Sulcus-Ulnaris-Syndrom: Einfache Dekompression oder subkutane Vorverlagerung?

Fortschr Neurol Psychiat 2007; 75 : 168 - 171

With great interest I read the paper by Nabhan and colleagues on their prospective randomised controlled study comparing subcutaneous anterior transposition with nerve decompression without transposition in patients with cubital tunnel syndrome [1]. I would like to congratulate the authors on their work, the more this is one of the few randomized prospective studies on this field.

The design of their study, a prospective randomised controlled study, for which approval was obtained by the local ethical committee, introduces some questions. The majority of the work, including their discussion, presented in Fortschr Neurol Psychiat was already published in the Journal of Hand Surgery 2 years earlier [2]. In Fortschr Neurol Psychiat the 2 year results are added. Because of the design of the study, I believe the term: ‘interim analysis’ should have been mentioned in their paper published in the J Hand Surg in 2005. And if the authors forgot to do this, why didn’t they mention this paper with exactly the same patient population in Fortschr Neurol Psychiat?

Furthermore, in their paper in the J Hand Surg of October 2005 the authors mentioned that to their knowledge, there has been no prospective randomized study comparing simple decompression with anterior subcutaneous transposition. In the same year in March, however, Bartels et al. published a prospective randomized controlled study comparing simple decompression versus anterior subcutaneous transposition in 152 patients [3]. This may have been missed, or caused by a delay with the journal between author proofs and publication, but why didn’t the authors mention this paper in their recent paper in Fortschr Neurol Psychiat? For the reader, the conclusion of the paper from Bartels and colleagues is of importance. They advised simple decompression because it is simpler and associated with fewer complications. As Nabhan and colleagues found no difference between the groups either this is of importance to the literature. It may be of interest to know if Nabhan and colleagues also found a higher complication rate in their subcutaneous transposition patient group.

Although there is nothing wrong with the design of the skin incision (8 cm long posterior to the medial epicondyle), another alternative may be to make the incision anterior to the medial epicondyle. A ‘simple’ decompression can then be easily converted to a transposition of the nerve for example if intraoperative subluxation of the nerve occurs with flexion of the elbow after decompression. In such cases an anterior incision may be of advantage when the incision needs to be enlarged (as the authors already mentioned: ‘with subcutaneous transposition it is sometimes difficult to obtain a complete tension free nerve in the new environment’). Did the authors not see a single subluxation in their series of 32 patients? On the other hand, maybe transposition is not even necessary in subluxation [3]. Another advantage of an anterior incision is the flap of skin and subcutaneous tissue on top of the operating field instead of a healing scar on top of the operating field.

Furthermore, Martin Boyer in 2006 wrote a commentary on Nabhan’s paper that appeared in J Hand Surg in 2005 [4]. Although I do not agree with Boyer’s statement that too blunt tools were used to measure clinical improvement, it is unclear why the authors did not handle the comments in their most recent paper on whether or not the patients had subluxation or dislocation of the nerve preoperatively and statements on study power and beta error.

Finally, it may be that the problem of the so called sulcus ulnaris syndrome is not only in or around the sulcus. Many authors published unsatisfactory results in approximately 15 %, independent on the technique used. This may be due to more distal pathology [5] [6]. Although not widely used, endoscopic cubital tunnel release may solve some of the distal compression problems [7]. A 30 mm skin incision is enough to decompress the nerve over a long distance (approximately 12 cm distally and 10 cm proximally).

Although there are several surgical treatments available for cubital tunnel syndrome, a consensus regarding optimal treatment has never been reached. With the studies of Bartels, and Nabhan there is now evidence favouring simple decompression as compared to anterior subcutaneous transposition [1] [3]. The same accounts for comparisons between simple decompression and anterior submuscular transpositions [8] [9]. If some surgeons still continue to be sceptical or talk about their ‘own experience’ they should provide the literature with their evidence. Whether or not endoscopic release of the ulnar nerve over a longer traject may improve the results of simple decompression remains to be unanswered at the moment, but the technique certainly has potential.

References

• 1 Nabhan A, Kelm J, Steudel W I, Shariat K, Sova L, Ahlhelm F. Cubital tunnel syndrome-simple nerve decompression or decompression with subcutaneous anterior transposition?.  Fortschr Neurol Psychiatr. 2007;  75 168-171
• 2 Nabhan A, Ahlhelm F, Kelm J, Reith W, Schwerdtfeger K, Steudel W I. Simple decompression or subcutaneous anterior transposition of the ulnar nerve for cubital tunnel syndrome.  J Hand Surg [Br]. 2005;  30 521-524
• 3 Bartels R H, Verhagen W I, Wilt G J van der, Meulstee J, Rossum L G van, Grotenhuis J A. Prospective randomized controlled study comparing simple decompression versus anterior subcutaneous transposition for idiopathic neuropathy of the ulnar nerve at the elbow: Part 1.  Neurosurgery. 2005;  56 522-530
• 4 Boyer M. Comment on: Simple decompression did not differ from simple decompression plus anterior transposition of the nerve for cubital tunnel syndrome.  J Bone Joint Surg. 2006;  88A 1893
• 5 Degeorges R, Masquelet A C. The cubital tunnel: anatomical study of its distal part.  Surg Radiol Anat. 2002;  24 169-176
• 6 Siemionow M, Agaoglu G, Hoffmann R. Anatomic characteristics of a fascia and its bands overlying the ulnar nerve in the proximal forearm: a cadaver study.  J Hand Surg [Br]. 2007;  32 302-307
• 7 Tsai T M, Chen I C, Majd M E, Lim B H. Cubital tunnel release with endoscopic assistance: results of a new technique.  J Hand Surg [Am]. 1999;  24 21-29
• 8 Biggs M, Curtis J A. Randomized, prospective study comparing ulnar neurolysis in situ with submuscular transposition.  Neurosurgery. 2006;  58 296-304
• 9 Gervasio O, Gambardella G, Zaccone C, Branca D. Simple decompression versus anterior submuscular transposition of the ulnar nerve in severe cubital tunnel syndrome: a prospective randomized study.  Neurosurgery. 2005;  56 108-117