WHAT’S NEW IN NEUROSURGERY?

Classical neurosurgery involved fairly large incisions, displacement and/or destruction of delicate tissues and some attendant adverse effects. For the past thirty+ years, neurosurgery—like other surgical disciplines has been striving to achieve minimization—smaller incisions, less invasive approaches, stimulation rather than removal of tissue, more use of magnified vision, imaging techniques such as MRI, and neurofunctional adjuncts such as interoperative EEG. In this blog, the author will attempt to acquaint readers with the new—and sometimes radically new—procedures. The descriptions will contain necessary sophisticated language for which there is little simple substitute. None of the descriptions will be in-depth or even approaching completeness due to lack of space. The disease processes and operative techniques will not be described at any length for the same reasons.

Great strides have been made in the treatment of previously intractable movement disorders. Decades of research and experience has resulted in the ability to place small electrodes in areas of a patient’s brain that control bodily movement. The electrodes are then attached to a sophisticated and long-lived battery buried under the skin, much like cardiac pacemakers. The implanted device sends electrical signals to the brain sites where the tips of the electrodes reside. With some trial-and-error experimentation, a frequency is established that provides optimal regulation of involuntary motor movement in patients such as those with Parkinson’s Disease, dystonia, essential tremor and sometimes in seizure disorders. The procedure is safe, effective, and almost painless. Determination of the exact point where the electrodes are to be placed is determined by MRI imaging, monitoring prolonged EEG studies, and intraoperative trials in awake patients to access whether or not stimulation of particular brain area ameliorates the abnormal movements or electrical activity. DBS is considered to be better than ablation (destruction of brain tissue) for Parkinson’s patients especially because it is adjustable and reversible.

Recently, neurologists and neurosurgeons from Cedar-Sinai reported work in the distinguished journal, Neurosurgery describing their treatment of a severely disabling form of hereditary dystonia (a condition in which there are debilitating uncontrolled abnormal involuntary movements) which is prevalent among Jews. The condition is caused by a mutation in the DYT1 gene. Deep brain stimulation (DBS) was performed and the patients followed for up to ten years. Symptom severity dropped by 80% in most patients in less than two years post-op. The majority of patients were able to discontinue all of their disease related drugs, and 90+% were able at least to discontinue one class of drugs. The beneficial effects were long lasting.

Motor improvement scores improved 60% in a group of patients Germany with DBS. Most of those patients were refractory to drugs. Adverse effects were minimal. An especially interesting new use for DBS has been found by neurosurgeons at the Allegheny General Hospital in Pennsylvania—an effective treatment for morbid obesity. DBS in the lateral hypothalamic area of the brain caused an increase in metabolism of nutrients. Although the treatment is very new, the weight loss achieved in the patients is promising, especially since the procedure is far less invasive and difficult to tolerate than bariatric surgery which is also effective but involves major g-I tract surgery with all of its discomforts and adverse effects.

Electrodes have been implanted in the brain, on the spinal cord, and on peripheral nerves to control severe, intractable, otherwise uncontrollable pain for 40 years. Recently, surgeons doing the implantation surgery have joined in a cooperative to study the evidence-based results of the several types of neuromodulators currently in use.  Of particular interest because of the high incidence in the population is DBS for control of chronic migraine. Neuromodulator technics have resulted in a 28% reduction in migraine frequency and 40+% reduction in severity of the headaches. Over half of the treated patients reported good to excellent relief. Spinal cord stimulator emplacement procedures have improved from large open operations to placement of a wire and electrode pad via a needle—much like the epidural anesthetic procedures for delivery. Nerve stimulators for occipital neuralgia—a fairly common cause of debilitating headache—are showing promising results. Surgical transection of the large nerves situated on the back of the head also have shown to be effective, but do require an open invasive approach.

Very recently DBS has been employed in the field of psychiatric neurosurgery. Ablative techniques have been around since the 1940s and are effective but carry the same risks as all open surgery and are associated with some risk of brain dysfunction post-operatively. The ablative procedures, like electroconvulsive shock therapy for depression, have fallen into unpopularity, in part because of political-correctness: advocates for the mentally ill decry the procedures as invasions of privacy and as being imposed on people who cannot make rational choices. In 2009, the US FDA granted approval for some DBS procedures for intractable obsessive-compulsive disorder (OCD) conditions. The FDA also approved a few refined ablative lesion procedures. Better understanding of neurocircuitry anatomy and pathology is affording a more rational approach to the crying need for such treatment.

Transcranial (across the head) MRI guided focused ultrasound surgery appears to hold promise as a relatively non-invasive treatment for such disorders as essential tremors, neuropathic pain, and Parkinson’s Disease. The same disruptive technology is in use for the treatment of uterine fibroids, painful metastatic cancer in bones, and breast tumors. For neurosurgical purposes, the technology carries less risk than open surgery, targeted ablative surgery, radio surgery, and DBS.

Use of MRI guided technology has been immensely helpful in accomplishing successful and minimal neurosurgical approaches, especially in ablative surgery which will be discussed in the next blog.