Frontal Angle: A New Predictor of Difficulty in Endoscopic Frontal Sinus Surgery-A Preliminary Computed Tomography Study

OBJECTIVES

The possibility of visualization of the frontal sinus during endoscopic surgery depends on 3-dimensional configuration of the frontal sinus opening (FSO). We aimed to determine the prevalence of unfavorable angulation of the lower part of the posterior wall of the frontal sinus and its relation to FSO diameter.

METHODS

One hundred and twenty-eight computed tomography (CT) scans were retrospectively reviewed to measure (1) the angle between the nasal floor and the plane tangent to the posterior table of the frontal sinus above the most posterior aspect of the anterior buttress (frontal angle, FA) and (2) dimensions of the FSO.

RESULTS

The FA ranged from below 30° to 90°. Nearly 13% of sinuses (16.4% of patients) showed FA about 90°, which should enable good visualization of the sinus with the 30° scope after opening and clearing the frontal recess, while 4% (6.25% of patients) showed FA ≤ 30°. The anterior-posterior diameter (A-PD) was below 5 mm in 17.6% of sinuses (26.6% of patients). There was a significant correlation between FA and A-PD. Unfavorable combination of FA and A-PD (<45°, <5 mm) was present in 5.2% of sinuses (8.6% of patients), and extremely unfavorable combination (<30°, <5 mm) in 0.8% (0.8% of patients).

CONCLUSIONS

The FA shows great interindividual variability, which is very likely to reflect the possibility of inspection of the frontal sinus. This implies a need for further prospective clinical studies to validate FA as a predictor of difficulty in frontal sinus surgery.

The prognostic variables affecting the frontal sinusotomy patency outcome and how to manage: A prospective study

OBJECTIVES

The study aimed to assess the factors affecting the frontal sinus patency after endoscopic frontal sinusotomy.

DESIGN

A prospective cohort study.

SETTING

Tertiary centre hospital.

MAIN OUTCOME MEASURES

Fifty patients with refractory chronic frontal sinusitis (83 operated frontal sinuses) had frontal sinusotomy and followed up for six months. Multiple operative factors were included the type of the procedure, intraoperative sinus findings, degree of mucosal preservation and middle turbinate stability. Other factors were also assessed, including smoking, the presence of allergic rhinitis, asthma, gastroesophageal reflux and other associated medical comorbidities.

RESULTS

The sinus patency success rate was 75.9%. There was a significant difference regarding the intraoperative anteroposterior sinus ostium diameter (5.36 ± 1.45 mm vs 8.88 ± 2.38 mm, P-value: .001* in the failed group and the success group, respectively). There was a significant association between the patency outcome and the presence of associated medical comorbidities (P-value: .001*), the presence of allergic rhinitis (P-value: .001*), the degree of sinus mucosal preservation (P-value: .012*) and the degree of middle turbinate stability (P-value: .001*). The multivariate analysis showed that the intraoperative anteroposterior diameter of the sinus ostium, middle turbinate stability and presence of allergic rhinitis were significant predictors (P-value: .012*, .042* and .013*, respectively).

CONCLUSION

Sinuses with anteroposterior ostium diameters less than 5.36 mm are more susceptible to restenosis. The flail middle turbinate increases the risk of postoperative middle meatus synechia and frontal sinus patency failure. The presence of allergic rhinitis has a negative impact on the patency outcome.

The preoperative radiological findings associated with failure of frontal sinusotomy: A prospective study

OBJECTIVES

The study aimed to assess the association between the preoperative CT findings and the patency outcome of the frontal sinus after endoscopic frontal sinusotomy in the early follow-up period.

DESIGN

A prospective cohort study.

SETTING

Tertiary hospital centre.

MAIN OUTCOME MEASURES

The study measures the association between the frontal sinusotomy outcome and the standard preoperative radiological scores, including Harvard, Kennedy and Lund-Mackay. It also measures the impact of the degree of sinus mucosal thickness on the outcome. Furthermore, it measures the effect of the anteroposterior lengths of both the frontal sinus ostium and the frontal recess on postoperative frontal sinus patency.

RESULTS

Harvard, Kennedy and modified Lund-Mackay scores showed no evidence of association with the frontal sinusotomy patency outcome (P-values .397, .487 and .501), respectively. Still, the Lund-Mackay score showed a negative correlation with symptom improvement. Sinuses with a high-grade mucosal thickness on CT scan were associated with high failure rates (P-value: .009*). The anteroposterior length of the frontal sinus ostium significantly affects the outcome (P-value: .001*). In contrast, there was no association between the anteroposterior length of the frontal recess and the outcome (P-value: .965).

CONCLUSION

The Harvard, Kennedy and Lund-Mackay scores could not predict the frontal sinusotomy patency outcome. Failed cases were associated with advanced degrees of mucosal pathology in the preoperative CT scan. Sinuses ostia with anteroposterior diameters less than 5.36 mm showed more susceptibility for sinus restenosis postoperatively. The variability of the anteroposterior length of the frontal recess did not affect the surgical outcome.