Monish M. Maharaj

Indirect foraminal decompression after anterior lumbar interbody fusion: a prospective radiographic study using a new pedicle-to-pedicle technique

BACKGROUND CONTEXT A frequently quoted advantage of anterior lumbar interbody fusion (ALIF) is indirect foraminal decompression, although there are few studies substantiating this statement. Also, there are no clinical studies using a standardized method to measure the foraminal area (FA) and the correlation with disc height (DH) parameters. This study is proposed to measure the degree of indirect foraminal decompression radiologically using a standardized method and correlate with the intervertebral disc parameters. PURPOSE To standardize the foramen measurement technique. To measure indirect neural foraminal decompression in surgically operated patients after ALIF using radiographic measurement and elucidate factors affecting foraminal restoration. STUDY DESIGN A prospective cohort study. PATIENT SAMPLE A continuous cohort of patients undergoing ALIF surgery. OUTCOME MEASURES It included FA, foraminal height (FH), and foraminal width. METHODS This is a prospective analysis of a single surgeon series of consecutive patients undergoing an ALIF from 2011 to 2013. Pre- and postoperative computed tomography scans were used to obtain a standardized foramen snapshot using the pedicle-to-pedicle (P-P) technique, and measurements were obtained using image j software. Radiologic parameters such as DH, local disc angle (LDA), and lumbar lordosis (LL) were measured using radiographs and Surgimap software. RESULTS One-hundred forty patients with 184 levels were operated. Anterior lumbar interbody fusion resulted in a statistically significant (p<.01) improvement in foraminal dimensions (area=67%, height=21%, and width=38%). Other parameters also significantly improved, including anterior DH (90%), posterior DH (77%), LDA, and LL (6%). Posterior DH correlated significantly with FH improvement. Statistically, the P-P technique presented with high intra- and interclass reliabilities. CONCLUSIONS Anterior lumbar interbody fusion results in significant indirect foraminal decompression based on the new P-P technique. Posterior DH is a significant factor in the restoration of the FH.

Cortical Bone Trajectory for Lumbar Pedicle Screw Placement: A Review of Published Reports

There have been a number of developments in screw design and implantation techniques over recent years, including proposal of an alternative trajectory for screw fixation aimed at increasing purchase of pedicle screws in higher density bone. Cortical bone trajectory (CBT) screw insertion follows a lateral path in the transverse plane and caudocephalad path in the sagittal plane. This technique has been advocated because it is reportedly less invasive, improves screw−bone purchase and reduces neurovascular injury; however, these claims have not been supported by robust clinical evidence. The available evidence was therefore reviewed to assess the relative merits of CBT and highlight areas for further research. To this end, a search of relevant published studies reporting biomechanical, morphometric or clinical outcomes after use of CBT screws in patients with spinal pathologies was performed via six electronic databases.

Review of early clinical results and complications associated with oblique lumbar interbody fusion (OLIF)

Lumbar interbody fusion represents an effective surgical intervention for patients with lumbar degenerative diseases, spondylolisthesis, disc herniation, pseudoarthrosis and spinal deformities. Traditionally, conventional open anterior lumbar interbody fusion and posterior/transforaminal lumbar interbody fusion techniques have been employed with excellent results, but each with their own advantages and caveats. Most recently, the antero-oblique trajectory has been introduced, providing yet another corridor to access the lumbar spine. Termed the oblique lumbar interbody fusion, this approach accesses the spine between the anterior vessels and psoas muscles, avoiding both sets of structures to allow efficient clearance of the disc space and application of a large interbody device to afford distraction for foraminal decompression and endplate preparation for rapid and thorough fusion. This review aims to summarize the early clinical results and complications of this new technique and discusses potential future directions of research.

Laparotomy vs minimally invasive laparoscopic ventriculoperitoneal shunt placement for hydrocephalus: A systematic review and meta-analysis

Ventriculoperitoneal shunt (VPS) surgery is the most commonly used method for the treatment of hydrocephalus. Traditionally, distal catheters in the VPS surgery have been placed either through a standard small open laparotomy or via a laparoscopic technique. Although there are many studies demonstrating the benefits of a minimally invasive approach, limited research has directly compared the two techniques used in VPS surgery. The present meta-analysis aims to provide the first comprehensive review of all published observational studies and randomized controlled trials reporting outcomes of laparotomy and laparoscopy in VPS. Electronic searches were performed using six databases from their inception to February 2015. Relevant studies comparing conventional laparotomy and a laparoscopic video-guided approach in VPS were included. Data were extracted and analyzed according to predefined clinical endpoints. A total of ten studies were identified for inclusion in the present analysis. Results indicated that the laparoscopic technique was associated with a slight but significant reduction in operating time (∼ 10 min), a significantly lower rate of abdominal malposition, distal obstruction and distal shunt failure. There was no difference between the laparotomic and laparoscopic approaches in the length of hospital stay, complication rate, proximal shunt failure or infection rate. The present systematic review and meta-analysis demonstrated that the laparoscopic technique in VPS surgery is associated with reduced shunt failure and abdominal malposition compared to the open laparotomy technique, with no significant difference in rates of infection or other complications. The lack of studies with high levels of evidence may contribute to bias in our conclusions and the long-term relative merits require validation by further prospective, randomized studies.

Physical Activity Measured with Accelerometer and Self-Rated Disability in Lumbar Spine Surgery: A Prospective Study

Study Design Prospective observational study. Objective Patient-based subjective ratings of symptoms and function have traditionally been used to gauge the success and extent of recovery following spine surgery. The main drawback of this type of assessment is the inherent subjectivity involved in patient scoring. We aimed to objectively measure functional outcome in patients having lumbar spine surgery using quantitative physical activity measurements derived from accelerometers. Methods A prospective study of 30 patients undergoing spine surgery was conducted with subjective outcome scores (visual analog scale [VAS], Oswestry Disability Index [ODI] and Short Form 12 [SF-12]) recorded; patients were given a Fitbit accelerometer (Fitbit Inc., San Francisco, California, United States) at least 7 days in advance of surgery to record physical activity (step count, distance traveled, calories burned) per day. Following surgery, postoperative activity levels were reported at 1-, 2-, and 3-month follow-up. Results Of the 28 compliant patients who completed the full trial period, mean steps taken per day increased 58.2% (p = 0.008) and mean distance traveled per day increased 63% (p = 0.0004) at 3-month follow-up. Significant improvements were noted for mean changes in VAS back pain, VAS leg pain, ODI, and SF-12 Physical Component Summary (PCS) scores. There was no significant correlation between the improvement in steps or distance traveled per day with improvements in VAS back or leg pain, ODI, or PCS scores at follow-up. Conclusions High compliance and statistically significant improvement in physical activity were demonstrated in patients who had lumbar decompression and lumbar fusion. There was no significant correlation between improvements in subjective clinical outcome scores with changes in physical activity measurements at follow-up. Limitations of the present study include its small sample size, and the validity of objective physical activity measurements should be assessed in future larger, prospective studies.

Outcomes of percutaneous pedicle screw fixation for spinal trauma and tumours

We investigated the clinical and radiological results of percutaneous pedicle screw fixation in the management of spinal trauma and metastatic tumours. A retrospective analysis was performed on a series of 14 patients who were operated on from March 2009 to November 2011 by a single surgeon (RJM). Following a radiological review (CT scan/MRI), six patients underwent short segment fixation, while the remaining underwent long segment fixation. All patients had routine follow-ups at 4, 6, 12months, and annually thereafter. Clinical examinations were conducted preoperatively and postoperatively, and the length of operation, blood loss, and postoperative pain relief were recorded. There was a single patient with an incision site complication. The mean blood loss was 269mL. All of the parameters demonstrated no significant differences between the trauma and the tumour groups (p=0.10). The neurological power scores improved for all patients, with the largest increase being from a score of 2 to 4. At follow-up, the majority of patients had returned to their previous activities and had reduced pain scores. One patient suffered high pain levels from other medical conditions that were not related to the operation. Minimally invasive pedicle screw fixation is a suitable option for patients with spinal tumours and fractures, with acceptable safety and efficacy in this small retrospective patient series. We have seen favourable results in our patients, who have experienced an increased quality of life following their surgery.

Anterior cervical disc arthroplasty (ACDA) versus anterior cervical discectomy and fusion (ACDF): a systematic review and metaanalysis

BACKGROUND Surgical approaches are usually required in cases of severe cervical disc disease. The traditional method of anterior cervical disc fusion (ACDF) has been associated with reduced local mobility and increased occurrence of adjacent segment disease. The newer method of anterior cervical disc arthroplasty (ACDA) relies upon artificial discs of various products. Current literature is inconsistent in the comparative performance of these methods with regards to clinical, radiological and patient outcomes. METHODS Electronic databases, including OVID Medline, PubMed, Scopus, Cochrane Central Register of Controlled Trials and Cochrane Database of Systematic Reviews, were comprehensively searched to retrieve studies comparing the treatment outcomes of ACDF and ACDA. Baseline characteristics and outcome data were extracted from eligible articles. RESULTS Two hundred and fifty five articles were identified through the database searches, and after screening 28 studies were included in the systematic review and meta-analysis. A total of 4,070 patients were included (2156 ACDA, 1914 ACDF). There was no significant difference between the two groups in operation time, blood loss during operation, long-term all-complication rate and reoperation rate at the level of injury. The ACDA group had significantly better neurological outcomes, as well as a significantly lower rate of adjacent segment diseases. CONCLUSIONS Compared with ACDF, the ACDA procedure is associated with improved reoperation rate and reduction in neurological deficits amongst previously demonstrated benefits. There is heterogeneity in ACDA devices; future studies are required to investigate the impact of this technique on treatment outcomes.

Accelerometers for objective evaluation of physical activity following spine surgery

With the potential of bias from subjective evaluation scores in spine surgery, there is a need for practical and accurate quantitative methods of analysing patient recovery. In recent years, technologies such as accelerometers and global positioning systems have been introduced as potential objective measures for pain and symptoms following spine surgery. Overall, this perspective article aims to discuss and critique currently utilised methods of monitoring spine surgical outcomes. After analysing current modalities it will briefly analyse new potential methods before examining the place for accelerometers in the field of spine surgery. A literature review was performed on the use of accelerometers for objective evaluation of symptoms and disability after spine surgery, and perspectives are summarised in this article. Physical activity measurement with the use of accelerometers following spine surgery patients is practical and quantitative. The currently available accelerometers have the potential to transform the way functional outcomes from spine surgery are assessed. One key advantage is the collection of standardised objective measurements across studies. Future studies should aim to validate accelerometer data in relation to traditional measures of functional recovery, patient outcomes, and physical activity.

Histological analysis of surgical samples and a proposed scoring system for infections in intervertebral discs

Back pain remains one the most prevalent types of pain and disability worldwide. Infection is estimated to be the underlying cause in approximately 0.01% of patients. Despite recent evidence demonstrating prominent infection rates, a standardised algorithm for diagnosis of disc infection is lacking. Histopathological evaluation can aid in confirming inflammatory changes and also in identifying degenerative changes. Hence, standardising practice through a clear scoring system with regards to inflammation and degeneration may have some utility in the clinical setting. To our knowledge no such systems exist specifically for intervertebral disc infection. A literature review of current methods of scoring inflammation and degeneration in spine surgery and orthopaedic surgery was performed. Based on the current evidence, a scoring system for disc inflammatory and degenerative changes was proposed. We propose four domains for consideration: (1) granulation tissue, (2) dense fibrosis, (3) chronic inflammatory cells, and (4) neutrophil count. The non-standardised nature of diagnosing infections and degeneration in the spinal surgery literature means that this scoring system is currently of particular value. Based on a literature review, our proposed method for diagnosis incorporates a combination of histopathological criteria expected to increase diagnostic sensitivity in the setting of disc infection. Overall, scoring can be applied to surgically obtained material and integrated directly into routine pathological practice.

Unilateral Hemilaminectomy for Intradural Lesions

Unilateral hemilaminectomy (UHIL), an alternative surgical approach to intradural lesions, involves a unilateral approach to meningeal opening that provides an adequate window for tumor extraction while leaving most of the vertebral structures intact. The techniques and results of a modified hemilaminectomy technique with spinal endoscopy is discussed and limited unilateral hemilaminectomy for intradural tumors (UHIT) evaluated prospectively.