Esa Kotilainen

Postoperative hematomas after successful lumbar microdiscectomy or percutaneous nucleotomy: a magnetic resonance imaging study.

We evaluated the incidence of postoperative extradural hematomas by means of magnetic resonance imaging (MRI) technique in 44 patients who underwent successful surgery for a virgin lumbar disc herniation. Of these patients, 28 were treated with microdiscectomy and 16 with percutaneous nucleotomy. Postoperative hematoma proved to be a universal MRI finding in the microsurgically treated patients: hematomas were found in all patients in the microdiscectomy group. In 12 (43%) patients the hematoma extended into the dural sack. The incidence of hematomas was significantly (p = 0.001) lower in the patients treated with percutaneous nucleotomy: hematomas were detected in only 10 (63%) of the 16 patients in the nucleotomy group. The hematomas in these patients were also smaller in size and none of them connected with the dural sac. Correlation between the hematomas and clinical findings showed that the presence of a hematoma had no obvious effect on the immediate postoperative recovery of a patient.

Histamine-containing nerve fibers innervate human cerebellum

Histamine is found in nerve cell bodies of the tuberomammillary nucleus in mammalian brain. This nucleus is prominent in human brain. Samples of human cerebelli obtained from neurosurgical operations were examined for the presence of histamine-containing nerve fibers. In all samples, a moderately dense network of histamine-immunoreactive fibers was seen in the molecular layer. These fibers ran parallel to the Purkinje cell layer after traversing it perpendicularly. Numerous fibers were also seen in the granular cell layer. The results suggest that the human cerebellar cortex receives a direct input from histamine-synthesizing hypothalamic neurons, as no other histamine-containing neurons have been found in human brain.

Instrumented spondylodesis in degenerative spondylolisthesis with bioactive glass and autologous bone: a prospective 11-year follow-up.

A prospective long-term follow-up study of bioactive glass (BAG)-S53P4 and autogenous bone (AB) used as bone graft substitutes for posterolateral spondylodesis in treatment of degenerative spondylolisthesis during 1996 to 1998 was conducted. The surgical procedure was a standardized instrumented posterolateral fusion that used USS/VAS. BAG was implanted on the left side of the fusion bed and AB on the right side. The operative outcome was evaluated on x-rays and computed tomography scans, and a clinical examination was also performed. Seventeen patients (12 women, 5 men) participated in the 11-year follow-up. The mean Oswestry Disability Index score at the follow-up was 21 (range 0 to 52), compared with 49 (range 32 to 64) at the preoperative time. A solid bony fusion was seen on computed tomography scans on the AB side in all patients and on the BAG side in 12 patients. The fusion rate of all fusion sites (n=41) for BAG as a bone substitute was 88% at the L4/5 level and 88% at the L5/S1 level. The use of BAG as a bone graft extender can be considered as a good alternative in spinal surgery in the future.

Magnetic resonance image changes and clinical outcome after microdiscectomy or nucleotomy for ruptured disc

Preoperative and postoperative magnetic resonance imaging (MRI) of the lumbar spine was performed on 41 patients treated either microsurgically or with percutaneous nucleotomy for lumbar disc herniation. On the first postoperative day, MRI revealed an edematous mass effect at the level of surgery in 25 (61%) patients. The mass effect caused compression of the anterior dural sac mimicking preoperative disc herniation. After the follow-up of 6 months, the mass effect had disappeared in all patients, and the MRI finding in the operated disc space was that of a prolapse in six (15%) patients and that of a protrusion in 16 (39%) patients. Postoperative scarring was detected in 23 (56%) patients. The amount of the epidural scar tissue was significantly (p = 0.0002) associated with the extent of the early postoperative hemorrhagic changes detected in these patients with MRI. No association was observed between these MRI findings (mass effect, disc herniation, epidural scarring) and the clinical outcome of the patients.

Spontaneous epidural hematoma as a cause of sciatic pain in a schoolboy.

A previously healthy 13-year-old boy began to manifest radiating pain in his left leg after heavy physical exertion during judo training. He also had a sensation of numbness in his left buttock and leg. Initially, the patient was treated conservatively with a clinical diagnosis of disc herniation. However, following 3 months of conservative treatment, there was no relief of pain. Magnetic resonance imaging of the lumbar spine demonstrated an epidural mass causing compression of the dural sac at the L4-L5 disc level. During surgery, the L5 nerve root was found to be severely compressed in the spinal canal because of a chronic epidural hematoma. Following microsurgical removal of this hematoid mass, the patient had a good recovery. Spontaneous epidural hematomas in the lumbar region are rare, and only a few cases presenting with features simulating those caused by a disc herniation have been reported. Our patient represents the first such case described in a child.

Cross-sectional areas of lumbar muscles after surgical treatment of lumbar disc herniation: a study with magnetic resonance imaging after microdiscectomy or percutaneous nucleotomy

SummaryWe assessed in this study the potential development of postoperative muscle atrophy in the operation area in 39 patients treated by either microdiscectomy or percutaneous nucleotomy for lumbar disc herniation. The cross-sectional areas of the lumbar muscles were measured on magnetic resonance images created on the day preceding the operation and 6 months postoperatively. The cross-sections of the lumbar muscles remained unchanged during the observation period in all treated patients indicating that no muscle atrophy had developed in the operation area. Since peroperative tissue trauma may correlate with subsequent muscle denervation and atrophy, this finding may be due to the tissue sparing nature of microdiscectomy and percutaneous nucleotomy, thus encouraging the use of these techniques in the treatment of lumbar disc herniation.

In Vivo and In Vitro Study of a Polylactide-Fiber-Reinforced β-Tricalcium Phosphate Composite Cage in an Ovine Anterior Cervical Intercorporal Fusion Model

A poly-70L/30DL-lactide (PLA70)–β-tricalcium phosphate (β-TCP) composite implant reinforced by continuous PLA-96L/4D-lactide (PLA96) fibers was designed for in vivo spinal fusion. The pilot study was performed with four sheep, using titanium cage implants as controls. The composite implants failed to direct bone growth as desired, whereas the bone contact and the proper integration were evident with controls 6 months after implantation. Therefore, the PLA70/β-TCP composite matrix material was further analyzed in the in vitro experiment by human and ovine adipose stem cells (hASCs and oASCs). The composites proved to be biocompatible as confirmed by live/dead assay. The proliferation rate of oASCs was higher than that of hASCs at all times during the 28u2009d culture period. Furthermore, the composites had only a minor osteogenic effect on oASCs, whereas the hASC osteogenesis on PLA70/β-TCP composites was evident. In conclusion, the composite implant material can be applied with hASCs for tissue engineering but not be evaluated in vivo with sheep.

Spondylodesis in the treatment of segmental instability of the lumbar spine with special reference to clinically verified instability

SummaryWe analysed the outcome of 42 consecutive patients suffering from low back pain and segmental instability of the lumbar spine who underwent spondylodesis with transpedicular fixation. There were 29 (69%) females and 13 (31%) males with a mean age of 47±9 years (range 23 to 66 years). The presence of clinically verified instability was a basic requirement for operative treatment, with at least one clinical sign of instability positive in all patients. Radiological signs of instability were detected in only 74 % of the patients.After a postoperative follow-up of one year, lumbar fusion was found in 38 (90%) patients. The fusion was classified as complete in 18 (43%) and as partial in 20 (47%) patients. No fusion there was detected in 4 (10%) patients. Low back pain was completely abolished in 19 (45%) and markedly diminished in 15 (36 %) patients. In 7 (17%) patients, low back pain had remained unchanged and become worse in 1 (2%) patient. Clinical signs and symptoms of instability were still detected in 10 (24%) patients. As compared to the pre-operative situation, the decrease in clinical instability was statistically significant (p = 0.02). Moreover, a significant correlation was observed between the persistence of clinically verified instability and a poor postoperative outcome in daily activities. Of all patients, 17 (40%) returned to work during the period of followup. Based on the good outcome of our patients, the results of this study show that clinical signs and symptoms of instability can be successfully used as selection criteria for lumbar spondylodesis.

Accuracy of 837 pedicle screw positions in degenerative lumbar spine with conventional open surgery evaluated by computed tomography

BackgroundThe spatial and directional accuracy of the positioning of pedicle screws in the lumbosacral spine with conventional open surgery assessed by computed tomography (CT) has been published in several studies, systematic reviews and meta-analyses with a short-term follow-up. Inaccurate pedicle screw insertion may cause neurologic symptoms and weakens the construct.MethodsThe data of 147 patients operated on with transpedicular screw fixation based on anatomical landmarks, supported by fluoroscopy, by a senior neurosurgeon in our clinic between 2000 and 2010 were analyzed retrospectively. The accuracy of the pedicle screw position was assessed by using postoperative CT images and graded in 2-mm increments up to 6xa0mm by two independent surgeons and partly by an independent radiologist.ResultsA total of 837 lumbosacral pedicle screws were inserted in 147 randomly selected patients by a senior neurosurgeon. A mean accuracy of 85.7% of the screws being inside the pedicles was identified by the surgeon observers, with 3.3% being perforated 4xa0mm or more outside the pedicles. Postoperative neurologic symptoms were observed on the side corresponding to the breach in an average of 25.9% of patients with pedicle perforations, and 89.2% of the misplaced screws were either medially or inferiorly inserted.ConclusionsScrew application reached a mean accuracy of 85.7% based on anatomical landmarks supported by fluoroscopy, warranting computer-assisted navigation for increased accuracy. Our results of 24 patients (16.3%) with the breached screws indicate that the direction of the breach may be more important than the absolute deviation in causing new neurologic symptoms.

A microsurgical technique for posterior lumbar interbody fusion: technical note.

Summaryu2003Objective. To describe a microsurgical modification of the Ray Threaded Fusion Cage (TFC) instrumentation technique for achieving lumbar interbody fusion.u2003Technique. The lumbar fusion is established by application of two titanium cages through two different short skin incisions, first on one and then on the other side. The spinous processes and the whole interspinous ligament are preserved. Under microscopic control, the lower nerve root and foramen are identified and foraminotomy performed. The dural sac is carefully exposed so that a free and gentle retraction of the nerve root to the midline can be obtained. After removal of the disc material, the retractor is inserted. Special attention should be paid to visualization of the superior nerve root in order to avoid neural injuries. The end plate and disc material are then drilled and tapped for insertion of the appropriate cage.u2003Conclusion. The Ray TFC lumbar fusion can be practically and safely performed under microscopic control.