A newly designed key-hole button

Long-term follow-up for ossification of autologous bone plug and skin sinking after periosteum-preserved burr hole surgery

Background:

The demand of a burr hole surgery for chronic subdural hematoma (CSDH) is increasing in the global aging society. Burr hole-derived autologous bone dusts are not associated with extra costs compared with other commonly used synthetic materials. In addition, postoperative calvarium ossification requires periosteum-mediated blood supply, which is lacking after using avascular synthetic materials. Based on these findings, we hypothesized that the combination of the bone plugs and the preserved periosteum during burr hole surgeries for CSDH would induce efficient calvarium ossification.

Methods:

We evaluated the long-term effects of bone plugs on the degree of ossification and cosmetic appearance of the skin covering the burr hole sites. We included 8 patients (9 burr holes) who received the autologous bone dust derived from burr holes. As the control group, 9 burr holes that did not receive any burr hole plugs were retrospectively selected. These burr holes were evaluated by computed tomography (CT) scan for the calvarium defect ratios, CT value-based ossification, and the degree of skin sinking.

Results:

Ossification was observed in all the bone plugs by the bone density CT scans; they maintained their volume at 12 months after the surgeries. The calvarium defect ratios (volume ratios of the unossified parts in the burr holes) gradually increased during the first 6 months and reached 0.44 at 12 months. The mean CT values also increased from 527 HU to 750 HU for the first 6 months and reached 905 HU at 12 months. The degrees of skin sinking at the burr hole sites with the bone plugs were 1.24 mm whereas those without the bone plugs were 2.69 mm (P = 0.004).

Conclusion:

Application of burr hole-derived autologous bone dust is associated with better ossification and objective cosmetic result following burr hole surgery after CSDH.

Biodegradable Mineralized Collagen Plug for the Reconstruction of Craniotomy Burr-Holes: A Report of Three Cases

Objectives

In this case report, we describe the design, fabrication and clinical outcomes of a novel bioresorbable, mineralized collagen burr-hole plug for the reconstruction of craniotomy burr-holes.

Methods

Mineralized collagen burr-hole plugs were fabricated via a biomimetic mineralization process. The biomimetic mineralized collagen has a similar chemical composition and microstructure to natural bone tissue, thereby possessing good biocompatibility and osteoconductivity. The mineralized collagen burr-hole plugs were implanted into three patients, and clinical outcomes were evaluated at one-year follow-ups.

Results

All bone defects healed very well using the mineralized collagen burr-hole plugs, and there were no adverse reactions at the surgical sites.

Conclusions

The clinical outcomes indicated that the mineralized collagen was effective for reconstructing burr-holes in the skull after craniotomy.

The Efficacy of Titanium Burr Hole Cover for Reconstruction of Skull Defect after Burr Hole Trephination of Chronic Subdural Hematoma

OBJECTIVE

Although burr hole trephination is a safe and effective surgical option to treat patients with chronic subdural hematoma (CSDH), it often results in a small but undesirable scalp depression from burr hole defect. This study is to evaluate the efficacy of titanium burr hole cover (BHC) for reconstruction of skull defects in these patients.

METHODS

A hundred and ninety-six cases of burr hole trephinations for CSDHs between January 2009 and December 2013 were assigned into two groups; Gelfoam packing only (GPO) and reconstruction using titanium BHC group, according to the modalities of burr hole reconstructions. The incidences and depths of scalp depressions and incidences of postoperative complications such as infections or instrument failures were analyzed in both groups. We also conducted telephone surveys to evaluate the cosmetic and functional outcomes from patient's aspect.

RESULTS

Significantly lower incidence (p<0.0001) and smaller mean depth (p<0.0001) of scalp depressions were observed in BHC than GPO group. No statistical differences were seen in postoperative infection rates (p=0.498) between the two groups. There were no instrument failures in BHC group. According to the telephone surveys, 73.9% of respondents with scalp depressions had cosmetic inferiority complexes and 62.3% experienced functional handicaps during activities of daily life.

CONCLUSION

Titanium BHC is highly effective for reconstruction of skull defect after burr hole trephination of CSDH, and provides excellent cosmetic and functional outcomes without significant complications.

Osteoplastic Pterional Craniotomy Revisited

BACKGROUND:

A standard pterional approach with a free bone flap to treat brain aneurysms was first introduced and popularized by Yaşargil.

OBJECTIVE:

To describe a modified pterional craniotomy technique and that mobilizes part of the sphenoid wing and the pterion in a block with the temporalis muscle to enhance cosmetic results.

METHODS:

A subperiosteal corridor is provided inferiorly by separating the temporalis muscle from the underlying bone in a retrograde dissection. Inferior chisel cuts from the front and back enter the sphenoid wing, enabling removal of part of the sphenoid wing and the pterion in 1 piece, along with the bone flap. Forty patients with aneurysms were treated in this fashion, and the cosmetic outcome was examined at 6 months postoperatively.

RESULTS:

Thirty-seven patients (92.5%) demonstrated an unremarkable degree of temporalis muscle atrophy. Excellent configuration and fusion of the pterional bone flap were observed on 3-dimensional computed tomography scans.

CONCLUSION:

With the use of this muscle-preserving and bone-sparing pterional approach and with little additional labor, temporalis muscle function is preserved and improved cosmesis is obtained.

Comparative study between cortical bone graft versus bone dust for reconstruction of cranial burr holes

Background:

As a consequence of the progressive evolution of neurosurgical techniques, there has been increasing concern with the esthetic aspects of burr holes. Therefore, the objective of this study was to compare the use of cortical bone graft and bone dust for correcting cranial deformities caused by neurosurgical trephines.

Methods:

Twenty-three patients were enrolled for cranial burr hole reconstruction with a 1-year follow-up. A total of 108 burr holes were treated; 36 burr holes were reconstructed with autogenous cortical bone discs (33.3%), and the remaining 72 with autogenous wet bone powder (66.6%). A trephine was specifically designed to produce this coin-shaped bone plug of 14 mm in diameter, which fit perfectly over the burr holes. The reconstructions were studied 12 months after the surgical procedure, using three-dimensional quantitative computed tomography. Additionally, general and plastic surgeons blinded for the study evaluated the cosmetic results of those areas, attributing scores from 0 to 10.

Results:

The mean bone densities were 987.95 ± 186.83 Hounsfield units (HU) for bone fragment and 473.55 ± 220.34 HU for bone dust (P < 0.001); the mean cosmetic scores were 9.5 for bone fragment and 5.7 for bone dust (P < 0.001).

Conclusions:

The use of autologous bone discs showed better results than bone dust for the reconstruction of cranial burr holes because of their lower degree of bone resorption and, consequently, better cosmetic results. The lack of donor site morbidity associated with procedural low cost qualifies the cortical autograft as the first choice for correcting cranial defects created by neurosurgical trephines.

A newly designed hydroxyapatite ceramic burr-hole button

Conventional burr-hole buttons sometimes do not fit the burr hole well due to the curvature of the surrounding bone. An irregular surface at the border between the button and the surrounding skull may appear unaesthetic. The major problem is the difference between the curvature radius of the skull and the burr-hole button in contact with the skull. To solve this problem, the authors designed a button made of hydroxyapatite ceramic to snugly fit the burr hole. The specifications of this device and its clinical application are described here.

Medpor Craniotomy Gap Wedge Designed to Fill Small Bone Defects along Cranial Bone Flap

OBJECTIVE

Medpor porous polyethylene was used to reconstruct small bone defects (gaps and burr holes) along a craniotomy bone flap. The feasibility and cosmetic results were evaluated.

METHODS

Medpor Craniotomy Gap Wedges, V and T, were designed. The V implant is a 10 cm-long wedge strip, the cross section of which is an isosceles triangle with a 4 mm-long base, making it suitable for gaps less than 4 mm after trimming. Meanwhile, the Medpor T wedge includes a 10 mm-wide thin plate on the top surface of the Medpor V Wedge, making it suitable for gaps wider than 4 mm and burr holes. Sixty-eight pterional craniotomies and 39 superciliary approaches were performed using the implants, and the operative results were evaluated with respect to the cosmetic results and pain or tenderness related to the cranial flap.

RESULTS

The small bone defects were eliminated with less than 10 minutes additional operative time. In a physical examination, there were no considerable cosmetic problems regarding to the cranial bone defects, such as a linear depression or dimple in the forehead, anterior temporal hollow, preauricular depression, and parietal burr hole defect. Plus, no patient suffered from any infectious complications.

CONCLUSION

The Medpor Craniotomy Gap Wedge is technically easy to work with for reconstructing small bone defects, such as the bone gaps and burr holes created by a craniotomy, and produces excellent cosmetic results.

Endoscopic cranioplasty with calcium phosphate cement for pterional bone defect after frontotemporal craniotomy: technical note

OBJECTIVE

Postoperative pterional depression is a minor but unpleasant sequela of frontotemporal craniotomy. We developed a simple method for repair of this condition with the use of an endoscope and calcium phosphate cement.

METHODS

The cranial defect was approached by means of endoscopic visualization through a small incision within the hairline. The defect was repaired with an injectable calcium phosphate cement.

RESULTS

The bone defect was easily accessed and readily repaired in all five patients. No adverse reactions to the implant were observed. Satisfactory cosmetic results were obtained in all patients treated with the use of this method.

CONCLUSION

This minimally invasive cranioplasty technique proved to be effective for the repair of the postoperative pterional defect.

Burr hole cover for ventriculoperitoneal shunts and ventriculostomy: technical note

In patients who have undergone intracranial procedures, bone gaps or burr holes often result in small but undesirable scalp or skin depressions. The authors designed a burr hole cover for hydrocephalus shunt system or external ventricular drainage, which is shaped to alleviate the deformity of the burr hole by filling the bone defect and allowing the passage of the ventricular catheter. The specifications of this device and its clinical application are described.