Spondylodiscitis in end-stage renal disease: a systematic review

OBJECTIVE

Discitis and osteomyelitis are seen in end-stage renal disease (ESRD) patients due to repeated vascular access for hemodialysis and urinary tract infections leading to recurrent bacteremia. Discitis and osteomyelitis are underdiagnosed due to the nonspecific initial presentation of back pain. In this article, we review the literature for better understanding of the problem and the importance of early diagnosis by primary care physicians and nephrologists. In addition, we discuss the decision-making, follow-up, management, and neurological outcomes.

METHODS

A detailed PubMed search was performed using the following terms: "end stage renal disease (ESRD)" and "chronic renal failure (CRF)," combined with "spine infections," "spondylodiscitis," "discitis," and "osteomyelitis." Search results were limited to articles written in English, case reports, and case series from 1973 to 2012. Editorials, reviews, and commentaries were excluded. Only studies involving human patients were included. The authors also included 4 patients from their own patient population.

RESULTS

A total of 30 articles met the inclusion criteria. Including the 4 patients from the authors' patient population, 212 patients with spine infections and maintenance dialysis were identified. The patients' ages ranged from 38 to 78 years. The duration of dialysis ranged from a few days to 16 years. The time from onset of back pain to diagnosis ranged from 3 days to 6 months. The most common causative organism was Staphylococcus aureus, followed by Staphylococcus epidermidis and gram-negative bacteria. Most of the patients were treated with antibiotics alone (76.8%), although surgery was indicated when patients presented with neurological deficits (p < 0.011). Approximately one-quarter of the patients developed neurological deficits, with devastating consequences. Fever and neurological deficits at presentation, culture positive for methicillin-resistant S. aureus, and age > 65 years were highly correlated with mortality in our analysis.

CONCLUSIONS

Several risk factors lead to failure of antibiotics and progression of disease in patients with ESRD. Challenges to diagnosis include vague presenting symptoms, co-existing destructive spondyloarthropathy, poor immune response, chronic elevations of inflammatory markers, and recurrent bacteremia. Infectious processes are more likely to cause permanent neurological deficits than transient deficits. The authors recommend close observation and serial imaging of these patients for early signs of neurological deficits. Any signs of disease progression will require aggressive surgical debridement.

Feasibility of Human Neural Stem Cell Transplantation for the Treatment of Acute Subdural Hematoma in a Rat Model: A Pilot Study

Human neural stem cells (hNSCs) transplantation in several brain injury models has established their therapeutic potential. However, the feasibility of hNSCs transplantation is still not clear for acute subdural hematoma (ASDH) brain injury that needs external decompression. Thus, the aim of this pilot study was to test feasibility using a rat ASDH decompression model with two clinically relevant transplantation methods. Two different methods, in situ stereotactic injection and hNSC-embedded matrix seating on the brain surface, were attempted. Athymic rats were randomized to uninjured or ASDH groups (F344/NJcl-rnu/rnu, n = 7-10/group). Animals in injury group were subjected to ASDH, and received decompressive craniectomy and 1-week after decompression surgery were transplanted with green fluorescent protein (GFP)-transduced hNSCs using one of two approaches. Histopathological examinations at 4 and 8 weeks showed that the GFP-positive hNSCs survived in injured brain tissue, extended neurite-like projections resembling neural dendrites. The in situ transplantation group had greater engraftment of hNSCs than matrix embedding approach. Immunohistochemistry with doublecortin, NeuN, and GFAP at 8 weeks after transplantation showed that transplanted hNSCs remained as immature neurons and did not differentiate toward to glial cell lines. Motor function was assessed with rotarod, compared to control group (n = 10). The latency to fall from the rotarod in hNSC in situ transplanted rats was significantly higher than in control rats (median, 113 s in hNSC vs. 69 s in control, P = 0.02). This study first demonstrates the robust engraftment of in situ transplanted hNSCs in a clinically-relevant ASDH decompression rat model. Further preclinical studies with longer study duration are warranted to verify the effectiveness of hNSC transplantation in amelioration of TBI induced deficits.

Fish-Mouth Thoracic Fracture Fixation with Minimally Invasive Percutaneous Reduction: A Technical Note

BACKGROUND

Surgical stabilization of thoracic spine fractures is recommended for unstable patterns, yet much debate exists regarding the best approach for reduction. The aim of this article was to report the outcome of a novel method for stabilization of a fish-mouth thoracic spine fracture.

METHODS

A retrospective patient chart review was conducted. Data collected included blood loss, operative time, length of stay, perioperative complications, neurologic deficits, and secondary procedures. The patient underwent percutaneous reduction of a hyperextension injury to the thoracic spine. Sufficient reduction was achieved through a percutaneous approach, followed by sequential distraction of 1 rod with sequential locking of the contralateral rod to maintain deformity correction. Electrophysiologic monitoring was used during the procedure.

RESULTS

Sufficient fracture reduction was achieved and evaluated on postoperative computed tomography. Operative time was 145 minutes, and estimated blood loss was 120 mL. There were no cerebrospinal fluid leaks, iatrogenic neurologic deficits, implant failures, other systemic events or revisions during the 8-month follow-up.

CONCLUSIONS

This article describes the feasibility of using a novel model for reduction and stabilization of fish-mouth thoracic spine fracture with minimal soft tissue violation.

Transdural approach to resection of retro-odontoid cysts in elderly patients: report of 3 cases

Retro-odontoid cysts that arise from the tectorial membrane are uncommon lesions that can occur in elderly patients. They arise secondary to degenerative changes, including calcium pyrophosphate deposition within the ligaments. Surgical treatment is indicated when these lesions result in intractable pain, instability, and/or myelopathy. Several surgical techniques to treat this condition exist, but the optimal approach in elderly patients with comorbidities remains controversial. Here, the authors present a case series of 3 patients who underwent successful resection of a retro-odontoid lesion performed through a transdural approach.

The patients were 70, 81, and 74 years old and presented with symptoms of cervical myelopathy. In consideration of their advanced age and the location of their lesion, resection via a posterior approach was considered. A 1- to 2-cm suboccipital craniectomy and C-1 and partial C-2 laminectomy were performed. These lesions could not be accessed via an extradural posterolateral approach, and so a transdural approach was performed. In the first 2 patients, a preexisting deformity prompted an instrumented fusion. In the third patient, only a lesion resection was performed. In each case, the dural opening was made using a paramedian ipsilateral-sided incision, and the lesion was resected through an incision in the anterior dura mater. Only the posterior dura was closed primarily. MR imaging evidence of excellent spinal cord decompression was evident in follow-up examinations.

Transdural resection of retro-odontoid cysts is a viable option for treating asymmetrical ventral extradural cysts. Results from this case series suggest that such an approach is safe and feasible and can provide an alternative to open or endoscopic anterior transpharyngeal approaches.

Indeterminate Dendritic Cell Tumor in Thoracic Spine: A Case Report

BACKGROUND

Indeterminate dendritic cell tumor (IDCT) is an extremely rare hematologic disorder with poorly understood pathogenesis. Occasionally encountered by hematologists, unusual presentations of IDCT have not been reported in the spine literature.

METHODS

We report a 51-year-old man who presented with a 3-month history of progressively worsening axial thoracic back pain radiating to his sides. Magnetic resonance imaging revealed a 3-cm enhancing mass at the T9 vertebral body with an exophytic component causing significant canal stenosis. Initial percutaneous biopsy revealed histiocytic sarcoma.

RESULTS

The patient underwent exploratory thoracotomy and en bloc resection of the lesion with T8-10 fusion. Final pathology results revealed IDCT with fibrosis. IDCT immunostaining was partially positive for Langerhans cell marker (positive for S100 and CD1a, but lacked Birbeck granules and Langerin stain) and partially positive for blastic plasmacytoid dendritic cell neoplasm. Additionally, it was positive for CD45, CD68, and CD163. Lymphadenopathy was absent in this patient.

CONCLUSIONS

Although first reported in the 1980s, IDCT has been omitted from most classifications owing to its rarity. Hematologists have debated the cell of origin; it is believed to comprise pre-Langerhans cells, as Birbeck granules are acquired after migration to the epidermis. IDCT remains of indeterminate origin. We report the first case of spinal IDCT. Familiarity with the histologic features is warranted to ensure accurate diagnosis and appropriate treatment.

Trends in Open and Endoscopic Cubital Tunnel Release in the Medicare Patient Population

BACKGROUND

Cubital tunnel syndrome (CUT) is the second most common peripheral neuropathy with an annual incidence of 24.7 per 100 000, affecting nearly twice as many men as women. With increasing focus on cost-effectiveness and cost-containment in medicine, a critical understanding of utilization of health care resources for open and endoscopic approaches for cubital tunnel release is of value. The purpose of this study was to evaluate the costs and utilization trends of open and endoscopic cubital tunnel release.

METHODS

We performed a retrospective review of a Medicare database within the PearlDiver Supercomputer (Warsaw, Indiana) for procedures performed from 2005 to 2012. Annual utilization, charges, reimbursement, demographic data, and compound annual growth rate were evaluated.

RESULTS

Our query returned 262 104 patients with CUT, of which 69 378 (26.5%) and 4636 (1.8%) were surgically managed with open and endoscopic release respectively. Average charges were higher in endoscopic release ($3798) than open release ($3197) while reimbursements were higher in open releases ($1041) than endoscopic release, ($866). Both were performed most commonly in the <65 years age range.

CONCLUSIONS

Despite the unexpectedly lower reimbursement rate with endoscopic release, endoscopy utilization is growing faster than open releases in the Medicare population. Lower reimbursement is likely related to lack of a dedicated current procedural terminology code for endoscopic cubital tunnel release.

Augmented-reality integrated robotics in neurosurgery: are we there yet?

Surgical robots have captured the interest—if not the widespread acceptance—of spinal neurosurgeons. But successful innovation, scientific or commercial, requires the majority to adopt a new practice. “Faster, better, cheaper” products should in theory conquer the market, but often fail. The psychology of change is complex, and the “follow the leader” mentality, common in the field today, lends little trust to the process of disseminating new technology. Beyond product quality, timing has proven to be a key factor in the inception, design, and execution of new technologies. Although the first robotic surgery was performed in 1985, scant progress was seen until the era of minimally invasive surgery. This movement increased neurosurgeons’ dependence on navigation and fluoroscopy, intensifying the drive for enhanced precision. Outside the field of medicine, various technology companies have made great progress in popularizing co-robots (“cobots”), augmented reality, and processor chips. This has helped to ease practicing surgeons into familiarity with and acceptance of these technologies. The adoption among neurosurgeons in training is a “follow the leader” phenomenon, wherein new surgeons tend to adopt the technology used during residency. In neurosurgery today, robots are limited to computers functioning between the surgeon and patient. Their functions are confined to establishing a trajectory for navigation, with task execution solely in the surgeon’s hands. In this review, the authors discuss significant untapped technologies waiting to be used for more meaningful applications. They explore the history and current manifestations of various modern technologies, and project what innovations may lie ahead.

Early experience with endoscopic foraminotomy in patients with moderate degenerative deformity

OBJECTIVE Asymmetrical degeneration of the disc is one of the most common causes of primary degenerative scoliosis in adults. Coronal deformity is usually less symptomatic than a sagittal deformity because there is less expenditure of energy and hence less effort to maintain upright posture. However, nerve root compression at the fractional curve or at the concave side of the main curve can give rise to debilitating radiculopathy. METHODS This study was a retrospective analysis of 16 patients with coronal deformity of between 10° and 20°. All patients underwent endoscopic foraminal decompression surgery. The pre- and postoperative Cobb angle, visual analog scale (VAS), 36-Item Short Form Health Survey (SF-36), and Oswestry Disability Index scores were measured. RESULTS The average age of the patients was 70.0 ± 15.5 years (mean ± SD, range 61-86 years), with a mean followup of 7.5 ± 5.3 months (range 2-14 months). The average coronal deformity was 16.8° ± 4.7° (range 10°-41°). In 8 patients the symptomatic foraminal stenosis was at the level of the fractional curve, and in the remaining patients it was at the concave side of the main curve. One of the patients included in the current cohort had to undergo a repeat operation within 1 week for another disc herniation at the adjacent level. One patient had CSF leakage, which was repaired intraoperatively, and no further complications were noted. On average, preoperative VAS and SF-36 scores showed a tendency for improvement, whereas a dramatic reduction of VAS, by 65% (p = 0.003), was observed in radicular leg pain. CONCLUSIONS Patients with mild to moderate spinal deformity are often compensated and have tolerable levels of back pain. However, unilateral radicular pain resulting from foraminal stenosis can be debilitating. In select cases, an endoscopic discectomy or foraminotomy enables the surgeon to decompress the symptomatic foramen with preservation of essential biomechanical structures, delaying the need for a major deformity correction surgery.

Early experience with endoscopic revision of lumbar spinal fusions

Approximately half a million spinal fusion procedures are performed annually in the US. It is estimated that up to one-third of arthrodesis constructs require revision surgeries. In this study the authors present endoscopic treatment strategies targeting 3 types of complications following arthrodesis surgery: 1) adjacent-level foraminal stenosis; 2) foraminal stenosis at an arthrodesis segment; and 3) stenosis caused by a displaced interbody cage. A retrospective chart review of 11 patients with a mean age of 68 ± 15 years was performed (continuous variables are shown as the mean ± SEM). All patients had a history of lumbar arthrodesis surgery and suffered from unilateral radiculopathy. Endoscopic revision surgeries were done as outpatient procedures, and there were no intraoperative or perioperative complications. The cohort included 3 patients with foraminal stenosis at the level of previous arthrodesis. They presented with unilateral radicular leg pain (visual analog scale [VAS] score: 7.3 ± 2.1) and were severely disabled, as evidenced by an Oswestry Disability Index (ODI) of 46 ± 4.9. Transforaminal endoscopic foraminotomies were performed, and at a mean follow-up time of 9.0 ± 2.5 months VAS was reduced by an average of 6.3. The cohort also includes 7 patients suffering unilateral radiculopathy due to adjacent-level foraminal stenosis. Preoperative VAS for leg pain of the symptomatic side was 6.0 ± 1.6, VAS for back pain was 5.2 ± 1.7, and ODI was 40 ± 6.33. Endoscopic decompression led to reduction of the ipsilateral leg VAS score by an average of 5, resulting in leg pain of 1 ± 0.5 at an average of 8 months of follow-up. The severity of back pain remained stable (VAS 4.2 ± 1.4). Two of these patients required revision surgery for recurrent symptoms. Finally, this study includes 1 patient who presented with weakness and pain due to retropulsion of an L5/S1 interbody spacer. The patient underwent an endoscopic interlaminar approach with partial resection of the interbody cage, which resulted in complete resolution of her radicular symptoms. Endoscopic surgery may be a useful adjunct for management of certain arthrodesis-related complications. Endoscopic foraminal decompression of previously fused segments and resection of displaced interbody cages appears to have excellent outcomes, whereas decompression of adjacent segments remains challenging and requires further investigation.

Surgical outcomes of elderly patients with cervical spondylotic myelopathy: a meta-analysis of studies reporting on 2868 patients

OBJECTIVE

Cervical spondylotic myelopathy usually presents in the 5th decade of life or later but can also present earlier in patients with congenital spinal stenosis. As life expectancy continues to increase in the United States, the preconceived reluctance toward operating on the elderly population based on older publications must be rethought. It is a known fact that outcomes in the elderly cannot be as robust as those in the younger population. There are no publications with detailed meta-analyses to determine an acceptable level of outcome in this population. In this review, the authors compare elderly patients older than 75 years to a nonelderly population, and they discuss some of the relevant strategies to minimize complications.

METHODS

In accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, the authors performed a PubMed database search to identify English-language literature published between 1995 and 2015. Combinations of the following phrases that describe the age group (“elderly,” “non-elderly,” “old,” “age”) and the disease of interest as well as management (“surgical outcome,” “surgery,” “cervical spondylotic myelopathy,” “cervical degenerative myelopathy”) were constructed when searching for relevant articles. Two reviewers independently assessed the outcomes, and any disagreement was discussed with the first author until it was resolved. A random-effects model was applied to assess pooled data due to high heterogeneity between studies. The mean difference (MD) and odds ratio were calculated for continuous and dichromatic parameters, respectively.

RESULTS

Eighteen studies comprising elderly (n = 1169) and nonelderly (n = 1699) patients who received surgical treatment for cervical spondylotic myelopathy were included in this meta-analysis. Of these studies, 5 were prospective and 13 were retrospective. Intraoperatively, both groups required a similar amount of operation time (p = 0.35). The elderly group had lower Japanese Orthopaedic Association (JOA) scores (MD −1.36, 95% CI −1.62 to −1.09; p < 0.00001) to begin with compared with the nonelderly group. The nonelderly group also had a higher postoperative JOA score (MD −1.11, 95% CI −1.44 to −0.79; p < 0.00001), therefore demonstrating a higher recovery rate from surgeries (MD −11.98, 95% CI −16.16 to −7.79; p < 0.00001). The length of stay (MD 4.14, 95% CI 3.54–4.73; p < 0.00001) was slightly longer in the elderly group. In terms of radiological outcomes, the elderly group had a smaller postoperative Cobb angle but a greater increase in spinal canal diameter compared with the nonelderly group. The complication rates were not significant.

CONCLUSIONS

Cervical myelopathy is a disease of the elderly, and age is an independent factor for recovery from surgery. Postoperative and long-term outcomes have been remarkable in terms of improvement in mobility and independence requiring reduced nursing care. There is definitely a higher potential risk while operating on the elderly population, but no significant difference in the incidence of postoperative complications was noted. Withholding surgery from the elderly population can lead to increased morbidity due to rapid progression of symptoms in addition to deconditioning from lack of mobility and independence. Reduction in operative time under anesthesia, lower blood loss, and perioperative fluid management have been shown to minimize the complication rate. The authors request that neurosurgeons weigh the potential benefit against the risks for every patient before withholding surgery from elderly patients.

Transforaminal endoscopic discectomy to relieve sciatica and delay fusion in a 31-year-old man with pars defects and low-grade spondylolisthesis

Isthmic spondylolisthesis due to pars defects resulting from trauma or spondylolysis is not uncommon. Symptomatic patients with such pars defects are traditionally treated with a variety of fusion surgeries. The authors present a unique case in which such a patient was successfully treated with endoscopic discectomy without iatrogenic destabilization.

A 31-year-old man presented with a history of left radicular leg pain along the distribution of the sciatic nerve. He had a disc herniation at L5/S1 and bilateral pars defects with a Grade I spondylolisthesis. Dynamic radiographic studies did not show significant movement of L-5 over S-1. The patient did not desire to have a fusion. After induction of local anesthesia, the patient underwent an awake transforaminal endoscopic discectomy via the extraforaminal approach, with decompression of the L-5 and S-1 nerve roots. His preoperative pain resolved immediately, and he was discharged home the same day. His preoperative Oswestry Disability Index score was 74, and postoperatively it was noted to be 8. At 2-year follow-up he continued to be symptom free, and no radiographic progression of the listhesis was noted.

In this case preservation of stabilizing structures, including the supraspinous and interspinous ligaments and the facet capsule, may have reduced the likelihood of iatrogenic instability while at the same time achieving symptom control. This may be a reasonable option for select patient symptoms confined to lumbosacral radiculopathy.

Pooled data analysis on anterior versus posterior approach for rheumatoid arthritis at the craniovertebral junction

OBJECT

Rheumatoid arthritis (RA) is one of the most debilitating autoimmune diseases affecting the craniovertebral junction (CVJ). Patients predominantly present with myelopathic symptoms and intractable neck pain. The surgical approach traditionally has been either a combined anterior and posterior approach or a posterior-only approach. In this article, the authors review pooled data from the literature and discuss the benefits of the two types of approaches.

METHODS

A search of the PubMed database was conducted using key words that describe spine deformities in RA and specific spinal interventions. The authors evaluated the neurological outcomes based on the Ranawat scale in both the groups through chi-square analysis. Multiple logistic regression was carried out to further examine for potential confounders. Any adverse sequalae resulting from either approach were also documented. Because all the procedures performed via a transoral approach in the analyzed articles also involved posterior fixation, for convenience of comparison, the combined procedures are referred to as "anterior approach" or "anterior-posterior" in the present study.

RESULTS

The search yielded 233 articles, of which 11 described anterior approaches and 14 evaluated posterior approaches. The statistical analysis showed that patients treated with a posterior approach fared better than those treated with an anterior (combined) approach. It was noted that those patients in whom the cervical subluxations were reducible on traction predominantly underwent posterior approaches.

CONCLUSIONS

CVJ instability is a serious complication of RA that requires surgical intervention. Although the anterior-posterior combined approach can provide direct decompression, it is associated with morbidity, and the analysis showed no statistically significant benefit to patients. In contrast, the posterior approach has been shown to provide statistically significant superiority with respect to stabilization and subsequent pannus reduction. Surgical approaches are undertaken based on the reducibility of subluxations with traction and the vector of compressive force. However, the choice of surgical approach should be based on the individual patient's pathology.

Reconstruction of open wounds as a complication of spinal surgery with flaps: a systematic review

OBJECT

A systematic review of the available evidence on the prophylactic and therapeutic use of flaps for the coverage of complex spinal soft-tissue defects was performed to determine if the use of flaps reduces postoperative complications and improves patient outcomes.

METHODS

A PubMed database search was performed to identify English-language articles published between 1990 and 2014 that contained the following phrases to describe postoperative wounds (“wound,” “complex back wound,” “postoperative wound,” “spine surgery”) and intervention (“flap closure,” “flap coverage,” “soft tissue reconstruction,” “muscle flap”).

RESULTS

In total, 532 articles were reviewed with 17 articles meeting the inclusion criteria of this study. The risk factors from the pooled analysis of 262 patients for the development of postoperative complex back wounds that necessitated muscle flap coverage included the involvement of instrumentation (77.6%), a previous history of radiotherapy (33.2%), smoking (20.6%), and diabetes mellitus (17.2%). In patients with instrumentation, prophylactic coverage of the wound with a well-vascularized flap was shown to result in a lower incidence of wound complications. One study showed a statistically significant decrease in complications compared with patients where prophylactic coverage was not performed (20% vs 45%). The indications for flap coverage after onset of wound complications included hardware exposure, wound infection, dehiscence, seroma, and hematoma. Flap coverage was shown to decrease the number of surgical debridements needed and also salvage hardware, with the rate of hardware removal after flap coverage ranging from 0% to 41.9% in 4 studies.

CONCLUSIONS

Prophylactic coverage with flaps in high-risk patients undergoing spine surgery reduces complications, while therapeutic coverage following wound complications allows the salvage of hardware in the majority of patients.

Stem cells for therapy in TBI

While the pace of traumatic brain injury (TBI) research has accelerated, the treatment options remain limited. Clinical trials are yet to yield successful treatment options, leading to innovative strategies to overcome the severe debilitating consequences of TBI. Stem cells may act as a potential treatment option. They have two key characteristics, the ability of self-renewal and the ability to give rise to daughter cells, which in the case of neural stem cells (NSCs) includes neurons, astrocytes and oligodendrocytes. They respond to the injury environment providing trophic support and have been shown to differentiate and integrate into the host brain. In this review, we introduce the notion of an NSC and describe the two neurogenic niches in the mammalian brain. The literature supporting the activation of an NSC in rodent models of TBI, both in vivo and in vitro, is detailed. This endogenous activation of NSCs may be augmented by exogenous transplantation of NSCs. Delivery of NSCs to assist the host nervous system has become an attractive option, with either fetal or adult NSC. This has resulted in cognitive and functional improvement in rodents, and current animal studies are using human NSCs. While no NSC clinical trials are currently ongoing for TBI, this review touches upon other neurological diseases and discuss how this may move forward into TBI.