Nuestros investigadores

Matías Alfonso Olmos-García

Líneas de investigación
proyectos Vertebroplastia con Antineoplásicos
Índice H
9, (Google Scholar, 09/12/2018)

Publicaciones científicas más recientes (desde 2010)

Autores: Casajus-Ortega, A. ; Llombart-Blanco, Rafael; et al.
ISSN 0936-8051  Vol. 139  Nº 12  2019  págs. 1681 - 1690
Introduction A multitude of procedures has been described in the literature for the treatment of lesser toe deformities and there is currently no general consensus on the optimal method of fixation. The aim of this study is to assess the clinical and radiological outcomes of an intramedullary nitinol implant for the correction of lesser toe deformities, and to determine if the distal interphalangeal (DIP) joint and metatarsophalangeal (MTP) joint are modified during patient follow-up after correction of the PIP joint. Materials and methods A prospective analysis of 36 patients with claw toe or hammertoe who were treated with an intramedullary nitinol implant. Clinical manifestations and angulation of the metatarsophalangeal, proximal and distal interphalangeal (MTP, PIP, DIP) joints were evaluated in radiographic studies preoperatively, at first medical revision post-surgery, and after a minimum of 1 year of follow-up. Complications such as non-union rate, implant rupture, and implant infection were also evaluated during follow-up. Results All patients were women with an average age of 65.5 (range 47-82) years. The average follow-up time was 2.4 (range 1-5.7) years. Fifty intramedullary nitinol implants were used. The MTP joint extension and PIP joint flexion decreased by 15.9 degrees (95% CI - 19.11 to - 12.63) and 49.4 degrees (95% CI - 55.29 to - 43.52), respectively, at the end of follow-up. Moreover, the DIP joint flexion increased progressively during follow-up (13.7 degrees pre-surgery versus 35.6 in last medical check-up, 95% CI 13.24-30.57). There were four (8%) asymptomatic implant ruptures. The rate of fusion was 98%. Conclusion The reduction of the PIP joint using an intramedullary nitinol implant is a good option in lesser toe deformities, with few complications and a high rate of arthrodesis. Moreover, the PIP joint reduction affects both the MTP and DIP joints.
Autores: Montiel, Veronica, (Autor de correspondencia); Alfonso, Matías; Villas, Carlos; et al.
ISSN 1268-7731  Vol. 25  Nº 2  2019  págs. 158 - 164
Background: Exostoses at the base of the distal phalanx of the great toe are usually asymptomatic. The literature has not generally considered them as the origin of a possible problem resulting from a pressure conflict between hallux and shoe (medial aspect) or second toe (lateral aspect) nor a potential complication of surgical correction of hallux valgus deformity. No studies, to our knowledge, have evaluated its possible correlation with other foot disorders. When one of these neglected exostoses became painful after surgical correction of hallux valgus, we decided to start a study to determine their possible origin, prevalence in daily practice and histo-pathological morphology. Methods: Two hundred and fifty-four feet of patients (average age 41.7. y.) were enrolled in the study from January 2007 to June 2009. Dorsoplantar weight-bearing radiographs were used to analyze the presence of exostoses and their correlation with the distal phalanx morphology, metatarsal formula (or transverse plane orientation of the metatarsal heads parabola) and hallux valgus angles. Patients were classified according to their age and main symptom for consultation. Four exostoses removed from cadaver feet were also analyzed microscopically. Results: Osseous excrescences arising on the medial or lateral aspect at the proximal part of the terminal phalanx of the hallux were observed in 132 feet (51.9%). Thirty-five feet out of these 132 (13.7%) had exostoses on both sides of the phalanx.A statistically significant positive correlation was found between the presence of a medial exostosis of the phalanx and the severity of HVA. Patients with higher IPH and asymmetry angles have a lower prevalence of medial exostoses (p. <. 0.05). Amongst the different morphologies of the second phalanx, exostoses were most likely found in the standard form. Conclusions: Prevalence of exostoses at the base of the distal phalanx is high (51.9% of the studied feet). Histological findings would suggest that these exostoses could be considered a mechanical reactive process, produced by a chronic irritation by shoes. We encourage surgeons to be aware of its potential clinical implications. Direct resection is very simple and the most appropriate treatment for symptomatic cases.
Autores: Ripalda, Purificación; et al.
ISSN 1749-799X  Vol. 13  2018  págs. 72
Background: TGF-beta has been described as a mediator of fibrosis and scarring. Several studies achieved reduction in experimental scarring through the inhibition of TGF-beta. Fibroblasts have been defined as the cell population originating fibrosis, blocking fibroblast invasion may impair epidural fibrosis appearance. For this purpose, biocompatible materials used as mechanical barriers and a TGF-beta inhibitor peptide were evaluated in the reduction of epidural fibrosis. Methods: A L6 laminectomy was performed in 40 New Zealand white rabbits. Divided into four groups, each rabbit was assigned to receive either collagen sponge scaffold (CS group), gelatin-based gel (GCP group), P144 (R) (iTGF beta group), or left untreated (control group). Four weeks after surgery, cell density, collagen content, and new bone formation of the scar area were determined by histomorphometry. Two experienced pathologists scored dura mater adhesion, scar density, and inflammatory infiltrate in a blinded manner. Results: In all groups, laminectomy site was filled with fibrous tissue and the dura mater presented adhesions. Only GCP group presented a significant reduction in collagen content and scar density. Conclusion: GCP treatment reduces epidural fibrosis although did not prevent dura mater adhesion completely.
Autores: González, María Soledad; Zandio, B. ; et al.
ISSN 1522-8517  Vol. 20  Nº Supl. 3  2018  págs. 216 - 217
Autores: Alfonso, Matías; Cruz-Morande, S.; et al.
ISSN 0341-2695  Vol. 41  Nº 11  2017  págs. 2281 - 2287
Purpose Proximal medial gastrocnemius recession (PMGR) is a surgical procedure performed in patients with gastrocnemius tightness (GT). The purpose of this study is to evaluate the efficacy of pedobarographic analysis on PMGR in patients with GT and metatarsalgia. Methods This prospective study included 52 patients diagnosed with GT treated surgically with PMGR and 49 non-operated upon patients (control group). A total of 55 PMGRs (three bilateral) were performed as an isolated or combined procedure in the treatment group. Passive ankle dorsiflexion with knee flexion and extension was evaluated in all patients. In addition, pedobarographic analysis was performed before and after surgery. Results Median preoperative ankle dorsiflexion was -10.0 degrees (equinus) with extended knee and 10.0 degrees with flexed knee and postoperative differences in median ankle dorsiflexion was 12.5 degrees (extended knee) (p = 0.000) and 5.0 degrees (flexed knee) (p = 0.002). After the PMGR, the median area of the contact surface (-3.0 cm(2)) (p = 0.009), the maximum (-13,239.0 Pa) (p = 0.019) and mean pressure (-2,942.0 Pa) and the forefoot force (-70.0 N) (p = 0.000) decreased. An increase in hindfoot force (20.0 N), hindfoot bearing time (4.0 ms) (p = 0.005), and forefoot bearing time (1.0 ms) was also observed. Conclusions Pedobarographic analysis is an efficient tool to evaluate surgical procedures that assess metatarsal overload. PMGR is an effective surgical procedure to improve passive ankle range of motion and decrease forefoot plantar overload.
Autores: Llombart-Blanco, Rafael; Villas, Carlos; Silva, Á.; et al.
ISSN 0940-6719  Vol. 26  Nº 12  2017  págs. 3216 - 3224
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 ¿g/g bone) and the methotrexate peak at week 1 (mean 862.76 ¿g/g bone). Plasma drug levels were found 72 h after surgery, with a peak at 24 h for cisplatin (mean 0.23 ¿mol/L) and at 30 min for methotrexate (mean 0.92 ¿mol/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.
Autores: Villas, Carlos; et al.
ISSN 1067-2516  Vol. 55  Nº 3  2016  págs. 461-4
We used coronal computed tomography to determine the normal sesamoid position in 20 healthy volunteers. The sample involved 40 feet (20 left [50%] and 20 right [50%]) in 20 volunteers, including 11 females (55%) and 9 males (45%). The relationship between the first metatarsal head and the sesamoid complex was categorized as Yildirim grade 0 in every case (100%). The mean width of the foot was 77.7 ± 5.8 mm, and the ratio of the foot width to the distance from the second metatarsal head to the tibial sesamoid was 39.6% ± 2.02%. Based on our findings, we consider Yildirim grade 0 to be the normal sesamoid alignment.
Autores: Villas, Carlos; et al.
ISSN 1067-2516  Vol. 54  Nº 6  2015  págs. 1111-1115
Some investigators have emphasized restoring the relationship between the sesamoid complex and the first metatarsal head to reduce the risk of hallux valgus recurring after surgical reconstruction. In a prospective study, we analyzed whether the first metatarsophalangeal joint could be realigned after scarf-Akin bunionectomy without lateral soft tissue release. A total of 25 feet, in 22 patients, were prospectively enrolled and analyzed using anteroposterior radiographs and coronal computed tomography scans obtained before and 3 months after surgery. The Yildirim sesamoid position decreased from a preoperative of 2 (range 1 to 3) to a postoperative position of 0 (range 0 to 1; p < .001), the mean first intermetatarsal angle decreased from 12.6° ± 2.4° to 5.8° ± 2.1° (p < .001), and the mean distance between the second metatarsal and the tibial sesamoid changed from 25.7 ± 4.6 to 25.9 ± 4.6 (p = .59). Our findings suggest that dislocation of the sesamoid complex is actually caused by displacement of the first metatarsal. In conclusion, the scarf-Akin bunionectomy adequately restores the alignment of the first metatarsophalangeal joint, including restoration of the sesamoid apparatus, without direct plantar-lateral soft tissue release
Autores: Alfonso, Matías; Villas, Carlos;
ISSN 1137-6627  Vol. 38  Nº 3  2015  págs. 417-424
Los resultados obtenidos sugieren que tras la aplicación del protocolo de atenuación del artefacto en equipo de TCMC de 64 coronas el artefacto es reducido a unas dimensiones similares a la dimensión real del tornillo pedicular.
Autores: Llombart-Blanco, Rafael; Alfonso, Matías; Villas, Carlos; et al.
ISSN 0940-6719  Vol. 23  Nº 1  2014  págs. 276 - 277
Autores: Alfonso, Matías; Villas, Carlos; et al.
ISSN 1976-1902  Vol. 7  Nº 3  2013  págs. 159-166
The spinal cord was normal; it is likely that dura mater and cerebrospinal fluid are responsible to isolate neural structures from cement. Dura mater and muscle showed similar histological changes than other publications. Synovial metaplasia was observed in dura mater and muscles that came into contact with cement. The pulsatile rubbing between the tissue and cement could be responsible of this phenomenon.
Autores: Alfonso, Matías; Villas, Carlos; et al.
ISSN 2035-5106  Vol. 97  Nº 2  2013  págs. 159 - 164
Artifact may lead to confusion when evaluating postoperative CT scans of lumbar pedicle screws. The aim of our study was to develop a specific metal artifact reduction image protocol, in order to reduce metal artifact caused by titanium pedicular screw in patients undergoing lumbar pathology by lumbar fusion. Therefore, the reduction in metal artifacts in lumbar pedicle screws allows surgeons to do an accurate diagnosis of the exact placement of inserted pedicle screws, minimizes false reexploration, and maximizes proper and prompt treatment of misplaced screw. In a first step, we performed a retrospective study of 103 titanium alloy pedicle screws in patients undergoing a lumbar instrumented fusion for treatment for degenerative disease. CT scan was performed postoperatively evaluating the possible overdimension caused by artifact. In a second step, a prospective study was performed using a 64-slice multidetector-row computed tomography (MDCT) in 104 titanium alloy pedicle screws in patients undergoing a lumbar instrumented fusion for treatment for degenerative disease. Our results show that on the group of sequential CT scan, mean overdimension (on each side) due to brightness was 1.045 mm (SD 0.45). On the group of 64-slice multichannel CT, mean overdimension (on each side) due to brightness was 0.005 mm at the proximal part of the screw and 0.025 mm at the distal part of the screw. The results observed suggest that beam-hardening artifacts caused by the screw on CT after
Autores: Yuste, JR; Alfonso, Matías; Bustos, César Egberto; et al.
ISSN 0300-8126  Vol. 40  Nº 4  2012  págs. 445 - 449
Candida osteomyelitis is a well recognized but infrequent entity. We describe an interesting case of iliac bone C. albicans osteomyelitis as a result of a surgical trauma of an iliac bone for the auto-grafting of a fracture in the lumbar spine. The peri-operative acquisition of Candida was by the inoculation of a yeast colonizing the skin. Remarkably, several risk factors described for Candida infection and candidemia were absent. The patient also presented with a local fistula. The iliac crest was the only bone affected and local pain was the only symptom present in our case. Diagnosis was made by multiple-specimen biopsy obtained by surgery. Treatment with fluconazole was successful.
Autores: Alfonso, Matías; Aldaz, Azucena; et al.
Revista: European Spine Journal
ISSN 0940-6719  Vol. 20  Nº 2  2011  págs. 338 - 339
Study Design: Prospective, experimental study in animals, approved by the local ethics committee for animal research. Aims: To evaluate and compare the histological changes in myeloradicular structures and paravertebral tissue induced by contact with acrylic cement with and without methotrexate in vertebroplasty in pigs. Material and Methods: Ten female pigs of the Large White¿Landrace breed, weighing 30 kg and divided into two groups: control group, containing five pigs that underwent vertebroplasty with acrylic cement, and methotrexate group, with five pigs that underwent vertebroplasty using cement combined with 1 g of methotrexate. A standard fluoroscopy-guide transpedicular vertebroplasty technique was performed with an 11-G trocar. Cement leak to the prevertebral and epidural muscle tissue was induced in two different lumbar vertebrae; 1 cc of cement was injected per vertebra. Animals were sacrificed at 3 weeks. Spines were removed, the section where tissues were in contact with cement was isolated by dissection, the surface in direct contact with cement was marked with India ink, and specimens were processed by fixation and hematoxylin eosin staining for pos-terior microscopic study. Results: Macroscopic results: In both groups, the cement was distributed in layers surrounding the dural sac. Histological results: In the control group, leakage to the prevertebral musculature with atrophy of muscle fibers, inflammatory infiltrate in areas in contact with cement, epithelial dysplasia, and foreign body reaction in relation to cement particles. In addition, epidural leak with dural thickening and inflammatory reaction only in areas of the dura mater in contact with cement. In the methotrexate group, the same changes as in the control group were observed. Clinical results: Neurological lesion due to cement leak was not produced any of the ten pigs. Conclusions:The tube-like laminar distribution of the cement may explain the fact that there was an absence of paraplegia in the study animals. Contact of the muscle and dura with cement seemed to induce an inflammatory reaction, with cell death, and atrophy and thickening of membranes in some cases. Addition of methotrexate to acrylic cement did not seem to increase the local toxicity of cement alone.
Autores: Alfonso, Matías; et al.
Revista: Revista española de cirugía ortopédica y traumatología (Ed. impresa)
ISSN 1888-4415  Vol. 55 Esp. Congreso  Nº CC-669  2011  págs. 346 - 347
Autores: Llombart-Blanco, Rafael; et al.
Revista: Revista española de cirugía ortopédica y traumatología (Ed. impresa)
ISSN 1888-4415  Vol. 55 Espec. Congreso  Nº CC-81  2011  págs. 147
Introducción y objetivos: Los osteocondromas afectan raramente a la columna cervical y la literatura refiere normalmente casos por compresión medular. El diagnóstico es difícil ya que rara vez se sospecha. El caso que presentamos plantea cuestiones en cuanto al diagnóstico, la indicación y el abordaje quirúrgico así como la necesidad de añadir o no una artrodesis. Material y método: Mujer de 26 años, con dolor occipital/suboccipital izquierdo desde hacía 17 años. Diagnosticada previamente de osteocondroma en arco posterior de C2, se aconsejó esperar y ver por dificultad y riesgo en caso de intervención. El dolor era constante y referido al ¿Punto de Arnold¿ con irradiación a occipital, y aumentaba con los movimientos del cuello. Las radiografías simples no fueron orientativas. En TC se observó una lesión compatible con osteoma osteoide del arco posterior del atlas (en axial) una prominencia ósea que nacía del istmo del axis (cortes coronales y sagitales). Era compatible con un osteocondroma de crecimiento vertical. Los cortes sagitales y coronales mostraban una anquilosis inter-apofisaria de articulación C1C2 izquierda. La gammagrafía mostraba hipercaptación en dicha articulación, sin hipercaptación en la lesión. La intervención quirúrgica (abordaje posterior medio) consistió en resección simple de la lesión mediante osteotomía de su base, siendo fácilmente separable del arco posterior de C1. La raíz C2 izquierda estaba ¿anclada¿ por el osteocondroma en su división, siendo difícil movilizar su ramo posterior. Resultados: El dolor cedió inmediatamente permaneciendo la paciente asintomática durante todo su seguimiento. La anatomía patológica confirmó el diagnóstico de osteocondroma. Comentarios y conclusiones: El dolor en el ¿Punto de Arnold¿ área occipital puede ser debido a causas diversas, incluyendo degeneración en C1C2. En este caso, el osteocondroma creció provocando a la paciente dolor durante 17 años y la degeneración observada en la articulación inter-apofisaria adyacente ipsilateral pudo ser reactiva, como en el caso de algunos fenómenos observados en el raquis cervical en torno al osteoma osteoide. Las dudas que planteaba la posible anquilosis C1C2 podrían crear controversia acerca de la indicación de añadir o no artrodesis C1C2 Una vez fue desestimada la fusión C1C2, podría tenerse en cuenta un abordaje posterolateral directo como opción.
Autores: Villas, Carlos; Alfonso, Matías; et al.
Revista: European Spine Journal
ISSN 0940-6719  Vol. 20  2011  págs. 310 - 340
Autores: Villas, Carlos; Alfonso, Matías;
Revista: European Spine Journal
ISSN 0940-6719  Vol. 20  Nº 11  2011  págs. 2067- 2095
Autores: Alfonso, Matías; et al.
Revista: European Spine Journal
ISSN 0940-6719  Vol. 20  Nº 2  2011  págs. 314 - 340
Autores: Alfonso, Matías; Yuste, JR; et al.
Revista: Revista española de cirugía ortopédica y traumatología (Ed. impresa)
ISSN 1888-4415  Vol. 55 Esp. Congreso  Nº CC-921  2011  págs. 431 - 432
Autores: Villas, Carlos; Alfonso, Matías; Hidalgo Espinola, Martín; et al.
Revista: European Spine Journal
ISSN 0940-6719  Vol. 20  Nº 2  2011  págs. 338
Autores: Alfonso, Matías; Llombart-Blanco, Rafael; et al.
Revista: European Spine Journal
ISSN 0940-6719  Vol. 20  Nº 11  2011  págs. 2094 - 2095
To evaluate and compare the histological changes in spinal cord and nerve root structures and perivertebral tissues induced by contact with acrylic bone cement containing cisplatin, injected by vertebroplasty in pigs.
Autores: Alfonso, Matías; Villas, Carlos; et al.
Revista: European Spine Journal
ISSN 0940-6719  Vol. 19  Nº 1  2010  págs. 179
Autores: Villas, Carlos; Alfonso, Matías; et al.
Revista: European Spine Journal
ISSN 0940-6719  Vol. 19  Nº 6  2010  págs. 1061 -
Autores: Alfonso, Matías; et al.
ISSN 1389-9333  Vol. 11  Nº 3  2010  págs. 295-298
Infection is one of the most dangerous complications that can be seen when implanting bone or tendon allografts from a deceased donor. The most common germs isolated are found among the cutaneous florae, but sometimes they may be present in the bloodstream as a result of severe injuries suffered before the time of the decease. We present a case of contamination of allografts in a musculoskeletal tissue donor deceased after an accident, whose allografts were contaminated by gastrointestinal microorganisms, probably disseminated through the donor's blood
Autores: Alfonso, Matías; Villas, Carlos; et al.
Revista: European Spine Journal
ISSN 0940-6719  Vol. 19  Nº 1  2010  págs. 157
Autores: Alfonso, Matías; Villas, Carlos; et al.
Revista: European Spine Journal
ISSN 0940-6719  Vol. 19  Nº 1  2010  págs. 177
Aim: To determine the reliability of cytology during vertebroplasty for the diagnosis of neoplastic disease. Material and Methods: Review of patients who underwent vertebroplasty (for osteoporotic or tumor fractures), in whom samples were obtained by cytology and/or biopsy. The results were compared with the radiologic diagnosis. Results: Cytology and/or biopsy were performed in 63 patients (102 vertebrae) during vertebroplasty surgery. In 41, only cytology was done, in 16 only biopsy, and in six biopsy and cytology. In six patients, a discordant diagnosis was obtained between MR study, which indicated tumor involvement and the histological diagnosis, which indicated that there was no tumor. Five of these six patients only had a cytology study (reported as hemorrhagic or without tumor cells) and one patient had cytology and biopsy, in which the cytology was negative and the biopsy positive. Cytology did not test positive for tumor cells in any patient in whom tumor was not suspected on imaging and in six cases (9.5%), cytology failed to detect disease: two myelomas, one breast cancer metastasis, and three lung cancer metastasis. There were no erroneous diagnoses in any patient who underwent bone biopsy (2 with insufficient material). Conclusion: As a diagnostic technique during vertebroplasty, cytology presented a false-negative rate that could be improved with trocar bone biopsy. Cytology should be used when it is impossible to remove a specimen of vertebral bone.
Autores: Alfonso, Matías; del Pozo, José Luis;
Libro:  Patología de la columna vertebral
2015  págs. 525 - 535
Autores: Villas, Carlos; Alfonso, Matías;
Libro:  Patología de la columna vertebral
Vol.   Nº 35  2015  págs. 493-511
Autores: Villas, Carlos; Alfonso, Matías; riera; et al.
Libro:  Cirugía de la columna cervical
2015  págs. 53 - 69
Autores: Llombart Blanco, R.; González Gil, A.B.; Gallego Bustos, J.M.; et al.
Libro:  Libro de casos clínicos en ortopedia y traumatología
Nº 4  2012  págs. 147-150
Autores: Lamo de Espinosa Vázquez de Sola, J.M.; González Gil, A.B.; Sanz Esquiroz, I.; et al.
Libro:  Libro de casos clínicos de residentes en cirugía ortopédica y traumatología 2011
Nº 11  2011  págs. 121-123
Autores: Crespo Cullell, I.; Lamo de Espinosa Vázquez de Sola, J. M.a; Cruz Morandé, S.; et al.
Libro:  Libro de casos clínicos de residentes en cirugía ortopédica y traumatología 2011
Nº 11  2011  págs. 88-90