Pathophysiology, Signs and Complications

Part I ? ( There 's still Sandhya and Daksha's )

Lumbar spinal stenosis
Narrowing of the spinal canal, nerve root canals, or intervertebral foramina due to spondylosis and degenerative disk disease.
It usually occurs in the cervical and lumbar spine. There are 2 forms of spinal stenosis:
Primary stenosis : congenital and relatively uncommon.
Acquired stenosis : degenerative condition.
generally become symptomatic at age 50 years or older.
can include osteophyte formation, facet hypertrophy, bulging disks, and hypertrophy of the ligamentum flavum. These processes can result in canal or foraminal narrowing.

Pathophysiology :
· There may be physiological stress when osteophytes form anteriorly or posteriorly. Posteriorly, it narrows the intraspinal diameter and cause lateral stenosis and impingement of the spinal cord.
· With age, the disks dehydrate and can compress and bulge. This can cause tilting, slippage, or rotation of vertebral bodies. The compressed disks result in shortening of the spinal column, which causes the ligamentum flavum to buckle inward and compress the spinal sac and nerve roots.

Signs

Lower back pain, radiating leg pain (unilateral or bilateral), and possible bladder and bowel difficulties.
Radiating arm pain with numbness and paresthesia in the involved dermatomes.
Associated weakness occurs in the muscles supplied by that nerve root.
Shows symptoms of myelopathy (spinal cord dysfunction); finger numbness, clumsiness, and difficulty walking due to spasticity and loss of position sense, bowel and bladder control dysfunction.
Standing and bending backwards can make the symptoms worse. This is because bending forward increases the space in the spinal canal and vertebral foramen, while bending backward decrease the space. It more comfortable for patients to sit or lean forward and are unable to walk for long distances. Patients often state their symptoms are improved when bending forward while walking with the support of a walker or shopping cart.

Piriformis syndrome.
· The sciatic nerve exits the pelvis via 4 routes:

Anteriorly to the piriformis between the rims of the greater sciatic foramen.

Passes through the piriformis; the tibial portion passes anterior to the piriformis muscle.

Above and posterior to the piriformis muscle, whereas the tibial branch passes anterior to the piriformis muscle.

Penetrates the piriformis muscle.

· Occurs when the muscle becomes tight or goes into spasms, putting pressure on the sciatic nerve, pain-frequently described as tingling or numbness-in the buttocks and along the nerve.
· The pain may radiate down the back of the thigh but doesn't extend below the knee.
· Can be caused by prolonged sitting, car accidents and falls or trauma to the buttocks or gluteal region.
· Location of the pain is often imprecise, but it is often present in the hip, coccyx, buttock, groin, or distal part of the leg. The history and physical findings are key elements in differentiating the more common forms of LBP and piriformis syndrome.
· The history of this condition stems from one of many causes of lower back and leg pain.

Signs
In piriformis syndrome, the only true-positive sign is tenderness over the gluteal region.
The pain can be reproduced with maximum elongation of the piriformis muscle in flexion, adduction, and internal rotation of the hip.
Weakness can be observed with resisted external rotation and abduction of the hip.
Several authors describe the use of the following signs in diagnosing piriformis syndrome:
Lasegue sign: Pain is present in the vicinity of the greater sciatic notch during extension of the knee with the hip flexed to 90 º, tenderness to palpation of the greater sciatic notch is noted.
Pace sign: Pain and weakness are present on resisted abduction-external rotation of the thigh.
Freiberg sign: Pain occurs with passive internal rotation of the extended thigh when the patient is supine.

Complications ( in general )

Partial or complete loss of leg movement
Partial or complete loss of sensation in the leg
Recurrent or unnoticed injury to the leg
Side effects of medications

References :
http://www.mayoclinic.com/print/sciatica/DS00516/METHOD=print&DSECTION=all/
http://emedicine.medscape.com/article/247887-overview
http://www.medicinenet.com/lumbar_stenosis/page2.htm
http://www.nlm.nih.gov/medlineplus/ency/article/000686.htm
http://www.ninds.nih.gov/disorders/piriformis_syndrome/piriformis_syndrome.htm
http://www.sciatica.org/piriformis/index.html