OBJECTIVETo determine the optimal drill area on the footplate with the 3D measurements of the stapes and the vestibular end organs.

METHODSFour temporal bones were extracted from the fresh cadavers and undecalcified polymer-embedded. After serially sectioning, image processing and the 3D precisely reconstruction, a local Cartesian coordinates was established in which the tympanic surface of the footplate was supposed to be XY plane and the Z coordinate axis passed through the central point of the footplate and was vertical to the XY plane. The configurations of the utricle and saccule were delineated quantitatively, and then any distance between one point on the surface of the footplate and another point on the surface of the utricle or saccule and its orientation can be measured.

RESULTSThere was a "V" shaped cleft between the utricle and the saccule. The angle of the" V" shaped cleft was 50.31 +/- 19.90 (17.00 - 68.00) degrees. The apex of the cleft directed anterosuperiorly and approached the footplate center, while beneath the posteroinferior part of the footplate was an open and deep area. The vertical distance from the center point of the footplate to the vestibular end organs was (2.20 +/- 0.548) mm, the maximum of 3.0 mm and the minimum of 1.6 mm.

CONCLUSIONSThe posterior and inferior quadrant of the footplate may be the optimal drill area for the fenestra.

Adult ; Humans ; Imaging, Three-Dimensional ; Saccule and Utricle ; anatomy & histology ; Stapes ; anatomy & histology ; Temporal Bone ; anatomy & histology

OBJECTIVE: Through the observation and the measurements of the significant anatomical landmark the lateral skull base, to provide anatomical data of clinical location and navigation for surgery at the lateral skull base. METHOD: Significant anatomical landmarks of twenty adult cadaveric heads (40 sides) fixed in 10% formaldehyde and 20 operation cases (20 sides) had been observed and measured. Lateral skull bases of cadaveric heads were numbered from 1st to 40th, while the operation cases were numbered from 1st to 20th. RESULT: The anatomical data was achieved by measuring related anatomical landmark as follows: the distances between the significant landmark of the lateral skull base and the pars neuraxis, vein of the jugular foramen; the areas of trautmann triangle; post labyrinths triangle and the superficial triangle of processus mastoideus; the maximal distance of initiative displacement of facial nerve in the lateral skull base operations. CONCLUSION The data measured at lateral skull base could effectively help operators not only to enlarge the field of vision in operations with security and to avoid the damagement of the important blood vessel and nerves, but also to retain the function of the facial nerve to the utmost.
Adult ; Female ; Humans ; Male ; Mastoid ; anatomy & histology ; Skull Base ; anatomy & histology ; Temporal Bone ; anatomy & histology

OBJECTIVE: To observe anatomic structure of jugular foramen region by endoscope, to provide anatomic data for avoiding damnification in the surgery. METHOD: We performed the retrolabyrinthine and retrosigmoid endoscopic surgery on 8 fomalin-fixed adult cadaver specimens and observed the structures of jugular foramen by endoscope and compared the different surgeries at the same time. We excised the calvarium and cereburm and exposured and observed the nerves and vessels. Moreover we measured the the distance from internal accoustic pore to glossopharyngeal and analyse the data by SPSS. RESULT: All retrolabyrinthine endoscopic surgeries were performed successfully. Only 4 postsigmoid endoscopic surgeries were performed without damage of cerebellum which is the major obstacles. The distance from internal accoustic pore to glossopharyngeal was(8.26 ± 1.05) mm. About half of posterior inferior cerebellar arteries located to inboard of nerves. CONCLUSION The jugular foramen region endoscopic surgery can be performed successfully by retrolabyrinthine. The "lockhole" technology by retrosigmoid is more difficult for blocking of cerebella. The internal acoustic porus is a fixed structure of the cerebellopontine angleand a perfect landmark to the surgery.
Adult ; Cadaver ; Endoscopy ; Foramen Magnum ; anatomy & histology ; Humans ; Jugular Veins ; anatomy & histology ; Temporal Bone ; anatomy & histology

OBJECTIVETo study the bone anatomic structure of the temporal bone region and provide reference in implant surgery in this region.

METHODSManual quantitative measurements of the bone structure were performed in 73 skull specimens (38 from male and 35 from female).

RESULTSIn the area of 8:00-11:00 (right ear) and 16-22 mm from center of the external auditory canal in the temporal bone region, the minimum bone thickness is as follows: 11:00: 6.77 mm in male, 5.18 mm in female; 10:00: 8.60 mm in male, 6.77 mm in female; 9:00: 9.85 mm in male, 7.30 mm in female; 8:00: 14.50 mm in male, 10.80 mm in female.

CONCLUSION(1) In the temporal bone region, the area of 8:00-11:00 (right ear) and 16-22 mm from center of the external auditory canal offers sufficient bone for implants. The length of implants should be as follows: 11:00: 4-5 mm in male, 3-4 mm in female; 10:00: 4-7 mm in male, 4-5 mm in female; 9:00: 4-8 mm in male, 4-6 mm in female; 8:00: 4-12 mm in male, 4-8 mm in female. (2) Towards the external auditory canal and from 12:00 to 11:00, 10:00 to 8:00, the bone became thicker, so, if no ample bone is available in the initial site, the location should be shifted anti-clockwise in right side (clockwise in left side) and closer to the external auditory canal. (3) The differences between male and female are statistically significant in the temporal bone region, so they should be treated distinguishingly during the clinical practices.

Ear Canal ; anatomy & histology ; Female ; Humans ; Male ; Prostheses and Implants ; Temporal Bone ; anatomy & histology

BACKGROUNDThe temporal bone has the most complicated anatomic feature among the whole human body, which always challenges otolaryngologists. This study was to study three-dimensional (3D) morphology of the temporal bone and the ear by means of a computer image processing technique, for the purpose of providing a 3D image to help in pathological, diagnostic and surgical procedures.

METHODSForty sets of temporal bone celloidin serial sections with reference points were prepared and the contours of selected structures and reference points were entered into a graphics programme. The technique of computer-aided 3D reconstruction was applied to obtain 3D images and parameters of the temporal bones and the ears. Stereo views of the ossicles (n = 5), the facial nerves (n = 11), the posterior tympanic sinuses (n = 11), the posterior ampullary nerves (n = 4), the endolymphatic ducts and sacs (n = 5), and the bony and membranous labyrinth (n = 1) were reconstructed.

RESULTSThree-dimensional images, including the cochlea, the ossicles, the nerves, the tendons and the endolymphatic fluid system in the temporal bone, were obtained. Stereo picture pairs and 3D parameters of spatial dimensions, angle and volume for these reconstructed structures were calculated. The arrangement of the ossicles, spatial relationship of the bony and membranous labyrinth, the whole course of the facial nerves, the endolymphatic sac and posterior tympanic cavity were clearly observable. Stereo picture pairs made the spatial relationships among the above-mentioned structures much clearer. The operation of the posterior ampullary nerve transection was designed and simulated on the graphic computer based on 3D anatomic investigations.

CONCLUSIONThe technique of computer-aided 3D reconstruction provides a new tool to observe the morphology of the temporal bone and thus may allow design and study of new surgical approaches.

Ear ; anatomy & histology ; Facial Nerve ; anatomy & histology ; Humans ; Image Processing, Computer-Assisted ; Imaging, Three-Dimensional ; Temporal Bone ; anatomy & histology

OBJECTIVE: To provide the anatomic data for the correlated otologic microsurgery by the microdissection of temporal bone through facial recess approach. METHOD: Sixteen human temporal bones of eight adult cadaveric heads were dissected under surgical microscope through facial recess approach, and the relative anatomic structures were observed and measured, such as the bony entrance of facial recess approach, facial nerve, stapes, round window, round window niche, pyramidal eminence, cochleariform process, etc. The data were analyzed statistically. RESULT: The width of the bony entrance of facial recess approach was (2.94 +/- 0.32) mm, the height was (8.83 +/- 0.84) mm, the depth was (3.51 +/- 0.17) mm. The distances from stapes to tympanic segment of facial nerve, mastoid segment of facial nerve, round window, cochleariform process and anterior ligament of malleus were (1.38 +/- 0.21) mm, (6.94 +/- 0.47) mm, (3.60 +/- 0.55)mm, (2.23 +/- 0.33)mm, (4.93 +/- 0.61) mm, respectively. The distances from pyramidal eminence to tympanic segment of facial nerve, mastoid segment of facial nerve, round window, round window niche and cochleariform process were (1.05 +/- 0.09) mm, (5.63 +/- 0.41) mm, (3.01 +/- 0.34) mm, (3.29 +/- 0.44) mm, (4.13 +/- 0.51) mm, respectively. The distances from round window to cochleariform process and tympanic segment of facial nerve were (5.11 +/- 0.61) mm and (3.97 +/- 0.61) mm. The distances from round window niche to tympanic segment of facial nerve and mastoid segment of facial nerve were (4.13 +/- 0.38) mm and (7.28 +/- 0.29) mm. CONCLUSION The facial recess approach played an important role in modern otologic microsurgery. The position of anatomical structure was constant relatively, including short crus of incus, stapes, pyramidal eminence and cochleariform process, etc. These could be used as reference marks for otologic microsurgery.
Adult ; Ear, Middle ; anatomy & histology ; surgery ; Facial Nerve ; anatomy & histology ; surgery ; Humans ; Microsurgery ; Round Window, Ear ; anatomy & histology ; surgery ; Stapes ; anatomy & histology ; Temporal Bone ; anatomy & histology ; surgery

OBJECTIVE: To provide anatomic data for cochlear implantation, and to find the method of locating lamina spiralis (LS) on the surface of promontory. METHOD: Microanatomical study was carried out on 30 sides of human temporal bones by observing and measuring lamina spiralis below promontory, including its location, course and adjacent structures. RESULT: (1) The basal turn of lamina spiralis below promontory can be divided into three segments: the hook segment (1.52 +/- 0.16) mm, the anteroinferior round window segment (3.83 +/- 0.37) mm and the forwarding segment (2.70 +/- 0.36) mm by two hinge points of which one was located at anterior of the junction of superior margin and anterior border of RW, and the other was located at anteroinferior of the round window; (2) The plane of round window anteroinferior segment of LS lay (51.00 +/- 5.97) degrees anteroinferior to horizontal segment of the facial nerve and comparative permanently meet posterior margin of'stapes head. Made posterior margin of stapes head as a fixation point and draw a line on promontory lay (51.00 +/- 45.97) degrees anteroinferior to horizontal segment of the facial nerve. This line can be thought as the projection of anteroinferior round window segment of LS on promontory; (3) The width of scala tympani at cochleostomy site on promontory: width of scala tympani at midpoint of superior margin of round window was (0.36 +/- 0.06) mm; width of scala tympani at midpoint of anterior border of round window was (0.97 +/- 0.14) mm; width of scala tympani at 3 mm point of anteroinferior round window segment was (1.24 +/- 0.21) mm. CONCLUSION (1) The basal turn lamina spiralis below promontory can be divided into three segments (the hook segment, the anteroinferior round window segment and the forwarding segment) by two hinge points; (2) The projection of anteroinferior round window segment of LS and the features exhibited in its course provide reference for locating the basal turn scala tympani and offer reliable anatomical basis for minimal invasive intervention during cochlear implantation.
Adult ; Cochlear Implantation ; methods ; Facial Nerve ; anatomy & histology ; surgery ; Humans ; Round Window, Ear ; anatomy & histology ; surgery ; Scala Tympani ; anatomy & histology ; surgery ; Temporal Bone ; anatomy & histology ; surgery

OBJECTIVETo study the exposure of suboccipital far-lateral approach and postauricular transtemporal approach to the jugular foramen region based on quantitative measurements, and provide reliable anatomic data for selecting surgical approach individually and protecting the function of important structures.

METHODSThe complete approach of the suboccipital far-lateral approach and the postauricular transtemporal approach were reproduced in twelve (twenty-four sides) head-neck specimens of adults be fixed in 10% formalin. The exposure area to the jugular foramen region was obtained using a stereotactic device, and the length of exposure of the clivus and the trigeminal nerve were measured using a vernier caliper.

RESULTSIn the suboccipital far-lateral approach, the significant increase in exposure was noted after removal of the jugular process and partial resection of occipital condyle. In the postauricular transtemporal approach, the exposure increased significantly after complete retrolabyrinthine approach, partial labyrinthectomy and transcochlear approach.

CONCLUSIONSResection of jugular process is the key to expose the jugular foramen through the far-lateral approach. The infralabyrinthine approach and the partial labyrinthectomy approach are ideal approaches to expose the jugular foramen region laterally.

Adult ; Cadaver ; Craniotomy ; methods ; Humans ; Jugular Veins ; Occipital Bone ; anatomy & histology ; innervation ; surgery ; Skull Base ; anatomy & histology ; innervation ; surgery ; Temporal Bone ; anatomy & histology ; innervation ; surgery

Presbycusis is defined as the natural hearing loss accompanying aging, caused by degenerative changes in the inner ear. The etiology of presbycusis is uncertain. However, it would appear that a complex genetic cause is most likely. The determinants of mastoid size continue to be controversial. One of the pneumatization theories is the hereditary theory. In this study, the possible relationship between presbycusis and the extent of mastoid pneumatization was investigated. This study was carried out on 21 patients with presbycusis and 21 normal subjects of similar ages. The pneumatized volume was measured by computerized tomography. The temporal bone was scanned at 2 mm thickness intervals. Exposure (kV 130, mA105). The scan plane was parallel to the orbitomeatal line and the CT images covered the entire mastoid region. The average mastoid pneumatization in presbycusis group was 6.08 +/- 2.52 cm3 in the right ear and 6.19 +/- 2.93 cm3 in the left ear. However, in the control group it was 4.69 +/- 3.17 cm3 in the right ear (p=0.12) and 5.10 +/- 3.49 cm3 in the left ear (p=0.28). No significant difference was found between the presbycusis patients and normal subjects in terms of the volume of mastoid pneumatization.
Aged ; Hearing Tests ; Human ; Mastoid/*anatomy & histology/radiography ; Middle Aged ; Presbycusis/*etiology/genetics/radiography ; Temporal Bone/anatomy & histology/radiography

OBJECTIVETo study the anatomy of mandibular bone flap pedicled with temporal muscle for midfacial bone defects.

METHODSThe shape and blood supply of the temporal muscle and mandibular ramus, as well as their relationship, were observed and measured in 30 sides of adult head specimens.

RESULTSThe temporal muscle has a fan-shaped main portion, then is scattered into three bundles as anterolateral, anteromedial, posterior bundles, which end respectively at anterior border of ramus, the temporal ridge and posterior portion of coronoid process. Then the muscle goes downward until it reaches the distal side of the third medial surface molar and attaches the 3/4 of medial surface of anterior portion of ramus. The blood supply of temporal muscle includes the medial temporal artery with external diameter of (0.76 +/- 0.20) mm, the anterior deep temporal arteries with external diameter of (0.79 +/- 0.21) mm, posterior deep temporal arteries with external diameter of (0.98 +/- 0.64) mm, the accessory deep temporal artery formed by many little branches. The anterior part of ramus is supplied by the periosteal arteries and the bony perforator of the deep temporal arteries. Rectangular ramus of mandible was divided into anterior portion and posterior portion by the line linking the lowest point of mandibular notch, mandibular foramen and mandibular canal. Anterior portion can supply a bone flap with a size of (46.67 +/- 6.85) mm x (17.98 +/- 2.64) mm x (11.49 +/- 0.99) mm.

CONCLUSIONSThe mandibular bone flap pedicled with temporal muscle has a reliable blood supply and abundant bone volume. It is feasible to design a mandibular bone flap pedicled with temporal muscle for midfacial bone defect.

Adult ; Bone Transplantation ; Female ; Humans ; Male ; Mandible ; anatomy & histology ; surgery ; Surgical Flaps ; Temporal Muscle ; anatomy & histology ; blood supply ; innervation