gms | German Medical Science

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

18. - 21.05.2005, Fulda, Germany

Management of postoperative epidural abscess after skull base surgery

Meeting Contribution

  • Takeshi Mikami - Department of neurosurgery and plastic surgery, Sapporo Medical University, Sapporo, Japan
  • Yoshihiro Minamida - Department of neurosurgery and plastic surgery, Sapporo Medical University, Sapporo, Japan
  • Kiyohiro Houkin - Department of neurosurgery and plastic surgery, Sapporo Medical University, Sapporo, Japan
  • Takatoshi Yotsuyanagi - Department of neurosurgery and plastic surgery, Sapporo Medical University, Sapporo, Japan

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. Doc05esbs16

doi: 10.3205/05esbs16, urn:nbn:de:0183-05esbs168

Published: January 27, 2009

© 2009 Mikami et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.




Surgical site infections (SSIs) after skull base surgery are relatively common and potentially serious infections. We performed a retrospective study to determine the best method for management of postoperative epidural abscess and the incidence in our series.

Materials and Methods

Between 1997 and 2004, we treated 5 cases of postoperative epidural abscess subsequent to skull base surgery. This series excluded conventional methods; namely, lateral suboccipital approach, basal interhemispheric approach, and trassphenoidal approach. The 5 cases, consisting of 1 referred case and 4 cases of our series, ranged in age from 35 to 67 (mean age of 49.6 years old). All patients were men, and no cases were combined with meningitis.

Our strategy for SSIs was to treat it conservatively with antibiotics at first, and focalize it as much as possible. After focalizing the inflammation, we drained the abscess and removed the bone flap or foreign body. If the ulceration of the skin was enlarged and the abscess was not cured, a myodermal flap transfer was then performed. The steps of myodermal flap transfer were as follows:

Preparation of myodermal flap,
Debridement of granulomatous inflammation,
Suture the muscle directly on the dural edge,
End to end anastomosis of artery and vein graft,
Skin closure without cranioplasty.


3 of the 5 cases underwent anterior craniofacial resection. All 3 had intradural lesion. The other cases underwent translabyrinthin approach and transcondylar approach. Surgical wound classification [1] consisted of 1 case of Class III and 4 cases of Class II. Entry of the surgical wound into the nasal cavity was occurred in 3 of the 5 cases. CSF leak occurred in 1 case. Radiation was performed in 2 cases after initial surgery. In 4 of the 5 cases, the pathogen of the abscess was MRSA. 1 case was treated with antibiotics only, and 1 case was cured after drainage and removal of the bone flap. Myodermal flap was performed in 3 cases. Before myodermal flap transfer, the infections were focalized as much as possible. Preoperative mean CRP was 0.88, and mean WBC was 6200. In 1 of these 3 cases, flap failure occurred, but was resolved with an additional procedure.

In our series between 1997 and 2004, a total of 4 postoperative SSIs were identified in 78 patients undergoing skull base surgery. All cases were epidural lesions, and there was no occurrence of simultaneous meningitis or encephalitis. Surgical infection rate in our series was 5.1%. As regards the approach, anterior craniofacial resection was performed 3 of the 4 cases. In this series, the incidence of surgical infection in anterior craniofacial resection was significantly higher than it was in the other procedures (p<0.05).


A 67-year-old with sinonasal carcinoma with intracranial extension underwent removal of tumor including dura mater and eyeball on May 7, 2001. A fascia lata was used for the dural plasty, and a rectus abdominis myodermal flap was folded to repair the defect. Postoperatively, focal radiation (60Gy) and chemotherapy were performed. An infectious sign was found 4 months later. He was treated with antibiotics, drainage of abscess and removal of bone flap. However it did not heal, so wide debridement and additional transplant of rectus abdominal myodermal flap was performed. Muscle of the myodermal flap was fixed directly on the dural edge (Figure 1 [Fig. 1]).


The rate of SSIs in clean neurosurgical operations with prophylactic antibiotics is 0.3% to 3.0%. A variety of risk factors for SSIs in neurosurgery have been reported. Korinek [2] reported that the presence of a CSF leak and subsequent operation are independent risk factors, and emergency surgery, clean-contaminated and dirty surgery, an operative time of longer than 4 hours, and recent neurosurgery are independent predictive risk factors for SSIs. Erman [3] reported that age, certain types of operation such as shunt surgeries, placement of foreign bodies, diabetes mellitus, and ICP monitoring were substantial risk factors for postoperative SSIs. In the field of skull base surgery, the incidence of intracranial infections after anterior skull base surgery was high. The rate is reported to be between 4 and 37%. Risk factors are previous craniotomy, radiotherapy over 60Gy, and frontal lobectomy [4]. To prevent epidural abscess, we should avoid excessive lumber drainage, because dead space of the epidural area promotes epidural abscess. In the recent cases of our series, lumber drainage was used only during surgery. After the surgery, we pulled out immediately.

When SSIs occurred, we treated it conservatively with antibiotics as far as possible. We think that it is important to focalize the infection, and surgical treatment is not initiated until CRP< 2, except when mass effect was present. Myodermal flap transfer was useful for the large ulceration of the skin, and in cases which did not cure with conventional methods.

The advantages of myodermal flap transfer are feasible wide debridement, sufficient blood circulation, excellent drug delivery, resistance to infection, flexible dural reconstruction, and easy control of the dead space [5]. However, there are some disadvantages; donor organs are from different areas, and cosmetic problem exist. Therefore, myodermal flap transfer should only be performed in certain, limited cases.


It is important to manage the abscess by focalizing the inflammation as much as possible. Use of the myodermal flap transfer allows sufficient blood circulation, and aids resistance to infection. And it was easy to control of the skin defect and dead space. It may therefore be useful for intractable postoperative epidural abscess.


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