Complications of decompressive craniectomy for head injury

Three-Pillar Expansive Craniotomy in Children with Acute Ruptured Supratentorial Brain Arteriovenous Malformations

OBJECTIVE

Acute rupture and hemorrhage of pediatric brain arteriovenous malformations (AVMs) may lead to cerebral herniation or intractable intracranial hypertension, necessitating emerging surgical interventions to alleviate intracranial pressure. However, there is still controversy regarding the timing of treatment for ruptured AVMs. This study aimed to assess the feasibility of utilizing three-pillar expansive craniotomy (3PEC) at different times during the treatment of pediatric ruptured supratentorial AVMs.

METHODS

A retrospective analysis was conducted on all consecutive cases of acute rupture in supratentorial AVM children who underwent 3PEC at a single institution from 2020 to 2022. General information, clinical characteristics, radiological data, and prognosis were reviewed and analyzed.

RESULTS

Thirteen children were included in the analysis. The intracranial pressure of all patients decreased to below 15 mmHg within 10 days. The expansion volume of the cranial cavity of the patients increased by 18.3 cm3 (95% confidence interval, 10.2-26.3; P < 0.001) compared to the hematoma volume. None of the patients required decompressive craniectomy due to intractable intracranial hypertension caused by cerebral swelling. The median waiting period for patients with delayed AVMs treatment was 8 days, during which no rebleeding occurred.

CONCLUSIONS

Emergency intervention with 3PEC in children experiencing acutely ruptured supratentorial AVMs appears to be feasible. For children requiring delayed management of the AVMs, 3PEC may diminish the risk of rebleeding during the waiting period and shorten the waiting period.

Subcutaneous preservation versus cryopreservation of autologous bone grafts for cranioplasty: A systematic review and meta-analysis

BACKGROUND

Cranioplasty corrects cranial bone defects using various bone substitutes or autologous bone flaps created during a previous craniectomy surgery. These autologous bone flaps can be preserved through subcutaneous preservation (SP) or cryopreservation (CP).

AIM

We aim to compare outcomes and complications for both SP and CP techniques to enhance the current evidence about autologous bone flap preservation.

METHODS

Five electronic databases were searched to collect all relevant studies. Records were screened for eligibility. Data were extracted from the included studies independently. We categorized surgical site infection (SSI) as either due to Traumatic brain injury (TBI) or not to reveal potential variations in SSI incidence. The double-arm meta-analysis utilized risk ratios (RR) and mean differences (MD) with corresponding confidence intervals (CI) to pool categorical and continuous outcomes, respectively. Proportions with their respective 95% CIs were pooled for single-arm meta-analyses to determine outcomes related to SP technique.

RESULTS

Seventeen studies involving 1169 patients were analyzed. No significant difference in SSI rates was observed between SP and CP methods in patients with or without TBI. SP was linked to shorter hospital stays in two studies (194 patients). Single-arm analysis showed a 17% revision surgery rate across five studies (375 patients) and infection rates in 17 studies for SP. New bone formation occurred in 13.2% of patients, with 19.9% showing resorption.

CONCLUSION

SP and CP methods showed similar SSI rates post-craniectomy in TBI and non-TBI patients. SP was associated with reduced hospitalization time, low infection rates, and a moderate need for revision surgery.

A comprehensive systematic review and meta-analysis study in comparing decompressive craniectomy versus craniotomy in patients with acute subdural hematoma

There are two controversial surgery methods which are traditionally used: craniotomy and decompressive craniectomy. The aim of this study was to evaluate the efficacy and complications of DC versus craniotomy for surgical management in patients with acute subdural hemorrhage (SDH) following traumatic brain injury (TBI). We conducted a comprehensive search on PubMed, Scopus, Web of Science, and Embase up to July 30, 2023, using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist. Relevant articles were reviewed, with a focus on studies comparing decompressive craniectomy to craniotomy techniques in patients with SDH following TBI. Ten studies in 2401 patients were reviewed. A total of 1170 patients had a craniotomy, and 1231 had decompressive craniectomy. The mortality rate was not significantly different between the two groups (OR: 0.46 [95% CI: 0.42-0.5] P-value: 0.07). The rate of revision surgery was insignificantly different between the two groups (OR: 0.59 [95% CI: 0.49-0.69] P-value: 0.08). No significant difference was found between craniotomy and decompressive craniectomy regarding unilateral mydriasis (OR: 0.46 [95% CI: 0.35-0.57] P-value < 0.001). However, the craniotomy group had significantly lower rates of non-pupil reactivity (OR: 0.27 [95% CI: 0.17-0.41] P-value < 0.001) and bilateral mydriasis (OR: 0.59 [95% CI: 0.5-0.66] P-value: 0.04). There was also no significant difference in extracranial injury between the two groups, although the odds ratio of significant extracranial injury was lower in the craniotomy group (OR: 0.58 [95% CI: 0.45-0.7] P-value: 0.22). Our findings showed that non-pupil and bilateral-pupil reactivity were significantly more present in decompressive craniectomy. However, there was no significant difference between the two groups regarding mortality rate, extracranial injury, revision surgery, and one-pupil reactivity.

Reconstruction of the temporal line for sinking skin flap syndrome using split rib grafts: a technical note

Sinking skin flap syndrome (SSFS), also known as syndrome of the trephined, is one of the complications of decompressive craniectomy. The definitive treatment for the condition is cranioplasty, but there are cases where that is not an option. We report a seventy-seven-year-old male patient with disturbance of consciousness after removal of infected bone flap and debridement. The skin showed marked depression and SSFS was diagnosed. The scalp had contracted due to infection and debridement so as to need skin grafting. Cranioplasty with a full-size bone flap was not an option. Reconstruction of the temporal line with autologous rib graft was performed. The patient became alert after the operation.

Prolonged course of brain edema and neurological recovery in a translational model of decompressive craniectomy after closed head injury in mice

Background

The use of decompressive craniectomy in traumatic brain injury (TBI) remains a matter of debate. According to the DECRA trial, craniectomy may have a negative impact on functional outcome, while the RescueICP trial revealed a positive effect of surgical decompression, which is evolving over time. This ambivalence of craniectomy has not been studied extensively in controlled laboratory experiments.

Objective

The goal of the current study was to investigate the prolonged effects of decompressive craniectomy (both positive and negative) in an animal model.

Methods

Male mice were assigned to the following groups: sham, decompressive craniectomy, TBI and TBI followed by craniectomy. The analysis of functional outcome was performed at time points 3d, 7d, 14d and 28d post trauma according to the Neurological Severity Score and Beam Balance Score. At the same time points, magnetic resonance imaging was performed, and brain edema was analyzed.

Results

Animals subjected to both trauma and craniectomy presented the exacerbation of the neurological impairment that was apparent mostly in the early course (up to 7d) after injury. Decompressive craniectomy also caused a significant increase in brain edema volume (initially cytotoxic with a secondary shift to vasogenic edema and gliosis). Notably, delayed edema plus gliosis appeared also after decompression even without preceding trauma.

Conclusion

In prolonged outcomes, craniectomy applied after closed head injury in mice aggravates posttraumatic brain edema, leading to additional functional impairment. This effect is, however, transient. Treatment options that reduce brain swelling after decompression may accelerate neurological recovery and should be explored in future experiments.

Malignant bihemispheric cerebral edema after cranioplasty - An extension of the Monro-Kellie doctrine and predictive factors

Background

Several changes in normal pressure dynamics on the brain occur with a decompressive craniectomy and subsequent cranioplasty. Dead space volume is an important factor contributing to intracranial volume postcranioplasty. A decrease in this volume due to negative suction drain along with relative negative pressure on the brain with the loss of external atmospheric pressure may lead to fatal cerebral edema.

Case Description

A 52-year-old gentleman with a 210 mL volume and middle cerebral artery territory infarction underwent an emergency craniectomy and 6 months later a titanium mold cranioplasty. Precranioplasty computed tomography (CT) scan evaluation revealed a sunken skin flap with a 9 mm contralateral midline shift. Immediately following an uneventful surgery, the patient had sudden fall in blood pressure to 60/40 mmHg and over a few min had dilated fixed pupils. CT revealed severe diffuse cerebral edema in bilateral hemispheres with microhemorrhages and expansion of the sunken right gliotic brain along with ipsilateral ventricular dilatation. Despite undergoing a contralateral decompressive craniectomy due to the midline shift toward the right, the outcome was fatal.

Conclusion

Careful preoperative risk assessment in cranioplasty and close monitoring postprocedure is crucial, especially in malnourished, poststroke cases, with a sinking skin flap syndrome, and a long interval between decompressive craniectomy and cranioplasty. Elective preventive measures and a low threshold for CT scanning and removal of the bone flap or titanium mold are recommended.

Space-expanding flap in decompressive hemicraniectomy for stroke

OBJECTIVE

Decompressive hemicraniectomy (DCE) is the standard of care for space-occupying malignant infarction of the medial cerebral artery in suitable patients. After DCE, the brain is susceptible to trauma and at risk for the syndrome of the trephined. This study aimed to assess the feasibility of using temporary space-expanding flaps, implanted during DCE, to shield the brain from these risks while permitting the injured brain to expand.

METHODS

The authors performed a prospective feasibility study to analyze the safety of space-expanding flaps in 10 patients undergoing DCE and evaluated clinical and radiological outcomes.

RESULTS

The relatives of 1 patient withdrew consent, leaving 9 patients in the final analysis. No patients required removal of the space-expanding flap because of uncontrolled increase of intracranial pressure or infection. One patient required additional external ventricular drainage and 1 received mannitol. The mean (range) midline shift decreased from 6.67 (3-12) mm to 1.26 (0-2.6) mm after DCE with the space-expanding flap. The authors observed no cases of sinking skin flap syndrome, other complications, or deaths. One patient underwent further treatment due to infection of the reimplanted autologous bone flap. Two patients later refused cranioplasty, preferring to keep the space-expanding flap and thus avoid the potential risks of cranioplasty.

CONCLUSIONS

This feasibility study showed that the concurrent use of space-expanding flaps appeared to be safe in patients who underwent DCE for malignant infarction of the medial cerebral artery. Moreover, space-expanding flaps may permit patients to avoid a second surgery for reimplantation of the autologous bone flap and the risks inherent to this procedure.

Decompressive Craniectomy for the Treatment of Severe Diffuse Traumatic Brain Injury: A Randomized Controlled Trial

Background  Severe traumatic brain injury (TBI) is one of the leading public health problems across the world. TBI is associated with high economic costs to the healthcare system specially in developing countries. Decompressive craniectomy is a procedure in which an area of the skull is removed to increase the volume of intracranial compartment. There are various techniques of decompressive craniectomy used that include subtemporal and circular decompression, and unilateral or bilateral frontotemporoparietal decompression. Objective  The aim of this study was to compare the outcome of decompressive craniectomy for the management of severe TBI versus conservative management alone at the Department of Neurosurgery, Abbasi Shaheed Hospital, Karachi, Pakistan. Methods  The study (randomized controlled trial) was conducted from February 1, 2014, till June 30, 2017. Results  A total of 136 patients were included after following the inclusion criteria. They were randomly assigned to two groups, making it 68 patients in each study group. There were 89 males and 47 females. All the patients received standard care recommended by the Brain Trauma Foundation. The mortality rate observed at 6 months in decompressive craniectomy was 22.05%, while among conservative management group, it was 45.58%. Difference in mortality of both groups at 6 months was significant. Total 61.76% (42) of patients from decompressive craniectomy group had a favorable outcome (Glasgow outcome scale: 4-5) at 6 months. While among conservative management group, total 35.29% (24) had a favorable outcome (Glasgow outcome scale: 4-5). Difference in Glasgow outcome scale at 6 months of both groups was significant. Conclusion  In conclusion, decompressive craniectomy is simple, safe, and better than conservative management alone.

Systematic Review of Syndrome of the Trephined and Reconstructive Implications

Syndrome of the trephined (SoT) is a severe complication following decompressive craniectomy resulting in neurological decline which can progress to aphasia, catatonia, and even death. While cranioplasty can reverse neurological symptoms of SoT, awareness of SoT is poor outside of the neurosurgery community. The authors performed a systematic review of the literature on SoT with a focus on reconstructive implications. Search terms "syndrome of the trephined" and "sunken flap syndrome" were applied to PubMed to identify primary studies through October 2021. Full-text review yielded 11 articles discussing SoT and reconstructive techniques or implications with 56 patients undergoing cranial reconstruction. Average age of the patients was 41.8±9.5 years. Sixty-three percent of the patients were male. The most common indication for craniectomy was traumatic brain injury (43%), followed by tumor resection (23%), intracerebral hemorrhage (11%), and aneurysmal subarachnoid hemorrhage (2%). Patients most commonly suffered from motor deficits (52%), decreased wakefulness (30%), depression or anxiety (21%), speech deficits (16%), headache (16%), and cognitive difficulties (2%). Time until presentation of symptoms following decompression was 4.4±8.9 months. Patients typically underwent cranioplasty with polyetheretherketone (48%), titanium mesh (21%), split thickness calvarial bone (16%), full thickness calvarial bone (14%), or split thickness rib graft (4%). Eight percent of patients required free tissue transfer for soft tissue coverage. Traumatic Brain Injury (TBI) was a risk factor for development of SoT when adjusting for age and sex (odds ratio: 8.2, 95% confidence interval: 1.2-8.9). No difference significant difference was observed between length until initial improvement of neurological symptoms following autologous versus allograft reconstruction (P=0.47). SoT can be a neurologically devastating complication of decompressive craniectomy which can resolve following urgent cranioplasty. Familiarity with this syndrome and its reconstructive implications is critical for the plastic surgery provider, who may be called upon to assist with these urgent cases.

Prediction of Shunt-Dependent Hydrocephalus after Primary Supratentorial Intracerebral Hemorrhage with a Focus on the Influence of Craniectomies

Objective

Hydrocephalus after intracerebral hemorrhage (ICH) is known to be related to poor prognosis and mortality. We analyzed predictors of permanent hydrocephalus in the patients with surgically treated supratentorial ICH.

Methods

From 2004 to 2019, a total of 414 patients with surgically treated primary supratentorial ICH were included. We retrospectively analyzed age, sex, preexisting hypertension and diabetes, location and volume of ICH, presence and severity of intraventricular hemorrhage (IVH), and type of surgery.

Results

Forty patients (9.7%) required shunt surgery. Concomitant IVH was higher in the 'shunt required' group (92.5%) than in the 'shunt not required' group (67.9%) (p=0.001). IVH severity was worse in the 'shunt required' group (13.5 vs. 7.5, p=0.008). Craniectomy (47.5%) was significantly high in the 'shunt required' group. According to multivariable analysis, the presence of an IVH was 8.1 times more frequent and craniectomy was 8.6 times more frequent in the 'shunt required' group. In the comparison between craniotomy and craniectomy group, the presence of an IVH was related with a 3.9 times higher (p=0.033) possibility and craniectomies rather than craniotomies with a 7-times higher possibility of shunt surgery (p<0.001). Within the craniectomy group, an increase in the craniectomy area by 1 cm2 was correlated with a 3.2% increase in the possibility of shunt surgery (odds ratio, 1.032; 95% confidence interval, 1.005-1.061; p=0.022).

Conclusion

Presence of IVH, the severity of IVH and decompressive craniectomy were related to the development of shunt dependent hydrocephalus in the patients with ICH. The increasing size of craniectomy was related with increasing rate of shunt requirement.

Syndrome of the trephined: clinical spectrum, risk factors, and impact of cranioplasty on neurologic recovery in a prospective cohort

Syndrome of the trephined (SoT) is an underrecognized complication after decompressive craniectomy. We aimed to investigate SoT incidence, clinical spectrum, risk factors, and the impact of the cranioplasty on neurologic recovery. Patients undergoing a large craniectomy (> 80 cm²) and cranioplasty were prospectively evaluated using modified Rankin score (mRS), cognitive (attention/processing speed, executive function, language, visuospatial), motor (Motricity Index, Jamar dynamometer, postural score, gait assessment), and radiologic evaluation within four days before and after a cranioplasty. The primary outcome was SoT, diagnosed when a neurologic improvement was observed after the cranioplasty. The secondary outcome was a good neurologic outcome (mRS 0–3) 4 days and 90 days after the cranioplasty. Logistic regression models were used to evaluate the risk factors for SoT and the impact of cranioplasty timing on neurologic recovery. We enrolled 40 patients with a large craniectomy; 26 (65%) developed SoT and improved after the cranioplasty. Brain trauma, hemorrhagic lesions, and shifting of brain structures were associated with SoT. After cranioplasty, a shift towards a good outcome was observed within 4 days (p = 0.025) and persisted at 90 days (p = 0.005). Increasing delay to cranioplasty was associated with decreased odds of improvement when adjusting for age and baseline disability (odds ratio 0.96; 95% CI, 0.93–0.99, p = 0.012). In conclusion, SoT is frequent after craniectomy and interferes with neurologic recovery. High suspicion of SoT should be exercised in patients who fail to progress or have a previous trauma, hemorrhage, or shifting of brain structures. Performing the cranioplasty earlier was associated with improved and quantifiable neurologic recovery.

[The latest study on biomimetic mineralized collagen-based bone materials for pediatric skull regeneration and repair]

As a worldwide challenge in the field of neurosurgery, there is no effective treatment method for pediatric skull defects repair in clinic. Currently clinical used cranioplasty materials couldn't undergo adjustment in response to skull growth and deformation. An ideal material for pediatric cranioplasty should fulfill the requirements of achieving complete closure, good osseointegration, biodegradability and conformability, sufficient cerebral protection and optimal aesthetic, and functional restoration of calvaria. Biomimetic mineralized collagen-based bone material is a kind of material that simulates the microstructural unit of natural bone on the nanometer scale. Because of its high osteogenic activity, it is widely used in repair of all kinds of bone defects. Recently, the biomimetic mineralized collagen-based bone materials have successfully been applied for cranial regeneration and repair with satisfactory results. This review mainly introduces the characteristics of the biomimetic mineralized collagen-based bone materials, the advantages for the repair of pediatric skull defects, and the related progresses.

Scenario for the use of effusion-peritoneal shunt necessary against subdural effusion secondary to decompressive craniectomy

OBJECTIVES

This study aimed to summarize the surgical strategies for subdural effusion secondary to decompressive craniectomy (SESDC) and discuss the applicable scenarios of effusion-peritoneal shunt (EP shunt).

METHODS

A total of 53 consecutive patients with SESDC were screened out of 7569 cases. The SESDC was divided into five types, and the treatment methods of each type were analyzed and compared. According to the implementation strategy of cranioplasty (CP), patients were divided into CP-first and delayed-CP groups. The differences in surgical methods were compared between the two groups.

RESULTS

All patients with SESDC in this cohort had undergone cranioplasty. Subcutaneous puncture and aspiration (SPAA) proved ineffective. Only 2/30 patients in the CP-first group used EP shunt, while 6/19 patients in the delayed-CP group used EP shunt; the difference was statistically significant (P = 0.03). A significant difference was found in the use of EP shunt among type 1, type 2, and type 5 SESDC (χ² = 6.778, P = 0.034).

CONCLUSIONS

CP combined with other treatments could cure most SESDC. EP shunt should be used preferentially in some specific scenarios in which CP cannot be performed first, rather than as a backup measure that can only be used when other preceding treatments fail.

Complications of cranioplasty in relationship to traumatic brain injury: a systematic review and meta-analysis

Despite being a common procedure, cranioplasty (CP) is associated with a variety of serious, at times lethal, complications. This study explored the relationship between the initial injury leading to decompressive craniectomy (DC) and the rates and types of complications after subsequent CP. It specifically compared between traumatic brain injury (TBI) patients and patients undergoing CP after DC for other indications.A comprehensive search of PubMed, Scopus, and the Cochrane Library databases using PRISMA guidelines was performed to include case-control studies, cohorts, and clinical trials reporting complication data for CP after DC. Information about the patients' characteristics and the rates of overall and specific complications in TBI and non-TBI patients was extracted, summarized, and analyzed.A total of 59 studies, including the authors' institutional experience, encompassing 9264 patients (4671 TBI vs. 4593 non-TBI) met the inclusion criteria; this total also included 149 cases from our institutional series. The results of the analysis of the published series are shown both with and without our series 23 studies reported overall complications, 40 reported infections, 10 reported new-onset seizures, 13 reported bone flap resorption (BFR), 5 reported post-CP hydrocephalus, 10 reported intracranial hemorrhage (ICH), and 8 reported extra-axial fluid collections (EFC). TBI was associated with increased odds of BFR (odds ratio [OR] 1.76, p < 0.01) and infection (OR 1.38, p = 0.02). No difference was detected in the odds of overall complications, seizures, hydrocephalus, ICH, or EFC.Awareness of increased risks of BFR and infection after CP in TBI patients promotes the implementation of new strategies to prevent these complications especially in this category of patients.

Complications Following Decompressive Craniectomy

BACKGROUND

 Decompressive craniectomy (DC) has become the definitive surgical procedure to manage a medically intractable rise in intracranial pressure. DC is a life-saving procedure resulting in lower mortality but also higher rates of severe disability. Although technically straightforward, DC is accompanied by many complications. It has been reported that complications are associated with worse outcome. We reviewed a series of patients who underwent DC at our department to establish the incidence and types of complications.

METHODS

 We retrospectively evaluated the incidence of complications after DC performed in 135 patients during the time period from January 2013 to December 2018. Postoperative complications were evaluated using clinical status and CT during 6 months of follow-up. In addition, the impact of potential risk factors on the incidence of complications and the impact of complications on outcome were assessed.

RESULTS

 DC was performed in 135 patients, 93 of these for trauma, 22 for subarachnoid hemorrhage, 13 for malignant middle cerebral artery infarction, and 7 for intracerebral hemorrhage. Primary DC was performed in 120 patients and secondary DC in 15 patients. At least 1 complication occurred in each of 100 patients (74%), of which 22 patients (22%) were treated surgically. The following complications were found: edema or hematoma of the temporal muscle (34 times), extracerebral hematoma (33 times), extra-axial fluid collection (31 times), hemorrhagic progression of contusions (19 times), hydrocephalus (12 times), intraoperative malignant brain edema (10 times), temporal muscle atrophy (7 times), significant intraoperative blood loss (6 times), epileptic seizures (5 times), and skin necrosis (4 times). Trauma (p = 0.0006), coagulopathy (p = 0.0099), and primary DC (p = 0.0252) were identified as risk factors for complications. There was no significant impact of complications on outcome.

CONCLUSIONS

 The incidence of complications following DC is high. However, we did not confirm a significant impact of complications on outcome. We emphasize that some phenomena are so frequent that they can be considered a consequence of primary injury or natural sequelae of the DC rather than its direct complication.

Simultaneous cranioplasty and ventriculoperitoneal shunt placement in patients with traumatic brain injury undergoing unilateral decompressive craniectomy

Hydrocephalus is a common complication after decompressive craniectomy (DC) in patients with traumatic brain injury (TBI). However, the strategy of managing TBI patients with a cranial defect and hydrocephalus remains controversial. Placement of a ventriculoperitoneal shunt (VPS) in patients with a cranial defect and hydrocephalus may aggravate sinking skin flap overlying the cranial defect and result in syndrome of sinking skin flap (SSSF) that causes neurological deterioration. A retrospective analysis of 49 TBI patients who developed hydrocephalus after unilateral DC was undertaken to investigate the safety of simultaneous cranioplasty and VPS placement, and the incidence of SSSF after VPS placement. Among these patients, 17 patients underwent simultaneous cranioplasty and VPS placement, and 32 patients underwent staged cranioplasty and VPS placement. The overall complication rate was 9.3% (3/32) in staged group and 29.4% (5/17) in simultaneous group, respectively. There was no statistically significance between two study groups regarding overall complication (p = 0.11) and reoperation rate (p = 0.47). Two patients with severe brain bulging in staged group developed SSSF after placement of a nonprogrammable VPS. Our study showed that simultaneous cranioplasty and VPS placement may be safe in TBI patients with a cranial defect and hydrocephalus. However, due to the contradictory results about the safety of simultaneous cranioplasty and VPS placement in the literatures, neurosurgeons should carefully consider whether patients are suitable for such treatment. In patients planning to undergo VPS placement first, a programmable shunt may be a better choice for the possibility of SSSF after shunt placement.

Early cranioplasty associated with a lower rate of post-traumatic hydrocephalus after decompressive craniectomy for traumatic brain injury

BACKGROUND

Post-traumatic hydrocephalus (PTH) is one of the primary complications during the course of traumatic brain injury (TBI). The aim of this study was to define factors associated with the development of PTH in patients who underwent unilateral decompressive craniectomy (DC) for TBI.

METHODS

A total of 126 patients, who met the inclusion criteria of the study, were divided into two groups: patients with PTH (n = 25) and patients without PTH (n = 101). Their demographic, clinical, radiological, operative, and postoperative factors, which may be associated with the development of PTH, were compared.

RESULTS

Multivariate logistic regression analysis revealed that cranioplasty performed later than 2 months following DC was significantly associated with the requirement for ventriculoperitoneal shunting due to PTH (p < 0.001). Also, a significant unfavorable outcome rate was observed in patients with PTH at 1-year follow-up according to the Glasgow Outcome Scale-Extended (p = 0.047).

CONCLUSIONS

Our results show that early cranioplasty within 2 months after DC was associated with a lower rate of PTH development after TBI.

Cranioplasty length of stay: Relationship with indication, surgical decision-making factors, and sex

Objectives

Cranioplasty is being performed more often due to rising rates of decompressive craniectomy. Hospital length of stay is a quality metric which has not been directly studied after cranioplasty. This study aims to identify factors associated with length of stay after cranioplasty to better understand their outcomes.

Patients and methods

A retrospective review was conducted at a single academic center from 2007 to 2015 for all patients >18 years of age who received cranioplasty. Baseline data from 148 patients were recorded including demographics, clinical characteristics, and surgeon decision-making factors for cranioplasty. Post-operative complications within 30 days after cranioplasty were recorded in addition to disposition and discharge data. Weibull accelerated failure time models were used to identify significant associations with length of stay after cranioplasty.

Results

The overall post-operative complication rate was 27.0%, and the most frequent indication for craniectomy was traumatic brain injury. The majority (72.3%) of patients returned home, compared to other disposition, and median length of stay was 2.0 days (interquartile range = 2.0). Average length of stay was 7.7 days in men, as compared with 2.4 days in women, and even upon adjusting for covariate effects, length of stay was longer in men than in women irrespective of post-operative complications. When time-to-cranioplasty fell between 0 and 30 days, average length of stay was 19.2 days, as compared with 10.3 days when time-to-cranioplasty fell between 30 and 90 days, and 2.5 days when time-to-cranioplasty was >90 days. After adjustment for covariate effects, the association between time-to-cranioplasty and length of stay was maintained only in patients without post-operative complications.

Conclusions

Length of stay can inform our understanding of outcomes after cranioplasty. In our study, length of stay was associated with sex, indication for craniectomy, and surgical decision-making (time-to-cranioplasty and implant material), but time-to-cranioplasty was only associated in patients without post-operative complications. These relationships should be seen not as direct causation, but rather as tools to add to our understanding of this relatively complicated procedure.

Cranioplasty With Autogenous Frozen and Autoclaved Bone: Management and Treatment Outcomes

Cranioplasty is a widely employed procedure for restoration of calvarial form and shape. The use of autogenous bone flap offers biological reconstruction with minimal donor site morbidity. One of the options to re-use bone autograft is low temperature preservation followed by autoclaving during cranioplasty. A retrospective evaluation of 12 patients with a mean age of 32.58 ± 10.04 years who underwent frozen autogenous autoclaved bone cranioplasty was done. Cranial bone flaps were removed during the initial craniectomy and stored at 4°C for 20 minutes followed by preservation at -40°C in the deep freezer of the blood bank. Cranioplasty subsequently was performed at a mean time period of 172.17 ± 26.20 days by thawing the bone at room temperature followed by autoclaving at 121°C under 15 psi for 40 minutes. Data regarding patients' characteristics and complications were recorded. Clinical outcomes based on skull shape and symmetry, cosmesis and scars were analyzed by a panel of 4 raters, including 3 doctors and 1 patient. Radiological outcomes were analyzed based on remaining bone thickness and bone gap widening. The present study revealed functionally, structurally, and cosmetically satisfying results. All the cases had satisfactory healing and no incidence of bone graft infection. The skull shape and symmetry, cosmesis and scars revealed excellent to moderate improvement in three-fourth of the patients. Radiological outcomes revealed none of the patients had severe resorption requiring surgical revision with excellent to good implant alignment in 92% of cases. It was concluded that frozen autogenous cranial bone flaps sterilized by autoclaving is safe and effective material for cranioplasty.

Comparison between the different types of heterologous materials used in cranioplasty: a systematic review of the literature

INTRODUCTION

The choice of heterologous materials for cranioplasty after decompressive craniectomy is still difficult. The aim of this study is to examine the association between material of choice and related complications to suggest the best treatment option.

EVIDENCE ACQUISITION

A systematic review was performed for articles reporting cranioplasty comparing the following heterologous implants: titanium, poli-methyl-methacrylate (PMMA), polyetheretherketone (PEEK) and hydroxyapatite (HA). Extracted data included implant materials and incidence of the most frequent complications.

EVIDENCE SYNTHESIS

The final selection resulted in 106 papers but according to our rules only 27 studies were included in the final analysis. Among a total of 1688 custom-made prosthesis implanted, 649 were titanium (38.49%), 298 PMMA (17.56%), 233 PEEK (13.82%), and 508 were HA (30.13%). A total of 348 complications were recorded out of 1688 reported patients (20.64%). In the titanium group, 139 complications were recorded (21.42%); in the PMMA group 57 (19.26%), in the PEEK group 49 (21.03%) and in the HA group 103 (20.3%). If we examine a summary of the reported complications clearly related to cranioplasty (postoperative infections, fractures and prosthesis displacement) versus type of material in multicentric and prospective studies we can see how HA group patients have less reported infections and cranioplasty explantation after infections than PMMA, PEEK and titanium. On the contrary HA patients seem to have a higher number of prosthesis displacement again if compared with the other materials. Since these data are not derived from a statistically correct analysis they should be used only to help to differentiate the properties of the various heterologous cranioplasties.

CONCLUSIONS

The ideal material for all heterologous cranioplasty has not yet been identified. The choice of material should be based on the clinical data of patients, such as the craniectomy size, presence of seizures, possibility of recovery, good long-term outcome associated with a cost analysis.

Tuning pore features of mineralized collagen/PCL scaffolds for cranial bone regeneration in a rat model

Porosity is indispensable for a bone tissue-engineered scaffold for facilitating endogenous cell migration and nascent bone ingrowth. In large-sized cranial bone defect repair, porous scaffolds meet great challenges to match cranial bone regeneration and provide sufficient protection with structural integrity. Therefore, the pore features of the scaffolds for cranial bone regeneration should differ from those typical porous scaffolds used in tubular bone repair and be finely tuned. In this study, a series of porous mineralized collagen/PCL scaffolds with different pore features were fabricated via freeze-drying and applied in a Sprague Dawley rat cranial bone calvarial defect model. The pore size for four groups increased from 10-45 μm to 40-130 μm. As scaffold porosity increased, the compressive strength decreased from 2.09 ± 0.12 MPa to 0.51 ± 0.04 MPa. The micro-computed tomography three-dimensional reconstruction images showed that as pore size and porosity increased, the amount of new bone formation had a maximum in group 3 (pore size: 20-100 μm, compressive strength: 1.06 ± 0.03 MPa). In addition, the histological and histomorphometric analyses showed a consistent tendency which confirmed the Micro-CT results. Meanwhile, histological findings including bony bridging, tissue response at the bone-implant interface and fibrous capsule thickness indicated that the dura mater pathway played the most important role in the regenerative process of this calvarial defect model.

Using titanium mesh to replace the bone flap during decompressive craniectomy: A medical hypothesis

Decompressive craniectomy (DC) plays a significant role in treating refractory intracranial hypertension. During this surgical procedure, part of the skull is removed and the underlying dura mater is open, which can effectively release intracranial pressure. However, in some cases, the decision whether or not to remove the bone flap relies on the surgeon's personal experience. Positive decisions are usually made to avoid massive postoperative cerebral edema and infarction, which can lead to overtreatment. The procedure is related to many side-effects, which may affect the recovery of neurological function. Patients who have survived have to be anesthetized and undergo secondary cranioplasty 3 or 6 months later. Despite its technical simplicity, complications associated with cranioplasty are hard to ignore. Therefore, there is a need for a new surgical procedure combining decompressive craniectomy and cranioplasty. Acute expansion of the skin flap is limited, and the compensatory capacity of the skull after DC depends on the volume of the bone flap at the early stage. The titanium mesh is thin and strong, does not take up extra space provided by bone flap. Therefore, we put forward the concept of Decompressive Bone Flap Replacement. During this procedure, neurosurgeons resect the massive bone flap, open the dura mater, remove the hematoma in a similar manner to a standard craniotomy and then use titanium mesh shaped appropriately to replace the bone flap. Compared with traditional DC, it can ensure the integrity of the skull without affecting the effect of decompression. This paper presents 2 cases of DC and reviews the literature sustaining our hypothesis.

Brain Edema Formation and Functional Outcome After Surgical Decompression in Murine Closed Head Injury Are Modulated by Acetazolamide Administration

Acetazolamide (ACZ), carbonic anhydrase inhibitor, has been successfully applied in several neurosurgical conditions for diagnostic or therapeutic purposes. Furthermore, neuroprotective and anti-edematous properties of ACZ have been postulated. However, its use in traumatic brain injury (TBI) is limited, since ACZ-caused vasodilatation according to the Monro-Kellie doctrine may lead to increased intracranial blood volume / raise of intracranial pressure. We hypothesized that these negative effects of ACZ will be reduced or prevented, if the drug is administered after already performed decompression. To test this hypothesis, we used a mouse model of closed head injury (CHI) and decompressive craniectomy (DC). Mice were assigned into following experimental groups: sham, DC, CHI, CHI+ACZ, CHI+DC, and CHI+DC+ACZ (n = 8 each group). 1d and 3d post injury, the neurological function was assessed according to Neurological Severity Score (NSS) and Beam Balance Score (BBS). At the same time points, brain edema was quantified by MRI investigations. Functional impairment and edema volume were compared between groups and over time. Among the animals without skull decompression, the group additionally treated with acetazolamide demonstrated the most severe functional impairment. This pattern was reversed among the mice with decompressive craniectomy: CHI+DC treated but not CHI+DC+ACZ treated animals showed a significant neurological deficit. Accordingly, radiological assessment revealed most severe edema formation in the CHI+DC group while in CHI+DC+ACZ animals, volume of brain edema did not differ from DC-only animals. In our CHI model, the response to acetazolamide treatment varies between animals with decompressive craniectomy and those without surgical treatment. Opening the cranial vault potentially creates an opportunity for acetazolamide to exert its beneficial effects while vasodilatation-related risks are attenuated. Therefore, we recommend further exploration of this potentially beneficial drug in translational research projects.

Risk factors for the development of seizures after cranioplasty in patients that sustained traumatic brain injury: A systematic review

Decompressive craniectomy (DC) is used for the treatment of raised intracranial pressure secondary to traumatic brain injury. Cranioplasty is a reconstructive procedure that restores the structural integrity of the skull following (DC). Seizures are a recognised complication of cranioplasty but its incidence and risk factors in TBI patients are unclear. Accurate prognostication can help direct prophylactic and treatment strategies for seizures. In this systematic review, we aim to evaluate current literature on these factors. A PROSPERO-registered systematic review was performed in accordance with PRISMA guidelines. Data was synthesised qualitatively and quantitatively in meta-analysis where appropriate. A total of 8 relevant studies were identified, reporting 919 cranioplasty patients. Random-effects meta-analysis reveals a pooled incidence of post-cranioplasty seizures (PCS) of 5.1% (95% CI 2.6-8.2%). Identified risk factors from a single study included increasing age (OR 6.1, p = 0.006), contusion at cranioplasty location (OR 4.8, p = 0.015), and use of monopolar diathermy at cranioplasty (OR 3.5, p = 0.04). There is an association between an extended DC-cranioplasty interval and PCS risk although it did not reach statistical significance (p = 0.062). Predictive factors for PCS are poorly investigated in the TBI population to date. Heterogeneity of included studies preclude meta-analysis of risk factors. Further studies are required to define the true incidence of PCS in TBI and its predictors, and trials are needed to inform management of these patients.

Management of subdural effusion and hydrocephalus following decompressive craniectomy for posttraumatic cerebral infarction in a patient with traumatic brain injury: a case report

Background

Subdural effusion with hydrocephalus (SDEH) is a rare complication of traumatic brain injury, especially following decompressive craniectomy (DC) for posttraumatic cerebral infarction. The diagnosis and treatment are still difficult and controversial for neurosurgeons.

Case presentation

A 45-year-old man developed traumatic cerebral infarction after traumatic brain injury and underwent DC because of the mass effect of cerebral infarction. Unfortunately, the complications of traumatic subdural effusion (SDE) and hydrocephalus occurred in succession following DC. Burr-hole drainage and subdural peritoneal shunt were performed in sequence because of the mass effect of SDE, which only temporarily improved the symptoms of the patient. Cranioplasty and ventriculoperitoneal shunt were performed ultimately, after which SDE disappeared completely. However, the patient remains severely disabled, with a Glasgow Outcome Scale of 3.

Conclusions

It is important for neurosurgeons to consider the presence of accompanying hydrocephalus when treating patients with SDE. Once the diagnosis of SDEH is established and the SDE has no mass effect, timely ventriculoperitoneal shunt may be needed to avoid multiple surgical procedures, which is a safe and effective surgical method to treat SDEH.

Seizures Following Cranioplasty: Risk Factors and Prevention Exploration

BACKGROUND

The aim of this study was to identify risk factors and explore the possible prevention measures for seizures following cranioplasty.

METHODS

The authors performed a retrospective review of 142 consecutive patients who underwent cranioplasty following craniectomy for trauma or cerebral hemorrhage in Dezhou People's Hospital between January 2010 and January 2017. Patients who were diagnosed with aneurysms, arteriovenous malformations, cerebral infarction, and tumors (14), had seizures prior to cranioplasty (9) and those lost to follow-up (7) were excluded. Patients did not use antiepilepsy drugs from treatment of postcranioplasty seizures. The median follow-up time was 51.11 ± 31.59 months (range: 17-98 months). Analyses were performed on a database tracking age, sex, reason for craniectomy, operative time, time between operations, presence of dural substitute, diabetic status, hypertensive status, tobacco use, alcohol use, location of cranioplasty, classification, time and times of seizures following cranioplasty development.

RESULTS

One hundred twelve patients met study criteria. The overall rate of seizures following cranioplasty was 35.7% (40 out of 112 patients). There were no statistically significant associations between postcranioplasty seizures and sex, age, location of cranioplasty, cranioplasty materials, or dural substitute used in craniectomy. Postcranioplasty seizure frequency differed significantly according to reasons for depressive craniectomy. The incidence of postcranioplasty seizures was significantly higher in the first year than in later years. Incidence decreased progressively in subsequent years.

CONCLUSION

Incidence of seizures following cranioplasty was associated with the reason for depressive craniectomy.

Defining "early" cranioplasty to achieve lower complication rates of bone flap failure: resorption and infection

BACKGROUND

Although cranioplasty (CP) is a frequently performed and simple procedure, complications are common, particularly bone flap resorption and infection. The timing of surgery is as an important contributory factor, but the optimal timing has not been clearly determined.

OBJECTIVE

We retrospectively investigated bone flap resorption and surgical site infection after CP to determine the optimal timing of surgery for reduction of complications.

METHODS

The study enrolled 126 patients who underwent decompressive craniectomy (DC) and subsequent CP. Patients with bone flap resorption or surgical site infection were analyzed as the "complication" group. Receiver operating characteristic curve analysis was performed and the Youden index was used to dichotomize "early CP" and "late CP" groups. Univariate and multivariate survival analyses were performed.

RESULTS

The complication group included 42 patients. The Youden index was used to identify a cutoff value for the DC-CP interval of > 44 days, and this was used to define early (< 45 days) and late (≥ 45 days) CP. Late CP was a significant risk factor in univariate and multivariate Cox regression analyses.

CONCLUSION

This study showed that early CP before 45 days after DC is associated with a lower rate of bone flap resorption and surgical site infection than late CP.

Risk factors for seizures after cranioplasty

PURPOSE

Cranioplasty can improve a patient's psychosocial and cognitive functions after decompressive craniectomy, however seizures are a common complication after cranioplasty. The risk factors for early and late seizures after cranioplasty are unclear. This study is to evaluate the risk factors for early and late seizure after cranioplasty.

METHODS

Two hundred and thirty-eight patients who received cranioplasty following craniectomy between January 2012 and December 2014 were included in this study. The risk factors of the patients with early and late post-cranioplasty seizures were compared to those with no post-cranioplasty seizures.

RESULTS

Seizures (73/238, 30.3%) were the most common complication after cranioplasty. Of these 73 patients, 17 (7.1%) had early post-cranioplasty seizures and 56 (23.5%) had late post-cranioplasty seizures. Early post-cranioplasty seizures were related to a longer interval between craniectomy and cranioplasty (P = 0.006), artificial materials (P < 0.001), and patients with late post-craniectomy seizures (P = 0.001). Late post-cranioplasty seizures were related to the presence of neurological deficits (P = 0.042). After stepwise logistic regression analysis, a longer interval between craniectomy and cranioplasty (P = 0.012; OR: 1.004, 95% CI: 1.001-1.007) and late post-craniectomy seizures (P = 0.033; OR: 4.335, 95% CI: 1.127-16.675) were independently associated with early post-cranioplasty seizures.

CONCLUSION

Delayed cranioplasty procedures and seizures before cranioplasty were significantly associated with early post-cranioplasty seizures. Further studies are warranted to investigate whether early surgery after craniectomy can reduce the risk of early post-cranioplasty seizures.

Cranioplasty Using Autologous Bone versus Porous Polyethylene versus Custom-Made Titanium Mesh : A Retrospective Review of 108 Patients

Objective

The purpose of this study was to compare the cosmetic outcome and complications after cranioplasty (CP) due to three different implant materials, and analyze the mean implant survival and cumulative survival rate based on these results.

Methods

We reviewed 108 patients retrospectively who underwent CP between January 2014 and November 2016. Autologous bone (AB; 45 patients) and synthetic materials with porous polyethylene (PP; 32 patients) and custom-made 3-dimensional printed titanium mesh (CT; 31 patients) were used as implants.

Results

Regardless of implanted materials, more than 89.8% of the CP patients were satisfied with the cosmetic outcome. No statistically significant difference was observed among the three groups. The overall postoperative complication rates of each group were 31.1% in the AB group, 15.6% in the PP group and 3.2% in the CT group. The CT group showed lower complication rates compared with AB and PP groups (χ²-test : AB vs. PP, p=0.34; AB vs. CT, p=0.00; PP vs. CT, p=0.03). The AB and PP groups demonstrated a higher post-CP infection rate (11.1% and 6.3%) than the CT group (3.2%). However, no significant difference in the incidence of post-CP infection was observed among the three groups. The PP and CT groups demonstrated a higher mean implant survival time and cumulative survival rate than the AB group at the last follow-up (p<0.05).

Conclusion

In comparison with AB and PP, cranioplasty with CT shows benefits in terms of lower post-CP complication, less intraoperative bleeding loss, shorter operation time and in-hospital stay. The PP and CT groups showed higher implant survival time and cumulative survival rate compared with the AB group.

Early and late clinical outcomes after decompressive craniectomy for traumatic refractory intracranial hypertension: a systematic review and meta-analysis of current evidence

INTRODUCTION

Decompressive craniectomy (DC) to control refractory intracranial hypertension in patients with traumatic brain injury (TBI), has been listed as possible but controversial therapeutic approach in the latest version of TBI management guidelines. This study aimed to perform a systematic review and meta-analysis on efficacy and safety of DC compared to standard care in TBI patients.

EVIDENCE ACQUISITION

A database search from 2011 to 2017 was conducted to identify studies pertinent to DC compared to standard care after TBI. The primary outcomes were mortality and functional outcome upon hospital discharge and at 6 and 12 months after intervention, whereas secondary outcomes were intracranial pressure (ICP) control, hospitalization data and occurrence of adverse events.

EVIDENCE SYNTHESIS

Three randomized controlled trials and two observational studies enrolling 3451 patients were selected for qualitative analysis, among which four were included in the meta-analysis. DC-treated patients showed a significant reduction of overall mortality (RR, 0.57; 95% CI: 0.5-0.66; P<0.001; I2=17%) with no profound beneficial effect on functional outcome (RR, 0.89; 95% CI: 0.78-1.02; P=0.09; I2=58%) compared to those receiving standard care. A more efficient ICP reduction and a tendency towards shorter duration of hospitalization were recorded in DC versus standard care group. Adverse events are more common in DC-treated patients.

CONCLUSIONS

It seems that, in TBI patients with intracranial hypertension, the use of DC is associated with survival benefit when compared to medical therapy alone, but with no clear improvement of functional outcome. Yet no definite conclusion can be drawn due to limited quantity and considerable heterogeneity of available data.

A high-strength mineralized collagen bone scaffold for large-sized cranial bone defect repair in sheep

Large-sized cranial bone defect repair presents a great challenge in the clinic. The ideal cranioplasty materials to realize the functional and cosmetic recovery of the defect must have sufficient mechanical support, excellent biocompatibility, good osseointegration and biodegradability as well. In this study, a high-strength mineralized collagen (MC) bone scaffold was developed with biomimetic composition, microstructure and mechanical properties for the repair of sheep large-sized cranial bone defects in comparison with two traditional cranioplasty materials, polymethyl methacrylate and titanium mesh. The compact MC scaffold showed no distinct pore structure and therefore possessed good mechanical properties. The strength and elastic modulus of the scaffold were much higher than those of natural cancellous bone and slightly lower than those of natural compact bone. In vitro cytocompatibility evaluation revealed that the human bone marrow mesenchymal stem cells (hBMSC) had good viability, attachment and proliferation on the compact MC scaffold indicating its excellent biocompatibility. An adult sheep cranial bone defect model was constructed to evaluate the performances of these cranioplasty materials in repairing the cranial bone defects. The results were investigated by gross observation, computed tomography scanning as well as histological assessments. The in vivo evaluations indicated that compact MC scaffold showed notable osteoconductivity and osseointegration with surrounding cranial bone tissues by promoting bone regeneration. Our results suggested that the compact MC scaffold has a promising potential for large-sized cranial bone defect repair.

Development of Posttraumatic Hydrocephalus Requiring Ventriculoperitoneal Shunt After Decompressive Craniectomy for Traumatic Brain Injury: a Systematic Review and Meta-analysis of Retrospective Studies

BACKGROUND

Decompressive craniotomy (DC) is a known risk factor for the development of posttraumatic hydrocephalus (PTH) in the patients with traumatic brain injury (TBI). Herein, the present study reported the development of PTH requiring ventriculoperitoneal (VP) shunt after DC for TBI.

METHODS

Four databases (PubMed, Web of Science, Scopus, and Cochrane Library) were searched from 1983 to April 2018. The studies evaluating the prevalence of PTH requiring VP shunt after DC in the patients with TBIwere selected without language restriction. A random-effects meta-analysis using event rate (ER) and 95% confidence intervals(CIs), was runby RevMan5.3 software.

RESULTS

Out of 355 studies obtained from the databases, 25 studies were included and analyzed in the meta-analysis. The studies included 2402 patients undergoing DC for TBI, 354 of whohad PTH. The pooled ER of hydrocephalus in the patients undergoing DC for TBI was 17.7% [95%CI: 13.2 to 23.4%; P<0.001]. In addition, the pooled analysis showed that ER of hydrocephalus was 13% in adults [95%CI: 9 to 18.5%; P<0.001] and 37.6% in children [95%CI: 27.79 to 48.7%; P=0.029; I2=0%].

CONCLUSION

The present study demonstrated that DC after TBI was associated with the development of PTH, especially in children compared to adults.

Reduction of Surgical Site Infections After Cranioplasty With Perioperative Bundle

BACKGROUND

Surgical site infections (SSI) are the most common complication after cranioplasty and it is associated with poor prognosis. The aim of this study was to identify the risk factors that triggered the development of SSI after cranioplasty and establish a new perioperative bundle and monitoring system to reduce SSI.

METHODS

A retrospective review of a database that included all cranioplasty patients from 2001 to 2007 was carried out to determine the prevalence of infection. A surveillance team was set up, which assessed the clinical practice and led to the development of a new perioperative bundle and supervision system. A prospective study between 2008 and 2014 was carried out to observe whether infection rates had changed and whether an active surveillance program can change clinical practice.

RESULTS

Retrospective period included 86 adult patients. The overall rate of infection was 10.5% (9 SSI in 86 patients). Age ≥60 years (OR 1.05; 95% CI: 1.00-1.10; P = 0.04), smoking (OR 9.13; 95% CI: 1.65-50.60; P = 0.01), and duration of operation ≥180 minutes (OR1.19; 95% CI: 1.06-1.34; P < 0.01) as significant predictors of postcranioplasty SSI development. Length of preoperative stay and length of hospitalization was significantly longer among infected patients compared with uninfected patients (P < 0.01, respectively). In prospective period, the general SSI rate was reduced to 1.8% (2 SSI in 113 patients). The difference was statistically significant (P = 0.01).

CONCLUSIONS

A perioperative bundle and monitoring system may help to reduce SSI rates after cranioplasty. This work also indicates how an active surveillance program can successfully change clinical practice.

Aseptic Bone Flap Resorption after Cranioplasty with Autologous Bone: Incidence, Risk Factors, and Clinical Implications

OBJECTIVES

Aseptic bone flap resorption (ABFR) is a known complication of cranioplasty (CP) with an autologous bone flap. The incidence of ABFR has been reported to be as high as 34.2% in the literature; however, it is underestimated in clinical fields. We retrospectively reviewed 13 years of clinical cases of patients who underwent CP after decompressive craniectomy (DC) to investigate the incidence and risk factors of ABFR.

METHODS

Ninety-one patients who underwent DC and CP in Guro Hospital, Korea University Medical Center, were enrolled. ABFR was defined using serial brain computed tomography. To identify possible risk factors for ABFR, univariate and multivariate Cox regression and receiver operating characteristic curve analyses were performed.

RESULTS

Of the 91 patients enrolled, ABFR was diagnosed in 32 patients (35.1%). Bone flap size, existence of a shunting system, and the DC-CP interval were significant in the univariate analysis. Bone flap size was statistically significant in the multivariate analysis (P = 0.0189). The cutoff points of the DC-CP interval and bone flap size were 44 days and 110 cm², respectively.

CONCLUSIONS

The incidence of ABFR was remarkably high. Bone flap size, the existence of a shunting system, and the DC-CP interval were shown to be potential risk factors of ABFR after CP.

Cranioplasty Using a Mixture of Biologic and Nonbiologic Agents

Importance

A surgeon faces challenges with cranioplasty techniques to achieve a successful result with relatively few complications.

Objective

To describe a unique technique for incorporating both biologic autologous bone and nonbiologic allograft materials for defect coverage in cranioplasty with favorable outcomes and low occurrence of complications.

Design, Setting, and Participants

A retrospective medical records review of all 26 patients who underwent primary cranioplasty procedure with a modified technique between January 2011 and December 2015 at a high-volume head and neck oncologic reconstructive practice was conducted; data analysis was also performed during that period. After several years of experience with traditional cranioplasty maneuvers, the modified technique has evolved to incorporate both autologous bone grafts and alloplastic materials in the formation of a shapeable on-lay material. Data were collected on demographics, need for cranioplasty, materials used, outcomes, and risk factors.

Main Outcomes and Measures

Rates of infection, hematoma, flap loss or resorption, cerebrospinal fluid leak, hardware exposure or malfunction, and repeated reconstruction.

Results

Of the 26 patients, 21 (81%) were men; mean (SD) age was 65.8 (14.3) years. Eight (31%) patients had a history of diabetes, 4 (15%) patients were receiving immunosuppressive drugs, and 5 (19%) patients were active smokers at the time of surgery. Neoplasia was the most common cause of the calvarial defect seen, responsible for 20 of 28 (71%) operative defects and necessitated procedures. All but 1 patient achieved successful mineralization following primary cranioplasty with the modified technique; this success was verified based on physical examination and follow-up imaging. Complications were rare and involved only 3 patients who developed postoperative infection; 1 (4%) of these patients lost the integrity of the cranioplasty. Thus, the rate of infection was 11% and loss rate was 4%. Preoperative and postoperative radiotherapy appeared to have no bearing on graft survival.

Conclusions and Relevance

The results using a unique technique for incorporating both biologic autologous bone and nonbiologic allograft materials for defect coverage in cranioplasty are favorable, with satisfactory aesthetic outcomes and limited postoperative complications.

Level of Evidence

4.

Decompressive craniectomy versus craniotomy only for intracranial hemorrhage evacuation: A propensity matched study

BACKGROUND

Decompressive craniectomy (DC) is often performed in conjunction with evacuation of intracranial hemorrhage (ICH) to control intracranial pressure (ICP) in patients with a traumatic brain injury (TBI). The efficacy of DC in lowering ICP is well established; however, its effect on clinical outcomes remains controversial. The aim of our study is to assess outcomes in TBI patients undergoing DC versus craniotomy only (CO) for the evacuation of ICH.

METHODS

We performed a 5-year retrospective analysis of TBI patients with ICH who underwent craniotomy or craniectomy for traumatic ICH. Patients were divided into two groups, those who underwent CO and those who underwent DC. Propensity scoring matched patients in a 1:2 ratio for demographics, admission Glasgow Coma Scale (GCS) score, severity of injury, type and size of ICH, and anticoagulant use. Outcome measures included mortality, adverse discharge disposition (skilled nursing facility), discharge GCS and Glasgow Outcome Scale scores, and complications.

RESULTS

We reviewed 1,831 patients with TBI, of which 155 underwent craniotomy and/or craniectomy. After propensity score matching, we included 99 of those patients in our study (DC, 33; CO, 66). Matched groups were similar in age (p = 0.68), admission GCS score (p = 0.50), Injury Severity Score (p = 0.70), head Abbreviated Injury Scale score (p = 0.32), and intracranial bleeding characteristics. Overall, 26.3% (n = 26) of the patients died and 62.6% (n = 62) were discharged to Rehab/skilled nursing facility. There was no difference in the mortality rate (27.3% vs. 25.0%; p = 0.99), adverse discharge disposition (45% vs. 33%; p = 0.66), GCS score (p = 0.53), and Glasgow Outcome Scale (p = 0.80) at discharge between the DC and the CO groups. However, patients in DC group had higher complication rates and ventilator days.

CONCLUSION

This study showed no significant difference in clinical outcomes for patients undergoing evacuation of ICH regardless of the procedure performed. DC did not appear to be superior to craniotomy alone for the treatment of acute ICH.

LEVEL OF EVIDENCE

Therapeutic, level III.

Predicting posttraumatic hydrocephalus: derivation and validation of a risk scoring system based on clinical characteristics

Posttraumatic hydrocephalus (PTH) is a disorder of disturbed cerebrospinal fluid (CSF) dynamics after traumatic brain injury (TBI). It can lead to brain metabolic impairment and dysfunction and has a high risk of clinical deterioration and worse outcomes. The incidence and risk factors for the development of PTH after decompressive craniectomy (DC) has been assessed in previous studies, but rare studies identify patients with higher risk for PTH among all TBI patients. This study aimed to develop and validate a risk scoring system to predict PTH after TBI. Demographics, injury severity, duration of coma, radiologic findings, and DC were evaluated to determine the independent predictors of PTH during hospitalization until 6 months following TBI through logistic regression analysis. A risk stratification system was created by assigning a number of points for each predictor and validated in an independent cohort. The model accuracy was assessed by the area under the receiver operating characteristic curve (AUC). Of 526 patients in the derivation cohort, 57 (10.84%) developed PTH during 6 months follow up. Age > 50 yrs (Odd ratio [OR] = 1.91, 95% confidence interval [CI] 1.09-3.75, 4 points), duration of coma ≥1 w (OR = 5.68, 95% CI 2.57-13.47, 9 points), Fisher grade III (OR = 2.19, 95% CI 1.24-4.36, 5 points) or IV (OR = 3.87, 95% CI 1.93-8.43, 7 points), bilateral DC (OR = 6.13, 95% CI 2.82-18.14, 9 points), and extra herniation after DC (OR = 2.36, 95% CI 1.46-4.92, 5 points) were independently associated with PTH. Rates of PTH for the low- (0-12 points), intermediate- (13-22 points) and high-risk (23-34 points) groups were 1.16%, 35.19% and 78.57% (p < 0.0001). The corresponding rates in the validation cohort, where 17/175 (9.71%) developed PTH, were 1.35%, 37.50% and 81.82% (p < 0.0001). The risk score model exhibited good-excellent discrimination in both cohorts, with AUC of 0.839 versus 0.894 (derivation versus validation) and good calibration (Hosmer-Lemshow p = 0.56 versus 0.68). This model will be useful to identify patients at high risk for PTH who may be candidates for preventive interventions, and to improve their outcomes.

Impacts of pressure bonding fixation on a bone flap depression and resorption in patients with craniotomy

Fixation of bone flaps after craniotomy is a routine part of every neurosurgical procedure. Common problems encountered are bone flap depression and resorption. Authors performed the pressure-bonding bone flap fixation (PBFF) using absorbable craniofix (AC) and hydroxyapatite wedge (HW). The aim of the present study is to evaluate the efficacy of PBFF to prevent a bone flap depression and resorption in patients treated with craniotomy. Four-hundred fifty-four patients underwent craniotomies. Authors collected the following data: age, sex, type of craniotomy, what kind of surgery, whether bypass surgery was performed, whether surgery was the initial, whether AC and the HW were used, bone flap depression and resorption at 6-month after the craniotomy. PBFF was defined as a bone flap fixation using both AC and HW to impress a bone flap to forehead. The mean age was 62±13years and 404 (89%) patients were women. PBFF was performed in 71 patients (16%), either AC or HW was used in 141 (31%), only AC was used in 116 (25%), and only HW was used in 25 (5.5%). At 6-month after the surgery, a bone flap depression was seen in 38 patients (8.4%), and a bone flap resorption was seen in 66 (15%). Multivariate analysis showed that only a PBBF showed a negative correlation with bone flap depression (p=0.044) and resorption (p=0.011). The results of the present study showed that PBFF reduced a bone flap depression and resorption and provided excellent postoperative cosmetic results.

Cranioplasty with autogenous bone flaps cryopreserved in povidone iodine: a long-term follow-up study

OBJECTIVE The aim of this study was to investigate the long-term therapeutic efficacy of cranioplasty with autogenous bone flaps cryopreserved in povidone iodine and explore the risk factors for bone resorption. METHODS Clinical data and follow-up results of 188 patients (with 211 bone flaps) who underwent cranioplasty with autogenous bone flaps cryopreserved in povidone-iodine were retrospectively analyzed. Bone flap resorption was classified into 3 types according to CT features, including bone flap thinning (Type I), reduced bone density (Type II), and osteolysis within the flaps (Type III). The extent of bone flap resorption was graded as mild, moderate, or severe. RESULTS Short-term postoperative complications included subcutaneous or extradural seroma collection in 19 flaps (9.0%), epidural hematoma in 16 flaps (7.6%), and infection in 8 flaps (3.8%). Eight patients whose flaps became infected and had to be removed and 2 patients who died within 2 years were excluded from the follow-up analysis. For the remaining 178 patients and 201 flaps, the follow-up duration was 24-122 months (mean 63.1 months). In 93 (46.3%) of these 201 flaps, CT demonstrated bone resorption, which was classified as Type I in 55 flaps (59.1%), Type II in 11 (11.8%), and Type III in 27 (29.0%). The severity of bone resorption was graded as follows: no bone resorption in 108 (53.7%) of 201 flaps, mild resorption in 66 (32.8%), moderate resorption in 15 (7.5%), and severe resorption in 12 (6.0%). The incidence of moderate or severe resorption was higher in Type III than in Type I (p = 0.0008). The grading of bone flap resorption was associated with the locations of bone flaps (p = 0.0210) and fragmentation (flaps broken into 2 or 3 fragments) (p = 0.0009). The incidence of bone flap collapse due to bone resorption was higher in patients who underwent ventriculoperitoneal (VP) shunt implantation than in those who did not (p = 0.0091). CONCLUSIONS Because of the low incidence rates of infection and severe bone resorption, the authors conclude that cranioplasty with autogenous bone flaps cryopreserved in povidone-iodine solution is safe and effective. The changes characteristic of bone flap resorption became visible on CT scans about 2 months after cranioplasty and tended to stabilize at about 18 months postoperatively. The bone resorption of autogenous bone flap may be classified into 3 types. The rates of moderate and severe resorption were much higher in Type III than in Type I. The grade of bone flap resorption was associated with bone flap locations. Fragmented bone flaps or those implanted in patients treated with VP shunts may have a higher incidence of bone flap collapse due to bone resorption.

Volume of Brain Herniation in Patients with Ischemic Stroke After Decompressive Craniectomy

BACKGROUND

Decompressive craniectomy procedures are performed in patients with malignant intracranial hypertension. A bone flap is removed to relieve pressure. Later, a second operation is performed to reconstruct the skull after brain swelling has resolved. This surgical treatment would be improved if it were possible to perform a single operation that decompressed the brain acutely and eliminated the need for a second operation. To design a device and procedure that achieve this objective, it is essential to understand how the brain swells after a craniectomy procedure.

METHODS

We identified 20 patients with ischemic stroke who underwent a decompressive hemicraniectomy operation. Skull defect morphology and postoperative brain swelling were measured using computed tomography scan data. Additional intracranial volume created by placing a hypothetical cranial plate implant offset from the skull surface by 5 mm was measured for each patient.

RESULTS

The average craniectomy area and brain herniation volume was 9999 ± 1283 mm² and 30.48 ± 23.56 mL, respectively. In all patients, the additional volume created by this hypothetical implant exceeded the volume of brain herniation observed.

CONCLUSIONS

These findings show that a cranial plate with a 5-mm offset accommodates the brain swelling that occurs in this patient population.

Complications Associated with Decompressive Craniectomy: A Systematic Review

Decompressive craniectomy (DC) has been used for many years in the management of patients with elevated intracranial pressure and cerebral edema. Ongoing clinical trials are investigating the clinical and cost effectiveness of DC in trauma and stroke. While DC has demonstrable efficacy in saving life, it is accompanied by a myriad of non-trivial complications that have been inadequately highlighted in prospective clinical trials. Missing from our current understanding is a comprehensive analysis of all potential complications associated with DC. Here, we review the available literature, we tabulate all reported complications, and we calculate their frequency for specific indications. Of over 1500 records initially identified, a final total of 142 eligible records were included in our comprehensive analysis. We identified numerous complications related to DC that have not been systematically reviewed. Complications were of three major types: (1) Hemorrhagic (2) Infectious/Inflammatory, and (3) Disturbances of the CSF compartment. Complications associated with cranioplasty fell under similar major types, with additional complications relating to the bone flap. Overall, one of every ten patients undergoing DC may suffer a complication necessitating additional medical and/or neurosurgical intervention. While DC has received increased attention as a potential therapeutic option in a variety of situations, like any surgical procedure, DC is not without risk. Neurologists and neurosurgeons must be aware of all the potential complications of DC in order to properly advise their patients.