Sagittal balance parameters influence indications for lumbar disc arthroplasty or ALIF

Abstract

Chronic lower back pain is a potentially incapacitating condition associated with disc degeneration. Although therapy is primarily pharmaceutical, surgery comprising arthrodesis constitutes an alternative. Anterior intersomatic lumbar arthrodesis (ALIF, anterior interbody lumbar fusion) is the reference approach, although total disc arthroplasty may also be undertaken. Analysis of pelvic and spinal parameters provides the best indication of sagittal balance. Materials and methods This was a prospective study in a continuous series of 99 patients presenting chronic lower back pain due to disc disease. Pelvic incidence, sacral slope, pelvic tilt, spino-sacral angle (SSA) and the four back types in the Roussouly classification were studied in radiographs of the whole spine under load using an EOS imaging system. Results The pre-operative SSA value for the study population was 126.09°± 8.45°and the mean spine tilt angle was 90°compared with 95°in healthy subjects. Following surgery, the SSA was considerably increased in the discal arthroplasty, resulting in a significantly more balanced spinal position. In the group of patients undergoing arthrodesis using the ALIF technique, no such significant improvement was found despite the use of a lordosis cage. We showed that in cases of low pelvic incidence, it was necessary to maintain a Roussouly type 1 or 2 back without increasing lordosis. The results demonstrated the value of L4-L5 disc prostheses in these subjects. L5-S1 arthrodesis seemed a more suitable approach for treating patients with elevated sacral slope (back type 3 or 4). This new type of analysis of sagittal parameters should be performed prior to all surgical procedures involving lumbar prostheses.

Influence of transforaminal lumbar interbody fusion procedures on spinal and pelvic parameters of sagittal balance

“…The preoperative analysis of spinal and pelvic sagittal balance is essential, because it helps in determining how much correction is needed, and then in choosing the type of procedure required to reach this goal [18,19]. In addition, restoring spinal sagittal balance has been reported to improve fusion rates and reduce the rate of adjacent segment disease [20][21][22].…”

Two-piece ALIF cage optimizes the bone–implant interface in a 360° setting

“…Clinical fusion studies indicate that standard lordotic interbody cages seldom improve the patient's sagittal balance, but generally, they improve the disc height and fusion rate [5][6][7]. Disc arthroplasty was introduced as an alternative to fusion and to prevent possible known complications following lumbar fusion.…”

“…An hypothesis for these findings could be that the degenerated spine benefits from allowing alignment adjustment, meaning better alignment between implant footprint and vertebral endplates; combined with the fact that lumbar degenerated spines quite often auto-fuse [7,15].…”

Reproducibility and Equivalence of Cobbmeter Application in the Sagittal Evaluation of the Spine

“…[1][2][3][4][5][6][7][8] The correct alignment of the bony structures and their articulations is fundamental to the proper functioning of the musculoskeletal system. 9 Furthermore, their complex interactions with the nervous system and subsequent muscle recruitment are essential to ergonomic balance and the maintenance of upright posture with minimal energetic expenditure, thus allowing the deliberate movement of the human body.…”