Faculty Bibliography

Although occipitocervical fusion is frequently used for instability of the upper cervical spine and the occipitocervical articulation, most currently used techniques have one or more of the following disadvantages: the necessity for sublaminar wires, the use of occipital screws, a fixed angle of instrumentation, or the necessity for routine postoperative halo immobilization. Moreover, many reported techniques are associated with a high rate of nonunion or instrumentation failure. We present our experience with a technically simple method of obtaining rigid occipitocervical arthrodesis using a 5-mm malleable rod that is fixed to the skull by a pair of wires passed through four suboccipital burr holes. Segmental spinal fixation is achieved with Wisconsin interspinous wires and is occasionally supplemented with sublaminar wires. Supplemental autogenous bone graft is used in all cases. A cervical collar is routinely used for postoperative immobilization. The results of treatment were retrospectively reviewed in 16 patients with an average age of 49.4 years (range, 9-69). Mean follow-up was 24 months (range, 12-36 mo). The indication for fusion was instability of the occiput-C1-C2 complex as a result of Chiari malformation, rheumatoid disease, skull base tumor resection, basilar invagination, ankylosing spondylitis, Down's syndrome, cervical laminectomy, and trauma. The average number of levels fused was 5.4 (range, O-C3 to O-T3). Successful occipitocervical arthrodesis was achieved in all but one of the surviving patients. The single patient with a pseudarthrosis was successfully managed with supplemental bone grafting and halo immobilization. There were two deaths from medical complications in chronically ill patients. Other complications included one postoperative instrumentation loosening, one myocardial infarction, and one superficial occipital decubitus. In conclusion, rodding and segmental interspinous wiring is an effective, technically simple method of obtaining rigid occipitocervical fixation, which obviates the need for bulky orthoses

We undertook a biomechanical study to compare the pullout strength of 3.5-mm AO screws placed in two different orientations within the bovine cervical spine. The first set of screws were oriented obliquely and passed through the lateral mass, as recommended by the AO group. The orientation of the second set was anterior to posterior through the lateral mass, as recommended by Roy-Camille. All screw holes were drilled and tapped by a spinal surgeon experienced with both techniques. Pullout force was measured on an Instron materials testing machine using a self-centering screw-holding chuck and loading rate of 0.833 mm/sec. Although the bone strength in the Roy-Camille orientation was greater (46.7 N/mm versus 36.1 N/mm, p < 0.05), the overall mean pullout force for the AO orientation was greater (607 N versus 471 N, p < 0.025) due to the longer length of bone available for screw purchase (17.0 mm versus 10.3 mm)

Prior irradiation and scarring can complicate wound closure following spinal surgery. Implanted tissue expanders were used six times in four patients to aid skin closure. Three patients had prior irradiation for cancer, and one had myelomeningocele. The average interval between placement and removal of the expanders was 46 days. Two late failures occurred because of prominent hardware. These expanders may provide adequate myocutaneous covers following spinal surgery in difficult cases

Cervical spine injuries pose devastating potential problems for surgeon and patient alike. This review will stress the early diagnosis of cervical spine injuries, with emphasis on early suspicion of injury. This review will focus on the radiology and types of lesions found with cervical spine injury

The indications and techniques for internal fixation of the lumbar spine in degenerative conditions have changed drastically since internal fixation was first applied to the spine almost 100 years ago. Anterior instrumentation and fusion may be used for repair of pseudarthrosis after posterolateral fusion; symptomatic lumbar scoliosis associated with degenerative disc disease; late pain secondary to posttraumatic kyphosis; postlaminectomy instability; and lumbar pain secondary to thoracolumbar kyphosis. Posterior instrumentation and fusion has been performed with Luque instrumentation over 3-4 levels in cases of multilevel instability. Combined anterior and posterior instrumentation and fusion are required for lumbosacral fusion in lumbar scoliosis with degenerative disease, and surgical correction of postsurgical lumbar kyphosis (flat-back syndrome). The techniques are demanding but with attention to detail can be performed with acceptably low-complication rates

Heterotopic ossification can impair the functional results of total hip arthroplasty. The causative role of trochanteric osteotomy in heterotopic ossification is uncertain. Postoperative radiographs of 100 total hip arthroplasties were analyzed for incidence of heterotopic ossification. Forty procedures were performed with trochanteric osteotomy and 60 without. There was a 17% overall incidence of clinically significant heterotopic ossification, 22% with osteotomy and 13% without. High- and low-risk categories revealed clinically significant heterotopic ossification in 25% of the high-risk group and in 8% of the low-risk group. In the high-risk group there was a 32% incidence with trochanteric osteotomy and 22% without osteotomy. In the low-risk group there was a 16% incidence without trochanteric osteotomy and a 3% incidence with trochanteric osteotomy. The increase in clinically significant heterotopic ossification in the high-risk group over that of the low-risk group was statistically significant. The present study showed that trochanteric osteotomy tended to increase the incidence and severity of clinically significant heterotopic ossification. These data suggest that trochanteric osteotomy should be avoided, if possible, during total hip arthroplasty to decrease the risk of heterotopic ossification