Pennington, Zach

BACKGROUND AND OBJECTIVES: Transforaminal lumbar interbody fusion (TLIF) allows for direct and indirect decompression and segmental lordosis in sagittal plane correction. This study compares the effectiveness of “Bullet” type and “Banana” type devices for sagittal plane correction. METHODS: Patients who underwent 1-level or 2-level TLIF for degenerative pathology at a single tertiary care center were identified. Details were extracted on demographics, interbody dimensions, and preoperative and postoperative lumbopelvic parameters from upright radiographs. Cages were categorized as “Bullet” or “Banana” type based on morphology and manufacturer description of optimal position. Univariable comparisons between levels treated with “Bullet” and “Banana” type interbodies were performed. Multivariable linear regression was performed to identify independent predictors of postoperative segmental lordosis and change in segmental lordosis. RESULTS: One hundred and ninety eight unique patients (median 66.6 years; [IQR 59.5, 73.7]; 56.6% female) were included with 241 levels treated, of which 114 (52.7%) were treated with “Banana” type interbodies and 127 (47.3%) with “Bullet” type. “Banana” type interbodies afforded both greater postoperative segmental lordosis (8.1 [6.2, 10.7] vs 7.5 [5.2, 9.6]; P = .048) and greater increase in segmental lordosis (3.3 [0.7, 7.0] vs 2.3 [0.1, 4.2]; P = .015). On multivariable linear regression, only preoperative segmental lordosis (β = 0.322 per degree; [0.244, 0.399]; P < .001), implant listed lordosis (β = 0.146 per degree; 95% CI [0.048, 0.244]; P = .004), preoperative pelvic incidence (0.072 per degree; [0.034, 0.111]; P < .001), and use of bilateral TLIF windows (β = 3.133; [1.213, 5.053]; P = .001) were predictive of postoperative segmental lordosis. CONCLUSION: The present analysis suggests that baseline lumbopelvic anatomy, interbody lordosis, and the use of bilateral TLIF windows are the most important predictors of postoperative segmental lordosis. Use of “Banana” vs “Bullet” type interbodies was not predictive of segmental lordosis achieved on immediate postoperative upright radiographs. Further work is merited to determine whether the 2 interbody types demonstrate differences regarding subsidence risk or maintenance of correction.

Study Design Retrospective Cohort. Objectives Craniovertebral instability can arise from various congenital or acquired conditions, but definitive management often requires craniocervical fusion. This study evaluates whether postoperative clivo-axial angle (CXA) can predict distal junctional failure in patients undergoing craniocervical fusion. While postoperative alignment of the head and cervical spine can be quantified via the CXA, it is unclear whether the CXA can predict distal junctional failure. Methods All patients undergoing craniocervical decompression and fusion (CCF) for craniovertebral instability between 2012 and 2023 at a single institution were identified. Patients experiencing adjacent segment disease (ASD) were identified and compared to those without said pathology based on CXA, Grabb-Oakes line (pBC2), and the presence of cervical kyphosis, cervical disc degeneration, or subluxation on pre- and postoperative imaging. Statistical analysis included Shapiro-Wilk tests for normality, followed by independent t-tests or Mann-Whitney U tests with FDR adjusted P values as appropriate, and univariable logistic regression. Results 71 patients were included, of whom ten (14.3%) developed distal junctional kyphosis and 3 (4.3%) developed cervical spondylolisthesis. The median postoperative CXA was significantly lower in non-ASD patients (144° [IQR: 140-148°] vs 158° [IQR: 153-162°]; P < .001) and logistic regression showed that each 10° degree increase in CXA was associated with a 6.7-fold higher odds of ASD. Conclusions We found craniocervical alignment, as assessed by CXA, independently predicted distal junctional disease in patients undergoing craniocervical fusion, possibly due to low preoperative CXA in these patients. Large increases in CXA may contribute to postoperative instrumentation failure.

Background/Objectives: Both poor bone quality and paraspinal sarcopenia have been suggested as risk factors for proximal junctional kyphosis (PJK) at the upper instrumented vertebra (UIV) following long-segment thoracolumbar fusion. Methods: Adults ≥50 with a T1-6 UIV were identified, and data were gathered on pre- and postoperative spinopelvic parameters, bone quality (using Hounsfield units and vertebral bone quality score), and paraspinal cross-sectional area at L3 and the UIV. PJK was defined by a ≥10° increase in the proximal junctional angle. Cox regressions were performed to identify PJK risk factors; PJK was subdivided into types 1–3 based on the Yagi–Boachie classification. Results: In total, 15/76 patients (median age 66; 72.4% female) experienced PJK; 10 experienced type 1, 4 experienced type 2, and one experienced type 3. Univariable Cox regression showed that PJK was negatively correlated with total paraspinal muscle CSA at the UIV (HR 0.74/100 mm2; 95% CI [0.57, 0.6]; p = 0.02). Lower total paraspinal CSA at L3 (HR 0.94/100 mm2; p = 0.07) and higher postoperative global tilt (HR 1.03; p = 0.09) also trended toward significance. Similarly, type 1 PJK was predicted by smaller total paraspinal CSA at the UIV (HR 0.64/100 mm2; [0.45, 0.92]; p = 0.02). Paraspinal CSA was not predictive of type 2 PJK, but lower HU at the UIV and UIV + 1 trended toward significance (HR 0.98/unit; p = 0.16). A comparison of type 1 and 2 PJK showed a higher average of paraspinal CSA and a lower average of HU at the UIV. Conclusions: Global alignment and paraspinal sarcopenia were most predictive of PJK, though paraspinal sarcopenia was only predictive of type 1. Type 2 may be better predicted by bone quality.

OBJECTIVE Hounsfield units (HUs) may better predict biomechanical complications of instrumented fusion than conventional bone quality measures. Typically, noncontrast axial slices are used. This study aims to address the influence of reconstruction plane and contrast administration on measured HUs in patients undergoing lumbar spine imaging. METHODS Patients without prior spine surgery, infection, or tumor were identified for 3 groups: 1) 150 patients with high-resolution noncontrast lumbar CT, 2) 109 patients with noncontrast and contrast-enhanced lumbar CT, and 3) 100 patients with noncontrast lumbar CT and lumbar CT myelograms. Noncontrast HU measures in group 1 were compared between axial, sagittal, and coronal reconstructions. HU measures for groups 2 and 3 were compared on axial slice averages. HU measures between groups were compared using the Wilcoxon signed-rank test to investigate the presence of a statistically significant difference between groups (α = 0.05). Linear regression was also used to determine the degree of correlation between HU measures on noncontrast axial CT slices and HU measures on other sequences. RESULTS The mean patient age was 58.8 ± 15.9 years for group 1 (54.0% male), 65.5 ± 15.9 years for group 2 (61.5% male), and 65.2 ± 14.2 years (53.5% male) for group 3. Comparison of HU measures in group 1 showed significant differences across measurement modalities with the exception of axial average versus coronal average measures (p = 0.257) and sagittal average versus midsagittal measures (p = 0.726). There were significant differences in average axial HUs for each vertebral body between contrast and noncontrast lumbar CT and between CT myelography and noncontrast CT. Linear regression analysis demonstrated an extremely high correlation between measures for all methodologies (r2 = 0.950–0.986, all p < 0.001), and between contrast-enhanced and noncontrast studies (r2 = 0.870, p < 0.001). Measurements on CT myelography were significantly correlated with those in noncontrast studies, although to a lesser degree (r2 = 0.745, p < 0.001). CONCLUSIONS HU measures on noncontrast CT appear similar across multiple different planes, suggesting that a simpler methodology such as single-slice measurement on midsagittal reconstruction may allow for more rapid assessment of underlying bone quality. Consistent with prior work, contrast-enhanced CT sequences appear to reliably mirror underlying bone quality, although CT myelogram measures may vary in a more unpredictable way that precludes their use to interpret underlying bone quality. HU measures on contrast-enhanced studies are on average greater, suggesting the need for higher cutoff values.

Study Design: A meta-analysis approach to a systematic review. Objective: Perform a systematic review to identify all reports directly comparing outcomes of lateral lumbar interbody fusion (LLIF) using static versus expandable interbody cages. Specifically focusing on periprocedural complications, intraoperative morbidity, and fusion outcomes. Summary of Background Data: Minimally invasive surgical techniques, particularly LLIF, have gained popularity for their potential to reduce muscle and soft tissue dissection, leading to faster postoperative recovery. LLIF has been associated with fewer complications compared with open posterior approaches. The introduction of expandable lumbar interbody devices aims to further reduce surgical difficulty and potential complications. However, concerns include a small graft window due to the expansion mechanism and higher costs. Methods: The Web of Science, Scopus, and PubMed databases were systematically queried in accordance with PRISMA guidelines to identify articles comparing outcomes following LLIF using static and expandable interbodies. The Newcastle-Ottawa Scale (NOS) was employed to assess the risk of bias (ROB) in the selected studies. Extracted data underwent effect-size meta-analysis with the PyMARE library, using P<0.05 to define statistical significance. Results: Of the 77 identified articles, 4 studies comprising 283 patients (mean age: 67.1 y, 55.8% female) met the inclusion and exclusion criteria. A total of 150 patients (53%) were treated with static interbodies compared with 133 (47%) receiving expandable interbodies. The groups did not differ significantly with respect to operative time (P=0.59), blood loss (P=0.89), length of stay (P=0.78), subsidence (P=0.49), 24-month mean disc height (P=0.11), 24-month mean ODI (P=0.58), or 24-month mean visual analog scale (VAS) back pain (P=0.81). The expandable group saw a trend toward improved fusion rates (97% vs. 92%, P=0.06). Conclusions: The present meta-analysis suggests the use of expandable (vs. static) interbodies in LLIF surgery may result in similar surgical morbidity, subsidence, and decompression. Further prospective comparative studies are merited to validate these results.

Summary of Background Data: Although pseudoangina is most commonly caused by cervical disc herniation, several cases have been described where thoracic herniation produced symptoms of pseudoangina. If thoracic herniation can produce angina-like pain, then it is important to consider whether pathology of the thoracolumbar spine, in general, can trigger false pain syndromes distinct from pseudoangina. Objective: We seek to provide the most comprehensive study regarding the diagnosis and treatment of spinal conditions causing false pain syndromes. Study Design: Systematic review of the current literature using PRISMA 2020 recommendations. Methods: We queried the literature and systematically selected relevant studies according to PRISMA guidelines. Results: Across 22 selected studies, the sample size was 30 patients, and a total of 26 met the criteria for statistical analysis. Seven (26.9%) of these patients presented with a chief complaint of pseudoangina resulting from thoracic disc herniation. 73.1% (19/26) of patients exhibited pain mimicking visceral origin. Overall, 13/19 (68.4%) patients exhibited thoracic spine disease only and 4/19 (21.1%) patients were affected at lumbar levels only, while 2 (10.5%) patients exhibited thoracolumbar herniation. Presentations included abdominal pain (11/19) mimicking appendicitis or pancreatitis, flank pain mimicking renal colic (8/19), and 2 cases of scrotal pain/orchalgia. Symptom durations ranged from acute (<24 h) to 7 years. Treatments were reported for 18/19 patients and all treated patients reported alleviated pain. Seven out of 18 patients were managed conservatively while 11/18 were treated surgically. Misdiagnosis resulted in unnecessary surgery (pancreaticojejunostomy) or other invasive procedures. Conclusions: In spinal disorders manifesting with atypical pain syndromes, delay in proper diagnosis and unnecessary treatments can, unfortunately, cause prolonged patient suffering and increased cost of health care. As a result, some have proposed that spinal screening should be incorporated into clinical examinations involving false pain syndromes.

Study Design Survey study. Objectives The purpose of this study was to characterize the utility of 3D printed patient specific anatomic models for the planning of complex primary spine tumor surgeries. Methods A survey of individual members of an international study group of spinal oncology surgeons was performed. Participants were provided a clinical vignette, pathologic diagnosis, and pre-operative imaging for three primary spinal oncology cases. Study participants provided a free text surgical plan for resection and were then presented an associated 3D printed model for each case and asked to re-evaluate their surgical plan. Results Ten spinal oncology surgeons participated in the study, representing nine institutions across five countries. Four of the surgeons (40%) made significant changes to their surgical plan after reviewing the 3D models, including sacrifice of an additional nerve root to obtain negative margins, sparing an SI joint that was originally planned for inclusion in the en bloc resection, adjusting the location of osteotomy cuts, changes to the number of surgical stages and/or staging order, and preservation of neurology that was originally planned for sacrifice. The overall impression of the 3D models was positive, with 90% of the participants stating they found the 3D model useful in developing a surgical plan. Conclusions Surgical planning for resection of primary spinal column tumors is challenging and time intensive. 3D printed patient specific surgical models may be an additional tool that can augment surgical planning and execution by improving the chance of accomplishing surgical resection goals and minimizing morbidity.

Study Design Retrospective cohort study. Objective The impact of paraspinal sarcopenia following fusions that extend to the upper thoracic spine remain unknown. The purpose of the present study was to assess the impact of sarcopenia on the development of PJK and PJF following spine fusion surgery from the upper thoracic spine to the pelvis. Methods We performed a retrospective review of patients who underwent spine fusion surgery that extended caudally to the pelvis and terminated cranially between T1-6. The cohort was divided into 2 groups: (1) patients without PJK or PJF and (2) patients with PJK and/or PJF. Univariate and multivariate analyses were performed to determine risk factors for the development of proximal junctional complications. Results We identified 81 patients for inclusion in this study. Mean HU at the UIV was 186.1 ± 47.5 in the cohort of patients without PJK or PJF, which was substantially higher than values recorded in the PJK/PJF subgroup (142.4 ± 40.2) ( P < 0.001). Severe multifidus sarcopenia was identified at a higher rate in the subgroup of patients who developed proximal junction pathology (66.7%) than in the subgroup of patients who developed neither PJK nor PJF (7.4%; P < 0.001). Multivariate analysis demonstrated both low HU at the UIV and moderate-severe multifidus sarcopenia to be risk factors for the development of PJK and PJF. Conclusions Severe paraspinal sarcopenia and diminished bone density at the UIV impart an increased risk of developing PJK and PJF in following thoracolumbar fusions from the upper thoracic spine to the pelvis.