Face-down positioning after silicone or gas tamponade for retinal surgery is an established practice mainly for upper retina beaks and posterior pole surgery. The use of long-acting gases for conventional retinal surgery and vitrectomy is subjected to some restrictions regarding gas concentration, altitude [¹], airplane travel [², ³, ⁴], and general anesthesia [⁵]. However, no guidelines for surgeons exist concerning the duration of face-down positioning. Strict face-down positioning after use of long-acting gas or silicone tamponade bears the risk of ulnar neuropathy [⁶, ⁷, ⁸]. This case report draws attention to this risk.

A 57-year-old, overweight woman presented to the eye casualty department complaining of flashing lights, floaters, and decreased visual acuity in the left eye. Best-corrected decimal visual acuities were 10/10 OD and 7/10 OS. Fundus examination revealed an upper temporal bullous rhegmatogenous retinal detachment emanating from a hole along the border of a lattice degeneration. A 23-gauge vitrectomy with 16% SF6 gas tamponade was performed. The patient was instructed to assume a face-down position for 10 days.

Two weeks later, she was complaining of hypoesthesia and numbness along the left 4th and 5th finger, as well as hypoesthesia, numbness, and a burning sensation along the right 4th and 5th finger. An appointment with the orthopedic clinic was arranged for her, and a bilateral ulnar nerve neuropathy was diagnosed. Six months later, a surgical intervention with decompression of the right ulnar nerve at the elbow was performed due to progressive deterioration of symptoms (fig.1).

One year later, she still complained of bilateral hypoesthesia and numbness in the 4th and 5th fingers and ‘weak grip’ in the right hand.

In 1996, Ciulla et al. [⁶] reported 2 cases of ulnar nerve palsy after maintaining a face-down position for 2-4 weeks after vitrectomy with intraocular perfluorooctane. One of the patients underwent surgical decompression of the nerve at the elbow. In 1999, also Holekamp et al. [⁷] reported 7 cases of ulnar neuropathy during the immediate postoperative period after vitrectomy with fluid gas exchange for macular hole surgery followed by at least 1 week of strict face-down positioning. All patients had persistent symptoms during a follow-up period ranging from 3 to 24 months.

In 2004, Salam et al. [⁸] reported another case of bilateral ulnar neuropathy at the elbow confirmed by reduced conduction velocities in nerve conduction studies with minimal recovery during a follow-up period of 10 months.

In our case, the postoperative instructions included 10 days face-down positioning, and the symptoms started 2 weeks after surgery. The patient was overweight, and it is possible that the pressure on the bent elbow during face-down positioning was therefore increased.

As there are no specific guidelines for surgeons, patients must be instructed to minimize the time spent with their elbows in a flexed position to avoid any undue pressure on the elbows during face-down positioning. Moreover, patients should be made aware of warning signs of any early ulnar nerve damage symptoms, such as hypoesthesia, numbness, and a burning sensation in the 4th and 5th fingers.