Alfonso Iodice D'Enza

The endoscopic endonasal approach for the management of craniopharyngiomas: a series of 103 patients

OBJECT Despite their benign histological appearance, craniopharyngiomas can be considered a challenge for the neurosurgeon and a possible source of poor prognosis for the patient. With the widespread use of the endoscope in endonasal surgery, this route has been proposed over the past decade as an alternative technique for the removal of craniopharyngiomas. METHODS The authors retrospectively analyzed data from a series of 103 patients who underwent the endoscopic endonasal approach at two institutions (Division of Neurosurgery of the Università degli Studi di Napoli Federico II, Naples, Italy, and Division of Neurosurgery of the Bellaria Hospital, Bologna, Italy), between January 1997 and December 2012, for the removal of infra- and/or supradiaphragmatic craniopharyngiomas. Twenty-nine patients (28.2%) had previously been surgically treated. RESULTS The authors achieved overall gross-total removal in 68.9% of the cases: 78.9% in purely infradiaphragmatic lesions and 66.3% in lesions involving the supradiaphragmatic space. Among lesions previously treated surgically, the gross-total removal rate was 62.1%. The overall improvement rate in visual disturbances was 74.7%, whereas worsening occurred in 2.5%. No new postoperative defect was noted. Worsening of the anterior pituitary function was reported in 46.2% of patients overall, and there were 38 new cases (48.1% of 79) of postoperative diabetes insipidus. The most common complication was postoperative CSF leakage; the overall rate was 14.6%, and it diminished to 4% in the last 25 procedures, thanks to improvement in reconstruction techniques. The mortality rate was 1.9%, with a mean follow-up duration of 48 months (range 3-246 months). CONCLUSIONS The endoscopic endonasal approach has become a valid surgical technique for the management of craniopharyngiomas. It provides an excellent corridor to infra- and supradiaphragmatic midline craniopharyngiomas, including the management of lesions extending into the third ventricle chamber. Even though indications for this approach are rigorously lesion based, the data in this study confirm its effectiveness in a large patient series.

Endoscopic Endonasal Transsphenoidal Removal of Recurrent and Regrowing Pituitary Adenomas: Experience on a 59-Patient Series

OBJECTIVE The nature of the pituitary adenomas itself exposes the possibility of a recurrence of the tumor. The aim of this study was to evaluate the effectiveness of the endoscopic endonasal transsphenoidal approach for the removal of recurrent and residual pituitary adenomas, already treated by a microscopic or endoscopic transsphenoidal approach or by a transcranial route. METHODS A total of 59 adult patients with a recurrent or regrowing pituitary adenoma underwent surgery using a pure endoscopic endonasal transsphenoidal approach. Of these patients, 31 were previously operated on by a microsurgical transsphenoidal approach, 22 by means of an endoscopic transsphenoidal route, and 6 via a transcranial route. The patient series has been divided into 3 tiers according to the primary surgery, and the results were evaluated accordingly. RESULTS Gross total removal was achieved in 37 of our cases (62.7%). According to prior surgery at primary disease, we found that in the subgroup of patients who underwent a microsurgical transsphenoidal approach we achieved gross total removal in 23 cases (74.2%; 23 of 31), whereas in the group of patients who underwent the endoscopic endonasal approach, gross total removal was attained respectively in 13 cases (59.1%; 13 of 22) and in only 1 case of those who underwent the transcranial approach (16.7%; 1 of 6). Postoperative complications included 1 case (1.7%) of cerebrospinal fluid leak and meningitis, and 1 with an hematoma in the tumor field (1.7%); both needed surgical reoperation. CONCLUSIONS The endoscopic endonasal approach is a safe and effective procedure for the management of recurrent and/or regrowing pituitary tumors previously treated by either a microsurgical or an endoscopic approach.

Exploratory data analysis leading towards the most interesting simple association rules

Association rules (AR) represent one of the most powerful and largely used approaches to detect the presence of regularities and paths in large databases. Rules express the relations (in terms of co-occurrence) between pairs of items and are defined in two measures: support and confidence. Most techniques for finding AR scan the whole data set, evaluate all possible rules and retain only rules that have support and confidence greater than thresholds, which should be fixed in order to avoid both that only trivial rules are retained and also that interesting rules are not discarded. A multistep approach aims to the identification of potentially interesting items exploiting well-known techniques of multidimensional data analysis. In particular, interesting pairs of items have a well-defined degree of association: an item pair is well defined if its degree of co-occurrence is very high with respect to one or more subsets of the considered set of transactions.

Low-dimensional tracking of association structures in categorical data

In modern applications, such as text mining and signal processing, large amounts of categorical data are produced at a high rate and are characterized by association structures changing over time. Multiple correspondence analysis (MCA) is a well established dimension reduction method to explore the associations within a set of categorical variables. A critical step of the MCA algorithm is a singular value decomposition (SVD) or an eigenvalue decomposition (EVD) of a suitably transformed matrix. The high computational and memory requirements of ordinary SVD and EVD make their application impractical on massive or sequential data sets. Several enhanced SVD/EVD approaches have been recently introduced in an effort to overcome these issues. The aim of the present contribution is twofold: (1) to extend MCA to a split-apply-combine framework, that leads to an exact and parallel MCA implementation; (2) to allow for incremental updates (downdates) of existing MCA solutions, which lead to an approximate yet highly accurate solution. For this purpose, two incremental EVD and SVD approaches with desirable properties are revised and embedded in the context of MCA.