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231
Limitations
Exposure anterior to the pituitary and posterior to the carotid artery is not possible with
this approach.
Complication
The risk of devascularization of the alveolar
ridge leading to palatal necrosis is a potential
complication.
3. Transpalatal Approach
This is another midline approach with the following variants:
• Palatal Retraction—Retracting the soft
palate anteriorly provides exposure for
adenoidectomy, biopsy and excision of
small tumours from the nasopharynx.
• Palatal Split—Vertical division of the soft
palate allows exposure from the lower
third of clivus to C2. Can be used for basilar artery aneurysm.
• Palatal Drop—Owen’s inverted U inci-
sion is placed on the palate about 1 cm
medial to the alveolar ridge, separating the
hard and soft palate for choanal atresia and
angiobroma.
• Sardana’s Approach—S-shaped incision
with three segments, a peroral palatal drop
approach (Owen’s incision), an ipsilateral
sublabial incision and a connecting
U-shaped incision curving behind the maxillary tuberosity and connecting the previous two incisions. Especially indicated for
tumours extending from the nasopharynx
to the infratemporal fossa via the pterygomaxillary ssure.
Limitation
The transpalatal approach and its modication
allow excision of midline tumours from the
nasopharynx to C2. Exposure anterior to choana and sphenoid sinus, lateral to Eustachian
tube and posterior to foramen magnum and
brainstem are not accessible.
Complication
Palatal stula is a potential complication.
4. Denker’s Approach
Trans-naso-maxillary approach—Involves a
large Caldwell–Luc antrostomy through sublabial route followed by removal of lateral
nasal wall and frontal process of maxilla.
Essentially a medial maxillectomy is undertaken via the sublabial route.
5. Preauricular Subtemporal Approach ((Fig.
6.17, Chap. 6), Figs. 7.13 and 7.26)
Unlike maxillary swing which provides a
direct anterior approach to the infratemporal
fossa, preauricular subtemporal offers a lateral approach to the same. It is indicated in
case of tumour involvement lateral and posterior to cavernous part of ICA. One can
approach the entire skull base from the nasopharynx to the petrous apex and clivus with
minimal brain retraction.
6. Facial Translocation Approach
This approach is based on the concept of
“Modular-Disassembly” of facial subunits by
Janecka etal. [45]. This means that the face is
divided into subunits each with its own neurovascular supply. It is divided into:
(a) Limited facial translocation
(b) Standard facial translocation
(c) Extended facial translocation
An example of standard facial translocation is
provided here. To approach the nasopharynx
as well as infratemporal fossa and middle cranial fossa, the entire maxilla, lateral orbital
wall and zygoma can be swung laterally as
one single unit.
7. Maxillectomy
Maxillectomy can be classied as either total
if all six walls are removed or partial if it
involves preservation of any of the six walls.
Examples of partial maxillectomy include:
medial maxillectomy, subtotal maxillectomy
(preserving orbital oor) and palate preserving maxillectomy. Sometimes orbital exenteration is performed along with total
maxillectomy. In this case, the appropriate
term would be a radical maxillectomy.
(a) Total maxillectomy (Fig.7.27)
Indicated in malignancy arising from the
maxillary sinus, invasive fungal disease
causing destruction of the maxillary
sinus. The soft tissue approach preceding
a maxillectomy can either be a Weber–
Ferguson incision or a sublabial incision.
It involves excision of the maxillary
sinus, one half of the hard palate, oor of
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the orbit, palatine bone, lateral wall of
nose and the inferior turbinate. The following osteotomies are performed to
mobilize the maxilla:
(i) Superomedially—Nasal process of
maxilla.
(ii) Superolaterally—Between maxilla
and zygomatic arch.
(iii) Inferiorly—Between lateral incisor
and canine till midline of palate.
Fig. 7.26 Left side marked Preauricular Subtemporal
Approach
(iv) Inferolaterally—The maxilla is sep-
arated from the pterygoid plates.
• May be accompanied by ethmoidectomy or sphenoidotomy
(b) Partial Maxillectomy: Medial maxillec-
tomy: with or without ethmoidectomy.
Involves resection of medial wall of maxillary sinus from the oor of orbit to oor
of nasal cavity. The most common nasal
pathology where this is indicated is
inverted papilloma.
Osteotomies:
(i) Supromedially—From pyriform
aperture towards inferior orbital ssure, inferiorly and parallel to
fronto-ethmoidal suture line
(ii) Laterally—Vertically along anterior
wall of maxilla towards inferior
orbital ssure along oor of orbit
(iii) Inferiorly—Above the alveolar arch
(iv) Infero-medially—Parallel to oor of
nasal cavity oor inferior to inferior
turbinate
8. Craniofacial Resection (Fig. 7.28)
Involves resection of intracranial as well as
extra-cranial parts of a sinonasal tumour
extending to the anterior skull base. Paranasal
sinuses are approached either by a lateral rhi-
Fig. 7.27 Maxillectomy specimen. Cuts are made the same as maxillary swing but anterior soft tissue ap is separated
from underlying bone as showed in Fig. 6.16 of Chap. 6.
ab
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Fig. 7.28 Craniofacial resection
233
notomy or a midfacial degloving. Tumour
may also be approached by a nasal endoscopic
approach. For the purpose of anterior skull
base exposure, a bifrontal craniotomy is performed using a bicoronal incision. Cheesman
and Reddy [46] have classied craniofacial
resection into three types:
• Type I: It is an extended medial maxillectomy with limited resection of the anterior
part of the skull base without resorting to a
craniotomy.
• Type II: Here the intracranial component is
approached through a window craniotomy.
• Type III: This is the traditional craniofacial
resection where bicoronal incision is made
followed by bifrontal craniotomy.
9. Transbasal Approach
The difculties and potential complications
related to a craniofacial resection are mitigated to a certain extent by the transbasal
approach. The soft tissue approach can be
either a bicoronal incision or a brow incision
or a spectacle incision. Instead of performing
a bifrontal craniotomy, the frontonasal unit is
elevated as a free bone ap. The advantages in
doing so are limited brain retraction while
approaching lesions, extending posteriorly
towards the clivus. If approached through traditional craniofacial resection, the resulting
brain retraction produces signicant perioperative morbidity.
7.5 Part E: Open Anterior Skull
Base Approaches:
Indications
andComplications
The anterior cranial base has an endocranial surface,
which faces the brain, and an exocranial surface,
which faces the nasal cavity and sinuses, orbits,
pharynx, infratemporal and pterygopalatine fossae,
and the parapharyngeal and infrapetrosal spaces.
Canals, foramina and ssures through which numerous neural and vascular structures passes connect
both the surfaces. On the endocranial side, the border between the anterior and middle cranial bases is
the sphenoid ridge joined medially by the chiasmatic
sulcus. On the exocranium side, the anterior and
middle cranial bases are divided at the level of a
transverse line extending through the pterygomaxillary ssures and the pterygopalatine fossae at the
upper level and the posterior edge of the alveolar
process of the maxilla at a lower level. Medially, this
corresponds to the anterior part of the attachment of
the vomer to the sphenoid bone.
The pathological conditions affecting the
anterior cranial base are highly heterogeneous
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groups. They can be classied according to the
site of tumour origin as described below:
1. Basal neurovascular structures and
meninges
• Meningiomas: Olfactory groove, Planum
Sphenoidale, Tuberculum sella
• Schwannomas
• Pituitary adenoma
• Craniopharyngiomas
• Paraganglioma
• Hemangiopericytoma
2. Cranial base
• Chordoma
• Chondrosarcoma
• Osteosarcoma
• Plasmacytoma
• Metastasis
3. Subcranial with upward extension
• Sinonasal carcinomas
• Olfactory neuroblastoma
• Juvenile angiobroma
• Nasopharyngeal carcinoma
• Adenoid cystic carcinoma
• Primary sarcomas
Anosmia, frontal lobe dysfunction, increased
intracranial pressure, nasal obstruction, CSF rhinorrhoea, epistaxis, visual changes and endocrine
dysfunction are the list of symptoms with intracranial connection of mass lesion of the nose and
paranasal sinuses.
7.5.1 Diagnostic Work-Up
The clinical examination is focused on complete
evaluation with special attention to the head and
neck region. Supplemental information regarding
the extent of the tumour can be obtained by ophthalmoscopy, indirect laryngoscopy or exible
breoptic nasopharyngoscopy. The imaging battery includes contrast-enhancing computerized
tomography (CECT) scan, magnetic resonance
imaging (MRI) with contrast scan. The diagnostic
cerebral angiography (DSA) is indicated in
selected cases to obtain information regarding vascularity of the lesion and possible involvement of
surrounding major neurovascular bundle. Elective
preoperative angiographic embolization is advised
in highly vascular cases to reduce intraoperative
blood loss. Quantitative assessment of visual acuity and visual eld charting is required to document the preoperative status of vision. Endocrine
work-up is for tumours extending to the sellar/
suprasellar region. The approaches for anterior
skull base are tabulated in Fig.7.29 [47, 48].
Transcranial approaches indicated for lesions
restricted to the intracranial compartment. They
are divided into anterior and anterolateral
approaches depending upon the tumour extensions [49–51]:
1. Anterior:
• Bifrontal craniotomy
• Unifrontal craniotomy
• Transbasal craniotomy
Anterior craniotomy approaches are indi-
cated for midline lesions like meningiomas of
olfactory groove, planum sphenoidale, tuberculum sella, esthesioneuroblastomas without lateral extensions. Large midline lesions are
approached using bifrontal craniotomy whereas
small lesions can be approached using either
unifrontal/bifrontal craniotomy. The incision is
bicoronal or unilateral frontal curvilinear incision. Following the incision, a bifrontal (large
lesions) or unifrontal (small lesions) craniotomy
is performed. Dura is opened based on superior
sagittal sinus (SSS) and the sinus ligated and
cut. Sinus ligation is done in large lesions
involving the cribriform plate. Smaller lesions
may not require sinus ligation (Fig.
2. Anterolateral—Five types of anterolateral
approaches are described:
(a) Fronto-orbital
(b) Fronto-temporal craniotomy
(c) Pterional craniotomy (Frontosphe notemporal)
7.30).
Approaches
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Transfacial
Subcranial
235
• Lateral rhinotomy
• Weber-Ferguson
• Lynch incision
• Dieffenbach incision
• Subciliary/Midcilary
• Midfacial degloving
(MFD)
Craniofacial
Transcranial
to Anterior
Skull Base
Lesions
Combined
Approaches
Fig. 7.29 Approaches to anterior skull base
Bifrontal craniotomy with subfrontal approach
• Unilateral frontal craniotomy with subfrontal
approach
• Pterionalapproach
• Fronto-orbital approach
• Frontotemporal-orbitozygomatic (FTOZ)
approach
Subcranialor craniofacial with ipsilateral /bilateral partial
maxillectomy (Extension to Medial or superior maxillary walls
and periorbita)
• Subcranial–MFD (Benign tumours extending to the maxillary
sinus compartment ±Pterygopalatine fossa or nasopharynx)
• Craniofacial with Weber-Fergusson incision (Malignant
tumours extending to the inferior/ anterior/lateral/posterior
maxillary walls)
• Subcranialor craniofacial with pterional (Extension to the
lateral skull base, cavernous sinus, middle fossa or
Infratemporal fossa)
• Subcranial-LeFortI (Extension to the lower clival region)
• Subcranialor transcranial with transorbital (Orbital apex or
intraorbitalextension)
• Transcranial-transfacial-transorbital (for Malignant tumours
extending to the maxillary sinus with intra-orbital extension)
(d) Fronto-temporo-orbito-zygomatic
(FTOZ): An extension of pterional
craniotomy
(e) Supraorbital keyhole craniotomy
Fronto-orbital is useful for lesions with orbital
extensions. Fronto-temporal craniotomy is
used for lesions with lateral and middle cranial fossa extensions. Pterional craniotomy is
the workhorse of neurosurgery as most of the
lesions can be approached with this
craniotomy.
It is for midline lesions of anterior as well as
middle fossa lesions like meningiomas, sellar/
suprasellar and para-sellar lesions. FTOZ is an
extension of the pterional craniotomy with
additional removal of orbit and zygomatic
bones (Fig. 7.31). FTOZ is useful for lesions
involving cavernous sinus and suprasellar
lesions reaching up to the third ventricle.
Supraorbital keyhole is the mini frontolateral craniotomy (Fig.7.32). It starts with an
eyebrow incision and it is cosmetically acceptable, includes frontal-orbital and part of the
zygomatic process. The indications are anterior skull base lesions, sellar suprasellar
lesions and aneurysms of anterior circulation.
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ab
c
Fig. 7.30 Stepwise demonstration of transbasal
approach: (a) Bicoronal skin incision and elevation of
subgaleal ap separately for skull base carpeting later, (b)
Burr holes on either side of SSS, (c) Single-piece crani-
It is contraindicated in well-pneumatized
frontal sinus and lesions involving cribriform
plate (relative contraindication).
7.5.2 The Subcranial Approach
It is a single-stage procedure used for tumours
involving the anterior skull base [52, 53]. It
involves coronal incision and osteotomy of the
naso-fronto-orbital bone segment. It allows
access to the intra- and extra-cranial compartments of the anterior skull base. The advantages
d
otomy with intact bilateral superior orbital walls and
nasion, (d) Exposed bifrontal dura, spatula in midline
over SSS, bilateral orbit (Star), bilateral frontal sinus and
ethmoids (Donut) along with nasion
are direct exposure of the anterior skull base from
anterior to posterior, allows simultaneous intradural and extradural tumour removal from anterior to posterior, does not require facial incisions
and minimal frontal lobe manipulation. The disadvantage of this approach is osteonecrosis,
especially following radiotherapy (RT).
7.5.3 Reconstruction
The aim is to create watertight dural closure and
secure barrier between the nasal cavity and the
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237
Fig. 7.31 Stepwise demonstration of FTOZ craniotomy.
(a) Positioning with malar eminence as the highest point,
(b) Curvilinear hairline incision, (c) Fronto-temporo
zygomatic bony exposure with cuff of muscle left attached
along the superior temporal line, (d) Single-piece craniotomy with the temporalis muscle cuff, (e) Exposed orbit
(Star) and the fronto-temporal dura, (f) Bone xed with
miniplates and screws
Fig. 7.32 (a) Eyebrow incision shown as red, (b) eleva-
tion of periosteal ap (star) separately, suction pointing on
the supraorbital frontal bone, (c) fashioning the craniotomy (2.5 × 2.5 cms) using the footplate drill, (d) exposed
dura, (E) after dural opening using suction and scissors
and suction as dynamic retractors resting on the basifrontal lobe covered with cotton (star) and basal dura of anterior cranial base (yellow asterisk)
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cranial cavity. It can be done by curetting of
mucosa of frontal, ethmoidal and sphenoidal
sinus and packed with fat. The dura defects
should be closed primarily with sutures or with a
fascial graft. Basal repair performed by placing a
pedicled galea aponeurotica-pericranial-frontalis
muscle ap based on the supraorbital–supratrochlear vessels along the anterior cranial fossa
base (Fig. 7.28a). Further posterior reinforcement of fascia lata graft with temporalis muscle
rotation is required to obliterate the dead space.
Bony segments secured in their respective anatomical positions using sutures or miniplates +
autologous temporal or frontal bone to reinforce
the skull base bony reconstruction. Additionally,
musculocutaneous and free aps based on the
pectoralis major and trapezius as well as free
omental aps for basal repair.
7.5.4 Complications
Transcranial surgery has a long list of complications
such as cerebral edema, frontal lobe signs (mainly
due to retraction)—decits of speech, memory,
cognitive and intellectual function, seizures, CSF
leak, subdural or extradural haematoma, pneumocephalus, CNS Infections like meningitis and brain
abscess, vascular complications like carotid, anterior/middle cerebral artery injuries, hormonal dysfunction and cranial nerve decits [54].
7.6 Part F: Lacrimal Sac Anatomy
andDCR
The lacrimal gland has a tubule-acinar structure
and secretes serous tears in superior fornix. The
secretomotor bres are from the VII nerve
through the pterygopalatine ganglion. The lacrimal system starts from the lacrimal puncta
and consists of vertical and horizontal canaliculi (upper and lower), a common canaliculus,
lacrimal sac and nasolacrimal duct. Lacrimal
sac is 12–15mm long, situated in lacrimal fossa
formed by frontal process of maxilla and lacrimal bone, anterior to posterior. The superior
border of the lacrimal sac is above the middle
turbinate’s anterior attachment and is lateral to
the agger nasi cells. The anterior attachment of
the uncinate process is regarded as the posterior
limit of bone removal. The lacrimal sac and
nasolacrimal duct slopes down backward and
inward. Chronic dacryocystitis is more common in females than males because of the narrow nasolacrimal duct in women. On blinking
the orbicularis muscle alternate contraction and
relaxation creates negative pressure in the lacrimal sac; this tear pump helps in sucking tears
into the sac. Capillary action carries most of the
tears (70%) into the lower punctum and canaliculus, while the rest is carried through the
upper punctum and canaliculus.
As demonstrated on Scintillography, the transfer of uid from the canaliculi to the sac is an
active process, while the ow of tears into the
nasolacrimal duct is the passive process.
7.6.1 Pathology—Dacryocystitis
The most common cause is blockage of the nasolacrimal duct, leading to inammation of the sac.
It occurs due to:
• Structural limitation—congenital incomplete
canalization (Hasner’s valve), narrow osseous
nasolacrimal duct, grossly deviated nasal
septum, inferior turbinate hypertrophy, polyp
or tumour.
• Infection from surrounding structures—nasal
infection, ethmoidal inammation, conjunc-
tival infection, long-standing nasal packs.
• General infection—Inuenza, chickenpox.
7.6.2 Preoperative Tests/
Investigations
1. ROPLAS—“Regurgitation on pressure over
the lacrimal sac” area—the positive test indicates the blockage of the nasolacrimal duct
(Fig.7.33).
2. Jones dye test—Fluorescein dye is instilled in
the eye. The presence of dye in the nasal
cavity in 5 minutes is considered as normal
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Fig. 7.33 Positive ROPLAS test on right side
functioining lacrimal pump system in the
nasal cavity is considered as normal functioning lacrimal pump system [55].
(a) Positive primary Jones test—no
obstruction.
(b) If dye is not detected in the nose, syring-
ing is done and then uorescein detected,
is labelled positive secondary Jones test,
which signies functional obstruction in
the nasolacrimal duct.
(c) If no uorescein is detected in the nose
even after syringing, it is labelled negative secondary Jones test, which signies
stenosis of puncta or canalicular system.
3. Probing—4% lignocaine drops are instilled in
the eye. The punctum is dilated with
Nettleship’s punctual dilator and Bowman’s
probe. Soft block indicates a canalicular or
common canalicular block whereas hard stop
indicates that the probe is in the lacrimal sac
and is touching the bone.
4. Syringing—the punctum is cannulated with a
soft cannula and saline is injected. No regurgitation is considered as normal functioning drainage system. Canalicular block is considered
when the uid is regurgitated from the same
punctum. Regurgitation through the opposite
punctum is either due to common canalicular
blockage or NLD blockage. In NLD blockage
uid is mixed with mucoid or purulent secretion.
In common canalicular blockage, uid is clear.
5. Radiology—T2-weighted images of MRI is
helpful in detecting obstruction site exactly
within nasolacrimal duct and thus planning for
correct endoscopic procedure [56]. The sensi-
239
tivity of CT and MRI can be improved by
injection of contrast (Dacrocystrography). In
dacroscintigraphy, technetium 99 is placed on
the ocular surface. The canaliculi and sac are
visible within 10–15s. The dye appears in the
nasal cavity after 10–30 min intervals.
Dacroscintigraphy is not useful because of
poor resolution and poor anatomical detailing.
The indications for dacryocystorhinostomy
(DCR) is obstruction of the nasolacrimal duct not
responding to conservative treatment (like hot
compresses, massage, probing and intubation) in
children [
57], dacryocystitis with NLD
obstruction, mucocele with NLD obstruction,
congenital stula and posttraumatic NLD
obstruction with epiphora. DCR can be done by
endoscopic or open approach. ENT surgeons are
more familiar with endoscopic DCR.The advantages of Endoscopic DCR are scarless surgery,
preservation of orbicularis oculi pump mechanism. It also allows simultaneous correction of
intranasal pathology and results of endoscopic
DCR are comparable with external DCR [58].
The prerequisite for success endo DCR is correct
identication of lacrimal sac and prevention of
restenosis. Pre-existing anatomical variations
such as concha bullosa, septal deviation, agger
nasi cells and lateralization of uncinate process
can increase the risk of failure as they require
more excision of mucosa for exposure. Bony
window can be mal- positioned or incomplete due
to anatomical variations [
59].
7.6.2.1 Surgical Technique
forEndoscopic DCR
The key landmark is the ridge formed by the
frontal process of maxilla at the anterior attachment of the middle turbinate, anterior to uncinate
process, on the lateral nasal wall [60]. The sac is
located at and anterior to the axilla of middle turbinate or maxillary line in around 95% of cases
(Fig.7.34).
The ap elevation is started with two separate
incisions 8 mm above and below the axilla of
middle turbinate or it can be started with a vertical curved anterior incision given 1 to 1.5cm to
the base of uncinate process vertically down till
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the anterior end of the middle turbinate than two
horizontal incision (Fig.7.35).
The overlying mucosa is separated using a
blunt dissector and this strip of mucosa is removed
using a pair of through-cut forceps. The Kerrison’s
bone punch is hooked against the posterior part of
the anterior lacrimal crest (Fig. 7.36) and bone
removed working from posterior thin bone to anterior thick bone. A wide bony window is made of
the size of approximately 12–15mm (Fig.7.36).
Bone can also be removed by drilling, chisel and
hammer or laser. The use of powered instruments
has not shown an added advantage on surgical success with cold instruments [61, 62]. Periosteum
and sac wall incised vertically using sickle knife or
12 number blade, pus drained, suction cleaning
done (Fig.7.36). The whole of the medial wall of
the sac can be removed or anterior-based ap can
be created to minimize mucosal trauma. Nasal
mucosal ap can be joined with posterior wall of
ML
MT
Fig. 7.34 Relationship of sac with maxillary line (ML)
and anterior end of the middle turbinate (MT) (Courtesy—
Dr. Hitesh Verma, Associate Professor, AIIMS, New
Delhi, India)
de f
Fig. 7.35 The surgical steps of ap elevation. (a) local
inltration, (b) site of upper incision, (c) site of lower
incision, (d) two horizontal incision lines, (e) joining of
horizontal incision, (f) posterior-based ap. Maxillary line
(ML) (Courtesy—Dr. Hitesh Verma, Associate Professor,
AIIMS, New Delhi, India)
ML
Flap
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