Comparative Analysis of Vascular Structures in OLIF51 and the Lateral Corridor Approach under Supine MRI and Intraoperative Enhanced CT in the Lateral Decubitus Position.

Background and Objectives: As the oblique lateral interbody fusion at L5/S1 (OLIF51) and the lateral corridor approach (LCA) have gained popularity, an understanding of the precise vascular structure at the L5/S1 level is indispensable. The objectives of this study were to investigate the vascular anatomy at the L5/S1 level, and to compare the movement of vascular tissue between the supine and lateral decubitus positions using intraoperative enhanced CT and MRI. Materials and Methods: A total of 43 patients who underwent either OLIF51 or LCA were investigated with an average age at surgery of 60.4 (37-80) years old. The preoperative MRI was taken to observe the axial and sagittal anatomy of the vascular position under the supine position. The intraoperative vein-enhanced CT was taken just before incision in the right decubitus position, and compared to supine MRI anatomy. Iliolumbar vein appearance and its types were also classified. Results: The average vascular window allowed for OLIF51 was 22.8 mm and 34.1 mm at either the L5 caudal endplate level or the S1 cephalad endplate level, respectively. The LCA was 14.2 mm and 12.6 mm at either level, respectively. The left common iliac vein moved 3.8 mm and 6.9 mm to the right direction at either level from supine to the right decubitus position, respectively. The bifurcation moved 6.3 mm to the caudal direction from supine to right decubitus. The iliolumbar vein was located at 31 mm laterally from the midline, and the MRI detection rate was 52%. Conclusions: The precise measurement of vascular anatomy indicated that the OLIF51 approach was the standard minimally invasive anterior approach for the L5/S1 disc level compared to LCA; however, there were many variations in quantitative anatomy as well as significant vascular movements between the supine and right decubitus positions. In the clinical setting of OLIF51 and LCA surgeries, careful preoperative evaluation and intraoperative 3D imaging are recommended for safe and accurate surgery.

Clinical and Radiologic Analysis of Minimally Invasive Anterior-Posterior Combined Surgery for Adult Spinal Deformity: Comparison of Oblique Lateral Interbody Fusion at L5/S1 (OLIF51) versus Transforaminal Interbody Fusion.

Background and Objectives: Although adult spinal deformity (ASD) surgery brought about improvement in the quality of life of patients, it is accompanied by high invasiveness and several complications. Specifically, mechanical complications of rod fracture, instrumentation failures, and pseudarthrosis are still unsolved issues. To better improve these problems, oblique lateral interbody fusion at L5/S1 (OLIF51) was introduced in 2015 at my institution. The objective of this study was to compare the clinical and radiologic outcomes of anterior-posterior combined surgery for ASD between the use of OLIF51 and transforaminal interbody fusion (TLIF) at L5/S1. Materials and Methods: A total of 117 ASD patients received anterior-posterior correction surgeries either with the use of OLIF51 (35 patients) or L5/S1 TLIF (82 patients). In both groups, L1-5 OLIF and minimally invasive posterior procedures of hybrid or circumferential MIS were employed. The sagittal and coronal spinal alignment and spino-pelvic parameters were recorded preoperatively and at follow-up. The quality-of-life parameters and visual analogue scale were evaluated, as well as surgical complications at follow-up. Results: The average follow-up period was thirty months (13-84). The number of average fused segments was eight (4-12). The operation time and estimated blood loss were significantly lower in OLIF51 than in TLIF. The PI-LL mismatch, LLL, L5/S1 segmental lordosis, and L5 coronal tilt were significantly better in OLIF51 than TLIF. The complication rate was statistically equivalent between the two groups. Conclusions: The introduction of OLIF51 for adult spine deformity surgery led to a decrease in operation time and estimated blood loss, as well as improvement in sagittal and coronal correction compared to TLIF. The circumferential MIS correction and fusion with OLIF51 serve as an effective surgical modality which can be applied to many cases of adult spinal deformity.

Nationwide Survey of the Surgical Complications Associated with Lateral Lumbar Interbody Fusion in 2015-2020.

Introduction: Lateral lumbar interbody fusion (LLIF) has been introduced in Japan in 2013. Despite the effectiveness of this procedure, several considerable complications have been reported. This study reported the results of a nationwide survey performed by the Japanese Society for Spine Surgery and Related Research (JSSR) on the complications associated with LLIF performed in Japan. Methods: JSSR members conducted a web-based survey following LLIF between 2015 and 2020. Any complications meeting the following criteria were included: (1) major vessel, (2) urinary tract, (3) renal, (4) visceral organ, (5) lung, (6) vertebral, (7) nerve, and (8) anterior longitudinal ligament injury; (9) weakness of psoas; (10) motor and (11) sensory deficit; (12) surgical site infection; and (13) other complications. The complications were analyzed in all LLIF patients, and the differences in incidence and type of complications between the transpsoas (TP) and prepsoas (PP) approaches were compared. Results: Among the 13,245 LLIF patients (TP 6,198 patients [47%] and PP 7,047 patients [53%]), 389 complications occurred in 366 (2.76%) patients. The most common complication was sensory deficit (0.5%), followed by motor deficit (0.43%) and weakness of psoas muscle (0.22%). Among the patient cohort, 100 patients (0.74%) required revision surgery during the survey period. Almost half of the complications developed in patients with spinal deformity (183 patients [47.0%]). Four patients (0.03%) died from complications. Statistically more frequent complications occurred in the TP approach than in the PP approach (TP vs. PP, 220 patients [3.55%] vs. 169 patients [2.40%]; p<0.001). Conclusions: The overall complication rate was 2.76%, and 0.74% of the patients required revision surgery because of complications. Four patients died from complications. LLIF may be beneficial for degenerative lumbar conditions with acceptable complications; however, the indication for spinal deformity should be carefully determined by the experience of the surgeon and the extent of the deformity.

Protective Attitudes toward Occupational Radiation Exposure among Spine Surgeons in Japan: An Epidemiological Description from the Survey by the Society for Minimally Invasive Spinal Treatment.

Background and Objectives: The global trend toward increased protection of medical personnel from occupational radiation exposure requires efforts to promote protection from radiation on a societal scale. To develop effective educational programs to promote radiation protection, we clarify the actual status and stage of behavioral changes of spine surgeons regarding radiation protection. Materials and Methods: We used a web-based questionnaire to collect information on the actual status of radiation protection and stages of behavioral change according to the transtheoretical model. The survey was administered to all members of the Society for Minimally Invasive Spinal Treatment from 5 October to 5 November 2020. Results: Of 324 members of the Society for Minimally Invasive Spinal Treatment, 229 (70.7%) responded. A total of 217 participants were analyzed, excluding 12 respondents who were not exposed to radiation in daily practice. A trunk lead protector was used by 215 (99%) participants, while 113 (53%) preferred an apron-type protector. Dosimeters, thyroid protector, lead glasses, and lead gloves were used by 108 (50%), 116 (53%), 82 (38%), and 64 (29%) participants, respectively. While 202 (93%) participants avoided continuous irradiation, only 120 (55%) were aware of the source of the radiation when determining their position in the room. Regarding the behavioral change stage of radiation protection, 134 (62%) participants were in the action stage, while 37 (17%) had not even reached the contemplation stage. Conclusions: We found that even among the members of the Society for Minimally Invasive Spinal Treatment, protection of all vulnerable body parts was not fully implemented. Thus, development of educational programs that cover the familiar risks of occupational radiation exposure, basic protection methods in the operating room, and the effects of such protection methods on reducing radiation exposure in actual clinical practice is warranted.

Comparative Clinical Analysis of Oblique Lateral Interbody Fusion at L5/S1 versus Minimally Invasive Transforaminal Interbody Fusion (MIS-TLIF) for Degenerative Lumbosacral Disorders.

Introduction: Since 2015, we have performed minimally invasive oblique lateral interbody fusion (OLIF) at L5/S1 for various lumbosacral spine disorders using percutaneous pedicle screws. This study evaluated the clinical and radiologic results between OLIF at L5/S1 and minimally invasive transforaminal interbody fusion (MIS-TLIF) for single to multilevel degenerative lumbosacral disorders. Methods: A total of 124 patients underwent either OLIF (62 cases) or MIS-TLIF (62 cases). The applied disorders were L5 isthmic spondylolisthesis, foraminal stenosis, pseudarthrosis, adjacent segment degeneration, a combination of L4/5 and L5/S1 pathology, and others. We performed OLIF with posterior percutaneous fixation in the same lateral position. MIS-TLIF was performed with modified cortical bone trajectory screws. The operation time (OT), estimated blood loss (EBL), JOABPEQ effectiveness rate (%),Visual Analog Scale (VAS), fusion rate, radiologic segmental alignment, and complications were evaluated. Results: The average follow-up periods were 51 and 69 months (24-95) in the OLIF and MIS-TLIF groups, respectively. Furthermore, the average fused segments were 1.6 and 1.5 in each group, respectively. The OT and EBL per segment were 130 min and 56 mL and 100 min and 64 mL, respectively. The JOABPEQ effectiveness rate in the OLIF group demonstrated a statistically higher value in the domains of pain, low-back function, and gait than the MIS-TLIF group (P<0.01). The follow-up VAS of low-back pain (LBP) and lower extremity numbness had lower values in the OLIF group (P<0.05). The fusion rates were 98% and 90%, respectively. Segmental lordosis at L5/S1 was significantly larger in the OLIF group (15° vs. 11°, P<0.01). Conclusions: The OLIF group demonstrated less pain as well as better low-back and gait functions at follow-up. The minimally invasive anterolateral fusion employing OLIF at L5/S1 using percutaneous screws serves as a viable and effective procedure with less residual LBP and high fusion rate.

Minimally Invasive Spinal Treatment (MIST)-A New Concept in the Treatment of Spinal Diseases: A Narrative Review.

In the past two decades, minimally invasive spine surgery (MISS) techniques have been developed for spinal surgery. Historically, minimizing invasiveness in decompression surgery was initially reported as a MISS technique. In recent years, MISS techniques have also been applied for spinal stabilization techniques, which were defined as minimally invasive spine stabilization (MISt), including percutaneous pedicle screws (PPS) fixation, lateral lumbar interbody fusion, balloon kyphoplasty, percutaneous vertebroplasty, cortical bone trajectory, and cervical total disc replacement. These MISS techniques typically provide many advantages such as preservation of paraspinal musculature, less blood loss, a shorter operative time, less postoperative pain, and a lower infection rate as well as being more cost-effective compared to traditional open techniques. However, even MISS techniques are associated with several limitations including technical difficulty, training opportunities, surgical cost, equipment cost, and radiation exposure. These downsides of surgical treatments make conservative treatments more feasible option. In the future, medicine must become "minimally invasive" in the broadest sense-for all patients, conventional surgeries, medical personnel, hospital management, nursing care, and the medical economy. As a new framework for the treatment of spinal diseases, the concept of minimally invasive spinal treatment (MIST) has been proposed.

A New Treatment Algorithm That Incorporates Minimally Invasive Surgery for Pyogenic Spondylodiscitis in the Thoracic and Lumbar Spines: The Results of Its Clinical Application to a Series of 34 Patients.

Background and Objectives: Spinal minimally invasive surgery (MIS) experts at the university hospital worked as a team to develop a new treatment algorithm for pyogenic spondylodiscitis in lumbar and thoracic spines. They modified a flow chart introduced for this condition in a pre-MIS era to incorporate MIS techniques based on their extensive experiences accumulated over the years, both in MIS for degenerative lumbar diseases and in the treatment of spine infections. The MIS procedures incorporated in this algorithm consisted of percutaneous pedicle screw (PPS)-rod fixation and transpsoas lateral lumbar interbody fusion (LLIF). The current study analyzed a series of 34 patients treated with prospective selection of the methods according to this new algorithm. Materials and Methods: The algorithm first divided the patients into those who had escaped complicated disease conditions, such as neurologic impairment, extensive bone destruction, and the need to be mobilized without delay (Group 1) (19), and those with complicated pyogenic spondylodiscitis (Group 2) (15). Group 1 had image-guided needle biopsy followed by conservative treatment alone with antibiotics and a spinal brace (12) (Group 1-A) or a subsequent addition of non-fused PPS-rod fixation (7) (Group 1-B). Group 2 underwent an immediate single-stage MIS with non-fused PPS-rod fixation followed by posterior exposure for decompression and debridement through a small midline incision (12) (Group 2-A) or an additional LLIF procedure after an interval of 3 weeks (3) (Group 2-B). Results: All patients, except four, who either died from causes unrelated to the spondylodiscitis (2) or became lost to follow up (2), were cured of infection with normalized CRP at an average follow up of 606 days (105-1522 days). A solid interbody fusion occurred at the affected vertebrae in 15 patients (50%). Of the patients in Group 2, all but two regained a nearly normal function. Despite concerns about non-fused PPS-rod instrumentation, only seven patients (21%) required implant removal or replacement. Conclusions: Non-fused PPS-rod placements into infection-free vertebrae alone or in combination with posterior debridement through a small incision worked effectively in providing local stabilization without contamination of the metal implant from the infected tissue. MIS LLIF allowed for direct access to the infected focus for bone grafting in cases of extensive vertebral body destruction.

Association of occupational direct radiation exposure to the hands with longitudinal melanonychia and hand eczema in spine surgeons: a survey by the society for minimally invasive spinal treatment (MIST).

PURPOSE: To investigate the association between occupational direct radiation exposure to the hands and longitudinal melanonychia (LM) and hand eczema in spine surgeons. METHODS: A web-based questionnaire survey of the Society for Minimally Invasive Spinal Treatment (MIST) in Japan was conducted. The proportion of LM and hand eczema in hands with high and low-radiation exposure was compared using Fisher's exact test. The odds ratios (ORs) and their 95% confidence intervals (CIs) for the prevalence of LM and hand eczema in the high-radiation exposure hands were calculated using generalized estimating equations for logistic regression as control for the correlation of observations among the same individuals and possible confounders. RESULTS: Among 324 members of the society, responses were received from 229 members (70.7%). A total of 454 hands from 227 participants were analysed. The prevalence of LM and hand eczema was 43% and 29%, respectively. In a hand-by-hand comparison, more hands had LM in the high-radiation exposure group than the low-radiation exposure group (90 [40%] vs. 39 [17%], respectively, p < 0.001). A similar trend was observed for hand eczema (63 [28%] vs. 33 [15%], respectively, p = 0.001). The adjusted OR for high-radiation exposure hands was 3.18 (95% CI: 2.24-4.52). Consistent results were obtained for hand eczema, with an adjusted OR of 2.26 (95% CI: 1.67-3.06). CONCLUSION: The present study suggests that direct radiation exposure to physician's hands is associated with LM and hand eczema. Those with LM and radially biased hand eczema may have had high direct radiation exposure.

Rod contour and overcorrection are risk factors of proximal junctional kyphosis after adult spinal deformity correction surgery.

PURPOSE: To examine the risk factors of proximal junctional kyphosis (PJK) after surgery for adult spinal deformity (ASD) focusing on rod contour. METHODS: Sixty-three patients with ASD who underwent surgery using lateral lumbar interbody fusion and percutaneous pedicle screws were analyzed. Fixation range was from the lower thoracic spine to the pelvis in all cases. Patients were divided into two groups. The PJK group consisted of 16 patients with PJK. The non-PJK group had 47 patients without PJK. We examined various spinopelvic parameters and parameters related to rod contour. RESULTS: Among the various spinal and pelvic parameters, those in the PJK group were significantly larger in terms of preoperative SVA and were significantly smaller in terms of postoperative "PI-LL." For parameters related to rod contour, the rod kyphotic curve at the thoracic spine in the PJK group was significantly less than that in the non-PJK group. The inclination of the pedicle screw at the upper instrumented vertebra (UIV) was significantly more cranial in the PJK group than in the non-PJK group. The kyphotic curve of the rod at the UIV was more parallel in the PJK group than in the non-PJK group. On logistic regression analysis, insufficient kyphotic curve at the thoracic spine along with UIV and overcorrection of the lumbar spine were identified as significant risk factors. CONCLUSIONS: Insufficient kyphotic curve of the rod in the thoracic spine along with UIV and overcorrection of the lumbar spine were noted as significant risk factors of PJK.

Technical and Conceptual Review on the L5-S1 Oblique Lateral Interbody Fusion Surgery (OLIF51).

Lumbar lateral interbody fusion (LLIF) has been gaining popularity among the spine surgeons dealing with degenerative spinal diseases while LLIF on L5-S1 is still challenging for its technical and anatomical difficulty. OLIF51 procedure achieves effective anterior interbody fusion based on less invasive anterior interbody fusion via bifurcation of great vessels using specially designed retractors. The technique also achieves seamless anterior interbody fusion when combined with OLIF25. A thorough understanding of the procedures and anatomical features is mandatory to avoid perioperative complications.

Clinical and radiologic comparison of anterior-posterior single-position lateral surgery versus MIS-TLIF for degenerative lumbar spondylolisthesis.

BACKGROUND: The lateral interbody fusion (LIF) has gained popularity for the surgical treatment of lumbar degenerative spondylolisthesis (DS), however, LIF often requires the position change for posterior screwing. We have performed the single-position lateral surgery of oblique lateral interbody fusion (OLIF) and posterior screwing (OLIF-LPF). The present study compared the clinical and radiologic results between OLIF-LPF and minimally invasive transforaminal interbody fusion (MIS-TLIF). METHODS: A total of 142 patients underwent either OLIF-LPF (92 cases) or MIS-TLIF (50 cases) for L3 or L4 DS. The average age was 72 and 70 years old, respectively. The OLIF-LPF was performed in right decubitus position with allograft and percutaneous modified cortical bone trajectory screws (mCBT). The MIS-TLIF utilized a single 4 cm midline incision, allograft, boomerang cage and mCBTs. The operation time, estimated blood loss, and serum CRP levels were recorded. JOABPEQ effectiveness rate (%), Visual Analogue Scale (VAS), fusion rate, segmental radiologic alignment, and complications were also evaluated. RESULTS: Average follow-up period was 31 and 57 months in OLIF-LPF and MIS-TLIF, respectively. The average operation time and estimated blood loss were 108min, 51 ml and 104 min and 69 ml, respectively. OLIF-LPF demonstrated significantly higher values of mental health domain of JOABPEQ effectiveness rate and VAS improvement of leg pain than those in MIS-TLIF. The less correction loss of posterior disc height was demonstrated in OLIF-LPF. The fusion rate and symptomatic adjacent segment degeneration (ASD) were statistically equivalent between two groups. CONCLUSIONS: The single-position surgery of OLIF combined with posterior screwing serves as a safe, minimally invasive and effective surgical modality without the need of position change. It provides comparable fusion rate, segmental radiologic alignment, and symptomatic adjacent segment degeneration to MIS-TLIF surgery.

Risk Factor Analysis of Proximal Junctional Kyphosis after Surgical Treatment of Adult Spinal Deformity with Oblique Lateral Interbody Fusion.

STUDY DESIGN: A single-center retrospective study. PURPOSE: To investigate the prevalence of proximal junctional kyphosis (PJK) and its risk factors after surgical treatment of adult spinal deformity (ASD) with oblique lateral interbody fusion (OLIF). OVERVIEW OF LITERATURE: Correction of ASD using OLIF has been developed because it is less invasive, and enables correction of severe deformities. Although PJK is a well-recognized complication after the correction of spinal deformity, few studies have evaluated the prevalence and risk factors for PJK after OLIF for ASD. METHODS: We reviewed 74 patients who underwent surgery for ASD. PJK was defined as a proximal junction sagittal Cobb angle exceeding 10°, and at least 10° greater than the preoperative measurement. We investigated the following as risk factors: age, sex, body mass index, medical history, number of fused segments, number of interbody fusions, number of OLIFs, number of osteotomies, level of upper instrumented vertebrae, lowest instrumented vertebrae, and radiographic parameters. RESULTS: The mean follow-up duration was 22.4 months and the mean age of the patients was 73.6 years. PJK was present in 19/74 patients (25.7%) and absent in 55/74 (74.3%). In the univariate analysis, those with PJK had a significantly higher proportion of patients with a history of vertebral compression fracture (7/19 patients [36.8%] vs. 6/55 patients [10.9%], p=0.027). Those with PJK had a significantly higher proportion of patients with fusion to the pelvis (18/19 patients [94.7%] vs. 34/55 patients [61.8%], p=0.016). According to the multivariate analysis, fusion to the pelvis was a significant risk factor for PJK. CONCLUSIONS: Fusion to the pelvis was the most important risk factor for PJK. A history of vertebral compression fracture served as an additional risk factor for PJK. Clinicians should consider these factors before treating ASD patients with OLIF.

Comparison of Outcomes of Oblique Lateral Interbody Fusion with Percutaneous Posterior Fixation in Lateral Position and Minimally Invasive Transforaminal Lumbar Interbody Fusion for Degenerative Spondylolisthesis.

STUDY DESIGN: Single-center retrospective study. PURPOSE: To compare the physical function and quality of life (QOL) parameters of two minimally invasive surgical (MIS) procedures: oblique lateral interbody fusion with percutaneous posterior fixation in lateral position (OLIF-LPF) and minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) for single-level degenerative spondylolisthesis (DS). OVERVIEW OF LITERATURE: To date, many options for the surgical treatment of lumbar DS and reports have described the effectiveness of minimally invasive lateral access surgery and MIS-TLIF. However, there is still a paucity of comparative data regarding the physical function and QOL outcomes of OLIF and MIS-TLIF. METHODS: Eighty-six patients were enrolled in this study (group O: OLIF-LPF, n=38; group T: MIS-TLIF, n=48). We evaluated the operation time, estimated blood loss (EBL), postoperative laboratory data, preoperative and postoperative radiographic parameters, overall functional outcome with the Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ) effectiveness rate, and Visual Analog Scale (VAS) score for low back pain, leg pain, and leg numbness. RESULTS: No statistical differences in operation time, EBL, and C-reactive protein level, 5 days postoperatively, between groups O and T. With respect to radiological outcome, preoperative and postoperative disc height change was significantly greater in group O than in group T (3.8 vs. 1.8 mm, p<0.05). Both groups showed postoperative improvements in the clinical outcome scores of all JOABPEQ domains, but the effectiveness rate increase in the psychological domain was significantly higher in group O than in group T (47.1% vs. 14.6%, p<0.05). No differences in the preoperative and postoperative VAS score change were noted between the two groups in any of the items. CONCLUSIONS: The changes in physical function and QOL parameters after OLIF-LPF and MIS-TLIF were almost equivalent; however, OLIF-LPF had significant superiority in the psychological domain.

Single-level controlled comparison of OLIF51 and percutaneous screw in lateral position versus MIS-TLIF for lumbosacral degenerative disorders: Clinical and radiologic study.

BACKGROUND: We have performed minimally invasive Oblique Lateral Interbody Fusion at L5/S1 (OLIF51) and simultaneous posterior screwing in lateral position for lumbosacral disorders. This study compared the clinical and radiologic results between OLIF51 versus Minimally Invasive Transforaminal Lumbar Interbody Fusion (MIS-TLIF) in single-level fusion for lumbosacral degenerative disorders. METHODS: A total of 71 patients underwent either OLIF51 (33 cases) or MIS-TLIF (38 cases) at L5/S1 spinal segment. The average age was 64 yrs (27-88). The disorders were L5 isthmic or degenerative spondylolisthesis, foraminal stenosis, pseudarthrosis and adjacent segment degeneration, and others. Using 35 mm oblique incision, OLIF51 was performed followed by posterior percutaneous fixation in same lateral position. MIS-TLIF was performed with midline 40 mm incision and modified cortical bone trajectory (CBT) screws. The operation time, estimated blood loss, JOABPEQ effectiveness rate (%), Visual Analogue Scale (VAS), fusion rate, radiologic alignment, and complications were evaluated. RESULTS: Average follow-up period was 25 and 31 months (12-45) in OLIF51 and MIS-TLIF, respectively. The average operation time and estimated blood loss were 165min, 62 ml and 163 min and 68 ml, respectively. The JOABPEQ effectiveness rate in OLIF51 demonstrated higher value in low back function (44% vs 17%, P < 0.02). The fusion rate was 97% and 92% in OLIF51 and MIS-TLIF, respectively. The segmental lordosis was significantly larger in OLIF51 (17 vs 11 deg, P < 0.01). There were no vascular or neural complications. CONCLUSIONS: Although two groups demonstrated the equivalent surgical invasiveness, there was the significant superiority of OLIF51 in terms of low back function over MIS-TLIF. The segmental lordosis creation was also better in OLIF51. Even in the single-level lumbosacral fusion, OLIF51 serves as the safe and viable surgical procedure with use of lateral position surgery, minimizing the residual low back dysfunction.

Correlation between the Computed Tomography Values of the Screw Path and Pedicle Screw Pullout Strength: An Experimental Study in Porcine Vertebrae.

STUDY DESIGN: Biomechanical study. PURPOSE: To assess the correlation between the computed tomography (CT) values of the pedicle screw path and screw pull-out strength. OVERVIEW OF LITERATURE: The correlation between pedicle screw pull-out strength and bone mineral density has been well established. In addition, several reports have demonstrated a correlation between bone mineral density and CT values. However, no previous biomechanical studies investigated the correlation between CT values and pedicle screw pull-out strength. METHODS: Sixty fresh-frozen lumbar vertebrae from 6-month-old pigs were used. Before screw insertion, the CT values of the screw path were obtained for each sample. Specimens were then randomly divided into three equal groups. Each group had one of three pedicle screws inserted: 4.0-mm LEGACY (4.0-LEG), 4.5-mm LEGACY (4.5-LEG), or 4.5-mm SOLERA (4.5-SOL) (all from Medtronic Sofamor Danek Inc., Memphis, TN, USA). Each screw had a consistent 30-mm thread length. Axial pull-out testing was performed at a rate of 1.0 mm/min. Correlations between the CT values and pedicle screw pull-out strength were evaluated using Pearson's correlation coefficient analysis. RESULTS: The correlation coefficients between the CT values of the screw path and pedicle screw pull-out strength for the 4.0-LEG, 4.5-LEG, and 4.5-SOL groups were 0.836 (p <0.001), 0.780 (p <0.001), and 0.873 (p <0.001), respectively. Greater CT values were associated with greater screw pull-out strength. CONCLUSIONS: The CT values of the screw path were strongly positively correlated with pedicle screw pull-out strength, regardless of the screw type and diameter, suggesting that the CT values could be clinically useful for predicting pedicle screw pull-out strength.

Effect of Indirect Neural Decompression with Oblique Lateral Interbody Fusion Was Influenced by Preoperative Lumbar Lordosis in Adult Spinal Deformity Surgery.

Study Design: Retrospective clinical study on the indirect decompressive effect of oblique lateral interbody fusion (OLIF) for adult spinal deformity. Purpose: To evaluate the effect of interbody distraction by OLIF for the treatment of adult spinal deformity. Overview of Literature: Adult spinal deformity with symptomatic stenosis has been addressed conventionally using a direct posterior decompression approach with fusion. However, stenotic symptoms can also be alleviated indirectly through restoration of intervertebral and foraminal heights and correction of spinal alignment. Methods: Twenty-eight patients with adult spinal deformity underwent OLIF combined with modified cortical bone trajectory screws at 94 lumbar levels with neuromonitoring. The patients were divided into three groups based on their preoperative lumbar lordosis: group A, <0°; group B, 0°-20°; and group C, >20°. The cross-sectional area (CSA) of the thecal sac was measured preoperatively and postoperatively on axial magnetic resonance images. Differences in CSA were evaluated, and the relationship between the CSA extension ratio and preoperative CSA was assessed. Changes in disc height and segmental disc angle were measured from plain radiographs. Results: OLIFs were performed successfully without neural complications. In group A, the mean CSA increased from 120.6 mm2 preoperatively to 148.5 mm2 postoperatively (p <0.001). The mean CSA for group B increased from 120.1 mm2 preoperatively to 154.4 mm2 postoperatively (p <0.001). Group C had an increase in mean CSA from 114.7 mm2 preoperatively to 160.7 mm2 postoperatively (p <0.001). The mean CSA enlargement ratio was 27.5%, 32.1%, and 60.4% in groups A, B, and C, respectively. The mean CSA extension ratio was inversely correlated with preoperative CSA. Conclusions: The effect of indirect neural decompression in adult spinal deformity with OLIF varies with the degree of preoperative lumbar lordosis.

Clinical and Radiological Comparison between Three Different Minimally Invasive Surgical Fusion Techniques for Single-Level Lumbar Isthmic and Degenerative Spondylolisthesis: Minimally Invasive Surgical Posterolateral Fusion versus Minimally Invasive Surgical Transforaminal Lumbar Interbody Fusion versus Midline Lumbar Fusion.

STUDY DESIGN: Retrospective cohort study. PURPOSE: Comparison between three different minimally invasive surgical (MIS) fusion techniques for single-level lumbar spondylolisthesis. OVERVIEW OF LITERATURE: There has been an increase in the development and utilization of MIS techniques for lumbar spine fusion. No study has compared the efficacy of MIS-posterolateral fusion (MIS-PLF), MIS-transforaminal lumbar interbody fusion (MIS-TLIF), and midline lumbar fusion (MIDLF) with modified cortical bone trajectory screws for lumbar spondylolisthesis. METHODS: Fifty-nine patients with single-level lumbar spondylolisthesis and a minimum follow-up period of 1 year were included in this study. The MIS-PLF, MIS-TLIF, and MIDLF groups included 22, 15, and 22 patients, respectively. The average age of the groups was 70.6, 49.3, and 62.7 years, respectively. The evaluation parameters were operation time, intraoperative bleeding, serum C-reactive protein (CRP) value, creatine kinase (CK) value, and overall functional outcome as per the Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ) score. The changes in the lumbar lordosis angle (LLA), segmental disc angle (SDA), and disc height were measured. Fusion rate, screw loosening, and loss of correction were also assessed. RESULTS: MIDLF showed a significantly shorter operation time (111 min), less bleeding amount (112.5 mL), and lower values of CRP and CK than the other two techniques. There was no significant difference in the JOABPEQ scores of the three groups. MIDLF resulted in a greater increase in the LLA and SDA postoperatively. MIDLF and MIS-TLIF resulted in a significant increase in the middle disc height compared with MIS-PLF. MIDLF showed a lower loss of correction after 6 months postoperatively (2.6%) than MIS-PLF (5.2%) and MIS-TLIF (4.2%). The fusion rate was 100% in the MIDLF and MIS-TLIF groups and 90% in the MIS-PLF group. Screw loosening occurred in 10% of the MIS-PLF cases, 7.14% of the MIS-TLIF cases, and 4.76% of the MIDLF cases. CONCLUSIONS: MIDLF was the least invasive, and there was no significant difference between the three groups in terms of fusion, screw loosening, and clinical outcomes.

Video-assisted thoracoscopic surgery using mobile computed tomography: new method for locating of small lung nodules.

BACKGROUND: The O-arm is an intraoperative imaging device that can provide computed tomography images. Surgery for small lung tumors was performed based on intraoperative computed tomography images obtained using the O-arm. This study evaluated the usefulness of the O-arm in thoracic surgery. METHODS: From July 2013 to November 2013, 10 patients with small lung nodules or ground glass nodules underwent video-assisted thoracoscopic surgery using the O-arm. A needle was placed on the visceral pleura near the nodules. After the lung was re-expanded, intraoperative computed tomography was performed using the O-arm. Then, the positional relationship between the needle marking and the tumor was recognized based on the intraoperative computed tomography images, and lung resection was performed. RESULTS: In 9 patients, the tumor could be seen on intraoperative computed tomography images using the O-arm. In 1 patient with a ground glass nodule, the lesion could not be seen, but its location could be inferred by comparison between preoperative and intraoperative computed tomography images. In only 1 patient with a ground glass nodule, a pathological complete resection was not performed. There were no complications related to the use of the O-arm. CONCLUSIONS: The O-arm may be an additional tool to facilitate intraoperative localization and surgical resection of non-palpable lung lesions.

Fungal spinal infection treated with percutaneous posterolateral endoscopic surgery.

BACKGROUND: Fungal infection in the spine is rare and its treatment is challenging. Conservative treatment with antifungal drugs often fails, with the result that surgical intervention is required in many cases. Since the general conditions of patients with fungal infections is bad due to their comorbid medical problems, surgical invasiveness should be minimized. We have reported the effectiveness of posterolateral endoscopic surgery in treating pyogenic and tuberculous spondylodiscitis. This study reports the clinical results of posterolateral endoscopic surgery in treating fungal spinal infection. METHODS: Between 2001 and 2009 we used posterolateral endoscopic surgery to treat four patients with fungal spinal infection. All were males, three in their 50s, and one in his 70s. The levels of infection were L2/3 and L5/S1 in one patient each, and L3/4 in two patients. As for the Griffiths classification, there was one patient in class 1, two in class 2, and one in class 3. Postoperative follow-up periods ranged from 26 to 92 months. Treatment history before surgery, species of causative fungus, selection of antifungal drugs and their duration, blood examinations, subsidence of infection, radiographic changes of the spine, and various complications were all investigated. RESULTS: All patients had been treated with broad-spectrum antibiotics followed by anti-methicillin-resistant Staphylococcus aureus drugs for more than several months by previous doctors. From cultures of the tissues taken during endoscopic surgery, Candida species were detected in three patients and Paecilomyces species in one. After endoscopic surgery, the patients were administered antifungal drugs for 3 months, except for one patient who had a side effect. All patients showed successful subsidence of infection at the final follow-up. CONCLUSION: Fungal spinal infection occurred in patients with a lengthy use of broad-spectrum antibiotics and anti-methicillin-resistant Staphylococcus aureus drugs. Posterolateral endoscopic debridement and irrigation surgery successfully treated fungal spinal infection. This procedure is effective in treatment of fungal spinal infection with minimal invasiveness.

Anterior decompression and strut graft versus posterior decompression and pedicle screw fixation with vertebroplasty for osteoporotic thoracolumbar vertebral collapse with neurologic deficits.

BACKGROUND CONTEXT: With the increase of the elderly population, osteoporotic vertebral fractures have been frequently reported. Surgical intervention is usually recommended in osteoporotic vertebral collapse with neurologic deficits. However, very few reports on surgical interventions exist. PURPOSE: To compare surgical results of anterior and posterior procedures for treating osteoporotic thoracolumbar vertebral collapse with sustained neurologic deficits. STUDY DESIGN: Retrospective comparative study. PATIENT SAMPLE: Fifty patients who sustained osteoporotic thoracolumbar vertebral collapse with neurologic deficits were treated either by anterior decompression and strut graft (n=32) or by posterior decompression and pedicle screw fixation with vertebroplasty (n=18). OUTCOME MEASURES: Incidence of complications, sagittal Cobb angle, spinal canal encroachment, and Japanese Orthopedic Association score. METHODS: The authors retrospectively reviewed the results of a consecutive series of patients undergoing anterior decompression and strut graft or posterior decompression and pedicle screw fixation with vertebroplasty for osteoporotic thoracolumbar vertebral collapse with neurologic deficits. Operative notes, clinical charts, and radiographs were analyzed. RESULTS: Operative time was similar between the groups, but intraoperative blood loss was significantly lower in the posterior group. All patients showed neurologic recovery. No significant difference was observed in the neurologic improvement, kyphosis correction angle, and loss of correction. Perioperative respiratory complications were found in 11 patients (34%) in the anterior group. In the anterior group, early posterior reinforcement was required in patients with very low bone density below 0.60 g/cm(2) and/or in those with three segments of instrumentation for two vertebral collapses. Posterior group patients did not undergo additional surgery. CONCLUSIONS: Anterior reconstruction for osteoporotic vertebral collapse is significant because anterior elements, particularly those at the thoracolumbar junction, play a major role in load bearing. However, difficulties arise when anterior reconstruction is performed in cases with very low bone density and in those with multiple vertebral collapse.