Endoscopic skull base surgery a brief

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Endoscopic skull base surgerya brief

• Dr.Mohammed Tariq FRCS
• Associate professor ENt Unit II SIMS
• Services hospital,Lahore.

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History

• The earliest approaches to brain surgery were at
  the skull base.
• 1870 .. Francesco Durante was the first to
  remove an olfactory groove meningioma from the
  skull base in a 35-year-old woman who presented
  with proptosis, loss of smell, and memory
  impairment
• 1879 ..William Macewen contributed further

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Subsequent innovations

• Sir Victor Horsley (18571916) sectioned the
  posterior root of the trigeminal nerve for pain
  relief,
• Sir Charles Ballance (18561936) reported one of
  the earliest cases of acoustic tumor removal,
• Fedor Krause (18571937) from Germany, Thierry de
  Martel (18751940) from France, and others made
  major contributions to skull base surgery

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feasibility

• With this approach it is possible to expose
  the intradural cranial base, from the olfactory
  groove to the odontoid process of C2.
• The most common surgery related problems are
  related to the prevention of postoperative CSF
  leakage and, in cases involving the lower skull
  base, the usual issues of stability of the
  craniovertebral junction.
• Nevertheless, the potential benefits of such
  an approach, which allows exposure of the
  surgical area with no skin incision or
  neurovascular retraction, cannot be overestimated.

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The midline skull base

• is an anatomical area that extends from the
  anterior limit of the cranial fossa down to the
  anterior border of the foramen magnum.
• Resection of lesions involving this area requires
  a variety of innovative skull base approaches.
• These include anterior, anterolateral, and
  posterolateral routes, performed either alone or
  in combination, and resection via these routes
  often requires extensive neurovascular
  manipulation.

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The major potential advantage

• it provides a direct anatomical route to the
  lesion without traversing any major neurovascular
  structures, obviating brain retraction.
• Many tumors grow in a medialtolateral direction,
  displacing structures laterally as they expand,
  creating natural corridors for their resection
  via an anteromedial approach.

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Potential disadvantages

• the relatively restricted working space
• the danger of an inadequate dural repair with
  cerebrospinal fluid (CSF) leakage .These
  approaches often require a large opening of the
  dura mater over the tuberculum sellae and
  posterior planum sphenoidale, or retroclival
  space. In addition, they typically involve large
  intraoperative CSF leaks, which necessitate
  precise and effective dural closure
• potential for meningitis

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accuracy and safety

• the constant improvements in diagnostic imaging
  techniques and the increasing use of image
  guidance systems during endoscopic endonasal
  procedures has provided increasing accuracy and
  safety for this approach, allowing improved,
  constant surgical orientation in an anatomically
  complex area.

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Endoscopic trajectories

• different areas of the midline skull base
  exposed through the endoscopic endonasal
  approach.
• to the olfactory groove
• to the sella turcica and planum sphenoidale
• to the clivus
• to the craniovertebral junction and foramen
  magnum.

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Currently approach provides

• the definitive treatment of choice for most
  pituitary adenomas,
• craniopharyngiomas and meningiomas of the sellar
  region.
• The elegant minimally invasive transnasal
  endoscopic approach to the sella turcica and the
  anterior skull base has added a new dimension of
  versatility to pituitary surgery and can be
  adapted to many lesions in the region.

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removal of pituitary tumors

• The refinement of minimally invasive endoscopic
  techniques has resulted in 'pure' endoscopic
  endonasal trans-sphenoidal surgery, which is a
  relatively new approach for the removal of
  pituitary tumors.

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removal of pituitary tumors The technique

• wide anterior sphenoidotomy
• detachment of the septum from the sphenoid face
  avoiding the use of a trans-sphenoidal retractor
  and any intraoral or nasal incisions.
• Straight and angled endoscopes are used
  throughout the procedure to provide a wide view
  of the sella and are manipulated by a co-surgeon.

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an improvement over pituitary microsurgery

• decreased post-operative morbidities
• a shortened postoperative stay
• it eliminates the need for packing
• providing an opportunity to monitor the sella
  after surgery.
• It incorporates image-guided surgery, with the
  fusion of computer tomography and magnetic
  resonance imaging
• employs new and dedicated instrumentation.

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Future advancements

• in intraoperative imaging,
• cranial base reconstruction, and
• robotics will make this technique even more
  successful

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unique reconstructive challenges

• The creation of large defects of the bone and
  dura endoscopically presents unique
  reconstructive challenges.
• A layered reconstruction of the dura with inlay
  and onlay fascial grafts covered with fat grafts
  is an effective technique for repair.
• An intranasal balloon catheter is used to provide
  counterpressure in the early phase of healing and
  
• a lumbar spinal drain is a useful adjunct in
  patients at increased risk of a cerebrospinal
  fluid leak.
• Vascularized flaps may be necessary in some
  patients receiving radiation therapy.
• Continued advances in surgical technology and the
  introduction of new biomaterials will facilitate
  the reconstruction of skull base defects
  following surgery.

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Endoscopic experience

• with the repair of small cranial base defects
  following
• trauma,
• sinus surgery, and
• spontaneous CSF leaks (meningoencephaloceles)
• has demonstrated a high rate of successful
  repair using a variety of techniques.

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Endoscopic experience

• 1 Success does not appear to be dependent on the
  type of reconstructive material, repair
  technique, or use of lumbar spinal drainage.
• 2 A special population of patients that appear to
  be at increased risk of recurrent CSF leak are
  those presenting with spontaneous CSF leaks.
• 3 These patients are characteristically obese,
  middle-aged females and measurement of CSF
  pressures following repair often confirms occult
  hydrocephalus. Despite initial success, such
  patients remain at risk for recurrent CSF leaks
  months to years following repair

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vascularized tissue flaps

• Some populations of patients may require
  reconstruction with vascularized tissue flaps due
  to the volume of the defect or the lack of
  vascularized tissue (prior irradiation).
• Options include a pedicled pericranial scalp
  flap, temporoparietal fascial flap, or
  microvascular free flap

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• Dural defect following endoscopic craniofacial
  resection of a neuroendocrine carcinoma of the
  anterior cranial base.

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• A synthetic dural substitute (DuraGen) is placed
  intradurally over the surface of the exposed
  brain so that the dural edges overlap the inlay
  graft.

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• The first fascial graft (Alloderm) is sutured to
  the dural margins.

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• Nitinol U-clips are used to anchor the fascial
  graft to prevent migration or displacement by CSF.

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• Fat grafts cover the fascia and are in contact
  with the surrounding bone.

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• A Foley balloon catheter crosses the nasopharynx
  posterior to the nasal septum, prior to inflation
  with saline. The surface of the fat graft is
  covered with Surgicel to form an adherent crust.

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• thanks