Jacob M. Drew

Use of the trauma pelvic orthotic device (T-POD) for provisional stabilisation of anterior-posterior compression type pelvic fractures: a cadaveric study.

OBJECTIVE To demonstrate that a commercially available pelvic binder the trauma pelvic orthotic device (T-POD) is an effective way to provisionally stabilise anterior-posterior compression type pelvic injuries. METHODS Rotationally unstable pelvic injuries were created in 12 non-embalmed human cadaveric specimens. Each pelvis was then stabilised first with a standard bed sheet wrapped circumferentially around the pelvis and held in place with a clamp. After recreating the symphyseal diastasis, the pelvis was stabilised with the T-POD. Reduction of the symphyseal diastasis was assessed by comparing measurements obtained via pre- and post-stabilisation AP radiographs. RESULTS The mean symphyseal diastasis was reduced from 39.3mm (95% CI 30.95-47.55) to 17.4mm (95% CI -0.14 to 34.98) with the bed sheet, and to 7.1mm (95% CI -2.19 to 16.35) with the T-POD. CONCLUSIONS Although both a circumferential sheet and the T-POD were able to decrease symphyseal diastasis consistently, only the T-POD showed a statistically significant improvement in diastasis when compared to injury measurements. In 75% of the cadaveric specimens (9 of 12), the T-POD was able to reduce the symphysis to normal (<10mm diastasis). Both a circumferential sheet and the T-POD are effective in provisionally stabilising Burgess and Young anterior-posterior compression II type pelvic injuries, but the T-POD is more effective in reducing symphyseal diastasis.

Vertebral Artery Anatomy : A Review of Two Hundred Fifty Magnetic Resonance Imaging Scans

Study Design. The aim of this study is to characterize the anatomy of vertebral arteries using magnetic resonance imaging scans of 250 consecutive patients. Objectives. To document the prevalence of midline vertebral artery (VA) migration in a subgroup of patients presenting with neck pain, radiculopathy, or myelopathy and to identify the course of the VA through the TFs. Summary of Background Data. Knowledge of VA anomalies and their respective prevalence may help surgeons decrease the incidence of iatrogenic injury to this artery. Methods. In this retrospective review of 281 consecutive patients, who had an magnetic resonance imaging for axial neck pain, radiculopathy, or myelopathy, anatomic measurements were obtained from C2 to C7. Results. The observed VA anomalies can be classified into following 3 main groups: (1) intraforaminal anomalies-midline migration, (2) extraforaminal anomalies, and (3) arterial anomalies. Midline migration of the VA was identified in 7.6% (19/250) of patients. The etiology can be degenerative or traumatic. It is important to note that the pattern of medial migration was clockwise rotation from caudal to cephalad and was present in all of our patients with anomalous arteries. Additionally, at C6, only 92% (460/500) of VAs were located within their respective transverse foramens and hypoplastic VAs were identified in 10% (25/250) of patients. Conclusion. Anomalies that must be considered before surgery include interforamenal anomalies, extraforamenal anomalies, and arterial anomalies. The intraforaminal anomalies involve midline migration, which places the VA at direct risk during corpectomy. Extraforaminal anomalies are related to VAs entering the transverse foramen at a level other than C6, which can increase the risk of injury during the anterior approach to the cervical spine. Arterial anomalies can be fenestrated, hypoplastic, or absent. These raise concern with the ability to maintain cerebral perfusion in the setting of damage to one of the VAs with the presence of contralateral arterial abnormality.

Two-year radiostereometric analysis evaluation of femoral head penetration in a challenging population of young total hip arthroplasty patients.

This prospective, randomized protocol evaluated femoral head penetration after total hip arthroplasty in a young population. Forty-five patients randomly received either a cross-linked or conventional ultrahigh-molecular-weight polyethylene (UHMWPE) liner in a noncemented hemispheric cup (Trilogy, Zimmer, Warsaw, Ind) with a 28-mm femoral head. Radiostereometric analysis film pairs, Harris hip, UCLA, SF-12, and Western Ontario and McMaster Universities scores were obtained through 2 years. Median femoral head penetration was less among cross-linked compared to conventional liners as follows: 0.06 mm (0.04-0.08 mm) vs 0.08 mm (0.02-0.19 mm) at 6 months, 0.07 mm (-0.14 to 0.16 mm) vs 0.11 mm (0.01-0.27 mm) at 1 year, and 0.065 mm (-0.04 to 0.193 mm) vs 0.169 mm (0.09-0.22 mm) at 2 years. Clinical outcomes were similar between the groups. Highly cross-linked UHMWPE demonstrated 55% less femoral head penetration compared to conventional polyethylene at 2 years. Despite improvements in the manufacturing process and sterilization of conventional UHMWPE, the femoral head penetration rate is unchanged from historical standards.

Is there a difference between simultaneous or staged decompressions for combined cervical and lumbar stenosis

Study Design We evaluated 43 patients diagnosed with tandem spinal stenosis (TSS) from 1999 to 2005 in an academic hospital. Objective The purpose of this study is to compare outcomes after simultaneous decompression of the cervical and lumbar spine versus staged operations. Summary of Background Data TSS is a rare degenerative disease affecting multiple spinal levels with limited research describing operative management. Methods Of our patients, 21 underwent simultaneous decompression of both the cervical and lumbar spine and 22 underwent staged decompression of the cervical spine followed by the lumbar spine at a later date. Medical records were reviewed for patient demographics, type and duration of symptoms, operative time, combined blood loss, cervical myelopathy modified Japan Orthopaedic Association Score, Oswestry Disability Index (ODI), major and minor complications, and average length of follow up. Each category was evaluated by Pearson correlations and unpaired Student t tests. Results With a mean follow-up of 7 years, both groups improved in JOA and ODI without a significant difference between the 2 operative groups in terms of major or minor complications, JOA, or ODI. Independent of the surgical algorithm, age above 68 years, estimated blood loss ≥400 mL, and operative time ≥150 minutes significantly increased the number of complications. Conclusions These results indicate that TSS can be effectively managed by either surgical intervention, simultaneous, or staged decompressions. However, patient age, blood loss, and operative time do significantly impact outcomes. Therefore, operative management should be tailored to the patients age and the option which will limit blood loss and operative time, whether that is by simultaneous or staged procedures.

Radiostereometric Analysis Study of Tantalum Compared with Titanium Acetabular Cups and Highly Cross-Linked Compared with Conventional Liners in Young Patients Undergoing Total Hip Replacement

BACKGROUND Radiostereometric analysis provides highly precise measurements of component micromotion relative to the bone that is otherwise undetectable by routine radiographs. This study compared, at a minimum of five years following surgery, the micromotion of tantalum and titanium acetabular cups and femoral head penetration in highly cross-linked polyethylene liners and conventional (ultra-high molecular weight polyethylene) liners in active patients who had undergone total hip replacement. METHODS This institutional review board-approved prospective, randomized, blinded study involved forty-six patients. Patients were randomized into one of four cohorts according to both acetabular cup and polyethylene liner. Patients received either a cementless cup with a titanium mesh surface or a tantalum trabecular surface and either a highly cross-linked polyethylene liner or an ultra-high molecular weight polyethylene liner. Radiostereometric analysis examinations and Short Form-36 Physical Component Summary, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), University of California Los Angeles (UCLA) activity, and Harris hip scores were obtained preoperatively, postoperatively, at six months, and annually thereafter. RESULTS All patients had significant improvement (p < 0.05) in Short Form-36 Physical Component Summary, WOMAC, UCLA activity, and Harris hip scores postoperatively. On radiostereometric analysis examination, highly cross-linked polyethylene liners showed significantly less median femoral head penetration at five years (p < 0.05). Steady-state wear rates from one year to five years were 0.04 mm per year for ultra-high molecular weight polyethylene liners and 0.004 mm per year for highly cross-linked polyethylene liners. At the five-year follow-up, the median migration (and standard error) was 0.05 ± 0.20 mm proximally for titanium cups and 0.21 ± 0.05 mm for tantalum cups. CONCLUSIONS In this young population who had undergone total hip replacement, radiostereometric analysis showed significantly less femoral head penetration in the highly cross-linked polyethylene liners compared with that in the conventional ultra-high molecular weight polyethylene liners. Penetration rates were one order of magnitude less in highly cross-linked polyethylene liners compared with ultra-high molecular weight polyethylene liners. There was no significant difference in proximal migration between the tantalum and titanium acetabular cups through the five-year follow-up (p > 0.19).

Identification of type 1: interforaminal vertebral artery anomalies in cervical spine MRIs.

Study Design. This is a prospective study. Objective. The aim of our study is to identify whether vertebral arteries (VA), normal or aberrant, are routinely described in cervical spine magnetic resonance imaging (MRI) interpretations. Summary of Background Data. VA injury is a serious complication of anterior cervical spine surgery. Aberrant VA anatomy is a potential cause of such complications. Therefore, VA anatomy should be evaluated in cervical MRIs. Methods. Six neuroradiologists were blinded to the study design and were asked to interpret 79 cervical MRIs. Of these, 39 had aberrant VAs, whereas 40 had normal VAs. Initially, the indications for the study included only a description of patients symptoms. The radiologists were then given the same MRIs with different indications. This time, the indications included the patients symptoms, a request for annotations on the VA, and a definition of VA anomaly. All of the MRI interpretations were then evaluated for the frequency and accuracy of VA description. Results. When the indications for the study did not specifically request a comment on VAs, the VA was never described (0%). When the indications included the specific request and definition, all 6 commented on the VA (100%). Three of the 6 radiologists were 100% accurate in identifying all 40 normal and 39 aberrant VAs, whereas the other 3 identified all 40 normal and 38 of 39 aberrant VAs. Conclusion. This study demonstrates that the VA is not a standard component of cervical spine MRI interpretations. Because of the significant complications related to its injury, VA anatomy, whether normal or variant, needs to be evaluated in cervical MRIs. When ordering a cervical MRI, surgeons should request a description of the VA and any anomalies.

Effects of magnetic resonance imaging signal change in myelopathic patients: a meta-analysis.

Study Design. Meta-analysis. Objective. Meta-analysis of the data to determine the effect of magnetic resonance imaging (MRI) signal change on preoperative and postoperative Japanese Orthopedic Association (JOA) scores and on recovery rate after surgery. Summary of Background Data. MRI signal changes are commonly found in myelopathy. There is often an increased T2 signal with or without a decreased T1 signal. The clinical significance of these signal changes remains debated. Methods. A comprehensive review of the literature was performed to identify all published studies with data on the presence of MRI signal change and JOA scores in myelopathic patients. T tests were performed to determine if there were significant differences between preoperative and postoperative JOA scores in patients with or without MRI signal change. The recovery rate was calculated for all patients undergoing surgery. T tests were performed to determine whether significant differences occurred in recovery rate in patients with or without MRI signal change. Results. A total of 16 studies were used for the meta-analysis. The total population included 886 patients: 659 with MRI signal change, and 227 without MRI signal change. Preoperative and postoperative JOA scores and the recovery rates were significantly better in patients without MRI signal changes (P < 0.05). The mean preoperative JOA scores were 10.63 and 11.37 for patients with and without MRI signal changes, respectively. The mean postoperative JOA scores were 13.37 and 14.19 for patients with and without MRI signal changes, respectively. The mean recovery rates were 43.87% and 49.31% for patients with and without MRI signal changes, respectively. Conclusion. A meta-analysis of the literature revealed statistically better preoperative and postoperative JOA scores and recovery rates following surgery in myelopathic patients without MRI signal change. Although the data were statistically significant, the clinical significance of the differences might be less due to the relatively small differences in actual values.

The Characteristics of Patients with Type 1: Intraforaminal Vertebral Artery Anomalies?

In a previous study, intraforaminal anomalies were found to occur at a rate of 7.6%. This increases the risk of injury to this vessel if the surgeon is unaware of such abnormalities preoperatively. The aim of our retrospective study was to identify patient factors that may predict anomalous intraforaminal vertebral arteries. Patient records were obtained from a previous study. In that study, the records of each consecutive patient who underwent cervical spine magnetic resonance imaging (MRI) for axial neck pain, radiculopathy, or myelopathy between January 2007 and January 2008 were reviewed. The social and medical histories of each patient were evaluated with respect to the presence or absence of an aberrant vertebral artery. We reviewed the medical records of the 250 patients whose MRIs were reviewed in the previous study. Seven patients were excluded for incomplete records. Chi-square and Fishers exact tests were performed to compare the normal vertebral artery anatomy patients to the aberrant patients. The medical records of 19 patients with aberrant vertebral arteries and 224 patients with normal vertebral arteries were reviewed. The aberrant group was significantly older than the normal group (P=.00015). The only diagnostic condition that represented a statistically significant difference between the 2 groups was incidence of cancer. A relationship may exist between patient age, cancer, and medialization of the vertebral artery. The mechanism of this possible relationship is unclear. Although aberrant vertebral arteries are rare, a surgeon should have raised suspicion of this possibility in patients with a history of cancer.

A lateral meniscus tear incarcerated behind the popliteus tendon: A case report☆

A 51-year-old male, sustained an injury to his left knee after being pinned between his motorcycle and a road barrier. In the ER, the patient complained of medial knee pain, and had a significant joint effusion. MRI demonstrated an ACL injury, medial meniscal tear, bone bruising and impaction at the lateral femoral condyle and tibial plateau, and a tear of the posterior horn of the lateral meniscus that was displaced behind the popliteus. Unfortunately, the patient also presented with a deep vein thrombosis and thus could not proceed to the operating room for two months. During this time, scar tissue developed around the lateral meniscus. The purpose of this report is to present an unusual variant of a common injury pattern previously unreported where the posterior horn of the lateral meniscus became incarcerated behind the popliteus tendon and was left in place. It is likely that our patient will develop osteoarthritis in the future, but considering the circumstances he received a favorable early clinical outcome. Early recognition and a mobile fragment are essential restoring a patients original anatomical features and achieving an optimal clinical outcome.

A modified technique for dowel fibular strut graft placement and circumferential fusion in the setting of L5-S1 spondylolisthesis and multilevel degenerative disc disease

BACKGROUND Traditional techniques for the treatment of isthmic spondylolisthesis pass a fibular dowel graft across the L5-S1 disc by using the anterior portion of the L5 body. OBJECTIVE To introduce a technique for the treatment of isthmic spondylolisthesis in the setting of multilevel degenerative disc disease in adults. Our modified technique allows us to traverse the L5-S1 disc via the L4-5 disc space thereby treating the degenerated disc at L4-5 simultaneously. METHODS A standard anterior discectomy was performed on L4-5. Using biplanar fluoroscopy, a Kirschner wire was placed beginning at the anterior third of the L5 superior endplate and ending at S1. An anterior cruciate ligament reamer was used to make a channel for the fibular allograft. Then, a femoral ring allograft was placed in the disc space at L4-5, and standard anterior lumbar interbody fusions were performed at any additional cephalad level(s). Afterward, posterior instrumented fusion was performed to complement the anterior fusion procedure (except at L5), and wide decompression followed. RESULTS All patients presented with isthmic spondylolisthesis and all had multilevel fusions. The mean slip angle was 32.6 degrees (37.8 degrees preoperatively), and mean lumbar index was 67%. After the procedure, the average endplate-to-dowel angle was 107.1 degrees compared with 134 degrees. All patients had clinical and radiographic evidence of solid fusion without the need for revisions. CONCLUSION The proposed advantage of our modified technique is twofold. The graft is placed nearly perpendicular to the L5-S1 interface, as it will behave more efficiently with respect to interfragmental compression. Also, surgeons gain access to fuse L4-5 anteriorly and posteriorly.