Postoperative wound infection after instrumentation of thoracic and lumbar fractures.

OBJECTIVE: To assess the risk of infection in trauma patients undergoing surgical intervention with instrumentation for thoracic and lumbar fractures. DATA SOURCES: A case series of 235 consecutive patients who sustained thoracic and lumbar fractures seen at Tampa General Hospital in Tampa, Florida between 1986 and 1997. STUDY SELECTION: 117 patients of the 235 consecutive patients included in the case series underwent surgical intervention; of these patients, twelve were identified as having acute postoperative wound infections. DATA EXTRACTION: Of those patients treated with operative decompression and internal fixation, the authors identified and studied those with an acute wound infection. These patients were analyzed for risk factors and infection management. DATA SYNTHESIS: Twelve (10 percent) patients with acute postoperative wound infections were identified. These included nine deep and three superficial infections. This provides an overall infection rate of 10 percent (12 of 117). Of these, there were three infections in twenty-one patients undergoing anterior spinal procedures. Only two of the twelve patients had pure cultures of gram-positive organisms (2 Staphylococcus aureus). Cultures from eight (67 percent) patients showed multiple organisms. There was a significantly (P < 0.05) higher risk of infection in the patients with a complete neurologic injury 41 percent (7/17) as compared with those with no deficit or incomplete injuries 5.0 percent (5/100). CONCLUSIONS: The overall risk of infection is higher in the trauma patient than in the elective surgery population. Those patients with a complete neurologic deficit are at a greater risk. Aggressive and early intervention can help contribute to a favorable outcome.

Three- and four-level anterior cervical discectomy and fusion with plate fixation: a prospective study.

STUDY DESIGN: A prospective study of 15 patients who underwent modified Smith-Robinson anterior cervical discectomy and fusion at three or four operative levels stabilized with an unicortical anterior plate. OBJECTIVES: To provide medium-term follow-up data on the surgical success and patient outcome of three- and four-level anterior cervical discectomies and fusions and to determine the effect that plate fixation has on the results. SUMMARY OF BACKGROUND DATA: The success of arthrodesis for anterior cervical fusion depends on several factors, including the number of surgical levels. The arthrodesis rate and outcome for patients having three- and four-level discectomy and fusion procedures is disappointing. Internal fixation putatively improves these parameters. METHODS: Fifteen patients (average age, 51 years; range, 35-77), were observed for an average of 42 months (range, 25-73) All had an anterior discectomy, burring of the endplates, placement of an autogenous tricortical iliac crest graft at three (12 patients) or four (3 patients) levels, and application of a Cervical Spine Locking Plate. All patients had follow-up office visits with examinations and radiographs. Radiographic union, postoperative pain relief, and neurologic recovery were evaluated. RESULTS: Solid arthrodesis was achieved at all levels in only 7 (47%) of the 15 patients after a single procedure. Of the 8 patients with pseudarthrosis, 3 had sufficient pain to necessitate revision surgery (with pain relief in two), 1 had pain without further surgery, and 4 no pain. Of the 7 with solid fusion, 3 had persistent pain, and 4 had none. Two in this group had a second procedure. All 4 patients with preoperative myelopathy improved, and 10 of the 11 with radiculopathy had resolution of arm symptoms. CONCLUSIONS: Three- and four-level modified Robinson cervical discectomy and fusion results in an unacceptably high rate of pseudarthrosis. The Cervical Spine Locking Plate alone does not appear to improve the arthrodesis rate.

Smoking cessation in the spine surgeon's office: a review.

Tobacco abuse is a major health and economic problem in the world today. The spine practitioner has direct experience with the negative effects of the addiction. This review will provide an outline to assist all involved in spine care to help the patient overcome his or her dependence on nicotine. Every practitioner should participate. Even minimal intervention, if carried out at each office visit, can have surprisingly positive effects.

Effect of tryptophan treatment on self-biting and central nervous system serotonin metabolism in rhesus monkeys (Macaca mulatta).

UNLABELLED: Two studies were conducted to examine the effects of oral L-tryptophan (TRP) supplementation as a treatment for self-injurious behavior (SIB) and to investigate behavior and central serotonin turnover of male rhesus monkeys. In Study One, TRP was administered to seven individually housed rhesus monkeys with a recent history of spontaneous SIB. While the monkeys were on TRP treatment (100 mg/kg twice a day), cisternal cerebrospinal fluid (CSF) concentrations of 5-hydroxyindoleacetic acid increased markedly (p = .0013) above baseline (baseline mean = 207.6 pmol/ml +/- 39; TRP mean = 320.3 pmol/ml +/- 83.4), and the duration of self-biting behavior decreased below baseline (p = .03). In Study Two, 14 individually housed rhesus monkeys without a history of SIB were placed on three different doses of TRP in random order (50, 100, and 200 mg/kg twice a day). TRP had no effect on any behavioral or biochemical variables in the normal monkeys. CONCLUSIONS: Supplemental tryptophan in well-tolerated doses reduced self-biting and increases serotonin turnover rate in male monkeys with a recent history of SIB. The same doses of TRP do not affect behavior or serotonin metabolism in male monkeys without a history of SIB.

Anterior cervical decompression and arthrodesis for the treatment of cervical spondylotic myelopathy. Two to seventeen-year follow-up.

We reviewed the cases of 108 patients with cervical spondylotic myelopathy who had been managed with anterior decompression and arthrodesis at our institution. Operative treatment consisted of anterior discectomy, partial corpectomy, or subtotal corpectomy at one level or more, followed by placement of autogenous bone graft from the iliac crest or the fibula. At the latest follow-up examination, thirty-eight of the eighty-two patients who had had a preoperative gait abnormality had a normal gait, thirty-three had an improvement in gait, six had no change, four had improvement and later deterioration, and one had a worse gait abnormality. Of the eighty-seven patients who had had a preoperative motor deficit, fifty-four had complete recovery; twenty-six, partial recovery; six, no change; and one had a worse deficit. The average grade according to the system of Nurick improved from 2.4 preoperatively to 1.2 (range, 0.0 to 5.0) postoperatively. A pseudarthrosis developed in sixteen patients, thirteen of whom had had a multilevel discectomy. Only one of thirty-eight arthrodeses that had been performed with use of a fibular strut graft was followed by a non-union. An unsatisfactory outcome with respect to pain was significantly associated with pseudarthrosis (p < 0.001). The development of complications other than non-union was associated with a history of one previous operative procedure or more (p = 0.005). Recurrent myelopathy was rare, but when it occurred it was associated with a pseudarthrosis or stenosis at a new level. The strongest predictive factor for recovery from myelopathy was the severity of the myelopathy before the operative intervention--that is, better preoperative neurological function was associated with a better neurological outcome. Anterior decompression and arthrodesis with autogenous bone-grafting can be performed safely, and is associated with a high rate of neurological recovery, functional improvement, and pain relief, in patients who have cervical spondylotic myelopathy.

Germ-line mutations in the neurofibromatosis 2 gene: correlations with disease severity and retinal abnormalities.

Neurofibromatosis 2 (NF2) features bilateral vestibular schwannomas, other benign neural tumors, and cataracts. Patients in some families develop many tumors at an early age and have rapid clinical progression, whereas in other families, patients may not have symptoms until much later and vestibular schwannomas may be the only tumors. The NF2 gene has been cloned from chromosome 22q; most identified germ-line mutations result in a truncated protein and severe NF2. To look for additional mutations and clinical correlations, we used SSCP analysis to screen DNA from 32 unrelated patients. We identified 20 different mutations in 21 patients (66%): 10 nonsense mutations, 2 frameshifts, 7 splice-site mutations, and 1 large in-frame deletion. Clinical information on 47 patients from the 21 families included ages at onset and at diagnosis, numbers of meningiomas, spinal and skin tumors, and presence of cataracts and retinal abnormalities. We compared clinical findings in patients with nonsense or frameshift mutations to those with splice-site mutations. When each patient was considered as an independent random event, the two groups differed (P < or = .05) for nearly every variable. Patients with nonsense or frameshift mutations were younger at onset and at diagnosis and had a higher frequency and mean number of tumors, supporting the correlation between nonsense and frameshift mutations and severe NF2. When each family was considered as an independent random event, statistically significant differences between the two groups were observed only for mean ages at onset and at diagnosis. A larger data set is needed to resolve these discrepancies. We observed retinal hamartomas and/or epiretinal membranes in nine patients from five families with four different nonsense mutations. This finding, which may represent a new genotype-phenotype correlation, merits further study.

Vascular injury during lumbar diskectomy associated with peridiskal fibrosis: case report and literature review.

Dense peridiskal fibrosis was encountered during a lumbar diskectomy for a chronic lumbar disk herniation. Posteriorly the adhesions involved the annulus, dura mater, nerve roots, posterior longitudinal ligament, and sequestrated disk material. Anteriorly the iliac vessels were also densely adherent to the disk. When disk material was removed from a standard posterior approach, the left common iliac vein tore, leading to severe hypotension. Vascular injury by instruments has been described by many clinicians, but this indirect mechanism of injury has not been reported in the literature, nor has extensive peridiskal fibrosis been described in a spine without a history of previous surgery.

Axon regeneration after decompression of the conus medullaris.

STUDY DESIGN: The effect of acute spinal stenosis (simulating fracture) and decompression of stenosis on axon regeneration was evaluated in an animal model. OBJECTIVES: Clinical function and quantitative histomorphometry were used to gain insight into the clinicopathologic effects of acute spinal stenosis and decompression. SUMMARY OF BACKGROUND DATA: Decompression of extrinsic compression after thoracolumbar fractures has been suggested to maximize recovery of neurologic function. Clinical studies seem to support this, but the histologic results of decompression are poorly understood. METHODS: Experimental spinal stenosis was created in 5 female beagle dogs, followed by decompression in three of the beagles at 6 weeks. Clinical function and histologic appearance were analyzed using a monoclonal antibody to neurofilaments. RESULTS: Stenosis consistently produced significant neurologic deficit and axon degeneration within motor roots distal to the stenosis. Decompression resulted in improved neurologic function and a tendency for the axons to return to normal number and volume based on quantitative histomorphometry. CONCLUSION: This study provides an animal model and functional and histologic data that support the use of decompression of acute spinal stenosis of 50% or more canal compromise at the level of the conus medullaris and a neurologic deficit. This may be seen clinically in thoracolumbar fractures.

Robinson anterior cervical fusion comparison of the standard and modified techniques.

In 1990 the authors modified the Robinson anterior cervical interbody fusion technique by burring the endplates to expose subchondral bone. The authors compared 31 patients having the standard technique and 29 patients having the modified technique to evaluate 1) setting of the bone graft, 2) kyphotic angulation, 3) pseudarthrosis rate, and 4) pain outcome. In the standard Robinson fusion technique, the average loss of height across the fused segments was 0.8 mm and the average increase in kyphosis 4.9 degrees. Values for the modified technique were 1.9 mm and 3.1 degrees, respectively. The change in height was statistically significant (P = .01), as was the difference in angulation (P = .028), though the latter was in the opposite direction predicted. The pseudarthrosis rate using the modified technique decreased to 4.4% per level. Pain outcome for the two groups was equivalent. Burring of the endplates for anterior cervical interbody arthrodesis results in a detectable but not clinically important amount of graft settling with a higher success rate for arthrodesis.

Esophageal perforation after anterior cervical plate fixation: a report of two cases.

We report two cases of esophageal complications due to migration of screws after anterior plate fixation of the cervical spine. Close observation for screw back out is needed, particularly in those patients with associated neurologic deficits or osteoporosis.

Postoperative cerebrospinal-fluid fistula associated with erosion of the dura. Findings after anterior resection of ossification of the posterior longitudinal ligament in the cervical spine.

Of twenty-two patients who had had anterior decompression of the spinal canal for ossification of the posterior longitudinal ligament and cervical myelopathy, seven had absence of the dura adjacent to the ossified part of the ligament. The spinal cord and nerve-roots were visible through this defect. Although the arachnoid membrane appeared to be intact and watertight in most patients, a cerebrospinal-fluid fistula developed postoperatively in five, and three had a second operation to repair the defect in the dura. On the basis of this experience, we recommend use of autogenous muscle or fascial dural patches, immediate lumbar subarachnoid shunting, and modification of the usual postoperative regimen, such as limitation of mechanical pulmonary ventilation to the shortest time that is safely possible and use of anti-emetic and antitussive medications to protect the remaining coverings of the spinal cord when the dura is found to be absent adjacent to an ossified portion of the posterior longitudinal ligament in the cervical spine.

Mediastinal widening associated with fractures of the upper thoracic spine.

Widening of the mediastinum, when seen on radiographs of the chest in victims of trauma, is usually attributed to injury to the aorta. An aortic injury, when not lethal, often causes paraparesis or paraplegia due to ischemia of the spinal cord. A fracture of the upper thoracic spine can produce similar clinical and radiographic findings. The cases of three patients who had those findings are presented; in all three, the differential diagnosis between the vascular and skeletal injuries was difficult. Fracture of the thoracic spine should be included in the differential diagnosis whenever mediastinal widening is seen on radiographs.

Gd-DTPA enhancement of posterior epidural scar: an experimental model.

Because of the tremendous clinical and physiological importance of anterior epidural scar, an easily produced and reproducible model to assess potential pathways for lessening its formation is a necessity. We speculated whether posterior epidural scar (produced by the less complex surgery of laminectomy alone) could be considered equivalent to anterior scar from an imaging standpoint; that is, enhancement following Gd-DTPA irrespective of scar age. Posterior epidural scar in dogs showed the highest degree of enhancement 1 month after surgery, with a rapid decline thereafter out to 4 months postsurgery to a level equivalent to that of paraspinal muscle. Gd-153-DTPA time/activity curves paralleled the Gd-DTPA findings. Light microscopy showed granulation tissue after 1 month, and mature scar with large amounts of collagen 4 months after surgery. Electron microscopy showed tight capillary endothelial junctions. An appropriate model for epidural scar, which has imaging characteristics similar to human anterior scar, necessitates an extensive lumbar laminectomy with anterior epidural dissection. A simple laminectomy, while easily performed, does not provide a physiologically correct time course of enhancement.

Degenerative spondylolisthesis.

Degenerative spondylolisthesis is a unique form of spondylolisthesis that is characterized in most patients as a hypertrophic arthritis of the facet joint resulting in segmental instability predominantly in the sagittal plane. Disk degeneration is associated with degenerative spondylolisthesis to a varying degree. Joint involvement may not be uniform in all patients, and a rotary component, although small, is often present. The fourth to fifth lumbar level is most often involved, particularly in association with a relatively rigid lumbosacral segment. Degenerative spondylolisthesis is more common in females and in blacks, and it seldom occurs before the age of 40 years. Symptoms are generally due to lateral stenosis that compromises the inferior nerve roots, usually at the level of the fifth lumbar vertebra. However, the superior nerve roots can be compressed in more advanced cases. Neurogenic claudication and radiculopathy are commonly reported symptoms at the time a patient is first examined. The findings of physical examination vary; less than half of the patients examined exhibit a neurologic deficit. Rarely, a patient has cauda equina syndrome at the time of initial examination. Mild cases can be successfully treated surgically, but significant neurologic symptoms can only be diminished by adequate decompression. We recommend posterolateral fusion because of the deformity's propensity to progress postoperatively.

Immediate and delayed neurorrhaphy in a rabbit model: a functional, histologic, and biochemical comparison.

The effect of timing of neurorrhaphy on neuromuscular function was studied. The extensor digitorum longus neuromuscular units of 51 rabbits were used, with repairs performed immediately, 3 weeks, 3 months, and 6 months after nerve transection. Neuromuscular function was assessed 3 months after nerve repair, as was histology, histochemistry, and muscle hydroxyproline content. Force generated by immediately repaired units was 93% of unoperated controls. All functional delayed repairs produced approximately 50% of control force. Mild endomysial and perimysial fibrosis was present in the immediate neurorrhaphy group. Fibrosis was mild to moderate in the functional delayed repairs and moderate to severe in the nonfunctional repairs. Total and regional hydroxyproline content correlated to both function and timing of nerve repair. The data demonstrate that immediate repair of peripheral nerve lacerations gives the best functional recovery in this rabbit model. If immediate repairs are not performed in the rabbit, approximately 50% to 75% of normal function can be obtained when repairs are delayed for periods of 3 weeks to 6 months.

Tibial tubercle avulsions.

Avulsion of the tibial tubercle is not common. Sixteen cases are recorded, with a mean age of 15 years 2 months. All subjects were boys, 15 cases were left-sided, and three individuals had other associated knee injuries. All were treated operatively. Immobilization time averaged 4.9 weeks, with a mean follow-up of 15 months. Fourteen subjects regained full motion and activity. Three complications were noted, none of which was associated with this injury. This injury occurs in a vulnerable period when the physis is undergoing physiologic changes that weaken its ability to resist tensile loading.