You are in: eMedicine Specialties > Neurosurgery > MEDICAL TOPICS Lumbar Disc DiseaseArticle Last Updated: Jun 23, 2006AUTHOR AND EDITOR INFORMATIONSection 1 of 11
  Author: Kamran Sahrakar, MD, Clinical Professor, Department of Neurosurgery, University of California-Davis Kamran Sahrakar is a member of the following medical societies: Alpha Omega Alpha, American Association of Neurological Surgeons, American Medical Association, California Medical Association, Florida Medical Association, and Nevada State Medical Association Coauthor(s): Martin Melicharek, MD, Assistant Clinical Professor, Department of Neurosurgery, University of California at Davis Editors: Michael G Nosko, MD, PhD, Chief, Division of Neurosurgery, Director of Neurovascular Surgery, Medical Director of Neuroscience Unit, Associate Professor, Department of Surgery, University of Medicine and Dentistry at New Jersey; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Allen R Wyler, MD, Former Medical Director, Northstar Neuroscience, Inc; Herbert H Engelhard III, MD, PhD, Director, UIC Neuro-Oncology Program, Chief, Division of Neuro-Oncology, Associate Professor, Department of Neurosurgery, University of Illinois at Chicago; Allen R Wyler, MD, Former Medical Director, Northstar Neuroscience, Inc Author and Editor Disclosure Synonyms and related keywords: lumbar disc disease, degenerative disc disease, lumbar disc herniation, sciatica, radiculopathy, lumbar discectomy, back pain, cauda equina syndrome INTRODUCTIONSection 2 of 11
  Lumbar disc disease accounts for a large amount of lost productivity in the workforce. Accurate diagnosis can be difficult and often requires interpretation. Treatment is controversial. Surgical treatment can be technically simple and professionally gratifying for the surgeon. Treatment failures are not uncommon, are often related to posttraumatic or work-related injuries, and may result in litigation. As a consequence, this disease can generate distrust of physicians on the part of patients and vice versa. This article clarifies some important guidelines for the diagnosis and treatment of lumbar disc disease. History of the ProcedureThe first published report of lumbar disc herniation with radiculopathy was written by Mixter and Barr in 1934. Surgical treatment was not widespread until the 1950s. Today, lumbar discectomy is one of the most commonly performed elective operations in the United States. ProblemLumbar disc disease is a rather encompassing term. For example, some physicians include back pain alone as a symptom of disc disease. Others make the diagnosis without evidence of disc disease on MRI. The discussion of this article is limited to well-defined lumbar disc herniation. The pathophysiology, clinical presentation, radiographic diagnosis, treatment, and outcome are discussed. FrequencyAlthough most people experience back pain during their lifetime, only a fraction experience lumbar radiculopathy or sciatica as a consequence of root compression or irritation. Almost 5% of males and 2.5% of females experience sciatica at some time in their lifetime. EtiologyA herniated disk fragment comes from the nucleus pulposus of the disc (a remnant of the embryonic notochord). In the normal condition, this nucleus is in the disk center securely contained by the annulus fibrosus. When a fragment of nucleus herniates, it irritates and/or compresses the adjacent nerve root. This can cause the pain syndrome known as sciatica and, in severe cases, dysfunction of the nerve. ClinicalMost lumbar disc herniations are preceded by bouts of varying degrees and duration of back pain. In many cases, an inciting event cannot be identified. Pain eventually may radiate into the leg. It may be characterized as less achy, burning, or similar to an electrical shock and is often described as a shooting or stabbing pain. The distribution of the leg pain is somewhat dependent on the level of nerve root irritation. Higher herniations (third or fourth lumbar levels) can radiate into the groin or anterior thigh. Lower radiculopathies (first sacral level) cause pain in the calf and bottom of the foot. Fifth lumbar radiculopathy, which occurs most commonly, causes lateral and anterior thigh and leg pain. Often, accompanying numbness or tingling occurs with a distribution similar to the pain. Accompanying muscle weakness may be unrecognized if the pain is incapacitating. The pain usually improves when the patient is in the supine position with the legs slightly elevated. Patients are more comfortable when changing positions. Short walks can bring relief. Long walks or extended sitting (especially driving) can aggravate the pain. On examination, patients may be neurologically normal, may have a profound radiculopathy, or may even demonstrate a cauda equina syndrome. A positive straight-leg raising sign is almost always present. However, a crossed straight-leg raising sign may be even more predictive of a lumbar disc herniation. The back may appear scoliotic. Gait is often abnormal. Muscle weakness may be revealed particularly when testing walking on heels and toes. INDICATIONSSection 3 of 11
The indications for surgical treatment of symptomatic lumbar disc disease are not clearly delineated. Nevertheless, situations exist in which most spine surgeons would probably agree on operative intervention. These situations include the following:
Notably missing from this list is a patient presenting with a profound motor deficit of varying duration. In the absence of pain, whether such patients benefit from surgery is unclear. No consensus has been reached concerning how urgent surgery is for a patient who presents with a clinical picture of painful disk herniation. Unfortunately, the decision to operate emergently is often based on fear of legal repercussions rather than on scientific evidence of actual patient benefit. RELEVANT ANATOMYSection 4 of 11
A disc herniation most frequently irritates the displaced nerve root. One of the more difficult concepts for beginning medical students to grasp is the anatomic relationship of the fifth lumbar (L5) nerve root to the L4-5 disc herniation. Equally important to understand is the concept of the far lateral or foraminal disc herniation in which the root above the disc herniation is irritated. With very large herniations, the entire cauda equina can be compressed and functionally compromised. This causes saddle anesthesia and can cause urinary retention and incontinence. CONTRAINDICATIONSSection 5 of 11
Any claim of absolute contraindication would invariably be challenged. Most spine surgeons adhere to some guidelines, including the following:
WORKUPSection 6 of 11
Imaging Studies
Other Tests
Histologic FindingsSome surgeons continue to submit disc material for histologic diagnosis. The yield of this is exceedingly low and of questionable benefit. TREATMENTSection 7 of 11
Medical therapyAlmost all patients with sciatica and disc herniations deserve a trial of medical therapy. The one obvious exception is a patient presenting with cauda equina syndrome or profound motor deficits. Most practitioners are well versed in the initial management of cases of sciatica. Counseling and education about the disease helps the patient commit to a successful trial of nonoperative management. Encourage bedrest and prescribe anti-inflammatory agents (steroidal and/or nonsteroidal) with analgesics that are sufficiently strong enough to relieve pain. Muscle relaxants aid in relieving associated muscle spasm. After 7-14 days, slow mobilization is started. Once the patient has recovered from the worst radicular pain, physical therapy can be instituted. Return to work (either limited or full) is important at this point. Stop steroidal medications. Reevaluate patients about a month after the onset of sciatica. At this time, studies can be ordered or a more intense back rehabilitation program can be designed so appropriate referrals can be made. Epidural steroid injections can be employed at almost any time. Surgical therapyWhat constitutes surgical therapy is open to discussion. The standard lumbar microdiscectomy has numerous variations, one of which is outlined below. Percutaneous discectomies are still performed frequently. Lately, endoscopic techniques have gained in popularity. Chemonucleolysis, although in principle an excellent alternative, is no longer performed. Other procedures, such as thermal ablation, are also performed. Preoperative detailsA complete workup is essential. Based on the patient's age group and comorbidities, perform the appropriate laboratory examinations, radiographic examinations, and further tests, as needed, to ensure a safe anesthetic period. Intraoperative detailsThe standard lumbar microdiscectomy is described. Variations in technique exist between institutions, regions, and surgeons. The patient is anesthetized and placed in the prone position. The hips are flexed to open the interlaminar spaces. A protuberant belly should hang as freely as possible to reduce venous hypertension. The ulnar nerves at the elbow are padded to prevent neuropathy. The legs cannot be overflexed. The back is parallel to the ground. A preoperative radiograph with a spinal needle is obtained to confirm localization. The back is shaved and prepared. After injection of a long-acting local anesthetic agent, a 3-cm incision is made over the disc space (as determined by radiograph). Unipolar cautery is used to dissect down through midline subcutaneous fat. The lumbodorsal fascia is opened paramedially. Muscles are stripped from the lamina. Obtain a repeat radiograph to confirm the appropriate location. A small laminotomy is created with a drill or rongeurs. The ligament is excised with rongeurs or a knife. An operating microscope is now used. The medial facet is partially resected in most patients. The root is then identified and retracted. The disc fragment is evident below the retracted root. The annulus is incised and the disc removed with pituitary rongeurs. Remove loose fragments of the disc in the space. Palpate the course of the nerve root with an angled instrument along its entirety to ensure adequate decompression. Bleeding is stopped, the wound is irrigated, and then it is closed in interrupted absorbable sutures layer by layer. A light dressing is applied. Postoperative detailsThe patient is treated with oral narcotics and IV supplementation for pain. Antiemetics are administered as needed. The patient is mobilized 4-6 hours after surgery and should be able to void without help. Once the patient tolerates fluids, he or she may leave the hospital with an ample supply of narcotics, antispasmodic agents, and stool softeners. Rarely, the patient may remain in the hospital 24 hours after the operation. Follow-upThe patient is seen in follow-up one month after surgery. For uncomplicated cases, the patient is then released from the surgeon's care. The patient is usually released to work 6-10 weeks postoperatively, depending on the occupation. COMPLICATIONSSection 8 of 11
The overall complication rate is 2-4% for the surgery. Despite endless reports of misadventures, surgeons still operate on the wrong level. Therefore, reliance on intraoperative radiographic confirmation of the intended level is strongly encouraged. Bleeding intraoperatively can be copious and is almost invariably due to malpositioning. Engorged venous epidural channels can make the operation more difficult and far more dangerous. Very rarely, the anterior annulus is violated and a retroperitoneal vessel is injured. Awareness of this complication is essential. Should this occur, the back is closed while a vascular surgeon prepares to repair the vessel via laparotomy. Infections, usually skin infections, can occur. The authors' protocol is to administer one dose of a preoperative antibiotic within one hour of surgery. Very rarely, postoperative discitis can cripple a patient who is recovering. Suspect discitis in the setting of an increasing sedimentation rate, fevers, severe localized pain, and recurrent symptoms. Increased neurologic deficit is usually mild and is due to excessive retraction of the root. If a nerve root is mistaken for a disc herniation and is removed, the resultant injury can be severe. If possible, identify the root and disc in the same field. On occasion, a conjoined root can add significant technical complexity to the case. OUTCOME AND PROGNOSISSection 9 of 11
Almost every study measures the outcome from lumbar disc surgery differently. A good outcome may be defined as the decreased use of narcotics, prompt return to work, or reported reduction in pain. Understandably, outcome studies can be misinterpreted or misrepresented. Approximately 75% of patients who undergo a microdiscectomy have long-term reduction of sciatic pain and, thus, are considered cured. Reported results vary from 65-95%. Predominance of leg pain is the best determinant of good outcome from surgery for lumbar disc herniation. Unfortunately, a rather large fraction of individuals who have had surgery for lumbar disc disease have recurrent or residual pain, which can be a significant challenge to treat. A methodical postoperative evaluation is necessary, focusing on symptom clarification, careful examination, and repeat radiographic examinations and MRI with contrast. Also, some patients who are surgically treated are more prone to further problems such as recurrent herniations, arachnoiditis, and vertebral instability. FUTURE AND CONTROVERSIESSection 10 of 11
Most areas of controversy are delineated within the above text. The major controversies are outlined in this section. The duration of conservative management has been debated since the disease was identified. As surgical treatments become less invasive and medications change, the role and duration of conservative management will change as well. Endoscopic operations are becoming safer and more prevalent. Although many microdiscectomies are now being performed in the outpatient setting, the impetus for even less invasive procedures continues. The role of stabilization in lumbar disc surgery is very unclear. An increasing number of patients are having extensive fusions as the first-line management of lumbar radiculopathy secondary to disc herniations. However, the indications for stabilization need to be better established. REFERENCESSection 11 of 11
Article Last Updated: Jun 23, 2006 |
