Albert P. Wong

Complications of open compared to minimally invasive lumbar spine decompression

Minimally invasive modalities have demonstrated efficacy in the treatment of neurogenic claudication. Direct comparisons, however, between complication rates of these newer techniques with open surgical techniques for lumbar decompression are lacking. This single-institution study examined neurogenic claudicants between August 2007 and June 2009. A total of 26 patients received open surgical decompression, and 23 patients microendoscopic decompression. Baseline demographic characteristics, peri-operative morbidity and mortality, length of hospital stay, and final disposition following hospitalization were recorded. Morbidity was divided into major and minor categories as defined by degree of requisite intervention and adverse impact on hospital stay. Average age, number of surgical levels, and pre-operative American Society of Anesthesiologists Physical Status Index scores were similar in each group (p>0.05). While minimally invasive surgery may be associated with slightly longer operative times, there is decreased blood loss, shorter hospital stays, and likely decreased requirements for ancillary support services upon discharge.

Measuring Surgical Outcomes in Cervical Spondylotic Myelopathy Patients Undergoing Anterior Cervical Discectomy and Fusion: Assessment of Minimum Clinically Important Difference

Object The concept of minimum clinically important difference (MCID) has been used to measure the threshold by which the effect of a specific treatment can be considered clinically meaningful. MCID has previously been studied in surgical patients, however few studies have assessed its role in spinal surgery. The goal of this study was to assess the role of MCID in patients undergoing anterior cervical discectomy and fusion (ACDF) for cervical spondylotic myelopathy (CSM). Methods Data was collected on 30 patients who underwent ACDF for CSM between 2007 and 2012. Preoperative and 1-year postoperative Neck Disability Index (NDI), Visual-Analog Scale (VAS), and Short Form-36 (SF-36) Physical (PCS) and Mental (MCS) Component Summary PRO scores were collected. Five distribution- and anchor-based approaches were used to calculate MCID threshold values average change, change difference, receiver operating characteristic curve (ROC), minimum detectable change (MDC) and standard error of measurement (SEM). The Health Transition Item of the SF-36 (HTI) was used as an external anchor. Results Patients had a significant improvement in all mean physical PRO scores postoperatively (p<0.01) NDI (29.24 to 14.82), VAS (5.06 to 1.72), and PCS (36.98 to 44.22). The five MCID approaches yielded a range of values for each PRO: 2.00–8.78 for PCS, 2.06–5.73 for MCS, 4.83–13.39 for NDI, and 0.36–3.11 for VAS. PCS was the most representative PRO measure, presenting the greatest area under the ROC curve (0.94). MDC values were not affected by the choice of anchor and their threshold of improvement was statistically greater than the chance of error from unimproved patients. Conclusion SF-36 PCS was the most representative PRO measure. MDC appears to be the most appropriate MCID method. When MDC was applied together with HTI anchor, the MCID thresholds were: 13.39 for NDI, 3.11 for VAS, 5.56 for PCS and 5.73 for MCS.

Outcome following unilateral versus bilateral instrumentation in patients undergoing minimally invasive transforaminal lumbar interbody fusion: A single-center randomized prospective study

OBJECT Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) is used to treat a wide variety of lumbar degenerative disorders. Although there are some reports showing efficacy of unilateral instrumentation during MIS-TLIF, a controlled randomized prospective study has not been done. METHODS Forty-one patients were randomly assigned to receive either bilateral or unilateral instrumentation following 1-level unilateral MIS-TLIF. Four patients were lost to follow-up in the unilateral group and 1 patient was lost to follow-up in the bilateral group. Preoperative and postoperative scores on a visual analog scale (VAS) for back pain and leg pain (VAS-BP and VAS-LP, respectively), Oswestry Disability Index (ODI), and 36-Item Short Form Healthy Survey version 2 (SF-36v2) were collected. Additionally, preoperative and postoperative segmental Cobb angles and radiographic evidence of fusion were analyzed. RESULTS There was no statistically significant difference in baseline demographic characteristics between the 2 groups. The VAS-BP, VAS-LP, ODI, and SF-36v2 physical component scores improved significantly after surgery in both groups (p < 0.05); there was no statistically significant between-groups difference in the degree of improvement. Blood loss was significantly higher in the bilateral instrumentation group and hospital stay was longer in the unilateral instrumentation group. There was no statistically significant between-groups difference with respect to change in segmental lordosis or fusion rate. The average duration of follow-up was 12.4 months for the bilateral instrumentation group and 11.4 months for the unilateral instrumentation group. CONCLUSIONS Clinical and radiographic outcomes of unilateral and bilateral instrumentation for unilateral MISTLIF are similar 1 year after surgery.

The Microendoscopic Decompression of Lumbar Stenosis: A Review of the Current Literature and Clinical Results

Lumbar stenosis is a well-defined pathologic condition with excellent surgical outcomes. Empiric evidence as well as randomized, prospective trials has demonstrated the superior efficacy of surgery compared to medical management for lumbar stenosis. Traditionally, lumbar stenosis is decompressed with open laminectomies. This involves removal of the spinous process, lamina, and the posterior musculoligamentous complex (posterior tension band). This approach provides excellent improvement in symptoms, but is also associated with potential postoperative spinal instability. This may result in subsequent need for spinal fusion. Advances in technology have enabled the application of minimally invasive spine surgery (MISS) as an acceptable alternative to open lumbar decompression. Recent studies have shown similar to improved perioperative outcomes when comparing MISS to open decompression for lumbar stenosis. A literature review of MISS for decompression of lumbar stenosis with tubular retractors was performed to evaluate the outcomes of this modern surgical technique. In addition, a discussion of the advantages and limitations of this technique is provided.

Minimally Invasive Lateral Transpsoas Approach to the Lumbar Spine: Pitfalls and Complication Avoidance

The lateral transpsoas approach to the lumbar spine has become an increasingly popular method to achieve fusion. Although this approach requires less tissue dissection, a smaller incision, decreased operative time, reduced blood loss and postoperative pain, and shorter hospital stay, it carries the potential for serious neurologic and visceral complications. This article reviews these complications in detail and proposes mechanisms for their avoidance.

Evidence-based management of deep wound infection after spinal instrumentation

In this study, evidence-based medicine is used to assess optimal surgical and medical management of patients with post-operative deep wound infection following spinal instrumentation. A computerized literature search of the PubMed database was performed. Twenty pertinent studies were identified. Studies were separated into publications addressing instrumentation retention versus removal and publications addressing antibiotic therapy regimen. The findings were classified based on level of evidence (I-III) and findings were summarized into evidentiary tables. No level I or II evidence was identified. With regards to surgical management, five studies support instrumentation retention in the setting of early deep infection. In contrast, for delayed infection, the evidence favors removal of instrumentation at the time of initial debridement. Surgeons should be aware that for deformity patients, even if solid fusion is observed, removal of instrumentation may be associated with significant loss of correction. A course of intravenous antibiotics followed by long-term oral suppressive therapy should be pursued if instrumentation is retained. A shorter treatment course may be appropriate if hardware is removed.

Microendoscopic decompression for cervical spondylotic myelopathy

OBJECT Cervical spondylotic myelopathy (CSM) is a common cervical degenerative disease that affects the elderly population. Spinal cord decompression is achieved through various anterior and posterior approaches including anterior cervical decompression and fusion, laminectomy, laminoplasty, and combined approaches. The authors describe another option, minimally invasive endoscopically assisted decompression of stenosis (MEDS), which obviates the need for muscle dissection and disruption of the posterior tension band, a cause of postlaminectomy kyphosis. METHODS The authors conducted a retrospective study of 10 patients with CSM who underwent MEDS from January 2002 through July 2012. Data were collected on demographics, preoperative and postoperative Nurick scores, postoperative Odom scores, and preoperative and postoperative Cobb angles. RESULTS The mean patient age (± SD) was 67 ± 7.7 years; 8 patients were male. The average number of disc levels operated on was 2.2 (range 1-4). The mean Nurick score was 1.6 ± 0.7 preoperatively and improved to 0.3 ± 0.7 postoperatively (p < 0.0005). The postoperative Odom scores indicated excellent outcomes for 4 patients, good for 3, fair for 2, and poor for 1. The average preoperative focal Cobb angle at the disc levels operated on was -0.43º ± 1.9º. The average Cobb angle at the last follow-up visit was 0.25° ± 1.6° (p = 0.6). The average follow-up time was 18.9 ± 32.1 months. There were no intraoperative or postoperative complications. CONCLUSIONS For selected patients with CSM, whose pathologic changes are primarily posterior and who have acceptable preoperative lordosis, MEDS is an alternative to open laminectomy and laminoplasty.

Minimally invasive thoracic corpectomy: Surgical strategies for malignancy, trauma, and complex spinal pathologies

The rapid expansion of minimally invasive techniques for corpectomy in the thoracic spine provides promise to redefine treatment options in this region. Techniques have evolved permitting anterior, lateral, posterolateral, and midline posterior corpectomy in a minimally invasive fashion. We review the numerous techniques that have been described, including thoracoscopy, tubular retraction, and various instrumentation techniques. Minimally invasive techniques are compared to their open predecessors from a technical and complication standpoint. Advantages and disadvantages of different approaches are also considered, with an emphasis on surgical strategies and nuance.

Comparison of open and minimally invasive surgery for intradural-extramedullary spine tumors.

OBJECT Patients with symptomatic intradural-extramedullary (ID-EM) tumors may be successfully treated with resection of the lesion and decompression of associated neural structures. Studies of patients undergoing open resection of these tumors have reported high rates of gross-total resection (GTR) with minimal long-term neurological deficit. Case reports and small case series have suggested that these patients may be successfully treated with minimally invasive surgery (MIS). These studies have been limited by small patient populations. Moreover, there are no studies directly comparing perioperative outcomes between patients treated with open resection and MIS. The objective of this study was to compare perioperative outcomes in patients with ID-EM tumors treated using open resection or MIS. METHODS A retrospective review was performed using data collected from 45 consecutive patients treated by open resection or MIS for ID-EM spine tumors. These patients were treated over a 9-year period between April 2003 and October 2012 at Northwestern University and the University of Chicago. Statistical analysis was performed to compare perioperative outcomes between the two groups. RESULTS Of the 45 patients in the study, 27 were treated with the MIS approach and 18 were treated with the open approach. Operative time was similar between the two groups: 256.3 minutes in the MIS group versus 241.1 minutes in the open group (p = 0.55). Estimated blood loss was significantly lower in the MIS group (133.7 ml) compared with the open group (558.8 ml) (p < 0.01). A GTR was achieved in 94.4% of the open cases and 92.6% of the MIS cases (p = 0.81). The mean hospital stay was significantly shorter in the MIS group (3.9 days) compared with the open group (6.1 days) (p < 0.01). There was no significant difference between the complication rates (p = 0.32) and reoperation rates (p = 0.33) between the two groups. Multivariate analysis demonstrated an increased rate of complications in cervical spine tumors (OR 15, p = 0.05). CONCLUSIONS Thoracolumbar ID-EM tumors may be safely and effectively treated with either the open approach or an MIS approach, with an equivalent rate of GTR, perioperative complication rate, and operative time. Patients treated with an MIS approach may benefit from a decrease in operative blood loss and shorter hospital stays.

Predictors of survival in patients with spinal ependymoma

Abstract Objectives: We aimed to examine the impact of demographic and treatment factors on overall survival among spinal ependymoma patients. Methods: Using data from Surveillance, Epidemiology, and End Results (SEER) from 1990–2008, we evaluated subjects with histologically confirmed spinal cord ependymoma. Results: We identified 1,353 patients with spinal ependymoma (mean age 43.5 years). Among these, 26 had anaplastic ependymoma (AE), 374 had myxopapillary ependymoma (MPE), and 953 had other low-grade ependymoma (non-MPE). Median follow-up was 61 months. Overall survival at 5 years was 97% for MPE, 92% for low-grade non-MPE, and 73% for AE. Gross total resection (GTR) was achieved in 58% of subjects with MPE, 51% with low-grade non-MPE, and 50% with AE. Radiation occurred more often after subtotal resection (STR) than after GTR, and more often among those with anaplastic histology. Histology and extent of surgical resection were significant prognostic factors in multivariate analyses. Compared to MPE, subjects with low-grade non-MPE had a higher risk of mortality at 5 years (HR 2.35, P = 0.03), as did subjects with AE (HR 8.63, P < 0.01). Compared to GTR, STR was associated with an increased risk of mortality at 5 years (HR 2.2, P = 0.01), as was biopsy only (HR 2.05, P = 0.03) and no surgery (HR 4.97, P < 0.01). Among patients with either STR or GTR, adjuvant radiotherapy did not confer a survival benefit at 5 years (STR: HR 2.29, P = 0.07, and GTR: HR 2.2, P = 0.12). Discussion: We found that lower grade histology and higher extent of surgical resection were significant prognostic factors for more favourable survival outcomes for spinal ependymoma patients.