Retethering in EhlersDanlos S de Ribaupierre Toronto November

Re-tethering in Ehlers-Danlos S de Ribaupierre Toronto, November 4 th 2017

CFPC Co. I Templates: Slide 2 FACULTY/PRESENTER DISCLOSURE • Faculty: Sandrine de Ribaupierre • Relationships with commercial interests: - Grants/Research Support: CIHR, Brains. CAN (topics not related) - Speakers Bureau/Honoraria: None - Consulting Fees: None - Other: Member of the London Neurosurgery Practice Group

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Case report • Active woman in her 30 s presented with increasing weakness of left quadriceps and hamstring; numbness of perianal and buttocks on the L; absent L Achilles • MRI showed fatty filum and conus at L 5 level • Operated with full recovery

Con’t • 5 years later • Episodes of L leg numbness and fluctuation of motor function of foot. • Repeat MRI – Conus now around L 3 -L 4

Con’t • Because of symptomatology worsening and radiological evidences • Re-operated –> OR findings: few arachnoiditis bands, no real scar • Released with return to baseline • Diagnosed with EDS

Tethered cord • Filum terminale: viscoelastic band connecting the conus medullaris with the dural sac at the S 2 level ~20 cm – Contains glial and ependymal cells • Filum terminale internum (intradural upper component) • Filum terminale externum (lower extradural component) • Function? Stabilize, and buffer distal cord from cephalic and caudal tractions • Presence of fat within filum interferes with normal cord ascension and causes traction -> tethering – Histological findings in tethered cords: fatty tissue, vascular lacunes, dyplastic axons From Saker, J of Clinical Neuroscience, 2017

Embryology • Neurulation: Day 18 -27 – Formation of the neural grove – Closure of neural tube

Embryology • Secondary Neurulation (Canalization of tail bud) : Day 28 -50 – Formation of vacuoles within ectodermal cell mass -> central canal – Formation of lower lumbar, sacral and coccygeal segments

Embryology • Regression of caudal neural tube Day 52 -> – Formation of the filum

Symptoms of tethered cord • Lower back pain • Neurogenic bladder (frequency, urgency irregular urinary stream), UTI, incontinence or retention • Lower extremities sensory or motor changes, often asymmetrical • Tightness of legs and cramps • Scoliosis, kypho-lordosis • Feet/leg deformities, asymmetries (in children) • Bowel incontinence or constipation

Imaging • Low lying conus (below L 2) • Fatty infiltration • Controversy of “upright” or “lying” MRI – prone MRI to see tethering/re-tethering [Sing 2012] – Level of the conus seems to have the highest inter -reader concordance and diagnostic accuracy

Tethered cord in EDS Etiology? Embryological In relation with EDS? Embryological? Changes in collagen, therefore thickened filum Inflammatory? Findings in operated filums

Incidence? ? ? • In general population? In children 0. 1% [Turkish study – Bademci 2006] • Reviewed literature of tethered cord in adult to look for EDS – > 500 cases 1940 -2015, no mention of EDS in any review/case report – Probably some cases but nobody has thought of 1) reporting it or 2) not even diagnosed • Report to Ontario Ministry in 2015 – 3 adult tethered cords operated cases in 3 years, and 5 out of province request…

Tethered cord in EDS • Histological findings (under a microscope…): – Abnormal clusters of inflammation: Neutrophils and macrophages in filum in EDS – Disruption of elastin fibers – Decrease of ratio in elastin/collagen fibers – Activated Mastcells seen in the filum

Results from untethering • Improvement in adults without EDS: – Improvement of pain 75 -85% – Improvement of motor weakness: 52 -61% – Improvement of sensory deficit: 40 -50% In patients with EDS: F. Henderson, EDNF Baltimore 2015

Re-tethering • Recurring symptomatology after a first surgery (but needs to have improved in between) • Most likely due to scar tissue, or sometimes dual filum not identified • Incidence: 2. 7 - 8. 6% (5 studies > 800 patients overall – Yong 2011, Samuels 2009, Ogiwara 2011, Vassilyadi 2012, Geyik 2015) • For comparison 33% in complex etiologies (lipomyelomeningocele, myelomeningocele) [Samuels 2009] • Incidence in EDS: Unknown

How do you investigate? • Clinically – – Neurosurgeon Neurologist (EMG when symptomatology unclear) Urologist (urodynamic studies) Genetics • Support team: ideally – – Nurse practitioner Physiotherapist Pain Management Social work • Radiologically (cine. MRI? , supine MRI? , prone MRI) – Increased difficulty by previous surgery

Un-answered questions: • Is the incidence of tethering/retethering higher in EDS? – No true incidence in literature – If yes one possible reason might be linked to inflammation – Should we change our operative approach? • Is surgery the only option if the etiology of tethering is inflammatory?

Conclusions • In patient with symptoms of tethered cord with other EDS symptoms, investigate for EDS • Minimalize surgical approach in patient with EDS as scarring might be more complex • Need of a multidisciplinary team to take care of patients • Needs for multicentric studies and population studies to answer questions

Questions?

• Incidental fat within the filum terminale is found in up to 17% of normal adults, frequently seen on routine magnetic resonance imaging (MRI) of the lumbosacral spine [Mc. Lendon 1988]

• F. Henderson survey – 84 surveys of patient operated for tethered cord – 30 responders and all EDS