Introduction

Halo traction, either on bed or with an accompanying vest is used commonly in Spine surgery, in a variety of clinical situations. The pins are inserted into the skull in safe anatomic zones, using wrenches that are either pre-torqued or exhibit a torque gauge to allow measurable torque application. A torque of 6 – 8 inch pounds is considered ideal for optimal pin tightening. Lesser torques may hypothetically lead to pin loosening and pin track infections, while, excessive torques could lead to pin penetration through the skull.

We do know that the use of stand-alone cage with no plate is prone to subsidence and segmental kyphosis. Cage and plate construct are prone to adjacent level ossification. Zero P (Synthes, UK) cage combines the functionality of spacer and anterior plate.

Radiological evaluation of subsidence of cervical spine after anterior cervical interbody fusion using Zero P cage system.

Method: Retrospective review of radiographic records of patients undergoing surgery between June 2008- Oct 2009. We evaluated lateral cervical standing radiographs before, after, 6 weeks, 3, 6 months of surgery. We measured subsidence (using Total Intervertebral Height (TIH). All measurements were done using Web 1000 (Impax Agfa). Two level was treated as single segment. Subsidence > 3mm was considered significant.

20 patients (11 male: 9 female) with median age of 51 yrs (40-65) underwent one (n=10) or two level (n= 10) cervical fusion. Immediately post-op there was increase in TIH in one and two level group by 1.74mm (1.61 and 4.25mm (1.48 respectively, which at 6 months reduced to 1.05mm (0.24 (p< 0.003) and 1.32mm (1.29 (p< 0.085) at 6 months respectively. Subsidence was seen in all cases and was rapid in first 3 months and then tailed off. It was significant (> 3mm) only in 2/20 (2%) patients at 6 months.

Early results indicate that spine alignment is maintained radiologically with no associated complications as screw loosening, cage extrusion etc.

To evaluate Radiological changes in the lumbosacral spine after insertion of Wallis Ligament for Foraminal Stenosis.

Thirty two Levels in Twenty Six patients were followed up with standardised radiographs after insertion of Wallis Ligaments for Foraminal Stenosis. Wallis ligaments as a top-off or those with prolapsed discs were not included. The Radiological parameters compared were Anterior and Posterior Disc height, Foraminal height and width, The inter-vertebral angle (IVA), Lumbar lordosis and Scoliosis if any. The presence of slips and their progression post-op was noted, as was bony lysis if any.

There were ten males with thirteen levels and sixteen females with nineteen levels in the study. Eighteen levels (56.25%) were L4/L5, ten (31.25%) were L5/S1 and 4 (12.5%)were L3/L4. The average age in the series was 59.6 years (Range 37 – 89 yrs). Average follow up was 9.5 months (Range 2 to 36). The Average increase in Anterior disc height was 1.89 mm (+/−1.39), the posterior disc height increased by an average 1.09 mm (+/−1.14). Foraminal height increased by an average 3.85 mm (+/− 2.72), while foraminal width increased by 2.14 mm (+/− 1.38). The IVA increased in 16 and reduced in 15 patients, with no change in 1. Lumbar Lordosis increased in 23 patients, with an average value of 2.3°. No patient exhibited progression in scoliosis and no lysis could be identified. There were three Grade I slips pre-op; none progressed.

Foraminal dimensions and Disc height were consistently improved after Wallis insertion. Changes in IVA and Lumbar lordosis were however variable. A longer follow up is suggested to look for sustained improvement and the presence of lysis.