Carbon Dioxide Laser Assisted Cartilage Reshaping Otoplasty Biology Essay

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Background: Most of otoplasties techniques are variations to two main concepts: sutures and sculpting. Thick cartilage and its tricky everlasting reshaping is a difficult task in suture techniques. It is more difficult to predict or control the final result in cartilage sculpting techniques. Animal studies demonstrated temperature-dependent cartilage stress relaxation during laser irradiation resulting in stable shape changes. So the aim of this study was to describe a new surgical technique of carbon dioxide laser-assisted cartilage reshaping otoplasty (CO2-LACRO) and to show its outcome.

Methods: Sixteen patients with 32 prominent ears were involved prospectively in the present study. Carbon dioxide laser evaporation of the perichondrium, together with one-third to one-half of the thickness of the auricle cartilage and a pair of parallel laser incisions on either side of the antihelix and concha were performed. The cartilages were then apposed and fixed with absorbable vicryl mattress sutures. Demographic, pre- and peri-operative details, early and late post-operative complications, recurrence rates, patients/parents and doctors satisfaction in the follow-up were studied.

Results: A total of 32 ears underwent repair. Patients ranged from 4 to 7 years (mean 5.5) with an average follow-up of 2.4 years. No cases required revision surgery. Preservation of the antihelix with good to excellent ear symmetry was obtained in all patients at follow-up. In late assessment 14 patients were pleased, 2 were satisfied and no patients were unsatisfied. All patients had at least five of the six criteria for surgical success as defined by the study without complications.

Conclusions: This technique of carbon dioxide laser-assisted cartilage reshaping otoplasty resulted in endurance of auricular appearance and symmetry, with good to satisfactory outcome to both patient/ parent and doctors.

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Introduction

Prominent ears affect approximately 5% of the population. (1) They represent the most common congenital deformity of the external ear. (1) With such a high number of over 200 different otoplasty techniques (2), no single technique has been found fitting to be approved as the standard of care for all types of auricular protrusions in different ethnic groups. Otoplasty techniques are either: cartilage-sculpting (cutting), cartilage-sparing (suturing) and composite techniques (combining sutures and sculpting). Sculpting (Cartilage-cutting) techniques include cartilaginous incisions, scoring, and abrasion of either the posterior or anterior auricular surfaces or wedge excisions. Each of the otoplasty techniques has its known tendency for certain difficulties and complications; these are inbuilt to the effects of the procedure on the auricular cartilage. Recurring problems, suture extrusion and some loss of correction over time were associated with techniques relying only on cartilage suturing procedures. (3) Tan reported a rate of 24.4% for a suture technique (4), which was significantly higher than the 9.9% of the sculpting-only technique it was compared to. Thick cartilage in certain ethnic groups e.g. non Caucasian and adults and its tricky reshaping is another difficult task in suture techniques. On the other hand, sculpting (Cartilage-cutting) techniques permanently alter the structure of the auricular cartilage (5) but it is more difficult to foretell or control the final result.(1) Sculpting techniques involving cutting procedures can irreversibly deform the shape of the ear due to unpredictable healing forces and cartilage remodeling.(6) Also, sculpting techniques come with the risk of cartilage irregularities or other sharp edges (7,8) and difficulty in revising the resulting residual deformities in secondary procedures.(3)

What is underneath the skin surface constitutes the puzzling of otoplasties surgical techniques. The inherent elastic spring of the cartilage and operation on thick cartilage e.g. non white populations and adult patients drive the surgeons searching for the ideal method to compact with the auricular cartilages.

Most of the otorhinolaryngolgist and facial plastic surgeons are accustomed using lasers in their practices. Subsequently using laser in auricular cartilage reshaping will add an innovative application. Application of laser to cartilage results in changes of its ultra structure (chondrocytes, fibrillar components of type 2 collagen and intercellular matrix material of proteoglycans & hyaluronic acid) and subsequently in change of its biophysical belongings. As studied by Sobol et al (2000) this will result in occurrence of a phase transformation (9) and acceleration of its stress relaxation (9, 10) and subsequently cartilages can be curled to the desired configuration. The precise time cartilage subunits laser energy allocation and control of thermal denaturation kinetics constitutes one of the advantages of laser over other types of surgical energy devices (10).

In German literatures Stark (11) applied carbon dioxide (CO2) laser to reduce the antihelix thickness in prominent ears. Janík et al (2008) demonstrated that the partially CO2 laser-ablated and apposed rabbit auricles healed into solid, fully viable, cartilaginous columns capable of maintaining stable shape. Also using CO2 laser allowed cartilage regeneration that was stimulated by absorbed laser energy (12).

So the aim of this study was to describe a new technique for correction of protruding ears using carbon dioxide laser-assisted cartilage reshaping otoplasty and to show its outcome.

Patient and methods:

This prospective study involved 16 patients treated by a single surgeon. The following inclusion criteria were applied: bilateral prominent ears with unfurled antihelixes, either alone or with conchal hyperplasia and without associated other ear deformities such as, lop or cup ear. The parents gave an informed consent and the study was approved by the ethical committee of the hospital.

Demographic, pre- and peri-operative details, early and late post-operative complications, recurrence rates were recorded. Photographs were taken preoperatively, at six weeks postoperatively, and at late follow-up. Early and final outcome measurements including: McDowell's basic goals of otoplasty, patient/parent satisfaction, doctors' satisfaction in the follow-up, and measurements of degree and change of protrusion and all were recorded.

The outcome was assessed objectively using McDowell's basic goals of otoplasty (13):

(i)correction of all protrusion in the upper-third of the ear, (ii) visibility of the helix of both ears beyond the antihelixes when seen from the front, (iii) a smooth and regular line throughout the helix, (iv) no decrease or distortion of the post-auricular sulcus, (v) avoidance of overcorrecting to prevent a 'glued-on' appearance of the ear and (vi) correspondence of the distance from the lateral border to the head between the two ears to within 3 mm at any given point.

Patient/parent satisfaction was recorded using visual analogue score (0-10) (0 being the worst possible and 10 being the best aesthetic outcome) in terms of overall appearance and symmetry. These were divided into three groups according to the scores: pleased (score 8-10), satisfactory (4-7) and unsatisfactory (<4).

Doctors satisfaction was assessed with the mean of two blinded physicians and scored on a visual analogue scale (0-10) (0 being the worst possible and 10 being the best aesthetic outcome) in terms of overall appearance and symmetry. These were divided into three groups according to the scores: good (score 8-10), satisfactory (4-7) and unsatisfactory (<4).

Degree of protrusion was assessed pre and post operatively by measuring the mastoid to the helical rim distance at the level of Frankfort line (a line drawn from the infraorbital rim to the superior aspect of the external auditory meatus) and at the upper border of the helix and the mean was calculated. The difference between the pre and postoperative measurements was the change of protrusion.

Surgical techniques

The operations were carried out under a general anesthesia. With the help of small, sharp cutting needles, the posterior border of the anthelix, the anterior border of the superior crus, and the fold of the concha rim are marked. The needles are pinned through the skin, and the cartilage from anterior along the marked lines. Local anesthesia (Bupivicaine with 1 in 200 000 adrenaline) was infiltrated into the medial surfaces of the auricle. Retro auricular incision was performed and the skin of the medial surface of the auricle was raised in a supraperichondrial plane.

The laser beam was delivered by means of a TEKA SL 250S (Italy) CO2 laser at a wave length of 15600 nm to the posterior surface of the auricular cartilage. The laser beam was focused to the desired spot size with the micromanbulator with a focal length of 200 mm, mounted on a surgical microscope (karl Zies, Germany) . Carbon dioxide (CO2) laser evaporation of the posterior perichondrium, together with one-third to one-half of the thickness of the auricle cartilage was beamed on the posterior surface of the auricular antihelix and the superior crus. Intermittent exposures were used (pulse repetition rate 1 Hz), the spot diameter was 2 mm, the exposure time was 0.5 seconds 5w CO2 laser beam defocused beam (spot diameter 2 mm). A pair of parallel laser incisions (reaching to two third of the thickness of the auricular cartilages leave the ventral perichondrium intact) on either side of the antihelixes and at the conchal rim (in large conchae) with a focused laser beam was performed. Intermittent exposures were used (pulse repetition rate 1 Hz), the exposure time was 0.5 seconds 8w CO2 laser beam, the spot diameter being 0.1 mm (figure ).

Pressure against the scapha allowed curling of the superior crus and the anthelix. The cartilage is fixed by absorbable 4- 0 vicryl sutures. Three mattress sutures were applied: One was above the junction of the crura, the second was just below the junction of the crura to fold the superior anthelix and the third was to fix the inferior part of the anthelix as distant as needed. The concha is mobilized down to its junction with the mastoid bone. The concha is rotated to the mastoid bone and fixed on the periostium of the mastoid bone by two or three absorbable 4-0 Vicryl sutures (Fig. 7). Skin excess was carefully resected.

Skin closure is performed with absorbable 6-0 Vicryl sutures. The dressing, which remains in place for 7 days, is packed with packing with cotton

soaked with an antibiotic-containing preparation and fixed by a head bandage.

Results

Sixteen patients met the inclusion criteria for the study (6 males; 10 females) and the total number of ears that underwent surgery was 32. All patients were operated on by the same surgeon (AR). The mean age at surgery was 5.5 years (range 4 to 7) and the mean postoperative follow-up period was 2.4 years (range 1.4 to 3.5). The immediate postoperative measurements were 20 mm or less for all ears. After early and late follow up no complications were observed.

According to the patient satisfaction with the results in terms of shape and symmetry in early assessment 13 patients were pleased, 3 were satisfied and no patient were unsatisfied. In late assessment 14 patients were pleased, 2 were satisfied and no patients were unsatisfied. Using doctor satisfaction outcome measurement in early assessment: 11 patients were good and 5 were satisfactory. In late assessment 13 patients were good, 2 were satisfactory and one was unsatisfactoy. With objective McDowell's basic goals in early and late assessment the score was (4-6) and the mean was 5 from 6.

The mean immediate postoperative change of protrusion was 14.5 mm and the mean change of protrusion found at last follow up was 14.0 mm. In last postoperative follow up the number of ears where there was an increase of protrusion were 5 (15.6%). The number of ears where there was improvement in protrusion was 11 (29 %).

Mean measurements (at the Frankfort line and at upper helical rim) of mastoid to helical rim pre-, early post- and late post- operative:

Mean (mm)

Range (mm)

Preoperative mastoid to helical rim distance

31.5

28-35

Immediate postoperative mastoid to helical rim distance

18.0

16-20

Late postoperative mastoid to helical rim distance

16.0

14-20

Discussion:

Facial laser-assisted cartilage reshaping (LACR) has gained a spectrum of clinical applications since the first report of cartilaginous reshaping by sobol (14). The effect of LASER on cartilages depends on the laser wavelength, pulse duration, irradiance and tissue thermal and optical properties. Using the currently scientific investigations concerning the optimization of parameters required for the laser-reshaping process (12,15,16) allowed the author to choose the present CO2 laser parameters.

In the present technique using the retroauricular open approach allowed precise control of the auricular reshaping process and at the same moment passed up skin laser interactions. The author accomplished LACR using ablation to a partial thickness of the medial surface of the antihelx. In animal studies such ablation was regenerated by newly formed cartilaginous tissue, originated mainly from chondrocytes present in preserved parts of the vaporized cartilage, and, to a lesser extent from perichondrial fibroblasts (11, 17). To permit better optimal angle of curling with smooth curvature of the cartilages, laser cartilage incisions were carried out with preservation of the perichondrium together with the lateral one third of the cartilage. Also this will allow strong proliferation of perichondrium with numerous fibroblasts and their transition into chondrocytes on the side opposed to the laser application (11, 17). Ayhan et al. [17] studied histomorphological changes in the rabbits auricular cartilages, modeled either with erbium: yttrium-aluminum-garnet (Er: YAG) laser or classical scalpel incisions. Laser inscions healed by formation of fibrosis-free young cartilage of permanent shape. Regeneration of the laser wound differed from that induced by classical scalpel in that the latter consisted mainly of fibrosis of the underlying connective tissue. After LACR fixation was obtained using absorbable sutures to avoid prolonged solid moulds wearing done in studies without skin inscision. This allowed stay away from permanent suture problems of extrusion and granuloma.

Although LACR without skin and cartilage incision constitutes one of the imaginings for otoplastic surgeons, multiple negative aspects can take place with such procedures. Trelles and Mordon 2007 published a report with satisfactory results after 6 months in 7 patients from 8 using a 1,540 nm Er:Glass laser. Recently Lecle`re et al (2009) performed LACR using the 1.54-lmEr: YAG laser irradiation to the auricle including the skin without anesthesia and with immediate cooling followed by 6 weeks solid silicon mold application. The draw backs were the prolonged mold use and development of contact dermatitis. Furthermore the improved in auricular shape was obtained without recurrence in 15 patients from 24 patients. The recurence rate was sever in 3/25 and moderate in 6/25 which was higher than any surgical otoplasties techniques. The outcome parameters in such studies were inadequate.

With reasnoble follow up of 2.4 years (range 1.4 to 3.5) duration no complications were observed. The improvement between early and late postoperative follow up in different obictive and subjective outcomes measuerments explain the the stabilty of healing pattern after CO2 laser application.

In conclusion the present technique of carbon dioxide laser-assisted cartilage reshaping otoplasty resulted in endurance of auricular appearance and symmetry, with good to satisfactory outcome to both patient/ parent and doctors.

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