Introduction

The change of position of the distal pedicle screws with growing rods in relation to vertebral bodies was described as pedicle screws migration. Pedicle screws are subjected to serial distractive forces pushing them down with every distraction; additionally there is continuous growth of the vertebral bodies during the treatment period. These two factors can affect the change of position of the pedicle screws in relation to the vertebrae during the use of growing rods. To our knowledge, this finding has never been studied, confirmed, or quantified.

Spinal Deformity Service, Royal Orthopaedic Hospital, Birmingham, UK

To describe the technique of nonfusion annulotomy and nuclectomy with posterior growing rod instrumentation for the treatment of non-congenital early onset scoliosis

To present our results of the application of this technique in a consecutive series of nine patients with mean follow up of 76 months (range 16 to 123 months)

We undertook retrospective observational casenote and radiograph study of patients with noncongenital early onset scoliosis having annulotomy and nuclectomy at the apex of their respective curves with standard posterior growing rod instrumentation between 1998 and 2009.

10 patients were identified with one excluded due to short follow up period. Of the nine patients included mean follow up was 76 months. Mean age at primary surgery was 71.7 months (range 29- 97 months)

We measured pre and post operative Cobb angle, T1-S1 height change and change in height over the apical segments.

Mean pre op cobb angle was 74° (range 62- 81°). Mean post op cobb angle was 38°. Three patients have completed their treatment programme with a mean number of 9 lengthenings achieved. Six patients are still undergoing lengthenings. CT demonstrates that the annulotmized segment does not fuse at a mean 3.5 years postoperatively. All patients demonstrated growth over total spinal height and also over apical segments which had undergone annultomy/ nuclectomy. We also report complications.

We have demonstrated that anterior annulotomy and nuclectomy with posterior growing rod construct does allow for spinal growth over released segments without autofusion.

Purpose. Management of early onset scoliosis (EOS) can be very challenging. Surgery is indicated when orthotics and casting fail. Growing rod instrumentation has become an effective approach in controlling the deformity while allowing spinal growth. However, as with any surgery, there are known complications including failure of the proximal foundation. We analyzed our patients who underwent growing rod instrumentation and identified factors that were correlated with proximal foundation failure. Method. Our Pediatric Orthopaedic Spine Database (1992–2010) was reviewed for all patients who underwent growing rod instrumentation. Sixty-six patients with EOS were identified and divided into two groups: Group 1 – proximal foundation failure; and Group 2 – no incidents of proximal failure. The two groups were evaluated for differences in age, sex, weight, upper vertebral level in construct, presence of apical fusion, and pre-operative curve magnitude. Results. Eight of the 66 patients (12%) had proximal foundation failure. When comparing Group 1 and Group 2, only age, pre-operative kyphosis, and presence of apical fusion were significant differences between the two groups. The mean age of Group 1 patients was 4.9 years (range, 2.6 to 9.2 years) and the mean age of Group 2 patients was 7.5 years (range, 2.4 to 11.6 years) (p <0.006). The mean pre-operative kyphosis in Group 1 was 71 degrees compared to 50 degrees in Group 2 (p=0.049). Among the 12 patients with apical fusion, four (33%) had proximal failure. The presence of apical fusion was also a significant difference between the groups (p=0.003). Linear regression demonstrated a significant correlation between kyphosis and failure (k=0.005, p-value 0.016) as well as age and pullout (k=−0.005, p-value <0.01). Conclusion. Our data indicates that younger patients with increased pre-operative kyphosis are at a higher risk for proximal failure of their growing rods resulting in increased incidence of unplanned surgeries. The presence of an apical fusion was also correlated to increased failure rates possibly due to stress at the proximal construct. Further research is needed to determine if stronger constructs decrease the pullout rate in the at-risk patients

The June 2012 Children’s orthopaedics Roundup³⁶⁰ looks at; open reduction for DDH; growing rod instrumentation for scoliosis; acute patellar dislocation; management of the relapsed clubfoot; clubfoot in Iran; laughing gas and fracture manipulation; vascularised periosteal fibular grafting for nonunion; slipped upper femoral epiphysis; intramedullary leg lengthening and orthopaedic imaging and defensive medicine.