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Chapter 10: Transfrontal Craniotomy 105

Figure 10.16 Dolichocephalic cranium. 1, Junction of nasal bones; 2, zygo­
matic process of the orbit; 3, frontal–parietal sutures; 4, internal table of
frontal bone; 5, cribriform plate.

the necessity of this procedure. Similarly, there are anecdotal
reports of isolating the frontal sinus by packing them with bone Figure 10.17 Repositioning of bone flap, with sutures placed in the
wax or gelatin sponge. After the cavity of the frontal sinus is reached predrilled holes to secure the flap.
the thin bone of the septum of the frontal sinus and the ectoturbi­
nate is gently removed with rongeurs (Figures 10.14, 10.15 and
10.16). Depending on the access desired small Lempert or Kerrison authors recommend watertight dural closure using fascial or syn­
rongeurs can be used. The internal table of the frontal bone overly­ thetic grafts. However, nonclosure of the dura is possible as long as
ing the frontal and olfactory lobes can be removed with rongeurs or precautions are taken to avoid postsurgical infections and pneumo­
high‐speed drill making sure not to damage the meningeal vessels. cephalus. Postoperative antibiotics are often recommended and
The bone in this region is much thinner than any other part of the bacteriological swab culture is suggested to facilitate the choice of
skull. The dorsal sagittal sinus originates from the osseous nasal antibiotic therapy.
septum and the olfactory lobes and transverses caudally in the The bone flap is returned to its original position and fixed with
attached edge of the falx cerebri. It lies ventrally to the sagittal polypropylene sutures or wires. Because wires create MRI and CT
suture and interparietal bone process of the occipital bone. The sag­ artifacts, they should be avoided if further investigations are neces­
ittal sinus collects blood from the dipoic veins (cerebral veins). In sary (Figure 10.17). Once the bone is placed, the fascia and skin are
this region it is not easily identified, although the rostral origin is closed routinely. In cases of craniectomy, the bone defect can be
visible at the level of the projection of the mid portion of the zygo­ closed by simple fascial closure or using polymethylmethacrylate
matic arch [25]. Although rostral damage to the dorsal sagittal sinus (PMMA) at the end of surgery. PMMA has been found to increase
in this area is unlikely to cause problems, it is best avoided. Arteries infection in some human studies, but there are no studies in veteri­
of this region originate mainly from the rostral cerebral arteries; nary neurosurgery and most of the reports are anecdotal. However,
these are end terminal arteries and damage does not cause severe a good seal and aesthetic results are obtained with this approach.
brain necrosis. The advantage of this closure is the opportunity to modify the
Once the dura mater is exposed, this is incised with a #11 scalpel approach by using a high‐speed drill and performing a craniectomy
blade. The dura can be lifted with a nerve hook or blunt dental by extending the bone defect caudally and cranially as necessary,
scraper and the incision continued as desired. The dura is often allowing adaptation to the conformation of the head and increasing
involved in the disease process and large portions will be removed. visualization of the frontal and olfactory lobes. This technique can
Removal of the tumor can be performed via delicate blunt dissec­ also be used in cats.
tion or with the use of an ultrasonic aspirator [15]. Meningiomas
can be highly vascularized and great care should be taken with visu­
alization of the blood vessel associated with the tumor and appro­ Complications
priately cauterized with bipolar cautery. The authors have found it General complications of transfrontal craniotomies are those
useful to cauterize vessels while abundantly irrigating with saline described previously for intracranial surgery: infections at the sur­
and aspiration. This allows visualization of the blood vessel and gical site, increased intracranial pressure, seizures, and pneumonia
makes the bipolar cauterization more effective. In tumors of the [10,11,26]. However, hypertensive pneumocephalus and fistula
olfactory lobe is often difficult to spare the normal tissue and com­ with cerebrospinal fluid (CSF) leakage should be specifically dis­
plete resection of the olfactory bulb can be made without serious cussed when using this surgical approach.
consequences. Different techniques have been suggested for closure Pneumocephalus (asymptomatic intracranial air) after craniectomy
of the dura; however, most of the time this is impossible. Several is a common occurrence in humans. However, the transformation