Comparison of prognosis in two methods for the lingual nerve repair: direct suture with vein graft cuff and collagen allograft method / 대한악안면성형재건외과학회지

Background@#No studies have compared the outcomes of direct perineurial suture with vein graft cuff repair and indirect collagen allograft repair of the lingual nerve following an injury. Therefore, we evaluated and compared the outcomes of each over a 1-year observation period. We retrospectively assessed 20 patients who had undergone microneurosurgical repair of unilateral lingual nerve injuries at the Wakayama Medical University Hospital between May 2015 and March 2019. We utilized two different methods for lingual nerve repair, i.e., direct perineurial repair with a vein graft cuff and interpositional collagen allograft repair. Sensory and taste function in the lingual nerve were preoperatively evaluated using a static two-point discrimination test, superficial pain/tactile sensation test, tests for the pressure pain threshold (Semmens-Weinstein monofilament), test for thermal discrimination hot and cold sensation, and a taste discrimination test. These tests were performed again at 6 and 12 months postoperatively. @*Results@#Compared to the preoperative conditions, all patients showed improved sensory reactions. Functional sensory recovery outcomes were defined by Pogrel’s criteria, Medical Research Council Scale grades, and functional sensory recovery. In each group, all patients improved after the operation. However, the operation time was significantly shorter for an interpositional collagen allograft repair as compared to that for a direct perineurial repair with a vein graft cuff. @*Conclusions@#There were no statistically significant differences between the two repair Methods, except for the operation time. Both methods led to satisfactory results for all criteria. From an economic point of view, direct perineurial repair with a vein graft cuff is meaningful; however, the esthetic effect on the donor site should be considered. Conversely, interpositional collagen allograft repair has the advantage of a greatly shortened operation time.

Risk of lingual nerve injuries in removal of mandibular third molars: a retrospective case-control study / 대한악안면성형재건외과학회지

BACKGROUND@#Through the analysis of clinical data, we attempted to investigate the etiology and determine the risk of severe iatrogenic lingual nerve injuries in the removal of the mandibular third molar.@*METHODS@#A retrospective chart review was performed for patients who had undergone microsurgical repair of lingual nerve injuries. The following data were collected and analyzed: patient sex, age, nerve injury side, type of impaction (Winter's classification, Pell and Gregory's classification). Ratios for the respective lingual nerve injury group data were compared with the ratios of the respective data for the control group, which consisted of data collected from the literature. The data for the control group included previous patients that encountered various complications during the removal of the mandibular third molar.@*RESULTS@#The lingual nerve injury group consisted of 24 males and 58 females. The rate of female patients with iatrogenic lingual nerve injuries was significantly higher than the control groups. Ages ranged from 15 to 67 years, with a mean age of 36.5 years old. Lingual nerve injury was significantly higher in the patient versus the control groups in age. The lingual nerve injury was on the right side in 46 and on the left side in 36 patients. There was no significant difference for the injury side. The distoangular and horizontal ratios were the highest in our lingual nerve injury group. The distoangular impaction rate in our lingual nerve injury group was significantly higher than the rate for the control groups.@*CONCLUSION@#Distoangular impaction of the mandibular third molar in female patients in their 30s, 40s, and 50s may be a higher risk factor of severe lingual nerve injury in the removal of mandibular third molars.

PD-L1 expression correlated with p53 expression in oral squamous cell carcinoma / 대한악안면성형재건외과학회지

BACKGROUND@#Programmed cell death ligand 1 (PD-L1) is an immune checkpoint molecule that attenuates the immune response. PD-L1 contributes to failed antitumor immunity; thereby, blockade of PD-L1 with monoclonal antibody enhances the immune response. Recently, it was reported that PD-L1 was regulated by protein 53 (p53). Besides, cytokeratin 17 (CK17) is thought to be a diagnostic marker of oral squamous cell carcinoma (OSCC). Our aim was to evaluate the correlation between the immunohistochemical expression of PD-L1, p53 and CK17 with clinicopathological characteristics and disease-specific survival in patients with OSCC.@*METHODS@#A total of 48 patients with OSCC were included in this study. Immunohistochemical staining was performed to evaluate the correlation among the expressions of PD-L1, p53 and CK17, and furthermore the correlation among various clinicopathological factors, PD-L1, p53 and CK17.@*RESULTS@#The positive rate of p53, CK17, PD-L1 (tumor cells) and PD-L1 (tumor-infiltrating lymphocytes) was 63.2%, 91.7%, 48.9% and 57.1%. A statistically significant correlation between p53 expression and T stage and TNM stage (p = 0.049, p = 0.03, respectively) was observed. Also, a statistically significant correlation between p53 and PD-L1 (TCs) expression (p = 0.0009) was observed. Five-year disease-specific survival rate was not significantly correlated with gender, TNM stage, p53 expression, PD-L1 expression and CK17 expression.@*CONCLUSION@#The expression of p53 and PD-L1 shows significantly positive correlation in oral squamous cell carcinoma in tumor cells. Also, a significant correlation between p53 expression and T stage and TNM stage was observed. No other significant correlation between PD-L1 staining or CK17 and clinical or pathologic characteristics was identified.

A case report of a long-term abandoned torn lingual nerve injury repaired by collagen nerve graft induced by lower third molar extraction / 대한악안면성형재건외과학회지

BACKGROUND@#The lingual nerve plays an important role in multiple functions, including gustatory sensation and contact sensitivity and thermosensitivity. Misdiagnosed conservative treatments for serious lingual nerve (LN) injuries can induce the patient to serious mental disability. After continuous observation and critical diagnosis of the injury, in cases involving significant disruption of lingual nerve function, microneurosurgical reconstruction of the nerve is recommended. Direct anastomosis of the torn nerve ends without tension is the recommended approach. However, in cases that present significant gaps between the injured nerve ends, nerve grafts or conduits (tubes of various materials) are employed. Recently, various reconstruction materials for peripheral nerves were commercially offered especially in the USA, but the best method and material is still unclear in the world. There currently exists no conventional protocol for managing LN neurosensory deficiency in regard to optimal methods and the timing for surgical repair. In Japan, the allograft collagen nerve for peripheral nerves reconstruction was permitted in 2017, and we tried to use this allograft nerve and got a recommendable result.CASE PRESENTATION: This report is a long-term abandoned torn LN reconstructed with allograft nerve induced by the lower third molar extraction.@*CONCLUSIONS@#In early sick period, with the exact diagnosis, the LN disturbance should be managed. In a serious condition, the reconstruction with allograft nerve is one of the recommendable methods.

Effect of duration from lingual nerve injury to undergoing microneurosurgery on improving sensory and taste functions: retrospective study / 대한악안면성형재건외과학회지

BACKGROUND@#The prognosis of recovery following microneurosurgery for injured lingual nerves varies among individual cases. This study aimed to investigate if recovery ratios of sensory and taste functions are improved by the microneurosurgery within 6 months after lingual nerve injury.@*METHODS@#We retrospectively assessed 70 patients who underwent microneurosurgery at the Wakayama Medical University Hospital for lingual nerve injuries between July 2004 and December 2016. Sensory and taste functions in lingual nerves were preoperatively evaluated using a static two-point discrimination test, an intact superficial pain/tactile sensation test, and a taste discrimination test. They were evaluated again at 12 and at 24 months postoperatively. The abundance ratio of Schwann cells in the excised traumatic neuromas was analyzed with ImageJ software following immunohistochemistry with anti S-100β antibody.@*RESULTS@#In early cases (microneurosurgery within 6 months after the injury), recovery ratios of sensory and taste functions were not significantly different at 24 months after microneurosurgery compared with later cases (microneurosurgery more than 6 months after the injury). Meanwhile, the ratio of patients with taste recovery within 12 months after microneurosurgery was significantly decreased in late cases compared with early cases. The abundance ratio of Schwann cells in traumatic neuroma was also significantly lower in later cases.@*CONCLUSION@#Microneurosurgery more than 6 months after lingual nerve injury did not lead to decreased recovery ratio of sensory and taste functions, but it did lead to prolonged recovery of taste. This delay may be associated with a decrease in the abundance ratio of Schwann cells in traumatic neuromas.

Epidemiological Study of Malignant Tumors in the Oral and Maxillofacial Region - Survey of Member Institutions of the Japanese Society of Oral and Maxillofacial Surgeons, 2002

We studied 1809 oral cancer patients who visited and were treated in 2002 at the 148 institutions certified as training facilities by the Japanese Society of Oral and Maxillofacial Surgeons, which is composed of 39 dental university hospitals, 44 medical university hospitals, 64 general hospitals, and 1 unknown institution. The patients consisted of 1071 (59.2 %) males and 738 (40.8 %) females (male:female ratio, 1.45:1), who had a mean age of 65.2 years old. The tongue (40.2 %) was the most common site affected, followed by the gingiva (32.7 %), buccal mucosa (10.1 %), and oral floor (9.0 %). There were 6 cases of intraoral multiple cancer. In histopathological examinations, squamous cell carcinoma (88.7 %) was the most common type found, followed by adenoid cystic carcinoma (2.1 %), and mucoepidermoid carcinoma (1.7 %). In addition, non-epithelial tumors comprised 1.8 % , among which malignant melanoma was the most common type. Cases classified as T2N0 were the most common (32.1 %), followed by T1N0 (21.4 %), T4N0 (8.0 %), and T2N1 (7.6 %). Distant metastasis occurred in 17 patients (1.0 %). The sizes of the non-epithelial malignant tumors ranged from 1.0 to 7.0 cm, with a mean size of 3.7 cm.

Epidemiological Study of Malignant Tumors in the Oral and Maxillofacial Region - Survey of Member Institutions of the Japanese Society of Oral and Maxillofacial Surgeons, 2002

We studied 1809 oral cancer patients who visited and were treated in 2002 at the 148 institutions certified as training facilities by the Japanese Society of Oral and Maxillofacial Surgeons, which is composed of 39 dental university hospitals, 44 medical university hospitals, 64 general hospitals, and 1 unknown institution. The patients consisted of 1071 (59.2 %) males and 738 (40.8 %) females (male:female ratio, 1.45:1), who had a mean age of 65.2 years old. The tongue (40.2 %) was the most common site affected, followed by the gingiva (32.7 %), buccal mucosa (10.1 %), and oral floor (9.0 %). There were 6 cases of intraoral multiple cancer. In histopathological examinations, squamous cell carcinoma (88.7 %) was the most common type found, followed by adenoid cystic carcinoma (2.1 %), and mucoepidermoid carcinoma (1.7 %). In addition, non-epithelial tumors comprised 1.8 % , among which malignant melanoma was the most common type. Cases classified as T2N0 were the most common (32.1 %), followed by T1N0 (21.4 %), T4N0 (8.0 %), and T2N1 (7.6 %). Distant metastasis occurred in 17 patients (1.0 %). The sizes of the non-epithelial malignant tumors ranged from 1.0 to 7.0 cm, with a mean size of 3.7 cm.