The concept of recovery kinetics: an observational study of continuous post-operative monitoring in spine surgery.

Background: The spine surgeon's understanding of an individual patient's burden of disease and functional disability in daily life is shaped by patient-reported outcome measures (PROMs). Although PROMs are useful in understanding the patient's perception of their disease, the use of PROMs constitutes a "snapshot" approach of single timepoint data capture, omitting day-to-day fluctuations in functional status. We introduce the concept of kinetics when considering continuous and objective postoperative patient monitoring with wearable sensors. Methods: A prospective single-centre series was performed using patients either undergoing lumbar decompression for lumbar spinal stenosis (LSS) (n=12), or posterior lumbar fusion for degenerative spondylolisthesis (n=12). The Oswestry Disability Index (PROM) was conducted preoperatively and 12-weeks postoperatively. During this timeframe, continuous measurements of step count and distance travelled were made using a wrist-based wearable accelerometer. Results: Over the 12-week study period, mean daily step count for all participants improved from 4,700 to 7,700 steps per day (P=0.013), following an initial dip in total steps taken. The mean daily distance travelled improved from 3,300 to 5,300 meters per day (P=0.003). Decompression group recovered at a faster rate than the fusion group. Conclusions: Although overall improvement was similar between the decompression and fusion groups, the recovery kinetics varied. The recovery kinetics approach of continuous postoperative monitoring provides additional insight to postoperative patient progress.

Two-year continuous data capture using a wearable sensor to remotely monitor the surgical spine patient: a case report.

We report the case of a 46-year-old male with long-standing low back pain who presented with a deterioration of symptoms characterised by back and right leg pain corresponding to the L4 and L5 dermatomes. An MRI scan revealed severe central and lateral recess stenosis at L4/5 secondary to a large central disc protrusion. We remotely monitored activity and general health metrics over a time-period exceeding two years. This is the first study to monitor these metrics remotely and continuously in the surgical spine patient. Over this time, he received several interventions including a spinal cord stimulator implant, and an L4/5 microdiscectomy. We tracked his fluctuating health status using the Oura Ring [objectively measuring metrics including step count, sleep patterns, heart rate (HR), heart-rate variability (HRV), and respiratory rate (RR)] and with daily self-reported scores on the Visual Analogue Scale. The Oura Ring is a convenient and lightweight wearable device that is worn on any finger. Taken together, metrics provided a comprehensive picture of deterioration and recovery, paralleling key events in the patient's history. The use of wearable devices is feasible in enabling long-term remote continuous monitoring. This may assist surgeons and rehabilitation providers in identifying early deterioration and monitoring the post-intervention course of recovery.

The role of wearable devices and objective gait analysis for the assessment and monitoring of patients with lumbar spinal stenosis: systematic review.

BACKGROUND: The purpose of this systematic review was to evaluate the accuracy and reliability of wearable devices for objective gait measurement of Lumbar Spinal Stenosis (LSS) patients, with a focus on relevant gait metrics. METHODS: Systematic searches were conducted of five electronic databases to identify studies that assessed gait metrics by wearable or portable technology. Data was collected according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement guidelines. RESULTS: Four articles were identified for inclusion in this review. The objectives, methodology and quality of the studies varied. No single gait metric was investigated in all four studies, making comparison difficult. The most relevant metrics reported included gait cycle, gait velocity, step length and cadence, which were reported in two studies. Two studies explored gait symmetry. Differences between LSS patients and normal healthy subjects are demonstrable using wearable technology. CONCLUSIONS: The measurements of gait cycle, cadence, step length, gait velocity, and number of steps with wearable devices can be used in the gait measurement of LSS patients for initial assessment, and objective outcomes following interventions. However, data and analysis are limited, and further studies are necessary to comment on reliability.

Objective monitoring of activity and Gait Velocity using wearable accelerometer following lumbar microdiscectomy to detect recurrent disc herniation.

We report a case of a 39-year-old male with sciatica who underwent an L5/S1 microdiscectomy with objective physical activity measurements performed preoperatively and continually postoperatively up to 3-month using wireless accelerometer technology linked to the surgical practice; collecting distance travelled, daily step count (DSC) and Gait Velocity (GV). Preoperative, the patient was walking with a GV of 0.97 m/s and a DSC of less than 2,500. After the first month following surgery, the patient had increased mobility, with a GV of 1.58 m/s, and taking an average of over 4,500 steps per day. At day 57 postop, the patient experienced a recurrence of pain with reduction of GV, DSC and walking distance. Magnetic resonance imaging (MRI) was performed and revealed a recurrent disc herniation with further surgery on day 63, with a rapid return of function post 2nd surgery. The use of wireless accelerometers is practical in obtaining objective physical activity measurements before and after lumbar microdiscectomy, and will assist the surgeon and rehabilitation provider to monitor outcomes, complications and assist in clinical decision making.