Correlative Factor Analysis On The Complications Percutaneous Kyphoplasty In The Treatment Of Osteoporotic Vertebral Compression Fractures

Objective: Over the past decade, percutaneous kyphoplasty (PKP) has been progressively used to treat osteoporotic vertebral compression fractures (OVCFs).The procedure of PKP can stabilize the fracture, restore the vertebral body height, and reduce the sagittal alignment of the spine. Multiple studies have documented the effectiveness of the PKP in relieving pain caused by OVCFs. Cement leaks are important and contribute to a substantial piece of the clinical complications that have been reported. Although it is generally of no clinical significance, cement leakage into the spinal canal or neural foramina may cause new symptoms and require decompressive surgery, cement leakage into the intervertebral space may increase the risk of subsequent fractures of adjacent vertebral bodies. For this reason, minimizing the cement leaks should be a goal with all cement augmentation procedures. However, a review of the current literature shows less efforts to address the correlative factors affecting the complications resulting from cement leakage. The purpose of the present study was to define the correlative factors associated with complications of PKP in the treatment of OVCFs and appropriate improvement in surgical technique will be made accordingly to reduce the risk of complications.Methods: 71 patients with 171 vertebral compression fractures were treated by PKP and were retrospectively analyzed.The treatment efficacy was assessed by the change in vertebral body height,Cobb angle, visual analogue scale(VAS) and Oswestry functional score at preoperative,postoperative and the end of follow-up.All the complications were recorded,and then to explore the correlative factors affecting the complications. Preoperative computed tomographic examination was used to evaluate the integrality of vertebral body wall. All treated vertebrae were divided into acute or subacute stage based on the changes observed in MRI signal intensity between T1WI, T2WI, and STIR. Acute Stage : Preoperative MRI revealed low signal intensity on T1WI, and high signal intensity on T2WI and STIR in comparison to normal vertebrae.The signal intensity is uniformity. Subacute Stage: Preoperative MRI demonstrated plaque, punctiform, or strip-shaped areas indicative of low signal intensity on T1WI, and high signal intensity on T2WI and STIR as compared with normal vertebrae. The signal intensity is not uniformity. Preoperative and postoperative radiographs consisting of anteroposterior and lateral views were obtained and analyzed to quantify the changes in vertebral body height and sagittal alignment. The heights were measured at the anterior and middle portions of the vertebral body. The mean value of both sides was calculated and expressed as the vertebral body height. Sagittal alignment across the fractured level was calculated using the Cobb technique: measurements were taken from the superior end plate of the vertebra one level above the treated vertebra to the inferior end plate of the vertebral body one level below the treated vertebra. When nonadjacent levels were treated in a patient, separate Cobb angles were measured for each treated level. If adjacent level vertebral fractures were treated, a single Cobb angle measurement across the treated levels was performed. Complications were recorded according to imaging examination and patients were divided into cement leakage group and no cement leakage group to discover the difference, if there was any, in the following factors: preoperative vertebral body height, preoperative Cobb angle, injected cement volume, freshness of vertebral fracture, operative approach, vertebral body wall integrality, and the location of operative vertebrae.Results: All the cases had rapid and significant improvement in back pain following percutaneous kyphoplasty. Seventeen (9.94%) vertebral bodies had cement leakage.Of the total,the cement leak into the paravertebral, intervertebral space,channel of needling insertion and spinal canal in 7, 6, 3 and 1 cases respectively.Four cases(5.63%) had lung-related complications, one of them was confirmed to pulmonary embolism caused by cement leakage. During the follow-up we found nine recurrence vertebral fractures in six cases(8.45%) including six adjacent vertebral bodies.Univariate analysis showed that the preoperative vertebral body height,injected cement volume and vertebral body wall incompetence were significantly different between the cement leakage group and no cement leakage group(P<0.05).In contrast, there's no significantly different for the preoperative Cobb angle,freshness of vertebral fracture,location of operative vertebrae and operative approach between the two groups(P>0.05).Multiple logistic regression analysis showed that the injected cement volume(P<0.01,OR=3.105,95%CI=1.674–5.759) and vertebral body wall incompetence(P<0.01,OR=11.960,95%CI=3.512–40.729) were the predominant variable associated with the complications resulted from cement leakage.The patients who had a past history of pulmonary diseases were proned to occur lung-related complicationsConclusions: PKP is an effective treatment for OCVFs. However, cement extravasation occurs frequently during the procedure. The cement viscosity, injected cement volume, and the vertebral body wall incompetence were the critical factors affecting the complications resulting from cement leakage. The patients who had a past history of pulmonary diseases were prone to lung-related complications.We must pay more attention to these important factors during the PKP procedure and the improvement of surgical technique is the capital factor that may reduce the complications in the PKP.