Machine learning application for prediction of surgical site infection after posterior cervical surgery.

Surgical site infection (SSI) is one of the most common complications of posterior cervical surgery. It is difficult to diagnose in the early stage and may lead to severe consequences such as wound dehiscence and central nervous system infection. This retrospective study included patients who underwent posterior cervical surgery at The Second Affiliated Hospital and Yuying Childrens Hospital of Wenzhou Medical University from September 2018 to June 2022. We employed several machine learning methods, such as the gradient boosting (GB), random forests (RF), artificial neural network (ANN) and other popular machine learning models. To minimize the variability introduced by random splitting, the results underwent 10-fold cross-validation repeated 10 times. Five measurements were averaged across 10 repetitions with 10-fold cross-validation, the RF model achieved the highest AUROC (0.9916), specificity (0.9890) and precision (0.9759). The GB model achieved the highest sensitivity (0.9535) and the KNN achieved the highest sensitivity (0.9958). The application of machine learning techniques facilitated the development of a precise model for predicting SSI after posterior cervical surgery. This dynamic model can be served as a valuable tool for clinicians and patients to assess SSI risk and prevent it in clinical practice.

Effect of a bilateral inter-semipinal plane block on quality of recovery in patients undergoing posterior cervical surgery / 临床麻醉学杂志

Objective To determine how inter-semispinal plane block(ISPB)affects how well in-dividuals recover after having posterior cervical surgery.Methods Seventy-two patients chosen for elective posterior cervical surgery from January to April 2023,41 males and 31 females,aged 18-64,BMI 18-28 kg/m2,ASA physical status Ⅱ or Ⅲ,were divided into two groups using randomized block design:the ISPB group(group I)and the control group(group C),36 patients in each group.Before anesthesia induc-tion,all patients were positioned at the 5th cervical vertebra plane using ultrasound,and 0.25％ropivacaine 20 ml or the same volume of physiological saline were injected into the fascia plane between the bilateral semispinalis cervicis and semispinalis capitis muscles.Anesthetic induction began 15 minutes after injection.QoR-40 and Pittsburgh sleep quality index(PSQI)were recorded 1 day before surgery,1 day and 2 days after surgery,and pain numerical scores(NRS)were recorded 1,6,12,24,and 48 hours after surgery.The number of effective PCIA compressions,the total number of PCIA compressions,the number of relief analgesia,the dosage of sufentanil,remifentanil intraoperatively and postoperatively,and dosage of pentazo-cine postoperatively were recorded.The occurrence of postoperative nausea and vomiting(PONV),the time of first independent walking and oral feeding after surgery,and puncture related complications,such as he-matoma,infection,and local anesthetic poisoning were recorded.Results Compared with 1 day before sur-gery,the total QoR-40 scores and various dimensional scores in the two groups were significantly decreased,while PSQI were significantly increased 1 day and 2 days after surgery(P＜0.05).Compared with group C,the total QoR-40 scores and various dimensional scores except self-care capacity were significantly in-creased,while PSQI were significantly decreased 1 day and 2 days after surgery(P＜0.05),NRS were significantly decreased 1,6,12,and 24 hours after surgery(P＜0.05),the number of effective PCIA compressions,the total number of PCIA compressions,the number of relief analgesia,the dosage of remifentanil intraoperatively,the dosage of pentazocine postoperatively and the occurrence of PONV were significantly decreased(P＜0.05),the time of first independent walking and oral feeding after surgery were significantly shortened in group Ⅰ(P＜0.05).There were no puncture related complications occurred in the two groups.Conclusion Bilateral ISPB can effectively improve the postoperative sleep of patients undergoing posterior cervical surgery,reduce postoperative pain and the incidence of PONV,and improve the postoperative recovery quality.

Do patients with Hirayama disease require surgical treatment? A review of the literature.

The main clinic characteristic of Hirayama disease (HD) is atrophy of the distal muscles in the upper limbs. Recently, an increasing number of HD cases have been reported. Many HD patients have persistently progressive symptoms and conservative treatments failed. This article aims to review the current status of the field and summarizes the main surgical treatment options for patients with HD. A comprehensive search of the PubMed and the Web of Science databases was conducted from their inception to September 15th, 2022. Search terms included "juvenile muscular atrophy of upper extremity", "Hirayama disease" and "surgery". A total of 169 relevant publications were identified and 29 articles were finally reviewed. Current surgical treatments for HD are either anterior cervical surgery or posterior cervical surgery. The two approaches can effectively stop the disease. However, no studies have compared the advantages and limitations of the two surgical methods. The previous view that HD can be improved with conservative treatment has been challenged. In many studies, surgical treatment has been shown to improve the hand function in patients with HD. However, there is still controversy about the methods of anterior and posterior cervical surgery. Future research could focus on exploring the advantages and limitations of different surgeries.

[Safety and efficacy of different doses of tranexamic acid in posterior cervical laminectomy with lateral mass screw fixation and bone graft fusion].

Objective: To investigate the safety and efficacy of different doses of tranexamic acid (TXA) in posterior cervical laminectomy with lateral mass screw fixation and bone graft fusion by a prospective clinical study. Methods: The middle-aged and elderly patients with cervical spondylotic myelopathy, who were admitted between January 2020 and January 2022 and scheduled to undergo posterior cervical laminectomy with lateral mass screw fixation and bone graft fusion, were studied as the research subjects. Among them, 165 patients met the selection criteria and were included in the study. The patients were allocated into 3 groups ( n=55) by random double-blind lottery. Groups A and B were given intravenous infusion of TXA at 30 minutes before operation according to the standards of 15 and 30 mg/kg, respectively; and group C was given normal saline in the same way. There was no significant difference in gender, age, body mass index, and preoperative D-dimer, hemoglobin (Hb), and hematocrit (HCT) between groups ( P>0.05). The intraoperative bleeding, intraoperative blood transfusion, postoperative drainage volume, drainage days, and postoperative hospital stay were recorded. The Hb, HCT, and D-dimer were compared before operation and at 3 days after operation. Venous ultrasonography of the lower extremities was taken after operation to assess thrombosis; and the postoperative hematoma and epilepsy were also observed. Results: All operations were successfully completed, and the incisions healed by first intention. The differences in intraoperative bleeding volume, postoperative drainage volume, drainage days, and postoperative hospital stay between groups were significant ( P<0.05). The above indexes were significantly less in group B than in groups A and C. During operation, 14 patients in group A and 23 patients in group C were transfused, and no patient in group B had blood transfusions. Compared with groups A and C, the blood transfusion volume in group B significantly decreased ( P<0.05), and the difference between groups A and C was not significant ( P>0.05). There was no significant difference in the differences of D-dimer, Hb, and HCT before and after operation between groups ( P>0.05). At 5 days after operation, the venous ultrasonography of the lower extremities showed that the 2 cases of intermuscular venous thrombosis occurred in groups A, B, and C, respectively. No hematoma or epilepsy occurred after operation. Conclusion: The application of 15 and 30 mg/kg TXA in posterior cervical laminectomy with lateral mass screw fixation and bone graft fusion can reduce intraoperative bleeding and postoperative drainage volume, postoperative drainage days, and postoperative hospital stay. And application of 30 mg/kg TXA can reduce intraoperative blood transfusion, without increasing the risk of lower extremity venous thrombosis, hematoma, and epilepsy.

Potential Surgical Implications of Internal Jugular Stenosis in a Craniocervical Junction Meningioma.

We report a case of a 61-year-old lady presenting with several weeks of progressive left-sided weakness, and found to have a foramen magnum meningioma. She was counselled on surgical resection of the tumour, and a preoperative computed tomography angiogram (CTA) was obtained for operative planning purposes. CTA demonstrated incidental bilateral internal jugular vein (IJV) stenosis, with enlarged extracranial collateral vessels and elongated styloid processes. The main surgical concern was potential injury of the extracranial collateral vessels during operative exposure, which may compromise her intracranial venous outflow in light of the IJV stenosis. A doppler ultrasound scan of the IJVs was performed, which demonstrated that blood flow was still present through both vessels. Through careful soft tissue dissection during surgery, potential complications and injury to the extracranial collaterals were avoided. We performed a literature review of the incidence of IJV stenosis, its associated conditions, and potential surgical implications. Complications from injury to vital collateral extracranial vessels should be considered during preoperative planning in patients with anatomical variants or risk factors for IJV stenosis, as seen in this case.

Three Column Cervical Fracture-Dislocation in a 3-Year-Old Boy.

Complete traumatic cervical fracture-dislocation with spinal cord transection in children is a rare entity with no evidence-based guidelines on management. The authors reviewed the literature for pediatric spinal cord injury and present the case of a 3-year-old with traumatic cervical fracture-dislocation and spinal cord transection who presented as a cervical-6 complete spinal cord injury (ASIA A). His other organ systems injured included liver, spleen, bowel, and abdominal aortic injury. The patient underwent halo placement for preoperative reduction followed by open reduction and internal fixation with posterior segmental instrumented fusion. Intraoperatively, the patient had motor evoked potential signals present below the level of his injury. Early postoperative follow-up demonstrated that, although his leg function did not improve, he did demonstrate improvement in upper extremities. This is a rare case of complete cervical spinal cord transection in a pediatric patient. We elected to manage this challenging case with initial external reduction and orthosis with a halo vest followed by acute posterior cervical fusion. Despite a cervical-6 injury level on clinical exam, there was electrographic evidence of function below that level on intraoperative neuromonitoring. Postoperatively the patient has recovered some lost function.

Off-label usage of RhBMP-2 in posterior cervical fusion is not associated with early increased complication rate and has similar clinical outcomes.

BACKGROUND CONTEXT: Arthrodesis is important for the success of posterior cervical fusion (PCF), however, there exists limited data regarding the safety and efficacy of bone morphogenic protein (BMP) in PCF. PURPOSE: The primary objective was to evaluate early postoperative complications associated with BMP in PCF and determine whether BMP leads to adverse early clinical outcomes. A secondary objective was to determine the optimal location for BMP sponge placement, within the facet joint (IF) or elsewhere, and the optimal dosage/level. DESIGN: Retrospective, consecutive case-control study. PATIENT SAMPLE: Seven hundred sixty-five patients who underwent PCF OUTCOME MEASURES: Patient-reported outcomes (PROs), complications, arthrodesis, optimum dose/level of BMP METHODS: Surgical data, including preoperative diagnosis, levels fused, type of bone graft, BMP dose (when used), and fusion technique were recorded. Complications were assessed by reviewing the medical record encompassing the first 6-weeks postoperative. These included medical, neurological, and wound-related complications and reoperation. Neurological complications were defined as any new weakness, radicular pain, or numbness. PROs were collected, including SF36, VAS, EQ-5D, and NDI scores. To determine the optimal dosage and location for BMP placement, a sub-analysis was performed. RESULTS: There were no significant differences between the BMP and no BMP group with regards to wound complications, neurological complications, or reoperation. There were no differences in PROs between BMP and no BMP. Placement of BMP for IF and at a dose of 0.87 mg/level minimized wound-related complications. The BMP group had a higher fusion rate compared to the no BMP group (96% vs. 91%, p=.02) when assessed 1 year post-operatively. CONCLUSION: BMP was not associated with a higher rate of early complications after PCF when the dose was minimized. Complications thought to be associated with BMP, such as compressive seroma, radiculitis, and wound-related complications were not seen at a higher rate. PROs at early follow-up were similar. Placement of BMP for IF and at lower doses than previously reported may minimize complications.

Comparison of Accuracy and Clinical Outcomes of Robot-Assisted Versus Fluoroscopy-Guided Pedicle Screw Placement in Posterior Cervical Surgery.

STUDY DESIGN: This was a prospective controlled study. OBJECTIVE: To compare the accuracy and clinical outcomes of robot-assisted (RA) and fluoroscopy-guided (FG) pedicle screw placement in posterior cervical surgery. METHODS: This study included 58 patients. The primary outcome measures were the 1-time success rate and the accuracy of pedicle screw placement according to the Gertzbein-Robbins scales. The secondary outcome measures, including the operative time, intraoperative blood loss, hospital stay, cumulative radiation time, radiation dose, intraoperative advent events, and postoperative complications, were recorded and analyzed. The Japanese Orthopedics Association (JOA) scores and Neck Disability Index (NDI) were used to assess the neurological function of patients before and at 3 and 6 months after surgery. RESULTS: The rate of grade A was significantly higher in the RA group than in the FG group (90.6% and 71.1%; P < .001). The clinically acceptable accuracy was 97.2% in the RA group and 90.7% in the FG group (P = .009). Moreover, the 1-time success rate was significantly higher in the RA group than in the FG group. The RA group had less radiation time (P < .001) and less radiation dose (P = .002) but longer operative time (P = .001). There were no significant differences in terms of intraoperative blood loss, hospital stay, intraoperative adverse events, postoperative complications, JOA scores, and NDI scores at each follow-up time point between the 2 groups. CONCLUSIONS: The RA technique achieved higher accuracy and 1-time success rate of pedicle screw placement in posterior cervical surgery while achieving comparable clinical outcomes.

Cervical Deformity Patients Have Baseline Swallowing Dysfunction but Surgery Does Not Increase Dysphagia at 3 Months: Results From a Prospective Cohort Study.

STUDY DESIGN: Prospective cohort study. OBJECTIVES: Most studies of dysphagia in the cervical spine have focused on a degenerative patient population; the rate of dysphagia following surgery for cervical deformity (CD) is unknown. This study aims to investigate if surgery for cervical deformity results in postoperative dysphagia. METHODS: Patients with CD undergoing surgery from 2013 to 2015 were prospectively enrolled to evaluate dysphagia. Demographic, operative, and radiographic variables were analyzed. The Quality of Life in Swallowing Disorders (SWAL-QoL) was used to measure dysphagia. Paired t test, independent t tests, and bivariate Pearson correlations were performed. RESULTS: A total of 88 CD patients, aged 61.52 ± 10.52 years, were enrolled. All patients (100%) had 3-month SWAL-QoL for analysis. The baseline preoperative SWAL-QoL was 78.35. This is roughly the same level of dysphagia as an anterior cervical discectomy patient that is 3 weeks removed from surgery. Increasing body mass index (BMI) was correlated with decreased SWAL-QoL score (r = -0.30, P = .001). Age, gender, smoking, and Charlson Comorbidity Index (CCI) showed no significant correlations with preoperative SWAL-QoL. Patients with prior cervical surgery had a lower preoperative SWAL-QoL (P = .04). While 11 patients had acute postoperative dysphagia, CD surgery did not result in lower SWAL-QoL at 3 months (77.26 vs 78.35, P = .53). Surgical variables, including estimated blood loss (EBL), anterior or posterior fusion levels, steroid use, preoperative traction, staged surgery, surgical approach, anterior corpectomy, posterior osteotomy, and UIV (upper instrumented vertebrae) location, showed no impact on postoperative SWAL-QoL. Correction of cervical kyphosis was not correlated to 3-month SWAL-QoL scores or the change in SWAL-QoL scores. CONCLUSIONS: While patients undergoing surgery for cervical deformity had swallowing dysfunction at baseline, we did not observe a significant decline in SWAL-QoL scores at 3 months. Patients with prior cervical surgery and higher BMI had a lower baseline SWAL-QoL. There were no surgical or radiographic variables correlated to a change in SWAL-QOL score.

Pre-operative planning and rod customization may optimize post-operative alignment and mitigate development of malalignment in multi-segment posterior cervical decompression and fusion patients.

Patient-specific rods designed based on a particular pre-operative plan are a recent advancement to help achieve desired operative alignment goals. This study investigated the role of pre-operative planning and patient-specific rods on post-operative alignment and outcomes. Patients were grouped according to use of pre-operative planning and patient-specific, pre-contoured rods (PLAN) or absence of planning/rods (NON). Pre-operative and post-operative alignment were measured: cervical sagittal vertical axis (cSVA), cervical lordosis (CL), T1 Slope minus CL (TS-CL). Alignment differences between the groups were assessed using independent and paired samples t-tests. 34 patients were identified (15 PLAN, 19 NON). Pre- and post-operative CL, cSVA and TS were similar between the two groups (p > 0.05), though pre-operative TS-CL was slightly higher in PLAN patients (28.13° versus 18.42°, p = 0.049). There were no improvement differences pre- to post-operative for CL, cSVA and TS between the groups (p > 0.05). However, PLAN patients exhibited a greater correction of TS-CL, with an average of 5.8° decrease versus a 3.5° increase in TS-CL for NON patients (p = 0.015). PLAN patients did not demonstrate a significant change from pre- to post-operative alignment for cSVA or TS-CL (cSVA: 27.5 mm to 31.1 mm, p = 0.255; TS-CL: 28.1° to 22.3°, p = 0.13), though their TS-CL did trend towards significant post-operative improvement. In contrast, NON patients worsened in cSVA and TS-CL post-operatively (cSVA: 21.8 mm to 30.3 mm, p < 0.001; TS-CL: 18.4° to 22.0°, p = 0.035). Multi-segment posterior decompression and fusion patients have the potential to worsen with regards to post-operative alignment without pre-operative planning. Patients with pre-contoured rods and pre-operative planning exhibited a greater correction of TS-CL after surgery than un-planned cases, though limited by the pre-operative difference in cervical-thoracic mismatch between planned and unplanned cases. LEVELS OF EVIDENCE: III.

Incidence of C5 Palsy: Meta-Analysis and Potential Etiology.

BACKGROUND: Among the proposed hypotheses for C5 palsy, the most acceptable etiologies have been the tethering effect of the spinal nerve or reperfusion injury of the spinal cord. We performed a meta-analysis to determine a potential etiology of C5 palsy. METHODS: The PubMed, Embase, Web of Science, and Cochrane Library databases were searched up to 2017 for relevant studies of the incidence of C5 palsy after cervical decompression surgery. Relevant incident estimates of C5 palsy stratified by the surgical approach and underlying diagnosis were calculated using an appropriate meta-analysis. RESULTS: A total of 107 studies were included for our meta-analysis. The pooled incidence of C5 palsy was 0.00 (95% confidence interval [CI], 0.00-0.01) for anterior decompression in patients with radiculopathy, 0.04 (95% CI, 0.03-0.05) for anterior decompression and 0.07 (95% CI, 0.06-0.08) for posterior decompression in patients with myelopathy. A two-tailed t test with unequal variance accepted the null hypothesis of no differences in the incidence between anterior and posterior decompression in patients with myelopathy (P = 0.999) and rejected the hypothesis of no differences in the incidence between the patients with radiculopathy and myelopathy in anterior decompression (P < 0.001). CONCLUSIONS: With no significant difference found in the incidence of C5 palsy between anterior and posterior cervical decompression in patients with myelopathy, the tethering effect of the spinal nerve might not be a plausible etiology for C5 palsy. In contrast, we found a significantly greater incidence of C5 palsy in patients with myelopathy compared with those with radiculopathy undergoing anterior decompression, which might support the reperfusion injury of the spinal cord as the etiology of C5 palsy.

Use of intraoperative X-ray to differentiate between reducible versus irreducible atlantoaxial dislocation.

BACKGROUND: The treatment and classification of atlantoaxial dislocations (AADs) remain controversial. Here, we utilized intraoperative X-ray to differentiate between reducible and irreducible AADs. METHODS: Five patients were diagnosed as having irreducible AAD on dynamic and post-traction X-rays. Under general anesthesia, they were placed prone in a neutral position utilizing skeletal traction. The X-rays and motor evoked potential (MEP), were then monitored before, during, and after placing a thumb on the C2 spinous process and pushing it anteriorly to attain reduction. RESULTS: The intraoperative X-ray confirmed reducibility of AAD in four patients; they subsequently underwent a C1-C2 posterior fusion, which maintained that reduction. For the one patient with an irreducible AAD (despite thumb maneuver), an anterior release was required first to attain reduction, followed by posterior C1-C2 fusion. CONCLUSION: Here, we divided irreducible AAD into two categories: a) reducible-utilizing a thumb maneuver to compress/push the C2 spinous process forward with the patient positioned prone and b) irreducible-those who cannot be reduced with this technique. A posterior only approach was sufficient for those with "reducible" AAD, whereas those who could not be reduced required an anterior release followed by posterior fusion.

Risk factors for implant removal after spinal surgical site infection.

PURPOSE: Few studies have investigated the risk factors for implant removal after treatment for spinal surgical site infection (SSI). Therefore, there is no firmly established consensus for the management of implants. We aimed to investigate the incidence and risk factors for implant removal after SSI managed with instrumentation, and to examine potential strategies for avoiding implant removal. METHODS: Following a survey of seven spine centers, we retrospectively reviewed the records of 55 patients who developed SSI and were treated with reoperation, out of 3967 patients who had spinal instrumentation between 2003 and 2012. We examined implant survival rate and applied logistic regression analysis to assess the potential risk factors for implant removal. RESULTS: The overall rate of implant retention was 60% (33/55). A higher implant retention rate was observed for posterior cervical surgery than for posterior-thoracic/lumbar surgery (100 vs. 49%, P < 0.001). On univariate analysis, significant risk factors for implant removal included greater blood loss, delay of reoperation, and delay of intervention with effective antibiotics. Multivariate analysis revealed that a delay in administering effective antibiotics was an independent and significant risk factor for implant removal in posterior-thoracic/lumbar surgery (odds ratio 1.17; 95% confidence interval 1.02-1.35, P = 0.028). CONCLUSIONS: Patients with SSI who underwent posterior cervical surgery are likely to retain the implants. Immediate administration of effective antibiotics improves implant survival in SSI treatment. Our findings can be applied to identify SSI patients at higher risk for implant removal.

Anatomical anomalies of the V3 segment of the vertebral artery in the Polish population.

PURPOSE: The aim of this study is to evaluate the incidence of the anatomical anomalies of the V3 segment of the vertebral artery in the Polish population. There is conflicting evidence on the incidence of these anomalies: Asian-based studies show high incidence of 10 %, whereas the North American study identifies these anomalies in less than 1 % of patients. METHODS: 1800 computed tomography angiographies (CTA) obtained at the Barlicki University Hospital in Lodz, Poland, were reviewed retrospectively. RESULTS: All the patients were Caucasians. There were 968 males and 832 females. The mean age of the patients was 58. CTAs were obtained for the following reasons: stroke 1312, trauma 25, vascular/aneurysm 216, and intracranial haemorrhage 247. Vertebral artery hypoplasia was present in 360 cases (20 %). Persistent intersegmental artery (type I anomaly) was not found in any study. Fenestration of the V3 vertebral artery (type II) was recognized in three angiograms (0.16 %). Vertebral artery ending up as posterior inferior cerebellar artery (type III anomaly) was seen in 11 patients (0.61 %). CONCLUSIONS: Very low incidence of V3 segment anomalies does not justify in our opinion routine vascular imaging in patients undergoing posterior cervical instrumented procedures.

Preliminary documentation of the comparable efficacy of vitoss versus NanOss bioactive as bone graft expanders for posterior cervical fusion.

BACKGROUND: Laminectomies with posterior cervical instrumented fusions often utilize bone graft expanders to supplement cervical lamina/iliac crest autograft/bone marrow aspirate (BMA). Here we compared posterior fusion rates utilizing two graft expanders; Vitoss (Orthovita, Malvern, PA, USA) vs. NanOss Bioactive (Regeneration Technologies Corporation [RTI: Alachua, FL, USA]). METHODS: Two successive prospective cohorts of patients underwent 1-3 level laminectomies with 5-9 level posterior cervical fusions to address cervical spondylotic myelopathy (CSM) and/or ossification of the posterior longitudinal ligament (OPLL). The first cohort of 72 patients received Vitoss, while the second cohort or 20 patients received NanOss. Fusions were performed utilizing the Vertex/Rod/Eyelet System (Medtronic, Memphis, TN, USA) with braided titanium cables through the base of intact spinous processes (not lateral mass screws) cephalad and caudad to laminectomy defects. Fusion was documented by an independent neuroradiologist blinded to the study design, utilizing dynamic X-rays and two dimensional computed tomography (2D-CT) studies up to 6 months postoperatively, or until fusion or pseudarthrosis was confirmed at 1 year. RESULTS: Vitoss and NanOss resulted in comparable times to fusion: 5.65 vs. 5.35 months. Dynamic X-ray and CT-documented pseudarthrosis developed in 2 of 72 Vitoss patients at one postoperative year (e.g. bone graft resorbed secondary to early deep wound infections), while none occurred in the 20 patients receiving NanOss. CONCLUSION: In this preliminary study combining cervical laminectomy/fusions, the time to fusion (5.65 vs. 5.35 months), pseudarthrosis (2.7% vs. 0%), and infection rates (2.7% vs. 0%) were nearly comparable sequentially utilizing Vitoss (72 patients) vs. NanOss (20 patients) as bone graft expanders.

Posterior cervical fixation with a nitinol shape memory loop for primary surgical stabilization of atlantoaxial instability: a preliminary report.

OBJECTIVE: To evaluate a new posterior atlantoaxial fixation technique using a nitinol shape memory loop as a simple method that avoids the risk of vertebral artery or nerve injury. METHODS: We retrospectively evaluated 14 patients with atlantoaxial instability who had undergone posterior C1-2 fusion using a nitinol shape memory loop. The success of fusion was determined clinically and radiologically. We reviewed patients' neurologic outcomes, neck disability index (NDI), solid bone fusion on cervical spine films, changes in posterior atlantodental interval (PADI), and surgical complications. RESULTS: Solid bone fusion was documented radiologically in all cases, and PADI increased after surgery (p<0.05). All patients remained neurologically intact and showed improvement in NDI score (p<0.05). There were no surgical complications such as neural tissue or vertebral artery injury or instrument failure in the follow-up period. CONCLUSION: Posterior C1-2 fixation with a nitinol shape memory loop is a simple, less technically demanding method compared to the conventional technique and may avoid the instrument-related complications of posterior C1-2 screw and rod fixation. We introduce this technique as one of the treatment options for atlantoaxial instability.

The incidence of bifid c7 spinous processes.

For posterior cervical surgery, if the operation only involves the lower cervical area, counting from C2 is impractical and the level may not be visible on X-rays. In such cases, we usually place a marker at the top of the incision and also rely on the size and monofid shape of the C7 spinous process. Relying on the C7 morphology, however, we initially instrumented the wrong levels in a case where the patient had a bifid C7 spinous process. We therefore sought to determine the frequency of bifid cervicothoracic spinous processes. Computed tomography axial images of C6, C7, and T1 from 516 patients were evaluated. The spinous processes were classified into three categories: "bifid," "partially bifid," and "monofid." C6 spinous process was monofid in 47.9% of cases, partially bifid in 4.2% of cases, and bifid in 47.9% of cases. C7 spinous process was monofid in 99.2% of cases, partially bifid in 0.5% of cases, and bifid in 0.3% of cases. T1 was monofid in all cases. A truly bifid C7 spinous process occurs 0.3% of the time and therefore is not a reliable landmark for choosing fusion levels. This knowledge hopefully helps prevent the type of wrong-level instrumentation that we performed.

Posterior Cervical Fixation with a Nitinol Shape Memory Loop for Primary Surgical Stabilization of Atlantoaxial Instability: A Preliminary Report

OBJECTIVE: To evaluate a new posterior atlantoaxial fixation technique using a nitinol shape memory loop as a simple method that avoids the risk of vertebral artery or nerve injury. METHODS: We retrospectively evaluated 14 patients with atlantoaxial instability who had undergone posterior C1-2 fusion using a nitinol shape memory loop. The success of fusion was determined clinically and radiologically. We reviewed patients' neurologic outcomes, neck disability index (NDI), solid bone fusion on cervical spine films, changes in posterior atlantodental interval (PADI), and surgical complications. RESULTS: Solid bone fusion was documented radiologically in all cases, and PADI increased after surgery (p<0.05). All patients remained neurologically intact and showed improvement in NDI score (p<0.05). There were no surgical complications such as neural tissue or vertebral artery injury or instrument failure in the follow-up period. CONCLUSION: Posterior C1-2 fixation with a nitinol shape memory loop is a simple, less technically demanding method compared to the conventional technique and may avoid the instrument-related complications of posterior C1-2 screw and rod fixation. We introduce this technique as one of the treatment options for atlantoaxial instability.

Posterior cervical fixation with nitinol shape memory loop in the anterior-posterior combined approach for the patients with three column injury of the cervical spine : preliminary report.

OBJECTIVE: The authors reviewed clinical and radiological outcomes in patients with three column injury of the cervical spine who had undergone posterior cervical fixation using Nitinol shape memory alloy loop in the anterior-posterior combined approach. MATERIALS: Nine patients were surgically treated with anterior cervical fusion using an iliac bone graft and dynamic plate-screw system, and the posterior cervical fixation using Nitinol shape memory loop (Davydovtrade mark) at the same time. A retrospective review was performed. Clinical outcomes were assessed using the Frankel grading method. We reviewed the radiological parameters such as bony fusion rate, height of iliac bone graft strut, graft subsidence, cervical lordotic angle, and instrument related complication. RESULTS: Single-level fusion was performed in five patients, and two-level fusion in four. Solid bone fusion was presented in all cases after surgery. The mean height of graft strut was significantly decreased from 20.46+/-9.97 mm at immediate postoperative state to 18.87+/-8.60 mm at the final follow-up period (p<0.05). The mean cervical lordotic angle decreased from 13.83+/-11.84 degrees to 11.37+/-6.03 degrees at the immediate postoperative state but then, increased to 24.39+/-9.83 degrees at the final follow-up period (p<0.05). There were no instrument related complications. CONCLUSION: We suggest that the posterior cervical fixation using Nitinol shape memory alloy loop may be a simple and useful method, and be one of treatment options in anterior-posterior combined approach for the patients with the three column injury of the cervical spine.

Posterior Cervical Fixation with Nitinol Shape Memory Loop in the Anterior-Posterior Combined Approach for the Patients with Three Column Injury of the Cervical Spine : Preliminary Report

OBJECTIVE: The authors reviewed clinical and radiological outcomes in patients with three column injury of the cervical spine who had undergone posterior cervical fixation using Nitinol shape memory alloy loop in the anterior-posterior combined approach. MATERIALS: Nine patients were surgically treated with anterior cervical fusion using an iliac bone graft and dynamic plate-screw system, and the posterior cervical fixation using Nitinol shape memory loop (Davydov(TM)) at the same time. A retrospective review was performed. Clinical outcomes were assessed using the Frankel grading method. We reviewed the radiological parameters such as bony fusion rate, height of iliac bone graft strut, graft subsidence, cervical lordotic angle, and instrument related complication. RESULTS: Single-level fusion was performed in five patients, and two-level fusion in four. Solid bone fusion was presented in all cases after surgery. The mean height of graft strut was significantly decreased from 20.46+/-9.97 mm at immediate postoperative state to 18.87+/-8.60 mm at the final follow-up period (p<0.05). The mean cervical lordotic angle decreased from 13.83+/-11.84degrees to 11.37+/-6.03degrees at the immediate postoperative state but then, increased to 24.39+/-9.83degrees at the final follow-up period (p<0.05). There were no instrument related complications. CONCLUSION: We suggest that the posterior cervical fixation using Nitinol shape memory alloy loop may be a simple and useful method, and be one of treatment options in anterior-posterior combined approach for the patients with the three column injury of the cervical spine.