Resolution of Pneumomediastinum, Cervicofacial Emphysema, and Internal Ophthalmoplegia with Hyperbaric Oxygen Therapy After Hip Arthroscopy: A Case Report.

Background/Objectives: Hip arthroscopy is a minimally invasive procedure with rare complications that can occur due to air entry outside the joint space. Case Presentation: A 19-year-old patient underwent right hip arthroscopy with attempted joint venting. The next morning, she had pain in her right leg, neck, and chest with paresthesias over her hands and feet. A subsequent emergency department physical exam revealed crepitation of the lower extremities, abdomen, chest, and neck caused by air entrance during arthroscopy. The patient also reported blurred near vision. Additionally, the pupils were fixed, did not accommodate, and were dilated at 7 mm. Computed tomography scans revealed subcutaneous emphysema, pneumoperitoneum, pneumomediastinum, and cervicofacial emphysema. Magnetic resonance imaging of the brain revealed a Chiari I malformation. The patient received four hyperbaric oxygen treatments. By the fourth treatment, near visual acuity had improved, but far visual acuity had worsened. Vision had returned to normal eight days after discharge. Conclusions: It is proposed that the patient's reduced near vision, accommodation paralysis, and fixed and dilated pupils were brought about by pneumomediastinum and cervicofacial emphysema, inhibiting the ability of the pupils to constrict, causing bilateral mydriasis and accommodation paralysis for near targets. Additionally, the subsequent transient myopic shift is a known complication of hyperbaric oxygen therapy, which increases the refractive index of the crystalline lens.