Investigation into Cervical Spine Biomechanics Following Single, Multilevel and Hybrid Disc Replacement Surgery with Dynamic Cervical Implant and Fusion: A Finite Element Study

Cervical fusion has been a standard procedure for treating abnormalities associated with the cervical spine. However, the reliability of anterior cervical discectomy and fusion (ACDF) has become arguable due to its adverse effects on the biomechanics of adjacent segments. One of the drawbacks associated with ACDF is adjacent segment degeneration (ASD), which has served as the base for the development of dynamic stabilization systems (DSS) and total disc replacement (TDR) devices for cervical spine. However, the hybrid surgical technique has also gained popularity recently, but its effect on the biomechanics of cervical spine is not well researched. Thus, the objective of this FE study was to draw a comparison among single-level, bi-level, and hybrid surgery with dynamic cervical implants (DCIs) with traditional fusion. Reductions in the range of motion (ROM) for all the implanted models were observed for all the motions except extension, compared to for the intact model. The maximum increase in the ROM of 42% was observed at segments C5–C6 in the hybrid DCI model. The maximum increase in the adjacent segment’s ROM of 8.7% was observed in the multilevel fusion model. The maximum von Mises stress in the implant was highest for the multilevel DCI model. Our study also showed that the shape of the DCI permitted flexion/extension relatively more compared to lateral bending and axial rotation.

Hybrid surgery with PEEK rods for lumbar degenerative diseases: a 2-year follow-up study

Background Finite element analyses and biomechanical tests have shown that PEEK rods promote fusion and prevent adjacent segment degeneration. The purpose of this study was to evaluate the effects and complications of hybrid surgery with PEEK rods in lumbar degenerative diseases. Methods From January 2015-December 2017, 28 patients who underwent lumbar posterior hybrid surgery with PEEK rods were included in the study. The patients were diagnosed with lumbar disc herniation, lumbar spinal stenosis, or degenerative grade I spondylolisthesis. Before the operation and at the last follow-up, the patients completed lumbar anteroposterior and lateral X-ray, dynamic X-ray, MRI examinations. In addition, at the last follow-up the patients also completed lumbar CT examinations. The radiographic parameters, clinical visual analog scale (VAS) score and Oswestry disability index (ODI) score were compared. Results The average age of the patients was 44.8 ± 12.6 years, and the average follow-up duration was 26.4 ± 3.6 months. The VAS score improved from 6.3 ± 1.6 to 1.0 ± 0.9, and the ODI score decreased from 38.4 ± 10.8 to 6.8 ± 4.6. The fusion rate of the fused segment was 100%. There were no significant changes in the modified Pfirrmann classifications or disc height index for the nonfused segments and the upper adjacent segments from pre- to postoperatively. No cases of screw loosening, broken screws, broken rods or other mechanical complications were found. Conclusion Hybrid surgery with PEEK rods for lumbar degenerative diseases can yield good clinical results and effectively reduce the incidence of complications such as adjacent segment diseases.

Are Congenital Cervical Block Vertebrae a Risk Factor for Adjacent Segment Disease? A Retrospective Cross-Sectional CT and MR Imaging Study

Adjacent segment disease (ASDI) is a well-described complication of spinal fusion surgery that may ultimately lead to spinal stenosis and repeated surgical intervention. Although congenital block vertebrae also present with degenerative changes in the adjacent segments, this has not yet been systematically investigated. The aim of this study was to assess the presence and degree of ASDI in congenital cervical block vertebrae. Methods: A total of 51 patients with congenital vertebral fusion in one cervical segment were analysed in this IRB-approved retrospective cross-sectional study using available CT/MR imaging. Exclusion criteria were prior spinal surgery and the presence of additional hereditary abnormalities. We assessed the severity of degenerative changes using a sum score. The sum score for adjacent and non-adjacent segments was then divided by the highest possible degeneration score, which resulted in a ratio of severity for adjacent and remaining segments (ranging from 0 to 1). Results: Overall, 35 of 51 patients (68.6%) showed evidence of ASDI, and 34 of 51 patients (66.7%) also showed degenerative changes in the remaining segments. The severity score was significantly higher (p = 0.025) in the segments adjacent to the congenital block vertebrae (mean value 0.307) compared to the non-adjacent segments (mean value 0.188). Conclusions: Our results suggest that ASDI is also caused by congenital block vertebrae of the cervical spine.

Effect of Discectomy on Dynesys Dynamic Fixation in the Treatment of Lumbar Degenerative Diseases

Objective. To compare the effect of decompression of the spinal canal with or without discectomy on the clinical efficacy of Dynesys dynamic fixation treatment in lumbar degenerative diseases. Methods. A total of 62 patients treated for single-segment lumbar degenerative disease from October 2010 to November 2017 were retrospectively analyzed. All patients underwent decompression of the spinal canal with Dynesys dynamic fixation and were divided into two groups. Twenty-seven patients in group A did not undergo discectomy, and 35 patients in group B underwent discectomy. The intervertebral height, range of motion, Pfirrmann grade of the surgical segment and the upper adjacent segment, function scores, and operation information were compared. Results. All patients were followed up for an average of 30.7 ± 11.5 months. At the final follow-up, the intervertebral height and range of motion of the surgical segment decreased significantly in both group A and B ( p < 0.05 ), the range of motion of the upper adjacent segment increased significantly ( p < 0.05 ), and the intervertebral height did not change significantly ( p < 0.05 ). The retained percentages of surgical segment intervertebral height and ROM in group A were significantly better than those in group B ( p < 0.05 ). The intervertebral height ( p > 0.05 ) and range of motion ( p < 0.05 ) of the surgical segment in group A were higher than those in group B. The surgical segment Pfirrmann grading of group A was better than that of group B ( p < 0.05 ). Conclusion. Dynesys in the treatment of lumbar degenerative diseases may lead to a good clinical effect. In selected cases without discectomy, the range of motion and intervertebral height may be better preserved, and disc degeneration may be reduced.

Post-operative Intussusception, a rare case in pediatric, National Center for Paediatric Surgery, Gezira State, Sudan; 2021

Intussusception is defined by Treves in 1899 as invagination of segment of bowel into adjacent segment usually proximal into distal. It’s a common cause of abdominal emergencies especially in children two years of age and younger. It accounts for 1 in 2000 infants and children and results in intestinal obstruction. Post-operative intussusception is one of the rare etiologies of intestinal obstruction that represents 0.01 to 0.25% after laparotomies and 5 -10% of all early postoperative intestinal obstructions. Our case is a ten years old female presented to the National Center for Pediatric Surgery; Gezira state; Sudan; February 2021 complaining of abdominal distention and constipation for 6 days. She had past history of acute appendicitis due to which she underwent emergency opened appendectomy. Her condition started one day after appendectomy. O/E : patient looks ill, febrile, not pale or jaundice; PR:140b/m; RR:25c/m; abdominal examination show: distended abdomen with full flanks, unhealed lanz incision with small amount of pus discharge; no dilated veins or visible peristalsis; hernia orifice were intact; lower abdomen was tense & tender; no palpable mass; DRE: rectum contains impacted hard stool. Emergency explorative laparotomy was done. Findings: Ileocecal intussusception, bowel was healthy and viable. Simple reduction was done. Conclusion and Recommendations: Post-operative intussusception usually associated with bowel ischemia and necrosis which is not consistent with our case. We highly recommended abdominal ultrasonography, CT scan; when there is a high index of suspicion.

Revision Surgery for Symptomatic Adjacent Segment Disc Degeneration after Initial Anterior Cervical Fusion: Is ROI-C Better than Plate-Cage Construct?

The optimal revision surgical strategy for patients who develop symptomatic adjacent segment disc degeneration (ASD) is controversial. The risks of intraoperative complications, especially the incidence of dysphagia, were relatively high for revision surgeries. This study was aimed at comparing the efficacy of revision surgery using a traditional plate-cage construct and zero-profile anchored spacer (ROI-C) device in treating symptomatic ASD after initial anterior cervical discectomy and fusion (ACDF) surgery. Forty-two patients who developed symptomatic ASD were retrospectively analyzed and classified into two groups (plate-cage group and ROI-C group). The clinical and radiological results were compared. We further evaluated the complication of dysphagia and dysphagia-related risk factors in these patients. The JOA and NDI scores, C2-7 lordotic angle, and intervertebral space height were significantly improved after revision surgery in both groups. The operative time and intraoperative blood loss both significantly decreased in the ROI-C group. The incidence of postoperative dysphagia was much lower in the ROI-C group than in the plate-cage group (18.75% vs. 57.69%; P = 0.01 ). The presence of dysphagia after initial surgery ( P = 0.003 ) and revision surgery type ( P = 0.01 ) was significantly related to the presence of dysphagia after revision surgery. These results indicated that both the plate-cage construct and ROI-C are effective in treating symptomatic ASD. However, compared with the traditional plate-cage construct, ROI-C with less operative time, less blood loss, and lower incidence of dysphagia is more suitable. Furthermore, ROI-C should preferably be used for patients who present with dysphagia after initial cervical surgery. This study will provide clinical guidance for spinal surgeons to choose the zero-profile device in treating specific and complicated cases, which will significantly improve the therapeutic efficacy of symptomatic adjacent segment degeneration.