RESUMEN
BACKGROUND AND PURPOSE: Biallelic constitutional mutations in DNA mismatch repair genes cause a distinct syndrome, constitutional mismatch repair deficiency syndrome (CMMRD), characterized by cancers from multiple organs, most commonly brain tumors, during childhood. Surveillance protocols include total and brain MR imaging among other modalities to enable early detection of tumors. Brain surveillance scans revealed prominent brain developmental venous anomalies (DVAs) in some patients. DVAs are benign vascular anomalies, and their incidence in the general population is 2.6%-6.4%. Most developmental venous anomalies are asymptomatic and are found incidentally. Our purpose was to assess the prevalence of DVAs in CMMRD patients and describe their phenotype. MATERIALS AND METHODS: A retrospective descriptive analysis of brain MR imaging studies from 10 patients from 3 families with CMMRD was performed. Analysis included the number of developmental venous anomalies, location, draining vessels, and associated vascular anomalies (ie, cavernomas), with clinical correlation of symptoms and tumors. RESULTS: All 10 patients had ≥2 developmental venous anomalies, and 2 had, in addition, non-therapy-induced cavernomas. There was no clinically symptomatic intracranial bleeding from developmental venous anomalies. Six patients had malignant brain tumors. The location of brain tumors was not adjacent to the developmental venous anomalies. No new developmental venous anomalies developed during follow-up. CONCLUSIONS: The occurrence of multiple developmental venous anomalies in all our patients with CMMRD suggests that developmental venous anomalies may be a characteristic of this syndrome that has not been previously described. If confirmed, this quantifiable feature can be added to the current scoring system and could result in early implementation of genetic testing and surveillance protocols, which can be life-saving for these patients.
Asunto(s)
Neoplasias Encefálicas/patología , Venas Cerebrales/anomalías , Neoplasias Colorrectales/patología , Síndromes Neoplásicos Hereditarios/patología , Neoplasias Encefálicas/diagnóstico por imagen , Neoplasias Encefálicas/genética , Venas Cerebrales/diagnóstico por imagen , Niño , Preescolar , Neoplasias Colorrectales/diagnóstico por imagen , Reparación de la Incompatibilidad de ADN , Femenino , Hemangioma Cavernoso del Sistema Nervioso Central/diagnóstico por imagen , Hemangioma Cavernoso del Sistema Nervioso Central/genética , Hemangioma Cavernoso del Sistema Nervioso Central/patología , Humanos , Lactante , Masculino , Síndromes Neoplásicos Hereditarios/diagnóstico por imagen , Fenotipo , Estudios RetrospectivosRESUMEN
Data on the clinical presentation of constitutional mismatch repair deficiency syndrome (CMMRD) is accumulating. However, as the extraintestinal manifestations are often fatal and occur at early age, data on the systematic evaluation of the gastrointestinal tract is scarce. Here we describe 11 subjects with verified biallelic carriage and who underwent colonoscopy, upper endoscopy and small bowel evaluation. Five subjects were symptomatic and in six subjects the findings were screen detected. Two subjects had colorectal cancer and few adenomatous polyps (19, 20 years), three subjects had polyposis-like phenotype (13, 14, 16 years), four subjects had few adenomatous polyps (8, 12-14 years) and two subjects had no polyps (both at age 6). Of the three subjects in the polyposis-like group, two subjects had already developed high-grade dysplasia or cancer and one subject had atypical juvenile polyps suggesting juvenile polyposis. Three out of the five subjects that underwent repeated exams had significant findings during short interval. The gastrointestinal manifestations of CMMRD are highly dependent upon age of examination and highly variable. The polyps may also resemble juvenile polyposis. Intensive surveillance according to current guidelines is mandatory.
Asunto(s)
Pólipos Adenomatosos/genética , Neoplasias Encefálicas/genética , Neoplasias Colorrectales/genética , Mutación , Síndromes Neoplásicos Hereditarios/genética , Adenosina Trifosfatasas/genética , Adolescente , Árabes/genética , Neoplasias Encefálicas/diagnóstico , Niño , Neoplasias Colorrectales/diagnóstico , Enzimas Reparadoras del ADN/genética , Proteínas de Unión al ADN/genética , Endoscopía Gastrointestinal , Femenino , Humanos , Poliposis Intestinal/congénito , Poliposis Intestinal/diagnóstico , Poliposis Intestinal/genética , Judíos/genética , Masculino , Endonucleasa PMS2 de Reparación del Emparejamiento Incorrecto , Proteína 2 Homóloga a MutS/genética , Síndromes Neoplásicos Hereditarios/diagnóstico , Fenotipo , Adulto JovenRESUMEN
Allogeneic hematopoietic SCT (HSCT) has been proposed as a treatment for patients with mitochondrial neurogastrointestinal encephalomyopathy (MNGIE). HSCT has been performed in nine patients using different protocols with varying success. Based on this preliminary experience, participants of the first consensus conference propose a common approach to allogeneic HSCT in MNGIE. Standardization of the transplant protocol and the clinical and biochemical assessments will allow evaluation of the safety and efficacy of HSCT as well as optimization of therapy for patients with MNGIE.
Asunto(s)
Trasplante de Células Madre/normas , Humanos , Seudoobstrucción Intestinal/genética , Seudoobstrucción Intestinal/cirugía , Encefalomiopatías Mitocondriales/genética , Encefalomiopatías Mitocondriales/cirugía , Distrofia Muscular Oculofaríngea , Oftalmoplejía/congénitoRESUMEN
Hematopoietic SCT (HSCT) from HLA-matched donors is sometimes complicated by GVHD or graft rejection, because of mismatched mHA. This study presents data suggesting the involvement of glutathione S-transferase theta-1 (GSTT1), a phase II detoxifying enzyme encoded by GSTT1, in Ab-mediated rejection of HSCT in children with congenital hemoglobinopathies (CHs). Mismatch of GSTT1, which often features a deletion polymorphism variant, can have major consequences in solid organ transplantation outcome. In liver transplantation, it has been shown to lead to de novo hepatitis, whereas in kidney transplantation, chronic allograft rejection has been documented. In this study on 18 children with CH who underwent HSCT, five cases of graft rejection occurred, all in GSTT1-null patients, four of which featured anti-GSTT1 antibodies. The data suggest that when GSTT1-null patients are transplanted with a GSTT1-positive graft, rejection due to an Ab-mediated immune response against GSTT1 displayed on transplanted stem cells may take place. Thus, it seems that detection of anti-GSTT1 antibodies in patients with a GSTT1-null genotype before transplantation may be predictive of graft rejection in the event of a GSTT1-positive donor.
Asunto(s)
Glutatión Transferasa/deficiencia , Rechazo de Injerto/enzimología , Supervivencia de Injerto/fisiología , Trasplante de Células Madre Hematopoyéticas , Hemoglobinopatías/enzimología , Hemoglobinopatías/cirugía , Niño , Preescolar , Glutatión Transferasa/genética , Glutatión Transferasa/inmunología , Rechazo de Injerto/genética , Rechazo de Injerto/inmunología , Supervivencia de Injerto/inmunología , Hemoglobinopatías/genética , Hemoglobinopatías/inmunología , Humanos , Lactante , MasculinoAsunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Recurrencia Local de Neoplasia/terapia , Neoplasias Primarias Secundarias/terapia , Leucemia-Linfoma Linfoblástico de Células Precursoras/terapia , Adolescente , Niño , Preescolar , Aberraciones Cromosómicas , Terapia Combinada , Irradiación Craneana , Femenino , Estudios de Seguimiento , Humanos , Inmunofenotipificación , Lactante , Israel , Masculino , Recurrencia Local de Neoplasia/genética , Recurrencia Local de Neoplasia/patología , Neoplasia Residual , Neoplasias Primarias Secundarias/genética , Neoplasias Primarias Secundarias/patología , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/patología , Pronóstico , Inducción de Remisión , Factores de Riesgo , Tasa de Supervivencia , Factores de Tiempo , Resultado del TratamientoRESUMEN
The aim of this pilot study was to determine VEGF serum levels (S-VEGF) at diagnosis and at restaging in children diagnosed with cancer, and to investigate whether this parameter provides prognostic information for remission after induction therapy and response to treatment. S-VEGF levels of 35 consecutive pediatric patients with various types of cancer were assayed at diagnosis and at restaging. Levels of VEGF were determined using a commercially available ELISA anti-human VEGF immunoassay kit. Thirty-one children went into complete remission or had a very good partial response to first-line therapy; 4 patients developed tumor progression. At diagnosis average S-VEGF level was 495 pg/mL (range, 0.89--2220 pg/mL) and at restaging it decreased to 118.36 pg/mL (range, 7.44--487 pg/mL). (p=.0039). The 4 patients with tumor progression had increased S-VEGF levels at restaging. The comparison between the levels of S-VEGF at diagnosis and at restaging showed a significant difference for the patients who responded to treatment with decreased S-VEGF and the patients who developed tumor progression with increased S-VEGF (p=.0019). One child with metastatic Ewing sarcoma developed progressive disease after several weeks, with significantly progressively higher S-VEGF levels. One child with Hodgkin disease, who had a higher level at first restaging and developed progressive disease, responded to reinduction therapy and had a significantly lower level at the second restaging. The child with metastatic hepatoblastoma responded to first-line chemotherapy with concomitant decrease in S-VEGF and alpha-fetoprotein levels, but developed local recurrence with elevation in both parameters. Changes in S-VEGF levels correlated with response to treatment for most of the children diagnosed with cancer. This provides a rationale for exploring clinical interest in S-VEGF measurements of a larger group of children with malignancies, and using the test for clinical trials of antiangiogenic therapies.
Asunto(s)
Biomarcadores de Tumor/sangre , Neoplasias/sangre , Factor A de Crecimiento Endotelial Vascular/sangre , Adolescente , Adulto , Niño , Preescolar , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Lactante , Masculino , Estadificación de Neoplasias/métodos , Neoplasias/diagnóstico por imagen , Neoplasias/terapia , Radiografía , Inducción de RemisiónAsunto(s)
Aberraciones Cromosómicas , Cromosomas Humanos Par 7/genética , Cromosomas Humanos Par 8/genética , Leucemia Promielocítica Aguda/genética , Adolescente , Cromosomas Humanos Par 15/genética , Cromosomas Humanos Par 15/ultraestructura , Cromosomas Humanos Par 17/genética , Cromosomas Humanos Par 17/ultraestructura , Cromosomas Humanos Par 7/ultraestructura , Cromosomas Humanos Par 8/ultraestructura , Resultado Fatal , Humanos , Masculino , Translocación GenéticaRESUMEN
A 12-year-old girl presented with arthritis, myalgia, anemia and positive ANA. Subsequently, she developed recurrent episodes of pulmonary hemorrhage, thrombocytopenia, CNS abnormalities, skin ulcers and diffuse calcinosis. This was followed by secondary antiphospholipid syndrome. Despite vigorous immunosuppression, the patient became bedridden. A peripheral blood stem cell autograft was offered when she developed pulmonary hypertension and digital ischemia at the age of 16 years. The post-transplantation course was uneventful. Liquefaction of calcinosis nodules with improvement of mobility occurred gradually. She is now 24 months post-transplant with no sign of disease activity and total disappearance of calcinosis nodules.
Asunto(s)
Enfermedades Autoinmunes/terapia , Calcinosis/terapia , Trasplante de Células Madre de Sangre Periférica , Anemia , Artritis , Calcinosis/diagnóstico por imagen , Calcinosis/etiología , Niño , Femenino , Fibromialgia , Humanos , Cintigrafía , Inducción de Remisión/métodos , Trasplante AutólogoRESUMEN
OBJECTIVES: To summarize and analyze the experience in CNS involvement (CNSI) in children with sarcomas treated in the above-mentioned institutions. PATIENTS AND METHODS: From 1990 to 2001, all medical charts were retrospectively reviewed: 19 sarcoma patients (12 boys and 7 girls) were diagnosed with CNSI (4 osteogenic sarcomas, 11 Ewing sarcomas, 2 rhabdomyosarcomas, 1 alveolar soft part sarcoma and 1 mesenchymal chondrosarcoma). Mean age of all patients at the time of initial diagnosis was 14.9 years (range: 4-24 years), mean age at the time when CNSI was diagnosed was 16.9 years (range: 5.5-27 years). RESULTS: The frequency of CNSI among our patients was 6.17%. The following symptoms and signs (sometimes combined) presented: headache (10 patients), nausea and vomiting (6 patients), seizures (11 patients) and focal neurological signs (9 patients). The mean duration of time elapsed since diagnosis of CNSI till death or last follow-up was 5.2 months (SD: +/-5.7 months). Four patients received chemotherapy (CT) alone, 8 CT and radiotherapy (RT), 2 RT alone, 3 supportive treatment only, 1 CT and surgery and 1 surgery alone. Sixteen patients died; there was no significant difference in the duration of survival between those who were treated with RT or surgery (mean +/- SD: 6.77 +/- 6.56 months) and those who received only CT or supportive treatment (mean +/- SD: 2.60 +/- 2.94 months) (p = 0.07). Brain disease was the main cause of death in all but 1 patient who died 4 days after autologous bone marrow transplantation from uncontrolled sepsis. In 16 patients, CNSI was part of a metastatic disease. CONCLUSIONS: Among children with sarcoma, CNSI is encountered in 6.17% of cases. More effective therapy has to be developed in order to improve their outcome.
Asunto(s)
Neoplasias del Sistema Nervioso Central , Sarcoma , Adolescente , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Neoplasias del Sistema Nervioso Central/diagnóstico , Neoplasias del Sistema Nervioso Central/epidemiología , Neoplasias del Sistema Nervioso Central/terapia , Quimioterapia Adyuvante , Niño , Preescolar , Femenino , Humanos , Israel/epidemiología , Masculino , Radioterapia Adyuvante , Sarcoma/diagnóstico , Sarcoma/epidemiología , Sarcoma/terapia , Análisis de Supervivencia , Resultado del TratamientoRESUMEN
This study evaluated preventive intervention designed to enhance the quality of life of children with cancer at the end-of-life, based on a theoretical model of crises denoted as the Perceived Personal Control Crisis Model. Preventive intervention on the Social Action level consists of introducing policies and services in the pediatric hemato-oncology department designed to enhance the quality of life of children with cancer at the end-of-life.
Asunto(s)
Neoplasias/terapia , Servicio de Oncología en Hospital/normas , Política Organizacional , Calidad de Vida , Cuidado Terminal/psicología , Actitud Frente a la Muerte , Aflicción , Niño , Niño Hospitalizado/psicología , Comunicación , Sedación Consciente , Intervención en la Crisis (Psiquiatría) , Toma de Decisiones , Miedo , Humanos , Modelos Teóricos , Cuidados Paliativos , Padres , Relaciones Profesional-Familia , Cuidado Terminal/normasRESUMEN
A new entity manifested by severe congenital neutropenia associated with osteoporosis and recurrent bone fracture is described in a family. A possible role for a new recognized cytokine system involved in bone remodeling, the osteoprotegerin/receptor activator of nuclear factor-kappa B ligand, is suggested.
Asunto(s)
Glicoproteínas/deficiencia , Neutropenia/genética , Osteoporosis/genética , Receptores Citoplasmáticos y Nucleares/deficiencia , Agammaglobulinemia/genética , Remodelación Ósea , Proteínas Portadoras/sangre , Células Cultivadas , Preescolar , Consanguinidad , Insuficiencia de Crecimiento/etiología , Fibroblastos/patología , Filgrastim , Fracturas Espontáneas/etiología , Genes Recesivos , Glicoproteínas/sangre , Factor Estimulante de Colonias de Granulocitos/uso terapéutico , Humanos , Inmunoglobulinas Intravenosas/uso terapéutico , Masculino , Glicoproteínas de Membrana/sangre , Neutropenia/congénito , Osteoporosis/complicaciones , Osteoprotegerina , Pancitopenia/genética , Pancitopenia/terapia , Linaje , Trasplante de Células Madre de Sangre Periférica , Ligando RANK , Receptor Activador del Factor Nuclear kappa-B , Receptores Citoplasmáticos y Nucleares/sangre , Receptores del Factor de Necrosis Tumoral , Proteínas Recombinantes , RecurrenciaRESUMEN
The aim of this study was to describe busulfan disposition in a pediatric population who underwent bone marrow transplantation (BMT). Busulfan administered dose was 1 mg/kg every 6 h for 4 days. Plasma determinations were performed after the first dosing at 0, 15, 30, 60, 90, 120, 180, 240, 300, and 360 min. A noncompartment analysis model for extravascular absorption was used for the pharmacokinetic analysis. To obtain the area under the concentration-time curve (AUC) within the "therapeutic window" of 1,000-1,200 microM x minutes a busulfan dose adjustment Was performed at the fourth dose. Forty-five busulfan pharmacokinetic analyses were performed in 34 children. Eleven children had their dose adjusted [1.19 +/- 0.14) mg/kg] at the fourth dose and the AUC was monitored at the fifth one. The mean AUC +/- SD after the fifth dose (998.1 +/- 189.2 microM x min) was different (p = .006)from that after the first dose (1 mg/kg) (687.63 +/- 166.43 microM x min). Six children had their first AUC into the "therapeutic window," 17 children had their dose adjusted [1.2 (+/- 0.22) mg/kg], but the "adjusted" AUC was not available. These data suggest that it may be reasonable to recommend a busulfan dose of 1.2 mg/kg to achieve the accepted therapeutic target in children undergoing BMT.
Asunto(s)
Antineoplásicos Alquilantes/farmacocinética , Trasplante de Médula Ósea , Busulfano/farmacocinética , Animales , Área Bajo la Curva , Niño , Preescolar , Relación Dosis-Respuesta a Droga , Monitoreo de Drogas/métodos , Humanos , Lactante , Estudios Prospectivos , Distribución TisularRESUMEN
Forty-one consecutive children with acute lymphoblastic leukemia (ALL) received prophylaxis therapy with the low molecular weight heparin (LMWH) enoxaparin during L-asparaginase treatment. Enoxaparin was given every 24 h subcutaneously at a median dose of 0.84 mg/kg per day (range, 0.45-1.33 mg/kg per day) starting at the first dose of L-asparaginase until 1 week after the last dose. Molecular analysis for thrombophilic polymorphisms documented prothrombin G20210A mutation in 3/27 (11%), homozygosity for MTHFR C677T mutation in 5/27 (18.5%, and heterozygosity for factor V Leiden mutation in 5/27 (18.5%) children. There were no thrombotic events during 76 courses of L-asparaginase in 41 patients who had received enoxaparin. One patient suffered brain infarct 7 days after enoxaparin was stopped. There were no bleeding episodes. In a historical control group of 50 ALL children who had not received prophylactic enoxaparin during L-asparaginase treatment, two had thromboembolisms (one deep vein thrombosis and one pulmonary embolism). Enoxaparin is safe and seems to be effective in prevention of thromboembolism in ALL patients during L-asparaginase therapy. This study provides pilot data for a future randomized trial of the use of LMWH during ALL therapy for the prevention of asparaginase-associated thrombotic events.
Asunto(s)
Anticoagulantes/administración & dosificación , Antineoplásicos/administración & dosificación , Asparaginasa/administración & dosificación , Enoxaparina/administración & dosificación , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Tromboembolia/prevención & control , Adolescente , Factores de Coagulación Sanguínea/genética , Niño , Preescolar , Análisis Mutacional de ADN , Quimioterapia Combinada , Femenino , Humanos , Incidencia , Lactante , Israel/epidemiología , Masculino , Proyectos Piloto , Polimorfismo Genético , Leucemia-Linfoma Linfoblástico de Células Precursoras/complicaciones , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Tromboembolia/etiología , Tromboembolia/genética , Trombofilia/tratamiento farmacológico , Trombofilia/etiología , Trombofilia/genéticaRESUMEN
Eosinophilic granuloma is a well-recognized form of Langerhans cell histiocytosis, most commonly involving the skull bones, usually with an excellent prognosis. Recurrent and difficult to recognize osteolytic lesions of the skull are encountered only rarely. A patient with recurrent eosinophilic granuloma of the skull is reported. In spite of appropriate multimodality treatment, there were several recurrences, most recently with involvement of the mastoid process. Imaging studies revealed extensive involvement of surrounding structures with expansion of the tumor into the middle cranial fossa and slight pressure on the antero-medial portion of the temporal lobe of the brain. Despite extensive involvement, the patient had no complaints. Because of the rarity of such silent and unpredictable lesions, a systematic approach with regular CT and MRI follow-up is suggested.
Asunto(s)
Granuloma Eosinófilo/patología , Apófisis Mastoides/patología , Niño , Terapia Combinada , Granuloma Eosinófilo/diagnóstico por imagen , Humanos , Neoplasias Maxilomandibulares/diagnóstico por imagen , Neoplasias Maxilomandibulares/patología , Masculino , Apófisis Mastoides/diagnóstico por imagen , Invasividad Neoplásica/diagnóstico , Invasividad Neoplásica/diagnóstico por imagen , Recurrencia , Neoplasias Craneales/diagnóstico por imagen , Neoplasias Craneales/patología , Tomografía Computarizada por Rayos XRESUMEN
Fluorodeoxyglucose (FDG), labeled with F-18, is a glucose analog that accumulates in cells in proportion to the rate of glucose metabolism, and increased carbohydrate metabolism has been recognized as a feature of malignant cells versus normal cells. In addition, it permits the detection of metastases not discovered by bone scan. Although detection of the primary site of disease is usually accomplished well with conventional techniques, the performance of FDG positron emission tomography (PET) may be useful to determine metastases that are not clinically evident. The authors describe a case of early detection of distant metastases by FDG-PET in a young patient diagnosed with rhabdomyosarcoma of the hand.
Asunto(s)
Fluorodesoxiglucosa F18 , Rabdomiosarcoma Embrionario/patología , Sarcoma/diagnóstico por imagen , Sarcoma/secundario , Adolescente , Brazo/patología , Terapia Combinada , Femenino , Mano/patología , Humanos , Cintigrafía , Rabdomiosarcoma Embrionario/diagnóstico , Rabdomiosarcoma Embrionario/terapia , Sarcoma/diagnósticoRESUMEN
We report on a case of late relapse of hepatocellular carcinoma in a child suffering from combined hepatoblastoma and hepatocellular carcinoma, stage IV. This is a rare event, as it has been accepted that a 5-year period free of any signs of disease in children suffering from malignant hepatic tumors is sufficient to classify such patients as survivors. In our patient, recurrence of the hepatocellular carcinoma component was diagnosed more than five years after the initial diagnosis. This case illustrates the need for more prolonged follow-ups for such children.
Asunto(s)
Carcinoma Hepatocelular/cirugía , Hepatoblastoma/cirugía , Neoplasias Hepáticas/cirugía , Recurrencia Local de Neoplasia , Neoplasias Primarias Múltiples , Carcinoma Hepatocelular/patología , Preescolar , Femenino , Humanos , Neoplasias Hepáticas/diagnóstico , Neoplasias Hepáticas/patología , Recurrencia Local de Neoplasia/patología , Factores de Tiempo , Tomografía Computarizada por Rayos XAsunto(s)
Anemia Hemolítica Autoinmune/complicaciones , Células Gigantes/patología , Hepatitis/complicaciones , Hígado/patología , Anemia Hemolítica Autoinmune/inmunología , Biopsia con Aguja , Resultado Fatal , Hepatitis/inmunología , Hepatitis/patología , Humanos , Inmunohistoquímica , Lactante , Masculino , FagocitosisRESUMEN
Atypical hemolytic uremic syndrome (HUS) is a heterogeneous group of disorders, the pathogenesis of which is unclear. Plasma transfusions and plasmapheresis are widely used modes of therapy for adults with this life-threatening syndrome. There is very limited experience in using plasmapheresis therapy in children and infants with atypical HUS. Plasmapheresis, which is considered a relatively safe procedure in adults and older children, may be hazardous in neonates and very young infants and can result in severe complications. We report a 2-month-old infant with idiopathic atypical HUS, who was successfully treated with a 1-month course of plasmapheresis during the acute phase of the disease. Appropriate preparations as well as several adjustments were made in order to meet the special needs of this very young infant who, to the best of our knowledge, is the youngest reported patient with atypical HUS to undergo plasmapheresis. Plasmapheresis therapy of the infant was not associated with any complications of the procedure and resulted in marked clinical improvement. We conclude that plasmapheresis in neonates and in very small infants is technically feasible, can be performed without major complications, and may be of benefit in individual cases.