eMedicine Specialties > Neurosurgery > Spine

Lumbar Disc Disease

Kamran Sahrakar, MD, FACS, Clinical Professor, Department of Neurosurgery, University of California at San Francisco
Martin Melicharek, MD, Assistant Clinical Professor, Department of Neurosurgery, University of California at Davis

Updated: Nov 4, 2009

Introduction

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.

Degenerative lumbar disc disease. The various forces placed upon the discs of the lumbar spine that can result in degenerative changes.

History of the Procedure

The 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.

Problem

Lumbar 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.

Frequency

Although 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.

Etiology

A 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.

Presentation

Most lumbar disc herniations (lumbar disc diseases) 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 (lumbar disc disease). The back may appear scoliotic. Gait is often abnormal. Muscle weakness may be revealed particularly when testing walking on heels and toes.

Indications

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:

A patient with cauda equina syndrome
A patient demonstrating progressive neurologic deficit during a period of observation
A patient with persistent bothersome sciatic pain, despite conservative management, for a period of 6-12 weeks (a time period that varies from surgeon to surgeon)

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 Anatomy

A disc herniation (lumbar disc disease) 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.

Contraindications

Any claim of absolute contraindications for lumbar disc disease would invariably be challenged. Most spine surgeons adhere to some guidelines, including the following:

A patient with unrelenting back pain: Patients who have back pain after a bout of sciatica has resolved are not good candidates for operative treatment. Often, these patients are the most insistent and difficult to manage. Occasionally, these are patients whose back pain improved after discectomy for a large central disc herniation.
A patient with an incomplete workup: When diagnosis is uncertain, postpone surgery. Disc herniations are so ubiquitous that being cavalier in diagnosis is easy. Ensure the completeness of the workup prior to proceeding with the operation. All surgeons can recall several cases in which a diabetic plexopathy or an epidural metastasis was missed.
A patient not provided adequate conservative treatment: Spine surgeons rarely commit a patient with a short period of sciatica and without bedrest and a steroid trial to an operation that will permanently alter the patient's back mechanics and strength.

Workup

Imaging Studies

MRI is by far the most commonly ordered test to evaluate patients with sciatica.
- Often, MRI is performed prior to plain radiographs.
- MRI is very sensitive in delineating lumbar disc herniations. Far lateral discs are best evaluated with this test.
- In reoperations, MRI can delineate the full extent of scar tissue and, with moderate reliability, differentiate it from recurrent disc herniation.
CT scan myelography may be preferred by surgeons for evaluating patients before reoperation or for evaluating patients who have severely spondylotic changes. This is because CT scan myelography can delineate bony structures better than MRI.
Plain radiographs, especially with weight-bearing flexion and extension views, can be a useful adjunct to other radiographic evaluations. Some spine tumors, instabilities, malalignments, and congenital anomalies can be identified best with plain radiographs. Obtain plain films on all patients prior to surgery.

Other Tests

Electromyography is rarely helpful in the diagnosis or management of lumbar disc disease. Occasionally, a diabetic patient can be identified as having a polyradiculopathy or plexopathy. On this basis, some surgeons proceed to surgery with more caution.

Histologic Findings

Some surgeons continue to submit disc material for histologic diagnosis. The yield of this is exceedingly low and of questionable benefit.

Treatment

Medical Therapy

Almost 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.

The success of conservative management of lumbar disc herniations may depend on the type of herniation. A review of over 600 patients concluded that noncontained herniations may respond more successfully to nonsurgical treatment.¹

Epidural steroid injections can be used at almost any time.

Surgical Therapy

What 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. This method appears more applicable in small and contained disc herniations.² Chemonucleolysis, although in principle an excellent alternative, is no longer performed. Other procedures, such as thermal ablation, are also performed.

Preoperative Details

A 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 Details

The 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. Some evidence indicates that joint angles smaller than 35° result in resection of larger portions of the medial facet and result in more immediate postoperative pain.³ 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. Loose fragments of the disc in the interspace are removed. The course of the nerve root is palpated with an angled instrument along its entirety to ensure adequate decompression. Significant controversy exists regarding the optimal extent of discectomy.⁴ 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 Details

The 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-up

The 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.

Complications

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 Prognosis

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.

Interestingly, a 2006 large multicenter trial found that surgical and nonsurgical outcomes at 2 years were similar, but that the surgical group experienced faster pain relief.^5,6 The limitations of this study are outlined in a more recent editorial.⁷

Also, some patients who are surgically treated are more prone to further problems such as recurrent herniations, arachnoiditis, and vertebral instability.

Future and Controversies

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. In fact, the endoscopic approach is even used in the traditionally more technically demanding recurrent cases.⁸

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.

Multimedia

Media file 1: Degenerative lumbar disc disease. The various forces placed upon the discs of the lumbar spine that can result in degenerative changes.

References

Nakagawa H, Kamimura M, Takahara K, et al. Optimal duration of conservative treatment for lumbar disc herniation depending on the type of herniation. J Clin Neurosci. Feb 2007;14(2):104-9. [Medline].
Mirzai H, Tekin I, Yaman O, et al. The results of nucleoplasty in patients with lumbar herniated disc: a prospective clinical study of 52 consecutive patients. Spine J. Jan-Feb 2007;7(1):88-92; discussion 92-3. [Medline].
Celik SE, Celik S, Kara A, et al. Lumbar facet joint angle and its importance on joint violation in lumbar microdiscectomy. Neurosurgery. Jan 2008;62(1):168-72; discussion 172-3. [Medline].
Eugene J. Carragee, MD, Anthony O. et al. A Prospective Controlled Study of Limited VersusSubtotal Posterior Discectomy: Short-Term Outcomesin Patients With Herniated Lumbar Intervertebral Discsand Large Posterior Anular Defect. Spine. 2006;31:653-657.
[Best Evidence] Weinstein JN, Tosteson TD, Lurie JD, et al. Surgical vs nonoperative treatment for lumbar disk herniation: the Spine Patient Outcomes Research Trial (SPORT): a randomized trial. JAMA. Nov 22 2006;296(20):2441-50. [Medline].
Weinstein JN, Lurie JD, Tosteson TD, et al. Surgical vs nonoperative treatment for lumbar disk herniation: the Spine Patient Outcomes Research Trial (SPORT) observational cohort. JAMA. Nov 22 2006;296(20):2451-9. [Medline].
Mazanec D, Okereke L. Interpreting the Spine Patient Outcomes Research Trial. Medical vs surgical treatment of lumbar disk herniation: implications for future trials. Cleve Clin J Med. Aug 2007;74(8):577-83. [Medline].
Hoogland T, van den Brekel-Dijkstra K, Schubert M, et al. Endoscopic transforaminal discectomy for recurrent lumbar disc herniation: a prospective, cohort evaluation of 262 consecutive cases. Spine. Apr 20 2008;33(9):973-8. [Medline].
Bussieres AE, Taylor JA, Peterson C. Diagnostic imaging practice guidelines for musculoskeletal complaints in adults-an evidence-based approach-part 3: spinal disorders. J Manipulative Physiol Ther. Jan 2008;31(1):33-88. [Medline].
Resnick DK, Choudhri TF, Dailey AT, Groff MW, Khoo L, Matz PG, et al. Guidelines for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 2: assessment of functional outcome. J Neurosurg Spine. Jun 2005;2(6):639-46. [Medline].
Ehni BL, Benzel EC. Lumbar Discectomy. Spine Surgery. 1999;1:389-400.
Hardy RW. Extradural Cauda Equina and Nerve Root Compression from Benign Lesions of the Lumbar Spine. Neurological Surgery. 1996;3:2357-2374.
Loupasis GA, Stamos K, Katonis PG, et al. Seven- to 20-year outcome of lumbar discectomy. Spine. Nov 15 1999;24(22):2313-7. [Medline].
Williams RW. Lumbar disc disease. Microdiscectomy. Neurosurg Clin N Am. Jan 1993;4(1):101-8. [Medline].
Woertgen C, Rothoerl RD, Breme K, et al. Variability of outcome after lumbar disc surgery. Spine. Apr 15 1999;24(8):807-11. [Medline].

Keywords

lumbar disc disease, disc herniation, herniated disc, degenerative disc disease, lumbar disc, lumbar degenerative disc disease, lumbar disk disease, degenerative disc, lumbar spine disc disease

Contributor Information and Disclosures

Author

Kamran Sahrakar, MD, FACS, Clinical Professor, Department of Neurosurgery, University of California at San Francisco
Kamran Sahrakar, MD, FACS 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
Disclosure: Nothing to disclose.

Coauthor(s)

Martin Melicharek, MD, Assistant Clinical Professor, Department of Neurosurgery, University of California at Davis
Martin Melicharek, MD is a member of the following medical societies: American Association of Neurological Surgeons, California Medical Association, and Ohio State Medical Association
Disclosure: Nothing to disclose.

Medical Editor

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 of New Jersey
Michael G Nosko, MD, PhD is a member of the following medical societies: Academy of Medicine of New Jersey, Alpha Omega Alpha, American Association of Neurological Surgeons, American College of Surgeons, American Heart Association, American Medical Association, New York Academy of Sciences, and Society of Critical Care Medicine
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment

Managing Editor

Allen R Wyler, MD, Former Medical Director, Northstar Neuroscience, Inc
Allen R Wyler, MD is a member of the following medical societies: American Academy of Neurological and Orthopaedic Surgeons, American Association of Neurological Surgeons, and Society of Neurological Surgeons
Disclosure: Nothing to disclose.

CME Editor

Paolo Zamboni, MD, Professor of Surgery, Chief of Day Surgery Unit, Chair of Vascular Diseases Center, University of Ferrara, Italy
Paolo Zamboni, MD is a member of the following medical societies: American Venous Forum and New York Academy of Sciences
Disclosure: Nothing to disclose.

Chief Editor

Further Reading

Clinical guidelines

Bussieres AE, Taylor JA, Peterson C. Diagnostic imaging practice guidelines for musculoskeletal complaints in adults-an evidence-based approach-part 3: spinal disorders. J Manipulative Physiol Ther 2008 Jan;31(1):33-88.⁹

Resnick DK, Choudhri TF, Dailey AT, Groff MW, Khoo L, Matz PG, Mummaneni P, Watters WC 3rd, Wang J, Walters BC, Hadley MN, American Association of Neurological Surgeons/Congress of Neurological Surgeons. Guidelines for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 2: assessment of functional outcome. J Neurosurg Spine 2005 Jun;2(6):639-46.¹⁰