Long Process Of Incus Research Articles

Clinical characteristics of the tympanic membrane retraction pocket

Development of the eardrum retraction pocket, as pathologic finding, depends on Eustachian tube dysfunction, onset of the middle ear infection and site of development of retraction on the eardrum. The study is aimed at: 1. Determining the incidence of eardrum retraction pocket and cholesteatoma within it, as well as at the degree of eardrum retraction; 2. Determining of association between eardrum retraction pocket and changes of the eardrum mucosa and pars tensa of the tympanic membrane; 3. Determining of onset and intensity of the bone destruction in eardrum retraction pocket; 4. Examining of Eustachian tube function based on time of mucocilliary transport according to the type of the eardrum retraction pocket. The study is based on the retrospective analysis of the results obtained from the patients treated at the Institute of Oto-Rhino-Laryngology and Maxillofacial Surgery, Clinical Centre of Serbia in Belgrade for the diagnosis of the chronic suppurative otitis who underwent otosurgical procedures during the six-year period, from 1996-2001. In our series of 540 patients subjected to otosurgical treatment, the incidence of the retraction pocket of the eardrum was 11.23%. Onset of more severe degree of eardrum retraction was most frequent in the attic. Cholesteatoma was detected in 82.2% of patients of the group with the attic-retraction pocket of the eardrum, as well as in 25% of patients of the group of tensa-sinus retraction pocket of the eardrum. Atrophic changes of the tympanic membrane pars tensa were detected in almost all tensa-sinus retraction pockets of the eardrum. Approximately one half of the attic-retraction pockets of the eardrum were accompanied by eardrum atrophy. Bone destruction of the auditory ossicles was limited to the long process of incus and superior structures of stapes. Time of the mucocilliary transport was significantly longer (p < 0.01) in attic-retraction pocket of the eardrum than in tensa-sinus retraction pocket of the eardrum, indicating significance of tube in development of attic-retraction pocket of the tympanic membrane. Reversible changes of the middle ear mucosa were evidenced in three quarters of the tensa-sinus retraction pockets of the eardrum indicating that inflammation is the major factor influencing onset of tensa-sinus retraction pocket of the eardrum.

Otological manifestations of a new familial polyostotic bone disorder

Fifty members of a family with a unique autosomal dominant bone disease were investigated. Nineteen of the family members were either known to have, or were strongly suspected of having the disease. All but one of these had a hearing loss which was conductive in the younger age group and mixed in the older members. The common finding in those who had middle ear surgery was replacement of the long process of incus by a fibrous band. The histological features were similar to those found in Paget's disease. The age of onset, distribution of lesions and radiographic findings, however, were not typical of this disorder.

Developmental study on the facial nerve and canal in man (author's transl)

The development of the facial nerve and its canal in the temporal bone was histologically investigated with serial sections in connection to the middle ear sugery.Materials used were 56 Japanese human embryos and fetuses aged from the 4th to the 23rd week (3.3 to 330mm in CR or CH length) that were stored in the Human Embryo Center for Teratological Studies of Kyoto University and Department of Otolaryngology, Okayama University Medical School. The results were as follows:1) The second arch epibranchial placode seemed to play an important role in the development of the geniculate ganglion.2) A trunk of the facial nerve, chorda tympani nerve and N. petrosus major accomplish before the ossicles appeared at the 6th week.3) The facial nerve was rapidly differentiated as the internal meatal, horizontal and vertical segments as with the development of the primordial stapes at the stage 17 and was gradually completed its normal running course by both the differentiation of the cartilagenous otic capsule and the pneumatization of the primitive tympanic cavity during the whole intra-uterine period.4) The development of the facial canal began as a sulcus on the canalicular division of the precartilagenous otic capsule at the stage 21. The formation of the tympanic boundary of the horizontal segment until the 22nd week of fetal life.5) Anson's hypothesis in which the head of malleus and the body of incus are made from Meckel's cartilage, and the handle of malleus and the long process of incus from Reichert's cartilage was supported.6) The rate of the thickness of the facial nerve to the diameter of the facial canal was large at the horizontal segment, but it was small at the vertical segment.

Study of the ear in anencephaly

The ears of 8 anencephalics were studied. No gross macroscopic abnormality in the development of the external, middle and internal ears were detected except that the internal auditory canals appeared more of a furrow with a bony ledge at its base. There was a malformed long process of incus with abnormal disposition of the round and oval windows below and behind the promontory in 2 ears. The reason for the association of ear anomalies in anencephaly is not yet clear and deserves further study.

Experimental Studies on the Stapedius Reflex Response and the Influence of Different Peri Lymphatic Pressures in Human Temporal Bones

An acoustically elicited stapedius muscle contraction in man has been shown to cause either an outward or an inward displacement of the tympanic membrane. Change of posture affects the displacement and three different patterns of movement have been found. In the present study experiments on human temporal bones were performed. A simulated muscle contraction was elicited by loading the stapedius muscle with weights, and the effect on the displacement of the tympanic membrane caused by applying different pressures to the perilymph was studied. In these experiments it was possible to reproduce all three patterns of stapedius reflex response which had been observed in man as caused by change of posture. The results thus indicate that the different responses found in man and induced by change of posture can be explained by a change in the perilymphatic pressure. It was also observed that the movement of the stapedial footplate caused by a simulated stapedius muscle contraction induced an increase in the volume of the perilymphatic space. Furthermore the movement of the tympanic membrane and the long process of incus always took the same direction.

Investigation on tomographic examinations of the temporal bone. Part I: tomography of the normal temporal bone, and its normal findings and variations (author's transl)

Tomograms including 127 frontal projections and 60 lateral projections from the normal temporal bones were examined and the following results were obtained.1. The ossicles were best visualized at a level of 1.7±5.0mm posterior to the porus acusticus externus on frontal projection, and at a level of 31.3±5.1mm medial to the auricle on lateral projection.2. On the frontal projection, all information, concerning the middle ear cleft was possible to be obtained from the four different planes; cochlear, transitional, vestibular and mastoid planes which were taken with the distance of 2.5mm between each cut.3. On the frontal projection with 4 different planes, the ossicles, spur, the horizontal portion of the facial nerve, the external auditory canal, the middle ear cavity, the cochlea, the vestibule, the internal auditory canal, the lateral and anterior semicircular canals, the mastoid antrum and mastoid cells were identified in all of the cases examined. However, the figue differences of each structure described above temporal bones were inevitable.The vestibular window was observed in 96% of the cases examined, mastoid tegmen in 94%, the pyramidal eminence in 90%, the Korner's septum in 97%. On the other hand, the tegmen of the attic was observed only in 48%, and the stapes in 14%, and then these figures did not seen to offer sufficient information for the diagnosis the middle ear cleft.4. In 60 tomograms with the laternal projection, one cut of the ossicular plane may include all information pertaining to the important structures in the middle ear cleft, The head and handle of malleus, the incus body, the long process of incus, tegmen tympani, the vertical portion of the facial canal were identified in 100% of the cases. With the slight difference in their shape. The anterior tympanic spine was observed in 85% and the mastoid clearly visualizd in 75% of the cases.

Clinical and embryological studies on middle ear malformations--observation on the joints of the ossicular chain (author's transl)

One hundred twenty four operated cases of middle ear malformation were reviewed with special reference to the ossicles. In the case of complete meatal atresia, the malleus and incus were fused in one mass, and the incudostapedial joint was separated due to maldeveloping long process of incus. In conductive-type malformation with normal or narrow ear canal, separation of the incudostapedial joint was seen more frequently than fused incus and malleus. As a supplemental study, a normal development of the ossiculer junction was investigated by means of phase contrast microscopy. In the nineth week human embryo, the cytoblastema of the malleus and incus were observed as a mass concentration of mesenchymal cells. It was confirmed that the malleus and incus were not differentiated at this stage. In the tenth week, the three ossicles were differentiated individually. At the incudomallear joint, the malleus and incus became pre-cartilaginous already and both ossicles were separated by a few rows of thin compressed fibroblastic cells. But the stapes was still an immature concentration of mesenchymal cells and there were five or six rows of mesenchymal cells on the surface of the incudostapedial joint. In the twelfth week, the malleus and incus became cartilaginous. The surface of the incudomallear joint was covered by _??_ row of compressed cells and the joint capsule was observed. At the incudostapedial joint, the head of the stapes became precartilaginous and five or six rows of thin compressed cells separated the long process of the incus and the head of the stapes. In the eighteenth week, the incus and malleus were ossified in the middle portion, and young articulation capsule was observed around the incudomallear joint. However, the connection of the lenticular process and the head of the stapes were still separated by a few rows of immature compressed cells. These findingss would suggest that the incudostapedial joint is more immature than the incudomallear joint at this stage. Observations on the pattern of early development of the incudostapedial joint suggest that there is a possibility that the head of the stapes, the lenticular process and the long process of the incus are derived from one origin. In the twenty-second week, the long process of the incus and the crura of the stapes were ossified and the articulation capsule was completed to become adult form. The fact that the incudomallear joint was completed one month ahead the completion of the incudostapedial joint would be a possible cause of higher incidence of separation of the incudostapedial joint than that of fused malleus and incus in middle ear malformations.

Etiopathology of delayed failure in stapedectomy

Analysis of 26 revision operations after previous stapedectomy, done at All-India Institute of Medical Sciences from Jan. 1967–March 1970, has been done. Two of the causes not previously described were found in three patients. They have been discussed in detail. A short review of available literature has been done. The following conclusions have been reached:— (1) Stapedectomy in obliterative otosclerosis may be followed by extensive regrowth of focus causing pressure on polythene tube prosthesis and leading to pressure necrosis of the long process of incus. (2) Dislocation of polythene tube may occur at lower end due to fibrosis and pull on the prosthesis. (3) Surgical revision for obliterative otosclerosis in young patients is likely to be unsuccessful.

Congenital anomalies of the ossicles without deformities of the external ear

Anomaly of the ossicles is frequently seen in a patient with congenital anomalies of the head or face, such as congenital obstruction of the external ear canal, Treacher Collins syndrome or cephalopathy. Congenital anomaly of the ossicles however is not a rare occurrence even in a patient without anomalies of the head or face.Here, we would present our own experience with six cases of congenital anomalies of the ossicles and with one case of congenital deformity of the round window. The patients with anomalies of the ossicles had non-progressive hearing impairment of purely conductive type, except for one case which had been accompanied by otosclerotic changes and had a bone conduction loss.Case 1. 24-year-old male.An exploratory operation of the left ear had revealed that there were a bony fusion of the short process of incus with the horizontal semicircular canal and a dislocation of the long process of incus, resulting in separation of the incudostapedial joint. The bony bridge was removed and the separated joint was reconstructed by means of a polyethylene tube strut. The acoustic gain was 42db.Case 2. 41-year-old male.Congenital anomaly of the left middle ear was found to be a bony fusion of the short process of incus with the horizontal semicircular canal. The bony bridge was removed, resulting in a hearing improvement. But his hearing became wor se after several months, probably due to recurrence of ankylosis.Case 3. 21-year-old male (left ear)Case 4. 24-year-old male (left ear)Both cases had congenital separation of the incudostapedial joints, due to maldevelopment of the long process of incus. These separated joints were reconstructed by means of a polyethylene tube strut. Hearing improvement were considerable in both cases.Case 5. 31-year-old male.Congenital absence of the head and crus of the stapes was found in his left ear. The foot-plate was movable. A polyethylene tube collumela was introduced between the long process of incus and the foot-plate. Hearing gain was about 30db.Case 6. 38-year-old female.The patient had otosclerosis in both ears. Congeaital separation of the incudostapedial joint was seen in the left ear. Following a stapes mobilization operation, the ossicular chain was reconstructed by means of a polyethylene tube strut. Hearing gain was considerable.Case 7. 25-year-old female (right ear).The round window niche was remarkably narrow.

Importance of incudostapedial joint and long process of incus

Importance of long process of incus and the incudostapedial joint is emphasized and blood supply of the long process should not be neglected in our zeal of doing stapedectomy while in tympanoplasty its absence presents the difficulty.