Spine

Cement or screws?

Unpicking proximal junction kyphosis

Proximal junctional kyphosis (PJK) is a consequence of spinal fusion, and compromises the sagittal balance of the spine with all its subsequent effects. It occurs in about 30% of spinal fusion patients, and can result in the need for further intervention. The question, however, is why does it occur? Despite a number of studies investigating risk factors for the phenomenon, it is still relatively poorly understood. Here at 360 we were delighted to see a group from Shijiazhuang (China) tackling this issue extremely effectively and bringing clarity to this enigmatic condition.² The study team conducted a meta-analysis with the aim of establishing the risk factors for PJK. The team were able to include the results of 2215 patients reported from 14 different studies in their meta-analysis, following an appropriate and extensive literature search. They established that there is a significant association between PJK and fusion surgery: an age of > 55 years at time of surgery; fusion including S1, T5-T12; kyphosis exceeding 40°; low bone mineral density; and an SVA greater than 5 cm. Gender, combined anterioposterior surgery, use of a pedicle screw at the cranial most fixation point, hybrid instrumentation and thoracoplasty showed no association. While this study doesn’t cover paediatrics, and potentially leaves several synonyms excluded from the search, the paper nonetheless quantifies the associations of PJK with differing types of fusion procedure. Being a meta-analysis, it suffers from the flaws inherent in the source studies, however, perhaps a more important weakness emerges – difficulties with clearly establishing the underlying diagnosis on the incidence of PJK. More work is likely needed here.

Diagnosing lumbar spinal stenosis

Lumbar spinal stenosis (LSS) is seen in every clinic. Waiting rooms are overflowing with flexed-leg patients in pain, awaiting our remedies. Somewhere between 9% and 47% of adults suffer with LSS, particularly those over 65 years of age. Yet the clinical features that reliably describe a diagnosis of LSS have not been identified, and perhaps equally importantly, a reliable, international definition has not been reached from which to work. A team from Calgary, Alberta (Canada) has reported the results of their Delphi exercise to create a definitive and agreed list of clinical features that make up an LSS diagnosis.³ Although Delphi exercises are time-consuming and not exactly the most interesting of research methods, they are essential in areas of contention such as this, and an agreed definition can help in improving time to diagnosis, cost-effectiveness and treatment. There were 279 clinicians involved in the Delphi process, with representation from an array of professions and countries. The Delphi process ran over five rounds covering three phases, encompassing views from orthopaedics, neurosurgery, vascular surgery, physiotherapy and radiology. Finalised by a task force focus group in 2015, the International Society for the Study of the Lumbar Spine agreed a list of seven ‘history items’ which, if present, are 80% likely to give a reliable LSS diagnosis: leg and buttock pain when walking; flexing forward to relieve symptoms; relief when riding a bicycle or using a shopping trolley; motor or sensory disturbance when walking; normal and symmetrical foot pulses; lower extremity weakness; and low back pain. Although an inventory of symptoms is not exactly revolutionary and consists of a range of well-identified but potentially general features, the study does a sterling job of convincing us that a reliable clinical diagnosis is possible. Can it replace radiology? Clearly this is unlikely, but every study that helps us narrow down a diagnosis early in the presentation is helpful. Perhaps the most useful place for a study such as this is in primary care. With the pressure to avoid referral and the use of ‘triage’ centres, the addition of carefully constructed symptom inventories is going to become increasingly essential in ensuring the correct patients make it to the specialist waiting room.

Are high-heeled shoes a whole body problem?

The perils of high-heeled shoes are well known to the trauma and foot and ankle fraternities, with high expectations of function from their wearers and a surprising number of fractures to their name. The problems with the spine caused by wearing them for long periods are well known to committed high-heelers, however, they are still a bit of a mystery to the medical fraternity. It is thought that high heels can exacerbate hallux valgus in predisposed individuals; they certainly aggravate hallux rigidus and they can also markedly increase the incidence of back and neck pain when compared with the general population. A study team from Zurich (Switzerland)⁴ has set the investigation into the effect of high heels on the sagittal balance of the spine firmly in their sights. The study aims to evaluate the spine and whole body balance in young women who were not regular high heel wearers. The team used postural analysis to investigate the effects of high heel wear on a complete range of spinal parameters including C7 vertical axis, cervical lordosis, lumbar lordosis, pelvic tilt and sacral slope, none of which changed with the addition of high heels. However, there was a significant increase in knee and ankle plantar flexion. In a subgroup of patients who did not compensate with as much knee flexion, the compensation occurred with increased cervical lordosis (Δ 5.8° ± 10.7° vs 1.8° ± 5.3°). The authors have suggested that an explanation may well be that as high heel wearers age, the changes in knee flexion and the resultant cervical lordosis needed to maintain sagittal balance might explain the differing patterns of reported neck, back and knee pain. Clearly the treatment for committed high heel wearers wanting surgical perfection is footwear advice and careful discharge, however, what this study can tell us about sagittal plane spinal balance and how it interacts with the limbs is hugely important in understanding the dynamic balance of the limbs and spine in a range of pathologies.

Is spinal imaging associated with cancer?

O-arm in the paediatric spine

Can Risser stage predict effectiveness of bracing?

Reversible neurophysiological events really are reversible

In a straightforward and reassuring study, investigators in Philadelphia, Pennsylvania (USA) have reported their experience with intra-operative neurophysiological monitoring of scoliosis correction.⁸ Their study reports the outcomes of 676 patients divided into two cohorts: those who did have an intra-operative drop (n = 36) and those who did not. An event was defined as a 50% or greater drop in either somatosensory-evoked potentials or in transcranial motor-evoked potentials. These patients that experienced an event were characterised by a pre-operative larger deformity, longer operation duration, more levels of instrumentation and a higher blood loss with a greater volume of autologous blood transfused. With a return of normal potentials, 34 of the 36 patients had their surgery completed with a similar correction to those patients who did not experience an event. The eventual outcomes measured using the Scoliosis Research Society (SRS)-22 outcome scores were comparable between the two groups. Intra-operative monitoring should be considered the standard of care for scoliosis patients, and this paper illustrates the value of this technique, allowing 34 of the 36 patients to undergo their corrective surgery without compromise to their outcomes.