Lambdoid Synostosis

Operative Planning

Physical exam
- Distinguish lambdoid synostosis from positional plagiocephaly
- Lambdoid synostosis
  - Rare, prevalence is ~0.3:10,000
  - Ipsilateral ear posterior displacement
  - Ipsilateral occipitomastoid bulge or prominence
  - Contralateral frontal retrusion
  - Ridging along the lambdoid
  - No history of positioning on one side
  - No history of torticollis
- Closed fontanelle does not indicate lambdoid synostosis (or any craniosynostosis). Craniosynostosis is a problem of the sutures, not the fontanelles.
Review imaging
- Three-dimensional computed tomography scan
  - Look for fused suture; plain films are not helpful in ruling in or ruling out synostosis
  - Endocranial view: cranial base is rotated to side of plagiocephaly from lambdoid synostosis. In positional plagiocephaly, the posterior cranial base remains in line with the anterior cranial base midline.
Reconstructive procedure, discuss risk/benefit with family
Ophthalmologic consult to rule out papilledema, especially if family elects not to perform surgery. If papilledema is present no longer only reconstructive.
Plastic surgery consult, combined procedure
Discuss timing of surgery (8 to 10 months old)
Discuss donor-directed blood

Special Equipment

Handheld Hudson brace or perforator with pediatric burr
0 Prolene sutures
Resorbable plates and screws
Local anesthetic (bupivacaine 0.25% with 1:200,000 epinephrine; 1 mL/kg is maximum dose)

Intravenous (IV) antibiotics (cefazolin 25 mg/kg/dose)
Foley catheter
Arterial line
Begin blood transfusion at skin incision. Typically three units of packed red blood cells are reserved: donor-directed or banked autologous.

Positioning

Patient prone
Patient’s head is positioned on the bed in a neutral position (cerebellar head frame)
Minimal reverse Trendelenburg
Total shave
- Hair clippers (hair is saved and given to the parents if first haircut)

Sterile Scrub and Prep

Clean incision line and surrounding area with 70% ethanol followed by a prescrub with scrub brush followed by a two-step Betadine preparation, first with Betadine soap followed by Betadine scrub.

Incision and Exposure

Plastic Surgery

Bicoronal incision with elevation of posterior scalp flap
Wide exposure of basicranium
Osteotomy of basicranium; repositioning of basicranium on affected side (retropositioned to lie symmetric with normal side)
Craniotomy (see Neurosurgery next) with generation of two occipitoparietal bone flaps
“Switch” cranioplasty with replacement of one bone flap for the other, with rotation 90 to 180 degrees until optimal posterior vault contour is achieved
Resorbable or wire fixation for bone stabilization

Neurosurgery

Bilateral bur holes at the asterion
Two burr holes in the midline: one over the sagittal sinus, the other in the midline at the inferior extent of the exposed bone per plastic surgery. This burr hole is safely below the torcula, but the keel can sometimes be quite deep and care needs to be given to protect the dura. The authors prefer the handheld Hudson brace for these burr holes.

Free the dura from the inner table with a Penfield no. 3. If the dura is tenaciously adhered to the inner table, place more burr holes around the perimeter of the bone flap and/or along the midline. When freeing the underlying dura be careful not to injure the transverse or sagittal sinuses.
If in doubt, place more burr holes; the parietoccipital flap does not have to come off in one large piece, it can be in two, because the plastic surgeons will cut it in two for the “switch” cranioplasty.
Prior to using the craniotome, use the Bovie to remove the pericranium from the skull along the path of the craniotome to prevent the soft tissue from being taken up by the craniotome.
Carefully elevate the skull using a Cobb periosteal.
Quickly identify dural bleeders and use the bipolar to coagulate them.
Look for dural lacerations. If encountered, primarily repair them with 4–0 Nurolon sutures.
Achieve meticulous hemostasis and carefully survey for cerebrospinal fluid (CSF) leaks.
Turn case back over to the plastic surgeons for closure.

Complications

Blood loss

Avoidance: excellent IV access, begin transfusion at skin incision, careful dissection of dura from the bone flap, especially over the sagittal and transverse sinuses, and frequent communication between the surgeons and the anesthesiologist
Intervention: meticulous hemostasis at each operative step and rapidly infuse blood and clotting factors, and have a low threshold to abort the procedure before onset of disseminated intravascular coagulation

Dural tear

Avoidance: careful placement of burr hole and freeing of the dura at the keel; may require burr holes on each side and careful bone removal with a Kerrison punch
Intervention: repair primarily with 4–0 Nurolon or patch with a piece of pericranium

CSF leak

Avoidance: careful elevation of the skull flap
Intervention: repair primarily with 4–0 Nurolon; rarely requires placement of a lumbar drain or serial lumbar punctures