Stereotactic surgery is a minimally invasive form of surgical intervention that makes use of a three-dimensional coordinate system to locate small targets inside the body and to perform on them some action such as ablation, biopsy, lesion, injection, stimulation, implantation, radiosurgery (SRS), etc.

However, difficulties in setting up a reliable frame of reference (such as bone landmarks, which bear a constant spatial relation to soft tissues) mean that its applications have been, traditionally and until recently, limited to brain surgery.

The stereotactic atlas is a series of cross sections of anatomical structure (for example, a human brain), depicted in reference to a two-coordinate frame.

The mechanical device has head-holding clamps and bars which puts the head in a fixed position in reference to the coordinate system (the so-called zero or origin).

[3] Guide bars in the x, y and z directions (or alternatively, in the polar coordinate holder), fitted with high precision vernier scales allow the neurosurgeon to position the point of a probe (an electrode, a cannula, etc.)

Currently, a number of manufacturers produce stereotactic devices fitted for neurosurgery in humans, for both brain and spine procedures, as well as for animal experimentation.

Stereotactic radiosurgery utilizes externally generated ionizing radiation to inactivate or eradicate defined targets in the head or spine without the need to make an incision.

[5] This concept requires steep dose gradients to reduce injury to adjacent normal tissue while maintaining treatment efficacy in the target.

[14] Stereotactic radiosurgery provides an efficient, safe, and minimal invasive treatment alternative[15] for patients diagnosed with malignant, benign and functional indications in the brain and spine, including but not limited to both primary and secondary tumors.

[16] Stereotactic radiosurgery is a well-described management option for most metastases, meningiomas, schwannomas, pituitary adenomas, arteriovenous malformations, and trigeminal neuralgia, among others.

[17] Irrespective of the similarities between the concepts of stereotactic radiosurgery and fractionated radiotherapy and although both treatment modalities are reported to have identical outcomes for certain indications,[18] the intent of both approaches is fundamentally different.

[5] Historically, the field of fractionated radiotherapy evolved from the original concept of stereotactic radiosurgery following discovery of the principles of radiobiology: repair, reassortment, repopulation, and reoxygenation.

[18] A second, more recent evolution extrapolates the original concept of stereotactic radiosurgery to extra-cranial targets, most notably in the lung, liver, pancreas, and prostate.

[22] To monitor and correct target motion for accurate and precise patient positioning prior and during treatment, advanced image-guided technologies are commercially available and included in the radiosurgery programs offered by the CyberKnife and Novalis communities.

To alleviate extra pyramidal disorders, pioneer Russell Meyers dissected or transected the head of the caudate nucleus in 1939,[24] and part of the putamen and globus pallidus.

[25] More recent clinical applications can be seen[26] in surgeries used to treat Parkinson's disease, such as Pallidotomy or Thalamotomy (lesioning procedures), or Deep Brain Stimulation (DBS).

[27] During DBS, an electrode is placed into the thalamus, the pallidum of the subthalmamic nucleus, parts of brain that are involved in motor control, and are affected by Parkinson's disease.

[43] This device became almost universally adopted by the 1980s[44] and is included in the Brown-Roberts-Wells (BRW),[45] Kelly-Goerss,[46] Leksell,[47] Cosman-Roberts-Wells (CRW),[48] Micromar-ETM03B, FiMe-BlueFrame, Macom, and Adeor-Zeppelin[49] stereotactic frames and in the Gamma Knife radiosurgery system.

[citation needed] In 1970, in the city of Buenos Aires, Argentina, Aparatos Especiales company, produced the first Stereotactic System in Latin America.

[53] In rodents, the main applications of stereotactic surgery are to introduce fluids directly to the brain or to implant cannulae and microdialysis probes.

Site specific central microinjections are used when rodents do not need to be awake and behaving or when the substance to be injected has a long duration of action.