Recent progress in the treatment of intractable sialolithiasis / 北京大学学报(医学版)

Sialolithiasis occurs in approximately 0.45% to 1.20% of the general population. The typical clinical symptom manifests as a painful swelling of the affected glands after a meal or upon salivary stimulation, which extremely affects the life quality of the patients. With the development of sialendoscopy and lithotripsy, most sialoliths can be successfully removed with preservation of the gland. However, sialoliths in the deep hilar-parenchymal submandibular ducts and impacted parotid stones located in the proximal ducts continue to pose great challenges. Our research center for salivary gland diseases (in Peking University School and Hospital of Stomatology) has used sialendoscopy for 17 years and treated >2 000 patients with salivary gland calculi. The success rate was approximately 92% for submandibular gland calculi and 95% for parotid calculi. A variety of minimally invasive surgical techniques have been applied and developed, which add substantial improvements in the treatment of refractory sialolithiasis. Further, the radiographic positioning criteria and treatment strategy are proposed for these intractable stones. Most of the hilar-parenchymal submandibular stones are successfully removed by a transoral approach, including transoral duct slitting and intraductal basket grasping, while a small portion of superficial stones can be removed by a mini-incision in submandibular area. Impacted stones located in the distal third of parotid gland ducts are removed via "peri-ostium incision", which is applied to avoid a cicatricial stenosis from a direct ostium incision. Impacted parotid stones located in the middle and proximal third of the Stensen's duct are removed via a direct mini-incision or a peri-auricular flap. A direct transcutaneous mini-incision is commonly performed under local anesthesia with an imperceptible scar, and is indicated for most of impacted stones located in the middle third, hilum and intraglandular ducts. By contrast, a peri-auricular flap is performed under general anesthesia with relatively larger operational injury of the gland parenchyma, and should be best reserved for deeper intraglandular stones. Laser lithotripsy has been applied in the treatment of sialolithiasis in the past decade, and holmium ∶YAG laser is reported to have the best therapeutic effects. During the past 3 years, our research group has performed laser lithotripsy for a few cases with intractable salivary stones. From our experiences, withdrawal of the endoscopic tip 0.5-1.0 cm away from the extremity of the laser fiber, consistent saline irrigation, and careful monitoring of gland swelling are of vital importance for avoidance of injuries of the ductal wall and the vulnerable endoscope lens during lithotripsy. Larger calculi require multiple treatment procedures. The risk of ductal stenosis can be alleviated by endoscopic dilation. In summary, appropriate use of various endoscopy-assisted lithotomy helps preserve the gland function in most of the patients with refractory sialolithiasis. Further studies are needed in the following aspects: Transcervical removal of intraglandular submandibular stones, intraductal laser lithotripsy of impacted parotid stones and deep submandibular stones, evaluation of long-term postoperative function of the affected gland, et al.

Three-dimentional radiographic features of 67 maxillary radicular cysts / 北京大学学报(医学版)

OBJECTIVE@#To analyze the three-dimensional radiographic characteristics of maxillary radi-cular cysts using cone-beam computed tomography (CBCT) and spiral CT.@*METHODS@#Clinical records, histopathological reports, and CBCT or non-enhanced spiral CT images of 67 consecutive patients with maxillary radicular cysts were retrospectively acquired, and radiographic features, including size, shape, expansion, internal structure and relationship with the surrounding tissues, were analyzed. The lesions were divided into three types according to the involved tooth number, as follows: type Ⅰ (single tooth), the epicenter of the cyst was located at the apex of a nonvital tooth, without involvement of the neighbo-ring tooth; type Ⅱ (adjacent tooth involvement), the cyst was located at the apex of a nonvital tooth with involvement of the mesial and/or distal tooth root; and type Ⅲ (multi-teeth), the cyst involved the apexes of ≥4 teeth. Besides, these cysts were classified as another three types on sagittal views, as follows: centripetal, the root apex was oriented centripetally to the center of the cyst; palatal, the cyst was located mainly at the palatal side of the apex; and labial/buccal, the cyst was located mainly at the labial/buccal side of the apex.@*RESULTS@#Totally, 67 patients with maxillary radicular cysts were acquired, including 38 males and 29 females, and their ages ranged from 13 to 77 years. Among them, 46 lesions (68.7%) were located in the anterior maxilla and 65 (97.0%) were round or oval. Labial/buccal cortex expansion was present in 43 cases (64.2%) and palatal cortex expansion in 37 cases (55.2%). The nasal floor was invaded in 27 cases (40.3%), the maxillary sinus was invaginated in 26 cases (38.8%), and root resorption was present in 9 cases (13.4%). The average diameter of lesions was (20.89±8.11) mm mesio-distally and (16.70±5.88) mm bucco-palatally. In spite of the 4 residual cysts, the remaining 63 lesions included 14 type Ⅰ, 26 type Ⅱ and 23 type Ⅲ cysts according to the involved tooth number. Besides, the 63 lesions included 46 centripetal, 15 palatal and 2 buccal cysts on sagittal views.@*CONCLUSION@#The maxillary radicular cysts were frequently well-circumscribed round or oval radiolucency, with significantly different sizes. According to the involved tooth number, it can be divided into single tooth, adjacent tooth involvement and multi-teeth types. On sagittal views, the root-cyst relationship was centripetal in most cases, while a minority of cysts expanded palatally or buccally.

Parotid CT imaging reporting and data system: A preliminary study / 北京大学学报(医学版)

OBJECTIVE@#To establish a Parotid Imaging Reporting and Data System (PI-RADS) for CT diagnosis of the parotid gland neoplasms and to investigate the clinical applicable value and feasibility of PI-RADS.@*METHODS@#Patients who had been diagnosed with primary parotid gland neoplasms and had received surgical treatments in Peking University School and Hospital of Stomatology during the period of January 2013 to December 2016 were included in this study. The diagnoses were confirmed by the postoperative pathological examinations in all the patients. The CT imaging data of all patients were retrospectively reviewed and analyzed by two readers in consensus. Imaging characteristics related to the parotid neoplasms were extracted and quantified. Based on comprehensive analysis of the imaging characteristics, the probabilities of the benign and malignant neoplasms were evaluated and classified into six grades, PI-RADS 1-6 (PI-RADS 1: normal parotid gland; PI-RADS 2: confidently benign lesions; PI-RADS 3: probably benign lesions without confirmed evidence of malignancy; PI-RADS 4: suspected malignancy without sufficient evidence of malignancy; PI-RADS 5: confidently malignant lesions; PI-RADS 6: lesions with confirmed pathological evidence of malignancy).@*RESULTS@#A total of 897 patients with 1 003 parotid lesions were included. The lesions included 905 benign and 98 malignant lesions. The proportions of the malignancies in PI-RADS 2, PI-RADS 3, PI-RADS 4 and PI-RADS 5 according to the two readers in consensus were 0.4%, 5.7%, 35.5% and 96.7% respectively. The overall Cohen's Kappa test showed medium consistency between the two independent researchers (κ=0.614, P<0.001, 95%CI: 0.569-0.695). Pearson Chi-square test showed that the proportions of malignancies increased with the diagnostic PI-RADS grades (Cochran-Armitage trend test, Z=-15.579, P<0.001). The results of Pearson Chi-square tests showed significant differences between the grades [PI-RADS 2 and 3 (χ²=12.048, P=0.001); PI-RADS 3 and 4 (χ²=75.231, P<0.001); PI-RADS 4 and 5 (χ²=32.266, P<0.001)].@*CONCLUSION@#PI-RADS can be used to evaluate the risk of malignancy and will be helpful to improve the imaging diagnosis and clinical treatment of parotid gland neoplasms.

Computed tomographic features of desmoplastic ameloblastoma of the jaw / 北京大学学报(医学版)

OBJECTIVE@#To retrospectively analyze the clinical and CT imaging features of desmoplastic ameloblastomas (DA) in comparison with other types of ameloblastomas.@*METHODS@#Patients diagnosed with ameloblastoma histopathologically in Peking University School and Hospital of Stomatology from July 2000 to August 2017 were reviewed to analyze the constituent ratios and characteristics of DA. CT imaging features of DA (28 cases) were investigated in comparison with consecutive cases of solid/multicystic and unicystic ameloblastomas. The following imaging perspectives were analyzed: the border, internal structure, three-dimensional shape, tooth, the periodontium, the cortex and the expansion of the tumors. CT values were measured in the region of interest for quantitative analysis.@*RESULTS@#Among the 1 269 cases of ameloblastomas, 50 (3.9%) were DA, which showed predilections for males (74.0%). The average age of DA was about 43.9 years old, which was higher than the other two types. The anterior incisorcanine region (62.0%) and premolar region (30.0%) were most frequently affected. The incidence rate of DA in mandibule was 56.0% (28/50), which was slightly higher than that of maxilla (44.0%). The DA characteristically showed scallop border and honeycomblike or soapbubble internal structure with bone formation on CT. The mean ratios of height to mesiodistal and buccal-lingual to mesio-distal distances were 0.76 and 0.63, which were higher than the other two types. According to the degree of internal bone formation, three subtypes of DA could be observed: densely ossifying type (I), honeycomb/soap bubble type (II) and sparsely ossifying type (III). The means and standard deviations of CT values of DA were significantly higher than those of the other two types, which were (488.8±164.0) HU (type I), (171.7±102.8) HU (type II), (42.1±8.8) HU (type III).@*CONCLUSION@#CT is helpful for diagnosis of DA, which shows as solid tumor with varying degrees of internal ossification.

Diagnostic accuracy of cone beam computed tomography with different resolution settings for external root resorption / 北京大学学报(医学版)

OBJECTIVE@#To evaluate the diagnostic accuracy of cone beam computed tomography (CBCT) with different resolution settings in detecting the simulated external root resorption defects.@*METHODS@#External root resorption defects were simulated in 51 human single rooted premolar teeth. Cavities simulating root resorption defects of 1 mm in diameter and 0.1 mm, 0.2 mm, and 0.3 mm in depth were drilled in the cervical, middle and apical thirds of lingual surfaces of the teeth. In addition to the 51 locations as controls, a total of 102 cavities were obtained in the present study. Specimens were placed in a human dry mandible and scanned by ProMax 3D and DCT PRO CBCT with different resolution settings, respectively. The three-dimensional CBCT images were evaluated by two experienced observers. The data were analyzed with receiver operating characteristics (ROC) analysis. ROC curves were generated and the area under ROC curve (Az) was employed to express the diagnostic accuracy.@*RESULTS@#The diagnostic accuracy (Az value) of ProMax 3D CBCT with high, normal and low resolution settings were 0.867, 0.703 and 0.665 (P < 0.05), respectively. Defects with depths of 0.2 mm and 0.3 mm were easier to be detected than those with depths of 0.1 mm (P < 0.05). The images obtained by high resolution mode scanning had obvious advantages in detecting smaller defects (depth 0.1 mm and 0.2 mm). The DCT PRO CBCT provided 4 resolution settings including normal quality + normal resolution, normal quality + high resolution, high quality + normal resolution and high quality + high resolution. The Az values for those 4 resolution settings were 0.527, 0.725, 0.743, and 0.794 (P < 0.05), respectively. Similar to ProMax 3D CBCT, the scanning mode with high resolution played a better role in detecting the defects with depth of 0.1 mm. Except for the scanning setting mode with normal quality + normal resolution, the other three modes could well be evaluated for the defects with depth of 0.2 mm and 0.3 mm.@*CONCLUSION@#It is concluded that the diagnostic ability for external root resorption of CBCT could be affected by resolution settings. Computer-aid imaging method can improve the CBCT diagnostic accuracy for external root resorption without increasing the radiation dose level during CBCT scanning.

Clinicopathological characteristics and diagnosis of IgG4related sialadenitis / 北京大学学报(医学版)

Immunoglobulin G4-related sialadenitis (IgG4-RS) is a newly recognized immune-mediated disease and one of immunoglobulin G4-related diseases (IgG4-RD). Our multidisciplinary research group investigated the clinicopathological characteristics and diagnosis of IgG4-RS during the past 10 years. Clinically, it showed multiple bilateral enlargement of major salivary glands (including sublingual and accessory parotid glands) and lacrimal glands. The comorbid diseases of head and neck region including rhinosinusitis, allergic rhinitis, and lymphadenopathy were commonly seen, which could occur more early than enlargement of major salivary glands. Internal organ involvements, such as autoimmune pancreatitis, sclerosing cholangitis, and interstitial pneumonia could also be seen. Thirty-five (38.5%) patients had the symptom of xerostomia. Saliva flow at rest was lower than normal. Secretory function was reduced more severely in the submandibular glands than in the parotid glands. Serum levels of IgG4 were elevated in almost all the cases and the majority of the patients had increased IgE levels. CT, ultrasonography, and sialography showed their imaging characteristics. Histologically it showed marked lymphoplasmacytic inflammation, large irregular lymphoid follicles with expanded germinal centers, prominent cellular interlobular fibrosis, eosinophil infiltration, and obliterative phlebitis. Their immunohistological examination showed marked IgG-positive and IgG4-positive plasma cell infiltration and high IgG4/IgG ratio. The disease could be divided into three stages according to severity of glandular fibrosis. The serum IgG4 level was higher and the saliva secretion lower as glandular fibrosis increased. IgG4-RS should be differentiated from other diseases with enlargement of major salivary gland and lacrimal gland, such as primary Sjögren syndrome, chronic obstructive submandibular sialadenitis, and eosinophilic hyperplastic lymphogranuloma.

Sialoendoscopically-assisted sialolithectomy for the hilar stones of the Wharton's duct / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the clinical effects of sialoendoscopically-assisted sialolithectomy for the sialolithiasis in the hilum of the submandibular glands.</p><p><b>METHODS</b>Between December 2005 and March 2011, treated 80 cases of radiography-verified sialiolithiasis in the hilum of the submandibular glands, The patients included 42 males and 38 females aged from 13 to 68 years. All these patients underwent sialoendoscopic observation and sialoendoscopically-assisted sialolithectomy and were followed up periodically for 3 - 6 months after operation. The success rate of stone removal, postoperative complications and clinical effects were analysed.</p><p><b>RESULTS</b>The stones were completely removed in 71 cases, and almost completely removed in 5 cases, with a successful rate of 95% (76/80). Among 76 successful cases, 8 were treated by basket entrapment, 59 by intraoral open surgery and 9 by both of these two techniques. Within 3 - 6 months' follow-up, 1 case suffered temporary lingual nerve parenthesis and two suffered ranula formation.</p><p><b>CONCLUSIONS</b>Sialoendoscopically-assisted sialolithectomy is a safe and effective gland-preservation technique for the patients with the hilum of the submandibular glands.</p>

Comparative dosimetry of dental cone-beam computed tomography and multi-slice computed tomography for oral and maxillofacial radiology / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To compare the effective radiation dose levels of cone beam computed tomography (CBCT) with those of multi-slice computed tomography (MSCT) when scanning the same maxillofacial regions.</p><p><b>METHODS</b>The effective doses of 2 CBCT (NewTom 9000 and DCT Pro) and 1 MSCT (bright speed edge select 8 slice) scanners were calculated using thermoluminescent dosimeters (TLD) that were placed in a head and neck phantom, and expressed according to the International Commission on Radiation Protection (ICRP) 2007 guidelines.</p><p><b>RESULTS</b>Effective dose values ranged from 41.8 to 249.1 µSv for CBCT. The doses of MSCT scanning for maxilla, mandible and maxilla + mandible were 506.7, 829.9 and 1066.1 µSv, respectively. Dose levels of scanning only for maxilla or mandible were significantly lower than those for maxilla + mandible.</p><p><b>CONCLUSIONS</b>When scanning the same maxillofacial regions, the dose levels for NewTom 9000 and DCT Pro CBCT images were lower than those for Bright speed edge select 8 slice MSCT images. Dose levels reduction could be obtained when smaller regions were scanned.</p>

Endoscopic management of sialolithiasis (a practical experience in 52 cases) / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the value of endoscopy in the diagnosis and treatment of sialolithiasis.</p><p><b>METHODS</b>Diagnostic and interventional sialoendoscopic procedures were performed in 52 patients with sialolithiasis (43 submandibular glands and 9 parotid glands).</p><p><b>RESULTS</b>Of the 34 sialoliths in the anterior and/or posterior part of the Wharton's duct, 24 were removed with basket retrieval; 2 removed with open surgery and basket retrieval, and 8 removed with open surgery under the guidance of endoscopy. Eight sialoliths in the hilum of the Wharton's duct were treated with open surgery. Of the 9 stone cases in the Stensen's duct, 3 was removed with basket retrieval, 3 was removed after opening-up of the ostium, 1 was treated with basket capturing and open surgery. The obstructive symptoms were improved in these cases during 1-24 months' follow-up.</p><p><b>CONCLUSIONS</b>Sialoendoscopy is a minimal invasive and efficacious technique for the diagnosis and treatment of sialolithiasis.</p>

A study of trabecular bone structure in the mandibular condyle of healthy young people by cone beam computed tomography / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the feasibility of cone beam computed tomography (CBCT) for the evaluation of trabecular bone structure in mandibular condyle and to investigate the distribution of the trabecular bone structure within mandibular condyle.</p><p><b>METHODS</b>Eighty condyles from 40 healthy young volunteers (aged 20-32) were scanned by CBCT. A coronoid image was acquired of each condyle and divided into 8 regions where regions of interest were specified. After CBCT images were binarized, four morphological parameters including bone volume fraction, trabecular thickness, trabecular number and trabecular separation were computed.</p><p><b>RESULTS</b>All parameters were significantly different between the superior zone and middle/inferior zone of the condyle (P < 0.05). Superior zone showed the largest bone volume fraction (52.2%), the highest trabecular number (1.33 mm(-1)), the thinnest trabecular thickness (393.48 microm), and the smallest trabecular separation (361.59 microm). Inferior zone showed the smallest bone volume fraction (49.64%). These results were not significantly different between bilateral sides of the condyles (P > 0.05).</p><p><b>CONCLUSIONS</b>Trabecular bone structure was inhomogeneous within the condyle, but symmetrical between bilateral sides of the condyles. CBCT combined with image processing is a feasible tool in evaluating trabecular bone structure of human mandibular condyle.</p>