This article outlines the role of spinal cord stimulation in contemporary chronic pain management. The anatomical and neurophysiological correlates of stimulation of the intraspinal structures are discussed. The most common indications are presented, including failed back syndrome, reflex sympathetic dystrophy, neurogenic thoracic outlet syndrome, and spinal cord injury, etc. The most common complications are presented, including paralysis, infection, electrode migration, cerebrospinal fluid leak, and pain. Spinal cord stimulation is one of the most effective techniques available in the management of severe chronic pain that has been refractory to other more conservative modalities.
In medical practice, each time span has a dogma of that period. Now, in the science and technology age, one particular dogma is very extensively accepted and used in pain practice. There is a general belief in neurosurgical practice that lesioning of the pain conducting system is accepted as ablative and dangerous. This idea is a dogma and it is wrong. In modern times, modern stereotactic pain surgery is performed in three important steps. First, morphology and localization of the pain conducting pathways are demonstrated with special imaging techniques; the surgeon approaches the target percutaneously by a specially designed needle electrode system. Second, the function of the target and surrounding structures can be defined by stimulation just after the target is totally, partially, or selectively destroyed by radiofrequency lesion. Third, lesioning of the system is controlled at every step of the procedure. These procedures are applied with morphological real-time demonstration, physiological evaluation of the target, and, finally, controlled lesioning. In this way, this surgery is performed safely and effectively. In this paper, I describe the techniques of this method based on a 17-year experience with three different stereotactic destructive procedures: CT-guided percutaneous cordotomy, trigeminal tractotomy, and extralemniscal myelotomy.
In many patients with chronic pain there is often a disparity between the degree of analgesic relief claimed by the patient and the ability to function better. The reasons for this are presented in a construct that suggests areas for consideration in any patient who is being considered for chronic analgesic use. Issues that influence perceived benefit are outlined. The importance of drug tolerance, dosage compliance, and patient's involvement in treatment are stressed. The use of contracts as an integral part of documented patient participation is outlined. Mechanisms that help in the handling of difficult patients are described. The use of physician extenders, anticipation of inappropriate patient behaviors, and prior expression of sanctions are shown to be helpful. The use of medications as part of the multidimensional care of the patient with chronic pain is discussed. This article presents practical solutions for difficulties encountered in managing patients with chronic pain.
Classic, idiopathic trigeminal neuralgia is an easily recognizable condition of excruciating, lancinating pain in one or more of the trigeminal distributions. Atypical features may exist (i.e., constant burning pains of a background nature) and we propose this condition represents the natural progression of trigeminal neuralgia type 1 to type 2. The etiology of trigeminal neuralgia is accepted as occurring from microvascular compression at the root entry zone, but other trigeminal facial pain syndromes exist and occur from iatrogenic (trigeminal deafferentation pain) or traumatic (trigeminal neuropathic pain) injuries. It is important to recognize when facial pain occurs in cranial nerve distributions other than the trigeminal nerve, as the treatments are different for geniculate, glossopharyngeal, and occipital neuralgia. Lastly, atypical facial pain occurs in a nonanatomic distribution and may be attributed to nonorganic or psychological causes. Pain from the facial sinuses, odontologic pain, and temporal mandibular joint pain are discussed.
This first of two issues of Seminars in Neurosurgery on pain management for the neurosurgeon is split roughly between two broad topics: fundamentals and specific syndromes.
The control of chronic intractable pain has been a challenge to neurosurgeons for decades. Over the last 30 years there has been a shift in treatment paradigms from ablation to neuroaugmentation therapies. Surgical ablative treatments have in common the risk of motor system deficits and delayed deafferentation pain. In recent years, electrical stimulation and intrathecal drug delivery have become the favored interventional treatments for chronic benign pain syndromes. The use of electrical stimulation on the human brain to modulate pain dates back to the 1950s. Paramount to obtaining a good outcome with deep brain stimulation (DBS) is the proper selection of a patient and a correct target. In contemporary times, selection of patients for DBS procedures should be limited to those who experience neuropathic pain syndromes and more specifically complain of constant, steady burning or aching pain. These patients must first be considered for stimulation at other sites, such as spinal cord, nerve root, or peripheral nerve. Patients who have had trials with one of these other targets may have failed to respond for a variety of reasons. If the failure has been due to an inability to produce an overlap of paresthesia on the pain segment, the patient may be considered a candidate for DBS. Other reasons for failure of the previously attempted targets are likely to predict failure of DBS as well.
Successful management of chronic pain disorders and diseases starts with an appreciation of the many biological and psychosocial factors, including pain generators and comorbidities, that may affect outcome. Choosing the appropriate treatment for any one patient hinges on a careful assessment of these factors and a reasoned and feasible outcomes-oriented treatment plan that controls as much of the variance as possible. Chronic pain, a coping challenge for everyone, causes some psychosocial problems for everyone and clinically significant psychiatric disorder in many. Or, chronic pain onset can worsen preexisting psychosocial problems and psychiatric disorders. Simple screening questions are highly sensitive, missing few cases. Specific diagnosis requires a more detailed interview. Suicide is the most common mortal complication of chronic pain, particularly with comorbid depression, and should be asked about routinely. Depression, anxiety disorders, and substance abuse are the most common complicating psychiatric comorbidities. These should be identified and managed to achieve optimal surgical outcomes. A plethora of effective medications, some for specific depression and anxiety disorder diagnoses, are available. Substance abuse and addiction are more difficult and may require special treatments. Skillfully treating both pain and psychiatric comorbidity leads to the best functional outcomes for the person in pain.
Glossopharyngeal neuralgia (GPN) is a pain syndrome characterized by attacks of severe pain in the sensory distribution of the glossopharyngeal nerve. Most cases of GPN respond to treatment with carbamazepine and other anticonvulsants. The causative element of essential GPN appears to be a vascular compression of the glossopharyngeal nerve root and the upper rootlets of the vagus nerve; therefore, the most definitive surgical treatment consists of microvascular decompression of the ninth (and tenth) nerve in the posterior cranial fossa. In cases of secondary GPN and when microvascular decompression is not possible, intracranial rhizotomy of the glossopharyngeal and upper portion of the vagal nerve roots may be the next logical step in surgical management. Extracranial neurotomy and percutaneous radiofrequency rhizotomy are useful for patients with GPN who have failed medical treatment but for some reason cannot undergo intracranial intervention.
Although medical therapy is of benefit to many patients with trigeminal neuralgia, surgical management is often performed for patients with medically refractory pain. Gamma knife radiosurgery has been advocated as a minimally invasive alternative surgical approach to microvascular decompression or percutaneous surgeries. In this article, we review the safety and efficacy of this technique and discuss potential ways to improve on results.
The realization that chronic pain and acute pain might have different mechanisms has led to important developments in both research and patients' care. Basic research paradigms that focus upon long-term changes in tissues and the nervous system have led to useful models for chronic pain. Clinical research has shown that strategies effective for acute pain often fail in patients with chronic pain and that there is utility in the cognitive-behavioral approach to the management of patients with chronic pain. We discuss the history and implementation of comprehensive multidisciplinary pain diagnosis and treatment. We conclude with a review of the data on outcomes and cost-effectiveness for multidisciplinary pain management.
Intracranial stereotactic procedures in the central nervous system for the treatment of medically refractory chronic pain have evolved over the years. Neuroablative lesions have become a rare treatment for chronic pain, primarily because of the advent of more effective pharmacotherapy and intrathecal drug delivery. Lesion generation has the advantage of being less costly and having none of the hardware-related side effects of deep brain stimulation but the disadvantage of not being modifiable or reversible when the lesion has been generated. Although neuroablative procedures typically result in short-lived pain relief and the possibility of deafferentation pain, these procedures are still useful in certain clinical settings. The indications, methods employed, and outcome for these procedures are covered in this article.
Percutaneous destructive procedures include radiofrequency rhizotomy, glycerol rhizotomy, and trigeminal balloon compression. These procedures are best offered to patients who cannot undergo microvascular decompression or gamma knife radiosurgery or who fail the latter procedures. They are especially utilized in elderly patients in poor medical condition and in the treatment of trigeminal neuralgia associated with multiple sclerosis.
First described in the 16th century, phantom limb pain (PLP) describes the painful sensations resulting from a lost body part, classically a lost limb. This article reviews the incidence, clinical course, pathophysiology, and current treatment options for PLP. The reported incidence of PLP varies widely from 0.5 to 90% because of sampling biases and the lack of differentiating PLP from stump pain or phantom sensations. The clinical course is rapid with symptoms typically occurring within the first week of limb loss and persisting for up to 2 years or more. Although both psychiatric and peripheral causes have been proposed, recent studies suggest a primary role of the central nervous system in the genesis of PLP. Treatment of PLP remains difficult, with no single modality sufficient to manage the pain. Optimal management currently involves a multidisciplinary approach involving physical treatments, pharmacologic intervention, and psychiatric therapy. Surgical options remain limited although novel interventions such as motor cortex stimulation may be beneficial.
First described in the 16th century, phantom limb pain (PLP) describes the painful sensations resulting from a lost body part, classically a lost limb. This article reviews the incidence, clinical course, pathophysiology, and current treatment options for PLP. The reported incidence of PLP varies widely from 0.5 to 90% because of sampling biases and the lack of differentiating PLP from stump pain or phantom sensations. The clinical course is rapid with symptoms typically occurring within the first week of limb loss and persisting for up to 2 years or more. Although both psychiatric and peripheral causes have been proposed, recent studies suggest a primary role of the central nervous system in the genesis of PLP. Treatment of PLP remains difficult, with no single modality sufficient to manage the pain. Optimal management currently involves a multidisciplinary approach involving physical treatments, pharmacologic intervention, and psychiatric therapy. Surgical options remain limited although novel interventions such as motor cortex stimulation may be beneficial.
In 1991 Tsubokawa and colleagues first published their landmark results from a series in which epidural motor cortex stimulation (MCS) was used in the treatment of eight patients with central and neuropathic pain. In ensuing studies authors have elaborated on the indications, technique, hypotheical mechanisms, and beneficial results of this treatment. Epidural MCS is effective for trigeminal neuropathy, lateral medullary and thalamic infarction, anesthesia dolorosa, postherpetic neuralgia, spinal cord injury, and limb stump pain. Postoperative outcomes are better when patients present with only mild or absent motor weakness in the region of pain and when there is pain in the trigeminal region. It is hypothesized that MCS is effective because it increases regional cerebral blood flow in the ipsilateral ventrolateral thalamus in which corticothalamic connections from the motor and premotor areas predominate. The extent of pain alleviation also correlates with the increase of blood flow in the cingulate gyrus. This suggests that stimulation reduces the suffering experienced by a patient with chronic pain. Procedure-related morbidity has included epidural hematoma, subdural effusion, gradual diminution of benefit, and painful stimulation. Although of concern, treatment-induced chronic seizure disorders have not occurred as a complication or in animal models of chronic cortical stimulation. Stimulation-induced pain relief occurs within minutes. There are no associated paresthesias or muscle contractions that confirm function. Pain relief may last for hours after electrical stimulation is discontinued. Motor cortex stimulation is an established therapy for the treatment of complex central and neuropathic pain syndromes that have proved refractory to medical treatment.
Pain following spinal cord trauma is common and frequently perplexing as multiple etiologies can confuse the diagnosis. Neuropathic pain from spinal cord damage is frequent, occurring in up to 40% of patients. However, autonomic and musculoskeletal pain generators are also common.
In this double issue of Seminars in Neurosurgery, our discussion of the surgical management of pain focuses on procedures. Our investigations are devoted to the theoretical basis of the various procedures covered, patient selection, technical aspects of the procedures, and expected outcomes.
Postherpetic neuralgia (PHN) is a chronic neuropathic pain syndrome defined as pain persisting more than 3 months after the resolution of herpes zoster-associated rash. It is often characterized as spontaneous aching or burning with paroxysmal shooting pains in the affected dermatome and may be accompanied by allodynia or hyperalgesia. There is an increased incidence of PHN in elderly patients, patients with ophthalmic herpes zoster, and immunocompromised patients. PHN may result from dorsal horn destruction, although pathophysiologic changes in more proximal central structures and distal peripheral structures have been described. Based on randomized, controlled studies, the most effective medical therapies include gabapentin, topical lidocaine, tricyclic antidepressants, and oral opioid analgesics. Surgical interventions for refractory cases including intrathecal drug administration, central ablative procedures, and central electrical stimulation continue to meet with limited success.
