The Spinal Wada Test: Adapting a Neurointerventional Technique for Bronchial Artery Embolization
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LETTER TO THE EDITOR
EMBOLISATION (ARTERIAL)
The Spinal Wada Test: Adapting a Neurointerventional Technique for Bronchial Artery Embolization Jordan D. Perchik1
•
Joel E. Perchik2
Received: 12 May 2020 / Accepted: 19 July 2020 Springer Science+Business Media, LLC, part of Springer Nature and the Cardiovascular and Interventional Radiological Society of Europe (CIRSE) 2020
The spinal Wada test, first described by Doppman et al. in 1986, is an adaptation of the protocol of a Wada-Rasmussen test. Various doses of phenobarbital (2.5–10 mg) and lidocaine (2.5–20 mg) were injected directly into the artery of Adamkiewicz of adult rhesus monkeys resulting in a transient lower extremity paraplegia with a dose-dependent duration of symptoms ranging from 3 to 30 min [1]. The authors suggested that the spinal Wada could provide a reproducible and reversible means of evaluating risk of spinal cord infarction prior to embolic procedures. Since being described in 1986, there has been infrequent mention of the technique in the interventional radiology literature and no further large-scale studies have been performed to evaluate optimal medication dosing, patient selection, or risks of the procedure. Although it has largely faded from the Interventional Radiology, the spinal Wada test has been adapted in neurointerventional and neurosurgical procedures, and is more commonly referred to as ‘‘provocative testing.’’ Provocative testing, in cases such as embolization of spinal arteriovenous malformation, dural arteriovenous fistulas, or spinal neoplasm, is used to evaluate for anterior spinal artery anastomosis and determine the risk of spinal & Jordan D. Perchik [email protected] Joel E. Perchik [email protected] 1
University of Alabama Birmingham Department of Radiology, 619 19th Street South, JT N338, Birmingham, AL 35249, USA
2
Baptist Memorial Hospital Department of Interventional Radiology, 6019 Walnut Grove Road, Memphis, TN 38120, USA
cord infarction. After appropriate positioning of the microcatheter, 50 mg of sodium amytal is injected intraarterially followed by 20–40 mg of preservative free 2% lidocaine [2]. If there is anastomosis to the anterior spinal artery, the patient should experience transient lower extremity weakness or paralysis or a decrease in amplitude of somatosensory evoked potentials (SSEP) or motor evoked potentials (MEP). Alternatively, amobarbital (50 mg) or propofol (7 mg) with 2% lidocaine has also been shown to effectively provoke transient focal neurological effects [3]. In the treatment of spinal AVMs, provocative testing has demonstrated a high negative predictive value (97.6%); if provocative testing does not induce a neurological deficit, there is a low risk of radiculomedullary artery anastomosis and spinal cord infarction [2]. Bronchial artery embolization (BAE) is the most successful treatment for massive hemoptysis, achieving control of hemorrhage in 77–90% of cases. Although the procedure is generally well tolerated, devastating neurologic complications can occur, including sp
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