Background Due to the lack of high-quality evidence which has hindered the development of evidence-based guidelines, there is a need to provide general guidance on cranioplasty (CP) following traumatic brain injury (TBI), as well as identify areas of ongoing uncertainty via a consensus-based approach. Methods The international consensus meeting on post-traumatic CP was held during the International Conference on Recent Advances in Neurotraumatology (ICRAN), in Naples, Italy, in June 2018. This meeting was endorsed by the Neurotrauma Committee of the World Federation of Neurosurgical Societies (WFNS), the NIHR Global Health Research Group on Neurotrauma, and several other neurotrauma organizations. Discussions and voting were organized around 5 pre-specified themes: (1) indications and technique, (2) materials, (3) timing, (4) hydrocephalus, and (5) paediatric CP. Results The participants discussed published evidence on each topic and proposed consensus statements, which were subject to ratification using anonymous real-time voting. Statements required an agreement threshold of more than 70% for inclusion in the final recommendations. Conclusions This document is the first set of practical consensus-based clinical recommendations on post-traumatic CP, focusing on timing, materials, complications, and surgical procedures. Future research directions are also presented.

Background Role of decompressive craniectomy in reducing intracranial pressure is well established. However, it comes with a cost of requiring a second surgery in the form of cranioplasty without which unacceptable hemodynamic consequences occur. It is generally felt that a credible alternative is required.Objective The aim of the study is to devise a mathematical model, which closely represents the cranium and intracranial contents, on which various alternatives can be evaluated with reproducible results, and to work out the effects of a novel technique of expansive cranioplasty on that model. Methods A mathematical model was designed based on the presumption that dura forms a watertight bag-containing brain, floating in cerebrospinal fluid (CSF). A model for an expansive cranioplasty was designed, and its ability to provide the space required to allow volume expansion and to achieve adequate reduction in intracranial pressure (ICP) was evaluated on this model. Results The mathematical model could closely reproduce the surface area-volume relationships in the published literature. Based on the calculations on the model, it was found that a projection of dural outpouching of 0.83 cm beyond the craniectomy margin on either side of a bilateral 12 Â 15 cm elliptical craniectomy defect is required to achieve and accommodate a volume expansion of 157 cm 3 , which was recorded to be the maximum volume expansion in the reviewed literature. A two-step step-ladder cranioplasty can be constructed to achieve an increase in cranial width by 1.1 to 1.3 cm on each side. Conclusion Calculations based on the present model indicate that a two-step expansive cranioplasty can accommodate adequate volume expansion while alleviating the ill effects of a craniectomy and necessity of a second surgery. However, these are discussions on mathematical model, based on multitude of assumptions and approximations, and hence these discussions require clinical trials to validate the findings.

Background Recently, a concept of an “expansive cranioplasty” was forwarded as a feasible single-step alternative to performing a decompressive hemicraniectomy followed by cranioplasty at a later date. Materials and Methods Procedure of single-step step ladder expansive cranioplasty following craniotomy with removal of subdural hematoma (SDH) was done in a case of acute SDH at our center. The author presents the clinical presentation, operative steps, pre- and postoperative neuroimagings, and outcome of the case. Results Postoperative NCCT of the head film showed an increase in biparietal diameter by 10 mm. Measured from the craniectomy margin, the distance of the inner table of the bone was 2.81 mm. Preoperative midline shift of 10.2 mm reduced to 7.9 mm, whereas the GCS improved from E1VTM3 to E2VTM5 in the immediate postoperative period. On his review at the end of 3 months, the patient had no surgery-related complication. Conclusion “Step ladder expansive cranioplasty” has a promise and deserves a trial in more number of cases. If proven acceptable, it can be especially useful for patients for whom coming back for a second surgery may not be all that easy.

Context: Decompressive hemicraniectomy (DC) is the final surgical remedy for refractory raised intracranial pressure (ICP). Even with years of experience and profound refination of technique, the procedure has less rewarding results in traumatic brain injury (TBI). Besides, arrangements for bone flap preservation and the necessity of follow-up surgery in the form of cranioplasty bring in unavoidable monetary and logistic burdens to the patients. Step-ladder expansive cranioplasty was conceptualized as an alternative to achieve adequate intracranial volume expansion to help normalize ICP, with immediate reinstitution of the Monro-Kellie doctrine. It is also expected to prevent cerebral cortical pressure injury to the cortex underlying the craniectomy defect. The evolution of this concept, as worked out on different models, the surgical technique, and our experience with this technique are discussed in this article. Evidence Acquisition: Multiple research projects undertaken by our team to build up the concept and acquire data necessary to plan the surgical procedure have been published over last eight years. This review article attempts to evaluate the existing knowledge and our clinical experience so far. Results: Step-ladder expansive cranioplasty allows an assured centrifugal displacement of the inner table and underlying dural bag at craniotomy site by at least 9 mm, thereby achieving a minimum volume expansion of 120 cc. Both of these parameters can be increased as desired, if considered necessary by the surgeon. Conclusions: Step-ladder expansive cranioplasty offers an alternative that takes the centripetal pressure exerted by the combination of the tensile strength of the scalp and atmospheric pressure off the brain surface while achieving an assured augmentation of intracranial volume that can be optimized on a case-to-case basis, based on our future understanding of the subject. While it can be a single-stage surgery for those satisfied with the cosmesis, a revision cranioplasty (if required) will be easier, cheaper, and cosmetically superior to achieving cover over a craniotomy defect routinely done after DC.

The pathophysiology of malignant intracranial hypertension is a deleterious cycle of increased intracranial pressure, decreased tissue perfusion, declining intracellular energy production, increasing cellular edema, and subsequent increasing intracranial pressure. Decompressive craniectomy offers an effective treatment for intracranial hypertension that is refractory to standard medical treatment. There is no standardized technique suggested for durotomy and expansile duraplasty till date. We conducted this study on a model designed from locally available materials to objectively quantify the volume expansion achieved by the various durotomy and expansion duraplasty techniques. Amongst the more popularly used techniques for durotomy and duraplasty, the apparent volume expansion achieved appears to be maximum with a horse shoe shaped incision (43 ml) as opposed to a cruciate (30 ml) or a multipinnate (36 ml) incision. However, after correcting for the volume of the outpouchings, horse shoe shaped incision looses much of it's sheen (10 cm) lagging far behind the other two duraplasty techniques. Our study has proven the generally held view that there is not much to choose from between the cruciate and multipinnate durotomy techniques in performing expansile duraplasty. A horse shoe shaped durotomy on the other hand appears to be far less fruitful.