Patient Assessment for Epiduroscopy

Alan David Kaye, Frank Calixto, and Mark R. Jones

25.1 Introduction

Epiduroscopy is a relatively novel interventional pain management technique indicated for the diagnosis and treatment of complex spinal pain syndromes. It provides the clinician with direct visualization of the epidural space and thus has become increasingly helpful in the evaluation of anatomic irregularities contributing to chronic lower back pain conditions, particularly in cases of “failed back syndrome,” in which postoperative perineural fibrotic adhesions and inflammation are common etiologic factors.1 A much less invasive procedure in comparison with conventional spinal surgery, epiduroscopy can be utilized as both a diagnostic and therapeutic modality; the physician operating the fiberoptic scope is simultaneously provided with direct visualization of the underlying pathologic processes within the epidural space as well as the capability of employing targeted therapeutic measures (direct lysis of adhesions, application of steroids directly onto inflamed nerve roots, etc.) not typically available by way of traditional percutaneous procedures.²

Given the appropriate clinical setting, epiduroscopy may assist in providing the patient with lower back pain with symptomatic relief when conservative therapeutic and pharmacologic measures fall short. Proper patient selection is important with epiduroscopy, as not all patients are suitable candidates. As with neuraxial anesthesia, patient refusal is an absolute contraindication. Pregnancy, increased intracranial pressure, thrombocytopenia or coagulopathy, sepsis or infection at the site of infection, cerebrovascular diseases, manifest bowel and bladder dysfunction in the S2–S4 area, congenital anomalies that do not permit safe endoscopy, inflammatory or dystrophic skin lesions in the area of the sacral canal (anal fistula, sacral osteomyelitis, etc.), meningeal cysts, meningoceles, meningomyeloceles, and known allergies to drugs required to implement epiduroscopy are also known absolute contraindications to epiduroscopy.^3,4 Relative contraindications include, but are not limited to, history of bleeding diathesis, elevated intracranial pressure, infection at the site of entry, inability to lie prone for more than 60 minutes, severe chronic obstructive pulmonary disease/cardiovascular disease, and certain neurologic diseases.

25.2 Preoperative Assessment of the Patient

Published American Society of Anesthesiologists (ASA) guidelines suggest that anyone requiring an anesthetic be given: (1) an interview accentuating medical, anesthesia, and drug history; (2) a physical examination; (3) appropriate diagnostic testing; (4) diagnostic data, including laboratories, electrocardiogram, radiographs, and consultations; (5) assignment of ASA physical status score; and (6) finally, formulation and discussion of an anesthesia plan with the patient or a responsible adult before obtaining informed consent.5,6

Therefore, prior to proceeding with epiduroscopy, a comprehensive past medical/surgical history and physical must be performed, with a focused assessment of the patient’s medical history, including pain- and nonpain-related history. This includes medications, hospitalizations, surgeries, physical examination, and prior therapeutic interventions ( Table 25.1). Past medical history can be valuable to assess high-risk patients, who will be undergoing moderate or deep sedation. The assessment should include baseline level of consciousness and/or sedation, which should also be monitored and documented during sedation. Some examples of relevant histories include previous anesthesia problems, last oral intake, snoring, sleep apnea, extreme age, height and weight, in particular related to obesity, the presence of common comorbid diseases such as diabetes, heart and lung disease, routine use of opiates and/or sedatives, and nontherapeutic drug use (e.g., tobacco, alcohol, and illicit drugs). In this regard, excessive polypharmacy is associated with increased anesthetic mortality.⁷

It is clear that information as to whether to take or hold medications can be impactful for any patient undergoing a surgical procedure. For example, all asthma, thyroid, birth control, seizure, narcotic, gastrointestinal reflux (except for TUMS), antidepressant, antianxiety, psychiatric, most antihypertensive, and statin medications should be continued on the day of surgery. Type 1 diabetics should take approximately one-third of their intermediate to long-acting (NPH and lente) medication. Type 2 diabetics should take up to one-half of combination (70/30) preparations. Insulin pump delivery should continue with the lowest nighttime basal rate and oral hypoglycemic agents should be discontinued to minimize the risk of hypoglycemia. The diuretics triamterene and hydrochlorothiazide should be continued, while potent loop diuretics should be held.⁸

25.3 Cardiovascular Medications

Work from Tarhan at the Mayo Clinic in the late 1960s documented the fact that patients who were operated on within 3 months of myocardial infarction had a 37% reinfarction rate. This rate decreased to 16% in patients at 3 t 6 months after infarction and remained at 4 to 5% when infarction had occurred more than 6 months previously.9

In recent years, additional studies related to cardiovascular medications have identified best practice strategies. For example, continued perioperative beta blockade administered according to perioperative cardiac risk reduction protocols is associated with a reduction in 30-day and 1-year mortality. On the other hand, perioperative withdrawal of beta blockers is associated with increased mortality.^10,11

A 2006 ASA Panel entitled “Highs and Lows of Blood Pressure: When Does It Really Matter?” summarized that patients with increased blood pressure, congestive heart failure, and/or coronary artery disease needed to continue angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, beta blockers, calcium channel blockers, and diuretics intraoperatively. However, patients with only high blood pressure and coronary artery disease were recommended to only continue beta blockers and calcium channel.

Statin withdrawal has also been found to be significantly associated with morbidity and mortality. In high-risk patients, significant reductions in myocardial ischemia, myocardial infarction, death, and myocardial infarction–induced death were demonstrated when statins were continued through to the surgical period.¹² High-risk patients taking both their beta blocker and statin had a dramatically significant reduction in the likelihood of having a myocardial infarction when compared with those patients who did not take either their beta blocker or statin.¹³

25.4 Dietary Supplements

Dietary supplements, which include vitamins, minerals, fiber, fatty acids, or amino acids intended to provide nutrients that may not otherwise be consumed in sufficient quantities, are sometimes defined as foods, while others classify these agents as drugs or other products. Resurgence in consumer interest in dietary supplements over the past few decades has resulted in an explosion of use of these agents worldwide, with more than 50,000 dietary supplements now available. In this regard, our own study demonstrated that one in three patients going for surgery or an interventional pain procedure was taking one or more dietary supplements, and 70% of patients did not disclose this information during routine assessment.14,15

Some of the most commonly used supplements include multivitamins, B vitamins, vitamin D, vitamin C, vitamin E, valerian, chamomile, garlic, ginkgo biloba, St. John’s wort, evening primrose oil, soy, aloe, and echinacea. The majority of patients do not disclose their use of herbal supplements to their health care providers, and this is problematic as many supplements have the potential to interact with medications used during the perioperative period or in an acute care setting. Of critical concern to anyone performing interventional pain is the knowledge that many of these herbal products can increase the risk of bleeding. This is true as well for fish oil products, which should be stopped as a best practice strategy for any interventional pain procedure.¹⁶ In this regard, the simultaneous use of multiple agents that possess anticoagulant properties (e.g., nonsteroidal anti-inflammatory drugs [NSAIDs] or aspirin along with serotonin-specific reuptake inhibitors and fish oil) will increase the risk of morbidity and/or mortality.¹⁶

Currently, there are no concise guidelines regarding the use of dietary supplements in anesthesia. However, because many of these products have significant pharmacologic effects, there is a possibility that these dietary supplements may interact with anesthesia or other medications associated with anesthesia. Discontinuation of the supplements prior to admission to a hospital or anesthesia is considered an appropriate option.¹⁷ If a dietary supplement is discontinued prior to anesthesia, the ASA recommends at least 2 weeks prior to any procedure and this is because, as supplements, they lack defined half-lives which are identified with all drugs.^18,19 For the majority of dietary supplements, abrupt discontinuation poses little to no harm. However, there are no concise recommendations when to start or to restart dietary supplements in postsurgical anesthesia. It would be prudent to stop all dietary supplements until all medications are discontinued for a duration of at least five half-lives of the discontinued medications. A duration lasting five half-lives of a drug is generally considered enough time for approximately 97% of the drug to be eliminated from the body.²⁰ Therefore, a drug–dietary supplement interaction would be less likely to occur. Given that there are tens of thousands of these products available with limited oversight from the U.S. Food and Drug Administration, incorporating supplement-specific questions into patient interviews at the preanesthetic assessment level is crucial.