Cranial plate and screw fixation in infancy: an assessment of risk

[Comparison of polymethyl methacrylate skull implant fixation by three types of titanium fasteners]

OBJECTIVE

To evaluate mechanical strength of three methods of polymethyl methacrylate skull implant fixation in two experimental models.

MATERIAL AND METHODS

The first experiment was performed on a plastic model that was as close as possible to bone in structural characteristics. The second experiment was performed on a biological specimen (a ram's head). We assessed the quality of implant fixation to bone window edges by craniofixes, ties and microscrews and lateral intercortical screws.

RESULTS

Craniofixes are feasible for small flat flaps, but not advisable for wide highly curved implants. They are also the most expensive method of fixation. Implant fixation by ties and microscrews is a universal method comparable in price to craniofix. Lateral intercortical fixation is effective both for small flat implants and wide implants with large curvature. However, this method is not always applicable.

CONCLUSION

Combined fixation by lateral intercortical screws and ties allows for the most effective fixation while reducing the overall price of consumables.

Syndromic Craniosynostosis: Objective and Parent-Reported Outcome Measurements after Cranio-Facial Remodelling Surgeries

INTRODUCTION

Syndromic craniosynostosis (SC) is a rare entity compared to the non-syndromic variant. Treatment involves a multidisciplinary approach towards a multitude of problems. Early intervention is known to be better for optimum results. We reviewed outcomes of children with SC who underwent reconstructive cranio-facial surgery.

MATERIALS AND METHODS

A retrospective study was conducted using data from hospital case files and the picture archival communication system. Objective data like the cephalic index (CI), both preoperatively and post-operatively, were compared. Subjective data for the cosmesis outcome - "Sloan and Whitaker outcome class" - following surgery were assessed. Also, parent-reported outcome measurement (PROM) was performed with various parameters to assess quality of life (QOL).

RESULTS

We had 21 operated cases of SC, with 19 needing cranio-facial remodelling. The male to female ratio was 11:10. Crouzon's syndrome was the most common syndromic association followed by Apert's syndrome. Nineteen patients underwent cranio-facial remodelling surgeries and 2 underwent the ventriculo-peritoneal shunt only - for raised intracranial pressure (ICP). Nine patients underwent cranial remodelling with fronto-orbital advancements, and 3 of these patients also received le-fort's type 3 osteotomy and advancement later. Ten patients underwent fronto-orbital advancement with parieto-occipital barrel-stave osteotomies.

OUTCOMES

Improvement in the CI was maximum at the 6-month follow-up. Six (37.5%) cases had Sloan class 1 outcome, 9 (56.25%) had class 2 outcomes, and 1 patient had a class 6 outcome. Whitaker cosmesis outcomes - 14 out of 16 cases (87.5%) had Category 1 outcomes. PROM was assessed. All parents reported at least a moderate improvement in cosmesis following surgery. Out of 15 cases, 10 (66%) reported significant improvement, while 4 (26.6%) cases reported moderate improvement with respect to eye and visual problems. Four parents reported snoring as a significant problem even after surgery. Most parents felt that the children were doing well, attending regular school, and social well-being was normal and had an overall good QOL.

CONCLUSIONS

SC cases may have a multitude of other problems like raised ICP, ophthalmological problems, poor intelligence, and cognition apart from cosmetic concerns. PROMs revealed good outcomes in terms of cosmesis, cognition, and ophthalmological and oral cavity-related problems. Significant improvement in overall QOL was seen in most patients following cranio-facial remodelling surgery.

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.

Trimming of Absorbable Plates and Screws through Smoothing by Multiple Sonic Activation Procedures Can Increase Local Tissue Reactions in Children with Cranial Fixations

OBJECTIVE

The aim of this paper was to investigate the local reactions due to the melting of absorbable plates and screws after trimming through smoothing by multiple sonic activation procedures (MSAP).

BACKGROUND

Drilling or smoothing by MSAP is performed for the trimming of the absorbable plates and screws for cranial fixation in children. Compared to drilling, smoothing by MSAP is suspected to more commonly cause local tissue reactions; thus, the issue was examined herein.

METHODS

For 90 children with smoothing by MSAP and 83 children with drilling procedures who underwent cranial fixation using absorbable plates and screws, the type, time of onset, and incidence of the local reactions were investigated.

RESULTS

Swelling was the most common reaction, followed by inflammatory reactions with itching, heating, skin-penetrating drainage, and pus formation. The mean time of onset of the local reaction was 10.0 ± 2.3 months after surgery. Local reactions occurred in 30% of the children in the group with smoothing by MSAP, and in 7.2% of the children in the group with drilling, showing a statistically significant difference between the two groups (p < 0.001).

CONCLUSION

It was concluded that drilling rather than smoothing by MSAP to change the shapes of the absorbable plates and screws in cranial fixation can reduce the local reactions.

[Biodegradable fixation systems in pediatric craniofacial surgery: 10-year experience with 324 patients]

INTRODUCTION

Over the past 15 years, resorbable materials have been successfully used for osteosynthesis, but their high cost prevents widespread application. However, the use of resorbable systems could be a method of choice, especially in treatment of children in the active growth period. Obviously, biodegradable materials not only are highly competitive with known metal constructs in terms of fixation rigidity, biocompatibility, and a low risk of infection but also have an undeniable advantage, such as gradual resorption allowing quick return of damaged bones to the physiological conditions of functioning. A special feature of bioresorbable systems is that they can be assembled using ultrasonic welding, which greatly facilitates the fixation process and also provides necessary rigidity, even in cases of joining very thin bones when reliable fixation with screws is impossible.

MATERIAL AND METHODS

Over the past 10 years, we have used biodegradable systems in 324 patients. In 244 of them, we used traditional (plate/screw) systems; in 80 cases, an ultrasonic welding system was chosen for osteosynthesis.

RESULTS

In the present work, we discuss, based on clinical evidence, the advantages and disadvantages of both fixation systems for reconstructive craniofacial surgery in children.

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.

Complications of rigid internal fixation

Over the past 20 years, there have been many advances in the development of bone fixation systems used in the practice of craniomaxillofacial surgery. As surgical practices have evolved, the complications of each technologic advance have changed accordingly. Interfragmentary instability of interosseous wiring has been replaced by the risk of exposure, infection, and palpability of plate and screw fixation systems. The improved rigidity of plate fixation requires anatomic alignment of fracture fragments. Failure to obtain proper alignment has led to the phenomenon known as "open internal fixation" of fracture fragments without proper reduction. The size of the plates has decreased to minimize palpability and exposure. However limitations in their application have been encountered due to the physiologic forces of the muscles of mastication and bone healing. In the pediatric population, the long-standing presence of plates in the cranial vault resulted in reports of transcranial migration and growth restriction. These findings led to the development of resorbable plating systems, which are associated with self-limited plate palpability and soft tissue inflammatory reactions. Any rigid system including these produces growth restriction in varying amounts. In this discussion, we review the reported complication rates of miniplating and microplating systems as well as absorptive plating systems in elective and traumatic craniofacial surgery.

Pediatric craniofacial surgery for craniosynostosis: Our experience and current concepts: Part -1

Craniostenosis is a disease characterized by untimely fusion of cranial sutures resulting in a variety of craniofacial deformities and neurological sequelae due to alteration in cranial volume and restriction of brain growth. This involves vault sutures predominantly, but cranial base is not immune. Association with a variety of syndromes makes the management decision complex. These children need careful evaluation by multiple specialists to have strategic treatment options. Parental counseling is an important and integral part of the treatment. Recent advancements in the surgical techniques and concept of team approach have significantly enhanced the safety and outcome of these children. We had an opportunity of treating 57 children with craniostenosis in the last 15 years at our craniofacial service. Out of them, 40 were nonsyndromic and 17 were syndromic variety. We describe our successful results along with individualized operative technical modifications adopted based on the current understanding of the disease.

Cranial bone fixation: review of the literature and description of a new procedure

OBJECT

Fixation of cranial bone flaps should be reliable, safe, rapid, esthetically acceptable, and inexpensive. It should require minimal foreign material, and ideally it should produce no artifacts on neuroimaging. The authors describe a new procedure that meets these criteria.

METHODS

In this procedure, the cranial bone flap is affixed by tightly packing into the surrounding kerf the shims of bone that are harvested from the under edge of the free bone flap and then securing the flap with absorbable sutures. The result is a keystone arrangement that locks the flap into the craniotomy site.

CONCLUSIONS

The bone shim method for cranial bone fixation was used successfully in 386 of 387 consecutive craniotomies in adults. This procedure for cranial flap fixation is reliable, safe, and rapid, and it achieves solid structural stability with excellent esthetic results. No special tools are required, and, because no plates, screws, or wire are used, all problems associated with these materials are avoided, including the artifacts on postoperative neuroimaging. This method is conceptually simple and quite inexpensive.

Unicoronal suture autotransplantation in the rabbit

INTRODUCTION

Our hypothesis was that a neurocranial suture autograft will, when shielded from dura, grow and be incorporated into the calvarium.

METHODS

Growth was monitored by marker separation in three isohistogenic groups of rabbits, between postnatal days 9 and 90. In order to simulate increased neurocapsular expansion force, the left-sided coronal suture of a group of 20 rabbits was immobilised with a resorbable suture on gestational day 25. The other group of 10 rabbits was sham-operated. On postnatal day 9, 10 of the experimental rabbits underwent transplantation of the suture contralateral to the defect resulting from extirpation of the immobilised suture. The transplant was shielded from dural influence by a platinum foil.

RESULTS

The growth of the immobilised coronal sutures was severely impaired, and also that of the contralateral unicoronal sutures to a lesser extent. A significant catch-up of growth occurred in the transplanted unicoronal sutures. Overgrowth occurred at the donor sites.

CONCLUSION

The results allow us to consider suture transplantation combined with endosteal dura stripping in craniosynostosis surgery.

Intracranial migration of fixation wires following correction of craniosynostosis in an infant

BACKGROUND

In the craniofacial skeleton, osseous fixation techniques for stabilization include stainless steel wire, miniplates or bioresorbable plates; in some cases, stainless steel wires are still indicated. Most recently, several case reports have demonstrated that microplates or stainless steel wires migrate intracranially when used in the craniofacial skeleton in neonates.

PATIENT

We present the case of a 7-year-old male who underwent treatment of brachycephaly at the age of 5 months. In this patient, internal migration of wires was observed.

CONCLUSION

In our opinion, there is a difference between migration of wires and of plates in the growing cranium. Factors affecting the incidence of material migration in cranioplasty are believed to include (1) age, (2) site and (3) the material itself.

Effect of bioabsorbable osseous fixation materials on dura mater and brain tissue

Bioabsorbable materials are frequently used in pediatric cranial surgery, but the effects of these materials on neural tissue are not known. The authors assessed the histologic alterations to dura mater and brain tissue associated with bioabsorbable plates. Fifteen Sprague-Dawley rats were given sham cranial surgery; an additional 30 underwent placement of 8 x 8-mm polylactic acid/poly-glycolic acid plates. The rats were assessed weekly for neurologic or behavioral changes suggesting neural damage. A portion of each group was killed at 3, 6, and 12 months for histologic analysis of cranium, dura mater, and brain tissue by standard hematoxylin and eosin stain. None of the animals showed any behavioral changes or neurologic deficits. The plates were gradually hydrolyzed over the study period, and all had disappeared by 12 months. The histologic examination showed fibrous encapsulation around the plates, accompanied by foreign body giant cell reaction and calcification. Focal gliosis, where evident, was mild and confined primarily to the superficial cortex of the brain beneath the plate. The infiltration of the dura mater and underlying brain parenchyma was negligible. In conclusion, the neurologic and histologic effect of bioabsorbable plates on neural tissue may be considered negligible in the early postoperative period.

Distraction osteogenesis for craniosynostosis

Object

The authors describe the use of distraction devices and surgical techniques of distraction osteogenesis for the treatment of patients with craniosynostosis.

Methods

Since 1994, the authors have performed distraction procedures in 23 patients with craniosynostosis in whom osteogenesis was achieved. Thirteen of the 23 patients underwent a complete Le Fort III midface osteotomy and distraction. In 10 patients the distraction osteogenesis involved the cranial bone; six underwent combined forehead and midface distraction (Le Fort IV distraction) in which multiple internal devices were used after performing a Le Fort IV osteotomy.

An external distraction procedure was used to treat the first two cases. Since 1996, the authors have used internal devices developed in their unit.

Distraction was initiated 1 week after the osteotomy at the rate of 0.5 mm per day for the cranium and 1.0 mm per day for the midface. The consolidation phase after distraction was initiated was 2 to 3 months.

No major complications such as intracranial infection or neurological deficits were observed during the course of distraction osteogenesis. The osteogenesis generated at the distraction site was considerably satisfactory; and recurrence of the deformity in the follow-up period was minimal.

Conclusions

Distraction osteogenesis for craniofacial deformity has numerous advantages: 1) bone grafting is unnecessary; 2) the procedure is less invasive, has short operating time, and less blood loss occurs than in conventional craniofacial procedures; 3) no intracranial dead space is created; 4) there is a good amount of blood flow to the bone segment; and 5) soft-tissue expansion occurs. The authors believe that distraction osteogenesis is a versatile and stable option for the treatment of patients with craniosynostosis.

Biodegradable semirigid plate and miniscrew fixation compared with rigid titanium fixation in experimental calvarial osteotomy

OBJECT

To determine the biocompatibility and suitability of resorbable plates and miniscrews, consolidation of symmetrical, bilateral frontal bone craniotomies that had been closed using various methods was studied in 20 growing lambs.

METHODS

Bone fixation with a flexible, punched polylactide plate and four slowly degradable, self-reinforced poly-levolactide (SR-PLLA) or rapidly degradable, self-reinforced polyglycolide (SR-PGA) miniscrews (10 animals in each group) was compared intraindividually with rigid fixation by using a titanium miniplate and four miniscrews. Plain x-ray films, magnetic resonance images, histological studies, and histomorphometric studies were obtained at 4 to 104 weeks.

CONCLUSIONS

No dislocation, instability, clinical foreign body reactions, infections, or loss of fixation were observed. Bone consolidation of the 2.35-mm-wide craniotomy lines was incomplete; connective tissue-filled defects through the bone were observed in 13 of 28 lines at 26 to 52 weeks. Statistical analyses based on histomorphometric studies showed no difference in consolidation with SR-PLLA miniscrew and titanium plate/screw fixation or between the two resorbable fixation methods. Fixation with rapidly degradable SR-PGA miniscrews resulted in less effective consolidation than on the contralateral titanium-treated side (p<0.05), but the bone segment was thicker (p<0.005). The SR-PGA miniscrews had disappeared by 6 weeks, the polyactide plate by 104 weeks, and the SR-PLLA miniscrews had been mostly resorbed at 104 weeks. Passive translocation of the titanium plates and screws into the bone tissue was seen at 52 and 104 weeks. In rapidly growing lamb frontal bone, comparable consolidation results, without complications, can be achieved with semi-rigid resorbable fixation compared with rigid metallic fixation.