If you’re a fan of Star Wars, you might have noticed something about Senator Orn Free Taa in the episode “Devil’s Deal.” He’s a corpulent Rutian Twi’lek who treats politics like sport and indulges in his lavish impulses.
Orn’s pointed humanoid ears are smaller than those of other male Twi’leks from the prequel trilogy and other Star Wars media. This is a significant difference.
Microvascular Reconstruction of Advanced ORN
Patients presenting with advanced ORN, often after less invasive therapies have failed, need aggressive debridement and microvascular reconstruction. This allows restoration of bony continuity and provides a soft tissue foundation for dental rehabilitation. In addition, it introduces tissue with a nonirradiated blood supply into the area, increasing the chance of wound healing and bone viability.
However, surgical complications are common in this challenging patient population. Despite advances in surgical technique, the risk of flap loss is still a significant concern and may result in suboptimal oral rehabilitation and adverse long-term outcomes. Several factors that increase the risk of free flap failure include previous neck dissection, infection and radiation-induced wound healing defects.
Despite the challenges, ORN can be managed with aggressive debridement and microvascular reconstruction. Using this approach, patients can have successful resolution of their ORN with the preservation of their facial morphology and function, masticatory ability and oral hygiene. Furthermore, reconstruction can also restore the aesthetic appearance of the head and neck.
This is an important step in preventing the progression of ORN to the more severe stages, such as pathologic fracture and orocutaneous fistula. This has been shown to be possible with a combination of improved oral hygiene, transoral and intraoral debridement, and the use of hyperbaric oxygen (HBO) therapy, which has been demonstrated to improve wound healing by increasing oxygen tension and promoting vascular proliferation.
The objective of this study is to review the clinical outcomes of ORN patients undergoing a combination of aggressive debridement and microvascular reconstruction, including those who have undergone prior HBO therapy. Thirty patients were selected with Marx stage III ORN of the mandible who underwent a complete debridement and microvascular reconstruction. Twenty-seven of 30 patients experienced successful resolution of their ORN. Complications were encountered in 13 of these cases, but the majority were self-limited and required only local flap coverage. Patients who received preoperative antibiotics had a lower incidence of free flap failure (0% vs. 22%; p = 0.04).
A limitation of this multi-institutional retrospective review is that only 3 patients in this cohort received perioperative HBO therapy. Thus, conclusions regarding the efficacy of perioperative HBO cannot be drawn. However, it is likely that this group of patients would benefit from a routine perioperative HBO regimen, and it is worth further investigation to determine which patients may most benefit from the use of this therapy in conjunction with free flap reconstruction.
Recurrence of ORN Following Free Flap Reconstruction
A systematic literature review of published studies assessing ORN recurrence following free flap reconstruction was undertaken. The study involved extensive exploration of the literature, meticulous screening of studies for inclusion and exclusion, quality assessment, and statistical analysis. Twenty-four studies were reviewed, and ORN recurrence was reported in five of them (Table 1).
Recurrent ORN occurs when the bone tissue fails to heal after radiotherapy treatment. It is a potentially serious complication of free flap reconstruction in patients with advanced orn. It can lead to impaired oral function, painful exposed bone, and loss of skeletal stability. In some cases, it can lead to additional surgical intervention and even death.
This is a complex disease, and it has a variety of signs and symptoms that include unhealed exposed bone in the jaw, pain, swelling, malaise, poor wound healing, oedema, and infection, which can be difficult to differentiate from cancer recurrence or other non-cancerous diseases. It is also associated with a decreased quality of life (QOL).
The main pathophysiological process in mORN involves microvascular thrombosis, neoendothelial cell damage, and subsequent bone breakdown and fibrosis. Many risk factors are associated with its development, including high dose ionizing radiation to the head and neck, prior radiotherapy surgery, smoking status, male gender, older age, alcohol consumption, and poor dental hygiene.
Microvascular free flap reconstruction is the standard of care in severe mORN cases. The most commonly used flap is the fibula flap, although other choices include the iliac crest flap, radial forearm flap, anterolateral thigh flap and the scapular flap5.
Preoperative evaluation and optimization of the patient’s medical conditions is important to improve flap success. Fluid maintenance is crucial to maintain blood flow to the flap, and it should be achieved through hyperdynamic fluid resuscitation (not to exceed 6 ml/kg/hour). This can be accomplished by a combination of colloid and crystalloid, and by maintaining normal urine output, adequate blood pressure, and an elevated haematocrit level (>30%). In addition, the surgeon should be skilled at performing a precise and thorough microvascular anastomosis.
Avoiding ORN Recurrence
While ORN is not preventable, there are several steps patients can take to decrease the likelihood of its occurrence. For one, it is important for them to follow their dentists’ instructions regarding oral hygiene, especially after radiation. It is also important to visit the dental office for regular exams and cleanings, as well as to get x-rays regularly. The latter will help them spot any problems, such as bone deterioration, early on and catch them before they develop into full-blown ORN.
In addition, patients who have had RT should consider taking calcium supplements to ensure sufficient bone mineralization. In a recent study, the use of calcium and vitamin D supplements was found to significantly reduce the risk of ORN in head and neck cancer patients following RT. Other strategies to avoid ORN recurrence include avoiding smoking and excessive alcohol consumption, which can lead to a decreased immune system.
ORN is a multifactorial condition and its incidence has been associated with tumor-related, treatment-related and patient-related factors. Tumor-related factors include tumor size, stage, and location. Treatment-related factors include radiation dose, RT technique, volume of the irradiated mandible, concurrent chemotherapy, and re-irradiation. Patient-related factors are tobacco and alcohol use, poor oral hygiene, periodontal disease, and dental extractions prior to or after RT.
Many patients with ORN are asymptomatic, which can make detection difficult. Often, it may be 5, 10, or even 20 years before the development of clinical signs. Signs of ORN can be seen on x-rays, which can reveal areas of exposed bone, or on computed tomography scans that can depict osteolytic lesions, sequestrum, and pathological fractures.
18F-FDG PET/CT imaging is a valuable tool to identify and distinguish ORN from cancer recurrence. Meerwein and colleagues have shown that a combination of three parameters–the minimum SUVmax value, the location of the SUVmax voxel within the bone, and the presence of a pathological fracture–are significant predictors for ORN. They have also identified a number of predictive genetic markers for ORN. This information could be used to identify patients who are at higher risk of developing this complication, and to guide preoperative planning and treatment for these patients.
Preoperative Planning for Free Flap Reconstruction
Free flap reconstruction can be complex and requires a high level of microsurgical skills. It involves the transfer of living tissue (ie, skin, muscle, bone or a combination) from one area of the body to another to repair defects due to disease or trauma. This procedure allows for the creation of a natural appearance with minimal scarring. However, it can result in lengthy operative times.
This is mainly due to the complexity of the procedure, as well as the fact that most patients require radiation and/or chemoradiation after surgery. The duration of the procedure is also increased by the risk of complications.
To address this issue, lean management techniques are being implemented in health care to identify areas for improvement and reduce the time waste. Lean techniques include process mapping and time studies. They help to break down a complex procedure into its components, so the team can understand what is driving OR time waste. They can then develop focused interventions to decrease the amount of time wasted during the surgical procedure.
In a recent study, lean techniques were used to identify efficiency improvement opportunities in head and neck free flap reconstruction cases. Using these methods, the researchers identified that a lack of effective communication was causing OR time waste. They designed a new document, the free flap plan of the day, to improve communication between surgeons, anesthesia, and nurses. The free flap plan of the day document is a checklist that captures key pieces of information required for each case.
The investigators then evaluated the impact of this new communication tool on OR times. They observed a decrease in OR times among patients who received the free flap plan of the day compared to those who did not. The authors conclude that the use of the free flap plan of the day can improve perioperative communication and lead to decreased OR time for free flap reconstruction.
In this study, the investigators analyzed data on 200 patients who underwent free flap reconstruction for various head and neck defects. They investigated the incidence and the clinical outcome of initial hyperemia, which is a reddish color change in the transferred flap that results from resuming tissue perfusion via microvascular anastomosis.