Prone vs. lateral positioning for lateral lumbar interbody fusion: a narrative review of clinical outcomes and complications

Introduction

Background

Lateral lumbar interbody fusion (LLIF) is a widely utilized minimally invasive surgical approach for the treatment of degenerative lumbar spine conditions (1-5). By accessing the intervertebral disc space through a lateral retroperitoneal corridor, LLIF facilitates indirect decompression, segmental fusion, and correction of coronal and sagittal alignment while minimizing soft tissue disruption and blood loss compared with traditional anterior or posterior approaches (1,4,6-9).

Rationale

The lateral decubitus position, formally described by Ozgur et al., has long been the standard approach for LLIF and has demonstrated favorable clinical and radiographic outcomes across a broad range of pathologies (1). In this position, table flexion increases the working corridor between the iliac crest and costal margin, which is particularly advantageous for accessing lower lumbar levels (1,4,10,11). Traditionally, lateral decubitus LLIF (ldLLIF) required subsequent repositioning to prone for posterior decompression or instrumentation, resulting in a dual-position workflow (7,12-14).

More recently, prone LLIF (pLLIF) has gained attention as a single-position strategy that permits interbody placement and posterior procedures without intraoperative repositioning (3,8,15,16). Early reports have associated pLLIF with improved operative efficiency and increased lumbar lordosis, effects that are influenced by both prone positioning and workflow consolidation (16-19). Prone positioning may also result in posterior migration of the psoas muscle and lumbar plexus, potentially altering the available transpsoas working corridor (7,20-22). At the same time, contemporary techniques increasingly allow LLIF to be performed in a single-position lateral decubitus workflow, challenging the assumption that prone positioning alone accounts for observed efficiency or alignment advantages (19,23-25).

Although both pLLIF and ldLLIF, whether dual-position or single-position, have demonstrated favorable clinical and radiographic outcomes, each approach introduces distinct anatomical, ergonomic, neurologic, and workflow-related considerations (3,5,8,11,16,17,19,22,26). As a result, reported differences between techniques may reflect not only patient positioning but also differences in operative sequencing, posterior surgical extent, and surgeon experience (16,18,27).

Objective

The objective of this narrative review is to compare pLLIF and ldLLIF using contemporary literature that includes single-arm series as well as direct comparative studies, the latter evaluating pLLIF relative to both dual-position and single-position lateral decubitus workflows (16-19,25). By synthesizing evidence on surgical technique, operative workflow, clinical and radiographic outcomes, and complication profiles, this review provides an up-to-date comparative perspective on the relative contributions of positioning and workflow to observed differences in efficiency and clinical outcomes, offering a practical, evidence-based framework to guide positioning decisions in lateral lumbar fusion surgery (13,14,25). We present this article in accordance with the Narrative Review reporting checklist (available at https://asj.amegroups.com/article/view/10.21037/asj-25-69/rc).

Methods

A literature search was conducted to compare pLLIF and ldLLIF (Table 1). Searches were performed in PubMed, Scopus, Web of Science, and Google Scholar using a combination of Medical Subject Headings and free-text terms, including “lateral lumbar interbody fusion”, “LLIF”, “prone lateral lumbar interbody fusion”, “prone LLIF”, “lateral decubitus lateral lumbar interbody fusion”, and “lateral decubitus LLIF”, in combination with “clinical outcomes” and “complications”. The search timeframe was January 1, 2000 through March 31, 2025. No language restrictions were applied, although priority was given to studies published in English.

Eligible studies included randomized controlled trials, cohort studies, case series, systematic reviews, and meta-analyses that reported radiographic outcomes, patient-reported outcomes, or complication rates related to prone or lateral decubitus positioning for LLIF. Exclusion criteria included case reports, non-human studies, conference abstracts without full text, and articles not directly related to LLIF positioning.

Four independent reviewers conducted the initial screening of titles and abstracts, with full-text review performed by all authors. Disagreements were resolved by consensus with senior authors. To ensure completeness, backward citation tracking was employed to identify additional relevant articles. This review was conducted as a narrative synthesis rather than a formal systematic review, and the search strategy was designed to provide a comprehensive and contemporary overview of the ldLLIF and pLLIF literature within the defined timeframe. While ldLLIF has a longer historical record, much of the literature evaluating contemporary single-position lateral decubitus workflows and all literature on pLLIF is recent, with individual studies frequently reporting multiple aspects of these techniques concurrently. As a result, several foundational studies necessarily inform multiple domains of comparison throughout this review.

Discussion

Technique overview of ldLLIF vs. pLLIF

The approach for ldLLIF involves positioning the patient in a lateral decubitus position on a radiolucent operating table (Figure 1), most commonly right side down to minimize the risk of inferior vena cava injury (1,2,28). However, the choice of laterality may be influenced by patient-specific factors such as prior abdominal surgery, spinal deformity, or retroperitoneal anatomy (1,10,12). Intraoperative neuromonitoring (IONM) leads are typically placed prior to positioning and are used to assess proximity to the lumbar plexus during transpsoas dissection (1,10,12). Once positioned with all bony prominences well-padded, the operating table may be flexed at the level of the iliac crest to increase the working corridor between the rib cage and pelvis, though table break is dependent on surgeon preference, patient anatomy, and the target level (1,4,10).

Figure 1 Schematic illustration of lateral decubitus positioning for lateral lumbar interbody fusion and pedicle screw placement.

Intraoperative fluoroscopy is used to obtain orthogonal views of the target disc level (1,4,10,24). A lateral skin incision centered over the intervertebral disc is made, followed by blunt dissection through the abdominal wall musculature to the transversalis fascia and entry into the retroperitoneal space (1,4,10,28). The peritoneal contents are mobilized anteriorly, exposing the psoas muscle (1,4,10). An initial dilator is docked on the psoas under fluoroscopic guidance, and neuromonitoring is used to navigate a transpsoas corridor while avoiding the lumbar plexus (1,4,10). After sequential dilation, a lateral retractor is placed, followed by standard discectomy, endplate preparation, and interbody cage insertion (1,4,10). Care is taken to maintain orthogonal cage placement relative to the vertebral endplates (1,4,10). After cage placement, the retractor is removed and the incision closed (1,4,10).

Depending on surgical goals, posterior decompression and/or instrumentation may be performed either in the lateral position as part of a single-position ldLLIF workflow or after repositioning the patient prone in a dual-position ldLLIF workflow (12,13,24,29). When pedicle screws are placed in the lateral position, the patient is positioned near the table edge at the start of the case to accommodate a lateral-to-medial screw trajectory (12,23,24). Percutaneous pedicle screws may be placed using fluoroscopic guidance or image-based navigation, with or without robotic assistance (24,29-31). When posterior instrumentation is planned in the prone position, the patient is undraped and repositioned on a Jackson table, after which open or percutaneous posterior decompression and instrumentation may be performed (1,4,12,28).

In the pLLIF approach, the patient is positioned prone on a radiolucent Jackson table with specialized padding that allows the abdomen to hang freely (Figure 2), facilitating lumbar extension and sagittal alignment (3,8,15,17,26). Hip extension, often achieved with padding beneath the knees or thighs, further accentuates lumbar lordosis (11,17,20,26,32,33). The surgical field is prepared to allow access to both the lateral flank and posterior spine, enabling completion of the interbody and posterior procedures without repositioning (3,5,8,15-17,19).

Figure 2 Schematic illustration of prone positioning for lateral lumbar interbody fusion and pedicle screw placement.

Fluoroscopy is used for level localization, followed by a transverse or oblique flank incision (1,3,8-10,15,17,26). Blunt dissection proceeds through the abdominal wall to the transversalis fascia and into the retroperitoneal space (1,3,8,10,15,17,26-28,34). Gravity may contribute to ventral displacement of the peritoneal contents, though the degree of shift is variable and patient dependent (8,15,22,26,28,35). After palpation of the psoas muscle, a central dilator is docked at the mid-disc under fluoroscopic guidance (1,3,8,10,15,17,26,27). IONM is used during transpsoas advancement, ideally following a trajectory through the anterior two-thirds of the muscle (1,3,8,10,15,17,26-28,36). Sequential dilation and retractor placement are followed by standard LLIF steps including annulotomy, discectomy, endplate preparation, and cage insertion (1,3,8,10,15,17,26,27). Posterior decompression and/or instrumentation can then be completed without repositioning (3,5,8,15-17,19,23,26).

Overall, ldLLIF and pLLIF share the same fundamental interbody principles but differ in patient positioning and operative workflow (22,29,37). Importantly, both lateral decubitus and prone approaches can be performed using either single-position or dual-position strategies, and differences in efficiency and ergonomics are often driven by workflow selection rather than positioning alone (3,12-14,19,23,29,38). These distinctions influence how each technique is incorporated into clinical practice (14,23,39-43).

Clinical outcomes and complications of ldLLIF and pLLIF

Both ldLLIF and pLLIF are associated with substantial improvements in pain, function, and radiographic parameters, with overall favorable safety profiles. Interpretation of comparative outcomes, however, requires careful consideration of heterogeneity within the ldLLIF literature itself. Earlier ldLLIF studies predominantly employed dual-position workflows, with lateral interbody placement followed by patient repositioning for posterior instrumentation, whereas more contemporary ldLLIF cohorts increasingly utilize single-position lateral techniques (1,6,23,28,44). In contrast, pLLIF has largely been developed and evaluated as a single-position prone workflow from its inception, integrating interbody placement and posterior instrumentation without repositioning (3,17). Accordingly, Tables 2-4 summarize outcomes stratified by ldLLIF, pLLIF, and direct comparative studies to contextualize reported differences.

ldLLIF outcomes

Clinical and radiographic outcomes following ldLLIF have been extensively reported, with consistent evidence supporting its effectiveness as an indirect decompression strategy across a range of degenerative lumbar pathologies (Table 2). Early work by Bergey et al. and Pimenta et al. established the technique and clinical profile of dual-position ldLLIF, demonstrating durable symptom relief with a mean visual analog scale (VAS) reduction of 5.9 points and 80% of patients reporting excellent or good outcomes at long-term follow-up (28,51). Radiographic fusion was observed in 14 of 15 evaluated patients, and although approach-related groin or thigh paresthesias (30%), and pain (27%) were common, most neurologic symptoms were transient, with no persistent motor deficits, supporting early safety of the transpsoas corridor in a staged workflow (28).

Subsequent larger retrospective cohorts refined understanding of neurologic risk associated with ldLLIF, particularly in dual-position series. Le et al. reported immediate postoperative ipsilateral thigh numbness in 19.7% of patients and iliopsoas or quadriceps weakness in 54.9%, reflecting the proximity of the lumbar plexus during transpsoas access originally described in early anatomic and technical work (27,51). Importantly, motor weakness resolved in 92% of patients by three months and in 100% by 2 years, while sensory deficits improved more gradually, with 64% resolving by 12 months. A clear learning curve effect was demonstrated, with postoperative sensory symptom rates decreasing from 26.1% to 10.7% over time, highlighting the influence of surgeon experience rather than patient positioning alone (27). Larger multicenter series, such as that reported by Lykissas et al., further established that while immediate postoperative neurologic symptoms are common, persistent motor deficits are uncommon, occurring in approximately 3% of patients at final follow-up (46).

Radiographic outcomes from dual-position ldLLIF cohorts further support robust indirect decompression (39). In a study by Lee et al., the mean disc height increased significantly from 8.8±2.9 mm preoperatively to 15.4±2.4 mm postoperatively. This was accompanied by marked increases in bilateral foraminal area, with the ipsilateral side expanding from 99.5±31.1 to 159.2±44.8 mm² and the contralateral side increasing from 102.9±32.9 to 151.2±39.1 mm² (39). Furthermore, a successful radiographic fusion rate of 87.8% was observed at the 12-month follow-up (39). These radiographic improvements were associated with significant clinical gains, including a mean VAS reduction from 6.3±1.7 to 2.1±1.0 and an Oswestry Disability Index (ODI) reduction from 39.9%±16.5% to 11.1%±5.8% (39). Castellvi et al. demonstrated sustained 1-year improvements in radiographic parameters following staged ldLLIF with posterior fixation, including a 67% increase in mean disc height, 29–36% increases in foraminal area, and a 17% increase in central canal area (6). Similarly, these radiographic gains were accompanied by durable clinical improvements, as measured by VAS pain scores and ODI and no cases of radiographic pseudarthrosis or persistent postoperative neurologic deficits (6).

More recent ldLLIF literature increasingly reflects single-position lateral workflows, allowing clearer differentiation between workflow-related and positioning-related effects. Drazin et al. directly compared single-position and dual-position ldLLIF and demonstrated significantly shorter operative times with single-position surgery, which averaged 130.5 minutes compared to 190.3 min in the dual-position control group (23). Despite the gain in efficiency, estimated blood loss (108 vs. 93 mL), length of stay (3.8 vs. 4.1 days), and clinical improvement were found to be comparable between cohorts (23). Ziino et al. similarly reported substantial gains in operative efficiency with single-position ldLLIF, finding that dual-position procedures took longer (226.1 vs. 149.2 min) (44). Even after adjusting for the number of operating levels, single-position surgery resulted in an adjusted reduction in operative time of 44.4 minutes with no significant differences identified in global or segmental lordosis correction, estimated blood loss (109.2 vs. 116.7 mL), or length of stay (5.2 vs. 4.1 days) (44). While overall complication rates were similar, it was noted that 4.7% of patients (2 out of 42) in the single-position cohort required a re-intervention for symptomatic pedicle screws, compared to none in the dual-position cohort (44). Larger single-position ldLLIF series, including those reported by Blizzard and Thomas and by Ouchida et al., confirmed that operative efficiency improves with single-position workflows, while radiographic alignment gains and neurologic complication profiles remain similar to those observed in earlier dual-position cohorts (24,41). These findings suggest that some efficiency advantages attributed to pLLIF may reflect avoidance of repositioning rather than prone orientation alone.

pLLIF outcomes

Published pLLIF studies report significant improvements in patient-reported outcomes and radiographic parameters, with a growing emphasis on sagittal alignment correction and single-position workflow efficiency (Table 3). Early work by Godzik et al. demonstrated that prone lateral transpsoas access could be performed reproducibly, with a very low mean estimated blood loss of 19±14 mL and short mean retractor times of 15±6 min per level (3). Clinical results showed a significant improvement in ODI scores, which improved from 55.1±30.4 preoperatively to 28.5±18.0 postoperatively, and VAS back pain scores, which improved from 6.0±2.3 to 1.6±0.8 (P<0.001) (3). However, one case was converted to standard lateral positioning because the patient’s abdominal girth exceeded the capacity of the instruments and precluded the ability to safely palpate the psoas muscle (3).

Similarly, Soliman et al. reported significant improvements in functional outcomes, with mean ODI scores reducing from 57.6±12.1 to 35.3±21.6 and 12-Item Short Form Health Survey (SF-12) physical scores increasing from 24.8±8.7 to 35±11.2 (17). These clinical gains occurred alongside substantial radiographic improvements, including an increase in lumbar lordosis of 10.3°±8.5° and a 12.4°±8.8° reduction in pelvic incidence-lumbar lordosis (PI-LL) mismatch. However, pelvic tilt, sacral slope, and pelvic incidence remained unchanged, suggesting that prone positioning preferentially influences lumbar sagittal alignment rather than global pelvic parameters (17). As clinical experience expanded, larger series provide a clearer characterization of outcomes and complications. Farber et al. documented that immediate hip flexor weakness occurred in 21% of patients, though all resolved by 6-week follow-up (8). Radiographic evaluation at three months identified subsidence in 23% of patients with available 3-month imaging. Despite these approach-related findings, no major neurovascular injuries were observed (8).

Level-specific analyses have further refined neurologic risk stratification for the prone approach. In a focused L4–5 cohort, Morgan et al. demonstrated that ipsilateral thigh symptoms decreased substantially over time (from 34% at 6 weeks to 5% at 6 months) and that longer transpsoas retractor time was independently associated with early femoral nerve neurapraxia, emphasizing the importance of minimizing time-dependent neural compression even in the prone position (47). Longer-term outcome data have established the durability of these corrections; Singh et al. reported sustained one-year improvements in global and segmental lordosis, disc height, and multiple patient-reported outcomes (5). Although early hip flexor pain and weakness were common (affecting 46–59% of patients), femoral nerve palsy occurred infrequently (2%) and resolved by three months in all affected patients (5). A large contemporary series of 365 patients suggest that anterior longitudinal ligament (ALL) rupture (2.2%) and new neurologic symptoms occur at low but measurable rates, while persistent neurologic weakness remained uncommon (1.7%) and 90-day readmission rates are low (1.9%) (48).

Direct comparisons: ldLLIF vs. pLLIF

Direct comparative studies between ldLLIF and pLLIF provide significant clinical insights into the relative advantages of single-position workflows (Table 4). Buckland et al. conducted a multi-center study of 101 patients undergoing revision surgery and demonstrated that prone positioning achieved significantly shorter operative times (151 vs. 206 min) compared to dual-position ldLLIF (16). Despite the improved efficiency, estimated blood loss (150 vs. 182 mL) and 90-day complication rates (26.2% vs. 18.5%) were found to be similar between the cohorts, with no significant differences in postoperative radiographic alignment (16).

Rohde et al., in a pooled meta-analysis of 15 studies, similarly reported significant reductions in operative time and hospital length of stay with prone single-position LLIF when compared to dual-position cohorts (18). While estimated blood loss and rates of intraoperative or postoperative complications did not differ between the groups, prone positioning was found to be more effective at improving global lumbar lordosis (18). However, segmental lordosis and pelvic tilt remained similar across both surgical techniques (18).

Yung et al. provided further nuance by directly comparing single-position pLLIF with single-position ldLLIF, demonstrating significantly shorter adjusted operative times (207.2 vs. 317.5 min), reduced blood loss (244.5 vs. 376.3 mL), and shorter hospitalizations (3.1 vs. 3.6 days) in the prone cohort (19). Radiographically, they reported greater segmental lordosis gains across all levels from L1–S1 in the prone cohort, alongside a significantly higher rate of achieving predefined optimal outcomes at one year (96.6% vs. 78.5%) (19). In contrast, Sadhwani et al. reported similar median operative times (76–84 min), length of stay (1.4 days), and complication rates (~6%) between single-position ldLLIF and pLLIF (25). However, early postoperative ambulation distance on day 1 significantly favored the ldLLIF cohort (250 vs. 200 feet) (25).

Complications and neurologic considerations

Complication profiles for ldLLIF and pLLIF are dominated by approach-related neurologic events inherent to the transpsoas corridor originally described by Pimenta (51). Across both techniques, transient sensory disturbances and hip flexor weakness represent the most frequently reported adverse events, particularly at L4–5, where the lumbar plexus assumes a more anterior and caudal course (27,46,47). In ldLLIF cohorts, early postoperative sensory deficits have been reported in up to 38% of patients and motor weakness in approximately 24%, with the vast majority demonstrating partial or complete resolution over time (46). Persistent motor deficits are uncommon, typically occurring in fewer than 4% of patients at final follow-up (27,46). A summary of reported complication rates across ldLLIF and pLLIF series is provided in Table 5.

Learning curve effects are well documented in the ldLLIF literature and appear to significantly mitigate neurologic risk. Le et al. demonstrated a substantial reduction in postoperative sensory symptoms over time, which decreased from 26.1% to 10.7% as surgeon experience increased over a 3-year study period (27).

In pLLIF series, prone positioning results in posterior migration of the psoas muscle relative to the disc space, which has been proposed as a potential advantage for reducing lumbar plexus encroachment (3). Cadaveric and radiographic studies have quantified this effect, demonstrating that the femoral nerve moves posteriorly by an average of 10.1 mm with hip extension in the prone position, effectively enlarging the safe working corridor at L4–5 (7,20). Despite this anatomical shift, transient hip flexor weakness and thigh sensory symptoms remain common, reported in 17% to 59% of patients depending on the series and level treated (5,8). For example, Farber et al. reported immediate hip flexor weakness in 21% of patients, all of which resolved by 6 weeks (8). In a larger cohort of 97 patients, Singh et al. observed higher transient rates, with 59% experiencing hip flexor weakness and 46% reporting pain, though femoral nerve palsy occurred in only 2% of cases and resolved fully by 3 months (5). Formal learning curve analyses for pLLIF remain limited given the relative novelty of the technique. The wide range of reported transient neurologic symptoms, including upper-bound estimates exceeding 50% in some early series, may therefore reflect variability in surgeon experience and early adoption effects, similar to trends previously observed in ldLLIF literature.

Approach-related non-neurologic complications also warrant consideration, particularly regarding the integrity of the ALL. ALL rupture has been reported more frequently in pLLIF series, with Farber et al. reporting a rate of 7% and Soliman et al. reporting a rate of 2.2% in a multicenter series of 365 patients (8,48). A later pooled analysis by Farber et al. reported a similar ALL rupture rate of 2.3% across 10 studies (49). While often clinically silent or intentionally leveraged for lordotic correction, unintended ALL disruption carries implications for sagittal balance and cage stability.

Visceral and vascular injuries remain rare with both lateral ldLLIF and pLLIF. In large ldLLIF series and reviews, major vascular and bowel injuries are consistently reported at very low rates, typically well below 1% (1,52). Similarly, in a large multicenter pLLIF cohort, Soliman et al. reported a 0.3% vascular injury rate, which occurred during access for an adjacent anterior lumbar interbody fusion rather than during the transpsoas portion of the procedure, as well as a 0.3% ureteric injury rate (48). In a pooled analysis of pLLIF studies, Farber et al. identified a 2.0% incidence of segmental artery injury but reported no major vascular, peritoneal, or bowel injuries (49). Across available series, reported subsidence rates for pLLIF fall within the ranges historically described for ldLLIF and appear to be driven more by bone quality, endplate preparation, and interbody cage geometry than by patient positioning alone (48,49,53).

Instrumentation-related complications differ primarily by workflow rather than interbody approach. Dual-position ldLLIF introduces risks related to repositioning and prolonged operative time, whereas single-position ldLLIF and pLLIF aim to mitigate these factors. Brown et al. demonstrated significantly higher robotic pedicle screw placement accuracy in the prone position (98.1%) compared with lateral positioning (95.3%) (42). Despite this statistical difference, both groups maintained high success rates, and no screw breaches required surgical revision or resulted in clinical neurological deficits in either cohort (42).

Operative considerations and synthesis of ldLLF vs. pLLIF

Differences between ldLLIF and pLLIF are driven less by the interbody technique itself than by positional biomechanics, surgical workflow, and access to posterior instrumentation (3,18,44). A fundamental advantage common to both approaches is the ability to accommodate wide-footprint interbody cages that span the apophyseal ring, maximize fusion surface area, increase bone graft volume, and improve load sharing across the endplates. This implant geometry underlies the indirect decompression achieved with LLIF, facilitates segmental lordosis restoration, and has been associated with reduced subsidence risk, independent of patient positioning (6,45). When traditional dual-position ldLLIF workflows are compared with modern single-position ldLLIF techniques, many of the perceived advantages attributed to pLLIF are primarily driven by elimination of intraoperative repositioning, rather than by any intrinsic superiority of the prone orientation itself (12,19,44).

A principal operative distinction of pLLIF, as compared to dual-position ldLLIF, is its ability to support single-position circumferential surgery in the prone orientation, permitting interbody placement, posterior instrumentation/decompression, and revision maneuvers without a mid-case transition from lateral to prone positioning (3,18,26). This workflow advantage has been consistently associated with substantial reductions in operative time, anesthesia exposure, and operating room resource utilization. In a pooled meta-analysis, Rohde et al. reported mean operative times of approximately 103 minutes for pLLIF compared with 306 minutes for ldLLIF requiring repositioning (18). Cost analysis further supports this relationship. Lee et al. compared pLLIF with dual-position ldLLIF and demonstrated that, for two-level circumferential constructs, pLLIF reduced operating room utilization costs from $2,275 to $1,352 per case, along with lower anesthesia-related costs, $864 vs. $644 (14). These cost savings were achieved without differences in length of stay or short-term clinical outcomes (14). Importantly, when pLLIF is compared with single-position ldLLIF workflows, many of the efficiency and cost advantages attributed to prone positioning are attenuated, underscoring that these benefits are primarily driven by workflow consolidation rather than patient orientation alone (18,19,25,41,44).

From an alignment perspective, prone positioning facilitates segmental and global lordosis correction through gravity-assisted spinal extension and hip positioning (32,54). A substantial portion of this lordotic gain occurs prior to cage insertion, indicating that positioning itself contributes meaningfully to sagittal correction independent of implant geometry (32). As a result, pLLIF may reduce reliance on aggressive hyperlordotic cages or intentional ALL release in select patients with sagittal imbalance or flatback deformity (19,54).

Neurologically, prone positioning results in posterior migration of the psoas muscle and lumbar plexus, particularly at L4–5, effectively enlarging the anterior transpsoas working corridor (7,20). Cadaveric and imaging studies demonstrate posterior displacement of the femoral nerve on the order of approximately 10 mm with thigh extension, providing a plausible mechanistic rationale for corridor expansion (7,20). Nevertheless, transient approach-related neurologic symptoms remain common in both prone and lateral positions and appear more strongly influenced by retractor time, treated level, and surgeon experience than by positioning alone (5,27,47).

Despite these advantages, pLLIF introduces distinct technical challenges. The absence of table break limits intrinsic coronal bending, resulting in deeper working channels and potentially restricted access to L4–5 in patients with high iliac crests unless specialized positioning systems or bolstering techniques are employed (35,54). Visualization may also be hindered by gravitational soft tissue descent into the retractor field, particularly in patients with elevated body mass index, requiring careful retractor management and positioning adjustments (3,16).

In contrast, lateral decubitus positioning provides predictable coronal plane manipulation through table break and patient flexion, facilitating access to lower lumbar levels and improving rib–iliac crest clearance in patients with challenging anatomy (54). This positional flexibility remains an advantage of ldLLIF, particularly at L4–5 or in patients with large abdominal girth. ldLLIF also represents the historical standard for the LLIF approach, and familiarity with this position may allow experienced surgeons to limit retraction time and mitigate approach-related neurologic risk (27,36). However, when posterior spinal fixation is required, single-position ldLLIF may be relatively disadvantaged, as prone positioning more closely mirrors the orientation in which most surgeons are trained to place pedicle screws, potentially facilitating more efficient posterior instrumentation (26,42).

Emergency access represents a final operative consideration. Performing LLIF in the prone position may limit immediate anterior abdominal or cardiopulmonary access in the rare event of intraoperative emergencies, including vascular or visceral injury (35,48). While large contemporary series have not demonstrated increased rates of major complications with pLLIF, this theoretical limitation warrants acknowledgment and careful preoperative planning, particularly in complex or high-risk cases (48).

Strengths and limitations

This review synthesizes the most current literature on ldLLIF and pLLIF, incorporating several recently published comparative studies that were not included in prior reviews, thereby providing an updated and clinically relevant perspective. However, the available evidence remains limited by retrospective design, heterogeneity in workflow and indications, and incomplete long-term outcomes, which constrain the ability to draw definitive comparative conclusions. Additionally, as a narrative review, the synthesis is not based on a systematic meta-analytic framework, although care was taken to use a structured search strategy and critically appraise the available data.

Future directions

Single-position LLIF techniques, including both ldLLIF and pLLIF, are evolving, and future work will clarify the optimal integration of patient positioning and enabling technologies to improve clinical outcomes (26,29,55,56). Both ldLLIF and pLLIF appear to offer distinct advantages that merit further investigation (1,15,47,52,56).

A priority is improving the quality and comparability of the evidence base. Much of the current literature remains retrospective, single-surgeon, or heterogeneous in workflow and indications, limiting generalizability and confounding interpretation (46,49,50). Future studies should preferentially use multicenter prospective registries or pragmatic comparative designs that explicitly control for workflow (single-position vs dual-position), extent of posterior work (decompression, osteotomy, revision), and level-specific case mix, particularly inclusion of L4–5 and lumbosacral junction pathology when relevant (18,19,25). Importantly, comparative investigations should compare ldLLIF and pLLIF as separate single-position techniques (13,16,26,37,43).

Beyond positioning alone, technology is likely to be a key determinant as to whether single-position strategies can be broadly adopted with consistent reproducibility. Robotic navigation and advanced image guidance have been associated with high pedicle screw placement accuracy in single-position workflows, with reported accuracy rates approaching 98% in contemporary series (42,43). Importantly, these platforms may reduce position-specific technical constraints and standardize task execution across operative orientations. For surgeons adopting lateral single-position workflows, navigation and robotics may mitigate the technical challenges of lateral pedicle screw placement, while in prone workflows, these tools may support consistent interbody placement and trajectory control when the approach corridor, patient habitus, or positioning constraints reduce ergonomic flexibility (42,43,57). Early comparative data also suggest a learning curve for lateral-position instrumentation even with robotic assistance, with modestly higher rates of minor breaches reported in lateral compared with prone placement on computed tomography (CT) imaging, though without clinical sequelae in reported cohorts (31,42,57). Future work should therefore evaluate how platform selection, training protocols, and case complexity affect accuracy, radiation exposure, operative efficiency, and complication profiles across both single-position strategies (35,42).

In parallel, refinements in minimally invasive visualization and endoscopic adjuncts may expand indications for single-position LLIF and improve safety in anatomically constrained patients (28,34). Endoscopic-assisted approaches have been proposed to minimize psoas disruption, reduce retraction time, and permit targeted direct decompression when indirect decompression is insufficient, while maintaining the benefits of a lateral corridor (28,34). As these techniques mature, comparative studies should assess whether endoscopic or hybrid strategies reduce approach-related neurologic symptoms, shorten recovery, or improve functional outcomes relative to conventional workflows, particularly at higher-risk levels such as L4–5 (4,36,47).

Long-term outcomes remain a major evidence gap. Existing comparative studies are often underpowered for infrequent but clinically meaningful endpoints such as reoperation, pseudoarthrosis, and adjacent segment disease. Future prospective work should prioritize durability of alignment and fusion, as well as patient-centered outcomes beyond the early postoperative window (6,45,50). In particular, it remains unclear whether observed differences in lordosis restoration translate into differences in adjacent segment degeneration, mechanical complications, or longer-term health-related quality of life (26,32,50). Standardized complication reporting is also essential, especially for approach-related neurologic symptoms and ALL injury, as pooled analyses have emphasized variability in definitions and follow-up across available studies (49).

Finally, the economic impact of single-position LLIF should be quantified using rigorous value-based frameworks. Multiple studies suggest that eliminating intraoperative repositioning can reduce operating room time and length of stay, and some data demonstrate measurable operating room and anesthesia cost reductions in matched cohorts (13,14,16,23,41,44). These potential gains must be evaluated alongside the upfront and recurring costs of robotics, navigation, and endoscopic platforms, as well as the downstream impact on revision avoidance and healthcare utilization (31,35,49,58). Future trials should incorporate health economic endpoints including quality-adjusted life years, return-to-work intervals, total episode-of-care costs, and longer-term utilization to establish when technology-enabled single-position LLIF provides meaningful value over alternative strategies (49).

Conclusions

Both ldLLIF and pLLIF demonstrate reliable improvements in pain, function, and radiographic parameters, with favorable safety profiles across a broad range of degenerative lumbar pathologies. Perceived efficiency advantages of pLLIF over traditional dual-position workflows are largely attributable to elimination of intraoperative repositioning rather than prone orientation itself, and these differences are attenuated when compared to contemporary single-position ldLLIF. Position-specific biomechanics nonetheless remain clinically meaningful: prone positioning may facilitate sagittal alignment correction through gravity-assisted lumbar extension, while lateral decubitus positioning offers predictable coronal plane manipulation and may improve access in patients with challenging iliac crest anatomy or body habitus. Across both approaches, complication profiles are dominated by transient approach-related neurologic events that appear more strongly influenced by retractor time, surgeon experience, and treated level than by positioning alone. These findings support an indication-driven framework in which position selection is individualized based on patient anatomy, alignment goals, posterior procedural requirements, and surgeon experience, rather than a single universally preferred approach.

Acknowledgments

None.

Footnote

Provenance and Peer Review: This article was commissioned by the Guest Editor (Mitchell S. Fourman) for the series “Advances in Minimally Invasive Spine Surgery” published in AME Surgical Journal. The article has undergone external peer review.

Reporting Checklist: The authors have completed the Narrative Review reporting checklist. Available at https://asj.amegroups.com/article/view/10.21037/asj-25-69/rc

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