Intraocular lens glucose sensor.

Ocular spectroscopy, which is the use of the eye to monitor optically the concentration of metabolites in the body, has been successfully applied to monitor aqueous humor glucose concentration. In the United States, 1.7 million intraocular lenses are currently implanted yearly. Because patients with diabetes are more likely to develop cataracts at an earlier age, a relatively high proportion of the patients receiving intraocular lenses have diabetes. Last year, 110,000 patients with diabetes received intraocular lens implants of various materials. We have successfully polymerized a fluorescent complex within a hydrogel intraocular lens that responds well to glucose concentration.

[Trans-canal mastoidectomy]. / Mastoidectomía transcanal.

UNLABELLED: The controversy regarding the best procedure for treating middle ear cholesteatoma has lasted over 100 years. This paper discusses our current methods for dealing with cholesteatoma, always through external ear or transmeatal mastoidectomy. We present the results of three years of follow-up. MATERIAL AND METHODS: A prospective study was made of 215 ears operated for cholesteatoma using a transcanal approach with one of three techniques: "on demand" DAA mastoidectomy, modified radical mastoidectomy, and radical mastoidectomy with obliteration. Three parameters were used to evaluate results: stability of the mastoid cavity, integrity of the neotympanum, and evolution of hearing. RESULTS: The rate of cholesteatoma recurrence in ears operated with these techniques was much lower than that found in canal-wall-up techniques. Only 3 of the 215 cases (1.4%) remained unstable due to different causes three years after surgery. DISCUSSION AND CONCLUSIONS: Due to the high rate of cholesteatoma recurrence, canal-wall-up mastoidectomy has been abandoned in our clinic. Open techniques using a transmeatal approach, with or without obliteration, and the so-called "on demand" mastoidectomy, have yielded more stable results, although postoperative care is more critical.

Chondro-perichondrial connection in middle ear surgery.

Hearing conservation or gain are important parameters of tympanoplastic surgery. The frequency of this surgical procedure and the difficulty in obtaining tissues due to the increased risk of H.I.V. transfer has made the use of synthetic products somewhat more acceptable in contrast with the use of organic substances (homograft ossicles, bone, cartilage and perichondrium, etc...). We have been using tissues of the same patient (50), during a period of three years with a specimen constituted of cartilage and perichondrium designed as a "butterfly" and with very promising tympanoplastic and functional results. The tympanoplastic results were evaluated eighteen months postoperatively as follows: good: 86%, aural discharges that disappeared later 12%, perforations: 0%, keratin neoformations: 2%. Functional results were evaluated three years later as follows: gain more than 15 dB: 72%, same: 14%, worse: 14%.

[Revision of stapedectomy (110 ears)]. / Revisión de estapedectomía (110 oídos).

We have carried out a retrospective study of 110 ears in patients affected with otosclerosis who underwent revision of stapedectomy, from 1979 to 1991, because they did not achieve hearing improvement or still presented persistent dizziness after primary stapedectomy. In our series, the most common causes of surgical failure after the first surgery are: displacement of the prosthesis (36.3%), ossicular chain alterations (21.8%) and regrowth of otosclerotic bone in the oval window (19.9%). One year after surgery, hearing test was compared with preoperatory tonal audiometry, finding and improvement in 48.1% (closure of 20 dB HL or more of the air-bone GAP), no changes in 43.6% and deterioration of the audition in 8.1%. Finally, we give some advises to prevent hearing loss in the revision of stapedectomy.

[Chondro-perichondrial connections in otic surgery (CPC)]. / Conexiones condropericóndricas en la cirugía ótica (CCP).

Tympanoplasty does not resolve problems such as tympanic reconstruction, pneumatic cavity and ossicular transmission mechanism. With the purpose to solve these problems, we used autografts of tragal cartilage with its perichondrial membrane. In just one surgical procedure, we built a transmission mechanism and a consistent new tympanic membrane. Results obtained after 2 years of experience are very encouraging, since postoperative auditive function improves up to 75%; also, a good pneumatic cavity and a well vascularized new tympanic membrane are achieved. Reabsorption of the cartilage was not seen in any case.