Spinal Laxity, Hypermobility and Instability A Surgeon’s View Christian Ulbricht Consultant Spinal Neurosurgeon Imperial College Healthcare NHS Trust

Understanding the patient Understanding the pathophysiology / mechanical problems Surgical options

Key Issues Complex needs / multiple complaints What is causing the pain? Surgeons only have options for segmental problems

Case ? Anterior spinal cord herniation

Clinical Hypermobility in the spine

Undetected Neural Compromise / Instability Flexion / extension MRI Francis W. Smith MD. FRCR, FRCS, FRCP, FFSEM(UK). Clinical Director, Medserena U.K. Clinical Professor of Radiology, University of Aberdeen. Professor of Health & Sport Science, The Robert Gordon University.

Fluctuating spinal stenosis Erect Supine Fluctuating spinal stenosis Erect Sit Flexion Sit Neutral Sit Extension Curtesy of Prof Francis W. Smith MD

Sit Flexion Sit Neutral Sit Extension Curtesy of Prof Francis W. Smith MD

CERVICAL SPINE ANGLE Curtesy of Prof Francis W. Smith MD

CERVICAL SPINE ANGLE Normal/Control E.D.S. Neutral 17.1o 17.7o Flexion 11.5o 18.1o Extension 32.1o 50.1o Curtesy of Prof Francis W. Smith MD

Upright / dynamic MRI UPpright Recumbent Curtesy of Prof Francis W. Smith MD

Curtesy of Prof Francis W. Smith MD S N

Specific views to assess the atlanto-axial joint Normal alignment 20o of dislocation at the atlanto-axial joint Curtesy of Prof Francis W. Smith MD

Clivo-vertebral or Clivo-axial angle (normal range 150°-180°). Curtesy of Prof Francis W. Smith MD

(The basion axial interval is the length of a line drawn between the tip of the basion and a line drawn along the posterior aspect of the odontoid peg. The basion dental interval is a distance measured between the tip of the basion and the tip of the dens. Both these measurements should be less than 12 mm. If they are greater than 12 mm, then occipito-atlantal disassociation has occurred. These measurements are often referred to as "The rule of 12") (The Grabb-Oakes measurement is the perpendicular distance from the BpC2 line [Basion to posterior inferior C2 body] to the dura. A value greater than or equal to 9 mm indicates ventral brainstem compression)

Cranio-cervical junction Cervico-Medullary-Syndrome Headache, sub-occipital or neck pain Diplopia , decreased or blurred vision Dizziness, vertigo, imbalance Tinnitus or decreased hearing Dysautonomia, POTS, syncope or pre-syncope Dysarthria, dysphagia, choking Altered breathing and sleep architecture Weakness, clumsiness, spasticity, Paraesthesia, dysesthesia Gait changes, Urinary urgency or frequency

Pathophysiology of cord / medulla compression Neural stretch injury causes apoptosis and cell death

Surgical Targets for Hypermobility Compromise of neural structures Segmental instability causing pain ? Prophylactic surgery Trial brace before surgery Main decision : risks vs benefits

Decompression Fixation ? Dynamic stabilisation Surgical Options Decompression Fixation ? Dynamic stabilisation

Dynamic stabilisation Surgical Options Dynamic stabilisation Flexible rod system (Dynesis), Percudyn

Surgical Options Fixation Simple single level vs complex multilevel / cranio-cervical No options for thoracic spine Lumbar fixation

Surgical Options Decompression Limited indication for decompression only in EDS patients Usually combined with fixation Roots vs cord/ cauda equina

Risks vs Benefit Risks Immediate: infection, nerve / spinal cord damage, vascular injury, implant malpositioning Delayed: no improvement, loosening of implants, adjacent segment disease

Conclusions Complex patients Key is understanding of patient needs and identifying segmental pathology Difficult balance of risks / benefits Surgery only for clear indications