Dr. Safraz Mohammed University of Ottawa, Neurosurgery, Ottawa Civic Hospital, Ottawa, ON.
Dr. Robert Ravinsky University of Toronto, Division of Orthopaedics, Department of Surgery; Holland Musculoskeletal Program and Division of Orthopaedic Surgery, Sunnybrook Health Sciences Centre, Toronto, ON.
Dr. Albert Yee University of Toronto, Division of Orthopaedics, Department of Surgery; Holland Musculoskeletal Program and Division of Orthopaedic Surgery, Sunnybrook Health Sciences Centre, Toronto, ON.

Abstract
Degenerative conditions of the spine are a major cause of disability, and represent a large economic burden on the health care system. In this review, we have described some of the most common degenerative pathologies of the lumbar spine—low back pain, spinal stenosis, degenerative spondylolisthesis, lumbar disc herniation and cauda equina syndrome—and the diagnostic approach and immediate management from the perspective of the primary care physician. We have emphasized clinical pearls seen in these conditions and specific indications for surgical referral, as well as red flags that should prompt urgent referral for life-threatening entities, such as malignancy and infection.
Key Words: degenerative spine, surgery, lumbar disc herniation, spinal stenosis, spondylolisthesis, radiculopathy.

In this article, we provide an update on current surgical indications for degenerative conditions of the lumbar spine including important clinical pearls of diagnosis. There are many physician specialists that treat spinal pathologies, such as physiatrists, rheumatologists, pain specialists, and surgeons to name a few. This educational update will provide context regarding current surgical indications that may be helpful to primary care physicians when considering a referral to a spinal specialist for either non-surgical care or surgical management. Spinal conditions that will be discussed include: back pain, spinal stenosis and neurogenic claudication, lumbar disc herniation, spondylolisthesis, and cauda equina syndrome.

Low Back Pain
Depending upon the study, low back pain is the second to fifth most common reason for all physician visits in North America.^1,2 Acute back pain is defined as occurring within the last 4 weeks, while subacute back pain is within 3 months.¹ Approximately 25% of North American adults have reported acute low back pain lasting at least a day and it is estimated that low back pain directly incurs approximately $26 billion dollars annually in the U.S. in health care costs.² The majority of patients who report low back pain have short, self-limited episodes. Of those who sought medical attention, the majority typically improve within the first 6 weeks, rapidly returning to work.¹ Of the patients who report an acute episode of back pain, up to one third will report continued back pain one year after the acute episode. It is estimated that 75% of the cost associated with low back pain is attributed to less than 5% of people with back pain disability. Several studies have shown significant variation in the use of diagnostic tests and management plans, with similar outcomes in the low back pain patient populations.¹

Clinicians should ensure that a focused history and a thorough physical examination is performed to help place patients with low back pain into several key categories: (a) nonspecific low back pain (Pattern I or II), (b) back pain potentially associated with radiculopathy leg symptoms (Pattern III) or leg claudication from structural spinal stenosis (Pattern IV), or (c) back pain potentially associated with another specific spinal cause (i.e. red flags). The history should also include assessment of psychosocial risk factors, which predict risk for chronic disabling back pain.³

In his landmark publications, Dr. Hall described a classification for low back pain (Back Dominant—Patterns I and II; Leg dominant—Pattern III (sciatica) and IV (claudication)).^4,5 Patients may have both back and leg pain symptoms and it remains critically important to determine if the symptoms are back dominant (i.e. nonsurgical treatment for most) or leg dominant (i.e. surgery may be helpful in those not improving with non-op treatment).

In approximately 85% of low back pain patients, no anatomic cause can be elucidated. Red flag symptoms or signs, suggesting a non-degenerative etiology for back pain should be ruled out. To elucidate the risk factors for cancer, prospective data have demonstrated four key questions for patient (Table 1).