Reproducibility of 3D pH-weighted chemical exchange saturation transfer contrast in the healthy cervical spinal cord

Spinal cord ischemia and hypoxia can be caused by compression, injury, and vascular alterations. Measuring ischemia and hypoxia directly in the spinal cord noninvasively remains challenging. Ischemia and hypoxia alter tissue pH, providing a physiologic parameter that may be more directly related to tissue viability. Chemical exchange saturation transfer (CEST) is an MRI contrast mechanism that can be made sensitive to pH. More specifically, amine/amide concentration independent detection (AACID) is a recently developed endogenous CEST contrast that has demonstrated sensitivity to intracellular pH at 9.4 T. The goal of this study was to evaluate the reproducibility of AACID CEST measurements at different levels of the healthy cervical spinal cord at 3.0 T incorporating B1 correction. Using a 3.0 T MRI scanner, two 3D CEST scans (saturation pulse train followed by a 3D snapshot gradient-echo readout) were performed on 12 healthy subjects approximately 10 days apart, with the CEST volume centered at the C4 level for all subjects. Scan-rescan reproducibility was evaluated by examining between and within-subject coefficients of variation (CVs) and absolute AACID value differences. The C4 level of the spinal cord demonstrated the lowest within-subject CVs (4.1%-4.3%), between-subject CVs (5.6%-6.3%), and absolute AACID percent difference (5.8-6.1%). The B1 correction scheme significantly improved reproducibility (adjusted p-value = 0.002) compared with the noncorrected data, suggesting that implementing B1 corrections in the spinal cord is beneficial. It was concluded that pH-weighted AACID measurements, incorporating B1-inhomogeneity correction, were reproducible within subjects along the healthy cervical spinal cord and that optimal image quality was achieved at the center of the 3D CEST volume.

Characterizing mJOA-defined post-surgical recovery patterns in patients with degenerative cervical myelopathy

Background

Degenerative cervical myelopathy is a spinal disorder resulting in progressive cord compression and neurological deficits that are assessed using the modified Japanese Orthopedic Association (mJOA) questionnaire. It is difficult to predict which patients will recover neurological function after surgery, making it challenging for clinicians to set postoperative patient expectations. In this study, we used mJOA subscores to identify patterns of recovery and recovery timelines in patients with moderate and severe myelopathy.

Methods

Fifty-three myelopathy patients were enrolled and completed the mJOA questionnaire both pre-surgery, and six weeks and six months post-surgery. Pearson chi-square tests were performed to assess relationships of both recovery patterns and recovery timelines with severity of disease.

Results

Moderate myelopathy patients were significantly more likely than severe myelopathy patients to experience full recovery of upper extremity, lower extremity, and sensory domains. Disease severity did not significantly impact the timeline during which recovery occurs. Overall, >90% of patients experienced at least partial recovery by six months post surgery, 80% of which demonstrated it within the first six weeks.

Conclusions

This study shows the more severe the disease experienced by myelopathy patients, the more likely they will be left with permanent disabilities despite surgery. Early identification and treatment are therefore necessary to prevent worsening quality of life and increased costs of functional dependence. The recovery timelines for each subscore are similar and provide new values to guide patient expectations in their potential post-operative recovery. The overall recovery timeline is more generalizable though potentially lacking the specificity patients seek.

The importance of measuring prolactin prior to surgical management of a pituitary lesion: An illustrative case

The characterization of sellar and suprasellar lesions is reliant on patient presentation, medical imaging, and hormone profiling. Prolactinomas are the most common type of functional pituitary adenomas, accounting for up to 57%. Importantly, prolactinomas can present without clear symptoms and with doubtful or even normal imaging. A 41-year-old male patient was referred to neurosurgery for consideration for resection of a sellar lesion, as initial CT imaging suggested a large meningioma. Subsequent MRI of the sella favored macroadenoma, meningioma, and craniopharyngioma as the top differential considerations. These conditions all indicate a diagnosis that would require surgical management. Clinical evaluation of this patient did not elicit any obvious clinical features suggestive of hyperprolactinemia. Fortunately, we obtained a full hormone panel which revealed a significantly elevated prolactin level of 17,390 µg/L. Based on this elevated prolactin level, we diagnosed a pituitary giant prolactinoma. Treatment with a dopamine agonist therapy was initiated and the response confirmed this diagnosis. This case demonstrates the importance of obtaining a prolactin level prior to surgical management of a sellar lesion. Had a prolactin level not been obtained, this patient would have undergone surgical resection based on both the imaging and clinical judgment.

AB0034 INVESTIGATING THE ROLE OF ACCELERATED IMMUNESENESCENCE IN THE PATHOGENESIS OF RHEUMATOID ARTHRITIS

Background

Advancing age is recognised as a major risk factor for autoimmune inflammatory conditions, such as Rheumatoid Arthritis (RA). Despite strong associations with older age we understand little of the role ageing processes play in disease pathogenesis in RA. The immune system undergoes a dramatic remodelling with age, termed immunesenescence, which contributes towards increased risk of autoimmunity1. Previous research in patients with established RA has shown certain features of immunesenescence, such as thymic atrophy and telomere shortening in T cells, at a younger age2,3.

Objectives

In this study we aimed to determine if immunesenescence is seen in the very earliest stages of RA and therefore might be a contributor to RA pathogenesis rather than a result of the disease.

Methods

We have assessed aspects of the aged immune phenotype by immunostaining and flow cytometry4 in adults with arthralgia (n=25), undifferentiated arthritis (UA; n=41), confirmed RA of less than 3 months (n=25) and more than 3 months duration (n=78) and compared these to age and sex matched healthy controls (n=38). Nanostring methodology was used to determine gene expression changes associated with the development of RA.

Results

We observed increased features of T and B cell immunesenescence in DMARD-naïve recently diagnosed RA patients driven by reduced naïve T cells (p<0.01) and B cells (p<0.01), increased senescent (CD28-ve, CD57+ve, KLRG1+ve) T cells (p<0.01), an increased Th17/Treg ratio (p<0.01) and increased frequency of age-associated B cells (p<0.01). With the exception of naïve T cell frequency, which was reduced in UA patients (p<0.05), these changes were not seen in the very early stages of RA, namely patients with arthralgia and UA. These data suggest that immunesenescence only occurs once disease is established. Furthermore, using nanostring we have identified several biological ageing processes (DNA damage, autophagy) associated with this state of immunesenescence in RA.

Conclusion

Accelerated immune ageing is an early feature of RA and biological ageing processes represent novel targets to modulate disease progression.

References

[1]Duggal NA, Upton JA, Phillips AC, Sapey E, Lord JM (2013) An age-related numerical and functional deficit in CD19+CD24hiCD38hi B cells is associated with an increase in systemic autoimmunity. Aging Cell 12:873-881.

[2]Goronzy, J.J. and Weyand CM (2001). Thymic function and peripheral T-cell homeostasis in rheumatoid arthritis. Trends Immunol. 22(5):251-5.

[3]Steer SE, Williams FMK, Kato B, Gardner JP, Norman PJ, Hall MA, Kimra M, Vaughan R, Aviv A, Spector T (2007) Reduced telomere length in rheumatoid arthritis in independent of disease activity and duration. Ann Rheum Dis 66:476-480.

[4]Duggal NA, Pollock RD, Lazarus NR, Harridge S, Lord JM (2018). Major features of immunesenescence, including reduced thymic output, are ameliorated by high levels of physical activity in adulthood. Aging Cell 17:e12750

Disclosure of Interests

None declared

AB0091 INCREASED BIOLOGICAL AGE IN MALE PARTICIPANTS OF SWEDISH AND UK RHEUMATOID ARTHRITIS COHORTS IS NOT LINKED TO DISEASE

Background

Immunesenescence in the adaptive immune system, subsequent to thymic involution, results in compromised immunity and increased susceptibility to autoimmune disease and chronic inflammation. There are reports in the literature that immunesenescence, including thymic atrophy and telomere shortening, is accelerated in patients with rheumatoid arthritis (RA)1. What is unclear is whether RA includes accelerated biological ageing overall in addition to immune ageing which may help to explain the increased risk of age-related diseases in RA2. Recent studies have identified a set of DNA methylated sites across the genome that are highly correlated with chronological age and mortality, termed epigenetic clocks3,4 or DNAm age (DNAma), and can be used to determine an individual’s biological age.

Objectives

The aim of our study is to determine if the biological epigenetic clocks of RA patients are accelerated.

Methods

We evaluated the Horvath3 and Hannum4 epigenetic clocks of control and RA patients using published DNAm data sets, accessions GSE42861 (EIRA, Swedish cohort of 342 RA patients and 328 non-RA controls) and E-MTAB-6988 (77 RA discordant monozygotic twins).

Results

We did not detect significant differences between DNAma of RA and non-RA twins. Similarly, there were no significant differences between the DNAma of RA patients and controls from the Swedish EIRA cohort. However, we detected a significant acceleration in DNAma of male discordant twins, both RA and non-RA, by 5.4 years (p=3.29e-5) and 2.8 years (p=0.04) using the Hannum and Horvath clocks, respectively. Male participants, both control and RA patients, from the EIRA cohort also exhibited an accelerated DNAma, by 1.5 years (p=7.55e-5) using the Hannum clock but using the Horvath clock a significant DNAma acceleration, by 1.4 years (p=0.002) was detected in male RA patients from the EIRA cohort.

Conclusion

Overall, we detected a significant biological age acceleration in male participants from both RA and control groups and only found a significant difference between DNAma of Non-RA controls and RA patients for one of the epigenetic clocks. Further analysis using additional cohort data and biological clock algorithms is needed to confirm our findings.

References

[1]Goronzy, J.J. and Weyand CM (2001). Thymic function and peripheral T-cell homeostasis in rheumatoid arthritis. Trends Immunol. 22(5):251-5.

[2]Meune C, et al. (2009) Trends in cardiovascular mortality in patients with rheumatoid arthritis over 50 years: a systematic review and meta-analysis of cohort studies. Rheumatol 48:1309-1313.

[3]Horvath S (2013) DNA methylation age of human tissues and cell types. Genome Biol 14:R115.

[4]Hannum G, et al (2013) Genome-wide Methylation Profiles Reveal Quantitative Views of Human Aging Rates. Mol Cell 49:359-367.

Acknowledgements

The study was funded by FOREUM

Disclosure of Interests

None declared

Chondroblastoma of the knee in a teenager

Chondroblastoma is an uncommon osseous neoplasm that accounts for less than 1% of all bone tumors. Characteristically it arises in the epiphysis or apophysis of long bones in young patients and may extend into the metaphysis. A sixteen-year-old male presents with a 1-year history of left knee pain associated with joint stiffness and interfering with performing daily activities. Radiographic and contrast enhanced magnetic resonance imaging favored the diagnosis of chondroblastoma. This was then confirmed histologically. The clinical signs and symptoms of Chondroblastoma are usually nonspecific, pain is most often moderate and can be revealed as a result of a trauma. The definitive diagnosis is mainly pathological due to the lack of specificity of radiological findings consistent with the presented case.

Pfeiffer syndrome in an adult with previous surgical correction: A case report of CT findings

Pfeiffer syndrome, affecting roughly 1 in 100,000 individuals is characterized by acrocephalosyndactyly - the premature closure of skull sutures (craniosynostosis). These acrocephalosyndactyly syndromes which are often sporadic de novo but also autosomal dominant in inheritance can be characterized by the fact that they often involve FGFR and TWIST genes. In the presented case, a 27-year old male level three trauma admission displayed skull abnormalities on physical examination that history taking confirmed was the result of pediatric surgically corrected Pfeiffer syndrome. Noncontrast brain CT as part of his trauma work-up revealed characteristic Pfeiffer syndrome imaging pattern of midface hypoplasia, nonvisualization of coronal and sagittal sutures, and a degree of obstructive hydrocephalus. Pfeiffer syndrome requires extensive pediatric surgery often with poor adult follow up. The case presented provides good visualization of characteristic skull abnormalities in a surgically corrected adult. By virtue of imaging an adult, this provides readers with a unique look at the long-term viability and the body's resulting physiological adaptations of the extensive mandatory pediatric surgery these patients undergo.

Spinal cord compression is associated with brain plasticity in degenerative cervical myelopathy

The impact of spinal cord compression severity on brain plasticity and prognostic determinates is not yet fully understood. We investigated the association between the severity of spinal cord compression in patients with degenerative cervical myelopathy, a progressive disease of the spine, and functional plasticity in the motor cortex and subcortical areas using functional magnetic resonance imaging. A 3.0 T MRI scanner was used to acquire functional images of the brain in 23 degenerative cervical myelopathy patients. Patients were instructed to perform a structured finger-tapping task to activate the motor cortex to assess the extent of cortical activation. T₂-weighted images of the brain and spine were also acquired to quantify the severity of spinal cord compression. The observed blood oxygen level-dependent signal increase in the contralateral primary motor cortex was associated with spinal cord compression severity when patients tapped with their left hand (r = 0.49, P = 0.02) and right hand (r = 0.56, P = 0.005). The volume of activation in the contralateral primary motor cortex also increased with spinal cord compression severity when patients tapped with their left hand (r = 0.55, P = 0.006) and right hand (r = 0.45, P = 0.03). The subcortical areas (cerebellum, putamen, caudate and thalamus) also demonstrated a significant relationship with compression severity. It was concluded that degenerative cervical myelopathy patients with severe spinal cord compression recruit larger regions of the motor cortex to perform finger-tapping tasks, which suggests that this adaptation is a compensatory response to neurological injury and tissue damage in the spinal cord.

Differential effects of transcranial direct current stimulation on antiphase and inphase motor tasks: A pilot study

Ageing is associated with a decline in motor function that critically interferes with activities of daily living involving manual dexterity. Transcranial direct current stimulation (tDCS) is a form of non-invasive brain stimulation that has been shown to enhance manual dexterity in healthy aging adults. The supplementary motor area (SMA) is involved in motor preparation and bimanual control; therefore, bihemispheric tDCS incorporating the SMA may preferentially enhance bimanual motor movements in healthy older adults. The aim of the current study was to determine if tDCS incorporating SMA could improve manual dexterity in older adults. Twenty-four adults, aged 67-84 participated in this double-blind, randomized, cross over design, pilot study. One group of participants (n = 17) were randomized to receive stimulation or sham on their first visit and received the contrary on their second visit, seven days later. A second group of participants (n = 10) received three consecutive days of tDCS while performing a motor task. Participants performed unimanual and bimanual hand movements while receiving 2 mA of tDCS. The total time for participants to complete three trials of each task was recorded. No significant differences in performance times were observed between single or tri session tDCS and sham conditions. However, tDCS had opposing effects on the motor consolidation of anti-phase and in-phase bimanual tasks. During the tri session paradigm, older adults improved performance learning of antiphase bimanual movements more quickly than inphase bimanual movements, suggesting a different mechanism of action of these two movements.

Biomechanical evaluation of the ProDisc-C stability following graded posterior cervical injury

OBJECTIVEThere are limited data regarding the implications of revision posterior surgery in the setting of previous cervical arthroplasty (CA). The purpose of this study was to analyze segmental biomechanics in human cadaveric specimens with and without CA, in the context of graded posterior resection.METHODSFourteen human cadaveric cervical spines (C3-T1 or C2-7) were divided into arthroplasty (ProDisc-C, n = 7) and control (intact disc, n = 7) groups. Both groups underwent sequential posterior element resections: unilateral foraminotomy, laminoplasty, and finally laminectomy. Specimens were studied sequentially in two different loading apparatuses during the induction of flexion-extension, lateral bending, and axial rotation.RESULTSRange of motion (ROM) after artificial disc insertion was reduced relative to that in the control group during axial rotation and lateral bending (13% and 28%, respectively; p < 0.05) but was similar during flexion and extension. With sequential resections, ROM increased by a similar magnitude following foraminotomy and laminoplasty in both groups. Laminectomy had a much greater effect: mean (aggregate) ROM during flexion-extension, lateral bending, and axial rotation was increased by a magnitude of 52% following laminectomy in the setting of CA, compared to an 8% increase without arthroplasty. In particular, laminectomy in the setting of CA introduced significant instability in flexion-extension, characterized by a 90% increase in ROM from laminoplasty to laminectomy, compared to a 16% increase in ROM from laminoplasty to laminectomy without arthroplasty (p < 0.05).CONCLUSIONSForaminotomy and laminoplasty did not result in significant instability in the setting of CA, compared to controls. Laminectomy alone, however, resulted in a significant change in biomechanics, allowing for significantly increased flexion and extension. Laminectomy alone should be used with caution in the setting of previous CA.

Motor network recovery in patients with chronic spinal cord compression: a longitudinal study following decompression surgery

OBJECTIVE The authors used functional MRI to assess cortical reorganization of the motor network after chronic spinal cord compression and to characterize the plasticity that occurs following surgical intervention. METHODS A 3-T MRI scanner was used to acquire functional images of the brain in 22 patients with reversible cervical spinal cord compression and 10 control subjects. Controls performed a finger-tapping task on 3 different occasions (baseline, 6-week follow-up, and 6-month follow-up), whereas patients performed the identical task before surgery and again 6 weeks and 6 months after spinal decompression surgery. RESULTS After surgical intervention, an increased percentage blood oxygen level-dependent signal and volume of activation was observed within the contralateral and ipsilateral motor network. The volume of activation of the contralateral primary motor cortex was associated with functional measures both at baseline (r = 0.55, p < 0.01) and 6 months after surgery (r = 0.55, p < 0.01). The percentage blood oxygen level-dependent signal of the ipsilateral supplementary motor area 6 months after surgery was associated with increased function 6 months after surgery (r = 0.48, p < 0.01). CONCLUSIONS Plasticity of the contralateral and ipsilateral motor network plays complementary roles in maintaining neurological function in patients with spinal cord compression and may be critical in the recovery phase following surgery.

Bilateral caudate nucleus infarcts: A case report of a rare complication following endoscopic resection of a tuberculum sellae meningioma

Background:

We present a rare complication of bilateral caudate infarcts and necrosed nasoseptal flaps after endoscopic transsphenoidal resection of tuberculum sellae meningioma. This case highlights the importance of early and accurate diagnosis and treatment of a postoperative cerebrospinal fluid (CSF) leak and associated bacterial meningitis, and reviews any existing guidelines regarding its management.

Case Description:

A 54-year-old otherwise healthy man presented with progressive bitemporal hemianopsia. Magnetic resonance imaging of the head revealed a large, homogeneously enhancing sellar and suprasellar mass consistent with a meningioma. An endoscopic endonasal transsphenoidal approach was performed to resect the tuberculum sellae meningioma. The patient developed basal bacterial meningitis secondary to a CSF leak, requiring repair on two separate occasions. At the time of both repairs, there was evidence of necrosis of the nasoseptal flaps used for the repairs. Soon after the diagnosis of meningitis, the patient developed bilateral caudate infarcts.

Conclusion:

This report discusses the possible underlying etiologies for the bilateral caudate infarcts and necrosed flaps including bacterial meningitis with associated local vasospasm of nearby vessels resulting in infarction. This case emphasizes the importance of concise management of postendoscopic CSF leak and discusses the guidelines regarding antimicrobial therapy and the management of lumbar drains.

Metabolite and functional profile of patients with cervical spondylotic myelopathy

OBJECTIVE

The goal of this study was to compare the recovery of neuronal metabolism and functional reorganization in the primary motor cortex (M1) between mild and moderate cervical spondylotic myelopathy (CSM) following surgical intervention.

METHODS

Twenty-eight patients with CSM underwent 3-T MRI scans that included spectroscopy and functional MRI, before surgery and 6 months postsurgery. The classification of severity was based on the modified Japanese Orthopaedic Association questionnaire. Mild and moderate myelopathy were defined by modified Japanese Orthopaedic Association scores > 12 of 18 (n = 15) and 9–12 (n = 13), respectively. Ten healthy control subjects underwent 2 MRI scans 6 months apart. Metabolite levels were measured in the M1 contralateral to the greater deficit side in patients with CSM and on both sides in the controls. Motor function was assessed using a right finger–tapping paradigm and analyzed with BrainVoyager QX.

RESULTS

Patients with mild CSM had a lower preoperative N-acetylaspartate to creatine (NAA/Cr) ratio compared with moderate CSM, suggesting mitochondrial dysfunction. Postsurgery, NAA/Cr in moderate CSM decreased to the levels observed in mild CSM. Preoperatively, patients with mild CSM had a larger volume of activation (VOA) in the M1 than those with moderate CSM. Postoperatively, the VOAs were comparable between the mild and moderate CSM groups and had shifted toward the primary sensory cortex.

CONCLUSIONS

The NAA/Cr ratio and VOA size in the M1 can be used to discriminate between mild and moderate CSM. Postsurgery, the metabolite profile of the M1 did not recover in either group, despite significant clinical improvement. The authors proposed that metabolic impairment in the M1 may trigger the recruitment of adjacent healthy cortex to achieve functional recovery.

Zinc oxide tetrapods inhibit herpes simplex virus infection of cultured corneas

PURPOSE

Infection of the human cornea by herpes simplex virus type-1 (HSV-1) can cause significant vision loss. The purpose of this study was to develop an ex vivo model to visualize viral growth and spread in the cornea. The model was also used to analyze cytokine production and study the antiviral effects of zinc oxide tetrapods.

METHODS

A β-galactosidase-expressing recombinant virus, HSV-1(KOS)tk12, was used to demonstrate the ability of the virus to enter and develop blue plaques on human corneal epithelial (HCE) cells and corneal tissues. Freshly obtained porcine corneas were cultured and then scratched before infection with HSV-1(KOS)tk12. The blue plaques on the corneas were imaged using a stereomicroscope. Western blot analysis for HSV-1 proteins was performed to verify HSV-1 infection of the cornea. Using the ex vivo model, zinc oxide tetrapods were tested for their anti-HSV-1 potential, and a cytokine profile was developed to assess the effects of the treatment.

RESULTS

Cultured corneas and the use of β-galactosidase-expressing HSV-1(KOS)tk12 virus can provide an attractive ex vivo model to visualize and study HSV-1 entry and spread of the infection in tissues. We found that unlike cultured HCE cells, which demonstrated nearly 100% infectivity, HSV-1 infection of the cultured cornea was more restrictive and took longer to develop. We also found that the zinc oxide tetrapod-shaped nano- and microstructures inhibited HSV infection of the cultured cells, as well as the cultured corneas. The cytokine profile of the infected samples was consistent with previous studies of HSV-1 corneal infection.

CONCLUSIONS

The ability to visualize HSV-1 growth and spread in corneal tissues can provide new details about HSV-1 infection of the cornea and the efficacy of new cornea-specific antiviral drug candidates. The ex vivo model also demonstrates antiviral effects of zinc oxide tetrapods and adequately portrays the drug delivery issues that cornea-specific treatments face.

Quantitative evaluation of vision-related and health-related quality of life after endoscopic transsphenoidal surgery for pituitary adenoma

OBJECTIVE Endoscopic resection of pituitary adenomas has been reported to improve vision function in up to 80%-90% of patients with visual impairment due to these adenomas. It is unclear how these reported rates translate into improvement in visual outcomes and general health as perceived by the patients. The authors evaluated self-assessed health-related quality of life (HR-QOL) and vision-related QOL (VR-QOL) in patients before and after endoscopic resection of pituitary adenomas. METHODS The authors prospectively collected data from 50 patients who underwent endoscopic resection of pituitary adenomas. This cohort included 32 patients (64%) with visual impairment preoperatively. Twenty-seven patients (54%) had pituitary dysfunction, including 17 (34%) with hormone-producing tumors. Patients completed the National Eye Institute Visual Functioning Questionnaire and the 36-Item Short Form Health Survey preoperatively and 6 weeks and 6 months after surgery. RESULTS Patients with preoperative visual impairment reported a significant impact of this condition on VR-QOL preoperatively, including general vision, near activities, and peripheral vision; they also noted vision-specific impacts on mental health, role difficulties, dependency, and driving. After endoscopic resection of adenomas, patients reported improvement across all these categories 6 weeks postoperatively, and this improvement was maintained by 6 months postoperatively. Patients with preoperative pituitary dysfunction, including hormone-producing tumors, perceived their general health and physical function as poorer, with some of these patients reporting improvement in perceived general health after the endoscopic surgery. All patients noted that their ability to work or perform activities of daily living was transiently reduced 6 weeks postoperatively, followed by significant improvement by 6 months after the surgery. CONCLUSIONS Both VR-QOL and patient's perceptions of their ability to do work and perform other daily activities as a result of their physical health significantly improved by 6 months after endoscopic resection of pituitary adenoma. The use of multidimensional QOL questionnaires provides a precise assessment of perceived outcomes after endoscopic surgery.

Cervical Spondylotic Myelopathy: Metabolite Changes in the Primary Motor Cortex after Surgery

Purpose To characterize longitudinal metabolite alterations in the motor cortex of patients with cervical spondylotic myelopathy (CSM) by using proton magnetic resonance (MR) spectroscopy and to evaluate white matter integrity with diffusion-tensor imaging in patients who are recovering neurologic function after decompression surgery. Materials and Methods Informed written consent was obtained for all procedures and the study was approved by Western University's Health Sciences Research Ethics Board. Twenty-eight patients with CSM and 10 healthy control subjects were prospectively recruited and underwent two separate 3-T MR imaging examinations 6 months apart. Patients with CSM underwent surgery after the first examination. N-acetylaspartate (NAA), an indicator of neuronal mitochondrial function, normalized to creatine (Cr) levels were measured from the motor cortex contralateral to the greater functional deficit side in the patient group and on both sides in the control group. Fractional anisotropy and mean diffusivity were measured by means of diffusion-tensor imaging in the white matter adjacent to the motor and sensory cortices of the hand and the entire cerebral white matter. Clinical data were analyzed by using Student t tests. Results In patients with CSM, NAA normalized to Cr (NAA/Cr) levels were significantly lower 6 months after surgery (1.48 ± 0.08; P < .03) compared with preoperative levels (1.73 ± 0.09), despite significant improvement in clinical questionnaire scores. Fractional anisotropy and mean diffusivity were the same (P > .05) between the patient and control groups in all measured regions at all time points. Conclusion NAA/Cr levels decreased in the motor cortex in patients with CSM 6 months after successful surgery. Intact white matter integrity with decreased NAA/Cr levels suggests that mitochondrial metabolic dysfunction persists after surgery. ^© RSNA, 2016 Online supplemental material is available for this article.

Does design matter? Cervical disc replacements under review

The present article reviews the design rationale of currently available cervical disc replacements. Recent prospective randomized control trials comparing cervical disc replacement and anterior fusion have demonstrated safety as well as equal or superior clinical results. Increasingly, more devices are becoming available on the market. Understanding design rationale will provide context for the surgeon to optimize decision making for the most appropriate prosthesis. Cervical arthroplasty is a technique that is undergoing rapid design refinement and development. Further improvements in device design will enable patient-specific device selection. Understanding the design rationale and complication profile of each device will improve clinical and radiographic outcomes.

Retrospective review of percutaneous synovial cyst ruptures: increased thickness of the T2 hypointense rim on post-rupture MRI may be associated with need for subsequent surgery

OBJECTIVE

To analyze MRI characteristics of lumbar facet synovial cysts and distinguish those requiring subsequent surgical management for recurrence, after percutaneous synovial cyst rupture.

METHODS AND MATERIALS

Retrospective chart review conducted in patients undergoing percutaneous synovial cyst rupture between February 2012 and April 2015. Pre- and post-percutaneous rupture procedure MRI spine studies were serially reviewed. Synovial cyst sizes, T1 and T2 signal characteristics and changes therein, T2 hypointense (or 'dark rim') thickness and change, and changes in the complexity of cyst signals were compared. Operative notes for patients who underwent subsequent surgical removal of recurrent synovial cysts were reviewed.

RESULTS

24 patients received 41 percutaneous synovial cyst rupture procedures, with a technical success rate of 82.9%. There was a significant difference in the mean increased thickness of the T2 hypointense rim on the first post-rupture MRI scan (p=0.0411) between patients requiring subsequent surgery and those who did not. There was a significant difference in the average sizes of synovial cysts before the procedure (p=0.0483) in those requiring subsequent surgery and those who did not. Five complications were noted (12.2%), mostly involving leg pain or weakness. Of the nine patients who underwent subsequent surgery post-synovial cyst rupture, six of the surgeries had recorded difficulty pertaining to scarring and/or adherence of the cyst to dura.

CONCLUSIONS

A larger increase in thickness of the T2 hypointense rim on the first post-rupture MRI scan and a larger synovial cyst size were associated with the need for subsequent surgical resection.

N-acetylaspartate in the motor and sensory cortices following functional recovery after surgery for cervical spondylotic myelopathy

OBJECTIVE Cervical spondylotic myelopathy (CSM) is the most common cause of reversible spinal cord dysfunction in people over the age of 55 years. Following surgery for symptomatic CSM, patients demonstrate motor improvement early in the postoperative course, whereas sensory improvement can lag behind. The authors of the present study hypothesized that changes in the concentration of N-acetylaspartate (NAA) in the motor and sensory cortices in the brain would emulate the time course of neurological recovery following decompression surgery for CSM. Their aim was to compare and contrast how metabolite levels in the motor and sensory cortices change after surgery to reverse downstream spinal cord compression. METHODS Twenty-four patients with CSM and 8 control subjects were studied using proton MR spectroscopy (¹H-MRS) images acquired on a 3.0-T Siemens MRI unit. The ¹H-MRS data (TE 135 msec, TR 2000 msec) were acquired to measure absolute levels of NAA from the motor and sensory cortices in the cerebral hemisphere contralateral to the side of greater deficit at baseline in each subject. Data were also acquired at 6 weeks and 6 months following surgery. Control subjects were also evaluated at 6 weeks and 6 months following baseline data acquisition. Neurological function was measured in each subject at all time points using the Neck Disability Index (NDI), modified Japanese Orthopaedic Association (mJOA) questionnaire, and the American Spinal Injury Association (ASIA) neurological classification. RESULTS In the motor cortex of patients, NAA levels decreased significantly (p < 0.05) at 6 weeks and 6 months postsurgery compared with baseline levels. In the sensory cortex of patients, NAA levels decreased significantly (p < 0.05) only at 6 months after surgery compared with baseline and 6-week levels. No significant changes in NAA were found in control subjects. Clinical scores demonstrated significant (p < 0.05) motor recovery by 6 weeks, whereas sensory improvements (p < 0.05) appeared at only 6 months. CONCLUSIONS Findings suggest that metabolite changes in both the motor and sensory cortices mimic the time course of functional motor and sensory recovery in patients with CSM. The temporal course of neurological recovery may be influenced by metabolic changes in respective cortical regions.

Quantitative evaluation of headache severity before and after endoscopic transsphenoidal surgery for pituitary adenoma

OBJECT The relationship between headaches, pituitary adenomas, and surgical treatment of pituitary adenomas remains unclear. The authors assessed the severity and predictors of self-reported headaches in patients referred for surgery of pituitary adenomas and evaluated the impact of endoscopic transsphenoidal surgery on headache severity and quality of life (QOL). METHODS In this prospective study, 79 patients with pituitary adenomas underwent endoscopic transsphenoidal resection and completed the Headache Impact Test (HIT-6) and the 36-Item Short Form Health Survey (SF-36) QOL questionnaire preoperatively and at 6 weeks and 6 months postoperatively. RESULTS Preoperatively, 49.4% of patients had mild headache severity, 13.9% had moderate severity, 13.9% had substantial severity, and 22.8% had intense severity. Younger age and hormone-producing tumors predisposed greater headache severity, while tumor volume, suprasellar extension, chiasmal compression, and cavernous sinus invasion of the pituitary tumors did not. Preoperative headache severity was found to be significantly associated with reduced scores across all SF-36 QOL dimensions and most significantly associated with mental health. By 6 months postoperatively, headache severity was reduced in a significant proportion of patients. Of the 40 patients with headaches causing an impact on daily living (moderate, substantial, or intense headache), 70% had improvement of at least 1 category on HIT-6 by 6 months postoperatively, while headache worsened in 7.6% of patients. The best predictors of headache response to surgery included younger age, poor preoperative SF-36 mental health score, and hormone-producing microadenoma. CONCLUSIONS The results of this study confirm that surgery can significantly improve headaches in patients with pituitary adenomas by 6 months postoperatively, particularly in younger patients whose preoperative QOL is impacted. A larger multicenter study is underway to evaluate the long-term effect of surgery on headaches in this patient group.

Controversies in Cervical Discectomy and Fusion: Practice Patterns Among Canadian Surgeons

Objective:

Optimal fusion technique and peri-operative management of patients undergoing anterior cervical discectomy (ACD) is unclear.We document current practice patterns among Canadian spinal surgeons regarding the surgical management of single level degenerative cervical spondylosis.

Methods:

We conducted a web-based survey of neurosurgeons and spinal orthopedic surgeons in Canada. We asked questions pertaining to the management of single level cervical degenerative disc disease causing radiculopathy and/or myelopathy, including frequency of fusion following single-level discectomy, preferred fusion technique, indications and frequency of use of anterior plating, and use of an external cervical orthosis following surgery. Demographic factors assessed included training background, type and length of practice.

Results:

Sixty respondents indicated that their practice involved at least 5% spine surgery and were included in further analysis. Neurosurgeons comprised 59% of respondents, and orthopedic surgeons 41%. Fusion was employed 93% of the time following ACD; autologous bone was the preferred fusion material, used in 76% of cases. Neurosurgeons employed anterior cervical plates in 42% of anterior cervical discectomy and fusion cases, whereas orthopedic surgeons used them 70% of the time. External cervical orthoses were recommended for 92% of patients without plates and 61% of patients with plates. Surgeons who had been in practice for less than five years were most likely to be performing spinal surgery, using anterior cervical plates, and recommending the postoperative use of cervical orthoses.

Conclusion:

Practice patterns vary among Canadian surgeons, although nearly all employ fusion and many use instrumentation for single-level ACD. Training background, and type and length of practice influence practice habits.

Case of the month: April 1998--30 year old male with perineal numbness

A 30-year-old male presented with a 2 year progressive course of bowel and bladder dysfunction, mild leg weakness and sensory abnormalities in sacral dermatomes. MRI showed an intra-axial conus medullaris lesion which was excised and identified as a ganglioglioma. The case presents the typical clinical course and histopathology of this unusual lesion which carries a favorable prognosis after gross total removal. Preoperative neurological function in such patients is highly predictive of post-operative outcome.

Kinematic analysis following implantation of the PRESTIGE LP

Background

The clinical success of cervical arthroplasty hinges on the ability to preserve or improve the biomechanics of the functional spinal unit. The purpose of this study was to conduct a radiologic assessment of kinematic parameters preimplantation and postimplantation of the PRESTIGE LP Cervical Disc System (Medtronic, Memphis, Tennessee).

Methods

A total of 120 radiographs of 20 patients following single-level implantation of the PRESTIGE LP were retrospectively reviewed. Static and dynamic radiologic assessments were performed before surgery and at 1 year postoperation. Kinematic parameters including range of motion (ROM), horizontal translation, center of rotation (COR X, Y), anterior disc height and posterior disc height, and disc angle and shell angle were assessed for each spinal level using quantitative motion analysis software. Clinical outcomes were assessed using the short form health survey physical component scores and mental component scores.

Results

The mean physical component scores and mental component scores of the short form health survey (SF-36) improved significantly following surgery. At 1 year postoperation, ROM, translation, and COR X were preserved. The COR Y shifted superiorly from 3.17 ± 2.08 mm preoperation to 0.98 ± 2.23 mm postoperation (P < .001). The anterior disc height and posterior disc height were significantly increased following surgery (3.97 ± 1.01 to 4.78 ± 1.11 mm and 3.04 ± 0.69 to 3.66 ± 0.61 mm, respectively; P < .01). The preoperative disc angle was 3.32° ± 2.92° and the postoperative shell angle was 1.11° ± 4.29°, with a mean change of −2.22° ± 4.63° (P < .05).

Conclusions

The PRESTIGE LP maintained preoperative ROM, translation, and COR X values. The postoperative COR Y value changed significantly by shifting superiorly, accompanied by an increase in DH. There was a loss of lordosis at the level of surgery, with the PRESTIGE LP endplates having an almost parallel endplate configuration.

Long-term kinematic analysis of cervical spine after single-level implantation of Bryan cervical disc prosthesis

BACKGROUND CONTEXT

Cervical arthroplasty theoretically reduces the risk of adjacent level disc degeneration and segmental instability that may be seen after a cervical fusion. An essential argument in confirming the utility of cervical arthroplasty is long-term confirmation that cervical disc replacements can maintain physiological kinematics at the index and adjacent levels.

PURPOSE

The purpose of this in vivo prospective study was to characterize the long-term segmental kinematic outcomes after cervical arthroplasty.

STUDY DESIGN/SETTING

Prospective cohort study.

PATIENT SAMPLE

Twenty patients with a 5-year clinical follow-up who underwent anterior cervical discectomy with insertion of the Bryan cervical disc.

OUTCOME MEASURES

Physiological measures (kinematic analysis of lateral neutral, flexion, and extension radiographic imaging).

METHODS

Twenty consecutive patients with degenerative disc disease were followed with regular radiographic imaging after implantation of the Bryan cervical disc prosthesis. Lateral neutral, flexion, and extension radiographs (n=240) were analyzed using Quantitative Motion Analysis software (Medical Metrics, Inc., Houston, TX, USA) to measure the biomechanical profile at the index level and adjacent levels up to 5 years after surgery. Parameters collected included range of motion (ROM), functional spinal unit (FSU) angle, anterior and posterior disc heights, sagittal translation, and center of rotation (COR).

RESULTS

Biomechanics of the implanted artificial cervical disc was maintained up to 5 years with no significant changes in ROM, FSU angle, disc height, sagittal translation, and COR values when compared with early postoperative performance. Artificial discs were able to adequately restore and maintain preoperative kinematics. Early differences seen in disc height and FSU angle did not change during the duration of follow-up. No significant kyphotic changes or decrease in ROM were seen at the adjacent spinal levels.

CONCLUSIONS

The Bryan cervical disc prosthesis provides for a durable solution for functional spinal motion at the operated level and maintained the preoperative kinematics at adjacent levels at the 5-year follow-up.

Biomechanics of a fixed-center of rotation cervical intervertebral disc prosthesis

BACKGROUND

Past in vitro experiments studying artificial discs have focused on range of motion. It is also important to understand how artificial discs affect other biomechanical parameters, especially alterations to kinematics. The purpose of this in vitro investigation was to quantify how disc replacement with a ball-and-socket disc arthroplasty device (ProDisc-C; Synthes, West Chester, Pennsylvania) alters biomechanics of the spine relative to the normal condition (positive control) and simulated fusion (negative control).

METHODS

Specimens were tested in multiple planes by use of pure moments under load control and again in displacement control during flexion-extension with a constant 70-N compressive follower load. Optical markers measured 3-dimensional vertebral motion, and a strain gauge array measured C4-5 facet loads.

RESULTS

Range of motion and lax zone after disc replacement were not significantly different from normal values except during lateral bending, whereas plating significantly reduced motion in all loading modes (P < .002). Plating but not disc replacement shifted the location of the axis of rotation anteriorly relative to the intact condition (P < 0.01). Coupled axial rotation per degree of lateral bending was 25% ± 48% greater than normal after artificial disc replacement (P = .05) but 37% ± 38% less than normal after plating (P = .002). Coupled lateral bending per degree of axial rotation was 37% ± 21% less than normal after disc replacement (P < .001) and 41% ± 36% less than normal after plating (P = .001). Facet loads did not change significantly relative to normal after anterior plating or arthroplasty, except that facet loads were decreased during flexion in both conditions (P < .03).

CONCLUSIONS

In all parameters studied, deviations from normal biomechanics were less substantial after artificial disc placement than after anterior plating.

Olfactory outcomes following endoscopic pituitary surgery with or without septal flap reconstruction: a randomized controlled trial

BACKGROUND

Postoperative hyposmia and anosmia is an often overlooked complication of endoscopic pituitary surgery. Septal flaps have been utilized as a strategy for repairing and preventing postoperative cerebrospinal fluid (CSF) leaks. The olfactory impact of raising this flap for sellar reconstruction and CSF repair needs qualitative assessment. This study aims to ascertain the effect of the Hadad-Bassagasteguy (HB) flap on olfaction in endoscopic pituitary surgery.

METHODS

In this randomized controlled trial, patients undergoing pituitary surgery underwent computerized randomization. Those in Group 1 all had HB flaps raised and placed for sellar floor defects. Those in Group 2 underwent reconstruction with synthetic or nonautologous materials. The University of Pennsylvania Smell Identification Test (UPSIT) was administered preoperatively and 6 months postoperatively. Results were analyzed using nonparametric tests.

RESULTS

Twenty subjects were enrolled, 10 in each group. Eight subjects in Group 1 vs 3 in Group 2 had intraoperative CSF leak. All were repaired intraoperatively and none required additional intervention. Preoperatively, UPSIT scores were not significantly different between groups (p = 0.62). Preoperative vs postoperative comparisons were significant for a decrease in scores in both groups postoperatively (Group 1, p < 0.001; Group 2, p < 0.001). Those undergoing HB flap reconstruction had significantly worse scores postoperatively (p = 0.001).

CONCLUSION

Endoscopic pituitary surgery results in decreased olfaction with or without deploying a septal flap. However, use of the HB flap for reconstruction can worsen hyposmia at least 6 months after surgery. Olfaction should be considered when use of the HB flap is planned.

Retinotopic organization of the visual cortex before and after decompression of the optic chiasm in a patient with pituitary macroadenoma

Compression induced by a pituitary tumor on the optic chiasm can generate visual field deficits, yet it is unknown how this compression affects the retinotopic organization of the visual cortex. It is also not known how the effect of the tumor on the retinotopic organization of the visual cortex changes after decompression. The authors used functional MRI (fMRI) to map the retinotopic organization of the visual cortex in a 68-year-old right-handed woman before and 3 months after surgery for a recurrent pituitary macroadenoma. The authors demonstrated that longitudinal changes in visual field perimetry, as assessed by the automated Humphrey visual field test, correlated with longitudinal changes in fMRI activation in a retinotopic manner. In other words, after decompression of the optic chiasm, fMRI charted the recruitment of the visual cortex in a way that matched gains in visual field perimetry. On the basis of this case, the authors propose that fMRI can chart neural plasticity of the visual cortex on an individual basis and that it can also serve as a complementary tool in decision making with respect to management of patients with chiasmal compression.

Sphenoid sinus septations: unpredictable anatomic landmarks in endoscopic pituitary surgery

OBJECTIVE

We sought to determine whether sphenoid sinus septations could be used as predictable landmarks to identify the internal carotid artery prominence.

METHODS

Fifty-six preoperative, high-resolution computed tomographic scans were identified between January 2007 and December 2009 on patients undergoing endoscopic transsphenoidal pituitary tumour resection. The number and termination locations of sphenoid sinus septations were noted, and their relationship to the internal carotid artery prominence was studied.

RESULTS

In this series, each sphenoid sinus contained a mean of 1.57 septations. We analyzed 88 sphenoid sinus septations and found only 17% inserting at either internal carotid artery prominence.

CONCLUSION

In our study, the presence of sphenoid sinus septations could not be reliably used as a surgical landmark to predict the location of the internal carotid artery. Our article stands in contrast to other literature on this topic.

Case of sparganosis: a diagnostic dilemma

Sparganosis, also known as larval diphyllobothriasis, is a rare disease of humans as man is not a natural host in the life cycle of Spirometra spp. Diagnosis of the latter is difficult as it mimics other conditions that commonly cause subcutaneous or visceral fluid collection. Clinical diagnosis of this particular case was also erroneously labelled as tuberculosis but later labelled as a case of sparganosis. To the best of our knowledge, this is the first case from India where a sparganum-like parasite was isolated in drain fluid from the perinephric area.

Analysis of in vivo kinematics of 3 different cervical devices: Bryan disc, ProDisc-C, and Prestige LP disc

OBJECT

Cervical arthroplasty has emerged as a means of preventing adjacent segment disease by preserving motion, restoring sagittal balance, and mimicking natural spinal kinematics. The purpose of this retrospective in vivo study was to characterize the impact of arthroplasty on sagittal balance and segmental kinematics of the cervical spine.

METHODS

Sixty patients receiving the Bryan disc, ProDisc-C, or Prestige LP disc were retrospectively analyzed. Only single-level arthroplasty cases were included in this study. Lateral dynamic radiographs of the cervical spine were evaluated using quantitative measurement analysis software to determine the kinematics at the index level both preoperatively and 1 year postoperatively. Collected parameters included range of motion (ROM), disc angles, shell angles, anterior and posterior disc heights (ADHs/PDHs), translation, and center of rotation (COR). Preoperative and postoperative data were compared using the Student t-test, with p < 0.05 indicating significance.

RESULTS

The Bryan and Prestige LP discs preserved motion, whereas the ProDisc-C increased segmental ROM from extension to flexion. Following surgery, the Bryan disc exhibited significant shell angle kyphosis, while ProDisc-C and Prestige LP retained lordosis. Both ADHs and PDHs decreased following insertion of the Bryan disc. In contrast, the ProDisc-C increased the ADHs and PDHs by 80% and 52%, respectively, and the Prestige LP disc increased the ADHs and PDHs by 20%. Only the ProDisc-C demonstrated significant translation of 0.7 mm. The ProDisc-C shifted the COR x by 0.9 mm anteriorly, while the Prestige LP disc demonstrated a significant superior shift of 2.2 mm in COR y.

CONCLUSIONS

All discs adequately maintained ROM at the surgical level. The greatest difference among the 3 devices was in the disc height and index angle measurements.

Olfactory outcomes after endoscopic transsphenoidal pituitary surgery

BACKGROUND

Olfaction has been demonstrated to have a great impact on patients' lives. Transsphenoidal endoscopic pituitary surgery is associated with potentially significant damage to olfactory tissues, but to date this issue has been only poorly documented in the literature.

STUDY DESIGN

Prospective cohort study comparing olfactory outcomes pre- and postpituitary surgery.

METHOD

Patients were administered the University of Pennsylvania Smell Identification Test (UPSIT) preoperatively and again at 6 months postoperatively. The endoscopic transsphenoidal pituitary surgery was carried out using a full middle turbinate preservation protocol. A Hadad-Bassagasteguy (HB) vascularized septal flap was raised in each case. Secondary outcomes included Lund-Kennedy endoscopy scores (LKES) and patient self-report of olfactory disturbance. The results were analysed using a paired t-tests.

RESULTS

Seventeen patients met inclusion criteria for the study. Mean preoperative UPSIT value was 37.2 (normosmia), and mean postoperative UPSIT value was 30.8 (moderate hyposmia) (P < .001). All patients were fully healed with normal LKES scores by 6 months. All patients complained of their olfactory dysfunction.

CONCLUSIONS

This study is the first to describe postoperative olfactory perturbations suffered by patients undergoing endoscopic transsphenoidal pituitary surgery. We hypothesize that olfactory impairment results from use of the HB flap. We recommend that the possibility of permanent olfactory changes be added to routine patient counseling and consent for this procedure, and that HB flaps be raised judiciously during trannssphenoidal endoscopic procedures.

Changes in functional magnetic resonance imaging cortical activation after decompression of cervical spondylosis: case report

BACKGROUND AND IMPORTANCE

Spinal cord compression may induce cortical reorganization. This study follows a patient with cervical spondylotic myelopathy to investigate changes in cortical activation before and after decompressive surgery. The relationship with functional recovery is also described.

CLINICAL PRESENTATION

A 37-year-old right-hand-dominant man presented a 1-month history of rapidly worsening right-hand clumsiness, right-sided hemiparesis, and gait difficulties. Physical examination confirmed severe right-sided weakness, impaired dexterity, hyperreflexia, and wide-based gait. The patient underwent blood oxygenation level-dependent functional magnetic resonance imaging at 4 T. Images were obtained before and 6 months after an anterior cervical discectomy with insertion of an artificial disk. Blood oxygenation level-dependent functional magnetic resonance imaging was used to detect changes in cortical activation over time during a finger-tapping (motor) paradigm. Improvement in clinical function was recorded with validated clinical tools, including the Japanese Orthopedic Association scale for cervical spondylotic myelopathy, the Nurick neurological function score, and the Neck Disability Index, along with clinical examination.

CONCLUSION

After decompressive cervical spine surgery in a patient with cervical spondylotic myelopathy, functional magnetic resonance imaging detected increased cortical activation in the primary motor cortex during finger tapping. These changes occurred concomitantly with improvement in motor function. Upper- and lower-extremity motor subscores of the Japanese Orthopedic Association scale demonstrated 40% and 43% improvement, respectively. These observations suggest that cortical reorganization or recruitment may accompany the recovery of function after spinal cord injury.

Biomechanics of a posture-controlling cervical artificial disc: mechanical, in vitro, and finite-element analysis

Different methods have been described by numerous investigators for experimentally assessing the kinematics of cervical artificial discs. However, in addition to understanding how artificial discs affect range of motion, it is also clinically relevant to understand how artificial discs affect segmental posture. The purpose of this paper is to describe novel considerations and methods for experimentally assessing cervical spine postural control in the laboratory. These methods, which include mechanical testing, cadaveric testing, and computer modeling studies, are applied in comparing postural biomechanics of a novel postural control arthroplasty (PCA) device versus standard ball-and-socket (BS) and ball-in-trough (BT) arthroplasty devices. The overall body of evidence from this group of tests supports the conclusion that the PCA device does control posture to a particular lordotic position, whereas BS and BT devices move freely through their ranges of motion.

Effect of arthroplasty design on cervical spine kinematics: analysis of the Bryan Disc, ProDisc-C, and Synergy Disc

Object

Cervical total disc replacement has emerged as a surgical option to preserve motion and potentially avoid adjacent-segment disease after anterior cervical discectomy and fusion. Recently, much attention has been directed at the ability of a given device to maintain and/or restore normal segmental alignment. Nonphysiological disc and segmental angulation could result in increased stresses transmitted to the facet joints and posterior elements, conflicting with the essence of arthroplasty and potentially leading to adjacent-segment disease. The goal of this study was to contrast device alignment and segmental kinematics provided by 3 different cervical disc prostheses.

Methods

Sixty patients were retrospectively analyzed and divided into 3 groups receiving the Bryan, ProDisc-C, or Synergy disc. Only single-level arthroplasty cases were included in the study. Lateral dynamic radiographs of the cervical spine were analyzed using quantitative motion analysis software (Medical Metrics, Inc.) to analyze the kinematics at the index level both preoperatively and postoperatively. Several parameters were noted, including range of motion, disc angles, shell angles, anterior and posterior disc heights, translation, and center of rotation. Preoperative and postoperative data were compared using the Student t-test with a significance level of p < 0.05.

Results

Postoperatively, all 3 disc groups maintained adequate range of motion at the implanted level. With respect to the shell angles, the Synergy disc demonstrated the least variability, maintaining 6° lordotic configuration between the device endplates. In the Bryan disc group, significant shell kyphosis developed postoperatively (p < 0.0001). Both ProDisc-C and Synergy discs significantly increased anterior and posterior disc heights (p < 0.0001). The Bryan and Synergy discs maintained the natural center of rotation, whereas significant anterior shift occurred with ProDisc-C.

Conclusions

The goal for motion preservation at the implanted level was achieved using all 3 devices. The Synergy disc was unique in its ability to alter device angulation by 6°. The Bryan disc demonstrated device endplate kyphosis. Both the Synergy disc and ProDisc-C increased disc space height.

Female genital TB and HIV co-infection

HIV-induced immunosuppression paves the way for several infections, tuberculosis being very common in our country. Female genital tuberculosis (FGTB), presenting as menstrual irregularities, is a diagnostic challenge in an adolescent female when these may be considered normal. The present case is of a young female who presented with menstrual irregularities, diagnosed subsequently as a case of genital tuberculosis. Microbiological relapse after anti-tubercular treatment of six months caused suspicion of a co-existing immunodeficiency and investigations revealed HIV co-infection; thus emphasizing the need of HIV testing in all patients of tuberculosis for timely diagnosis and treatment support thereafter.

Anterior cervical corpectomy and fusion accelerates degenerative disease at adjacent vertebral segments

BACKGROUND

Anterior cervical corpectomy provides the most direct and thorough surgical approach for anterior decompression when spinal cord compression is found directly behind the vertebral body. However, anterior cervical fusion has been shown to be associated with the development of new degenerative changes at levels immediately adjacent to the fused segments. Th e incidence of adjacent segment disease (ASD) following anterior cervical corpectomy has not been widely reported. We set out to determine the incidence of clinical ASD following anterior cervical corpectomy.

METHODS

We retrospectively reviewed all available medical charts and radiographic studies of all cases of anterior cervical corpectomy performed at the Barrow Neurological Institute over a 4-year period with a minimum 24-month follow-up. Factors assessed included the success of arthrodesis, the presence of degenerative changes on serial follow-up radiographs, and the development of new neurological symptoms.

RESULTS

Seventy-six patients met the criteria for inclusion: 54 had undergone a 1-level corpectomy, 18 underwent a 2-level corpectomy, and 4 underwent a 3- or 4-level corpectomy. Arthrodesis was performed with either allograft or autograft and anterior cervical plating. All patients achieved successful fusion. Follow-up was available for a minimum of 2 years in all cases, with a mean length of 3.6 years. Sixteen patients (21%) eventually developed radiological and clinical evidence of degenerative changes at adjacent levels. In 10 of 11 patients who developed clinical symptoms within 2 years, the changes represented progression of pre-existing, asymptomatic degenerative disease. Five patients developed degenerative changes more than 5 years after surgery; these were all associated with an unrelated new insult to the cervical spine such as trauma.

CONCLUSIONS

Anterior cervical corpectomy with fixation can accelerate degenerative changes identified preoperatively at adjacent, asymptomatic levels of the cervical spine.

LEVEL OF EVIDENCE

Retrospective cohort study (level 2b).

Recent outbreak of meningococcal meningitis--a microbiological study with brief review of literature

Meningococcal disease presents in various clinical forms, most common being meningitis and meningococcemia. A spurt of meningococcal cases was seen in medicine and pediatric wards of Dr. Ram Manohar Lohia Hospital during the recent outbreak from Dec 2005 - June 2006. These had presented either with the classical features of acute purulent meningitis or as fever with rash. The patients were investigated microbiologically for the causative organism which was identified as Neisseria meningitidis in 257 out of 531 cases (48.39%). The classic finding of gram negative diplococci on gram stain remained the mainstay of diagnosis. N. meningitidis isolates from culture were sensitive to all commonly used antibiotics.

Wrong-sided and wrong-level neurosurgery: a national survey

OBJECT

Perhaps the single greatest error that a surgeon hopes to avoid is operating at the wrong site. In this report, the authors describe the incidence and possible determinants of incorrect-site surgery (ICSS) among neurosurgeons.

METHODS

The authors asked neurosurgeons to complete an anonymous survey. These surgeons were asked to report the number of craniotomies and lumbar and cervical discectomies performed during the previous year, as well as whether ICSS had occurred. They were also asked detailed questions regarding the potential determinants of ICSS.

RESULTS

There was a 75% response rate and a 68% survey completion rate. Participating neurosurgeons performed 4695 lumbar and 2649 cervical discectomies, as well as 10,203 craniotomies. Based on this self-reporting, the incidence of wrong-level lumbar surgery was estimated to be 12.8 [corrected] occurrences per 10,000 operations. The ICSSs per 10,000 cervical discectomies and craniotomies were 7.6 [corrected] and 2.0, [corrected] respectively. Neurosurgeons recognized fatigue, unusual time pressure, and emergent operations as factors contributing to ICSS. For spine surgery, in particular, unusual patient anatomy and a failure to verify the operative site by radiography were also commonly reported contributors.

CONCLUSIONS

Neurosurgical ICSSs do occur, but are rare events. Although there are significant limitations to the survey-based methodology, the data suggest that the prevention of such errors will require neurosurgeons to recognize risk factors and increase the use of intraoperative imaging.

Dysembryoplastic neuroepithelial tumours: clinical, proliferative and apoptotic features

AIMS

Dysembryoplastic neuroepithelial tumours (DNTs) have been considered benign lesions characterised by a chronic, indolent clinical course. Previous studies have suggested that increased proliferation rates may be balanced by corresponding rates of apoptosis. The objective of this study was to determine whether a correlation exists between histological features and indices of proliferation/apoptosis.

METHODS

Fourteen consecutive surgical specimens meeting the histological criteria for DNT were retrospectively reviewed for evidence of aggressive histological features, including anaplasia, mitotic activity, and Ki67 labelling. Immunohistochemistry was performed semiquantitatively to evaluate and compare proliferation (Ki76) and apoptosis (TUNEL). The clinical course of the patients was also reviewed.

RESULTS

Atypical histological features were demonstrated in the glial component of select complex DNTs. TUNEL indices, however, had negligible correlation with proliferative indices. A balance between cell proliferation and apoptosis was not evident particularly in those cases displaying aggressive histological features.

CONCLUSIONS

While there is no clearly defined clinical or pathological pattern to indicate aggressive growth of DNTs, elevated proliferative indices coupled with atypical histological features in complex DNTs should be taken into consideration in determining the aggressiveness of surgical extirpation and follow-up until experience with these uncommon tumours is greater.