Modified microdissection electrocautery needle.

Electrocautery is routinely used in surgical procedures. The commercially available microdissection electrocautery needles are costly. To overcome this disadvantage, we have modified monopolar electrocautery tip to function as well as commercially available systems.

INTRODUCTION

The use of electrocautery in surgery dates back to 1909 when it was used to fulgurate tumors.[1] Initially, electrodes used for medical treatments were large, specifically to avoid current concentration, with consequent burning of tissues as heat is generated when current is localized to an active electrode. Later on, it was recognized that despite an increase in current density, beneficial tissue destruction could be achieved through controlled current issuing from smaller electrodes.[2] Electrical energy tends to concentrate where the electrode radius is smallest. Delivery of highly localized heat to the tissues occurs by formation of a minute arc between the fine needle tip and the moist conducting tissue which is used for cutting action. There is a rapid increase in the tissue temperature near the electrode tip as energy is delivered, which can be controlled by adjusting power and electrode diameter. A sharper tip made of alloys with higher melting point has a reduced power requirement in electrocautery to almost 5–8 W (Watts) from 30–40 W. Hence by reducing the surface area of the cautery device, high power densities can be maintained at a relatively low voltage. The net result allows for a less dissipation of energy as heat into the surrounding tissues, which results in a smaller zone of necrosis, less damage of adjacent tissues, reduced scarring, and faster healing. Butler et al.[3] have proved that the smaller electrosurgical electrodes produced improved wound healing due to less necrosis. This concept laid the foundation for the development of microdissection needle with fine electrode tip and an efficient power usage. It has been shown that the use of microdissection electrocautery does not lead to increased rates of dehiscence or infection of wound with any significant difference in wound strength, healing, or pain when compared with steel scalpel.[456]

There are many commercial microdissection needle systems available in the market like Stryker Colorado microdissection needle which is for single use and cost around $55.00. To make this system affordable in developing and underdeveloped countries, we have modified the monopolar electrocautery tip to function as well as the microdissection needle.

Technical modification

For this modification, a standard needle of 21 gauge is separated from its hub using wire twister and taking care not to cause needle stick injury. The shaft of the needle is secured to the monopolar electrocautery tip by adapting it using an insulating tube sleeve. The insulating tubes can be customized by cutting plastic feeding tube of various lengths. The tube allows for a snug fit of the needle, which means a lesser loss of power and a secure placement of the needle with the cautery tip. The needle length and shape could be adjusted for different sites of surgery and the convenience of the operator [Figures 1 and 2]. The entire modification procedure requires not more than 2–4 minutes. The solid state generator is used for cutting pure mode, with power ranging from 5–15 W for incisions. The power was adjusted for every surgery, starting with the lowest and reaching an optimum level where there is minimum tissue drag without sparking. When using in blend mode, cauterizing effect obviates the need for local injections containing epinephrine. Using this needle, we found lower tissue drag and distortion which allows fine dissection but tactile sensitivity can be slightly hampered. The cutting was done only with the tip, and sides of the needle were not allowed to touch the site of surgery. On extensive use, we have found that this modified microdissection needle (MMDN) works best at 10–15 W on skin held under tension, lower power usually for infants and deeper tissue dissection. Intraoral surgical procedures required around 5 W. We have used MMDN for intraoral procedures like in mucogingival incision for apicoectomies, maxillary and mandibular osteotomies, genioplasty, gingivectomy, operculectomy, implant uncovering, and sialolith excision [Figure 3]. MMDN worked equally efficiently for skin and scalp incisions.

Figure 1

Monopolar electrocautery tip and needle

Figure 2

Modified microdissection needle

Figure 3

Angulation of needle to improve access

However, precaution must be taken to avoid needle stick injuries when handling a sharp needle both during preparing cautery tip and in use. During lengthy surgeries, the needle can lose its sharpness due to lower melting and may be required to change during surgery. Care should be taken not to cauterize large vessels as MMDN is not suited for this purpose. The site of incision must also be carefully marked as incisional alopecia in scalp is a recognized complication with electrocautries. Additional time in surgery may also be of some concern to surgeons; but with practice, this can be greatly reduced by gradual learning curve.

CONCLUSION

Use of this needle allows for skin-opening procedures, deeper dissection, and routine intraoral procedures. Even with this modification, we have still retained the benefits of costly patented microdissection needle. The results found by us are encouraging; and considering its cost-effectiveness, we have started using this modified instrument in almost all surgeries.