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

Morphological features of basivertebral foramen among different age groups: Recognition in spine

Background

Basivertebral foramen (BF) is a vessel and nerve passage in the posterior wall of vertebral body (VB). Our goal was to report BF's morphological characteristics in different age groups of mainland Chinese adults and to evaluate the relationship between BF's morphology and factors such as age, gender, heavy work, size and level of VB.

Methods

We enrolled 300 adults among persons who came to our hospital for health examination. We measured BFs and VBs' parameters on T1 weighted sagittal lumbar spine MR images. We also assessed following potential predictors: gender, body height, body weight, body mass index, alcohol use, habits of smoking and drinking, type of work (physical work or non-physical work). A stepwise multivariate linear regression analysis was conducted to identify predictors of BF's height.

Results

People above 60 have significantly bigger BFHr than those in young adulthood and in the middle ages at all five levels, while they have shallowest BFs, especially at L3. Multiple linear regression resulted in a formula that accounted for 30.1% of the variability in the height of basivertebral foramen. Significant predictors included: gender, age, level, vertebral height and heavy work.

Conclusion

Age is the highest weight in all factors on the height of BF. BF is closer to the upper endplate. The BF was relatively higher and deeper in the female lumbar spine. Heavywork results in lower BF. Last but not the least, as we supposed, BF gets shallower and higher compare to VB with age.

Level of evidence

Prognostic level III. See instructions for authors for a complete description of levels of evidence.

Delayed neurological deficits caused by cement extravasation following vertebroplasty: a case report

Delayed neurological deficits secondary to percutaneous vertebroplasty caused by cement leakage is a rare condition. Although cement extravasation during percutaneous vertebroplasty is not uncommon, most cases are clinically asymptomatic, and symptomatic cement extravasation that requires surgical excision is rarely reported. Herein, a case of L4 radiculopathy secondary to cement leakage is reported that involved the delayed onset of neurological symptoms. The patient was treated using a minimally invasive transforaminal endoscopic approach. The clinical and imaging findings and treatment methods are discussed.

Full-endoscopic spine surgery for radiculopathy after osteoporotic vertebral compression fractures: a case report

Full-endoscopic spine surgery (FESS) is a suitable treatment for lumbar disc herniation (LDH) and foraminal stenosis. Here, we describe the usefulness of FESS for treating radiculopathy after osteoporotic vertebral compression fractures (OVCFs). Between October 2018 and April 2019, three female patients (mean age, 81.7 years) with radiculopathy after OVCFs underwent FESS. Decompression of the corresponding nerve root was achieved using several FESS techniques, including foraminoplasty, discectomy, and removal of osteophyte or cement leakage. The mean operative time was 60.7 min. Preoperative and postoperative statuses were evaluated using numerical rating scale (NRS) scores. The mean pre- and postoperative NRS scores were 9 and 2.3, respectively. We observed no postoperative complications. Our results demonstrate that FESS is a safe and effective minimally invasive treatment for radiculopathy after OVCFs, with the potential to be an alternative to vertebroplasty, balloon kyphoplasty (BKP), or lumbar interbody fusion.

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.

In vitro studies of composite bone filler based on poly(propylene fumarate) and biphasic α-tricalcium phosphate/hydroxyapatite ceramic powder

While many different filler materials have been applied in vertebral augmentation procedures, none is perfect in all biomechanical and biological characteristics. To minimize possible shortages, we synthesized a new biodegradable, injectable, and premixed composite made from poly(propylene fumarate) (PPF) and biphasic α-tricalcium phosphate (α-TCP)/hydroxyapatite (HAP) ceramics powder and evaluated the material properties of the compound in vitro. We mixed the PPF cross-linked by N-vinyl pyrrolidinone and biphasic α-TCP/HAP powder in different ratios with benzoyl peroxide as an initiator. The setting time and temperature were recorded, although they could be manipulated by modulating the concentrations of hydroquinone and N,N-dimethyl-p-toluidine. Degradation, cytocompatibility, mechanical properties, and radiopacity were analyzed after the composites were cured by a cylindrical shape. We also compared the study materials with poly(methyl methacrylate) (PMMA) and PPF with pure HAP particles. Results showed that lower temperature during curing process (38-44°C), sufficient initial mechanical compressive fracture strength (61.1±3.7MPa), and gradual degradation were observed in the newly developed bone filler. Radiopacity in Hounsfield units was similar to PMMA as determined by computed tomography scan. Both pH value variation and cytotoxicity were within biological tolerable limits based on the biocompatibility tests. Mixtures with 70% α-TCP/HAP powder were superior to other groups. This study indicated that a composite of PPF and biphasic α-TCP/HAP powder is a promising, premixed, injectable biodegradable filler and that a mixture containing 70% α-TCP/HAP exhibits the best properties.

Anterior thoracolumbar reconstruction surgery for late collapse following vertebroplasty: report of three cases

Although vertebroplasty (VP) using polymethylmethacrylate (PMMA) is thought to be an effective procedure for osteoporotic vertebral compression fractures, several complications have been reported. In this paper, we present three patients who developed local kyphotic deformity as a result of late collapse of the cemented vertebrae. In all patients we safely removed the PMMA block through an anterior approach and anterior reconstruction was performed successfully. In only one patient who had a three column unstable injury with fractured posterior elements was additional posterior spinal fixation needed. In conclusion, VP is thought to be an effective and minimal invasive technique to treat osteoporotic compression fractures in older patients. Once collapse or nonunion of the treated vertebral body occurs, however, removal of the cement and anterior reconstruction may be required to realign of the affected segments and reconstruct the spine.

Serious complication of cement augmentation for damaged pilot hole

Polymethl methacrylate (PMMA) screw reinforcement is frequently used in osteoporotic bone as well as in damaged pilot holes. However, PMMA use can be dangerous, since the amount of applied cement is uncontrolled. A 47-year-old male with traumatic cervical spondylolisthesis at C6-7 underwent anterior cervical plate fixation. During repeated drilling and tapping for false trajectory correction, a pilot hole was damaged. Although it was an unconventional method, PMMA augmentation was tried. However, PMMA was accidentally injected to the cervical spinal cord owing to lack of fluoroscopic guidance. The PMMA was surgically removed after corpectomy and durotomy. The patient had left side hemiparesis (Grade 2/5) immediately post operation. The patient improved spontaneously (Grade 4/5) except for 4th and 5th digit extension. Here, we report a rare complication of PMMA extrusion in the spinal cord during a damaged pilot hole injection, which has not previously been described.

Histological changes of an injectable rhBMP-2/calcium phosphate cement in vertebroplasty of rhesus monkey

STUDY DESIGN

A histologic study of recombinant human bone morphogenetic protein-2/calcium phosphate cement (rhBMP-2/CPC) using adult rhesus monkeys in vivo.

OBJECTIVE

To evaluate the histologic changes of rhBMP-2/CPC in vertebroplasty and determine the feasibility of this bone substitution instead of polymethylmethacrylate (PMMA).

SUMMARY OF BACKGROUND DATA

Previous studies have shown that the new rhBMP-2/nanoscale CPC has a suitable strength and injection for vertebroplasty. However, the osteoinductive properties and biodegradable characteristics are still unclear.

METHODS

Percutaneous vertebroplasty (PVP) was performed in 4 adult rhesus monkeys of 2 groups. Ten vertebral bodies (VBs) from T10-L7 of each rhesus were selected, and the 20 VBs in each group were randomly divided into 3 subgroups. Subgroup A (rhBMP-2/CPC): 8 VBs, filled with rhBMP-2/CPC; Subgroup B (PMMA): 6 VBs, filled with injectable PMMA; Subgroup C (control): 6 VBs, filled with normal saline. The 2 rhesus monkeys from each of the groups were killed at 2 and 6 months after operation, respectively. Individual specimens from the 40 VBs were collected for histologic observation.

RESULTS

In subgroup A, radiographic and histologic observations showed that the part of the rhBMP-2/CPC cement degraded with new bone and new vessel ingrowths, into the material, after 2 months. In addition, gaps, fibrous hyperplasia, or sclerotic callus were not found in the interface. After 6 months, the cement was nearly all replaced by mature bone tissue. In subgroup B, the inflammatory cell infiltration and fibrous membrane gapping were found after 2 months, and subsided partly at 6 months. But no new bone formation and material degradation were discovered. In subgroup C, the tunnels were filled with irregular new trabeculae after 2 months and unrecognizable from the surrounding mature bone after 6 months.

CONCLUSION

It is confirmed that the rhBMP-2/CPC is an osteoinductive and biodegradable material (in animal trials). It may also be an alternative to PMMA in order to achieve biostabilization in a vertebroplasty.

Cement leakage in a symptomatic vertebral hemangioma: a case report and review of the literature

We present the case of a 50-year-old male with consistent back pain, not resolving with conservative treatment. Plain radiograms demonstrated a lytic lesion at the level of the 8^th thoracic vertebra. Thorough examination with computerized tomography and magnetic resonance imaging revealed a hemangioma extending to the posterior third of the vertebral body, compressing the spinal cord at the level of 8^th thoracic vertebra. A percutaneous vertebroplasty was performed. The post-operative computerized tomography scan demonstrated cement leakage. After thorough cement removal combined with extensive decompression and posterior stabilization, the patient reported gradual improvement of his symptoms and was able to return successfully to his work a few months later.