Vibhu Krishnan Viswanathan

Clinical and Radiologic Outcomes After Fenestration and Partial Wall Excision of Idiopathic Intradural Spinal Arachnoid Cysts Presenting with Myelopathy

BACKGROUNDnIntradural spinal arachnoid cysts (ISACs) with associated neurologic deficits are encountered infrequently. Various management strategies have been proposed with minimal data on comparative outcomes.nnnOBJECTIVEnWe describe the clinical and radiologic presentation as well as the outcomes of 14 surgically managed patients who presented with an ISAC and associated myelopathy.nnnMETHODSnWe retrospectively reviewed the clinical course of consecutive patients presenting with neurologic deficits associated with idiopathic ISACs at our institution. The diagnoses were based on preoperative magnetic resonance imaging studies followed by intraoperative and histopathological confirmation.nnnRESULTSnA total of 14 consecutive patients with ISACs (1 cervicothoracic, 12 thoracic, and 1 thoracolumbar) and associated myelopathy were identified. Syringomyelia was noted in 8 patients. All ISACs were treated with cyst fenestration and partial wall resection through a posterior approach. Preoperative neurologic symptoms were noted to be stable or improved in all patients starting at 6-week postoperative follow-up. The median (interquartile range) preoperative mJOA score was 13 (12.0-14.8), whereas the postoperative median score at a mean follow-up of 22 months (range 6-50 months) was 16 (14.0-17.0), which represents a median improvement (ΔmJOA) of 2.0 (1.3-3.0) (P < 0.001). Comparison of ΔmJOA scores between cases without and with associated syrinxes did not reveal a significant difference (P = 0.23). Postoperative magnetic resonance imaging scans revealed spinal cord re-expansion at the level of the ISAC in all cases and either complete or partial syrinx resolution in 7 of 8 cases.nnnCONCLUSIONSnEarly treatment with fenestration and partial wall resection allows for cord decompression, syrinx resolution, and gradual resolution of myelopathic symptoms in most cases.

Comparative Utility of Dynamic and Static Imaging in the Management of Lumbar Spondylolisthesis

OBJECTIVEnSegmental instability traditionally is investigated with flexion and extension (F/E) radiographs. We sought to determine whether motion between upright and supine (U/S) views can serve as an alternative sensitive diagnostic tool that predicts similar outcomes.nnnMETHODSnAmbispective collection of data was performed for 222 consecutive patients who underwent transforaminal lumbar interbody fusion. Patients were divided into either group 1 (≥3 mm spondylolisthesis difference between F/E radiographs) or group 2 (≥3 mm spondylolisthesis difference between U/S imaging and otherwise not meeting group 1 criteria).nnnRESULTSnIn total, 77 patients metxa0all inclusion/exclusion criteria. Patients in group 1 (nxa0= 26) and group 2 (nxa0= 51) did not differ with respect to key demographic criteria. Average clinical follow-up for groups 1 and 2 were 31.8 and 35.6 months (Pxa0= 0.43). Average spondylolisthesis was 8.1 mm and 8.0 mm for groups 1 and 2 (Pxa0= 0.93). The incidence of facet joint hyperintensity on T2-weighted magnetic resonance imaging and average maximal facet joint widening (P > 0.2) did not differ between groups. Average F/E slip change was 5.0 mm for group 1 and average U/S slip change was 5.2 mm for group 2. For both groups, Numeric Rating Scale Back Pain and Numeric Rating Scale Leg Pain, Oswestry Disability Index v2.1a, and Short-Form 36 RAND (P < 0.02) improved significantly after surgery. Furthermore, ΔNumeric Rating Scale Back Pain, ΔNumeric Rating Scale Leg Pain, ΔOswestry Disability Index v2.1a, and ΔShort-Form 36 RAND (P > 0.2) were not significantly different between groups.nnnCONCLUSIONSnNo differences in outcomes were noted between patients based on either imaging criteria. These data suggest that static U/S imaging may identify a distinct group of patients who may benefit from transforaminal lumbar interbody fusion surgery.

Prospective assessment of the safety and early outcomes of sublaminar band placement for the prevention of proximal junctional kyphosis

OBJECTIVE Proximal junctional kyphosis (PJK) can progress to proximal junctional failure (PJF), a widely recognized early and serious complication of multisegment spinal instrumentation for the treatment of adult spinal deformity (ASD). Sublaminar band placement has been suggested as a possible technique to prevent PJK and PJF but carries the theoretical possibility of a paradoxical increase in these complications as a result of the required muscle dissection and posterior ligamentous disruption. In this study, the authors prospectively assess the safety as well as the early clinical and radiological outcomes of sublaminar band insertion at the upper instrumented vertebra (UIV) plus 1 level (UIV+1). METHODS Between August 2015 and February 2017, 40 consecutive patients underwent either upper (T2-4) or lower (T8-10) thoracic sublaminar band placement at the UIV+1 during long-segment thoracolumbar arthrodesis surgery. Outcome measures were prospectively collected and uploaded to a web-based REDCap database specifically designed to include demographic, clinical, and radiological data. All patients underwent clinical assessment, as well as radiological assessment with anteroposterior and lateral 36-inch whole-spine standing radiographs both pre- and postoperatively. RESULTS Forty patients (24 women and 16 men) were included in this study. Median age at surgery was 64.0 years with an IQR of 57.7-70.0 years. Median follow-up was 12 months (IQR 6-15 months). Three procedure-related complications were noted, including 2 intraoperative cerebrospinal spinal fluid leaks and 1 transient neurological deficit. Median visual analog scale (VAS) scores for back pain significantly improved after surgery (preoperatively: 8.0, IQR 6.0-10.0; 1-year follow-up: 2.0, IQR 0.0-6.0; p = 0.001). Median Oswestry Disability Index (version 2.1a) scores also significantly improved after surgery (preoperatively: 56.0, IQR 45.0-64.0; 1-year follow-up: 46.0, IQR 22.2-54.0; p < 0.001). Sagittal vertical axis (preoperatively: 9.0 cm, IQR 5.3-11.6 cm; final follow-up: 4.7 cm, IQR 2.0-6.6 cm; p < 0.001), pelvic incidence-lumbar lordosis mismatch (24.7°, IQR 11.2°-31.2°; 7.7°, IQR -1.2° to 19.5°; p < 0.001), and pelvic tilt (28.7°, IQR 20.4°-32.6°; 17.1°, IQR 10.8°-25.2°; p < 0.001) were all improved at the final follow-up. While proximal junctional (PJ) Cobb angles increased overall at the final follow-up (preoperatively: 4.2°, IQR 1.9°-7.4°; final follow-up: 8.0°, IQR 5.8°-10.3°; p = 0.002), the significant increase was primarily noted starting at the immediate postoperative time point (7.2°, IQR 4.4°-11.8°; p = 0.001) and not beyond. Three patients (7.5%) developed radiological PJK (mean ΔPJ Cobb 15.5°), while there were no instances of PJF in this cohort. CONCLUSIONS Sublaminar band placement at the UIV+1 during long-segment thoracolumbar instrumented arthrodesis is relatively safe and is not associated with an increased rate of PJK. Moreover, no subjects developed PJF. Prospective large-scale and long-term analysis is needed to define the potential benefit of sublaminar bands in reducing the incidence of PJK and PJF following surgery for ASD. Clinical trial registration no.: NCT02411799 (clinicaltrials.gov).

Surgical management of adult type 1 split cord malformation. Report of two cases with literature review

Split cord malformation (SCM) is a rare form of spinal dysraphism wherein the spinal cord is divided longitudinally into two distinct hemicords. Surgery is usually performed in children while management in adults, who rarely manifest symptoms, remains controversial. Both expectant management and prophylactic surgery have been variously advocated. The present article describes our experience in two adult patients with predominant pain-related complaints who underwent surgical excision of type 1 SCM lesions. A comprehensive review of the literature on SCM in adults is also provided. While pain, disability, and quality of life scores improved in these two patients, further larger studies will be required to define the role of surgery in adults with type 1 SCM and a pain-dominant presentation.

Comparison of Three Different Options for C7 Posterior Vertebral Anchor in the Indian Population—Lateral Mass, Pedicle, and Lamina: A Computed Tomography-Based Morphometric Analysis

Study Design Radiological cohort study. Purpose The options of posteriorly stabilizing C7 vertebra include using lateral mass, pedicle or lamina, as bony anchors. The current study is a computed tomography (CT)-based morphometric analysis of C7 vertebra of 100 Indian patients and discusses the feasibility of these different techniques. Overview of Literature C7 is a peculiar vertebra with unique anatomy, which poses challenges for each of these fixation modalities. There are no reports available in the literature, which discuss and compare the feasibility of diverse posterior C7 fixation techniques in Indian population. Methods We included 100 consecutive cervical spine CT scans of Indian patients performed between July 2016 and September 2016. We excluded CT scans with any significant congenital anomaly or other pathological lesions of C7 and patients with non-Indian ethnicity. Regarding screw placement, we assessed and studied various dimensions of the C7 lateral mass, pedicles, and laminae in relevant sections. Results The mean age of our patients was 49.5±16.1 years. We included 56 male and 44 female patients. The mean anteroposterior and mediolateral dimensions of the lateral mass were 11.38±1.76 and 12.91±1.82 mm, respectively. The mean length of the lateral mass screw (Magerl technique) was 12.17±1.9 mm; 92% of patients could accommodate a lateral mass screw at least 10-mm long (unicortical), whereas 48% could accommodate a screw (unicortical) longer than 12 mm. Foramen transversarium was found in 30.5% of lateral masses. The mean outer and inner cortical widths of the pedicles were 6.5±0.71 mm and 3.72±0.61 mm, respectively. Approximately 58% of pedicles could accommodate 3.5-mm screws (based on the inner cortical pedicle width). The outer cortical and inner cortical widths of the laminae were 6.21±1.2 mm and 3.23±0.9 mm, respectively. Subsequently, 37% of the laminae could accommodate 3.5-mm screws. The mean angle of intralaminar screw trajectory was 50.7°±5.1°, and the mean length of the intralaminar screw was 32.6±3.05 mm. In addition, 96.4% and 60.7% of male patients could accommodate lateral mass screws longer than 10 mm and 12 mm, respectively. However, only 86.4% and 31.8% of female patients could accommodate 10- and 12-mm long lateral mass screws, respectively. Furthermore, 75% of male patients and 36% of female patients had pedicles that could accommodate 3.5-mm diameter screws, and 48.2% of male patients had laminae that could accommodate 3.5-mm screws; however, only 22.7% of female patients could accommodate 3.5-mm laminar screws. Conclusions Based on our CT-guided morphometric analysis, 92% and 48% of Indian patients could accommodate at least 10- and 12-mm long lateral mass screws, and 58% of pedicles and 37% of laminae could accommodate 3.5-mm screws. Thus, lateral mass screws (between 10- and 12-mm long) seem to be the safest feasible option for C7 fixation. In case of the need for an alternative mode of stabilization (pedicle or intralaminar screw), particularly in female patients, careful preoperative planning with a CT scan is of utmost importance.

Factors Affecting Early and 1-Year Motor Recovery Following Lumbar Microdiscectomy in Patients with Lumbar Disc Herniation: A Prospective Cohort Review

Study Design Prospective cohort study. Purpose The study was aimed at evaluating clinicoradiological factors affecting recovery of neurological deficits in cases of lumbar disc herniation (LDH) treated by lumbar microdiscectomy. Overview of Literature The majority of the available literature on neurological recovery following neurodeficit is limited to retrospective series. The literature is currently limited regarding variables that can help predict the recovery of neurodeficits following LDH. Methods A prospective analysis was performed on 70 consecutive patients who underwent lumbar microdiscectomy (L1–2 to L5–S1) owing to neurological deficits due to LDH. Patients with motor power ≤3/5 in L2–S1 myotomes were considered for analysis. Follow-up was performed at 2, 6, and 12 months to note recovery of motor deficits. Clinicoradiological parameters were compared between the recovered and nonrecovered groups. Results A total of 65 patients were available at the final follow-up: 41 (63%) had completely recovered by 2 months; four showed delayed recovery at the 6-month follow-up; and 20 (30.7%) showed no recovery at 1 year. Clinicoradiological factors, including diabetes, complete initial deficit, areflexia, multilevel disc prolapse, longer duration since initial symptoms, and ≥2 previous symptomatic episodes were associated with a significant risk of poorer recovery (p<0.05 for all). Age, sex, occupation, smoking, level/type or location of disc herniation, primary canal stenosis, disc fragment dimensions, precipitating factors, bladder involvement, bilaterality of symptoms, and the presence or absence of anal reflex did not affect neurological recovery (p>0.05 for all). Diabetes mellitus (p=0.033) and complete initial motor deficit (p=0.028) were significantly associated with delayed recovery in the multivariate analysis. Conclusions The overall neurological recovery rate in our study was 69%. Diabetes mellitus (p=0.033) and complete initial motor deficit were associated with delayed motor recovery.

Letter to the Editor: Long-term Outcomes of In Situ Fusion for Treating Dysplastic Spondylolisthesis

Copyright C 2017 by Korean Society of Spine Surgery This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Asian Spine Journal • pISSN 1976-1902 eISSN 1976-7846 • www.asianspinejournal.org Received May 5, 2017; Accepted May 8, 2017 Corresponding author: Vibhu Krishnan Viswanathan Department of Neurological Surgery The Ohio State University, Columbus, OH 43202, USA Tel: +16143023859, E-mail: drvibu007@gmail.com

Letter: Comparison of Posterior Lumbar Interbody Fusion and Posterolateral Lumbar Fusion in Monosegmental Vacuum Phenomenon within an Intervertebral Disc

We read with great interest the article by An et al. [1] titled Comparison of Posterior Lumbar Interbody Fusion and Posterolateral Lumbar Fusion in Monosegmental Vacuum Phenomenon within an Intervertebral Disc. The authors analyzed retrospectively collected data involving 84 patients and described their experience with postero-lateral and posterior lumbar inter-vertebral fusion in situations of mono-segmental inter-vertebral disc vacuum. This issue remains controversial and the authors description is definitely an eye-opener to the readers. It is a well-written article and has fore-grounded some of the major concerns of the contemporary medical fraternity. We do have some queries to the authors regarding this study: