Topographic anatomy of the endolymphatic sac: a pilot cadaveric dissection study.

PURPOSE: The precise location of the endolymphatic sac (ES) may be difficult during surgical approaches. This morphometric study aimed to determine the exact location of ES in adult human cadavers for the management of pathologies such as Meniere's disease. METHODS: Twenty temporal bones of 10 adult cadavers (mean age: 70 ± 13.40 years, range: 45-92 years; sex: 4 males and 6 females) fixed with 10% formalin were bilaterally dissected to obtain numeric data about the location of ES. RESULTS: Distances of ES to the posterior semicircular canal (PSC), Donaldson line (DL), sigmoid sinus (SS) and sinodural angle (SA) were found as 2.76 ± 1.18 (0.96-5.58) mm, 1.74 ± 1.13 (0.58-5.07) mm, 2.30 ± 1.09 (0.54-4.91) mm and 16.04 ± 3.15 (9.82-22.18) mm, respectively. In addition, the angle between the tangents passing through the cortical bone (CB) and SS was determined as 35.37°±11.32° (21.30°-60.58°). No statistical difference was found between right-left or male-female measurements (p > 0.05). CONCLUSION: DL, SS, and PSC are essential anatomical landmarks for determining the location of ES. The spatial location of SS, including its depth to the cortical bone and the distance to anteriorly located anatomical structures of the mastoid cavity consisting of the facial nerve and PSC, is believed to be underlined for ES surgery. Our data may be used as a database to further define the relationship between ES and adjacent anatomical structures (SS, PSC, etc.) during the application of surgical approaches.

Anatomical Analysis of the Eustachian Tube in the Temporal Bone Through the Middle Fossa Window.

PURPOSE: This cadaveric anatomical study aimed to explore precise morphometric measurements of the eustachian tube (ET) and adjacent structures in the middle cranial fossa, focusing on identifying reliable surgical landmarks when traditional markers are compromised due to tumors or trauma. METHODS: Twenty-two temporal bones from 11 adult cadavers (mean age: 75.70 ± 13.75 yr, range: 40-90 yr; sex: 5 females and 6 males) were dissected bilaterally. Surgical tools, including an operation microscope, endoscope, and digital caliper, were used for meticulous measurements. Parameters such as ET dimensions, distances between key points, and relevant angles were quantified, ensuring precise anatomical data. RESULTS: ET width at the foramen spinosum (FS) level, the midline level, and the eustachian orifice level were measured as 2.18 ± 0.68, 2.42 ± 0.70, and 2.30 ± 0.74 mm, respectively. The distances from the zygomatic root (ZR) to FS, ET, superior semicircular canal (SSC), and internal carotid artery (ICA) were 29.61 ± 2.56, 23.28 ± 2.61, 26.53 ± 2.56, and 32.61 ± 3.69 mm, respectively. The angles between SSC-ZR-ICA and FS-ZR-ICA were measured as 36.57 ± 10.32 and 13.63 ± 3.72 degrees, respectively. No statistical difference was found between right-left or male-female measurements ( p > 0.05). CONCLUSION: The present study offers invaluable insights for neurotological surgeons performing middle fossa approaches. ET and ZR may serve as crucial reference points, enhancing surgical orientation and minimizing risks during complex procedures. These precise anatomical data may empower surgeons, ensuring safer and more confident middle cranial fossa operations, even in challenging clinical scenarios.

Cochleo-facial corridor to the vestibule and fundus of the internal auditory canal through oval window: a minimal invasive and cochlea sparing approach.

PURPOSE: This cadaveric work aimed to test the effectiveness of a modified surgical corridor (ExpTSA: expanded transcanal supracochlear approach) developed for anatomic cochlear preservation in selected vestibular schwannoma patients necessitating to perform cochlear implantation for appropriate cases to achieve the best outcome. METHODS: The ears of 10 cadavers (at mean age 75.70 ± 13.75 years, range 45-92 years) were dissected from the external auditory canal (EAC) to the internal auditory canal by ExpTSA under the guidance of a microscope and endoscope. All stages of the surgical process were recorded step by step and evaluated morphometrically. RESULTS: The vestibular base was successfully reached in all ears without damaging the cochlear morphology and facial nerve. The vestibular base was 23.33 ± 2.02 mm away from the entrance (external orifice) and 10.26 ± 1.33 mm from the exit (internal orifice) of EAC. The oval window and vestibular base were measured to be 2.94 ± 1.05 mm and 5.87 ± 1.24 mm deep from the facial nerve, respectively. The normal areas of the oval window, the exit and entrance of EAC were found as 2.90 ± 0.81 mm2, 42.52 ± 13.66 mm2, and 110.73 ± 25.32 mm2, respectively. After ExpTSA procedure, the areas of the oval window (11.04 ± 2.83 mm2), the exit (122.45 ± 20.41 mm2) and entrance (167.49 ± 30.94 mm2) of EAC were expanded approximately 280%, 188%, and 50%, respectively. CONCLUSION: The ExpTSA may be performed for accessing to the vestibule and fundus of IAC for tumor removal of intravestibular schwannoma patients (with or without fundus involvement) with unserviceable hearing, preserving the cochlear morphology.

Microsurgical anatomy of the stapedius muscle in adult cadavers.

This study aimed to establish an extended morphometric dataset regarding the stapedius muscle for anatomists and otologists. The tympanic cavity of ten cadavers (five females, five males) aged with 75.70 ± 13.75 years was bilaterally dissected. Morphometric properties of the stapedius muscle (i.e., its muscular belly and tendon) and its relationship with the neighborhood structures including the facial nerve was evaluated. The length of the entire stapedius muscle was found as 4.80 ± 1.13 mm. The depth between the entrance of the external auditory canal and stapedius muscle was measured as 18.23 ± 2.30 mm. The incudostapedial joint and stapedial tendon were found to be 1.66 ± 0.25 mm and 1.18 ± 0.19 mm away from the facial nerve, respectively. The stapedial tendon length was standardized as five types: Type 1, extremely short tendon (under 0.5 mm), 5% of cases; Type 2, short tendon (between 0.5 and 1 mm), 30% of cases; Type 3, normal tendon (between 1 and 2 mm), 55% of cases; Type 4, long tendon (between 2 and 2.5 mm), 10% of cases; and Type 5, extremely long tendon (above 2.5 mm), no cases. Our findings showed that the stapedius tendon size in adults was quite similar to fetuses. Therefore, probably entire muscle dimension does not alter after birth. Considering the concordance between direct anatomic (our findings) and radiologic measurements (literature findings) of the stapedius muscle, preoperative radiological evaluation may be important for otologists in terms of the choice of surgical tools such as diamond burr sizes. Due to the lack of standardization regarding the evaluation of the stapedius tendon size (i.e., extremely short or extremely long), we defined the tendons below 0.5 mm as extremely short (Type 1) and above 2.5 mm as extremely long (Type 5).

A Computed Tomography Study of the Prechiasmatic Sulcus Anatomy in Children.

PURPOSE: To investigate the characteristics of the prechiasmatic sulcus in children aged between 1-20 years. METHODS: Patient files of 200 children admitted to the university hospital on 2019 were analyzed, retrospectively. The computed tomography images of patients were used to obtain anatomical knowledge containing prechiasmatic sulcus types and dimensions. RESULTS: The measurements related to the sulcal length (6.94 ± 1.25 mm) and sulcal angle (31.01 ± 18.13°) showed that the sulcal length did not alter in children between 1 and 20 years, whereas the sulcal angle did not vary from infancy to prepubescent period, but it was decreasing in postpubescent period. In 29 patients, the sulcal length was observed to divide into 2 parts with an evident angle. The interoptic distance and planum length were found as follows: 14.70 ± 2.85 mm and 14.84 ± 4.12 mm, respectively. The order of PS types was observed as type 4 (26.5%, 53 cases) > type 2 (26%, 52 cases) > type 1 (24%, 48 cases) > type 3 (23.5%, 47 cases). CONCLUSIONS: The sulcal length did not vary in children, whereas the sulcal angle decreased with an irregular pattern. The sulcal angle decreased after prepubescent period, possibly due to the sphenoid sinus pneumatization and spheno-occipital synchondrosis. The sulcal length angle mostly in infants and young children may cause surgical orientation difficult during the resection of tumors using transcranial approaches.

Anatomy of the Anterior Clinoid Process in Human Fetuses.

PURPOSE: The main objective of this study was to display the morphologic properties of the anterior clinoid process (ACP) in human fetuses in term of early childhood surgeries. METHODS: Twenty-four (10 females and 14 males) fetal cadavers aged from 16th to 28th weeks of gestation (at mean, 21.54 ±â€Š3.11 weeks) were included in the present study. The dimensions of ACP were measured with a digital image analysis software. RESULTS: Taking into account the length, width, and angle of ACP, it was classified as Type 1 in 20.83% (10 cases), Type 2 in 10.42% (5 cases), Type 3 in 10.42% (5 cases), Type 4 in 2.08% (1 case), Type 5 in 8.33% (4 cases), Type 6 in 16.67% (8 cases), Type 7 in 8.33% (4 cases), and Type 8 in 22.92% (11 cases). According to the attachment site of the optic strut (OS) relative to ACP, OS was identified as the anterior 3/5 in 16.67% (8 cases), anterior 4/5 in 68.75% (33 cases), and posterior 1/5 in 14.58% (7 cases). Neither right-left nor male-female significant differences were observed between the quantitative values belonging to ACP and OS. CONCLUSION: The percentage of the most complex and challenging type of ACP (the long, narrow, and narrow-angled ACP) in fetuses was found to be close to adults. Thus, routine adult surgical procedures such as anterior clinoidectomy might be successfully used in young children and infants. The attachment site of OS relative to ACP in adults was more anterior according to fetuses probably due to postnatal development such as the pneumatization of the sphenoid bone. In this regard, for pediatric neurosurgeons to avoid iatrogenic injuries and to select appropriate surgical approaches, further studies conducted on the attachment of OS relative to ACP in children are needed.

Evaluation of the Foramen Magnum Area Calculated by Different Methods: A Radioanatomic Study.

PURPOSE: The main objective of the study was to evaluate the probable diversity in the area of the foramen magnum (FM) calculated by different measuring methods. METHODS: The study was conducted on 24 dry skulls, present in the collection of the Anatomy Department, Faculty of Medicine, Mersin University. The area of FM was calculated by different measurement methods including automatic field setting, Teixeria and Radinsky formulas obtained from anatomic (ASM), photographic (PSM) and radiologic (RSM) skull measurements. RESULTS: The areas of FMs calculated by Teixeria formula in RSM, PSM, and ASM were as follows: 857.96 ±â€Š99.97 mm, 796.68 ±â€Š105.08 mm, and 820.86 ±â€Š96.40 mm, respectively. The areas calculated by Radinsky formula in RSM, PSM, and ASM were as follows: 851.37 ±â€Š99.68 mm, 792.63 ±â€Š104.18 mm, and 814.85 ±â€Š94.99 mm, respectively. Lastly, the areas calculated by the automatic field setting of RSM and PSM software were as follows: 799.75 ±â€Š103.38 mm and 752.83 ±â€Š105.60 mm, respectively. CONCLUSION: Statistical significance was observed between the areas of FM obtained from RSM, ASM, and PSM when calculated by the automatic field setting, Teixeria formula, and Radinsky formula. The authors think that considering the amorphous shape of FM, the automatic field setting of the software should be used to obtain the most accurate numerical data related to the area of FM.

The Measurement of Various Anatomical Structures and Assessment of Morphometric Development of Fetal Skull Base.

BACKGROUND: As the skull base has a complex anatomy, we underline the importance of anomalies for side asymmetry. It is useful to investigate relationship between anatomical structures for the surgical procedure orientations. Dural adherence, enlarged superior petrosal sinus, influence of neural crest cells, and cranial base ossification are among the factors in morphometric growth on skull base. MATERIAL AND METHODS: Twenty-five fetuses of an estimated gestational age ranging from 17 to 34 weeks were studied in the Anatomy Laboratory of Mersin University Medical Faculty. Craniotomy was made to each fetus and brain hemispheres were dissected. We put plates, passing from the external points of lateral and anterior-posterior borders of fetus heads that are perpendicular to each other. An analytical calculation was formulated for the angle of foraminae to the root of zygoma by using different formulations depending on their posterior or anterior location to the root of zygoma. Statistical method was based on correlation analysis, simple regression, independent 2 group t tests, SPSS20.0, and MedCalc 11.5 (MedicReS, New York, NY). RESULTS: Neither side dominance for the jugular foramen, nor the differences of foramen rotundum, spinosum, and ovale to anterior skull wall, root of zygoma, and to midline were found to be significant. CONCLUSION: There is a debate on asymmetry of foramina of the skull base. No certain consensus about the initiation time and the causes of asymmetry in the past was documented. Studies are to be encouraged to further enlighten pre-postnatal factors affecting the fetal skull base morphometrism.

Is mycophenolate mofetil an alternative agent to corticosteroids in traumatic nerve paralysis?

OBJECTIVE: The effects of an immunosuppressive agent, mycophenolate mofetil (MM), were investigated and compared with those of methylprednisolone (MP) and dexamethasone (DXM) on the traumatic nerve function. STUDY DESIGN: This is a randomized controlled animal study. MATERIALS AND METHODS: This experimental study was performed on 84 male Wistar albino rats. The rats were assigned to 12 groups each consisting of 7 animals. The groups were formed according to application of normal-dose DXM (group 1A-B), high-dose MP (group 2A-B), normal-dose MP (group 3A-B), MM (group 4A-B), and MM with high-dose MP combination therapies (group VA-B). Right sciatic nerve dissection was performed, and compound muscle action potential thresholds were recorded. The nerve was traumatized with the compression of a Jeweller forceps for 20 seconds. Posttraumatic thresholds were also recorded. The compound muscle action potential thresholds were recorded in the first and fourth weeks for the assigned groups. Then, the nerve was transected and prepared for electron microscopic and histopathologic examinations. Nitric oxide and malondialdehyde assessments were performed on both tissue and blood samples. RESULTS: Only the MM and MP+MM groups had satisfactory electron microscopic findings and were about to reach the tissue characteristics of the control animals. Despite the electrophysiologic recovery, the DXM group was found to have poor electron microscopic scoring. CONCLUSIONS: Mycophenolate mofetil has been found to be beneficial in the treatment of traumatic nerve paralysis. Although a complementary investigation is needed, this immunosuppressive agent may be an alternative to corticosteroids for the selected cases where steroid therapy is contraindicated.

The computed tomographical and tympanometrical evaluation of mastoid pneumatization and attic blockage in patients with chronic otitis media with effusion.

OBJECTIVE: To assess the relation between mastoid size and attic blockage in COME patients treated with ventilation tube insertion and prognosis regarding tympanometric compliance and computed tomography findings of temporal bones. MATERIAL AND METHODS: Twenty-four ears of 15 patients with chronic otitis media with effusion were selected prospectively. The ages of patients were between 5 and 13 years old and eight of them were females. All patient received medical treatment for 10 days. Ventilation tubes were inserted with or without adenoidectomy or adenotonsillectomy to the unimproved patients. Postoperative compliances were measured on first day, first week, and first month and the tympanometric results were compared each one with others and with mastoid pneumatization degree using computerized tomographic findings. RESULTS: The hearing thresholds were between 23 and 43 dB in left ears and between 22 and 45 dB in right ears. Mastoid pneumatization and aditus were normal and open in three (12.6%); sclerotic and open in eight (33.3%); sclerotic and blocked in 13 patients (54.1%), when the temporal bones assessed by computerized tomography. The mean compliance values of patients elevated postoperatively in regard with time and this increase was significant. There was a significant statistical relation between mastoid pneumatization and compliance of the ears. CONCLUSION: Tympanometric assessment may be considered as a valuable and cost-effective method rather than CT in the evaluation of aditus blockage and residual soft tissue of the tympanomastoid region.

An unusual presentation of neck dermoid cyst.

Congenital masses are the most common non-inflammatory neck lesions in children. Although usually present at birth, they can appear at any age. Dermoid cysts are benign lesions of congenital origin usually presenting as a midline neck mass. They rarely appear in the lateral region of the neck. Lateral cervical dermoid cyst is presented as a rare, unusual case, and differential diagnosis and management are discussed in light of recent literature.

Antrochoanal polyp: a transmission electron and light microscopic study.

Antrochoanal polyp (ACP) is a soft tissue mass originating from the maxillary antrum, emerging from the ostium and extending to the choana through the nasal cavity. Our aim was to investigate the light microscopic and ultrastructural features of ACP and to compare these with nasal polyps originating from the middle meatus (MMP). Seven ACP and seven MMP specimens were evaluated by transmission electron microscopy (TEM) and light microscopy. TEM examination showed epithelial cells with intact cilia covering both polyps. In some MMP cases, degeneration of the epithelium associated with some cilia loss was noted. Goblet cell hyperplasia was more prominent in MMP cases. Degeneration and partial destruction of the endothelial cells of the blood vessels were common findings in ACP cases; however, in the MMP group, endothelial cells were mostly intact with a few aggregates of ribosomes, and intact cell junctions were noted. Light microscopic examination revealed that inflammatory cells in the ACP group were numerous. However, eosinophils were predominant in MMP cases. Squamous metaplasia of the surface epithelium was detected in five ACP cases, but in none of the MMP cases. Basement membrane thickening was detected in two cases of the ACP and in four cases of the MMP group. There was a statistically significant difference between the two groups for inflammatory cells, eosinophilic cell infiltration, squamous cell metaplasia, endothelial cell destruction and goblet cell metaplasia. In conclusion, the low number of eosinophils, the high number of other inflammatory cells, the normal appearing basement membrane and intact and normal surface epithelium may reveal that the etiology of ACP might arise from chronic inflammatory processes rather than allergy. The destruction of the endothelium may be considered as a further sign of chronic inflammation.

Bronchoscopy induces intestinal mucosal barrier dysfunction: a possible role for nitric oxide.

OBJECTIVE: This study investigates the effect of bronchoscopy on intestinal mucosal barrier function and its association with intestinal nitric oxide production. METHODS: 30 rats were used. The study group (n=15) underwent rigid bronchoscopy. At 24 h following bronchoscopy, ileal nitrite/nitrate levels were evaluated. The ileum was also examined for mucosal damage, and graded according Chiu's histologic injury scale. RESULTS: In the bronchoscopy group, the ileal nitrite/nitrate levels were significantly higher than those of controls (398.5 +/- 85.1 and 44.5 +/- 6.6 nmol/g tissue, respectively, P=0.001). In the bronchoscopy group, the mucosal damage was significant, compared with those of controls (mean ranks, 22.8 and 8.2, P<0.0001). The changes varied from denuded villi and dilated capillaries to significant architectural distortion, lamina propria disintegration, ulceration and hemorrhage. Significant correlation was found between ileal nitrite/nitrate levels and mucosal damage in the bronchoscopy group (rs=0.56, P=0.03). CONCLUSION: This study suggests that bronchoscopy induces intestinal mucosal barrier dysfunction in association with excess intestinal nitric oxide production. These events may be involved in mechanisms responsible for bacterial translocation after bronchoscopy.

The inhibitory effect of topical N-acetylcysteine application on myringosclerosis in perforated rat tympanic membrane.

OBJECTIVE: Myringosclerosis often occurs in patients in whom ventilation tube insertion and tympanoplasty procedures are performed. Recent studies have revealed a relationship between the development of myringosclerosis and oxygen-derived free radicals, and some investigations have demonstrated that free radical scavengers prevent the development of myringosclerosis. N-acetylcysteine is a well-known anti-oxidant and anti-inflammatory agent. In this study, we aimed to investigate the preventive effect of N-acetylcysteine on myringosclerosis in myringotomized rat tympanic membranes. METHODS: Twenty Sprague-Dawley rats were bilaterally myringotomized and divided into four groups. Group 1 received no treatment, group 2 was treated with topical saline solution in Spongostan, group 3 received topical 0.6 mg N-acetylcysteine in Spongostan and group 4 received 1.2 mg N-acetylcysteine in Spongostan daily for 12 days. Tympanic membranes were examined by otomicroscopy on day 12. Then, the membranes were harvested and evaluated histologically by light microscopy. RESULTS: The tympanic membranes of groups 1 and 2 (saline and non-treated) showed extensive occurrence of myringosclerosis, whereas groups 3 and 4 (treated with N-acetylcysteine) showed lesser occurrence of myringosclerosis in otomicroscopic evaluation (P<0.01). Under light microscopic examination, lamina propria of pars tensa was found thicker in groups 3 and 4 when compared with groups 1 and 2. There was no significant difference between groups 3 and 4 (P: 0.30). CONCLUSIONS: Topically applied N-acetylcysteine was found to be effective in the prevention of sclerotic lesions in myringotomized rat tympanic membranes.

The effect of local administration of N-acetylcysteine in perforated rat tympanic membrane: an experimental study in myringosclerosis.

Myringosclerosis (MyS) is a common sequela of acute and chronic otitis media and ventilation tube treatment of serous otitis media. We aimed to study the effect of topical administration of N -acetylcysteine (NAC) on MyS by assessment of otomicroscopic evaluation, lipid peroxidation and nitric oxide (NO) (nitrite/nitrate) levels in experimental myringotomized rat tympanic membrane. Thirty adult rats were used and the upper posterior quadrant of the tympanic membranes of rats was myringotomized. Thereafter, they were divided into four groups. Group I received no treatment, group II was treated with saline, groups III and IV were treated with topical NAC (0.1 ml of 6 and 12 mg ml(-1), respectively). The levels of nitrite/nitrate and malondialdehyde (MDA) were measured in serum samples. In the otomicroscopic evaluation, non-treated and saline treated ears (controls) showed extensive occurrence of myringosclerotic plaques. Groups III and IV showed fewer occurrences of sclerotic plaques. There was no significant difference between groups III and IV regarding the development of MyS. The development of myringosclerotic lesion was found to be significantly different between NAC treated groups (III and IV) and the control groups (I and II). The levels of nitrite/nitrate of both groups III and IV were significantly lower than the control groups. The levels of MDA of these groups were also significantly lower than the control group. The relationship between groups III and IV was not statistically significant for the levels of nitrite/nitrate and MDA. We conclude that the topical treatment of NAC reduces the levels of MDA and NO products in rats. These results suggest that topical NAC application may be useful for the prevention of MyS.