CHAPTER 184 Endoscopic Treatment of Craniosynostosis

Definitive treatment of infants with craniosynostosis continues to be surgical in nature. The ultimate corrective goal remains achievement of proper cranial and facial anatomic relationships and normalization of overall craniofacial morphology. As described in previous chapters, many procedures have been devised in modern times since Lannalogue introduced strip craniectomies in 1890.¹ These procedures have ranged from simple suturectomies and strip craniectomies^1,2 to very extensive surgical procedures after the development of craniofacial surgery as a distinct surgical discipline in the 1970s.^3–9 Surgical treatment of sagittal synostosis has varied from linear craniectomies to extensive calvarial vault remodeling.^9–15 Management of metopic synostosis has also varied from linear craniectomies to standard bifrontal craniotomies and orbitofrontal advancement and forehead recontouring.^16–26 Likewise, coronal synostosis has been treated with simple suturectomies, unilateral canthal advancements, or bifrontal craniotomies and forehead recontouring.^6,27–43 Finally, lambdoid synostosis is most commonly treated with occipital craniectomies and some sort of occipital reconstructive technique.^44–49

Because of the inconsistent nature of long-term results and the significant trauma associated with these operations, we began to develop and use minimally invasive, endoscopically assisted techniques to treat infants with craniosynostosis more than a decade ago.^{10,15,47–54} The underlying principles of our approach include (1) operating on very young infants (preferably 3 months of age or younger), (2) using the very rapid brain growth that occurs in this age group, (3) allowing brain growth to correct the presurgical deformities, and (4) applying postoperative helmets to aid in and achieve correction and normalization of craniofacial asymmetry. Our original goal was to perform a very simple and rapid operation to halt progressive craniofacial deformation and later perform a definitive procedure on a less severe deformity. However, our early results demonstrated excellent and persistent correction, and thus we began to use these procedures as definitive treatment. Presented in this chapter are the techniques and results of our protocols for treating patients with craniosynostosis by successfully using minimally invasive endoscopic techniques.

Instrumentation

Surgical

Although a comprehensive surgical tray is currently being developed and will soon be available (Karl Storz Endoskope, Tuttlingen, Germany), 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. 184-1). 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 (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, Valley Forge, PA) 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 (Johnson & Johnson, Cincinnati, OH) and liquid thrombin (GenTrac, Inc., Middleton, WI) and Gelfoam (Pfizer, New York). 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 Spine, Raynham, MA) or side-biting rongeurs (Jansen Middleton, C-Med Surgical, Pompton Lakes, NJ) 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, Cincinnati, OH), 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.

FIGURE 184-1 Intraoperative photograph of a patient undergoing endoscopic treatment of sagittal synostosis. A 30-degree endoscope is inserted through the anterior incision and used to visualize the osseous-dura interface. An insulated malleable retractor is placed through the posterior incision to protect the dura during cauterization of the osteotomies.

Helmet

The use of helmets, albeit time- and effort-consuming, plays a critical role in achieving excellent results after the osteotomies and cranial release. Typically, on the third postoperative day the patient’s head is scanned with a proprietary infrared beam Star scanner (Orthomerica Products, Inc., Orlando, FL), and a custom-made helmet is manufactured and delivered on the fifth postoperative day. The helmets are manufactured with the commercially available resin Surlyn (Dupont, Wilmington, DE), which is a thermoplastic ionomer resin and is the random copolymer poly(ethylene-co-methacrylic acid). Its physical properties make it an ideal material for molding cranial helmets. The overall helmet shell is made of Surlyn and the inner padding is made of an ethylene acetate lining and Reston foam stabilizer pads (3M, St. Paul, MN). To standardize the manufacturing process, the patient’s head is scanned locally and the digital data sent to a central manufacturing center (Orlando, FL), where a computer-assisted process allows the creation of a custom-made helmet set to the practitioner’s specifications. The overall goal of the helmets is to assist the brain in reshaping the deformed cranium by allowing cranial expansion in recessed areas and compression in areas of overcompensated growth (Figs. 184-2 and 184-3). 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 between 6 months and 1 year. Parents can be reassured that the prosthetics are well tolerated.

FIGURE 184-2 Cross-sectional diagram of right coronal synostosis after an endoscopic suturectomy is performed. Postoperatively, the helmet is used to place compressive force (red arrows) over the areas of overcompensated growth. Recessed areas are allowed to expand (yellow arrows) to achieve normalization of cranial vault shape.

FIGURE 184-3 Postoperative helmet therapy for sagittal synostosis prevents further anteroposterior elongation (red arrows) while allowing expansion of the temporal and parietal areas (yellow arrows) and normalization of the cephalic index.

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