Intraoperative Myelography in Transpsoas Lateral Lumbar Interbody Fusion for Degenerative Lumbar Spinal Stenosis: A Preliminary Prospective Study

Abstract

Aim To investigate the feasibility and effectiveness of intraoperative myelography in determining adequacy of indirect spinal canal decompression during transpsoas lateral lumbar interbody fusion (LLIF). Methods Seven patients diagnosed with degenerative lumbar spinal stenosis (DLSS) were prospectively included to this study. All patients underwent LLIF and subsequently received intraoperative myelography to determine the effect of indirect spinal canal decompression, which was visualized in both anterior-posterior and lateral images. Those patients with insufficient indirect canal decompression were further resolved by microendoscopic canal decompression (MECD). Radiological parameters, including stenosis ratio and dural sac area of operated levels, were measured and compared before and after operation. Besides, all patients were followed up for at least one year using visual analogue scale (VAS) for back and leg, Japanese Orthopaedic Association score (JOA), and Oswestry disability index (ODI). Results Seven patients with 8 operated levels underwent LLIF safely and demonstrated significant symptom relief postoperatively. Five operated levels showed adequate indirect canal decompression intraoperatively, while the remaining three levels did not achieve the adequacy, and their residual stenosis was resolved following MECD. Radiological parameters were improved statistically when compared with preoperation (P < 0.05). Furthermore, neurological symptoms of all patients were also improved significantly (P < 0.05), shown by improved VAS (back and leg), JOA, and ODI at both two-week and one-year follow-up. Conclusions Intraoperative myelography during LLIF is able to assess adequacy of indirect canal decompression for DLSS, thus promising favorable clinical outcomes.

Lateral Lumbar Interbody Fusion: What is the Evidence of Indirect Neural Decompression? A Systematic Review of the Literature

“…Nine papers reported variations in both DH (X) and FA (Y) [9,20,23,27,37,40,43,55,59]. The outcome of the corresponding regression The canal area (CA) was evaluated by ten authors [9,14,19,20,37,40,43,55,59,60]. The mean CA increase was estimated at 36.4 ± 26.3 mm 2 (95% CI, 18.1-54.7; mean increase, 29.3%).…”

“…A total of 42 articles were eventually included in our systematic review [1, 3–5, 7–9, 11, 13–15, 17, 19–25, 27–30, 32, 33, 36–41, 43–46, 49, 51, 52, 55, 56, 59, 60]. Two studies were level II evidence [19, 52], seven were level III evidence [11, 24, 32, 46, 49, 56, 59], and the remaining were level IV evidence (Fig.…”

“…Twenty authors reported a mean improvement of back and leg pain with VAS score reduction of 4.1 ± 2.5 (95% CI, 3.6–4.6) and 3.9 ± 2.2 (95% CI, 3.4–4.4), respectively [3–5, 13–15, 20–22, 27–30, 33, 35, 37, 38, 45, 56, 60]. Table 3 provides a summary of the clinical outcomes reported by the included studies.…”

“…The canal area (CA) was evaluated by ten authors [9, 14, 19, 20, 37, 40, 43, 55, 59, 60]. The mean CA increase was estimated at 36.4 ± 26.3 mm 2 (95% CI, 18.1–54.7; mean increase, 29.3%).…”

“…Castellvi et al [9] detected a 17% improvement in CA at 1-year follow-up. The evaluation of central canal area was performed with CT scan in three studies (pre-operative mean CA, 122.8 ± 52.5 mm 2 ; post-operative mean CA, 174.2 ± 42.9 mm 2 ) [9, 20, 60] and MRI in four studies (pre-operative mean CA, 124.9 ± 44.6 mm 2 ; post-operative mean CA, 171.8 ± 48.7 mm 2 ) [40, 43, 59], and three used both imaging techniques (pre-operative mean CA, 117.7 ± 16.4 mm 2 ; post-operative mean CA 136.6 ± 17.2 mm 2 ) [36, 52, 55]. The authors who performed measurements with both modalities did not specify the method to extrapolate the declared CA.…”