Abstract
Introduction
The surgical treatment of disc disease L5- S1 is considerably controversial and a source of debate and applied research. TheAxiaLif® Technique (Trans1, Wilmington, NC) involves the fusion of the anterior segment L5 -S1 using a minimally invasive pre-sacral approach. It consists of a short parasacral distal incision, the cut of the sacro-coccygeal ligament and the gradual detachment of the mesorectum from the front wall of the sacrum. Through a dedicated minimally invasive system S1 is reached and a simple guide set enable the surgeon to perform discectomy and prepare the disc space for the graft filling and house the screw. In selected cases is possible to perform a circumferential fusion through posterior fixation with percutaneously inserted systems such as either transarticular screws or pedicle screws/rods.
Materials and Methods
From 2009 to 2013 a total of 52 patients have been treated with L5-S1 interbody fusion through AxiaLif® Technique (Trans1, Wilmington, NC). The patients cohort is subdivided in 12 males and 40 females, mean age 46.3 years (range 21–67). Diagnosis included L5 isthmic spondylolisthesis low-grade dysplasia, primary degenerative disc disease, disc disease secondary to previous discectomy. Exclusion criteria included previous abdominal surgery and anatomical anomalies of the sacrum (curvature of the sacrum did not allow an ideal passage of the probe). 43 patients have been followed for at least 2 years. Baseline imaging included plain and dynamic radiographs and MRI. Fusion assessment was based on plain radiographs and Brantigan fusion criteria at 1, 6, 12 and 24 months after surgery. In addition, all patients completed the VAS and ODI at baseline through last follow-up.
Results
The clinical results showed a good resolution of painful symptoms and a good recovery of the quality of life. VAS back demonstrated an average reduction over baseline of 50%, 57%, 71%, 77% at 3 month, 6 month, 12 month and 24 months, respectively (p < 0.001). ODI demonstrated an average reduction over baseline of 38%, 51%, 67%, and 72% at the same time points (p < 0.001). There were 27 subjects with 36 month data that demonstrated an average 80% reduction in pain and a sustained reduction in ODI by 73%. Complete fusion was demonstrated in 65% of cases, 30% partial fusion and 5% in the absence of bony bridges visible radiographically. Two major complications: 1 retroperitoneal hematoma, requiring surgical evacuation and 1 spondylodiscitis due to Staphylococcus aureus, resulting in the removal of the axial screw and targeted antibiotic therapy, with complete recovery at the end. One minor complication, a superficial infection of the surgical wound, which resolved with antibiotic therapy.
Conclusions
The surgical treatment of disc disease at L5-S1 with minimally invasive technique Axialif has led to good clinical outcomes. In our opinion, this method can be a good alternative to more aggressive approaches such as either the anterior retroperitoneal one or the posterior one. The first option actually could led to higher risk of complications and the frequent need of the vascular surgeon assistance. The second option is destructive for the lumbar muscles and requires a longer recovery period. In the case series presented, the low rate of complications, the high value of patient satisfaction and the efficacy of radiographic fusion justify the choice of this type of L5S1 arthrodesis. Moreover, shorter hospitalization and faster functional recovery are adding factors to choice this technique in selected cases.