Pathogenesis and Staging of Craniovertebral Tuberculosis: Radiographic Evaluation, Classification, and Natural History.

STUDY DESIGN: Retrospective cohort. OBJECTIVE: To radiographically evaluate Craniovertebral junction (CVJ) tuberculosis infection pathogenesis and to propose a modification to the Lifeso classification. METHODS: A cohort of patients with radiologically or microbiologically identified CVJ tuberculosis treated at a single tertiary referral center in a TB endemic area was queried for characteristics about clinical presentation, treatment, and radiographic evidence of bone destruction and abscess formation were included. Disease was classified according to the Lifeso grading system and bony lesions were classified as either type 1 (preservation of underlying structure) or type 2 (damage of underlying structure). RESULTS: 52 patients were identified (mean age 28.5 ± 13.4yr, 48% male; 14% with a prior history of tuberculosis). All presented with neck pain at presentation, 29% with rotatory pain, and 37% with myelopathy. Comparison by Lifeso type showed Lifeso III lesions had longer symptom durations (P = .03) and more commonly had periarticular or predental abscess formation (P < .05), spinal cord compression (P < .01), and more commonly involved the C2 body and atlanto-dental joint. Underlying bony destruction was more common for lesions of the lateral atlantoaxial joints and atlanto-dental joints in Lifeso III cases than in either Lifeso I or II (all P < .05). CONCLUSIONS: The radiologic findings of the present series suggest CVJ TB infection may originate in the periarticular fascia with subsequent invasion into the adjacent atlanto-dental and lateral atlantoaxial joints in later disease. To reflect this proposed etiology, we present a modified Lifeso classification to describe the radiologic pathogenesis of CVJ TB.

Application of the modified lifeso radiographic staging system to the management and outcomes for craniocervical tuberculosis.

OBJECTIVE: To describe a management algorithm for cervicovertebral junction (CVJ) TB based upon disease severity and neurological status at presentation. METHODS: Retrospective cohort study of 52 patients treated for microbiologically or clinically-diagnosed CVJ TB at a tertiary referral center in a TB endemic area were identified. Data were gathered about presenting symptoms, baseline neurological status, management strategy, and management outcomes. Patients were categorized by a modified Lifeso Stage. RESULTS: Fifty-two patients were included (Mean age 28.5 ± 13.4 yr, 48% male): 18 Lifeso Stage I, 15 Stage II, and 19 Stage III. All presented with pain, 19 (37%) with neurological symptoms, and 5 with inability to ambulate. Stage II and III patients were more commonly myelopathic at presentation (p < 0.01) than Stage I patients. Only Stage II/III lesions required traction or surgical intervention; Stage III lesions more commonly required surgery than Stage II lesions (100% vs. 73%; p = 0.03). Among surgically-treated Stage II and III lesions, Stage III lesions had longer symptom prodromes (5.1 ± 2.2 vs. 3.3 ± 1.4mo; p = 0.03), more commonly had lateral mass collapse at presentation (58 vs. 9%; p = 0.02), and more commonly required occipitocervical fusion (68 vs. 9%; p < 0.01). CONCLUSION: Based upon these data, Stage I lesions may be treated conservatively, unless presenting with a neurological deficit. Conversely, Stage III lesions require open reduction and instrumentation due to irrevocable underlying bony damage. Reducible Stage II lesions with absent or mild neurological symptoms can be treated conservatively, but irreducible lesions and those with concomitant neurological deficits merit surgery.

Spinal deformity surgery is accompanied by serious complications: report from the Morbidity and Mortality Database of the Scoliosis Research Society from 2013 to 2020.

PURPOSE: The Morbidity and Mortality (M&M) report of the Scoliosis Research Society (SRS) has been collected since 1965 and since 1968 submission of complications has been required of all members. Since 2009, the SRS has collected information on death, blindness, and neurological deficit, with acute infection being added in 2012 and unintentional return to the operating room (OR) being added in 2017. In this report, we use the most recent data submitted to the SRS M&M database to determine the rate of neurological deficit, blindness, acute infection, unintentional return to the OR, and death, while also comparing this information to previous reports. METHODS: The SRS M&M database was queried for all cases from 2013 to 2020. The rates of death, vision loss, neurological deficit, acute infection, and unintentional return to the OR were then calculated and analyzed. The rates were compared to previously published data if available. Differences in complication rates between years were analyzed with Poisson regression with significance set at α = 0.05. RESULTS: The total number of cases submitted per year varied with a maximum of 49,615 in 2018 and a minimum of 40,464 in 2020. The overall reported complication rate from 2013 to 2020 was 2.86%. The overall mortality rate ranged from 0.09% in 2018 to 0.14% in 2015. The number of patients with visual impairment ranged from 4 to 13 between 2013 and 2015 (no data on visual impairment were collected after 2015). The overall infection rate varied from 0.95 in 2020 to 1.30% in 2015. When the infection rate was analyzed based on spinal deformity group, the neuromuscular scoliosis group consistently had the highest infection rate ranging from 3.24 to 3.94%. The overall neurological deficit rate ranged from 0.74 to 0.94%, with the congenital kyphosis and dysplastic spondylolisthesis groups having the highest rates. The rates of unintentional return to the OR ranged from 1.60 to 1.79%. Multiple groups showed a statistically significant decreasing trend for infection, return to the operating room, neurologic deficit, and death. CONCLUSIONS: Neuromuscular scoliosis had the highest infection rate among all spinal deformity groups. Congenital kyphosis and dysplastic spondylolisthesis had the highest rate of neurological deficit postoperatively. This is similar to previously published data. Contrary to previous reports, neuromuscular scoliosis did not have the highest annual death rate. Multiple groups showed a statistically significant decreasing trend in complication rates during the reporting period, with only mortality in degenerative spondylolisthesis significantly trending upwards. LEVEL OF EVIDENCE: Level III.

Malignant peripheral nerve sheath tumor of the sciatic nerve presenting with leg pain in the setting of lumbar scoliosis and spinal stenosis.

STUDY DESIGN: Case report. OBJECTIVE: We present a case of malignant peripheral nerve sheath tumor (MPNST) presenting as neuropathic pain in the setting of lumbar scoliosis and spinal stenosis. Most peripheral nerve sheath tumors are benign, and malignant cases are more commonly associated with neurofibromatosis type 1 or prior radiation exposure. MPNST is a rare tumor with a poor prognosis. We report a case of MPNST that presented as neuropathic pain following lumbar decompression and fusion surgery. METHODS: A 60-year-old woman presented for management of lumbar scoliosis, stenosis, and left leg pain. After lumbar decompression and fusion surgery, the patient was readmitted to the hospital after falling 10 weeks post-op. She reported gradual recurrence of leg pain. Left foot drop was noted on exam. Imaging studies showed no spinal changes postoperatively or residual stenosis. Obesity limited electrodiagnostic studies. Hip MRI revealed a lobular soft tissue mass in the left sciatic notch. Surgical resection and pathology provided the diagnosis of MPNST. The patient declined wide resection and other interventions after seeking a second opinion. Palliative pain management was implemented. RESULTS: The patient expired 15 months after her index spinal surgery. CONCLUSIONS: MPNST is an extremely rare tumor that can present with symptoms similar to radiculitis. Clinical signs and symptoms of MPNST are vague and nonspecific due to compression of surrounding structures. Surgical wide resection is the first line of treatment for MPNST with chemotherapy and radiotherapy as adjuvant treatments. MPNST has a poor prognosis with reported 5-year survival ranging from 16 to 54%. This case demonstrates the need to pursue additional workup when diagnostic imaging and objective findings do not satisfactorily explain the clinical presentation. LEVEL OF EVIDENCE: IV.

Use of Intravenous Tranexamic Acid Improves Early Ambulation After Total Knee Arthroplasty and Anterior and Posterior Total Hip Arthroplasty.

We conducted a retrospective cohort study (N = 477) to determine if use of intravenous tranexamic acid (TXA) improves early ambulation and reduces blood loss after total knee arthroplasty and anterior and posterior total hip arthroplasty. Mean (SD) patient age was 66.5 (10.1) years. For all 3 procedures, early ambulation was significantly better in the TXA group than in the no-TXA group at postoperative days 1 and 2, and, over time, reductions in hemoglobin and hematocrit were statistically significantly lower in the TXA group than in the no-TXA group. TXA groups required fewer postoperative transfusions. Incidence of postoperative venous thromboembolism was similar between all groups. TXA use improves early ambulation after total joint arthroplasty.

Acute Renal Infarction After Lateral Lumbar Interbody Spinal Fusion for Kyphoscoliosis.

STUDY DESIGN: Case report. OBJECTIVES: Case report of acute renal infarction following lateral interbody fusion with posterior instrumentation for adult lumbar kyphoscoliosis. SUMMARY OF BACKGROUND DATA: This is the first reported renal infarction following minimally invasive lateral interbody fusion and posterior spinal instrumentation. METHODS: We report a case of acute renal infarction in a 72-year-old woman following direct lateral interbody fusion (DLIF) with percutaneous pedicle screw and rod fixation from L1 to L5 for correction of kyphoscoliosis. She reported vague abdominal pain on postoperative day (POD) 7. Abdominal ultrasound findings revealed no abnormalities. The patient tolerated a regular diet, improved in rehabilitative modalities, and had stable vital signs. Abdominal computed tomographic (CT) scan on POD 9 for persistent abdominal pain revealed right renal infarction and right renal artery occlusion. The patient was transferred to the ICU for evaluation, where intravenous heparin was administered and no reperfusion was performed. Transesophageal echocardiography on POD 14 revealed moderate diffuse plaque in the descending aorta. RESULTS: Surgical correction of kyphoscoliosis through DLIF and posterior spinal instrumentation was performed with improvement of deformity. Subsequent acute renal infarction was noted. The patient was discharged home on POD 21. There were no further adverse events up to the 1-year follow-up. CONCLUSIONS: A lateral approach to the anterior lumbar spine may precipitate renal artery occlusion and renal infarction in patients with atherosclerosis. Diagnosis of renal infarction requires a high index of suspicion because the primary complaint may be vague back, flank, and abdominal pain. We emphasize the importance of recognizing potential symptoms early to prevent additional renal injury. Caution should be taken with deformities around the origin of the renal arteries and great vessels, especially in patients with atherosclerosis. LEVEL OF EVIDENCE: Level IV.

Is it safe to back out pedicle screws after augmentation with polymethyl methacrylate or calcium phosphate cement? A biomechanical study.

STUDY DESIGN: Biomechanical cadaveric study. OBJECTIVE: To determine the torque required to remove pedicle screws augmented with polymethyl methacrylate (PMMA) or calcium phosphate cement (CPC); thus, proving the safety of back out of augmented screws in the osteopotoric model, which would be a more dangerous setting than the nonosteoporotic model. SUMMARY OF BACKGROUND DATA: To our knowledge, no earlier study has characterized the safety of backing out pedicle screw augmented with PMMA or CPC. METHODS: Pedicle screws were inserted in 24 osteoporotic vertebrae (48 pedicles). The maximal insertion torque and pullout strength of each screw were recorded. After pullout of the pedicle screws, the vertebrae were then randomized into 2 groups of 12 (24 pedicles) each. PMMA was injected into the pedicles in the first group and CPC was injected into the second group after which the pedicle screws were inserted. The pedicle screws were inserted into the pedicle holes augmented with PMMA or CPC, respectively. Finally, all augmented screws were backed out and the maximal removal torque was recorded using a digital torque wrench. RESULTS: Throughout the study, no incidence of pedicle or lamina fractures was observed. The average insertion torque was 0.5±0.27 and 0.45±0.29 N·m for groups 1 and 2, respectively (P=0.724). The average pullout strength was 723.1±391.7 and 671.2±383.0 N (P=0.950). After cement augmentation, the average removal torque was 0.77±0.31 and 0.81±0.26 N·m for PMMA and CPC, respectively (P=0.494). CONCLUSIONS: The results of this study showed that pedicle screws can be easily and safely backed out after augmentation with PMMA or CPC. The result of CPC, however, may only be valid before any bony ingrowth.

Functional and radiological outcomes of 360 degrees fusion of three or more motion levels in the lumbar spine for degenerative disc disease.

STUDY DESIGN: This is a single-center, multisurgeon, retrospective study of radiologic and functional outcome measures at a minimum 2-year follow-up. OBJECTIVE: We studied the radiologic and functional outcomes following 3 or more motion segment fusions of the lumbar spine for low back pain due to multilevel degenerative disc disease. SUMMARY OF BACKGROUND DATA: Good functional outcomes have been reported for 1 or 2-level fusions, but there are no reports dealing specifically with 3 or more level fusions. METHODS: A total of 80 adult patients met the inclusion/exclusion criteria of multilevel (3 or more motion segments) 360 degrees fusion for lumbar degenerative disc disease, failed nonoperative treatment for at least 1 year, no previous lumbar fusion, no fracture, tumor or infection of the spine, completed preoperative and postoperative functional questionnaires including SF-36 (n = 80), Oswestry (n = 69), Roland Morris (n = 68), and radiologic evaluation of fusion solidity with a minimum follow-up of 2 years. RESULTS: The average patient age was 57 years (range, 27-81). The mean follow-up was 4 years (2-7). On average, patients had fusion of 4 motion segments (range, 3-8 levels). Solid arthrodesis at the first surgery was achieved in 65/80 (81%). Adjacent segment degeneration was noted in 11 patients. Of these, 5 had undergone an extension of their fusion within the study period. There were no deaths or neurologic complications. Deep wound infection occurred in 2 patients, neither requiring implant removal. The Oswestry Disability Index scores improved from 49.8 to 35.1 (29.5%) (P < 0.001). The Roland Morris scores improved from 17.6 to 12.2 (30.7%) (P < 0.001). For the SF-36 scales, significant (P < 0.001) improvement was seen in all scales except Role Emotional scores and Mental Composite Scales. CONCLUSION: The surgical treatment of lumbar degenerative disc disease by 360 degrees fusion should be considered for properly selected patients. The goal of surgery is reduction, not elimination of disability.

Enhancement of periprosthetic bone quality with topical hydroxyapatite-bisphosphonate composite.

BACKGROUND: Implant loosening is associated with inflammatory bone loss induced by ultra-high molecular weight polyethylene wear debris. We hypothesized that a hydroxyapatite-bisphosphonate composite improves periprosthetic bone quality and osseous integration of an intramedullary implant even in the presence of ultra-high molecular weight polyethylene particles in an experimental rat femur model. METHODS: A preliminary in vitro study determined the optimal concentration of zoledronate (50 microM) that would maximally decrease osteoclasts without harming osteoblasts. Hydroxyapatite-coated intramedullary nails were implanted bilaterally in the femora of sixteen rats (the control group), and hydroxyapatite-zoledronate-coated nails were implanted bilaterally in the femora of sixteen rats (the experimental group). Ultra-high molecular weight polyethylene particles were introduced into the femoral canal before implantation. Eight rats from each group were killed at six weeks, and the remaining rats were killed at six months. Periprosthetic bone mass was analyzed by dual x-ray absorptiometry and microcomputed tomography. Osseous integration was examined by biomechanical testing of pullout strength. RESULTS: The mean bone area (and standard deviation) in the periprosthetic bone region was significantly greater (p < 0.0001) in the hydroxyapatite-zoledronate group (2.388 +/- 0.960 mm2) than in the control group (0.933 +/- 0.571 mm2). This difference was larger in the six-week group than in the six-month group (p = 0.03). The average peak pullout force for the treated femora (241.0 +/- 95.1 N) was significantly greater (p < 0.0001) than that for the controls (55.6 +/- 49.0 N). This difference was similar in the six-week and six-month groups. The energy required for nail pullout was significantly greater (p < 0.0001) for the treated femora (521.6 +/- 293.8 N-mm) than for the controls (142.2 +/- 152.1 N-mm). This difference in energy to pullout was similar in the six-week and six-month groups. Regression analysis demonstrated a high correlation between periprosthetic bone mass and peak pullout force for both the six-week (r = 0.766, p = 0.0005) and six-month (r = 0.838, p < 0.0001) groups. CONCLUSIONS: Surface modification of implants with hydroxyapatite-zoledronate improves periprosthetic bone quality and osseous integration. CLINICAL RELEVANCE: Hydroxyapatite-based site-specific delivery of bisphosphonates may be one way of reducing ultra-high molecular weight polyethylene wear particle-induced periprosthetic osteolysis and implant loosening.

Bisphosphonates may reduce recurrence in giant cell tumor by inducing apoptosis.

Giant cell tumor of bone is an aggressive tumor characterized by extensive bone destruction and high recurrence rates. This tumor consists of stromal cells and hematopoietic cells that interact in an autocrine manner to produce tumoral osteoclastogenesis and bone resorption. This autocrine regulation may be disrupted by novel therapeutic agents. Nonspecific local adjuvant therapies such as phenol or liquid nitrogen have been used in the treatment of giant cell tumor, but specific adjuvant therapies have not been described. The bisphosphonates pamidronate and Zoledronate can induce apoptosis in giant cell tumor culture in a dose-dependent manner. We established giant cell tumor cultures from patients with extensive destruction of bone. One of the four cultures formed osteoclastlike giant cells in vitro after more than six passages without exogenous receptor activator of NF-kappaB ligand or macrophage colony stimulating factor. Annexin V staining, presence of active cleaved form of caspase-3, and disappearance of poly (ADP-ribose) polymerase on Western blotting indicated activation of apoptosis by bisphosphonates in giant cell tumor. These results indicate that topical or systemic use of pamidronate or zoledronate can be a novel adjuvant therapy for giant cell tumor by targeting osteoclastlike giant cells, mononuclear giant cell precursor cells, and the autocrine loop of tumor osteoclastogenesis.

Treatment of allograft nonunions with recombinant human bone morphogenetic proteins (rhBMP).

Fractures and nonunions are the main complications associated with bone allografts. Although the osteogenic role of recombinant human bone morphogenetic proteins (rhBMPs) has been demonstrated in experimental models and human tibial nonunions, the results are unknown for allograft nonunions. In this study, the efficacy of rhBMPs was evaluated in nonunions of femoral allografts. The results of six allograft nonunions in five patients who underwent resection of malignant bone tumours and allograft bone transplantation were analysed one to five years following application of rhBMPs at the nonunion site. There were two osteoarticular allografts and three intercalary allografts. Of three intercalary allografts, one demonstrated nonunion at both ends. Four patients received adjuvant chemotherapy and three had additional radiation therapy. There were two allograft fracture nonunions and four nonunions at the allograft-host junction. Two allograft fracture nonunions and one nonunion at the allograft-host junction were treated with 12 mg of rhBMP-2. The remaining three nonunions were treated with 7 mg of rhBMP-7 (Osigraft). The outcome and radiological evidence of healing were evaluated at a minimal follow-up of twelve months. There was neither healing of allograft fractures nor union of allograft-host junction. There was elongation or enlargement of the callus from the host. One patient continued to develop resorption of the allograft, which led to allograft fracture. Two patients who were treated with rhBMP-7 and corticocancellous allografts developed sterile drainage. There was no tumour recurrence with the use of rhBMPs after a mean follow-up of 39+/-25 months. rhBMP's alone were not sufficient to achieve healing in allograft nonunions and fractures following wide resection including periosteum and soft tissues.

Do donor characteristics really matter? Short- and long-term impact of donor characteristics on recipient survival, 1995-1999.

We reviewed the impact of multiple donor characteristics on recipient mortality by univariate and multivariate analyses in a cohort of heart donors from 1995 to 1999. A sub-cohort of donors was also selected who met "marginal" criteria, and the early and late survival of these patients was then compared. Surrogates of donor size (donor weight, donor body mass index [BMI], BMI mismatch >20%), under-resuscitation (hematocrit, 24-hour fluid intake) and age >56 years were significantly associated with peri-operative mortality in the univariate analysis; in the multivariate analysis, only average donor heart rate at procurement (p =.001), donor hematocrit (p =.02) and donor weight (p =.05) were significantly associated. Few donor characteristics actually impact significantly on recipient outcome, and thus recipient characteristics may figure more prominently than those of the donor toward the risk of death after transplantation.