Craneoplastía con implante de polimetilmetacrilato (PMMA)para corregir secuela de trauma. Reporte de caso / Craneoplasty with a polymethylmethacrylate (PMMA) Implant to correct trauma sequel. A case report

Introducción: los defectos del cráneo y las anomalías del hueso craneofacial que requie-ren reconstrucción son comunes en una variedad de procedimientos neuroquirúrgicos. Después de una craniectomía o de fracturas craneofaciales posteriores a traumatismos cráneoencefálicos, los pacientes pueden desarrollar defectos cosméticos importantes. Algunos de estos son la depresión de la piel y un defecto de hundimiento que lleva a una apariencia asimétrica de la cabeza, sin dejar de lado las repercusiones físicas, neu-rológicas y psicológicas que estas lesiones conllevan. La reconstrucción craneofacial y la craneoplastía tienen una larga historia, pero las nuevas técnicas quirúrgicas y una multitud de opciones de materiales han impulsado recientemente el avance en esta área. Los implantes de polimetilmetacrilato (PMMA) han demostrado ser estables, bio-compatibles, no conductores, radiotransparentes y de bajo costo. Es así que se pueden colocar y modificar fácilmente, con lo que se elimina la morbilidad del sitio donante. Presentación del caso: en este artículo presentamos un caso de craneoplastía de defec-to frontal, posterior a traumatismo, cuya reconstrucción fue realizada mediante una prótesis de polimetilmetacrilato (PMMA) en el Hospital General Xoco de la Cuidad de México. Conclusión: se reporta la reducción del tiempo quirúrgico, además de un costo de la prótesis accesible para el paciente; de esta manera, se obtuvieron resultados sa-tisfactorios y mejoras en el contorno estético facial, en tanto se permitió cobertura y protección para el tejido encefálico.

Introduction: Skull defects and craniofacial bone abnormalities that require reconstruction are common in a variety of neurosurgical procedures. After craniectomy or craniofacial fractures following cranioencephalic trauma, patients can develop important cosmetic defects, such as depression of the skin and a sunken flap that can lead to an asymmetrical appearance of the head, without neglecting the physical and psychological repercussions. neurological that these injuries carry. Craniofacial reconstruction and cranioplasty have a long history, but new surgical techniques and a multitude of material options have recently fueled progress in this area. Polymethylmethacrylate (PMMA) implants have proven to be stable, biocompatible, non-conductive, radiolucent, and inexpensive. They can be easily placed and modified and the morbidity of the donor site is eliminated. Clinical case: In this article, we present a case of frontal defect cranioplasty after trauma performed using a polymethylmethacrylate (PMMA) prosthesis at the General Hospital Xoco in Mexico City. Conslusion: The surgical time could be reduced, in addition to the cost of the prosthesis. It was accessible to the patient and obtained satisfactory results such as improvements in the facial aesthetic contour and obtained coverage and protection for the brain tissue.

Vertebroplasty for the Treatment of Painful Osteoporotic Compression Fractures

PURPOSE: To evaluate results regarding pain relief, spinal stabilization, and complication after treatment with percutaneous vertebroplasty. MATERIALS AND METHODS: 108 patients (12 men, 96 women; aged 42~84 years) underwent 156 percutaneous injections of surgical cement into a vertebra (vertebroplasty) with fluoroscopic guidance in 119 procedures. All patients had severe pain,osteoporotic fractures and had failed medical therapy. Immediate and long-term pain response, spinal stability, and complications were evaluated. Assessment criteria were the changes over time (Days 3, 30, 90, 180) in visual analogue scale (VAS: 0~100 mm) and McGill-Melzack scoring system. The height of vertebral body was checked at three portions (anterior, middle, posterior) with lateral view of plain radiographs. RESULTS: A statistically significant decrease of both VAS and McGill-Melzack scoring system was observed at Day 3. The results were also significant at Days 30, 90, and 180 both scales. We observed no adverse event, but 26 vertebral fractures had occured in the adjacent level during 12 months of follow-up. The leakage of cement was observed in 57 vertebral bodies (36.5%). But there was no neurological symptoms associated with cement leakage. The vertebral body height was increased after vertebroplasty. CONCLUSION: Vertebroplasty is safe and effective, and have a useful role in the treatment of painful osteoporotic vertebral compression fractures that do not respond to conventional treatments. Continuous management of osteoporosis and patient education is mandantory to prevent subsequent fracture of the adjacent vertebral bodies.

Percutaneous Vertebroplasty in the Treatment of Senile Osteoporotic Vertebral Body Compression Fractures: Treatment Efficacy and Complications

BACKGROUNDS: The purpose of this study is to clarify therapeutic efficacy of percutaneous vertebroplasty(PVP) using polymethylmethacrylate(PMMA) for the osteoporotic compression fractures of the spine and to define the complications following the procedures. METHODS: The authors retrospectively analyzed the clinical outcome of 51 consecutive patients with recent osteoporotic compression fractures undergone PVP between January, 2000 and December, 2001. We reviewed medical records, radiographic findings, and telephone questionaires. The clinical outcomes were categorized by visual analogue scale(VAS). RESULTS: The mean age of the patients was 70.2 years old(range, 60~84) and the male/female ratio was 9:42(17.6%:82.4%). Mean duration of symptom was 2.75 months(0.25~12). Mean follow up periods were 12.2 months(5~27). Among the 63 treated segments, most of them were thoracolumbar junction(69.8%, 44/63) and treated via bipedicular route(bipedicular/unipedicular: 47/16). Thirty-eight patients showed complete or partial relief of pain(82.6%). Age, sex, duration of symptom, number of involved segments, and approach(uni-/bipedicular) had no statistical significance to clinical outcome. Nonetheless leakage of acrylic cement was noted in 37 patients(72.5%), most of them were asymptomatic. The complications were 4 symptomatic leakages(4 transient radicular pain), 1 pulmonary embolisms, and 1 fractured acrylic cement. CONCLUSION: PVP using PMMA is a minimally invasive, safe and effective treatment modality providing primary stability and prompt pain relief for the osteoporotic vertebral compression fractures. As most of the complications are related with leakage of acrylic cement, preoperative CT scan, vertebral phlebography and fluoroscopic guidance are mandatory as well as cautious injection of adequate amount of PMMA.

Pulmonary Embolism after Percutaneous Vertebroplasty with Polymethylmethacrylate: Case Report

We present a case with rare complication of percutaneous vertebroplasty with polymethylmethacrylate (PMMA). A pulmonary embolus was detected in a 79-year-old woman with osteoporotic compression fracture after percutaneous verteroplasty. Chest radiography, computed tomography, and ventilation perfusion lung scan con-firmed pulmonary infarction and the presence of PMMA in the pulmonary arteries. She was treated with anticoagulants and responded favorably. Although venous leakage of PMMA has shown to be not uncommon, only a few cases of symptomatic pulmonary embolism have been reported. Adequate preparation of PMMA, optimal injection technique, and confirmation with biplane fluoroscopy are mandatory to minimize this type of complication.

Barrier Techniques for Spinal Cord Protection from Thermal Injury in Polymethylmethacrylate Reconstruction of Vertebral Body:Experimental and Theoretical Analyses

OBJECTIVES: Polymethylmethacrylate(PMMA) is often used to reconstruct the spine after total corpectomy, but the exothermic curing of liquid PMMA poses a risk of thermal injury to the spinal cord. The purposes of this study are to analyze the heat blocking effect of pre-polymerized PMMA sheet in the corpectomy model and to establish the minimal thickness of PMMA sheet to protect the spinal cord from the thermal injury during PMMA cementation of vertebral body. MATERIALS AND METHODS: An experimental fixture was fabricated with dimensions similar to those of a T12 corpectomy defect. Sixty milliliters of liquid PMMA were poured into the fixture, and temperature recordings were obtained at the center of the curing PMMA mass and on the undersurface(representing the spinal cord surface) of a pre-polymerized PMMA sheet of variable thickness(group 1:0mm, group 2:5mm, or group 3:8mm). Six replicates were tested for each barrier thickness group. RESULTS: Consistent temperatures(106.8+/-3.9degreesC) at center of the curing PMMA mass in eighteen experiments confirmed the reproducibility of the experimental fixture. Peak temperatures on the spinal cord surface were 47.3degreesC in group 2, and 43.3degreesC in group 3, compared with 60.0degreesC in group 1(p<0.00005). So pre-polymerized PMMA provided statistically significant protection from heat transfer. The difference of peak temperature between theoretical and experimental value was less than 1%, while the predicted time was within 35% of experimental values. The data from the theoretical model indicate that a 10mm barrier of PMMA should protect the spinal cord from temperatures greater than 39degreesC(the threshold for thermal injury in the spinal cord). CONCLUSION: These results suggest that pre-polymerized PMMA sheet of 10mm thickness may protect the spinal cord from the thermal injury during PMMA reconstruction of vertebral body.

A Biomechanical Analysis of Surgical Procedures for Osteonecrosis of the Femoral Head using Three-Dimensional Finite Element Method: A Parametrical Analysis by Varying Physiological Loading Conditions / 대한정형외과연구학회지

Many operative procedures for osteonecrosis of the femoral head(ONFH) have been proposed, but their clinical results remain controversial to many clinicians. Recently, a new surgical procedure that incorporates cementation with polymethylmethacrylate(PMMA) after core drilling has been tried clinically. In this study, a finite element method (FEM) was employed to analyze and compare various surgical procedures of ONFH to provide a biomechanical insight by varying physiological loading conditions. Our finite element models were constructed for this purpose they included normal, necrotic, core decompressed, fibular bone grafted, and cementation models. The extent of necrotic region was determined based upon the average CT-scan data from 10 patients. The physiological load directions and magnitudes during the gait cycle were selected at the stage of heel-strike, toe-off, and average stance. The von Mises stresses were calculated and volumetric percentages of the necrotic region under different levels of stresses were analyzed for each model. Our results indicated that there were substantial increase of the necrotic region subjected to the high stress level (beyond 11 MPa) and decrease in the low stress level (below 5 MPa) with the core decompression model, an indication of a malignant stress transfer pattern. On the other hand, the exact opposite pattern of stress transfer was noted with the fibular bone graft and cementation methods suggesting that they could provide structural integrity within the necrotic region.