Surgical treatment of spontaneous anterior interosseous nerve palsy: A comparison between minimal incision surgery and wide incision surgery

Abstract

Recent reports have suggested that fascicular constriction located proximal to the elbow may be the primary aetiology of spontaneous anterior interosseous nerve palsy (sAINP), and recommended interfascicular neurolysis ranging from the proximal forearm to distal upper arm (wide incision surgery: WIS) for its treatment. On the basis of these reports, it was hypothesised that, if the aetiology of sAINP was fascicular constriction, neurolysis limited proximal to the elbow (minimal incision surgery: MIS) should have similar results to those of WIS. Twenty-five surgically treated sAINP cases were retrospectively evaluated. The mean age of onset was 42.8 years, the mean preoperative period was 5.3 months, and mean follow-up period after operation was 31 months. Eleven patients underwent MIS, while 14 underwent WIS according to the patient's intention (intention-to-treat). Twenty-one patients had fascicular constriction, and no entrapment neuropathy was seen in this series. At the latest follow-up, 82% of the patients had British Medical Research Council grade of ≥4 in flexor-pollicis-longus, while 80% had grade of ≥4 in flexor-digitorum-profundus-of-the-index-finger. There were no significant differences between the results of either group. These result suggested that the aetiology of sAINP may not be external compression, but fascicular constriction, and MIS may be its favourable surgical treatment.

Key Words::

• Spontaneous anterior interosseous nerve palsy
• anterior interosseous nerve syndrome
• anterior interosseous nerve palsy
• compression neuropathy
• median nerve palsy
• fascicular constriction
• idiopathic
• interfascicular neurolysis
• minimal invasive surgery
• fascicular torsion

Acknowledgement

We thank Dr T. Koyanagi for helping us with statistical analysis. We also thank Dr M. Kihara, Dr T. Koyanagi, Dr Y. Kikuchi, Dr N. Nakamichi, Dr K. Morita, Dr H. Morisue, Dr S. Harato, Dr K. Takeda, Dr K. Ninomiya, Dr E. Okada, Dr T. Hasegawa, Dr H. Tanikawa, and Dr M. Okubo at the Department of Orthopaedic Surgery, Kawasaki Municipal Kawasaki Hospital. We also thank Professor Y. Toyama, Dr K. Uchinishi, Dr Y. Itoh, Dr T. Urabe, Dr H. Ikegami, Dr T. Nakamura, Dr K. Sato, Dr H. Saito, Dr N. Okuyama, Dr M. Okazaki, Dr T. Takagi, Dr T. Iwamoto and other members in the Hand Surgery group, Keio University School of Medicine, for helpful discussions. We also thank Professor S. Momohara, Dr K. Ikari, and all the members at the Institute of Rheumatology, Tokyo Women's Medical University for their support.