Deep Lateral Wall Partial Rim-Sparing Orbital Decompression for Treatment of Thyroid-Related Orbitopathy

Overview

The described technique of DLW-PRS decompression for TRO using SONOPET(R) appears to be safe and effective, reducing the complications associated with decompressing the orbital floor and medial wall. The mechanical characteristics of this surgical too provide protection to adjacent dura mater and neurovascular structures when working in narrow spaces.

We included in this review patients who had exophthalmos at presentation (using Hertel's exophthalmometer), underwent surgery for rehabilitation of disfiguring exophthalmos and had controlled thyroid function. All patients had a minimum follow up of 6 months. Procedures that potentially might have altered the amount of retroplacement achieved by lateral wall removal, such as fat excision, rim advancement, or decompression into the paranasal sinuses, were not performed. Patients with any history of previous procedures that potentially might have altered exophthalmos measurements were also excluded for the purposes of this study. SONOPET® Ultrasonic Aspirator. The SONOPET® ultrasonic aspirator, consists of an ultrasonic handpiece that is connected to a base control module. The unit is foot-pedal controlled. The base module houses the controls to regulate the irrigation rate (between 3 and 40 mL/min), aspiration and ultrasound power parameters of the machine. The power setting is expressed as a percentage of that maximum. Aspiration reaches 500 mmHg and the aspiration setting on the machine is also expressed as a percentage of that maximum. The irrigation rate is expressed in milliliters per minute.18 Aspiration occurs through an opening at the distal aspect of the handpiece tip and the irrigation fluid (normal saline at 20°C) flows through a white irrigation sleeve surrounding the handpiece tip. The handpiece oscillates in a nonrotational fashion up to 25,000 times per second with a 0.36 mm width variation. The SONOPET®'s primary mechanism of action is torsional oscillation of a metal bone rasp at 25 kHz. This frequency is ideal for bone removal,22 as the microenvironment created only cuts mineralized tissue, while soft tissues are best cut at frequencies ≥34 kHz.23 The universal handpiece fits multiple interchangeable tips that have varying lengths, sizes, and shapes designed for specific soft tissue or bone removal purposes.22 Different sizes and angles for the cutting surface are also available. The tip used in this series is a serrated aggressive knife and the superlong payner 360°shape designed for bone fragmentation and removal24 (Figures 1 D, 2 A). Surgical technique. The procedure was performed with the patient in a supine position under general anesthesia. A single dose of IV dexamethasone (8 mg) and a 1 gr IV cefazoline were given during surgery. After corneal lubrication, the patient was prepped and draped in sterile fashion. The marked triangle incision was incised (Figure 1, A) and an initial lateral canthotomy was made in a "crow's foot" using a no. 15 Bard-Parker® surgical blade (Becton Dickinson, Hancock, NY, USA) . Dissection was performed in the preseptal plane to provide wide exposure of the rim of the lateral orbital wall(Figure 1, B). The periosteum was incised using a needle-tip monopolar electrocautery and the lateral wall was completely exposed by cutting cautery and periosteal elevators (Figure 1, C). The posterior leaf of the periosteum was mobilized and reflected, along with the temporalis muscle; this minimizes damage to the temporalis muscle during surgery and reduces future temporal hollowing.

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Interventions

Eligibility

Outcomes