Joel A. Finkelstein

Insertional torque and pull-out strengths of conical and cylindrical pedicle screws in cadaveric bone.

Study Design. Insertion torque and pull‐out strengths of conical and cylindrical pedicle screws were compared in human cadaveric vertebral bodies. Objectives. To compare the performance of the conical design with the cylindrical design, and to determine whether insertional torque correlates with pull‐out strength. Summary of Background Data. A tapered pedicle screw design may lessen the likelihood of implant failure. Its effect on thread purchase is not known. Previous studies of cylindrical designs on the relation between insertion torque and pull‐out strength have been conducted in bovine and synthetic bone. Methods. Seventy‐eight pedicles were assigned randomly to one of the following pedicle screw: Texas Scottish Rite Hospital (Sofamor‐Danek, Memphis, TN), Steffee VSP (Acromed, Cleveland, OH), Diapason (Dimso, Paris, France), AO Schanz (Synthes, Paoli, PA), or Synthes USS (Synthes, Paoli, PA). Pedicle screws were inserted with a torque screwdriver. Each screw was extracted axially from the pedicle at a rate of 1.0 mm/sec until failure using an MTS machine (Bionix 858, Minneapolis, MN). Force data were recorded. Results. The conical design had the highest insertion torque. There were no significant differences in pull‐out between any of the screw types. Correlation between insertional torque and pull‐out strength was statistically significant only with the Texas Scottish Rite Hospital and Steffee VSP in L4 and AO Schanz in L5. Conclusions. A conical screw profile increases insertion torque, although insertional torque is not a reliable predictor of pull‐out strength in cadaveric bone. Screw profile (with similar dimensions) has little effect on straight axial pull‐out strengths in cadaveric bone.

Varus Osteotomy of the Distal Part of the Femur. A Survivorship Analysis

Varus osteotomy of the distal part of the femur is often the procedure of choice for the treatment of osteoarthrosis of the lateral compartment associated with genu valgum. We followed twenty-one knees (twenty patients) long term or until failure. At the most recent evaluation (average, 133 months; range, ninety-seven to 240 months), thirteen osteotomies were still successful, seven had failed, and one patient (in whom the knee had remained functional) had died. Of the seven failures, three occurred early (at twelve or twenty-four months) and four occurred late (between seventy-two and ninety-eight months). The probability of survival at ten years was 64 per cent (95 per cent confidence interval, 48 to 80 per cent), as determined with use of the Kaplan-Meier method. We concluded that, with proper selection of patients, this procedure is effective for the treatment of gonarthrosis of the lateral compartment associated with valgus deformity.

Quality of life in surgical treatment of metastatic spine disease

Study Design. Overall quality of life after surgical management of metastatic disease of the spine was prospectively assessed using a validated global health status quality-of-life instrument—the Edmonton Symptom Assessment Scale. Objectives. To prospectively evaluate the efficacy of surgery in patients with metastatic spinal disease with respect to quality of life. Summary of Background Data. Management of spinal metastases is palliative and is aimed at improving quality of life at an acceptable risk. Although previous studies have evaluated physical outcomes, improvements in pain, and neurologic function after surgery, a multidimensional assessment of quality of life is more relevant in the palliative patient. Methods. Twenty-five consecutive patients undergoing surgery for spinal metastases were prospectively evaluated. Pre- and postoperative assessments were performed using the Edmonton Symptom Assessment Scale. The surgical procedure consisted of decompression and instrumented stabilization. Results. After surgery, the largest improvement was noted in the domain of pain (P < 0.00001). There were also significant improvements noted in the domains of tiredness (P = 0.004), nausea (P = 0.01), anxiety (P = 0.006), drowsiness (P = 0.044), appetite (P = 0.02), and well-being (P = 0.004). Conclusions. The current study demonstrates that in the appropriate patient, surgical management brings about a positive effect on the overall quality of life in patients with spinal metastases. The greatest benefit occurred in the reduction of a patient’s level of pain.

Traditional assessment of health outcome following total knee arthroplasty was confounded by response shift phenomenon.

OBJECTIVES To examine the existence, direction, and effect of response shift as measured by the total score of Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and SF-36 physical and mental component score domains at 6 months and 1 year after primary total knee arthroplasty (TKA). STUDY DESIGN AND SETTING Consecutive candidates participated in the study. In line with the Then-test design, two sets of questionnaires were completed at 6 months and 1 year postoperatively. Patients were divided into three groups on the basis of minimal clinically important differences (MCIDs). Parametric and nonparametric statistics and generalized mixed effects models were used. RESULTS Two hundred and thirty-six patients completed the study. The magnitude of response shift increased over time for SF-36 physical and mental component scores. The traditional unadjusted presurgical and 1-year postsurgical assessment failed to reveal any mental health improvement, whereas the adjusted treatment effect demonstrated statistically significant changes. CONCLUSION Response shift phenomenon increases with time in patients undergoing orthopedic interventions. The traditional pre- and post-assessment of joint replacement surgery may be confounded by a change in perspective and in internal standards of measurement in patients undergoing surgery. Response shift has substantial impact on measuring recovery in this population.

Early Retropulsion of Titanium-Threaded Cages After Posterior Lumbar Interbody Fusion : A Report of Two Cases

Study Design. Two patients had postoperative posterior migration of titanium fusion cages after posterior lumbar interbody fusion. They underwent a repeat posterior procedure and posterior fusion with pedicle screws. Objective. To suggest a treatment for posterior migration of titanium-threaded cages causing spinal stenosis after posterior lumbar interbody fusion. Summary of Background Data. The use of titanium fusion cages in posterior lumbar interbody fusion is gaining popularity as a technique for arthrodesis. The literature contains only a few reports concerning complications associated with their use. Methods. Two patients had retropulsion of titanium threaded cages, ten days and 2 months after posterior lumbar interbody fusion. The retropulsed cages compressing the dura, caused sudden onset of back pain and radiating pain to the lower extremities. Both patients underwent repeat posterior procedure that included repositioning of the cages and posterior fusion with pedicle screws. Results. Symptoms of back and leg pain subsided after repositioning of the cages and application of the pedicle screws. Conclusions. A repeat posterior approach and repositioning of the retropulsed titanium fusion cages in addition to posterior fusion with pedicle screws successfully managed this complication.

Single-level fixation of flexion distraction injuries

Flexion distraction injuries of the thoracic and lumbar spine can be stabilized with a short construct spanning one motion segment. This surgical technique has not been well accepted because of the paucity of published outcomes of patients treated in this manner. The current study is a cohort of patients who underwent a standardized posterior open reduction and single-level fixation for this injury pattern. Independent observation prospectively followed the cohort for a minimum of 20 months with functional and radiologic outcomes determined. A significant (p < 0.0001) correction of deformity was achieved, from a mean preoperative kyphosis of 10.1° to a mean postoperative lordosis of 0.9°. No loss of correction occurred. The mean Oswestry score was 11.5, with 88% of patients having minimal disability. This prospective study demonstrates the efficacy of posterior open reduction and single-level fixation of flexion distraction injuries.

Postoperative improvement in health-related quality of life: a national comparison of surgical treatment for focal (one- to two-level) lumbar spinal stenosis compared with total joint arthroplasty for osteoarthritis

BACKGROUND CONTEXT The results of single-center studies have shown that surgical intervention for lumbar spinal stenosis yielded comparable health-related quality of life (HRQoL) improvement to total joint arthroplasty (TJA). Whether these results are generalizable to routine clinical practice in Canada is unknown. PURPOSE The primary purpose of this equivalence study was to compare the relative improvement in physical HRQoL after surgery for focal lumbar spinal stenosis (FLSS) compared with TJA for hip and knee osteoarthritis (OA) across six Canadian centers. STUDY DESIGN/SETTING A Canadian multicenter ambispective cohort study. PATIENT SAMPLE A cohort of 371 primary one- to two-level spinal decompression (n=214 with instrumented fusion) for FLSS (n=179 with degenerative lumbar spondylolisthesis [DLS]) was compared with a cohort of primary total hip (n=156) and knee (n=208) arthroplasty for OA. OUTCOME MEASURES The primary outcome was the change in preoperative to 2-year postoperative 36-Item Short Form Health Survey Physical Component Summary (PCS) score as reflected by the number of patients reaching minimal clinically important difference (MCID) and substantial clinical benefit (SCB). METHODS Univariate analyses were conducted to identify baseline differences and factors that were significantly related to outcomes at 2 years. Multivariable regression modeling was used as our primary analysis to compare outcomes between groups. RESULTS The mean age (years) and percent females for the spine, hip, and knee groups were 63.3/58.5, 66.0/46.9, and 65.8/64.3, respectively. All three groups experienced significant improvement of baseline PCS (p<.001). Multivariate analyses, adjusting for baseline differences (age, gender, baseline Mental Component Summary score, baseline PCS), demonstrated no significant differences in PCS outcome between spinal surgery and arthroplasty (combined hip and knee cohorts) patients with an odds ratio of 0.80 (95% confidence interval [CI], 0.57-1.11; p=.17) and 0.79 (95% CI, 0.58-1.09; p=.15) for achieving MCID or SCB, respectively. In subgroup analysis, spine and knee outcomes were not significantly different, with hip arthroplasty superior to both (p<.0001). CONCLUSIONS Significant improvement in physical HRQoL after surgical treatment of FLSS (including DLS) is consistently achieved nationally. Our overall results demonstrate that a comparable number of patients can expect to achieve MCID and SCB 2 years after surgical intervention for FLSS and total knee arthroplasty.

Thrombosis of the axillary artery secondary to compression by the pectoralis minor muscle.

This case presentation reports the second case of axillary artery thrombosis secondary to pectoralis minor compression. Evidence to explain this etiology is presented from arteriographic and intraoperative clinical findings. Management includes division of the pectoralis minor muscle and local arterial repair if the vessel is severely damaged.

Optimization of tumor volume reduction and cement augmentation in percutaneous vertebroplasty for prophylactic treatment of spinal metastases.

Objective Spinal metastatic disease occurs in up to one-third of all cancer patients. Metastasis can lead to vertebral burst fracture and consequent neurologic compromise. Percutaneous vertebroplasty (PV) is a minimally invasive procedure aimed at restoring vertebral stability by augmentation of weakened vertebrae with bone cement. PV is associated with a complication rate of 10% in treating vertebral metastases. Tumor ablation before cement injection has been suggested to improve PV outcome in the metastatic spine. The objectives of this study were to quantify the effects of volumetric tumor reduction and cement augmentation in the metastatic spine and to develop a protocol for recommended cement volume to achieve sufficient restoration of intact (nonpathologic) vertebral body stability. Methods A biphasic parametric finite element model of an L1 spinal motion segment was developed and validated against previously collected experimental data. Using this model, 12 scenarios were simulated to represent tumor volume reductions of up to 60% and cement augmentation from 1 to 8 mL. Conclusions Restoration of intact vertebral stability is possible in metastatic vertebrae after 30% tumor ablation and 1 to 2 mL bone cement augmentation. A protocol was developed on the basis of the findings of this study suggesting recommended cement volume for injection as a function of remaining tumor volume after ablation. These findings may motivate refined methods of prophylactic treatment of metastatic vertebrae.

Physical rehabilitation of the critically ill trauma patient in the ICU.

Objectives:To 1) review the existing evidence for early mobilization of the critically ill patients in the ICU with polytrauma; 2) provide intensivists with an introduction to the biomechanics, physiology, and nomenclature of injuries; 3) summarize the evidence for early mobilization in each anatomic area; and 4) provide recommendations for the mobilization of these patients. Data Sources:A literature search of the MEDLINE and EMBASE databases for articles published in English between 1980 and 2011. Study Selection:Studies pertaining to physical therapy and rehabilitation in trauma patients were selected. Articles were excluded if they dealt with pediatrics, geriatrics, burn injuries, isolated hand injuries, chronic (i.e., not acute) injuries, nontraumatic conditions, and pressure/decubitus ulcers, were in a language other than English, were published only in abstract form, were letters to the editor, were case reports, or were published prior to 1980. Data Extraction:Reviewers extracted data and summarized results according to anatomical areas. Data Synthesis:Of 1,411 titles and abstracts, 103 met inclusion criteria. We found no articles specifically addressing the rehabilitation of polytrauma patients in the ICU setting or patients with polytrauma in general. We summarized the articles addressing the role of mobilization for specific injuries and treatments. We used this evidence, in combination with biologic rationale and physician and surgeon experience and expertise, to summarize the important considerations when providing physical therapy to these patients in the ICU setting. Conclusions:There is a paucity of evidence addressing the role of early mobilization of ICU patients with polytrauma and patients with polytrauma in general. Evidence for the beneficial role of early mobilization of specific injuries exists. Important considerations when applying a strategy of early physical therapy and mobilization to this distinctive patient group are summarized.