Modified minimally invasive-transforaminal lumbar interbody fusion under microscopic view to achieve bilateral decompression and fusion through a single approach to treat developmental lumbar spinal stenosis

Three-dimensional High-definition Exoscope in Minimally Invasive Transforaminal Lumbar Interbody Fusion: A Retrospective Cohort Study

OBJECTIVES

The operative microscope (OM) has revolutionized the field of modern spine surgery, however, it remains limited by several drawbacks. Recently, the exoscope (EX) system has been designed to assistant spine surgery. It provides a three-dimensional (3D) high-definition (HD) operative experience and becomes an alternative to the OM. The aim of the study was to evaluate the clinical outcomes, advantages and limitations of EX-assisted minimally invasive transforaminal lumbar interbody fusion (EMIS-TLIF) and OM-assisted MIS-TLIF (OMIS-TLIF).

METHODS

The clinical outcomes were assessed in 47 patients with lumbar degenerative diseases (LDD) who underwent MIS-TLIF assisted with the OM or EX between January 2019 and September 2020. A total of 22 were treated with EMIS-TLIF, and 25 received OMIS-TLIF. Perioperative parameters (including sex, age, number of fusion levels and body mass index), perioperative parameters (operation time, intraoperative blood loss, postoperative drainage, postoperative hospitalization stay, and duration of follow-up), visual analogue scale (VAS) of back pain, VAS of leg pain, Oswestry disability index (ODI) scores and clinical outcomes were assessed and compared. Image quality, handling of equipment, ergonomics, 3D glasses and educational usefulness were scored according to a questionnaire.

RESULTS

Operation time in the OMIS-TLIF group (121.92 ± 16.92 min) was significantly increased compared with that in the EMIS-TLIF group (111.00 ± 19.87 min) (P < 0.05). The VAS of the back pain and ODI scores in the EMIS-TLIF group were significantly lower compared with the OMIS-TLIF group at 1 week postoperatively (P < 0.05). The good-excellent outcomes rate was 90.91% in the EMIS-TLIF group and 88.00% in the OMIS-TLIF group, and there was no significant difference. A total of 44 visits completed the questionnaire. The results of the questionnaire showed that the EX has exhibited advantages regarding handing of equipment, ergonomics and educational usefulness, and comparable image quality as compared with the OM, however, operating surgeons complained uncomfortable sensation when wearing 3D glasses.

CONCLUSIONS

The EMIS-TLIF was a safe and effective procedure in the management of LDD as compared with the OMIS-LIF. Meanwhile, EMIS-TLIF might resulted in a short operation time.

Postlaminectomy lumbopelvic sagittal changes in patients with developmental lumbar spinal stenosis grouped into Roussouly lumbopelvic sagittal profiles: 2- to 10-year prospective follow-up

OBJECTIVE

Roussouly lumbopelvic sagittal profiles are associated with distinct pathologies or distinct natural histories and prognoses. The associations between developmental lumbar spinal stenosis (DLSS) and native lumbopelvic sagittal profiles are unknown. Moreover, the relative effects of multilevel decompression on lumbar sagittal alignment, geometrical parameters of the pelvis, and compensatory mechanisms for each of the Roussouly subtypes are unknown. This study aimed to explore the association between DLSS and native lumbar lordosis (LL) subtypes. It also attempts to understand the natural history of postlaminectomy lumbopelvic sagittal changes and compensatory mechanisms for each of the Roussouly subtypes and to define the critical lumbar segment or specific lordosis arc that is recruited after relief of the stenosis effect.

METHODS

A total of 418 patients with multilevel DLSS were grouped into various Roussouly subtypes, and lumbopelvic sagittal parameters were prospectively compared at follow-up intervals of preoperative to < 2 years, 2 to < 5 years, and 5 to ≥ 10 years after laminectomy. The variables analyzed included LL, upper lordosis arc from L1 to L4, lower lordosis arc from L4 to S1, and segmental lordosis from L1 to S1. Pelvic parameters included pelvic incidence, sacral slope, pelvic tilt, and pelvic incidence minus LL values.

RESULTS

Of the 329 patients who were followed up throughout this study, 33.7% had Roussouly type 1 native lordosis, whereas the incidence rates of types 2, 3, and 4 were 33.4%, 21.9%, and 10.9%, respectively. LL was not reduced in any of the Roussouly subtypes after multilevel decompressions. Instead, LL increased by 4.5° (SD 11.9°-from 27.3° [SD 11.5°] to 31.8° [SD 9.8°]) in Roussouly type 1 and by 3.1° (SD 11.6°-from 41.3° [SD 9.5°] to 44.4° [SD = 9.7°]) in Roussouly type 2. The other Roussouly types showed no significant changes. Pelvic tilt decreased significantly-by 2.8°, whereas sacral slope increased significantly-by 2.9° in Roussouly type 1 and by 1.7° in Roussouly type 2. The critical lumbar segment that recruits LL differs between Roussouly subtypes. Increments and changes were sustained until the final follow-up.

CONCLUSIONS

The study findings are important in predicting patient prognosis, LL evolution, and the need for prophylactic or corrective deformity surgery. Multilevel involvement in DLSS and the high prevalence of Roussouly types 1 and 2 suggest that spinal canal dimensions are closely linked to the developmental evolution of LL.