Cranioplasty Using Titanium Mesh After Skull Tumor Resection in Five Dogs

Case report: One-stage craniectomy and cranioplasty digital workflow for three-dimensional printed polyetheretherketone implant for an extensive skull multilobular osteochondosarcoma in a dog

Objective

To report a digital workflow for use and long-term outcome of cranioplasty with a 3D-printed patient-specific Polyetheretherketone (PEEK) implant in a 12-y-old German Shepherd dog after surgical removal of an extensive occipital bone multilobular osteochondrosarcoma (MLO).

Study design

Retrospective case report.

Animal

A 12-year-old neutered female German Shepherd dog was presented with facial deformity, blindness, tetraparesis, and ataxia. Magnetic resonance imaging (MRI) and computed tomography (CT) identified a large skull-based mass extending extra-and intracranially with severe compression of the cerebellum and occipital lobes of the cerebrum.

Methods

One-stage decompressive craniectomy using virtual surgical planned 3D-printed craniotomy cutting guides and the Misonix BoneScalpel® and reconstruction with a patient-specific 3D-printed PEEK cranial implant.

Results

3D-printed craniectomy cutting guides allowed an adequate fit of the cranial implant to the original skull. Misonix BoneScalpel® allowed performing a safe and extensive craniectomy. Postoperative CT (8 weeks after surgery) confirmed the PEEK cranial implant to be in place and without implant rejection. Clinically, the neurological examination identified only a right-hind limb delay in proprioception 8 weeks postoperatively, which remained unchanged at 18 months after surgery. Adjunctive treatment included metronomic chemotherapy. Eighteen months after surgery the dog passed away for reasons unrelated to the MLO, no implant-related complications were reported.

Conclusion

3D-printed craniectomy cutting guides, patient-specific PEEK cranial implant, and metronomic chemotherapy can lead to a successful long-term outcome in dogs with extensive skull MLO.

Clinical significance

PEEK is an alternative biomaterial that can be used successfully for skull reconstruction.

Surgical reconstruction of a composite nasomaxillary and superior labial defect in a dog with a fascia lata graft, titanium mesh implant and angularis oris axial pattern flap

Objective

To document the successful surgical reconstruction of a composite nasomaxillary and superior labial defect using a fascia lata graft, titanium mesh and angularis oris axial pattern flap in a dog.

Case summary

An estimated 2-year-old female intact mixed-breed dog was presented with a composite (hard and soft tissue) nasomaxillary defect, suspected to be caused by a chemical burn. Physical examination revealed nasal discharge, exposed bilateral maxilla and nasal bone, nasomaxillary fistula with air movement, and intrinsic discoloration of the left maxillary canine tooth. The soft tissue lesion extended from the nasal planum rostrally to the medial canthus of the left eye distally and from the right maxillary bone to include a full thickness loss of the left maxillary labium laterally. Computed tomographic images of the head showed chronic osteomyelitis of the maxilla, zygomatic and nasal bones with nasomaxillary fistula and numerous exposed roots of the left maxillary premolars. Staged surgical procedures to address the dentition and nasomaxillary defect were planned. The first procedure consisted of the extraction of periodontally compromised left maxillary premolars, and standard root canal therapy of bilateral maxillary canine teeth. The second procedure consisted of debridement of the non-vital soft and hard tissues and surgical reconstruction of the nasomaxillary defect after virtual surgical planning. Head computed tomography performed 5 months post-operatively revealed a decrease in the size of the osseous defect as well as the resolution of rhinitis.

Clinical relevance

This case demonstrates the feasibility of using a combination of soft tissue graft, titanium mesh, and axial pattern flap in managing nasomaxillary defects. Such defects can lead to chronic rhinitis, infection, discomfort, and long-term morbidity. This case report provides a novel but practical approach for managing defects in the nasomaxillary region in dogs.

Craniectomies for dogs with skull multilobular osteochondrosarcoma using the Misonix bone scalpel: cadaveric evaluation and retrospective case series

OBJECTIVES

To evaluate the Misonix bone scalpel (MBS) for craniotomies in dogs and describe clinical findings and surgical experience in three dogs with large multilobular osteochondrosarcoma (MLO) of the skull.

STUDY DESIGN

Cadaver evaluation and retrospective case series.

ANIMALS

One canine cadaver; three client-owned dogs.

METHODS

Craniotomies of different sizes and at different locations were performed with MBS. Dural tear and bone discoloration were recorded. Clinical, imaging, and surgical findings of dogs diagnosed with MLO and where MBS was used for craniectomies were retrospectively included.

RESULTS

Cadaveric evaluation identified MBS as an efficient tool for rapid craniectomies (> 5minutes) albeit dural tears and some small foci of bone discoloration were observed. Craniectomies could be performed without complications in three dogs with MLO without dural tear or bone discoloration. .Excision was in complete in all cases. The short-term outcome was good, and the long-term outcome was fair to good.

CONCLUSION

Piezoelectric bone surgery with the Misonix bone scalpel is an alternative technology to perform craniectomies in dogs. It was not associated with complications in 3 dogs diagnosed and surgically treated for MLO. Dural tears and suspected bone necrosis can occur. Great care should be taken when using CT to establish disease free surgical osteotomy.

Occipital cranioplasty using customized titanium prosthesis yields successful outcome in association with foramen magnum decompression in dogs suffering by Chiari-like malformation

OBJECTIVE

To describe the use of a customized 3-D-printed titanium prosthesis as adjunctive treatment for foramen magnum decompression (FMD) in dogs with Chiari-like malformation (CM) and syringomyelia (SM).

ANIMALS

8 dogs with clinical signs and MRI findings of CM-SM.

PROCEDURES

3-D reconstruction of CT images of the head was used to simulate an occipital craniectomy and design the prosthesis. FMD was performed, and the prosthesis was implanted. Follow-up was performed 1, 6, and 12 months later, and clinical status was scored. Repeated MRI images were compared to identify changes involving the neural structures, particularly the syrinx.

RESULTS

All prostheses were easily positioned based on the preoperative 3-D models, with no complications. At 12 months after surgery, 3 dogs were free of previous medications, 4 were still receiving steroid medications but at lower doses, and 1 was occasionally receiving acupuncture. MRI of 5 dogs 6 to 20 months after surgery revealed resolution of SM (n = 1), reduced size of SM (3), or worse SM (1). All dogs showed an increase in size of the caudal cranial fossa. Dogs with a longer presurgical duration of the clinical signs and wider syrinx generally had worse outcomes than other dogs.

CLINICAL RELEVANCE

Findings suggested that use of customized 3-D-printed titanium prosthesis and associated FMD can represent an adjunctive option to medically treated dogs with CM-SM. Although the small number of cases precludes definitive conclusions, early surgical treatment, particularly in dogs with a small syrinx, could ensure better long-term outcomes, as previously suggested.

Titanium mesh osteosynthesis for the treatment of severely comminuted maxillofacial fractures in four dogs

INTRODUCTION

Major goals in maxillofacial fracture treatment include to restore the dental occlusion, stabilise the major skeletal supports, restore the contour of the face and achieve proper function and appearance of the face. Titanium is considered an optimal material for maxillofacial reconstruction due to its biocompatibility, high strength, minimal inflammatory reaction and minimal imaging artefact.

OBJECTIVES

To describe the clinical details, surgical technique, pre- and postoperative imaging and short- and long-term follow-up of severely comminuted maxillofacial fractures treated with titanium mesh and titanium screws in dogs.

MATERIALS AND METHODS

Retrospective short case series included four client-owned dogs with maxillofacial fractures. After appropriate medical stabilisation, preoperative CT examination of the head was obtained in all patients for evaluation of fracture configuration and surgical planning. The maxillofacial fractures were stabilised by titanium mesh osteosynthesis. Short- and long-term clinical and radiographic follow-ups were available for all dogs.

RESULTS

Proper dental occlusion and reconstruction of the anatomic buttresses was achieved in all cases. All dogs recovered uneventfully from the surgery and no complications were recorded on the long-term follow-up up to 43 months. Occlusion was maintained in all dogs, as well as excellent cosmesis of the midface.

CLINICAL SIGNIFICANCE

Titanium mesh osteosynthesis can achieve sufficient rigidity and lead to uncomplicated healing of severely comminuted maxillofacial fractures. This internal fixation method can be considered a valuable option to treat maxillofacial fractures in particular in cases of large bone defect and midface reconstruction.

Formation of a meningoencephalocele after removal of a frontal lobe meningioma by transfrontal craniotomy in a cat

Case summary

A 10-year-old castrated male domestic shorthair cat was referred for surgical treatment of a left-sided frontal lobe meningioma diagnosed by CT. Clinically, the cat had generalised tonic–clonic seizures, which reduced in frequency after treatment was started with prednisolone. After definition of the anatomical landmarks of the feline skull, a bilateral transfrontal craniotomy allowed en bloc removal of the meningioma. While postoperative recovery was uneventful, right-sided proprioceptive deficits were still present 6 months after surgery. MRI detected a probable meningoencephalocele herniating through the surgical bone defect in the frontal sinus. Because of the mild neurological deficits and good quality of life, the meningoencephalocele was not treated. Thirty-one months after meningioma removal the cat was alive without further neurological progression.

Relevance and novel information

To our knowledge, this is the first report to describe, in detail, the technique of transfrontal craniotomy in cats. Iatrogenic meningoencephalocele is a complication that has not previously been described after meningioma removal in cats, and should be considered as a potential complication after craniotomy.

Schedule feasibility and workflow for additive manufacturing of titanium plates for ranioplasty in canine skull tumors

Background

Additive manufacturing has allowed for the creation of a patient-specific custom solution that can resolve many of the limitations previously reported for canine cranioplasty. The purpose of this pilot study was to determine the schedule feasibility and workflow in manufacturing patient-specific titanium implants for canines undergoing cranioplasty immediately following craniectomy.

Results

Computed tomography scans from patients with tumors of the skull were considered and 3 cases were selected. Images were imported into a DICOM image processing software and tumor margins were determined based on agreement between a board-certified veterinary radiologist and veterinary surgical oncologist. Virtual surgical planning was performed and a bone safety margin was selected. A defect was created to simulate the planned intraoperative defect. Stereolithography format files of the skulls were then imported into a plate design software. In collaboration with a medical solution centre, a custom titanium plate was designed with the input of an applications engineer and veterinary surgery oncologist. Plates were printed in titanium and post-processed at the solution centre. Total planning time was approximately 2 h with a manufacturing time of 2 weeks.

Conclusions

Based on the findings of this study, with access to an advanced 3D metal printing medical solution centre that can provide advanced software and printing, patient-specific additive manufactured titanium implants can be planned, created, processed, shipped and sterilized for patient use within a 3-week turnaround.

Single-Stage Craniectomy and Cranioplasty for Multilobular Osteochondrosarcoma Managed with a Custom Additive Manufactured Titanium Plate in a Dog

A 9-year-old spayed female dachshund presented with a large multilobular osteochondrosarcoma of the crania, with obliteration of approximately 70% of the surface area of the dorsal calvaria and intracranial extension. The mass was excised with histologically clean lateral bone margins (2-4 mm) and invasion at the deep margin. The resulting defect was reconstructed with a custom titanium plate. The patient recovered routinely and was asymptomatic until 7 months postoperatively. The patient developed intractable seizures 7 months postoperatively and was euthanized. Post-mortem examination showed tumor regrowth within the brain parenchyma. No abnormalities were seen associated with the plate. The patient-specific, custom additive manufactured titanium plate provided an excellent option for anatomic reconstruction and protection of the brain over a relatively large area with no complications noted.

Prolonged survival after craniectomy with skull reconstruction and adjuvant definitive radiation therapy in three dogs with multilobular osteochondrosarcoma

Multilobular osteochondrosarcoma is an uncommon canine tumor but presents a treatment challenge when arising on the skull. This retrospective case series study aimed to describe outcome of a multimodality treatment approach involving aggressive surgical resection and adjuvant definitive radiation therapy in a group of dogs with multilobular osteochondrosarcoma of the calvarium. Clinical, imaging, treatment, and outcome data were collected from retrospective review of medical records. Three dogs met inclusion criteria. The presenting clinical complaint was the presence of a mass effect of the skull in all three dogs and concurrent neurologic abnormalities in one dog. Advanced imaging revealed aggressive lytic and proliferative tumors arising from the calvarium in all three dogs. All dogs were treated surgically with a modified craniectomy, repaired with a titanium mesh-polymethyl methacrylate bone cement implant or a low prolife titanium mesh plate and followed by adjuvant definitive radiation therapy with 2.5 Gy per fraction for 22 daily fractions. There were no major immediate surgical complications and radiation was well tolerated overall. Neurologic improvement was seen in the patient that presented with neurologic disease. Survival times from surgery were 387, 422, and 730 days and from the time of radiation were 358, 397, and 677 days. Findings in this sample of three dogs supported the use of aggressive therapy with a combination of surgical craniectomy and cranioplasty utilizing a titanium mesh implant and high dose definitive radiation therapy for local control and prolonged survival times in dogs with multilobular osteochondrosarcoma of the skull.

Treatment of calvarial defects by resorbable and non-resorbable sonic activated polymer pins and mouldable titanium mesh in two dogs: a case report

BACKGROUND

To date, calvarial defects in dogs have traditionally been addressed with different types of implants including bone allograft, polymethylmethacrylate and titanium mesh secured with conventional metallic fixation methods. This report describes the use of an absorbable and non absorbable novel polymer fixation method, Bonewelding® technology, in combination with titanium mesh for the repair of calvarial defects in two dogs. The clinical outcomes and comparative complication using resorbable and non-resorbable thermoplastic pins were compared.

CASE PRESENTATION

This report of two cases documents the repair of a traumatic calvarial fracture in an adult male Greyhound and a cranioplasty following frontal bone tumor resection in an adult female Cavalier King Charles Spaniel with the use of a commercially available titanium mesh secured with an innovative thermoplastic polymer screw system (Bonewelding®). The treatment combination aimed to restore cranial structure, sinus integrity and cosmetic appearance. A mouldable titanium mesh was cut to fit the bone defect of the frontal bone and secured with either resorbable or non-resorbable polymer pins using Bonewelding® technology. Gentamycin-impregnated collagen sponge was used intraoperatively to assist with sealing of the frontal sinuses. Calvarial fracture and post-operative implant positioning were advised using computed tomography. A satisfactory restoration of skull integrity and cosmetic result was achieved, and long term clinical outcome was deemed clinically adequate with good patient quality of life. Postoperative complications including rostral mesh uplift with minor associated clinical signs were encountered when resorbable pins were used. No postoperative complications were experienced in non-resorbable pins at 7 months follow-up, by contrast mesh uplift was noted 3 weeks post-procedure in the case treated using absorbable pins.

CONCLUSIONS

The report demonstrates the innovative use of sonic-activated polymer pins (Bonewelding® technology) alongside titanium mesh is a suitable alternative technique for skull defect repair in dogs. The use of Bonewelding® may offer advantages in reduction of surgical time. Further, ultrasonic pin application may be less invasive than alternative metallic fixation and potentially reduces bone trauma. Polymer systems may offer enhanced mesh-bone integration when compared to traditional metallic implants. The use of polymer pins demonstrates initial potential as a fixation method in cranioplasty. Initial findings in a single case comparison indicate a possible advantage in the use of non-absorbable over the absorbable systems to circumvent complications associated with variable polymer degradation, further long term studies with higher patient numbers are required before reliable conclusions can be made.