Spinal Microdecompression

Decompression of the lumbar spine for spinal stenosis is the most commonly performed spinal surgery procedure in people over 60 years old. The aims of surgery are to relieve pressure from the spinal nerves whilst retaining the supportive function of spinal column.

Some surgeons have reported poor outcomes and low incidences of long term success using traditional approaches.  One plausible explanation for the late deterioration is that traditional approaches involve some destruction of the the stabilising structures around the spinal canal.

This can lead to an unstable spine or recurrent symptoms, including pain. Lumbar spine “micro-decompression” aims to address this problem by approaching and entering the canal from one side only. After decompressing the first side/open side, the surgeon crosses to the opposite side beneath the overhanging bony structures, allowing a decompression to be done on the opposite side from within the canal.

All the bony and soft tissue structures outside the canal on the opposite side are preserved with no increase in surgery required to the side of canal entry.  Safety is further aided by the use of an operating microscope and specialised surgical instruments.

The results associated with this technique have been reanalysed and Mr Orpen has reported the outcomes in treating spinal stenosis with micro-decompression surgery in a group of 100 patients over a 6-year period (JBJS (Br) 2010).  Mr Orpen and his colleagues aimed to assess the safety and feasibility of this modified technique of bilateral decompression through a one-sided approach and compared it to existing evidence of traditional approaches.

Mr Orpen and his colleagues were also interested in the effects on stability of the lower (lumbar) spine in the longer term and assessed which patients developed symptomatic instability, requiring further stabilisation surgery.  This technique of lumbar micro-decompression has proved to be safe with few complications and good results after an average of 3 years 6 months and for up to 6 years and this looks encouraging for the longer term.

This technique has advantages over wide decompression in that it preserves the supportive anatomy without compromising safety and Mr Orpen continues to evaluate this technique over the long-term. Patients report less pain and are discharged home sooner and the rate of post-operative instability leading to fusion surgery is low and is certainly lower than the published series of traditional approaches.