Cervical instability presenting as thoracic pain: case report and literature review.

STUDY DESIGN: Case report. OBJECTIVE: To report a case of cervical instability from an os odontoideum that presented as posterior thoracic pain and to present a review of the literature. BACKGROUND: Thoracic posterior paraspinal spasms and pain are common chief complaints in individuals with spinal abnormalities. METHODS: A 19-year-old man presented with posterior thoracic pain for nearly 1 year following a college sports-related injury (lacrosse). Computed tomography and magnetic resonance imaging did not reveal any significant thoracic or lumbar spinal cord or nerve root pathology, but did reveal an incidental finding of an os odontoideum. RESULTS: Surgical stabilization of the atlantoaxial instability resulting from the os odontoideum resulted in complete resolution of the patient's thoracic pain. CONCLUSIONS: Thoracic back pain without a clear thoracic spine etiology warrants further workup to rule out the possibility of spinal instability.

Case report: Bowel perforation presenting as subcutaneous emphysema of the thigh.

Necrotizing fasciitis is recognized as a surgical emergency. Early detection and aggressive surgical débridement are crucial to reduce patient mortality and morbidity. There are, however, other causes of subcutaneous emphysema. We present the case of a 64 year-old patient with a history of postsurgical radiation for rectal carcinoma with subcutaneous emphysema of the thigh in the presence of urinary sepsis. Surgical exploration revealed the source of the emphysema to be an enterocutaneous fistula. The patient had an unstable and prolonged hospitalization after débridements of the thigh and abdominal surgery and was readmitted for recurrence of thigh drainage, but eventually was discharged; nine months after the initial diagnosis all wounds had healed and he was walking with a walker. Despite an otherwise benign clinical appearance, the radiographic finding of subcutaneous emphysema in the absence of penetrating trauma must be considered a case of a necrotizing soft tissue infection until proven otherwise.

Acetabular retroversion in military recruits with femoral neck stress fractures.

UNLABELLED: Acetabular retroversion (AR) alters load distribution across the hip and is more prevalent in pathologic conditions involving the hip. We hypothesized the abnormal orientation and mechanical changes may predispose certain individuals to stress injuries of the femoral neck. We retrospectively reviewed the anteroposterior (AP) pelvic radiographs of 54 patients (108 hips) treated for a femoral neck stress fracture (FNSF) and compared these radiographs with those for a control group of patients with normal pelvic radiographs. We determined presence of a crossover sign (COS), femoral neck abnormalities, and neck shaft angle. The prevalence of a positive COS was greater in patients with stress fractures than in the control subjects (31 of 54 [57%] versus 17 of 54 [31%], respectively) and higher than for control subjects reported in the literature. Thirteen patients had radiographic changes of the femoral neck consistent with femoroacetabular impingement (FAI). These radiographic abnormalities were seen more commonly in retroverted hips. A greater incidence of AR was noted in patients with FNSF. Potential implications include more aggressive screening of military recruits with AR and the new onset of hip pain. Finally, we present an algorithm we use to diagnose and treat these relatively rare FNSFs. LEVEL OF EVIDENCE: Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Percutaneous Pedicle Screws in the Obese: Should the Skin Incision Be More Lateral?

OBJECTIVE: To determine if the skin incision for lumbar percutaneous pedicle screws should be more lateral in the obese patient. METHODS: This was a retrospective radiographic analysis of 30 obese and non-obese lumbar spine computed tomography (CT) radiographs comparing the depth of soft tissue along the anatomic axis of the pedicle at L4 and L5. RESULTS: The average distance from the pedicle trajectory on the skin to the lateral border of the pedicle at L4 was 1.4 cm and 3.8 cm in the non-obese and obese groups, respectively. The average distance from the pedicle trajectory on the skin to the lateral border of the pedicle at L5 was 2.1 cm and 4.3 cm in the non-obese and obese groups, respectively; both these differences reached statistical significance, p <0.05. CONCLUSIONS: This radiographic study supports a more lateral start point for percutaneous pedicle screws in obese patients to maintain an anatomic trajectory when inserting percutaneous pedicle screws into the lumbar spine at L4 and L5. If a skin incision is made at only 1 cm lateral to the pedicle in the obese patient, the surgeon often has to place significant traction on the skin edge to lateralize their instrumentation to achieve an appropriate angle of insertion. By making a more lateral skin incision, less manipulation of the skin and soft tissues is needed to maintain an anatomic trajectory of the pedicle screw. Decreasing soft tissue manipulation may decrease wound and instrumentation complications in this at-risk population.

Chondromyxoid fibroma of the lumbar spine in a pediatric patient.

Chondromyxoid fibroma is a rare nonmalignancy that comprises <1% of all bone tumors. It typically presents with pain, swelling, and tenderness to palpation. The lesion has a predilection for the metaphysis of long bones of the lower extremity, most commonly in the proximal tibial metaphysis. Patients often present in their second or third decade of life, although some reports have included a younger average age. Sporadic reports of chondromyxoid fibroma in the spine are found in the literature. This article presents the second case of a chondromyxoid fibroma of the lumbar spine in a pediatric patient, along with a literature review with emphasis on recurrence rates and malignant transformation.

Thoracic Fracture through a Prior Instrumented Arthrodesis in a Patient with Ankylosing Spondylitis without Hardware Loosening: A Case Report.

The objective of this article is to report a case of a patient with ankylosing spondylitis who sustained a fracture through a prior solid arthrodesis without loosening or changing posterior instrumentation. There have been few cases reported of a patient with ankylosing spondylitis suffering a fracture through a prior instrumented arthrodesis. None have noted the instrumentation remaining intact with the fracture through the middle of the construct. The surgeon must be aware of this possibility to avoid spinal instability that may lead to a neurological deficit. We retrospectively reviewed the case. A review of the literature was performed through a PubMed search. A patient was found to have a fracture within a prior construct despite the presence of a posterior instrumentation. The mechanism of failure was a three-column spine fracture with "bending" of the rods. This patient was treated with a revision posterior/anterior instrumentation and fusion with placement of larger-diameter rods for added stiffness. Fractures through a prior instrumented arthrodesis are rare but still can occur in the ankylosing spondylitis patient. Given the higher risk of epidural hematoma and neurological compromise in this patient population, the surgeon must keep this on the differential diagnosis when treating patients with a prior instrumented arthrodesis.

The compromise between motion preservation and arthrodesis.

COMMENTARY ON: Cunningham BW, Dawson JM, Hu N, et al. Preclinical evaluation of the Dynesys posterior spinal stabilization system: a nonhuman primate model. Spine J 2010;10:775-83 (in this issue).

Plantar flexion influences radiographic measurements of the ankle mortise.

BACKGROUND: The treatment of ankle fractures often depends on the integrity of the deltoid ligament. Diagnosis of a deltoid ligament tear depends on the measurement of the medial clear space. We sought to evaluate the impact of ankle plantar flexion on the medial clear space. METHODS: Mortise radiographs were made for twenty-five healthy volunteers, with the ankle in four positions of plantar flexion (0 degrees, 15 degrees, 30 degrees, and 45 degrees). Four observers measured the medial clear space and the superior clear space on each radiograph. The mean medial clear space at 0 degrees was defined as the control, and the deviation of the medial clear space from the control value was calculated at 15 degrees, 30 degrees, and 45 degrees of plantar flexion. The ratio of the medial clear space to the superior clear space was determined on all radiographs, and ratios that were false-positive for a deltoid ligament injury were identified. RESULTS: Fourteen male and eleven female volunteers were evaluated. The average increase in the medial clear space when ankle plantar flexion was increased from 0 degrees to 45 degrees was 0.38 mm (95% confidence interval, 0.18 to 0.58 mm). This increase was significant (p = 0.005). The average increase in the medial clear space was 0.04 mm when ankle plantar flexion was increased from 0 degrees to 15 degrees and 0.22 mm when it was increased from 0 degrees to 30 degrees. Neither of these changes was significant (p = 0.99 and 0.20). The prevalence of false-positive findings of deltoid injury based on the ratio of the medial clear space to the superior clear space increased as ankle plantar flexion increased, but this increase did not reach significance in our study group (p = 0.18). CONCLUSIONS: Plantar flexion of the ankle produces changes in radiographic measurements of the medial clear space. The potential for false-positive findings of deltoid disruption increases with increasing ankle plantar flexion.

Thermal necrosis complicating reamed intramedullary nailing of a closed tibial diaphysis fracture: a case report.

A case report of thermal necrosis of the tibia after reamed intramedullary nailing is presented. Given the consequences of this complication, the proper use of reaming technique and equipment is emphasized.