Surgical treatment of neurological scoliosis using hybrid construct (lumbar transpedicular screws plus thoracic sublaminar acrylic loops)

Abstract

In the nineties, most spinal surgeons supported the validity of segmental spine instrumentation, but this procedure has progressively been abandoned because difficult and with a high risk of neurological complications, in favor of the Cotrel-Dobousset (CD). The CD instrumentation is based on segmentation of curves, thus improving the angular correction and actuates sagittal profile. Sublaminar acrylic loops (Universal Clamp) shows the same resistance to stress as steel or titanium alloy sublaminar wires. The simple procedure and the tensioning of the strips allows re-tensioning and progressive correction. The increased contact area, improves corrective forces, thus reducing the risk of laminar fractures. The aim of this study was to verify the validity of this spinal fixation implant in the surgical treatment of a consecutive series of patients affected by neurologic scoliosis. The authors treated surgically 84 patients affected by neurologic scoliosis with an average age of 14 years (range 10-17). Universal Clamps associated with Socore TM spinal assembly, transpedicular lumbar screws and thoracic hooks at the upper end of the curve were used. The etiology of disease was cerebral palsy in 81 cases, Friedreich ataxia in two cases and Aicardi syndrome in one case. The average preoperative angular value was 73°± 16°. It was implanted a mean of seven Clamps for each procedure (range 5-9). The average percentage of correction was 72%. Mean operative time was 240 ± 30 min with mean blood loss of 1200 ± 400 ml. No intra-operative complications occurred. Mean follow-up was 36 months. At one-year follow-up the mean loss of correction was 7°± 2°with no re-intervention required. This is the first report on treatment of neurological scoliosis with this hybrid construct (lumbar screws, thoracic acrylic clamps, thoracic hooks at the upper end of the curve). In this group of patients the Universal Clamps technique appeared safe and effective and its mechanical performance is comparable to all-level screws construct. Furthermore, the kyphotic component can be better managed in case of thoracic lordosis. The most important aspect of this technique is a short operative time and low vascular and neurologic risks combined with a satisfying stability in the short-postoperative period. Nevertheless, it is important to value results on a long-term follow-up to analyze correction loss, pseudoarthrosis, and mechanical failure of the strips.

Use of the Universal Clamp in adolescent idiopathic scoliosis for deformity correction and as an adjunct to fusion: 2-year follow-up

“…The promising intermediate-term safety results of sublaminar UCs are in contrast to the intermediate-term safety issues of sublaminar wiring [17][18][19]. La Rosa et al also noted the safety of UCs used in hybrid constructs with thoracic hooks and lumbar pedicle screws in a series of 15 patients with neurological scoliosis greater than 100°and an average followup of 3 years [20]. An apparent superiority in both intraoperative and intermediate-term safety of UCs compared to sublaminar wires has also been discussed by spinal surgeons who reported the use of UCs in the thoracic spine for traumatic vertebral lesions [21].…”

“…This confirmed an earlier study by Ilharreborde et al, who reported an average initial thoracic main curve correction from 60°pre-operatively to 20°(66% correction) in 75 AIS patients treated with UC hybrid constructs and a subsequent loss of only 2°(3%) at the 2-year follow-up [13]. In the series of 15 patients with more severe, neurological scoliosis[100°, La Rosa et al achieved a 70% initial reduction (from 107 to 32°) and lost only 7°of correction after an average follow-up of 3 years [20]. The intermediate-term results reported here on the corrective efficacy of the UC in the coronal plane are not inferior to results observed with other spinal anchors that have known safety issues [2,[22][23][24][25][26][27]].…”

Sagittal profile control in patients affected by neurological scoliosis using Universal Clamps: a 4-year follow-up study

“…Mean radiation exposure time was 6 ± 1.5 s. We used a mean of six transpedicular screws (range 4-11), seven UC (range 5-9) and five hooks (range 4-6). Results and complications have been described in detail in the previous report [10]. Concerning post-operative thoracic kyphosis, the authors noted that it is not possible to define a clear percentage of correction, in absence of an actual range of ''normal value''.…”

“…The Universal Clamp is characterized by three components: a woven polyester band (Dacron), a titanium alloy (or stainless steel) clamp and a locking screw (titanium alloy or stainless steel). The surgical technique has already been described in previous study [10].…”

“…Many thoracic anchors could be used to replace the thoracic pedicle screws in hybrid constructs, including hooks, sublaminar wiring, intraspinous wiring and soft sublaminar bands [4][5][6][7][8][9]. We previously published a case-series study on surgical treatment of neurological scoliosis using a hybrid construct consisting of lumbar transpedicular screws plus thoracic sublaminar acrylic loops (Universal Clamp-UC), reporting a good correction of the deformity in the coronal plane (72 ± 7%) with a reduction in operative time, radiation exposure time and blood loss compared to all-screw constructs [10]. The UC technique has first been described by Mazda et al [11].…”