HIV Posterior Cheek Enlargement

BACKGROUND AND SIGNIFICANCE

Altered contour of the lower face is a frequent complication of HIV and can lead to significant cosmetic disfigurement and social stigmatization. However, posterior cheek enlargement in HIV is poorly characterized. The parotid and masseter overlie the mandibular ramus, thus both contributing to the lower facial contour. Parotid hypertrophy is a recognized and common complication of HIV. It is presently unknown whether masseter muscle hypertrophy also contributes to this cosmetic deformity. The investigators will conduct a prospective pilot study in HIV+ patients to determine whether masseter muscle hypertrophy and parotid gland enlargement contribute to a bulky and widened lower facial contour, or whether the aesthetic appearance is due primarily to apparent muscle enlargement attributable to facial lipoatrophy.

Development of novel treatments to address these HIV-associated cosmetic changes is increasingly important as the burden of this disease expands globally. There have been limited advances in salivary gland surgery in recent years. The benign nature of parotid gland hypertrophy requires the surgeon to preserve key anatomical structures as an important marker of outcome. As such, parotidectomy is a controversial procedure. Treatments for masseter hypertrophy include surgical reduction of the masseter muscle and resection of the mandibular angle to create a narrower facial width. These surgical treatments can involve significant complications such as facial nerve injury, infection, scarring, bleeding, swelling and trismus. This highlights the need to develop more treatments for posterior cheek enlargement. Botulinum toxin is a highly efficacious and cost-effective, nonsurgical option for reducing the width and improving the shape of the lower face and jawline. Botulinum toxin for masseter hypertrophy and parotid enlargement in HIV negative individuals and sialorrhea in neurological disease is a safe and effective treatment for these conditions. However, there are no studies published to date on the use of botulinum toxin in the setting of HIV. Furthermore, the investigators have already demonstrated the efficacy of using botulinum toxin A in the treatment of posterior cheek enlargement in a trial HIV+ patient with both parotid enlargement and masseter hypertrophy. This patient had a dramatic response clinically and demonstrated a 19.0% and 19.4% mean reduction in the volume of the parotid gland and masseter muscle, respectively, 12 weeks after injection of botulinum toxin A. He experienced no adverse effects from the injections.

The investigators will use clinical, photographic and radiological evaluations to determine the efficacy and durability of botulinum toxin A for altered lower facial contour in HIV+ patients. The investigators anticipate that, at a minimum, this study will improve our understanding of posterior cheek enlargement seen in some HIV+ patients. The results of this study may translate into a novel and evidence-based use of botulinum toxin for management of altered lower facial contour in HIV+ patients. This could potentially improve the psychosocial wellbeing in patients afflicted with this devastating disease.

STUDY PROTOCOL

This will be an initial pilot study with 5 participants. Participants with posterior cheek enlargement will have photographs taken and a baseline CT scan of the head performed. Botulinum toxin A will be injected by identifying the inferior border of the zygomatic arch and mandibular ramus as well as the anterior and posterior demarcation of the posterior cheek enlargement. Injections will be performed percutaneously by palpation. A total of 10 U will be injected into 5 evenly spaced points of the posterior cheek enlargement to give a total dose of 50 U per side.

Participants will be evaluated clinically at 4, 8 and 12 weeks after injection, with photographs, and by a questionnaire assessing patient satisfaction and side effects. A CT scan of the head will be performed 12 weeks after injection of botulinum toxin A. Long-term efficacy of botulinum toxin A will then be evaluated at 6 and 12 months post injection clinically, with photographs and a questionnaire assessing patient satisfaction and side effects.

The primary outcome will be the change in volume of the masseter muscle and parotid gland 12 weeks after treatment with botulinum toxin A. The mean change and standard deviation will be determined. A secondary outcome will be the relative contributions of masseter hypertrophy and parotid enlargement to posterior cheek enlargement in HIV+ patients. The pre-treatment volume of the masseter muscle and parotid gland determined in our HIV+ participants will be compared to those of normal controls published in the literature.