Stephan N. Salzmann

Lumbar disc replacement surgery—successes and obstacles to widespread adoption

Purpose of reviewLumbar disc replacement has been a surgical alternative to fusion surgery for the treatment of lumbar degenerative disc disease (DDD) for many years. Despite enthusiasm after the approval of the first devices, implantation rates have remained low, especially in the USA. The goal of this review is to provide a general overview of lumbar disc replacement in order to comprehend the successes and obstacles to widespread adoption.Recent findingsAlthough a large amount of evidence-based data including satisfactory long-term results is available, implantation rates in the USA have not increased in the last decade. Possible explanations for this include strict indications for use, challenging surgical techniques, lack of device selection, fear of late complications or revision surgeries, and reimbursement issues.SummaryRecent publications can address some of the past concerns, but there still remain obstacles to widespread adoption. Upcoming data on long-term outcome, implant durability and possible very late complications will determine the future of lumbar disc replacement surgery.

Emergent reintubation following elective cervical surgery: A case series

AIM To review cases of emergent reintubation after cervical surgery. METHODS Patients who were emergently intubated in the post-operative period following cervical surgery were identified. The patients’ prospectively documented demographic parameters, medical history and clinical symptoms were ascertained. Pre-operative radiographs were examined for the extent of their pathology. The details of the operative procedure were discerned. RESULTS Eight hundred and eighty patients received anterior- or combined anterior-posterior cervical surgery from 2008-2013. Nine patients (1.02%) required emergent reintubation. The interval between extubation to reintubation was 6.2 h [1-12]. Patients were kept intubated after reintubation for 2.3 d [2-3]. Seven patients displayed moderate postoperative edema. One patient was diagnosed with a compressive hematoma which was subsequently evacuated in the OR. Another patient was diagnosed with a pulmonary effusion and treated with diuretics. One patient received a late debridement for an infected hematoma. Six patients reported residual symptoms and three patients made a complete recovery. CONCLUSION Respiratory compromise is a rare but potentially life threatening complication following cervical surgery. Patients at increased risk should be monitored closely for extended periods of time post-operatively. If the airway is restored adequately in a timely manner through emergent re-intubation, the outcome of the patients is generally favorable.

Lateral Lumbar Interbody Fusion—Outcomes and Complications

Purpose of ReviewLateral lumbar interbody fusion (LLIF) is a relatively new, minimally invasive technique for interbody fusion. The goal of this review is to provide a general overview of LLIF with a special focus on outcomes and complications.Recent FindingsSince the first description of the technique in 2006, the indications for LLIF have expanded and the rate of LLIF procedures performed in the USA has increased. LLIF has several theoretical advantages compared to other approaches including the preservation of the anterior and posterior annular/ligamentous structures, insertion of wide cages resting on the dense apophyseal ring bilaterally, and augmentation of disc height with indirect decompression of neural elements. Favorable long-term outcomes and a reduced risk of visceral/vascular injuries, incidental dural tears, and perioperative infections have been reported. However, approach-related complications such as motor and sensory deficits remain a concern.SummaryIn well-indicated patients, LLIF can be a safe procedure used for a variety of indications.

Regional Bone Mineral Density Differences measured by QCT: Does the Standard Clinically Used L1-L2 Average Correlate with the Entire Lumbosacral Spine?

BACKGROUND CONTEXT Quantitative computed tomography (QCT) of the lumbar spine is used as an alternative to dual-energy X-ray absorptiometry in assessing bone mineral density (BMD). The average BMD of L1-L2 is the standard reportable metric used for diagnostic purposes according to current recommendations. The density of L1 and L2 has also been proposed as a reference value for the remaining lumbosacral vertebrae and is commonly used as a surrogate marker for overall bone health. Since regional BMD differences within the spine have been proposed, it is unclear if the L1-L2 average correlates with the remainder of the lumbosacral spine. PURPOSE The aim of this study was to determine possible BMD variations throughout the lumbosacral spine in patients undergoing lumbar fusion and to assess the correlation between the clinically used L1-L2 average and the remaining lumbosacral vertebral levels. STUDY DESIGN/SETTING This is a retrospective case series. PATIENT SAMPLE Patients undergoing posterior lumbar spinal fusion from 2014 to 2017 at a single, academic institution with available preoperative CT imaging were included in this study. OUTCOME MEASURES The outcome measure was BMD measured by QCT. METHODS Standard QCT measurements at the L1 and L2 vertebra and additional experimental measurements of L3, L4, L5, and S1 were performed. Subjects with missing preoperative lumbar spine CT imaging were excluded. The correlations between the L1-L2 average and the other vertebral bodies of the lumbosacral spine (L3, L4, L5, S1) were evaluated. RESULTS In total, 296 consecutive patients (55.4% female, mean age of 63.1 years) with available preoperative CT were included. The vertebral BMD values showed a gradual decrease from L1 to L3 and increase from L4 to S1 (L1=118.8 mg/cm3, L2=116.6 mg/cm3, L3=112.5 mg/cm3, L4=122.4 mg/cm3, L5=135.3 mg/cm3, S1=157.4 mg/cm3). There was strong correlation between the L1-L2 average and the average of the other lumbosacral vertebrae (L3-S1) with a Pearsons correlation coefficient (r=0.85). We also analyzed the correlation between the L1-L2 average and each individual lumbosacral vertebra. Similar relationships were observed (r value, 0.67-0.87), with the strongest correlation between the L1-L2 average and L3 (r=0.87). CONCLUSIONS Our data demonstrate regional BMD differences throughout the lumbosacral spine. Nevertheless, there is high correlation between the clinically used L1-L2 average and the BMD values in the other lumbosacral vertebrae. We, therefore, conclude the standard clinically used L1-L2 BMD average is a useful bone quantity measure of the entire lumbosacral spine in patients undergoing lumbar spinal fusion.

C2 Bone Erosion Secondary to Iatrogenic Pseudomeningocele: A Case Report and Description of a Novel Surgical Technique

BACKGROUND Pseudomeningoceles are a rare cause of bone erosions. Development of such erosions in the C2 vertebral body and the odontoid process can lead to life-threatening instability. Treatment options to regain stability include atlantoaxial and occipitocervical fusion. For patients with a history of Chiari decompression and large C2 lesions, common fusion techniques are not always feasible. In addition, fusion surgery sacrifices physiologic motion and is therefore a disabling procedure, especially for young and active patients. CASE DESCRIPTION We report a novel combined open operative and subsequent minimal invasive filling technique of several instable osteolytic/cystic areas within the C2 vertebra of a 28-year-old woman. The underlying cause for the lesions was a pseudomeningocele communicating with the vertebral body. This was an incidental finding 15 years after foramen magnum decompression with C1 and partial C2 laminectomy for Chiari malformation. Novel treatment included open posterior surgery with total laminectomy of the remaining C2 arch and refilling the odontoid with viscous beta tricalcium phosphate and polymethylmethacrylate bone cement. Postoperative 6- and 12-month follow-up computed tomography imaging showed a stable incorporation of the filling. CONCLUSIONS Life-threatening fractures at the occipitocervical junction are rare and often are due to high-impact trauma. Osteolytic changes at those bone compartments are a potential cause for pathologic fractures during normal daily activities. In this case, increased pressure on the bone due to a pseudomeningocele resulted in slow bone loss without symptoms. A novel combined technique of bone filling was applied successfully to stabilize the C2 vertebral bone.