Good morning, everyone. I'm Joe Gracioli speaking from the University of Miami. Thanks for the invitation for this module. And let's talk a little bit about cranial reconstruction. It's interesting to see how things have evolved. Let's compare to what they did back in 1869. There's a very interesting report from Dr. Harlow that described the case of a patient that was injured during a work-related accident. A metal bar went through the head and brain in a transfixating injury. The bar was removed, the patient was dressed, and then conservative care was basically applied. A brain abscess spontaneously drained through the outer, through the upper part of this injury after two weeks. On the 64th day, he was treated. He was bled in around 16 ounces. He recovered eventually. And actually, he regained independency for his daily activities. But he definitely had a change in personality and cognition. Unfortunately, 12 years later, he died of status epilepticus. I enjoyed to read the report that they described this as vis conservatrix. And I dressed him, and God healed him. Well, now I'd like to present a case of this patient, 40 years old, male, that came to our emergency department. He was stabbed in the left eye, as you can see in the image here. The penetrating injury destroyed the medial and superior orbital walls. The knife crossed both frontal lobes, causing hemoventrical and interparenchymal contusions. Unfortunately, the patient was very critical because of the systemic injuries, and went straight to an exploratory laparotomy to treat the interabdominal hemorrhages, and had chest tube placed. He had a GCS of 4 when he arrived with preserved brain stem reflexes. And after the initial condition was stabilized, he was taken to further studies to assess the degree of vascular injury. Upon completion of CTA, we could see in the bone window here in more details the extension of the orbital injuries. Given the penetrating injury by the CTA, given the penetrating injury by a blade, the suspicion of vascular injuries was very high. Unfortunately, no injury could be detected on the initial CTA. Given the high suspicion, he was taken to a DSA that presented findings compatible to pseudoaneurysms on the right anterior cerebral artery. On the same session, those findings were treated with the sacrifice of the vessel, as no stenting or flow diversion was possible. In a 3D reconstruction, we can appreciate the defect once again, and after the embolization, we see here the findings, and we didn't see any larger infarct encompassing the motor area. Clinically, he was recovering, he was still able to move both legs, showing thankfully no repercussion of the embolization. The patient was then taken for a cranial reconstruction, when systemically better, and the vascular injuries were treated. By means of a bicoronal incision, we created a large pericranial flap here, as you can see in this image. Using four boreholes, one on each side of the sagittal sinus, and one of each keyhole, bilateral exposure was performed. You can see here the cranial edges of the craniotomy, the dura was exposed, and here the sagittal sinus. This intraoperative video can show here in more details the defect, which was very extensive in the orbital roof, and the dissection that was performed to release the sagittal sinus from the crista galli, exposing the contralateral orbital roof that was necessary for us to perform the reconstruction of the damaged orbital roof. Now you can see here, we're retracting the dura, this is the right orbital roof, and here is where the superior sagittal sinus was detached, and here you see the defect. The craniotomy flap was used for the reconstruction, it was split and harvested the bone graft to be used to be reconstructed. Navigation was also applied because it was important not only to reconstruct the orbital roof and repair the dural defect, but also to perform an extensive debridement as this was a penetrating injury with infection associated. The navigation showed that by means of the bifrontal craniotomy we could reach the bottom of the orbital cavity, cleaning the debris from the initial injury. After hemostasis was performed, the pericranial flap was still left on top of the skin flap, the bone graft that was created was adjusted to fit into the space that was created by the lesion. We can see here that the graft was tied in both sides to be kept in place and after this was accomplished, the large pericranial graft was placed between the bone and the dura, going past the bony reconstruction all the way until the planum sphenoidale close to the clinoids. Ultimately, the defect was the pericranial flap was repositioned. In the post-operative CT, we can see here the position of the bone graft that was not able to reach further posterior, given the degree of brain retraction that would be necessary, but the graft was placed all the way until there, treating the CSF leak. The patient continued to be treated from his brain infection with wide-spectrum antibiotics and antifungal agents. Nevertheless, as you can see here in the images, the abscess progressed to increase, especially on the left side. Therefore, we repeated images and we prepared for the drainage. The patient was taken to the OR for a second time to treat this fluid that built up in different pockets here on the left frontal lobe. As he had a bicoronal, bifrontal craniotomy, we chose to use a frameless system and the drainage was successful. So now talking a little bit in general about cranial reconstruction. Why? When? And how to do it? Well, let's start with the why. Since the Brain Trauma Foundation guidelines were updated based on the last data from the last analysis of the RESQ-ICP trial, a new recommendation came out which is the secondary decompression performed for late refractory ICP elevation is now recommended to improve mortality and to improve functional outcomes. And most of the patients that were analyzed on this trial, they underwent a bifrontal temporal decompression. This is interesting because with a larger number of decompressions being performed, proportionally we're going to have more cases with syndrome of the trephine that we know that occurs in around a third of the patients that undergo a major craniotomy, decompressive craniotomy. We know that this has, the occurrence of the syndrome has relationship with the size of the decompression and to be successful we typically need a wide decompression. This study showed that the symptoms of the syndrome of the trephine, typically they are more pronounced around 4.5 months after the decompression. On the other hand, the time to improve from the symptoms is typically very short, but can take up to six weeks. It's interesting to mention that no correlation with the type of reconstruction and the symptoms improvement was detected. So pointing to the fact that once you can relieve the brain from the direct action of the gravity, the symptoms tend to improve. It's interesting to mention as well that almost all of the patients improved somehow, talking about cognition and independent functioning. The vast majority improved even completely. It's very interesting. In all domains, if we look here, orientation, comprehension, judgment, memory, it was significant as well as functional independency was also very pronounced. Now regarding the time for the reconstruction, most of the studies commonly show the reconstruction being performed around three months after the decompression. There is evidence suggesting that early cranioplasty could bring a better functional outcome with no increased complication rates. Even a study from China showed that it could be feasible, the reconstruction, in the first two months, and would be indicated with a reasonable complication rate for patients with obvious defects and syndrome of the trephine, with GCS equal and superior to nine. But it's interesting to see that even a later cranioplasty can still bring benefits regarding cognition and functionality if it is performed around six months after the defect was created. In this study, it was exactly addressing the question if there is an optimal time to perform the reconstruction. In this study, they compared 25 patients that underwent the reconstruction before two weeks and 45 after 12 weeks, before 12 and after 12. And no difference in infection and in hydrocephalus rates were observed. On the other hand, with a much larger cohort of patients with over 3,000 patients that underwent early versus late reconstruction, when we say early, we say before three months. So it showed that doing this before three months, this would increase the risk for hydrocephalus. But in fact, for other complications like motor deficits or infections, would not be increased. So we spoke why to do the reconstruction, to mitigate the symptoms of syndrome of the trephine, and also to improve mechanical protection. We spoke about timing. Typically, after three months would be the recommendation of the largest studies. And now how to do the reconstruction. So different materials can be used. We could separate first into biological and synthetic. Definitely, the autografts are the gold standard, meaning to replace the patient's bone flap would be the best treatment to reconstruct the defect. Historically, even channel grafts or allografts were used. And when the autograft is not available, different materials could be used. We're going to see in detail in the next few slides. So researching into the trends. So when you have an infection, as in the case we presented in the beginning of the talk, we'd rather not use foreign bodies. Therefore, orthologous grafts would be ideal. When you're able to, and especially in cases when you're planning to do frontal orbital craniotomy, it's interesting to use, for example, the PMMA. In this paper, they show how they were planning the craniotomy in advance with the help of navigation. And after it was done, the reconstruction was done with a pre-built implant. In cases when we have the defect already before the surgery, like this patient that underwent previous craniotomy here and had resorption of the part of the bone flap, this Italian study was showing the application of the MRI merged with CT for segmentation creation of a 3D model. This is FDA approved as well. We can use here in the US. The 3D printer was used to create a model, like a mold, which was done in-house, therefore 10 times less expensive. And the mold was used to create the PMMA procedure. When talking about the reconstruction, there are different techniques to mitigate the need for it. For example, this use of a hinge craniotomy for cerebral decompression that was developed in West Virginia. The patients that required the decompression, the bone flap was left in situ with the use of a hinge, as they call, with this titanium mini plate. And as the edema subsided, the bone flap was sitting closer, and then the final fixation could be done percutaneously. In-situ floating resin cranioplasty for cerebral decompression is also an option, as we can see here from this interesting study from this group in Korea, in which they, for the decompression, once the craniotomy was performed, they used a resin-based plate, which was loosely fixated to the skull, like widely, with silk ties. And it was done intentionally broader than the defect. And as the edema subsided, what happened is that this was going closer and ultimately being attached to the cranial defect. It's an interesting strategy as well. Two other materials that can be used for the cranial reconstruction are peak and titanium, as in our spine cases, we typically have peaks and titanium cages. So the peak is optimal when you need a very detailed reconstruction, typically frontal orbital, as you see here, what can be prepared before the procedure. It's the most expensive one and has limited osseointegration. Also, it's prone to dislodgement and infection for the same reasons. On the other hand, titanium is not as expensive and has great osseointegration, hence less mobility and it's less prone to infections. Different materials with different properties can be described, including this one with a clear surface that is amenable to transcranial duplex studies. This could be interesting in patients that undergo vascular reconstruction like anastomosis and need frequent vascular images to follow up the grafting. Also, this is interesting to use for patients that require a VP shunt in which a small craniectomy is performed. This process is implanted into the skull, creating a low profile where the reservoir can be implanted. When we take a patient for a cranial reconstruction and we know that the patient has a sunken flap, we typically don't anticipate issues with intracranial pressure. But in patients when the defect is not sunken, as in this kid, for example, we have concerns about postoperative hydrocephalus, among other symptoms that could lead to an unfavorable surgical outcome. Thinking about it, this group of authors developed an integrated wireless intracranial pressure monitor device that was coupled to the reconstruction flap. This was able to show the postoperative variation in intracranial pressure, giving insight if the patient would be tolerating or not the implant. So this picture depicts what we're talking about. You see the clear implant was coupled to the invasive intracranial monitor, which was read by telemetry. So right after it was implanted in the OR, they had the reading with a normal intracranial pressure. And this could be followed by telemetry in the days that succeeded the reconstruction. And hence, the patient had a good outcome tolerating the implant. So the approach with the clear implant PMMA-based was further studied in this series of consecutively 55 patients, and it showed to be a good option for patients that require more sonolucency, as in vascular patients that we mentioned before. Now talking about some complications and common concerns with the bone reconstruction. This article suggested that late cranioplasty would be more associated with bone resorption. This other one, early cranioplasty. But in fact, most of studies, they did not correlate timing for the reconstruction with the occurrence of the aseptic osteonecrosis or bone resorption. So some might say the way you conserve your bone flap would have an influence if it is stored under a low temperature of around minus 80 degrees Celsius, as we typically do, or in the subcutaneous tissue, as it was historically done. Despite the fact that it might be more adequate in terms of comfort and sterility, since this is associated with 20% of infection rate, in fact, the literature failed to show any open, any evident benefit of one method over the other. Regarding hydrocephalus, two systematic reviews showed an increased hydrocephalus if the cranioplasty is performed before three months, increased risk. This is likely related to the occurrence of the hydrocephalus within this time frame, because it only makes sense if you give more time, the hydrocephalus could spontaneously resolve, and also we could have more of a time frame to detect and to act upon it. Then one might argue that, well, since the patient is going for a general anesthesia for the reconstruction, why not to do a simultaneous v-patient implant and the reconstruction? So these authors, they looked exactly into this question and performed a retrospective review of 51 patients that underwent simultaneous procedures, and as conclusion, they pointed out that cranioplasty and v-patient placement at the same time had a higher complication rate, significantly higher than when they were performed separately. Those findings were corroborated by this Chinese group, in which 32 patients underwent staged compared to simultaneous cranioplasty and v-patient in 17. So again, the effect of the simultaneous shunt and cranioplasty was significantly more associated with complications when compared to the staged procedure. But the question remains apparently open, as this group published last year a series of 40 patients from the University of Illinois in Chicago that underwent simultaneous shunting and reconstruction, as they recommend to do so simultaneously because they pointed to a much lower infection rate associated. There are also groups that don't implant a v-patient in the setting of hydrocephalus, and patients undergoing cranial reconstruction. What this article, for example, describes is the use of ultrasound-guided ventricular puncture. This was published last year from the University of Philadelphia, in which they performed the ventricular puncture, leaving the catheter as a post-operative drain, like an EVD, for a week or so, and ultimately the patients that don't require it, in which it remains clamped and they tolerate, it's removed and the patient remains shunt-free. The group reported on good results using this strategy. Although there was one patient with one infection and another one with a post-cranioplasty v-patient placement after the trial period, but most of the patients were able to remain shunt-free, and as they hypothesized that replacing the bone flap could help to balance the dynamics into the CSF flow. In summary, throughout the talk we saw reasons to perform the cranial reconstruction, including cosmetic, mechanical protection, and especially to correct the syndrome of the tryphine that may occur in one-third of the patients, and when it does, they typically present an important improvement in cognition and functionality. Early versus late is debatable, but typically after three months is recommended because of the lower incidence of hydrocephalus. If you do the shunt in advance or simultaneously, it's controversial, but most authors prefer to do the shunting before the reconstruction, remembering that it's also possible to be done intraoperatively with just an EVD left for post-operative drainage. And the use of autograft whenever possible is typically better because of the integration and infection profile and costs, and when it's not available or in the case of a much more complex defect that needs to be customized, peak autografts are interesting, and also titanium are the two most used to perform the reconstruction, since titanium has a good integration and low infection rates profile. I'd like to thank you all for taking the time and watching the presentation. I hope you could see one or two new points at least, and let's keep in touch.

cranial reconstruction

brain abscess

pseudoaneurysms

pericranial flap

post-operative complications

materials for reconstruction