gms | German Medical Science

ESBS 2005: Skull Base Surgery: An Interdisciplinary Challenge
7. Kongress der Europäischen Schädelbasisgesellschaft & 13. Jahrestagung der Deutschen Gesellschaft für Schädelbasischirurgie

18. - 21.05.2005, Fulda

Reconstructive aspects in anterior skull base surgery

Meeting Contribution

Suche in Medline nach

  • E. Nkenke - Department of Oral & Maxillofacial Surgery, University of Erlangen-Nuremberg, Erlangen, Germany
  • M. Fenner - Department of Oral & Maxillofacial Surgery, University of Erlangen-Nuremberg, Erlangen, Germany
  • F.W. Neukam - Department of Oral & Maxillofacial Surgery, University of Erlangen-Nuremberg, Erlangen, Germany

ESBS 2005: Skull Base Surgery: An Interdisciplinary Challenge. 7th Congress of the European Skull Base Society held in association with the 13th Congress of the German Society of Skull Base Surgery. Fulda, 18.-21.05.2005. Düsseldorf: German Medical Science GMS Publishing House; 2009. Doc05esbs07

DOI: 10.3205/05esbs07, URN: urn:nbn:de:0183-05esbs077

Veröffentlicht: 27. Januar 2009

© 2009 Nkenke et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.de). Er darf vervielfältigt, verbreitet und öffentlich zugänglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Abstract

The treatment of malignancies of the anterior skull base is a coordinated multi-specialty approach that combines neurosurgery, otorhinolaryngology and oral and maxillofacial surgery. The reconstruction of the defects caused by tumor resection focuses on the separation of the intracranial contents from the facial bones and the re-establishment of an unobtrusive facial appearance. For an effective reconstruction regional and microvascular soft tissue flaps, grafting with autogenous bone and resorbable osteosynthesis plates play a major role.

Anterior skull base tumors are managed using intracranial, extracranial or combined approaches. For the reconstruction of bony defects of the skull base, calvarial split bone grafts are used frequently. The fixation of the grafts can be carried out with resorbable plates in order to avoid the necessity of removal to a later point of time. For larger defects that may combine skull base defects and defects of bone and soft tissue of the face, the reconstructive options include myocutaneous and osteomyocutaneous microvascular flaps harvested from forearm, upper arm, fibula or the scapula.

The different reconstruction techniques help to safely avoid cerebral spinal fluid leakage. The variety of techniques used for structural reconstruction of skull base and adjacent defects can be applied with a minimal complication rate in the patients. Intracranial abscess or osteomyelitis have not been encountered. Loss of bone grafts or complete necrosis of soft tissue flaps have not been observed.

Although sophisticated reconstruction techniques are applied after the resection of anterior skull base malignancies, postoperative complications only occur in a minimal number of patients. Even the frequent application of postoperative irradiation did not seem to affect the graft survival. The different reconstruction techniques can be considered to be well established. The use of resorbable plates helps to reduce the number of secondary surgery for plate removal.


Text

Introduction

The development of skull base surgical approaches and their increasing use have improved treatment of malignant tumors of the skull base. Skull base approaches have allowed for successful resection of many tumors once considered inoperable. Skull base tumors present numerous surgery-related problems because of involvement of functional structures, difficult access, and the creation of large defects after removal [1].

However, the technical development of anterior skull base surgery has had major impact on the long-term survival and quality of life in patients with lesions in this region [2]. Reconstruction of skull base and craniofacial defects is essential after tumor excision in order to

a) form a watertight dural seal,
b) provide a barrier between the contaminated nasosinusoidal space and the sterile subdural component,
c) prevent airflow into the cranial space,
d) maintain a functional sinonasal system,
e) provide an unobtrusive facial appearance [3].

Therefore, the treatment of malignancies of the anterior skull base is a coordinated multi-specialty approach that combines neurosurgery, otorhinolaryngology and oral and maxillofacial surgery [4]. For an effective reconstruction regional and microvascular soft tissue flaps, grafting with autogenous bone and resorbable osteosynthesis plates play a major role.

It is the aim of the present paper to present some of the techniques used for the reconstruction of hard and soft tissue defects caused by tumor resection involving the anterior skull base.

Materials and methods

In the preoperative period, proper patient selection and delineation of surgery related goals are the most important elements in achieving good long-term results. Malignant skull base disease is heterogeneous, often involving uncommon tumors as reflected by the literature [5].

Multimodality treatment is often indicated, and the proper use and timing of adjunctive therapies is a critical consideration in the management of a patient with a skull base tumor. In addition a biopsy sample should be obtained when possible prior to resection so that surgery can be planned in the light of the known behavior of the lesion [6].

Several radiographic features necessitate preoperative consideration, particularly when gross-total resection is the goal. Orbital involvement of the malignant process may require enucleation of the eye, or it may risk visual deficit if the eye is to be preserved. The incidence of postoperative cerebrospinal fluid leakage and meningitis correlates with involvement of dura and brain. When the lesion involves major arteries or dural sinuses, the risk of intra- and postoperative hemorrhage as well as arterial or venous infarction are present. Proximity or involvement with cranial nerves and the cavernous sinus will greatly increase the risk to these structures. Preoperative radiography can typically identify the structures and potential complications of particular significance for a given lesion. When planning surgery, the surgeon must then focus on minimizing the occurrence of these complications.

Primary closure of the dura is performed whenever possible. A graft of temporalis fascia is used if the defect is limited. Galeal flaps can be adopted. In cases of extensive skull base defects, large fascia lata sheaths are harvested. The size of the fascia used for reconstruction is tailored to the dimensions of the dural and skull defects. The fascia is tacked under the edges of the dura and carefully sutured in place. The repaired dural defect is then covered with a second layer of fascia applied against the entire undersurface of the ethmoidal roof, the sella, and the sphenoidal area. Fibrin glue is used to provide additional protection against cerebrospinal fluid leakage.

After removing all the mucosa from the undersurface, the earlier osteotomized segments are repositioned in their original anatomical places and fixed using resorbable plates, preferably, if there is no infiltration of the tumor into the bone.

When the tumor involves the nasal bone or other frontoorbital segments, split calvarial bone graft or posterior frontal sinus wall is used. A bone graft can also be used for posterior nasal support if the nasal septum has been resected. Reconstruction of the medial orbital wall is performed only in cases in which the total removal of this segment is necessary or if the periorbit is resected. In cases of eye globe exenteration, a temporalis muscle flap is used to cover the orbital socket.

For larger defects that may combine skull base defects and defects of bone and soft tissue of the face, the reconstructive options include myocutaneous and osteomyocutaneous microvascular flaps harvested from forearm, upper arm, fibula or the scapula. Microvascular anastomosis is frequently carried out with branches of the external carotid artery and branches of the internal jugular vein. Especially in cases of planned adjuvant radiotherapy it is important to wrap the frontonasoorbital segment with a well vascularized soft tissue cuff in order to prevent osteoradionecrosis.

Postoperatively, the patients are immediately transferred to the critical care unit for 24 hours. The patients stay in hospital during the complete period of wound healing. After dismissal from the hospital the patients are followed up on a regular basis in monthly intervals. During the follow-up often several additional procedures have to be performed in order to improve the facial appearance.

Results

There is no significance in age or sex between patients affected by malignant and benign tumors of the anterior skull base. The most common malignant tumor is the squamous cell carcinoma. The most common benign lesion is the menigioma. Extracerebral radical tumor resection can be achieved frequently, while this is difficult in cases where an intracerebral invasion of the tumor has occurred.

Craniofacial reconstructions have to be adopted, when the tumor resection produces a significant osseous defect in the orbital walls, nasal bone, or anterior frontal sinus wall. The complication rates associated with these reconstructive procedures are below 6% for cerebrospinal fluid leakage, intracranial infection, and tension pneumocephalus. The complication rates in cases of benign and malignant tumors are similar. The patients with cerebrospinal fluid leakage are successfully managed by conservative bed rest and lumbar drainage. Minor complications including agitation and disorientation and donor site cellulites do not cause the need for additional interventions.

After Microvascular reconstruction flap necrosis is an exception. The oncological outcome is favorable. During the follow-up, additional reconstructive procedures have to be carried out. They comprise thinning of the soft-tissue flaps, improvement of the facial contours by augmentation with autogenous bone or alloplastic implants, and the installation of extraoral implants for fixation of epistheses in resected facial regions like ear and eye that cannot be reconstructed in a sufficient manner by autogenous grafts.

After extended skull base resections and reconstructions, long term pain management of the patients can be carried out successfully with only a limited number of patients requiring occasional or daily analgesics. Other quality-of-life issues are determined by the location of the lesions, the extent of resection and which cranial nerves have to be sacrificed. Patients who undergo resection for a lesion of the anterior skull base show favorable results concerning quality of life.

Discussion

As techniques for craniofacial resection and skull-base surgery have evolved, the limits of respectability have expanded [7]. The progress in surgical procedures for neoplasms of the anterior skull base has been accompanied by advances in imaging techniques that have improved the diagnostic capabilities and the ability to determine the extent of disease and to monitor disease recurrence.

Technical surgical approaches to the skull base have progressed to provide excellent exposure and extirpative capabilities. Moreover, advances in reconstructive techniques adopting safe and effective free tissue transfer allow extensive resections in which intracranial-extracranial communications can be effectively separated [8].

The psychosocial and functional effects of craniofacial and skull-base surgery continue to gain attention. The effects on patients who undergo this surgery range from minimal esthetic alterations to major functional impairment, including multiple cranial nerve deficits that affect facial expression, deglutition, airway protection, and speech. The psychosocial effects may be profound and require expenditure of resources [2].

In the management of patients with neoplasms requiring skull-base resection, curability, esthetics, function, pain management, and quality of life must be addressed before surgical intervention. With the rapid development of free tissue transfer and the ability to widely extirpate extensive malignant neoplasms involving the skull base, dura, or both, the multi-disciplinary skull-base surgery team can resect these neoplasms with ease that was impossible previously because of the risk of morbidity [9].

The direct complications of Microvascular surgery are acceptable. The success rates approach 100% [2]. The discussion of the advantages of the low complication rate of free tissue transfer for cranial base reconstruction must also emphasize the reduction in operative morbidity and mortality and the decreased rate of serious infection complications, including meningitis and formation of cerebral abscess. Nevertheless, to date many questions about the effects of free tissue transfer, including donor-site morbidity, duration of anesthesia, and postoperative recovery time are unanswered.


References

1.
Teknos TN, Smith JC, Day TA, Netterville JL, Burkey BB. Microvascular free tissue transfer in reconstructing skull base defects: lessons learned. Laryngoscope. 2002;112:1871-6.
2.
Clayman GL, DeMonte F, Jaffe DM, Schusterman MA, Weber RS, Miller MJ, Goepfert H. Outcome and complications of extended cranial-base resection requiring microvascular free-tissue transfer. Arch Otolaryngol Head Neck Surg. 1995;121:1253-7.
3.
Coleman JJ. Microvascular approach to function and appearance of large orbital maxillary defects. Am J Surg. 1989;158:337-41.
4.
Fliss DM, Zucker G, Amir A, Gatot A. The combined subcranial and midfacial degloving technique for tumor resection: report of three cases. J Oral Maxillofac Surg. 2000;58:106-10.
5.
Shah JP, Kraus DH, Bilsky MH, Gutin PH, Harrison LH, Strong EW. Craniofacial resection for malignant tumors involving the anterior skull base. Arch Otolaryngol Head Neck Surg. 1997;123:1312-7.
6.
Donald PJ. Complications in skull base surgery for malignancy. Laryngoscope. 1999;109:1959-66.
7.
Schramm VL Jr, Myers EN, Maroon JC. Anterior skull base surgery for benign and malignant disease. Laryngoscope. 1979;89:1077-91.
8.
Jones NF, Schramm VL, Sekhar LN. Reconstruction of the cranial base following tumour resection. Br J Plast Surg. 1987;40:155-62.
9.
Ketcham AS, Wilkins RH, Van Buren JM, Smith RR. A combined intracranial facial approach to the paranasal sinuses. Am J Surg. 1963;106:698-703.