Search Results

Object.

The purpose of this prospective study was to evaluate the cumulative incidence, duration, and time course of cerebral vasospasm after traumatic brain injury (TBI) in a cohort of 299 patients.

Methods.

Transcranial Doppler (TCD) ultrasonography studies of blood flow velocity in the middle cerebral and basilar arteries (V_MCA and V_BA, respectively) were performed at regular intervals during the first 2 weeks posttrauma in association with ¹³³Xe cerebral blood flow (CBF) measurements. According to current definitions of vasospasm, five different criteria were used to classify the patients: A (V_MCA > 120 cm/second); B (V_MCA > 120 cm/second and a Lindegaard ratio [LR] > 3); C (spasm index [SI] in the anterior circulation > 3.4); D (V_BA > 90 cm/second); and E (SI in the posterior circulation > 2.5). Criteria C and E were considered to represent hemodynamically significant vasospasm. Mixed-effects spline models were used to analyze the data of multiple measurements with an inconsistent sampling rate.

Overall 45.2% of the patients demonstrated at least one criterion for vasospasm. The patients in whom vasospasm developed were significantly younger and had lower Glasgow Coma Scale scores on admission. The normalized cumulative incidences were 36.9 and 36.2% for patients with Criteria A and B, respectively. Hemodynamically significant vasospasm in the anterior circulation (Criterion C) was found in 44.6% of the patients, whereas vasospasm in the BA—Criterion D or E—was found in only 19 and 22.5% of the patients, respectively. The most common day of onset for Criteria A, B, D, and E was postinjury Day 2. The highest risk of developing hemodynamically significant vasospasm in the anterior circulation was found on Day 3. The daily prevalence of vasospasm in patients in the intensive care unit was 30% from postinjury Day 2 to Day 13. Vasospasm resolved after a duration of 5 days in 50% of the patients with Criterion A or B and after a period of 3.5 days in 50% of those patients with Criterion D or E. Hemodynamically significant vasospasm in the anterior circulation resolved after 2.5 days in 50% of the patients. The time course of that vasospasm was primarily determined by a decrease in CBF.

Conclusions.

The incidence of vasospasm after TBI is similar to that following aneurysmal subarachnoid hemorrhage. Because vasospasm is a significant event in a high proportion of patients after severe head injury, close TCD and CBF monitoring is recommended for the treatment of such patients.

OBJECTIVE

Craniosynostosis is a premature cranial suture junction and requires a craniectomy to decrease cranial compression and remodel the affected areas of the skull. However, mastering these neurosurgical procedures requires many years of supervised training. The use of surgical simulation can reduce the risk of intraoperative error. The authors propose a new instrument for neurosurgical education, which mixes reality with virtual and realistic simulation for repair of craniosynostosis (scaphocephaly type).

METHODS

This study tested reality simulators with a synthetic thermo-retractile/thermosensitive rubber joined with different polymers. To validate the model, 18 experienced surgeons participated in this study using 3D videos developed using 3DS Max software. Renier’s “H” technique for craniosynostosis correction was applied during the simulation. All participants completed questionnaires to evaluate the simulator.

RESULTS

An expert surgical team approved the craniosynostosis reality and virtual simulators. More than 94% of participants found the simulator relevant, considering aspects such as weight, surgical positioning, dissection by planes, and cranial reconstruction. The consistency and material resistance were also approved on average by more than 60% of the surgeons.

CONCLUSIONS

The virtual simulator demands a high degree of effectiveness with 3D perception in anatomy and operative strategies in neurosurgical training. Physical and virtual simulation with mixed reality required psychomotor and cognitive abilities otherwise acquired only during practical surgical training with supervision.

Object

The use of decompressive craniectomy has experienced a revival in the previous decade, although its actual benefit on patients’ neurological outcome remains the subject of debate. A better understanding of the intracranial pressure dynamics, as well as of the metabolic and hemodynamic brain processes, may be useful in assessing the effect of this surgery on the pathophysiology of the swollen brain. The aim of this study was to use transcranial Doppler (TCD) ultrasonography to examine the hemodynamic changes in the brain after decompressive craniectomy in patients with head injury, in addition to examining the relationship between such hemodynamic changes and the patient’s neurological outcome.

Methods

Nineteen patients presenting with traumatic brain swelling and cerebral herniation syndrome who had undergone decompressive craniectomy with dural expansion were studied prospectively. The TCD ultrasonography measurements were performed bilaterally in both the middle cerebral artery (MCA) and in the distal portion of the cervical internal carotid artery (ICA) immediately prior to and after surgical decompression.

After surgery, the mean blood flow velocity (BFV) rose to 175 ± 209% of preoperative values in the MCA of the operated side, while rising to 132 ± 183% in the contralateral side; the difference between the mean BFV increase in in the MCA of both the decompressed and the opposite side reached statistical significance (p < 0.05). The mean BFV of the extracranial ICA increased to 91 ± 119% in the surgical side and 45 ± 60% in the opposite side. Conversely, the MCA pulsatility index (PI) values decreased, on average, to 33 ± 36% of the preoperative value in the operated side and to 30 ± 34% on the opposite side; the MCA PI value reductions were significantly greater in the decompressed side when compared with the contralateral side (p < 0.05). The PI of the extracranial ICA reduced, on average, to 37 ± 23% of the initial values in the operated side and to 24 ± 34%, contralaterally. No correlation was verified between the neurological outcome and cerebral hemodynamic changes seen on TCD ultrasonography.

Conclusions

Decompressive craniectomy results in a significant elevation of cerebral BFV in most patients with traumatic brain swelling and transtentorial herniation syndrome. The increase in cerebral BFV may also occur in the side opposite the decompressed hemisphere; the cerebral BFV increase is significantly greater in the operated hemisphere than contralaterally. Concomitantly, PI values decrease significantly postoperatively, mainly in the decompressed cerebral hemisphere, indicating reduction in cerebrovascular resistance.