Have you ever lost your sense of smell or taste? Recall how it feels when your face/mouth don’t work properly until the nerve blocks wear off after a dental procedure.
Those are all things (and more) a facial transplant patient has to deal with. The article discussing recovery of sensation after facial transplantation in the May issue of Plastic and Reconstructive Surgery discusses this topic (first reference below).
In addition to reviewing their own face transplant patients (n=4), Dr. Maria Siemionow and colleagues did a literature review (English literature for peer-reviewed articles published between 1940 and 2010) of sensory recovery after various standard nerve repair techniques.
These other nerve repair techniques included repair of the peripheral branches of the trigeminal nerve; sensory return after free tissue transfer (ie noninnervated flaps, including radial forearm, lateral thigh, anterolateral thigh, latissimus dorsi, trapezius, et al and innervated free flaps, including radial forearm, anterolateral thigh, and rectus abdominis musculocutaneous flaps); and sensory recovery following replantation of scalp and forehead.
(1) Direct sensory nerve growth through microsurgical nerve repair.
(2) Trigeminofacial communications.
(3) Nervi nervorum of the facial nerve.
(4) Somatic afferents of the facial nerve.
(5) Adrenergic plexus of the vascular pedicle.
Siemionow and colleagues report that only one of the four face transplant recipients underwent direct repair of the sensory nerves. In the other three cases, it was impossible to reconnect the nerves because of technical difficulties or the severity of the patient's injuries.
Even so, all four patients began regaining sensation in the transplanted face as early as two weeks after surgery and had normal or near-normal sensory function by the end of the first year.
The extent of recovery was similar to that achieved with simple repair of injured sensory nerves in the face-and even better than that of grafting procedures where tissues are transferred to the face from different areas of the body without reconnecting the nerves.
Siemionow and colleagues note in their discussion:
Based on the results of our comparative analysis, we can conclude that, in the absence of extensive soft-tissue injury, simple repair of facial sensory nerves leads to restoration of nearly normal sensation. ….. Interestingly, face transplantation is the only clinical condition where, in the absence of sensory nerve repair, good functional outcome is achieved despite severe trauma causing soft-tissue and sensory nerve damage.
As they also note (bold emphasis is mine)
An important issue that emerged from the comprehensive review of the literature is an evident lack of universal methods of neurosensory assessment and an urgent need for establishment of guidelines that will help with comparative analysis of the sensory recovery data. This applies to the reported cases of face transplantation, where documentation of sensory recovery is either marginal or overlooked.
For the face transplants, as with head injury patients, the olfactory nerve function needs to be assessed as well and it wasn’t in this study. If the person can’t smell smoke or gas leaks, then extra care or caution has to be taken at home.
Pathways of Sensory Recovery after Face Transplantation; Siemionow, Maria; Gharb, Bahar Bassiri; Rampazzo, Antonio; Plastic & Reconstructive Surgery. 127(5):1875-1889, May 2011; doi: 10.1097/PRS.0b013e31820e90c3
Discussion: Pathways of Sensory Recovery after Face Transplantation; Chong, Tae; Plastic & Reconstr Surgery 127(5):1890-1891, May 2011; doi: 10.1097/PRS.0b013e31820e88c9
ASPR Press Release, May 9, 2011: Sensation Recovers to 'Near-Normal' After Face Transplant, Study Finds
Setting Goals, Rehabilitating After Brain Injury; NPR, May 16, 2011