Introduction Minimally invasive lumbar discectomy using the METRx™ System (MAST discectomy) has been advocated as an alternative to open microdiscectomy for symptomatic posterolateral lumbar disc herniation. This paper presents a quality assurance dual surgeon retrospective study with independent observer minimum twelve month follow-up.

Methods This study was approved by the Ethics Committee of the Princess Alexandra Hospital prior to commencement. All patients who underwent MAST discectomy using the METRx™ System for the management of radiculopathy caused by posterolateral lumbar disc herniation under the care of two surgeons (AN and RK) more than twelve months prior to the commencement of assessment were included in the study. The patient demographic data was collected contemporaneously, operation performance data was collected retrospectively from hospital databases and outcome data was collected by telephone interview by independent observers (PL, SO and JP) a minimum of twelve months after discharge from hospital.

Results 101 patients (53 males, 48 females) (average age 43 years, range 17 to 83 years) underwent 102 procedures between July 2001 and December 2004. Surgery was performed on the right side in 63 cases and was either at L4/5 (30%) or more commonly L5/S1 (70%). 21 were public patients and 80 private patients with 59 episodes of surgery occurring in a public hospital. 46 operations were performed with the METRx™ MED System and 56 with the METRx™ MD System. The average duration of surgery for patients at the Princess Alexandra Hospital (n = 48) was 88 minutes with an average length of post-operative hospital stay of 22 hrs 35 mins. 16 of these cases were performed as day surgery. Perioperative complications were: conversion to open (3), urine retention (7), nausea and vomiting (3), durotomy (5), wound haematoma not requiring surgery (1) and incorrect level surgery identified and rectified during surgery (1). The average length of time from surgery to independent follow-up was 679 days (range: 382 to 1055) with 78% successful contact. On the Modified McNabb Outcome Scale, 83% reported an excellent or good outcome, 9% reported a fair outcome and 8% a poor outcome. The time until return to work was identified as less than two weeks in 28% and between 2 weeks and 3 months in 39%. Patients whose surgery was funded by Workers Compensation were over-represented in both the poor outcomes and delayed return to work. 4 patients reported progressive severe low back pain, 10 patients reported ongoing lower limb pain (severe in 1 and mild in 9) and 1 patient underwent surgery for a recurrent disc prolapse. Further disc prolapse at different sites was identified in five patients.

Discussion The retrospective data in this study forms class IV evidence for efficacy. As a quality assurance exercise it suggests an acceptable level of safety and efficacy to allow further technique development and study. A prospective randomized controlled study is proposed. The high incidence of urine retention early in the series of one surgeon is considered to be related to the practice of placing depot morphine in the operative bed. The reduction in complications in general and the improvement in duration of surgery over the series is evidence of the learning curve for this procedure.

Introduction The devastating and permanent effects of complete spinal cord injury are well documented. In animal models, olfactory ensheathing cells (OEC) transplanted into areas of complete spinal cord injury have promoted regeneration of the neural elements with reconnection of the descending motor pathways. This reproducible anatomical finding is associated with significant motor functional recovery. Accordingly, cellular transplantation therapies have been advocated for human spinal cord injury.

In a single-blind, Phase I clinical trial, we aimed to test the feasibility and safety of transplantation of autologous olfactory ensheathing cells into the spinal cord of three humans with complete spinal cord injury. This paper describes the trial and the surgical procedures and presents twelve month safety data.

Methods Six patients with paraplegia resulting from chronic (6 – 36 months post-injury) traumatic spinal cord injury (thoracic) were enrolled in the trial. Exclusion criteria included the presence of vertebral column instability, syringomyelia, an implanted spinal device or instrumentation and the presence of psychological instability. The patients were allocated to a treatment group and a control group. No intervention was undertaken to the control group.

Olfactory ensheathing cells were harvested from each subject in the surgery group, grown and purified in vitro. After exposure via laminectomy, durotomy and adhesolysis, the cells were injected into the region of injured spinal cord.

All patients are tested on enrollment and then at regular intervals up to three years by a group of assessors who are blinded to the treatment or control group status. These assessments include physical, radiological, neurophysiological and psychosocial parameters.

Results All surgery patients exhibited continuity of presumed pia through the cystic region at the site of injury. The spinal cord adjacent to the cyst appeared macroscopically normal. There were no complications of surgery evident in the peri-operative period. At twelve months there was no evidence of tumour formation, syrinx development, clinical or psychosocial deterioration.

Discussion The dictum, primum non nocere, is especially relevant to the emerging field of human spinal cord regeneration. Animal models promise such exciting potentials for therapy in this devastating condition, that the possibilities need to be fully explored. Anecdotal, non-trial based reports suggest that equivalent results may be able to be obtained in humans. However, science and care should guide the endeavours in this controversial field.

This is the first reported trial of OEC’s in human spinal cord injury. Twelve-month data in a small cohort shows that there is no evidence of adverse events that would preclude completion of the current trial and the development of efficacy trials.

Introduction: Repetitive undertaking of a physical tasks results in an innate memory for that task. Development of this memory is an important component of surgical training and the ease and safety with which these changes are incorporated into a smoothly flowing procedure is represented by the so-called “learning curve”.

Changes in equipment and technology may radically alter the paradigm used by surgeons for completing the task of an operation. An example of this is the integration of endoscopy. The hand-eye orientation, field of view, angle of approach, binocularity of vision and skew of the visual field are all altered in lumbar micro-endoscopic discectomy (MED), when compared to open microdiscectomy.

Methods: This is a prospective observational study of the initial twenty-five cases of lumbar MED in the hands of a single surgeon. The twenty-five cases of open micro-discectomy immediately predating the current series are used as a cohort for comparison.

Results: A definite alteration in the ability of the surgeon to undertake a new method of discectomy occurred.

Three of the first seven cases of MED were converted to an open discectomy. None of the ensuing 18 cases was converted. The major learning outcomes to account for the change were familiarity with the radiological and videoscopic anatomy, and recognition of the importance of angles of approach.

The average time for surgery in the first ten cases was significantly longer than the second fifteen. The time for surgery in the latter group was not significantly altered from the open cohort group. The facets of surgery responsible for the increased time in the first group were techniques of exposing the nerve root, comfort of the extent of decompression of the nerve root and excision of the disc and comfort with the orientation and cleaning of the camera. The quality of illumination and visualisation of the operative field improved over the study although the significance of this could not be quantified.

Subjectively, surgeon “comfort” with the procedure developed relatively early in the “learning curve”.

There was no significant difference in clinical outcome and complications between the two groups.

Discussion: Minimal access techniques have been widely integrated into other fields of surgical endeavour. Open microdiscectomy is well accepted as a treatment for acute lumbar disc prolapse. The decision whether or not to change a surgeon’s operative technique should be based on the final anticipated clinical benefit of such a change compared to the cost and risk of changing. This study shows that there is a learning curve associated with lumbar MED, but that it can be integrated relatively easily into a surgical armamentarium.

INTRODUCTION: Repetitive undertaking of a physical task results in an innate memory for that task. Development of this memory is an important component of surgical training and the ease and safety with which these changes are incorporated into a smoothly flowing procedure is represented by the so-called “learning curve”.

Changes in equipment and technology may radically alter the paradigm used by surgeons for completing the task of an operation. An example of this is the integration of endoscopy. The hand-eye orientation, field of view, angle of approach, binocularity of vision and skew of the visual field are all altered in lumbar microendoscopic discectomy (MED), when compared to open microdiscectomy.

METHODS: This is a prospective observational study of the initial twenty-five cases of lumbar MED in the hands of a single surgeon. The twenty-five cases of open microdiscectomy immediately predating the current series are used as a cohort for comparison.

RESULTS: A definite alteration in the ability of the surgeon to undertake a new method of discectomy occurred.

Three of the first seven cases of MED were converted to an open discectomy. None of the ensuing 18 cases was converted. The major learning outcomes to account for the change were familiarity with the radiological and videoscopic anatomy, and recognition of the importance of angles of approach.

The average time for surgery in the first ten cases was significantly longer than the second fifteen. The time for surgery in the latter group was not significantly altered from the open cohort group. The facets of surgery responsible for the increased time in the first group were techniques of exposing the nerve root, comfort of the extent of decompression of the nerve root and excision of the disc and comfort with the orientation and cleaning of the camera. The quality of illumination and visualisation of the operative field improved over the study although the significance of this could not be quantified.

Subjectively, surgeon “comfort” with the procedure developed relatively early in the “learning curve”.

There was no significant difference in clinical outcome and complications between the two groups.

DISCUSSION: Minimal access techniques have been widely integrated into other fields of surgical endeavour. Open microdiscectomy is well accepted as a treatment for acute lumbar disc prolapse. The decision whether or not to change a surgeon’s operative technique should be based on the final anticipated clinical benefit of such a change compared to the cost and risk of changing. This study shows that there is a learning curve associated with lumbar MED, but that it can be integrated relatively easily into a surgical armamentarium.