Category: MISS

Spine 2026;51(19):1381-1389

Access to L4-L5 during single-position lumbar fusion is shaped by the relationship between the disc, iliac crest, psoas, lumbar plexus and major vessels. Huynh and colleagues compare anterior lumbar interbody fusion performed in lateral decubitus with transpsoas lateral interbody fusion, examining whether the anterior route offers a useful alternative without repositioning the patient. Their multicenter findings associate lateral-position ALIF with fewer postoperative complications and greater segmental lordosis, while highlighting the importance of anatomical selection. The study expands the discussion of available corridors, but its observational design does not establish one approach as uniformly safer or more effective.

Objective

To compare complications, reoperations, procedural efficiency and sagittal alignment after L4-L5 lateral-decubitus ALIF (L-ALIF) and transpsoas LLIF during one- or two-level lateral single-position surgery.

Methods

The authors retrospectively reviewed prospectively and consecutively enrolled patients from seven surgeons across Australia, Brazil and the United States. The reported cohort comprised 511 patients: 72 undergoing L4-L5 L-ALIF and 439 undergoing L4-L5 LLIF. Mean ages were approximately 66 and 65 years, respectively. Indications included degenerative spondylolisthesis, foraminal stenosis and postlaminectomy instability or syndrome. Previous lumbar fusion, additional TLIF/PLIF, repositioning and staged surgery were excluded.

Approach selection depended on surgeon preference and anatomy. Three surgeons contributed L-ALIF cases, whereas all seven contributed LLIF cases. Additional fusion could involve L3-L4 using LLIF or L5-S1 using L-ALIF. Both groups received posterior pedicle instrumentation without changing the lateral position.

Follow-up was at least 90 days, with radiographic assessment at 90 days. Propensity matching for age, sex, BMI, diabetes, smoking and number of fused levels generated groups of 72 patients each. Complications were classified using the Clavien-Dindo system; neurological symptoms persisting beyond six weeks were classified as major complications.

Main results

In the matched groups, postoperative complications occurred in 4.2% after L-ALIF versus 19.4% after LLIF (p = 0.004); major complications were 2.8% versus 11.1% (p = 0.049). Ninety-day reoperations did not differ significantly (2.8% versus 8.3%; p = 0.146). Operating time, blood loss and length of stay were also similar after matching. L4-L5 segmental lordosis increased by 6.6° versus 1.8° (p = 0.003). Postoperative L4-S1 lordosis was greater with L-ALIF, but its change from baseline did not differ significantly. These are matched-cohort results, distinct from the larger unmatched comparison.

Interpretation

L-ALIF provides an alternative when the transpsoas corridor is constrained, but replaces plexus-related exposure concerns with vascular mobilization considerations. The study used an access surgeon for anterior exposure and EMG-guided mapping for LLIF; unsafe transpsoas docking prompted abandonment of that approach. These safeguards are part of the reported treatment setting, not optional details that the comparison can separate from outcomes. Importantly, the three vascular injuries in the overall LLIF-labeled group occurred during accompanying L5-S1 ALIF exposure, not the L4-L5 transpsoas approach. They cannot be attributed to LLIF itself.

Limitations

Treatment was not randomized, and the anatomical reasons for choosing each corridor were not adequately captured. Propensity matching balances measured variables but cannot remove this confounding by indication or the influence of surgeon experience. Only three surgeons supplied L-ALIF cases, compared with seven for LLIF.

Two-level operations combine different approaches, limiting attribution of complications to the L4-L5 corridor. Short follow-up and the absence of patient-reported functional outcomes prevent conclusions about durable symptom relief, fusion success or long-term revision risk. Absence of vascular injury in the 72 L4-L5 L-ALIF patients does not establish absence of risk. Multiple statistical comparisons also increase the possibility of false-positive findings, particularly for borderline results.

The publication contains minor reporting discrepancies, including 438 versus 439 LLIF patients in different locations and a segmental lordosis change of 6.8° in the abstract versus 6.6° in Table 5. The figures summarized here follow the main results and matched tables. Several authors disclosed industry relationships relevant to spinal instrumentation.

Clinical takeaway

For lateral single-position L4-L5 fusion, assess both the anterior vascular corridor and the transpsoas neural corridor before choosing the approach. L-ALIF is a reasonable option in experienced hands and may improve segmental lordosis while avoiding psoas-related symptoms. This study supports individualized planning, not a blanket claim that anterior access is safer or that greater radiographic correction guarantees better clinical recovery.

 

Neurosurgery. 2026;99(4):841-852

Severe lumbar canal narrowing does not necessarily identify a uniform surgical problem: reducible soft-tissue compression differs fundamentally from fixed osseous stenosis. Li and colleagues examine this distinction in a randomized comparison of oblique lateral interbody fusion and conventional transforaminal lumbar interbody fusion. Their findings support considering indirect decompression in carefully selected patients with instability, with perioperative advantages and earlier functional improvement after OLIF. However, the similar disability scores at two years, restrictive eligibility criteria and limitations in reporting argue against interpreting the study as evidence that indirect decompression can routinely replace direct neural decompression.

Objective

To compare clinical recovery, radiographic decompression, fusion and complications after OLIF and open TLIF for single-level severe lumbar stenosis with segmental instability.

Methods

The five-center trial assessed 260 patients and randomized 224 adults, 112 to each procedure, between November 2018 and December 2021. Allocation used computer-generated blocks and sequentially numbered sealed envelopes. Five experienced spine surgeons performed the operations. After five losses to follow-up, analyses included 109 OLIF and 110 TLIF patients with at least two years of follow-up.

Eligibility required symptomatic L2-L5 stenosis classified as Schizas C or D, radiographic instability, failure of at least three months of conservative treatment and a reducible, predominantly soft-tissue mechanism. Symptoms relieved by recumbency were an important selection feature. Fixed bony stenosis, ossified ligamentum flavum, ankylosis, sequestrated disc material, high-grade spondylolisthesis and unfavorable access anatomy were excluded, alongside several other conditions.

OLIF used a retroperitoneal corridor anterior to the psoas, interbody distraction and supplemental fixation. The comparator was conventional open TLIF with direct decompression, not minimally invasive TLIF. Outcomes included ODI, back and leg pain, serial canal measurements, alignment, CT-assessed fusion and complications.

Main results

OLIF had shorter operating time (102.8 versus 138.5 minutes) and lower estimated blood loss (24.8 versus 200.6 mL). ODI favored OLIF at three and six months, but not at two years (11.24 versus 11.95; p = 0.102). Two-year back pain scores favored OLIF; leg pain did not differ significantly. OLIF restored more disc height and segmental lordosis, whereas TLIF achieved greater canal area. Two-year fusion rates were 98.2% versus 95.5%, without significant separation. Recorded complications occurred in 6/109 OLIF and 8/110 TLIF patients; the difference was not significant.

Interpretation

The practical message is to assess whether compression is reducible, rather than choosing decompression solely from the Schizas grade. The OLIF protocol emphasized thorough disc clearance, preservation of the bony endplates, appropriate cage sizing and verification of implant position; endoscopic inspection was described as an adjunct. These components were not independently tested. Progressive canal enlargement after OLIF supports a remodeling mechanism, but does not establish that waiting for remodeling is appropriate for fixed compression or neurological deterioration. The findings support selective use, not a universal preference for OLIF.

Limitations

The trial studied a highly selected population treated by experienced surgeons at five Chinese centers. Its results do not establish effectiveness in multilevel disease, fixed osseous compression, deformity or high-grade spondylolisthesis. The open TLIF comparator also limits extrapolation to contemporary minimally invasive alternatives. Two years is insufficient to establish protection against adjacent-segment disease or long-term construct failure.

Although the authors describe the procedures as equivalent, the reported analysis does not specify an equivalence margin or a formal equivalence framework. A nonsignificant difference therefore should not be treated as proof of equivalence, particularly for uncommon complications. The report provides limited detail on sample-size justification, handling of repeated measurements and multiplicity; the presented analyses exclude the five patients lost to follow-up.

There is also an inconsistency in the description of OLIF fixation: the title and illustrations identify lateral vertebral fixation, whereas parts of the methods refer to pedicle screws and rods. This limits reproducibility of the exact construct. The early between-group ODI differences of approximately five points should not be confused with the larger within-patient improvement thresholds cited by the authors.

Clinical takeaway

Consider OLIF as an option for carefully selected, reducible single-level stenosis with instability when access anatomy and surgical expertise are suitable. This trial supports earlier recovery compared with open TLIF, but does not justify extending indirect decompression to fixed stenosis or claiming superior long-term function. Patient selection remains more important than canal grade alone.

Journal of Neurosurgery: Spine. 2026;45(3):339-346

Lumbar stenosis affecting adjacent levels does not necessarily imply that every symptomatic segment requires fusion. The operative challenge is to distinguish the level requiring stabilization from a neighboring stenotic segment that can be decompressed without compromising its mechanical integrity. Farooq and colleagues evaluate a hybrid strategy combining single-level minimally invasive transforaminal lumbar interbody fusion with adjacent-level unilateral laminotomy for bilateral decompression. Their experience provides preliminary clinical support for selective fusion in carefully chosen patients, while emphasizing that preservation of the adjacent segment depends on both preoperative stability and a structure-preserving decompression.

Objective

To assess reoperation after the one-and-a-half MIS-TLIF procedure, particularly subsequent extension of fusion to the adjacent decompressed segment, together with clinical and radiographic outcomes.

Methods

This retrospective single-center series evaluated operations performed by one experienced surgeon between January 2016 and February 2023. Of 36 patients considered, 33 met the inclusion criteria. Mean age was 67.9 years. Patients had degenerative lumbar disease with radiculopathy and mechanical back pain unresponsive to conservative treatment. The strategy combined MIS-TLIF using an expandable cage at the unstable segment with unilateral laminotomy for bilateral decompression (ULBD) at an adjacent stenotic level. The authors specify that adjacent-level decompression was restricted to segments without dynamic instability.

Outcomes included complications, reoperations, back and leg pain, disability and radiographic measures. Median clinical follow-up was 26 months. Complete serial imaging was available for 26 patients, with a median radiographic follow-up of 11.7 months. Fusion assessment relied primarily on standing and dynamic radiographs; CT was used when available rather than obtained routinely.

Main results

Three patients required reoperation (3/33, 9.1%). Two underwent extension of fusion to the previously decompressed adjacent level (2/33, 6.1%), while one underwent revision at the initially instrumented level. These are observed proportions over the reported follow-up, not comparative estimates of risk reduction.

Four patients experienced perioperative complications (12.1%): one CSF leak, one hardware failure, one wound dehiscence and one wound infection. No neurological complications were reported. Mean operative duration was 213.7 minutes, and median hospital stay was 48 hours. Blood loss was recorded in the categories below 50 mL or 50-150 mL in 28 of 33 patients.

Fusion was reported in 25 of the 26 patients with complete imaging (96.2%). Cage subsidence was present in six of these patients at the latest radiographic assessment (23.1%). Disc height and segmental lordosis improved; mean segmental lordosis increased from 14.1 degrees preoperatively to 17.4 degrees immediately after surgery and measured 16.4 degrees at final radiographic follow-up.

Pain and disability scores also improved. Median leg-pain VAS decreased from 5.5 before surgery to 0 at final follow-up. The final mean back-pain VAS was 3.1, compared with a preoperative median of 7.0. Final median ODI was 13.5, compared with a preoperative mean of 42.1. Because the paper reports a mixture of means and medians, these figures should not be subtracted and presented as a uniform average treatment effect.

Interpretation

The most useful surgical distinction is between adjacent stenosis and adjacent instability. This approach does not simply abbreviate a multilevel fusion: it assigns different treatments to levels with different mechanical requirements. The index level receives stabilization, while the adjacent level remains unfused only when it is radiographically stable and suitable for ULBD.

Preservation of the adjacent facets and posterior tension band is central to the rationale. A limited decompression designed to retain these structures cannot be considered mechanically interchangeable with a wide adjacent-level laminectomy. The authors distinguish this indication from bisegmental instability or foraminal stenosis requiring substantial facetectomy, situations in which a two-level fusion may address a different problem. The series does not validate a universal imaging threshold for selecting decompression alone.

The expandable cage introduces a separate technical consideration. The discussion emphasizes endplate preservation and controlled expansion, and the observed subsidence rate warrants attention even in the presence of a high reported fusion rate. Neither these data nor the accompanying illustration establish superiority of a particular cage design or an optimal expansion protocol.

The principal contribution is evidence of feasibility and early durability in a selected cohort. Two adjacent-level fusion extensions over a median of approximately two years are encouraging, but they do not demonstrate prevention of adjacent segment disease. The authors themselves caution that institutional single-level and two-level fusion series had different indications and follow-up periods and are contextual references rather than valid control groups.

Limitations

The study is small, retrospective and confined to one highly experienced surgeon, without a comparative control group. Selection limits applicability to patients with instability at more than one level, high-grade spondylolisthesis, epidural fibrosis or advanced osteoporosis. Seven patients lacked complete serial imaging, and fusion was not routinely confirmed with CT. Clinical and radiographic follow-up durations differ substantially, and the longer-term risk of adjacent-level deterioration remains uncertain. Absence of neurological complications in 33 patients cannot establish a negligible risk. Comparative advantages in morbidity, reoperation or motion preservation remain unproven.

Clinical takeaway

Consider selective fusion as a question of segment-specific pathology: stabilize the level that requires it and assess whether an adjacent stable stenotic level can be adequately decompressed while preserving its supporting structures. This series supports discussing one-and-a-half MIS-TLIF as an option in appropriately selected patients, with explicit counseling about possible later fusion extension. It does not support substituting limited decompression for fusion at a second genuinely unstable segment.

The Spine Journal 26 (2026) 85−93

This single-center pilot randomized controlled trial compares posterior midline versus posterior paramedian (Wiltse/minimally invasive) approaches for 1–2 level lumbar interbody fusions, assessing feasibility, infection rates, and reoperation. One hundred-one patients were randomized, with reported differences: higher deep infection (9.6% vs 4.1%) and greater reoperation rates (25% vs 6.1%) in the midline group, alongside improvements in PROMs for both groups.

Methods, perioperative care, and outcome measures are detailed, including CDC-defined deep infection, PROMs (ODI, SF-12, EQ-5D, VAS), and feasibility metrics for a multicenter RCT. The authors conclude the pilot supports a larger trial, recommend an interim analysis for reoperation differences, and outline limitations related to single-surgeon data, recruitment disruptions, and clustering effects.

Pilot RCT Findings: A single-center pilot randomized controlled trial compared posterior paramedian and midline incisions for lumbar interbody fusion, finding potential differences in deep infection and reoperation rates, with both groups showing improvement in patient-reported outcomes.

Infection Rates: Deep infection occurred in 9.6% of midline patients versus 4.1% in the paramedian group within 3 months post-surgery.

Reoperation Rates: 25% of midline patients required revision surgery compared to 6.1% in the paramedian group during follow-up.

Patient Outcomes: Both surgical approaches led to improvements in disability, pain, and quality of life scores at 6–18 weeks and 1 year postoperatively, with slightly greater improvements noted in the paramedian group.

Intraoperative Metrics: The paramedian group had lower average blood loss (268ml vs. 313ml) and a shorter average hospital stay (3.3 vs. 4.2 days) compared to the midline group.

Feasibility: The trial demonstrated high protocol adherence, low loss to follow-up, and good participant acceptance, supporting the feasibility of a larger multicenter RCT.

Limitations: The pilot was limited by single-center design, small sample size, protocol violations, and short follow-up; results may not be generalizable until confirmed by a larger trial.

Next Steps: The pilot data will inform sample size calculations and study design for a multicentered RCT to clarify whether paramedian approaches offer significant clinical advantages over midline incisions.

Operative Neurosurgery 29:624–632, 2025

This clinical study evaluates whether “Banana” versus “Bullet” transforaminal lumbar interbody fusion (TLIF) devices produce different immediate postoperative segmental lordosis in one- and two-level degenerative lumbar fusions. Using 241 treated levels from 198 patients, the authors compare radiographic outcomes and perform multivariable regression to identify independent predictors of postoperative segmental lordosis and its change.

Findings show univariable advantages for “Banana” cages in small magnitudes, but multivariable analysis identifies preoperative segmental lordosis, implant-listed lordosis, pelvic incidence, and use of bilateral TLIF windows—not cage morphology—as primary predictors of immediate postoperative segmental correction. The paper recommends further work on subsidence risk and maintenance of correction.