PORTA, LUIGI

(b. Pavia, Italy, 4 January 1800; d. Pavia, 9 September 1875)

surgery.

Porta’s parents were of modest means and his father died when he was young. He therefore received his schooling only at considerable sacrifice. He was awarded a degree in surgery from the University of Pavia in 1822, and was immediately sent by his teacher Antonio Scarpa to Vienna for further study. He returned to Pavia in 1826 and took the degree in medicine in the same year. In 1832 he was appointed professor of clinical surgery, a position that he held for more than forty years.

Porta’s work lay in many surgical fields; that in which he was preeminent was experimental pathological surgery. By his research on the pathological changes caused to arteries by ligation and torsion he contributed to establishing the foundations of modern vascular surgery. Beginning in 1835 he made an extensive series of animal experiments on more than 270 animals of various species, including dogs, sheep, goats, horses, asses, oxen, and rabbits. He continued these investigations for nine years, and his results, coupled with his clinical observations, led him to significant discoveries concerning experimentally induced pathological changes of the arteries. Among these, his findings on the manner in which collateral circulation is established following the obliteration of parts of the arteries are of particular interest.

In his work Porta distinguished between direct collateral circulation, which occurs by anastomosis from the ends of the trunk of an obliterated artery, and indirect collateral circulation, which arises from the anastomosis of the secondary vessels of the limb to the periphery of the main trunk of the obliterated artery. He also made a distinction between two types of anastomosis produced by ligation of the artery: primitive, or preformed anasomoses originate through dilation of vasa vasorum, which are enlarged by the action of the ligature, while newly formed anastomoses arise from the vasa vasorum through hyperplasia, rather than dilation. He further pointed out that direct collateral circulation through anastomoses, in which anatomical continuity was maintained, could follow simple ligature of an artery, and that it was of great functional importance in cases in which the vessel was poor in collateral branches.

Indirect collateral circulation, Porta concluded, occurs through anastomoses of deep muscular vessels and superficial subcutaneous ones, although intramuscular, intermuscular, intranervous, periosteal, and subcutaneous vessels may all play a part. The establishment of an indirect collateral circulation was, he added, substantially the result of the conversion of the lateral anastomotic system to the chief channel of circulation; in the process the lateral anastomotic system is modified, since its branches, initially numerous and slender, decrease in number and increase in diameter. He found that these alterations were not constant, however, but varied in the form and length of time that they took according to animal species. Nor was the time required for the establishment of collateral equilibrium constant, since according to Porta’s results it varied from case to case.

In addition Porta did work in anesthesiology, thyroid pathology, urology, traumatology, and autoplasty. He made a significant contribution, too, to lithotripsy, for which procedure he developed a special instrument, a combination of drill and pincers. He made a number of anatomical and pathological collections, which he gathered in the museum that he founded and, in 1860, gave the university; upon his death, the university received all his property.

Porta received many honors from both Italian and foreign academies. He was a senator of the Kingdom of Italy, head of the Medical and Surgical Faculty at Pavia, and for a time the rector of the university. He never married, and cared for his mentally deranged sister throughout her lifetime.

BIBLIOGRAPHY

I. Original Works. Porta wrote some fifty scientific works, listed in Alfonso Corradi, in “Porta Comm. Luigi Senatore del Regno,” in Annuario della Reale Università di Pavia (1875–1876), 34–60. The most important of these are Delle alterazioni patologiche delle arterie per la legatura e la torsione. Esperienze ed osservazioni . . . (Milan, 1845); and Della litotrizia di Luigi Porta (Milan, 1859). A number of his manuscripts, as well as numerous other mementos and original preparations (including some concerning collateral circulation), are preserved in the historical museum at the University of Pavia.

II. Secondary Literature. In addition to Corradi, cited above, see Angelo Scarenzio, “Commemorazione di Luigi Porta,” in Rendiconti dell’Istituto lombardo di scienze e lettere, 2nd ser., 20 (1887); and Bruno Zanobio, “The Research of Luigi Porta on Morbid Changes of the Arteries Induced by Ligation and Torsion,” in Clio medica, 8 (1973), 305–313.

Bruno Zanobio