Induction of a NOTCH3 Lehman syndrome mutation in osteocytes causes osteopenia in male C57BL/6J mice.

Lateral Meningocele or Lehman Syndrome (LMS) is associated with NOTCH3 mutations causing deletions of the PEST domain and a gain-of-NOTCH3 function. We demonstrated that Notch3em1Ecan mice harboring Notch3 mutations analogous to those found in LMS are osteopenic because of enhanced bone resorption. To determine the contribution of specific cell lineages to the phenotype, we created a conditional-by-inversion (Notch3COIN) model termed Notch3em2Ecan in which Cre recombination generates a Notch3INV allele expressing a NOTCH3 mutant lacking the PEST domain. Germ line Notch3COIN inversion caused osteopenia and phenocopied the Notch3em1Ecan mutant, validating the model. To induce the mutation in osteocytes, smooth muscle and endothelial cells, Notch3COIN mice were bred with mice expressing Cre from the Dmp1, Sm22a and Cdh5 promoters, respectively, creating experimental mice harboring Notch3INV alleles in Cre-expressing cells and control littermates harboring Notch3COIN alleles. Notch3COIN inversion in osteocytes led to femoral and vertebral cancellous bone osteopenia, whereas Notch3COIN inversion in mural Sm22a or endothelial Cdh5-expressing cells did not result in a skeletal phenotype. In conclusion, introduction of the LMS mutation in osteocytes but not in vascular cells causes osteopenia and phenocopies Notch3em1Ecan global mutant mice.

Role of nuclear factor of activated T cells in chondrogenesis osteogenesis and osteochondroma formation.

PURPOSE: Nuclear factor of activated T cells (NFATc) are transcription factors that play a function in the immune response and in osteoclast differentiation. In the present work, we define the function of NFATc2 in chondrogenic and osteogenic cells. METHODS: Nfatc2loxP/loxP and Nfatc1loxP/loxP;Nfatc2loxP/loxP conditional mice were crossed with Prx1-Cre transgenics to inactivate Nfatc2 singly and with Nfatc1. Femurs and vertebrae were examined by microcomputed tomography (µCT) X-Ray images and histology and analyzed for the presence of osteochondromas. RESULTS: µCT demonstrated that Prx1-Cre;Nfatc2∆/∆ female mice had transient osteopenia and male mice did not have a cancellous or a cortical bone phenotype when compared to control mice. In contrast, the dual inactivation of Nfatc1 and Nfatc2 in Prx1-expressing cells resulted in cancellous osteopenia and small bones at 1 month of age in both sexes. Nfatc1;Nfatc2 deleted mice exhibited a ~ 50% decrease in bone volume and connectivity. Total bone area, periosteal and endocortical bone perimeters and femoral length were reduced indicating smaller bones. As the mice matured, the shortening of the femoral length persisted, but the osteopenic phenotype resolved and cancellous femoral bone of 4-month-old Nfatc1;Nfatc2 deleted mice was not different from controls although male mice had vertebral osteopenia. In addition, Nfatc1;Nfatc2 deleted mice displayed distortion of the distal metaphysis and, as they matured, the articular presence of mineralized tumors with the appearance of osteochondromas. CONCLUSION: Our studies reveal that NFATc1 and NFATc2 are necessary for optimal bone homeostasis and the suppression of osteochondroma formation.

Correction to: Notch in skeletal physiology and disease.

Table 2 of the original article was incorrect. The correct table is shown below.

Clinico-pathological features of the intradiaphragmatic bronchogenic cysts: report of a case and review of the literature.

Bronchogenic cysts represent congenital malformations deriving from an abnormal development of the primitive foregut during embryogenesis. These lesions are rarely found and they are most frequently localized in the mediastinum, or in lung parenchyma. Intramuscular localization is extremely rare, especially within the diaphragm. We report a case of a 54 year old man showing a large lobulated cystic lesion in the left hemidiaphragm. Complete surgery was performed and histological diagnosis of intradiaphragmatic bronchogenic cyst was made during surgery and confirmed after a total section analysis. Moreover we reviewed the other cases published in the English literature, including clinical, surgical and pathological data.

Notch in skeletal physiology and disease.

Notch (Notch1 through 4) are transmembrane receptors that play a fundamental role in cell differentiation and function. Notch receptors are activated following interactions with their ligands in neighboring cells. There are five classic ligands termed Jagged (Jag)1 and Jag2 and Delta-like (Dll)1, Dll3, and Dll4. Recent work has established Notch as a signaling pathway that plays a critical role in the differentiation and function of cells of the osteoblast and osteoclast lineages and in skeletal development and bone remodeling. The effects of Notch are cell-context dependent, and the four Notch receptors carry out specific functions in the skeleton. Gain- and loss-of-function mutations of components of the Notch signaling pathway result in a variety of congenital disorders with significant craniofacial and skeletal manifestations. The Notch ligand Jag1 is a determinant of bone mineral density, and Notch plays a role in the early phases of fracture healing. Alterations in Notch signaling are associated with osteosarcoma and with the metastatic potential of carcinoma of the breast and of the prostate. Controlling Notch signaling could prove useful in diseases of Notch gain-of-function and in selected skeletal disorders. However, clinical data on agents that modify Notch signaling are not available. In conclusion, Notch signaling is a novel pathway that regulates skeletal homeostasis in health and disease.

Mice harboring a Hajdu Cheney Syndrome mutation are sensitized to osteoarthritis.

Osteoarthritis is a joint disease characterized by cartilage degradation, altered gene expression and inflammation. NOTCH1 and NOTCH2 receptors and the JAGGED1 ligand regulate chondrocyte biology; however, the contribution of Notch signaling to osteoarthritis is controversial. Hajdu Cheney Syndrome (HCS) is a rare genetic disorder affecting the skeleton and associated with NOTCH2 mutations that lead to NOTCH2 gain-of-function. A murine model of the disease (Notch2tm1.1Ecan) was used to test whether the HCS mutation increases the susceptibility to osteoarthritis. The knee of three-month-old Notch2tm1.1Ecan male mice and control sex-matched littermates was destabilized by resection of the medial meniscotibial ligament, and changes in the joint analyzed two months thereafter. Expression of Notch target genes was increased in the femoral heads of Notch2tm1.1Ecan mice, documenting Notch signal activation. Periarticular bone and cartilage structures were unaffected in Notch2tm1.1Ecan mutants subjected to sham surgery, indicating that NOTCH2 gain-of-function had no discernible impact on joint structure under basal conditions. However, destabilization of the medial meniscus increased osteophyte volume and thickened subchondral bone in Notch2tm1.1Ecan mice compared to wild type littermates. Moreover, destabilized Notch2tm1.1Ecan mutants exhibited histological signs of moderate to severe cartilage degeneration, demonstrating joint sensitization to the development of osteoarthritis. Chondrocyte cultures from Notch2tm1.1Ecan mutants expressed increased Il6 mRNA levels following exposure to JAGGED1, possibly explaining the susceptibility of Notch2tm1.1Ecan mice to osteoarthritis. In conclusion, Notch2tm1.1Ecan mutants are sensitized to the development of osteoarthritis in destabilized joints and NOTCH2 activation may play a role in the pathogenesis of the disease.

Interleukin 6 mediates selected effects of Notch in chondrocytes.

OBJECTIVE: Notch receptors determine cell fate by regulating transcription, an event mediated by the Notch intracellular domain (NICD), which is generated by proteolysis brought about by Notch-ligand interactions. Since Notch activation or exposure to interleukin (Il)6 have similar effects in chondrocytes, we explored whether interleukin 6 (Il6) contributes to the mechanisms of Notch action in these cells. METHOD: NICD was overexpressed in primary chondrocytes from Rosa(Notch) mice, where the Rosa26 promoter precedes a loxP-flanked STOP cassette followed by the NICD coding sequence. Cells were infected with adenoviral vectors expressing Cre to induce NICD or green fluorescent protein (GFP) as control. Gene expression was determined by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Il6 protein concentration in the culture media was determined by enzyme-linked immunosorbent assay (ELISA). To test the mechanisms of Notch action on Il6 expression, cells were transfected with a fragment of the Il6 promoter or control vector pGL3, or transcriptionally arrested with 5,6-dichloro-1-ß-d-ribofuranosylbenzimidazole. Il6 was inhibited with a neutralizing antibody, whereas a normal immunoglobulin G (IgG) was used as control. RESULTS: NICD induced Il6 mRNA and protein, and transactivated the Il6 promoter without affecting Il6 mRNA stability. Il6 neutralization had no impact on gene expression under basal conditions, and did not modify the effects of NICD on sex determining region-Y-related high mobility group-box gene (Sox)9, collagen type II α1 (Col2a1) and collagen type X α1 (Col10a1) expression. Conversely, Il6 neutralization opposed aggrecan (Acan) suppression and prevented matrix metalloprotease (Mmp)13 induction by NICD. CONCLUSION: Il6 mediates suppression of Acan and induction of Mmp13 expression by Notch in chondrocytes.

Tumores malignos de la pared torácica / No disponible

Los tumores de la pared torácica son poco frecuentes. Con la finalidad de revisar los resultados obtenidos en el tratamiento, se presentan los casos tratados quirúrgicamente entre 1992 y 2009. La serie viene constituida por 35 pacientes (23 varones), con una edad media de 55 años (rangos 21-82). La presentación fue con síntomas de duración media de 8,9 meses en 30 casos. El diagnóstico se basó en los medios de imagen (radiografía simple 100%, tomografía computarizada 85,7%, gammagrafía ósea 20,1%, ecografía 17,1%, resonancia magnética 14,3%) y la biopsia de la masa (punción transtorácica 37,1%, biopsia incisional en el 5,7% y en el 62,9% biopsia escisional previa a lacirugía completa). El tratamiento quirúrgico fue la escisión completa con márgenes libres de 3-5 cm, cuando ello fue posible y la ulterior reconstrucción con mallas de pared y mioplastias. Se realizó un análisis de la supervivencia, valorándola en función de parámetros como la edad, sexo, tamaño del tumor y grado de malignidad del tumor. En 2 casos (5,7%) se quedaron márgenes afectos. Recibieron tratamiento adyuvante 11 pacientes (5 quimioterapia y 6 radioterapia). Se produjeron complicaciones postoperatorias en 6 casos (17,3%) y no hubo mortalidad postoperatoria. En cuanto al seguimiento, hubo recidiva locorregional en 6 casos (17,3%) y metástasis en 7 (20%). La supervivencia no se relacionó estadísticamente con el grado de malignidad del tumor. Se concluye que la cirugía de resección de los tumores primarios malignos de la pared torácica no tiene mortalidad en nuestra experiencia. Tiene una escasa morbilidad postoperatoria. Tienen una supervivencia no relacionada con el grado de malignidad de la neoplasia, siempre que se obtengan unos márgenes quirúrgicos correctos (AU)

tumors, we present our cases surgically treated between 1992 and 2009. The series is formed by 35 cases (23 males), with a mean age of 55 (ranges 21-82). The presentation was with symptoms of 8,9 month of average duration in 30 cases. Diagnosis was based in imaging test (chest radiography 100%, computed tomography 85,7%, bone scintigraphy 20,1%, ultrasonography 17,1%, magnetic resonance 14,3%) and tumor biopsy (transthoracic punction 37,1%, incisional biopsy 5,7% and excisional biopsy in 62,9% previous to complete surgical resection). Surgical reatment was complete excision with margin free tumor of 3-5 cm when it was possible and chest wall reconstruction with mesh and myoplastia. Survival analysis was made evaluating age, sex, tumor size and grade. There were affected margins in 2 cases (5,7%). Adjuvant treatment was used in 11 patients (5 chemotherapy, 6 radiotherapy). Postoperative complications were present in 6 cases (17,3%). There was not mortality. Local relapses were present in 6 patients (17,3%) and metastases in 7 (20%). Survival was not related with the tumor grade. We conclude that surgical treatment of malignant chest wall tumors has not mortality in our experience. Postoperative morbidity is low. Survival is not related to tumor grade if enough free tumor margins is obtained (AU)

New understanding and treatments for osteoporosis.

To summarize promising areas of investigation in osteoporosis and to stimulate further research in this area, as discussed in a recent international conference. Over the recent years, there has been an improvement in the knowledge of molecular pathways involved in bone formation and resorption with the development of new drugs to treat osteoporosis. Intact parathyroid hormone, teriparatide, and anti-sclerostin monoclonal antibody are anabolic drugs, whereas denosumab and odanacatib are anti-resorptive drugs with more reversible effects as compared to bisphosphonates. Anabolic and anti-resorptive agents have different effects on bone, and research in this area includes the efficacy of combination and sequential therapies with them. New insights in the molecular pathways of bone remodeling have clarified the mechanisms responsible for skeletal fragility in several forms of secondary osteoporosis, such as that occurring in type 2 diabetes, following drug exposure and systemic inflammatory diseases. Future research is needed to address the efficacy of anti-osteoporotic drugs in these more recently recognized conditions of skeletal fragility. Osteoporosis continues to be an important field of biomedical research.

Glucocorticoid-induced osteoporosis and parathyroid hormone.

Glucocorticoid-induced osteoporosis (GIO) is the most common form of secondary osteoporosis. Bisphosphonates are considered the first-line treatment option for the majority of glucocorticoid-treated patients at increased risk of fractures. However, the anti-resorptive mechanism of bisphosphonates does not address the major pathophysiological mechanisms of impaired bone formation during chronic glucocorticoid treatment. PTH, when administered intermittently and at low doses, has effects on bone formation opposite to those of glucocorticoids and therefore is conceptually a more attractive approach. Teriparatide (1-34PTH) has been studied in patients with GIO with effects on bone mineral density and on fracture risk which were shown to be superior to those obtained with alendronate.

Prevention and treatment of glucocorticoid-induced osteoporosis.

Glucocorticoid-induced osteoporosis (GIO) is the most common form of secondary osteoporosis with fractures occurring in as many as 30-50% of patients receiving chronic glucocorticoid therapy. Calcium and vitamin D are important measures in the primary prevention of GIO. However, vitamin D and calcium alone do not allow to prevent fractures. Estrogens and androgens should be used in patients with documented hypogonadism. Bisphosphonates are the most effective of the various therapies that have been assessed for the management of GIO. These drugs need to be started early in order to correct the increase in bone resorption occurring in the first weeks of glucocorticoid treatment. Anabolic therapeutic strategies are under investigation. Teriparatide seems to be also efficacious for the treatment of patients with GIO.

Gender-specific changes in bone turnover and skeletal architecture in igfbp-2-null mice.

IGF-binding protein-2 (IGFBP-2) is a 36-kDa protein that binds to the IGFs with high affinity. To determine its role in bone turnover, we compared Igfbp2(-/-) mice with Igfbp2(+/+) colony controls. Igfbp2(-/-) males had shorter femurs and were heavier than controls but were not insulin resistant. Serum IGF-I levels in Igfbp2(-/-) mice were 10% higher than Igfbp2(+/+) controls at 8 wk of age; in males, this was accompanied by a 3-fold increase in hepatic Igfbp3 and Igfbp5 mRNA transcripts compared with Igfbp2(+/+) controls. The skeletal phenotype of the Igfbp2(-/-) mice was gender and compartment specific; Igfbp2(-/-) females had increased cortical thickness with a greater periosteal circumference compared with controls, whereas male Igfbp2(-/-) males had reduced cortical bone area and a 20% reduction in the trabecular bone volume fraction due to thinner trabeculae than Igfbp2(+/+) controls. Serum osteocalcin levels were reduced by nearly 40% in Igfbp2(-/-) males, and in vitro, both CFU-ALP(+) preosteoblasts, and tartrate-resistant acid phosphatase-positive osteoclasts were significantly less abundant than in Igfbp2(+/+) male mice. Histomorphometry confirmed fewer osteoblasts and osteoclasts per bone perimeter and reduced bone formation in the Igfbp2(-/-) males. Lysates from both osteoblasts and osteoclasts in the Igfbp2(-/-) males had phosphatase and tensin homolog (PTEN) levels that were significantly higher than Igfbp2(+/+) controls and were suppressed by addition of exogenous IGFBP-2. In summary, there are gender- and compartment-specific changes in Igfbp2(-/-) mice. IGFBP-2 may regulate bone turnover in both an IGF-I-dependent and -independent manner.

Glucocorticoid-induced osteoporosis: pathophysiology and therapy.

Glucocorticoid-induced osteoporosis (GIO) is the most common form of secondary osteoporosis. Fractures, which are often asymptomatic, may occur in as many as 30-50% of patients receiving chronic glucocorticoid therapy. Vertebral fractures occur early after exposure to glucocorticoids, at a time when bone mineral density (BMD) declines rapidly. Fractures tend to occur at higher BMD levels than in women with postmenopausal osteoporosis. In human subjects, the early rapid decline in BMD is followed by a slower progressive decline in BMD. Glucocorticoids have direct and indirect effects on the skeleton. The primary effects are on osteoblasts and osteocytes. Glucocorticoids impair the replication, differentiation and function of osteoblasts and induce the apoptosis of mature osteoblasts and osteocytes. These effects lead to a suppression of bone formation, a central feature in the pathogenesis of GIO. Glucocorticoids also favor osteoclastogenesis and as a consequence increase bone resorption. Bisphosphonates are effective in the prevention and treatment of GIO. Anabolic therapeutic strategies are under investigation.

Signals that determine the fate of osteoblastic cells.

Signals that determine skeletal cell fate, function and apoptosis are critical to normal bone remodeling. Skeletal cells synthesize growth factors; some regulate cell replication, others regulate osteoblastic differentiation. Bone morphogenetic proteins (BMP) and Wnts induce the differentiation of mesenchymal cells toward mature osteoblasts. The action of BMPs is regulated by extracellular antagonists. These often act by binding to BMPs and preventing their binding to cell surface receptors. Wnt is essential for osteoblastogenesis, and mutations of Wnt co-receptors are associated with changes in bone mass. Wnt activity, like BMPs, is regulated by extracellular and intracellular antagonists. Notch, a family of transmembrane receptors, opposes Wnt signaling and inhibits osteoblastic differentiation. BMP, Wnt and Notch play a central role in osteoblastic cell fate.

Overexpression of IGF-binding protein 5 alters mineral and matrix properties in mouse femora: an infrared imaging study.

The anabolic effects of insulin-like growth factors (IGFs) are modulated by a family of IGF-binding proteins (IGFBPs). Among the six known IGFBPs, IGFBP-5 is considered to play a role in bone formation. To investigate the effects of IGFBP-5 on bone mineral and matrix properties, femurs from transgenic mice overexpressing IGFBP-5 under the control of the osteocalcin promoter were evaluated by Fourier Transform Infrared Imaging (FTIRI). Analyses were done at the time of maximal osteocalcin expression (5 weeks). The spectroscopic parameters monitored were mineral-to-matrix ratio (indicative of the relative amount of mineral present), mineral crystallinity (index of the mineral crystal size and perfection) and collagen maturity (reflecting the ratio of non-reducible and reducible collagen cross-links). Multiple fields were selected for each femur, ranging from epiphysis to diaphysis. Previously, we showed that these transgenic mice display decreased osteoblastic function and osteopenia. In the present work, FTIRI showed that transgenic mice as compared to wild types have a different pattern of bone mineralization and matrix maturation. Specifically, cortical bone, primary spongiosa, and secondary ossification centers had lower values for mineral-to-matrix ratio and collagen maturity. Differences were not statistically significant in all cases although the trends were consistent. The mineral crystallinity did not vary significantly between the two groups, implying that the crystal maturation of mineral was not affected by IGFBP-5 overexpression. This study demonstrates that femurs from transgenic mice over expressing IGFBP-5 under the control of the osteocalcin promoter have modest alterations in mineral and matrix distribution, consistent with a role of IGF in osteoblast maturation.

Overexpression of insulin-like growth factor binding protein-5 decreases osteoblastic function in vitro.

Skeletal cells synthesize insulin-like growth factors (IGF) and their binding proteins (IGFBP). The effects of IGFBP-5 on bone cell growth and osteoblastic function are controversial, and transgenic mice overexpressing IGFBP-5 exhibit osteopenia. The mechanisms were not explored, and in this study, we investigated the effects of IGFBP-5 overexpression in MC3T3 cells in vitro. MC3T3 cells were transduced with a retroviral vector (pLPCX) or a vector directing IGFBP-5 transcription under the control of a constitutive promoter. Untreated MC3T3 cells expressed alkaline phosphatase, and osteocalcin mRNA 1 week after confluence and at 4 weeks of culture they formed mineralized nodules. IGFBP-5 overexpression delayed the appearance of alkaline phosphatase and osteocalcin mRNA, decreased type I collagen and osteopontin mRNA and alkaline phosphatase activity (APA), and inhibited the formation of mineralized nodules. IGFBP-5 caused a modest stimulation of DNA synthesis. In conclusion, overexpression of IGFBP-5 decreases osteoblastic function possibly by binding IGFs in the bone microenvironment.

Transgenic mice expressing selected insulin-like growth factor-binding protein-5 fragments do not exhibit enhanced bone formation.

Skeletal cells synthesize insulin like growth factors (IGF) and six IGF binding proteins (IGFBP). IGFBP-5 and fragments were reported to stimulate bone cell growth and parameters of osteoblastic function. We investigated the effects of IGFBP-5 1-162 and 1-193 on bone remodeling in transgenic mice overexpressing these fragments under the control of the osteocalcin promoter. Transgenic mice had normal appearance, weight, and bone mineral density. Static and dynamic histomorphometry revealed that transgenic mice overexpressing IGFBP-5 1-162 or 1-193 had normal trabecular bone volume, osteoblast and osteoclast number, and normal bone formation rate. MC3T3 cells transduced with retroviral vectors overexpressing IGFBP-5 1-235, 1-193, and 1-162 fragments displayed normal cell growth and maturation, and failed to enhance the expression of alkaline phosphatase, osteocalcin, and type I collagen mRNA when compared to cells transduced with vector alone. In conclusion, transgenic mice expressing IGFBP-5 1-162 and 1-193 in the bone microenvironment do not exhibit an obvious skeletal phenotype.

[Video-assisted thoracoscopic sympathectomy for the treatment of facial flushing: ultrasonic scalpel versus diathermy]. / Simpatectomía torácica por videotoracoscopia para el tratemiento del rubor facial: bisturí ultrasónica frente a diaterma.

OBJECTIVE: To evaluate the advantages of the ultrasonic scalpel compared to electrocoagulation in patients undergoing video-assisted thoracoscopic sympatholysis or sympathectomy for uncontrolled facial blushing. METHODS: Two hundred bilateral video-assisted thoracoscopic procedures to interrupt transmission in the thoracic sympathetic nerve were performed in 100 patients with incapacitating facial blushing. In 2 cases, the video-assisted approach was chosen because of pleural symphysis. The mean age of patients was 34 years (range: 15 to 67). The sympathetic chain was interrupted from the lower portion of the first thoracic ganglion through the third. RESULTS: All patients were discharged within 24 hours with the exception of one on whom an emergency thoracotomy had been performed. No complications were reported in the group in which a harmonic scalpel was used. One case of temporary Horner syndrome (4 months) and 3 cases of persistent chest pain (more than 2 weeks) were reported in the diathermy group. There were 9 cases of partial and asymptomatic pneumothorax that resolved without treatment or prolonged hospital stays. CONCLUSION: Dissection of the sympathetic nerve is accomplished more reliably and with better visualization with the ultrasonic scalpel. Peripheral lesions in lung parenchyma and adjacent tissues (intercostal vessels and nerves) are avoided, as is Horner syndrome, which can be caused by dispersion of heat. Use of the ultrasonic scalpel would also lead to a lower incidence of postoperative neuralgia.

Simpatectomía torácica por videotoracoscopia para el tratamiento del rubor facial: bisturí ultrasónico frente a diatermia / Video-assisted thoracoscopic sympathectomy for the treatment of facial blushing: ultrasonic scalpel versus diathermy

OBJETIVO: Valorar las ventajas de la utilización del bisturí ultrasónico frente a la electrocoagulación, en los pacientes operados de rubor facial incontrolable mediante simpaticólisis o simpaticotomía torácica por videotoracoscopia. MÉTODO: Se han realizado 200 interrupciones del simpático torácico bilaterales por videotoracoscopia en 100 pacientes afectados de rubor facial invalidante. Dos de ellas se realizaron mediante cirugía videoasistida por presentar sínfisis pleural. La edad media de los pacientes fue de 34 años (rango: 15-67). La cadena simpática fue interrumpida desde la porción inferior de T1 hasta T3 inclusives. RESULTADOS: Todos los pacientes fueron dados de alta en 24 h, a excepción del paciente en el que se realizó toracotomía de asistencia. En el grupo en que se utilizó el bisturí armónico no hubo complicaciones. En el grupo de diatermia hubo un caso de síndrome de Horner transitorio (4 meses) y tres casos de dolor torácico persistente (superior a dos semanas). En total, hubo 9 neumotórax parcelarios y asintomáticos que no requirieron tratamiento ni prolongaron la estancia hospitalaria. CONCLUSIONES: El bisturí ultrasónico permite una sección del simpático más firme y con mejor visualización. Evita lesiones periféricas en el parénquima pulmonar y tejidos adyacentes (vasos y nervios intercostales), así como el síndrome de Horner que se puede producir por efecto calorífico. Produciría también una menor incidencia de neuralgias posquirúrgicas (AU)