Oral microbial dysbiosis in patients with oral cavity cancers.

OBJECTIVES: The pathogenesis of oral cavity cancers is complex. We tested the hypothesis that oral microbiota dysbiosis is associated with oral cavity cancer. MATERIALS AND METHODS: Patients with primary oral cavity cancer who met the inclusion and exclusion criteria were included in the study. Matching healthy individuals were recruited as controls. Data on socio-demographic and behavioral factors, self-reported periodontal measures and habits, and current dental status were collected using a structured questionnaire and periodontal chartings. In addition to self-reported oral health measures, each participant received a standard and detailed clinical examination. DNA was extracted from saliva samples from patients and healthy controls. Next-generation sequencing was performed by targeting V3-V4 gene regions of the 16 S rRNA with subsequent bioinformatic analyses. RESULTS: Patients with oral cavity cancers had a lower quality of oral health than healthy controls. Proteobacteria, Aggregatibacter, Haemophilus, and Neisseria decreased, while Firmicutes, Bacteroidetes, Actinobacteria, Lactobacillus, Gemella, and Fusobacteria increased in oral cancer patients. At the species level, C. durum, L. umeaens, N. subflava, A. massiliensis, and V. dispar were significantly lower, while G. haemolysans was significantly increased (p < 0.05). Major periodontopathogens associated with periodontal disease (P. gingivalis and F.nucleatum) increased 6.5- and 2.8-fold, respectively. CONCLUSION: These data suggested that patients with oral cancer had worse oral health conditions and a distinct oral microbiome composition that is affected by personal daily habits and may be associated with the pathogenicity of the disease and interspecies interactions. CLINICAL RELEVANCE: This paper demonstrates the link between oral bacteria and oral cancers, identifying mechanistic interactions between species of oral microbiome.

Repeated Atmospheric Pressure Alteration Effect on the Cochlea in Rats: Experimental Animal Study.

OBJECTIVE: This study aimed to evaluate the effects of repeated pressure alterations on cochlear structures in rats in an attempt to understand indirectly the inner ear status of flight crew who are repeatedly exposed to pressure alterations.METHODS: There were 12 adult Wistar albino rats equally divided into 2 groups: Group 1 (controls) and Group 2 (study group). The animals in Group 2 were exposed to repeated pressure changes in a pressure cabin which is regulated by manometers. The animals in Group 1 were placed in the cabin without being exposed to pressure changes. Auditory brainstem response (ABR) testing was performed in all animals at the beginning and at the end of the study. After 12 wk the animals were sacrificed and their cochleas were investigated using scanning electron microscopy (SEM).RESULTS: In the study group, hearing decreases at 2 kHz, 4 kHz, 6 dB at 8 kHz, and 32 kHz were encountered at the end of 3 mo. On SEM evaluation of the control group, the outer hair cells (OHC) and stereocilia were normal throughout the cochlea. In the study group, there were irregularities in lateral surface connections and separations, collapse, and adhesions in the basal segment of the cochlea and partial loss of stereocilia throughout the cochlea.CONCLUSION: Repeated alterations in the atmospheric pressure can lead to damage in the inner ear with subtle or evident hearing loss. Frequent flyers like air workers may be at risk of inner ear damage, which may be considered an occupational health problem.Eroglu S, Dizdar HT, Cevizci R, Cengiz AB, Ogreden S, Bulut E, Ilgezdi S, Dilci A, Ustun S, Sirvanci S, Kaya OT, Bayazit D, Caki BO, Oktay MF, Bayazit Y. Repeated atmospheric pressure alteration effect on the cochlea in rats: experimental animal study. Aerosp Med Hum Perform. 2021; 92(7):550555.

Association of Conductive Hearing Loss with the Structural Changes in the Organ of Corti.

OBJECTIVE: The aim of the study was to evaluate the association of conductive hearing loss (CHL) with the structural changes in the organ of Corti. METHODS: Twenty ears of 10 healthy adult Wistar albino rats were included in the study. The right ears (n = 10) of the animals served as controls (group 1), and no surgical intervention was performed in these ears. A tympanic membrane perforation without annulus removal was performed under operative microscope on the left ears (n = 5) in 5 of 10 animals (group 2). A tympanic membrane perforation with annulus removal was performed under operative microscope on the left ears (n = 5) of the remaining 5 animals (group 3). Auditory brainstem response testing was performed in the animals before the interventions. After 3 months, the animals were sacrificed, their temporal bones were removed, and inner ears were investigated using scanning electron microscopy (SEM). The organ of Corti was evaluated from the cochlear base to apex in the modiolar axis, and the parameters were scored semiquantitatively. RESULTS: In group 1, the pre- and post-intervention hearing thresholds were similar (p > 0.05). In group 2, a hearing decrease of at least 5 dB was encountered in all test frequencies (p > 0.05). In group 3, at the frequency range of 2-32 kHz, there was a significant hearing loss after 3 months (p < 0.01). After 3 months, the hearing thresholds in group 2 and 3 were higher than group 1 (p < 0.01). The hearing threshold in group 3 was higher than group 2 (p < 0.01). On SEM evaluation, the general cell morphology and stereocilia of the outer hair cells were preserved in all segments of the cochlea in group 1 with a mean SEM score of 0.2. There was segmental degeneration in the general cell morphology and outer hair cells in group 2 with a mean SEM score of 2.2. There was widespread degeneration in the general cell morphology and outer hair cells in group 3 with a mean SEM score of 3.2. The SEM scores of group 2 and 3 were significantly higher than group 1 (p < 0.05). The SEM scores of group 3 were significantly higher than group 2 (p < 0.05). CONCLUSION: CHL may be associated with an inner ear damage. The severity of damage appears to be associated with severity and duration of CHL. Early correction of CHL is advocated in order to reverse or prevent progression of the inner ear damage, which will enhance the success rates of hearing restoration surgeries. Subjective differences and compliance of the hearing aid users may be due to the impact of CHL on inner ear structures.

Dorsal Augmentation of Saddle Nose Deformity With Toothpick-Shaped Costal Cartilage Grafts in the Secondary Septorhinoplasty.

Saddle nose deformity is a challenging complication of septoplasty or septorhinoplasty, characterized by underprojected cartilaginous dorsum. Nasal dorsal augmentation is a significant part of reconstructive surgery of saddle nose deformities. In this study, the authors aimed to discuss the results of using toothpick-shaped costal cartilage grafts in nasal dorsal augmentation of saddle nose deformity. Twelve patients who underwent nasal dorsal augmentation due to moderate to severe saddle nose deformity secondary to the previous septoplasty or septorhinoplasty were retrospectively reviewed. Costal cartilage grafts prepared in the shape of toothpicks were used in all patients. Costal cartilage was used as toothpick-shaped free grafts in 12 patients (female: 7, male: 5) with a mean age of 42 (range: 24-56) for dorsal augmentation in the secondary septorhinoplasty. All patients had a history of previous surgery (septoplasty, n = 9; and septorhinoplasty, n = 3). All patients were operated under general anesthesia with open technique septorhinoplasty. The mean follow-up was 18 (range: 9-48) months. In only 1 of the 12 patients, a postoperative complication was observed including an infection of the tip area in the second postoperative week. None of the patients experienced donor site complications or major graft resorption. All patients were satisfied with functional and esthetic outcomes. No revision surgery was needed in any patient. Toothpick-shaped costal cartilage grafts are useful in nasal dorsal augmentation of moderate to severe saddle nose deformity. This technique offers smooth camouflage, satisfactory accordance with the recipient region, and shorter operation time. In addition, it avoids the side effects from wrapping techniques such as foreign body reaction or additional donor site morbidities.

Efficacy of sublingual immunotherapy for house dust mite allergic rhinitis.

In the present study, we investigated the outcomes of sublingual immunotherapy (SLIT) in house dust mite-induced allergic rhinitis (HDM-AR) patients. In this prospective, multicentric study, 186 patients with AR who had positive skin prick test results for HDMs were included. The patients were administered SLIT using Staloral 300 for 1 year. Evaluation of the patients regarding symptom scores, clinical findings and Rhinitis Quality of Life Questionnaire (RQLQ) scores was performed at baseline, and then at 6 and 12 months of therapy. Our results showed that, for all of the evaluated items (symptom scores, clinical findings and RQLQ scores), 12-month values were significantly lower than those at 6 months and baseline. Similarly, 6-month values were significantly lower than those at baseline. There were no complications in any of our patients. SLIT for HDM-AR is a treatment modality that can be used safely. We obtained better results than expected, and the treatment showed a positive psychological effect; the patients believed that SLIT was the final step of treatment and, which made them feel better.

Epidemiology and economic burden of nonmelanoma skin cancer.

The authors present a succinct summary of the incidence and costs of nonmelanoma skin cancers. They present incidence and health care costs for this disease from Australia, United States, and Europe, noting that NMSC care cost stands in fifth place after prostate, lung, colon, and breast carcinomas.

Bipolar radiofrequency-induced interstitial thermoablation for oral cavity vascular malformations: Preliminary results in a series of 5 children.

We report our assessment of the effectiveness of bipolar radiofrequency-induced interstitial thermoablation (BRIT) for the treatment of certain oral cavity vascular malformations in 5 children. Two of these patients had lymphangiomatous macroglossia (LM), 1 had lymphangioma circumscriptum (LC), and 2 had a venous malformation (VM). Each patient underwent BRIT at least twice; treatment was delivered at 4- to 8-week intervals according to each patient's circumstances. The 2 patients with LM required three treatment sessions; although their tongue volume decreased after each session, both still required a partial glossectomy to achieve a satisfactory reduction in volume. The patient with LC underwent two BRIT treatments, which reduced the size of the lesion by half; the remainder was excised. The 2 patients with a VM (1 buccal and 1 lingual) responded well to BRIT, and their malformations almost completely disappeared. Our early results with BRIT suggest that it is an effective treatment for oral cavity vascular malformations-more so for patients with venous rather than lymphangiomatous lesions.

The Score For Allergic Rhinitis study in Turkey.

BACKGROUND: The clinical definition of allergic rhinitis (AR) is difficult to use in epidemiological settings of large populations where it is impossible to obtain the laboratory evidence of each immune response. However, the standardization of the definition of AR in epidemiological studies is of crucial importance. This study was designed to estimate the prevalence of AR in an adult general population with respect to seven distinct geographical regions in Turkey. METHODS: Individuals were evaluated with the Score for Allergic Rhinitis (SFAR) questionnaire for a national cross-sectional study. The Turkish version of the SFAR questionnaire was tested for clarity and sensitivity in a small sample of the general population. RESULTS: Among the 3967 interviewed subjects, the overall prevalence of AR was 29.6%, with regional variations (from 21.0% in the southeastern Anatolia region to 36.1% in the Marmara region). The prevalence was higher in women and in urban area of residence. CONCLUSION: This national survey confirmed the elevated prevalence of AR in Turkey. Our findings may contribute to the formulation of the public health policy and development of preventive and therapeutic strategies for AR in eastern Europe.

Comparison of radiofrequency applied to the total inferior choncha with application to its anterior third.

OBJECTIVE: To compare radiofrequency application to the anterior 1/3 of the inferior choncha with application to the whole of the inferior choncha. MATERIAL AND METHOD: 40 patients with nasal obstruction due to isolated inferior choncha hypertrophy were evaluated. RF was applied in the first group only to the anterior 1/3 of the choncha, whereas in the second group the whole choncha was ablated. Anterior rhinomanometry measurements were obtained both before and 6 weeks after surgery along with visual analog scales. Complete data was used to compare the efficacy of both techniques. RESULTS: The combined nasal resistance showed a significant decrease in both groups. VAS scores were also substantial for both groups. Both groups showed similar data proving the two techniques to have similar efficacy. CONCLUSION: Application to the anterior 1/3 compared with application to the whole of the choncha show no significant differences. Simple RF application here not only provides adequate control but also is safer as there is less risk of interruption of continuity of the nasal mucosa.

Efficacy of Tonimer gel spray on postoperative nasal care after endonasal surgery.

OBJECTIVE: To investigate the effect of the addition of Tonimer gel spray into nasal mucosa care on nasal mucosal findings and patient comfort in the postoperative period of endonasal surgery. MATERIAL AND METHOD: 40 patients who underwent endonasal surgery were included in the study. For the postoperative nasal care, isotonic saline was applied to both nasal cavities, and subsequently, Tonimer nasal gel spray was additionally applied to the right nasal cavity. Patients were examined on the 2nd, 7th, and 15th postoperative days. The findings of the examinations were scored with respect to crusting and the patient nasal comfort was assessed using the visual analog scale (VAS). RESULTS: The VAS values which measure patient comfort and crusting were significantly lower on the Tonimer side compared to control (p < 0.01). CONCLUSION: Tonimer and saline combination was found to be superior to saline per se in decreasing crusting and improving patient nasal comfort in the postoperative period.

Reliable surgical landmarks for the identification of the recurrent laryngeal nerve.

OBJECTIVE: To obtain reliable landmarks for identification of the recurrent laryngeal nerve in human larynges. STUDY DESIGN AND SETTING: This is a prospective study, analyzing the laryngeal anatomic features. Structures easily palpable on the thyroid and cricoid cartilage (ie, the most prominent portion of the inferior cornu of the thyroid cartilage [IC], the inferior tubercle of the thyroid cartilage [ITT] and the most anterior portion of the arch of the cricoid cartilage [AC]) were accepted as landmarks and the distances of these structures to the entrance point of the RLN on the medial aspect of the inferior pharyngeal constrictor muscle (cross point [CP]) were measured in 65 adult autopsies. RESULTS: When a straight line is drawn 11 to 12 millimeters (mm) from the IC, 22 to 24 mm from the ITT, and 26 to 28 mm from the AC, the point at which they intersect indicates the point at which the RLN enters the medial side of the inferior pharyngeal constrictor muscle (ICM) and is easy to locate at this point. All of the RLN were seen to lie posterolateral to the Berry ligament. Thirty-eight of 65 cases possessed extralaryngeal bifurcation of the RLN. CONCLUSION: With such constant mathematic values, these 3 landmarks are reliable markers for identification of RLN. This study is important in the fact that it states constant mathematic values regarding surgical landmarks used to expose the RLN.

The role of gastric Helicobacter pylori infection in laryngopharyngeal reflux disease.

OBJECTIVES: To investigate the role of Helicobacter pylori (H pylori) infection in laryngopharyngeal reflux (LPR). STUDY DESIGN: A prospective multidisciplinary clinical study. METHODS: Forty-four adult patients who applied to our ENT clinic with LPR symptoms were evaluated. Then these patients underwent upper gastrointestinal system endoscopy and double probe pH monitoring. In addition, during the endoscopy multiple biopsies from the stomach were obtained to detect H pylori. RESULTS: Results from 32 LPR positive patients were assessed (10 male and 22 female). There were no statistically significant differences between the presence of H pylori and sex, age, degree of gastritis and esophagitis, and also the number of reflux, fractional acid exposure time regarding proximal probe readings. Similarly for both proximal and distal probe readings, the average score of esophageal acid clearance was not statistically significant (P > 0.05). In addition, no statistically significant difference was found between the presence of H pylori and GERD (P > 0.05). CONCLUSIONS: The results of this study demonstrated that there is no relationship between gastric H pylori infection and LPR. EBM RATING: B-3b.

Negative effect of immediate hyperbaric oxygen therapy in acute acoustic trauma.

OBJECTIVE: The functional evaluation of the effect of the hyperbaric oxygen therapy (HBOT) onset time on cochlea by using distortion product otoacoustic emission. STUDY DESIGN: Animal study. METHODS: Twenty-four Wistar albino rats were divided into six groups and their right ears were directly exposed to a 110-dB sound pressure level (1-12 kHz) white noise for 25 minutes. The first group was considered the control group. HBOT was started at 1 hour postexposure for the second group, at 2 hours postexposure for the third group, at 6 hours postexposure for the fourth group, at 24 hours postexposure for the fifth group, and at 48 hours postexposure for the sixth group. Signal-to-noise ratios (SNRs) were recorded before the noise exposure; immediately after the noise exposure; and on the 3rd, 7th, and 10th day of postexposure. RESULTS: SNRs at 6 to 8 kHz were significantly decreased after the acoustic trauma. The evaluation on the third day of postexposure showed that recovery begun in all groups except the group in which the HBOT was started at 1 hour postexposure. SNRs in the control group and HBOT groups were back to the preexposure levels at 10 days postexposure, except the 1- and 2-hour postexposure groups. However, in the group in which the HBOT was started at 1 hour postexposure, distortion product otoacoustic emissions were lost except at 4 kHz. The recovery of the SNRs in hyperbaric oxygen administration at 2 hours postexposure almost completed on the 10th day after noise exposure. CONCLUSION: Immediate HBOT in acoustic trauma treatment is not necessary; on the contrary, it has an adverse effect.

Relationship between the superior attachment type of uncinate process and presence of agger nasi cell: a computer-assisted anatomic study.

OBJECTIVE: The uncinate process (UP) is an important anatomic landmark in frontal recess surgery. Its superior attachment shows great anatomic variability. The agger nasi (AN) cell is another important structure that affects frontal recess anatomy and there is a close neighborhood between them. The aim of this study was to investigate the relationship between superior attachment type of UP and the presence of AN cell. STUDY DESIGN: A retrospective anatomical study. METHOD: Computed tomography scans were evaluated of 486 sides of 243 patients who had had paranasal sinus. In 125 (26%) sides, the superior attachment of the UP could not be identified. In the remaining 361 (74%) sides, the prevalence of superior attachment of UP types and the presence of AN cell in each side were recorded. The results were evaluated with chi2 test. RESULTS: The AN cell was found in 290 (80.3%) of 361 sides. The prevalence of AN cell according to superior attachment of UP types were 79.6% for type 1/2, 90.1% for type 3, 71.4% for type 4, 86.5% for type 5, and 83.3% for type 6. The presence of AN cell according to superior attachment types of UP was not statistically significant (chi2= 3.54, P = 0.315). CONCLUSIONS: The AN cell was found to be present in 80.3% of the cases. However, the relationship between the presence of the AN cell and the superior attachment types of UP was not statistically significant.

Effects of topical application of methotrexate on nasal mucosa in rats: a preclinical assessment study.

OBJECTIVE: The aim of this study is to investigate dose-dependent effect of the topical application of methotrexate (MTX) in rats on the normal nasal mucosa, liver tissue, liver enzymes, and hemoglobin levels. STUDY DESIGN: Preclinical animal study. SETTING: Twenty male adult wistar albino rats were randomly divided into 4 groups (n=5). A single puff of MTX (2.5 microg) was applied to both nasal cavities 2 times a day. The animals were given MTX 1 day a week in group 1, 3 days a week in group 2, and 5 days a week in group 3. Control group animals were given 1 puff of physiologic saline to both nasal cavities 5 days a week and 2 times a day. After 28 days, liver biopsies, blood samples, and 5 nasal mucosal biopsies were taken. Histological examination was made with respect to certain parameters semiquantitatively (grade 0-3). The aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels and hemoglobin counts were studied from blood samples. RESULTS: There are no statistically significant differences with respect to histopathological parameters between the control group and the groups 1-3 (P>0.05). Histopathological examination of liver tissue did not reveal any evident difference between the control and study groups. Mean AST and ALT as liver function tests and hemoglobin counts were within normal limits. Topical application of MTX at these doses has no toxic effect on the nasal mucosa, the liver tissue, AST and ALT levels, and hemoglobin level. CONCLUSIONS: These results have been encouraging to investigate use of the topical application of MTX in nasal manifestation of autoimmune disease or addition of the topical application of MTX to the steroid treatment in cases with massive nasal polyposis resistant to steroids and prone to recurrence.

What is the true incidence of horizontal semicircular canal benign paroxysmal positional vertigo?

OBJECTIVE: To assess the correct incidence of horizontal semicircular canal (H-SCC) benign paroxysmal positional vertigo (BPPV). STUDY DESIGN: Retrospective assessment of patients with BPPV. METHODS: All patients with BPPV were included and the rates of involvement of posterior, horizontal, and anterior SCCs were determined. RESULTS: One hundred sixty-nine patients with the diagnosis of BPPV were evaluated. One hundred forty-four patients (85.2%) were found to have posterior SCC (P-SCC) involvement, and there were 20 patients (11.8%) with horizontal SCC (H-SCC) and 2 patients (1.2%) with anterior SCC (A-SCC) involvement. Three patients (1.8%) had simultaneous H-SCC and P-SCC BPPV ipsilaterally. Geotropic nystagmus was seen in 17 out of 23 patients (73.9%) in roll test, and ageotropic nystagmus was seen in the remaining 6 patients (26.1%). CONCLUSION: H-SCC constitutes 13.6% of all BPPV cases. H-SCC BPPV with geotropic nystagmus is more common. H-SCC BPPV can coexist with ipsilateral P-SCC BPPV. However, in some cases of H-SCC BPPV, Dix-Hallpike maneuver can cause vertigo and horizontal nystagmus. This may be confused with P-SCC BPPV. Therefore, the roll test must be performed in all cases in addition to Dix-Hallpike maneuver and both ears must be evaluated with respect to all SCCs for BPPV. EBM RATING: C-4.

Rhinocerebral mucormycosis: a report of two cases.

Rhinocerebral mucormycosis is an aggressive fungal disease that involves the nose, paranasal sinuses, orbit and central nervous system. It may rapidly be fatal. This infection usually occurs secondary to immune suppression, diabetic ketoacidosis, and prolonged use of antibiotics, steroids, and cytotoxic drugs. Management of the condition consists of treatment of the underlying disease and surgical debridement combined with intravenous amphotericin B. This paper presents two patients with rhinocerebral mucormycosis, both suffering from diabetes. Complete recovery was achieved in one patient with surgical debridement of necrotic tissue combined with systemic antifungal treatment, whereas in the other, the disease was complicated with subarachnoid hemorrhage and the patient died on the third day of treatment.

[The effect of bicanalicular silicone tube implantation on the success rate of endoscopic dacryocystorhinostomy]. / Endoskopik dakriosistorinostomide bikanaliküler silikon tüp implantasyonunun ameliyat basarisi üzerine etkisi.

OBJECTIVES: We evaluated operative success rates of endoscopic dacryocystorhinostomy with or without bicanalicular silicone tube implantation. PATIENTS AND METHODS: Twenty-six eyes of 24 patients with simple epiphora (23 eyes) or chronic dacryocystitis (3 eyes) were treated by endoscopic dacryocystorhinostomy with (18 eyes) or without (8 eyes) bicanalicular silicone tube implantation. In the implantation group, one patient underwent endoscopic sinus surgery and two patients underwent submucosal resection. The silicone tubes were removed after a mean of 4.48 months (range 7 days to 6 months). The mean follow-up period was 12.4 months. RESULTS: During the follow-up period, no significant differences were found between the two treatment groups with respect to the occurrence of epiphora. It disappeared in 17 eyes (94.5%) and in six eyes (75%) with or without silicone tube implantation, respectively. Operative success rates were significantly different between patients with simple epiphora (95.7%) and chronic dacryocystitis (33.3%). The only complication was a punctual damage seen in one patient. CONCLUSION: The lack of a significantly high influence on the success rate, increased operative cost, and the risk for complications due to silicone tube insertions may be considered disadvantages of bicanalicular silicone tube implantation.

[Grand mal seizure following intrathecal fluorescein use]. / Intratekal fluoresein kullanimi takiben gelisen epilepsi nöbeti.

In a 43-year-old woman, 1 ml of 5% fluorescein diluted with 10 ml of cerebrospinal fluid (CSF) was injected into the subarachnoid space at the L4-L5 level to evaluate nasal CSF leakage. After the injection, amnesia and grand mal seizure developed following a low-back pain spreading through the right leg. The patient was treated with antiedematous and anticonvulsant drugs. CSF drainage and vigorous hydration were performed. The patient recovered without sequelae. It was concluded that intrathecal fluorescein should be used with caution.

[The topographical anatomy of the external branch of the superior laryngeal nerve and its importance in thyroid surgery: a cadaver study]. / Süperior larenjeal sinirin eksternal dalinin topografik anatomisi ve tiroit cerrahisindeki önemi: Kadavra çalismasi.

OBJECTIVES: We investigated topographical anatomic features of the external branch of the superior laryngeal nerve (SLN) in relation to the superior thyroid artery (STA) and its vulnerability to injury in individuals with a normal thyroid size. STUDY DESIGN: Thirty fresh cadavers (18 females, 12 males; age range 20 to 50 years) with a normal thyroid size and no signs of abnormality in the neck were studied. The external branch of the SLN was identified and classified according to the system proposed by Cernea et al. RESULTS: The topographical relationship between the external branch of the SLN, the STA, and the upper pole of the thyroid gland was identified in 54 thyroid lobes (90%). Identification was not possible in six lobes because of bleeding or injury. The location of the external branch of the SLN was consistent with type 1 in 28 lobes (51.8%) and type 2 in 26 lobes (48.2%; type 2a in 37.1% and type 2b in 11.1%). No significant relationships existed between the type of the nerve, gender, and age, nor was there any symmetry with regard to the location of the external branch of the SLN in the same subject. CONCLUSION: Nearly half of the Turkish population with a normal thyroid gland size present high surgical risks during thyroid surgery because of the course of the external branch of the SLN.