Factors affecting approach selection for minimally invasive versus open surgery in the treatment of adult spinal deformity: analysis of a prospective, nonrandomized multicenter study

Treatment Strategies in the Osteoporotic Spine

This article reviews the appropriate assessment and management of osteoporotic compression fractures and discusses the implications of osteoporosis on initial patient evaluation, medical optimization for surgery, selection of instrumentation, and surgical technique. Adverse outcomes associated with osteoporosis are discussed. Failure to appropriately evaluate, optimize, and treat spine patients with osteoporotic bone can lead to disastrous complications. Weakened bone can lead to implant failure through cage subsidence and screw pullout, as well as, peri-implant fractures, failure of deformity correction, and proximal kyphosis. These risks must be taken into account when considering operative interventions in these patients.

Anterior Column Realignment Through Open Pre-posterior Release-Anterior-Posterior Fusion Versus Hybrid Minimally Invasive-Anterior-Posterior Fusion for Dynamic Sagittal Imbalance of the Spine

STUDY DESIGN

Retrospective comparative study.

OBJECTIVES

To investigate the clinical and radiological outcomes after anterior column realignment (ACR) through pre-posterior release-anterior-posterior surgery (PAP) and minimally invasive surgery -lateral lumbar interbody fusion (MIS-LLIF) using hybrid anterior-posterior surgery (AP).

METHODS

A total of 91 patients who underwent ACR with long fusions from T10 vertebra to the sacropelvis with a follow-up period of at least 2 years after corrective surgery for adult spinal deformity were included and divided into two groups by surgical method: AP and PAP. AP was performed in 26 and PAP in 65 patients. Clinical outcomes and radiological parameters were investigated and compared. A further comparison was conducted after propensity score matching between the groups.

RESULTS

The more increase of LL and decrease of PI-LL mismatch were observed in the PAP group than in the AP group postoperatively. After propensity score matching, total operation time and intraoperative bleeding were greater, and intensive care unit care and rod fracture were more frequent in the PAP group than in the AP group with statistical significance. Reoperation rate was higher in PAP (29.2%) than in AP (16.7%) without statistical significance.

CONCLUSIONS

PAP provides a more powerful correction for severe sagittal malalignment than AP procedures. AP results in less intraoperative bleeding, operation time, and postoperative complications. Therefore, this study does not suggest that one treatment is superior to the other.

LEVEL OF EVIDENCE

III.

Less correction with minimally invasive surgery for adolescent idiopathic scoliosis compared to open surgical correction

Purpose

In this study, we investigated the relationship between the results of thoracic curve correction using minimally invasive surgeries in 35 patients and open surgical correction in 47 patients with adolescent idiopathic scoliosis.

Methods

The correlations between the Cobb's angle of the primary and postoperative curves, angle of thoracic kyphosis and lumbar lordosis, correction percentage, derotation values, estimated blood loss, duration of surgery, and period of hospitalization after surgery were assessed by calculating the mean and standard deviation. Calculation and comparison were performed using Pearson correlation.

Results

The Cobb's angle correction ranged from 53.4° ± 11.8° to 6.7° ± 5.2° (p < 0.001) in the open surgical correction group and from 51.2° ± 11.4° to 11.7° ± 5.8° (p < 0.001) in the minimally invasive surgery group before and after surgery, respectively. The percentage of curvature correction was 88.2% ± 8.0% and 77.7% ± 10.7% (p < 0.001) in the open surgical correction and minimally invasive surgery groups, respectively. The estimated blood loss was higher in the open surgical correction group than in the minimally invasive surgery group (208.7 ± 113.4 vs 564.3 ± 242.7 mL). Axial rotation was changed from 29.1°± 7.5 to 17.1°± 6.8 (p < 0.001) in the open surgical correction group and from 28.9°± 7.8 to 19.4°± 6.4 (p < 0.001) in the minimally invasive surgery group. The duration of surgery was shorter in the open surgical correction group than in the minimally invasive surgery group (266.6 ± 64.3 vs 346.2 ± 70.5 min). A positive correlation between time of operation and Cobb's angle correction (in °) in open surgical correction (r = 0.37) and minimally invasive surgery (r = 0.43) was found.

Conclusion

The open surgical correction procedures were more effective than minimally invasive surgery in correcting the spinal curve. The increase in the duration of open surgical correction increases the estimated blood loss, but it also more significantly improves the correction of Cobb's angle.

Level of evidence

III.

Less correction with minimally invasive surgery for adolescent idiopathic scoliosis compared to open surgical correction

Purpose:

In this study, we investigated the relationship between the results of thoracic curve correction using minimally invasive surgeries in 35 patients and open surgical correction in 47 patients with adolescent idiopathic scoliosis.

Methods:

The correlations between the Cobb’s angle of the primary and postoperative curves, angle of thoracic kyphosis and lumbar lordosis, correction percentage, derotation values, estimated blood loss, duration of surgery, and period of hospitalization after surgery were assessed by calculating the mean and standard deviation. Calculation and comparison were performed using Pearson correlation.

Results:

The Cobb’s angle correction ranged from 53.4° ± 11.8° to 6.7° ± 5.2° ( p < 0.001) in the open surgical correction group and from 51.2° ± 11.4° to 11.7° ± 5.8° ( p < 0.001) in the minimally invasive surgery group before and after surgery, respectively. The percentage of curvature correction was 88.2% ± 8.0% and 77.7% ± 10.7% ( p < 0.001) in the open surgical correction and minimally invasive surgery groups, respectively. The estimated blood loss was higher in the open surgical correction group than in the minimally invasive surgery group (208.7 ± 113.4 vs 564.3 ± 242.7 mL). Axial rotation was changed from 29.1°± 7.5 to 17.1°± 6.8 ( p < 0.001) in the open surgical correction group and from 28.9°± 7.8 to 19.4°± 6.4 ( p < 0.001) in the minimally invasive surgery group. The duration of surgery was shorter in the open surgical correction group than in the minimally invasive surgery group (266.6 ± 64.3 vs 346.2 ± 70.5 min). A positive correlation between time of operation and Cobb’s angle correction (in °) in open surgical correction ( r = 0.37) and minimally invasive surgery ( r = 0.43) was found.

Conclusion:

The open surgical correction procedures were more effective than minimally invasive surgery in correcting the spinal curve. The increase in the duration of open surgical correction increases the estimated blood loss, but it also more significantly improves the correction of Cobb’s angle.

Level of evidence:

III.

Management of severe adult spinal deformity with circumferential minimally invasive surgical strategies without posterior column osteotomies: a 13-year experience

OBJECTIVE

To evaluate the mid- to long-term clinical outcomes of circumferential minimally invasive surgery (CMIS) without posterior column osteotomies for severe adult spine deformity (ASD) correction.

METHODS

All patients with a minimum of 2-year follow-up undergoing staged CMIS correction of ASD from January 2007 to July 2018 were identified. All included patients had fusion of 3 or more interbody levels that spanned the L5-S1 junction. Only patients with severe deformity, Coronal Cobb > 50° or at least one SRS-Schwab ++ sagittal modifier (SVA > 95 mm, or PI-LL > 20, or PT > 30) were included. All complications were noted.

RESULT

136 patients met inclusion criteria; mean age of patients was 63.6 years (21-85, SD 13.7). The mean follow-up was 82.8 months (24-159, SD 36.6). The mean number of levels fused was 7 (3-16, SD 3). A total of 40 (29.4%) major complications were noted at final follow-ups: 2 (1.4%) intra-operative, 12 (8.9%) peri-operative (≤ 6 weeks from index), 26 (19.1%) post-operative (> 6 weeks from index). There was a total of 53 (40.0%) minor complications. Seven (5.1%) patients who developed radiographic proximal junctional kyphosis. Three patients (2.2%) developed proximal junctional failure. There were 8 (5.9%) cases of pseudarthrosis. Five of these occurred in patients undergoing AxiaLIF. All patients experienced improvements in patient-perceived outcomes (VAS, TIS, ODI, and SRS-22) and radiographic parameters at last follow-up when compared to pre-op (p < 0.05).

CONCLUSION

Rates of complications with CMIS correction of severe ASD are lower than published rates of complications seen with open ASD correction. Specifically, the incidence of catastrophic complications is lower. Furthermore, CMIS is associated with significant improvements in clinical and functional outcomes, low rates of pseudarthrosis and proximal junctional kyphosis. Therefore, in the appropriately selected patient, CMIS may be an excellent alternative approach to addressing severe ASD.

Augmented Reality-Assisted Percutaneous Pedicle Screw Instrumentation: A Cadaveric Feasibility and Accuracy Study

Percutaneous pedicle screw instrumentation is the keystone of minimally invasive spine surgery. Percutaneous screw placement demands experience and relies greatly on intra-operative image guidance. This study aims to validate the feasibility and accuracy of augmented-reality (AR)-assisted percutaneous pedicle screw instrumentation. One cadaveric torso was prepared for this study. After a pre-operative computed tomography (CT) scan, the images were transferred to an AR station to generate a 3D hologram. The 3D hologram and navigation images were projected to a pair of goggles with a display screen. With registration, the 3D spine hologram was overlayed onto the cadaver. Bilateral instrumentation from T6 to L5 was performed by two surgeons using AR assistance. A post-operative CT scan was obtained. The Gertzbein–Robbins scale (grade 0–3) was used for accuracy assessment. A total of 24 screws were placed. The overall screw accuracy was 87.5%. There were three major medial breaches that occurred on Rt T6/7/8, which were the most distant screws from the iliac reference. The cause of the three major medial breaches appeared to be related to their distance from the iliac reference. AR-assisted percutaneous pedicle screw instrumentation could improve anatomical visualization, facilitate surgical workflow, and provide an intuitive way of performing surgery.

Development of a decision-making pathway for utilizing standalone lateral lumbar interbody fusion

PURPOSE

To develop a decision-making pathway for primary SA-LLIF. Furthermore, we analyzed the agreement of this pathway and compared outcomes of patients undergoing either SA-LLIF or 360-LLIF.

METHOD

A decision-making pathway for SA-LLIF was created based on the results of interviews/surveys of senior spine surgeons with over 10 years of experience. Internal validity was retrospectively evaluated using consecutive patients undergoing either SA-LLIF or 360-LLIF between 01/2018 and 07/2020 with 3D-printed Titanium cages. An outcome assessment looking primarily at revision surgery and secondary at cage subsidence, changes in disk and foraminal height, global and segmental lumbar lordosis, duration of surgery, estimated blood loss, and length of stay was carried out.

RESULTS

78 patients with 124 treated levels (37 SA-LLIF, 41 360-LLIF) were retrospectively analyzed. The pathway showed a direct agreement (SA-LLIF) of 100.0% and an indirect agreement (360-LLIF) of 95.1%. Clinical follow-up averaged 13.5 ± 6.5 months including 4 revision surgeries in the 360-LLIF group and none in the SA-LLIF group (p = 0.117). Radiographic follow-up averaged 9.5 ± 4.3 months, with no statistically significant difference in cage subsidence rate between the groups (p = 0.440). Compared to preoperative images, patients in both groups showed statistically significant changes in disk height (p < 0.001), foraminal height (p < 0.001), as well as restoration of segmental lordosis (p < 0.001 and p = 0.018). The SA-LLIF group showed shorter duration of surgery, less estimated blood loss and shorter LOS (p < 0.001).

CONCLUSION

The proposed decision-making pathway provides a guide to adequately select patients for SA-LLIF. Further studies are needed to assess the external applicability and validity.

LEVEL OF EVIDENCE III

Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding.

Is Less Really More? Economic Evaluation of Minimally Invasive Surgery

STUDY DESIGN

Review.

OBJECTIVE

A comparative overview of cost-effectiveness between minimally invasive versus and equivalent open spinal surgeries.

METHODS

A literature search using PubMed was performed to identify articles of interest. To maximize the capture of studies in our initial search, we combined variants of the terms "cost," "minimally invasive," "spine," "spinal fusion," "decompression" as either keywords or MeSH terms. PearlDiver database was queried for open and minimally invasive surgery (MIS; endoscopic or percutaneous) reimbursements between Q3 2015 and Q2 2018.

RESULTS

In general, MIS techniques appeared to decrease blood loss, shorten hospital lengths of stay, mitigate complications, decrease perioperative pain, and enable quicker return to daily activities when compared to equivalent open surgical techniques. With regard to cost, primarily as a result of these latter benefits, MIS was associated with lower costs of care when compared to equivalent open techniques. However, cost reporting was sparse, and relevant methodology was inconsistent throughout the spine literature. Within the PearlDiver data sets, MIS approaches had lower reimbursements than open approaches for both lumbar posterior fusion and discectomy.

CONCLUSIONS

Current data suggests that overall cost-savings may be incurred with use of MIS techniques. However, data reporting on costs lacks in uniformity, making it difficult to formulate any firm conclusions regarding any incremental improvements in cost-effectiveness that may be incurred when utilizing MIS techniques when compared to equivalent open techniques.