Minimally Invasive Transforaminal Lumbar Interbody Fusion Research Articles

65. Subsidence after minimally invasive transforaminal lumbar interbody fusion with expandable cage: Rates and clinical impact

<h3>BACKGROUND CONTEXT</h3> Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) is commonly used to treat lumbar spinal stenosis with degenerative disc disease. Expandable cage technology has been increasingly adopted and has demonstrated successful results, offering a larger footprint and intraoperative height adjustment, enabling more precise dialing in of sagittal alignment and disc height. While many advances have been made, endplate violation and postoperative cage subsidence can still be seen. <h3>PURPOSE</h3> To determine the rate and clinical implications of subsidence after expandable cage use in MI-TLIF. <h3>STUDY DESIGN/SETTING</h3> Retrospective cohort study. <h3>PATIENT SAMPLE</h3> Patients undergoing MI-TLIF for degenerative disc disease using articulating, expandable cages. <h3>OUTCOME MEASURES</h3> Patient-reported outcome measures (PROMs), including the Oswestry Disability Index (ODI), visual analog scale (VAS) for back/leg pain, Short Form-12 (SF-12), and PROMIS physical function (PF). <h3>METHODS</h3> Patients undergoing MI-TLIF for degenerative disc disease using articulating, expandable cages from 2017-2019 were retrospectively studied. AP and lateral radiographs were reviewed and evaluated for the presence or absence of subsidence intraoperatively and at follow-up times including 2 weeks, 6 weeks, 12 weeks, 6 months and 1 year postoperatively. Each of the four corners of the implant was evaluated, and subsidence was determined to have occurred if there was endplate violation ≥3mm at any corner. Patient-reported outcome measures, including the ODI, VAS for back/leg pain, SF-12 and PROMIS PF were recorded at the preoperative and follow-up time points. Fusion was assessed 1-year postoperatively via CT. <h3>RESULTS</h3> A total of 87 patients were included, with mean age 58.3 years (SD,13.4). Of 87 total patients, 13 (14.9%) demonstrated subsidence, with the majority (84.6%) of cases occurring within the first 12 weeks. Patients who had subsidence were older (67.2 vs 56.7 yrs; p=0.009), had lower bone quality (p=0.049), and were more likely to have 2-level surgery compared to those without (p=0.032). On multiple regression analysis, age was the only variable which retained significance when comparing the subsidence and no subsidence groups (p=0.04). There were significant differences in subsidence rate with greater implant height (p=0.013) and smaller width (p=0.026). With the exception of SF-12 PCS at 1-year postoperative, there were no significant differences in any patient-reported outcomes between the 2 groups. The overall fusion rate was 90.5% (57/63 levels) at 1-year postoperative, with no significant difference in fusion rate between the subsidence and no subsidence groups. <h3>CONCLUSIONS</h3> The rate of subsidence after MI-TLIF was 14.9%, with the majority of cases occurring within the first 12 weeks postoperatively. Patients who had subsidence were older with lower bone quality, had cages with greater height and smaller width, and were more likely to have 2-level surgery. With the exception of SF-12 PCS at 1 year, there were no significant differences in any of the PROMs between the groups. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

222. Do grit and self-control impact outcomes following spine surgery: a retrospective analysis

<h3>BACKGROUND CONTEXT</h3> Grit, defined as perseverance and passion for long-term goals, and self-control, defined as the capacity to regulate impulses in the presence of momentarily gratifying temptations or diversion, have been shown to be important predictors for achievement in professional domains. Though grit and self-control have been well-explored in their relationship with achieving professional achievement, the association between these traits and outcomes following surgery has not been explored. <h3>PURPOSE</h3> To assess whether there is an association between grit/self-control and the achievement of minimum clinically important difference (MCID) following elective spine surgery. <h3>STUDY DESIGN/SETTING</h3> Retrospective review of prospectively collected data. <h3>PATIENT SAMPLE</h3> Consecutive patients who underwent primary elective spine surgery and had at least 1 year follow-up were included. The three surgical cohorts were: (1) anterior cervical surgery [anterior cervical discectomy and fusion (ACDF) or cervical disc replacement (CDR)], (2) Minimally invasive lumbar decompression [microdiscectomy or laminectomy (MI-D)], and (3) Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF). <h3>OUTCOME MEASURES</h3> The validated 8-Question Short Grit Scale and the 10-Item Self-Scoring Self-Control Scale were used to assess grit and self-control, respectively. Both surveys are five-point scales, with five signifying the highest score (ie, more grit and self-control). Patient reported outcome measures included NDI for cervical patients and ODI for lumbar patients. Minimum Clinically Important Difference (MCID) values for each type of outcome measure were acquired from established literature. <h3>METHODS</h3> Grit and self-control scores were compared between patients who achieved MCID by a certain time-point and those who did not. The time-points were selected based on when the majority of patients in each cohort had achieved MCID. <h3>RESULTS</h3> Of the 69 patients included, 17 underwent ACDF/CDR, 28 underwent MI-D, and 24 underwent MI-TLIF. The mean grit and self-control scores for the ACDF/CDR cohort were 3.48 + 0.48 and 3.96 + 0.51, respectively. In this cohort, 64.3% of patients achieved MCID in NDI at 6 months. There were no significant differences in grit and self-control scores between patients who achieved MCID in NDI at 6 months postoperatively vs those who did not. The mean grit and self-control scores for the MI-D cohort were 3.96 + 0.57 and 3.82 + 0.61, respectively. In this cohort, 48% patients achieved MCID in ODI at 2 weeks. There were no significant differences in either score between patients who achieved MCID in ODI at 2 weeks postoperatively vs those who did not. The mean grit and self-control scores for the MI-TLIF cohort were 3.95 + 0.61 and 4.07 + 0.55, respectively. In this cohort, 59.1% of patients achieved MCID in ODI at 12 weeks. There were no significant differences in either score between patients who achieved MCID in ODI at 12-weeks vs those who did not. <h3>CONCLUSIONS</h3> Preliminary results show that grit and self-control scores are not associated with achievement of MCID following spine surgery. A larger study will need to be conducted to further evaluate the impact of grit and self-control. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

151. Comparison of opioid consumption patterns of three interbody fusion surgical techniques

<h3>BACKGROUND CONTEXT</h3> Back pain and spine surgery have been major drivers of opioid consumption and spine surgery has been linked to the opioid epidemic. With increased awareness of the opioid crisis, the focus postoperatively has shifted to managing surgical site pain while minimizing narcotic use. Numerous studies have compared clinical outcomes and fusion status of different lumbar interbody fusion techniques; however, there is limited literature evaluating narcotic consumption postoperatively between techniques. The aim of this study was to assess and compare in-house and postoperative opioid consumption among three surgical techniques. <h3>PURPOSE</h3> To examine posterior lumbar fusion surgical techniques and compare opioid consumption across the techniques. <h3>STUDY DESIGN/SETTING</h3> Retrospective review. <h3>PATIENT SAMPLE</h3> Three hundred and three patients who underwent one- or two-level posterior lumbar interbody fusion surgery. <h3>OUTCOME MEASURES</h3> Primary outcome measure was opioid consumption across surgical techniques both while in-patient and after discharge as determined by total morphine equivalent dose (MED). Secondary outcomes included operative time, length of stay, and discharge destination. <h3>Methods</h3> This is a retrospective review of patients who underwent one- or two-level posterior lumbar interbody fusion surgery at a single institution between 2016 and 2020. Patients were stratified by surgical technique: posterior lumbar interbody fusion (PLIF), minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF), and cortical screw (CS) instrumentation with interbody fusion. Age, ASA, BMI, depression, preoperative opioid use, EBL and OR time were recorded and compared across surgical groups using one-way ANOVA and chi-square analysis. Total morphine equivalent dose (MED) was tabulated for both in-house consumption and postoperative prescriptions and was compared across surgical techniques using ANOVA analysis. <h3>Results</h3> A total of 303 patients underwent one- or two-level posterior lumbar interbody fusion between 2016 and 2020. 123 patients underwent cortical screw instrumentation, 96 underwent PLIF and 84 underwent MIS-TLIF. There was a significantly higher percentage of patients who had a history of depression and were on preoperative opioids in the CS group (p=0.001, p=0.002). Patients with CS instrumentation required significantly less narcotics per day while in-house compared to PLIF and MIS-TLIF (MED 80.65 vs 97.85 vs 83.72, p = 0.030). Patients who underwent CS instrumentation received half the number of narcotics compared to PLIF patients after discharge (MED 956.15 vs 2260.89, p = 0.003). <h3>Conclusions</h3> Patients who underwent CS instrumentation required less narcotics postoperatively both while admitted and after discharge. CS instrumentation may be associated with less postoperative pain due to the less invasive approach, however, patient education and prescriber practice also play a role in postoperative narcotic consumption. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Risk factors for polyetheretherketone cage subsidence following minimally invasive transforaminal lumbar interbody fusion.

Interbody cage subsidence is a postoperative complication leading to poor outcomes after minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). This study aimed to identify risk factors of cage subsidence in lumbar spinal diseases after MIS-TLIF using polyetheretherketone (PEEK) cage. In this retrospective cohort study, plain radiographs and three-dimensional computed tomography (3D-CT) performed 12months after MIS-TLIF were evaluated, and the risk of cage subsidence was calculated with odds ratio (OR), confidence interval (CI), and logistic regression analysis. A total of 114 patients (mean age, 65years) and 135 levels were included in this study: 80 (59.3%) with and 55 (40.7%) without cage subsidence. Multifidus atrophy showed the strongest association with PEEK cage subsidence (p < 0.001). Compared to those with normal mass, the odds of PEEK cage subsidence were 76.0 (95% CI: 3.9-1472.9) for severe atrophy. The factors significantly associated with cage subsistence were posterior cage position (OR = 4.2; p = 0.005), cage height ≥ 12mm (OR = 7.6; p = 0.008), use of an autograft mixed with demineralized bone matrix (DBM) (OR = 5.8; p = 0.002), body mass index (BMI) > 27.5kg/m2 (OR = 4.2; p = 0.03), and titanium-coated PEEK (Ti-PEEK) cage-type (OR = 38.4, p = 0.02). In MIS-TLIF with a PEEK cage, the factors associated with an increased risk of cage subsidence were higher BMI, increased severity of multifidus muscle atrophy, Ti-coated PEEK cage-type, cage height ≥ 12mm, use of DBM mixed autograft, and posterior cage position.

Charlson Comorbidity Index: An Inaccurate Predictor of Minimally Invasive Lumbar Spinal Fusion Outcomes.

There is a scarcity of research on the Charlson Comorbidity Index (CCI) and its influence on minimum clinically important difference (MCID) achievement after minimally invasive (MIS) transforaminal lumbar interbody fusion (TLIF). The objective of this study is to detail the association between the CCI and attaining MCID after MIS TLIF. A prospective surgical registry was retrospectively reviewed for spine surgeries between May 2015 and February 2019. Inclusion criteria were primary or revision, 1- or 2-level MIS TLIF procedures. Patients were stratified based on CCI score: 0 points (no comorbidities), 1-2 points (mild CCI), ≥3 points (moderate CCI). Preoperative, intraoperative, and postoperative variables were assessed by subgroup using appropriate statistical analysis. Subgroups were analyzed with linear regression or χ2 tests for continuous or categorical variables, respectively. Subgroup scores, improvement, and MCID achievement were assessed at postoperative timepoints (eg, 6 weeks, 12 weeks, 6 months, and 1 year) for back and leg pain, Oswestry Disability Index (ODI), SF-12 Physical Composite Score (PCS), and Patient-Reported Outcomes Measurement Information System Physical Function (PROMIS PF). A total of 171 patients were included (n = 51 [no comorbidities], n = 73 [mild CCI], and n = 47 [moderate CCI]). Higher CCI patients were older and more likely to be smokers, diabetic, arthritic, hypertensive, or have a malignancy history (P < 0.003). Preoperatively, ODI and PROMIS PF were the only patient-reported outcomes with a significant association by CCI group (P = 0.015 and 0.014). Back pain was the only measure that had a significant association with the CCI subgroup at 1 year for score (P = 0.002) or MCID (P = 0.028). By 1 year, regardless of the number of comorbidities, a similar proportion of patients undergoing MIS TLIF were able to achieve MCID for visual analog scale leg, SF-12 PCS, and PROMIS PF. Patients with higher comorbidities are not likely to experience a significant difference in symptom improvement. Regardless of CCI score, MIS TLIF can have a significant benefit for patients. 4. Text.

Clinical outcome and multifidus muscle changes of transforaminal lumbar interbody fusion

Background: Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) has shown to have smaller skin incision, decreased muscular dissection, and less retraction of the thecal sac, compared to conventional open approach. However, its effects on long term functional outcome and degenerative changes of paraspinal muscles are still obscure. Materials and Methods: We studied 81 patients treated by one team of surgeons at a single institution. In the two level spinal fusion, 18 patients underwent conventional TLIF (C TLIF) and 20 patients underwent MIS TLIF. In three level spinal fusion, 23 patients were treated with C TLIF and 20 patients were treated with MIS TLIF. Clinical outcomes included mean operative times, volume of blood loss, percentage of early ambulation, visual analog scale (VAS), and oswestry disability index (ODI) were analyzed. The change of multifidus muscle was calculated from magnetic resonance imaging (MRI) taken before and 6-month after the operation. Results: Lesser blood loss was noted in the MIS TLIF group compared to the conventional group in two- or three-level circumferential spinal fusion. Early ambulation (within 3 days after operation) was found in the MIS TLIF groups. Analysis of VAS scores at leg area showed no significant differences in improvement between each group at 18 month follow up. The postoperative ODI score was significantly less in the MIS TLIF groups than in the C TLIF groups after 6 month follow up. In three segment spinal fusion, MIS TLIF minimized multifidus muscle atrophy, when compared with C TLIF. Conclusion: MIS TLIF in three level lumbar fusion not only has a better functional recovery but also ameliorates the degenerative change of multifidus muscle.

Combining Expandable Interbody Cage Technology With a Minimally Invasive Technique to Harvest Iliac Crest Autograft Bone to Optimize Fusion Outcomes in Minimally Invasive Transforaminal Lumbar Interbody Fusion Surgery.

This was a retrospective cohort review. The objective of this study was to determine the rate of fusion associated with an expandable cage and iliac crest bone graft in minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) surgery. MI-TLIF is a commonly performed procedure, but challenges inherent in MI-TLIF technique can make achieving an interbody fusion difficult. A retrospective review was performed on consecutive patients treated with an MI-TLIF for degenerative lumbar pathology. Patients that completed patient-reported outcome measures and 1-year computed tomography (CT)-scans for fusion analysis were included. Fusion morphology was analyzed by evaluating CT scans for location of bridging trabecular bone in relation to the cage. Patients with bridging bone were considered fused. Preoperative and postoperative health-related quality of life scores were compared. A Kolmogrov-Smirnoff test was used to determine normality of health-related outcome scores. A Friedman 2-way analysis of variance by ranks with pairwise comparisons to determine statistical significance of differences between the date of a follow-up examination and preoperative examination was done. Of 75 patients evaluated 23 patients were excluded due to loss to follow-up, adjacent segment degeneration, inability to obtain a CT scan, or reoperation for nonfusion related symptoms. Of 61 disk spaces that were included, 55 had bridging bone through the intervertebral cage, resulting in an overall fusion rate of 90.2%. There was a higher rate of fusion at L5-S1 as compared to L4-L5. There was mean improvement in patient-reported outcome measures for Oswestry Disability Index, Short Form-12 Physical Component Score, Visual Analog Scale Back/Leg pain, and Patient-Reported Outcome Measurement Information System Physical Function. There were no complications associated with iliac crest bone graft harvesting. Combining an expandable cage with iliac crest autograft bone harvested through a minimally invasive technique can allow for improved fusion rates without graft-site complications in MI-TLIF surgery.

Comparison of outcomes between indirect decompression of oblique lumbar interbody fusion and MIS-TLIF in one single-level lumbar spondylosis

Minimal invasive spinal fusion has become popular in the last decade. Oblique lumbar interbody fusion (OLIF) is a relatively new surgical technique and could avoid back muscle stripping and posterior complex destruction as in minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). Between December 2016 and September 2018, patients with single level degenerative spondylosis were selected to enroll in this retrospective study. A total of 21 patients that underwent OLIF and 41 patients that received MIS-TLIF were enrolled. OLIF showed significantly less blood loss and shorter surgery time compared to MIS-TLIF (p < 0.05). The improvement in segmental lordosis and coronal balance was significantly more in OLIF group than MIS-TLIF group (p < 0.05). When comparing with MIS-TLIF, OLIF was significantly better in Oswestry Disability Index (ODI) and visual analogue scale for back pain improvement at post-operative 6 months (p < 0.05). Both OLIF and MIS-TLIF are becoming mainstream procedures for lumbar degenerative-related disease, especially for spondylolisthesis. However, the indirect decompression of OLIF has shown to have less perioperative blood loss and shorter surgery time than that of MIS-TLIF. In addition, OLIF gives superior outcome in restoring segmental lordosis and coronal imbalance. While both OLIF and MIS-TLIF provide optimal clinical outcomes, upon comparison between the two techniques, the indirect decompression of OLIF seems to be a superior option in modern days.

Does loss of spondylolisthesis reduction impact clinical and radiographic outcomes after minimally invasive transforaminal lumbar interbody fusion?

Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) is a common operative approach to address degenerative lumbar stenosis and spondylolisthesis which has failed nonoperative care. Compared to open TLIF, MI-TLIF relies to a greater extent on indirect decompression resulting in a heightened awareness of spondylolisthesis reduction among MI surgeons. To what extent intraoperative reduction is achieved as well as the rate and clinical impact of loss or reduction and slip recurrence remain unknown. To determine the rate and clinical impact of slip recurrence after MI-TLIF with expandable cage technology STUDY DESIGN/SETTING: Retrospective Cohort Study PATIENT SAMPLE: Patients undergoing MI-TLIF for degenerative spondylolisthesis using an articulating, expandable cage OUTCOME MEASURES: Patient-reported outcome measures (PROMs), including the Oswestry Disability Index (ODI), visual analog scale (VAS) for back/leg pain, Short Form-12 (SF-12), and PROMIS Physical Function (PF) METHODS: Patients undergoing MI-TLIF for degenerative spondylolisthesis using articulating, expandable cages from 2017 to 2019 were retrospectively studied. Lateral radiographs were reviewed and evaluated for the presence or absence of spondylolisthesis preoperatively, intraoperatively, and at follow-up times including 2 weeks, 6 weeks, 12 weeks, 6 months, and 1 year postoperatively. Spondylolisthesis was measured from the posterior inferior corner of the cephalad vertebra to the posterior superior corner of the caudal vertebra, with any measurement >1 mm classified as spondylolisthesis, and Meyerding grade was noted. Intraoperative reduction was measured, and loss of reduction was defined as >1 mm increase in spondylolisthesis comparing follow-up imaging to intraoperative films. PROMs were recorded at the preoperative and follow-up time points. Fusion was assessed at 1 year postoperatively via CT. A total of 63 patients and 70 levels were included, with mean age 59.8 years (SD,13.8). 19 levels (27.1%) had complete reduction intraoperatively, 40 (57.1%) had partial reduction, and 11 (15.7%) had no reduction. Of the 30 levels with loss of reduction (50.8%), 20 (66.7%) occurred by 2 weeks postoperatively and 28 (93.3%) occurred by 12 weeks postoperatively. At 6 months, there were significant differences between those who had loss of reduction and those who did not in VAS back pain (3.0 vs. 0.9, p=.017) and SF-12 PCS (41.5 vs. 50.0, p=.035), but no differences were found between the groups for any instruments at any other time points. The overall fusion rate was 82.1% (32/39) at 1 year postoperatively. There was no significant difference in fusion rate between the loss of reduction (16/20) and no loss of reduction (20/23) groups. Patients with loss of reduction had no difference in reoperation rate (1/28) compared to those without loss of reduction (2/24). While a majority of patients demonstrated reduction intraoperatively, 51% had loss of reduction, most commonly in the acute postoperative period. There were few differences in PROMs between patients who had loss of reduction and those who did not, suggesting that radiographic loss of reduction after MI-TLIF in the setting of degenerative spondylolisthesis may not be clinically meaningful.

Endoscopic Lumbar Interbody Fusion and Minimally Invasive Transforaminal Lumbar Interbody Fusion for the Treatment of Lumbar Degenerative Diseases: A Systematic Review and Meta-Analysis

To compare clinical efficacy and safety of endoscopic lumbar interbody fusion (Endo-LIF) and minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) in treatment of lumbar degenerative diseases. A literature search was performed using PubMed, Embase, Web of Science, and Cochrane Library databases. Studies published up to November 15, 2020, that compared Endo-LIF with MIS-TLIF for treating lumbar degenerative diseases were retrieved. Data were extracted according to predefined clinical outcome measures. Primary outcomes were preoperative and postoperative visual analog scale for leg and back pain and Oswestry Disability Index scores. Secondary outcomes were operative time and intraoperative blood loss; length of hospitalization; and complication, reoperation, and fusion rates. Data analysis was conducted with statistical software. The meta-analysis included 6 studies comprising 480 patients. Results of the merged analysis revealed similar complication, reoperation, and fusion rates and preoperative and postoperative visual analog scale for leg and back pain and Oswestry Disability Index scores (P > 0.05) for Endo-LIF and MIS-TLIF. Nevertheless, with the exception of longer operative time (P < 0.05), Endo-LIF compared favorably with MIS-TLIF, with less intraoperative blood loss, shorter hospital stay (P < 0.05), and better long-term functional outcome. Based on the evidence provided by this study, there is no significant difference in clinical efficacy and safety between Endo-LIF and MIS-TLIF in the treatment of lumbar degenerative diseases. Although Endo-LIF has a longer operative time, it has the advantages of less tissue trauma and rapid recovery after operation.

Surgical Outcomes of Minimally Invasive Transforaminal Lumbar Interbody Fusion for Highly Migrated Lumbar Disc Herniation.

ObjectiveTo describe minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) for highly migrated lumbar disc herniation (LDH) and assess its clinical outcomes.Patients and MethodsThis research retrospectively assessed 25 patients who were diagnosed with one-segmental highly migrated LDH and underwent MIS-TLIF in Peking University First Hospital from June 2015 to September 2019. Demographic data, perioperative parameters, complications, recurrence, and surgical outcomes were assessed.ResultsTwelve males and 13 females, with a mean age of 56.68 years old, were involved and the follow-up period was at least one year. The mean operation time was 222.16 minutes, the mean intraoperative hemorrhage was 250.00 mL, and the mean post-operative hospitalization was 5.76 days. The improvements in visual analog scale (VAS) and Oswestry disability index (ODI) were statistically significant. In addition, based on the MacNab criteria, 22 patients (88.0%) acquired satisfactory (good or excellent) results. One patient underwent post-operative epidural hematoma and recovered after evacuation of the hematoma. No recurrence was found.ConclusionMIS-TLIF is safe and effective and it can provide satisfactory clinical outcomes for highly migrated LDH.

"Pin Method" for Endoscopic Lumbar Interbody Fusion.

Endoscopic lumbar interbody fusion using a cage can have a similar fusion rate as minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) or open lumbar interbody fusion. Direct visual control during cage insertion is the key to prevent neural structure incarceration in endoscopic lumbar interbody fusion. Creating a track with any kind of retractor or cannula for cage insertion under fluoroscopic guidance is not safe enough, because the retractor and cannula can create many blind spots and can displace during cage insertion. The pin method utilizes two flexible metallic guide pins inserted from the skin incision through the annulotomy site into the disk space until the anterior longitudinal ligament is reached under direct endoscopic monitoring. The two guide pins could be oriented parallel or perpendicular or even reduce to one or increase to many as needed to serve as a sliding track and a see-through barrier to prevent neural incarceration. Two cases of L4/L5 grade 2 spondylolisthesis with neurogenic claudication were treated with endoscopic lumbar interbody fusion with 1-year follow-up, and the visual analog scale (VAS) score, Oswestry Disability Index (ODI) score, EuroQol five-dimensional questionnaire (EQ-5D, %) score, and modified Macnab score all improved greatly in both. The author developed an original, cheap, accessible, and safe method called the "pin method," which can be used in both full-endoscopic and biportal surgery and can apply to various approaches and has no limitation on the size and shape of the cage.

Operative time and learning curve between fluoroscopy-based instrument tracking and robot-assisted instrumentation for patients undergoing minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF)

IntroductionInstrument-navigation modalities including CT-guided and robot-assisted methods claim both efficacy and accuracy when applied to spine surgery, yet often increase setup and operating times which can translate to increased costs. To see the impact of different technologies on surgical efficiency, we studied the impact of a single surgeon’s experience with a multitude of instrument navigational technologies. MethodsConsecutive patients undergoing minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) were analyzed. Consecutive cases were done with assistance of a robot (Mazor, Medtronic, Minneapolis, MN), with the assistance of fluoroscopic instrument-tracking (TrackX, North Carolina, USA), or fluoroscopy alone without adjunctive navigation in consecutive blocks of time. The cases done without assistance were used to normalize for number of interbody implants and decompressions performed as well as hardware removal if needed. Age, body mass index (BMI), sex, operative levels, laminectomy, need for hardware removal, and total operative time were recorded. ResultsA total of 119 cases (74 conventional, 13 robot-assisted, 32 instrument-tracking) were included in analysis. There were no significant differences in age, sex, or BMI between modalities. Average total operative time for robot-assisted, and instrument-tracking-assisted cases was 175.46 ± 46.86 min 119.63 ± 34.33 min, respectively, for each level (p < 0.05 across each group). After normalization against operative times from similar cases performed with conventional fluoroscopy, robotic-navigation added an average of 42.25 ± 28.35 min while use of instrument-tracking saved an average of 13.88 ± 38.69 min. There was no learning curve seen using robotic navigation, as operative times remained consistently longer than similar cases using conventional fluoroscopy and showed no sign of improvement over time. Cases using instrument-tracking were initially slower but trended downwards through approximately 11 patients, at which point operative times were consistently quicker (R2 = 0.39). None of the assisted cases were abandoned in favor of standard fluoroscopy or required hardware revision. ConclusionEnabling technology can have a significant impact on surgical efficiency. Compared to MIS-TLIFs performed with standard fluoroscopy, those done with robotic-assistance consistently negatively impacted operative times while instrument-tracking was associated with a short learning curve and in the majority of cases studied showed improved operative times.

Impact of Advanced Age on Postoperative Outcomes Following Transforaminal Lumbar Interbody Fusion.

Age 65 years or older is considered a risk factor for worse outcomes after transforaminal lumbar interbody fusion (TLIF). However, few studies have differentiated this cohort from younger patients. This study compares postoperative outcomes among patients 65 years or older of age with a younger cohort after minimally invasive (MIS) TLIF. A database was reviewed for adults undergoing primary, elective, single-level MIS TLIF procedures for degenerative pathology from 2008 to 2019. Outcomes included visual analogue scale (VAS) for back and leg, Oswestry Disability Index (ODI), Short Form 12-Item physical component score (SF-12 PCS), and Patient-Reported Outcome Measurement Information System physical function. Outcomes were collected preoperatively and at 6 weeks, 12 weeks, 6 months, and 1 year postoperatively. Patients were categorized as ≥75 years, 65 to 74 years, or <65 years of age. Propensity score matching was performed, and outcome improvement and minimum clinically important difference (MCID) achievement were evaluated by group. MCID achievement was calculated using previously established values. Our cohort included 51 patients aged younger than 65 years, 47 patients aged 65 to 74 years, and 16 patients aged 75 years or older. No significant perioperative differences or complications existed between groups. The 65- to 74-year group improved in VAS back, leg, and ODI from 6 weeks to 1 year (all P < 0.001) and SF-12 PCS at 12 weeks to 1 year (all P < 0.005). VAS back, ODI, and SF-12 PCS differed between groups preoperatively (P < 0.050), and VAS back and ODI varied at 6 weeks (P < 0.01). VAS leg differed between groups at 12 weeks and SF-12 PCS at 1 year (both P < 0.050). MCID achievement was similar between groups except for VAS leg at 6 weeks (P = 0.038) and 12 weeks (P = 0.023). Patients 65 years or older of age markedly improved from baseline, similarly to younger patients. Postoperative outcome scores and MCID achievement demonstrated differences between groups at intermittent timepoints. With appropriate selection criteria, patient age may not act as a notable risk factor for successful MIS TLIF procedures.

Decompression of Lumbar Central Spinal Canal Stenosis Following Minimally Invasive Transforaminal Lumbar Interbody Fusion.

This was a retrospective clinical series. The objective of this study was to evaluate radiologic changes in central spinal canal dimensions following minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) with placement of a static or an expandable interbody device. MIS-TLIF is used to treat lumbar degenerative diseases and low-grade spondylolisthesis. MIS-TLIF enables direct and indirect decompression of lumbar spinal stenosis, with patients experiencing relief from radiculopathy and neurogenic claudication. However, the effects of MIS-TLIF on the central spinal canal are not well-characterized. We identified patients who underwent MIS-TLIF for degenerative lumbar spondylolisthesis and concurrent moderate to severe spinal stenosis. We selected patients who had both preoperative and postoperative magnetic resonance imaging (MRI) and upright lateral radiographs of the lumbar spine. Measurements on axial T2-weighted MRI scans include anteroposterior and transverse dimensions of the dural sac and osseous spinal canal. Measurements on radiographs include disk height, neural foraminal height, segmental lordosis, and spondylolisthesis. We made pairwise comparisons between each of the central canal dimensions and lumbar sagittal segmental radiologic outcome measures relative to their corresponding preoperative values. Correlation coefficients were used to quantify the association between changes in lumbar sagittal segmental parameters relative to changes in radiologic outcomes of central canal dimensions. Statistical analysis was performed for "all patients" and further stratified by interbody device subgroups (static and expandable). Fifty-one patients (age 60.4 y, 68.6% female) who underwent MIS-TLIF at 55 levels (65.5% at L4-L5) were included in the analysis. Expandable interbody devices were used in 45/55 (81.8%) levels. Mean duration from surgery to postoperative MRI scan was 16.5 months (SD 11.9). MIS-TLIF was associated with significant improvements in dural sac dimensions (anteroposterior +0.31 cm, transverse +0.38 cm) and osseous spinal canal dimensions (anteroposterior +0.16 cm, transverse +0.32 cm). Sagittal lumbar segmental parameters of disk height (+0.56 cm), neural foraminal height (+0.35 cm), segmental lordosis (+4.26 degrees), and spondylolisthesis (-7.5%) were also improved following MIS-TLIF. We did not find meaningful associations between the changes in central canal dimensions relative to the corresponding changes in any of the sagittal lumbar segmental parameters. Stratified analysis by interbody device type (static and expandable) revealed similar within-group changes as in the overall cohort and minimal between-group differences. MIS-TLIF is associated with radiologic decompression of neural foraminal and central spinal canal stenosis. The mechanism for neural foraminal and central canal decompression is likely driven by a combination of direct and indirect corrective techniques.

Does the Predominant Pain Location Influence Functional Outcomes, Satisfaction, and Return to Work After Minimally Invasive Transforaminal Lumbar Interbody Fusion For Degenerative Spondylolisthesis?

Retrospective review of prospectively collected data. The objective of this study was to determine how different combinations of preoperative back pain (BP) and leg pain (LP) may influence functional outcomes, patient satisfaction and return to work (RTW) in patients undergoing minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) for degenerative spondylolisthesis. Surgical decision-making is often based on the traditional assumption that the predominance of lower extremity symptoms is a stronger indication for lumbar spine surgery. Surprisingly, there is a paucity of literature supporting this notion and the isolated impact of the preoperative pattern of pain on outcome remains unclear. Prospectively collected data for patients who underwent primary MIS-TLIF for degenerative spondylolisthesis were reviewed. Patients were categorized into 3 groups depending on predominant pain location: LP predominant (LP>BP), back pain predominant [(BPP); BP>LP] and equal pain predominance (BP=LP). Patients were prospectively followed for at least 2 years. In total, 781 patients were included: 33.4% LP predominant, 28.7% BPP and 37.9% equal pain predominance cases. The BPP group was significantly younger (P=0.005) and showed a trend towards poorer baseline Short-Form-36 Mental Component Summary (P=0.069). After adjusting for baseline differences, there was no significant difference in BP, LP, Oswestry Disability Index (ODI), SF-36 Physical Component Summary, and SF-36 Mental Component Summary between the 3 groups at all time points (P>0.05) except for poorer 1-month ODI in the BPP group (P=0.010). The rate of minimal clinically important difference attainment for ODI and SF-36 Physical Component Summary, satisfaction, expectation fulfilment and RTW were also similar (P>0.05). The functional outcomes, quality of life and satisfaction after MIS-TLIF were similar, regardless of the predominant pain location. Equal proportions of patients achieved the minimal clinically important difference and RTW. In the context of proper indications, these results suggest that MIS-TLIF can be equally effective for patients with varying combinations of BP or LP. Level III-nonrandomized cohort study.

Minimally Invasive Transforaminal Lumbar Interbody Fusion for 2-Level Degenerative Lumbar Disease in Patients With Osteoporosis: Long-Term Clinical and Radiographic Outcomes.

Spine fusion surgery in osteoporosis remains controversial because it is related to a high incidence of osteoporosis-related complications, such as cage nonfusion, pedicle screw loosening, and new vertebral compression fractures (VCFs). To treat 2-level degenerative lumbar disease in osteoporosis patients as an effective and safe surgical treatment for long-term results using minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). We retrospectively assessed 12 patients with osteoporosis who underwent MIS-TLIF on L4 and L5 between 2011 and 2012 to assess the clinical and radiographic results for 2-level lumbar degenerative spine disease. All patients were followed-up for at least 2 yr after surgery and assessed by using X-ray. Basic patient data and clinical and radiological outcomes were collected and analyzed. Of all 12 patients, 11/12 (91.6%) and 1/12 (8.3%) demonstrated cage fusion and cage subsidence, respectively. Pedicle screw loosening was found in 1/12 (8.3%) patients. The P-values calculated using the F-test for changes in the vertebral body height pre- and postoperation in L3, L4, and L5 were .69, .87, and .39, respectively. The data revealed no significant variants of new VCFs. MIS-TLIF provided a high cage fusion rate and low pedicle screw loosening rate in patients with osteoporosis with 2-level degenerative spine disease. Furthermore, no new VCFs were found in long-term follow-up. The clinical outcomes also demonstrated no significant difference compared with traditional open spine fusion surgery. Therefore, MIS-TLIF could be considered an effective and safe surgical treatment modality for 2-level degenerative spine disease in osteoporosis.

Analysis of lumbosacral sagittal balance parameter variation in minimally invasive transforaminal lumbar interbody fusion with real-time 3D navigation techniques

To explore the dynamic changes of lumbosacral sagittal parameters after real-time three-dimensional navigation assisted minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) and traditional open TLIF for treatment of lumbar degenerative disease. The clinical data of 61 patients with lumbar degenerative disease underwent single-segment surgery from September 2017 to September 2019 were retrospectively analyzed. Among them, 31 cases underwent MIS-TLIF with 3D navigation techniques (MIS-TLIF group) and another 30 cases underwent conventional open TLIF (traditional open TLIF group). The basic information, operative time and intraoperative blood loss were collected. The sagittal radiologic parameters were measured before surgery and 3 months after surgery, including lumbar lordosis (LL), segmental lordosis (SL), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), anterior disc height (ADH), posterior disc height(PDH).And the average disc height(DH) and pelvic incidence to lumbar lordosis mismatch (PI-LL) were calculated. Operative time and intraoperative blood loss in MIS-TLIF group were significantly less than in traditional open TLIF group(P<0.05). In MIS-TLIF group, LL, SL, PI-LL, and DH were significantly improved at 3 months after surgery (P<0.05), while PI, PT, and SS were not statistically different from those before surgery (P>0.05). LL, PI-LL, and DH of patients in the traditional open TLIF group were significantly improved at 3 months after surgery (P<0.05), while the PI, PT, SS, and SL were not statistically different from those before surgery (P>0.05). LL change showed a significant correlation with SL change (r= 0.433, P<0.001). Change in SL closely correlated to change in ADH (r=0.621, P<0.05) and PDH(r=0.527, P<0.05). Real-time navigation-assisted MIS-TLIF and traditional open TLIF can recover DH in a short term for lumbar degenerative diseases, improve LL and PI-LL, and make the arrangement of the sagittal plane of the lumbosacral region more coordinated after surgery. But only the navigation assisted MIS -TLIF can significantly improve SL. Compared with traditional open TLIF, real-time navigation assisted MIS-TLIF in the treatment of degenerative lumbar diseases has the advantages of short operation time and less intraoperative bleeding.

The Effect of Morbid Obesity on Complications, Readmission, and Patient-Reported Outcomes Following Minimally Invasive Transforaminal Lumbar Interbody Fusion: An Inverse Propensity Score Weighted Analysis.

Retrospective review of prospectively collected data at a single institution. To compare perioperative and clinical outcomes in morbidly obese patients who underwent minimally invasive transforaminal lumbar interbody fusion (MiTLIF). Obesity remains a serious public health concern. Obese patients who undergo lumbar fusion have historically thought to be at higher risk for complications and fare worse regarding quality-of-life outcomes. However, recent literature may demonstrate comparable risk and outcomes in obese patients. An increasing number of patients are categorized as morbidly obese (body mass index [BMI] ≥ 40 kg/m2). Perioperative and patient-reported outcomes (PROs) are lacking in this patient population. The authors retrospectively reviewed a prospectively collected database of all morbidly obese and non-obese patients that underwent MiTLIF between 2015 and 2018 for degenerative conditions who had minimum 1-year follow-up for outcome assessment. An inverse propensity/probability of treatment weighting was utilized to create a synthetic weighted sample in which covariates were independent of obesity designation to adjust for imbalance between groups. Generalized estimating equations (GEE) was used to estimate the association of morbid obesity and complications and 1-year PROs. A total of 292 patients were analyzed with 234 non-obese patients and 58 morbidly obese patients. Multivariate analysis failed to demonstrate any association between morbid obesity and achieving minimal clinically important difference (MCID) for Oswestry disability index (ODI), visual analog scale (VAS), or short form-12 (SF-12) physical component score. However, morbid obesity was associated with significant decrease in odds of achieving MCID for SF-12 mental component score (P = 0.001). Increased surgery duration was significantly associated with morbid obesity (P = 0.001). Morbid obesity exhibited no statistically significant association with postoperative complications, readmission, pseudarthrosis, or adjacent segment disease (ASD). Morbidly obese patients who undergo MiTLIF can achieve meaningful clinical improvement comparable to nonobese patients. Morbid obesity was associated with longer surgical times but was not associated with postoperative complications, readmission, or ASD.Level of Evidence: 3.

How accurate is fluoroscopy-guided percutaneous pedicle screw placement in minimally invasive TLIF?

IntroductionThe accuracy of pedicle screws placement has been the subject of many studies and varied rates of screw malposition have been reported. This study evaluates the placement of pedicle screw inserted percutaneously, guided by intraoperative 2D fluoroscopy, in minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). MethodsRetrospective study of patients who underwent MIS-TLIF from 2007 to 2016 in a single center, for degenerative pathology. All patients had a follow-up lumbar CT scan one year after surgery to evaluate pedicle violation, location and degree. Gertzbein classification was used for description of the degree of violation. ResultsThis study included 241 patients, with a mean age of 57 years (SD 11.69). A total of 1045 screws were evaluated. Most patients were fused at L4-L5 or L5-S1 levels. The total rate of pedicle walls’ violation was 13.97%, however only 4.31% of the screws presented violations exceeding 2 mm. Only 5 patients were reoperated because of complaints related to screw malposition (0.48% of all screws). There was a trend for an increased rate of pedicle violation for upper lumbar pedicles (p < 0.001). For S1 screws, violations were more common on left pedicle screws (17.89% vs 7.53%, p = 0.03), with an Odds Ratio of 2.68 (95% CI: 1.07–6.80). ConclusionPercutaneous pedicle screw insertion guided by intraoperative 2 D fluoroscopy in MIS-TLIF is safe and most of pedicle violations seem to be minor and without clinical consequences. In S1 screws, the surgeon’s side was more prone to violation.