Effects of a comprehensive brain computed tomography deep learning model on radiologist detection accuracy.

OBJECTIVES: Non-contrast computed tomography of the brain (NCCTB) is commonly used to detect intracranial pathology but is subject to interpretation errors. Machine learning can augment clinical decision-making and improve NCCTB scan interpretation. This retrospective detection accuracy study assessed the performance of radiologists assisted by a deep learning model and compared the standalone performance of the model with that of unassisted radiologists. METHODS: A deep learning model was trained on 212,484 NCCTB scans drawn from a private radiology group in Australia. Scans from inpatient, outpatient, and emergency settings were included. Scan inclusion criteria were age ≥ 18 years and series slice thickness ≤ 1.5 mm. Thirty-two radiologists reviewed 2848 scans with and without the assistance of the deep learning system and rated their confidence in the presence of each finding using a 7-point scale. Differences in AUC and Matthews correlation coefficient (MCC) were calculated using a ground-truth gold standard. RESULTS: The model demonstrated an average area under the receiver operating characteristic curve (AUC) of 0.93 across 144 NCCTB findings and significantly improved radiologist interpretation performance. Assisted and unassisted radiologists demonstrated an average AUC of 0.79 and 0.73 across 22 grouped parent findings and 0.72 and 0.68 across 189 child findings, respectively. When assisted by the model, radiologist AUC was significantly improved for 91 findings (158 findings were non-inferior), and reading time was significantly reduced. CONCLUSIONS: The assistance of a comprehensive deep learning model significantly improved radiologist detection accuracy across a wide range of clinical findings and demonstrated the potential to improve NCCTB interpretation. CLINICAL RELEVANCE STATEMENT: This study evaluated a comprehensive CT brain deep learning model, which performed strongly, improved the performance of radiologists, and reduced interpretation time. The model may reduce errors, improve efficiency, facilitate triage, and better enable the delivery of timely patient care. KEY POINTS: • This study demonstrated that the use of a comprehensive deep learning system assisted radiologists in the detection of a wide range of abnormalities on non-contrast brain computed tomography scans. • The deep learning model demonstrated an average area under the receiver operating characteristic curve of 0.93 across 144 findings and significantly improved radiologist interpretation performance. • The assistance of the comprehensive deep learning model significantly reduced the time required for radiologists to interpret computed tomography scans of the brain.

What is the early fate of adjacent segmental lordosis compensation at L3-4 and L5-S1 following a lateral versus transforaminal lumbar Interbody Fusion at L4-5?

INTRODUCTION: Degenerative spondylolisthesis causes translational and angular malalignment, resulting in a loss of segmental lordosis. This leads to compensatory adjustments in adjacent levels to maintain balance. Lateral lumbar interbody fusion (LLIF) and transforaminal lumbar interbody fusion (TLIF) are common techniques at L4-5. This study compares compensatory changes at adjacent L3-4 and L5-S1 levels six months post LLIF versus TLIF for grade 1 degenerative spondylolisthesis at L4-5. METHODS: A retrospective study included patients undergoing L4-5 LLIF or TLIF with posterior pedicle screw instrumentation (no posterior osteotomy) for grade 1 spondylolisthesis. Pre-op and 6-month post-op radiographs measured segmental lordosis (L3-L4, L4-L5, L5-S1), lumbar lordosis (LL), and pelvic incidence (PI), along with PI-LL mismatch. Multiple regressions were used for hypothesis testing. RESULTS: 113 patients (61 LLIF, 52 TLIF) were studied. TLIF showed less change in L4-5 lordosis (mean = 1.04°, SD = 4.34) compared to LLIF (mean = 4.99°, SD = 5.53) (p = 0.003). L4-5 angle changes didn't correlate with L3-4 changes, and no disparity between LLIF and TLIF was found (all p > 0.16). In LLIF, greater L4-5 lordosis change predicted reduced compensatory L5-S1 lordosis (p = 0.04), while no significant relationship was observed in TLIF patients (p = 0.12). CONCLUSION: LLIF at L4-5 increases lordosis at the operated level, with compensatory decrease at L5-S1 but not L3-4. This reciprocal loss at adjacent L5-S1 may explain inconsistent improvement in lumbar lordosis (PI-LL) post L4-5 fusion.

Machine learning applications to clinical decision support in neurosurgery: an artificial intelligence augmented systematic review.

Machine learning (ML) involves algorithms learning patterns in large, complex datasets to predict and classify. Algorithms include neural networks (NN), logistic regression (LR), and support vector machines (SVM). ML may generate substantial improvements in neurosurgery. This systematic review assessed the current state of neurosurgical ML applications and the performance of algorithms applied. Our systematic search strategy yielded 6866 results, 70 of which met inclusion criteria. Performance statistics analyzed included area under the receiver operating characteristics curve (AUC), accuracy, sensitivity, and specificity. Natural language processing (NLP) was used to model topics across the corpus and to identify keywords within surgical subspecialties. ML applications were heterogeneous. The densest cluster of studies focused on preoperative evaluation, planning, and outcome prediction in spine surgery. The main algorithms applied were NN, LR, and SVM. Input and output features varied widely and were listed to facilitate future research. The accuracy (F(2,19) = 6.56, p < 0.01) and specificity (F(2,16) = 5.57, p < 0.01) of NN, LR, and SVM differed significantly. NN algorithms demonstrated significantly higher accuracy than LR. SVM demonstrated significantly higher specificity than LR. We found no significant difference between NN, LR, and SVM AUC and sensitivity. NLP topic modeling reached maximum coherence at seven topics, which were defined by modeling approach, surgery type, and pathology themes. Keywords captured research foci within surgical domains. ML technology accurately predicts outcomes and facilitates clinical decision-making in neurosurgery. NNs frequently outperformed other algorithms on supervised learning tasks. This study identified gaps in the literature and opportunities for future neurosurgical ML research.

Correction of severe spinopelvic mismatch: decreased blood loss with lateral hyperlordotic interbody grafts as compared with pedicle subtraction osteotomy.

OBJECTIVE Pedicle subtraction osteotomy (PSO) provides extensive correction in patients with fixed sagittal plane imbalance but is associated with high estimated blood loss (EBL). Anterior column realignment (ACR) with lateral graft placement and sectioning of the anterior longitudinal ligament allows restoration of lumbar lordosis (LL). The authors compare peri- and postoperative measures in 2 groups of patients undergoing correction of a sagittal plane imbalance, either through PSO or the use of lateral lumbar fusion and ACR with hyperlordotic (20°-30°) interbody cages, with stabilization through standard posterior instrumentation in all cases. METHODS The authors performed a retrospective chart review of cases involving a lumbar PSO or lateral lumbar interbody fusion and ACR (LLIF-ACR) between 2010 and 2015 at the authors' institution. Patients who had a PSO in the setting of a preexisting fusion that spanned more than 4 levels were excluded. Demographic characteristics, spinopelvic parameters, EBL, operative time, and LOS were analyzed and compared between patients treated with PSO and those treated with LLIF-ACR. RESULTS The PSO group included 14 patients and the LLIF-ACR group included 13 patients. The mean follow-up was 13 months in the LLIF-ACR group and 26 months in the PSO group. The mean EBL was significantly lower in the LLIF-ACR group, measuring approximately 50% of the mean EBL in the PSO group (1466 vs 2910 ml, p < 0.01). Total LL correction was equivalent between the 2 groups (35° in the PSO group, 31° in the LLIF-ACR group, p > 0.05), as was the preoperative PI-LL mismatch (33° in each group, p > 0.05) and the postoperative PI-LL mismatch (< 1° in each group, p = 0.05). The fusion rate as assessed by the need for reoperation due to pseudarthrosis was lower in the LLIF-ACR group but not significantly so (3 revisions in the PSO group due to pseudarthrosis vs 0 in the LLIF-ACR group, p > 0.5). The total operative time and LOS were not significantly different in the 2 groups. CONCLUSIONS This is the first direct comparison of the LLIF-ACR technique with the PSO in adult spinal deformity correction. The study demonstrates that the LLIF-ACR provides equivalent deformity correction with significantly reduced blood loss in patients with a previously unfused spine compared with the PSO. This technique provides a powerful means to avoid PSO in selected patients who require spinal deformity correction.

Successful Implantation of a Ventricular Shunt With Termination in the Iliac Bone in the Adult Patient With Obstructive Hydrocephalus.

BACKGROUND AND IMPORTANCE: With the exception of the 3 classic shunt placement options (ventriculoperitoneal, ventriculopleural, and ventriculoatrial), surgically feasible alternative sites for distal catheter placement remain limited and often require the assistance of an access surgeon. Tubbs et al suggested the possibility of intraosseous cerebrospinal fluid diversion in the ilium, noting that ilium infusion in cadaveric specimens was possible without the development of body edema or fluid overflow. Since this publication, limited case reports have been published on the success of ventriculo-ilium (VI) shunt placement. Here, we describe the technique used for successful VI shunt placement in 2 adult patients. CLINICAL PRESENTATION: Here, we describe 2 patients with differing etiologies of hydrocephalus (obstructive and nonobstructive) and complex medical and surgical problems precluding traditional distal shunt termini. Both patients underwent successful placement of a VI shunt with distal catheter placement into the right iliac crest using a small right-angle connector and small cranial fixation plate to prevent backout of the catheter. DISCUSSION AND CONCLUSION: We report the first demonstration of successful placement of a VI shunt in 2 adult patients with evidence of shunt functionality and improved neurological outcome. We propose that the placement of a VI shunt is an easy and viable option when more traditional shunt methods are not available for use.

Correction of cervical kyphoscoliosis, bisected spinal cord, and vertebral artery to epidural vein fistula in neurofibromatosis type 1.

Neurofibromatosis-1 (NF1) presents complex challenges due to its multisystemic effects, including kyphoscoliosis, dural ectasia, and arteriovenous fistulas (AVF). We present a case of a 31-year-old male with NF1 exhibiting severe cervical kyphoscoliosis, dural ectasia, a bisected cervical cord, and an arteriovenous fistula, highlighting the intricacies of managing such intricate cases. Rapid weakening in the patient's right arm and leg prompted imaging revealing severe cervical kyphotic deformity and a dural fold dividing the spinal cord. Surgical intervention addressed a high-flow arteriovenous fistula involving the right vertebral artery and an epidural vein, necessitating sacrifice of the artery. Posterior fusion and laminectomy were performed, resulting in stable neurological status postoperatively and significant improvement in sensory loss and weakness at three months. This case underscores the importance of a tailored posterior-only approach, involving dural fold release, to allow the spinal cord to relocate to a less tense position, thus demonstrating effective decompression in complex NF1 cases with concurrent kyphotic deformity and vertebral artery AVF.

Transdural retrieval of retropulsed transforaminal lumbar interbody fusion cages.

Transforaminal lumbar interbody fusions (TLIFs) are performed for various lumbar spine pathologies. Posterior migration of an interbody cage is a complication that may result in neurologic injury and require reoperation. Sparse information exists regarding the safety and efficacy of a transdural approach for cage retrieval. We describe a surgical technique, in which centrally retropulsed cages were safely retrieved transdurally. A patient with prior L3-S1 posterior lumbar fusion and L4-S1 TLIFs presented with radiculopathy and weakness in dorsiflexion. Imaging revealed posterior central migration of TLIF cages causing compression of the traversing L5 nerve root. Cages were removed transdurally; the correction was performed with an all-posterior T10-pelvis fusion. Aside from temporary weakness in right-sided dorsiflexion, the patient experienced complete resolution in their radiculopathy and strength returned to its presurgical state by 3 months. The transdural approach for interbody removal can be safely performed and should be a tool in the spine surgeon's armamentarium.

Opiate-reduction protocol for common outpatient spinal procedures: a long-term feasibility study and single-center experience.

OBJECTIVE: The opioid epidemic continues to be at the forefront of public health. As a response to this crisis, many statewide and national medical groups have sought to develop opioid-prescribing guidelines for both acute and chronic pain states. Given the lack of evidence in the neurosurgical landscape, the authors' institution implemented opioid-prescribing guidelines for common outpatient spinal procedures in 2017, subsequently demonstrating a significant reduction in the narcotics prescribed. However, the ability to maintain the results garnered from such guidelines long term has not been described. The objective of this study was to evaluate postoperative opioid utilization at a high-volume quaternary referral center 5 years after the initial implementation of an opioid-reduction protocol for common outpatient spinal procedures. METHODS: From the electronic medical records, authors collected data on the number of tablets and total morphine equivalent dose (MED) prescribed, acute postoperative readmissions for pain concerns, refill requests, and conversion to long-term opiate use in the 5 years following implementation of an opioid-reduction protocol for common outpatient spinal procedures. These procedures, undertaken in opiate-naive patients, included 1- or 2-level anterior cervical discectomy and fusion, 1- or 2-level cervical disc replacement, and 1- or 2-level laminectomy, laminotomy, or foraminotomy (cervical or lumbar). RESULTS: The total quantity of narcotics was reduced by 37.0 tablets per patient after protocol implementation and over the 5-year period thereafter. Generally, patients were discharged with an average of 23.3 tablets, concurrent with the initial goal of 24 tablets, set forth in 2017. These results confirm an ongoing reduction in opiate quantities prescribed and overall morphine equivalent totals at the time of discharge over the course of 5 years after initial protocol implementation. CONCLUSIONS: A standardized discharge protocol for postoperative outpatient spinal procedures can lead to long-term reductions in opioid discharge quantity, without compromising patient safety or increasing the utilization of hospital resources through readmissions, refill requests, or clinic phone calls. This study provides an example of a feasible and effective discharge prescription regimen that may be generalizable to common outpatient neurosurgical procedures with long-term evidence that a small intervention can lead to ongoing reduced quantities of postoperative opioids at the time of discharge.

Is spinopelvic mismatch associated with increased disability at 2 years following short-segment lumbar fusions?

OBJECTIVE: This study aimed to investigate the impact of pelvic incidence (PI) and lumbar lordosis (LL) matching on health-related quality of life (HRQOL) outcomes in patients undergoing one- or two-level lumbar fusions for degenerative pathology. The study also examined changes in alignment and HRQOL over a 24-month follow-up period. METHODS: A retrospective cohort study used data from a multicenter, prospectively collected database. Radiographic parameters were measured preoperatively and at 3-month and 24-month postoperative time points. Patients were categorized as having alignment (PI-LL ≤ 10°) or malalignment (PI-LL > 10°) at all time points. The Oswestry Disability Index scores were collected at the same time points. Statistical analyses assessed differences in HRQOL scores and radiographic parameters between the aligned and malaligned groups. RESULTS: Seventy-six patients were included. Both the aligned and malaligned groups showed improved HRQOL scores after surgery, but patients with proper alignment (PI-LL ≤ 10°) had significantly better HRQOL scores at the 24-month follow-up. Alignment remained stable from 3 months to 24 months postoperatively, with minimal movement between the aligned and malaligned groups. CONCLUSIONS: Proper PI-LL matching in one- and two-level lumbar fusions for degenerative pathology leads to improved HRQOL outcomes at the 24-month follow-up. Patients with maintained proper alignment after surgery experience continued improvement in disability levels. Surgeons should consider longer follow-up for patients who do not achieve proper alignment initially, as 24 months is crucial for assessing the consequences of malalignment in short-segment lumbar fusions.

Implementation of the Modified Brain Injury Guidelines Might Be Feasible and Cost-Effective Even in a Nontrauma Hospital.

INTRODUCTION: The modified Brain Injury Guidelines (mBIG) provide a framework to stratify traumatic brain injury (TBI) patients based on clinical and radiographic factors in level 1 and 2 trauma centers. Approximately 75% of all U.S. hospitals do not carry any trauma designation yet could also benefit from these guidelines. To the best of our knowledge, this is the first report of applying the mBIG protocol in a community hospital without any trauma designation. METHODS: All adult patients with a TBI in a single center from 2020 to 2022 were retrospectively classified into mBIG categories. The primary outcomes included neurological deterioration, progression on computed tomography of the head, and surgical intervention. Additional outcomes included the hospital costs incurred by the mBIG 1 and mBIG 2 groups. RESULTS: Of the 116 included patients, 35 (30%) would have stratified into mBIG 1, 23 (20%) into mBIG 2, and 58 (50%) into mBIG 3. No patient in mBIG 1 had a decline in neurological examination findings or progression on computed tomography of the head or required neurosurgical intervention. Three patients in mBIG 2 had radiographic progression and one required surgical decompression. Two patients in mBIG 3 demonstrated a neurological decline and six had radiographic progression. Of the 21 patients who received surgical intervention, 20 were stratified into mBIG 3. Implementation of the mBIG protocol could have reduced costs by >$250,000 during the 2-year period. CONCLUSIONS: The mBIG protocol can safely stratify patients in a nontrauma hospital. Because nontrauma centers tend to see more patients with minor TBIs, implementation could result in significant cost savings, reduce unnecessary hospital and intensive care unit resources, and reduce transfers to a tertiary institution.

Are Variable Screw Angle Change and Screw-to-Vertebral Body Ratio Associated With Radiographic Subsidence Following Anterior Cervical Discectomy and Fusion?

STUDY DESIGN: Retrospective Cohort. OBJECTIVE: This study aims to assess the easily measurable radiographic landmarks of screw-to-vertebral body ratio and changes in screw angle to identify if they are associated with early subsidence following an Anterior cervical discectomy and fusion (ACDF). METHODS: A retrospective cohort study was conducted on patients undergoing 1-3 level ACDF with allograft or PEEK cages. Preoperative, immediate postoperative, and 6-month postoperative radiographs were analyzed to measure intradiscal height (or distance between 2 vertebral bodies) as an anterior vertebral distance (AVD), middle (MVD), and posterior (PVD), screw angle, screw-to-vertebral body length ratio, and interscrew distance. Multivariate stepwise regression analyses were performed. RESULTS: 92 patients were included (42 single-level, 32 two-level, and 18 3-level ACDFs). In single-level ACDFs, a decrease in the caudal screw angle was associated with a decrease in AVD (=.001) and MVD (P = .03). A decrease in the PVD was associated with a decrease in segmental lordosis (P < .001). For two-level ACDFs, a higher caudal screw-to-body ratio was associated with a lower MVD (P = .01). CONCLUSION: Six months following an ACDF for degenerative pathology, a decrease in the caudal screw angle was associated with an increase in radiographic subsidence at the antero-medial aspect of the disc space albeit largely subclinical. This suggests that the caudal screw angle change may serve as a reliable radiographic marker for early radiographic subsidence. Furthermore, a greater screw-to-vertebral body ratio may be protective against radiographic subsidence in two-level ACDF procedures.

Monthly multidisciplinary complex spine conference: a cost-analysis utilizing time-driven activity-based costing.

PURPOSE: To understand costs and provide an initial framework associated with conference implementation as it pertains to complication prevention. METHODS: Team members' time spent on conference preparation, presentation, and follow-up tasks was recorded and averaged to determine the time required to prepare and present one patient. Using 2022 hourly wage rates based on our urban hospital setting, wage values were calculated for each personnel type and applied to their time spent. The total cost of the conference was annualized and calculated from the time spent in the three phases of the conference multiplied by the wage rate. Published data on complication rates and associated costs before and after conference implementation were used to calculate total cost reduction. RESULTS: With 3 active spine surgeons and 108 patients per year, the total time investment was 104.04 min per patient, costing $21,791 annually. Total RN equivalent value per patient was 5.25 for all three phases. Using a historical model, this multidisciplinary approach for adult spinal deformity reduced complications by 51% at 30 days, resulting in cost savings of $418,518 per year. Thus, the model demonstrates that implementation of this approach resulted in a potential total savings of $396,726/year. CONCLUSION: Implementing a cost-saving tool for managing complex spinal disorders is a responsibility of the spine team, who should lead a multidisciplinary conference. The combination of TDABC and lean methodology can effectively demonstrate the variable costs associated with this multidisciplinary effort and models provide evidence of potential cost-savings when applied to a multidisciplinary adult spinal deformity conference. These findings should encourage clinicians and administrators to allocate resources to improve patient care by reducing complications and costs.

Personalized Medicine in Orthopaedic Surgery: The Case of Spine Surgery.

Personalized medicine has made a tremendous impact on patient care. Although initially, it revolutionized pharmaceutical development and targeted therapies in oncology, it has also made an important impact in orthopaedic surgery. The field of spine surgery highlights the effect of personalized medicine because the improved understanding of spinal pathologies and technological innovations has made personalized medicine a key component of patient care. There is evidence for several of these advancements to support their usage in improving patient care. Proper understanding of normative spinal alignment and surgical planning software has enabled surgeons to predict postoperative alignment accurately. Furthermore, 3D printing technologies have demonstrated the ability to improve pedicle screw placement accuracy compared with free-hand techniques. Patient-specific, precontoured rods have shown improved biomechanical properties, which reduces the risk of postoperative rod fractures. Moreover, approaches such as multidisciplinary evaluations tailored to specific patient needs have demonstrated the ability to decrease complications. Personalized medicine has shown the ability to improve care in all phases of surgical management, and several of these approaches are now readily available to orthopaedic surgeons.

Incidence, etiology and time course of delays to adult spinal deformity surgery: a single-center experience.

PURPOSE: We sought to determine the incidence, origin, and timeframe of delays to adult spinal deformity surgery so that institutions using preoperative multidisciplinary patient assessment teams might better anticipate and address these potential delays. METHODS: Complex spine procedures for treatment of adult spinal deformity from 1/1/18 to 8/31/21 were identified. Procedures for infection, tumor, and urgent/emergent cases were excluded. Operations delayed due to COVID or those that were performed outside of our established perioperative care pathway were also excluded. The electronic health record was used to identify the etiology and timeline of all pre- and peri-operative delays. RESULTS: Of 235 patients scheduled for complex spine surgery, 193 met criteria for inclusion. Of these patients, 35 patients experienced a surgical delay (18.1%) with a total of 41 delays recorded. Reasons for delay include medically unoptimized (25.6%), intraoperative complication (17.9%), patient directed delay (17.9%), patient illness/injury (15.4%), scheduling complication (10.3%), insurance delay/denial (5.1%), and unknown (2.6%). Twenty-four delays experienced by 22 individuals occurred within 7 days of their scheduled surgery date. CONCLUSION: At a single multidisciplinary center, most delays to adult spinal deformity surgery occur before a patient is admitted to the hospital, and for recommendations of additional medical workup/clearance. We suspect that the preoperative protocol might increase pre-admission delays for unoptimized patients, as the protocol is intended to ensure patients receive surgery only when they are medically ready. Further research is needed to determine the economic and system impact of delays related to a preoperative optimization protocol weighed against the reduction in adverse events these protocols can provide.

Clinical Guidelines for the Evaluation and Treatment of Lumbar Disc Herniations: How Accurate is the Internet?

OBJECTIVE: To compare information online regarding lumbar disc herniation (LDH) on commonly searched websites and compare those findings with the evidence-based recommendations listed in the North American Spine Society (NASS) clinical practice guidelines. METHODS: NASS Clinical Practice Guidelines, Internet searches were performed utilizing three common search engines (Google, Bing, Yahoo) and keywords associated with LDH. The top 20 websites from each search were selected. The content regarding diagnosis and treatment of LDH was compared to the NASS clinical practice guidelines. RESULTS: On average, websites mentioned only 59% of recommendations supported by Level I evidence. Websites included an average of 3 recommendations not discussed in the NASS guidelines out of an average of 12 total recommendations. Muscle and sensory testing and physical therapy were the most frequent recommendations, appearing on over 80% of websites. Websites were equally likely to contain recommendations backed by high-quality evidence as recommendations not included in NASS guidelines. CONCLUSIONS: This study demonstrates that websites regarding LDH contain a mix of information, with only a fraction of recommendations aligning with NASS clinical guidelines. Patients who use these websites are presented with unsubstantiated information, conceivably impacting their understanding, expectations and decision-making in physician offices.

What is the fate of the adjacent segmental angles 6 months after single-level L3-4 or L4-5 lateral lumbar interbody fusion?

BACKGROUND CONTEXT: Lateral lumbar interbody fusion (LLIF) is an effective technique for fusion and sagittal alignment correction/maintenance. Studies have investigated the impact on the segmental angle and lumbar lordosis (and pelvic incidence-lumbar lordosis mismatch), however not much is documented regarding the immediate compensation of the adjacent angles. PURPOSE: To evaluate acute adjacent and segmental angle as well as lumbar lordosis changes in patients undergoing a L3-4 or L4-5 LLIF for degenerative pathology. STUDY DESIGN/SETTING: Retrospective cohort study. PATIENT SAMPLE: Patients included in this study were analyzed pre- and post-LLIF performed by one of three fellowship-trained spine surgeons, 6 months following surgery. OUTCOME MEASURES: Patient demographics (including body mass index, diabetes diagnosis, age, and sex) as well as VAS and ODI scores were measured. Lateral lumbar radiograph parameters: lumbar lordosis (LL), segmental lordosis (SL), infra and supra-adjacent segmental angle, and pelvic incidence (PI). METHODS: Multiple regressions were applied for the main hypothesis tests. We examined any interactive effects at each operative level and used the 95% confidence intervals to determine significance: a confidence interval excluding zero indicates a significant effect. RESULTS: We identified 84 patients who underwent a single level LLIF (61 at L4-5, 23 at L3-4). For both the overall sample and at each operative level, the operative segmental angle was significantly more lordotic postop compared to preop (all ps≤.01). Adjacent segmental angles were significantly less lordotic postop compared to pre-op overall (p=.001). For the overall sample, greater lordotic change at the operative segment led to more compensatory reduction of lordosis at the supra-adjacent segment. At L4-5, more lordotic change at the operative segment led to more compensatory lordosis reduction at the infra-adjacent segment. CONCLUSION: The present study demonstrated that LLIF resulted in significant increase in operative level lordosis and a compensatory decrease in supra- and infra-adjacent level lordosis, and subsequently no significant impact on spinopelvic mismatch.

Early Compensatory Segmental Angle Changes at L3-4 and L4-5 Following a L5-S1 Interbody Fusion for a Grade 1 Spondylolisthesis.

STUDY DESIGN: Retrospective study included patients who underwent a L5-S1 ALIF or TLIF with posterior pedicle screw instrumentation for grade 1 spondylolisthesis 2018-2022. OBJECTIVE: To compare early reciprocal changes at the L3-4 and L4-5 adjacent levels six months after anterior (ALIF) or transforaminal (TLIF) lumbar interbody fusion at L5-S1. BACKGROUND: Degenerative and chronic isthmic spondylolistheses often result in decreased segmental lordosis at L5-S1. This can lead to lordotic overcompensation at adjacent levels to maintain spinopelvic balance. However, the fate of adjacent angles following interbody fusion is not well understood. METHODS: Preoperative and 6-month postoperative measurements of segmental lordosis (L3-4, L4-5, and L5-S1), lumbar lordosis, and pelvic incidence were obtained from sagittal standing radiographs. Preliminary t-tests were performed for descriptive purposes, and multiple regression was used for hypothesis testing. RESULTS: Ninety-eight patients met the inclusion criteria (50 ALIF and 48 TLIF). A greater amount of lordosis achieved at L5-S1 was significantly associated with a greater reduction of segmental lordosis at L4-5 (r=-0.65, P<.001) or L3-4 (r=-0.46, P<.001) (Fig. 3A). A greater preoperative PI was associated with a greater reduction of segmental lordosis at L4-L5 (r=-0.42, P<.001) and at L3-L4 (r=-0.44, P<.001). CONCLUSION: At six months following a lumbar interbody fusion at L5-S1, greater compensatory changes with lordosis reduction are observed at the supra-adjacent L4-5 and L3-4 levels in patients achieving greater L5-S1 segmental lordosis. Additionally, preoperative pelvic incidence (PI) played a role in influencing lordotic correction.

Use of Cannulated Reamers to Facilitate Thoracic Diskectomy Using a Minimally Invasive Retropleural Thoracotomy Approach-Surgical Technique.

BACKGROUND: The surgical treatment of symptomatic thoracic disk herniations is technically challenging. In the past decade, a minimally invasive retropleural thoracotomy approach has become more popular to treat this pathology. However, efficient bone removal to safely perform the diskectomy and spinal cord decompression is difficult with this technique because of the small incision size and long working distance in the thoracic cavity and the proximity of the compressed thoracic cord. OBJECTIVE: To describe a novel surgical technique for performing a thoracic diskectomy using a minimally invasive lateral approach using cannulated reamers to facilitate bone removal. METHODS: This technique was used in 7 consecutive patients who presented with thoracic myelopathy from a thoracic disk herniation. First, a standard lateral minimally invasive retropleural approach to the thoracic spine was performed. Partially threaded guide wires were placed in the posterior aspect of the vertebral bodies adjacent to the affected disk space, and sequential cannulated reamers were passed over the guidewires to perform partial corpectomies. The posterior annulus, posterior longitudinal ligament, and herniated disk material were then resected using Penfield dissectors and Kerrison rongeurs to complete the decompression. RESULTS: All 7 patients who underwent thoracic diskectomy using this approach had stable or improved neurologic function postoperatively. There were no complications related to the use of the cannulated reamer technique. CONCLUSION: The use of cannulated reamers provides a simple and efficient method for safe bone removal to facilitate minimally invasive thoracic diskectomy using a lateral approach. This is an easily reproducible technique using commonly available equipment.

Anterior Cervical Corpectomy and Fusion for Degenerative Cervical Spondylotic Myelopathy: Case Presentation With Surgical Technique Demonstration and Review of Literature.

Anterior cervical corpectomy and fusion (ACCF) provides an extensive decompression and provides a large surface area for fusion in patients presenting with cervical spondylotic myelopathy. Unfortunately, this procedure is a more difficult spinal surgery to perform (compared with a traditional anterior cervical discectomy and fusion) and has a higher incidence of overall complications. In literature, ACCF has functional outcomes that seem clinically equivalent to those for multilevel anterior cervical discectomy and fusion, especially when contained to 1 vertebral body level, and in cases, for which both posterior and anterior procedures would be appropriate surgical options, may provide greater long-term clinical benefit than posterior fusion or laminoplasty. In this manuscript, we summarize the indications and outcomes following ACCF for degenerative cervical spondylotic myelopathy. We then describe a case presentation and associated surgical technique with a discussion of complication avoidance with this procedure.