Objective To review the development of the reconstruction methods following total sacrectomy, and to provide reference for finding a better reconstruction method following total sacrectomy. Methods The case reports and biomechanical and finite element studies of reconstruction following total sacrectomy at home and abroad were searched. Development and current situation were summarized. Results After developing for nearly 30 years, great progress has been made in the reconstruction concept and fixation techniques. The fixation methods can be summarized as the following three strategies: spinopelvic fixation (SPF), posterior pelvic ring fixation (PPRF), and anterior spinal column fixation (ASCF). SPF has undergone technical progress from intrapelvic rod and hook constructs to pedicle and iliac screw-rod systems. PPRF and ASCF could improve the stability of the reconstruction system. Conclusion Reconstruction following total sacrectomy remains a challenge. Reconstruction combining SPF, PPRF, and ASCF is the developmental direction to achieve mechanical stability. How to gain biological fixation to improve the long-term stability is an urgent problem to be solved.
Objective To biomechanically compare the maximum pull-out strengths among two pedicle screws and three salvage techniques using poly methylmethacrylate (PMMA) augmentation in osteoporotic sacrum, and to determine which PMMA augmentation technique could serve as the salvage fixation for loosening sacral pedicle screws. Methods Eleven sacra were harvested from fresh adult donated cadavers, aged from 66 to 83 years (average 74.4 years) and included 5 men and 6 women. Radiography was used to exclude sacra that showed tumor or inflammatory or any other anatomic abnormal ities. Following the measurement of bone mineral density, five sacral screw fixations were sequentially establ ished on the same sacrum as follows: unicortical pedicle screw (group A), bicortical pedicle screw (group B), unicortical pedicle screw with the traditional PMMA augmentation (group C), ala screw with the traditional PMMA augmentation (group D), and ala screw with a kyphoplasty-assisted PMMA augmentation technique (group E). According to the sequence above, the axial pull-out test of each screw was conducted on a MTS-858 material testing machine. The maximum pull-out forces were measured and compared. The morphologies of PMMA augmented screws after being pulled-out were also inspected. Results The average bone mineral density of 11 osteoporotic specimens was (0.71 ± 0.08) g/cm2 . By observation of the pull-out screws, groups C, D, E showed perfect bonding with PMMA, and group E bonded more PMMA than groups C and D. The maximum pull-out forces of groups A, B, C, D, and E were (508 ± 128), (685 ± 126), (846 ± 230), (543 ± 121), and (702 ± 144) N, respectively. The maximum pull-out strength was significantly higher in groups B, C, and E than in groups A and D (P lt; 0.05), and in group C than in groups B and E (P lt; 0.05). There was no significant difference in pull-out strength between groups A and D, and between groups B and E (P gt; 0.05). Conclusion For sacral screw fixation of osteoporotic patients with bone mineral density more than 0.7 g/cm2, bicortical pedicle screw could acquire significantly higher fixation strength than the unicortical. Once the loosening of pedicle screw occurs, the traditional PMMA augmentation or ala screw with kyphoplasty-assisted PMMA augmentation may serve as a suitable salvage technique.
Objective To evaluate the effects of sacrectomy extent on the stabil ity of lumbo-il iac fixation using single or dual il iac screw technique, and to determine which conditions require the dual il iac screw technique. Methods Nine fresh L2 to pelvic specimens were harvested from donated adult cadavers. After testing the intact state simulated by L3-5 pedicle screw fixation, sequential partial sacrectomies and L3 to il iac fixation using bilateral single il iac screw (Single) wereconducted on the same specimen as follows: in group A, under S1 partial sacrectomy and Single; in group B, under 1/2 S1 partial sacrectomy and Single; in group C, one-side (left) sacroil iac joint resection and Single; in group D, total sacrectomy and Single; and in group E, the single il iac screw was replaced by dual il iac screws based on group D. Biomechanical testing was performed on a material testing machine under 0-800 N compression and —7-7 N?m torsion loading modes for construct stiffness evaluation. Results The compressive stiffness of intact condition was (392 ± 119) N/mm, groups A, B, C, D, and E obtained 106.4% ± 9.5%, 102.7% ± 8.0%, 92.2% ± 10.1%, 72.7% ± 8.0%, and 107.7% ± 10.7% of intact condition, respectively. No significant differences were found among groups A, B, C, and the intact state (P gt; 0.05), however, the four groups showed significantly higher compressive stiffness than group D (P lt; 0.05). Although group E exhibited a comparable compressive stiffness with groups A, B, and intact state (P gt; 0.05), it displayed markedly higher compressive stiffness than groups C and D (P lt; 0.05). The torsional stiffness of intact state was (3.22 ± 1.23) N?m/deg. Groups A, B, C, D, and E acquired 105.4% ± 10.1%, 89.8% ± 12.3%, 75.9% ± 10.6%, 71.2% ± 10.2%, and 109.1% ± 16.9% of intact state, respectively. No significant differences were detected among groups A, B, E, and the intact state (P gt; 0.05). However, groups C and D showed remarkably lower torsional stiffness than groups A, E, and the intact state (P lt; 0.05). Importantly, group E offered remarkably higher torsional stiffness than group B (P lt; 0.05). Conclusion After under 1/2 S1 partial sacrectomy, single il iac screw technique could effectively restore local stabil ity; whereas it could hardly provide adequate stabil ity for further resection of one-side sacroil iac joint or total sacrectomy; in such situation, the use of dual il iac screw technique could obtain sufficient construct stabil ity. Therefore, in the surgical treatment of sacral tumor, the dual il iac screw technique should be considered for the unstable conditions of totalsacrectomy or under 1/2 S1 sacrectomy with one-side sacroil iac joint resection.
ObjectiveTo explore the feasibility of the clinical application of individualized simulated S1 pedicle screw.MethodsThe data of patients with lumbar disease diagnosed and treated in the Fourth People’s Hospital of Zigong from May 2017 to April 2019 were retrospectively analyzed. According to the preoperative individualized design of the S1 pedicle screw placement path, the patients were divided into individualized screw placement group and traditional screw placement group. The distance D between the screw tip and the endplate of the S1, the angle α of the screw in the plane of the dysplasia and the lumbar pedicle of the L5, the angle of oblique angle β, the number of screws of 35 and 40 mm in length, and the screw loosening rate (followed-up within 1 year) in the two groups were analyzed.ResultsA total of 59 patients were enrolled in this study, 31 in the individualized screw placement group and 28 in the traditional screw placement group. The differences in the distance D between the screw tip and the endplate of the S1 [(2.61±0.82) vs.(4.13±1.51) mm; t=-5.718, P<0.001], the angle α of the screw in the plane of the dysplasia and the lumbar pedicle of the L5 [(9.31±3.52) vs. (13.53±4.78)°; t=-5.646, P<0.001], the angle of oblique angle β [(15.73±6.04) vs. (10.65±5.09)°; t=3.022, P=0.004], the proportion of using screw models [40 mm in length: 56 vs. 8; 35 mm in length: 6 vs. 48; χ2=68.539, P<0.001], and the screw loosening rate followed-up within 1 year [3.22% vs. 16.07%; χ2=5.774, P<0.001] were statistically significant between the individualized screw placement group and the traditional screw placement group.ConclusionsPreoperative individualized design of the pedicle screw of the S1 pedicle screw can be used in clinical practice. The biomechanical stability of the S1 pedicle screw can be improved and the sagittal balance can be achieved.
Objective To explore the method of the distal perforator-based gluteus maximus muscle V-Y flap to treat the sacral ulcer and to simplify the operative procedures.Methods From March 2002 to March 2005, 11 cases of sacral ulcer were repaired by distal perforatorbased gluteus maximus muscle flaps. The area of sacral ulcer ranged from 13 cm×11 cm to 18 cm×14 cm. Of 11 cases, 7 were female and 4 were male,whose age ranged from 21 to 69 years, and the disease course was 8 months to 3 years.A triangular flap was designed to create a V-Y advancement flap.The length of the base was made almost equal to the diameter of the defect.The apex of the tringle was located near the great trochanter. The medial part of the flap was elevated as a fasciocutaneous flap by dissecting the layer between the fascia and the muscle.The distal part ofthe flap was elevated by dissecting the layer between the gluteus maximus muscle and the fascia of the deeper muscle group.The flap was advanced to the defect. Results All the flaps survived. After a follow-up of 5 months to 3 years, the bilateral buttocks were symmetry and whose appearance was satisfactory. Except for 1 case dying of other disease, no recurrence of ulcer was observed.All the flaps survived. Conclusion The distal perforatorbased fasciocutaneous V-Y flap for treatment of sacral ulcers is a simple and reliable technique, which has several advantages over the conventional V-Y flap technique,such as excelent excursion,viable coverage with the fasciocutaneous component, high flap reliability, preservation of the contralateral buttock, and preservation of the gluteus maximus muscle function.
OBJECTIVE: To investigate an alternative procedure for complete denervation of bladder in the supra-cone cord injury to restore the bladder function. METHODS: Sixteen dogs were included in this study after their spinal cords were transected above the cone. They were divided into 6 groups and performed the rhizotomy of L7 to S3 root in different combination respectively. The bladder and urethra pressure change by electrostimulation during operation and cystometrogram change after operation were tested. RESULTS: 1. Electrostimulation study: for bladder innervation, S2was the most important and S1 was secondary. While for urethra innervation, S1 was more important than S2. When the anterior and posterior roots of S1 and S2 were intact with rhizotomy of posterior roots of L7 and S3, stimulated the common or posterior root of S1 and S2, the change of pressure in bladder and urethra was the same. When the anterior roots of S1 and S2 were resected with rhizotomy of posterior roots of L7 and S3, the pressure in bladder and urethra was significant decreased compared to stimulating the corresponding posterior roots. 2. Cystometrogram (CMG) study: in the complete deafferented group, resecting the posterior roots of L7 to S3, the bladder became flaccid. While resecting the posterior root of S2 and anterior root of S1 or, resecting the posterior root of S1 and anterior root of S2, combining with rhizotomy of posterior roots of L7 and S3, the CMG curve was similar to the complete deafferented group. In the S1 and S2 intact group, the bladder became spastic. CONCLUSION: Combining rhizotomy of anterior and posterior sacral root in different level has the same effects on bladder as complete deafferentation.
Objective To evaluate the effectiveness of lumbopelvic fixation using the combination of closed multi-axial screws (CMAS) iliosacral fixation system and the posterior segmental spinal fixation for unstable sacral fractures. Methods Between January 2013 and November 2014, 25 patients (39 sides) with unstable sacral fractures were treated with lumbopelvic fixation using the combination of CMAS iliosacral fixation system and the posterior segmental spinal fixation. There were 17 males and 8 females, aged 19-55 years (mean, 33.9 years). The causes were traffic accident injury in 15 cases, falling injury from height in 8 cases, and crushing injury in 2 cases. The interval of injury and operation was 1-13 days (mean, 3.5 days). Fracture was classified as Denis type I in 2 sides, type II in 20 sides, and type III in 17 sides; nerve injury was rated as Gibbons grade I in 2 cases, grade II in 2 cases, grade III in 7 cases, and grade IV in 9 cases. The reduction quality was evaluated by Matta criterion, the clinical function outcome by Majeed, and nerve function by Gibbons criterion. Results The average operation time was 110 minutes (range, 80-150 minutes). The average blood loss was 570 mL (range, 250-1 400 mL). Superficial wound infection occurred in 2 patients, and was cured after debridement and antibiotic therapy. All patients were followed up for an average of 18 months (range, 15-22 months). Postoperative X-ray and CT examination showed clinical healing of sacral fractures at 8-12 weeks after operation (mean, 10 weeks). The mean removal time of internal fixation was 13 months (range, 12-20 months). No screw loosening and fracture, adhesion of internal fixation to surrounding tissue, and obvious electrolysis phenomenon occurred. According to Matta criterion, reduction was rated as excellent in 32 sides, good in 6 sides, fair in 1 side, and the excellent and good rate was 97.5%. According to Majeed functional scoring at last follow-up, the mean score was 84.7 (range, 64-98); the results were excellent in 18 cases, good in 5 cases, and fair in 2 cases, and the excellent and good rate was 92.0%. The nerve function was significantly improved when compared with preoperative one; nerve injury was rated as Gibbons grade I in 8 cases, grade II in 8 cases, grade III in 3 cases, and grade IV in 1 case. Conclusion Lumbopelvic fixation using the combination of CMAS iliosacral fixation system and the posterior segmental spinal fixation is a relatively effective fixation for unstable sacral fractures. Not only is the fracture fixation rigid for early full weight-bearing, but also nerve decompression can be performed which facilitates nerve function recovery.
Objective To evaluate the effectiveness and safety of sacral neuromodulation (SNM) in the treatment of neurogenic bladder and bowel dysfunction in patients with spina bifida. Methods The clinical data of 33 patients with neurogenic bladder and bowel dysfunction caused by spina bifida treated with SNM between July 2012 and May 2021 were retrospectively analyzed. There were 19 males and 14 females, with an average age of 26.0 years (range, 18.5-36.5 years). The disease duration ranged from 12 to 456 months, with an average of 195.8 months. The types of spina bifida included 8 cases of occult spina bifida and 25 cases of meningocele/myelomeningocele. Clinical symptoms included 19 cases of urgency-frequent urination, 18 cases of urinary incontinence, 27 cases of chronic urinary retention, and 29 cases of bowel dysfunction. Image urodynamics showed that 4 patients had detrusor overactivity (DO) and 29 patients had detrusor underactivity (DU). Vesicoureteral reflux (VUR) was found in 5 ureters (4 patients). SNM procedure was divided into experiential treatment and permanent implantation. Patients who were evaluated as successful or willing to be permanently implanted after experiential treatment would implant the permanent pulse generator. ResultsThe duration of experiential treatment was 14-28 days, with an average of 19.2 days; there was no complication during this period, and the overall success rate was 69.69% (23/33). At the end of experiential treatment, the urination frequency in 24 hours, urine volume per time, urinary urgency score, and urine leakage of patients were significantly improved when compared with those before experiential treatment (P<0.05); there was no significant difference in postvoid residual volume between before and after experiential treatment (t=1.383, P=0.179). The success rate of patients with chronic urinary retention after experiential treatment (25.93%) was significantly lower than that of urgency-frequent urination (63.16%) and urinary incontinence (61.11%) (χ2=7.260, P=0.064). Compared with those before experiential treatment, the maximum cystometric capacity and compliance increased and the maximum detrusor pressure during filling decreased significantly (P<0.05). Among the 4 patients with DO before experiential treatment, DO disappeared in 2 cases; 27 patients with DU before experiential treatment did not recover the normal contraction of detrusor during micturition. Among the 5 ureters with VUR before experiential treatment, 2 VUR disappeared at the end of experiential treatment, and the VUR grade or the bladder volume before VUR of the other 3 ureters were improved. At the end of experiential treatment, the neurogenic bowel dysfunction (NBD) score and the grade of bowel dysfunction significantly improved (P<0.05). A total of 19 patients received permanent implantation, of which 11 patients needed to empty the bladder in combination with intermittent catheterization. ConclusionSNM is effective for neurogenic bladder and bowel dysfunction in patients with spina bifida. At the same time, it can significantly improve the urodynamic parameters during urine storage and avoid upper urinary tract damage.
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.
Objective To study the MRI diagnosis of sacral fracture with sacral neurological damage and its cl inical appl ication. Methods From October 1999 to October 2007, 20 cases of sacral fracture (Denis classification, Type II)with sacral neurological damage were examined by obl ique coronal MRI of sacrum to show the whole length of sacral nerve. There were 17 males and 3 females, aged 30-55 years. The time from injury to hospital ization varied from 1 day to 23 months. The injury was caused by traffic accident in 10 cases, smash of heavy object in 8 cases and crush in 2 cases. Eight cases were accompanied by pubis fracture and 4 cases by urethral disruption. All patients accepted the examination of X-ray, CT and spiral CT 3D reconstruction. X-ray showed the displacement of fracture fragment was backwards and upwards, and sacral-hole l ine was vague, asymmetric and distorted. CT showed that sacral neural tube was left-right asymmetry, the displacement of fracture fragment was backwards and upwards, combining with the compression and intruding to sacrum center at different section levels. The cl inical manifestations, international standards for Neurological Classification of Spinal Cord Injury recommended by American Spinal Injury Association International Spinal Cord Society, comparison between normal and abnormal MRI and Gierada’s results were the basis for cl inical diagnose and MRI diagnose, which was confirmed by operation. Results Nerve injury diagnosed by cl inical manifestation were S1 (17 cases), S2 (14 cases), S3 (7 cases), and S4 (6 cases). Nerve injury diagnosedby MRI were S1 (17 cases), S2 (14 cases), S3 (3 cases), and S4 (2 cases). Nerve injury confirmed by operation were S1 (17 cases), S2 (14 cases), S3 (7 cases), and S4 (1 case). Obl ique coronal MRI of sacrum showed the whole length of sacral nerve and its adjacent relationship, detecting bone fragment compression and route alteration of never were evident in 5 cases, the fat disappearance around the site of nerve root injury in 19 cases, narrowness of sacral nerve canal in 17 cases and the abnormally enlarged sacral nerve in 11 cases. Conclusion Obl ique coronal MRI of sacrum is of great value in the local ization and the qual itative diagnosis of sacral neurological damage.