| Research backgroundMaxillary bone fracture, a common injury in recent years, is often associated with trauma of other parts of the body, such as traumatic brain injuries, zygomatic arch, nasal bone and orbit fracture, and the mid-facial fracture which can lead to lacrimal path damage. According to statistics, about25-30%of patients with traumatic mid-face fractures were combined with lacrimal path damage, especially the Le Fort Ⅱ type fractures because of the fracture line crossing the frontal process of the maxillary bone, making canaliculi, lacrimal sac and nasolacrimal duct injuries common occurrences. The rate of lacrimal passage injury was as high as46.5%in the cases of fracture of nasal ethmoidal orbital area. Clinically, it was characterized by epiphora or pyorrhea. More frequently, these patients received initial treatments in the emergency department, so the lacrimal path injury characterized by epiphora was often ignored because the presence of the severe trauma such as concussion, skull base fracture. The diagnosis of lacrimal path damage is often delayed one or more weeks later after the injury. Moreover, difficulties in early, accurate diagnosis of lacrimal passage damage results in not a few misdiagnosis or delayed diagnosis cases. Therefore, if cases report ephiphora, we need to consider the possiblitiy of lacrimal passage damage. Signs of Epiphora are often associated with lacrimal passage damage. Lacrimal passage syringing and lacrimal duct probing are simple methods to detect the possible existence of lacrimal passage damage and preliminarily determine its site, extent and character, but they cannot display the situation on image. The lacrimal sac lipiodolography, which offers a precise size and shape of the lacrimal sac and often regarded as the first choice to evaluate the lacrimal passage before dacryocystorhinostomy (DCR), cannot display the anatomy surroundings. MR can show the anatomy of the lacrimal drainage system and the anatomy surroundings of the lacrimal sac more clearly, but cannot display the bony anatomy and small pipeline structure stably. Despite their merits, the methods mentioned above cannot display the lacrimal passage obstruction and the bony anatomy surrounding the lacrimal passage clearly on the same image simultaneously. CT scan has the advantages to display bony anatomy clearly, but cannot display the tiny lacrimal drainage system clearly on the same plane, whereas the lacrimal radioquaphy can display the lacrimal drainage system clearly. A combination of lacrimal radiography and CT scan, computed tomographic dacryocystography (CTDCG) has the advantages to display the tiny lacrimal drainage system and the bony anatomy clearly and simultaneously, thus enabling more accurate detection of lacrimal duct obstruction or the fracture of the lacrimal fossa(FS). Through the multiplanar reconstruction (MPR), curve planar reformation (CPR, maximum intensity projection (MIP) and three-dimensional reconstruction (3-d R),we can see the anatomic relationship more accurately from different directions to help making treatment decisions. This method applied in the diagnosis of patients with chronic dacryocystitis was reported, and it should be more valuable to assess the lacrimal passage injury caused by mid-face fractures, but rarely seen reported. Though the application of this method has been reported previously in the diagnosis of patients with chronic dacryocystitis, its role in assessing the lacrimal passage injury caused by mid-face fractures may be more valuable and thus needs to be accessed.The treatment experience of large cases of traumatic lacrimal passage damage ihasrarely been reported and remains controversial. Some scholars advocate early treatment to prevent lacrimal passage stricture and obstruction, while other scholars caution against undue intervention because the causes of epiphora may be simply local edema or oppression early after trauma and few lessons can be drawn from existing literature on treating traumatic lacrimal passage injury. Various methods exist for the treatment of chronic dacryocystitis, such as lacrimal passage probing, lacrimal passage irrigation, lacrimal laser therapy, high-frequency lacrimal forming treatment, lacrimal stent or artificial lacrimal intubation etc. However, the traumatic lacrimal passage injury is more clinically challenging because of the distortion of the lacrimal passage or the incarcerated displaced bone segments due to the fractures of frontal process of maxilla or the lacrimal bone. Dacryocystectomy (DCR) may be only selected at some cases. Endoscopic surgery, originated in the late1980s, with the advantages of better curative effect, minimally invasive and faster recovery, has been the general consensus of otolaryngology practitioners and got ophthalmologist’s approval. As one of the contemporary advanced technologies of nasal sector, it increasingly becomes a replacement to traditional lacrimal sac surgery. Zhou Bing (1994) reported for the first time in China that his clinical success rate reached91.5%in35cases of endoscopic dacryocystorhinostomy and the deflection of nasal septum and inferior turbinate hypertrophy can be easily healed with endoscopic which can lead to epiphora. Currently, this method is often used in the treatment of lacrimal duct injury caused by mid-face fractures. However, due to distortion or incarceration of the lacrimal passage in some traumatic lacrimal passage injury, it is more difficult to locate and expose the lacrimal sac when performing endoscopic dacryocystorhinostomy, and more easily to break the orbital lamina and increase the risks of orbital infection.Based on the characteristics and difficulties of the above diagnosis and treatment for traumatic lacrimal passage injury, this dissertation attempts to ascertain the diagnosis and treatment techniques from the following aspects:The first chapter:clinically, incidents of traumatic lacrimal passage injuries are often found primarily in traffic accident victims. The impact force of the prominent position such as nasal dorsum, base of nose and zygoma to the ground lead to fractures of the lacrimal bone and frontal process of maxillary bone, and hurt the lacrimal passage. The lacrimal fossa is not the immediate force location of trauma, the hurt force is derived from the force on the prominent position such as nasal dorsum,base of nose and zygoma, et al. But the bone of lacrimal passage area, thin and connected closely, is vulnerable to fracture and the lacrimal passage gets hurt indirectly.In order to simulate the occurrence of traumatic lacrimal passage injury, we established a digital virtual model using Mimics based on DICOM format CT data of a normal adult and observed the internal structure from different aspects. We transferred the model into Hypermesh and ABAQUS (finite element software), and established the finite element model of a skull-face bone. By simulating the situation of the impact force of the prominent position such as nasal dorsum, base of nose and zygoma to the ground, we ascertained the internal stress and displacement of the lacrimal passage, frontozygomatic suture and anterior-lateral wall of the maxillary sinus and provided the biomechanics basis for the traumatic lacrimal passage injury.The second chapter:DCR is a main method to treat the traumatic lacrimal passage injury. The key procedure of DCR is to locate and expose the lacrimal sac accurately. But it is very difficult to expose the lacrimal sac through the ordinary method by drilling open the front process of the maxillary bone, since the front process of the maxillary bone is very thick and prone to fracture shift. Meanwhile, it is easy to break the orbital lamina and make the orbital fat pop out, thus increasing the risk of orbital infection. We further explored the applied anatomy of DCR to look for a better procedure to expose the lacrimal sac. We found that the uncinate process (UP) is more frequently posterior to the lower part of the lacrimal fossa and the thickness of the low part of the lacrimal fossa is thinner than the upper part. Thus we proposed a lacrimal bone access anterior to the low part of the unciform process for lacrimal sac exposure in DCR and observed its feasibility. We found that this is a convenient, effective and minimally invasive method which can retain UP and mucous membrane and reduce trauma.The third chapter:28cases of traumatic lacrimal passage injury were retrospectively reviewed. Multiplanar reconstruction (MPR), curve planar reformation (CPR), maximum intensity projection (MIP) were performed and three-dimensional reconstruction (3-d R) on the extended brilliance workspace was done based on the CT scan data to observe the its value in the diagnosis and treatment.We found that lacrimal intubation, laser treatment and other minimally invasive treatment were infeasible because of the distortion or incarceration of the lacrimal passage. For the delayed cases, we performed DCR through the lacrimal bone access anterior to the lower part of the unciform process for lacrimal sac exposure(discussed in the second chapter), and observe its effectiveness. We proposed to decompress the lacrimal passage under endoscope after reduction of nasal bone and the front process of the maxillary bone. It can create conditions for minimally invasive treatment such as lacrimal intubation and laser treatment and assists in early evaluation of the feasibility.Chapter1The finite element analysis of lacrimal passage injuryObjective:IN order to simulate the occurrence of traumatic lacrimal passage injury, we established a digital virtual model using Mimics based on DICOM format CT data of a normal adult. We can observe the internal structure from different aspects.We transferred the model into Hypermesh and ABAQUS (finite element software), and established the finite element model of a skull-face bone. By simulating the situation of the impact force of the prominent position such as nasal dorsum, base of nose and zygoma to the ground, we can observe the internal stress and displacement of the lacrimal passage, frontozygomatic suture and anterior-lateral wall of the maxillary sinus, thus providing the biomechanics basis of the traumatic lacrimal passage injury.Method:1. Research object:A healthy male volunteer,25years old, height168cm, weight60kg. 2. Apparatus:(1) CT scanner:Philips Brilliance64spiral CT scanner(2) Lenovo ThinkPad X230i laptop(3) Software environment that Mimics10.01, Hypermesh and ABAQUS3. CT scanning parameter setting and scanning method:The subjects were in supine position, with median sagittal plane perpendicular to bed surface. The scanning range was from head to chin. Scanning conditions were as follows:tube voltage:140kV, tube current:250mAs, collimation:64mm x0.625mm, pitch0.5mm, width0.8mm, tube rotating period per cycle:0.33s.4. The finite element analysis:Construction of digital three-dimensional finite element model of maxillary complex:importing the scanned data of DICOM format into Mimics10.01software, by threshold segmentation automatically or manually, reconstructing the three-dimensional structure of maxillary complex, then exporting the data with point cloud format and reimporting into Hypermesh, assisted by grid processing and surface generation to form geometric models and reconfigure them, followed by importing the data into finite element analysis softwares (ABAQUS) and making impact text.5. Analysis items:To observe the feasibility of construction of three dimensional finite element model of craniofacial bone based on CT scanning DICOM formation data through Mimics, Hypermesh and ABAQUS.To observe the stress distribution and displacement around the lacrimal passage area, frontozygomatic suture and the anterior-lateral wall of maxillary sinus after indirect impact from the prominent positions such as nasal dorsum, zygomatic bone and nasal floor.Results:Based on CT scann data of craniofacial bone, a three dimensional finite element model including1209357nodes and283701units was established. The complicated shape of mid-face was duplicated, the macroscopic impressions on maxillary, zygomatic bone, maxillary sinus and orbital cavity was obtained(Fig.1-1, Fig.1-2).Given impact from the nasal floor, we saw stress contribution spreading to the frontal process of the maxillary bone, the anterolateral wall of the maxillary sinus, zygomatic arch, etc. The stress concentration was around the nose at2ms. Major stress concentration and displacement was seen around the frontal process of the maxillary bone, zygomatic arch and the anterolateral wall of the maxillary sinus (Fig.1-3～Fig.1-7). The greatest mises stress:the frontal process of the maxillary bone> the anterolateral wall of the maxillary sinus> frontozygomatic suture (Fig.1-16).Given impact from zygomatic bone, we saw stress contribution spreading to the frontozygomatic suture, the frontal process of the maxillary bone, the anterior wall and postier wall of the maxillary sinus, etc. The stress concentration was around the above areas at2ms, and was around the anterior wall and postier wall of the maxillary sinus, spreading to the other side at8ms (Fig.1-8～Fig.1-11). The stress contribution experienced a certain fall before reaching the stress peak. The greatest mises stress: the frontal process of the maxillary bone> the frontozygomatic suture> the anterolateral wall of the maxillary sinus (Fig.1-17).Given impact from the nasal dorsum, we saw stress contribution spreading along the nasal bone and the frontal process of the maxillary bone to ambitus evenly. The stress concentration was around the nasal dorsum and the inner wall of the orbit at2ms, and was around the piriform aperture and the lateral wall of orbit at8ms. The great displacement was around the nasal bone, the inner wall of the orbit and the frontal process of the maxillary bone, and spreading to the inferior wall of orbit, anteriorlaterior wall of the maxillary sinus at8ms (Fig.1-12～Fig.1-15). The stress contribution also experienced a certain fall before reached the stress peak. The greatest mises stress:the frontal process of the maxillary bone> the frontozygomatic suture> the anterolateral wall of the maxillary sinus (Fig.1-18).Conclusions:The application of Software Mimics, Hypermesh and ABAQUS in the construction of finite element model of maxillary complex is feasible and effective. This application can simulate traumatic environment on the model and provide the biomechanical basis for traumatic lacrimal passage injury.Through the model we can simulate the situation of traffic accident(the prominent position such as nasal dorsum, zygomatic bone and nasal floor impacting on the ground), bigger stress conduction can be observed around the frontal process of the maxillary bone (lacrimal passage area), where the bone, thin and connected closely, is prone to fracture.Chapter2Lacrimal fossa CT imaging anatomy and its value in dacryocystorhinostomyObjective:To explore the relationship between the uncinate process and the lacrimal fossa, we proposed a lacrimal bone access anterior to the uncinate process at the low part of the lacrimal fossa for lacrimal sac exposure in dacryocystorhinostomy, to provide operative guidance for the endoscopic dacryocystorhinostomy.Method:1. Research object:64-slice spiral CT data of80cases collected from October2011to December2013in our hospital, including chronic rhinitis65cases, deviation of nasal septum15cases, excluded nasal polyps, uncinate process malformation. Gender:40male,40female. Age:18to55years old, average (35.28±11.77) years.2. Apparatus:(1) CT scanner:Philips Brilliance64spiral CT scanner(2) Image post-processing workstation:Extended Brilliance Workspace(3)16cases of specimen from anatomy teaching and research section(4) surgery small round blade, knife, drill, bone shears, bone chisel and nasal endoscopic instrument(5) measuring tools such as vernier caliper3. CT scanning parameter setting and scanning method: The subjects were in supine position, with median sagittal plane perpendicular to bed surface. The scanning range was from the upper margin of the orbit to hard palate. Scanning conditions were as follows:tube voltage:140kV, tube current:250mAs, collimation:64mm×0.625mm, pitch0.5mm, width0.8mm, tube rotating period per cycle:0.33s.4. Post-processing:Multiplanar reconstruction was performed under extended brilliance workspace V4.5. The depth of lacrimal fossa (the straight distance from anterior lacrimal crest to the posterior lacrimal crest) was measured on the axis image, the length of lacrimal fossa (the straight distance from the lacrimal sac fossa top to bottom) was measured on the coronary image, Each measuring was undertaken twice and the results were then averaged.5. Simulate the endoscopic dacryocystorhinostomy on specimens:A u-shaped mucosal flap in front of the UP about1.5cm x1.0cm hinged superiorly as the centre of the operculum of the middle turbinate (OMT) was made to expose the frontal process of the maxillary bone and the lacrimal bone(LB). The junction between the maxillary and the lacrimal bone(MB-LB) was easy to identify. The LB was first nibbled away inferiorly then upward to expose the entire lacrimal sac. A lacrimal probe was inserted to the lacrimal sac through the lower lacrimal puncta and the lacrimal sac was cut open in the front. The thickness of inner walls of anterosuperior and posteroinferior part of lacrimal fossa was measured.6. Analysis Items:The anatomical relationship of the lacrimal fossa (FS) to the operculum of the middle turbinate (OMT), lacrimal bone (LB) and uncinate process (UP) were observed.The depth of lacrimal fossa (the straight distance from anterior lacrimal crest to the posterior lacrimal crest) was measured on the axis image, the length of lacrimal fossa (the straight distance from the lacrimal sac fossa top to bottom) was measured on the coronary image. The thickness of inner walls of anterosuperior and posteroinferior part of lacrimal fossa was measured during DCR.7. Statistical analysis:The data were analyzed using SPSS13.0, the data about the thickness of inner walls of anterosuperior and posteroinferior part of lacrimal fossa being recorded with the mean±standard deviation (x±s). Paired samples t test was administered, with P <0.05for statistical significance.Results:The length of lacrimal fossa (FS) was (12.210±2.030)mm, the depth of the lacrimal fossa was (6.359±1.222)mm. No gender difference was found in samples. The bone window size should be consistent with it to fully expose the lacrimal sac during DCR. The anatomical relationship of the lacrimal fossa (FS) to the uncinate process (UP):At the lower level, the UP was adjacent to the orbital lamina(62.5%), lacrimal fossa(31.2%)and the frontal process of maxillary bone(6.3%); at the middle level, the UP was adjacent to the orbital lamina(55.0%), lacrimal fossa(30.0%), the frontal process of maxillary bone(10.0%) and lateral wall of the middle turbinate(5.0%); at the upper level, the UP was adjacent to the orbital lamina(47.5%), lacrimal fossa(25.0%), the frontal process of maxillary bone(12.5%) and lateral wall of the middle turbinate(15.0%). It provided surgery guidance for a lacrimal bone access anterior to the lower part of the unciform process for lacrimal sac exposure in DCR.Dacryocystorhinostomy was performed on16specimen through lacrimal bone access anterior to the lower part of the unciform process for lacrimal sac exposure, causing no orbital lamina damage. The bony thickness of the anterosuperior part of lacrimal fossa (FS) was (2.962±0.330)mm, while the bony thickness of the posteroinferior part was (0.021±0.005)mm (t=35.33, P<0.05). It suggested that the thickness of the lower part of the lacrimal fossa is thinner than the upper part. It was convenient, effective and minimally invasive to take a lacrimal bone access anterior to the low part of the unciform process for lacrimal sac exposure in DCR which could retain UP, mucous membrane and reduce trauma. Conclusions:The anterosuperior part of the lacrimal sac fossa corresponding to the frontal processes of the maxillary bone is thicker than the posteroinferior part corresponding to lacrimal bone. It is easy to knot open the lacrimal bone first posteroinferior when performing DCR.The uncinate process was more frequently posterior to the lacrimal fossa at the lower level, then adjacent to lacrimal bone or the frontal process of maxillary bone at the intermediate level, last adjacent to the lateral middle turbinate or orbital lamina at the upper level. When performing dacryocystorhinostomy, we should first nibble the LB away inferiorly then superiorly to the lacrimal sac top above the OMT, allowing enough space to expose the lacrimal sac in front of the UP, which retains UP and mucous membrane and reduce trauma. Accurate reproduction of the anatomic relationship of UP and lacrimal fossa helps to improve the efficacy of surgery and avoid complications.Chapter3Computed tomographic dacryocystography and endoscopic surgery to traumatic lacrimal passage injuryObjective:To explore the diagnosis, treatment methods and opportunity in lacrimal passage injury combined with mid-face fractures, and evaluate the diagnostic utility of computed tomographic dacryocystography (CTDCG) to provide operative guidance for the endoscopic DCR. To observe the feasibility for lacrimal sac exposure in dacryocystorhinostomy by lacrimal bone access anterior to the lower part of the unciform process.Method:1. Research object:28cases with lacrimal passage injury combined with mid-face fractures hospitalized in our hospital from February2007to October2012were reviewed.20males and8females. The age range is from18to55years, average being (38.45±5.27) years. Diagnostic criteria:The patients were diagnosed as below:epiphora or pyorrhea associated with mid-facial fracture caused by trauma, blockage of lacrimal pathway or no liquid flow in the nasal cavity after the flush of the canaliculus lacrimalis. The bottom of the lacrimal sac or the lacrimonasal duct was unreachable in the probing of lacrimal passage due to compression of lacrimal sac or lacrimonasal duct. Compression of the lacrimal sac or the nasolacrimal duct by fracture chips was displayed by Multi-slice spiral CT dacryocystography with3-d R. No history of epiphora.Patient group:Less than4weeks group:disease course from1day to4weeks;More than4weeks group:disease course from4weeks to24weeks.2. Apparatus:(1) CT scanner:Philips Brilliance64spiral CT scanner(2) Image post-processing workstation:Extended Brilliance Workspace(3) the Olympus nasal endoscopic surgery system, nasal gun-shaped forceps, nasal septum stripping, mucosal knife, small circular knife, reverse rongeur, mucous membrane cutting pliers, bone chisel, et al.(4) the lacrimal passage probe and surgical instruments(5) eye syringing needle(5ml)(6) contrast agent:Ominipaque solution (300mg/ml)(7) canaliculi silicone tube(8) lacrimonasal duct silicone tube.3. CT scanning parameter setting and scanning method:The patients were in supine position, with median sagittal plane perpendicular to bed surface, underwent CT scan before and after dacryocystography. The scanning range was from the upper margin of the orbit to hard palate. Scanning conditions were as follows:tube voltage:140kV, tube current:250mAs, collimation:64mm×0.625mm, pitch0.5mm, width0.8mm, tube rotating period per cycle:0.33s.4. Post-processing: The following reconstruction techniques after scanning including curved plane reconstruction (CPR), maximum intensity projection(MIP) and three-dimensional reconstruction (3-d R) were processed on an extended brilliance workspace V4.5. The distance between the top and bottom of dacryocyst to the opercule of the middle turbinate (OMT) was measured.5. Operation methods:Under general anesthesia or regional anesthesia, the patients first received closed nasal bone and maxilla frontal process fracture reduction under endoscope, then received canaliculus intubation or lacrimonasal intubation according to the block site. If intubation was not possible due to the compression of the fractures, lacrimal passage decompression was needed. After decompression, canaliculus intubation or lacrimonasal intubation was attempted again. If intubation was still not possible, dacryocystorhinostomy was recommended.(1) Canaliculus intubation procedures:a8#wire feeding needle was passed from superior lacrimal punctum through lacrimal sac and lacrimonasal duct to inferior nasal meatus. Through the inferior meatus, guided by the8#wire feeding needle, a artificial tube was implanted from lacrimonasal duct into canaliculus, out of the superior lacrimal punctum, then from the low lacrimal punctum, through the lacrimal sac and lacrimonasal duct to inferior nasal meatus by the same way. Knot the two ends in the nasal meatus in order to fix the artificial tube. Patients receive a topical antibiotic drop of tobramycin0.3%and dexamethasone0.1%(Tobradex, Alcon, Fort Worth,U.S.A.)4times a day for7days.(2) nasolacrimal duct intubation procedures:a8#wire feeding needle was passed from superior lacrimal punctum, through lacrimal sac and lacrimonasal duct, to inferior nasal meatus. Through the inferior meatus, guided by the8#wire feeding needle, a lacrimonasal duct silicone tube was implanted from inferior meatus into lacrimal sac. The post-surgery treatment was the same as mentioned in (1).(3)Lacrimal passage decompression procedures:The nasal mucosa was decongested with oxymetazoline spray. The lateral wall of the nose was infiltrated with local anesthetic (2%lidocaine with1:100,000epinephrine). Soaked neurosurgery pledgets with phenylephrine0.25%and lidocaine3%were used as a vasoconstrictor of the nasal mucosa. Under nasal endoscope a u-shaped mucosal flap was made in front of the UP about1.5cm×1.0cm hinged superiorly as the centre of the operculum of the middle turbinate (OMT) to expose the frontal process of the maxillary bone and the lacrimal bone(LB). Generally the fractured lacrimal bone was easy to be identify. Fractures with displaced bone segments were removed. Then the canaliculus was syringed, then the mucosal flap was restored, followed by gelatin sponge packing. The post-surgery treatment was the same as mentioned in (1).(4) dacryocystorhinostomy procedures:Under nasal endoscope, a u-shaped mucosal flap was made in front of the UP about1.5cm×1.0cm hinged superiorly as the centre of the operculum of the middle turbinate (OMT) to expose the frontal process of the maxillary bone and the lacrimal bone(LB). Generally the fractured lacrimal bone was easy to be identify. The fractures with displaced bone segments and part of the frontal process of the maxillary bone was removed. The LB was nibbled away inferiorly then superiorly to reach the lacrimal sac top above the OMT. The lacrimal sac was opened vertically with the crescent blade as "]"shape on the left side ("[" shape on the right side), creation of posteriorly hinged lacrimal sac and nasal mucosal flaps with silver clip clamps (the posteriorly hinged lacrimal sac was anastomosed to nasal mucosal flaps with silver clip clamps, with gelatin sponge filling the cavity. The post-surgery treatment was the same as mentioned in (1). All patients were subsequently followed up for6to12months.6. Determination of the curative effects:Cure:no epiphora with patent lacrimal passage6months after treatment; irrigation test shows the lacrimal passage is patent;Effective:occasional epiphora with limited patency of lacrimal passage6months after treatment;Ineffective:epiphora not improved.7. Analysis Items:The morphology of dacryocyst was observed and the location of fracture and lacrimal passage obstruction were determined. The distance between the top and bottom of dacryocyst to the OMT was measured. The feasibility of lacrimal bone access anterior to the lower part of the unciform process for lacrimal sac exposure in DCR was observed.The curative effects of the two groups were observed.8. Statistical analysis:The data were analyzed using SPSS13.0.The data about the distance between the top and bottom of dacryocyst to the OMT were recorded with the mean±standard deviation (x±s), followed by paired samples t test, with P<0.05for statistical significance. The data about the curative effects were recorded with percentage, followed by the administration of Fisher’s Exact Test (four table data), with P<0.05for statistical significance.Results:1. The displacement fracture of the lacrimal fossa and block site of the lacrimal passage could be displayed clearly by CTDCG with MPR, MIP, VR and3-d R.6cases of canaliculus obstruction,14cases of lacrimal sac obstruction,8cases of lacrimonasal duct obstruction were showed (Fig.3-1-Fig.3-6).2. The distance between the top and bottom of dacryocyst to the OMT were6.679±0.859mm,4.943±0.628mm (t=12.312, P=0.000) respectively. The former was greater than the latter. The OMT was located a little more than halfway down the lacrimal sac.3. It was feasible for lacrimal sac exposure in dacryocystorhinostomy by lacrimal bone access anterior to the lower part of the unciform process. The average duration of operation was55.6±10.5min, with no ensuing orbital lamina damage.4. The results included complete cure(18cases,64.29%):no epiphora with patent lacrimal passage; improved (5cases,17.86%):occasional epiphora with limited patency of lacrimal passage; and no effect (5cases,17.85%). There is a higher rate of recovery in the patients with1d-4w disease course than in patients with4w±24w disease course [94.73%(18/19)vs55.56%(5/9), p<0.05](Tab.3-1).Conclusions:1. Computed tomographic dacryocystography(CTDCG) is a useful diagnostic tool for lacrimal passage injury combined with mid-face fractures. 2. The opercule of the middle turbinate(OMT) is located a little more than halfway down the lacrimal sac. It is appropriate to nibble open the lower part of lacrimal sac fossa, then surpass the OMT above1time the distance to expose the lacrimal sac completely in DCR.3. Lacrimal passage decompression is a useful technique to deal with traumatic lacrimal passage injury. It creates conditions for canaliculus or nasolacrimal duct intubation, contribute to the early treatment of and rehabilitation of traumatic lacrimal passage injury.4. It is a simple, safe and effective technique to expose the lacrimal sac through lacrimal bone access anterior to the lower part of the unciform process in DCR, especially suitable to locate and expose the lacrimal sac in the cases of the lacrimal passage injury combined with mid-face fractures.5. Early treatments such as lacrimal sac decompression, canaliculus intubation and lacrimonasal duct intubation have good effects on patients with traumatic lacrimal passage damage.General conclusions:1. The application of Software Mimics, Hypermesh and ABAQUS in the construction of finite element model of maxillary complex is feasible and effective to simulate traumatic environment on the model and thus provide the biomechanical basis of traumatic lacrimal passage injury. By simulating the situation of traffic accident(the prominent positions such as nasal dorsum, zygomatic bone and nasal floor impacting on the ground) with this model, visible stress contribution and displacement can be observed around the frontal process of the maxillary bone (the lacrimal passage area),, which is bigger than that of the frontozygomatic suture and the anterior-lateral wall of maxillary sinus, where the thin and closely connected bones are prone to fracture.2. The anterosuperior part of the lacrimal sac fossa corresponding to the frontal processes of the maxillary bone is thicker than the posteroinferior part which corresponding to lacrimal bone. The uncinate process was more frequently posterior to the lacrimal fossa at the lower level, then adjacent to lacrimal bone or the frontal process of maxillary bone at the intermediate level, last adjacent to the lateral middle turbinate or orbital lamina at the upper level. When performing DCR, it is easy to nibble the LB away inferiorly then superiorly to the lacrimal sac top above the O... |
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