A Systematic Review of Complications Following Minimally Invasive Spine Surgery Including Transforaminal Lumbar Interbody Fusion

An Update in Complication Rates Associated With Anterior Lumbar Surgery: A Systematic Review and Meta-Analysis

STUDY DESIGN

Systematic Review and meta-analysis.

OBJECTIVE

To conduct an updated systematic review and meta-analysis of complications associated with different anterior fusion techniques/approaches and adjuvant resources (i.e., computed tomography angiography (CTA), rhBMP-2, and access surgeons).

METHODS

A systematic review was conducted from 1/1/2014-4/1/2024 for studies evaluating the incidence of complications associated with anterior lumbar procedures. Comparisons of complications were made between surgical approach, use of CTA, rhBMP-2, and access surgeons. Meta-analyses were conducted using a generalized linear mixed model.

RESULTS

54 studies were included in the final analysis with 8066 patients and an average follow-up of 31.2 months. The overall complication rate associated with anterior lumbar surgery was 13.1%, including an intraoperative complication rate of 3.8%, postoperative complication rate of 7.4%, infection rate of 1.5%, and reoperation rate of 1.7%. Forest plot analysis showed no significant difference in overall complication rates between open and mini-open techniques, although mini-open techniques were associated with lower overall reoperation rates. The use of CTA was associated with an increase in intraoperative and overall complications, and the use of an access surgeon was associated with a decreased risk of reoperation. The use of rhBMP-2 was not associated with overall complication risk.

CONCLUSIONS

While anterior lumbar surgery provides numerous benefits, surgeons and patients alike should be aware of the complication and safety profile prior to surgery. High quality studies are warranted to help elucidate the true benefit of certain techniques and adjuvant resources in reducing complications.

En bloc resection of the ligamentum flavum for bilateral decompression in unilateral biportal endoscopic transforaminal lumbar interbody fusion: a 2-year follow-up study

BACKGROUND

Unilateral biportal endoscopic transforaminal lumbar interbody fusion (UBE-TLIF) is a minimally invasive procedure for treating lumbar degenerative diseases. However, the use of endoscopic lumbar interbody fusion does not completely eliminate the risk of dural and nerve root injuries. This study has refined UBE-TLIF to incorporate en bloc resection of the ligamentum flavum for bilateral decompression and aim to detail the surgical procedure and evaluate the clinical outcomes of this modification.

METHODS

This study analyzes the outcomes of 109 consecutive patients treated by a single surgeon for lumbar degenerative disease using UBE-TLIF. Patients were divided into two groups: Group A (51 patients) underwent en bloc resection of the ligamentum flavum, while Group B (58 patients) underwent routine piecemeal resection. Assessed outcomes included surgery-related complications, operation time, estimated blood loss, postoperative stay, visual analogue scale (VAS) score, and Oswestry Disability Index (ODI). The surgical technique is detailed within the study.

RESULTS

In Group A, no nerve root or dura injuries were observed, whereas Group B reported one case of nerve root injury and three dura tears. The average operation time for Group A was shorter than that for Group B; however, the difference was not statistically significant (P > 0.05). No significant differences were found in the VAS score, ODI, estimated blood loss, or postoperative stay between the groups during follow-up.

CONCLUSIONS

En bloc resection of the ligamentum flavum for bilateral decompression in UBE-TLIF demonstrates satisfactory clinical outcomes and low perioperative complications rates, offering a safe and innovative alternative for the treatment of lumbar degenerative disease.

Minimally-invasive trans-facet lumbar interbody fusion using a dual-dimension expandable cage: preliminary results of a multi-institutional retrospective study

Background

Minimally-invasive trans-facet lumbar interbody fusion (LIF) is an emerging technique that offers the advantages of being safe, enabling decompression, and facilitating patient recovery. An innovative cage that expands in two dimensions has been introduced to restore segmental lordosis and disc height while minimizing the risk of cage subsidence. This study aimed to report our surgical technique of trans-facet LIF utilizing the innovative cag and to report the early clinical outcomes.

Methods

We retrospectively reviewed the medical records and radiographs of patients who underwent trans-facet LIF with dual-dimension expandable cages from two institutions: Duke University Hospital and Vail-Summit Orthopaedics and Neurosurgery. The analysis covered patient demographics, Oswestry Disability Index (ODI), visual analogue scale (VAS) for back pain, surgical data, complications, and radiographic parameters. Clinical outcomes were compared between pre- and one year post-operation, while radiographic outcomes were compared between pre- and three months post-operation.

Results

Twenty patients with a mean age of 61.2 years were included. Seventeen patients (85.0%) had spondylolisthesis, and L4/5 (68.2%) was the most common pathology level. Twelve patients (60.0%) underwent awake surgery, and the mean operative time was 164.5±36.1 minutes, with an estimated blood loss of 64.0±39.5 mL and a hospital stay of 1.75±1.2 days. Four patients (20.0%) experienced cage subsidence; however, none required additional surgery. The VAS score significantly improved from a preoperative average of 7.3±2.7 to 2.6±1.6 one year post-operation (P=0.02). The ODI score also showed a significant decrease, from 48.7±22.9 preoperatively to 16.4±11.1 one year postoperatively (P=0.03). Notably, 80% and 83.3% of patients achieved the minimum clinically important difference in VAS and ODI scores, respectively. The degree of spondylolisthesis was significantly reduced from a median of 5.9 mm preoperatively to 0 mm postoperatively (P<0.001). Additionally, both anterior and posterior disc heights significantly increased after surgery, from 9.8±4.7 to 15.1±2.6 mm (anterior) and from 4.9±3.3 to 10.5±2.2 mm (posterior) (P<0.001 for both). The mean segmental lordosis increased by 2.9 degrees and was associated with cage height (P=0.03), while spinopelvic parameters remained unchanged.

Conclusions

Minimally-invasive trans-facet LIF with dual-dimension expandable cages demonstrates a substantial capacity for spondylolisthesis reduction and disc height restoration, and provides good short-term clinical outcomes. It may be the most appropriate method for deploying this large cage as it allows for a large, unobstructed pathway to the disc. However, future studies are needed to determine the long-term outcomes, including the arthrodesis rate.

Complications in Minimally Invasive Spine Surgery in the Last 10 Years: A Narrative Review

OBJECTIVE

Minimally invasive spine surgery (MISS) employs small incisions and advanced techniques to minimize tissue damage while achieving similar outcomes to open surgery. MISS offers benefits such as reduced blood loss, shorter hospital stays, and lower costs. This review analyzes complications associated with MISS over the last 10 years, highlighting common issues and the impact of technological advancements.

METHODS

A systematic review following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines was conducted using PubMed, MEDLINE, Embase via OVID, and Cochrane databases, covering publications from January 2013 to March 2024. Keywords related to MISS and complications were used. Studies on adult patients undergoing MISS with tubular, uniportal, or biportal endoscopy, reporting intraoperative or postoperative complications, were included. Non-English publications, abstracts, and small case series were excluded. Data on MISS approach, patient demographics, and complications were extracted and reviewed by 2 independent researchers.

RESULTS

The search identified 880 studies, with 137 included after screening and exclusions. Key complications in cervical MISS were hematomas, transient nerve root palsy, and dural tears. In thoracic MISS, complications included cerebrospinal fluid leaks and durotomy. In lumbar MISS, common complications were incidental dural injuries, postoperative neuropathic conditions, and disc herniation recurrences. Complications varied by surgical approach.

CONCLUSION

MISS offers reduced anatomical disruption compared to open surgery, potentially decreasing nerve injury risk. However, complications such as nerve injuries, durotomies, and hardware misplacement still occur. Intraoperative neuromonitoring and advanced technologies like navigation can help mitigate these risks. Despite variability in complication rates, MISS remains a safe, effective alternative with ongoing advancements enhancing its outcomes.

Closing the Gap: The Incidence of Complications in Minimally Invasive Tubular, Endoscopic, and Robotic-Assisted Transforaminal Lumbar Interbody Fusion Procedures

BACKGROUND

The aim of the current study was to compare the incidence of postoperative complications among minimally invasive surgery (MIS) tubular, endoscopic, and robot-assisted transforaminal lumbar interbody fusion (TLIF) techniques.

METHODS

We studied consecutive patients who underwent single-level or multilevel TLIF between 2020 and 2022. Preoperative and postoperative patient-reported outcomes (Visual Analog Scale leg score and Oswestry Disability Index), demographic, and intraoperative variables were recorded. One-way analysis of variance with Bartlett's equal-variance and Pearson chi-squared tests were used.

RESULTS

The study included 170 TLIF patients: 107 (63%) tubular, 42 (25%) endoscopic, and 21 (12%) robot assisted. All 3 TLIF techniques had similar complication rates: tubular 6 (5.6%), endoscopic 2 (4.8%), and robot assisted 1 (4.8%) all occurring within the first 2 weeks. Tubular TLIF reported the lowest incidence of new-onset neurologic symptoms, primarily radiculitis or numbness/tingling, at 2 weeks postoperatively (P < 0.05) with 21 (20%) tubular, 17 (41%) endoscopic, and 9 (43%) robot-assisted patients. There were 2 revisions in the robot-assisted group, while tubular and endoscopic each had one within 1 year. There was no statistical difference in preoperative or postoperative patient-reported outcomes between the TLIF groups.

CONCLUSIONS

The current study demonstrated that tubular, endoscopic, and robot-assisted TLIF procedures had similar complication rates. The tubular MIS TLIF reported fewer new neurologic symptoms compared with endoscopic and robot-assisted TLIF procedures at 2 weeks postoperative, with all groups declining in symptom persistency at later time intervals. Average Visual Analog Scale scores continuously improved up to 1 year postoperatively among all groups.

Dislodgment Effects of Different Cage Arrangements in Posterior Lumbar Interbody Fusion: A Finite Element Study

The vertebral cage has been widely used in posterior lumbar interbody fusion. The risk of cage dislodgment is high for patients undergoing lumbar fusion surgery. Therefore, the main objective of this study was to use a lumbar fusion model to investigate the effects of cage dislodgment on different cage arrangements after PLIF. Finite element analysis was used to compare three PEEK cage placements, together with the fibula-type cage, with respect to the four kinds of lumbar movements. The results revealed that a horizontal cage arrangement could provide a better ability to resist cage dislodgment. Overall lumbar flexion movements were confirmed to produce a greater amount of cage slip than the other three lumbar movements. The lower part of the lumbar fusion segment could create a greater amount of cage dislodgment for all of the lumbar movements. Using an autograft with a fibula as a vertebral cage cannot effectively reduce cage dislodgment. Considering the maximum movement type in lumbar flexion, we suggest that a horizontal arrangement of the PEEK cage might be considered when a single PEEK cage is placed in the fusion segment, as doing so can effectively reduce the extent of cage dislodgment.

Postoperative complications after surgery for lumbar spinal stenosis, assessment using two different data sources

PURPOSE

Lumbar spinal stenosis (LSS) is a prevalent disorder, and surgery for LSS is a common procedure. Postoperative complications occur after any surgery and impose costs for society and costs and additional morbidity for patients. Since complications are relatively rare, medical registries of large populations may provide valuable knowledge. However, recording of complications in registries can be incomplete. To better estimate the true prevalence of complications after LSS surgery, we reviewed two different sources of data and recorded complications for a sample of Norwegian LSS patients.

METHODS

474 patients treated surgically for LSS during 2015 and 2016 at four hospitals reported to a national spine registry (NORspine). Postoperative complications were recorded by patients in NORspine, and we cross-referenced complications documented in NORspine with the patients´ electronic patient records (EPR) to re-test the complication rates. We performed descriptive statistics of complication rates using the two different data sources above, and analyzed the association between postoperative complications and clinical outcome with logistic regression.

RESULTS

The mean (95%CI) patient age was 66.3 (65.3-67.2) years, and 254 (53.6%) were females. All patients were treated with decompression, and 51 (10.7%) received an additional fusion during the index surgery. Combining the two data sources, we found a total rate for postoperative complications of 22.4%, the NORspine registry reported a complication rate of 15.6%, and the EPR review resulted in a complication rate of 16.0%. However, the types of complications were inconsistent across the two data sources. According to NORspine, the frequency of reoperation within 90 days was 0.9% and according to EPR 3.4%. The rates of wound infection were for NORspine 3.1% and EPR review 2.1%. There was no association between postoperative complication and patient reported outcome.

CONCLUSION

Postoperative complications occurred in 22% of LSS patients. The frequency of different postoperative complications differed between the two data sources.

Two-Year Clinical and Radiographic Outcomes for Percutaneous Lumbar Interbody Fusion With an Expandable Titanium Cage Through Kambin's Triangle Without Facetectomy

BACKGROUND

There has been heightened interest in performing percutaneous lumbar interbody fusions (percLIFs) through Kambin's triangle, an anatomic corridor allowing entrance into the disc space. However, due to its novelty, there are limited data regarding the long-term benefits of this procedure. Our objective was to determine the long-term efficacy and durability of the percutaneous insertion of an expandable titanium cage through Kambin's triangle without facetectomy.

METHODS

A retrospective review of patients undergoing percLIF via Kambin's triangle using an expandable titanium cage was performed. Demographics, visual analog scale (VAS) scores, Oswestry Disability Index (ODI), radiographic measurements, perioperative variables, and complications were recorded. VAS, ODI, and radiographic measurements were compared with baseline using the generalized estimating equations assuming normally distributed data. Fusion was assessed with computed tomography (CT) at 1 and 2 years after the procedure.

RESULTS

A total of 49 patients were included. Spondylolisthesis, lumbar lordosis (LL), sacral slope, pelvic tilt, and anterior/posterior disc space height were all significantly improved postoperatively at each time point of 3, 6, 12, and 24 months (P < 0.001). Pelvic incidence-LL mismatch decreased significantly at each follow-up (P < 0.001) with a mean reduction of 4° by 24 months. VAS back scores reduced by >2 points at the 6, 12, and 24 month follow-ups. ODI scores reduced by >15 points at the 12- and 24-month follow-ups. Of the patients who had 1- and 2-year CT images, fusion rates at those time points were 94.4% (17/18) and 87.5% (7/8), respectively. The mean annual rate of surgically significant adjacent segment disease was 2.74% through an average follow-up of 2.74 years.

CONCLUSION

These results highlight that percLIF, a procedure done without an endoscope or facetectomy, can be performed using an expandable titanium cage through Kambin's triangle with excellent radiographic and clinical results.

CLINICAL RELEVANCE

percLIF via Kambin's triangle is a safe and succesful procedure with long-term improvements in both clinical and radiographic outcomes.

LEVEL OF EVIDENCE: 3

The effect of subcutaneous fat and skin-to-lamina distance on complications and functional outcomes of minimally invasive lumbar decompression

PURPOSE

Minimally invasive lumbar decompression (MIS) in obese pzatients is technically challenging due to the use of longer tube retractors. The purpose of this study was to evaluate the impact of the thickness of the soft tissue and subcutaneous fat on complications, revisions, and patient-reported functional outcomes after MIS.

METHODS

This is a retrospective analysis of 148 consecutive patients who underwent minimally invasive lumbar decompression at our institute between 2013 and 2017 and had at least one year of follow-up. Analysis was performed five times, each time the study group was defined by another measure of adiposity: BMI > 30, skin to lamina distance at the site of surgery and at L4 > 6 cm, and subcutaneous fat thickness at the site of surgery and at L4 > 3 cm. Outcomes included intraoperative complications (durotomy or neurological deficit), possibly inadequate decompression (residual disc, reoperation), length of stay, return to the emergency room or readmission, postoperative medical complications, and functional outcomes: visual analog scores for back and leg pain, and Oswestry Disability Index (ODI).

RESULTS

Patients with a thicker layer soft tissue had a significantly higher burden of comorbidities than controls, including higher prevalence of cardiovascular disease (p = 0.002), diabetes (p < 0.001), hypertension (p < 0.001) and higher ASA scores (p = 0.002). Nevertheless, there was no significant difference between the patient groups in surgical and medical complications, functional outcomes, and other assessed outcomes.

CONCLUSION

Our results indicate that minimally invasive lumbar decompression is safe and effective for patients with a thick layer of soft tissue and subcutaneous fat.

Outcome of Ti/PEEK Versus PEEK Cages in Minimally Invasive Transforaminal Lumbar Interbody Fusion

STUDY DESIGN

Retrospective case-control study.

OBJECTIVES

This study aims to present the clinical and radiographical outcomes of the titanium-polyetheretherketone (Ti/PEEK) composite cage compared to those of the standard PEEK cage in patients receiving minimally invasive transforaminal lumbar interbody fusion (MI-TLIF).

METHODS

Patients receiving 1 level MI-TLIF between October 2015 and October 2017 were included with a minimum of 2-year follow-up. The patients were segregated into 2 groups; Ti/PEEK group and PEEK group. Each patient was propensity-matched using preoperative age, sex, and body mass index. Early fusion rate was evaluated by computed tomography at postoperative 6 months. Clinical outcomes were assessed using the visual analog scale (VAS) and Oswestry Disability Index (ODI) scores.

RESULTS

After matching, there were 27 patients included in each group. The demographics, diagnosis, and surgical details were not significantly different between the 2 groups. The 6-month rate was 88.9% in Ti/PEEK group. The fusion rate and cage subsidence rate had no difference between the 2 groups. The complication rate in the Ti/PEEK group was comparable to that in the PEEK group. There was no difference in VAS and ODI scores during a 2-year follow-up period.

CONCLUSIONS

The use of Ti/PEEK composite cage was as safe and effective as the use of PEEK cage in MI-TLIF. The 6-month fusion rate was 88.9%. Our finding revealed comparable clinical results for surgeons using Ti/PEEK composite cages in MI-TLIF compared to those using the PEEK cage.

Biomechanical studies of different numbers and positions of cage implantation on minimally invasive transforaminal interbody fusion: A finite element analysis

BACKGROUND

The position and number of cages in minimally invasive transforaminal interbody fusion (MIS-TLIF) are mainly determined by surgeons based on their individual experience. Therefore, it is important to investigate the optimal number and position of cages in MIS-TLIF.

METHODS

The lumbar model was created based on a 24-year-old volunteer's computed tomography data and then tested using three different cage implantation methods: single transverse cage implantation (model A), single oblique 45° cage implantation (model B), and double vertical cage implantation (model C). A preload of 500 N and a moment of 10 Nm were applied to the models to simulate lumbar motion, and the models' range of motion (ROM), ROM ratio, peak stress of the internal fixation system, and cage were assessed.

RESULTS

The ROM ratios of models A, B, and C were significantly reduced by >71% compared with the intact model under all motions. Although there were subtle differences in the ROM ratio for models A, B, and C, the trends were similar. The peak stress of the internal fixation system appeared in model B of 136.05 MPa (right lateral bending), which was 2.07 times that of model A and 1.62 times that of model C under the same condition. Model C had the lowest cage stress, which was superior to that of the single-cage model.

CONCLUSION

In MIS-TLIF, single long-cage transversal implantation is a promising standard implantation method, and double short-cage implantation is recommended for patients with severe osteoporosis.

History and Evolution of the Minimally Invasive Transforaminal Lumbar Interbody Fusion

The minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) is a popular surgical technique for lumbar arthrodesis, widely considered to hold great efficacy while conferring an impressive safety profile through the minimization of soft tissue damage. This elegant approach to lumbar stabilization is the byproduct of several innovations throughout the past century. In 1934, Mixter and Barr's paper in the New England Journal of Medicine elucidated the role of disc herniation in spinal instability and radiculopathy, prompting surgeons to explore new approaches and instruments to access the disc space. In 1944, Briggs and Milligan published their novel technique, the posterior lumbar interbody fusion (PLIF), involving continuous removal of vertebral bone chips and replacement of the disc with a round bone peg. The following decades witnessed several PLIF modifications, including the addition of long pedicle screws. In 1982, Harms and Rolinger sought to redefine the posterior corridor by approaching the disc space through the intervertebral foramen, establishing the transforaminal lumbar interbody fusion (TLIF). In the 1990s, lumbar spine surgery experienced a paradigm shift, with surgeons placing increased emphasis on tissuesparing minimally invasive techniques. Spurred by this revolution, Foley and Lefkowitz published the novel MIS-TLIF technique in 2002. The MIS-TLIF has demonstrated comparable surgical outcomes to the TLIF, with an improved safety profile. Here, we present a view into the history of the posterior-approach treatment of the discogenic radiculopathy, culminating in the MIS-TLIF. Additionally, we evaluate the hallmark characteristics, technical variability, and reported outcomes of the modern MIS-TLIF and take a brief look at technologies that may define the future MIS-TLIF.

Full Endoscopic Posterolateral Transarticular Lumbar Interbody Fusion Using Transparent Plastic Working Tubes: Technical Note and Preliminary Clinical Results

Background

A series of full-endoscopic lumbar interbody fusions have been reported, but special fusion cages or operating instruments are often needed, and there are many complications in the operation and the learning curve is long. We have used a single portal endoscopic system for lumbar interbody fusion in a novel posterolateral transarticular approach, which will take advantage of the incision for pedicle screw insertion and avoid nerve root damage by using a transparent plastic working tube. The purpose of this study was to present the surgical technique of full endoscopic posterolateral transarticular lumbar interbody fusion (FE-PTLIF) and to analyze the preliminary clinical results.

Methods

A total of 39 patients (17 men and 22 women; mean age [x̅ ± s] 55.2 ± 12.2 years) have been enrolled in this retrospective study between March 2019 and January 2021 in the Second Affiliated Hospital of Chongqing Medical University. All patients were treated with full endoscopic lumbar interbody fusion via posterolateral transarticular approach with a transparent plastic working tube. Demographic characteristics, diagnosis, operative time, and estimated blood loss were evaluated. Intraoperative photo and perioperative imaging were recorded. The preoperative and postoperative clinical data were collected for statistical analysis.

Results

The preliminary clinical follow-up data achieved good results. No patients had serious postoperative complications and none of these patients required revision surgery during the perioperative or follow-up period. We compared the visual analogue scale and Oswestry disability index scores before and after surgery. The differences were statistically significant (P < 0.05). The mean total blood loss (including drainage blood) was 54.4 ± 20.3 ml. The mean operative time was 130.5 ± 23.8 min. At the last follow-up, the fusion rate of the lumbar intervertebral space was 100%.

Conclusions

This novel posterolateral transarticular approach and transparent plastic working tube can reduce the difficulty of the operation, so that the conventional intervertebral fusion cage [bullet-shaped polyetheretherketone (PEEK) nonexpandable fusion cage] and surgical instruments can be used in the full endoscopic lumbar intervertebral fusion surgery, which can reduce the cost and improve the efficiency of the operation.

Ten-Year Outcomes of Minimally Invasive Versus Open Transforaminal Lumbar Interbody Fusion in Patients With Single-Level Lumbar Spondylolisthesis

STUDY DESIGN

A retrospective observational study.

OBJECTIVE

This study investigated the clinical and radiological results of minimally invasive (MI) versus open transforaminal lumbar interbody fusion (TLIF) in patients with single-level lumbar spondylolisthesis over a 10-year period.

SUMMARY OF BACKGROUND DATA

Few studies have compared 10-year follow-up outcomes between MI-TLIF and open TLIF.

METHODS

We retrospectively collected the outcome data of patients with single-level lumbar spondylolisthesis who underwent TLIF procedures using an MI (n = 108) or open (n = 53) approach. Fifty-two (48%) and 31 (58%) patients in the MI-TLIF and open TLIF groups, respectively, completed the 10-year follow-up. A primary clinical outcome included the Oswestry Disability Index (ODI) as well as visual analog scale (VAS) scores for back and leg pain at baseline and at 2, 5, and 10 years postoperatively. The radiographic fusion rate and incidence of secondary surgery due to adjacent segment disease were assessed at 2, 5, and 10 years postoperatively.

RESULTS

Intraoperative blood loss and length of hospitalization were significantly lower in the MI-TLIF group than in the open TLIF group. At 2 years postoperatively, the ODI and VAS scores for back and leg pain were significantly lower in the MI-TLIF group than in the open TLIF group. No significant differences were found in VAS scores for back and leg pain or ODI scores between the two groups at 10 years postoperatively. Radiographic fusion rates and prevalence of secondary surgery for adjacent segment disease were not significantly different between the groups at 10 years postoperatively.

CONCLUSION

Efficacy of MI-TLIF for patients with single-level lumbar spondylolisthesis is comparable to that of open TLIF over 10-years. However, MI-TLIF may have superior perioperative recovery and 2-year postoperative functional outcomes than open TLIF.Level of Evidence: 3.

Indirect Lumbar Decompression Combined With or Without Additional Direct Posterior Decompression: A Systematic Review

STUDY DESIGN

Systematic review.

OBJECTIVE

Indirect decompression via lateral lumbar interbody fusion (LLIF) can ameliorate central and foraminal lumbar stenosis. In severe central stenosis, additional posterior direct decompression is utilized. The aim of this review is to synthesize existing literature on these 2 techniques and identify significant differences in outcomes between isolated indirect decompression via LLIF and combined indirect decompression supplemented with direct posterior decompression.

METHODS

A database search algorithm was utilized to query MEDLINE, COCHRANE, and EMBASE to identify literature reporting adult decompression study groups that involved an oblique or lateral fusion approach through September 2020. Improvement in outcomes measures and complication rates were pooled and tested for significance.

RESULTS

A total of 110 publications were assessed with 15 studies meeting inclusion criteria, including 557 patients and 1008 levels. Mean age was 63.1 years with BMI of 27.5 kg/m². For the combined indirect and direct decompression cohort, lumbar lordosis (LL) increased 133.9%, from 22.8^o to 48.7^o, while the indirect decompression cohort LL increased 8.9%, from 41.9^o to 45.5^o. Difference in LL improvement between cohorts was insignificant (P > .05). Oswestry Disability Index (ODI) decreased from 36.5 to 19.4 in the combined indirect and direct decompression cohort, and from 44.4 to 23.1 in the indirect decompression cohort. ODI reduction was insignificant (P = .053).

CONCLUSIONS

Prior studies of both indirect decompression as well as combined indirect and direct decompression of lumbar spine stenosis are limited by small samples, heterogeneous populations, and lack of direct comparisons. Both procedures result in improved function and pain postoperatively with direct decompression restoring more lordosis in patients with worse preoperative alignment.

Finite Element Analysis of a Novel Fusion Strategy in Minimally Invasive Transforaminal Lumbar Interbody Fusion

Purpose

To evaluate the biomechanics of a novel fusion strategy (hybrid internal fixation+horizontal cage position) in minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF).

Methods

MIS-TLIF finite element models for three fusion strategies were created based on computed tomography images, namely, Model-A, hybrid internal fixation (ipsilateral pedicle screw and contralateral translaminar facet screw fixation)+horizontal cage position; Model-B, bilateral pedicle screw (BPS) fixation+horizontal cage position; and Model-C, BPS fixation+oblique 45° cage position. A preload of 500 N and a moment of 10 Nm were applied to the models to simulate lumbar motion, and the models' range of motion (ROM), peak stress of the internal fixation system, and cage were assessed.

Results

The ROM for Models A, B, and C were not different (P > 0.05) but were significantly lower than the ROM of Model-INT (P < 0.0001). Although there were subtle differences in the ROM ratio for Models A, B, and C, the trend was similar. The peak stress of the internal fixation system was significantly higher in Model-A than that of Models B and C, but only the difference between Models A and B was significant (P < 0.05). The peak stress of the cage in Model-A was significantly lower than that of Models B and C (P < 0.01).

Conclusion

Hybrid internal fixation with horizontal single cage implantation can provide the same biomechanical stability as traditional fixation while reducing peak stress on the cage and vertebral endplate.

Ligamentum-preserved/Temporary Preserved Minimally Invasive Transforaminal Lumbar Interbody Fusion for Lumbar Spondylolisthesis: Technical Note and 2-year Follow-up

STUDY DESIGN

Prospective study.

OBJECTIVE

The aim of this study was to prospectively assess the clinical outcomes of modified minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) for the treatment of singlesegment lumbar spondylolisthesis.

SUMMARY OF BACKGROUND DATA

MIS-TLIF is a safe and effective procedure in the treatment of lumbar degenerative disease. To avoid durotomy and nerve root injury, we modified the surgical order of MIS-TLIF such that the interbody fusion procedure was performed before the decompression procedure.

METHODS

One hundred thirty-nine patients with single-segment lumbar spondylolisthesis were separated into two groups. Sixty-seven patients underwent modified MIS-TLIF (group A). In group B, 72 patients underwent routine MIS-TLIF. The Japanese Orthopedic Association (JOA) score and the visual analogue scale (VAS) scores for lower back pain (LBP) and leg pain were assessed during the postoperative follow-up, and the lumbar interbody fusion rate was evaluated by CT scanning.

RESULTS

The mean operative time, incision length, average blood loss, and incision pain level were not significantly different (P  > 0.05) between the two groups. No nerve root or dural injuries were observed in group A. In group B, there were two cases of dural injury and three cases of nerve root injury. One patient experienced temporary numbness and weakness on dorsiflexion of the foot, which recovered in 3 months. No differences were identified between the two groups when postoperative JOA scores, back pain, leg pain VAS scores, or the lumbar interbody fusion rate.

CONCLUSION

Both methods are effective in the treatment of lumbar degenerative disease. Modified MIS-TLIF is a safe and effective procedure that can significantly reduce the occurrence of injury to the dura and nerve root during decompression and the interbody fusion procedure.Level of Evidence: 3.

Patient outcomes after circumferential minimally invasive surgery compared with those of open correction for adult spinal deformity: initial analysis of prospectively collected data

OBJECTIVE

Circumferential minimally invasive spine surgery (cMIS) for adult scoliosis has become more advanced and powerful, but direct comparison with traditional open correction using prospectively collected data is limited. The authors performed a retrospective review of prospectively collected, multicenter adult spinal deformity data. The authors directly compared cMIS for adult scoliosis with open correction in propensity-matched cohorts using health-related quality-of-life (HRQOL) measures and surgical parameters.

METHODS

Data from a prospective, multicenter adult spinal deformity database were retrospectively reviewed. Inclusion criteria were age > 18 years, minimum 1-year follow-up, and one of the following characteristics: pelvic tilt (PT) > 25°, pelvic incidence minus lumbar lordosis (PI-LL) > 10°, Cobb angle > 20°, or sagittal vertical axis (SVA) > 5 cm. Patients were categorized as undergoing cMIS (percutaneous screws with minimally invasive anterior interbody fusion) or open correction (traditional open deformity correction). Propensity matching was used to create two equal groups and to control for age, BMI, preoperative PI-LL, pelvic incidence (PI), T1 pelvic angle (T1PA), SVA, PT, and number of posterior levels fused.

RESULTS

A total of 154 patients (77 underwent open procedures and 77 underwent cMIS) were included after matching for age, BMI, PI-LL (mean 15° vs 17°, respectively), PI (54° vs 54°), T1PA (21° vs 22°), and mean number of levels fused (6.3 vs 6). Patients who underwent three-column osteotomy were excluded. Follow-up was 1 year for all patients. Postoperative Oswestry Disability Index (ODI) (p = 0.50), Scoliosis Research Society-total (p = 0.45), and EQ-5D (p = 0.33) scores were not different between cMIS and open patients. Maximum Cobb angles were similar for open and cMIS patients at baseline (25.9° vs 26.3°, p = 0.85) and at 1 year postoperation (15.0° vs 17.5°, p = 0.17). In total, 58.3% of open patients and 64.4% of cMIS patients (p = 0.31) reached the minimal clinically important difference (MCID) in ODI at 1 year. At 1 year, no differences were observed in terms of PI-LL (p = 0.71), SVA (p = 0.46), PT (p = 0.9), or Cobb angle (p = 0.20). Open patients had greater estimated blood loss compared with cMIS patients (1.36 L vs 0.524 L, p < 0.05) and fewer levels of interbody fusion (1.87 vs 3.46, p < 0.05), but shorter operative times (356 minutes vs 452 minutes, p = 0.003). Revision surgery rates between the two cohorts were similar (p = 0.97).

CONCLUSIONS

When cMIS was compared with open adult scoliosis correction with propensity matching, HRQOL improvement, spinopelvic parameters, revision surgery rates, and proportions of patients who reached MCID were similar between cohorts. However, well-selected cMIS patients had less blood loss, comparable results, and longer operative times in comparison with open patients.

Smoking Is Associated With Lower Satisfaction in Nondiabetic Patients Undergoing Minimally Invasive Single-level Transforaminal Lumbar Interbody Fusion

STUDY DESIGN

This was a retrospective review of prospectively collected registry data.

OBJECTIVE

The objective of this study was to investigate the effect of smoking on 2 years postoperative functional outcomes, satisfaction, and radiologic fusion in nondiabetic patients undergoing minimally invasive transforaminal lumbar interbody fusion (TLIF) for degenerative spine conditions.

SUMMARY OF BACKGROUND DATA

There is conflicting data on the effect of smoking on long-term functional outcomes following lumbar fusion. Moreover, there remains a paucity of literature on the influence of smoking within the field of minimally invasive spine surgery.

METHODS

Prospectively collected registry data of nondiabetic patients who underwent primary single-level minimally invasive TLIF in a single institution was reviewed. Patients were stratified based on smoking history. All patients were assessed preoperatively and postoperatively using the Numerical Pain Rating Scale for back pain and leg pain, Oswestry Disability Index, Short-Form 36 Physical and Mental Component Scores. Satisfaction was assessed using the North American Spine Society questionnaire. Radiographic fusion rates were compared.

RESULTS

In total, 187 patients were included, of which 162 were nonsmokers, and 25 had a positive smoking history. In our multivariate analysis, smoking history was insignificant in predicting for minimal clinically important difference attainment rates in Physical Component Score and fusion grading outcomes. However, in terms of satisfaction score, positive smoking history remained a significant predictor (odds ratio=4.7, 95% confidence interval: 1.10-20.09, P=0.036).

CONCLUSIONS

Nondiabetic patients with a positive smoking history had lower satisfaction scores but comparable functional outcomes and radiologic fusion 2 years after single-level TLIF. Thorough preoperative counseling and smoking cessation advice may help to improve patient satisfaction following minimally invasive spine surgery.

LEVEL OF EVIDENCE

Level III-nonrandomized cohort study.

Efficacy and safety of percutaneous transforaminal endoscopic surgery (PTES) compared with MIS-TLIF for surgical treatment of lumbar degenerative disease in elderly patients: A retrospective cohort study

Objectives

To evaluate the efficacy and safety of PTES for surgical treatment of lumbar degenerative disease (LDD) including lumbar disc herniation, lateral recess stenosis, intervertebral foraminal stenosis and central spinal canal stenosis in elderly patients compared with MIS-TLIF.

Methods

From November 2016 to December 2018, 84 elderly patients (>70 years old) of single-level LDD with neurologic symptoms underwent the surgical treatment. 45 patients were treated using PTES under local anesthesia in group 1 and 39 patients treated using MIS-TLIF in group 2. Preoperative, postoperative back and leg pain were evaluated using Visual analog scale (VAS) and the results were determined with Oswestry disability index (ODI) at 2-year follow-up. All complications were recorded.

Results

PTES group shows significantly less operation time (55.6 ± 9.7 min vs. 97.2 ± 14.3 min, P < 0.001), less blood loss [11(2-32) ml vs. 70(35-300) ml, P < 0.001], shorter incision length (8.4 ± 1.4 mm vs. 40.6 ± 2.7 mm, P < 0.001), less fluoroscopy frequency [5(5-10) times vs. 7(6-11) times, P < 0.001] and shorter hospital stay[3(2-4) days vs. 7(5-18) days, P < 0.001] than MIS-TLIF group does. Although there was no statistical difference of leg VAS scores between two groups, back VAS scores in PTES group were significantly lower than those in MIS-TLIF group during follow-ups after surgery (P < 0.001). ODI of PTES group was also significantly lower than that of MIS-TLIF group at 2-year follow-up (12.3 ± 3.6% vs. 15.7 ± 4.8%, P < 0.001).

Conclusion

Both PTES and MIS-TLIF show favorable clinical outcomes for LDD in elderly patients. Compared with MIS-TLIF, PTES has the advantages including less damage of paraspinal muscle and bone, less blood loss, faster recovery, lower complication rate, which can be performed under local anesthesia.

[Reasons analysis on unplanned reoperation of degenerative lumbar spine diseases]

Objective

To review the research on the reasons of unplanned reoperation (URP) for degenerative lumbar spine diseases, and to provide new ideas for improving the quality of surgery for degenerative lumbar spine diseases.

Methods

The literature about the URP of degenerative lumbar spine diseases at home and abroad in recent years was reviewed and analyzed.

Results

At present, the reasons for URP include surgical site infection (SSI), hematoma formation, cerebrospinal fluid leakage (CSFL), poor results of surgery, and implant complications. SSI and hematoma formation are the most common causes of URP, which happen in a short time after surgery; CSFL also occurs shortly after surgery but is relatively rare. Poor surgical results and implant complications occurred for a long time after surgery. Factors such as primary disease and surgical procedures have an important impact on the incidence of URP.

Conclusion

The main reasons for URP are different in various periods after lumbar spine surgery. Interventions should be given to patients with high-risk URP, which thus can reduce the incidence of URP and improve the surgery quality and patients' satisfaction.

Decompression Using Minimally Invasive Surgery for Lumbar Spinal Stenosis Associated with Degenerative Spondylolisthesis: A Review

Lumbar spinal stenosis (LSS), which often occurs concurrently with degenerative spondylolisthesis (DS), is a common disease in the elderly population, affecting the quality of life of aged people significantly. Notwithstanding the frequently good effect of conservative therapy on LSS, a minority of the patients ultimately require surgery. Surgery for LSS aims to decompress the narrowed spinal canals with preservation of spinal stability. Traditional open surgery, either pure decompression or decompression with fusion, was considered effective for the treatment of LSS with or without DS. However, the long-term clinical outcomes of traditional open surgery are still unclear. Moreover, the disadvantages of conventional open surgery are extensive, examples including tissue injuries or secondary instability, with limited outcomes and significant reoperation rates. With the development and improvement of surgical tools, various minimally invasive spine surgery (MISS) methods, including indirect decompression techniques of interspinous process devices (IPDs) and direct decompression techniques such as microscopic spine surgery or endoscopic spine surgery (ESS), have been updated with enhancement. IPDs, such as Superion devices, were reported to behave with comparable physical function, disability, and symptoms outcomes to laminectomy decompression. As an emerging technique of MISS, ESS has beneficial hallmarks including minimal tissue injuries, reduced complication rates, and shortened recovery periods, thus gaining popularity in recent years. ESS can be classified in terms of endoscopic hallmarks and approaches. Predictably, with the continuous development and gradual maturity, MISS is expected to replace traditional open surgery widely in the surgical treatment of LSS associated with DS in the future.

Stable Low-Grade Degenerative Spondylolisthesis Does Not Compromise Clinical Outcome of Minimally Invasive Tubular Decompression in Patients with Spinal Stenosis

Background and Objectives: In recent literature, the routine addition of arthrodesis to decompression for lumbar spinal stenosis (LSS) with concomitant stable low-grade degenerative spondylolisthesis remains controversial. The purpose of this study is to compare the clinical outcome, complication and re-operation rates following minimally invasive (MIS) tubular decompression without arthrodesis in patients suffering from LSS with or without concomitant stable low-grade degenerative spondylolisthesis. Materials and Methods: This study is a retrospective review of prospectively collected data. Ninety-six consecutive patients who underwent elective MIS lumbar decompression with a mean follow-up of 27.5 months were included in the study. The spondylolisthesis (S) group comprised 53 patients who suffered from LSS with stable degenerative spondylolisthesis, and the control (N) group included 43 patients suffering from LSS without spondylolisthesis. Outcome measures included complications and revision surgery rates. Pre- and post-operative visual analog scale (VAS) for both back and leg pain was analyzed, and the Oswestry Disability Index (ODI) was used to evaluate functional outcome. Results: The two groups were comparable in most demographic and preoperative variables. VAS for back and leg pain improved significantly following surgery in both groups. Both groups showed significant improvement in their ODI scores, at one and two years postoperatively. The average length of hospital stay was significantly higher in patients with spondylolisthesis (p-value< 0.01). There was no significant difference between the groups in terms of post-operative complications rates or re-operation rates. Conclusions: Our results indicate that MIS tubular decompression may be an effective and safe procedure for patients suffering from LSS, with or without degenerative stable spondylolisthesis.

Development and Initial Internal Validation of a Novel Classification System for Perioperative Expectations Following Minimally Invasive Degenerative Lumbar Spine Surgery

STUDY DESIGN

This was a prospective consecutive clinical cohort study.

OBJECTIVE

The purpose of our study was to develop and provide an initial internal validation of a novel classification system that can help surgeons and patients better understand their postoperative course following the particular minimally invasive surgery (MIS) and approach that is utilized.

SUMMARY OF BACKGROUND DATA

Surgeons and patients are often attracted to the option of minimally invasive spine surgery because of the perceived improvement in recovery time and postsurgical pain. A classification system based on the impact of the surgery and surgical approach(es) on postoperative recovery can be particularly helpful.

METHODS

Six hundred thirty-one patients who underwent MIS lumbar/thoracolumbar surgery for degenerative conditions of the spine were included. Perioperative outcomes-operative time, estimated blood loss, postsurgical length of stay (LOS), 90-day complications, postoperative day zero narcotic requirement [in Morphine Milligram Equivalent (MME)], and need for intravenous patient-controlled analgesia (IV PCA).

RESULTS

Postoperative LOS and postoperative narcotic use were deemed most clinically relevant, thus selected as primary outcomes. Type of surgery was significantly associated with all outcomes (P<0.0001), except intraoperative complications. Number of levels for fusion was significantly associated with operative time, in-hospital complications, 24 hours oral MME, and the need for IV PCA and LOS (P<0.0001). Number of surgical approaches for lumbar fusion was significantly associated with operative time, 24 hours oral MME, need for IV PCA and LOS (P<0.001). Based on these parameters, the following classification system ("Qureshi-Louie classification" for MIS degenerative lumbar surgery) was devised: (1) Decompression-only; (2) Fusion-1 and 2 levels, 1 approach; (3) Fusion-1 level, 2 approaches; (4) Fusion-2 levels, 2 approaches; (5) Fusion-3+ levels, 2 approaches.

CONCLUSIONS

We present a novel classification system and initial internal validation to describe the perioperative expectations following various MIS surgeries in the degenerative lumbar spine. This initial description serves as the basis for ongoing external validation.

Incidental Durotomy Following Surgery for Degenerative Lumbar Disease and the Impact of Minimally Invasive Surgical Technique on the Rate and Need for Surgical Revision: A Case Series

BACKGROUND

Incidental durotomy (ID) is a common complication during lumbar spine surgery. A paucity of literature has studied the impact of minimally invasive surgery (MIS) on durotomy rates and strategies for repair as compared to open surgery.

OBJECTIVE

To examine the impact that MIS techniques have on the durotomy rate, repair techniques, and need for surgical revision following surgery for degenerative lumbar disease as compared to open technique.

METHODS

A single-center retrospective review of consecutive cases between 2013 and 2016 was performed. All patients underwent lumbar decompression with or without instrumented fusion for degenerative pathology using either open posterior or MIS techniques. ID rate, closure technique, and need for surgical revision related to the durotomy were recorded.

RESULTS

A total of 1,196 patients were included with an overall ID rate of 6.8%. There was no difference between open or minimally invasive surgical techniques (P = .14). There was a higher durotomy rate with open technique in patients that underwent decompression with fusion (P = .03) as well as in revision cases (P = .02). Primary repair was feasible more frequently in the open group (P = .001), whereas use of dural substitute (P < .001) was more common in the MIS group. Fibrin sealant was used routinely in both groups (P = .34). There were no failed repairs, regardless of technique used.

CONCLUSION

MIS techniques may reduce durotomies in cases involving instrumentation or revisions. Use of dural substitute onlay and fibrin sealant was effective at preventing reoperation. Both MIS and open techniques result in a low rate of future surgical revision when a durotomy occurs.

Accelerated Recovery Program for Patients with Polysegmental Degenerative Lumbar Spine Disease

The aim of the study was to evaluate the effectiveness of the accelerated recovery program for patients with polysegmental degenerative diseases of the lumbar spine.

Minimally Invasive Transforaminal Lumbar Interbody Fusion Using Augmented Reality Surgical Navigation for Percutaneous Pedicle Screw Placement

STUDY DESIGN

This was a retrospective observational study.

OBJECTIVE

The aim of this study was to evaluate the accuracy of percutaneous pedicle screw placement using augmented reality surgical navigation during minimally invasive transforaminal lumbar interbody fusion (TLIF).

SUMMARY OF BACKGROUND DATA

Augmented reality-based navigation is a new type of computer-assisted navigation where video cameras are used instead of infrared cameras to track the operated patients and surgical instruments. This technology has not so far been clinically evaluated for percutaneous pedicle screw placement.

MATERIALS AND METHODS

The study assessed percutaneous pedicle screw placement in 20 consecutive patients who underwent single-level minimally invasive TLIF using augmented reality surgical navigation. Facet joint violation and depression by the inserted pedicle screws were evaluated. Secondary outcome such as radiation dose exposure, fluoroscopy time, and operative time were collected for 3 phases of surgery: preparation phase, pedicle screw placement, and decompression with cage placement.

RESULTS

A clinical accuracy for screw placement within the pedicle (Gertzbein 0 or 1) of 94% was achieved. One screw violated the facet joint with a transarticular pathway. The screw head did not depress the facet in 54%. The use of fluoroscopy during navigation correlated with patient body-mass index (r=0.68, P<0.0001). The pedicle screw placement time corresponded to 36±5% of the total operative time of 117±11 minutes. A statistically significant decrease of 10 minutes in operative time was observed between the first and last 10 procedures which corresponded to the pedicle screw placement time decrease (48±9 vs. 38±7 min, P=0.0142). The learning curve model suggests an ultimate operative time decrease to 97 minutes.

CONCLUSION

Augmented reality surgical navigation can be clinically used to place percutaneous screws during minimally invasive TLIF. However, the lack of tracking of the location of the device requires intraoperative fluoroscopy to monitor screw insertion depth especially in obese patients.

LEVEL OF EVIDENCE

Level III.

MIS-TLIF versus O-TLIF for single-level degenerative stenosis: study protocol for randomised controlled trial

INTRODUCTION

Patients with symptomatic single-level combination of degenerative stenosis and low-grade spondylolisthesis are often treated by nerve root decompression and spinal fusion. The gold standard is traditional open decompression and fusion, but minimally invasive method is more and more prevailing. However, there is lack of high-quality studies comparing these two techniques in order to obtain the advantages and certain indications to use one of these methods. The current study includes clinical, safety and radiological endpoints to determine the effectiveness of minimally invasive decompression and fusion (MIS-TLIF) over the traditional open one (O-TLIF).

METHODS AND ANALYSIS

All patients aged 40-75 years with neurogenic claudication or bilateral radiculopathy caused by single-level combination of degenerative stenosis and low-grade spondylolisthesis, confirmed by MRI with these symptoms persisting for at least 3 months prior to surgery, are eligible. Patients will be randomised into MIS-TLIF or traditional O-TLIF. The primary outcome measure is Oswestry Disability Index at 3-month follow-up term. The secondary outcomes are patient-reported outcome measures by the number of clinical scales, radiological parameters including sagittal balance parameters, safety endpoints and cost-effectiveness of each method. All patients will be analysed preoperatively, as well as on the 14th day of hospital stay (or on the day of hospital discharge), 3 months, 6 months, 12 months and 24 months postoperatively. The study has the design of a parallel group to demonstrate the non-inferior clinical results of MIS-TLIF compared with the traditional O-TLIF.

ETHICS AND DISSEMINATION

The study will be performed according to Helsinki Declaration. The study protocol was approved by the Local Ethical Committee of Priorov National Medical Research Center of Traumatology and Orthopedics in August 2020. Preliminary and final results will be presented in peer-reviewed journals, especially orthopaedic and spine surgery journals, at national and international congresses.

TRIAL REGISTRATION NUMBER

NCT04594980.

Use of Intraoperative Computed Tomography Improves Outcome of Minimally Invasive Transforaminal Lumbar Interbody Fusion: A Single-Center Retrospective Cohort Study

OBJECTIVE

To provide data about surgical workflow, accuracy, complications, radiation exposure, and learning curve effect in patients who underwent minimally invasive (MIS) transforaminal lumbar interbody fusion with navigation coupled with mobile intraoperative computed tomography.

METHODS

A retrospective analysis was performed of data from consecutive patients who underwent single- or double-level MIS transforaminal lumbar interbody fusion at a single institution; mobile intraoperative computed tomography combined with a navigation system was used as the sole intraoperative imaging method to place pedicular screws; decompression and interbody fusion were performed through a 22-mm tubular retractor. Clinical data, perioperative complications, accuracy of pedicular screw placement, and radiation exposure were analyzed. A learning curve effect on surgical time and accuracy was assessed.

RESULTS

A total of 408 screws in 100 patients were analyzed. In all cases, spinal navigation allowed for identification of pedicular trajectories and greatly facilitated nerve root decompression through the MIS approach. Overall accuracy according to Heary classification was 95.3%. Nineteen screws (4.7%) presented a minor lateral breach (<2 mm), not clinically significant. Surgical time, blood loss, and patient radiation exposure compared favorably with reported values from other series using three-dimensional navigation. A learning curve effect on surgical time, but not on screw accuracy, was identified.

CONCLUSIONS

MIS transforaminal lumbar interbody fusion can now be performed without any radiation exposure to the surgeon and operating room staff, with almost absolute accuracy during screw positioning and tubular decompression. A learning curve effect on surgical time, but not on overall screw accuracy, may be expected.

Neurosurgery versus orthopedic surgery: Who has better access to minimally invasive spinal technology?

Background:

Our aim was to evaluate differences in neurosurgeons versus orthopedists access to technologies needed to perform minimally invasive spine surgeries (MISS) in Latin America.

Methods:

We sent a survey to members of AO Spine Latin America (January 2020), and assessed the following variables; nationality, level of hospital (primary, secondary, and tertiary), number of spinal operations performed per year, spinal pathologies addressed, the number of minimally invasive spine operations performed/year, and differences in access to MISS spinal technology between neurosurgeons and orthopedists.

Results:

Responses were returned from 306 (25.6) members of AO Spine Latin America representing 20 different countries; 57.8% of respondents were orthopedic surgeons and 42.4% had over 10 years of experience. Although both specialties reported a lack of access to most of the technologies, the main difference between the two was greater utilization/access of neurosurgeons to operating microscope (e.g., 84% of the neurosurgeons vs. 39% of orthopedic spine surgeons).

Conclusion:

Although both specialties have limited access to MISS spinal technologies, orthopedic spine surgeons reported significantly lower access to operating microscopes versus neurosurgeons (P < 0.01).

Single-level Posterolateral Fusion (PLF) Alone and Posterior Interbody Fusion (PLIF/TLIF) Alone Lead to a Decreased Risk of Short-term Complications Compared to Combined PLF With PLIF/TLIF Procedures: A Matched Analysis

STUDY DESIGN

Retrospective review of a database cohort.

OBJECTIVE

To compare short-term outcome measures and complications between single-level posterolateral fusion (PLF), single-level posterior interbody fusion (PLIF/TLIF), and combined single-level PLF+PLIF/TLIF.

SUMMARY OF BACKGROUND DATA

Both PLF and interbody fusion are well-established procedures for degenerative spinal disease. However, there is lack of consensus as to the ideal surgical approach for specific applications. Additionally, the difference in risk of complications with traditional PLF, interbody fusion with posterior approach, and circumferential fusion is still contested.

METHODS

The ACS NSQIP database was used to identify 24,228 patients who underwent either a single-level PLF, single-level PLIF/TLIF, or combined single-level PLF+PLIF/TLIF between 2014 and 2017. To control for potential confounding variables, exact matching was used to pair individuals from each treatment group based on several factors, including sex, age, body mass index, various comorbidities, and American Society of Anesthesiologists classification. After appropriate matching, the rate of various short-term outcome measures and complications were compared between the three treatment groups.

RESULTS

After exact matching, 13,251 patients were included in the final analysis. The rates of non-home discharge, overall surgical complications, and bleeding requiring transfusion were significantly lower in the PLF group and PLIF/TLIF group relative to the PLF+PLIF/TLIF group (P < 0.001 for all comparisons). The rate of deep venous thrombosis was lower in the PLIF/TLIF group relative to the PLF group (P = 0.006). There were no significant differences in other medical complications, unplanned readmission, reoperation, or return to the OR between any of the treatment groups.

CONCLUSIONS

The combination of single-level PLF+PLIF/TLIF is associated with higher rates of short-term complications relative to either single-level PLF or PLIF/TLIF alone. The associated risks of this therapy should be considered when considering surgical management for lumbar disease.

LEVEL OF EVIDENCE

3.

Risk Factors of Cage Subsidence in Patients Received Minimally Invasive Transforaminal Lumbar Interbody Fusion

STUDY DESIGN

A retrospective cohort study.

OBJECTIVE

To determine the risk factors of cage subsidence in patients undergoing minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) and its correlation with patient-reported outcomes.

SUMMARY OF BACKGROUND DATA

Cage subsidence is among the cage-related complications after TLIF and may lead to poor outcomes. Few studies have addressed the incidence of cage subsidence in MI-TLIF.

METHODS

This retrospective study of a prospectively collected database was conducted from October 2015 to October 2017. All patients received MI-TLIF with a minimum of 2-year follow-up. All levels were separated into the cage subsidence (CS group) and no cage subsidence (non-CS group) groups. Cage subsidence was evaluated using lateral radiographs and defined as more than 2 mm migration of the cage into the endplate of adjacent vertebral body. Patient demographics, perioperative details, and radiographic parameters were recorded. Cage-related parameters were cage height, cage insertion level, and cage position. Cage position was recorded using central point ration (CPR). Patient-reported outcome was analyzed using the Oswestry Disability Index (ODI) questionnaire and Visual Analog Scale (VAS) preoperatively and at 2 years postoperatively.

RESULTS

Ninety-three patients (126 levels) were included. Mean age was 66.5 years with an average follow-up of 36.9 months. Overall incidence of cage subsidence was 34.1%. The CS group had significantly higher body mass index, less bone mineral density (BMD), shorter disc height, and higher CPR than the non-CS group. BMD, disc height, and CPR were significantly negatively correlated with depth of cage subsidence. ODI improvement was significantly lesser in the CS group than in the non-CS group. Fusion rate and complications were unrelated to cage subsidence.

CONCLUSION

The BMD, disc height, and cage position were the most significant risk factors that were negatively correlated with depth of cage subsidence. Placing a TLIF cage anteriorly if possible may reduce the risk of cage subsidence.

LEVEL OF EVIDENCE

3.

Patient Participation With a Mobile Phone Application for Objective Activity Assessment Before and After Spinal Fusion

Background 

Evolution within spine surgery is driven by a surgeon’s desire for expertise and significant improvement in their patients’ quality of life. As surgeons move away from using subjective patient-reported outcome (PRO) surveys, there must be an alternative objective metric in its place. Modern iPhone (Apple Inc., Cupertino, CA) technology can be used to capture daily activity in a simple, non-user biased manner. These health data can be used to analyze objective functional status in conjunction with PRO surveys to measure surgical outcomes.

Methods 

Patients who underwent an awake transforaminal lumbar interbody fusion (TLIF) between 2014 and 2018 at our institution were identified. Patients were consented and instructed to download the application “QS Access” (Quantified Self Labs, San Francisco, CA). Following data collection, we analyzed the demographic information of patients who were reached to gauge participation and feasibility of data exportation.

Results

A total of 177 patients who underwent an awake TLIF at our institution were contacted. Of those who answered, 41 (44.6%) agreed to participate and 51 (55.4%) declined to participate. When comparing those who either participated or declined, there were no significant differences in age (p=0.145), sex (p=0.589), or ethnicity (p=0.686).

Conclusion 

Our pilot study examined the patient participation in the novel usage of Apple "Health" data, queried from "QS Access" (Quantified Self Labs), to objectively measure relative patient functional status surrounding spinal fusion. We demonstrated that a smartphone-based application was mostly well received by our patient cohort and has the potential to be used as an objective operative metric moving forward. 

[Intraoperative and late complications after spinal tumour resection and dorsoventral reconstruction]

BACKGROUND

Spinal tumors are a continuously growing pathology group among the spinal diseases. The often-difficult circumstances increase vulnerability to a wide range of intervention-related complications, which can occur at different times in the course of the disease and must be included in the consideration of the indication.

OBJECTIVES

The aim of the work is to present the wide spectrum of complications in the surgical treatment of spinal tumors, as well as their treatment and prophylaxis through optimal therapy management.

MATERIALS AND METHODS

The article summarizes the current literature.

RESULTS

The literature describes complication rates of 10-67% after metastatic surgery of the spinal column. The most common complications are infections and internal, especially pulmonary, complications. Other relevant complications include surgical positioning/surgical access/instrumentation/mechanical failure, and anesthesiological, neurological, vascular and oncological complications. The socio-economic costs for patients with complications compared to those for patients without complications are twice as high. A special risk situation exists with radical spinal tumor resections. Negative predictors are previous operations, previous irradiation and local recurrences.

CONCLUSIONS

An early, interdisciplinary concept can reduce complications significantly. Due to the planning intensity, surgical expertise and comprehensive structural requirements, treatment in an interdisciplinary tumour centre is necessary.

The Influence of Preoperative Mental Health on PROMIS Physical Function Outcomes Following Minimally Invasive Transforaminal Lumbar Interbody Fusion

STUDY DESIGN

Retrospective.

OBJECTIVE

To demonstrate whether preoperative mental health status can be predictive of postoperative functional outcomes as measured by Patient-Reported Outcome Measurement Information System Physical Function (PROMIS PF) following minimally invasive transforaminal lumbar interbody fusion (MIS TLIF).

SUMMARY OF BACKGROUND DATA

There is a paucity of scientific investigations into the association between preoperative mental health as evaluated by a validated questionnaire such as the Short Form-12 Mental Health Composite Score (SF-12 MCS) and postoperative outcomes following MIS TLIF.

METHODS

Patients undergoing a primary MIS TLIF were retrospectively reviewed and stratified into cohorts based on preoperative SF-12 MCS scores. The Physical Function scores of PROMIS, of which there are other domains including Pain Interference, Sexual Function, and Cognitive Function, were compared between the cohorts. In addition, the improvement in PROMIS scores based on preoperative SF-12 MCS scores following MIS TLIF was analyzed using multivariate linear regression.

RESULTS

One hundred seventy-two patients were included: 85 patients (49.4%) had a preoperative SF-12 MCS score <50 and 87 (50.6%) had a preoperative SF-12 MCS score ≥50. Patients with poorer mental health demonstrated significantly worse PROMIS PF scores preoperatively (33.8 vs. 36.5, P < 0.001), as well as at all postoperative timepoints: 6-weeks (35.1 vs. 38.4, P < 0.001), 3-months (38.9 vs. 42.9, P < 0.001), 6-months (41.4 vs. 45.5, P < 0.001), and 1-year (42.4 vs. 47.6, P < 0.001). However, at the 1-year timepoint, patients with worse mental health reported experiencing significantly less improvement from baseline (postoperative change of 8.6 vs. 11.1, P = 0.002).

CONCLUSION

Patients with worse preoperative mental health not only demonstrated worse preoperative PROMIS PF scores, but also continued to have significantly worse postoperative outcomes. However, the postoperative improvement experienced by patients was similar in the short-term following surgery regardless of preoperative mental health status. Patients with poor mental health experienced significantly less postoperative improvement only at the 1-year timepoint.

LEVEL OF EVIDENCE

3.