Over 10 years results have been achieved with use of the lumbar disc since 2002 and the cervical disc since 2003. Surgery is considered if symptoms persist or deteriorate despite ongoing conservative management.

Indications for surgery

Relative – there is no major neurological problem but the patient, after exhaustion of conservative options, can no longer tolerate the symptoms.

Absolute – severe neurological problems develop and/or a marked deterioration in stability occurs. Neurological problems include weakness, loss of sensation and loss of bladder and/or anal sphincter function.

Surgical techniques


The removal of a prolapsed (slipped) disc using magnification techniques. The advantage of this approach is minimal invasiveness and quick recovery. It works best at the level L5/S1. At other levels however, especially at L4/L5, a recurrent disc prolapse may occur.

Decompressive surgery

This is directed at the relief of a compressed spinal canal and/or involved nerve roots. The approach is via a laminectomy (removal of part of the vertebra) if done from behind or vertebrectomy from in front.

Discectomy and/or decompression and fusion

Following a discectomy (the removal of all or part of an intervertebral disc), a fusion may be performed to either prevent a recurrent prolapse or treat associated mechanical instability. A fusion may be performed from anterior (in front) or posterior (behind). Various cages or plates are used for anterior work while pedicular screws and rods are used for posterior work (titanium alloys).

Disc replacement surgery

This is done from anterior in the lumbar or cervical spine. In this way, the disc is removed and replaced with a fully articulating prosthesis. This maintains the movement between the vertebrae and is aimed at preventing the excessive degeneration of the levels above and below the involved level(s).

The latter problem occurs with fusion surgery. In addition, it restores the anatomical curvature in the relevant spinal segment(s).

Dr Ulrich Hähnle is the co-developer of the Kineflex disc prosthesis, which is a popular artificial disc in South Africa. (See below for more information.)

Other motion-preserving surgery

Nucleus replacement: only the inner part of the disc nucleus is replaced by a “soft disc”. The indications for this procedure are very limited.

Posterior motion restricting procedures: The indications for this procedure are limited.


The Kineflex disc prosthesis was originally named “Centurion disc”as it was developed in Centurion, South Africa. The main objectives in the development of this prosthesis was an un/semi-constrained, but re-centering mechanism. This is done to facilitate reliable midline and posterior placement of the implant within the disc space in severely degenerative disc spaces. As well as to develop a simple, safe implantation technique with the implantation being executed through a minimal invasive approach.

View a flash animation of the Kineflex in action
Source: Motion Preservation Surgery of the Spine: Advanced Techniques and Controversies

Key Points

  • The Kineflex disc is a re-centering, unconstrained, metal on metal mechanical disc prosthesis
  • A cervical and a lumbar disc are currently CE certified and are also being evaluated in USA FDA PMA randomised, controlled trials
  • The Kineflex disc was designed primarily for patients with advanced motion segment degeneration using a simple insertion technique allowing powerful distraction and posterior placement within the disc space.
  • The insertion of the assembled prosthesis enables free articulation of the endplates, allowing the superior and inferior endplates to be advanced independently.
  • Good short term clinical results have been achieved at a minimum follow-up of two years.

Surgical recovery

All patients, with the exception of extensive, combined anterior and posterior lumbar fusions, are mobilised out of bed on the day following surgery (day 1).

Lumbar disc replacement and other anterior spinal surgery have potential dangers (vascular bleeding, damage to the urinary system and erectile function in men) which is almost unheard of in posterior surgery.

It results in a degree of post-operative abdominal swelling, but post-operative pain is less and recovery generally quicker than with posterior surgery. Heat sensations in the lower limbs, thigh pain or discomfort, and vague numbness in the lower limbs can occur but are usually temporary. Post-operative retro-grade ejaculation (dry orgasm) is described but has not been encountered by us to any significant degree.

Disc replacement patients, micro-discectomy patients and anterior cervical fusion patients are all usually discharged on day 2 to 4. Patients after posterior fusion surgery stay usually one to two days longer due to stronger post-operative pain.

Anterior cervical fusion patients are required to wear cervical collars for two months when driving, unless a cervical plate or other metal fixation device is inserted. Disc replacement patients are not required to wear any form of supportive bracing post-operatively.

All patients are post-operatively encouraged and shown hamstring, hip and lower back stretching and mobilisation exercises as well as isometric exercises to the supporting musculature. This should be initially supervised by the physiotherapist or biokineticist and an exercise program should be followed life-long.

All patients will be followed up until symptoms have resolved or stabilised (microdiscectomy, decompression surgery), until fusion is achieved (fusion surgery) and yearly (motion preservation surgery and complex fusion procedures).