Cranioplasty Infections—Adding Insult to Injury

Polyetheretherketone (PEEK) Into the Future: Lowering Infection Rates in Cranioplasty

INTRODUCTION

Surgical site infection (SSI) is one of the most common complications following cranioplasty. At our institution, 3D printing has emerged as a popular option for creating customized polyetheretherketone (PEEK) cranioplasty implants that are lower profile than older, non-3D-printed implants. The 3D-printed implants can be integrated, with fixation plates already attached, or nonintegrated, with separate fixation plates available. To our knowledge, no study has analyzed the differences in infection rates between integrated and nonintegrated 3D-printed implants.

OBJECTIVES

This study aimed to explore whether integrated 3D-printed cranioplasty implants lead to decreased infection risk and improved patient outcomes compared to nonintegrated 3D-printed implants and further aims include exploring how operating room time and hospital length of stay affect infection risk.

METHODS

A retrospective chart review of 197 patients who underwent cranioplasty surgery from 2012 to 2023 was conducted. The postcranioplasty infection rate was compared between the integrated and nonintegrated 3D implants. Pre- and postoperative antibiotic use, operating time, hospital stay length, and patient comorbidities were also evaluated. Statistical analysis was conducted using SPSS version 28.0 (IBM Corp., Armonk, NY). Initial bivariate statistics were utilized where appropriate, and ultimately, a binary logistic regression model was employed.

RESULTS

Our overall infection rate was 12.2%, higher than the national average of 7.89%. There was no significant association between the implant type and postcranioplasty infection. However, when controlling for the clinical and demographic covariates in our study, patients who had a Charlson comorbidity index (CCI) of 3-4 were 6.36 times as likely to experience a postcranioplasty infection when compared to their counterparts with a CCI of 0, OR of 6.36, 95% CI of 1.01-40.0, and a p value of 0.048. Additionally, with every one-year increase in age, the number of infections decreased by 0.955, with an OR of 0.955, 95% CI of 0.915-0.996, and a p value of 0.031.

CONCLUSIONS

While there was no significant difference in SSI between the integrated and nonintegrated 3D-printed PEEK implants, elevated CCI and age were associated with a greater risk of infection. Our overall infection rate exceeds that reported in a recent large-scale review, which may be attributable to the higher average CCI typically observed in our tertiary care setting. Our findings illustrate that integrated and nonintegrated 3D implants offer viable and efficacious options for patients with cranial vault deformities requiring surgical repair.

Post-Cranioplasty Complications: Lessons From a Prospective Study Assessing Risk Factors

ABSTRACT

Complication rate related with cranioplasty is described as very high in most of relevant studies. The aim of our study was to try to identify possible factors, that could predict complications following cranioplasty. The authors hypothesized that some physical characteristics on the preoperative brain computed tomography (CT) scan can be predictive for complications.The authors carried out a prospective observational study. All patients were adults after decompressive craniectomy, planned for cranioplasty and had a brain CT scan the day before cranioplasty. Our data pool included demographics, reason of craniectomy, various radiological parameters, the time of cranioplasty after craniectomy, the type of cranioplasty bone flap, and the complications.Twenty-five patients were included in the study. The authors identified statistically significant correlation between time of cranioplasty after craniectomy and the complications, as well as between the type of cranioplasty implant and the complications. There was statistically significant correlation between complications and the distance of the free brain surface from the level of the largest skull defect dimension - free brain surface deformity (FBSD). Moreover, the correlation between FBSD and the time of cranioplasty was statistically significant.It seems that for adult patients with unilateral DC the shorter time interval between craniectomy and cranioplasty lowers the risk for complications. The risk seems to be decreased further, by using autologous bone flap. Low values of the FBSD increase the risk for complications. This risk factor can be avoided, by shortening the time between craniectomy and cranioplasty.

Treatment of Osteomyelitic Bone Following Cranial Vault Reconstruction With Delayed Reimplantation of Sterilized Autologous Bone: A Novel Technique for Cranial Reconstruction in the Pediatric Patient

ABSTRACT

Craniosynostosis, a deformity of the skull caused by premature fusion of ≥1 cranial sutures, is treated surgically via endoscopic approaches or cranial vault remodeling. Postoperative infection is rare. Management of postoperative surgical site infections often involves culture-directed intravenous antibiotics and debridement, with removal of osteomyelitic bone and hardware in refractory cases. Removal of autologous bone in a pediatric patient presents a reconstructive challenge, as alloplastic options are not optimal in a growing child, especially in the setting of infection. Moreover, infants and small children have limited autologous bone options for reconstruction. We present our case of a young child who developed an infectious complication following cranial vault remodeling. The patient's demographic information, clinical presentation and postoperative course, radiologic features, surgical interventions, and treatment outcomes were reviewed. In our case, autologous osteomyelitic bone underwent tissue processing to eradicate the infection and complete skull reconstruction using the patient's own processed autologous bone was performed in a delayed fashion. The patient is now 1 year postoperative with no recurrence of infection. We present this case as a novel technique to eradicate infection in autologous bone, allowing for delayed autologous cranial reconstruction.

Cryostored autologous skull bone for cranioplasty? A study on cranial bone flaps' viability and microbial contamination after deep-frozen storage at -80°C

Craniectomy is a life-saving procedure. Subsequent cranioplasty with autologous skull bone has a bone resorption rate from 4% to 22.8% and an infection rate from 3.3% to 26%. There are concerns with their viability and the potential microbial contamination as they were explanted for a long period of time. Eighteen cranial bone flaps stored at Prince of Wales Hospital Skull Bone Bank during the period from June 2011 to March 2016 were identified. Ethics approval was obtained. Bone chips and deep bone swabs were collected for osteoblast culture and microbial culture. Skull Bone Bank was kept at -80°C under strict aseptic technique during the study period. The storage period ranged from 4months to 55months. For the osteoblast culture, all eighteen bone flaps had no viable osteoblast growth. For the bacterial culture, five had positive bacteria growth (27.8%). Three were Pasteurella multocida and two were Methicillin-resistant Staphylococcus aureus. The mean duration of storage of the infected bone flap was 32.9months (±15.1months) versus 19.9months (±17.9months) of those bone flaps with no bacterial growth (p=0.1716). The mean size of the infected versus non-infected bone flaps was 117.7cm² (±44.96cm²) versus 76.8cm² (±50.24cm²) respectively (p=0.1318). Although in this study statistical significance was not reached, it was postulated that infected bone flaps tended to be larger in size and had a longer duration of storage. In conclusion, cryostored skull bone flaps beyond four months showed no viable osteoblasts. Bacterial contamination rate of bone flaps was 27.8% in this study.

Polymethylmethacrylate imbedded with antibiotics cranioplasty: An infection solution for moderate and large defects reconstruction?

Background:

In cases where autologous bone graft reconstruction is not possible (such as comminuted fractures, bone graft reabsorption, or infection) and the use of synthetic material is required, polymethylmethacrylate (PMMA) use is a safe and efficient solution. Studies comparing the incidence of postoperative complications between autologous and synthetic cranioplasty are heterogeneous, not allowing a conclusion of which is the best material for skull defects reconstruction. Current medical literature lacks prospective well-delineated studies with long-term follow-up that analyze the impact of antibiotic use in PMMA cranial reconstruction of moderate and large defects.

Methods:

A prospective series of patients, who underwent cranioplasty reconstruction with PMMA impregnated with antibiotic, were followed for 2 years. Authors collected data regarding demographic status, clinical conditions, surgical information, and its complications.

Results:

A total of 58 patients completed full follow-up with a mean group age of 40 years and a male predominance (77%). Major complications that required surgical management were identified in 5 patients, and 10 patients evolved with minor complications. Postoperative surgical site infection incidence was 3.2%.

Conclusion:

The infection rate in patients submitted to PMMA flap cranioplasty impregnated with antibiotic is significantly inferior comparing to the data described in medical literature. A lower infection incidence impacts secondary endpoints such as minimizing surgical morbidity, mortality, hospitalization period, and, consequently, costs.

Repair of a Complicated Calvarial Defect: Reconstruction of an Infected Wound With rhBMP-2

BACKGROUND

Management of the previously infected craniofacial defect remains a significant clinical challenge, posing obstacles such as wound healing complications, lack of donor site availability, and predisposition to failure of the repair. Optimal therapy would reconstruct like with like, without donor site morbidity. The purpose of this study was to compare the efficacy of recombinant human bone morphogenetic protein-2 (rhBMP-2)-mediated bone regeneration with the current standard of autologous bone graft for repair of previously infected calvarial defects.

METHODS

Nineteen adult New Zealand white rabbits underwent subtotal calvariectomy. Bone flaps were inoculated with Staphylococcus aureus and replanted. After 1 week of infection, bone flaps were removed, and wounds were debrided, followed by 10 days of antibiotic treatment. After 6 weeks, animals underwent scar debridement followed by definitive reconstruction in 1 of 4 groups: empty control (n = 3), vehicle control (buffer solution on absorbable collagen sponge [ACS], n = 3), autologous bone graft (n = 3), or rhBMP-2 repair (rhBMP-2/ACS, n = 10). Animals underwent computed tomography imaging at 0, 2, 4, and 6 weeks postoperatively, followed by euthanization and histological analysis. Percent healing was determined by 3-dimensional analysis. A (time × group) 2-way analysis of variance was performed on healing versus treatment group and postoperative time.

RESULTS

At 6 weeks postoperatively, rhBMP-2/ACS and autologous bone graft resulted in 93% and 68% healing, respectively, whereas the empty and vehicle control treatment resulted in 27% and 26% healing (P < 0.001). Histologically, compared to autologous bone graft, bone in the rhBMP-2/ACS group was more cellular and more consistently continuous with wound margins.

CONCLUSIONS

The rhBMP-2 therapy is effective in achieving radiographic coverage of previously infected calvarial defects.

Analysis of Decompressive Craniectomies with Subsequent Cranioplasties in the Presence of Collagen Matrix Dural Substitute and Polytetrafluoroethylene as an Adhesion Preventative Material

OBJECTIVE

Decompressive craniectomy is an established treatment for malignant intracranial hypertension. Cranioplasty is performed once cerebral swelling has resolved. Complications include infection, postoperative fluid collections, hematoma, reoperation, and seizures. Our experience using a double layer technique during craniectomy with a collagen matrix onlay dural substitute and expanded polytetrafluoroethylene for antiadhesive properties during cranioplasty was reviewed.

METHODS

This is a retrospective chart review of 39 consecutive patients who underwent craniectomy with placement of collagen matrix dural onlay and expanded polytetrafluoroethylene and subsequent cranioplasty. Demographic data, size of craniectomy defect, estimated blood loss, operative time, time between operations, presence of dural tackups, and postoperative complications were analyzed.

RESULTS

Mean operative time was 132 minutes and estimated blood loss was 112 mL. Overall complication rate was 25.6% and no mortality was encountered. Nine patients had postoperative fluid collections measuring ≥ 10 mm in thickness and/or 5 mm of midline shift. Two patients required reoperation for these collections. Two patients developed infections requiring bone flap removal. Three patients developed seizures after cranioplasty. Five patients required shunt placement for hydrocephalus.

CONCLUSIONS

Our dual layer closure technique at time of decompressive craniectomy carries a similar reduction in operative time and estimated blood loss when compared with cranioplasty series with other antiadhesives present. The technique described enables easy dissection of the musculocutaneous flap from the dural plane during cranioplasty and increases the safety of the operation.

Analysis of Factors Contributing to Infections After Cranioplasty: A Single-Institution Retrospective Chart Review

OBJECTIVE

Cranioplasty is one of the most common neurosurgical procedures, yet has one of the greatest rates of infection among cranial operations. Although studies have reported on cranioplasty complications, it is unclear what factors contribute to the high rate of infection. This study aims to determine which patient characteristics and operative factors lead to postcranioplasty infections.

METHODS

This was a retrospective chart review of 186 patients. Factors analyzed included sex, reason for cranioplasty, type of infection, medical comorbidities, and surgical factors.

RESULTS

The overall infection rate was 24%. Skin flora was the most common pathogen. Wound dehiscence and presence of a postoperative fluid collection were associated significantly with a greater rate of infection (P < 0.001), whereas the use of autologous bone flap and a state of immunosuppression trended toward statistical significance (P = 0.075 and P = 0.089, respectively). Male sex, history of previous infection, history of craniectomy for trauma, cranioplasty size, and time to cranioplasty were not found to be significant factors related to cranioplasty infection.

CONCLUSIONS

Although wound dehiscence and postoperative fluid collections were associated significantly with infection in this study, the number in each sample size was small, and further studies with a larger number of patients in each subgroup is necessary to validate our findings.