Five-year clinical outcomes with endoscopic transforaminal outside-in foraminoplasty techniques for symptomatic degenerative conditions of the lumbar spine

Abstract

Background: Lumbar foraminal stenosis in the extraforaminal zone is best directly visualized with the outside-in transforaminal endoscopic technique. Stenosis in that area is often missed with traditional translaminar surgery. The authors analyzed the long-term 5-year clinical results, reoperation rates, and unintended after care with the outside-in endoscopic transforaminal foraminoplasty for symptoms from lumbar foraminal stenosis to better establish clinical indications and prognosticators of favorable outcomes.

Methods: Long-term 5-year Macnab outcomes, visual analog scale (VAS) scores, complications, and unintended aftercare were analyzed in a series of 90 patients treated with the transforaminal outside-in selective endoscopic discectomy (SED™) with foraminoplasty for foraminal and lateral recess stenosis.

Results: At minimum 5-year follow-up, excellent results according to the Macnab criteria were obtained in 61 (67.8%) patients, good in 23 (25.6%), fair in 6 (6.7%), respectively. The mean preoperative VAS 7.55. The mean postoperative VAS was 2.87 and at last follow-up 2.53. Both postoperative VAS and last follow-up VAS were statistically reduced at a significance level of P<0.0001. Postoperative dysesthesia occurred in 8 patients (8.9%). While most of the 32 follow-up surgeries following SED™ were additional endoscopic decompressions and rhizotomies (24/32; 75%) were non-fusion procedures, only 8 of the whole study series of 90 patients (8.9%) underwent fusion at the index SED™ level within the minimum 5-year follow-up period. One patient opted for an open laminectomy (1.1%).

Conclusions: Patients with symptomatic foraminal stenosis may be treated successfully in a staged manner with outside-in transforaminal endoscopic decompression while maintaining favorable long-term outcomes without the excessive need for fusion in the vast majority of patients. The reoperation fusion rate at 5-year follow-up was approximately 3 times lower when compared to recently reported reoperation rates following traditional translaminar decompression/fusion.

Keywords: Percutaneous transforaminal decompression; foraminal foraminoplasty; foraminal stenosis; lumbar spine; spinal stenosis.

Figure 1

Age distribution of patients with 5-year follow up after endoscopic transforaminal foraminoplasty for foraminal stenosis with the superimposed expected normal distribution (black line). Patient’s age ranged from 19 to 84 years of age and averaged 59.16 years.