Microsurgical endoscopy-assisted presigmoid retrolabyrinthine approach with mastoid bone drilling: an anatomical laboratory investigation.

PURPOSE: This study aims to evaluate the applicability of the endoscopy-assisted presigmoid retrolabyrinthine approach, advantages, disadvantages, and the applicability of surgery with pre-op radiological parameters; identify important landmarks; and to reveal their relationships with important structures in the surgical field with objective data. Also, we aim to improve the surgical technique for increasing reachable anatomic structure. METHODS: Mastoid drilling and endoscopy-assisted presigmoid retrolabyrinthine approach were performed and endoscopic instruments were used to obtain the three-dimensional pictures. Computed tomography images were evaluated to correlate to the anatomic data. RESULTS: In terms of pre-operative radiological evaluation of the applicability of the presigmoid approach were investigated with selected radiological parameters. The endoscopy-assisted presigmoid retrolabyrinthine approach applied to cadavers the relationship, distances between important anatomical landmarks, and anatomical structures in the surgical field recorded. The anatomical structures that could reach with the application of the procedure were recorded. The relationship between pre-operative measured radiological parameters and surgical results was evaluated with objective data. Additional combinations to improve this surgical method discussed and the results of our combination were recorded with photographs. CONCLUSION: Although the presigmoid retrolabyrinthine approach has facilitated with the assistance of endoscope, it has observed that there are still some difficulties, and it has been concluded that the radiological parameters are useful in evaluating the applicability of this surgery. It observed that this surgery can be performed more effectively with combinations.

Posterior Wall Defect of Sacrum: An Anatomical Study of Sacral Spina Bifida.

AIM: To investigate the incidence, types, morphological and morphometric properties of spina bifida on dry sacral bones. MATERIAL AND METHODS: 110 dry adult sacrums gathered from the bone collections of the Laboratory of the Anatomy Department of Dokuz Eylul University School of Medicine were examined. The parameters analysed were: 1) results of parameters related to the posterior sacral wall; 2) classification and rate of the closure defects; 3) classification of the top sacral vertebrae according to the shape of its superior surface; 4) presence of sacralisation and lumbalisation among sacrums with dorsal wall defects; 5) vertebral levels of apex of the sacral hiatus; and 6) vertebral levels of closure defects of the sacrums. RESULTS: We determined 22/110 (20%) sacrums demonstrated spina bifida. Of these 22 sacrums, 4 (18.18%) showed complete and 18 (81.82%) showed incomplete spina bifida. We noted the coexistence of spina bifida with sacralisation (6/22 [27.27%]) and lumbalisation (5/22 [22.73%]). The types of defects were described and grouped as ?V? (Type 1), inverse ?V? (Type 2), window (Type 3), foramen (hole) (Type 4), sand watch (Type 5), narrow linear (Type 6), wide linear (Type 7), and bridged (Type 8). The shape of upper surfaces of the sacrums with spina bifida was grouped as: cavity (20/22, 90.9%), hump (1/22, 4.5%), and flat (1/22, 4.5%). CONCLUSION: A precise definition of the anatomical variations of sacrums is essential for surgeons, particularly when operating using endoscopic techniques and for anaesthesiologists applying caudal epidural block.

Endoscopic endonasal transclival approach to the ventral brainstem: Radiologic, anatomic feasibility and nuances, surgical limitations and future directions.

The endoscopic endonasal transclival approach (EETA) is less invasive than traditional open approaches; however, there is currently limited data on the pre-operative features that may predict success of the EETA. Surgical landmarks and exposure of the EETA and expanded EETA are assessed. We retrospectively measured multiple anatomic features in 154 adult dry skulls, 22 C1 and C2 dry bone vertebrae, and 500 paranasal sinus computed tomography (CT) scans. We also dissected 13 formalin-fixed, silicone-injected adult cadaveric heads. Relevant qualitative and quantitative data were obtained with CT (n = 10) and cadaveric dissection (n = 13). They are expressed as mean (SD), as appropriate and compared with unpaired t tests. Categorical variables were compared with χ2 tests. We determined the prevalence of clival and sphenoid sinus anatomic variations and assessed potential exposure of the craniovertebral region, based on the relative position of the nasal bone tip, posterior point of the hard palate, and their relation to the position of C1 and C2. Depending on anatomic features, EETA should allow visualization of the ventral brainstem. The mean (SD) dimensions of the surgical window for EETA were 43.2 (5.1) × 18.3 (1.1) mm, in the craniocaudad and horizontal dimensions, respectively. The craniocaudad dimension enlarged to 60.2 (4.7) mm with expanded EETA. The EETA allowed satisfactory exposure for odontoid and C1 anterior arch resection (expanded EETA) in all specimens, regardless of the orientation of the palate. The combination of preoperative radiographic assessment and intraoperative considerations allows safe and effective application and facilitate selection of the most appropriate approach.

Radiological and Surgical Anatomy of Ventral C1-C2 Complex.

AIM: To evaluate anatomical data of the bony structures during exploration of the C1-C2 complex. MATERIAL AND METHODS: This study included six formalin-fixed cadaveric head and neck specimens. Radiological images and anatomical measurements included: C1-C2 distance, bony distance between C1 anterior tubercle-nares and superior incisors, height of C1 anterior arch, and height and width of odontoid articular surface. RESULTS: The mean distance between C1 anterior tubercle-nares and superior incisors on maxilla were 96.16 ± 8.07 mm and 84.14 ± 9.16 mm, respectively. The mean height of C1 anterior arch was 13.89 mm. The meandistance between medial borders of right-left C1 lateral masses was 19.10 ± 1.80 mm. The mean distance between medial border of lateral midline on mass right and left sides were 9.43 ± 0.88 mm and 9.68 ± 0.97 mm, respectively. The mean height of C1 anterior arch at midline was 13.89 ± 2.48 mm, and the mean distance between ventral surface of anterior arch and ventral joint of odontoid at midline was 6.43 ± 1.29 mm. The anteroposterior, horizontal diameters of odontoid on its base were 12.12 ± 0.38 mm, and 11.12 ± 0.94 mm, respectively. The angles of transoral and transnasal approaches to C1 were 32.67 ± 4.59° and 32.00 ± 2.10°, respectively. CONCLUSION: A safe transoral or transnasal odontoidectomy requires accurate measurements and imaging regarding ventral C1-C2 relationships, distances of odontoid, lateral mass and midline.

Anatomical and Radiological Investigation of Dry Bone Adult Mandibles Having Impacted Third Molar Teeth.

OBJECTIVE: To investigate the incidence of the impacted mandibular third molars in dry bones adult mandibles. METHODS: The 198 dry bones adult mandibles gathered from the bone collections in Laboratory of the Anatomy Department of Dokuz Eylul University School of Medicine were macroscopically examined for the presence of impacted mandibular third molars. The genders of the adult bones were unknown. The adult mandibles having impacted third molars were photographed with Canon 400B (55 mm objective). The mandibles having impacted third molars were also radiographically examined with orthopantomography (a dental radiographic technique, kV 60, mA 2.0) in radiology unit of Faculty of Dentistry, Ege University. The impacted teeth were grouped according to their position and degree of impaction. RESULTS: The each of 2 of 198 adult mandibles (2/198; 1.01%) was having an impacted 3rd molar teeth. These 2 molar teeth were belonged to class 1, B and partially buried, vertically oriented. The first impacted 3rd molar teeth was located on the left side of the one mandible and the second one on the right side of the other mandible. CONCLUSION: The present study provides information about impacted mandibular 3rd molar in dry bones.

Surgical anatomy of neurovascular structures related to ventral C1-2 complex: an anatomical study.

OBJECTIVE: Transoral odontoidectomy and ventral C1-2 stabilization are important surgical procedures, performed to decompress ventral spinal cord, and to stabilize craniovertebral junction. These procedures require knowledge regarding surgical anatomy of neurovascular structures ventral to the C1-2 complex. The aim of this study is to evaluate the relationships between neurovascular structures and bony landmarks in ventral atlantoaxial complex. MATERIALS AND METHODS: This study was performed on six formaldehyde fixed cadaveric head and neck specimens. Relevant anatomical parameters, including distances from the midsagittal line to internal carotid arteries (ICA), vertebral arteries (VA), and hypoglossal nerves (HN), were measured using electronic calipers. RESULTS: The mean distance between ICA and midsagittal line was observed as 26.13 mm at the level of axis and 24.67 mm at the level of the atlas. The mean distance between VA and midsagittal line was observed as 15.38 mm at the level of axis and 26.54 mm at the level of the atlas. The mean distance between HN and midsagittal line was observed as 33.27 and 33.58 mm at the level of the atlas and axis, respectively. CONCLUSION: This study confirmed that ICA and HN proceeded ventrally or laterally along the lateral aspect of the C1 lateral mass; therefore, the area located ventrally along the medial components of the C1 lateral mass was the safe zone for anterior surgical approach.

Morphometric evaluation of the uncinate process and its importance in surgical approaches to the cervical spine: a cadaveric study.

INTRODUCTION: The uncinate process (UP) has an important role because of its relationship with the vertebral artery and spinal roots. Degenerative diseases cause osteophyte formation on the UP, leading to radiculopathy, myelopathy and vertebral vascular insufficiency, which may require surgical management. This study aimed to evaluate the morphometry of this region to shed light on the anatomy of the UP. METHODS: Morphometric data was obtained from 13 male formaldehyde-fixed cadavers. Direct measurements were obtained using a metal caliper. Computed tomography (CT) morphometry was performed with the cadavers in the supine position. RESULTS: Direct cadaveric measurements showed that the height of the UP increased from C3 (5.8 ± 1.0 mm) to C7 (6.6 ± 0.5 mm). On CT, the corresponding measurements were 5.9 ± 1.2 mm at C3 and 6.9 ± 0.6 mm at C7. The distance between the left and right apex of the UP from C3 to C7 also increased on both direct cadaveric and CT measurements (C3: 20.8 ± 1.0 mm and C7: 28.1 ± 2.4 mm vs. C3: 23.7 ± 3.4 mm and C7: 29.0 ± 3.0 mm, respectively). On CT, the distance between the UP and superior articular process at the C3 to C7 levels were 9.8 ± 1.7 mm, 7.9 ± 1.8 mm, 7.9 ± 1.6 mm, 7.8 ± 1.3 mm and 8.2 ± 1.7 mm, respectively. CONCLUSION: Direct cadaveric and CT measurements of the UP are useful for preoperative evaluation of the cervical spine and may lead to better surgical outcomes.

Morphometric evaluation of parasagittal venous anatomy for intracranial approaches: a cadaveric study.

AIM: Obstruction of superior sagittal sinus (SSS) and collateral bridging veins is a well-known reason of postoperative brain edema and brain infarct, however, morphometric anatomic studies done in the light of surgical landmarks aren't sufficient in number. Object of this study is to describe venous structures related to SSS with silicon injected cadaveric models. MATERIAL AND METHODS: This study was on 6 silicon injected cadaveric heads at Anatomy Department. Duramater was removed and veins on parasagittal area were examined. SSS morphology, veins draining into SSS, their size, number and distance were evaluated. RESULTS: Mean vein number draining into SSS is 2.9±1.5 at anterior to coronal suture (CS), between CS and vertex is 3.2±0.8, between vertex and lambdoid suture (LS) is 2.3±0.9, between LS and confluens sinuum 0.3±0.5. There was no statically difference between right and left sides (p=0.140, p > 0.05). Diameter of veins was 2.4±1.0 mm at anterior to CS, 3.0±1.2 mm at between CS and vertex, 2.4±0.7 mm at between vertex and LS, and 2.2±0.5 mm at between LS and confluens sinuum. CONCLUSION: Knowing details of anatomic structures of SSS and venous structures draining into it may protect the patients from many surgical complications. SSS and related structures with surgical landmarks are valuable for neurosurgeons.

The importance of the greater occipital nerve in the occipital and the suboccipital region for nerve blockade and surgical approaches--an anatomic study on cadavers.

OBJECTIVE: Greater occipital nerve (GON) blockade is an effective method for treatment of occipital neuralgias. Occipital neuralgia or neuropraxis of this region may be seen particularly as a result of compression of the GON. This study shows the relationship between the GON and its external bone landmarks, in order to prevent complications and to perform nerve blockades safely. The study also defines the points where the GON pierces the semispinalis capitis (SSC) and the trapezius, and where the GON passes the obliquus capitis inferior (OCI), and identifies bone landmarks for places where the GON may be entrapped. MATERIALS AND METHODS: In the laboratories of Dokuz Eylül University, Faculty of Medicine Department of Anatomy, 12 GON's belonging to male adult cadavers fixed in formaldehyde were dissected. Colored silicone was injected to all cadavers and then microdissections were performed under a dissection microscope. The lesser occipital nerve, the GON, the greater auricular nerve, and the occipital artery (OA) were dissected. All measurements were made with a 0.1mm sensitive calipometer. RESULTS: The GON's diameter at the point where the GON pierces the SSC was found to be 2.5±0.3 mm. The distance between the point where the GON pierces the SSC and the external occipital protuberance (EOP) was 53.6±5.0 mm. The distance between this point and the midline was 9.0±1.9 mm, the distance between this point and the intermastoid line was 11.5±3.9 mm and the distance between this point and the mastoid process was 65.5±5.9 mm. The distance between the midline and the point where the GON pierces the aponeurosis of trapezius (AT) was 47.9±8.0 mm, the distance between this point and the EOP was 15.1±7.0 mm, the distance between this point and the intermastoid line was 17.1±2.8 mm, and the distance between this point and the mastoid process was 59.4±2.3 mm. We measured the distance between the OA and the intermastoid line to be 8.5±6.1 mm vertically and 32.3±3.9 mm horizontally to the midline. CONCLUSION: In this study, we define the GON's route in the suboccipital and the occipital region where the nerve pierces the SSC and the AT and where blockade or surgery can be performed. These data will help the surgeon and clinician to avoid complications in this region.

Langerhans cell histiocytosis of the cervical spine in an adult: a case report.

We present a case of a 47-year-old-woman with a complaint of cervical pain with paresthetic appearance on her left arm. She was treated with analgetics. Further radiological evaluation because of the persistent pain revealed an osteolytic destruction of the fourth cervical vertebra. The patient underwent anterior cervical corpectomy with total excision of the tumor. Stabilization of the cervical spine was performed. Histology confirmed the diagnosis of Langerhans cell histiocytosis (LCH) of the cervical spine. This case report presents the histopathological evaluation, diagnostic work-up and the treatment procedures because of rarity of cervical spinal LCH cases in the literature.

Simulation of cerebrovascular circulation in the human cadaver for surgical neuroanatomy training.

OBJECTIVE: The current progress in diagnostic and screening methods and surgical equipment technologies facilitates the accessibility to numerous anatomic structures through various interventional approaches. Consequently, the exact knowledge of the anatomic locations of neurovascular structures and their interactions may ensure that the surgical intervention is planned in the most appropriate way and the structures are accessed with the least complication risk during the intervention. MATERIAL AND METHODS: A decapitated and formalin fixated whole-head of a male human cadaver kept for educational and research purposes in the Dokuz Eylul University Department of Anatomy was used in this study. Two separate reservoirs (for the arterial and the venous system) were connected to the Truno System 3 labeled perfusion pump. The reservoirs were filled with blue and red warm tap water. Colored tap water pumped on the right was emptied from the left. Continuous flow of the water in the closed-circuit arterial and venous systems was achieved. As the circulation was continuing, pterional craniotomy was performed and the dura mater was accessed and lifted under the Zeiss dissecting microscope. CONCLUSION: We believe that this model may contribute to neuroanatomy education and provide experience for the safe and ethical performance of surgical interventions during the intraoperative period.