Piriformis syndrome 1104401 225933497 2008-07-16T02:20:14Z Bunnyhop11 7345738 /* Treatment */ {{Infobox_Disease | Name = {{PAGENAME}} | Image = Gray832.png | Caption = Nerves of the right lower extremity Posterior view. | DiseasesDB = | ICD10 = | ICD9 = | ICDO = | OMIM = | MedlinePlus = | eMedicineSubj = pmr | eMedicineTopic = 106 | MeshID = }} '''Piriformis syndrome''' is a [[neuromuscular]] disorder that occurs when the [[sciatic nerve]] is [[compressed]] or otherwise irritated by the [[piriformis muscle]]. This causes pain, tingling and numbness in the [[buttocks]] and along the course of the [[sciatic nerve]]. The syndrome may result from [[anatomical]] variations in the [[muscle-nerve relationship]], or from overuse or strain. Recent [[uncontrolled studies]] advanced theories behind the disorder. However, following a large scale formal prospective outcome trial using [[Class A study]] design as outlined by the [[American College of Physicians]], the weight of the evidence-based medicine is that [[piriformis syndrome]] should be considered as a possible [[diagnosis]] when [[sciatica]] occurs without a clear spinal cause <ref name="pmid15739520">{{cite journal |author=Filler AG, Haynes J, Jordan SE, ''et al'' |title=Sciatica of nondisc origin and piriformis syndrome: diagnosis by magnetic resonance neurography and interventional magnetic resonance imaging with outcome study of resulting treatment |journal=Journal of neurosurgery. Spine |volume=2 |issue=2 |pages=99–115 |year=2005 |pmid=15739520 |doi=}}</ref><ref name="pmid17030664">{{cite journal |author=Lewis AM, Layzer R, Engstrom JW, Barbaro NM, Chin CT |title=Magnetic resonance neurography in extraspinal sciatica |journal=Arch. Neurol. |volume=63 |issue=10 |pages=1469–72 |year=2006 |pmid=17030664 |doi=10.1001/archneur.63.10.1469}}</ref> The need for [[controlled studies]] is supported by studies of [[spinal disk disease]] that show a high frequency of [[abnormal disks]] in [[asymptomatic]] patients.<ref name="pmid11172169">{{cite journal |author=Deyo RA, Weinstein JN |title=Low back pain |journal=N. Engl. J. Med. |volume=344 |issue=5 |pages=363–70 |year=2001 |pmid=11172169 |doi=10.1056/NEJM200102013440508}}</ref><ref>{{cite web |url=http://content.nejm.org/cgi/content/full/344/5/363/T2 |title=NEJM -- Table 2 |accessdate=2007-11-16 |format= |work=}}</ref> ==[[Pathophysiology]]== In 15% of the population the sciatic nerve passes through the [[piriformis muscle]],<ref>[http://www.geocities.com/akramjfr/sciatic_2_roots.html sciatic_2_roots<!-- Bot generated title -->]</ref> rather than underneath it. These people have been reported by some studies to have a greater incidence of piriformis syndrome than does the general population. Some researchers discount the importance of this relationship in the [[etiology]] of the syndrome.<ref name="pmid12766656">{{cite journal |author=Benzon HT, Katz JA, Benzon HA, Iqbal MS |title=Piriformis syndrome: anatomic considerations, a new injection technique, and a review of the literature |journal=Anesthesiology |volume=98 |issue=6 |pages=1442–8 |year=2003 |pmid=12766656 |doi=}}</ref> Inactive [[gluteal]] muscles also facilitate development of the syndrome. These are important in both [[hip extension]] and in aiding the [[piriformis]] in [[external rotation]] of the [[femur]]. A major cause for inactive gluteals is unwanted [[reciprocal inhibition]] from overactive [[hip flexors]] ([[psoas major]], [[iliacus]], and [[rectus femoris]]). This imbalance usually occurs where the hip flexors have been trained to be too short and tight, such as when someone sits with hips flexed, as in sitting all day at work. This deprives the [[gluteals]] of activation, and the [[synergists]] to the gluteals ([[hamstrings]], [[adductor magnus]], and [[piriformis]]) then have to perform extra roles they were not designed to do. Resulting [[Organ hypertrophy|hypertrophy]] of the [[piriformis]] then produces the typical symptoms. Another [[purported]] cause for piriformis syndrome is stiffness, or [[hypomobility]], of the [[sacroiliac joint]]s. The resulting [[compensatory]] changes in [[gait]] would then result in shearing of one of the origins of the piriformis, and possibly some of the gluteal muscles as well, resulting not only in piriformis malfunction but in other low back pain syndromes as well. Piriformis syndorme can also be caused by an [[overpronation]] of the foot.<ref>{{cite web |url=http://www.coloradorunnermag.com/features/Issue1_Sciatica.html |title=Colorado Runner -- Feature Article |accessdate=2007-11-16 |format= |work=}}</ref> When a foot overpronates it causes the [[knee]] to turn [[medially]], causing the [[piriformis]] to activiate to prevent over-rotating the knee. This causes the piriformis to become overused and therefore tight, eventually leading to piriformis syndrome. It is most frequently associated with [[falling injury]].<ref name="pmid17385355">{{cite journal |author=Kuncewicz E, Gajewska E, Sobieska M, Samborski W |title=Piriformis muscle syndrome |journal=Annales Academiae Medicae Stetinensis |volume=52 |issue=3 |pages=99–101; discussion 101 |year=2006 |pmid=17385355 |doi=}}</ref> ==Other presentations== In addition to causing [[gluteal]] pain that may radiate down the leg, the syndrome may present with pain that is relieved by walking with the foot on the involved side pointing outward. This position externally rotates the hip, lessening the stretch on the piriformis and relieving the pain slightly. Piriformis syndrome is also known as "[[wallet sciatica]]" or "[[fat wallet syndrome]]," as the condition can be caused or [[aggravated]] by sitting with a large [[wallet]] in the rear pocket. <ref>[http://iach.amedd.army.mil/sections/clinics/physicalTherapy/pdf/PIRIFORMIS%20SYNDROME.pdf Piriformis Syndrome (Hip/Buttocks Pain)<!-- Bot generated title -->]</ref> == Diagnosis == Piriformis syndrome is diagnosed by the presence of sciatica - radiating pain in the posterior thigh and lower leg - and the physical exam finding of tenderness in the area of the sciatic notch. [[Magnetic resonance neurography]] is a medical imaging technique that can show the presence of irritation of the sciatic nerve at the level of the sciatic notch where the nerve passes under the piriformis muscle. Neurography can also determine whether or not a patient has a split sciatic nerve or a split piriformis muscle - this may be important in getting a good result from injections or surgery. Image guided injections carried out in an Open MRI scanner can accurately relax the piriformis muscle to test the diagnosis. Other injection methods such as blind injection, flouroscopic guided injection, ultrasound, or EMG guidance can work but are not as reliable. Unlike spine injections, there is no bony target that can show up on X-ray, so fluoroscopy can't show the injection target. It has been difficult to achieve reliable injections with EMG and ultrasound because these methods are not specific to the piriformis muscle. CT guided injections can work well but provide a very high dose of radiation to the pelvis and there is no possibility of shielding sensitive tissues from the radiation. ==Treatment== Treatment usually begins with stretching exercises and massage, and the avoidance of [[contributory]] activities, such as running and bicycling. Some clinicians recommend [[formal]] [[physical therapy]], including the teaching of stretching techniques, [[manual massage]], and strengthening of the [[core muscles]] ([[Abdominals|abs]], [[back]], etc.) to reduce strain on the piriformis muscle. Recommended stretching exercises will usually target the piriformis muscle, but may also include the [[hamstrings]] and [[hip muscles]], in order to adequately reduce pain and increase [[range of motion]]. Patients with piriformis syndrome may also find some pain relief from ice and heat. Ice can be helpful right when the pain starts, or immediately after an activity that usually causes pain (e.g., going up stairs). The ice may be in the form of an ice pack held to the area, or an individual ice cube used in combination with a massaging motion. A [[heating pad]] may be alternated with the ice for relief from the pain. [[Anti-inflammatory]] drugs (such as [[ibuprofen]] or [[naproxen]]) and/or [[corticosteroid]] injections can be used. Occasionally surgery may be recommended. The [[prognosis]] with treatment is generally good. Custom foot [[orthotics]] also help with the treatment and prevention. By correcting a person's [[gait]], the use of the [[piriformis muscle]] is greatly reduced allowing the muscle to relax and heal itself. [[Ultrasound]] is another option for treatment, as it speeds up the [[healing process]]. [[Minimal access surgery]] using newly-reported techniques has also proven successful in a large-scale [[formal outcome]] published recently.<ref>http://www.jnsonline.org/spine/issues/v2n2/toc.html</ref> ==See also== * [[Sciatica]] ==References== {{reflist}} ==External links== *{{NINDS|piriformis_syndrome}} *[http://www.neurography.com/Images/Piriformis/Piriformis1.htm Piriformis syndrome] information including MRI scans at neurography.com *[http://www.nervemed.com/nerve-piriformis.html Piriformis diagnosis] information on diagnosis and treatment at nervemed.com *[http://www.sciatica.org/piriformis.html Treatment and Diagnoisis of Piriformis Syndrome] Medical Paper at sciatica.org *[http://drpribut.com/sports/piriformis.html Piriformis Syndrome: Evaluation and Treatment in Athletes] at drpribut.co *[http://www.sciatica.org/research.html Using Botox for treatment] at sciatica.org *[http://sciatica-hurts.blogspot.com Piriformis syndrome blog] at blogger.com [[Category:Syndromes]] [[Category:Neurology]] [[Category:Orthopedics]] [[de:Piriformis-Syndrom]]