[Anatomical landmarks and surgical limits in the suboccipital transmeatal approach to the acoustic neuroma]

INTRODUCTION

To completely remove the intracanalicular portion of the acoustic neuroma through the retrosigmoid approach, we must open the posterior wall of the internal auditory canal (IAC). Therefore, drilling the IAC is one of the key steps we need to take in the transmeatal surgical approach. Nevertheless, there are no clear anatomical landmarks to identify structures such as the semicircular canals, the jugular bulb or air cells. The individual anatomical variations and those caused by the tumour itself make preoperative evaluation essential if we wish to avoid complications such as deafness, cerebrospinal fluid leakage, bleeding and air embolism.

OBJECTIVE

We describe here the personal experience of the senior author (EU) in drilling the posterior wall of the IAC, with special reference to the anatomical landmarks and surgical limits in the suboccipital approach to the intracanalicular portion of the acoustic neuromas.

MATERIAL AND METHODS

This work is based on anatomical data obtained from drilling human temporal bones obtained from cadavers, along with our experience with 20 patients who were operated on for acoustic neuroma using Samii's technique.

RESULTS

We did not operate on any purely intracanalicular neurinomas using this approach. Two tumors were grade II (up to 20mm in diameter), 12 were grade III and 6 were grade IV. We did not drill far enough in any of these cases to be able to see the fundus of the IAC, which was confirmed by postoperative CT. Despite this, the tumor was considered to be completely removed in 17 cases. There was no mortality and we has no major complications as a result of drilling the IAC such as cerebrospinal fluid leakage or air embolism. we cannot guarantee that hearing loss of postoperative deafness, which were the norm except in one case of grade II, were caused by nervous, ischemic or labyrinthine lesions.

CONCLUSION

In our material it was not possible to completely expose the IAC fundus using a retrosigmoid approach without injury to labyrinth. The areas in which the risk of secondary complications is greatest when drilling are the inferior wall and the IAC fundus. The medial extension of the suboccipital craniotomy makes drilling the intrameatal tumor exposure easier. There are no intraoperative landmarks to locate the petrous structures while drilling the IAC except for those provided by the surgeon's own experience.

Human T and B cell epitope mapping of Taenia solium paramyosin

Taenia solium paramyosin is an immunodominant antigen in human and porcine cysticercosis that has shown promise as a vaccine candidate against schistosomiasis and some filariasis. There are few studies to identify the immunologically relevant regions of paramyosin. In this work, we characterize the humoral and cellular response of neurocysticercotic patients against T. solium paramyosin. Western blots using different recombinant fragments of T. solium paramyosin, showed that the sera from neurocysticercotic patients were strongly reactive against the carboxyl end region, with poor recognition of the central and amino regions. In contrast, the cellular immune response of patients did not show preferential recognition of any region of paramyosin.

An outbreak of plague including cases with probable pneumonic infection, Ecuador, 1998

During February and March of 1998, 12 sudden deaths were reported among residents of a high-Andean community in Ecuador. All 12 fatalities were members of the same extended family and some had apparent exposure to sick guinea-pigs. Following an initial investigation by public health officials, an additional death was reported in a nearby community in April, also associated with exposure to sick guinea-pigs. Blood samples from humans, dogs, and a rodent were tested for antibody to the F1 antigen of Yersinia pestis by passive haemagglutination assay. Tissue from rodents was subjected to direct fluorescent antibody staining using fluorescein-labelled monoclonal antibody to Y. pestis F1 antigen. Formalin-fixed specimens from the 2 autopsies were evaluated using a 2-step alkaline phosphatase immunoassay with a monoclonal antibody to Y. pestis F1 antigen, and tissues that had not been embedded in paraffin were tested for the presence of DNA encoding the F1 structural antigen by polymerase chain reaction. Serological evaluation of close contacts of the fatalities revealed positive titres to F1 antigen of Y. pestis, the aetiological agent of plague, in 3 contacts from the first community and 1 from the second. Immunohistochemical staining of tissues collected from 2 of the fatalities provided evidence that both had pneumonic plague. Five of 14 dogs found in the communities were seropositive for plague antibody, providing evidence of a recent epizootic plague in the area.

Malignant fibrous histiocytoma of the scalp. Multidisciplinary treatment

BACKGROUND

Malignant fibrous histiocytomas (MFH) are uncommon in the skin, and even less frequent on the scalp. On the scalp they are often very difficult to excise and it is even more difficult to close the resulting wound.

OBJECTIVE

To review all malignant fibrous histiocytomas diagnosed and treated in our Department during the past 6 years, and to describe the multidisciplinary procedure employed to treat one special case of aggressive malignant fibrous histiocytoma on the scalp that recurred twice.

RESULT

Malignant fibrous histiocytomas represent 0.01% of malignant cutaneous tumors in our area. The immediate results after a multidisciplinary treatment performed on a recurrent malignant fibrous histiocytoma located on the scalp were excellent, but recurrence was observed 6 months later. Two years later we have also treated another case of MFH on the scalp. The same surgical technique was performed, but the patient received high-dose-methotrexate-based neoadjuvant chemotherapy (HD-MTX). One year later, this patient is still alive and no signs of recurrence have been detected.

CONCLUSION

When malignant fibrous histiocytoma occurs on the scalp it must be treated immediately by means of an excision with a large peripheral edge of 2 cm from the visual or CAT limits of the lesion, since the first treatment must be definitive.

[Treatment of amyotrophic lateral sclerosis with daily intrathecal TRH. A year's experience. Pilot study II]

This study presents the experience of one year of treatment in patients with amyotrophic lateral sclerosis, with intrathecal TRH administered daily by a subcutaneous reservoir connected to the intrathecal lumbar space by a double catheter system as to provide continuous circulation of CSF and to avoid sac formation since this would be a source of infection. Clinical evaluation was carried out with a scale developed by the authors with the main aim of evaluating the loss of vital motor abilities and not as a localized evaluation. Secondary effects due to the implantation of the reservoir in addition to its use are presented although data were not important. Intrathecal administration of TRH was carried out similarly (600 micrograms/day) with secondary effects being the same as those by other routes of administration although of a lesser intensity. The results of the clinical evaluation at the beginning and end of the treatment as well as after patient follow up demonstrated that beneficial effects do not occur equally in all patients but rather are transitory and do not improve the natural evolution of the disease. The authors conclude that, methodologically, this series study does not enter within the frame of an advisable statistical study since the aim is to provide data for a future controlled study.