Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT03869021 |
| Other study ID # |
392B |
| Secondary ID |
|
| Status |
Completed |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
December 30, 2015 |
| Est. completion date |
December 30, 2018 |
Study information
| Verified date |
March 2019 |
| Source |
Ain Shams University |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
Objectives: Distraction Osteogenesis is an integral part in management of mandibular defects
associated with Hemifacial Microsomia (HFM) and post-ankylotic mandibular defects. The most
difficult part in distraction osteogenesis is the prediction of distraction vector and risk
of injury to vital structures as inferior alveolar. The current study aimed to present
Three-Dimensionally Constructed Computer Guided Splints in Distraction Osteogenesis to get an
ideal vector and minimal risk of vital structures injury.
Methods: The study presents computer-guided distraction osteogenesis surgery using
prefabricated splints.
Description:
The current study was performed on a case control trial of patients complaining of hemifacial
microsomia.. The research was reviewed by the ethical committee of the authors institute
(approval number: 392, date: 30/12/2015). Written informed consent for the case to be
published (incl. images, case history and data) was obtained from the patients for
publication of this case report, including accompanying images In order to accurately analyse
the patients' condition and formulate an optimal treatment plan, a pre-operative CBCT scan
was performed using i-CAT CBCT scanner (Imaging Sciences International, Hatfield, PA, U.S.A).
Each patient was positioned in the machine and imaged at the same manner according to the
recommendations of CBCT manufacturer. The Frankfurt plane was positioned parallel to the
horizontal plane and the midsagittal plane was perpendicular to the horizontal plane.
The CBCT scan was required to fulfill the following criteria:
- Showing the full bony facial structures, extending from at least the inferior border of
the mandible to the supraorbital ridge.
- CBCT scan should be free from any motion artifacts.
- Patient biting on cotton rolls in order to free the occlusion.
- A scan of optimum quality and resolution. (0.25 mm voxel size) IV. Virtual Treatment
Planning
- The data from the CBCT scan were exported from the i-CAT Vision software in DICOM
format, which was in turn imported into Mimics Medical 19.0 software (Materialise NV,
Technologielaan 15, 3001 Leuven, Belgium) for virtual treatment planning.
- Using the "Thresholding" tool, the range of gray value sets is chosen to highlight the
mineralized structures and separate them from the rest of soft tissue structures in the
scan creating a new mask.
- Using the "Calculate 3D" tool on the new mask, a 3D rendering of the facial mineralized
structures is created and is then refined using the "Smoothing" and "Wrap" tools.
- In order to properly orient the patient's head position, analyze the deficiencies, and
standardize the planning process, the Frankfort Horizontal plane and the Midsagittal
plan were constructed. Frankfort Horizontal Plane was defined by marking the right and
left Orbitale, and the Porion of the non-affected side. The Midsagittal plane was
defined by marking the Sella, the Nasion, and the Anterior Nasal Spine.
- Using the "Multiple Slice Edit" and "Region Growing" tools when needed, the jaws are
separated and the mandible and maxilla are segmented separately.
- Using the "Distraction Wizard", an appropriate distraction type is selected. A
distractor is selected and placed on the proposed site for distraction. The osteotomy
and vector are visualized and the distractor is activated. This process is repeated
until the final outcome is satisfactory. The ideal final outcome is when the canted
occlusal plane is corrected and the mandibular midline is coincident with the facial
midline simultaneously.
- Using the "Cylinder" tool in the "Medcad" menu, virtual distractor pins and osteotomy
disk are drawn to match our selected custom-made distractor. The number of pins, their
size, and orientation differed according to the vital structures in each distraction
site. Hence, custom-made distractors were used. Guide fixation screws are also added to
provide further retention for the guide when needed. The fixation screws, osteotomy and
distractor pins are placed so as to avoid injury to any vital structures as the Inferior
Alveolar Nerve, tooth buds, and dental roots .
- Using different Boolean operation, the body of the final guide is designed to fit over
the bones and teeth and incorporate the different distractor components. It is then
exported into STL format.
- The exported STL file is printed with Formlabs Form 2 stereolithography (SLA) 3D printer
(Formlabs Inc. Somerville, MA 02143 USA) using Clear Photopolymer resin (FLGPCL02). The
finished printed model is then checked for fit with the distractor.
- Prior to surgery, the guide is submerged in a basin containing 2.4% activated
glutaraldehyde solution (Cidex) for 20 minutes for high level disinfection.
Surgical Procedure
- The patient was placed in supine position. General anesthesia was administered through
Naso-Tracheal intubation. A cannula was inserted in a peripheral vein (18G) and normal
saline infusion was started at a rate of 6 ml/kg along with Ringer's solution.
- Anesthesia was induced with IV propofol 1.5-2 mg/kg, fentanyl 1.3 μ/kg and succinyl
choline 1mg/kg to facilitate nasotracheal intubation using armored tube. Anesthesia was
maintained with isoflurane in oxygen and atracurium in a dose of 0.3-0.6 mg/kg.
- The surgical sites were prepared with povidone iodine and then draped according to the
standard oral and maxillofacial surgery operating room procedures.
- An Antibiotic dose of 1 gm Cefotaxime vial was administered followed by Dexamethasone
phosphate (as sodium salt) 4 mg vial through peripheral IV route at the beginning of the
procedure. A local anesthetic solution of Articaine 4% containing Epinephrine
(1:200,000) was infiltrated along the proposed operative field for hemostasis.
- A three-line pyramidal incision was performed. The distal incision was carried buccally
across the external oblique ridge, and then joined to a gingival incision running
buccally around the necks of the teeth on which the guide rests. The releasing incision
is carried in a curved manner inferiorly and anteriorly, keeping in mind not to extend
to the area of the mental foramen. Reflection of the flap was done with a periosteal
elevator beginning from under the periosteum of the anterior buccal incision, working
parallel to the gingival margin to detach the papillae and push distally.
- Once the field of interest was exposed, the guide was introduced onto the bone and
teeth, and moved until a tight fit was achieved throughout its fitting surface. When
needed, the guide was secured to the underlying bones by 2.0 miniscrews placed through
their preplanned guiding tubes.
- Via a small stab incision through the skin, a transbuccal trochar is introduced, through
which the self-drilling extraoral distractor pins are passed. The pins are inserted into
the mandible at their designated points of entry through the guide.
- Using a piezotome, the osteotomy line is marked and the osteotomy is initiated guided by
the osteotomy slit in the guide. The fixating screws and the guide are then removed. The
use of piezotome allowed the planning of the osteotomies through the path of the
inferior alveolar nerve without fear of nerve injury.
- After guide removal, the osteotomy is completed. The distractor is connected to the
extraoral distractor pins and is then activated to insure free mobility of the distal
segment. Once confirmed, the distractor is returned to its zero position. The flap was
then repositioned and closed using 4-0 Braided Polyglycolic Acid sutures.
