Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) is a relatively new surgical procedure that appears to minimize iatrogenic soft tissue and muscle injury. The authors describe a technique for MI-TLIF that permits the surgeon to reduce spondylolisthesis percutaneously. The results in 40 consecutive patients who underwent MI-TLIF for symptomatic spondylolisthesis utilizing this approach are reviewed. Thirty cases involved a degenerative spondylolisthesis while the remaining 10 were isthmic. The minimum follow-up was 24 months with a mean of 35 months. The mean preoperative Oswestry Disability Index score was 55, decreasing to a mean of 16 postoperatively. The mean leg and back pain visual analog scale scores were 65 and 52, respectively, improving to means of 8 and 15. Reduction of the spondylolisthesis was achieved in all cases, with a mean decrease in forward translation of 76%. The authors conclude that MI-TLIF for symptomatic spondylolisthesis appears to be an effective surgical option with results that compare favorably to open procedures.
Kevin S. Chen and Paul Park
This video details the minimally invasive approach for treatment of a symptomatic Grade II lytic spondylolisthesis with high-grade foraminal stenosis. In this procedure, the use of a navigated, guidewireless technique for percutaneous pedicle screw placement at the lumbosacral junction is highlighted following initial decompression and transforaminal interbody fusion. Key steps of the procedure are delineated that include positioning, exposure, technique for interbody fusion, intraoperative image acquisition, and use of a concise 2-step process for navigated screw placement without using guidewires.
The video can be found here: https://youtu.be/2u6H4Pc_8To.
Jacob R. Joseph, Brandon W. Smith, Xilin Liu and Paul Park
Surgical robotics has demonstrated utility across the spectrum of surgery. Robotics in spine surgery, however, remains in its infancy. Here, the authors systematically review the evidence behind robotic applications in spinal instrumentation.
This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Relevant studies (through October 2016) that reported the use of robotics in spinal instrumentation were identified from a search of the PubMed database. Data regarding the accuracy of screw placement, surgeon learning curve, radiation exposure, and reasons for robotic failure were extracted.
Twenty-five studies describing 2 unique robots met inclusion criteria. Of these, 22 studies evaluated accuracy of spinal instrumentation. Although grading of pedicle screw accuracy was variable, the most commonly used method was the Gertzbein and Robbins system of classification. In the studies using the Gertzbein and Robbins system, accuracy (Grades A and B) ranged from 85% to 100%. Ten studies evaluated radiation exposure during the procedure. In studies that detailed fluoroscopy usage, overall fluoroscopy times ranged from 1.3 to 34 seconds per screw. Nine studies examined the learning curve for the surgeon, and 12 studies described causes of robotic failure, which included registration failure, soft-tissue hindrance, and lateral skiving of the drill guide.
Robotics in spine surgery is an emerging technology that holds promise for future applications. Surgical accuracy in instrumentation implanted using robotics appears to be high. However, the impact of robotics on radiation exposure is not clear and seems to be dependent on technique and robot type.
Sangala Jaypal Reddy, Frank La Marca and Paul Park
Heat shock proteins (HSPs) are normal intracellular proteins that are produced in greater amounts when cells are subjected to stress or injury. These proteins have been shown to play a key role in the modulation of the secondary injury that occurs after the initial spinal cord injury (SCI). Heat shock proteins normally act as molecular chaperones and are called protein guardians because they act to repair partially damaged proteins. Normally intracellular, HSPs can also be liberated into the systemic circulation to act as important inflammatory mediators. In the setting of SCI, HSP induction has been shown to be beneficial. These proteins are liberated primarily by acutely stressed microglial, endothelial, and ependymal cells. Heat shock proteins have also been shown to assist in the protection of motor neurons and to prevent chronic inflammation after SCI. In animal models, several experimental drugs have shown neuroprotective effects in the spinal cord and appear to function by modulating HSPs.
Cheerag D. Upadhyaya, Paul Park and Frank La Marca
✓ Chyloretroperitoneum is an uncommon complication following spinal surgery. The authors present the case of a patient in whom conservative treatment and initial surgical measures failed to relieve varied symptoms of postsurgical chyloretroperitoneum. Following attempts at conservative management, a peritoneal window was surgically created to divert lymphatic flow from the retroperitoneal space into the peritoneal space, where it was resorbed. This unique surgical technique provides yet another option in the treatment of refractory chyloretroperitoneum following anterior lumbar spinal surgery. The authors describe their technique and review retroperitoneal lymphatic anatomy along with similar case reports in the literature.
Brandon W. Smith, Jacob R. Joseph and Paul Park
Heparin-induced thrombocytopenia (HIT) is a state of thrombocytopenia with a paradoxically elevated thrombotic potential after exposure to heparin. Severe cases can present with multiorgan involvement with direct and secondary effects. Although HIT has been reported following other surgeries, to the authors’ knowledge there has not been a report of HIT after spinal surgery. The present case details the course of a patient who underwent elective lumbar surgery followed by delayed presentation of shortness of breath due to multiple pulmonary embolisms and right lower-extremity paralysis due to extensive iliofemoral clot burden with acute compartment syndrome. The patient was treated with intravenous argatroban for extensive thrombosis and also required open thrombectomy and fasciotomies for treatment of compartment syndrome. Although the patient eventually experienced motor recovery, residual sensory deficits persisted at last follow-up. In this report, the pathophysiology, clinical presentation, and treatment of HIT are reviewed.
Darryl Lau, Matthew R. Leach, Frank La Marca and Paul Park
Surgery for spinal metastasis is considered palliative, and postoperative survival is often less than a year. Recurrence of metastatic lesions is quite common, and it remains unclear whether repeat surgery is effective. In this study, the authors assessed independent predictors for survival at 6 months, 1 year, and 2 years after surgery, and examined whether repeat surgery for recurrence of spinal metastasis influenced survival rates.
Retrospective review of the electronic medical records was performed to identify a consecutive population of adult patients who underwent surgery for spinal metastasis during the period 2005–2011. Utilizing a Cox proportional hazard regression model, the authors assessed independent predictors and risk factors for survival at 6 months, 1 year, and 2 years after surgery. In addition, the impact of repeat surgery on survival was specifically assessed via multivariable analysis.
A total of 99 patients were included in the final analysis. The overall mean postoperative duration of survival was 9.6 months. In addition to previously identified predictors of survival (preoperative ambulation, Karnofsky Performance Status [KPS], radiotherapy, primary cancer type, presence of extraspinal metastasis, and number of spinal segments with metastasis), pain on presentation and body mass index (BMI) of 25–30 were both independently associated with survival. Patients with recurrence who underwent repeat surgery had longer mean survival times than patients with recurrence who did not undergo repeat surgery (19.6 months vs 12.8 months, respectively). Repeat surgery was also independently associated with higher survival rates on multivariate analysis. Follow-up KPS was significantly higher in patients who underwent repeat surgery as well.
In addition to confirming previously identified predictors of survival following surgery for spinal metastasis, the authors identified BMI and pain on presentation as independent predictors of survival. They also found that repeat surgery may be a viable option in patients with metastatic recurrence and may offer prolonged survival, likely due to improved functionality, mitigating complications associated with immobility.
John E. Ziewacz, Darryl Lau, Frank La Marca and Paul Park
Leiomyosarcoma is a smooth-muscle sarcoma that rarely metastasizes to the spine. Its clinical course is variable, although patients with metastatic leiomyosarcoma can experience prolonged survival as compared with patients with more aggressive metastatic tumors. The authors report their single-institution experience in the surgical treatment of patients with leiomyosarcoma metastatic to the spine.
A retrospective review of the electronic medical records was performed to obtain details on clinical management and outcomes for patients who had undergone surgical intervention for metastatic leiomyosarcoma of the spine. The few articles available in the current literature on this topic were also analyzed.
Eight patients with metastatic leiomyosarcoma of the spine underwent surgical management between 2005 and 2011. Six patients (75%) had improvement in their Nurick grade. Patients who had presented with pain as a primary symptom experienced significant relief. Five patients (63%) had lesion recurrence, and 4 underwent repeat surgery at a mean of 10.2 months after their initial surgery. The mean duration of survival was 11.7 months (range 3.3–23.0 months).
Leiomyosarcoma rarely metastasizes to the spine. However, surgical intervention can relieve pain and improve neurological function. Given the potential for prolonged survival, aggressive management should be considered in well-selected patients.