Publications by authors named "Domagoj Dlaka"

10 Publications

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Structural changes in brains of patients with disorders of consciousness treated with deep brain stimulation.

Sci Rep 2021 Feb 23;11(1):4401. Epub 2021 Feb 23.

Department of Neurosurgery, Dubrava University Hospital, Avenija Gojka Suska 6, 10000, Zagreb, Croatia.

Disorders of consciousness (DOC) are one of the major consequences after anoxic or traumatic brain injury. So far, several studies have described the regaining of consciousness in DOC patients using deep brain stimulation (DBS). However, these studies often lack detailed data on the structural and functional cerebral changes after such treatment. The aim of this study was to conduct a volumetric analysis of specific cortical and subcortical structures to determine the impact of DBS after functional recovery of DOC patients. Five DOC patients underwent unilateral DBS electrode implantation into the centromedian parafascicular complex of the thalamic intralaminar nuclei. Consciousness recovery was confirmed using the Rappaport Disability Rating and the Coma/Near Coma scale. Brain MRI volumetric measurements were done prior to the procedure, then approximately a year after, and finally 7 years after the implementation of the electrode. The volumetric analysis included changes in regional cortical volumes and thickness, as well as in subcortical structures. Limbic cortices (parahippocampal and cingulate gyrus) and paralimbic cortices (insula) regions showed a significant volume increase and presented a trend of regional cortical thickness increase 1 and 7 years after DBS. The volumes of related subcortical structures, namely the caudate, the hippocampus as well as the amygdala, were significantly increased 1 and 7 years after DBS, while the putamen and nucleus accumbens presented with volume increase. Volume increase after DBS could be a result of direct DBS effects, or a result of functional recovery. Our findings are in accordance with the results of very few human studies connecting DBS and brain volume increase. Which mechanisms are behind the observed brain changes and whether structural changes are caused by consciousness recovery or DBS in patients with DOC is still a matter of debate.
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http://dx.doi.org/10.1038/s41598-021-83873-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7902623PMC
February 2021

The Accuracy of Direct Targeting Using Fusion of MR and CT Imaging for Deep Brain Stimulation of the Subthalamic Nucleus in Patients with Parkinson's Disease.

J Neurol Surg A Cent Eur Neurosurg 2021 Feb 22. Epub 2021 Feb 22.

Department of Neurosurgery, Clinical Hospital Dubrava, Zagreb, Croatia.

Introduction:  In 33 consecutive patients with Parkinson's disease (PD) undergoing awake deep brain stimulation (DBS) without microelectrode recording (MER), we assessed and validated the precision and accuracy of direct targeting of the subthalamic nucleus (STN) using preoperative magnetic resonance imaging (MRI) and stereotactic computed tomography (CT) image fusion combined with immediate postoperative stereotactic CT and postoperative MRI, and we report on the side effects and clinical results up to 6 months' follow-up.

Materials And Methods:  Preoperative nonstereotactic MRI and stereotactic CT images were merged and used for planning the trajectory and final lead position. Immediate postoperative stereotactic CT and postoperative nonstereotactic MRI provided the validation of the final electrode position. Changes in the Unified Parkinson's Disease Rating Scale III (UPDRS III) scores and the levodopa equivalent daily doses (LEDD) and appearance of adverse side effects were assessed.

Results:  The mean Euclidian distance (ED) error between the planned position and the final position of the lead in the left STN was 1.69 ± 0.82 mm and that in the right STN was 2.12 ± 1.00. The individual differences between planned and final position in each of the three coordinates were less than 2 mm. The UPDRS III scores improved by 75% and LEDD decreased by 45%. Few patients experienced complications, such as postoperative infection (= 1), or unwanted side effects, such as emotional instability ( = 1).

Conclusion:  Our results confirm that direct targeting of an STN on stereotactic CT merged with MRI could be a valid method for placement the DBS electrode. The magnitude of our targeting error is comparable with the reported errors when using MER and other direct targeting approaches.
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http://dx.doi.org/10.1055/s-0040-1715826DOI Listing
February 2021

Frameless stereotactic brain biopsy: A prospective study on robot-assisted brain biopsies performed on 32 patients by using the RONNA G4 system.

Int J Med Robot 2021 Feb 16. Epub 2021 Feb 16.

Department of Neurosurgery, University Hospital Dubrava, Zagreb, Croatia.

Background: We present a novel robotic neuronavigation system (RONNA G4), used for precise preoperative planning and frameless neuronavigation, developed by a research group from the University of Zagreb and neurosurgeons from the University Hospital Dubrava, Zagreb, Croatia. The aim of study is to provide comprehensive error measurement analysis of the system used for the brain biopsy.

Methods: Frameless stereotactic robot-assisted biopsies were performed on 32 consecutive patients. Post-operative CT and MRI scans were assessed to precisely measure and calculate target point error (TPE) and entry point error (EPE).

Results: The application accuracy of the RONNA system for TPE was 1.95 ± 1.11 mm, while for EPE was 1.42 ± 0.74 mm. The total diagnostic yield was 96.87%. Linear regression showed statistical significance between the TPE and EPE, and the angle of the trajectory on the bone.

Conclusion: The RONNA G4 robotic system is a precise and highly accurate autonomous neurosurgical assistant for performing frameless brain biopsies.
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http://dx.doi.org/10.1002/rcs.2245DOI Listing
February 2021

Stereotactic Neuro-Navigation Phantom Designs: A Systematic Review.

Front Neurorobot 2020 23;14:549603. Epub 2020 Oct 23.

Department of Neurosurgery, University Hospital Dubrava, Zagreb, Croatia.

Diverse stereotactic neuro-navigation systems are used daily in neurosurgery and novel systems are continuously being developed. Prior to clinical implementation of new surgical tools, methods or instruments, experiments on phantoms should be conducted. A stereotactic neuro-navigation phantom denotes a rigid or deformable structure resembling the cranium with the intracranial area. The use of phantoms is essential for the testing of complete procedures and their workflows, as well as for the final validation of the application accuracy. The aim of this study is to provide a systematic review of stereotactic neuro-navigation phantom designs, to identify their most relevant features, and to identify methodologies for measuring the target point error, the entry point error, and the angular error (α). The literature on phantom designs used for evaluating the accuracy of stereotactic neuro-navigation systems, i.e., robotic navigation systems, stereotactic frames, frameless navigation systems, and aiming devices, was searched. Eligible articles among the articles written in English in the period 2000-2020 were identified through the electronic databases PubMed, IEEE, Web of Science, and Scopus. The majority of phantom designs presented in those articles provide a suitable methodology for measuring the target point error, while there is a lack of objective measurements of the entry point error and angular error. We identified the need for a universal phantom design, which would be compatible with most common imaging techniques (e.g., computed tomography and magnetic resonance imaging) and suitable for simultaneous measurement of the target point, entry point, and angular errors.
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http://dx.doi.org/10.3389/fnbot.2020.549603DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7644893PMC
October 2020

A biphasic tumor in posterior cranial fossa and the pineal region in young adult.

Surg Neurol Int 2020 11;11:64. Epub 2020 Apr 11.

Departments of Neurosurgery, University Hospital Dubrava, Zagreb, Croatia.

Background: Biphasic tumors of the central nervous system are rarely described and mainly consisted out of the glial and mesenchymal component. The tumor originated out of both astrocytes and pinealocytes, best to our knowledge, has not been described. We present a case of a brain tumor consisted out of pilocytic astrocytoma (PA) and pineocytoma as components situated in the pineal region and posterior cranial fossa in young adult.

Case Description: We present a 21-year-old patient with a history of intermittent headache, followed by nausea and vomiting, double vision, and dextropulsion. Magnetic resonance imaging revealed an extensive cystic-solid expansive formation in the posterior cranial fossa with a solid part in the area of the pineal gland. The patient underwent surgical resection. The pathohistological analysis showed two types of tumor cells; the major part of tumor showed features of PA, while minor part corresponded to pineocytoma.

Conclusion: PA accounts for 5% of all gliomas and is most common in children and young adults. It usually occurs in the cerebellum, the optic pathway, third ventricular region, etc. Pineocytomas are rare, accounting up to 1% of all intracranial tumors. Since tumors origin is different, there must be complex molecular events or mutations that can lead to cell rearrangements and generation of two histologically different tissues in the same tumor mass. The course of treatment options is different for PA and pineocytoma; therefore, the case of brain mass consisted out of two different tissues can be helpful when deciding about the treatment of tumors in posterior cranial fossa and pineal region.
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http://dx.doi.org/10.25259/SNI_288_2019DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7193197PMC
April 2020

The Dubrava Model-A Novel Approach in Treating Acutely Neurotraumatized Patients in Rural Areas: A Proposal for Management.

J Neurosci Rural Pract 2019 Jul 7;10(3):446-451. Epub 2019 Oct 7.

Department of Neurosurgery, University Hospital Dubrava, Zagreb, Croatia.

Neurotrauma is one of the leading causes of death and disabilities nowadays and represents one of the largest socioeconomic problems in rich countries, as well as developing ones. A satisfying, medically viable, and cost-effective model of managing acutely neurotraumatized patients, especially ones who come from distant and/or rural areas, has yet to be found. Patient outcome after acute neurotrauma depends on many factors of which the possibility of urgent treatment by an experienced specialist team has a crucial role. Here, we present our own way of managing acutely neurotraumatized patients from distant places which is unique in Croatia, the Dubrava model. We present our 5-year experience cooperating with general hospitals in four neighboring cities (Ĉakovec, Bjelovar, Sisak, and Koprivnica) in managing, operating, and taking care of acutely neurotraumatized patients. More than 300 surgeries have been performed in these hospitals through the Dubrava model. Our experience so far provides encouraging results that this system could also be successfully implemented in other institutions. Furthermore, we recorded an increased number of surgeries each year, as well as a good mutual cooperation with the local general hospitals. This trauma managing model is one of a kind in Croatia. We argue that it is not only better for the patients, providing them with better chances of survival, and disability-free recovery, but is also far superior in many ways to the dominant and currently prevalent way of treating these patients in other parts of Croatia. The Dubrava model of treating patients in rural and distant areas is a reliable and proven model with many benefits and as such its implementation should be considered in other institutions as well.
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http://dx.doi.org/10.1055/s-0039-1697777DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6779563PMC
July 2019

Intracranial Mature Teratoma in an Adult Patient: A Case Report.

J Neurol Surg Rep 2019 Jan 3;80(1):e14-e17. Epub 2019 Apr 3.

Department of Neurosurgery, University Hospital Dubrava, Zagreb, Croatia.

: Primary intracranial teratoma is a subtype of germ cell tumors, classified into three subtypes. They occur very rarely, with only several reported individual cases in adults.  We present a patient with an intermittent headache in the right frontal region. Magnetic resonance imaging (MRI) revealed a right sided high frontal parasagittal mass that compressed the falx, the right lateral ventricle, as well as the brain parenchyma. Patient underwent surgical treatment. Histopathological analysis described mature teratoma. Four months after the surgical treatment there were no signs of residual intracranial mass or relapse.  Primary intracranial teratoma in adults has a nonspecific clinical presentation. MRI reveals a solitary irregular mass with multilocularity and mixed signals derived from different tissues. The patients age, biochemical markers, and patohistological analysis are necessary to confirm the diagnosis.  Teratoma treatment strategy still remains controversial. It includes radical resection whenever possible. Since the residual portion of mature teratoma may contain part of immature or malignant tissue, tumor recurrence after surgical removal is possible. Also, new tumor mass could occur at other sites intracranial after the initial one was removed. Thus, although patients usually recover, they should be followed-up for a long period of time.
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http://dx.doi.org/10.1055/s-0039-1685213DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6447400PMC
January 2019

Intraspinal calcinosis mimicking intervertebral disc extrusion: A clinical and surgical case report.

Surg Neurol Int 2018 14;9:166. Epub 2018 Aug 14.

Department of Neurosurgery, Dubrava University Hospital, Zagreb, Croatia.

Background: Subcutaneous calcinosis is a well-recognized manifestation of systemic sclerosis that usually involves multiple pressure points and may also be found in the paraspinal or intraspinal regions. In this case, intraspinal calcinosis uniquely led to a severe neurological deficit.

Case Description: A patient with severe systemic sclerosis/calcinosis exhibited left greater than right lower extremity radiculopathy attributed to intraspinal left-sided L4-L5 calcinosis. On examination, the patient exhibited bilateral positive Lasegue signs, distal lower extremity weakness (left greater than right), and bilaterally decreased Achilles responses. When the magnetic resonance imaging (MRI) revealed a significant intracanalicular mass on the left side at the L4-L5 level, the patient underwent a left-sided L4-L5 decompressive laminectomy. The MRI scan 5 years later revealed no recurrence of the calcinosis, and the patient had no residual neurological deficit.

Conclusions: Spinal calcinosis rarely involves the lumbar spinal canal. Here, a patient with a large left-sided L4-L5 focus of intraspinal calcinosis, mimicking a disc herniation, required a laminectomy to resect the lesion. Lumbar calcinosis should be radiologically evaluated utilizing using X-ray, MRI, and computed tomography studies to adequately document the pathology. Patients, when symptomatic, may require surgical decompression and excision of these lesions.
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http://dx.doi.org/10.4103/sni.sni_147_18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6108162PMC
August 2018

Primary dural lymphoma mimicking meningioma: a clinical and surgical case report.

J Surg Case Rep 2018 Aug 6;2018(8):rjy189. Epub 2018 Aug 6.

Department of Neurosurgery, University Hospital Dubrava, Zagreb, Croatia.

Introduction: Primary central nervous system lymphoma and its subtype, primary dural lymphoma, are types of non-Hodgkin's lymphoma that only occur in the central nervous system without any dissemination. They are extremely rare cases of extra nodal lymphomas accounting for 1--5% of intracranial tumors.

Case Report: We present a patient diagnosed with primary dural lymphoma in right frontal brain region who underwent surgical resection. Histopathological analysis revealed diffuse B-type large cell non-Hodgkin lymphoma. Patient underwent four cycles of R-CHOP and intrathecal methotrexate protocol. Six months postoperative, no signs of newly onset infiltration were present.

Discussion: Primary dural lymphoma most likely presents with unusual radiological signs, which can easily be mistaken for meningioma, the main differential diagnosis. A thorough immunological, histopathological and clinical patients profile should be conducted in order to establish the certainty of diagnosis. Although there are few treatment options: surgery, radiotherapy or chemotherapy, there is no established treatment protocol.
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http://dx.doi.org/10.1093/jscr/rjy189DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6077807PMC
August 2018

Brain biopsy performed with the RONNA G3 system: a case study on using a novel robotic navigation device for stereotactic neurosurgery.

Int J Med Robot 2018 Feb 12;14(1). Epub 2017 Dec 12.

Department of Neurosurgery, University Hospital Dubrava, Zagreb, Croatia.

Background: Robotic neuronavigation is becoming an important tool for neurosurgeons. We present a case study of a frameless stereotactic biopsy guided by the RONNA G3 robotic neuronavigation system.

Methods: A 45 year-old patient with a history of vertigo, nausea and vomiting was diagnosed with multiple periventricular lesions. Neurological status was unremarkable. A frameless robotic biopsy of a brain lesion was performed.

Results: Three tissue samples were obtained. There were no intraoperative or postoperative complications. Histological analysis showed a B-cell lymphoma. After merging the preoperative CT scan with the postoperative MRI and CT scans, the measured error between the planned and the postoperatively measured entry point was 2.24 mm and the measured error between the planned and postoperatively measured target point was 2.33 mm.

Conclusions: The RONNA G3 robotic system was used to navigate a Sedan brain biopsy needle to take tissue samples and could be a safe and precise tool for brain biopsy.
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http://dx.doi.org/10.1002/rcs.1884DOI Listing
February 2018