Brain motion in patients with skull defects: B-mode ultrasound observations on respiration-induced movements

Recent Updates on Controversies in Decompressive Craniectomy and Cranioplasty: Physiological Effect, Indication, Complication, and Management

Decompressive craniectomy (DCE) and cranioplasty (CP) are surgical procedures used to manage elevated intracranial pressure (ICP) in various clinical scenarios, including ischemic stroke, hemorrhagic stroke, and traumatic brain injury. The physiological changes following DCE, such as cerebral blood flow, perfusion, brain tissue oxygenation, and autoregulation, are essential for understanding the benefits and limitations of these procedures. A comprehensive literature search was conducted to systematically review the recent updates in DCE and CP, focusing on the fundamentals of DCE for ICP reduction, indications for DCE, optimal sizes and timing for DCE and CP, the syndrome of trephined, and the debate on suboccipital CP. The review highlights the need for further research on hemodynamic and metabolic indicators following DCE, particularly in relation to the pressure reactivity index. It provides recommendations for early CP within three months of controlling increased ICP to facilitate neurological recovery. Additionally, the review emphasizes the importance of considering suboccipital CP in patients with persistent headaches, cerebrospinal fluid leakage, or cerebellar sag after suboccipital craniectomy. A better understanding of the physiological effects, indications, complications, and management strategies for DCE and CP to control elevated ICP will help optimize patient outcomes and improve the overall effectiveness of these procedures.

The compensatory mechanism and clinical significance of hydrocephalus after cranioplasty

Objective

Cranioplasty (CP) and ventriculoperitoneal shunt (VPS) are procedures required after decompression of the flap (DC) to protect the cranial frame and prevent hydrocephalus. This study evaluated the safety and efficacy of different surgical sequences of CP and VPS after DC and identified risk factors for necessary permanent VPS.

Methods

From January 2017 to December 2021, valid follow-up data were collected in 192 cases. The observation group preferred CP, and then evaluated whether to receive VPS according to the progress of hydrocephalus. the control group was prioritized for VPS and continued with CP after 1 week. The improvement of hydrocephalus symptoms, follow-up outcomes, and post-operative complications before and after surgery were compared between the two groups, and univariate analysis was used to determine the risk factors for necessary permanent risk factors for VPS.

Results

There were 86 cases (44.8%) in the observation group, who received CP first, while 106 cases (55.2%) in the control group received VPS and CP, respectively. There was no significant difference between the two groups according to Barthel index, FMAS, Mrs, GCS, and Evans index, and there was no statistical difference in complications between the two groups. However, in the observation group, hydrocephalus disappeared after CP operation in 29 cases (33.7%), and finally avoided VPS. Univariate analysis showed that the main etiology was related to the size of the skull defect, the distance of the talus margin relative to the flap to the midline, and lumbar puncture pressure was a predictor of the need for permanent VPS.

Conclusion

This study provides detailed information on the efficacy and complications of different sequences of preferential CP or VPS after DC surgery. We found that priority CP reduced the incidence of VPS surgery without affecting surgical outcomes and complications.

Hydrocephalus and the neuro-intensivist: CSF hydrodynamics at the bedside

Hydrocephalus (HCP) is far more complicated than a simple disorder of cerebrospinal fluid (CSF) circulation. HCP is a common complication in patients with subarachnoid hemorrhage (SAH) and after craniectomy. Clinical measurement in HCP is mainly related to intracranial pressure (ICP) and cerebral blood flow. The ability to obtain quantitative variables that describe CSF dynamics at the bedside before potential shunting may support clinical intuition with a description of CSF dysfunction and differentiation between normal pressure hydrocephalus and brain atrophy. This review discusses the advanced research on HCP and how CSF is generated, stored and absorbed within the context of a mathematical model developed by Marmarou. Then, we proceed to explain the main quantification analysis of CSF dynamics using infusion techniques for deciding on definitive treatment. We consider that such descriptions of multiple parameters of measurements need to be significantly appreciated by the caring neuro-intensivist, for better understanding of the complex pathophysiology and clinical management and finally, improve of the prognosis of these patients with HCP.

In this review article, we present current and novel theories of CSF circulation and pathophysiology of hydrocephalus, along with results from infusion studies for evaluating CSF dynamics at the bedside.

Neuroplastic Surgery Aboard USNS Comfort During the COVID-19 Pandemic in New York City

In December of 2019, a novel virus known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) produced a cluster of viral pneumonia cases in Wuhan, China. In the United States (US), New York City was particularly devastated, with the volume and acuity of patients placing an unprecedented strain on the hospital system and health care workers. In response to this crisis, USNS Comfort (T-AH 20) was deployed to New York City with a 1100 member medical team to augment local hospitals. Comfort's mission to New York City was dynamic, and required special adaptation to care for both COVID positive and COVID negative patients. Neuroplastic surgery procedures were indicated in both COVID positive and COVID negative patients, and lessons learned with regard to performance of complex surgery in an unfamiliar environment consisted of developing a thorough understanding of ones capabilities, and working with a highly skilled team of Navy surgeons, anesthesiologists, and surgical support staff, in order to provide high quality care in a deployment platform.

Subdural Fluid Collection After the Clipping of Unruptured Intracranial Aneurysms: Its Clinical Course and Significance

OBJECTIVE

We evaluated the clinical course and significance of postoperative subdural fluid collection (SFC) and identified the patients who were at risk of developing postoperative chronic subdural hematoma (CSDH) after the clipping of unruptured intracranial aneurysms (UIAs).

METHODS

Between January 2012 and June 2014, we retrospectively reviewed 298 patients with UIAs treated by microsurgical clipping. Among them, 257 patients were enrolled in the present study. Subdural lesions (SDLs) were defined as SFC at 1-month follow-up computed tomography (CT) and a CSDH at any time within 1 month after the clipping of UIAs. We examined the volume changes, Hounsfield unit (HU) values, and the end results of SFC in serial CT scans.

RESULTS

The incidence of postoperative CSDH that needed burr hole surgery was 2.5%. Changes in SFC volume that occurred within 1 week of surgery were a risk factor for the occurrence of SDL at the 1-month follow-up CT (odds ratio 34.039; P < 0.001). The corrected average HU value of SCF (cut-off value: 11.9, with a sensitivity of 83.3% and specificity of 73.7%) on postoperative day 7 was an independent risk factor for development of a CSDH at the 1-month follow-up CT (odds ratio 19.261; P = 0.003).

CONCLUSIONS

SDLs seen during 1-month follow-up may be associated with the occurrence of increased SFC volume within a week after the clipping of UIAs. The corrected average HU value of the SFC on postoperative day 7 was the only risk factor for the development of CSDHs at 1-month follow-up CT.

Cranioplasty After Severe Traumatic Brain Injury: Effects of Trauma and Patient Recovery on Cranioplasty Outcome

Background

In patients with severe traumatic brain injury (sTBI) treated with decompressive craniectomy (DC), factors affecting the success of later cranioplasty are poorly known.

Objective

We sought to investigate if injury- and treatment-related factors, and state of recovery could predict the risk of major complications in cranioplasty requiring implant removal, and how these complications affect the outcome.

Methods

A retrospective cohort of 40 patients with DC following sTBI and subsequent cranioplasty was studied. Non-injury-related factors were compared with a reference population of 115 patients with DC due to other conditions.

Results

Outcome assessed 1 day before cranioplasty did not predict major complications leading to implant removal. Successful cranioplasty was associated with better outcome, whereas a major complication attenuates patient recovery: in patients with favorable outcome assessed 1 year after cranioplasty, major complication rate was 7%, while in patients with unfavorable outcome the rate was 42% (p = 0.003). Of patients with traumatic subarachnoid hemorrhage (tSAH) on admission imaging 30% developed a major complication, while none of patients without tSAH had a major complication (p = 0.014). Other imaging findings, age, admission Glasgow Coma Scale, extracranial injuries, length of stay at intensive care unit, cranioplasty materials, and timing of cranioplasty were not associated with major complications.

Conclusion

A successful cranioplasty after sTBI and DC predicts favorable outcome 1 year after cranioplasty, while stage of recovery before cranioplasty does not predict cranioplasty success or failure. tSAH on admission imaging is a major risk factor for a major complication leading to implant removal.

Syndrome of the Trephined: A Systematic Review

BACKGROUND

Syndrome of the trephined (SoT) is a rare, important complication of a craniectomy characterized by neurological dysfunction that improves with cranioplasty. Its varied symptoms include motor, cognitive, and language deficits. Its exact characterization appears suboptimal, with differing approaches of evaluation. Accordingly, this topic is in great need of further investigation.

OBJECTIVE

To accurately describe SoT and explore methods of an objective diagnosis/evaluation.

METHODS

Electronic searches of PubMed, MEDLINE, Web of Knowledge, and PsycINFO databases used the key words "syndrome of the trephined" and "sinking skin flap." Non-English-language and duplicate articles were eliminated. Title and abstract reviews were selected for relevance. Full-text reviews were selected for articles providing individual characteristics of SoT patients.

RESULTS

This review identified that SoT most often occurs in male patients (60%) at 5.1 ± 10.8 months after craniectomy for neurotrauma (38%). The average reported craniectomy is 88.3 ± 34.4 cm and usually exists with a "sunken skin flap" (93%). Symptoms most commonly include motor, cognitive, and language deficits (57%, 41%, 28%, respectively), with improvement after cranioplasty within 3.8 ± 3.9 days. Functional independence with activities of daily living is achieved by 54.9% of patients after 2.9 ± 3.4 months of rehabilitation. However, evaluation of SoT is inconsistent, with only 53% of reports documenting objective studies.

DISCUSSION

SoT is a variable phenomenon associated with a prolonged time to cranioplasty. Due to current weaknesses in objectivity, we hypothesize that SoT is often underdiagnosed and recommend a multifaceted approach for consistent evaluation.

CONCLUSION

SoT is a serious complication that lacks exact characterization and deserves future investigation. Improved understanding and recognition have important implications for early intervention and patient outcomes.

ABBREVIATIONS

ADLs, activities of daily livingCBF, cerebral blood flowSoT, syndrome of the trephinedVP, ventriculoperitoneal.