Superior Articular Facet Interbody Reconstruction (SAFIR)
A novel posterior lumbar interbody fusion approach
The patient is a 74-year-old female who presents with 9 months of back and right greater than left leg pain. Four years ago, she underwent anterior lumbar interbody fusion (ALIF) with pedicle screws at L4-S1. Her Oswestry Disability Index (ODI) is 20.
Her past medical history includes borderline diabetes, obesity, and hypertension. She is a nonsmoker.
- Positive right femoral stretch
- Trace right quadriceps weakness
- Diminished right knee reflex
Lateral herniated nucleus pulposus (HNP) at L3-L4 with disc space collapse; prior L4-S1 ALIF. (Figures 1-4 below)
A trial of organized physical therapy and selective nerve root injections were not effective.
Lateral HNP at L3-L4 with disc space collapse
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Right L3-L4 superior articular facet interbody fusion (SAFIR).
Inferior articular process (IAP) and superior articular process (SAP). (Figure 5, below)
Disc space and L3 nerve root. (Figures 7-8, below)
Initial height restoration with paddle distractor and maintained with contralateral percutaneous screws; prior to LUNA (Benvenue Medical, Inc., Santa Clara, CA) insertion. (Figures 9-10, below)
Bone graft in LUNA. (Figure 11, below)
- Surgical time: 110-minutes
- Hospital length of stay: 40-hours
- Estimated blood loss: 45cc
The patient experienced immediate resolution of leg pain (bilaterally), and back pain was much improved by postoperative day 1.
- ODI preoperatively: 20
- ODI at 12 weeks postop: 0
CT at 12 Weeks Postoperative
Benefits of a "SAFIR" procedure:
- Avoids intrusion into the spinal canal
- Permits direct decompression of the ipsilateral neural foramen
- Indirect decompression of the central canal and contralateral neural forament via height restoration
- Restoration of lordosis and disc height
- Familiar anatomy
- No access surgeon needed
- Enabled by the use of a unique 3D expanding interbody device (LUNA®, Benvenue Medical, Inc., Santa Clara, CA)
Doctors Ammerman and Wind illustrate a problem that most experienced spine surgeons experience with monotonous regularity—adjacent segment failure after prior fusion. The authors are to be congratulated on an excellent surgical, radiological and clinical outcome with their targeted MIS approach.
There are many ways to ‘skin this cat’, which includes various posterior or lateral approaches; perhaps anterior or combined with or without interbody fusion, open, mini-open or MIS. No result is better than the other in a definitive fashion. The surgeons in this case report have shown a high level of skill which, in their hands has shown an excellent outcome. Every surgeon will need to find their level of comfort in deciding what works for them.