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.

Evaluation of Bell's palsy in the cerebellopontine angle: An MRI study.

BACKGROUND: Evaluation of cranial nerve morphology through measuring cross-sectional area (CSA) on magnetic resonance imaging (MRI) is increasing day-by-day in clinical diseases. In Bell's palsy (BP), the manifestation of the enlarged CSA of the facial nerve (FN) may be used for diagnosis. This study aims to evaluate whether there is an enlargement of the cisternal FN in BP. METHODS: This retrospective study included 43 patients diagnosed with BP. In the reconstructed MRI, the long (LD) and short (SD) diameters of the paralytic and normal sides of the FNs located in the cerebellopontine angle were measured, and the CSA was calculated using the Radinsky formula. Before the radiologic measurement, a preliminary experiment was carried out on the rat sciatic nerve to be able to determine the actual nerve boundary on MRI. FINDINGS: There was a statistically significant relationship between paralytic and normal sides in the measurements of LD, SD, and CSA. The paralytic side was larger than the normal side in the cisternal FN. According to the Receiver Operating Characteristic (ROC) curve, BP can be estimated with 60% sensitivity and 70% specificity by the CSA of the FN more than 1.04 mm2 . As a result of the preliminary experiment, it was found that the actual nerve boundary was at approximately 50% intensity between the minimum and maximum values. CONCLUSION: Although entrapment of FN in the labyrinthine segment in BP was known, this study showed that the cisternal FN, which could be evaluated more conveniently, enlarged in the paralytic side compared with the normal side, and revealed the necessity of performing the comparison amongst the MRI studies on BP patients by a standardised measurement method. This study will also help clinicians to make a decision in the diagnosis of BP by giving a cut-off value for the CSA.

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.

Quantitative Analysis of the Vascular and Neural Compartments of the Jugular Foramen in Dry Skulls.

AIM: To compare the right and left sides and the endo?exocranial orifices of the jugular foramen (JF) considering the vascular compartment (VC) and the neural compartment (NC). MATERIAL AND METHODS: A total of 20 human dry skulls belonging to the inventory of Medical Faculty, Department of Anatomy, were included in this study. Numerical values were obtained using direct anatomical and also computed tomography measurements. RESULTS: The endocranial and exocranial VC occupied wider areas on the right side than on the left side (p < 0.05). However, there was no statistically significant difference between the surface area of the endocranial and exocranial NC in terms of the sides (p > 0.05). The length of the endocranial VC was greater on the right than on the left side. The right exocranial VC was wider than the left exocranial VC. However, the widths and lengths of the endocranial and exocranial NC showed no statistically significant difference between the sides (p > 0.05). CONCLUSION: The right-sided dominance of JF observed in this study was attributed to the length of endocranial VC and the width of exocranial VC.

Radiologic analysis of the location, shape and size of the external aperture of the carotid canal in children.

OBJECTIVES: This retrospective computed tomography (CT) study was aimed to assess the growth dynamic of the external aperture of the carotid canal (EACC) in children aged between 1 and 20 years. METHODS: Two hundred patients (sex 100 females/100 males, average age 10.50 ± 5.77 years) with good head CT image quality were included in this study. CT images of the patients were used to obtain data related to the location, shape and dimension of EACC. RESULTS: EACC shapes were identified as oval shaped, round shaped, and tear-drop shaped in 58.3% (233 sides), 24% (96 sides) and 17.8% (71 sides), respectively. EACC length, disEACC-MSP (distance between EACC and midsagittal plane), and EACC width did not change from the prepubescence period; while, the disEACC-SC (distance between EACC and supramastoid crest) seemed to reach adult size in the postpubescence period. Linear functions for EACC length and width were calculated as: y = 5.453 + 0.091 × years, and y = 5.398 + 0.059 × years, respectively. CONCLUSION: The regression equations of the measured parameters representing the growth dynamic of EACC in children can be helpful to estimate its size, location and angulation, which suggest that the dimension and distances to certain anatomical landmarks seemed to reach adult size in different developmental periods. In this context, the findings of this study may seem to emphasize the importance of preoperative radiological evaluation on skull base, related to EACC, for multidisciplinary surgeon teams during childhood surgeries in terms of patients' positioning, and the selection of appropriate surgical approach.

Fetal Anatomy of the Optic Strut and Prechiasmatic Sulcus with a Clinical Perspective.

OBJECTIVE: The main objective of the study was to show the morphologic features of optic strut (OS) and prechiasmatic sulcus (PS) in the fetal skull base with a surgical anatomical perspective. METHODS: Twenty-three fetal cadavers (9 female, 14 male) with an average age of 21.70 ± 3.12 (range: 16-28) weeks of gestation in the inventory of the Anatomy Department were included in the study. Measurements were made with a digital image analysis software and goniometer. RESULTS: The sulcal length, interoptic distance, planum length, and sulcal angle were detected as follows: 3.91 ± 0.74 mm, 6.88 ± 1.04 mm, 6.55 ± 1.51 mm, and 24.52 ± 9.51°, respectively. Considering the location of the posteromedial margin of OS according to PS, OS was identified as the sulcal in 56.5% (13 cases), postsulcal in 30.4% (7 cases), and asymmetric in 13% (3 cases). According to the sulcal length and angle, PS was identified as type 1 in 26.1% (6 cases), type 2 in 21.7% (5 cases), type 3 in 30.4% (7 cases), and type 4 in 21.7% (5 cases). CONCLUSIONS: Our findings suggest that the sulcal length and angle reach adult size in utero. Taking into account the fetal and the gathered adult measurements, the high percentage of steep angle compared to flat angle show that after birth, PS become more flat, probably depending on the variations of the sphenoid sinus pneumatization. Thus, more studies conducted on the alterations in PS and OS types relative to the pneumatization are needed in terms of patient positioning, selection of appropriate surgical approach, and intraoperative decision-making.

Growth dynamic of the geniculate ganglion in children: a retrospective computed tomography study.

PURPOSE: The main aim of this retrospective computed tomography (CT) study was to examine the morphometric development of the geniculate ganglion (GG) in children aged between 1 and 18 years for surgical approaches. METHODS: This study was placed on 41 patients (20 females and 21 males) including cochlear implantation cases aged from one to 18 (at mean, 6.44 ± 5.79) years. All the measurements belonging to the length, width and area of GG were performed with a CT scanner. RESULTS: The morphometric values of GG were not different in terms of sex or side, statistically (p > 0.05). The length (p = 0.155) of GG was not correlated with the increasing ages from one to 18 years; however, its area (p < 0.001) and width (p = 0.003) were found to be increased in the childhood period. Linear functions for the length, width and area of GG were calculated as y = 2.028 + 0.011 × age (years), y = 1.496 + 0.014 × age (years), and y = 3.239 + 0.035 × Age (years), respectively. The dehiscence of GG was found in 22 (26.8%) out of 82 temporal bones. CONCLUSION: Our data suggested that the area and width of GG were progressively increasing with age in the childhood period. The calculated formula representing the growth dynamic of GG in children and the incidence of the presence of the dehiscent GG can be useful for radiologists and otologists to estimate its size and to avoid iatrogenic injury during early childhood surgeries.

Radioanatomic Assessment of the Geniculate Ganglion Dehiscence and Dimension: A Cadaveric Study.

OBJECTIVE: The main aim of this study placed on cadavers was to compare the data related to geniculate ganglion (GG) dehiscence and dimension obtained from computed tomography (CT) with dissection values. METHODS: This study was conducted on 20 temporal bones obtained from 10 cadavers (4 female, 6 male) aged between 45 and 92 (71.50 ± 15.98) years. All the measurements related to GG dimension were performed with a CT scanner and microdissection. RESULTS: The size of GG including its area, length, and width did not show statistically significant differences in terms of sex, side, and assessment method (CT and cadaveric dissections). The dehiscent GG was observed in 6 (30%) and 5 (25%) out of 20 temporal bones in CT and cadaveric dissections, respectively. The presence and absence of GG dehiscence in CT and dissection were similar in 75%. CONCLUSIONS: Our findings based on dissection data suggest that radiologic evaluation of dehiscent GG detection might be erroneous by 25%, which highlights that surgeons should be careful when lifting the dura to prevent GG injury during middle cranial fossa surgical approaches. On the other hand, there was no statistical difference between CT and dissection measurements related to GG dimension.

The Comparison of the Right and Left Sigmoid Sinus Cross-Sectional Areas in Fetal Period and the Factors Affecting the Venous Dominance.

OBJECTIVES: Skull base is an important and a challenging area for surgeons. Success in skull base surgery depends on various factors such as pre-operative evaluation, appropriate surgical technique, anesthesia duration, intraoperative neuromonitorization and wound care. MATERIALS AND METHODS: This study was performed in the Anatomy dissection laboratory of M.U. Medical Faculty (Ethical committee approval number 2010-103). Twelve fetuses between 17-33 gestational weeks fixed with formaldehyde were enrolled to the study. RESULTS: This study was planned to investigate the cross sectional areas of the sigmoid sinus in three levels to compare the right-left sides and the probable relationship among the levels in fetuses to further delineate the developmental factors on jugular foramen asymmetry. The cross-sectional measurements of sigmoid sinus lumen were done on 3 levels which are described as A1 level; sinodural angle, A2 level; the midpoint between the sinodural angle and endocranial orifice and A3 level as the entrance (endo-cranial orifice) of the jugular foramen. There is a strong positive correlation between left (L) A1 and L A2 and also the same for L A1 and right (R) A2. These strong and positive correlations are all valid between L A2-L A3, L A2-R A2, L A2-R A3, L A3-R A3, R A1-R A2. CONCLUSION: Multicenter studies would be beneficial to investigate the topic with greater number of fetuses also on the different regions for genetic differences.

Morphometric Features of the Latissimus Dorsi Muscle in Fetal Cadavers With Meningomyelocele for Prenatal Surgery.

PURPOSE: Latissimus dorsi (LD) flaps are frequently used in the prenatal meningomyelocele (MMC) repairs; on that basis, this study aims to reveal the morphometric features of LD, thoracodorsal artery (TDA) and nerve (TDN) in fetal cadavers with MMC defects, with an anatomical perspective. METHODS: The study was conducted on 7 formalin-fixed human fetal cadavers (4 males and 3 females) with MMC defects, aged from 18 to 27 weeks of gestation. The size of LD, TDA, and TDN including their area, length, and width were measured by a digital caliper and digital image analysis software. Our direct measurements were compared with the corresponding estimations of a previous study in the literature which provides regression formulae based on gestational age. RESULTS: The fetal cadavers with MMC had bilateral LD. No significant differences were found in the numerical data of anatomical structures between the sides or the sexes. LD size (ie, area, length and width) was approximately 3% to 10% smaller in the fetuses with MMC defects than that of the normal fetuses. Unilateral LD flap in a 22-week-old fetus with a large MMC was evaluated as insufficient to close the defects. CONCLUSION: Ten percent shrinkage in the area of LD might be too critical to be disregarded by surgeons during the closure of MMC defects. The dimensional findings about LD (area, length, and width) may be helpful in planning of LD flap harvesting for the repairs of MMC.

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.

Morphometric Assessment of the Carotid Foramen for Lateral Surgical Approach.

OBJECTIVES: This study aimed to compare the right and left sides of the carotid foramen (CF) to determine its precise location according to certain anatomical landmarks. MATERIALS AND METHODS: Twenty human dry skulls were included in the study. A digital caliper and a digital image analysis software were used to obtain direct anatomical numerical values. Then, the same parameters on dry skulls were assessed with computed tomography (CT). RESULTS: CF was found to be round shaped (62.5%), oval shaped (32.5%), and tear-drop shaped (5%). In all cases, the position of CF was seen as just postero-laterally of the foramen lacerum. According to the jugular foramen, CF was seen to be anterior in 85% and antero-medial in 15% of the cases. Regarding the morphometric values of the surface area, the length and width of CF were observed to be 37.86±11.24 mm2, 8.02±1.09 mm, and 6.86±0.90 mm at direct anatomical measurements and 39.69±10.07 mm2, 7.89±1.14 mm, and 6.41±0.90 mm at CT, respectively. The angles between the supramastoid crest-CF-zygoma root and the supramastoid crest-CF-mastoid process were determined as 37.11±6.87º and 42.22±6.40º at direct anatomical measurements and 36.59±4.94º and 43.71±4.55º at CT, respectively. CONCLUSION: A significant difference in sides was not observed in relation with the numerical data of CF obtained from CT or from direct anatomical measurements of dry skulls. Moreover, a significant difference was not found between radiological and direct anatomical measurements. Therefore, precise radiological assessment of this region by an experienced neuroradiologist may be assumed as a fundamental need for successful surgeries of the skull base, in addition to thorough anatomical knowledge of neurootologists and neurosurgeons.

Morphometric properties of the facial canal in children: A retrospective computed tomography study.

PURPOSE: The main objective of the study was to examine the morphometric development of the facial canal in temporal bones aged from one to 18 years for pediatric otosurgeons and neurosurgeons. METHODS: The study was performed on 41 patients including cochlear implantation cases (20 females and 21 males) with a mean age of 6.44 ±â€¯5.79 years. All the measurements belonging to the facial canal including the length, width and angles of its segments were performed using the data of computed tomography assessment. RESULTS: The numerical data of the facial canal segments were not different in terms of sexes or sides, statistically (p > 0.05). The width of the labyrinthine segment (p = 0.145), the length of the tympanic segment (p = 0.555), the first (p = 0.067) and second (p = 0.060) genu angles seemed to reach adult size at two years of age. In addition, the length of the labyrinthine segment (p = 0.064) and the width of the mastoid segment (p = 0.264) seemed to attain adult size at four years, while the width of the meatal foramen (p = 0.264) seemed to arrive adult size at seven years. However, the length of the mastoid segment and the width of the tympanic segment were developing independently of increasing age between 1 and 18 years. CONCLUSION: Our data suggested that, contrary to the general acceptance in the literature, the dimension of the facial canal segments show remarkable changes during the transition from intrauterine life to adult life. The regression equations representing the facial canal growth dynamic in children may be useful for otosurgeons to estimate the size of its segments and to prevent iatrogenic injury during early childhood surgeries such as cochlear implantation.

Natural history of neuromodulation devices and therapies: a patient-centered survival analysis.

OBJECTIVE: Despite rapid development and expansion of neuromodulation technologies, knowledge about device and/or therapy durability remains limited. The aim of this study was to evaluate the long-term rate of hardware and therapeutic failure of implanted devices for several neuromodulation therapies. METHODS: The authors performed a retrospective analysis of patients' device and therapy survival data (Kaplan-Meier survival analysis) for deep brain stimulation (DBS), vagus nerve stimulation (VNS), and spinal cord stimulation (SCS) at a single institution (years 1994-2015). RESULTS: During the study period, 450 patients underwent DBS, 383 VNS, and 128 SCS. For DBS, the 5- and 10-year initial device survival was 87% and 73%, respectively, and therapy survival was 96% and 91%, respectively. For VNS, the 5- and 10-year initial device survival was 90% and 70%, respectively, and therapy survival was 99% and 97%, respectively. For SCS, the 5- and 10-year initial device survival was 50% and 34%, respectively, and therapy survival was 74% and 56%, respectively. The average initial device survival for DBS, VNS, and SCS was 14 years, 14 years, and 8 years while mean therapy survival was 18 years, 18 years, and 12.5 years, respectively. CONCLUSIONS: The authors report, for the first time, comparative device and therapy survival rates out to 15 years for large cohorts of DBS, VNS, and SCS patients. Their results demonstrate higher device and therapy survival rates for DBS and VNS than for SCS. Hardware failures were more common among SCS patients, which may have played a role in the discontinuation of therapy. Higher therapy survival than device survival across all modalities indicates continued therapeutic benefit beyond initial device failures, which is important to emphasize when counseling patients.

Rare Cause of Acute Tetraplegia and Respiratory Arrest: Cervicomedullary Neuroenteric Cyst in a Child: Case Report.

BACKGROUND: Neuroenteric cysts (NCs) are benign, rare congenital lesions which are most commonly found in the lower cervical and upper thoracic segments. Even though these are benign lesions, it may present with fatal neurologic deterioration particularly in pediatric patients. CASE REPORT: We here report a 16-year-old boy who has unique manifestation with acute tetraplegia and respiratory arrest in emergency room. According to English literature, this is the first case of cervicomedullary intradural neuroenteric cyst which causes acute tetraplegia and respiratory arrest in a child. CONCLUSION: The NCs can be manifested with unpredictable, life threating clinical presentation. The exact pathophysiology of an acute neurological deterioration is still unclear, however prolonged latent period with minor symptom should be considered carefully in child population.

Multiple muscular abnormalities in a fetal cadaver with CHARGE syndrome.

The CHARGE syndrome characterized by coloboma, heart defects, atresia of the choanae, retarded growth, genitourinary hypoplasia, and ear anomalies is one of the rare syndromes. Although certain clinical issues (scapular winging, sloping shoulder, Sprengel's deformity, kyphosis and scoliosis) which could be related to abnormalities in musculoskeletal structures of the neck and shoulder have been identified in CHARGE syndrome, data on details of muscle anomalies seem to be quite limited in the literature. In this case report, bilateral multiple muscular abnormalities (agenesis of the trapezius, presence of the rhombo-atloid muscle, and presence of the bipartite rhomboid minor with superficial and deep parts) was presented in a fetus cadaver with atypical CHARGE syndrome to attract the attention of clinicians for definitive diagnoses and surgical reconstruction of the shoulders deformity such as scapular winging and Sprengel's deformity. By considering the previous studies, we propose that the absence of the trapezius, as well as the other muscle abnormalities around the neck and shoulder, should be revised as being a component of CHARGE syndrome.