Finite Element Analysis Comparing the Biomechanical Parameters in Multilevel Posterior Cervical Instrumentation Model Involving Lateral Mass Screw versus Transpedicular Screw Fixation at the C7 Vertebra.

STUDY DESIGN: Basic research. PURPOSE: This finite element (FE) analysis (FEA) aimed to compare the biomechanical parameters in multilevel posterior cervical fixation with the C7 vertebra instrumented by two techniques: lateral mass screw (LMS) vs. transpedicular screw (TPS). OVERVIEW OF LITERATURE: Very few studies have compared the biomechanics of different multilevel posterior cervical fixation constructs. METHODS: Four FE models of multilevel posterior cervical fixation were created and tested by FEA in various permutations and combinations. Generic differences in fixation were determined, and the following parameters were assessed: (1) maximum moment at failure, (2) maximum angulation at failure, (3) maximum stress at failure, (4) point of failure, (5) intervertebral disc stress, and (6) influence of adding a C2 pars screw to the multilevel construct. RESULTS: The maximum moment at failure was higher in the LMS fixation group than in the TPS group. The maximum angulation in flexion allowed by LMS was higher than that by TPS. The maximum strain at failure was higher in the LMS group than in the TPS group. The maximum stress endured before failure was higher in the TPS group than in the LMS group. Intervertebral stress levels at C6-C7 and C7-T1 intervertebral discs were higher in the LMS group than in the TPS group. For both models where C2 fixation was performed, lower von Mises stress was recorded at the C2-C3 intervertebral disc level. CONCLUSIONS: Ending a multilevel posterior cervical fixation construct with TPS fixation rather than LMS fixation at the C7 vertebra provides a stiff and more constrained construct system, with higher stress endurance to compressive force. The constraint and durability of the construct can be further enhanced by adding a C2 pars screw in the fixation system.

"Spine Surgery Checklist": A Step towards Perfection through Protocols.

STUDY DESIGN: A retrospective study. PURPOSE: This study aimed to evaluate the effectiveness of a novel checklist that was designed specifically for the "spine-surgerysubspecialty" to reduce the incidence of some common preventable human errors and major perioperative complications in spine surgery. OVERVIEW OF LITERATURE: We propose a unique spine surgery-specific checklist that recognizes the risk factors, anticipates the possible human errors, and thus helps in preventing these errors. This checklist is associated with increased patient safety awareness, improved communication (keeps everyone updated regarding their responsibilities), reduction in the surgical claims, and reduction in the number of postoperative complications, including mortality. METHODS: This retrospective pilot study was performed at single center on 858 spine surgery patients. The patients were divided into the following two groups: the study group (after implementation of the checklist [2016-2017]) and the control group (before the implementation of the checklist [2015-2016]). The incidence of common preventable human errors and major perioperative complications in spine surgeries were recorded and compared between the two groups. RESULTS: The prevalence of wrong-level surgeries was 0%, and the overall prevalence of the preventable errors was 1.63% (7/428). The rate of adverse, near-miss, and no-harm events was 0.23% (1/428), 0.70% (3/428) and 0.70% (3/428), respectively. The preoperative, intraoperative, and postoperative errors were 0.70% (3/428), 0.23% (1/428), and 0.70 (3/428), respectively. The reoperation rate related to preventable errors reduced after the checklist was used. There were significant differences in the total preventable errors related to complications, such as infections, prolonged hospital stays, and unplanned hospital readmission/revision surgeries (p=0.001). CONCLUSIONS: The authors propose the first-of-its kind spine surgery-specific checklist that is comprehensive and involves perioperative parameters. The checklist is easy to use, safe, and effective for reducing the unforgiving errors and perioperative complications. However, its broader implementation would require validation in large, multi-center, randomized control studies.

Baroreflex Failure After Anterior Cervical Discectomy and Fusion: A Case Report.

CASE: A 58-year-old man underwent anterior cervical discectomy and fusion (ACDF) for the treatment of cervical spondylotic myelopathy. Immediately after surgery, the patient experienced elevated blood pressure with a fall in oxygen saturation which prevented extubation. He required admission to the critical care unit and was diagnosed with baroreflex failure syndrome (BFS). He was managed with a 4-drug medical regimen and stabilized by the second postoperative day. CONCLUSION: BFS should be considered in the setting of sudden sharp elevation in blood pressure after ACDF. Early diagnosis and initiation of appropriate pharmacotherapy may reduce patient morbidity and mortality.

Management of spondylolisthesis using MIS techniques: Recent advances.

The authors discuss the recent advances in the understanding and management of spondylolisthesis. The two most common kinds of spondylolisthesis - Degenerative and Spondylolytic types have been elaborated in this paper, with the understanding that similar management principles can be applied to the other lesser common varieties. The impetus has been on application of minimally invasive techniques in the treatment as well as renewed interest in stand-alone decompression in degenerative spondylolisthesis.

Nasogastric tube in anterior cervical spine surgery, is it necessary?

BACKGROUND: The aim of this article was to verify the utility of nasogastric (NG) tube in primary anterior cervical surgeries. Palpating and identifying the NG tube introduced during induction is one of the ways of preventing esophageal injuries during surgery. It may also be used as a conduit for postoperative feeding. However, the use of NG tube is not without complications. Esophageal perforation is one of them, with an incidence of 0.3%. MATERIALS AND METHODS: A retrospective observational study was performed of patients who underwent a primary anterior cervical spine surgery from January 2007 to July 2017 by a single surgeon. The indications were degenerative, trauma, infection, and neoplasia. NG tube was avoided in all cases. The patients were followed for 6 months. RESULTS: Our study included 356 patients (201 males and 155 females), with a mean age of 43.6 years (18-92 years) and a mean follow-up of 6 months. We had only one case of esophageal perforation (0.28%) attributed to a traumatic burst fracture. CONCLUSIONS: This study indicates that the use of a NG tube in primary anterior cervical spine surgery can be avoided. Comprehensive knowledge of anatomy and meticulous dissection may avoid the disastrous complication of esophageal rupture. This way the discomfort and complications associated with NG tube can be avoided.

Adjacent level discitis after anterior cervical discectomy and fusion (ACDF): a case report.

This report describes a case of spondylodiscitis occurring adjacent to levels at which anterior cervical discectomy and fusion was performed. The objective is to describe a rare cause of spondylodiscitis and discuss its successful management. Post-operative discitis involving the same level is a known occurrence. We report an interesting case of spondylodiscitis occurring at the adjacent level of fusion, and to our knowledge this is the first such case reported in literature. A two-level decompression and fusion was performed at C5-6 and C6-7 levels with PEEK cages and anterior cervical plating in a middle-aged gentleman for persistent axial neck pain and left-sided radiculopathy involving C6 and C7 distribution. After 6 weeks, the patient presented to us with complaints of mild paresthesia in the abdomen and extremities. Radiological investigations including plain radiographs and MRI revealed a surprising finding of discitis at C4-5 level with an associated epidural abscess. In view of the patient's myelopathic symptoms, surgical debridement and decompression of the spinal cord was performed. The plate and screws were removed, the cages were left intact, and the C4-5 disc level was reconstructed with tricortical iliac crest autograft. No further instrumentation was performed. The biopsy specimen from the disc at C4-5 level grew Serratia marcescens. It was contemplated that C4-5 discitis was initiated by inoculation of bacteria at the superior endplate of C5 by contaminated vertebral pins/drill-bit or screws. Adjacent level discitis is a rare but potentially serious complication of anterior cervical fusion. A high index of suspicion of infection is necessary if the patient complains of new symptoms after anterior cervical fusion. Thorough assessment and aggressive treatment is necessary for successful management.

Does Minimally Invasive Spine Surgery Minimize Surgical Site Infections?

STUDY DESIGN: Retrospective review of prospectively collected data. PURPOSE: To evaluate the incidence of surgical site infections (SSIs) in minimally invasive spine surgery (MISS) in a cohort of patients and compare with available historical data on SSI in open spinal surgery cohorts, and to evaluate additional direct costs incurred due to SSI. OVERVIEW OF LITERATURE: SSI can lead to prolonged antibiotic therapy, extended hospitalization, repeated operations, and implant removal. Small incisions and minimal dissection intrinsic to MISS may minimize the risk of postoperative infections. However, there is a dearth of literature on infections after MISS and their additional direct financial implications. METHODS: All patients from January 2007 to January 2015 undergoing posterior spinal surgery with tubular retractor system and microscope in our institution were included. The procedures performed included tubular discectomies, tubular decompressions for spinal stenosis and minimal invasive transforaminal lumbar interbody fusion (TLIF). The incidence of postoperative SSI was calculated and compared to the range of cited SSI rates from published studies. Direct costs were calculated from medical billing for index cases and for patients with SSI. RESULTS: A total of 1,043 patients underwent 763 noninstrumented surgeries (discectomies, decompressions) and 280 instrumented (TLIF) procedures. The mean age was 52.2 years with male:female ratio of 1.08:1. Three infections were encountered with fusion surgeries (mean detection time, 7 days). All three required wound wash and debridement with one patient requiring unilateral implant removal. Additional direct cost due to infection was $2,678 per 100 MISS-TLIF. SSI increased hospital expenditure per patient 1.5-fold after instrumented MISS. CONCLUSIONS: Overall infection rate after MISS was 0.29%, with SSI rate of 0% in non-instrumented MISS and 1.07% with instrumented MISS. MISS can markedly reduce the SSI rate and can be an effective tool to minimize hospital costs.

Cervical Footprint Anthropometry in Indian Population: Implications on Design of Artificial Disc Replacement Devices.

STUDY DESIGN: Cross-sectional study. PURPOSE: To accurately measure the dimensions of cervical endplates based on computed tomography (CT) scans in Indian population and assess accuracy of match with currently available cervical disc prostheses. OVERVIEW OF LITERATURE: The dimensions of currently available cervical disc replacement implants are based on early published geometrical measurements of vertebrae endplates for Caucasian population. To author's knowledge, similar study has not been published for patients from Indian subcontinent. METHODS: CT scans of cervical spine of patients from Indian subcontinent were collected and reviewed. Seventy patients (54 men and 16 women; aged 18-56 years with average of 37 years) who underwent CT scans of cervical spine were included in study. 3D CT scans of sub axial cervical spine (C3 to C7) were analyzed. The anterior-posterior (AP) and central mediolateral (CML) dimensions of superior and inferior endplates from C3 to C7 were measured using digital measuring system. RESULTS: A total of 560 endplates of 70 patients were included in the study. The AP diameter of cervical endplates ranged from 0.87 to 2.47 cm. The CML diameters ranged from 0.84 to 2.98 cm. For levels C3/C4 and C4/C5 for AP dimension Prestige-LP (90.5%) and Prodisc-C (89%) discs showed higher percentage of matching than Discover discs (58.5%). For CML diameter, Prestige-LP (69.5%), Prodisc-C (70%) and Discover (39.5%) discs showed almost similar matching with measured endplates. For levels C5/C6 and C6/C7 for AP dimension, Prestige-LP (67.25%), Prodisc-C (49.35%) and Discover (51.5%) discs showed similar matching. For CML diameter Prestige-LP (32%), Prodisc-C (27.5%) and Discover (42.2%) discs showed poor matching with measured endplates. CONCLUSIONS: This study indicates need for redesign of cervical disc prostheses to match Indian patients. The collected anthropometric dimensions from this study may be used to design and develop indigenous artificial total disc replacement prosthesis and even cervical cages in India. With the present study being a small pilot study, the authors recommend anthropometric CT measurements in larger number of Indian patients in order to validate footprint dimensions for designing better-matched prosthesis.

Technical note: the swimmer's view for cervical facet joint injections.

Image intensifier (C-arm) guided facet infiltration of a mixture of long acting local anaesthetic and corticosteroid is a safe and effective office procedure for cervical spondylosis. Visualisation of lower cervical anatomy using C-arm may not always be possible due to the shadow cast by the shoulders. We describe the successful adaptation of swimmer's view in such cases to carry out the injections.