DSpace Repository :: Browsing by Author "Silva, Álvaro"

Browsing by Author "Silva, Álvaro"

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Clinical Outcome and Histological Findings After Induced Leakage of PMMA Loaded With Methotrexate and Cisplatin During Vertebroplasty: Experimental Model in Pigs
(2021) Silva, Álvaro; Llombart, Rafael; Gallegos, Marcela; Villas, Carlos; Olmos, Matías
Study design: Animal experimental model. Objective: To study the clinical behavior and histological changes in the spinal cord, nerve roots and perivertebral muscles of the spine after induced leakage of polymethylmethacrylate (PMMA) loaded with antiblastic drugs during vertebroplasty in an animal model of pigs. Methods: We performed vertebroplasty on 25 pigs. The animals were divided into 3 groups: vertebroplasty with PMMA alone (control group), vertebroplasty with PMMA loaded with methotrexate (MTX) and vertebroplasty with PMMA loaded with cisplatin (CYS). At 2 vertebral levels, epidural and prevertebral, massive cement leaks were induced. Animals were evaluated daily. Two weeks later, the pigs were sacrificed, and the tissues that came in contact with the cement were analyzed. Results: The clinical results for each of the groups were reported. The control group had no clinical alterations. In the MTX group, 2 pigs died before 1 week due to pneumonitis. In the CYS group, 4 animals had motor impairment, and 3 of the 4 had paraplegia. The histological results were as follows: the control and MTX groups showed synovial metaplasia, inflammatory reaction, crystal deposits, and giant cell reaction in the dura mater and muscle and all the animals in the CYS group had spinal cord and muscular necrosis. Conclusions: Massive cement leak after vertebroplasty with PMMA loaded with cisplatin is extremely toxic to the spinal cord and muscles around the spine. Therefore, its use cannot be recommended for the treatment of vertebral metastases. Using PMMA loaded with methotrexate seems to be a safe procedure, but further research is needed.
Local and systemic diffusion of antineoplastic drugs following vertebroplasty using acrylic cement mixed with cisplatin or methotrexate: experimental study in pigs
(Springer, 2017) Llombart-Blanco, Rafael; Villas, Carlos; Silva, Álvaro; Aldaz, Azucena; Navarro, Iñigo; Forteza, Jeronimo; Matías Alfonso; Alfonso, Matías; Algarra, Salvador Martin
PURPOSE: To determine the efficacy of cisplatin- or methotrexate-containing acrylic cement for local and systemic antineoplastic drug diffusion. Among the uses of acrylic cement or Polymethylmethacrylate (PMMA), there is the possibility to employ it as vehicle for drug diffusion. This capability is of interest in the treatment of pathological fractures: The curative effects of the cement (cytotoxicity of the monomer and increased temperature) are added to the antineoplastic effect of the drugs. METHODS: In the experimental study, two groups of ten pigs underwent vertebroplasty using cement mixed with 500 mg of powder cisplatin or 1000 mg of powder methotrexate. Vertebroplasty was performed in two non-consecutive lumbar vertebrae with bipedicular cement injection. Transpedicular bone biopsy was performed weekly to measure levels of antineoplastic agent in bone tissue and blood plasma. Cisplatin was studied by atomic absorption spectrometry and methotrexate by fluorescence polarization immunoassay. Renal and hepatic function and blood analysis were performed weekly. RESULTS: Cisplatin and methotrexate levels were found in bone tissue at more than 5 weeks following surgery. The cisplatin peak occurred at week 3 (mean 1269 μg/g bone) and the methotrexate peak at week 1 (mean 862.76 μg/g bone). Plasma drug levels were found 72 h after surgery, with a peak at 24 h for cisplatin (mean 0.23 μmol/L) and at 30 min for methotrexate (mean 0.92 μmol/L). None of the animals died during the study. Animals with intracanal cement leaks showed no neurological involvement. Renal, hepatic and hemogram studies remained within normal limits. CONCLUSIONS: There is local diffusion of antineoplastic agents from the cement to bone and plasma. We found methotrexate and cisplatin levels in bone at up to 5 weeks, comparable to previous in vitro reports. At the doses administered, there were no cases of myelosuppression, hepatotoxicity, or nephrotoxicity.
Low Implant Failure Rate of Percutaneous Fixation for Spinal Metastases: A Multicenter Retrospective Study
(2021) Silva, Álvaro; Yurac, Ratko; Guiroy, Alfredo; Bravo, Oscar; Morales, Alejandro; Landriel, Federico; Hem, Santiago
OBJECTIVE: To evaluate incidence and types of implant failure observed in a series of patients with spinal metastases (SM) treated with minimally invasive stabilizationsurgery without fusion. METHODS: In this multicenter, retrospective, observational study, we reviewed the files of patients >18 years old who underwent surgery for SM using percutaneous spinal stabilization without fusion with a minimum 3-month followup. The following variables were included: demographics,clinical findings, prior radiation history, SM location, epidural spinal cord compression scale, Spinal Instability Neoplastic Scale, neurological examination, and surgeryrelated data. Primary outcome measure was implant failure rate, as observed in patients’ last computed tomography scan. Multivariable analysis was performed to identify baseline factors and factors associated with implant failure. RESULTS: Analysis included 72 patients. Mean age of patients was 62 years, 39 patients were men, and 75% of patients had an intermediate Spinal Instability Neoplastic Scale score. Tumor separation surgery was performed in 48.6% of patients. Short instrumentation was indicated in 54.2% of patients. Three patients (4.2%) experienced implant failure (2 screw loosening, 1 screw cut-out); none of them required revision surgery. In 73.6% of cases, survival was >6 months. No significant predictors of failure were identified in the multivariate analysis. CONCLUSIONS: A low implant failure rate was observed over the short and medium term, even when short instrumentations without fusion were performed. These findings suggest that minimally invasive stabilization surgery without fusion may be an effective and safe way to treat complicated SM.
Manejo actual de las metástasis vertebrales: un trabajo en equipo
(2021) Silva, Álvaro; Bravo, Oscar; Salas, Claudio; Yurac, Ratko; Valencia, Javiera; Goset, Karen; Harbst, Hans; Córdova, Andrés
La enfermedad metastásica vertebral es frecuente en los pacientes con cáncer avanzado, y conlleva a complicaciones inherentes a su progresión, como lo son la fractura patológica vertebral y la compresión neural metastásica. Se realizó una revisión de los aspectos terapéuticos actuales del manejo de la progresión y de las complicaciones de la enfermedad metastásica vertebral, enfatizando su enfrentamiento sistémico y personalizado. Nuestro objetivo principal es proporcionar información sobre el tratamiento actual de esta afección y la utilidad del manejo sistémico y multidisciplinario.
Pathological axis fracture secondary to a solitary bone plasmacytoma: Two cases and a literature review
(2021) Yurac, Ratko; Silva, Álvaro; Delgado, Matias; Nuñez, Marilaura; López, Juan; Marre, Bartolome
Background: Solitay bone plasmocytoma (SBP) account for just 5-10% of all plasma cell neoplasms. They are infrequent in the cervical spine, especially involving the C0-C2 segment. In this article we conducted a literature review and present the diagnosis, management and long term course of two patients with SBP of C2 causing cervical instability. Methods: We assessed the clinical records of two patients with SBP in C2 and cervical instability attributed to SP-B involving C2. Both patients presented with progressive, severe cervicalgia, and the "sensation" of skull instability. Magnetic resonance imaging revealed an extensive, infiltrative lesion involving C2 vertebral body and lateral masses, consistent with a plasmacytoma. Results: Both patients underwent emergency posterior surgical stabilization with craniocervical fixation; this was accompanied by a C2 transpedicular biopsy. Postoperatively, patients exhibited no focal neurological deficits and rapidly became pain free. They additional recieved 25 sessions of local conventional radiation therapy. Both patients are doing well as respective 2 and 7-year follow-up. Conclusion: Although rare, unstable SBP may present atypical cervical location that readily responds to surgical descompression/fusion and radiotherapy.
Preoperative and Postoperative Sagittal Alignment and Compensatory Mechanisms in Patients With Posttraumatic Thoracolumbar Deformities Who Undergo Corrective Surgeries
(2021) Bravo, Oscar; Valencia, Manuel; Izquierdo, Guillermo; Novoa, Felipe; Riera, José; Silva, Álvaro
Background: Secondary posttraumatic spinal kyphosis is a fixed deformity that has an asymptomatic presentation in most patients, but in some, persistent pain and disability can develop refractory to conservative treatment, which may result in the need for corrective surgery. Our aim was to analyze the modification of sagittal alignment and the variation in compensation mechanisms of spinal-pelvic segments before and after surgical correction in a group of patients with symptomatic posttraumatic kyphosis. Methods: A retrospective cohort study of 16 consecutive patients from the beginning of 2007 until the beginning of 2017 who underwent surgery due to thoracolumbar sagittal deformities was performed. Regional kyphosis (RK), thoracic kyphosis (TK), lumbar lordosis (LL), lower lumbar lordosis (LLL), lumbar lordosis under the deformity (LLUD), pelvic incidence (PI), pelvic tilt (PT), sagittal vertical axis (SVA), and PI-LL were measured in preoperative and postoperative lateral full spine x rays. Statistical analysis was performed with the nonparametric Wilcoxon test to compare preoperative and postoperative radiologic variables. Results: Sixteen patients were included with a median age of 47.5 years (32–62 years), the median time elapsed from the accident until corrective surgery was 7 months (2–33 months), the median follow-up time was 16.5 months (6–80 months), and the most used corrective strategy was pedicle subtraction osteotomy (11/16 patients). Statistically and radiologically significant improvements were observed in RK (33.58 versus 128, P , .001) and LLUD (68.58 versus 618, P ¼ .017), with a noticeable decrease in PI-LL (158 versus 9.58, P ¼ .233). There were no statistically significant results regarding TK, LL, LLL, PI, PT, or SVA. Conclusions: Osteotomies are an effective tool to correct angular deformities at a local level after spine trauma. Posttraumatic kyphosis results in the compensation of sagittal imbalance through modification of segmental alignment of the mobile spine under the e deformity.
Resection of a sacral chordoma aided by neuronavigation: A case report
(2021) Silva, Álvaro; Quinteros, Guisela; Calvo, Rafael; Yurac, Ratko; Marré, Bartolomé
Background Chordomas are rare malignant neoplasms that are resistant to chemotherapy and conventional radiation therapy. The main factor that determines whether a localized tumor recurs is en-bloc resection with tumor-free margins. Intraoperative navigation is useful in this scenario, allowing for preoperative planning of the osteotomy. Presentation of the case A 60-year-old patient, who had been previously operated on for prostate cancer, presented with back pain after a minor accident. He was examined, and a sacral tumor that had been classified as positive for chordoma via biopsy was found. A neuronavigation-aided en bloc resection was carried out, with both S2 nerves, both sacroiliac joints and the coccyx all preserved. Two years after the operation, the patient was asymptomatic, without tumor recurrence shown on MRI. Conclusion The use of intraoperative navigation is a useful tool for guiding osteotomies during bone tumor en-bloc resection.
Spondylolysis Repair Using a Minimally Invasive Modified Buck Technique with Neuronavigation and Neuromonitoring in High School and Professional Athletes: Technical Notes, Case Series, and Literature Review
(2021) Yurac, Ratko; Bravo, José; Silva, Álvaro; Marré, Bartolomé
Background: Spondylolysis is a defect in the pars interarticularis of the vertebra that occurs frequently in high-performance young athletes. Although nonsurgical management is the mainstay of treatment, surgery is an option for patients with persistent symptoms despite multiple cycles of nonsurgical treatment. Performing a minimally invasive technique reduces complications, postsurgery pain, and hospitalization time and leads to a quick recovery. The aim of this study was to report the clinical results of a series of 3 patients treated with a modification of the Buck technique with a minimally invasive approach. Methods: Three high-performance athletes between 17 and 18 years old who were managed nonsurgically for at least 6 months underwent a modified Buck technique repair with a minimally invasive approach using cannulated compression screws, with neuronavigation and neuromonitoring. Patients were followed at least 6 months with computed tomography scans to assess consolidation and fixation status. Following rehabilitation and in the absence of pain, all 3 athletes returned to their respective sports. No complications were reported. Results: All patients presented with bilateral spondylolysis, at L3 in 1 case and at L5 in 2 cases. Patients received conservative management for 12-36 months before surgery. After surgery, consolidation was obtained at 4 months in all patients, who returned to their sports activities in <6 months. Conclusions: The proposed technique shows the advantages of performing minimally invasive surgery in young high-performance athletes, ensuring consolidation and early return to sports activity without complications.
Treatment strategies for managing cervical spine injuries in rugby players
(2021) Yurac, Ratko; Zamorano, Juan José; Quinteros, Guisela; Izquierdo, Guillermo; Novoa, Felipe; Brañes, Rocío; Valencia, Manuel; Silva, Álvaro; Marré, Bartolomé
Background: Cervical spine fractures are potentially catastrophic injuries in rugby players. Here, we reviewed seven patients who sustained rugby-related cervical spine fractures. Notably, three of seven fractures were missed on initial X-rays, but were ultimately documented on CT studies obtained an average of 10 days later. Methods: Seven patients sustained cervical spine fracture attributed to rugby (2009–2016) and were followed an average of 52 posttrauma months. Most injuries occurred at the C6-C7 level, and six of seven patients required surgery. Further, only two of seven patients exhibited resultant neurological deficits (e.g., one myelopathy and one radiculopathy). Results: Although the rugby injury was sufficiently documented on initial X-rays in four patients, three initial X-rays missed fractures, which were documented on the CT studies obtained an average of 10 days later. Conclusion: Rugby-related cervical fractures must be considered where players continue to complain of pain following trauma. Notably, routine X-rays may miss fractures in 3 of 7 cases (43%), thus warranting supplemental CT examinations to definitively rule out fractures.

Browsing by Author "Silva, Álvaro"

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