Extensive Spinal Adhesive Arachnoiditis After Extradural Spinal InfectioneSpinal Dura Mater Is No Barrier to Inflammation Theresa Kra ¨ tzig 1 , Marc Dreimann 2 , Klaus Christian Mende 1 , Ingo Ko ¨ nigs 3 , Manfred Westphal 1 , Sven Oliver Eicker 1 - BACKGROUND: Spinal adhesive arachnoiditis (SAA) is an inflammatory process of the meninges. Cystic changes and cicatrization may lead to neurologic deficits and immobilization. Therapy is difficult and often unsatisfac- tory. We describe 8 cases of extensive SAA after extradural spinal infection. - METHODS: A total of 238 patients with epidural abscess or osteomyelitis were treated at our institution between 2011 and 2018. We identified 8 patients who developed extensive SAA on follow-up. Different forms of the disease, radiologic changes, and potential treatment options are described. - RESULTS: Eight patients developed extensive SAA after either spontaneous epidural infection in 4 cases (50%) or after surgery or steroid injection (50%). Initial treatment for epidural infection was surgery without dural injury in 87.5%. One patient was treated conservatively. SAA was diagnosed 1 month to 8 years after the initial infection, not only in the index region but throughout the whole spine, with varying clinical symptoms. Treatment options such as corticosteroids (n [ 4), thecaloscopy (n [ 1), syringe- subarachnoid shunting (n [ 1), and focal or multilevel arachnolysis (n [ 5) were applied. In 2 patients (25%), a rare complication of internal malabsorptive hydrocephalus had to be treated. Patients showed diverse outcomes at last follow-up (mean, 37 months). - CONCLUSIONS: The prognosis for extensive SAA is poor. Surgical interventions may improve radiologic find- ings and clinical presentation at least temporarily. Even extradural infection can lead to severe SAA. Early surgery with local reduction of the epidural infection might reduce the risk of inflammation passing the dural sac and causing SAA. INTRODUCTION S pinal adhesive arachnoiditis (SAA) is an inflammatory process of the leptomeninges, which was first described by Mendel and Adler as “meningitis serosa spinalis” and by Sir Victor Horsley as “chronic spinal meningitis.” 1,2 It leads to a thickening of the arachnoid membrane, cystic changes in the subarachnoid space, and the development of scar tissue. Resulting cerebrospinal fluid (CSF) disturbances can lead to high-pressure pulsation in the subarachnoid space with possible fluid flow into the spinal cord with edema and cystic formation. 3 A variation of clinical symptoms with back pain in most patients, urinary urgency and incontinence, spasms, burning in ankles and feet, hypesthesia below the affected levels, and paralysis is described. 4-8 Confirmation of diagnosis is made through clinical presentation and magnetic resonance imaging (MRI) of thickened and enhanced meninges. 6,7 The spectrum of the cause changed over the last century. In the first half, the more infectious causes of SAA were described, such as syphilis, tuberculosis, and pyogenic bacteria, and the focus was on the thoracic region, with only 12% lumbar involvement. 9,10 The application of intrathecal oil-based contrast agents was later dis- cussed, and currently, chronic degenerative compression, spinal or periradicular injection, and anesthesia, as well as spinal surgery and intradural changes caused by trauma or bleeding, are recog- nized as the main causes. 10-14 Of cases, 86% are located in the lumbar region 9 ; however, because of an increasing number of Key words - Arachnoiditis - Dural inflammation - Lumbar epidural abscess - Surgical treatment Abbreviations and Acronyms CRP: C-reactive protein CSF: Cerebrospinal fluid MRI: Magnetic resonance imaging SAA: Spinal adhesive arachnoiditis From the Departments of 1 Neurosurgery, 2 Trauma, Hand and Reconstructive Surgery, and 3 Pediatric Surgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany To whom correspondence should be addressed: Theresa Krätzig, M.D. [E-mail: t.kraetzig@uke.de] Citation: World Neurosurg. (2018). https://doi.org/10.1016/j.wneu.2018.05.219 Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2018 Elsevier Inc. All rights reserved. WORLD NEUROSURGERY -: e1-e10, - 2018 www.WORLDNEUROSURGERY.org e1 Original Article