|Year : 2006 | Volume
| Issue : 2 | Page : 56-59
Supraorbital 'keyhole' approach for craniopharyngioma
Vikram Karmarkar, Chandrashekhar Deopujari, Rajan Shah, Rakeshkumar Luhana
Department of Neurosurgery, Bombay Hospital Institute of Medical Sciences, Mumbai, India
126B, MRC 1st Floor, Bombay Hospital, 12 New Marine Lines, Mumbai - 400 020
Source of Support: None, Conflict of Interest: None
| Abstract|| |
The supraorbital 'keyhole' craniotomy with an eyebrow incision is a versatile minimally invasive keyhole procedure for anterior and midline skull-base lesions. Experience with this technique for craniopharyngioma is presented, describing the surgical procedure with a brief literature review.
Keywords: Craniopharyngioma, keyhole surgery, minimally invasive approach, supraorbital.
|How to cite this article:|
Karmarkar V, Deopujari C, Shah R, Luhana R. Supraorbital 'keyhole' approach for craniopharyngioma. J Pediatr Neurosci 2006;1:56-9
Minimally invasive 'keyhole' approaches are proposed as an alternative to more extensive skull base approaches as well as 'classic' approaches for many indications. The supraorbital keyhole craniotomy for anterior and midline skull-base lesions utilizes high-performance microscopes, shaft instruments and endoscope assistance to reduce the size of bone removal required, while effectively retaining the same exposure and other advantages afforded by larger craniotomies.
| Historical Evolution|| |
In the last decade, Perneczky and colleagues popularized the keyhole concept and the technique commonly used today, the supraorbital keyhole craniotomy. The evolution, however, began with Fedor Krause's description of the supraorbital subfrontal approach for a skull base meningioma, in 1908. In 1913, Frazier advocated a supraorbital ridge resection, which was found useful in surgery for pituitary adenomas.
More recently, Jane and Delashaw, described a supraorbital craniotomy with fracture of the anterior orbital roof in the approach to orbital tumors. Other variants have been proposed by Al-Mefty et al.
However, the concept of a minicraniotomy using a 'keyhole' approach was advocated and popularized by Perneczky and colleagues in the 1990s. They advocated that the word 'keyhole' denotes a 'concept rather than a dimension' and not so much the actual size of bone removal., This concept and this versatile approach have found applications in treating a variety of pathologies in the anterior skull base, ranging from aneurysms to tumors, viz., pituitary adenomas, meningiomas and craniopharygiomas.,,,
A lumbar drain was inserted in most of our cases. Drainage of cerebrospinal fluid (CSF) allows brain relaxation and reduces the retraction required on the frontal lobe.
After general anesthesia, the patient is placed in the supine position, the head elevated 15° above the chest. The head is then rotated to the opposite side by 15-45°. The degree of rotation depends on the location of the lesion. For parasellar lesions 15° suffices, lesions near the midline require 30°, while more rotation is useful for contralateral lesions. A right-handed surgeon would require more rotation to the right when operating on left-sided lesions. The next step in positioning the head is to extend or retroflex the head. This important step helps the frontal lobe to fall backward with gravity, and with CSF drainage, reduces the retraction required. The end point of position is such that the malar prominence is the highest point. We generally use a three-pin skull-fixation device. The eyelids are taped shut with a Micropore™ adhesive tape.
The anatomical landmarks are then marked: the supraorbital notch, the superior temporal line, the orbital rim. The incision is marked - beginning just lateral to the supraorbital notch, extending within the eyebrow and extending a few millimeters beyond the lateral margin of the eyebrow. The eyebrow is not shaved [Figure - 1]a, b.
The skin and subcutaneous tissue are incised. This exposes the frontalis muscle and the anterior attachment of the temporalis muscle. The frontalis and the pericranium are raised as a flap with the base on the orbital rim. The temporalis is stripped off its attachment to the superior temporal line.
The craniotomy is begun by placing the 'key' burr hole behind the superior temporal line and 1.5 cm above the frontozygomatic suture. This gives access to the frontal base. A craniotome is used, first to make a basal cut along the supraorbital rim medial enough to avoid the supraorbital foramen and the frontal air sinus. A second curvilinear cut is made from the burr hole to join the medial end of the first cut. The bone flap thus raised should be approximately 2.5 cm in width and 1.5-2 cm in height for unrestricted use of microinstruments and endoscope. The bone flap is fixed after surgery using mini plates or Craniofix™ [Figure - 2]a, b. The next maneuver is to drill the inner surface of the inferior margin (orbital ridge) of the craniotomy to smooth the edge and to afford a few more millimeters for a more basal approach. At a younger age, the orbital roof may be more oblique and irregular and may need to be smoothened by drilling. The lumbar drain is opened after the burr hole is made. A curved durotomy is made based inferiorly and tacked .
The frontal lobe tends to fall back. A self-retaining retractor may be used initially till adequate CSF has drained. The drain is closed after adequate CSF drainage. The Sylvian fissure can be easily split, as necessary, medial to lateral or from the Sylvian point inwards, the orientation being more anterior. The optic nerve, the chiasm, the orbital roof, the clinoids, cavernous sinus (roof and lateral wall), the ICA and its branches and P1, P2 are accessible ipsilaterally [Figure - 3]a, b, c.
Adjuncts for surgery
Lumbar CSF drainage is of immense help. Improved techniques in neuroanesthesia contribute to optimum brain relaxation. Certain modifications in instrumentation are required for facility of this approach. Special instruments, especially of the shaft type, are invaluable when working in the depth as opening and closing of the conventional microinstruments is not possible with the small opening in the skull. The neuroendoscope is a force multiplier enhancing vision in the depth and in corners; it allows more complete and safe surgery [Figure - 4],[Figure - 5]a-d.
Twenty-nine patients have been operated utilizing this approach for a variety of lesions, including aneurysms, cysts and tumors. This includes seven patients with craniopharyngioma [Table - 1].
The utility of the supraorbital keyhole approach in tackling craniopharyngiomas depends on the growth pattern and the morphology of the tumor. This approach is useful in solid/cystic lesions projecting into the suprasellar, parasellar, interpeduncular and anterior fossa, predominantly projecting to one side. Pure intraventricular lesions are not suited for this maneuver.
This approach allows access to this tumor through the inter-optic, optico-carotid, lateral carotid corridors. Sylvian fissure opening allows dissection of the tumor from retrocarotid space and the interpeduncular fossa.,,
Six primary craniotomies and one craniotomy for recurrence were performed. Satisfactory removal could be achieved in five. One patient had significant residual calcified mass, which has remained unchanged over the last 3 years. Another patient needed a second-stage craniotomy for a predominantly intraventricular cystic recurrence .
No complications related to the technique of the procedure were encountered [Figure - 6][Figure - 7][Figure - 8].
| Discussion|| |
Apart from the decreased dissection and smaller but strategic bone opening, the trajectory of approach is more anterior as compared to the pterional approach. This is similar to the basal frontal approach but without the additional morbidity associated with opening of the frontal sinus, and it avoids avulsion of olfactory fibers.
Additional advantages include minimal dissection of the temporalis muscle and hence reduced chances of postoperative atrophy of the temporalis muscle. Damage to the supraorbital nerve is avoided by staying lateral to the supraorbital notch.
The other advantages related to the small opening are less exposure of the brain surface to air and preventing accidental injury of the cortex.
The limitations of this technique are lesions associated with severe brain swelling and purely intraventricular lesions. A relative contraindication is a large frontal air sinus.
The complications reported are- paresis, usually temporary, of the frontalis muscle due to damage to the frontal branch of the facial nerve; eyelid and orbital swelling may occur in case of breach of the periorbita while drilling the orbital roof.
| Conclusion|| |
Supraorbital keyhole craniotomy has proved to be a minimally invasive alternative technique to approach midline skull-base lesions. Endoscope assistance gives added advantage in deeper locations and corners. Experience with craniopharyngioma has been encouraging for radical excision with safety.
| References|| |
|1.||Krause F. Chirurgerie des Gehirns und Ruckenmarks nach eigenen Erfahrungen. Berlin, Urban and Schwarzenberg; 1908. |
|2.||Frazier CH. An approach to the hypophysis through the anterior cranial fossa. Ann Surg 1913;1:145-50. |
|3.||Jane JA, Park TS, Pobereskin LH, Winn HR, Butler AB. The supraorbital Approach: Technical note. Neurosurgery 1982;11:537-42. [PUBMED] [FULLTEXT]|
|4.||Delashaw JB, Jane JA, Kassel NF, Luce C. Supraorbital craniotomy by fracture of the anterior orbital roof: Technical note. J Neurosurg 1993;79:615-8. |
|5.||Al-Mefty O. The supraorbital-pterional approach to skull base lesions. Neurosurgery 1987;1:474-7. |
|6.||Reisch R, Perneczky A. Ten-year experience with the supraorbital subfrontal approach through an eyebrow skin incision. Neurosurgery 2005;57:ONS242-55. |
|7.||Grotenhuis JA. Comment. Czirjak S, Nyary I, Futo J, Szeifert GT. Bilateral supraorbital keyhole approach for multiple aneurysms via superciliary skin incisions. Surg Neurol 2002;57:314-24. |
|8.||Czirjak S, Nyary I, Futo J, Szeifert GT. Bilateral supraorbital keyhole approach for multiple aneurysms via superciliary skin incision. Surg Neurol 2002;57:314-24. [PUBMED] [FULLTEXT]|
|9.||Mitchell P, Vindlacheruvu RR, Mahmood K, Ashpole RD, Grivas A, Mendelow AD. Supraorbital minicraniotomy for anterior circulation aneurysms. Surg Neurol 2005;63:47-51. [PUBMED] [FULLTEXT]|
|10.||Jho HD. Orbital roof craniotomy via an eyebrow incision: A simplified anterior skull base approach. Minim Invasive Neurosurg 1997;40:91-7. [PUBMED] [FULLTEXT]|
|11.||Wiedemayer H, Sandalcioglu IE, Wiedemayer H, Stolke D. The supraorbital keyhole approach via an eyebrow incision for resection of tumors around the sella and the anterior skull base. Minim Invasive Neurosurg 2004;47:221-5. [PUBMED] [FULLTEXT]|
[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5], [Figure - 6], [Figure - 7], [Figure - 8]
[Table - 1]