Surgically controlled, transpedicular methyl methacrylate vertebroplasty with fluoroscopic guidance

Bone Cement and Pedicle Screw for the Treatment of Spinal Tumors with Spinal Cord Compression and Posterior Wall Defects

OBJECTIVE

To compare the safety and efficacy of posterior internal fixation with open vertebroplasty (VP) and posterior internal fixation with open kyphoplasty (KP) in the treatment of metastatic epidural spinal cord compression (MESCC) with posterior wall destruction.

METHODS

This retrospective study, conducted between January 2016 and May 2019, equally divided 60 patients with MESCC and posterior wall destruction into two groups based on the surgical method: open vertebroplasty with pedicle screw fixation (VP group) and open kyphoplasty with pedicle screw fixation (KP group). Visual analogue scale (VAS), SF-36 scores, middle vertebral height (MVH), and posterior vertebral height (PVH) were evaluated for the two groups preoperatively, postoperatively, and 1 year after surgery. Spinal Instability Neoplastic Score, Frankel grades and complications were recorded and evaluated.

RESULTS

Five patients were excluded from the analysis, and our study cohort consisted of 55 adult patients who met the inclusion criteria. The VAS and SF-36 scores of these two groups of patients significantly improved, when compared with those before the surgery (P < 0.05). There were significant differences in total cost (8835 ± 1468 vs 9540 ± 053 USD) and cement volume (4.51 ± 0.96 ml vs 6.35 ± 1.09 ml) between two groups (P < 0.05). The MVH and PVH of these two groups of patients significantly improved, when compared with those before the surgery (P < 0.05). The MVH was significantly larger in the KP group than in the VP group postoperatively (20.15 ± 4.86 vs 17.70 ± 3.78, P < 0.05) and at the final follow-up (20.42 ± 5.59 vs 17.28 ± 3.23, P < 0.05). However, the PVH of the two groups did not significantly differ at the two postoperative follow-ups (P > 0.05). No significant differences were found in surgery time, time from surgery to discharge, blood loss and complications between both groups postoperatively (P > 0.05).

CONCLUSION

In the short term, both approaches are effective and safe in patients with MESCC and posterior wall destruction. The posterior internal fixation with open VP may be a good choice of surgical method in patients with MESCC and posterior wall defects.

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.

Quantitative T2 Mapping Shows Increased Degeneration in Adjacent Intervertebral Discs Following Kyphoplasty

OBJECTIVE

A minimally invasive treatment of osteoporotic and nonosteoporotic thoracic and lumbar spine fractures is cement augmentation (kyphoplasty). Little is known about the impact on adjacent intervertebral discs. A quantitative magnetic resonance imaging (MRI) approach in addition to morphological MRI is desirable to evaluate changes in the intervertebral disc. Our study aims to evaluate the feasibility of T2 mapping for the detection of subtle changes in the intervertebral discs in spines after kyphoplasty.

DESIGN

Intervertebral discs were assessed by quantitative MRI (3.0 T) using T2 relaxation time mapping. Region of interest (ROI; 6 per disc) analyses were performed. The ROIs at the anterior and posterior edges were interpreted as annulus fibrosus (AF). The 2 very inner zones were regarded as nucleus pulposus (NP) and the regions in between as intermediate transition zone. We compared T2 relaxation time values of intervertebral discs adjacent to the vertebrae after kyphoplasty with those nonadjacent to vertebrae after kyphoplasty, especially in the NP.

RESULTS

The analysis of the ROIs showed that the intervertebral discs of the adjacent vertebral segments are associated with reduced T2 values compared to those that are nonadjacent to the affected vertebrae.

CONCLUSION

This study is to our knowledge the first investigation of intervertebral discs after kyphoplasty by quantitative MRI. Quantitative T2 mapping shows increased degeneration in adjacent intervertebral discs following kyphoplasty. Besides its contribution to a broader knowledge of postoperative changes after kyphoplasty, our findings may help to improve differentiation between healthy and degenerated intervertebral discs using these techniques.

Open Kyphoplasty for Metastatic Spine Disease: A Retrospective Clinical Series

OBJECTIVE

Symptomatic metastatic spine disease (MSD), is a challenging disease involving 3%-20% of patients with bone metastases. Different surgical options are available and must be tailored to the general and neurologic conditions of the patients. Open kyphoplasty (OKP) refers to decompressive hemilaminectomy, associated with a contralateral percutaneous kyphoplasty, and in some cases, to a posterior stabilization. The aim of the study was to critically review our experience during the last decade with OKP in patients with cancer.

METHODS

Fifty-three patients with cancer underwent OKP for symptomatic MSD. The Tokuhashi score and Spinal Instability Neoplastic Score were calculated for each patient. Length of hospital stay, perioperative complications, incidence of adjacent-level fractures, and median survival after surgery were evaluated. Karnofsky Performance Status, visual analog scale, and Dennis Pain Score were calculated preoperatively, postoperatively, and at last follow-up.

RESULTS

Median Tokuhashi score and Spinal Instability Neoplastic Score were 10 and 10, respectively. The mean volume of filling material inserted was 3.6 mL. Median operative time was 180 minutes. Complications included 8 leakages (15%), 2 permanent motor deficits (3.8%), and 2 asymptomatic pulmonary embolisms (3.8%). Mean length of hospital stay was 7 days. A significant improvement was observed in Karnofsky Performance Status, visual analog scale score, and Dennis Pain Score (P < 0.0001). Median follow-up was 16 months and overall survival 22 months.

CONCLUSIONS

OKP was an effective treatment of symptomatic MSDs in selected oncologic patients with low Tokuhashi scores. It relieved lateral epidural compressions, expanded indications of palliative surgery in patients who were not otherwise surgical candidates, and rapidly dealt with cement leakages.

Quality of Life Comparison between Vertebroplasty and Kyphoplasty in Patients with Osteoporotic Vertebral Fractures

Study Design

Retrospective evaluation.

Purpose

To compare quality of life in postmenopausal women with osteoporotic vertebral fractures (OVFs) who underwent vertebroplasty (VP) or kyphoplasty (KP).

Overview of Literature

Patient with OVFs who do not respond to conservative treatment can be treated with VP or ballon KP for faster pain relief. There are controversies on which procedure is more effective.

Methods

Five hundred twenty-eight postmenopausal women in nationwide hospitals with age of 50 years or older who underwent VP of KP for OVFs were enrolled in this study. Health related quality of life was measured using the European Quality of Life 5 Domains (EQ-5D) and visual analogue scale (VAS).

Results

In the VP group, average EQ-5D dimension was 1.95 in mobility, 1.86 in self care, 2.02 in usual activity, 2.19 in pain, 1.69 in anxiety or depression. In the KP group, average EQ-5D dimension was 1.83 in mobility, 1.78 in self care, 1.98 in usual activity, 2.03 in pain, 1.55 in anxiety or depression. Quality of life of KP group was significantly better than that of the VP group in mobility (p=0.016), pain (p=0.001), and anxiety or depression (p=0.008). Average EQ-5D index of the VP and the KP group was 0.353 (±0.472) and 0.485 (±0.357), respectively. The EQ-5D index of the KP group was significantly (p<0.001) higher than that of the KP group. The difference of VAS between VP and KP group was not statistically significant (p=0.580).

Conclusions

Quality of life in patient with OVFs who underwent KP was significantly better than that of patients who underwent VP.

Intra-operative vertebroplasty combined with posterior cord decompression. A report of twelve cases

Percutaneous vertebroplasty (VP) is a minimally invasive technique for the treatment of vertebral pathology providing early vertebral stabilization and pain relief. In cases of vertebral pathology complicated by spinal cord compression with associated neurological deficits, VP alone cannot be performed free of risks. We describe a combined approach in which decompressive laminectomy and intra-operative vertebroplasty (IVP) are performed during a single session. Among the 252 VP performed in our centre in the past three years, 12 patients (12 vertebral levels) with different pathologies (six symptomatic haemangiomas, two metastatic fractures, four osteoporotic fractures) were treated with an open procedure combined with surgery. All cases were treated with decompressive laminectomy and IVP (mono/bipeduncular or median-posterior trans-somatic access). Five patients with symptomatic haemangiomas were treated with endovascular embolization prior to the combined approach. A visual analogue scale (VAS) was applied to assess pain intensity before and after surgery. The neurological deficits were evaluated with an ASIA impairment scale. In all cases benefit from pain and neurological deficits was observed. The mean VAS score decreased from 7.8 to 2.5 after surgery. The ASIA score improved in all cases (five cases from D to E and five cases from C to D). No clinical complications were observed. In one case a CT scan performed after the procedure showed a foraminal accumulation of PMMA, but the patient referred no symptoms. IVP can be successfully applied in different pathologies affecting the vertebrae. In our limited series this approach proved safe and efficient to provide decompression of spinal cord and dural sac and vertebral body stabilization in a single session.

Magnetic resonance imaging changes of intervertebral discs after kyphoplasty

BACKGROUND

Minimal-invasive cement augmentation techniques gained popularity recently. Long-term studies, however, are still not available focusing on the effect of possible acceleration of intervertebral disc degeneration.

MATERIALS AND METHODS

Fifteen patients (average age 67.1 ± 6.9 years, range 58-77; 10 female, 5 male) with acute or osteoporotic fractures were included in this study and MRI scans were performed before surgery and after a mean follow-up period of 15.2 months (range 8-27 months). Out of these patients, seven were available for a long-term MRI scan after a mean of 94.3 months (range 84-96 months). Disc degeneration and injuries were graded according to published Pfirrmann and Oner scales.

RESULTS

A total of 43 intervertebral discs with moderate initial degeneration were examined pre-operatively and at the first follow-up. Twenty were available for the long-term-follow-up. At the first follow-up, 3 (1.3 %) discs showed a degenerative progression of 1 grade compared to the pre-operative MRI. Only one injured and one uninjured disc (0.4 %) showed progressive degeneration of 1 grade in the long-term follow up. No intervertebral disc in-between bisegmental cement augmentation showed acceleration of degenerative changes.

CONCLUSION

Despite several limitations regarding patients' age and lack of performed perfusion MRI scans, this study suggests that vertebral cement augmentation through kyphoplasty has no significant influence on disc degeneration even after a long period. The absence of severe disc degeneration after vertebral augmentation supports further clinical trials, which should incorporate endplate perfusion studies for detailed information regarding disc perfusion.

Combined open decompressive laminectomy and vertebroplasty for treatment of thoracolumbar fractures retrospective review of 41 cases

BACKGROUND

Vertebral compression fractures are common, and can occur concomitantly in patients with symptomatic degenerative stenosis. Less commonly, complicated vertebral body fractures may involve retropulsion of bone into the spinal canal, resulting in stenosis with myelopathy and/or radiculopathy. Decompression of the neural elements can lead to destabilization and progressive kyphotic deformity. Laminectomy combined with open vertebroplasty provides a way to decompress the neural elements and stabilize the anterior columns in patients who cannot tolerate extended surgical time or complications associated with instrumentation and fusion. The authors describe the combination of decompressive laminectomy and open transpedicular vertebroplasty as a means to decompress neural elements and simultaneously stabilize the anterior vertebral column.

METHODS

Forty-one patients with a total of 51 thoracolumbar fractures were included in this retrospective case review. A decompressive laminectomy was performed first, followed by vertebroplasty using an open transpedicular approach. For subjective assessment of outcome, the patients were assessed using the Oswestry Low Back Disability Questionnaire and additional questions pertaining to the patient's condition.

RESULTS

Out of 51 fractures, there were 15 burst fractures and 36 compression fractures. Fracture levels ranged from T12 to S1. The average follow-up period was 27 months (range, 0.5-60 months). The mean post-operative Oswestry score was 16 (range, 0-39), and all patients except for one were subjectively pleased with the results of the procedure and said they would recommend it to others. All patients were able to return to all routine activities of daily living.

CONCLUSIONS

The authors' cases indicate combining open decompressive laminectomies with vertebroplasty can be an effective treatment for patients with complicated thoracic and lumbar fractures without involving bone fusion or spinal instrumentation and with good long-term outcomes.

Polyostotic fibrous dysplasia of the thoracic spine: case report and review of the literature

STUDY DESIGN

A case report of polyostotic fibrous dysplasia including thoracic spine, sacral vertebrae, and temporal bone, with the symptom of back pain.

OBJECTIVE

To treat the lesions with percutaneous kyphoplasty.

SUMMARY OF BACKGROUND DATA

Polyostotic fibrous dysplasia involving either spine or temporal bone is rarely seen. Few reports of this disorder appear in the literature. This is the first case including thoracic spine, sacrum, and temporal bone together presented to date.

METHODS

The patient was a 56-year-old woman with polyostotic fibrous dysplasia involving the thoracic spine of the eighth, ninth, and 10th vertebral body; adjacent rib; the right temporal bone and the sacrum. Percutaneous kyphoplasty in ninth and 10th vertebral body was carried out to achieve substantial pain relief and rapid stabilization of the spine with minimal invasion.

RESULTS

The patient experienced complete pain relief and had no clinical complications associated with the cement leakage. The patient tolerated the procedure well. There were no clinical complications and substantial pain relief was noted within hours of the procedure. She has no pain or disability at 1-year follow-up.

CONCLUSION

Percutaneous kyphoplasty was a good therapeutic option for the reported patient.

Percutaneous vertebroplasty for osteoporotic vertebral compression fractures in the nonagenarians: a prospective study evaluating pain reduction and new symptomatic fracture rate

STUDY DESIGN

A prospective observational cohort study of consecutive osteoporotic vertebral compression fractures (VCFs) in ≥ 90-year-old patients evaluated at a multidisciplinary, university spine center.

OBJECTIVE

Assess efficacy, safety, and new fracture occurrence after percutaneous vertebroplasty (PV) in a large uncontrolled cohort of ultra elderly VCF patients.

SUMMARY OF BACKGROUND DATA

VCFs are associated with increased morbidity and mortality. Percutaneous injection of polymethylmethacryl-ate into the fractured vertebral body, vertebroplasty, has been extensively performed as an effective minimally-invasive treatment option for VCF patients. The patient sample included consecutive, osteoporotic patients with symptomatic VCFs electing to enter the study.

METHODS

Baseline visual analogue scale rating, analgesic usage, duration of symptoms. Subsequent VAS ratings, analgesic utilization, and new fractures were assessed within 30 minutes after the procedure, at 2 weeks, 1 month, 3 months, 6 months, 1 year, and 2 years postprocedure.

OUTCOME MEASURES

Visual Analogue Scale score, analgesic utilization, patient satisfaction, cement extravasation, and new fractures. RESULTS.: A total of 123 (74% female) underwent PV for 163 VCFs. Eleven patients did not complete final follow-up at 2 years due to death unrelated to the PV procedure. The mean VAS score was 7.6 at baseline and 3.1 at 30 minutes after the procedure, and 2.3, 1.2, 1.1, 0.9, 0.8, and 0.5 at 2 weeks, 1 month, 3 months, 6 months, 1 year, and 2 years, respectively. Improvement over time was statistically significant using repeated measures analysis of variance (P < 0.05). No complications were encountered during the follow-up intervals. Thirteen new fractures were observed (10.6%) at a mean 20.8 weeks (1-52 weeks) after PV with 6 new fractures (4.9%) involving an adjacent level in 5 patients (4.1%).

CONCLUSION

Vertebroplasty for VCFs in the very elderly appears effective and safe without increased risk of adjacent level fracture.

Management of painful spinal lesions caused by multiple myeloma using percutaneous acrylic cement injection

BACKGROUND AND PURPOSE

Spinal lesions with marked destruction are common site of morbidity in patients with multiple myeloma causing serious clinical symptoms. The aim of the study was to evaluate the therapeutic benefit of percutaneous vertebroplasty (PVP) in treating vertebral body lesions in patients suffering from multiple myeloma.

MATERIALS AND METHODS

Twenty nine patients (55 vertebral bodies) were treated after complete diagnostic evaluation, preparation and obtaining informed consent. Needle position and acrylic material injection was performed under fluoroscopic guidance.

RESULTS

Average visual analogue score dropped from 7.8 before to 2.3 after the intervention. Soft tissue leak was present at 9 treated levels, small epidural cement collection at 5, venous leak at 4 and intradiscal leak at 3 levels without any clinically manifest complications. The effects of PVP were stable in all of the patients at 12 months follow-up. Subjective outcome scores collected through follow-up showed improvement of +1.45 in pain, + 1.15 in ambulation and + 1.23 in medication use. There were recurrence of back pain in 9 patients at non-treated levels due to the new lesions.

CONCLUSION

In our series, PVP of painful lesions caused by multiple myeloma provides immediate and long-term pain relief. The procedure is safe and, despite of the present leakage of cement, may be performed on outpatients basis.

Polymethylmethacrylate-augmented screw fixation for stabilization of the osteoporotic spine : a three-year follow-up of 37 patients

OBJECTIVE

The purpose of this study was to determine the efficacy, radiological findings, clinical outcomes and complications in patients with lumbar stenosis and osteoporosis after the use of polymethylmethacrylate (PMMA) augmentation of a cannulated pedicle screw.

METHODS

Thirty-seven patients with degenerative spinal stenosis and osteoporosis (T-score < -2.5) underwent lumbar fusion using the Dream Technology Pedicle Screw (DTPS, Dream Spine Total Solutions, Dream STS, Seoul, Korea) between 2005 and 2007. The clinical outcomes were evaluated by using the visual analog scale (VAS) and the Prolo scale. Radiologic findings were documented through computed tomography (CT) and plain films.

RESULTS

Thirty-seven patients were evaluated and included, 2 males and 35 females with an average bone mineral density (BMD) of 0.47g/cm(2). The average age of the patients was 68.7 (range, 57-88). The preoperative VAS for low back and leg pain (7.87 +/- 0.95 and 8.82 +/- 0.83) were higher as compared with postoperative VAS (2.30 +/- 1.61 and 1.42 +/- 0.73) with statistical significance (p = 0.006, p = 0.003). According to the Prolo scale, 11, 22, one and three patients were in excellent, good, fair and poor conditions, respectively. The average amount of the injected cement per one cannulated screw was 1.83 +/- 0.11 mL.

CONCLUSION

The results show favorable outcome both clinically and radiographically for 37 patients who underwent lumbar fusion using DTPS and PMMA. Based on the results, the use of this surgical method can be a safe and effective option for the operation on the osteoporotic spine.

Severe thoracolumbar osteoporotic burst fractures: treatment combining open kyphoplasty and short-segment fixation

INTRODUCTION

The majority of osteoporotic, spinal cord compressive, vertebral fractures occurs at the thoracolumbar junction level. When responsible for neurological impairment, these rare lesions require a decompression procedure. We present the results of a new option to treat these lesions: an open balloon kyphoplasty associated with a short-segment posterior internal fixation.

MATERIALS AND METHODS

Twelve patients, aged a mean 72.3 years, were included in this prospective series; all of them presented osteoporotic burst fractures located between T11 and L2 associated with neurological impairment. The surgical procedure first consisted of a laminectomy, for decompression, followed by an open balloon kyphoplasty. A short-segment posterior internal fixation was subsequently put into place when the local kyphosis was considered severe. A CAT scan study evaluated local vertebral body's height restoration using two pre- and postoperative radiological indices.

RESULTS

All of the patients in the series were followed up for a mean 14 months. Local kyphosis improved a mean 10.8 (p<0.001). Vertebral body height was also substantially restored, with a mean gain of 26% according to the anterior height/adjacent height ratio and 28% according to the Beck Index (p<0.001). Two cases of cement leakage were recorded, with no adverse clinical side effect. Complete neurological recovery was observed in 10 patients; two retained a minimal neurological deficit but kept a walking capacity.

DISCUSSION

The results presented in this study confirm the data reported in the literature in terms of local kyphosis correction and vertebral body height restoration. The combination of this technique with laminectomy plus osteosynthesis allowed us to effectively treat burst fractures of the thoracolumbar junction and led to stable results 1 year after surgery. This can be advantageous in a population often carrying multiple co-morbidities. With a single operation, we can achieve neurological decompression and spinal column stability in a minimally invasive way; this avoids more substantial surgery in these fragile patients.

LEVEL OF EVIDENCE

Level IV. Therapeutic prospective study.

OPEN KYPHOPLASTY FOR MANAGEMENT OF SEVERE OSTEOPOROTIC SPINAL FRACTURES

OBJECTIVE

Osteoporotic compression fractures, which can lead to neurological complications in some cases, are an increasingly frequent occurrence. These lesions require decompression surgery with or without spinal stabilization procedures. In this article, we present the preliminary results obtained using open kyphoplasty, a new method of treating vertebral compression disorders.

METHODS

Sixteen patients were included in this prospective study, and a total of 17 vertebrae were treated. All of the patients had vertebral compression fractures associated with neurological disorders. The surgical treatment consisted of open kyphoplasty after laminectomy and decompression. Short-segment vertebral osteosynthesis was also performed in patients with pronounced local kyphosis. Pain was rated at clinical assessments, and radiological assessments were performed to determine the restored vertebral height and the correction of any local vertebral kyphosis.

RESULTS

Analysis of the results obtained using this method showed that vertebral height was significantly improved (P &lt; 0.001) and local kyphosis was significantly reduced (P &lt; 0.001). The mean operating time was 90 minutes. The neurological status of all patients improved; 14 patients recovered completely from their neurological symptoms. The last 2 patients had associated neurological disease but were able to walk. There were 2 superficial postoperative infections.

CONCLUSION

This method for treating severe osteoporotic compression fractures associated with neurological disorders gives successful results and can be used to treat neurological compression fractures while consolidating the vertebral body. Therefore, this less invasive approach seems to be particularly useful for treating compression fractures in the thoracolumbar spine junction in elderly patients who often have comorbidities.

Long-term evaluation of a calcium phosphate bone cement with carboxymethyl cellulose in a vertebral defect model

We investigated histological and compressive properties of a calcium phosphate bone cement (BoneSource (CPC); Stryker Orthopaedics, Mahwah, New Jersey) plus carboxymethyl cellulose (CMC) using a sheep vertebral bone void model. Bone voids were surgically created in L3 and L5 in each of 40 sheep, and the voids were filled with the cement. Histological and radiographic evaluations were performed on one vertebral body from each animal at either: 0, 3, 6, 12, 24, or 36 months after surgery; mechanical testing was performed on operated and non-operated vertebral bodies from 35 sheep. Undecalcified sections were digitized, and the area of the original defect, new bone formation, empty space, fibrous tissue, and residual cement were quantified with histomorphometry. Decalcified sections were evaluated qualitatively. The cement was biocompatible, extremely osteoconductive and underwent steady resorption and replacement by bone and bone marrow. Histomorphometry showed variations in the rate of cement remodeling among animals in each time group, but on average, at 36 months the original defect area was occupied by approximately 14% bone, 82% cement, and 4% bone marrow. Even in animals that had greater resorption of cement, there was good bone ingrowth with no fibrous tissue. Compressive testing did not reveal a significant difference in the mechanical properties between vertebral bodies augmented with cement and non-augmented controls, irrespective of the postoperative time. BoneSource mixed with CMC had adequate osteoconductivity, biocompatibility, and adequate compressive strength. There was variability among animals, but histology suggests that considerable cement was still present in most samples after 36 months.

Vertebroplasty as treatment of aggressive and symptomatic vertebral hemangiomas: up to 4 years of follow-up

INTRODUCTION

This study aimed to illustrate the validity of the treatment with vertebroplasty (VP) in patients with aggressive or symptomatic vertebral hemangioma (VH) with or without epidural extension.

METHODS

From January 2003 to December 2007, 24 consecutive patients have been treated with VP, for a total of 36 vertebral bodies affected by VH: two cervical, ten dorsal, 24 lumbar. All the patients complained of a pain syndrome resistant to continuous medical medication; four of 24 patients also presented aggressive magnetic resonance features of the vertebral lesion and two patients showed also epidural extension. A unipedicular approach has been performed in 16 patients; a bipedicular approach has been performed in six, while for the cervical spine an anterior-lateral approach with manual dislocation of the carotid axis has always been performed. Bone biopsy was never done. All procedures have been carried out with local anesthesia, except for the treatment of the cervical hemangiomas which has always been performed under general anesthesia. Four vertebral bodies in the same session have been treated in one case.

RESULTS

Results have been evaluated with the visual analog scale and the Oswestry Disability Index methods. In all the patients, in the following 24-72 h, a successful outcome has been observed with a complete resolution of pain symptom. Extravertebral vascular or discal cement leakage has been observed in four patients, without any onset of clinical radicular syndrome due to epidural diffusion. Clinical and radiological follow-up until 4 years has been performed in 12 patients and it showed stability of the treatment and absence of pain.

CONCLUSIONS

Percutaneous treatment with VP for aggressive and symptomatic vertebral hemangiomas even with epidural extension is a valuable, mini-invasive, and quick method that allows a complete and enduring resolution of the painful vertebral symptoms without findings of fracture of a vertebral body adjacent or distant to the one treated.

Vertebroplasty and kyphoplasty: friends or foes?

PURPOSE

This paper aims to compare vertebroplasty and kyphoplasty by illustrating the two techniques, analysing the results and discussing the indications in relation to the type of fracture.

MATERIALS AND METHODS

Vertebroplasty was performed on 805 vertebral bodies in 485 patients affected by osteoporosis (310), metastasis (160) and vertebral haemangioma (15). The approach was unipedicular in 365 patients and bipedicular in 120 patients. Biopsies were obtained in patients with no known primary cancer (75). Kyphoplasty was performed in 39 patients with Magerl type A1 and A3 fractures within 3 months from the trauma. A bipedicular approach was used in all cases.

RESULTS

Outcomes were assessed on the basis of the visual analogue scale and the Oswestry Disability Index. In patients treated with vertebroplasty, success rates at 24-72 h were 90% for osteoporotic fractures, 100% for vertebral haemangiomas and 77% for metastatic fractures. Extravertebral vascular or discal leakage of cement occurred in 39 patients, but only two of them reported radicular pain due to epidural involvement. Osteoporotic patients developed new vertebral fractures at adjacent levels in 25 cases and at distal levels in 19 cases. In patients treated with kyphoplasty, pain relief was achieved within one month after treatment in 90% of cases. None of the patients wore orthotic braces after treatment, and no vertebral collapse was observed.

CONCLUSIONS

Vertebroplasty and kyphoplasty are both useful in the management of vertebral pain. In light of our experience, vertebroplasty is better indicated for vertebral fractures due to osteoporosis, haemangioma or metastasis on account of its simplicity and minimal invasiveness. Kyphoplasty is suggested in acute traumatic fractures of type A1 and A3 according to Magerl, as it allows recovery of vertebral stability and a better distribution of the cement.

The Patterns of Intraosseous Venography before Percutaneous Vertebroplasty for Osteoporotic Compression Fractures

OBJECTIVE

Bone cement leakage is a well-known potential complication of percutaneous vertebroplasty (PVP) in patients with osteoporotic compression fracture. Even though there has been a controversy in the efficacy of antecedent venography to prevent this complication, many authors have performed intraosseous venography before bone cement injection. The goal of this study was to classify the venous drainage patterns of spine before PVP, and compare their patterns at different vertebral levels.

METHODS

The authors retrospectively reviewed 1,042 intraosseous venographic patterns in 321 patients with 574 osteoporotic compression fractures during six-year period in one institution. To classify venogram patterns, we selected simple lateral X-ray of spine taken immediately after injection of the contrast dye. We classified the venography patterns according to contrast leakage pattern and leakage direction as follows; trabecular (TR), trabecular anterior (TA), trabecular posterior (TP), trabecular anterior-posterior (TAP), trabecular lateral (TL), venous anterior(VA), venous posterior (VP), venous anterior-posterior (VAP), soft tissue (ST). Also, we compared venogram patterns according to different spinal levels.

RESULTS

In overall, the most common pattern was TP type accounting for 37.4% (390/1042) of all intraosseous venograms. This is followed by TAP in 21.5%, TR 17.4%, TA 11.6%, TL 5.8%, ST 4.1%, VA 1.2%, VP 0.6%, and VAP 0.4% in descending order of frequency. According to the spinal level, TR and TAP types were most common in thoracic spine (T6-T10), TP type was most common in thoraco-lumbar spine (T11-L2), and TP and TAP types were most common in lumbo-sacral spine (L3-S1). Contrast dye leakage to soft tissue such as psoas muscle or disc were detected in 43 (4.1%) venograms. Direct venous drainage without staining of vertebral body was found in 23 (2.2%) venograms. The 8.3% of thoracic venogram showed direct venous drainage. Thoracic level showed a more tendency of direct venous drainage than other spine levels (p<0.01).

CONCLUSION

The authors propose a new classification system of intraosseous venography during PVP. The trabecular-posterior (TP) type is most common through all spine, and venous-filling (V) type was most frequent in thoracic spine. Further study would be necessary to elucidate the efficacy of this classification system to prevent bone cement leakage during PVP.

Segmental polymethylmethacrylate-augmented pedicle screw fixation in patients with bone softening caused by osteoporosis and metastatic tumor involvement: a clinical evaluation

OBJECTIVE

Instrumentation of the osteoporotic spine may result in bone failure because of pedicle screw loosening and pullout. A clinical evaluation of a novel fenestrated bone tap used in pedicle screw augmentation was performed to determine the performance and safety of this technique.

METHODS

Over a 2.5-year period, the clinical and radiographic results of 119 consecutive patients who underwent instrumented arthrodesis were reviewed. Of these patients, 23 had bone softening secondary to osteoporosis and/or metastatic spinal tumor involvement. These patients underwent surgical decompression and spinal instrumentation.

RESULTS

Six patients (26%) had metastatic spine disease (squamous cell lung carcinoma, renal cell carcinoma, bladder carcinoma, breast, prostate, and uterine adenocarcinoma); five patients (22%) had a degenerative spondylolisthesis; and 12 patients (52%) had burst fractures, eight as a result of benign causes and four as a result of metastatic disease. Four (17%) patients underwent revision surgery of previous pedicle screw failure resulting from bone softening and pseudarthrosis. A total of 98 levels were fused using 158 polymethylmethacrylate-augmented screws. None of the patients experienced operative death, myocardial infarction, hypoxemia, intraoperative hypotension, radiculopathy, or myelopathy. Asymptomatic anterior cement extravasation was observed in nine patients (39%). There was one asymptomatic polymethylmethacrylate pulmonary embolus and one wound infection. There was no significant relationship between cement extravasation and the quantity used, levels augmented, or location (P > 0.05). There were no construct failures.

CONCLUSION

Polymethylmethacrylate-augmented pedicle screw fixation reduces the likelihood of pedicle screw loosening and pullout in patients with osteoporosis requiring instrumented arthrodesis.

Cement leakage into the posterior spinal canal during balloon kyphoplasty: a case report

We report a case of cement leakage into the posterior spinal canal due to inadvertent pedicle perforation during balloon kyphoplasty. The leakage was corrected immediately without any sequelae. Features seen on radiography and the minimally invasive procedure used for removal are described. The postoperative radiographs of 100 consecutive patients treated with balloon kyphoplasty were subsequently reviewed. Only one patient had a similar leakage but had no neurological complications.

A biomechanical cadaveric analysis of polymethylmethacrylate-augmented pedicle screw fixation

Object

Instrumentation of the osteoporotic spine can be fraught with complications such as hardware failure. A cadaver study was performed to determine the biomechanical performance of polymethylmethacrylate (PMMA)–augmented pedicle screws.

Methods

Three osteoporotic human cadaveric specimens with a mean bone mineral density of 0.70 g/cm2 were used to evaluate the performance of a novel fenestrated bone tap in pedicle screw augmentation. On this device, tap threads serve a dual purpose in preventing backflow of cement toward neural elements while allowing for a custom form for subsequent screw placement. The tap was used to inject a mean volume of 3.7 ml PMMA/pedicle (range 2–8.0 ml PMMA/pedicle) followed by pedicle screw placement between L-5 and T-5, alternating between augmented and nonaugmented instrumentation. Axial pullout testing was then performed.

Results

Pedicle screw pullout strength was increased in both primary and salvage procedures by 119% (p = 0.001) and 162% (p = 0.01), respectively, after PMMA augmentation. Additionally, the injected cement volumes were divided into two groups, a low-cement group (≤ 2.8 ml/pedicle) and a high-cement group (≥ 5.5 ml/pedicle). Interestingly, the pullout strength did not significantly change with increased cement usage between the two groups (p > 0.05 for all comparisons).

Conclusions

Polymethylmethacrylate-augmented pedicle screw fixation results in a significant increase in the axial pullout strength of augmented pedicle screws in both primary and revision procedures. This technique may be a valuable adjunct in cases in which bolstering of the screw–bone interface is necessary.

Traitement par kyphoplastie à foyer ouvert des métastases rachidiennes

INTRODUCTION

Metastatic spine fractures are very frequent, often occurring in patients with severe medical conditions. Open kyphoplasty and vertebroplasty are part of the classic management of this of fracture. In certain conditions such as spinal cord compression caused by epidural metastatic cancer or collapse of the vertebral body implying a local kyphosis, surgery should allow decompression of the spinal cord and stabilisation of the spine in a simple act. The purpose of this study is to assess a surgical technique combining surgical decompression by laminectomy frequently associated with posterior transpedicular instrumentation and at the same time, an open kyphoplasty to stabilize the anterior part of the spine.

MATERIAL AND METHODS

The same procedure was performed in 14 patients during an 18-month period. The average age of the patients was 54 years. All patients suffered severe pain before the surgical procedure (VSA mean: 7). Neurological deficiency was noted in 10 of the 14 patients with this spinal cord compression. Nineteen vertebrae were treated; a short posterior instrumentation was necessary in 11 patients. The average operative time was 90 minutes. Of the patients with neurological deficiency, the clinical status improved after surgery in all. The average VSA of this series 3 days after surgery was 2. The mean quantity of PMMA injected was 7 cc. Two PMMA leaks, one in the intervertebral disc and one forward, were identified on the postoperative CT scan. The average hospital stay was 7 days.

CONCLUSION

This procedure enables surgical decompression, vertebral body consolidation and consequently spinal stabilization of the spine. We did not have any complications related to this procedure which, particularly for the elderly population, is an attractive alternative to major surgery such as vertebrectomy.

Combined extraforaminal and intradiscal cement leakage following percutaneous vertebroplasty

STUDY DESIGN

A case report and review of the literature are presented.

OBJECTIVE

To describe an extremely rare case of combined extraforaminal and intradiscal cement leakage in different vertebral levels following percutaneous vertebroplasty.

SUMMARY OF BACKGROUND DATA

Cement leaks in vertebroplasty are relatively common but generally not clinically significant. To our knowledge, this is the first report of extraforaminal cement leakage inducing radiculopathy combined with intradiscal cement leakage evoking acute adjacent compression fracture.

METHODS

A 78-year-old woman with L2 and L5 osteoporotic compression fractures received vertebroplasty. Two weeks after surgery, the patient presented severe low back pain radiating to the right thigh, with associated weakness and numbness in the right thigh and lower leg. Roentgenographic images revealed cement leakage into the right extraforamen of L2-L3 as well as leakage into L4-L5 disc with acute adjacent compression fracture of L4.

RESULTS

Surgical intervention was required to relieve discomfort. One-stage posterior approach was performed: right L2-L3 intertransverse process approach with removal of extraforaminal leaked cement and posterior instrumentation from L3-L5 and posterior fusion. The severe low back pain, leg pain, and neurologic deficit associated weakness all improved after surgery.

CONCLUSION

Although considered a minimally invasive procedure, percutaneous vertebroplasty with polymethylmethacrylate is not risk free. Intractable neurologic complications can occur if it is not performed by experienced physicians under appropriate indications and cautionary safeguards.

Open kyphoplasty for management of metastatic and severe osteoporotic spinal fracture

Object

Elderly patients in poor general health frequently suffer vertebral body (VB) fractures due to osteoporosis or vertebral metastatic lesions. Kyphoplasty and vertebroplasty have become the standard treatment for these types of fractures. In certain conditions that cause local kyphosis, such as spinal cord compression due to a metastatic epidural tumor or the shortening of the spinal canal secondary to vertebral compression, the surgical treatment should provide decompression and stabilization during a short intervention. In this study the authors evaluated a surgical technique that frequently combines a same-session surgical decompression, such as a laminectomy, and posterior instrumentation-assisted stabilization during the same open intervention in which the VB is stabilized by kyphoplasty.

Methods

During an 18-month period, the authors treated 18 patients with VB fractures according to this protocol: 14 patients with vertebral metastatic lesions and four with osteoporosis. The patients' mean age was 60 years. All suffered severe pain preoperatively (mean visual analog scale [VAS] score of 7). Fourteen of the 18 patients suffered a neurological deficit. Twenty-three vertebral levels were treated; in 15 patients it was necessary to place posterior instrumentation. The mean duration of the intervention was 90 minutes.

Pain in all patients improved 3 days after the intervention, and the mean VAS score decreased to 2. Patients with a neurological dysfunction improved. The mean quantity of injected cement for the kyphoplasty procedure was 7 ml. The mean duration of hospitalization was 7 days. Neuroimaging revealed cement leaks in two cases: one into the disc interspace and one anteriorly into the fractured part of the vertebra. After the intervention, most patients with metastatic lesions underwent radiotherapy. No procedure-related complications occurred.

Conclusions

This procedure allows decompression of the spinal cord, consolidation of the VB and thus a stabilization of the vertebral column, and may provide an alternative treatment to invasive VB excision in patients in poor general health.

Rapid and reliable biomechanical screening of injectable bone cements for autonomous augmentation of osteoporotic vertebral bodies: Appropriate values of elastic constants for finite element models

We performed finite element analysis studies on 3 three-dimensional representations of a single vertebral body: a regular cube, made of low-density polyurethane foam (foam cube analog); a regular cube considered composed of cancellous bone only (bone cube analog)); and the body of the L2 vertebra (full anatomical body model). Each finite element model was subjected to a compressive load of 2300 N, uniformly distributed over its superior surface. The cancellous and cortical bones were assigned anisotropic elastic properties, while the foam and the endplate material were considered to have isotropic properties. In each representation, the elastic properties of the material(s) were adjusted (from the initial values that were used) to give a stiffness of the representation that was equal to that of the mean result for fresh cadaveric osteoporotic single vertebral bodies, as obtained from ex vivo experimental studies reported in the literature (1226 +/- 996 N mm(-1)). Thus, any one of these representations, when used with the final adjusted value(s) of the elastic constants and modified to include a cylindrical hole filled with a specific volume of bolus of an injected bone cement, may be utilized in the rapid and reliable experimental ex vivo and/or numerical screening of these cements for use in autonomous vertebral body augmentation. This approach has many advantages over those that are currently being used, which are either characterization of the cement in isolation from the vertebral body or use of cadaveric vertebral bodies.

Surgical removal of extravasated epidural and neuroforaminal polymethylmethacrylate after percutaneous vertebroplasty in the thoracic spine

Although extravasations of polymethylmetharylate during percutaneous vertebroplasty are usually of little clinical consequence, surgical decompression is occasionally required if resultant neurologic deficits are severe. Surgical removal of epidural polymethylmetharylate is usually necessary to achieve good neurologic recovery. Because mobilizing the squeezed spinal cord in a compromised canal can cause further deterioration, attempts to remove epidural polymethylmetharylate in the thoracic region need special consideration. A 66-year-old man had incomplete paraparesis and radicular pain on the chest wall after percutaneous vertebroplasty for osteoporotic compression fracture of T7. Radiological studies revealed polymethylmetharylate extravasations into the right lateral aspect of spinal canal that caused marked encroachment of the thecal sac and right neuroforamina. Progressive neurologic deficit and poor responses to medical managements were observed; therefore, surgical decompression was performed 4 months later. After laminectomy and removal of facet joints and T7 pedicle on the affected side, extravasated polymethylmetharylate posterior and anterior to the thecal sac was completely removed without retracting the dura mater. Spinal stability was reconstructed by supplemental spinal instrumentation and intertransverse arthrodesis with banked cancellous allografts. Myelopathy and radicular pain gradually resolved after decompression surgery. The patient was free of sensory abnormality and regained satisfactory ambulation two years after surgical decompression.

Intradural cement leakage: a devastatingly rare complication of vertebroplasty

STUDY DESIGN

The aim of this case report is to examine the devastating complication that may follow vertebroplasty.

OBJECTIVES

To report 1 case of intradural cement leakage caused by percutaneous vertebroplasty with polymethyl methacrylate.

SUMMARY OF BACKGROUND DATA

Cement leakage is not a rare complication of vertebroplasty. But intradural cement leakage is rare. We herein report a rare but devastating complication of vertebroplasty.

METHODS

A 90-year-old woman with a T12 and L1 osteoporotic compression fracture underwent percutaneous vertebroplasty using polymethyl methacrylate at local hospital. A literature search was performed to assess complications of vertebroplasty.

RESULTS

She was transferred to our hospital due to abdominal pain. Physical examination revealed distended abdomen with local tenderness and weakness of both legs (muscle power: Grade 2). Plain radiograph of abdomen showed ileus and intradural cement leakage. Conservative treatment with nasogastric decompression was done, and her abdominal pain subsided 1 week later.

CONCLUSIONS

Percutaneous vertebroplasty with polymethyl methacrylate is relatively safe, but it still should be proceeded under careful safeguard. The needle tip should not cross the medial border of the pedicle on the anteroposterior view before it has crossed the posterior cortex of the vertebral body on the lateral view. Good quality of image monitoring and clear visualization of cement should be helpful to prevent complications.

Cement leakage in percutaneous vertebroplasty: effect of preinjection gelfoam embolization

STUDY DESIGN

Prospective case series.

OBJECTIVES

To determine the safety and feasibility of routine preinjection of gelfoam embolization during percutaneous vertebroplasty.

SUMMARY OF BACKGROUND DATA

Percutaneous vertebroplasty has been used effectively in pain relief for vertebral fractures resulting from malignancy and osteoporosis. However, cement extrusion is a common problem and can lead to complications. Gelfoam embolization of venous channels before cement injection has not been widely used as a technique to prevent leakage.

METHODS

Thirty-one patients who met the inclusion-exclusion criteria for the study underwent percutaneous vertebroplasty. Venography was first performed to determine the flow pattern in the vertebrae and confirm needle placement. Next, routine gelfoam embolization of venous channels was performed. This was followed by low-pressure, minimal-volume cement injection. The outcome measure of cement leakage was assessed after surgery using radiographs and CT scans.

RESULTS

There were no complications. In the 31 patients, 61 levels of vertebroplasty were performed. Overall, there were 16 leaks out of 61 levels in 12 patients (26.2%). In osteoporotic fractures, there were 11 leaks in 49 levels, giving a leakage rate of 22.5%. There was only 1 epidural leak in this group (2%), and this was asymptomatic. Seven leakages were into the adjacent disc, 2 into the body, and 1 into the paravertebral tissues. In malignant fractures, there were 5 leakages out of 12 levels (41.7%). Of these, 2 were epidural leaks (16.7%), which were asymptomatic.

CONCLUSIONS

Complications resulting from leakage are the most feared side effect of the procedure. This has resulted in only limited application of vertebroplasty in the United Kingdom. Routine gelfoam embolization together with careful technique has been shown to be a safe and feasible method during vertebroplasty.

In vitro investigation of heat transfer in calf spinal cord during polymethylmethacrylate application for vertebral body reconstruction

The objective of this experimental study was to investigate the temperature variations within the spinal cord of calf cadavers during polymethlymethacrylate (PMMA) application for vertebral body reconstruction. Cervical spines including the cervical spinal cord of ten fresh cadavers were used. Corpectomy and laminectomy were performed and dura was exposed at the same level for proper placement of thermal sensors. Sensors were placed in multiple holes in the spinal cord at depths of 3, 6, 9 and 12 mm, respectively. Whether the thermal sensors were placed in the gray or white matter was determined by computerized tomography. The white and gray matters of the spinal cord exhibited different thermal properties. The white matter was more conductive and absorbed less heat than the gray matter. The heat sensor nearest to PMMA exhibited temperatures of 42-44 degrees C. The second heat sensor placed at 9 mm depth within the gray matter showed 44 degrees C. The third sensor, which was placed at 6 mm depth within the spinal cord recorded the same temperature as the first, i.e., nearest to PMMA sensor. The fourth heat sensor, which was at the farthest location from PMMA demonstrated 37-39 degrees C. The temperature distribution within the gray matter was inversely proportional to the distance from the heat source. The temperature at the dorsal white matter, which was distant from the heating source, remained nearly constant and was not elevated. Our data suggest that thermal injury to the spinal cord during PMMA application may be expected to be more significant in the gray matter when compared with other neural tissues.

Anterior spinal column augmentation with injectable bone cements

A vertebral fracture, whether originating from osteoporosis or trauma, can be the cause of pain, disability, deformation and neurological deficit. The treatment of vertebral compression fractures has, for many years until the advent of vertebroplasty, consisted of bedrest and analgesics. Vertebroplasty is a percutaneous technique during which bone cement is injected in a vertebral body to provide immediate pain relief by stabilization. Inflatable bone tamps can, prior to the injection of cement, be used to create a void in the vertebral body, in which case the technique is known as balloon vertebroplasty (or kyphoplasty). The chance of extracorporal cement leakage is smaller for balloon vertebroplasty than for vertebroplasty. Some authors also claim to have gained some correction in vertebral body height or angulation. Both interventions can be used for several indications, including osteoporotic compression fractures and osteolytic lesions of the vertebral body such as myeloma, hemangioma or metastasis, and also for traumatic burst fractures in combination with pedicle screw instrumentation. Polymethyl methacrylate cement is the bone void filler that is used most frequently, although the application of calcium phosphate cements has been studied widely in vitro, in vivo and also in small-scale clinical series. The clinical results of (balloon-) vertebroplasty are favorable with 85-95% of all patients experiencing immediate and long-lasting relief of pain. Serious complications are relatively rare but include neurological deficit and pulmonary embolism. In this paper, both vertebroplasty and balloon vertebroplasty and their respective indications, techniques and results are described in relation with the application and limitations of permanent and resorbable injectable bone cements.

Bone displacement and the role of longitudinal ligaments during balloon vertebroplasty in traumatic thoracolumbar fractures

STUDY DESIGN

In a human cadaveric burst fracture model with and without longitudinal ligament damage, the amount of anterior and posterior bone displacement (ABD, PBD) during balloon vertebroplasty after pedicle-screw instrumentation was investigated quantitatively.

OBJECTIVES

To investigate, in a burst fracture model with and without longitudinal ligament damage, the amount of ABD, PBD, and cement leakage at various phases during balloon vertebroplasty in combination with pedicle-screw instrumentation.

SUMMARY OF BACKGROUND DATA

The role of intact longitudinal ligaments in traumatic spine fractures, for prevention of bone retropulsion and subsequent reduction, has been discussed in several studies but is still up for debate. In a recent human cadaveric burst fracture study, inflatable bone tamps and calcium phosphate cement were used for the augmentation of the anterior column after pedicle-screw instrumentation. The additional balloon vertebroplasty procedure was found to be feasible and safe, but no data pertaining to unwarranted bone displacement or cement leakage during the procedure are available for burst fractures with damaged longitudinal ligaments.

METHODS

Ten thoracic and 10 lumbar burst fractures, with rotation or flexion components, were created, and balloon vertebroplasty with calcium phosphate cement was performed after pedicle-screw instrumentation. Volumetric datasets (using the 3-dimensional (3D) rotational x-ray imaging technique) of the fractures were obtained during the following phases: intact, fractured, after reduction and stabilization with pedicle-screws, after inflation of the balloons, after deflation and removal of the balloons, and after injection of the cement. The amount of ABD and PBD was measured on reconstructed sagittal images and recorded together with the presence of extracorporal cement leakage. The continuity of the longitudinal ligaments was assessed after anatomic dissection.

RESULTS

During the balloon vertebroplasty procedure, a significant (P < 0.05) increase of ABD (at both thoracic and lumbar level) and PBD (thoracic level) occurred after inflation of the balloons. After deflation and subsequent injection of the cement, however, the ABD and PBD returned to the preinflation levels. The absolute amount of ABD and PBD (<1 mm) during inflation was considered of little clinical importance. No differences in ABD or PBD were observed for specimens with or without continuity of the corresponding longitudinal ligament, irrespective of the level, at any of the phases during the experiment (P > 0.5 in all cases). A small amount of cement leakage was observed in the psoas compartment of one specimen with intact longitudinal ligaments.

CONCLUSIONS

It is suggested that balloon vertebroplasty after pedicle-screw instrumentation may safely be used, in terms of bone displacement and cement leakage, in fracture types where damage to longitudinal ligaments is to be expected.

Spondylitis following vertebroplasty: a case report

PURPOSE

Spondylitis is a rare complication of vertebroplasty with only one case report having been published to date. We report a further case of spondylitis after vertebroplasty that was managed successfully with conservative therapy.

METHODS

The clinical course of a 55-year-old patient with secondary osteoporosis due to liver cirrhosis from alcohol abuse is reported, in whom percutaneous vertebroplasty of three fractured vertebral bodies (L3-L5) was complicated by spondylitis at these levels.

RESULTS

Spondylitis of L3-L5 with paravertebral abscess formation and progressive collapse of L5 was detected by magnetic resonance imaging (MRI). Treatment consisted of percutaneous aspiration of the paravertebral abscess and antibiotic therapy. No bacteria was identified despite cultures have been taken before antibiotic treatment. The patient was treated with intravenous ciprofloxacin and consecutive clindamycin for a total of 3 months. One year after the infection the MRI signs of spondylitis have resolved without further collapse of L5. Painlevels have improved significantly, allowing the patient to return to work, but are still higher than immediately after vertebroplasty.

CONCLUSION

Spondylitis is a rare complication of vertebroplasty. In the presented case a satisfactory result could be achieved through conservative antibiotic therapy and restriction of movement.

A novel percutaneous system for bone graft delivery and containment for elevation and stabilization of vertebral compression fractures. Technical note

OBJECT

Vertebroplasty and kyphoplasty are minimally invasive procedures used to treat persistently symptomatic vertebral compression fractures (VCFs). Both interventions usually involve injection of polymethyl methacrylate (PMMA). The purpose of this technical note was to review the theory and surgical technique for a novel percutaneous system for fracture reduction and stabilization of VCFs by using bone graft.

METHODS

This technical note highlights the Optimesh system as an alternative method of minimally invasive VCF reduction and stabilization with the delivery of a bone graft containment device. Instead of using PMMA as in vertebroplasty or kyphoplasty, this system allows the delivery of allograft and/or autograft bone, with its osteoinductive, osteoconductive, and osteogenic properties.

CONCLUSIONS

This system allows for restoration of sagittal alignment of the spine with direct control of bone graft delivery by using a mesh graft containment device that allows for ingrowth of new bone and vascular tissue.

Cement leakage during vertebroplasty: an underestimated problem?

Overall, vertebroplasty has a low complication rate. Nevertheless, severe complications can occur. The majority of these are related to cement extrusion. The rate of cement leakage is often obtained by X-ray, with only a single leak registration per vertebra. Detection rate of leaks in comparison with CT and inter-observer reliability for X-ray is, in large parts, unknown. We conducted this study to determine the value of fluoroscopy and X-ray used to detect cement leakage as compared to CT scans. Intraoperative findings in lateral fluoroscopy by the surgeon, and postoperative findings in X-rays by two orthopaedic surgeons, were compared with CT scans for the same study group. Multiple cement leakage was considered, and agreement rate was determined. The detection rate for leaks was 34% for lateral X-ray and 48% for lateral and AP view. Additional AP views only enhanced the detection of leaks in the segmental veins. The agreement rate between fluoroscopy/X-ray and CT scans ranged between 66% and 74%, while inter-observer reliability showed only fair agreement. The rate of cement leaks in vertebroplasty is high if multiple leaks are considered in CT scans. Detection rates using X-rays are low and complicated by only fair inter-observer agreement. Leaks in the basivertebral veins are frequently misinterpreted and can lead to severe complications. Therefore, CT scans should be obtained to calculate the exact leakage rate and to assess persistent or new pain occurring postoperatively.

Predictors of outcomes of percutaneous vertebroplasty for osteoporotic vertebral fractures

STUDY DESIGN

Retrospective review of all percutaneous vertebroplasties performed in the authors' institution from November 1994 to June 2002. OBJECTIVE.: To determine the factors affecting the outcome of percutaneous vertebroplasty for the treatment of persistent painful osteoporotic fractures.

SUMMARY OF BACKGROUND DATA

Percutaneous vertebroplasty is an efficient procedure to treat pain due to osteoporotic vertebral fracture. However, the patient population that is most likely to benefit from this procedure is uncertain, and the inclusion and exclusion criteria for an ideal candidate have varied widely in the literature.

METHODS

A retrospective review of 278 percutaneous vertebroplasty procedures for osteoporotic fractures at 423 levels was performed. Sociodemographic, clinical, radiologic, and procedural data were analyzed as parameters for prognosis significance by univariate and multivariate analysis with logistic regression to estimate the strength of influence of each variable.

RESULTS

The presence of two or less symptomatic vertebrae (P < 0.03), the American Society of Anesthesiologists status I (P < 0.001), the presence of signal changes on magnetic resonance imaging (P < 0001), and the collapse of the vertebral body less than 70% (P < 0.001) were assessed as parameters for prognostic significance. Multivariate analysis also showed a significant correlation between the American Society of Anesthesiologists score and height loss of the vertebral body and the final outcome. The presence of signal changes on magnetic resonance imaging showed the highest odds ratio adjusted.

CONCLUSIONS

Appropriate patient selection is essential for achieving clinical success. Better results can be expected in patients with an American Society of Anesthesiologists score of I and when the level managed is confirmed by magnetic resonance imaging and the vertebral body height loss is less than 70%.

Anatomical and pathological considerations in percutaneous vertebroplasty and kyphoplasty: a reappraisal of the vertebral venous system

OBJECTIVES

To focus attention of the clinician on the anatomy and (patho)physiology of the vertebral venous system, so as to offer a tool to better understand and anticipate (potential) complications that are related to the application of percutaneous vertebroplasty and kyphoplasty.

BACKGROUND

Percutaneous vertebroplasty and kyphoplasty are newly developed, minimally invasive techniques for the relief of pain and for the strengthening of bone in vertebral body lesions. With the clinical implementation of these techniques, a number of serious neurologic and cardiopulmonary complications have been reported in the international medical literature. Most complications appear to be related to the extrusion of bone cement into the vertebral venous system.

METHODS

The literature about complications of percutaneous vertebroplasty and kyphoplasty is reviewed, and the anatomic and (patho)physiologic characteristics of the vertebral venous system are reported. Based on what is currently known from the anatomy and physiology of the vertebral venous system, the procedures of percutaneous vertebroplasty and kyphoplasty are analyzed, and suggestions are made to improve the safety of these techniques.

CONCLUSIONS

Thorough knowledge of the anatomic and (patho)physiologic characteristics of the vertebral venous system is mandatory for all physicians that participate in percutaneous vertebroplasty and kyphoplasty. To reduce the risk of cement extrusion into the vertebral venous system during injection, vertebral venous pressure should be increased during surgery. This can be achieved by operating the patient in the prone position and by raising intrathoracic venous pressure with the aid of the anesthesiologist during intravertebral instrumentation and cement injection. Intensive theoretical and practical training, critical patient selection, and careful monitoring of the procedures, also taking into account patient positioning and intrathoracic and intra-abdominal pressures, will help to facilitate low morbidity outcomes in these very promising minimally invasive techniques.

Vertebroplasty for the treatment of osteoporotic compression spinal fracture: comparison of remedial action at different stages of injury

BACKGROUND

Outstanding results have been achieved using vertebroplasty for the treatment of osteoporotic compression spinal fractures, and a number of studies have reported the results from the application of this procedure. This study compared the results of vertebroplasty used at the different stages of injury.

METHODS

A retrospective study reviewing the period between January 2001 and July 2001 investigated 68 patients who underwent single-level vertebroplasty: 22 patients within 2 weeks of the injury, 22 patients 2 weeks to 2 months after the injury, and 24 patients more than 2 months after the injury. Clinical evaluations compared the results of treatment at different injury stages during a mean follow-up period of 13 months.

RESULTS

Although all the patients undergoing vertebroplasty in the acute and subacute stages reported satisfaction within 1 week of the operation, only 72.7% of the acute-stage group reported satisfaction with 24 hours of surgery. Moreover, evidence of cement leakage after vertebroplasty was detected for 27.3% of the acute-stage patients. This percentage significantly higher than for the patients in the subacute and chronic stages. Radiographic examination showed that new, adjacent compression fracture had occurred for 10.3% of the patients, with anterior interbody restabilization occurring for 11.8%.

CONCLUSIONS

The results for vertebroplasty treatment of osteoporotic compression fractures appear to be injury stage dependent, with patients in the acute-injury stage needing longer recovery times, and with cement leakage quite common. These findings lead to the conclusion that the subacute stage is optimal for vertebroplasty. Furthermore, it is suggested that the use of spinal orthoses and postsurgical supplementation for the bone matrix reduces the risk of new, adjacent compression fractures and increases anterior interbody restabilization. Importantly, the findings suggest that a presurgical magnetic resonance imaging evaluation is an absolute necessity.

[Complications of vertebroplasty]

Percutaneous vertebroplasty was first introduced in 1984 by Galibert et al. for the treatment of hemangiomas in the spine. The current indications for vertebroplasty also include compression fractures due to osteoporosis as well as osteolytic metastases and spinal myeloma lesions. With the numbers of percutaneous vertebroplasty performed by orthopedic and trauma surgeons, neurosurgeons, and radiologists steadily increasing, complications have also risen. Over the last 3 years an increasing number of cases with varying complications, their genesis, and their management have been reported in the literature. Complications include asymptomatic cement leakage, cardiovascular effects, embolism with lethal outcome as well as severe neurological deficits. This article presents a review of the complications reported in the literature, strategies for preventing possible complications as well as current concepts in therapy management. Several of our cases with cement leakages are presented.

Percutaneous vertebral augmentation

BACKGROUND CONTEXT

With the aging of the population, painful osteoporotic compression fractures are becoming more common.

PURPOSE

To review the physiologic implications of these injuries as well as treatment options and outcomes, especially with reference to newer, percutaneous "augmentation" procedures, that is, vertebroplasty and kyphoplasty.

STUDY DESIGN/SETTING

A literature review.

METHODS

No direct, randomized studies comparing vertebroplasty, kyphoplasty and standard, nonoperative care are available.

RESULTS

The growing literature suggests a role for kyphoplasty and vertebroplasty in the management of patients with intractable pain or progressive vertebral collapse after vertebral compression fracture. Both procedures likely offer similar rates of pain relief. Kyphoplasty, although more expensive, may allow fracture reduction. The void created with the balloon tamp allows a more viscous cement to be applied, thereby decreasing the risk of extravasation.

CONCLUSIONS

More study is required to understand the ideal role of these new techniques in the management of spinal osteoporosis and associated fractures. However, for carefully selected cases, current data suggest that the complication rates are low and pain relief can be profound.

Microsurgical interlaminary vertebro- and kyphoplasty for severe osteoporotic fractures

Object. Percutaneous vertebro- and kyphoplasty have become established methods for the treatment of uncomplicated osteoporotic vertebral fractures. In the setting of severe fractures involving fragmentation of the posterior wall and neural compromise, however, decompressive surgery cannot be performed and epidural cement leakage is poorly controlled. A microsurgical interlaminary approach for vertebro- and kyphoplasty was developed to allow spinal decompression and control of the spinal canal during augmentation.

Methods. Interlaminary vertebro- or kyphoplasty was performed in 24 patients with osteoporotic fractures involving neural compression or posterior wall fragmentation. After unilateral microsurgical fenestration, decompression of the spine, and gentle mobilization of the thecal sac, vertebro- or kyphoplasty was performed directly through the posterior wall of the fractured vertebral body. Cement was injected under microscopic and fluoroscopic control, with the option of immediate exploration of the exposed spinal canal. Thirty-four levels (T-8 to L-5) were treated. Mean blood loss was less than 100 ml and augmentation added 10 to 40 minutes to the entire procedure. Cement leakage associated with the kyphoplasty procedure was less than that in vertebroplasty. There were no major complications. One patient was lost to follow up. Clinical outcome was good or excellent in 17 of the 23 patients available for follow-up (1 to 31—month) evaluation.

Conclusions. The present microsurgical interlaminary approach for vertebro- and kyphoplasty enables treatment of severe osteoporotic fractures involving fragmentation of the posterior wall and neural compromise. Decompressive surgery is possible and the risk of epidural cement leakage is controlled intraoperatively. This technique can be regarded as a procedure on the treatment continuum between percutaneous augmentation and conventional open reconstruction.

Interdisciplinary approach to balloon kyphoplasty in the treatment of osteoporotic vertebral compression fractures

Osteoporotic vertebral compression fractures (VCFs) are associated with a series of clinical consequences leading to increased morbidity and even mortality. Early diagnosis and therapeutic intervention is desirable in order to remobilise patients and prevent further bone loss. Not all fractures are, however, sufficiently treatable by conservative measures. Here, vertebroplasty and kyphoplasty may provide immediate pain relief by minimally invasive fracture stabilisation. In cases of acute fractures, kyphoplasty has the potential to reduce kyphosis and restore the normal sagittal alignment of the spine. The complex nature of systemic osteoporosis, coupled with the intricate biomechanics of vertebral fractures, leads to a clinical setting which is ideally treated interdisciplinarily by the rheumatologist and spine surgeon.

Temperature elevation after vertebroplasty with polymethyl-methacrylate in the goat spine

Although the general complication rate for vertebroplasty is low, neural compression and thermal damage have been related to the use of polymethyl-methacrylate cement. This study focuses on the risk of thermal tissue damage after vertebroplasty. In this study, cavities were created by a transpedicular approach in the vertebral bodies (L3, L4, and L5) of four milk goats, and polymethyl-methacrylate cement was injected. In three locations (the bone-cement interface, the epidural space, and the disc space) the temperature was measured in regular intervals after injection of the cement. The mean injected volume was 0.8 ml, which accounted for a 22% volume fraction. The mean peak temperature of the bone-cement interface was 44.6 degrees C, while the maximum temperature at the epidural space and disc space was 37.0 and 37.5 degrees C, respectively. The local temperature measured after in vivo vertebroplasty did not reach values that are known to cause tissue necrosis.