Saying the operation had been long planned, the 66-year-old pinned his ongoing participation in the country's politics on its outcome.
“After undergoing the operation and in accordance with my health and the medical prognosis, I will decide in what form I will continue my political work,” Lafontaine said in Berlin.
Lafontaine had already announced he would give up co-leadership of his party's parliamentary group following the September 27 general election. But he will keep his seat in parliament and remain co-head of the party. There has been speculation in recent weeks that he had decided return to the political fray in his native state of Saarland for personal reasons.
Der Spiegel magazine reported this week Lafontaine's wife was pushing him to retreat from The Left's leadership in parliament amid unsubstantiated rumours he had had an affair with Sahra Wagenknecht, an avowed communist and MP for The Left.
Once the leader of the centre-left Social Democrats (SPD), Lafontaine took the helm of the The Left in 2007 after it was formed by disgruntled western German trade unionists and members of the successor party to the East German communist party.
Serving as finance minister under former Chancellor Gerhard Schröder, Lafontaine quit in a huff in 1999. He then proceeded to attack the SPD for its unpopular welfare and economic reforms before leaving the party in 2005 after 39 years of membership.
Under Lafontaine's leadership, the leftists won 11.9 percent of the vote in September, their best ever election result.