Analysis of the causes and clinical characteristics of lumbar re-operative surgery for patients with high intervertebral space height

English Keywords:Lumbar degeneration  High intervertebral space height  Interbody fusion  Adjacent segment disease  Lumbar sagittal alignment

English Abstract:

  【Abstract】 Objectives: To analyze the causes and clinical characteristics of re-operative surgery of patients with high lumbar intervertebral space height(hIVSH), and to clarify the effect of hIVSH restoration on clinical results and lumbar-pelvic alignment. Methods: Clinical data from 42 patients who underwent re-operative surgery with high intervertebral cages(≥14mm) placement in our hospital from January 2014 to November 2024 were collected. The patients included 23 males and 19 females, aged 41-85 years old(59.5±8.6 years old). 23 patients undergone re-operation at the original segment were included in the original segment re-operation group(group A); 19 patients who were re-operated due to adjacent segment degeneration(ASD) were included in the adjacent segment re-operation group(group B). The time interval between re-operation and the previous surgery, preoperative and final follow-up visual analogue scale(VAS) score and Japanese Orthopaedic Association(JOA) score were collected and analyzed. In group B, the intervertebral space height(IVSH), fusion area of the previous fusion segment, range of motion of the previous surgical segment, Pfirrmann grades of the intervertebral disc at the re-operative segment, pelvic inclination(PI), pelvic tilt(PT), and lumbar lordosis(LL) were measured. Group B was further divided into the hIVSH group(group B1, full restoration of IVSH) and the low IVSH group(group B2, incomplete restoration of IVSH) based on whether the IVSH was fully restored in the previous fusion segment. The above parameters were thereby compared. Results: The re-operations were all completed successfully in 42 cases. Herein, 36 cases(85.7%) were the second surgeries, 5 cases(11.9%) were the third surgeries, and 1 case(2.4%) was the fourth surgery. A total of 54 lower lumbar segments were re-operated, including 17 at L3/4(31.5%), 30 at L4/5(55.6%), and 7 at L5/S1(12.9%). The time interval between surgeries in group B1 was 9.55±3.47 years, which was longer than that in group B2(4.55±3.62 years) and group A(3.29±5.36 years). The follow-up period was 0.25-11 years(6.24±2.96 years). At the final follow-up, VAS and JOA scores were significantly improved in groups A, B1, and B2 compared with preoperative scores(P<0.05); Group B2 was higher in VAS score(P<0.05) and lower in JOA score(P<0.01) than group A before operation, and was lower in JOA score than group A at final follow-up(P<0.05). B1 group was lower in JOA score than group A before operation(P<0.02). There was no significant difference in fusion area in previous operated segment between groups B1 and B2(1.26±0.30cm2 vs 1.13±0.15cm2, P>0.05) or range of motion(5.22°±1.97° vs 3.93°±1.79°, P>0.05). However, the Pfirrmann grades of intervertebral disc degeneration was better in group B1 than group B2. There was no significant difference in PI, PT, or LL between groups B1 and B2 preoperatively and postoperatively(P>0.05). Nonetheless, preoperative LL in group B1(46.57°±5.61°) was significantly greater than group B2(40.08°±6.5°)(P<0.05). Conclusions: Complete restoration of hIVSH does not significantly affect interbody fusion or segmental stability. However, it helps to improve LL which results in better Pfirrmann grade of adjacent segment.