Human inner ear blood supply revisited: the Uppsala collection of temporal bone-an international resource of education and collaboration.

BACKGROUND: The Uppsala collection of human temporal bones and molds is a unique resource for education and international research collaboration. Micro-computerized tomography (micro-CT) and synchrotron imaging are used to investigate the complex anatomy of the inner ear. Impaired microcirculation is etiologically linked to various inner ear disorders, and recent developments in inner ear surgery promote examination of the vascular system. Here, for the first time, we present three-dimensional (3D) data from investigations of the major vascular pathways and corresponding bone channels. METHODS: We used the archival Uppsala collection of temporal bones and molds consisting of 324 inner ear casts and 113 macerated temporal bones. Micro-CT was used to investigate vascular bone channels, and 26 fresh human temporal bones underwent synchrotron radiation phase contrast imaging (SR-PCI). Data were processed by volume-rendering software to create 3D reconstructions allowing orthogonal sectioning, cropping, and soft tissue analyses. RESULTS: Micro-CT with 3D rendering was superior in reproducing the anatomy of the vascular bone channels, while SR-PCI replicated soft tissues. Arterial bone channels were traced from scala vestibuli (SV) arterioles to the fundus, cochlea, and vestibular apparatus. Drainage routes along the aqueducts were examined. CONCLUSION: Human inner ear vessels are difficult to study due to the adjoining hard bone. Micro-CT and SR-PCI with 3D reconstructions revealed large portions of the micro-vascular system in un-decalcified specimens. The results increase our understanding of the organization of the vascular system in humans and how altered microcirculation may relate to inner ear disorders. The findings may also have surgical implications.

Variational anatomy of the human cochlea: implications for cochlear implantation.

HYPOTHESIS: To study variations in human cochlea anatomy with potential implications for cochlear implantation surgery. BACKGROUND: A comprehension of the anatomic variations of the human cochlea is essential for understanding the degree of surgical trauma induced by inserting various electrode arrays in cochlear implantation surgery. Variations in anatomy may also limit the potential for performing hearing preservation. METHODS: We studied 73 archival, nonselected, adult, corrosion casts of human inner ears. Anatomic reference points were constructed from photographic reproductions taken at different angles, and various dimensions were assessed using planimetry. Anatomic variants with particular clinical/surgical interests were pinpointed. RESULTS: Results showed that the human cochlea is individually shaped, varying greatly in dimensions ("fingerprint"). The outer cochlear wall length ranged from 38.6 to 45.6 mm with a mean length of 42.0 mm. The first turn represented 53% of the total length and ranged from 20.3 to 24.3 mm. The number of quadrants varied from slightly more than 8 to 12. The facial nerve canal ran in close proximity to the upper first turn explaining facial nerve excitement during stimulation of electrodes in this region in some instances. The internal diameter (height) of the cochlear tube in the first turn varied broadly (1.6-2.6 mm), occasionally with limited space for conventional implants. CONCLUSION: The human cochlea exhibits extensive anatomic variations. These variations will influence the location of cochlear implant arrays and affect the potential of hearing preservation surgery. Our results may explain the surgeon's difficulties sometimes to insert electrode arrays even in so-called "normal" cochleae.

Patient-rating of long term results of silicone implant arthroplasty of the scaphoid.

Thirty-two patients had silicone implant arthroplasty of the scaphoid in our unit between 1974-1988. Ten years later eight had had their implants removed because they had failed. Twenty-four of the 32 were reviewed at an intermediate clinical follow up examination between 1988-89 and 21 by patient rated wrist evaluation 10 years later. Grip strength compared to the non-injured hand varied between 38% and 136% (mean (SD) 78 (25)%). Nine of the 24 wrists showed no signs of bone cysts, while 15 had intraosseous cysts of various sizes. Patient-rated evaluation gave a median subjective long term overall wrist score of 25, a pain score of 27, and a function score of 22 on a scale from 0 (best) to 100 (worst). Nine out of 21 patients had little or no pain, and 13 out of 21 had total scores of under 25. Many of these patients reported good subjective benefit from silicone scaphoid arthroplasty.