Tag: Lumbar

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Is the chin-brow vertical angle always a reliable parameter for surgical planning in the correction of thoracolumbar kyphosis secondary to ankylosing spondylitis?

J Neurosurg Spine 44:858–865, 2026

This clinical retrospective study evaluates whether the chin-brow vertical angle (CBVA) reliably predicts the osteotomized vertebra angle (OVA) when planning pedicle subtraction osteotomy for thoracolumbar kyphosis secondary to ankylosing spondylitis. Patients were stratified by cervical range of motion (CROM) and radiographic changes in CBVA, cervical Cobb angles, and global sagittal parameters were analyzed.

Results show a strong correlation between ΔCBVA and OVA in patients with limited CROM (≤20°), but no correlation when CROM exceeded 20°, indicating that CBVA alone is unreliable for OVA design in patients with flexible cervical spines. The study recommends considering cervical mobility when selecting OVA planning methods and suggests supplementing CBVA with measures of cervical compensation in flexible cases.

Objective Examine how well CBVA predicts needed correction (OVA) in ankylosing spondylitis (AS) thoracolumbar kyphosis across different cervical range of motion (CROM) values.

Design/Groups Retrospective cohort of AS patients undergoing single-level thoracic or lumbar pedicle subtraction osteotomy (PSO) (2015–2019) with ≥2-year follow-up; grouped by CROM: ≤10°, 10–20°, and >20°.

Key finding (CROM ≤20°) Strong correlation between ΔCBVA (preop→immediate postop) and OVA in CROM ≤10° and 10–20° groups (r = 0.881 and 0.932; both p < 0.001), supporting CBVA-based planning when cervical motion is limited.

Key finding (CROM >20°) No correlation between ΔCBVA and OVA when CROM > 20° (r = 0.198, p = 0.314), and most patients (89%) had ΔCBVA smaller than OVA, implying undercorrection risk if CBVA alone guides OVA.

Cervical adaptation mechanism With higher cervical mobility, postoperative cervical alignment changes substantially (CNA group cervical kyphosis change 20.25° vs 4.97° in CA), which can blunt CBVA change despite large osteotomy correction.

Improved predictor Adding cervical alignment change (ΔCobb C0–7) to CBVA change yields closer agreement with OVA (ΔCobb C0–7 + ΔCBVA correlated with OVA in both CA and CNA groups; CA r = 0.87 p < 0.001; CNA r = 0.38 p = 0.044).

Clinical recommendation CBVA is not consistently reliable for OVA design; it is not recommended as a guiding parameter when CROM > 20°.

Outcomes Both cervical-ankylosis–range (CROM ≤20°) and nonankylosis–range (CROM >20°) subgroups achieved satisfactory orthopedic improvement after surgery despite differences in cervical compensation.

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Incidence and risk factors of adjacent segment degeneration in lumbosacral or lumbo-iliac fusion with L2 as the uppermost instrumented vertebra

J Neurosurg Spine 44:693–703, 2026

This clinical retrospective study evaluates the incidence and risk factors for symptomatic adjacent segment degeneration (ASD) after instrumented fusion from L2 to the sacrum or ilium in 89 adults treated for diffuse lumbar degeneration or mild–moderate deformity. Over a mean 38.6-month follow-up, 40% developed symptomatic L1–2 ASD and 23.6% required revision, with Kaplan-Meier ASD-free rates of 79% at 1 year and 59% at 3 years.

Multivariate analysis identified L2–3 decompression, preexisting advanced L1–2 disc degeneration, greater postoperative PI–LL mismatch, and higher lordosis distribution index as independent ASD risk factors; distal failures (13.5%) were linked to male sex, younger age, and absence of iliac screws. The authors recommend careful selection of L2 as UIV, balanced lordosis restoration, and consideration of pelvic fixation to mitigate proximal and distal complications.

Aim Quantify incidence of symptomatic adjacent segment degeneration (ASD) after instrumented fusion from L2 (UIV) to sacrum or ilium and identify associated risk factors.

Design/definition Retrospective review (Jan 2016–Dec 2023) of adults undergoing first-time L2–S1/ilium fusion; symptomatic ASD defined by new/worsening pain or neurologic symptoms with L1–2 degenerative/junctional changes (e.g., disc degeneration/stenosis progression, listhesis, junctional kyphosis, fracture, or UIV fixation failure).

Cohort 89 patients (mean age 68.5 years) with mean follow-up 38.6 months.

ASD incidence 36/89 (40%) developed symptomatic ASD at L1–2; mean time to ASD 21 months; 21/89 (23.6%) required reoperation.

ASD-free survival Kaplan-Meier ASD-free rates: 79% at 1 year, 68% at 2 years, 59% at 3 years (mean ASD-free period 52.8 months).

ASD risk factors Higher ASD risk associated with simultaneous decompression at L2–3, preexisting advanced L1–2 disc degeneration, greater postoperative PI-LL mismatch, and higher lordosis distribution index (LDI).

Distal failure incidence 12/89 (13.5%) developed distal failure (including 9 L5–S1 pseudarthroses, 2 sacral fractures, 1 rod fracture); mean time 19 months.

Distal failure risk factors Male sex, younger age, and lack of iliac screws increased risk of distal failure.

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Impact of lateral plate and screw fixation on long-term radiographic subsidence in lateral lumbar interbody fusion

J Neurosurg Spine 44:493–497, 2026

This clinical study evaluates long-term radiographic subsidence after lateral lumbar interbody fusion (LLIF), comparing stand-alone procedures with those augmented by lateral plate and screw fixation. Retrospective analysis of 146 patients (219 levels) with ≥1-year CT follow-up shows lateral plating significantly reduced subsidence odds, while 3D-printed porous titanium cages trended toward lower subsidence than PEEK.

Results note similar reoperation rates between groups, no grade III subsidence, and rare adverse events including one delayed vertebral fracture with plating; methodology included multivariate logistic regression and Marchi subsidence grading. Conclusions support lateral plate and screw fixation, particularly with porous titanium cages, as protective against severe radiographic subsidence.

Objective Assess whether adding lateral plate and screw fixation changes the long-term rate/grade of radiographic cage subsidence after LLIF (excluding posterior instrumented fusion).

Design/Population Retrospective review (2014–2022) of degenerative lumbar spondylosis LLIF cases at two centers; required ≥1-year postoperative CT; 146 patients/219 levels (45% plated, 55% stand-alone).

Subsidence grading Long-term imaging graded by Marchi criteria (grade 0: 0%–24% disc height loss; I: 25%–49%; II: 50%–74%; III: 75%–100%); no intraoperative subsidence included.

Main finding (plating effect) Lateral plate + screws was significantly associated with reduced long-term radiographic subsidence (multivariable OR 0.484, p = 0.006).

Severity pattern All grade II (severe) subsidence cases occurred in the stand-alone LLIF group (4 patients); no grade III subsidence observed.

Cage material trend 3D-printed porous titanium cages trended toward lower subsidence versus PEEK but did not reach statistical significance (OR 0.401, p = 0.071).

Reoperation/fusion No significant difference in reoperation rate between plated and stand-alone groups; radiographic fusion rates were similar (83.1% plated vs 86.4% stand-alone; p = 0.58).

Noted complications/implant details One lateral-plate patient had a delayed vertebral body fracture; plated cases used 18-mm-wide cages, while nearly all stand-alone cases used 22-mm-wide cages.

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Utilization of robotic pars repair for early return to activity in adolescents with symptomatic spondylolysis

J Neurosurg Spine 44:349–354, 2026

This case series from a tertiary academic spine center reports outcomes of robot-assisted percutaneous pars repair in nine adolescents with symptomatic lumbar spondylolysis who failed conservative management. The authors describe a single–midline incision technique using CT-based robotic guidance and a single lagged transdefect screw, detailing operative workflow, implant sizes, and a standardized postoperative rehabilitation protocol.

Results show most patients returned to preinjury or higher activity within months, with low complication rates and radiographic evidence of union in those who obtained CT follow-up. The authors conclude that minimally invasive robotic pars repair is a viable option after failed nonoperative care and advocate timely surgical consultation to potentially accelerate return to sport and avoid progressive spondylolisthesis.

Clinical problem Symptomatic lumbar pars interarticularis fractures (spondylolysis) are a common cause of adolescent low-back pain; nonoperative care with activity modification is standard first-line treatment.

Nonunion risk Despite conservative management, about 20% of patients may progress to symptomatic nonunion, and some can later develop spondylolisthesis that may require fusion.

Study aim Robotic surgical guidance was used to enable percutaneous pars screw placement; the series reports the largest cohort of adolescents treated with robot-assisted pars repair to date.

Design & cohort Retrospective review of a prospectively collected database identified 9 adolescents/young adults (13–25 years) treated with a single-screw pars repair technique.

Technique Using Excelsius robotic planning/registration and intraoperative 3D imaging, bilateral screw trajectories were planned to converge so bilateral pars screws could be placed through a single 1–2 cm midline incision; compression was achieved via a “lag-by-technique” preparation without direct pars visualization/grafting.

Postop protocol Patients walked only for 2 weeks, then added stationary biking for 2 weeks, followed by 4 weeks of sport-directed physical therapy; if tolerated symptom-free, they were cleared for activity (cleared to begin return-to-sport training at 4 weeks).

Outcomes Mean preop activity cessation at consultation was 8.6 ± 10.6 months; at mean follow-up 11.4 ± 9.1 months, 78% had returned to baseline activity or were cleared to return to sport.

Safety/efficacy conclusion Robot-assisted pars repair was reported as a safe, effective option after failed nonoperative care, enabling return to activity in as little as 8 weeks; a single lag-style screw may be clinically effective compared with prior open debridement/bone-grafting approaches.

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Do all patients with adult scoliosis need instrumented fusion from T10 to the pelvis?

J Neurosurg Spine 44:195–204, 2026

This clinical review addresses whether adult scoliosis uniformly requires instrumented fusion from T10 to the pelvis, presenting diagnostic frameworks, radiographic assessment, and surgical decision-making. It contrasts full-length thoracolumbar–pelvic constructs with shorter, focal interventions, emphasizing individualized selection based on pain generators, balance, deformity location, and comorbidities.

The article reviews indications for extending fusions to upper thoracic levels, risks such as proximal junctional kyphosis, and evidence supporting limited fusion or decompression-only strategies when focal pathology (fractional curve, foraminal stenosis, olisthesis) explains symptoms. Multiple case examples illustrate practical application of the decision algorithm and outcomes.

Individualized Treatment: Not all adult scoliosis patients require instrumented fusion from T10 to the pelvis; surgical decisions should be based on the patient’s symptoms, pain generator, spinal balance, and radiographic findings rather than a one-size-fits-all approach.

Pain Source Identification: Careful identification of the pain generator (scoliosis-related, neurogenic, facet, or sacroiliac) is critical; many patients have back pain unrelated to scoliosis and may benefit from focal or limited procedures instead of extensive fusion.

Fusion Level Selection: The choice of upper instrumented vertebra (UIV) depends on curve characteristics, presence of kyphosis, risk of proximal junctional kyphosis (PJK), and patient-specific factors; fusion may end at T10, upper thoracic, or even lumbar levels as appropriate.

Limited/Focal Surgery: In select cases, limited fusion (e.g., of the major curve, concavity, or fractional curve) or even decompression alone can be effective, especially for patients with focal symptoms or significant comorbidities who cannot tolerate extensive surgery.

Fractional Curve Fusion: Fusion of only the fractional curve (typically L4–S1) is effective for radicular pain referable to this segment; careful preoperative assessment of coronal alignment and curve type is necessary to avoid postoperative imbalance.

Radiographic-Clinical Correlation: Surgical planning should integrate both radiographic parameters (sagittal vertical axis, pelvic incidence–lumbar lordosis mismatch, coronal balance) and the patient’s clinical presentation, as discordance may require further investigation.

Risks of Extensive Fusion: Long-segment fusions (T10–pelvis or longer) carry significant morbidity and complication risks; such approaches are best reserved for cases with severe, disabling symptoms, progressive deformity, or global imbalance.

Patient Preferences and Expectations: Surgical decisions must consider patient quality of life, goals, psychological profile, and willingness to accept surgical risks or possible reoperation, with shared decision-making emphasized

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Intraoperative vancomycin for preventing infection after open spine surgery: a systematic review and meta-analysis of randomized controlled trials

J Neurosurg Spine 43:509–518, 2025

A meta-analysis of seven randomized controlled trials found that intraoperative vancomycin use in open spine surgery did not significantly reduce rates of superficial or deep surgical site infections. Further large-scale studies are needed to clarify its efficacy and inform clinical guidelines.

• A systematic review and meta-analysis of 7 randomized controlled trials (RCTs) with 2235 patients assessed the efficacy of intraoperative vancomycin in preventing infections after open spine surgery.

• No significant reduction in overall surgical site infections (SSI), deep infections, or superficial infections was found with intraoperative vancomycin compared to control.

• Subgroup analyses showed no benefit in either instrumented or uninstrumented spine surgeries.

• There was no significant shift toward gram-negative or culture-negative infections with vancomycin use.

• Potential risks include local cytotoxicity and possible impairment of bone healing and spinal fusion.

• Current evidence is limited by small sample sizes, heterogeneity in vancomycin administration, and variable follow-up durations.

• The study concludes intraoperative vancomycin may not reduce infection risk and further large RCTs are warranted.

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Outcomes After Decompression Only Versus Decompression and Fusion for Lumbar Facet Cysts: A Systematic Review and Meta-Analysis

Neurosurgery 97:536–544, 2025

This meta-analysis compared decompression only (DO) versus decompression and fusion (DF) for lumbar facet cysts. DF reduced cyst recurrence and improved back pain resolution but had longer hospital stays. Reoperation and radiculopathy resolution rates were similar between groups. Most studies lacked standardized criteria for choosing DF over DO.

• Lumbar facet cysts (LFCs) are associated with facet degeneration and segmental instability; surgical management is debated between decompression only (DO) and decompression with fusion (DF).

• This systematic review and meta-analysis included 9 comparative studies with 3393 patients (DO: 1940, DF: 1453).

• Spondylolisthesis rates were significantly higher in the DF group (65.8% vs 24.3% in DO).

• DO had higher odds of cyst recurrence (6.3% vs 0%) and lower odds of back pain resolution (56.6% vs 74.5%) compared to DF.

• Reoperation rates (DO 7.2%, DF 5.9%) and radiculopathy resolution (DO 77.3%, DF 87.2%) were similar between groups.

• Length of hospital stay was shorter in the DO group.

• Criteria for choosing DF vs DO varied and were often not clearly defined across studies.

• The study concludes DF reduces cyst recurrence and improves back pain resolution but has longer hospital stays; reoperation and radiculopathy outcomes are comparable.

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Prone Lateral Transpsoas Approach to the Spine: A Technical Guide for Mastery

Int J Spine Surg 2025, 19 (S1) S19-S27

• The prone lateral transpsoas (PTP) approach offers an alternative to traditional lateral lumbar interbody fusion (LLIF), allowing direct posterior access without repositioning the patient.

• Advantages of PTP include improved segmental lordosis, single-position surgery, and ease of posterior techniques, though it has a distinct learning curve.

• The technical guide aims to shorten the learning curve, optimize surgical workflow, and ensure patient safety through preoperative planning and technical adjustments.

• Preoperative imaging is crucial for assessing anatomical characteristics and guiding surgical approach decisions.

• Patient positioning in PTP involves prone positioning on a radiolucent table, with special attention to stabilizing the pelvis and optimizing working angles.

• Intraoperative monitoring with triggered electromyography (t-EMG) is essential to minimize lumbar plexus injury risk.

• Technical pearls include strategies for retractor positioning, minimizing retraction time, and using intraoperative navigation to enhance safety and efficiency.

• Conclusion: PTP LIF is a viable alternative to traditional methods, offering significant benefits but requiring mastery of its unique technical nuances.

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Outpatient lateral lumbar interbody fusion: single-institution consecutive case series

J Neurosurg Spine 42:140–146, 2025

Outpatient spine surgery could reduce hospital costs and improve patient outcomes. Outpatient lateral lumbar interbody fusion (LLIF) can be performed for select patients. This study identified and compared the demographic, clinical, and surgical characteristics of patients who underwent outpatient versus inpatient single-level LLIF.

METHODS A retrospective review was conducted of a prospectively collected database of patients who underwent first-time single-level LLIF at a single institution performed by the same surgeon from January 1, 2017, through December 31, 2022. Demographic characteristics, including age, sex, BMI, and medical comorbidities, were collected. Surgical factors, such as level of surgery, operative duration, and estimated blood loss, were also collected. Length of stay and 30-day readmission were the primary outcomes of interest. Patients discharged on the day of surgery or the following day were considered to be in the outpatient group. ANOVA and chi-square tests were performed to compare continuous and categorical variables, respectively. Univariate logistic regression was used to examine the correlation between baseline demographic and surgical variables and outpatient surgery. If a variable significantly correlated with outpatient surgery on univariate analysis, it was subsequently used in multivariate logistic regression.

RESULTS A total of 107 patients underwent first-time single-level LLIF, and 48 (44.9%) did not have posterior instrumentation. Fifty-three (49.5%) patients were women. The median age and BMI were 66.3 years and 28.9, respectively. The mean length of stay was 1 day (range 0–4 days), with 71 (66.4%) of 107 single-level LLIFs managed on an outpatient basis. There were no readmissions within 30 days. Patients in the outpatient group were more likely than patients in the inpatient group to be male (59% [42/71] vs 25% [9/36], p = 0.002), have a low LACE (risk criteria based on length of stay, acuity of the admission, comorbidity of the patient, and emergency department use within 6 months before admission) readmission index (63% [45/71] vs 28% [10/36], p < 0.001), and have a stand-alone construct (62% [44/71] vs 11% [4/36], p < 0.001). The outpatient cohort also had a shorter mean operative duration (104.4 vs 175.5 minutes, p < 0.001) and lower mean estimated blood loss (20 vs 100 mL, p < 0.001). There was no difference in age between the groups. Factors that remained significant on multivariate logistic regression were male sex (OR 0.14, 95% CI 0.04–0.53; p = 0.004), lower LACE readmission index (OR 0.06, 95% CI 0.02–0.25; p < 0.001), and stand-alone construct (OR 8.17, 95% CI 1.49–44.74; p = 0.02).

CONCLUSIONS Multiple baseline and surgical characteristics were more common in the outpatient setting. With appropriate patient selection, single-level LLIF can be achieved on an outpatient basis.

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How Do the True Intraoperative Costs of Endoscopic Diskectomy Compare With Microdiskectomy for Lumbar Disk Herniations?

Operative Neurosurgery 27:690–697, 2024

Endoscopic lumbar diskectomy (ED) is a minimally invasive option for addressing lumbar disk herniations. With the introduction of value-based care systems, assessing the true cost of certain procedures is critical when creating reimbursement models and comparing procedures. Here, we compared the costs of performing a microdiskectomy (MD) and ED using time-driven activity-based costing.

METHODS: Total cost for the intraoperative episode was calculated using time-driven activity-based costing methodology. Individual costs were obtained by direct observation and electronic medical records and through querying multiple departments (business operations, sterile processing, plant operations, and pharmacy). Timestamps for all involved personnel and material resources were documented. A retrospective analysis was performed on 202 patients who underwent lumbar diskectomy through either MD (n = 167) or ED (n = 35) from 2018 to 2022. Personnel cost was calculated by multiplying the cost per unit time for each personnel type by the length of time spent in the operating room. Supply cost was calculated by aggregating the cost of all individual supplies, from medications to consumables to surgical trays, used during the case. Univariate and multivariable regression analyses were performed comparing the costs between these procedures.

RESULTS: The average intraoperative cost per case for ED and MD was $3915 ± $1025 and $3162 ± $954, respectively. Multivariable regression analysis revealed that ED had higher total cost ( β -coefficient: $912 ± $281, P = <.01) and supply cost ( β -coefficient: $474 ± $155, P = <.01) than MD. When accounting for surgeon as a covariate, however, total cost (P = .478) and supply cost (P = .468) differences between ED and MD were negligible.

CONCLUSION: ED has shown to be a better value option in addressing lumbar disk herniations, mostly because of advantages in perioperative care. Here, we show that when correcting for surgeon-level effects, the cost between the two procedures is statistically insignificant, reaffirming the value provided by ED.

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Impact of bilateral facet joint violation on radiographic degeneration of superior adjacent segments and clinical outcomes

J Neurosurg Spine 41:1–8, 2024

Facet joint violation (FJV) is associated with postoperative low-back pain and is a confirmed risk factor for adjacent-segment degeneration, a long-term complication of lumbar fusion surgery. The authors’ knowledge of its mechanisms comes from in vitro biomechanical research only; there is a lack of radiographic evidence of the effects of violation on the superior adjacent-segment facet joint, intervertebral disc, and other local radiographic parameters. Furthermore, any differences between unilateral and bilateral violation remain relatively unclear. The authors therefore aimed to explore the effects of nonviolation and unilateral and bilateral violation on radiographic degeneration of the facet joint and intervertebral disc at the fusion and superior adjacent segment. Patient-reported clinical outcomes were compared at the 2-year follow-up.

METHODS The authors retrospectively analyzed data from 148 patients with lumbar degenerative diseases who underwent single-segment minimally invasive transforaminal lumbar interbody fusion between 2016 and 2020. FJV and facet joint degeneration were evaluated and graded using Shah’s method and Pathria’s standard, respectively. Radiographic parameters, including disc height and intervertebral Cobb angle at the fusion and superior adjacent segment, were measured. Clinical outcomes were evaluated using visual analog scale (VAS) and Japanese Orthopaedic Association scores.

RESULTS Preoperative data were comparable among the 3 groups (nonviolation, unilateral violation, and bilateral violation) (p > 0.05). Patient-reported clinical outcomes were followed up for at least 2 years (average duration 28.17 ± 6.17 months). At the last follow-up, facet joint degeneration grades were sequentially increased in the nonviolation, unilateral violation, and bilateral violation groups (p = 0.006). The unilateral (2.45 ± 2.17 mm) and bilateral (2.70 ± 1.94 mm) violation groups had more severe losses of disc height in the superior adjacent segment than did the nonviolation group (1.31 ± 2.01 mm). The VAS low-back pain and Japanese Orthopaedic Association scores in the bilateral (2.57 ± 1.44 and 19.83 ± 2.84, respectively) and unilateral (2.26 ± 0.79 and 20.43 ± 3.85, respectively) violation groups were significantly worse than in the nonviolation group (1.69 ± 1.12 and 21.80 ± 3.36, respectively) (p < 0.05). By contrast, there were no significant between-group differences in disc height, intervertebral Cobb angle in the fusion segment, or VAS leg pain scores (p > 0.05).

CONCLUSIONS FJV was associated with postoperative low-back pain and worse functional outcomes. It also aggravated facet joint and intervertebral disc changes in the superior adjacent segment, especially when bilateral violation occurred; this may be part of the mechanisms of adjacent-segment degeneration.

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A novel approach to evaluation of lumbar bone density using Hounsfield units in volume of interest on computed tomography imaging

J Neurosurg Spine 40:708–716, 2024

The purpose of this retrospective study was to evaluate the relationship between bone mineral density (BMD), as assessed with dual-energy x-ray absorptiometry (DEXA), and Hounsfield units (HU) measured in volumes of interest (VOIs) and regions of interest (ROIs) on lumbar spine CT.

METHODS A retrospective analysis was performed on data of lumbar vertebrae obtained from patients who underwent both DEXA and lumbar spine CT scan within a 6-month period. Vertebrae with a history of compression fracture, infectious spondylitis, cement reinforcement, or lumbar surgery were excluded. HU measurements were performed in the VOI and ROI (midaxial, midcoronal, and midsagittal sections) with CT, whereas BMD was assessed with DEXA. Statistical analyses, including correlation assessments and receiver operating characteristic (ROC) curve analyses, were performed.

RESULTS This analysis included 712 lumbar vertebrae, with a median patient age of 72.0 years. BMD values and HU measurements in the VOI increased sequentially from L1 to L4, whereas HU values in the ROI did not show a consistent pattern. HU values in the VOI consistently showed a stronger correlation with BMD than those in the ROI. ROC analysis revealed patient-level cutoff values for the diagnosis of osteoporosis at different lumbar vertebral levels with high sensitivity and specificity, as well as an excellent area under the curve.

CONCLUSIONS This is the first study to introduce a novel approach using the HU value in the VOI to assess bone health at the lumbar spine. There is a strong correlation between the HU value in the VOI and BMD, and the HU value in the VOI can be used to predict osteoporosis.

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Hospital cost differences between open and endoscopic lumbar spine decompression surgery

J Neurosurg Spine 40:77–83, 2024

In recent years, fully endoscopic decompression surgery for degenerative spine disease has become increasingly popular in the US. Although an endoscopic approach has demonstrated some benefits compared with open procedures in randomized controlled trials, the cost of advanced technologies remains contested. The authors evaluated the differences in costs and cost drivers between open and endoscopic decompression surgical procedures performed at a single institution.

METHODS Using associated Current Procedural Terminology codes, the authors identified all open and endoscopic decompression lumbar surgical procedures performed from January 1, 2016, through December 31, 2022. Preoperative comorbidities, surgical characteristics, and postoperative outcomes were captured. The costs of index surgery–related readmission for revision, washout, or other complications were included in the index surgery expenses. Associated inhospital costs were collected; these were reported in comparative percentages with open surgical procedures as the baseline because of an institutional agreement. Univariate and multivariate analyses were performed.

RESULTS The retrospective search identified 633 open surgical procedures and 195 endoscopic surgical procedures for inclusion. The two patient cohorts were similar, with clinically nonrelevant but statistically significant differences in mean age (open 55.7 years vs endoscopic 59.4 years, p = 0.01) and mean American Society of Anesthesiologists physical status class (open 2.3 vs endoscopic 2.4, p = 0.03). Postoperatively, patients who underwent open surgical procedures had significantly longer mean hospital stays (open 1.4 days vs endoscopic 0.7, p < 0.01) and more perioperative complications (open 7.9% of patients vs endoscopic 3.1%, p = 0.02), and they required washout surgical procedures in some cases (open 1.3% vs endoscopic 0%, p = 0.12). The largest cost difference between open and endoscopic surgical procedures was the significantly greater cost of disposable supplies for endoscopic cases (10.1% vs 31.7% of the total cost of open procedures, p < 0.01), and open surgical procedures were generally less costly in total (100.0% vs 115.1%, p < 0.01). In multivariate linear regression, endoscopic surgery was independently associated with greater total costs (standardized beta 15.9%, p < 0.01), although length of hospital stay (standardized beta 34.0%) and readmissions (standardized beta 30.0%, p < 0.01) had larger effects on cost.

CONCLUSIONS The endoscopic approach was associated with greater total in-hospital costs compared with open procedures. The findings of further cost evaluations, including those of patient-reported outcomes, social cost, and capital costs per procedure type, need to be included in operational and clinical decisions.

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Midline lumbar interbody fusion: a review of the surgical technique and outcomes

J Neurosurg Spine 39:462–470, 2023

Midline lumbar interbody fusion (MidLIF) is a mini-open posterior interbody fusion technique defined by a cortical screw trajectory wherein screws are placed from a more medial to lateral trajectory compared with traditional pedicle screws. This enables the surgeon to perform a smaller muscle dissection with the benefits of improved blood loss, less muscle retraction, decreased operative time, shorter length of stay, and improved back pain outcomes compared with the traditional posterior lumbar interbody fusion techniques utilizing pedicle screw fixation.

Importantly, MidLIF offers comparable clinical outcomes and radiographic outcomes to other posterior lumbar interbody fusion techniques.

In the current review, the authors aimed to educate readers about the MidLIF surgical technique, as well as surgical, clinical, radiographic, cost effectiveness, and biomechanical outcomes, when compared with both open and minimally invasive posterior lumbar interbody fusion techniques with pedicle screw fixation.

Readers will be able to utilize this information to determine how the MidLIF procedure compares as an alternative to traditional techniques.

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Factors associated with readmission after minimally invasive transforaminal lumbar interbody fusion

J Neurosurg Spine 38:681–687, 2023

The objective of this study was to identify factors that lead to a prolonged hospital stay or 30-day readmission after minimally invasive surgery (MIS) for transforaminal lumbar interbody fusion (TLIF) at a single institution.

METHODS Consecutive patients who underwent MIS TLIF from January 1, 2016, to March 31, 2018, were retrospectively analyzed. Demographic data, including age, sex, ethnicity, smoking status, and body mass index, were collected along with operative details, indications, affected spinal levels, estimated blood loss, and operative duration. The effects of these data were evaluated relative to the hospital length of stay (LOS) and 30-day readmission.

RESULTS The authors identified 174 consecutive patients who underwent MIS TLIF at 1 or 2 levels from a prospectively collected database. The mean (range) patient age was 64.1 (31–81) years, 97 were women (56%), and 77 were men (44%). Of 182 levels fused, 127 were done at L4–5 (70%), 32 at L3–4 (18%), 13 at L5–S1 (7%), and 10 at L2–3 (5%). Patients underwent 166 (95%) single-level procedures and 8 (5%) 2-level procedures. The mean (range) procedural duration, defined as the time from incision to closure, was 164.6 (90–529) minutes. The mean (range) LOS was 1.8 (0–8) days. Eleven patients (6%) were readmitted within 30 days; the most frequent causes were urinary retention, constipation, and persistent or contralateral symptoms. Seventeen patients had LOS greater than 3 days. Six of those patients (35%) were identified as widows, widowers, or divorced, and 5 of them lived alone. Six patients with prolonged LOS (35%) required placement in either skilled nursing or acute inpatient rehabilitation. Regression analyses showed living alone (p = 0.04) and diabetes (p = 0.04) as predictors of readmission. Regression analyses revealed female sex (p = 0.03), diabetes (p = 0.03), and multilevel surgery (p = 0.006) as predictors of LOS > 3 days.

CONCLUSIONS Urinary retention, constipation, and persistent radicular symptoms were the leading causes of readmission within 30 days of surgery in this series, which is distinct from data from the American College of Surgeons National Surgical Quality Improvement Program. The inability to discharge a patient home for social reasons led to prolonged inpatient hospital stays. Identifying these risk factors and proactively addressing them could lower readmission rates and decrease LOS among patients undergoing MIS TLIF.

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Rod fractures in thoracolumbar fusions to the sacrum/pelvis for adult symptomatic lumbar scoliosis

J Neurosurg Spine 38:217–229, 2023

Previous reports of rod fracture (RF) in adult spinal deformity are limited by heterogeneous cohorts, low follow-up rates, and relatively short follow-up durations. Since the majority of RFs present > 2 years after surgery, true occurrence and revision rates remain unclear. The objectives of this study were to better understand the risk factors for RF and assess its occurrence and revision rates following primary thoracolumbar fusions to the sacrum/pelvis for adult symptomatic lumbar scoliosis (ASLS) in a prospective series with long-term follow-up.

METHODS Patient records were obtained from the Adult Symptomatic Lumbar Scoliosis–1 (ASLS-1) database, an NIH-sponsored multicenter, prospective study. Inclusion criteria were as follows: patients aged 40–80 years undergoing primary surgeries for ASLS (Cobb angle ≥ 30° and Oswestry Disability Index ≥ 20 or Scoliosis Research Society-22r ≤ 4.0 in pain, function, and/or self-image) with instrumented fusion of ≥ 7 levels that included the sacrum/pelvis. Patients with and without RF were compared to assess risk factors for RF and revision surgery.

RESULTS Inclusion criteria were met by 160 patients (median age 62 years, IQR 55.7–67.9 years). At a median followup of 5.1 years (IQR 3.8–6.6 years), there were 92 RFs in 62 patients (38.8%). The median time to RF was 3.0 years (IQR 1.9–4.54 years), and 73% occurred > 2 years following surgery. Based on Kaplan-Meier analyses, estimated RF rates at 2, 4, 5, and 8 years after surgery were 11%, 24%, 35%, and 49%, respectively. Baseline radiographic, clinical, and demographic characteristics were similar between patients with and without RF. In Cox regression models, greater postoperative pelvic tilt (HR 1.895, 95% CI 1.196–3.002, p = 0.0065) and greater estimated blood loss (HR 1.02, 95% CI 1.005–1.036, p = 0.0088) were associated with increased risk of RF. Thirty-eight patients (61% of all RFs) underwent revision surgery. Bilateral RF was predictive of revision surgery (HR 3.52, 95% CI 1.8–6.9, p = 0.0002), while patients with unilateral nondisplaced RFs were less likely to require revision (HR 0.39, 95% CI 0.18–0.84, p = 0.016).

CONCLUSIONS This study provides what is to the authors’ knowledge the highest-quality data to date on RF rates following ASLS surgery. At a median follow-up of 5.1 years, 38.8% of patients had at least one RF. Estimated RF rates at 2, 4, 5, and 8 years after surgery were 11%, 24%, 35%, and 49%, respectively. Greater estimated blood loss and postoperative pelvic tilt were significant risk factors for RF. These findings emphasize the importance of long-term follow-up to realize the true prevalence and cumulative incidence of RF.

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The impact of cage positioning on lumbar lordosis and disc space restoration following minimally invasive lateral lumbar interbody fusion

Neurosurg Focus 54(1):E7, 2023

OBJECTIVE The objective of this study was to evaluate patient and surgical factors that predict increased overall lumbar lordosis (LL) and segmental lordosis correction following a minimally invasive lateral lumbar interbody fusion (LLIF) procedure.

METHODS A retrospective review was conducted of all patients who underwent one- or two-level LLIF. Preoperative, initial postoperative, and 6-month postoperative measurements of LL, segmental lordosis, anterior disc height, and posterior disc height were collected from standing lateral radiographs for each patient. Cage placement was measured utilizing the center point ratio (CPR) on immediate postoperative radiographs. Spearman correlations were used to assess associations between cage lordosis and radiographic parameters. Multivariate linear regression was performed to assess independent predictors of outcomes.

RESULTS A total of 106 levels in 78 unique patients were included. Most procedures involved fusion of one level (n = 50, 64.1%), most commonly L3–4 (46.2%). Despite no differences in baseline segmental lordosis, patients with anteriorly or centrally placed cages experienced the greatest segmental lordosis correction immediately (mean anterior 4.81° and central 4.46° vs posterior 2.47°, p = 0.0315) and at 6 months postoperatively, and patients with anteriorly placed cages had greater overall lordosis correction postoperatively (mean 6.30°, p = 0.0338). At the 6-month follow-up, patients with anteriorly placed cages experienced the greatest increase in anterior disc height (mean anterior 6.24 mm vs posterior 3.69 mm, p = 0.0122). Cages placed more posteriorly increased the change in posterior disc height postoperatively (mean posterior 4.91 mm vs anterior 1.80 mm, p = 0.0001) and at 6 months (mean posterior 4.18 mm vs anterior 2.06 mm, p = 0.0255). There were no correlations between cage lordotic angle and outcomes. On multivariate regression, anterior cage placement predicted greater 6-month improvement in segmental lordosis, while posterior placement predicted greater 6-month improvement in posterior disc height. Percutaneous screw placement, cage lordotic angle, and cage height did not independently predict any radiographic outcomes.

CONCLUSIONS LLIF procedures reliably improve LL and increase intervertebral disc space. Anterior cage placement improves the lordosis angle greater than posterior placement, which better corrects sagittal alignment, but there is still a significant improvement in lordosis even with a posteriorly placed cage. Posterior cage placement provides greater restoration in posterior disc space height, maximizing indirect decompression, but even the anteriorly placed cages provided indirect decompression. Cage parameters including cage height, lordosis angle, and material do not impact radiographic improvement.

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Unilateral approach with two‑cage insertion for full endoscopic transforaminal lumbar interbody fusion: technical report

Acta Neurochirurgica (2022) 164:1521–1527

The advantages of performing a transforaminal lumbar interbody fusion (TLIF) with two cages rather than a single cage include a larger cage-bone contact area and higher interbody stability.

Methods A customized cage guide is docked in the disc space created after a total facet resection. The first cage is inserted deeply into the contralateral disc space. The second cage is then inserted using the cage guide device while protecting the exiting and traversing nerve roots.

Conclusion We successfully inserted two cages from unilateral side during full endoscopic TLIF. This technique is recommended for L4–L5 and L5–S1 levels.

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Lumbar decompression surgery for cauda equina syndrome — comparison of complication rates between daytime and overnight operating

Acta Neurochirurgica (2022) 164:1203–1208

Purpose To investigate the incidence of complications from lumbar decompression ± discectomy surgery for cauda equina syndrome (CES), assessing whether time of day is associated with a change in the incidence of complications.

Methods Electronic clinical and operative notes for all lumbar decompression operations undertaken at our institution for CES over a 2-year time period were retrospectively reviewed. “Overnight” surgery was defined as any surgery occurring between 18:00 and 08:00 on any day. Clinicopathological characteristics, surgical technique, and peri/post-operative complications were recorded. Multivariable logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals.

Results A total of 81 lumbar decompression operations were performed in the 2-year period and analysed. A total of 29 (36%) operations occurred overnight. Complete CES (CESR) was seen in 13 cases (16%) in total, 7 of whom underwent surgery during the day. Exactly 27 complications occurred in 24 (30%) patients. The most frequently occurring complication was a dural tear (n = 21, 26%), followed by post-operative haematoma, infection, and residual disc. Complication rates in the CESR cohort (54%) were significantly greater than in the CES incomplete (CESI) cohort (25%) (p = 0.04). On multivariable analysis, overnight surgery was independently associated with a significantly increased complication rate (OR 2.83, CI 1.02–7.89).

Conclusions Lumbar decompressions performed overnight for CES were more than twice as likely to suffer a complication, in comparison to those performed within daytime hours. Our study suggests that out-of-hours operating, particularly at night, must be clinically justified and should not be influenced by day-time operating capacity.

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Decompression alone versus decompression and instrumented fusion for the treatment of isthmic spondylolisthesis: a randomized controlled trial

J Neurosurg Spine 35:687–697, 2021

The most advocated surgical technique to treat symptoms of isthmic spondylolisthesis is decompression with instrumented fusion. A less-invasive classical approach has also been reported, which consists of decompression only. In this study the authors compared the clinical outcomes of decompression only with those of decompression with instrumented fusion in patients with isthmic spondylolisthesis.

METHODS Eighty-four patients with lumbar radiculopathy or neurogenic claudication secondary to low-grade isthmic spondylolisthesis were randomly assigned to decompression only (n = 43) or decompression with instrumented fusion (n = 41). Primary outcome parameters were scores on the Roland Disability Questionnaire (RDQ), separate visual analog scales (VASs) for back pain and leg pain, and patient report of perceived recovery at 12-week and 2-year follow-ups. The proportion of reoperations was scored as a secondary outcome measure. Repeated measures ANOVA according to the intention-to-treat principle was performed.

RESULTS Decompression alone did not show superiority in terms of disability scores at 12-week follow-up (p = 0.32, 95% CI −4.02 to 1.34), nor in any other outcome measure. At 2-year follow-up, RDQ disability scores improved more in the fusion group (10.3, 95% CI 3.9–8.2, vs 6.0, 95% CI 8.2–12.4; p = 0.006, 95% CI −7.3 to −1.3). Likewise, back pain decreased more in the fusion group (difference: −18.3 mm, CI −32.1 to −4.4, p = 0.01) on a 100-mm VAS scale, and a higher proportion of patients perceived recovery as showing “good results” (44% vs 74%, p = 0.01). Cumulative probabilities for reoperation were 47% in the decompression and 13% in the fusion group (p < 0.001) at the 2-year follow-up.

CONCLUSIONS In patients with isthmic spondylolisthesis, decompression with instrumented fusion resulted in comparable short-term results, significantly better long-term outcomes, and fewer reoperations than decompression alone. Decompression with instrumented fusion is a superior surgical technique that should in general be offered as a first treatment option for isthmic spondylolisthesis, but not for degenerative spondylolisthesis, which has a different etiology. Clinical trial registration number: NTR1300 (Netherlands Trial Register)

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