Minimally Invasive (MI) Orthognathic Surgery represents a significant advancement in treating maxillofacial deformities, aiming to reduce patient discomfort and accelerate recovery compared to traditional approaches. This modern surgical philosophy focuses on optimizing surgical efficiency and safety through smaller incisions, less tissue manipulation, and specialized instruments.
What is Minimally Invasive Orthognathic Surgery?
Minimally Invasive (MI) surgery is defined as performing operative procedures in a novel way to diminish the negative consequences of standard surgical care. In the context of orthognathic surgery, this means reducing surgical operating time, intraoperative bleeding, trauma to soft tissues, and postoperative discomfort. This approach has gained prominence as scientific evidence supports its benefits.
Patients undergoing MI orthognathic surgery, which involves small incisions and minimal dissection, experience less morbidity and faster postoperative recovery. This has been observed across various procedures, including Surgically Assisted Rapid Palatal Expansion (SARPE), Le Fort I, sagittal split, and chin osteotomies.
The Core Principles of MI Orthognathic Surgery
Professor Gwen R.J. Swennen developed a new concept for MI Orthognathic Surgery, building on 25 years of experience. This concept is guided by a "MI Mindset" and consists of five key principles aimed at increasing surgical efficiency and safety while minimizing patient morbidity and improving postoperative recovery:
- Step-by-step standardization of MI Orthognathic Surgical Techniques: This increases surgical efficiency.
- Optimization of vascular blood supply and decrease of interstitial edema and swelling: This improves postoperative recovery.
- Development of dedicated MI Orthognathic Instruments and MI Orthognathic Surgical Codes: These allow for a less invasive approach and create a common language among the surgical team.
- Creation of dedicated MI Orthognathic Surgical Sequences and MI Orthognathic Sequence Template Bars: These facilitate instrumentation table organization and increase surgical efficiency.
- Dedicated storage of MI Orthognathic Instruments and Sequence Template Bars: This optimizes gathering, cleaning, and sterilization processes for a time-efficient and cost-effective clinical routine.
The "MI Mindset" Parameters for Orthognathic Surgery
The "MI Mindset" guides surgical procedures to be as minimally invasive as possible. Key parameters include:
- Use of MI surgical techniques
- Small incisions
- Less subperiosteal degloving (detachment of the periosteum)
- Care and protection of soft tissues
- Gentle retraction
- Delicate instruments
- Avoidance of unnecessary tissue trauma
- Surgical efficiency (decreasing surgical operating time)
The incision should always be "as small as possible, but big enough" to ensure adequate, safe access and prevent lacerations from excessive traction on soft tissues. Simply having a small incision does not inherently mean the procedure is less traumatic; proper instrument handling and wound care are equally vital.
Why Choose a Minimally Invasive Approach?
The rationale behind MI orthognathic surgery is deeply rooted in biological understanding and patient well-being. By making incisions shorter and performing safe degloving (moving the incision further from the mucogingival border), surgeons can:
- Reduce the risk of gingival retractions and periodontal damage.
- Maintain the non-randomized blood supply of the buccal flap.
- Limit the degloved area vertically to the osteotomy level, preserving periosteal attachment and blood supply to the alveolar process.
- Avoid acute ischemia at osteotomy and down-fracture, as well as chronic decreased intra-osseous oxygen tension, which can damage teeth and periodontium.
- Prevent dental pulp obliteration and interdental papilla loss, common in some "classical" Le Fort I approaches.
For procedures like sagittal split osteotomy (SSO), minimal yet safe degloving is crucial for maintaining blood supply to the condylar head and neck, contributing to long-term condylar volume stability. It also avoids aggressive stripping of the masseteric mandibular insertion, which can lead to unpredictable resorption and adverse aesthetic outcomes.
Key MI Orthognathic Surgical Techniques
Several studies support the safety, feasibility, and effectiveness of MI techniques in orthognathic surgery. While distinct benefits exist, factors like the steep learning curve, operating time, and costs are important considerations.
Historically, techniques for maxillary osteotomy in SARPE required no mucosal incision or mucoperiosteal reflection, using only a 2mm osteotome. More recently, limited approaches to SARPE and Le Fort I osteotomy have been described using small buccal incisions and limited dissection, often involving the "twist technique" for pterygomaxillary disjunction.
MI approaches have been developed for key orthognathic procedures:
- MI Chin Osteotomy
- MI Le Fort I Osteotomy
- MI Sagittal Split Osteotomy
- MI Maxillary Expansion
- MI Mandible Constriction/Expansion
These techniques aim to provide adequate and safe access while minimizing trauma. For example, a vertical labial incision is used for mandibular midline osteotomy to avoid extended horizontal incisions through mentalis muscles.
Advanced Tools in MI Surgery
Besides conservative incisions, specialized tools play a significant role. Endoscopes, piezoelectric instruments, and intraoperative navigation are important for MI surgery across various surgical specialties. These tools facilitate smaller incisions, reduced subperiosteal degloving, and magnified visualization.
Endoscopic approaches can be particularly useful in sagittal split osteotomies (SSO) and intraoral vertical ramus osteotomies (IVRO) to visualize the lingula and bony interferences. For Le Fort I osteotomies, endoscopy aids in safe separation of the pterygomaxillary suture through smaller incisions.
Piezosurgery (ultrasonic bone cutting) offers advantages by precisely cutting bone while minimizing damage to soft tissues, nerves, and vessels. This can lead to less pain, swelling, and faster recovery. It has been evaluated in various procedures, including multipiece maxillary osteotomies and surgically assisted rapid maxillary expansion (SARME).
Standardization and Planning for Efficiency
Standardization and systematization are crucial for improving efficiency in combined orthodontic-surgical treatment. This involves a "step-by-step" approach to diagnosis, workflow, and planning:
- 3D Cephalometry Standardization (2005): For accurate 3D landmark definition.
- Standardized Workflow for 3D Virtual Planning (2009): Published as a highly cited paper in orthognathic surgery.
- 10-Step Protocol for Clinically Focused 3D Virtual Planning (2014, optimized later): Significantly decreases overall virtual treatment planning time.
This systematic approach to planning naturally extends to surgical procedures. Individualized 3D virtual treatment planning combined with MI orthognathic surgical techniques is the key to decreasing patient morbidity and improving postoperative recovery.
Precise planning is essential for MI surgery, especially with small incisions and minimal degloving, as surgeons must know the exact osteotomy cuts and interference areas beforehand. This detailed insight into surgical movements is critical for adhering to MIS principles.
Dedicated Instruments and Surgical Codes
New and modified instruments have been developed to fulfill MI philosophy principles, optimize vascular blood supply, and decrease edema. These include:
- Sharp double-sided raspatorium (MI1): For subperiosteal tunnels and plate positioning.
- Blunt double-sided elevator (MI2): To protect soft tissues.
- Twisted blunt elevator (MI3): Specifically for retracting mental nerve and submandibular tissues in chin osteotomy.
- Dedicated double-retractor (Mx1): For paranasal soft tissue retraction in Le Fort I.
- Curved soft tissue retractors (Mx2R, Mx2L): For Le Fort I and maxillary expansion.
- Thin malleable soft-tissue retractor (Mx3): To protect nasal mucosa.
- Small channel retractors (Md1): For buccal and lingual corticotomies in SSO.
These instruments, along with others, are codified with "MI Orthognathic Surgical Codes" (e.g., Mx for Maxilla, Md for Mandible, Ch for Chin). This creates a common language among the surgical team (operating surgeon, assistants, nurse), improving communication and efficiency.
Surgical Sequences and Template Bars
"MI Orthognathic Surgical Sequences" are systematized orders of coded instruments for each procedure (e.g., MI Chin Osteotomy sequence: HK1 RT1 RT1 MI1 Ch1 MI3 OS5 BI-TAP OS6 BI3). These sequences are transferred to the surgical team using "MI Orthognathic Sequence Template Bars". These bars, labeled and numbered, facilitate the operating nurse's organization of the instrumentation table, ensuring quick and efficient access to tools and maintaining organization even if personnel change during surgery.
Dedicated storage containers for these instruments and template bars further streamline the entire process, from gathering to cleaning and sterilization, enhancing cost-effectiveness and protecting delicate instruments.
Conclusion
Minimally Invasive Orthognathic Surgery represents a significant innovation, moving beyond traditional "wide-open" approaches to offer patients safer, faster, and more comfortable treatments for maxillofacial deformities. By combining precise 3D virtual planning, standardized surgical techniques, and specially designed instruments, MI orthognathic surgery is setting new benchmarks for patient recovery and quality of life.
Frequently Asked Questions about Minimally Invasive Orthognathic Surgery
What are the main benefits of MI Orthognathic Surgery?
The main benefits include decreased patient morbidity, faster postoperative recovery, reduced intraoperative bleeding, less soft tissue trauma, and improved aesthetic results. Patients typically experience less swelling, pain, and discomfort compared to conventional surgery.
How does MI Orthognathic Surgery differ from traditional methods?
MI orthognathic surgery differs by using smaller incisions, minimal subperiosteal degloving, and specialized instruments that allow for precise bone cuts while protecting surrounding soft tissues, nerves, and blood vessels. It emphasizes careful tissue handling and relies heavily on advanced 3D planning.
What are some specific MI techniques used in orthognathic surgery?
Specific MI techniques include MI Chin Osteotomy, MI Le Fort I Osteotomy, MI Sagittal Split Osteotomy, MI Maxillary Expansion, and MI Mandible Constriction/Expansion. These often incorporate tools like endoscopes for enhanced visualization and piezosurgery for precise bone cutting.
Is MI Orthognathic Surgery suitable for all patients?
While MI techniques offer many advantages, their suitability depends on the individual patient's case, the complexity of the deformity, and the surgeon's experience. Factors like a steep learning curve for surgeons and specific case requirements mean that careful assessment is always necessary. Your surgeon will discuss if this approach is right for you.