Robert L. Wimberly

Prognostic Value of Psychological Testing in Patients Undergoing Spinal Cord Stimulation: A Prospective Study

OBJECTIVE : Associations between psychological and physical states are understood to exist, and the development of standardized psychological tests has allowed quantitative evaluation of this relationship. We tested whether associations exist between psychological test instruments and patients selected for therapeutic trials of spinal cord stimulation (SCS) for chronic, intractable pain. METHODS : Fifty-eight patients selected for SCS were tested prospectively with a battery of standardized psychological tests : Minnesota Multiphasic Personality Inventory with Wiggins content scales, Symptom Check List-90, and Derogatis Affects Balance Scale. Associations between treatment outcomes and preoperative test scores and clinical variables were tested by univariate and multivariate statistical analyses, in which the dependent variables were as follows : 1) the outcome of a therapeutic trial of stimulation (whether the patient derived sufficient reported pain relief with a temporary electrode to proceed with a permanent implant), and 2) long-term outcome of treatment with the permanent implant, as determined by disinterested third-party interview. RESULTS : Significant associations (P ≤ 0.01) were observed between the outcome of the therapeutic trial of stimulation and psychological test results ; patients with low anxiety scores on the Derogatis Affects Balance Scale and with high organic symptoms scores on the Wiggins test were significantly more likely to proceed to permanent implants, as determined by multivariate statistical models. There was an elevation in the Minnesota Multiphasic Personality Inventory hypochondriasis scale in these patients by univariate (P = 0.02), but not by multivariate, models. The multivariate model also identified young age, reproduction of leg pain by straight leg raising, and bilateral leg pain as favorable prognostic factors. The only association with favorable long-term outcome of implantation of a permanent device, by univariate analysis, was an elevated joy score on the Derogatis Affects Balance Scale. Multivariate analysis revealed no statistically significant predictors of long-term outcome. CONCLUSION : Because our study population was selected on the basis of recognized prognostic factors and long clinical experience, it may not be possible to generalize our findings to the overall pain clinic referral population. In the subpopulation we have chosen for SCS trials, psychological testing is of modest value and explains little of the observed variance in outcome. We find little evidence for selecting patients for SCS on the basis of psychological testing. Because self-reported outcome measures may themselves reflect the patients psychological state, these findings should be considered carefully, in overall clinical context. A prospective study with additional objective outcome measures is underway, which will address some of these issues.

Spine Trauma in Very Young Children: A Retrospective Study of 206 Patients Presenting to a Level 1 Pediatric Trauma Center

Background: The immature spine has anatomic and biomechanical properties that differ from the adult spine and result in unique characteristics of pediatric spinal trauma. Although distinct patterns of spinal injury have been identified in children younger than 10 years of age, little research has explored the differing characteristics of spinal trauma within this age group, particularly in the very young. The purpose of this study is to identify differences in the epidemiology and characteristics of spinal trauma between children under the age of 4 years and those between 4 and 9 years of age. Methods: A review of all patients treated for spinal injury at a single large level I pediatric trauma center between 2003 and 2011 was conducted. Demographic data, injury mechanism, neurologic status, and details of any associated injuries were compiled. Radiographic studies were used to determine injury location and fracture classification. The patient population was divided into 2 groups: the infantile/toddler (IT) group (ages 0 to 3 y) and the young (Y) group (ages 4 to 9 y). Data were compared between these groups using the &khgr;2 test and the Student t test to identify differences in injury characteristics. Results: A total of 206 patients were identified. Fifty-seven patients were between 0 and 3 years of age and 149 were between 4 and 9 years old. Although motor vehicle collision was the most common cause of injury in both the groups, nonaccidental trauma was responsible for 19% of spine trauma among patients aged 0 to 3 years. Cervical spine injuries were much more common in the youngest patients (P<0.05) with injuries primarily in the upper cervical spine. Children in the IT group were more likely to sustain ligamentous injuries, whereas Y patients had more compression fractures (P<0.05). Neurologic injury was common in both the groups with IT patients more often presenting with complete loss of function or hemiplegia and Y patients sustaining more spinal cord injuries (P<0.05). IT patients had a 25% mortality rate, which was significantly higher than that of the Y group (P=0.005). Conclusions: This study shows many significant differences in characteristics of spinal injury in infants/toddlers when compared with older children. These differences can help guide diagnostic evaluation and initial management, as well as future prevention efforts. Level of Evidence: Level III.

Characteristics of spinal injuries secondary to nonaccidental trauma

Background: Nonaccidental trauma (NAT) is considered an uncommon cause of spine trauma in the pediatric population. Little has been published on such injuries and no large series is available in the literature. The purpose of this study is to describe the incidence and characteristics of spine trauma secondary to NAT. Methods: An IRB-approved retrospective review of all patients presenting to a single level 1 pediatric trauma center with a spinal injury between 2003 and 2011 was performed. Patients were identified using our institution’s trauma registry. Medical records were reviewed to identify all spine injuries that occurred as a result of NAT. These cases were reviewed for details regarding injury mechanism, type and location of injury, associated injuries, and the treatment. Our institution’s NAT database was also queried to identify the total number of patients formally determined to have sustained any injury as a result of NAT during the same period. Results: NAT was the cause of 11/342 (3.2%) spine injuries diagnosed during the study period. A total of 726 cases of NAT were identified, with spine injury present in 1.5%. All patients with spine trauma secondary to NAT were under the age of 2 years with an average age of 7 months. Among patients below 2 years with spinal trauma, NAT was tied as the most common mechanism, resulting in 38% of injuries. Eight of the 11 patients’ spine injuries were cervical and 7 of these injuries were in the atlanto-occipital and atlantoaxial regions. Multilevel spine trauma was present in 64% of patients. Associated head and thoracic trauma was present in 73% and 36% of patients, respectively. Neurological injury was found in 54% of patients. The majority of injuries were treated nonoperatively and 1 patient required surgical management. Conclusions: NAT represents a very common yet often overlooked cause of spinal trauma in children under the age of 2 years. Because of its frequency in this age group, clinicians should consider including an assessment of the spine in all young NAT patients. Patients with spinal trauma sustained as a result of NAT must undergo a thorough evaluation for associated injuries remote to the spine, neurological deficit, and multilevel spine injury. Summary: NAT is a common mechanism of spinal injury in patients below 2 years of age.

Acute complications associated with removal of flexible intramedullary femoral rods placed for pediatric femoral shaft fractures.

Background: The American Academy of Orthopaedic Surgeons position statement on the treatment of pediatric femoral shaft fractures could not comment on the safety of flexible intramedullary (IM) rod removal because of a lack of published evidence. This study reviews the acute complications of flexible IM rod removal from pediatric patients treated for femoral shaft fractures. Methods: A retrospective clinical and radiographic analysis at a single institution over a 5-year period. Demographic and radiographic parameters were analyzed to determine their influence on intraoperative and immediate postoperative complications. Results: One hundred sixty-three subjects (133 males, 30 females), mean age of 9.3±2.8 years (range, 2.7 to 14.8 y) and mean weight of 34.4±15.3 kg (range, 14.0 to 139.0 kg), underwent femoral flexible IM rod removal a mean 12.4±10.8 months (range, 2.4 to 63.8 mo) after placement with mean operative time of 51.1±22.3 minutes (range, 10 to 131 min). One hundred fifty-one subjects (92.6%) had stainless-steel Ender rods and the remaining nails were titanium. There were no significant demographic, intraoperative, or radiographic differences comparing subjects with Ender versus titanium rods. Indications for rod removal were pain at insertion site, family request, or surgeon’s recommendation. There were 4 (2.5%) minor intraoperative difficulties, including the inability to remove 1 of 2 rods secondary to IM migration (n=1) and complete bone overgrowth at insertion site resulting in prolonged extraction time (n=3). Three of the 4 subjects had the rods placed >60 months before removal. Immediately postoperative (n=134), there were 4 (3.0%) complications, including superficial wound infection (n=3, 2.2%) and knee contracture (n=1, 0.8%). Subjects were released to full activities at a mean 4.7±1.8 weeks postoperatively with no known postoperative fractures. Conclusions: The rate of intraoperative and immediate postoperative complications is low. Neither patient demographics, fracture characteristics, nor operative technique influenced the complication rate. Intraoperative difficulties may be minimized with removal of rods before signs of overgrowth. Levels of Evidence: Level IV, intervention case series

Neurological and vascular injury associated with supracondylar humerus fractures and ipsilateral forearm fractures in children.

Background: Approximately 5% of supracondylar humerus fractures in children are associated with an ipsilateral forearm fracture, often referred to as a floating elbow when both injuries are displaced. Historically, these patients have higher complication rates than patients with an isolated supracondylar humerus fracture. The purpose of this study was to review the acute neurologic and vascular injuries in patients with ipsilateral, operative supracondylar humerus and forearm fractures and compare the findings with a cohort of isolated, operative supracondylar humerus fractures. Methods: We performed an IRB-approved, retrospective review of all pediatric patients with ipsilateral, operative supracondylar humerus and forearm fractures from a single institution and compared our findings to a cohort of isolated, operative supracondylar humerus fractures. Results: A total of 150 patients with operative supracondylar humerus and ipsilateral forearm fractures were compared with 1228 patients with isolated, operative supracondylar humerus fractures. Twenty-two of the 150 (14.7%) floating elbow patients had documented pretreatment nerve palsies compared with 96/1228 (7.8%) of isolated injury patients (P=0.006). Eighteen of 22 nerve palsies were in patients with forearm fractures that required reduction. The overall incidence of nerve palsy was 18.9% (18/95) when a forearm fracture required reduction compared with only 7.3% (4/55) in a forearm fracture that was not reduced (P=0.05). We did not find a significant difference in the rate of pulseless extremities when comparing the ipsilateral (6/150 4%) and isolated (50/1228 4.1%) injury patients. No compartment syndromes were identified in any patient with an ipsilateral injury. Conclusions: The rate of acute neurologic injury in ipsilateral supracondylar humerus and forearm fractures is almost twice than that found in patients with isolated supracondylar humerus fractures. This rate increases further when the forearm fracture requires a manipulative reduction. The likelihood of a pulseless extremity was not dependent upon the presence of a forearm injury in our study. The presence of an ipsilateral forearm fracture should alert the surgeon to carefully assess the preoperative neurovascular status of patients with supracondylar humerus injuries. Level of Evidence: Level III.

The use of ultrasound in the management of septic arthritis of the hip.

In the assessment of septic arthritis of the hip in a pediatric population, ultrasound is a safe and easily conducted method to confirm an effusion. The need for MRI to further evaluate the patient for adjacent infection before treatment is debatable. Once an effusion is confirmed on ultrasonography, we have found that septic arthritis of the hip does not need advanced imaging before arthrotomy and debridement. Patients who fail to clinically respond to an initial hip arthrotomy and appropriate antibiotics may benefit from an MRI for the identification of concomitant infections that may require surgical intervention.

The effects of restraint type on pattern of spine injury in children

Introduction: While the use of vehicular restraints has reduced the morbidity and mortality of children involved in motor vehicle collisions (MVC), to our knowledge, no study has examined the relationship between restraint type and patterns of pediatric spinal injuries. The purpose of this study is to evaluate this association and review the spinal injuries sustained in children involved in MVC. Methods: We completed an IRB-approved, retrospective chart review of all patients below 10 years of age presenting to a level 1 pediatric trauma hospital with spine injuries sustained in MVC from 2003 to 2011. We reviewed prehospital data, medical records, and radiographs to establish the restraint type and characterize the spinal injuries sustained. Results: A total of 97 patients were identified with spinal trauma secondary to MVC with appropriate and documentation of restraint type. Results are reported regardless of whether the restraint employed was properly used per established guidelines. Car seat/booster seat (C/B) patients sustained significantly higher rates of cervical spine (62%) and ligamentous (62%) injuries than the 2-point (2P) (10%) and 3-point (3P) restraint (24%) groups (P<0.001). Two-point and 3P restraint use was associated with significantly higher rates of thoracolumbar injuries (67% and 62%, respectively) than the C/B (14%) and unrestrained (0%) groups (P<0.001). Two-point and 3P passengers also had a higher rate of flexion-distraction injuries (P<0.001). Patients in the unrestrained group sustained a significantly higher rate of cervical spine (80%) and ligamentous (40%) injuries than the 2P and 3P groups (P<0.001). No differences were found in the type or location of injury between the 2P and 3P groups. Significant differences in proper restraint use were identified between age groups with younger children demonstrating higher rates of proper restraint use (P<0.01). Conclusions: Two-point or 3P seatbelt use is associated with lower rates of cervical spine trauma but higher rates of thoracic and lumbar trauma, particularly flexion-distraction injuries, when compared with car or booster seats. Children in C/B and those who are unrestrained sustain high rates of cervical spine injury. Level of Evidence: Level III—prognostic study.

Osteomyelitis is Commonly Associated With Septic Arthritis of the Shoulder in Children.

Purpose: To describe the clinical presentation, management, and outcomes of surgically treated septic arthritis of the shoulder in a pediatric population. Methods: A retrospective chart review over 5 years of children with operatively managed septic arthritis of the shoulder was completed. Demographics, clinical presentation, symptoms duration, antibiotic regimen and duration, number of surgical procedures, and evaluation of laboratory value improvements were collected. Pretreatment and final radiographs were assessed. Causative organisms were reviewed. Patients were stratified in age groups to determine clinical variability based upon patient age. Results: A total of 22 children, ages 15 days to 14 years (average 37.3 mo), were treated for septic arthritis of the shoulder from 2006 to 2010 at a single pediatric institution. All patients were managed with open anterior arthrotomy at an average of 1.95 days after initial orthopaedic consultation (range, 0 to 15 d). Multiple presenting signs were noted; the most common was decreased use (59%). Average admission laboratory values include C-reactive protein 10.6 (range, 0.3 to 41.6), erythrocyte sedimentation rate 62.8 (range, 11 to 107), and white blood cell count 14.9 (range, 5.9 to 31.7). Initial radiographs were read as normal in 12 patients, concern for osteomyelitis in 5, cortical irregularity in 4, effusion in 3, and neoplasm in a single child. Nineteen patients had a preoperative magnetic resonance imaging and 15 demonstrated an effusion, 15 had evidence of humeral osteomyelitis, 5 had a subperisoteal abscess, and 4 had soft tissue abscesses. Eight patients remained culture negative. The most commonly identified organism was methcillin-resistant Staphylococcus aureus (MRSA) (22.7%). The patients under 12 months of age revealed more diverse organisms at culture and were less likely to have MRSA. All patients averaged 1.55 (range, 1 to 5) surgical procedures and had an average hospital stay of 13.5 days. Intravenous antibiotics averaged 16.3 days followed by an average of 34 days of oral treatment. MRSA patients were significantly more likely to require multiple operations to eradicate the infection (P<0.02) and had a longer duration of intravenous antibiotic use (P<0.003). MRSA patients were more likely to have abnormal radiographs at final follow-up (P<0.03). Conclusions: Septic arthritis of the shoulder in children is commonly associated with adjacent osteomyelitis. Pediatric septic arthritis of the shoulder due to MRSA bacteria can have a more virulent course than other bacterial causes, but is a less commonly identified organism in the youngest patients. Significance: To our knowledge, this is one of the largest series published concerning the treatment, course, and outcomes of pediatric septic arthritis of the shoulder. Level of Evidence: Level III—therapeutic.

Biomechanical Analysis of Retrograde Flexible Intramedullary Nail Constructs in a Simulated Pediatric Femur Fracture Model

Background: Various flexible intramedullary nail (FIMN) constructs for pediatric femur fractures are described; however, no biomechanical study has compared stability of medial-lateral entry versus all-lateral entry retrograde nailing. Our purpose is to compare the rotational and bending stiffness of 2 different FIMN constructs and 2 different materials in a simulated pediatric femur fracture model. Methods: Eighty adolescent-sized composite femurs were used to simulate transverse (40 femurs) and oblique (40 femurs) mid-diaphyseal fractures. Retrograde FIMN of the femurs was performed using either 3.5 mm titanium (Ti) or 3.5 mm stainless-steel (SS) flexible nails in 2 configurations: 2 “C”-shaped nails (CC) placed through medial and lateral entry sites or 1 “C”-shaped nail and 1 “S”-shaped nail (CS) placed through a single lateral entry site. Models were first tested in 10 cycles of axial rotation to ±1 N m of torque at a rate of 0.5 degrees/s under 36 kg of compression. Axial compression was performed and bending stiffness defined as the force required to achieve 10 degrees varus at the fracture site. Results: No differences were noted in rotational stiffness comparing Ti and SS nails regardless of nail configuration or fracture pattern. Comparable rotational stability was found for CC and CS configurations with SS implants for both fracture patterns. The CS construct (0.60 N m/degree) was stiffer in rotation than the CC construct (0.41 N m/degree) with Ti implants in the transverse fracture model (P<0.005). SS nails provided greater bending stiffness than Ti nails in both oblique and transverse fracture patterns, regardless of nail construct. The all-lateral entry (CS) construct demonstrated statistically significant greater bending stiffness regardless of implant material or fracture pattern (P<0.03). Conclusions: An all-lateral entry (CS) FIMN construct demonstrated greater bending stiffness in both fracture patterns and materials. Ti and SS implants have comparable rotational stiffness in all fracture patterns and materials; however, SS nails were superior at resisting bending forces in both fracture patterns. CS nail configuration and SS implants demonstrated superior bending stiffness and rotational stiffness when compared with the more commonly used CC construct and Ti implants. Level of Evidence: NA (biomechanical study).

Segmental metadiaphyseal humeral bone loss in pediatric trauma patients: a case series.

Background: The management of posttraumatic bone loss is complicated and often requires complex reconstructive procedures. No options exist that are specific to the treatment of the growing skeleton that has intercalary bone loss. We have observed reconstitution of the humerus in 2 cases that have precluded extensive management. Methods: Two pediatric patients sustained traumatic injuries to the upper extremities, including humeral bone loss, and are presented after spontaneous reconstitution of the segmental bone loss. Results: With treatment restricted to soft-tissue injury and bone stabilization with external fixation, both patients demonstrated radiographic healing of humeral segmental bone loss. Both patients were thought to have a partially intact periosteal sleeve. They have returned to sporting activities with mild loss of function. Conclusions: In certain pediatric injuries, spontaneous healing of segmental bone defects can occur. This response may obviate the need for complex, interventional procedures. Levels of Evidence: Level IV—case series.