A prospective study of computer-aided design and manufacture of titanium plate for cranioplasty and its clinical outcome

The use of computerized three dimensional imaging and automated milling of models to produce accurate titanium plates for the reconstruction of craniofacial defects is described. A total of 148 patients have had extensive calvarial defects repaired using this (computer aided design and manufacture) technique developed in our unit. Of these, 141 were repaired secondarily (delayed cranioplasty), whilst seven were repaired immediately following craniectomy (single stage cranioplasty). All cases were assessed for accuracy of fit, restoration of natural skull contour and aesthetics. Seventy-two patients were reviewed after 1 year to determine the effect on adverse preoperative symptoms. Of the plates 97% had an excellent or good intraoperative fit. The modal insertion time was only 15 minutes. Postoperatively 98% resulted in the restoration of natural skull shape and symmetry. After 1 year, 82% of patients had complete resolution or diminution in severity of the adverse symptoms. A staphylococcus infection necessitated the temporary removal of one plate.     

Use of hinge craniotomy for cerebral decompression. Technical note

Decompressive craniectomy to relieve cerebral edema and intracranial hypertension due to traumatic brain injury is a generally accepted practice; however, the procedure remains controversial because of its uncertain effects on outcome, specific complications such as the syndrome of the sinking skin flap, and the need for subsequent cranioplasty. The authors developed a novel craniotomy technique using titanium bone plates in a hinged fashion, which maintains cerebral protection while reducing postoperative complications and eliminating subsequent cranioplasty procedures. The authors conducted a retrospective review of data obtained in all consecutive patients who had undergone posttraumatic cerebral decompression craniotomy using the hinge technique at a Level I trauma facility between 1990 and 2004. Twenty-five patients, most of whom were male (88%) and Caucasian (88%) with a mean age of 38.2 +/- 16.1 years, underwent the hinge craniotomy. The in-hospital mortality rate was 48%, and good cerebral decompression was achieved. None of the patients required surgery for flap replacement. Long-term follow-up data showed that one patient required subsequent cranioplasty due to infection and one patient presented with cranial deformities. None of the patients presented with bone resorption or sinking flap syndrome. The hinge technique effectively prevents procedure-related morbidity and the need for subsequent surgical bone replacement otherwise introduced by traditional decompressive craniectomy. A randomized controlled trial is required to substantiate these findings.     

Overdrainage after ventriculoperitoneal shunting in a patient with a wide depressed skull bone defect: The effect of atmospheric pressure gradient

IntroductionIn patients with traumatic brain injury, an effective approach for managing refractory intracranial hypertension is wide decompressive craniectomy. Postoperative hydrocephalus is a frequent complication requiring cerebrospinal fluid (CSF) diversion.Presentation of caseA 50-year-old male who underwent decompressive craniectomy after traumatic brain injury. He developed hydrocephalus postoperatively, and accordingly we placed a ventriculoperitoneal shunt. However, an imbalance between the intra- and extra-cranial atmospheric pressures led to overdrainage, and he suffered cognitive disorders and extremity weakness. He remained supine for 5 days to avoid the effect of gravity on CSF diversion. After 20 days, we performed a cranioplasty using a titanium plate. The postoperative course was uneventful, and the patient achieved satisfactory recovery.DisccusionThe gravitational effect and the atmospheric pressure gradient effect are two factors associated in the ventriculoperitoneal (VP) shunt treatment of hydrocephalus for the patient who had decompressive craniectomy. These effects can be eliminated by supine bed rest and cranioplasty.ConclusionWe herein emphasize the efficacy of VP shunt, supine bed rest and cranioplasty in treating hydrocephalus patients who have undergone craniectomy. A flexible application of these procedures to change the gravitational effect and the atmospheric pressure gradient effect should promote a favorable outcome.     

Cranial repair: how complicated is filling a "hole"?

In general, cranioplasty is viewed as a straightforward surgical procedure, and for many years the complications associated with the procedure have been underestimated. We reviewed our 5-year experience consisting of 218 cranioplasties. Study outcomes focused specifically on the occurrence of complications after cranioplasty. Autologous bone-assisted and prosthetic cranioplasties were considered. Variables described by other authors to be associated with complications were studied, including history of previous cranioplasty, wider craniectomy size, bifrontal craniectomy, and delayed cranioplasty. We also analyzed the influence of material used for craniectomy on the occurrence of complications. The overall complication rate was 19.7%. Nineteen cases of infection (8.7%), 5 cases of postoperative wound dehiscence (2.3%), 6 cases of epidural hemorrhage (2.8%), and 13 cases of cranioplasty dislocation (5.9%) were observed. Bifrontal cranioplasties were more frequently associated with complications (p=0.01; Fisher's exact test) and infection (p<0.0001; Fisher's exact test). Postoperative wound dehiscence was more frequently observed with hand-made or custom-made cranioplasties compared with autologous cranioplasties (p=0.02). Early cranioplasty (<3 months from craniectomy) was significantly associated with cranioplasty dislocation (p=0.03). Logistical regression analysis showed that the only factor independently associated with complication was the site of cranioplasty (p=0.01). In particular, patients with a bifrontal cranioplasty had a 2-fold increased risk of complication (CI 95 1.1-3.6, p=0.017) and a 2.5-fold increased risk of developing infection (CI 95 1.3-4.9, p=0.009) compared with hemispheric/bihemispheric cranioplasty. Our analysis confirms that cranioplasty is burdened by a significant complication rate. In this context, bifrontal cranioplasty is related to a higher risk of complication and, in particular, infection.     

Stereolithography for Posterior Fossa Cranioplasty

Posterior fossa cranioplasty has been suggested for improvement of neurological symptoms following craniectomy. However, there is no particular recommendation in the literature about techniques for prosthesis manufacture and implantation. We report our experience using rapid prototyping technology and stereolithography for pre-surgical implant design and production of cranioplasties.     

Stereolithography for posterior fossa cranioplasty

Posterior fossa cranioplasty has been suggested for improvement of neurological symptoms following craniectomy. However, there is no particular recommendation in the literature about techniques for prosthesis manufacture and implantation. We report our experience using rapid prototyping technology and stereolithography for pre-surgical implant design and production of cranioplasties.     

Fracture précoce d’une cranioplastie en céramique macroporeuse d’hydroxyapatite

Different prosthesis implants are offered to perform a cranioplasty after a decompressive craniectomy when autologous bone graft cannot be used. The authors report the case of a 25-year-old man who benefited a unilateral decompressive craniectomy after a severe head trauma. Seven months later, a cranioplasty using custom macroporous hydroxyapatite prosthesis was performed. The postoperative course was marked by a generalized seizure leading to a traumatic head injury. The CT-scan showed a comminutive fracture of the prosthesis and an extradural hematoma. The patient underwent a removal of the fractured prosthesis and an evacuation of the extradural clot. The postoperative course was uneventful with a Glasgow outcome scale score at 5. A second cranioplasty using a polyether ether ketone (PEEK) implant was performed. Among cranioplasty prosthesis solutions, hydroxyapatite implants seem to have similar property to the bone. However, its weak mechanic resistance is an actual problem in patients susceptible to present generalized seizures with consecutive head impact. Hence, in patients with decompressive craniectomy who are exposed to potential brain injury, we favor the use of more resistant implant as PEEK prosthesis.     

A simple and accurate technique for cranioplasty in skull tumor surgery

Cranioplasty using methylmethacrylate is a common method in patients with cranial defects. However, it is often difficult to precisely restore a removed cranium. The authors developed a new technique of cranioplasty. In the present study, we first made a cast composed of methylmethacrylate using a bone flap. We then covered the cast with a sheet of wet gauze. The implant was made by applying methylmethacrylate cement onto the gauze. The implant is firmly fixed to the cranium with titanium plates. Five cranioplasties were perfomed using this new technique. All patients achieved excellent cosmetic results with no complications. This technique enables low-cost, easy and cosmetically successful cranioplastic surgery.     

Ethylene oxide gas sterilization: a simple technique for storing explanted skull bone. Technical note

The authors evaluated the effectiveness of a simple technique using ethylene oxide (EtO) gas sterilization and room temperature storage of autologous bone grafts for reconstructive cranioplasty following decompressive craniectomy. The authors retrospectively analyzed data in 103 consecutive patients who underwent cranioplasty following decompressive craniectomy for any cause at the University of Illinois at Chicago between 1999 and 2005. Patients with a pre-existing intracranial infection prior to craniectomy or lost to follow-up before reconstruction were excluded. Autologous bone grafts were cleansed of soft tissue, hermetically sealed in sterilization pouches for EtO gas sterilization, and stored at room temperature until reconstructive cranioplasty was performed. Cranioplasties were performed an average of 4 months after decompressive craniectomy, and the follow-up after reconstruction averaged 14 months. Excellent aesthetic and functional results after single-stage reconstruction were achieved in 95 patients (92.2%) as confirmed on computed tomography. An infection of the bone flap occurred in eight patients (7.8%), and the skull defects were eventually reconstructed using polymethylmethacrylate with satisfactory results. The mean preservation interval was 3.8 months in patients with uninfected flaps and 6.4 months in those with infected flaps (p = 0.02). A preservation time beyond 10 months was associated with a significantly increased risk of flap infection postcranioplasty (odds ratio [OR] 10.8, p = 0.02). Additionally, patients who had undergone multiple craniotomies demonstrated a trend toward increased infection rates (OR 3.0, p = 0.13). Data in this analysis support the effectiveness of this method, which can be performed at any institution that provides EtO gas sterilization services. The findings also suggest that bone flaps preserved beyond 10 months using this technique should be discarded or resterilized prior to reconstruction.     

Influence of cranioplasty on postural blood flow regulation, cerebrovascular reserve capacity, and cerebral glucose metabolism

OBJECT: The indications for cranioplasty after decompressive craniectomy are cosmetic repair and, mainly, restoration of cerebral protection. Although neurological improvement after cranioplasty is repeatedly noted, the reasons for this remain unclear. Few observations concerning the impact of cerebrospinal fluid hydrodynamic and/or atmospheric pressure have been published during the last decades. Relevant data concerning the cerebrovascular reserve (CVR) capacity and cerebral glucose metabolism before and after cranioplasty have been lacking until now. To gain further insight, this study was undertaken to investigate the impact of cranioplasty on indices of cerebral blood flow regulation and metabolism. METHODS: Thirteen patients in whom extensive craniectomies had been performed underwent a meticulous study of blood flow velocities in the middle cerebral artery (MCA) and extracranial internal carotid artery (ICA), as assessed by transcranial Doppler ultrasonography during postural maneuvers (supine and sitting positions) and during stimulation with 1 g of acetazolamide for the interpretation of CVR capacity. Twelve patients underwent 18-fluorodeoxyglucose positron emission tomography. These measurements were obtained before and 7 days after cranioplasty. Cranioplasty improved preoperative differences in MCA blood flow velocities when comparing those in the injured with those in the uninjured hemisphere. Similarly, cranioplasty resolved decreases in extracranial ICA blood flow in the injured hemisphere that were induced by postural changes, which was a constant finding prior to this procedure. More strikingly, however, the CVR capacity, which was severely impaired in both hemispheres, increased significantly after the procedure. Metabolic deficits, which were observed in the injured hemisphere, were found to improve after reimplantation of the skull bone flap. CONCLUSIONS: Cranioplasty appears to affect postural blood flow regulation, CVR capacity, and cerebral glucose metabolism markedly. Thus, early cranioplasty is warranted to facilitate rehabilitation in patients after decompressive craniectomy.     

计算机辅助设计个体化塑形钛网修补颅骨缺损

目的探讨计算机辅助设计个体化塑形钛网在颅骨修补术中的临床价值。方法126例颅骨缺损患者,采用随机双肓法分成两组：计算机塑形组66例,每例患者术前利用CT扫捕获取整个颅骨及缺损部位的三维数据,利用计算机辅助设计软件重建颅骨三维模型,根据模型计算缺损面积,设计剪切出塑形钛网、消毒备用,术中将塑形钛网根据解剖结构使用钛钉固定于缺损部位：传统手丁组60例,采用术中手工塑形的方法修补颅骨缺损。分析两组住院天数、手术时间、钛钉使用量、病人对成形术后头部外形的满意度指标。结果计算机塑形组平均住院天数16．28±2．12d,平均手术操作时间110．06±20．38min,钛钉使用量6．6±0．7枚,对塑形后外观满意9．2±0．9分。传统手工组平均住院天数17．56±4．57d,平均手术操作时间153．47±40．88min,钛钉使用量12．78±3．69枚,对塑形后外观满意度5．8±1．6分。结论个体化计算机三维塑型钛网修补颅骨缺损能够缩短手术时间,减少钛钉使用量和术后并发症．提高颅骨成形满意度。具有良好的推广应用价值。     

Cranioplasty with customized titanium and PEEK implants in a mechanical stress model

Large skull defects as a result of craniectomies due to cerebral insults, trauma, or tumors create functional and aesthetic disturbances for the patient. Cranioplasty with implants in these cases are an alternative to autogenous bone transplantation. In our clinic, customized titanium or optima poly-ether-ether ketone (PEEK) implants are used to reconstruct craniectomy defects. To compare the two materials we investigated the structural changes of the implants fixed to a sintered polyamide skull model under mechanical stress in four simplified models. In a standard testing machine, the models were subjected to a load under a quasi-static loading rate of 1.925?mm/min. Fractures of the PEEK implants occurred at a force of 24.2 and 24.5?kN with a displacement of 8.4 and 8?mm. The titanium implants showed no deformation, but extensive damage was seen in the polyamide skull models. The highest pressures achieved were 45.8 and 50.9?kN. In a simplified model with quasi-static loading, both implants withstood forces that were higher than those capable of causing skull fractures. It seems that the mechanical properties of PEEK could provide better protection when used for cranioplasty in patients after craniectomy if reconstruction with autogenous bone is not possible.     

New reconstructive technologies after decompressive craniectomy in traumatic brain injury: the role of three-dimensional titanium mesh

Functional and aesthetic reconstruction after wide decompressive craniectomy directly correlates with subsequent quality of life. Advancements in the development of biomaterials have now made three-dimensional (3-D) titanium mesh a new option for the repair of skull defects after craniectomy. The purpose of this study was to review aesthetic and surgical outcomes and complications of patients who had skull defects repaired with 3-D titanium mesh. The records of 40 adult patients (31 unilateral craniectomies and 9 bilateral craniectomies) who underwent a computer-assisted designed titanium mesh implant at a university hospital from January 2008 to January 2010 were retrospectively reviewed. Aesthetic outcomes, cranial nerve V and VII function, and complications (hardware extrusions, meningitis, osteomyelitis, brain abscess, and pneumocephalus) were evaluated. The craniofacial symmetry, implant stability, and functional outcomes were excellent for all patients. No patients had trigeminal or facial dysfunction. All had excellent cosmetic results as measured by post-reduction radiographs and personal and family perceptions of the forehead contour. Two patients had delayed wound healing and subsequent subclinical wound infections, which resolved after treatment with antibiotics for 2 weeks. Craniofacial skeletal reconstruction with 3-D titanium mesh results in excellent forehead contour and cosmesis, and subsequently a better quality of life with few complications. Titanium mesh reconstruction offers a favorable alternative to other graft materials in the repair of large skull defects.     

Osteoregenerative lateral suboccipital craniectomy using fibrin glue

Summary This report describes a simple technique of cranioplasty for suboccipital craniectomy and the results of a clinical study to assess the effects of fibrin glue on regeneration of the skull. Cranioplasty using a mixture of autologous bone chips and human allogenic fibrin glue was performed in 31 patients who received lateral suboccipital craniectomy. Long-term observations with three-dimensional CT showed satisfactory reconstruction of the mastoid-occipital bone plate in 25 patients (81%); among them, a nearly complete reconstruction of the occipital bone (plate) was found in 14 patients. Regeneration of the bone began 6 months after surgery on the inner surface, adjacent to the dura mater. In conclusion, the present technique provides a new simple method to restore an autologous bone plate in a cranial defect made by piecemeal craniectomy.     

A new technique for cranioplasty with L-shaped titanium plates and combination ceramic implants composed of hydroxyapatite and tricalcium phosphate (Ceratite)

OBJECTIVE: The use of hydroxyapatite-based ceramics for cranioplasties has recently increased in Japan, because of the good cosmetic outcomes, biocompatibility, strength, osteoconductive properties, and lack of risk of disease transmission associated with these materials. However, miniplate fixation has not been possible for ceramic implants. We describe a new technique for miniplate fixation of ceramic implants. METHODS: Combination ceramic implants composed of hydroxyapatite and tricalcium phosphate (Ceratite; NGK Spark Plug Co., Aichi, Japan) were used for cranioplasties. A slot and a pair of holes were cut in each Ceratite implant, for use as a fixation unit. We have also developed a new L-shaped titanium plate (HOMS Engineering Inc., Nagano, Japan) that fits into the fixation unit. We first insert an L-shaped titanium plate through the slot from the back surface of the Ceratite implant. We then bend the plate outward at the front surface of the Ceratite implant and fix it to the cranium of the patient with titanium screws. The Ceratite implant is usually firmly fixed to the cranium of the patient with three L-shaped titanium plates. RESULTS: Using L-shaped titanium plates and Ceratite implants, we successfully performed cranioplasties for seven patients with cranial defects resulting from external decompression craniotomies. The Ceratite implant exactly fit the bone window for each patient. Surgical maneuvers were simple and easy for all patients, permitting shorter operating times. All Ceratite implants were firmly fixed, and no postoperative infections have occurred. CONCLUSION: Our new technique for cranioplasty is simple and allows rigid fixation of Ceratite implants.     

Analysis of the factors affecting graft infection after cranioplasty

Background

The predictors of graft infection after cranioplasty (GIC) following decompressive craniectomy are not well established. Knowledge of the risk factors for GIC will allow development of preventive measures designed to reduce infection rates. Therefore, the objective of this study was to identify risk factors for the development of GIC.

Methods

A total of 85 patients underwent reconstructive cranioplasty after decompressive craniectomy between January 2009 and July 2011 and had a follow-up period of > 1 year; charts were reviewed retrospectively. Although autograft was used whenever possible, artificial bone was used for cranioplasty. GIC was defined as infection requiring removal of the bone graft.

Results

GIC occurred in six patients (7.05 %). GIC was not related to the indications for craniectomy, the interval of cranioplasty, graft material, or the size of the bone defect (p?=?0.433, p?=?0.206, p?=?0.665, and p?=?0.999, respectively). The GIC rate was significantly related to previous temporalis muscle resection, preoperative subgaleal fluid collection, operative times > 120 min, and postoperative wound disruptions (p?=?0.001, p?<?0.001, p?=?0.035, and p?=?0.016, respectively). Multiple logistic regression showed that the presence of a subgaleal fluid collection before cranioplasty significantly increased the risk of GIC (OR: 38.53; 95 % CI: 2.77–535.6; p?=?0.006).

Conclusions

The results of this study suggest that long operative times (> 120 min), craniectomy with temporalis muscle resection, the presence of preoperative subgaleal fluid collection, and postoperative wound disruption may be risk factors for graft infection after cranioplasty. Surgical techniques should be developed to reduce operative time and to avoid temporalis muscle resection when possible. In addition, meticulous dural closure aimed at reducing the formation of subgaleal fluid collection is important for the prevention of graft infections after cranioplasty.     

Simple and safe method of cranial reconstruction after posterior fossa craniectomy

BACKGROUND: Reconstructing the posterior fossa after surgical intervention in this region is important both for prevention of postoperative complication such as headache and for cosmetic purposes. Several methods have been reported that use either synthetic or natural graft, the latter being either autograft or allograft. The previously described methods require either surgical intervention on a second setting or an additional procedure that prolongs the time of the surgery and may contribute to morbidity. The present report describes a simple modified method of reconstructing the postcraniectomy defect by using the patients' own bone dust, tissue glue, and gel foam sheets. METHODS: The method of reconstruction requires collection of as much as possible of the produced bone dust at the time of craniectomy, adding tissue glue, placing in between 2 sheets of gel foam, and shaping it to match the surgical defect. RESULTS: Ten cases of various posterior fossa pathologies managed at King Faisal hospital of the university between January 2000 and September 2004 had reconstruction of the posterior fossa after craniectomy during the same operative setting using the described method of cranial reconstruction. No complication was noted. Patients did not have any delayed postcraniectomy pain at reconstruction site. Postoperative plane x-ray of the skull and computed tomography showed good healing and shaping of the suboccipital bone at the surgical defect. CONCLUSIONS: Reconstructive cranioplasty is an important part of any posterior fossa exposure. The present report describes a safe and simple method that gives acceptable results both clinically and radiologically.     

A case of the traumatic hydrocephalus after large craniectomy for acute subdural hematoma

Decompressive craniectomy sometimes causes neurological deficits known as 'the syndrome of the sinking skin flap' or 'the symptom of the trephined'. These disorders can be corrected with cranioplasty, but there is no consensus on appropriate treatments. We report a case of successful correction of traumatic hydrocephalus following craniotomy. A 50-year-old man was admitted to our hospital with disturbance of consciousness after a head injury. Decompressive craniectomy was performed for a right acute subdural hematoma. His consciousness recovered after the operation, but then deteriorated gradually and left hemiparesis occurred. CT scan revealed midline shift from right to left. These symptoms and CT findings were not improved after cranioplasty, but were improved with removal of the CSF from the adhered subarachnoid space. The diagnosis was traumatic hydrocephalus, and a cisternoperitoneal shunt was subsequently placed. We report this case to emphasize the necessity for study of CSF circulation, as well as the importance of examination of CBF and ICP after craniectomy.     

早期颅骨缺损修补术的效果及安全性研究

目的评价早期颅骨修补术的安全性和有效性。方法因颅脑外伤导致难治性颅高压于2006年1月～2011年6月在我科行去大骨瓣减压术90例,其中早期行颅骨修补术60例(早期修补组),行颅骨修补术的时间间隔去大骨瓣减压术38.2(36～40)d;另30例在大骨瓣减压术后3个月行颅骨修补术(对照组),行颅骨修补术的时间间隔去大骨瓣减压术107.6(90～153)d。通过分析手术耗时、皮瓣游离时间、手术失血量及并发症来回顾性研究两组的临床效果,评估早期颅骨修补的有效性。结果早期修补组的手术总时间比对照组明显缩短,为(95.33±4.71)min vs.(133.67±5.12)min,皮瓣游离时间明显缩短,为(15.3±1.24)min vs.(40.67±3.11)min,手术总出血量明显减少,为(336.67±24.6)mlvs.(573.30±26.7)ml(P<0.01)。两组术后伤口感染率无明显差别,但早期修补组的硬膜下积液率及皮瓣游离过程中硬膜破裂率明显少于对照组,分别为6.7%(4/60)vs.30%(9/30)和3.3%(2/60)vs.26.7%(8/30)(P<0.01)。结论早期颅骨修补手术,能够在手术操作过程中更好地进行软组织分离,减少出血,同时也不会增加手术带来的包括感染、硬膜下积液及硬膜破裂甚至脑实质损伤等并发症。     

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.

Graphical abstract