Authors of section

Authors

Brian Burkey, Neal Futran

Executive Editors

Gregorio Sánchez Aniceto, Marcelo Figari

General Editor

Daniel Buchbinder

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Radial forearm free flap

1. Introduction

Most often when the orbital content is resected with the skull base neoplasm, free tissue transfer is necessary to provide an adequate amount of vascularized tissue to seal the skull base and restore orbital volume.

The selection of the soft tissue flap is dictated by the volume of the tissue required and vascular pedicle length.

Reconstruction of skull base defect with orbital involvement

The most common indications for central anterior craniofacial resection are:

  • Sinonasal malignancies
  • Olfactory groove tumors
  • meningiomas around the orbit

Goals of reconstruction

Successful reconstruction of the skull base depends on several key principles to minimize the likelihood of perioperative complications and restoration of anatomical boundaries and barriers. Key elements are:

  • Obtain a watertight dural seal
  • Separate intracranial and extracranial cavities
  • Obliterate dead space and/or sinuses
  • Suspend or support neural structures
  • Restore or preserve function and form

Ideal Reconstructive Procedure

The most important element is to use tissues with robust blood supply. Although there are a variety of options, choices can be made based on the following principles:

  • Safety
  • Reliability
  • Single stage procedure
  • Minimal donor site morbidity
  • Tissues must tolerate the burden of healing related to:
    o Radiation therapy
    o Previous chemotherapy
    o Poor vascularity
    o Local contamination

Particular Challenges

Because of the proximity to the skull base to the central nervous system, any complication arising from procedures in this area can be life threatening. Areas to pay specific attention are:

  • Calvarial bone or dural involvement
  • Sinus involvement
  • Inelasticity of scalp
  • Distance to neck vessels
  • Previous treatment
  • Biological tumor behavior

2. Access to the tumor

Some surgeons will elect to place a lumbar drain prior to initiating the procedure, to allow for relaxation of the brain during surgery.

Reconstruction of skull base defect without orbital involvement: Pericranial flap

Tumor access from the cranial side

The tumor is exposed on the cranial side through the coronal approach as well as one of the three following approaches:

The choice should ensure adequate tumor exposure and minimize brain retraction.

anterolateral thigh fasciocutaneous free flap

Tumor access from the nasal side

On the nasal side, the tumor can be exposed via a lateral rhinotomy incision or endonasally with endoscopes.

Reconstruction of skull base defect without orbital involvement: Radial forearm free flap

3. Resection of the tumor

Incision of nasal septum

Using the electrocautery an incision is made through the nasal septum from the top of the nasal vault just down to the premaxillary crest, 1 cm anterior to the tumor margin.

A second incision is made along the premaxillary crest posteriorly to the sphenoid rostrum.

These cuts can also be made endoscopically without a Lateral Rhinotomy.

Reconstruction of skull base defect with orbital involvement

Cranial osteotomies

The tumor is approached from the cranial side.

The frontal lobes are retracted and a small round burr is used to incise the cranial base around the cribriform plate.

Depending on the extension of the tumor, one or both of the lamina papyracea could be preserved.

Reconstruction of skull base defect without orbital involvement: Pericranial flap

The orbital periosteum is elevated on the side without involvement of the globe.

Reconstruction of skull base defect with orbital involvement

The bone of the supraorbital roof is removed with a rongeur. Enough bone is removed to allow for circumferential dissection of the orbital contents.

Reconstruction of skull base defect with orbital involvement: Temporal and pericranial flap

The optic artery and nerve are ligated with 2.0 sutures and divided close to the apex. The orbital contents are separated from the inner eyelid sharply (if the eyelid is preserved).

Reconstruction of skull base defect with orbital involvement: Temporal and pericranial flap

Scissors are used to cut the posterior bony septum.

Reconstruction of skull base defect with orbital involvement: Temporal and pericranial flap

Tumor delivery

The tumor is removed en block with the cribriform segment and submitted for permanent pathological examination.

Surgical margins are now checked with frozen sections to ensure the adequacy of the tumor resection.

Reconstruction of skull base defect with orbital involvement: Temporal and pericranial flap

4. Reconstruction

Harvesting of the flap

The flap is harvested in the standard fashion with the following considerations:

  • An adequate sized flap should be harvested to overcorrect the defect by 30-40 % as atrophy of the tissue will occur over time
  • The vascular pedicle should be followed to its origin to obtain maximal pedicle length
  • The flap is de-epithelialized except for a small skin paddle that will be used as a monitor or to reconstruct the eyelids.
  • The skin paddle should be situated on the proximal end of the free flap.
Reconstruction of skull base defect with orbital involvement: Radial forearm free flap

Insetting and trimming of soft tissue flap

The deep portion of the flap is inset to seal the skull base and sutured to the surrounding tissue with adsorbable sutures.

Reconstruction of skull base defect with orbital involvement: Radial forearm free flap

The pedicle is draped laterally over the preauricular and parotid region.

Reconstruction of skull base defect with orbital involvement: Radial forearm free flap

The surgeon must be aware of the need of removing part of the frontal bone at the time of repositioning the osteotomy flap, thus avoiding compression of the pedicle.

Reconstruction of skull base defect with orbital involvement: Radial forearm free flap

In case the eye lids are not spared, the cutaneous layer visible through the eye defect is marked.

Reconstruction of skull base defect with orbital involvement: Radial forearm free flap

The flap is then retracted sufficiently to de-epithelialize the excess skin so that it fills the cutaneous defect in the eye.

Reconstruction of skull base defect with orbital involvement: Radial forearm free flap

Deep sutures are placed with adsorbable suture material. The skin is then closed with permanent sutures.

Reconstruction of skull base defect with orbital involvement: Radial forearm free flap

Recipient vessels

Some surgeons prefer to use the superficial temporal artery and vein for anastomosis. Oftentimes however, the vein is not a suitable recipient vessel.

Reconstruction of skull base defect without orbital involvement: Radial forearm free flap

Some surgeons prefer to extend the coronal incision into a modified face lift incision into the neck, dissecting the facial vessels and using those for flap anastomosis.

Rarely vein grafts are necessary to lengthen the vascular pedicle to reach the vessels in the neck.

Reconstruction of skull base defect without orbital involvement: Radial forearm free flap

Monitor paddle

In case the eyelids are spared, the monitor paddle is incorporated into the skin incision.

Reconstruction of skull base defect with orbital involvement: Radial forearm free flap

5. Revascularization of flap

The detailed procedure for the revascularization is outside the scope of this surgery reference. However, in short the procedure consists of the following steps:

  • The recipient and the donor vessels adventitia are cleaned under a microscope
  • Appropriate vessel geometry is assured and the vessels are placed into a microvascular clamp and anastomosis carried out using 9-0 nylon sutures
  • Vascularization is restored after both arterial and venous anastomoses are completed
Reconstruction of skull base defect with orbital involvement

6. Aftercare following skull base reconstruction

Postoperative positioning

Keeping the patient’s head in a raised position both preoperatively and postoperatively may significantly improve edema and pain.

Neurological checks

The patients neurological status should be evaluated as soon as it is feasible. Regular postoperative neurological checks should be performed.

Nose-blowing

Nose-blowing should be avoided for at least 3 weeks following frontal sinus and skull base repair.

Medication

The use of some of the following perioperative medication is controversial. There is little evidence to make strong recommendations for postoperative care.

  • Analgesia as necessary
  • Antibiotics (many surgeons use perioperative antibiotics. There is no clear advantage of any one antibiotic, and the recommended duration of treatment is debatable.) The spectrum should be according to the existing bacterial flora, especially in the combined intra and extra cranial procedures.
  • Nasal decongestant may be helpful for symptomatic improvement in some patients.
  • Corticosteroids, may help with postoperative edema.
  • If a free flap is utilized for the reconstruction 100 mg of aspirin/day is recommended.
  • Ophthalmic ointment should follow local and approved protocol. This is not generally required in case of periorbital edema. Some surgeons prefer it. Some ointments have been found to cause significant conjunctival irritation.

Ophthalmological examination

Postoperative examination by an ophthalmologist may be requested. The following signs and symptoms are usually evaluated:

  • Vision
  • Extraocular motion (motility)
  • Diplopia
  • If the patient complains of epiphora (tear overflow), the lacrimal duct must be checked
  • If the patient complains of eye pain, evaluate for corneal abrasion

Note: In case of postoperative diplopia, ophthalmological assessment is needed to identify the cause. Hess-chart testing should be performed if diplopia persists.

Postoperative imaging

A head CT scan is obtained postoperatively to provide a patient baseline and evaluate for intracranial bleeding, dead space, and pneumocephalus.

Subsequent imaging can be based on the patients' postoperative course.

Wound care

Remove sutures from skin after approximately 7 days if nonresorbable sutures have been used. If the patient has had previous radiation, the sutures should be left in for 10 days.
Moisturizing lotion should be used on the skin wounds to minimize excessive scarring after sutures are removed.
Avoid sun exposure and tanning to skin incisions for several months.

Diet

Patients are started on a liquid diet, and advanced to regular diet as tolerated.

Clinical follow-up

Clinical follow-up depends on the complexity of the surgery, and the patient’s postoperative course.
Other issues to consider are:

  • Postoperative headache
  • Dizziness
  • Vomiting
  • Meningitis
  • Anosmia
  • Mucocele formation (can occur years after injury)
  • Sensory nerve compromise
  • Abnormal scarring
  • Alopecia
  • Cranial vault contour deformity

Special considerations

Travel in pressurized aircraft is permitted 4 – 6 weeks postoperatively. Mild pain on descent may be noticed. However, flying in non-pressurized aircraft should be avoided for a minimum of 12 weeks.
No scuba diving should be permitted for at least 12 weeks. Additionally, the patient should be warned of long term potential risks.

Reconstruction with free flap

When a free flap is utilized, it should be regularly monitored to ensure vascular integrity. Physical examination, assessing the flap color, turgidity, and capillary refill should be routine for at least the first 48 hours postoperatively. Hand-held Doppler probes can be used to assess blood flow. In case of doubt of the vitality of the flap, pin-prick assessment with a 25 gauge needle to look for bright red bleeding. In cases of buried flaps, an implantable Doppler placed just distal to the venous anastomosis can be utilized.

Radial forearm free flap
The radial forearm free flap donor site should be closed with a skin graft and a bolster placed over the area. The arm is then cast or placed in a volar splint for 7 days prior to removal to ensure graft take. If bone is taken and the radius plated, appropriate follow-up with an orthopedic or hand specialist should be arranged.

Rectus abdominous and iliac crest
Rectus abdominous and iliac crest donor sites require that the patient not strain or lift heavy objects for at least 4 weeks to avoid hernia formation.

Anterolateral thigh
Patients should avoid climbing stairs for 2-4 weeks after surgery. They should also be observed for seroma formation at the wound bed.
Furthermore, patients often need physical therapy to rehabilitate the donor site.

Latissimus dorsi
There are no special issues for this flap except the suction drains should be left in place for 5-7 days as there is a 40 % risk of seroma formation. If a seroma does occur it can be aspirated with a large gauge needle as necessary.