The effect of subperichondrial dissection on nasal vascularity in septorhinoplasty operations.

PURPOSE: Nasal vascularization runs above the superficial musculoaponeurotic system (SMAS). Perichondrium covers the lower and upper lateral cartilages. In this study, nasal vascularization was compared between subperichondrial and supraperichondrial dissection in closed septorhinoplasty. METHODS: 95 patients and 41 volunteers were included in this study. Supraperichondrial dissection was performed in 48 patients and subperichondrial dissection was performed in 47 patients. To measure blood stream, laser doppler flowmetry (LDF) was used and measurements were done preoperatively, on the postoperative first week; 3rd month and first year. RESULTS: The nasal tip and dorsum measurements were similar between the preoperative and postoperative first year in both groups (p = 1.000). However, in the supraperichondrial dissection group, nasal tip measurements showed a significant increase between the preoperative and third postoperative months (p = 0.011). This increase was accompanied by an increase in the minimal blood stream (p = 0.014). CONCLUSION: Both subperichondrial and supraperichondrial dissection techniques are physiological and result in fewer complications with minimal permanent vascular damage. We believe incision plays a critical role but keeping the perichondrium intact is important for short-term angiogenesis, where long-term results showed no difference in vascularization.

Effects of the Autologous Platelet-Rich Plasma in Nasal Pack on Postoperative Quality of Life.

AIM: The authors aimed to research the effects of autologous platelet-rich plasma, which is known for the positive effects on wound healing, on postoperatif living quality of the patients after using on nasal surgery. METHODS: Patients who undergo nasal operation according to randomized patient's choice have been injected with saline merocel pack and platelet-rich plasma (PRP) in their nasal path. Postoperative is followed by 1 month; Nose Obstruction Symptom Evaluation (NOSE) scala score, bleeding, pain, and crust rate have been compared between 2 groups. RESULTS: As a result of the 1 month follow-up, it was seen that the treatment group experienced better results in terms of NOSE scale than the control group patients and this was significant difference in terms of NOSE. Less bleeding and crust was seen on the treatment group patients than the control group patients and statically significant difference was found. In terms of visual analogue scale score no statically significant difference was found between 2 groups. CONCLUSION: According to the authors' study on PRP, the authors found out that by using PRP wound can be healed faster in early period of postoperative. It was seen with the authors' research that on postoperative early period crusts, bleeding and postoperative complaints are lesser.

Plasma Glycated Albumin Levels Clearly Detect Hearing Loss and Atherosclerosis in Patients with Impaired Fasting Glucose.

OBJECTIVE: To describe the relationship between atherosclerosis and hearing thresholds in prediabetic patients with impaired fasting glucose (IFG) and to determine the efficacy of glycated albumin in predicting carotid artery atherosclerosis in patients with isolated IFG. SUBJECTS AND METHODS: The study included 82 patients (aged 53.73-80 years) divided into two groups based on fasting glucose levels, the IFG group: 59 patients (32 females, 54.2%), and the normal fasting plasma glucose level group: 23 patients (12 females, 52.2%). Patients underwent audiological testing to determine hearing thresholds, and carotid intima-media thickness (CIMT) was measured using carotid artery Doppler sonography. Multivariate analyses were performed to determine whether or not the plasma glycated albumin levels could predict hearing loss and CIMT. RESULTS: Patients in the IFG group (mean age: 59.8 ± 9.5 years) had higher hearing thresholds and pure-tone average scores (PTA) than those in the group with normal glucose levels (mean age: 56.2 ± 10.1 years) (left ear: 27.65 ± 8.85 vs. 25.75 ± 21.96 dB, p = 0.021; right ear: 29.22 ± 8.51 vs. 22.39 ± 6.99 dB, p = 0.001). The CIMT was significantly higher in the IFG group than the control group (0.75 ± 0.26 vs. 0.56 ± 0.16 mm, p < 0.001 for the left and 0.74 ± 0.26 vs. 0.51 ± 0.19 mm, p < 0.001 for the right carotid arteries). Glycated albumin levels were independently related with increased CIMT (left CIMT: r = 0.32, p = 0.003; right CIMT: r = 0.42, p < 0.001), and serum glycated albumin levels were significantly associated with PTA (left ear: r = 0.28, p = 0.01; right ear: r = 0.30, p = 0.006). CONCLUSION: Sensorineural hearing loss was more common in patients with IFG. Plasma glycated albumin levels were strongly correlated with CIMT and carotid plaques as a marker of atherosclerosis and with hearing impairment thought to develop due to atherosclerosis in patients with IFG.

A simple technique for removal of orbital tumors: transmaxillary approach.

In this article, we present the case of a 43-year-old female with a tumor of the orbital base. Computed tomography revealed a well-defined contrast enhancing cavernous hemangioma behind the left bulbus oculi. The surgical resection was performed by transmaxillary approach to the orbit. No clinical complications were observed during three-month follow-up following surgery.

The relationship between heterotopic gastric mucosa in the cervical esophagus and laryngopharyngeal reflux.

OBJECTIVES: This study aims to investigate the possible correlations between the heterotopic gastric mucosa (HGM) islets in the cervical esophagus and laryngopharyngeal reflux (LPR). PATIENTS AND METHODS: Between May 2010 and April 2011, 45 patients (36 females, 9 males; mean age 39.8±14.1 years; range 18 to 72 years) who had reflux symptom index (RSI) >10 and reflux finding score (RFS) >7 were included. The study group consisted of 21 patients who were diagnosed with HGM islets in the cervical esophagus, while control group consisted of 24 patients without any HGM islets assessed by upper gastrointestinal system endoscopy. Esophagus manometric examination and dual-channel 24-hour pH monitoring were performed on all patients. RESULTS: Pretreatment mean RSI and RFS were 25.6±3.5 and 15.1±3.4 in group 1, while it was found to be 21.1±4.4 and 11.9±2.6 in group 2 (p=0.001, p=0.001). A total of 29.7% of patients who underwent pH monitoring had distal reflux, whereas 43.2% of them had proximal reflux. In group 1, distal reflux was observed in 15.4% and proximal reflux was found in 54% of the patients, while distal reflux was observed in 38% and proximal reflux was found in 38% of the patients in group 2 (p=0.152; p=0.27). Fourteen patients diagnosed with HGM had antral- and seven patients had fundal-type epithelium. CONCLUSION: Our study results suggest that HGM islets may be considered as an etiological factor in the patients with severe LPR with isolated proximal reflux based on the 24-hour pH monitoring.

Efficiency of hypericum perforatum, povidone iodine, tincture benzoin and tretinoin on wound healing.

Different topical agents have been used to accelerate wound healing. The purpose of this study is to compare the safety and efficacy of topical application of the extract of Hypericum perforatum (HPE), povidone iodine (PI), tincture benzoin (TB) and tretinoin (T) on surgical wound healing. Ten adult female, Wistar albino rats were included in the study. HPE, PI, TB and T solutions were applied on the wounds. After seven days, tissue samples were collected and inflammatory cells, re-epithelialization, granulation tissue, angiogenesis, collagen accumulation, hemorrhage and lysis of cells were investigated histopathologically. No dermal toxicity was noted. HPE, TB, PI have all showed good epithelialization and granulation, but HPE showed the most advanced stage of healing within a short period of time. HPE had significantly higher values of re-epithelialization and collagen accumulation, but lower inflammatory cell count and granulation tissue. TB had the second best in re-epithelialization, collagen accumulation and the highest granulation tissue. PI induced better reepithelialization and granulation than the control group with remarkable cell lysis. As a result, HPE can be a safe, effective, and cheap agent that can be used for surgical wounds.

Supraclavicular thoracic duct cyst.

The thoracic duct cysts located in the supraclavicular region are very rare masses, the etiology of which is not completely known. This article presents the clinical follow-up of a 35-year-old male patient diagnosed with throracic duct cyst situated in the left supraclavicular region and the patient's condition is discussed in line with literature. The patient admitted to our clinic with a complaint of a mass in the left supraclavicular region that had appeared six months ago and that had been increasingly growing. A cyst excision under general anesthesia was performed to the patient who was pre-diagnosed with thoracic duct cyst following the radiological evaluation and the needle aspiration biopsy. There were no complications or a recurrence during the six months of postoperative follow-up.

Comparison of efficacy of different treatment methods in the treatment of idiopathic tinnitus.

OBJECTIVES: This study aims to detect whether any differences were present between betahistine dihydrochloride, transcutaneal electrical nerve stimulation and pure tone masking-tinnitus retraining therapy (TRT) methods in the effects on quality of life and treatment of the symptoms of the patients. PATIENTS AND METHODS: A total of 91 patients (42 females, 49 males; mean age 49.3±8.3 years; range 30 to 70 years) who admitted to the Otorhinolaryngology Clinic of the Ufuk University between June 2009 and June 2010 with a complaint of subjective tinnitus and who had no hearing loss were included in the study. In this study, the effects of these three treatment methods on healing and quality of life in patients suffering from bilateral subjective tinnitus were comparatively evaluated using Tinnitus Handicap Inventory Score (THIS), visual analog scale (VAS) and audiological parameters. The evaluations were made immediately before the treatment, immediately after the treatment and three weeks after the treatment. Kolmogorov-Smirnov analysis was used to test the normal distribution of the data and Wilcoxon signed rank test was used to show the differences between the different treatment methods before the treatment, immediately after the treatment and three weeks after the treatment. Mann-Whitney U and Kruskal-Wallis H tests were used to show the inter-group differences. RESULTS: In the inter-group analyzes, success rate of the pure tone masking-TRT was much higher when compared to the other treatment methods. In the evaluations performed at the end of the three-month period, it was seen that the efficacy of the treatment was continuing. CONCLUSION: According to these results, pure tone masking-TRT was found to be the best treatment method when compared to other methods and it was concluded that this treatment may be considered as the first choice in patients with idiopathic tinnitus.

[Isolated hypoglossal nerve paralysis: a case report]. / Izole hipoglossus sinir felci: bir olgu sunumu.

Cranial nerve paralysis is an uncommon complication of radiotherapy for head and neck carcinomas because cranial nerves are relatively resistant to radiation. The incidence of this complication has been declared to be 1-5% in different studies. Unlike the other cranial nerves, isolated hypoglossal nerve paralysis in patients who have been treated with radiotherapy for nasopharyngeal carcinomas is a worrisome sign of recurrence. We report a 45-year-old male patient admitted to our clinics with complaints of difficulty in moving his tongue and dysphasia five years after combined radiotherapy and chemotherapy for nasopharyngeal carcinoma. Recurrence of the tumor was thought to be the cause of the isolated hypoglossal nerve paralysis at first, however late toxicity of radiotherapy was found to be the etiological factor after detailed examinations.

Pulsatile oropharyngeal and neck mass caused by bilateral tortuous internal carotid artery: a case report.

The cervical course of the internal carotid artery is almost straight in contrast to the intracranial portions which are highly tortuous. The incidence of variations in the cervical course of the internal carotid artery of the population is approximately 10-40 percent. In this case report, a 76-year-old female patient with a pulsatile mass at the posterior oropharyngeal wall and anterior neck was presented. Physical examination revealed a pulsatile anterior neck mass, and a pulsatile mass at the right posterior wall of the oropharynx. Imaging revealed a bilateral tortuous internal carotid artery and segmental left internal carotid arterectomy and distal internal carotid artery - lateral common carotid artery anastamosis were performed with no postoperative complications.

Spontaneous displacement of silastic prosthesis 10 years after type 1 thyroplasty: a case report.

Implant dislocation following type 1 tyroplasty mostly results from the effects of triggering factors in the early postoperative period. A 42-year-old female patient who had had tyroplasty type 1 surgery with silastic implant, applied to our clinic with cough episodes, dyspnea and hoarseness following an upper airway infection 10 years after the surgery. In laryngeal endoscopic examination of the patient, white colored irregularity on anterior left vocal cord and left band ventricule fullness was seen. Regarding the patient's medical history, it was thought that the silastic prosthesis which had been implanted in the type 1 thyroplasty surgery might have displaced. The silastic prosthesis was removed by means of microsurgery technique through endolaryngeal way under general anesthesia. During the first month follow-up of the patient, dyspnea and hoarseness complaints were improved right away and she had no other problems. The causes and consequences of displacement of the prothesis which rarely occurs, after tyroplasty type 1 have been discussed along with the latest data in the literature.

[Zenker diverticulum: a case report]. / Zenker divertikülü: Olgu sunumu.

Zenker's diverticulum is a pulsion typed pharyngoeosophageal diverticle caused by the herniation of the pharyngeal mucosa, standing beside the posterior pharyngeal wall, through the Killian opening which is known as the weak area between the inferior constructor muscle's oblique fibres and transverse fibres of cricopharyngeal muscle. In patients with Zenker's diverticulum, symptoms such as disfagia, globus in the cervical area, weigh loss, regurgitation, cough, and aspiration. These patients are primarily admitted to the Gastroenterology and Othorhinolaryngology clinics with the complaint of disfagia and the diagnosis of this disease is mostly established late and the treatment is started late because the results of their physical examinations seem normal. Therefore, especially in the patients who have disfagia complaint, pharyngoeosophageal diverticle prediagnosis should be thought and that should be examined by passage graphies with barium and endoscopic methods, if needed. In this article, we presented the 67-year-old Zenker's diverticulum patient in whom we performed open diverticulectomy and posterior cricopharyngeal myotomy, and we specified the important points in choosing the patient and the type of surgery.

Presence of vascular loops entering internal acoustic channel may increase risk of Sudden sensorineural hearing loss and reduce recovery of these patients.

OBJECTIVES/HYPOTHESIS: To analyze whether there is correlation between branching patterns of anterior inferior cerebellar artery/posterior inferior cerebellar artery (AICA/PICA) in cerebellopontine angle (CPA) area, as demonstrated by three-dimensional fast imaging employing steady-state acquisition (3D FIESTA) magnetic resonance imaging (MRI) and 1) idiopathic sudden sensorineural hearing loss (ISSNHL) outcomes and 2) recovery of ISSNHL. STUDY DESIGN: We evaluated patients with idiopathic SSNHL for branching patterns of AICA/PICA in CPA area, as demonstrated by 3D FIESTA MRI. METHODS: Sixty-eight patients with SSNHL (32 [47.1%] women; mean age 45.3 ± 14.6 [minimum-maximum: 18-77]) and 38 healthy volunteers [17 (44.7%) women; mean age 48.6 ± 14.0 (minimum-maximum: 26-81)] were included in this study. We evaluated patients for branching patterns and classified as type IA, IB, IIA, and IIB. Branching patterns were evaluated at the diseased side of the patients and both sides of the control group. Pretreatment and posttreatment audiological values were also studied. RESULTS: AICA/PICA branching patterns in control group versus study group in the affected side were: 26 (34.2%) versus 12 (17.6%) subjects had type IA; seven (9.2%) versus nine (13.2%) subjects had type IB; 31 (40.8%) versus 23 (33.8%) subjects had type IIA; and 12 (15.8) versus 24 (35.3%) subjects had type IIB branching patterns, respectively. Presence of vascular loops entering internal acoustic channel (type IIB branching pattern) was more prominent in the study group (P = 0.017). In addition, type IIB branching pattern was significantly associated with unresponsiveness to treatment (18 [75%] of 24 patients with type IIB were unresponsive and 14 [47.0%] of 30 patients with nontype IIB were unresponsive, P < 0.001). CONCLUSION: Type IIB branching pattern has been shown to be more common in patients with ISSNHL, and these patients come across with unresponsiveness to standard therapy more than the other branching types. LEVEL OF EVIDENCE: 3b. Laryngoscope, 127:210-215, 2017.

Platelet-Rich Plasma Application for Acute Tympanic Membrane Perforations.

OBJECTIVE: To assess the efficacy of the application of platelet-rich plasma (PRP) in the healing process of acute tympanic membrane perforations (TMPs). MATERIALS AND METHODS: Acute TMPs were made in both the ears of 12 New Zealand rabbits. Plasma gel was applied at the right tympanic membrane (TM) of the same animal until the perforations were closed. The left TM was left untreated. On days 1, 4, 7, 10, 13, 16, 21, 28, and 35, the TMs were monitored to check the closure of perforations. The days of perforation closure for the 2 groups were compared using the paired t-test. The animals were sacrificed 2 months after making the perforations. Seven histopathological parameters were reviewed by 2 blinded pathologists: acute inflammation, chronic inflammation, edema in the lamina propria, congestion in the lamina propria, sclerosis, fibroblastic reaction, and an increase in the thickness of the squamous epithelial layer. The presence or absence of each histological parameter in both groups was compared using the Pearson Chi-square test. RESULTS: The average number of days for closure in the plasma gel group was 12 (range 8-18 days) and that in the control group was 17.7 (range 8-31 days). The difference was statistically significant (p=0.0145). There was no sclerosis or fibroblastic reaction in any of the specimens. No statistically significant difference was seen between the 2 groups with respect to acute inflammation, chronic inflammation, edema in the lamina propria, congestion in the lamina propria, and an increase in thickness of the squamous epithelial layer (p>0.05). CONCLUSION: Platelet-rich plasma fastens TMP closure; in long term, the eventual outcome is both microscopically and macroscopically same for the control as well as study groups in a rabbit traumatic TMP model. We believe that this study will encourage the clinical use of PRP for acute TMPs and trigger clinical studies in this field.

A hystopathological study of thyroarytenoid muscle invasion in early (T1) glottic carcinoma.

PATIENTS AND METHODS: Surgical specimens belonging to 16 patients who underwent partial laryngectomy for T1 glottic cancer were subjected to detailed histopathologic examination; 11 of the patients were staged as T1a while 5 were staged as T1b. RESULTS: It was detected that in 11 patients the tumor was confined to the mucosal or submucosal connective layer, and in 5 (31.2%) cases, the tumor invaded the thyroarytenoid (TA) muscle. In cases involving the one-third anterior part of the vocal cords and the anterior commissure, a 50% (4/8) TA muscle invasion was detected. DISCUSSION AND CONCLUSION: Our finding TA muscle invasion at the rate of 31.2% in our 16 case series clinically staged as T1 revealed that deep invasion did not always impair the vocal cord mobility. Observing TA muscle invasion at the rate of 50% in cases involving the one-third anterior part of the vocal cord and the anterior commissure suggested that TA muscle invasion in the anterior part did not significantly impair mobility.

Efficacy of platelet-rich fibrin matrix on viability of diced cartilage grafts in a rabbit model.

OBJECTIVES/HYPOTHESIS: The objective of this study was to compare the viability of cartilage grafts embedded in platelet-rich fibrin matrix (PRFM) wrapped with no material (bare diced cartilage grafts), oxidized methylcellulose (Surgicel), or acellular dermal tissue (AlloDerm). STUDY DESIGN: Experimental study. METHODS: In this study, six New Zealand rabbits were used. Cartilage grafts including perichondrium were excised from each ear and diced into 2-mm-by 2-mm pieces. There were four comparison groups: 1) group A, diced cartilage (not wrapped with any material); 2) group B, diced cartilage wrapped with AlloDerm; 3) group C, diced cartilage grafts wrapped with Surgicel; and 4) group D, diced cartilage wrapped with PRFM. Four cartilage grafts were implanted under the skin at the back of each rabbit. All rabbits were sacrificed at the end of 10 weeks. The cartilages were stained with hematoxylin-eosin, Masson's Trichrome, and Orcein. After that, they were evaluated for the viability of chondrocytes, collagen content, fibrillar structure of matrix, and changes in peripheral tissues. RESULTS: When the viability of chondrocytes, the content of fiber in matrix, and changes in peripheral tissues were compared, the cartilage embedded in the PRFM group was statistically significantly higher than in the other groups (P < 0.05). CONCLUSION: We concluded that PRFM has significant advantages in ensuring the chondrocyte viability of diced cartilage grafts. It is also biocompatible, with relatively lesser inflammation and fibrosis.

Temporal Bone Posterior Wall Defect, a New Clinic Entity?

OBJECTIVE: To define clinical and audiological findings in patients with temporal bone posterior wall defects (TBPWD) and to investigate possible relationships between these findings and the characteristics of the defect. MATERIALS AND METHODS: The computed tomography (CT) views of 1198 patients with vestibulocochlear symptoms between 2007 and 2012 were retrospectively evaluated, and TBPWD and associated anomalies were investigated. Patients who had TBPWD were called back, and clinical and audiological examinations (tympanometry, pure tone audiometry, acoustic reflexes, and otoacoustic emission) were performed. RESULTS: Twenty-eight (2.34%) patients had TBPWD. Twenty-three of them were eligible for the study. Size of the defect was significantly correlated with the presence of tinnitus and/or vertigo (p<0.005). The cut-off values for the largest size of TBPWD were 1.65 mm [sensitivity: 0.67 and specificity: 0.77 (95% CI: 0.58-0.97); p=0.04] in case of the presence of tinnitus and 1.85 for vertigo (sensitivity: 0.78 and specificity: 0.86 (95% CI: 0.67-0.99); p=0.006). In pure tone audiometry tests, mixed-type hearing loss was present in four (17%) patients, sensorineural hearing loss was present in three (13%) patients, and conductive-type hearing loss was present only in one (4%) patient. Otoacoustic emission tests revealed significant differences in signal/noise ratios at frequencies of 500, 750, 1000, and 6000 Hz. CONCLUSION: For the first time in the literature, we defined clinical and audiological findings in patients with TBPWDs. These defects seem to cause more prevalent symptoms of vertigo and tinnitus and disturb the audiological characteristics of patients.

Do micrometastases detected with cytokeratin immunoperoxidase reactivity affect the treatment approach to neck in supraglottic cancers?

OBJECTIVES: The aim of this study was to determine the occult lymph node metastasis rates with immunoperoxidase staining for cytokeratin in supraglottic larynx cancers and to assess our approach to the neck. STUDY DESIGN: Twenty-two patients who had squamous cell carcinoma in the supraglottic region and no histopathologic metastasis in the neck who had their cancer detected with the use of hematoxylin-eosin were included in the study. All of the specimens were reevaluated with the use of immunoperoxidase staining for cytokeratin. RESULTS: Micrometastatic disease (pN1) has been detected in 3 patients (13.61%) in whom no metastasis was detected with routine histopathologic examination. CONCLUSION AND SIGNIFICANCE: Results suggest that the occult metastasis rates are higher than those detected with routine hematoxylin-eosin staining. However, because it is accepted that neck dissection alone has adequate therapeutic efficiency in pN1 patients, the detected 13.61% rate of micrometastases has not changed our treatment plan in the neck.

Cochlear implantation in children with inner ear malformations: report of two cases.

UNLABELLED: Cochlear implantation of congenitally deaf children with inner ear malformations is gaining special interest. Although the number of the reported cases is increasing, the decision for implantation needs thorough investigation. Preoperative evaluation, surgical approach and postoperative follow-up can be challenging. STUDY DESIGN: A retrospective analysis of two cases with inner ear malformations. PATIENTS: One patient was a 3-year-old-girl who had cochlear and cochleovestibular nerve aplasia on the left side and incomplete partition on the other side. The other patient was a 5-year-old-boy who had hypoplastic cochlea on both sides. Both of them also had vestibular anomalies. Cases were implanted by using multichannel cochlear implant. RESULTS: No complications were encountered. Both patients responded to acoustic stimuli, and their speech perception skills were improved. After 10 months of cochlear implant use, their results seem encouraging. CONCLUSION: Except cochlear or cochleovestibular nerve agenesis, inner ear malformations cannot be accepted as a contraindication for cochlear implantation. Although there can be difficulties during the surgery or in the postoperative period, patients with inner ear malformations can also benefit from cochlear implantation. It is essential that all possible complications and postoperative performance should be discussed with the parents.

[Approach to the recurrent laryngeal nerve in thyroid surgery]. / Tiroit cerrahisinde rekürrent larenjeal sinire yaklasimimiz.

OBJECTIVES: We evaluated our surgical approach to the identification of the recurrent laryngeal nerve (RLN) under the guidance of operation microscope and RLN dissections during thyroidectomy. PATIENTS AND METHODS: Twenty-three patients (20 females, 3 males; mean age 37 years) undergoing thyroidectomy were included in the study. Thirty RLN dissections were performed, being unilateral in 16 patients, and bilateral in seven patients. The recurrent laryngeal nerves were identified at the inferior thoracic inlet with the use of the operation microscope having an ocular lens of 250 mm, followed by a total dissection up to the laryngeal entrance. Endoscopic laryngeal examinations were performed for vocal cord movements one day before surgery and postoperatively on days 1, 3, and 7. RESULTS: No abnormal vocal cord movements were detected preoperatively. Following surgery, none of the patients developed persistent RLN paralysis. Two patients exhibited transient vocal cord paralysis (limitation in vocal cord movements). The use of the operation microscope for RLN dissections resulted in prolongation of the operation time ranging from 15 to 40 minutes for each side, which tended to decrease with enhanced experience of the surgeon. CONCLUSION: The use of the operation microscope enables safe RLN dissections during thyroidectomy operations.