Topping-off surgery vs posterior lumbar interbody fusion for degenerative lumbar disease: a comparative study of clinical efficacy and adjacent segment degeneration

Abstract

Background: Studies have shown that adjacent segment degeneration (ASD) is a common complication after posterior lumbar interbody fusion (PLIF), even a second surgery is required for some patients. It remains unclear whether the non-fusion surgery can relieve ASD. Therefore, this study aims to investigate the clinical outcomes of Topping-off surgery (fusion combined with Coflex) and PLIF for degenerative lumbar disease (DLD) and the efficacy on preventing ASD.

Method: A retrospective analysis was performed on the clinical data of 99 patients with DLD from January 2011 to December 2014, who were performed by Topping-off surgery (L4-5 PLIF + L3-4 Coflex, n = 45) or PLIF (L3-5 PLIF, n = 54). All patients included in the analysis had a minimum of 3 years of follow-up. Clinical data were used to assess the clinical efficacy, and radiographic parameters were measured for evaluation of the incidence of ASD.

Results: The mean ages of Topping-off group and PLIF group were 53.5 and 65.7 years old, respectively (P < 0.05). The surgical time, intraoperative blood loss, Oswestry disability index (ODI), and visual analog scale (VAS) were significantly different between the two groups (P < 0.05). Intervertebral mobility (L2-L3) of the Topping-off group was not changed significantly at 3 years after surgery than before (P > 0.05), while that of PLIF group was increased considerably (P < 0.05). As to intergroup comparison, intervertebral mobility (L2-L3) of Topping-off group was superior to those of the PLIF group (P < 0.05). Surprisingly, there was no significant difference in the general adjacent segment mobility (GASM) at L2-4 of the Topping-off group and intervertebral mobility (L2-L3) of PLIF group at 3 years after surgery (P > 0.05). Lumbar MRI at three post-operative years indicated that the modified Pfirrman grading of disc (L2-L3) in the Topping-off group was much better than that of the PLIF group (P < 0.05).

Conclusion: This study showed that Topping-off surgery had the benefits of less invasiveness, less bleeding, and comparable clinical efficacy as PLIF for DLD. The segment with Coflex insertion undertook part of the mobility and stress in the proximal lumbar spine, which is conducive to alleviating ASD.

Keywords: Adjacent segment degeneration (ASD); Clinical efficacy; Coflex; Degenerative lumbar disease (DLD); Posterior lumbar interbody fusion (PLIF); Topping-off.

Fig. 1

Lateral flexion and extension lumbar X-ray showing radiological indices studied. Adjacent intervertebral mobility (L2–L3) = extension angle (a)–flexion angle (a’). Intervertebral mobility (L3–4) with Coflex insertion = extension angle (b)–flexion angle (b’). General adjacent segment mobility (GASM) at L2–4 = extension angle (c)–flexion angle (c’)

Fig. 2

A 44-year-old, female, patient complained of lower back pain and pain in the left lower limb for 8 years, with aggravation for 6 months. This patient had spinal canal stenosis at L3–L5 and received Topping-off surgery. a–d X-ray for the lumbar spine in the anteroposterior/lateral and flexion/extension views before surgery; intervertebral mobility 3.9° at L2–L3 and 4.2° at L3–L4. e–g Lumbar MRI scan before surgery indicated spinal canal stenosis at L3–L5, with modified Pfirrmann grade of disc 4 at L2–L3. h–k X-ray for the lumbar spine in the anteroposterior/lateral and flexion/extension views at 36 months after surgery. There was no significant change in the intervertebral mobility at L2–L3, which was 4.2° after surgery; the intervertebral mobility at L3–L4 was decreased to 2.9° after surgery. l MRI scan at 36 months after surgery indicated that the modified Pfirrmann grade of disc was still 4 at L2–L3

Fig. 3

A 66-year-old, male, patient complained of lower back pain and pain in bilateral lower limbs for 2 years and aggravation for 7 months. There was spinal canal stenosis at L3–L5, and the patient received PLIF at L3–L5. a–d X-ray for the lumbar spine in the anteroposterior/lateral and flexion/extension views before surgery; intervertebral mobility 4.3° at L2-L3. e–g Lumbar MRI scan before surgery indicated spinal canal stenosis at L3–L4 and L4–L5, with modified Pfirrmann grade of disc 3 at L2–L3; h–k X-ray for the lumbar spine in the anteroposterior/lateral and flexion/extension views at 36 months after surgery. The intervertebral mobility at L2–L3 was increased significantly to 7.3° after surgery. l MRI scan at 36 months after surgery indicated that the modified Pfirrmann grade of disc was increased to grade 4 at L2–L3