J Oral Maxillofac
Surg
50:1343-1344,1992
A Lag Screw Technique for Fixation of Cranioplasty Implants RICHARD
H. HAUG, DDS,* AND MATT J. LIKAVEC,
MDt
length 2-mm screws are secured (Fig 2). The soft-tissue 5ap is then replaced and sutured.
This report describes the use of lag screws for fixation of cranioplasty implants. The titanium screws do not interfere with current imaging techniques and allow for the quick removal and reapplication of the implant in the event of reoperation.
Discussion The use of titanium screws has a number of advantages. Titanium is extremely biocompatible, nonallergenic, lightweight, corrosion resistant, and does not interfere with present imaging modalities such as xradiography, magnetic resonance imaging, or computed tomography.‘y2 The use of screws through the outer cortex of the cranium has the advantage of eliminating the subcranial dissection and brain retraction required for traditional wiring or suture techniques. If a second surgical procedure is required, the screws may be removed, the second procedure performed, and the cranioplasty implant and screws replaced. The lag screw method is designed to passively secure the cranioplasty implant and not to compress it as with other traditional lag screw techniques. The purpose of the gliding hole in the cranioplasty implant is to prevent
Technique A subpericranial soft-tissue 5ap is reflected to expose the cranial defect. After isolation of the defect and control of hemorrhage, the cranioplasty implant is fabricated. One premeasured ampule of monomer and one premeasured package of polymer (Cranioplastic, Codman & Shurtleff, Inc, Randolf, MA) is mixed in a stainless steel or glass mixing bowl and then poured into a polyvinyl sleeve. The sleeve is sealed and the mixture is kneaded until doughy. The bag and contents are then placed over the defect and contoured. It is cooled by irrigation and removed when hard. The implant is then taken out of the sleeve, excess material is eliminated, and it is replaced over the defect. A self-limiting drill guide (Synthes Maxillofacial, Paoli, PA) is set to 4 mm for use with the 1.5 mm drill. Four drill holes are then placed equidistantly through the implant flange and then just into the outer table of the cranium. The implant is removed and the thickness of the cranium measured. The drill guide is then set to 4,6, or 8 mm and the cranial drill holes extended to the appropriate depth for the cranium, avoiding perforation of the inner table (Fig 1). The 2-mm drill is then used to widen the cranioplasty implant holes to the same dimension as the outer diameter of the screw. These holes are then countersunk with a no. 10 round bur. The implant is replaced and appropriate
IL
1.5mm Drill
Extended Self Limiting
Received from MetroHealth Medical Center, and the Case Western Reserve University, Cleveland, OH. * Assistant Professor of Surgery. t Assistant Professor of Neurological Surgery. Address correspondence and reprint requests to Dr Haug: Division of Oral and Maxillofacial Surgery, Department of Surgery, MetroHealth Medical Center, 2500 MetroHealth Dr, Cleveland, OH 44109. 0 1992 American Association of Oral and Maxillofacial Surgeons 0278-2391/92/5012-002153.00/O
FIGURE I. Self-limiting drill guide used to extend the cranial bone holes to the appropriate depth.
1343
LAG SCREW TECHNIQUE FOR CRANIOPLASTY
1344
Gliding Hole,
/ 2.0mm Titanium screw
- Cranioplastic
stress fractures that occur in the implant when a positional screw technique or self-tapping screw technique is used. We have used this cranioplasty implant fixation technique in 15 patients without complications or untoward reactions. References
FIGURE 2. Lag screw technique for cranioplasty implant fixation. Note that the screw fits passively into the gliding hole of the cranioplasty implant.
1. Simpson D: Titanium in cranioplasty. J Neurosurg 22:292,1965 2. Malis LI: Titanium mesh and acrylic cranioplasty. Neurosurg 25:35 I, 1989
Surg
50:1343-1344,1992
A Lag Screw Technique for Fixation of Cranioplasty Implants RICHARD
H. HAUG, DDS,* AND MATT J. LIKAVEC,
MDt
length 2-mm screws are secured (Fig 2). The soft-tissue 5ap is then replaced and sutured.
This report describes the use of lag screws for fixation of cranioplasty implants. The titanium screws do not interfere with current imaging techniques and allow for the quick removal and reapplication of the implant in the event of reoperation.
Discussion The use of titanium screws has a number of advantages. Titanium is extremely biocompatible, nonallergenic, lightweight, corrosion resistant, and does not interfere with present imaging modalities such as xradiography, magnetic resonance imaging, or computed tomography.‘y2 The use of screws through the outer cortex of the cranium has the advantage of eliminating the subcranial dissection and brain retraction required for traditional wiring or suture techniques. If a second surgical procedure is required, the screws may be removed, the second procedure performed, and the cranioplasty implant and screws replaced. The lag screw method is designed to passively secure the cranioplasty implant and not to compress it as with other traditional lag screw techniques. The purpose of the gliding hole in the cranioplasty implant is to prevent
Technique A subpericranial soft-tissue 5ap is reflected to expose the cranial defect. After isolation of the defect and control of hemorrhage, the cranioplasty implant is fabricated. One premeasured ampule of monomer and one premeasured package of polymer (Cranioplastic, Codman & Shurtleff, Inc, Randolf, MA) is mixed in a stainless steel or glass mixing bowl and then poured into a polyvinyl sleeve. The sleeve is sealed and the mixture is kneaded until doughy. The bag and contents are then placed over the defect and contoured. It is cooled by irrigation and removed when hard. The implant is then taken out of the sleeve, excess material is eliminated, and it is replaced over the defect. A self-limiting drill guide (Synthes Maxillofacial, Paoli, PA) is set to 4 mm for use with the 1.5 mm drill. Four drill holes are then placed equidistantly through the implant flange and then just into the outer table of the cranium. The implant is removed and the thickness of the cranium measured. The drill guide is then set to 4,6, or 8 mm and the cranial drill holes extended to the appropriate depth for the cranium, avoiding perforation of the inner table (Fig 1). The 2-mm drill is then used to widen the cranioplasty implant holes to the same dimension as the outer diameter of the screw. These holes are then countersunk with a no. 10 round bur. The implant is replaced and appropriate
IL
1.5mm Drill
Extended Self Limiting
Received from MetroHealth Medical Center, and the Case Western Reserve University, Cleveland, OH. * Assistant Professor of Surgery. t Assistant Professor of Neurological Surgery. Address correspondence and reprint requests to Dr Haug: Division of Oral and Maxillofacial Surgery, Department of Surgery, MetroHealth Medical Center, 2500 MetroHealth Dr, Cleveland, OH 44109. 0 1992 American Association of Oral and Maxillofacial Surgeons 0278-2391/92/5012-002153.00/O
FIGURE I. Self-limiting drill guide used to extend the cranial bone holes to the appropriate depth.
1343
LAG SCREW TECHNIQUE FOR CRANIOPLASTY
1344
Gliding Hole,
/ 2.0mm Titanium screw
- Cranioplastic
stress fractures that occur in the implant when a positional screw technique or self-tapping screw technique is used. We have used this cranioplasty implant fixation technique in 15 patients without complications or untoward reactions. References
FIGURE 2. Lag screw technique for cranioplasty implant fixation. Note that the screw fits passively into the gliding hole of the cranioplasty implant.
1. Simpson D: Titanium in cranioplasty. J Neurosurg 22:292,1965 2. Malis LI: Titanium mesh and acrylic cranioplasty. Neurosurg 25:35 I, 1989
