The current trend in kyphosis correction is for “every level” instrumentation to achieve intraoperative stability, correction, fusion and implant longevity.

We evaluate the medium term follow up of a low implant density (LID) construct.

All patients with adolescent kyphosis (idiopathic or Scheurmann's) on our deformity database were identified. Radiographs and records were analysed for neurological complications, correction and revision.

The constructs included were all pedicle screw anchors with multiple apical chevron osteotomies and a proximal and distal “box” of 6 to 8 screws. A four rod cantilever reduction manoeuvre with side to side connectors completed the construct. Kyphosis for any other cause was excluded. Follow up less than 12 months was excluded.

23 patients were identified with an average follow up 27 months (72 to 12 months) and a mean implant density of 1.1 (53.5% of “available” pedicles instrumented).

There was 1 false positive neurophysiological event without sequelae (4%).

There were no proximal junctional failures (0%).

There were no pseudarthroses or rod breakages (0%).

There was 1 loss of distal rod capture (early set screw failure) (4%). This was revised uneventfully.

There were 4 infections requiring debridement (early series).

Average initial correction was 44% (77.7 degrees to 43.5 degrees) with a 1% loss of correction at final follow up (43.5 to 44.0 degrees). The fulcrum bending correction index was 107% (based on fulcrum extension radiographs). 85% of curves had a fulcrum flexibility of less than 50%.

The average cost saving compared to “every level “instrumentation was £5700 per case.

This paper shows that a LID construct for kyphosis has technical outcomes as good as high density constructs. The obvious limitation of the study is the small number of patients in the cohort.

The infection rates have improved with changes to perioperative process in the later series of patients. We do not believe these are a consequence of the construct itself.

The purpose of this study is to investigate what effect cross links have on scoliosis constructs and whether cross links may be used instead of pedicle screws at the apex of the deformity

The rotational stiffness of six different construct designs was investigated on scoliotic sawbone models with zero, one or two cross links. In three of the constructs the screws at the apex were removed. Testing was performed to an average torque of 3Nm and ration was detected using electromagnetic motion tracking system.

The stiffness in axial rotation of all constructs increased with the number of cross links, however the difference was not statistically significant. In constructs with apical screws the stiffness increased by 3.01% and 12.9% for one and two cross links respectively. In constructs without apical screws the increase was 1.64% and 14.3% for one and two cross links respectively.

The total stiffness of the construct increased with the addition of apical screws by 20%, 21.7% and 18.8% for zero, one and two cross links respectively. This increase was statistically significant using a paired t-test (p= 0.01142).

On the basis of these results we conclude that the use of cross links in scoliosis correction surgery is not necessary. Pedicle screws positioned at the apex of the scoliosis curve statistically increase the stiffness in axial rotation and are therefore necessary to promote an environment suitable for bony fusion.

Introduction:

Shoulder balance after surgery is one main attribute of the cosmetic outcome. It has been difficult to assess on 2D images. The balance results from the interaction of rib cage, shoulder joint and scapular positions, spinal alignment and rotation, muscle size and co-ordination and pain interaction. Attempts have been made to predict shoulder balance from radiograph measurements. There is no consensus on this.

Aim:

To evaluate the effect of intraoperative manoeuvres on the rib hump.

Aim:

To evaluate the effect of a stiffer rod in normalising thoracic hypokyphosis in adolescent idiopathic scoliosis (AIS).

Introduction:

Scheuermann's kyphosis is a fixed round back deformity characterised by wedged vertebrae seen on radiograph. It is known patients presented with a negative sagittal balance before operation. Few studies investigated the outcome after operation, especially the change in the lumbar hyperlordosis.

Pedicle screw constructs (PSC) in scoliosis are a recently established and widely accepted method of managing scoliotic curves posteriorly. There is a perceived improved coronal and rotational correction when compared to other posterior only constructs. With continued use of this method, the authors and deformity surgeons in general have become aware of persistent thoracic hypokyphosis.

This review of 3 years of scoliosis cases using PSC looks at four different implant strategies utilised to manage this problem and our current practice. These strategies were:

All titanium 5.5 mm rod diameter (Expedium, Depuy spine)

All titanium 5.5 mm rod diameter with periapical washers (Expedium, Depuy spine)

All titanium 6.0 mm rod diameter (Pangea, Synthes)

Titanium pedicle screws with 5.5 mm diameter cobalt chrome rods (Expedium Depuy spine)

We have reviewed our outcomes with these strategies with respect to thoracic hypokyphosis. Strategy 1 had the highest rate of hypokyphosis on postoperative radiographs. Strategy 4 seems to have the best correction of coronal and sagittal plane abnormality post operatively. As a consequence, our current practice is the use of titanium pedicle screws and 5.5 mm diameter cobalt chrome rods when managing scoliosis with a pedicle screw construct.