Immediate postoperative non‐invasive positive pressure ventilation following midface microvascular free flap reconstruction

Abstract Background There is a rare need for postoperative non‐invasive positive pressure ventilation (NIPPV) following microvascular reconstruction of the head and neck. In midface reconstruction, the free flap vascular pedicle is especially vulnerable to the compressive forces of positive pressure delivery. Case A 60 year old female with Amyotrophic Lateral Sclerosis (ALS) presented with squamous cell carcinoma of the anterior maxilla, for which she underwent infrastructure maxillectomy and fibula free flap reconstruction. To avoid tracheotomy, the patient was extubated postoperatively and transitioned to NIPPV immediately utilizing a full‐face positive pressure mask with a soft and flexible sealing layer. The patient was successfully transitioned to NIPPV immediately after extubation. The free flap exhibited no signs of vascular compromise postoperatively, and healed very well. Conclusion Postoperative non‐invasive positive pressure ventilation can be successfully applied following complex microvascular midface reconstruction to avoid tracheotomy in select patients without vascular compromise of the free flap.


| INTRODUCTION
There has been increasing evidence that tracheotomy is not required for a subset of head and neck cancer patients who undergo free flap reconstruction. [1][2][3] Avoidance of tracheotomy simplifies postoperative recovery, allows for early post-operative phonation, avoids complications of tracheotomy, and potentially shortens the postoperative hospital stay. [3][4][5] However, decision-making regarding perioperative tracheotomy is multifactorial and must incorporate the anticipated volume of the ablative defect and reconstruction, expected postoperative swelling, and underlying patient morbidities and body habitus.
In particular, amyotrophic lateral sclerosis (ALS) poses challenges for airway management following free flap head and neck cancer reconstruction. ALS is a neuromuscular disease of the upper and lower motor neurons that causes progressive respiratory insufficiency. 6,7 Tracheotomy in ALS patients is generally reserved for end-stage disease and should be avoided unless absolutely necessary given known difficulty with decannulation. This imperative is further complicated by the fact that ALS patients underoing anesthesia in general have a high risk of prolonged postoperative intubation and hospitalization after surgical procedures. 8,9 Non-invasive positive pressure ventilation (NIPPV) is frequently used for ALS patients to faciliate transition off the ventilator following extubation from general anesthesia. For the reconstructive head and neck surgeon, NIPPV poses a risk to the microvascular pedicle; as such, pedicle location and geometry are critical factors to consider when expecting to apply NIPPV postoperatively. Furthermore, NIPPV is frequently used as an important adjunct for ALS patients in general to improve quality of life and life expectancy. [10][11][12] Thus, the treating surgeon must be prepared to navigate use of a NIPPV system around the microvascular reconstruction.
Here we highlight a clinical case of midface microvascular reconstruction in an ALS patient with squamous cell carcinoma of the anterior maxilla to demonstrate techniques for protecting the microvascular reconstruction when tracheotomy should be avoided and NIPPV is required postoperatively.

| CASE 1
Written, informed consent for the publication of case details and identifying photographs and radiographs was provided by the patient.

| Clinical Presentation
A 60 year old female presented to Head and Neck Clinic with a 3-4 month history of a lesion of the anterior alveolar ridge. Biopsies revealed invasive squamous cell carcinoma (SCC). Clinically, she had a 4 cm lesion of the anterior maxilla, and radiographically the tumor eroded just through the floor of the nasal cavity but did not approach the orbit (Figure 1). Her case was discussed at multidisciplinary tumor board, with consensus recommendation for upfront surgery via infrastructure maxillectomy.
The patient was diagnosed with slowly progressive limb-onset familial ALS 3 years prior to this cancer diagnosis, with subsequent onset of respiratory and bulbar symptoms. At the time of presentation, she was wheelchair-bound, partially gastrostomy tube dependent (tolerating only limited pureed food by mouth), requiring symptom management for sialorrhea, and using NIPPV at night for orthopnea with normal speech function. Pre-operative pulmonary function testing showed a vital capacity of 51% of predicted normal. Given the underlying respiratory insufficiency due to her ALS, there was concern that the patient would be difficult to decannulate should she undergo tracheotomy perioperatively, and that by doing so she would be prematurely committed to lifetime tracheotomy F I G U R E 1 Representative preoperative coronal (A) and axial (B) computerized tomography slices of the tumor of the anterior maxilla crossing midline F I G U R E 2 Intraoperative photos of two-segment osteocutaneous fibula free flap midface reconstruction (A); free flap pedicle tunneled medial to mandible (arrow) prior to microvascular anastomosis with the facial artery and vein (B); and postoperative appearance of the patient's midface and well-vascularized free flap skin paddle at the finalization of the case (C) dependence. The patient was admitted pre-operatively to optimize her overall status and evaluate if her NIPPV face mask could be incorporated post-operatively. Multi-disciplinary input between the surgical team, neurology, respiratory therapy, anesthesia, speechlanguage pathology, and patient resulted in a consensus decision to attempt to avoid a tracheotomy.

| Surgical Details
The patient underwent an uncomplicated infrastructure maxillectomy, ipsilateral neck dissection, and fibula free flap reconstruction via a two-surgeon synchronous approach to minimize operative time. Twosegment vascularized bony reconstruction was utilized to reconstruct the anterior maxilla ( Figure 2). The 5 Â 10 cm fibula skin paddle was utilized for reconstruction of palatal, alveolar, buccal, and lip mucosa.   The head and surgeon should carefully counsel a patient with ALS that decannulation following tracheotomy for a non-pulmonary purpose (eg, airway protection following head and neck reconstruction) may be prolonged and/or more difficult than the typical head and neck cancer patient. In this case, a tracheotomy was avoided by transitioning the patient directly from the ventilator to NIPPV as she recovered from general anesthesia, and we encountered no issues with airway compromise postoperatively. Additionally, it allowed for immediate oral speech which was her perferred mode of communication in the setting of declining function of her upper extremities.
Patients with ALS ultimately lose the ability to phonate and rely on assistive modes of communication, which may be impacted by surgery. Ultimately, multidisciplinary discussions between the surgeon, pulmonologist, anesthesiologist, neurologist, respiratory therapist, speech-language pathologist, and nursing staff are critical for difficult perioperative decision-making for these patients.

CONFLICT OF INTERESTS
The authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest or nonfinancial interest in the subject matter or materials discussed in this manuscript.

ETHICAL STATEMENT
Written, informed consent was obtained directly from the patient for publication of this case and all photos included therein. Given that this manuscript includes the description of one single case, it does not meet criteria for "human subjects research" and as such is exempt from IRB review.

DATA AVAILABILITY STATEMENT
The data that support the findings of this study are available from the corresponding author upon reasonable request.