Piezosurgery, a method of bone cutting utilizing ultrasound vibrations, widely used in oral and maxillofacial surgery, is being used in a growing number of new clinical applications. Its main advantages are preservation of soft tissues, precise bone cutting, and the possibility of use in narrow spaces. Over the past 5 years, several authors have presented their experience with the use of this tool in ENT including antromastoidectomy, stapedectomy, osteoplastic flap procedure, removal of osteomas of the frontal bone, and revision endoscopic sinus surgery.1–4
Osteomas of the paranasal sinuses are benign, slow-growing, usually asymptomatic tumors. The frontal sinus and recess are the most commonly affected sites. In most cases, surgery is not required, and radiological follow-up is performed.5 Indications for removal include frontal pain, rapid tumor growth, blockage of sinus drainage, involvement of more than half of the sinus volume, and intracranial or intraorbital complications.5,6
Endonasal endoscopic surgery of frontal sinus osteomas became possible due to the development of extended approaches to the frontal sinus.7 Draf IIb, IIb/III, and III procedures are limited mainly by individual anatomic conditions such as narrow anterior-posterior dimension of the frontal recess, not allowing the scope and burr to pass.5 The most common late complication of these procedures is scaring of the created ostium, which depends on the amount of removed mucosa created by the use of the burr.8 The use of mucosa-sparing, slim-shaped instruments allows for better visualization of the operative field, minimizes trauma, and improves late outcomes.
Removal of large osteomas with currently available equipment (irrigated curved burrs) is rather time consuming.9 Cavitation of the lesion with burrs and then fracturing and piecemeal removal of eggshell remnants is the method of choice.10 The use of saw-like cutting instruments allows for creation of narrow gaps through the tumor, decreasing resection time. Another advantage of the use of piezoelectric systems is decreased risk of cerebrospinal fluid (CSF) leak and bleeding due to preservation of the dura and vessels. For these reasons, it is a promising tool for use in endonasal surgery of bony tumors of the paranasal sinuses. The purpose of this article was to present our initial experience with the use of piezosurgery for transnasal endoscopic frontal sinus osteoma removal.
The patient was a 50-year-old, obese, asthmatic female complaining of severe frontal pain/headaches. She had previously undergone endoscopic sinus surgery for chronic rhinosinusitis with polyps 6 months prior with no improvement in headaches. Computerized tomography revealed osteoma type IV, according to Chiu and Kennedy classification, in her hypoplastic right frontal sinus, relatively thick frontal beak, and lower intersinus septum (Fig. 1). The maximum dimension of the tumor was 2.2 cm.
EQUIPMENT AND SURGICAL TECHNIQUE
The equipment utilizes piezoelectric effect. This effect results from the passage of an electric current through ceramic material, making it contract and expand. The vibrations created are amplified and transferred to the blade of the piezoelectric tool. In this way, a mechanical cutting effect exclusively on mineralized tissues is achieved. The equipment consists of a control unit, foot switch, hand piece, and exchangeable blades called tips (Fig. 2). A built-in peristaltic pump enables cooling of the tip with physiological saline.
The surgical procedure was performed under general anesthesia. In the initial phase, standard functional endoscopic sinus surgery instruments and 30° and 45° rigid scopes were used to widen the frontal recess and trim the anterior-upper parts of the middle turbinates. Draf IIb procedure was then performed with an irrigated curved burr (5.0 mm, 15° burr, Unidrive motor system, Drill-Cut X handpiece [Karl Storz, Tuttlingen, Germany]) on both sides. The posterior wall of the frontal sinus was then traced. After creating perforation of the upper nasal septum, the remnants of the frontal beak and intersinus septum were removed with the use of the burr and piezoelectric system (piezoelectric system 05.001.400 with 05.001.4001 handpiece [DePuy Synthes, West Chester, PA]) using two curved cutting tips of 10.6 cm in length: a horizontally oriented flat tip (03.000.421 S) and a vertically oriented saw tip (03.000.412 S).
The osteoma was detached from the anterior table and intersinus septum, exposed with the piezoelectric curved flat tip, mobilized with a frontal sinus curette, then reduced in size with both piezoelectric tips and removed (Fig. 3). The last phase of the procedure was performed exclusively with the use of the piezoelectric system. There were no intraoperative complications (no CSF leak, severe bleeding, orbital hematoma).
The patient was discharged home on the second postoperative day. Postoperative follow-up was uneventful.
We found the piezoelectric system effective both in widening of the median drainage pathway and during osteoma removal. A cutting, curved, flat tip was useful for detaching the tumor from the anterior table due to its slim shape (flat tip of 3 mm of width) and appropriate curvature (Fig. 2). Compared to a curved 70° diamond burr (3.5 mm in diameter), it was easier to reach narrow spaces, maneuver inside of the sinus, and did not obstruct vision.
On the other hand, the piezoelectric system caused the endoscopic image to blur due to the sprinkling of water over the cutting tip. Slight withdrawal of the scope and stopping the system regularly for several seconds made control of the operative field satisfactory. Another inconvenience was the limited choice of tips. There were only two tips of appropriate length available. Tips with less curvature would be more suitable for detaching the tumor from the posterior wall of the frontal sinus. Our impression was that the piezoelectric system removed the bone with the same speed or slightly slower than the diamond burr. This is consistent with the estimations of other authors, indicating that the time needed to complete the procedure with piezoelectric devices is longer compared to other mechanical devices.2,3
As mentioned above, soft tissue sparing is one of the advantages of piezoelectric surgery. Due to specific anatomic conditions of the presented patient and the large amount of bone that had to be removed, our opinion was that preservation of the mucosa would have been difficult with any surgical technique.
It is worth mentioning that piezosurgery devices require a different technique of handling compared to sinus burrs. Opposite of burrs, no pressure should be applied on the bone when using piezoelectric devices, as it decreases the microvibrations, and the energy is transferred to heat. This could lead to thermal injury of the nasal vestibule.
Piezoelectric surgery is a valuable tool that can improve the performance of endoscopic transnasal surgery of bony tumors of the frontal sinus.
The authors thank Peter Richards for help with language corrections, and Aleksandra Szurgocińska for help with the equipment.