Upper respiratory tract diseases at a developmental age constitute a very important social issue. Most children at pre-school or early school age undergo chronical upper airways infections, especially in seasons other than summer. These infections result in nasal breathing impairment and a poorer oxygen supply to the system. Additionally, the toxic products of bacterial metabolism also destroy human immunological mechanisms. Intensive intellectual and physical development is a characteristic at the age of the evaluated children. Therefore, all factors which negatively influence the child´s system may result in irreversible physical and intellectual defects. The main reason for a predisposition to a frequent incidence of infections are anatomic defects of the upper respiratory tract. These defects are: nasal septum deviations, adenoid tissue hypertrophy, and congenital deformities of natural paranasal sinus ostia. The diagnostic opportunities of computer imaging, recently developing in a stepwise manner, can give us another view of the shape of the above-mentioned sinus ostia. Also, defining the degree of change and the site requiring surgical correction become possible. Contemporary opportunities for sinus surgery, and knowing the development process (6) has enabled widen the indications for surgery at the developmental age. This is particularly important as long as persistent ostial narrowing may produce permanent changes in the sinus mucosa, and even then surgery to improve sinus ventilation is not able to reverse these changes. Consequently, such procedures should be performed early enough to anticipate any of the chronic changes mentioned above.

Experimental sinus surgery performed upon animals has suggested the possibility of an inhibitory influence on facial skeleton growth following extensive damage in this area (4). Thus, paranasal sinus surgery performed at the developmental age must differ from that performed on adults. The procedures can be executed only by a fully-trained surgeon equipped with instruments adjusted to the size of the patient. The surgery can encompass only the area of the congenital defect. The complete operating procedure according to Stammberger or Wigand (7, 10) should not be carried out, unless there are important reasons (e.g. oncological).

The first stage is a complete endoscopic evaluation of the nasal cavities. In case there is a narrowing in the ethmoidal infundibulum area, it is necessary to remove the uncinate process. If Haller cells are present, their medial walls should be removed. The pneumatised middle nasal concha is fixed by removal of its lateral wall. In the event of cysts or polyps inside the sinuses, it is convenient to remove them too, remembering that the presence of a cyst itself is not an indication for surgery. Endoscopic control of the frontal duct requires particular caution due to the characteristic cilia movements in this region. The frontal sinus of a child, in a case of a pathological condition, should be opened from an exterior approach, carefully enough not to result in scarification of the above-mentioned region of the naso-facial ostium duct.

Surgical treatment of the sphenoid sinus can take place only in the event of pathological changes resulting in neurological or ophthalmologic disturbances. Surgery in this area is burdened with a high risk, and thus it can only be performed in highly qualified centres and on patients absolutely requiring this sort of treatment.

All post-operated sinuses should be irrigated with antibiotic solution for a sufficient period of time, followed by endoscopic check-up to verify the results of the surgery (1, 6).

This paper covers a thorough study of the clinical results of modified conservative lateral nasal wall plas-tic surgery at a developmental age. Particular attention has been drawn to the development of the facial cranium in children operated on before the 11^th year of age, and checked postoperatively after the14^th year of age.

There have been 121 endoscopically-guided lateral nasal wall and sinus ostium reconstructions in the Paediatric ENT Clinic of Warsaw Medical University between April 1996 and September 2002. All the operated patients were checked postoperatively at 3 weeks, 3 months and one year. Eighty-six patients were follow-ed up one year after surgery. Due to the recurrence of symptoms (nasal polyps) in a period shorter than a year after surgery, 6 children had reoperations. One child required repeating the surgery twice. A one year check-up revealed satisfactory clinical results in 71 children i.e. shortening of the infection period, less frequent incidence, and remission of accompanying symptoms (headaches, olfactory disorders). The age of the operated children was analysed. Particular attention was paid to those patients who were less than 11 years old at the time of surgery and over 14 years old at the check-up visit. There were 21 children fulfilling these criteria. None of them presented any impairment of craniofacial development, and there was observed no dis-proportion in the development of the operated and unoperated halves of the maxilla, ethmoidal labyrinth, or orbital elements.

Surgical treatment of congenital, post-traumatic, or chronical postinflammatory malformations of the sinuses is obligatory in patients at a developmental age. Leaving the deformation may lead to physical and mental retardation (2, 3). It can also result in persistent changes to the bronchi or the middle ear. All surgical procedures in children should be performed as conser-vatively as possible. Thus only 3 of our patients underwent the complete original operating procedure. These three cases concerned children with cystic fibrosis, and affected the whole mucous membrane of the nose and paranasal sinuses. Operations in other patients encompassed only the altered structures, so the procedure performed can be described as conservative and slightly invasive. According to the literature, other centres operating on children attain similar results (8, 9). Therefore, research applying complete sinus endoscopy procedures to animals, subsequently resulting in deformations in maxillar development, do not reflect the human case. This may be due to the fact that an animal´s nose develops in a different way from the human nose.

1.Endoscopic surgery improving sinus ventilation in children can be performed only in sufficiently equipped and trained centres.

2.The surgery must be as conservative as possible.

3.None of the patients operated on before the period of intensive craniofacial growth presented any signs of facial cranium development inhibition.

4.Lateral nasal wall endoscopic surgery in children requires consequent follow-ups performed by the operating centre, for many months.