Deep Lateral Wall Partial Rim-Sparing Orbital Decompression for Treatment of Thyroid-Related Orbitopathy
Condition: Exophthalmos; Orbitopathy, Graves; Surgery
MeSH terms: Exophthalmos; Graves Ophthalmopathy
Study type: Interventional

Summary: 
      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.
    

Detailed description: 
      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.
    

Intervention name(s): Orbital decompression with ultrasonic bone removal
Intervention type(s): Procedure
Intervention description(s): Deep lateral wall partial rim-sparing decompression for thyroid-related orbitopathy using SONOPET® appears to be safe and effective, reducing the complications associated and damage to neurovascular structures.
Intervention model: Single Group Assignment
Intervention model description: Retrsopective, non-comparative case series
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Decompression; Thyroid-related; Orbitopathy