Review Question - QID 217003

The clinical presentation and MRI image demonstrate a right-sided far lateral disc herniation at L4/5. A paraspinal muscle-splitting approach to the intertransverse space and discectomy would be the most appropriate operative treatment.

When performing a laminectomy/laminotomy, there is a limit to the degree of foraminal decompression that can be achieved. In the setting of a far lateral disc herniation, such as in the patient above at L4/L5, an approach that allows access to the lateral aspect of the facet joints is necessary. As opposed to a paracentral disc herniation, which at L4/L5 would affect the L5 nerve root (i.e. traversing root), a far lateral disc herniation will affect the L4 nerve root (i.e. exiting root) as it exits the L4/5 foramen. That means that the standard midline approach will not allow easy lateral access. Therefore, the Wiltse paraspinal approach is ideal, which preserves segment stability by avoiding injury to the lamina and facet joints. The potential complication to know from the Wiltse approach is potential dorsal root ganglia injury resulting in dysesthesias.

O'Hara and Marshall present their results on 20 patients that had a far lateral disc prolapse and underwent their muscle-splitting, intertransverse approach. They report that from six months to four years, 12 patients had excellent results with no residual pain, six had good results with mild discomfort and no functional impairment, and two had poor results. They recommend the use of a muscle-splitting intertransverse approach to far lateral herniation of the disc, using the posterior primary ramus as the key to safe dissection.

Wiltse and Spencer provide a review of new uses and refinements of the paraspinal approach to the lumbar spine (1988) based on their original description of the approach from 1968. They report their approach differs from the approach described by Melvin Watkins in 1953 in that it is a longitudinal separation of the sacrospinalis group between the multifidus and longissimus, and not between the lateral border of the entire sacrospinalis group and quadratus lumborum. They further discuss its use for removing a far lateral disc, inserting pedicle screws, and decompressing the opposite side from inside the vertebral canal.

Figure A demonstrates a lateral lumbar radiograph with multilevel degenerative disc disease. However, this patient is experiencing minimal lower back pain, and therefore surgical intervention should be guided to address the patient's symptoms at hand (i.e. radiculopathy). Figure B is an axial MRI image demonstrating a far lateral disc herniation at L4/5 on the right.

Incorrect Answers:
Answers 1, 4, and 5: In general, a fusion-based procedure is most appropriate in the setting of spondylolisthesis, or when significant facet arthropathy or degenerative disc disease (DDD) is present (lumbar disc arthroplasty may also be considered in the setting of DDD). Lumbar interbody fusion (LIF) is divided into several types based on approach (ALIF, TLIF, LLIF, etc.). Nonetheless, this patient has no evidence of spondylolisthesis, making isolated decompression the most appropriate treatment option.
Answer 3: A posterior midline hemilaminectomy with discectomy would be appropriate for a central or posterolateral/paracentral disc herniation.