Spine – Relevant articles in 2016

Vol 1 | Issue 1 |  July – Dec 2016 | Page 48-52 | Arvind G Kulkarni

Authors: Arvind G Kulkarni [1].

[1] Mumbai Spine Scoliosis and Disc Replacement Centre, Bombay Hospital and Medical Research Centre, Mumbai, India.

Address of Correspondence
Dr Arvind G Kulkarni,
Mumbai Spine Scoliosis & Disc Replacement Centre,
Bombay Hospital &Medical Research Centre,
Mumbai, India.
E-mail: drarvindspines@gmail.com.

Mumbai is considered the Mecca for Spine Surgery. Many legends and centers have contributed immensely to the development of spine as a distinct specialty in Mumbai. Fittingly, this initial issue of the Bombay Orthopaedic Society edited by the illustrious Dr Nicholas Antao has delegated sumptuous space to literature on spine and spinal disorders. A journey through the past year’s high impact factor- journals like The Spine Journal, Spine, JNS-Spine, European Spine Journal, Journal of Spinal Disorders and Techniques and the Global Spine journal reveals that the perspectives may change with time but the basics still remain the same. There has been an increasing talk among researchers about adjacent segment degeneration, clinically significant adjacent segment disease, issue of post-operative dysphagia after anterior cervical surgeries, importance of natural history in spinal disorders, about the ever increasing scope of minimally invasive surgeries from the basic decompression to deformity corrections and the accuracy of pedicle screw insertion. This synopsis ends up with summarizing some significant contributions by Indian authors to the literature this year.

Adjacent segment Degeneration and Clinically significant adjacent segment Disease
Since fusion procedures have become so frequent the entities called ‘adjacent segment degeneration (ASD)’ and ‘adjacent segment disease (ASDis)’ are becoming issues of concern. Motion preservation surgeries, especially ‘artificial disc replacement’ was proposed as an alternative to fusion that had the potential to minimize the incidence of ASD. Does it really do so in the long run is a million dollar question? Although there is no Level I evidence, in a meta analysis involving 1474 patients, Pan A and colleagues’ [1] have evaluated the efficacy of motion preservation procedures to prevent ASD or ASDis compared to fusion procedures in lumbar spine. They indicated that the prevalence of ASD and ASDis and reoperation rate on the adjacent level were lower in motion preservation procedures group than in the fusion group. More over shorter stay in hospital was found in motion preservation group and no difference in terms of operation time, blood loss, and VAS and ODI improvement between the two groups. Another interesting paper on ASD throws light on the risk factors associated with the same. Heo Y et al [2] in their 10 years follow-up study of 401 patients where fusion surgeries were performed for spondylolysthesis at L4-5 or L4-5-S1 focused on risk factors that affected clinically symptomatic ASD (CASD). They evaluated six significant factors affecting CASD development. Among these risk factors, facet degeneration, isthmic-type spondylolisthesis, and the type of fusion show higher hazard ratios and seem to be clinically more relevant than the other three factors (age, overall lordosis, and segmental lordosis).

Minimally invasive decompression in lumbar degenerative spondylolisthesis
The debate on the type of surgical procedure for degenerative spondylolisthesis goes on forever. Since conventional procedures for decompression involving surgical invasion of facet joints and surrounding soft tissue could increase instability and exacerbate clinical symptoms, decompression combined with fusion is generally recommended. Gen Mori et al [3] evaluated the outcomes in cases of lumbar degenerative spondylolisthesis at a follow-up of 5 years after treatment with minimally invasive decompression with examination of pre- and postoperative slippage, intervertebral disc changes, and clinical results. The hypothesis that this study relied on is the natural history of LDS and the preservation of anatomical structures in MED. The authors concluded that if minimally invasive decompression can be performed to treat LDS, it is believed that preoperative percentage slip and intervertebral disc degeneration do not have to be included in the appropriateness criteria for fusion.

Understanding Pedicle Screw misplacement
Due to better primary stability and repositioning options, pedicle screws are increasingly used during posterior stabilization of the cervical spine. However, the serious risks generally associated with the insertion of screws in the cervical spine remain. Bredow J et al [4] conducted a study to examine the accuracy of pedicle screw insertion with the use of 3D fluoroscopy navigation systems. Data of 64 patients were collected during and after screw implantation (axial and sub axial) in the cervical spine. 207 screws were implanted from C1 to C7 and analyzed for placement accuracy according to post operative CT scans and following the modified Gertzbein and Robbins classification. It was concluded that axial and sub axial screws can be inserted with a high grade of accuracy using 3D fluoroscopy-based navigation systems. Nevertheless, while this useful innovation helps to minimize the risks of misplacement, the surgery is still a challenge, as arising complications remain severe. The accuracy rate of pedicle screw (PS) placement varies from 85% to 95% in the literature. This demonstrates technical ability but does not represent the impact of screw misplacement on individual patients. A retrospective study conducted by Sarwahi V et al [5] quantifies the rate of screw misplacement on a per-patient basis to highlight its effect on potential morbidity. Of the 2724 screws placed in 127 patients, a total of 2396 screws were accurately placed (87.96%). A total of 247 screws (9.07%) were benign misplaced, 52 (1.91%) were intermediate misplaced, and 29 (1.06%) were considered in screw at risk (SAR) group. Per-patient analysis showed 23 (18.11%) of patients had all screws accurately placed (AP), thirty-five (27.56%) had IMP and 18 (14.17%) had SAR. Per-patient analysis reveals more concerning numbers toward screw misplacement. With increasing pedicle screw usage, the number of patients with misplaced screws will likely increase proportionally. Better strategies need to be devised for evaluation of screw placement, including establishment of a national database of deformity surgery, use of intra-operative image guidance, and reevaluation of postoperative low-dose CT imaging.

Oswestry Disability Index [ODI]
ODI has long been used to study the outcomes of patients suffering from lumbar degenerative disorders. A significant reduction in ODI scores is an index of patient’s satisfaction and reduction of disability, although there has not been quantification for the same as to what value indicates as being significant. Van Hooff ML et al [6] suggested an ODI score ≤22 indicates the achievement of an acceptable symptom state and can hence be used as a criterion of treatment success alongside the commonly used change score measures. At the individual level, the threshold could be used to indicate whether or not a patient with a lumbar spine disorder is a “responder” after elective surgery.

Knee-up test
Post- operative neurological deficit is one of the complications of spine surgery that is most dreadful for the surgeon as well as the patient. Efforts have been put since years to reduce this complication. One of the simplest ways to detect if such an event has occurred before extubation of the patient is a Knee- Up test. Yugue et al [7] conducted a prospective study of 521 patients where the patient’s knee is passively lifted up and the patient is able to maintain this position in both legs, the result is negative, whereas when the patient is unable to maintain the knee in an upright position for one or both legs, the result is positive. The sensitivity, specificity, positive predictive value, and negative predictive value were 88.9, 99.8, 94.1, and 99.6, respectively.

Parkinson’s disease (PD) and cervical myelopathy
Parkinson’s disease (PD) is a common movement disorder in elderly patients and co-existence with cervical myelopathy complicates the situation. There have been questions about the efficacy of surgery in such patients and thus providing them with a better quality of life. Xiao R et al (The Spine Aug 2016) conducted first study to characterize QOL outcomes following cervical decompression and found significant reduction in pain-related disability was observed following decompression. However, PD predicted diminished improvement in overall QOL measured by the EQ-5D.

Novel approach for lumbar interbody fusion
Lumbar interbody fusion is being long used as the method of choice in lumbar degenerative disorders and is most commonly done through posterior approaches (PLIF and TLIF). The direct anterior approach requires mobilization of the great vessels to access the intervertebral disc spaces cranial to L5/S1. Molloy et al [9] came up with a novel extensile anterolateral retroperitoneal approach for lumbar interbody fusion from L1 to S1 which is safe, muscle-splitting, psoas-preserving, one-incision approach and thus revolutionize interbody fusion technique.

Glass ceramics spacers
Constant efforts are being made to improve the fusion rates in patients suffering from lumbar degenerative disorders. The most recent advent is the CaO-SiO2-P2O5-B2O3 glass ceramics spacer. Lee JH et al [10] found that ceramics spacer showed a similar fusion rates and clinical outcomes compared with titanium cage however, the bone fusion area directly attached to the end plate was significantly higher in the bioactive glass ceramics group than in the titanium group.

Anterior Cervical surgeries and the role of steroids
Dysphagia is a common post-operative symptom for patients undergoing anterior cervical spine procedures. Siasios I et al [11] studied the current literature regarding the effect of steroid administration in dysphagia after anterior cervical spine procedures through a literature search. Steroid administration protocol involved dexamethasone in few, Methylprednisolone in others. In four studies, steroids were applied intra-venous, while in one study, locally in the retropharyngeal space. Short-term dysphagia and prevertebral soft tissue swelling (PSTS) were diminished by steroid administration, according to the results of two studies. In one study, prevertebral soft tissue edema was not affected by the steroid usage. Furthermore, short-term osseous fusion rate was impaired by the steroid administration, according to the findings of one study. After a review of 44 patients undergoing multilevel (2-, 3-, 4-level) ACDF, 22 of which received RP steroid, Koreckij TD et al [12] noted a trend toward decreased PSTS on initial postoperative radiographs, but was no longer evident at 6 weeks. NDI, although improved from pre-operative scores, failed to demonstrate significant differences between groups. Locally delivered methyl prednisone did not result in increased rates of short-term postoperative complications

Top 100 cited article in cervical spine surgery
Cervical spine surgery is a rapidly evolving and challenging subspecialty that owes its advancements to many individuals and their pioneering works that have shaped the way we practice modern cervical spine surgery today. A study conducted by Branko Skovrlj et al [13] identifies the authors and 100 topics that made the greatest impact in the field of cervical spine surgery over the course of the last century and the beginning of this century. The top article was cited 826 times; the 100th article, 133 times; and the mean number of citations for the top 100 articles were 203.6. The oldest article was by Rogers published in 1957. The newest article was published in 2009 by Murrey et al. Eighty-three percent of the top 100 cited articles were published after 1980, with the 1990s producing the largest number of highly cited articles (35%). The top 100 articles were published in 18 journals, with the top three journals publishing 72% of the articles. The top journal was Spine with 39 articles followed by the Journal of Bone and Joint Surgery American Volume with 20 articles and the Journal of Neurosurgery with 13 articles. The three most popular categories were cervical spinal fusion with 17 articles, surgical complications with 9 articles, and biomechanics of the cervical spine with 9 articles. Eighty-six first authors contributed to the top 100 articles. Only three authors were credited with three or more publications and only one author, Abumi, had four publications in the top 100. The top articles originated from nine different countries, with the United States (65%) being the most prolific. There were 61 institutions responsible for the top-cited articles with Hokkaido University in Sapporo, Japan contributing the most articles with five publications in the top 100.

Prediction of posterior ligamentous complex injury in thoracolumbar fractures using non-MRI imaging techniques.
Rajasekaran S and colleagues [14] formulated a radiological index based on plain radiographs and computer tomography (CT) to reliably detect posterior ligamentous complex (PLC) injury without need for MRI. They assessed thoracolumbar fractures with doubtful PLC with MRI, CT and radiographs. PLC injury was assessed with the following radiological parameters: superior-inferior end plate angle (SIEA), vertebral body height (BH), local kyphosis (LK), inter-spinous distance (ISD) and inter-pedicular distance (IPD) and correlated with MRI findings of PLC injury. They proposed that on plain radiographs the presence of LK greater than 20° and ISD difference greater than 2 mm can predict PLC injury. These guidelines may be utilized in the emergency room especially when the associated cost, availability and time delay in performing MRI are a concern.

Irreducible AAD
SK Srivastava et al [14] demonstrated an excellent technique for a difficult problem. The study reinforces the safety and efficacy anterior release for reduction of IAAD. They concluded that anterior release followed by instrumented posterior fusion is a safe and effective modality of treatment for IAAD associated with basilar invagination. This opens up a new avenue for this difficult problem.

Clinical efficacy of tapered rods in posterior cervicothoracic instrumentation
The cervicothoracic spine is a junctional area with complex biomechanics. Kulkarni AG et al [15] analyzed the efficacy of tapered rod system in clinical scenarios in the short term. In their study no biomechanical failure occurred in any of the 14 patients and intraoperative complications were noted in none. This is the first study on the efficacy of tapered rods and demonstrates that tapered rods are an excellent and a viable option to connect screws to stabilize cervicothoracic junction in the short term.


1. Pan A, Hai Y, Yang J, Zhou L, Chen X, Guo H. Adjacent segment degeneration after lumbar spinal fusion compared with motion-preservation procedures: a meta-analysis. Eur Spine J. 2016 May;25(5):1522-32.
2. Heo Y, Park JH, Seong HY, Lee YS, Jeon SR, Rhim SC, Roh SW. Symptomatic adjacent segment degeneration at the L3-4 level after fusion surgery at the L4-5 level: evaluation of the risk factors and 10-year incidence. Eur Spine J. 2015 Nov;24(11):2474-80.
3. Mori G, Mikami Y, Arai Y, Ikeda T, Nagae M, Tonomura H, Takatori R, Sawada K, Fujiwara H, Kubo T. Outcomes in cases of lumbar degenerative spondylolisthesis more than 5 years after treatment with minimally invasive decompression: examination of pre- and postoperative slippage, intervertebral disc changes, and clinical results. J Neurosurg Spine. 2016 Mar;24(3):367-74.
4. Bredow J, Oppermann J, Kraus B, Schiller P, Schiffer G, Sobottke R, Eysel P, Koy T. The accuracy of 3D fluoroscopy-navigated screw insertion in the upper and subaxial cervical spine. Eur Spine J. 2015 Dec;24(12):2967-76.
5. Sarwahi V, Wendolowski SF, Gecelter RC, Amaral T, Lo Y, Wollowick AL, Thornhill B. Are We Underestimating the Significance of Pedicle Screw Misplacement? Spine (Phila Pa 1976). 2016 May;41(9):E548-55.
6. van Hooff ML, Mannion AF, Staub LP, Ostelo RW, Fairbank JC. Determination of the Oswestry Disability Index score equivalent to a “satisfactory symptom state” in patients undergoing surgery for degenerative disorders of the lumbar spine-a Spine Tango registry-based study. Spine J. 2016 Oct;16(10):1221-1230.
7. Yugué I, Okada S, Masuda M, Ueta T, Maeda T, Shiba K. “Knee-up test” for easy detection of postoperative motor deficits following spinal surgery. Spine J. 2016 Aug 9. pii: S1529-9430(16)30866-X.
8. Xiao R, Miller JA, Lubelski D, Alberts JL, Mroz TE, Benzel EC, Krishnaney AA, Machado AG. Quality of life outcomes following cervical decompression for coexisting Parkinson’s disease and cervical spondylotic myelopathy. Spine J. 2016 Nov;16(11):1358-1366.
9. Molloy S, Butler JS, Benton A, Malhotra K, Selvadurai S, Agu O. A new extensile anterolateral retroperitoneal approach for lumbar interbody fusion from L1 to S1: a prospective series with clinical outcomes. Spine J. 2016 Jun;16(6):786-91.
10. Lee JH, Kong CB, Yang JJ, Shim HJ, Koo KH, Kim J, Lee CK, Chang BS. Comparison of fusion rate and clinical results between CaO-SiO(2)-P(2)O(5)-B(2)O(3) bioactive glass ceramics spacer with titanium cages in posterior lumbar interbody fusion. Spine J. 2016 Nov;16(11):1367-1376.
11. Siasios ID, Dimopoulos VG, Fountas KN. Local steroids and dysphagia in anterior cervical discectomy and fusion-does the employment of rhBMP-2 make their use a necessity? J Spine Surg. 2016 Sep;2(3):234-236.
12. Koreckij TD, Davidson AA, Baker KC, Park DK. Retropharyngeal Steroids and Dysphagia Following Multilevel Anterior Cervical Surgery. Spine (Phila Pa 1976). 2016 May;41(9):E530-4
13. Skovrlj B, Steinberger J, Guzman JZ, Overley SC, Qureshi SA, Caridi JM, Cho SK. The 100 Most Influential Articles in Cervical Spine Surgery. Global Spine J. 2016 Feb;6(1):69-79.
14. Rajasekaran S, Maheswaran A, Aiyer SN, Kanna R, Dumpa SR, Shetty AP. Prediction of posterior ligamentous complex injury in thoracolumbar fractures using non-MRI imaging techniques. Int Orthop. 2016 Jun;40(6):1075-81.
15. Srivastava SK, Aggarwal RA, Nemade PS, Bhosale SK. Single-stage anterior release and posterior instrumented fusion for irreducible atlantoaxial dislocation with basilar invagination. Spine J. 2016 Jan 1;16(1):1-9.
15. Kulkarni AG, Dhruv AN, Bassi AJ. Posterior Cervicothoracic Instrumentation: Testing the clinical efficacy of Tapered Rods (Dual-Diameter Rods). J Spinal Disord Tech. 2015 Dec;28(10):382-8.

How to Cite this article: Kulkarni AG. Spine – Relevant articles in 2016. Journal of Clinical Orthopaedics July – Dec 2016; 1(1):48-52.

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