Surgery for Back and Neck Pain (Including Radiculopathies)

SUMMARY

The field of surgery for spinal disease is currently growing faster than any other surgical area. Thus, it is extremely important to understand the indications for surgery and the appropriate application of surgical procedures for these diseases of the spine. Most acute spinal pain states will relent spontaneously, no matter what the cause. The surgeon must always be alert for red flags that indicate intercurrent disease. The time-honored approach to spinal pain has included an obligatory trial of physical therapy and pain-relieving measures. However, there is little evidence that any of these interventions will provide a significant change in the natural history of expected recovery or do more than give the patient temporary relief. My own approach to acute spinal pain without significant neurological deficit is to provide time to heal, adequate analgesia during the healing period, and restriction from activities that might aggravate the process.

Surgery is a viable alternative when pain is intractable or a serious neurological deficit has occurred. The history alone usually provides an adequate diagnosis. The presence or absence of neurological signs and symptoms may be important for determining the choice and timing of therapy. Imaging studies define the spinal problem with great accuracy. There has been a revolution in spinal surgery in the past decade, with enormous advances in the technical aspects of disc replacement, spinal realignment, and spinal fixation.

The outcome of spinal surgery depends entirely on the disease to be treated. Patients with simple disc herniation, single-level root compression, or multilevel spinal cord or cauda compression can all be expected to do extremely well following surgery. Adequate pain relief will occur in more than 90% of patients. Most will recover lost neurological function, and virtually everyone will return to all previous activities without restrictions. Patients with clear-cut root compression syndromes or demonstrated spinal instability who are selected by experts in spinal disease to undergo proven operative procedures can expect an excellent outcome most of the time but must understand that serious complications can occur.

Introduction

Pain is the most common reason for surgery on the back or neck, but pain alone is an insufficient reason to perform surgery. To understand the appropriate use of surgical procedures for back and neck pain it is necessary to understand that surgery corrects only one of two conditions. Surgical procedures can be designed to relieve compression on nerves or the spinal cord, and they can stabilize dynamically unstable motion segments (Bohannon and Gajdosik 1987, ). The key in the surgical decision-making process is not only to make a diagnosis but also to determine whether the patient has anatomical abnormalities amenable to surgical correction.

Only a small minority of patients in virtually all the disease categories that will be discussed will ever require surgery ( , ). Surgery should be considered in two situations:

Patients whose acute symptoms are too serious to be tolerated, including those with significant neurological deficits and/or intractable pain
When the potential for recovery within the known natural history of the disease has been exhausted, alternative forms of treatment have been ineffective, and the symptoms are a serious enough interference in the patient’s life to warrant the risks associated with surgery

The majority of acute back and neck pain syndromes relent spontaneously without treatment in a reasonable period ( , ). Since watchful waiting with adequate pain control is all that is required for the majority of patients, it should not be surprising that the principal classification used for both back and neck pain is temporally based rather than being focused on causes, pathologies, or treatments ( , ).

New basic research, however, strongly suggests that this time-honored approach to surgery may be insufficient. Laboratory data indicate that the inflammatory processes that occur with disc herniation or injury may excite nociceptors locally and even cause significant neuronal changes in the dorsal root ganglia and substantia gelatinosa. These findings may offer an explanation for why local anti-inflammatory drugs are frequently helpful to patients with herniated lumbar and cervical discs. The implications for surgery are as yet unknown.

Acute Pain

Acute back or neck pain is of two types. The first is termed transient and generally relents within a few hours or a few days. Such patients rarely seek medical intervention. The more typical acute back or neck syndrome lasts days to weeks and may even stretch into a few months. The symptoms may be very severe and neurological deficits may be present. In the absence of unbearable pain or a significant neurological deficit, watchful waiting is all that is required. Patients are treated with adequate analgesics, placed at rest for a few days until the symptoms begin to abate, and then returned to reasonable function as quickly as possible. Virtually all agree that these guidelines will lead to spontaneous recovery for most patients. In the absence of red flags, imaging is not required, and for the majority of patients with acute back and neck syndromes, no cause is ever determined.

Persistent Pain

We have recently identified a new category that we have termed persistent pain syndrome ( , ). These patients may have either back or neck pain and constitute a group who simply do not recover from the original acute pain syndrome. Even though they do not recover, they exhibit none of the characteristics of the so-called chronic pain syndrome. They remain functional, although function may be limited. Psychological abnormalities do not develop. They are refractory to the usual conservative treatments and the symptoms persist. The symptoms remained more or less constant over a period of 2–5 years in patients reported from our prospective large study.

Chronic Pain

The so-called chronic pain syndrome is characterized by chronicity of the pain complaints and is often complicated by depression, demoralization, misuse of analgesic medications, and a focus on pain and disability that is out of character with the physical impairments. These patients are quite different from those we have termed persistent, although they are indistinguishable in terms of physical causes ( ). The majority of patients undergoing surgery comes from the persistent pain category.

Chronic back pain, often with associated leg pain, is the most common medical complaint in developed countries ( ). The cost associated with back pain is enormous ( ; ). Back pain is one of the most frequent reasons why patients see physicians and one of the most common reasons for secondary referral, and both operative and non-operative treatment of back pain ranks high in terms of total expenditure of health care dollars ( , , ).

Causes and Treatment

Despite the obvious importance of back and neck pain as a complaint, the causes are poorly understood and few treatments have been validated ( ). A major issue is that the actual pathophysiological causes of the complaints are mostly unknown ( , , ). It has been estimated that only about 10% of patients with acute and chronic pain complaints have definable causes that can be clearly related to the complaint of pain. It is well validated that degenerative and spondylotic changes, no matter how severe, do not correlate well with pain complaints.

There is reasonable evidence that overt instability causes pain and that elimination of the instability will reduce the pain ( ). The strongest evidence is that root compression is associated with pain and neurological deficits ( , ). Decompression is satisfactory treatment for the majority of patients ( ). However, these two conditions are relatively rare in the spectrum of patients with back or leg pain complaints, and for the majority the association of complaints with demonstrated structural abnormalities is tenuous at best ( ).

It is not surprising that therapies are problematic in a condition without known causes of the pain ( , , ). Until there is a better scientific basis for understanding spinal pain and its treatment, we must use what is known to decide on the best current therapy for these patients ( ; ; ).

To reach supportable decisions concerning the evaluation and treatment of these patients, the physician involved in their care must have an organized classification framework in which to work ( Box 71-1 ). Knowing what the various diagnostic tests available can be expected to demonstrate is important. Rigorous evaluation of claims of therapeutic efficacy for all modalities of treatment is required. It is also important to have an equally rigorous understanding of outcome measurement to assess these claims ( , ).

Box 71-1

Temporal Classification of Low Back Pain with or without Sciatica

Transient

Self-limited with a duration of hours to days; comes to medical attention when episodic

Acute

Self-limited, but protracted with a duration of days to weeks; often seen by physicians; treatment is symptomatic; most recover spontaneously; evaluation and treatment required for severe symptoms

Persistent

Lasts more than 3–6 months; does not relent with time; high correlation with spondylotic disease; no psychological co-morbid conditions; surgical intervention occurs mostly in this group

Chronic (Pain Syndrome)

Lasts more than 6 months and worsens with time; associated with major co-morbid conditions, especially psychological; multidisciplinary therapy commonly required

The goal of this chapter is to provide a framework for the evaluation, diagnosis, choice of treatment, and assessment of treatment outcome for patients complaining of chronic low back pain with or without sciatica or neck pain and with or without a radicular component with a focus on selection criteria for surgery and outcomes of common surgical procedures.

Diagnosis of Spinal Pain

Evaluation of Spinal Pain

History

The evaluation should begin with a careful history that describes the severity and location of the pain and its triggers ( ; ). Physical examination is unlikely to be diagnostic but will assess the patient’s neurological and musculoskeletal abnormalities. Routine neurological examination is needed as a baseline at least ( ).

During these examinations listen for danger signals such as night pain (intraspinal tumor), constant pain (cancer or infection), systemic symptoms (cancer or infection), and symptoms of other organ or systemic disease ( ).

Also, observe the patient’s behavior during the examination. Is there much pain behavior? Are the patient’s actions consistent with the complaints? Are the results of motor examination reliable ( , , )?

Unlike acute pain problems, imaging is important in patients with persistent pain ( ). Plain flexion–extension films are important. Magnetic resonance imaging (MRI) is best for most screening ( ). Computed tomography (CT) can be used if bony pathology is suspected; with two- and three-dimensional reconstructions, fixator artifacts can be reduced ( , ). CT myelography is needed rarely, most commonly in patients with previous surgery ( , , , ).

There is no need for psychological testing unless symptoms suggestive of psychiatric disturbance are present ( , ).

In a recent study we demonstrated that expert spinal surgeons almost always made an accurate diagnosis on the basis of the history alone. The key elements are the temporal and special characteristics of the pain, as well as its severity. Other associated neurological complaints may be present, but they are not required and are not usually very serious impairments ( , ).

Physical Examination

Physical examination is not nearly as important in patients with spinal pain as in many other areas of neurological practice ( , ). When typical, it is useful to localize an abnormality, but most patients do not have focal physical findings. The classic combinations of reflex, motor, and sensory changes described in texts are relatively rare. In a study of nearly 3000 patients, we demonstrated such classic combinations in less than 1% ( , ).

Range of motion of the part of the spine at which the pain is located, the presence or absence of muscle spasm, local areas of tenderness and other local non-specific signs of abnormality, strength, sensation, and reflexes should all be assessed in the standard way. Straight-leg raising is the only physical sign of great value in patients with lumbar disc disease. It is positive in the majority of patients, and the crossed straight-leg raising test is strongly indicative of a root compression syndrome. There is no similar test for cervical disc herniation. The important function of the physical examination is to determine the presence or absence of neurological loss and the severity of these deficits ( ).

Cervical myelopathy is of particular concern. Cervical spinal cord compression is a serious issue that usually requires surgery. When cervical pain is the complaint, careful examination for myelopathy is important. Spinal cord compression should be signaled by increased reflexes; presence of the Hoffman and Babinski signs; bilateral loss of motor power, particularly grip strength and walking stability; and patchy sensory loss without a typical sensory level.

Imaging Diagnosis

Evaluation begins with plain films of the affected area of the spine, including dynamic films. If simple disc herniation or spinal stenosis is suspected, MRI should be diagnostic. It would be the only test needed for the large majority of patients. If significant bony abnormalities are suspected, however, CT is useful. When neither a diagnostic image nor the clinical syndrome is typical, CT myelography can still be a useful study ( ).

Electrodiagnostic Studies

Such studies are helpful in several instances, but they are rarely indicated in patients with typical disc herniation. Electromyography is most useful in differentiating peripheral neuropathies and entrapment neuropathies from obscure root compression syndromes. Neurophysiological studies can also be used to verify cauda or spinal cord compression.

Provocative Blocks

In indeterminate cases, diagnostic provocative blocks are often important ( , , ). The hypothesis is the same for all: elimination of the pain component by anesthetization of a particular structure suggests that the structure is involved as a pain generator. A further part of the study is usually provocation of the patient’s individual pain syndrome by needling or by injection. The combination of the two is considered the most concordant. Structures commonly blocked include nerve roots, zygapophyseal joints, and discs. A positive result means that the patient’s pain was mimicked by the procedure and relieved during the short period of anesthetization. Placebo blocks are required to achieve high specificity and selectivity.

These blocks should never be depended on as an indication for surgery alone. Rather, they are part of the overall patient assessment and may add some information implicating a particular vertebral segment as a pain generator ( ). To achieve validity, the location of the needles must be verified.

Provocative discography has now been demonstrated to have predictive value for spinal arthroplasty and fusion.

Causes of Spinal Pain

Another way to categorize surgical patients with chronic back and neck pain is to list the causes that may lead to surgery. Most experts agree that the preponderance of these patients have spondylotic disease, which is at least associated with the pain problem if not yet proved to be causative ( , , ) ( Box 71-2 ).

Box 71-2

Causes of Chronic Back and Leg Pain

As a Symptom of Intercurrent Disease

Bone or spinal cord tumor
Lumbar metastases
Lumbar spinal infection
Retroperitoneal inflammation
Renal disease
Aortic aneurysm
Endometriosis
Abdominal or pelvic cancer

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