William J. Richardson

The Impact of Surgical-Site Infections Following Orthopedic Surgery at a Community Hospital and a University Hospital Adverse Quality of Life, Excess Length of Stay, and Extra Cost

OBJECTIVE To measure the impact of orthopedic surgical-site infections (SSIs) on quality of life, length of hospitalization, and cost. DESIGN A pairwise-matched (1:1) case-control study within a cohort. SETTING A tertiary-care university medical center and a community hospital. PATIENTS Cases of orthopedic SSIs were prospectively identified by infection control professionals. Matched controls were selected from the entire cohort of patients undergoing orthopedic surgery who did not have an SSI. Matching variables included type of surgical procedure, National Nosocomial Infections Surveillance risk index, age, date of surgery, and surgeon. MAIN OUTCOME MEASURES Quality of life, duration of postoperative hospital stay, frequency of hospital readmission, overall direct medical costs, and mortality rate. RESULTS Fifty-nine SSIs were identified. Each orthopedic SSI accounted for a median of 1 extra day of stay during the initial hospitalization (P = .001) and a median of 14 extra days of hospitalization during the follow-up period (P = .0001). Patients with SSI required more rehospitalizations (median, 2 vs 1; P = .0001) and more total surgical procedures (median, 2 vs 1; P = .0001). The median total direct cost of hospitalizations per infected patient was

Standard scales for measurement of functional outcome for cervical pain or dysfunction: A systematic review

24,344, compared with

Reliability, validity, and responsiveness of the short form 12-item survey (SF-12) in patients with back pain.

6,636 per uninfected patient (P = .0001). Mortality rates were similar for cases and controls. Quality of life was adversely affected for patients with SSI. The largest decrements in scores on the Medical Outcome Study Short Form 36 questionnaire were seen in the physical functioning and role-physical domains. CONCLUSIONS Orthopedic SSIs prolong total hospital stays by a median of 2 weeks per patient, approximately double rehospitalization rates, and increase healthcare costs by more than 300%. Moreover, patients with orthopedic SSIs have substantially greater physical limitations and significant reductions in their health-related quality of life.

The Cervical Facet Capsule and Its Role in Whiplash Injury : A Biomechanical Investigation

Study Design. A systematic review was conducted. Objective. To identify, evaluate, and compare standard scales for assessing neck pain or dysfunction. Summary of Background Data. The degree of a patient’s neck pain or dysfunction can be evaluated using standardized scales at the time of a clinical encounter or during the performance of clinical research protocols. The choice of a scale with the most appropriate characteristics, however, is always a challenge to clinicians and researchers. Methods. Articles concerning scales for functional evaluation of neck pain or dysfunction were identified by computer searching of MEDLINE (January 1966 to June 1999) and CINAHL (1985 to 2000), citation tracking using the Citation Index, hand searching of relevant journals, and correspondence with experts. Results. Five standard scales were found. Three scales were remarkably similar in terms of structure and psychometric properties: the Neck Disability Index, the Copenhagen Neck Functional Disability Scale, and the Northwick Park Scale. However, only the first instrument has been revalidated in different study populations. The Neck Pain and Disability Scale provides a visual template for collection of information, but its usefulness is limited if the questionnaire must be read to the patient. The Patient-Specific Functional Scale is very sensitive to functional changes in individual patients, but comparisons between patients are virtually impossible. Conclusions. The five scales identified in this study have similar characteristics. The Neck Disability Index, however, has been revalidated more times for evaluation of patient groups. For individual patient follow-up evaluation, the Patient-Specific Functional Scale has high sensitivity to change, and thus represents a good choice for clinical use. The final choice should be tailored according to the target population and the purpose of the evaluation.

Dynamic responses of the head and cervical spine to axial impact loading

Study Design. Secondary analysis of data collected from spine patients’ normal clinic visits from 1998 to 2001. Objective. To evaluate the reliability, validity, and responsiveness of the short form 12-item survey in patients with back pain. Summary of Background Data. The reliability, validity, and responsiveness of the short form 12-item survey in patients with back pain has not been previously evaluated. Methods. Patients were asked to complete a comprehensive computerized survey questionnaire during their regular clinic visits. A total of 2520 patients who indicated in their first surveys that they had back pain were included in the study of the reliability and validity of the short form 12-item survey. Of these, 506 patients completed another survey within 3–6 months of follow-up and were included in the responsiveness evaluation. Results. The two summary scales of the short form 12-item survey, physical component summary and mental component summary, demonstrated internal consistency reliability, with Cronbach alpha for both scales exceeding the recommended level of 0.70. Correlation of physical component summary and mental component summary with six other measures theoretically related or unrelated to these scales performed as expected without exception, demonstrating the construct validity of the short form 12-item survey. The responsiveness of the short form 12-item survey was supported by several pieces of evidence. First, the changes in physical component summary and mental component summary scores were correlated with the changes in back pain intensity. Second, for patients whose back pain improved, there was a significant increase in the follow-up physical component summary and mental component summary scores as compared to the baseline. Third, small to moderate effect size was observed for patients whose back pain became improved or became worse. Conclusions. The short form 12-item survey demonstrated good internal consistency reliability, construct validity, and responsiveness in patients with back pain.

Combined single stage anterior and posterior osteotomy for correction of iatrogenic lumbar kyphosis.

STUDY DESIGN Cervical facet capsular strains were determined during bending and at failure in the human cadaver. OBJECTIVE To determine the effect of an axial pretorque on facet capsular strains and estimate the risk for subcatastrophic capsular injury during normal bending motions. SUMMARY OF BACKGROUND DATA Epidemiologic and clinical studies have identified the facet capsule as a potential site of injury and prerotation as a risk factor for whiplash injury. Unfortunately, biomechanical data on the cervical facet capsule and its role in whiplash injury are not available. METHODS Cervical spine motion segments were tested in a pure-moment test frame and the full-field strains determined throughout the facet capsule. Motion segments were tested with and without a pretorque in pure bending. The isolated facet was then elongated to failure. Maximum principal strains during bending were compared with failure strains, by paired t test. RESULTS Statistically significant increases in principal capsular strains during flexion-extension loading were observed when a pretorque was applied. All measured strains during bending were significantly less than strains at catastrophic joint failure. The same was true for subcatastrophic ligament failure strains, except in the presence of a pretorque. CONCLUSIONS Pretorque of the head and neck increases facet capsular strains, supporting its role in the whiplash mechanism. Although the facet capsule does not appear to be at risk for gross injury during normal bending motions, a small portion of the population may be at risk for subcatastrophic injury.

Diabetes and early postoperative outcomes following lumbar fusion.

This study explores the inertial effects of the head and torso on cervical spine dynamics with the specific goal of determining whether the head mass can provide a constraining cervical spine end condition. The hypothesis was tested using a low friction impact surface and a pocketing foam impact surface. Impact orientation was also varied. Tests were conducted on whole unembalmed heads and cervical spines using a drop track system to produce impact velocities on the order of 3.2 m s-1. Data for the head impact forces and the reactions at T1 were recorded and the tests were also imaged at 1000 frames s-1. Injuries occurred 2-19 ms following head impact and prior to significant head motion. Average compressive load a failure was 1727 +/- 387 N. Decoupling was observed between the head and T1. Cervical spine loading due to head rebound constituted up to 54 +/- 16% of the total axial neck load for padded impacts and up to 38 +/- 30% of the total axial neck load for rigid impacts. Dynamic buckling was also observed; including first-order modes and transient higher-order modes which shifted the structure from a primarily compressive mode of deformation to various bending modes. These experiments demonstrate that in the absence of head pocketing, the head mass can provide sufficient constraint to cause cervical spine injury. The results also show that cervical spinal injury dynamics are complex, and that a large sample size of experimentally produced injuries will be necessary to develop comprehensive neck injury models and criteria.

SURGICAL MANAGEMENT OF METASTATIC RENAL CARCINOMA OF THE SPINE

Fifty-four patients were treated by a standardized single stage anterior opening wedge and a posterior closing extension wedge osteotomy for back pain associated with postoperative loss of lumbar lordosis (iatrogenic flat back syndrome). Presenting complaints were fatigue, pain and a stooped posture. Etiological factors were, in descending order of frequency, distraction instrumentation with the lower end at the L5 or S1 vertebra, thoracolumbar junction kyphosis greater than 15°, especially if associated with a hypokyphotic thoracic spine, and degenerative changes above and below a previous fusion. Kostuik-Harrington Instrumentation was used anteriorly for the opening wedge and Dwyer cables and screws together with a midline plate were used posteriorly for the closing extension osteotomy. Malunion occurred in three patients, one requiring recorrection. Pain relief occurred in 48 (90%). Neurological complications occurred in two patients, one with permanent deficient. Follow-up averaged 4 years. Average preosteotomy lordosis L1–S1 was 21.5° and was restored to 49° (equal to the lordosis before the initial surgery) for an average correction of 29°, (range 24° to 63°). Prevention of this complication can be accomplished by maintaining normal lordosis at the time of initial surgery

Experimental impact injury to the cervical spine: relating motion of the head and the mechanism of injury.

Study Design. Retrospective cohort study using data from the Nationwide Inpatient Sample administrative data from 1988 through 2003. Objective. To examine perioperative morbidity and mortality for patients with and without diabetes mellitus following lumbar spinal fusion. Summary of Background Data. Diabetes has been associated with worse outcomes in a variety of orthopedic procedures including spinal surgery. There is limited evidence that diabetic patients have more complications following lumbar fusion with little published data to support this conclusion. Methods. Data from 197,461 patients who underwent lumbar fusion were included. Over 11,000 patients (5.6%) with a postoperative diagnosis of diabetes mellitus were identified. Selected variables were used for comparison of patients with and without diabetes. Bivariate statistical analyses compared postoperative complication rates while multivariate statistics were used to determine likelihood of complications with diabetes. Results. Bivariate analysis demonstrated that diabetes was significantly associated with postoperative infection, need for transfusion, pneumonia, in-hospital mortality, and nonroutine discharge (P ≤ 0.001). Adjusted multivariate regression analyses, however, suggested no difference in mortality although infection, transfusion, and nonroutine discharge continued to be highly significant (P ≤ 0.002). Significantly higher inflation adjusted total charges were also present with patients with diabetes as well as increased lengths of stay (P < 0.001). Conclusion. This nationally representative study of inpatients in the United States provides evidence that diabetes is associated with increased risk for postoperative complications, nonroutine discharge, increased total hospital charges, and length of stay following lumbar fusion. Prospective studies to determine causality as well as the potential impact of diabetes control on these variables have not yet been done.

Comparative strengths and structural properties of the upper and lower cervical spine in flexion and extension

A total of 33 patients with renal cell carcinoma metastatic to the spine underwent spinal decompression over a 5-year period; 20 were operated on for neurologic dysfunction, and the remainder for pain alone. Surgery was performed anteriorly in 21, posteriorly in 9, and combined in 3 cases. The surgical approach was determined by the preoperative anatomic localization of the tumor. Of these patients 88% had fusions with instrumentation and polymethylmethacrylate; 88% of patients had partial or complete relief of pain; and 64% of bedridden patients subsequently were able to walk. Neurologic function improved in 60% of patients with a neurologic deficit; however, only 36% of incontinent patients regained bladder control. Survival averaged 8.0 ± 1.5 months. Survival correlated with the degree of neurologic dysfunction and the presence of other known metastases. Recurrent cord compression developed in 49% of patients, usually at the same level; 9 of these 16 patients had repeat decompression, with similar operative results as the primary procedure in terms of pain and neurologic function. Blood loss was variable but often significant. Preoperative embolization appeared to be beneficial. Precise tumor localization preoperatively directing the surgical approach and better patient selection would likely improve results and decrease morbidity. Good palliation appeared to be achieved in regards to both pain relief and improved neurologic function.