Kurt M. Eichholz

Surgical site infection rates after minimally invasive spinal surgery

OBJECT Postoperative surgical site infections (SSIs) have been reported after 2-6% of spinal surgeries in most large series. The incidence of SSI can be < 1% after decompressive procedures and > 10% after instrumented fusions. Anecdotal evidence has suggested that there is a lower rate of SSI when minimally invasive techniques are used. METHODS A retrospective review of prospectively collected databases of consecutive patients who underwent minimally invasive spinal surgery was performed. Minimally invasive spinal surgery was defined as any spinal procedure performed through a tubular retractor system. All surgeries were performed under standard sterile conditions with preoperative antibiotic prophylaxis. The databases were reviewed for any infectious complications. Cases of SSI were identified and reviewed for clinically relevant details. The incidence of postoperative SSIs was then calculated for the entire cohort as well as for subgroups based on the type of procedure performed, and then compared with an analogous series selected from an extensive literature review. RESULTS The authors performed 1338 minimally invasive spinal surgeries in 1274 patients of average age 55.5 years. The primary diagnosis was degenerative in nature in 93% of cases. A single minimally invasive spinal surgery procedure was undertaken in 1213 patients, 2 procedures in 58, and 3 procedures in 3 patients. The region of surgery was lumbar in 85%, cervical in 12%, and thoracic in 3%. Simple decompressive procedures comprised 78%, instrumented arthrodeses 20%, and minimally invasive intradural procedures 2% of the collected cases. Three postoperative SSIs were detected, 2 were superficial and 1 deep. The procedural rate of SSI for simple decompression was 0.10%, and for minimally invasive fusion/fixation was 0.74%. The total SSI rate for the entire group was only 0.22%. CONCLUSIONS Minimally invasive spinal surgery techniques may reduce postoperative wound infections as much as 10-fold compared with other large, modern series of open spinal surgery published in the literature.

Minimally invasive lumbar spinal decompression in the elderly: outcomes of 50 patients aged 75 years and older.

OBJECTIVELumbar spinal stenosis and spondylosis are major causes of morbidity among the elderly. Surgical decompression is an effective treatment, but many elderly patients are not considered as candidates for surgery based on age or comorbidities. Minimally invasive surgical techniques have recently been developed and used successfully for the treatment of lumbar spinal disease. Our objective was to examine the safety and efficacy of minimally invasive lumbar spinal surgery for elderly patients. METHODSWe reviewed demographic information, pre- and postoperative Visual Analog Scale pain scores, Oswestry Disability Index scores, and Short-Form 36 scores of prospectively accrued patients who underwent minimally invasive decompression of lumbar degenerative disease at two institutions between January 2002 and December 2005. Data from patients who were at least 75 years old were selected. Statistical analysis methods included paired t test, multiple linear regression, and linear mixed effects modeling. RESULTSFifty-seven patients with a mean age of 81 years met the study criteria (median follow-up period, 7 mo; mean follow-up period, 10 mo). No major complications or deaths occurred. Fifty patients had sufficient outcomes data for analysis. Visual Analog Scale pain scores decreased from 5.7 to 2.2 for back pain and from 5.7 to 2.3 for symptomatic leg pain (P < 0.05). Oswestry Disability Index scores decreased from 48 to 27; Short-Form 36 Body Pain and Physical Function scores also showed statistically significant improvements after surgery (P < 0.05). The longitudinal analysis demonstrated durability of the symptom relief. CONCLUSIONMinimally invasive lumbar spine decompression is a safe and efficacious treatment for elderly patients with spinal stenosis and spondylosis. Elderly patients should be considered good candidates for lumbar surgical decompression using minimally invasive techniques.

Minimally invasive posterolateral thoracic corpectomy: cadaveric feasibility study and report of four clinical cases.

OBJECTIVETo demonstrate the feasibility of and initial clinical experience with a novel minimally invasive posterolateral thoracic corpectomy technique. METHODSSeven procedures were performed on 6 cadavers to determine the feasibility of thoracic corpectomy using a minimally invasive approach. The posterolateral thoracic corpectomies were performed with expandable 22 mm diameter tubular retractor paramedian incisions. The posterolateral aspects of the vertebral bodies were accessed extrapleurally, and complete corpectomies were performed. Intraprocedural fluoroscopy and postoperative computed tomography were used to assess the degree of decompression. In addition, 2 clinical cases of T6 burst fracture, 1 T4–T5 plasmacytoma, and 1 T12 colon cancer metastasis were treated using this minimally invasive approach. RESULTSIn the cadaveric study, an average of 93% of the ventral canal and 80% of the corresponding vertebral body were removed. The pleura and intrathoracic contents were not violated. Adequate exposure was obtained to allow interbody grafting between the adjacent vertebral bodies. The procedures were successfully performed in the 4 clinical cases using a minimally invasive technique, and the patients demonstrated good outcomes. CONCLUSIONBased on this study, minimally invasive posterolateral thoracic corpectomy safely and successfully allows complete spinal canal decompression without the tissue disruption associated with open thoracotomy. This approach may improve the complication rates that accompany open or even thoracoscopic approaches for thoracic corpectomy and may even allow surgical intervention in patients with significant comorbidities.

MINIMALLY INVASIVE POSTERIOR OSTEOTOMIES

OBJECTIVESurgery for thoracolumbar deformity can lead to significant muscle injury, excessive blood loss, and severe postoperative pain. The aim of the following studies was to determine the feasibility of minimally invasive posterior thoracic corpectomy and thoracolumbar osteotomy techniques for deformity in human cadavers and select clinical cases. METHODSHuman cadaveric specimens were procured for thoracic corpectomy and Smith-Petersen and pedicle subtraction osteotomy using a minimally invasive approach. Post-procedural computed tomography was used to assess the degree of decompression following corpectomy and the extent of bone resection after osteotomy. Pre and post-osteotomy closure Cobb angles were measured to evaluate the degree of correction achieved. RESULTSThe minimally invasive lateral extracavitary approach for thoracic corpectomy provided adequate exposure and allowed excellent spinal canal decompression while minimizing tissue disruption. Nearly complete osteotomies of both types could be achieved through a tubular retractor with a modest change in Cobb angle. CONCLUSIONThese techniques may play a role in deformity surgery for select cases with further technological advancements.

Minimally invasive thoracic microendoscopic diskectomy: surgical technique and case series.

OBJECTIVE To present operative details and clinical follow-up of a series of patients with thoracic disk herniation treated with the minimally invasive technique of thoracic microendoscopic diskectomy (TMED). METHODS TMED was performed in 16 consecutive patients (age range, 18-79 years old) with 18 thoracic disk herniations. One patient with a calcified herniation in a direct ventral location was not included in this series. Patients were positioned prone, and a tubular retractor system was placed through a muscle dilating approach. The procedure was performed with endoscopic visualization. Outcomes were assessed using modified McNab criteria. RESULTS There were no complications, and no case required conversion to an open procedure. The mean operative time was 153 minutes per level, and mean blood loss was 69 mL per level. Mean hospital stay was 21 hours. At a mean follow-up of 24 months (median, 22 months), 13 patients (81%) had excellent or good outcomes, 1 patient (6%) had a fair outcome, and 2 patients (13%) had poor outcomes. The two patients with poor outcomes had neurologic diagnoses (multiple sclerosis and multiple systems atrophy) that were ultimately found to be responsible for their symptoms and deficits. CONCLUSIONS TMED is a safe and effective minimally invasive posterolateral approach for the treatment of thoracic disk herniations that lacks the morbidity associated with traditional approaches.

Is the X STOP ® interspinous implant a safe and effective treatment for neurogenic intermittent claudication?

Is the X STOP ® interspinous implant a safe and effective treatment for neurogenic intermittent claudication?

A minimally invasive approach to defects of the pars interarticularis: Restoring function in competitive athletes

OBJECTIVES To understand that young athletes have a higher incidence of pars interarticularis defects than the general population. This may be due to an immature spine put under higher stress loads at an early age. Traditionally, surgery was reserved for those who failed conservative therapy, and consisted of open exposure, bone grafting and placement of pedicle screws. This leads to a long recovery period and limited ability to return to competitive sport. METHODS Four collegiate and professional level athletes, three high school athletes, and one member of the National Guard presented with back pain from spondylolysis without spondylolisthesis. All underwent minimally invasive surgery (MIS) to directly repair the pars defect, for a total of sixteen pars defects repaired in eight patients. Described is an application of a MIS pars repair technique that has not previously been reported, which recreates the normal anatomy rather fusing across a motion segment. RESULTS Five patients were discharged the day following surgery and three were discharged on postoperative day 2. Six of the patients returned to their previous level of competitiveness. Two were unable to achieve the same level of play, both of whom failed to fuse the spondylolysis. Patients all initially reported clinical improvement postoperatively and there was overall mean improvement on patient reported outcome measures (SF36 physical and mental component scores, visual analog scale, and Oswestry disability index). CONCLUSION MIS advantages include less muscle tissue disruption and restoration of the natural anatomy. This leads to a more rapid recovery, decreased perioperative pain, minimal blood loss, earlier mobilization and decreased hospital length of stay. Overall this allows the athlete to start therapy earlier and return to competition sooner and at his/her pre-operative competitive level. The described MIS repair technique outcomes are similar to those that have been reported in the literature and have allowed a high rate of return to athletics in high performing patients; critical to their quality of life.

Minimally invasive insertion of syringosubarachnoid shunt for posttraumatic syringomyelia: technical case report.

OBJECTIVE Symptomatic posttraumatic syringomyelia affects up to 10% of patients with spinal cord injuries and manifests in a delayed manner as progressive sensorimotor changes below the level of the syrinx. Syrinx shunting, and in particular syringosubarachnoid shunting (SSAS), provides neurological improvement or stabilization in at least 50% of these patients. Given the debilitated condition of many of these patients, a minimally invasive approach to the insertion of these devices is desirable. We provide the first report of an SSAS inserted in a minimally invasive fashion through a tubular retractor. PATIENTS AND METHODS A 27-year-old woman presented 4 years after C6 to C7 fracture dislocation and incomplete spinal cord injury with increasing pain and spasticity below the midthoracic region. Magnetic resonance imaging scan revealed a midthoracic syrinx that had enlarged on serial imaging. SSAS was inserted using a minimally invasive technique via the X-Tube retractor (Medtronic Sofamor Danek, Memphis, TN). Through a 2.5-cm incision, hemilaminotomy was performed, and a midline durotomy and myelotomy were opened for SSAS insertion under microscopic visualization. RESULTS Intraoperative ultrasonography revealed successful syrinx decompression after SSAS insertion. The operative time was 150 minutes and estimated blood loss was less than 100 mL. The patient was mobilized on postoperative Day 1 and was discharged 38.5 hours after surgery with resolution of her preoperative symptoms. Postoperative magnetic resonance imaging scan revealed excellent decompression of the syrinx, and through 1 year of follow-up, the patient has had no recurrence of her syrinx-related symptoms. CONCLUSION This is the first report of minimal-access insertion of an SSAS. The minimally invasive technique appears to be a safe and effective means of implanting an SSAS. This approach allows for diminished blood loss and early mobilization and transfer to rehabilitation units for these patients.

The Technological Development of Minimally Invasive Spine Surgery

Minimally invasive spine surgery has its roots in the mid-twentieth century with a few surgeons and a few techniques, but it has now developed into a large field of progressive spinal surgery. A wide range of techniques are now called “minimally invasive,” and case reports are submitted constantly with new “minimally invasive” approaches to spinal pathology. As minimally invasive spine surgery has become more mainstream over the past ten years, in this paper we discuss its history and development.

Cadaveric evaluation of minimally invasive posterolateral thoracic corpectomy: a comparison of 3 approaches.

Study Design A cadaver study comparing 3 different minimally invasive approaches to the anterior thoracic spine. Objective To assess the feasibility of minimally invasive thoracic corpectomy from a posterolateral approach and to compare surgical results from 3 approaches. Summary of Background Data Traditional posterolateral approaches to the thoracic spine are effective but are associated with a high rate of operative morbidity. Methods Thoracic corpectomies were performed using a modified tubular retractor starting at 3, 6, and 9 cm off of midline. Postoperative computed tomography scans were performed and analyzed to assess the extent of corpectomy and ventral decompression. Results From 3 to 6 to 9 cm, a significant difference in extent of corpectomy (65.8%, 81.5%, and 82.6%, P=0.02) and ventral decompression (83.6%, 90.4%, 94.6%, P=0.05) was noted between 3 cm and the more lateral approaches. The 9 cm approach required more rib resection and average working distances of 8.4 to 11.3 cm, which made the procedure more difficult technically and less suited to the length of standard instruments. Conclusions Minimally invasive thoracic corpectomy is feasible and a 6 cm approach off of midline appears optimal.