Brain Circulation

: 2019  |  Volume : 5  |  Issue : 1  |  Page : 36--40

Snuff box radial access: A technical note on distal radial access for neuroendovascular procedures

Gary Rajah1, Richard Justin Garling1, Miles Hudson1, Ali Luqman2,  
1 Department of Neurosurgery, Detroit Medical Center; Wayne State University, School of Medicine, Detroit, MI, USA
2 Department of Neurosurgery, Detroit Medical Center, Detroit, MI, USA

Correspondence Address:
Dr. Gary Rajah
Department of Neurosurgery, Detroit Medical Center, Detroit, MI 48201

How to cite this article:
Rajah G, Garling RJ, Hudson M, Luqman A. Snuff box radial access: A technical note on distal radial access for neuroendovascular procedures.Brain Circ 2019;5:36-40

How to cite this URL:
Rajah G, Garling RJ, Hudson M, Luqman A. Snuff box radial access: A technical note on distal radial access for neuroendovascular procedures. Brain Circ [serial online] 2019 [cited 2022 May 24 ];5:36-40
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Radial access has been used in the field of interventional cardiology for years and is associated with very low access site complication rates, decreased length of stays, and decreased hospital charges.[1] Transradial access was originally described in 1989 and has since been incorporated into a myriad of interventions.[2] Recently, radial access has become more prevalent in neuroendovascular procedures due to more pliable catheters and technological advances allowing for smaller diameter radial access to distal intracranial vasculature. Unlike interventional cardiology procedures, the arch and cervical vessels must be interrogated during neuroendovascular procedures which require longer, more trackable catheters.[3],[4] Traditional radial artery access can typically accommodate up to 6-French sheaths, and the arm is placed on an arm board in a supinated position. Micropuncture is then completed on the ventral radial artery just proximal to the hand. Benefits of radial access include patient satisfaction, immediate ambulation, and lower access site complication rates. One cost–benefit analysis noted 275 dollars savings per patient accessed radially instead of femorally.[5] From a surgeon's perspective, traditional radial access with the patient's hand and arm supinated on a lateral arm board can ergonomically feel different than transfemoral access and can require an operator to stand closer to the radiation source. Conventionally, radial access in neuroendovascular procedures was used primarily for posterior circulation access, rescue, or bailout access when transfemoral access could not be obtained.[6]

 Snuff Box (Aka Distal Lateral Radial) Access

The anatomic snuffbox is a triangular-shaped depression on the radial side of the wrist. The “snuff box” was named for its unique ability to cradle powdered tobacco for insufflation. Its boundaries include laterally the extensor pollicis brevis and abductor pollicis longus tendons. The medial border is the tendon of extensor pollicis longus. Proximally, the styloid process of the radius is the landmark, while the floor consists of the scaphoid bone. The distal radial artery lies at the depth of the snuff box passing along the scaphoid from its ventral location to its dorsal palmar arch. The distal radial artery is roughly 80% of the size of the vessel in the forearm and roughly 2.5 mm.[7] The deep palmar arch is the branch of the radial artery in the snuff box emanating from the superficial arch at the proximal wrist. With distal radial access, iatrogenic occlusion seems to be better tolerated and the vessel can be accessed more proximally at a later date given the preserved traditional access point at the ventral wrist. An occlusion at this distal location theoretically preserves the superficial palmar arch and its collaterals. The superficial branch of the radial nerve runs just proximal to the artery but more superficial. Distal transradial lateral access or snuff box access has been previously detailed in cardiology literature. The left radial snuff box access allows for comfortable positioning of the patient's hand by the right groin, which permits the operator to stand at a further distance from the radiation source, allowing for patient comfort and an ergonomically friendly workflow similar to femoral access [Figure 1]. One study of 70 cardiac patients noted a snuff box arteriotomy failure rate of eight patients.[8] Further benefits cited for snuff box access include shorter discharge times due to statistically significant decreases in the time needed for radial artery compression (69 min less than traditional radial puncture for punctures in the snuff box in patients undergoing cardiac interventions).[9] As of 2018, only 200 snuff box radial access cases had been described and predominately in the cardiac literature.[9]{Figure 1}

 Snuff Box Radial Access for Neuroendovascular Procedures

There are very few descriptions of this relatively new access point in the neuroendovascular literature aside from a case report published in 2019 which details the use of snuff box radial access for one diagnostic angiogram and one mechanical thrombectomy.[10]

We have recently switched to a predominately radial approach to neuroendovascular surgery. The snuff box radial approach has been used for all of our diagnostic cases and many of our interventions since the switch from femoral access. To date, we have completed 24 diagnostic and interventional cases through the anatomic snuff box. There have been no access site complications, and hemostasis is obtained with a TR Band radial compression device (Terumo) placed with the balloon on the snuff box. Gauze can be fashioned for extra compression should the balloon not sit on the snuff box correctly (the TR band was designed for traditional radial access). Our typical diagnostic angiogram is completed with a 4- or 5-French short sheath with a radial cocktail consisting of heparin, nitroglycerine, and verapamil. This cocktail is given after the transitional dilator is placed. Next, a 4- or 5-French Simmons 2 Glide catheter (Terumo) is used for diagnostic angiography. We have aborted snuff box access and converted to femoral or traditional radial access in three cases, two of which were related to difficulty with placing intracranial guides due to patient anatomy and one failed access attempt. At this time, emergent thrombectomies are assessed for ease of access and the easiest and fastest access completed. However, we are performing carotid stents radially with the technique in selected patients.

This approach offers the operator a very similar experience to transfemoral access as the hand is left in the anatomical position (thumbs up) at the side (next to the groin). The sheath exits the wrist at a 30° angle and is very supportive given the surrounding tendons and the scaphoid bone. No closure devices are needed, and when a 4-French sheath is used, coagulation studies need not be as stringent as with traditional transfemoral access. Nursing staff monitors our patient for 1 or 2 h depending on sheath size and coagulation profile. Further, the patient can ambulate and sit up immediately once the procedure is completed and patient satisfaction has been encouraging. Patients appreciate not having to expose or have their groin shaved for traditional femoral access. Companies such as Merit Medical is now making a new snuff box-specific compression band that is customizable (PreludeSYNC Band) catering to this distal approach.

 Our Snuff Box Access Technique

The patient is placed onto the table in the supine position with their arm at their side and thumb pointing up. The anatomic snuff box is palpated and the radial pulse identified. Allen's test or similar test is utilized to document palmar collaterals. After infiltration with lidocaine, a linear skin nick or incision (depending on the sheath or guide size) is utilized to open the skin. A micropuncture needle is directed under ultrasound into the distal radial artery keeping in mind that the vessel is traveling up and lateral toward the operator (for the right-sided access, the needle must angle inferior and medial). Once a flash of blood is obtained, a 0.018 inch Cope Mandril is used to cannulate the artery. A transitional dilator is utilized at this point and the radial artery cocktail given. Next, a 0.038 inch Bentson wire (Cook Medical) is utilized and the 4–6-French short sheath is placed [Figure 2]. For focal radial artery spasm at the apex of a short sheath, one bailout maneuver we have performed is the placement of a 25-cm sheath to bypass the spasm after verapamil injection if the wire is able to freely traverse the narrowing. Our preferred 6-French guides in 070 lumens include Benchmark (Penumbra) for posterior circulation procedures or Envoy (Depuy-Synthes) for anterior circulation when added firmness is needed. For procedures demanding large bore guide catheters 0.088–0.091 inch, we utilize the Infinity or Infinity Plus guide (Stryker) with a sheathless technique. Berenstein diagnostic catheters are utilized for coaxial placement of guide catheters into the ipsilateral vertebral artery to radial puncture. Simmons 2 Diagnostic (Glide catheters for diagnostic procedures) catheters are used for anterior circulation access into the carotid arteries or contralateral vertebral artery access. We have successfully reaccessed snuff box access points as soon as 5 days after the first puncture with ultrasound.{Figure 2}

 Snuff Box Radial Neuroendovascular Case Examples

[Figure 3], [Figure 4], [Figure 5], [Figure 6]

In the first case we performed a snuff box radial approach with a 5-French short sheath (Terumo) [Figure 3]. A 5-French Simmon 2 glide catheter and 0.035 glide wire (Terumo) were utilized to access and climb into the right external carotid artery. The patient had a life-threatening oral cavity hemorrhage from a recent tumor biopsy. A small pseudoaneurysm within a tumor blush was seen and embolized with Onyx 34 through Headway Duo microcatheter (Microvention) was coaxially placed through the Simmons 2 Glide catheter for embolization. Tip: Radial-placed sheaths even the Glide Simmons 2 catheters are supportive enough to perform embolizations in extracranial vessels.{Figure 3}{Figure 4}{Figure 5}{Figure 6}

In the second case we performed a snuff box radial approach with a 6-French short sheath (Terumo) [Figure 4]. A Benchmark guide catheter (Penumbra) over a Berenstein catheter was used to access the V4 vertebral artery. A Headway Duo microcatheter (Microvention) was used for parent vessel superior cerebellar artery (SCA) takedown given a rapidly enlarging ruptured 9-mm flow-related SCA aneurysm due to a dural arteriovenous fistulae/arteriovenous malformation at the precentral vein. Coils and Onyx 34 were utilized. Tip: Radial access for posterior circulation procedures provides a simple route when ipsilateral to the vertebral artery; this access is preferred, especially in the elderly as mobility is not limited.

In the third case we utilized a snuff box radial approach with a 6-French 25-cm sheath given some mid radial artery spasm that only a Bentson wire (Cook Medical) would initially cross [Figure 5]. The 25-cm sheath was able to reach the brachial artery. On removal of the sheath, the radial artery was patent. A Benchmark guide catheter (Penumbra) was again utilized and this large 12-mm SCA/basilar artery aneurysm was stent coiled with a low-profile visualized intraluminal support stent (Microvention) in the basilar/left posterior cerebral artery and numerous HydroCoils (Microvention). Tip: Sometimes, focal spasm at the end of a short sheath can impede access in the radial artery, after giving verapamil, if wire will freely pass, a 25-cm sheath can be placed radially to bypass this.

We utilized an Infinity Plus 091 80-cm guide (Stryker) without a short sheath through the snuff box [Figure 6]. A Simmons 2 130-cm (Cook Medical) diagnostic catheter was placed coaxially through the guide to access the right common carotid artery. A Spider FX (Medtronic) 4-mm distal protection device was utilized and a Xact stent (Abbott) placed across the tandem common and internal carotid stenosis in this symptomatic patient. Balloon angioplasty with a 5-mm Euphora balloon (Medtronic) was completed. The tight turn from the subclavian into the right common carotid artery was difficult to manage; however, with slow steady pressure on the stent, the Infinity Plus guide remained stable and allowed for the stents passage into the carotid artery. Tip: Large-bore catheters can be placed through the snuff box technique; we recommend no short sheath be utilized.


Snuff box, or distal transradial access, is a useful technique in a surgeon's armamentarium. While this technique's use is in its infancy within the neuroendovacular setting, at this time, it appears to be safe, well tolerated, and preferred by patients over transfemoral access.


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