Comparison of the Efficacy of an Anchored Cage with Unidirectional and Bidirectional Screw Fixation in Single-Level Cervical Discectomy and Fusion Surgery.

AIM: To compare, and to analyze the clinical and radiological signs between bidirectional and unidirectional screw fixation in single level cervical discectomy and fusion surgery. MATERIAL AND METHODS: We retrospectively reviewed the data collected from 90 patients and divided them into the upper or lower spine fixation group (unidirectional) and the normal upper and lower spine fixation group (bidirectional). The patients' demographic data and preoperative and postoperative (24 months) clinical outcomes were collected. Pre- and postoperative (immediately and at 3, 6, 12, and 24 months) changes in the segmental angle in the operating field (SA), cervical lordosis, C2-7 sagittal vertical axis, and active disc height (aDH) were evaluated. We also compared the rate of fusion and muscle size change between the groups. RESULTS: The operation time in the bidirectional screw fixation group was significantly longer than that in the unidirectional screw fixation group ( > 6 min; p=0.03). There was no significant difference between the two groups in radiographic parameters before and immediately after surgery. From 3 months postoperatively, the unidirectional group had significantly higher SA and aDH than the bidirectional group (p=0.03). The fusion rate was higher in the bidirectional screw fixation group than in the unidirectional group, but this was not statistically significant (97% vs. 88%, p=0.07). CONCLUSION: The results of this study suggest that unidirectional screw fixation surgery can be useful as it has been associated with simple surgery, short surgery time, and maintenance of the lordotic curvature of SA and disc height.

Should cervicothoracic junctions be avoided in long cervical posterior fusion surgery? Analysis of clinical and radiologic outcomes over two years.

PURPOSE: This study aimed to confirm the usefulness of surgery that avoids the cervicothoracic junction (CTJ) by comparing the clinical and radiographic outcomes after posterior cervical fusion at C5/6 with those at C7/T1. METHODS: Patients who underwent laminectomy and posterior cervical instrument fusion for cervical spondylotic myelopathy (CSM) from 2012 to 2019 were retrospectively reviewed and divided according to whether the end level was at C5/6 (group 1) or C7/T1 (group 2). Demographic variables and incidence of distal junctional kyphosis (DJK) were compared between the groups. Clinical outcomes (visual analog scale [VAS] score for arm and neck pain and the Neck Disability Index value) and radiologic outcomes (T1 slope, cervical lordosis, segmental lordosis, C2-7 sagittal vertical axis, T1 slope-cervical lordosis mismatch) were compared over time. RESULTS: Sixty-seven patients were included. There were 32 patients in group 1 and 35 in group 2. The VAS score for neck pain was significantly lower in group 1 than in group 2 at 2 years after surgery (p = 0.03). The C2-7 sagittal vertical axis was significantly larger in group 2 than in group 1 at 1 year and 2 years postoperatively (p = 0.04). The incidence of DJK was higher in group 2 than in group 1 (28.57% vs 9.37%, p = 0.04). CONCLUSION: This study found that when CTJs are included in the posterior cervical long fusion surgery, although it would be better than preoperation, postoperative kyphosis and consequent neck pain may progress. The results of this study advocate the concept of avoiding CTJ fusion if possible.

A retrospective controlled study of postoperative fever after posterior lumbar interbody fusion due to degenerative lumbar disease.

BACKGROUND: Postoperative fever is a common feature of spinal surgery. When fever occurs postoperatively in patients, surgeons are eager to rule out an infection. There are many reports about postoperative fever and infection; however, only a few have described the relationship between degenerative spinal disease and postoperative fever. This study aimed to investigate the causes of postoperative fever in patients with degenerative lumbar disease undergoing posterior screw fixation and interbody fusion and compare patients with non-pathologic fever and infected febrile patients. METHODS: From March 2015 to February 2016, 263 patients with degenerative lumbar disease underwent posterior lumbar screw fixation and interbody fusion surgery in our institution. We performed risk factor analysis by categorizing patients as afebrile and febrile. Comparisons were made between afebrile patients and patients with non-pathologic fever, and an analysis was performed between patients with non-pathologic fever and patients with febrile infection. We compared each group by examining the demographic factors before surgery, surgery features, drain duration, and postoperative transfusion. The postoperative day (POD) of fever onset, postoperative fever duration, and blood sample results in patients with fever were investigated. RESULTS: The drain duration was found to be an important factor between the afebrile febrile groups and between the non-pathologic fever and afebrile groups. POD of fever occurred earlier in the non-pathologic group than in the infection group (p = 0.04), and the duration of fever was shorter in the non-pathologic fever group than in the infection group (p = 0.01). Higher procalcitonin levels were observed at POD 5 in the infection group than in the non-pathologic fever group. (p < 0.01) The accidental dural rupture rate was higher in the infected group (p = 0.02); this was thought to be caused by the long non-ambulatory period after surgery. CONCLUSION: This study identified risk factors and differences between infectious diseases associated with postoperative fever. A significant risk factor for postoperative non-pathological fever was a shorter catheter drainage period. Fever after 3 days, fever for more than 4 days and higher procalcitonin levels after surgery suggest infection.

Spinal Bony Involvement of IgG4-related Disease Treated by a Spondylectomy.

Immunoglobulin G4-related sclerosing disease (IgG4RD) is an emerging immune-mediated fibro-inflammatory disorder which can involve any organ. We describe the first IgG4-RD spondylitis treated with total en-bloc spondylectomy (TES). A 55-year-old man presented with back pain. Magnetic resonance imaging (MRI) of the thoracic spine revealed a pathologic compression fracture on T11 vertebral body and both pedicles suggestive of primary bone tumor or bone metastasis. We conducted TES of T11, because we could not exclude the possibility of primary bone tumor including giant cell tumor. Immunohistochemical examination of the pathology specimens from pleura around the pedicle demonstrated diffuse infiltration of IgG4-bearing plasma cells. Six weeks later from the surgery, a delayed serologic test was done and his serum IgG4 concentration was 45 mg/dL. The final diagnosis was probable IgG4RD on the basis of serological, imaging, histopathological findings. After 6 weeks of oral prednisolone treatment, patient's back pain improved dramatically. IgG4RD is very rare systemic disease and its paraspinal soft tissue like pleura involvement with vertebra body invasion was absent until now. Our experience indicated that surrounding soft tissue biopsy would be helpful when a percutaneous vertebra bone biopsy mismatched with the image studies, even though vertebra body was main pathological lesion considering the possibility of IgG4RD.

Comparison of Early Surgical Treatment With Conservative Treatment of Incomplete Cervical Spinal Cord Injury Without Major Fracture or Dislocation in Patients With Pre-existing Cervical Spinal Stenosis.

STUDY DESIGN: This was a retrospective comparative study. OBJECTIVE: The objective of this study was to evaluate the clinical outcomes of early surgical treatment (<24 h) and conservative treatment of incomplete cervical spinal cord injury (CSCI) without major fracture or dislocation in patients with pre-existing cervical spinal canal stenosis (CSCS). SUMMARY OF BACKGROUND DATA: The relative benefits of surgery, especially early surgical treatment, and conservative treatment for CSCI without major fracture or dislocation in patients with pre-existing CSCS remain unclear. Animal models of CSCI have demonstrated that early surgical decompression immediately after the initial insult may prevent or reverse secondary injury. However, the clinical outcomes of early surgery for incomplete CSCI in patients with pre-existing CSCS are still unclear. MATERIALS AND METHODS: The medical records and radiographic data of 54 patients admitted to our facility between 2005 and 2015 with American Spinal Injury Association (ASIA) impairment scale grade B or C and pre-existing CSCS without major fracture or dislocation were retrospectively reviewed. Thirty-three patients (mean age, 57.4±14.0 y) underwent early surgical treatment within 24 hours after initial trauma (S group), and 21 patients (mean age, 56.9±13.6 y) underwent conservative treatment (C group) performed by 2 spinal surgeons in accordance with their policies. The primary outcome was the degree of improvement in ASIA grade after 2 years. RESULTS: During the 2-year follow-up period, higher percentages of patients in the S group than in the C group showed ≥1 grade (90.9% vs. 57.1%, P=0.0051) and 2 grade (30.3% vs. 9.5%) improvements in ASIA grade. Multivariate analysis showed that treatment type, specifically early surgical treatment, was the only factor significantly associated with ASIA grade improvement after 2 years (P=0.0044). CONCLUSIONS: Early surgery yielded better neurological outcomes than conservative treatment in patients with incomplete CSCI without major fracture or dislocation and pre-existing CSCS. LEVEL OF EVIDENCE: Level III.

The Subaxial Cervical Pedicle Screw for Cervical Spine Diseases: The Review of Technical Developments and Complication Avoidance.

This study aimed to review information on the subaxial cervical pedicle screw (CPS) including recent anatomical considerations, entry points, placement techniques, accuracy, learning curve, and complications. Relevant literatures were reviewed, and the authors' experiences were summarized. The CPS is used for reconstruction of unstable cervical spine and achieves superior biomechanical stability compared to other fixation techniques. Various insertion and guidance techniques are established, among which, lateral fluoroscopy-assisted placement is the most common and cost-effective technique. Generally, placement under imaging guidance is more accurate than other techniques, and a three-dimensional template allows optimal trajectory for each pedicle regardless of intraoperative changes in spinal alignment. The free-hand technique using a curved pedicle probe without a funnel-like hole increases screw stability and reduces operation time, radiation exposure, and soft tissue injury. Compared to conventional lateral fluoroscopy-assisted placement, free-hand CPS placement by trained surgeons achieves superior accuracy comparable to that of image-guided navigation; in general, 30 training cases are sufficient for learning a safe and accurate technique for CPS placement. The complications of subaxial CPS are classified into three categories: complications due to screw misplacement, complications without screw misplacement, and others. Inexperienced surgeons may benefit from advanced techniques; however, the accuracy of CPS ultimately depends on the surgeon's experience. Inexperienced surgeons should master the placement of the thoracolumbar pedicle screw in real practice and practice CPS insertion using cadavers. During the initial phase of the learning curve, careful preparation of surgery, reiterated identification, patterned safety steps, and supervision of the expert are necessary.

Postoperative Non-Pathological Fever Following Posterior Cervical Fusion Surgery : Is Laminoplasty a Better Preventive Method than Laminectomy?

OBJECTIVE: To analyze the incidence and characteristics of delayed postoperative fever in posterior cervical fusion using cervical pedicle screws (CPS). METHODS: This study analyzed 119 patients who underwent posterior cervical fusion surgery using CPS. Delayed fever was defined as no fever for the first 3 postoperative days, followed by an ear temperature ≥38°C on postoperative day 4 and subsequent days. Patient age, sex, diagnosis, laminectomy, surgical level, revision status, body mass index, underlying medical disease, surgical duration, and transfusion status were retrospectively reviewed. RESULTS: Of 119 patients, seven were excluded due to surgical site infection, spondylitis, pneumonia, or surgical level that included the thoracic spine. Of the 112 included patients, 28 (25%) were febrile and 84 (75%) were afebrile. Multivariate logistic regression analysis showed that laminectomy was a statistically significant risk factor for postoperative non-pathological fever (odds ratio, 10.251; p=0.000). In contrast, trauma or tumor surgery and underlying medical disease were not significant risk factors for fever. CONCLUSION: Patients who develop delayed fever 4 days after posterior cervical fusion surgery using CPS are more likely to have non-pathologic fever than surgical site infection. Laminectomy is a significant risk factor for non-pathologic fever.

Accuracy Analysis of Iliac Screw Using Freehand Technique in Spinal Surgery : Relation between Screw Breach and Revision Surgery.

OBJECTIVE: To analyze the accuracy of iliac screws using freehand technique performed by the same surgeon. We also analyzed how the breach of iliac screws was related to the clinical symptoms resulting in revision surgery. METHODS: From January 2009 to November 2015, 100 patients (193 iliac screws) were analyzed using postoperative computed tomography scans. The breaches were classified based on the superior, inferior, lateral, and medial iliac wall violation by the screw. According to the length of screw extrusion, the classification grades were as follows : grade 1, screw extrusion <1 cm; grade II, 1 cm ≤ screw extrusion <2 cm; grade III, 2 cm ≤ screw extrusion <3 cm; and grade IV, 3 cm ≤ screw extrusion. We also reviewed the revision surgery associated with iliac screw misplacement. RESULTS: Of the 193 inserted screws, 169 were correctly located and 24 were misplaced screws. There were eight grade I, six grade II, six grade III, and four grade IV screw breaches, and 11, 8, 2, and 3 screws violated the medial, lateral, superior, and inferior walls, respectively. Four revision surgeries were performed for the grade III or IV iliac screw breaches in the lateral or inferior direction with respect to its related symptoms. CONCLUSION: In iliac screw placement, 12.4% breaches developed. Although most breaches were not problematic, symptomatic violations (2.1%) could result in revision surgery. Notably, the surgeon should keep in mind that lateral or inferior wall breaches longer than 2 cm can be risky and should be avoided.

Posterior Cervical Muscle-Preserving Interspinous Process Approach and Decompression: More Minimally Invasive and Modified Shiraishi's Selective Laminectomy.

OBJECTIVE: The cervical extensor musculature is important in cases of neck pain and loss of cervical lordosis after laminoplasty. Therefore, various surgical methods have been developed to preserve the muscle during laminoplasty. We have developed a posterior cervical muscle-preserving interspinous process (MIS) approach and decompression method. We have described the operation details and clinical outcomes of selected patients who have undergone this procedure. METHODS: The MIS approach and decompression method were performed in 20 consecutive patients who had only required central decompression for cervical stenosis. This procedure includes an approach to the interspinous space that is similar to Shiraishi's method but includes decompression without fracturing the spina bifida. RESULTS: The patients had no complications and did not require conversion to conventional laminoplasty. The mean operative time and mean blood loss was 53.0 minutes and 63.0 mL per level, respectively, and the mean hospital stay was 4.0 days. The mean preoperative and 3-month postoperative modified Japanese Orthopedic Association scores were 12.6 and 16.2, and the mean preoperative and 3-month postoperative neck disability index scores were 15.4 and 2.5, respectively. The postoperative neck visual analog scale score was 0.8. The mean preoperative and postoperative sagittal vertical axis was 1.6 and 1.8 cm, respectively. The mean loss of lordosis was 1.0°, and the mean cervical range of motion did not change from preoperatively to postoperatively. CONCLUSIONS: The MIS approach and decompression method was less invasive than both conventional laminoplasty and Shiraishi's selective laminectomy. It is a safe and effective minimally invasive technique for central stenosis caused by cervical spondylotic myelopathy.

Analysis of the Risk Factors for Unfavorable Radiologic Outcomes after Fusion Surgery in Thoracolumbar Burst Fracture : What Amount of Postoperative Thoracolumbar Kyphosis Correction is Reasonable?

OBJECTIVE: The aims in the management of thoracolumbar spinal fractures are not only to restore vertebral column stability, but also to obtain acceptable alignment of the thoracolumbar junction (T-L junction) to prevent complications. However, insufficient surgical correction of the thoracolumbar spine would be likely to cause late progression of abnormal kyphosis. Therefore, we identified the surgical factors that affected unfavorable radiologic outcomes of the thoracolumbar spine after surgery. METHODS: This study was conducted in a single institution from January 2007 to December 2013. A total of 98 patients with unstable thoracolumbar spine fracture were included. In these patients, fixation was done through transpedicular screws with rods by three surgical patterns. We reviewed digital radiographs and analyzed the images preoperatively and postoperatively during follow-up visits to compare the change of the thoracolumbar Cobb angle with radiologic parameters and clinical outcomes. The unfavorable radiologic group was defined as the patients who were measured as having greater than 20 degrees of thoracolumbar Cobb angle on the last follow-up, or who underwent kyphotic progression of thoracolumbar Cobb angle greater than 10 degrees from the immediate postoperative state to final follow-up, or who had overt instrument failure with/without additional surgery. We assessed the risk factors that affected the unfavorable radiologic outcomes. RESULTS: We had 43 patients with unfavorable radiologic outcomes, including 35 abnormal thoracolumbar alignments and 14 instrumental failures with/without additional surgery. The multivariate logistic regression test showed that immediate postoperative T-L junction Cobb angle less than 10.5 degrees was a statistically significant risk factor, as well as the presence of osteoporosis (p=0.017 and 0.049, respectively). CONCLUSION: Insufficient correction of thoracolumbar kyphosis was considered to be a major factor of an unfavorable radiological outcome. The spinal surgeon should consider that having a T-L junction Cobb angle larger than 10.5 degrees immediately after surgery could result in an unfavorable radiological outcome, which is related to a poor clinical outcome.

Implementation of Targeted Temperature Management in a Patient with Cerebral Arterial Gas Embolism.

Cerebral arterial gas embolism (CAGE) shows various manifestations according to the quantity of gas and the brain areas affected. The symptoms range from minor motor weakness, headache, and confusion to disorientation, convulsions, hemiparesis, unconsciousness, and coma. A 46-year-old man was transferred to our emergency department due to altered sensorium. Immediately after a controlled ascent from 33 m of seawater, he complained of shortness of breath and rigid extremities, lapsing into unconsciousness. He was intubated at another medical center, where a brain computerized axial tomography scan showed no definitive abnormal findings. Pneumothorax and obstructing lesions were apparent in the left thorax of the computed tomography scan. Following closed thoracostomy, we provided hyperbaric oxygen therapy (HBOT) using U.S. Navy Treatment Table (USN TT) 6A. A brain magnetic resonance imaging diffusion image taken after HBOT showed acute infarction in both middle and posterior cerebral arteries. We implemented targeted temperature management (TTM) to prevent worsening of cerebral function in the intensive care unit. After completing TTM, we repeated HBOT using USN TT5 and started rehabilitation therapy. He fully recovered from the neurological deficits. This is the first case of CAGE treated with TTM and consecutive HBOTs suggesting that TTM might facilitate salvage of the penumbra in severe CAGE.

Postoperative Nonpathologic Fever After Spinal Surgery: Incidence and Risk Factor Analysis.

BACKGROUND: Although there are many postoperative febrile causes, surgical-site infection has always been considered as one of the major causes, but it should be excluded; we encountered many patients who showed delayed postoperative fever that was not related to wound infection after spinal surgery. We aimed to determine the incidence of delayed postoperative fever and its characteristics after spinal surgery, and to analyze the causal factors. METHODS: A total of 250 patients who underwent any type of spinal surgery were analyzed. We determined febrile patients as those who did not show any fever until postoperative day 3, and those who showed a fever with an ear temperature of greater than 37.8°C at 4 days after surgery. We collected patient data including age, sex, coexistence of diabetes mellitus or hypertension, smoking history, location of surgical lesion (e.g., cervical, thoracic, lumbar spine), type of surgery, surgical approach, diagnosis, surgical level, presence of revision surgery, operative time, duration of administration of prophylactic antibiotics, and the presence of transfusion during the perioperative period, with a chart review. RESULTS: There were 33 febrile patients and 217 afebrile patients. Multivariate logistic regression showed that surgical approach (i.e., posterior approach with anterior body removal and mesh graft insertion), trauma and tumor surgery compared with degenerative disease, and long duration of surgery were statistically significant risk factors for postoperative nonpathologic fever. CONCLUSIONS: We suggest that most spinal surgeons should be aware that postoperative fever can be common without a wound infection, despite its appearance during the late acute or subacute period.

Feasibility of Posterior Cervical Foraminotomy in Cervical Foraminal Stenosis: Prediction of Surgical Outcomes by the Foraminal Shape on Preoperative Computed Tomography.

STUDY DESIGN: A retrospective cohort study. OBJECTIVE: The aim of this study was to compare the feasibility of posterior cervical laminoforaminotomy (PCF) for V- or parallel-shaped foraminal stenosis (FS). SUMMARY OF BACKGROUND DATA: During PCF, the need for extensive facet resection would depend on the extent of any pathology. When resection is extensive, the possibilities of instability and incomplete decompression should be considered. METHODS: From March 2004 to March 2015, we enrolled 36 patients following single-level PCF procedures for FS. We classified patients by foraminal shape on preoperative computed tomography (CT) scan into V-shaped and parallel-shaped groups. We then compared arm and neck pain using a numeric rating scale (NRS) and clinical outcomes using Odom criteria. Radiological evaluation included dynamic X-rays for instability and CT scans for facet resection. RESULT: We enrolled 16 and 20 patients in the V-shape and parallel-shape groups, respectively. By Odom criteria, no patient was graded fair or poor in the V group, but five patients were graded as fair and one patient as poor in the parallel group. Continued postoperative arm pain at 1 year, which was related to incomplete decompression, was significantly higher in parallel group. Only one patient complained of postoperative neck pain with an NRS >5, and another five patients sustained radiculopathy with an NRS >5. Among five patients who complained sustained radiculopathy, one patient required revision surgery for incomplete decompression. The amount of facet removal was not different significantly between groups, and no patient had postoperative instability. CONCLUSION: Although PCF seems to be a good surgical option for V-shaped FS, we experienced worse outcomes for patients with parallel-shaped FS. We recommend that ACDF or more aggressive posterior foraminotomy be performed with fusion when presented with parallel neuroforaminal compression. LEVEL OF EVIDENCE: 4.

An Assessment of the Medial Angle of Inserted Subaxial Cervical Pedicle Screw during Surgery: Practical Use of Preoperative CT Scanning and Intraoperative X-rays.

The most important factor for cervical pedicle screw placement (CPS) is creating a sufficient medial angle. We aimed to know the medial angle of the inserted subaxial CPS during surgery using intraoperative AP X-rays. From March 2012 to September 2014, we performed posterior cervical fusions using CPS on 75 patients, including a total of 389 CPS insertions. Using preoperative CT scanning, we determined the θlat (i.e., an angle between a vertical line and a line to connect the planned entry point and the axial middle point of the pedicle) and θmed (i.e., an angle between a vertical line and a line to connect a new medial entry point and the axial middle point of the pedicle; this angle was regarded as minimally acceptable and a safe medial angle). The actual inserted medial angle (θins) was checked and we determined whether it was between the θmed and θlat in the accurately placed CPS, and not in the laterally violated CPS. We measured the horizontal distance of the CPS body (l; using an intraoperative AP X-ray). If the actual screw length (L) was known, we could calculate the medial angle (θAP) as sin-1 l / L. We checked the θAP and θins for all of the same levels. Intra- and inter-observer agreement was analyzed. Among 368 accurately inserted CPSs, we found that 360 of the θins values were greater than or equal to the θmed on the same level (P <0.001). The intra-observer agreements were 0.781 and 0.847. The inter-observer agreements were 0.917 and 0.949. It was important that θins was greater than or equal to the θmed. Our suggested formula, θAP = sin-1 l / L, seems to be useful for predicting the medial angle of the inserted CPS and for comparing it with θmed during surgery based on an AP X-ray and preoperative CT scan.

Analysis of the Fusion and Graft Resorption Rates, as Measured by Computed Tomography, 1 Year After Posterior Cervical Fusion Using a Cervical Pedicle Screw.

BACKGROUND: We previously showed that cervical pedicle screw (CPS) placement is safe even with the freehand technique. The posterolateral fusion rate 1 year after CPS placement, as measured by computed tomography (CT), is reported here. The graft resorption rates when different graft materials were used were also analyzed. METHODS: Between 2012 and 2015, 93 patients underwent posterior cervical fusion surgery with the CPS from C2 to C7. Of these patients, 56 consented to CT scans immediately and 1 year after surgery. These patients formed the present study group. The patients were categorized according to whether the graft material was local bone, allograft, or a mixture. Graft volume was measured at both CT scans. Graft resorption rate was determined by comparing the 2 scans. Radiologic fusion was assessed on the 1 year postoperative CT scan and radiography. RESULTS: The reason for surgery was trauma (n = 19), degenerative disease (n = 35), tumor (n = 1), and spondylitis (n = 1). Surgery was performed with CPS fixation and decompression. Even although iliac bone grafting was not performed, the overall fusion rate was 98.2% (55/56). The single fusion failure case received a mixture of local bone and allograft. Although the allograft group showed the greatest graft resorption rate (91.5%), all patients in this group had a bony bridge that crossed the facet joint on the 1 year CT scan. CONCLUSIONS: CPS placement yielded a posterolateral cervical fusion rate of 98.2%. Despite the high resorption rate of allograft only, this material yielded fusion rates that were similar to those of the other materials. Thus, the strong fixation power of CPS might compensate for the delayed fusion and high resorption rates of allograft bone chips.