Lateral lumbar interbody fusion using a cellular allogeneic bone matrix in the treatment of symptomatic degenerative lumbar disc disease and lumbar spinal instability.

BACKGROUND: Cellular allogeneic bone grafts are used as a biologic adjuvant in lumbar spinal fusions. The clinical use of a minimally invasive extreme lateral approach to the lumbar spine has been widely adopted; however, there are few clinical studies that have documented the clinical and radiographic outcomes associated with the use of cellular allografts as an adjunct to fusion in this advanced surgical approach. METHODS: A consecutive series of 67 patients (34 males and 33 females) with a mean age of 66.8 years (26-85 years) who underwent single- or multilevel lateral lumbar interbody fusion (LLIF) with supplemental posterior segmental spinal fixation using a cellular allogeneic bone matrix as the only bone graft material was retrospectively reviewed by a single surgeon. Patients' preoperative and 3- and 12-month postoperative data were studied. All patients were followed for a minimum of 12 months. Standardized clinical outcome measures-36-Item Short Form Surgery (SF-36), Oswestry Disability Index (ODI), and visual analog scale (VAS) back and leg pain scores-were used to evaluate the clinical outcomes. An average of 2.25 levels was treated per patient (151 total levels). Fusion status was assessed by dynamic radiographs and computed tomography (CT) scans. The statistical method used to identify the significance of the observed changes in clinical outcomes was the paired 2-sided t-tests. Significance was ascribed to P values <0.05. RESULTS: Fusion was achieved at 142 levels (142/151; 94%). Eight levels (8/151; 5.3%) showed partial fusions and one patient (single level) had no fusion. In the group of patients with fusions, the mean back and leg pain scores showed improvement from preoperative scores at both 3 and 12 months (P<0.001). Functional outcomes showed similar clinical success in both in SF-36 and ODI scores. CONCLUSIONS: The use of a cellular allogeneic bone matrix provided osteoconductive and osteoinductive components for successful spine fusions and was associated with statistically significant improvement in SF-36, VAS, and ODI scores.

Transforaminal Lumbar Interbody Fusion With Viable Allograft: 75 Consecutive Cases at 12-Month Follow-up.

BACKGROUND: When conservative treatments fail to alleviate the discomfort of abnormal motion, spinal fusion has been shown to provide symptomatic treatment for spinal instability, stenosis, spondylolisthesis, and symptomatic degenerative disc disease. The trend and rates of fusion over the past few years have been dramatic in the United States. Accompanying that higher incidence has been the shifting from traditional open surgery to minimally invasive techniques to reduce scar tissue formation, extent of muscle stripping, and muscle retraction which all have been shown to adversely affect outcomes. Other reasons supporting the widespread transition to minimally invasive surgical (MIS) techniques include decreased postoperative pain, decreased intraoperative blood loss, shorter postoperative hospital stay, faster return to normal activity, and reduced reoperation rates. Spinal fusion procedures rely on a bony fusion substrate in addition to fixation hardware. While available grafting options include autogenous, allogeneic, and synthetic materials, recent interest in viable allograft material with living cells has drawn attention and attraction for incorporating a biologic basis for regenerative consideration. A recent viable allograft, complete with cellular and designated bone carrier (VIA Graft, Vivex Biomedical, Marietta, Georgia) has been developed. This study represents a retrospective review of a single-practice, single-surgeon evaluation of the product in 75 consecutive patients for fusion by computed tomography (CT) and radiographic evaluation at 12 months in conjunction with a MIS approach. Viable allograft was used to fill the peri-implant space, and central implant lumen was filled with a cancellous bone sponge soaked in perivertebral bone marrow. Posterolateral supplementation was attained with beta-tricalcium phosphate as a bulking agent. METHODS: A retrospective review identified patients treated for both primary and revision surgery who received VIA Graft cellular bone matrix material in minimally invasive interbody fusion (MIS-TLIF) with a minimum of 12-month follow up. The patient diagnoses included radiculopathy in all instances and varied collateral indications such as foraminal collapse, recurrent disc herniation, and spondylolisthesis to which pain and morbidity had been unresolved by conservative treatment. Adverse events including infection, revisions, and evidence of immune response were evaluated and patient comorbidities defined for the entire population of patients. Patient fusion status was assessed using thin slice CT by 2 independent radiologists separate from the surgeon. There were 75 consecutive adult patients with degenerative conditions of the lumbar spine who underwent MIS-TLIF surgery of which 40 (53%) were male and 35 (47%) were female. Mean age, height, and weight were 58 years, 170.18 cm (67 in), and 88.45 kg (195 lbs), respectively. The mean body mass index was 30. There were 16 patients (21%) who smoked and 12 (16%) with a history of diabetes. Independent blinded review of fusion was obtained by a board certified musculoskeletal radiologist and an experienced board certified orthopaedic surgeon to assess patient fusion status. Spinal segments were deemed fused if 12-month CT scans demonstrated evidence of bridging bone at the fusion site without observed motion on flexion-extension radiographs. Findings such as osteolysis around the implant or pedicle screws, extensive endplate cystic changes, or linear defects parallel to the endplates through intradiscal new bone formation were interpreted as signs of pseudarthrosis. Interobserver and intraobserver error and κ assessments were analyzed to assure agreement in the CT outcomes assessment where interpretation of κ were as follows: <0.00 = poor agreement, 0.00-0.20 = slight agreement, 0.21-0.40 = fair agreement, 0.41-0.60 = moderate agreement, 0.61-0.80 = substantial agreement, and 0.81-1.00 = almost perfect agreement. Differences were resolved by consensus amongst the observers. RESULTS: In total, 96% of the 75 patients with a total of 85 levels (96.5% of levels treated) achieved a fusion at 12 months. There were no perioperative or latent complications and no transfusions in all 75 patients. CONCLUSIONS: In this population, 96% of the patients treated achieved the surgical objective in 96.5% of the levels treated. LEVEL OF EVIDENCE: IV. CLINICAL RELEVANCE: The high rate of fusion, the lack of secondary morbidity with autologous bone harvest, and the clinical success account for the benefits of viable allograft matrix for MIS-TLIF use.

Safety and feasibility of outpatient ACDF in an ambulatory setting: A retrospective chart review.

BACKGROUND: Outpatient spinal surgery is becoming increasingly common and in some areas is now the preferred course for certain procedures. Many different procedures, including ACDF, have been examined in the outpatient setting in the past few years but to our knowledge none have included the ambulatory setting. METHODS: All ACDF procedures performed during the time frame of the study were included. Charts were pulled and evaluated using the outcome measures. One and two-level ACDF were divided into respective cervical levels and individually analyzed. RESULTS: Single level ACDF comprised 62% (n = 74) of the total surgeries. Single level ACDF patients averaged a total hospital stay time of 4.7 hours, with a maximum total stay time of 8.2 hours and a minimum stay time of 0.8 hours. Two-level ACDF made up 38% (n = 45) of the total surgeries. The average total stay time for two level ACDF was 5.4 hours, with a maximum time of 9.6 hours and a minimum of 3.4 hours. All patients were comparable in age and gender. There were no major operating complications and neither re-admissions nor deaths after discharge. There were two transfers from ambulatory surgical centers to inpatient status for observation only. CONCLUSIONS: Outpatient one and two-level ACDF with plate fixation can safely be done on an outpatient ambulatory basis. The data suggest that all subaxial cervical levels can be treated. Patient fusion and satisfaction data were not obtained and thus cannot be commented upon. CLINICAL RELEVANCE: Ambulatory ACDF should be considered as a feasible option for reducing hospital stay as well as the associated healthcare costs.