From decompressive craniectomy to cranioplasty and beyond-a pediatric neurosurgery perspective

Decompressive craniotomy in split-technique (DCST) for TBI in infants: introducing a new surgical technique to prevent long-term complications

INTRODUCTION

Decompressive craniectomy (DC) is rarely required in infants. These youngest patients are vulnerable to blood loss, and cranial reconstruction can be challenging due to skull growth and bone flap resorption. On the other hand, infants have thin and flexible bone and osteogenic potential. MATERIAL AND METHODS: We propose a new technique called DCST, which makes use of these unique aspects by achieving decompression using the circumstance of the thin and flexible bone. We describe the surgical technique and the follow-up course over a period of 13 months.

RESULTS AND CONCLUSION

In our study, DCST achieved adequate decompression and no  further repeated surgeries in accordance with decompressive craniectomy were needed afterwards.

Risk Factor Analysis of Cryopreserved Autologous Bone Flap Resorption in Adult Patients Undergoing Cranioplasty with Volumetry Measurement Using Conventional Statistics and Machine-Learning Technique

OBJECTIVE

Decompressive craniectomy (DC) with duroplasty is one of the common surgical treatments for life-threatening increased intracranial pressure (ICP). Once ICP is controlled, cranioplasty (CP) with reinsertion of the cryopreserved autologous bone flap or a synthetic implant is considered for protection and esthetics. Although with the risk of autologous bone flap resorption (BFR), cryopreserved autologous bone flap for CP is one of the important material due to its cost effectiveness. In this article, we performed conventional statistical analysis and the machine learning technique understand the risk factors for BFR.

METHODS

Patients aged >18 years who underwent autologous bone CP between January 2015 and December 2021 were reviewed. Demographic data, medical records, and volumetric measurements of the autologous bone flap volume from 94 patients were collected. BFR was defined with absolute quantitative method (BFR-A) and relative quantitative method (BFR%). Conventional statistical analysis and random forest with hyper-ensemble approach (RF with HEA) was performed. And overlapped partial dependence plots (PDP) were generated.

RESULTS

Conventional statistical analysis showed that only the initial autologous bone flap volume was statistically significant on BFR-A. RF with HEA showed that the initial autologous bone flap volume, interval between DC and CP, and bone quality were the factors with most contribution to BFR-A, while, trauma, bone quality, and initial autologous bone flap volume were the factors with most contribution to BFR%. Overlapped PDPs of the initial autologous bone flap volume on the BRF-A crossed at approximately 60 mL, and a relatively clear separation was found between the non-BFR and BFR groups. Therefore, the initial autologous bone flap of over 60 mL could be a possible risk factor for BFR.

CONCLUSION

From the present study, BFR in patients who underwent CP with autologous bone flap might be inevitable. However, the degree of BFR may differ from one to another. Therefore, considering artificial bone flaps as implants for patients with large DC could be reasonable. Still, the risk factors for BFR are not clearly understood. Therefore, chronological analysis and pathophysiologic studies are needed.

Analysis of the timing and the usage of drains following cranioplasty on outcomes and the incidence of bone resorption

Background

Pediatric cranioplasty is associated with a high rate of complications, including bone resorption (BR) in 20-50% of cases. We aimed to evaluate factors contributing to BR, including the effect of the timing of cranioplasty and the use of post-surgical drains.

Methods

This is a dual institution retrospective review of all patients under 18 years old who underwent a cranioplasty following a decompressive craniectomy (DC) for the treatment of traumatic brain injury between 2011 and 2021. Early cranioplasty was defined as within 30 days after DC and late cranioplasty as >30 days. Patients were grouped by BR and separately by timing to cranioplasty. Groups were compared based on the Glasgow Outcome Scale (GOS) and postoperative drain usage.

Results

A total of 30 patients were included in the study. The mean age was 7.39 (standard deviation = 6.52) and 60% were male. The median time to cranioplasty was 13 days (interquartile range = 10-17). BR was present in 16.7% of cases. A subgaleal drain was utilized in 93.3% and an external ventricular drain (EVD) in 63.3% of patients following cranioplasty. Drain usage was not associated with BR and timing to cranioplasty was not associated with discharge or 6-month GOS.

Conclusion

This study demonstrates that early cranioplasty following DC may have similar outcomes to late cranioplasty. Post-surgical EVDs and subgaleal drains did not increase the incidence of BR, suggesting their importance in the postoperative management of these patients.

Decompressive Craniectomy in Pediatric Traumatic Brain Injury: A Retrospective Cohort Study

Decompressive craniectomy (DC) in children with traumatic brain injury (TBI) and refractory raised intracranial pressure (ICP) remains controversial. We aimed to describe the clinical and operative characteristics of children with moderate to severe TBI who underwent DC, and compare outcomes with those who had medical therapy. We performed a retrospective observational cohort study on children < 16 years of age with moderate to severe TBI (Glasgow coma scale [GCS] ≤13) who underwent DC in two pediatric centers in Singapore and China between 2014 and 2017, and compared their outcomes with children who underwent medical treatment, among participating centers of the Pediatric Acute and Critical Care Medicine Asian Network. We defined poor functional outcomes as moderate, severe disability, vegetative or comatose state, or mortality, using the Pediatric Cerebral Performance Category scale. We performed multivariable logistic regression to identify predictors for poor functional outcomes. We analyzed 18 children who underwent DC with 214 who had medical therapy. A greater proportion of children with DC (14, 77.8%) experienced poor functional outcomes, compared with those with medical therapy (87, 41.2%, p = 0.003). Children who underwent DC had fewer median 14-day intensive care unit (ICU)-free days (2.5 days, interquartile range [IQR]: 0.0–5.8 vs. 8.0 days, IQR: 0.0–11.0, p = 0.033), median 28-day hospital-free days (0 day, IQR: 0.0–3.5 vs. 11.0 days, IQR: 0.0–21.0, p = 0.002) and 14-day mechanical ventilation-free days (6.5 days, IQR: 0.0–12.3 vs. 11.0 days, IQR: 3.0–14.0, p = 0.011). After accounting for age, sex, GCS, cerebral edema, uncal herniation, nonaccidental injury, and need for intubation, there was no significant association between DC and poor functional outcomes (adjusted odds ratio: 1.59, 95% confidence interval: 0.35–7.24, p = 0.548). Children with DC had severe injuries, and prolonged hospital and ICU stays. Future studies are needed to understand the effectiveness of DC on children with TBI.

Subdural Hematomas in Adults and Children

Subdural hematoma is a common entity encountered by the neurosurgeon. The disease has acute, subacute, and chronic forms. Management of the disease changes according to the etiology of the lesion, yet the main goals are, as with most neurosurgical interventions, decompression of neural tissue and restoration of perfusion. Due to various forms and causes of the disease such as trauma, anticoagulant/antiaggregant use, arterial rupture, oncologic hemorrhages, intracranial hypotension, and idiopathic hemorrhages, several approaches for management have been documented in the literature. Herewith, we present various up-to-date management options for the disease.

Decompressive Craniectomy for Pediatric Traumatic Brain Injury in Low-and-Middle Income and High Income Countries

Traumatic brain injury is one of the leading causes of mortality and morbidity in children worldwide. In severe cases, high intracranial pressure is the most frequent cause of death. When first-line medical management fails, the neurosurgical procedure of decompressive craniectomy (DC) has been proposed for controlling intracranial pressure and improving the long-term outcomes for children with severe traumatic brain injury. However, the use of this procedure is controversial. The evidence from clinical trials shows some promise for the use of DC as an effective second-line treatment. However, it is limited by conflicting trial results, a lack of trials, and a high risk of bias. Furthermore, most research comes from retrospective observational studies and case series. This narrative review considers the strength of evidence for the use of DC in both a high income country and low-and-middle income country setting and examine how we can improve study design to better assess the efficacy of this procedure and increase the clinical translatability of results to centers worldwide. Specifically, we argue for a need for further studies with higher pediatric participant numbers, multicenter collaboration, and the use of a more consistent methodology to enable comparability of results among settings.

Protocol for the multicentre prospective paediatric craniectomy and cranioplasty registry (pedCCR) under the auspices of the European Society for Paediatric Neurosurgery (ESPN)

PURPOSE

In the paediatric age group, the overall degree of evidence regarding decompressive craniectomy (DC) and cranioplasty is low, whereas in adults, randomised controlled trials and prospective multicentre registries are available. To improve the evidence-based treatment of children, a consensus was reached to establish a prospective registry under the auspices of the European Society for Pediatric Neurosurgery (ESPN).

METHODS

This international multicentre prospective registry is aimed at collecting information on the indication, timing, technique and outcome of DC and cranioplasty in children. The registry will enrol patients ≤ 16 years of age at the time of surgery, irrespective of the underlying medical condition. The study design comprises four obligatory entry points as a core dataset, with an unlimited number of further follow-up entry points to allow documentation until adolescence or adulthood. Study centres should commit to complete data entry and long-term follow-up.

RESULTS

Data collection will be performed via a web-based portal (homepage: www.pedccr.com ) in a central anonymised database after local ethics board approval. An ESPN steering committee will monitor the project's progress, coordinate analyses of data and presentation of results at conferences and in publications on behalf of the study group.

CONCLUSION

The registry aims to define predictors for optimal medical care and patient-centred treatment outcomes. The ultimate goal of the registry is to generate results that are so relevant to be directly transferred into clinical practice to enhance treatment protocols.

Favourable long-term recovery after decompressive craniectomy: the Northern Finland experience with a predominantly adolescent patient cohort

PURPOSE

Decompressive craniectomy (DC) is an effective treatment of intracranial hypertension. Correspondingly, the procedure is increasingly utilised worldwide. The number of patients rendered vegetative following surgery has been a concern-a matter especially important in children, due to long anticipated lifetime. Here, we report the long-term outcomes of all paediatric DC patients from an 11-year period in a tertiary-level centre that geographically serves half of Finland.

METHODS

We identified all patients younger than 18 years who underwent DC in the Oulu University Hospital between the years 2009 and 2019. Outcomes and clinicoradiological variables were extracted from the patient records.

RESULTS

Mean yearly prevalence of brain injury requiring DC was 1.34/100 000 children-twenty-four patients underwent DC during the study period and 21 (88%) survived. The median age of the patients was 16.0 years, and the median preoperative GCS was 5.0 (IQR 5.0). Fifteen patients (63%) had made a good recovery (Extended Glasgow Outcome Scale ≥ 7). Of the surviving patients, two (9.5%) had not returned to school. After traumatic brain injury (n = 20), the Rotterdam CT score (mean 3.0, range 1 to 5) was not associated with mortality, poor recovery or inability to continue school (p = 0.13, p = 0.41, p = 0.43, respectively). Absent basal cisterns were associated with mortality (p = 0.005), but not with poor recovery if the patient survived DC (p = 0.81). Hydrocephalus was associated with poor recovery and inability to continue school (p = 0.01 and p = 0.03, respectively).

CONCLUSION

Most of our patients made a favourable recovery and were able to continue school. No late mortality was observed. Thus, even in clinically and radiologically severely brain-injured children, decompressive craniectomy appears to yield favourable outcomes.

Hemicraniectomy and externalized ventricular drain placement in a pediatric patient with myelin oligodendrocyte glycoprotein-associated tumefactive demyelinating disease

BACKGROUND

Acquired demyelination of the central nervous system in children can manifest as multiple sclerosis, neuromyelitis optica, myelin oligodendrocyte glycoprotein (MOG)-associated demyelination, or as an acute monophasic illness without serum antibodies. Rarely do patients with demyelinating disease need surgical intervention for fulminant crises.

CASE

We report a case of anti-MOG antibody-related tumefactive demyelination in a 10-year-old female who required urgent hemicraniectomy and external ventricular drain placement for progressive white matter edema with obstructive hydrocephalus, subfalcine, and transtentorial herniation.

Two-center validation of the Oulu resorption score for bone flap resorption after autologous cranioplasty

OBJECTIVE

Autologous bone has been the gold standard of cranioplasty materials for decades. Unique to autologous cranioplasty, bone flap resorption is a poorly understood and unclearly defined complication. Even further, it has been unclear, whether the resorption process eventually stabilizes over time. Thus, the sufficient follow-up period after autologous cranioplasty is unknown. The Oulu Resorption Score (ORS) is a straight-forward classification system for the radiological interpretation of bone flap resorption. The aims of the present study were to evaluate the reliability of the ORS using intra-class correlation coefficient (ICC) and to assess the temporal progression of the resorption process.

METHODS

We identified 108 consecutive autologous cranioplasty patients treated between 2005 and 2018 in two tertiary referral centers. All 365 head CT scans the patients had undergone were evaluated using the ORS in a blinded, independent two-center setting. Intra- and inter-observer reliabilities were calculated. The ORS was applied to study the temporal progression of the resorption process.

RESULTS

The intra-observer reliability of the ORS was excellent (ICC 0.94, 95%CI 0.93-0.95). Inter-observer reliability was good-to-excellent (ICCs 0.87 and 0.89, 95%CIs 0.84-0.89 and 0.87-0.91, respectively). In scatterplot smoothing analyses, the progression of bone flap resorption appeared to stabilize 12-24 months after cranioplasty.

CONCLUSIONS

ORS is the only validated radiological tool for the standardized analysis of bone flap resorption after autologous cranioplasty. Evaluated using the ORS, the resorption process seemed to stabilize during the first two postoperative years after cranioplasty, suggesting that the sufficient follow-up time after autologous cranioplasty is two years.

Bone Flap Resorption in Pediatric Patients Following Autologous Cranioplasty

Following a decompressive craniectomy, the autologous bone flap is generally considered the reconstructive material of choice in pediatric patients. Replacement of the original bone flap takes advantage of its natural biocompatibility and the associated low risk of rejection, as well as the potential to reintegrate with the adjacent bone and subsequently grow with the patient. However, despite these advantages and unlike adult patients, the replaced calvarial bone is more likely to undergo delayed bone resorption in pediatric patients, ultimately requiring revision surgery. In this review, we describe the materials that are currently available for pediatric cranioplasty, the advantages and disadvantages of autologous calvarial replacement, the incidence and classification of bone resorption, and the clinical risk factors for bone flap resorption that have been identified to date.

Consensus statement from the international consensus meeting on post-traumatic cranioplasty

Background

Due to the lack of high-quality evidence which has hindered the development of evidence-based guidelines, there is a need to provide general guidance on cranioplasty (CP) following traumatic brain injury (TBI), as well as identify areas of ongoing uncertainty via a consensus-based approach.

Methods

The international consensus meeting on post-traumatic CP was held during the International Conference on Recent Advances in Neurotraumatology (ICRAN), in Naples, Italy, in June 2018. This meeting was endorsed by the Neurotrauma Committee of the World Federation of Neurosurgical Societies (WFNS), the NIHR Global Health Research Group on Neurotrauma, and several other neurotrauma organizations. Discussions and voting were organized around 5 pre-specified themes: (1) indications and technique, (2) materials, (3) timing, (4) hydrocephalus, and (5) paediatric CP.

Results

The participants discussed published evidence on each topic and proposed consensus statements, which were subject to ratification using anonymous real-time voting. Statements required an agreement threshold of more than 70% for inclusion in the final recommendations.

Conclusions

This document is the first set of practical consensus-based clinical recommendations on post-traumatic CP, focusing on timing, materials, complications, and surgical procedures. Future research directions are also presented.

Barrel Stave Osteotomy Decompression for Acute Brain Injury in Infants: Technical Note

Decompressive craniectomy (DC) is rarely required in infants, but when performed several aspects should be considered: These youngest patients are vulnerable to blood loss and cranial reconstruction can be challenging due to skull growth and bone flap resorption. On the other hand, infants have thin and flexible bone and osteogenic potential. The authors propose a technique which makes use of these unique aspects by achieving decompression with the craniofacial method of barrel stave osteotomy, aiming to achieve adequate DC, limit perioperative risks and facilitate subsequent cranial reconstruction.

Decompressive craniectomy for the treatment of high intracranial pressure in closed traumatic brain injury

BACKGROUND

High intracranial pressure (ICP) is the most frequent cause of death and disability after severe traumatic brain injury (TBI). It is usually treated with general maneuvers (normothermia, sedation, etc.) and a set of first-line therapeutic measures (moderate hypocapnia, mannitol, etc.). When these measures fail, second-line therapies are initiated, which include: barbiturates, hyperventilation, moderate hypothermia, or removal of a variable amount of skull bone (secondary decompressive craniectomy).

OBJECTIVES

To assess the effects of secondary decompressive craniectomy (DC) on outcomes of patients with severe TBI in whom conventional medical therapeutic measures have failed to control raised ICP.

SEARCH METHODS

The most recent search was run on 8 December 2019. We searched the Cochrane Injuries Group's Specialised Register, CENTRAL (Cochrane Library), Ovid MEDLINE(R), Ovid MEDLINE(R) In-Process & Other Non-Indexed Citations, Ovid MEDLINE(R) Daily and Ovid OLDMEDLINE(R), Embase Classic + Embase (OvidSP) and ISI Web of Science (SCI-EXPANDED & CPCI-S). We also searched trials registries and contacted experts.

SELECTION CRITERIA

We included randomized studies assessing patients over the age of 12 months with severe TBI who either underwent DC to control ICP refractory to conventional medical treatments or received standard care.

DATA COLLECTION AND ANALYSIS

We selected potentially relevant studies from the search results, and obtained study reports. Two review authors independently extracted data from included studies and assessed risk of bias. We used a random-effects model for meta-analysis. We rated the quality of the evidence according to the GRADE approach.

MAIN RESULTS

We included three trials (590 participants). One single-site trial included 27 children; another multicenter trial (three countries) recruited 155 adults, the third trial was conducted in 24 countries, and recruited 408 adolescents and adults. Each study compared DC combined with standard care (this could include induced barbiturate coma or cooling of the brain, or both). All trials measured outcomes up to six months after injury; one also measured outcomes at 12 and 24 months (the latter data remain unpublished). All trials were at a high risk of bias for the criterion of performance bias, as neither participants nor personnel could be blinded to these interventions. The pediatric trial was at a high risk of selection bias and stopped early; another trial was at risk of bias because of atypical inclusion criteria and a change to the primary outcome after it had started. Mortality: pooled results for three studies provided moderate quality evidence that risk of death at six months was slightly reduced with DC (RR 0.66, 95% CI 0.43 to 1.01; 3 studies, 571 participants; I² = 38%; moderate-quality evidence), and one study also showed a clear reduction in risk of death at 12 months (RR 0.59, 95% CI 0.45 to 0.76; 1 study, 373 participants; high-quality evidence). Neurological outcome: conscious of controversy around the traditional dichotomization of the Glasgow Outcome Scale (GOS) scale, we chose to present results in three ways, in order to contextualize factors relevant to clinical/patient decision-making. First, we present results of death in combination with vegetative status, versus other outcomes. Two studies reported results at six months for 544 participants. One employed a lower ICP threshold than the other studies, and showed an increase in the risk of death/vegetative state for the DC group. The other study used a more conventional ICP threshold, and results favoured the DC group (15.7% absolute risk reduction (ARR) (95% CI 6% to 25%). The number needed to treat for one beneficial outcome (NNTB) (i.e. to avoid death or vegetative status) was seven. The pooled result for DC compared with standard care showed no clear benefit for either group (RR 0.99, 95% CI 0.46 to 2.13; 2 studies, 544 participants; I² = 86%; low-quality evidence). One study reported data for this outcome at 12 months, when the risk for death or vegetative state was clearly reduced by DC compared with medical treatment (RR 0.68, 95% CI 0.54 to 0.86; 1 study, 373 participants; high-quality evidence). Second, we assessed the risk of an 'unfavorable outcome' evaluated on a non-traditional dichotomized GOS-Extended scale (GOS-E), that is, grouping the category 'upper severe disability' into the 'good outcome' grouping. Data were available for two studies (n = 571). Pooling indicated little difference between DC and standard care regarding the risk of an unfavorable outcome at six months following injury (RR 1.06, 95% CI 0.69 to 1.63; 544 participants); heterogeneity was high, with an I² value of 82%. One trial reported data at 12 months and indicated a clear benefit of DC (RR 0.81, 95% CI 0.69 to 0.95; 373 participants). Third, we assessed the risk of an 'unfavorable outcome' using the (traditional) dichotomized GOS/GOS-E cutoff into 'favorable' versus 'unfavorable' results. There was little difference between DC and standard care at six months (RR 1.00, 95% CI 0.71 to 1.40; 3 studies, 571 participants; low-quality evidence), and heterogeneity was high (I² = 78%). At 12 months one trial suggested a similar finding (RR 0.95, 95% CI 0.83 to 1.09; 1 study, 373 participants; high-quality evidence). With regard to ICP reduction, pooled results for two studies provided moderate quality evidence that DC was superior to standard care for reducing ICP within 48 hours (MD -4.66 mmHg, 95% CI -6.86 to -2.45; 2 studies, 182 participants; I² = 0%). Data from the third study were consistent with these, but could not be pooled. Data on adverse events are difficult to interpret, as mortality and complications are high, and it can be difficult to distinguish between treatment-related adverse events and the natural evolution of the condition. In general, there was low-quality evidence that surgical patients experienced a higher risk of adverse events.

AUTHORS' CONCLUSIONS

Decompressive craniectomy holds promise of reduced mortality, but the effects of long-term neurological outcome remain controversial, and involve an examination of the priorities of participants and their families. Future research should focus on identifying clinical and neuroimaging characteristics to identify those patients who would survive with an acceptable quality of life; the best timing for DC; the most appropriate surgical techniques; and whether some synergistic treatments used with DC might improve patient outcomes.