Surgery for Vasospastic Disorders
Upper extremity symptoms and signs of vasospastic disorders may be primary (example: Raynaud disease or phenomenon) or secondary (example: occlusive disease or nonvascular disorders). Pain on exposure to cold is often associated with classic triphasic color changes in the digits as described initially by Raynaud. Raynaud disease is an idiopathic process in which these color changes occur. It is rarely progressive, is associated infrequently with occlusive events, rarely results in amputations or ulcers, and is often self-limited. In contradistinction, Raynaud′s phenomenon generally is related to collagen vascular diseases and severe occlusive events.1
Vasospasm is seen after occlusive disease (thrombosis and embolism) and may be a debilitating symptom. Pain on exposure to cold without classic color changes frequently occurs after nerve injury, vascular injury, or skeletal trauma. Ulcers, nonhealing sores, bacterial infections, refractory fungal nail infections, and gangrene of digits may occur with severe vasospasm and associated vasoocclusive disease in the presence of inadequate collateral circulation. Primary and secondary vasospastic disorders produce ulcers or gangrene in association with occlusive events in the presence of adequate collateral circulation. Within the Wake Forest classification, patients classified in groups II and III may require surgical intervention for refractory symptoms ( Table 45.1 ). Patients in groups IIA or IIIA benefit significantly from peripheral arterial sympathectomy (PAS). For group IIB and IIIB patients with “inadequate collateral circulation,” the response to PAS is variable. It depends upon the extent of the “vasospasm” creating inappropriate arteriovenous shunting and the degree of nutritional deprivation versus the inadequacy of the arterial inflow capacity or total flow.
The mainstay of management for symptomatic vasospastic disease is medical and consists of environmental modification, biofeedback, and oral medications (predominantly calcium channel blockers). The role of botulinum toxin—while enthusiastically advocated by some practitioners and supported by preclinical studies—has not been defined. There is no level I evidence to support the efficacy of toxin injections, and it is not labeled for this use by the FDA.
Proximal surgical sympathectomy produces transient improvement with rebound problems; therefore, it is not recommended for patients with vasospastic disorders. The terms peripheral or periarterial sympathectomy (PAS) are synonymous and describe the surgical/microsurgical mechanical interruption of sympathetic nerves to and within the adventitia of small- and medium-size arteries.2–5
Refractory symptoms of pain on exposure to cold in spite of environmental modifications and calcium channel blockers
Nonhealing ulcers or gangrene
Collagen vascular disease and vasospastic involvement, in which case PAS may be performed in isolation or in conjunction with arterial reconstruction and digital amputations
Patients with calcific arteritis, including those patients undergoing renal dialysis
Prophylactic PAS surgery for collagen vascular patients with associated Raynaud phenomenon
Blood is tested to screen for coagulopathies.
A preoperative Allen test with Doppler ultrasound is administered to assess vascular patency.
The digital brachial index (DBI) is evaluated. The (DBI) represents the ratio of the systolic arterial pressure of the digit to the systolic brachial pressure. An abnormally large pressure gradient between the two segments defines obstructive (structural) disease (stenosis, thrombosis, embolus) in the intervening segment. Each individual segmental arterial systolic pressure can be obtained by using the placement of pressure cuffs and a measure of distal flow ( Fig. 45.1a ). DBIs greater than 0.7 indicate adequate circulation, whereas values of 0.7 or less suggest inadequate arterial flow to the digit and support intervention.
Laser Doppler fluxmetry uses laser light to measure the flux (velocity × number of blood cells) using the Doppler effect. It provides real-time, noninvasive measurement of cutaneous perfusion by using a laser-emitting probe.
The laser Doppler perfusion imaging technique is a quantitative measure of surface skin blood flow. Blood flow is evaluated noninvasively by using a series of laser measurements at multiple sites. A surface area of 12 × 12 cm of the hand is scanned in ~ 4.5 minutes to demonstrate a “snapshot” of the spatial distribution of cutaneous microvascular perfusion. The data are measured with the patient in a thermoneutral environment in the absence of stress.
Angiography is essential for preoperative planning.
Computed tomography angiography (CTA) is a recently implemented modality giving high-resolution vascular images with details of the adjacent bone and soft tissues. Compared with standard digital subtraction angiography, it can add or subtract tissues, hardware implants, and vessels to provide an unsurpassed detail.
Isolated cold stress testing (ICST) provides helpful vasomotor information. ICST provides a mild cold challenge (4°C exposure) to the hands with 20 minutes of cooling followed by 20 minutes of rewarming at room temperature. Digital temperatures and microvascular perfusion (laser Doppler fluxmetry) are monitored throughout the test.6