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Object. Because of the lack of magnetic resonance (MR) signal from cortical bones, MR imaging is inadequate for diagnosing ossified lesions in the spinal canal. However, MR imaging provides important information on spinal cord morphology and associated soft-tissue abnormality. The purpose of this study is to determine the role of MR imaging in the diagnosis and treatment of patients with ossification of the posterior longitudinal ligament (OPLL) of the cervical spine. Methods. The authors reviewed MR imaging findings in 42 patients with cervical OPLL who were examined with a superconducting MR imaging system. The types of OPLL reviewed included eight cases of continuous, 21 cases of segmental, and 13 cases of the mixed type. All patients were treated surgically either by anterior (26 cases) or posterior decompression (16 cases). Conclusions. The T1-weighted images clearly demonstrated the spinal cord deformity caused by OPLL. Associated disc protrusion was found to be present at the maximum compression level in 60% of the patients in this series. The highest incidence of disc protrusion (81%) was found in patients with segmental OPLL. Intramedullary hyperintensity on T2*-weighted imaging was noted in 18 patients (43%). The neurological deficits observed in these 18 patients were significantly more severe than those observed in the other 24 patients. Postoperative MR imaging revealed improvement in the spinal cord deformity, although the intramedullary hyperintensity was still observed in most cases. The present study demonstrates the importance of associated disc protrusion in the development of myelopathy in patients with cervical OPLL. Magnetic resonance imaging findings may be used to help determine the actual levels of spinal cord compression and to suggest the method of surgical treatment.

✓ A number of operative techniques have been described for the treatment of herniated thoracic discs. The transfacet pedicle-sparing approach allows for complete disc removal with limited spinal column disruption and soft-tissue dissection. Fifteen cadaveric spinal columns were used for evaluation of exposure, development of thoracic microdiscectomy instrumentation, and establishment of morphometric measurements. This approach was used to remove eight thoracic discs in six patients. Levels of herniation ranged from T-7 through T-11. Preoperatively, all patients had moderate to severe axial pain, and three (50%) of the six had radicular pain. Myelopathy was present in four (67%) of the six patients. Through a 4-cm opening, the ipsilateral paraspinal muscles were reflected, and a partial facetectomy was performed. The disc was then removed using specially designed microscopic instrumentation. Postoperatively, the radiculopathy resolved in all patients. Axial pain and myelopathy were completely resolved or significantly improved in all patients. The minimal amount of bone resection and muscle dissection involved in the operation allows for: 1) decreased operative time and blood loss; 2) diminished perioperative pain; 3) shorter hospitalization time and faster return to premorbid activity; 4) avoidance of closed chest tube drainage; and 5) preservation of the integrity of the facet—pedicle complex, with potential for improvement in outcome related to axial pain. This technique appears best suited for the removal of all centrolateral discs, although it has been used successfully for treating a disc occupying nearly the entire ventral canal. The initial experience suggests that this approach may be used to safely remove appropriately selected thoracic disc herniations with good results.

✓ Extreme-lateral lumbar disc herniations present a surgical challenge because the conventional posterior approach requires bone resection for complete visualization of the pathology. The authors have identified constant anatomical landmarks in cadaveric dissections that facilitate access to the intervertebral foramen when combined with a posterolateral approach, as described by Watkins, for lumbar spinal fusion. The authors describe a technique that allows rapid localization and safe excision of these extreme-lateral lumbar disc herniations without the need for bone resection.

✓ A series of 283 patients who suffered from cervical spondylosis, herniated disc, or traumatic pathology of the cervical spine were operated on using an anterior approach. Intersomatic arthrodesis was performed in 350 cases; in every case, a threaded bone graft was screwed into the intervertebral orifice using the technique described by the author. Fusion was achieved within 6 months in 93% of cases with 92 autologous grafts and in 81% of cases with 258 heterologous grafts. In addition to the use of threaded intervertebral holes and threaded bone grafts, the Cloward technique was modified by the introduction of a set of new instruments, which largely replaced the ones previously in use. These included a low-speed motor with different drills and trephines, a trephine guide retractor, and an intersomatic retractor.

✓ Lumbar epidural varices have been infrequently described in the literature and rarely accepted as a primary pathophysiological entity. The authors' total experience with symptomatic lumbar epidural varices over the last 15 years includes four cases (incidence 0.067% of all lumbar spine operations), two of which are described in detail in this paper. The mechanism for their formation is proposed: central disc herniations obstruct the anterior epidural venous flow leading to anterolateral caudal venous distention. Subsequent venous endothelial injury predisposes to varying degrees of phlebothrombosis. Decompression of partially thrombosed varices may occur during operative discectomy or spontaneously during regression of the nonoperated disc prolapse. Regression of the central disc herniation may also explain the “disappearing disc” phenomenon, in which patients with clinical and radiographic evidence of apparently large caudal disc herniations exhibit clinical and radiographic resolution. Magnetic resonance (MR) imaging characteristics of the epidural varix depend upon the degree of thrombosis within this anomaly. A thrombosed varix is hyperintense on T1-weighted, proton-density, and T2-weighted images, whereas flowing blood is hypointense. The variable hypo- and hyperintensity on the T2-weighted MR imaging sequences correlate with a partially patent lumen within the varix.

✓ The introduction of microdiscectomy to lumbar spine surgery has resulted in a significant decrease in postoperative pain and length of hospital stay. Intraoperative application of long-acting local anesthetic agents has been used for many general and neurosurgical procedures for the management of postoperative pain. In addition, many surgeons routinely use intraoperative corticosteroids during lumbar discectomy to reduce traumatic nerve root inflammation. However, the efficacy of intraoperative long-acting local anesthetic agents and corticosteroids for reduction of postoperative discomfort has not been reported for lumbar discectomy. This study evaluated 32 patients at a university-based Veterans Administration hospital undergoing lumbar microdiscectomy. All 32 patients presented with radicular symptoms and had radiographic confirmation of a herniated nucleus pulposus. These patients were divided into three groups. Group 1 (12 patients) received 160 mg intramuscular Depo-Medrol (methylprednisolone acetate) and 250 mg intravenous Solu-Medrol (methylprednisolone sodium succinate) at the start of the operation. A macerated fat graft soaked in 80 mg Depo-Medrol was placed over the affected nerve root following discectomy. In addition, 30 ml of 0.25% bupivacaine was infiltrated into the paraspinal musculature at skin incision and during closure. Group 2 (10 patients) received 30 ml of 0.25% bupivacaine infiltrated into the paraspinal musculature at skin incision and at closure. In this group of patients, a saline-soaked fat graft was placed over the affected nerve root. Group 3 (10 patients) acted as a control group, undergoing lumbar microdiscectomy without corticosteroids or bupivacaine. Patients receiving bupivacaine and corticosteroids (Group 1) had a statistically significantly shorter hospital stay (1.4 days) compared to the control group (4.0 days) (p = 0.0004, Mann-Whitney U-test). Patients in Group 1 required less postoperative narcotic analgesia than the other groups. Finally, a larger percentage of patients in Group 1 reported complete relief of back and radicular pain on postoperative Day 1 compared to other groups. Postoperative complications and functional outcome were not different between the groups. These results indicate that the combination of long-acting anesthetic agents and corticosteroids can reduce postoperative discomfort and subsequently the length of postoperative hospital stay.

✓ Percutaneous endoscopic discectomy is a new technique for removing “contained” lumbar disc herniations (those in which the outer border of the anulus fibrosus is intact) and small “noncontained” lumbar disc herniations (those at the level of the disc space and occupying less than one-third of the sagittal diameter of the spinal canal) through a posterolateral approach with the aid of specially developed instruments. The technique combines rigid straight, angled, and flexible forceps with automated high-power suction shaver and cutter systems. Access can thus be gained to the dorsal parts of the intervertebral space where the disc herniation is located. Percutaneous endoscopic discectomy is monitored using an endoscope angled to 70° coupled with a television and video unit and is performed with the patient under local anesthesia and an anesthesiologist available if needed. Its indication is restricted to discogenic root compression with a minor neurological deficit. Two groups of patients with contained or small noncontained disc herniations were treated by either percutaneous endoscopic discectomy (20 cases) or microdiscectomy (20 cases). Both groups were investigated in a prospective randomized study in order to compare the efficacy of the two methods. The disc herniations were located at L2–3 (one patient), L3–4 (two patients), or L4–5 (37 patients). There were no significant differences between the two groups concerning age and sex distribution, preoperative evolution of complaints, prior conservative therapy, patient's occupation, preoperative disability, and clinical symptomatology. Two years after percutaneous endoscopic discectomy, sciatica had disappeared in 80% (16 of 20 patients), low-back pain in 47% (nine of 19 patients), sensory deficits in 92.3% (12 of 13 patients), and motor deficits in the one patient affected. Two years after microdiscectomy, sciatica had disappeared in 65% (13 of 20 patients), low-back pain in 25% (five of 20 patients), sensory deficits in 68.8% (11 of 16 patients), and motor deficits in all patients so affected. Only 72.2% of the patients in the microdiscectomy group had returned to their previous occupation versus 95% in the percutaneous endoscopic discectomy group. Percutaneous endoscopic discectomy appears to offer an alternative to microdiscectomy for patients with “contained” and small subligamentous lumbar disc herniations.

✓ Meningeal enhancement on magnetic resonance (MR) imaging is considered the hallmark radiological feature of intracranial hypotension. The authors report on a patient who exhibited progressively symptomatic intracranial hypotension due to a lumbar cerebrospinal fluid (CSF) leak, but in whom MR imaging demonstrated no pachymeningeal enhancement.This 24-year-old man presented with a 6-week history of progressive orthostatic headaches that were associated with photo- and phonophobia. Four weeks before the onset of the headaches, the patient had undergone a lumbar laminectomy. Brain MR images revealed subdural fluid collections and brain sagging; however, meningeal enhancement was not present. Myelography demonstrated a CSF leak at the site of the laminectomy. At surgery, a large dural tear was repaired. The patient recovered well from the surgery, with complete resolution of his headaches.The absence of meningeal enhancement on MR imaging does not exclude a diagnosis of symptomatic intracranial hypotension.

Neurological surgery was defined as a separate surgical specialty by Harvey Cushing and a few other surgeons, most of whom were trained and influenced by Cushing. One of these, Raphael Eustace Semmes, became the first neurosurgeon in Memphis, Tennessee, in 1912. After World War II, Semmes and his first associate, Francis Murphey, incorporated the Semmes-Murphey Clinic, which has been primarily responsible for the growth of the Department of Neurosurgery at the University of Tennessee Health Science Center in Memphis, as well as the development of select neurosurgical subspecialties in Memphis area hospitals.

✓ The cases of 29 patients with cervical myelopathy, who had been treated by anterior spine fusion, were reviewed. The relationship between pre- and postoperative magnetic resonance (MR) images was investigated with special reference to increased signal intensity in the spinal cord on the T2-weighted images and the relevance of this finding to clinical conditions. Preoperatively, there were areas of increased signal intensity in 12 patients whereas there were no areas of increased signal intensity in the other 17. The lesions were not clearly demonstrated on T1-weighted images. The pre- and postoperative clinical condition of the patients whose preoperative MR images showed areas of increased signal intensity in the spinal cord on T2-weighted images was worse than that of the patients who did not have areas of increased signal intensity. Of the 12 patients with regions of increased signal intensity preoperatively, five showed decreased signal intensity postoperatively compared to the preoperative levels and seven had no change. The postoperative recovery of the five patients who showed decreased signal intensity postoperatively was better than that of the seven patients who exhibited no change. The areas of increased MR signal in the spinal cord might be due to edema, cord gliosis, demyelination, or microcavities.

✓ A case of cervical spine injury related to bungee jumping is presented. Surgical intervention resulted in resolution of the patient's quadriparesis. The incidence of serious injury connected with this pastime is not inconsiderable, and it is recommended that safer jumping practices be followed. Inspection of bungee equipment and certification of instructors is now voluntary but should be mandated. Jumping heights should be limited and the use of air cushions encouraged.

Lumbar disc herniation and spinal epidural hematomas (SEHs) are highly unusual causes of secondary lumbar canal stenosis in the adolescent population. The authors report a unique concomitant occurrence in a 16-year-old boy who presented with left-sided L-5 radiculopathy. Magnetic resonance imaging T1-weighted sequences revealed a left-sided posterolateral prolapsed L4-5 disc with an isointense extruded fragment lying behind the L-5 body. On T2-weighted sequences a hyperintense area was seen in the region of the extruded disc fragment with thecal compression. At surgery the extradural encapsulated hematoma was removed, together with the extruded disc fragment and the L4-5 disc. The characteristics of the biopsy specimen from the epidural collection were consistent with those of a hematoma. At 6 months' follow up, the patient had returned to his normal activities. An SEH may result from tearing of delicate epidural veins following disc extrusion. It can occur at any age, regardless of whether there is a history of significant trauma. Magnetic resonance imaging allows preoperative characterization of the lesion. Results after surgical evacuation are excellent. Distinguishing between a solitary SEH and one caused by a lumbar disc extrusion has significant implications, as the former may resolve completely with conservative management.

✓ Automated percutaneous discectomy has been performed in 57 patients at the author's institution since 1989, representing 4% of all lumbar spine surgeries. All 57 patients had unilateral sciatica. There were 33 women and 24 men ranging from 24 to 49 years of age, with a mean age of 45 years. All patients underwent computerized tomography (CT) in the prone position and CT and magnetic resonance imaging in the supine position. Diffuse versus eccentric disc bulging was determined for each patient. Four patients underwent surgery at the L3–4 level, four at L5–S1, and 49 at L4–5. One L5–S1 case could not be cannulated and surgery was aborted. There have been no complications related to surgery. Fifty patients (88%) stated they had reduced sciatica in the first 2 postoperative weeks. Forty (70%) had reduced sciatica 2 months postoperatively. The mean follow-up period was 27 months (range 6 to 45 months), with no patient lost to follow up. At their last follow-up examination, 33 patients (58%) showed improvement in their sciatica but only three (5%) were completely pain free. Of the 17 recurrences of sciatica, 11 patients have undergone microdiscectomy, with eight showing improvement. Chi-square analysis demonstrated a significantly better chance of improvement in patients with discs bulging eccentrically to the side of sciatica (p < 0.05) compared to patients with diffusely bulging discs. Automated percutaneous discectomy is safe and in selected patients can reduce sciatica, but only completely eliminated sciatica in 5% of patients with a follow-up period of 2.5 years.

Object. It is not known whether changes in intraradicular blood flow (IRBF) occur during the femoral nerve stretch test (FNST) in patients with lumbar disc herniation. An FNST was conducted in patients with lumbar disc herniation to observe the changes in IRBF, and results were then compared with clinical features. Methods. The study was composed of four patients with L3–4 disc herniation who underwent microdiscectomy. Patients were placed prone immediately before surgery, so that their knee flexed on the operating table with the hip joint kept in hyperextension, and the FNST was performed to confirm at which region pain developed in the anterolateral thigh. During the operation, the hernia-affected nerve roots were visualized under a microscope. The needle sensor of a laser Doppler flowmeter was then inserted into each nerve root immediately above the hernia, and the change in IRBF was measured during the intraoperative FNST. After removal of the herniated disc, a similar procedure was repeated and IRBF was measured again. The intraoperative FNST showed that the hernia compressed the nerve roots and there was marked disturbance of gliding, which was reduced to only a few millimeters. During the test, IRBF decreased by 92.8 to 100% (mean 96.9 ± 3.7% [± standard error of the mean]) relative to the blood flow before the test. This study demonstrated that the blood flow in the nerve root is reduced when the nerve root is compressed in vivo. Conclusions. The intraoperative FNST showed that the hernia compressd the nerve roots and there was marked disturbance of gliding, which was reduced to only a few millimeters. During the test, IRBF decreased by 92.8 to 100% (96.9 ± 3.7% [mean ± standard error of the mean]).

✓ Spontaneous intracranial hypotension (SIH) may result from occult leaks anywhere along the neuraxis. Although this syndrome has been recognized over the past 10 years in the neurology and radiology literature, the typical magnetic resonance (MR) imaging picture and clinical course are less well known to neurosurgeons. The authors describe the case of a patient with positional headache and MR imaging findings typical of SIH that resulted from an intradural disc herniation.

Object. Placing instrumentation in the anterior cervical spine is a common procedure. The bi- and unicortical systems currently available, however, have distinct advantages and disadvantages. The author reports a prospective series in which a new dynamized anterior cervical fixation system was evaluated. Methods. Thirty-seven patients underwent anterior cervical discectomy and fusion in which the DOC ventral cervical stabilization system was used for indications including cervical spondylotic radiculopathy, disc herniation, trauma, and myelopathy. Patients underwent anterior cervical discectomy and interbody fusion and/or corpectomy. Preoperative and postoperative clinical data included assessment of spinal cord and nerve root deficit, function, neck pain, and arm pain. Preoperative and postoperative radiographic data included sagittal angle, translation, and settling of the graft. Fusion status was determined by the presence of trabecular bridging bone on plain anteroposterior and lateral cervical radiographs. At a mean follow-up time of 1.3 years, postoperative neck or arm pain was resolved in 52% of the patients, restriction on function was mild or absent in 88%, and fusion was successful in 80% of patients and 88% of the treated levels. There was one implant-related complication, one significant dysphagia complication, and a 10.8% donor graft site complication rate. Conclusions. The use of this system led to a high percentage of pain relief and radiographic fusion. The sagittal angle was controlled while allowing for graft settling. There were no implant failures.

Object. The present investigation evaluates two thicknesses of a resorbable polylactic acid (PLA) barrier film as an adhesion barrier to posterior spinal scar formation. Methods. A readily contourable, thin film was placed directly over the dura. The thick film was placed above the lamina defect to act as a physical barrier inhibiting the prolapse of soft tissue into the epidural space. Through a combination of gross dissection with and without scar scores, quantitative analysis of collagen adjacent to the scar site, and histological evaluation, the resorbable adhesion barrier membranes were found to be effective treatment for reduction of posterior adhesions. Conclusions. The gross dissection demonstrated that both thicknesses of resorbable PLA barrier films created a controlled dissection plane, facilitated access to the epidural space, and provided a reduction in the tissue adherent to the dura.

Object. The authors conducted a study to determine the results of decompressive surgery without fusion in selected patients who presented with radicular compression syndromes caused by degenerative lumbar spondylolisthesis and in whom there was no evidence of hypermobility on flexion—extension radiographs. Methods. The medical records and radiographs obtained in 49 patients were reviewed retrospectively. Clinical status was quantified by summing self-assessed Prolo Scale scores. All 49 patients (55% female, mean age 68.7 years) presented with leg pain accompanied by lumbalgia in 85.7% of the cases. Preoperatively the median sum of Prolo Scale scores was 4. The mean preoperative degree of forward vertebral displacement was 13.5% and was located at L-4 in 67% of the cases. Osseous decompression alone was performed in 53%, and an additional discectomy at the level of displacement was undertaken in the remaining patients because of herniated discs. Major complications (deep wound infection) occurred in 2%. During a mean follow-up period of 3.73 years, 10.2% of the patients underwent instrumentation-assisted lumbar fusion when decompression alone failed to resolve symptoms. At last follow up the median overall Prolo Scale score was 8. Excellent and good results were demonstrated in 73.5% of the patients. Prolonged back pain (r = 0.381) as well as the preoperative degree of displacement (r = 0.81) and disc space height (r = 0.424) influenced outcome (p ≤ 0.05); additional discectomy for simultaneous disc herniation at the displaced level did not influence outcome (p > 0.05). Conclusions. These results appear to support a less invasive approach in this subgroup of elderly patients with degenerative lumbar spondylolisthesis—induced radicular compression syndromes and without radiographically documented hypermobility. Additional discectomy for simultaneous disc herniation of the spondylolisthetic level did not adversely influence the outcome. Complication rates are minimized and fusion can eventually be performed should decompression alone fail. A prospective controlled study is required to confirm these results.

✓ A case of a dural arteriovenous fistula (DAVF) that developed at the site of nerve root sleeve damage as a result of lumbar disc extrusion is reported. A 60-year-old man who had undergone lumbar discectomy 3 years previously for severe left-sided sciatica and L5—S1 disc herniation presented with progressive gait disturbance. After the initial surgery, the symptoms resolved. Fourteen months after the operation, however, he started to experience dysesthesias in both legs and progressive gait and urinary disturbances. Physical examination revealed a weakness of the anterior tibialis and the gastrocnemius muscles, as well as decreased contractility of the anal sphincter and marked sacral hypesthesia. Magnetic resonance (MR) imaging revealed swelling and a T2 signal elongation in the conus medullaris; angiography demonstrated arteriovenous dural shunting between the left lateral sacral artery and the left S-1 radicular vein at the site of the previous operation. Surgery was conducted to excise the DAVF on the S-1 nerve root sleeve and an arterialized intradural vein on the root. The procedure resulted in resolution of the symptoms and disappearance of the abnormal angiographically and MR imaging—documented anomalies. This is the first report of a DAVF in which progressive conus myelopathy developed after a lumbar discectomy.

Object. The authors review their experience in the diagnosis and management of 32 patients with slitlike syrinx cavities. Methods. There were 18 men and 14 women with a mean age of 40 years. Presenting symptoms that prompted magnetic resonance (MR) imaging evaluation were mechanical spinal pain (13 patients), radicular pain (seven patients), paresthesia (six patients), numbness (five patients), and muscle spasm (one patient). In 12 patients neurological examination demonstrated normal status, and in the remainder only minimal sensory or motor abnormalities were found. The mean diameter of the syrinx cavity was 2 mm (range 1–5 mm), and on average it covered three vertebral levels. The cavities were limited to the cervical region in 16 patients, the thoracic in 12, and both regions in four patients. The mean follow-up time for changes in clinical condition and repeated MR imaging features were 38 and 32 months, respectively. Thirty-one patients were treated nonoperatively, and one was treated surgically. During the follow-up period clinical improvement was documented in six patients, worsened status in seven, and no change was demonstrated in the clinical status of 19 patients. None of the syrinx cavities changed in size. In 16 patients medical workup revealed alternative diagnoses that were determined to be the true causes of each patient's symptoms. Conclusions. Slitlike cavities likely do not represent true syringomyelia but rather remnants of the central canal detected in a small percentage of adults. Review of the authors' experience indicates that these cavities are asymptomatic and are unlikely to change in size. They can be considered an incidental finding, and in many of these patients another condition explaining the patient's symptoms may be found.

Object. The authors compare clinical outcomes demonstrated in patients with traumatic central cord syndrome (CCS) who underwent early (< 24 hours after injury) or late (> 24 hours after injury) surgery. Methods. The clinical characteristics, radiographic findings, surgery-related results, length of hospital stay (LOS), and clinical outcomes obtained in 50 patients with surgically treated traumatic CCS were reviewed retrospectively. Shorter intensive care unit (ICU) stay and LOS were observed in all patients who underwent early surgery compared with those who underwent late surgery. In patients with CCS secondary to acute disc herniation or fracture/dislocation who underwent early surgery significantly greater overall motor improvement was observed than in those who underwent late surgery (p = 0.04). Overall motor outcome in patients with CCS secondary to spinal stenosis or spondylosis who underwent early surgery was not significantly different from that in those who underwent late surgery (p = 0.51). Worse motor outcomes were found in patients who were older than 60 years of age and in whom initial bladder dysfunction was present (p = 0.03 and 0.02, respectively) compared with younger patients without bladder dysfunction. Conclusions. Early surgery is safe and more cost effective than late surgery for the treatment of traumatic CCS, based on ICU stay and LOS and improved overall motor recovery, in patients whose CCS was related to acute disc herniation or fracture. In the setting of spinal stenosis or spondylosis, early surgery was safe but did not improve motor outcome compared with late surgery.

✓ Spontaneous intracranial hypotension is frequently idiopathic. The authors report on a patient presenting with symptomatic intracranial hypotension caused by a transdural calcified thoracic disc herniation. Cranial magnetic resonance (MR) imaging revealed classic signs of intracranial hypotension, and a combination of spinal MR and computerized tomography myelography confirmed a mid-thoracic transdural calcified herniated disc as the cause. The patient was treated with an epidural blood patch and burr hole drainage of the subdural effusion on two occasions. Postoperatively the headache resolved and there was no neurological deficit. Thoracic disc herniation may be a cause of spontaneous intracranial hypotension.

Object. In this report the author presents surgery-related outcomes after application of a new technique. A posterior microendoscopic laminoforaminotomy was used for the surgical treatment of unilateral cervical radiculopathy secondary to intervertebral disc herniations and/or spondylotic foraminal stenosis. The results of this procedure are compared with those achieved using traditional laminoforaminotomy and anterior cervical discectomy with or without fusion. Methods. One hundred consecutive patients who experienced unilateral cervical radicular syndromes, which were refractory to conservative therapy, and in whom imaging studies had confirmed lateral canal or foraminal compression, underwent surgical treatment. An endoscopy-assisted posterior laminoforaminotomy was performed using a microendoscopic visualization system for removal of herniated disc and foraminal decompression while the patient was in the sitting position. Excellent or good results were obtained in 97 patients, who returned to their preoperative employment and baseline level of physical activity. One patient returned to work but was unable to perform at baseline level; two patients returned to prior sedentary work but continued to have some activity-related pain and paresthesias. Two patients reported experiencing intermittent paresthesias or numbness, but this did not limit their activities. There were two cases of dural punctures, one case of superficial wound infection, and no deaths. Conclusions. The microendoscopic posterior laminoforaminotomy is an effective alternative for the treatment of unilateral cervical radiculopathy secondary to lateral or foraminal disc herniations or spondylosis. In this group of patients, it is preferable because it does not require the sacrifice of a cervical motion segment, has a low incidence of complications, and is associated with a much quicker return to unrestricted full activity than that obtained with other techniques.

Object. The authors retrospectively reviewed a series of 35 patients with mechanical low-back or one- to two-level discogenic pain; the patients underwent lumbar interbody fusion in which threaded cortical bone dowels (TCBDs) were placed to treat degenerative disc disease. The purpose of the study was to delineate fusion rates and outcome data in this series of patients. Methods. The series was composed of 18 women and 17 men whose mean age was 46 years (range 17–76 years). There were nine active cigarette smokers. All patients presented with symptoms consistent with mechanical low-back or discogenic pain, and magnetic resonance imaging revealed degenerative changes related to disc collapse at one or two vertebral levels. For placement of the TCBDs, 23 patients underwent posterior lumbar interbody fusion (PLIF), whereas 12 patients underwent anterior lumbar interbody fusion (ALIF). In all except one patient undergoing PLIF, pedicle screw and rod constructs were used without posterolateral fusion. In all patients undergoing ALIF except one, TCBDs were used as stand-alone devices without supplemental fixation. At follow up the success of fusion was determined by static lumbar radiography and/or computerized tomography scanning. The degree of lumbar lordosis at the diseased level was measured immediately postoperatively and compared with that documented on follow-up radiological studies. Outcomes were assessed using a modified Prolo Scale. Excellent and good outcomes were considered satisfactory, and fair or poor outcomes were considered unsatisfactory. In 28 patients (eight ALIF and 20 PLIF) radiological and clinical follow-up data were considered adequate. The mean follow-up duration was 12.3 months. Overall satisfactory outcome was 60%; 70% satisfactory outcome was noted in PLIF patients and 38% in ALIF patients. Osseous fusion was present in 95% of the patients in the PLIF group and in 13% of those in the ALIF group. Complications included one L-5 nerve root injury and two postoperative wound infections, all in patients who underwent PLIF; in an ALIF patient lateral breakout of one implant occurred at 8 months postoperatively. Conclusions. Analysis of the mean 12.3 month follow-up data indicates that there is a dramatically higher fusion rate in PLIF compared with ALIF procedures when TCBDs are used. The authors believe that it is important to note that in all the PLIF procedures except one, supplemental pedicle screw/rod constructs were used, whereas in ALIF procedures no supplemental fixation was performed. The results thus suggest that TCBDs are best used in PLIF in conjunction with pedicle screw and rod constructs.

Object. Of concern to spine surgeons are accelerated degenerative changes of motion segments located above and below where spinal fusion has been performed. Graf artificial ligament stabilization has been developed to avoid the adverse effect of spinal fusion. The object of this study was to assess the adjacent-segment morbidity of Graf ligamentoplasty compared with posterolateral fusion (PF) in which instrumentation was used. Methods. Data obtained in 45 patients who underwent L4–5 Graf ligamentoplasty (18 patients) or PF with instrumentation (27 patients) were reviewed retrospectively. The minimum follow-up period was 5 years. In the PF group a solid fusion rate of 92.6% was achieved. Radiographic evaluation included assessment of lumbar sagittal alignment, range of motion (ROM), and adjacent-disc degeneration. Adjacent-segment morbidity was clinically assessed by determining the reoperation rate. Graf ligamentoplasty maintained regional lordosis and flexibility (13° in L4–5 lordosis; 4.4° in L4–5 ROM). Although there was no difference in preoperative adjacent-disc condition between the two groups, radiographic evidence of adjacent-disc deterioration was observed more frequently in patients in the PF group than the Graf group (25% and 6% at L1–2; 38% and 6% at L2–3; 38% and 18% at L3–4; and 43% and 18% at L5—sacrum, respectively). One case in the Graf group (5.6%) and five cases in the PF group (18.5%) required additional surgeries for adjacent-segment lesions. Conclusions. Graf ligamentoplasty cannot completely replace spinal fusion. In a well-selected group of patients, however, it was shown to maintain lumbar mobility and sagittal alignment, and it decreased the risk of adjacent-segment deterioration compared with PF with instrumentation.

Object. Far-lateral (extraforaminal) and foraminal disc herniations comprise up to 11% of all herniated intervertebral discs. Operative management can be technically difficult, and the optimum surgical treatment remains controversial. Accessing these lateral disc herniations endoscopically via a percutaneous transforaminal approach offers several theoretical advantages over the more traditional procedures. The object of this study was to assess the safety and efficacy of treating patients with far-lateral and foraminal disc herniations via a percutaneous transforaminal endoscopic approach. Methods. A retrospective analysis was performed of 47 consecutive patients who underwent surgery via this approach. All procedures were performed after induction of a local anesthetic on an outpatient basis. Outcome was measured with Macnab criteria and by determining a patient's return-to-work status. The median follow-up period was 18 months (range 4–51 months). Excellent or good outcome was obtained in 40 (85%) of 47 patients. Of the 38 patients working before the onset of symptoms, 34 (90%) returned to work. Five patients (11%) experienced poor outcomes and subsequently underwent open procedures at the same level. Of the 10 recipients of Workers' Compensation, Macnab criteria indicated a significantly worse outcome (70% excellent or good), but an excellent return-to-work status was maintained (90%). There were no complications. Conclusions. Transforaminal percutaneous endoscopic discectomy is safe and efficacious in the treatment of far-lateral and foraminal disc herniations.

✓ Although cervical disc herniation commonly requires surgical intervention, the intradural sequestration of a herniated cervical disc fragment is rare. In searching the world literature on this topic, the authors found six case reports. They report three new cases of intradural cervical disc herniation in which the patients presented with Brown—Séquard's syndrome and they review the literature. Although Brown—Séquard's syndrome is a rare clinical finding in extradural disc herniation, six of the nine patients with intradural cervical disc herniation (our cases and those from the literature) presented with symptoms of this syndrome. The remaining patients presented with para- or quadriparesis. This suggests that intradural disc herniation should be considered preoperatively in patients in whom there is magnetic resonance imaging or myelographic evidence of cervical disc herniation and Brown—Séquard's syndrome. In patients who underwent anterior cervical discectomy for the treatment of intradural cervical disc herniations, better outcomes were demonstrated than in those in whom posterior procedures were performed.

✓ The authors describe a rare case of an intradural cervical disc herniation in a 40-year-old man presenting with Brown—Séquard's syndrome. Magnetic resonance imaging revealed the pathological entity at the C5–6 disc space, which showed suspicious signs of intradural extension of the disc herniation. After the patient underwent microsurgical removal of the herniated disc via an anterior approach, he experienced a complete remission of symptoms. The existing pertinent literature is reviewed, and diagnostic and therapeutic implications are discussed.

Object. The aim of this study was to investigate different variables in the duration of symptoms that can be used to predict outcome after lumbar microdiscectomy. Methods. In a prospective study of 132 consecutive patients who underwent surgery for lumbar disc herniation, the authors evaluated the prognostic value of different variables in the duration of symptoms for the 1-year period after surgery. The 1-year follow-up investigation was conducted by an independent observer. Assessment of outcome was performed using a clinical overall score (COS), which was recently assessed for its reliability and validity. As for factors predictive of outcome, only duration of leg pain and sick leave reached statistical significance in the multivariate analysis. Results of the univariate analysis demonstrated that in patients experiencing preoperative leg pain fewer than 4 months and between 4 and 8 months, a significantly lower COS at the 1-year follow up was demonstrated compared with those in whom the duration of leg pain was longer (> 8 months). One hundred eight patients returned to work within the 1st year after surgery. Patients who took a sick leave of more than 28 weeks before the operation were at higher risk of not returning to work. Conclusions. Analysis of these results indicates that leg pain lasting more than 8 months correlates with an unfavorable postoperative outcome in patients with lumbar disc herniation, as well as a high risk of not returning to work.

Object. In this study the authors retrospectively review 16 patients with traumatic disc herniation secondary to middle and lower cervical spine injuries who underwent a single posterior reduction and fusion procedure in which a cervical pedicle screw system was used. The study was undertaken to evaluate whether the procedure effectively reduced the disc herniation and whether it can be safely conducted without performing anterior decompressive surgery. Methods. A total of 73 patients with middle and lower cervical spine injuries were identified. In 50 patients, pre- and postoperative magnetic resonance (MR) images were obtained, and disc herniation was defined as the presence of an extruded disc that deformed the thecal sac or nerve roots. Traumatic disc herniation was revealed in 16 patients (32%) who underwent a single posterior reduction/fusion procedure in which a cervical pedicle screw system was used. The average follow-up period was 4.25 years (2–6.25 years). In all patients the average kyphotic deformity was 18°, which was corrected to 0.7° lordosis postoperatively. Anterior translation was reduced from 8 to 0.7 mm. The preoperative disc height ratio of 63% (normal 100%) was improved to 104%. Preoperative MR images revealed traumatic disc herniation in all 16 patients; postsurgery, reduction or reversal of disc herniation was observed in all patients. Thecal sac and/or spinal cord compression had disappeared after indirect decompression was achieved using a posterior procedure. No additional decompressive procedures were required to remove residual herniated disc material. Preoperatively, four patients presented with cervical radiculopathy, 10 with myelopathy (eight incomplete and two complete), and two without neurological symptoms. At final follow up, complete recovery was observed in all four patients with radiculopathy and improvement of at least one Frankel grade was shown in six patients (60%) with myelopathy. There were no cases of neurological deterioration immediately after surgery or during the course of the follow-up period. In all patients solid bone union was demonstrated, and there were no implant-related complications. Conclusions. Traumatic disc herniation may occur frequently in association with injury of the cervical spine. The incidence of traumatic disc herniation in our series was 32%. The cervical pedicle screw system allowed three-dimensional reduction of the injured cervical segment and reduction or reversal of a disc herniation. After surgery, compression of the thecal sac and/or spinal cord had disappeared. The cervical pedicle screw system provides effective and safe fixation of the cervical spine injury—related traumatic disc herniation, and the surgery can be performed safely in a single posteriorapproach procedure without need of additional anterior decompressive interventions.

U The occurrence of disc herniation is rare in children. A 27-month-old child fell from his cradle and developed, in the following 2 weeks, irritability, low-back pain, and difficulty in walking. On physical examination a compensatory gait, paravertebral muscle spasm, and a restricted right straight-leg raising test were demonstrated. Plain x-ray films revealed a narrowed L4–5 intervertebral space. Magnetic resonance imaging of the lumbosacral spine demonstrated decreased signal in the L4–5 disc, with posterior disc protrusion. At surgery, blood infiltrating the subperiosteal plane was observed. Via a left hemilaminectomy and under microscopic magnification, the left L-5 nerve root was found to be intact, and on the right side significant nerve root compression was identified. During dissection an accidental dural tear occurred. A right L-4 hemilaminectomy was performed, and the disc fragments were removed until a complete nerve root decompression was obtained and the dura was repaired. The child recovered uneventfully and was asymptomatic 7 years postsurgery. This child is one of the youngest patients with a herniated disc reported in the world literature. The authors discuss the diagnostic difficulties and management of this entity in children.

Object. In this review the authors address the surgical strategies required to resect residual herniated thoracic discs. Methods. Data obtained in 15 patients who had undergone prior thoracic discectomy and who harbored residual or incompletely excised symptomatic thoracic discs were reviewed retrospectively. The surgical procedures that had failed to excise the herniated discs completely included 11 posterolateral approaches, one thoracotomy, and three thoracoscopyguided surgical procedures. Of the lesions that were incompletely resected or residual, there were 13 central calcified, two soft, 12 extradural, and three intradural discs. Indications for reoperation were often multiple in each patient and included misidentification of the level of disc disease at the initial operation (five cases), abandoning the procedure because of intraoperative spinal cord injury (three cases), inadequate visualization of the pathological entity (eight cases), migration of a soft disc fragment within the spinal canal (one case), and intradural disc extension (three cases). The symptoms at the time of reoperation included myelopathy in 13 patients and radicular pain in two patients. The mean interval before reoperation was 150 days (range 1 day–4 years). The reoperation procedures included one thoracotomy and 14 video-assisted thoracoscopic procedures performed ipsilateral (11 cases) or contralateral (four cases) to the site of the initial surgery. The herniated disc material was excised completely in all 15 cases without causing new neurological deficits. Reoperation complications included atelectasis in three patients, intercostal neuralgia in two, a loosened screw that required removal in one, residual intradural disc herniation that required a second reoperation in one patient, and a cerebrospinal fluid leak in one patient. Of the 13 patients who experienced myelopathy prior to operation, 10 recovered neurological function and three stabilized. All patients with radicular pain improved. Conclusions. Calcified, large, broad-based, centrally located, or transdural thoracic disc herniations can be difficult to resect. These lesions require a ventral operative approach to visualize the dura adequately for a safe and complete resection.

Object. The authors retrospectively reviewed 121 patients with traumatic cervical spine injuries to determine the risk of neurological deterioration following early closed reduction. Methods. After excluding minor fractures and injuries without subluxation, the medical records and imaging studies (computerized tomography and magnetic resonance [MR] images) of 82 patients with bilateral and unilateral locked facet dislocations, burst fractures, extension injuries, or miscellaneous cervical fractures with subluxation were reviewed. Disc injury was defined on MR imaging as the presence of herniation or disruption: a herniation was described as deforming the thecal sac or nerve roots, and a disruption was defined as a disc with high T2-weighted signal characteristics in a widened disc space. Fifty-eight percent of patients presented with complete or incomplete spinal cord injuries. Thirteen percent of patients presented with a cervical radiculopathy, 22% were intact, and 9% had only transient neurological deficits in the field. Early, rapid closed reduction, using serial plain radiographs or fluoroscopy and Gardner—Wells craniocervical traction, was achieved in 97.6% of patients. In two patients (2.4%) closed reduction failed and they underwent emergency open surgical reduction. The average time to achieve closed reduction was 2.1 ± 0.24 hours (standard error of the mean). The incidence of disc herniation and disruption in the 80 patients who underwent postreduction MR imaging was 22% and 24%, respectively. However, the presence of disc herniation or disruption did not affect the degree of neurological recovery, as measured by American Spinal Injury Association motor score and the Frankel scale following early closed reduction. Only one (1.3%) of 80 patients deteriorated, but that occurred more than 6 hours following closed reduction. Conclusions. Although disc herniation and disruption can occur following all types of traumatic cervical fracture subluxations, the incidence of neurological deterioration following closed reduction in these patients is rare. The authors recommend early closed reduction in patients presenting with significant motor deficits without prior MR imaging.

Object. Knowledge is scarce about movement disorders that follow neurosurgical operations other than functional stereotactic surgery. The cases of 14 patients who suffered from movement disorders secondary to craniocerebral or spinal surgery are analyzed. None of these patients was initially treated by any of the authors.Methods. Twelve patients underwent surgery for cerebral diseases. Nine of these patients harbored tumors and three patients had neurovascular disorders. Two patients underwent spinal surgery for cervicothoracic ependymoma or for multiple cervical disc herniations. Twelve of the 14 patients had immediate postoperative side effects such as hemiparesis, ataxia, and somnolence. In all but two patients, movement disorders became manifest only after a delay.Dystonic movement disorders developed in eight patients, unilateral tremors in three patients, unilateral facial myokymia in one patient, and hemichorea—hemiballism in two patients. The mean delay of onset for tremor was 5 weeks and that for dystonic movement disorders was 5.5 months. Movement disorders were transient in three patients; however, they were persistent in 11 patients at a mean follow-up period of 5 years. These movement disorders caused marked persistent disability in four patients. Lesions of the contralateral striatum were identified in patients with dystonic syndromes and lesions of the dentatothalamic outflow in patients with tremors. In three patients who had postoperative basal ganglia lesions after partial removal of astrocytomas, tumor regrowth was later documented. Medical treatment in patients with persistent movement disorders rendered only limited benefit. Two patients improved with botulin injections. In one patient postoperative hemidystonia was alleviated by contralateral thalamotomy.Conclusions. Dystonic syndromes and tremors are the most common movement disorders that occur after craniocerebral and spinal surgery. Postoperative movement disorders can lead to various degrees of functional disability. The pathoanatomical correlations are similar to those described in other patients with secondary movement disorders.

✓ A large ossified spurious meningocele accompanied by recurrent lumbar disc herniation occurred 7 years after posterior intervention for laminectomy and discectomy in a 53-year-old man. The cyst wall, histologically composed of mature bone tissue, was sparsely covered with connective tissue and lined with fibrocyte- or fibroblast-like cells on the inside. The ossified pseudocyst was presumed to have originated from a minute defect in the dura mater which occurred at the time of the first operation.

✓ Intervertebral disc degeneration of any etiology may be associated with the formation of spaces or clefts within the disc. Gas collects within these spaces and can be seen roentgenographically. A case is presented in which intradiscal gas herniated into a connective tissue capsule, displacing the left S-1 nerve root and producing symptoms and signs identical to those of a herniated nucleus pulposus. The pathophysiology of gas within a disc space and the possibility that it may herniate much like the nucleus pulposus is discussed.

Object. Given the virtual absence of histologically detected, clinically unsuspected disease in intervertebral disc specimens, some authors have advocated that histological examination be discontinued. However, the examination of intervertebral disc specimens remains common practice in most pathology laboratories. No cost—benefit analysis of this practice has been made; therefore, the authors' goal in this study was perform such an analysis. Methods. Using the University of Iowa surgical pathology database, 1109 patients who had undergone a laminectomy were identified retrospectively. These cases were classified into four categories based on the patients' preoperative clinical diagnosis and final histopathological diagnosis: insignificant clinical diagnosis/insignificant pathological diagnosis (ICIP), significant clinical diagnosis/insignificant pathological diagnosis (SCIP), significant clinical diagnosis/significant pathological diagnosis (SCSP), and insignificant clinical diagnosis/significant pathological diagnosis (ICSP). A significant clinical diagnosis was defined as one other than a benign, noninfectious indication for laminectomy. A significant pathological diagnosis was a diagnosis other than degenerative changes. The cost—benefit value of performing a histological examination in cases with significant or insignificant clinical diagnoses was examined. The cases were classified as: 1068 ICIP, 17 SCIP, 21 SCSP, and three ICSP. On chart review, in all three cases of ICSP an epidural abscess was identified perioperatively and the subsequent histological diagnosis did not affect patient care. The costs per case of identifying a significant pathological diagnosis with a significant and an insignificant clinical diagnosis were $44.79 and $8811, respectively. Conclusions. Histological examination of intervertebral disc specimens is cost beneficial only if there is a significant preoperative clinical diagnosis.

✓ Cervical spondylosis is a disease that is often attributed to aging and considered the result of degenerative changes in the spine. The idea that there is a genetic predisposition to develop diseases of the skeletal elements of the spine has been discussed previously, but has never been proven conclusively. The authors report three cases of severe cervical spondylosis in patients who are first-degree relatives: a mother and her two sons. All three individuals had cervical disc herniations and stenosis at C3–4, C4–5, C5–6, and C6–7, and all three required decompressive procedures. The location and degree of cervical spondylosis were as similar among these three patients as they have been in identical twins reported in other studies. Such familial inheritance of cervical spondylosis has been reported only once. The existence of familial cervical spondylosis is not an unrealistic proposal because other studies have shown that genetics determines the shape of one's spine and that similar spines tend to degenerate in similar ways. Therefore, genetic counseling for a family such as the one reported here may prove to be of great benefit to warn siblings that they are at high risk for cervical spine injury. However rare it might be, familial cervical spondylosis may be a phenomenon that any spine surgeon should suspect in a family with cervical spine abnormalities found in several members.

Object. The authors aimed to develop management strategies for the treatment of herniated thoracic discs and to define indications for selection of surgical approaches. Symptomatic thoracic discs requiring surgery are rare. Between 1971 and 1995, 71 patients with 82 herniated thoracic discs were surgically treated by the authors. The treated group included 34 men and 37 women whose ages ranged from 19 to 75 years, with a mean age of 48 years. The most common sites of disc herniation requiring surgery were from T-8 to T-11. Evidence of antecedent trauma was present in 37% of the patients. Preoperative symptoms included pain (localized, axial, or radicular) in 54 (76%) of the 71 patients, evidence of myelopathy, that is, motor impairment in 43 (61%), hyperreflexia and spasticity in 41 (58%), sensory impairment in 43 (61%), and bladder dysfunction in 17 (24%). Methods. Radiological diagnosis for the patients in this series was accomplished by means of myelography, computerized tomography myelography, or magnetic resonance imaging. Classification of the disc location into two groups reveals that 94% were centrolateral and 6% were lateral. Evidence of calcification was present in 65% of patients, and in 7% intradural extension was noted at surgery. Ten patients (14%) were found to have multiple herniations. Four surgical approaches were used for the removal of these 82 disc herniations: transthoracic in 49 (60%), transfacet pedicle-sparing in 23 (28%), lateral extracavitary in eight (10%), and transpedicular in two (2%). Postoperative evaluation revealed improvement or resolution of pain in 47 (87%) of 54, hyperreflexia and spasticity in 39 (95%) of 41, sensory changes in 36 (84%) of 43, bowel/bladder dysfunction in 13 (76%) of 17, and motor impairment in 25 (58%) of 43. Complications occurred in a total of 12 (14.6%) of 82 discs treated surgically. Major complications were seen in three patients and included perioperative death from cardiopulmonary compromise, instability requiring further surgery, and an increase in the severity of a preoperative paraparesis. Conclusions. Review of this series, with the attendant complications, together with evaluation of several contemporary thoracic disc series, has facilitated the authors' decision-making process when considering the comprehensive management of these patients, including the selection of a surgical approach.

✓ In preparing this paper, the authors reviewed their experiences with four cases of T1–2 disc herniation as well as the medical literature on the subject. Intervertebral thoracic disc herniations are uncommon and high thoracic disc herniations are rare. In the upper third of the thoracic spine, T1–2 is the most common level for disc ruptures. Four cases of disc herniation at T1–2 that caused T-1 radiculopathy are reported in this paper. In reviewing the literature on thoracic disc herniation, the authors found 27 cases at the T1–2 level, 23 of which were lateral disc herniations that produced radiculopathy and four of which were central disc herniations that caused myelopathy. The clinical signs and symptoms of T-1 radiculopathy are similar to those of C-8 radiculopathy; however, distinguishing features can frequently be found on neurological examination. The T-1 radiculopathy usually involves weakness of the intrinsic muscles of the hand. The motor deficit of C-8 radiculopathy involves the intrinsic muscles of the hand and most of the flexors and extensors of the fingers and wrist. The T-1 radiculopathy may produce Horner's syndrome (oculosympathetic paralysis) and diminished sensation in the axilla, which are not found with C-8 radiculopathy. In clinical presentation as well as in treatment, the lateral T1–2 disc herniation resembles a cervical disc herniation, whereas the central T1–2 disc herniation displays the usual appearance of a thoracic disc herniation.

✓ Chylous fistula resulting from intraoperative injury to the cervical thoracic duct is well described as a complication of neck dissection. However, injury to the thoracic duct during spinal surgery is rarely reported. The authors present the first case of thoracic duct injury occurring during cervical discectomy and fusion via an anterior approach. The anomalous location of the terminal arch of the thoracic duct in this patient contributed to the complication. The morbidity of chyle leakage is minimized by its early recognition, a thorough understanding of lymphatic system anatomy, and aggressive management of the thoracic duct injury.

✓ In an effort to make thoracic discectomy simple and less invasive while using direct visualization, a 70°-angled lens endoscope has been adopted to visualize the ventral aspect of the spinal cord dura mater during microsurgical thoracic discectomy via a transpedicular approach. The patient is positioned in a 60° forwardly inclined lateral position with the side of the lesion facing upward. After radiographic corroboration of the correct level, a transpedicular approach is made using a 1.5-cm-diameter tubular retractor through a 2-cm-long paramedian transverse skin incision. With the aid of an operating microscope, the ipsilateral facet joint, including the upper portion of the pedicle, is removed using a high-speed drill, thus exposing the neural foramen, intervertebral disc, and upper portion of the pedicle leading to the vertebral bodies. When the herniated disc and bone spur have been removed laterally in relation to the spinal cord, creating a cavity under the operating microscope, a 4-mm-diameter rigid endoscope with a 70°-angled lens is mounted to an endoscope holder so that the ventral aspect of the spinal cord dura mater can be visualized directly. With the aid of direct endoscopic visualization, the disc and bone spur, which compress the spinal cord anteriorly, are pushed away toward a cavity created at the intervertebral space and are removed using a downward-biting long-armed curette. Patients with myelopathy are kept overnight in the hospital; however, those with radiculopathy are discharged home on the same day as their operation. The surgical technique and two illustrative cases are reported.

✓ The authors report the case of a 48-year-old woman who experienced spontaneous resolution of a large herniated disc at C6–7. Spontaneous resolution of a herniated lumbar disc was first documented by computerized tomography. This case is another example of a rare spontaneous resolution of a cervical disc herniation documented by magnetic resonance imaging.

✓ The purpose of this study was to evaluate the feasibility and efficacy of arthroscopic decompression of lateral recess stenosis, determine potential associated complications, and present an alternative method to access the lateral recess of the lumbar spine. Forty patients were selected in whom the authors found clinical and computerized tomography evidence of lateral recess stenosis and sequestered foraminal herniations. All 40 were treated with a posterolateral arthroscopic technique, and 38 were available for this follow-up evaluation. A satisfactory result was obtained in 31 patients (82%). No neurovascular complications were encountered; however, other complications included an infection of the disc space in one patient and a causalgic-type pain in the involved extremity in four patients. The associated postoperative morbidity in this group of patients was minimal and resulted in rapid rehabilitation and return of patients to preoperative functioning level.

✓ The authors present the case of a failed titanium anterior cervical spine plate. The plate was contoured during implantation. Analysis of the failed implant with electron microscopy showed no metallurgical flaw to have caused the plate fracture. A crack was apparently initiated with the contouring of the plate. It was located at the weakest point in the plate (the position of the intermediate screw hole), and with subsequent stress, it propagated and led to fracture. Techniques for avoiding failure of this type are discussed.

✓ This study was undertaken to determine and compare indications and relative benefits of various surgical approaches in 170 patients (average age 55 years) with far-lateral herniated lumbar discs, identified by magnetic resonance (MR) imaging and computerized tomography (CT) and operated on between 1984 and 1994. Essentially three surgical procedures were performed: complete facetectomy in 73 patients, laminotomy with medial facetectomy in 39 patients, and intertransverse discectomy (also known as ITT) in 58 patients. Follow-up periods averaged 5 years (range 0.5–10 years). Outcomes were scored as excellent (no deficit), good (mild radiculopathy), fair (moderate radiculopathy), and poor (unchanged or worse).Overall, excellent and good results were achieved in 73 and 51 patients, respectively, and fair and poor results in 26 and 20, respectively. There was little difference among the results encountered for the three major surgical groups: 79% of the intertransverse (ITT) group had good-to-excellent outcomes, as compared with 70% of the facetectomy group, and 68% of the group who underwent at minimum laminotomy, and additional hemilaminectomy or laminectomy with medial facetectomy. Results were the same for the 121 patients followed for more than 2 years and for the 49 patients studied for under 2 years.In the management of far-lateral discs, total facetectomy provides the best exposure, but increases the risk of instability. Laminotomy and medial facetectomy uncover the lateral and subarticular recess and preserve stability, but visualization of the far-lateral compartment is often inadequate. The intertransverse approach offers extensive far-lateral but not medial intraforaminal exposure, while also preserving stability.Full facetectomy, laminotomy with medial facetectomy, and the intertransverse approaches yielded nearly comparable outcomes in far-lateral disc surgery. Only the full facetectomy exposes the entire course of the nerve root both medially and laterally, whereas the intertransverse procedure provides direct exposure of the far-lateral compartment alone.It is important to select the correct approach or combination of approaches to address attendant complicating factors such as spinal stenosis, spondyloarthrosis, and degenerative spondylolisthesis identified on CT and MR studies.

This report discusses the clinical features of a patient who presented with an L-3 radiculopathy in whom magnetic resonance imaging demonstrated what appeared to be a nerve sheath tumor in an extraforaminal location on the L-3 nerve root. A lateral intermuscular approach to excise the lesion was used to preserve the facet joint. Histological examination of the intraneural lesion revealed degenerative disc fragments. The authors hypothesize that the structure of the annulus fibrosus in the upper lumbar region predisposes these regions to lateral herniation. Furthermore, it is proposed that the lateral disc herniation allowed the disc fragments to erode through the epineurium of the neural sheath. This case expands the differential diagnosis of fusiform enlargement of nerves to include disc herniation.

✓ One hundred fifty patients underwent spinal surgery for radiculopathy; of these, 120 underwent lumbar surgery and 30 had cervical operations. All of the surgeries were performed to alleviate symptoms due to disc herniation, spondylosis, or both. During the surgical procedures continuous intraoperative electromyograph recordings were taken from the muscle corresponding to the involved nerve root. In baseline recordings taken in the operating room 10 minutes before lumbar surgery, electrical discharge or firing was recorded from the muscle in 18% (22 of 120 patients) of the cases. Once the nerve was decompressed, muscle firing ceased. Electrical discharges were produced with regularity on nerve root retraction. This study concludes that continuous electromyograph monitoring can be accomplished easily and yields valuable information that indicates when the nerve root is adequately decompressed or when undue retraction is exerted on the root.