A radiologist may assist in this clinical setting by injecting a small dose of medication containing a paralysing agent such as botulinum toxin under high-frequency ultrasound or CT control. This inactivates the piriformis muscle for 3 to 6 months, without resulting in leg weakness or impaired activity. Though the piriformis muscle becomes inactivated, the surrounding muscles quickly take over its role without any noticeable change in strength or gait. Such treatments may be more or less curative (with no return to pain), or may have limited timespans of effectiveness. Surgery
For rare cases with unrelenting chronic pain, surgery may be recommended. Surgical release of the piriformis muscle is often effective. Minimal access surgery using newly reported techniques has also proven successful in a large-scale formal outcome published in 2005. As with injections, the deactivated/ excised muscles role in leg movement is completely compensated for by surrounding hip muscles. Failure of piriformis syndrome treatment may be secondary to an underlying internal obturator muscle injury. Epidemiology
Piriformis syndrome (PS) data is often confused with other conditions due to differences in definitions, survey methods and whether or not occupational groups or general population are surveyed. This causes a lack of group harmony about the diagnosis and treatment of PS, affecting its epidemiology. In a study, 0.33% of 1293 patients with low back pain cited an incident for PS. A separate study showed 6% of 750 patients with the same incidence. About 6–8% of low back pain occurrences were attributed to PS, though other reports concluded about 5–36%.
Sojourn may refer to:

Books and periodicals
Sojourn (comics), a CrossGen comic book series
Sojourn (journal), a journal of social and cultural issues in Southeast Asia
Sojourn (novel), the 1991 novel in the Dark Elf Trilogy by R. A. Salvatore
The Sojourn, a 2011 novel by Andrew Krivak

Music
Sojourn (album), a 1977 album by Mickey Tucker
"Sojourn", a song by Natasha Bedingfield from Unwritten
Sojourn Music, an American Christian music group

Other uses
"Sojourn" (American Horror Story), a television episode
Sojourn, a predecessor of TorilMUD, a text-based online role-playing game
Sevoflurane, trade name Sojourn, an inhalational anaesthetic
Sojourn Shelton (born 1994), American football player

See also
Sojourner (disambiguation)