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Approach to the Patient with Low Back Pain

Every discussion of low back pain starts with how ubiquitous and frequent back pain is. We are all aware that 80 percent of us will have a back ache at some point in our life, and for some of us it will become considerably disabling. If the majority of patients who have low back problems will improve with time, how can we logically and efficiently approach the patient with low back pain?

Pain and Complaint Pattern

Patients with low back problems or problems arising from pathology within the spine and the low back generally can be divided into three categories:

Patient with central back pain
Patient who has pain in the back referred into the buttock or upper leg
Patient with true radicular complaints.

Each forum is a separate and distinct entity that needs to be evaluated

Central Low Back Pain

Correct diagnosis for the patient who presents with central low back pain can sometimes be very difficult.

Some differentials are very easy, such as the strain event. One has to be very suspect for the patient who presents with insidious onset of back pain or recurrent back pain after trivial events This is especially true for the patient who is over 50, who does not have a good trauma history, and who has night pain The sources of back pain can be multi varied and challenging. They can range from a urinary tract infection to gynecologic disorders, to osteopenia, and metasratic disease. Usually a good history and physical will start one on a correct diagnostic and therapeutic program

Similarly, the patient who presents with back pain after a single lifting event does not require full radiographic workup and will respond usually to a more functional program consisting of anti-inflammatories, exercise and return to work as the pain will allow. The days of forced bed rest for back pain are thankfully gone

The major dilemma is approaching the patient who has persistent or episodic back pain. If the patient has not responded to the initial conservative measures and their pain has a positional character to it, that is pain, changes if the position changes or is worse when they are up or exercising, the patient is usually started with AP and flexion-extension lateral radiographs to rule out a structural instability. Disc space narrowing alone at L5-S1 in and of itself may not be a symptom generator, but narrowing and especially translation at L4-5 probably indicates that the disc is the source of this pain. A nonsteroidal anti-inflammatory program and a stabilization series of exercises should have symptomatic improvement in a considerable number of patients. Patients with severe mechanical low back pain can be helped by a period of time in a rigid brace or cast. Surgery for central low back pain without other structural anomaly should be considered only after all other modalities have been investigated.

Pain in the Back Referred into the Buttock or Upper Leg

Referred or scierotomal pain, that is pain from the back that radiates into the buttocks and perhaps upper thigh, and usually indicates involvement or disruption of the posterior elements of the spine such as the facet or pars interarticularis. This pain is generally worsened by back extension maneuvers on physical exam Posterior element dysfunction such as spondylolisthesis should be thought about in the young patient who is athletic who starts to have back pain (This is especially true for the patient with hyperextension axial load, stresses such as gymnasts and interior linemen in football) In such a patient, a bone scan could be very helpful in confirming a diagnosis.

The treatment would involve rest, a period of bracing and perhaps surgery This will be covered in a later topic. The older patient with degeneration of the disc leading to a true facet arthropathy, with a strain event where the area around the small joints are bothered, will also present with this type of symptom Again, pain when the patient stands or extends is the hallmark of the diagnosis. Physical findings at times can be tenderness over the iliolumbar insertion, which can sometimes be helped by a local cortisone injection, and a normal neurologic exam The usual treatment is non-steroidal anti-inflammatory medication and a flexion exercise program.

Patient With Radicular Complaints

The patient with true radiculopathy will have a searing or radiating pain that travels from the back down into the foot or ankle. At times they will have a numbness either over an L5 root distribution (in the first web of the foot) or an Si distribution (lateral border of the foot).

In addition they will have a weakness of the foot dorsiflexion, usually evidenced by a foot slap when they walk. This is especially true for the L5 root problem secondary to an L4-5 disc disruption. The majority of disc ruptures leading sciatica are at the lower two disc levels Only about 5 percent of true radicular pain secondary to herniation will come from an upper level disc and lead to a femoral nerve problem. These are the patients who present with groin pain radiating into their thigh to below the knee. One has to be careful in doing the physical exam.to separate these out from the patients who have hip joint pathology, which will have the same radiation.

In general, the patient with a hip joint problem will have to stand still for a second before they can walk off and will have pain that improves as they walk, while those with radiculopathy will deteriorate as they walk. The physical exam finding of an absent knee jerk and a femoral stretch sign will lead to the correct radicular diagnosis, while the physical exam finding of limited internal and external rotation of the hip when the hip is flexed or pain on internal and external rotation of the extended hip will yield a correct diagnosis of hip joint pathology.

Role of an MRI in the Patient with Back Pain

MRI should be kept as a confirmatory study to verify a disc herniation at a clinically diagnosed level MRI can also be helpful in persistent and severe low back pain in ruling out a bony lesion Using MRI as a screening test, however, can be a costly and inaccurate undertaking in that one out of every four asymptomatic patients over 40 will have a lesion seen on MRI, usually a dark disc on T2 weighted image

When to Refer a Patient Who Has a Back Problem

Patients who have an acute onset back event who have been mobilized or manipulated have a 10-20 percent improvement in their pain scores over those who did not A physical therapist trained in this technique or chiropractor can provide this service. Long-term chiropractic maintenance therapy has not proved to be effective, although good studies are lacking. Patients who have had 3-4 weeks unremitting radicular pain or who have a cauda equina syndrome characterized by loss of function of bowel or bladder should he referred to a spine surgeon for consideration for a decompressive procedure. Patients who have a spondylolisthesis or a spinal instability should be referred to a spine surgeon for fusion. Patients with episodic or persistent mechanical back pain who have had a good exercise protocol through physical therapy can be referred to a spine surgeon for consideration of the newer anterior fusion procedures with cages.