gms | German Medical Science

GMS German Plastic, Reconstructive and Aesthetic Surgery – Burn and Hand Surgery

Deutsche Gesellschaft der Plastischen, Rekonstruktiven und Ästhetischen Chirurgen (DGPRÄC)
Deutsche Gesellschaft für Verbrennungsmedizin (DGV)

ISSN 2193-7052

Multiple digital branch involvement of the median nerve by schwannoma: case report

Case Report

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  • corresponding author Julia Reinke - Department of Plastic, Hand and Reconstructive Surgery, Burn Center, Hannover Medical School, Hannover, Germany
  • author Andreas Gohritz - Department of Plastic, Hand and Reconstructive Surgery, Burn Center, Hannover Medical School, Hannover, Germany
  • author Peter M. Vogt - Department of Plastic, Hand and Reconstructive Surgery, Burn Center, Hannover Medical School, Hannover, Germany

GMS Ger Plast Reconstr Aesthet Surg 2012;2:Doc02

doi: 10.3205/gpras000004, urn:nbn:de:0183-gpras0000047

This is the original version of the article.
The translated version can be found at: http://www.egms.de/de/journals/gpras/2012-2/gpras000004.shtml

Published: February 9, 2012

© 2012 Reinke et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.


Abstract

A case of multiple digital branch involvement of the median nerve by a schwannoma is described in this case report. The benign tumor had grown for almost 30 years and infiltrated the digital nerves 1, 2 and 3. As a result the patient’s daily life activities became increasingly affected. After examination and definite evaluation of the tumor entity being a schwannoma, planning of the surgical treatment strategy included total resection of the schwannoma formations and the affected nerves. In a single-step-operation the nerves were grafted using a sural cable graft which was harvested from the right calf and divided into three nerve grafts.

During the 4-year clinical follow-up the patient showed no loss in grip strength and pinch grip strength. The two-point static discrimination revealed 8 mm for N1 and N2, 9 mm for N3 and 7 mm for N4. Subjectively his use of the affected hand was unlimited.


Case report

Schwannomas are the leading primary solitary tumors among peripheral nerves. These tumors are characterized by benign growth and originate from Schwann cells. From a surgical standpoint, schwannomas are usually easily prepared and separated from the surrounding tissue. The gold standard of treatment is the complete resection using an extracapsular or intracapsular approach [1], [2]. Nonetheless, large tumors involving distal, digital areas can be treated by surgical debulking prior to resection or an aggressive approach with radical resection including the nerve and its reconstruction using homografts [1], [2]. Involvement of multiple digital areas has as far as we know not yet been reported.

A 59-year-old, right-handed male patient presented in 2006 with a tumor on the flexor aspect of his right hand. The physical examination revealed a localized swelling of the radial palm, thumb and index finger following the course of the digital nerves N1, N2 and N3 distal to the carpal tunnel. MRI is considered to be the gold standard of all diagnostic procedures. The tumor occurred in the thenar region of N1, N2 and N3 extending to the metacarpophalangeal joint of the index finger and to the interphalangeal joint of the thumb (Figure 1 [Fig. 1]).

After the analysis of the MRI there was a strong suspicion, that the tumor was a benign schwannoma of the digital nerves descending from the median nerve. Due to microfascicular involvement resection without destruction of the digital nerve was impossible. Based on the preoperative MRI a radical resection of the digital nerves and the transplantation of nerve grafts were favored to remove the whole tumor (Figure 2 [Fig. 2]).

In a single-step-operation the indication for a nerve resection and reconstruction by nerve grafts was confirmed. The nerves were grafted using a sural cable graft which was harvested from the right calf and divided into three nerve grafts (Figure 3 [Fig. 3]).

Histopathologic examination of the tumor revealed a schwannoma (Figure 4 [Fig. 4]).

In January 2010 the patient demonstrated full motor recovery after neurolysis of the motoric branch and has no evidence of recurrent disease. There was a reduced sensitivity on the radial side of the index finger and on the ulnar side of the thumb. The two-point static discrimination revealed 8 mm for N1 and N2, 9 mm for N3 and 7 mm for N4. The grip strength testing of the right hand revealed almost as good strength levels as the left hand (33 kg vs. 34 kg). The pinch grip strength was identical on both sides (7 kg). Subjectively, the patient is very satisfied with the functional and aesthetic result of the procedure and accepts the residual marginal functional limitations due to reduced sensitivity.

The entity of a schwannoma is usually benign, relatively slow growing and only less than 1% metastasize. In this case all typical characteristics of a benign schwannoma growth were found, no metastases were diagnosed. Apart from genetic disposition, traumatic and non-traumatic incidences are potential reasons to cause a schwannoma. Bearing these facts in mind, fundamental research and clinical studies need to be performed to understand the pathogenesis of this tumor entity. Schwannoma growth is characterized by displacing the neural structures, thereby causing damage and dysfunction like hyposensibility, decreased motor function and dysaesthesia.

Schwannomas can usually be resected in toto using microscope magnification [1], [2]. Nonetheless major diagnostic findings – such as seen above – can be treated with debulking or a nerve interposition after digital nerve resection [1], [2]. The indication for a nerve interposition should be evaluated carefully since the expected outcome after resection of a benign tumor with a nerve graft reconstruction should be superior to other therapeutic options.

This case is special because the extent of the Schwann-Cell proliferation causing clinical problems prevented a nerve-sparing tumor resection. Since it was impossible to separate and prepare the tumor from the affected nerve fascicles, cable-grafting of the affected nerves after complete resection using a sural nerve graft was indicated.

Usually schwannomas occur as single tumors, but multiple incidences have been reported, too [3], [4]. In this case the length of the tumors was up to 10 centimeters and the width was 2 cm at the widest (Figure 4 [Fig. 4]).

The tumor usually occurs as a painless, asymptomatic mass, that grows slowly for several years without any clinical ailment, as seen in our patient. But pain, paraesthesia and motor weakness may occur later on if the tumor is not taken out, but reaches sufficient size.

Fortunately we could offer our patient a sufficient therapy off the gold standard therapy – which would be resection of the tumor without digital nerve resection –, which led to a very satisfying clinical outcome.

Even though the outcomes of the surgical interventions are encouraging, the risk of a relapse is still present. In our case there has been no relapse for the past four years potentially due to the applied operation technique.

We propose that the use of a sural cable graft represents an intervention which is indicated for the treatment of a schwannoma of the shown extent and therefore cannot be completely resected obeying surgical oncologic aspects.


Notes

Conflicts of interest

All named authors hereby declare that they have no conflicts of interest to disclose.


References

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Kang HJ, Shin SJ, Kang ES. Schwannomas of the upper extremity. J Hand Surg Br. 2000 Dec;25(6):604-7. DOI: 10.1054/jhsb.2000.0472 External link