The aim of this study was to assess the result of Atlantal lateral mass and axis pedicle screw fixation for the treatment of unstable C2 odontoid fracture. We investigated the clinia records of 20 patients suffered from unstable C2 odontoid fracture whom received an Atlantal lateral mass and axis pedicle screw fixation at Phu Tho General hospital from 1/2012 to 12/2015.
JOURNAL OF MEDICAL RESEARCH SURGERY RESULT ASSESSMENT OF C1 LATERAL MASS AND C2 PEDICLE SCREW FIXATION IN TREATING UNSTABLE C2 ODONTOID/ DENS FRACTURE IN PHU THO GENERAL HOSPITAL Son Nguyen Van1, Toan Do Thi Thanh2, Ngoc Nguyen Huy1, Hoat Luu Ngoc2 Phu Tho General Hospital, Vietnam; 2Hanoi Medical University, Vietnam Superior cervical spinal lesions account for 25% of cervical spinal lesion Due to the special structure of superior cervical spine and the diversity of anatomical lesions, various non-surgical treatment methods such as Mini Verve powder, Halo frame, continuous traction, as well as surgical methods such as occipital splints, screwing through joints, C1 - C2 posterior arch binding, screwing through the odontoid process have been applied to treat these lesions.Comparing these techniques, the fixation of the C1 lateral mass and C2 pedicle with polyaxial screws has many advantages and has been widely applied in recent years The aim of this study was to assess the result of Atlantal lateral mass and axis pedicle screw fixation for the treatment of unstable C2 odontoid fracture We investigated the clinia records of 20 patients suffered from unstable C2 odontoid fracture whom received an Atlantal lateral mass and axis pedicle screw fixation at Phu Tho General hospital from 1/2012 to 12/2015 Of all the patients, no intraoperative complications were observed The average recovery time was 15 days, as being judged by clinical systems after surgery without major neurological complications and wound infection We concluded that the C1 lateral mass and C2 pedicle screw fixation for treatment of unstable odontoid fracture is a suitable option for these conditions with a high success rate and few complications Keywords: C1 lateral mass, C2 pedicle screw fixation, unstable C2 odontoid/dens fracture I INTRODUCTION line, solidifying the vertebrae and maintaining C2 Odontoid fractures account for 10 - C1 - C2 rotational movement The bone weld- 20% of cervical spine fractures However, only ing rate with this technique is approximately type II unstable odontoid fractures, or included 90% However, this technique is difficult to with C1 - C2 dislocation, are candidates for perform when the fractured odontoid is com- surgery [1 - 3] These surgeries would solidify bined with C1 - C2 dislocation [3] the vertebrae and decompress it if needed There are multiple treatment methods for C2 odontoid fracture and two main types of treatments are anterior fusion and posterior fusion: Posterior fusion to achieve stable fixation of C1 - C2 junction consists of multiple different methods such as Magerl’s screw interarticulation C1 - C2 surgery with a relatively Anterior fusion by screw inter-articulation high bone welding rate of 78 - 99% However, odontoid was first performed by Bohler This the risk of damage to the vertebral artery is technique involves directly fixing the fractured high and this method is difficult to perform to severe C1 - C2 dislocation in patients with a Corresponding author: Do Thi Thanh Toan, Ha Noi Medical University Email: dothithanhtoan@hmu.edu.vn Received: 15/7/2018 Accepted: 18/11/2018 JMR 116 E3 (7) - 2018 thoracic kyphosis (Hunchbacked) [4; 5] In 2001, Harms and Melcher disseminated the technique of C1 lateral mass and C2 pedicle screw fixation Harms’ C1 - C2 fixation method 53 JOURNAL OF MEDICAL RESEARCH is a suitable option with low risk, easily mend- vertebrae, classification of the spinal damage, able C1 - C2 and high bone welding rate [6] determination of the anatomical structure of We studied and applied the posterior C1 the vertebrae and C1 lateral mass and meas- lateral mass and C2 pedicle screw fixation for urement the size of C2 stem and to have a treating unstable C2 odontoid fracture and post-op precision of the position and location dislocated C1 - C2 in order to evaluate the of screw insertion by 64 rows of computed result as well as the advantages and disad- tomography with perioperative vertebral artery vantages of this method rendering II METHODS Subjects Patients who suffered from unstable C2 odontoid fracture and received a atlantal lateral mass and axis pedicle screw fixation at Phu Tho General Hospital in years, from 01/2012 to 12/2015 + Assessment of the spinal cord, soft tissue and to determine patient prognosis through MRI Operative technique The patients received tracheal intubation in the prone position and their heads were fixed on May-Few frame The incision was made along to the ligamentum flavum, in the bottom Inclusion criteria of the occipital C5, C6 The lower bone mem- + Suffered from unstable C2 odontoid frac- brane of muscle mass next to spondylosis was ture + Were operated in atlantal lateral mass and axis pedicle screw fixation then incised to the outer edge of C2 - C3 joint The lower bone membrane above the C1 posterior arch was then exposed to enable the visualization of the C1 lateral mass and to al- Methods low for the inner side of the C1 lateral mass - Study design: A case series study The vertebral artery runs along artery channel - Time: from 1/2012 to 12/2015 above C1 posterior arch, and the C2 nerve - Place: Phu Tho General hospital - Sample size and Sampling: Total sampling during the study period is 20 patients met criteria They were all included in the study root usually lies from lateral mass to the C1 posterior arch After protecting vertebral artery and C2 root by high-speed grinding with 3mm drill bit into the center of C1 lateral mass, aim the screw a 10 - 15 degrees to the center ac- - Variables cording to horizontal plane The screw fixa- + Perioperative clinical symptoms tions into the C1 lateral mass are 26 – 34 mm + Assessment of nerve damage according to ASIA scale long and 3.5 mm in diameter was then performed The guiding mark to place the screw on the C2 stem was one third the length in the + Assessment and classification of C1 - C2 center of C2 joint block The screw was then damage through conventional X-ray imaging directed to the inner, upper edge of C2 arch, (straight, lateral, open- mouth) and thereafter was aimed 15 -20 degrees to + Assessment of the condition of the 54 center and upwards 20 degrees The fixation JMR 116 E3 (7) - 2018 JOURNAL OF MEDICAL RESEARCH rod for the C1 - C2 was then placed The outer to refuse answering questions that they did not section of the C1 and C2 posterior arches want to answer and stop at anytime they were then grinded and grafted by part of the wanted C3 spondylosis Muscles are then grafted into III RESULTS the spondylosis behind the C2 Closure of the skin by sutures The average age of patients was 35.2 years old; the youngest patient was 15 years Research ethics old while the oldest was 75 years old There The research protocol was conformed to were 18 male and female patients who par- the Helsinki Declaration and all the interviews ticipated in the study have been conducted with the consent form The primary causes for fractured odontoid sent to the study subjects or to their parents if were traffic accidents and falls Among 20 they were under 17 years old at the point of study patients, traffic accidents accounted for being interviewed Respondents had the right and falls accounted for 12 Table Clinical signs Clinical signs Cases number Ratio % High neck pain 18 90% Sensory disorder 10 50% Circular muscle disorder 10% Quadriplegia 5% According to the Anderson and D’Alonzo classification, all 20 study participants had type odontoid fracture Result from Table shows that 18 patients (90%) had neck pain, 10 patients (50%) reported numbness on both hands and (10%) patients had post-traumatic circular muscle disorder There was only patient who has quadriplegia, MRI showed spinal stenosis corresponding to the injury but no obtrusion to the artery The C1 lateral mass and the C2 pedicle screw fixation had been, as indicated by comparing pre- and postoperative images, successfully performed in all patients There were no cases of vertebral artery injury or other complications during operation Mending was performed relatively easily Two patients with sensory disorder and circular muscle disorder were required to decompress C1 posterior arc, MRI revealed compressed muscles caused by dislocated C1 - C2 After the surgery, 18 patients had reported fewer bouts of neck pain as well as hand numbness Ninety percent of them report no circular muscle disorder post-operation One patient who had quadriplegia due to compressed C2 - C3 spinal cord are able to walk again after year undergoing surgery but have not completely recovered with numbness in both hands still occurred JMR 116 E3 (7) - 2018 55 JOURNAL OF MEDICAL RESEARCH Pre-surgery images a Odotoid/ dens Post surgery images fracture pre-surgery images b Post surgery images of C1 lateral mass screw fixation c Images of vertebral arteries e Images of posterior C2 spinous process d Image of post C1 and C2 screw fixation f Post screw fixation image of C1 and C2 fracture Figure Pre and post surgery images 56 JMR 116 E3 (7) - 2018 JOURNAL OF MEDICAL RESEARCH Case illustration Placing the screw on the inner upper edge A 33-year-old male patient was the victim of the C2 pedicle, direct toward the center at of a road accident with his head and neck an angle of 20 degrees and upward of 20 de- bump against the road After falling, he grees Set fixed rod to join C1 - C2 The corti- remained conscious but with severe neck cal bone in the outermost of arcs C1 and C2 pain, exacerbated by movement With neck was crusted and transplanted by bone of C3 movement restrained, CT scan of the neck posterior spinosity The tendon was stitched spine showed C2 odontoid process fracture into C2 posterior spinosity Close the skin ac- type II cording to the anatomical layers The patient was scanned by 64-slide CT Postoperative patient was given antibiotics, scanner to determine the anatomical structure , then could sit up and exercise early, thread of the C1 - C2 vertebral body, the C1 lateral cut and discharged from the hospital 15 days mass, examine the size of the pedicle of C2, after the surgery and the vertebral artery location when passing C2 and C1 IV DISCUSSION Surgerical Technique: Endotracheal anes- Surgical treatment for C2 odontoid process thesia with the posture of lying in the prone fracture has many different methods In gen- position The head was fixed on May-Few eral, there are two main types of surgery: fron- frame Incision of skin was along the posterior tal way surgery and posterior way surgery interspinous line from the point under the outer Frontal way surgery by screwing through the occiput to the C5, C6 spinous process Dis- odontoid apophysis was first performed by section of the muscle mass beside the bilat- Bohler [7; 8] This technique directly fixes the eral spinal spinosity under the periosteum to fracture, strengthens the spine of the neck, the outer edge of joint C2 - C3 Dissection be- preserves the rotation of C1C2 Bone weld neath the periosteum, above C1 posterior arch rate is about 90% But this technique is difficult to both sides to see the C1 lateral mass The to perform when odontoid process fractures inner edge of C1 lateral mass was palpable involve severe C1C2 dislocations The vertebral artery was in the artery groove Posterior way surgery to harden C1C2 also above the C1 posterior arch Normally, C2 has many different methods such as lateral radicle is located from lateral mass to the C1 mass screwing surgery C1 and the C2 pedicle posterior arch After protecting the vertebral that has many advantages In 2002, Author artery and C2 radicle, high-speed grinding Goel reported 160 cases that were operated drills with a 3-mm bit were used in the middle with splint screw at C1 lateral mass and C2 of C1 lateral mass to screw toward the center pedicle; no patient then had neurological and crossing horizontal plane made the angle of vascular complications [9] In 2001, Harms 10 degrees After Taro set screw 34mm long, and Melcher reported 37 cases of screwing C1 diameter 3.5 mm into the C1 lateral mass The lateral mass and C2 pedicle that also resulted point to place the screw through the C2 pedi- in 100% bone and no vascular and neurologic cle was in the middle of the upper one third of complication [6] In 2010, Mummaneni studied the C2 pedicle 42 cases of C1 lateral mass screwing showing JMR 116 E3 (7) - 2018 57 JOURNAL OF MEDICAL RESEARCH high bone weld rate, reduced neck pain and pedicle, because if the C2 pedicle were too improved neurological function [4] small, this technique could not be applied Regarding to determining the bolt point on During surgery, continuously use C-Arm 3D to C1 lateral mass, there are many different well control the path of the screw to reduce the views: The authors Harms and Goel screwed risk of injury to vertebral artery and spinal directly to the mass under posterior arch C1 cord after rolling up the C2 radicle downward [1] Tan, Wang and associates screwed on C1 to the lateral mass for good results In this case, we screwed directly on C1 posterior arch and found many advantages: there is no need to roll up C2 radicle, the screw was quite firm because the part of screw in the bone was long, which was favorable for C1C2 dislocation treatment However, the bolt point was just on the posterior arch, near the vertebral artery groove, thus, vertebral artery is vulnerable [10] Therefore, according to us, Figure Vertebral arterial abnormality understanding of the path of the vertebral image artery before the surgery by using 64-slide construction scan would help to avoid this complication Through V CONLUSION Screwing surgery through C1 lateral mass the study, we found that and C2 pedicle should be applied to patient preoperative screening was of paramount with sprained C1C2, odontoid process fracture importance Patients are required to have a 64 -slide construction scan to determine the anatomy of the path of lateral vertebral artery because, according to the literature, 15 to 20% of patients have abnormalities of anatomical vertebral artery We met a case of odontoid process fracture type II, 64-slide construction scan showed abnormality of the path of left vertebral artery that went over the posterior anterior facet of C1 lateral mass In that case, we had to use the surgical method of screwing through the C1C2 joint and the patient also had surgery successfully fix but keeping ability to exercise cervical spine after surgery and it’s safe However, it is needed to carry out preoperative examination thoroughly together with modern medical equipment, and it needs high accuracy and surgeon’s experiences ACKNOWLEDGEMENTS We highly appreciate the Phu Tho provincial general hospital for providing the data, allowing and supporting us to perform our research We would like to thank Department of Vertebral arterial abnormality image Biostatistic and Health Informatic, Hanoi Medi- It is important to take 64-slide scan to have cal University for technical assistance and ed- anatomical determination of the size of the C2 58 type II as it results in high bone weld rate, firm iting the manuscript JMR 116 E3 (7) - 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2018 JOURNAL OF MEDICAL