Percutaneous Vertebroplasty

Percutaneous vertebroplasty is a popular and emerging minimally invasive technique. Polymethyl methacrylate (PMMA) is injected into the vertebral body under radiological guidance to maintain the stability and strength of the spinal column and to decrease patient pain. Galibert et al. (1) reported the first case in a patient with a painful vertebral hemangioma in 1987. In recent years, the indication was widened to include other painful osteolytic lesions of the vertebral body (2). Approximately, 700,000 people have vertebral body fractures secondary to osteoporosis, and this results in a decrease in patient quality of life (3). Today, vertebroplasty is used generally for two primary indications: the treatment of metastatic vertebra tumours and symptomatic osteoporotic vertebra compresion fractures (VCF).


INTRODUCTION
Percutaneous vertebroplasty (PVP) is a minimally invasive procedure for treating pain caused by vertebral fractures of various types, including osteoporotic, traumatic and neoplastic fractures. 1,2 Complications are not uncommon; however, they are usually not clinically significant. [1][2][3] Cement leakage can occur intravenously, paravertebrally, into the intervertebral disc, or into the spinal canal, disrupting the foraminal area or epidural space, [3][4][5] while intradural leaking is quite uncommon. 6 PVP can also raise the risk of neighboring vertebral fractures 4,7 Infections following surgery are uncommon, 8 and serious systemic complications are very rare, 9 but sometimes are fatal like fat embolism, 10 pulmonary embolisms, 11 cardiac injury, 12 or arterial, 13 or renal embolization. 14 Epidural bleeding exists; however, it is quite uncommon. 15 There are numerous publications on the beneficial effects of PVP; however, there are few reports on the risks associated with percutaneous vertebroplasty. The aim of the study was to evaluate the effects of treatment and complications of vertebroplasty on hundred and twenty vertebrae using polymethylmethacrylate cement (PMMA) focusing on the clinical manifestations and severity of PVP complications.

PATIENTS AND METHODS
A total of hundred and twenty PVPs in hundred individuals were performed at Suez Canal University Hospitals (Ismailia, Egypt) between 2010 and 2019.
Ethical Committee approval and written, informed consent were obtained from all participants.
All the patients met the following criteria: the vertebra was compressed by more than 50%, the posterior walls and pedicle of vertebral bodies were intact without neural compressive signs and decompression was not needed. There were seventy females (70%) and thirty males (30%), ranging in age from 24 to 74 years, with a mean age of 58 years.

Complications of Percutaneous Vertebroplasty
Sixty patients had osteoporotic fractures, forty-five of which were single level fractures, and fifteen of which were two to three level fractures. Thirty patients had malignant disease, including five cases of myeloma, five cases of prostate carcinoma, fifteen cases of breast cancer, and five cases of lung cancer metastases. Two patients had painful vertebral hemangiomas, and eight others suffered from severe post traumatic fractures. From a total of hundred patients with painful fractures, eightyfive patients had a single fracture, and fifteen subjects had two or more fractures. Table 1 shows the cause and the number of fractures. All the patients were admitted to the hospital because they were in excruciating pain or were experiencing an exacerbation of chronic pain. Patients were admitted after undergoing a computerized tomography (CT) or magnetic resonance imaging (MRI) within the previous two weeks. Up to six weeks from the onset of discomfort, all single fractures were identified as acute. In numerous fractures, the first level with a hyperintense signal within the bone marrow in a T2weighted sequence with fat suppression was defined as a new fracture, while the rest were classified as chronic.
We discovered a two-year history of documented fractures in twelve out of the fifteen individuals with multiple fractures. All these patients had been treated conservatively previously, and they all complained of persistent discomfort that had worsened in the latest weeks before PVP. From two to six weeks prior to augmentation, all patients had severe pain. There were eighty osteoporotic fractures treated out of hundred and twenty surgeries, and thirty malignant disease-related fractures. In traumatic fractures, eight PVP were done. Solitary painful vertebral hemangiomas were seen in two cases. Seventy-five lesions (62.5%) were found in the thoracic region, whereas forty-five subjects (37.5%) were found in the lumbar region. The fractures were all compression fractures. (Table 1).

Surgical technique
Patients were lying on a radiolucent surgery table in a prone position. Under the guidance of a C-arm image intensifier, the location of the pedicle of the vertebral arch was used to determine the needling spot. Routine sterile techniques were used to prepare and drape the skin.
The surgery was carried out under local or general anesthesia. In all patients, vertebroplasty was performed with a 13-gauge needle and a bilateral transpedicular route. We never utilized liquid cement; instead, we injected medium viscosity cement. Under fluoroscopic guidance, polymethylmethacrylate (PMMP) was carefully injected. When the cement reached the posterior wall of the vertebral body, the injection was discontinued. As PMMP formed, the cannula was taken out three to five minutes later.

Observation parameters
The effectiveness of the treatment was evaluated using a hundred points visual analogue scale (VAS) twelve hours after surgery, seven days later, thirty days later, and then every six months for the next year. We simply looked at the level of pain in the vertebral column. Before the operation, the height of the vertebral body was measured. During the procedure, the cement volume, distribution, and leakage in the vertebral body were observed and documented. During and after the procedure, the patient's blood pressure, heart rate, and respiration rate were all monitored. Cement volume, distribution, leakage, and vertebral height were all measured using X-rays.

Statistical analysis
The data was analyzed using the statistical package for the social sciences (SPSS 10.0). P value < 0.05 was considered as statistically difference.

RESULTS
The injection volume of PMMA was 0.5 to 3 mL in the thoracic area and 1 to 4 mL in the lumbar area. Prior to surgery, all patients experienced considerable pain on a VAS scale between seventy and hundred, with a mean of 93. With a mean VAS of 35, 95 percent of patients reported significant pain alleviation twelve hours following surgery.
After a year, more than 90% of patients reported pain alleviation, and the VAS score had marginally altered to an average of nineteen. (Fig. 1)   were all satisfactory.
Two patients had modest pain improvement, with leakage of cement into surrounding tissues as in (Fig. 2). Another three patients experienced no pain alleviation, all of them had intracanal leakage as in (Fig. 3). The 30th day assessment found that two of the three patients with leaking into the spinal canal had significant pain relief, while the third patient's discomfort remained the same. In forty-five augmented vertebrae, 37.5% of all surgeries, various complications were reported. Leakage was seen in 35% of osteoporotic fractures, 20% of neoplastic fractures, and 12.5% percent of traumatic fractures. We found paravertebral vein embolism in one patient with vertebral hemangiomas, but no additional complications. The most common PVP consequences in neoplastic and osteoporotic patients were leakage to surrounding tissue and paravertebral vein embolism. Intradiscal leakage was detected in 10% of individuals from all classes as in (Fig. 4), with no clinical signs. Intracanal leaking occurred in three individuals, one with a neoplastic condition and the other two with osteoporotic fractures. One patient with multiple myeloma experienced monoparesis of the lower extremities, whereas another developed paraparesis due to osteoporosis (Fig. 3).
Decompressive laminectomy was required for both of them. After decompressive laminectomy, both of them demonstrated a steady improvement in motor function. After a 30-day evaluation, it was discovered that they had pain relief; however, in 14% of patients, there was evidence of leakage into the surrounding tissues. One case showed cement leak into the needle tract (Fig. 5). There were no statistical differences between the thoracic and lumbar areas in terms of the incidence of complications. There were no variations between the ages and sex groups when it came to the number of complications. There were no statistically significant differences in treatment outcomes between patients who had augmentation complications and those who did not. Satisfactory to excellent pain relief was observed after vertebroplasty in more than 95% of patients.

DISCUSSION
PVP is a standard treatment for osteoporotic and malignant vertebral fractures, among a variety of other alternatives. 16 The actual mechanism of pain alleviation provided by vertebroplasty is unknown. Pain alleviation was thought to be secondary to thermal energy initially. In vivo, temperatures following vertebroplasty are not high enough to produce thermal necrosis of sensory nerves, according to new research. Alternatively, enhanced vertebral body strength and stiffness, as well as decreased mobility of the vertebral body and periosteal and interosseous nerves, are likely to provide pain alleviation after vertebroplasty. According to cadaveric studies, there is new bone growth after PVP. 17,18 Despite some disagreement over the effectiveness of vertebroplasty, most studies show that treatment reduces pain. Significant pain relief appears shortly after surgery and lasts for quite some time. 2,19 With time, the evidence for vertebroplasty in the treatment of osteoporotic fractures has grown. 20 Technically, vertebroplasty with narrow-gauge needles is simple and safe to do. Despite the critics, treating fractures with cement injections gives immediate pain relief and improves quality of life. Because it is exceedingly unlikely that an elderly patient could also be cured by immobilization, delaying therapy is not recommended. 21 When doing vertebroplasty, it is critical to pay close attention to anatomical structures. 16 PVP is usually safe, however it has been linked to serious clinical consequences, such as spinal cord compression, 5,6 or systemic embolism, 11,14,22 as well as less serious issues, such as infection or radicular pain. 8,23 Temporary pains following the treatment, as well as cement leaking into the intervertebral disc area and paravertebral soft tissues, are minor risks. 16 Infection and cement leak into the epidural area are examples of moderate consequences. 16 Local PMMA leakage is common, affecting up to 90% of patients, however it usually causes no symptoms. Leaks into the paravertebral veins can cause pulmonary embolism, cerebral embolism, or heart perforation, among other serious problems. 11,12 Because of the possibility of damage of the vertebral body cortex and increased vascularization, leakage is more common in the treatment of malignant lesions. 3,24 Infections, epidural hemorrhage, fat embolisms, cardiac injury, or arterial or renal embolism are among the consequences of PVP, according to literature. [8][9][10][11][12][13][14][15] These complications are quite uncommon, and we have not seen any in our experience. The amount of PMMA needed for the treatment can be kept to a minimum. Small quantities of PMMA can greatly relieve pain and help to prevent a variety of PVP complications.
PVP is a minimally invasive procedure; nonetheless, the incidence of problems, particularly extra-vertebral PMMA leaking, is high (up to 70%). 2,19,22 Complications were found in 37.5% of all surgeries done in our study, on the other hand, 97.5% showed no clinical signs. There was no difference in pain relief between those who had leaks and those who did not have any complications. Most of the patients' cement leakage was minor and did not necessitate further treatment. Leakage into the spinal canal was the only exception. It happened in three out of 100 patients, and in two of them, it resulted in serious consequences such as monoparesis and paraparesis, as well as widespread sensory problems. Five patients suffered new fractures throughout the one-year follow-up period. This opposes the theory that PVP causes additional compression fractures in neighboring vertebrae. 25

CONCLUSION
Vertebroplasty is a minimally invasive surgical procedure with a low risk of complications. In more than 95% of patients, vertebroplasty effectively decreases pain. Nearly 40% of patients experience local problems. However, in over 90% of these problems, there was no effect on treatment outcomes.

Disclosure
The authors report no conflict of interest in the materials or methods used in this study or the findings specified in this paper