Alexander M. Lopez

Alexander M. Lopez

*This is an algorithmically generated author record based on publicly available information.

Current Organizations / Institutes

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Previous Organizations / Institutes

The organizations / institutes from the scholar's other articles in the past ten years


Alexander M. Lopez has a total of 77 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Top Cited Papers
    Open Access

    A Systematic Review of Treatment Guidelines for Lumbar Disc Herniation

    by Haiyue Jin, Alexander M. Lopez, Flor Garza Romero, Ryan Hoang, Ashish Ramesh, Hansen C. Bow

    Various treatments have been developed for treating herniated lumbar discs (HLD), which have been examined by professional associations when composing clinical guidelines that provide structured approaches to treating HLD. This paper aims to gather recent guidelines and summarize their conclusions on nonsurgical and surgical treatment options. PubMed, Web of Science, Scopus, Guidelines International Network, Turning Research into Practice databases, and websites of medical societies were searched for clinical guidelines of HLD. Full-text guidelines published by a professional association in English relevant to HLD were included. Comparisons among guidelines were made based on the treatments evaluated, and recommendation grades were recorded when provided by the guidelines. A total of 12 guidelines were included, with 4 by non-United States (US) or international associations, 3 by US pain societies, 2 by surgical societies, 2 by government agencies, and 1 by a multidisciplinary medical society. Treatments assessed included surgical, invasive nonsurgical, and noninvasive nonsurgical interventions. Three guidelines did not include surgical treatments, and 2 guidelines did not include nonsurgical therapies. Recommendation criteria varied among guidelines due to differences in the intended audience. HLD can be treated with various modalities with specific therapies offering better pain relief. Despite inconsistency in the recommendation grades of most treatments, established surgical techniques and epidural injections were reported with higher confidence in recommendation estimates, while inadequate supporting evidence was shown for noninvasive therapies except cognitive behavioral therapy. Future studies could incorporate and comment on some of the newer methods of treating HLD.


  • Open Access

    Comparison of CT-Guided needle biopsy versus percutaneous endoscopic debridement and drainage in pathogen identification and pain outcomes for spondylodiscitis patients: A systematic review and literature review

    by Nischal Acharya, Joshua S. Kurtz, Kylie T. Callan, Gabrielle E.A. Hovis, Scarlett R.K. Mar, Alexander Lopez, Alvin Y. Chan, Hao-Hua Wu, Sohaib Z. Hashmi, Nitin N. Bhatia, et al.


  • Open Access

    Outcome of Percutaneous Endoscopic Lumbar Discectomy in Relation to the Surgeon’s Experience: Propensity Score Matching

    by Seong Son, Michael Y. Oh, Han Byeol Park, Alexander M. Lopez

    Percutaneous endoscopic lumbar discectomy (PELD) presents a challenging learning curve, and the correlation between surgeon experience and clinical outcomes remains contentious. This retrospective study aimed to compare the outcomes of PELD performed by a single surgeon at beginner and experienced stages. Propensity score matching selected 150 patients (75 per group) with a minimum 3-year follow-up. Clinical and radiological outcomes, perioperative complications, and adverse events were assessed. Baseline characteristics, pain improvement, patient satisfaction, and radiological outcomes did not differ between the groups. However, operation time was longer in the beginner group than in the experienced group (57.5 min [IQR, 50.0–70.0] versus 50.0 min [IQR, 45.0–55.0], p < 0.001). The beginner group had higher perioperative complication rates (eight patients [10.7%] versus one patient [1.3%], with a hazard ratio of 8.836 [95% CI, 1.077–72.514], p = 0.034) and lower 3-year survival without adverse events (19 patients [25.3%] in the beginner group and 10 patients [13.3%] in the experienced group, p = 0.045). Our findings indicate that the clinical outcomes were more favorable in patients operated on at the experienced stage compared to those treated at the beginner stage.


  • Open Access

    What is the Philosophy of Neurosurgery? Systematic Review and Defining the Discipline

    by Rajeev R. Dutta, Alexander Lopez, Frank P.K. Hsu, Michelle Paff


  • Open Access

    Endoscopic Anterior Lumbar Interbody Fusion: Systematic Review and Meta-Analysis

    by Nolan J. Brown, Zach Pennington, Cathleen C. Kuo, Alexander M. Lopez, Bryce Picton, Sean Solomon, Oanh T. Nguyen, Chenyi Yang, Evelyne K. Tantry, Hania Shahin, et al.

    Laparoscopic anterior lumbar interbody fusion (L-ALIF), which employs laparoscopic cameras to facilitate a less invasive approach, originally gained traction during the 1990s but has subsequently fallen out of favor. As the envelope for endoscopic approaches continues to be pushed, a recurrence of interest in laparoscopic and/or endoscopic anterior approaches seems possible. Therefore, evaluating the current evidence base in regard to this approach is of much clinical relevance. To this end, a systematic literature search was performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines using the following keywords: “(laparoscopic OR endoscopic) AND (anterior AND lumbar).” Out of the 441 articles retrieved, 22 were selected for quantitative analysis. The primary outcome of interest was the radiographic fusion rate. The secondary outcome was the incidence of perioperative complications. Meta-analysis was performed using RStudio’s “metafor” package. Of the 1,079 included patients (mean age, 41.8±2.9 years), 481 were males (44.6%). The most common indication for L-ALIF surgery was degenerative disk disease (reported by 18 studies, 81.8%). The mean follow-up duration was 18.8±11.2 months (range, 6–43 months). The pooled fusion rate was 78.9% (95% confidence interval [CI], 68.9–90.4). Complications occurred in 19.2% (95% CI, 13.4–27.4) of L-ALIF cases. Additionally, 7.2% (95% CI, 4.6–11.4) of patients required conversion from L-ALIF to open surgery. Although L-ALIF does not appear to be supported by studies available in the literature, it is important to consider the context from which these results have been obtained. Even if these results are taken at face value, the failure of endoscopy to have a role in the ALIF approach does not mean that it should not be incorporated in posterior approaches.

  • Open Access

    External Validation of the Global Alignment and Proportion Score as Prognostic Tool for Corrective Surgery in Adult Spinal Deformity: A Systematic Review and Meta-Analysis

    by Julian L. Gendreau, Andrew Nguyen, Nolan J. Brown, Zach Pennington, Alexander M. Lopez, Neal Patel, Sachiv Chakravarti, Cathleen Kuo, Gaston Camino-Willhuber, Stephen Albano, et al.


  • Resident Training in Spine Surgery: A Systematic Review of Simulation-Based Educational Models

    by Ghassan J. Farah, James L. Rogers, Alexander M. Lopez, Nolan J. Brown, Zach Pennington, Cathleen Kuo, Justin Gold, Nicholas E. Bui, Stefan W. Koester, Julian L. Gendreau, et al.


  • Enhancement of medical student perception of surgical specialization with peer-assisted laparoscopic simulation: a pilot study

    by Jordan J. Baechle, Alexander M. Lopez, Jyotsna Thota, Mitchell F. Bowers, Paula Marincola Smith, Regina S. Offodile


  • Open Access

    Subthalamic Nucleus Subregion Stimulation Modulates Inhibitory Control

    by Nelleke C van Wouwe, Joseph S Neimat, Wery P M van Den Wildenberg, Shelby B Hughes, Alexander M Lopez, Fenna T Phibbs, Jeffrey D Schall, William J Rodriguez, Elise B Bradley, Benoit M Dawant, et al.

    Patients with Parkinson’s disease (PD) often experience reductions in the proficiency to inhibit actions. The motor symptoms of PD can be effectively treated with deep brain stimulation (DBS) of the subthalamic nucleus (STN), a key structure in the frontal–striatal network that may be directly involved in regulating inhibitory control. However, the precise role of the STN in stopping control is unclear. The STN consists of functional subterritories linked to dissociable cortical networks, although the boundaries of the subregions are still under debate. We investigated whether stimulating the dorsal and ventral subregions of the STN would show dissociable effects on ability to stop. We studied 12 PD patients with STN DBS. Patients with two adjacent contacts positioned within the bounds of the dorsal and ventral STN completed two testing sessions (OFF medication) with low amplitude stimulation (0.4 mA) at either the dorsal or ventral contacts bilaterally, while performing the stop task. Ventral, but not dorsal, DBS improved stopping latencies. Go reactions were similar between dorsal and ventral DBS STN. Stimulation in the ventral, but not dorsal, subregion of the STN improved stopping speed, confirming the involvement of the STN in stopping control and supporting the STN functional subregions.


  • Structural Correlates of the Sensorimotor Cerebellum in Parkinson's Disease and Essential Tremor

    by Alexander M. Lopez, Paula Trujillo, Adreanna B. Hernandez, Ya‐Chen Lin, Hakmook Kang, Bennett A. Landman, Dario J. Englot, Benoit M. Dawant, Peter E. Konrad, Daniel O. Claassen

    Background: Parkinson's disease (PD) and essential tremor (ET) are commonly encountered movement disorders. Pathophysiologic processes that localize to the cerebellum are described in both. There are limited studies investigating cerebellar structural changes in these conditions, largely because of inherent challenges in the efficiency of segmentation.Methods: We applied a novel multiatlas cerebellar segmentation method to T1‐weighted images in 282 PD and 111 essential tremor patients to define 26 cerebellar lobule volumes. The severity of postural and resting tremor in both populations and gait and postural instability in PD patients were defined using subscores of the UPDRS and Washington Heights‐Inwood Genetic Study motor scales. These clinical measurements were related to lobule volume size. Multiple comparisons were controlled using a false discovery rate method.Results: Group differences were identified between ET and PD patients, with reductions in deep cerebellar nucleus volume in ET versus reduced lobule VI volume in PD. In ET patients, lobule VIII was negatively correlated with the severity of postural tremor. In PD patients, lobule IV was positively correlated with resting tremor and total tremor severity. We observed differences in cerebellar structure that localized to sensorimotor lobules of the cerebellum. Lobule volumes appeared to differentially relate to clinical symptoms, suggesting important clinicopathologic distinctions between these conditions. These results emphasize the role of the cerebellum in tremor symptoms and should foster future clinical and pathologic investigations of the sensorimotor lobules of the cerebellum. © 2020 International Parkinson and Movement Disorder Society