History of Spine Surgery

Published on 02/04/2015 by admin

Last modified 02/04/2015

Print this page

This article have been viewed 4263 times

Chapter 1 History of Spine Surgery

The evolution of spinal surgery has revolved around three basic surgical goals: decompression, surgical stabilization, and deformity correction. To emphasize their importance, these surgical goals form the framework for this chapter. However, other related fundamental arenas, such as anatomy, biomechanics, nonsurgical treatment modalities, contributed to the development of surgical concepts as well.

Although the main advances in spine surgery occurred in the 19th and 20th centuries, their roots date back several thousand years. Without understanding and appreciating the past, it is not possible to understand and appreciate the advancements of the last two centuries. Therefore, before touching upon the last two centuries’ history of the spine, a short examination of spine medicine from the antique period, medieval period, and Renaissance is presented.

Antique Period and Spine Surgery

There is no evidence of surgical decompression and stabilization, or the surgical correction of deformity, during the antique period except for laminectomy in a trauma case reported by Paulus of Aegina. However, it is known that physicians of the antique period were, to some extent, able to evaluate patients with spinal disorders. They in fact used frames for reduction of dislocation and gibbus and applied some of the knowledge gained from human and animal dissections.

Srimad Bhagwat Mahapuranam, an ancient Indian epic (3500–1800 bce), depicts the oldest documentation of spinal traction. In a passage from this document, it is described that Lord Krishna applied axial traction to correct a hunchback in one of his devotees.¹

The Edwin Smith Papyrus (2600–2200 bce) is the most well-known document on Egyptian medicine. This document reports 48 cases. Imhotep (2686–2613 bce), a late second-dynasty surgeon, authored this papyrus, which reported six cases of spinal trauma. Hence, nearly 4600 years ago, vertebral subluxation and dislocation and traumatic quadriplegia and paraplegia were described.² Recently, it was reported that Egyptian physicians described the “spinal djet column concept.”³

Antique medicine was also influenced by the Greco-Roman period physicians.⁴ Hippocrates (460–375 bce) addressed the anatomy and pathology of the spine, describing the normal curvatures of the spine, its structure, and the tendons attached to it. He defined tuberculous spondylitis, posttraumatic kyphosis, scoliosis, spinal dislocation, and spinous process fracture. He addressed the relationship between spinal tuberculosis and gibbus. According to Hippocrates, spinous process fracture was not dangerous. However, fractures of the vertebral body were more important. He described two frames for reduction of the dislocated spine, including the Hippocratic ladder and the Hippocratic board.⁵ The details of Hippocratic treatment were recorded by Aulus Cornelius Celsus (25 bce–50 ce).

Aristotle (384–322 bce) focused on kinesiology. His treatises—“parts of animals, movement of animals, and progression of animals—described the actions of the muscles.” He analyzed and described walking, in which rotatory motion is transformed into translational motion. Although his studies were not directly related to the spine, they were the first to address human kinesiology and, in fact, biomechanics.⁶

Galen of Pergamon (130–200 ce), another physician of the antique era, worked as a surgeon and anatomist. He studied the anatomy of animals and extrapolated his findings to human anatomy. His anatomic doctrines became the basis for medical education for more than 1200 years. He used the terms kyphosis, scoliosis, and lordosis, and he attempted to correct these deformities. He also worked as the official surgeon of gladiators in amphitheaters. Because of this position, he was accepted as “the father of sports medicine.” He confirmed the observations of Imhotep and Hippocrates regarding the neurologic sequences of cervical spine trauma. Nevertheless, to the best of our knowledge, he did not operate for spinal trauma.^6,⁷

Oribasius (325–400 ce), another physician of the antique period, added a bar to the Hippocratic reduction device and used it to treat both spinal trauma and spinal deformity.⁸

One of the most important figures dealing with spinal disorders during the end of this period was Paulus of Aegina (625–690 ce). He collected what was known from the previous 1000 years in a seven-volume encyclopedia. Paulus of Aegina not only used the Hippocratic bed, but also worked with a red-hot iron. He is credited with performing the first known laminectomy. This was performed for a case of spinal fracture resulting in spinal cord compression. He emphasized the use of orthoses in spinal trauma cases.^6,⁹

Medieval Period and Spine Surgery

The studies and reports of Paulus of Aegina are the most important source of information regarding this period of medicine. This age was followed by the Dark Ages (ca. 500–1000 ce) in Europe. Although Western medicine showed no progress during the Dark Ages, the Eastern world developed the science. The early Islamic civilizations realized the importance of science and scientific investigation. The most important books of the antique age were translated into Syrian, Arabic, and Persian. Therefore, using the Western doctrines, the Islamic civilizations discovered new information and were able to contribute further. In terms of spine medicine, several important contributors, including Avicenna and Abulcasis, added to this movement.

Avicenna (981–1037 ce), a famous physician from present-day Uzbekistan, worked in all areas of medicine (Fig. 1-1). His famous book, the Canon of Medicine, was a seminal textbook until the 17th century in Europe. He described the biomechanics-related anatomy of the spine, as well as flexion, extension, lateral bending, and axial rotation of the spine.¹⁰ Avicenna also used a traction system similar to the system described by Hippocrates.

FIGURE 1-1 Avicenna.

Abulcasis (936–1013 ce), a famous Arabian surgeon of the 11th century, wrote a surgery treatise, “At-Tasnif.” He described several surgical disorders, including low back pain, sciatica, scoliosis, and spinal trauma. He recommended the use of chemical or thermal cauterization for several spinal disorders. He also developed a device to reduce the dislocated spine.¹¹

Serefeddin Sabuncuoglu (1385–1468 ce), a Turkish physician of the 15th century, wrote an illustrated atlas of surgery,¹² in which he described scoliosis, sciatica, low back pain, and spinal dislocations. He delineated a technique for reduction of spinal dislocations, using a frame similar to that designed by Abulcasis.

Renaissance and Spine Surgery

Gradually, the intellectual doldrums of the Dark Ages in Europe evolved into the Renaissance. Academic centers were established in Europe, as well as centers for the translation of documents, similar to centers established in Islamic regions. Thus, the classics from the antique age were translated into Latin from Arabic, making their scientific information available to the scholars and physicians of the Renaissance. During this time, the Western world spawned disciplines, including art, medicine, physics, and mathematics.

The works of Leonardo Da Vinci (1452–1519 ce) are of importance in this regard. Da Vinci worked on the philosophy of mechanics and on anatomy in De Figura Humana. He described spine anatomy, the number of vertebrae, and the joints in detail. By studying anatomy in the context of mechanics, da Vinci gained some insight into biomechanics. He considered the importance of the muscles for stability in the cervical spine. However, his work was unpublished for centuries, and his brilliant daydreaming had a limited scientific influence on biomechanics.^13,¹⁴

Andreas Vesalius (1514–1564 ce), an anatomist and physician, wrote his famous anatomy book, De Humani Corporis Fabrica Liberi Septum, which changed several doctrines described by Galen. Actually, it took several centuries for the world to accept that Galen had made errors that were corrected by Vesalius. Because he described and defined modern anatomy, he is commonly accepted as the father of anatomy. He described the spine, intervertebral disc, and intervertebral foramina. His biomechanical point of view regarding the flexion extension of the head was similar to that of Avicenna.¹⁵

The early anatomic studies and observations were followed by biomechanical advancements. Prominent among the contributors to those advancements was Giovanni Alfonso Borelli (1608–1679 ce), who described the biomechanical aspects of living tissue. He is the founder of the “iatrophysics” concept—a term that subsequently became known as biomechanics. He is accepted as the “father of spinal biomechanics.” His book, De Motu Animalium, describes the movements of animals. He wrote that the intervertebral disc is a viscoelastic material that carries loads. This is so because he observed that muscles could not bear the loads alone. He concluded that the intervertebral discs should have function during load bearing. He was the first scientist to describe the human weight center (center of gravity).^16,¹⁷

The studies and accomplishments of the Renaissance period were not limited to the aforementioned. Many scientists contributed to the body of the literature in this period. The advancements from this period resulted in the formation of early modern surgery, beginning in the 19th century.

Early Modern Period and Spine Surgery

Spinal Decompression and the Early Modern Period

Although an open decompression of the spinal canal for spinal cord compression was recommended by some surgeons as early as the 16th and 18th centuries (e.g., Pare, Hildanus), there is no evidence of successful intervention except for a case reported by Paulus of Aegina prior to the 19th century.

Spinal decompression in the early modern period was primarily via laminectomy. Throughout most of the 19th century, laminectomy was developed and its utility debated as the only surgical approach to all spinal pathologies, including tumor, trauma, and infection. At the dawn of the 20th century, the indications for laminectomy were extended to the decompression of spinal degenerative disease, an understanding of which had eluded 19th-century surgeons because they failed to appreciate the connection between its clinical and pathologic manifestations.

During the 19th century, spinal surgery was performed almost exclusively for neural element decompression. Numerous nonoperative approaches to deformity correction were attempted over the centuries, but the surgical approach to deformity correction was a 20th-century development. The techniques of spinal stabilization were also a product of the 20th century—both spinal fusion and internal fixation appearing around the turn of the 20th century. Moreover, a failure to recognize the implications for treatment of degenerative spinal disease, including spondylosis and degenerative disc disease, meant that the solution to these problems had to wait for the new century.

Thus, during the 19th century, the indications for spinal surgery were limited to the treatment of tumor, trauma, and infection.¹⁸ Although each of these conditions posed unique clinical and surgical problems, they shared the need for surgical decompression. Throughout the early modern period, surgical decompression of the spine was the single most common reason to undertake the risks of spinal surgery, and laminectomy was the most commonly used technique to achieve it.

Birth and Development of the Laminectomy

H. J. Cline, Jr., and the Argument against Spinal Surgery

At the beginning of the 19th century, the prospects for spinal surgery appeared grim. The dismal results of a well-publicized operation for a traumatic spinal injury stimulated a heated debate over the “possibility” of spinal surgery that persisted for nearly a century. At the center of this debate was H. J. Cline, Jr., a little-known British surgeon.

In 1814, Cline performed a multilevel laminectomy for a thoracic fracture-dislocation associated with signs of a complete paraplegia (Fig. 1-2).¹⁹ The patient was a 26-year-old man who fell from the top of a house. “He was bled previous to his admission” to the St. Thomas’s Hospital in London, “and some imprudent attempts were made to relieve him by pressing the knees against the injured part, which only increased the pain and inflammation.”¹⁹ Upon admission to the hospital the patient was examined by Cline, who “ascertained that some of the spinous processes . . . were broken off and were pressing upon the spinal marrow . . . [and] who resolved to cut down and remove the pressure from the spinal marrow.”¹⁹

FIGURE 1-2 First page of H. J. Cline Jr.’s historic laminectomy, as reported by G. Hayward.

(From Cline HJ Jr [cited by Hayward G]: An account of a case of fracture and dislocation of the spine. N Engl J Med Surg 4:13, 1815.)

The patient was observed overnight in the hospital, and on the day following admission, Cline performed his proposed operation. Although the operation was performed within 24 hours of injury, Cline was unable to reduce the dislocation or to achieve a complete decompression of the neural elements. The patient survived for 3 days after surgery, with increasing pain and a steadily increasing pulse. On postoperative day 4, however, the patient died, “and on an examination of the body by Mr. Cline, it was found that the spinal marrow was entirely divided.”¹⁹ Despite the severity of the neural injury, and the complexity of the fracture-dislocation, the untoward outcome of this unfortunate case would remain a topic of conversation for almost a century, providing ample ammunition for the opponents of spinal surgery.

Of course, the case of Cline was not an isolated mortality. In 1827, for example, Tyrell ²⁰ reported a 100% mortality for a small series of patients with surgically treated spinal dislocation and neurologic injury. Other reports (e.g., Rogers²¹ in 1835) were often equally discouraging. Looking back on these early years of the debate about spinal surgery, the early 20th century British surgeon Donald Armour²² described the controversy this way:

This [Cline’s operation] precipitated and gave rise to widespread and vehement discussion as to its justification. This discussion, often degenerating into bitter and virulent personalities, went on many years. Astley Cooper, Benjamin Bell, Tyrell, South, and others favored it, while Charles Bell, John Bell, Benjamin Brodie, and others opposed it. The effect of so eminent a neurologist as Sir Charles Bell against the procedure retarded spinal surgery many years—the operation was described with such extravagant terms as “formidable,” “well-nigh impossible,” “appalling.” “desparate [sic] and blind,” “unjustifiable,” and “bloody and dangerous.”

Of course, surgical fatalities in this period were due as much to septic complications and anesthetic inadequacies as they were to surgical technique. The lack of an effective means of pain control during surgery intensified the problem of intraoperative shock and made speed essential. Furthermore, the problems of wound infection and septicemia were both predictable and frequently fatal. These hindrances to surgery were not ameliorated until the introduction of general anesthetic agents (i.e., nitrous oxide, ether, and chloroform) in the mid-1840s and the adoption of Listerian techniques (using carbolic acid) in the 1870s.²³

A. G. Smith and the First Successful Laminectomy

Despite these risks, a little-known surgeon named Alban G. Smith from Danville, Kentucky, performed a laminectomy in 1828 on a patient who had fallen from a horse and sustained a traumatic paraplegia. To Smith’s credit, his patient not only survived the operation but achieved a partial neurologic recovery. The operative technique and surgical results were reported in the North American Journal of Medicine and Surgery in 1829 (Fig. 1-3).²⁴ Smith’s procedure comprised a multilevel laminectomy through a midline incision, involving removal of the depressed laminae and spinous processes, exploration of the dura mater, and closure of the soft tissue incision. Although the report of this landmark case appears to have attracted little attention at the time, it is a significant technical achievement and places Smith among the pioneers of the early modern period in spinal surgery.

FIGURE 1-3 Title page of journal that contains the first successful report of a laminectomy. The surgeon, and the author of the report, was Alban G. Smith of Danville, Kentucky.

(From Smith AG: Account of a case in which portions of three dorsal vertebrae were removed for the relief of paralysis from fracture, with partial success. North Am Med Surg J 8:94–97, 1829.)

Laminectomy for Extramedullary Spinal Tumor

During the half century after Smith’s historic operation, the primary indication for laminectomy was spinal trauma. In the latter part of the 19th century, the indications for laminectomy were extended to tumor and infection.²⁵ The first and most celebrated surgical case for spinal tumor in the 19th century, that of Captain Gilbey, was also the first successful one, and it played an important role in the rehabilitation of the laminectomy as a safe and effective procedure.

Captain Gilbey was an English army officer who suffered the misfortune of losing his wife in a carriage accident in which he also was involved. Although Gilbey himself escaped serious injury, he soon began to experience progressive dull back pain, which he attributed to the accident. As the pain became relentless, Gilbey sought the advice of a series of physicians, all of whom were unable to identify the source of his pain. Eventually, Gilbey was referred to the eminent London neurologist, William Gowers, who elicited from the patient a history of back pain, urinary retention, paraplegia, and loss of sensation below the thoracic level (Fig. 1-4).²⁶

FIGURE 1-4 William R. Gowers.

The neurologist’s diagnosis was immediate and unequivocal: the cause of Gilbey’s symptoms was located in his spine, where a tumor was causing compression of the thoracic spinal cord. Although no intraspinal tumor had ever been resected successfully, Gowers referred the patient to his London surgical colleague, Victor Horsley (Fig. 1-5). After all, Gowers had himself asserted, in his authoritative textbook, Manual of Diseases of the Nervous System, that removal of an intradural spinal cord tumor was “not only practicable, but actually a less formidable operation than the removal of intracranial tumors.”²⁷

FIGURE 1-5 Sir Victor Horsley.

Horsley acted quickly. Within 2 hours of the initial consultation, a skin incision was made at 1 pm, June 9, 1887, at the National Hospital, Queens Square, London. Despite his precipitous decision to undertake this dangerous operation, Horsley did not approach the operation unprepared. Although the Act of 1876 made it a criminal offense to experiment on a vertebrate animal for the purpose of attaining manual skill, Horsley had repeatedly practiced the proposed procedure in the course of his surgical experimentation. Despite some initial difficulty in locating the tumor, an intradural neoplasm in the upper thoracic spine causing compression of the spinal cord was identified and safely resected. The pathologic diagnosis was “fibromyxoma of the theca.”

Follow-up 1 year later revealed almost complete neurologic recovery. The patient was walking without assistance and had returned to his premorbid work schedule. He remained well, with no evidence of tumor recurrence, up to the time of his death from an unrelated cause 20 years later.

Laminectomy for Intramedullary Spinal Tumor

In 1890, Fenger attempted to remove an intramedullary spinal tumor in an operation that resulted in the patient’s death.²⁸ In 1905, Cushing^29,³⁰ also attempted to remove an intramedullary spinal cord tumor but decided to abort the procedure after performing a myelotomy in the dorsal column. To Cushing’s surprise, the patient improved after surgery. In 1907, von Eiselsberg³¹ successfully resected an intramedullary tumor.

The unexpected improvement that was observed in the patient reported by Cushing attracted the attention of the New York surgeon Charles Elsberg. Elsberg ³² described Cushing’s technique, which he aptly named the “method of extrusion.” The technique was intended to remove an intramedullary tumor by spontaneous extrusion of the tumor through a myelotomy made in the dorsal column. The rationale for this method was predicated on the theory that an intramedullary tumor was associated with an increase in intramedullary pressure. Release of this pressure by a myelotomy that extended from the surface of the spinal cord to the substance of the tumor was expected to provide sufficient force to spontaneously extrude the tumor. According to Elsberg, the advantage of this procedure over a standard tumor resection was that it required minimal manipulation of the spinal cord and therefore minimal spinal cord tissue injury.

Because the spontaneous extrusion of an intramedullary tumor occurred slowly, Elsberg performed these procedures in two stages. In the first stage, a myelotomy was fashioned in the dorsal column, extending from the surface of the spinal cord to the tumor (Fig. 1-6A).

FIGURE 1-6 A, The first stage in an intramedullary spinal cord tumor resection by the extrusion method. Note that the tumor is bulging through the myelotomy incision. The wound was subsequently closed. B, The second stage in an intramedullary spinal cord tumor resection by the extrusion method, 1 week after the first stage. Note that the tumor has spontaneously extruded since the first operation, and now may be removed easily.

(From Elsberg CA, Beer E: The operability of intramedullary tumors of the spinal cord. A report of two operations with remarks upon the extrusion of intraspinal tumors. Am J Med Sci 142:636–647, 1911.)

When the tumor was identified and observed to begin to bulge through the myelotomy incision, the operation was concluded, the dura mater was left opened, and the wound closed. In the second stage of the procedure, which was performed approximately 1 week after the first stage, Elsberg reopened the wound and inspected the tumor (Fig. 1-6B). Typically, the tumor was found outside the spinal cord, and the few adhesions that remained between the spinal cord and the tumor were sharply divided. After the tumor was removed, the wound, including the dura mater, was closed.

Variations in Laminectomy Technique

By the last decade of the 19th century, after the case of Captain Gilbey, the possibility of safely performing a spinal operation was established in the collective surgical consciousness. Furthermore, new anesthetic techniques and aseptic methods had become available to most practicing surgeons.³³ All of these factors served to increase the appeal of the laminectomy to surgeons and to widen its range of application. For example, after Horsley’s widely publicized success for resecting a spinal tumor, many similar operations were soon described in the literature,³⁴^–³⁹ and in 1896, Makins and Abbott⁴⁰ reported 24 cases of laminectomy for vertebral osteomyelitis.

Although the safety and efficacy of the laminectomy had convinced many proponents of the utility of the procedure, toward the end of the century surgeons began to worry about postoperative instability. Advances in operative technique and perioperative management meant that more and more patients survived the operation and ultimately became ambulatory, which further heightened concern about stability.

In 1889, Dawbarn ⁴¹ described an osteoplastic method of laminectomy that addressed this concern. Instead of a midline incision, Dawbarn described two lateral incisions that were carried down to the transverse processes. The lateral incisions were connected in an H-like fashion, and a superior and inferior flap—including skin, muscle, fascia, and bone—was then turned. In closing the wound, the intact flaps were reflected back and reapproximated in their normal anatomic positions.

Although not all surgeons subscribed to the osteoplastic method, many turn-of-the-century surgeons were largely preoccupied with modifications of this procedure.⁴² At the same time, however, a more important innovation in laminectomy technique, the hemilaminectomy, was developed independently in both Italy^43,⁴⁴ and the United States.⁴⁴

In 1910, A. S. Taylor of New York described the hemilaminectomy: a midline incision, a subperiosteal paravertebral muscle takedown, and the removal of a hemilamina with a Doyen saw. The advantages of the hemilaminectomy over the cumbersome osteoplastic method were obvious, and Taylor argued that compared with the laminectomy, the hemilaminectomy interfered less with the mechanics of the spine. Despite such detractors as Charles Elsberg, who responded that the field of view was narrow and the effect of laminectomy on spinal mechanics negligible, Taylor successfully championed its use.

Charles A. Elsberg: The Laminectomy in Stride

Charles A. Elsberg was one of the most influential writers on spinal decompression (Fig. 1-7). Working at the Neurological Institute of New York, which he had helped to found, Elsberg⁴⁵ published his first series of laminectomies in 1913. In 1916, he published his classic text, Diagnosis and Treatment of Surgical Diseases of the Spinal Cord and Its Membranes.⁴⁶ Although these publications represent landmarks in the history of spinal surgery, they constitute more of a culmination than an innovation in spinal surgery. Elsberg’s work on spinal surgery, coming as it did at the end of a century of evolution of the decompressive laminectomy, effectively codified 19th and early 20th century developments.

FIGURE 1-7 Charles A. Elsberg.

In his textbook, Elsberg outlined the surgical indications and contraindications for laminectomy. He noted the beneficial effects in his own large series of laminectomies and puzzled over the benefits that may occur in the absence of evident increased intradural pressure, such as in patients with multiple sclerosis. He argued that the primary indications for operation were cases of tumor, trauma, and infection that were associated with symptoms localized to a spinal level. Patients with progressive symptoms should be operated on quickly, in the absence of contraindications such as metastatic cancer or advanced Pott’s disease.

Given the exhaustive scope of these early Elsberg publications—which, in addition to tumor, trauma, and infection, also review the management of congenital spine disease—conspicuously little is said about the most common late 20th-century indication for laminectomy: degenerative spine disease. The tardy development of a treatment for degenerative spine disease should be understood in the larger context of 19th and early 20th century knowledge of spinal pathology.

Unlike degenerative disease, tumor, trauma, and infection were already well-known in antiquity. Although the concept of localization of function in the nervous system was undeveloped during the 19th century, the diagnosis and localization of tumor, trauma, and infection, particularly in their late stages, was not especially difficult. Degenerative disease, on the other hand, possessed a more subtle pathophysiology that was not as easily characterized, especially without the help of radiography. Thus, recognition of degenerative spine disease eluded the 19th-century surgeon. This tardy appreciation for the clinical, surgical, and pathologic importance of degenerative spine disease deserves further mention.

Laminectomy for Intervertebral Disc Herniation

Intervertebral disc pathology was first described by Rudolph Virchow ⁴⁷ in 1857 (Fig. 1-8). Virchow’s description of a fractured disc was made at autopsy on a patient who had suffered a traumatic injury.

FIGURE 1-8 Rudolph Virchow.

In 1896, the Swiss surgeon T. Kocher ^48,⁴⁹ identified and described a traumatic disc rupture at autopsy of a patient who had fallen 100 feet and landed on her feet. Although Kocher recognized that the L1-2 disc was displaced dorsally, no clinical correlation was suggested.

The first transdural intervertebral discectomy was reported by Oppenheim and Krause ⁵⁰ in 1908. However, they reported the disc as “enchondroma.”

In 1911, George Middleton,⁵¹ a practicing physician, and John Teacher, a Glasgow University pathologist, described two cases of ruptured intervertebral disc observed at autopsy. Like Virchow and Kocher before them, however, Middleton and Teacher, although they described the pathology, failed to postulate its connection with radiculopathy or back pain.

In 1911, Joel Goldthwaite ⁵² made this connection. In an article on the lumbosacral articulation, Goldthwaite described and illustrated how weakening of the annulus fibrosus could result in dorsal displacement of the nucleus pulposus. The nucleus pulposus, he argued, could in turn result in low back pain and paraparesis. What eluded Goldthwaite and the surgeons before him, however, was the connection between a herniated disc and radiculopathy.

In a 1929 issue of the Archives of Surgery, Walter E. Dandy ⁵³ published a description of two cases of herniated lumbar discs causing a cauda equina syndrome (Fig. 1-9). Dandy correctly described how “loose cartilage from the intervertebral disc” produced the symptoms of cauda equina compression that were relieved alter surgical decompression. He considered that in the second decade of the 20th century, more than 20 years after the first spinal fusion operations, intervertebral disc disease could be added to the list of indications for decompressive laminectomy.

FIGURE 1-9 Walter E. Dandy.

Despite the several aforementioned publications on intervertebral disc herniation, the concept of disc herniation and its relationship to radiculopathy was defined by Mixter and Barr.

Several studies were performed in North America, but an anatomic, radiologic, and microscopic study was performed on 5000 human spines in the Dresden Pathology Institute by Schmorl and Junghanns. The results of this study were published in a book entitled The Human Spine in Health and Disease. In 1932, Barr, an orthopedic surgeon from Massachusetts General Hospital, was assigned to write a critique of this study.

In June of 1932, Barr attempted to treat a patient with an extruded disc herniation. Following a 2-week unsuccessful course of nonoperational treatment, Barr consulted with Mixter. Mixter recommended a myelogram. The myelogram revealed a filling defect. Mixter subsequently operated on the patient and removed the “tumor.” Barr studied the “tumor” specimens. Because he contributed to Schmorl’s study published in German, Barr remembered the microscopic appearances in Schmorl’s study and realized that the specimen from this index patient was the nucleus pulposus. After this finding, Mixter, Barr, and Mallory (pathologist) reevaluated all the cases that were diagnosed (or misdiagnosed) as chondroma in recent years at Massachusetts General Hospital. They retrospectively diagnosed most of these cases as ruptured intervertebral discs. Mixter and Wilson operated on the first ruptured disc herniation diagnosed preoperatively on December 31, 1932. Mixter and Barr reported the case in New England Surgical Society in September 30, 1933.^8,^54,⁵⁵

In the late 1930s Love ⁵⁶ from the Mayo Clinic reported on an extradural laminectomy technique. In 1967, Yasargil⁵⁷ used the microscope for discectomy. The first results of the lumbar microdiscectomy were reported by Yasargil⁵⁷ and Caspar.⁵⁸

Laminectomy for Cervical Disc Herniation

In 1905 Watson and Paul ⁵⁹ performed a negative exploration for cervical spinal cord tumor. They found an anterior extradural mass in the intervertebral disc at autopsy. This may be the first reported case of cervical disc herniation. The first dorsal approach was performed by Elsberg⁶⁰ in 1925. He found a “chondroma” in a quadriparetic patient.