Radiological Measurement Of The Osseous Distance Between The Uncinate Processes And Concha Media

Many factors are considered to be involved in the process of chronic rhinosinusitis. In recent years, as the extensive application of CT scans and advancement of endoscopic technology, doctors become more and more aware of the impact of structures of sinus ostia and adjacent areas on the occurrence of the disease. Now it can be clearly seen that several anatomical variations, such as a laterally or medially bent uncinate process, or elongated and enlarged uncinate processes, a paradoxically curved middle turbinate or a concha bullosa, would all effect a change in width of osseous middle meatus. The later are outflow passage of the majority of nasal sinuses. Wang RG et al suggested previously that in the postoperative cases, the distance between the residual uncinate processes and concha media should remain, at least, 5 mm or more, otherwise the patients tend to recur.Trying to elucidate whether the width of the osseous middle meatus has been changed in cases of chronic sinusitis, the minimal osseous distance between the uncinate processes and concha media was evaluated in patients with chronic sinusitis and controls with non-sinusitis by the radiological measurement.1. Materials and Methods1.1 Clinical MaterialsAll the CT scan materials were obtained from 844 cases that were clinically diagnosed as chronic sinusitis and confirmed by CT scans in the Department of Otorhinolaryngology of the Second Affiliated Hospital of Zhejiang University College of Medicine during the period from July 2001 to June 2004. Among them, 90 cases have preserved coronal scan films in computer with thickness of 2 mm every section. They were selected to examination. Of these 90 cases, 48 were male and 42 were female, aged from 18 to 72 years with mean age of 32.2 years. 30 cases of patients with non-sinusitis were informed consent and collected as controls, including 20 cases of sudden deafness and 10 cases of chronic otitis media, as well as mastoiditis. Among the 30 controls, 13 were male and 17 were female, aged from 25 to 65 years with mean age of 41.7 years.1.2 Radiological Materials90 cases of chronic sinusitis and 30 cases of controls underwent the same coronal CT scan of nasal sinuses with thickness of 2 mm every section. Only the candidates with non-sinusitis could be brought into the control group when there was not any opacity found in nasal sinuses on their CT scan films. The patients with chronic sinusitis were then divided into two groups after evaluation of their CT scan films, one is 33 cases of anterior sinusitis;the other is 57 cases of pansinusitis. The division depended on the opacifications of nasal sinuses within limits anterior to ground lamella of the middle turbinate or beyond the limits. 13 Parameters for Coronal CT ScansThe position of patients should be supine with their head extended extremely posteriorly. Gantry angulation was perpendicular to infraorbitomeatal line. The consecutive CT scans were then performed with thickness of 2 mm every section from the anterior nasal spine to the posterior border of sphenoidal sinus. The scanning plane was vertical to the hard palate. The scanner was set with a wide window setting of 400HU, centered at 40HU, and with 120 kv peak and 210 mA. Intravenous contrast medium was not administrated in both groups of chronicsinusitis and controls. 1.4 MeasurementThe osseous distance between the uncinate processes and concha media was measured. The uncinate processes appeared approximately at the tenth layer and disappeared at the twentieth layer, which means about 20 mm to 40 mm posterior to anterior nasal spine. On all these layers, which simultaneously demonstrated uncinate processes and concha media, their distances were measured. So 10~20 values could be obtained from each side every case. The minimal value was identified with the minimal osseous distance between uncinate processes and concha media.2. ResultsFor 90 cases of chronic sinutis, the mean value of the minimal osseous distances between the uncinate processes and concha media was 5.33 ±2.62 mm. For 30 cases of controls, that was 4.09+0.79mm. The difference between them was found statistically significant by t-test (P<0.01). They were shown in Table 1.Table 1 The mean values of cases with chronic sinusitis and non-sinusitis (mm)_ Number of Number of - +cn Groups _ . . _.. x Iau __________________Cases (n)______Sides________________Chronic sinusitis 90 180 5.33+2.62Non-sinusitis 30 60 4.09±0.79As mentioned above, among the 90 cases of chronic sinusitis, 33 cases are anterior sinusitis. Their mean measured value was 5.73+2.30mm. In addition to these, the mean measured value of 57 cases of pansinusitis was 5.09+2.77mm. The difference between the two groups, however, was not statistically significant (P>0.05), as shown in Table 2.3. DiscussionsIn the present investigation, we found that the minimal width of osseous middle meatus for cases of chronic sinusitis was even larger than it was for cases of controls. However, of the cases of chronic sinusitis, between the patients with anterior sinusitis and with pansinusitis, no statistically significant difference could be found. This suggested that the width of the osseous middle meatus of patients with chronic sinusitis appears to be not smaller but larger than that of those non-sinusitis controls.It is generally acknowledged that some anatomical variations of uncinate processes and concha media are closely associated with the width of the osseous middle meatus. We once presumed that the osseous distance between the uncinate processes and the concha media, identified with width of osseous middle meatus, in some cases would be smaller than in others, and these individuals would be tend to develop chronic sinusitis. However, this theoretical presumption was not confirmed by our present research. This indicates probably that there is not any narrowing of osseous middle meatus in cases of chronic sinusitis. The narrowing and blockage of middle meatus, which actually exist in cases of chronic sinusitis, could be caused predominately by swelling and packing of soft tissues. For this reason, we don't think it's necessary to remove some bony structures, such as the uncinate processes, during endoscopic surgery for cases of chronic sinusitis.In the traditional surgery for chronic sinusitis, it was essential to remove a part of concha media. But nowadays, in the modern functional endoscopic sinus surgery for the condition, resection of the uncinate processes becomes always the first step,while preservation of concha media is very emphasized. As soon as surgeons understand finally whether the structural narrowing of osseous middle meatus occurs, it will turn into a controversial issue as to the necessity of resecting uncinate processes. In the light of findings in our measurements, we thought, there may be several anatomical variations in some cases of nasal sinusitis, such as the abnormalities of uncinate processes, concha media or ethmoidal bulla. And these anatomical variations may really cause somewhat narrowing of the osseous middle meatus, which turns not only some individuals susceptible to chronic sinusitis but also the condition refractory. But the pathological alterations of soft tissues secondary to repeat occurrence of nasal sinusitis, such as the swelling, thickening and polypoid changes, may constrict and even pack the space of middle meatus. Dose the packing of the soft tissues widen the originally narrow osseous middle meatus? If this happened, theoretically, a difference in the width of the osseous middle meatus between patients with pansinusitis and anterior sinusitis should be observed. But actually, according to the data of examination, we didn't find a statistically significant difference between the two groups. This can be explained as the result subjected influences from several sides. The individual variance of the two groups of samples may be apparent very much. The number of cases may be too few to get a statistically appropriate conclusion. The experimental method may be not sensitive sufficiently to an accurate determination, or Coronary CT scan of nasal sinuses with 2 mm every section may be not thin enough to distinguish something from others. All of these problems remain to be resolved in the future research. Maybe a new stereo-tomography of three dimensions is a method accurate enough to the research.4. ConclusionsThe osseous distance between the uncinate processes and concha media in cases of chronic sinusitis may be not smaller than others with non-sinusitis.