Cranioplasty with individual carbon fibre reinforced polymere (CFRP) medical grade implants based on CAD/CAM technique

Summary.  Background: The authors present a new method for the reconstruction of large or complex-formed cranial bone defects using prefabricated, computer-generated, individual CFRP (carbon fibre reinforced plastics) medical grade implants.  Method: CFRP is a composite material containing carbon fibres embedded in an epoxy resin matrix. It is radiolucent, heat-resistant, extremely strong and light (its weight is 20% that of steel), has a modulus of elasticity close to that of bone, and an established biocompatibility. The utilisation of a CAD/CAM (computer aided design/computer aided manufacture) technique based on digitised computed tomography (CT) data, with stereolithographic modelling as intermediate step, enabled the production of individual, prefabricated CFRP medical grade implants with an arithmetical maximum aberration in extension of less than ±0.25 mm.  Between 1995 and February 2002, 29 patients (15 men and 14 women; mean age, 39.9 years; range, 16 to 67 years) underwent cranioplasty with CFRP medical grade implants at the neurosurgical department of the University of Vienna. Twenty-four patients were repaired secondarily (delayed cranioplasty) while 5 were repaired immediately following craniectomy (single stage cranioplasty). All cases were assessed for the accuracy of the intra-operative fit of the implant, restoration of the natural skull contour and aesthetics and adverse symptoms.  Findings: The intra-operative fit was excellent in 93.1% and good in 6.9% of the implants. In two cases minor adjustments of the bony margin of the defect were required. The operating time for insertion ranged from 16 to 38 minutes, median 21 minutes. Postoperatively, 86.2% of the patients graded the restoration of their natural skull shape and symmetry as excellent while 13.8% termed it good. In one patient a non-space occupying subdural hygroma was found at the follow-up, but required no intervention. Two patients experienced atrophy of the frontal portion of the temporal muscle while one patient had a transient palsy of the frontal branch of the facial nerve. Over the mean follow-up period of 3.3 years (range, 0.08 to 6.8 years), there were no adverse reactions and no plate had to be removed.  Interpretation: Individual, prefabricated CFRP medical grade implants may be considered as an alternative to conventionally utilised materials for cranioplasty, in particular in the challenging group of patients with extensive cranial defects or more complex-formed defects of the fronto-orbital or temporo-zygomatic region, guaranteeing short operating times and excellent functional and aesthetic results, which justifies the expense of their production. Published online October 31, 2002 Correspondence: Dr. Walter Saringer, Neurochirurgische Universit?tsklinik, Universit?t Wien, W?hringer Gürtel 18-20, A-1090 Wien, Austria.     

Growing skull fractures: A clinical study of 41 patients

Summary Growing skull fractures are rare complications of head injury, occurring almost exclusively in infants and children under the age of three. A retrospective review at our Institute yielded 41 patients with this entity over a period of 20 years (1975–1995). The age at presentation ranged from less than 1 year to 62 years, with 33 (80.5%) patients being less than 5 years of age. The cause of injury was either a fall from a height (93%) or a road traffic accident. The most common location of a growing skull fracture was either parietal or frontoparietal (56%). One patient had a posterior fossa growing skull fracture. CT scan was performed in 19 patients which demonstrated an underlying porencephalic cyst, hydrocephalus or a cyst communicating with the ventricle.In 5 children, a ventriculo-peritoneal shunt alone was performed. Twenty four patients underwent a duro- and cranioplasty while a duroplasty alone was performed in 8 patients. The material used for cranioplasty included acrylic, wire mesh, steel plates or autologous bone. Three patients died, one due to an anaesthetic complication and two as a result of postoperative meningitis. Post-operative CSF leaks occurred in 3 patients, which were managed by a lumbar drain. Six patients had local wound infection.     

Effects of cranioplasty on neurological function and cerebral blood flow

The authors present a review of their experience of cranioplasty in cases showing of skull defects. Forty recent case reports were retained out of a total of 125 cases and of these, 15 showed neurological deficiency prior to cranioplasty. In 7 out of these 15 cases cranioplasty appeared to have no effect, but in the 8 remaining cases, an improvement in the neurological condition was observed. In connection with these clinical observations, a recent study of a small group of patients with skull defects used the Xenon 133 inhalation method to investigate cerebral blood flow. In all cases these was a significant postoperative improvement in cerebral blood flow. The rate varying from 15 to 30% and this improvement was even observable in the case of small skull defects of the order of 10 cm2. The mechanism giving rise to such improvements is discussed; it may be related to cerebral hemodynamic normalization after skull restoration. The improvement in cerebral blood flow brought about by cranioplasty in all the cases studied suggests that this technique may be important not only for simple skull repair but also to improve neurological function.     

Prospective study on cranioplasty with individual carbon fiber reinforced polymer (CFRP) implants produced by means of stereolithography

BACKGROUND: The aim of this study was to evaluate the value of carbon fiber reinforced polymer (CFRP) cranial implants produced by means of 3-dimensional (3D) stereolithography (SL) and template modeling for reconstructions of complex or extensive cranial defects. PATIENTS: A series of 41 cranioplasties with individual CFRP implants was performed in 37 patients between April 1996 and November 2002. Only patients with complex and/or large cranial defects were included, most of them having extended scarring or dural calcification and poor quality of the overlying soft-tissue cover after infection or multiple preceding operations. Involvement of frontal sinus, a known risk factor for complications after cranioplasty, was the case in 21 patients (51.2%). METHODS: A computer-based 3D model of the skull with the bony defect was generated by means of stereolithography after acquisition, evaluation and transfer of the patient's helical computed tomography (CT) data. A wax template of the defect that was used to design the individual prosthesis-shape was invested in dental stone. Then, the cranial implant was fabricated out of CFRP by loosen mold. RESULTS: Reconstruction of defects measuring up to 17 x 9 cm was performed. The intra-operative fit of the implants was excellent in 36 (87.8%), good in 1 (2.4%), and fair in 4 (9.8%) of the cases. Problems of implant fit occurred because of extended scarring and poor quality of soft-tissue cover. Adverse reactions were observed in 5 patients (1 subdural, 1 subcutaneous hematoma, 2 infections, 1 allergic reaction). Excellent contours and a solid stable reconstruction have been maintained in 30 out of 35 remaining plates (mean follow-up 3.6 years). No adverse effects concerning postoperative imaging, the accuracy of electroencephalograms and radiation therapy have been observed. CONCLUSIONS: The authors believe that this relatively new technique represents an advance in the management of complex and large cranial defects, but seems less suitable for simple defects because of cost-intensive techniques. Because of the high mechanical strength, biocompatibility, innovative design, and especially radiolucency, CFRP implants should, however, be considered in smaller defects if further imaging investigations or irradiation therapies are necessary.     

Cranioplasty: a review of 1030 cases of penetrating head injury.

A total of 491 cranioplasties performed in a population of 1030 cases of penetrating head injury are reviewed. The morbidity rate was 5.5%, and the mortality rate was 0.2%. The clinical criteria of improving cosmetic defects and restoring craniocerebral protection are established, based on the location and size of the skull defect. Cranioplasty after penetrating head injury should be deferred for a minimum of 1 year to control morbidity. Complication of the original injury and surgical debridement increase the morbidity rate of cranioplasty. Post-traumatic epilepsy is not related to skull defects per se; neither is it affected by cranioplasty. Acrylic is an acceptable cranioplasty material if there is strict adherence to good surgical technique.     

Cranioplasty following decompressive craniectomy--analysis of 300 cases (author's transl)

Three hundred cases of cranioplasty, following large decompressive craniectomy for various diseases, were analyzed. 1. Neurological status was evaluated before and after cranioplasty in 52 patients with remaining neurological deficit. There observed no changes in 13 patients with skin flap of full or bulging type. However, 4 (10%) among 39 patients with skin flap of sinking or flat type showed unquestionable objective improvement within a few days following cranioplasty, after stationary period of more than 2 and half months. In these situation, placement of acrylic plate has presumably corrected deformity of underlying brain tissue secondary to pressure gradient between extra- and intracranial spaces, which might have unidentifiably caused unfavorable eflects on neural function. 2. Seven children underwent procedure within 24 months of age and all of them had troublesome bluging of skin flap. This deformity was extreme in 5, in whom the dura mater was not repaired in the previous surgery. Those children had various intracranial problems as causes of bulging skin flap-hydrocephaly in 2, porencephaly in 1, CSF collection under the skin flap in 4, brain migration in 2, enlarged subarachnoid space over the bulging brain surface in 2, deformity of the skull resembling growing skull fracture in 5; and as complications of cranioplasty in 3 and infection in 2. 3. Fracture of the cranioplasty was seen in 7 (2%) among 300 cases and 6 of them were under the age of 7. In one case, there occurred 3 episodes of fracture. 4. Infected cranioplasty, in all as epidural empyema, was seen in 10 (3%) of 300 cases. One of the most important factors related to infection, was the time interval after the primary surgery; all infected cases were operated on within 3 months.     

Late infection after cranioplasty--review of 14 cases

The incidence of late infection after cranioplasty was studied in 130 patients with 133 cranioplasties. The materials used were prefabricated resin in 62 cases, autogenic bone in 38, intraoperatively fashioned resin in 25, and vitallium in eight. Six infections were documented, for an infection rate of 4.5%. In addition to these six cases, we studied eight patients with infections who had undergone cranioplasty elsewhere but had the infected plates removed in our hospitals. Among the 14 cases of infection, the intervals between cranioplasty and plate removal were 3 to 43 months (average, 10.5 months). The eight patients referred from other hospitals had a significantly shorter average interval between external decompression and cranioplasty than did patients who did not develop infection (2.6 versus 6.7 months; p less than 0.005). Systemic signs were mild despite obvious local signs of infection. Of the 11 first infections, nine (82%) were associated with discharge of pus from a fistula; in these cases a galeal suture had become infected apparently through scratching by the patients. In contrast, in the three patients who had had a previous infection, the second infection manifested as subgaleal and epidural empyema or meningitis without a fistula or pus discharge. Nine infections (69%) were due to Staphylococcus. All but two patients required removal of the infected plates. One recovered with conservative therapy and one died of meningitis, giving a mortality rate of 0.8%. No matter how mild the systemic signs, late infection warrants surgical debridement and plate removal. The risk factors for late infection of cranioplasty are discussed.     

颅骨嗜酸性肉芽肿切除15例报告

目的探讨颅骨嗜酸性肉芽肿（skull eosinophilic granuloma,SEG）手术治疗的效果。方法2011年1月～2012年9月对15例SEG,术中根据病变浸润、破坏颅骨骨质程度和病灶范围大小,分别采用病灶刮除和切除术,对于颅骨缺损直径〉3cm者,行一期颅骨修补。结果10例单纯手术切除,5例病灶刮除;7例行钛网修补。术后未辅助放、化疗。手术时间95～160min,（127．8±32．5）min;术中出血93～118ml,（105±13）ml。术后住院8～10d。术后病理：黄色肉芽肿,属于嗜酸性肉芽肿黄色肿块期。术后门诊随访1年,头颅CT、MRI检查均未见复发病灶。结论SEG经单纯病灶清除术后患者恢复良好,复发率低。单发、局限性病灶,无明显全身症状者,可不辅助放、化疗。     

Effect of cranioplasty on cerebrospinal fluid hydrodynamics in patients with the syndrome of the trephined

Summary Forty patients with cranial bone defects after craniectomy underwent extensive cerebrospinal fluid (CSF) hydrodynamic investigations by means of a CSF infusion test before and after cranioplasty. The results of these investigations were related to the clinical signs of the patients before and after cranioplasty and to the size and location of the skull bone defect. Twenty-two patients were considered to have the syndrome of the trephined (ST). The remaining patients were either free of symptoms or had symptoms not related to ST.CSF hydrodynamic variables that were changed before and normalized after cranioplasty include the following: Resting pressure, sagittal sinus pressure, buffer volume, elastance at resting pressure and pulse variations at resting pressure. The changes were statistically significant mainly in ST patients who were also relieved of their symptoms after cranioplasty.This investigation was approved by the Ethical committee, Umeå University Hospital and supported by grants from the Swedish Medical Research Council (Project No. 04X-04125) and from the Amanda Vilhelmina and Per Algot Mångbergs Foundation for Medical Research, University of Umeå.     

A Novel Graft Material for Preventing Cerebrospinal Fluid Leakage in Skull Base Reconstruction: Technical Note of Perifascial Areolar Tissue

Objectives Perifascial areolar tissue (PAT), a layer of loose connective tissue on the deep fascias with a rich vascular plexus, serves as a vital cover over defects with scarce vascularity. We report the usefulness of PAT as a nonvascularized alternative to flaps for reconstruction of dural defects in skull base surgery and transsphenoidal surgery while evaluating its effect on control of cerebrospinal fluid (CSF) leakage. Design A retrospective chart analysis was performed on patients who had undergone repair of a dural defect with PAT during skull base surgery or transsphenoidal surgery between December 2004 and October 2011. Results Twenty-one patients were included: 11 patients had received surgical treatment and/or irradiation. Fourteen of the 21 patients had pre- and/or intraoperative CSF leakage. Only one patient (4.8%) had postoperative CSF leakage requiring additional surgical repair. Ten patients underwent postoperative irradiation from 1 to 15 months after transplant of the PAT. None of the patients had postoperative CSF leakage after irradiation. Conclusion We successfully repaired dural defects using PAT in skull base surgery and transsphenoidal surgery, even in patients with a history of multiple operations and radiotherapy. PAT may serve as a valuable tool for skull base reconstruction.     

自体颅骨粉一期修复颅骨缺损的临床应用

目的探讨用自体颅骨骨粉一期修复颅骨缺损的临床应用. 方法 1999年10月～2002年12月,采用自体颅骨骨粉加医用黏合剂原位黏合,对128例重型颅脑损伤、急性颅内血肿、颅骨肿瘤及脑肿瘤并颅骨侵犯开颅术后行一期再植成形术,术后随访3～24个月,通过CT或X线片观察骨质生长情况. 结果一次完成减压及成形术,时间较常规手术延长5～l0分钟,修复颅骨外观正常,无凹陷、突出,术后12个月再植骨与正常颅骨完全融合,类似正常颅骨形态.再植修复成功123例,占96.1%,5例因骨粉量少成形欠佳,但未见脑搏动和缺损综合征,均不需二期修补. 结论自体颅骨骨粉加医用黏合剂一期颅骨再植成形术,能够有效避免传统的二期颅骨缺损修补术和并发症.     

Post-traumatic intradiploic pseudomeningocele in children

Summary Eight children with post-traumatic pseudomeningocele are reported. In this paper the mean age at the time of injury was one year and ten months. All of them gave a history of a fall from a height. In six patients the meningocele was located in the parietooccipital region. The frontal bone was involved in one and the roof of the orbit in another. All these patients had localized progressive swelling of the skull associated with a bony defect. Four patients had a history of convulsion and three had hemiparesis. The meningocele was excised, the dural defect repaired and a cranioplasty was performed in all. Good recovery was observed in all of them.     

Halo pin intracranial penetration and epidural abscess in a patient with a previous cranioplasty: case report and review of the literature.

STUDY DESIGN: Report of a patient with an epidural abscess after halo pin intracranial penetration at the site of a previous cranioplasty. OBJECTIVES: To report a rare case of intracranial penetration at the site of a previous cranioplasty associated with epidural abscess, and to discuss the diagnostic and therapeutic approach to its management. SUMMARY OF BACKGROUND DATA: The most serious complications associated with use of halo device occur when pins penetrate the inner table of the skull, resulting in cerebrospinal fluid leak and rarely in an intracranial abscess. However, no mention of intracranial halo pin penetration at the site of a previous cranioplasty was found in the literature. METHODS: A 64-year-old man with ankylosing spondylitis had a halo vest placed for management of a fracture dislocation through the C5-C6 intervertebral disc space associated with left C6 radiculopathy. One week later, the patient experienced fever and headache associated with pain, redness, and drainage at the site of the insertion of the left posterior pin. Computed tomography of the brain showed a 1.5-cm intracranial penetration of the halo pin through a previous cranioplasty of the temporal bone, associated with epidural abscess and cerebral edema in the left temporoparietal lobe. The pins and the halo vest were removed, the pin site was cleaned, and a Philadelphia cervical collar was applied. Staphylococcus epidermidis grew on the culture of drainage from the pin site. The patient started immediate intravenous antibiotic treatment for 2 weeks, followed by oral antibiotics for 2 additional weeks. RESULTS: The patient had gradual improvement of his symptoms within the first 48 hours. At the latest follow-up visit, he had fully recovered and his fracture had healed. CONCLUSIONS: The halo device should not be used for patients with a previous cranioplasty, especially if the pins cannot be inserted at other safe areas of the skull. A thorough medical history and physical examination of the skull are important before the application of a halo device. Computed tomography of the skull may be necessary before elective halo application for patients with concomitant head trauma, confusion, or intoxication and for patients with a previous cranioplasty to ascertain the safest pin sites.     

Composite skull and dura defect reconstruction using combined latissimus dorsi musculocutaneous and serratus anterior muscle‐rib free flap coupled with vascularized galea transfer: A case report

Recalcitrant epidural abscess following cranioplasty is a complicated problem, which becomes even more trying when large span of dura and skull bone are being replaced by alloplastic materials. A 22‐year‐old male underwent right fronto‐temporo‐parietal craniectomy and duroplasty with artificial dura graft after traumatic brain injury. Epidural abscesses recurred after cranioplasty with autologous bone graft as well as with a methyl methacrylate bone plate. The massive defects of both the dura and skull bone (15 × 9 cm) caused by radical debridement were reconstructed successfully with a combined free latissimus dorsi and serratus anterior myo‐osseous flap transfer plus galea flap transposition. Proper contour and adequate stability of the construct were maintained during 2‐year follow up without episodes of relapsing infection. © 2010 Wiley‐Liss, Inc. Microsurgery, 2010.     

Clinical application of bone cement in cranioplasty

Cranioplasty usually performed in case of skull defect after craniocerebral injuries. Plexiglass or metal plate were used frequently in our country. This article introduces a new kind of material--bone cement--for skull restoration. 152 cases of skull defects were repaired by bone cement in our clinic. The advantages as below: (1) Bone cement is easy to mould and good in cosmetic result; (2) It's mechanical functions are reliable; (3) Less irritant to the surrounding tissues. The procedures of the operation and principles in utilizing this material were present in detail.     

Cranioplasty for midline metopic suture defects in adults with cleidocranial dysplasia.

OBJECTIVE: Patients with cleidocranial dysplasia often express concerns related to their perception of an undesirable esthetic appearance of their forehead and skull because of a combination of the persistence of metopic suture defects and frontal bossing. This case series reviews the use of a cranioplasty technique that has been developed to address such concerns. STUDY DESIGN: A series of 7 adult patients with cleidocranial dysplasia were treated using a cranioplasty technique to correct visible metopic suture defects in the forehead region. The patients were 4 males and 3 females with a mean age of 29.0 years. All 7 patients underwent identical cranioplasty procedures. RESULTS: The metopic suture cranial defects were found to range in size from 0.6 to 2.4 cm in diameter and were present as full-thickness osseous defects in 4 of the 7 patients. All postoperative complications resolved spontaneously. Inpatient admission times ranged from 1 to 3 days. Follow-up ranged from 9 to 48 months with satisfactory subjective esthetic outcomes. The patients were content in all cases. CONCLUSION: This cranioplasty procedure successfully addresses the specific esthetic concerns of a rare and unique group of individuals. The procedure can be offered to cleidocranial dysplasia patients as part of their overall comprehensive craniomaxillofacial management.     

塑型钛板颅骨修补20例临床应用

目的 探讨塑型钛板在颅骨修补术中的临床效果。方法 对我科在2009年4月~2010年10月收治各种原因引起的颅骨缺损20例,使用塑型钛板进行颅骨修补术的临床资料进行回顾性分析。结果 20例塑型颅骨修补术病人,手术时间除2例颅骨肿瘤为即时修补外,其余均为第一次手术后3～6个月;除1人术后出现继发癫痫外,其余均恢复良好。术后无伤口感染、皮下积液、继发出血、钛板外露等并发症,术后颅骨外观恢复满意。结论 采用塑型钛板行颅骨修补术,手术快捷方便、效果满意,具有广泛临床应用价值。     

D型连头婴头颅缺损一期重建相关问题探讨

目的 探讨D型连头婴分离手术后头皮，颅骨，硬膜缺损的一期修复重建方法。方法 头皮应用扩张器进行扩张，采用邻近头皮皮瓣转移修复头皮缺损，用带蒂骨膜修补硬膜缺损，用钛板修补颅骨缺损等进行一期重建。结果 存活的婴儿术后颅骨塑形及头皮愈合良好。结论 D型连头婴可以进行头颅缺损一期重建。     

Intraoperative template-molded bone flap reconstruction for patient-specific cranioplasty

Cranioplasty is a common neurosurgical procedure. Free-hand molding of polymethyl methacrylate (PMMA) cement into complex three-dimensional shapes is often time-consuming and may result in disappointing cosmetic outcomes. Computer-assisted patient-specific implants address these disadvantages but are associated with long production times and high costs. In this study, we evaluated the clinical, radiological, and cosmetic outcomes of a time-saving and inexpensive intraoperative method to mold custom-made implants for immediate single-stage or delayed cranioplasty. Data were collected from patients in whom cranioplasty became necessary after removal of bone flaps affected by intracranial infection, tumor invasion, or trauma. A PMMA replica was cast between a negative form of the patient's own bone flap and the original bone flap with exactly the same shape, thickness, and dimensions. Clinical and radiological follow-up was performed 2?months post-surgery. Patient satisfaction (Odom criteria) and cosmesis (visual analogue scale for cosmesis) were evaluated 1 to 3?years after cranioplasty. Twenty-seven patients underwent intraoperative template-molded patient-specific cranioplasty with PMMA. The indications for cranioplasty included bone flap infection (56%, n?=?15), calvarian tumor resection (37%, n?=?10), and defect after trauma (7%, n?=?2). The mean duration of the molding procedure was 19?±?7?min. Excellent radiological implant alignment was achieved in 94% of the cases. All (n?=?23) but one patient rated the cosmetic outcome (mean 1.4?years after cranioplasty) as excellent (70%, n?=?16) or good (26%, n?=?6). Intraoperative cast-molded reconstructive cranioplasty is a feasible, accurate, fast, and cost-efficient technique that results in excellent cosmetic outcomes, even with large and complex skull defects.     

Long-term cognitive, emotional, and functional outcomes in trauma intensive care unit survivors without intracranial hemorrhage

BACKGROUND: Trauma patients without intracranial hemorrhage or focal neurologic deficits are typically considered low risk for lasting neuropsychological and emotional deficits, and such sequela may be overlooked, especially in those with skull fractures and concussions. We undertook this study to determine the prevalence of and risk factors for persistent cognitive impairment and emotional and functional difficulties in a sample of adult trauma intensive care unit survivors without intracranial hemorrhage. METHODS: We queried the Vanderbilt University Trauma Registry for all patients admitted during 2003 with an Injury Severity Score >25 and a head computed tomography scan showing no intracranial hemorrhage. Of the 97 patients identified, 58 were evaluated, in person between 12 to 24 months after hospital discharge, with a comprehensive battery of cognitive, emotional, and functional instruments. The Informant Questionnaire of Cognitive Decline in the Elderly-Short Form (IQCODE-SF) was used to evaluate for pre-existing cognitive deficits in patients suspected of having cognitive impairment before their trauma. RESULTS: A total of 33 (57%) patients were determined to have cognitive impairment, which was most pronounced in the domains of attention and executive functioning/verbal fluency. Of these patients, one (3%) was determined by the IQCODE-SF to be cognitively impaired before trauma intensive care unit hospitalization. Of the 58 patients studied, 21 (36.2%) had a concussion or skull fracture and 37 (63.8%) had neither. Cognitive impairment was significantly more likely to occur in patients who sustained a concussion or skull fracture than in trauma patients who did not (81% versus 43%; p = 0.006). Patients reported significant depressive symptoms (56%), significant symptoms of posttraumatic stress disorder (38%), and significant symptoms of anxiety (29%). Quality of life scores were lower than in the general United States population and employment difficulties were widespread. A total of 34% of patients reported being unemployed at follow-up, and cognitive impairment was more common among these patients compared with patients in the workforce (p = 0.03). Neither cognitive impairment nor emotional dysfunction was associated with age, sex, race, Injury Severity Score, blood loss, ventilatory days, or intramedullary nailing of long-bone fractures. CONCLUSIONS: The majority of trauma survivors without intracranial hemorrhage display persistent cognitive impairment, which is nearly twice as likely in those with skull fractures or concussions. This cognitive impairment was associated with functional defects, poor quality of life, and an inability to return to work. Future research must delineate modifiable risk factors for these poor outcomes, especially in patients with skull fractures and concussions, to help improve long-term cognitive and functional status.