Complications associated with early cranioplasty for patients with traumatic brain injury

J Neurosurg 137:776–781, 2022

Cranioplasty is a technically simple procedure, although one with potentially high rates of complications. The ideal timing of cranioplasty should minimize the risk of complications, but research investigating cranioplasty timing and risk of complications has generated diverse findings. Previous studies have included mixed populations of patients undergoing cranioplasty following decompression for traumatic, vascular, and other cerebral insults, making results challenging to interpret. The objective of the current study was to examine rates of complications associated with cranioplasty, specifically for patients with traumatic brain injury (TBI) receiving this procedure at the authors’ high-volume level 1 trauma center over a 25-year time period.

METHODS A single-institution retrospective review was conducted of patients undergoing cranioplasty after decompression for trauma. Patients were identified and clinical and demographic variables obtained from 2 neurotrauma databases. Patients were categorized into 3 groups based on timing of cranioplasty: early (≤ 90 days after craniectomy), intermediate (91–180 days after craniectomy), and late (> 180 days after craniectomy). In addition, a subgroup analysis of complications in patients with TBI associated with ultra-early cranioplasty (< 42 days, or 6 weeks, after craniectomy) was performed.

RESULTS Of 435 patients identified, 141 patients underwent early cranioplasty, 187 patients received intermediate cranioplasty, and 107 patients underwent late cranioplasty. A total of 54 patients underwent ultra-early cranioplasty. Among the total cohort, the mean rate of postoperative hydrocephalus was 2.8%, the rate of seizure was 4.6%, the rate of postoperative hematoma was 3.4%, and the rate of infection was 6.0%. The total complication rate for the entire population was 16.8%. There was no significant difference in complications between any of the 3 groups. No significant differences in postoperative complications were found comparing the ultra-early cranioplasty group with all other patients combined.

CONCLUSIONS In this cohort of patients with TBI, early cranioplasty, including ultra-early procedures, was not associated with higher rates of complications. Early cranioplasty may confer benefits such as shorter or fewer hospitalizations, decreased financial burden, and overall improved recovery, and should be considered based on patient-specific factors.

 

Blood Biomarkers and Structural Imaging Correlations Post-Traumatic Brain Injury: A Systematic Review

Neurosurgery 90:170–179, 2022

Blood biomarkers are of increasing importance in the diagnosis and assessment of traumatic brain injury (TBI). However, the relationship between them and lesions seen on imaging remains unclear.

OBJECTIVE: To perform a systematic review of the relationship between blood biomarkers and intracranial lesion types, intracranial lesion injury patterns, volume/number of intracranial lesions, and imaging classification systems.

METHODS: We searched Medical Literature Analysis and Retrieval System Online, Excerpta Medica dataBASE, and Cumulative Index to Nursing and Allied Health Literature from inception to May 2021, and the references of included studies were also screened. Heterogeneity in study design, biomarker types, imaging modalities, and analyses inhibited quantitative analysis, with a qualitative synthesis presented.

RESULTS: Fifty-nine papers were included assessing one or more biomarker to imaging comparisons per paper: 30 assessed imaging classifications or injury patterns, 28 assessed lesion type, and 11 assessed lesion volume or number. Biomarker concentrations were associated with the burden of brain injury, as assessed by increasing intracranial lesion volume, increasing numbers of traumatic intracranial lesions, and positive correlations with imaging classification scores. There were inconsistent findings associating different biomarkers with specific imaging phenotypes including diffuse axonal injury, cerebral edema, and intracranial hemorrhage.

CONCLUSION: Blood-based biomarker concentrations after TBI are consistently demonstrated to correlate burden of intracranial disease. The relation with specific injury types is unclear suggesting a lack of diagnostic specificity and/or is the result of the complex and heterogeneous nature of TBI.

External Lumbar Drainage following Traumatic Intracranial Hypertension

Neurosurgery 89:395–405, 2021

Traumatic brain injury (TBI) often results in elevations in intracranial pressure (ICP) that are refractory to standard therapies. Several studies have investigated the utility of external lumbar drainage (ELD) in this setting.

OBJECTIVE: To evaluate the safety and efficacy of ELD or lumbar puncture with regard to immediate effect on ICP, durability of the effect on ICP, complications, and neurological outcomes in adults with refractory traumatic intracranial hypertension.

METHODS: A systematic review and meta-analysis were conducted beginning with a comprehensive search of PubMed/EMBASE. Two investigators reviewed studies for eligibility and extracted data. The strength of evidence was evaluated using GRADE methodology. Random-effects meta-analyses were performed to calculate pooled estimates.

RESULTS: Nine articles detailing 6 studies (N = 110) were included. There was moderate evidence that ELD has a significant immediate effect on ICP; the pooled effect size was –19.5 mmHg (95% CI –21.0 to –17.9 mmHg). There was low evidence to indicate a durable effect of ELD on ICP up to at least 24 h following ELD. There was low evidence to indicate that ELD was safe and associated with a low rate of clinical cerebral herniation or meningitis. There was very low evidence pertaining to neurological outcomes.

CONCLUSION: Given preliminary data indicating potential safety and feasibility in highly selected cases, the use of ELD in adults with severe TBI and refractory intracranial hypertension in the presence of open basal cisterns and absence of large focal hematoma merits further high-quality investigation; the ideal conditions for potential application remain to be determined.

Complications of Cranioplasty in Relation to Material: Systematic Review, Network Meta-Analysis and Meta-Regression

Neurosurgery 89:383–394, 2021

Cranioplasty is a ubiquitous neurosurgical procedure consisting of reconstruction of a pre-existing calvarial defect. Many materials are available, including polymethylmethacrylate in hand-moulded (hPMMA) and prefabricated (pPMMA) form, hydroxyapatite (HA), polyetheretherketone (PEEK) and titanium (Ti). OBJECTIVE: To perform a networkmeta-analysis (NMA) to assess the relationship between materials and complications of cranioplasty.

METHODS: PubMed/MEDLINE, Google Scholar, EMBASE, Scopus, and The Cochrane Library were searched from January 1, 1990 to February 14, 2021. Studies detailing rates of any of infections, implant exposure, or revision surgery were included. A frequentist NMA was performed for each complication. Risk ratios (RRs) with 95% CIs were calculated for each material pair.

RESULTS: A total of 3620 abstractswere screened and 31 full paperswere included. Surgical revision was reported in 18 studies and occurred in 316/2032 cases (14%; 95% CI 11-17). PEEK had the lowest risk of re-operation with a rate of 8/157 (5%; 95% CI 0-11) in 5 studies, superior to autografts (RR 0.20; 95% CI 0.07-0.57), hPMMA (RR 0.20; 95% CI 0.07-0.60), Ti (RR 0.39; 95% CI 0.17-0.92), and pPMMA (RR 0.14; 95% CI 0.04-0.51). Revision rate was 131/684 (19%; 95% CI 13-25; 10 studies) in autografts, 61/317 (18%; 95%CI 9-28; 7 studies) in hPMMA, 84/599 (13%; 95% CI 7-19; 11 studies) in Ti, 7/59 (9%; 95% CI 1-23; 3 studies) in pPMMA, and 25/216 (12%; 95%CI 4-24; 4 studies) in HA. Infection occurred in 463/4667 (8%; 95%CI 6-11) and implant exposure in 120/1651 (6%; 95% CI 4-9).

CONCLUSION: PEEK appears to have the lowest risk of cranioplasty revision, but further research is required to determine the optimal material.

Guidelines for the Management of Severe Traumatic Brain Injury: 2020 Update of the Decompressive Craniectomy Recommendations

Neurosurgery 87:427–434, 2020

When the fourth edition of the Brain Trauma Foundation’s Guidelines for theManagement of Severe Traumatic Brain Injury were finalized in late 2016, it was known that the results of the RESCUEicp (Trial of Decompressive Craniectomy for Traumatic Intracranial Hypertension) randomized controlled trial of decompressive craniectomy would be public after the guidelines were released.

The guideline authors decided to proceed with publication but to update the decompressive craniectomy recommendations later in the spirit of “living guidelines,” whereby topics are updated more frequently, and between new editions, when important new evidence is published.

The update to the decompressive craniectomy chapter presented here integrates the findings of the RESCUEicp study as well as the recently published 12-mo outcome data from the DECRA (Decompressive Craniectomy in Patients With Severe Traumatic Brain Injury) trial. Incorporation of these publications into the body of evidence led to the generation of 3 new level-IIA recommendations; a fourth previously presented level-IIA recommendation remains valid and has been restated. To increase the utility of the recommendations, we added a new section entitled Incorporating the Evidence into Practice.

This summary of expert opinion provides important context and addresses key issues for practitioners, which are intended to help the clinician utilize the available evidence and these recommendations. The full guideline canbe found at: https://braintrauma.org/guidelines/guidelines-for-themanagement- of-severe-tbi-4th-ed#/.

Effect of decompressive craniectomy in the postoperative expansion of traumatic intracerebral hemorrhage: a propensity score–based analysis

J Neurosurg 132:1623–1635, 2020

Traumatic intracerebral hemorrhage (TICH) represents approximately 13%–48% of the lesions after a traumatic brain injury (TBI), and hemorrhagic progression (HP) occurs in 38%–63% of cases. In previous studies, decompressive craniectomy (DC) has been characterized as a risk factor in the HP of TICH; however, few studies have focused exclusively on this relationship. The object of the present study was to analyze the relationship between DC and the growth of TICH and to reveal any correlation with the size of the craniectomy, degree of cerebral parenchymal herniation (CPH), or volumetric expansion of the TICH.

METHODS The authors retrospectively analyzed the records of 497 adult patients who had been consecutively admitted after suffering a severe or moderate closed TBI. An inclusion criterion was presentation with one or more TICHs on the initial or control CT. Demographic, clinical, radiological, and treatment variables were assessed for associations.

RESULTS Two hundred three patients presenting with 401 individual TICHs met the selection criteria. TICH growth was observed in 281 cases (70.1%). Eighty-two cases (20.4%) underwent craniectomy without TICH evacuation. In the craniectomy group, HP was observed in 71 cases (86.6%); in the noncraniectomy group (319 cases), HP occurred in 210 cases (65.8%). The difference in the incidence of HP between the two groups was statistically significant (OR 3.41, p < 0.01). The mean area of the craniectomy was 104.94 ± 27.5 cm2, and the mean CPH distance through the craniectomy was 17.85 ± 11.1 mm. The mean increase in the TICH volume was greater in the groups with a craniectomy area > 115 cm2 and CPH > 25 mm (16.12 and 14.47 cm3, respectively, p = 0.01 and 0.02). After calculating the propensity score (PS), the authors followed three statistical methods—matching, stratification, and inverse probability treatment weighting (IPTW)—thereby obtaining an adequate balance of the covariates. A statistically significant relationship was found between HP and craniectomy (OR 2.77, p = 0.004). This correlation was confirmed with the three methodologies based on the PS with odds greater than 2.

CONCLUSIONS DC is a risk factor for the growth of TICH, and there is also an association between the size of the DC and the magnitude of the volume increase in the TICH.

 

Implementation of cisternostomy as adjuvant to decompressive craniectomy for the management of severe brain trauma

Acta Neurochirurgica (2020) 162:469–479

Objective To evaluate the value of an adjuvant cisternostomy (AC) to decompressive craniectomy (DC) for the management of patients with severe traumatic brain injury (sTBI).

Methods A single-center retrospective quality control analysis of a consecutive series of sTBI patients surgically treated with AC or DC alone between 2013 and 2018. A subgroup analysis, “primary procedure” and “secondary procedure”, was also performed. We examined the impact of AC vs. DC on clinical outcome, including long-term (6 months) extended Glasgow outcome scale (GOS-E), the duration of postoperative ventilation, and intensive care unit (ICU) stay, mortality, Glasgow coma scale at discharge, and time to cranioplasty. We also evaluated and analyzed the impact of AC vs. DC on post-procedural intracranial pressure (ICP) and brain tissue oxygen (PbO2) values as well as the need for additional osmotherapy and CSF drainage.

Results Forty patients were examined, 22 patients in the DC group, and 18 in the AC group. Compared with DC alone, AC was associated with significant shorter duration of mechanical ventilation and ICU stay, as well as better Glasgow coma scale at discharge. Mortality rate was similar. At 6-month, the proportion of patients with favorable outcome (GOS-E ≥ 5) was higher in patients with AC vs. DC [10/18 patients (61%) vs. 7/20 (35%)]. The outcome difference was particularly relevant when AC was performed as primary procedure (61.5% vs. 18.2%; p = 0.04). Patients in the AC group also had significant lower average postsurgical ICP values, higher PbO2 values and required less osmotic treatments as compared with those treated with DC alone.

Conclusion Our preliminary single-center retrospective data indicate that AC may be beneficial for the management of severe TBI and is associated with better clinical outcome. These promising results need further confirmation by larger multicenter clinical studies. The potential benefits of cisternostomy should not encourage its universal implementation across trauma care centers by surgeons that do not have the expertise and instrumentation necessary for cisternal microsurgery. Training in skull base and vascular surgery techniques for trauma care surgeons would avoid the potential complications associated with this delicate procedure.

Twenty-Five Years of Intracranial Pressure Monitoring After Severe Traumatic Brain Injury: A Retrospective, Single-Center Analysis

Neurosurgery, Volume 85, Issue 1, July 2019, Pages E75–E82

Intracranial pressure (ICP) is a clinically important variable after severe traumatic brain injury (TBI) and has been monitored, along with clinical outcome, for over 25 yr in Addenbrooke’s hospital, Cambridge, United Kingdom. This time period has also seen changes in management strategies with the implementation of protocolled specialist neurocritical care, expansion of neuromonitoring techniques, and adjustments of clinical treatment targets.

OBJECTIVE: To describe the changes in intracranial monitoring variables over the past 25 yr.

METHODS: Data from 1146 TBI patients requiring ICP monitoring were analyzed. Monitored variables included ICP, cerebral perfusion pressure (CPP), and the cerebral pressure reactivity index (PRx). Data were stratified into 5-yr epochs spanning the 25 yr from 1992 to 2017.

RESULTS: CPP increased sharply with specialist neurocritical care management (P < 0.0001) (introduction of a specific TBI management algorithm) before stabilizing from 2000 onwards. ICP decreased significantly over the 25 yr of monitoring from an average of 19 to 12 mmHg (P < 0.0001) but PRx remained unchanged. The mean number of ICP plateau waves and the number of patients developing refractory intracranial hypertension both decreased significantly. Mortality did not significantly change in the cohort (22%).

CONCLUSION: We demonstrate the evolving trends in neurophysiological monitoring over the past 25 yr from a single, academic neurocritical care unit. ICP and CPP were responsive to the introduction of an ICP/CPP protocol while PRx has remained unchanged.

Randomized controlled study comparing 2 surgical techniques for decompressive craniectomy: with watertight duraplasty and without watertight duraplasty

J Neurosurg 129:1017–1023, 2018

Decompressive craniectomy (DC) is a widely used procedure in neurosurgery; however, few studies focus on the best surgical technique for the procedure. The authors’ objective was to conduct a prospective randomized controlled trial comparing 2 techniques for performing DC: with watertight duraplasty and without watertight duraplasty (rapid-closure DC).

METHODS The study population comprised patients ranging in age from 18 to 60 years who were admitted to the Neurotrauma Service of the Hospital da Restauração with a clinical indication for unilateral decompressive craniectomy. Patients were randomized by numbered envelopes into 2 groups: with watertight duraplasty (control group) and without watertight duraplasty (test group). After unilateral DC was completed, watertight duraplasty was performed in the control group, while in the test group, no watertight duraplasty was performed and the exposed parenchyma was covered with Surgicel and the remaining dura mater. Patients were then monitored daily from the date of surgery until hospital discharge or death. The primary end point was the incidence of surgical complications (CSF leak, wound infection, brain abscess, or subgaleal fluid collections). The following were analyzed as secondary end points: clinical outcome (analyzed using the Glasgow Outcome Scale [GOS]), surgical time, and hospital costs.

RESULTS Fifty-eight patients were enrolled, 29 in each group. Three patients were excluded, leaving 27 in the test group and 28 in the control group. There were no significant differences between groups regarding age, Glasgow Coma Scale score at the time of surgery, GOS score, and number of postoperative follow-up days. There were 9 surgical complications (5 in the control group and 4 in the test group), with no significant differences between the groups. The mean surgical time in the control group was 132 minutes, while in the test group the average surgical time was 101 minutes, a difference of 31 minutes (p = 0.001). The mean reduction in total cost was $420.00 USD (a 23.4% reduction) per procedure in the test group.

CONCLUSIONS Rapid-closure DC without watertight duraplasty is a safe procedure. It is not associated with a higher incidence of surgical complications (CSF leak, wound infection, brain abscess, or subgaleal fluid collections), and it decreased surgical time by 31 minutes on average. There was also a hospital cost reduction of $420.00 USD (23.4% reduction) per procedure. Clinical trial registration no.: NCT02594137 (clinicaltrials.gov)

 

Evaluation of a novel noninvasive ICP monitoring device in patients undergoing invasive ICP monitoring: preliminary results

J Neurosurg 128:1653–1660, 2018

There is no established method of noninvasive intracranial pressure (NI-ICP) monitoring that can serve as an alternative to the gold standards of invasive monitoring with external ventricular drainage or intraparenchymal monitoring. In this study a new method of NI-ICP monitoring performed using algorithms to determine ICP based on acoustic properties of the brain was applied in patients undergoing invasive ICP (I-ICP) monitoring, and the results were analyzed.

METHODS In patients with traumatic brain injury and subarachnoid hemorrhage who were undergoing treatment in a neurocritical intensive care unit, the authors recorded ICP using the gold standard method of invasive external ventricular drainage or intraparenchymal monitoring. In addition, the authors simultaneously measured the ICP noninvasively with a device (the HS-1000) that uses advanced signal analysis algorithms for acoustic signals propagating through the cranium. To assess the accuracy of the NI-ICP method, data obtained using both I-ICP and NI-ICP monitoring methods were analyzed with MATLAB to determine the statistical significance of the differences between the ICP measurements obtained using NI-ICP and I-ICP monitoring.

RESULTS Data were collected in 14 patients, yielding 2543 data points of continuous parallel ICP values in recordings obtained from I-ICP and NI-ICP. Each of the 2 methods yielded the same number of data points. For measurements at the ≥ 17–mm Hg cutoff, which was arbitrarily chosen for this preliminary analysis, the sensitivity and specificity for the NI-ICP monitoring were found to be 0.7541 and 0.8887, respectively. Linear regression analysis indicated that there was a strong positive relationship between the measurements. Differential pressure between NI-ICP and I-ICP was within ± 3 mm Hg in 63% of data-paired readings and within ± 5 mm Hg in 85% of data-paired readings. The receiver operating characteristic–area under the curve analysis revealed that the area under the curve was 0.895, corresponding to the overall performance of NI-ICP monitoring in comparison with I-ICP monitoring.

CONCLUSIONS This study provides the first clinical data on the accuracy of the HS-1000 NI-ICP monitor, which uses advanced signal analysis algorithms to evaluate properties of acoustic signals traveling through the brain in patients undergoing I-ICP monitoring. The findings of this study highlight the capability of this NI-ICP device to accurately measure ICP noninvasively. Further studies should focus on clinical validation for elevated ICP values.

Prognostic value of corpus callosum injuries in severe head trauma

Acta Neurochir (2017) 159:25–32

This study was performed to investigate the relationship between corpus callosum (CC) injury and prognosis in traumatic axonal injury (TAI).

Method: We retrospectively reviewed 264 patients with severe head trauma who underwent a conventional MR imaging in the first 60 days after injury. They were selected from a prospectively collected database of 1048 patients with severe head trauma admitted in our hospital. TAI lesions were defined as areas of increased signal intensity on T2 and FLAIR or areas of decreased signal on gradient-echo T2. We attempted to determine whether any MR imaging findings of TAI lesions at CC could be related to prognosis. Neurological impairment was assessed at 1 year after injury by means of GOS-E (good outcome being GOS-E 4/5 and bad outcome being GOS-E <4). We adjusted the multivariable analysis for the prognostic factors according to the IMPACT studies: the Core model (age, motor score at admission, and pupillary reactivity) and the Extended model (including CT information and second insults).

Results: We found 97 patients (37 %) with TAI at CC and 167 patients (63 %) without CC lesions at MR. A total of 62 % of the patients with CC lesions had poor outcome, whereas 38 % showed good prognosis. The presence of TAI lesions at the corpus callosum was associated with poor outcome 1 year after brain trauma (p < 0.001, OR 3.8, 95 % CI: 2.04–7.06). The volume of CC lesions measured on T2 and FLAIR se- quences was negatively correlated with the GOS-E after ad- justment for independent prognostic factors (p = 0.01, OR 2.23, 95 % CI:1.17–4.26). Also the presence of lesions at splenium was statistically related to worse prognosis (p = 0.002, OR 8.1, 95 % CI: 2.2–29.82). We did not find statistical significance in outcome between hemorrhagic and non-hemorrhagic CC lesions.

Conclusions: The presence of CC is associated with a poor outcome. The total volume of the CC lesion is an independent prognostic factor for poor outcome in severe head trauma.

Diffusion Tensor Imaging: A Possible Biomarker in Severe Traumatic Brain Injury and Aneurysmal Subarachnoid Hemorrhage?

diffusion-tensor-imaging-a-possible-biomarker-in-severe-traumatic-brain-injury-and-aneurysmal-subarachnoid-hemorrhage

Neurosurgery 79:786–793, 2016

A great need exists in traumatic brain injury (TBI) and aneurysmal subarachnoid hemorrhage (aSAH) for objective biomarkers to better characterize the disease process and to serve as early endpoints in clinical studies. Diffusion tensor imaging (DTI) has shown promise in TBI, but much less is known about aSAH.

OBJECTIVE: To explore the use of whole-brain DTI tractography in TBI and aSAH as a biomarker and early endpoint.

METHODS: Of a cohort of 43 patients with severe TBI (n = 20) or aSAH (n = 23) enrolled in a prospective, observational, multimodality monitoring study, DTI data were acquired at approximately day 12 (median, 12 days; interquartile range, 12-14 days) after injury in 22 patients (TBI, n = 12; aSAH, n = 10). Whole-brain DTI tractography was performed, and the following parameters quantified: average fractional anisotropy, mean diffusivity, tract length, and the total number of reconstructed fiber tracts. These were compared between TBI and aSAH patients and correlated with mortality and functional outcome assessed at 6 months by the Glasgow Outcome Scale Extended.

RESULTS: Significant differences were found for fractional anisotropy values (P = .01), total number of tracts (P = .03), and average tract length (P = .002) between survivors and nonsurvivors. A sensitivity analysis showed consistency of results between the TBI and aSAH patients for the various DTI measures.

CONCLUSION: DTI parameters, assessed at approximately day 12 after injury, correlated with mortality at 6 months in patients with severe TBI or aSAH. Similar patterns were found for both TBI and aSAH patients. This supports a potential role of DTI as early endpoint for clinical studies and a predictor of late mortality.

Improved Function After Deep Brain Stimulation for Chronic, Severe Traumatic Brain Injury

Improved Function After Deep Brain Stimulation for Chronic, Severe Traumatic Brain Injury

Neurosurgery 79:204–211, 2016

Severe traumatic brain injury (TBI) damages the frontal lobes and connecting networks, which impairs executive functions, including the ability to selfregulate. Despite significant disabling effects, there are few treatment options in the chronic phase after injury.

OBJECTIVE: To investigate the safety and potential effectiveness of deep brain stimulation (DBS) for individuals with chronic, disabling TBI and problems of behavioral and emotional self-regulation.

METHODS: This study was an open-label, prospective design with serial assessments of behavioral outcomes and positron emission tomography 2 years after DBS implantation. Four participants 6 to 21 years after severe TBIs from automobile crashes were included. Although alert and volitional, all experienced significant executive impairments, including either impulsivity or reduced initiation. DBS implants were placed bilaterally in the nucleus accumbens and anterior limb of the internal capsule to modulate the prefrontal cortex.

RESULTS: The procedure was safe, and all participants had improved functional outcomes. Two years after implantation, 3 met a priori criteria for improvement on the Mayo-Portland Adaptability Inventory-4. Improvement was due largely to better emotional adjustment, although 1 participant showed marked increases in multiple domains. Significant improvement in a composite score of functional capacity indicated improved independence in self-care and activities of daily living. The pattern of change in cognition corresponded with changes in activation of the prefrontal cortex observed in serial scanning.

CONCLUSION: This first study of DBS to this target for severe TBI supports its safety and suggests potential effectiveness to improve function years after injury. The primary impact was on behavioral and emotional adjustment, which in turn improved functional independence.

Graph theory, complex networks, and neurosurgery

Graph theory analysis of complex brain networks

J Neurosurg 124:1665–1678, 2016

Neuroanatomy has entered a new era, culminating in the search for the connectome, otherwise known as the brain’s wiring diagram. While this approach has led to landmark discoveries in neuroscience, potential neurosurgical applications and collaborations have been lagging.

In this article, the authors describe the ideas and concepts behind the connectome and its analysis with graph theory. Following this they then describe how to form a connectome using resting state functional MRI data as an example. Next they highlight selected insights into healthy brain function that have been derived from connectome analysis and illustrate how studies into normal development, cognitive function, and the effects of synthetic lesioning can be relevant to neurosurgery.

Finally, they provide a précis of early applications of the connectome and related techniques to traumatic brain injury, functional neurosurgery, and neurooncology.

Rotterdam ct scores before decompressive craniectomy

CT score TBI

J Neurosurg 124:1640–1645, 2016

Rotterdam CT scoring is a CT classification system for grouping patients with traumatic brain injury (TBI) based on multiple CT characteristics. This retrospective study aimed to determine the relationship between initial or preoperative Rotterdam CT scores and TBI prognosis after decompressive craniectomy (DC).

Methods: The authors retrospectively reviewed the medical records of all consecutive patients who underwent DC for nonpenetrating TBI in 2 hospitals from January 2006 through December 2013. Univariate and multivariate logistic regression and receiver operating characteristic (ROC) curve analyses were used to determine the relationship between initial or preoperative Rotterdam CT scores and mortality at 30 days or Glasgow Outcome Scale (GOS) scores at least 3 months after the time of injury. Unfavorable outcomes were GOS Scores 1–3 and favorable outcomes were GOS Scores 4 and 5.

Results: A total of 48 cases involving patients who underwent DC for TBI were included in this study. Univariate analyses showed that initial Rotterdam CT scores were significantly associated with mortality and both initial and preoperative Rotterdam CT scores were significantly associated with unfavorable outcomes. Multivariable logistic regression analysis adjusted for established predictors of TBI outcomes showed that initial Rotterdam CT scores were significantly associated with mortality (OR 4.98, 95% CI 1.40–17.78, p = 0.01) and unfavorable outcomes (OR 3.66, 95% CI 1.29–10.39, p = 0.02) and preoperative Rotterdam CT scores were significantly associated with unfavorable outcomes (OR 15.29, 95% CI 2.50–93.53, p = 0.003). ROC curve analyses showed cutoff values for the initial Rotterdam CT score of 5.5 (area under the curve [AUC] 0.74, 95% CI 0.59–0.90, p = 0.009, sensitivity 50.0%, and specificity 88.2%) for mortality and 4.5 (AUC 0.71, 95% CI 0.56–0.86, p = 0.02, sensitivity 62.5%, and specificity 75.0%) for an unfavorable outcome and a cutoff value for the preoperative Rotterdam CT score of 4.5 (AUC 0.81, 95% CI 0.69–0.94, p < 0.001, sensitivity 90.6%, and specificity 56.2%) for an unfavorable outcome.

Conclusions: Assessment of changes in Rotterdam CT scores over time may serve as a prognostic indicator in TBI and can help determine which patients require DC.

Is Intracranial Pressure Monitoring of Patients With Diffuse Traumatic Brain Injury Valuable?

ICP

Neurosurgery 78:361–369, 2016

Although intracranial pressure (ICP) monitoring of patients with severe traumatic brain injury (TBI) is recommended by the Brain Trauma Foundation, any benefits remain controversial.

OBJECTIVE: To evaluate the effects of ICP monitoring on the mortality of and functional outcomes in patients with severe diffuse TBI.

METHODS: Data were collected on patients with severe diffuse TBI (Glasgow Coma Scale [GCS] score on admission ,9 and Marshall Class II-IV) treated from January 2012 to December 2013 in 24 hospitals (17 level I trauma centers and 7 level II trauma centers) in 9 Chinese provinces. We evaluated the impact of ICP monitoring on 6-month mortality and favorable outcome using propensity score–matched analysis after controlling for independent predictors of these outcomes.

RESULTS: ICP monitors were inserted into 287 patients (59.5%). After propensity score matching, ICP monitoring significantly decreased 6-month mortality. ICP monitoring also had a greater impact on the most severely injured patients on the basis of head computed tomography data (Marshall computed tomography classification IV) and on patients with the lowest level of consciousness (GCS scores 3-5). After propensity score matching, monitoring remained nonassociated with a 6-month favorable outcome for the overall sample. However, monitoring had a significant impact on the 6-month favorable outcomes of patients with the lowest level of consciousness (GCS scores 3-5).

CONCLUSION: ICP monitor placement was associated with a significant decrease in 6-month mortality after adjustment for the baseline risk profile and the monitoring propensity of patients with diffuse severe TBI, especially those with GCS scores of 3 to 5 or of Marshall computed tomography classification IV.

Aspirin is associated with an increased risk of subdural hematoma in normal-pressure hydrocephalus patients following shunt implantation

Subdural Hematoma

J Neurosurg 123:423–426, 2015

In this paper the authors investigate whether shunt-treated patients with normal-pressure hydrocephalus receiving aspirin therapy are at increased risk of developing subdural hematoma (SDH).

Methods Records from 80 consecutive patients who had undergone implantation of a cerebrospinal fluid shunt for the treatment of normal-pressure hydrocephalus were retrospectively reviewed.

Results Eleven cases of symptomatic SDH occurred, all among patients receiving aspirin or clopidogrel. The 5-year survival estimate was 0.3 (p < 0.0001) for users of aspirin and the hazard ratio was 12.8 (95% CI 3.1–53).

Conclusions Patients on an aspirin therapy regimen have a markedly increased risk of SDH after a shunt has been implanted for the treatment of normal-pressure hydrocephalus. Users of clopidogrel may have an even greater risk.

Bur hole craniostomy for chronic subdural hematoma

Bur hole craniostomy for chronic subdural hematoma

J Neurosurg 123:65–74, 2015

There is inconsistency among the perioperative management strategies currently used for chronic subdural hematoma (cSDH). Moreover, postoperative complications such as acute intracranial bleeding and cSDH recurrence affect clinical outcome of cSDH surgery. This study evaluated the risk factors associated with acute intracranial bleeding and cSDH recurrence and identified an effective perioperative strategy for cSDH patients.

Methods A retrospective study of patients who underwent bur hole craniostomy for cSDH between 2008 and 2012 was performed.

Results A consecutive series of 303 cSDH patients (234 males and 69 females; mean age 67.17 years) was analyzed. Postoperative acute intracranial bleeding developed in 14 patients (4.57%) within a mean of 3.07 days and recurrence was observed in 37 patients (12.21%) within a mean of 31.69 days (range 10–104 days) after initial bur hole craniostomy. The comorbidities of hematological disease and prior shunt surgery were clinical factors associated with acute bleeding. There was a significant risk of recurrence in patients with diabetes mellitus, but recurrence did not affect the final neurological outcome (p = 0.776). Surgical details, including the number of operative bur holes, saline irrigation of the hematoma cavity, use of a drain, and type of postoperative ambulation, were not significantly associated with outcome. However, a large amount of drainage was associated with postoperative acute bleeding.

Conclusions Bur hole craniostomy is an effective surgical procedure for initial and recurrent cSDH. Patients with hematological disease or a history of prior shunt surgery are at risk for postoperative acute bleeding; therefore, these patients should be carefully monitored to avoid overdrainage. Surgeons should consider informing patients with diabetes mellitus that this comorbidity is associated with an increased likelihood of recurrence.

Traumatic Brain Injuries: The Influence of the Direction of Impact

Traumatic Brain Injuries- The Influence of the Direction of Impact

Neurosurgery 76:81–91, 2015

Head impact direction has been identified as an influential risk factor in the risk of traumatic brain injury (TBI) from animal and anatomic research; however, to date, there has been little investigation into this relationship in human subjects. If a susceptibility to certain types of TBI based on impact direction was found to exist in humans, it would aid in clinical diagnoses as well as prevention methods for these types of injuries.

OBJECTIVE: To examine the influence of impact direction on the presence of TBI lesions, specifically, subdural hematomas, subarachnoid hemorrhage, and parenchymal contusions.

METHODS: Twenty reconstructions of falls that resulted in a TBI were conducted in a laboratory based on eyewitness, interview, and medical reports. The reconstructions involved impacts to a Hybrid III anthropometric dummy and finite element modeling of the human head to evaluate the brain stresses and strains for each TBI event.

RESULTS: The results showed that it is likely that increased risk of incurring a subdural hematoma exists from impacts to the frontal or occipital regions, and parenchymal contusions from impacts to the side of the head. There was no definitive link between impact direction and subarachnoid hemorrhage. In addition, the results indicate that there is a continuum of stresses and strain magnitudes between lesion types when impact location is isolated, with subdural hematoma occurring at lower magnitudes for frontal and occipital region impacts, and contusions lower for impacts to the side.

CONCLUSION: This hospital data set suggests that there is an effect that impact direction has on TBI depending on the anatomy involved for each particular lesion.

Relevance of early head CT scans following neurosurgical procedures

early CT postcranio

J Neurosurg 121:307–312, 2014

Early postoperative head CT scanning is routinely performed following intracranial procedures for detection of complications, but its real value remains uncertain: so-called abnormal results are frequently found, but active, emergency intervention based on these findings may be rare. The authors’ objective was to analyze whether early postoperative CT scans led to emergency surgical interventions and if the results of neurological examination predicted this occurrence.

Methods. The authors retrospectively analyzed 892 intracranial procedures followed by an early postoperative CT scan performed over a 1-year period at Rush University Medical Center and classified these cases according to postoperative neurological status: baseline, predicted neurological change, unexpected neurological change, and sedated or comatose. The interpretation of CT results was reviewed and unexpected CT findings were classified based on immediate action taken: Type I, additional observation and CT; Type II, active nonsurgical intervention; and Type III, surgical intervention. Results were compared between neurological examination groups with the Fisher exact test.

Results. Patients with unexpected neurological changes or in the sedated or comatose group had significantly more unexpected findings on the postoperative CT (p < 0.001; OR 19.2 and 2.3, respectively) and Type II/III interventions (p < 0.001) than patients at baseline. Patients at baseline or with expected neurological changes still had a rate of Type II/III changes in the 2.2%–2.4% range; however, no patient required an immediate return to the operating room.

Conclusions. Over a 1-year period in an academic neurosurgery service, no patient who was neurologically intact or who had a predicted neurological change required an immediate return to the operating room based on early postoperative CT findings. Obtaining early CT scans should not be a priority in these patients and may even be cancelled in favor of MRI studies, if the latter have already been planned and can be performed safely and in a timely manner. Early postoperative CT scanning does not assure an uneventful course, nor should it replace accurate and frequent neurological checks, because operative interventions were always decided in conjunction with the neurological examination.