Francis H. Shen

Kummell’s disease: delayed post-traumatic osteonecrosis of the vertebral body

Delayed post-traumatic osteonecrosis, also known by its eponym Kummell’s disease, is a rarely reported clinical entity that likely occurs with higher frequency than recognized. We highlight a case of a 75-year-old female household ambulator who presented with significant thoracolumbar pain and delayed T12 collapse after a ground-level fall. The patient had sustained a trivial fall at home 4xa0months prior to this presentation and had been hospitalized in our institution at that time for a general medical workup. Dedicated spine radiographs were not obtained during this visit. However, lateral chest radiograph demonstrated an intact T12 vertebral body. The patient was able to mobilize successfully with therapy and was discharged home. During the interim between the initial fall and subsequent presentation, she resumed physical activity including ambulating independently and performing various housework. Approximately 4xa0months following her initial injury, the patient returned to a local emergency department with vague complaints of abdominal pain without any history of recent fall or injury. After an unremarkable workup, the patient was sent home. Ten days later, she represented to our institution’s emergency room with worsening pain. Radiographs and CT scan demonstrated interval collapse of the T12 vertebral body. A linear vacuum cleft was noted on X-rays and CT. An extensive workup to exclude other processes such as malignancy or infection, which was negative, ensued. Delayed post-traumatic vertebral collapse was diagnosed. A trial of medical management and therapy was attempted, but she continued to experience significant pain. A T12 vertebroplasty was therefore offered and performed to stabilize the injury and to relieve the pain. She was subsequently able to be discharged from the hospital and transitioned back to home life. At approximately 2xa0years following her injury, the patient was noted to be able to ambulate with a walking aid. Her final radiograph after her surgery demonstrated that the T12 vertebroplasty had maintained its height and sagittal alignment. This Grand Round case highlights the clinical presentation of Kummell’s disease. Aspects of the clinical entity that will be discussed include a historical review of the disease, hallmark radiographic findings and treatment options.

Intervertebral disk-like biphasic scaffold—demineralized bone matrix cylinder and poly(polycaprolactone triol malate)—for interbody spine fusion

Interbody fusion is an established procedure to preserve disk height and anterior fusion, but fusion with autografts, allografts, and metallic cages has its endogenous shortcomings. The objective of this study is to investigate whether a biphasic scaffold model, the native demineralized bone matrix cylinder in conjunction with degradable biomaterial poly(polycaprolactone triol malate), can be employed as a biological graft for interbody fusion. The poly(polycaprolactone triol malate) was synthesized by polycondensing malic acid and polycaprolactone and then the concentric sheet of poly(polycaprolactone triol malate) was fabricated into the demineralized bone matrix cylinder derived from rabbit femurs. Rabbit chondrocytes were loaded onto the three-dimensional constructs with 1-day in vitro culture and implanted into the subcutaneous dorsal pocket of nude mice. The chondrocytes/scaffold constructs are approximately two folds bigger than the scaffold-alone constructs after 12 weeks of implantation. X-ray and micro-computed tomography imaging showed endochondral bone formation in the chondrocytes/scaffold constructs as early as 4 weeks and showed that the bone intensity increased over time. Histological staining confirmed the above observation. By week 8, lamellar bone tissues were formed inside the demineralized bone matrix cylinder. In addition, the compression biomechanical test showed that the chondrocytes/scaffold constructs produced a significant higher compressive strength compared to the scaffold group. These results demonstrated that the inner-phase poly(polycaprolactone triol malate) degraded over time and was replaced by new bone in an in vivo environment.

Preoperative epidural injections are associated with increased risk of infection after single-level lumbar decompression.

BACKGROUND CONTEXTnLumbar epidural steroid injections (LESIs) are often performed as a treatment option for lumbar stenosis and radiculopathy before lumbar decompression surgery. Several case series have reported spinal infections after LESIs. There is lack of literature on the rate of postoperative infections after lumbar decompression in patients who had prior LESIs.nnnPURPOSEnThe goal of the present study is to employ a large national database to determine if there is an association between preoperative LESIs at various time intervals before lumbar decompression and the incidence of postoperative infection.nnnSTUDY DESIGN/SETTINGnRetrospective case control database study, Level III was used in this study.nnnPATIENT SAMPLEnThis study comprised Medicare patients over age 65 years who had a LESI within 1 year of single-level lumbar decompression surgery.nnnOUTCOME MEASURESnInternational Classification of Diseases, 9th Revision diagnosis codes for postoperative infection and Current Procedural Terminology procedure codes for treatment of postoperative infection were the outcome measures for this study.nnnMETHODSnThe PearlDiver Patient Records Database, an insurance-based database of patient records, was used for this study. The database was queried for LESI and single-level lumbar decompression procedures using Current Procedural Terminology codes. These study patients were then divided into four separate cohorts: (1) lumbar decompression within 1 month following LESI, (2) lumbar decompression between 1 and 3 months following LESI, (3) lumbar decompression between 3 and 6 months following LESI, and (4) lumbar decompression between 6 and 12 months following LESI. Unique control groups for each study cohort were created with patients who underwent single-level lumbar decompression without previous LESI and matched for major risk factors for infection, including age, gender, smoking status, diabetes, and obesity.nnnRESULTSnOverall, the rate of postoperative infection after single-level lumbar decompression after LESI remained relatively low, ranging between 0.8% and 1.7%. The incidence of 90-day postoperative infection after lumbar decompression was significantly higher than matched controls in groups with LESI within 1 month (OR=3.2, p<.0001) and 1-3 months before surgery (OR=1.8, p<.0001). The incidence of 90-day postoperative infection was not significantly different from matched controls in groups with LESI between 3-6 months (OR=1.3, p=.15) and 6-12 months before decompression surgery (OR=1.3, p=.18) CONCLUSIONS: Single-level lumbar decompression within 3 months after LESI may be associated with an increased rate of postoperative infection. Increasing the time interval between LESI and single-level lumbar decompression surgery to at least 3 months may decrease postoperative infection rates.

Primary cervical amyloidoma: a case report and review of the literature

BACKGROUND CONTEXTnPrimary solitary amyloidosis or amyloidoma is a disease process characterized by the focal deposition of amyloid in the absence of a plasma cell dyscrasia with normal serum protein measurements. Solitary amyloidomas affecting the vertebrae are very uncommon but typically affect the thoracic spine. Primary cervical amyloidosis is an exceedingly rare entity with exceptionally good prognosis, but requires diligence of the treating physician to establish the diagnosis and implement the appropriate surgical intervention.nnnPURPOSEnThis study aimed to present a rare case of primary cervical amyloidosis with long-term follow-up and review the clinical presentation, characteristic imaging findings, diagnostic pathology, differential diagnosis, treatment algorithm, and prognosis of the disease entity. This case demonstrates the progressive resorption of the amyloidoma over time after surgical stabilization. Previous reported cases of primary cervical amyloidosis will also be reviewed.nnnSTUDY DESIGNnThis study is a report and review of the literature.nnnMETHODSnA 77-year-old woman presented with a several-week history of gradual progressive weakness in her upper and lower extremities. Computed tomography and magnetic resonance imaging demonstrated a retro-odontoid nonenhancing soft-tissue mass, with erosive bony changes and severe mass effect on the upper cervical cord. The patient was taken to the operating room for decompression and posterior spinal stabilization.nnnRESULTSnIntraoperative tissue specimens demonstrated amyloidosis and extensive systemic workup did not reveal any inflammatory processes, systemic amyloidosis, or plasma cell dyscrasia. Postoperatively, the patient regained full strength and ambulatory status. The patient remains asymptomatic at a 2-year follow-up. A postoperative follow-up magnetic resonance imaging demonstrated complete resorption of the residual amyloidoma.nnnCONCLUSIONSnPrimary solitary amyloidosis is a rare form of amyloidosis that is important to differentiate given its excellent prognosis with surgical management. Treatment should include surgical decompression and spinal stabilization. This is the first case report to clinically and radiographically demonstrate the progressive resorption of a primary amyloidoma over time after surgical stabilization in the upper cervical spine. It is imperative that surgeons encountering such lesions maintain a high suspicion for this rare disease entity and advise their pathologists accordingly to establish the correct diagnosis.

Candida lusitaniae discitis after discogram in an immunocompetent patient

BACKGROUND CONTEXTnDiscitis or epidural abscess after discogram is a rare but known complication. It is more commonly bacterial; however, fungal discitis has been previously reported in immunocompromised patients. The management of fungal discitis in immunocompetent patients is rarely presented or addressed in the literature.nnnPURPOSEnTo present a rare atypical fungal discitis after routine discogram with a typical presentation in an immunocompetent host, review diagnostic and management guidelines for discitis, and provide recommendations for management of atypical discitis in immunocompetent patients.nnnSTUDY DESIGNnCase report and review of the literature.nnnMETHODSnA 40-year-old woman presented with a 3-week history of progressively worsening low back pain after a lumbar discogram. Magnetic resonance imaging revealed L3-L4 discitis without an epidural abscess. Left L3 and L4 hemilaminectomies with L3-L4 discectomy were performed. An inflammatory mass was seen in the L3-L4 disc space region extending to the left L3 foramen.nnnRESULTSnCulture specimens obtained during surgery from both the disc and epidural space speciated to Candida lusitaniae. The patient completed a 6-month course of fluconazole therapy. At 2-year follow-up, she continued to be asymptomatic, without any recurrence of infection or neurologic sequelae.nnnCONCLUSIONSnWe report a case of C. lusitaniae spondylodiscitis after discography in an immunocompetent patient with long-term follow-up. Clinicians must maintain a high index of suspicion for discitis in patients who undergo this procedure. If discitis is suspected, culture specimens must be evaluated for fungal and mycobacterial organisms, even in the immunocompetent host. With proper surveillance, surgical intervention, and appropriate postoperative follow-up, this complication can be effectively managed with excellent long-term outcome.

Intervertebral Disc Degeneration and Ectopic Bone Formation in Apolipoprotein E Knockout Mice

Cardiovascular risk factors are known to be associated with intervertebral disc degeneration, but the underlying mechanism is still unclear. The ApoE knockout (KO) mouse is a well‐established model for atheroscelorosis. We hypothesized that ApoE is involved in maintaining disc health and that ApoE KO mice will develop early disc degeneration. Discs of ApoE KO and wild‐type (WT) mice were characterized with histological/immunological, biochemical, and real‐time RT‐PCR assays. A comparison of the extracellular matrix production was also performed in disc cells. We demonstrated that ApoE was highly expressed in the endplates of WT discs, and ectopic bone formed in the endplates of ApoE KO discs. Glycosaminoglycan content was decreased in both ApoE KO annulus fibrosus (AF) and nucleus pulposus (NP) cells. Collagen levels were increased in AF and decreased in NP cells. Matrix metalloproteinase‐3, ‐9, and ‐13 expressions were increased, which may partially explain the impaired matrix production. We also found collagen I, II, aggrecan, and biglycan mRNA expressions were increased in AF cells but decreased in NP cells. Apoptosis was increased in the ApoE KO NP tissue. These results suggest early disc degeneration changes in the ApoE KO mice. ApoE may play a critical role in disc integrity and function.