Anterior Lumbar Spinal Fusion
Who Needs It?
This operation is performed for back pain, when this is found to be coming from a disc rather than the other areas in the spine, such as the nerve roots or joints. This can be difficult to determine and may require careful investigation with MRI scanning and discography. The aim of the operation is to fuse the vertebra above to the vertebra below the affected disc. This may be done at one or two levels (discs and neighbouring vertebrae) as required and as determined by the investigations.
The Operation
This is performed under anaesthetic (general), with the patient lying on their back. The spine is approached from the front, through the abdomen. This is achieved using a retro-peritoneal approach, thereby avoiding contact with the bowel altogether. The spine is then visualised and the blood vessels over it, the aorta and the vena cava can be gently retracted to gain access to the spine and, specifically the discs.
Virtually the whole disc can then be removed and the spinal alignment can be restored using a series of distraction plugs in the disc space. The bones can then be fixed in position using a variety of devices - our favoured one is an interbody fusion cage, which locks the bones together and allows them to heal whilst maintaining the alignment of the spine.
Recovery
This is usually rapid because the level of pain the patient experienced from the bad disc is significantly reduced post-operatively. However, the bones do need to heal and this may take several weeks or even months. To allow this to happen the patient must avoid excessive bending, lifting or exercising, other than in-line exercises such as walking, and may need to wear a corset or a plastic moulded brace, depending upon the extent of and findings at surgery.
Patients who work in a sedentary occupation, who are able to stand, stretch and walk around from time to time, are usually able to return to work after 4 - 6 weeks. Manual workers may need to refrain from work for up to 3 -4 months.
Follow-Up
Clinic visits are routinely performed at 6 weeks and then at 3, 6 and 12 months post-operatively. X-rays are taken on each occasion to ensure that the bones are fusing (healing) and that the spinal alignment maintained has been maintained.
Outcome of Surgery
Patients are rarely rendered pain free by this type of surgery. It does, however, rid the patients of the severe exacerbations of their pain and prevent the pain on coughing, sneezing, bending etc. Patients are therefore much more able to live normally and rely less on outside help.
The success rate can be measured in terms of successful fusion or success in terms of pain relief. The success rate of fusion in our unit is around 90 %, but the success rate in terms of obtaining good pain relief is lower. This is because the operation only tackles the pain coming from the disc and the other elements of the spine may be contributing to the symptoms, a feature which can be difficult to elucidate pre-operatively.
What are the risks of this operation?
| Risk | Cause |
% Risk (note figures vary) |
| Nerve injury/paralysis | Damage to the nerve whilst removing disc/bone or inserting fusion devices | <1 |
| Fluid leak | Small tear in the nerve sheath allowing leakage of cerebrospinal fluid | <1 (But higher if previous surgery |
| Infection | Contamination during surgery or, rarely, late infection via the blood | Approx 1 |
| Back pain | Some patients will develop back pain due to the stretching of the spine | Transient and dependent upon fitness |
| Adjacent disc damage | The stiffening effect of the fusion puts more pressure on the disc above (or below) | 4 - 12% (some papers say higher) |
| Failure of fusion | If the bone graft does not heal, the pain may return | Up to 30%, depending on technique used |
| Bowel injury | Bowel is retracted during surgery | <1 |
| Bladder/ureter injury | Structures are retracted during surgery | <1 |
| Impotence | Retraction or injury to a small nerve in front of the spine leads to retrograde ejaculation in men | Approx 1 with the retro-peritoneal approach |
| Warm leg | The sympathetic nerve runs alongside the lumbar discs. If damaged the left leg (usually) will feel warmer for some months after the operation | 1 - 5 (but higher if previous surgery |
| Wound pain | Surgery | All to some extent |
To see pictures of this procedure visit the picture gallery