Locking stylet

Traction devices specialized locking stylets, snares, sutures, grasping, or other devices used to engage or entrap and remove the lead or lead fragments. 

In fact, by stiffening the lead, stylet wires minimize the chance of lead breakage during traction and assist sheath advancement, which results in the extraction of a greater amount of intact lead. In other words, stylet wires, as do locking stylets, improve tensile strength of the leads and thus minimize the chance of lead breakage however, they do not eliminate the other complications associated with traction. 

Locking stylets lock inside the inner lumen of the lead with different locking mechanisms, and recently introduced devices can be unlocked and repositioned if necessary. Even though different kinds of locking stylets have been used in the past, there are only a few types now in use ... 

Wilkoff locking stylet (Cook Vascular Inc., Leechburg, PA, USA) (Fig. 4.3) this stylet has a small flange at the tip that is locked into the conductor coil when a thin, preloaded cylinder... 

Fig 4.3 Wilkoff Locking Stylet after the stylet is advanced to the tip of the lead, unlatch the tubular handle of the locking mechanism by removing the pin (a) and lock the stylet in the lead by firmly advancing the tubular handle forward while holding the loop handle in place (b)... 

There are some limitations to the use of a locking stylet. Once it is inserted into the lead, it may sometimes be difficult or impossible to reverse the locking mechanism and remove the device. Furthermore, if the inner conductor is broken or distorted, it is impossible to introduce or pass the stylet. Excessive force can dislocate the stylet, or the distal conductor coil can still unwind or even disconnect from the electrode. 

Kennergren C et al (2000) Cardiac lead extraction with a novel locking stylet. J Interv Card Electrophysiol 4(4) 591-593... 

Byrd CL et al (1990) Intravascular lead extraction using locking stylets and sheaths. Pacing Clin Electrophysiol 13(12 Pt2) 1871-1875... 

From December 1988 to April 1994, the extraction of 2,195 intravascular pacing leads from 1,299 patients was attempted at 193 centers. Leads had been implanted for 0.2 months to 24 years (mean 56 months). Indications were infection (54%, including 10% septicemia), removal of nonfunctional or incompatible leads (40%), and other causes (6%). Extraction was attempted via the implant vein using locking stylets and dilator sheaths via the femoral vein using snares, retrieval baskets, and sheaths or using both approaches. With this technique, 86.8% of leads were completely removed, 7.5% were partially removed, and 5.7% were not removed [16]. 

From January 1994 through April 1996, extraction of 3,540 leads from 2,338 patients (mean age 64 years, range 5-96) was attempted at 226 centers. Indications for removal were infection (27%), nonfunctional or incompatible leads (25%), Accufix or Encore leads (46%), or other causes (2%). The leads were implanted for a mean of 47 41 months (maximum 26 years) 53% were atrial leads, 46% ventricular leads, and 1% superior vena cava (SVC) defibrillating coils. The conventional technique for mechanical dilatation with Cook extraction-kit tools (Cook Vascular Inc., Leechburg, PA, USA) was used. Extraction was attempted via the implant vein using locking stylets and dilator sheaths and/or transfemorally... 

After these reports, many other single-center experiences were published, but no significant contribution about technique or results was added but in a few cases. In 2003, Mathur et al. [18] published their clinical experience about the removal of 165 leads in 80 patients using traction and/or locking stylets and dilator sheaths (89.7%), Byrd workstation (6.1%), and open thoracotomy (4.8%). Complete removal was achieved for 143 leads... 

The use of a locking stylet during transvenous removal can be due to the decision to use a traction device (as the main extraction tool or in combination with sheaths). Obviously, if the stylet cannot be inserted or if it stops very early in the coil lumen, traction cannot be performed. Regardless of the use of traction devices, the presence of a stylet into the lead is helpful during any dilatation technique. Either mechanical or powered sheaths, while advancing over the lead and freeing it from binding sites, induce mechanical stress on the lead body. The stiffer the lead, the more effective and safe is dilatation. 

Fig. 6.3 The locking stylet. This is a 60 cm, relatively stiff stylet, with a wire-loop handle and a fine wire wound clockwise at the distal tip. The stylet is advanced to the tip of the lead, where the stylet is locked in place with counterclockwise rotation. (Photograph courtesy of Cook Pacemaker Corp., Beachberg, PA.)...

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