With the rapid development of new instrumentation it is now possible to carry out interventional procedures on ever younger children and even on neonates. As sedation and anaesthesia are also safer they can be utilised more freely. Physiological parameters such as respiration and circulation can be monitored closely throughout the whole procedure.
In our 15 years of experience we have undertaken 357 procedures on 125 children (Tab. [1
In children interventional diagnostic procedures are only performed when all other methods of reaching a diagnosis have been exhausted and when a final histological diagnosis is required to determine treatment.
Ultrasound guided therapeutic interventional procedures may also be carried out in certain clinical circumstances where the alternative would be operative intervention e. g. the drainage of intra-abdominal abscesses or peritoneal fluid collections. In many cases this will provide a definitive cure.
Indications for parenchymal biopsy of the solid organs within the abdomen are:
Indications for parenchymal biopsy of the solid organs within the abdomen are:
Liver:
Kidney:
To maximise safety the following criteria should be fulfilled:
An accurate clinical diagnosis, if possible
Appropriate haematological status -exclusion of anaemia, haemophilia or thrombocytopaenia
Acceptable blood-clotting factors
Available cross matched blood for transfusion, if necessary
Suggested Instruments and Procedure
Suggested Instruments and Procedure
Automated biopsy devices are preferred for the biopsy of solid abdominal organs because of their ease and speed of use and relative safety. In children the smallest needle possible should be used but this must be large enough to obtain an adequate sample. Needles smaller than 18 gauge do not usually provide an adequate enough sample for a histological diagnosis to be made. In our experience the Tru-Cut needle satisfies the conditions best for these procedures in children.
Our practice is to use an 18 gauge Tru-Cut biopsy automated device under ultrasound guidance using a biopsy guide on the transducer. The procedure can be performed in the operating theatre, if required.
In children general anaesthesia should usually be used to avoid involuntary movement.
Biopsies should be taken between 2 breaths with suspended ventilation. The anaesthetist is able to manually ventilate the child allowing the procedure to be performed in the 20-45 s pause between ventilations. Using this technique we have not observed any damage to the solid abdominal organs. At least 3 samples should be taken, 2 for light-microscopy and 1 for electron microscopy. In practice we may perform between 1 and 6 passes. Patients are monitored regularly at 1, 3, 6 and 24 h following the biopsy.
Our technique for draining abnormal fluid collections varies. For pleural fluid collections we use a catheter of 2.5 to 3.0 mms diameter in infants and 14, 16 or 20 gauge for older children whereas for abdominal, pelvic or retroperitoneal abscesses a 16-18 gauge catheter is used. The catheter is left in situ and if appropriate antibiotics are instilled through it into the abscess collection. In cases of pancreatic pseudocysts a pig-tail type catheter or peritoneal dialysis set may be used
Success Rates
Success Rates
A high level of success for both biospy and drainage procedures has been achieved (Tab. [2
Possible Complications and their Prevention
Possible Complications and their Prevention
Bleeding around the capsule after renal biopsy
Bleeding under the capsule or along the biopsy pathway after liver biopsy
Avoidance of incidental haemangiomata in the liver and the use of colour Doppler is recommended
Checking immediately after the biopsy then after 1, 3, 6 and 24 hours allows detection of bleeding as well as monitoring the effects of some therapeutic interventions. For documentation purposes a photographic record of these post-procedure assessments is kept
The incidence of complications is low (Tab. [3
Conclusion
Conclusion
In our series the clinical indications for interventional procedures have been intrahepatic cholestasis with portal fibrosis, hepatic tumours such as hepatoblastoma, some at a very early age, chronic persistent hepatitis, Niemann-Pick storage disease, giant cell hepatitis, blood clot within a gall bladder, ovarian tumours, neuroblastoma and various other tumours as well as varying intra-abdominal abscesses requiring drainage.
Taking "safety first" as our most important consideration we have had very few major complications in our cases. We have detected some capsular, subcapsular or perirenal haemorrhages which have however disappeared within 24 hours and could not be observed at follow up. We have had no major complications.
It should be emphasized again that ultrasound guided interventional procedures in children should always be carried out with great care. The use of general anaesthesia minimises complications and this is a significant difference in practice between adults and children.
