Anatomical landmarks of the lateral nasal wall: implications for endonasal lacrimal surgery

Reference role of middle turbinate axilla in lacrimal sac localization assisted by computed tomographic dacryocystography-reference value of middle turbinate in locating lacrimal sac

BACKGROUND

The middle turbinate axilla (MTA) has always been used as a stable anatomic landmark for endoscopic surgeons to locate the lacrimal sac on the lateral nasal wall. Yet, little is known about whether the lacrimal sac size will affect the positioning effect of MTA on lacrimal sac. The aim of this study was to investigate the regularity of lacrimal sac size and lacrimal sac localization through the reference position of the MTA on computed tomographic dacryocystography (CT-DCG) images.

METHODS

A series of 192 endoscopic dacryocystorhinostomy (DCR) surgeries were performed. All the patients had been diagnosed as unilateral nasolacrimal duct obstruction and received CT-DCG examinations. According to the maximum transverse diameter of the lacrimal sac on CT-DCG, the patients were classified into three groups. Measurements were taken on CT-DCG parasagittal images.

RESULTS

The average distance from the sac superior fundus (SSF) to the MTA was 7.52 mm ± 3.23 mm, and it increased with the increase of the maximum transverse diameter of the sac among groups (p < 0.01). The average distance from the common canaliculus (CC) to the MTA was 3.95 mm ± 2.49 mm. No significant difference was observed among the groups (p = 0.11). The average distance from the CC to the SSF was 3.41 mm ± 1.31 mm, and it increased with the increase of the sac transverse diameter among groups (p < 0.01).

CONCLUSIONS

The lacrimal sac can be accurately located on the lateral nasal wall by the reference position of the MTA on CT-DCG images. The distance of the SSF to the MTA and the SSF to the CC is related to the lacrimal sac size. The relative position of the CC to the MTA is relatively stable on CT-DCG images, which make it possible to locate the lacrimal sac of different sizes and the corresponding nasal mucosa incision design in endoscopic DCR.

Lacrimal Sac Anterior Border-Maxillary Line Distance: Effect on Endoscopic Dacryocystorhinostomy (EDCR) Surgery Results and NLDO-SS Questionnaire

This study aimed to investigate the effect of the maxillary line (ML)-lacrimal sac anterior border (LSA) distance on the results of endoscopic dacryocystorhinostomy (EDCR) operation. The study was designed retrospectively. The distance between LSA and ML was measured from preoperative paranasal sinus computed tomography (PNSCT) images. Nasolacrimal duct obstruction symptom score (NLDO-SS) was calculated before and after surgery. The endoscopically proven of the transition of the 2% fluorescein drop instilled into the eye to the nasal passage accepted as a surgical success. 47 patients included in the study and eight of them underwent bilateral EDCR. The average age of the patients was 50.3 ± 14.8. The LSA-ML distance was 4.2 ± 1.0 mm in all patients. The duration of surgery was found as 38.1 ± 6.1 min for each side. The preoperative NLDO-SS mean was 54.9 ± 11.7 and 22.2 ± 12.1 postoperatively (p = 0.000, CI = 28.9-36.2). Six patients (11%) required revision surgery. A statistically significant high positive correlation was found between duration of surgery and LSA-ML distance (p = 0.000, r = 0.840). There was a significant negative correlation between the duration of surgery and postoperative NLDO-SS (p = 0.041, r = -0.276). The LSA-ML distance calculated in this study was found to be significantly associated with the decrease in the duration of surgery and the NLDO-SS score obtained after surgery. However, more valid results can be obtained if similar studies are carried out in larger samples containing a sufficient number of revision cases.

The Anatomy of the Frontal Process of the Maxilla in the Medial Wall of the Lacrimal Drainage System in East Asians

PURPOSE

To investigate the anatomical structure characteristics of the frontal process of the maxilla in the medial wall of the lacrimal drainage system for endoscopic dacryocystorhinostomy based on the cone-beam computed tomography images.

METHODS

One hundred eight sides of orbits were retrospectively evaluated in this study. The angulation and thickness of the frontal process of the maxilla in the medial wall of the lacrimal drainage system were measured and compared at 2 different levels: lacrimal sac level and nasolacrimal duct level. The vertical height between the 2 measurement levels was also measured. Data were compared between males and females.

RESULTS

The average angulation and thickness of the frontal process of the maxilla were found significantly larger at the lacrimal sac level than at the nasolacrimal duct level (83.1 ± 11.3° vs. 61.7 ± 10.9° and 2.7 ± 0.9 mm vs. 1.1 ± 0.4 mm) (p < 0.001). The vertical height between the 2 levels was significantly higher in males than in females (8.6 ± 1.8 mm vs. 7.8 ± 1.7 mm) (p = 0.015).

CONCLUSIONS

We found the angulation and thickness of the frontal process of the maxilla in the medial wall of the lacrimal drainage system decreased from the upper to the lower level. Starting the osteotomy during endoscopic dacryocystorhinostomy might be easier and safer at the midpoint level of the maxillary line.