Rhiannon Parker - Academia.edu (original) (raw)

Papers by Rhiannon Parker

Research paper thumbnail of Partial least squares and principal components analysis of wine vintage by high performance liquid chromatography with chemiluminescence detection

Analytica Chimica Acta, Sep 1, 2010

HPLC with acidic potassium permanganate chemiluminescence detection was employed to analyse 17 Ca... more HPLC with acidic potassium permanganate chemiluminescence detection was employed to analyse 17 Cabernet Sauvignon wines across a range of vintages (1971-2003). Partial least squares regression analysis and principal components analysis was used in order to investigate the relationship between wine composition and vintage. Tartaric acid, vanillic acid, catechin, sinapic acid, ethyl gallate, myricetin, procyanadin B and resveratrol were found to be important components in terms of differences between the vintages.

Research paper thumbnail of Profiling of secondary metabolites in blue lupin inoculated with Phytophthora cinnamomi following phosphite treatment

Functional Plant Biology, 2013

In order to discover phytochemicals that are potentially bioactive against Phytophthora cinnamomi... more In order to discover phytochemicals that are potentially bioactive against Phytophthora cinnamomi, (a soil-borne plant pathogen) a metabolite profiling protocol for investigation of metabolic changes in Lupinus angustifolius L. plant roots in response to pathogen challenge has been established. Analysis of the metabolic profiles from healthy and P. cinnamomi-inoculated root tissue with high resolution mass spectrometry and nuclear magnetic resonance spectroscopy confirmed that although susceptible, L. angustifolius upregulated a defence associated genistein and 2′-hydroxygenistein-based isoflavonoid and a soyasapogenol saponin at 12 h post inoculation which increased in concentration at 72 h post inoculation. In contrast to the typical susceptible interaction, the application of a phosphorous-based treatment to L. angustifolius foliage 48 h before P. cinnamomi challenge negated the ability of the pathogen to colonise the root tissue and cause disease. Importantly, although the root profiles of water-treated and phosphite-treated plants post pathogen inoculation contained the same secondary metabolites, concentration variations were observed. Accumulation of secondary metabolites within the P. cinnamomi-inoculated plants confirms that pathogen ingress of the root interstitially occurs in phosphite-treated plants, confirming a direct mode of action against the pathogen upon breaching the root cells.

Research paper thumbnail of Maintenance of Segmental Lordosis and Disc Height in Standalone and Instrumented Extreme Lateral Interbody Fusion (XLIF)

Journal of Spinal Disorders and Techniques, 2014

Prospective single surgeon non-randomized clinical study. To evaluate radiographic and clinical o... more Prospective single surgeon non-randomized clinical study. To evaluate radiographic and clinical outcomes, by fixation type, in extreme lateral interbody fusion (XLIF) patients and provide an algorithm for determining patients suitable for standalone XLIF. XLIF may be supplemented with pedicle screw fixation, however, since stabilizing structures remain intact, it is suggested that standalone XLIF can be used for certain indications. This eliminates the associated morbidity, though subsidence rates may be elevated, potentially minimizing the clinical benefits. A fixation algorithm was developed after evaluation of patient outcomes from the surgeon's first 30 cases. This algorithm was used prospectively for 40 subsequent patients to determine requirement for supplemental fixation. Preoperative, postoperative and 12 month follow-up computed tomography (CT) scans were measured for segmental and global lumbar lordosis and posterior disc height. Clinical outcome measures included back and leg pain (visual analogue scale), Oswestry Disability Index (ODI), and SF-36 physical and mental component scores (PCS and MCS). Preoperatively to 12 month follow-up there were increases in segmental lordosis (7.9° to 9.4, P=0.0497), lumbar lordosis (48.8° to 55.2°, P=0.0328) and disc height (3.7 mm to 5.5 mm, P=0.0018); there were also improvements in back (58.6%) and leg pain (60.0%), ODI (44.4%), PCS (56.7%) and MCS (16.1%) for standalone XLIF. For instrumented XLIF, segmental lordosis (7.6° to 10.5°, P=0.0120) and disc height (3.5 mm to 5.6 mm, P<0.001) increased, whilst lumbar lordosis decreased (51.1° to 45.8°, P=0.2560). Back (49.8%) and leg pain (30.8%), ODI (32.3%), PCS (37.4%) and MCS (2.0%) were all improved. Subsidence occurred in 3 (7.5%) standalone patients. The XLIF treatment fixation algorithm provided a clinical pathway to select suitable patients for standalone XLIF. These patients achieved positive clinical outcomes, satisfactory fusion rates, with sustained correction of lordosis and restoration of disc height.

Research paper thumbnail of Maintenance of Segmental Lordosis and Disc Height in Standalone and Instrumented Extreme Lateral Interbody Fusion (XLIF)

Journal of Spinal Disorders and Techniques, 2014

Prospective single surgeon non-randomized clinical study. To evaluate radiographic and clinical o... more Prospective single surgeon non-randomized clinical study. To evaluate radiographic and clinical outcomes, by fixation type, in extreme lateral interbody fusion (XLIF) patients and provide an algorithm for determining patients suitable for standalone XLIF. XLIF may be supplemented with pedicle screw fixation, however, since stabilizing structures remain intact, it is suggested that standalone XLIF can be used for certain indications. This eliminates the associated morbidity, though subsidence rates may be elevated, potentially minimizing the clinical benefits. A fixation algorithm was developed after evaluation of patient outcomes from the surgeon's first 30 cases. This algorithm was used prospectively for 40 subsequent patients to determine requirement for supplemental fixation. Preoperative, postoperative and 12 month follow-up computed tomography (CT) scans were measured for segmental and global lumbar lordosis and posterior disc height. Clinical outcome measures included back and leg pain (visual analogue scale), Oswestry Disability Index (ODI), and SF-36 physical and mental component scores (PCS and MCS). Preoperatively to 12 month follow-up there were increases in segmental lordosis (7.9° to 9.4, P=0.0497), lumbar lordosis (48.8° to 55.2°, P=0.0328) and disc height (3.7 mm to 5.5 mm, P=0.0018); there were also improvements in back (58.6%) and leg pain (60.0%), ODI (44.4%), PCS (56.7%) and MCS (16.1%) for standalone XLIF. For instrumented XLIF, segmental lordosis (7.6° to 10.5°, P=0.0120) and disc height (3.5 mm to 5.6 mm, P<0.001) increased, whilst lumbar lordosis decreased (51.1° to 45.8°, P=0.2560). Back (49.8%) and leg pain (30.8%), ODI (32.3%), PCS (37.4%) and MCS (2.0%) were all improved. Subsidence occurred in 3 (7.5%) standalone patients. The XLIF treatment fixation algorithm provided a clinical pathway to select suitable patients for standalone XLIF. These patients achieved positive clinical outcomes, satisfactory fusion rates, with sustained correction of lordosis and restoration of disc height.

Research paper thumbnail of Early experience of placing image-guided minimally invasive pedicle screws without K-wires or bone-anchored trackers

Journal of neurosurgery, Apr 1, 2018

umbar pedicle screw-rod fixation for interbody fusion or supplemental posterior fixation traditio... more umbar pedicle screw-rod fixation for interbody fusion or supplemental posterior fixation traditionally uses open anatomical landmarks for screw entry points and pedicle cannulation. The evolution of minimally invasive spine surgery (MISS) has removed these visible anatomical landmarks and is instead reliant on 2D fluoroscopy for pedicle cannulation and Kirchner wire (Kwire) placement. 6,16 K-wires can break, pull out, or advance during pedicle screw insertion and potentially cause neural, vascular, or visceral injury. 8 A "K-wireless" technique using 2D fluoroscopy has been described. 17 The development of intraoperative 3D fluoroscopy and ABBREVIATIONS ALIF = anterior lumbar interbody fusion; LED = light-emitting diode; LLIF = lateral lumbar interbody fusion; MISS = minimally invasive spine surgery; PLIF = posterior lumbar interbody fusion; tEMG = triggered electromyography; TLIF = transforaminal lumbar interbody fusion. ACCOMPANYING EDITORIAL See pp 355-356.

Research paper thumbnail of Subsidence in LLIF

Intervertebral cage settling during bone remodelling is a common occurrence in the normal healing... more Intervertebral cage settling during bone remodelling is a common occurrence in the normal healing process following lumbar interbody fusion (LIF). Subsidence is the progression of this cage settling with endplate collapse; it may lead to a loss of indirect decompression and alignment correction, with a reduced chance of successful fusion and possible reoperation. However, the presence of radiographic subsidence does not always correlate to clinical findings. Subsidence can be related to many factors including bone quality, surgical technique, cage morphology and the use of osteobiologics.

Research paper thumbnail of Clinical Outcome and Fusion Rates after the First 30 Extreme Lateral Interbody Fusions

The Scientific World Journal, 2012

Introduction. The lateral transpsoas approach for lumbar interbody fusion (XLIF) is gaining popul... more Introduction. The lateral transpsoas approach for lumbar interbody fusion (XLIF) is gaining popularity. Studies examining a surgeon's early experience are rare. We aim to report treatment, complication, clinical, and radiographic outcomes in an early series of patients. Methods. Prospective data from the first thirty patients treated with XLIF by a single surgeon was reviewed. Outcome measures included pain, disability, and quality of life assessment. Radiographic assessment of fusion was performed by computed tomography. Results. Average follow-up was 11.5 months, operative time was 60 minutes per level and blood loss was 50 mL. Complications were observed: clinical subsidence, cage breakage upon insertion, new postoperative motor deficit and bowel injury. Approach side-effects were radiographic subsidence and anterior thigh sensory changes. Two patients required reoperation; microforaminotomy and pedicle screw fixation respectively. VAS back and leg pain decreased 63% and 56%, respectively. ODI improved 41.2% with 51.3% and 8.1% improvements in PCS and MCS. Complete fusion (last follow-up) was observed in 85%. Conclusion. The XLIF approach provides superior treatment, clinical outcomes and fusion rates compared to conventional surgical approaches with lowered complication rates. Mentor supervision for early cases and strict adherence to the surgical technique including neuromonitoring is essential.

Research paper thumbnail of Image Guided Percutaneous Pedicle Screws without K-wires or Bone-Anchored Trackers

The Spine Journal, Oct 1, 2017

BACKGROUND CONTEXT: Randomized controlled trials have suggested that bone morphogenetic protein (... more BACKGROUND CONTEXT: Randomized controlled trials have suggested that bone morphogenetic protein (BMP) can increase the likelihood of solid fusion for spine arthrodesis. More recently, BMP has been shown to improve fusion rates in long posterior spine fusions for deformity. The implication of these results is fewer reoperations for pseudarthrosis; however, small cohort sizes looking at fusion rates in lumbar laminectomy and fusion with BMP are inadequate to monitor these relatively rare events. This study follows the inpatient stay administrative data collected for a cohort of thousands of patients who had spine fusion surgery in the state of New York, USA. We sought to examine patients who underwent laminectomy and posterior lumbar fusion for reoperation events with and without the use of BMP. PURPOSE: Determine whether the use of BMP is associated with decreased risk of reoperation among patients who have laminectomy and posterior lumbar fusion.

Research paper thumbnail of Maintenance of Segmental Lordosis and Disk Height in Stand-alone and Instrumented Extreme Lateral Interbody Fusion (XLIF)

Clinical spine surgery, Mar 1, 2017

Study Design: A prospective single-surgeon nonrandomized clinical study. Objective: To evaluate t... more Study Design: A prospective single-surgeon nonrandomized clinical study. Objective: To evaluate the radiographic and clinical outcomes, by fixation type, in extreme lateral interbody fusion (XLIF) patients and provide an algorithm for determining patients suitable for stand-alone XLIF. Summary of Background Data: XLIF may be supplemented with pedicle screw fixation, however, since stabilizing structures remain intact, it is suggested that stand-alone XLIF can be used for certain indications. This eliminates the associated morbidity, though subsidence rates may be elevated, potentially minimizing the clinical benefits. Materials and Methods: A fixation algorithm was developed after evaluation of patient outcomes from the surgeon’s first 30 cases. This algorithm was used prospectively for 40 subsequent patients to determine the requirement for supplemental fixation. Preoperative, postoperative, and 12-month follow-up computed tomography scans were measured for segmental and global lumbar lordosis and posterior disk height. Clinical outcome measures included back and leg pain (visual analogue scale), Oswestry Disability Index (ODI), and SF-36 physical and mental component scores (PCS and MCS). Results: Preoperatively to 12-month follow-up there were increases in segmental lordosis (7.9–9.4 degrees, P=0.0497), lumbar lordosis (48.8–55.2 degrees, P=0.0328), and disk height (3.7–5.5 mm, P=0.0018); there were also improvements in back (58.6%) and leg pain (60.0%), ODI (44.4%), PCS (56.7%), and MCS (16.1%) for stand-alone XLIF. For instrumented XLIF, segmental lordosis (7.6–10.5 degrees, P=0.0120) and disk height (3.5–5.6 mm, P<0.001) increased, while lumbar lordosis decreased (51.1–45.8 degrees, P=0.2560). Back (49.8%) and leg pain (30.8%), ODI (32.3%), PCS (37.4%), and MCS (2.0%) were all improved. Subsidence occurred in 3 (7.5%) stand-alone patients. Conclusions: The XLIF treatment fixation algorithm provided a clinical pathway to select suitable patients for stand-alone XLIF. These patients achieved positive clinical outcomes, satisfactory fusion rates, with sustained correction of lordosis and restoration of disk height.

Research paper thumbnail of Early experience with lateral lumbar total disc replacement: Utility, complications and revision strategies

Journal of Clinical Neuroscience, May 1, 2017

Lumbar total disc replacement (TDR) is an alternative to interbody fusion for the treatment of sy... more Lumbar total disc replacement (TDR) is an alternative to interbody fusion for the treatment of symptomatic degenerative disc disease. Traditionally, lumbar TDR is performed via an anterior retroperitoneal approach with regional risks of vascular and visceral injury. The direct lateral retroperitoneal, transpsoas approach avoids mobilisation of the great vessels and preserves the anterior longitudinal ligament, thereby maintaining physiological limits on motion. This study aimed to (i) report one site's early experience with lateral lumbar TDR and (ii) provide case examples illustrating the utility, complications and revision strategies of the XL-TDR device. Data were collected prospectively on the first 12 consecutive patients treated with XL-TDR. Patient outcomes included pain (VAS), disability (ODI), and quality of life (SF-36 PCS and MCS). Mean follow-up was 27.5 months (range 18-48 months). Patients had significant improvements in back (74%) and leg (50%) pain, ODI (69%), PCS (50%) and MCS (39%) (P < 0.05). Two patients had early prosthesis dislocation due to prosthesis undersizing. The same skin incision was used to retrieve the XL-TDR and perform salvage lateral lumber interbody fusion, with solid fusion by 12 months. Lumbar TDR using the XL-TDR via a lateral transpsoas muscle-splitting approach is a minimally invasive alternative to anterior retroperitoneal exposures for motion preservation. Correct sizing of the XL-TDR and complete contralateral annulectomy with annulus box cutters mitigates the risk of lateral dislocation. Revision surgery for lateral dislocation of the XL-TDR is more straightforward compared to anterior TDR dislocation.

Research paper thumbnail of Clinical results and limitations of indirect decompression in spinal stenosis with laterally implanted interbody cages: results from a prospective cohort study

European Spine Journal, Feb 14, 2015

The lateral approach for anterior interbody fusion allows placement of a large footprint interver... more The lateral approach for anterior interbody fusion allows placement of a large footprint intervertebral spacer to indirectly decompress the neural elements through disc height restoration and resultant soft tissue changes. However, it is not well understood under what circumstances indirect decompression in lateral approach surgery is sufficient. This report aimed to evaluate clinical scenarios where indirect decompression was and was not sufficient in symptom resolution when using lateral interbody fusion. A prospective study was undertaken of 122 consecutive patients treated with lateral interbody fusion without direct decompression. Pre- and postoperative symptomatology was assessed to evaluate the extent of neural decompression following implantation with a lateral polyetheretherketone spacer. Failure to improve or resolve preoperative radicular pain was considered a failure of indirect decompression and indicated these patients for additional posterior decompressive surgery. Unplanned second stage decompression was required in 11 patients. Of these patients, 7/11 early in this series had pathology that was underappreciated including spondylolisthesis from high grade facet arthropathy with instability (3), bony lateral recess stenosis (3) and both spondylolisthesis/stenosis (1). Three patients had iatrogenic leg pain through cage misplacement. There was one failure of indirect decompression that could not be explained through retrospective analysis of the patient&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s record. Indirect decompression clearly has a role in minimizing the amount of surgery that is required. However, it is important to consider the circumstances where this technique may be effective and preoperative considerations that may improve patient selection.

Research paper thumbnail of Anterolateral Fixation in LLIF

Lateral lumbar interbody fusion (LLIF) permits the insertion of a wide footprint interbody cage t... more Lateral lumbar interbody fusion (LLIF) permits the insertion of a wide footprint interbody cage that optimizes cage-endplate interface, restores disc height, and provides indirect neural decompression and correction of sagittal/coronal deformity. The use of supplemental internal fixation in LLIF provides higher fusion rates, facilitates deformity correction and maintains correction until fusion. Importantly, fixation reduces the risk of cage subsidence that can have serious consequences including loss of indirect decompression requiring revision surgery. Factors influencing the need for supplemental lateral or posterior fixation in LLIF include bone density, degree of facet arthropathy, coronal or sagittal imbalance, radiographic or clinical instability, pars defects, spondylolisthesis, cage width, number of proposed levels, presence of an adjacent fusion, intraoperative vertebral endplate injury during cage insertion or endplate preparation, and planned or unplanned ALL rupture. Biomechanical data indicates improved stability of the spinal segment with lateral fixation, posterior fixation such as pedicle screws, facet screws, cortical screws and interspinous clamps, or a combination of both lateral and posterior fixation. However, bilateral pedicle screw-rod fixation remains the gold standard. In LLIF supplementary fixation is indicated to avoid subsidence, add stability, or correct deformity. Instrumentation is recommended in all patients with osteoporosis, radiographic or clinical instability and intraoperative unplanned events such as endplate injury or ALL rupture.

Research paper thumbnail of Indirect Foraminal Decompression Is Independent of Metabolically Active Facet Arthropathy in Extreme Lateral Interbody Fusion

Spine, Oct 1, 2014

Study Design. Retrospective analysis of prospectively collected, nonrandomized radiographical dat... more Study Design. Retrospective analysis of prospectively collected, nonrandomized radiographical data. Objective. To examine the relationship between the presence of preoperative metabolically active facet arthropathy (FA) and the amount of indirect foraminal decompression gained after extreme lateral interbody fusion (XLIF). Summary of Background Data. Although evidence of signifi cant radiographical indirect decompression after XLIF has been shown, the relationship between the extent of indirect decompression and the presence of potentially attenuating, FA is yet to be studied. Methods. A prospective database of consecutive patients undergoing XLIF was retrospectively analyzed. Posterior disc height, foraminal height, and cross-sectional foraminal area were measured on computed tomographic scans obtained preoperatively and 2 days postoperatively. The selected radiographical parameters were examined with respect to the presence of FA based on preoperative computed tomographic and bone scans. Results. Fifty-two consecutive patients underwent 79 levels of XLIF without direct decompression. Average age was 66.4 years and 34 (65.4%) were females. Surgery resulted in signifi cant increases in posterior disc height 3.0 to 5.7 mm (89.0% increase), P < 0.0001; foraminal height 1.4 to 1.7 cm (38.0% increase), P < 0.0001; and foraminal area 1.1 to 1.4 cm 2 (45.1% increase), P < 0.0001. These increases were independent of the presence of metabolically active arthropathy.

Research paper thumbnail of Assessment and classification of subsidence after lateral interbody fusion using serial computed tomography

Journal of neurosurgery, Nov 1, 2015

Assessment and classification of subsidence after lateral interbody fusion using serial computed ... more Assessment and classification of subsidence after lateral interbody fusion using serial computed tomography gregory m. malham, mbchb, 1 rhiannon m. parker, phd, 2 carl m. blecher, mbbS, ddu, 3 and Kevin a. Seex, mbchb 4

Research paper thumbnail of Treatment of symptomatic thoracic disc herniations with lateral interbody fusion

PubMed, Dec 1, 2015

Background: Symptomatic thoracic herniated discs have historically been treated using open exposu... more Background: Symptomatic thoracic herniated discs have historically been treated using open exposures (i.e., thoracotomy), posing a clinical challenge given the approach related morbidity. Lateral interbody fusion (LIF) is one modern minimally disruptive alternative to thoracotomy. The direct lateral technique for lumbar pathologies has seen a sharp increase in procedural numbers; however application of this technique in thoracic pathologies has not been widely reported. Methods: This study presents the results of three cases where LIF was used to treat symptomatic thoracic disc herniations. Indications for surgery included thoracic myelopathy, radiculopathy and discogenic pain. Patients were treated with LIF, without supplemental internal fixation, and followed for 24 months postoperatively. Results: Average length of hospital stay was 5 days. One patient experienced mild persistent neuropathic thoracic pain, which was managed medically. At 3 months postoperative all patients had returned to work and by 12 months all patients were fused. From preoperative to 24-month follow-up there were mean improvements of 83.3% in visual analogue scale (VAS), 75.3% in Oswestry Disability Index (ODI), and 79.2% and 17.4% in SF-36 physical (PCS) and mental component scores (MCS), respectively. Conclusions: LIF is a viable minimally invasive alternative to conventional approaches in treating symptomatic thoracic pathology without an access surgeon, rib resection, or lung deflation.

Research paper thumbnail of Image Guided Percutaneous Pedicle Screws without K-wires or Bone-Anchored Trackers

The Spine Journal, 2017

BACKGROUND CONTEXT: Randomized controlled trials have suggested that bone morphogenetic protein (... more BACKGROUND CONTEXT: Randomized controlled trials have suggested that bone morphogenetic protein (BMP) can increase the likelihood of solid fusion for spine arthrodesis. More recently, BMP has been shown to improve fusion rates in long posterior spine fusions for deformity. The implication of these results is fewer reoperations for pseudarthrosis; however, small cohort sizes looking at fusion rates in lumbar laminectomy and fusion with BMP are inadequate to monitor these relatively rare events. This study follows the inpatient stay administrative data collected for a cohort of thousands of patients who had spine fusion surgery in the state of New York, USA. We sought to examine patients who underwent laminectomy and posterior lumbar fusion for reoperation events with and without the use of BMP. PURPOSE: Determine whether the use of BMP is associated with decreased risk of reoperation among patients who have laminectomy and posterior lumbar fusion.

Research paper thumbnail of Early experience of placing image-guided minimally invasive pedicle screws without K-wires or bone-anchored trackers

Journal of Neurosurgery: Spine, 2018

OBJECTIVEImage guidance for spine surgery has been reported to improve the accuracy of pedicle sc... more OBJECTIVEImage guidance for spine surgery has been reported to improve the accuracy of pedicle screw placement and reduce revision rates and radiation exposure. Current navigation and robot-assisted techniques for percutaneous screws rely on bone-anchored trackers and Kirchner wires (K-wires). There is a paucity of published data regarding the placement of image-guided percutaneous screws without K-wires. A new skin-adhesive stereotactic patient tracker (SpineMask) eliminates both an invasive bone-anchored tracker and K-wires for pedicle screw placement. This study reports the authors’ early experience with the use of SpineMask for “K-wireless” placement of minimally invasive pedicle screws and makes recommendations for its potential applications in lumbar fusion.METHODSForty-five consecutive patients (involving 204 screws inserted) underwent K-wireless lumbar pedicle screw fixation with SpineMask and intraoperative neuromonitoring. Screws were inserted by percutaneous stab or Wilts...

Research paper thumbnail of Assessment and classification of subsidence after lateral interbody fusion using serial computed tomography

Journal of Neurosurgery: Spine, 2015

OBJECT Intervertebral cage settling during bone remodeling after lumbar lateral interbody fusion ... more OBJECT Intervertebral cage settling during bone remodeling after lumbar lateral interbody fusion (LIF) is a common occurrence during the normal healing process. Progression of this settling with endplate collapse is defined as subsidence. The purposes of this study were to 1) assess the rate of subsidence after minimally invasive (MIS) LIF by CT, 2) distinguish between early cage subsidence (ECS) and delayed cage subsidence (DCS), 3) propose a descriptive method for classifying the types of subsidence, and 4) discuss techniques for mitigating the risk of subsidence after MIS LIF. METHODS A total of 128 consecutive patients (with 178 treated levels in total) underwent MIS LIF performed by a single surgeon. The subsidence was deemed to be ECS if it was evident on postoperative Day 2 CT images and was therefore the result of an intraoperative vertebral endplate injury and deemed DCS if it was detected on subsequent CT scans (≥ 6 months postoperatively). Endplate breaches were categoriz...

Research paper thumbnail of Brief intraoperative heparinization and blood loss in anterior lumbar spine surgery

Journal of Neurosurgery: Spine, 2015

OBJECT The anterior approach to the lumbar spine may be associated with iliac artery thrombosis. ... more OBJECT The anterior approach to the lumbar spine may be associated with iliac artery thrombosis. Intraoperative heparin can be administered to prevent thrombosis; however, there is a concern that this will increase the procedural blood loss. The aim of this study was to examine whether intraoperative heparin can be administered without increasing blood loss in anterior lumbar spine surgery. METHODS A prospective study of consecutive anterior approaches for lumbar spine surgery was performed between January 2009 and June 2014 by a single vascular surgeon and a single spine surgeon. Patients underwent an anterior lumbar interbody fusion (ALIF) at L4–5 and/or L5–S1, a total disc replacement (TDR) at L4–5 and/or L5–S1, or a hybrid procedure with a TDR at L4–5 and an ALIF at L5–S1. Heparin was administered intravenously when arterial flow to the lower limbs was interrupted during the procedure. Heparin was usually reversed on removal of the causative retraction. RESULTS The cohort consis...

Research paper thumbnail of Indirect Foraminal Decompression Is Independent of Metabolically Active Facet Arthropathy in Extreme Lateral Interbody Fusion

Spine, 2014

Study Design. Retrospective analysis of prospectively collected, nonrandomized radiographical dat... more Study Design. Retrospective analysis of prospectively collected, nonrandomized radiographical data. Objective. To examine the relationship between the presence of preoperative metabolically active facet arthropathy (FA) and the amount of indirect foraminal decompression gained after extreme lateral interbody fusion (XLIF). Summary of Background Data. Although evidence of signifi cant radiographical indirect decompression after XLIF has been shown, the relationship between the extent of indirect decompression and the presence of potentially attenuating, FA is yet to be studied. Methods. A prospective database of consecutive patients undergoing XLIF was retrospectively analyzed. Posterior disc height, foraminal height, and cross-sectional foraminal area were measured on computed tomographic scans obtained preoperatively and 2 days postoperatively. The selected radiographical parameters were examined with respect to the presence of FA based on preoperative computed tomographic and bone scans. Results. Fifty-two consecutive patients underwent 79 levels of XLIF without direct decompression. Average age was 66.4 years and 34 (65.4%) were females. Surgery resulted in signifi cant increases in posterior disc height 3.0 to 5.7 mm (89.0% increase), P < 0.0001; foraminal height 1.4 to 1.7 cm (38.0% increase), P < 0.0001; and foraminal area 1.1 to 1.4 cm 2 (45.1% increase), P < 0.0001. These increases were independent of the presence of metabolically active arthropathy.

Research paper thumbnail of Partial least squares and principal components analysis of wine vintage by high performance liquid chromatography with chemiluminescence detection

Analytica Chimica Acta, Sep 1, 2010

HPLC with acidic potassium permanganate chemiluminescence detection was employed to analyse 17 Ca... more HPLC with acidic potassium permanganate chemiluminescence detection was employed to analyse 17 Cabernet Sauvignon wines across a range of vintages (1971-2003). Partial least squares regression analysis and principal components analysis was used in order to investigate the relationship between wine composition and vintage. Tartaric acid, vanillic acid, catechin, sinapic acid, ethyl gallate, myricetin, procyanadin B and resveratrol were found to be important components in terms of differences between the vintages.

Research paper thumbnail of Profiling of secondary metabolites in blue lupin inoculated with Phytophthora cinnamomi following phosphite treatment

Functional Plant Biology, 2013

In order to discover phytochemicals that are potentially bioactive against Phytophthora cinnamomi... more In order to discover phytochemicals that are potentially bioactive against Phytophthora cinnamomi, (a soil-borne plant pathogen) a metabolite profiling protocol for investigation of metabolic changes in Lupinus angustifolius L. plant roots in response to pathogen challenge has been established. Analysis of the metabolic profiles from healthy and P. cinnamomi-inoculated root tissue with high resolution mass spectrometry and nuclear magnetic resonance spectroscopy confirmed that although susceptible, L. angustifolius upregulated a defence associated genistein and 2′-hydroxygenistein-based isoflavonoid and a soyasapogenol saponin at 12 h post inoculation which increased in concentration at 72 h post inoculation. In contrast to the typical susceptible interaction, the application of a phosphorous-based treatment to L. angustifolius foliage 48 h before P. cinnamomi challenge negated the ability of the pathogen to colonise the root tissue and cause disease. Importantly, although the root profiles of water-treated and phosphite-treated plants post pathogen inoculation contained the same secondary metabolites, concentration variations were observed. Accumulation of secondary metabolites within the P. cinnamomi-inoculated plants confirms that pathogen ingress of the root interstitially occurs in phosphite-treated plants, confirming a direct mode of action against the pathogen upon breaching the root cells.

Research paper thumbnail of Maintenance of Segmental Lordosis and Disc Height in Standalone and Instrumented Extreme Lateral Interbody Fusion (XLIF)

Journal of Spinal Disorders and Techniques, 2014

Prospective single surgeon non-randomized clinical study. To evaluate radiographic and clinical o... more Prospective single surgeon non-randomized clinical study. To evaluate radiographic and clinical outcomes, by fixation type, in extreme lateral interbody fusion (XLIF) patients and provide an algorithm for determining patients suitable for standalone XLIF. XLIF may be supplemented with pedicle screw fixation, however, since stabilizing structures remain intact, it is suggested that standalone XLIF can be used for certain indications. This eliminates the associated morbidity, though subsidence rates may be elevated, potentially minimizing the clinical benefits. A fixation algorithm was developed after evaluation of patient outcomes from the surgeon&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s first 30 cases. This algorithm was used prospectively for 40 subsequent patients to determine requirement for supplemental fixation. Preoperative, postoperative and 12 month follow-up computed tomography (CT) scans were measured for segmental and global lumbar lordosis and posterior disc height. Clinical outcome measures included back and leg pain (visual analogue scale), Oswestry Disability Index (ODI), and SF-36 physical and mental component scores (PCS and MCS). Preoperatively to 12 month follow-up there were increases in segmental lordosis (7.9° to 9.4, P=0.0497), lumbar lordosis (48.8° to 55.2°, P=0.0328) and disc height (3.7 mm to 5.5 mm, P=0.0018); there were also improvements in back (58.6%) and leg pain (60.0%), ODI (44.4%), PCS (56.7%) and MCS (16.1%) for standalone XLIF. For instrumented XLIF, segmental lordosis (7.6° to 10.5°, P=0.0120) and disc height (3.5 mm to 5.6 mm, P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.001) increased, whilst lumbar lordosis decreased (51.1° to 45.8°, P=0.2560). Back (49.8%) and leg pain (30.8%), ODI (32.3%), PCS (37.4%) and MCS (2.0%) were all improved. Subsidence occurred in 3 (7.5%) standalone patients. The XLIF treatment fixation algorithm provided a clinical pathway to select suitable patients for standalone XLIF. These patients achieved positive clinical outcomes, satisfactory fusion rates, with sustained correction of lordosis and restoration of disc height.

Research paper thumbnail of Maintenance of Segmental Lordosis and Disc Height in Standalone and Instrumented Extreme Lateral Interbody Fusion (XLIF)

Journal of Spinal Disorders and Techniques, 2014

Prospective single surgeon non-randomized clinical study. To evaluate radiographic and clinical o... more Prospective single surgeon non-randomized clinical study. To evaluate radiographic and clinical outcomes, by fixation type, in extreme lateral interbody fusion (XLIF) patients and provide an algorithm for determining patients suitable for standalone XLIF. XLIF may be supplemented with pedicle screw fixation, however, since stabilizing structures remain intact, it is suggested that standalone XLIF can be used for certain indications. This eliminates the associated morbidity, though subsidence rates may be elevated, potentially minimizing the clinical benefits. A fixation algorithm was developed after evaluation of patient outcomes from the surgeon&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s first 30 cases. This algorithm was used prospectively for 40 subsequent patients to determine requirement for supplemental fixation. Preoperative, postoperative and 12 month follow-up computed tomography (CT) scans were measured for segmental and global lumbar lordosis and posterior disc height. Clinical outcome measures included back and leg pain (visual analogue scale), Oswestry Disability Index (ODI), and SF-36 physical and mental component scores (PCS and MCS). Preoperatively to 12 month follow-up there were increases in segmental lordosis (7.9° to 9.4, P=0.0497), lumbar lordosis (48.8° to 55.2°, P=0.0328) and disc height (3.7 mm to 5.5 mm, P=0.0018); there were also improvements in back (58.6%) and leg pain (60.0%), ODI (44.4%), PCS (56.7%) and MCS (16.1%) for standalone XLIF. For instrumented XLIF, segmental lordosis (7.6° to 10.5°, P=0.0120) and disc height (3.5 mm to 5.6 mm, P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.001) increased, whilst lumbar lordosis decreased (51.1° to 45.8°, P=0.2560). Back (49.8%) and leg pain (30.8%), ODI (32.3%), PCS (37.4%) and MCS (2.0%) were all improved. Subsidence occurred in 3 (7.5%) standalone patients. The XLIF treatment fixation algorithm provided a clinical pathway to select suitable patients for standalone XLIF. These patients achieved positive clinical outcomes, satisfactory fusion rates, with sustained correction of lordosis and restoration of disc height.

Research paper thumbnail of Early experience of placing image-guided minimally invasive pedicle screws without K-wires or bone-anchored trackers

Journal of neurosurgery, Apr 1, 2018

umbar pedicle screw-rod fixation for interbody fusion or supplemental posterior fixation traditio... more umbar pedicle screw-rod fixation for interbody fusion or supplemental posterior fixation traditionally uses open anatomical landmarks for screw entry points and pedicle cannulation. The evolution of minimally invasive spine surgery (MISS) has removed these visible anatomical landmarks and is instead reliant on 2D fluoroscopy for pedicle cannulation and Kirchner wire (Kwire) placement. 6,16 K-wires can break, pull out, or advance during pedicle screw insertion and potentially cause neural, vascular, or visceral injury. 8 A "K-wireless" technique using 2D fluoroscopy has been described. 17 The development of intraoperative 3D fluoroscopy and ABBREVIATIONS ALIF = anterior lumbar interbody fusion; LED = light-emitting diode; LLIF = lateral lumbar interbody fusion; MISS = minimally invasive spine surgery; PLIF = posterior lumbar interbody fusion; tEMG = triggered electromyography; TLIF = transforaminal lumbar interbody fusion. ACCOMPANYING EDITORIAL See pp 355-356.

Research paper thumbnail of Subsidence in LLIF

Intervertebral cage settling during bone remodelling is a common occurrence in the normal healing... more Intervertebral cage settling during bone remodelling is a common occurrence in the normal healing process following lumbar interbody fusion (LIF). Subsidence is the progression of this cage settling with endplate collapse; it may lead to a loss of indirect decompression and alignment correction, with a reduced chance of successful fusion and possible reoperation. However, the presence of radiographic subsidence does not always correlate to clinical findings. Subsidence can be related to many factors including bone quality, surgical technique, cage morphology and the use of osteobiologics.

Research paper thumbnail of Clinical Outcome and Fusion Rates after the First 30 Extreme Lateral Interbody Fusions

The Scientific World Journal, 2012

Introduction. The lateral transpsoas approach for lumbar interbody fusion (XLIF) is gaining popul... more Introduction. The lateral transpsoas approach for lumbar interbody fusion (XLIF) is gaining popularity. Studies examining a surgeon's early experience are rare. We aim to report treatment, complication, clinical, and radiographic outcomes in an early series of patients. Methods. Prospective data from the first thirty patients treated with XLIF by a single surgeon was reviewed. Outcome measures included pain, disability, and quality of life assessment. Radiographic assessment of fusion was performed by computed tomography. Results. Average follow-up was 11.5 months, operative time was 60 minutes per level and blood loss was 50 mL. Complications were observed: clinical subsidence, cage breakage upon insertion, new postoperative motor deficit and bowel injury. Approach side-effects were radiographic subsidence and anterior thigh sensory changes. Two patients required reoperation; microforaminotomy and pedicle screw fixation respectively. VAS back and leg pain decreased 63% and 56%, respectively. ODI improved 41.2% with 51.3% and 8.1% improvements in PCS and MCS. Complete fusion (last follow-up) was observed in 85%. Conclusion. The XLIF approach provides superior treatment, clinical outcomes and fusion rates compared to conventional surgical approaches with lowered complication rates. Mentor supervision for early cases and strict adherence to the surgical technique including neuromonitoring is essential.

Research paper thumbnail of Image Guided Percutaneous Pedicle Screws without K-wires or Bone-Anchored Trackers

The Spine Journal, Oct 1, 2017

BACKGROUND CONTEXT: Randomized controlled trials have suggested that bone morphogenetic protein (... more BACKGROUND CONTEXT: Randomized controlled trials have suggested that bone morphogenetic protein (BMP) can increase the likelihood of solid fusion for spine arthrodesis. More recently, BMP has been shown to improve fusion rates in long posterior spine fusions for deformity. The implication of these results is fewer reoperations for pseudarthrosis; however, small cohort sizes looking at fusion rates in lumbar laminectomy and fusion with BMP are inadequate to monitor these relatively rare events. This study follows the inpatient stay administrative data collected for a cohort of thousands of patients who had spine fusion surgery in the state of New York, USA. We sought to examine patients who underwent laminectomy and posterior lumbar fusion for reoperation events with and without the use of BMP. PURPOSE: Determine whether the use of BMP is associated with decreased risk of reoperation among patients who have laminectomy and posterior lumbar fusion.

Research paper thumbnail of Maintenance of Segmental Lordosis and Disk Height in Stand-alone and Instrumented Extreme Lateral Interbody Fusion (XLIF)

Clinical spine surgery, Mar 1, 2017

Study Design: A prospective single-surgeon nonrandomized clinical study. Objective: To evaluate t... more Study Design: A prospective single-surgeon nonrandomized clinical study. Objective: To evaluate the radiographic and clinical outcomes, by fixation type, in extreme lateral interbody fusion (XLIF) patients and provide an algorithm for determining patients suitable for stand-alone XLIF. Summary of Background Data: XLIF may be supplemented with pedicle screw fixation, however, since stabilizing structures remain intact, it is suggested that stand-alone XLIF can be used for certain indications. This eliminates the associated morbidity, though subsidence rates may be elevated, potentially minimizing the clinical benefits. Materials and Methods: A fixation algorithm was developed after evaluation of patient outcomes from the surgeon’s first 30 cases. This algorithm was used prospectively for 40 subsequent patients to determine the requirement for supplemental fixation. Preoperative, postoperative, and 12-month follow-up computed tomography scans were measured for segmental and global lumbar lordosis and posterior disk height. Clinical outcome measures included back and leg pain (visual analogue scale), Oswestry Disability Index (ODI), and SF-36 physical and mental component scores (PCS and MCS). Results: Preoperatively to 12-month follow-up there were increases in segmental lordosis (7.9–9.4 degrees, P=0.0497), lumbar lordosis (48.8–55.2 degrees, P=0.0328), and disk height (3.7–5.5 mm, P=0.0018); there were also improvements in back (58.6%) and leg pain (60.0%), ODI (44.4%), PCS (56.7%), and MCS (16.1%) for stand-alone XLIF. For instrumented XLIF, segmental lordosis (7.6–10.5 degrees, P=0.0120) and disk height (3.5–5.6 mm, P&lt;0.001) increased, while lumbar lordosis decreased (51.1–45.8 degrees, P=0.2560). Back (49.8%) and leg pain (30.8%), ODI (32.3%), PCS (37.4%), and MCS (2.0%) were all improved. Subsidence occurred in 3 (7.5%) stand-alone patients. Conclusions: The XLIF treatment fixation algorithm provided a clinical pathway to select suitable patients for stand-alone XLIF. These patients achieved positive clinical outcomes, satisfactory fusion rates, with sustained correction of lordosis and restoration of disk height.

Research paper thumbnail of Early experience with lateral lumbar total disc replacement: Utility, complications and revision strategies

Journal of Clinical Neuroscience, May 1, 2017

Lumbar total disc replacement (TDR) is an alternative to interbody fusion for the treatment of sy... more Lumbar total disc replacement (TDR) is an alternative to interbody fusion for the treatment of symptomatic degenerative disc disease. Traditionally, lumbar TDR is performed via an anterior retroperitoneal approach with regional risks of vascular and visceral injury. The direct lateral retroperitoneal, transpsoas approach avoids mobilisation of the great vessels and preserves the anterior longitudinal ligament, thereby maintaining physiological limits on motion. This study aimed to (i) report one site's early experience with lateral lumbar TDR and (ii) provide case examples illustrating the utility, complications and revision strategies of the XL-TDR device. Data were collected prospectively on the first 12 consecutive patients treated with XL-TDR. Patient outcomes included pain (VAS), disability (ODI), and quality of life (SF-36 PCS and MCS). Mean follow-up was 27.5 months (range 18-48 months). Patients had significant improvements in back (74%) and leg (50%) pain, ODI (69%), PCS (50%) and MCS (39%) (P < 0.05). Two patients had early prosthesis dislocation due to prosthesis undersizing. The same skin incision was used to retrieve the XL-TDR and perform salvage lateral lumber interbody fusion, with solid fusion by 12 months. Lumbar TDR using the XL-TDR via a lateral transpsoas muscle-splitting approach is a minimally invasive alternative to anterior retroperitoneal exposures for motion preservation. Correct sizing of the XL-TDR and complete contralateral annulectomy with annulus box cutters mitigates the risk of lateral dislocation. Revision surgery for lateral dislocation of the XL-TDR is more straightforward compared to anterior TDR dislocation.

Research paper thumbnail of Clinical results and limitations of indirect decompression in spinal stenosis with laterally implanted interbody cages: results from a prospective cohort study

European Spine Journal, Feb 14, 2015

The lateral approach for anterior interbody fusion allows placement of a large footprint interver... more The lateral approach for anterior interbody fusion allows placement of a large footprint intervertebral spacer to indirectly decompress the neural elements through disc height restoration and resultant soft tissue changes. However, it is not well understood under what circumstances indirect decompression in lateral approach surgery is sufficient. This report aimed to evaluate clinical scenarios where indirect decompression was and was not sufficient in symptom resolution when using lateral interbody fusion. A prospective study was undertaken of 122 consecutive patients treated with lateral interbody fusion without direct decompression. Pre- and postoperative symptomatology was assessed to evaluate the extent of neural decompression following implantation with a lateral polyetheretherketone spacer. Failure to improve or resolve preoperative radicular pain was considered a failure of indirect decompression and indicated these patients for additional posterior decompressive surgery. Unplanned second stage decompression was required in 11 patients. Of these patients, 7/11 early in this series had pathology that was underappreciated including spondylolisthesis from high grade facet arthropathy with instability (3), bony lateral recess stenosis (3) and both spondylolisthesis/stenosis (1). Three patients had iatrogenic leg pain through cage misplacement. There was one failure of indirect decompression that could not be explained through retrospective analysis of the patient&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s record. Indirect decompression clearly has a role in minimizing the amount of surgery that is required. However, it is important to consider the circumstances where this technique may be effective and preoperative considerations that may improve patient selection.

Research paper thumbnail of Anterolateral Fixation in LLIF

Lateral lumbar interbody fusion (LLIF) permits the insertion of a wide footprint interbody cage t... more Lateral lumbar interbody fusion (LLIF) permits the insertion of a wide footprint interbody cage that optimizes cage-endplate interface, restores disc height, and provides indirect neural decompression and correction of sagittal/coronal deformity. The use of supplemental internal fixation in LLIF provides higher fusion rates, facilitates deformity correction and maintains correction until fusion. Importantly, fixation reduces the risk of cage subsidence that can have serious consequences including loss of indirect decompression requiring revision surgery. Factors influencing the need for supplemental lateral or posterior fixation in LLIF include bone density, degree of facet arthropathy, coronal or sagittal imbalance, radiographic or clinical instability, pars defects, spondylolisthesis, cage width, number of proposed levels, presence of an adjacent fusion, intraoperative vertebral endplate injury during cage insertion or endplate preparation, and planned or unplanned ALL rupture. Biomechanical data indicates improved stability of the spinal segment with lateral fixation, posterior fixation such as pedicle screws, facet screws, cortical screws and interspinous clamps, or a combination of both lateral and posterior fixation. However, bilateral pedicle screw-rod fixation remains the gold standard. In LLIF supplementary fixation is indicated to avoid subsidence, add stability, or correct deformity. Instrumentation is recommended in all patients with osteoporosis, radiographic or clinical instability and intraoperative unplanned events such as endplate injury or ALL rupture.

Research paper thumbnail of Indirect Foraminal Decompression Is Independent of Metabolically Active Facet Arthropathy in Extreme Lateral Interbody Fusion

Spine, Oct 1, 2014

Study Design. Retrospective analysis of prospectively collected, nonrandomized radiographical dat... more Study Design. Retrospective analysis of prospectively collected, nonrandomized radiographical data. Objective. To examine the relationship between the presence of preoperative metabolically active facet arthropathy (FA) and the amount of indirect foraminal decompression gained after extreme lateral interbody fusion (XLIF). Summary of Background Data. Although evidence of signifi cant radiographical indirect decompression after XLIF has been shown, the relationship between the extent of indirect decompression and the presence of potentially attenuating, FA is yet to be studied. Methods. A prospective database of consecutive patients undergoing XLIF was retrospectively analyzed. Posterior disc height, foraminal height, and cross-sectional foraminal area were measured on computed tomographic scans obtained preoperatively and 2 days postoperatively. The selected radiographical parameters were examined with respect to the presence of FA based on preoperative computed tomographic and bone scans. Results. Fifty-two consecutive patients underwent 79 levels of XLIF without direct decompression. Average age was 66.4 years and 34 (65.4%) were females. Surgery resulted in signifi cant increases in posterior disc height 3.0 to 5.7 mm (89.0% increase), P < 0.0001; foraminal height 1.4 to 1.7 cm (38.0% increase), P < 0.0001; and foraminal area 1.1 to 1.4 cm 2 (45.1% increase), P < 0.0001. These increases were independent of the presence of metabolically active arthropathy.

Research paper thumbnail of Assessment and classification of subsidence after lateral interbody fusion using serial computed tomography

Journal of neurosurgery, Nov 1, 2015

Assessment and classification of subsidence after lateral interbody fusion using serial computed ... more Assessment and classification of subsidence after lateral interbody fusion using serial computed tomography gregory m. malham, mbchb, 1 rhiannon m. parker, phd, 2 carl m. blecher, mbbS, ddu, 3 and Kevin a. Seex, mbchb 4

Research paper thumbnail of Treatment of symptomatic thoracic disc herniations with lateral interbody fusion

PubMed, Dec 1, 2015

Background: Symptomatic thoracic herniated discs have historically been treated using open exposu... more Background: Symptomatic thoracic herniated discs have historically been treated using open exposures (i.e., thoracotomy), posing a clinical challenge given the approach related morbidity. Lateral interbody fusion (LIF) is one modern minimally disruptive alternative to thoracotomy. The direct lateral technique for lumbar pathologies has seen a sharp increase in procedural numbers; however application of this technique in thoracic pathologies has not been widely reported. Methods: This study presents the results of three cases where LIF was used to treat symptomatic thoracic disc herniations. Indications for surgery included thoracic myelopathy, radiculopathy and discogenic pain. Patients were treated with LIF, without supplemental internal fixation, and followed for 24 months postoperatively. Results: Average length of hospital stay was 5 days. One patient experienced mild persistent neuropathic thoracic pain, which was managed medically. At 3 months postoperative all patients had returned to work and by 12 months all patients were fused. From preoperative to 24-month follow-up there were mean improvements of 83.3% in visual analogue scale (VAS), 75.3% in Oswestry Disability Index (ODI), and 79.2% and 17.4% in SF-36 physical (PCS) and mental component scores (MCS), respectively. Conclusions: LIF is a viable minimally invasive alternative to conventional approaches in treating symptomatic thoracic pathology without an access surgeon, rib resection, or lung deflation.

Research paper thumbnail of Image Guided Percutaneous Pedicle Screws without K-wires or Bone-Anchored Trackers

The Spine Journal, 2017

BACKGROUND CONTEXT: Randomized controlled trials have suggested that bone morphogenetic protein (... more BACKGROUND CONTEXT: Randomized controlled trials have suggested that bone morphogenetic protein (BMP) can increase the likelihood of solid fusion for spine arthrodesis. More recently, BMP has been shown to improve fusion rates in long posterior spine fusions for deformity. The implication of these results is fewer reoperations for pseudarthrosis; however, small cohort sizes looking at fusion rates in lumbar laminectomy and fusion with BMP are inadequate to monitor these relatively rare events. This study follows the inpatient stay administrative data collected for a cohort of thousands of patients who had spine fusion surgery in the state of New York, USA. We sought to examine patients who underwent laminectomy and posterior lumbar fusion for reoperation events with and without the use of BMP. PURPOSE: Determine whether the use of BMP is associated with decreased risk of reoperation among patients who have laminectomy and posterior lumbar fusion.

Research paper thumbnail of Early experience of placing image-guided minimally invasive pedicle screws without K-wires or bone-anchored trackers

Journal of Neurosurgery: Spine, 2018

OBJECTIVEImage guidance for spine surgery has been reported to improve the accuracy of pedicle sc... more OBJECTIVEImage guidance for spine surgery has been reported to improve the accuracy of pedicle screw placement and reduce revision rates and radiation exposure. Current navigation and robot-assisted techniques for percutaneous screws rely on bone-anchored trackers and Kirchner wires (K-wires). There is a paucity of published data regarding the placement of image-guided percutaneous screws without K-wires. A new skin-adhesive stereotactic patient tracker (SpineMask) eliminates both an invasive bone-anchored tracker and K-wires for pedicle screw placement. This study reports the authors’ early experience with the use of SpineMask for “K-wireless” placement of minimally invasive pedicle screws and makes recommendations for its potential applications in lumbar fusion.METHODSForty-five consecutive patients (involving 204 screws inserted) underwent K-wireless lumbar pedicle screw fixation with SpineMask and intraoperative neuromonitoring. Screws were inserted by percutaneous stab or Wilts...

Research paper thumbnail of Assessment and classification of subsidence after lateral interbody fusion using serial computed tomography

Journal of Neurosurgery: Spine, 2015

OBJECT Intervertebral cage settling during bone remodeling after lumbar lateral interbody fusion ... more OBJECT Intervertebral cage settling during bone remodeling after lumbar lateral interbody fusion (LIF) is a common occurrence during the normal healing process. Progression of this settling with endplate collapse is defined as subsidence. The purposes of this study were to 1) assess the rate of subsidence after minimally invasive (MIS) LIF by CT, 2) distinguish between early cage subsidence (ECS) and delayed cage subsidence (DCS), 3) propose a descriptive method for classifying the types of subsidence, and 4) discuss techniques for mitigating the risk of subsidence after MIS LIF. METHODS A total of 128 consecutive patients (with 178 treated levels in total) underwent MIS LIF performed by a single surgeon. The subsidence was deemed to be ECS if it was evident on postoperative Day 2 CT images and was therefore the result of an intraoperative vertebral endplate injury and deemed DCS if it was detected on subsequent CT scans (≥ 6 months postoperatively). Endplate breaches were categoriz...

Research paper thumbnail of Brief intraoperative heparinization and blood loss in anterior lumbar spine surgery

Journal of Neurosurgery: Spine, 2015

OBJECT The anterior approach to the lumbar spine may be associated with iliac artery thrombosis. ... more OBJECT The anterior approach to the lumbar spine may be associated with iliac artery thrombosis. Intraoperative heparin can be administered to prevent thrombosis; however, there is a concern that this will increase the procedural blood loss. The aim of this study was to examine whether intraoperative heparin can be administered without increasing blood loss in anterior lumbar spine surgery. METHODS A prospective study of consecutive anterior approaches for lumbar spine surgery was performed between January 2009 and June 2014 by a single vascular surgeon and a single spine surgeon. Patients underwent an anterior lumbar interbody fusion (ALIF) at L4–5 and/or L5–S1, a total disc replacement (TDR) at L4–5 and/or L5–S1, or a hybrid procedure with a TDR at L4–5 and an ALIF at L5–S1. Heparin was administered intravenously when arterial flow to the lower limbs was interrupted during the procedure. Heparin was usually reversed on removal of the causative retraction. RESULTS The cohort consis...

Research paper thumbnail of Indirect Foraminal Decompression Is Independent of Metabolically Active Facet Arthropathy in Extreme Lateral Interbody Fusion

Spine, 2014

Study Design. Retrospective analysis of prospectively collected, nonrandomized radiographical dat... more Study Design. Retrospective analysis of prospectively collected, nonrandomized radiographical data. Objective. To examine the relationship between the presence of preoperative metabolically active facet arthropathy (FA) and the amount of indirect foraminal decompression gained after extreme lateral interbody fusion (XLIF). Summary of Background Data. Although evidence of signifi cant radiographical indirect decompression after XLIF has been shown, the relationship between the extent of indirect decompression and the presence of potentially attenuating, FA is yet to be studied. Methods. A prospective database of consecutive patients undergoing XLIF was retrospectively analyzed. Posterior disc height, foraminal height, and cross-sectional foraminal area were measured on computed tomographic scans obtained preoperatively and 2 days postoperatively. The selected radiographical parameters were examined with respect to the presence of FA based on preoperative computed tomographic and bone scans. Results. Fifty-two consecutive patients underwent 79 levels of XLIF without direct decompression. Average age was 66.4 years and 34 (65.4%) were females. Surgery resulted in signifi cant increases in posterior disc height 3.0 to 5.7 mm (89.0% increase), P < 0.0001; foraminal height 1.4 to 1.7 cm (38.0% increase), P < 0.0001; and foraminal area 1.1 to 1.4 cm 2 (45.1% increase), P < 0.0001. These increases were independent of the presence of metabolically active arthropathy.