Removal of symptomatic titanium fixation plates after craniotomy

Penetration of the Scalp by the Bent Fragment of a Pre-installed Titanium Mini-Plate Due to a Minor Head Injury: A Case Report

Titanium mini-plates are commonly used for bone flap fixation in craniotomy and are particularly essential for covering burr holes. Plate exposure through the scalp may occur because of scalp thinning caused by infection or local ischemia, and penetration of the scalp by a titanium mini-plate that had been bent by a minor head injury are rare. A 69-year-old man who had undergone covering of a burr hole in the calvarium by a titanium plate for clipping of a ruptured aneurysm 17 years ago was referred to our clinic to examine metal protruding through the scalp. One year previously, he had hit his head on a wall with no consequence until one week ago, when he noted the protruding metal. Plain skull radiography showed that a portion of the pinwheel-shaped titanium mini-plate had been bent upward and was exposed through the scalp. As the wound was contaminated with sebum, the plate and three screws securing it were removed through a linear skin incision under local anesthesia. The wound healed uneventfully, and the sutures were removed 10 days later. Bone flap fixation requires careful attention. When a five-screw hole pinwheel-shaped titanium mini-plate is used to cover a burr hole, all five holes should be fixed to the skull/bone flap to prevent bending in the future. Alternatively, a wing that is not fixed with a screw should be cut or a rectangular or diamond-shaped plate should be used.

Stem Cell-Laden Engineered Patch: Advances and Applications in Tissue Regeneration

Stem cell-based therapies are emerging as significant approaches in tissue engineering and regenerative medicine, applicable to both fundamental scientific research and clinical practice. Despite remarkable results in clinical studies, challenges such as poor standardization of graft tissues, limited sources, and reduced functionality have hindered the effectiveness of these therapies. In this review, we summarize the engineering approaches involved in fabricating stem cell assisted patches and the substantial strategies for designing stem cell-laden engineered patches (SCP) to complement the existing stem cell-based therapies. We then outline the potential applications of SCP in advancing tissue regeneration and regenerative medicine. By combining living stem cells with engineered patches, SCP can enhance the functions of both components, particularly for tissue engineering applications. Finally, we addressed current challenges, such as ethical considerations, high costs, and regulatory hurdles and proposed future research directions to overcome these barriers.

Multicenter Randomized Controlled Clinical Trial to Compare the Safety and Performance of Two Bone Flap Fixation Systems

BACKGROUND AND OBJECTIVES

Polymeric clamp-like devices present potential advantages regarding plates and screws to close craniotomies; however, no clinical research has provided enough evidence to compare them. This randomized controlled trial compares the clinical safety and performance of clamp-like devices with the standard of care for craniotomy closure: titanium plates and screws (P&S).

METHODS

A prospective, double-arm, multicenter randomized controlled trial was performed at 3 sites, recruiting 60 patients undergoing neurosurgical interventions requiring craniotomy. Patients were randomly allocated to 2 groups depending on the bone flap fixation system to be used: plates and screws (any brand) and clamp-like devices (Cranial LOOP, NEOS Surgery S.L.). The primary end point of the study (bone flap alignment) was assessed 6 months after surgery through neuroimaging. Secondary end points included adverse events and device deficiency assessment, closure method usability assessed by the surgeon, and patient-reported device-related inconveniences.

RESULTS

It was necessary to use a median of 3 Cranial LOOP and 4 plates and 8 screws to close craniotomies. All patients from both groups had equally good bone flap alignment. Most implantations were reported as easy or very easy for both groups, and surgeons were generally satisfied or very satisfied with both treatments. No related adverse events have been reported for any of the treatment groups. Two patients reported discomfort or protuberances caused by P&S; no inconveniences were reported for Cranial LOOP.

CONCLUSION

Cranial LOOP performance is equal to P&S for fixation of the cranial bone flap. In addition, it presents some advantages, such as the use of a lower number of devices, potentially making this system more affordable, and the lack of discomfort previously linked with the use of P&S.

Free bone flap reconstruction in retrosigmoid approach for microvascular decompression: a comparative cohort study

Titanium plates and screws are common material used for rigid bone flap fixation after retrosigmoid craniotomy such as microvascular decompression (MVD). We conducted this study to evaluate outcomes of the free bone flap cranioplasty without fixation in MVD and compared its postoperative complication rate with routine methods. We retrospectively reviewed all patients who underwent MVD at our institution from May 2017 to August 2022. Patients were divided into two groups according to whether the bone flap was fixed or not. Follow-ups periods spanned 6-28 months after the operation. Of 189 patients who underwent MVDs via retrosigmoid approach, 79 cases (42%) had their bone flaps replaced without titanium fixation after craniotomies (< 3 cm x 3 cm). Compared to fixed bone flap group, free bone flap group had shorter operative time (105.56 ± 15.87 min vs. 113.72 ± 17.80 min, P = 0.001), less in-patient costs (¥23059.66 ± 4488.54 vs. ¥27714.82 ± 2705.74, P < 0.001), and less proportion of postoperative headache and incisional pain (43.0% vs. 60.9%, P = 0.015). One case of incisional cerebrospinal fluid leak happened in free bone flap group while one case of incisional infection happened in fixed bone flap group. No statistical difference in bone flap displacement, duration of postoperative hospital stays or complication rate was found between the two groups. Nineteen patients in free bone flap group received long-term CT follow-up and all were proved to have good skull union. This study proves that free bone flap cranioplasty in MVD without titanium plate fixation can shorten the operation time and reduce hospitalization expenditure without increasing complication rates.

Expanding Our Role in Headache Management: A Systematic Review and Algorithmic Approach to Surgical Management of Postcraniotomy Headache

BACKGROUND

Chronic postcraniotomy headache (PCH) is common and debilitating. Unfortunately, the literature on this topic is sparse without clear management algorithms. Possible etiologies of PCH include nerve injury and/or entrapment, hardware, dural adhesions, or musculoskeletal injury. The purpose of this study was to present the results of both a systematic review of the literature and a single-center case series, both of which informed the development of a novel treatment algorithm that may be applied to this patient population.

METHODS

Using Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, we performed a systematic review of the literature, identifying articles describing the surgical management of PCH. A retrospective chart review was performed to identify patients who met the criteria for PCH treated at our institution. A patient's history and physical examination determined the etiology and management, and pain severity scores were the primary outcome measured.

RESULTS

Nineteen articles encompassing 131 patients described surgical management techniques for PCH. 83 patients (63.3%) had complete resolution of pain (χ2 = 52.1, P < 0.0001). At our institution, 19 patients underwent surgical management for PCH. A significant reduction in pain scores from 7.57 to 2.16 (P < 0.001) was demonstrated, and 84 percent of patients achieved complete or significant pain reduction.

CONCLUSIONS

Through a literature review and our own case series, we demonstrate that surgical management of PCH can achieve remarkable results. Plastic surgeons, with their expanding role in treating migraine and headaches, are well suited to manage these patients. We present an algorithmic approach to simplify the management of this common and debilitating condition.

Frontotemporal Craniotomy for Clipping of Unruptured Aneurysm Using a Diamond-Coated Thread Wire Saw and Reconstruction Using Calcium Phosphate Cement without Metal Fixation

Metal fixation systems for cranial bone flaps cut by a drill are convenient devices for cranioplasty, but cause several complications. We use modified craniotomy using a fine diamond-coated threadwire saw (diamond T-saw) to reduce the bone defect, and osteoplasty calcium phosphate cement without metal fixation. We report our outcomes and tips of this method. A total of 78 consecutive patients underwent elective frontotemporal craniotomy for clipping of unruptured intracranial aneurysms between 2015 and 2019. The follow-up periods ranged from 13 to 66 months. The bone fixation state was evaluated by bone computed tomography (CT) and three-dimensional CT (3D-CT). The diamond T-saw could minimize the bone defect. Only one wound infection occurred within 1 week postoperatively, and no late infection. No pain, palpable/cosmetically noticeable displacement of the bone flap, fluid accumulations, or other complications were observed. The condition of bone fixation and the cosmetic efficacy were thoroughly satisfactory for all patients, and bone CT and 3D-CT demonstrated that good bone fusion. No complication typical of metal fixation occurred. Our method is technically easy and safety, and achieved good mid-term bone flap fixation in the mid-term course, so has potential for bone fixation without the use of metal plates.

Cranial flap fixation in sheep using a resorbable bone adhesive

OBJECTIVE

The authors' goal in this study was to investigate the use of a novel, bioresorbable, osteoconductive, wet-field mineral-organic bone adhesive composed of tetracalcium phosphate and phosphoserine (TTCP-PS) for cranial bone flap fixation and compare it with conventional low-profile titanium plates and self-drilling screws.

METHODS

An ovine craniotomy surgical model was used to evaluate the safety and efficacy of TTCP-PS over 2 years. Bilateral cranial defects were created in 41 sheep and were replaced in their original position. The gaps (kerfs) were completely filled with TTCP-PS (T1 group), half-filled with TTCP-PS (T2 group), or left empty and the flaps fixated by plates and screws as a control (C group). At 12 weeks, 1 year, and 2 years following surgery, the extent of bone healing, local tissue effects, and remodeling of the TTCP-PS were analyzed using macroscopic observations and histopathological and histomorphometric analyses. Flap fixation strength was evaluated by biomechanical testing at 12 weeks and 1 year postoperatively.

RESULTS

No adverse local tissue effects were observed in any group. At 12 weeks, the bone flap fixation strengths in test group 1 (1689 ± 574 N) and test group 2 (1611 ± 501 N) were both statistically greater (p = 0.01) than that in the control group (663 ± 385 N). From 12 weeks to 1 year, the bone flap fixation strengths increased significantly (p < 0.05) for all groups. At 1 year, the flap fixation strength in test group 1 (3240 ± 423 N) and test group 2 (3212 ± 662 N) were both statistically greater (p = 0.04 and p = 0.02, respectively) than that in the control group (2418 ± 1463 N); however, there was no statistically significant difference in the strengths when comparing the test groups at both timepoints. Test group 1 had the best overall performance based on histomorphometric evaluation and biomechanical testing. At 2 years postoperatively, the kerfs filled with TTCP-PS had histological evidence of osteoconduction and replacement of TTCP-PS by bone with nearly complete osteointegration.

CONCLUSIONS

TTCP-PS was demonstrated to be safe and effective for cranial flap fixation in an ovine model. In this study, the bioresorbable, osteoconductive bone adhesive appeared to have multiple advantages over standard plate-and-screw bone flap fixation, including biomechanical superiority, more complete and faster bony healing across the flap kerfs without fibrosis, and the minimization of bone flap and/or hardware migration and loosening. These properties of TTCP-PS may improve human cranial bone flap fixation and cranioplasty.

Japanese National Questionnaire Survey in 2018 on Complications Related to Cranial Implants in Neurosurgery

Cranial implants are commonly used throughout the world, yet the data on complications remain partly clarified. The aim of this study was to gather real data in 2018 on complications related to cranial implants in neurosurgery. The survey population consisted of 1103 institutes supplying neurosurgical treatment. The survey consisted of two-stage questionnaire. First the incidence of complications was investigated, then the secondary questionnaire was e-mailed to the respondents about the detailed of the complications. As the result, the annual incidence of complications related to cranial implants was 0.558% in Japan. Titanium plate and mesh were used predominantly in craniotomy and cranioplasty, respectively. The second survey collected data on 449 cases with complications (infection: 63%, implant exposure: 46%, multiple answer). Postoperative infection was associated with male sex, brain tumor, short interval between surgery and complication, usage of ceramics, hydroxyapatite, resin, and artificial dura, hyponutrition, multiple surgeries, dirty wound, and sinusitis as patient factors, and CSF leakage, ruptured sutures, and sinus maltreatment as surgery factors. Meanwhile, long hospital stay was associated with age, male sex, mRS 3–5 before complication, short interval between initial surgery and complication, large craniotomy, long operative time, usage of ceramics and artificial dura, multiple surgeries and dirty wound as patient factors, ruptured suture as a surgical factor, and bacterial infection, especially MRSA infection, as the complication and treatment consisting of removal as complication factors. In conclusion, this is the first Japanese national survey on complications related to cranial implants in neurosurgery. It is important to recall that complications may arise years after surgery and to be aware of the risk factors associated with complications.

Investigation of zinc‑copper alloys as potential materials for craniomaxillofacial osteosynthesis implants

In this study, zinc‑copper (ZnCu) alloys were investigated regarding their feasibility as absorbable metals for osteosynthesis implants, especially in the craniomaxillofacial area. Mechanical properties and in vitro corrosion behavior of as-rolled Zn-xCu (x = 1, 2 and 4 wt%) alloys were systematically evaluated and screened. The as-rolled Zn4Cu alloy had mechanical properties that were superior to the most absorbable craniomaxillofacial osteosynthesis materials recently reported. The addition of Cu to Zn showed to have no apparent effect on the corrosion rates of the samples. The rolling process on Zn and Zn1Cu resulted in more uniform corrosion than on as-cast counterparts after 28 days immersion. Furthermore, the Zn4Cu alloys exhibited no apparent cytotoxic effect towards L929, TAg or Saos-2 cells. Proliferation rates of TAg and Saos-2 cells were shown to be activated by specific Zn ion concentrations in the as-rolled Zn4Cu alloy extracts. Analysis of in vitro antibacterial properties revealed that the as-rolled Zn4Cu alloy possessed the potential to inhibit biofilm formation of mixed oral bacteria. We conclude that the as-rolled Zn4Cu alloy might be a promising material for fabrication of craniomaxillofacial osteosynthesis implants.

Long-Term Safety and Performance of a Polymeric Clamplike Cranial Fixation System

OBJECTIVE

After a craniotomy procedure to access the brain, neurosurgeons have several options to fix the bone flap to the skull. The aim of this study was to assess if a polymeric clamplike fixation system (Cranial LOOP) is a safe and reliable system that maintains over time an appropriate alignment of the bone flap.

METHODS

This is an observational, retrospective, case series study of 60 patients who underwent a craniotomy and were subject to cranial bone flap fixation with the Cranial LOOP fixation system. Baseline clinical parameters, surgical variables, medical records, and all postoperative medical images available were reviewed to assess the bone flap alignment and potential adverse events.

RESULTS

A total of 182 Cranial LOOPs were implanted in the 60 patients (56.01 ± 20.21 years, 55% women) included in the study. The cranial fixation system maintained a good bone flap alignment in 95% of the patients studied immediately after surgery and in up to 96.7% of them at the end of follow-up. No intraoperative complications were reported. An ulcer potentially related to a device was detected, which was solved without the need for device removal. No artifacts were observed in any of the 219 medical images analyzed.

CONCLUSIONS

Cranial LOOP is a safe and reliable postoperative long-term cranial bone flap fixation system. This device can fix the bone flap after a wide range of craniotomy procedures, performed in multiple locations, and provides good bone flap alignment. Cranial LOOP does not interfere in patient follow-up through medical imaging.

Rate of Craniotomy Fusion After Free Bone Flap

BACKGROUND

Craniotomy has been performed in neurologic surgery for over a century. Replacement of free bone flaps in routine craniotomies is widely practiced, however, the rate of fusion after free flap replacement is unknown.

OBJECTIVE

To assess timing and rate of fusion after routine craniotomies.

METHODS

A retrospective cohort study of 2200 patients who underwent craniotomies from 2002 to 2005. Fusion rates and time to fusion were evaluated. When time to fusion was taken into consideration, univariate and multivariate analyses of the impact of clinical factors on fusion rate were also examined.

RESULTS

Of 171 patients with postoperative computed tomography of over 2200 patients undergoing craniotomy, 103 (60%) demonstrated solid fusion, 26 (15%) had probable fusion, and 42 (25%) had not achieved fusion. There were no significant differences when fusion was compared with demographics such as age, sex, body mass index, and history of tobacco use. Radiation therapy had a significant impact on fusion: those receiving radiation were less likely to achieve fusion (P = 0.0082). The fusion rates at 12, 24, and 36 months after surgery were 15%, 41%, and 54%, respectively.

CONCLUSION

As expected, craniotomy fusion rates after free flap replacement increased steadily over time. We were not able to demonstrate that clinical factors such as age, sex, body mass index, diagnosis, fixation material, and radiation had an impact on fusion rate when time to fusion was accounted for. Patients receiving radiation, however, experienced fusion less frequently. Because of the scarcity of previous studies in this area, this current study serves as a platform for future studies on fusion rates after free flap replacement.

Craniotomy bone flap fixation: revisiting the use of bone struts

INTRODUCTION

Bone flap fixation after craniotomy is a standard part of neurosurgical practice. Several techniques and devices exist, though no ideal strategy has been identified. The key aims are to prevent infection and to achieve adequate cosmesis and bony fusion whilst also minimising costs and complications. Ease of use must also be considered. Fixation with sutures and bony struts in the kerf has been described in children and adults and, although the technique achieves many of the ideals of fixation, it does not seem to have been popularised. We report our experience of using the strut technique.

METHODS

A retrospective review of our cranial surgery database, operative notes and follow-up records was conducted. 300 applicable craniotomies were carried out in 8 years. Struts were used in 81 cases and comments on the bony contour described in 21 follow-up records.

RESULTS

In nineteen, the contour was perfect. In one, there was a small bony depression; and in one, there was a small ridge in the posterior part. No repeat operations were carried out for surgery or cosmesis.

CONCLUSIONS

We report our results with a view to reminding the neurosurgical community of the existence of a technique that achieves all the criteria of the ideal fixation strategy.

A Silk Cranial Fixation System for Neurosurgery

Cranial fixation should be safe, reliable, ideally degradable, and produce no hazardous residues and no artifacts on neuroimaging. Protein-based fixation devices offer an exciting opportunity for this application. Here, the preclinical development and in vivo efficacy verification of a silk cranial fixation system in functional models are reported by addressing key challenges toward clinical use. A comprehensive study on this fixation system in rodent and canine animal models for up to 12 months is carried out. The silk fixation system shows a superb performance on the long-term stability of the internal structural support for cranial flap fixation and bone reconnection and has good magnetic resonance imaging compatibility, and tolerability to high dose radiotherapy, underscoring the favorable clinical application of this system for neurosurgery compared to the current gold standard.