Lumbar TDA appeared as efficient in long-term pain alleviation, consequent reduction of pain medication consumption and improvement of quality of life. The procedure also appeared sufficiently safe, but surgeons have to be aware of a list of potential adverse events. The outcome is stable over the 5-year postoperative period. The vast majority of treated segments remained mobile after 5 years, although almost half of patients showed osteophytes.

Cervical TDA appeared as safe and efficient in long-term pain alleviation, consequent reduction of pain killer consumption and in improvement of quality of life. The improvement is stable over the 5 years postoperative period. The vast majority of treated segments remained mobile after 5 years, although 40.7 % of patients showed osteophytes.

Remote cerebellar haemorrhage (RCH) is a well-described complication of supratentorial surgical procedures with an incidence ranging between 0.2 and 4.9 %, but is a rare complication of spinal surgery. We report a case of RCH in a 65-year-old woman who showed sudden mental deterioration 48 h after lumbar spinal surgery, which was complicated by incidental dural tearing with minimal CSF loss. Brain CT scan revealed hypodense areas compatible with acute infarction involving mostly the left cerebellar hemisphere. No cerebral bleeding was observed. MRI was also performed revealing small cerebellar areas of acute infarction mainly relating the vermis and the left postero-inferior cerebellar hemisphere with haemorrhagic transformation and mass effect in the posterior fossa producing acute hydrocephalus. Haematoma removal was initially attempted by means of a suboccipital craniotomy. An external ventricular derivation was placed in a second procedure 24 h later due to the persistence of ventricular dilatation. At discharge the patient was only showing a slight dysmetria with the fine motor skills of hands and fingers. All cases of RCH after spinal surgery reported in the literature are invariably associated to iatrogenic dural tearing; although CSF loss seems to play the key role in the pathogenesis of this rare complication, the exact pathophysiology of this condition still remains undetermined.

Our data indicate poor correlation between clinical outcome and position of the prosthesis. Although 48 % of the implants were suboptimally placed in either the coronal or sagittal plane, most of the patients reached a very good clinical outcome. However, suboptimally placed devices appeared to cause significantly more neurological symptoms in long-term follow-up.

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