Vertebroplasty and Vertebral Augmentation Techniques

Keeping it "straight": how to do spinal tumor ablation with vertebral augmentation

This technical review provides a comprehensive overview of spinal tumor ablation and vertebral augmentation. These percutaneous minimally invasive procedures offer significant survival and palliative pain relief benefits for patients with pathological vertebral fractures. Vertebral augmentation, which includes vertebroplasty and kyphoplasty, involves injecting cement into fractured vertebral bodies to restore height. While vertebroplasty involves the direct injection of cement into a fractured vertebral body, kyphoplasty involves using a balloon to create a low-pressure cavity to allow for cement injection to restore the vertebral body height. Over the years, this technique has evolved into a straightforward process, though it presents certain technical challenges discussed in this article.

Prophylactic vertebral cement augmentation at the uppermost instrumented vertebra and rostral adjacent vertebra for the prevention of proximal junctional kyphosis and failure following long-segment fusion for adult spinal deformity

BACKGROUND CONTEXT

Proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) are common problems after long-segment (>5 levels) thoracolumbar instrumented fusions in the treatment of adult spinal deformity (ASD). No specific surgical strategy has definitively been shown to lower the risk of PJK as the result of a multifactorial etiology.

PURPOSE

The study aimed to assess the incidence of PJK and PJF in patients treated with prophylactic polymethylmethacrylate (PMMA) cement augmentation at the uppermost instrumented vertebrae (UIV) and rostral adjacent vertebrae (UIV+1).

STUDY DESIGN/SETTING

This is a retrospective cohort-matched surgical case series at an academic institutional setting.

PATIENT SAMPLE

Eighty-five adult patients over a 16-year enrollment period were identified with long-segment (>5 levels) posterior thoracolumbar instrumented fusions for ASD.

OUTCOME MEASURES

Primary outcomes measures were PJK magnitude and PJF formation. Secondary outcomes measures were spinopelvic parameters, as well as global and regional sagittal alignment.

METHODS

The impact of adjunctive PMMA use in long-segment (≥5 levels) fusion for ASD was assessed in adult patients aged 18 and older. Patients were included with at least one of the following: lumbar scoliosis >20°, pelvic tilt >25°, sagittal vertical axis >5 cm, central sacral vertical line >2 cm, and thoracic kyphosis >60°. The frequency of PJF and the magnitude of PJK were measured radiographically preoperatively, postoperatively, and at maximum follow-up in controls (Group A) and PMMA at the UIV and UIV+1 (Group B).

RESULTS

Eighty-five patients (64±11.1 years) with ASD were identified: 47 control patients (58±10.6) and 38 patients (71±6.8) treated with PMMA at the UIV and UIV+1. The mean follow-up was 27.9 and 24.2 months in Groups A and B, respectively (p=.10). Preoperative radiographic parameters were not significantly different, except the pelvic tilt which was greater in Group A (26.6° vs. 31.4°, p=.03). Postoperatively, the lumbopelvic mismatch was greater in Group B (14.6° vs. 7.9°, p=.037), whereas the magnitude of PJK was greater in controls (9.36° vs. 5.65°, p=.023). The incidence of PJK was 36% (n=17) and 23.7% (n=9) in Groups A and B, respectively (p=.020). The odds ratio of PJK with vertebroplasty was 0.548 (95% confidence interval=0.211 to 1.424). Proximal junctional kyphosis was observed in 6 (12.8%) controls only (p=.031). The UIV+1 angle, a measure of PJK, was significantly greater in controls (10.0° vs. 6.8°, p=.02). No difference in blood loss was observed. No complications were attributed to PMMA use.

CONCLUSIONS

The use of prophylactic vertebral cement augmentation at the UIV and rostral adjacent vertebral segment at the time of deformity correction appears to be preventative in the development of proximal junctional kyphosis and failure.

The effect of prophylactic vertebroplasty on the incidence of proximal junctional kyphosis and proximal junctional failure following posterior spinal fusion in adult spinal deformity: a 5-year follow-up study

BACKGROUND CONTEXT

The incidence of proximal junctional kyphosis (PJK) ranges from 5% to 46% following adult spinal deformity surgery. Approximately 66% to 76% of PJK occurs within 3 months of surgery. A subset of these patients, reportedly 26% to 47%, develop proximal junctional failure (PJF) within 6 months postoperatively. To date, there are no studies evaluating the impact of prophylactic vertebroplasty on PJK and PJF incidence at long-term follow-up.

PURPOSE

The purpose of this study is to evaluate the long-term radiographic and clinical outcomes, and incidence of PJK and PJF, after prophylactic vertebroplasty for long-segment thoracolumbar posterior spinal fusion (PSF).

STUDY DESIGN

This is a prospective cohort study.

PATIENT SAMPLE

Thirty-nine patients, of whom 87% were female, who underwent two-level prophylactic vertebroplasty at the upper instrumented and supra-adjacent vertebrae at the time of index PSF were included in this study.

OUTCOME MEASURES

Clinical outcomes were assessed using the Scoliosis Research Society-22 (SRS-22), and Short-Form (SF) 36 questionnaires, and the Oswestry Disability Index (ODI). Radiographic parameters including PJK angle, and coronal and sagittal alignment, were calculated, along with relevant perioperative complications and revision rates.

METHODS

Of the 41 patients who received two-level prophylactic vertebroplasty at the upper instrumented and supra-adjacent vertebrae at the time of index PSF, and comprised a cohort with previously published 2-year follow-up data, 39 (95%) completed 5-year follow-up (average: 67.6 months). Proximal junctional kyphosis was defined as a change in the PJK angle ≥10° between the immediate postoperative and final follow-up radiograph. Proximal junctional failure was defined as acute proximal junctional fracture, fixation failure, or kyphosis requiring extension of fusion within the first 6 months postoperatively.

RESULTS

Thirty-nine patients with a mean age of 65.6 (41-87) years were included in this study. Of the 39 patients, 28.2% developed PJK (11: 7.7% at 2 years, 20.5% between 2 and 5 years), and 5.1% developed acute PJF. Two of the 11 PJK patients required revision for progressive worsening of the PJK. There were no proximal junctional fractures. There was no significant difference in preoperative, immediate postoperative, and final follow-up measurements of thoracic kyphosis, lumbar lordosis, and coronal or sagittal alignment between patients who developed PJK, PJF, or neither (p>.05). There was no significant difference in ODI, SRS-22, or SF-36 scores between those with and without PJK or PJF (p>.05).

CONCLUSIONS

This long-term follow-up demonstrates that prophylactic vertebroplasty may minimize the risk for junctional failure in the early postoperative period. However, it does not appear to decrease the incidence of PJK at 5 years.

Synthesis and characterization of an injectable and self-curing poly(methyl methacrylate) cement functionalized with a biomimetic chitosan–poly(vinyl alcohol)/nano-sized hydroxyapatite/silver hydrogel

Preparation and characterizations of injectable p-PMMA/CS–PVA/Nano-HA/Ag⁺ cements.

Computational modelling of bone augmentation in the spine

Computational models are gaining importance not only for basic science, but also for the analysis of clinical interventions and to support clinicians prior to intervention. Vertebroplasty has been used to stabilise compression fractures in the spine for years, yet there are still diverging ideas on the ideal deposition location, volume, and augmentation material. In particular, little is known about the long-term effects of the intervention on the surrounding biological tissue. This review aims to investigate computational efforts made in the field of vertebroplasty, from the augmentation procedure to strength prediction and long-term in silico bone biology in augmented human vertebrae. While there is ample work on simulating the augmentation procedure and strength prediction, simulations predicting long-term effects are lacking. Recent developments in bone remodelling simulations have the potential to show adaptation to cement augmentation and, thus, close this gap.

Percutaneous vertebroplasty with the rotational fluoroscopy imaging technique

OBJECTIVE

To evaluate the feasibility of the rotational angiography unit (RAU) as a single technique to guide percutaneous vertebroplasty (PVP).

MATERIALS AND METHODS

Twenty-five consecutive patients (35 vertebral bodies, 20 lumbar and 15 thoracic) were treated using RA fluoroscopy. Using a state-of-the-art flat-panel angiographer (Artis zee, Siemens, Erlangen, Germany), rotational acquisitions were obtained in all patients for immediate post-procedure 2D/3D reconstructions. Pre- and postoperative back pain was assessed with the visual analog scale (VAS). Fluoroscopy time, patient radiation dose exposure, technical success, mean procedure time, mean number of rotational acquisitions and procedural complications were recorded. All features were compared with a historical cohort of patients (N = 25) who underwent PVP under CT and mobile C-arm fluoroscopy guidance.

RESULTS

In all cases, safe and accurate control of the needle insertion and bone-cement injection was successfully obtained with high-quality fluoroscopy images. One cement leakage was detected in the RAU group, and two leakages were detected in the CT and C-arm fluoroscopy group. Technical features were significantly different between the two groups (RAU vs. CT): mean procedure time: 38.2 min vs. 60.2 min (p = 0.02); median fluoroscopy time: 14.58 and 4.58 min (p = 0.02); median number of rotational acquisitions: 5 vs. 10 (p = 0.02); mean patient dose: 6 ± 1.3 mSv vs. 23 ± 1.3 mSv (p = 0.02). There were minor complications (pain, small hematoma) in two patients (8%) in the study group and three cases (12%) in the control group.

CONCLUSION

RAU guidance is an effective and safe technique for performing PVP because it reduces the procedural time and radiation exposure.

Assessing cement injection behaviour in cancellous bone: An in vitro study using flow models

Understanding the cement injection behaviour during vertebroplasty and accurately predicting the cement placement within the vertebral body is extremely challenging. As there is no standardized methodology, we propose a novel method using reproducible and pathologically representative flow models to study the influence of cement properties on injection behaviour. The models, confined between an upper glass window and a lower aluminium plate, were filled with bone marrow substitute and then injected (4, 6 and 8 min after cement mixing) with commercially available bone cements (SimplexP, Opacity+, OsteopalV and Parallax) at a constant flow rate (3 mL/min). A load cell was used to measure the force applied on the syringe plunger and calculate the peak pressure. A camera was used to monitor the cement flow during injection and calculate the following parameters when the cement had reached the boundary of the models: the time to reach the boundary, the filled area and the roundness. The peak pressure was comparable to that reported during clinical vertebroplasty and showed a similar increase with injection time. The study highlighted the influence of cement formulations and model structure on the injection behaviour and showed that cements with similar composition/particle size had similar flow behaviour, while the introduction of defects reduced the time to reach the boundary, the filled area and the roundness. The proposed method provides a novel tool for quick, robust differentiation between various cement formulations through the visualization and quantitative analysis of the cement spreading at various time intervals.

Chronic obstructive pulmonary disease (COPD) patients with osteoporotic vertebral compression fractures (OVCFs): improvement of pulmonary function after percutaneous vertebroplasty (VTP)

OBJECTIVES

To investigate the changes of respiratory function in patients affected by chronic obstructive pulmonary disease (COPD) with single dorsal osteoporotic vertebral compression fractures (OVCFs) treated with vertebroplasty (VTP).

METHODS

Forty-five patients affected by COPD and single dorsal OVCF underwent VTP (29 men, 16 women; mean age 71.4 years, range 65-77 years). Inclusion criteria were magnetic resonance findings of bone marrow oedema, without intracanal bone fragments and refractory pain to medical treatment for at least 3 months. Osteoporosis was assessed by bone densitometry. Spirometry was performed before and after treatment.

RESULTS

A significant VAS-score decrease was observed 1 week after VTP, with a subsequent decrease over time; vital capacity (VC) and forced vital capacity (FVC) improved over time, reaching a plateau at 3 months. Forced expiratory volume at 1 s (FEV1) did not significantly differ between the pre-VTP values and follow-up values. A significant correlation was observed between VAS-score values and VC, and VAS-score values and FVC. No significant correlation was observed between VAS-score values and FEV1 values.

CONCLUSIONS

VTP improves restrictive ventilatory impairment in patients with moderate and severe COPD affected by single thoracic OVCFs. We recommend this treatment in the management of these patients.

KEY POINTS

• Osteoporosis is a major comorbidity in chronic obstructive pulmonary disease (COPD) patients. • Pain due to osteoporotic vertebral compression fractures worsens respiratory failure in COPD. • Vertebroplasty improves ventilatory impairment in COPD patients with osteoporotic vertebral compression fractures.

Surgical treatment of cervical vertebral hemangioma associated with adjacent cervical spondylotic myelopathy

BACKGROUND CONTEXT

Symptoms may vary from simple vertebral pain to progressive neurologic deficit because of cervical vertebral hemangioma associated with adjacent cervical spondylotic myelopathy (CVHAWACSM). Often resistant to conservative medical treatment, surgery has been the treatment of choice for these patients, but the optimal surgical strategy for CVHAWACSM has not been defined.

PURPOSE

This study aimed to investigate the methods and efficacy in the treatment of CVHAWACSM.

STUDY DESIGN

Retrospective review of patients enrolled in prospective randomized trial.

PATIENT SAMPLE

Procedure was performed in 18 patients (11 men and 7 women) with CVHAWACSM, who were enrolled between January 2006 and September 2011.

OUTCOME MEASURES

Radiographic examinations were carried out to assess total filling of polymethylmethacrylate in the vertebral body, fusion rates, implant failure, and general complications. The recovery of neurologic function and neck and shoulder pain relief were measured based on the Japanese Orthopedic Association (JOA) and the visual analog scale (VAS) scores.

METHODS

Eighteen patients had single vertebral hemangioma, including one case at C₃, three at C₄, six at C₅, five at C₆, and three at C₇. The X-ray films showed a typical "palisade" change. According to the clinical and imaging features, there were 12 cases of Type II and 6 of Type IV cervical hemangioma. Standard anterior cervical decompression and fusion with a stand-alone polyetheretherketone cage (filled with autologous cancellous iliac bone) was performed, followed by vertebroplasty. Clinical and radiologic follow-ups were performed.

RESULTS

The mean follow-up was 24.1 months, with a range of 18 to 36 months. The symptoms of all 18 patients were improved, by varying degrees, and the lesion vertebra did not show anterior bone cement leakage or injuries in the spinal cord and nerves. The forming vertebra did not show fracture or collapse, and there was no recurrence of the hemangioma. During the follow-up, there was no implant loosening, displacement, or breakage. The JOA and the VAS scores were significantly recovered at 3 months after the operation and in the last follow-up, compared with the preoperative level (p<.05). The JOA scores in the last follow-up showed 13 excellent, 4 good, 1 fair, and 0 poor cases.

CONCLUSIONS

This procedure seems to be a safe efficient method to treat symptomatic CVHAWACSM. It seems to serve the purpose of providing vertebral augmentation, cord decompression, and rigid fusion at the same sitting. Although the present outcomes are promising, long-term follow-up studies with larger patient numbers are required to confirm this effect.

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

BACKGROUND CONTEXT

Vertebral compression fractures at the proximal junction are common complications of long spinal fusion surgeries that can contribute to the development of proximal junctional kyphosis or proximal junctional failure. To our knowledge, no biomechanical studies have addressed the effect of vertebral augmentation at the proximal junction.

PURPOSE

To evaluate the effectiveness of prophylactic vertebroplasty in reducing the incidence of vertebral compression fractures at the proximal junction after a long spinal fusion in a cadaveric spine model.

STUDY DESIGN

Biomechanical cadaveric study.

METHODS

We divided 18 cadaveric spine specimens into three groups of six spines each: a control group, a group treated with one-level prophylactic vertebroplasty at the upper instrumented vertebra, and a group treated with two-level prophylactic vertebroplasty at the upper instrumented vertebra and the supra-adjacent vertebra. In all spines, the pedicles were instrumented from L5 to T10. Using eccentric axial loading, the specimens were then compressed until failure. Failure was defined as a precipitous decrease in load with increasing compression. The effect of augmentation on load-to-failure was checked using linear regression. The effect of augmentation on incidence of adjacent fractures was checked using logistic regression. Differences at the level of p<.05 were considered significant. KyphX cement introducer was donated by Kyphon, and the pedicle screws were donated by DePuy.

RESULTS

Fractures occurred in 12 of 18 specimens: five in the control group, six in the one-level group, and only one in the two-level group; these differences were statistically significant.

CONCLUSIONS

Prophylactic vertebroplasty at the upper instrumented level and its supra-adjacent vertebra reduced the incidence of junctional fractures after long posterior spinal instrumentation in this axially loaded cadaveric model. Additional studies are necessary to determine if these results are translatable to clinical practice.

Neurological deficit due to cement extravasation following a vertebral augmentation procedure

The authors endeavor to highlight the surgical management of severe neurological deficit resulting from cement leakage after percutaneous vertebroplasty and to systematically review the literature on the management of this complication. A patient presented after a vertebroplasty procedure for traumatic injury. A CT scan showed polymethylmethacrylate leakage into the right foramina at T-11 and L-1 and associated central stenosis at L-1. He underwent decompression and fusion for removal of cement and stabilization of the fracture segment. In the authors' systematic review, they searched Medline, Scopus, and Cochrane databases to determine the overall number of reported cases of neurological deficit after cement leakage, and they collected data on symptom onset, clinical presentation, surgical management, and outcome. After surgery, despite neurological recovery postoperatively, the patient developed pneumonia and died 16 days after surgery. The literature review showed 21 cases of cement extravasation with neurological deficit. Ultimately, 15 patients had resolution of the postoperative deficit, 5 had limited change in neurological status, and 2 had no improvement. Cement augmentation procedures are relatively safe, but certain precautions should be taken to avoid such complications including high-resolution biplanar fluoroscopy, considering the use of a local anesthetic, and controlling the location of cement spread in relationship to the posterior vertebral body. Immediate surgical intervention with removal of cement provides good results with complete recovery in most cases.

Clinical evaluation of percutaneous vertebroplasty in a patient with paraplegia and immobilization syndrome: a case report

We will discuss a potential role of percutaneous vertebroplasty (PVP) in the management of a patient with immobilization syndrome due to paraplegia and vertebral osteoporotic fractures. While PVP is commonly used for the treatment of osteoporotic thoracolumbar vertebral compression fractures, its role in vertebral stabilization in patient with immobilization syndrome has not been reported in the literature. A 73-year-old woman affected by immobilization syndrome due to paraplegia and vertebral osteoporotic fractures was treated with PVP of vertebrae D12, L1, and L4. After PVP, the patient did not need any antalgic therapy, and there was a significant improvement regarding mobilization, performance of physiological functions, daily management of personal care, and treatment of decubitus ulcers, increasing life quality and psychological well-being.

Preliminary Results of the Effect of Prophylactic Vertebroplasty on the Incidence of Proximal Junctional Complications After Posterior Spinal Fusion to the Low Thoracic Spine

STUDY DESIGN

Prospective cohort study.

OBJECTIVE

To evaluate, in adults undergoing posterior spinal fusions, 1) the effect of prophylactic vertebroplasty on the incidence of proximal junctional kyphosis (PJK) and proximal junctional failure (PJF), and 2) the difference in outcomes between those who did and did not develop PJK or PJF.

SUMMARY OF BACKGROUND DATA

Proximal junctional kyphosis occurs in 20% to 39% of adults after posterior spinal fusions; a subset develops PJF.

METHODS

From 2005 through 2008, we treated 41 consecutive patients (40 years old or more) with spinal deformity with 2-level prophylactic vertebroplasty (at the upper instrumented vertebrae and the supra-adjacent vertebrae) during posterior spinal fusion. The 38 patients with 24 months' follow-up formed our study group. We measured patient outcomes with the Scoliosis Research Society-24 questionnaire, the Oswestry Disability Index, and the 12-item Short Form Survey. All patients completed each assessment preoperatively, and 89% or more did so postoperatively. We compared postoperative and final follow-up radiographs to identify the PJK incidence (ie, a PJK angle change of 10° or more), and analyzed the PJK, PJF, and non-PJK/PJF groups for outcome scores with Student t test and chi-square test (significance, p < .05).

RESULTS

Three patients (8%) developed PJK and 2 (5%) developed PJF, markedly lower incidences than those previously reported. At final follow-up, patients with PJK or PJF reported statistically significant lower pain and satisfaction Scoliosis Research Society-24 scores than did patients in the non-PJK/PJF group, but there were no significant differences in Scoliosis Research Society-24 mental health or function scores between groups. All patients had significant improved Oswestry Disability Index and 12-item Short Form Survey scores.

CONCLUSIONS

Prophylactic vertebroplasty in long posterior spinal fusions for adult spinal deformity resulted in a low incidence of PJF and PJK, with only small differences in outcome scores between those who did and did not develop PJK and PJF.

Strategies towards injectable, load-bearing materials for the intervertebral disc: a review and outlook

Currently available treatments for the degenerated intervertebral disc present disadvantages, such as surgical invasiveness and inadequate load distribution results. Load-bearing, injectable materials may be interesting for future therapies, but have not been studied in depth. In this study, the existing literature was screened for studies on injectable materials for the intervertebral disc and a rationale for load-bearing, injectable materials was formulated. Requirements for such a material were discussed, partly based on the experience of materials used for similar applications. Important properties were discussed and found to include biocompatibility, bioactivity, porosity, handling, injectability, working time, setting time, radiopacity, containment and mechanical properties, where several of these properties are linked to one another. In conclusion, there is a need for consensus on the properties of new materials developed for use in minimally invasive procedures in the spine. A substantial amount of attention may need to be given to non-toxic setting reactions.

Interventional management of cancer pain

PURPOSE OF REVIEW

Interventional techniques were the mainstay for cancer pain management before the WHO ladder and opioids were freely available. The three-step WHO ladder has its limitations, and cancer pain is often under treated. Advances in treatment options mean that cancer patients are living longer and pain interventions may have a role to play even early in the cancer diagnosis for better quality of analgesia. The role of high doses of opioids in pain management is also currently under scrutiny.

RECENT FINDINGS

Recent advances in intrathecal analgesia, radiofrequency techniques, both in tumour ablation and neurotomies, are being widely used for palliation. Vertebroplasty techniques have been used not only for pain relief, but also for stabilization. Improved imaging and thoracoscopic techniques have made coeliac plexus and splanchnic blockade safer and more efficacious. There has been recent interest in percutaneous cordotomy with newer techniques using computed tomography/MRI and endoscopy guidance. Percutaneous electrical nerve stimulation and 8% capsaicin patches have been successfully used for managing neuropathic pain in cancer.

SUMMARY

Interventions form an integral part in providing pain relief in complex cancer pains. Oncologists and palliative care physicians are to be educated on the usefulness and timing of interventions in the management of complex cancer pain.