Syndrome of the Trephined: Quantitative Functional Improvement after Large Cranial Vault Reconstruction

Risk Factors for Seizures After Titanium Cranioplasty: Five-Year Experience from a Single Institution

OBJECTIVE

Seizures are one of the complications that can occur after cranioplasty (CP). In some regions, titanium mesh remains the material of choice for CP. However, risk factors for seizures after titanium CP have been less studied. The purpose of this study was to identify potential risk factors for early seizures (≤7 days) and late seizures (>8 days) after titanium CP in a single institution.

METHODS

A retrospective review was conducted of 241 consecutive patients who received titanium CP at the First Affiliated Hospital of Harbin Medical University from January 2016 to December 2020. Univariate and multivariable logistic regression analyses were performed to determine the independent risk factors for new-onset seizures after titanium CP.

RESULTS

Fifteen patients (6.22%) experienced early post-CP seizures, and late post-CP seizures were observed in 81 patients (33.61%). A flaccid concave cranial defect (P = 0.042) was associated with early post-CP seizures, whereas hypertension (P < 0.001) was the only significant predictor for late seizures after titanium CP.

CONCLUSIONS

Seizure is a common complication after titanium CP, especially in patients who do not receive prophylactic antiepileptic drugs before the procedure. Risk factors for new-onset seizures at different periods after titanium CP were found to be different. In addition, radiologic factors before titanium CP may play a role in early new-onset seizures after titanium CP and should not be ignored.

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.

Custom 3D-Printed External Cranial Orthotic for Prevention and Treatment of Syndrome of the Trephined

Syndrome of the Trephined (SoT) is a frequently misunderstood and underdiagnosed outcome of decompressive craniectomy, especially in cases of trauma. The pressure gradient between atmospheric pressure and the sub-atmospheric intracranial pressure results in a sinking of the scalp overlying the craniectomy site. This gradually compresses the underlying brain parenchyma. This parenchymal compression can disrupt normal autoregulation and subsequent metabolism, yielding symptoms ranging from headaches, dizziness, altered behavior to changes in sensation, and difficulty with ambulation, coordination, and activities of daily living. We present a case of SoT treated with a 3D-printed custom polycarbonate external cranial orthotic that allowed us to re-establish this pressure gradient by returning the cranium to a closed system. The patient demonstrated subjective improvement in quality of life and his symptoms. This was consistent with the re-expanded brain parenchyma on CT imaging.

Optimal Timing of Cranioplasty and Predictors of Overall Complications After Cranioplasty: The Impact of Brain Collapse

BACKGROUND

The optimal timing of cranioplasty (CP) and predictors of overall postoperative complications are still controversial.

OBJECTIVE

To determine the optimal timing of CP.

METHODS

Patients were divided into collapsed group and noncollapsed group based on brain collapse or not, respectively. Brain collapse volume was calculated in a 3-dimensional way. The primary outcomes were overall complications and outcomes at the 12-month follow-up after CP.

RESULTS

Of the 102 patients in this retrospective observation cohort study, 56 were in the collapsed group, and 46 were in the noncollapsed group. Complications were noted in 30.4% (n = 31), 24 (42.9%) patients in the collapsed group and 7 (15.2%) patients in the noncollapsed group, with a significant difference ( P = .003). Thirty-three (58.9%) patients had good outcomes (modified Rankin Scale 0-3) in the collapsed group, and 34 (73.9%) patients had good outcomes in the noncollapsed group without a statistically significant difference ( P = .113). Brain collapse ( P = .005) and Karnofsky Performance Status score at the time of CP ( P = .025) were significantly associated with overall postoperative complications. The cut-off value for brain collapse volume was determined as 11.26 cm 3 in the receiver operating characteristic curve. The DC-CP interval was not related to brain collapse volume or postoperative complications.

CONCLUSION

Brain collapse and lower Karnofsky Performance Status score at the time of CP were independent predictors of overall complications after CP. The optimal timing of CP may be determined by tissue window based on brain collapse volume instead of time window based on the decompressive craniectomy-CP interval.

Mesenchymal Stem Cells Combined with a P(VDF-TrFE)/BaTiO3 Scaffold and Photobiomodulation Therapy Enhance Bone Repair in Rat Calvarial Defects

BACKGROUND

Tissue engineering and cell therapy have been the focus of investigations on how to treat challenging bone defects. This study aimed to produce and characterize a P(VDF-TrFE)/BaTiO₃ scaffold and evaluate the effect of mesenchymal stem cells (MSCs) combined with this scaffold and photobiomodulation (PBM) on bone repair.

METHODS AND RESULTS

P(VDF-TrFE)/BaTiO₃ was synthesized using an electrospinning technique and presented physical and chemical properties suitable for bone tissue engineering. This scaffold was implanted in rat calvarial defects (unilateral, 5 mm in diameter) and, 2 weeks post-implantation, MSCs were locally injected into these defects (n = 12/group). Photobiomodulation was then applied immediately, and again 48 and 96 h post-injection. The μCT and histological analyses showed an increment in bone formation, which exhibited a positive correlation with the treatments combined with the scaffold, with MSCs and PBM inducing more bone repair, followed by the scaffold combined with PBM, the scaffold combined with MSCs, and finally the scaffold alone (ANOVA, p ≤ 0.05).

CONCLUSIONS

The P(VDF-TrFE)/BaTiO₃ scaffold acted synergistically with MSCs and PBM to induce bone repair in rat calvarial defects. These findings emphasize the need to combine a range of techniques to regenerate large bone defects and provide avenues for further investigations on innovative tissue engineering approaches.

Osteoprotegerin-eluting nanoparticulate mineralized collagen scaffolds improve skull regeneration

Custom synthesis of extracellular matrix (ECM)-inspired materials for condition-specific reconstruction has emerged as a potentially translatable regenerative strategy. In skull defect reconstruction, nanoparticulate mineralized collagen glycosaminoglycan scaffolds (MC-GAG) have demonstrated osteogenic and anti-osteoclastogenic properties, culminating in the ability to partially heal in vivo skull defects without the addition of exogenous growth factors or progenitor cell loading. In an effort to reduce catabolism during early skull regeneration, we fabricated a composite material (MCGO) of MC-GAG and recombinant osteoprotegerin (OPG), an endogenous anti-osteoclastogenic decoy receptor. In the presence of differentiating osteoprogenitors, MCGO demonstrated an additive effect with endogenous OPG limited to the first 14 days of culture with total eluted and scaffold-bound OPG exceeding that of MC-GAG. Functionally, MCGO exhibited similar osteogenic properties as MC-GAG, however, MCGO significantly reduced maturation and resorptive activities of primary human osteoclasts. In a rabbit skull defect model, MCGO scaffold-reconstructed defects displayed higher mineralization as well as increased hardness and microfracture resistance compared to non-OPG functionalized MC-GAG scaffolds. The current work suggests that MCGO is a development in the goal of reaching a materials-based strategy for skull regeneration.

[Surgical treatment of patients with skull defects and cerebrospinal fluid flow disorders after previous decompressive craniectomy]

Decompressive craniectomy (DC) is performed for refractory intracranial hypertension following severe traumatic brain injury, vascular and oncological diseases. This fact increases the number of patients with extensive and giant skull defects. Cerebrospinal fluid (CSF) flow disorders after DC are often accompanied by ventriculomegaly. However, only some patients with ventriculomegaly have hydrocephalus and require CSF bypass procedures. Differentiation of post-traumatic hydrocephalus requiring surgical treatment and atrophic dilation of ventricular system «ex vacuo» caused by brain injury is still an important issue. Skull sealing as a way to normalize CSF circulation and eliminate hydrocephalus is also an open question. Currently, there is no unified approach to patients with extensive and giant cranial defects combined with post-traumatic hydrocephalus. There is no unified algorithm for sequence of reconstructive and CSF bypass operations in these patients. Literature data on risks of infectious complications for different surgical strategies are controversial.

An Algorithm for Reconstruction of Electrical Injuries of the Scalp

BACKGROUND

Electrical injuries of the scalp are a frequent occurrence in developing countries. Burns can be contact or conductive and result in extensive tissue damage. The authors present their experience with treatment of scalp and calvarial electrical injuries and propose a management algorithm.

METHODS

This was a retrospective cohort study comprising all patients with electrical injuries of the scalp treated at the authors' center between January of 2010 and December of 2016. Noncontrast computed tomography scans were obtained to assess viability of the calvarium in patients who presented more than 2 weeks after injury. Single-stage débridement and reconstruction were performed. All nonviable soft tissue and bone was removed. Soft-tissue reconstruction was performed with skin grafts, local scalp flaps, pedicled trapezius flaps, and free flaps (anterolateral thigh, latissimus dorsi, and scapular). Cranioplasty was performed in a delayed manner with autologous bone grafts.

RESULTS

Over a 7-year period, a total of 52 patients underwent scalp reconstruction for high-voltage (44 patients) and low-voltage (eight patients) electrical injury. All patients underwent successful soft-tissue reconstruction. Osteomyelitis with draining sinuses developed in three patients; these patients underwent flap re-elevation and bone débridement, which resulted in a healed wound and stable reconstruction. Cranioplasty was performed with split calvarial grafts in two patients and split rib grafts in four patients. One patient underwent scalp tissue expansion for hair restoration.

CONCLUSION

The authors propose an algorithm for reconstruction of electrical injuries of the scalp. Thorough débridement of the calvarium is the most important determinant of a successful outcome.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

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.

Low-Cost Cranioplasty—A Systematic Review of 3D Printing in Medicine

The high cost of biofabricated titanium mesh plates can make them out of reach for hospitals in low-income countries. To increase the availability of cranioplasty, the authors of this work investigated the production of polymer-based endoprostheses. Recently, cheap, popular desktop 3D printers have generated sufficient opportunities to provide patients with on-demand and on-site help. This study also examines the technologies of 3D printing, including SLM, SLS, FFF, DLP, and SLA. The authors focused their interest on the materials in fabrication, which include PLA, ABS, PET-G, PEEK, and PMMA. Three-dimensional printed prostheses are modeled using widely available CAD software with the help of patient-specific DICOM files. Even though the topic is insufficiently researched, it can be perceived as a relatively safe procedure with a minimal complication rate. There have also been some initial studies on the costs and legal regulations. Early case studies provide information on dozens of patients living with self-made prostheses and who are experiencing significant improvements in their quality of life. Budget 3D-printed endoprostheses are reliable and are reported to be significantly cheaper than the popular counterparts manufactured from polypropylene polyester.

Decompressive Craniectomy vs. Craniotomy Only for Traumatic Brain Injury: A Propensity-Matched Study of Long-Term Outcomes in Neuropsychology

Background

Both decompressive craniectomy (DC) and craniotomy only (CO) are commonly performed to treat patients with traumatic brain injury (TBI) by evacuation of intracranial hemorrhage (ICH) and control intracranial pressure (ICP). The outcomes of these two procedures have been well-studied; however, most research studies have focused on physical functions. The purpose of our study is to assess long-term outcomes in neuropsychology after DC or CO in TBI patients.

Methods

Information was collected from patients with TBI who had undergone DC or CO and were then in the postoperative stable phase (6–24 months after injury). Propensity scoring matched the patients in a 1:1 ratio for demographics, cause of injury, TBI subtype, TBI severity, computed tomography (CT) findings, surgery side, and interval from TBI. We used Wechsler Adult Intelligence Scale-Chinese Revision (WAIS-RC), Wechsler Memory Scale-Chinese Revision (WMS-RC), Physical Self-maintenance Scale (PSMS), Instrumental Activities of Daily Living Scale (IADL), and Glasgow Outcome Scale-Extended (GOSE) to measure the long-term outcomes in TBI patients, especially in neuropsychology.

Results

There were 120 TBI patients included in our study. After matching, 74 patients were paired into the DC group (n = 37) and the CO group (n = 37). There were no differences in the gender (P = 1.000), age at injury (P = 0.268), marital status (P = 0.744), pre-injury employment (P = 0.711), comorbidities (P = 1.000), education level (P = 0.969), cause of injury (P = 0.357), TBI subtype (P = 0.305), Glasgow Coma Scale (GCS) total score (P = 0.193), unconsciousness (P = 0.485), traumatic subarachnoid hemorrhage (tSAH) (P = 0.102), unresponsive pupil (P = 1.000), midline shift (P = 0.409), cisterns compressed or absent (P = 0.485), surgery side (P = 0.795), and interval from TBI (P = 0.840) between the two groups. The CO group was associated with better cognitive function in WAIS-RC OIQ (P = 0.030) and WAIS-RC FIQ (P = 0.021) and better daily function in IADL (P = 0.028) and ADL total (P = 0.030). The DC group also had a lower GOSE (P = 0.004) score compared to the CO group. No difference was observed in WAIS-VIQ (P = 0.062), WMS-RC MQ (P = 0.162), and PSMS (P = 0.319).

Conclusion

In the matched cohort, patients who underwent CO had better long-term outcomes in cognitive and daily function compared with DC. Future randomized control trials are needed for intensive studies on physical and neuropsychological prognosis in TBI patients.

A Narrative Review of Cell-Based Approaches for Cranial Bone Regeneration

Current cranial repair techniques combine the use of autologous bone grafts and biomaterials. In addition to their association with harvesting morbidity, autografts are often limited by insufficient quantity of bone stock. Biomaterials lead to better outcomes, but their effectiveness is often compromised by the unpredictable lack of integration and structural failure. Bone tissue engineering offers the promising alternative of generating constructs composed of instructive biomaterials including cells or cell-secreted products, which could enhance the outcome of reconstructive treatments. This review focuses on cell-based approaches with potential to regenerate calvarial bone defects, including human studies and preclinical research. Further, we discuss strategies to deliver extracellular matrix, conditioned media and extracellular vesicles derived from cell cultures. Recent advances in 3D printing and bioprinting techniques that appear to be promising for cranial reconstruction are also discussed. Finally, we review cell-based gene therapy approaches, covering both unregulated and regulated gene switches that can create spatiotemporal patterns of transgenic therapeutic molecules. In summary, this review provides an overview of the current developments in cell-based strategies with potential to enhance the surgical armamentarium for regenerating cranial vault defects.

Trepanations in the ancient Greek colony of Akanthos: Skull surgery in the light of Hippocratic medicine

OBJECTIVE

The study presents seven new cases of trepanations on four individuals from the ancient Greek colony of Akanthos (5th - 1st c. BC) and juxtaposes the paleopathological observations with the Hippocratic treatises.

MATERIALS

A meta-analysis of 42 published trepanations on 27 individuals from Greece.

METHODS

Trepanations from Akanthos were observed macroscopically, stereoscopically and by computer tomography. The meta-analysis considers the demographic, geographical and temporal distribution, the techniques, associated pathology, and survival rate.

RESULTS

Trepanations were observed on four females in Akanthos. Three trepanations were performed with scraping and four with drilling. Two individuals exhibited significant signs of healing, and two survived shortly after the operation. In two cases, trepanation was practiced for treating cranial injuries. In Greek antiquity trepanation was performed predominantly in males, principally as a surgical treatment of cranial injuries. The survival rate was 62.9 %. Scraping was the oldest, most frequent and successful technique.

CONCLUSIONS

Trepanation performed systematically in Greece since the Bronze Age (ca. 2,000 BC). Hippocrates who rationally conceived medicine, codified the pre-existing empirical knowledge. The trepanations from Akanthos show technical similarities but also discrepancies from the Hippocratic recommendations, confirming the mental and technical readiness of the ancient surgeon.

SIGNIFICANCE

The synchronous to Hippocrates trepanations from Akanthos, provide the opportunity to compare physical evidence with the written sources.

LIMITATIONS

The frequency of trepanations is affected by the representativeness and the state of the skeletal preservation.

SUGGESTIONS FOR FUTURE RESEARCH

Trepanations published in previous decades, need to be reassessed with new imaging modalities. A standard recording methodology is fundamental for data comparison.

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.

Decision-Making in Adult Cranial Vault Reconstruction

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Define and classify different types of cranial defects 2. Compare both autologous and alloplastic options for reconstruction 3. Develop an optimal approach for cranial vault reconstruction in various clinical scenarios.

SUMMARY

Defects of the cranium result from various causes, including traumatic loss, neurosurgical intervention, skull tumors, and infection. Cranial vault reconstruction aims to restore both the structural integrity and surface morphology of the skull. To ensure a successful outcome, the choice of appropriate cranioplasty reconstruction will vary primarily based on the cause, location, and size of the defect. Other relevant factors that must be considered include adequacy of soft-tissue coverage, presence of infection, and previous or planned radiation therapy. This article presents an algorithm for the reconstruction of various cranial defects using both autologous and alloplastic techniques, with a comparison of their advantages and disadvantages.

Unrepaired decompressive craniectomy worsens motor performance in a rat traumatic brain injury model

Decompressive craniectomy (DC) is often required to manage rising intracranial pressure after traumatic brain injury (TBI). Syndrome of the trephine (SoT) is a reversible neurologic condition that often occurs following DC as a result of the unrepaired skull. The purpose of the present study is to characterize neurological impairment following TBI in rats with an unrepaired craniectomy versus rats with a closed cranium. Long Evans male rats received a controlled cortical impact (CCI) over the caudal forelimb area (CFA) of the motor cortex. Immediately after CCI, rats received either a hemi-craniectomy (TBI Open Skull Group) or an immediate acrylic cranioplasty restoring cranial anatomy (TBI Closed Skull Group). Motor performance was assessed on a skilled reaching task on post-CCI weeks 1—4, 8, 12, and 16. Three weeks after the CCI injury, the TBI Closed Skull Group demonstrated improved motor performance compared to TBI Open Skull Group. The TBI Closed Skull Group continued to perform better than the TBI Open Skull Group throughout weeks 4, 8, 12 and 16. The protracted recovery of CFA motor performance demonstrated in rats with unrepaired skulls following TBI suggests this model may be beneficial for testing new therapeutic approaches to prevent SoT.