October 21, 2018

Indications of Sciatica in a Physical Exam

By Rebecca Shoemaker, MD, Hampton Roads Orthopaedics & Sports Medicine

 

Sciatica is a descriptive term that refers to radiation of pain from the lower back down the back of the thigh and leg in the distribution of the sciatic nerve. A true sciatica describes irritation of the six nerve roots that comprise the sciatic nerve. When sciatica originates from these roots, there may be key findings indicative of radiculopathy on a physical exam. 

For an L5 or S1 radiculopathy, there may be a positive straight leg raise or crossed straight leg raise in a supine position. In a seated position, there may be a positive Bechterew or slump test. Cervical flexion may also reproduce the pain, as it causes traction of the dura, lumbosacral nerve roots and sciatic nerve. 

In the presence of an S1 radiculopathy, motor testing may discover weakness in the ankle plantar flexors and hip extensors, along with a decreased or absent Achilles reflex. In the case of an L5 radiculopathy, there also may be weakness in the ankle dorsiflexors, inverters and everters, hip abductors or extensor hallucis longus, as well as a decreased or absent patellar reflex. 

Although facet arthropathy generally does not extend past the knee, it can refer pain down the posterior thigh and even into the leg. More often, the patient will experience worsening pain with extension and facet loading, as opposed to a patient with discogenic pain who will frequently complain of increased pain with lumbar flexion.  

Piriformis syndrome is a rare condition that causes pain in the distribution of the sciatic nerve. It may occur due to muscle hypertrophy, fibrosis following trauma or anatomical anomalies involving the nerve roots. The patient may have pain with sitting due to weight bearing on the buttock, a positive piriformis test, or pain with palpation at the lateral margin of the sacrum. 

There are a few other conditions that can mimic sciatica yet occur outside the lumbosacral spine. Sacroiliitis can present as pain localized to the low back or buttock, but it also can refer pain laterally along the waistline, into the groin and hip and down the posterior or lateral thigh. While the pain usually stops at the knee, it can extend into the lateral or posterior leg. The patient may have tenderness with palpation to the posterior superior iliac spine, positive distraction, thigh thrust or compression test, Gaenslen’s test or a positive FABER test contralateral to the pathologic side.

Bursitis also may refer pain down the leg: trochanteric bursitis down the lateral thigh, and ischial bursitis down the posterior thigh. In the case of refractory trochanteric bursitis, an underlying piriformis syndrome is a possibility given the insertion of the piriformis muscle on the greater trochanter.

The mainstays of treatment for all of these conditions are conservative and include rest, physical therapy, non-steroidal anti-inflammatory drugs and oral steroid tapers. Resistant cases may respond to steroid injections. 

In the event of radiculopathy with weakness, sensory changes or pain not alleviated by conservative measures or epidural injections, referral to a surgeon may be appropriate. Additionally, early surgery may be warranted in the case of nerve root compression with severe weakness.

Dr. Shoemaker specializes in interventional pain management and physical medicine and rehabilitation at HROSM. She is Fellowship trained in Pain Medicine. hrosm.com