gms | German Medical Science

54. Jahrestagung der Norddeutschen Orthopädenvereinigung e. V.

Norddeutsche Orthopädenvereinigung

16.06. bis 18.06.2005, Hamburg

Comparison of soft tissue trauma in microsurgical nucleotomy to a new technique - microscopically assisted percuteaneous nucleotomy: an MRI-study

Meeting Abstract

  • corresponding author J. Franke - Orthopädische Universitätsklinik Magdeburg, Magdeburg
  • H. Boehm - Bad Berka
  • B. Hempel - Bad Berka
  • J. Leonhardi - Bad Berka
  • R. Greiner-Perth - Gera

Norddeutsche Orthopädenvereinigung. 54. Jahrestagung der Norddeutschen Orthopädenvereinigung e.V.. Hamburg, 16.-18.06.2005. Düsseldorf, Köln: German Medical Science; 2005. Doc05novEP117

Die elektronische Version dieses Artikels ist vollständig und ist verfügbar unter:

Veröffentlicht: 13. Juni 2005

© 2005 Franke et al.
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Microsurgical nucleotomy (MC) currently is regarded as „gold standard" in the operative treatment of lumbar disc herniation. This prospective randomised study aims at comparing the trauma of the approach of the standard technique to a newer method working through a working channel under control of the surgical microscope: "microscopically assisted percutaneous nucleotomy" (MAPN). Instead of detaching from the spinous processes as in MC in MAPN technique through a 15mm skin incision the paraspinal muscles fibres are gently spread by two dilators. Then a threaded working channel with an outer diameter of 11mm is inserted by clockwise rotation. All further steps are done under the operative microscope.

The objective was to determine whether or not MAPN was less invasive with respect to the nerve roots and the paravertebral muscles by comparing the postoperative MRI findings in patients treated by MAPN and the microsurgical discectomy.

Material and methods

This is a prospective, randomized and blinded study examining fifty patients. Two subgroups were randomly selected for either of the treatment options. Magnetic resonance imaging with application of contrast medium (Gd-DTPA) was performed on every patient immediately before surgery and within the first 48 hours after the intervention.

Enhancement of the nerve roots, edema of the paravertebral muscles, as well as the maximum extension of seroma/haematoma were assessed on axial T1-weighted and T2-weighted magnetic resonance images. To compare the size of edema between both groups we measured the angle between the route of surgical access and the lateral margin of edema.

Results: There was no relevant difference of enhancement of the nerve roots between both groups. However a significantly (p<0.001) smaller angle of edema extension could be measured in MAPN (22.36°; SD 7.8) when compared to MC (38.6°; SD 9.3). The maximum extension of seroma/hematoma in the approach area with a mean value of 33.4mm2 in MAPN did also show a statistically significant (p<0.05) difference to MC, where the average amounted to 134.8 mm2 . These findings go parallel with a distinctly (p<0.001) smaller need for analgesics (in the early postoperative course: 1.3mg morphine equivalents in MAPN and 5.4mg in MC during the first 48 hours after surgery.


Noninvasive assessment of muscle trauma imposes substantial problems. Certainly changes in the signals of Magnetic Resonance cannot be equalled with surgical trauma, but they denote an alteration of the tissue due to the intervention. So it seems justified, to draw conclusions from different areas affected in a two-dimensional study. The 4 fold bigger area altered due to the microsurgical approach and the significantly smaller need for pain killers seems to justify the conclusion, that the working channel technique of MAPN is less invasive and may be a proper alternative. Further investigations in other institutions are under way to increase the data basis.