Etapas de adopción BIM y Capital Humano

DBS is regarded to be a relatively safe and effective procedure, but it is not absolutely free of risks and complications.

Stimulation induced Adverse Effects

The complexity of the surgical procedure of DBS results in causing undesired effects of stimulation due to unplanned position of the DBS lead or due to stim- ulation spreading into tissue surrounding the planned target. Naturally these effects vary based on the planned target structure. The most common adverse effect of GPi DBS is dysarthria, perhaps due to stimulation of the cortico- bulbar tract in the internal capsule.342 _{Other adverse effects of GPi DBS in-}

clude headache, nausea, muscle contractions of face and limbs, numbness and abnormal eye movements. In case of STN DBS, adverse effects caused by the stimulation of third nerve or rostral interstitial nucleus like motor contractions and dysarthria, paresthesia and oculomotor effects are observed.21, 344 _Other

effects like nausea, heat sensation and sweating are also common.239 _{Flora et}

al.60 _{performed a systematic review for a collective of 430 patients of VIM}

DBS and found adverse effects like paraesthesia (18.84%), dysarthria (8.84%) and headache (7.21%) among others. These may be a result of stimulation spreading posteriorly into the Ventro-caudal (Vc) nucleus, medially into the medial lemniscus242_{or laterally into the internal capsule.}16, 102, 344 _{These symp-}

toms are usually temporary, occurring during intraoperative stimulation tests or immediately after stimulation and wearing off with time. In case they persist afterwards, they can still be controlled by adjusting stimulation parameters. Apart from these acute adverse effects of stimulation, reports of chronic ad- verse effects affecting the cognitive and psychiatric status of the patients have also been reported. Verbal fluency has been reported to decrease after STN- DBS.111, 252, 328 _{Studies have compared cognitive function of PD patients after}

STN-DBS with GPi-DBS and have reported that STN-DBS patients showed greater decline.364 _{This decline however, is not very large and it cannot be said}

for certain if it is an adverse effect of DBS or signs of worsening disease. Mood variations have also been reported in relation to STN-DBS, Berney et al.26 _re-

porting a decline while Daniele et al.58 _{reporting an improvement. Takeshita et}

al.343 _{have reported an incidence rate of mania between 4.2% and 8.1% as well}

symptom in terms of patient management as it relates to suicide risks. Reported incidence rate of minor depression (31.4%) are much higher compared to major depression (1.6%).99 _{History of depression and excessive tapering of levodopa}

after DBS have been reported as risk factors of depression.363, 371 _{In another}

study, Witt et al.372 _{reported that STN-DBS effects on cognitive function could}

be avoided by ensuring that the stimulating contact is in the STN and the DBS lead does not pass through the head of the caudate nucleus.

Suicide risks have been reported in relation to DBS. In a multicentre study consisting of 5311 patients, 24 (0.45%) committed suicide while 48 attempted suicide (0.90%).360 _{The researchers also identified 3 risk factors for suicide:}

i) relatively younger age, ii) early onset of PD and iii) a preoperative suicide attempt. Other studies have reported different incidence rates of suicide risks between 0 and 5%.42, 99 _{But, like adverse cognitive function, incidence rates of}

suicide are higher in PD patients than in the world population as reported by the World Health Organization.243 _{In addition, PD patients who undergo DBS}

have higher severity of the disease and usually are on their limits for treatment through medication. Thus, in absence of any studies comparing the suicide risks between advance PD patients with and without DBS, it is not possible to attribute higher suicide rates to STN-DBS alone.

Other Complications

A critical surgical complication of DBS is intracranial haemorrhage i.e. bursting of blood vessels due to insertion of DBS leads or microelectrodes. The reported incidence rate in clinical studies varies from 1 to 25%.94 _{Older patients and}

patients with high blood pressure are at a higher risk of having haemorrhage during DBS. The use of multiple MER electrodes has also been associated with higher occurrence of haemorrhages, and studies have suggested to use few MER electrodes and only when necessary.383 _{Another way to reduce chances of}

haemorrhages would be to use contrast based MRI images during the planning to identify the blood vessels and avoid them along the trajectory. Other surgical complications with lower incidence rates include confusion, anxiety and seizure as well as hypotension and arrhythmia.94

Continuous chronic stimulation may be halted due to hardware failures like cable breakage or malfunctioning IPG. Incidence rates for electro-mechanical failures including failure of IPG, electrode displacement and breakage as well as breakage of extension cords range from 4 to 9.7%.338 _{One study also reported}

2 patients having allergic reactions to DBS systems.259 _{The connection area}

between the DBS lead and the extension cord is the most frequent place for breakage.95 _{Chances of equipment failure can be reduced by avoiding wiring at}

sharp angles and not implanting the IPG in the pectoral region for patients with well-developed muscles in that region. Another hardware related adverse event is infection with incidence rates ranging from 2.9 to 7.7%338 _{with an average}

infection rate of 4.7%.29 _{Risk factors include age of the patients (younger than}

58 years or older than 65 years) among others.28 _Sugiyama338 _{suggests exten-}

sive patient management (bathing, etc), precautionary handling of DBS device (using surgical instruments) and other surgical precautions to limit chances of infection during DBS surgeries.