Suction modulation for the laryngeal microdebrider

Authors


  • The authors have no funding, financial relationships, or conflicts of interest to disclose.

Send correspondence to Henry T. Hoffman, MD, Department of Otolaryngology, University of Iowa, 200 Hawkins Drive, Iowa City, IA 52242. E-mail: henry-hoffman@uiowa.edu

INTRODUCTION

The design of a surgical rotary vacuum shaver as a predecessor to the microdebrider has been attributed to Urban in 1968.[1, 2] His targeted use of this device to assist in the removal of acoustic neuromas did not find general use. Powered shavers were subsequently adopted in the field of orthopedic surgery and reintroduced successfully in the 1990s into otolaryngology for use in endoscopic sinus surgery.[3] Wider application of microdebrider technology has extended its use to range from tonsillectomy[4] and adenoidectomy[5] to the treatment of gynecomastia.[6]

The first description of endoscopic resection of laryngeal papilloma with the microdebrider was published by Myer et al. in 1999.[7] These investigators predicted expanded use of microdebriders would follow anticipated improvements to include smaller blades with “less aggressive features” and angled tips. Increased use of this tool was confirmed in 2004 through a survey of members of the American Society of Pediatric Otolaryngology, indicating that the majority of responders to a questionnaire preferred the microdebrider over the CO2 laser.[8]

A more recent (2009) prospective comparative analysis following surgical treatment of children with laryngeal papilloma reported better voicing following treatment with the microdebrider than with the CO2 laser.[9] Further support for the preferential use of the microdebrider was identified from data in this study correlating worsening voice quality with increased exposure to the laser.

Expanded applications have resulted from modifications to the microdebrider to improve safety and efficacy.[10-13] Recently reported innovations include 360-degree rotation of the cutting blades, continuous tracking of the instrument using surgical navigation, and the capacity to control bleeding with bipolar energy.[14] These sophisticated modifications have focused on the microdebrider apparatus itself without addressing modulation of the suction applied to the microdebrider.

The amount of suction applied to the tissue engaged at the tip of the microdebrider is recognized as an important factor associated with surgical complications. Lunn et al. identified that inadvertent resection of normal tracheal tissue can occur when “vigorous suction is applied to the handpiece.”[1] Bhatti et al. attributed the complication of restrictive ophthalmoplegia to the strong suction of the microdebrider pulling orbital contents into contact with the microdebrider blade in the course of performing endoscopic sinus surgery.[15]

Attention to the amount of suction applied by the microdebrider has been recognized as important in surgery of the vocal folds as well. Cheng and Soliman in 2010 employed the laryngeal microdebrider to gently resect subepithelial vocal fold lesions. These investigators identified that “meticulous technique, low variable oscillatory speeds, and low wall suction are necessary to avoid injury.”[16]

To date, the only published method permitting the surgeon direct control of the intensity of the suction is a modification to the foot pedal that fixes the blade at the microdebrider tip into one of three fixed positions: closed (no suction), open (full suction), and halfway open (partial suction).[17, 18] Suction regulators have been integral to the use of suction for medical use since its inception.[19] However, we are unaware of publications reporting a method to provide the surgeon direct and instantaneous control of the amount of suction applied to the microdebrider as it is functioning.

We present a simple apparatus using common materials to modulate the degree of suction applied to tissue at the tip of the microdebrider. This system allows the surgeon to instantaneously modify the suction in graded amounts within a range from fully open to completely occluded. This technique dramatically increases the sensitivity of the microdebrider to delicately remove abnormal tissue without damaging adjacent normal tissue. It also offers the surgeon dynamic control in moving from one operative site requiring high suction to another site requiring low suction.

This report was submitted to the university institutional review board (IRB), with their preliminary analysis identifying that the publication can proceed without the need for full IRB review.

MATERIALS AND METHODS

At our institution, before implementing the described method for suction modulation, the surgeon controlled the amount of suction by verbal cues to the operating room nurse. The nurse was instructed to partially occlude the suction tubing (Cardinal Health Medi-Vac Non-conductive suction tube with Maxigrip connectors, Catalog # N720A, inner diameter 7 × 6.1 mm, Dublin, OH) by bending it (Fig. 1). Excessive pull on tissue into the microdebrider by the suction is reversed by this maneuver (Fig. 2). Significant delay can occur between modification of the suction with this technique due to communication and implementation timing, which can put delicate structures at risk.

Figure 1.

The laryngeal microdebrider has been placed through an adolescent Lindholm laryngoscope to remove papilloma, with the nurse compressing the clear plastic suction tubing to modulate the suction drawing tissue in to the microdebrider from the vocal cord.

Figure 2.

Excessive suction may draw an undesirable amount of tissue into the microdebrider tip. This amount of suction may be desirable for removal of large lesions but could damage the true vocal fold if applied to a small lesion by injuring the underlying vocal ligament or adjacent normal vocal fold epithelium.

The laryngeal microdebrider (Xomed XPS Shaver system 2.9 with a Magnum handpiece; Medtronic-Xomed, Jacksonville, FL) offers the finesse to carefully remove tissue with variable speeds of blade rotation. We have identified that a single rotation of the microdebrider blade when low suction is controlled by the surgeon may draw small irregularities into contact with the slow-moving blade. This controlled removal is similar to a single closure of curved scissors (Fig. 3) in carefully separating vocal fold irregularities from the adjacent normal tissue. Very small irregularities on the vocal fold are difficult to grasp with forceps. The microdebrider can be used to bring small amounts of tissue into contact with the slowly rotating blade with dynamic control of the suction. This technique permits a more refined removal than unsuccessful efforts to grasp small lesions with forceps (Fig. 4).

Figure 3.

An alternative to use of the microdebrider for small superficial lesions of the vocal folds is identified through use of curved scissors alone. Difficulty in grasping the tissue for removal compromises this technique when compared to use of the microdebrider with low suction.

Figure 4.

Use of the microdebrider with fine-tuned modulation of suction permits a similar removal with a small amount of suction and a single rotation of a slow-moving blade. A smaller amount of suction, dynamically modulated, permits selective removal of the papilloma, sparing the adjacent normal tissue.

The instantaneous control of small changes in suction pressure that is desirable to address lesions of the vocal cord is not available to the surgeon through current technology. For that reason, we developed a system providing the surgeon with direct control of the suction.

A 3/8-inch rubber tubing is connected to the suction port of the microdebrider and looped into a figure eight over the handpiece. This assembly is secured with tape to permit the surgeon to compress the tubing with his thumb or finger. This compression functions as a pinch valve to modulate the degree of suction with digital pressure (Fig. 5).

Figure 5.

Digital occlusion of the compressible brown rubber tubing with either the thumb or finger provides the surgeon with dynamic control of the amount of suction delivered to the tip of the microdebrider.

This rubber tubing is commonly employed at our institution during otologic surgery owing to its flexibility. It is easily compressed and has memory to restore its uncompressed configuration. It has a 3/8-inch outer diameter and 3/16-inch inner diameter and is purchased in 48-inch-long segments (Hygenic Extruded Natural Rubber Tubing; Hygenic Corporation, Akron, OH). This rubber tubing is connected to standard plastic tubing with a connector designed to connect any combination of tubing ranging from 5 to 11 mm (3/16 to 7/16 inch) (5-in-1 Tubing Connector; Busse Hospital Disposables, Hauppauge, NY).

Digital pressure applied by the surgeon to the tubing compresses it against the underlying handle of the microdebrider. The tubing has optimal properties that permit easy deformability to permit refined adjustment in the amount of suction passing through it with compression. The compressible tubing readily immediately re-expands to its normal opening to restore suction as the pressure is removed.

DISCUSSION

Mortensen and Woo reported their management of a complication ascribed to improper use of powered instrumentation in management of a vocal fold polyp with web and granuloma formation.[20] The authors concluded that “powered instrumentation should be used with care in the larynx.” The adaptation we have developed to permit modulation of suction increases the sensitivity of the microdebrider so that it can used in a much more delicate fashion.

The value of immediate surgeon-directed control of the amount of suction has been made apparent by the past 52 microdirect laryngoscopies for recurrent respiratory papillomatosis (RRP) done by the senior surgeon over the past 14 months. The first 45 procedures were done with nursing control of the suction, as described, and were associated with inconsistency in refining the amount of suction. The initial seven cases in which the new technique was used were the first seven cases following introduction of the method. There was no other specific selection in choosing these cases. These seven cases were identical (laryngeal RRP) to those in which the previous technique of nurse-controlled suction modulation was used. There were no issues or complications with the new approach.

Problems in maneuvering long-handled instruments through a narrow bore laryngoscope for delicate vocal cord surgery have been acknowledged.[21] The additional coordination required of the surgeon to digitally modulate the suction in the course of positioning the microdebrider in the larynx can increase the complexity of these delicate maneuvers. As a result, we have begun to develop a foot-pedal control (patent pending) that will further refine the control of endoscopic laryngeal resections.

CONCLUSION

The laryngeal microdebrider is a valuable tool in the management of papillomas and other lesions of the upper aerodigestive tract. Advances in microdebrider technology to date have not adequately addressed the need to provide the surgeon with a finessed control of the amount of suction. Inability to control the amount of suction can contribute to major complications and morbidity in laryngeal surgery. We have addressed this problem with a simple yet effective solution for surgeon-modulated dynamic suction control. Expansion of this technique to other microdebrider uses is anticipated with the use of the foot pedal flow modulator, which we have under development.

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