Cost comparison of femoral head banking versus bone substitutes.

PURPOSE: To compare the costs of femoral head banking versus bone substitutes. METHODS: Records of femoral head banking from 1998 to 2008 were reviewed. The cost of allogenic cancellous bone graft was calculated by estimating the direct expenditure of femoral head procurement, screening tests, and storage, and then divided by the amount of bone harvested. RESULTS: 326 females and 141 males (mean age, 80.3 years) donated 470 femoral heads. Each transplantable femoral head costs US$978. Each gram of transplantable allogenic bone graft costs US$86, compared with US$9 to 26 per gram for commercially available bone substitutes. CONCLUSION: Compared with bone substitutes, femoral head banking in Hong Kong was less economical. Unless allografts yield superior outcomes, harvesting femoral heads for general usage (such as filling bone voids for fresh fractures) is not justified from a financial perspective, especially in banks dedicated to procuring bone from femoral heads only.

Pick-up test: an indication for opponensplasty in patients with severe carpal tunnel syndrome.

PURPOSE: To use a pick-up test to assess thenar motor deficit and results of opponensplasty. METHODS: Eight consecutive patients with idiopathic severe carpal tunnel syndrome and severe thenar motor deficit were identified. All were females aged 39 to 60 (mean, 53) years and right-hand dominant. The severity of thenar motor deficit was assessed using the pick-up test. Failure to pick up a coin with the thumb and index finger only in a normal pulp-to-pulp pincer grip was an indication for an opponensplasty (in addition to open carpal tunnel release) to hasten recovery of thumb abduction. Treatment outcome was assessed using the pick-up test at 6, 8, and 12 weeks. RESULTS: Preoperatively, all patients were unable to perform the pick-up test. At postoperative 6 weeks, all patients could pick up the coin with no difficulty and were satisfied with the result of opponensplasty. There was no relapse at subsequent follow-ups and no donor-site morbidity in terms of cosmesis, scar pain or infection. Grip strength and the range of wrist motion were 63% and 92% of the normal side, respectively. CONCLUSION: The pick-up test is a simple and reliable means of identifying those in need of an opponensplasty.

Effects of hip joint position and intra-capsular volume on hip joint intra-capsular pressure: a human cadaveric model.

BACKGROUND: Increase in hip intra-capsular pressure has been implicated in various hip pathologies, such as avascular necrosis complicating undisplaced femoral neck fracture. Our study aimed at documenting the relationship between intra-capsular volume and pressure in various hip positions. METHODS: Fifty-two cadaveric hips were studied. An electronic pressure-monitoring catheter recorded the intra-capsular hip pressure after each instillation of 2 ml of normal saline and in six hip positions. RESULTS: In neutral hip position, the control position for investigation, intra-capsular pressure remained unchanged when its content was below 10 ml. Thereafter, it increased exponentially. When the intra-capsular volume was 12 ml, full abduction produced a 2.1-fold increase (p = 0.028) of the intra-capsular hip joint pressure; full external rotation and full internal rotation increased the pressure by at least 4-fold (p < 0.001). Conversely, there was a 19% (p = 0.046) and 81% (p = 0.021) decrease in intra-capsular hip joint pressure with flexion of the hip joint to 90-degree and 45-degree, respectively. CONCLUSION: Intra-capsular pressure increases with its volume, but with a wide variation with different positions. It would be appropriate to recommend that hips with haemarthrosis or effusion should be positioned in 45-degree flexion.

Laminoplasty after anterior spinal fusion for cervical spondylotic myelopathy.

PURPOSE: To review outcomes of laminoplasty after anterior spinal fusion (ASF) in 8 patients with cervical spondylotic myelopathy (CSM). METHODS: Records of 3 men and 5 women aged 49 to 80 (mean, 60) years who underwent laminoplasty after ASF for CSM were reviewed. Before and after ASF and laminoplasty, the causes of CSM, mechanical instability, the Pavlov Torg ratio, the numbers of levels of stenosis, myelomalacia, ASF, and laminoplasty, the modified Japanese Orthopaedic Association (JOA) score, and the Hirabayashi recovery rate were recorded in all the patients. RESULTS: After ASF, the mean modified JOA score improved to 9.6 from 8.3 (p=0.05), with a mean Hirabayashi recovery rate of 12.5% at the 12-month follow-up. However, it deteriorated to 9 after a mean of 25 (range, 3-54) months follow-up. Indications for a secondary laminoplasty included inadequate decompression (n=5), progression of prolapsed discs (n=4), osteophytes (n=3), ossification of the posterior longitudinal ligament (n=1), and hypertrophy of the ligamentum flavum (n=4). The mean interval between ASF and laminoplasty was 30 (range, 14-55) months. The mean number of levels of laminoplasty was 4.5 (range, 4-5). After laminoplasty, all patients had adequate spinal decompression with no cord compromise, neck pain or stiffness, despite the signal change remaining the same. Two patients improved, 2 deteriorated, and 4 remained unchanged with respect to walking status. The mean modified JOA scores improved to 9.7 from 9 (p=0.38); the mean Hirabayashi recovery rate was -1.5%. All patients had persistent myelomalacia, which was not reflected in the improved modified JOA score. CONCLUSIONS: Initial surgery (such as ASF) is more effective in relieving cord compromise and myelopathy. Inadequate decompression and progression of disease may necessitate secondary laminoplasty, which conferred additional benefits that 5 of our 8 patients enjoyed despite persistence of myelomalacia.

Consequence of paraspinal muscle after spinal fusion: an experimental study.

Posterior lumbar spinal fusion is a common surgery of spine. The parapsinal muscular dysfunction was postulated to be due to injured paraspinal muscle inflicted by the surgery. To better understand the muscle dysfunction after spinal fusion, this descriptive study evaluated electrophysiology and histology changes in paraspinal muscle of rabbits with and without fusion. Three New Zealand white rabbits underwent 2-level posterior spinal fusion with instrumentation. Anothor 3 rabbits underwent surgical exposure alone and served as sham control. Pre-operative and follow-up electromyography (EMG) and histological assessment were performed in a 6-month interval. All fusion achieved solid union judged by post-mortem examination. Root mean square (RMS) of EMG showed decrease in both fusion and control group immediately after surgery, but the control group recovered to pre-operative value at 6 months follow-up. At 6 months after operation, the fusion group showed lower RMS in fused region than adjacent region. In term of median frequency (MF) changes, the control group did not show obvious difference between pre- and post-operative period. However, fusion group showed obvious decrease of MF in fusion region, but increase in lower adjacent region. Histology reviewed fatty infiltration in fusion region at 6 months after spinal fusion. In addition, the muscle fiber size presented smaller in fusion region than that of pre-operative status. These results would demonstrate the lower activities and muscle disuse atrophy of paraspinal muscles in the fusion region. While, higher muscular activities were found in the lower adjacent region, which may indicate muscle hypertrophy.