Saudi Arabia's 87-year old King Abdullah will undergo surgery for a stretched ligament in his lower back in Riyadh later this week his palace said in a statement on Tuesday.
"The operation will be carried out in the next few days in Riyadh," the statement said.
Last November, Abdullah flew to New York for a surgery to repair a debilitating herniated disc complicated by a hematoma that put pressure on his spine.
That surgery was declared a success, as was a second operation to repair several vertebrae and Abdullah returned to Saudi Arabia this February.
The monarch's advanced age combined with health problems have raised concerns about a smooth future political succession future in Saudi Arabia, which has been ruled by the Al-Saud family since 1932.
In 2006 King Abdullah, who has ordered the formation of the Allegiance Council in hopes of giving the House of Saud a greater voice in succession above the level of Sultan, which has always been a source of intense behind-the-scenes infighting.
Under Abdullah's system the monarch nominates three candidates for the Allegiance Council to select a Crown Prince from. If the council rejects all three of the king's candidates they may select one of their own, but the king also has the right to reject their candidate and insist on one of their own.
If this happens the allegiance council, which consists of five members of the House of Saud and two members of the rival Sudari line, holds a vote to determine which candidate will be King.
However, succession must be also be approved by the influential Ulema, a body of Islamic religious leaders and jurists, who must also prove new laws and royal decrees.
Abdullah's half-brother, Crown Prince Sultan bin Abdul Aziz, who has held the post of defense minister ever since 1962, is 83 and believed to be battling cancer.
Prince Nayef, 77, third in line to the Saudi throne, was appointed second deputy prime minister in March 2009.
Sources: Associated Press, AFP, Gulf News