The analysis of percutaneous pedicle screw technique with guide wire-less in lateral decubitus position following extreme lateral interbody fusion

Single-position oblique lumbar interbody fusion with navigation: improved efficiency and screw accuracy compared to dual-position with fluoroscopy

Dual-position oblique lumbar interbody fusion with fluoroscopy (D-OLIF) requires repositioning the patient to a prone position for pedicle screw insertion. Recently, single-position surgery with navigation has been introduced. However, there are concerns regarding pedicle screw accuracy and achieving appropriate sagittal balance in single-position OLIF with navigation (S-OLIF). The purpose of this study is to evaluate the clinical and radiological outcomes of S-OLIF compared to D-OLIF. A retrospective analysis was conducted on 102 patients who underwent single-level OLIF at a single institution. The patients were divided into two groups: 55 in the S-OLIF group and 47 in the D-OLIF group. The numeric rating scale for back and leg, Oswestry disability index, and walking distance improvements showed no significant difference. However, the EuroQol 5-dimension 5-level index showed higher improvement in the S-OLIF (P = 0.029). The segmental lordosis, lumbar lordosis, and C7 sagittal vertical axis showed no significant difference. S-OLIF had significantly fewer cases of pedicle screw malposition (P = 0.045). Additionally, the surgery time was shorter in the S-OLIF (P = 0.002). In conclusion, S-OLIF exhibited clinical and radiological outcomes comparable to D-OLIF, with the added advantages of reduced surgery time and enhanced accuracy in pedicle screw placement.

Biomechanical effects of posterior lumbar interbody fusion with vertical placement of pedicle screws compared to traditional placement

BACKGROUND

The pedicle screw technique is widely employed for vertebral body fixation in the treatment of spinal disorders. However, traditional screw placement methods require the dissection of paraspinal muscles and the insertion of pedicle screws at specific transverse section angles (TSA). Larger TSA angles require more force to pull the muscle tissue, which can increase the risk of surgical trauma and ischemic injury to the lumbar muscles.

AIM

To study the feasibility of zero-degree TSA vertical pedicle screw technique in the lumbosacral segment.

METHODS

Finite element models of vertebral bodies and pedicle screw-rod systems were established for the L4-S1 spinal segments. A standard axial load of 500 N and a rotational torque of 10 N/m were applied. Simulated screw pull-out experiment was conducted to observe pedicle screw resistance to pull-out, maximum stress, load-displacement ratio, maximum stress in vertebral bodies, load-displacement ratio in vertebral bodies, and the stress distribution in pedicle screws and vertebral bodies. Differences between the 0-degree and 17-degree TSA were compared.

RESULTS

At 0-degree TSA, the screw pull-out force decreased by 11.35% compared to that at 17-degree TSA (P < 0.05). At 0-degree and 17-degree TSA, the stress range in the screw-rod system was 335.1-657.5 MPa and 242.8-648.5 MPa, separately, which were below the fracture threshold for the screw-rod system (924 MPa). At 0-degree and 17-degree TSA, the stress range in the vertebral bodies was 68.45-78.91 MPa and 39.08-72.73 MPa, separately, which were below the typical bone yield stress range for vertebral bodies (110-125 MPa). At 0-degree TSA, the load-displacement ratio for the vertebral bodies and pedicle screws was slightly lower compared to that at 17-degree TSA, indicating slightly lower stability (P < 0.05).

CONCLUSION

The safety and stability of 0-degree TSA are slightly lower, but the risks of screw-rod system fracture, vertebral body fracture, and rupture are within acceptable limits.

Short-Term Comparison Between Unilateral Versus Bilateral Percutaneous Pedicle Screw Fixation in Short-Level Lateral Lumbar Interbody Fusion-A Prospective Randomized Study

STUDY DESIGN

Prospective randomized controlled trial.

OBJECTIVES

No prospective studies have directly compared clinical and radiographic outcomes of unilateral vs bilateral instrumented lateral lumbar interbody fusion (LLIF) for lumbar degenerative disease (LDD). We compared the short-term radiographic, clinical outcomes, and some complications of the unilateral percutaneous pedicle screw (PPS) (UPS) vs bilateral PPS (BPS) fixation in short-level spinal fusion with LLIF for LDD.

METHODS

This was a prospective randomized controlled study of 33 patients who underwent UPS or BPS fixation after LLIF for LDD; 18 patients were assigned to the UPS group and 15 patients to the BPS group. Clinical outcomes, complication rates, and fusion rates were assessed.

RESULTS

The two groups were similar in age, sex, preoperative diagnosis, and level of surgery. Blood loss, length of hospital stay, and numeric rating scale score one year after surgery did not differ between groups. The operative time was longer in the BPS than UPS group (120.2 vs 88.8 min, respectively; P = .029). Both groups showed improvement in disc height and dural sac in the immediate postoperative computed tomography and magnetic resonance imaging, which did not differ significantly between groups. The subsidence grade and fusion rate did not differ, but cage subsidence was more severe in the UPS than BPS group.

CONCLUSION

Unilateral and bilateral PPS fixation after LLIF yielded similar short-term clinical and radiological outcomes. However, severe cage subsidence was more common in the UPS group, which suggests that BPS fixation after LLIF may be a better choice over the long term.

Quantifying Satisfaction of Degenerative Lumbar Spinal Stenosis Patients in Post-lateral Lumbar Interbody Fusion Surgery: Establishing Critical JOABPEQ Cutoff Scores

OBJECTIVE

This retrospective study aimed to determine the Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ) cutoff scores for assessing patient satisfaction postlateral lumbar interbody fusion (LLIF) in degenerative lumbar spinal stenosis (DLSS) patients.

METHODS

Analyzing 136 DLSS patients (83 males, 53 females), the study evaluated demographics, pain (Numeric Rating Scale), and JOABPEQ outcomes (low back pain, lumbar function, walking ability, social life, mental health). Patient satisfaction was surveyed, and based on their responses, patients were categorized into "Beneficial" and "Nonbeneficial" groups. Statistical analysis encompassed the Kolmogorov-Smirnov test, t-tests, Mann-Whitney U test, and Receiver Operating Characteristic (ROC) curve analysis for JOABPEQ cutoff determination.

RESULTS

Postoperative improvements in JOABPEQ scores, especially in walking ability, social life function, and mental health, were significant. Pain intensity, assessed using the Numeric Rating Scale, also showed notable reductions. The Δ walking ability cutoff was set at 25.00, indicating substantial mobility improvement. This domain's area under the curve (AUC) was 0.815 (95% CI: 0.726-0.903), demonstrating high effectiveness in assessing patient satisfaction postsurgery. The study also found no significant differences in complication rates between groups for conditions like transient motor weakness, thigh pain/numbness, and revision surgery.

CONCLUSIONS

This study underscores the value of patient-centered outcomes in evaluating LLIF surgery success for DLSS. The identified JOABPEQ cutoff values provide a quantitative tool for assessing patient satisfaction, emphasizing the necessity of comprehensive postoperative evaluations beyond traditional clinical metrics for improved patient care and life quality.

Advancing Prone-Transpsoas Spine Surgery: A Narrative Review and Evolution of Indications with Representative Cases

The Prone Transpsoas (PTP) approach to lumbar spine surgery, emerging as an evolution of lateral lumbar interbody fusion (LLIF), offers significant advantages over traditional methods. PTP has demonstrated increased lumbar lordosis gains compared to LLIF, owing to the natural increase in lordosis afforded by prone positioning. Additionally, the prone position offers anatomical advantages, with shifts in the psoas muscle and lumbar plexus, reducing the likelihood of postoperative femoral plexopathy and moving critical peritoneal contents away from the approach. Furthermore, operative efficiency is a notable benefit of PTP. By eliminating the need for intraoperative position changes, PTP reduces surgical time, which in turn decreases the risk of complications and operative costs. Finally, its versatility extends to various lumbar pathologies, including degeneration, adjacent segment disease, and deformities. The growing body of evidence indicates that PTP is at least as safe as traditional approaches, with a potentially better complication profile. In this narrative review, we review the historical evolution of lateral interbody fusion, culminating in the prone transpsoas approach. We also describe several adjuncts of PTP, including robotics and radiation-reduction methods. Finally, we illustrate the versatility of PTP and its uses, ranging from 'simple' degenerative cases to complex deformity surgeries.

Comparison of standard and modified prone positioning for lateral lumbar spine fusion: a feasibility study to reduce lumbar plexus injury

Single-prone-lateral (PL) positioning is a new technique that allows for simultaneous anterior and posterior lumbar spine surgery. However, there is a concern regarding the risk of lumbar plexus injury in PL positioning. This study compared the risk of lumbar plexus damage and the overall safety profile of a modified PL (mPL) position to the standard PL (sPL) position for lateral lumbar spine fusion surgery. A crossover soft cadaveric study was conducted with two raters examining the comparative outcomes of position A: sPL and position B: mPL. The mPL position differs from the sPL position in that the ipsilateral arm is placed at the side of the body rather than above the head. To assess positive results (no lumbar plexus injury) between positions A and B, a mixed effects logistic regression model was utilized. The odds ratio of a good result between positions B and A was also determined. The odds ratio of the favorable outcome between position B and A was 1.77, indicating significantly higher odds of a favorable outcome in the modified position B than in the control or position A. The mPL positioning outperformed the sPL positioning in terms of safety and efficacy for lateral lumbar spine fusion. The mPL positioning may reduce the risk of lumbar plexus injury by allowing for a more direct approach to the lumbar spine and by avoiding excessive stretching of the lumbar plexus.

The Influence of Screw Positioning on Cage Subsidence in Patients with Oblique Lumbar Interbody Fusion Combined with Anterolateral Fixation

OBJECTIVES

Cage subsidence (CS) has been reported to be one of the most common complications following oblique lumbar interbody fusion (OLIF). To reduce the incidence of CS and improve intervertebral fusion rates, anterolateral fixation (AF) has been gradually proposed. However, the incidence of CS in patients with oblique lumbar interbody fusion combined with anterolateral fixation (OLIF-AF) is still controversial. Additionally, there is a lack of consensus regarding the optimal placement of screws for OLIF-AF, and the impact of screw placement on the incidence of CS has yet to be thoroughly investigated and validated. The objective of this investigation was to examine the correlation between screw placements and CS and to establish an optimized approach for implantation in OLIF-AF.

METHODS

A retrospective cohort study was undertaken. From October 2017 to December 2020, a total of 103 patients who received L4/5 OLIF-AF for lumbar spinal stenosis or spondylolisthesis or degenerative instability in our department were followed up for more than 12 months. Demographic and radiographic data of these patients were collected. Additionally, screw placement related parameters, including trajectory and position, were measured by anterior-posterior X-ray and axial CT. Analysis was done by chi-square, independent t-test, univariable and multivariable binary logistic regression to explore the correlation between screw placements and CS. Finally, the receiver operating characteristic (ROC) curve analysis was used to evaluate the predictive ability of screw placement-related parameters.

RESULTS

A total of 103 patients were included, and CS was found in 28 (27.18%) patients. Univariable analysis was firstly performed for each parameter. Next, variables with p-value of <0.05, including bone mineral density (BMD), concave morphology, and screw placement-related parameters were included in the multivariate logistic regression analysis. Significant predictor factors for subsidence were coronal plane angle (CPA) (OR 0.580 ± 0.208, 95% CI 1.187-2.684), implantation point (IP) (L4) (OR 5.732 ± 2.737, 95% CI 1.445-12.166), and IP (L5) (OR 7.160 ± 3.480, 95% CI 1.405-28.683). Furthermore, ROC curves showed that the predictive accuracy of CS was 88.1% for CPA, 77.6% for IP (L4) and 80.9% for IP (L5).

CONCLUSIONS

We demonstrate that the trajectory of vertebral screws, including angle and position, was closely related to CS. Inserting screws parallel to each other and as close to the endplate as possible while keeping the cage inside the range of the superior and inferior screws are an optimal implantation strategy for OLIF-AF.

Assessing Procedural Accuracy in Lateral Spine Surgery: A Retrospective Analysis of Percutaneous Pedicle Screw Placement with Intraoperative CT Navigation

Percutaneous pedicle screws (PPSs) are commonly used in posterior spinal fusion to treat spine conditions such as trauma, tumors, and degenerative diseases. Precise PPS placement is essential in preventing neurological complications and improving patient outcomes. Recent studies have suggested that intraoperative computed tomography (CT) navigation can reduce the dependence on extensive surgical expertise for achieving accurate PPS placement. However, more comprehensive documentation is needed regarding the procedural accuracy of lateral spine surgery (LSS). In this retrospective study, we investigated patients who underwent posterior instrumentation with PPSs in the thoracic to lumbar spine, utilizing an intraoperative CT navigation system, between April 2019 and September 2023. The system's methodology involved real-time CT-based guidance during PPS placement, ensuring precision. Our study included 170 patients (151 undergoing LLIF procedures and 19 trauma patients), resulting in 836 PPS placements. The overall PPS deviation rate, assessed using the Ravi scale, was 2.5%, with a notably higher incidence of deviations observed in the thoracic spine (7.4%) compared to the lumbar spine (1.9%). Interestingly, we found no statistically significant difference in screw deviation rates between upside and downside PPS placements. Regarding perioperative complications, three patients experienced issues related to intraoperative CT navigation. The observed higher rate of inaccuracies in the thoracic spine suggests that various factors may contribute to these differences in accuracy, including screw size and anatomical variations. Further research is required to refine PPS insertion techniques, particularly in the context of LSS. In conclusion, this retrospective study sheds light on the challenges associated with achieving precise PPS placement in the lateral decubitus position, with a significantly higher deviation rate observed in the thoracic spine compared to the lumbar spine. This study emphasizes the need for ongoing research to improve PPS insertion techniques, leading to enhanced patient outcomes in spine surgery.

Minimally Invasive Approach for Degenerative Spondylolisthesis: Lateral Single-Position Surgery with Intraoperative Computed Tomography Navigation and Fluoroscopy: A Technical Note

OBJECTIVE

Degenerative spondylolisthesis (DS) is a prevalent condition that leads to low back pain and neurological symptoms. This technical note presents a novel surgical strategy for treating DS using lateral single-position surgery (SPS) in combination with intraoperative computed tomography navigation and fluoroscopy.

METHODS

Fifteen patients (5 males and 10 females, mean age 70.2 years) diagnosed with DS with a slip of 5 mm or more underwent lateral lumbar interbody fusion (LLIF) with percutaneous pedicle screw (PPS) fixation using this technique. The procedure involved slip reduction using an upside PPS and rod fixation, followed by LLIF performed in the same lateral position. The term "upside PPS" refers to a PPS that is inserted on the ceiling side of the patient's surgical field. Preoperative and postoperative radiographic assessments were conducted to evaluate the effectiveness of the lateral SPS.

RESULTS

The results demonstrated significant improvements in various parameters, including spondylolisthesis reduction, segmental lordosis, disc height, and spinal canal dimensions. The lateral-SPS procedure exhibited several advantages over traditional flip LLIF approaches for slip reduction. Additionally, the technique provided accurate intraoperative navigation guidance through computed tomography imaging, ensuring precise implant placement and slip reduction.

CONCLUSIONS

Combining LLIF and PPS fixation in a single procedure presents a precise, efficient approach for DS treatment, minimizing repositioning needs. This technique enables effective lumbar reconstruction, restoration of spinal stability, and improved patient outcomes. Although further investigation is warranted, lateral SPS surgery may hold promise as an innovative solution for managing DS by reducing surgical invasiveness and optimizing surgical efficiency.

Early Radiological Assessment of Static and Expandable Cages in Lateral Single Position for Indirect Decompression- Lateral Lumbar Interbody Fusion

OBJECTIVE

This study aimed to compare the postoperative alignment of static and expandable cages in lateral single-position (LSP) for indirect decompression in lateral lumbar interbody fusion (LLIF).

METHODS

We included sixty-seven patients who underwent LSP-LLIF for lumbar degenerative disease. We performed radiological assessments preoperatively and two weeks postoperatively using computed tomography and magnetic resonance imaging. We divided the patients into the expandable cage group (23 patients) and the static cage group (44 patients). We measured disc height (DH), segmental lordosis (SL), and foraminal area (FA) from computed tomography images and the area of the dural sac from magnetic resonance imaging. We recorded surgical outcomes and complications.

RESULTS

Both static and expandable cages demonstrated improvements in DH, SL, FA, and dural sac expansion. However, we found no statistically significant differences in the average change in DH (4.4 ± 2.1 mm vs. 4.2 ± 1.8 mm, P = 0.685), the average change in SL (1.0 ± 4.4° vs. 1.9 ± 3.6°, P = 0.310), or FA change (32.5 ± 31.7 mm2 vs. 34.9 ± 29.5 mm2, P = 0.966) between the expandable and static cage groups. We also found no statistically significant difference in dural sac enlargement between the two groups. We observed no significant differences in operation time, estimated blood loss, or length of hospital stay between the two groups. No severe adverse events or additional surgeries were reported.

CONCLUSIONS

In LSP-LLIF without facet joint resection or other posterior techniques, static and expandable cages showed comparable effectiveness in achieving increased DH, SL, FA, and indirect decompression.

Comprehensive Assessment of Indirect Decompression Through Lateral Lumbar Interbody Fusion for Degenerative Lumbar Spinal Stenosis: A Japanese Orthopedic Association Back Pain Evaluation Questionnaire-Based Analysis

STUDY DESIGN

A retrospective study.

OBJECTIVE

This study aimed to comprehensively evaluate the clinical outcomes of lateral lumbar interbody fusion (LLIF) as an indirect decompression technique for degenerative spondylolisthesis (DS) and concomitant degenerative lumbar spinal stenosis (DLSS) patients. We utilized the Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ) to assess treatment success and its impact on patient's quality of life (QOL).

METHODS

We included 124 patients who underwent LLIF. Pre- and postoperative JOABPEQ evaluations indicated treatment success. Subgroup analysis categorized patients' perceptions of surgery as beneficial or non-beneficial.

RESULTS

89% of patients (110/124) reported satisfaction with LLIF. Lateral lumbar interbody fusion achieved successful indirect decompression, increasing canal diameter and central canal area. Significant improvements occurred across all JOABPEQ domains, notably for low back pain, lumbar function, walking ability, social life function, and mental health. Patients who perceived the surgery as beneficial experienced fewer postoperative complications, lower numeric rating scale scores for pain relief, and greater functional outcome improvements compared to non-beneficial patients.

CONCLUSIONS

Our findings highlight the utility of JOABPEQ as a valuable and sensitive tool for assessing treatment effectiveness and patient-reported outcomes in DS and concomitant DLSS patients. Patients undergoing LLIF. The results affirm the favorable outcomes of LLIF as a surgical option for DLSS patients and emphasize the importance of considering patient perspectives when evaluating overall treatment success. The study provides valuable insights into the impact of indirect decompression on patients' QOL, supporting the effectiveness of LLIF as a minimally invasive technique for DLSS and DS management.

Minimally invasive lateral single-position surgery for multilevel degenerative lumbar spine disease: feasibility and perioperative results in a single Latin-American spine center

INTRODUCTION

Within advances in minimally invasive spine surgery, the implementation of lateral single position (LSP) increases efficiency while limiting complications, avoiding intraoperative repositioning and diminishing surgical time. Most literature describes one-level instrumentation of the lumbar spine; this study includes the use of LSP for multilevel degenerative disease.

OBJECTIVE

The objective of the article is to analyze initial clinical results and complications in the use of LSP for multiple level instrumentation in adults with lumbar degenerative disease.

METHODS

A retrospective early clinical series was performed for patients who had multiple level instrumentation in LSP between August 2019 and September 2022 at the Hospital Universitario San Ignacio in Bogota, Colombia. Inclusion criteria were patients older than 18 years with symptomatic lumbar degenerative disease, undergoing any combination of multilevel anterior lumbar interbody fusion, lateral lumbar interbody fusion (LLIF) and pedicle screw fixation.

RESULTS

Forty patients with an average age of 61.3 years were included, with diagnosis of multilevel degenerative spondylotic changes. Four-, three- and two-level interventions were performed in 52.5, 35 and 12.5%, respectively. Average time per level was 68.9 min, and length of hospital stay had an average of 2.4 days, with all patients starting ambulation within the first postoperative day.

CONCLUSION

Procedural time and blood loss were similar to those reported in literature. No severe lesions, postoperative infections or reinterventions took place. Although it was a small number of patients and further clinical trials are needed, LSP for multiple levels is apparently safe with adequate outcomes which may improve efficiency in the operating room.

Single-Position Oblique Lumbar Interbody Fusion and Percutaneous Pedicle Screw Fixation under O-Arm Navigation: A Retrospective Comparative Study

The insertion of pedicle screws in the lateral position without a position change has been reported. We completed a retrospective comparison of the radiologic and clinical outcomes of 36 patients who underwent either single-position oblique lateral lumbar interbody fusion (SP-OLIF) using the O-arm (36 cases) or conventional OLIF (C-OLIF) using the C-arm (20 cases) for L2-5 single-level lumbar degenerative diseases. Radiological parameters were analyzed, including screw accuracy (Gertzbein-Robbins classification system; GRS), segmental instability, and fusion status. Screw misplacement was defined as a discrepancy of ≥2 mm. Clinical outcomes, including visual analog scale, Oswestry Disability Index (ODI), 36-Item Short Form Health Survey (SF-36), and postoperative complications, were assessed. The spinal fusion rate was not different between the SP-OLIF and C-OLIF groups one year after surgery (p = 0.536). The ODI score was lower (p = 0.015) in the SP-OLIF than the C-OLIF group. Physical (p = 0.000) and mental component summaries (p = 0.000) of the SF-36 were significantly higher in the SP-OLIF group. Overall complication rates, including revision, surgical site infection, ipsilateral weakness, and radicular pain/numbness, were not significantly different. SP-OLIF using the O-arm procedure is feasible, with acceptable accuracy, fusion rate, and complication rate. This may be an alternative to conventional two-stage operations.

Treatment of Lumbar Degenerative Disease by Lateral Lumbar Interbody Fusion in Patients Under and Over 80 Years of Age

OBJECTIVES

The purpose of this study was to compare clinical and radiological results of lateral lumbar interbody fusion (LLIF) for lumbar degenerative disease in patients under the age of 80 years with those over the age of 80 years.

METHODS

One hundred two patients who underwent LLIF without direct decompression were enrolled, including 92 patients who were less than 80 years (group A) and 10 over 80 years (group B). All patients were evaluated using numerical evaluation scale scores for low back pain, leg pain, and leg numbness, as well as demographic data, surgical data, and imaging data before and after LLIF surgery.

RESULTS

Patients over the age of 80 years were found to have longer hospital stays (P = 0.006) and more postoperative muscle weakness (P = 0.011) and endplate injuries (P = 0.038). In addition, each numerical evaluation scale score improved significantly from preoperative to postoperative (P < 0.001). However, the changes in scores between preoperative and postoperative for each numerical evaluation scale were not significantly different between the 2 groups. Statistically significant increases in lumbar lordosis preoperatively compared with postoperatively were observed in patients under 80 years but did not change in those over 80 years.

CONCLUSIONS

These data suggest a need for awareness of intraoperative endplate injury and postoperative motor weakness. Critically, indirect decompression with LLIF in lumbar degenerative disease in patients over age 80 as well as those under age 80 has shown satisfactory clinical and radiological results. This study shows that age alone should not prevent older people from undergoing LLIF.

Lumbar plexus safe working zones with lateral lumbar interbody fusion: a systematic review and meta-analysis

PURPOSE

Significant risk of injury to the lumbar plexus and its departing motor and sensory nerves exists with lateral lumbar interbody fusion (LLIF). Several cadaveric and imaging studies have investigated the lumbar plexus position with respect to the vertebral body anteroposterior plane. To date, no systematic review and meta-analysis of the lumbar plexus safe working zones for LLIF has been performed.

METHODS

This systematic review was conducted according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Relevant studies reporting on the position of the lumbar plexus with relation to the vertebral body in the anteroposterior plane were identified from a PubMed database query. Quantitative analysis was performed using Welch's t test.

RESULTS

Eighteen studies were included, encompassing 1005 subjects and 2472 intervertebral levels. Eleven studies used supine magnetic resonance imaging (MRI) with in vivo subjects. Seven studies used cadavers, five of which performed dissection in the left lateral decubitus position. A significant correlation (p < 0.001) existed between anterior lumbar plexus displacement and evaluation with in vivo MRI at all levels between L1-L5 compared with cadaveric measurement. Supine position was also associated with significant (p < 0.001) anterior shift of the lumbar plexus at all levels between L1-L5.

CONCLUSIONS

This is the first comprehensive systematic review and meta-analysis of the lumbar neural components and safe working zones for LLIF. Our analysis suggests that the lumbar plexus is significantly displaced ventrally with the supine compared to lateral decubitus position, and that MRI may overestimate ventral encroachment of lumbar plexus.

Single-position anterior and lateral lumbar fusion in the supine position: a novel technique for multi-level arthrodesis

OBJECTIVE

Anterior lumbar interbody fusion (ALIF) and lateral lumbar interbody fusion (LLIF) are common techniques that typically require staged procedures when performed in combination. Interest is emerging in single-position surgery to increase operative efficiency. We report a novel surgical technique, supine extended reach (SupER) lateral fusion, to perform ALIF and LLIF with the patient in a single supine position.

METHODS

A man in his fifties presented with degenerative levoscoliosis, spondylolisthesis, sagittal-plane deformity, and progressive low back pain. He was offered L3-S1 anterolateral fusion.

RESULTS

With the patient supine, a left abdominal paramedian incision was performed to gain anterior retroperitoneal access, and standard L5-S1 and L4-5 ALIFs were performed. The anterior incision was used for direct visualization, retraction, and bimanual dissection. A left lateral incision was then made to perform an L3-4 LLIF. The patient subsequently underwent a second-stage L3-S1 posterior percutaneous fixation. The patient tolerated the procedures well, without complications. Postoperative radiograph findings confirmed acceptable implant positioning. The patient was discharged home in stable condition and was doing well at follow-up.

CONCLUSION

This case description is the first report of the SupER technique, which allows incorporation of anterior and lateral fusion constructs at adjacent levels without changing patient positioning. Many surgeons believe the ALIF to be the most powerful technique for achieving lordosis, and this technique enables concomitant lateral access in a supine position. It can also be used as an alternative strategy when anterior access to the disc space is unobtainable. Further clinical investigation of this technique is warranted.

Perioperative and Radiographic Outcomes Between Single-Position Surgery (Lateral Decubitus) and Dual-Position Surgery for Lateral Lumbar Interbody Fusion and Percutaneous Pedicle Screw Fixation: Meta-Analysis

OBJECTIVE

Lateral lumbar interbody fusion (LLIF) and percutaneous posterior screw fixation (PPSF) techniques is used to treat degenerative lumbar pathologies. Dual-position (DP) lumbar surgery involves repositioning the patient from the supine or lateral decubitus position to prone for posterior fixation. Single-position (SP) lumbar surgery is commonly performed nowadays, a minimally invasive alternative performed entirely from the lateral decubitus position. However, controversy still exists. This meta-analysis aimed to compare perioperative outcomes between SP lumbar surgery and DP lumbar surgery for LLIF and PPSF.

METHODS

We conducted this meta-analysis according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and searched Medline and Scopus from inception to November 11, 2021, for relevant studies.

RESULTS

Six studies were identified, which contained totals of 502 and 447 patients in the SP and DP groups, respectively. The unstandardized mean difference in operative time, length of hospital stay, intraoperative blood loss, radiation doses, lumbar lordosis, and pelvic incidence-lumbar lordosis mismatch were -86.1 (95% confidence interval [CI] -149.2 to -23.1) minutes, -1.6 (95% CI -2.4 to -0.9) days, -55.6 (95% CI -127.5 to 16.2) mL, -30.3 (95% CI -80.5 to 19.8) mGy, 1.34 (95% CI -1.17 to 3.86) degrees, and -4.06 (95% CI -5.65 to -2.47) lower in SP when compared with DP. The chances of having complications and reoperations in SP were 0.75 (95% CI 0.49-1.14) and 0.77 (95% CI 0.44-1.36) times, respectively, compared with the DP group. No significant differences were found for intraoperative blood loss, radiation dose, lumbar lordosis, complications, and reoperations between the 2 groups.

CONCLUSIONS

This meta-analysis found that SP have lower operative time and length of hospital stay compared with DP LLIF and PPSF. However, no differences in intraoperative blood loss, radiation dose, radiographic change, complications, and reoperation rates were found.

Lateral versus prone robot-assisted percutaneous pedicle screw placement: a CT-based comparative assessment of accuracy

OBJECTIVE

Single-position lateral lumbar interbody fusion (SP-LLIF) has recently gained significant popularity due to increased operative efficiency, but it remains technically challenging. Robot-assisted percutaneous pedicle screw (RA-PPS) placement can facilitate screw placement in the lateral position. The authors have reported their initial experience with SP-LLIF with RA-PPS placement in the lateral position, and they have compared this accuracy with that of RA-PPS placement in the prone position.

METHODS

The authors reviewed prospectively collected data from their first 100 lateral-position RA-PPSs. The authors graded screw accuracy on CT and compared it to the accuracy of all prone-position RA-PPS procedures during the same time period. The authors analyzed the effect of several demographic and perioperative metrics, as a whole and specifically for lateral-position RA-PPS placement.

RESULTS

The authors placed 99 lateral-position RA-PPSs by using the ExcelsiusGPS robotic platform in the first 18 consecutive patients who underwent SP-LLIF with postoperative CT imaging; these patients were compared with 346 prone-position RA-PPSs that were placed in the first consecutive 64 patients during the same time period. All screws were placed at L1 to S1. Overall, the lateral group had 14 breaches (14.1%) and the prone group had 25 breaches (7.2%) (p = 0.032). The lateral group had 5 breaches (5.1%) greater than 2 mm (grade C or worse), and the prone group had 4 (1.2%) (p = 0.015). The operative level had an effect on the breach rate, with breach rates (grade C or worse) of 7.1% at L3 and 2.8% at L4. Most breaches were grade B (< 2 mm) and lateral, and no breach had clinical sequelae or required revision. Within the lateral group, multivariate regression analysis demonstrated that BMI and number of levels affected accuracy, but the side that was positioned up or down did not.

CONCLUSIONS

RA-PPSs can improve the feasibility of SP-LLIF. Spine surgeons should be cautious and selective with this technique owing to decreased accuracy in the lateral position, particularly in obese patients. Further studies should compare SP-LLIF techniques performed while the patient is in the prone and lateral positions.

Transitioning from lateral to the prone transpsoas approach: flatten the learning curve by knowing the nuances

Prone transpsoas lateral lumbar interbody fusion is the newest frontier in surgical approach to the lumbar spine. Prone positioning facilitates segmental lordosis and facile posterior segmental fixation. However, even in experienced hands, transitioning from a lateral decubitus to prone position necessitates alterations to the traditional technique. In this video, the authors highlight the nuances of adopting the prone transpsoas lateral lumbar interbody fusion technique and strategies to overcome them.

The video can be found here: https://stream.cadmore.media/r10.3171/2022.3.FOCVID2224

Efficacy of Single-Position Oblique Lateral Interbody Fusion Combined With Percutaneous Pedicle Screw Fixation in Treating Degenerative Lumbar Spondylolisthesis: A Cohort Study

Objective

To investigate the surgical outcomes of single-position oblique lateral interbody fusion (OLIF) combined with percutaneous pedicle screw fixation (PPSF) in treating degenerative lumbar spondylolisthesis (DLS).

Methods

We retrospectively analyzed 85 patients with DLS who met the inclusion criteria from April 2018 to December 2020. According to the need to change their position during the operation, the patients were divided into a single-position OLIF group (27 patients) and a conventional OLIF group (58 patients). The operation time, intraoperative blood loss, hospitalization days, instrumentation accuracy and complication rates were compared between the two groups. The visual analog scale (VAS) and Oswestry Disability Index (ODI) were used to evaluate the clinical efficacy. The surgical segment's intervertebral space height (IDH) and lumbar lordosis (LL) angle were used to evaluate the imaging effect.

Results

The hospital stay, pedicle screws placement accuracy, and complication incidence were similar between the two groups (P > 0.05). The operation time and intraoperative blood loss in the single-position OLIF group were less than those in the conventional OLIF group (P < 0.05). The postoperative VAS, ODI, IDH and LL values were significantly improved (P < 0.05), but there was no significant difference between the two groups (P > 0.05).

Conclusions

Compared with conventional OLIF, single-position OLIF combined with PPSF is also safe and effective, and it has the advantages of a shorter operation time and less intraoperative blood loss.

The Mini-Open Wiltse Approach with Pedicle Screw Fixation Versus Percutaneous Pedicle Screw Fixation for Treatment of Neurologically Intact Thoracolumbar Fractures: A Systematic Review and Meta-Analysis

OBJECTIVE

The purpose of the present study was to compare the clinical outcomes and complications between the mini-open Wiltse approach with pedicle screw fixation (MWPSF) and percutaneous pedicle screw fixation (PPSF) in treating neurologically intact thoracolumbar fractures.

METHODS

We comprehensively searched PubMed, Web of Science, Embase, and the Cochrane Library and performed a systematic review and meta-analysis of all randomized controlled trials and retrospective comparative studies assessing these important indexes of the 2 methods using Review Manager, version 5.4. The clinical outcomes are presented as the risk difference for dichotomous outcomes and the mean difference for continuous outcomes with the 95% confidence intervals. Heterogeneity was assessed using the χ² test and I² statistics. The study was registered with PROSPERO (CRD 42021290078).

RESULTS

Two randomized controlled trials and six retrospective cohort studies were included in the present analysis. The percutaneous approach was associated with less intraoperative blood loss compared with the mini-open Wiltse approach. No significant differences were found in the total length of the incisions, hospitalization time, postoperative visual analog scale scores, postoperative Oswestry disability index, postoperative Cobb angle, postoperative Cobb angle correction, postoperative Cobb angle correction loss, accuracy rate of pedicle screw placement, and postoperative complications between MWPSF and PPSF. However, the incidence of facet joint violation was significantly higher in the PPSF group. In addition, MWPSF was associated with a shorter operative time, shorter intraoperative fluoroscopy time, lower hospitalization costs, better postoperative vertebral body angle and percentage of vertebral body height compared with PPSF.

CONCLUSIONS

Both MWPSF and PPSF are safe and effective treatments of neurologically intact thoracolumbar fractures. Nevertheless, our results have indicated that MWPSF might be the better choice, because it has a shorter learning curve and decreased facet joint violation, operative time, hospitalization costs, and radiation exposure. In addition, MWPSF was associated with better improvement of the postoperative vertebral body angle and percentage of vertebral body height.

The Effect of Preoperative Neuropathic Pain and Nociceptive Pain on Postoperative Pain Intensity in Patients with the Lumbar Degenerative Disease Following Lateral Lumbar Interbody Fusion

OBJECTIVE

The purpose of this study was to analyze whether the type of preoperative pain affects the improvement in postoperative pain intensity in patients with a lumbar degenerative disease (LDD).

METHODS

We retrospectively reviewed 93 patients who underwent lateral lumbar interbody fusion (LLIF) without direct decompression. All patients were evaluated using Numeric Rating Scale (NRS) scores for low back pain (NRS_LBP), leg pain (NRS_LP), and leg numbness (NRS_LN) and imaging data before and after LLIF surgery. Based on the Japanese version of the painDETECT scores, patients were classified into 3 groups: a neuropathic pain (NeP) group, a nociceptive pain (NocP) group, and an intermediate mixed pain group.

RESULTS

The Japanese version of the painDETECT identified NeP in 20.4% of patients with LDD prior to LLIF. Preoperative NRS_LBP, NRS_LP, and NRS_LN scores were higher in the NeP group than those in the NocP group. All types of pain improved after LLIF surgery. The NRS_LBP score 12 months after surgery was higher in the NeP group (3.8 ± 2.8) than that in the NocP group (1.9 ± 2.2) (P = 0.008). Similar results were obtained with NRS_LP (NeP group = 3.1 ± 2.8, NocP group = 1.5 ± 2.0, P = 0.010).

CONCLUSIONS

Although LLIF was useful for relieving all types of preoperative pain in LDD patients, the NRS scores for preoperative pain were higher in the NeP group than those in the NocP group, and the postoperative NRS_LBP and NRS_LP score was significantly higher in the NeP group. Thus, controlling preoperative NeP may improve therapeutic efficacy.

Comparison of outcome between percutaneous pedicle screw fixation and the Mini-Open Wiltse Approach with pedicle screw fixation for neurologically intact thoracolumbar fractures: A retrospective study

BACKGROUND

The purpose of this study was to compare the outcome between percutaneous pedicle screw fixation (PPSF) and the mini-open Wiltse approach with pedicle screw fixation (MWPSF) for neurologically intact thoracolumbar fractures.

METHODS

From January 2017 to January 2019, ninety-four patients with neurologically intact thoracolumbar fractures were included in this study. In this retrospective study, forty-nine patients were operated with the PPSF and forty-five patients received MWPSF. The clinical information, surgery-related results and radiographic outcome were collected and compared between the two groups.

RESULTS

There was no significant difference between the two groups in total length of incisions, blood loss, post-operative hospitalization time, visual analog scale (VAS) score and Oswestry disability index (ODI) score. There was also no significant difference in the accuracy rate of pedicle screw placement between two groups; however, the facet joint violation (FJV) was significantly higher in the PPSF group. The atrophic area of multifidus muscle in the PPSF group is significantly larger than that in the MWPSF group and the operative time of MWPSF group was shorter than that in the PPSF group. Meanwhile, the PPSF group obtaining significantly more cumulative exposure to radiation (p < 0.001). The result of vertebral body angle (VBA), Cobb's angle and AVH rate in the MWPSF group were significantly better than those in the PPSF group at the last post-operative follow-up.

CONCLUSIONS

Both minimally invasive treatment techniques (PPSF and MWPSF) are safe and effective in treatment of neurologically intact thoracolumbar fractures. Nevertheless, our results indicate that MWPSF may be a better choice for neurologically intact thoracolumbar fractures, since it protects multifidus muscle, and decreases facet joint violation, operation time, as well as radiation exposure. In addition, MWPSF was associated with better reduction of kyphosis.

Comparative Study of Cage Subsidence in Single-Level Lateral Lumbar Interbody Fusion

We investigated the incidence and clinical features of cage subsidence after single-level lateral lumbar interbody fusion (LLIF). We studied a retrospective cohort of 59 patients (34 males, 25 females; mean age, 68.9 years) who received single-level LLIF. Patients were classified into subsidence and no-subsidence groups. Cage subsidence was defined as any violation of either endplate, classified using radiographs and computed tomography (CT) images. After one year, we compared patient characteristics, surgical parameters, radiological findings, pain scores, and fusion status. We also compared the Hounsfield unit (HU) endplate value obtained on CT preoperatively. Twenty patients (33.9%) had radiographic evidence of interbody cage subsidence. There were significant differences between the subsidence and no-subsidence groups in sex, cage height, fusion rate, and average HU value of both endplates (p < 0.05). There were no significant differences in age, height, weight, or body mass index. Moreover, there were no significant differences in global alignment and Numerical Rating Scale change in low back pain, leg pain, and numbness. Despite suggestions that patients with lower HU values might develop cage subsidence, our results showed that cage subsidence after single-level LLIF was not associated with low back pain, leg pain, or numbness one year post-operation.

Single position lumbar fusion: a systematic review and meta-analysis

BACKGROUND CONTEXT

Recently, a single position lumbar fusion has been described in which both the anterior or lateral interbody fusion as well as posterior percutaneous pedicle screw fixation are performed in a single position.

PURPOSE

The purpose of this study was to present and analyze the current evidence for single position lumbar fusion.

STUDY DESIGN/SETTING

This is a systematic review and meta-analysis.

PATIENT SAMPLE

Prospective or retrospective studies published in English that assessed outcomes of single position lumbar fusion surgery for patients with lumbar degenerative disease, spondylolisthesis, or radiculopathy were included.

OUTCOME MEASURES

Outcome measures included operative time, estimated blood loss, hospital length of stay, X-Ray exposure time, and postoperative outcomes including leg numbness or pain, leg weakness, lumbar lordosis, and segmental lordosis.

METHODS

This systematic review was performed in accordance with PRISMA guidelines. Two separate meta-analyses were performed. The first compared single position (SP) surgery, both lateral and prone, to dual position or flipped (F) surgery. The second meta-analysis compared lateral single position (LSP) surgery to prone single position (PSP) surgery. Variables were included if (1) they were a mean with a reported standard deviation or (2) if they were a categorical variable. For calculating standard error of the mean, we used sample size, mean, and standard deviation. A random effects model was used. The heterogeneity among studies was assessed with a significance level of <0.05.

RESULTS

Twenty-one articles were included for analysis. Three studies were prospective nonrandomized studies, while 18 were retrospective. Seven articles studied lateral single position only, 10 articles compared lateral single position to traditional repositioning surgery, three articles studied prone single position surgery, and one article compared prone single position surgery to traditional repositioning surgery. A detailed review is provided for all 21 articles. Seventeen studies were included for meta-analysis comparing the SP versus F groups, for a total of 942 patients in the SP group and 254 in the F group. Mean operative time was significantly less for the SP group compared with the F group (SP: 127.5±7.9, F: 188.7±15.5, p<.001). Average hospital length of stay was 2.87±0.3 days in the SP group and 6.63±0.6 days in the F group (p<.001). Complication rates did not significantly differ between groups. Pedicle screws placed in the lateral position had a higher rate of complication as compared with those placed in a prone position (L: 10.2±2%, P: 1.6±1%, p=.015). Seventeen studies were included in the LSP versus PSP analysis, including 13 in the LSP group and four in the PSP group, with a total of 785 patients in the LSP group and 85 patients in the PSP group. Operative time and X-Ray exposure was significantly less in the LSP compared with the PSP group (117.1±5.5 minutes vs. 166.9±21.9 minutes, p<.001; 43.7±15.5 minutes vs. 171.0±25.8 minutes, p<.001). Postoperative segmental lordosis was greater in the prone single position group (p<.001).

CONCLUSIONS

Single position surgery decreases operative times and hospital length of stay, while maintaining similar complication rates and radiographic outcomes. PSP surgery was found to be longer in duration and have increased radiation exposure time compared with LSP, while increasing postoperative segmental lordosis.

Effects of preoperative sagittal spinal imbalance on pain after lateral lumbar interbody fusion

Sagittal misalignment has been associated with negative quality of life (QOL). However, there is no report on whether differences in preoperative sagittal misalignment in patients with lumbar degenerative diseases affect postoperative results after lateral lumbar interbody fusion (LLIF). We investigated whether preoperative sagittal alignment influences the correction of alignment after surgery and whether the preoperative sagittal alignment affects the rating of low back pain, leg pain, and leg numbness. The subjects were 81 patients (48 male, 33 females, average age at surgery 70.2 years) who underwent anterior-posterior combined surgery with LLIF and percutaneous pedicle screws from May 2018 to July 2020. Cluster analysis was performed using the preoperative sagittal vertical axis (SVA) value, and patients were classified into two groups (group 1; n = 30, SVA = 129.0 ± 53.4 mm, group 2; n = 51, SVA = 30.8 ± 23.5 mm). Baseline demographics and treatment data were compared between groups. Sagittal and pelvic parameters and pain scores, such as low back pain, leg pain, and leg numbness, were also compared. Operative time, blood loss, and length of hospital stay did not differ significantly between groups. The changes (Δ) in SVA and lumbar lordosis (LL) for all patients from before to after surgery were not significant (ΔSVA; p = 0.218, ΔLL; p = 0.189, respectively). The SVA, LL, and PI - LL changed significantly after the surgery in group 1, but no marked improvement in sagittal imbalance was obtained after LLIF surgery. The improvement in each pain score from before to after the surgery did not differ significantly between groups. LLIF surgery has a limited chance of recovering sagittal imbalance. However, postoperative low back pain, leg pain, and leg numbness may be improved by LLIF surgery, regardless of the preoperative sagittal alignment.

Surgical fixation of pathologic and traumatic spinal fractures using single position surgery technique in lateral decubitus position

STUDY DESIGN

Retrospective Case Series.

OBJECTIVES

This study aims to determine complications, readmission, and revision surgery rates in patients undergoing single position surgery (SPS) for surgical treatment of traumatic and pathologic thoracolumbar fractures.

METHODS

A multi-center review of patients who underwent SPS in the lateral decubitus position (LSPS) for surgical management of traumatic or pathologic thoracolumbar fractures between January 2016 and May 2020 was conducted. Operative time, estimated blood loss (EBL), intraoperative complications, postoperative complications, readmissions, and revision surgeries were collected.

RESULTS

A total of 12 patients with a mean age of 45 years (66.67% male) were included. The majority of patients underwent operative treatment for acute thoracolumbar trauma (66.67%) with a mean injury severity score (ISS) of 16.71. Mean operative time was 175.5 min, mean EBL of 816.67 cc. Five patients experienced a complication, two of which required revision surgery for additional decompression during the initial admission. All ambulatory patients were mobilized on postoperative day 1. The mean hospital length of stay (LOS) was 9.67 days.

CONCLUSION

The results of this case series supports LSPS as a feasible alternative to the traditional combined anterior-posterior approach for surgical treatment of pathologic and thoracolumbar fractures. These results are similar to reductions in operative time, EBL, and LOS seen in the elective spine literature with LSPS.

LEVEL OF EVIDENCE

IV.

Radiographic and clinical evaluation of single-level lateral interbody fusion in patients with severe stenosis analyzed using cluster analysis

This study was a retrospective review of patients treated in a single institution. We performed a cluster analysis of the degree of preoperative stenosis to investigate the effect of indirect neural decompression in single-level lateral lumbar interbody fusion (LLIF). Surgery is generally indicated for patients with severe stenosis. On the other hand, severe lumbar spinal stenosis is a relative contraindication to LLIF and is excluded in most studies. If LLIF, which is less invasive to treatment, can be applied to severe stenosis patients, it may help treatment. Cluster analysis classified 80 patients into 3 groups based on preoperative central canal area (CCA), preoperative canal diameter (CD), and preoperative Schizas grade: group 1 with severe stenosis (n = 43); group 2 with moderate stenosis (n = 27); and group 3 with mild stenosis (n = 10). Preoperative and immediately postoperative CCA and CD in magnetic resonance imaging were compared between groups. Disc angle (DA) and anterior, posterior, and average disc heights (AvDH) (anterior disc height, posterior disc height, average disc height AvDH) were measured using standing lateral plain radiographs. For clinical analysis, a numeric rating scale was used to evaluate clinical outcomes. DA, anterior disc height, posterior disc height, and AvDH increased significantly after the operation in all groups, but the average changes in these factors did not differ. Mean midsagittal CD and axial CCA on MRI magnetic resonance imaging increased significantly in all groups, but as with DA and DH, the changes in axial CCA and midsagittal CD did not differ between groups. The numeric rating scale score did not differ between groups at any time. The cluster analysis results suggested that postoperative changes in indirect neural decompression for severe stenosis after LLIF similar for moderate and mild stenosis and that pain did not differ according to the severity of stenosis after surgery.

Supine lateral lumbar interbody fusion: cadaveric proof of principle for simultaneous anterior and lateral approaches

BACKGROUND

Anterior lumbar interbody fusion (ALIF) and lateral lumbar interbody fusion (LLIF) are commonly performed in separate stages with a change in patient positioning to provide arthrodesis in the lumbar spine. Interest has recently emerged in performing these approaches as a single-stage surgery with the patient in the lateral decubitus position. The objective of this study was to evaluate the technical feasibility of performing minimally invasive anterolateral fixation in a single supine position.

METHODS

Two fresh-frozen cadavers were used and placed supine. Standard minimally invasive anterior access was obtained by the approach surgeon. An ALIF was performed at L5-S1 using standard techniques. A lateral incision was marked over the L4-5 disc space using fluoroscopy. Direct palpation and bimanual dissection were achieved through the same anterior incision, allowing access to the retroperitoneal space. Dilator and retractor docking was performed under fluoroscopic guidance. Direct visualization of the docking hardware through the anterior incision was used to ensure the safety of peritoneal contents and vasculature. The LLIF was then performed using standard techniques at L4-5.

RESULTS

Plain radiographs confirmed acceptable positioning of both the ALIF and LLIF grafts. No injury to the cadaveric peritoneum, vasculature, or lumbar plexus was observed. A slightly enlarged anterior incision also permitted retroperitoneal access and visualization of the L3-4 disc space.

CONCLUSION

This cadaver feasibility study demonstrates that combined minimally invasive ALIF and LLIF procedures may be performed as a single-stage with the patient in the supine position. Clinical consideration and study of this approach are warranted.

Intraoperative computed tomography-guided navigation versus fluoroscopy for single-position surgery after lateral lumbar interbody fusion

There are no reports comparing fluoroscopy and intraoperative computed tomography (CT) navigation in lateral single-position surgery (SPS) in terms of surgical outcomes or implant-related complications. Therefore, the purpose of this study was to use radiological evaluation to compare the incidence of instrument-related complications in SPS of lateral lumbar interbody fusion (LLIF) using fluoroscopy with that using CT navigation techniques. We evaluated 99 patients who underwent lateral SPS. Twenty-six patients had a percutaneous pedicle screw (PPS) inserted under fluoroscopy (SPS-C group), and 73 patients had a PPS inserted under intraoperative CT navigation (SPS-O group). Average operation time was shorter in the SPS-C group than in the SPS-O group (88.4 ± 24.4 min versus 111.9 ± 35.3 min, respectively, P = 0.003). However, there was no significant difference between the two groups in postoperative thigh symptoms or reoperation rate. The screw insertion angle of the SPS-C group was smaller than that of the SPS-O group, but there was no significant difference in the rate of screw misplacement (4.6% versus 3.4%, respectively, P = 0.556). By contrast, facet joint violation (FJV) was significantly lower in the SPS-O group than in the SPS-C group (8.4% versus 21.3%, respectively, P < 0.001). While fluoroscopy was superior to intraoperative CT navigation in terms of mean surgery time, there was no significant difference in the accuracy of PPS insertion between fluoroscopy and intraoperative CT navigation. The advantage of intraoperative CT navigation over fluoroscopy is that it significantly decreases the occurrence of FJV in SPS.

Utility of Power Tool and Intraoperative Neuromonitoring for Percutaneous Pedicle Screw Placement in Single Position Surgery: A Technical Note

OBJECTIVE

This study aimed to demonstrate the utility of power tools and intraoperative neuromonitoring of percutaneous pedicle screw (PPS) insertion (so-called PPS monitoring) by SINGLE-position surgery (SPS) after lateral lumbar interbody fusion.

METHODS

A retrospective analysis of medical records from a single center was performed to identify patients who underwent SPS for lateral lumbar interbody fusion and posterior fixation using PPS during intraoperative computed tomography navigation from 2020 to 2021. We investigated the PPS insertion time and screw positional accuracy of patients who underwent SPS involving power tools and PPS monitoring during this period. In this technical note, we report on this surgical technique.

RESULTS

Twenty-four patients (mean age 72.0 ± 8.5 years, range 53-81 years) were included in this study. There were no intraoperative complications in all cases. Posterior fixation using PPS was added in all cases, and a total of 106 PPSs were inserted. It took an average of 6.2 ± 2.4 seconds to insert the PPS from the PPS insertion point to the end using a power tool and PPS monitoring. Moreover, there were no cases of pedicle breaches.

CONCLUSIONS

Similar to previous reports related to power tools in the prone position, the lateral decubitus SPS technique can also use power tools to save PPS insertion time. Furthermore, we suggest that the use of PPS monitoring may prevent erroneous PPS insertions by using intraoperative computed tomography navigation in advance.

Minimally Invasive L5 Corpectomy with Navigated Expandable Vertebral Cage: A Technical Note

Background: Conventional L5 corpectomy requires a large incision and an extended period of intraoperative fluoroscopy. We describe herein a new L5 corpectomy technique. Methods: A 79-year-old woman was referred to our hospital for leg pain and lower back pain due to an L5 vertebral fracture. Her daily life had been affected by severe lower back pain and sciatica for more than 2 months. We initially performed simple decompression surgery, but this proved effective for only 10 months. Results: For revision surgery, the patient underwent minimally invasive L5 corpectomy with a navigated expandable cage without fluoroscopy. The second surgery took 215 min, and estimated blood loss was 750 mL. The revision surgery proved successful, and the patient could then walk using a cane. In terms of clinical outcomes, the Oswestry Disability Index improved from 66% to 24%, and the visual analog scale score for lower back pain improved from 84 to 31 mm at the 1-year follow-up. Conclusions: Minimally invasive L5 corpectomy with a navigated expandable vertebral cage is effective for reducing cage misplacement and surgical invasiveness. With this new technique, surgeons and operating room staff can avoid the risk of adverse events due to intraoperative radiation exposure.

Prone transpsoas lumbar corpectomy: simultaneous posterior and lateral lumbar access for difficult clinical scenarios

OBJECTIVE

Lateral lumbar corpectomy with interbody fusion has been well described via a transpsoas approach in the lateral position, as has lumbar interbody fusion with posterior fixation in the prone position. However, no previous report has described the use of both an open posterior approach and a lateral transpsoas approach simultaneously in the prone position. Here, the authors describe their technique of performing transpsoas lumbar corpectomy in the prone position in order to have simultaneous posterior and lateral access for difficult clinical scenarios, and they report their early clinical experience.

METHODS

The surgical technique for simultaneous posterior and lateral transpsoas access to the lumbar spine was reviewed and described in detail. The cases of 2 patients who underwent simultaneous posterior and lateral access in the prone position for complex lumbar pathology were retrospectively reviewed. Clinical presentation, preoperative radiographs, postoperative course, and postoperative radiographs were reviewed.

RESULTS

The first patient presented after previous transforaminal lumbar interbody fusion that was complicated by significant subsidence of the intervertebral cage, vertebral body split fracture, rotational instability, and resulting spinal stenosis. A simultaneous posterior and lateral transpsoas approach in the prone position allowed for removal of the previous cage, lumbar corpectomy, and rigid posterior fixation with direct decompression. The second patient had a significant pathologic burst fracture secondary to a plasmacytoma with retropulsion, resulting in vertebra plana and significant canal stenosis. Simultaneous approaches allowed for complete resection of the plasmacytoma, restoration of lumbar alignment, rigid fixation, and direct posterior decompression. There were no short-term complications, and both patients had resolution of their preoperative symptoms.

CONCLUSIONS

Simultaneous posterior and lateral transpsoas access to the lumbar spine in the prone position is a previously unreported technique that allows a safe surgical approach to difficult clinical scenarios.

Simultaneous Robotic Single Position Oblique Lumbar Interbody Fusion With Bilateral Sacropelvic Fixation in Lateral Decubitus

Single position lateral fusion reduces the need for a secondary surgery and robotic guidance allows for potentially higher accuracy of screw placement. We expand the role of robotics with a simultaneous workflow where 2 surgeons can work in single position surgery and discuss the technical feasibility of placement of S2-alar-iliac (S2AI) screws in the lateral position. A 70-year-old male presented with chronic back pain and bilateral leg pain with the left side worse than the right. He subsequently underwent an L3–S1 oblique lumbar interbody fusion (OLIF) with a minimally invasive L3-ilium robotic posterior spinal fixation simultaneously in single lateral position with S2AI screws. The software planning requisite of robotics allowed for a preoperative plan where lumbar cortical screws were used to line up with bilateral S2AI screws. Intraoperatively, the OLIF was performed anterior to the patient which allowed for a second surgeon to perform the posterior stage of screw placement simultaneously in overlapping fashion during OLIF exposure. Once all screws were placed, the OLIF discectomy and cage placement were completed. As the OLIF incision is closed, rodding proceeds posteriorly with subsequent closure simultaneously as well. Operative time from skin incision to skin closure was 3 hours and 47 minutes. We present here a novel technical report on the recommended workflow of simultaneous robotic single position surgery OLIF and demonstrate the feasibility of placement of sacroiliac fixation in the lateral decubitus position. We believe this technique to be minimally invasive, effective, with the benefit of shortening valuable operating room case time.

Radiographs assessment of changes in the psoas muscle at L4-L5 level after single-level lateral lumbar interbody fusion in patients with postoperative motor weakness

The purposes of this study were (1) to investigate postoperative changes in cross-sectional area (CSA) and signal intensity (SI) of the psoas muscle (PS) using magnetic resonance imaging (MRI) and (2) to compare the CSA and SI of the PS between patients with and without motor weakness after single-level lateral lumbar interbody fusion (LLIF) at level L4-L5. Sixty patients were divided into two groups-those with postoperative motor weakness and those without-and the two groups were compared. Baseline demographics and clinical characteristics, such as operation time and blood loss, length of hospital stay, and postoperative complications, were recorded. The CSA and SI of the PS were obtained from the MRI regions of interest defined by manual tracing. Patients who developed motor weakness after surgery were significantly older (p = 0.040). The operation time (p = 0.868), LLIF operative time (p = 0.476), and estimated bleeding loss (p = 0.168) did not differ significantly between groups. In both groups, the CSA and SI of the left and right PS increased after surgery. The change in the CSA of the left PS was significantly higher in patients with weakness (247.6 ± 155.2 mm²) than without weakness (152.2 ± 133.1 mm²) (p = 0.036). The change in SI of the left PS did not differ between the two groups (p = 0.530). To prevent postoperative motor weakness regardless of the operation time, surgeons should be aware of the potential for surgical invasive of the PS during LLIF in older people.

Posterior spinal fixation using penetrating endplate screws in patients with diffuse idiopathic skeletal hyperostosis-related thoracolumbar fractures

OBJECTIVE

Diffuse idiopathic skeletal hyperostosis (DISH)-related vertebral fractures essentially require operative treatment due to severe fracture site instability and high potential risk of posttraumatic neurological deficit. However, the optimal surgical procedure remains unclear. The purpose of this study was to assess the efficacy of posterior spinal fixation with penetrating endplate screws (PESs) for DISH-related thoracolumbar fractures.

METHODS

The authors conducted a retrospective, single-center, observational study. They included data from 26 consecutive patients with DISH-related thoracolumbar fractures who were treated with posterior spinal fixation using either conventional pedicle screws (PS group, n = 8) or a combined PES technique (PES group, n = 18) between 2013 and 2019. Age, sex, BMI, bone mineral density, fracture level, use of antithrombotic drug, blood loss, operation time, fixation range, perioperative American Spinal Injury Association Impairment Scale score, implant failure, revision surgery, complications, and mortality were compared. The authors also evaluated screw loosening and bone healing on radiographs and CT scans.

RESULTS

More patients had vertebral fractures in the lumbar spine in the PS group than in the PES group (3 vs 0; p = 0.019). Patients in the PES group had less blood loss (63 vs 173 ml; p = 0.048) and shorter range of fixation (5 vs 5.5 levels; p = 0.041). The screw loosening rate was significantly lower in the PES group than in the PS group (3% vs 49%; p < 0.001).

CONCLUSIONS

Posterior spinal fixation using a PES technique may be an ideal surgical procedure for thoracolumbar fractures with DISH, providing more rigid and less invasive fixation than PS.

Simultaneous Robotic Single-Position Surgery (SR-SPS) with Oblique Lumbar Interbody Fusion: A Case Series

BACKGROUND

The oblique lateral interbody fusion (OLIF) procedure is an important component of the surgeon's armamentarium for the treatment of degenerative spinal conditions. OLIF with posterior spinal fixation frequently is performed and requires additional time because the patient is flipped to a prone position and redraped. We report a series of cases in which robotic-assistance was used for a 2-surgeon workflow in which OLIF and single lateral position posterior spinal fixation were performed at the same time, termed simultaneous robotic single position surgery (SR-SPS).

METHODS

Data were collected retrospectively from medical records of 13 consecutive patients who underwent SR-SPS by a single surgeon at an academic center between June and December 2020. Instrumentation accuracy, total operating room time, estimated blood loss, length of stay, and complications were assessed.

RESULTS

A total of 13 patients whose mean age was 64.1 years (range 46-84 years) underwent SR-SPS over a 6-month period. Average follow-up was 10.3 months. All patients were treated for degenerative spine disease. The average operative duration was 111.2 ± 25.2 minutes. A total of 60 pedicle screws were placed bilaterally in the lateral position with an accuracy rate of 95.0%. Complications included 1 postoperative seroma, and 1 patient required reoperation 3 months postoperatively due to a fall.

CONCLUSIONS

We report the first case series describing SR-SPS. Our study shows that this method can reduce operative time while ensuring accurate and timely screw placement with minimal complications.

Safety and Efficacy of All-In-One Percutaneous Pedicle Screw System

STUDY DESIGN

Retrospective study of the prospectively collected outcomes data.

OBJECTIVE

The indications for PPS placement during minimally invasive spine stabilization (MISt) procedures have increased in recent years. To the best of our knowledge, no studies have documented the outcomes of PPS insertion using the all-in-one PPS system. This study compared the conventional methods and the use of all-in-one percutaneous pedicle screw (PPS) system with respect to the speed and accuracy of PPS placement. We also determined the advantages associated with the use of the all-in-one PPS system.

METHODS

We evaluated 54 patients who underwent PPS insertion using the conventional method and the all-in-one PPS system during MISt procedures. We also assessed the number of implanted PPSs, the time taken to implant PPSs, and the accuracy of PPS placement based on postoperative computed tomography images.

RESULTS

A total of 254 PPSs were inserted (126 using the conventional method and 128 using the all-in-one PPS system). The PPS insertion time with the all-in-one PPS system (mean, 25.3 ± 9.1 s) was significantly shorter than that using the conventional method (mean, 63.1 ± 13.0 s; P < 0.01). With respect to the accuracy of PPS insertion, ≥ 2 mm pedicle breach was noted in one case each in both groups.

CONCLUSIONS

PPS placement using the all-in-one PPS system is as safe as conventional methods and has the potential to save the surgical time of MISt procedures.

Accuracy of Percutaneous Pedicle Screw Placement after Single-Position versus Dual-Position Insertion for Lateral Interbody Fusion and Pedicle Screw Fixation Using Fluoroscopy

Study Design

Retrospective study.

Purpose

The purpose of this study was to compare the accuracy of percutaneous pedicle screw (PPS) placement between prone and lateral decubitus positions during lateral lumbar interbody fusion (LLIF) and to evaluate the tendency of PPS positioning based on simple computed tomography measurements with patients in the lateral decubitus position.

Overview of Literature

There is insufficient information in the literature regarding the accuracy of inserting a PPS using fluoroscopy in patients in the lateral decubitus position.

Methods

We included 62 patients who underwent combined LLIF surgery and PPS fixation for degenerative lumbar spondylolisthesis with spinal canal stenosis. We compared the patient demographics and the accuracy of fluoroscopy-guided PPS placement between two groups: patients who remained in the lateral decubitus position for the pedicle screw fixation (single-position surgery [SPS] group) and those who were turned to the prone position (dual-position surgery [DPS] group).

Results

There were 40 patients in the DPS group and 22 in the SPS group. Of the 292 PPSs, only 12 were misplaced. In other words, 280/292 screws (95.9%) were placed correctly in the pedicle's cortical shell (grade 0). PPS insertion did not cause neurological, vascular, or visceral injuries in either group. The breach rates for the DPS and SPS groups were 4.1% (grade 1, 5 screws; grade 2, 3 screws; grade 3, 0 screw) and 4.1% (grade 1, 2 screws; grade 2, 2 screws; grade 3, 0 screw), respectively. Although there were no statistically significant differences, the downside PPS had more screw malpositioning than the upside PPS.

Conclusions

We found that PPS insertion with the patient in the decubitus position under fluoroscopic guidance might be as safe and reliable a technique as PPS insertion in the prone position, with a misplacement rate similar to that previously published.

Single-Position Surgery versus Lateral-Then-Prone-Position Circumferential Lumbar Interbody Fusion: A Systematic Literature Review

OBJECTIVE

We sought to compare the outcomes of single-position (SP) circumferential lumbar interbody fusion in lateral decubitus versus dual-position (DP) fusion.

METHODS

A systematic literature review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines in PubMed, Web of Science, and Scopus databases to identify comparative studies reporting the outcomes of SP lumbar interbody fusion versus DP. For risk of bias assessment, the ROBINS-I (risk of bias in nonrandomized studies of interventions) tool was used.

RESULTS

Four comparative studies were included from an initial search of 3780 papers. All 4 studies were retrospective cohort studies comparing outcomes of SP versus DP LLIF. A total of 349 patients were operated using SP versus 254 using DP. All studies involved reported operating time, estimated blood loss, length of stay, change in segmental lordosis, and complications. From a general perspective, baseline variables were similar in both groups in all the studies and all reported a significant decrease in operative time and length of stays with SP.

CONCLUSIONS

Literature comparing SP versus lateral-then-prone lumbar fusion shows a tendency toward shorter operating time and hospital stays in SP lumbar fusion while maintaining similar perioperative outcomes.

Safety Profile, Surgical Technique, and Early Clinical Results for Simultaneous Lateral Lumbar Interbody Fusion and Anterior Lumbar Interbody Fusion in a Lateral Position

STUDY DESIGN

Description of surgical technique and retrospective review.

OBJECTIVE

To describe a novel surgical technique for multilevel lumbar fusion and describe early clinical results.

SUMMARY OF BACKGROUND DATA

Patients with multilevel lumbar spinal stenosis and adult degenerative scoliosis often require multilevel interbody placement to achieve indirect decompression and lordosis. We describe a case series of patients treated with simultaneous lateral lumbar interbody fusion (LLIF) and anterior lumbar interbody fusion (ALIF) at L5-S1.

METHODS

We retrospectively reviewed a consecutive series of patients treated for multilevel lumbar spinal stenosis with simultaneous ALIF and LLIF with at least 3-month follow-up. All patients received supplemental percutaneous bilateral pedicle screw placement as well. We measured on preoperative radiographs their lumbar lordosis, pelvic incidence, and L5-S1 lordosis. Intraoperative factors such as operative time, estimated blood loss, fluids provided, number of levels fused, and whether a trainee was present during the procedure were all recorded.

RESULTS

There were 15 patients included within our case series (69.5, 4 F). There were no reported intraoperative vascular or neurological complications in 15 cases. The operative time for the cases ranged from 2.7 to 8.4 hours (average=5.2±1.9 h). The average lordosis gained at L5-S1 was 8.6±3.0 degrees and the average lumbar lordosis gained was 14.7±6.4 degrees. The average PI-LL mismatch went from 22.4±13.3 degrees preoperative to 7.8±10.2 degrees postoperative. One patient had a postoperative complication of a sacral fracture requiring placement of a pelvic screw for a L2-pelvis fusion. There were 8 patients with 4+ levels of fusion. For this cohort of patients, the average lumbar lordosis gained was 16.0±7.5 degrees and the average PI-LL mismatch went from 24.7±16.3 degrees preoperative to 8.8±12.9 degrees postoperative. For the patients with 4+ levels of fusion, the average operative time was 5.9±1.8 hours.

CONCLUSIONS

We have described our early positive results with simultaneous LLIF/ALIF surgery for treatment of lumbar degenerative conditions.

Lateral lumbar interbody fusion after reduction using the percutaneous pedicle screw system in the lateral position for Meyerding grade II spondylolisthesis: a preliminary report of a new lumbar reconstruction strategy

BACKGROUND

Utilization of a cage with a large footprint in lateral lumbar interbody fusion (LLIF) for the treatment of spondylolisthesis leads to a high fusion rate and neurological improvement owing to the indirect decompression effect and excellent alignment correction. However, if an interbody space is too narrow for insertion of an LLIF cage for cases of spondylolisthesis of Meyerding grade II or higher, LLIF cannot be used. Therefore, we developed a novel strategy, LLIF after reduction by the percutaneous pedicle screw (PPS) insertion system in the lateral position (LIFARL), for surgeons to perform accurate and safe LLIF with PPS in patients with such pathology. This study aimed to introduce the new surgical strategy and to present preliminary clinical and radiological results of patients with spondylolisthesis of Meyerding grade II.

METHODS

Six consecutive patients (four men and two women; mean age, 72.7 years-old; mean follow-up period, 15.3 months) with L4 spondylolisthesis of Meyerding grade II were included. Regarding the surgical procedure, first, PPSs were inserted into the L4 and L5 vertebrae fluoroscopically, and both rods were placed in the lateral position. The L5 set screws were fixed tightly, and the L4 side of the rod was floated. Second, the L4 vertebra was reduced by fastening the L4 set screws so that they expanded the anteroposterior width of the interbody space. At that time, the L4 set screws were not fully tightened to the rods to prevent the endplate injury. Finally, the LLIF procedure was started. After inserting the cage, a compression force was added to the PPSs, and the L4 set screws were completely fastened.

RESULTS

The mean operative time was 183 min, and the mean blood loss was 90.8 mL. All cages were positioned properly. Visual analog scale score and Oswestry disability index improved postoperatively. Bone union was observed using computed tomography 12 months after surgery.

CONCLUSION

For cases with difficulty in LLIF cage insertion for Meyerding grade II spondylolisthesis due to the narrow anteroposterior width of interbody space, LIFARL is an option to achieve LLIF combined with posterior PPS accurately and safely.

TRIAL REGISTRATION

UMIN-Clinical Trials Registry, UMIN000040268, Registered 29 April 2020, https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000045938.

Intraoperative image guidance for lateral position surgery

Recent advances in minimally invasive spine surgery techniques have precipitated the popularity of lateral position spine surgery, such as lateral lumbar interbody fusion (LLIF) and oblique lumbar interbody fusion (OLIF). Lateral position surgery offers a unique, minimally invasive approach to the lumbar spine that allows for preservation of anterior and posterior spinal elements. Traditionally, surgeons have relied upon fluoroscopy for triangulation and implant placement. Over the last decade, intraoperative 3-dimensional navigation (ION) has risen to the forefront of innovation in LLIF and OLIF. This technology utilizes intra-operative advanced imaging, such as comminuted tomography (CT), to map the patient’s 3D anatomy and allows the surgeon to accurately visualize instruments and implants in spatial relationship to the patient’s anatomy in real time. ION has the potential to improve accuracy during instrumentation, decrease operating room times, lower radiation exposure to the surgeon and staff, and increase feasibility of single-position surgery during which the spine is instrumented both laterally and posteriorly while the patient remains in the lateral decubitus position. Despite the advantages of ION, the intra-operative radiation exposure risk to patients is controversial. Future directions include continued innovation in ultra low radiation imaging (ULRI) techniques and image enhancement technology and in uses of robot-assisted navigation in single-position spine surgery.

A New Technique that Combines Navigation-Assisted Lateral Interbody Fusion and Percutaneous Placement of Pedicle Screws in the Lateral Decubitus Position with the Surgeon Using Wearable Smart Glasses: A Small Case Series and Technical Note

BACKGROUND

We describe a new technique that combines navigation-assisted extreme lateral interbody fusion (NALIF) and percutaneous placement of pedicle screws in the lateral decubitus position with the surgeon using wearable smart glasses.

METHODS

We explain our method for nonfluoroscopic NALIF and single-position (SP)- percutaneous pedicle screw (PPS) surgery for patients with degenerative lumbar diseases using wearable smart glasses. The wearable smart glasses provide a semitransparent overlay of the navigation information onto the image seen through the lenses. This technique does not require fluoroscopy during lateral interbody fusion or PPS insertion. It is convenient because it does not require a Jamshidi needle or guidewire when inserting PPSs.

RESULTS

Using this method, the surgeon can glance at the 3-dimensional images on the wearable smart glasses while still viewing the operation field. A review of 24 cases yielded an average operation time of 89.5 ± 16.4 minutes and 66.7 ± 67.0 mL of blood loss, without any severe intra- or postoperative complications.

CONCLUSIONS

Nonfluoroscopic NALIF and SP-PPS placement surgery is a safe and effective means for implanting cages and PPSs in this minimally invasive approach without compromising the results. Although further investigations are needed, the wearable smart glasses may be a useful surgical aid when performing NALIF and SP-PPS placement in patients with degenerative lumbar diseases.

Single-position prone lateral approach: cadaveric feasibility study and early clinical experience

OBJECTIVE

Lateral lumbar interbody fusion (LLIF) is a useful minimally invasive technique for achieving anterior interbody fusion and preserving or restoring lumbar lordosis. However, achieving circumferential fusion via posterior instrumentation after an LLIF can be challenging, requiring either repositioning the patient or placing pedicle screws in the lateral position. Here, the authors explore an alternative single-position approach: LLIF in the prone lateral (PL) position.

METHODS

A cadaveric feasibility study was performed using 2 human cadaveric specimens. A retrospective 2-center early clinical series was performed for patients who had undergone a minimally invasive lateral procedure in the prone position between August 2019 and March 2020. Case duration, retractor time, electrophysiological thresholds, implant size, screw accuracy, and complications were recorded. Early postoperative radiographic outcomes were reported.

RESULTS

A PL LLIF was successfully performed in 2 cadavers without causing injury to a vessel or the bowel. No intraoperative subsidence was observed. In the clinical series, 12 patients underwent attempted PL surgery, although 1 case was converted to standard lateral positioning. Thus, 11 patients successfully underwent PL LLIF (89%) across 14 levels: L2–3 (2 of 14 [14%]), L3–4 (6 of 14 [43%]), and L4–5 (6 of 14 [43%]). For the 11 PL patients, the mean (± SD) age was 61 ± 16 years, mean BMI was 25.8 ± 4.8, and mean retractor time per level was 15 ± 6 minutes with the longest retractor time at L2–3 and the shortest at L4–5. No intraoperative subsidence was noted on routine postoperative imaging.

CONCLUSIONS

Performing single-position lateral transpsoas interbody fusion with the patient prone is anatomically feasible, and in an early clinical experience, it appeared safe and reproducible. Prone positioning for a lateral approach presents an exciting opportunity for streamlining surgical access to the lumbar spine and facilitating more efficient surgical solutions with potential clinical and economic advantages.