Standard Titanium Elastic Nail (TEN; Synthes, Welwyn Garden City, UK) fixation requires a 2.5mm drilled entry point at the base of the metacarpal. This can damage soft tissues including the extensor tendon and also risks breaching the volar cortex. We recommend opening the dorsal metacarpal cortex with a curved artery clip (Fig 1). Initially, point the tip downwards to penetrate the cortex, turning the clip 180° to advance it down the medullary canal (Fig 2). The curve on the clip mimics the profile of a 2.0mm TEN (Fig 3) and its natural entry to the metacarpal. The less traumatic nature of this approach may lead to improved soft tissue protection. Figure 1 Entry point gained using clip to penetrate the near cortex Figure 2 Clip turned 180° to continue along medullary canal Figure 3 Titanium Elastic Nails, showing the curved profile

Extensor tendon ruptures have been reported in up to 8.8% of patients after volar plating and long screws have been implicated. The dihedral dorsal surface of the distal radius hinders accurate screw length determination using standard radiographic views (lateral; pronation and supination). A ‘dorsal tangential’ view has recently been described, but has not been validated. To validate this view, we mounted a plate-instrumented sawbone onto a jig. Radiographs at different angles were reviewed independently by 11 individuals. Skyline views clearly demonstrated all screw tips, whereas only 69% of screw tips were identifiable on standard views. With screws 2mm proud of the dorsal surface, skyline views detected 67% of long screws (sensitivity). The best of the standard views achieved only 11% sensitivity. At 4mm long, skyline sensitivity was 85%, compared with 25% for standard views. At 6mm long, 100% of long screws were detected on skylines, but only 50% of 8mm long screws were detected by standard views. Inter and intra-observer variability was 0.97 (p=0.005). For dorsal screw length determination of the distal radius, the skyline view is superior to standard views. It is simple to perform and its introduction should reduce the incidence of volar plate-related extensor tendon rupture.

We read with interest your paper and commend the authors for producing a well-designed study that addresses an important clinical problem.1 We feel there are three simple techniques that can minimise the risk to these dorsal structures. A proportion of tendon ruptures are due to iatrogenic injury during drilling of the screw holes.2,3 We recommend using an appropriately sized Kirschner wire to drill the ‘at risk’ holes as this is less traumatic when compared to the cutting flutes of a drill. We agree that long screws may cause attrition of the tendons over time.1,2 We advocate the use of smooth locking pegs or tines rather than sharptipped self-tapping screws. Rather than leaving the ‘at risk’ holes empty, we employ unicortical purchase. The ‘at risk’ holes of the three plates you analysed direct screws into an area that often has the best bone stock, providing the basis for sound fracture stabilisation and correction of radial height and inclination. The use of these techniques, combined with the knowledge of ‘at risk’ screw holes, should considerably reduce the risk of extensor tendon ruptures in these cases. Thank you for an interesting paper and one that has such relevance to common orthopaedic trauma practice.

TECHNIQUE a sterilised drain set is used; small side holes are made in the tubes using scissors (average 6–10 holes) (Fig 1). The drip bag is emptied and a negative pressure is created (Fig 2). (Saline is used for the operation and is not discarded.) The drip set is connected to the bag to act as a suction drain. The roller clamp can be used to control flow and prevent the loss of negative pressure when changing the bottle. it can also be used as a simple drain. The closed drainage system helps to prevent infection. DISCUSSION We have used this technique in over 50 patients in Gadarif Teaching hospital. it is effective, cheap, removal is simple and we did not encounter any problems.

Introduction: Cervical spine pedicle morphology has been assessed by direct measurement and by CT in cadavers. We have assessed reproducibility and produced data for normal ranges in live subjects from the UK. Method: 54 axial CT scans were examined. All subjects were scanned for the exclusion of fracture between December 2003 and December 2004. The digitised images were analysed on the Philips PACS system using SECTRA software. 168 individual vertebrae were assessed between C3 and C7. The following were measured; the angle of the pedicle relative to the sagittal plane, the smallest internal and external diameter, the angle of the lamina and the distance from the lateral mass to the anterior vertebral body (LMAVB) in the line of the pedicle. Reproducibility was assessed in a subset of 10 individuals with paired measures using the FDA approved formula for CV%. Results: Angular measures had a CV% of 3.9%. The re-measurement error for distance was 0.5mm. 338 pedicles were assessed in 25 females and 29 males. Average age was 48.2 years (range 17–85). Our data from live subjects was comparable to previous cadaveric data. Mean pedicle external diameter was 4.9mm at C3 and 6.6mm at C7. Females were marginally smaller than males. Left and right did not significantly differ. Mean LMAVB was 34mm (min 21mm). In no case was the pedicle narrower than 3.2mm. Mean pedicle angle was 130 deg at C3 and 140 deg at C7. Conclusions: CT measurement has acceptable reproducibility. Previous cadaveric measurements have been validated in live subjects in the UK. Although there is some variation in morphology, instrumentation no wider than 3.0mm and no longer than 20mm is unlikely to prove too large for an adult pedicle.

We have assessed the clinical observation that the angle of the contralateral lamina matches the angle required from the sagital plane for the placement of pedicle screws in the subaxial cervical spine. Fifty-four randomly chosen axial CT scans taken between December 2003 and December 2004 were examined. Subjects were excluded if the scan showed signs of fracture, tumour or gross abnormality. The digitised images were analysed on the Philips PACS system using SECTRA software. One hundred and sixty-eight individual vertebrae were assessed between C3 and C7. The following were measured; the angle of the pedicle relative to the sagital plane, the smallest internal and external diameter of the pedicles and the angle of the lamina. Angular measures had a CV% of 3.9%. The re-measurement error for distance was 0.5 mm. Three hundred and thirty-six pedicles were assessed in 25 females and 29 males. Average age was 48.2 years (range 17–85). Our morphologic data from live subjects was comparable to previous cadaveric data. Mean pedicle external diameter was 4.9 mm at C3 and 6.6 mm at C7. Females were marginally smaller than males. Left and right did not significantly differ. In no case was the pedicle narrower than 3.2 mm. Mean pedicle angle was 130° at C3 and 140° at C7. The contralateral laminar angle correlated well at C3, 4, 5 ( R 2 = 0.9, C3 P = 0.002, C4 P = 0.06, C5 P = 0.0004) and was within 1° of pedicle angle. At C6, 7 it was within 11°. In all cases a line parallel to the lamina provided a safe corridor of 3 mm for a pedicle implant. The contralateral lamina provides a reliable intraoperative guide to the angle from the sagital plane for subaxial cervical pedicle instrumentation in adults.