Daniel G. Becker, MD, Stephen S. Park, MD, FACS, and Dean M. Toriumi, MD

Advances in instrument design are guided by the desire to achieve a surgical maneuver more efficaciously and accurately, such as through the use of finer rasps and smaller osteotomes. Powered instrumentation is introduced to improve precision and technical ease while minimizing tissue trauma. In this article the application of powered instrumentation for modification of the bony nasal dorsum, for lateral osteotomy, and for septoplasty is discussed.

From the Division of Rhinology and Facial Plastic and Reconstructive Surgery, Department of Otolaryngology-Head and Neck Surgery, University of Pennsylvania, Philadelphia, Pennsylvania (DGB); the Division of Facial Plastic and Reconstructive Surgery, Department of Otolaryngology-Head and Neck Surgery, University of Virginia Medical Center, Charlottesville, Virginia (SSP); and the Division of Facial Plastic and Reconstructive Surgery, Department of Otolaryngology-Head and Neck Surgery, University of Illinois at Chicago, Chicago, Illinois (DMT).

MODIFICATION OF THE BONY DORSUM

Bony profile alignment commonly is achieved with osteotomes and rasps. After conservative hump excision with an osteotome, final profile refinements often are made with a sharp tungsten-carbide rasp. Alternatively, the entire bony hump may be addressed with the rasp. The rasp is used routinely to smooth the dorsal edges of the nasal bones comprising the “open roof” after hump reduction with an osteotome. Although effec­tive, the manual rasp is a traumatic instrument that inflicts temporary damage to the nasal soft tissue, resulting in edema that may interfere with intraoperative assessments, thereby adversely affecting the surgical out­come. For example, palpable or visible irregularities may appear as late as 1 to 5 years postoperatively if small fragments or “bone splinters” are not recognized and removed. 12 Careless rasping also runs the risk of avulsing bone fragments or portions of the upper lateral cartilages.

Powered instrumentation has been designed specifically for use on the bony nasal dorsum. 12 A powered, reciprocating rasp (United Ameri­can Medical Co., McMinnville, TN and Xomed Surgical, Jacksonville, FL) with a conservative (0.5 cm) back and forth excursion is a minimally traumatic alternative for modification of the bony dorsum (Fig. 1). The pow­ered rhinoplasty drills (Linvatec Corporation, Largo, FL and Xomed Surgical, Jacksonville, FL) have an outer sheath that protects the overlying soft tissue envelope, provides suction and, with some drills, irrigation at the resection site (see Fig. 1).

Powered instrumentation has proven to be a versatile and precise method of modifying the nasal skeleton. These instruments may be used to smooth the edges of the “open roof” after osteotomy or to reduce the entire hump in a more precise fashion. The nature of these instruments also allows their use for reduction of the nasofrontal angle. 5 In the authors’ experience, the precision of the powered reciprocating rasps and powered drills is highlighted in cases where limited reduction is needed. They appear to be less traumatic to the soft tissue envelope because they do not rely on the potentially bruising back and forth motion typical of manual rasping. Because these instruments are self-powered, they are used best with a light touch for slow, incremental adjustments. The powered rasps and nasal dorsum drills may decrease the incidence of bony dorsal irregularities after rhinoplasty. 1-2

Clinical Review

Earlier reports have looked at the use of powered instrumentation for modification of the bony dorsum. 2 Using cadaver specimens, a comparison was made between nasal bones that were rasped versus nasal bones reduced with the rhinoplasty drill. Scanning electron microscopy of the cadaver specimen demonstrated a smoother surface created after use of the nasal dorsum drill (Fig. 2).

An extended clinical experience with powered instrumentation in 57 rhinoplasties from April 1996 to December 1997 is described here. A powered rhinoplasty drill (Linvatec Corporation, Largo, FL and Xomed Surgical, Jacksonville, FL) was used in 47 patients; a powered reciprocating rasp (United American Medical, McMinnville, TN) was used in 10. In cases requiring 3 to 4 mm of bony hump reduction (n = 36), the powered instrumentation was used to smooth the bony edges following dorsal reduction with a straight osteotome. In cases requiring 1 to 2 mm of bony dorsum reduction (n = 20), it was the sole instrumentation for dorsal modification. In one case requiring a 3-mm dorsal reduction, powered instrumentation was used alone.

There were 36 females and 21 males. Skin thickness varied: 16 patients had thick skin (6 females, 10 males), 33 had medium thickness skin (22 females, 11 males), and 8 had thin skin (8 females, 0 males).

The powered instrumentation was used successfully in all cases (Fig. 3). There were no complications related to the drill or the powered rasp, and no damage to the skin-soft tissue envelope. Postoperative ecchymosis and edema were improved subjectively, compared to the prior experiences of the operating surgeons. With average follow-up of 13 months (range 6 to 26 months), there were no cases of dorsal irregularities.

Discussion

Powered instrumentation appears well-suited for smoothing the edges of the “open roof” and for precise reduction of the bony dorsal hump or isolated bony irregularity. Unlike the manual rasp, powered instrumentation allows direct visualization of the operative site. The powered rasps provide a precise calibrated motion, avoiding the excessive back and forth motion of manual rasps. Current drills have a protective sheath that covers all but the active part of the drill, protecting the skin-soft tissue envelope. These drills also have suction at the resection site. No qualitative difference among the powered instruments was detected.

Powered instrumentation described in this report is not well-suited for the cartilaginous dorsum. Calibrated scalpel excision of the cartilaginous dorsum under direct visualization, when indicated, remains a reliable approach to modifying the middle nasal vault.

Bony dorsal irregularities are a well-recognized complication of rhinoplasty. In the search for an approach that could reliably assure a smoother contour without sharp edges, irregularities, or asymmetries, surgeons have reported on the use of various onlay grafts, including homograft sclera, 10 gelatin film,” temporoparietal fascia, 4 and superficial musculoaponeurotic system (SMAS). 8 The multiple proposals in the literature on this subject may suggest the lack of a completely satisfactory solution.

The incidence of postoperative bony dorsal irregularities has not been well quantified in the literature. Nevertheless, in this study, there were no cases having this complication within at least a 6-month follow-up in all patients, and with greater than 1-year follow-up in over half. The rhinoplasty drill and powered rasp may decrease the incidence of bony dorsal irregularities after rhinoplasty.

Powered Instrumentation for Lateral Osteomies

Compared to early osteotomes for rhinoplasty, significant design improvements, including smaller dimensions and subtle contouring, have allowed increasingly precise bone cuts. One of the authors (SSP) has found the powered linear osteotome (MicroAire Inc., Charlottesville, VA) to be a potentially advantageous alternative to conventional techniques. This instrument is driven by compressed air and uses a rapid vibrating action in a “to and fro” motion to allow bone cutting.

The blade of the osteotome has a 3-mm cutting surface with a guard at the distal corner. This is attached to pressurized air through a motorized hand piece (Fig. 4). The stroke distance for the cutting edge is 1 mm, reciprocating at 100 cycles/second for each pound (typical range is 50-80 psi). The osteotome is 12 cm long and can be detached from the hand piece and used independently with a mallet, if desired.

Technique

Osteotomies can be performed through either the open or endonasal approach. Wall pressure is generally set between 50 to 80 psi. Medial osteotomies are followed by intermediate (when indicated) and lateral osteotomies, although the nature of the bone cutting action permits an intermediate osteotomy to be performed after medial and lateral cuts are made. The most unique feature of the powered osteotome is its facile nature; it requires only gentle anterior pressure for prompt bone cutting action. When no pressure is applied, the osteotome will not advance. Bone cuts are in the same direction as conventional rhinoplasty, and by applying pressure on this area immediately following osteotomy, one can significantly decrease postoperative ecchymosis.

Cadaveric Study

Mason et al have evaluated the quality of osteotomies created by the powered linear osteotome. 9 In seven fresh cadaver heads, osteotomies were performed with both the powered instrument and conventional mallet techniques. The nasal skeleton and osteotomies were then evaluated. The powered linear osteotome allowed precise bone cuts along the planned path with great ease. Approximately 50% periosteal disruption was observed using either powered or conventional instruments. The powered osteotome allowed the creation of a clean intermediate osteotomy without comminution (Fig. 5), whereas intermediate osteotomies created by the mallet frequently led to small microfractures in both bone segments. This instrument allowed intermediate osteotomies to be created after medial and lateral bone cuts had been made. In addition, using an 8-mm osteotome attachment, cartilaginous and bony dorsal reduction could be accomplished in a single maneuver, beginning at the anterior septal angle, proceeding up the cartilaginous dorsum, and ending at the nasion. Although the cadaveric study demonstrated the ability to achieve cartilaginous dorsal resection with this instrument, the authors have not used this in clinical trials because it appeared more traumatic and tended to disrupt the intranasal mucosa at the junction of the septum and upper lateral cartilages. One cannot overemphasize the importance of maintaining upper lateral cartilage integrity during dorsal cartilaginous resection.

Clinical Review

From 1995 to 1998, 18 patients at the University of Virginia have had osteotomies performed with the powered linear osteotome. These patients generally had more complex deformities of the bony pyramid that necessitated irregular and intermediate osteotomies. Cartilaginous dorsal resection was performed in the traditional method with the scalpel (Fig. 6).

Discussion

Powered osteotomes offer some distinctions from traditional instruments. By virtue of the ease with which bone cuts are made, this instrumentation appears to provide greater precision in the placement and con­ tour of osteotomies. Its effectiveness is highlighted by its ability to create an intermediate osteotomy after medial and lateral cuts have been per­formed, as demonstrated in cadavers. A single operator, without relying on an assistant to use the mallet, can perform osteotomies. Disadvantages associated with the powered osteotomes include the need for compressed air and the presence of a cord attached to the end of the instrument that some may find cumbersome. With conventional osteotomies, even a sound-deadened mallet and a gentle technique may create an unpleasant noise and jolting sensation in the awake patient; this can be avoided with the powered osteotome. However, there is a different noise introduced during its use that some individuals may find equally disruptive. As with all tools, familiarity and confidence is important in their successful use. The rhinoplasty surgeon may find the powered osteotome a useful addition to his or her armamentarium.

POWERED INSTRUMENTS FOR SEPTOPLASTY

Although conventional septoplasty has changed very little over the years, there are occasions in which a more limited procedure is suited for focal pathology. For example, during endoscopic sinus surgery an isolated septal spur or fracture may limit access to the paranasal sinuses. Pediatric septoplasty is characterized by limited tissue disruption and a targeted approach. Under these circumstances, an endoscopic septoplasty may be appropriate. 3 – 7 In selected cases, the use of the powered burr is well- suited.”

The powered rhinoplasty burr, described earlier in this article, is used for the endoscopic septoplasty. An incision is made just anterior to the pathology, and a unilateral mucoperichondrial flap is elevated around the bony or cartilaginous deviation. The 0° endoscope usually is positioned first, exposing the spur, followed by the endoscopic burr (Fig. 7). Intermittent irrigation and suction is applied while the burr is in use. The burr allows direct ablation of the septal pathology whereas the outer sheath protects the mucoperichondrial flap. The only area that is removed is the pathologic septum. At times, a layer of cartilage or bone will persist in the operated area, with only the obstructing portion of the spur removed. A quilting type suture can be placed in the area of the elevated flap to reappose the septal flaps. This technique minimizes disruption of muco- perichondrial flaps and may preserve septal continuity with limited ablation.

The powered endoscopic burr has been a useful tool during the more conservative, targeted approach septoplasty.

References

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12. Tardy ME Jr: Rhinoplasty, The Art and the Science. Philadelphia, WB Saunders, 1997