Diagnostic value of diffusion tensor imaging in patients with clinical signs of cervical spondylotic myelopathy.

AIM OF THE STUDY: The aim of this study was to assess the diagnostic value of diffusion tensor imaging (DTI) in patients with symptoms of cervical myelopathy. Detailed goals included determining the diagnostic effectiveness of quantitative parameters, i.e. fractional anisotropy (FA) and apparent diffusion coefficient (ADC), in the diagnosis of cervical myelopathy, and the correlation between these parameters and clinical symptoms. CLINICAL RATIONALE FOR THE STUDY: The demonstration of an ischaemic focus in the spinal cord by standard magnetic resonance imaging (MRI) methods is associated with already accomplished spinal cord damage, and of course limited treatment options. Therefore, finding a new examination protocol that allows early diagnosis of myelopathic focus, before the onset of full neurological symptoms, has become a priority in the diagnosis and treatment of spine diseases. Such an examination increases the chances of correctly qualifying the patient for conservative vs. surgical treatment. MATERIAL AND METHODS: Between 2013 and 2017, 128 adults with clinical signs of cervical myelopathy were examined, and were divided into four symptomatic subgroups. A control group consisted of 37 healthy volunteers. DTI values were measured at the level of C2/C3, and at the most severe stenosis of the spine. RESULTS: In patients with cervical spondylotic myelopathy (CSM), the ADC values were significantly higher (p < 0.001), and FA values were significantly lower (p < 0.001), than in healthy volunteers at the stenotic level. There were significant differences in DTI parameters between the clinical subgroups (p < 0.001). CONCLUSIONS AND CLINICAL IMPLICATIONS: Changes in DTI parameters indicate a microstructural disorder of the core which is not visible in a structural MRI. FA and ADC values measured at the level of the most severe stenosis of the spinal canal allow the differentiation of patients with myelopathy of varying degrees of clinical severity. Extending standard MRI to include assessment of FA and ADC may be helpful in deciding treatment modalities (conservative vs. surgical) for patients with visible canal stenosis without full neurological symptoms. This may be useful in selecting patients for urgent rehabilitative treatment. This study is a starting point for further research, i.e. an evaluation of the extent of FA and ADC lesion withdrawal after surgical treatment.

Can sectioning the posterior communicating artery be predicted with computed tomography angiography in the microsurgical clipping of basilar apex aneurysms?

BACKGROUND: Microsurgical clipping is a viable option for managing high-riding basilar apex aneurysms (BAXs) using a transsylvian approach. Cutting the posterior communicating artery (PCoA) at the perforator-free zone provides sufficient exposure of BAX, although it is not always safe. The aim was to qualitatively predict sectioning of the interfering PCoA by using preoperative computed tomographic angiography (CTA). METHODS: A virtual trajectory from the lesser sphenoid wing to the neck of the aneurysm was simulated on CTA in 19 consecutive patients operated on BAX aneurysms from 2013 to 2018. The angles on CTA resembled the typical view through the extended pterional craniotomy. Next, the ipsilateral PCoA was tracked from the internal carotid to its end at the posterior cerebral artery in the trajectory. RESULTS: The opticocarotid and carotid-oculomotor window served as the corridors for entering the interpeduncular fossa in 16 patients (84.2%) and in 3 patients (15.8%), respectively. The PCoA was intentionally cut during nine surgeries and preserved in 10 of them. The PCoA was cut more often when positioned toward the cranial base and more medially in the corridor; both the Kernel density analysis and the data points representing the position of the PCoA supported this finding (p < 0.01). The CTA-based position of either ends of the PCoA in the trajectory did not differ between cut and not-cut groups (p = 0.19-0.96). Aneurysm projection, rupture, size, PCoA diameter, length, and other distances on CTA were not related to the sectioning of PCoA (p > 0.05). CONCLUSIONS: The probability of PCoA sectioning is higher when the PCoA is positioned medially and closer to the cranial base. If the anatomical course of the PCoA is recognized beforehand, it can contraindicate surgery. Preoperative CTA-based planning facilitates the surgery of BAX aneurysms. Therefore, CTA can make microsurgical clipping planning more predictable for the neurosurgeon and safer for the patient.

Extent of anterior clinoidectomy for clipping of carotid-ophthalmic aneurysms predicted on three-dimensional computerised tomography angiography.

AIM OF STUDY: We aimed to verify the value of computerised tomography angiography (CTA) on predicting the extent of anterior clinoidectomy that is optimal for particular carotid-ophthalmic aneurysms (COAs). CLINICAL RATIONALE FOR STUDY: The anterior clinoid process (ACP) often impedes the complex microsurgery of COA. Complete removal of the ACP ensures safe clipping; however, it also may increase the risk of severe complications. The probability of performing a successful partial anterior clinoidectomy could be evaluated by preoperative CTA. MATERIALS AND METHODS: 28 patients with either a ruptured (n=4) or unruptured COA were included in this prospective, single-centre, observational study. One aneurysm was giant, two were large, and the rest were smaller. Successful aneurysm clipping was the aim in all cases. The anterior clinoidectomy was preoperatively planned on multiplanar three-dimensional reconstructions of CTA images (3D-CTA) which resembled the typical view of a frontotemporal craniotomy. Finally, the predicted clinoidectomy was compared to the extent of the actual clinoidectomy. RESULTS: 21 aneurysms (75%) projected superolateral or superior. The ACP was completely and selectively resected in 25% (7 of 28) and 67.9% of patients (19 of 28) respectively. Optic nerve (ON) unroofing was always performed in the case of total anterior clinoidectomy, but accompanied only 8 of 19 selective clinoidectomies (p = 0.03). The extent of the actual clinoidectomy was predicted by the 3D-CTA-based preoperative planning in 17 of 27 cases (63.0%). Particularly, prediction of the osteotomy was correct in 85.7% of complete, 62.5% of selective lateral, and 57.1% of medial clinoidectomy. None of the radiological and clinical factors determined the correlation between the planned and the actual extent of ACP removal. There was one incomplete occlusion among 23 obtained follow-up CTAs. CONCLUSIONS: The predictive value of 3D-CTA on the extent of anterior clinoidectomy still remains unsatisfactory; it is limited by the individual variability of COA and its surrounding structures. CLINICAL IMPLICATIONS: Currently, the role of 3D-CTA planning is restricted to educational purposes only.

Morphometric Analysis of the Lumbar Vertebrae Concerning the Optimal Screw Selection for Transpedicular Stabilization.

Transpedicular stabilization is a frequently used spinal surgery for fractures, degenerative changes, or neoplastic processes. Improper screw fixation may cause substantial vascular or neurological complications. This study seeks to define detailed morphometric measurements of the pedicle (height, width, and surface area) in the aspects of screw length and girth selection and the trajectory of its implantation, i.e., sagittal and transverse angle of placement. The study was based on CT examinations of 100 Caucasian patients (51 women and 49 men) aged 27-75 with no anatomical, degenerative, or post-traumatic spine changes. The results were stratified by gender and body side, and they were counter compared with the available literature database. Pedicle height decreased from L1 to L4, ranging from 15.9 to 13.3 mm. Pedicle width increased from L1 to L5, extending from 6.1 to 13.2 mm. Pedicle surface area increased from L1 to L5, ranging from 63 to 140 mm2. Distance from the point of entry into the pedicle to the anterior surface of the vertebral body, defining the maximum length of a transpedicular screw, varied from 54.0 to 50.2 mm. Variations concerning body sides were inappreciable. A transverse angle of screw trajectory extended from 20° to 32°, shifting caudally from L1 to L5, with statistical differences in the L3-L5 segments. A sagittal angle varied from 10° to 12°, without such definite relations. We conclude that the L1 and L2 segments display the most distinct morphometric similarities, while the greatest differences, in both genders, are noted for L3, L4, and L5. The findings enable the recommendation of the following screw diameters: 4 mm for L1-L2, 5 mm for L3, 6 mm for L4-L5, and the length of 50 mm. We believe the study has extended clinical knowledge on lumbar spine morphometry, essential in the training physicians engaged in transpedicular stabilization.

The "Optimum Volume" of Acrylic Cement Filling for Treating Vertebral Compression Fractures: A Morphometric Study of Thoracolumbar Vertebrae.

Percutaneous vertebroplasty is a treatment option in vertebral compression fractures (VCF). The aim of the study was to propose the mathematical calculation of the "optimum volume" of acrylic cement filling of the vertebral body, depending on the severity of a fracture. Two hundred computed tomography (CT) scans of vertebral columns in healthy adult Caucasians were analyzed. Vertebral body width (VBW), vertebral body depth (VBD), vertebral body height (VBH), and vertebral body volume (VBV) were measured. The "optimum volume" of cement injections in mild (25% collapse) and moderate (40% collapse) VCF were calculated. We found that moving caudally from Th11 to L2, the mean values of the examined parameters increased: VBH from 22.6 to 26.0 mm, VBW from 34.0 to 39.5 mm, VBD from 28.1 to 30.9 mm, and VBV from 17.1 to 24.8 cm3. The calculated hypothetical "optimum volume" of cement injection increased from 7.4 to 10.0 cm3 in mild VCF and from 5.9 to 7.8 cm3 in moderate VCF, with some variability depending on the vertebral level and gender. These values are akin to those present in other past studies. We conclude that morphometric measurements, based on CT images, are a reliable source of practical anatomical savvy, which may be of help in spine surgery.

Relative Cerebral Blood Transit Time Decline and Neurological Improvement in Patients After Internal Carotid Artery Stenting.

In this study we hypothesized that the alleviation of neurological symptoms long after internal carotid artery (ICA) stenting may be related to sustained improvement of cerebral perfusion. Thirty-four subjects (F/M; 15/19) with >70% stenosis of a single internal carotid artery and neurological symptoms, who underwent a carotid artery stenting procedure, were studied. Brain computed tomography perfusion (CTP) imaging was performed before and 3 years after ICA stenting. The following relative variables were compared: cerebral blood flow (rCBF), cerebral blood volume (rCBV), mean transit time (rMTT), time to peak (rTTP), and permeability surface area product (rPS). A survey also was conducted to compare the patients' clinical symptoms. Overall, we found that a trend toward rMTT decline was the only persisting change after ICA stenting. We then stratified the patients into the subgroups of <2%, 2-5%, and > 5% rMTT decline and found that those with a rMTT decline >2% reported a prominent reduction in subjective clinical symptoms such as headache, dizziness, tinnitus, blurred vision, transient blindness, a sense of gravity of the head, and pain in the eyeballs. We conclude that a shortened mean rMTT, likely reflecting improved cerebral microcirculation, underlies the improvement of neurological symptoms in patients with ICA stenosis.

Radiation safety awareness among medical staff.

BACKGROUND: The common access to imaging methods based on ionizing radiation requires also radiation protection. The knowledge of ionizing radiation exposure risks among the medical staff is essential for planning diagnostic procedures and therapy. Evaluation of the knowledge of radiation safety during diagnostic procedures among the medical staff. MATERIAL/METHODS: The study consisted of a questionnaire survey. The questionnaire consisted of seven closed-ended questions concerning the knowledge of the effects of exposure to ionizing radiation as well as questions related to responder's profession and work experience. The study group included a total of 150 individuals from four professional groups: nurses, doctors, medical technicians, support staff. The study was carried out in the three largest hospitals in Gdansk between July and October 2013. RESULTS: The highest rates of correct answers to questions related to the issue of radiation protection were provided by the staff of radiology facilities and emergency departments with 1-5 years of professional experience. The most vulnerable group in terms of the knowledge of these issues consisted of individuals working at surgical wards with 11-15 years of professional experience. CONCLUSIONS: Education in the field of radiological protection should be a subject of periodic training of medical personnel regardless of position and length of service.

The challenges of hypervolemic therapy in patients after subarachnoid haemorrhage.

PURPOSE: The triple-H therapy is widely used for cerebral vasospasm (CV) prevention and treatment in patients after subarachnoid haemorrhage (SAH). However, this practice is based on low level evidence. Aim of this study was to evaluate errors in fluid administration, fluid balance monitoring and bedside charts completeness during a trial of triple-H therapy. MATERIALS AND METHODS: An audit of the SAH patient charts was performed. A total of 508 fluid measurements were performed in 41 patients (6 with delayed cerebral ischaemia; DCI) during 14 days of observation. RESULTS: Underestimating for intravenous drugs was the most frequent error (80.6%; 112), resulting in a false positive fluid balance in 2.4% of estimations. In 38.6% of the negative fluid balance cases, the physicians did not order additional fluids for the next 24h. In spite of that, the fluid intake was significantly increased after DCI diagnosis. The mean and median intake values were 3.5 and 3.8l/24h respectively, although 40% of the fluid balances were negative. The positive to negative fluid balance ratio was decreasing in the course of the 14 day observation. CONCLUSIONS: This study revealed inconsistencies in the fluid orders as well as mistakes in the fluid monitoring, which illustrates the difficulties of fluid therapy and reinforces the need for strong evidence-based guidelines for hypervolemic therapy in SAH.

Dural metastasis of prostate carcinoma mimicking intracranial hematoma: a case report and literature review.

Dural metastases of prostate adenocarcinoma are an extremely rare complication and may mimic intracranial hematoma. Preoperatively diagnosis may be difficult due to similarities in symptoms and radiological appearance. We present a 65-year-old man admitted to the ED with a history of headache, nausea, vomiting, vertigo, diplopia, as well as numbness of his left lower extremity. Past medical history confirmed metastatic prostate cancer disease. After computed tomography and contrast computed tomography, the consulting radiologist diagnosed a chronic subdural hematoma. After burr hole trephination and dural opening, tumorous mass was detected. Histopathologic samples were taken. Histopathological examination was consistent with metastatic adenocarcinoma of the prostate. Although rare, dural metastases need to be included in oncological patients presenting in the ED with symptoms and radiological imaging suggesting hematoma. Both neurooncological and neurosurgical consultations are essential in order to apply the best treatment strategy.

Predictors of postoperative mortality in ruptured aneurysms of internal carotid artery.

BACKGROUND AND PURPOSE: An analysis of predictors of mortality in patients with ruptured intracranial aneurysm is an important aspect in the assessment of outcome. The aim of the study was to analyse factors determining mortality risk after the surgical treatment of ruptured internal carotid artery (ICA) aneurysm. MATERIAL AND METHODS: This study comprised 242 patients operated on between 1997 and 2006 in the Neurosurgery Department of the Medical University Hospital in Gdansk, Poland. Multivariate logistic regression, ROC curves (for model assessment as a mortality classifier) and population attributable risk for contribution of individual factor mortality explanation were used to assess factors related to in-hospital mortality. RESULTS: 14.9% of patients died postoperatively. In univariate analysis, increased risk of death was related to the Glasgow Coma Scale score, WFNS score, Hunt-Hess and Fisher grade, preoperative neurological deficit, delayed cerebral ischaemia (DCI), trapping and bypass operative method. Multivariate analysis revealed two independent predictors of in-hospital mortality: DCI and Hunt-Hess grade. 91% of mortality risk was attributed to grade 4 or 5 in Hunt-Hess scale and DCI. The dominant predictor of survival was the Hunt-Hess scale. Increase by one grade in the Hunt-Hess scale resulted in two-fold increase of in-hospital mortality risk. CONCLUSIONS: Postoperative mortality after ICA aneurysm rupture is determined by clinical status at admission and the occurrence of DCI.

Modified bedside twist drill craniostomy for evacuation of chronic subdural haematoma.

INTRODUCTION: Standard craniotomy (SC) and burr hole craniostomy (BHC) are regarded as the standard approaches to chronic subdural haematoma (CSDH). Bedside twist drill craniostomy (TDC), performed at the patient's bedside, was introduced as an alternative to the standard methods. However, clinical and radiological features of patients treated with TDC and BHC/SC have not been compared. AIM: To demonstrate the specific features of CSDH that affect the surgeons' preferences when selecting patients for TDC. MATERIAL AND METHODS: A retrospective analysis of 32 patients treated due to CSDH in the year 2017 at a single institution was performed. Baseline radiological characteristics, clinical status at admission, complication rate and clinical outcomes were compared between BHC/SC and TDC. RESULTS: Of the 32 patients, 5 (15.6%) were treated using TDC and 27 (84.4%) by SC or BHC. The duration of the TDC procedure was significantly shorter than the time of standard therapies (p < 0.01). There were no differences between TDC and BHC/SC in terms of baseline clinical characteristics, including age, gender, head trauma history, diabetes, hypertension, antiplatelet drug use, clinical manifestation and the Glasgow Coma Scale score (all p > 0.05). Patients treated with TDC had a significantly thicker haematoma (TDC vs. BHC/SC: mean 25.3 mm vs. 14.6 mm) (p < 0.01) and demonstrated a smaller midline shift (TDC vs. BHC/SC: mean 0.5 mm vs. 4.0 mm) (p = 0.01) compared to those treated with BHC/SC. CONCLUSIONS: Twist drill craniostomy is a more effective method for CSDH evacuation compared to SC and BHC. This procedure is considered as the first line treatment for patients with a thicker and non-septated haematoma, and with a smaller midline shift.

Computed tomography indicators of cerebral microperfusion improve long term after carotid stenting in symptomatic patients.

OBJECTIVES: We tested the hypothesis that computed tomography (CT) perfusion markers of cerebral microcirculation would improve 36 months after internal carotid artery stenting for symptomatic carotid stenosis while results obtained 6-8 weeks after the stenting procedure would yield a predictive value. METHODS: We recruited consecutive eligible patients with >70% symptomatic carotid stenosis with a complete circle of Willis and normal vertebral arteries to the observational cohort study. We detected changes in the cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), time to peak (TTP) and permeability surface area-product (PS) before and after carotid stenting. We have also compared the absolute differences in the ipsilateral and contralateral CT perfusion markers before and after stenting. The search for regression models of "36 months after stenting" results was based on a stepwise analysis with bidirectional elimination method. RESULTS: A total of 34 patients completed the 36 months follow-up (15 females, mean age of 69.68±S.D. 7.61 years). At 36 months after stenting, the absolute values for CT perfusion markers had improved: CBF (ipsilateral: +7.76%, contralateral: +0.95%); CBV (ipsilateral: +5.13%, contralateral: +3.00%); MTT (ipsilateral: -12.90%; contralateral: -5.63%); TTP (ipsilateral: -2.10%, contralateral: -4.73%) and PS (ipsilateral: -35.21%, contralateral: -35.45%). MTT assessed 6-8 weeks after stenting predicted the MTT value 36 months after stenting (ipsilateral: R2=0.867, contralateral R2=0.688). CONCLUSIONS: We have demonstrated improvements in CT perfusion markers of cerebral microcirculation health that persist for at least 3 years after carotid artery stenting in symptomatic patients. MTT assessed 6-8 weeks after stenting yields a predictive value.

The influence of propofol on middle cerebral artery flow velocity (VMCA) in patients with unruptured intracranial aneurysms during induction of general anaesthesia.

BACKGROUND: The estimated prevalence of unruptured intracranial aneurysms is 3%. Standard monitoring does not enable one to assess the influence of anaesthetics on the factors determining intracranial homeostasis. Thanks to transcranial Doppler ultrasonography, middle cerebral artery flow velocity (VMCA), reflecting cerebral blood flow, can be measured. The aim of the study was to assess the effects of propofol on intracranial homeostasis in patients with unruptured intracranial aneurysms during the induction of anaesthesia based on VMCA changes. METHODS: The study encompassed 21 patients (group II) anaesthetised for elective craniotomy due to unruptured intracranial aneurysms. The control group (group I) included 21 patients who underwent discoidectomy. VMCA, as well as HR, MAP, etCO2, and SpO2 were monitored at the following time points: T0 ­ onset of study; T1 ­ after 1 minute; T2 ­ onset of preoxygenation; T3 ­ after 1 minute of preoxygenation; T4 ­ administration of fentanyl; T5 ­ 1 minute after fentanyl; T6 ­ administration of propofol; T7 ­ 1 minute after propofol; T8 ­ intubation; T9 ­ 1 minute after intubation; T10 ­ 2 minutes after intubation. RESULTS: In both groups, no changes in mean HR, etCO2 and SpO2 were observed at the successive time points of observation. In groups I and II, an MAP decrease between T6 and T7 and an MAP increase between T7 and T9 were noted. There were no intergroup differences in mean values of MAP at the times of observation. In both groups and bilaterally, a VMCA decrease was recorded between T6 and T7 and an increase between T7 and T8. There were no intergroup differences in mean values of VMCA at the times of observation. In both groups, a weak correlation between VMCA and MAP changes was found bilaterally. CONCLUSIONS: Propofol depresses the cerebral circulation during the induction of anaesthesia. The presence of an unruptured aneurysm does not affect the reactivity of the cerebral vessels during the induction of anaesthesia with propofol.

Regional resting state perfusion variability and delayed cerebrovascular uniform reactivity in subjects with chronic carotid artery stenosis.

The aim of this study was to assess regional perfusion at baseline and regional cerebrovascular resistance (CVR) to delayed acetazolamide challenge in subjects with chronic carotid artery stenosis. Sixteen patients (ten males) aged 70.94±7.71 with carotid artery stenosis ≥ 90% on the ipsilateral side and ≤ 50% on the contralateral side were enrolled into the study. In all patients, two computed tomography perfusion examinations were carried out; the first was performed before acetazolamide administration and the second 60 minutes after injection. The differences between mean values were examined by paired two-sample t-test and alternative nonparametric Wilcoxon's test. Normality assumption was examined using W Shapiro-Wilk test. The lowest resting-state cerebral blood flow (CBF) was observed in white matter (ipsilateral side: 18.4±6.2; contralateral side: 19.3±6.6) and brainstem (ipsilateral side: 27.8±8.5; contralateral side: 29.1±10.8). Grey matter (cerebral cortex) resting state CBF was below the normal value for subjects of this age: frontal lobe - ipsilateral side: 30.4±7.0, contralateral side: 33.7±7.1; parietal lobe - ipsilateral side: 36.4±11.3, contralateral side: 42.7±9.9; temporal lobe - ipsilateral side: 32.5±8.6, contralateral side: 39.4±10.8; occipital lobe - ipsilateral side: 24.0±6.0, contralateral side: 26.4±6.6). The highest resting state CBF was observed in the insula (ipsilateral side: 49.2±17.4; contralateral side: 55.3±18.4). A relatively high resting state CBF was also recorded in the thalamus (ipsilateral side: 39.7±16.9; contralateral side: 41.7±14.1) and cerebellum (ipsilateral side: 41.4±12.2; contralateral side: 38.1±11.3). The highest CVR was observed in temporal lobe cortex (ipsilateral side: +27.1%; contralateral side: +26.1%) and cerebellum (ipsilateral side: +27.0%; contralateral side: +34.6%). The lowest CVR was recorded in brain stem (ipsilateral side: +20.2%; contralateral side: +22.2%) and white matter (ipsilateral side: +18.1%; contralateral side: +18.3%). All CBF values were provided in milliliters of blood per minute per 100 g of brain tissue (ml/100g/min). Resting state circulation in subjects with carotid artery stenosis is low in all analysed structures with the exception of insula and cerebellum. Acetazolamide challenge yields relatively uniform response in both hemispheres in the investigated population. Grey matter is more reactive to acetazolamide challenge than white matter or brainstem.

Frequent expression of somatostatin receptor 2a in olfactory neuroblastomas: a new and distinctive feature.

Olfactory neuroblastoma (ONB) is a malignant neuroendocrine neoplasm with a usually slow course, but with considerable recurrence rate. Many neuroendocrine tumors have shown good response to the treatment with somatostatin analogs and somatostatin radioreceptor therapy. In ONBs, there are scarce data on somatostatin-based treatment and the cellular expression of somatostatin receptors (SSTR), the prerequisite for binding and effect of somatostatin on normal and tumor cells. The aim of our study was to investigate the immunohistochemical expression of SSTR2A and SSTR5 in a cohort of 40 ONBs. In addition, tissue microarrays containing 40 high-grade sinonasal carcinomas as well as 6 sinonasal lymphomas, 3 rhabdomyosarcomas, and 3 Ewing sarcomas were evaluated. Volante system was applied for staining evaluation. Thirty cases (75%) were immunopositive for SSTR2A and 3 (7.5%) for SSTR5. Among the 30 SSTR2A-positive ONBs, 19 tumors (63.3%) scored 2+ and 11 (36.7%) scored 3+. All SSTR5-positive ONBs scored 2+. Neither sinonasal carcinomas nor sinonasal small round blue cell neoplasms expressed SSTR2A or SSTR5. The frequent expression of SSTR2A provides a rationale for radioreceptor diagnosis and therapy with SST analogs in ONBs. SSTR2A expression in ONBs is a helpful adjunct in the differential diagnosis of ONBs.

Assessment of the Relationship between the Shape of the Lateral Meniscus and the Risk of Extrusion Based on MRI Examination of the Knee Joint.

BACKGROUND: Meniscus extrusion is a serious and relatively frequent clinical problem. For this reason the role of different risk factors for this pathology is still the subject of debate. The goal of this study was to verify the results of previous theoretical work, based on the mathematical models, regarding a relationship between the cross-section shape of the meniscus and the risk of its extrusion. MATERIALS AND METHODS: Knee MRI examination was performed in 77 subjects (43 men and 34 women), mean age 34.99 years (range: 18-49 years), complaining of knee pain. Patients with osteoarthritic changes (grade 3 and 4 to Kellgren classification), varus or valgus deformity and past injuries of the knee were excluded from the study. A 3-Tesla MR device was used to study the relationship between the shape of the lateral meniscus (using slope angle, meniscus-cartilage height and meniscus-bone angle) and the risk of extrusion. RESULTS: Analysis revealed that with values of slope angle and meniscus-bone angle increasing by one degree, the risk of meniscus extrusion raises by 1.157 and 1.078 respectively. Also, an increase in meniscus-cartilage height by 1 mm significantly elevates the risk of extrusion. At the same time it was demonstrated that for meniscus-bone angle values over 42 degrees and slope angle over 37 degrees the risk of extrusion increases significantly. CONCLUSIONS: This was the first study to demonstrate a tight correlation between slope angle, meniscus-bone angle and meniscus-cartilage height values in the assessment of the risk of lateral meniscus extrusion. Insertion of the above parameters to the radiological assessment of the knee joint allows identification of patients characterized by an elevated risk of development of this pathology.

Neurosurgical stereomorphometry in vivo--method description and error measurement.

Rules of geometry and stereomorphometry are often applied to narrow and deep neurosurgical approaches. Methods of research are based on the direct cadaver measurements, radiological analysis and intraoperative measurements. Newly developed devices allow direct morphometry to be performed in vivo, during the operation. We describe the use of the neuronavigation system Stealth Station by Medtronic for such stereomorphometric measurements and evaluate the precision of the described method.

Minimally invasive surgical techniques for the treatment of lumbar disc disease.

The goal of minimally invasive surgery in the treatment of lumbar discopathy is to achieve outcomes comparable to those of conventional surgery, with minimal risk of perioperative iatrogenic injury. Over the last two decades we have observed remarkable progress in the development of new surgical techniques: chemonucleolysis, transcutaneous discoidectomy, laser discoidectomy, intradiscal thermoablation, and other minimally invasive techniques. Laparoscopy, originally used in general surgery, has made its appearance in lumbar spinal surgery, and has found application in discoidectomy and anterior fixation. The further development of optics, imaging techniques, and new surgical instruments especially designed for minimally invasive spinal surgery are opening the way to completely new methods of treatment.

Lumbar disc surgery in historical perspective.

The development of microscopy, laser technology, endoscopy, and video and image guidance systems has provided the foundation on which minimally invasive spinal surgery is based. Minimally invasive treatments have been undertaken in all areas of the spinal axis since the 20th century. Lumbar disc disease has been treated using chemonucleolysis, percutaneous discectomy, laser discectomy, intradiscal thermoablation, and minimally invasive microdiscectomy techniques.

Effect of sevoflurane on cerebral perfusion pressure in patients with internal hydrocephalus.

BACKGROUND: Due to its confirmed neuroprotective properties, sevoflurane is one of a few anaesthetics used for neuroanaesthesia. Its effects on the cerebral and systemic circulations may be of particular importance in patientswith intracranial pathology. This study aimed to evaluate the effect of sevoflurane at concentrations lower than 1 MAC on cerebral perfusion pressure (CPP) in patients with internal hydrocephalus. METHODS: The study was conducted on14 patients with internal hydrocephalus, who underwent ventriculo-peritoneal shunt implantation. After inserting the catheter into the lateral cerebral ventricle, sevoflurane, at 1.1 and 2.2 vol%, was initiated at two successive 15-minute intervals. The intracranial pressure (ICP) was continuously measured; special attention was focused on the values prior to and at the end of each observation period. The following parameters were monitored: mean arterial pressure (MAP), CPP, heart rate, end-tidal CO2 concentration, core body temperature, and the inspiratory and end-expiratory concentrations of sevoflurane. RESULTS: The HR and MAP decreased during successive observation intervals compared to baseline values. Likewise, the CPP decreased from 75.6 ± 2.8 mm Hg to 72.2 ± 2.6 mm Hg to 70.2 ± 0.8 mm Hg. The baseline value for ICP was 16.3 ± 0.6 mm Hg and increased to 17.7 ± 0.8 and 18.9 ± 0.5 mm Hg during the next observation periods. CONCLUSIONS: Sevoflurane administered ata concentration below 1MAC to patients with internal hydrocephalus increases the ICP and decreases the MAP, which leads to adecrease in CPP. The CPP decrease is more dependent on depressing the systemic circulatory system than an increased ICP.