Minimally invasive transforaminal lumbar interbody fusion versus open transforaminal lumbar interbody fusion: a technical description and review of the literature

Higher Accuracy and Better Clinical Outcomes in Navigated Thoraco-Lumbar Pedicle Screw Fixation Versus Conventional Techniques : A Systematic Review and Meta-Analysis

STUDY DESIGN

A systematic review and meta-analysis.

OBJECTIVE

This study aims to compare pedicle screw accuracy, clinical outcomes, and complications between navigated and conventional techniques.

SUMMARY OF BACKGROUND DATA

In the last decades, intraoperative navigation has been introduced in spinal surgery to prevent risks and complications.

MATERIALS AND METHODS

The search was executed on Cochrane Central Library, PubMed, and Scopus on April 30, 2023. Randomized controlled trials, prospective and retrospective studies that compared pedicle screw accuracy in the thoracic-lumbar-sacral segments, blood loss, operative time, hospital stay, intraoperative and postoperative revision of screws, neurological and systemic complications, Visual Analogue Scale (VAS), and Oswestry Disability Index (ODI) between navigated and freehand or fluoroscopy-assisted techniques were included in this study. The meta-analysis was performed using Review Manager software. Clinical outcomes were assessed as continuous outcomes with mean difference, while pedicle screw accuracy and complications were assessed as dichotomous outcomes with odds ratio, all with 95% CIs. The statistical significance of the results was fixed at P <0.05.

RESULTS

This meta-analysis included 30 studies for a total of 17,911 patients and 24,600 pedicle screws. Statistically significant results in favor of the navigated technique were observed for the accuracy of pedicle screws ( P =0.0001), hospital stay ( P =0.0002), blood loss ( P <0.0001), postoperative revision of pedicle screws ( P <0.00001), and systemic complications ( P =0.0008). In particular, the positioning of the screws was clinically acceptable in 96.2% of the navigated group and 94.2% with traditional techniques. No significant differences were found in VAS, ODI, and operative time between the two groups.

CONCLUSION

Navigated pedicle screw fixation has been demonstrated to be a safe and effective technique with high improvement in clinical outcomes and accuracy in patients undergoing spinal fusion compared with conventional techniques.

LEVEL OF EVIDENCE

Level III.

Comparison of mMO-TLIF via Midline Incision Versus MIS-TLIF via Wiltse Approach in Lumbar Degenerative Disease

Background

To compare the clinical and radiological outcomes of modified mini-open transforaminal lumbar interbody fusion (mMO-TLIF) via posterior midline incision for "targeted limited dissection" versus minimal invasive transforaminal lumbar interbody fusion (MIS-TLIF) via Wiltse approach in lumbar degenerative diseases.

Methods

A total of 60 consecutive patients in our center from January 2019 to March 2020 were enrolled, including 30 patients who were treated with mMO-TLIF via posterior midline incision and 30 treated with MIS-TLIF through the Wiltse approach. Perioperative parameters were recorded. The questionnaires of Oswestry Disability Index (ODI) and Visual Analogue Score (VAS) were conducted before the operation and after the operation (3 days, 1 week, and 2 years). CT and MRI radiological outcomes were evaluated before the operation and at a 2-year follow-up.

Results

There were no significant differences in the general data, gender, age, and BMI between the two groups. All patients were successfully operated without intraoperative complications. There were significant differences between the two groups in the operation time (p < 0.001) and intraoperative bleeding (p < 0.05). There was no difference in ODI and VAS scores between groups pre- and post-operatively, but they were both significantly improved compared to those before the operation (p < 0.01). At a 2-year follow-up, the paraspinal muscle atrophy and fat infiltration were increased comparing to pre-operation, but the difference was also not statistically significant (p > 0.05). In addition, both the two groups' fusion rates were more than 90% at a 2-year follow-up, however, no difference was detected between the two groups.

Conclusion

mMO-TLIF via midline incision for "targeted limited dissection" could achieve similar clinical and radiological outcomes as MIS-TLIF for lumbar degenerative disease.

Navigation-Guided C-arm-Free Minimally Invasive Transforaminal Lumbar Interbody Fusion: A Comparative Study of Cage Orientation and Screw Insertion Accuracy Against the Conventional C-arm-Assisted Technique

BACKGROUND

Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) is a widely utilized technique in spine surgery. This study compares the efficacy and safety of MIS-TLIF performed with traditional C-arm fluoroscopy and C-arm-free O-arm navigation. To the best of our knowledge, our study is the first to compare cage positioning between C-arm-free and C-arm techniques for MIS- TLIF.

METHODS

A retrospective, comparative analysis was conducted on 43 patients undergoing MIS-TLIF. The group was divided based on the utilization of C-arm fluoroscopy or C-arm-free O-arm navigation. Key parameters analyzed included cage orientation, screw insertion accuracy, operative efficiency, and postoperative recovery. Radiographic measurements were used to assess surgical precision and perioperative complications were documented.

RESULTS

The study encompassed 43 patients, with no significant differences in demographic characteristics between the two groups. Surgical time and blood loss were comparable between C-arm-free and C-arm groups. O-arm navigation significantly reduced pedicle screw misplacement (p=0.024). Cage positioning differed between groups (p=0.0063): O-arm cages were mostly mid-center, while C-arm cages were more anterior-center. Such differences in the cage location did not cause any impact on clinical outcome. No significant differences were observed in postoperative complications (screw loosenings, dural tears, surgical site infections) between groups. The Oswestry Disability Index scores at the final follow-up showed no significant difference between the O-arm and C-arm groups, indicating similar levels of postoperative disability.

CONCLUSION

Despite the clinically insignificant difference in cage placement between C-arm-free and C-arm dependent, C-arm-free MIS-TLIF significantly improves screw placement accuracy and reduces radiation exposure to operating stuff. This suggests its potential as a valuable tool for safer and more precise spinal fusion surgery.

MIS removal of extraforaminal lumbar spine schwannoma using MAS-TLIF retractor: technical note

BACKGROUND

To report the use of Nuvasive MAS-TLIF retractor for the removal of lumbar spine schwannomas.

METHODS

A 47-year-old man with 1-year history of back pain with progressive left sciatica underwent surgical resection of a left extraforaminal lumbar schwannoma (type IV according to Eden's classification) using the MAS-TLIF retractor.

RESULTS

The patient completely recovered from the preoperative symptoms and was discharged three days after surgery. The MRI acquired 6 months postoperatively showed complete tumour removal, with no signs of instability. The MAS-TLIF retractor allows for an optimal paraspinal tissues retraction, improving the area of exposure and the manoeuverability angle. Moreover, the stability of the retraction is guaranteed by the positioning of the two transpedicular screws. Spinal fusion is not necessary because the posterior tension band is not jeopardised.

CONCLUSIONS

MAS-TLIF retractor allows for a minimally invasive and safe surgical removal of LSS maximising surgical exposure and avoiding spinal fusion.

Comparative Outcome Data Using Different Techniques for Posterior Lumbar Fusion: A Large Single-Center Study

STUDY DESIGN

Retrospective single-center study.

PURPOSE

This study aims to evaluate perioperative and intermediate-term clinical outcomes of patients undergoing different lumbar fusion techniques.

OVERVIEW OF LITERATURE

Various open and minimally invasive techniques for lumbar fusion are available, but previous studies comparing lumbar fusion techniques have heterogeneous data, making interpretation challenging.

METHODS

Between 2011 and 2018, data from 447 consecutive patients undergoing one/two-level lumbar fusion were analyzed. Posterior lumbar interbody fusion (PLIF) with bilateral muscle strip or Wiltse approach, open transforaminal lumbar interbody fusion (TLIF) and minimally invasive TLIF, and posterolateral fusion only were among the surgical techniques used. Core outcomes measure index (COMI) questionnaires were distributed before surgery and at 3 months, 1 year, and 2 years postoperatively to establish patient selfreported outcome measures. Demographic data (age, gender, and body mass index [BMI]) for each patient were also collected in addition to surgical indication, previous operative history, perioperative outcomes, and complications, and whether later revision surgery was required. Pearson's chi-square test, Kruskal-Wallis test, repeated measure mixed-effects models, and ordinal logistic regression were used for statistical analysis.

RESULTS

Postoperative COMI scores improved across all procedures compared with pre-surgery (p<0.001). There was no significant difference between different postoperative COMI scores. Significant predictors of higher postoperative COMI score included higher pretreatment COMI score (p≤0.001), previous surgery (p≤0.04), younger age (p≤0.05), higher BMI (p≤0.005), and the indications of lytic spondylolisthesis (p=0.02) and degenerative disc disease (p<0.001). Patients undergoing minimally invasive TLIF had a significantly shorter post-surgery stay than patients undergoing open PLIF (Kruskal-Wallis test, p=0.03).

CONCLUSIONS

At 2 years postoperatively, there was no significant difference in clinical outcomes between open and minimally invasive techniques. These findings suggest that the main determinant of surgical approach should be surgeon preference and training.

Expandable versus static cages in unilateral biportal endoscopy lumbar interbody fusion (ULIF) for treating degenerative lumbar spondylolisthesis (DLS): comparison of clinical and radiological results

BACKGROUND

In recent years, early rehabilitation after spinal fusion and the recovery of physiological curvature have attracted much attention. Therefore, expandable cages have entered the field of vision of scientists. The goal of the current study was to compare the clinical and radiological results of unilateral portal endoscopic lumbar interbody fusion (ULIF) in the treatment of degenerative lumbar spondylolisthesis (DLS) with expandable versus static cages.

METHODS

We retrospectively analysed patients who received ULIF treatment for DLS from May 2019 to February 2021. Patients were categorized by cage type (static vs. expandable), and the main study was the preop and postop clinical and radiological index changes of the patients.

RESULTS

Eighty-four patients were included (38 in the static cages group; 46 in the expandable cages group). There was no difference in the preop results between the two groups. The VAS scores for low back and leg pain and ODI scores in the expandable cages group 7 d postop were significantly superior to those in the static cages group (P < 0.05), and the segmental angle and PDH in the expandable cages group postop were significantly higher than those in the static cages group (P < 0.05). The fusions at 6 m postop in the expandable cages group were superior to those in the Static Cages group (P < 0.05).

CONCLUSIONS

The results of this study showed that compared with the stable cage group, the expandable cage group had unique advantages in restoring the physiological curvature of the lumbar spine, increasing the fusion rate, and relieving pain in the early postoperative period. ULIF can be used to treat single-segment, mild lumbar spondylolisthesis patients using expandable cages instead of static cages.

Minimally Invasive Instrumentation of the Cervical Spine: Past, Present, and Future

Posterior cervical instrumentation and fusion procedures are becoming more and more common with the aging population and rising numbers of multisegmental and revision procedures. The instrumentation of the cervical spine has so far been performed almost exclusively via open approaches. Over the past two decades, minimally invasive surgery (MIS) techniques have gained increasing popularity. To date, only a few attempts to instrument the cervical spine in a minimally invasive fashion have been reported. The following article, after a detailed review of the currently available literature, overviews MIS in dorsal cervical instrumentation and past, present and future techniques, and it discusses the current limitations. Nevertheless, and because of the multiple advantages of MIS instrumentation, a lot of work remains to be carried out to fully establish MIS procedures for posterior cervical instrumentation.

Cirq Robotic Assistance for Thoracolumbar Pedicle Screw Placement: Overcoming the Disadvantages of Minimally Invasive Spine Surgery

INTRODUCTION

Various minimally invasive spine surgery (MISS) techniques have been developed with the goal of reducing approach-related soft-tissue trauma and its associated complications. However, there is still a debate on some of the potential drawbacks of MISS techniques, such as their longer operating times and increased intraoperative radiation. A solution to these disadvantages could be the implementation of new technologies, such as computer-assisted navigation (CAN) and surgical robotics. We compare the standard fluoroscopy MISS technique with our experience with time per screw and X-ray exposure for pedicle screw placement using the Brainlab Cirq passive robotic arm assistance coupled with the Brainlab Curve navigation system.

METHODS

In the Cirq robot-assisted group (Group I), 109 screws were placed in 24 prospectively analyzed patients. In the fluoroscopy-guided group, 108 screws inserted into 20 consecutive patients were analyzed retrospectively (Group II). The duration of surgery, the time to place one screw, the X-ray exposition, and the pedicle screw accuracy for each patient were recorded and reviewed.

RESULTS

In total, 217 screws were analyzed. The treated levels ranged from T10 to S1. In Group I, 104 screws were grade A (95.4%) and five were grade B (4.6%). In Group II, 96 screws were grade A (88.89%); ten were grade B (9.26%); one was grade C (0.93%), and one was grade D (0.93%). While the screws placed by using the Cirq system were more accurate overall, there was no statistical significance when the two groups were compared, p = 0.3724. There was no significant difference in radiation exposure between the two groups, p = 0.5482; however the radiation exposure for the surgeon was very limited with the Cirq system. There was a significant reduction in the operation length (p = 0.0183) and the time per screw (p < 0.0001) for Group I.

CONCLUSIONS

The CAN systems and emerging robotic platforms have the potential to diminish the main disadvantages of MISS techniques-longer operation times and X-ray exposure, at least for the surgical team.

Clinical Effect of Minimally Invasive Microendoscopic-Assisted Transforaminal Lumbar Interbody Fusion for Single-Level Lumbar Disc Herniation

OBJECTIVE

This retrospective study aimed to compare the clinical and radiological outcomes of transforaminal lumbar interbody fusion (TLIF) through the Wiltse approach (W-TLIF) vs minimally invasive microendoscopy-assisted transforaminal lumbar interbody fusion (ME-TLIF) in single-segment lumbar disc herniation (LDH).

METHODS

A retrospective study was conducted to study the differences in specific clinical outcomes between single-segment LDH patients receiving W-TLIF and ME-TLIF. Single-segment LDH patients admitted to the Fujian Medical University Union Hospital from March 2015 to June 2018 were included. All the participants were divided into the ME-TLIF group or the W-TLIF group according to their TLIF surgery types. Demographic characteristics, the visual analog score (VAS), Oswestry Disability Index (ODI), Japanese Orthopaedic Association (JOA) scale, blood loss volume, postoperative drainage, ambulated time, initial postoperative back pain, hospitalization duration, expenses, and improvement rates of patients in the two groups were collected for analysis. Radiographic fusion was ultimately assessed via the Bridwell interbody fusion grading system. All selected patients with TLIF were followed up for 1 year.

RESULTS

Fifty-seven patients were selected, with 26 in the ME-TLIF group and 31 in the W-TLIF group, both of whom were followed up for 1 year. The mean age of the included patients was 53.75 ± 9.313 years, and the sex ratio was indiscrimination. There was no significant difference in demographic data or operating time between the two groups prior to surgery. The blood loss volume (ME-TLIF: 228.5 vs W-TLIF: 681.3), postoperative drainage (ME-TLIF:82.1 ± 23.5 vs W-TLIF: 345.8 ± 65.2), initial postoperative back pain (ME-TLIF: VAS_3 days: 1.96 ± 0.60 VAS_7 days: 1.73 ± 0.53, W-TLIF: VAS_3 days: 2.48 ± 0.51 VAS_7 days: 1.87 ± 0.43), and hospitalization duration (ME-TLIF: 9.04 vs. W-TLIF: 11.29) were all significantly lower in the ME-TILF group (p < 0.05). However, there were no statistical differences between the two groups in VAS, ODI, and JOA at 1 month, 3 months, 6 months, and 1 year postoperatively (p > 0.05). The fusion rates of the two groups showed no notable difference (p > 0.05), while the X-ray exposure time in the ME-TLIF group was significantly longer than in the W-TLIF group (p < 0.05).

CONCLUSIONS

ME-TLIF surgery was an effective and satisfactory surgical technique to manage LDH. Although ME-TLIF increased the operation time and intraoperative fluoroscopic irradiation volume, it could effectively relieve low back pain from early postoperative onset and promote early postoperative recovery compared with W-TLIF.

Lumbar Interbody Fusion and Osteobiologics for Lumbar Fusion

Lumbar interbody fusion (LIF) is an excellent treatment option for a number of lumbar diseases. LIF can be performed through posterior, transforaminal, anterior, and lateral or oblique approaches. Each technique has its own pearls and pitfalls. Through LIF, segmental stabilization, neural decompression, and deformity correction can be achieved. Minimally invasive surgery has recently gained popularity and each LIF procedure can be performed using minimally invasive techniques to reduce surgery-related complications and improve early postoperative recovery. Despite advances in surgical technology, surgery-related complications after LIF, such as pseudoarthrosis, have not yet been overcome. Although autogenous iliac crest bone graft is the gold standard for spinal fusion, other bone substitutes are available to enhance fusion rate and reduce complications associated with bone harvest. This article reviews the surgical procedures and characteristics of each LIF and the osteobiologics utilized in LIF based on the available evidence.

Contralateral bridge fixation of freehand minimally invasive pedicle screws combined with unilateral MIS-TLIF vs. open TLIF in the treatment of multi-segmental lumbar degenerative diseases: A five years retrospective study and finite element analysis

Objective

To evaluate the efficacy, safety, feasibility and biomechanical stability of contralateral bridge fixation of freehand minimally invasive pedicle screws (Freehand MIPS) combined with unilateral minimally invasive surgery-transforaminal lumbar interbody fusion (MIS-TLIF) (smile-face surgery) and open TLIF for the treatment of multi-segmental lumbar degenerative diseases (LDDs).

Methods

From January 2013 to January 2016, clinical data of multi-segmental (2- or 3-level) LDDs receiving smile-face surgery or open TLIF were retrospectively collected and analyzed. The back and leg pain VAS and ODI were used to assess clinical outcomes preoperatively and postoperatively. The MacNab criteria were used to evaluate the satisfaction of patient. The disc height (DH), lumbar lordosis (LL) and segmental lordosis angle (SLA) were measured before and after surgery. We used patient's CT data to establish the finite element model of smile-face surgery and open TLIF, and analyze biomechanical stability of two methods.

Results

Smile-face surgery group showed shorter operation time, shorter incision, less blood loss, shorter hospital stay than open TLIF (P &lt; 0.05). The back VAS in smile-face surgery group was significantly lower than that in open TLIF immediately and 3 months after surgery, and no significant difference was observed 1 year, 2 years and 5 years after surgery. There was no significant difference in the leg pain VAS and ODI between both groups after surgery. No significant difference was observed between two groups in the DH, LL and SLA. At 5-year follow-up, grade I or II fusion was achieved in 99.00% (100/101) segments of smile-face surgery group and 97.67% (84/86) segments of open TLIF group according to Bridwell system. The complication rate of open TLIF was higher than that of smile-face surgery (24.32% vs. 0%, P &lt; 0.01). After verification, the established finite element model can accurately simulate the biological structure of lumbar spine and there was no significant difference in biomechanical stability between two methods.

Conclusions

Smile-face surgery has some advantages over open TLIF including smaller aggression, less blood loss, and lower cost, indicating that it is a good choice of treatment for multi-segmental LDDs. Both methods can achieve good biomechanical stability.

Postoperative Spinal Implant Infections (PSII)-A Systematic Review: What Do We Know So Far and What is Critical About It?

STUDY DESIGN

Systematic review.

OBJECTIVES

Postoperative spinal implant infections (PSII) are an increasing challenge in the daily clinical routine. This review summarizes existing knowledge in the field of PSII, including definitions, epidemiology, classifications, risk factors, pathogenesis, symptoms, diagnosis, and treatment.

METHODS

A systematic review was performed using a structured PubMed analysis, based on the PRISMA criteria. The search terminology was set as: "spinal implant associated infection OR spinal implant infection OR spinal instrumentation infection OR peri spinal implant infection." PubMed search was limited to the categories randomized controlled trials (RCT), clinical trials, meta-analysis and (systematic) reviews, whereas case reports were excluded. Studies from January 2000 to December 2020 were considered eligible. A total of 572 studies were identified, 82 references included for qualitative synthesis, and 19 for detailed sub analysis (12 meta-analysis, 7 prospective RCT).

RESULTS

Structural problems in the field of PSII were revealed, including (1) limited level of evidence in clinical studies (missing prospective RCT, metanalyzes), (2) small patient numbers, (3) missing standardized definitions, (4) heterogeneity in patient groups, and (5) redundancy in cited literature.

CONCLUSION

Evidence-based knowledge about spinal implant-associated infections is lacking. All involved medical fields should come together to define the term PSII and to combine their approaches toward research, training, and patient care.

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.

Minimally Invasive Transpedicular Screw Fixation: Review of 152 Cases in a Single Institution. Steep or Shallow Learning Curve?

BACKGROUND

 In this study, we analyze our institutional experience and personal impressions using minimally invasive spine surgery (MISS) to describe our learning curve and how experience influenced different parameters of the surgical procedure.

METHODS

 The study was conducted prospectively and included the first consecutive 152 patients treated with MISS techniques. Patient demographics, surgical data, length of hospital stay, and clinical outcome were reviewed. The cohort was divided into consecutive quarters. Comparison between the quarters and timeline analysis were made to assess the learning curve.

RESULTS

 Only percutaneous transpedicular screw fixation was performed in 65 cases, minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) in 70 cases, and vertebral body replacement in 4 cases. The average blood loss was 113.3, 115, 106.6, and 107.1 mL for each quarter. The average operative time was 155.0, 143.2, 134.5, and 133.8 minutes for the four quarters, whereas the average radiation exposure time was 105.4, 85.3, 46.2, and 45.2 seconds. Differences in the operative time and radiation exposure time between the first to third and the first to fourth quarters were statistically significant.

CONCLUSIONS

 Some advantages of MISS techniques could be observed with the very first cases and were not related significantly with the surgeon's experience with MISS. With the acquisition of more experience, some disadvantages of MISS techniques such as longer operative time and longer X-ray exposure can be substantially reduced. Surgical experience, familiarity of the team with the MISS instrumentation, and good patient selection are crucial for achieving all the benefits of MISS.

A pilot study of endoscope-assisted MITLIF with fluoroscopy-guided technique: intraoperative objective and subjective evaluation of disc space preparation

BACKGROUND

Adequate discectomy and endplate preparation are extremely crucial steps for spinal interbody fusion. Minimally invasive transforaminal lumbar interbody fusion MITLIF technique is safe and effective. However, concerns exist regarding sufficient disc space preparation from unilateral access. The purpose of this study, was to demonstrate our preliminary experience in objective and subjective evaluation of disc space preparation intraoperatively during endoscope-assisted MITLIF with fluoroscopy-guided, describing some of its possible advantages, and analyzing its safety and feasibility.

METHODS

From March 2018 to July 2019, three patients with degenerative spinal stenosis with radiculopathy and instability underwent endoscope-assisted MITLIF with fluoroscopy-guided. Patients' demographic data, clinical parameters, subsidence, and fusion were collected.

RESULTS

Patients were successfully treated by endoscope-assisted MITLIF with fluoroscopy-guided at single-level or two-level. Symptoms improved postoperatively in all patients, and no complications occurred during follow-up. No cage subsidence was observed. At 6-month postoperatively, there was bony fusion observed on computed tomography in two patients.

CONCLUSION

Endoscope-assisted MITLIF with fluoroscopy-guided is a safe and feasible technique to improve visualization during discectomy and endplate preparation objectively and subjectively, possibly increasing fusion rate and early time to fusion.

Single-level TLIF Versus LLIF at L4-5: A Comparison of Patient-reported Outcomes and Recovery Ratios

INTRODUCTION

Both transforaminal lumbar interbody fusion (TLIF) and lateral lumbar interbody fusion (LLIF) are suitable for achievement of lumbar arthrodesis. Comparative studies have observed complications and outcomes without stratification by lumbar level. This study aims to assess patient-reported outcome measures (PROMs) and recovery in TLIF and LLIF at L4-5.

METHODS

Patients undergoing primary, elective, single-level, TLIF or LLIF procedures at L4-5 were grouped. Demographics, perioperative characteristics, and postoperative complication rates were collected. PROMs included Patient-Reported Outcome Measurement Information System Physical Function, visual analog scale (VAS) back and leg, Oswestry Disability Index, and 12-Item Short-Form Physical Component Summary, and Mental Component Summary and were collected at preoperative, 6-week, 12-week, 6-month, 1-year, and 2-year time points. Delta values and recovery ratios (RRs) were calculated for all PROMs at all time points. Demographics, perioperative characteristics, and postoperative complications were compared using chi-squared and Student t-test for categorical and continuous variables, respectively. Differences in mean PROMs, delta values, and RR at each time point were evaluated using unpaired Student's t-test.

RESULTS

Three hundred sixty TLIF and 46 LLIF patients were included. Most (54.3%) were men, mean age 56.3 years, and mean body mass index 30.8 kg/m2. Body mass index and insurance significantly differed (P ≤ 0.045, all). TLIF showed significantly greater mean operative time, length of stay, and postoperative narcotic consumption (P < 0.033, all) and greater postoperative nausea/vomiting (P = 0.004). No preoperative PROMs significantly differed. TLIF cohort had significantly greater VAS back at 6 months and VAS leg at 12 weeks and 6 months (P < 0.034, all). No mean delta PROMs or RRs significantly differed.

DISCUSSION

LLIF demonstrated significantly reduced length of stay, postoperative narcotic consumption, and postoperative nausea/vomiting and significantly improved VAS back at 6 months and VAS leg at 12 weeks and 6 months versus TLIF. Although 2-year PROMs and RRs did not significantly differ, our findings may suggest improved midterm follow-up pain scores for LLIF patients.

Feasibility and Accuracy of Thoracolumbar Pedicle Screw Placement Using an Augmented Reality Head Mounted Device

Background: To investigate the accuracy of augmented reality (AR) navigation using the Magic Leap head mounted device (HMD), pedicle screws were minimally invasively placed in four spine phantoms. Methods: AR navigation provided by a combination of a conventional navigation system integrated with the Magic Leap head mounted device (AR-HMD) was used. Forty-eight screws were planned and inserted into Th11-L4 of the phantoms using the AR-HMD and navigated instruments. Postprocedural CT scans were used to grade the technical (deviation from the plan) and clinical (Gertzbein grade) accuracy of the screws. The time for each screw placement was recorded. Results: The mean deviation between navigation plan and screw position was 1.9 ± 0.7 mm (1.9 [0.3–4.1] mm) at the entry point and 1.4 ± 0.8 mm (1.2 [0.1–3.9] mm) at the screw tip. The angular deviation was 3.0 ± 1.4° (2.7 [0.4–6.2]°) and the mean time for screw placement was 130 ± 55 s (108 [58–437] s). The clinical accuracy was 94% according to the Gertzbein grading scale. Conclusion: The combination of an AR-HMD with a conventional navigation system for accurate minimally invasive screw placement is feasible and can exploit the benefits of AR in the perspective of the surgeon with the reliability of a conventional navigation system.

Long-term clinical outcome of minimally invasive versus open single-level transforaminal lumbar interbody fusion for degenerative lumbar diseases: a meta-analysis

BACKGROUND CONTEXT

Minimally invasive surgical transforaminal lumbar interbody fusion (MIS-TLIF) was developed in addition to open-TLIF to minimize iatrogenic soft-tissue damage. A potential disadvantage of MIS-TLIF is inadequate visualization, which may lead to incomplete neural decompression and a less robust arthrodesis. This may cause long-term problems and result in decreased patient satisfaction.

PURPOSE

To evaluate the long-term clinical outcome, measured by patient-reported outcomes (PROMs), of patients with degenerative lumbar diseases treated with single-level TLIF (open vs. minimally invasive) with a minimum follow-up of 2-years.

STUDY DESIGN

Meta-analysis.

METHODS

The systematic review was conducted according to the PRISMA guidelines. Relevant studies were identified from Pubmed, MEDLINE, EMBASE, Scopus, Web of Science, and CENTRAL from the date of inception to August 2019. The inclusion criteria were (1) longitudinal comparative studies of MIS-TLIF versus open-TLIF approach for degenerative spine disease (2) outcomes reported as PROMs, (3) minimum follow-up of 2-years.

RESULTS

Sixteen studies were included in the analysis. In total, 1,321 patients were included (660 MIS-TLIF& 661 open-TLIF). The following PROMS were analyzed: EQ-5D, SF, ODI, and VAS. Both techniques resulted in significant improvement in PROM, which remained significant at 2-years follow-up. However, no significant differences were found in all PROMs at 2-years follow-up. Both treatments resulted in a high rate of spinal fusion (80.5% vs. 91.1%; p=.29) and low rate of reoperation (3.0% vs. 2.4%; p=.50) or adjacent segment disease (12.6% vs. 12.40%; p=.50).

CONCLUSIONS

MIS-TLIF and open-TLIF have comparable long-term clinical outscomes. Both operations can significantly reduce pain and positively improve PROMs. No significant differences were found between both treatments in clinical outcomes at a follow-up of minimal 2-years. Therefore, MIS-TLIF seems to be an effective and safe alternative to traditional open-TLIF in the long-term.

Lumbar spine fusion outcomes using a cellular bone allograft with lineage-committed bone-forming cells in 96 patients

BACKGROUND

Instrumented posterior lumbar fusion (IPLF) with and without transforaminal interbody fusion (TLIF) is a common treatment for low back pain when conservative interventions have failed. Certain patient comorbidities and lifestyle risk factors, such as obesity and smoking, are known to negatively affect these procedures. An advanced cellular bone allograft (CBA) with viable osteogenic cells (V-CBA) has demonstrated high fusion rates, but the rates for patients with severe and/or multiple comorbidities remain understudied. The purpose of this study was to assess fusion outcomes in patients undergoing IPLF/TLIF using V-CBA with baseline comorbidities and lifestyle risk factors known to negatively affect bone fusion.

METHODS

This was a retrospective study of de-identified data from consecutive patients at an academic medical center who underwent IPLF procedures with or without TLIF, and with V-CBA. Baseline patient and procedure characteristics were assessed. Radiological outcomes included fusion rates per the Lenke scale. Patient-reported clinical outcomes were evaluated via the Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) for back and leg pain. Operating room (OR) times and intraoperative blood loss rates were also assessed.

RESULTS

Data from 96 patients were assessed with a total of 222 levels treated overall (mean: 2.3 levels) and a median follow-up time of 16 months (range: 6 to 45 months). Successful fusion (Lenke A or B) was reported for 88 of 96 patients (91.7%) overall, including in all IPLF-only patients. Of 22 patients with diabetes in the IPLF+TLIF group, fusion was reported in 20 patients (90.9%). In IPLF+TLIF patients currently using tobacco (n = 19), fusion was reported in 16 patients (84.3%), while in those with a history of tobacco use (n = 53), fusion was observed in 48 patients (90.6%). Successful fusion was reported in all 6 patients overall with previous pseudarthrosis at the same level. Mean postoperative ODI and VAS scores were significantly reduced versus preoperative ratings.

CONCLUSION

The results of this study suggest that V-CBA consistently yields successful fusion and significant decreases in patient-reported ODI and VAS, despite patient comorbidities and lifestyle risk factors that are known to negatively affect such bony healing.

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.

Resident Involvement in Posterior Lumbar Interbody Fusion is Associated With Increased Readmissions and Operative Time, But No Increased Short-term Risks

STUDY DESIGN

A retrospective cohort study.

OBJECTIVE

The aim was to compare rates of adverse events and additional posterior lumbar interbody fusion (PLIF) cases assisted by residents versus cases performed solely by an orthopedic attending.

SUMMARY OF BACKGROUND DATA

PLIF is a widely accepted surgical technique for the management of a variety of spinal conditions requiring spinal stabilization and fusion. However, no published studies have assessed the effects of resident involvement on intraoperative and postoperative outcomes in PLIF.

METHODS

This retrospective study utilized the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) registry from 2007 to 2012 to identify patients who underwent PLIF procedures. A propensity score matching model was utilized to reduce patient cohort variances. The perioperative data and outcomes in the matched population were analyzed using paired t test and the McNemar test in order to assess, based on resident presence, the rates of postoperative adverse events, readmission, reoperation within 30 days, and operative time.

RESULTS

In total, 1633 patients undergoing PLIF were included in the study, with 24.62% involving resident participation. The propensity score matching algorithm yielded 396 well-matched resident and nonresident pairs. Patients undergoing PLIF involving a resident were associated with a higher rate of readmission (1.77% vs. 0.00%; P=0.008), and longer operative time (245.7 vs. 197.7 min; P<0.001). However, these procedures were not associated with any significant difference in minor or severe adverse events.

CONCLUSIONS

Resident involvement in PLIF was associated with an increased rate of readmissions, and operative time; however, was not associated with an increase in minor or severe adverse events. Further investigation is needed to characterize the role of resident involvement based on level of training experience, as well as methods to improve the learning curve to independence while reducing postoperative hospital length of stay.

LEVEL OF EVIDENCE

Level III-retrospective comparative study.

Accuracy and technical limits of percutaneous pedicle screw placement in the thoracolumbar spine

PURPOSE

The two-dimensional fluoroscopic method of percutaneous pedicle screw instrumentation has been clinically described as reliable method in the caudal thoracic and lumbosacral spine. Its accuracy has not been clearly reported in the cranial thoracic spine. The aim of this in vitro study was to investigate percutaneous pedicle screw placement accuracy according to pedicle dimensions and vertebral levels.

METHODS

Six fresh-frozen human specimens were instrumented with 216 screws from T1 to S1. Pedicle isthmus widths, heights, transversal pedicles and screws were measured on computed tomography. Pedicle cortex violation ≥ 2 mm was defined as screw malposition.

RESULTS

The narrowest pedicles were at T3-T5. A large variability between transversal pedicle axes and percutaneous pedicle screw was present, depending on the spinal level. Screw malposition rates were 36.1% in the cranial thoracic spine (T1-T6), 16.7% in the caudal thoracic spine (T7-T12), and 6.9% in the lumbosacral spine (L1-S1). The risk for screw malposition was significantly higher at cranial thoracic levels compared to caudal thoracic (p = 0.006) and lumbosacral (p < 0.0001) levels. Cortex violation ≥ 2 mm was constantly present if the pedicle width was < 4.8 mm.

CONCLUSION

Percutaneous pedicle screw placement appears safe in the caudal thoracic and lumbosacral spine. The two-dimensional fluoroscopic method has a limited reliability above T7 because of smaller pedicle dimensions, difficulties in visualizing radiographic pedicle landmarks and kyphosis.

Radiation Exposure in Minimally Invasive Lumbar Fusion Surgery: A Randomized Controlled Trial Comparing Conventional Fluoroscopy and 3D Fluoroscopy-based Navigation

STUDY DESIGN

Randomized controlled trial.

OBJECTIVE

The aim of this study was to compare the dosemetrically determined radiation exposure of surgeon and patient during minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) using conventional 2D fluoroscopy (FLUORO) or 3D fluoroscopy-based navigation (NAV).

SUMMARY OF BACKGROUND DATA

MIS TLIF was shown to exhibit higher radiation exposures compared to open techniques. In particular, the routinely exposed surgeon encounters the risks of increased radiation doses. With the additional use of intraoperative 3D navigation, major steps of the operation can be performed without exposing the operating room staff to ionizing radiation.

METHODS

Forty-four patients undergoing monosegmental MIS TLIF were randomized into the two intraoperative imaging technique groups (FLUORO or NAV). The primary endpoint was the radiation exposure of the surgeon; the secondary endpoints were the radiation exposure of the patient and C-arm readings.

RESULTS

After exclusion of three patients, 41 patients were analyzed. In general, the average radiation exposure of the surgeon was lower in the NAV group without being statistically significant. The radiation exposure of the patient was significantly higher in the NAV group at all dosemeter sites. The average fluoroscopy time was 63 ± 36 versus 109 ± 31 sec (FLUORO versus NAV group, P < 0.001).

CONCLUSION

The additional use of intraoperative 3D fluoroscopy-based navigation compared to conventional 2D fluoroscopy alone showed a nonsignificant reduction of the radiation exposure of the surgeon in monosegmental MIS TLIF, while increasing the radiation exposure of the patient.

LEVEL OF EVIDENCE

1.

Surgical revision strategies for postoperative spinal implant infections (PSII)

Over the last years the number of spine surgeries with instrumentation has grown to an indispensable column in the treatment for different pathologies of the spine. A further increase in the incidence of instrumented spinal surgery is expected throughout the next years. Although the implementation and development of new techniques offer faster and more minimal invasive procedures, shortening surgery time, reducing soft tissue injury and revision due to hardware misplacement, the incidence of postoperative spinal implant infections (PSII) remains high. PSII related complications and revision procedures pose an enormous socioeconomic burden. Therefore, standardized strategies and protocols for treatment of PSII are urgently needed. While in former times hardware exchange or hardware removal was common practise in the field of spine surgery this approach has changed over the last years. Although the evidence from clinical studies in the field of PSII is of limited evidence, critical variables for revision strategies of PSII have been identified. Further, to quickly advance in the field of PSII it is certainly important to extrapolate and learn using data regarding the management from other fields of prosthetic joint infections. This should include clinical as well as experimental work in particular in the context of the biofilm, sonication as well as microbiological concepts. Over the last years, at our institution standardized procedures for diagnostic, surgical as well as antimicrobial treatment have been developed, based on the latest recommendations in peer-reviewed literature and our own data. Here we give an overview about surgical revision strategies for PSII and discuss the key points of our standardized protocol.

Direct Pars Defect Tubular Decompression and TLIF for the Treatment of Low-Grade Adult Isthmic Spondylolisthesis: Surgical Challenges and Nuances of a Muscle-Sparing Minimally Invasive Approach

We present an illustrative report on the use of a minimally invasive, muscle-sparing, direct pars defect decompression with transforaminal lumbar interbody fusion (TLIF) and instrumentation for the treatment of low-grade adult isthmic spondylolysis with spondylolisthesis and discuss the surgical challenges and nuances associated with the technique.

Minimally Invasive Transforaminal Lumbar Interbody Fusion With Intraoperative Fluoroscopy for Disc Space Preparation: Analysis of Fusion Rate and Clinical Results

BACKGROUND

Meticulous disc space preparation is an important step toward ensuring arthrodesis in the interbody fusion procedure. Although minimally invasive techniques are becoming increasingly advanced in lumbar interbody fusion, concerns exist regarding adequate discectomy and sufficient endplate preparation from a transforaminal lumbar approach.

OBJECTIVE

To describe the radiographic and clinical outcomes of single-level minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) using the intraoperative fluoroscopy-guided method for disc space preparation.

METHODS

This is a retrospective study of 25 patients operated between June 2016 and Dec 2017. The radiographic outcomes included the intraoperative percentage of disc space preparation, fusion, and subsidence. Percentage of disc space preparation was calculated through intraoperative fluoroscopic imaging. Clinical outcomes included visual analog scale (VAS), Oswestry Disability Index (ODI), and satisfaction rate.

RESULTS

Mean age of patients was 62.9 yr. The mean follow-up period was 22 mo. Mean extents of disc space preparation were 61.5% in the anteroposterior view and 80.3% in the lateral view. Fusion rates were 86% and 92% at 6 and 12-mo postoperatively, respectively. All patients showed clinical improvement according to VAS and ODI.

CONCLUSION

MI-TLIF with intraoperative fluoroscopy-guided disc space preparation is shown to lead to potentially improved fusion rate. It is a safe and effective surgical method for degenerative lumbar disease. Additionally, in cases of cage subsidence caused by the endplate violation during disc space preparation, thorough sufficient bone grafting of the defect region avoids pseudoarthrosis.

Lumbar Interbody Fusion: Techniques, Pearls and Pitfalls

Lumbar interbody fusion (LIF) is an effective and popular surgical procedure for the management of various spinal pathologies, especially degenerative diseases. Currently, LIF can be performed with posterior, transforaminal, anterior, and lateral approaches by open surgery or minimally invasive surgery (MIS). Each technique has its own advantages and disadvantages. In general, posterior LIF is a well-established procedure with good fusion rates and low complication rates but is limited by the possibility of iatrogenic injury to the neural structures and paraspinal muscles. Transforaminal LIF is frequently performed using an MIS technique and has an advantage of reducing these iatrogenic injuries. Anterior LIF (ALIF) can restore the disk height and sagittal alignment but has inherent approach-related challenges such as visceral and vascular complications. Lateral LIF and oblique LIF are performed using an MIS technique and have shown postoperative outcomes similar to ALIF; however, these approaches carry a risk of injury to psoas, lumbar plexus, and vascular structures. Herein, we provide a detailed description of the surgical procedures of each LIF technique. We shall then consider the pearls and pitfalls, as well as propose surgical indications and contraindications based on the available evidence in the literatures.

Hidden blood loss and its possible risk factors in minimally invasive transforaminal lumbar interbody fusion

Background

With respect to spinal surgeries, elucidating absolute and relative amount of hidden blood loss (HBL) is of great importance in order to avoid aforementioned potential complications. To evaluate HBL and its possible risk factors among patients undergoing minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) for lumbar degenerative diseases.

Methods

Between June 2018 and March 2019, 137 consecutive patients with lumbar degenerative disease, who underwent operation with MIS-TLIF technique, were enrolled in this study. The patient’s demographic characteristics and blood loss-related parameters were collected, respectively. The Pearson or Spearman correlation analysis was used to investigate an association between patient’s characteristics and HBL. Multivariate linear regression analysis was used to confirm independent risk factors of HBL.

Results

A total of 137 patients (86 males and 51 females, age range 19–78 years) were reviewed in our hospital. A substantial amount of HBL (488.4 ± 294.0 ml, 52.5% of TBL) occurred after MIS-TLIF. Multivariate linear regression showed that the age, muscle thickness, the Patients’ Society of Anesthesiologists (ASA) classification, patient’s blood volume (PBV), total blood loss (TBL), postoperative (i.e., day 2 or 3) hematocrit (Hct), Hct loss, and fibrinogen level were independent risk factors for HBL (P1 = 0.000, P2 = 0.002, P3 = 0.006, P4 = 0.002, P5 = 0.003, P6 = 0.048, P7 = 0.004, P8 = 0.000).

Conclusion

A large amount of HBL was incurred in patients undergoing MIS-TLIF. More importantly, the age, muscle thickness, ASA classification, PBV, TBL, postoperative Hct, Hct loss, and fibrinogen level were independent risk factors for HBL in MIS-TLIF. HBL and its risk factors should be paid more attention to during the perioperative period.

Two-year results of a double-blind multicenter randomized controlled non-inferiority trial of polyetheretherketone (PEEK) versus silicon nitride spinal fusion cages in patients with symptomatic degenerative lumbar disc disorders

Background

During lumbar spinal fusion, spacer cages are implanted to provide vertebral stability, restore sagittal alignment, and maintain disc and foraminal height. Polyetheretherketone (PEEK) is commonly used by most spine surgeons. Silicon nitride (Si₃N₄) is a less well-known alternative although it was first used as a spacer in lumbar fusion over 30 years ago. The present study was designed to see if Si₃N₄ cages would perform similarly to PEEK in a randomized controlled trial.

Methods

A non-inferiority multicenter 100-patient study was designed where both the observer and patient were blinded. Single- or double-level transforaminal lumbar interbody fusion with pedicle screw fixation using an oblique PEEK or Si₃N₄ cage was performed. The primary non-inferiority outcome was the Roland-Morris Disability Questionnaire (RMDQ). Secondary measures included the Oswestry Disability Questionnaire, Visual Analogue Scales (VAS) for back and leg pain, SF-36 Physical and Mental Function indices, patient and surgeon Likert scores on perceived recovery, and X-ray and CT radiological evaluations for subsidence, segmental motion, and fusion. Follow-up evaluations occurred at 3, 6, 12, and 24 months.

Results

After exclusions for protocol violations and canceled surgeries, 92 patients were randomized (i.e., 48 for PEEK and 44 for Si₃N₄). There were no differences in baseline demographics, pre-operative disabilities, or pain scores between the groups. Both treatment arms showed significant improvements in disability, pain, and recovery scores. No significant differences were observed for subsidence, segmental motion, or fusion. For the primary outcome (i.e., RMDQ scores), the non-inferiority of Si₃N₄ compared to PEEK could not be established using the original protocol criteria. However, the comparison was undermined by larger than anticipated patient fallout coupled with higher than expected RMDQ score standard deviations. A post hoc analysis coupled with a more extensive review of the literature was conducted which resulted in the selection of a revised clinically justified non-inferiority margin; and using this method, the non-inferiority of Si₃N₄ was affirmed.

Conclusions

This study demonstrated that the use of either PEEK or Si₃N₄ cages is safe and effective for patients undergoing lumbar spine fusion for chronic degenerative disc disease.

Clinical Application of CT Navigation in treatment of Lumbar Spondylolisthesis with Minimally Invasive Surgery - Transforaminal Lumbar Interbody Fusion

Objective:

To explore the clinical effect of the application of CT navigation in the treatment of lumbar spondylolisthesis with minimally invasive surgery - transforaminal lumbar interbody fusion (MIS-TLIF).

Methods:

A retrospective study was conducted on 30 patients with lumbar spondylolisthesis who were continuously treated in linyi central hospital from May 2018 to March 2019.The patients were divided into two groups,15 patients treated with MIS-TLIF with the aid of CT navigation during the operation were included into an observation group. Another 15 patients were treated with open transforaminal lumbar interbody fusion as the control group. The baseline information, including gender, age and course of disease, perioperative period and imaging conditions, and VAS and ODI scores of patients in the two groups were collected and analyzed.

Results:

Fifteen patients were included into the observation group, including 9 male and 6 female patients with an average age of 52.60 ± 6.31 and a course of disease of 16.33 ± 6.00 months. The other 15 patients were included into the observation group, including seven male and eight female patients with an average age of 52.87 ± 7.38 and a course of disease of 19.13 ± 9.89 months. The difference in the gender, age and course of disease between the two groups had no statistical significance (P > 0.05). However, the difference in the duration of operation and intraoperative blood loss between the two groups had statistical significance (P< 0.05). There were no statistically significant differences in wound complications, neurological complications, preoperative slippage rate, postoperative slippage rate, slippage reduction rate and screw placement accuracy (P > 0.05). VAS scores of the two groups were statistically significant from six months after surgery (P < 0.01). There was no significant difference in ODI between the two groups at any time point (P >, 0.05). VAS and ODI scores were improved at each time point compared with those before surgery.

Conclusion:

The minimally invasive transforaminal lumbar fusion performed with the aid of CT navigation during the operation shortens the duration of operation and the amount of bleeding, reduces the back pain, is beneficial to the early postoperative functional exercise, and speeds up the postoperative recovery.

Percutaneous Endoscopic Transforaminal Discectomy versus Conventional Open Lumbar Discectomy for Upper Lumbar Disc Herniation: A Comparative Cohort Study

Background

Percutaneous endoscopic transforaminal discectomy (PETD) is regarded as a viable alternative option for upper lumbar disc herniation (LDH). However, few studies have evaluated PETD for upper LDH, and no study has compared the advantages of endoscopic procedures versus conventional surgery. The present study was aimed at comparing the surgical outcome and safety of PETD versus conventional open lumbar discectomy in the treatment of upper LDH.

Methods

Data from 42 patients treated for upper LDH from July 2015 to July 2018 were retrospectively analyzed, including 21 patients treated with PETD (PETD group) and 21 patients treated with conventional posterior lumbar discectomy (open group). The two groups were compared regarding demographic information, physical examination, radiological evaluations, and perioperative indicators. The clinical outcomes were assessed in accordance with the Oswestry Disability Index (ODI), visual analog scale (VAS), and modified MacNab criteria.

Results

The postoperative ODI and VAS scores were significantly improved in both groups compared with the preoperative baseline values (P < 0.001), and the satisfactory rate was 90.5% in both groups in accordance with the modified MacNab criteria. There were no significant differences between the two groups in the clinical outcomes and complication rate (P < 0.001), and the satisfactory rate was 90.5% in both groups in accordance with the modified MacNab criteria. There were no significant differences between the two groups in the clinical outcomes and complication rate (P < 0.001), and the satisfactory rate was 90.5% in both groups in accordance with the modified MacNab criteria. There were no significant differences between the two groups in the clinical outcomes and complication rate (

Conclusions

PETD has a similar outcome to the conventional surgical method for the treatment of upper LDH but provides the typical advantages of minimally invasive procedures such as reduced iatrogenic injury, minimal activity restrictions, and accelerated ambulation recovery postoperatively.

Randomized Controlled Trial of Posterior Lumbar Interbody Fusion With Ti- and CaP-Nanocoated Polyetheretherketone Cages: Comparative Study of the 1-Year Radiological and Clinical Outcome

Background

Polyetheretherketone (PEEK) is a popular material for posterior lumbar interbody fusion (PLIF) cages, although osseointegration remains limited. To optimize PEEK cage characteristics, titanium (Ti) and calcium phosphate (CaP) nanocoatings have been developed with proven mechanical safety. This multicenter randomized controlled trial compared the clinical and radiological outcome parameters of nanocoated and uncoated PEEK cages, up to 1 year after surgery.

Methods

Standard open PLIF surgery was performed on 127 patients, randomized in 3 groups: Ti-nanocoated (n = 44), CaP-nanocoated (n = 46), and uncoated PEEK cages (n = 37). Clinical assessments up to 1 year after surgery included visual analogue scales (VASs), Oswestry Disability Index (ODI), and 36-Item Short Form Survey (SF-36). Primary radiological outcome parameters were implant stability and fusion status, assessed by x-ray and computed tomography (CT) scans. Patients, surgeons, and postsurgery analysts were blinded.

Results

PLIF surgery with all cage types resulted in significant improvements of clinical outcome parameters, exceeding the minimum clinically important differences. No significant differences in VAS, ODI, or SF-36 scores were found among the 3 groups. One year after the surgery, 65.6% of patients with uncoated PEEK cages achieved definite fusion. Significantly more patients with nanocoated PEEK cages achieved definite fusion: 93.9% for Ti nanocoating (P = .0034) and 88.0% for CaP nanocoating (P = .032). No significant differences in fusion were found between the nanocoated cage types (P = .4318).

Conclusions

The similar clinical outcome improvements after 1 year suggest that nanocoated PEEK cages have the same safety and efficacy as the clinically accepted uncoated PEEK cages. Furthermore, nanocoated PEEK cages achieved a better fusion rate than uncoated PEEK cages at the 1-year follow-up. A 5-year follow-up study is warranted to revisit the findings.

Clinical Relevance

The safety, efficacy, and enhanced osseointegration of nanocoated PEEK cages were demonstrated. Osseointegration is a significant predictor of positive long-term clinical outcomes and improved implant longevity, implying a clinical added value of nanocoatings. Enhanced osseointegration becomes even more important in minimally invasive spine surgery and in patients at risk for incomplete fusion.

Augmented and Virtual Reality Instrument Tracking for Minimally Invasive Spine Surgery: A Feasibility and Accuracy Study

STUDY DESIGN

Cadaveric animal laboratory study.

OBJECTIVE

To evaluate the feasibility and accuracy of pedicle cannulation using an augmented reality surgical navigation (ARSN) system with automatic instrument tracking, yielding feedback of instrument position in relation to deep anatomy.

SUMMARY OF BACKGROUND DATA

Minimally invasive spine surgery (MISS) has the possibility of reducing surgical exposure resulting in shorter hospital stays, lower blood loss and infection rates compared with open surgery but the drawback of limiting visual feedback to the surgeon regarding deep anatomy. MISS is mainly performed using image-guided 2D fluoroscopy, thus exposing the staff to ionizing radiation.

METHODS

A hybrid operating room (OR) equipped with a robotic C-arm with integrated optical cameras for augmented reality instrument navigation was used. In two pig cadavers, cone beam computed tomography (CBCT) scans were performed, a 3D model generated, and pedicle screw insertions were planned. Seventy-eight insertions were performed. Technical accuracy was assessed on post-insertion CBCTs by measuring the distance between the navigated device and the corresponding pre-planned path as well as the angular deviations. Drilling and hammering into the pedicle were also compared. Navigation time was measured. An independent reviewer assessed a simulated clinical accuracy according to Gertzbein.

RESULTS

The technical accuracy was 1.7 ± 1.0 mm at the bone entry point and 2.0 ± 1.3 mm at the device tip. The angular deviation was 1.7 ± 1.7° in the axial and 1.6 ± 1.2° in the sagittal plane. Navigation time per insertion was 195 ± 93 seconds. There was no difference in accuracy between hammering and drilling into the pedicle. The clinical accuracy was 97.4% to 100% depending on the screw size considered for placement. No ionizing radiation was used during navigation.

CONCLUSION

ARSN with instrument tracking for MISS is feasible, accurate, and radiation-free during navigation.

LEVEL OF EVIDENCE

3.

Validation of diffuse reflectance spectroscopy with magnetic resonance imaging for accurate vertebral bone fat fraction quantification

Safe and accurate placement of pedicle screws remains a critical step in open and minimally invasive spine surgery. The diffuse reflectance spectroscopy (DRS) technique may offer the possibility of intra-operative guidance for pedicle screw placement. Currently, Magnetic Resonance Imaging (MRI) is one of the most accurate techniques used to measure fat concentration in tissues. Therefore, the purpose of this study is to compare the accuracy of fat content measured invasively in vertebrae using DRS and validate it against the Proton density fat fraction (PDFF) derived via MRI. Chemical shift-encoding-based water-fat imaging of the spine was first performed on six cadavers. PDFF images were computed and manually segmented. 23 insertions using a custom-made screw probe with integrated optical fibers were then performed under cone beam computer tomography (CBCT). DR spectra were recorded at several positions along the trajectory as the optical screw probe was inserted turn by turn into the vertebral body. Fat fractions determined via DRS and MRI techniques were compared by spatially correlating the optical screw probe position within the vertebrae on CBCT images with respect to the PDFF images. The fat fraction determined by DRS was found to have a high correlation with those determined by MRI, with a Pearson coefficient of 0.950 (P< 0.001) as compared with PDFF measurements calculated from the MRI technique. Additionally, the two techniques were found to be comparable for fat fraction quantification within vertebral bodies (R² = 0.905).

Time Course Observation of Outcomes between Minimally Invasive Transforaminal Lumbar Interbody Fusion and Posterior Lumbar Interbody Fusion

The purpose of this study is to compare the long-term patient-outcomes, spinal fusion, and incidence of adjacent segment degeneration (ASD) between minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) and open posterior lumbar interbody fusion (O-PLIF). We retrospectively reviewed 70 consecutive cases who underwent single-level MIS-TLIF or O-PLIF from March 2010 to July 2013. All the patients achieved a minimum of 5-year follow-up. Data collected for each patient included demographic data, perioperative data, and complications. Clinical outcomes were evaluated with Oswestry disability index and visual analogue scale (VAS). Radiological outcomes included fusion rate and ASD. About 34 patients of MIS-TLIF and 36 patients of O-PLIF were enrolled. Higher Charlson comorbidity index scores were noted in MIS-TLIF than in O-PLIF. Blood loss was significantly lower in MIS-TLIF than O-PLIF. There were significant improvements in clinical and radiological outcomes in both groups. At 6 months, in MIS-TLIF group had significantly lower VAS for back pain and disc height compared with in O-PLIF group. The fusion rate was similar between the two groups at 5-year follow-up. Although the total complication rates were similar between the two groups, both the incidence of ASD was significantly higher in O-PLIF group than MIS-TLIF group (P = 0.032). In conclusion, this study indicates that MIS-TLIF is comparable to O-PLIF in terms of fusion rates and clinical outcomes in single-segment degenerative lumbar diseases. In addition, compared with O-PLIF, MIS-TLIF has the advantages of lesser blood loss, faster recovery, and lower incidence of ASD.

Device solutions for a challenging spine surgery: minimally invasive transforaminal lumbar interbody fusion (MIS TLIF)

INTRODUCTION

Lumbar interbody fusion remains a mainstay in the treatment of degenerative spinal pathology. Interbody devices are often used in an attempt to improve fusion rates and outcomes. Minimally invasive techniques lend unique advantages, but are challenging and often plagued with complications. Specifically, minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) has a steep learning curve and there is a lack of concise information on solutions to optimize outcomes.

AREAS COVERED

This review details an appropriate surgical technique of MIS TLIF and includes an overview of the components that go into a successful procedure. A thorough literature search of the PubMed database was completed to provide a comprehensive analysis of the interbody devices, posterolateral fixation, and osteobiologics.

EXPERT OPINION

MIS TLIFs have demonstrated successful clinical and radiographic outcomes and have become a mainstay for treating various degenerative lumbar pathologies. As minimally invasive techniques continue to evolve, devices and biologics will continue to expand the indications for MIS TLIFs and will optimize long-term outcomes.

A comparison of narcotic usage and length of post-operative hospital stay in open versus minimally invasive lumbar interbody fusion with percutaneous pedicle screws

Background

Instrumented lumbar fusion can be accomplished through open or minimally invasive techniques. The focus of this study was to compare perioperative narcotic usage and length of hospital stay between patients undergoing open versus minimally invasive spinal surgery (MISS).

Methods

A retrospective chart review was performed on 110 patients who underwent instrumented lumbar fusion over 2 years at our institution. These patients were divided into two groups: those that received open transforaminal interbody fusion (n=69), and those whose surgeries were performed minimally invasively with lateral lumbar transpsoas interbody fusion (LLIF) and percutaneous pedicle screws (n=41). Narcotic usage was recorded for both groups intra-operatively and post-operatively throughout their hospital stay. These values were standardized using an equianalgesia chart.

Results

Average narcotic usage post-operatively was significantly lower for the LLIF group relative to those who underwent open lumbar fusion (278.48 vs. 442.06 mg, P=0.03). The average length of post-operative hospital stay was significantly shorter for patients who underwent LLIF compared to those who had an open procedure (4.10 vs. 6.19 days, P=0.02).

Conclusions

Patients who underwent minimally invasive surgery (MIS) LLIF had decreased overall use of opioids in the perioperative period and shorter hospital stays when compared to patients who underwent the open transforaminal interbody fusion approach. These findings support pre-existing literature in favor of LLIF MISS with regards to the above stated outcome measures. The long-term benefits of MISS with regards to narcotic usage in spine patients are not yet known.

Feasibility and Accuracy of Thoracolumbar Minimally Invasive Pedicle Screw Placement With Augmented Reality Navigation Technology

STUDY DESIGN

Cadaveric laboratory study.

OBJECTIVE

To assess the feasibility and accuracy of minimally invasive thoracolumbar pedicle screw placement using augmented reality (AR) surgical navigation.

SUMMARY OF BACKGROUND DATA

Minimally invasive spine (MIS) surgery has increasingly become the method of choice for a wide variety of spine pathologies. Navigation technology based on AR has been shown to be feasible, accurate, and safe in open procedures. AR technology may also be used for MIS surgery.

METHODS

The AR surgical navigation was installed in a hybrid operating room (OR). The hybrid OR includes a surgical table, a motorized flat detector C-arm with intraoperative 2D/3D imaging capabilities, integrated optical cameras for AR navigation, and patient motion tracking using optical markers on the skin. Navigation and screw placement was without any x-ray guidance. Two neurosurgeons placed 66 Jamshidi needles (two cadavers) and 18 cannulated pedicle screws (one cadaver) in the thoracolumbar spine. Technical accuracy was evaluated by measuring the distance between the tip of the actual needle position and the corresponding planned path as well as the angles between the needle and the desired path. Time needed for navigation along the virtual planned path was measured. An independent reviewer assessed the postoperative scans for the pedicle screws' clinical accuracy.

RESULTS

Navigation time per insertion was 90 ± 53 seconds with an accuracy of 2.2 ± 1.3 mm. Accuracy was not dependent on operator. There was no correlation between navigation time and accuracy. The mean error angle between the Jamshidi needles and planned paths was 0.9° ± 0.8°. No screw was misplaced outside the pedicle. Two screws breached 2 to 4 mm yielding an overall accuracy of 89% (16/18).

CONCLUSION

MIS screw placement directed by AR with intraoperative 3D imaging in a hybrid OR is accurate and efficient, without any fluoroscopy or x-ray imaging during the procedure.

LEVEL OF EVIDENCE

N/A.

MINIMALLY INVASIVE CIRCUMFERENTIAL ARTHRODESIS OF THE FOURTH LUMBAR LEVEL FOR SPONDYLOLISTHESIS TREATMENT

ABSTRACT Objective: To know the clinical and radiographic results of patients with L4-L5 degenerative spondylolisthesis grade I, II, and III surgically treated with minimally invasive 360-degree arthrodesis. To determine the clinical and radiographic results according to the Oswestry Index 6 months after surgery and the percentage of postsurgical reduction in these patients. Methods: The present study was developed in the Department of Spinal Surgery of the Unidad Médica de Alta Especialidad Lomas Verdes, from October 2016 to August 2017. It is a prospective, cross-sectional, comparative observational study. We evaluated the reduction of the listhesis using pre and post-operative radiographs, as well as the Oswestry Disability Index. Results: The sample was composed of 12 patients, eight females and four males, showing a statistical significance in the Student’s t test, with p=0.05 for both variables. Conclusions: Degenerative spondylolisthesis of the 4th lumbar level is a very frequent pathology that affects groups of productive age and represents a burden not only for the patient, but also for the community. This surgical technique showed a high level of security and confidence for its resolution, showing results comparable to the literature. However, it requires certain technical resources and training to be performed. Evidence Level II; Prospective comparative study.

TLIF-MIS VS TLIF-OPEN: COST EVALUATION

ABSTRACT Objective: To evaluate the direct costs of transforaminal lumbar interbody fusion (TLIF) and minimally invasive surgery (MIS) or open technique (OPEN). Methods: The present study is descriptive and retrospective. Sixteen patients with degenerative spinal pathology operated on with the TLIF MIS technique and TLIF OPEN were included over a 13-month period. Days of hospital stay, blood loss, surgical time, medical care and costs were compared. Results: The mean number of days of hospital stay was 6.7 ± 4.3 days with TLIF MIS and 11.1 ± 6.5 days with TLIF OPEN. The blood loss was 307 ± 81.6 ml (range 200400 ml) with TLIF MIS and 803 ± 701.3 ml (range 200-1800 ml) with TLIF OPEN. The surgical time was 320 ± 92.6 minutes (range 210-500 minutes) in TLIF MIS and 372 ± 95.2 minutes (280-540 minutes) in TLIF OPEN. Conclusions: The difference in surgical costs and time between the two procedures was not statistically significant. There was less bleeding during the TLIF-MIS surgery, as well as a correlation between shorter days of hospital stay proportional to bleeding and surgical time, which translates into a reduction in the cost of these items. Level of Evidence III; Analysis based on alternatives and limited costs.

Fully endoscopic lumbar interbody fusion using a percutaneous unilateral biportal endoscopic technique: technical note and preliminary clinical results

OBJECTIVE Minimally invasive spine surgery can minimize damage to normal anatomical structures. Recently, fully endoscopic spine surgeries have been attempted for lumbar fusion surgery. In this study, the authors performed a percutaneous unilateral biportal endoscopic (UBE) technique as a minimally invasive surgery for lumbar fusion. The purpose of this study is to present the UBE technique of fully endoscopic lumbar interbody fusion (LIF) and to analyze the clinical results. METHODS Patients who were to undergo single-level fusion surgery from L3-4 to L5-S1 were enrolled. Two channels (endoscopic portal and working portal) were used for endoscopic lumbar fusion surgery. All patients underwent follow-up for more than 12 months. Demographic characteristics, diagnosis, operative time, and estimated blood loss were evaluated. MRI was performed on postoperative Day 2. Clinical evaluations (visual analog scale [VAS] for the leg and Oswestry Disability Index [ODI] scores) were performed preoperatively and during the follow-up period. RESULTS A total of 69 patients (24 men and 45 women) were enrolled in this study. The mean follow-up period was 13.5 months. Postoperative MRI revealed optimal direct neural decompression after fully endoscopic fusion surgery. VAS and ODI scores significantly improved after the surgery. There was no postoperative neurological deterioration. CONCLUSIONS Fully endoscopic LIF using the UBE technique may represent an alternative minimally invasive LIF surgery for the treatment of degenerative lumbar disease. Long-term follow-up and larger clinical studies are needed to validate the clinical and radiological results of this surgery.

Transforaminal Lumbar Interbody Fusion With Viable Allograft: 75 Consecutive Cases at 12-Month Follow-up

Background

When conservative treatments fail to alleviate the discomfort of abnormal motion, spinal fusion has been shown to provide symptomatic treatment for spinal instability, stenosis, spondylolisthesis, and symptomatic degenerative disc disease. The trend and rates of fusion over the past few years have been dramatic in the United States. Accompanying that higher incidence has been the shifting from traditional open surgery to minimally invasive techniques to reduce scar tissue formation, extent of muscle stripping, and muscle retraction which all have been shown to adversely affect outcomes. Other reasons supporting the widespread transition to minimally invasive surgical (MIS) techniques include decreased postoperative pain, decreased intraoperative blood loss, shorter postoperative hospital stay, faster return to normal activity, and reduced reoperation rates. Spinal fusion procedures rely on a bony fusion substrate in addition to fixation hardware. While available grafting options include autogenous, allogeneic, and synthetic materials, recent interest in viable allograft material with living cells has drawn attention and attraction for incorporating a biologic basis for regenerative consideration. A recent viable allograft, complete with cellular and designated bone carrier (VIA Graft, Vivex Biomedical, Marietta, Georgia) has been developed. This study represents a retrospective review of a single-practice, single-surgeon evaluation of the product in 75 consecutive patients for fusion by computed tomography (CT) and radiographic evaluation at 12 months in conjunction with a MIS approach. Viable allograft was used to fill the peri-implant space, and central implant lumen was filled with a cancellous bone sponge soaked in perivertebral bone marrow. Posterolateral supplementation was attained with beta-tricalcium phosphate as a bulking agent.

Methods

A retrospective review identified patients treated for both primary and revision surgery who received VIA Graft cellular bone matrix material in minimally invasive interbody fusion (MIS-TLIF) with a minimum of 12-month follow up. The patient diagnoses included radiculopathy in all instances and varied collateral indications such as foraminal collapse, recurrent disc herniation, and spondylolisthesis to which pain and morbidity had been unresolved by conservative treatment. Adverse events including infection, revisions, and evidence of immune response were evaluated and patient comorbidities defined for the entire population of patients. Patient fusion status was assessed using thin slice CT by 2 independent radiologists separate from the surgeon. There were 75 consecutive adult patients with degenerative conditions of the lumbar spine who underwent MIS-TLIF surgery of which 40 (53%) were male and 35 (47%) were female. Mean age, height, and weight were 58 years, 170.18 cm (67 in), and 88.45 kg (195 lbs), respectively. The mean body mass index was 30. There were 16 patients (21%) who smoked and 12 (16%) with a history of diabetes. Independent blinded review of fusion was obtained by a board certified musculoskeletal radiologist and an experienced board certified orthopaedic surgeon to assess patient fusion status. Spinal segments were deemed fused if 12-month CT scans demonstrated evidence of bridging bone at the fusion site without observed motion on flexion-extension radiographs. Findings such as osteolysis around the implant or pedicle screws, extensive endplate cystic changes, or linear defects parallel to the endplates through intradiscal new bone formation were interpreted as signs of pseudarthrosis. Interobserver and intraobserver error and κ assessments were analyzed to assure agreement in the CT outcomes assessment where interpretation of κ were as follows: <0.00 = poor agreement, 0.00-0.20 = slight agreement, 0.21-0.40 = fair agreement, 0.41-0.60 = moderate agreement, 0.61-0.80 = substantial agreement, and 0.81-1.00 = almost perfect agreement. Differences were resolved by consensus amongst the observers.

Results

In total, 96% of the 75 patients with a total of 85 levels (96.5% of levels treated) achieved a fusion at 12 months. There were no perioperative or latent complications and no transfusions in all 75 patients.

Conclusions

In this population, 96% of the patients treated achieved the surgical objective in 96.5% of the levels treated.

Level of Evidence

IV.

Clinical Relevance

The high rate of fusion, the lack of secondary morbidity with autologous bone harvest, and the clinical success account for the benefits of viable allograft matrix for MIS-TLIF use.

Comparison of the Total and Hidden Blood Loss in Patients Undergoing Open and Minimally Invasive Transforaminal Lumbar Interbody Fusion

PURPOSE

This study examined the volume of hidden blood loss (HBL) and compared perioperative blood loss between minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) and open transforaminal lumbar interbody fusion (O-TLIF).

METHODS

Forty-eight patients who were treated with MI-TLIF and 59 patients treated with O-TLIF were enrolled in this study. Patients' height, weight, and preoperative and postoperative hematocrit (Hct) were recorded and used to calculate total blood loss (TBL) according to the Gross formula. Each patient's HBL was calculated. The data were further analyzed by the Student t test and the χ² test.

RESULTS

The visible blood loss (VBL) was 186 ± 95 mL in the MI-TLIF; however, the HBL (423 ± 233 mL; 66.5 ± 16.1% of TBL) was twice the VBL. The VBL in the O-TLIF group was 471 ± 147 mL, and the HBL was 271 ± 223 mL (31.3 ± 23.9% of TBL). Although TBL in MI-TLIF (602 ± 251 mL) was less than in O-TLIF (742 ± 275 mL), the HBL was significantly higher (P < 0.01). No difference in postoperative blood loss was observed between the 2 groups. Seven and 10 patients had preoperative anemia in the MI-TLIF group and the O-TLIF group, respectively, and 32 and 45 postoperatively.

CONCLUSION

HBL is seriously underestimated and accounts for a large percentage of TBL in both MI-TLIF and O-TLIF. A correct understanding of HBL can ensure patient safety and improve postoperative rehabilitation.