YANG Zuozhang 杨祚璋，XU Jianbo 许建波，JIN Congguo 金从国，LIU Pengjie 刘鹏杰，YUAN Tao 袁涛，QIAN Baosheng 钱保生，ZHANG Jinyu 张晋煜，LI Wengzhong 李文忠，LI Jianlin 李建林，XIAO Yanbin 肖砚斌，PENG Ming 彭敏，LI Yu 李浴，LUAN Li 栾丽

Department of Orthopaedics The Third Affiliated Hospital of Kunming Medical College Tumor Hospital of Yunnan Province Kunming Yunnan 650118 China

 

OBJECTIVE  To explore the clinical effect in patients with metastatic spinal tumors treated by percutaneous vertebroplasty (PVP ) under the guidance of digital subtraction angiography (DSA ).

METHODS  A total of 110 cases with a metastatic spinal tumor were divided into 55 cases in the treatment group (group A ) and 55 cases in the control group (group B ). The general clinical data were statistically analyzed before treatment with the parameters showing no differences. Group A was treated by PVP and chemotherapy as well. The group B was treated by the regular chemotherapy and regular radiation therapy. The same chemotherapy program was used for the same type of disease. All cases were provided with a follow-up survey for 12 months. During the follow-up survey changes in the quality of life in evaluation of and in vertebral column stability as well as adverse reaction were observed.

 

RESULTS  The statistics showed a significant difference between the 2 groups specifically changes in the quality of life and evaluation of bone pain (P＜0.05t₁=2.74t₂=9.02﹚. During the follow-up survey 5 cases in group A died of other organ complilcations the death rate being 9.1 (5 out of 55) but all survived more than 3 months following PVP. The vertebral columns of the survivors were kept stable with no pathological fractures occurring in the vertebral bodies filled with bone cement there were no obvious adverse reactions and paraplegia occurred. Thirteen cases died in group B with a death rate of 23.6 (13 out of 55). Pathological compression fractures in the vertebral bodies occurred in 30 cases and 12 cases of complicated paraplegia were noted. The incident rate of paraplegia was 21.8 (12 out of 55).

 

CONCLUSION:  PVP is a simple operation causing only small wounds and few complications. It can effectively alleviate pain of metastatic spinal tumors in patients improve quality of life and reduce the incidence rate of paraplegia.

 

KEYWORDS:  percutaneous vertebroplasty spine metastatic tumor intervention bone cement

 

   Metastases are the primary complication of malignant tumors. Metastatic spinal tumors are the most commom metastatic bone tumors with 20 of malignant tumors involving bone metastases. In most cases metastatic lesions occur in the thoracic spine some in the lumbar spinal and some in the cervical spine ^[1].There are many therapeutic methods to treat metastatic spinal tumors but no ideal therapy is known at present. In our hospital since 2003 we treated 55 patients with metastatic spinal tumors using percutaneous vertebroplasty (PVP) under the guidance of digital subtraction angiography (DSA). The procedure produced good clinical results which are summarized in this report.

 

 

A total of 110 patients with metastatic spinal tumor were divided into 55 cases in the treatment groupand 55 cases in the control group (Table 1). All cases which were chosen met the following criteria: (1) the pathological diagnosis was based on the original focuses or pathological centra (2) there were no symptoms related to the compression of the spiral cord or nerve roots (3) all of the patients presented with a combination of neck bake or waist pain (4) the number of pathological centra was no more than 3. The clinical data listed in Table 1 showed no statistically significant differences P＞0.05. After treatment with PVP the patients in the treatment group were treated by the regular chemotherapy. Patients in the control group were treated by the regular radiation therapy at spinal tumor focuses and whole chemotherapy.

 

 

A China-produced instruments for percutaneous vertebroplasty was used including the puncture needles and the device to increase pressure in the spiral injector (       produced by Shan dong Longguan Company). The puncture needles were comprised of those for the cervical spine thoracic or lumbar spine. The needle diameters were 2.5 mm and 3.5 mm respectively ranging in length from 100 to 150 mm and were used to puncture the vertebral bodies to produce a tunnel for the polymethylmethacrylate (PMMA) injection. There was a disposable 10 ml medical injector inside the device to increase pressure in the spiral injector that is used to inject the PMMA (produced by Tianjin synthetic industrial institution).75 of meglumine diatrizoate was added to enhance the development of the PMMA under X-ray. The preparation ratio of the power (g) the liquid (ml) to the contrast agent (ml) was 3:2:1.

 

 

Prior to the operation eath patient was examined by X-ray a CT scan (computed tomographic ) or by MRI (magnetic resonance imaging ) to determine the location and number of vertebral bodies which involved a tumor the collapse of the vertebral bodies the degree of osteolytic lesion the integrity of the spinal cord compression. Examinations on the patient’s heart lung liver and kidney functions blood sugar PT and test for iodine allergy were conducted prior to the procedure. The patients were given analgesics 15 min before the operation. After determining the indication to operate the operations in the intervention operating room were conducted under the guidance of DSA. For the cervical spine : the patient was instructed to lie flat in a supine position with a pillow under his shoulder. The plane of the pathologically changed vertebral body on the screen of the DSA was selected on lateral fluoroscopy position. The puncture point between the trachea and the vertebral artery was determined according to the mark of the chosen plane. After performing local anesthesia the middle finger and the forefinger was  used to press the front edge of the vertebral body between the space of the trachea and the carotid artery which pushing the trachea towards the other side at the same time. The puncture needle was placed 0.5 to 1.0 cm to the medial side of the carotid artery. In-sert the needle as the needle and the sagittal plane of the vertebral body while maintaining a 15 to 20 degree angle. The needle tip was in 1/3 of the front edge of the vertebral body on lateral fluoroscopy position (Fig .1).The needle tip was at the center of the vertebral body or deviating to left or right 0.3 cm on the front fluoroscopy position (Fig .2). For the thoracic and lumbar spine : the patient was instructed to lie flat in the prostrate position. Punctured via the pedicle of vertebral arch approach measured the inclination degree of the pedicle of vertebral arch the distance of the spinal process of the puncture point the depth from puncture point to the pedicle of vertebral arch. The puncture point was placed 2 to 3 cm beside the spinal process and local anesthesia of 1 lidocaine was administed. When the puncture needle arrived at the bore cortex and the depth of the intrusion needle didn’t exceed the front of the pedicle of the vertebral arch on the front of fluoroscopy position the needle tip should be within the “buphthalmos” of fluoroscopy of the pedicle of the vertebral arch (Fig .3). When the puncture needle went through the bone cortex and entered the vertebral body on a lateral fluoroscopy position the puncture needle was slowly hammered into the 1/3 of the front of the pedicle of the vertebral arch.It showed that puncture needle tip had exceeded the center of the pedicle of the vertebral arch on the front fluoroscopy position. It is preferable to use puncture needle with a beveled needlepoint as it is easier to control the direction of needle while injecting the fluid. The bone around the puncture point at the sacroiliac joint was damaged most. After finishing the puncture the syringe piston was removed and 5 ml of contrast medium infused into the injection-tube. The circumfluence of the contrast medium was noted by the DSA. The pressure in the centra was depressed by sucking out the tumor and blood which remained in the centra. The bone cement was prepared using China-produced PMMA and non-ionic contrast medium. The bone cement was infused into the injection-tube and injected when the bone cement became like paste. The whole process of injection was supervised on a lateral fluoroscopy position to prevent the bone cement from leaking outside of the vertebral body (Fig .4). The point of the needle direction was continuously revolved in order to transfer the bone cement well while pushing the plunge. After injection the puncture needle was withdrawn to the bone cortex ed the syringe piston turned the puncture needle to prevent the bone cement from sticking it. The needle was pulled out before the bone cement hardened. The total volume of injected cement ranged from 2 to 9 ml. The average amounts were 2.5 ml for the cervical spine 5.5 ml for the thoracic spine  and 7.0 ml for the cervical vertebra.^[2] The patients were reexamined by CT 15 to 20 min after the injection when the polyreaction of the bone cement had completed (Fig .5 ).

 

 

We used a short-form health survey (SF-36) to survey of life ^[3]. The form included 11 items with each item including many questions. The score was calculated based on the answers chosen and the final score adjusted by a formula with a higher score representing healthier to patients. Among the items a score of no .1 3 4 7 8 and 11 referred to physical agility a score of no .5 6 9 and 10 referred mental status. The score of physical agility the score of mental status =the total score of quality of life.

 

 

The degree of the relief of bone pain was based on the evaluation of pain which was calculated as pain degree ×pain frequency. The degree of pain and frequency was based on the UICC standard. The degree of pain sorted into 5 classes i.e. 0 1 2 3 4^[4]. The patients’ degree of pain and frequency were written down when getting up and going to bed and the score of pain calculated. The evaluation of the analgesic effect and the standard classes of pain relief were :0 for no relief Ⅰfor light relief Ⅱfor moderate relief Ⅲ for high relief Ⅳ for complete relief.

 

SPSS 10.0 statistical software was used for statistical analysis. The t-test was used for measurement data and the X ²-test used for enumeration of the data.

 

 

The patients in the treated group were operated smoothly. There were 57 vertebral bodies injected via one side and 24 vertebral bodies injected via both sides. Regular chemotherapy was given to the patients after the operation and regular radiation therapy and chemotherapy were employed for the patients in the control group. Evaluation of the therapeutic effect was done subsequently.

 

 

According to the evaluation of quality of life by the SF-36 there was no significant difference in the quality of life between the 2 groups before treatment. After treatment the quality of life in the treatment group obviously improved whereas quality of life in the control group declined. A significant difference in the quality of life between the 2 groups is shown in Table 2 (P ＜0.05﹚.Bone pain was relieved in both groups after treatment but in the treated group bone pain stopped in 6 to 72 h post operation with an effective rate of 100. And the degree of pain relief was significantly higher than that of the control group (P ＜0.05 Table 2﹚.

 

 

All patients were given the follow-up survey for 12 months. During the follow-up period 5 patients died because of other organs complications in group A. The death rate was 9.1 (5 out of 55). Shift of the vertebral bodies was not found. There were changes in the physiological arch angulation and olisthe of vertebral bodies what had existed before treatment didn’t develop. There were no further vertebral body compressions spinal cord or never compressions on paraplegia. Treatment of the vertebral bodies permanently eliminated the pain. Thirteen patients died in group B showing a death rate of 23.6 (13 out of 55). Pathological compression fractures in the vertebral bodies occurred in 30 cases were complicated with group B paraplegia. The incidence rate of paraplegia was 21.8 (12 out of 55).

 

 

Six patients with a metastatic spinal tumor developed a pathological compression fracture after treatment with PVP and the PMMA leaked to the front of the vertebral bodies. Since there were no clinical symptoms no further treatment was needed. There were no complications of spinal cord compression pulmonary embolism and never root compression occurred.

 

 

The vertebral column is where metastatic bone tumor occur most frequently. At the metastatic site the tumor cells produce osteoclastic-activating factors which activate osteoclasts causing enhancement of the bone absorption and induction of bone lesions^[5]. The injury of the metastatic focus to the vertebral body and its accessories induce to a vertebral column pathological fracture causing the stability of the vertebral column to decline. This results in severe back pain even never function disorder and a predisposition to pathological fracture. Some mental symptoms such as depression and irritability may occur severely affecting the quality of life. With the development of tumor therapy more attention has been paid to the improvement of the quality of life which is a measurer of the therapeutic effect^[6]. There are many therapeutic methods treat to metastatic spinal tumors such as radiation therapy chemotherapy radioisotope therapy biphosphonates therapy analgesia therapy and palliative operations. Choice of a therapeutic method depends on the histological type of the primary tumor the nerve function situation before treatment the number of vertebral bodies involved the degree of spinal canal compromise the patient’s physical status the degree of pain and so on. The degree of pain relief can be more than 75 by radiation therapy but it takes 1 to 2 weeks to produce an effect. The biggest weakness of radiation therapy is that it does not resolve the problem of instability of the vertebral column caused by tumor damage but increases the danger of vertebral body collapse and never compression^[7]. A surgical operation is suitable for patients with spinal cord compression but it results in big wounds and many complication and is not suitable for nonadjacent multiple vertebral body metastatic tumors.

 

In recent years along with the rapid development of interventional techniques PVP has become one of the focuses in spinal surgery result in only small wounds and thus is gaining the attention of more surgeons^[9-12]. PVP is used in treating metastatic spinal tumor in our hospital as it is effective in relieving the patient’s pain and improving the quality of life. Both Cotton et al. and Cortet et al.^[14]reported that by treatment of metastatic vertebral body tumors with PVP the rate of eliminating pain and relieving pain significantly was 67.5 and 68.5 respectively whereas the rate of relieving pain partially was 30. The efficient rate of relieving pain in our research was 100. The location of the centra which were cured through PVP were not found any shift namely the change of the original physiological bend and the other abnormal change including angularity slide and so on did not go worse any more and it were not appeared that the symptoms included the centra were futher compressed the spinal cord or the never roots were subjected to press and lead to paralysis as well the cured centrums appeared the ache symptom again. So this indicates that the spinal column stability is good after PVP. Most of the vertebral bodies involved with a tumor were fulfilled uniformly by bone cement which could delay tumor development and provide constructional substitution and thus possibly prevent further lesion of vertebral bodies collapse and vertebral cord compression^[15]. In 6 patients with a metastatic spinal tumor pathological compression fractures developed after performing PVP. The PMMA leaked to the front of the vertebral bodies but there were no clinical symptoms and no other complications occurred. The results demonstrated that PVP is a safe operation resulting in only small wounds.

 

This study revealed the following : the most outstanding feature of the technique is to cure intractable pain caused by metastatic spinal tumor. The procedure improves the stability of the vertebral column and significantly improves quality of life. Performing the operation under the guidance of DSA can enhance its safety. Repeatedly sucking out the centra contents can effectively lower the pressure inside it and allow the bone cement to fill well. Use of a puncture needle with a beveled point allows better control of the direction of the needle during the procedure. Adjusting the needlepoint direction continuously while pushing in the bone cement permits good filling and reduces the leakage rate of the bone cement in summary we consider that PVP can relieve pain effectively caused by osteolytic metastatic spinal tumors. It can enhance the strength of the vertebral bodies and improve the stability of the vertebral column. It is a safe and easy operation causing only small wounds and is without a systemic toxic effect. It is suitable for multiple metastatic spinal tumors (Fig .67). Therefore PVP is an effective treatment for mestastatic spinal tumors. It will achieve a better therapeutic effect if combined with radiation therapy chemotherapy and other complex treatments. At present PVP is the most appropriate therapy for patients whose pathologic change from a metastatic spinal tumor result in a difficult excision and if there is no compression symptoms of the spinal cord and nerve roots.      

 

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[9] Galibert P Deramond H Rosat P et al. Preliminary note on the treatment of vertebral angioma by percutaneous acrylic vertebroplasty. Neurochirurgie198733:166-168.

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[13] Cotton A Dewatre F Cortet B et al. Percutaneous vertebroplasty for osteolytic metastases and myleoma:effects of the percentage of lesion filling and the leakage of methyl methacrylate at clinical follow-up. Radiology 1996200:525-530.

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