Far-Lateral Approach to Lumbar Peripheral Nerve Sheath Tumors

Martin Zonenshayn, MD
Michael H. Lavyne, MD (New York, NY)

Introduction:

The herniated intra– and extraforaminal lumbar disc, commonly referred to as a "far–lateral" disc, has been surgically addressed via several "extra–canalicular" approaches. We describe the use of some of these approaches in the management of small lumbar peripheral nerve sheath tumors.

Methods:

Various surgical approaches to these lesions have been described, including a hemi–laminectomy with total or subtotal facetectomy, intertransverse approaches (via either a paraspinous muscle splitting or the standard paramedian trajectory), and a true posterolateral route. We employed the intertransverse route in 2 patients and will describe the advantages and disadvantages of this method for removing extradural, intra– and extra–canalicular nerve sheath tumors. In the first patient we resected a small left L2 melanocytic schwannoma via the paramedian approach to the intertransverse space. This exposure allowed for a possible laminotomy in the event that intraspinal access was required in order to completely resect the lesion. In a second patient with a right L3–4 dumbbell–shaped schwannoma the extra–canalicular portion of the tumor was resected using the muscle splitting intertransverse route to the neural foramen.

Results:

Both patients described were immediately relieved of their radiculopathy and have returned to work.

Conclusion:

While only 6 month follow–up is currently available, the previously described far–lateral approaches to an extra–canalicular herniated disc can be safely and effectively employed in the management of tumors in this area with minimal bony resection and risk of postoperative instability.