Brett A. Taylor

Differences in the work-up and treatment of conditions associated with low back pain by patient gender and ethnic background.

Study Design. Retrospective review comparing physician workup of degenerative lumbosacral pathologies between different genders and ethnic groups. Objectives. To investigate whether patient ethnicity and gender influence the workup and treatment of degenerative spinal pathologies. Summary of Background Data. Data from numerous studies suggest that patient gender and ethnicity play a role in medical decision-making, with white males receiving more frequent interventions than women and minorities. Methods. Patients enrolled for an “initial visit” in the National Spine Network database with lumbosacral level degenerative diagnosis were reviewed. Variables included patient gender, ethnicity, age, duration of symptoms, patient-graded severity of symptoms, radicular symptom pattern, and work status. Results. We identified 5690 patients with degenerative lumbosacral pathologies. Although females were more likely than males to have imaging tests ordered, male (18.5%) patients were significantly more likely to have surgery recommended than female (16.3%) patients (P < 0.031). Nonwhite females were 52% less likely to have surgery offered at initial visit, as compared to white males (P < 0.005). More imaging tests were ordered or reviewed among whites (76.6%) than among any other ethnic group (P = 0.162). White (18.3%) and Asian (22.5%) patients were significantly more likely to have surgery recommended or prescribed than black (11.1%) and Hispanic (14.5) patients (P < 0.0001). Conclusions. This study suggests that ethnicity and gender affect the workup and surgical management of degenerative spinal disorders. However, it should be noted that there are a number of confounding factors not identified in the database, including managed care and insurance status and cultural differences, which may affect both test ordering and treatment recommendations. Further study of bias in clinical decision-making is indicated to assure equal delivery of quality care.

Cast immobilization versus percutaneous pin fixation of displaced distal radius fractures in children: a prospective, randomized study.

Thirty-four patients were enrolled in a prospective randomized study comparing cast immobilization alone versus percutaneous pin fixation following closed reduction of distal radial metaphyseal fractures. Patients older than 10 years of age with greater than 30 degrees of dorsal angulation or with complete fracture displacement were eligible for enrollment. Average follow-up was 10.5 weeks. All fractures healed uneventfully without deformity, growth arrest, or functional limitations. Overall complication rates were similar between groups. Thirty-nine percent of patients treated with casting had subsequent loss of reduction requiring remanipulation; there were no cases of loss of reduction in patients treated with pin fixation. Thirty-eight percent of patients treated with pin fixation had pin-related complications; all resolved following pin removal without long-term sequelae. Cost analysis showed no significant difference in treatment charges between groups. Treating surgeons should be aware of the potential short-term complications of each treatment method and adjust their postoperative care appropriately.

Correlation between low triggered electromyographic thresholds and lumbar pedicle screw malposition : Analysis of 4857 screws

Study Design. A retrospective analysis of 1078 spinal surgical procedures with lumbar pedicle screw placement at a single institution. Objective. Based on previously established normative values, triggered electromyographic stimulation (TrgEMG) was re-examined to evaluate its efficacy in determining screw malposition. Summary of Background Data. Threshold values for confirmation of intraosseous placement of pedicle screws with EMG stimulation is controversial. Methods. TrgEMG threshold values for 4857 pedicle screws placed from L2 to S1 from 1996 to 2005 were analyzed. An ascending method of constant current stimulation was applied to each pedicle screw to obtain a compound muscle action potential (CMAP) from lower extremity myotomes. Previously determined threshold value normative data from a published clinical series of 233 screws were as follows: 0 to 4 mA, high likelihood of pedicle wall breach; 4 to 8 mA, possible pedicle wall breach; >8 mA, no pedicle wall defect. Results. A total of 7.74% (376 of 4857) of all screws tested had threshold values <8.0 mA. A total of 19.1% (72 of 376) of these were <4.0 mA: 54% (39 of 72) were repositioned (26) or removed (13) while the remaining 33 screws were left in place following repalpation. A total of 80.9% (304 of 376) had thresholds between 4 and 8 mA: 17.4% (53) were repositioned (38) or removed (15). Nine screws had thresholds of ≤2.8 mA and were either repositioned or removed following confirmation of a medial wall breach. A total of 74.5% (280 of 376) of all screws with thresholds <8.0 mA were verified as correctly placed by repalpation/radiography and therefore left in place. Conclusion. The probability of a medial breach pedicle screw detected by triggered EMG stimulation increases with decreasing triggered EMG thresholds: 0.31% for >8.0 mA, 17.4% for 4.0 to 8.0 mA, 54.2% for <4.0 mA, and 100% for <2.8 mA. At 2.8 mA, triggered EMG has a specificity of 100%, with sensitivity of 8.4%; at 4.0 mA, specificity of 99% and sensitivity of 36%; and at 8.0 mA, 94% specificity and 86% sensitivity. TrgEMG is an adjuncttechnique and should always be used in conjunction with palpation and radiography to optimize safe pedicle screw placement.

Biomechanical assessment of a PEEK rod system for semi-rigid fixation of lumbar fusion constructs.

The concept of semi-rigid fixation (SRF) has driven the development of spinal implants that utilize nonmetallic materials and novel rod geometries in an effort to promote fusion via a balance of stability, intra- and inter-level load sharing, and durability. The purpose of this study was to characterize the mechanical and biomechanical properties of a pedicle screw-based polyetheretherketone (PEEK) SRF system for the lumbar spine to compare its kinematic, structural, and durability performance profile against that of traditional lumbar fusion systems. Performance of the SRF system was characterized using a validated spectrum of experimental, computational, and in vitro testing. Finite element models were first used to optimize the size and shape of the polymeric rods and bound their performance parameters. Subsequently, benchtop tests determined the static and dynamic performance threshold of PEEK rods in relevant loading modes (flexion-extension (F/E), axial rotation (AR), and lateral bending (LB)). Numerical analyses evaluated the amount of anteroposterior column load sharing provided by both metallic and PEEK rods. Finally, a cadaveric spine simulator was used to determine the level of stability that PEEK rods provide. Under physiological loading conditions, a 6.35 mm nominal diameter oval PEEK rod construct unloads the bone-screw interface and increases anterior column load (approx. 75% anterior, 25% posterior) when compared to titanium (Ti) rod constructs. The PEEK constructs stiffness demonstrated a value lower than that of all the metallic rod systems, regardless of diameter or metallic composition (78% < 5.5 mm Ti; 66% < 4.5 mm Ti; 38% < 3.6 mm Ti). The endurance limit of the PEEK construct was comparable to that of clinically successful metallic rod systems (135N at 5 × 10(6) cycles). Compared to the intact state, cadaveric spines implanted with PEEK constructs demonstrated a significant reduction of range of motion in all three loading directions (> 80% reduction in F/E, p < 0.001; > 70% reduction in LB, p < 0.001; > 54% reduction in AR, p < 0.001). There was no statistically significant difference in the stability provided by the PEEK rods and titanium rods in any mode (p = 0.769 for F/E; p = 0.085 for LB; p = 0.633 for AR). The CD HORIZON(®) LEGACY(™) PEEK Rod System provided intervertebral stability comparable to currently marketed titanium lumbar fusion constructs. PEEK rods also more closely approximated the physiologic anteroposterior column load sharing compared to results with titanium rods. The durability, stability, strength, and biomechanical profile of PEEK rods were demonstrated and the potential advantages of SRF were highlighted.

Racial Variation in Treatment Preferences and Willingness to Randomize in the Spine Patient Outcomes Research Trial (SPORT)

Study Design. Analysis of baseline data for patients enrolled in Spine Patient Outcomes Research Trial (SPORT), a project conducting three randomized and three observational cohort studies of surgical and nonoperative treatments for intervertebral disc herniation (IDH), spinal stenosis (SpS), and degenerative spondylolisthesis (DS). Objective. To explore racial variation in treatment preferences and willingness to be randomized. Summary of Background Data. Increasing minority participation in research has been a priority at the NIH. Prior studies have documented lower rates of participation in research and preferences for invasive treatment among African-Americans. Methods. Patients enrolled in SPORT (March 2000 to February 2005) that reported data on their race (n = 2,323) were classified as White (87%), Black (8%), or Other (5%). Treatment preferences (nonoperative, unsure, surgical), and willingness to be randomized were compared among these groups while controlling for baseline differences using multivariate logistic regression. Results. There were numerous significant differences in baseline characteristics among the racial groups. Following adjustment for these differences, Blacks remained less likely to prefer surgical treatment among both IDH (White, 55%; Black, 37%; Other, 55%, P = 0.023) and SpS/DS (White, 46%; Black, 30%; Other, 43%; P = 0.017) patients. Higher randomization rates among Black IDH patients (46% vs. 30%) were no longer significant following adjustment (odds ratio [OR] = 1.45, P = 0.235). Treatment preference remained a strong independent predictor of randomization in multivariate analyses for both IDH (unsure OR = 3.88, P < 0.001 and surgical OR = 0.23, P < 0.001) and SpS/DS (unsure OR = 6.93, P < 0.001 and surgical OR = 0.45, P < 0.001) patients. Conclusions. Similar to prior studies, Black participants were less likely than Whites or Others to prefer surgical treatment; however, they were no less likely to agree to be randomized. Treatment preferences were strongly related to both race and willingness to be randomized.

Detection of Esophageal Perforation Using Intraesophageal Dye Injection

Objectives Esophageal perforation complicating anterior cervical spine surgery is a potentially fatal complication. Early identification and immediate treatment may lower adverse effects for the patient. The purpose of this study is to assess the efficacy of intraesophageal dye injection to detect an esophageal injury and to test two novel techniques. Method Ten cadaveric specimens were dissected using an anteromedial Smith–Robinson approach. Each was sequentially tested by a control and three dye injection techniques: technique A: nasogastric tube alone; technique B: nasogastric tube plus a distally placed Foley catheter; technique C: proximal plus a distally placed Foley catheter. Each technique was tested against esophageal perforations created by needle puncture (21-gauge, 18-gauge, and 14-gauge) and by a 2-mm high-speed burr. Dye visualization was independently graded as present or absent by two authors. Results In the control trial, no dye leak was visualized in any of the 10 specimens. In technique A, 0 of 10 21-gauge perforations, 1 of 10 18-gauge perforations, 2 of 10 14-gauge perforations, and 6 of 10 burr perforations were visualized. In technique B, 1 of 10 21-gauge perforations, 8 of 10 18-gauge perforations, 9 of 10 14-gauge perforations, and 9 of 10 burr perforations were visualized. In technique C, 0 of 10 21-gauge perforations, 9 of 10 18-gauge perforations, 10 of 10 14-gauge perforations, and 7 of 10 burr perforations were visualized. Conclusions The study suggests that intraesophageal dye injection via nasogastric tube alone should not be relied upon to exclude the presence of esophageal perforation. Two novel techniques showed an improved, though limited, capability of detecting esophageal perforations.

The risk of foraminal violation and nerve root impingement after anterior placement of lumbar interbody fusion cages.

Study Design. Three groups of six embalmed cadaver spines underwent placement of lumbar interbody fusion cages centered either at midline, 10% lateral of midline, or 20% lateral of midline. The spines were evaluated for evidence of neuroforamen violation or nerve root impingement. Objectives. To determine the potential for foraminal violation or nerve root impingement after correct placement and lateral misplacement of lumbar interbody fusion cages. Summary of Background Data. Radicular symptoms after anterior cage placement have raised some concern about the potential for inadvertent device-related foraminal violation not adequately appreciated by intraoperative fluoroscopy. Methods. Preoperative computed tomography scanning and plain radiography was used to measure endplate dimensions at L4–L5 and to template the appropriately sized interbody fusion cages. The cadaveric specimens were randomly divided into three groups of six (Groups I–III) and instrumented at L4–L5 either at midline (I) or 10% (II) or 20% (III) lateral of midline. Postoperative computed tomography and plain radiography was evaluated for evidence of neuroforamen violation, followed by dissection of the specimens. Results. Foraminal violation occurred in one of six spines in group II (10% off midline) and in three of six spines in group III (20% off midline). Two of the three cadavers in group III with foraminal violation also were noted to have nerve root abutment on computed tomography scans and spinal dissection. Conclusions. Excessive lateral placement of lumbar interbody fusion cages may result in foraminal violation and possible nerve encroachment. The “safe zone” for centering the cages extends approximately 5 mm on either side of midline.

Anterior Corpectomy or Multilevel Discectomy

The purpose of this article is to review the application of two techniques in the treatment of multilevel cervical spondylosis. Multiple level anterior cervical discectomy fusion (ACDF) and cervical corpectomies are effective for decompression and stabilization of the spondylitic spine. Each operation has advantages and drawbacks though, and appropriate patient selection is critical to successful outcome while minimizing complications. This review examines the perils of the anterior cervical approach and the indications and controversies of multiple ACDFs versus corpectomy. An overview of our most updated techniques for both operations is also presented.

Use of an Osteocutaneous Plantar Free Flap for Salvage of a Below-the-Knee Amputation in a Child A CASE REPORT*

We report the results of a transplantation of a free flap that included the vascularized calcaneus and associated soft tissues in an attempt to obtain greater function after a below-the-knee amputation by providing sensate skin for prosthetic weight-bearing. An eleven-year-old boy slipped and fell while trying to board a slow-moving train. The left leg was caught in the train tracks, and the train continued to move over it. He was taken to a nearby hospital for initial evaluation and then was transferred to our institution. The initial duration of ischemia was six hours. He had a devascularizing and degloving injury of the leg, which was rotated 360 degrees, was cold, was without a pulse, and was without motor function distal to the knee. There was only a six-millimeter-wide flap of dorsal skin attaching the knee to the foot. There was a segmental defect of muscle, bone, and neurovascular tissue that extended from the proximal to the distal tibial metaphysis. The tibia and the fibula were completely shattered. The zone of injury to the skin extended to the level of the distal femoral metaphysis. There were no associated injuries, and the patient was hemodynamically stable. He had a history of melorheostosis for which he had had a quadricepsplasty to improve flexion of the knee. The severe segmental defects of soft tissue and bone made replantation impossible and amputation inevitable. We decided to salvage the extremity by creating a below-the-knee amputation stump that would permit weight-bearing and preserve the extensor mechanism. A microvascular free flap was fashioned, with use of the plantar skin, the …