Nicholas Theodore, Paul M. Arnold and Ankit I. Mehta
Robert F. Heary, Paul A. Anderson and Paul M. Arnold
Kavelin Rumalla, Kyle A. Smith and Paul M. Arnold
Immunoglobulin G4–related disease (IgG4-RD) is a recently defined condition characterized by inflammatory tumefactive lesions in various organ systems. IgG4-RD is a clinical and radiological diagnosis of exclusion and requires the presence of specific histopathological criteria for diagnosis.
A 50-year-old man presented to an outside hospital with a 3-month history of progressively worsening back pain and symptoms of pleurisy, nasal crusting, and hematochezia. Radiological workup revealed an epidural-paraspinal mass with displacement of the spinal cord, destruction of the T5–6 vertebrae, and extension into the right lung. Biopsy sampling and subsequent histopathological analysis revealed dense lymphoplasmacytic infiltrate with an increased number of IgG4-positive plasma cells and a storiform pattern of fibrosis. With strong histopathological evidence of IgG4-RD, the patient was started on a regimen of prednisone. Further testing ruled out malignant neoplasm, infectious etiologies, and other autoimmune diseases. Two weeks later, the patient presented with acute-onset paraplegia due to spinal cord compression. The patient underwent decompression laminectomy of T5–6, posterior instrumented fusion of T2–8, and debulking of the epidural-paraspinal mass. After the continued administration of glucocorticosteroids, the patient improved remarkably to near-normal strength in the lower extremities and sensory function 6 months after surgery.
To the authors' knowledge, this is the first case of IgG4-related epidural inflammatory pseudotumor and spinal cord compression in the United States. This case highlights the importance of early administration of glucocorticosteroids, which were essential to preventing further progression and preventing relapse. IgG4-RD evaluation is important after other diseases in the differential diagnosis are ruled out.
Paul M. Arnold, Karen K. Anderson, Abdulhafez Selim, Randall F. Dryer and J. Kenneth Burkus
Heterotopic ossification (HO) has been reported following total hip, knee, cervical, and lumbar arthroplasty, as well as following posterolateral lumbar fusion using recombinant human bone morphogenetic protein–2 (rhBMP-2). Data regarding HO following anterior cervical discectomy and fusion (ACDF) with rhBMP-2 are sparse. A subanalysis was done of the prospective, multicenter, investigational device exemption trial that compared rhBMP-2 on an absorbable collagen sponge (ACS) versus allograft in ACDF for patients with symptomatic single-level cervical degenerative disc disease.
To assess differences in types of HO observed in the treatment groups and effects of HO on functional and efficacy outcomes, clinical outcomes from previous disc replacement studies were compared between patients who received rhBMP-2/ACS versus allograft. Rate, location, grade, and size of ossifications were assessed preoperatively and at 24 months, and correlated with clinical outcomes.
Heterotopic ossification was primarily anterior in both groups. Preoperatively in both groups, and including osteophytes in the target regions, HO rates were high at 40.9% and 36.9% for the rhBMP-2/ACS and allograft groups, respectively (p = 0.350). At 24 months, the rate of HO in the rhBMP-2/ACS group was higher than in the allograft group (78.6% vs 59.2%, respectively; p < 0.001). At 24 months, the rate of superior-anterior adjacent-level Park Grade 3 HO was 4.2% in both groups, whereas the rate of Park Grade 2 HO was 19.0% in the rhBMP-2/ACS group compared with 9.8% in the allograft group. At 24 months, the rate of inferior-anterior adjacent-level Park Grade 2/3 HO was 11.9% in the rhBMP-2/ACS group compared with 5.9% in the allograft group. At 24 months, HO rates at the target implant level were similar (p = 0.963). At 24 months, the mean length and anteroposterior diameter of HO were significantly greater in the rhBMP-2/ACS group compared with the allograft group (p = 0.033 and 0.012, respectively). Regarding clinical correlation, at 24 months in both groups, Park Grade 3 HO at superior adjacent-level disc spaces significantly reduced range of motion, more so in the rhBMP-2/ACS group. At 24 months, HO negatively affected Neck Disability Index scores (excluding neck/arm pain scores), neurological status, and overall success in patients in the rhBMP-2/ACS group, but not in patients in the allograft group.
Implantation of rhBMP-2/ACS at 1.5 mg/ml with polyetheretherketone spacer and titanium plate is effective in inducing fusion and improving pain and function in patients undergoing ACDF for symptomatic single-level cervical degenerative disc disease. At 24 months, the rate and dimensions (length and anteroposterior diameter) of HO were higher in the rhBMP-2/ACS group. At 24 months, range of motion was reduced, with Park Grade 3 HO in both treatment groups. The impact of Park Grades 2 and 3 HO on Neck Disability Index success, neurological status, and overall success was not consistent among the treatment groups. The study data may offer a deeper understanding of HO after ACDF and may pave the way for improved device designs.
Clinical trial registration no.: IDE# G060021; data compared with pooled data from control arms of IDE# G010188/NCT00642876 and IDE# G000123/NCT00437190 (www.clinicaltrials.gov).
Paul M. Arnold, Zoher Ghogawala and Candan Tamerler
Lindsay Tetreault, Jefferson R. Wilson, Mark R. N. Kotter, Aria Nouri, Pierre Côté, Branko Kopjar, Paul M. Arnold and Michael G. Fehlings
The minimum clinically important difference (MCID) is defined as the minimum change in a measurement that a patient would identify as beneficial. Before undergoing surgery, patients are likely to inquire about the ultimate goals of the operation and of their chances of experiencing meaningful improvements. The objective of this study was to define significant predictors of achieving an MCID on the modified Japanese Orthopaedic Association (mJOA) scale at 2 years following surgery for the treatment of degenerative cervical myelopathy (DCM).
Seven hundred fifty-seven patients were prospectively enrolled in either the AOSpine North America or International study at 26 global sites. Fourteen patients had a perfect preoperative mJOA score of 18 and were excluded from this analysis (n = 743). Data were collected for each participating subject, including demographic information, symptomatology, medical history, causative pathology, and functional impairment. Univariate log-binominal regression analyses were conducted to evaluate the association between preoperative clinical factors and achieving an MCID on the mJOA scale. Modified Poisson regression using robust error variances was used to create the final multivariate model and compute the relative risk for each predictor.
The sample consisted of 463 men (62.31%) and 280 women (37.69%), with an average age of 56.48 ± 11.85 years. At 2 years following surgery, patients exhibited a mean change in functional status of 2.71 ± 2.89 points on the mJOA scale. Of the 687 patients with available follow-up data, 481 (70.01%) exhibited meaningful gains on the mJOA scale, whereas 206 (29.98%) failed to achieve an MCID. Based on univariate analysis, significant predictors of achieving the MCID on the mJOA scale were younger age; female sex; shorter duration of symptoms; nonsmoking status; a lower comorbidity score and absence of cardiovascular disease; and absence of upgoing plantar responses, lower-limb spasticity, and broad-based unstable gait. The final model included age (relative risk [RR] 0.924, p < 0.0001), smoking status (RR 0.837, p = 0.0043), broad-based unstable gait (RR 0.869, p = 0.0036), and duration of symptoms (RR 0.943, p = 0.0003).
In this large multinational prospective cohort, 70% of patients treated surgically for DCM exhibited a meaningful functional gain on the mJOA scale. The key predictors of achieving an MCID on the mJOA scale were younger age, shorter duration of symptoms, nonsmoking status, and lack of significant gait impairment.