To report the development of the technique for minimally invasive lumbar decompression using robotic-assisted navigation. Robotic planning software was used to map out bone removal for a laminar decompression after registration of CT scan images of one cadaveric specimen. A specialized acorn-shaped bone removal robotic drill was used to complete a robotic lumbar laminectomy. Post-procedure advanced imaging was obtained to compare actual bony decompression to the surgical plan. After confirming accuracy of the technique, a minimally invasive robotic-assisted laminectomy was performed on one 72-year-old female patient with lumbar spinal stenosis. Postoperative advanced imaging was obtained to confirm the decompression.Aims
Methods
The aim of this study was to investigate the incidence and characteristics of instrumentation failure (IF) after total en bloc spondylectomy (TES), and to analyze risk factors for IF. The medical records from 136 patients (65 male, 71 female) with a mean age of 52.7 years (14 to 80) who underwent TES were retrospectively reviewed. The mean follow-up period was 101 months (36 to 232). Analyzed factors included incidence of IF, age, sex, BMI, history of chemotherapy or radiotherapy, tumour histology (primary or metastasis; benign or malignant), surgical approach (posterior or combined), tumour location (thoracic or lumbar; junctional or non-junctional), number of resected vertebrae (single or multilevel), anterior resection line (disc-to-disc or intravertebra), type of bone graft (autograft or frozen autograft), cage subsidence (CS), and local alignment (LA). A survival analysis of the instrumentation was performed, and relationships between IF and other factors were investigated using the Cox regression model.Aims
Methods
Anchorage of pedicle screw rod instrumentation in the elderly spine with poor bone quality remains challenging. Our study aims to evaluate how the screw bone anchorage is affected by screw design, bone quality, loading conditions, and cementing techniques. Micro-finite element (µFE) models were created from micro-CT (μCT) scans of vertebrae implanted with two types of pedicle screws (L: Ennovate and R: S4). Simulations were conducted for a 10 mm radius region of interest (ROI) around each screw and for a full vertebra (FV) where different cementing scenarios were simulated around the screw tips. Stiffness was calculated in pull-out and anterior bending loads.Aims
Methods
High-grade dysplastic spondylolisthesis is a disabling disorder for which many different operative techniques have been described. The aim of this study is to evaluate Scoliosis Research Society 22-item (SRS-22r) scores, global balance, and regional spino-pelvic alignment from two to 25 years after surgery for high-grade dysplastic spondylolisthesis using an all-posterior partial reduction, transfixation technique. SRS-22r and full-spine lateral radiographs were collected for the 28 young patients (age 13.4 years (SD 2.6) who underwent surgery for high-grade dysplastic spondylolisthesis in our centre (Scottish National Spinal Deformity Service) between 1995 and 2018. The mean follow-up was nine years (2 to 25), and one patient was lost to follow-up. The standard surgical technique was an all-posterior, partial reduction, and S1 to L5 transfixation screw technique without direct decompression. Parameters for segmental (slip percentage, Dubousset’s lumbosacral angle) and regional alignment (pelvic tilt, sacral slope, L5 incidence, lumbar lordosis, and thoracic kyphosis) and global balance (T1 spino-pelvic inclination) were measured. SRS-22r scores were compared between patients with a balanced and unbalanced pelvis at final follow-up.Aims
Methods
The purpose of this retrospective study was to investigate the
clinical relevance of increased facet joint distraction as a result
of anterior cervical decompression and fusion (ACDF) for trauma. A total of 155 patients (130 men, 25 women. Mean age 42.7 years;
16 to 87) who had undergone ACDF between 1 January 2001 and 1 January
2016 were included in the study. Outcome measures included the Neck
Disability Index (NDI) and visual analogue scale (VAS) for pain.
Lateral cervical spine radiographs taken in the immediate postoperative
period were reviewed to compare the interfacet distance of the operated
segment with those of the facet joints above and below.Aims
Patients and Methods
The aim of this study is to introduce and investigate the efficacy
and feasibility of a new vertebral osteotomy technique, vertebral
column decancellation (VCD), for rigid thoracolumbar kyphotic deformity
(TLKD) secondary to ankylosing spondylitis (AS). We took 39 patients from between January 2009 and January 2013
(26 male, 13 female, mean age 37.4 years, 28 to 54) with AS and
a TLKD who underwent VCD (VCD group) and compared their outcome
with 45 patients (31 male, 14 female, mean age 34.8 years, 23 to
47) with AS and TLKD, who underwent pedicle subtraction osteotomy
(PSO group), according to the same selection criteria. The technique
of VCD was performed at single vertebral level in the thoracolumbar
region of AS patients according to classification of AS kyphotic
deformity. Pre- and post-operative chin-brow vertical angle (CBVA),
sagittal vertical axis (SVA) and sagittal Cobb angle in the thoracolumbar
region were reviewed in the VCD and PSO groups. Intra- , post-operative
and general complications were analysed in both group.Aims
Patients and Methods
We performed a systematic review of the literature to determine the safety and efficacy of bone morphogenetic protein (BMP) compared with bone graft when used specifically for revision spinal fusion surgery secondary to pseudarthrosis. The MEDLINE, EMBASE and Cochrane Library databases were searched using defined search terms. The primary outcome measure was spinal fusion, assessed as success or failure in accordance with radiograph, MRI or CT scan review at 24-month follow-up. The secondary outcome measure was time to fusion.Objectives
Methods
In a multicentre, randomised study of adolescents undergoing
posterior spinal fusion for idiopathic scoliosis, we investigated
the effect of adding gelatine matrix with human thrombin to the
standard surgical methods of controlling blood loss. Patients in the intervention group (n = 30) were randomised to
receive a minimum of two and a maximum of four units of gelatine
matrix with thrombin in addition to conventional surgical methods
of achieving haemostasis. Only conventional surgical methods were
used in the control group (n = 30). We measured the intra-operative
and total blood loss (intra-operative blood loss plus post-operative
drain output).Aims
Patients and Methods
To employ a simple and fast method to evaluate those patients with neurological deficits and misplaced screws in relatively safe lumbosacral spine, and to determine if it is necessary to undertake revision surgery. A total of 316 patients were treated by fixation of lumbar and lumbosacral transpedicle screws at our institution from January 2011 to December 2012. We designed the criteria for post-operative revision scores of pedicle screw malpositioning (PRSPSM) in the lumbosacral canal. We recommend the revision of the misplaced pedicle screw in patients with PRSPSM = 5′ as early as possible. However, patients with PRSPSM < 5′ need to follow the next consecutive assessment procedures. A total of 15 patients were included according to at least three-stage follow-up.Objectives
Methods
We reviewed 34 consecutive patients (18 female-16 male) with
isthmic spondylolysis and grade I to II lumbosacral spondylolisthesis
who underwent in situ posterolateral arthodesis between the L5 transverse
processes and the sacral ala with the use of iliac crest autograft.
Ten patients had an associated scoliosis which required surgical correction
at a later stage only in two patients with idiopathic curves unrelated
to the spondylolisthesis. No patient underwent spinal decompression or instrumentation
placement. Mean surgical time was 1.5 hours (1 to 1.8) and intra-operative
blood loss 200 ml (150 to 340). There was one wound infection treated
with antibiotics but no other complication. Radiological assessment
included standing posteroanterior and lateral, Ferguson and lateral flexion/extension
views, as well as CT scans. Aims
Methods
Percutaneous placement of pedicle screws is a
well-established technique, however, no studies have compared percutaneous
and open placement of screws in the thoracic spine. The aim of this
cadaveric study was to compare the accuracy and safety of these
techniques at the thoracic spinal level. A total of 288 screws were
inserted in 16 (eight cadavers, 144 screws in percutaneous and eight
cadavers, 144 screws in open). Pedicle perforations and fractures
were documented subsequent to wide laminectomy followed by skeletalisation
of the vertebrae. The perforations were classified as grade 0: no
perforation, grade 1: <
2 mm perforation, grade 2: 2 mm to 4
mm perforation and grade 3: >
4 mm perforation. In the percutaneous
group, the perforation rate was 11.1% with 15 (10.4%) grade 1 and
one (0.7%) grade 2 perforations. In the open group, the perforation
rate was 8.3% (12 screws) and all were grade 1. This difference
was not significant (p = 0.45). There were 19 (13.2%) pedicle fractures
in the percutaneous group and 21 (14.6%) in the open group (p =
0.73). In summary, the safety of percutaneous fluoroscopy-guided
pedicle screw placement in the thoracic spine between T4 and T12
is similar to that of the conventional open technique. Cite this article:
Transarticular screw fixation with autograft
is an established procedure for the surgical treatment of atlantoaxial instability.
Removal of the posterior arch of C1 may affect the rate of fusion.
This study assessed the rate of atlantoaxial fusion using transarticular
screws with or without removal of the posterior arch of C1. We reviewed
30 consecutive patients who underwent atlantoaxial fusion with a
minimum follow-up of two years. In 25 patients (group A) the posterior
arch of C1 was not excised (group A) and in five it was (group B).
Fusion was assessed on static and dynamic radiographs. In selected
patients CT imaging was also used to assess fusion and the position
of the screws. There were 15 men and 15 women with a mean age of
51.2 years (23 to 77) and a mean follow-up of 7.7 years (2 to 11.6).
Stable union with a solid fusion or a stable fibrous union was achieved
in 29 patients (97%). In Group A, 20 patients (80%) achieved a solid
fusion, four (16%) a stable fibrous union and one (4%) a nonunion.
In Group B, stable union was achieved in all patients, three having
a solid fusion and two a stable fibrous union. There was no statistically
significant difference between the status of fusion in the two groups.
Complications were noted in 12 patients (40%); these were mainly
related to the screws, and included malpositioning and breakage.
The presence of an intact or removed posterior arch of C1 did not
affect the rate of fusion in patients with atlantoaxial instability
undergoing C1/C2 fusion using transarticular screws and autograft. Cite this article:
We compared the clinical, radiological and quality-of-life
outcomes between hybrid and total pedicle screw instrumentation
in patients undergoing surgery for neuromuscular scoliosis. Total pedicle screw instrumentation provided shorter operating
times, less blood loss and better correction of the major curve
compared with hybrid constructs in patients undergoing surgery for
neuromuscular scoliosis.
We describe the results of a prospective case series of patients with spondylolysis, evaluating a technique of direct stabilisation of the pars interarticularis with a construct that consists of a pair of pedicle screws connected by a U-shaped modular link passing beneath the spinous process. Tightening the link to the screws compresses bone graft in the defect in the pars, providing rigid intrasegmental fixation. We have carried out this procedure on 20 patients aged between nine and 21 years with a defect of the pars at L5, confirmed on CT. The mean age of the patients was 13.9 years (9 to 21). They had a grade I or less spondylolisthesis and no evidence of intervertebral degeneration on MRI. The mean follow-up was four years (2.3 to 7.3). The patients were assessed by the Oswestry Disability Index (ODI) and a visual analogue scale (VAS). At the latest follow-up, 18 patients had an excellent clinical outcome, with a significant (p <
0.001) improvement in their ODI and VAS scores. The mean ODI score at final follow-up was 8%. Assessment of the defect by CT showed a rate of union of 80%. There were no complications involving the internal fixation. The strength of the construct removes the need for post-operative immobilisation.
We evaluated the efficacy of anterior fusion alone compared with combined anterior and posterior fusion for the treatment of degenerative cervical kyphosis. Anterior fusion alone was undertaken in 15 patients (group A) and combined anterior and posterior fusion was carried out in a further 15 (group B). The degree and maintenance of the angle of correction, the incidence of graft subsidence, degeneration at adjacent levels and the rate of fusion were assessed radiologically and clinically and the rate of complications recorded. The mean angle of correction in group B was significantly higher than in group A (p = 0.0009). The mean visual analogue scale and the neck disability index in group B was better than in group A (p = 0.043, 0.0006). The mean operation time and the blood loss in B were greater than in group A (p <
0.0001, 0.037). Pseudarthrosis, subsidence of the cage, and problems related to the hardware were more prevalent in group A than in group B (p = 0.034, 0.025, 0.013). Although the combined procedure resulted in a longer operating time and greater blood loss than with anterior fusion alone, our results suggest that for the treatment of degenerative cervical kyphosis the combined approach leads to better maintenance of sagittal alignment, a higher rate of fusion, a lower incidence of complications and a better clinical outcome.
Lumbar spondylolysis is a stress fracture of the pars interarticularis. We have evaluated the site of origin of the fracture clinically and biomechanically. Ten adolescents with incomplete stress fractures of the pars (four bilateral) were included in our study. There were seven boys and three girls aged between 11 and 17 years. The site of the fracture was confirmed by axial and sagittal reconstructed CT. The maximum principal tensile stresses and their locations in the L5 pars during lumbar movement were calculated using a three-dimensional finite-element model of the L3-S1 segment. In all ten patients the fracture line was seen only at the caudal-ventral aspect of the pars and did not spread completely to the craniodorsal aspect. According to the finite-element analysis, the higher stresses were found at the caudal-ventral aspect in all loading modes. In extension, the stress was twofold higher in the ventral than in the dorsal aspect. Our radiological and biomechanical results were in agreement with our clinical observations.
We reviewed the outcome of a retrospective case series of eight patients with atlantoaxial instability who had been treated by percutaneous anterior transarticular screw fixation and grafting under image-intensifier guidance between December 2005 and June 2008. The mean follow-up was 19 months (8 to 27). All eight patients had a solid C1–2 fusion. There were no breakages or displacement of screws. All the patients with pre-operative neck pain had immediate relief from their symptoms or considerable improvement. There were no major complications. Our preliminary clinical results suggest that percutaneous anterior transarticulation screw fixation is technically feasible, safe, useful and minimally invasive when using the appropriate instruments allied to intra-operative image intensification, and by selecting the correct puncture point, angle and depth of insertion.
It has been noted that bony union of a pars defect can be achieved in children if they wear a trunk brace. Our aim was to evaluate how the stage of the defect on CT and the presence or absence of high signal change in the adjacent pedicle on T2-weighted MRI were related to bony healing. We treated 23 children conservatively for at least three months. There were 19 boys and four girls with a mean age of 13.5 years (7 to 17). They were asked to refrain from sporting activity and to wear a Damen soft thoracolumbosacral type brace. There were 41 pars defects in 23 patients. These were classified as an early, progressive or terminal stage on CT. The early-stage lesions had a hairline crack in the pars interarticularis, which became a gap in the progressive stage. A terminal-stage defect was equivalent to a pseudarthrosis. On the T2-weighted MR scan the presence or absence of high signal change in the adjacent pedicle was assessed and on this basis the defects were divided into high signal change-positive or -negative. Healing of the defect was assessed by CT. In all, 13 (87%) of the 15 early defects healed. Of 19 progressive defects, only six (32%) healed. None of the seven terminal defects healed. Of the 26 high signal change-positive defects 20 (77%) healed after conservative treatment whereas none of the high signal change-negative defects did so. We concluded that an early-stage defect on CT and high signal change in the adjacent pedicle on a T2-weighted MR scan are useful predictors of bony healing of a pars defect in children after conservative treatment.
Anterior debridement, grafting of the defect and posterior instrumentation as a single-stage procedure is a controversial method of managing pyogenic vertebral osteomyelitis. Between 1994 and 2005, 37 patients underwent this procedure at our hospital, of which two died and three had inadequate follow-up. The remaining 32 were reviewed for a mean of 36 months (12 to 66). Their mean age was 48 years (17 to 68). A significant pre-operative neurological deficit was present in 13 patients (41%). The mean duration of surgery was 285 minutes (240 to 360) and the mean blood loss was 900 ml (300 to 1600). Pyogenic organisms were isolated in 21 patients (66%). All patients began to mobilise on the second post-operative day. The mean hospital stay was 13.6 days (10 to 20). Appropriate antibiotics were administered for 10 to 12 weeks. Early wound infection occurred in four patients (12.5%), and late infection in two (6.3%). At final follow-up, the infection had resolved in all patients, neurological recovery was seen in ten of 13 (76.9%) and interbody fusion had occurred in 30 (94%). The clinical outcome was excellent or good in 30 patients according to Macnab’s criteria. This surgical protocol can be used to good effect in patients with pyogenic vertebral osteomyelitis when combined with appropriate antibiotic therapy.
There are few reports of the treatment of lumbar tuberculous spondylitis using the posterior approach. Between January 1999 and February 2004, 16 patients underwent posterior lumbar interbody fusion with autogenous iliac-bone grafting and pedicle screw instrumentation. Their mean age at surgery was 51 years (28 to 66). The mean follow-up period was 33 months (24 to 48). The clinical outcome was assessed using the Frankel neurological classification and the Kirkaldy-Willis criteria. On the Frankel classification, one patient improved by two grades (C to E), seven by one grade, and eight showed no change. The Kirkaldy-Willis functional outcome was classified as excellent in eight patients, good in five, fair in two and poor in one. Bony union was achieved within one year in 15 patients. The mean pre-operative lordotic angle was 27.8° (9° to 45°) which improved by the final follow-up to 35.8° (28° to 48°). Post-operative complications occurred in four patients, transient root injury in two, a superficial wound infection in one and a deep wound infection in one, in whom the implant was removed. Our results show that a posterior lumbar interbody fusion with autogenous iliac-bone grafting and pedicle screw instrumentation for tuberculous spondylitis through the posterior approach can give satisfactory results.
