in the literature; therefore, the decision must be individualized.

Effect of overcorrection on proximal junctional kyphosis in adult spinal deformity: analysis by age-adjusted ideal sagittal alignment

BACKGROUND CONTEXT

The effect of the degree of lumbar lordosis (LL) correction on proximal junctional kyphosis (PJK) has not been analyzed in context of the age-adjusted sagittal alignment goal.

PURPOSE

To determine the effect of sagittal correction on the incidence of PJK after an age-adjusted analysis in patients with adult spinal deformity (ASD).

STUDY DESIGN/SETTING

Retrospective comparative study.

PATIENT SAMPLE

Seventy-eight ASD patients who underwent deformity correction.

OUTCOME MEASURES

Visual analog scale (VAS), Oswestry Disability Index (ODI), and imaging.

METHODS

This study included 78 ASD patients who underwent deformity correction and were followed-up more than 2 years. Patients were grouped according to the degree of LL correction relative to pelvic incidence (PI) by adjusting for age using the following formula: (age-adjusted ideal PI - LL) - (postoperative PI - LL). These were group U (undercorrection; <-10˚, N=15), group I (ideal correction; -10˚-10˚, N=34), and group O (over correction, >10˚, N=29). Various clinical and radiological parameters were compared among groups. The risk factors for PJK were also evaluated.

RESULTS

The overall incidence of PJK was 32.1% (25/78), with significantly higher PJK rate in group O (48.3%) compared with groups U (13.3%) and I (26.5%) (p=.041). The degree of postoperative LL correction relative to the PI by adjusting for age was a risk factor for the development of PJK (11.4° for PJK vs. 0.2° for non-PJK, p=.033). In addition, 2-year postoperative VAS (7.0 vs. 3.4, p<.001) and ODI (28.9 vs. 24.8, p=.040) scores were significantly higher in the PJK group than in the non-PJK group. A small PI (PI < 45°) was associated with a tendency of overcorrection (73.3%, P < 0.001) and thereby with the high incidence of PJK (53.3%, p=.005).

CONCLUSIONS

Overcorrection of LL relative to PI considering age-adjusted ideal sagittal alignment tends to increase the incidence of PJK. The incidence of PJK is expected to be high in patients with low PI (<45°) because of the tendency of overcorrection. To reduce the risk of PJK, surgeons should take age-adjusted parameters into account and exercise caution not to overcorrect patients with low PI, since this can result in suboptimal clinical outcomes.

Postoperative and Intraoperative Cement Augmentation for Spinal Fusion

OBJECTIVE

To review outcomes of patients undergoing spinal fusion with prophylactic cement augmentation (CA) of pedicle screws and adjacent levels.

METHODS

In a retrospective case-control study, 59 patients underwent CA of pedicle screws for spinal fusion between 2003 and 2018. Most patients (83%) underwent postoperative CA, while 17% underwent intraoperative CA. Outcomes of CA techniques were compared, and patients undergoing CA for a thoracolumbar fusion (n = 51) were compared with a cohort not undergoing CA (n = 39). Mean follow-up was 3 years.

RESULTS

In patients receiving CA, survivorship free of proximal junctional kyphosis (PJK) was 94%, 60%, and 20% at 2, 5, and 10 years postoperatively. Survivorship free of revision was 95%, 83%, and 83% at 2, 5, and 10 years postoperatively. Development of PJK (P = 0.02, odds ratio [OR] 24.44) was associated with revision surgery. There were 4 (7%) cardiopulmonary complications. Patients who received CA for thoracolumbar fusion were older (70 years vs. 65 years) and were more likely to have osteoporosis (53% vs. 5%) than patients who did not receive CA. CA was associated with a decreased risk of PJK (P = 0.009, OR 0.16), while osteoporosis (P = 0.05, OR 4.10) and fusion length ≥8 levels (P = 0.06, OR 2.65) were associated with PJK. PJK was associated with revision surgery (P = 0.006, OR 12.65).

CONCLUSIONS

CA allows for substantial rates of radiographic PJK; however, this typically does not result in a need for revision surgery and leads to revision and PJK rates that are comparable to patients undergoing long segment fusions without osteoporosis.

Mechanical Complications in Adult Spinal Deformity Surgery: Can Spinal Alignment Explain Everything?

STUDY DESIGN

Cohort study.

OBJECTIVE

Our goal was to verify the validity of the global alignment and proportion (GAP) score, SRS-Schwab, and Roussouly theoretical apex of lordosis in predicting mechanical complications in adult spinal deformity (ASD).

SUMMARY OF BACKGROUND DATA

Achieving adequate sagittal alignment is critical to obtain favorable outcomes in ASD surgery. It has been proposed that mechanical complications are largely secondary to postoperative spinal alignment.

METHODS

Retrospective review of consecutive primary ASD cases that underwent deformity correction in the same institution over a 5-year period. Association between the 6-week postoperative spinal alignment classification and occurrence of mechanical complications on the last follow-up was assessed using logistic regressions. The discriminant capacity was assessed using the receiver operating characteristic (ROC) curve analysis.

RESULTS

58.3% (N = 49/84) of patients presented with mechanical complications and 32.1% (N = 27/84) underwent revision surgery. GAP score did not show discriminant ability to predict complications (AUC = 0.53, 95% confidence interval [CI] = 0.40-0.66, P = 0.58). Conversely, the SRS-Schwab sagittal modifier score demonstrated a statistically significant (although modest) predictive value for mechanical complications (AUC = 0.67, 95% CI = 0.54-0.79, P = 0.008). There was a significant association between pelvic tilt (PT) (P = 0.03) and sagittal vertical axis (SVA) (P = 0.01) at 6 weeks postoperatively and the occurrence of later mechanical complications. There was no significant association between matched Roussouly theoretical apex of lordosis and final outcome (P = 0.47).

CONCLUSION

The results point to the complexity of mechanical failure and the high likelihood that causative factors are multifactorial and not limited to alignment measures. GAP score should be used with caution as it may not explain or predict mechanical failure based on alignment in all populations as originally expected. Future studies should focus on etiology, surgical technique, and patient factors in order to generate a more universal score that can be applied to all populations.Level of Evidence: 4.

Restricted cement augmentation in unstable geriatric midthoracic fractures treated by long-segmental posterior stabilization leads to a comparable construct stability

The goal of this study is to compare the construct stability of long segmental dorsal stabilization in unstable midthoracic osteoporotic fractures with complete pedicle screw cement augmentation (ComPSCA) versus restricted pedicle screw cement augmentation (ResPSCA) of the most cranial and caudal pedicle screws under cyclic loading. Twelve fresh frozen human cadaveric specimens (Th4–Th10) from individuals aged 65 years and older were tested in a biomechanical cadaver study. All specimens received a DEXA scan and computer tomography (CT) scan prior to testing. All specimens were matched into pairs. These pairs were randomized into the ComPSCA group and ResPSCA group. An unstable Th7 fracture was simulated. Periodic bending in flexion direction with a torque of 2.5 Nm and 25,000 cycles was applied. Markers were applied to the vertebral bodies to measure segmental movement. After testing, a CT scan of all specimens was performed. The mean age of the specimens was 87.8 years (range 74–101). The mean T-score was − 3.6 (range − 1.2 to − 5.3). Implant failure was visible in three specimens, two of the ComPSCA group and one of the ResPSCA group, affecting only one pedicle screw in each case. Slightly higher segmental movement could be evaluated in these three specimens. No further statistically significant differences were observed between the study groups. The construct stability under cyclic loading in flexion direction of long segmental posterior stabilization of an unstable osteoporotic midthoracic fracture using ResPSCA seems to be comparable to ComPSCA.

Novel Distributed Loading Technique Using Multimaterial, Long-Segment Spinal Constructs to Prevent Proximal Junctional Pathology in Adult Spinal Deformity Correction-Operative Technique and Radiographic Findings

BACKGROUND

Proximal junctional kyphosis (PJK) and proximal junction failure are common and costly complications after long-segment adult spinal deformity (ASD) correction. Although much research has focused on the concept of "softening the landing" to prevent proximal junction pathologies, long-segment constructs largely deviate from the force-deformation curve of the physiologic spine. Our novel distributed loading technique for ASD correction is described using multimaterial, long-segment constructs to create a biomechanically sound, yet physiologic, decremental stiffness toward the rostral end.

METHODS

Operative steps detail the custom-designed constructs of dual-headed pedicle screws and varied rod diameters and materials (cobalt chromium or titanium) for an initial 20 patients (mean 66.6 ± 4.8 years). Standing scoliosis films were obtained preoperatively and at regular intervals postoperatively to assess for PJK.

RESULTS

No patient had evidence of PJK or proximal junction failure at latest radiographic follow-up (mean 17.9 months, range 13-25 months). Radiographic findings for sagittal vertical axis averaged 11.2 ± 5.6 cm preoperatively and 3.6 ± 2.3 cm postoperatively. Compared with preoperative parameters, postoperative reductions in pelvic incidence-lumbar lordosis mismatch averaged 28.7 ± 12.9 degrees, and sagittal vertical axis averaged 7.6 ± 5.2 cm while PJA was essentially unchanged.

CONCLUSIONS

Preliminary results suggest that the distributed loading technique is promising for prevention of PJK with stiffness gradients that mimic the force-deformation curve of the physiologic posterior tension band. Our technique may optimize the degree of stress at the proximal junction without overwhelming the anterior column bony while remodeling and mature arthrodesis takes place.

State of the art: proximal junctional kyphosis-diagnosis, management and prevention

Proximal junctional kyphosis (PJK) is a common problem that may occur following the surgical treatment of adult patients with spinal deformity. It is defined as the proximal junctional sagittal angle from the UIV and UVI + 2 of at least 10° AND at least 10° greater than the preop measurement. The reported incidence of radiographic PJK in the literature varies between 17 and 46%. A smaller subset of these patients may need revision surgery and are defined as proximal junctional failure (PJF), which can be associated with vertebral fracture, vertebral subluxation, failure of instrumentation, and neurological deficits. Several risk factors for development of PJK have been proposed. However, large-scale prospective studies are needed to better identify strategies to reduce the incidence of PJK.

Biomechanical comparison of semirigid junctional fixation techniques to prevent proximal junctional failure after thoracolumbar adult spinal deformity correction

BACKGROUND CONTEXT

Adult spinal deformity patients treated operatively by long-segment instrumented spinal fusion are prone to develop proximal junctional kyphosis (PJK) and failure (PJF). A gradual transition in range of motion (ROM) at the proximal end of spinal instrumentation may reduce the incidence of PJK and PJF, however, previously evaluated techniques have not directly been compared.

PURPOSE

To determine the biomechanical characteristics of five different posterior spinal instrumentation techniques to achieve semirigid junctional fixation, or "topping-off," between the rigid pedicle screw fixation (PSF) and the proximal uninstrumented spine.

STUDY DESIGN

Biomechanical cadaveric study.

METHODS

Seven fresh-frozen human cadaveric spine segments (T8-L3) were subjected to ex vivo pure moment loading in flexion-extension, lateral bending and axial rotation up to 5 Nm. The native condition, three-level PSF (T11-L2), PSF with supplemental transverse process hooks at T10 (TPH), and two sublaminar taping techniques (knotted and clamped) as one- (T10) or two-level (T9, T10) semirigid junctional fixation techniques were compared. The ROM and neutral zone (NZ) of the segments were normalized to the native condition. The linearity of the transition zones over three or four segments was determined through linear regression analysis.

RESULTS

All techniques achieved a significantly reduced ROM at T10-T11 in flexion-extension and axial rotation relative to the PSF condition. Additionally, both two-level sublaminar taping techniques (CT2, KT2) had a significantly reduced ROM at T9-T10. One-level clamped sublaminar tape (CT1) had a significantly lower ROM and NZ compared with one-level knotted sublaminar tape (KT1) at T10-T11. Linear regression analysis showed the highest linear correlation between ROM and vertebral level for TPH and the lowest linear correlation for CT2.

CONCLUSIONS

All studied semirigid junctional fixation techniques significantly reduced the ROM at the junctional levels and thus provide a more gradual transition than pedicle screws. TPH achieves the most linear transition over three vertebrae, whereas KT2 achieves that over four vertebrae. In contrast, CT2 effectively is a one-level semirigid junctional fixation technique with a shift in the upper rigid fixation level. Clamped sublaminar tape reduces the NZ greatly, whereas knotted sublaminar tape and TPH maintain a more physiologic NZ. Clinical validation is ultimately required to translate the biomechanics of various semirigid junctional fixation techniques into the clinical goal of reducing the incidence of proximal junctional kyphosis and failure.

CLINICAL SIGNIFICANCE

The direct biomechanical comparison of multiple instrumentation techniques that aim to reduce the incidence of PJK after thoracolumbar spinal fusion surgery provides a basis upon which clinical studies could be designed. Furthermore, the data provided in this study can be used to further analyze the biomechanical effects of the studied techniques using finite element models to better predict their post-operative effectiveness.

Instrumentation techniques to prevent proximal junctional kyphosis and proximal junctional failure in adult spinal deformity correction-a systematic review of biomechanical studies

BACKGROUND CONTEXT

Correction of adult spinal deformity (ASD) by long segment instrumented spinal fusion is an increasingly common surgical intervention. However, it is associated with high rates of complications and revision surgery, especially in the elderly patient population. The high construct stiffness of instrumented thoracolumbar spinal fusion has been postulated to lead to a higher incidence of proximal junctional kyphosis (PJK) and failure (PJF). Several cadaveric biomechanical studies have reported on surgical techniques to reduce the incidence of PJF/PJK. As yet, no overview has been made of these biomechanical studies.

PURPOSE

To summarize the evidence of all biomechanical studies that have assessed techniques to reduce PJK/PJF following long segment instrumented spinal fusion in the ASD patient population.

STUDY DESIGN

A systematic review.

METHODS

EMBASE and MEDLINE databases were searched for human and animal cadaveric biomechanical studies investigating the effect of various surgical techniques to reduce PJK/PJF following long segment instrumented thoracolumbar spinal fusion in the adult patient population. Studied techniques, biomechanical test methods, range of motion (ROM), intervertebral disc pressure (IDP) and other relevant outcome parameters were documented.

RESULTS

Twelve studies met the inclusion criteria. Four of these studies included non-human cadaveric material. One study investigated the prophylactic application of cement augmentation (vertebroplasty), whereas the remaining studies investigated semi-rigid junctional fixation techniques to achieve a gradual transition zone of forces at the proximal end of a fusion construct, so-called topping-off. An increased gradual transition zone in terms of ROM compared to pedicle screw constructs was demonstrated for sublaminar tethers, sublaminar tape, pretensioned suture loops, transverse hooks and laminar hooks. Furthermore, reduced IDP was found after the application of sublaminar tethers, suture loops, sublaminar tapes and laminar hooks. Finally, two-level prophylactic vertebroplasty resulted in a lower incidence of vertebral compression fractures in a flexion-compression experiment.

CONCLUSIONS

A variety of techniques, involving either posterior semi-rigid junctional fixation or the reinforcement of vertebral bodies, has been biomechanically assessed. However, the low number of studies and variation in study protocols hampers direct comparison of different techniques. Furthermore, determination of what constitutes an optimal gradual transition zone and its translation to clinical practice, would aid comparison and further development of different semi-rigid junctional fixation techniques. Even though biomechanics are extremely important in the development of PJK/PJF, patient-specific factors should always be taken into account on a case-by-case basis when considering to apply a semi-rigid junctional fixation technique.

The Value of Cement Augmentation in Patients With Diminished Bone Quality Undergoing Thoracolumbar Fusion Surgery: A Review

STUDY DESIGN

Systematic review.

OBJECTIVES

Osteoporosis predisposes patients undergoing thoracolumbar (TL) fusion to complications and revision surgery. Cement augmentation (CA) improves fixation of pedicle screws to reduce these complications. The goal of this study was to determine the value and cost-effectiveness of CA in TL fusion surgery.

METHODS

A systematic literature review was performed using an electronic database search to identify articles discussing the cost or value of CA. As limited information was available, the review was expanded to determine the mean cost of primary TL fusion, revision TL fusion, and the prevalence of revision TL fusion to determine the decrease of revision surgery necessary to make CA cost-effective.

RESULTS

Two studies were identified discussing the cost and value of CA. The mean cost of CA for two vertebral levels was $10 508, while primary TL fusion was $87 346 and revision TL fusion was $76 825. Using a mean revision rate of 15.4%, the use of CA for TL fusion would need to decrease revision rates by 13.7% to be cost-effective. Comparison studies showed a decreased revision rate of 11.3% with CA, which approaches this value.

CONCLUSION

CA for TL fusion surgery improves biomechanical fixation of pedicle screws and decreases complications and revision surgery in patients with diminished bone quality. The costs of CA are substantial and reported decreases in revision rates approach but do not reach the calculated value to be a cost-effective technique. Future studies will need to focus on the optimal CA technique to decrease complications, revisions, and costs.

Soft Landing technique as a possible prevention strategy for proximal junctional failure following adult spinal deformity surgery

Background

This cross sectional study describes a "Soft Landing" strategy utilizing hooks for minimizing proximal junctional kyphosis (PJK) and proximal junctional failure (PJF). The technique creates a gradual transition from a rigid segmental construct to unilateral hooks at the upper instrumented level and preservation of the soft tissue attachments on the contralateral side of the hooks. Authors devise a novel classification system for better grading of PJK severity.

Methods

Thirty-nine consecutive adult spinal deformity (ASD) patients at a single institution received the "Soft Landing" technique. The proximal junctional angle was measured preoperatively and at last follow-up using standing 36-inch spinal radiographs. Changes in proximal junctional angle and rates of PJK and PJF were measured and used to create a novel classification system for evaluating and categorizing ASD patients postoperatively.

Results

The mean age of the cohort was 61.4 years, and 90% of patients were women. Average follow up was 2.2 years. The mean change in proximal junctional angle was 8° (SD 7.4°) with the majority of patients (53%) experiencing less than 10° and only 1 patients with proximal junctional angle over 20°. Four patients (10%) needed additional surgery for proximal extension of the uppermost instrumented vertebra (UIV) secondary to PJF.

Conclusions

Soft Landing technique is a possibly effective treatment strategy to prevent PJK and PJF following ASD that requires further evaluation. The described classification system provides management framework for better grading of PJK. The "Soft Landing" technique warrants further comparison to other techniques currently used to prevent both PJK and failure.

Risk and Predictive Factors for Proximal Junctional Kyphosis in Patients Treated by Lenke Type 5 Adolescent Idiopathic Scoliosis Correction

OBJECTIVE

Proximal junctional kyphosis (PJK) is a common sagittal complication of adolescent idiopathic scoliosis (AIS) after corrective surgery, leading to new deformities, pain, and, even, revision surgery. In the present study, we investigated the risk and predictive factors for PJK in patients who had undergone Lenke type 5 AIS correction to identify the parameters relevant to intraoperative guidance.

METHODS

A total of 35 patients with Lenke type 5 AIS who had undergone corrective surgery at our hospital from January 2008 to February 2016 were divided into the PJK (n = 15) and non-PJK (n = 20) groups. Correlation and receiver operating characteristic curve analyses were performed to screen the parameters for significance and calculate the thresholds. A survival analysis was performed to examine the differences between the 2 groups.

RESULTS

Independent t tests revealed significant differences between the 2 groups in the preoperative pelvic incidence, preoperative pelvic tilt, postoperative proximal junctional angle (PJA), and postoperative thoracic kyphosis (TK). The postoperative PJA, postoperative TK, and other parameters correlated significantly with changes in the PJA at the final follow-up. The receiver operating characteristic curves revealed that the postoperative PJA and postoperative TK effectively predicted for the occurrence of PJK, with a threshold of 9.45° and 25.25°, respectively. The estimated survival times were 14.7 months for a PJA >9.45° and TK >25.25°, 19.2 months for a PJA >9.45°, and 33.9 months for TK >25.25°.

CONCLUSIONS

The results of the present study have shown that the postoperative PJA and postoperative TK can be used to effectively predict for the occurrence of PJK in patients with Lenke type 5 AIS after corrective surgery, with a threshold of 9.45° and 25.25°, respectively.

Biomechanics of prophylactic tethering for proximal junctional kyphosis: effects of cyclic loading on tether strength and failure properties

STUDY DESIGN

Biomechanical evaluation of woven polyester tethers.

OBJECTIVES

To quantify changes in tether elongation, stiffness, and failure characteristics after cyclic loading. Ligamentous augmentation is gaining interest as a technique to prevent proximal junctional kyphosis (PJK) in adult spinal fusions. There are a lack of data regarding the effects of cyclic loading on polyester tether mechanical properties. Tether stretch may lead to loss of stabilization and increased risk of tether failure. Biomechanical data are needed to determine the effects of cyclic loading on tether integrity.

METHODS

Testing was done in two materials: (1) a synthetic cortical bone composite to determine baseline mechanical properties, and (2) nine cadaveric L1 spinous processes. 5 mm woven polyester tethers were looped through 2.5 mm holes drilled in each material. First, five tethers were tested directly to failure in the synthetic bone to establish baseline failure properties. Next, tethers were tested at one of the three cyclic load ranges [5%, 25%, and 50% (n = 5 each) of baseline failure] for 1000 cycles and then loaded to failure. Cadaveric tests were done at the 25% range and compared to synthetic bone tests at the same range. Cadaveric failure tests were classified as either tether failure or spinous process bone failure.

RESULTS

Greater cyclic loading range had a significant effect on tether loop elongation, increased stiffness, and decreased ultimate tensile force. Among the cadaveric failure tests, 56% resulted in tether failure and the remaining 44% resulted in bone failure.

CONCLUSIONS

Polyester tethers stretch significantly when loaded to physiological ranges. Anticipation of tether stretch may be an important consideration for a tethering strategy to prevent PJK. Improved understanding of tether material properties can provide guidance for the evaluation of clinical outcomes associated with techniques to reduce the risk of PJK caused by ligamentous laxity.

LEVEL OF EVIDENCE

Biomechanical study.

Complications of thoracic spine surgery - Their avoidance and management

As the surgical techniques have been significantly developed, thoracic spine surgery is currently increasingly indicated for a variety of pathologies such as degenerative spondylosis, ligament ossification, spinal deformity, infectious diseases, trauma and tumors. Thoracic spine has the distinctive anatomy with the rib attachment and the proximity to great vessels and lungs, and spinal cord has particular vulnerability due to its unique circulation system. Thus, both anterior and posterior approach surgeries have their own risks unique to this spinal segment. To be capable of challenging the spinal disorders in thoracic spine, surgeons must be aware of possible complications and their avoidance methods as well as management strategy. In the present narrative review paper, the complications in thoracic spine surgery are categorized into approach-related complications, neurological complications, wound-related complications, mechanical and instrument-related complications, as well as medical complications along with pre-, intra- and post-operative considerations. Their pathologies, possible sequelae, incidence, risk factors, prevention and management are discussed. As for some of the complications that are also commonly seen in cervical or lumbar spine, focus is placed on their importance in thoracic spine surgery. To prevent these adverse events associated with thoracic spine surgery, surgeons should be familiar with detailed knowledge of thoracic anatomy related to its approach as well as physiological characteristics.

Posterior Ligamentous Reinforcement of the Upper Instrumented Vertebrae +1 Does Not Decrease Proximal Junctional Kyphosis in Adult Spinal Deformity

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

Violation of the posterior soft tissues is believed to contribute to the development of proximal junctional kyphosis (PJK). Biomechanical and clinical studies suggest that augmentation of the posterior ligamentous structures (PLS) may help prevent PJK. The purpose of this study was to evaluate the effect of PLS augmentation on the rate of PJK at 1 year.

METHODS

A retrospective single-surgeon cohort study was performed of 108 adult spinal deformity patients who underwent 5 level fusions to the pelvis. Patients were divided into 2 groups: PLS+ patients had reconstruction of the PLS between upper instrumented vertebrae +1 (UIV+1) and UIV-1 with a surgical nylon tape while PLS- patients did not. Demographics, surgical data, and sagittal alignment parameters were compared between the cohorts. The primary outcome of interest was the development of PJK at final follow-up. A subgroup propensity match and logistic regression model were utilized to control for differences in the cohorts.

RESULTS

A total of 108 patients met final criteria, 31 patients (28.7%) were PLS+. There were no differences with regard to preoperative or final sagittal alignment parameters, number of levels fused, rates of 3-column osteotomies, and body mass index (P > .05), though the PLS+ cohort was older and had larger initial sagittal corrections (P < .05). The rates of PJK for PLS+ (27.3%) and PLS- (28.6%) were similar (P = .827). After controlling for sagittal correction via propensity matching, PLS+ had no impact on PJK (29% vs 38.7%, P = .367). In our multivariate analysis, only increased sagittal malalignment and failure to restore sagittal balance were retained as significant predictors of PJK.

CONCLUSION

Even after controlling for extent of correction and preoperative sagittal alignment, PLS reinforcement at UIV+1 using a hand-tensioned nylon tape does not reduce the incidence of PJK at 1 year.

Comparison of Long Segmental Dorsal Stabilization with Complete Versus Restricted Pedicle Screw Cement Augmentation in Unstable Osteoporotic Midthoracic Vertebral Body Fractures: A Biomechanical Study

OBJECTIVE

To compare the construct stability of long-segmental dorsal stabilization in unstable midthoracic osteoporotic fracture situation with complete pedicle screw cement augmentation (ComPSCA) versus restricted pedicle screw cement augmentation (ResPSCA) of the most cranial and caudal pedicle screws.

METHODS

Twelve fresh frozen human cadaveric specimens (Th 4-Th 10) aged 65 years and older were tested in a biomechanical cadaver study. All specimens received a dual-energy X-ray absorption scan and computed tomography scan before testing. Standardized long segmental stabilization was performed. All specimens were matched into pairs. These pairs were randomized into the groups with ComPSCA and ResPSCA. An unstable Th7 fracture was simulated. The maximum load was tested with 6 mm/min until failure or 20 mm had been reached. After testing, a computed tomography scan was performed.

RESULTS

The mean age of the specimens was 87.8 years (range 74-101 years). The mean t score was -3.6 (range -1.2 to -5.3). The mean maximum force in the ResPSCA group was 1600 N (range 1119-1880 N) and 1941 N (1183-3761 N) in the ComPSCA group. No statistically significant differences between both study groups (P = 1.0) could be seen. No signs of screw loosening were visible.

CONCLUSIONS

No statistically significant differences in the maximum loads could be seen. No screw loosening of the non-cemented screws was visible. Thus, the construct stability of long segmental posterior stabilization of an unstable midthoracic fracture using ResPSCA seems to be comparable with ComPSCA under axial compression.

Preoperative and Postoperative Sitting Radiographs for Adult Spinal Deformity Surgery: Upper Instrumented Vertebra Selection Using Sitting C2 Plumb Line Distance to Prevent Proximal Junctional Kyphosis

STUDY DESIGN

Case-control study from a continuous series.

OBJECTIVES

To study the impact of perioperative sitting radiographs in adult spinal deformity (ASD) patients and determine whether proximal junctional kyphosis (PJK) can be prevented using preoperative sitting radiograph.

SUMMARY OF BACKGROUND DATA

Radiographic analysis of ASD comprises standing whole-spine radiography which cannot evaluate the relaxed posture without head-to-foot compensation.

METHODS

Preoperative and postoperative whole-spine standing and sitting radiographs and proximal mechanical complications in surgically treated spinal disorders with a minimum of 1-year follow-up were studied. Whole-spinal alignment was defined by cervical lordosis (CL), sagittal vertical axis (SVA), T1 slope (T1S), thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), and level of kyphotic apex (KA). Proximal mechanical complication was described as a PJK (proximal junctional angle >20°) or reoperation due to proximal junctional failure.

RESULTS

Surgically treated 113 patients were prospectively investigated. Patients were divided into either the ASD (thoracic to ilium posterior corrective fusion), or non-ASD groups. In the ASD group, 10 patients had postoperative PJK, and three revision surgeries were carried out due to PJF with neurological deficit. Comparing standing with sitting positions, CL, TK, and PT became larger, SVA became frontal, LL and SS became smaller, and KA became caudal particularly in the ASD group. Logistic regression analysis demonstrated that the most influenced plumb line for PJK was the upper instrumented vertebra (UIV) to C2 plumb line distance, with a cutoff value of 115 mm for predicting PJK.

CONCLUSION

Our findings highlight the usefulness of sitting spinal alignment evaluation, particularly in ASD patients, with maximum effort of thoracic spine and lower extremity compensation at standing. Mechanical complications such as PJK could be predicted using the distance from the planned UIV to the C2 plumb line in preoperative sitting radiographs.

LEVEL OF EVIDENCE

3.

Risk Factor Analysis of Proximal Junctional Kyphosis after Surgical Treatment of Adult Spinal Deformity with Oblique Lateral Interbody Fusion

Study Design

A single-center retrospective study.

Purpose

To investigate the prevalence of proximal junctional kyphosis (PJK) and its risk factors after surgical treatment of adult spinal deformity (ASD) with oblique lateral interbody fusion (OLIF).

Overview of Literature

Correction of ASD using OLIF has been developed because it is less invasive, and enables correction of severe deformities. Although PJK is a well-recognized complication after the correction of spinal deformity, few studies have evaluated the prevalence and risk factors for PJK after OLIF for ASD.

Methods

We reviewed 74 patients who underwent surgery for ASD. PJK was defined as a proximal junction sagittal Cobb angle exceeding 10°, and at least 10° greater than the preoperative measurement. We investigated the following as risk factors: age, sex, body mass index, medical history, number of fused segments, number of interbody fusions, number of OLIFs, number of osteotomies, level of upper instrumented vertebrae, lowest instrumented vertebrae, and radiographic parameters.

Results

The mean follow-up duration was 22.4 months and the mean age of the patients was 73.6 years. PJK was present in 19/74 patients (25.7%) and absent in 55/74 (74.3%). In the univariate analysis, those with PJK had a significantly higher proportion of patients with a history of vertebral compression fracture (7/19 patients [36.8%] vs. 6/55 patients [10.9%], p=0.027). Those with PJK had a significantly higher proportion of patients with fusion to the pelvis (18/19 patients [94.7%] vs. 34/55 patients [61.8%], p=0.016). According to the multivariate analysis, fusion to the pelvis was a significant risk factor for PJK.

Conclusions

Fusion to the pelvis was the most important risk factor for PJK. A history of vertebral compression fracture served as an additional risk factor for PJK. Clinicians should consider these factors before treating ASD patients with OLIF.

Biomechanical study of space frame structure based on bone cement screw

Stability of space frame structures with bone cement screw reinforcement by biomechanical testing was analyzed. Seven complete human spine specimens with osteoporosis were selected. Three specimens were separated into 18 vertebral bodies. Nine vertebral bodies were randomly selected and bone cement screws were implanted on both sides. Bone cement was used to form a bridge at the front end of the two screws (single vertebral group A). The other nine vertebral bodies were implanted with cement screws on both sides, but the front ends of the two screws were not bridged (single vertebral group B). The remaining spine specimens were used for biomechanical testing of the overall stability of the three-dimensional frame. The four specimens were osteotomized, and then two specimens were randomly selected. Bone cement screws were implanted on both sides of the vertebral body, and a bone cement bridge was formed at the front end of the two screws to establish a three-dimensional frame structure (multi-vertebral group A). The other two spine specimens were implanted with cement screws on both sides of the vertebral body, but the front ends of the two screws were not bridged (multi-vertebral group B). A statistical difference was found between the extractive force of bridged and non-bridged specimens. Group B showed some loosening of screws after the test. The stability of the triangle structure screw, which was formed after the bridge was established at the front end of the single-vertebral bone cement screw, was significantly enhanced. Moreover, the stability was significantly improved after the three-dimensional frame structure was established in the multi-vertebral body group, providing a new method for clinical improvement of the stability and reliability of internal fixation in patients with severe osteoporosis and spinal disease.

Proximal junctional kyphosis following T10-pelvis fusion presenting with neurologic compromise: case presentations and review of the literature

Purpose: Proximal Junctional Kyphosis (PJK) is a well-documented phenomenon following spinal instrumented fusion. Myelopathy associated with proximal junctional failure (PJF) is poorly described in the literature. Adjacent segment disease, fracture above the upper instrumented vertebrae and subluxation may all cause cord compression, ambulatory dysfunction, and/or lower extremity weakness in the postoperative period.Materials and methods: We review the literature on PJK and PJF, and discusses the postoperative management of three patients who experienced myelopathy associated with PJF following T9/10 to pelvis fusion at a single institution.Results and conclusions: PJF with myelopathy must be diagnosed and surgically corrected early on so as to minimize permanent neurologic injury. Patients requiring significant sagittal deformity correction are at greater risk for PJF, and may benefit from constructs terminating in the upper thoracic spine.

Risk Factor Analysis of the Incidence of Subsequent Adjacent Vertebral Fracture After Lumbar Spinal Fusion Surgery with Instrumentation

OBJECTIVE

This study aimed to evaluate the risk factors for adjacent vertebral compression fractures after lumbar spinal fusion with instrumentation.

METHODS

A total of 669 patients who received lumbar instrumented spinal fusion between January 2012 and December 2015 were divided into 2 groups according to whether the adjacent vertebral body was fractured. The covariates recorded were age, sex, bone mineral density, and the number of fixed segments. The anatomic variables were pelvic incidence angle (PI), preoperative lumbar lordosis angle (Pre-LL), postoperative lumbar lordosis angle (Post-LL), Pre-LL minus Post-LL (Loss of LL), postoperative pelvic tilt (Post-PT), postoperative sacral slope, Pre-PI-LL mismatch (Pre-PI minus Pre-LL), and Post-PI-LL mismatch (Post-PI minus Post-LL). A 1-way analysis of variance (ANOVA) was performed with the aforementioned parameters, and binary logistic regression analysis was used to determine the relative risk factors.

RESULTS

The 669 patients were followed-up for a mean of 2.7 ± 1.1 years (range, 2-4 years). Twenty-seven patients demonstrated fractures in the adjacent vertebral body after surgery. Analysis by 1-way ANOVA demonstrated that age, PI, Pre-LL, Post-LL, Loss of LL, Post-PI-LL mismatch, Post-PT, and osteoporosis were potential risk factors (all parameters, P < 0.001). Furthermore, binary logistic regression analysis showed that a large Loss of LL, osteoporosis, and old age were also risk factors for adjacent vertebral compression fractures.

CONCLUSIONS

A greater Loss of LL, osteoporosis, and advanced age may be risk factors for fractures in the adjacent vertebral body of the fixed segment after lumbar fusion fixation.

Effective Prevention of Proximal Junctional Failure in Adult Spinal Deformity Surgery Requires a Combination of Surgical Implant Prophylaxis and Avoidance of Sagittal Alignment Overcorrection

STUDY DESIGN

Propensity score matched analysis of a multi-center prospective adult spinal deformity (ASD) database.

OBJECTIVE

Evaluate if surgical implant prophylaxis combined with avoidance of sagittal overcorrection more effectively prevents proximal junctional failure (PJF) than use of surgical implants alone.

SUMMARY OF BACKGROUND DATA

PJF is a severe form of proximal junctional kyphosis (PJK). Efforts to prevent PJF have focused on use of surgical implants. Less information exists on avoidance of overcorrection of age-adjusted sagittal alignment to prevent PJF.

METHODS

Surgically treated ASD patients (age ≥18 yrs; ≥5 levels fused, ≥1 year follow-up) enrolled into a prospective multi-center ASD database were propensity score matched (PSM) to control for risk factors for PJF. Patients evaluated for use of surgical implants to prevent PJF (IMPLANT) versus no implant prophylaxis (NONE), and categorized by the type of implant used (CEMENT, HOOK, TETHER). Postoperative sagittal alignment was evaluated for overcorrection of age-adjusted sagittal alignment (OVER) versus within sagittal parameters (ALIGN). Incidence of PJF was evaluated at minimum 1 year postop.

RESULTS

Six hundred twenty five of 834 eligible for study inclusion were evaluated. Following PSM to control for confounding variables, analysis demonstrated the incidence of PJF was lower for IMPLANT (n = 235; 10.6%) versus NONE (n = 390: 20.3%; P < 0.05). Use of transverse process hooks at the upper instrumented vertebra (HOOK; n = 115) had the lowest rate of PJF (7.0%) versus NONE (20.3%; P < 0.05). ALIGN (n = 246) had lower incidence of PJF than OVER (n = 379; 12.0% vs. 19.2%, respectively; P < 0.05). The combination of ALIGN-IMPLANT further reduced PJF rates (n = 81; 9.9%), while OVER-NONE had the highest rate of PJF (n = 225; 24.2%; P < 0.05).

CONCLUSION

Propensity score matched analysis of 625 ASD patients demonstrated use of surgical implants alone to prevent PJF was less effective than combining implants with avoidance of sagittal overcorrection. Patients that received no PJF implant prophylaxis and had sagittal overcorrection had the highest incidence of PJF.

LEVEL OF EVIDENCE

3.

Revision surgery in proximal junctional kyphosis

INTRODUCTION

Proximal junctional kyphosis (PJK) is a relatively common complication following spinal deformity surgery that may require reoperation. Although isolating the incidence is highly variable, in part due to the inconsistency in how PJK is defined, previous studies have reported the incidence to be as high as 39% with revision surgery performed in up to 47% of those with PJK. Despite the discordance in reported incidence, PJK remains a constant challenge that can result in undesirable outcomes following adult spine deformity surgery.

METHODS

A comprehensive literature review using Medline and PubMed was performed. Keywords included "proximal junctional kyphosis," "postoperative complications," "spine deformity surgery," "instrumentation failure," and "proximal junctional failure" used separately or in conjunction.

RESULTS

While the characterization of PJK is variable, a postoperative proximal junction sagittal Cobb angle at least 10°, 15°, or 20° greater than the measurement preoperatively, it is a consistent radiographic phenomenon that is well defined in the literature. While particular studies in the current literature may ascertain certain variables as significantly associated with the development of proximal junctional kyphosis where other studies do not, it is imperative to note that they are not all one in the same. Different patient populations, outcome variables assessed, statistical methodology, surgeon/surgical characteristics, etc. often make these analyses not completely comparable nor generalizable.

CONCLUSIONS

The goal of adult spine deformity surgery is to optimize patient outcomes and mitigate postoperative complications whenever possible. Due to the multifactorial nature of this complication, further research is required to enhance our understanding and eradicate the pathology. Patient optimization is the principal guideline in not only PJK prevention, but overall postoperative complication prevention. These slides can be retrieved under Electronic Supplementary Material.

Effectiveness of percutaneous cement injection on proximal junctional failure after posterior lumbar interbody fusion: Preliminary study

Proximal junctional failure (PJF) is the greatest challenge after posterior lumbar interbody fusion (PLIF). The aim of this study was to evaluate the effectiveness of percutaneous cement injection (PCI) for PJF after PLIF patients requiring surgical revision.In this retrospective clinical study, we reviewed 7 patients requiring surgical revision for PJF after PLIF with 18 months follow-up. They received PCI at the collapsed vertebral body and supra-adjacent vertebra, with or without intervertebral disc intervention. The outcome measures were radiographic findings and revision surgery. Two different radiographic parameters (wedging rate (%) of the fractured vertebral body and local kyphosis angle) were used, and were performed before and immediately after PCI, and 18 month after the PCI.In our study, we showed that 5 of 7 patients who experienced PJF after PLIF did not receive any revision surgery after PCI. Immediately after cement injection, the anterior wedging rate (%) and the local kyphosis angle were significantly improved (P = .018, P = .028). The anterior wedging rates (%) and local kyphosis angle, at pre-PCI, immediate after PCI, and at final follow-up, were not significantly different between the non-revision surgery and revision surgery groups.Five of 7 patients who experienced PJF after PLIF did not receive revision surgery after PCI. Considering that general anesthesia and open surgery are high-risk procedures for geriatric patients, our results suggest that non-surgical PCI could be a viable alternative treatment option for PJF.SMC2017-01-011-001. Retrospectively registered 18 January 2017.

Difficulties in Treating Postirradiation Kyphosis in Adults: A Series of Five Cases

STUDY DESIGN

Clinical case series.

OBJECTIVE

To assess objective outcomes of surgical correction of post-external beam radiation therapy (ERBT) kyphosis in a series of five adults.

SUMMARY OF BACKGROUND DATA

EBRT is a well-established treatment for many cancers in children and adults. One complication associated with EBRT is postirradiation spine deformity. Scoliosis is the most common deformity, but kyphosis also occurs frequently. Differences in deformity patterns are likely related to the location and intensity of radiation. To our knowledge, no studies have addressed treatment of these deformities in adults, and the most recent case series (of children) was published in 2005.

METHODS

We present a series of five adults who underwent surgery for postirradiation kyphosis, with a mean follow-up of 3.8 years (range, 2.5-6.2 years).

RESULTS

Surgery improved the kyphotic deformity in all patients. Overall mean kyphotic deformity correction was 56° and was larger for cervical/cervicothoracic deformities (mean, 76°) than for lumbar deformities (mean, 42°) at midterm follow-up. Patients reported significant improvements in pain and self-image. Consistent with prior case series of children, we observed a high rate of complications (mean, 1.4 complications per patient) in adults. Three patients each underwent an unplanned surgical procedure because of a complication.

CONCLUSION

The surgical treatment of postirradiation kyphotic spinal deformity is challenging, with common postoperative complications such as infection, instrumentation failure, and pseudarthrosis. However, with modern surgical techniques and spinal instrumentation, excellent deformity correction can be achieved and maintained. We recommend performing a two-stage procedure for cervicothoracic deformity, with anterior release followed by posterior fusion and instrumentation. In thoracolumbar deformities, correction can be achieved through single-stage posterior fusion. Rigid spinopelvic fixation with sacral-alar-iliac screws and second-stage anterior lumbar interbody fusion at L5-S1 is recommended to reduce nonunion risk. Cement augmentation of proximal and distal anchors can help prevent junctional failure.

LEVEL OF EVIDENCE

Level IV.

Transpedicular-Transdiscal Cement Augmentation Treatment of Thoracolumbar Fusion Proximal Junctional Failure

Background

Long instrumented fusions for adult deformity have a proximal junction kyphosis rate between 20% and 40%. When symptomatic, proximal junctional failure (PJF) often requires revision surgery and is associated with significant morbidity. Vertebral cement augmentation (VCA) has been used for prophylaxis against PJF but has not been previously described as treatment after onset of PJF has occurred. We describe a series of patients with PJF of long posterior spinal fusions that were treated at our institution using a novel VCA technique.

Methods

Three patients with PJF above thoracolumbopelvic fusions were retrospectively reviewed following treatment with transpedicular-transdiscal VCA. The medical record was reviewed for demographic data, outcomes scores, and radiographic images.

Results

Mean age was 69.3 years. Mean follow-up was 13.3 months. Mean preprocedure visual analog scale score was 8.67, and postprocedure visual analog scale score was 4.00. Mean preprocedure sagittal balance was 9.7 cm, and postprocedure sagittal balance was 5.8 cm. No patients required revision surgery for PJF in the follow-up period.

Conclusions

Transpedicular-transdiscal VCA treatment for PJF is safe and may have the potential to prevent the need for revision surgery.

Level of Evidence

4.

Management of Catastrophic Proximal Junctional Failure Following Spinal Deformity Correction in an Adult with Osteogenesis Imperfecta: Case Report and Technical Note

BACKGROUND

Proximal junctional failure (PJF) is a major and sometimes devastating problem following adult spinal deformity (ASD) correction surgery. Common consensus still lags on guidelines for preventing and managing these complications. Surgical treatment of scoliosis in the presence of osteogenesis imperfecta (OI) in the pediatric population is well described. The complication rates are unusually higher in this special subset of patients owing to poor quality of bone. There is a paucity of literature focusing on surgical techniques, strategies, and problems involved in the management of ASD associated with OI.

CASE DESCRIPTION

We report a 59-year-old female with type 1 OI and adult scoliosis who underwent T10-to-pelvis fusion for ASD according to the principles of adult deformity correction. At a 1-year follow-up, she presented with asymptomatic proximal junctional kyphosis of 45° and 2 weeks later had PJF along with spinal cord injury after a fall. On computed tomography scan, kyphosis was increased to 60° at T9-T10. She underwent decompression and revision deformity correction using quadruple rods, with extension of instrumentation to T2 with soft landing using rib bands. At a 4-year follow-up, she had a good functional outcome after revision surgery.

CONCLUSIONS

This is the first report of successful management of PJF following ASD correction in the presence of OI using this technique. Suboptimal hold of implants due to poor bone quality must be at the focus of any surgical planning for these patients. All possible strategies to prevent PJF must be considered when planning the deformity correction in adults with OI.

Percutaneous Vertebral Body Augmentations: The State of Art

Osteoporotic compression fractures of the vertebral body can result in pain and long-term morbidity, including spinal deformity, with increased risk of mortality resulting from associated complications. Conservative management includes opioids and other analgesics, bed rest, and a back brace. For patients with severe and disabling pain, vertebral augmentation (vertebroplasty and kyphoplasty) is often considered, with these procedures endorsed by multiple professional societies, and provides immediate structural support, and stabilizes and reinforces the weakened bone structure. The purpose of this article is to review the vertebral biomechanics, indications and contraindications, and techniques of performing successful vertebral augmentation.