Portovertebral shunts play an important role in most of the genesis of spinal lesions in hydatid cysts. The vertebral body is generally the first target. When echinococcal larvae are carried to a vertebral body, the parasite grows multilocularly along the bony intratrabecular space and infiltrates and destroys the bone like a tumour, because of a lack of defensive reaction of the bony tissue (Işlekel et al. 1998). Pathological fractures occur due to compression or avascular necrosis of the cortical bone. Subsequently the disease usually spreads to the pedicles, laminae or the ribs. The intervertebral discs are spared in the early stages of the disease. Finally the infestation may extend beyond the vertebral body and periosteum with the development of a cyst with space-occupying symptomatology. It was observed that hydrophilic degeneration of the Echinococcus embryo without reactive osteitis could develop over a number of years, with damage and erosion of the trabecular composition of the bone by the expanding vesicles, with subsequent cystic progression and invasion of all vertebral structures (Tsitouridis and Dimitriadis 1997). When the cyst perforates the cortex, it extends to the paravertebral structures and into the spinal canal or neural foramina (Kalkan et al. 2008). Bone destruction and puslike fluid may be encountered during operation, leading to the name ‘ossifluent abscess’ (Pamir et al. 2002). Papanikolaou (2008) described three mechanisms for the intraosseous invasion as mechanical, ischaemic and cellular process. The mechanical process affects the surrounding tissues by expansion, compression, dislocation and repression which cause bone and nerve tissue atrophy and osteitis. The ischaemic process affects the nutrient vessels by obstruction and compression which cause bone necrosis and sequestra formation. The cellular process affects the bone tissue by osteoclast proliferation and causes destruction.

The pathology of spinal hydatidosis has been discussed in detail in Chap. 9.

Surgery is currently the mainstay treatment modality for spinal hydatidosis. The first surgical intervention in spinal hydatidosis was reported in 1819 by (Reydellet 1819; Rayport et al. 1964). Most of the cases admitted to surgeons with spinal cord compression syndrome symptomatology are urgent surgeries (Pamir et al. 2002). Patients with spinal hydatid disease usually present with a long history of back pain or other non-specific symptoms of spinal cord compression. Weakness of the limbs occurs in the later stages. Paraplegia or radicular compression is said to occur in 25–84 % of patients (Baysefer et al. 1996). Preoperative diagnosis and the real extent of the disease are very important for operative planning. Preoperative diagnosis of the lesion guides the surgical preference. The correct diagnosis, natural history and serological and radiological studies are essential (Kalkan et al. 2008). Generally, routine laboratory tests do not show specific values. Eosinophilia is mostly limited (15 %) or absent. An intradermal Casoni test result is positive in 95 %, but there are up to 40 % false-positive results. Indirect haemagglutination test and enzyme-linked immunosorbent assay are established methods for the detection of anti-Echinococcus antibodies (immunoglobulin G). Serological tests are 80–100 % sensitive and 88–96 % specific for liver hydatid disease. They have 50–56 % sensitivity for lung disease and only 25–56 % for other organs like spinal cyst hydatid (El-On et al. 2003; Thaler et al. 2010).

Successful treatment of the spinal hydatidosis is challenging because of its invasiveness and its potentially severe complications. Surgical excision is the first and most effective option. The total eradication of the cyst without rupture should be the primary goal of the surgery (Thaler et al. 2010). In clinical practice, however, this is not possible in the spine because there is no one cyst but a multitude of small cysts. Either anterior or posterior approaches can be preferred for the surgical treatment. Pure intradurally or epidurally located lesions at all spinal levels are approached posteriorly. In these cases surgical excision without intraoperative rupture results in cure (Pamir et al. 2002). Bone involvement is very important for defining the recurrence rates. Surgical planning should be made according to this.

Spinal disease most frequently involves the thoracic segments (46–50 %). Lumbar segments (20–29 %) and sacral segments (20–23 %) are also involved frequently. Cervical spine is the least common affected segment (Pamir et al. 2002). Twenty-eight reports of spinal hydatid disease, published during the past five decades, from Turkey, were reviewed, and 71 patients with spinal hydatid disease were collected (Turgut 1997). According to this study, spinal echinococcus involved the thoracic segment of the spine in 35 patients (49 %), the lumbar segment in 28 patients (39 %), the cervical segment in three patients (4 %), the thoracolumbar segment in three patients (4 %) and the sacral segment in one patient (2 %) (Turgut 1997). One patient had non-contagious lesions in the cervical and lumbar segments (Turgut 1997).