Posterior spinal surgery is associated with a significant amount of blood loss. The factors predisposing the patient to excessive bleeding-and therefore transfusion- are not well established nor is the effect of transfusion on the outcomes following spinal surgery. We had two goals in this study. First, we were to investigate any suspected risk factors of transfusion in posterior thoraco-lumbar fusion patients. Second, we wanted to observe the negative impact-if one existed- of transfusion on the outcomes of surgery

All adults undergoing posterior thoraco-lumbar spine fusion in our institution from May 2015 to May 2018 were included. Data collected included demographic data as well as BMI, preoperative hemoglobin, American Society of Anesthesiologists classification (ASA), delta Hemoglobin, estimated blood loss, incidence of transfusion, number of units transfused, number of levels fused, length of stay and re-admission within 30 days. The data was analyzed to correlate these variables with the frequency of transfusion and then to assess the association of adverse outcomes with transfusion.

125 patients were included in the study. Only 6 patients (4.8%) required re-admission within the first 30 days after discharge. Length of stay averaged 8.4 days (3–74). 18 patients (14.4%) required transfusion peri-operatively. When multiple variables were analyzed for any correlation, the number of levels fused, age and BMI had statistically significant correlation with the need for transfusion (P <0.005)

Patients undergoing posterior thoraco-lumbar fusion are more likely to require blood transfusion if they were older, over-weight & obese or had a multi-level fusion. Receiving blood transfusion is associated with increased complication rates.

Spondylolisthesis is common recognized spine pathology. A lot of studies targeted spondylolisthesis in the recent years, few of which have made a major influential impact on the clinical practice. To the extent our knowledge this is the first study to highlight and analyze the top 100 cited articles on spondylolisthesis through a systematic search strategy used previously in published studies in different medical specialty. The aim of this study is to identify the most cited studies on spondylolisthesis and report their impact in spine field.

Thomson Reuters Web of Science-Science Citation Index Expanded was searched using title-specific search “spondylolisthesis”. All studies published in English language between 1900 and 2019 were included with no restrictions. The top 100 cited articles were identified using “Times cited” arranging articles from high to low according to citation count. Further analysis was made to obtain the following items: Article title, author's name and specialty, country of origin, institution, journal of publication, year of publication, citations number, study design.

The citation count of the top 100 articles ranged from 69 to 584. All published between 1950 – 2016. Among 20 journals, Spine had the highest number of articles 47, with citation number of 5964 out of 13644. Second ranked was Journal of Bone and Joint Surgery with 16 articles and a total citation of 3187. In respect to the primary author's specialty, Orthopedic surgeons contributed to the majority of top 100 list with 82 articles, Neurosurgery was the second specialty with 10 articles. United states had produced more than half of the list by 59 articles. England was the second country with 7 articles. Surgical management of lumbar spondylolisthesis was the most common discussed topic.

This article identifies the top 100 influential papers on spondylolisthesis and recognizes an important aspect of knowledge evolution served by leading researchers as they guide today's clinical decision making in spondylolisthesis.