OBJECTIVE: To review the clinical characteristics of patients with traumatic spinopelvic dissociation (SPD) and explore the diagnostic and therapeutic methods. METHODS: A clinical data of 22 patients with SPD who underwent surgical treatment between March 2019 and August 2024 was retrospectively analyzed. There were 13 males and 9 females, with an average age of 35.5 years (range, 14-61 years). The causes of injury included falling from height in 16 cases, traffic accidents in 5 cases, and compression injury in 1 case. Sacral fractures were classified based on morphology into "U" type (9 cases), "H" type (7 cases), "T" type (4 cases), and "λ" type (2 cases). According to the Roy-Camille classification, there were 4 cases of type Ⅰ, 12 cases of type Ⅱ, 2 cases of type Ⅲ, and 4 cases of type Ⅳ. The Cobb angle was (35.7± 22.0)°. Sixteen patients were accompanied by lumbosacral trunk and cauda equina nerve injury, which was classified as grade Ⅱ in 5 cases, grade Ⅲ in 5 cases, and grade Ⅳ in 6 cases according to the Gibbons grading. The time from injury to operation was 2-17 days (mean, 5.7 days). Based on the type of sacral fracture and sacral nerve injury, 6 cases were treated with closed reduction and minimally invasive percutaneous sacroiliac screw fixation, 16 cases were treated with open reduction and lumbar iliac fixation (8 cases)/triangular fixation (8 cases). Among them, 11 patients with severe fracture displacement and kyphotic deformity leading to sacral canal stenosis or bony impingement within the sacral foramen underwent laminectomy and sacral nerve decompression. X-ray films and CT were reviewed during followed-up. The Matta score was used to evaluate the quality of fracture reduction. At last follow-up, the Majeed score was used to assess the functional recovery, and the Gibbons grading was used to evaluate the nerve function. RESULTS: All operations were successfully completed. All patients were followed up 8-64 months (mean, 20.4 months). Two patients developed deep vein thrombosis of the lower limbs, 2 had incision infections, and 1 developed a sacral pressure ulcer; no other complications occurred. Radiological examination showed that the Cobb angle was (12.0±6.8)°, which was significantly different from the preoperative one ( t=6.000, P<0.001). The Cobb angle in 16 patients who underwent open reduction was (14.9±5.5)°, which was significantly different from the preoperative one [(46.8±13.9)° ] ( t=8.684, P<0.001). According to the Matta scoring criteria, the quality of fracture reduction was rated as excellent in 8 cases, good in 7 cases, fair in 5 cases, and poor in 2 cases, with an excellent and good rate of 68.2%. Bone callus formation was observed at the fracture site in all patients at 12 weeks after operation, and bony union achieved in all cases at last follow-up, with a healing time ranging from 12 to 36 weeks (mean, 17.6 weeks). At last follow-up, the Majeed score was rated as excellent in 7 cases, good in 10 cases, fair in 4 cases, and poor in 1 case, with an excellent and good rate of 77.3%. One patient experienced a unilateral iliac screw breakage at 12 months after operation, but the fracture had already healed, and there was no loss of reduction. Among the 16 patients with preoperative sacral nerve injury, 11 cases showed improvement in nerve function (6 cases) or recovery (5 cases). CONCLUSION SPD with low incidence, multiple associated injuries, and high incidence of sacral nerve injury, requires timely decompression of the sacral canal for symptomatic sacral nerve compression, fractures reduction, deformities correction, and stable fixation.
Humans ; Adult ; Female ; Male ; Retrospective Studies ; Middle Aged ; Spinal Fractures/diagnostic imaging* ; Adolescent ; Sacrum/diagnostic imaging* ; Fracture Fixation, Internal/methods* ; Young Adult ; Pelvic Bones/surgery* ; Treatment Outcome ; Bone Screws

PURPOSE: The fixation method commonly employed worldwide for treating unstable fractures of the posterior pelvic ring is the percutaneous iliosacral screw technique. However, prolonged operation time and frequent fluoroscopies result in surgical risks. This study aimed to investigate whether a new triangulation method could reduce operative and fluoroscopy times and increase the accuracy of screw placement. METHODS: This study is a real-world retrospective cohort analysis that examined a patient cohort who underwent percutaneous iliosacral screw fixation between January 1, 2019 and December 31, 2022. Inclusion criteria were patients (1) diagnosed with posterior pelvic ring instability who underwent pelvic fracture closed reduction and percutaneous S1 transverse-penetrating iliosacral screw placement and (2) aged >18 years. Exclusion criteria were: (1) combined proximal femoral fractures, (2) severe soft tissue injury in the surgical area, (3) incomplete imaging data, and (4) declining to provide written informed consent by the patient. The patients were divided into 2 groups according to the screw insertion method: conventional and triangulation methods. Screw placement and fluoroscopy times recorded by the C-arm were compared between the 2 methods. The accuracy of screw placement was evaluated by Smith grading on postoperative CT. Normality tests were conducted to assess the distribution of the quantitative variables and the Chi-square test was used to compare the qualitative variables. RESULTS: The study included a total of 94 patients diagnosed with posterior pelvic ring instability, who underwent percutaneous iliosacral screw placement. The patients were divided into 2 groups: 46 patients treated with the conventional surgical method and 48 patients received the triangulation method. The operation time (61.13±9.69 vs. 35.77±6.27) min and fluoroscopy frequency times (52.15±9.29 vs. 24.40±4.04) of the triangulation method were significantly reduced (p<0.001). CONCLUSIONS The use of a triangular positioning technique for the surface positioning of percutaneous iliosacral screws could reduce the operative time and fluoroscopy frequency. And the screw placement accuracy using this new method was comparable to that using other conventional methods.
Humans ; Retrospective Studies ; Bone Screws ; Pelvic Bones/surgery* ; Male ; Female ; Fracture Fixation, Internal/methods* ; Fractures, Bone/surgery* ; Adult ; Middle Aged ; Fluoroscopy ; Aged ; Sacrum/surgery* ; Operative Time

OBJECTIVE: To precise classify sacral meningeal cysts, effective guide minimally invasive neurosurgery and postoperative personalized rehabilitation by multiple dimensions radiographic reconstruction MRI. METHODS: From March to December 2021, based on the original 3D-fast imaging employing steadystate acquisition (FIESTA) scanning sequence, 92 patients with sacral meningeal cysts were pre-operatively evaluated by multiple dimensional reconstruction MRI. The shape of nerve root and the leakage of cyst were reconstructed according to the direction of nerve root or leakage track showed on original MRI scans. Sacral canal cysts were accurately classified as including nerve root and without nerve root, so as to accurately design the incision of skin and formulate corresponding open range of the posterior wall of the sacral canal. Under the microscope intraoperation, the shape of the nerve roots inside cysts or leakage track of the cysts without nerve roots were verified and explored. After the reinforcement and shaping operation, several reexaminations of multiple dimensional reconstruction MRI were performed to understand the deformation of the nerve root and hydrops in the operation cavity, so as to formulate a persona-lized rehabilitation plan for the patients. RESULTS: Among the 92 patients with sacral mengingeal cyst, 58 (63.0%) cysts with nerve root cyst, 29 (31.5%) cysts without nerve root cyst, and 5 (5.4%) cysts with mixed sacral canal cyst. In 58 patients with nerve root cysts, the accuracy of preoperative clinical classification on MRI image reached 96.6% (56/58) through confirmation by operating microscope. Only 2 cases of large single cyst with nerve root on the head of cyst were mistaken for without nerve root type. In 29 patients with sacral cyst without nerve root, the accuracy of preoperative image reached 100% through confirmation by operating microscope. The accuracy of judging the internal nerve root and leakage of 12 cases with recurrent sacral cyst was also 100%. Two cases of delayed postoperative hydrops were found one month after operation. After rehabilitation treatment by moxibustion and bathing, the hydrops disappeared 4-6 months after operation. CONCLUSION Multiple dimensional reconstruction MRI can precisely make clinical classification of sacral meningeal cysts before operation, guide minimally invasive neurosurgery effectively, and improve the rehabilitation effect.
Humans ; Magnetic Resonance Imaging/methods* ; Male ; Female ; Sacrum/surgery* ; Adult ; Middle Aged ; Imaging, Three-Dimensional/methods* ; Cysts/rehabilitation* ; Aged ; Adolescent ; Young Adult ; Spinal Nerve Roots/diagnostic imaging* ; Minimally Invasive Surgical Procedures ; Neurosurgical Procedures/methods*

OBJECTIVE: To analyze the safety and effectiveness of 3D printing prefabricated nail path model assisted lumbosacral hemivertebra orthopaedic surgery. METHODS: A retrospective analysis was performed on 8 patients with lumbosacral hemivertebra deformity admitted from January 2016 to July 2021, including 3 males and 5 females, aged 6 to 15 at the time of surgery. The hemivertebra of 4 cases located on the left side and 4 cases on the right side. The hemivertebra of 1 case located at L_2,3, 2 cases at L_3,4, 2 cases at L_4,5, and 3 cases at L₅S₁. Four cases were fully segmented hemivertebra and 4 cases were incomplete segmented hemivertebra. The patient CT data was imported into Mimics 21.0 software for modeling, and then the model data was imported into 3-Matic software. The vertebra requiring screw placement was selected to simulate the optimal screw placement angle and length, and the model was printed for preoperative planning and intraoperative guidance. All patients underwent orthopedic surgery with the aid of 3D printing preset nail path model. The safety and effectiveness of the 3D printing prefabricated nail tunnel model assisted lumbosacral hemivertebra orthopaedic surgery was evaluated by comparing the imaging parameters of the patients. The main outcome measures were the Cobb angle of the main curve, the Cobb angle of the proximal compensatory curve, the coronal balance index C₇ plumb line-center sacral vertical line(C₇PL-CSVL), the accuracy of nail placement, and the correction rate of scoliosis before surgery, 1 week and 1 year after surgery. RESULTS: All of 8 patients were followed up for 13 to 31 months. A total of 98 pedicle screws were placed in 8 patients. The number of pedicle screw grades A, B, C, D, E was 38, 46, 10, 4, 0 screws. The screws of grade A and B were defined as good position, the accuracy rate of screw placement was 85.7%. The Cobb angle of the main curve were 21° to 38° before operation, 5° to 11° at 1 week after operation, 7°to 12° at 1 year after operation. The Cobb angle of the proximal compensatory curve were 16° to 39° befoer operation, 7° to 12 °at 1 week after operation, 7° to 14° at 1 year after operation, the correction effect remained good with no correction loss. The coronal balance index C7PL-CSVL were 20 to 35 mm before operation, 11 to 18 mm at 1 week after operation, 10 to 16 mm at 1 year after operation, the coronal imbalance improved. The scoliosis correction rate was 65.6% to 84.2% 1 week after surgery, and 61.9% to 81.6% 1 year after surgery. CONCLUSION The use of 3D printing prefixed nail tunnel model in lumbosacral hemivertebra osteotomy is safe and effective, and can significantly improve patients' local deformities. It is a reliable method to assist lumbar sacral hemivertebra osteotomy.
Humans ; Printing, Three-Dimensional ; Female ; Male ; Adolescent ; Retrospective Studies ; Child ; Lumbar Vertebrae/surgery* ; Sacrum/abnormalities* ; Bone Nails ; Orthopedic Procedures/instrumentation*

OBJECTIVE: To explore the trend of changes in the parameters of the spine-pelvic sagittal plane before and after surgery in patients with double-segment lumbar spondylolisthesis (LSL) and to evaluate the value of the surgical effect. METHODS: A retrospective analysis of 95 double-segment lumbar spondylolisthesis patients treated with posterior lumbar interbody fusion from October 2019 to October 2020 were analyzed, including 31 males and 64 females;age ranging from 41 to 63 years old, with an average of (52.10±4.35) years old;degree of lesion, 47 patients with gradeⅠand 48 patients with gradeⅡ. The surgical efficacy was evaluated according to the Oswestry dysfunction index(ODI) improvement rate at 3 months after operation. ODI improvement rate ≥50% was considered good, and <50% was considered bad. Ninety-five patients were divided into good curative effect group (74 cases) and poor curative effect group (21 cases) according to surgical curative effect. The clinical data, such as gender, age, body mass index, course of disease, degree of disease, operation time, intraoperative blood loss, and comorbidities were compared between two groups were compared. The parameters of spine pelvis sagittal plane were observed before and 3 months after operation, including spine sacral angle (SSA), T1 pelvic angle (TPA), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS). Clinical symptoms were evaluated using visual analogue scale (VAS) and ODI. The correlation between the changes of spine pelvis sagittal plane parameters and the changes of VAS and ODI before and after surgery were analyzed, and the value of spine pelvis sagittal plane parameters in evaluating the surgical efficacy of patients with double level lumbar spondylolisthesis at 3 months after surgery was evaluated. RESULTS: The courses of disease and surgical time in the group with poor efficacy were longer than those in the group with good efficacy, and the degree of lesion was higher in the group with poor efficacy (P<0.05). The SSA, TPA, LL, and SS of the group with good efficacy were higher than those of the group with poor efficacy before and 3 months after surgery, while the PT was lower than that of the group with poor efficacy (P<0.05). The changes in SSA, TPA, LL, PT, and SS before and after surgery in the group with good efficacy were greater than those in the group with poor efficacy (P<0.05). The VAS and ODI of both groups were lower at 3 months after surgery than before, and the group with good efficacy was lower(P<0.05). The changes in VAS and ODI before and after surgery in the group with good efficacy were greater than those in the group with poor efficacy (P<0.05). The changes in SSA, TPA, LL, PT, SS before and after surgery were positively correlated with the changes in VAS and ODI (P<0.05). Three months after surgery, SSA, TPA, LL, PT, and SS were used to evaluate the surgical efficacy of patients with dual level lumbar spondylolisthesis. The area under the curve (AUC) was 0.868, 0.797, 0.875, 0.822, and 0.853, respectively. The combined evaluation of all indicators resulted in the highest AUC, 0.927, and the best sensitivity and specificity were 90.50% and 91.89%, respectively. CONCLUSION The spine pelvis sagittal plane parameters SSA, TPA, LL, and SS of patients with double level lumbar spondylolisthesis before and after surgery show an upward trend;PT shows a downward trend;PI do not change significantly. And the changes of SSA, TPA, LL, SS, and PT are closely related to the patient's pain level and the improvement of lumbar function, which can be used as parameters to evaluate the surgical efficacy.
Female ; Animals ; Male ; Humans ; Adult ; Middle Aged ; Spondylolisthesis/surgery* ; Retrospective Studies ; Sacrum ; Blood Loss, Surgical ; Body Mass Index

OBJECTIVE: To evaluate the feasibility of S₂ alar iliac screw insertion in Chinese children using computerized three-dimension reconstruction and simulated screw placement technique, and to optimize the measurement of screw parameters. METHODS: A total of 83 pelvic CT data of children who underwent pelvic CT scan December 2018 to December 2020 were retrospectively analyzed, excluding fractures, deformities, and tumors. There were 44 boys and 39 girls, with an average age of (10.66±3.52) years, and were divided into 4 groups based on age (group A:5 to 7 years old;group B:8 to 10 years old;group C:11-13 years old;group D:14 to 16 years old). The original CT data obtained were imported into Mimics software, and the bony structure of the pelvis was reconstructed, and the maximum and minimum cranial angles of the screws were simulated in the three-dimensional view with the placement of 6.5 mm diameter S2 alar iliac screws. Subsequently, the coronal angle, sagittal angle, transverse angle, total length of the screw, length of the screw in the sacrum, width of the iliac, and distance of the entry point from the skin were measured in 3-Matic software at the maximum and minimum head tilt angles, respectively. The differences among the screw parameters of S₂ alar iliac screws in children of different ages and the differences between gender and side were compared and analyzed. RESULTS: In all 83 children, 6.5 mm diameter S₂ iliac screws could be placed. There was no significant difference between the side of each screw placement parameter. The 5 to 7 years old children had a significantly smaller screw coronal angle than other age groups, but in the screw sagittal angle, the difference was more mixed. The 5 to 7 years old children could obtain a larger angle at the maximum head tilt angle of the screw, but at the minimum cranial angle, the larger angle was obtained in the age group of 11 to 13 years old. There were no significant differences among the age groups. The coronal angle and sagittal angle under maximum cephalic angle and minimum cranial angle of 5 to 7 years old male were (40.91±2.91)° and (51.85±3.75)° respectively, which were significantly greater than in female. The coronal angle under minimum cranial angle was significantly greater in girls aged 8-10 years old than in boys. For the remaining screw placement angle parameters, there were no significant differences between gender. The differences in the minimum iliac width, the screw length, and the length of the sacral screws showed an increasing trend with age in all age groups. The distance from the screw entry point to the skin in boys were significantly smaller than that of girls. The minimum width of the iliac in boys at 14 to 16 years of age were significantly wider than that in girls at the same stage. In contrast, in girls aged 5 to 7 years and 11 to 13 years, the screw length was significantly longer than that of boys at the same stage. CONCLUSION The pelvis of children aged 5 to 16 years can safely accommodate the placement of 6.5 mm diameter S₂ alar iliac screws, but the bony structures of the pelvis are developing and growing in children, precise assessment is needed to plan a reasonable screw trajectory and select the appropriate screw length.
Humans ; Male ; Female ; Child ; Adolescent ; Child, Preschool ; Ilium/surgery* ; Retrospective Studies ; Feasibility Studies ; Bone Screws ; Pelvis ; Sacrum/surgery* ; Spinal Fusion/methods*

OBJECTIVE: To observe the efficacy and complications of one-stage tumor resection to treat primary sacral neurogenic tumors and to discuss some details in the clinically relevant anatomy. METHODS: A retrospective analysis of 26 patients with neurogenic turors of the sacral spine who were surgically treated from January 2001 to January 2018, including 16 males and 10 females, aged from 21 to 69 years old with an average age of (39.3±10.9) years old. The courses of diseases ranged from 3 to 56 months with an average of (17.9±10.1) months. The diameters of presacral components ranged from 3.3 to 19.6 cm with an average of (8.7±4.1) cm. The proximal margin of presacral lesions was above the L₅S₁ level in 6 cases, and lower than L₅S₁ in 20 cases. A posterior incision approach for one-stage complete resection of the tumor was used firstly, and an anterior approach was combined when necessary. Spinal-pelvic reconstruction with the modified Galveston technique was also carried out in relevant cases. Whether to preserve the tumor-involved nerve roots depended on the situation during the operation. The operation time, intraoperative blood loss, pain relief, and complications were recorded. The lumbosacral spine stability and sacral plexus neurological function were evaluated during postoperative follow-up, and local recurrence and distant metastasis were examined as well. RESULTS: Total excision was achieved in all 26 patients, with an operation time of (160.4±35.3) mins and an intraoperative blood loss of (1 092.3±568.8) ml. Tumors have been removed via a posterior-only approach in 21 cases and via combined anterior/posterior approaches in 5 cases. The diameter of presacral masses components ranged from 11.3 to 19.6 cm with an average of (15.1±3.2) cm in patients with combined anterior/posterior approaches, and ranged from 3.3 to 10.9 cm with an average of (7.2±2.4) cm in patients with a posterior-only approach. Five of the six patients whose proximal margin of presacral masses was above the L₅S₁ level adopted combined anterior/posterior approaches, and 20 patients lower than the L₅S₁ level adopted the posterior-only approach. All the patients were followed up for 6 to 82 months with an average of(45.4±18.2)months. Postoperative lumbosacral pain and lower extremity radicular pain were significantly relieved, and sensation, muscle strength and bowel and bladder function were also improved to varying degrees. The postoperative early complications included superficial wound infection in 1 case and cerebrospinal fluid leakage in 2 cases. Pathology confirmed 17 cases of schwannoma, 7 cases of neurofibroma and 2 cases of malignant schwannoma. Local recurrence was observed in two cases of benign neurogenic tumors. One patient with a malignant nerve sheath tumor had lung metastasis, who died 20 months after the operation. In 17 cases of upper sacral neurogenic tumors, 4 cases did not undergo spinal-pelvic reconstruction with internal fixation, of which 2 cases suffered from postoperative segmental instability. Tumor-involved nerve roots were resected during surgery in 7 cases. One of these patients who had S₂ and S₃ nerve roots sacrificed simultaneously had an impaired bladder and bowel function postoperatively, and did not recover completely. In the other 6 cases, the neurological function was not damaged obviously or recovered well. CONCLUSION The posterior approach can directly expose the lesions, and it is also convenient to deal with nerve roots and blood vessels. The operation time, intraoperative blood loss, degree of symptom relief, complication rate, and recurrence and metastasis rate can be controlled at an appropriate level. It is a safe and effective surgical approach. When the upper edge of the presacral mass is higher than the L₅S₁ level or the diameter of the presacral mass exceeds 10 cm, an additional anterior approach should be considered. The stress between the spine and pelvis is high, and internal fixation should be used to restore the mechanical continuity of the spine and pelvis during resection of neurogenic tumors of the high sacral spine. Most of the parent nerve roots have lost their function. Resection of a single parent nerve root is unlikely to cause severe neurological dysfunction, while the adjacent nerve roots have compensatory functions and should be preserved as much as possible during surgery.
Adult ; Aged ; Blood Loss, Surgical ; Female ; Humans ; Male ; Middle Aged ; Pain/pathology* ; Postoperative Complications/pathology* ; Retrospective Studies ; Sacrum/surgery* ; Treatment Outcome ; Young Adult

OBJECTIVE: To evaluate the efficacy of iliolumbar fixation in the treatment of U-shaped sacral fractures. METHODS: A retrospective study was conducted on the 14 complex U-shaped sacral fractures which had been treated from January 2014 to December 2019, involved 10 males and 4 females, aged 24 to 48 (35.4±6.5) years. Fracture healing time, nerve function, clinical function and complications were observed in the patients. RESULTS: All patients were followed up for 9 to 16(26.0±5.9) months. The complete weight-bearing time for bone healing was(12.4±2.0) weeks. One case of surgical incision infection occurred after operation, and one case of sacrum nailspenetrated to the outer plate of sacrum. No complications such as pressure ulcers, loosening or rupture of internal fixation occurred. According to Gibbons scoring, the neurological function recovered from preoperative 2.9±0.9 to postoperative 2.1±1.1, there were statistically significant differences between preoperative and postoperative ( CONCLUSION Sacral lumbar fixation is an effective method for the treatment of U-shaped sacrum fractures. It has the advantages of strong internal fixation and satisfactory functional recovery.
Bone Screws ; Female ; Fracture Fixation, Internal ; Humans ; Male ; Retrospective Studies ; Sacrum/surgery* ; Spinal Fractures/surgery* ; Treatment Outcome

Finite element method (FEM) was used to investigate the biomechanical properties of three types of surgical fixations of U-shaped sacral fractures. Based on a previously established and validated complete lumbar-pelvic model, three models of surgical fixations of U-shaped sacral fractures were established: ① S1S2 passed through screw (S1S2), ② L4-L5 pedicle screw + screw for wing of ilium (L4L5 + IS), and ③ L4-L5 pedicle screw + S1 passed through screw + screw for wing of ilium (L4L5 + S1 + IS). A 400 N force acting vertically downward, along with torque of 7.5 N·m in different directions (anterior flexion, posterior extension, axial rotation, and axial lateral bending), was exerted on the upper surface of L4. Comparisons were made on differences in separation of the fracture gap and maximum stress in sitting and standing positions among three fixation methods. This study showed that: for values of separation of the fracture gap produced by different operation groups in different positions, L4L5 + S1 + IS was far less than L4L5 + IS and S1S2. For internal fixators, the maximum stress value produced was: L4L5 + IS > L4L5 + S1 + IS > S1S2. For the intervertebral disc, the maximum stress value produced by S1S2 is much larger than that of L4L5 + S1 + IS and L4L5 + IS. In a comprehensive consideration, L4L5 + S1 + IS could be prioritized for fixation of U-shaped sacral fractures. The objective of this research is to compare the biomechanical differences of three different internal fixation methods for U-shaped sacral fractures, for the reference of clinical operation.
Biomechanical Phenomena ; Finite Element Analysis ; Fracture Fixation ; methods ; Humans ; Lumbar Vertebrae ; Pedicle Screws ; Sacrum ; injuries ; Spinal Fractures ; surgery ; Spinal Fusion

BACKGROUNDResection of sacral chordomas is challenging. The anatomy is complex, and there are often no bony landmarks to guide the resection. Achieving adequate surgical margins is, therefore, difficult, and the recurrence rate is high. Use of computer navigation may allow optimal preoperative planning and improve precision in tumor resection. The purpose of this study was to evaluate the safety and feasibility of computer navigation-aided resection of sacral chordomas.

METHODSBetween 2007 and 2013, a total of 26 patients with sacral chordoma underwent computer navigation-aided surgery were included and followed for a minimum of 18 months. There were 21 primary cases and 5 recurrent cases, with a mean age of 55.8 years old (range: 35-84 years old). Tumors were located above the level of the S3 neural foramen in 23 patients and below the level of the S3 neural foramen in 3 patients. Three-dimensional images were reconstructed with a computed tomography-based navigation system combined with the magnetic resonance images using the navigation software. Tumors were resected via a posterior approach assisted by the computer navigation. Mean follow-up was 38.6 months (range: 18-84 months).

RESULTSMean operative time was 307 min. Mean intraoperative blood loss was 3065 ml. For computer navigation, the mean registration deviation during surgery was 1.7 mm. There were 18 wide resections, 4 marginal resections, and 4 intralesional resections. All patients were alive at the final follow-up, with 2 (7.7%) exhibiting tumor recurrence. The other 24 patients were tumor-free. The mean Musculoskeletal Tumor Society Score was 27.3 (range: 19-30).

CONCLUSIONSComputer-assisted navigation can be safely applied to the resection of the sacral chordomas, allowing execution of preoperative plans, and achieving good oncological outcomes. Nevertheless, this needs to be accomplished by surgeons with adequate experience and skill.

Adult ; Aged ; Aged, 80 and over ; Chordoma ; surgery ; Female ; Humans ; Imaging, Three-Dimensional ; Male ; Middle Aged ; Sacrum ; surgery ; Spinal Neoplasms ; surgery ; Surgery, Computer-Assisted ; methods ; Treatment Outcome