PainStracts | September 2018 - Module No. 1
Kyphoplasty for osteoporotic vertebral fractures with posterior wall injury.
Author(s): Abdelgawaad, et al.
Journal: The Spine Journal. 2018; 18: 1143-1148. 33 references.
Reprint: Ahmed Shawky Abdelgawaad, MD, Spine Center, Helios Klinikum Erfurt, Nordhaeuser street 74, 99089, Germany. E-mail: firstname.lastname@example.org.
Faculty Disclosure: Abstracted by N Walea, who has nothing to disclose.
Objective: Review and evaluate the latest advances and newest information in the area of the Percutaneous kyphoplasty; Review and evaluate the latest advances and newest information in the area of Diseases of the Osseous System
Kyphoplasty is an appropriate treatment for osteoporotic vertebral body fractures, but there is a concern that if the cement leaks posteriorly, it could affect the spinal canal and cord. Posterior wall fractures are considered a relative contraindication for this procedure for this reason. This study did not find any posterior leaks in their total of 98 kyphoplasties performed. Potentially, this may be due to an intact posterior longitudinal ligament that would inhibit cement leaking posteriorly. While their modified technique may reduce the risk of leakage, be aware that the study may simply not be powered to show the incidence.
Classification: IV.M. Kyphoplasty; III.F. Osteoporosis
Transpedicular cement augmentation procedures (vertebroplasty and kyphoplasty) are standard procedures for the treatment of osteoporotic vertebral fractures. Cement leakage is a common complication of percutaneous vertebral cement augmentation techniques. Posterior wall defects are relative, but not absolute, contraindications for balloon kyphoplasty (BKP) because of the risk of cement leakage into the spinal canal and the possible subsequent neurological complications. There are currently no guidelines regarding this issue.
For this study, between December 2012 and December 2016, 82 patients with 98 osteoporotic fractures of the thoracic or lumbar vertebrae with posterior wall cortical injures were enrolled. The patients were divided into two groups Group A, which consisted of 81 (82.65%) T2-L2 vertebral fractures, and Group B, with consisted of 17 (17.35%) L3-L5 vertebral fractures. This grouping of the data was essential as the sagittal measurements varied from zero to kyphotic degrees in Group A and from zero to lordotic degrees in Group B.
All kyphoplasty procedures were performed under general anesthesia with the patient in the prone position, using fluoroscopy with one image intensifier that was rotated through 90°. Small-sized balloon were placed inside the anterior two-thirds of the vertebral body. The size of the balloon tamps differed according to the vertebral region. The balloons were then slowly inflated, and the volumes of the balloons noted. The high-viscosity polymethylmethacrylate cement was mixed and allowed to set until it was an appropriate, doughy viscosity before injection. The balloons were then deflated and removed. The volume of the cement injected was equal to or less than the inflation volume of the balloon tamps.
The vertebral bodies were scored for cement leaks. Sagittal orientation was determined by the Cobb angle and the vertebral wedge angle.
The mean preoperative Cobb angle in Group A was +15.17°. This improved to +9.37° post BKP. The mean vertebral wedge angle showed good improvement from +11.22° preoperatively to +5.03° postoperatively. The mean anterior vertebral height increased from 17.53 mm preoperatively to 22.43 postoperatively.
Group B showed an improvement in the mean lordosis of the fractured vertebrae from a mean Cobb angle of -10.03° to -13.72°. The mean vertebral wedge angle improved from 2.72° to 0.52°. Similarly, the mean anterior vertebral height of the fractured lumbar vertebrae increased from 25.16 to 27.72 mm. The average volume of cement injected in one level of kyphoplasty was 5.7+2.1 mL.
There were no leaks into the spinal canal in any case, but there were asymptomatic leaks (cortical, discal, or vascular), seen in 22 vertebrae out of the 98 (22.45%). There were no neurologic complications in the study population.
The mean preoperative visual analog pain scale was 8.1 (+1.3) which improved to 2.3 (+1.1) on the third day postoperatively.
In this study, some modifications of the technique were used. Large void volume was created using the balloon, and the injected cement was either equal to or smaller than that void. Small-size balloons were positioned in the anterior two-thirds of the vertebrae, and high-viscosity cement in a dough state was injected in increments. These procedures might explain the absence of any leak into the spinal canal and the lower asymptomatic leaks reported in this study. Injecting an amount of cement equal to or less than the void produced by the balloon succeeded in preventing leak into the canal but was still adequate to induce an appreciable correction of the vertebral deformity. This is shown by the improvement in the Cobb angle, the vertebral wedge angle, and the anterior vertebral height.
The data from this study suggest that posterior wall defects in low-energy osteoporotic fractures represent no contraindication for kyphoplasty. Anterior positioning of the balloon, use of high-viscosity cement in a doughy state, and strict adherence to fill the void with the same volume achieved with the balloon or even less are presumably all factors that can help to decrease the incidence of cement leakage.