Avoiding Complications From Interventional Spine Techniques
Residency training in the field of interventional pain medicine does not currently exist. While there are fellowship programs, they differ significantly in their approaches to teaching spinal interventions. Thus, there is no universally accepted means of gaining competency in the specialty, nor is there is an agreed upon standard of knowledge that interventional pain physicians must possess. While board exams do exist, none are ACGME-accredited and there is no requirement to sit for them.
Physicians enter the field of interventional pain medicine with divergent knowledge gained from their primary specialties. However, knowledge and training in interventional techniques are acquired by varied means.1 Some learn from experienced, well-qualified practitioners during a fellowship year. Others learn by observing or taking a weekend course. Still others enter the field with little more training than having read a textbook. When performing procedures, there is usually no trained observer in the procedure suite. This means that the operator is free to do whatever he or she thinks best. Given this, and the fact that there is as yet no standardized body of knowledge required for the field, it falls to the physicians themselves to possess the knowledge and abilities necessary to provide the standard of care expected of a well-trained physician. Individual physicians must police themselves as to their competency and qualifications for safe practice. Unfortunately, it appears that often this is not the case. Over the last several years, the number of interventional procedures performed has risen dramatically, as has the number of malpractice claims.2,3 A consistent theme in these cases is that prescribed protocols have not been followed or correct techniques have not been used.4
Interventional pain specialists, recognizing these difficulties, have begun taking steps to address them. Professional societies such as ISIS and ASIPP have written guidelines and protocols that provide recommendations for proper procedure performance and avoiding possible complications. Additionally, the ISIS guidelines were recently supplemented by an excellent review of complications from spinal procedures published by Bogduk et al.4 The article reviews correct surgical technique and recommends ways to avoid complications. The aim of this article is to further supplement the literature available in the field and to provide information on how to identify and avoid common risks associated with spinal injections.
Medical History for the Spinal Interventionalist
The first and most often overlooked means of avoiding complications is a directed history. The first encounter with the patient provides important information that aids in this task. There has been much written about methods for taking the history of a patient with pain. However, only a small amount of this literature has a focus specific to interventional pain. What are the historical elements that should be taken into account when planning an interventional procedure? The information needed comes from a diverse body of literature compiled from multiple specialties including surgery, anesthesia, PM&R, neurology and radiology.
Medical Conditions and Allergies
A patient history should include identification of bleeding disorders, immune suppression, medication allergies/anaphylaxis and cardiopulmonary status, pregnancy status, neurological and musculo-skeletal status, and history of difficult airway problems.5-8 Each of these conditions can set the patient up for a very serious, if not fatal, outcome. By recognizing and properly managing problematic conditions prior to the procedure, patients can safely undergo most procedures without incident.
Patients with coronary artery disease should have sympathetic stimulation minimized.5 Procedures such as lumbar sympathetic block, celiac plexus block and others can lower blood pressure and cause a compensatory tachycardia. Patients with a history of valvular heart disease, particularly aortic stenosis, should avoid injections that cause a sympathectomy, as any reduction in afterload can cause critical aortic stenosis and death.5 Examples of such procedures include bilateral sympathetic blocks or interlaminar injections with local anesthetics. Patients with a cardiac pacemaker should have it turned off during a radiofrequency procedure or spinal cord stimulator trial to prevent interference with the transmitter signals. Patients with pulmonary disease are at risk of increased morbidity/mortality from pneumothorax during such procedures as thoracic medial branch blocks, sympathetic procedures in the thoracic spine, and even thoracic transforaminal procedures.9 These procedures should not be done bilaterally due to potential for bilateral pneumothorax and respiratory failure. Patients with uncontrolled or poorly controlled hypertension should be referred to their primary care physician prior to undergoing a procedure.5 These patients are at risk for excessive lowering of blood pressure when undergoing procedures that routinely cause a mild blood pressure decline. They are also at risk for stroke should the procedure cause excessive stimulation due to pain. Patients with liver or renal disease may incompletely metabolize sedatives, which should be administered in lowered doses. Altered hepatic function can result in clotting factor abnormalities. Coagulation studies must be done prior to a procedure.5 In addition, infectious hepatitis may present a risk to the operator and should be known prior to the procedure. Patients with pulmonary disease are at risk for hypercapnia if sedation is administered.5-8,10 Patients with rheumatologic disease on oral steroids have an increased risk of infection. Neuro-muscular disease may increase risk of fall and hip fracture. A patient with an allergy to iodinated products may be at risk of reaction to contrast dye. A history of allergy to iodinated foods such as seafood is a contra-indication for administration of contrast dye.7
Past Medical History
Family, social, and past medical history can all be important in discovering conditions that make the outcome of a interventional procedure less than favorable. Questions pertaining to the use of alcohol, tobacco and illicit drug use should be taken into consideration.5 For example, patients with a history of an ongoing addiction may be less likely to have a positive outcome from an interventional procedure as they are rewarded for the continued complaint of pain by prescription of opiate analgesics. History of lawsuit in the workers’ compensation system may lessen the likelihood of a positive outcome although this has been debated back and forth in the literature.12,13 Certainly, it has been shown that work-related litigation for chronic pain has been associated with higher levels of disability due to pain.12 Finally, patients who have a significant psychological component to their pain should have this evaluated and treated prior to undergoing an interventional pain procedure.8