Removal of nucleus pulposus from the intervertebral disc – the use of chymopapain enhances mechanical removal with rongeurs: a laboratory study

Lei Dang¹ , Douglas Wardlaw² and David WL Hukins¹

¹School of Engineering, Mechanical Engineering, University of Birmingham, Birmingham, UK

²Department of Orthopaedic Surgery, Woodend Hospital, Aberdeen, UK

author email corresponding author email

BMC Musculoskeletal Disorders 2007, 8:122doi:10.1186/1471-2474-8-122


Published:	13 December 2007

Abstract

Background

A laboratory study was conducted, on cadaveric sheep spines to develop an effective procedure for removing as much nucleus as possible from an intervertebral disc with minimal disruption to the annulus. The results of many studies involving removal of nucleus, including chemonucleolysis, using chymopapain, have been published but we are not aware of any previous quantitative studies on procedures for removing as much nucleus as possible from the disc.

Methods

All procedures were performed via a 3 mm trocar. Four procedures were compared: (I) unilateral approach using rongeurs alone, (II) bilateral approach using rongeurs alone, (III) unilateral approach using rongeurs followed by chymopapain and (IV) bilateral approach using rongeurs followed by chymopapain.

Results

The percentages of nucleus removed were: (I) 34%, (II) 41%, (III) 52% and (IV) 75%; there were significant differences between the four sets of results according to ANOVA.

Conclusion

Significantly more nucleus is removed using a bilateral than a unilateral approach; significantly more nucleus is removed if chymopapain is used in addition to rongeurs. A brush is useful in removing strands of nucleus loosened by chymopapain.