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ORIGINAL ARTICLE
Year : 2018  |  Volume : 31  |  Issue : 4  |  Page : 1305-1311

Percutaneous vertebroplasty in the treatment of thoracolumbar fractures


1 Department of Orthopedic Surgery, Faculty of Medicine, Menoufia University, Menoufia, Egypt
2 Department of Orthopedic Surgery, El-Helal Hospital, Cairo, Egypt

Date of Submission06-Jun-2017
Date of Acceptance25-Aug-2017
Date of Web Publication14-Feb-2019

Correspondence Address:
Mohammed N Ali El Agreed
El Behera, Damanhour Abdelsadek Elshazly Street
Egypt
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/mmj.mmj_391_17

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  Abstract 


Objective
The objective was to determine the effect of percutaneous vertebroplasty (PV) through cement injection in relief of pain in case of painful osteoporotic and pathological thoracolumbar fractures.
Background
Vertebroplasty is a percutaneous polymethylmethacrylate cement injection inside the vertebral body through the pedicle and used mainly in the treatment of painful osteoporotic and pathological spinal fractures.
Patients and methods
A total of 20 patients in this study had thoracolumbar fractures (15 of them had osteoporotic fractures and five of them had pathological fractures). Patients were submitted into one of the three age groups. Group 1: less than 60 years, group 2: between 60 and 70 years, and group 3: above 70 years.
Results
The analgesic effect of PV was evaluated using visual analogue scale and activities of daily living immediately after operation and the patients were followed for 6 months radiologically and clinically using these scales. All of them were improved and four of them had cement leakage with no neurological insult. One of them had leakage with neurological insult which is improved by overnight injection of methylprednisolone.
Conclusion
PV has become common in many practices worldwide. It has been used by surgeons as a good therapy for the treatment of painful osteoporotic and pathological compression fractures of the spine which do not respond to medical treatment of osteoporosis. Nowadays, it has been the best option of treatment for these compression fractures in the world. PV is a simple operation and can be done in an outpatient clinic. Pain relief has been high and risks low, when done by experienced surgeons who exercise good judgment.

Keywords: bone cements, compression, osteoporosis, vertebrae, vertebroplasty


How to cite this article:
Hadhoud MM, Zayda AI, Ali El Agreed MN. Percutaneous vertebroplasty in the treatment of thoracolumbar fractures. Menoufia Med J 2018;31:1305-11

How to cite this URL:
Hadhoud MM, Zayda AI, Ali El Agreed MN. Percutaneous vertebroplasty in the treatment of thoracolumbar fractures. Menoufia Med J [serial online] 2018 [cited 2024 Mar 29];31:1305-11. Available from: http://www.mmj.eg.net/text.asp?2018/31/4/1305/252053




  Introduction Top


Osteoporotic fractures mostly occur in the spine. These spinal fractures called vertebral compression fractures (VCFs) occur in nearly seven million patients each year around the world. An osteoporotic vertebral fracture is more frequent than osteoporotic fractures in another site in the body such as the hip and wrist. In the elderly, osteoporosis is not the only cause of VCFs[1].

Most of the physicians do not prefer surgical interference in osteoporotic vertebral fractures. From the surgeon's point of view, a primary interest is confirming that there is no neoplastic or infectious lesion and the fracture is secondary to this lesion. The decision to do surgery is dependent on whether the spine is stable or unstable and on the presence of a neurological deficit or not. Stable VCFs usually are amenable to nonsurgical treatment. Unstable VCFs and/or VCFs resulting in neurologic deficit may require surgery[2].

Percutaneous cement augmentation may be an excellent solution for patients with osteoporotic vertebral fractures and not responding to medical treatment. Many studies suggest that this technique result in pain relief for patients with painful osteoporotic and neoplastic VCFs[3].

Bontox was the first surgeon who did percutaneous vertebroplasty (PV) in 1984, and reported in the literature in 1987, for the treatment of pain caused by cervical haemangioma[4].

This operation has rapidly become the best solution for treatment in painful VCFs which are not responding to medical treatment. Vertebral fractures usually become evident due to pain which can have variable intensities and may affect a patient's daily living activities, such as back pain, limitation of normal daily life, psychosis, disability and height loss caused by vertebral collapse, spinal instability and, in many cases, kyphotic deformity that could interfere with the functional vital and total lung capacities due to decrease in the volume of lung capacities or due to painful restriction of respiratory pattern[4],[5].

Osteoporosis, neoplasm (including metastasis and primary spinal tumours), large hemangiomas are the most common causes of secondary pathological vertebral fractures. Some patients who are resistant to conservative therapy such as analgesics, braces, immobilization and physical therapy[6],[7],[8], moreover develop side effects from prolonged course of analgesics. Many authors think that vertebroplasty is a successful technique, with a 70–90% of higher effectiveness for short-term pain reduction and return to normal activity, but long-term effectiveness is still debatable[9],[10],[11].

Vertebroplasty is usually done as an outpatient procedure. Chung et al.[12] have discovered that this procedure in treating osteoporotic fractures is successful in ∼90% of the cases. Vertebroplasty may be the best solution for the pain resulting from giant haemangiomas of the vertebral body not responding to conservative treatment and can relief pain in patients with pathological fracture secondary to metastasis or primary spinal tumour[12].

The postmortem studies have shown that the injection of a mixture of polymethylmethacrylate (PMMA) in the vertebral bodies restores strength in vertebral bodies[13].

So, our aim in this study was to determine the effect of cement injection in vertebral bodies in pain relief in thoracolumbar fractures.


  Patients and Methods Top


The material of this work included 20 cases of thoracolumbar spinal fractures treated by PV through cement injection using uni/bipedicular approach at the El-Menoufia University Hospital and El-Helal Hospital in Cairo. Cases were operated upon between February 2016 and August 2016.

Primary diagnosis of vertebral body collapse was done after a traumatic incident in all patients.

Patient inclusion criteria

Pathological fractures where pain is severe and debilitating without neurological insult.

Osteoporotic fractures where pain does not respond to usual medical treatment of pain and osteoporosis.

Patient exclusion criteria

Healed painless osteoporotic vertebral fracture that is completely healed as evident by short-τ inversion recovery MRI or is well responding to conservative management.

Bad coagulation profile and presence of blood diseases.

Presence of infection such as discitis/osteomyelitis or sepsis which may be suppurative or cold abcess (Pott's disease of the spine, active infection).

Invasion of the spinal canal by retropulsed bone fragment or tumours invading the epidural space.

All patients suffering from neurological manifestations such as paraplegia or urinary or faecal incontinence.

Unstable vertebral compression or distracting fractures involving the posterior complex. The methodology includes three stages.

Preoperative stage

Preoperative assessment: preoperative preparation, intraoperative stage includes, equipment used, operative technique, postoperative stage includes: clinical assessment, radiological assessment.

Duration of symptoms

The duration of symptom is variable according to the diagnosis. The duration of symptoms was divided into two categories. In osteoporotic fractures patients (80%) had the pain ranging from 9 days (acute fractures) to 90 days, average 49.5 days. In malignant spinal fractures patients (20%) had the pain ranging from 24 to 150 days (intraoperative stage). All patients were treated by vertebroplasty using the percutaneous unipedicular portal 'unipedicular access' (19 patients) or bipedicular portal 'bipedicular access' (one patient) under general anaesthesia in all patients except one case under local anaesthesia.

Equipment used in percutaneous vertebroplasty

PV was performed by using a single-plane fluoroscopic image switching the machine between anteroposterior (A-P) and lateral during the procedure (Ziehm Imaging Inc., Orlando, Florida, USA). A complete set of PV tools was used for every patient.

The set contains the following pieces: Needle A 10 or 15 G, special bevelled-edge needle. Cement gun (pressurized syringe) (Mendec Spine; Teres Medical Company, Verona City, Italy).

Surgical technique

PV was done under complete aseptic technique. A c-arm device is positioned to obtain an A-P view. Modifying the position of the c-arm device according to the need for the transpedicular approach can be found by making the angle of the A-P tube until the maximum profile is seen over the pedicle (5°–10° angulations). The pedicle is located with fluoroscopy and appears oval. After complete aseptic condition and draping the area overlying the access site and a small skin incision under the guidance of fluoroscopy, advancement of the needle through the transpedicular approach is continued till it reaches the anterior third of the vertebral body. The pedicle is punctured in its most lateral part using 10 or 15 G disposable Jamshidi-type needle. Assisted surgical hammering may help in advancement and cortical penetration of the used needle. The A-P and lateral fluoroscopic guidance help the surgeon to determine the proper advancement of the needle. When the bevelled tip of the needle reaches the medial wall of the pedicle, the C-arm is made to lateral view to be sure that we have reached the vertebral body. The needle bevel is turned to allow the needle to be positioned in the middle of the vertebra.

Stop the needle advancement when the needle tip is placed in the anterior one-fourth to one-third of the vertebral body in the lateral view and in the midline of the vertebral body in the A-P view with the expectation that the central portion of the vertebra can be filled [Figure 1]a,[Figure 1]b,[Figure 1]c,[Figure 1]d.
Figure 1: (a) Skin incision by a scalpel after identification of the level; (b) needle progression under image; (c) hammering of the needle; (d) mixing of the cement; (f) injection of cement and (g) withdrawal of the needle.

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In series vertebral bodies were injected. Unipedicular injections were performed in 19 cases, and bipedicular injections were performed in one vertebral body. When the body of the vertebra cannot be well filled by unipedicular injection, the bipedicular injection can be used.

Preparation of the cement

Start the preparation of cement once the needle is at the optimal position. Good mixing of the two parts of PMMA (the liquid monomer and the solid polymer) is necessary to obtain a haematogenous pasty form of cement.

During the first 40 s after mixing, the cement has a thin consistency. It then becomes pasty and thick. Distal venous cement migration can be prevented by injection of cement at pasty polymerization phase [Figure 1]d.

Injection of the cement

Fluoroscopic control is strictly a must at this stage of the procedure through the lateral view. PMMAs have a long setting time (the mean setting time of the vertebroplasty cement used in our study is 15 min, depending on the room temperature) and during that time, the cement keeps almost the same viscosity. The suitable temperature is as close as possible to 20°C. Higher temperatures will reduce the setting time. Lower operating room temperature will lengthen the injection and setting time. In these cases, injection set was used with a special bevelled needle for the introduction of the cement into the vertebral body. After the positioning of the needle, the pressure syringe allows the surgeon to maintain steady pressure during the injection of the cement by slowly turning a screw. It is very important to stop the injection immediately if there is even a minor cement leakage [Figure 1]e.

Injection of the liquid PMMA had to be stopped in the event of when the vertebral body was filled; when PMMA passed to the posterior fourth of the vertebral body; or when PMMA entered the disc, epidural space or veins, foramen, or paravertebral space or veins.

In this study, contralateral access is seldom necessary to obtain a good vertebral filling (only one case). Stylet had to be replaced after vertebral filling, again under fluoroscopic control, before the cement begins to set (because the needle itself contains about 1 ml of cement). Then, remove the needle carefully and slowly. Cement becomes relatively more hard and hot after 7 min of mixing. Monitoring of arterial pressure is important during the procedure because PMMA injections can cause transient hypotension. The total procedure time ranged from 20 to 50 min. The average amount of cement injected into patients with osteoporotic fractures is ∼4 ml while, in patients with tumours, a smaller volume of cement is usually injected [Figure 1]f.

Postoperative care

Immediate postoperative care

Early walking and ambulation assisted by braces for all patients postoperatively for 1–3 days with early walking in the second day of the procedure.

On the second day after operation all patients were allowed to discharge from the hospital. The only two exceptions to delay this discharge were a small number of patients (four cases) who were kept in the hospital for oncological management and presence of neurological insult.

Clinical assessment

After PV all patients had to wear orthotics for 1–3 days. This assessment related to the original pain and not to additional pain. After the procedure, the same visual analogue scale (VAS) was applied by the treating physician and followed at 1, 3 and 6 months.

Long-term follow-up

All patients were followed up for at least 6 months postoperatively. Follow-up was done according to a predetermined time schedule, which was followed as long as no complications occurred that necessitated shorter follow-up intervals.

At each follow-up visit the same postoperative evaluation items were reviewed and recorded by VAS and activities of daily living (ADLs). Thus patients selected for the current thesis had the following criteria in common.

They all had the diagnosis of pathological vertebral collapse (osteoporotic or malignant).

MRI showed marrow oedema denoting unhealed collapse.

They all underwent surgical treatment in the form of 'PV'.

They were all followed up for at least 6 months.

Statistical methods

All data were collected, tabulated and statistically analyzed using statistical package for the social sciences 19.0 for windows (SPSS; SPSS Inc., Chicago, Illinois, USA) and MedCalc 13 for windows (MedCalc Software BVBA, Ostend, Belgium). The qualitative data were presented as number and percentages, while quantitative data were presented as mean, SD and ranges in parametric distribution.

The comparison between two groups with qualitative data was done by using χ2-test. The comparison between two independent groups with qualitative data and parametric distribution was done using independent t-test.

The comparison between two paired groups with quantitative data and parametric distribution was done by using paired t-test.

Comparison between two or more groups can be done using repeated measures of analysis of variance.

Power of study is 0.95 and the prevalence of VAS improvement among the 20 patients in our study is 0.7.


  Results Top


Patients' anthropometric data and operative data were equivalent among the groups [Table 1]. [Table 2] gives the level of fracture among the studied patients. Indication, portal, cement volume and cement filling of the studied patients and the effect of vertebroplasty in pain relief after surgery were measured using VAS scale and ADLs. A comparison of the preoperative results of with postoperative results is demonstrated in [Table 3], [Table 4] and [Figure 1], [Figure 2]. The P value was less than 0.001 which means that the effect of vertebroplasty in the treatment of pain relief is highly significant in pain relief in the treatment of osteoporotic and pathological vertebral fractures.
Table 1: Age, sex and anthropometric measures of the patients

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Table 2: Level of fracture among the studied patients

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Table 3: Visual analogue scale at different points of measurement

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Table 4: Preoperative and postoperative activities of daily living of the studied patients

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Figure 2: Visual analogue scale at different points of measurement.

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The relation between vertebroplasty and pain relief is highly significant as VAS scale and ADLs improved after doing surgery; so vertebroplasty is very effective in pain relief in osteoporotic and pathological vertebral fractures [Figure 1] and [Figure 2].

The analgesic effect of PV was evaluated using VAS and ADLs immediately after operation and the patients were followed up for 6 months radiologically and clinically using these scales. All of them were improved and four of them had cement leakage with no neurological insult; one of them had leakage with neurological insult which is improved by overnight injection of methylprednisolone [Figure 3].
Figure 3: Preoperative and postoperative activities of daily living of the studied patients.

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  Discussion Top


The osteoporotic patients are relatively younger (mean age: 66.3 years) than those of other studies by Cortet et al and Karmellus et al. Moreover, women (15 cases) are more affected than men (five cases) forming a ratio of 3: 1. This is a sex distribution that matches to other studies.[13],[14].

Treatment of osteoporotic vertebral fractures with PV appears safe and results in substantial immediate pain reduction and improved functional status (graded by VAS, mean preoperative: 8.35 ± 0.67, mean 6 months postoperative: 1.3 ± 0.73) and improvement in ability to perform ADLs, avoiding complications of prolonged immobilization, the potential adverse effect of strong analgesics such as opiates to which elderly people are particularly suspected. Moreover, NSAIDs have significant toxicity.

The treatment of long-standing fractures remains controversial but Daniel and Timothy stated that complete pain relief is after 24 months. Daniel reported that the earlier cement injection of osteoporotic vertebral fracture results in greater improvement of symptoms[15].

The radiological evaluation is a controversial point regarding the vertebroplasty procedures. One group of authors such as Barr et al. has emphasized the use of computed tomography (CT) to facilitate accurate needle placement, particularly in the thoracic spine. Lack of real-time visualization of cement leakage is the main disadvantage of the CT. According to Barr et al., this drawback may be avoided by smaller and more closely monitored injections[16].

Ideally, according to Barr et al.[16] andGangi et al.using combined CT and fluoroscopic guidance is the best option. Only prospective, randomized studies could compare guidance methods in terms of safety, duration of the procedure and cost.

David et al., Jensen et al. and others stated that the prevention of cement leakage from entering into the perivertebral plexus or into the inferior vena cava could be achieved by using venograms[14].

This and other studies by Cotton et al., have ensured that it is more than enough to use the fluoroscopic guidance without using fluoroscopic guidance and it is very safe. The single-side technique has the advantage of being easy and fast. Needle progression and cement injection are best assessed with radiographic procedures that allow both A-P and lateral fluoroscopic evaluation-assisted guidance without moving the patient. General anaesthesia or intravenous sedation is used because pain may be more during cement injection.

In the current practice, the injection of larger amounts of PMMA requires careful observation of well-opacified PMMA during vertebral body filling. In many cases in this study, it may be necessary to stop PMMA injection temporarily to let PMMA thicken or harden, after which injection can resume.

Portal

A transpedicular or posterolateral route could be used for the thoracic and lumbar spine. In this trial, the parapedicular route had not been used; all injections are done using the transpedicular route. Use of the transpedicular route is to avoid spinal segmental nerve injury and to decrease the risk of leakage of methyl methacrylate into the paravertebral tissue.

Schallen & Gilula[17] have stated that there is no statistical difference in unilateral filling and bilateral filling of cement in vertebral body when using unipedicular versus the bipedicular approach.

In the current study, unilateral injections were performed in 95% of vertebral bodies (19 cases) and bilateral injections were performed in one (5%) case.

However, because mostly in this study the unipedicular approach was used, it is difficult to compare single and double approaches (only one vertebral body). The double approach should be better for filling of the vertebrae, but the single approach allows placement of the needle tip within the contralateral vertebral half and through bevel positioning bilateral filling can be achieved. Indeed, filling across midline was achieved in 55% of unipedicular injections and filling across the midline in 100% of bipedicular injection (only single case).

More important than the radiographic outcome was the clinical outcome, in which no statistically significant difference was found between, filling across the midline and partial vertebral filling in terms of pain relief as measured with VAS.

Advantages of the unipedicular approach include the following. First, it would appear that less time would be needed for the unipedicular (one needle insertion) versus the bipedicular (two needle insertions) approach. Second, only one injection is needed instead of two, and the second injection in the bipedicular approach is frequently hampered by the indwelling barium opacification. Third, the incidence of fracture pedicle, root injury and dural tear is very less in unipedicular than in bipedicular injection. The choice of needle route depends on the experience of the practitioner.

Complications

Cement leakage

Cement extravasation occurs very frequently in vertebroplasty. It has been reported to occur in 38–72.5% of patients with malignant collapse by Weill et al., in 30% by Jensen et al., 59.5% by Gaughen et al. and 65% by Cortet et al.[13], of patients with osteoporotic VCF. Fortunately, it is well tolerated in the large majority of patients. However, cement extravasations is also the main source of clinical complications.

Cement leakage into the foramen is less frequent since the transpedicular approach is preferred to the classical posterolateral approach, which crosses the foramen. Both foraminal and spinal canal cement leakage may be due to breaking through the medial or inferior cortex of the vertebral pedicle at the time of approach. Radiculopathy is the major risk with neural foramina leaks. Gangi et al. have reported three instances of a neural foramina leak occurred immediately after the procedure: the filling of an epidural vein and neural foramina, causing intercostal neuralgia.

Potential cardiovascular changes with PMMA administration due to allergic reactions.


  Conclusion Top


PV has become common in many practices worldwide. It has been used by surgeons as a good therapy for the treatment of painful osteoporotic and pathological compression fractures of the spine which do not respond to medical treatment of osteoporosis. Nowadays, it has been the best option of treatment for these compression fractures in the world. PV is a simple operation and can be done in an outpatient clinic. Pain relief has been high and risks low, when done by experienced surgeons who exercise good judgment.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Black DM, Palermo L, Nevitt MC, Genant HK, Christensen L, Cummings SR. Defining incident vertebral deformity: a prospective comparison of several approaches. J Bone Miner Res 1999; 14:90–101.  Back to cited text no. 1
    
2.
Denis F. The three column spine and its significance in the classification of acute thoracolumbar spinal injuries. Spine 1983; 8:817–831.  Back to cited text no. 2
    
3.
McCormack BM, Benzel EC, Adams MS, Baldwin NG, Rupp FW, Maher DJ. Anatomy of the thoracic pedicle. Neurosurgery 1998; 37:303–308.  Back to cited text no. 3
    
4.
Ettinger B, Black DM, Nevitt MC, Rundle AC, Cauley JA, Cummings SR, et al. Contribution of vertebral deformities to chronic back pain and disability. J Bone Miner Res 2009; 7:449–456.  Back to cited text no. 4
    
5.
Silverman SL. The clinical consequences of vertebral compression fracture. Bone 1992; 13 (Suppl 2):S27-S31.  Back to cited text no. 5
    
6.
Turner JA, Fulton-Kehoe D, Franklin G, Wickizer TM, Wu R. Comparison of the Roland–Morris Disability Questionnaire and Generic Health Status Measures. Spine 2003; 28:1061–1067.  Back to cited text no. 6
    
7.
Jensen ME, Evans AJ, Mathis JM, Kallmes DF, Cloft HJ, Dion JE. Percutaneous polymethylmethacrylate vertebroplasty in the treatment of osteoporotic vertebral body compression fractures: technical aspects. Am J Neuroradiol 2010; 18:1897–1904.  Back to cited text no. 7
    
8.
Voormolen MHJ, Mali WPTM, Lohle PNM, Fransen H, Lampmann LEH, van der Graaf Y, et al. Percutaneous vertebroplasty compared with optimal pain medication treatment: short-term clinical outcome of patients with subacute or chronic painful osteoporotic vertebral compression fractures. The VERTOS study. Am J Neuroradiol 2007; 28:555–560.  Back to cited text no. 8
    
9.
Evans AJ, Jensen ME, Kip KE, DeNardo AJ, Lawler GJ, Negin GA, et al. Vertebral compression fractures: pain reduction and improvement in functional mobility after percutaneous polymethylmethacrylate vertebroplasty – Retrospective report of 245 cases. Radiology 2003; 226:366–372.  Back to cited text no. 9
    
10.
Tohmeh AG, Mathis JM, Fenton DC, Levine AM, Belkoff SM. Biomechanical efficacy of unipedicular versus bipedicular vertebroplasty for the management of osteoporotic compression fractures. Spine 1999; 24:1772–1776.  Back to cited text no. 10
    
11.
Anselmetti GC, Corrao G, Della MP, Tartaglia V, Manca A, Eminefendic H, et al. Pain relief following percutaneous vertebroplasty: results of a series of 283 consecutive patients treated in a single institution. Cardiovasc Intervent Radiol 2007; 30:441–447.  Back to cited text no. 11
    
12.
Chung SK, Lee SH, Kim D-Y, Lee HY. Treatment of lower lumbar radiculopathy caused by osteoporotic compression fracture: the role of vertebroplasty. J Spinal Disord Tech 2002; 15:461–468.  Back to cited text no. 12
    
13.
Cortet B, Cotten A, Boutry N, Flipo RM, Duquesnoy B, Chastanet P, et al. Percutaneous vertebroplasty in the treatment of osteoporotic vertebral compression fractures: an open prospective study. J Rheumatol 1999; 26:2222–2228.  Back to cited text no. 13
    
14.
Kallmes DF, Jensen ME, McGraw JK. Percutaneous vertebroplasty. Interv Radiol Spine 1997; 2004:285–296.  Back to cited text no. 14
    
15.
Kim DH. Unipedicular approach for percutaneous vertebroplasty. In: Kim DH, editor. Minimally invasive percutaneous spinal techniques. New York: Elsevier Saunders; 2011. 104–109.  Back to cited text no. 15
    
16.
Marshall R. Complications of spine surgery: treatment and prevention – Deiner S, Silverstein J. Anesthesia for patients with spinal cord tumors. In: Farag E, editor. Anesthesia for spine surgery. Clevland, Florida: Cambridge University Press; 2012. 247–250.  Back to cited text no. 16
    
17.
Schallen EH, Gilula LA. Vertebroplasty: reusable flange converter with hub lock for injection of polymethylmethacrylate with Screw-Plunger syringe. Radiology 2002; 222:851–855.  Back to cited text no. 17
    


    Figures

  [Figure 1], [Figure 2], [Figure 3]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]



 

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