Potential Hazards of Vertebroplasty
Vertebroplasty is indicated to treat pain from fractures, tumors, or metastasis of the vertebrae; however, since the injection of cement is done close to the spinal cord and nerve roots, it presents a potential hazard. Three cases in which injection of polymethyl-methacrylate (PMMA) was unintentionally made inside the dural sac are described.
Vertebroplasty is a procedure that consists of injecting a semi liquid cement-like material, polymethy methacrylate (PMMA), into the body of collapsed, fractured vertebrae. As in hip prosthesis procedures, reconstruction of anterior osteoporotic defects of the vertebral column are conducted by filling the compressed spongious bone, or the erosive lesions from metastases to the vertebral body, or from extensive hemangiomas.1-3 A properly executed injection of PMMA in the vertebral body is shown in Figure 1. The popularity of vertebroplasty seems justified as it reduces the spinal pain, and, in some cases, the accompanying radiculopathy. Advantages of this material are its flexibility in the mixing stage, its relatively low cost, it is biocompatible, low water absorption, and a high resistance to aging with sufficient stability to tolerate sterilization by autoclaving or by gamma radiation.2,4 The physical properties of this material can make it dangerous when inappropriately used, especially for those that are unfamiliar with handling it properly before it solidifies, or when erroneously applied. Three cases of incidental intrathecal injection of this substance that resulted in neurological deficit and arachnoiditis are reported.
The first two cases were middle age female patients with vertebral fractures from osteoporosis, the third case was a man injured in a work accident that resulted in compressed fractures of L2 and L3. In each instance, neither confirmatory aspiration, nor test doses were given before the cement was injected. Severe neurological deficits resulted in each case corresponding with the site of needle entry and the site where the cement was found in the dural sac.
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