The use of zygomatic implants for the retention of nasal prosthesis following rhinectomy: the Morriston experience

Abstract

Reconstruction and rehabilitation following rhinectomy remains controversial and presents a complex problem. Although reconstruction with local and microvascular flaps is a valid option, the aesthetic results may not always be satisfactory. The aesthetic results achieved with a nasal prosthesis are excellent; however patient acceptance relies on a secure method of retention. The technique used and results obtained in a large series of patients undergoing rhinectomy and receiving zygomatic implants for the retention of a nasal prosthesis are described here. A total of 56 zygomatic implants (28 patients) were placed, providing excellent retention and durability with the loss of only one implant in 15 years.

Reconstruction and rehabilitation following rhinectomy remains a complex problem. Although reconstruction with local and microvascular flaps is a valid option, the aesthetic results may not always be satisfactory. In the authors’ experience, the aesthetic results achieved with a nasal prosthesis are far superior, but patient acceptance relies on a secure method of retention and psychological acceptance of a prosthesis. The advent of osseointegrated implants has greatly improved anchorage in the nasal region ; however, the placement and success of fixtures still present challenges due to the quantity and quality of the bone available. Despite the challenges, the use of dental implants to retain a nasal prosthesis is widely documented ; however, the use of zygomatic implants in a large series is not. The technique used and results obtained with the placement of 56 zygomatic implants for the retention of a nasal prosthesis in 28 patients undergoing rhinectomy are described herein.

Methods

A retrospective analysis was performed of all patients who had undergone rhinectomy and placement of zygomatic implants (one-stage treatment) at a hospital in South Wales, UK over a period of 15 years. Inclusion criteria encompassed any patient who had a nasal malignancy requiring rhinectomy to achieve disease clearance. Exclusion criteria included patients not fit for surgery, disseminated disease, and those who opted for autologous reconstruction.

The data analysed included patient age, sex, type of rhinectomy, histology, postoperative radiotherapy, retention type, and follow-up period. In total, 28 patients underwent rhinectomy for extensive nasal malignancy with the simultaneous placement of 56 zygomatic implants.

In planning a case for rhinectomy and placement of zygomatic implants, a computed tomography (CT) scan with 0.5-mm slices and three-dimensional reconstructions are imported into two software programs, Simplant (Dentsply, USA) and Mimics (Materialise, Leuven, Belgium). This allows the implant position to be accurately planned, ensuring that the zygomatic bone is fully engaged and the infraorbital nerve/foramen is avoided ( Fig. 1 ). It is essential at this planning stage to offset the implants, with one emergence being placed 3–4 mm higher than the other, in order to allow better access when inserting the implants and to ensure easier access for the patient to clean the site. Freeform software (3D Systems, USA) is then used to design surgical guides to facilitate the offset position of the implants and guide the correct trajectory to engage the zygomatic bone. The surgical guides are fabricated in Accura ClearVue high-resolution 3D resin using stereolithography printing, or alternatively in cobalt chrome using selective laser melting. The guides are designed and manufactured in two parts to aid placement intraoperatively by increasing access. The manufacturing and delivery time is approximately 4 days and the stents are heat-sterilized prior to intraoperative use.

Fig. 1
Simplant (Dentsply, USA) software showing the planned offset position of zygomatic implants avoiding the infraorbital foramen.

Twenty-eight patients underwent rhinectomy with the placement of two zygomatic implants in one stage. The type of rhinectomy carried out in this series was classified into three types ( Fig. 2 ) : (1) standard rhinectomy, involving the nasal soft tissues only; (2) total rhinectomy, involving nasal soft tissue and the nasal bones; (3) extended rhinectomy, incorporating upper lip and or maxillary alveolus.

Fig. 2
Standard rhinectomy involves the nasal soft tissues only (yellow line). Total rhinectomy involves the nasal soft tissue and the nasal bones (red line). Extended rhinectomy incorporates any resection beyond the red line. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Wherever possible the nasal bones are maintained to provide a firm tissue base for the prosthesis and this also allows the nasal bridge to support spectacles. The inferior turbinates are removed and a minimum of 10 mm of the anterior nasal septum, which reduces crusting, improves airflow, and provides better access for cleaning.

At the study hospital, the Zygoma Brånemark System (Nobel Biocare, Göteborg, Sweden) is used. These implants have a TiUnite or machined surface, a diameter of 4.4 mm, and length ranging from 30 mm to 52.5 mm. Intraoperatively, using the surgical guide ( Fig. 3 ), a 2.9-mm rose head drill is used to create the entry point in the medial wall of the maxillary sinus. This is followed by a pilot hole of 2.9 mm drilled to full zygomatic implant length. The diameter of this drill hole is then increased to 3.5 mm using a twist drill and the zygomatic implant is then inserted. The head of the implant is angled at 45° to the patient coronal plane ( Fig. 4 ) and healing abutments are then placed to prevent overgrowth of the soft tissue during the healing phase. It is important at this stage to advance the skin over the nasal margins, as this will reduce the tissue mobility under the final nasal prosthesis ( Fig. 4 ).

Fig. 3
Left side surgical guide in place prior to placement of the zygomatic implant.

Fig. 4
Zygomatic implants in place with the head of the implant angled at 45° to the coronal plane and soft tissue sutures over the bone margins of resection.

Prosthetic construction is completed at 6 weeks postoperatively or after radiotherapy treatment is completed (during this time the patient wears a temporary nasal prosthesis). It is at this point that full implant loading can occur. CT data and patient photographs taken prior to the disease are used to construct a clay/wax prototype of the nose before moulding in dental stone ( Fig. 5 ). From the mould, a silicone elastomer nasal prosthesis is constructed with appropriate colour matching ( Fig. 6 ). The prosthesis is magnetically retained using closed field Maxi Magna abutments with the magnet residing in the prosthesis and the keeper component screwing into the threaded implant head. The patient is provided with two nasal prostheses, with the total time for final prosthetic construction being 36 h, at a cost of £2000.

Fig. 5
Clay prototype prosthesis trial.

Fig. 6
Final nasal prosthesis.

Results

Twenty-eight patients (19 male and nine female) had a total of 56 zygomatic implants placed at the time of rhinectomy ( Table 1 ). The cases were consecutive and there were no exclusions. The mean age at time of surgery was 68 years. Squamous cell carcinoma accounted for 22 cases (79%), with basal cell carcinoma, melanoma, and spindle cell carcinoma accounting for the remaining six cases (21%).

Table 1
Demographic and clinical data (patients, n = 28; implants, n = 56).
Number of patients Number of implants Number of failures
Age (years)
<59 5 10 0
60–69 9 18 0
70–79 10 20 1
>79 4 8 0
Sex
Male 19 38 1
Female 9 18 0
Histology
SCC 22 44 1
BCC 3 6 0
Melanoma 2 4 0
Spindle cell carcinoma 1 2 0
Type of rhinectomy
Standard 12 24 0
Total 11 22 0
Total extended 5 10 1
Number of stages
1 28 56 1
2 0 0 0
Postoperative radiotherapy
Yes 13 26 1
No 15 30 0
Retention type
Magnets 24 48 1
Bars and clips 4 8 0
Follow-up period (years)
1–3 11 22 0
4–6 10 20 0
7–10 5 10 0
10+ 2 4 1
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Jan 16, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on The use of zygomatic implants for the retention of nasal prosthesis following rhinectomy: the Morriston experience
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