Spine

Shared decision-making in scoliosis surgery X-ref

Shared decision-making is a wholly unorthopaedic approach in many healthcare institutions. However, it is crucially important in everything from patient satisfaction through to medicolegal defensiveness. There are few more complex settings in which to attempt to achieve this than in spinal neuromuscular scoliosis surgery. The combination of complex decision-making, involvement usually of caregivers and a complicated risk benefit balance can make achieving a satisfactory decision rather difficult. Using a novel approach, spinal surgeons in Jacksonville (USA) report their efforts to apply a decision-making aid to this process.¹ Their study reports the development of a decision aid using a multistep process of expert summation of current evidence, involvement of a multidisciplinary group and assessment against agreed decision aid standards. The aid was then utilised in a prospective fashion on 11 children, nine of whom opted for surgery following the process. The authors were able to report improvements in knowledge gain, satisfaction and decisional conflict by the caregivers in this particular setting. They conclude that the aid itself is a success and encourage the development of additional decision aids for other similar diagnoses.

Diabetes and outcomes in spinal surgery

Diabetes is associated with almost every complication imaginable, and diabetics come to accept that the nature of their metabolic disorder is such that complications are associated with simple surgery, and almost every organ is affected. Whilst there has been a reasonable focus on the effects of diabetes in terms of outcomes, there is little in the way of longer-term research establishing the effect (or otherwise) on surgical spinal outcomes. A study team from Nashville (USA) set out to evaluate the effect of diabetes in terms of outcome measures on a whopping cohort of 1005 patients, all having undergone elective spinal surgery.² Outcomes were assessed at one and two years using general quality of life measures (SF12 and EQ-5D) as well as disease-specific outcomes (Oswestry Disability Index). The cohort had 434 diabetic patients, and these had lower SF-12, ED-5D and poorer Oswestry disability scores. Even when looking at improvement in disability, the diabetic patients didn’t fare as well as their non-diabetic control group. The diabetic patients did however make substantial improvements in both quality of life and disability scores. Whilst diabetic patients in this series do not fare as well as their normal counterparts, and that in itself is important information, they do still make substantial improvements following spinal surgery and it is certainly possible that the restriction in improvement of outcome scores is due to other sequelae of diabetes.

Scoliosis combined or posterior approach?

There is some controversy about the use of the combined anterior-posterior approach in treating idiopathic scoliosis. Whilst the plain posterior approach has the obvious benefits of operative time, reduced blood loss, and no need to turn the patient, the correction achieved may not be as effective and therefore longer-term outcomes may be compromised. We would draw readers’ attention to this comprehensive review from Guangzhou (China) which aimed to establish what the current state of play with regards to the evidence.³ Although they were unable to find any randomised controlled trials, there were ten studies reporting the outcomes of 872 patients suitable for inclusion in the study. Unpicking the analysis, it appears that there were no differences in the overall achieved correction of cobb angle between either approach, or respiratory function (predicated FEV1). However, when looking at some of the subgroups, there were differences in the achieved release between the two approaches in the more severely-affected patients. The kyphosis angle was significantly improved in the severe group who had an anterior approach, as opposed to those who had a posterior approach alone. There were however a few advantages in favour of the posterior alone approach in the less severe patients – fewer complications, better achieved respiratory function and lower blood loss. The data strongly supports the posterior-only approach in all but the most severe of corrections, as it is possible to achieve similar coronal plane correction and percent-predicted FEV1 compared to combined anterior–posterior approach, and even does better in sagittal correction in severe AIS patients and is associated with less morbidity.

Reducing C5 palsy

Every once in a while a simple paper with a superb message comes across the editorial desks at 360. The message in this paper from Osaka (Japan) is incredibly simple.⁴ Nerve root damage during laminoplasty is likely caused by thermal damage, and using cooled irrigation reduces the incidence. In their comparative case series, the authors describe the outcomes of 800 patients all undergoing cervical laminoplasty. The first 400 patients underwent irrigation with room temperature saline and the second 400 with chilled (12°) saline. The outcomes were assessed in terms of upper limb muscle power. There was a significant decrease in the incidence of upper limb palsy (from 5.5% to 1%). Further analysis of the results with a multivariant model suggested that the other contributing factors were the side of decompression, performing a foraminotomy and the use of the room temperature saline. This is an incredibly simple, but game-changing paper. Clearly chilled irrigation is safer.

Managing malpositioned lumbosacral pedicle screws

Whilst now almost universally ubiquitous, pedicle screws do have their drawbacks. Malpositioned screws can be terribly difficult to manage, with serious complications including neurological and vascular injuries. Very little is known about the best way to manage misplaced pedicle screws – and in the heat of the moment a variety of different strategies have been employed– some well-thought through and others less so.

A research team in Hangzhou (China) has described a simple and rapid method to decide if revision surgery is needed in patients with a misplaced pedicle screw.⁵ The team based their study on 316 patients all undergoing lumbosacral pedicle screw fixation over a two-year period. The authors describe the use of their post-operative revision score for pedicle screw malpositioning (PRSPSM). In their series, a threshold of 5 was appropriate for revision surgery, and removal/repositioning of the screw. The authors recommend that serial measurements post-operatively are appropriate and as such they were able to identify five patients early requiring revision surgery, whilst ten patients with an initially elevated score (but less than 5) all went on to make a recovery with conservative treatment. This is a nice succinct paper that highlights that not all malpositioned pedicle screws need to be revised, and gives an easy score and set of criteria on which to ‘hang your hat’ when making that tricky decision.

Improving spinal nerve root imaging: diffusion tensor scanning X-ref

The MRI scan has revolutionised the evaluation of spinal pathology. As a ‘no radiation’ scan, with the ability to visualise the soft tissue pathology in the spinal canal, it is now gold standard. There are however a few problems, the false positive rate can be as high as 30%, and so clinical correlation is still key to successful surgical outcomes. Diffusion tensor imaging (dMRI) is an MRI technique that uses the diffusion patterns of water to detect abnormalities in soft tissues. dMRI has been in common use in stroke management and was developed in the mid-1980s. It is somewhat surprising then that dMRI has not found application in spinal pathology. Researchers from Chiba (Japan) present the first series, although small, of the application of this technology to 13 patients, all with a symptomatic disc prolapse.⁶ Their diagnostic paper considers the imaging results of these patients obtained on a 1.5T MRI scanner with dMRI imaging and attempts to establish what the changes in specific diffusion parameters were (fractional anisotropy (FA) and apparent diffusion coefficient (ADC)). Scans were taken both at presentation and six months following surgery, with the imaging findings correlated to the reported symptomatology. The authors established that the FA values significantly decreased and the ADC values significantly increased in compressed nerve roots and that there were strong correlations between reported symptoms and the dMRI findings. It does appear that the flexibility offered by dMRI may allow for better understanding of imaging findings, and perhaps in the future increase the specificity of MRI scanning as a diagnostic modality.

Cervival myelopathy and PLL ossification

Getting a handle on exactly what is meant by cervical myelopathy can be challenging. Like many umbrella terms, degenerative cervical myelopathy is a broad church covering a variety of pathologies. The range of pathologies includes spondylotic changes as well as PLL thickening and ossification. An international study team from Canada, Japan, USA and China coordinated as part of the AO Foundation asked the question: is surgery equally effective and safe in patients with PLL ossifications as it is in other pathologies relating to cervical myelopathy?⁷ Their study included the outcomes of 479 patients all with symptomatic cervical myelopathy enrolled at 16 international sites to take part in this prospective study. The study reports comparative surgical outcomes between those patients with ossification of the PLL and those without. Outcomes were reported with clinical outcome scores and the SF-36 quality of life scores. The groups were unsurprisingly unequal, with 135 patients presenting with radiographic evidence of PLL ossification and 344 without. There were no significant differences however in patient demographics or baseline disease severity between the two groups. At the final reported two-year follow-up, there were no differences in functional outcomes or quality of life scores between any of the outcome measures recorded. The authors raise a slight note of caution with a non-significant difference in complication rates with a higher rate of complications in the PLL ossification group. It seems from the data presented here that surgical decompression of cervical myelopathy secondary to PLL ossification is as successful as for any other cause, but caution should be exercised with regards to complications.