We thank Oh et al. for raising the idea that these cases may represent Morel-Lavallee lesions (MLLs). Certainly, there are some similarities such as soft swelling with intact skin, and no skin changes. However, MLLs are typically degloving injuries associated with high force trauma and rarely affect the head. Even allowing for the retrospective nature of our study, there was no suggestion of such severe trauma in any of our cases. Similarly, the significant risk of MLLs becoming organized, forming a capsule, or becoming infected was not seen in our series. The classification of such lesions based on magnetic resonance imaging appearances will be problematic in swellings around a cochlear implant package because of the magnetic shadow.

A similar low-force shearing injury leading to tearing of small vessels may be a plausible mechanism for some cases, but without thorough prospective evaluation of such cases including blood tests, ultrasound imaging, and aspiration, the etiology may be difficult to prove. We suspect that there are multiple different underlying etiologies, of which minor trauma is one. Shen et al. (1), in their literature review of MLL, suggest that surgical treatment is preferable to conservative management, although these cases seem to be larger lesions in the orthopedic field. Certainly, we would not recommend open incision and drainage for cochlear implant swellings unless there is definitive evidence of infection, and it is reassuring to know that none of our cases have developed definite infection or required explantation.

Zara Shaida, M.B., B.S.
Department, Charing Cross Hospital, Fulham Palace
Road, London, UK
Tiarnan Magos, F.R.C.S., O.R.L.-H.N.S.
Hala Kanona, F.R.C.S., O.R.L.-H.N.S.
Azhar Shaida, B.M. B.Ch., F.R.C.S., M.D.
RNENTEDH/UCLH, 47 Huntley Street, London, UK
[email protected]

1. Shen C, Peng JP, Chen XD. Efficacy of treatment in peri-pelvic Morel-Lavallee lesion: A systematic review of the literature. Arch Orthop Trauma Surg 2013;133:635–40.