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BACKGROUND CONTEXT: The majority of surgical training is conducted in real-world operations. High-fidelity surgical simulators may provide a safer environment for surgical training. However, the extent that it reflects real-world operations and surgical ability is often poorly characterized. PURPOSE: (1) Assess the validity and fidelity of a surgical simulator; (2) Examine the quantitative relationship between simulation performance and markers of real-world ability; (3) Establish thresholds for surgical expertise, and estimate their external validity and accuracy. STUDY DESIGN/SETTING: A cohort study of surgeons at a British neurosurgical center. STUDY SAMPLE: 10 early-career "novice" surgeons and 8 board-certified "expert" neurosurgeons. OUTCOMES MEASURES: (1) Face and content validity, and visual and haptic fidelity; (2) Construct validity; (3) Predictive and discriminative utility of quantitative performance thresholds. METHODS: Participants performed unilateral lumbar decompressions on high-fidelity spinal simulators that replicate the bony and soft tissue anatomy along with physiological processes such as bleeding and CSF leaks. Operating times, measured from first surgical action to either self-perceived satisfactory decompression or the end of allocated time, were recorded. The performance was also assessed independently by two blinded spinal subspecialist neurosurgeons using OSATS, a validated surgical assessment tool that utilizes five-point scales on a variety of technical domains to grade the overall technical proficiency. Validity and fidelity were assessed by expert neurosurgeons using quantitative questionnaires. Construct validity was assessed by ordinal regression of simulation performance against real-world surgical grade and portfolio. Thresholds of expert status by simulation performance was established, and their predictive and discriminative utility assessed by crossvalidation accuracy and AUC-ROC. RESULTS: Operating time and expert assessments of simulation performance (OSATS) were strong and significant predictors of surrogate markers of real-world surgical ability. The thresholds for expert status were operating time of 15 minutes and modified OSATS score of 15/20. These thresholds predicted expert status with 84.2% and 71.4% accuracy respectively. Strong discriminative ability was demonstrated by AUC-ROC of 0.95 and 0.83 respectively. All expert surgeons agreed that RealSpine simulators demonstrate high face validity, and high visual and haptic fidelity, with overall scores showing statistically significant agreement on these items (all scores at least 4/5, P<.0001). There was less consensus on content validity, but with still significant overall agreement (average score: 3.75/5, P=0.023). CONCLUSIONS: Real-world surgical ability and experience can be accurately predicted by defining objective quantitative thresholds on high-fidelity simulations. The thresholds established here, along with other data presented in this paper, may inform objectives and standards to be established in a spinal surgical training curriculum.
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BACKGROUND: Clinicians are well-versed in the classical symptoms of low vs. high intracranial pressure (ICP). However, symptoms may not be as predictable of ICP state in shunted patients with chronic symptoms. In this study, we assess whether clinicians can predict high vs. low ICP state in chronically symptomatic shunted patients without any diagnostic clues. METHODS: A detailed retrospective analysis was performed on 259 patients undergoing ICP monitoring. A total of 17 patients who had a ventriculoperitoneal shunt were identified, with a suspected chronic abnormal ICP state based only on clinical symptoms. Patients with investigations guiding towards a likely pressure state were excluded, e.g., imaging or ophthalmological findings suggestive of ICP state. RESULTS: Clinical suspicion of ICP state was incorrect in 16 out of 17 cases (P<0.05). The symptoms described by patients were suggestive of abnormal ICP states; however, 13 out of 17 cases demonstrated ICP within the normal range (-1.3 to 5.3 mmHg). Three patients with occipital headaches worse on standing, typical of low-pressure symptoms, were in fact shown to have ICP above 10.0 mmHg. CONCLUSIONS: This study casts doubt on the utility of classic symptoms in diagnosing abnormal ICP state in chronically symptomatic shunted patients with equivocal adjuncts. Additionally, it highlights the importance of ICP monitoring for this patient group.
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BACKGROUND: Elective use of intraparenchymal intracranial pressure (ICP) monitoring is a valuable resource in the investigation of hydrocephalus and other cerebrospinal fluid disorders. Our preliminary study aims to investigate ICP changes in the immediate period following dural breach, which has not yet been reported on. METHOD: This is a prospective cohort study of patients undergoing elective ICP monitoring, recruited between March and May 2022. ICP readings were obtained at opening and then at 5-min intervals for a 30-min duration. RESULTS: Ten patients were recruited, mean age 45 years, with indications of a Chiari malformation (n = 5), idiopathic intracranial hypertension (n = 3) or other ICP-related pathology (n = 2). Patients received intermittent bolus sedation (80%) vs general anaesthesia (20%). Mean opening pressure was 22.9 mmHg [± 6.0], with statistically significant decreases present every 5 min, to a total reduction of 15.2 mmHg at 20 min (p = < 0.0001), whereafter the ICP plateaued with no further statistical change. DISCUSSION: Our results highlight an intracranial opening pressure 'spike' phenomenon. This spike was 15.2 mmHg higher than the plateau, which is reached at 20 min after insertion. Several possible causes exist which require further research in larger cohorts, including sedation and pain response. Regardless of causation, this study provides key information on the use of ICP monitoring devices, guiding interpretation and when to obtain measurements.
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Malformação de Arnold-Chiari , Hidrocefalia , Hipertensão Intracraniana , Pseudotumor Cerebral , Humanos , Pessoa de Meia-Idade , Pressão Intracraniana/fisiologia , Estudos Prospectivos , Hidrocefalia/complicações , Pseudotumor Cerebral/complicações , Malformação de Arnold-Chiari/complicações , Monitorização Fisiológica/métodos , Hipertensão Intracraniana/diagnóstico , Hipertensão Intracraniana/etiologiaRESUMO
INTRODUCTION: The cerebrospinal fluid (CSF) production rate in humans is not clearly defined but is estimated to be 18-24 ml/h (Trevisi et al Croat Med J 55(4):377-387 (24); Casey and Vries Childs Nerv Syst 5(5):332-334 (8)). A frequent clinical observation is that patients often drain higher volumes of CSF than can be explained by the assumed 'normal' CSF production rate (PRcsf). In the National Hospital for Neurology and Neurosurgery PRcsf was recorded in a variety of common neurosurgical pathologies using LiquoGuard7, an automated peristaltic pump that accurately controls CSF drainage and maintains a pre-set CSF pressure. METHODS: A prospective observational study was performed from September 2021 onwards, on all patients in the National Hospital for Neurology and Neurosurgery who required CSF drainage as part of their ongoing treatment. The external drain was connected to a LiquoGuard7 pump (Möller Medical GmbH, Fulda, Germany), and the internal software of LiquoGuard7 was used to measure PRcsf. Statistical analysis used SPSS (version 25.0, IBM) by paired t test, comparing measured rates to hypothetical 'normal' CSF production rates calculated and published by Ekstedt (16-34ml/h) (Ekstedt J Neurol Neurosurg Psychiatry 41(4):345-353 (14)), assuming a similar distribution. RESULTS: PRcsf was calculated in 164 patients. Suspected normal pressure hydrocephalus (n=41): PRcsf of 79ml/h±20SD (p<0.0001). Post-surgical CSF leak (n=26): PRcsf of 90ml/h±20SD (p<0.0001). Subarachnoid haemorrhage (n=34): PRcsf of 143ml/h±9SD (p<0.0001). Intracerebral haemorrhage (n=22): PRcsf of 137ml/h±20SD (p<0.0001). Spinal lesions (n=7): PRcsf of 130ml/h±20SD (p<0.0032). Pituitary adenomas (n=10): PRcsf of 29 ml/h±9SD (p<0.049). Idiopathic intracranial hypertension (n=15): PRcsf of 86ml/h±10SD (p<0.0001). Decompensated long-standing overt ventriculomegaly (n=4): PRcsf of 65ml/h±10SD (p<0.0001). Cerebral infection (n=5): PRcsf of 90ml/h±20SD (p<0.0001). CONCLUSION: Net CSF production rate may be higher than expected in many conditions, as measured with new device LiquoGuard7 through the study of net flow rate, which may have implications for clinical decisions on CSF diversion. The conventional understanding of CSF production and circulation does not explain the findings of this study. More extensive studies are needed to validate this technique.
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Hidrocefalia de Pressão Normal , Hidrocefalia , Hemorragia Subaracnóidea , Humanos , Hidrocefalia/cirurgia , Pressão do Líquido Cefalorraquidiano , Vazamento de Líquido Cefalorraquidiano , Estudos Prospectivos , Líquido CefalorraquidianoRESUMO
BACKGROUND: It is thought that the internal jugular veins (IJV) are the primary route for cranial venous outflow in supine position and the vertebral venous plexus when upright. Previous studies have noted a greater increase in intracranial pressure (ICP) when subjects turn their head in one direction compared to the other, but no clear cause had been investigated. We hypothesised that in the supine position, head turning and consequently obstructing the IJV draining the dominant transverse sinus (TVS) would lead to a greater rise in ICP compared to turning to the non-dominant side. METHODS: A prospective study in a large-volume neurosurgical centre. Patients undergoing continuous ICP monitoring as part of their standard clinical management were recruited. Immediate ICP was measured in different head positions (neutral, rotated to the right and left) when supine, seated, and standing. TVS dominance was established by consultant radiologist report on venous imaging. RESULTS: Twenty patients were included in the study, with a median age of 44 years. Venous system measurements revealed 85% right-sided vs 15% left-sided dominance. Immediate ICP rose more when head turning from neutral to the dominant TVS (21.93mmHg ± 4.39) vs non-dominant side (16.66mmHg ± 2.71) (p= <0.0001). There was no significant relationship in the sitting (6.08mmHg ± 3.86 vs 4.79mmHg ± 3.81, p = 0.13) or standing positions (8.74mmHg ± 4.30 vs 6.76mmHg ± 4.14, p =0.07). CONCLUSION: This study has provided further evidence that the transverse venous sinus to internal jugular system pathway is the likely primary venous drainage when supine; and quantified its effect when head turning on ICP. It may guide patient-specific nursing care and advice.
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Pressão Intracraniana , Postura , Humanos , Adulto , Movimentos da Cabeça , Estudos Prospectivos , Postura Sentada , Veias Jugulares/diagnóstico por imagemRESUMO
BACKGROUND: The commonly used cerebrospinal fluid (CSF) drainage system remains the manual drip-chamber drain. The LiquoGuard (Möller Medical GmbH, Germany) is an automated CSF management device with dual functionality, measuring intracranial pressure and automatic pressure- or volume-led CSF drainage. There is limited research for comparison of devices, particularly in the neurosurgical field, where it has potential to reshape care. OBJECTIVE: This study aims to compare manual drip-chamber drain versus LiquoGuard system, by assessing accuracy of drainage, associated morbidity and impact on length of stay. METHOD: Inclusion criteria consisted of suspected normal pressure hydrocephalus (NPH) patients undergoing extended lumbar drainage. Patients were divided into manual drain group versus automated group. RESULTS: Data was analysed from 42 patients: 31 in the manual group versus 11 in the LiquoGuard group. Volumetric over-drainage was seen in 90.3% (n = 28) versus 0% (p < 0.05), and under-drainage in 38.7% (n = 12) versus 0% (p < 0.05), in the manual and automatic group, respectively. Symptoms of over-drainage were noted in 54.8% (n = 17) of the manual group, all of which had episodes of volumetric over-drainage, versus 18.2% (n = 2) in automated group, of which neither had actual over-drainage (p < 0.05). Higher over-drainage symptoms of manual drain is likely due to increased fluctuation of CSF drainage, instead of smooth CSF drainage seen with LiquoGuard system. An increased length of stay was seen in 38.7% (n = 12) versus 9% (n = 1) (p < 0.05) in the manual and LiquoGuard group, respectively. CONCLUSION: The LiquoGuard device is a more superior way of CSF drainage in suspected NPH patients, with reduced morbidity and length of stay.
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Hidrocefalia de Pressão Normal , Humanos , Hidrocefalia de Pressão Normal/diagnóstico , Hidrocefalia de Pressão Normal/cirurgia , Hidrocefalia de Pressão Normal/líquido cefalorraquidiano , Pressão Intracraniana , Vazamento de Líquido Cefalorraquidiano , AlemanhaRESUMO
Introduction: There is no previous literature on the use of telemetric sensors (telesensor) in the lumbar theca. We aim to provide novel data on telemetric pressure monitoring of the lumbar theca via lumboperitoneal shunts. Research question: Primary outcome is telemetric sensor malfunction of lumboperitoneal shunt. The secondary outcome is post-operative complications. Materials and methods: A single centre retrospective case series of patients with telemetric sensor in LP shunt system, between 2015 and 2021, consisting of 5 patients. Review of indications for use, duration of function of telemetric sensor and associated complications. Results: There was no procedural complications of LP shunt insertion with telemetric sensor. The patient with highest body weight patient had retraction of distal tubing which required distal resiting 3 times. Four out of five patients had no complications. In all cases, telemetric sensor functioned satisfactorily with no dysfunction. The duration of documentation was 1-40 months. Pressure readings were satisfactorily carried out in variety of positions. Discussion and conclusion: This is the first report of telemetric sensor use in the lumbar theca. It can provide a valuable way of measuring cerebrospinal fluid pressures, particularly in patients avoiding cranial surgery. More research is indicated to assess what pressure values would mean clinically.
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After craniectomy, patients are generally advised to wear a helmet when mobilising to protect the unshielded brain from damage. However, there exists limited guidance regarding head protection for patients at rest and when being transferred or turned. Here, we emphasise the need for such protocols and utilise evidence from several sources to affirm our viewpoint. A literature search was first performed using MEDLINE and EMBASE, looking for published material relating to head protection for patients post-craniectomy during rest, transfer or turning. No articles were identified using a wide-ranging search strategy. Next, we surveyed and interviewed staff and patients from our neurosurgical centre to ascertain how often their craniectomy site was exposed to external pressure and the precautions taken to prevent this. 59% of patients admitted resting in contact with the craniectomy site, in agreement with the observations of 67% of staff. In 63% of these patients, this occurred on a daily basis and for some, was associated with symptoms suggestive of raised intracranial pressure. 44% of staff did not use a method to prevent craniectomy site contact while 65% utilised no additional precautions during transfer or turning. 63% of patients received no information about avoiding craniectomy site contact upon discharge, and almost all surveyed wished for resting head protection if it were available. We argue that pragmatic guidelines are needed and that our results support this perspective. As such, we offer a simple, practical protocol which can be adopted and iteratively improved as further evidence becomes available in this area.
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INTRODUCTION: Depending on severity of presentation, pituitary apoplexy can be managed with acute surgery or non-operatively. We aim to assess long-term tumour control, visual and endocrinological outcomes following pituitary apoplexy with special emphasis on patients treated non-operatively. METHODS: Multicentre retrospective cohort study. All patients with symptomatic pituitary apoplexy were included. Patients were divided into 3 groups: group 1: surgery within 7 days; group 2: surgery 7 days-3 months; group 3: non-operative. Further intervention for oncological reasons during follow-up was the primary outcome. Secondary outcome measures included visual and endocrinological function at last follow-up. RESULTS: One hundred sixty patients were identified with mean follow-up of 48 months (n = 61 group 1; n = 34 group 2; n = 64 group 3). Factors influencing decision for surgical treatment included visual acuity loss (OR: 2.50; 95% CI: 1.02-6.10), oculomotor nerve palsy (OR: 2.80; 95% CI: 1.08-7.25) and compression of chiasm on imaging (OR: 9.50; 95% CI: 2.06-43.73). Treatment for tumour progression/recurrence was required in 17%, 37% and 24% in groups 1, 2 and 3, respectively (p = 0.07). Urgent surgery (OR: 0.16; 95% CI: 0.04-0.59) and tumour regression on follow-up (OR: 0.04; 95% CI: 0.04-0.36) were independently associated with long-term tumour control. Visual and endocrinological outcomes were comparable between groups. CONCLUSION: Urgent surgery is an independent predictor of long-term tumour control following pituitary apoplexy. However, 76% of patients who successfully complete 3 months of non-operative treatment may not require any intervention in the long term.