The authors report a case of lumbar para-spinal muscle herniation following percutaneous thoraco-lumbar pedicle screw fixation. This is suggested to be due to subclinical iatrogenic increase in the intra-compartmental pressure. The possibility of ‘Iatrogenic paraspinal compartment syndrome’ following minimally invasive spine techniques has been discussed previously by other authors. Nevertheless, no such case has been reported so far in the literature. The awareness of this potential complication might be helpful for spinal surgeons for early detection and management.

A rare case of tumoural calcinosis of the cervical spine is presented. Tumoural calcinosis presents with masses of dystrophic calcification in juxta-articular areas. It is very rare in the cervical spine with few cases described in the literature so far. It remains part of the differential diagnosis for any calcified spinal compressive lesion.

OBJECT The authors prospectively evaluated the clinical and radiological outcomes after anterior cervical discectomy and fusion (ACDF) involving placement of a Solis cage and local autograft in patients who presented with symptomatic cervical spondylosis. METHODS Twenty-two consecutive patients underwent ACDF for radiculopathy (13 cases), myeloradiculopathy (eight cases), or myelopathy alone (one case) and were assessed at 3, 6, and 12 months. Plain cervical spine radiography demonstrated a significant change in both local (p < 0.05) and regional (p < 0.05) kyphotic angles as well as an increase in segmental height (p < 0.05). At 12 months, plain radiography demonstrated Grades I, II, and III new bone formation in two, three, and 17 patients, respectively. Clinical outcomes were assessed using a visual analog scale for both neck and arm pain and a modified Japanese Orthopaedic Association (JOA) scale for myelopathy. There was a significant improvement in both arm (p < 0.05) and neck pain (p < 0.05). At 12 months, 16 (84%) of 19 and 19 (86%) of 22 patients reported complete resolution of arm pain and neck pain, respectively. There was a significant improvement in JOA scores following surgery (p < 0.05). There were two complications in the series: one case of deep venous thrombosis and one case of postoperative arm pain that resolved after conservative treatment. There were no technical complications. CONCLUSIONS Early experience with Solis cage-augmented ACDF indicates good clinical and radiological outcomes; additionally, there are the advantages of absent donor site morbidity and anterior plate system-related morbidity.

BACKGROUND:Brain stem lesions are a heterogenous pathological group. In adults, pre-operative radiological diagnoses prove to be wrong in 10 to 20% of cases. It is therefore imperative to have a tissue diagnosis for appropriate therapeutic measures. Unless these lesions have a sizeable exophytic component, open biopsy and/or resection is marred by low diagnostic yield and prohibitive mortality/morbidity rates.METHODS:We describe our experience with awake stereotactic biopsy of brain stem lesions. Keeping the patient awake and monitoring clinically during the procedure allows us to make necessary changes in the trajectory of the biopsy probe to minimize the morbidity. A series of 13 brain stem lesions were stereotactically biopsied using CT guidance. Seven had midbrain lesions; four had pontine and two had Ponto-medullary lesions. A frontal, pre-coronal, transcortical trajectory was used in all patients.FINDINGS:Histological diagnosis was established in all but one patient. There was no procedural mortality, and morbidity was minimal and temporary, occurring in three patients.CONCLUSION:Awake stereotactic biopsy is a safe technique when combined with clinical monitoring.

The objective of this study is to determine the usefulness of single-patient, randomised, controlled trials (N-of-1 trials) in assessing the efficacy of deep brain stimulation (DBS) in neuropathic pain. Seven patients with various causes of intractable neuropathic pain underwent insertion of deep brain stimulating electrodes into the periventricular gray area or ventroposterolateral nucleus of the thalamus. Preoperatively, pain was measured using Visual Analog Scales (VAS) and the McGill Pain Questionnaire (MPQ). At 6 months, these pain assessments were repeated. At this point all patients were entered into a N-of-1 trial with the DBS on and off. Data were analyzed using the Wilcoxon and Student t-tests. Following placement of the deep brain stimulator, VAS scores were significantly reduced in six of seven patients. McGill Pain Scores (MPS) showed pain reduction in four of seven. The results of the N-of-1 trials were most similar to the MPQ scores and showed that three of seven patients could accurately predict whether the DBS was on or off. In the N-of-1 trials, the time between changing the DBS from on to off (or vice versa) had an effect on the results and probably underestimated the efficacy. We conclude that N-of-1 trials are a useful tool for assessing DBS efficacy.

Deep brain stimulation (DBS) therapy is a continually expanding field in the functional neurosurgical treatment of movement disorders. However, the occurrence of adverse events related to implanted hardware cannot be overlooked. We report on a specific feature noted in our experience of DBS-related complications. From 1998 until present we have found an overall rate of 5.3% of DBS electrode lead dysfunction (out of 133 patients) in our series (slipped leads 2.3%, lead fracture 3.8%). Interestingly, all of these failures occurred in dystonia patients (18.4% of all dystonia patients and 9.2% of all electrodes). We postulate on mechanisms that may explain why these complications predominate in this group of patients.

Objective To assess the usefulness, compatibility, and long-term operability of a microelectrode array into the median nerve of the left arm of a healthy volunteer, including perception of feedback stimulation and operation of an instrumented prosthetic hand. Setting The study was carried out from March 14 through June 18, 2002, in England and the United States. Results The blindfolded subject received feedback information, obtained from force and slip sensors on the prosthetic hand, and subsequently used the implanted device to control the hand by applying an appropriate force to grip an unseen object. Operability was also demonstrated remotely via the Internet, with the subject in New York, NY, and the prosthetic hand in Reading, England. Finally, the subject was able to control an electric wheelchair, via decoded signals from the implant device, to select the direction of travel by opening and closing his hand. The implantation did not result in infection or any perceivable loss of hand sensation or motion control. The implant was finally extracted because of mechanical fatigue of the percutaneous connection. Further testing after extraction has not indicated any measurable long-term defects in the subject. Conclusions This implant may allow recipients to have abilities they would otherwise not possess. The response to stimulation improved considerably during the trial, suggesting that the subject learned to process the incoming information more effectively.

Background. We describe the management of osteomyelitis of the cervical spine, utilizing internal fixation with subsequent removal and culture of the implants. Four out of five patients had evidence of bacterial colonisation in close proximity to the internal fixation device.Methods. Five consecutive patients (all female, ranging in age from 50 to 74 yrs) presenting with unstable cervical osteomyelitis were treated by surgical decompression, primary internal fixation followed by three months of intravenous antibiotics. The internal fixation was removed in 4 out of 5 cases within a year of stopping the intravenous regime. The remaining patient was deemed medically unfit for further operation. Multiple specimens from the screw sites were taken at the time of metal removal. A final course of oral antibiotics was prescribed based on the results of these specimens.Findings. Four patients, who had removal of the implants, had positive cultures growing different bacteria from the primary infection, at the time of removal of the implant. None of the patients developed instability after removal of the implant.Interpretation. Asymptomatic bacterial colonisation of a metallic implant has profound management implications. We recommend long-term oral antibiotic regimes after insertion of internal fixation devices in the face of infection and eventual removal of these implants and microbiological re-sampling.

The majority of rheumatoid arthritis patients with C1/2 instability causing neck pain and neurological compromise can be treated with unisegmental fusion. However, a minority will require decompression and more extensive craniocervical fusion. Two cohorts of patients with rheumatoid arthritis requiring decompression and craniocervical fusion were included in a retrospective study comparing sublaminar wiring (Ransford Loop, n = 10, follow-up = 36 +/- 9.5 months) and lateral mass screws (Cervifix system, n = 11; follow-up = 39.7 +/- 7.9 months). Both cohorts of patients experienced significant improvements in high cervical pain scores [McGill 5-point score; preop = 4.5 +/- 0.75 for Cervifix and 4.5 +/- 0.75 for Ransford loop; postop = 1.17 +/- 0.9 (p = 0.003) for Cervifix (at 39.7 months +/-7.9) and 2.8 +/- 1.6 (p = 0.011) for Ransford loop (at 36 +/- 9.5 months)]. Lateral mass screws for craniocervical fusion (seven out of 11 pain free) appear to produce better early results for rheumatoid arthritis patients suffering high cervical neck pain than sublaminar wire techniques (three out of 10 pain free).

The strain-gauge Codman MicroSensor intracranial pressure (ICP) transducer has shown consistently good laboratory performance. To assess the practical performance of the system in patients following acute brain injury, 10 patients were fitted with a MicroSensor and a second ICP monitor. In five cases this was a fibre-optic transducer and in five cases an intraventricular fluid-filled device. Paired ICP values were recorded every 5 min. ICP values ranged from 0 to 31 mmHg. Altman-Bland plots showed that individual readings could differ by as much as 9 mmHg. Further analysis showed that much of this disagreement could be explained by a constant offset on each occasion. Comparison traces of ICP in individual patients show high agreement in timing and size of changes. The unexplained constant offset leads to uncertainty about the true ICP. Treatment decisions are often based upon absolute levels of ICP and patient care may therefore differ depending upon the monitor used.