2 The condition, current treatments and procedure
2.1 Chronic low back pain may result from degenerative changes in the intervertebral discs or spinal facet joints.
2.2 Conservative treatments include pain relief, non steroidal anti-inflammatory medication and manual therapy (see NICE's guideline on low back pain and sciatica). For people with severe, lifestyle-limiting, chronic low back pain that does not respond to conservative treatments, surgery may be appropriate. This may include bony fusion of vertebrae (to immobilise segments of the vertebral column thought to be responsible for back pain, using either a posterior or anterior approach) or inserting a prosthetic intervertebral disc (which preserves lumbar mobility to reduce the risk of degenerative changes in adjacent intervertebral disc spaces). Other surgical alternatives include non‑rigid stabilisation techniques.
2.3 Transaxial interbody lumbosacral fusion is done with the patient under general anaesthesia. A small incision is made lateral to the coccyx and a guide-pin introducer is inserted under fluoroscopic guidance. Air insufflation may be used to improve visualisation of the rectum during fluoroscopy. The guide-pin introducer is advanced over the sacrum's midline anterior surface towards the L5–S1 space. A reamer is then passed over the guidewire to the endplate of S1. As with conventional spinal fusion, the disc is removed through the canal created by the reamer. A mixture typically consisting of commercially available bone graft material, patient's own bone extracted from the surgical site and blood is prepared in the operating theatre and injected into the disc space. A special rod is screwed between the L5 and S1 vertebrae along the canal created by the reamer to maintain segmental height and alignment. Using a posterior approach, pedicle or facet joint screws may be used to provide extra stabilisation.
2.4 The potential benefits of the transaxial approach include faster recovery and less postoperative morbidity compared with conventional spinal fusion surgery.