Instability criteria for cervical surgery. The lower cervical spine Rapanà UOC Neurochirurgia Ospedale “L. Bonomo” – Andria (BT)

Subaxial cervical spine trauma ….Subaxial spine injuries accounts for the majority of cervical traumatic lesions. About 65% of fractures and more than 75% of all dislocations. Vaccaro, Spine 2007

Cervical spine Biomechanic Because of the orientation of the cervical spine facet joints, the cervical spine is designed for a great deal of mobility, but it lacks stability

Cervical traumas ?

Neuroradiological assessment - results Cervical spine Neuroradiological assessment - results Plan X-ray AP, LL, obliques, dinamiche Cord compression CT scan Vertebral instability MR T1, T2, STIR….

Surgical treatment - indications Cervical trauma Surgical treatment - indications Cord compression

Surgical treatment - indications Cervical trauma Surgical treatment - indications ….In the cases of traumatic cervical spine fractures and cervical facet dislocation injuries, narrowing of the spinal canal caused by displacement of fracture fragments or subluxation of a vertebra frequently produces spinal cord injury. Reduction of the dislocation deformity helps to restore spinal alignment and the diameter of the bony canal by eliminating bony compression of the spinal cord….

Traumi cervicali Cervical trauma Trattamento chirurgico - indicazioni Surgical treatment - indications Traumi cervicali Trattamento chirurgico - indicazioni Vertebral instability “…l’instabilità vertebrale è l’incapacità da parte della colonna stessa a mantenere invariati i rapporti tra i suoi elementi sotto carichi fisiologici sì da impedire la lesione nervosa..” White & Panjabi, 1978

Cervical spine trauma Instability The amount of normal cervical motion at each level has been extensively described, and this knowledge can be important in assessing spinal stability after treatment. Flexion-extension motion is about 20 degrees (greatest at the C4-5 and C5-6); Axial rotation ranges from 2 to 7 degrees at each of the subaxial motion segments; Lateral flexion is 10 to 11 degrees per level in the upper segments (C2-5) and decreases caudally, with only 2 degrees observed at the cervicothoracic junction. Radiographic indications of instability. Greater than 3.5 mm of translation (A) or 11 degrees of angulation (B) and widening of the separation between spinous processes are indications of instability on the lateral plain film. Stress flexion/extension radiographs rarely if ever should be performed if instability is suspected; they should be performed in the awake and alert patient only. In a patient with neck pain, they are best delayed until spasm has subsided, which can mask instability. 

Classification criteria A scheme for the classification of lower cervical spine injuries C. ARGENSON Techniques Chirurgicales EMC Orth. Traumat., 1994 Classification criteria Forces (A,B,C) Strenght (I,II,III)

Conservative treatment Strenght (I, II, III) Conservative treatment

Anterior approach (or posterior) strenght (I, II, III) Anterior approach (or posterior)

Somatectomia e plating

Strenght (I, II, III) Combined approach

Stabilizzazione 360° C6-C7 Follow-up 11 anni

What about the neurological status???? A scheme for the classification of lower cervical spine injuries C. ARGENSON Techniques Chirurgicales EMC Orth. Traumat., 1994 Morphological classification Spinal Instability is deduced What about the neurological status????

Disco ligamentous complex: Ligamentous integrity is directly proprtional to spinal stability. Ligamentuos healing is less predicatble than bony healing Neurological status: as nerve roots and spinal cord are well protected from trauma, their compromission is an important indicator of severety of spinal column injury

Disco ligamentous complex: Injury morphology: Compression: a visible loss of height or disruption of an handplate Distraction: evidence of anatomical dissociation of vertical axis Translation/rotation: horizontal displacement of one element with respect to the other. In dynamic study translation >3.5 mm or 11° is pathologic Disco ligamentous complex: Intervertebral disc, ALL, PLL, yellow ligaments, interspinous and supraspinous ligaments, facet capsules Discoligamentous injuries is appreciated by indirect means (eg: abnormal bony relationship….) Neurological status: Incomplete cord injury requires more urgent treatment Persistence of cord compression receives one more point Punteggio 0-3: conservativo Punteggio 4: conservativo/chirurgico Punteggio >5: chirurgico

43 years old ♂; car accident; neurological examination: paraplegia with severe diparesis

Delayed or missed diagnosis of cervical spine injuries Patrick Platzer MD*, Nicole Hauswirth MD*, Manuela Jaindl MD, Sheila Chatwani MD, Vilmos Vecsei MD, Christian Gaebler MD J Trauma 2006 Jul;61(1):150-5 “…The results of this retrospective study show an incidence of delayed diagnosis of 4.9%. Comparing to previous studies, the incidence rate at this trauma unit was relatively low, but the causes for delays in diagnosis appear not to have changed in the last ten to fifteen years…”. Traumi maggiori e/o pericolo di vita Errato/incompleto inquadramento clinico Studio radiografico incompleto Studio radiografico inadeguato (giunzione cranio-cervicale e cervico-dorsale, dorsale superiore) Errore interpretativo Satisfaction of search phenomenon* * Rischio di “seconda frattura”: 5-15%

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