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Chronic adhesive arachnoiditis with spinal cord dysfunction


Introduction

Arachnoiditis is an inflammatory condition of the arachnoid mater, leading to thickened leptomeninges and neurological symptoms in many cases. Ninety percent of patients with arachnoiditis experience a burning type pain. The most common location of spinal arachnoiditis is the thoracic segment. The known causes include idiopathic, iatrogenic, foreign bodies (intrathecal pain pumps, radiographic contrast), subarachnoid hemorrhage, and infection. Overall, spine surgery is the most common condition associated with arachnoiditis. Spinal arachnoiditis can manifest as meningeal thickening, adhesions with cord deformity, meningeal enhancement, arachnoid cyst formation, and syrinx. Chronic adhesive arachnoiditis can result from prolonged irritation of the arachnoid and lead to spinal cord or nerve root tethering. Spinal cord dysfunction and progressive syringomyelia can also occur as a result of this syndrome. In turn, spinal arachnoid cysts can cause progressive compressive myelopathy. The evaluation and diagnosis of arachnoiditis can be made with magnetic resonance imaging (MRI) or myelography, which will typically demonstrate loculations of cerebrospinal fluid in one or multiple locations. Increased T2 signal change within the cord can also be seen in severe cases with tethering. The main goal of arachnoiditis treatment is pain relief. Heterogeneous results have been reported for conservative and surgical modalities. Despite this, surgery remains a treatment option for this condition. In this chapter, we discuss the case of a young patient with a history of meningitis who presented with progressive left hemiparesis.

Example case

  • Chief complaint : new weakness

  • History of present illness : This is a 21-year-old male patient with a history of a seizure disorder and developmental delay due to meningitis during childhood, who presented with worsening left upper and lower extremity weakness. His mother states that he has been having increased difficulty ambulating and feeding himself over the last month. He has also been experiencing urinary incontinence. The patient underwent a magnetic resonance imaging (MRI) of the cervical and thoracic spine that demonstrated the presence of an anterior intradural arachnoid cyst spanning the cervical and thoracic spine ( Fig. 70.1 ).

    Fig. 70.1, Preoperative magnetic resonance imaging (MRI) of the cervical and thoracic spine. (A) Sagittal T2 image demonstrating the presence of a large abnormal intradural extramedullary fluid collection compatible with arachnoid cyst, where the cystic collection extends from the foramen magnum and continues enlarging caudally within the cervical and upper thoracic spine. (B) Sagittal T2 image demonstrating an arachnoid cyst spanning the entire thoracic spine, with loculations within the collection, most prominent at T4-T6 levels. Cerebrospinal fluid (CSF) intensity within the cyst is slightly brighter than the normal CSF. (C) Axial T2 image demonstrating the abnormal intradural extramedullary fluid collection ventral to the cervical and thoracic spinal cord with significant compression of the neural tissue.

  • Medications : Vimpat, Keppra

  • Allergies : no known drug allergies

  • Past medical and surgical history : coccidioidal meningitis, right hemispheric stroke, hydrocephalus, ventriculoperitoneal shunt placement.

  • Family history : none

  • Social history : lives with mother, dependent for activities of daily living

  • Physical examination : awake, alert, and oriented to person, place, and time; cranial nerves II–XII intact; right deltoids/triceps/biceps 5/5; interossei 5/5; iliopsoas/knee flexion/knee extension/dorsi, and plantar flexion 5/5. Left deltoids/triceps/biceps 3/5; interossei 3/5; iliopsoas/knee, flexion/knee, extension/dorsi, and plantar flexion 3/5

  • Reflexes : 3+ in bilateral biceps/triceps/brachioradialis with positive Hoffman; 3+ in bilateral patella/ankle; no clonus or Babinski; sensation normal on left hemibody

  • Adrian Casey, MD

  • Neurosurgery

  • National Hospital for Neurology and Neurosurgery

  • Queen Square, Holborn, London, United Kingdom

  • Patrick C. Hsieh, MD

  • Neurosurgery

  • University of Southern California

  • Los Angeles, California, United States

  • Daniel C. Liu, MD, PhD

  • Neurosurgery

  • University of California at Los Angeles

  • Los Angeles, California, United States

  • Claudio Yampolsky, MD

  • Neurosurgery

  • Hospital Italiano de Buenos Aires

  • Buenos Aires, Argentina

Preoperative
Additional tests requested

  • MRI brain and complete spine with CISS

  • CT C-T spine

  • Anesthesiology evaluation

  • +/- Mental capacity assessment

  • CT myelogram complete spine

  • CSF studies

  • CT myelogram complete spine

  • Interventional myelogram if T myelogram insufficient

  • MRI brain

  • Neurology evaluation

  • SSEP

  • MRI brain with cine imaging

Surgical approach selected T1–2 laminectomy for arachnoid cyst fenestration and lysis of adhesions (+/- shunt) C6-T6 laminectomy for arachnoid cyst fenestration, possible extension to C3 C6-T6 laminectomy for lysis of adhesion If flow obstruction present on imaging with medullary compression, T1–2 laminectomy and placement of arachnoid cyst-subarachnoid shunt
Goal of surgery Spinal cord decompression, arachnoid cyst fenestration, open CSF pathways Spinal cord decompression, excision of arachnoid cyst, minimize cyst recurrence Lysis of adhesions, reduce mass effect Medullary decompression, cyst drainage
Perioperative
Positioning Prone, with Mayfield pins Prone on Jackson table, with Mayfield pins Prone, with Mayfield pins Prone
Surgical equipment

  • IOM

  • Fluoroscopy

  • Surgical microscope

  • +/- Ultrasound

  • Lumbar drain

  • IOM (MEP/SSEP)

  • Fluoroscopy

  • O-arm

  • Ultrasound

  • IOM (MEP/SSEP)

  • Fluoroscopy

  • Surgical microscope

  • Lumbar drain

  • IOM

  • Fluoroscopy

  • Surgical navigation

  • Surgical microscope

Medications Steroids, maintain MAP Steroids, MAP 85 Fluorescein None
Anatomical considerations Spinal cord, facet joints Spinal cord, dentate ligaments, segmental nerves, anterior spinal artery Spinal cord, vertebral arteries Lamina, dentate ligaments, dura, medulla
Complications feared with approach chosen CSF leak, progressive neurological decline, recurrent arachnoiditis or arachnoid cyst Spinal cord injury, CSF leak Spinal cord injury, spinal instability CSF fistula, infection, neurological deficit
Intraoperative
Anesthesia General General General General
Exposure T1-2 C6-T6 C6-T6 T1-2
Levels decompressed T1-2 C6-T6 C6-T6 T1-2
Levels fused None None If needed None
Surgical narrative Position prone, x-ray level check, midline incision high thoracic spine, subperiosteal muscle strip to expose T1–2 laminae, laminectomy with high-speed drill, x-ray to confirm level, ultrasound to check location for cyst, midline durotomy and lateral suspension of dura under microscope, identification of cyst and drainage, section dentate ligament if needed, consider shunt, check for cord decompression proximally and distally, dural closure with clips and dural substitute with glue, layered closure Position prone, baseline MEP/SSEP, expose from C6-T6, confirm levels with fluoroscopy, C6-T6 laminectomy without facet violation, open dura under microscopic visualization, examine spinal cord/ nerves/dentate ligaments, release all arachnoid adhesions, ultrasound to visualize size and contour of arachnoid cyst to spinal cord relationship, cut dentate ligaments bilaterally between segment nerves from C6 to T6, place 6-0 Prolene stitch on medial end of cut dentate ligament, gently rotate spinal cord to examine ventral subarachnoid space, identify cyst wall and excise cyst wall, check for decompression and deflation of cyst with ultrasound, watertight dural closure, dural substitute onlay and tissel over dural closure site, drain placement in epidural space, intraoperative topic vancomycin and tobramycin, wound closure in layers Preflip IOM, position prone, mark midline incision based on x-ray, midline posterior incision, dissect to posterior elements in avascular plane, drill bilateral troughs at cervical level overlying arachnoid cyst, separate ligamentum flavum with Kerrison rongeurs and lift lamina from dura in one piece, drill out thoracic lamina if noncommunicating arachnoid cyst extends into thoracic level, midline longitudinal durotomy and retract dural leaflets, identify isolated arachnoid cysts under microscopic visualization and fluorescein injection as needed, minimize spinal cord manipulation, expand laminectomies as needed, lyse arachnoid cysts with sharp dissection and bipolar cauterization, verify communication with the subarachnoid space using fluorescein, confirm stability/improvement with IOMN, primary dural closure with dural sealant, fusion if needed, layered closure with subfascial drain to gravity, vancomycin epifascially Position prone, midline incision at T1–2 level, left-side laminectomy, placement of minimally invasive tubular retractor, dural opening, dissection of dentate ligament, mobilization with continuous IOM, drain collection, placement catheter and connect to subarachnoid space, layered closure
Complication avoidance Limit exposure T1–2, ultrasound to confirm location of cyst, section dentate ligament if needed, consider shunt Avoid facet violation, ultrasound to better delineate relationship between arachnoid cyst and spinal cord, release dentate ligaments, manipulate cord by stitching cut dentate ligament, ultrasound to evaluate decompression Preflip IOM, en bloc laminectomy, fluorescein to help identify arachnoid cyst, minimize spinal cord manipulation, verify communication with the subarachnoid space using fluorescein Hemilaminectomy, cut dentate ligament, cyst-subarachnoid shunt
Postoperative
Admission High dependency unit ICU Floor Floor
Postoperative complications feared CSF leak, meningitis, spinal cord injury, recurrence, adhesions New neurological deficit, CSF leak, hematoma, recurrence of cyst, cord compression CSF leak, recurrence of adhesions CSF leak, infection, neurological deficit
Anticipated length of stay 5–7 days 4–5 days 2–5 days 2 days
Follow-up testing MRI prior to discharge, 3 months after surgery MRI before discharge, 3 months after surgery CT myelogram 3 months after surgery MRI within 48 hours of surgery
Bracing None None Hard collar None
Follow-up visits 6 weeks, 3 months, 6 months, 12 months after surgery 2–3 weeks, 6 weeks, 3 months, 6 months, 12 months, then annually after surgery 2 weeks, 6 weeks, 3 months after surgery 7 days, 2 weeks, 4 weeks after surgery
CISS , constructive interference in steady state; CSF , cerebrospinal fluid; CT , computed tomography; ICU , intensive care unit; IOM , intraoperative monitoring; MAP , mean arterial pressure; MEP , motor evoked potential, MRI , magnetic resonance imaging; SSEP , somatosensory evoked potential.

Differential diagnosis

  • ▪

    Arachnoiditis

  • ▪

    Meningitis

  • ▪

    Intramedullary spinal cord tumor

  • ▪

    Congenital arachnoid cysts

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