endoscopic treatment of craniosynostosis Flashcards
describe surgical instrumentation for endoscopic craniofacial
A comprehensive surgical tray with custom-designed instruments is available from Storz (Karl Storz Endoskope, Tuttlingen, Germany). We designed and developed the J & B dural retractor, which significantly improves efficiency and safety of the procedure during the osseous coagulation phase. Another key instrument is the endoscopic bipolar forceps, which is extremely useful in the treatment of metopic and coronal synostosis. A specially designed pair of bone cutting scissors is also available from Storz and is particularly useful in older patients, who have thicker skulls. Nevertheless, these procedures can be performed with a relatively simple tray of instruments that are readily available in most operating rooms. The endoscopic equipment consists of two rigid rod-lens endoscopes. A 30-degree angled scope is used to visualize and separate the dura from the overlying stenosed suture and skull. A 0-degree angled endoscope is used to view the dura and bone during coagulation and hemostasis of these two structures (Fig. 195-1). Flexible and fiberoptic scopes are not used because of the lower image resolution that they provide. Standard three-chip cameras and high-definition monitors provide superb visualization of the surgical field. Additional visualization and exposure can be obtained with the use of a rhinoplasty lighted retractor. The retractor connected to a standard light source can be used to elevate the scalp while developing the dissection plane between the galea and pericranium. Bloodless dissection is undertaken with the use of monopolar electrocautery, and the needle tip set at 15 W, blend 1 (Bovie; Valley Lab, Valley Forge, PA). Insulated handheld malleable retractors are used to protect the dura and galea during dissection of the subgaleal plane and coagulation of the diploë after osteotomy and bone resection. To minimize intraoperative and postoperative blood loss from the diploë after the osteotomies are performed, a disposable suction electrocautery handpiece (Valley Lab) is used and set at 60 W. The malleable tip can be adjusted to reach the desired areas for further coagulation, and final hemostasis is achieved with Surgiflo (Ethicon, Somerville, NJ) and liquid thrombin (GenTrac, Middleton, WI) and Gelfoam (Pfizer, New York, NY). In most patients the osteotomies can be made with a pair of sharp curved Mayo scissors, but when the bone is thick (older patients), bone-cutting scissors can be used. When removing the bone in piecemeal fashion (metopic or coronal), curved bone rongeurs (DePuy Synthes Spine, Raynham, MA) can be used to resect the bone near the skull base. When treating a patient with significant trigonocephaly, the sharp bony edges of the osteotomies can be contoured with an electric rasp (Stryker, Kalamazoo, MI). Scalp closure is achieved with 4-0 Monocryl (Ethicon), and Dermabond is used for final skin closure. Of note, no drains are left in place, and Foley catheters, central lines, and arterial lines are not routinely used during any of these procedures.
How do helmets work w craniosynostosis repair? How long do you keep them?
These helmets do not restrict cranial growth but rather redirect it, as evidenced by normal progression of head circumference growth. The younger the child, the more helmets will be worn, with up to three helmets usually required to complete treatment and the duration of treatment ranging from 6 months to 1 year. Parents can be reassured that the prostheses are well tolerated.
Helmets are sometimes used for up to 18 months by patients with sagittal craniosynostosis. The dura in sagittal craniosynostosis is genetically programmed to revert to a scaphocephalic shape during the first year and a half of life. Once the head has normalized, the helmet is used to maintain a normal head shape and counteract the natural tendency toward scaphocephaly. This is why a simple strip craniectomy for this condition has failed historically. With all other sutures, the helmet therapy is stopped with head normalization and does not last 18 months.
describe technique of sagittal synostis repair
Patients are placed in the modified prone position (sphinx) in a viscoelastic pad. Two incisions are made across the midline, each measuring about 3 cm. The first incision is located approximately 2 to 3 cm behind the anterior fontanelle, and the second incision is placed immediately in front of the lambda. The scalp incision is taken through the galea aponeurotica but with preservation of the pericranium. After application of insulated scalp retractors, a needle-tipped monopolar cautery instrument is used to develop the subgaleal plane in a bloodless fashion from the anterior fontanelle to the lambda and about 3 cm from the midline bilaterally. A pediatric craniotome is used to make a bur hole at the edge of each incision. Once the dura is freed from the midline bone with a No. 1 Penfield dissector, a 6-mm osteotomy is made at each incision with 6-mm Kerrison rongeurs. The bone is dissected anteriorly toward the anterior fontanelle and then cut with Mayo scissors in a triangular shape. A 30-degree rigid endoscope is inserted under the bone at the anterior incision and advanced posteriorly toward the lambda with the aid of a 10-French suction tip. Suction is used to dissect, as well as keep the endoscopic field dry and free of blood. A second posterior osteotomy is made at the lambda in similar fashion. Once the dura has been freed from the overlying bone, bone-cutting or Mayo scissors are used to make the lateral osteotomies. Hemostasis is achieved with a large piece of Gelfoam on the dura along with gentle pressure. Wedge (barrel stave) osteotomies are also created with scissors after the dura is freed from the bone directly behind the coronal suture and then directly in front of the lambdoid sutures (Fig. 195-4). Obtaining osseous hemostasis, from the bleeding diploë after the osteotomies, is critical in preventing postoperative hematomas. We have been able to achieve this with the use of the suction-electrocautery unit from Valley Lab. Set at a coagulation level of 60 W, the unit is run along the oozing diploë in a circumferential fashion until all bleeding stops. The wounds are closed with absorbable 4-0 Monocryl sutures and Ethibond. The patient is observed overnight, and pain control is maintained with alternating acetaminophen and ibuprofen and intermittent intravenous morphine as needed. The majority of patients are discharged on the morning after surgery.
technique for coronal endoscopic
Access to the suture is gained through a 2- to 3-cm incision located behind the hairline at the level of the stephanion, and a subgaleal dissection plane is developed between the anterior fontanelle and the squamosal suture (Fig. 195-7). A 7-mm craniotome is used to make a bur hole, which is then enlarged to allow passage of the endoscopes under the bone. Once the dura is safely dissected away from the bone, a 6-mm osteotomy is made with a combination of Mayo scissors and bone rongeurs. The osteotomy extends from the anterior fontanelle to the squamosal suture behind the pterion (Fig. 195-8). Hemostasis is achieved as previously described and the incision closed with Monocryl and Dermabond.
A small 2- to 3-cm incision is made behind the hairline and across the metopic suture. A rhinoplasty lighted retractor is used to develop the subgaleal plane from the anterior fontanelle to the nasofrontal suture. A bur hole is made with a 7-mm craniotome and enlarged with Kerrison rongeurs. A 30-degree endoscope is used to develop a plane of dissection between the dura and the overlying stenosed suture. With scissors and bone rongeurs, a 6-mm osteotomy is made between the anterior fontanelle and the nasion (Fig. 195-11). Bridging veins from the sagittal sinus to the stenosed suture are often encountered and directly cauterized with bipolar forceps. After hemostasis, the incision is closed with Monocryl and Dermabond.
procedure for lamboid synostosis
The patient is placed on a cerebellar horseshoe with the head turned so that the ipsilateral stenosed suture is on the superior horizontal plane. The first incision is made immediately lateral to the lambda on the side of the stenosis, and the second incision is made medial to the asterion. Each incision is about 2 to 3 cm. A rhinoplasty lighted retractor or a 0-degree endoscope can be used to develop the subgaleal plane between the incisions. Two bur holes are made with a pediatric craniotome, each at an incision. The bur holes are enlarged with Kerrison rongeurs. A 30-degree endoscope is then inserted under the bone, along the stenosed suture, to help develop the epidural space. Once freed, the bone can be cut with Mayo or bone-cutting scissors. The osteotomy is about 5 to 8 mm in width (Fig. 195-14). After bone hemostasis is achieved, the skin is closed in a similar fashion as for the other sutures described earlier.
