[Abstract] OBJECTIVE:To investigate the complications and preventive measures of percutaneous kyphoplasty (PKP) for osteoporotic vertebral compression fractures (OVCFs). METHODS: There were 110 patients with OVCFs treated with PKP at our hospital between 2004 and 2012, with a total of 126 vertebrae. Among them, 21 cases were male and 105 cases were female, aged 36-85 years, with a mean of 69 years. There were 100 single vertebral bodies, 10 double vertebral bodies and 2 triple vertebral bodies; all cases were determined preoperatively by MRI to determine the lesioned segment, and by X-ray and CT to understand the degree of vertebral compression and the posterior wall of the vertebral body. Among them, T4:1 case, T6:1 case, T7:1 case, T11:13 cases, T12:27 cases, L1:31 cases, L2:35 cases, L3:12 cases, and L4:5 cases. In this paper, we retrospectively summarized various complications in treatment and their occurrence ratio, analyzed their causes and preventive measures. Results: The total incidence of perioperative complications was 54%, 66 cases of cement leakage (52.4%), among which one patient with intracanal leakage developed high fever after surgery, and the symptoms disappeared after 1 week of symptomatic treatment without symptoms of nerve injury, while most of the other leaks occurred in the anterior leakage, and a few patients had endplate rupture leakage and posterior leakage. No pulmonary embolism occurred in all patients, no toxic reaction of bone cement, no arterial or nerve root injury due to puncture, one case of temporary spinal cord injury, one case of vertebral puncture error, one case of balloon rupture, one case of insignificant pain relief, and no case of postoperative infection. Conclusion: Bone cement leakage is the most common complication in PKP for OVCFS, and other complications occur less frequently. Strictly mastering the surgical indications, grasping the amount of bone cement filling and improving the surgical skills can significantly reduce the occurrence of complications.
【Key words】percutaneous perforator vertebroplasty; osteoporosis; thoracolumbar compression fracture; complications; prevention
The complications and preventions of percutaneous vertebral kyphoplasty for the treatment of the thoracic and lumbar osteoporotic compression fractures during the operation
Wang xi-san, Liu Cheng, Liu He, Yang Da-zhi, Hu Guang-xun, Li Li, Zeng Niang-hua. Department of the Orthopaedics, Nanshan Affiliated Hospital of Department of the Orthopaedics, Nanshan Affiliated Hospital of GuangdongMedicalCollege, Shenzhen 518052,China.
[Abstract] Objective: To discuss the complications of percutaneous kyphoplasty(PKP) for the osteoporotic compression fractures(OVCFs) in the treatment of the thoracic and lumbar vertebrae,and to investigate its caurses and preventions.Methods: from Jan. 2004 to Dec. 2012, the PKP or PKP combined with percutaneous vertebrobroplasty The PKP or PKP combined with percutaneous vertebroplasty (PVP) was performed on 126 vertebraes in 110 patients with thoracolumbar OVCFs. The average age was 69 years (range from 36 to 85).100 cases had single vertebra, 10 cases had double vertebras, 2 cases had 3 vertebras. determined the injured segment by MRI before the surgery, and we also made the fracture of the vertebras clearly by X ray and CT scan, including 1 in T4,1 in T6 We retrospectively analysed the causes of the complications, and try to solve them. Results: Perioperative complication was happened in 68 cases(54%), the leakage of the bone cement happened in 66 cases(52.4%): one of them had a high fever after the leakage happened behind the post-wall of the vertebra body, and it disappeared after one week with the relevant treating, there was no Most of the leakage happened in front of the vertebra body, few happened in the terminal plate, few happened behind the vertebral plate, and one of them had a high fever after the leakage happened behind the post-wall of the vertebra body, and it disappeared after one week with the relevant treating, there was no injury of the nerve. There was no pulmonary embolism, the bone cement toxic reaction wasn’t found in this team .There was no artery and nerve injury. One temporary spinal cord was happened, one case was punctured with a wrong vertebra, and ballon rupuure in one case. one case had less pain release, and no Conclusion: The bone cement leakage was the easiest happened complication associated with PKP in the treatment in OVCFs If we can grasp the operation indications for surgery, control the volume of the filling cement, improve the If we can grasp the operation indications for surgery, control the volume of the filling cement, improve the operation skill, we can reduce the rate of the complication.
[Key Words】 Percutaneous vertebral kyphoplasty; Osteoporotic ;Thoracolumbar compression fractures; Complication;Prevention
Percutaneous kyphoplasty (PKP) has been widely used in the treatment of osteoporotic vertebral compression fractures (OVCFs) since its first application in 1994 by Mark Reiley in the United States, OVCFs have been treated with good results, but many complications have been reported in the literature, which can lead to paralysis or even death in severe cases. According to foreign reports, the incidence of cement leakage alone can range from 6% to 70% [1-4], whereas in China, complications are often reported to be low, even about 1% in some cases. The authors took PKP for OVCFs in 110 patients with 126 vertebrae in our hospital from 2004 to 2012, and their complications and treatment experience are summarized as follows.
1. Clinical data
1.1 General data
From January 2004 to November 2011, 110 cases of thoracolumbar OVCFs with 126 vertebrae were treated in our hospital; 21 cases of 25 diseased vertebrae in men and 75 cases of 85 diseased vertebrae in women; the average age was 66.5 (36-85) years; 125 cases of fresh fracture and 1 case of old fracture,. All patients underwent X-ray, CT and MRI examinations before treatment and were proven to have fresh or old OVCFs, excluding primary tumors of the vertebral body as well as metastatic tumors, no signs and symptoms of spinal cord and nerve injury, no local infectious diseases, no dermatological diseases and abnormal coagulation mechanism diseases. The age of the patients ranged from 36 to 85 years, with a mean of 69 years. There were 100 patients with single vertebrae, 10 patients with double vertebrae, 2 patients with triple vertebrae, 109 patients with primary OVCFs, and 1 patient with secondary OVCFs (a patient with systemic lupus erythematosus), and the distribution characteristics of the specific lesioned vertebrae are shown in Figure 1. The duration of disease in all patients with fresh fractures ranged from 1 to 14 d, with an average of 5.2 ± 1.1 days, and the duration of disease in one patient with an old fracture was six months. Preoperative X-ray, CT examination and MRI examination of all patients with fresh fractures showed that the anterior wall of 126 vertebral bodies was fractured in 110 cases, and the posterior wall of vertebral bodies was fractured in 36 cases in combination, among which the posterior superior edge of vertebral bodies protruded mildly into the spinal canal in 8 cases, but there were no neurological symptoms. There were 28 compression fractures above Ⅲ° and 98 compression fractures from Ⅰ° to Ⅱ°. All 110 patients with 126 vertebral bodies were treated with PKP or PKP combined with PVP (if the effect of unilateral PKP was unsatisfactory, the other side was treated with PVP). A characteristic of this group of cases is that some patients with relative contraindications to surgery were included in the treatment.
1.2 Surgical method
Patients were placed under local anesthesia with respiratory and cardiac monitoring in a prone position with pillows on the cervicothorax and hip respectively, and the abdomen was suspended as much as possible, firstly, to use the position for repositioning, and secondly, because most of all patients were elderly, abdominal suspension could reduce abdominal pressure and avoid the effect on respiration and blood pressure. Preoperatively, iodine allergy test was performed, and 75-100 mg of dulcolax was given intramuscularly before positioning the patients according to their weight and age, respectively, to reduce pain during moving and during surgery. After disinfecting the sheet, the patient was positioned under DSA surveillance to determine the location of the lesion and puncture, and then local anesthesia was performed with 2% lidocaine diluted twice. After the anesthesia was effective, the position of the projection of the vertebral arch on the skin surface of the lumbar back was determined under fluoroscopy, then puncture was performed, the working sleeve was fixed, the working channel was established, the working channel was dilated, the balloon was placed, the vertebral body was dilated, the bone cement was filled, the bone cement was polymerized, the working sleeve was removed, and the operation was completed.
1.3 Postoperative treatment
After the operation, patients were instructed to rest in bed, lying flat and pressing the wound for 2 hours, and then they could move freely in bed without antibiotics if there were no special circumstances. On the second day after surgery, patients were instructed to move on the ground under the protection of waist circumference. If the patient’s pain relief is not satisfactory, the bed resting time can be extended appropriately. If there is no special discomfort, the patient can be discharged from the hospital 3-5 d after surgery and is instructed to take out-of-hospital anti-osteoporosis treatment.
2. Results
All 110 vertebrae of 126 patients were treated with unilateral PKP or PKP on one side plus PVP on the other side under DSA surveillance in our radiology department. Among them, 100 vertebrae were treated with unilateral PKP and 26 vertebrae were treated with PKP plus PVP, and the complications were characterized as follows.
(1) Leakage of bone cement: the incidence of extra-vertebral leakage of bone cement was the highest in this group of cases, with 66 cases and an incidence of about 52.4%, of which 31 cases were leakage from the anterior edge of the vertebral body, 20 cases were leakage from the anterior vertebral vein, 7 cases were leakage from the posterior vertebral vein, 15 cases were leakage from the upper endplate, 5 cases were leakage from the posterior wall of the vertebral body, 3 cases were leakage from the posterior vertebral plate, 2 cases showed trailing phenomenon outside the vertebral plate, and no leakage occurred at the intervertebral There was no leakage at the foramen. One case of leakage anterior to the posterior longitudinal ligament in the posterior aspect of the vertebral body, but there were no symptoms of neuromuscular injury and the patient’s pain symptoms disappeared significantly, and part of the leakage is shown in the following figure (a-i).
a posterior leakage of the vertebral plate b lateral leakage of the vertebral body c anterior leakage of the vertebral vein
d leakage from the inferior endplate e leakage from the anterior border of the vertebral body f leakage from the anterior posterior longitudinal ligament in the vertebral canal
g upper endplate leakage leakage h posterior mixed leakage i lateral posterior venous leakage
(2) Spinal cord injury: a patient with postoperative spinal cord compression symptoms and subarachnoid hemorrhage on MRI was suspected to be caused by an intravertebral canal misdirection injury to the dural sac, and the symptoms recovered after active symptomatic treatment.
(3) Mislocalization error leading to misintervention: in one case, due to mislocalization, an adjacent old fractured vertebral body was mistaken for a diseased vertebral body, and the patient’s symptoms recovered insignificantly after surgery; the X-ray was reviewed and the fractured vertebral body was found to be untreated, and the patient recovered well after the second operation for bone cement infusion of the diseased vertebral body.
(4) Insignificant relief of lumbar pain: one patient had insignificant relief of lumbar pain after surgery. (4) Considering that it may be due to the patient’s heavy weight, young age, insignificant osteoporosis and unsatisfactory recovery of vertebral body height after balloon expansion, resulting in insignificant pain relief, which belongs to the selection of surgical indications.
(5) Balloon rupture: there was one case of balloon rupture in this group, which was considered to be related to the excessive speed of pressurization and poor polishing of bony working channels in the vertebral body, and the patient did not show any uncomfortable symptoms and recovered well after surgery.
No pulmonary embolism and vascular embolism of important organs, no hemopneumothorax, large vessel injury and irreversible spinal cord injury occurred in all cases; no obvious toxic reaction of bone cement was found, and there were no cases of postoperative infection.
3. Discussion
PKP is widely used in the clinical treatment of OVCFs due to its advantages of less trauma, faster recovery, better results, lower risk, shorter bed rest time for patients, and significant reduction of bed rest complications. However, if the surgical indications are not properly mastered, the operation technique is not skilled, and the operation experience is not rich, many complications can occur, which can be life-threatening in serious cases [5]. The possible complications during the surgical operation and some operational experiences are analyzed as follows.
3.1 Bone cement leakage
Bone cement leakage should be the most frequent complication in all PKP punctures, and reports vary. Yang Yimin et al [6] reported that the leakage rate of bone cement was 13.2%, while Sui Fuger et al [7] reported a leakage rate of 11.3% in a case of 115 cases. Becker et al [8] reviewed 100 cases of PKP, and the leakage rate of bone cement was 31%. The leakage rate of bone cement in the present group of cases was 54%, which is much higher than most of the reports in China and close to some of the foreign reports. It was considered that it was mainly due to several reasons: 1). Unskilled operation technique in the early stage; 2). Broad indications for treatment, which included some patients with relative contraindications to surgery, such as severe compression fractures of III°-IV° and posterior wall rupture of the vertebral body; 3). High pressure during balloon expansion, resulting in fractures of the anterior edge of the vertebral body or the upper and lower endplates; 4). Excessive pursuit of the amount of bone cement infusion; 5). Excessive speed of bone cement infusion, which exceeds the volume of space for balloon expansion, resulting in spillage of bone cement; 6). Bone cement modulation with too thin viscosity and poor adhesion, premature injection and leakage.
Therefore, according to the above-mentioned reasons, the following aspects can be paid attention to during the treatment to reduce both bone cement leakage: 1). Improve the operation skills, carefully study the X-ray, CT film and MRI film before operation, choose the appropriate puncture point according to the degree and site of fracture, and avoid the fracture line as much as possible; 2). Strictly grasp the indications for surgery, and for some patients with relative contraindications to surgery, attention should be paid to the operation according to different situations. barr et al [9] considered that compression degree in the thoracic spine over 50% and in the lumbar spine over 75% is not suitable for PVP treatment. Sui Fuge et al [7] prevented leakage in patients with anterior or posterior vertebral wall rupture by placing crushed gelatin sponges in the injection channel. In the treatment of patients with Ⅲ° to Ⅳ° compression fractures and fractures of the anterior or posterior edges of the vertebral body without symptoms of neurological injury, we mainly achieve prevention by controlling the puncture location and depth, mastering the timing of cement injection (choosing to inject when the viscosity is high), and the appropriate injection volume, while always monitoring through continuous fluoroscopy during injection; 3). Control the pressure of the balloon when performing vertebral body expansion. According to Yang Huilin et al [10], the intraoperative balloon pressure should not exceed 300 Psi, while we generally control the pressure within 220 Psi and perform intermittent expansion with continuous fluoroscopy to prevent rupture of the anterior edge of the vertebral body or the upper and lower endplates; 4). The amount of bone cement injection is properly controlled. Baroud et al [11] concluded from their study that bone cement leakage was positively correlated with the injected dose. Previously, it was believed that satisfactory results could be obtained by injecting bone cement up to 3.5 ml in the thoracic spine and up to 5 ml in the lumbar spine. belkoff et al [12] concluded from a study of cadaveric specimens that the injection volumes for the thoracic and lumbar spine were 2.5 ml and 4.4 ml, respectively. while we believe that the injection volume should be decided according to the degree of osteoporosis of the patient, the viscosity of the bone cement and the dispersion in the vertebral body, rather than fixed standard, as long as the injection volume of bone cement is not pursued blindly; 5). Inject the bone cement slowly, avoiding excessive speed, and under continuous fluoroscopy; 6). Master the timing of bone cement injection. If the degree of osteoporosis is heavy, the bone cement can be injected in a more viscous state; if the degree of osteoporosis is mild, it can be injected during the drawing period; if the anterior edge of the vertebral body or the end plate is broken, try to inject slowly with a pusher in a more viscous state. It is best to perform continuous fluoroscopy during injection, and it is important not to pursue the injection volume of bone cement excessively to avoid spillage.
3.2 Spinal cord and nerve root injury
A case of spinal cord injury in this group was fractured in the thoracic 10 segment, which was considered to be caused by puncture injury to the dural sac, resulting in subdural hemorrhage compressing the spinal cord. The causes of spinal cord and nerve root injury are summarized in the following two points: 1). Puncture factors. This is due to the inward position of the puncture point during puncture or the puncture angle being too abducted; 2). Leakage of bone cement. Fracture of the posterior edge of the vertebral body, or damage to the medial wall of the pedicle during puncture, resulting in leakage of bone cement backward into the spinal canal to a certain extent, damaging the spinal cord or nerve roots and producing symptoms. Such complications can be prevented and treated by improving the technique and controlling the viscosity of the bone cement. During the operation, the angle of the bulb tube is adjusted under fluoroscopy so that the projections of the upper and lower margins of the vertebrae adjacent to the diseased vertebrae overlap into a line in the ortho-lateral position, and the spinous process of the diseased vertebrae is in the middle of the vertebral body in the ortho-slice. For the left puncture, the puncture needle was selected at the 10 o’clock position of the arch projection, and for the right puncture, the 2 o’clock position of the arch projection was selected. After puncture, the tip projection of the orthopantomogram overlaps with the spinous process, and the lateral position is 5 mm from the anterior edge of the vertebral body. The upper and lower positions are determined according to the specific situation of the fracture, and generally speaking, if there is a break in the upper endplate, the puncture is as far from the middle of the vertebral body as possible.
3.3 Lumbar pain relief is not obvious
In one of the cases in this group, the relief of lumbar pain after surgery was not obvious, which was considered to be due to the patient’s young age (57 years old), heavy weight (80 Kg), insignificant osteoporosis, and unsatisfactory recovery of vertebral body height on postoperative radiographs. Therefore, the choice of surgical indications is an important factor in determining the success of surgery. We generally believe that the severity of osteoporosis is a key factor in determining whether PKP treatment can be performed. If the degree of osteoporosis is not severe, it is better to perform nail bar system internal fixation treatment instead of blindly choosing PKP.
3.4 Positioning error
In one patient in this group, the adjacent vertebra of the diseased vertebra was an old fracture with heavy osteoporosis, and the vertebra was difficult to identify under fluoroscopy, and the puncture mistakenly penetrated the old fractured vertebra, resulting in unsatisfactory postoperative pain relief, and the problem was found on review of the postoperative X-ray, and the symptoms were relieved after re-treatment. Therefore, careful preoperative film reading, understanding the anatomical characteristics of the diseased vertebrae, performing MRI examination to identify the responsible vertebrae, and accurate intraoperative positioning can completely avoid puncture errors.
3.5 Balloon rupture
Sui Fuge et al [7] reported 3 cases of balloon rupture in an analysis of 115 patients, with an incidence of 2.6%; Liebschner et al [13] reported 70 vertebrae in 30 cases, with 14 balloon ruptures, with an incidence of 20%. In our group, balloon rupture occurred in only one patient treated early, accounting for 0.8%. Analysis of the causes of balloon rupture may be the following: 1. partly due to high balloon pressure; 2. fatigue rupture due to repeated use of multivertebral expansion balloons; 3. bone spurs in the vertebral body piercing the balloon. Therefore, intraoperative repeated grinding of the working channel with a flat-tipped drill, intermittent pressurization during expansion, control of the maximum pressure within 220 Psi, and avoidance of repeated use can basically avoid the occurrence of such problems.
3.6 Toxic reactions of bone cement
There are few reports about the toxicity of bone cement, and Yang Yimin [6] et al. reported that some patients had transient chest tightness, shortness of breath and blood pressure drop during the operation, which were considered to be the toxic reaction of bone cement, and the injection was stopped immediately, and the symptoms disappeared after oxygen, fluid and dexamethasone was injected quietly. Some patients in this group may experience transient increase in blood pressure, which is considered to be caused by the sympathetic nerve stimulation by the polymerization heat generated by the bone cement. The patient’s sensation and blood pressure changes can be closely observed during the treatment, and if there is any discomfort, the injection can be stopped at any time and symptomatic treatment can be given, which usually does not produce serious consequences.
3.7 Pulmonary embolism and other complications
Pulmonary embolism should be the most serious complication of PKP treatment, although the incidence is low, the consequences are more serious. Hulme et al [14] reported that the incidence of pulmonary embolism in PKP was 0.01%, and no pulmonary embolism occurred in this study. Pulmonary embolism should be completely avoided by controlling the viscosity of the bone cement and the timing of injection during operation. There are other complications of local hematoma after puncture, which can be reduced by paying attention to improving the puncture technique and postoperative compression for hemostasis because they do not have serious consequences.
In conclusion, the PKP technique can effectively treat patients with OVCFs, and with the selection of appropriate surgical indications and improved surgical technique, surgical complications can be reduced and surgical risks reduced.
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