SpineUniverse Case Study Library

L4-L5 Foraminal Spinal Stenosis in an Elderly Male


The patient is a 77-year-old male who underwent laminectomy at L4-L5 and L5-S1, which was complicated by a cerebrospinal (CFS) fluid leak. The laminectomy was performed at another center. He presents with persistent right lumbar radiculopathy.

His past medical history includes asthma, prior right knee replacement, and hypothyroidism.


  • Positive straight leg raise on right
  • Motor function: full bilateral lower extremities
  • Reflexes: +1 at bilateral knees and ankles

Pre-treatment Imaging

Figure 1. The sagittal lumbar MRI demonstrates multilevel degenerative disc disease (DDD). Image courtesy of Joshua M. Ammerman, MD, and SpineUniverse.com.

Figure 2. Shows right-sided L4-L5 severe foraminal stenosis and DDD. Image courtesy of Joshua M. Ammerman, MD, and SpineUniverse.com.

Prior Treatment

Physical therapy and repeated spinal injections have failed to resolve the patient's right lumbar radicular symptoms.

Suggest Treatment

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Selected Treatment

L4-L5 oblique lumbar interbody fusion with pedicle screws in the lateral position.

Surgeons' Treatment Rationale

  • Primary pathology is foraminal stenosis; therefore restoration of foraminal height is critical, which is best achieved through placement of a large interbody graft
  • Desire to avoid working through the previous scarred posterior surgical field with prior CSF leak
  • Avoidance of dissection through the psoas muscle at L4-L5 with the potential risk to the femoral nerve and lumbar plexus
  • Screw placement in the lateral position saves operative time as it avoids the need to reposition the patient from lateral to prone

Intra-operative Photos

The photos (below) demonstrate pedicle screw placement in the lateral position.

Image courtesy of Joshua M. Ammerman, MD, and SpineUniverse.com.

Image courtesy of Joshua M. Ammerman, MD, and SpineUniverse.com.

Image courtesy of Joshua M. Ammerman, MD, and SpineUniverse.com.

Post-operative X-rays

Image courtesy of Joshua M. Ammerman, MD, and SpineUniverse.com.

Image courtesy of Joshua M. Ammerman, MD, and SpineUniverse.com.


The patient experienced immediate resolution of leg pain. He was discharged on post-operative day one.

Discussion Points

OLIF (Oblique Lumbar Interbody Fusion)

1. Creates a surgical corridor anterior to the psoas muscle, avoiding dissection of the muscle and mitigates potential trauma to the femoral nerve and lumbar plexus

2. Also, rotates the axis of approach anterior to the illiac crest facilitating access to L4-L5

3. Given the large graft size that can be placed via OLIF, significant disc height restoration and, therefore, foraminal expansion can be achieved

4. Graft placement on the cortical rims of the vertebrae helps to resist subsidence

5. Given the large graft footprint, in our experience, unilateral pedicle screw fixation appears adequate in single-level procedures

Peer Discussion

The surgeons in this case present a novel solution to a complicated clinical case—how to revise a failed decompression in the face of a previous CSF leak and a severely degenerative lumbar level. No doubt this patient needed a lumbar fusion and a revision decompression; the question is how?

The authors rightfully pointed out that their technique avoids a lateral approach through the psoas and its comorbidities while at the same time achieving the same result of an indirect decompression, restoration of foraminal height and stabilizing the segment. This solution avoids performing a revision decompression through an area that experienced a CSF leak and also avoids having to perform a posterolateral fusion and instrumentation with its associated blood loss and increased operative time.

The main concern of this approach is whether or not unilateral screws are able to create a construct that is stable enough. The authors point to their experience to give a positive answer to this question. The authors additionally claim that the large graft size (height and footprint) used can give stability to the anterior column therefore, making bilateral pedicle screws redundant.

In 2012, Xue et al1 came to a similar conclusion pointing out the advantages of unilateral pedicle screws in a TLIF approach. These advantages include: decreased operative time, diminished blood loss, decreased implant cost while noting no decrease in fusion rates or any increase in complication rates.

Overall, the author's solution to this difficult clinical case is creative, thoughtful and provides a template for other surgeons to emulate in treating similar difficult cases.

1. Xue H, Tu Y, Cai M. Comparison of unilateral versus bilateral instrumented transforaminal lumbar interbody fusion in degenerative lumbar diseases. Spine J. 2012;12:209-15.

Community Case Discussion (1 comment)

SpineUniverse invites spine professionals to share their thoughts on this case.

I congratulate the authors for solving this difficult case expertly.
For me, the OLIF procedure is just a modified version of mini-ALIF. It use a smaller incision, has more limited view, requires tactile/blind dissection, and meticulous work and expertise to avoid severe complications. Also, it is technology-dependent.
For those reasons, I guess this procedure will never be popularized. I would like to hear other surgeons' thoughts on this opinion.


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