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.     

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.     

Long-term complications of decompressive craniectomy for head injury

There is currently much interest in the use of decompressive craniectomy for intracranial hypertension. Though technically straightforward, the procedure is not without significant complications. A retrospective analysis was undertaken of 164 patients who had had a decompressive craniectomy for severe head injury in the years 2004 to 2009 at the two major hospitals in Western Australia. Eighty-six patients had a bifrontal decompression and seventy-eight had a unilateral decompression. Two patients died due to post-operative care issues. Complications attributable to the decompressive surgery were: herniation of the cortex through the bone defect (42 patients, 25.6%), subdural effusion (81 patients, 49.4%), seizures (36 patients, 22%), hydrocephalus (23 patients, 14%), and syndrome of the trephined (2 patients, 1.2%). Complications attributable to the subsequent cranioplasty included: sudden death due to massive cerebral swelling in 3 patients (2.2%), infection requiring removal of the bone flap in 16 patients (11.6%), and bone flap resorption requiring augmentation in 10 patients (7.2%). After excluding simple complications such as subdural effusion and brain herniation through the skull defect and some patients who died as a direct consequence of traumatic brain or extracranial injury, 81 patients (55.5%) had at least one complication after decompressive craniectomy. The occurrence of at least one complication after decompressive craniectomy was significantly associated with an increased risk of prolonged stay in the hospital or rehabilitation facility (odds ratio 2.54, 95%confidence interval 1.22,5.24, p=0.013), after adjusting for predicted risk of unfavorable outcome.     

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.     

Effect of microorganisms isolated by preoperative osseous sampling on surgical site infection after autologous cranioplasty: A single-center experience

PurposeThe most frequent postoperative complication in autologous cranioplasty (AC) is infection. European recommendations include osseous sampling before cryogenic storage of a bone flap. We evaluated the clinical impact of this sampling.MethodsAll patients who underwent decompressive craniectomy (DC) and AC in our center between November 2010 and September 2021 were reviewed. The main outcome was the rate of reoperation for infection of the cranioplasty. We evaluated risk factors for bone flap infection, rate of reoperation for any reason (hematoma, skin erosion, cosmetic request, or bone resorption), and radiological evidence of bone flap resorption.ResultsA total of 195 patients with a median age of 50 (interquartile range: 38.0–57.0) years underwent DC and AC between 2010 and 2021. Of the 195 bone flaps, 54 (27.7%) had a positive culture, including 48 (88.9%) with Cutibacterium acnes. Of the 14 patients who underwent reoperation for bone flap re-removal for infection, 5 and 9 had positive and negative bacteriological cultures, respectively. Of patients who did not have bone flap infection, 49 and 132 had positive and negative bacteriological cultures, respectively. There were no significant differences between patients with and without positive bacteriological culture of bone flaps in the rates of late bone necrosis and reoperation for bone flap infection.ConclusionsA positive culture of intraoperative osseous sampling during DC is not associated with a higher risk of re-intervention after AC.     

Cranioplasty with autologous cryopreserved bone after decompressive craniectomy. Complications and risk factors for developing surgical site infection

Background

Renewed interest has developed in decompressive craniectomy, and improved survival is shown when this treatment is used after malignant middle cerebral artery infarction. The aim of this study was to investigate the frequency and possible risk factors for developing surgical site infection (SSI) after delayed cranioplasty using autologous, cryopreserved bone.

Methods

This retrospective study included 74 consecutive patients treated with decompressive craniectomy during the time period May 1998 to October 2010 for various non-traumatic conditions causing increased intracranial pressure due to brain swelling. Complications were registered and patient data was analyzed in a search for predictive factors.

Results

Fifty out of the 74 patients (67.6 %) survived and underwent delayed cranioplasty. Of these, 47 were eligible for analysis. Six patients (12.8 %) developed SSI following the replacement of autologous cryopreserved bone, whereas bone resorption occurred in two patients (4.3 %). No factors predicted a statistically significant rate of SSI, however, prolonged procedural time and cardiovascular comorbidity tended to increase the risk of SSI.

Conclusions

SSI and bone flap resorption are the most frequent complications associated with the reimplantation of autologous cryopreserved bone after decompressive craniectomy. Prolonged procedural time and cardiovascular comorbidity tend to increase the risk of SSI.     

Decompressive craniectomy for severe traumatic brain injury: The relationship between surgical complications and the prediction of an unfavourable outcome

Object

To assess the impact that injury severity has on complications in patients who have had a decompressive craniectomy for severe traumatic brain injury (TBI).

Methods

This prospective observational cohort study included all patients who underwent a decompressive craniectomy following severe TBI at the two major trauma hospitals in Western Australia from 2004 to 2012. All complications were recorded during this period. The clinical and radiological data of the patients on initial presentation were entered into a web-based model prognostic model, the CRASH (Corticosteroid Randomization After Significant Head injury) collaborators prediction model, to obtain the predicted risk of an unfavourable outcome which was used as a measure of injury severity.

Results

Complications after decompressive craniectomy for severe TBI were common. The predicted risk of unfavourable outcome was strongly associated with the development of neurological complications such as herniation of the brain outside the skull bone defects (median predicted risk of unfavourable outcome for herniation 72% vs. 57% without herniation, p = 0.001), subdural effusion (median predicted risk of unfavourable outcome 67% with an effusion vs. 57% for those without an effusion, p = 0.03), hydrocephalus requiring ventriculo-peritoneal shunt (median predicted risk of unfavourable outcome 86% for those with hydrocephalus vs. 59% for those without hydrocephalus, p = 0.001), but not infection (p = 0.251) or resorption of bone flap (p = 0.697) and seizures (0.987). We did not observe any associations between timing of cranioplasty and risk of infection or resorption of bone flap after cranioplasty.

Conclusions

Mechanical complications after decompressive craniectomy including herniation of the brain outside the skull bone defects, subdural effusion, and hydrocephalus requiring ventriculo-peritoneal shunt were more common in patients with a more severe form of TBI when quantified by the CRASH predicted risk of unfavourable outcome. The CRASH predicted risk of unfavourable outcome represents a useful baseline characteristic of patients in observational and interventional trials involving patients with severe TBI requiring decompressive craniectomy.     

灭活自体颅骨回植钛铆钉固定的临床应用

目的 总结灭活自体颅骨回植以钛铆钉固定进行颅骨修补术的临床应用经验。方法 2000年3月至2003年12月对21例急性颅脑损伤等去骨瓣减压或颅骨本身受肿瘤侵蚀的患者，行自体颅骨普通冰箱冰冻保存后煮沸消毒，早期回植或受肿瘤侵蚀的骨瓣灭活后一期回植，以钛铆钉固定，随访观察修复效果。结果 所有病例伤口均一期愈合，无并发症发生，随访6个月至2年半，X射线片及CT显示回植骨瓣边缘吸收未超出钛铆钉固定范围，头颅外观及牢度良好，肿瘤无复发。结论 灭活自体颅骨回植进行颅骨修补术，方法简单、实用，利用钛铆钉固定可有效防止因回植骨瓣边缘吸收而导致的牢度下降。     

Cranioplasty: why throw the bone flap out?

Patients who undergo decompressive craniectomy for intracranial hypertension often require interval cranioplasty. Many cranioplasty agents are currently in use. The authors suggest that storage of the patient's own bone flap in the subcutaneous tissue of the abdominal wall, is a safe, efficacious and cost-effective alternative to use of synthetic cranioplasty materials.     

Relief of headache by cranioplasty after skull base surgery

Headache after skull base surgery can cause profound morbidity in certain patients, resulting in significant impairment of their quality of life. Several methods to prevent postoperative headache have been described, including a modification of the skin/muscle incision replacing the craniotomy bone flap replacing the bone flap and filling in the residual defect with methyl methacrylate, using hydroxyapatite cement (HAC) to fill the craniectomy defect, and wiring hardened methyl methacrylate (MMA) into the defect. Ten patients with severe headache following craniectomy for a posterior fossa lesion underwent cranioplasty with MMA, which was placed exactly within the craniectomy defect and secured rigidly with miniplates and screws. The headache decreased in severity in all patients and resolved completely in 90%. Also, 78% of patients with dizziness improved. The procedure and its effect on headache and dizziness will be described.     

Cranioplasty with inner table of bone flap. Technical note

A new method of cranioplasty is described in which the inner table of the bone flap obtained during craniotomy is used for grafting. The method was used in 10 cases to repair bone defects caused by a growing skull fracture in two, created during removal of an invasive skull tumor in two, during the approach to intraorbital tumors in two, and secondary to craniectomy for additional exposure in four. The method has the advantage that a piece of the inner table for grafting can be obtained from the craniotomy bone flap, without the need for an additional skin incision or taking a graft from another part of the body, and foreign-body reaction is minimal.     

The use of frozen autogenous bone flaps in delayed cranioplasty revisited

OBJECTIVE: To reevaluate the use of frozen autogenous bone flaps for patients undergoing delayed cranioplasty. METHODS: In the past 12 years, 49 patients have undergone delayed cranioplasty using frozen autogenous bone flaps. Bone flaps removed during the initial operation were sealed in three sterilized vinyl bags and stored at -35 degrees C (n = 37) or -84 degrees C (n = 12) for 4 to 168 days (mean, 50.6 d). The bone flaps were thawed at room temperature and replaced in their original positions. After cranioplasty, we monitored resorption of the bone flaps with computed tomography and evaluated the clinical and aesthetic results. Follow-up periods ranged from 14 to 147 months (mean, 59.2 mo). RESULTS: For 47 patients (95.9%), there were no complications during the follow-up period; there was slight thinning of the bone flap in some cases, but clinical and aesthetic results were highly satisfactory. Resorption was observed for a 12-year-old boy who had undergone cranioplasty, using two pieces of bone flap, 66 days after the initial operation. A 14-year-old boy with a cerebral contusion experienced a bone flap infection. Both patients underwent a second cranioplasty procedure, with ceramic plates. CONCLUSION: The clinical and aesthetic results of delayed cranioplasty using frozen autogenous bone flaps were satisfactory. The most important factor for success was excellent contiguity between the flap and the bone edge.     

Relief of Headache by Cranioplasty After Skull Base Surgery

Headache after skull base surgery can cause profound morbidity in certain patients, resulting in significant impairment of their quality of life. Several methods to prevent postoperative headache have been described, including a modification of the skin/muscle incision replacing the craniotomy bone flap replacing the bone flap and filling in the residual defect with methyl methacrylate, using hydroxyapatite cement (HAC) to fill the craniectomy defect, and wiring hardened methyl methacrylate (MMA) into the defect. Ten patients with severe headache following craniectomy for a posterior fossa lesion underwent cranioplasty with MMA, which was placed exactly within the craniectomy defect and secured rigidly with miniplates and screws. The headache decreased in severity in all patients and resolved completely in 90%. Also, 78% of patients with dizziness improved. The procedure and its effect on headache and dizziness will be described.     

Microbial contamination assessment of cryostored autogenous cranial bone flaps: should bone biopsies or swabs be performed?

Background

Autogenous cranioplasty infection requiring bone flap removal is under-recognised as a major complication causing significant morbidity. Microbial contamination of stored bone flaps may be a significant contributing factor. Current infection control practices and storage procedures vary. It is not known whether ‘superficial’ swabs or bone cultures provide a more accurate assessment.

Method

Twenty-five skull flaps that were cryo-stored for more than 6 months were studied. Two swab samples (superficial and deep) and a bone biopsy sample were taken from each skull flap sample and cultured. Half blood agar and half chocolate agar plates were inoculated with the swabs for anaerobic and aerobic cultures respectively. The bone biopsy samples were cultured in brain-heart broth and subcultured similar to the swabs for 5 days.

Results

Incidence of microbial contamination was 20 % in the bone flaps studied. One swab culture and five bone biopsy cultures were positive for bacterial growth, all of which contained Propionibacterium acnes (p?=?0.014). Positive cultures were from bone flaps stored less than 18 months, whereas no growth was obtained from bone flaps that were stored longer (p?=?0.014).

Conclusions

Bone biopsy culture is a more sensitive technique of assessing microbial contamination of cryo-stored autogenous bone flaps than swab cultures. The clinical implications of in vitro demonstration of microbial contamination require further study.     

Construction of titanium cranioplasty plate using craniectomy bone flap as template

In recent times a steady rise in cranioplasty operations has been noted because of increasing utilisation of decompressive craniectomy for trauma as well as stroke patients. A variety of techniques have been utilised for cranioplasty, with their own benefits and limitations. Titanium cranioplasty is one of the well-established and widely used techniques, with most centres utilising computer-assisted reconstruction for manufacture of titanium plates. In this paper we present a novel method for making titanium cranioplasty plates using the craniectomy bone flap as a template and the results of our experience. To date we have performed 51 cranioplasties using this method. The surgical results have been comparable to those obtained using the computer-assisted model technique. The construction cost for titanium cranioplasty plates using this method has been ￡360 cheaper per plate compared with the computer-assisted method. In addition, the CT workload and radiation exposure have been reduced.     

Preservation of bone flaps in patients with postcraniotomy infections

OBJECT: Management of postcraniotomy wound infections has traditionally consisted of operative debridement and removal of devitalized bone flaps followed by delayed cranioplasty. The authors report the highly favorable results of a prospective study in which postcraniotomy wound infections were managed with surgical debridement to preserve the bone flaps and avoid cranioplasty. METHODS: Since 1990, 13 patients with postcraniotomy wound infections have been prospectively treated with open surgical debridement and replacement of the bone flap. All patients received a full course of systemic antibiotic agents based on the determination of the bacterial culture and antibiotic sensitivity. Notable risk factors for infection included prior craniotomies, radiotherapy, and skull base procedures. The mean long-term follow-up period was 35 +/- 20 months. In all five patients who underwent craniotomies without complications, bone flap preservation was possible with full resolution of the infection and without the need for additional surgery. Among the eight patients with risk factors, bone preservation was possible in six patients, although two required minor wound revisions (without bone flap removal). Both patients who underwent craniofacial procedures required an additional procedure in which the bone flap was removed for recurrent infection (one after 2 months and the other after 29 months). CONCLUSIONS: In patients with uncomplicated postcraniotomy infections, simple operative debridement is sufficient and it is not necessary to discard the bone flaps and perform cranioplasties. Even patients with risk factors such as prior surgery or radiotherapy can usually be treated using this strategy. Patients who undergo craniofacial surgeries involving the nasal sinuses are at higher risk and may require bone flap removal.     

Histopathology of subcutaneously preserved autologous bone flap after decompressive craniectomy: a prospective study

Background

Limited reports are available regarding the viability of subcutaneously preserved autologous bone flaps after decompressive craniectomy. The present study was undertaken to evaluate the histopathological changes in these autologous bone flaps.

Methods

Between January 2011 and July 2012, 50 patients were prospectively studied at the time of cranioplasty. Bone flap retrieved from the abdominal wall was subjected to histopathological examination to look for mononuclear cell infiltration into the Haversian system, presence of osteocytes, osteoblastic activity, angiogenesis and new bone formation. Microbiological culture of bone specimens was also done.

Results

Of the 50 patients, there were 40 cases of trauma, 6 of aneurysmal bleed, 2 of tumor, and a single case of intracerebral hemorrhage and middle cerebral artery infarct, respectively. Mean age of the patients was 35.8 years (range, 10–64 years). Histopathological examination revealed the presence of osteocytes in 86 %, which indicates the viability of bone flaps. Osteoblastic activity was noted in 38 % and angiogenesis in 14 % of bone flaps, respectively. New bone formation was found in 6 %, and all had underlying osteoblastic activity. No significant correlation was found between the presence of osteocytes, osteoblasts, angiogenesis and duration of preservation of bone flaps. Acinetobacter species were cultured in a single patient. However, there was no evidence of clinical infection.

Conclusions

Subcutaneously preserved bone flap in the anterior abdominal wall remains viable and retains its osteogenic potential, and it is a simple, cost-effective option for storage of bone flaps during decompressive craniotomy. It has a negligible infection rate.     

Salvage of infected craniotomy bone flaps with the wash-in, wash-out indwelling antibiotic irrigation system. Technical note and case series of 12 patients

OBJECT: When complicated by infection, craniotomy bone flaps are commonly removed, discarded, and delayed cranioplasty is performed. This treatment paradigm is costly, carries the risks associated with additional surgery, and may cause cosmetic deformities. The authors present their experience with an indwelling antibiotic irrigation system used for the sterilization and salvage of infected bone flaps as an alternative to their removal and replacement. METHODS: The authors retrospectively reviewed the medical records for 12 patients with bone flap infections following craniotomy who received treatment with the wash-in, wash-out indwelling antibiotic irrigation system. Infected flaps were removed and scrubbed with povidone-iodine solution and soaked in 1.5% hydrogen peroxide while the wound was debrided. The bone flaps were returned to the skull and the irrigation system was installed. Antibiotic medication was infused through the system for a mean of 5 days. Intravenous antibiotic therapy was continued for 2 weeks and oral antibiotics for 3 months postoperatively. Wound checks were performed at clinic follow-up visits, and there was a mean follow-up period of 13 months. Eleven of the 12 patients who had undergone placement of the bone flap irrigation system experienced complete resolution of the infection. In five patients there was involvement of the nasal sinus cavities, and in four there was a history of radiation treatment. In the one patient whose infection recurred, there was both involvement of the nasal sinuses and a history of extensive radiation treatment. CONCLUSIONS: Infected bone flaps can be salvaged, thus avoiding the cost, risk, and possible disfigurement associated with flap removal and delayed cranioplasty. Although prior radiation treatment and involvement of the nasal sinuses may interfere with wound healing and clearance of the infection, these factors should not preclude the use of irrigation with antibiotic agents for bone flap salvage.     

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.