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.     

Bone flap salvage in acute surgical site infection after craniotomy for tumor resection

Craniotomy surgical site infections are an inherent risk and dreaded complication for the elective brain tumor patient. Sequelae can include delays in resumption in adjuvant treatments for multiple surgeries if staged cranioplasty is pursued. Here, the authors review their experience in operative debridement of surgical site infections with single-stage reimplantation of the salvaged craniotomy bone flap. A prospectively maintained database of a single surgeon’s neuro-oncology patients from 2009 to 2017 (JRF) was queried to identify 11 patients with surgical site infection after craniotomy for tumor resection. All patients underwent a protocol of aggressive operative debridement including drilling the bone edges and intraoperative flap sterilization with single-stage reimplantation, followed by tailored-antibiotic therapy. Ten of the 11 patients with frankly contaminated bone flaps from surgical site infection were able to be salvaged in a single-stage procedure. Five of these patients underwent adjuvant chemotherapy and/or radiation without secondary complication. There was one treatment failure in a delayed fashion which required additional surgery for craniectomy; however, this occurred after adjuvant treatment was administered. Surgical debridement and bone flap salvage is safe and cost-effective in managing acute surgical site infections after craniotomy for tumors. Additionally, this practice is likely beneficial in expediting the resumption of cancer therapy.     

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.     

Bone flap storage following craniectomy: a survey of practices in major Australian neurosurgical centres

Introduction: The resurgence of decompressive craniectomy surgeries for management of intracranial hypertension has led to a parallel increase in cranioplasty procedures for subsequent reconstruction of the resultant extensive skull defects. Most commonly, cranioplasties are performed using the patients' own cryopreserved skull flaps. Currently, there are no standardized guidelines for freeze‐storage of bone flaps either nationally or internationally. In this initial study, the authors surveyed major neurosurgical centres throughout Australia to document current clinical practices. Methodology: Twenty‐five neurosurgical centres affiliated with major public, teaching hospitals in all Australian states were included in the current survey study. A standardized survey guide incorporating standardized questions was used for data collection either by phone interviews and/or electronic (email) communication. Details regarding bone flap preparation following craniectomy, temperature and duration of freeze‐storage, infection control/micro‐contamination detection protocols, pre‐implantation procedures were specifically recorded. Results: Cranioplasty using cyropreserved autogenous bone flaps remains the most common (96%) mode of skull defect reconstruction in major neurosurgical centres throughout Australia. Following the initial craniotomy, the harvested skull flaps were most frequently (88%) double‐ or triple‐bagged under dry, sterile conditions. In 16% of hospitals, skull flaps were irrigated either with antibiotic mixed‐saline or Betadine prior to cryopreservation. Skull biopsies or swabs were obtained from the skull flaps for micro‐contamination studies in accordance with departmental protocol in 68% of hospitals surveyed. Subsequently, the bone flaps were cryopreserved at wide ranging temperatures between ?18°C to ?83°C, for variable time intervals (6 months to ‘until patient deceased’). Twelve neurosurgical centres (48%) elected for bone flap storage to be undertaken at the local bone bank. In the remainder (52%) of the hospitals, bone flaps were cryopreserved in locally maintained freezers. Prior to re‐implantation of the skull flaps at subsequent cranioplasty surgeries, six (24%) of the neurosurgical centres had specific thawing procedures involving immersion of the frozen bone flaps in Ringer's solution and/or Betadine. Further pre‐implantation bacteriological cultures from bone biopsies or swabs were obtained only in three (12%) hospitals. Conclusions: This study has documented highly varied skull flap cryopreservation and storage practices in neurosurgical centres throughout Australia. These differences may contribute to relatively high complication rates of infection and bone resorption reported in the literature. The results of the current study argue for the further need of high quality clinical and basic science research, which aims to characterize the effect of current skull flap management practices and freeze‐storage conditions on the biological and biomechanical properties of skull bone.     

Repositioning of Cranial Bone Flaps Cut with a Diamond-Coated Threadwire Saw: 5-Year Experience with Cosmetic Cranioplasty without Fixation Devices

Artificial fixation systems for cranial bone flaps have problems related to their materials and designs. We developed an alternative technique for supratentorial craniotomy that employs a diamond-coated threadwire saw (diamond T-saw), originally developed for spinal surgery, and reduces the bone gap for fitted bone flap fixation. The study subjects were 77 adults undergoing elective supratentorial craniotomy. After placing a burr hole at each corner of the craniotomy, we performed osteotomy between adjacent burr holes to approximately one-third of the length of the osteotomy with a craniotome; this leaves a bony bridge at each corner. The diamond T-saw was introduced between adjacent burr holes through the epidural space and a bridge was cut with reciprocating strokes. On closure, the bridge firmly supports the flap and only sutures are needed for fixation. Successful bone flap fixation was obtained in all followed-up cases. There were no technique-related complications such as dural laceration, flap displacement, or resorption. Our method is ideal for bone cuts in cosmetic cranioplasty; it is easy, safe, and inexpensive and avoids the need for flap fixation with artificial devices.     

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.     

Histopathologic and microdensitometric analysis of craniotomy bone flaps preserved between abdominal fat and muscle

In this study we have investigated the preservation of craniotomy bone flaps within the abdominal wall and the use of such bone flaps for cranioplasty in the early post-operative period. The craniotomy flaps were implanted into a “pocket” between abdominal fat and muscle of adult rabbits, and were later used as autologous grafts in cranioplasty. The flaps were analyzed by histopathologic and microdensitometric methods. In 36 of the flaps, new bone formation near the periosteum was observed. The bone flap-cranium relationship was supplied by a bony tissue. Microdensitometric analysis showed increased optic densities in the experimental group.     

Simple reconstruction of frontal sinus opened during craniotomy using small autogenous bone piece: technical note

BACKGROUND: Accidental opening of the frontal sinuses during craniotomy can lead to various postoperative complications. We report a simple and reliable reconstruction method using no exogenous or autogenous material obtained from another site. METHODS: This method involves packing a small wedge-shaped piece of bone obtained from the bone flap of the craniotomy into the nasal recess of the exposed sinus. The large opened frontal sinus is reconstructed as a new minimized frontal sinus with mucous membrane and bony roof in the nasal recess. RESULTS: Eleven patients with large frontal sinus opening during craniotomy (7 cases of bifrontal craniotomy for the basal interhemispheric approach) underwent frontal sinus reconstruction by packing of a small bone piece into the nasal recess. No patients suffered postoperative complications related to the opened frontal sinus such as pneumocephalus or cerebrospinal fluid rhinorrhea. CONCLUSIONS: Packing of a small bone piece from the bone flap is a quick and reliable method to reconstruct the frontal sinus opened during craniotomy.     

Free rectus abdominis muscle reconstruction of the anterior skull base.

Pericranial flaps and galeal frontalis myofascial flaps can be useful for separating the cranial space from the paranasal sinuses and the nasopharynx, but they cannot provide reliable separation and protection of the brain from bacterial flora of the upper airway in patients who previously have received high dose radiation therapy and undergone craniotomy, or required extensive resection of the cranial base. The free rectus abdominis muscle flap, on the other hand, can provide a good alternative for reconstruction of the anterior skull base in such difficult cases, and give good results. In six cases using free rectus abdominis flaps, there have been neither cerebrospinal fluid leaks nor meningitis. There was one flap failure due to venous congestion.     

Two-bone flap craniotomy for the transpetrosal–presigmoid approach to avoid a bony defect in the periauricular area after surgery on petroclival lesions: technical note

The authors describe a two-bone-flap craniotomy technique to avoid the bone defect caused by the transpetrosal–presigmoid approach. Briefly, this technique includes three steps. The first step is to elevate a temporoparietal bone flap located superiorly to the transverse and sigmoid sinuses. The second step is to dissect the transverse and sigmoid sinuses away from the bone by inserting a gelatin sponge. This maneuver provides hemostasis and protects the sinuses from injury. The third step is to cut a second bone flap including part of the temporal bone and the outer table of the mastoid bone with a high-speed drill system. After the operation, the two bone flaps are fixed in place with titanium osteosynthesis fixation material. This approach provides a simple, easy, and safe technique for the transpetrosal–presigmoid approach. The technique has been performed in 83 patients treated for petroclival neoplasms with excellent cosmetic results.     

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.     

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.     

Behandlung der Knocheninfektion im Bereich des Schädels

Osteomyelitis in the skull region is encountered preferably as a postoperative, but also as a posttraumatic lesion, furthermore it occurs in case of infection of the paranasal sinuses or, rarely, as hematogenic metastasis. The routine treatment comprises a careful wound cleaning with excision of fistula, resection of the osteomyelitic bone and ablation of all purulent and devital tissues, eventually sanitation of an infected paranasal sinus. Between six and twelve months after the healing of the infection, the bone defect is closed by plastic surgery. In 1976, we have introduced Refobacin-Palacos R for the local treatment of the infection with simultaneous definitive closing of the bone defect in case of osteomyelitis of the skull [9]. 44 patients have been treated since with this method. The rate of reinfection was 3% in osteomyelitis of the calotte without involvement of the sinuses and 25% in case of involvement of the frontal sinuses. A twofold method has been developed in order to reduce the relatively high frequency of reinfection in case of involvement of the frontal sinuses. The wound cleaning with revision of the frontal sinuses and parenteral administration of antibiotic drugs was performed as usual. An additional local treatment of the infected frontal sinuses was performed by implantation of Septopal chains which were removed ten to fourteen days later. During the same session the nasal excretory ducts were closed and the frontal sinuses largely filled up with muscle pieces together with a compound of spongiosa, fibrin, and antibiotic. The remaining bone gap was closed with Refobacin-Palacos R. A significantly decreased reinfection rate is anticipated with this twofold procedure, however, a clear statement is not yet possible due to the small number of cases and the relatively short follow-up period.     

Actinomycosis complicating fibula flap mandible reconstruction: a report of two cases.

Two patients undergoing fibula flap mandible reconstruction developed chronic intraoral wounds and salivary fistulae. After initial attempts at salvage, tissue biopsies demonstrated Actinomycosis infection. With antibiotic treatment and debridement, one reconstruction was salvaged while one was lost. Actinomycosis infection should be considered a possible agent in chronic wounds complicating mandible reconstructions with microsurgical flaps.     

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.     

Experimental evaluation of free-tissue transfer to promote healing of infected wounds in dogs

An experimental model was designed to evaluate the course of healing and the changes in bacterial concentrations of infected forelimb wounds with devascularized bone in dogs. Infected leg wounds were allowed to heal by secondary intention or were covered with a full-thickness or split-thickness skin graft, an epigastric skin/fat flap, or a gracilis musculocutaneous flap. All skin grafts failed. Gracilis muscle flaps were superior to epigastric skin/fat flaps in decreasing soft-tissue bacterial concentrations. Quantitative bone cultures, however, were positive at reexploration 6 weeks later in 33% of all legs covered with a flap. X-ray films were successful in predicting the presence or absence of bone infection in 70% of all legs. Postmortem arteriograms of legs covered with muscle flaps showed neovascularity to bone. This study suggests muscle flap coverage of wounds debrided of contaminated, necrotic, or infected bone and soft tissue to be an excellent method of providing well-vascularized soft tissue promoting healing and resolution of infection.     

小腿肿瘤保肢术皮肤缺损的修复

目的：比较游离皮瓣和局部皮瓣转移对于肢体肿瘤保肢术中皮缺损修复的安全性。方法：1995年9月-1999年10月，分别用游离皮瓣移植和局部皮瓣转移修复15例小腿恶性骨肿瘤和软组织肿瘤保肢术后形成的皮缺损，9例游离皮瓣移植，6例局部旋转皮瓣。结果：游离皮瓣移植切口均一期愈合，无感染，皮瓣坏死，化疗对游离皮瓣成活无影响。6例局部皮瓣3例在术后5d出现皮瓣循环障碍，皮瓣坏死，伤口开裂，灭活的肿瘤骨外露。结论：小腿肿瘤保肢治疗中，采用局部皮瓣安全性较差。带血管蒂皮瓣游离移植是小腿肿瘤保肢术修复皮肤缺损的理想方法。     

Temporary intentional leg shortening and deformation to facilitate wound closure using the Ilizarov/Taylor spatial frame

Infected tibial nonunions with bone loss pose an extremely challenging problem for the orthopaedic surgeon. A comprehensive approach that addresses the infection, bone quality, and overlying soft-tissue integrity must be considered for a successful outcome. Acute shortening with an Ilizarov frame has been shown to be helpful in the treatment of open tibia fractures with simultaneous bone and soft-tissue loss. Cases in which the soft-tissue defect considerably exceeds bone loss may require an Ilizarov frame along with a concomitant soft-tissue procedure; however, there are a number of potential difficulties with vascularized pedicle flaps and free tissue flaps, including anastomotic complications, partial flap necrosis, and flap failure. The technique described in this report involves acute shortening and temporary bony deformation with the Ilizarov apparatus to facilitate wound closure and does not require a concomitant soft-tissue reconstructive procedure. Once the wound is healed, osseous deformity and length are gradually corrected by distraction osteogenesis with the Ilizarov/Taylor Spatial frame.     

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.     

A simple technique for expansive suboccipital cranioplasty following foramen magnum decompression for the treatment of syringomyelia associated with Chiari I malformation

The benefits of osteoplastic suboccipital craniotomies over the traditional suboccipital craniectomies have been recognized. We describe a simple method of expansive suboccipital cranioplastic craniotomy using a free bone flap and report satisfactory clinical results in 16 patients with syringomyelia associated with Chiari I malformation. A free suboccipital bone flap is created from the rostral part of the occiput by placing two to four burr holes and connecting them with a craniotome. The posterior bony margin of the foramen magnum and the posterior arch of C1 are removed thereafter. Then dural plasty using a patch graft of dural substitutes is performed. The expansive suboccipital cranioplasty is performed by positioning the free bone flap caudal to the original location and fixing it with titanium miniplates to construct a bony frame to cover the foramen magnum. The rostral part of the cranial defect is filled with bone chips created during the craniotomy. Sixteen patients underwent this procedure. There was no operative mortality and no major complication, such as persistent pseudomeningocele. Preoperative symptoms improved significantly in all patients except for one who had persistent dysesthetic pain. Our simple method of expansive suboccipital cranioplasty for the treatment of syringomyelia associated with Chiari I malformation proved useful and achieved satisfactory long-term results.