Tonsillectomy new vistas
History of tonsillectomy dates back to nearly 2000 years. It was Celsius who first described the procedure in the first century A.D. The potentials for complications after this surgical procedure are still very high despite the advancements in technology. There is still no consensus between the otolaryngologists regarding the safest operating technique which is not attended by any of the classic post operative complications described after tonsillectomy.
None of the evaluated procedures has clearly shown that post operative pain could be minimized. The cause for post operative pain following tonsillectomy is due to disruption with exposure of underlying nerve endings (glossopharyngeal and vagus), and pharyngeal constrictor muscle fibres. Postoperatively exposed to external elements the exposed muscle fibres undergo spasm causing pain while swallowing. Any newer surgical technique should address this aspect of inflammation involving the pharyngeal constrictor muscles.
Subtotal intracapsular tonsillectomy:
This concept is based on minimal tissue injury. The pharyngeal constrictor muscles are not exposed. The raw nerve endings are also not exposed to the environment. The post operative pain after this procedure is very minimal and the patient undergoes a stress free convalescence period. In this procedure radio frequency probe is used. This technique is also known as “Temperature controlled radiofrequency tonsil reduction”. In this technique a RF probe is introduced into the tonsillar tissue and heated up to 40 - 70° C. A plasma field containing highly ionized particles is formed at the probe’s surface causing tissue destruction. This probe can thus be used to create small channels in the tonsil with dissipation of the energy released by ionizing radiations. This causes tissue destruction during the following days / weeks of surgery leading on to a gradual reduction in the size of tonsillar tissue. Initially there is an increase in the size of tonsil due to soft tissue oedema. Tonsil shrinkage usually occurs between the first and third weeks. The main advantage of this procedure is that since the tonsillar bed structures are minimally damaged, these patients are absolutely pain free even on the first post operative day.
Advantages of radiofrequency probe versus conventional diathermy / electrocautery:
Radiofrequency generators operate at lower frequencies than conventional electrocautery units. The cutting action of R.F. cautery occurs at 70° C. This is much lower than the cutting temperature of conventional electro cautery units which ranges between 400 – 500 º C.
The high current density which is released by the electrode causes a rapid increase in the local temperature ranging from 50 – 80 ° C. This raise in temperature causes coagulation, protein denaturation and irreversible tissue destruction. When the tissue temperature reaches the critical level of 100 º C boiling occurs at the electrode tissue interface. This boiling causes the tissue coagulum to adhere to the electrodes disrupting the current flow through the prongs.
Radiofrequency ablation uses frictional heating that is caused when the ions in the tissue attempts to follow the changing directions of alternating current.
These devises have sensors close to their tip which are capable of monitoring tissue temperatures. When the local tissue temperature reaches 100 º C the sensor automatically shuts off the current to the generator ensuring that the tissue temperature does not exceed 100 ° C.
During RF tonsillectomy the cutting mode should be paused for 10 seconds for every 10 seconds of tissue cutting.
Cold ablation tonsillectomy:
This procedure was first invented by Philip E. Eggers and Hira V. Thapliyal in 1999. This surgical procedure is performed by passing an electric current through a conductive saline media. The sodium ions in the saline are released. These sodium ions break down intracellular bonds at temperatures ranging from 45 – 60 ° C. The saline solution lowers the surrounding tissue temperature minimizing collateral excess tissue damage. Since this cold ablation technique uses bipolar probes, earthing electrodes are not necessary. Saline must be used in adequate quantities. If the amount of saline used is too low ablation fails to occur. Pressure should not be applied while using the probe tip. Application of excess pressure will cause more bleeding.
Video showing coablation tonsillectomy:
Inside out tonsillectomy:
This procedure is otherwise known as intracapsular tonsillectomy. The main advantage of this procedure is reduced post operative complications like pain bleeding etc. A micro debrider can be used to perform this procedure. The rotating debrider blade is used to shave off the tonsillar tissue from its capsule. Bleeding points if any should be cauterized using bipolar cautery. The surgeon places the rotating debrider blade in the middle of the tonsillar tissue. This is done to prevent the debrider blade from straying too close to the edge of the tonsillar tissue. A retractor can be used to shield the edges of tonsil from the rotating blade. Surgeon should take care while working close to the inferior pole and anterior and posterior edges of tonsillar tissue as these areas are highly vascular. The debrider blade should rotate at full speed, otherwise suction increases and debridement ceases.
As the debrider blade penetrates the tonsillar tissue its color changes. The middle will be white and it barely bleeds. As the blade gets closer to the edge of the tonsillar capsule a red streak starts to appear. The red streak indicates the limits of tonsillar dissection.
Harmonic scalpel tonsillectomy:
This procedure is performed using an ultrasonic harmonic scalpel. The sound frequency used is about 55.5 KHz. The major advantage of this procedure is reduced bleeding and post operative pain. However operating time is doubled when compared to the normal cold dissection and snare method.