Lateral Transpsoas Research Articles

Segmental Arteries and Veins at Higher Lumbar Levels Can Intersect the Adjacent Caudal Intervertebral Disc in the Anterior Part of the Spinal Column: A Cadaveric Analysis.

Study DesignA cadaveric study.PurposeTo investigate the anatomical features of segmental arteries and veins in the anterior part of the spinal column to prevent segmental vessel injury.Overview of LiteratureThe lateral transpsoas approach to the lumbar intervertebral discs (IVD) is associated with the risk of segmental vessel injury. Previous studies have described the vascular anatomy on the lateral part of the vertebral body. However, there are no studies that describe the segmental vessels on its anterior aspect. Here, we report the important anatomical features of the segmental arteries and veins that can intersect the anterior part of the IVD. These vessels are considered at risk of vascular injury when placing the anterior retractors during lateral lumbar interbody fusion or cutting the anterior longitudinal ligament during anterior column realignment.MethodsFive formalin-embalmed human cadavers were used. We assessed the proportion of segmental arteries and veins that intersected the IVD in the L2–L5 range and their course on the anterior part of the spinal column.ResultsThe segmental arteries and veins commonly intersect the anterior part of the IVD (artery, 28.1%; vein, 42.1%). Seven of 10 (70%) segmental arteries at L2 intersected the IVD, but only one artery intersected the IVD at L3 and L4. The proportions of segmental veins that intersected the IVD were 60%, 50%, and 16.7% at L2, L3, and L4, respectively.ConclusionsThe segmental arteries and veins frequently intersect the IVD in the anterior part of the spinal column. Therefore, it is necessary to consider these individual anatomical features to prevent vascular damage during lateral lumbar interbody fusion surgery.

Effects of Surgical Positioning on L4-L5 Accessibility and Lumbar Lordosis in Lateral Transpsoas Lumbar Interbody Fusion: A Comparison of Prone and Lateral Decubitus in Asymptomatic Adults

Lateral interbody fusion (LIF) is traditionally performed in lateral decubitus on a breaking surgical table to improve L4-L5 access. Prone transpsoas (PTP) LIF may improve sagittal alignment and facilitate single-position circumferential procedures; but may require manipulation of the iliac crest for L4-L5 accessibility. Healthy adult volunteers (n= 41) were positioned as if for surgery in right-lateral decubitus on a radiolucent breaking table, and also prone on a Jackson-style surgical frame atop a custom PTP bolster. Iliac crest distance from the L5 superior endplate, and coronal and sagittal plane alignments were measured from fluororadiographs obtained in each of 5 positions: standard lateral decubitus (LD), prone-hips and spine neutral (PR-NN), prone-hips neutral and spine coronally bent (PR-NCB), prone-hips extended and spine neutral (PR-EN), and prone-hips extended and spine coronally bent (PR-ECB). L4-L5 accessibility was lowest in prone-neutral and improved in all augmented positional configurations: PR-NN<>PR-EN<LD<PR-ECB<PR-NCB. Coronal bending with the PTP positioner created greater accessibility than that achieved by lateral decubitus breaking (PR-NCB>LD, P= 0.0480). Coronal angulations were greatest in LD, and statistically different from both prone neutral (LD>PR-NN, P < 0.0001) and prone coronally bent (LD>PR-NCB, P < 0.0001). Lordosis was greatest in extended prone positions and lowest in lateral decubitus: PR-EN>PR-ECB>PR-NCB<>PR-NN>LD. All prone positions showed significantly greater lordosis than lateral decubitus (P < 0.001). Compared with lateral decubitus, prone positioning provides equivalent or better L4-L5 LIF access around the iliac crest when a positioner is used that enables coronal bending, and improved positional lordosis, which may facilitate segmental correction and achievement of surgical alignment goals.

Broken surgical blade retrieval following lumbar discectomy through paravertebral/lateral transpsoas approach: A case report

Background: There are rare reports of broken surgical blades occurring during lumbar discectomy, and even fewer that discuss their retrieval.Case Description: While a 54-year-old male was undergoing a lumbar discectomy, the knife blade was broken. As it was difficult to retrieve the fragment through the original incision, the patient was closed, and a postoperative angio-computerized tomography (CT) was obtained. When the CT angiogram (CTA) documented the retained fragment had become lodged near the iliac vein within the psoas muscle, a second operation for blade retrieval, consisting of a paravertebral, lateral transpsoas approach, was successfully performed.Conclusion: In some cases, it is difficult to retrieve a broken scalpel blade during the index surgery. When this occurs, we would recommend closing the patient, and obtaining a CTA to better document the location of the retained foreign body. Based upon these findings, a safer second stage procedure may be performed (e.g., as in this case using a paravertebral lateral transpsoas approach) to avoid undue sequelae/morbidity.

Rhabdomyolysis after spinal fusion surgery: management schema and prevention of a catastrophic complication

Purpose Rhabdomyolysis is a clinical syndrome with the potential to cause cardiac arrhythmias, renal failure, and even death. Currently, there are no studies regarding risk factors for developing post-operative rhabdomyolysis (POR) after spinal fusion surgeries. Our objective was to study risk factors associated with, and to develop a decision-making framework for post-operative rhabdomyolysis after spinal fusion surgery. Methods We performed a retrospective cohort study of all spinal fusions of three or more levels over 2.25 years by a single surgeon at two centers. POR was defined as a creatine phosphokinase (CPK) greater than 2000 IU/L. Results 76 surgical procedures on 72 patients were identified. Rate of POR in our cohort was 22% (17/76). Male sex was associated with POR (p < 0.05). Previously validated risk factors: younger age, lower ASA score, elevated BMI, higher pre-operative creatinine, increased intraoperative blood loss, specific surgical positions, and length of surgery, were not associated with POR. In a logistic regression model, male gender increases the odds of POR in all patients 5.82-fold (p = 0.047). In patients without a second surgery within seven days, a logistic regression model suggests each additional level fused via transpsoas approach, and male gender, increases the risk of POR 1.81-times (p = 0.015), and 6.26-times (p = 0.047), respectively. In patients with posterior fusions, a logistic regression model suggests increasing the number of lateral levels fused via transpsoas approach in the same surgery, and male gender, increases the risk of POR 1.68-times and 6.34-times, respectively. In these same subgroups, increased thickness of the psoas major in lateral transpsoas fusions increased risk of POR (p = 0.023, p = 0.046, respectively). Conclusions In spinal fusions, increasing the number of lateral levels fused via transpsoas approach, and male gender, predispose patients to increased risk of POR in those without a second surgery within seven days, and in those with a simultaneous posterior fusion.

Multistage Hybrid Approach to Management of Significant Sagittal Malalignment: 2-Dimensional Operative Video.

Minimally invasive surgery (MIS) approaches for the correction of adult spinal deformity have gained popularity in the past decade. MIS approaches can result in decreased hospitalization times and decreased morbidity. However, compared to open techniques, MIS approaches are challenging in the setting of fixed sagittal deformity and strategic surgical staging. Combined MIS and miniopen techniques are described as "hybrid" techniques. We report on the surgical approach for a fixed sagittal deformity using both MIS and miniopen techniques, specifically a miniopen pedicle subtraction osteotomy (PSO) and an anterior column release (ACR). The patient gave written informed consent for surgical treatment; institutional review board approval was not required. The patient first underwent the placement of percutaneous modular pedicle screws from T12 to the pelvis as well as a mini-PSO across the previously fused L5 vertebral body, with the placement of a temporary rod. The following day, the patient underwent lateral transpsoas interbody fusion and ACR at L2/3; a percutaneous rod was then passed from T12 to the pelvis for segmental fixation. The patient recovered well and was discharged home without complication 6 d after the initial day of surgery. The combined use of surgical staging and traditional open techniques in a selective, minimalistic fashion and adherence to minimally invasive principles provide for a powerful set of surgical techniques that capitalize on less invasive approaches to deformity management. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

The anterior-to-psoas approach for interbody fusion at the L5-S1 segment: clinical and radiological outcomes.

Over the last few decades, many surgical techniques for lumbar interbody fusion have been reported. The anterior-to-psoas (ATP) approach is theoretically supposed to benefit from the advantages of both anterior and lateral approaches with similar complication rates, even in L5-S1. At this segment, the anterior lumbar interbody fusion (ALIF) requires retroperitoneal dissection and retraction of major vessels, whereas the iliac crest does not allow the lateral transpsoas approach. This study aimed to investigate clinical-radiological outcomes and complications of the ATP approach at the L5-S1 segment in a single cohort of patients. This is a prospective single-center study, conducted from 2016 to 2019. Consecutive patients who underwent ATP at the L5-S1 segment for degenerative disc disease or revision surgery after previous posterior procedures were considered for eligibility. Complete clinical-radiological documentation and a minimum follow-up of 12 months were set as inclusion criteria. Clinical patient-reported outcomes, such as the visual analog scale for low-back pain, Oswestry Disability Index, and 36-Item Short Form Health Survey (SF-36) scores, as well as spinopelvic parameters, were collected preoperatively, 6 weeks after surgery, and at the last follow-up visit. Intraoperative and perioperative complications were recorded. The fusion rate was evaluated on CT scans obtained at 12 months postoperatively. Thirty-two patients met the inclusion criteria. The mean age at the time of surgery was 57.6 years (range 44-75 years). The mean follow-up was 33.1 months (range 13-48 months). The mean pre- and postoperative visual analog scale (7.9 ± 1.3 vs 2.4 ± 0.8, p < 0.05), Oswestry Disability Index (52.8 ± 14.4 vs 22.9 ± 6.0, p < 0.05), and SF-36 (37.3 ± 5.8 vs 69.8 ± 6.1, p < 0.05) scores significantly improved. The mean lumbar lordosis and L5-S1 segmental lordosis significantly increased after surgery. The mean pelvic incidence-lumbar lordosis mismatch and pelvic tilt significantly decreased. No intraoperative complications and a postoperative complication rate of 9.4% were recorded. The fusion rate was 96.9%. One patient needed a second posterior revision surgery for residual foraminal stenosis. In the present case series, ATP fusion for the L5-S1 segment has resulted in valuable clinical-radiological outcomes and a relatively low complication rate. Properly designed clinical and comparative trials are needed to further investigate the role of ATP for different L5-S1 conditions.

45. A prospective, in-depth analysis of perioperative anterior thigh symptoms associated with a direct lateral access approach for lumbar interbody fusion

BACKGROUND CONTEXT Anterior thigh symptoms post-transpsoas lateral approach for lumbar interbody arthrodesis are well documented. Symptoms may be transient ( PURPOSE The aim of this analysis was to prospectively characterize adverse perioperative neurological changes associated with a direct lateral transpsoas retroperitoneal closed tubular retractor system. Further, provider-reported changes were compared vs subject-reported changes. STUDY DESIGN/SETTING This investigation is a prospective, multicenter, single-arm, IRB approved post-market study. PATIENT SAMPLE One hundred fifteen subjects (115), 71 females (61.7%), with a mean age of 64.0 and mean BMI of 30.8 presenting with degenerative disc disease at one or two adjacent levels from L2 to L5 were included for analysis. OUTCOME MEASURES Subjects self-reported thigh pain, hip flexion weakness, and knee extension weakness on a 100mm Visual Analog Scale. Clinical assessments including muscle strength, Achilles reflexes, patellar reflexes, and sensory testing were performed at the same time points. Multiple questions specific to lateral access not typically collected in lumbar fusion studies were included in the analysis. METHODS All outcome measures were prospectively collected at the preoperative visit, prior to hospital discharge, and at the two-week, six-week, three-month, six-month, and twelve-month postoperative visits. Data were descriptively analyzed. RESULTS Objective neurological exam showed 17 (14.8%) subjects with access-sided adverse changes from baseline at hospital discharge. These 17 included 5 (4.4%) with changes in strength, 5 (4.4%) with sensation changes, and 11 (9.6%) with reflex changes. Of these, 2 subjects had changes in both strength and reflexes; 2 had changes in both sensation and reflexes. All strength and sensation changes were resolved by 6 weeks. All reflex changes resolved by 3 months. Twenty-two subjects (19.1%) reported increased thigh pain (>20mm) at discharge. All were resolved by 3 months. Forty-four (44) subjects (38.3%) reported increased hip flexion or extension weakness (>20mm) with 29 (65.9%) resolved by 6 weeks, 37 (84.1%) resolved by 3 months, 41/45 (93.2%) resolved by 6 months, and 3 have additional follow-up pending. Of the 17 subjects with objectively identified changes, 7 also reported subjective changes. Only 2 subjects’ (11.8%) reported symptoms (weakness) correlated with objectively reported results (strength). CONCLUSIONS This unique prospective study is the first to our knowledge that captures in-depth subjective and objective thigh symptom data specific to lateral access transpsoas surgery. The perioperative results provide a rare illustration of adverse changes and their almost complete resolution within 3 months. Further research to understand the differences in clinician reported vs subject reported changes is warranted. FDA DEVICE/DRUG STATUS Duo Interbody Fusion System (Approved for this indication)

109. Radiographic predictors of indirect neural decompression in minimally invasive transpsoas lateral interbody fusion

BACKGROUND CONTEXT An advantage of lateral interbody fusion (LLIF) surgery is the resultant indirect decompression of the neural elements that occurs with disc height restoration, restoration of spinal alignment and ligamentotaxis. The degree to which indirect decompression of the spinal canal occurs varies patient to patient, and there remains no method for effectively predicting which patients will or will not respond. PURPOSE In this study, we identify pre- and postoperative predictive factors of radiographic indirect decompression of the central spinal canal. The goal is to help surgeons ascertain which patients best respond to indirect decompression in the setting of lateral interbody fusion. STUDY DESIGN/SETTING This is a retrospective evaluation of a prospectively and consecutively collected cohort of patients treated for degenerative etiologies at a single institution. PATIENT SAMPLE Patients were included if they received a minimally invasive lateral transpsoas interbody fusion by a single surgeon at our institution. Patients were treated for degenerative etiologies. OUTCOME MEASURES A retrospective evaluation of prospectively collected consecutive patients treated with LLIF surgery treated at a single institution without subsequent direct decompression was performed. Pre- and postoperative MRI imaging was used to grade canal stenosis and three-dimensional volumetric reconstructions were used to measure changes in the central canal area (CCA). METHODS Multivariate regression was used to identify predictive variables that correlated with increases in CCA. Independent assessments of canal measurements were made by a blinded board-certified neuroradiologist and a spine surgeon. RESULTS Sixty-six patients with 110 levels were treated with a mean age of 68 years. Forty-six levels (42%) were treated for DDD, 36 levels (33%) for spondylolisthesis, 11 levels (10%) for adjacent segment disease and 17 levels (15%) for deformity. Preoperatively, 19 patients had moderate (29%) and 18 had severe stenosis (27%) with the remainder having mild or no stenosis. Of these 37 patients, only 4 remained severe, 4 were moderate and the rest (78%) improved to mild or no stenosis. CCA increased 41% from a mean of 1.09 to 1.55 cm2 (p 0.05). Multivariate evaluation of predictive variables identified that preoperative anterolisthesis (p=0.002), the presence of vacuum disc phenomenon (p=0.049) and preoperative segmental lordosis (p=0.009) were independently associated with percentage increase in CCA. Age, body mass index, side of approach, pedicle screw fixation, facet grading score, presence of facet effusions, preoperative anterior and posterior disc heights, implant distance from the posterior aspect of the vertebral body and implant height all were not associated (p>0.05). CONCLUSIONS LLIF successfully achieves indirect decompression of the CCA radiographically with a mean change of 41%. Preoperative anterolisthesis on standing films, the presence of vacuum disc phenomenon on computed tomography and preoperative segmental lordosis were independently predictive factors for the percentage increase in CCA that can be achieved. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

P4. In vitro assessment of adjustable lordotic expandable lateral interbody spacers on endplate loading and lordosis correction

BACKGROUND CONTEXT Anterior column realignment is a minimally invasive technique that uses a lateral transpsoas interbody approach with anterior longitudinal ligament (ALL) release, which aims to restore sagittal alignment. Resection of the ALL enables use of expandable lateral lumbar interbody fusion (LLIF) spacers with larger implant heights and lordosis, increasing focal lordosis correction and minimizing endplate mismatch. The relationship between implant height and lordosis selection, and their effect on segmental lordosis correction and anterior-posterior endplate loading, is poorly understood. PURPOSE The aim of this study is to quantify lordosis correction and endplate force distribution using an adjustable-lordosis expandable LLIF spacer. STUDY DESIGN/SETTING In vitro human cadaveric study. PATIENT SAMPLE A total of seven cadaveric specimens. OUTCOME MEASURES Lordosis and anterior-posterior endplate forces. METHODS Seven L4–L5 cadaveric segments were used. A 55 lb axial load was applied to L4 to simulate intraoperative loads. Segments were instrumented with bilateral pedicle screws and a sequence of expandable spacers with anterior fixation at varied heights and implant lordosis (ten constructs), including (A) 0°, 6°, and 20° lordosis with intact ALL; B) 20° and 30° lordosis following ALL resection. Segmental lordosis and endplate force-maps were collected. An equivalent loading ratio (ELR=anterior load/total load*100%) was calculated; ELR=80% refers to 80% anterior and 20% posterior edge loading. ELR was statistically compared to 50%, which is equivalent anterior-posterior loading. RESULTS The mean intact L4–L5 lordosis was 11.5°±3.0°. With the ALL intact, the 20° spacer without expansion increased lordosis to 11.9°±3.6° (p>0.05). Following ALL resection, use of 20° spacer with largest expansions (14.7 and 17.4 mm) significantly increased lordosis to 19.4°±4.5° (p=0.036 and 22.5°±4.9° (p CONCLUSIONS This study suggests that expandable spacers may help to balance anterior-posterior endplate loading while maximizing lordosis correction. Following ALL release, hyperlordotic spacers do not increase anterior loading, therefore, spacers may be selected for maximum lordosis. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Release of Anterior Longitudinal Ligament in Setting of Unfavorable Vascular Anatomy for Anterior Column Realignment-Technical Note: 2-Dimensional Operative Video.

Anterior column realignment (ACR) with anterior longitudinal ligament (ALL) release from a lateral transpsoas approach is increasingly being used as a minimally invasive technique to restore lordosis. Safe execution requires a plane between the ALL and the anterior vasculature. An unfavorable plane on preoperative imaging is a contraindication to using the technique. We describe a patient undergoing multistage minimally invasive correction of a flat-back deformity who had an unfavorable plane between the ALL and vasculature at L4-5. Patient consent was provided, and Institutional Review Board approval was not required. To safely complete the ALL release and ACR, we elected to sharply incise the lateral aspect of the ligament at L4-5 with direct control of the vessels during the anterior approach for an L5-S1 anterior lumbar interbody fusion. We then moved to the lateral transpsoas approach and used controlled distraction techniques to complete the ALL release and then to complete the ACR in a standard fashion. We ultimately achieved excellent realignment with correction of the patient's flat-back deformity using minimally invasive surgical techniques while minimizing vascular risk. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

Indirect Decompression Failure After Lateral Lumbar Interbody Fusion-Reported Failures and Predictive Factors: Systematic Review.

Background:In patients with symptomatic lumbar stenosis undergoing lateral transpsoas approach for lumbar interbody fusion (LLIF) surgery, it is not always clear when indirect decompression is sufficient in order to achieve symptom resolution. Indirect decompression failure (IDF), defined as “postoperative persistent symptoms of nerve compression with or without a second direct decompression surgery to reach adequate symptom resolution,” is not widely reported. This information, however, is critical to better understand the indications, the potential, and the limitations of indirect decompression.Objective:The purpose of this study was to systematically review the current literature on IDF after LLIF.Methods:A literature search was performed on PubMed. We included randomized controlled trials and prospective, retrospective, case-control studies, and case reports. Information on sample size, demographics, procedure, number and location of involved levels, follow-up time, and complications were extracted.Results:After applying the exclusion criteria, we included 9 of the 268 screened articles that reported failure. A total of 632 patients were screened in these articles and detailed information was provided. Average follow-up time was 21 months. Overall reported incidence of IDF was 9%.Conclusion:Failures of decompression via LLIF are inconsistently reported and the incidence is approximately 9%. IDF failure in LLIF may be underreported or misinterpreted as a complication. We propose to include the term “IDF” as described in this article to differentiate them from complications for future studies. A better understanding of why IDF occurs will allow surgeons to better plan surgical intervention and will avoid revision surgery.

Surgeon and staff radiation exposure in minimally invasive spinal surgery: prospective series using a personal dosimeter.

The level of radiation awareness by surgeons and residents in spinal surgery does not match the ubiquity of fluoroscopy in operating rooms in the United States. The present method of monitoring radiation exposure may contribute to the current deficiency in radiation awareness. Current dosimeters involve a considerable lag from the time that the surgical team is exposed to radiation to the time that they are provided with that exposure data. The objective of the current study was to assess the feasibility of monitoring radiation exposure in operating room personnel during lateral transpsoas lumbar interbody fusion (LLIF) and minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) procedures by using a wearable personal device with real-time feedback. Operating room staff participating in minimally invasive surgical procedures under a single surgeon during a 6-month period were prospectively enrolled in this study. All radiation dose exposures were recorded for each member of the surgical team (surgeon, assistant surgeon, scrub nurse, and circulating nurse) using a personal dosimeter (DoseAware). Radiation doses were recorded in microsieverts (μSv). Comparisons between groups were made using ANOVA with the Tukey post hoc test and Student t-test. Thirty-nine patients underwent interbody fusions: 25 underwent LLIF procedures (14 LLIF alone, 11 LLIF with percutaneous screw placement [PSP]) and 14 underwent MI-TLIF. For each operative scenario per spinal level, the surgeon experienced significantly higher (p < 0.035) average radiation exposure (LLIF: 167.9 μSv, LLIF+PSP: 424.2 μSv, MI-TLIF: 397.9 μSv) than other members of the team, followed by the assistant surgeon (LLIF: 149.7 μSv, LLIF+PSP: 242.3 μSv, MI-TLIF: 274.9 μSv). The scrub nurse (LLIF: 15.4 μSv, LLIF+PSP: 125.7 μSv, MI-TLIF: 183.0 μSv) and circulating nurse (LLIF: 1.2 μSv, LLIF+PSP: 9.2 μSv, MI-TLIF: 102.3 μSv) experienced significantly lower exposures. Radiation exposure was not correlated with the patient's body mass index (p ≥ 0.233); however, it was positively correlated with increasing patient age (p ≤ 0.004). Real-time monitoring of radiation exposure is currently feasible and shortens the time between exposure and the availability of information regarding that exposure. A shortened feedback loop that offers more reliable and immediate data would conceivably raise the level of concern for radiation exposure in spinal surgeries and could alter patterns of behavior, leading to decreased exposures. Further studies are ongoing to determine the effect of real-time dosimetry in spinal surgery.

Diffusion Tensor Tractography of the Lumbar Nerves before a Direct Lateral Transpsoas Approach

Diffusion Tensor Tractography of the Lumbar Nerves before a Direct Lateral Transpsoas Approach

The effect of vascular approach surgeons on perioperative complications in lateral transpsoas lumbar interbody fusions

BACKGROUND CONTEXTLateral lumbar interbody fusion (LLIF) is a popular technique used in spine surgery. It is minimally invasive, provides indirect decompression, and allows for coronal plane deformity correction. Despite these benefits, the approach to LLIF has been linked to complications associated with the lumbosacral plexus and vascular anatomy. As a result, vascular surgeons may be recruited for the exposure portion of the procedure. PURPOSEThe purpose of this study was to compare exposure-related complication and postoperative (postop) neuropraxia rates between exposure (EXP) and spine surgeon only (SSO) groups while performing the approach for LLIF. STUDY DESIGN/SETTINGRetrospective analysis of patients treated at a single institution. PATIENT SAMPLEPatients undergoing LLIF procedures between 2012 and 2018. OUTCOME MEASURESOperative time, estimated blood loss, fluoroscopy, length of stay (LOS), intra- and postoperative complications, and physiologic measures including pre- and postoperative motor examinations and unresolved neuropraxia. METHODSPatients who underwent LLIF were separated into EXP and SSO groups based on the presence or absence of vascular/general surgeon during the approach. The entire clinical history of patients with a decrease in pre- and postop motor examination was reviewed for the presence of neuropraxia. All other intra- and postop exposure-related complications were recorded for comparison. Propensity score matching (PSM) was performed to account for age, Charlson Comorbidity Index (CCI) percentage of LLIFs including L4–L5, and number of levels fused. Independent t test and chi-square analyses were used to identify significant differences between EXP and SSO groups. Statistical significance was set at p<.05. RESULTSTwo hundred and seventy-five patients underwent LLIF procedures, 155 SSO and 120 EXP. Postoperatively, 26 patients (11.1%) experienced a drop in any Medical Research Council (MRC) score, and two patients (0.7%) experienced unresolved quadriceps palsies. The mean recovery time for MRC scores was 84.4 days. Other complications included 2 pneumothoraces (0.7%), 1 iliac vein injury (0.4%), 14 cases of ileus (5.1%), 3 pulmonary emboli (1.1%), 2 deep vein thrombosis (0.7%), 3 cases of abdominal wall paresis (1.1%), and one abdominal hematoma (0.4%). After PSM, demographics including age, gender, body mass index, CCI, levels fused, and operative time were similar between cohorts. Twenty patients had changes in pre- to postop motor scores (SSO 9.4%, EXP 12.4%, p>.05). Iliopsoas motor scores decreased at the highest rate (EXP 12.4%, SSO 8.2%, p>.05) followed by quadriceps (EXP 5.2%, SSO 4.7%, p>.05). One SSO patient's postop course was complicated by a foot drop but returned to baseline within 1 year. One patient in EXP group developed an unresolved quadriceps palsy (EXP 1.0%, SSO 0.0%, p>.05). Intraoperative exposure complications included one pneumothorax (EXP 1.0%, SSO 0.0%, p>.05). There were no differences in PE/DVT, Ileus, or LOS. In the EXP cohort, three patients experienced abdominal wall paresis (EXP 2.9%, SSO 0.00%, p=.246). CONCLUSIONSComparing the LLIF exposures performed by EXP and SSO, we found no significant difference in the rates of complications. Additional research is needed to determine the etiology of the abdominal wall complications. In conclusion, neuropraxia- and approach-related complications are similarly low between exposure and spine surgeons.

Clinical Effectiveness of Pre-operative Methadone in Single Level Lateral Transpsoas Interbody Fusions

Clinical Effectiveness of Pre-operative Methadone in Single Level Lateral Transpsoas Interbody Fusions

Minimally invasive lateral transpsoas approach for lumbar corpectomy and stabilization

Background:Here, we present our experience with the minimally invasive (MI) transpsoas approach for lumbar corpectomy and stabilization. Transpsoas approach accesses the lumbar spine and includes both the direct lateral interbody fusion and extreme lateral interbody fusion techniques. Both procedures utilize a tubular retractor system which facilitates adequate retraction and direct visualization of the target, while supposedly reducing soft tissue trauma.Case Description:We evaluated two patients, one with a traumatic L2 wedge compression fracture and the other with an L3 pathological compression fracture due to multiple myeloma. Both patients underwent MI transpsoas lumbar corpectomy, anterior column reconstruction with an expandable cage, and posterior pedicle screw instrumentation to correct a kyphotic deformity. Both patients were mobilized on the 1st postoperative day and experienced significant postoperative pain relief.Conclusion:In two cases involving L2 and L3 compression fractures, MI transpsoas lumbar corpectomy was safely performed, with reduced perioperative and postoperative morbidity. Here, the transpsoas approach also allowed for early mobilization, adequate postoperative biomechanical stability, and resulted in immediate good outcomes.

Clinical and Radiological Results After Minimally Invasive Transpsoas Lateral Access Surgery for Degenerative Lumbar Stenosis.

Study Design:Prospective cohort study.Objective:The lateral transpsoas access is a retroperitoneal approach for the lumbar spine to perform the lateral lumbar interbody fusion (LLIF), an intersomatic arthrodesis performed with a cage placed on the lateral borders of the epiphyseal ring. The procedure can be used to provide indirect decompression of the nervous structures through the discectomy and restoration of the disc height. The objective of the present study was to evaluate the indirect decompression following LLIF both with radiological and clinical parameters.Methods:Prospective clinical and radiological study in a single center with 20 patients diagnosed with 1- or 2-level degenerative lumbar stenosis. Radiological analysis on magnetic resonance imaging included foramen height, canal area, canal diameter, and disc height. Clinical outcomes included visual analogue scale (VAS) and Oswestry Disability Index (ODI) collected up to 12 months. Complications and reoperations were recorded.Results:In total, 25 levels were treated. No reoperation was required. Disc height was increased by an average of 25% (P < .001). The canal area increased from 109 to 149 mm2 (P < .001) and from 9.3 to 12.2 mm (P < .001) in anteroposterior diameter. The foramen area demonstrated the effect of indirect decompression on both sides (P < .001). The height of the foramen showed significant average increase of 2.8 mm (P < .001). The results from VAS and ODI questionnaires confirmed the clinical effect of indirect decompression.Conclusion:We observed that indirect decompression by the LLIF method is feasible both radiologically and clinically with a low rate of complications and reoperations.

Outcome After Extreme Lateral Transpsoas Approach: Corpectomies Versus Interbody Fusion

The lateral transpsoas approach (LTPA) has gained popularity in thoracolumbar spine surgery procedures; however, there is an insufficient amount of data pertaining to motor and sensory complications that arise when a corpectomy is performed through the LTPA approach. Patients who underwent a corpectomy through a LTPA at a single institution between 2006 and 2016 were analyzed. Demographics, neurological outcomes, and complications were recorded. The minimum follow-up was 6 months. Univariate analysis was performed to compare demographics, surgical characteristics, complications, and outcome scores. To compare categorical variables, the χ2 test was used. For continuous outcomes, simple linear regression was used. Statistical significance was set at P < 0.05. A total of 166 patients were included. The patients were divided into 2 groups; LTPA without corpectomy (n= 112) versus LTPA with corpectomy (n=54). Patients without corpectomy showed a significantly lower rate of postoperative infections compared with patients with corpectomy (3.6% vs. 22.2%; P < 0.000). A higher percentage of postoperative complications wasfound in patients with corpectomy (31.5% vs. 13.4%; P= 0.006). Therate of neurologic complications at the 6-month follow-up and the reoperation rate (22.7% vs. 32.4%; P= 0.256) were higher in the corpectomy group (8.9% vs. 7.4%; P= 0.741), no significant difference was found between the groups. Patients who underwent an LTPA corpectomy have a higher risk to suffer from postoperative complications. The results at the 6-month follow-up did not significantly differ between the groups.

Cost Analysis of Single-Level Lumbar Fusions.

Study Design:Cost analysis of a retrospectively identified cohort of patients who had undergone primary single-level lumbar fusion at a single institution’s orthopedic or neurosurgery department.Objective:The purpose of this article is to analyze the determinants of direct costs for single-level lumbar fusions and identify potential areas for cost reduction.Methods:Adult patients who underwent primary single-level lumbar fusion from fiscal years 2008 to 2012 were identified via administrative and departmental databases and were eligible for inclusion. Patients were excluded if they underwent multiple surgeries, had previous surgery at the same anatomic region, underwent corpectomy, kyphectomy, disc replacement, surgery for tumor or infection, or had incomplete cost data. Demographic data, surgical data, and direct cost data in the categories of supplies, services, room and care, and pharmacy, was collected for each patient.Results:The cohort included 532 patients. Direct costs ranged from $8286 to $73 727 (median = $21 781; mean = $22 890 ± $6323). Surgical approach was an important determinant of cost. The mean direct cost was highest for the circumferential approach and lowest for posterior instrumented spinal fusions without an interbody cage. The difference in mean direct cost between transforaminal lumbar interbody fusions, anterior lumbar interbody fusions, and lateral transpsoas fusions was not statistically significant. Surgical supplies accounted for 44% of direct costs. Spinal implants were the primary component of supply costs (84.9%). Services accounted for 38% of direct costs and were highly dependent on operative time. Comorbidities were an important contributor to variance in the cost of care as evidenced by high variance in pharmacy costs and length of stay related to their management.Conclusion:The costs of spinal surgeries are highly variable. Important cost drivers in our analysis included surgical approach, implants, operating room time, and length of hospital stay. Areas of high cost and high variance offer potential targets for cost savings and quality improvements.

Decreased estimated blood loss in lateral trans-psoas versus anterior approach to lumbar interbody fusion for degenerative spondylolisthesis

The goal of the current study was to compare the perioperative and post-operative outcomes of eXtreme lateral trans-psoas approach (XLIF) versus anterior lumbar interbody fusion (ALIF) for single level degenerative spondylolisthesis. The ideal approach for degenerative spondylolisthesis remains controversial. Consecutive patients undergoing single level XLIF (n=21) or ALIF (n=54) for L4-5 degenerative spondylolisthesis between 2008-2012 from a single academic center were retrospectively reviewed. Groups were compared for peri-operative data (estimated blood loss, operative time, adjunct procedures or additional implants), radiographic measurements (L1-S1 cobb angle, disc height, fusion grade, subsidence), 30-day complications (infection, DVT/PE, weakness/paresthesia, etc.), and patient reported outcomes (leg and back Numerical Rating Scale, and Oswestry Disability Index). Estimated blood loss was significantly lower for XLIF [median 100; interquartile range (IQR), 50-100 mL] than for ALIF (median 250; IQR, 150-400 mL; P<0.001), including after adjusting for significantly higher rates of posterior decompression in the ALIF group. There were no significant differences in rates of complications within 30 days, radiographic outcomes, or in re-operation rates. Both groups experienced significant pain relief post-operatively. The lateral trans-psoas approach is associated with diminished blood loss compared to the anterior approach in the treatment of degenerative spondylolisthesis. We were unable to detect differences in radiographic outcomes, complication rates, or patient reported outcomes. Continued efforts to directly compare approaches for specific indications will minimize complications and improve outcomes. Further studies will continue to define indications for lateral versus anterior approach to lumbar spine for degenerative spondylolisthesis.