Publications by authors named "Jorge Rasmussen"

19 Publications

  • Page 1 of 1

Relationship between the posterior septal artery and the upper edge of the choana.

Surg Radiol Anat 2021 Mar 10. Epub 2021 Mar 10.

Neurosurgery Department, Hospital Italiano de Buenos Aires-Argentina, Tte. Gral. Juan D. Perón 4190, CABA, CP C1199ABD, Buenos Aires, Argentina.

Background: The pedicled nasoseptal flap has been a key element in advancing the endoscopic transnasal approach (ETA) for the treatment of skull base lesions from the anterior cranial fossa to the occipitocervical junction. To preserve vascular supply, an anatomical knowledge of the location of the posterior septal artery (PSA) is essential. The objective of this work is to establish the relationship between PSA and the superior edge of the choana to define a safety margin during the opening of the sphenoidal rostrum preserving PSA.

Methods: One hundred and eighty angiotomographies of the brain were assessed. The sphenopalatine artery (SPA) was evaluated in the pterygopalatine fossa and PSA at its entrance into the nasal cavity and on the sphenoidal rostrum.

Results: PSA was found in all 3 tomographic planes (axial, coronal and sagittal) in 100 patients (200 PSAs). Thirty-five were male and 65 were females. Average age was 62 years with a range of 19-90 years. Total average distance between PSA and the superior edge of the choana was 8.5 mm with a range of 2.5-18 (12.45 90th percentile).

Conclusion: Although the distance between the choanal edge and PSA is 8.5 mm on average, due to its variability, a distance of at least 12.45 mm for the opening of the sphenoidal sinus in the ETA approach should be considered as a safety margin.
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http://dx.doi.org/10.1007/s00276-021-02732-7DOI Listing
March 2021

Surgical Indication Optimization of Brain Metastases Based on the Evolutionary Analysis of Karnofsky Performance Status.

J Neurol Surg A Cent Eur Neurosurg 2021 May 24;82(3):211-217. Epub 2021 Jan 24.

Department of Neurosurgery, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina.

Background And Objective:  Surgical resection of brain metastases (BM) offers the highest rates of local control and survival; however, it is reserved for patients with good functional status. In particular, the presence of BM tends to oversize the detriment of the overall functional status, causing neurologic deterioration, potentially reversible following symptomatic pharmacological treatment. Thus, a timely indication of surgical resection may be dismissed. We propose to identify and quantify these variations in the functional status of patients with symptomatic BM to optimize the indication of surgical resection.

Patients And Methods:  Historic, retrospective cohort analysis of adult patients undergoing BM microsurgical resection, consecutively from January 2012 to May 2016, was conducted. The Karnofsky performance status (KPS) variation was recorded according to the symptomatic evolution of each patient at specific moments of the diagnostic-therapeutic algorithm. Finally, survival curves were delineated for the main identified factors.

Results:  One hundred and nineteen resection surgeries were performed. The median overall survival was 243 days, while on average it was 305.7 (95% confidence interval [CI]: 250.6-360.9) days. The indication of surgical resection of 10% of the symptomatic patients in our series (7.5% of overall) could have been initially rejected due to pharmacologically reversible neurologic impairment. Survival curves showed statistically significant differences when KPS was stratified following pharmacological symptomatic treatment ( < 0.0001), unlike when they were estimated at the time of BM diagnosis ( = 0.1128).

Conclusion:  The preoperative determination of the functional status by KPS as an evolutive parameter after the nononcologic symptomatic pharmacological treatment allowed us to optimize the surgical indication of patients with symptomatic BM.
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http://dx.doi.org/10.1055/s-0040-1714410DOI Listing
May 2021

Extensive Periprosthetic Metallosis Associated to Osteolysis and Spinal Instrumentation Failure: Case Report and Literature Review.

Spine (Phila Pa 1976) 2021 May;46(9):E551-E558

Spine Unit, Neurosurgery Department, Hospital Español de Mendoza, Mendoza, Argentina.

Study Design: Case-report and literature review.

Objective: To depict main features of a potentially deleterious postoperative spinal fixation complication.

Summary Of Background Data: Tisular deposit of metal particles from prosthetic systems-metallosis-is an uncommon complication of spinal fixation surgery. Manifestations as chronic postoperative pain, instrumentation failure, infection, or neurological impairment can be developed, but metallosis often appears as an unexpected intraoperative finding.

Methods: A 70-year-old female underwent several spinal fixation procedures due to progressive degenerative adult scoliosis, who developed instrumentation failure. Unexpected metallosis was evidenced extensively surrounding the dislodged construct due to vertebral osteolysis. Instrumentation replacement and debridement of metallotic tissue was performed. We also conduct a literature review for the terms "spinal metallosis" and "spinal corrosion" on the PubMed/MEDLINE database. Previous publications depicting black/dark staining, discoloration and/or fibrotic tissue, as well as histopathological metal particle deposits, or merely metallosis, were reviewed. Articles reporting individual cases or case-series/cohorts with patient-discriminated findings were included.

Results: The histopathological analysis of our patient revealed dense fibroconnective tissue with black metallic pigment associated. She evolved with great pain relief in the immediately postoperative period. The patient achieved pain-free standing with significant pharmacotherapy reduction and independent ambulation. The literature search retrieved 26 articles for "spinal metallosis" and 116 for "spinal corrosion"; 16 articles met selection criteria. Approximately 60% of the reported cases accounted for patients younger than 30 years old, mainly related to expandable fixation system (65%) for idiopathic scoliosis. Usually, the symptoms were correlated with abnormal radiological findings: instrumentation breakage, dislodgement, loosening, expandable systems fracture. All the reviewed patients evolved free of pain and neurologically recovered.

Conclusion: Instrumentation removal and metallosis debridement seems to be useful for symptomatic patients, but remains controversial on fixed asymptomatic patients. If solid fusion has not been achieved, extension, and reinforcement of the failed fixation could be required.Level of Evidence: 4.
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http://dx.doi.org/10.1097/BRS.0000000000003831DOI Listing
May 2021

A Classification for the Anterior Inferior Cerebellar Artery-Subarcuate Artery Complex Based on the Embryological Development.

J Neurol Surg B Skull Base 2020 Oct 21;81(5):536-545. Epub 2019 Jun 21.

Department of Neurosurgery, Italian Hospital of Buenos Aires, Buenos Aires, Argentina.

 To hierarchize the anterior inferior cerebellar artery (AICA)-subarcuate artery (SAA) complex's variations in the surgical field.  The AICA's "subarcuate loop" (SL) presents multiple variations, closely related to the SAA. AICA-SAA complex's variations may represent major issues in cerebellopontine angle (CPA) surgery. As the spectrum of configurations is originated during the development, a systematized classification was proposed based on the interaction between the petrosal bone and the AICA in the embryonic period.  The variations were defined as follow: Grade 0: free, purely cisternal AICA, unidentifiable or absent SAA; Grade 1: purely cisternal AICA, loose SL, SAA > 3 mm; Grade 2: AICA near the subarcuate fossa, pronounced SL, SAA <3 mm; Grade 3: "duralized" AICA, unidentifiable SAA, or included in the petromastoid canal (PMC); and Grade 4: intraosseous AICA, unidentifiable SAA, or included in the PMC. The classification was applied to a series of patients assessed by magnetic resonance constructive interference in steady state sequence. Surgical examples were also provided.  Eighty-four patients were evaluated, including 161 CPA. The proportions found in the gradation remained within the range of previous publications (Grade 0: 42.2%; Grade 1: 11.2%; Grade 2: 35.4%; Grade 3: 10.6%; and Grade 4: 0.6%). Moreover, the degrees of the classification were related to the complexity of the anatomical relationships and, therefore, to the difficulty of the maneuvers required to overcome them.  The proposed AICA-SAA complex classification allowed to distinguish and objectify pre- and intraoperatively the spectrum of variations, to thoroughly plan the required actions and instrumentation.
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http://dx.doi.org/10.1055/s-0039-1692474DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7591361PMC
October 2020

Effect of oxidized cellulose on human respiratory mucosa and submucosa and its implications for endoscopic skull-base approaches.

Int Forum Allergy Rhinol 2020 03 19;10(3):282-288. Epub 2019 Dec 19.

Department of Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, PA.

Background: Regenerated oxidized cellulose (ROC) sheets have gained popularity as an adjunct to a vascularized nasoseptal flap for closure of dural defects after endoscopic endonasal skull-base approaches (EESBS). However, evidence supporting its impact on the healing process is uncertain. This study was performed to evaluate the impact of ROC on the nasal mucosa and assess its effects on tissue pH, structure, and cell viability.

Methods: In 5 patients, a 1-cm piece of ROC gauze was placed on the surface of the middle turbinate before it was resected as part of a standard EESBS. Mucosa treated with ROC was separated from untreated mucosa and a histologic examination of structural changes in the respiratory epithelium was performed. To assess the effect of ROC on pH, increasing amounts of ROC were added to culture medium. Nasal fibroblasts viability was assessed in the presence of ROC before and after the pH was neutralized.

Results: Compared with unexposed controls, treated mucosa exhibited a higher incidence of cell necrosis and epithelial cell detachment. When added to Dulbecco's modified Eagle medium, ROC caused a dose-dependent decrease in pH of the medium. Only 1 ± 0.8% of cultured fibroblasts exposed to the ROC-induced acidic medium were alive, whereas 98.25 ± 0.5% of the cells were viable when the pH was neutralized (p < 0.001).

Conclusion: ROC applied in vivo to nasal mucosa induced epithelial necrosis likely by diminishing the medium pH, because pH neutralization prevents its effect. The ultimate effect of this material on the healing process is yet to be determined.
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http://dx.doi.org/10.1002/alr.22495DOI Listing
March 2020

[Minimally invasive resection of spinal synovial cysts: Technical note].

Surg Neurol Int 2019 15;10(Suppl 1):S12-S20. Epub 2019 Feb 15.

Departmento de Neurocirugía - Hospital Italiano de Buenos Aires, Argentina.

Objective: To present the treatment algorithm, surgical technique, and results of a series of patients with spinal synovial cysts operated with minimally invasive techniques (MIS).

Introduction: Spinal synovial cysts originate from the dilation and potential rupture of the synovial sheath of a facet joint. Surgical resection is considered the treatment of choice in symptomatic patients. The use of MIS techniques could reduce the disruption of the facet joint involved, reducing the risk of postoperative instability.

Materials And Methods: We retrospectively evaluated 21 patients with spinal synovial cysts operated by MIS approach and decompression. We analyzed the signs, symptoms, surgical time, hospital stay, evolution, and complications. The visual analog scale (VAS) was used to evaluate pain and the Weiner scale and the modified Macnab criteria to measure the patient's postoperative satisfaction.

Results: A total of 21 patients were surgically treated with MIS technique; 76.2% ( = 16) did not require arthrodesis, the remaining 23.8% ( = 5) were fused. We performed 13 (61.9%) contralateral hemilaminectomies, 7 ipsilateral hemilaminectomies (33.3%), and 1 laminectomy in S1-S2. The average follow-up was 26 months; surgical time was 150.33 ± 63.31 min, with a hospital stay of 2.5 ± 1.78 days. The VAS decreased from 8.3 preoperatively to 2.3 postoperatively. Sixteen patients reported excellent results, four good and one regular in the scale of Macnab. 95.2% of patients perceived that the procedure was very/quite successful according to the Weiner scale.

Conclusion: The minimally invasive approach is a safe and effective procedure for the complete resection of spinal synovial cysts. It provides excellent clinical-functional results by preserving muscles, ligaments, and joint facets.
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http://dx.doi.org/10.4103/sni.sni_416_18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6416767PMC
February 2019

[Usefulness of minimally invasive spine surgery for the management of thoracolumbar spinal metastases].

Surg Neurol Int 2019 15;10(Suppl 1):S1-S11. Epub 2019 Feb 15.

Departamento de Neurocirugía, Hospital Italiano de Buenos Aires, Peron, CABA, Argentina.

Objective: To describe the surgical results and evolution of patients who underwent minimally invasive spine surgery (MISS) for the treatment of thoracolumbar spinal metastases, using the NOMS (Neurological, Oncological, Mechanical, Systemic) assessment for the therapeutic decision.

Methods: Patients who underwent MISS technique for the treatment of thoracolumbar spinal metastases were prospectively enrolled at the Hospital Italiano de Buenos Aires, from June 2014 to June 2017. In all cases, the NOMS assessments were performed for therapeutic decision making. Surgical results were analyzed in terms of improvements in Karnofsky performance status, pain relief (VAS - visual analog scale), Frankel, blood loss, need for transfusions, complications, use of opioids and hospitalization length. A < 0.05 value was considered statistically significant.

Results: During the study period 26 patients were included, 13 of them were women. The average age was 57-year-old (27-83 years). Breast cancer was the most frequent primary tumor (27%). The main symptom was pain (96%), although 12 patients presented with myelopathy (46%). High-grade epidural spinal cord compression requiring decompression was observed in 17 cases (65%). According to the SINS (spinal instability neoplastic score), most lesions were potentially unstable or unstable (89%) requiring MISS stabilization. After surgery, pain relief (VAS) and neurological recovery (Frankel) improved significantly in the 77% and 67% of the cases, respectively, with low intraoperative blood loss and without any transfusions. Only one minor surgical complication was presented (4%). The average of hospital stay was 5.5 days.

Conclusion: In our series and using the NOMS as a therapeutic algorithm, MISS was effective for decompression and spinal stabilization, with a low rate of complications and rapid postoperative recovery.
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http://dx.doi.org/10.4103/sni.sni_288_18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6416751PMC
February 2019

Accuracy in Percutaneous Transpedicular Screws Placement Using Biplane Radioscopy: Systematic Review and Meta-Analysis.

Clin Spine Surg 2019 06;32(5):198-207

Department of Neurosurgery, Italian Hospital of Buenos Aires, Autonomous City of Buenos Aires, Argentina.

Study Design: Systematic review and descriptive data meta-analysis.

Objective: The objective of this study was to appropriately establish the accuracy in the percutaneous transpedicular screws (PTS) placement using biplane radioscopy (Rx-2D).

Summary Of Background Data: The Rx-2D is a widely-used technique for PTS as it is practical, ubiquitous, and cost-effective. However, the reported "acceptable" accuracy attained by this method is widely variable ranging between 76% and 100%.

Methods: A systematic review was conducted to screen publications about PTS placement using Rx-2D guidance. PubMed/MEDLINE database was consulted using the search term "percutaneous pedicle screw" from 1977 to 2017. Previous meta-analysis and reference lists of the selected articles were reviewed. Accuracy values were assessed fulfilling the proposed criteria. Observational data meta-analysis was performed. Cochran's Q test was used to determine heterogeneity among data extracted from the series, which was quantified by I test. P-values≤0.05 were considered statistically significant. The results were depicted by Forest plots. Funnel plots were outlined to visualize a possible bias of publication among the selected articles.

Results: In total, 27 articles were included in the analysis. Results of the accuracy were as follow, 91.5% (n=7993; 95% CI, 89.3%-93.6%) of the screws were placed purely intrapedicular, and 96.1% (n=8579; 95% CI, 94.0%-98.2%) when deviation from the pedicle was up to 2 mm.

Conclusions: This meta-analysis is the largest review of PTS placed with Rx-2D guidance reported up to date. We concluded that the procedure is a safe and reproducible technique. The key values obtained in this work set reliable references for both clinical and training outcome assessing.
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http://dx.doi.org/10.1097/BSD.0000000000000801DOI Listing
June 2019

Differential response of pineal microglia to surgical versus pharmacological stimuli.

J Comp Neurol 2018 10 24;526(15):2462-2481. Epub 2018 Sep 24.

Institute of Histology and Embryology of Mendoza (IHEM), National University of Cuyo, National Scientific and Technical Research Council (CONICET), Mendoza, Argentina.

Microglial cells are one of the interstitial elements of the pineal gland (PG). We recently reported the pattern of microglia colonization and activation, and microglia-Pax6 cell interactions during normal pineal ontogeny. Here, we describe the dynamics of microglia-Pax6 cell associations and interactions after surgical or pharmacological manipulation. In adult rats, the superior cervical ganglia (SCG) were exposed, and either bilaterally excised (SCGx) or decentralized (SCGd). In the SCGx PGs, the density of Iba1 microglia increased after surgery and returned to sham baseline levels 13 days later. Pineal microglia also responded to SCGd, a more subtle denervation. The number of clustered Iba1 /PCNA /ED1 microglia was higher 4 days after both surgeries compared to the sham-operated group. However, the number of Pax6 /PCNA cells and the percentage of Pax6 cells contacted by and/or phagocytosed by microglia increased significantly only after SCGx. Separate groups of rats were treated with either bacterial lipopolysaccharides (LPS) or doxycycline (DOX) to activate or inhibit pineal microglia, respectively. Peripheral LPS administration caused an increase in the number of clustered Iba1 /PCNA /ED1 microglial cells, and in the percentage of Pax6 cells associated with and/or engulfed by microglia. In the LPS-treated PGs, we also noted an increase in the number of PCNA cells that were Iba1 within the microglial cell clusters. The density of Pax6 cells did not change after LPS treatment. DOX administration did not influence the parameters analyzed. These data suggest that pineal microglia are highly receptive cells capable of rapidly responding in a differential manner to surgical and pharmacological stimuli.
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http://dx.doi.org/10.1002/cne.24505DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6196128PMC
October 2018

[Drilling of the subarcuate fossa to release the anterior inferior cerebellar artery in a surgery of a vestibular Schwannoma].

Surg Neurol Int 2018 13;9(Suppl 3):S66-S72. Epub 2018 Aug 13.

Servicio de Neurocirugía, Hospital Civil, Guadalajara, México.

Introduction: A retrosigmoid suboccipital approach is the route most commonly utilized to resect vestibular schwannomas (VS). However, the anterior inferior cerebellar artery (AICA) usually runs adjacent to internal auditory canal nerves, and its course may severely impede total tumor resection.

Case Report: A 38-year-old male patient presented with presumed grade T3B VS, diagnosed by magnetic resonance imaging (MRI). Surgery was performed using a retrosigmoid approach, during which the AICA was identified to be completely covered by dural and bone tissue. Further drilling in the subarcuate fossa was necessary to release the AICI, allowing for total gross resection of the VS. No neurological deficits were observed postoperatively.

Discussion: On rare occasions, the AICA has been described fixed to the dura and/or embedded within subarcuate fossal bone, thereby preventing removal of the intra-canalicular portion of the VS and, hence, total resection. However, AICA release adds to the risk of vascular injury.

Conclusion: Injury to the AICA may cause high morbidity in patients with a VS. Neurosurgeons must be able to recognize and deal with certain anatomical configurations that place patients at particularly high risk.
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http://dx.doi.org/10.4103/sni.sni_219_18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6108169PMC
August 2018

[Optical coherence tomography as a predictor of visual recovery in patients with pituitary macroadenomas].

Surg Neurol Int 2018 13;9(Suppl 3):S57-S65. Epub 2018 Aug 13.

Servicio de Neurocirugía, Hospital Italiano de Buenos Aires, Buenos Aires.

Background: With pituitary macroadenomas, there is a high incidence of visual loss from optic pathway compression. Surgical removal of the tumor usually prevents progression and allows visual recovery. Our objective was to evaluate if optical coherence tomography (OCT) predicts visual outcomes after surgical decompression.

Methods: Patients with pituitary macroadenomas were prospectively recruited between February 2015 and November 2016. We evaluated preoperative and postoperative visual acuity, automated perimetry, and OCT. We compared the results 6-12 weeks and 6-9 months after surgical removal of the tumor. Dependent and independent continuous variables were analyzed by Student's -test, linear regression analysis, and Pearson's correlation coefficients, considering < 0.05 as statistically significant.

Results: Visual acuity and visual field defects were much worse in patients with a thin preoperative retinal nerve fiber layer (RNFL). Both patients with normal RNFL thickness and patients with thin RNFL experienced significant improvement in postoperative visual perimetry 6-12 weeks after surgery. OCT values correlated inversely with pre- and postoperative visual fields, which means that, if the nerve was thicker, the visual field was better. Patients with a normal OCT had greater recovery because their preoperative perimetry values were better. The correlation between OCT values and visual field improvement was weak, suggesting that patients' visual fields improved after decompressive surgery independent of the nerve's thickness.

Conclusion: The computerized visual field continues to be the gold standard in the evaluation of patients with pituitary macroadenomas with optic pathway compression. Our results suggest that OCT might not be an accurate predictor of visual outcomes.
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http://dx.doi.org/10.4103/sni.sni_463_17DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6108170PMC
August 2018

Application of Fibrin Rich in Leukocytes and Platelets in the Reconstruction of Endoscopic Approaches to the Skull Base.

World Neurosurg 2018 Oct 30;118:32-41. Epub 2018 Jun 30.

Department of Neurosurgery, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina.

Background: The objective of this work is to report the feasibility and results of an institutional protocol for the application of an innovative biologically active hemoderivative autologous material, denominated leukocyte- and platelet-rich fibrin (L-PRF), in the reconstruction of endoscopic approaches to the sellar region.

Methods: L-PRF membranes were produced from centrifuged autologous venous blood. They were used for the reconstruction of transsphenoidal endoscopic approaches to the sellar region in 12 patients. The trophism of the mucosa was monitored during the first 30 days by means of fiberoptic endoscopic controls on the second and seventh postoperative days. Follow-up was performed to rule out complications up to 30 postoperatively days.

Results: The product obtained bore the characteristics of the original descriptions of L-PRF. Standardized preparation of L-PRF membranes promoted early regeneration of the sphenoid sinus mucosa to close endoscopic approaches to the sellar region. No complications within the first 30 postsurgical days were reported.

Conclusions: L-PRF membranes offer characteristics that are superior to other techniques and products, mainly because of their role as biological promoters of tissue regeneration, their low economic cost, and immediate availability. However, it would be necessary to confirm these results in studies involving more patients.
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http://dx.doi.org/10.1016/j.wneu.2018.06.180DOI Listing
October 2018

[Learning curve of minimally invasive pedicle screw placement].

Surg Neurol Int 2018 10;9(Suppl 2):S43-S49. Epub 2018 May 10.

Departamento de Neurocirugía, Hospital Italiano de Buenos Aires, Argentina.

Objective: The aim of this study was to estimate the learning curve needed for correct placement of minimally invasive percutaneous pedicle screws (PPS).

Introduction: PPS are the most common system used for instrumentation of spinal lesions that require stabilization.

Methods: We retrospectively assessed the insertion of 422 PPS (T5 to S1) in 75 patients operated between 2013-2016 under two-dimensional fluoroscopic guidance. The surgeon 1 always placed the PPS on the right side and the surgeon 2 on the left side. Screw positioning and pedicle rupture was determined with the Gertzbein tomographic classification. We compared the accuracy of PPS placement in our series with a reference rupture rate of 8.08%, value obtained from a meta-analysis.

Results: Of the 422 TTP, 395 were inserted into the pedicle without violation of its cortical wall (Grade 1 = 93.6%), 27 (6.4%) disrupted the pedicle, of which 3.8% were Grade 2, 1.65% Grade 3 and only 0.9% Grade 4. The Surgeon 1, presented an overall break rate of 6.6% reaching standard values of accuracy by placing 74 PPS, Surgeon 2 showed a disruption rate of 6.1%, reaching baseline values at 64 PPS; the difference between them was not statistically significant ( = 0.9009).

Conclusion: In our series, it was necessary to place approximately 70 PPS to achieve intrapedicular accuracy comparable to results reported by experienced surgeons in this minimally invasive technique.
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http://dx.doi.org/10.4103/sni.sni_428_17DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5981185PMC
May 2018

[Minimally invasive extraforaminal lumbar interbody fusion].

Surg Neurol Int 2018 22;9(Suppl 1):S1-S7. Epub 2018 Jan 22.

Departamento de Neurocirugía, Hospital Italiano de Buenos Aires, Argentina.

Objectives: The objective of the present study was to determine the indications, surgical technique, results, and complications of minimally invasive extraforaminal lumbar interbody fusion (ELIF).

Introduction: ELIF is characterized as removal of the superior articular process (SAP) to access the intra-canalicular root and disc through Kambin's triangle.

Methods: A retrospective study was conducted of 40 patients operated upon between 2013 and 2015. Patients with low back pain or root pain due to degenerative disc disease, spondylolisthesis grade 1 and 2, recurrent disc herniation, and recess-foraminal stenosis were included. A visual analogue scale (VAS), the Oswestry index, the Weiner scale and the modified MacNab criteria were used to assess pain, clinical and functional results and patient satisfaction one year after surgery. Complications were documented and rated according to their severity, in four degrees.

Results: We operated on 25 women and 15 men of average age 57 years. Of the forty, 47.5% were treated for spondylolisthesis, 25% by recess foraminal stenosis. In total, 54 interbody cages and 188 percutaneous pedicle screws were placed; and the mean duration of surgery was 245 (±25.4) minutes. The mean hospitalization time was 3.5 (±0.49) days. We observed nine Grade 1 and one Grade 2 complication. The mean preoperative ODI score was 51.9 ± 4.96, which improved to 12.2 ± 3.19 at one year ( < 0.0001). The mean VAS low back pain rating improved from 8.81 ± 0.62 to 2.12 ± 0.89 ( < 0.0001). By one year post-operatively, 77.5% of the patients had fusion (Bridwell grade 1 or 2).

Conclusions: ELIF is a safe and effective surgical approach. Satisfactory clinical outcomes, comparable to traditional techniques, can be achieved with facet resection limited to the superior articular process.
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http://dx.doi.org/10.4103/sni.sni_280_17DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5799939PMC
January 2018

Computed Tomographic Localization of the Central Sulcus: A Morphometric Study in Adult Patients.

Turk Neurosurg 2018 ;28(6):877-881

Instituto Universitario del Hospital Italiano, Buenos Aires, Argentina.

Aim: To accurately describe the relations between the anatomical landmarks of the cranial convexity and the main cortical structures.

Material And Methods: A retrospective cross-sectional, observational study was performed. Computed tomography scans of 71 adult patients with no pathological imaging were analyzed. The position of the bregma and the central sulcus was determined. The distances from bregma to the pre-central and post-central sulci were calculated. The relationships from the nasion and glabella to cortical structures were also assessed.

Results: The mean distances between the bregma and the pre-central, central and post-central sulci were 26.8 ± 7.2; 47.8 ± 5.9 and 60.6 ± 5.7 mm, respectively, without gender discrepancy. The mean distance nasion-bregma and the nasion-related measures showed significant differences among sexes.

Conclusion: The central sulcus was located accurately, on average 47.8 mm behind the bregma, which should be used instead of nasion in order to avoid gender discrepancy. The data obtained provide useful and reliable information to guide neurosurgical procedures.
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http://dx.doi.org/10.5137/1019-5149.JTN.21145-17.1DOI Listing
January 2019

The effect of vancomycin powder on human dural fibroblast culture and its implications for dural repair during spine surgery.

J Neurosurg Spine 2016 Nov 3;25(5):665-670. Epub 2016 Jun 3.

Department of Neurological Surgery, University of Pittsburgh School of Medicine, UPMC Health System, Pittsburgh, Pennsylvania; and.

OBJECTIVE Surgical site infections (SSIs) are a major source of morbidity after spinal surgery. Several recent studies have described the finding that applying vancomycin powder to the surgical bed may reduce the incidence of SSI. However, applying vancomycin in high concentrations has been shown in vitro to inhibit osteoblast proliferation and to induce cell death. Vancomycin may have a deleterious effect on dural healing after repair of an intentional or unintentional durotomy. This study was therefore undertaken to assess the effect of different concentrations of vancomycin on a human dura mater cell culture. METHODS Human dura intended for disposal after decompressive craniectomy was harvested. Explant primary cultures and subcultures were subsequently performed. Cells were characterized through common staining and immunohistochemistry. A growth curve was performed to assess the effect of different concentrations of vancomycin (40, 400, and 4000 μg/ml) on cell count. The effect of vancomycin on cellular shape, intercellular arrangement, and viability was also evaluated. RESULTS All dural tissue samples successfully developed into fusiform cells, demonstrating pseudopod projections and spindle formation. The cells demonstrated vimentin positivity and also had typical features of fibroblasts. When applied to the cultures, the highest dose of vancomycin induced generalized cell death within 24 hours. The mean (± SD) cell counts for control, 40, 400, and 4000 μg/ml were 38.72 ± 15.93, 36.28 ± 22.87, 19.48 ± 6.53, and 4.07 ± 9.66, respectively (p < 0.0001, ANOVA). Compared with controls, vancomycin-exposed cells histologically demonstrated a smaller cytoplasm and decreased pseudopodia formation resulting in the inhibition of normal spindle intercellular arrangement. CONCLUSIONS When vancomycin powder is applied locally, dural cells are exposed to a concentration several times greater than when delivered systemically. In this in vitro model, vancomycin induced dural cell death, inhibited growth, and altered cellular morphology in a concentration-dependent fashion. Defining a safe vancomycin concentration that is both bactericidal and also does not inhibit normal dural healing is necessary.
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http://dx.doi.org/10.3171/2016.3.SPINE151491DOI Listing
November 2016

Pathological changes of the hippocampus and cognitive dysfunction following frontal lobe surgery in a rat model.

Acta Neurochir (Wien) 2016 11 8;158(11):2163-2171. Epub 2016 Sep 8.

Department of Neurosurgery, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina.

Background: Postoperative cognitive dysfunction (POCD) is a known complication after intracranial surgery. Impaired hippocampal neurogenesis has been associated with cognitive dysfunction in animal models.

Methods: In order to assess hippocampal changes after brain surgery, a frontal lobe corticectomy was performed in ten adult Wistar rats (group 4). Three different control groups (n = 10 each) included no treatment (G1), general anesthesia alone (G2), and craniectomy without dural opening (G3). Twenty-four hours after surgery, half of the animals were killed, and the mRNA levels for IL-6, TNF-α, and brain-derived growth factor (BDNF) in the contralateral hippocampus were assessed by qPCR. Seven days later, the remaining animals underwent anxiety and memory testing. Afterwards, the number of immature neurons in the hippocampal cortex was measured by doublecortin (DCX) staining.

Results: Twenty-four hours after surgery, mRNA levels of IL-6 and TNF-α increased and BDNF decreased in both surgical groups G3 and G4 (p = 0.012). Cognitive tests demonstrated an increase in anxiety levels and memory impairment in surgical groups compared with non-surgical animals. These changes correlated with an inhibition of hippocampal neurogenesis evidenced by a decreased number of new neurons (mean ± SD for G1-4: 66.4 ± 24; 57.6 ± 22.2; 21.3 ± 3.78; 5.7 ± 1.05, p < 0.001, non-parametric ANOVA).

Conclusions: Intracranial surgery was demonstrated to induce an inflammatory reaction within the hippocampus that compromised neurogenesis and impaired normal cognitive processing. Corticectomy had a greater effect than craniotomy alone, indicating a central trigger for hippocampal inflammatory changes. POCD after craniotomy may originate from a central inflammatory response resulting from surgical trauma to the brain parenchyma.
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http://dx.doi.org/10.1007/s00701-016-2938-6DOI Listing
November 2016

Construction and in vitro testing of a cellulose dura mater graft.

Neurol Res 2016 Jan;38(1):25-31

c Institute of Basic Science and Experimental Medicine (ICBME) , Hospital Italiano de Buenos Aires , Buenos Aires City , Argentina.

Introduction: Cerebrospinal fluid (CSF) leaks are a common complication after cranial and spinal surgery and are associated with increased morbidity. Despite continuous research in this field, this problem is far from solved. In this paper, we describe the construction and testing of a bacterial cellulose (BC) membrane as a new dural patch.

Materials And Methods: The synthesis of BC was performed using Gluconacetobacter hansenii (ATCC 23769) and films were sterilized by autoclaving. The membranes were seeded with human dural fibroblasts. Growth, shape, and cell viability were assessed after 4 weeks.

Results: Normally shaped fibroblasts were seen on the BC grafts; confocal microscopy showed cells inside the structure of the mesh. Both viable and nonviable cells were present. Cellular attachment and viability were confirmed by replating of the membranes.

Discussion: BC membranes are used in clinical practice to improve skin healing. In the presence of water, they form an elastic, nontoxic, and resistant biogel that can accommodate collagen and growth factors within their structure, thus BC is a good candidate for dural graft construction.
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http://dx.doi.org/10.1080/01616412.2015.1122263DOI Listing
January 2016

Sciatic nerve injury: a simple and subtle model for investigating many aspects of nervous system damage and recovery.

J Neurosci Methods 2014 Apr 30;227:166-80. Epub 2014 Jan 30.

Instituto de Fisiología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina; Instituto de Histología y Embriología - CONICET, Universidad Nacional de Cuyo, Mendoza, Argentina. Electronic address:

Sciatic nerve injury has been used for over a century to investigate the process of nerve damage, to assess the absolute and relative capacity of the central and peripheral nervous systems to recover after axotomy, and to understand the development of chronic pain in many pathologies. Here we provide a historical review of the contributions of this experimental model to our current understanding of fundamental questions in the neurosciences, and an assessment of its continuing capacity to address these and future problems. We describe the different degrees of nerve injury - neurapraxia, axonotmesis, neurotmesis - together with the consequences of selective damage to the different functional and anatomic components of this nerve. The varied techniques used to model different degrees of nerve injury and their relationship to the development of neuropathic pain states are considered. We also provide a detailed anatomical description of the sciatic nerve from the spinal cord to the peripheral branches in the leg. A standardized protocol for carrying out sciatic nerve axotomy is proposed, with guides to assist in the accurate and reliable dissection of the peripheral and central branches of the nerve. Functional, histological, and biochemical criteria for the validation of the injury are described. Thus, this paper provides a review of the principal features of sciatic nerve injury, presents detailed neuroanatomical descriptions of the rat's inferior limb and spine, compares different modes of injury, offers material for training purposes, and summarizes the immediate and longterm consequences of damage to the sciatic nerve.
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http://dx.doi.org/10.1016/j.jneumeth.2014.01.020DOI Listing
April 2014