Keitaro Matsukawa, Takashi Kato, Ralph Mobbs, Yoshiyuki Yato and Takashi Asazuma
Lumbosacral fixation plays an important role in the management of devastating spinal pathologies, including osteoporosis, fracture, infection, tumor resection, and spinal deformities, which require long-segment fusion constructs to the sacrum. The sacral-alar-iliac (SAI) screw technique has been developed as a promising solution to facilitate both minimal invasiveness and strong fixation. The rationale for SAI screw insertion is a medialized entry point away from the ilium and in line with cranial screws. The divergent screw path of the cortical bone trajectory (CBT) provides a higher amount of cortical bone purchase and strong screw fixation and has the potential to harmoniously align with SAI screws due to its medial starting point. However, there has been no report on the combination of these two techniques. The objective of this study was to assess the feasibility of this combination technique.
The subjects consisted of 17 consecutive patients with a mean age of 74.2 ± 4.7 years who underwent posterior lumbosacral fixation for degenerative spinal pathologies using the combination of SAI and CBT fixation techniques. There were 8 patients with degenerative scoliosis, 7 with degenerative kyphosis, 1 with an osteoporotic vertebral fracture at L5, and 1 with vertebral metastasis at L5. Fusion zones included T10–sacrum in 13 patients, L2–sacrum in 2, and L4–sacrum in 2.
No patients required complicated rod bending or the use of a connector for rod assembly in the lumbosacral region. Postoperative CT performed within a week after surgery showed that all lumbosacral screws were in correct positions and there was no incidence of neurovascular injuries. The lumbosacral bone fusion was confirmed in 81.8% of patients at 1-year follow-up based on fine-cut CT scanning. No patient showed a significant loss of spinal alignment or rod fracture in the lumbosacral transitional region.
This is the first paper on the feasibility of a combination technique using SAI and CBT screws. This technique could be a valid option for lumbosacral fixation due to the ease of rod placement with potential reductions in operative time and blood loss.
Ralph J. Mobbs, Marc Coughlan, Robert Thompson, Chester E. Sutterlin III and Kevin Phan
There has been a recent renewed interest in the use and potential applications of 3D printing in the assistance of surgical planning and the development of personalized prostheses. There have been few reports on the use of 3D printing for implants designed to be used in complex spinal surgery.
The authors report 2 cases in which 3D printing was used for surgical planning as a preoperative mold, and for a custom-designed titanium prosthesis: one patient with a C-1/C-2 chordoma who underwent tumor resection and vertebral reconstruction, and another patient with a custom-designed titanium anterior fusion cage for an unusual congenital spinal deformity.
In both presented cases, the custom-designed and custom-built implants were easily slotted into position, which facilitated the surgery and shortened the procedure time, avoiding further complex reconstruction such as harvesting rib or fibular grafts and fashioning these grafts intraoperatively to fit the defect. Radiological follow-up for both cases demonstrated successful fusion at 9 and 12 months, respectively.
These cases demonstrate the feasibility of the use of 3D modeling and printing to develop personalized prostheses and can ease the difficulty of complex spinal surgery. Possible future directions of research include the combination of 3D-printed implants and biologics, as well as the development of bioceramic composites and custom implants for load-bearing purposes.
Ralph J. Mobbs, Monish Maharaj and Prashanth J. Rao
Despite limited availability and the morbidity associated with autologous iliac crest bone graft (ICBG), its use in anterior lumbar interbody fusion (ALIF) procedures remains the gold standard to achieve arthrodesis. The search for alternative grafts yielding comparable or superior fusion outcomes with fewer complications continues. In particular, i-FACTOR, a novel bone graft substitute composed of anorganic bone matrix (ABM) with P-15 small peptide, is one example currently used widely in the dental community. Although preclinical studies have documented its usefulness, the role of i-FACTOR in ALIF procedures remains unknown.
The authors' goal was to determine the safety and efficacy of i-FACTOR bone graft composite used in patients who underwent ALIF by evaluating fusion rates and clinical outcomes.
A nonblinded cohort of patients who were all referred to a single surgeon's practice was prospectively studied. One hundred ten patients with degenerative spinal disease underwent single or multilevel ALIF using the ABM/P-15 bone graft composite with a mean of 24 months (minimum 15 months) of follow-up were enrolled in the study. Patient's clinical outcomes were assessed using the Oswestry Disability Index for low-back pain, the 12-Item Short Form Health Survey, Odom's criteria, and a visual analog scale for pain. Fine-cut CT scans were used to evaluate the progression to fusion.
All patients who received i-FACTOR demonstrated radiographic evidence of bony induction and early incorporation of bone graft. At a mean of 24 months of follow-up (range 15–43 months), 97.5%, 81%, and 100% of patients, respectively, who had undergone single-, double-, and triple-level surgery exhibited fusion at all treated levels. The clinical outcomes demonstrated a statistically significant (p < 0.05) difference between preoperative and postoperative Oswestry Disability Index, 12-Item Short Form Health Survey, and visual analog scores.
The use of i-FACTOR bone graft substitute demonstrates promising results for facilitating successful fusion and improving clinical outcomes in patients who undergo ALIF surgery for degenerative spinal pathologies.
Anthony M. T. Chau, Lileane L. Xu, Rhys van der Rijt, Johnny H. Y. Wong, Cristian Gragnaniello, Ralph E. Stanford and Ralph J. Mobbs
Autologous bone from the iliac crest is commonly used for spinal fusion. However, its use is associated with significant donor site morbidity, especially pain. Reconstructive procedures of the iatrogenic defect have been investigated as a technique to alleviate these symptoms. The goal of this study was to assess the effects of reconstruction versus no reconstruction following iliac crest harvest in adults undergoing spine surgery.
The authors searched the Cochrane Central Register of Controlled Trials (The Cochrane Library 2011, Issue 4); MEDLINE (1948–Oct 2011); EMBASE (1947–Oct 2011); and the reference lists of articles. Randomized controlled trials (RCTs) or nonrandomized controlled trials (NRCTs) were included in the study. Two independent reviewers selected the studies, extracted data using a standardized collection form, and assessed for risk of bias.
Three RCTs (96 patients) and 2 NRCTs (82 patients) were included. These had a moderate to high risk of bias. The results suggest that iliac crest reconstruction may be useful in reducing postoperative pain, minimizing functional disability, and improving cosmesis. No pattern of other clinical, radiological, or resource outcomes was identified.
Although the available evidence is suboptimal, this systematic review supports the notion that iliac crest reconstruction following harvest for spinal fusion may reduce postoperative pain, minimize functional disability, and improve cosmesis.
Ralph Jasper Mobbs, Jane Li, Praveenan Sivabalan, Darryl Raley and Prashanth J. Rao
The development of minimally invasive surgical techniques is driven by the quest for better patient outcomes. There is some evidence for the use of minimally invasive surgery for degenerative lumbar spine stenosis (LSS), but there are currently no studies comparing outcomes with matched controls. The object of this study was to compare outcomes following minimally invasive unilateral laminectomy for bilateral decompression (ULBD) to a standard “open” laminectomy for LSS.
The authors conducted a prospective, 1:1 randomized trial comparing ULBD to open laminectomy for degenerative LSS. The study enrolled 79 patients between 2007 and 2009, and adequate data for analysis were available in 54 patients (27 in each arm of the study). Patient demographic characteristics and clinical characteristics were recorded and clinical outcomes were obtained using pre- and postoperative Oswestry Disability Index (ODI) scores, visual analog scale (VAS) scores for leg pain, patient satisfaction index scores, and postoperative 12-Item Short Form Health Survey (SF-12) scores.
Significant improvements were observed in ODI and VAS scores for both open and ULBD interventions (p < 0.001 for both groups using either score). In addition, the ULBD-treated patients had a significantly better mean improvement in the VAS scores (p = 0.013) but not the ODI scores (p = 0.055) compared with patients in the open-surgery group. ULBD-treated patients had a significantly shorter length of postoperative hospital stay (55.1 vs 100.8 hours, p = 0.0041) and time to mobilization (15.6 vs 33.3 hours, p < 0.001) and were more likely to not use opioids for postoperative pain (51.9% vs 15.4%, p = 0.046).
Based on short-term follow-up, microscopic ULBD is as effective as open decompression in improving function (ODI score), with the additional benefits of a significantly greater decrease in pain (VAS score), postoperative recovery time, time to mobilization, and opioid use.