Problem: Young was born in Compton, California, the first child of Theodore and Verna Young. His middle name, Romelle, is derived from his father's amateur R&B singing group, The Romells. His parents married in 1964, separated in 1968, and divorced in 1972. His mother later remarried and had three children: sons Jerome and Tyree (both deceased) and daughter Shameka.

Inspired by the Grandmaster Flash song "The Adventures of Grandmaster Flash on the Wheels of Steel", he often attended a club called Eve After Dark to watch many DJs and rappers performing live. He subsequently became a DJ in the club, initially under the name "Dr. J", based on the nickname of Julius Erving, his favorite basketball player. At the club, he met aspiring rapper Antoine Carraby, later to become member DJ Yella of N.W.A. Soon afterwards he adopted the moniker Dr. Dre, a mix of previous alias Dr. J and his first name, referring to himself as the "Master of Mixology". Eve After Dark had a back room with a small four-track studio. In this studio, Dre and Yella recorded several demos. In their first recording session, they recorded a song entitled "Surgery", with the lyrics "calling Dr. Dre to surgery" serving as the chorus to the song. He later joined the musical group World Class Wreckin' Cru under the independent Kru-Cut Records in 1984. The group would become stars of the electro-hop scene that dominated early 1980s West Coast hip hop. "Surgery", which was officially released after being recorded prior to the group's official formation, would prominently feature Dr. Dre on the turntable. The record would become the group's first hit, selling 50,000 copies within the Compton area.  Dr. Dre and DJ Yella also performed mixes for local radio station KDAY, boosting ratings for its afternoon rush-hour show The Traffic Jam. Dr. Dre's earliest recordings were released in 1994 on a compilation titled Concrete Roots. Stephen Thomas Erlewine of the website AllMusic described the compiled music, released "several years before Dre developed a distinctive style", as "surprisingly generic and unengaging" and "for dedicated fans only".  His frequent absences from school jeopardized his position as a diver on his school's swim team. After high school, he attended Chester Adult School in Compton following his mother's demands for him to get a job or continue his education. After brief attendance at a radio broadcasting school, he relocated to the residence of his father and residence of his grandparents before returning to his mother's house. He later dropped out of Chester to focus on performing at the Eve's After Dark nightclub.

What type of surgery?

Answer with quotes: "Surgery", which was officially released after being recorded prior to the group's official formation, would prominently feature Dr. Dre

Question:
The Plastic Ono Band is a band formed by John Lennon and Yoko Ono in 1969 as a vehicle for their collaborative and solo projects. Lennon and Ono had begun a personal and artistic relationship in 1968, collaborating on several experimental releases. Following their marriage in 1969, they decided that all of their future endeavours would be credited to a conceptual and collaborative vehicle, Plastic Ono Band. The band would go on to feature a rotating lineup of many musicians, including Eric Clapton, Klaus Voormann, Alan White, Billy Preston, Jim Keltner, Delaney & Bonnie and Friends, and Lennon's former Beatles bandmates George Harrison and Ringo Starr.
By the beginning of 1973, recording had begun in earnest on Ono's next album, Feeling the Space, featuring a new group of studio musicians. The newest incarnation of the Plastic Ono Band featured guitarist David Spinozza, keyboardist Ken Ascher, bassist Gordon Edwards, percussionists Arthur Jenkins and David Friedman, saxophonist Michael Brecker, pedal steel guitarist Sneaky Pete Kleinow, as well as regular contributor Jim Keltner. The album would be released in November.  Throughout 1973, Lennon and Ono's relationship became strained. By August, the two had begun a period of separation that Lennon called "The Lost Weekend". Lennon began the recording of his own album, Mind Games, using the same players as on Feeling the Space, dubbed "The Plastic U.F.Ono Band". Around the time of the album's release in November, Lennon moved to Los Angeles with new lover May Pang. In October, Lennon began the recording of an album of rock 'n' roll oldies (a contractual obligation due to a lawsuit). These featured many Plastic Ono Band regulars (including much of the "U.F.Ono Band", Klaus Voorman, and the return of Phil Spector to the production chair), but upon release in 1975 as Rock 'n' Roll, it was credited to Lennon alone.  The sessions for Rock 'n' Roll were extremely troubled, and the sessions were abandoned until a later date. In July 1974, Lennon returned to New York to record Walls and Bridges. The new "Plastic Ono Nuclear Band" featured both old and new faces, with Jim Keltner, Kenneth Ascher, and Arthur Jenkins continuing from Mind Games, the returns of Klaus Voorman, Nicky Hopkins, and Bobby Keys, and the addition of guitarists Jesse Ed Davis and Eddie Mottau. Recording was finished in August, and the album was released 26 September and 4 October in the US and UK respectively.  Walls and Bridges would prove to be the last release of new material by the Plastic Ono Band in the 1970s. Lennon subsequently returned to his marriage with Ono and retired from music following the birth of his son Sean. The compilation Shaved Fish was released in October 1975, Lennon's last release credited to the Plastic Ono Band. Upon his and Ono's return to music in 1980 for the album Double Fantasy, they played with an all-new group of studio musicians who were not billed as any variation of the Plastic Ono Band name. Lennon was shot and killed shortly after the release of the album.
Answer this question using a quote from the text above:

What does that mean

Answer:
Throughout 1973, Lennon and Ono's relationship became strained. By August, the two had begun a period of separation that Lennon called "The Lost Weekend